1
|
Gu Z, Yang J, Yang M, Deng Y, Jiao Y. Immunomodulatory effects of decitabine in pearl oyster Pinctada fucata martensii. FISH & SHELLFISH IMMUNOLOGY 2022; 129:191-198. [PMID: 36029945 DOI: 10.1016/j.fsi.2022.08.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Decitabine (DAC), an inhibitor of DNA methyltransferase, is typically used to reverse DNA methylation and is considered an epigenetic modifying drug. DNA methylation is crucial to the regulation of gene expression without altering genetic information. Our previous research showed that the DNA methylation levels of many immune-related genes changed after the pre-grafting condition in pearl production. In the present study, we evaluated the DNA methylation level and analyzed transcriptome, enzyme, and antimicrobial activities after DAC treatment to evaluate the effect of DAC on DNA methylation and immune system of pearl oyster Pinctada fucata martensii. Results showed that DAC significantly decreased the level of global DNA methylation in the hemocytes of the pearl oysters. Transcriptome analysis obtained 577 differentially expressed genes (DEGs) between the control and DAC treatment group. The DEGs were mainly enriched in the following pathways: "Relaxin signaling pathway," "Cytosolic DNA-sensing pathway," "Platelet activation," and "Peroxisome," and related genes were overexpressed after DAC treatment. DAC treatment resulted in a substantial increase in the levels of serum superoxide dismutase, interleukin-17, phenol oxidase, tumor necrosis factor, and antimicrobial activity, compared with the control. These results suggested that DAC can alter DNA methylation level, activate immune-related genes, and improve the level of humoral immunity in pearl oysters, thereby increasing our understanding of the mechanism underlying DNA methylation in immune regulation.
Collapse
Affiliation(s)
- Zefeng Gu
- Fishery College, Guangdong Ocean University, Zhanjiang, 524025, China
| | - Jingmiao Yang
- Fishery College, Guangdong Ocean University, Zhanjiang, 524025, China
| | - Min Yang
- Fishery College, Guangdong Ocean University, Zhanjiang, 524025, China
| | - Yuewen Deng
- Fishery College, Guangdong Ocean University, Zhanjiang, 524025, China; Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang, 524088, China; Guangdong Science and Innovation Center for Pearl Culture, Zhanjiang, 524088, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Zhanjiang, 524088, China
| | - Yu Jiao
- Fishery College, Guangdong Ocean University, Zhanjiang, 524025, China; Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang, 524088, China; Guangdong Science and Innovation Center for Pearl Culture, Zhanjiang, 524088, China.
| |
Collapse
|
2
|
Mills EG, Yang L, Nielsen MF, Kassem M, Dhillo WS, Comninos AN. The Relationship Between Bone and Reproductive Hormones Beyond Estrogens and Androgens. Endocr Rev 2021; 42:691-719. [PMID: 33901271 PMCID: PMC8599211 DOI: 10.1210/endrev/bnab015] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Indexed: 12/20/2022]
Abstract
Reproductive hormones play a crucial role in the growth and maintenance of the mammalian skeleton. Indeed, the biological significance for this hormonal regulation of skeletal homeostasis is best illustrated by common clinical reproductive disorders, such as primary ovarian insufficiency, hypothalamic amenorrhea, congenital hypogonadotropic hypogonadism, and early menopause, which contribute to the clinical burden of low bone mineral density and increased risk for fragility fracture. Emerging evidence relating to traditional reproductive hormones and the recent discovery of newer reproductive neuropeptides and hormones has deepened our understanding of the interaction between bone and the reproductive system. In this review, we provide a contemporary summary of the literature examining the relationship between bone biology and reproductive signals that extend beyond estrogens and androgens, and include kisspeptin, gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, progesterone, inhibin, activin, and relaxin. A comprehensive and up-to-date review of the recent basic and clinical research advances is essential given the prevalence of clinical reproductive disorders, the emerging roles of upstream reproductive hormones in bone physiology, as well as the urgent need to develop novel safe and effective therapies for bone fragility in a rapidly aging population.
Collapse
Affiliation(s)
- Edouard G Mills
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Lisa Yang
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Morten F Nielsen
- Department of Endocrinology, University Hospital of Odense & institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark
| | - Moustapha Kassem
- Department of Endocrinology, University Hospital of Odense & institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark.,Faculty of Health and Medical Sciences, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Waljit S Dhillo
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK.,Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK
| | - Alexander N Comninos
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK.,Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK.,Endocrine Bone Unit, Imperial College Healthcare NHS Trust, London, UK
| |
Collapse
|
3
|
Injamuri S, Rahaman MN, Shen Y, Huang Y. Relaxin enhances bone regeneration with BMP‐2‐loaded hydroxyapatite microspheres. J Biomed Mater Res A 2020; 108:1231-1242. [DOI: 10.1002/jbm.a.36897] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 01/21/2020] [Accepted: 02/04/2020] [Indexed: 01/11/2023]
Affiliation(s)
- Sahitya Injamuri
- Department of Biological SciencesMissouri University of Science and Technology Rolla Missouri
| | - Mohamed N. Rahaman
- Department of Materials Science and EngineeringMissouri University of Science and Technology Rolla Missouri
| | - Youqu Shen
- Department of Materials Science and EngineeringMissouri University of Science and Technology Rolla Missouri
| | - Yue‐Wern Huang
- Department of Biological SciencesMissouri University of Science and Technology Rolla Missouri
| |
Collapse
|
4
|
Kamimoto H, Kobayashi Y, Moriyama K. Relaxin 2 carried by magnetically directed liposomes accelerates rat midpalatal suture expansion and subsequent new bone formation. Bone Rep 2019; 10:100202. [PMID: 30937342 PMCID: PMC6430079 DOI: 10.1016/j.bonr.2019.100202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/06/2019] [Accepted: 03/11/2019] [Indexed: 11/27/2022] Open
Abstract
Relaxin (RLN) is an insulin-like peptide hormone that enables softening and lengthening of the pubic symphysis and uterine cervix. Here, we analyzed the effects of RLN2 on the expansion of rat midpalatal suture (MPS) using a magnetically directed liposome-based drug delivery system. Thirty-six male rats were divided into three groups: control (MPS was not expanded), lipo (expanded for 1 week with vehicle liposomes encapsulating ferric oxide and Cy5.5), and RLN-lipo (expanded for 1 week with the liposomes coated with RLN2). Rats were sacrificed after 1 week of expansion or after 2 weeks of retention. To accumulate RLN2-liposomes, a magnetic sheet was fixed to the palatal mucosa of the MPS. In vivo imaging showed magnetically controlled accumulation of liposomes in the MPS for 72 h. Immunohistochemistry revealed RLN2 expression in the MPS after expansion and relaxin receptor (RXFP) 2 expression at the osteogenic front (OF) in the RLN-lipo group; all groups expressed RXFP1 in the MPS. MPS expansion and bone formation were significantly accelerated at the OF in RLN-lipo group compared with the other groups. In the RLN-lipo group, significantly accelerated serrate bone deposition and elevated periostin (POSTN), iNOS, and MMP-1 levels were observed in the MPS. Sclerostin (SOST) expression was significantly reduced in newly formed bone in the RLN-lipo group. Our data revealed that RLN2 enhanced suture expansion via MMP-1 and iNOS secretion in the sutural fibroblasts and new bone formation via POSTN expression in osteoblasts at the OF. These properties may be useful for developing a new less-invasive orthopedic treatment aiming at sutural modification of cranio- and maxillofacial deformity patients. In vivo Magnetically localization of RLN2 carried by liposome at rat midpalatal suture (MPS) was originally performed. RLN2 promoted efficiency of the MPS expansion with secretion of Mmp1 and iNos in the mid-sutural fibroblasts. During expansion period, RLN2 increased the number and differentiation of osteoblast cells in the MPS. RLN2 enhanced newly bone formation at the MPS during expansion and retention period through Rxfp2. Sinus-like bone formation and Postn localization at the expanded MPS was observed by RLN2 administration.
Collapse
Affiliation(s)
- Hiroyuki Kamimoto
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Yukiho Kobayashi
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Keiji Moriyama
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| |
Collapse
|
5
|
Duarte C, Kobayashi Y, Morita J, Kawamoto T, Moriyama K. A preliminary investigation of the effect of relaxin on bone remodelling in suture expansion. Eur J Orthod 2018; 39:227-234. [PMID: 27141932 DOI: 10.1093/ejo/cjw037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background and objectives Relaxin (RLN) is an insulin-like hormone associated with extracellular matrix degradation, osteoclastogenesis, and osteoblast differentiation. This study aimed to assess the effect of RLN during and after lateral expansion of murine calvarial sagittal sutures. Materials and methods RLN was injected topically using a nano-sized liposome carrier into the sagittal sutures of 8- to 10-week-old wild type mice just before lateral expansion. Suture morphology, bone mineral density (BMD), and bone volume were analysed by micro-computed tomography. Collagen deposition and osteoclast differentiation were observed by Verhoeff-Van Gieson (VVG) and tartrate-resistant acid phosphatase (TRAP) staining, respectively. Results Less collagen staining and higher tissue-specific relaxin/insulin-like family peptide receptor (Rxfp)-1 and -2 expression were observed in the RLN-treated samples after 48 hours. Increased BMD and volume, and thick well-organised osteoid tissue, with multinucleated TRAP-positive cells, were observed in RLN-treated samples after 1 week. Increased Rxfp-1 expression was observed in the sagittal sutures in the mid-suture fibrous tissue following RLN treatment. Rxfp-2 was only expressed in the calvarial bone under tensile stimulation and RLN treatment further increased its expression. Limitations RLN-liposomes were not detected at any instance under the current experimental conditions. This is a preliminary study and the sample number limits the power of its results. VVG staining cannot quantify collagen contents but can provide preliminary information on the presence of collagen fibres. Conclusions RLN treatment may modify bone remodelling and collagen metabolism during and after suture expansion.
Collapse
Affiliation(s)
- Carolina Duarte
- Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Yukiho Kobayashi
- Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Jumpei Morita
- Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.,Division of Orofacial Functions and Orthodontics, Department of Health Promotion, Faculty of Dentistry, Kyushu Dental University, 2-6-1, Manazuru, Kokura-kita, Kitakyushu, Fukuoka 803-8580, Japan
| | - Tatsuo Kawamoto
- Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.,Division of Orofacial Functions and Orthodontics, Department of Health Promotion, Faculty of Dentistry, Kyushu Dental University, 2-6-1, Manazuru, Kokura-kita, Kitakyushu, Fukuoka 803-8580, Japan
| | - Keiji Moriyama
- Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| |
Collapse
|
6
|
Zeng L, Maruyama S, Nakamura K, Parker-Duffen JL, Adham IM, Zhong X, Lee HK, Querfurth H, Walsh K. The injury-induced myokine insulin-like 6 is protective in experimental autoimmune myositis. Skelet Muscle 2014; 4:16. [PMID: 25161767 PMCID: PMC4144317 DOI: 10.1186/2044-5040-4-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 06/11/2014] [Indexed: 11/13/2022] Open
Abstract
Background The idiopathic inflammatory myopathies represent a group of autoimmune diseases that are characterized by lymphocyte infiltration of muscle and muscle weakness. Insulin-like 6 (Insl6) is a poorly characterized member of the insulin-like/relaxin family of secreted proteins, whose expression is upregulated upon acute muscle injury. Methods In this study, we employed Insl6 gain or loss of function mice to investigate the role of Insl6 in a T cell-mediated model of experimental autoimmune myositis (EAM). EAM models in rodents have involved immunization with human myosin-binding protein C with complete Freund’s adjuvant (CFA) emulsions and pertussis toxin. Results Insl6-deficiency in mice led to a worsened myositis phenotype including increased infiltration of CD4 and CD8 T cells and the elevated expression of inflammatory cytokines. Insl6-deficient mice show significant motor function impairment when tested with treadmill or Rotarod devices. Conversely, muscle-specific overexpression of Insl6 protected against the development of myositis as indicated by reduced lymphocyte infiltration in muscle, diminished inflammatory cytokine expression and improved motor function. The improvement in myositis by Insl6 could also be demonstrated by acute hydrodynamic delivery of a plasmid encoding murine Insl6. In cultured cells, Insl6 inhibits Jurkat cell proliferation and activation in response to phytohemagglutinin/phorbol 12-myristate 13-acetate stimulation. Insl6 transcript expression in muscle was reduced in a cohort of dermatomyositis and polymyositis patients. Conclusions These data suggest that Insl6 may have utility for the treatment of myositis, a condition for which few treatment options exist.
Collapse
Affiliation(s)
- Ling Zeng
- Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
| | - Sonomi Maruyama
- Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
| | - Kazuto Nakamura
- Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
| | - Jennifer L Parker-Duffen
- Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
| | - Ibrahim M Adham
- Institute of Human Genetics, University of Göttingen, Göttingen, Germany
| | - Xuemei Zhong
- Hematology Oncology Section, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
| | - Han-Kyu Lee
- Department of Neurology, Rhode Island Hospital, Brown University School of Medicine, 593 Eddy St, Providence, RI 02903, USA
| | - Henry Querfurth
- Department of Neurology, Rhode Island Hospital, Brown University School of Medicine, 593 Eddy St, Providence, RI 02903, USA
| | - Kenneth Walsh
- Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
| |
Collapse
|
7
|
Duarte C, Kobayashi Y, Kawamoto T, Moriyama K. RELAXIN enhances differentiation and matrix mineralization through Relaxin/insulin-like family peptide receptor 2 (Rxfp2) in MC3T3-E1 cells in vitro. Bone 2014; 65:92-101. [PMID: 24857857 DOI: 10.1016/j.bone.2014.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 04/18/2014] [Accepted: 05/05/2014] [Indexed: 01/19/2023]
Abstract
RELAXIN (RLN) is a polypeptide hormone of the insulin-like hormone family; it facilitates birth by softening and widening the pubic symphysis and cervix in many mammals, including humans. The role of RLN in bone metabolism was recently suggested by its ability to induce osteoclastogenesis and activate osteoclast function. RLN binds to RELAXIN/INSULIN-LIKE FAMILY PEPTIDE 1 (RXFP1) and 2 (RXFP2), with varying species-specific affinities. Young men with mutated RXFP2 are at high risk for osteoporosis, as RXFP2 influences osteoblast metabolism by binding to INSULIN-LIKE PEPTIDE 3 (INSL3). However, there have been no reports on RLN function in osteoblast differentiation and mineralization or on the functionally dominant receptors for RLN in osteoblasts. We previously described Rxfp1 and 2 expression patterns in developing mouse oral components, including the maxillary and mandibular bones, Meckel's cartilage, tongue, and tooth primordia. We hypothesized that Rln/Rxfp signaling is a key mediator of skeletal development and metabolism. Here, we present the gene expression patterns of Rxfp1 and 2 in developing mouse calvarial frontal bones as determined by in situ hybridization. In addition, RLN enhanced osteoblastic differentiation and caused abnormal mineralization and extracellular matrix metabolism through Rxfp2, which was predominant over Rxfp1 in MC3T3-E1 mouse calvarial osteoblasts. Our data suggest a novel role for Rln in craniofacial skeletal development and metabolism through Rxfp2.
Collapse
Affiliation(s)
- Carolina Duarte
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
| | - Yukiho Kobayashi
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Hard Tissue Genome Research Center, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510 Japan.
| | - Tatsuo Kawamoto
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
| | - Keiji Moriyama
- Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Hard Tissue Genome Research Center, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510 Japan.
| |
Collapse
|
8
|
Asero P, Calogero AE, Condorelli RA, Mongioi' L, Vicari E, Lanzafame F, Crisci R, La Vignera S. Relevance of genetic investigation in male infertility. J Endocrinol Invest 2014; 37:415-27. [PMID: 24458834 DOI: 10.1007/s40618-014-0053-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 12/19/2013] [Indexed: 01/24/2023]
Abstract
Genetic causes can be directly responsible for various clinical conditions of male infertility and spermatogenic impairment. With the increased use of assisted reproduction technologies our understanding of genetic basis of male infertility has large implications not only for understanding the causes of infertility but also in determining the prognosis and management of such couples. For these reasons, the genetic investigations represent today an essential and useful tool in the treatment of male infertility. Several evidences are available for the clinical practice regarding the diagnosis; however, there are less information relative to the treatment of the genetic causes of male infertility. Focus of this review is to discuss the main and more common genetic causes of male infertility to better direct the genetics investigation in the treatment of spermatogenic impairment.
Collapse
Affiliation(s)
- P Asero
- Sezione di Endocrinologia, Andrologia e Medicina Interna, Dipartimento di Scienze Mediche e Pediatriche, Università di Catania, Policlinico "G. Rodolico," Bldg 4, Rm 2C18, Via S. Sofia 78, 95123, Catania, Italy
| | | | | | | | | | | | | | | |
Collapse
|
9
|
McGowan BM, Minnion JS, Murphy KG, Roy D, Stanley SA, Dhillo WS, Gardiner JV, Ghatei MA, Bloom SR. Relaxin-3 stimulates the neuro-endocrine stress axis via corticotrophin-releasing hormone. J Endocrinol 2014; 221:337-46. [PMID: 24578294 DOI: 10.1530/joe-13-0603] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Relaxin-3 is a member of the insulin superfamily. It is expressed in the nucleus incertus of the brainstem, which has projections to the hypothalamus. Relaxin-3 binds with high affinity to RXFP1 and RXFP3. RXFP3 is expressed within the hypothalamic paraventricular nucleus (PVN), an area central to the stress response. The physiological function of relaxin-3 is unknown but previous work suggests a role in appetite control, stimulation of the hypothalamic-pituitary-gonadal axis and stress. Central administration of relaxin-3 induces c-fos expression in the PVN and increases plasma ACTH levels in rats. The aim of this study was to investigate the effect of central administration of human relaxin-3 (H3) on the hypothalamic-pituitary-adrenal (HPA) axis in male rodents in vivo and in vitro. Intracerebroventricular (i.c.v) administration of H3 (5 nmol) significantly increased plasma corticosterone at 30 min following injection compared with vehicle. Intra-PVN administration of H3 (1.8-1620 pmol) significantly increased plasma ACTH at 1620 pmol H3 and corticosterone at 180-1620 pmol H3 at 30 min following injection compared with vehicle. The stress hormone prolactin was also significantly raised at 15 min post-injection compared with vehicle. Treatment of hypothalamic explants with H3 (10-1000 nM) stimulated the release of corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP), but H3 had no effect on the release of ACTH from in vitro pituitary fragments. These results suggest that relaxin-3 may regulate the HPA axis, via hypothalamic CRH and AVP neurons. Relaxin-3 may act as a central signal linking nutritional status, reproductive function and stress.
Collapse
Affiliation(s)
- B M McGowan
- Department of Diabetes and Endocrinology, Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London SE1 7EH, London Section of Investigative Medicine, Department of Medicine, Imperial College London, 6th Floor Commonwealth Building, Hammersmith Campus, Du Cane Road, London W12 ONN, UK Molecular Genetics, Rockefeller University, New York, NY 10065, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Testosterone reduces knee passive range of motion and expression of relaxin receptor isoforms via 5α-dihydrotestosterone and androgen receptor binding. Int J Mol Sci 2014; 15:4619-34. [PMID: 24642882 PMCID: PMC3975417 DOI: 10.3390/ijms15034619] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/24/2014] [Accepted: 01/27/2014] [Indexed: 12/15/2022] Open
Abstract
Ovarian steroids such as estrogen and progesterone have been reported to influence knee laxity. The effect of testosterone, however, remains unknown. This study investigated the effect of testosterone on the knee range of motion (ROM) and the molecular mechanisms that might involve changes in the expression of relaxin receptor isoforms, Rxfp1 and Rxfp2 in the patella tendon and lateral collateral ligament of the female rat knee. Ovariectomized adult female Wistar rats received three days treatment with peanut oil (control), testosterone (125 and 250 μg/kg) and testosterone (125 and 250 μg/kg) plus flutamide, an androgen receptor blocker or finasteride, a 5α-reductase inhibitor. Duplicate groups received similar treatment however in the presence of relaxin (25 ng/kg). A day after the last drug injection, knee passive ROM was measured by using a digital miniature goniometer. Both tendon and ligament were harvested and then analysed for protein and mRNA expression for Rxfp1 and Rxfp2 respectively. Knee passive ROM, Rxfp1 and Rxfp2 expression were significantly reduced following treatment with testosterone. Flutamide or finasteride administration antagonized the testosterone effect. Concomitant administration of testosterone and relaxin did not result in a significant change in knee ROM as compared to testosterone only treatment; however this was significantly increased following flutamide or finasteride addition. Testosterone effect on knee passive ROM is likely mediated via dihydro-testosterone (DHT), and involves downregulation of Rxfp1 and Rxfp2 expression, which may provide the mechanism underlying testosterone-induced decrease in female knee laxity.
Collapse
|
11
|
Relaxin receptors 1 and 2 and nuclear receptor subfamily 3, group C, member 1 (glucocorticoid receptor) mRNAs are expressed in oral components of developing mice. Arch Oral Biol 2014; 59:111-8. [DOI: 10.1016/j.archoralbio.2013.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 09/20/2013] [Accepted: 10/24/2013] [Indexed: 01/24/2023]
|
12
|
Sasser JM. The emerging role of relaxin as a novel therapeutic pathway in the treatment of chronic kidney disease. Am J Physiol Regul Integr Comp Physiol 2013; 305:R559-65. [PMID: 23883673 DOI: 10.1152/ajpregu.00528.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Emerging evidence supports a potential therapeutic role of relaxin in fibrotic diseases, including chronic kidney disease. Relaxin is a pleiotropic hormone, best characterized for its role in the reproductive system; however, recent studies have demonstrated a role of relaxin in the cardiorenal system. Both relaxin and its receptor, RXFP1, are expressed in the kidney, and relaxin has been shown to play a role in renal vasodilation, in sodium excretion, and as an antifibrotic agent. Together, these findings suggest that the kidney is a target organ of relaxin. Therefore, the purpose of this review is to describe the functional and structural impacts of relaxin treatment on the kidney and to discuss evidence that relaxin prevents disease progression in several experimental models of kidney disease. In addition, this review will present potential mechanisms that are involved in the therapeutic actions of relaxin.
Collapse
Affiliation(s)
- Jennifer M Sasser
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| |
Collapse
|
13
|
Chemical synthesis and orexigenic activity of rat/mouse relaxin-3. Amino Acids 2013; 44:1529-36. [PMID: 23456488 DOI: 10.1007/s00726-013-1478-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 02/18/2013] [Indexed: 10/27/2022]
Abstract
The insulin-like peptide, relaxin-3 was first identified just a decade ago via a genomic database search and is now recognized to be a key neuropeptide with several roles including the regulation of arousal, stress responses and neuroendocrine homeostasis. It also has significant potential as a drug to treat stress and obesity. Its actions are mediated via its cognate G protein-coupled receptor, RXFP3, which is found in abundant numbers in the brain. However, much remains to be determined with respect to the mechanism of neurological action of this peptide. Consequently, the chemical synthesis of the rat and mouse (which share identical primary structures) two-chain, three disulfide peptide was undertaken and the resulting peptide subjected to detailed in vitro and in vivo assay. Use of efficient solid-phase synthesis methods provided the two regioselectively S-protected A- and B-chains which were readily combined via sequential disulfide bond formation. The synthetic rat/mouse relaxin-3 was obtained in high purity and good overall yield. It demonstrated potent orexigenic activity in rats in that central intracerebroventricular infusion led to significantly increased food intake and water drinking.
Collapse
|
14
|
Bathgate RAD, Halls ML, van der Westhuizen ET, Callander GE, Kocan M, Summers RJ. Relaxin family peptides and their receptors. Physiol Rev 2013; 93:405-80. [PMID: 23303914 DOI: 10.1152/physrev.00001.2012] [Citation(s) in RCA: 371] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
There are seven relaxin family peptides that are all structurally related to insulin. Relaxin has many roles in female and male reproduction, as a neuropeptide in the central nervous system, as a vasodilator and cardiac stimulant in the cardiovascular system, and as an antifibrotic agent. Insulin-like peptide-3 (INSL3) has clearly defined specialist roles in male and female reproduction, relaxin-3 is primarily a neuropeptide involved in stress and metabolic control, and INSL5 is widely distributed particularly in the gastrointestinal tract. Although they are structurally related to insulin, the relaxin family peptides produce their physiological effects by activating a group of four G protein-coupled receptors (GPCRs), relaxin family peptide receptors 1-4 (RXFP1-4). Relaxin and INSL3 are the cognate ligands for RXFP1 and RXFP2, respectively, that are leucine-rich repeat containing GPCRs. RXFP1 activates a wide spectrum of signaling pathways to generate second messengers that include cAMP and nitric oxide, whereas RXFP2 activates a subset of these pathways. Relaxin-3 and INSL5 are the cognate ligands for RXFP3 and RXFP4 that are closely related to small peptide receptors that when activated inhibit cAMP production and activate MAP kinases. Although there are still many unanswered questions regarding the mode of action of relaxin family peptides, it is clear that they have important physiological roles that could be exploited for therapeutic benefit.
Collapse
Affiliation(s)
- R A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Victoria, Australia
| | | | | | | | | | | |
Collapse
|
15
|
Ahmad N, Wang W, Nair R, Kapila S. Relaxin induces matrix-metalloproteinases-9 and -13 via RXFP1: induction of MMP-9 involves the PI3K, ERK, Akt and PKC-ζ pathways. Mol Cell Endocrinol 2012; 363:46-61. [PMID: 22835547 PMCID: PMC3447121 DOI: 10.1016/j.mce.2012.07.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2012] [Accepted: 07/11/2012] [Indexed: 10/28/2022]
Abstract
We determined the precise role of relaxin family peptide (RXFP) receptors-1 and -2 in the regulation of MMP-9 and -13 by relaxin, and delineated the signaling cascade that contributes to relaxin's modulation of MMP-9 in fibrocartilaginous cells. Relaxin treatment of cells in which RXFP1 was silenced resulted in diminished induction of MMP-9 and -13 by relaxin, whereas overexpression of RXFP1 potentiated the relaxin-induced expression of these proteinases. Suppression or overexpression of RXFP2 resulted in no changes in the relaxin-induced MMP-9 and -13. Studies using chemical inhibitors and siRNAs to signaling molecules showed that PI3K, Akt, ERK and PKC-ζ and the transcription factors Elk-1, c-fos and, to a lesser extent, NF-κB are involved in relaxin's induction of MMP-9. Our findings provide the first characterization of signaling cascade involved in the regulation of any MMP by relaxin and offer mechanistic insights on how relaxin likely mediates extracellular matrix turnover.
Collapse
Affiliation(s)
- Nisar Ahmad
- The University of Michigan, Ann Arbor, MI 48109-1078, USA
| | | | | | | |
Collapse
|
16
|
Park HO, Bae J. Disturbed relaxin signaling pathway and testicular dysfunction in mouse offspring upon maternal exposure to simazine. PLoS One 2012; 7:e44856. [PMID: 22984576 PMCID: PMC3440368 DOI: 10.1371/journal.pone.0044856] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/08/2012] [Indexed: 02/01/2023] Open
Abstract
Simazine is a triazine herbicide that is being widely applied worldwide and commonly detected in surface and groundwater. Despite its popular use in controlling weeds and algae, very limited information is available regarding its toxicity. In the present study, pregnant mice were orally exposed to low doses (0, 5, 50, or 500 µg/kg body weight per day) of simazine during gestation and lactation, during which no overt maternal toxic response was detected, and their offspring was assessed. Simazine-exposed male offspring showed decreased body, testicular, and epididymis weight, increased testicular apoptosis, and decreased sperm concentrations. Differentially-expressed genes in the testes of male offspring exposed to simazine were identified by DNA microarray, revealing 775 upregulated and 791 downregulated genes; among these, the relaxin-family peptide receptor 1 (Rxfp1), which is the receptor for relaxin hormone, was significantly downregulated. In addition, the expression of target genes in the relaxin pathway, including nitric oxide synthase 2 (Nos2) and Nos3, was significantly decreased in simazine-exposed F1 testes. Moreover, simazine inhibited NO release, and knockdown of Rxfp1 blocked the inhibitory action of simazine on NO production in testicular Leydig cells. Therefore, the present study provides a better understanding of the toxicities associated with the widely used herbicide simazine at environmentally relevant doses by demonstrating that maternal exposure interferes with the pleotropic relaxin-NO signaling pathway, impairing normal development and reproductive activity of male offspring.
Collapse
Affiliation(s)
- Ho-Oak Park
- College of Pharmacy, Chung-Ang University, Seoul, Korea
| | | |
Collapse
|
17
|
Adams J, Schott S, Bern A, Renz M, Ikenberg K, Garbe C, Busch C. A novel role for relaxin-2 in the pathogenesis of primary varicosis. PLoS One 2012; 7:e39021. [PMID: 22737225 PMCID: PMC3380868 DOI: 10.1371/journal.pone.0039021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/15/2012] [Indexed: 11/26/2022] Open
Abstract
Background Varicose veins affect up to 40% of men and up to 51% of women. The pathophysiology of primary varicosis is poorly understood. Theories ranging from incompetence of the venous valves to structural changes in the vein wall have been proposed. Methodology/Principal Findings We analyzed the functional state of the intramural smooth muscle cells (n = 14 pairs matched for age and gender) and the expression of relaxin-2 and its receptors RXFP1 and RXFP2 in samples of varicose and healthy great saphenous veins (GSV) (n = 21 healthy GSV; n = 46 varicose GSV). Relaxin-2 and RXFP1 contents were determined in tissue samples (n = 9 samples per group). Pharmacological analyses were performed in a perfusion chamber. Morphometric determination of the nuclear size of the smooth muscle compartment yielded no significant difference in varicose GSV in comparison with the healthy controls. Relaxin-2 and its receptors were expressed in the muscular layer, endothelial cells and in blood vessels contained in the vein wall. Immunohistochemical expression of relaxin-2, RXFP1 and RXFP2 was significantly decreased in varicose GSV. Relaxin-2 and RXFP1 measured by ELISA and Western Blot were decreased in varicose GSV (relaxin-2 ELISA healthy vs. varicose GSV: 12.49±0.66 pg/mg versus 9.12±3.39 pg/mg of total protein; p = 0.01; Student's T-test). Contractions of vein samples induced by cholinergic or adrenergic stimulation were antagonized by relaxin-2. Conclusions/Significance We report that relaxin-2 and its receptors RXFP1 and RXFP2 are expressed in GSV and that their expression is significantly decreased in varicose GSV. Further, we were able to demonstrate a functional pharmacological relaxin-2 system in varicose GSV. Our results suggest a novel role for relaxin-2 in the pathogenesis of primary varicosis, rendering relaxin-2 a novel possible pharmacological agent for the treatment of this widely prevailing venous disease.
Collapse
Affiliation(s)
- Julia Adams
- Department of Dermatology, University of Tuebingen, Tuebingen, Germany
| | - Sarah Schott
- Department of Gynecology, University of Heidelberg, Heidelberg, Germany
| | - Arno Bern
- Practice Clinic of Phlebology, Tuebingen, Germany
| | - Matthias Renz
- Department of Dermatology, University of Tuebingen, Tuebingen, Germany
| | | | - Claus Garbe
- Department of Dermatology, University of Tuebingen, Tuebingen, Germany
| | - Christian Busch
- Department of Dermatology, University of Tuebingen, Tuebingen, Germany
- * E-mail:
| |
Collapse
|
18
|
Royce SG, Cheng V, Samuel CS, Tang MLK. The regulation of fibrosis in airway remodeling in asthma. Mol Cell Endocrinol 2012; 351:167-75. [PMID: 22266540 DOI: 10.1016/j.mce.2012.01.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 01/04/2012] [Indexed: 01/12/2023]
Abstract
Fibrosis is one of the key pathological features of airway remodeling in asthma. In the normal airway the amount of collagen and other extracellular matrix components is kept in equilibrium by regulation of synthesis and degradation. In asthma this homeostasis is disrupted due to genetic and environmental factors. In the airways of patients with the disease there is increased extracellular matrix deposition, particularly in the reticular basement membrane region, lamina propria and submucosa. Fibrosis is important as it can occur early in the pathogenesis of asthma, be associated with severity and resistant to therapy. In this review we will discuss current knowledge of relaxin and other key regulators of fibrosis in the airway including TGFβ, Smad2/3 and matrix metalloproteinases. As fibrosis is not directly targeted or effectively treated by current asthma drugs including corticosteroids, characterization of airway fibrosis and how it is regulated will be essential for the development of novel therapies for asthma.
Collapse
Affiliation(s)
- Simon G Royce
- Department of Allergy and Immunology, Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne 3052, Australia
| | | | | | | |
Collapse
|
19
|
Vandevoort CA, Mtango NR, Latham KE, Stewart DR. Primate preimplantation embryo is a target for relaxin during early pregnancy. Fertil Steril 2011; 96:203-7. [PMID: 21645893 DOI: 10.1016/j.fertnstert.2011.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To determine whether preimplantation embryos are targets for relaxin secreted from the corpus luteum of the menstrual cycle. DESIGN Rhesus monkey oocytes obtained from females undergoing controlled ovarian hyperstimulation were inseminated, and the resulting embryos were cultured in medium with or without recombinant human relaxin (20 ng/mL) for 8 days. SETTING Research laboratory. ANIMAL(S) Rhesus monkey. INTERVENTION(S) Controlled ovarian stimulation to obtain oocytes for in vitro-produced embryos that were cultured with or without human recombinant relaxin. MAIN OUTCOME MEASURE(S) Rate of blastocyst development, percentage of blastocysts, and inner cell mass/trophectoderm cell ratio were measured on day 8 of culture. The presence of relaxin receptor (RXFP1) messenger RNA in eight-cell embryos was observed by array hybridization. RESULT(S) RXFP1 receptor expression was localized to the inner cell mass of blastocysts, as shown by immunohistochemistry. The percentage of embryos that developed to blastocyst and the inner cell mass/trophectoderm cell ratio was unchanged with relaxin supplementation; however, the relaxin-treated embryos developed into blastocysts significantly sooner than untreated embryos. CONCLUSION(S) These results are the first evidence that the preimplantation primate embryo is a target for relaxin and that the addition of relaxin to in vitro culture medium enhances rhesus monkey embryo development.
Collapse
Affiliation(s)
- Catherine A Vandevoort
- California National Primate Research Center, University of California, Davis, CA 95616, USA.
| | | | | | | |
Collapse
|
20
|
Feugang JM, Rodriguez-Munoz JC, Willard ST, Bathgate RA, Ryan PL. Examination of relaxin and its receptors expression in pig gametes and embryos. Reprod Biol Endocrinol 2011; 9:10. [PMID: 21251292 PMCID: PMC3032664 DOI: 10.1186/1477-7827-9-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 01/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Relaxin is a small peptide also known as pregnancy hormone in many mammals. It is synthesized by both male and female tissues, and its secretions are found in various body fluids such as plasma serum, ovarian follicular fluid, utero-oviduct secretions, and seminal plasma of many mammals, including pigs. However, the presence and effects of relaxin in porcine gametes and embryos are still not well-known. The purpose of this study was to assess the presence of relaxin and its receptors RXFP1 and RXFP2 in pig gametes and embryos. METHODS Immature cumulus-oocyte complexes (COCs) were aspirated from sows' ovaries collected at the abattoir. After in vitro-maturation, COCs were in vitro-fertilized and cultured. For studies, immature and mature COCs were separately collected, and oocytes were freed from their surrounding cumulus cells. Denuded oocytes, cumulus cells, mature boar spermatozoa, zygotes, and embryos (cleaved and blastocysts) were harvested for temporal and spatial gene expression studies. Sections of ovary, granulosa and neonatal porcine uterine cells were also collected to use as controls. RESULTS Using both semi-quantitative and quantitative PCRs, relaxin transcripts were not detected in all tested samples, while RXFP1 and RXFP2 mRNA were present. Both receptor gene products were found at higher levels in oocytes compared to cumulus cells, irrespective of the maturation time. Cleaved-embryos contained higher levels of RXFP2 mRNA, whereas, blastocysts were characterized by a higher RXFP1 mRNA content. Using western-immunoblotting or in situ immunofluorescence, relaxin and its receptor proteins were detected in all samples. Their fluorescence intensities were consistently more important in mature oocytes than immature ones. The RXFP1 and RXFP2 signal intensities were mostly located in the plasma membrane region, while the relaxin ones appeared homogeneously distributed within the oocytes and embryonic cells. Furthermore, spermatozoa displayed stronger RXFP2 signal than RXFP1 after western-immunoblotting. CONCLUSION All together, our findings suggest potential roles of relaxin and its receptors during oocyte maturation, early embryo development, and beyond.
Collapse
Affiliation(s)
- Jean M Feugang
- Department of Animal & Dairy Sciences, Mississippi State University, 4025 Wise Center, Mississippi State, MS 38762, USA
| | - Juan C Rodriguez-Munoz
- Department of Animal & Dairy Sciences, Mississippi State University, 4025 Wise Center, Mississippi State, MS 38762, USA
| | - Scott T Willard
- Department of Biochemistry & Molecular Biology, Mississippi State University, 402 Dorman Hall, Mississippi, MS 38762, USA
| | - Ross A Bathgate
- Florey Neuroscience Institutes, University of Melbourne, Gate 11, Royal Parade, Victoria, 3010, Australia
| | - Peter L Ryan
- Department of Animal & Dairy Sciences, Mississippi State University, 4025 Wise Center, Mississippi State, MS 38762, USA
- Department of Pathobiology & Population Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 38762, USA
| |
Collapse
|
21
|
Relaxin-3/INSL7 Regulates the Stress-response System in the Rat Hypothalamus. J Mol Neurosci 2010; 43:169-74. [DOI: 10.1007/s12031-010-9468-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Accepted: 10/27/2010] [Indexed: 11/25/2022]
|
22
|
Zeng L, Akasaki Y, Sato K, Ouchi N, Izumiya Y, Walsh K. Insulin-like 6 is induced by muscle injury and functions as a regenerative factor. J Biol Chem 2010; 285:36060-9. [PMID: 20807758 DOI: 10.1074/jbc.m110.160879] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The insulin-like family of factors are involved in the regulation of a variety of physiological processes, but the function of the family member termed insulin-like 6 (Insl6) in skeletal muscle has not been reported. We show that Insl6 is a myokine that is up-regulated in skeletal muscle downstream of Akt signaling and in regenerating muscle in response to cardiotoxin (CTX)-induced injury. In the CTX injury model, myofiber regeneration was improved by the intramuscular or systemic delivery of an adenovirus expressing Insl6. Skeletal muscle-specific Insl6 transgenic mice exhibited normal muscle mass under basal conditions but elevated satellite cell activation and enhanced muscle regeneration in response to CTX injury. The Insl6-mediated regenerative response was associated with reductions in muscle cell apoptosis and reduced serum levels of creatine kinase M. Overexpression of Insl6 stimulated proliferation and reduced apoptosis in cultured myogenic cells. Conversely, knockdown of Insl6 reduced proliferation and increased apoptosis. These data indicate that Insl6 is an injury-regulated myokine that functions as a myogenic regenerative factor.
Collapse
Affiliation(s)
- Ling Zeng
- Molecular Cardiology/Whitaker Cardiovascular Institute, Boston University Medical Campus, Boston, Massachusetts 02118, USA
| | | | | | | | | | | |
Collapse
|
23
|
Michaelson D, Korta DZ, Capua Y, Hubbard EJA. Insulin signaling promotes germline proliferation in C. elegans. Development 2010; 137:671-80. [PMID: 20110332 DOI: 10.1242/dev.042523] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cell proliferation must be coordinated with cell fate specification during development, yet interactions among pathways that control these two critical aspects of development are not well understood. The coordination of cell fate specification and proliferation is particularly crucial during early germline development, when it impacts the establishment of stem/progenitor cell populations and ultimately the production of gametes. In C. elegans, insulin/IGF-like receptor (IIR) signaling has been implicated in fertility, but the basis for the fertility defect had not been previously characterized. We found that IIR signaling is required for robust larval germline proliferation, separate from its well-characterized role in preventing dauer entry. IIR signaling stimulates the larval germline cell cycle. This activity is distinct from Notch signaling, occurs in a predominantly germline-autonomous manner, and responds to somatic activity of ins-3 and ins-33, genes that encode putative insulin-like ligands. IIR signaling in this role acts through the canonical PI3K pathway, inhibiting DAF-16/FOXO. However, signaling from these ligands does not inhibit daf-16 in neurons nor in the intestine, two tissues previously implicated in other IIR roles. Our data are consistent with a model in which: (1) under replete reproductive conditions, the larval germline responds to insulin signaling to ensure robust germline proliferation that builds up the germline stem cell population; and (2) distinct insulin-like ligands contribute to different phenotypes by acting on IIR signaling in different tissues.
Collapse
Affiliation(s)
- David Michaelson
- Developmental Genetics Program, Helen and Martin Kimmel Center for Stem Cell Biology, Skirball Institute of Biomolecular Medicine, Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | | | | | | |
Collapse
|
24
|
Sajid W, Holst PA, Kiselyov VV, Andersen AS, Conlon JM, Kristensen C, Kjeldsen T, Whittaker J, Chan SJ, De Meyts P. Structural basis of the aberrant receptor binding properties of hagfish and lamprey insulins. Biochemistry 2009; 48:11283-95. [PMID: 19863112 PMCID: PMC2781304 DOI: 10.1021/bi901269j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
The insulin from the Atlantic hagfish (Myxine glutinosa) has been one of the most studied insulins from both a structural and a biological viewpoint; however, some aspects of its biology remain controversial, and there has been no satisfying structural explanation for its low biological potency. We have re-examined the receptor binding kinetics, as well as the metabolic and mitogenic properties, of this phylogenetically ancient insulin, as well as that from another extant representative of the ancient chordates, the river lamprey (Lampetra fluviatilis). Both insulins share unusual binding kinetics and biological properties with insulin analogues that have single mutations at residues that contribute to the hexamerization surface. We propose and demonstrate by reciprocal amino acid substitutions between hagfish and human insulins that the reduced biological activity of hagfish insulin results from unfavorable substitutions, namely, A10 (Ile to Arg), B4 (Glu to Gly), B13 (Glu to Asn), and B21 (Glu to Val). We likewise suggest that the altered biological activity of lamprey insulin may reflect substitutions at A10 (Ile to Lys), B4 (Glu to Thr), and B17 (Leu to Val). The substitution of Asp at residue B10 in hagfish insulin and of His at residue A8 in both hagfish and lamprey insulins may help compensate for unfavorable changes in other regions of the molecules. The data support the concept that the set of unusual properties of insulins bearing certain mutations in the hexamerization surface may reflect those of the insulins evolutionarily closer to the ancestral insulin gene product.
Collapse
Affiliation(s)
- Waseem Sajid
- Receptor Systems Biology Laboratory, Hagedorn Research Institute, Gentofte, Denmark.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
De Meyts P, Gauguin L, Svendsen AM, Sarhan M, Knudsen L, Nøhr J, Kiselyov VV. Structural basis of allosteric ligand-receptor interactions in the insulin/relaxin peptide family: implications for other receptor tyrosine kinases and G-protein-coupled receptors. Ann N Y Acad Sci 2009; 1160:45-53. [PMID: 19416158 DOI: 10.1111/j.1749-6632.2009.03837.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The insulin/relaxin superfamily of peptide hormones comprises 10 members in humans. The three members of the insulin-related subgroup bind to receptor tyrosine kinases (RTKs), while four of the seven members of the relaxin-like subgroup are now known to bind to G-protein-coupled receptors (GPCRs), the so-called relaxin family peptide receptors (RXFPs). Both systems have a long evolutionary history and play a critical role in fundamental biological processes, such as metabolism, growth, survival and longevity, and reproduction. The structural biology and ligand-binding kinetics of the insulin and insulin-like growth factor I receptors have been studied in great detail, culminating in the recent crystal structure of the insulin receptor extracellular domain. Some of the fundamental properties of these receptors, including constitutive dimerization and negative cooperativity, have recently been shown to extend to other RTKs and GPCRs, including RXFPs, confirming kinetic observations made over 30 years ago.
Collapse
Affiliation(s)
- Pierre De Meyts
- Receptor Systems Biology Laboratory, Hagedorn Research Institute, Gentofte, Denmark
| | | | | | | | | | | | | |
Collapse
|
26
|
Svendsen AM, Vrecl M, Knudsen L, Heding A, Wade JD, Bathgate RAD, De Meyts P, Nøhr J. Dimerization and Negative Cooperativity in the Relaxin Family Peptide Receptors. Ann N Y Acad Sci 2009; 1160:54-9. [DOI: 10.1111/j.1749-6632.2009.03835.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
27
|
Svendsen AM, Zalesko A, Kønig J, Vrecl M, Heding A, Kristensen JB, Wade JD, Bathgate RAD, De Meyts P, Nøhr J. Negative cooperativity in H2 relaxin binding to a dimeric relaxin family peptide receptor 1. Mol Cell Endocrinol 2008; 296:10-7. [PMID: 18723073 DOI: 10.1016/j.mce.2008.07.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 07/16/2008] [Accepted: 07/22/2008] [Indexed: 11/26/2022]
Abstract
H2 relaxin, a member of the insulin superfamily, binds to the G-protein-coupled receptor RXFP1 (relaxin family peptide 1), a receptor that belongs to the leucine-rich repeat (LRR)-containing subgroup (LGRs) of class A GPCRs. We recently demonstrated negative cooperativity in INSL3 binding to RXFP2 and showed that this subgroup of GPCRs functions as constitutive dimers. In this work, we investigated whether the binding of H2 relaxin to RXFP1 also shows negative cooperativity, and whether this receptor functions as a dimer using BRET(2). Both binding and dissociation were temperature dependent, and the pH optimum for binding was pH 7.0. Our results showed that RXFP1 is a constitutive dimer with negative cooperativity in ligand binding, that dimerization occurs through the 7TM domain, and that the ectodomain has a stabilizing effect on this interaction. Dimerization and negative cooperativity appear to be general properties of LGRs involved in reproduction as well as other GPCRs.
Collapse
|
28
|
Filonzi M, Cardoso LC, Pimenta MT, Queiróz DBC, Avellar MCW, Porto CS, Lazari MFM. Relaxin family peptide receptors Rxfp1 and Rxfp2: mapping of the mRNA and protein distribution in the reproductive tract of the male rat. Reprod Biol Endocrinol 2007; 5:29. [PMID: 17623071 PMCID: PMC1947996 DOI: 10.1186/1477-7827-5-29] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 07/10/2007] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Relaxin is the endogenous ligand of the G-protein coupled receptor RXFP1, previously known as LGR7. In humans relaxin can also activate, but with lower affinity, the closely related receptor for the insulin-like peptide from Leydig cells, RXFP2, previously known as LGR8. The lack of relaxin impairs male fertility but the precise distribution and the function of relaxin receptors in the male reproductive tract is not known. We investigated the distribution of Rxfp1 and Rxfp2 in the reproductive tract of the male rat and the function of relaxin in the vas deferens, a tissue with high expression of both receptors. METHODS The presence of mRNA for Rxfp1 and Rxfp2 was investigated in testes, cultured Sertoli cells, epididymis, vas deferens, seminal vesicle, prostate, and spermatozoa by RT-PCR and Southern blot. Protein expression in the testis, vas deferens, primary culture of Sertoli cells, and spermatozoa was assessed by immunohistochemistry and immunofluorescence. The role of relaxin in the vas deferens was evaluated by contractility studies and radioimmunoassay of cAMP production. The effect of relaxin on mRNA levels for metalloproteinase-7 was measured by Northern blot. RESULTS Transcripts for Rxfp1 and Rxfp2 were present in almost all parts of the male reproductive tract, with high levels in testis and vas deferens. Both receptors were immunolocalized in late stage germ cells but not in mature spermatozoa, although mRNAs for both receptors were also present in mature spermatozoa. Rxfp1 but not Rxfp2 was detected in cultured Sertoli cells. Strong immunostaining for Rxfp1 and Rxfp2 was seen in muscular and epithelial layers of the vas deferens and in arteriolar walls. Relaxin did not affect contractility and cyclic AMP production of the vas deferens, but increased the levels of mRNA for metalloproteinase-7. CONCLUSION Rxfp1 and Rxfp2 are widely and similarly distributed throughout the male reproductive tract. Our results suggest that Rxfp1 on spermatids and Sertoli cells may be important in spermatogenesis. Relaxin in the vas deferens does not affect contractility, but may affect vascular compliance and collagen and matrix remodeling.
Collapse
Affiliation(s)
- Marcelo Filonzi
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| | - Laís C Cardoso
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| | - Maristela T Pimenta
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| | - Daniel BC Queiróz
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| | - Maria CW Avellar
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| | - Catarina S Porto
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| | - Maria FM Lazari
- Department of Pharmacology, Section of Experimental Endocrinology, Federal University of São Paulo, Rua Três de Maio, 100, CEP 04044-020, São Paulo, SP, Brazil
| |
Collapse
|
29
|
Insel PA, Tang CM, Hahntow I, Michel MC. Impact of GPCRs in clinical medicine: monogenic diseases, genetic variants and drug targets. BIOCHIMICA ET BIOPHYSICA ACTA 2007; 1768:994-1005. [PMID: 17081496 PMCID: PMC2169201 DOI: 10.1016/j.bbamem.2006.09.029] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/28/2006] [Accepted: 09/29/2006] [Indexed: 12/15/2022]
Abstract
By virtue of their large number, widespread distribution and important roles in cell physiology and biochemistry, G-protein-coupled receptors (GPCR) play multiple important roles in clinical medicine. Here, we focus on 3 areas that subsume much of the recent work in this aspect of GPCR biology: (1) monogenic diseases of GPCR; (2) genetic variants of GPCR; and (3) clinically useful pharmacological agonists and antagonists of GPCR. Diseases involving mutations of GPCR are rare, occurring in <1/1000 people, but disorders in which antibodies are directed against GPCR are more common. Genetic variants, especially single nucleotide polymorphisms (SNPs), show substantial heterogeneity in frequency among different GPCRs but have not been evaluated for some GPCR. Many therapeutic agonists and antagonists target GPCR and show inter-subject variability in terms of efficacy and toxicity. For most of those agents, it remains an open question whether genetic variation in primary sequence of the GPCR is an important contributor to such inter-subject variability, although this is an active area of investigation.
Collapse
Affiliation(s)
- Paul A Insel
- University of California San diego, Department of Pharmacology, La Jolla, CA 92093-0636, USA.
| | | | | | | |
Collapse
|
30
|
Silvertown JD, Symes JC, Neschadim A, Nonaka T, Kao JCH, Summerlee AJS, Medin JA. Analog of H2 relaxin exhibits antagonistic properties and impairs prostate tumor growth. FASEB J 2006; 21:754-65. [PMID: 17197386 DOI: 10.1096/fj.06-6847com] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hormone antagonists can be effective tools to delineate receptor signaling pathways and their resulting downstream physiological actions. Mutation of the receptor binding domain (RBD) of human H2 relaxin (deltaH2) impaired its biological function as measured by cAMP signaling. In a competition assay, deltaH2 exhibited antagonistic activity by blocking recombinant H2 relaxin from binding to receptors on THP-1 cells. In a flow cytometry-based binding assay, deltaH2 demonstrated weak binding to 293T cells expressing the LGR7 receptor in the presence of biotinylated H2 relaxin. When human prostate cancer cell lines (PC-3 and LNCaP) were engineered to overexpress eGFP, wild-type (WT) H2, or deltaH2, and subsequently implanted into NOD/SCID mice, tumor xenografts overexpressing deltaH2 displayed smaller volumes compared to H2 and eGFP controls. Plasma osmolality readings and microvessel density and area assessment suggest that deltaH2 modulates physiological parameters in vivo. In a second murine model, intratumoral injections of lentivectors engineered to express deltaH2/eGFP led to suppressed tumor growth compared to controls. This study provides further evidence supporting a role for H2 relaxin in prostate tumor growth. More importantly, we report how mutation of the H2 relaxin RBD confers the hormone derivative with antagonistic properties, offering a novel reagent for relaxin research.
Collapse
Affiliation(s)
- Josh D Silvertown
- Division of Stem Cell and Developmental Biology, Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
31
|
Olinski RP, Dahlberg C, Thorndyke M, Hallböök F. Three insulin-relaxin-like genes in Ciona intestinalis. Peptides 2006; 27:2535-46. [PMID: 16920224 DOI: 10.1016/j.peptides.2006.06.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 06/21/2006] [Accepted: 06/21/2006] [Indexed: 02/02/2023]
Abstract
The Ciona intestinalis genome harbors three insulin-like genes: INS-L1, -L2 and -L3. Conserved synteny between the Ciona-human genomes predicts that Ciona INS-Ls are orthologous to the vertebrate insulin-relaxin family, but this relation cannot be inferred from molecular phylogeny. A conserved protein core with six cysteines; typical arrangement of B-, C- and A-protein domains; pro-protein maturation mode; and putative insulin receptor-binding sites were identified in Ciona INS-L proteins. ESTs used to assemble exonic sequences of INS-Ls combined with qRT-PCR analysis provided evidence that the predicted genes are expressed in the developing and adult Ciona. Our results support that Ciona INS-L1 is orthologous to the vertebrate insulin-like/relaxin genes, INS-L2 to insulin genes and INS-L3 to IGF genes. Our analysis also implies that the insulin-like/relaxin ancestor switched receptor type from tyrosine kinase- to GPCR-type, whereas insulin-IGF subfamily retained the tyrosine kinase-type of receptor. We propose that this receptor-switch occurred after the time when urochordates branched from the common chordate lineage, but before the two genome-duplications at the root of the vertebrates.
Collapse
Affiliation(s)
- Robert Piotr Olinski
- Department of Neuroscience, Unit for Developmental Neuroscience, Uppsala University, BMC, Box 587, S-751 23 Uppsala, Sweden
| | | | | | | |
Collapse
|
32
|
Del Borgo MP, Hughes RA, Bathgate RAD, Lin F, Kawamura K, Wade JD. Analogs of Insulin-like Peptide 3 (INSL3) B-chain Are LGR8 Antagonists in Vitro and in Vivo. J Biol Chem 2006; 281:13068-13074. [PMID: 16547350 DOI: 10.1074/jbc.m600472200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin-like peptide 3 (INSL3) is a member of the insulin superfamily that plays an important role in mediating testes descent during fetal development. More recently, it has also been demonstrated to initiate oocyte maturation and suppress male germ cell apoptosis. These actions are mediated via a specific G-protein-coupled receptor, LGR8. Little is known regarding the structure and function relationship of INSL3, although it is believed that the principal receptor binding site resides within its B-chain. We subsequently observed that the linear B-chain alone (INSL3B-(1-31)) bound to LGR8 and was able to antagonise INSL3 stimulated cAMP accumulation in HEK-293T cells expressing LGR8. Sequentially N- and C-terminally shortened linear analogs were prepared by solid phase synthesis and subsequent assay showed that the minimum length required for binding was residues 11-27. It was also observed that increased binding affinity correlated with a corresponding increase in alpha-helical content as measured by circular dichroism spectroscopy. Molecular modeling studies suggested that judicious placement of a conformational constraint within this peptide would increase its alpha-helix content and result in increased structural similarity to the B-chain within native INSL3. Consequently, intramolecularly disulfide-linked analogs of the B-chain showed a potentiation of INSL3 antagonistic activity, as well as exhibiting increased proteolytic stability, as assessed in rat serum in vitro. Administration of one of these peptides into the testes of rats resulted in a substantial decrease in testis weight probably due to the inhibition of germ cell survival, suggesting that INSL3 antagonists may have potential as novel contraceptive agents.
Collapse
Affiliation(s)
- Mark P Del Borgo
- Howard Florey Institute, Victoria 3010, Australia; Department of Pharmacology, University of Melbourne, Victoria 3010, Australia
| | - Richard A Hughes
- Department of Pharmacology, University of Melbourne, Victoria 3010, Australia
| | | | - Feng Lin
- Howard Florey Institute, Victoria 3010, Australia
| | - Kazu Kawamura
- Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, California 94305-5317
| | - John D Wade
- Howard Florey Institute, Victoria 3010, Australia.
| |
Collapse
|
33
|
Bathgate RAD, Lin F, Hanson NF, Otvos L, Guidolin A, Giannakis C, Bastiras S, Layfield SL, Ferraro T, Ma S, Zhao C, Gundlach AL, Samuel CS, Tregear GW, Wade JD. Relaxin-3: Improved Synthesis Strategy and Demonstration of Its High-Affinity Interaction with the Relaxin Receptor LGR7 BothIn VitroandIn Vivo†. Biochemistry 2006; 45:1043-53. [PMID: 16411781 DOI: 10.1021/bi052233e] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Relaxin-3 is a member of the human relaxin peptide family, the gene for which, RLN3, is predominantly expressed in the brain. Mapping studies in the rodent indicate a highly developed network of RLN3, RLN1, and relaxin receptor-expressing cells in the brain, suggesting that relaxin peptides have important functional roles in the central nervous system. A regioselective disulfide-bond synthesis protocol was developed and used for the chemical synthesis of human (H3) relaxin-3. The selectively S-protected A and B chains were combined by stepwise formation of each of the three insulin-like disulfides via aeration, thioloysis, and iodolysis. Judicious positioning of the three sets of S-protecting groups was crucial for acquisition of synthetic H3 relaxin in a good overall yield. The activity of the peptide was tested against relaxin family peptide receptors. Although the highest activity was demonstrated on the human relaxin-3 receptor (GPCR135), the peptide also showed high activity on relaxin receptors (LGR7) from various species and variable activity on the INSL3 receptor (LGR8). Recombinant mouse prorelaxin-3 demonstrated similar activity to H3 relaxin, suggesting that the presence of the C peptide did not influence the conformation of the active site. H3 relaxin was also able to activate native LGR7 receptors. It stimulated increased MMP-2 expression in LGR7-expressing rat ventricular fibroblasts in a dose-dependent manner and, following infusion into the lateral ventricle of the brain, stimulated water drinking in rats, activating LGR7 receptors located in the subfornical organ. Thus, H3 relaxin is able to interact with the relaxin receptor LGR7 both in vitro and in vivo.
Collapse
Affiliation(s)
- Ross A D Bathgate
- Howard Florey Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Ma S, Shen PJ, Burazin TCD, Tregear GW, Gundlach AL. Comparative localization of leucine-rich repeat-containing G-protein-coupled receptor-7 (RXFP1) mRNA and [33P]-relaxin binding sites in rat brain: Restricted somatic co-expression a clue to relaxin action? Neuroscience 2006; 141:329-44. [PMID: 16725278 DOI: 10.1016/j.neuroscience.2006.03.076] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 03/09/2006] [Accepted: 03/23/2006] [Indexed: 11/16/2022]
Abstract
Relaxin is a polypeptide hormone with established actions associated with reproductive physiology, but until recently the precise nature of the relaxin receptor and its transmembrane signaling mechanisms had remained elusive. In 2002 however, the leucine-rich-repeat-containing G-protein-coupled receptor-7 (now classified as RXFP1) was identified as a cognate receptor for relaxin, with activation resulting in stimulation of intracellular cAMP production. These findings, along with the presence and putative actions of relaxin within the CNS and earlier descriptions of relaxin binding sites in brain, suggest the importance and feasibility of determining if these relaxin binding sites represent leucine-rich-repeat-containing G-protein-coupled receptor-7 and their precise comparative distribution. Thus, the current study reports the distribution of leucine-rich-repeat-containing G-protein-coupled receptor-7 mRNA throughout the rat brain using in situ hybridization histochemistry of [(35)S]-labeled oligonucleotides and the comparative distribution of [(33)P]-human relaxin binding sites. The extensive, topographical distribution of leucine-rich-repeat-containing G-protein-coupled receptor-7 mRNA throughout the adult rat brain correlated very closely to that of [(33)P]-relaxin binding sites. Leucine-rich-repeat-containing G-protein-coupled receptor-7 mRNA was expressed by neurons in several brain regions, including the olfactory bulb, cerebral cortex, thalamus, hippocampus, hypothalamus, midbrain, pons and medulla. Receptor transcripts were most abundant in areas such as the basolateral amygdala, subiculum, deep layers of the cingulate, somatosensory and motor cortices and intralaminar/midline thalamic nuclei. These areas also contained very high densities of [(33)P]-relaxin binding sites, suggesting a largely somatic localization of leucine-rich-repeat-containing G-protein-coupled receptor-7 protein and site of action for relaxin peptide. The central distribution of relaxin-producing neurons has been described, while data on the topography of nerve terminals that contain and secrete the peptide are currently lacking; but overall these findings strongly suggest that leucine-rich-repeat-containing G-protein-coupled receptor-7 is the cognate receptor for relaxin in the rat brain, and support a role for relaxin-leucine-rich-repeat-containing G-protein-coupled receptor-7 signaling in various somatosensory, autonomic and neurohumoral pathways, which warrants further investigation.
Collapse
Affiliation(s)
- S Ma
- Howard Florey Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia.
| | | | | | | | | |
Collapse
|