1
|
Van Loh BM, Yaw AM, Breuer JA, Jackson B, Nguyen D, Jang K, Ramos F, Ho EV, Cui LJ, Gillette DLM, Sempere LF, Gorman MR, Tonsfeldt KJ, Mellon PL, Hoffmann HM. The transcription factor VAX1 in VIP neurons of the suprachiasmatic nucleus impacts circadian rhythm generation, depressive-like behavior, and the reproductive axis in a sex-specific manner in mice. Front Endocrinol (Lausanne) 2023; 14:1269672. [PMID: 38205198 PMCID: PMC10777845 DOI: 10.3389/fendo.2023.1269672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 11/28/2023] [Indexed: 01/12/2024] Open
Abstract
Background The suprachiasmatic nucleus (SCN) within the hypothalamus is a key brain structure required to relay light information to the body and synchronize cell and tissue level rhythms and hormone release. Specific subpopulations of SCN neurons, defined by their peptide expression, regulate defined SCN output. Here we focus on the vasoactive intestinal peptide (VIP) expressing neurons of the SCN. SCN VIP neurons are known to regulate circadian rhythms and reproductive function. Methods To specifically study SCN VIP neurons, we generated a novel knock out mouse line by conditionally deleting the SCN enriched transcription factor, Ventral Anterior Homeobox 1 (Vax1), in VIP neurons (Vax1Vip; Vax1fl/fl:VipCre). Results We found that Vax1Vip females presented with lengthened estrous cycles, reduced circulating estrogen, and increased depressive-like behavior. Further, Vax1Vip males and females presented with a shortened circadian period in locomotor activity and ex vivo SCN circadian period. On a molecular level, the shortening of the SCN period was driven, at least partially, by a direct regulatory role of VAX1 on the circadian clock genes Bmal1 and Per2. Interestingly, Vax1Vip females presented with increased expression of arginine vasopressin (Avp) in the paraventricular nucleus, which resulted in increased circulating corticosterone. SCN VIP and AVP neurons regulate the reproductive gonadotropin-releasing hormone (GnRH) and kisspeptin neurons. To determine how the reproductive neuroendocrine network was impacted in Vax1Vip mice, we assessed GnRH sensitivity to a kisspeptin challenge in vivo. We found that GnRH neurons in Vax1Vip females, but not males, had an increased sensitivity to kisspeptin, leading to increased luteinizing hormone release. Interestingly, Vax1Vip males showed a small, but significant increase in total sperm and a modest delay in pubertal onset. Both male and female Vax1Vip mice were fertile and generated litters comparable in size and frequency to controls. Conclusion Together, these data identify VAX1 in SCN VIP neurons as a neurological overlap between circadian timekeeping, female reproduction, and depressive-like symptoms in mice, and provide novel insight into the role of SCN VIP neurons.
Collapse
Affiliation(s)
- Brooke M. Van Loh
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Alexandra M. Yaw
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Joseph A. Breuer
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Brooke Jackson
- Department of Radiology and Precision Health Program, Michigan State University, East Lansing, MI, United States
| | - Duong Nguyen
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Krystal Jang
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Fabiola Ramos
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Emily V. Ho
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Laura J. Cui
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Dominique L. M. Gillette
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Lorenzo F. Sempere
- Department of Radiology and Precision Health Program, Michigan State University, East Lansing, MI, United States
| | - Michael R. Gorman
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Karen J. Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Pamela L. Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Hanne M. Hoffmann
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| |
Collapse
|
2
|
Cassin J, Stamou MI, Keefe KW, Sung KE, Bojo CC, Tonsfeldt KJ, Rojas RA, Ferreira Lopes V, Plummer L, Salnikov KB, Keefe DL, Ozata M, Genel M, Georgopoulos NA, Hall JE, Crowley WF, Seminara SB, Mellon PL, Balasubramanian R. Heterozygous mutations in SOX2 may cause idiopathic hypogonadotropic hypogonadism via dominant-negative mechanisms. JCI Insight 2023; 8:e164324. [PMID: 36602867 PMCID: PMC9977424 DOI: 10.1172/jci.insight.164324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 12/29/2022] [Indexed: 01/06/2023] Open
Abstract
Pathogenic SRY-box transcription factor 2 (SOX2) variants typically cause severe ocular defects within a SOX2 disorder spectrum that includes hypogonadotropic hypogonadism. We examined exome-sequencing data from a large, well-phenotyped cohort of patients with idiopathic hypogonadotropic hypogonadism (IHH) for pathogenic SOX2 variants to investigate the underlying pathogenic SOX2 spectrum and its associated phenotypes. We identified 8 IHH individuals harboring heterozygous pathogenic SOX2 variants with variable ocular phenotypes. These variant proteins were tested in vitro to determine whether a causal relationship between IHH and SOX2 exists. We found that Sox2 was highly expressed in the hypothalamus of adult mice and colocalized with kisspeptin 1 (KISS1) expression in the anteroventral periventricular nucleus of adult female mice. In vitro, shRNA suppression of mouse SOX2 protein in Kiss-expressing cell lines increased the levels of human kisspeptin luciferase (hKiss-luc) transcription, while SOX2 overexpression repressed hKiss-luc transcription. Further, 4 of the identified SOX2 variants prevented this SOX2-mediated repression of hKiss-luc. Together, these data suggest that pathogenic SOX2 variants contribute to both anosmic and normosmic forms of IHH, attesting to hypothalamic defects in the SOX2 disorder spectrum. Our study describes potentially novel mechanisms contributing to SOX2-related disease and highlights the necessity of SOX2 screening in IHH genetic evaluation irrespective of associated ocular defects.
Collapse
Affiliation(s)
- Jessica Cassin
- Department of Obstetrics, Gynecology, and Reproductive Sciences; Center for Reproductive Science and Medicine; and
- Center for Circadian Biology, University of California, San Diego, La Jolla, California, USA
| | - Maria I. Stamou
- Massachusetts General Hospital Harvard Center for Reproductive Medicine and Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Kimberly W. Keefe
- Center for Infertility and Reproductive Surgery, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Kaitlin E. Sung
- Department of Obstetrics, Gynecology, and Reproductive Sciences; Center for Reproductive Science and Medicine; and
| | - Celine C. Bojo
- Department of Obstetrics, Gynecology, and Reproductive Sciences; Center for Reproductive Science and Medicine; and
| | - Karen J. Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences; Center for Reproductive Science and Medicine; and
- Center for Circadian Biology, University of California, San Diego, La Jolla, California, USA
| | - Rebecca A. Rojas
- Massachusetts General Hospital Harvard Center for Reproductive Medicine and Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Vanessa Ferreira Lopes
- Massachusetts General Hospital Harvard Center for Reproductive Medicine and Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Lacey Plummer
- Center for Infertility and Reproductive Surgery, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Kathryn B. Salnikov
- Massachusetts General Hospital Harvard Center for Reproductive Medicine and Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - David L. Keefe
- Center for Infertility and Reproductive Surgery, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | | | - Myron Genel
- Section of Pediatric Endocrinology, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Neoklis A. Georgopoulos
- Division of Endocrinology, Department of Medicine, University of Patras Medical School, Patras, Greece
| | - Janet E. Hall
- National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - William F. Crowley
- Endocrine Unit, Department of Medicine, and Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Stephanie B. Seminara
- Massachusetts General Hospital Harvard Center for Reproductive Medicine and Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Pamela L. Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences; Center for Reproductive Science and Medicine; and
- Center for Circadian Biology, University of California, San Diego, La Jolla, California, USA
| | - Ravikumar Balasubramanian
- Massachusetts General Hospital Harvard Center for Reproductive Medicine and Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| |
Collapse
|
3
|
Lavalle SN, Chou T, Hernandez J, Naing NCP, He MY, Tonsfeldt KJ, Mellon PL. Deletion of the homeodomain gene Six3 from kisspeptin neurons causes subfertility in female mice. Mol Cell Endocrinol 2022; 546:111577. [PMID: 35121076 PMCID: PMC8934285 DOI: 10.1016/j.mce.2022.111577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/13/2022] [Accepted: 01/30/2022] [Indexed: 01/27/2023]
Abstract
The homeodomain transcription factor SIX3 is a known regulator of eye, nose, and forebrain development, and has recently been implicated in female reproduction. Germline heterozygosity of SIX3 is sufficient to cause subfertility, but the cell populations that mediate this role are unknown. The neuropeptide kisspeptin is a critical component of the reproductive axis and plays roles in sexual maturation, ovulation, and the maintenance of gonadotropin secretion. We used Cre-Lox technology to remove Six3 specifically from kisspeptin neurons in mice to test the hypothesis that SIX3 in kisspeptin neurons is required for reproduction. We found that loss of Six3 in kisspeptin neurons causes subfertility and estrous cycle irregularities in females, but no effect in males. Overall, we find that SIX3 expression in kisspeptin neurons is an important contributor to female fertility.
Collapse
Affiliation(s)
- Shanna N Lavalle
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Teresa Chou
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Jacqueline Hernandez
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Nay Chi P Naing
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Michelle Y He
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Karen J Tonsfeldt
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, And Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
4
|
Abstract
For billions of years before electric light was invented, life on Earth evolved under the pattern of light during the day and darkness during the night. Through evolution, nearly all organisms internalized the temporal rhythm of Earth's 24-hour rotation and evolved self-sustaining biological clocks with a ~24-hour rhythm. These internal rhythms are called circadian rhythms, and the molecular constituents that generate them are called molecular circadian clocks. Alignment of molecular clocks with the environmental light-dark rhythms optimizes physiology and behavior. This phenomenon is particularly true for reproductive function, in which seasonal breeders use day length information to time yearly changes in fertility. However, it is becoming increasingly clear that light-induced disruption of circadian rhythms can negatively impact fertility in nonseasonal breeders as well. In particular, the luteinizing hormone surge promoting ovulation is sensitive to circadian disruption. In this review, we will summarize our current understanding of the neuronal networks that underlie circadian rhythms and the luteinizing hormone surge.
Collapse
Affiliation(s)
- Karen J Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
- Correspondence: Pamela L. Mellon, Ph.D., University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA 92093-0674.
| | - Hanne M Hoffmann
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, 766 Service Road, East Lansing, MI, 48824, USA
| |
Collapse
|
5
|
Tonsfeldt KJ, Cui LJ, Lee J, Walbeek TJ, Brusman LE, Jin Y, Mieda M, Gorman MR, Mellon PL. Female fertility does not require Bmal1 in suprachiasmatic nucleus neurons expressing arginine vasopressin, vasoactive intestinal peptide, or neuromedin-S. Front Endocrinol (Lausanne) 2022; 13:956169. [PMID: 35992114 PMCID: PMC9389073 DOI: 10.3389/fendo.2022.956169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/06/2022] [Indexed: 01/27/2023] Open
Abstract
Disruptions to the circadian system alter reproductive capacity, particularly in females. Mice lacking the core circadian clock gene, Bmal1, are infertile and have evidence of neuroendocrine disruption including the absence of the preovulatory luteinizing hormone (LH) surge and enhanced responsiveness to exogenous kisspeptin. Here, we explore the role of Bmal1 in suprachiasmatic nucleus (SCN) neuron populations known to project to the neuroendocrine axis. We generated four mouse lines using Cre/Lox technology to create conditional deletion of Bmal1 in arginine vasopressin (Bmal1fl/fl:Avpcre ), vasoactive intestinal peptide (Bmal1fl/fl:Vipcre ), both (Bmal1fl/fl:Avpcre+Vipcre ), and neuromedin-s (Bmal1fl/fl:Nmscre ) neurons. We demonstrate that the loss of Bmal1 in these populations has substantial effects on home-cage circadian activity and temperature rhythms. Despite this, we found that female mice from these lines demonstrated normal estrus cycles, fecundity, kisspeptin responsiveness, and inducible LH surge. We found no evidence of reproductive disruption in constant darkness. Overall, our results indicate that while conditional Bmal1 knockout in AVP, VIP, or NMS neurons is sufficient to disrupted locomotor activity, this disruption is insufficient to recapitulate the neuroendocrine reproductive effects of the whole-body Bmal1 knockout.
Collapse
Affiliation(s)
- Karen J. Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Laura J. Cui
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Jinkwon Lee
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Thijs J. Walbeek
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States
| | - Liza E. Brusman
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Ye Jin
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Michihiro Mieda
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Michael R. Gorman
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States
| | - Pamela L. Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
- *Correspondence: Pamela L. Mellon,
| |
Collapse
|
6
|
Meadows JD, Breuer JA, Lavalle SN, Hirschenberger MR, Patel MM, Nguyen D, Kim A, Cassin J, Gorman MR, Welsh DK, Mellon PL, Hoffmann HM. Deletion of Six3 in post-proliferative neurons produces weakened SCN circadian output, improved metabolic function, and dwarfism in male mice. Mol Metab 2021; 57:101431. [PMID: 34974160 PMCID: PMC8810556 DOI: 10.1016/j.molmet.2021.101431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/17/2021] [Accepted: 12/29/2021] [Indexed: 01/27/2023] Open
Abstract
OBJECTIVE The increasing prevalence of obesity makes it important to increase the understanding of the maturation and function of the neuronal integrators and regulators of metabolic function. METHODS Behavioral, molecular, and physiological analyses of transgenic mice with Sine oculis 3 (Six3) deleted in mature neurons using the Synapsincreallele. RESULTS Conditional deletion of the homeodomain transcription factor Six3 in mature neurons causes dwarfism and weakens circadian wheel-running activity rhythms but increases general activity at night, and improves metabolic function, without impacting pubertal onset or fertility in males. The reduced growth in 6-week-old Six3fl/fl:Synapsincre (Six3syn) males correlates with increased somatostatin (SS) expression in the hypothalamus and reduced growth hormone (GH) in the pituitary. In contrast, 12-week-old Six3syn males have increased GH release, despite an increased number of the inhibitory SS neurons in the periventricular nucleus. GH is important in glucose metabolism, muscle function, and bone health. Interestingly, Six3syn males have improved glucose tolerance at 7, 12, and 18 weeks of age, which, in adulthood, is associated with increased % lean mass and increased metabolic rates. Further, 12-week-old Six3syn males have reduced bone mineralization and a lower bone mineral density, indicating that reduced GH levels during early life cause a long-term reduction in bone mineralization. CONCLUSION Our study points to the novel role of Six3 in post-proliferative neurons to regulate metabolic function through SS neuron control of GH release.
Collapse
Affiliation(s)
- Jason D. Meadows
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA,Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Joseph A. Breuer
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA,Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Shanna N. Lavalle
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA,Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Michael R. Hirschenberger
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, 766 Service Road, East Lansing, MI, 48824, USA
| | - Meera M. Patel
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Duong Nguyen
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, 766 Service Road, East Lansing, MI, 48824, USA
| | - Alyssa Kim
- Department of Plant Soil and Microbial Sciences, Michigan State University, and CANR Statistical Consulting Center, Michigan State University, East Lansing, MI, 48824, USA
| | - Jessica Cassin
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Michael R. Gorman
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA,Department of Psychology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - David K. Welsh
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA,Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA,Veterans Affairs San Diego Healthcare System, San Diego, CA, 92161, USA
| | - Pamela L. Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA,Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Hanne M. Hoffmann
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA,Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA,Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, 766 Service Road, East Lansing, MI, 48824, USA,Corresponding author. Michigan State University Interdisciplinary Science and Technology Building #3010 766 Service Road, East Lansing, MI 48224, USA.
| |
Collapse
|
7
|
Ho EV, Shi C, Cassin J, He MY, Nguyen RD, Ryan GE, Tonsfeldt KJ, Mellon PL. Reproductive Deficits Induced by Prenatal Antimüllerian Hormone Exposure Require Androgen Receptor in Kisspeptin Cells. Endocrinology 2021; 162:6371276. [PMID: 34529765 PMCID: PMC8507963 DOI: 10.1210/endocr/bqab197] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Indexed: 11/19/2022]
Abstract
Polycystic ovary syndrome (PCOS) is a common reproductive disorder characterized by elevated androgens and antimüllerian hormone (AMH). These hormones remain elevated throughout pregnancy, and potential effects of hormone exposure on offspring from women with PCOS remain largely unexplored. Expanding on recent reports of prenatal AMH exposure in mice, we have fully characterized the reproductive consequences of prenatal AMH (pAMH) exposure throughout the lifespan of first- and second-generation offspring of both sexes. We also sought to elucidate mechanisms underlying pAMH-induced reproductive effects. There is a known reciprocal relationship between AMH and androgens, and in PCOS and PCOS-like animal models, androgen feedback is dysregulated at the level of the hypothalamus. Kisspeptin neurons express androgen receptors and play a critical role in sexual development and function. We therefore hypothesized that pAMH-induced reproductive phenotypes would be mediated by androgen signaling at the level of kisspeptin cells. We tested the pAMH model in kisspeptin-specific androgen receptor knockout (KARKO) mice and found that virtually all pAMH-induced phenotypes assayed are eliminated in KARKO offspring compared to littermate controls. By demonstrating the necessity of androgen receptor in kisspeptin cells to induce pAMH phenotypes, we have advanced understanding of the interactions between AMH and androgens in the context of prenatal exposure, which could have significant implications for children of women with PCOS.
Collapse
Affiliation(s)
- Emily V Ho
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Chengxian Shi
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Jessica Cassin
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Michelle Y He
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Ryan D Nguyen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Genevieve E Ryan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Karen J Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
- Correspondence: Pamela L. Mellon, PhD, Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0674, USA.
| |
Collapse
|
8
|
Hoffmann HM, Meadows JD, Breuer JA, Yaw AM, Nguyen D, Tonsfeldt KJ, Chin AY, Devries BM, Trang C, Oosterhouse HJ, Lee JS, Doser JW, Gorman MR, Welsh DK, Mellon PL. The transcription factors SIX3 and VAX1 are required for suprachiasmatic nucleus circadian output and fertility in female mice. J Neurosci Res 2021; 99:2625-2645. [PMID: 34212416 PMCID: PMC8577618 DOI: 10.1002/jnr.24864] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 05/10/2021] [Indexed: 12/12/2022]
Abstract
The homeodomain transcription factors sine oculis homeobox 3 (Six3) and ventral anterior homeobox 1 (Vax1) are required for brain development. Their expression in specific brain areas is maintained in adulthood, where their functions are poorly understood. To identify the roles of Six3 and Vax1 in neurons, we conditionally deleted each gene using Synapsincre , a promoter targeting maturing neurons, and generated Six3syn and Vax1syn mice. Six3syn and Vax1syn females, but not males, had reduced fertility, due to impairment of the luteinizing hormone (LH) surge driving ovulation. In nocturnal rodents, the LH surge requires a precise timing signal from the brain's circadian pacemaker, the suprachiasmatic nucleus (SCN), near the time of activity onset. Indeed, both Six3syn and Vax1syn females had impaired rhythmic SCN output, which was associated with weakened Period 2 molecular clock function in both Six3syn and Vax1syn mice. These impairments were associated with a reduction of the SCN neuropeptide vasoactive intestinal peptide in Vax1syn mice and a modest weakening of SCN timekeeping function in both Six3syn and Vax1syn mice. Changes in SCN function were associated with mistimed peak PER2::LUC expression in the SCN and pituitary in both Six3syn and Vax1syn females. Interestingly, Six3syn ovaries presented reduced sensitivity to LH, causing reduced ovulation during superovulation. In conclusion, we have identified novel roles of the homeodomain transcription factors SIX3 and VAX1 in neurons, where they are required for proper molecular circadian clock function, SCN rhythmic output, and female fertility.
Collapse
Affiliation(s)
- Hanne M. Hoffmann
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, USA
| | - Jason D. Meadows
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Joseph A. Breuer
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Alexandra M. Yaw
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, USA
| | - Duong Nguyen
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, USA
| | - Karen J. Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Austin Y. Chin
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Brooke M. Devries
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, USA
| | - Crystal Trang
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Haley J. Oosterhouse
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Jessica Sora Lee
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| | - Jeffrey W. Doser
- CANR Statistical Consulting Center, Michigan State University, East Lansing, MI, USA
| | - Michael R. Gorman
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
- Department of Psychology, University of California, San Diego, La Jolla, CA, USA
| | - David K. Welsh
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
- Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Pamela L. Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA
| |
Collapse
|
9
|
Lavalle SN, Chou T, Hernandez J, Naing NCP, Tonsfeldt KJ, Hoffmann HM, Mellon PL. Kiss1 is differentially regulated in male and female mice by the homeodomain transcription factor VAX1. Mol Cell Endocrinol 2021; 534:111358. [PMID: 34098016 PMCID: PMC8319105 DOI: 10.1016/j.mce.2021.111358] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/13/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022]
Abstract
Regulation of Kiss1 transcription is crucial to the development and function of the reproductive axis. The homeodomain transcription factor, ventral anterior homeobox 1 (VAX1), has been implicated as a potential regulator of Kiss1 transcription. However, it is unknown whether VAX1 directly mediates transcription within kisspeptin neurons or works indirectly by acting upstream of kisspeptin neuron populations. This study tested the hypothesis that VAX1 within kisspeptin neurons regulates Kiss1 gene expression. We found that VAX1 acts as a repressor of Kiss1 in vitro and within the male arcuate nucleus in vivo. In female mice, we found that the loss of VAX1 caused a reduction in Kiss1 expression and Kiss1-containing neurons in the anteroventral periventricular nucleus at the time of the preovulatory luteinizing hormone surge, but was compensated by an increase in Kiss1-cFos colocalization. Despite changes in Kiss1 transcription, gonadotropin levels were unaffected and there were no impairments to fertility.
Collapse
Affiliation(s)
- Shanna N Lavalle
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Teresa Chou
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Jacqueline Hernandez
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Nay Chi P Naing
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Karen J Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Hanne M Hoffmann
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA; Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, 766 Service Road, East Lansing, MI, 48824, USA
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
10
|
Abstract
FSH is critical for fertility. Transcription of FSHB, the gene encoding the beta subunit, is rate-limiting in FSH production and is regulated by both GnRH and activin. Activin signals through SMAD transcription factors. Although the mechanisms and importance of activin signaling in mouse Fshb transcription are well-established, activin regulation of human FSHB is less well understood. We previously reported a novel enhancer of FSHB that contains a fertility-associated single nucleotide polymorphism (rs10031006) and requires a region resembling a full (8 base-pair) SMAD binding element (SBE). Here, we investigated the role of the putative SBE within the enhancer in activin and GnRH regulation of FSHB. In mouse gonadotrope-derived LβT2 cells, the upstream enhancer potentiated activin induction of both the human and mouse FSHB proximal promoters and conferred activin responsiveness to a minimal promoter. Activin induction of the enhancer required the SBE and was blocked by the inhibitory SMAD7, confirming involvement of the classical SMAD signaling pathway. GnRH induction of FSHB was also potentiated by the enhancer and dependent on the SBE, consistent with known activin/GnRH synergy regulating FSHB transcription. In DNA pull-down, the enhancer SBE bound SMAD4, and chromatin immunoprecipitation demonstrated SMAD4 enrichment at the enhancer in native chromatin. Combined activin/GnRH treatment elevated levels of the active transcriptional histone marker, histone 3 lysine 27 acetylation, at the enhancer. Overall, this study indicates that the enhancer is directly targeted by activin signaling and identifies a novel, evolutionarily conserved mechanism by which activin and GnRH can regulate FSHB transcription.
Collapse
Affiliation(s)
- Stephanie C Bohaczuk
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Jessica Cassin
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Theresa I Slaiwa
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Varykina G Thackray
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California 92093, USA
- Correspondence: Pamela L. Mellon, Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA. E-mail:
| |
Collapse
|
11
|
Ryan GE, Bohaczuk SC, Cassin J, Witham EA, Shojaei S, Ho EV, Thackray VG, Mellon PL. Androgen receptor positively regulates gonadotropin-releasing hormone receptor in pituitary gonadotropes. Mol Cell Endocrinol 2021; 530:111286. [PMID: 33872733 PMCID: PMC8177864 DOI: 10.1016/j.mce.2021.111286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/29/2021] [Accepted: 04/13/2021] [Indexed: 11/30/2022]
Abstract
Within pituitary gonadotropes, the gonadotropin-releasing hormone receptor (GnRHR) receives hypothalamic input from GnRH neurons that is critical for reproduction. Previous studies have suggested that androgens may regulate GnRHR, although the mechanisms remain unknown. In this study, we demonstrated that androgens positively regulate Gnrhr mRNA in mice. We then investigated the effects of androgens and androgen receptor (AR) on Gnrhr promoter activity in immortalized mouse LβT2 cells, which represent mature gonadotropes. We found that AR positively regulates the Gnrhr proximal promoter, and that this effect requires a hormone response element (HRE) half site at -159/-153 relative to the transcription start site. We also identified nonconsensus, full-length HREs at -499/-484 and -159/-144, which are both positively regulated by androgens on a heterologous promoter. Furthermore, AR associates with the Gnrhr promoter in ChIP. Altogether, we report that GnRHR is positively regulated by androgens through recruitment of AR to the Gnrhr proximal promoter.
Collapse
Affiliation(s)
- Genevieve E Ryan
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Stephanie C Bohaczuk
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Jessica Cassin
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Emily A Witham
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Shadi Shojaei
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Emily V Ho
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Varykina G Thackray
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
12
|
Devries BM, Breuer J, Yaw A, Jackson B, Nguyen D, Ho EV, Talluri T, Cui L, Gorman M, Sempere L, Mellon PL, Hoffmann HM. The Transcription Factor Ventral Anterior Homeobox 1 Modulates Circadian Time-Keeping and Fertility Through Direct Regulation of Vasoactive Intestinal Polypeptide Expression in the Suprachiasmatic Nucleus. J Endocr Soc 2021. [PMCID: PMC8265855 DOI: 10.1210/jendso/bvab048.1134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Light provides the primary timing signal that enables fine-tuned behavioral and hormonal entrainment of circadian rhythms to the environment. Light is transmitted from the eye to the brain through the retinohypothalamic tract, where one target is the hypothalamic suprachiasmatic nucleus (SCN), which generates self-sustained circadian rhythms. The vasoactive intestinal polypeptide (VIP) expressing neurons of the SCN relay light information to peripheral cells and tissues through control of hormonal and nervous signals, allowing synchronization of molecular clocks located in individual cells throughout the body. Non-natural light cycles, ie shiftwork, and weakened SCN function through genetic manipulation, disrupt the body’s circadian rhythms, causing deregulated hormone release, metabolic disorders, and negative effects on reproductive systems such as irregular menstrual cycles and decreased sperm count. To further our understanding of how the SCN translates light information into neuroendocrine control of fertility, we conditionally deleted the SCN enriched transcription factor Ventral anterior homeobox 1 (Vax1) in post-developmental VIP neurons, generating Vax1-flox/flox:Vip-Cre+ (cKO) mice. To determine if the SCN timekeeping function was impacted in cKO mice, we single housed males and females with running wheels to examine activity during both 12-hour light/dark cycles and in constant darkness. Wheel-running behavior in constant darkness revealed a shortening of the endogenous free-running period (Tau) of the SCN. Aside from Tau, wheel running behaviors were comparable to controls. Weakened SCN output can negatively impact fertility. While on 12-hour light/dark cycles, we found a modest, but significant change in follicle stimulating hormone and estrogen in cKO females and a reduced sensitivity of GnRH neurons to kisspeptin in males. The changes in hormone release were associated with a slightly lengthened estrous cycle in cKO females and reduced sperm quality in cKO males. To identify the molecular origin of the shortened SCN period, we used immunohistochemistry and RNAscope to examine expression of Vip. We found that diestrus cKO females had a significant reduction in Vip expression at ZT16 and preliminary data suggest a reduction in the circadian clock gene Bmal1. Together, these studies identify a novel role of VAX1 in VIP neurons where VAX1 is required for VIP expression and circadian timekeeping. Loss of VAX1 in VIP neurons weakens SCN output, deregulating reproductive hormone release and modestly reducing reproductive function in both males and females.
Collapse
|
13
|
Schoeller EL, Tonsfeldt KJ, Sinkovich M, Shi R, Mellon PL. Growth Hormone Pulses and Liver Gene Expression Are Differentially Regulated by the Circadian Clock Gene Bmal1. Endocrinology 2021; 162:6128829. [PMID: 33539533 PMCID: PMC7901660 DOI: 10.1210/endocr/bqab023] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Indexed: 12/16/2022]
Abstract
In this study, we found that loss of the circadian clock gene Bmal1 causes disruptions throughout the growth hormone (GH) axis, from hepatic gene expression to production of urinary pheromones and pheromone-dependent behavior. First, we show that Bmal1 knockout (KO) males elicit reduced aggressive responses from wild-type (WT) males and secrete lower levels of major urinary proteins (MUPs); however, we also found that a liver-specific KO of Bmal1 (liver-Bmal1-KO) produces a similar reduction in MUP secretion without a defect in aggressive behavior, indicating that the decrease in elicited aggression arises from another factor. We then shifted our investigation to determine the cause of MUP dysregulation in Bmal1 KO animals. Because the pulse pattern of GH drives sexually dimorphic expression of hepatic genes including MUPs, we examined GH pulsatility. We found that Bmal1 KO males have a female-like pattern of GH release, whereas liver-Bmal1-KO mice are not significantly different from either WT or Bmal1 KO. Since differential patterns of GH release regulate the transcription of many sexually dimorphic genes in the liver, we then examined hepatic gene transcription in Bmal1 KO and liver-Bmal1-KO mice. We found that while some female-predominant genes increase in the Bmal1 KO, there was no decrease in male-predominant genes, and little change in the liver-Bmal1-KO. We also found disrupted serum insulin growth factor 1 (IGF-1) and liver Igf1 messenger RNA in the Bmal1 KO mice, which may underlie the disrupted GH release. Overall, our findings differentiate between GH-pulse-driven and circadian-driven effects on hepatic genes, and the functional consequences of altered GH pulsatility.
Collapse
Affiliation(s)
- Erica L Schoeller
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
| | - Karen J Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
| | - McKenna Sinkovich
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
| | - Rujing Shi
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
- Correspondence: Pamela L. Mellon, PhD, Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0674, USA. )
| |
Collapse
|
14
|
Bohaczuk SC, Thackray VG, Shen J, Skowronska-Krawczyk D, Mellon PL. FSHB Transcription is Regulated by a Novel 5' Distal Enhancer With a Fertility-Associated Single Nucleotide Polymorphism. Endocrinology 2021; 162:5917511. [PMID: 33009549 PMCID: PMC7846141 DOI: 10.1210/endocr/bqaa181] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Indexed: 12/17/2022]
Abstract
The pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone, signal the gonads to regulate male and female fertility. FSH is critical for female fertility as it regulates oocyte maturation, ovulation, and hormone synthesis. Multiple genome-wide association studies (GWAS) link a 130 Kb locus at 11p14.1, which encompasses the FSH beta-subunit (FSHB) gene, with fertility-related traits that include polycystic ovary syndrome, age of natural menopause, and dizygotic twinning. The most statistically significant single nucleotide polymorphism from several GWAS studies (rs11031006) resides within a highly conserved 450 bp region 26 Kb upstream of the human FSHB gene. Given that sequence conservation suggests an important biological function, we hypothesized that the region could regulate FSHB transcription. In luciferase assays, the conserved region enhanced FSHB transcription and gel shifts identified a binding site for Steroidogenic factor 1 (SF1) contributing to its function. Analysis of mouse pituitary single-cell ATAC-seq demonstrated open chromatin at the conserved region exclusive to a gonadotrope cell-type cluster. Additionally, enhancer-associated histone markers were identified by immunoprecipitation of chromatin from mouse whole pituitary and an immortalized mouse gonadotrope-derived LβT2 cell line at the conserved region. Furthermore, we found that the rs11031006 minor allele upregulated FSHB transcription via increased SF1 binding to the enhancer. All together, these results identify a novel upstream regulator of FSHB transcription and indicate that rs11031006 can modulate FSH levels.
Collapse
Affiliation(s)
- Stephanie C Bohaczuk
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Varykina G Thackray
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Jia Shen
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, California
| | - Dorota Skowronska-Krawczyk
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, School of Medicine, University of California, San Diego, California
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, University of California Irvine, Irvine, California
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
- Correspondence: Pamela L. Mellon, Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA. E-mail:
| |
Collapse
|
15
|
Coré N, Erni A, Hoffmann HM, Mellon PL, Saurin AJ, Beclin C, Cremer H. Stem cell regionalization during olfactory bulb neurogenesis depends on regulatory interactions between Vax1 and Pax6. eLife 2020; 9:58215. [PMID: 32762844 PMCID: PMC7440913 DOI: 10.7554/elife.58215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/06/2020] [Indexed: 02/05/2023] Open
Abstract
Different subtypes of interneurons, destined for the olfactory bulb, are continuously generated by neural stem cells located in the ventricular and subventricular zones along the lateral forebrain ventricles of mice. Neuronal identity in the olfactory bulb depends on the existence of defined microdomains of pre-determined neural stem cells along the ventricle walls. The molecular mechanisms underlying positional identity of these neural stem cells are poorly understood. Here, we show that the transcription factor Vax1 controls the production of two specific neuronal subtypes. First, it is directly necessary to generate Calbindin expressing interneurons from ventro-lateral progenitors. Second, it represses the generation of dopaminergic neurons by dorsolateral progenitors through inhibition of Pax6 expression. We present data indicating that this repression occurs, at least in part, via activation of microRNA miR-7.
Collapse
Affiliation(s)
- Nathalie Coré
- Aix Marseille Univ, CNRS, IBDM, Campus de Luminy, Marseille, France
| | - Andrea Erni
- Aix Marseille Univ, CNRS, IBDM, Campus de Luminy, Marseille, France
| | - Hanne M Hoffmann
- Department of Obstetrics, Gynecology, and Reproductive Sciences and the Center for Reproductive Science and Medicine, University of California, San Diego, San Diego, United States
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences and the Center for Reproductive Science and Medicine, University of California, San Diego, San Diego, United States
| | - Andrew J Saurin
- Aix Marseille Univ, CNRS, IBDM, Campus de Luminy, Marseille, France
| | | | - Harold Cremer
- Aix Marseille Univ, CNRS, IBDM, Campus de Luminy, Marseille, France
| |
Collapse
|
16
|
Lavalle SN, Hernandez J, Mellon PL. OR16-01 The Expression of the Homeodomain Transcription Factor SIX3 within Kisspeptin Neurons Is Necessary for Reproduction in Mice. J Endocr Soc 2020. [PMCID: PMC7208320 DOI: 10.1210/jendso/bvaa046.965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The homeodomain transcription factor SIX3 is necessary for normal reproductive processes in mice. The loss of a single allele results in haploinsufficient phenotypes that are reflective of individuals with Kallmann Syndrome, such as hypogonadism, reduced GnRH neurons, and anosmia. Six3 heterozygous mice have reproductive impairments including an increased time to first litter, increased estrous cycle lengths in females, and fewer litters in males compared to wildtype controls. Prior studies found that deleting SIX3 specifically from GnRH neurons did not recapitulate the same phenotypes produced from a global knockout of the Six3 allele and imposed no reproductive abnormalities. This suggests that the role of SIX3 in reproduction is due to SIX3 populations outside of GnRH neurons. Using qPCR and RNA-seq, we have verified that Six3 is expressed in arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV) populations of kisspeptin neurons and can regulate the kisspeptin promoter in vitro. This led us to hypothesize that SIX3 in kisspeptin neurons is required for Kiss1 regulation and maximal fertility. We selectively deleted Six3 from kisspeptin neurons by crossing a Six3-floxed mouse with a Kiss1-Cre mouse to produce Six3 flox/flox; Kiss1-Cre positive mice (cKO) and Six3 flox/flox, Kiss-Cre negative littermates (controls). In female mice, we found that the loss of SIX3 from kisspeptin neurons disrupted the estrous cycle and reduced fertility. Compared to controls, cKO mice had fewer cycles in a 16-day period (0.38 vs 1.44; p=0.004; n=8-9), and spent a greater percentage of time in diestrus (80.5 vs 61.8; p=0.002; n=8-9) and a smaller percentage of time in estrus (15.6 vs 29.2; p=0.030; n=8-9). The loss of kisspeptin-specific SIX3 also resulted in reduced fecundity, with the cKO female mice having fewer pups within 90 days (15.0 vs 34.4; p=0.048; n=5-6) compared to controls. In addition to its importance in female mice, kisspeptin-specific SIX3 also plays a role in male fertility. We found that male cKO mice had reduced motile sperm (52.2% vs 72.5%; p=0.012; n=7-9) compared to controls. We also assayed levels of Kiss1 mRNA in the male arcuate nucleus and observed decreased Kiss1 levels compared to controls (0.34 vs 1.01; p=0.042; n=3-4). These results support our hypothesis that SIX3 in kisspeptin neurons is necessary for critical reproductive processes in both females and males, including progression through the estrous cycle, fecundity, and sperm motility, potentially through Kiss1 regulation.
Collapse
|
17
|
Ho EV, Shi C, Mellon PL. MON-039 Prenatal Anti-Mullerian Hormone (pAMH) Exposure in Mice Induces Changes in Pubertal Onset, Fertility, and Stress Response in Both Male and Female Offspring. J Endocr Soc 2020. [PMCID: PMC7207897 DOI: 10.1210/jendso/bvaa046.1317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility, classically presenting with disrupted ovulation, polycystic ovaries, and androgen excess, as well as many non-reproductive comorbidities. For instance, PCOS patients exhibit increased stress reactivity and higher rates of depression and anxiety compared to the general population. The prenatal anti-Mullerian hormone (pAMH)-induced model of PCOS was recently shown to recapitulate reproductive phenotypes in female mice, however little remains known about the consequences of pAMH exposure. We first aimed to expand upon this model by investigating pAMH-induced effects on offspring of both sexes. Pregnant dams on a C57Bl/6 background received daily i.p. injections of either AMH (0.12 mg/kg/d) or VEH late in gestation. Offspring were born into 4 groups (pAMH vs. VEH females, pAMH vs. VEH males) and assessed starting at weaning for changes in body weight, anogenital distance, pubertal onset, estrous cyclicity, fertility, and reproductive senescence. Statistical differences were determined by t-test or 2-way ANOVA when applicable, and significance set at p<0.05. As expected, pAMH increased anogenital distance in females but not males. Pubertal onset was delayed not only in females as previously reported, but also in males. Additionally, pAMH adult females showed significant disruptions in estrous cycling at P60 (increased time spent in diestrus, decreased number of cycles, increased cycle length), only mild disruptions by P90, then robust disruptions at 8 mo, 10 mo, and 12 mo of age that were distinct from reproductive senescence. When paired with wildtype untreated mates for a fertility assay starting at 3 mo of age, pAMH females had smaller and fewer number of litters, while pAMH males showed only delayed plugging behavior. Although pAMH males showed no difference in testis weight, pAMH females also had significantly reduced ovarian and uterine weights in diestrus. Interestingly, during the fertility assay, we found increased fetal death from both the pAMH females and males, even though pAMH males were paired with wildtype untreated females. We hypothesized that the increased fetal death could be the result of an pAMH-induced stress phenotype in both sexes. Using a simple stress response test measuring defecation and urination during exposure to a novel environment, we found that pAMH robustly increased stress response in both sexes at multiple timepoints. We also assessed glucocorticoid response to a restraint stress paradigm in adult females. While we observed no differences in baseline serum corticosterone levels, the pAMH group showed increased peak levels followed by a prolonged elevation levels after 2 hr. Together, these results enhance existing knowledge of the effects of pAMH exposure by demonstrating alterations in both male and female mice on both reproductive and non-reproductive measures.
Collapse
|
18
|
Nicholas D, Knight V, Tonsfeldt K, Terasaka T, Molinar-Inglis O, Stephens SBZ, Trejo J, Kauffman AS, Mellon PL, Lawson MA. MON-009 GLUT1-Mediated Glycolysis Facilitates GnRH-Induced Secretion of Luteinizing Hormone. J Endocr Soc 2020. [PMCID: PMC7208605 DOI: 10.1210/jendso/bvaa046.1694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Reproduction requires intensive energy expenditure, and energy availability impacts the function of the reproductive endocrine HPG-axis. Accordingly, the reproductive axis is suppressed during hypoglycemia. Circulating blood glucose can directly interact with gonadotropes within the highly vascular pituitary. Therefore, it is possible that gonadotropes may sense energy availability via the presence of glucose in the circulation and integrate this status with input from GnRH neurons to regulate hormone production. Gonadotropes dominantly express glucose transporter 1 (GLUT1) and increase glucose uptake in response to GnRH. Thus, we hypothesized that gonadotropes engage glycolysis in response to GnRH stimulation due to the high energy demand of protein synthesis required for LH production. We developed an approach to sort and successfully culture primary gonadotropes from wild type mice. Using this approach, we performed extracellular flux analysis and found that gonadotropes respond to GnRH by inducing GLUT1-mediated glycolysis that is independent of mitochondrial respiration. Knock-down of GLUT1 expression in the LβT2 gonadotrope cell line, glucose restriction, or treatment with the competitive inhibitor of glycolysis, 2-DG, diminished GnRH-induced LH secretion, indicating GLUT1 expression is necessary for maximal GnRH-induced LH secretion. We confirmed this observation in primary female mouse gonadotropes by limiting glucose availability which resulted in diminished basal LH and FSH secretion. Lastly, GLUT1 expression in the pituitary correlates with GnRH receptor expression and is increased during the LH surge in a mouse model. These results implicate glucose uptake through GLUT1 as permissive for gonadotrope secretion of LH and therefore reproductive function, especially the LH surge. We conclude that GLUT1-mediated glucose uptake is an important rate-limiting step in gonadotropin synthesis and operation of the HPG-axis.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Joann Trejo
- University of California San Diego, La Jolla, CA, USA
| | | | | | - Mark A Lawson
- University of California San Diego, La Jolla, CA, USA
| |
Collapse
|
19
|
Bohaczuk SC, Thackray VG, Mellon PL. OR24-05 Identifying Regulatory Elements Within a Novel Enhancer of FSHB Containing Two PCOS-Associated Single Nucleotide Polymorphisms. J Endocr Soc 2020. [PMCID: PMC7209709 DOI: 10.1210/jendso/bvaa046.749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polycystic ovary syndrome (PCOS) is the most common cause of female infertility, affecting approximately 10 percent of women by Rotterdam criteria, and is comorbid with obesity, type II diabetes, hypertension, and non-alcoholic fatty liver disease. As twin studies reveal that genetics account for approximately 70% of PCOS risk, genome-wide association studies (GWAS) can provide powerful insight into PCOS etiology. PCOS GWAS studies from several populations identified a risk locus containing the FSHB gene, which encodes the beta subunit of follicle-stimulating hormone (FSH). As FSH supplementation can restore ovulation in some PCOS patients, deficient FSH signaling could be a causative factor of anovulation and potentially other facets of PCOS. Two of the lead single nucleotide polymorphisms (SNPs) in association with PCOS, rs11031005 and rs11031006, fall within a highly conserved genomic region in mammals. We hypothesized that the conserved region (~450 base pairs) enhances FSHB transcription, and that one or both PCOS-related SNPs alter its function. We have shown that the conserved region from both human and mouse can act as an enhancer of FSHB in LβT2 cells, an immortalized, mouse-derived, mature pituitary gonadotrope cell line, and that its function is altered by the rs11031006 minor allele through modification of an SF1 consensus site. As elimination of the SF1 site reduced but did not completely abolish the function of the enhancer, we continued our investigation to identify additional regulatory sites. Transient transfection of LβT2 cells revealed a possible role for the rs11031005 SNP in FSHB regulation, with the minor allele decreasing enhancer-mediated FSHB transcription. This effect may be due to decreased binding of an unidentified transcription factor, as gel shift revealed that the rs11031005 minor allele reduced the intensity of a binding complex. Using truncations and sliding deletions, we identified three additional putative transcription factor binding sites with consensus sequences for ZEB1, PTX1, and SMAD. To support a role for the conserved region as an enhancer in native chromatin, we assessed the histone status in LβT2 chromatin. Compared to the proximal Fshb promoter, the enhancer-specific marker, H3K4me1, was enriched near the conserved region. Neither promoter/enhancer markers of active (H3K27Ac) or repressed (H3K27me3) chromatin were enriched near the conserved region, although levels of both modifications were consistent with the Fshb proximal promoter. Overall, our data support the role of this conserved region as a novel regulator of FSHB/Fshb transcription and reveal a possible mechanism to explain the contribution of PCOS-associated SNPs through FSHB regulation.
Collapse
|
20
|
Gou LT, Lim DH, Ma W, Aubol BE, Hao Y, Wang X, Zhao J, Liang Z, Shao C, Zhang X, Meng F, Li H, Zhang X, Xu R, Li D, Rosenfeld MG, Mellon PL, Adams JA, Liu MF, Fu XD. Initiation of Parental Genome Reprogramming in Fertilized Oocyte by Splicing Kinase SRPK1-Catalyzed Protamine Phosphorylation. Cell 2020; 180:1212-1227.e14. [PMID: 32169215 DOI: 10.1016/j.cell.2020.02.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/04/2019] [Accepted: 02/07/2020] [Indexed: 01/15/2023]
Abstract
The paternal genome undergoes a massive exchange of histone with protamine for compaction into sperm during spermiogenesis. Upon fertilization, this process is potently reversed, which is essential for parental genome reprogramming and subsequent activation; however, it remains poorly understood how this fundamental process is initiated and regulated. Here, we report that the previously characterized splicing kinase SRPK1 initiates this life-beginning event by catalyzing site-specific phosphorylation of protamine, thereby triggering protamine-to-histone exchange in the fertilized oocyte. Interestingly, protamine undergoes a DNA-dependent phase transition to gel-like condensates and SRPK1-mediated phosphorylation likely helps open up such structures to enhance protamine dismissal by nucleoplasmin (NPM2) and enable the recruitment of HIRA for H3.3 deposition. Remarkably, genome-wide assay for transposase-accessible chromatin sequencing (ATAC-seq) analysis reveals that selective chromatin accessibility in both sperm and MII oocytes is largely erased in early pronuclei in a protamine phosphorylation-dependent manner, suggesting that SRPK1-catalyzed phosphorylation initiates a highly synchronized reorganization program in both parental genomes.
Collapse
Affiliation(s)
- Lan-Tao Gou
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Do-Hwan Lim
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wubin Ma
- Howard Hughes Medical Institute, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brandon E Aubol
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yajing Hao
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xin Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences-University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jun Zhao
- Transgenic and Knockout Mouse Core, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zhengyu Liang
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Changwei Shao
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xuan Zhang
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Fan Meng
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hairi Li
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiaorong Zhang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ruiming Xu
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Dangsheng Li
- Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Pamela L Mellon
- Transgenic and Knockout Mouse Core, University of California, San Diego, La Jolla, CA 92093, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joseph A Adams
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mo-Fang Liu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences-University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
21
|
Pandolfi EC, Tonsfeldt KJ, Hoffmann HM, Mellon PL. Deletion of the Homeodomain Protein Six6 From GnRH Neurons Decreases GnRH Gene Expression, Resulting in Infertility. Endocrinology 2019; 160:2151-2164. [PMID: 31211355 PMCID: PMC6821215 DOI: 10.1210/en.2019-00113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/11/2019] [Indexed: 12/12/2022]
Abstract
Hypothalamic GnRH (luteinizing hormone-releasing hormone) neurons are crucial for the hypothalamic-pituitary-gonadal (HPG) axis, which regulates mammalian fertility. Insufficient GnRH disrupts the HPG axis and is often associated with the genetic condition idiopathic hypogonadotropic hypogonadism (IHH). The homeodomain protein sine oculis-related homeobox 6 (Six6) is required for the development of GnRH neurons. Although it is known that Six6 is specifically expressed within a more mature GnRH neuronal cell line and that overexpression of Six6 induces GnRH transcription in these cells, the direct role of Six6 within the GnRH neuron in vivo is unknown. Here we find that global Six6 knockout (KO) embryos show apoptosis of GnRH neurons beginning at embryonic day 14.5 with 90% loss of GnRH neurons by postnatal day 1. We sought to determine whether the hypogonadism and infertility reported in the Six6KO mice are generated via actions within the GnRH neuron in vivo by creating a Six6-flox mouse and crossing it with the LHRHcre mouse. Loss of Six6 specifically within the GnRH neuron abolished GnRH expression in ∼0% of GnRH neurons. We further demonstrated that deletion of Six6 only within the GnRH neuron leads to infertility, hypogonadism, hypogonadotropism, and delayed puberty. We conclude that Six6 plays distinct roles in maintaining fertility in the GnRH neuron vs in the migratory environment of the GnRH neuron by maintaining expression of GnRH and survival of GnRH neurons, respectively. These results increase knowledge of the role of Six6 in the brain and may offer insight into the mechanism of IHH.
Collapse
Affiliation(s)
- Erica C Pandolfi
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| | - Karen J Tonsfeldt
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| | - Hanne M Hoffmann
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
- Department of Animal Science, Michigan State University, East Lansing, Michigan
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| |
Collapse
|
22
|
Ruf-Zamojski F, Ge Y, Pincas H, Shan J, Song Y, Hines N, Kelley K, Montagna C, Nair P, Toufaily C, Bernard DJ, Mellon PL, Nair V, Turgeon JL, Sealfon SC. Cytogenetic, Genomic, and Functional Characterization of Pituitary Gonadotrope Cell Lines. J Endocr Soc 2019; 3:902-920. [PMID: 31020055 PMCID: PMC6469952 DOI: 10.1210/js.2019-00064] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 03/08/2019] [Indexed: 01/01/2023] Open
Abstract
LβT2 and αT3-1 are important, widely studied cell line models for the pituitary gonadotropes that were generated by targeted tumorigenesis in transgenic mice. LβT2 cells are more mature gonadotrope precursors than αT3-1 cells. Microsatellite authentication patterns, chromosomal characteristics, and their intercellular variation have not been reported. We performed microsatellite and cytogenetic analysis of both cell types at early passage numbers. Short tandem repeat (STR) profiling was consistent with a mixed C57BL/6J × BALB/cJ genetic background, with distinct patterns for each cell type. Spectral karyotyping in αT3-1 cells revealed cell-to-cell variation in chromosome composition and pseudodiploidy. In LβT2 cells, chromosome counting and karyotyping demonstrated pseudotriploidy and high chromosomal variation among cells. Chromosome copy number variation was confirmed by single-cell DNA sequencing. Chromosomal compositions were consistent with a male sex for αT3-1 and a female sex for LβT2 cells. Among LβT2 stocks used in multiple laboratories, we detected two genetically similar but distinguishable lines via STR authentication, LβT2a and LβT2b. The two lines differed in morphological appearance, with LβT2a having significantly smaller cell and nucleus areas. Analysis of immediate early gene and gonadotropin subunit gene expression revealed variations in basal expression and responses to continuous and pulsatile GnRH stimulation. LβT2a showed higher basal levels of Egr1, Fos, and Lhb but lower Fos induction. Fshb induction reached significance only in LβT2b cells. Our study highlights the heterogeneity in gonadotrope cell line genomes and provides reference STR authentication patterns that can be monitored to improve experimental reproducibility and facilitate comparisons of results within and across laboratories.
Collapse
Affiliation(s)
- Frederique Ruf-Zamojski
- Department of Neurology, Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Yongchao Ge
- Department of Neurology, Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Hanna Pincas
- Department of Neurology, Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jidong Shan
- Molecular Cytogenetic Core, Albert Einstein College of Medicine, New York, New York
| | - Yinghui Song
- Molecular Cytogenetic Core, Albert Einstein College of Medicine, New York, New York
| | - Nika Hines
- Mouse Genetics and Gene Targeting CoRE, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Kevin Kelley
- Mouse Genetics and Gene Targeting CoRE, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Cristina Montagna
- Molecular Cytogenetic Core, Albert Einstein College of Medicine, New York, New York
| | - Pranav Nair
- Department of Neurology, Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Chirine Toufaily
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Diego, La Jolla, California
| | - Venugopalan Nair
- Department of Neurology, Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Judith L Turgeon
- Department of Internal Medicine, University of California Davis, Davis, California
| | - Stuart C Sealfon
- Department of Neurology, Center for Advanced Research on Diagnostic Assays, Icahn School of Medicine at Mount Sinai, New York, New York
- Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| |
Collapse
|
23
|
Tonsfeldt KJ, Schoeller EL, Brusman LE, Cui LJ, Lee J, Mellon PL. The Contribution of the Circadian Gene Bmal1 to Female Fertility and the Generation of the Preovulatory Luteinizing Hormone Surge. J Endocr Soc 2019; 3:716-733. [PMID: 30906911 PMCID: PMC6425515 DOI: 10.1210/js.2018-00228] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 02/08/2019] [Indexed: 12/19/2022] Open
Abstract
In rodents, the preovulatory LH surge is temporally gated, but the timing cue is unknown. Estrogen primes neurons in the anteroventral periventricular nucleus (AVPV) to secrete kisspeptin, which potently activates GnRH neurons to release GnRH, eliciting a surge of LH to induce ovulation. Deletion of the circadian clock gene Bmal1 results in infertility. Previous studies have found that Bmal1 knockout (KO) females do not display an LH surge at any time of day. We sought to determine whether neuroendocrine disruption contributes to the absence of the LH surge. Because Kiss1 expression in the AVPV is critical for regulating ovulation, we hypothesized that this population is disrupted in Bmal1 KO females. However, we found an appropriate rise in AVPV Kiss1 and Fos mRNA at the time of lights out in ovariectomized estrogen-treated animals, despite the absence of a measureable increase in LH. Furthermore, Bmal1 KO females have significantly increased LH response to kiss-10 administration, although the LH response to GnRH was unchanged. We then created Kiss1- and GnRH-specific Bmal1 KO mice to examine whether Bmal1 expression is necessary within either kisspeptin or GnRH neurons. We detected no significant differences in any measured reproductive parameter. Our results indicate that disruption of the hypothalamic regulation of fertility in the Bmal1 KO females is not dependent on endogenous clocks within either the GnRH or kisspeptin neurons.
Collapse
Affiliation(s)
- Karen J Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Erica L Schoeller
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Liza E Brusman
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Laura J Cui
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Jinkwon Lee
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| |
Collapse
|
24
|
Hoffmann HM, Larder R, Lee JS, Hu RJ, Trang C, Devries BM, Clark DD, Mellon PL. Differential CRE Expression in Lhrh-cre and GnRH-cre Alleles and the Impact on Fertility in Otx2-Flox Mice. Neuroendocrinology 2019; 108:328-342. [PMID: 30739114 PMCID: PMC6753941 DOI: 10.1159/000497791] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 02/06/2019] [Indexed: 12/12/2022]
Abstract
There is an increasing trend in studies utilizing cell-specific deletion of genes through conditional gene deletion by CRE recombination. Despite numerous advantages, this strategy also has limitations such as ectopic CRE-expression and germline recombination. Two commonly used gonadotropin-releasing hormone (Gnrh)-driven CRE-expressing mice both target GnRH neurons. However, a direct comparison of the cells targeted and their phenotypic outcome have not yet been presented. To compare where recombination takes place, we crossed the Gnrh-cre and Lhrh-cre lines with the Rosa26-LacZ reporter mouse. Lhrh-cre allowed recombination of the Rosa26-LacZ gene in ∼700 cells, which is comparable to the GnRH neuronal population. Surprisingly, there were > 20 times more LacZ expressing cells in the adult Gnrh-cre:Rosa26-LacZ than the Lhrh-cre:Rosa26-LacZ brain. The greatest differences in targeting of the Gnrh-cre and Lhrh-cre lines were found in the septum, the suprachiasmatic nucleus, and the septohypothalamic area. This difference in cells targeted was present from embryonic day 12. A prior study using the Gnrh-cre to delete the transcription factor Otx2 found fewer GnRH neurons, leading to male and female subfertility. To recapitulate this study, we performed a fertility assay in Otx2:Lhrh-cre mice. We confirmed the requirement for Otx2 in GnRH neuron development, fertility and correct gonadotropin hormone release in Otx2:Lhrh-cre males, but the subfertility was more modest than in Otx2:Gnrh-cre and absent in female Otx2:Lhrh-cre. This suggests that ectopic expression of Gnrh-cre contributes to the reproductive phenotype observed. Finally, the Cre alleles caused germline recombination of the flox allele when transmitted from either parent, generating embryonic lethal knock-out offspring, producing smaller live litters.
Collapse
Affiliation(s)
- Hanne M Hoffmann
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Rachel Larder
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA
| | - Jessica S Lee
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA
| | - Rachael J Hu
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA
| | - Crystal Trang
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA
| | - Brooke M Devries
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Daniel D Clark
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA
| | - Pamela L Mellon
- Department of Obstetrics and Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, California, USA,
| |
Collapse
|
25
|
Pandolfi EC, Hoffmann HM, Schoeller EL, Gorman MR, Mellon PL. Haploinsufficiency of SIX3 Abolishes Male Reproductive Behavior Through Disrupted Olfactory Development, and Impairs Female Fertility Through Disrupted GnRH Neuron Migration. Mol Neurobiol 2018; 55:8709-8727. [PMID: 29589282 PMCID: PMC6156938 DOI: 10.1007/s12035-018-1013-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/16/2018] [Indexed: 12/17/2022]
Abstract
Mating behavior in males and females is dependent on olfactory cues processed through both the main olfactory epithelium (MOE) and the vomeronasal organ (VNO). Signaling through the MOE is critical for the initiation of male mating behavior, and the loss of MOE signaling severely compromises this comportment. Here, we demonstrate that dosage of the homeodomain gene Six3 affects the degree of development of MOE but not the VNO. Anomalous MOE development in Six3 heterozygote mice leads to hyposmia, specifically disrupting male mounting behavior by impairing detection of volatile female estrus pheromones. Six3 is highly expressed in the MOE, main olfactory bulb (MOB), and hypothalamus; all regions essential in the proper migration of the gonadotropin-releasing hormone (GnRH) neurons, a key reproductive neuronal population that migrates along olfactory axons from the developing nose into the brain. Interestingly, we find that the reduction in Six3 expression in Six3 heterozygote mice compromises development of the MOE and MOB, resulting in mis-migration of GnRH neurons due to improper olfactory axon targeting. This reduction in the hypothalamic GnRH neuron population, by 45% in adulthood, leads to female subfertility, but does not impact male hormone levels, suggesting that male infertility is not related to GnRH neuron numbers, but exclusively linked to abnormal olfaction. We here determine that Six3 is haploinsufficient for MOE development, GnRH neuron migration, and fertility, and represents a novel candidate gene for Kallmann syndrome, a form of inherited infertility.
Collapse
Affiliation(s)
- Erica C Pandolfi
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Hanne M Hoffmann
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Erica L Schoeller
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Michael R Gorman
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Psychology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Pamela L Mellon
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA.
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
26
|
Hoffmann HM, Pandolfi EC, Larder R, Mellon PL. Haploinsufficiency of Homeodomain Proteins Six3, Vax1, and Otx2 Causes Subfertility in Mice via Distinct Mechanisms. Neuroendocrinology 2018; 109:200-207. [PMID: 30261489 PMCID: PMC6437011 DOI: 10.1159/000494086] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 09/26/2018] [Indexed: 12/17/2022]
Abstract
Haploinsufficiency occurs when loss of one copy of a diploid gene (hemizygosity) causes a phenotype. It is relatively rare, in that most genes can produce sufficient mRNA and protein from a single copy to prevent any loss of normal activity and function. Reproduction is a complex process relying on migration of GnRH neurons from the olfactory placode to the hypothalamus during development. We have studied 3 different homeodomain genes Otx2, Vax1, and Six3 and found that the deletion of one allele for any of these genes in mice produces subfertility or infertility in one or both sexes, despite the presence of one intact allele. All 3 heterozygous mice have reduced numbers of GnRH neurons, but the mechanisms of subfertility differ significantly. This review compares the subfertility phenotypes and their mechanisms.
Collapse
Affiliation(s)
- Hanne M Hoffmann
- Department of Obstetrics, Gynecology, and Reproductive Sciences and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Erica C Pandolfi
- Department of Obstetrics, Gynecology, and Reproductive Sciences and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
| | - Rachel Larder
- Department of Obstetrics, Gynecology, and Reproductive Sciences and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California, USA,
| |
Collapse
|
27
|
Que X, Hung MY, Yeang C, Gonen A, Prohaska TA, Sun X, Diehl C, Määttä A, Gaddis DE, Bowden K, Pattison J, MacDonald JG, Ylä-Herttuala S, Mellon PL, Hedrick CC, Ley K, Miller YI, Glass CK, Peterson KL, Binder CJ, Tsimikas S, Witztum JL. Publisher Correction: Oxidized phospholipids are proinflammatory and proatherogenic in hypercholesterolaemic mice. Nature 2018; 561:E43. [PMID: 30013121 DOI: 10.1038/s41586-018-0313-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this Letter, affiliation number 1 was originally missing from the HTML; the affiliations were missing for author Ming-Yow Hung in the HTML; and the Fig. 4 legend erroneously referred to panels a-h, instead of a-g. These errors have been corrected online.
Collapse
Affiliation(s)
- Xuchu Que
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ming-Yow Hung
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei City, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Calvin Yeang
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ayelet Gonen
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Thomas A Prohaska
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xiaoli Sun
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Cody Diehl
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.,Brigham Young University Idaho, Rexburg, ID, USA
| | - Antti Määttä
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Dalia E Gaddis
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Karen Bowden
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jennifer Pattison
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | | | - Pamela L Mellon
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | - Klaus Ley
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Christopher K Glass
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Kirk L Peterson
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Christoph J Binder
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Sotirios Tsimikas
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Joseph L Witztum
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| |
Collapse
|
28
|
Que X, Hung MY, Yeang C, Gonen A, Prohaska TA, Sun X, Diehl C, Määttä A, Gaddis DE, Bowden K, Pattison J, MacDonald JG, Ylä-Herttuala S, Mellon PL, Hedrick CC, Ley K, Miller YI, Glass CK, Peterson KL, Binder CJ, Tsimikas S, Witztum JL. Oxidized phospholipids are proinflammatory and proatherogenic in hypercholesterolaemic mice. Nature 2018; 558:301-306. [PMID: 29875409 PMCID: PMC6033669 DOI: 10.1038/s41586-018-0198-8] [Citation(s) in RCA: 323] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 04/18/2018] [Indexed: 12/17/2022]
Abstract
Oxidized phospholipids (OxPL) are ubiquitous, are formed in many inflammatory tissues, including atherosclerotic lesions, and frequently mediate proinflammatory changes 1 . Because OxPL are mostly the products of non-enzymatic lipid peroxidation, mechanisms to specifically neutralize them are unavailable and their roles in vivo are largely unknown. We previously cloned the IgM natural antibody E06, which binds to the phosphocholine headgroup of OxPL, and blocks the uptake of oxidized low-density lipoprotein (OxLDL) by macrophages and inhibits the proinflammatory properties of OxPL2-4. Here, to determine the role of OxPL in vivo in the context of atherogenesis, we generated transgenic mice in the Ldlr-/- background that expressed a single-chain variable fragment of E06 (E06-scFv) using the Apoe promoter. E06-scFv was secreted into the plasma from the liver and macrophages, and achieved sufficient plasma levels to inhibit in vivo macrophage uptake of OxLDL and to prevent OxPL-induced inflammatory signalling. Compared to Ldlr-/- mice, Ldlr -/- E06-scFv mice had 57-28% less atherosclerosis after 4, 7 and even 12 months of 1% high-cholesterol diet. Echocardiographic and histologic evaluation of the aortic valves demonstrated that E06-scFv ameliorated the development of aortic valve gradients and decreased aortic valve calcification. Both cholesterol accumulation and in vivo uptake of OxLDL were decreased in peritoneal macrophages, and both peritoneal and aortic macrophages had a decreased inflammatory phenotype. Serum amyloid A was decreased by 32%, indicating decreased systemic inflammation, and hepatic steatosis and inflammation were also decreased. Finally, the E06-scFv prolonged life as measured over 15 months. Because the E06-scFv lacks the functional effects of an intact antibody other than the ability to bind OxPL and inhibit OxLDL uptake in macrophages, these data support a major proatherogenic role of OxLDL and demonstrate that OxPL are proinflammatory and proatherogenic, which E06 counteracts in vivo. These studies suggest that therapies inactivating OxPL may be beneficial for reducing generalized inflammation, including the progression of atherosclerosis, aortic stenosis and hepatic steatosis.
Collapse
Affiliation(s)
- Xuchu Que
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ming-Yow Hung
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei City, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Calvin Yeang
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ayelet Gonen
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Thomas A Prohaska
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xiaoli Sun
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Cody Diehl
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.,Brigham Young University Idaho, Rexburg, ID, USA
| | - Antti Määttä
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Dalia E Gaddis
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Karen Bowden
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jennifer Pattison
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | | | - Pamela L Mellon
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | - Klaus Ley
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Christopher K Glass
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Kirk L Peterson
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Christoph J Binder
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Sotirios Tsimikas
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Joseph L Witztum
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| |
Collapse
|
29
|
Ryan GE, Malik S, Mellon PL. Antiandrogen Treatment Ameliorates Reproductive and Metabolic Phenotypes in the Letrozole-Induced Mouse Model of PCOS. Endocrinology 2018; 159:1734-1747. [PMID: 29471436 PMCID: PMC6097580 DOI: 10.1210/en.2017-03218] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/03/2018] [Indexed: 12/31/2022]
Abstract
Polycystic ovary syndrome (PCOS), the most common endocrinopathy in women of reproductive age, is characterized by hyperandrogenism, anovulation, and polycystic ovaries. Although its etiology is unknown, excess androgens are thought to be a critical factor driving the pathology of PCOS. We previously demonstrated that continuous exposure to the aromatase inhibitor letrozole (LET) in mice produces many hallmarks of PCOS, including elevated testosterone (T) and luteinizing hormone, anovulation, and obesity. In the current study, we sought to determine whether androgen receptor (AR) actions are responsible for any of the phenotypes observed in LET mice. C57BL/6 female mice were subcutaneously implanted with LET or placebo control and subsequently treated with the nonsteroidal AR antagonist flutamide or vehicle control. Flutamide treatment in LET females reversed elevated T levels and restored ovarian expression of Cyp17a1 (critical for androgen synthesis) to normal levels. Pituitary expression of Lhb was decreased in LET females that received flutamide treatment, with no changes in expression of Fshb or Gnrhr. Flutamide treatment also restored estrous cycling and reduced the number of ovarian cyst-like follicles in LET females. Furthermore, body weight and adipocyte size were decreased in flutamide-treated LET females. Altogether, our findings provide strong evidence that AR signaling is responsible for many key reproductive and metabolic PCOS phenotypes and further establish the LET mouse model as an important tool for the study of androgen excess.
Collapse
Affiliation(s)
- Genevieve E Ryan
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| | - Shaddy Malik
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| | - Pamela L Mellon
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
- Correspondence: Pamela L. Mellon, PhD, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093. E-mail:
| |
Collapse
|
30
|
Hoffmann HM, Gong P, Tamrazian A, Mellon PL. Transcriptional interaction between cFOS and the homeodomain-binding transcription factor VAX1 on the GnRH promoter controls Gnrh1 expression levels in a GnRH neuron maturation specific manner. Mol Cell Endocrinol 2018; 461:143-154. [PMID: 28890143 PMCID: PMC5756504 DOI: 10.1016/j.mce.2017.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 08/23/2017] [Accepted: 09/05/2017] [Indexed: 12/18/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) is required for pubertal onset and reproduction, thus the control of GnRH transcription is tightly regulated during development and adulthood. GnRH neuron development depends on transcription factors of the homeodomain family. For example, Ventral anterior homeobox 1 (Vax1) is necessary to maintain GnRH expression after embryonic day 13 in the mouse. To further our understanding of the mechanisms by which VAX1 regulates GnRH gene expression, we asked whether VAX1 interacts with other transcription factors to modify GnRH expression levels. Using the GnRH cell lines, GN11 and GT1-7, we found that activation of PKC enhances expression of the immediate early gene cFos in both GN11, and GT1-7, and represses expression of Vax1 in GT1-7. Further, VAX1 interacts with cFOS while bound to the GnRH promoter. In immature GN11 cells, VAX1 and cFOS enhance GnRH expression, whereas VAX1 and cFOS have a repressive role in the mature GT1-7 cells.
Collapse
Affiliation(s)
- Hanne M Hoffmann
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Ping Gong
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Anika Tamrazian
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Pamela L Mellon
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
31
|
Xie H, Hoffmann HM, Iyer AK, Brayman MJ, Ngo C, Sunshine MJ, Mellon PL. Chromatin status and transcription factor binding to gonadotropin promoters in gonadotrope cell lines. Reprod Biol Endocrinol 2017; 15:86. [PMID: 29065928 PMCID: PMC5655979 DOI: 10.1186/s12958-017-0304-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 10/04/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Proper expression of key reproductive hormones from gonadotrope cells of the pituitary is required for pubertal onset and reproduction. To further our understanding of the molecular events taking place during embryonic development, leading to expression of the glycoproteins luteinizing hormone (LH) and follicle-stimulating hormone (FSH), we characterized chromatin structure changes, imparted mainly by histone modifications, in model gonadotrope cell lines. METHODS We evaluated chromatin status and gene expression profiles by chromatin immunoprecipitation assays, DNase sensitivity assay, and RNA sequencing in three developmentally staged gonadotrope cell lines, αT1-1 (progenitor, expressing Cga), αT3-1 (immature, expressing Cga and Gnrhr), and LβT2 (mature, expressing Cga, Gnrhr, Lhb, and Fshb), to assess changes in chromatin status and transcription factor access of gonadotrope-specific genes. RESULTS We found the common mRNA α-subunit of LH and FSH, called Cga, to have an open chromatin conformation in all three cell lines. In contrast, chromatin status of Gnrhr is open only in αT3-1 and LβT2 cells. Lhb begins to open in LβT2 cells and was further opened by activin treatment. Histone H3 modifications associated with active chromatin were high on Gnrhr in αT3-1 and LβT2, and Lhb in LβT2 cells, while H3 modifications associated with repressed chromatin were low on Gnrhr, Lhb, and Fshb in LβT2 cells. Finally, chromatin status correlates with the progressive access of LHX3 to Cga and Gnrhr, followed by PITX1 binding to the Lhb promoter. CONCLUSION Our data show the gonadotrope-specific genes Cga, Gnrhr, Lhb, and Fshb are not only controlled by developmental transcription factors, but also by epigenetic mechanisms that include the modulation of chromatin structure, and histone modifications.
Collapse
Affiliation(s)
- Huimin Xie
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
| | - Hanne M. Hoffmann
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
| | - Anita K. Iyer
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
- 0000 0004 0507 3954grid.185669.5Illumina Inc, 5200 Illumina Way, San Diego, CA 92122 USA
| | - Melissa J. Brayman
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
- Foley and Lardner LLP, 402 West Broadway, Suite 2100, San Diego, CA 92101 USA
| | - Cindy Ngo
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
| | - Mary Jean Sunshine
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
| | - Pamela L. Mellon
- 0000 0001 2107 4242grid.266100.3Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, 9500 Gilman Drive La Jolla, San Diego, CA 92093-0674 USA
| |
Collapse
|
32
|
Abstract
Circadian rhythms synchronize physiological processes with the light-dark cycle and are regulated by a hierarchical system initiated in the suprachiasmatic nucleus, a hypothalamic region that receives direct photic input. The suprachiasmatic nucleus then entrains additional oscillators in the periphery. Circadian rhythms are maintained by a molecular transcriptional feedback loop, of which brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) is a key member. Disruption of circadian rhythms by deletion of the BMAL1 gene (Bmal1 knockout [KO]) induces a variety of disease states, including infertility in males, due to unidentified mechanisms. We find that, despite normal sperm function, Bmal1 KO males fail to mate with receptive females, indicating a behavioral defect. Mating is dependent on pheromone detection, as are several other behaviors. We determined that Bmal1 KO males also fail to display aggression and avoidance of predator scent, despite intact main olfactory function. Moreover, the vomeronasal organ, a specialized pheromone-responsive organ, was also functionally intact, as determined by calcium imaging in response to urine pheromone stimulus. However, neural circuit tracing using c-FOS activation revealed that, although Bmal1 KO males displayed appropriate activation in the olfactory bulb and accessory olfactory bulb, the bed nucleus of the stria terminalis and the medial preoptic area (areas responsible for integration of copulatory behaviors) failed to activate highly in response to the female scent. This indicates that neural signaling in select behavioral centers is impaired in the absence of BMAL1, likely underlying Bmal1 KO male copulatory defects, demonstrating the importance of the BMAL1 protein in the maintenance of neural circuits that drive pheromone-mediated mating behaviors.
Collapse
Affiliation(s)
- Erica L Schoeller
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Daniel D Clark
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Sandeepa Dey
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Nathan V Cao
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Sheila J Semaan
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Ling W Chao
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Alexander S Kauffman
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Lisa Stowers
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| | - Pamela L Mellon
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (E.L.S., D.D.C., N.V.C., S.J.S., L.W.C., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; and Department of Molecular and Cellular Neuroscience (S.D., L.S.), The Scripps Research Institute, La Jolla, California 92037
| |
Collapse
|
33
|
Que X, Yeang C, Hung MY, Yamaguchi F, Diehl CJ, Gonen A, Prohaska TA, Wang S, Bowden K, Pattison J, Mellon PL, Gaddis D, Hedrick C, Ley K, Glass CK, Peterson KL, Binder CJ, Tsimikas S, Witztum JL. Abstract 361: Oxidized Phospholipids Are Proinflammatory and Proatherogenic. Arterioscler Thromb Vasc Biol 2016. [DOI: 10.1161/atvb.36.suppl_1.361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidized phospholipids (OxPL) are ubiquitously generated during inflammation, and found on apoptotic cells, OxLDL, and Lp(a). They facilitate uptake of OxLDL by macrophages (Mac) and mediate cellular inflammatory responses. The E06 natural IgM binds to the PC of OxPL, neutralizing biological effects and inhibiting OxLDL uptake by Mac. To determine the role of OxPL in atherogenesis, we generated transgenic mice expressing a single chain variant (scFv) of E06 in
Ldlr
background (E06-Tg). E06-scFv was secreted into plasma, bound to OxLDL and had sufficient titer to inhibit OxLDL uptake into Mac. E06-Tg or
Ldlr
mice were fed 1% Chol diet for 4, 7 or 12 months (n=12-15 mice/group). Plasma Chol was ~ 1600 mg/dL in all mice. Atherosclerosis decreased in E06-Tg mice:
En face
lesions decreased 57%, 34% and 28%, and aortic root lesions decreased 55%, 41% and 26% at 4, 7 and 12-months, respectively. OxLDL uptake by Macs was decreased: Thus, in E06-Tg mice, the uptake by peritoneal Mac of fluorescently-labeled OxLDL injected ip was decreased ~ 50%, as was peritoneal Mac Chol content. As Macs secrete E06-scFv, we performed BMT from E06-Tg donors into irradiated
Ldlr
recipients (n=10-12): This also decreased lesions 31% compared to BMT from control donors, even though plasma titers of E06-scFv were ~10% of Tg mice. Overexpression of E06-scFv was anti-inflammatory: Thus, in E06-Tg mice, both peritoneal and aortic wall resident macrophages exhibited decreased inflammatory gene expression, and phenotypic switches from M1 to M2 analyzed by RNAseq and FACS. Further, in E06-Tg mice, plasma SAA levels were reduced 32%, and hepatic steatosis was also decreased (-50% in both TG and Chol), as was hepatic inflammatory gene expression. Finally, E06-scFv attenuated both a progressive increase in aortic valve gradient (via echocardiography) and calcification in aged
Ldlr
mice. The E06-scFv lacks functional effects of an intact antibody other than the ability to “neutralize” OxPL. Thus, these data demonstrate that OxPL are profoundly proatherogenic and proinflammatory, which E06 counteracts
in vivo
. Neutralizing OxPL may therefore reduce the progression of atherosclerosis and cardiovascular events and more generally, represents a novel strategy to safely attenuate inflammation.
Collapse
Affiliation(s)
- Xuchu Que
- Medicine, Univ of California San Diego, La Jolla, CA
| | - Calvin Yeang
- Medicine, Univ of California San Diego, La Jolla, CA
| | - Ming-Yow Hung
- Medicine, Univ of California San Diego, La Jolla, CA
| | | | - Cody J Diehl
- Medicine, Univ of California San Diego, La Jolla, CA
| | - Ayelet Gonen
- Medicine, Univ of California San Diego, La Jolla, CA
| | | | - Shuling Wang
- Medicine, Univ of California San Diego, La Jolla, CA
| | - Karen Bowden
- Medicine, Univ of California San Diego, La Jolla, CA
| | | | - Pamela L Mellon
- Reproductive Medicine, Univ of California San Diego, La Jolla, CA
| | - Dalia Gaddis
- Div of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA
| | - Catherine Hedrick
- Div of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA
| | - Klaus Ley
- Div of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA
| | | | | | | | | | | |
Collapse
|
34
|
Hoffmann HM, Mellon PL. A small population of hypothalamic neurons govern fertility: the critical role of VAX1 in GnRH neuron development and fertility maintenance. Neurosci Commun (Houst) 2016; 2:e1373. [PMID: 28164172 PMCID: PMC5287408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fertility depends on the correct maturation and function of approximately 800 gonadotropin-releasing hormone (GnRH) neurons in the brain. GnRH neurons are at the apex of the hypothalamic-pituitary-gonadal axis that regulates fertility. In adulthood, GnRH neurons are scattered throughout the anterior hypothalamic area and project to the median eminence, where GnRH is released into the portal vasculature to stimulate release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary. LH and FSH then regulate gonadal steroidogenesis and gametogenesis. Absence of GnRH neurons or inappropriate GnRH release leads to infertility. Despite the critical role of GnRH neurons in fertility, we still have a limited understanding of the genes responsible for proper GnRH neuron development and function in adulthood. GnRH neurons originate in the olfactory placode then migrate into the brain. Homeodomain transcription factors expressed within GnRH neurons or along their migratory path are candidate genes for inherited infertility. Using a combined in vitro and in vivo approach, we have identified Ventral Anterior Homeobox 1 (Vax1) as a novel homeodomain transcription factor responsible for GnRH neuron maturation and fertility. GnRH neuron counts in Vax1 knock-out embryos revealed Vax1 to be required for the presence of GnRH-expressing cells at embryonic day 17.5 (E17.5), but not at E13.5. To localize the effects of Vax1 on fertility, we generated Vax1flox mice and crossed them with Gnrhcre mice to specifically delete Vax1 within GnRH neurons. GnRH staining in Vax1flox/flox:GnRHcre mice show a total absence of GnRH expression in the adult. We performed lineage tracing in Vax1flox/flox:GnRHcre:RosaLacZ mice which proved GnRH neurons to be alive, but incapable of expressing GnRH. The absence of GnRH leads to delayed puberty, hypogonadism and complete infertility in both sexes. Finally, using the immortalized model GnRH neuron cell lines, GN11 and GT1-7, we show that VAX1 is a direct regulator of Gnrh1 transcription by binding key ATTA sites within the Gnrh1 promoter. This study identifies VAX1 as a key transcription factor regulating GnRH expression and establishes VAX1 as a novel candidate gene implicated in heritable infertility.
Collapse
|
35
|
Skowronska-Krawczyk D, Zhao L, Zhu J, Weinreb RN, Cao G, Luo J, Flagg K, Patel S, Wen C, Krupa M, Luo H, Ouyang H, Lin D, Wang W, Li G, Xu Y, Li O, Chung C, Yeh E, Jafari M, Ai M, Zhong Z, Shi W, Zheng L, Krawczyk M, Chen D, Shi C, Zin C, Zhu J, Mellon PL, Gao W, Abagyan R, Zhang L, Sun X, Zhong S, Zhuo Y, Rosenfeld MG, Liu Y, Zhang K. P16INK4a Upregulation Mediated by SIX6 Defines Retinal Ganglion Cell Pathogenesis in Glaucoma. Mol Cell 2015; 59:931-40. [PMID: 26365380 DOI: 10.1016/j.molcel.2015.07.027] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 06/08/2015] [Accepted: 07/24/2015] [Indexed: 02/06/2023]
Abstract
Glaucoma, a blinding neurodegenerative disease, whose risk factors include elevated intraocular pressure (IOP), age, and genetics, is characterized by accelerated and progressive retinal ganglion cell (RGC) death. Despite decades of research, the mechanism of RGC death in glaucoma is still unknown. Here, we demonstrate that the genetic effect of the SIX6 risk variant (rs33912345, His141Asn) is enhanced by another major POAG risk gene, p16INK4a (cyclin-dependent kinase inhibitor 2A, isoform INK4a). We further show that the upregulation of homozygous SIX6 risk alleles (CC) leads to an increase in p16INK4a expression, with subsequent cellular senescence, as evidenced in a mouse model of elevated IOP and in human POAG eyes. Our data indicate that SIX6 and/or IOP promotes POAG by directly increasing p16INK4a expression, leading to RGC senescence in adult human retinas. Our study provides important insights linking genetic susceptibility to the underlying mechanism of RGC death and provides a unified theory of glaucoma pathogenesis.
Collapse
Affiliation(s)
- Dorota Skowronska-Krawczyk
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ling Zhao
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Jie Zhu
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Robert N Weinreb
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Guiqun Cao
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan 610041, China
| | - Jing Luo
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ken Flagg
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sherrina Patel
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cindy Wen
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Martin Krupa
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hongrong Luo
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hong Ouyang
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Danni Lin
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wenqiu Wang
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Ophthalmology, Shanghai First People's Hospital, School of Medicine, Shanghai JiaoTong University, Shanghai 20080, China
| | - Gen Li
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan 610041, China
| | - Yanxin Xu
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan 610041, China
| | - Oulan Li
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan 610041, China; Guangzhou KangRui Biological Pharmaceutical Technology Company Ltd., Guangzhou 510005, China
| | - Christopher Chung
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emily Yeh
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Maryam Jafari
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael Ai
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zheng Zhong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - William Shi
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lianghong Zheng
- Guangzhou KangRui Biological Pharmaceutical Technology Company Ltd., Guangzhou 510005, China
| | - Michal Krawczyk
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Daniel Chen
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Catherine Shi
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Carolyn Zin
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jin Zhu
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Pamela L Mellon
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Weiwei Gao
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ruben Abagyan
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Liangfang Zhang
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai First People's Hospital, School of Medicine, Shanghai JiaoTong University, Shanghai 20080, China
| | - Sheng Zhong
- Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yehong Zhuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
| | - Kang Zhang
- Shiley Eye Institute, Department of Ophthalmology and Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan 610041, China; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Veterans Administration Healthcare System, San Diego, CA 92093, USA.
| |
Collapse
|
36
|
Stephens SBZ, Tolson KP, Rouse ML, Poling MC, Hashimoto-Partyka MK, Mellon PL, Kauffman AS. Absent Progesterone Signaling in Kisspeptin Neurons Disrupts the LH Surge and Impairs Fertility in Female Mice. Endocrinology 2015; 156:3091-7. [PMID: 26076042 PMCID: PMC4541622 DOI: 10.1210/en.2015-1300] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Kisspeptin, encoded by Kiss1, stimulates GnRH neurons to govern reproduction. In rodents, estrogen-sensitive kisspeptin neurons in the anterior ventral periventricular nucleus and neighboring periventricular nucleus are thought to mediate sex steroid-induced positive feedback induction of the preovulatory LH surge. These kisspeptin neurons coexpress estrogen and progesterone receptors and display enhanced neuronal activation during the LH surge. However, although estrogen regulation of kisspeptin neurons has been well studied, the role of progesterone signaling in regulating kisspeptin neurons is unknown. Here we tested whether progesterone action specifically in kisspeptin cells is essential for proper LH surge and fertility. We used Cre-lox technology to generate transgenic mice lacking progesterone receptors exclusively in kisspeptin cells (termed KissPRKOs). Male KissPRKOs displayed normal fertility and gonadotropin levels. In stark contrast, female KissPRKOs displayed earlier puberty onset and significant impairments in fertility, evidenced by fewer births and substantially reduced litter size. KissPRKOs also had fewer ovarian corpora lutea, suggesting impaired ovulation. To ascertain whether this reflects a defect in the ability to generate sex steroid-induced LH surges, females were exposed to an estradiol-positive feedback paradigm. Unlike control females, which displayed robust LH surges, KissPRKO females did not generate notable LH surges and expressed significantly blunted cfos induction in anterior ventral periventricular nucleus kisspeptin neurons, indicating that progesterone receptor signaling in kisspeptin neurons is required for normal kisspeptin neuronal activation and LH surges during positive feedback. Our novel findings demonstrate that progesterone signaling specifically in kisspeptin cells is essential for the positive feedback induction of normal LH surges, ovulation, and normal fertility in females.
Collapse
Affiliation(s)
- Shannon B Z Stephens
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| | - Kristen P Tolson
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| | - Melvin L Rouse
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| | - Matthew C Poling
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| | - Minako K Hashimoto-Partyka
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| | - Pamela L Mellon
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| | - Alexander S Kauffman
- Department of Reproductive Medicine (S.B.Z.S., K.P.T., M.L.R., M.C.P., P.L.M., A.S.K.), University of California, San Diego, La Jolla, California 92093; and Department of Molecular, Cellular, and Developmental Biology (M.K.H.-P.), University of California, Los Angeles, Los Angeles, California 90095
| |
Collapse
|
37
|
Kauffman AS, Thackray VG, Ryan GE, Tolson KP, Glidewell-Kenney CA, Semaan SJ, Poling MC, Iwata N, Breen KM, Duleba AJ, Stener-Victorin E, Shimasaki S, Webster NJ, Mellon PL. A Novel Letrozole Model Recapitulates Both the Reproductive and Metabolic Phenotypes of Polycystic Ovary Syndrome in Female Mice. Biol Reprod 2015. [PMID: 26203175 DOI: 10.1095/biolreprod.115.131631] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Polycystic ovary syndrome (PCOS) pathophysiology is poorly understood, due partly to lack of PCOS animal models fully recapitulating this complex disorder. Recently, a PCOS rat model using letrozole (LET), a nonsteroidal aromatase inhibitor, mimicked multiple PCOS phenotypes, including metabolic features absent in other models. Given the advantages of using genetic and transgenic mouse models, we investigated whether LET produces a similar PCOS phenotype in mice. Pubertal female C57BL/6N mice were treated for 5 wk with LET, which resulted in increased serum testosterone and normal diestrus levels of estradiol, similar to the hyperandrogenemia and follicular phase estrogen levels of PCOS women. As in PCOS, ovaries from LET mice were larger, polycystic, and lacked corpora lutea versus controls. Most LET females were acyclic, and all were infertile. LET females displayed elevated serum LH levels and higher Lhb mRNA in the pituitary. In contrast, serum FSH and Fshb were significantly reduced in LET females, demonstrating differential effects on gonadotropins, as in PCOS. Within the ovary, LET females had higher Cyp17, Cyp19, and Fsh receptor mRNA expression. In the hypothalamus, LET females had higher kisspeptin receptor mRNA expression but lower progesterone receptor mRNA levels. LET females also gained more weight than controls, had increased abdominal adiposity and adipocyte size, elevated adipose inflammatory mRNA levels, and impaired glucose tolerance, mirroring the metabolic phenotype in PCOS women. This is the first report of a LET paradigm in mice that recapitulates both reproductive and metabolic PCOS phenotypes and will be useful to genetically probe the PCOS condition.
Collapse
Affiliation(s)
- Alexander S Kauffman
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Varykina G Thackray
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Genevieve E Ryan
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Kristen P Tolson
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Christine A Glidewell-Kenney
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Sheila J Semaan
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Matthew C Poling
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Nahoko Iwata
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Kellie M Breen
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Antoni J Duleba
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | | | - Shunichi Shimasaki
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| | - Nicholas J Webster
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Pamela L Mellon
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, California
| |
Collapse
|
38
|
Xie H, Hoffmann HM, Meadows JD, Mayo SL, Trang C, Leming SS, Maruggi C, Davis SW, Larder R, Mellon PL. Homeodomain Proteins SIX3 and SIX6 Regulate Gonadotrope-specific Genes During Pituitary Development. Mol Endocrinol 2015; 29:842-55. [PMID: 25915183 PMCID: PMC4447639 DOI: 10.1210/me.2014-1279] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 04/20/2015] [Indexed: 12/15/2022] Open
Abstract
Sine oculis-related homeobox 3 (SIX3) and SIX6, 2 closely related homeodomain transcription factors, are involved in development of the mammalian neuroendocrine system and mutations of Six6 adversely affect fertility in mice. We show that both small interfering RNA knockdown in gonadotrope cell lines and knockout of Six6 in both embryonic and adult male mice (Six6 knockout) support roles for SIX3 and SIX6 in transcriptional regulation in gonadotrope gene expression and that SIX3 and SIX6 can functionally compensate for each other. Six3 and Six6 expression patterns in gonadotrope cell lines reflect the timing of the expression of pituitary markers they regulate. Six3 is expressed in an immature gonadotrope cell line and represses transcription of the early lineage-specific pituitary genes, GnRH receptor (GnRHR) and the common α-subunit (Cga), whereas Six6 is expressed in a mature gonadotrope cell line and represses the specific β-subunits of LH and FSH (LHb and FSHb) that are expressed later in development. We show that SIX6 repression requires interaction with transducin-like enhancer of split corepressor proteins and competition for DNA-binding sites with the transcriptional activator pituitary homeobox 1. Our studies also suggest that estradiol and circadian rhythm regulate pituitary expression of Six6 and Six3 in adult females but not in males. In summary, SIX3 and SIX6 play distinct but compensatory roles in regulating transcription of gonadotrope-specific genes as gonadotrope cells differentiate.
Collapse
Affiliation(s)
- Huimin Xie
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Hanne M Hoffmann
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jason D Meadows
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Susan L Mayo
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Crystal Trang
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Sunamita S Leming
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Chiara Maruggi
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Shannon W Davis
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Rachel Larder
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| | - Pamela L Mellon
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.X., H.M.H., J.D.M., S.L.M., C.T., S.S.L., C.M., R.L., P.L.M.), University of California, San Diego, La Jolla, California 92093; and Department of Human Genetics (S.W.D.), University of Michigan, Ann Arbor, Michigan 48109
| |
Collapse
|
39
|
Ahow M, Min L, Pampillo M, Nash C, Wen J, Soltis K, Carroll RS, Glidewell-Kenney CA, Mellon PL, Bhattacharya M, Tobet SA, Kaiser UB, Babwah AV. KISS1R signals independently of Gαq/11 and triggers LH secretion via the β-arrestin pathway in the male mouse. Endocrinology 2014; 155:4433-46. [PMID: 25147978 PMCID: PMC4197989 DOI: 10.1210/en.2014-1304] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hypothalamic GnRH is the master regulator of the neuroendocrine reproductive axis, and its secretion is regulated by many factors. Among these is kisspeptin (Kp), a potent trigger of GnRH secretion. Kp signals via the Kp receptor (KISS1R), a Gαq/11-coupled 7-transmembrane-spanning receptor. Until this study, it was understood that KISS1R mediates GnRH secretion via the Gαq/11-coupled pathway in an ERK1/2-dependent manner. We recently demonstrated that KISS1R also signals independently of Gαq/11 via β-arrestin and that this pathway also mediates ERK1/2 activation. Because GnRH secretion is ERK1/2-dependent, we hypothesized that KISS1R regulates GnRH secretion via both the Gαq/11- and β-arrestin-coupled pathways. To test this hypothesis, we measured LH secretion, a surrogate marker of GnRH secretion, in mice lacking either β-arrestin-1 or β-arrestin-2. Results revealed that Kp-dependent LH secretion was significantly diminished relative to wild-type mice (P < .001), thus supporting that β-arrestin mediates Kp-induced GnRH secretion. Based on this, we hypothesized that Gαq/11-uncoupled KISS1R mutants, like L148S, will display Gαq/11-independent signaling. To test this hypothesis, L148S was expressed in HEK 293 cells. and results confirmed that, although strongly uncoupled from Gαq/11, L148S retained the ability to trigger significant Kp-dependent ERK1/2 phosphorylation (P < .05). Furthermore, using mouse embryonic fibroblasts lacking β-arrestin-1 and -2, we demonstrated that L148S-mediated ERK1/2 phosphorylation is β-arrestin-dependent. Overall, we conclude that KISS1R signals via Gαq/11 and β-arrestin to regulate GnRH secretion. This novel and important finding could explain why patients bearing some types of Gαq/11-uncoupled KISS1R mutants display partial gonadotropic deficiency and even a reversal of the condition, idiopathic hypogonadotropic hypogonadism.
Collapse
|
40
|
Glidewell-Kenney CA, Trang C, Shao PP, Gutierrez-Reed N, Uzo-Okereke AM, Coss D, Mellon PL. Neurokinin B induces c-fos transcription via protein kinase C and activation of serum response factor and Elk-1 in immortalized GnRH neurons. Endocrinology 2014; 155:3909-19. [PMID: 25057795 PMCID: PMC4164922 DOI: 10.1210/en.2014-1263] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations in neurokinin B (NKB) and its receptor, NK3R, were identified in human patients with hypogonadotropic hypogonadism, a disorder characterized by lack of puberty and infertility. Further studies have suggested that NKB acts at the level of the hypothalamus to control GnRH neuron activity, either directly or indirectly. We recently reported that treatment with senktide, a NK3R agonist, induced GnRH secretion and expression of c-fos mRNA in GT1-7 cells. Here, we map the responsive region in the murine c-fos promoter to between -400 and -200 bp, identify the signal transducer and activator of transcription (STAT) (-345) and serum response element (-310) sites as required for induction, a modulatory role for the Ets site (-318), and show that induction is protein kinase C dependent. Using gel shift and Gal4 assays, we further show that phosphorylation of Elk-1 leads to binding to DNA in complex with serum response factor at serum response element and Ets sites within the c-fos promoter. Thus, we determine molecular mechanisms involved in NKB regulation of c-fos induction, which may play a role in modulation of GnRH neuron activation.
Collapse
Affiliation(s)
- Christine A Glidewell-Kenney
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093-0674
| | | | | | | | | | | | | |
Collapse
|
41
|
Abstract
The known genetic causes of idiopathic hypogonadotropic hypogonadism (IHH) are often associated with the loss of GnRH neurons, leading to the disruption of the hypothalamic pituitary gonadal axis and subfertility. The majority of IHH cases have unknown origins and likely arise from compound mutations in more than one gene. Here we identify the homeodomain transcription factor ventral anterior homeobox1 (Vax1) as a potential genetic contributor to polygenic IHH. Although otherwise healthy, male and female Vax1 heterozygous (HET) mice are subfertile, indicating dosage sensitivity for the Vax1 allele. Although Vax1 mRNA is expressed in the pituitary, hypothalamus, and testis, we did not detect Vax1 mRNA in the sperm, ovary, or isolated pituitary gonadotropes. Whereas Vax1 HET females produced normal numbers of superovulated oocytes, corpora lutea numbers were reduced along with a slight increase in circulating basal LH and estrogen. The subfertility originated in the hypothalamus in which kisspeptin and GnRH transcripts were altered along with a substantial reduction of GnRH neuron number. Although the pituitary responded normally to a GnRH challenge, diestrus females had reduced LHβ and FSHβ in diestrus. Furthermore, Vax1 HET males had reduced GnRH mRNA and neuron numbers, whereas the pituitary had normal transcript levels and response to GnRH. Interestingly, the Vax1 HET males had an 88% reduction of motile sperm. Taken together, our data suggest that Vax1 HET subfertility originates in the hypothalamus by disrupting the hypothalamic-pituitary-gonadal axis. In addition, male subfertility may also be due to an unknown effect of Vax1 in the testis.
Collapse
Affiliation(s)
- Hanne M Hoffmann
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine (H.M.H., A.T., H.X., A.S.K., P.L.M.), University of California, San Diego, La Jolla, California 92093-0674; Department of Human Genetics (M.I.P.-M.), University of Michigan, Ann Arbor, Michigan 48109
| | | | | | | | | | | |
Collapse
|
42
|
Roybal LL, Hambarchyan A, Meadows JD, Barakat NH, Pepa PA, Breen KM, Mellon PL, Coss D. Roles of binding elements, FOXL2 domains, and interactions with cJUN and SMADs in regulation of FSHβ. Mol Endocrinol 2014; 28:1640-55. [PMID: 25105693 DOI: 10.1210/me.2014-1008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We previously identified FOXL2 as a critical component in FSHβ gene transcription. Here, we show that mice deficient in FOXL2 have lower levels of gonadotropin gene expression and fewer LH- and FSH-containing cells, but the same level of other pituitary hormones compared to wild-type littermates, highlighting a role of FOXL2 in the pituitary gonadotrope. Further, we investigate the function of FOXL2 in the gonadotrope cell and determine which domains of the FOXL2 protein are necessary for induction of FSHβ transcription. There is a stronger induction of FSHβ reporter transcription by truncated FOXL2 proteins, but no induction with the mutant lacking the forkhead domain. Specifically, FOXL2 plays a role in activin induction of FSHβ, functioning in concert with activin-induced SMAD proteins. Activin acts through multiple promoter elements to induce FSHβ expression, some of which bind FOXL2. Each of these FOXL2-binding sites is either juxtaposed or overlapping with a SMAD-binding element. We determined that FOXL2 and SMAD4 proteins form a higher order complex on the most proximal FOXL2 site. Surprisingly, two other sites important for activin induction bind neither SMADs nor FOXL2, suggesting additional factors at work. Furthermore, we show that FOXL2 plays a role in synergistic induction of FSHβ by GnRH and activin through interactions with the cJUN component of the AP1 complex that is necessary for GnRH responsiveness. Collectively, our results demonstrate the necessity of FOXL2 for proper FSH production in mice and implicate FOXL2 in integration of transcription factors at the level of the FSHβ promoter.
Collapse
Affiliation(s)
- Lacey L Roybal
- Department of Reproductive Medicine (L.L.R., A.H., J.D.M., P.A.P., K.M.B., P.L.M., D.C.), Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093-0674; Division of Biomedical Sciences (N.H.B., D.C.), School of Medicine, University of California, Riverside; Riverside, California 92521
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Breen KM, Mellon PL. Influence of stress-induced intermediates on gonadotropin gene expression in gonadotrope cells. Mol Cell Endocrinol 2014; 385:71-7. [PMID: 24012628 PMCID: PMC3942370 DOI: 10.1016/j.mce.2013.08.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/14/2013] [Accepted: 08/21/2013] [Indexed: 11/20/2022]
Abstract
Despite extensive investigation, a comprehensive understanding of the mechanisms whereby stress impacts fertility remains elusive. Since the 1930s, when Hans Selye popularized studying adaptations to stress (Selye, 1937), we have learned that compensatory mechanisms involve a complex interplay of neural and hormonal processes that allow various body functions to adjust to stress, in a coordinated manner. In terms of reproduction, the adjustment to a stressor interferes with integrated functioning at multiple levels of regulation--the hypothalamus, anterior pituitary gland, gonads, and neural centers coordinating behavior. Various mediators are postulated to participate in reproductive suppression. These include catecholamines, cytokines, prostaglandins, endogenous opioid peptides, and hormones of the hypothalamic-pituitary-adrenal axis. This review focuses on one class of mediators, the glucocorticoids, and provides our views on the relevance and mode of action of this inhibitory intermediate within the anterior pituitary gonadotrope, as a potential cellular site whereby glucocorticoids contribute to stress-induced reproductive suppression.
Collapse
Affiliation(s)
- Kellie M Breen
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674, United States.
| | - Pamela L Mellon
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674, United States
| |
Collapse
|
44
|
Clark DD, Gorman MR, Hatori M, Meadows JD, Panda S, Mellon PL. Aberrant development of the suprachiasmatic nucleus and circadian rhythms in mice lacking the homeodomain protein Six6. J Biol Rhythms 2013; 28:15-25. [PMID: 23382588 DOI: 10.1177/0748730412468084] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The suprachiasmatic nucleus (SCN) of the mammalian hypothalamus is the central pacemaker for peripheral and organismal circadian rhythms. The development of this hypothalamic structure depends on genetic programs throughout embryogenesis. We have investigated the role of the homeodomain transcription factor Six6 in the development of the SCN. We first showed that Six6 mRNA has circadian regulation in the mouse SCN. We then characterized the behavioral activity patterns of Six6-null mice under various photoperiod manipulations and stained their hypothalami using SCN-specific markers. Six6-null mice display abnormal patterns of circadian behavior indicative of SCN abnormalities. The ability of light exposure to reset rhythms correlates with the presence or absence of optic nerves, but all Six6-null mice show irregular rhythms. In contrast, wild-type mice with crushed optic nerves maintain regular rhythms regardless of light exposure. Using immunohistochemistry for arginine vasopressin (AVP), vasoactive intestinal polypeptide (VIP), and β-galactosidase, we demonstrated the lack of these SCN markers in all Six6-null mice regardless of the presence of optic nerve or partial circadian rhythms. Therefore, Six6 is required for the normal development of the SCN, and the Six6-null mouse can mount independent, although irregular, circadian rhythms despite the apparent absence of a histochemically defined SCN.
Collapse
Affiliation(s)
- Daniel D Clark
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | | | | | | | | |
Collapse
|
45
|
Larder R, Kimura I, Meadows J, Clark DD, Mayo S, Mellon PL. Gene dosage of Otx2 is important for fertility in male mice. Mol Cell Endocrinol 2013; 377:16-22. [PMID: 23811236 PMCID: PMC3771655 DOI: 10.1016/j.mce.2013.06.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 06/18/2013] [Accepted: 06/19/2013] [Indexed: 02/07/2023]
Abstract
Together, the hypothalamus, pituitary and gonads direct the development and regulation of reproductive function in mammals. Gonadotropin-releasing hormone (GnRH) expression is limited to ∼800 neurons that originate in the olfactory placode then migrate to the hypothalamus. Coordination of the hypothalamic-pituitary-gonadal (HPG) axis is dependent upon correct neuronal migration of GnRH neurons into the hypothalamus followed by proper synthesis and pulsatile secretion of GnRH. Defects in any one of these processes causes infertility. Otx2, the vertebrate homologue of Drosophila orthodenticle, is a transcription factor that has been shown to be critical for normal brain and eye development and is expressed in both the developing GnRH neurons and the pituitary, suggesting that this gene may play a critical role in development of the HPG axis. As Otx2-null mice are embryonic lethal, we have analyzed the reproductive capacity of heterozygous Otx2 mice to determine the contribution of Otx2 gene dosage to normal HPG axis function. Our data reveal that correct dosage of Otx2 is critical for normal fertility as loss of one allele of Otx2 leads to a discernible reproductive phenotype in male mice due to disruption of the migration of GnRH neurons during development.
Collapse
Affiliation(s)
- Rachel Larder
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
| | - Ikuo Kimura
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
- Department of Genomic Drug Discovery Science, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo-ku, Kyoto 606-8501, Japan
| | - Jason Meadows
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
| | - Daniel. D. Clark
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
| | - Susan Mayo
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
| | - Pamela L. Mellon
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
- To whom correspondence should be addressed, , Telephone: 1-858-534-1312, Fax: 1-858-534-1438
| |
Collapse
|
46
|
Witham EA, Meadows JD, Hoffmann HM, Shojaei S, Coss D, Kauffman AS, Mellon PL. Kisspeptin regulates gonadotropin genes via immediate early gene induction in pituitary gonadotropes. Mol Endocrinol 2013; 27:1283-94. [PMID: 23770611 DOI: 10.1210/me.2012-1405] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Kisspeptin signaling through its receptor, Kiss1R, is crucial for many reproductive functions including puberty, sex steroid feedback, and overall fertility. Although the importance of Kiss1R in the brain is firmly established, its role in regulating reproduction at the level of the pituitary is not well understood. This study presents molecular analysis of the role of kisspeptin and Kiss1R signaling in the transcriptional regulation of the gonadotropin gene β-subunits, LHβ and FSHβ, using LβT2 gonadotrope cells and murine primary pituitary cells. We show that kisspeptin induces LHβ and FSHβ gene expression, and this induction is protein kinase C dependent and mediated by the immediate early genes, early growth response factor 1 and cFos, respectively. Additionally, kisspeptin induces transcription of the early growth response factor 1 and cFos promoters in LβT2 cells. Kisspeptin also increases gonadotropin gene expression in mouse primary pituitary cells in culture. Furthermore, we find that Kiss1r expression is enhanced in the pituitary of female mice during the estradiol-induced LH surge, a critical component of the reproductive cycle. Overall, our findings indicate that kisspeptin regulates gonadotropin gene expression through the activation of Kiss1R signaling through protein kinase C, inducing immediate early genes in vitro, and responds to physiologically relevant cues in vivo, suggesting that kisspeptin affects pituitary gene expression to regulate reproductive function.
Collapse
Affiliation(s)
- Emily A Witham
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093-0674, USA
| | | | | | | | | | | | | |
Collapse
|
47
|
Glidewell-Kenney CA, Shao PP, Iyer AK, Grove AMH, Meadows JD, Mellon PL. Neurokinin B causes acute GnRH secretion and repression of GnRH transcription in GT1-7 GnRH neurons. Mol Endocrinol 2013; 27:437-54. [PMID: 23393128 DOI: 10.1210/me.2012-1271] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Genetic studies in human patients with idiopathic hypogonadotropic hypogonadism (IHH) identified mutations in the genes that encode neurokinin B (NKB) and the neurokinin 3 receptor (NK3R). However, determining the mechanism whereby NKB regulates gonadotropin secretion has been difficult because of conflicting results from in vivo studies investigating the luteinizing hormone (LH) response to senktide, a NK3R agonist. NK3R is expressed in a subset of GnRH neurons and in kisspeptin neurons that are known to regulate GnRH secretion. Thus, one potential source of inconsistency is that NKB could produce opposing direct and indirect effects on GnRH secretion. Here, we employ the GT1-7 cell model to elucidate the direct effects of NKB on GnRH neuron function. We find that GT1-7 cells express NK3R and respond to acute senktide treatment with c-Fos induction and increased GnRH secretion. In contrast, long-term senktide treatment decreased GnRH secretion. Next, we focus on the examination of the mechanism underlying the long-term decrease in secretion and determine that senktide treatment represses transcription of GnRH. We further show that this repression of GnRH transcription may involve enhanced c-Fos protein binding at novel activator protein-1 (AP-1) half-sites identified in enhancer 1 and the promoter, as well as chromatin remodeling at the promoter of the GnRH gene. These data indicate that NKB could directly regulate secretion from NK3R-expressing GnRH neurons. Furthermore, whether the response is inhibitory or stimulatory toward GnRH secretion could depend on the history or length of exposure to NKB because of a repressive effect on GnRH transcription.
Collapse
Affiliation(s)
- Christine A Glidewell-Kenney
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093-0674, USA
| | | | | | | | | | | |
Collapse
|
48
|
Xie H, Cherrington BD, Meadows JD, Witham EA, Mellon PL. Msx1 homeodomain protein represses the αGSU and GnRH receptor genes during gonadotrope development. Mol Endocrinol 2013; 27:422-36. [PMID: 23371388 DOI: 10.1210/me.2012-1289] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Multiple homeodomain transcription factors are crucial for pituitary organogenesis and cellular differentiation. A homeodomain repressor, Msx1, is expressed from the ventral aspect of the developing anterior pituitary and implicated in gonadotrope differentiation. Here, we find that Msx1 represses transcription of lineage-specific pituitary genes such as the common α-glycoprotein subunit (αGSU) and GnRH receptor (GnRHR) promoters in the mouse gonadotrope-derived cell lines, αT3-1 and LβT2. Repression of the mouse GnRHR promoter by Msx1 is mediated through a consensus-binding motif in the downstream activin regulatory element (DARE). Truncation and mutation analyses of the human αGSU promoter map Msx1 repression to a site at -114, located at the junctional regulatory element (JRE). Dlx activators are closely related to the Msx repressors, acting through the same elements, and Dlx3 and Dlx2 act as transcriptional activators for GnRHR and αGSU, respectively. Small interfering RNA knockdown of Msx1 in αT3-1 cells increases endogenous αGSU and GnRHR mRNA expression. Msx1 gene expression reaches its maximal expression at the rostral edge at e13.5. The subsequent decline in Msx1 expression specifically coincides with the onset of expression of both αGSU and GnRHR. The expression levels of both αGSU and GnRHR in Msx1-null mice at e18.5 are higher compared with wild type, further confirming a role for Msx1 in the repression of αGSU and GnRHR. In summary, Msx1 functions as a negative regulator early in pituitary development by repressing the gonadotrope-specific αGSU and GnRHR genes, but a temporal decline in Msx1 expression alleviates this repression allowing induction of GnRHR and αGSU, thus serving to time the onset of gonadotrope-specific gene program.
Collapse
Affiliation(s)
- Huimin Xie
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA 92093-0674, USA
| | | | | | | | | |
Collapse
|
49
|
Brayman MJ, Pepa PA, Mellon PL. Androgen receptor repression of gonadotropin-releasing hormone gene transcription via enhancer 1. Mol Cell Endocrinol 2012; 363:92-9. [PMID: 22877652 PMCID: PMC3447085 DOI: 10.1016/j.mce.2012.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 07/25/2012] [Accepted: 07/26/2012] [Indexed: 01/27/2023]
Abstract
Gonadotropin-releasing hormone (GnRH) plays a major role in the hypothalamic-pituitary-gonadal (HPG) axis, and synthesis and secretion of GnRH are regulated by gonadal steroid hormones. Disruptions in androgen levels are involved in a number of reproductive defects, including hypogonadotropic hypogonadism and polycystic ovarian syndrome. Androgens down-regulate GnRH mRNA synthesis in vivo and in vitro via an androgen receptor (AR)-dependent mechanism. Methyltrienolone (R1881), a synthetic AR agonist, represses GnRH expression through multiple sites in the proximal promoter. In this study, we show AR also represses GnRH transcription via the major enhancer (GnRH-E1). A multimer of the -1800/-1766 region was repressed by R1881 treatment. Mutation of two bases, -1792 and -1791, resulted in decreased basal activity and a loss of AR-mediated repression. AR bound to the -1796/-1791 sequence in electrophoretic mobility shift assays, indicating a direct interaction with DNA or other transcription factors in this region. We conclude that AR repression of GnRH-E1 acts via multiple AR-responsive regions, including the site at -1792/-1791.
Collapse
Affiliation(s)
- Melissa J Brayman
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093-0674, USA
| | | | | |
Collapse
|
50
|
Witham EA, Meadows JD, Shojaei S, Kauffman AS, Mellon PL. Prenatal exposure to low levels of androgen accelerates female puberty onset and reproductive senescence in mice. Endocrinology 2012; 153:4522-32. [PMID: 22778229 PMCID: PMC3423623 DOI: 10.1210/en.2012-1283] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sex steroid hormone production and feedback mechanisms are critical components of the hypothalamic-pituitary-gonadal (HPG) axis and regulate fetal development, puberty, fertility, and menopause. In female mammals, developmental exposure to excess androgens alters the development of the HPG axis and has pathophysiological effects on adult reproductive function. This study presents an in-depth reproductive analysis of a murine model of prenatal androgenization (PNA) in which females are exposed to a low dose of dihydrotestosterone during late prenatal development on embryonic d 16.5-18.5. We determined that PNA females had advanced pubertal onset and a delay in the time to first litter, compared with vehicle-treated controls. The PNA mice also had elevated testosterone, irregular estrous cyclicity, and advanced reproductive senescence. To assess the importance of the window of androgen exposure, dihydrotestosterone was administered to a separate cohort of female mice on postnatal d 21-23 [prepubertal androgenization (PPA)]. PPA significantly advanced the timing of pubertal onset, as observed by age of the vaginal opening, yet had no effects on testosterone or estrous cycling in adulthood. The absence of kisspeptin receptor in Kiss1r-null mice did not change the acceleration of puberty by the PNA and PPA paradigms, indicating that kisspeptin signaling is not required for androgens to advance puberty. Thus, prenatal, but not prepubertal, exposure to low levels of androgens disrupts normal reproductive function throughout life from puberty to reproductive senescence.
Collapse
Affiliation(s)
- Emily A Witham
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | | | | | | |
Collapse
|