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Yang W, Zuo Y, Zhang N, Wang K, Zhang R, Chen Z, He Q. GNAS locus: bone related diseases and mouse models. Front Endocrinol (Lausanne) 2023; 14:1255864. [PMID: 37920253 PMCID: PMC10619756 DOI: 10.3389/fendo.2023.1255864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/29/2023] [Indexed: 11/04/2023] Open
Abstract
GNASis a complex locus characterized by multiple transcripts and an imprinting effect. It orchestrates a variety of physiological processes via numerous signaling pathways. Human diseases associated with the GNAS gene encompass fibrous dysplasia (FD), Albright's Hereditary Osteodystrophy (AHO), parathyroid hormone(PTH) resistance, and Progressive Osseous Heteroplasia (POH), among others. To facilitate the study of the GNAS locus and its associated diseases, researchers have developed a range of mouse models. In this review, we will systematically explore the GNAS locus, its related signaling pathways, the bone diseases associated with it, and the mouse models pertinent to these bone diseases.
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Affiliation(s)
- Wan Yang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yiyi Zuo
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Nuo Zhang
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Kangning Wang
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Runze Zhang
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Ziyi Chen
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Qing He
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
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Wyss P, Song C, Bina M. Along the Bos taurus genome, uncover candidate imprinting control regions. BMC Genomics 2022; 23:478. [PMID: 35764919 PMCID: PMC9241299 DOI: 10.1186/s12864-022-08694-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/01/2022] [Indexed: 11/17/2022] Open
Abstract
Background In mammals, Imprinting Control Regions (ICRs) regulate a subset of genes in a parent-of-origin-specific manner. In both human and mouse, previous studies identified a set of CpG-rich motifs occurring as clusters in ICRs and germline Differentially Methylated Regions (gDMRs). These motifs consist of the ZFP57 binding site (ZFBS) overlapping a subset of MLL binding units known as MLL morphemes. MLL or MLL1 (Mixed Lineage Leukemia 1) is a relatively large multidomain protein that plays a central role in the regulation of transcription. The structures of both MLL1 and MLL2 include a domain (MT) that binds CpG-rich DNA and a conserved domain (SET) that methylates lysine 4 in histone H3 producing H3K4me3 marks in chromatin. Results Since genomic imprinting impacts many developmental and key physiological processes, we followed a previous bioinformatics strategy to pinpoint ICR positions in the Bos taurus genome. Initial genome-wide analyses involved finding the positions of ZFP57 binding sites, and the CpG-rich motifs (ZFBS-morph overlaps) along cattle chromosomal DNA. By creating plots displaying the density of ZFBS-morph overlaps, we removed background noise and thus improved signal detection. With the density-plots, we could view the positions of peaks locating known and candidate ICRs in cattle DNA. Our evaluations revealed the correspondence of peaks in plots to reported known and inferred ICRs/DMRs in cattle. Beside peaks pinpointing such ICRs, the density-plots also revealed additional peaks. Since evaluations validated the robustness of our approach, we inferred that the additional peaks may correspond to candidate ICRs for imprinted gene expression. Conclusion Our bioinformatics strategy offers the first genome-wide approach for systematically localizing candidate ICRs. Furthermore, we have tailored our datasets for upload onto the UCSC genome browser so that researchers could find known and candidate ICRs with respect to a wide variety of annotations at all scales: from the positions of Single Nucleotide Polymorphisms (SNPs), to positions of genes, transcripts, and repeated DNA elements. Furthermore, the UCSC genome browser offers tools to produce enlarged views: to uncover the genes in the vicinity of candidate ICRs and thus discover potential imprinted genes for experimental validations. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08694-3.
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Affiliation(s)
- Phillip Wyss
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Carol Song
- Information Technology, Purdue University, West Lafayette, IN, 47907, USA
| | - Minou Bina
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
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A Naturally Occurring Membrane-Anchored Gα s Variant, XLαs, Activates Phospholipase Cβ4. J Biol Chem 2022; 298:102134. [PMID: 35709985 PMCID: PMC9294334 DOI: 10.1016/j.jbc.2022.102134] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 12/02/2022] Open
Abstract
Extra-large stimulatory Gα (XLαs) is a large variant of G protein αs subunit (Gαs) that uses an alternative promoter and thus differs from Gαs at the first exon. XLαs activation by G protein–coupled receptors mediates cAMP generation, similarly to Gαs; however, Gαs and XLαs have been shown to have distinct cellular and physiological functions. For example, previous work suggests that XLαs can stimulate inositol phosphate production in renal proximal tubules and thereby regulate serum phosphate levels. In this study, we show that XLαs directly and specifically stimulates a specific isoform of phospholipase Cβ (PLCβ), PLCβ4, both in transfected cells and with purified protein components. We demonstrate that neither the ability of XLαs to activate cAMP generation nor the canonical G protein switch II regions are required for PLCβ stimulation. Furthermore, this activation is nucleotide independent but is inhibited by Gβγ, suggesting a mechanism of activation that relies on Gβγ subunit dissociation. Surprisingly, our results indicate that enhanced membrane targeting of XLαs relative to Gαs confers the ability to activate PLCβ4. We also show that PLCβ4 is required for isoproterenol-induced inositol phosphate accumulation in osteocyte-like Ocy454 cells. Taken together, we demonstrate a novel mechanism for activation of phosphoinositide turnover downstream of Gs-coupled receptors that may have a critical role in endocrine physiology.
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Liu Y, Yang Y, Chu L, Ren S, Li Y, Gao A, Wen J, Deng W, Lu Y, Kong L, Liang B, Shao X. Case Report: A Paternal 20q13.2-q13.32 Deletion Patient With Growth Retardation Improved by Growth Hormone. Front Genet 2022; 13:859185. [PMID: 35401665 PMCID: PMC8987769 DOI: 10.3389/fgene.2022.859185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
Interstitial chromosome 20q deletions, containing GNAS imprinted locus, are rarely reported in the past. Hereby, we presented a Chinese boy with a novel 4.36 Mb deletion at paternal 20q13.2-13.32, showing feeding difficulty, malnutrition, short stature, lower limb asymmetry, sightly abnormal facial appearance and mild intellectual abnormality. With 3 years’ growth hormone treatment, his height was increased from 90 to 113.5 cm. This report is the first time to describe the outcome of clinical treatment on a patient with this rare chromosomal 20 long arm interstitial deletion, containing GNAS locus, which may facilitate the diagnosis and treatment of this type of patient in the future.
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Affiliation(s)
- Yu Liu
- Department of Pediatric Endocrinology, Genetics and Metabolism, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
| | - Ying Yang
- Department of Pediatric Endocrinology, Genetics and Metabolism, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
| | - Liming Chu
- Basecare Medical Device Co., Ltd., Suzhou, China
| | - Shuai Ren
- Basecare Medical Device Co., Ltd., Suzhou, China
| | - Ying Li
- Basecare Medical Device Co., Ltd., Suzhou, China
| | - Aimin Gao
- Department of Pediatric Endocrinology, Genetics and Metabolism, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
| | - Jing Wen
- Department of Pediatric Endocrinology, Genetics and Metabolism, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
| | - Wanling Deng
- Department of Pediatric Endocrinology, Genetics and Metabolism, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
| | - Yan Lu
- Department of Pediatric Endocrinology, Genetics and Metabolism, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
| | - Lingyin Kong
- Basecare Medical Device Co., Ltd., Suzhou, China
| | - Bo Liang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Bo Liang, ; Xiaoshan Shao,
| | - Xiaoshan Shao
- Department of Renal Rheumatology and Immunology, Guiyang Maternal and Child Health Care Hospital, Guiyang Children’s Hospital, Guiyang, China
- *Correspondence: Bo Liang, ; Xiaoshan Shao,
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Cui Q, Aksu C, Ay B, Remillard CE, Plagge A, Gardezi M, Dunlap M, Gerstenfeld LC, He Q, Bastepe M. Maternal GNAS Contributes to the Extra-Large G Protein α-Subunit (XLαs) Expression in a Cell Type-Specific Manner. Front Genet 2021; 12:680537. [PMID: 34220953 PMCID: PMC8247768 DOI: 10.3389/fgene.2021.680537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 05/12/2021] [Indexed: 11/25/2022] Open
Abstract
GNAS encodes the stimulatory G protein alpha-subunit (Gsα) and its large variant XLαs. Studies have suggested that XLαs is expressed exclusively paternally. Thus, XLαs deficiency is considered to be responsible for certain findings in patients with paternal GNAS mutations, such as pseudo-pseudohypoparathyroidism, and the phenotypes associated with maternal uniparental disomy of chromosome 20, which comprises GNAS. However, a study of bone marrow stromal cells (BMSC) suggested that XLαs could be biallelically expressed. Aberrant BMSC differentiation due to constitutively activating GNAS mutations affecting both Gsα and XLαs is the underlying pathology in fibrous dysplasia of bone. To investigate allelic XLαs expression, we employed next-generation sequencing and a polymorphism common to XLαs and Gsα, as well as A/B, another paternally expressed GNAS transcript. In mouse BMSCs, Gsα transcripts were 48.4 ± 0.3% paternal, while A/B was 99.8 ± 0.2% paternal. In contrast, XLαs expression varied among different samples, paternal contribution ranging from 43.0 to 99.9%. Sample-to-sample variation in paternal XLαs expression was also detected in bone (83.7-99.6%) and cerebellum (83.8 to 100%) but not in cultured calvarial osteoblasts (99.1 ± 0.1%). Osteoblastic differentiation of BMSCs shifted the paternal XLαs expression from 83.9 ± 1.5% at baseline to 97.2 ± 1.1%. In two human BMSC samples grown under osteoinductive conditions, XLαs expression was also predominantly monoallelic (91.3 or 99.6%). Thus, the maternal GNAS contributes significantly to XLαs expression in BMSCs but not osteoblasts. Altered XLαs activity may thus occur in certain cell types irrespective of the parental origin of a GNAS defect.
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Affiliation(s)
- Qiuxia Cui
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Cagri Aksu
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Birol Ay
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Claire E. Remillard
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Antonius Plagge
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Mina Gardezi
- Department of Orthopaedic Surgery, Boston University School of Medicine, Boston, MA, United States
| | - Margaret Dunlap
- Department of Orthopaedic Surgery, Boston University School of Medicine, Boston, MA, United States
| | - Louis C. Gerstenfeld
- Department of Orthopaedic Surgery, Boston University School of Medicine, Boston, MA, United States
| | - Qing He
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- School of Stomatology, Wuhan University, Wuhan, China
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
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Wang Y, Tian H, Chen X. The Distinct Role of the Extra-Large G Protein ɑ-Subunit XLɑs. Calcif Tissue Int 2020; 107:212-219. [PMID: 32596800 DOI: 10.1007/s00223-020-00714-2] [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: 03/22/2020] [Accepted: 06/17/2020] [Indexed: 02/05/2023]
Abstract
GNAS is one of the most complex gene loci in the human genome and encodes multiple gene products including Gsα, XLαs, NESP55, A/B, and AS transcripts. XLαs, the extra-large G protein ɑ-subunit, is paternally expressed. XLɑs and Gsɑ share the common 2-13 exons with different promoters and first exons. Therefore, XLɑs contains most of the functional domains of Gsα including receptor and effector binding sites. In vitro studies suggest a "Gsɑ"-like function of XLɑs regarding the stimulation of cAMP generation in response to receptor activation with different cellular actions. However, it is unclear whether XLαs has an important physiological function in humans. Pseudopseudohypoparathyroidism (PPHP) and progressive osseous heteroplasia (POH) are caused by paternally inherited mutations of GNAS. Maternal uniparental disomy of chromosome 20 [UPD(20)mat] lacks paternal chromosome 20. Therefore, the phenotypes of these diseases may be secondary to the abnormal functions of XLɑs, at least partly. From the phenotypes of human diseases like PPHP, POH, and UPD(20)mat, as well as some animal models with deficient XLɑs functions, it could be seen that XLɑs is involved in the growth and development of the mammalian fetus, plays a different role in glucose, lipid, and energy metabolism when compared with Gsɑ, and could prevent heterotopic ossification in humans and mice. More in vivo and in vitro studies, especially the development of conditional XLɑs knockout mice, are needed to clarify the physiopathologic roles and related signal pathways of XLɑs.
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Affiliation(s)
- Yan Wang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, West China Hospital, Sichuan University, No. 37 Guoxue Xiang, Chengdu, 610041, China
| | - Haoming Tian
- Department of Endocrinology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiang Chen
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, West China Hospital, Sichuan University, No. 37 Guoxue Xiang, Chengdu, 610041, China.
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8
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Chen X, Meng Y, Tang M, Wang Y, Xie Y, Wan S, Tian H, Yu X. A paternally inherited non-sense variant c.424G>T (p.G142*) in the first exon of XLαs in an adult patient with hypophosphatemia and osteopetrosis. Clin Genet 2020; 97:712-722. [PMID: 32157680 DOI: 10.1111/cge.13734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/05/2023]
Abstract
XLαs, the extra-large isoform of alpha-subunit of the stimulatory guanine nucleotide-binding protein (Gsα), is paternally expressed. The significance of XLαs in humans remains largely unknown. Here, we report a patient who presented with increased bone mass, hypophosphatemia, and elevated parathyroid hormone (PTH) levels. His serum calcium was in the lower limit of the normal range. Whole exome sequencing of this subject found a novel non-sense variant c.424G>T (p. G142*) in the first exon of XLαs, which was inherited from his father and transmitted to his daughter. This variant was predicted to exclusively influence the expression of XLαs, while possibly having no significant effects on other gene products of this locus. Ellsworth-Howard test revealed normal renal response to PTH in proband. Human SaOS2 cells transfected with mutant XLαs failed to generate cyclic adenosine monophosphate under PTH stimulation, indicating skeletal resistance to this hormone. This subject showed higher circulating sclerostin, dickkopf1, and osteoprotegerin (OPG) levels, while lower receptor activator of nuclear factor kappa-B ligand/OPG ratio, leading to reduced bone resorption. Our findings indicate that XLαs plays a critical role in bone metabolism and GNAS locus should be considered as a candidate gene for high bone mass.
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Affiliation(s)
- Xiang Chen
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Meng
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Mengjia Tang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Wang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ying Xie
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Shan Wan
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Haoming Tian
- Department of Endocrinology, West China Hospital, Sichuan University, Chengdu, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
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Matthias J, Cui Q, Shumate LT, Plagge A, He Q, Bastepe M. Extra-Large Gα Protein (XLαs) Deficiency Causes Severe Adenine-Induced Renal Injury with Massive FGF23 Elevation. Endocrinology 2020; 161:5638044. [PMID: 31758181 PMCID: PMC6986553 DOI: 10.1210/endocr/bqz025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/22/2019] [Indexed: 11/19/2022]
Abstract
Fibroblast growth factor-23 (FGF23) is critical for phosphate and vitamin D homeostasis. Cellular and molecular mechanisms underlying FGF23 production remain poorly defined. The extra-large Gα subunit (XLαs) is a variant of the stimulatory G protein alpha-subunit (Gsα), which mediates the stimulatory action of parathyroid hormone in skeletal FGF23 production. XLαs ablation causes diminished FGF23 levels in early postnatal mice. Herein we found that plasma FGF23 levels were comparable in adult XLαs knockout (XLKO) and wild-type littermates. Upon adenine-rich diet-induced renal injury, a model of chronic kidney disease, both mice showed increased levels of plasma FGF23. Unexpectedly, XLKO mice had markedly higher FGF23 levels than WT mice, with higher blood urea nitrogen and more severe tubulopathy. FGF23 mRNA levels increased substantially in bone and bone marrow in both genotypes; however, the levels in bone were markedly higher than in bone marrow. In XLKO mice, a positive linear correlation was observed between plasma FGF23 and bone, but not bone marrow, FGF23 mRNA levels, suggesting that bone, rather than bone marrow, is an important contributor to severely elevated FGF23 levels in this model. Upon folic acid injection, a model of acute kidney injury, XLKO and WT mice exhibited similar degrees of tubulopathy; however, plasma phosphate and FGF23 elevations were modestly blunted in XLKO males, but not in females, compared to WT counterparts. Our findings suggest that XLαs ablation does not substantially alter FGF23 production in adult mice but increases susceptibility to adenine-induced kidney injury, causing severe FGF23 elevations in plasma and bone.
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Affiliation(s)
- Julia Matthias
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Qiuxia Cui
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Lauren T Shumate
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Antonius Plagge
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Qing He
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- Correspondence: Murat Bastepe, MD, PhD, 50 Blossom St. Thier 10 Boston, MA 02114, USA. E-mail: and Qing He, PhD 50 Blossom St. Thier 10 Boston, Massachusetts 02114, USA. E-mail:
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- Correspondence: Murat Bastepe, MD, PhD, 50 Blossom St. Thier 10 Boston, MA 02114, USA. E-mail: and Qing He, PhD 50 Blossom St. Thier 10 Boston, Massachusetts 02114, USA. E-mail:
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He Q, Shumate LT, Matthias J, Aydin C, Wein MN, Spatz JM, Goetz R, Mohammadi M, Plagge A, Divieti Pajevic P, Bastepe M. A G protein-coupled, IP3/protein kinase C pathway controlling the synthesis of phosphaturic hormone FGF23. JCI Insight 2019; 4:125007. [PMID: 31484825 PMCID: PMC6777913 DOI: 10.1172/jci.insight.125007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 08/01/2019] [Indexed: 12/23/2022] Open
Abstract
Dysregulated actions of bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23) result in several inherited diseases, such as X-linked hypophosphatemia (XLH), and contribute substantially to the mortality in kidney failure. Mechanisms governing FGF23 production are poorly defined. We herein found that ablation of the Gq/11α-like, extralarge Gα subunit (XLαs), a product of GNAS, exhibits FGF23 deficiency and hyperphosphatemia in early postnatal mice (XLKO). FGF23 elevation in response to parathyroid hormone, a stimulator of FGF23 production via cAMP, was intact in XLKO mice, while skeletal levels of protein kinase C isoforms α and δ (PKCα and PKCδ) were diminished. XLαs ablation in osteocyte-like Ocy454 cells suppressed the levels of FGF23 mRNA, inositol 1,4,5-trisphosphate (IP3), and PKCα/PKCδ proteins. PKC activation in vivo via injecting phorbol myristate acetate (PMA) or by constitutively active Gqα-Q209L in osteocytes and osteoblasts promoted FGF23 production. Molecular studies showed that the PKC activation-induced FGF23 elevation was dependent on MAPK signaling. The baseline PKC activity was elevated in bones of Hyp mice, a model of XLH. XLαs ablation significantly, but modestly, reduced serum FGF23 and elevated serum phosphate in Hyp mice. These findings reveal a potentially hitherto-unknown mechanism of FGF23 synthesis involving a G protein-coupled IP3/PKC pathway, which may be targeted to fine-tune FGF23 levels.
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Affiliation(s)
- Qing He
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Lauren T. Shumate
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Julia Matthias
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Cumhur Aydin
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Department of Endodontics, Gulhane Faculty of Dentistry, University of Health Sciences, Ankara, Turkey
| | - Marc N. Wein
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jordan M. Spatz
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Regina Goetz
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Moosa Mohammadi
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Antonius Plagge
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Paola Divieti Pajevic
- Department of Molecular & Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, USA
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Garcia C, Maurel-Ribes A, Nauze M, N'Guyen D, Martinez LO, Payrastre B, Sénard JM, Galés C, Pons V. Deciphering biased inverse agonism of cangrelor and ticagrelor at P2Y 12 receptor. Cell Mol Life Sci 2019; 76:561-576. [PMID: 30406277 PMCID: PMC11105710 DOI: 10.1007/s00018-018-2960-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 10/15/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
P2Y12 receptor (P2Y12-R) is one of the major targets for drug inhibiting platelet aggregation in the treatment/prevention of arterial thrombosis. However, the clinical use of P2Y12-R antagonists faces some limitations, such as a delayed onset of action (clopidogrel) or adverse effect profile (ticagrelor, cangrelor), justifying the development of a new generation of P2Y12-R antagonists with a better clinical benefit-risk balance. Although the recent concept of biased agonism offers the possibility to alleviate undesirable adverse effects while preserving therapeutic outcomes, it has never been explored at P2Y12-R. For the first time, using highly sensitive BRET2-based probes, we accurately delineated biased ligand efficacy at P2Y12-R in living HEK293T cells on G protein activation and downstream effectors. We demonstrated that P2Y12-R displayed constitutive Gi/o-dependent signaling that is impaired by the R122C mutation, previously associated with a bleeding disorder. More importantly, we reported the biased inverse agonist efficacy of cangrelor and ticagrelor that could underlie their clinical efficacy. Our study points out that constitutive P2Y12-R signaling is a normal feature of the receptor that might be essential for platelets to respond faster to a vessel injury. From a therapeutic standpoint, our data suggest that the beneficial advantages of antiplatelet drugs might be more related to inverse agonism at P2Y12-R than to antagonism of ADP-mediated signaling. In the future, deciphering P2Y12-R constitutive activity should allow the discovery of more selective biased P2Y12-R blockers demonstrating therapeutic advantages over classical antiplatelet drugs by improving therapeutic outcomes and concomitantly relieving undesirable adverse effects.
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Affiliation(s)
- Cédric Garcia
- Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, 31000, Toulouse, France
| | - Agnès Maurel-Ribes
- Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, 31000, Toulouse, France
| | - Michel Nauze
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Du N'Guyen
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Laurent O Martinez
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Bernard Payrastre
- Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, 31000, Toulouse, France
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Jean-Michel Sénard
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
- Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, 31000, Toulouse, France
| | - Céline Galés
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Véronique Pons
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France.
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Abstract
GNAS is a complex imprinted gene encoding the alpha-subunit of the stimulatory heterotrimeric G protein (Gsα). GNAS gives rise to additional gene products that exhibit exclusively maternal or paternal expression, such as XLαs, a large variant of Gsα that shows exclusively paternal expression and is partly identical to the latter. Gsα itself is expressed biallelically in most tissues, although the expression occurs predominantly from the maternal allele in a small set of tissues, such as renal proximal tubules. Inactivating mutations in Gsα-coding GNAS exons are responsible for Albright's hereditary osteodystrophy (AHO), which refers to a constellation of physical and developmental disorders including obesity, short stature, brachydactyly, cognitive impairment, and heterotopic ossification. Patients with Gsα mutations can present with AHO in the presence or absence of end-organ resistance to multiple hormones including parathyroid hormone. Maternal Gsα mutations lead to AHO with hormone resistance (i.e. pseudohypoparathyroidism type-Ia), whereas paternal mutations cause AHO alone (i.e. pseudo-pseudohypoparathyroidism). Heterotopic ossification associated with AHO develops through intramembranous bone formation and is limited to dermis and subcutis. In rare cases carrying Gsα mutations, however, ossifications progress into deep connective tissue and skeletal muscle, a disorder termed progressive osseous heteroplasia (POH). Here I briefly review the genetic, clinical, and molecular aspects of these disorders caused by inactivating GNAS mutations, with particular emphasis on heterotopic ossification.
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Affiliation(s)
- Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, United States.
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Cyclic AMP Recruits a Discrete Intracellular Ca 2+ Store by Unmasking Hypersensitive IP 3 Receptors. Cell Rep 2017; 18:711-722. [PMID: 28099849 PMCID: PMC5276804 DOI: 10.1016/j.celrep.2016.12.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/17/2016] [Accepted: 12/19/2016] [Indexed: 12/12/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3) stimulates Ca2+ release from the endoplasmic reticulum (ER), and the response is potentiated by 3′,5′-cyclic AMP (cAMP). We investigated this interaction in HEK293 cells using carbachol and parathyroid hormone (PTH) to stimulate formation of IP3 and cAMP, respectively. PTH alone had no effect on the cytosolic Ca2+ concentration, but it potentiated the Ca2+ signals evoked by carbachol. Surprisingly, however, the intracellular Ca2+ stores that respond to carbachol alone could be both emptied and refilled without affecting the subsequent response to PTH. We provide evidence that PTH unmasks high-affinity IP3 receptors within a discrete Ca2+ store. We conclude that Ca2+ stores within the ER that dynamically exchange Ca2+ with the cytosol maintain a functional independence that allows one store to be released by carbachol and another to be released by carbachol with PTH. Compartmentalization of ER Ca2+ stores adds versatility to IP3-evoked Ca2+ signals. Cyclic AMP directly potentiates IP3-evoked Ca2+ release The Ca2+ stores released by IP3 alone or IP3 with cAMP are functionally independent Cyclic AMP unmasks high-affinity IP3 receptors in a discrete ER Ca2+ store Independent regulation of discrete Ca2+ stores increases signaling versatility
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Large G protein α-subunit XLαs limits clathrin-mediated endocytosis and regulates tissue iron levels in vivo. Proc Natl Acad Sci U S A 2017; 114:E9559-E9568. [PMID: 29078380 DOI: 10.1073/pnas.1712670114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alterations in the activity/levels of the extralarge G protein α-subunit (XLαs) are implicated in various human disorders, such as perinatal growth retardation. Encoded by GNAS, XLαs is partly identical to the α-subunit of the stimulatory G protein (Gsα), but the cellular actions of XLαs remain poorly defined. Following an initial proteomic screen, we identified sorting nexin-9 (SNX9) and dynamins, key components of clathrin-mediated endocytosis, as binding partners of XLαs. Overexpression of XLαs in HEK293 cells inhibited internalization of transferrin, a process that depends on clathrin-mediated endocytosis, while its ablation by CRISPR/Cas9 in an osteocyte-like cell line (Ocy454) enhanced it. Similarly, primary cardiomyocytes derived from XLαs knockout (XLKO) pups showed enhanced transferrin internalization. Early postnatal XLKO mice showed a significantly higher degree of cardiac iron uptake than wild-type littermates following iron dextran injection. In XLKO neonates, iron and ferritin levels were elevated in heart and skeletal muscle, where XLαs is normally expressed abundantly. XLKO heart and skeletal muscle, as well as XLKO Ocy454 cells, showed elevated SNX9 protein levels, and siRNA-mediated knockdown of SNX9 in XLKO Ocy454 cells prevented enhanced transferrin internalization. In transfected cells, XLαs also inhibited internalization of the parathyroid hormone and type 2 vasopressin receptors. Internalization of transferrin and these G protein-coupled receptors was also inhibited in cells expressing an XLαs mutant missing the Gα portion, but not Gsα or an N-terminally truncated XLαs mutant unable to interact with SNX9 or dynamin. Thus, XLαs restricts clathrin-mediated endocytosis and plays a critical role in iron/transferrin uptake in vivo.
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Bastepe M, Turan S, He Q. Heterotrimeric G proteins in the control of parathyroid hormone actions. J Mol Endocrinol 2017; 58:R203-R224. [PMID: 28363951 PMCID: PMC5650080 DOI: 10.1530/jme-16-0221] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 02/17/2017] [Indexed: 12/17/2022]
Abstract
Parathyroid hormone (PTH) is a key regulator of skeletal physiology and calcium and phosphate homeostasis. It acts on bone and kidney to stimulate bone turnover, increase the circulating levels of 1,25 dihydroxyvitamin D and calcium and inhibit the reabsorption of phosphate from the glomerular filtrate. Dysregulated PTH actions contribute to or are the cause of several endocrine disorders. This calciotropic hormone exerts its actions via binding to the PTH/PTH-related peptide receptor (PTH1R), which couples to multiple heterotrimeric G proteins, including Gs and Gq/11 Genetic mutations affecting the activity or expression of the alpha-subunit of Gs, encoded by the GNAS complex locus, are responsible for several human diseases for which the clinical findings result, at least partly, from aberrant PTH signaling. Here, we review the bone and renal actions of PTH with respect to the different signaling pathways downstream of these G proteins, as well as the disorders caused by GNAS mutations.
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Affiliation(s)
- Murat Bastepe
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Serap Turan
- Department of Pediatric EndocrinologyMarmara University School of Medicine, Istanbul, Turkey
| | - Qing He
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Galandrin S, Onfroy L, Poirot MC, Sénard JM, Galés C. Delineating biased ligand efficacy at 7TM receptors from an experimental perspective. Int J Biochem Cell Biol 2016; 77:251-63. [PMID: 27107932 DOI: 10.1016/j.biocel.2016.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/15/2016] [Accepted: 04/16/2016] [Indexed: 12/17/2022]
Abstract
During the last 10 years, the concept of "biased agonism" also called "functional selectivity" swamped the pharmacology of 7 transmembrane receptors and paved the way for developing signaling pathway-selective drugs with increased efficacy and less adverse effects. Initially thought to select the activation of only a subset of the signaling pathways by the reference agonist, bias ligands revealed higher complexity as they have been shown to stabilize variable receptor conformations that associate with distinct signaling events from the reference. Today, one major challenge relies on the in vitro determination of the bias and classification of these ligands, as a prerequisite for future in vivo and clinical translation. In this review, current experimental considerations for the bias evaluation related to choice of the cellular model, of the signaling pathway as well as of the assays are presented and discussed.
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Affiliation(s)
- Ségolène Galandrin
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France
| | - Lauriane Onfroy
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France
| | - Mathias Charles Poirot
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France
| | - Jean-Michel Sénard
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France; Service de Pharmacologie Clinique, Faculté de médecine, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, F-31000 Toulouse, France
| | - Céline Galés
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France.
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Reductions in hypothalamic Gfap expression, glial cells and α-tanycytes in lean and hypermetabolic Gnasxl-deficient mice. Mol Brain 2016; 9:39. [PMID: 27080240 PMCID: PMC4832494 DOI: 10.1186/s13041-016-0219-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/08/2016] [Indexed: 01/31/2023] Open
Abstract
Background Neuronal and glial differentiation in the murine hypothalamus is not complete at birth, but continues over the first two weeks postnatally. Nutritional status and Leptin deficiency can influence the maturation of neuronal projections and glial patterns, and hypothalamic gliosis occurs in mouse models of obesity. Gnasxl constitutes an alternative transcript of the genomically imprinted Gnas locus and encodes a variant of the signalling protein Gαs, termed XLαs, which is expressed in defined areas of the hypothalamus. Gnasxl-deficient mice show postnatal growth retardation and undernutrition, while surviving adults remain lean and hypermetabolic with increased sympathetic nervous system (SNS) activity. Effects of this knock-out on the hypothalamic neural network have not yet been investigated. Results RNAseq analysis for gene expression changes in hypothalami of Gnasxl-deficient mice indicated Glial fibrillary acid protein (Gfap) expression to be significantly down-regulated in adult samples. Histological analysis confirmed a reduction in Gfap-positive glial cell numbers specifically in the hypothalamus. This reduction was observed in adult tissue samples, whereas no difference was found in hypothalami of postnatal stages, indicating an adaptation in adult Gnasxl-deficient mice to their earlier growth phenotype and hypermetabolism. Especially noticeable was a loss of many Gfap-positive α-tanycytes and their processes, which form part of the ependymal layer that lines the medial and dorsal regions of the 3rd ventricle, while β-tanycytes along the median eminence (ME) and infundibular recesses appeared unaffected. This was accompanied by local reductions in Vimentin and Nestin expression. Hypothalamic RNA levels of glial solute transporters were unchanged, indicating a potential compensatory up-regulation in the remaining astrocytes and tanycytes. Conclusion Gnasxl deficiency does not directly affect glial development in the hypothalamus, since it is expressed in neurons, and Gfap-positive astrocytes and tanycytes appear normal during early postnatal stages. The loss of Gfap-expressing cells in adult hypothalami appears to be a consequence of the postnatal undernutrition, hypoglycaemia and continued hypermetabolism and leanness of Gnasxl-deficient mice, which contrasts with gliosis observed in obese mouse models. Since α-tanycytes also function as adult neural progenitor cells, these findings might indicate further developmental abnormalities in hypothalamic formations of Gnasxl-deficient mice, potentially including neuronal composition and projections. Electronic supplementary material The online version of this article (doi:10.1186/s13041-016-0219-1) contains supplementary material, which is available to authorized users.
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Using AAV vectors expressing the β2-adrenoceptor or associated Gα proteins to modulate skeletal muscle mass and muscle fibre size. Sci Rep 2016; 6:23042. [PMID: 26972746 PMCID: PMC4789796 DOI: 10.1038/srep23042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/25/2016] [Indexed: 01/06/2023] Open
Abstract
Anabolic β2-adrenoceptor (β2-AR) agonists have been proposed as therapeutics for treating muscle wasting but concerns regarding possible off-target effects have hampered their use. We investigated whether β2-AR-mediated signalling could be modulated in skeletal muscle via gene delivery to the target tissue, thereby avoiding the risks of β2-AR agonists. In mice, intramuscular administration of a recombinant adeno-associated virus-based vector (rAAV vector) expressing the β2-AR increased muscle mass by >20% within 4 weeks. This hypertrophic response was comparable to that of 4 weeks’ treatment with the β2-AR agonist formoterol, and was not ablated by mTOR inhibition. Increasing expression of inhibitory (Gαi2) and stimulatory (GαsL) G-protein subunits produced minor atrophic and hypertrophic changes in muscle mass, respectively. Furthermore, Gαi2 over-expression prevented AAV:β2-AR mediated hypertrophy. Introduction of the non-muscle Gαs isoform, GαsXL elicited hypertrophy comparable to that achieved by AAV:β2-AR. Moreover, GαsXL gene delivery was found to be capable of inducing hypertrophy in the muscles of mice lacking functional β1- and β2-ARs. These findings demonstrate that gene therapy-based interventions targeting the β2-AR pathway can promote skeletal muscle hypertrophy independent of ligand administration, and highlight novel methods for potentially modulating muscle mass in settings of disease.
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