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Gupta D, Burstein AW, Schwalbe DC, Shankar K, Varshney S, Singh O, Paul S, Ogden SB, Osborne-Lawrence S, Metzger NP, Richard CP, Campbell JN, Zigman JM. Ghrelin deletion and conditional ghrelin cell ablation increase pancreatic islet size in mice. J Clin Invest 2023; 133:e169349. [PMID: 38099492 PMCID: PMC10721155 DOI: 10.1172/jci169349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 10/05/2023] [Indexed: 12/18/2023] Open
Abstract
Ghrelin exerts key effects on islet hormone secretion to regulate blood glucose levels. Here, we sought to determine whether ghrelin's effects on islets extend to the alteration of islet size and β cell mass. We demonstrate that reducing ghrelin - by ghrelin gene knockout (GKO), conditional ghrelin cell ablation, or high-fat diet (HFD) feeding - was associated with increased mean islet size (up to 62%), percentage of large islets (up to 854%), and β cell cross-sectional area (up to 51%). In GKO mice, these effects were more apparent in 10- to 12-week-old mice than in 4-week-old mice. Higher β cell numbers from decreased β cell apoptosis drove the increase in β cell cross-sectional area. Conditional ghrelin cell ablation in adult mice increased the β cell number per islet by 40% within 4 weeks. A negative correlation between islet size and plasma ghrelin in HFD-fed plus chow-fed WT mice, together with even larger islet sizes in HFD-fed GKO mice than in HFD-fed WT mice, suggests that reduced ghrelin was not solely responsible for diet-induced obesity-associated islet enlargement. Single-cell transcriptomics revealed changes in gene expression in several GKO islet cell types, including upregulation of Manf, Dnajc3, and Gnas expression in β cells, which supports decreased β cell apoptosis and/or increased β cell proliferation. These effects of ghrelin reduction on islet morphology might prove useful when designing new therapies for diabetes.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Avi W. Burstein
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Dana C. Schwalbe
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Subhojit Paul
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sean B. Ogden
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Nathan P. Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Corine P. Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine and
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
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Common and female-specific roles of protein tyrosine phosphatase receptors N and N2 in mice reproduction. Sci Rep 2023; 13:355. [PMID: 36611058 PMCID: PMC9825377 DOI: 10.1038/s41598-023-27497-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
Simultaneous knockout of the neuroendocrine marker genes Ptprn and Ptprn2, which encode the protein tyrosine phosphatase receptors N and N2, causes infertility in female mice while males are fertile. To elucidate the mechanism of the sex-specific roles of Ptprn and Ptprn2 in mouse reproduction, we analyzed the effects of their double knockout (DKO) on the hypothalamic-pituitary-gonadal axis. In DKO females, delayed puberty and lack of ovulation were observed, complemented by changes in ovarian gene expression and steroidogenesis. In contrast, testicular gene expression, steroidogenesis, and reproductive organs development were not significantly affected in DKO males. However, in both sexes, pituitary luteinizing hormone (LH) beta gene expression and LH levels were reduced, as well as follicle-stimulating hormone beta gene and gonadotropin-releasing hormone (GnRH) gene, while the calcium-mobilizing and LH secretory actions of GnRH were preserved. Hypothalamic Gnrh1 and Kiss1 gene expression was also reduced in DKO females and males. In parallel, a significant decrease in the density of immunoreactive GnRH and kisspeptin fibers was detected in the hypothalamic arcuate nucleus of DKO females and males. The female-specific kisspeptin immunoreactivity in the rostral periventricular region of the third ventricle was also reduced in DKO females, but not in DKO males. These data indicate a critical role of Ptprn and Ptprn2 in kisspeptin-GnRH neuronal function and sexual dimorphism in the threshold levels of GnRH required to preserve reproductive functions.
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Powell DR, Revelli JP, Doree DD, DaCosta CM, Desai U, Shadoan MK, Rodriguez L, Mullens M, Yang QM, Ding ZM, Kirkpatrick LL, Vogel P, Zambrowicz B, Sands AT, Platt KA, Hansen GM, Brommage R. High-Throughput Screening of Mouse Gene Knockouts Identifies Established and Novel High Body Fat Phenotypes. Diabetes Metab Syndr Obes 2021; 14:3753-3785. [PMID: 34483672 PMCID: PMC8409770 DOI: 10.2147/dmso.s322083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/04/2021] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Obesity is a major public health problem. Understanding which genes contribute to obesity may better predict individual risk and allow development of new therapies. Because obesity of a mouse gene knockout (KO) line predicts an association of the orthologous human gene with obesity, we reviewed data from the Lexicon Genome5000TM high throughput phenotypic screen (HTS) of mouse gene KOs to identify KO lines with high body fat. MATERIALS AND METHODS KO lines were generated using homologous recombination or gene trapping technologies. HTS body composition analyses were performed on adult wild-type and homozygous KO littermate mice from 3758 druggable mouse genes having a human ortholog. Body composition was measured by either DXA or QMR on chow-fed cohorts from all 3758 KO lines and was measured by QMR on independent high fat diet-fed cohorts from 2488 of these KO lines. Where possible, comparisons were made to HTS data from the International Mouse Phenotyping Consortium (IMPC). RESULTS Body fat data are presented for 75 KO lines. Of 46 KO lines where independent external published and/or IMPC KO lines are reported as obese, 43 had increased body fat. For the remaining 29 novel high body fat KO lines, Ksr2 and G2e3 are supported by data from additional independent KO cohorts, 6 (Asnsd1, Srpk2, Dpp8, Cxxc4, Tenm3 and Kiss1) are supported by data from additional internal cohorts, and the remaining 21 including Tle4, Ak5, Ntm, Tusc3, Ankk1, Mfap3l, Prok2 and Prokr2 were studied with HTS cohorts only. CONCLUSION These data support the finding of high body fat in 43 independent external published and/or IMPC KO lines. A novel obese phenotype was identified in 29 additional KO lines, with 27 still lacking the external confirmation now provided for Ksr2 and G2e3 KO mice. Undoubtedly, many mammalian obesity genes remain to be identified and characterized.
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Affiliation(s)
- David R Powell
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Jean-Pierre Revelli
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Deon D Doree
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Christopher M DaCosta
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Urvi Desai
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Melanie K Shadoan
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Lawrence Rodriguez
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Michael Mullens
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Qi M Yang
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Zhi-Ming Ding
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Laura L Kirkpatrick
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Peter Vogel
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Brian Zambrowicz
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Arthur T Sands
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Kenneth A Platt
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Gwenn M Hansen
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Robert Brommage
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
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Ashraf UM, Mell B, Jose PA, Kumarasamy S. Deep transcriptomic profiling of Dahl salt-sensitive rat kidneys with mutant form of Resp18. Biochem Biophys Res Commun 2021; 572:35-40. [PMID: 34340197 DOI: 10.1016/j.bbrc.2021.07.071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 01/26/2023]
Abstract
Expression of Regulated endocrine specific protein 18 (Resp18) is localized in numerous tissues and cell types; however, its exact cellular function is unknown. We previously showed that targeted disruption of the Resp18 locus in the Dahl SS (SS) rat (Resp18mutant) results in higher blood pressure (BP), increased renal fibrosis, increased urinary protein excretion, and decreased mean survival time following a chronic (6 weeks) 2% high salt (HS) diet compared with the SS rat. Based on this prominent renal injury phenotype, we hypothesized that targeted disruption of Resp18 in the SS rat promotes an early onset hypertensive-signaling event through altered signatures of the renal transcriptome in response to HS. To test this hypothesis, both SS and Resp18mutant rats were exposed to a 7-day 2% HS diet and BP was recorded by radiotelemetry. After a 7-day exposure to the HS diet, systolic BP was significantly increased in the Resp18mutant rat compared with the SS rat throughout the circadian cycle. Therefore, we sought to investigate the renal transcriptomic response to HS in the Resp18mutant rat. Using RNA sequencing, Resp18mutant rats showed a differential expression of 25 renal genes, including upregulation of Ren. Upregulation of renal Ren and other differentially expressed genes were confirmed via qRT-PCR. Moreover, circulating renin activity was significantly higher in the Resp18mutant rat compared with the WT SS rat after 7 days on HS. Collectively, these observations demonstrate that disruption of the Resp18 gene in the SS rat is associated with an altered renal transcriptomics signature as an early response to salt load.
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Affiliation(s)
- Usman M Ashraf
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA
| | - Blair Mell
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA
| | - Pedro A Jose
- Department of Medicine, Division of Kidney Diseases & Hypertension, The George Washington University School of Medicine & Health Sciences, Washington, DC, 20052, USA; Department of Pharmacology and Physiology, The George Washington University School of Medicine & Health Sciences, Washington, DC, 20052, USA
| | - Sivarajan Kumarasamy
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA; Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA; Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701, USA.
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Narud B, Khezri A, Zeremichael TT, Stenseth EB, Heringstad B, Johannisson A, Morrell JM, Collas P, Myromslien FD, Kommisrud E. Sperm chromatin integrity and DNA methylation in Norwegian Red bulls of contrasting fertility. Mol Reprod Dev 2021; 88:187-200. [PMID: 33634579 DOI: 10.1002/mrd.23461] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/18/2021] [Accepted: 02/10/2021] [Indexed: 12/28/2022]
Abstract
In this study, the complexity of chromatin integrity was investigated in frozen-thawed semen samples from 37 sires with contrasting fertility, expressed as 56-day non-return rates (NR56). Protamine deficiency, thiols, and disulfide bonds were assessed and compared with previously published data for DNA fragmentation index (DFI) and high DNA stainability (HDS). In addition, in vitro embryo development and sperm DNA methylation were assessed using semen samples from 16 of these bulls. The percentages of DFI and HDS were negatively associated with NR56 and cleavage rate and positively associated with sperm protamine deficiency (p < 0.05). Significant differences in cleavage and blastocyst rates were observed between bulls of high and low NR56. However, once fertilization occurred, further development into blastocysts was not associated with NR56. The differential methylation analysis showed that spermatozoa from bulls of low NR56 were hypermethylated compared to bulls of high NR56. Pathway analysis showed that genes annotated to differentially methylated cytosines could participate in different biological pathways and have important biological roles related to bull fertility. In conclusion, sperm cells from Norwegian Red bulls of inferior fertility have less compact chromatin structure, higher levels of DNA damage, and are hypermethylated compared with bulls of superior fertility.
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Affiliation(s)
- Birgitte Narud
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Biotechnology, Inland Norway University of Applied Sciences, Hamar, Norway
| | - Abdolrahman Khezri
- Department of Biotechnology, Inland Norway University of Applied Sciences, Hamar, Norway
| | | | - Else-Berit Stenseth
- Department of Biotechnology, Inland Norway University of Applied Sciences, Hamar, Norway
| | - Bjørg Heringstad
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Anders Johannisson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jane M Morrell
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | | | - Elisabeth Kommisrud
- Department of Biotechnology, Inland Norway University of Applied Sciences, Hamar, Norway
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