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Pi M, Agarwal R, Smith MD, Smith JC, Quarles LD. GPRC6A is a Potential Therapeutic Target for Metformin Regulation of Glucose Homeostasis in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.19.608635. [PMID: 39229180 PMCID: PMC11370357 DOI: 10.1101/2024.08.19.608635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Understanding the mechanism of metformin actions in treating type 2 diabetes is limited by an incomplete knowledge of the specific protein targets mediating its metabolic effects. Metformin has structural similarities to L-Arginine (2-amino-5-guanidinopentanoic acid), which is a ligand for GPRC6A, a Family C G-protein coupled receptor that regulates energy metabolism. Ligand activation of GPRC6A results in lowering of blood glucose and other metabolic changes resembling the therapeutic effect of metformin. In the current study, we tested if metformin activates GPRC6A. We used Alphafold2 to develop a structural model for L-Arginine (L-Arg) binding to the extracellu-lar bilobed venus flytrap domain (VFT) of GPRC6A. We found that metformin docked to the site in the VFT that overlaps the binding site for L-Arg. Metformin resulted in a dose-dependent stimulation of GPRC6A activity in HEK-293 cells transfected with full-length wild-type GPRC6A but not in untransfected control cells. In addition, metformin failed to activate an alternatively spliced GPRC6A isoform lacking the putative binding site in the VFT. More specifically, mutation of the predicted metformin key binding residues Glu170 and Asp303 in the GPRC6A VFT resulted in loss of metformin receptor activation in vitro. The in vivo role of GPRC6A in mediating the effects of metformin was tested in Gprc6a-/- mice. Administration of therapeutic doses of metformin lowered blood glucose levels following a glucose tolerance test in wild-type but not Gprc6a-/- mice. Finally, we EN300, created by adding a carboxymethyl group from L-Arg to the biguanide backbone of metformin. EN300 showed dose-dependent stimulation of GPRC6A activity in vitro with greater potency than L-Arginine, but less than metformin. Thus, we suggest that GPRC6A is a potential molecular target for metformin which may be used to understand the therapeutic actions of metformin and develop novel small molecules to treat T2D.
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Affiliation(s)
- Min Pi
- Departments of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Rupesh Agarwal
- University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge, Tennessee 37830
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Micholas Dean Smith
- University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge, Tennessee 37830
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Jeremy C. Smith
- University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge, Tennessee 37830
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - L. Darryl Quarles
- Departments of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163
- Oak Ridge Therapeutic Discovery, LLC, Memphis, Tennessee 38137
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Paracha N, Mastrokostas P, Kello E, Gedailovich Y, Segall D, Rizzo A, Mitelberg L, Hassan N, Dowd TL. Osteocalcin improves glucose tolerance, insulin sensitivity and secretion in older male mice. Bone 2024; 182:117048. [PMID: 38378083 DOI: 10.1016/j.bone.2024.117048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/19/2024] [Accepted: 02/09/2024] [Indexed: 02/22/2024]
Abstract
Osteocalcin deficient mice (OC-/-), on a mixed 129/BL6J background, were reported to show glucose intolerance, insulin insensitivity and reduced insulin secretion at 1-6 mos of age. This is controversial as two studies in OC-/- mice on different backgrounds (C3H/BL6 (5-6 mos.) and C57BL/6N (5 and 9 mos.)) found no effect on glucose metabolism. To determine the role of OC in glucose metabolism we conducted glucose tolerance tests (GTT), insulin tolerances tests (ITT) and glucose stimulated insulin secretion (GSIS) on 6 and 9.5 month-old male OC-/- and OC+/+ mice on a pure C57BL/6J background and fed a normal chow diet. All results were analyzed with a two-way repeated measures ANOVA. The GTT results showed no effect on males at 6 months of age but glucose intolerance was significantly increased (p < 0.05) in male OC-/- mice at 9.5 months of age. The ITT results indicated significantly increased insulin resistance in male OC-/- mice. Glucose stimulated insulin secretion (GSIS) showed insulin significantly (p < 0.05) reduced in OC-/- at several time points. Mouse Osteocalcin injected into OC-/- mice decreased the glucose level. Our results confirm the role of OC in glucose metabolism and insulin sensitivity and demonstrate a role in insulin secretion in older male mice on a C57BL/6J background. Differences in background, age, or experimental procedures could explain controversial results. A delayed onset of the effect of OC on glucose metabolism at 9.5 months in male C57BL/6J mice highlights the importance of background on phenotype. Consideration of genetic background and age may be beneficial for human studies on osteocalcin and glucose homeostasis and may be relevant to the elderly where osteocalcin is reduced.
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Affiliation(s)
- Noorulain Paracha
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Paul Mastrokostas
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Evan Kello
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Yosef Gedailovich
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Devorah Segall
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Alexis Rizzo
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Lawrence Mitelberg
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Naif Hassan
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Terry Lynne Dowd
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America; Ph.D. Program in Chemistry and Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America.
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Khosla S. Evidence in Humans for Bone as an Endocrine Organ Regulating Energy Metabolism. CURRENT OPINION IN ENDOCRINE AND METABOLIC RESEARCH 2023; 31:100471. [PMID: 37576432 PMCID: PMC10417886 DOI: 10.1016/j.coemr.2023.100471] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
There is increasing evidence from animal models that bone, in addition to its traditional function of providing structural support for the organism, has a rich network of interactions with multiple other tissues. This perspective focuses on evidence from human studies demonstrating that bone is an endocrine organ regulating energy metabolism, with the specific examples being osteocalcin, lipocalin 2, RANKL, and sclerostin. Conversely, animal studies have also demonstrated that a key hormone regulating energy metabolism, leptin, regulates bone metabolism via the sympathetic nervous system. Studies in humans have established a role for the sympathetic nervous system in regulating bone turnover; indeed, the potential therapeutic benefit of targeting this pathway in humans to prevent postmenopausal bone loss is currently being evaluated.
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Affiliation(s)
- Sundeep Khosla
- Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota
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Jawich K, Rocca MS, Al Fahoum S, Alhalabi M, Di Nisio A, Foresta C, Ferlin A, De Toni L. RS 2247911 polymorphism of GPRC6A gene and serum undercarboxylated-osteocalcin are associated with testis function. J Endocrinol Invest 2022; 45:1673-1682. [PMID: 35482214 DOI: 10.1007/s40618-022-01803-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/07/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE Undercarboxylated-Osteocalcin (ucOCN), acting on its putative receptor GPRC6A, was shown to stimulate testosterone (T) production by Leydig cells in rodents, in parallel with the hypothalamus-pituitary-gonadal axis (HPG) mediated by luteinizing hormone (LH). The aim of this cross-sectional study was to evaluate the association among serum ucOCN, rs2247911 polymorphism of GPRC6A gene and the endocrine/semen pattern in a cohort of infertile males, possibly identifying an involvement of the ucOCN-GPRC6A axis on testis function. METHODS 190 males, including 74 oligozoospermic subjects, 58 azoosperminc patients and 58 normozoospermic controls, were prospectively recruited at the Orient Hospital for Infertility, Assisted Reproduction and Genetics in Syria (Study N. 18FP), from July 2018 to June 2020. Outpatient evaluation included the clinical history, anthropometrics and a fasting blood sampling for hormonals, serum OCN (both carboxylated and undercarboxylated), glycemic and lipid profile and screening for rs2247911 GPRC6A gene polymorphism. RESULTS Higher serum ucOCN associated with higher T and HDL-cholesterol (respectively: r = 0.309, P < 0.001 and r = 0.248, P = 0.001), and with lower FSH (r = - 0.327, P < 0.001) and LDL-cholesterol (r = - 0.171; P = 0.018). Patients bearing the GG genotype of rs2247911 had higher sperm count compared to GA genotype (P = 0.043) and, compared to both AG and AA genotypes, had higher serum T (P = 0.004, P = 0.001) and lower triglycerides levels (P = 0.002, P < 0.001). Upon normalization for LH levels and body mass index, rs2274911 and ucOCN were significantly associated with higher serum T at linear stepwise regression analysis (P = 0.013, P = 0.007). CONCLUSIONS Our data suggest the involvement of ucOCN-GPRC6A axis in the regulation of T production by the testis, subsidiary to HPG.
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Affiliation(s)
- K Jawich
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syrian Arab Republic
| | - M Santa Rocca
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padua, Italy
- Unit of Andrology and Reproductive Medicine, University Hospital of Padova, Padua, Italy
| | - S Al Fahoum
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syrian Arab Republic.
| | - M Alhalabi
- Department of Embryology and Reproductive Medicine, Faculty of Medicine, Damascus University, Damascus, Syrian Arab Republic
| | - A Di Nisio
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padua, Italy
| | - C Foresta
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padua, Italy
| | - A Ferlin
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padua, Italy
| | - L De Toni
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padua, Italy
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Berger JM, Karsenty G. Osteocalcin and the Physiology of Danger. FEBS Lett 2021; 596:665-680. [PMID: 34913486 PMCID: PMC9020278 DOI: 10.1002/1873-3468.14259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 12/02/2022]
Abstract
Bone biology has long been driven by the question as to what molecules affect cell differentiation or the functions of bone. Exploring this issue has been an extraordinarily powerful way to improve our knowledge of bone development and physiology. More recently, a second question has emerged: does bone have other functions besides making bone? Addressing this conundrum revealed that the bone-derived hormone osteocalcin affects a surprisingly large number of organs and physiological processes, including acute stress response. This review will focus on this emerging aspect of bone biology taking osteocalcin as a case study and will show how classical and endocrine functions of bone help to define a new functional identity for this tissue.
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Affiliation(s)
- Julian Meyer Berger
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, NY, 10032, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, NY, 10032, USA
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Pi M, Nishimoto SK, Darryl Quarles L. Explaining Divergent Observations Regarding Osteocalcin/GPRC6A Endocrine Signaling. Endocrinology 2021; 162:6104945. [PMID: 33474566 PMCID: PMC7880225 DOI: 10.1210/endocr/bqab011] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Indexed: 12/13/2022]
Abstract
A new schema proposes that the bone-derived osteocalcin (Ocn) peptide hormone activates the G-protein-coupled receptor GPRC6A to directly regulate glucose and fat metabolism in liver, muscle, and fat, and to stimulate the release of metabolism-regulating hormones, including insulin, fibroblast growth factor 21, glucagon-like peptide 1, testosterone, and interleukin 6. Ocn/GPRC6A activation has also been implicated in cancer progression. GPRC6A is activated by cations, amino acids, and testosterone. The multiligand specificity, the regulation of energy metabolism in diverse tissues, and the coordinated release of metabolically active hormones make the GPRC6A endocrine networks unique. Recently, the significance of Ocn/GPRCA has been questioned. There is a lack of metabolic abnormalities in newly created genetically engineered Ocn- and Gprc6a-deficient mouse models. There are also paradoxical observations that GPRC6A may function as a tumor suppressor. In addition, discordant published studies have cast doubt on the function of the most prevalent uniquely human GPRC6A-KGKY polymorphism. Explanations for these divergent findings are elusive. We provide evidence that the metabolic susceptibility of genetically engineered Ocn- and Gprc6a-deficient mice is influenced by environmental challenges and genetic differences in mouse strains. In addition, the GPRC6A-KGKY polymorphism appears to be a gain-of-function variant. Finally, alternatively spliced isoforms of GPRC6A may alter ligand specificity and signaling that modulate oncogenic effects. Thus, genetic, post-translational and environmental factors likely account for the variable results regarding the functions of GPRC6A in animal models. Pending additional information, GPRC6A should remain a potential therapeutic target for regulating energy and fat metabolism, hormone production, and cancer progression.
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Affiliation(s)
- Min Pi
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Satoru Kenneth Nishimoto
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - L Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
- Correspondence: L. Darryl Quarles, MD, University of Tennessee Health Sciences Center, Memphis, TN, USA. . Current Affiliation: 965 Court Ave, Suite B226, Memphis, TN 38163, USA
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Qi N, Chen Y, Zeng Y, Bao M, Long X, Guo Y, Tan A, Gao Y, Zhang H, Yang X, Hu Y, Mo Z, Jiang Y. rs2274911 polymorphism in GPRC6A associated with serum E2 and PSA in a Southern Chinese male population. Gene 2020; 763:145067. [PMID: 32827681 DOI: 10.1016/j.gene.2020.145067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/03/2020] [Accepted: 08/17/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND rs2274911 (Pro91Ser, G > A) is a missense mutation located on the second exon of the GPRC6A gene. Increasing evidence revealed a significant association between the A allele of rs2274911 and male diseases, such as oligospermia, cryptorchidism, and prostate tumor. However, the function of rs2274911 in healthy males is unclear. SUBJECTS AND METHODS A total of 1742 healthy men were selected from the Fangchenggang Area Male Health and Examination Survey (FAMHES). The association between rs2274911 and phenotype was evaluated. The cell characteristics of rs2274911 mutation (mu), wild-type GPRC6A (WT), and RFP control in human embryonic kidney (293T) and human prostate cancer (PC3) cells were analyzed. RNA sequencing was performed on PC3 cells. RESULTS E2 and PSA serum levels increased with the accumulation of the A allele (E2: G vs. A, -0.029 [-0.050, -0.008], P < 0.01, P trend = 0.027; PSA: G vs. A, -0.040 [-0.079, 0.000], P < 0.05, P trend = 0.048). rs2274911 enhanced the proliferation and invasion ability of PC3 or 293T cells and activated the ERK pathway. The genes were identified as rs2274911 mu-affected genes through RNA sequential analysis of rs2274911 mu, GPRC6A WT, and RFP control of PC3 cells. Most of these genes were related to cancer development processes, cAMP, and the ERK cell signaling pathway. CONCLUSION This project represents that rs2274911 is associated with E2 and PSA serum levels in Southern Chinese men. Rs2274991 mutation promotes 293T and PC3 cell proliferation in vitro. These results suggest that rs2274911 is a functional variant of GPRC6A.
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Affiliation(s)
- Nana Qi
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China
| | - Yang Chen
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Department of Urology Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Yanyu Zeng
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China
| | - Mengying Bao
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China
| | - Xinyang Long
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China
| | - Yajie Guo
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China
| | - Aihua Tan
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Department of Chemotherapy, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Yong Gao
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Haiying Zhang
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Department of Occupational Health and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Xiaobo Yang
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Department of Occupational Health and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Yanling Hu
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China
| | - Zengnan Mo
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Department of Urology Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, China.
| | - Yonghua Jiang
- Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, Guangxi 530021, China; Guangxi Key Laboratory of Genomic and Personalized Medicine, Nanning, Guangxi 530021, China; Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Nanning, Guangxi 530021, China.
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Al Rifai O, Julien C, Lacombe J, Faubert D, Lira-Navarrete E, Narimatsu Y, Clausen H, Ferron M. The half-life of the bone-derived hormone osteocalcin is regulated through O-glycosylation in mice, but not in humans. eLife 2020; 9:61174. [PMID: 33284103 PMCID: PMC7822592 DOI: 10.7554/elife.61174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/06/2020] [Indexed: 12/14/2022] Open
Abstract
Osteocalcin (OCN) is an osteoblast-derived hormone with pleiotropic physiological functions. Like many peptide hormones, OCN is subjected to post-translational modifications (PTMs) which control its activity. Here, we uncover O-glycosylation as a novel PTM present on mouse OCN and occurring on a single serine (S8) independently of its carboxylation and endoproteolysis, two other PTMs regulating this hormone. We also show that O-glycosylation increases OCN half-life in plasma ex vivo and in the circulation in vivo. Remarkably, in human OCN (hOCN), the residue corresponding to S8 is a tyrosine (Y12), which is not O-glycosylated. Yet, the Y12S mutation is sufficient to O-glycosylate hOCN and to increase its half-life in plasma compared to wildtype hOCN. These findings reveal an important species difference in OCN regulation, which may explain why serum concentrations of OCN are higher in mouse than in human. Bones provide support and protection for organs in the body. However, over the last 15 years researchers have discovered that bones also release chemicals known as hormones, which can travel to other parts of the body and cause an effect. The cells responsible for making bone, known as osteoblasts, produce a hormone called osteocalcin which communicates with a number of different organs, including the pancreas and brain. When osteocalcin reaches the pancreas, it promotes the release of another hormone called insulin which helps regulate the levels of sugar in the blood. Osteocalcin also travels to other organs such as muscle, where it helps to degrade fats and sugars that can be converted into energy. It also has beneficial effects on the brain, and has been shown to aid memory and reduce depression. Osteocalcin has largely been studied in mice where levels are five to ten times higher than in humans. But it is unclear why this difference exists or how it alters the role of osteocalcin in humans. To answer this question, Al Rifai et al. used a range of experimental techniques to compare the structure and activity of osteocalcin in mice and humans. The experiments showed that mouse osteocalcin has a group of sugars attached to its protein structure, which prevent the hormone from being degraded by an enzyme in the blood. Human osteocalcin has a slightly different protein sequence and is therefore unable to bind to this sugar group. As a result, the osteocalcin molecules in humans are less stable and cannot last as long in the blood. Al Rifai et al. showed that when human osteocalcin was modified so the sugar group could attach, the hormone was able to stick around for much longer and reach higher levels when added to blood in the laboratory. These findings show how osteocalcin differs between human and mice. Understanding this difference is important as the effects of osteocalcin mean this hormone can be used to treat diabetes and brain disorders. Furthermore, the results reveal how the stability of osteocalcin could be improved in humans, which could potentially enhance its therapeutic effect.
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Affiliation(s)
- Omar Al Rifai
- Molecular Physiology Research unit, Institut de Recherches Cliniques de Montréal, Montréal, Canada.,Programme de biologie moléculaire, Université de Montréal, Montréal, Canada
| | - Catherine Julien
- Molecular Physiology Research unit, Institut de Recherches Cliniques de Montréal, Montréal, Canada
| | - Julie Lacombe
- Molecular Physiology Research unit, Institut de Recherches Cliniques de Montréal, Montréal, Canada
| | - Denis Faubert
- Proteomics Discovery Platform, Institut de Recherches Cliniques de Montréal, Montréal, Canada
| | - Erandi Lira-Navarrete
- University of Copenhagen, Faculty of Health Sciences, Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Copenhagen, Denmark
| | - Yoshiki Narimatsu
- University of Copenhagen, Faculty of Health Sciences, Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Copenhagen, Denmark
| | - Henrik Clausen
- University of Copenhagen, Faculty of Health Sciences, Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Copenhagen, Denmark
| | - Mathieu Ferron
- Molecular Physiology Research unit, Institut de Recherches Cliniques de Montréal, Montréal, Canada.,Programme de biologie moléculaire, Université de Montréal, Montréal, Canada.,Département de Médecine, Université de Montréal, Montréal, Canada.,Division of Experimental Medicine, McGill University, Montréal, Canada
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9
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Ducy P. Bone Regulation of Insulin Secretion and Glucose Homeostasis. Endocrinology 2020; 161:5895464. [PMID: 32822470 DOI: 10.1210/endocr/bqaa149] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/18/2020] [Indexed: 12/31/2022]
Abstract
For centuries our image of the skeleton has been one of an inert structure playing a supporting role for muscles and a protective role for inner organs like the brain. Cell biology and physiology modified this view in the 20st century by defining the constant interplay between bone-forming and bone resorbing cells that take place during bone growth and remodeling, therefore demonstrating that bone is as alive as any other tissues in the body. During the past 40 years human and, most important, mouse genetics, have allowed not only the refinement of this notion by identifying the many genes and regulatory networks responsible for the crosstalk existing between bone cells, but have redefined the role of bone by showing that its influence goes way beyond its own physiology. Among its newly identified functions is the regulation of energy metabolism by 2 bone-derived hormones, osteocalcin and lipocalin-2. Their biology and respective roles in this process are the topic of this review.
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Affiliation(s)
- Patricia Ducy
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, College of Physicians and Surgeons, New York, New York
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10
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Kaune T, Ruffert C, Hesselbarth N, Damm M, Krug S, Cardinal von Widdern J, Masson E, Chen JM, Rebours V, Buscail L, Férec C, Grützmann R, Te Morsche RHM, Drenth JP, Cavestro GM, Zuppardo RA, Saftoiu A, Malecka-Panas E, Głuszek S, Bugert P, Lerch MM, Sendler M, Weiss FU, Zou WB, Deng SJ, Liao Z, Scholz M, Kirsten H, Hegyi P, Witt H, Michl P, Griesmann H, Rosendahl J. Analysis of GPRC6A variants in different pancreatitis etiologies. Pancreatology 2020; 20:1262-1267. [PMID: 32859544 DOI: 10.1016/j.pan.2020.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/09/2020] [Accepted: 08/02/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND The G-protein-coupled receptor Class C Group 6 Member A (GPRC6A) is activated by multiple ligands and is important for the regulation of calcium homeostasis. Extracellular calcium is capable to increase NLRP3 inflammasome activity of the innate immune system and deletion of this proinflammatory pathway mitigated pancreatitis severity in vivo. As such this pathway and the GPRC6A receptor is a reasonable candidate gene for pancreatitis. Here we investigated the prevalence of sequence variants in the GPRC6A locus in different pancreatitis aetiologies. METHODS We selected 6 tagging SNPs with the SNPinfo LD TAG SNP Selection tool and the functional relevant SNP rs6907580 for genotyping. Cohorts from Germany, further European countries and China with up to 1,124 patients and 1,999 controls were screened for single SNPs with melting curve analysis. RESULTS We identified an association of rs1606365(G) with alcoholic chronic pancreatitis in a German (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.65-0.89, p = 8 × 10-5) and a Chinese cohort (OR 0.78, 95% CI 0.64-0.96, p = 0.02). However, this association was not replicated in a combined cohort of European patients (OR 1.18, 95% CI 0.99-1.41, p = 0.07). Finally, no association was found with acute and non-alcoholic chronic pancreatitis. CONCLUSIONS Our results support a potential role of calcium sensing receptors and inflammasome activation in alcoholic chronic pancreatitis development. As the functional consequence of the associated variant is unclear, further investigations might elucidate the relevant mechanisms.
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Affiliation(s)
- Tom Kaune
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | - Claudia Ruffert
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | - Nico Hesselbarth
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | - Marko Damm
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | - Sebastian Krug
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | | | - Emmanuelle Masson
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France; CHRU Brest, Service de Génétique Médicale et de Biologie de la Reproduction, Brest, France
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Vinciane Rebours
- Department of Gastroenterology and Pancreatology, Beaujon Hospital, APHP, Clichy, and Paris-Diderot University, Paris, France
| | - Louis Buscail
- Service de Gastroentérologie et Pancréatologie, CHU Toulouse, Toulouse, France
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France; CHRU Brest, Service de Génétique Médicale et de Biologie de la Reproduction, Brest, France
| | - Robert Grützmann
- Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Chirurgische Klinik, Erlangen, Germany
| | - Rene H M Te Morsche
- Department of Gastroenterology and Hepatology, Radboud umc, Nijmegen, the Netherlands
| | - Joost Ph Drenth
- Department of Gastroenterology and Hepatology, Radboud umc, Nijmegen, the Netherlands
| | - Giulia Martina Cavestro
- Gastroenterology and Gastrointestinal Endoscopy Unit, Division of Experimental Oncology, Vita-Salute San Raffaele University, IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Raffaella Alessia Zuppardo
- Gastroenterology and Gastrointestinal Endoscopy Unit, Division of Experimental Oncology, Vita-Salute San Raffaele University, IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Adrian Saftoiu
- Department of Internal Medicine and Gastroenterology, University of Medicine and Pharmacy, Craiova, Romania
| | - Ewa Malecka-Panas
- Department of Digestive Tract Diseases, Medical University of Łódź, Łódź, Poland
| | - Stanislaw Głuszek
- Collegium Medicum (Medical College), Jan Kochanowski University, Kielce, Poland
| | - Peter Bugert
- Institute of Transfusion Medicine and Immunology, Medical Faculty Mannheim, Heidelberg University, German Red Cross Blood Service of Baden-Württemberg, Mannheim, Germany
| | - Markus M Lerch
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Matthias Sendler
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Frank Ulrich Weiss
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Wen-Bin Zou
- Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, Shanghai, China; Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Shun-Jiang Deng
- Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, Shanghai, China; Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Zhuan Liao
- Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, Shanghai, China; Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Markus Scholz
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany; LIFE- Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany
| | - Holger Kirsten
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany; LIFE- Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany
| | - Peter Hegyi
- Institute for Translational Medicine and First Department of Internal Medicine, Medical School, University of Pécs, Pécs, Hungary; First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Heiko Witt
- Else Kröner-Fresenius-Zentrum für Ernährungsmedizin (EKFZ), Paediatric Nutritional Medicine, Technische Universität München (TUM), Freising, Germany
| | - Patrick Michl
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | - Heidi Griesmann
- Department of Internal Medicine I, Martin Luther University, Halle, Germany
| | - Jonas Rosendahl
- Department of Internal Medicine I, Martin Luther University, Halle, Germany.
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11
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Pi M, Xu F, Ye R, Nishimoto SK, Kesterson RA, Williams RW, Lu L, Quarles LD. Humanized GPRC6A KGKY is a gain-of-function polymorphism in mice. Sci Rep 2020; 10:11143. [PMID: 32636482 PMCID: PMC7341878 DOI: 10.1038/s41598-020-68113-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 05/29/2020] [Indexed: 12/18/2022] Open
Abstract
GPRC6A is proposed to regulate energy metabolism in mice, but in humans a KGKY polymorphism in the third intracellular loop (ICL3) is proposed to result in intracellular retention and loss-of-function. To test physiological importance of this human polymorphism in vivo, we performed targeted genomic humanization of mice by using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats-CRISPR associated protein 9) system to replace the RKLP sequence in the ICL3 of the GPRC6A mouse gene with the uniquely human KGKY sequence to create Gprc6a-KGKY-knockin mice. Knock-in of a human KGKY sequence resulted in a reduction in basal blood glucose levels and increased circulating serum insulin and FGF-21 concentrations. Gprc6a-KGKY-knockin mice demonstrated improved glucose tolerance, despite impaired insulin sensitivity and enhanced pyruvate-mediated gluconeogenesis. Liver transcriptome analysis of Gprc6a-KGKY-knockin mice identified alterations in glucose, glycogen and fat metabolism pathways. Thus, the uniquely human GPRC6A-KGKY variant appears to be a gain-of-function polymorphism that positively regulates energy metabolism in mice.
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Affiliation(s)
- Min Pi
- Department of Medicine, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA.
| | - Fuyi Xu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA
| | - Ruisong Ye
- Department of Medicine, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA
| | - Satoru K Nishimoto
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, 720 20th Street South, Birmingham, AL, 35294, USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA
| | - L Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, 19 S Manassas St., Memphis, TN, 38163, USA.
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12
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Karsenty G. The facts of the matter: What is a hormone? PLoS Genet 2020; 16:e1008938. [PMID: 32589668 PMCID: PMC7319275 DOI: 10.1371/journal.pgen.1008938] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 06/17/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Gerard Karsenty
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, New York, United States of America
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13
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Lin X, Onda DA, Yang CH, Lewis JR, Levinger I, Loh K. Roles of bone-derived hormones in type 2 diabetes and cardiovascular pathophysiology. Mol Metab 2020; 40:101040. [PMID: 32544571 PMCID: PMC7348059 DOI: 10.1016/j.molmet.2020.101040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/28/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
Background Emerging evidence demonstrates that bone is an endocrine organ capable of influencing multiple physiological and pathological processes through the secretion of hormones. Recent research suggests complex crosstalk between the bone and other metabolic and cardiovascular tissues. It was uncovered that three of these bone-derived hormones—osteocalcin, lipocalin 2, and sclerostin—are involved in the endocrine regulations of cardiometabolic health and play vital roles in the pathophysiological process of developing cardiometabolic syndromes such as type 2 diabetes and cardiovascular disease. Chronic low-grade inflammation is one of the hallmarks of cardiometabolic diseases and a major contributor to disease progression. Novel evidence also implicates important roles of bone-derived hormones in the regulation of chronic inflammation. Scope of review In this review, we provide a detailed overview of the physiological and pathological roles of osteocalcin, lipocalin 2, and sclerostin in cardiometabolic health regulation and disease development, with a focus on the modulation of chronic inflammation. Major conclusions Evidence supports that osteocalcin has a protective role in cardiometabolic health, and an increase of lipocalin 2 contributes to the development of cardiometabolic diseases partly via pro-inflammatory effects. The roles of sclerostin appear to be complicated: It exerts pro-adiposity and pro-insulin resistance effects in type 2 diabetes and has an anti-calcification effect during cardiovascular disease. A better understanding of the actions of these bone-derived hormones in the pathophysiology of cardiometabolic diseases will provide crucial insights to help further research develop new therapeutic strategies to treat these diseases.
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Affiliation(s)
- Xuzhu Lin
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia.
| | - Danise-Ann Onda
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - Chieh-Hsin Yang
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - Joshua R Lewis
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia; Medical School, University of Western Australia, Perth, Australia
| | - Itamar Levinger
- Institute for Health and Sport (IHES), Victoria University, Footscray, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Kim Loh
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia; Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
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14
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Jørgensen CV, Bräuner‐Osborne H. Pharmacology and physiological function of the orphan GPRC6A receptor. Basic Clin Pharmacol Toxicol 2020; 126 Suppl 6:77-87. [DOI: 10.1111/bcpt.13397] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Christinna V. Jørgensen
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Hans Bräuner‐Osborne
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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15
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Lacombe J, Al Rifai O, Loter L, Moran T, Turcotte AF, Grenier-Larouche T, Tchernof A, Biertho L, Carpentier AC, Prud'homme D, Rabasa-Lhoret R, Karsenty G, Gagnon C, Jiang W, Ferron M. Measurement of bioactive osteocalcin in humans using a novel immunoassay reveals association with glucose metabolism and β-cell function. Am J Physiol Endocrinol Metab 2020; 318:E381-E391. [PMID: 31935114 PMCID: PMC7395472 DOI: 10.1152/ajpendo.00321.2019] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Osteocalcin (OCN) is a bone-derived hormone involved in the regulation of glucose metabolism. In serum, OCN exists in carboxylated and uncarboxylated forms (ucOCN), and studies in rodents suggest that ucOCN is the bioactive form of this hormone. Whether this is also the case in humans is unclear, because a reliable assay to measure ucOCN is not available. Here, we established and validated a new immunoassay (ELISA) measuring human ucOCN and used it to determine the level of bioactive OCN in two cohorts of overweight or obese subjects, with or without type 2 diabetes (T2D). The ELISA could specifically detect ucOCN concentrations ranging from 0.037 to 1.8 ng/mL. In a first cohort of overweight or obese postmenopausal women without diabetes (n = 132), ucOCN correlated negatively with fasting glucose (r = -0.18, P = 0.042) and insulin resistance assessed by the homeostatic model assessment of insulin resistance (r = -0.18, P = 0.038) and positively with insulin sensitivity assessed by a hyperinsulinemic-euglycemic clamp (r = 0.18, P = 0.043) or insulin sensitivity index derived from an oral glucose tolerance test (r = 0.26, P = 0.003). In a second cohort of subjects with severe obesity (n = 16), ucOCN was found to be lower in subjects with T2D compared with those without T2D (2.76 ± 0.38 versus 4.52 ± 0.06 ng/mL, P = 0.009) and to negatively correlate with fasting glucose (r = -0.50, P = 0.046) and glycated hemoglobin (r = -0.57, P = 0.021). Moreover, the subjects with ucOCN levels below 3 ng/mL had a reduced insulin secretion rate during a hyperglycemic clamp (P = 0.03). In conclusion, ucOCN measured with this novel and specific assay is inversely associated with insulin resistance and β-cell dysfunction in humans.
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Affiliation(s)
- Julie Lacombe
- Unité de Recherche en Physiologie Moléculaire, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada
| | - Omar Al Rifai
- Unité de Recherche en Physiologie Moléculaire, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada
- Department of Medicine, Université de Montréal, Québec, Canada
| | | | - Thomas Moran
- Center for Therapeutic Antibody Development, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Anne-Frédérique Turcotte
- Endocrinology and Nephrology Unit, CHU de Québec-Université Laval Research Center, Québec City, Québec, Canada
| | - Thomas Grenier-Larouche
- Québec Heart and Lung Institute Research Centre, Québec City, Québec, Canada
- Service d'Endocrinologie, Département de Médecine, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - André Tchernof
- Québec Heart and Lung Institute Research Centre, Québec City, Québec, Canada
| | - Laurent Biertho
- Québec Heart and Lung Institute Research Centre, Québec City, Québec, Canada
| | - André C Carpentier
- Service d'Endocrinologie, Département de Médecine, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Denis Prud'homme
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
- Institut du Savoir Montfort, Ottawa, Ontario, Canada
| | - Rémi Rabasa-Lhoret
- Département de Nutrition, Université de Montréal, Montréal, Québec, Canada
- Unité de Recherche en Maladies Métaboliques, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University Medical Center, New York, New York
| | - Claudia Gagnon
- Endocrinology and Nephrology Unit, CHU de Québec-Université Laval Research Center, Québec City, Québec, Canada
- Québec Heart and Lung Institute Research Centre, Québec City, Québec, Canada
- Department of Medicine, Université Laval, Québec City, Québec, Canada
| | | | - Mathieu Ferron
- Unité de Recherche en Physiologie Moléculaire, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada
- Department of Medicine, Université de Montréal, Québec, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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16
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Ye R, Pi M, Nooh MM, Bahout SW, Quarles LD. Human GPRC6A Mediates Testosterone-Induced Mitogen-Activated Protein Kinases and mTORC1 Signaling in Prostate Cancer Cells. Mol Pharmacol 2019; 95:563-572. [PMID: 30894404 DOI: 10.1124/mol.118.115014] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 03/06/2019] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled receptor family C group 6 member A (GPRC6A) is activated by testosterone and modulates prostate cancer progression. Most humans have a GPRC6A variant that contains a recently evolved KGKY insertion/deletion in the third intracellular loop (ICL3) (designated as GPRC6AICL3_KGKY) that replaces the ancestral KGRKLP sequence (GPRC6AICL3_RKLP) present in all other species. In vitro assays purport that human GPRC6AICL3_KGKY is retained intracellularly and lacks function. These findings contrast with ligand-dependent activation and coupling to mammalian target of rapamycin complex 1 (mTORC1) signaling of endogenous human GPRC6AICL3_KGKY in PC-3 cells. To understand these discrepant results, we expressed mouse (mGPRC6AICL3_KGRKLP), human (hGPRC6AICL3_KGKY), and humanized mouse (mGPRC6AICL3_KGKY) GPRC6A into human embryonic kidney 293 cells. Our results demonstrate that mGPRC6AICL3_KGRKLP acts as a classic G protein-coupled receptor, which is expressed at the cell membrane and internalizes in response to ligand activation by testosterone. In contrast, hGPRC6AICL3_KGKY and humanized mouse mGPRC6AICL3_KGKY are retained intracellularly in ligand naive cells, yet exhibit β-arrestin-dependent signaling responses, mitogen-activated protein kinase [i.e., extracellular signal-regulated kinase (ERK)], and p70S6 kinase phosphorylation in response to testosterone, indicating that hGPRC6AICL3_KGKY is functional. Indeed, testosterone stimulates time- and dose-dependent activation of ERK, protein kinase B, and mTORC1 signaling in wild-type PC-3 cells that express endogenous GPRC6AICL3_KGKY In addition, testosterone stimulates GPRC6A-dependent cell proliferation in wild-type PC-3 cells and inhibits autophagy by activating mTORC1 effectors eukaryotic translation initiation factor 4E binding protein 1 and Unc-51 like autophagy activating kinase 1. Testosterone activation of GPRC6A has the obligate requirement for calcium in the incubation media. In contrast, in GPRC6A-deficient cells, the effect of testosterone to activate downstream signaling is abolished, indicating that human GPRC6A is required for mediating the effects of testosterone on cell proliferation and autophagy.
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Affiliation(s)
- Ruisong Ye
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - Min Pi
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - Mohammed M Nooh
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - Suleiman W Bahout
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - L Darryl Quarles
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
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17
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Diaz-Franco MC, Franco-Diaz de Leon R, Villafan-Bernal JR. Osteocalcin‑GPRC6A: An update of its clinical and biological multi‑organic interactions (Review). Mol Med Rep 2018; 19:15-22. [PMID: 30431093 PMCID: PMC6297736 DOI: 10.3892/mmr.2018.9627] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 09/26/2018] [Indexed: 12/14/2022] Open
Abstract
Osteocalcin is no longer regarded as a molecule exclusive to bone remodeling and osteogenesis, but as a hormone with manifold functions. The discovery of the interaction of osteocalcin with the G protein‑coupled receptor family C group 6‑member A (GPRC6A) receptor has accompanied the characterization of several roles that this peptide serves in body regulation and homeostasis. These roles include the modulation of memory in the brain, fertility in the testis, fat accumulation in the liver, incretins release in the intestine and adaptation to exercise in muscle, in addition to the well‑known effects on β‑cell proliferation, insulin release and adiponectin secretion. The aim of the present review was to provide a practical update of the multi‑organ effects that osteocalcin exerts through its interaction with GPRC6A and the clinical implications of this.
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18
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Mera P, Ferron M, Mosialou I. Regulation of Energy Metabolism by Bone-Derived Hormones. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a031666. [PMID: 28778968 DOI: 10.1101/cshperspect.a031666] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Like many other organs, bone can act as an endocrine organ through the secretion of bone-specific hormones or "osteokines." At least two osteokines are implicated in the control of glucose and energy metabolism: osteocalcin (OCN) and lipocalin-2 (LCN2). OCN stimulates the production and secretion of insulin by the pancreatic β-cells, but also favors adaptation to exercise by stimulating glucose and fatty acid (FA) utilization by the muscle. Both of these OCN functions are mediated by the G-protein-coupled receptor GPRC6A. In contrast, LCN2 influences energy metabolism by activating appetite-suppressing signaling in the brain. This action of LCN2 occurs through its binding to the melanocortin 4 receptor (MC4R) in the paraventricular nucleus of the hypothalamus (PVN) and ventromedial neurons of the hypothalamus.
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Affiliation(s)
- Paula Mera
- Columbia University Medical Center, New York, New York 10032
| | - Mathieu Ferron
- Institut de Recherches Cliniques de Montréal, Montréal, Quebec H2W 1R7, Canada
| | - Ioanna Mosialou
- Columbia University Medical Center, New York, New York 10032
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19
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Obri A, Khrimian L, Karsenty G, Oury F. Osteocalcin in the brain: from embryonic development to age-related decline in cognition. Nat Rev Endocrinol 2018; 14:174-182. [PMID: 29376523 PMCID: PMC5958904 DOI: 10.1038/nrendo.2017.181] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A remarkable, unexpected aspect of the bone-derived hormone osteocalcin is that it is necessary for both brain development and brain function in the mouse, as its absence results in a profound deficit in spatial learning and memory and an exacerbation of anxiety-like behaviour. The regulation of cognitive function by osteocalcin, together with the fact that its circulating levels decrease in midlife compared with adolescence in all species tested, raised the prospect that osteocalcin might be an anti-geronic hormone that could prevent age-related cognitive decline. As presented in this Review, recent data indicate that this is indeed the case and that osteocalcin is necessary for the anti-geronic activity recently ascribed to the plasma of young wild-type mice. The diversity and amplitude of the functions of osteocalcin in the brain, during development and postnatally, had long called for the identification of its receptor in the brain, which was also recently achieved. This Review presents our current understanding of the biology of osteocalcin in the brain, highlighting the bony vertebrate specificity of the regulation of cognitive function and pointing toward where therapeutic opportunities might exist.
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Affiliation(s)
- Arnaud Obri
- Department of Genetics and Development, Columbia University Medical Center, 701 W 168th St. Rm 1602, New York City, New York 10032, USA
| | - Lori Khrimian
- Department of Genetics and Development, Columbia University Medical Center, 701 W 168th St. Rm 1602, New York City, New York 10032, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University Medical Center, 701 W 168th St. Rm 1602, New York City, New York 10032, USA
| | - Franck Oury
- Institut Necker-Enfants Malades, CS 61431, Paris, France Institut National de la Santé et de la Recherche Médicale, U1151, F-75014 Paris, France Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
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Riddy DM, Delerive P, Summers RJ, Sexton PM, Langmead CJ. G Protein–Coupled Receptors Targeting Insulin Resistance, Obesity, and Type 2 Diabetes Mellitus. Pharmacol Rev 2017; 70:39-67. [DOI: 10.1124/pr.117.014373] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/13/2017] [Indexed: 12/18/2022] Open
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21
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Al Rifai O, Chow J, Lacombe J, Julien C, Faubert D, Susan-Resiga D, Essalmani R, Creemers JW, Seidah NG, Ferron M. Proprotein convertase furin regulates osteocalcin and bone endocrine function. J Clin Invest 2017; 127:4104-4117. [PMID: 28972540 DOI: 10.1172/jci93437] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 08/15/2017] [Indexed: 12/12/2022] Open
Abstract
Osteocalcin (OCN) is an osteoblast-derived hormone that increases energy expenditure, insulin sensitivity, insulin secretion, and glucose tolerance. The cDNA sequence of OCN predicts that, like many other peptide hormones, OCN is first synthesized as a prohormone (pro-OCN). The importance of pro-OCN maturation in regulating OCN and the identity of the endopeptidase responsible for pro-OCN cleavage in osteoblasts are still unknown. Here, we show that the proprotein convertase furin is responsible for pro-OCN maturation in vitro and in vivo. Using pharmacological and genetic experiments, we also determined that furin-mediated pro-OCN cleavage occurred independently of its γ-carboxylation, a posttranslational modification that is known to hamper OCN endocrine action. However, because pro-OCN is not efficiently decarboxylated and activated during bone resorption, inactivation of furin in osteoblasts in mice resulted in decreased circulating levels of undercarboxylated OCN, impaired glucose tolerance, and reduced energy expenditure. Furthermore, we show that Furin deletion in osteoblasts reduced appetite, a function not modulated by OCN, thus suggesting that osteoblasts may secrete additional hormones that regulate different aspects of energy metabolism. Accordingly, the metabolic defects of the mice lacking furin in osteoblasts became more apparent under pair-feeding conditions. These findings identify furin as an important regulator of bone endocrine function.
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Affiliation(s)
- Omar Al Rifai
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Molecular Biology Programs of the Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Jacqueline Chow
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Julie Lacombe
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Catherine Julien
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | | | | | - Rachid Essalmani
- Biochemical Neuroendocrinology Research Unit, IRCM, Québec, Canada
| | | | - Nabil G Seidah
- Biochemical Neuroendocrinology Research Unit, IRCM, Québec, Canada.,Department of Medicine, Université de Montréal, Québec, Canada.,Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
| | - Mathieu Ferron
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Molecular Biology Programs of the Faculty of Medicine, Université de Montréal, Québec, Canada.,Department of Medicine, Université de Montréal, Québec, Canada.,Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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22
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Levinger I, Brennan-Speranza TC, Zulli A, Parker L, Lin X, Lewis JR, Yeap BB. Multifaceted interaction of bone, muscle, lifestyle interventions and metabolic and cardiovascular disease: role of osteocalcin. Osteoporos Int 2017; 28:2265-2273. [PMID: 28289780 DOI: 10.1007/s00198-017-3994-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/28/2017] [Indexed: 12/22/2022]
Abstract
Undercarboxylated osteocalcin (ucOC) may play a role in glucose homeostasis and cardiometabolic health. This review examines the epidemiological and interventional evidence associating osteocalcin (OC) and ucOC with metabolic risk and cardiovascular disease. The complexity in assessing such correlations, due to the observational nature of human studies, is discussed. Several studies have reported that higher levels of ucOC and OC are correlated with lower fat mass and HbA1c. In addition, improved measures of glycaemic control via pharmacological and non-pharmacological (e.g. exercise or diet) interventions are often associated with increased circulating levels of OC and/or ucOC. There is also a relationship between lower circulating OC and ucOC and increased measures of vascular calcification and cardiovascular disease. However, not all studies have reported such relationship, some with contradictory findings. Equivocal findings may arise because of the observational nature of the studies and the inability to directly assess the relationship between OC and ucOC on glycaemic control and cardiovascular health in humans. Studying OC and ucOC in humans is further complicated due to numerous confounding factors such as sex differences, menopausal status, vitamin K status, physical activity level, body mass index, insulin sensitivity (normal/insulin resistance/T2DM), tissue-specific effects and renal function among others. Current observational and indirect interventional evidence appears to support a relationship between ucOC with metabolic and cardiovascular disease. There is also emerging evidence to suggest a direct role of ucOC in human metabolism. Further mechanistic studies are required to (a) clarify causality, (b) explore mechanisms involved and
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Affiliation(s)
- I Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
| | - T C Brennan-Speranza
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - A Zulli
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia
| | - L Parker
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia
| | - X Lin
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia
| | - J R Lewis
- Centre for Kidney Research, Children's Hospital at Westmead School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - B B Yeap
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
- Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Perth, Australia
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23
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De Toni L, Di Nisio A, Rocca MS, De Rocco Ponce M, Ferlin A, Foresta C. Osteocalcin, a bone-derived hormone with important andrological implications. Andrology 2017; 5:664-670. [PMID: 28395130 DOI: 10.1111/andr.12359] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/08/2017] [Accepted: 02/19/2017] [Indexed: 01/01/2023]
Abstract
Increasing evidence disclosed the existence of a novel multi-organ endocrine pathway, involving bone, pancreas and testis, of high penetrance in energy metabolism and male fertility. The main mediator of this axis is undercarboxylated osteocalcin (ucOC), a bone-derived protein-exerting systemic effects on tissues expressing the metabotropic receptor GPRC6A. The recognized effects of ucOC are the improvement of insulin secretion from the pancreas, the amelioration of systemic insulin sensitivity, in particular in skeletal muscle, and the stimulation of the global endocrine activity of the Leydig cell, including vitamin D 25-hydroxylation and testosterone production. The supporting evidence of this circuit in both animal and human models is here reviewed, with particular emphasis on the role of ucOC on testis function. The possible pharmacological modulation of this hormonal circuit for therapeutic aims is also discussed.
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Affiliation(s)
- L De Toni
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - A Di Nisio
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - M S Rocca
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - M De Rocco Ponce
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - A Ferlin
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - C Foresta
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
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24
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Pi M, Nishimoto SK, Quarles LD. GPRC6A: Jack of all metabolism (or master of none). Mol Metab 2016; 6:185-193. [PMID: 28180060 PMCID: PMC5279936 DOI: 10.1016/j.molmet.2016.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/05/2016] [Accepted: 12/15/2016] [Indexed: 01/06/2023] Open
Abstract
Background GPRC6A, a widely expressed G-protein coupled receptor, is proposed to be a master regulator of complex endocrine networks and metabolic processes. GPRC6A is activated by multiple ligands, including osteocalcin (Ocn), testosterone (T), basic amino acids, and various cations. Scope of Review We review the controversy surrounding GPRC6A functions. In mice, GPRC6A is proposed to integrate metabolic functions through the coordinated secretion of hormones, including insulin, GLP-1, T, and IL-6, and direct effects of this receptor to control glucose and fat metabolism in the liver, skeletal muscle, and fat. Loss-of-GPRC6A results in metabolic syndrome (MetS), and activation of GPRC6A stimulates proliferation of β-cells, increases peripheral insulin sensitivity, and protects against high fat diet (HFD) induced metabolic abnormalities in most mouse models. Bone, cardiovascular, immune, and skin functions of GPRC6A have also been identified in mice. Expression of GPRC6A is increased in prostate cancer (PCa) cells, and inhibition of GPRC6A attenuates PCa progression in mouse models. The function of GPRC6A in humans, however, is not clear. During evolution, a unique polymorphism of GPRC6A emerged mainly in humans of Asian and European decent that has been proposed to alter membrane trafficking and function. In contrast, the ancestral allele found in all other species is retained in 1%, 15%, and 40% of people of Asian, European and African descent, respectively, suggesting GPRC6A gene variants may contribute to the racial disparities in the risk of developing MetS and PCa. Major Conclusions If the regulatory functions of GPRC6A identified in mice translate to humans, and polymorphisms in GPRC6A are found to predict racial disparities in human diseases, GPRC6A may be a new gene target to predict, prevent, and treat MetS, PCa, and other disorders impacted by GPRC6A.
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Affiliation(s)
- Min Pi
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Satoru Kenneth Nishimoto
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - L Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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