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Zhao Z, Yang Y, Liu P, Yan T, Li R, Pan C, Li Y, Lan X. A Critical Functional Missense Mutation (T117M) in Sheep MC4R Gene Significantly Leads to Gain-of-Function. Animals (Basel) 2024; 14:2207. [PMID: 39123733 DOI: 10.3390/ani14152207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2024] [Revised: 07/26/2024] [Accepted: 07/27/2024] [Indexed: 08/12/2024] Open
Abstract
The melanocortin 4 receptor (MC4R) gene plays a central role in regulating energy homeostasis and food intake in livestock, thereby affecting their economic worth and growth. In a previous study, the p.T117M mutation in the sheep MC4R gene, which leads to the transition of threonine to methionine, was found to affect the body weight at six months and the average daily gain in Hu sheep. However, there are still limited studies on the frequency of the sheep p.T117M missense mutation globally, and the underlying cellular mechanism remains elusive. Therefore, this study first used WGS to investigate the distribution of the MC4R gene p.T117M mutation in 652 individuals across 22 breeds worldwide. The results showed that the mutation frequency was higher in European breeds compared with Chinese sheep breeds, particularly in Poll Dorset sheep (mutation frequency > 0.5). The p.T117M mutation occurs in the first extracellular loop of MC4R. Mechanistically, the basal activity of the mutated receptor is significantly increased. Specifically, upon treatment with α-MSH and ACTH ligands, the cAMP and MAPK/ERK signaling activation of M117 MC4R is enhanced. These results indicate that the T117M mutation may change the function of the gene by increasing the constitutive activity and signaling activation of cAMP and MAPK/ERK, and, thus, may regulate the growth traits of sheep. In conclusion, this study delved into the global distribution and underlying cellular mechanisms of the T117M mutation of the MC4R gene, establishing a scientific foundation for breeding sheep with superior growth, thereby contributing to the advancement of the sheep industry.
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Affiliation(s)
- Ziyi Zhao
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Yuta Yang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Peiyao Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Taotao Yan
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Ran Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Chuanying Pan
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Yang Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
| | - Xianyong Lan
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China
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2
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Anthofer L, Gmach P, Uretmen Kagiali ZC, Kleinau G, Rotter J, Opitz R, Scheerer P, Beck-Sickinger AG, Wolf P, Biebermann H, Bechmann I, Kühnen P, Krude H, Paisdzior S. Melanocortin-4 Receptor PLC Activation Is Modulated by an Interaction with the Monocarboxylate Transporter 8. Int J Mol Sci 2024; 25:7565. [PMID: 39062808 PMCID: PMC11277258 DOI: 10.3390/ijms25147565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/05/2024] [Accepted: 07/06/2024] [Indexed: 07/28/2024] Open
Abstract
The melanocortin-4 receptor (MC4R) is a key player in the hypothalamic leptin-melanocortin pathway that regulates satiety and hunger. MC4R belongs to the G protein-coupled receptors (GPCRs), which are known to form heterodimers with other membrane proteins, potentially modulating receptor function or characteristics. Like MC4R, thyroid hormones (TH) are also essential for energy homeostasis control. TH transport across membranes is facilitated by the monocarboxylate transporter 8 (MCT8), which is also known to form heterodimers with GPCRs. Based on the finding in single-cell RNA-sequencing data that both proteins are simultaneously expressed in hypothalamic neurons, we investigated a putative interplay between MC4R and MCT8. We developed a novel staining protocol utilizing a fluorophore-labeled MC4R ligand and demonstrated a co-localization of MC4R and MCT8 in human brain tissue. Using in vitro assays such as BRET, IP1, and cAMP determination, we found that MCT8 modulates MC4R-mediated phospholipase C activation but not cAMP formation via a direct interaction, an effect that does not require a functional MCT8 as it was not altered by a specific MCT8 inhibitor. This suggests an extended functional spectrum of MCT8 as a GPCR signaling modulator and argues for the investigation of further GPCR-protein interactions with hitherto underrepresented physiological functions.
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Affiliation(s)
- Larissa Anthofer
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
- Institute of Anatomy, Leipzig University, D-04103 Leipzig, Germany
| | - Philipp Gmach
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Zeynep Cansu Uretmen Kagiali
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Gunnar Kleinau
- Group Structural Biology of Cellular Signaling, Institute of Medical Physics and Biophysics, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Jonas Rotter
- Institute of Anatomy, Leipzig University, D-04103 Leipzig, Germany
| | - Robert Opitz
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Patrick Scheerer
- Group Structural Biology of Cellular Signaling, Institute of Medical Physics and Biophysics, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | | | - Philipp Wolf
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, D-04103 Leipzig, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Ingo Bechmann
- Institute of Anatomy, Leipzig University, D-04103 Leipzig, Germany
| | - Peter Kühnen
- Department for Pediatric Endocrinology and Diabetology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Sarah Paisdzior
- Institute of Experimental Pediatric Endocrinology, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
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3
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Cevheroğlu O, Demirbaş B, Öğütcü D, Murat M. ADGRG1, an adhesion G protein-coupled receptor, forms oligomers. FEBS J 2024; 291:2461-2478. [PMID: 38468592 DOI: 10.1111/febs.17117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 01/26/2024] [Accepted: 03/01/2024] [Indexed: 03/13/2024]
Abstract
G protein-coupled receptor (GPCR) oligomerization is a highly debated topic in the field. While initially believed to function as monomers, current literature increasingly suggests that these cell surface receptors, spanning almost all GPCR families, function as homo- or hetero-oligomers. Yet, the functional consequences of these oligomeric complexes remain largely unknown. Adhesion GPCRs (aGPCRs) present an intriguing family of receptors characterized by their large and multi-domain N-terminal fragments (NTFs), intricate activation mechanisms, and the prevalence of numerous splice variants in almost all family members. In the present study, bioluminescence energy transfer (BRET) and Förster resonance energy transfer (FRET) were used to study the homo-oligomerization of adhesion G protein-coupled receptor G1 (ADGRG1; also known as GPR56) and to assess the involvement of NTFs in these receptor complexes. Based on the results presented herein, we propose that ADGRG1 forms 7-transmembrane-driven homo-oligomers on the plasma membrane. Additionally, Stachel motif interactions appear to influence the conformation of these receptor complexes.
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Affiliation(s)
| | - Berkay Demirbaş
- Department of Biological Sciences, Middle East Technical University, Çankaya, Turkey
| | - Dilara Öğütcü
- Department of Biological Sciences, Middle East Technical University, Çankaya, Turkey
| | - Merve Murat
- Department of Biological Sciences, Middle East Technical University, Çankaya, Turkey
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4
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Liu R, Friedrich M, Hemmen K, Jansen K, Adolfi MC, Schartl M, Heinze KG. Dimerization of melanocortin 4 receptor controls puberty onset and body size polymorphism. Front Endocrinol (Lausanne) 2023; 14:1267590. [PMID: 38027153 PMCID: PMC10667928 DOI: 10.3389/fendo.2023.1267590] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
Xiphophorus fish exhibit a clear phenotypic polymorphism in puberty onset and reproductive strategies of males. In X. nigrensis and X. multilineatus, puberty onset is genetically determined and linked to a melanocortin 4 receptor (Mc4r) polymorphism of wild-type and mutant alleles on the sex chromosomes. We hypothesized that Mc4r mutant alleles act on wild-type alleles by a dominant negative effect through receptor dimerization, leading to differential intracellular signaling and effector gene activation. Depending on signaling strength, the onset of puberty either occurs early or is delayed. Here, we show by Förster Resonance Energy Transfer (FRET) that wild-type Xiphophorus Mc4r monomers can form homodimers, but also heterodimers with mutant receptors resulting in compromised signaling which explains the reduced Mc4r signaling in large males. Thus, hetero- vs. homo- dimerization seems to be the key molecular mechanism for the polymorphism in puberty onset and body size in male fish.
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Affiliation(s)
- Ruiqi Liu
- Molecular Microscopy, Rudolf Virchow Center for Integrative and Translation Bioimaging, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
- Developmental Biochemistry, Biocenter, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
| | - Mike Friedrich
- Molecular Microscopy, Rudolf Virchow Center for Integrative and Translation Bioimaging, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
| | - Katherina Hemmen
- Molecular Microscopy, Rudolf Virchow Center for Integrative and Translation Bioimaging, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
| | - Kerstin Jansen
- Molecular Microscopy, Rudolf Virchow Center for Integrative and Translation Bioimaging, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
| | - Mateus C. Adolfi
- Developmental Biochemistry, Biocenter, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
| | - Manfred Schartl
- Developmental Biochemistry, Biocenter, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX, United States
| | - Katrin G. Heinze
- Molecular Microscopy, Rudolf Virchow Center for Integrative and Translation Bioimaging, Julius-Maximilians-Universität Würzburg (JMU), Wuerzburg, Germany
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5
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Wei R, Li D, Jia S, Chen Y, Wang J. MC4R in Central and Peripheral Systems. Adv Biol (Weinh) 2023; 7:e2300035. [PMID: 37043700 DOI: 10.1002/adbi.202300035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/25/2023] [Indexed: 04/14/2023]
Abstract
Obesity has emerged as a critical and urgent health burden during the current global pandemic. Among multiple genetic causes, melanocortin receptor-4 (MC4R), involved in food intake and energy metabolism regulation through various signaling pathways, has been reported to be the lead genetic factor in severe and early onset obesity and hyperphagia disorders. Most previous studies have illustrated the roles of MC4R signaling in energy intake versus expenditure in the central system, while some evidence indicates that MC4R is also expressed in peripheral systems, such as the gut and endocrine organs. However, its physiopathological function remains poorly defined. This review aims to depict the central and peripheral roles of MC4R in energy metabolism and endocrine hormone homeostasis, the diversity of phenotypes, biased downstream signaling caused by distinct MC4R mutations, and current drug development targeting the receptor.
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Affiliation(s)
- Ran Wei
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
- Department of Endocrinology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, 200240, China
| | - Danjie Li
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Sheng Jia
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Yuhong Chen
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Jiqiu Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
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6
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Tong H, Shao G, Wang L, Li J, Wang T, Zhang L, Lv Y, Ye F, Fu C, Jin Y. Association of a single amino acid replacement with dorsal pigmentation in a lizard from the Qinghai-Tibetan Plateau. Int J Biol Macromol 2023; 242:124907. [PMID: 37230451 DOI: 10.1016/j.ijbiomac.2023.124907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/08/2023] [Accepted: 05/13/2023] [Indexed: 05/27/2023]
Abstract
Reptiles can evolve adaptive colors in different environments, but relatively little is known about the genetic mechanisms. Here, we identified the MC1R gene and its association with intraspecific color variation in the lizard Phrynocephalus erythrurus. Analysis of the MC1R sequence in 143 individuals from dark South Qiangtang Plateau (SQP) and light North Qiangtang plateau (NQP) populations, revealed two amino acid sites that showed significant differences in frequency between two areas. One SNP, corresponding to Glu183Lys residue, was found to be a highly significant outlier and differentially fixed for SQP and NQP populations. This residue is located in an extracellular area in the second small extracellular loop within the secondary structure of MC1R, which represents an "attachment pocket" part of the 3D structure. Cytological expression of MC1R alleles with the Glu183Lys replacement showed a 39 % increase in intracellular agonist-induced cyclic AMP levels and a 23.18 % greater cell surface expression of MC1R protein in the SQP relative to the NQP allele. Further in silico 3D modeling and in vitro binding experiments indicated a higher MC1R-α-MSH binding for the SQP allele, and elevated melanin synthesis. We provide an overview of how a single amino acid replacement leads to fundamental changes in MC1R function, and hence shapes variation in dorsal pigmentation in lizards from different environments.
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Affiliation(s)
- Haojie Tong
- College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Gang Shao
- College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Leijie Wang
- College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Jiasheng Li
- College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Tao Wang
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Lun Zhang
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yudie Lv
- College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Fei Ye
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Caiyun Fu
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yuanting Jin
- College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China.
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7
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Reininghaus N, Paisdzior S, Höpfner F, Jyrch S, Cetindag C, Scheerer P, Kühnen P, Biebermann H. A Setmelanotide-like Effect at MC4R Is Achieved by MC4R Dimer Separation. Biomolecules 2022; 12:biom12081119. [PMID: 36009013 PMCID: PMC9405727 DOI: 10.3390/biom12081119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 01/22/2023] Open
Abstract
Melanocortin 4 receptor (MC4R) is part of the leptin-melanocortin pathway and plays an essential role in mediating energy homeostasis. Mutations in the MC4R are the most frequent monogenic cause for obesity. Due to increasing numbers of people with excess body weight, the MC4R has become a target of interest in the search of treatment options. We have previously reported that the MC4R forms homodimers, affecting receptor Gs signaling properties. Recent studies introducing setmelanotide, a novel synthetic MC4R agonist, suggest a predominant role of the Gq/11 pathway regarding weight regulation. In this study, we analyzed effects of inhibiting homodimerization on Gq/11 signaling using previously reported MC4R/CB1R chimeras. NanoBRETTM studies to determine protein–protein interaction were conducted, confirming decreased homodimerization capacities of chimeric receptors in HEK293 cells. Gq/11 signaling of chimeric receptors was analyzed using luciferase-based reporter gene (NFAT) assays. Results demonstrate an improvement of alpha-MSH-induced NFAT signaling of chimeras, reaching the level of setmelanotide signaling at wild-type MC4R (MC4R-WT). In summary, our study shows that inhibiting homodimerization has a setmelanotide-like effect on Gq/11 signaling, with chimeric receptors presenting increased potency compared to MC4R-WT. These findings indicate the potential of inhibiting MC4R homodimerization as a therapeutic target to treat obesity.
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Affiliation(s)
- Nanina Reininghaus
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Sarah Paisdzior
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Friederike Höpfner
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Sabine Jyrch
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Cigdem Cetindag
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Patrick Scheerer
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, 10117 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, 13353 Berlin, Germany
| | - Peter Kühnen
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Heike Biebermann
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Experimental Pediatric Endocrinology, Augustenburger Platz 1, 13353 Berlin, Germany
- Correspondence:
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AbouHashem N, Al-Shafai K, Al-Shafai M. The genetic elucidation of monogenic obesity in the Arab world: a systematic review. J Pediatr Endocrinol Metab 2022; 35:699-707. [PMID: 35437977 DOI: 10.1515/jpem-2021-0710] [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: 11/24/2021] [Accepted: 03/21/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Investigation of monogenic obesity (MO), a rare condition caused by a single gene variant(s), especially in consanguineous populations, is a powerful approach for obtaining novel insights into the genetic alterations involved. Here, we present a systematic review of the genetics of MO in the 22 Arab countries and apply protein modeling in silico to the missense variants reported. METHODS We searched four literature databases (PubMed, Web of Science, Science Direct and Scopus) from the time of their first creation until December 2020, utilizing broad search terms to capture all genetic studies related to MO in the Arab countries. Only articles published in peer-reviewed journals involving subjects from at least one of the 22 Arab countries and dealing with genetic variants related to MO were included. Protein modelling of the variants identified was performed using PyMOL. RESULTS The 30 cases with severe early-onset obesity identified in 13 studies carried 14 variants in five genes (LEP, LEPR, POMC, MC4R and CPE). All of these variants were pathogenic, homozygous and carried by members of consanguineous families. CONCLUSION Despite the elevated presence of consanguinity in the Arab countries, the genetic origins of MO remain largely unexplained and require additional studies, both of a genetic and functional character.
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Affiliation(s)
- Nadien AbouHashem
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | | | - Mashael Al-Shafai
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
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Association of ITPA gene polymorphisms with adverse effects of AZA/6-MP administration: a systematic review and meta-analysis. THE PHARMACOGENOMICS JOURNAL 2022; 22:39-54. [PMID: 35034963 DOI: 10.1038/s41397-021-00255-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/24/2021] [Accepted: 09/20/2021] [Indexed: 02/07/2023]
Abstract
Azathioprine (AZA) and its metabolite, mercaptopurine (6-MP), are widely used immunosuppressant drugs. Polymorphisms in genes implicated in AZA/6-MP metabolism, reportedly, could account in part for their potential toxicity. In the present study we performed a systematic review and a meta-analysis, comprising 30 studies and 3582 individuals, to investigate the putative genetic association of two inosine triphosphatase (ITPA) polymorphisms with adverse effects in patients treated with AZA/6-MP. We found that rs1127354 is associated with neutropenia in general populations and in children (OR: 2.39, 95%CI: 1.97-2.90, and OR: 2.43, 95%CI: 2.12-2.79, respectively), and with all adverse effects tested herein in adult populations (OR: 2.12, 95%CI: 1.22-3.69). We also found that rs7270101 is associated with neutropenia and leucopenia in all-ages populations (OR: 2.93, 95%CI: 2.36-3.63, and OR: 2.82, 95%CI: 1.76-4.50, respectively) and with all adverse effects tested herein in children (OR: 1.74, 95%CI: 1.06-2.87). Stratification according to background disease, in combination with multiple comparisons corrections, verified neutropenia to be associated with both polymorphisms, in acute lymphoblastic leukemia (ALL) patients. These findings suggest that ITPA polymorphisms could be used as predictive biomarkers for adverse effects of thiopurine drugs to eliminate intolerance in ALL patients and clarify dosing in patients with different ITPA variants.
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10
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Liu T, Ji RL, Tao YX. Naturally occurring mutations in G protein-coupled receptors associated with obesity and type 2 diabetes mellitus. Pharmacol Ther 2021; 234:108044. [PMID: 34822948 DOI: 10.1016/j.pharmthera.2021.108044] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/15/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of membrane receptors involved in the regulation of almost all known physiological processes. Dysfunctions of GPCR-mediated signaling have been shown to cause various diseases. The prevalence of obesity and type 2 diabetes mellitus (T2DM), two strongly associated disorders, is increasing worldwide, with tremendous economical and health burden. New safer and more efficacious drugs are required for successful weight reduction and T2DM treatment. Multiple GPCRs are involved in the regulation of energy and glucose homeostasis. Mutations in these GPCRs contribute to the development and progression of obesity and T2DM. Therefore, these receptors can be therapeutic targets for obesity and T2DM. Indeed some of these receptors, such as melanocortin-4 receptor and glucagon-like peptide 1 receptor, have provided important new drugs for treating obesity and T2DM. This review will focus on the naturally occurring mutations of several GPCRs associated with obesity and T2DM, especially incorporating recent large genomic data and insights from structure-function studies, providing leads for future investigations.
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Affiliation(s)
- Ting Liu
- Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, United States
| | - Ren-Lei Ji
- Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, United States.
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Kim M, Jo S, Jeong JH, Kim Y. Optimized High-Yield Purification of Obesity-Associated Melanocortin 4 Receptor. Protein Pept Lett 2021; 28:63-73. [PMID: 32484077 DOI: 10.2174/0929866527666200525162928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/26/2020] [Accepted: 04/30/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Obesity has emerged as a global public health challenge associated with increased risk of hyperlipidemia and hypertension. It contributes to high sympathetic activity and increased catecholamine levels. The hypothalamic melanocortin system is known to regulate the energy homeostasis. The role of melanocortin 4 receptor (MC4R) has been demonstrated pharmacologically and in animal studies, which showed that severe obesity in MC4R knockout mice was caused by increased food intake and decreased energy consumption. Over 70 multiple different mis- -sense and nonsense mutations in hMC4R have been found at a high frequency of 2-8% in severe early onset or hereditary obesity. The single amino acid variation (D90N) located in the second transmembrane domain (TM2) of MC4R results in accelerated growth and childhood onset obesity. Interestingly, the functional characterization of D90N hMC4R mutant TM2 (m-hMC4R-TM2) revealed normal cell surface expression and binding with agonist similar to the hMC4R wild-type TM2 (wt-hMC4R-TM2) but loss of signal transduction mediated via Gs/adenylyl cyclase activation. It is essential to delineate the three-dimensional structure of MC4Rs in order to elucidate their functional aspects. OBJECTIVE In this study, we demonstrate the optimized expression and isolation of wt/m-hMC4R-TM2 proteins under different chemical cleavage reaction times and purification procedures via SDS precipitation. The solid-state NMR spectroscopy was carried out to study the structure of wt/m-hMC4R- TM2 protein in the anisotropic phospholipid bicelles. METHODS The KSI-wt/m-hMC4R-TM2 fusion proteins developed in cell culture with LB medium. In order to isolate the expressed fusion protein from the cell, ultrasonication, Ni-NTA affinity chromatography, dialysis, and lyophilization techniques were used. Then, to obtain a protein with higher purity and higher yield, the CNBr chemical cleavage time was subdivided into 30 minutes, 1 h, 2 h, 3 h, and 4 h. Purification process was performed using FPLC, and 100 mM KCl and dialysis were used to remove the SDS. CD spectrometer, MALDI-TOF, solution-state NMR, and solid-state NMR were used to confirmed purity and structure of the wt/m-hMC4R-TM2. RESULTS The precipitation method was used to remove the SDS bound to proteins as KCl-SDS. We optimized the 2 h cleavage reaction times for both wt-hMC4R-TM2 and m-hMC4R-TM2 depending on the purity based on mass spectra and 1H-15N HSQC spectra and the yield after final purification. The 1D 1H-15N CP (Cross polarization) solid-state NMR spectra suggest that the wt/m-hMC4R- TM2 undergo rotational diffusion around a perpendicular axis along the bilayer normal. CONCLUSION We expressed wt/m-hMC4R-TM2 in E.coli and optimized the isolation and purification process, especially CNBr chemical cleavage time. The efficiency of KCl-SDS precipitation was confirmed via MALDI-TOF MS and the pure proteins obtained using this method were characterized by CD spectroscopy and solution-state NMR. The results of 1H-15N HSQC spectra in solution- state NMR also show the probability for structural studies. The 1D 1H-15N CP solid-state NMR spectra indicate that most of the residues in both the wt/m-hMC4R-TM2 peptides are integrated into the membrane.
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Affiliation(s)
- Minseon Kim
- Department of Chemistry, Hankuk University of Foreign Studies, Mohyeon, Yongin, 17035, Korea
| | - Soyeon Jo
- Department of Chemistry, Hankuk University of Foreign Studies, Mohyeon, Yongin, 17035, Korea
| | - Ji-Ho Jeong
- Department of Chemistry, Hankuk University of Foreign Studies, Mohyeon, Yongin, 17035, Korea
| | - Yongae Kim
- Department of Chemistry, Hankuk University of Foreign Studies, Mohyeon, Yongin, 17035, Korea
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Brouwers B, de Oliveira EM, Marti-Solano M, Monteiro FBF, Laurin SA, Keogh JM, Henning E, Bounds R, Daly CA, Houston S, Ayinampudi V, Wasiluk N, Clarke D, Plouffe B, Bouvier M, Babu MM, Farooqi IS, Mokrosiński J. Human MC4R variants affect endocytosis, trafficking and dimerization revealing multiple cellular mechanisms involved in weight regulation. Cell Rep 2021; 34:108862. [PMID: 33761344 PMCID: PMC7994375 DOI: 10.1016/j.celrep.2021.108862] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/29/2021] [Accepted: 02/19/2021] [Indexed: 12/13/2022] Open
Abstract
The Melanocortin-4 Receptor (MC4R) plays a pivotal role in energy homeostasis. We used human MC4R mutations associated with an increased or decreased risk of obesity to dissect mechanisms that regulate MC4R function. Most obesity-associated mutations impair trafficking to the plasma membrane (PM), whereas obesity-protecting mutations either accelerate recycling to the PM or decrease internalization, resulting in enhanced signaling. MC4R mutations that do not affect canonical Gαs protein-mediated signaling, previously considered to be non-pathogenic, nonetheless disrupt agonist-induced internalization, β-arrestin recruitment, and/or coupling to Gαs, establishing their causal role in severe obesity. Structural mapping reveals ligand-accessible sites by which MC4R couples to effectors and residues involved in the homodimerization of MC4R, which is disrupted by multiple obesity-associated mutations. Human genetic studies reveal that endocytosis, intracellular trafficking, and homodimerization regulate MC4R function to a level that is physiologically relevant, supporting the development of chaperones, agonists, and allosteric modulators of MC4R for weight loss therapy.
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Affiliation(s)
- Bas Brouwers
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Edson Mendes de Oliveira
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | | | - Fabiola B F Monteiro
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Suli-Anne Laurin
- Institute for Research in Immunology and Cancer, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Julia M Keogh
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Elana Henning
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Rebecca Bounds
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Carole A Daly
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Shane Houston
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Vikram Ayinampudi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Natalia Wasiluk
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - David Clarke
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Bianca Plouffe
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Michel Bouvier
- Institute for Research in Immunology and Cancer, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - M Madan Babu
- MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Structural Biology and Center for Data Driven Discovery, St Jude Children's Research Hospital, Memphis, TN, USA
| | - I Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
| | - Jacek Mokrosiński
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
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13
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René P, Lanfray D, Richard D, Bouvier M. Pharmacological chaperone action in humanized mouse models of MC4R-linked obesity. JCI Insight 2021; 6:132778. [PMID: 33434184 PMCID: PMC7934941 DOI: 10.1172/jci.insight.132778] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/07/2021] [Indexed: 11/17/2022] Open
Abstract
MC4R mutations represent the largest monogenic cause of obesity, resulting mainly from receptor misfolding and intracellular retention by the cellular quality control system. The present study aimed at determining whether pharmacological chaperones (PCs) that restore folding and plasma membrane trafficking by stabilizing near native protein conformation may represent valid therapeutic avenues for the treatment of melanocortin type 4 receptor–linked (MC4R-linked) obesity. To test the therapeutic PC potential, we engineered humanized MC4R (hMC4R) mouse models expressing either the WT human MC4R or a prevalent obesity-causing mutant (R165W). Administration of a PC able to rescue cell surface expression and functional activity of R165W-hMC4R in cells restored the anorexigenic response of the R165W-hMC4R obese mice to melanocortin agonist, providing a proof of principle for the therapeutic potential of MC4R-targeting PCs in vivo. Interestingly, the expression of the WT-hMC4R in mice revealed lower sensitivity of the human receptor to α–melanocyte-stimulating hormone (α-MSH) but not β-MSH or melanotan II, resulting in a lower penetrance obese phenotype in the WT-hMC4R versus R165W-hMC4R mice. In conclusion, we created 2 new obesity models, a hypomorphic highlighting species differences and an amorphic providing a preclinical model to test the therapeutic potential of PCs to treat MC4R-linked obesity.
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Affiliation(s)
- Patricia René
- Départment de Biochimie et de Médecine Moléculaire, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | | | - Denis Richard
- CRIUCPQ, Université Laval, Québec City, Québec, Canada
| | - Michel Bouvier
- Départment de Biochimie et de Médecine Moléculaire, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
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Yang LK, Hou ZS, Tao YX. Biased signaling in naturally occurring mutations of G protein-coupled receptors associated with diverse human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:165973. [PMID: 32949766 PMCID: PMC7722056 DOI: 10.1016/j.bbadis.2020.165973] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) play critical roles in transmitting a variety of extracellular signals into the cells and regulate diverse physiological functions. Naturally occurring mutations that result in dysfunctions of GPCRs have been known as the causes of numerous diseases. Significant progresses have been made in elucidating the pathophysiology of diseases caused by mutations. The multiple intracellular signaling pathways, such as G protein-dependent and β-arrestin-dependent signaling, in conjunction with recent advances on biased agonism, have broadened the view on the molecular mechanism of disease pathogenesis. This review aims to briefly discuss biased agonism of GPCRs (biased ligands and biased receptors), summarize the naturally occurring GPCR mutations that cause biased signaling, and propose the potential pathophysiological relevance of biased mutant GPCRs associated with various endocrine diseases.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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15
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Hypothalamic Pomc Neurons Innervate the Spinal Cord and Modulate the Excitability of Premotor Circuits. Curr Biol 2020; 30:4579-4593.e7. [PMID: 32976803 DOI: 10.1016/j.cub.2020.08.103] [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: 11/05/2019] [Revised: 07/30/2020] [Accepted: 08/27/2020] [Indexed: 12/20/2022]
Abstract
Locomotion requires energy, yet animals need to increase locomotion in order to find and consume food in energy-deprived states. While such energy homeostatic coordination suggests brain origin, whether the central melanocortin 4 receptor (Mc4r) system directly modulates locomotion through motor circuits is unknown. Here, we report that hypothalamic Pomc neurons in zebrafish and mice have long-range projections into spinal cord regions harboring Mc4r-expressing V2a interneurons, crucial components of the premotor networks. Furthermore, in zebrafish, Mc4r activation decreases the excitability of spinal V2a neurons as well as swimming and foraging, while systemic or V2a neuron-specific blockage of Mc4r promotes locomotion. In contrast, in mice, electrophysiological recordings revealed that two-thirds of V2a neurons in lamina X are excited by the Mc4r agonist α-MSH, and acute inhibition of Mc4r signaling reduces locomotor activity. In addition, we found other Mc4r neurons in spinal lamina X that are inhibited by α-MSH, which is in line with previous studies in rodents where Mc4r agonists reduced locomotor activity. Collectively, our studies identify spinal V2a interneurons as evolutionary conserved second-order neurons of the central Mc4r system, providing a direct anatomical and functional link between energy homeostasis and locomotor control systems. The net effects of this modulatory system on locomotor activity can vary between different vertebrate species and, possibly, even within one species. We discuss the biological sense of this phenomenon in light of the ambiguity of locomotion on energy balance and the different living conditions of the different species.
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16
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Liu R, Du K, Ormanns J, Adolfi MC, Schartl M. Melanocortin 4 receptor signaling and puberty onset regulation in Xiphophorus swordtails. Gen Comp Endocrinol 2020; 295:113521. [PMID: 32470471 DOI: 10.1016/j.ygcen.2020.113521] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/15/2020] [Accepted: 05/22/2020] [Indexed: 01/01/2023]
Abstract
Fish of the genus Xiphophorus provide a prominent example of genetic control of male body size and reproductive tactics. In X.nigrensis and X.multilineatus, puberty onset and body length are determined by melanocortin 4 receptor (Mc4r) allelic and copy number variations which were proposed to fine-tune the signaling output of the system. Accessory protein Mrap2 is required for growth across species by affecting Mc4r signaling. The molecular mechanism how Mc4r signaling controls puberty regulation in Xiphophorus and whether the interaction with Mrap2 is also involved was so far unclear. Hence, we examined Mc4r and Mrap2 in X.nigrensis and X.multilineatus, in comparison to a more distantly related species, X.hellerii. mc4r and mrap2 transcripts co-localized in the hypothalamus and preoptic regions in large males, small males and females of X.nigrensis, with similar signal strength for mrap2 but higher expression of mc4r in large males. This overexpression is constituted by wild-type and one subtype of mutant alleles. In vitro studies revealed that Mrap2 co-expressed with Mc4r increased cAMP production but did not change EC50. Cells co-expressing the wild-type and one mutant allele showed lower cAMP signaling than Mc4r wild-type cells. This indicates a role of Mc4r alleles, but not Mrap2, in puberty signaling. Different from X.nigrensis and X.multilineatus, X.hellerii has only wild-type alleles, but also shows a puberty onset and body length polymorphism, despite the absence of mutant alleles. Like in the two other species, mc4r and mrap2 transcripts colocalized and mc4r is expressed at substantially higher levels in large males. This demonstrates that puberty and growth regulation mechanism may not be identical even within same genus.
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MESH Headings
- Adaptor Proteins, Signal Transducing/metabolism
- Alleles
- Amino Acid Sequence
- Animals
- Cyprinodontiformes/genetics
- Cyprinodontiformes/metabolism
- DNA Copy Number Variations/genetics
- Female
- Gene Expression Regulation, Developmental
- Male
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Sexual Maturation/physiology
- Signal Transduction
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Affiliation(s)
- Ruiqi Liu
- Physiological Chemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Kang Du
- Physiological Chemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany; Developmental Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Jenny Ormanns
- Physiological Chemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Mateus C Adolfi
- Physiological Chemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany; Developmental Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Manfred Schartl
- Physiological Chemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany; Developmental Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany; The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX, USA.
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17
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Structural Complexity and Plasticity of Signaling Regulation at the Melanocortin-4 Receptor. Int J Mol Sci 2020; 21:ijms21165728. [PMID: 32785054 PMCID: PMC7460885 DOI: 10.3390/ijms21165728] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
The melanocortin-4 receptor (MC4R) is a class A G protein-coupled receptor (GPCR), essential for regulation of appetite and metabolism. Pathogenic inactivating MC4R mutations are the most frequent cause of monogenic obesity, a growing medical and socioeconomic problem worldwide. The MC4R mediates either ligand-independent or ligand-dependent signaling. Agonists such as α-melanocyte-stimulating hormone (α-MSH) induce anorexigenic effects, in contrast to the endogenous inverse agonist agouti-related peptide (AgRP), which causes orexigenic effects by suppressing high basal signaling activity. Agonist action triggers the binding of different subtypes of G proteins and arrestins, leading to concomitant induction of diverse intracellular signaling cascades. An increasing number of experimental studies have unraveled molecular properties and mechanisms of MC4R signal transduction related to physiological and pathophysiological aspects. In addition, the MC4R crystal structure was recently determined at 2.75 Å resolution in an inactive state bound with a peptide antagonist. Underpinned by structural homology models of MC4R complexes simulating a presumably active-state conformation compared to the structure of the inactive state, we here briefly summarize the current understanding and key players involved in the MC4R switching process between different activity states. Finally, these perspectives highlight the complexity and plasticity in MC4R signaling regulation and identify gaps in our current knowledge.
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18
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Tao YX. Molecular chaperones and G protein-coupled receptor maturation and pharmacology. Mol Cell Endocrinol 2020; 511:110862. [PMID: 32389798 DOI: 10.1016/j.mce.2020.110862] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) are highly conserved versatile signaling molecules located at the plasma membrane that respond to diverse extracellular signals. They regulate almost all physiological processes in the vertebrates. About 35% of current drugs target these receptors. Mutations in these genes have been identified as causes of numerous diseases. The seven transmembrane domain structure of GPCRs implies that the folding of these transmembrane proteins is extremely complicated and difficult. Indeed, many wild type GPCRs are not folded optimally. The most common defect in genetic diseases caused by GPCR mutations is misfolding and failure to reach the plasma membrane where it functions. General molecular chaperones aid the folding of all proteins, including GPCRs, by preventing aggregation, promoting folding and disaggregating small aggregates. Some GPCRs need additional receptor-specific chaperones to assist their folding. Many of these receptor-specific chaperones interact with additional receptors and alter receptor pharmacology, expanding the understanding of these chaperone proteins.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849-5519, USA.
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19
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Differential Signaling Profiles of MC4R Mutations with Three Different Ligands. Int J Mol Sci 2020; 21:ijms21041224. [PMID: 32059383 PMCID: PMC7072973 DOI: 10.3390/ijms21041224] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/21/2022] Open
Abstract
The melanocortin 4 receptor (MC4R) is a key player in hypothalamic weight regulation and energy expenditure as part of the leptin–melanocortin pathway. Mutations in this G protein coupled receptor (GPCR) are the most common cause for monogenetic obesity, which appears to be mediated by changes in the anorectic action of MC4R via GS-dependent cyclic adenosine-monophosphate (cAMP) signaling as well as other signaling pathways. To study potential bias in the effects of MC4R mutations between the different signaling pathways, we investigated three major MC4R mutations: a GS loss-of-function (S127L) and a GS gain-of-function mutant (H158R), as well as the most common European single nucleotide polymorphism (V103I). We tested signaling of all four major G protein families plus extracellular regulated kinase (ERK) phosphorylation and β-arrestin2 recruitment, using the two endogenous agonists, α- and β-melanocyte stimulating hormone (MSH), along with a synthetic peptide agonist (NDP-α-MSH). The S127L mutation led to a full loss-of-function in all investigated pathways, whereas V103I and H158R were clearly biased towards the Gq/11 pathway when challenged with the endogenous ligands. These results show that MC4R mutations can cause vastly different changes in the various MC4R signaling pathways and highlight the importance of a comprehensive characterization of receptor mutations.
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20
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Link R, Veiksina S, Tahk MJ, Laasfeld T, Paiste P, Kopanchuk S, Rinken A. The constitutive activity of melanocortin-4 receptors in cAMP pathway is allosterically modulated by zinc and copper ions. J Neurochem 2019; 153:346-361. [PMID: 31792980 DOI: 10.1111/jnc.14933] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 11/06/2019] [Accepted: 11/29/2019] [Indexed: 01/25/2023]
Abstract
Melanocortin-4 receptors (MC4 R) are unique among G-protein-coupled receptors (GPCRs) as they have endogenous ligands that can exhibit inverse agonistic properties in the case of elevated basal activity. It is known that the constitutive activity of GPCRs strongly affects the ligand-dependent physiological responses, but little is known about these regulatory mechanisms. Since several metal ions have been shown to be important modulators of the signal transduction of GPCRs, we hypothesized that metal ions regulate the basal activity of MC4 Rs. Implementation of a fluorescence anisotropy assay and novel redshifted fluorescent peptides enabled kinetic characterization of ligand binding to MC4 R expressed on budded baculoviruses. We show that Ca2+ is required for high-affinity ligand binding, but Zn2+ and Cu2+ in the presence of Ca2+ behave as negative allosteric modulators of ligand binding to MC4 R. FRET-based cAMP biosensor was used to measure the activation of MC4 R stably expressed in CHO-K1 cells. At low micromolar concentrations, Zn2+ caused MC4 R-dependent activation of the cAMP pathway, whereas Cu2+ reduced the activity of MC4 R even below the basal level. These findings indicate that at physiologically relevant concentrations can Zn2+ and Cu2+ function as MC4 R agonists or inverse agonists, respectively. This means that depending on the level of constitutive activity induced by Zn2+ ions, the pharmacological effect of orthosteric ligands of MC4 R can be switched from a partial to an inverse agonist. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. More information about the Open Science badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Reet Link
- Institute of Chemistry, University of Tartu, Tartu, Estonia
| | - Santa Veiksina
- Institute of Chemistry, University of Tartu, Tartu, Estonia
| | | | - Tõnis Laasfeld
- Institute of Chemistry, University of Tartu, Tartu, Estonia
| | - Päärn Paiste
- Department of Geology, University of Tartu, Tartu, Estonia
| | | | - Ago Rinken
- Institute of Chemistry, University of Tartu, Tartu, Estonia
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Heyder N, Kleinau G, Szczepek M, Kwiatkowski D, Speck D, Soletto L, Cerdá-Reverter JM, Krude H, Kühnen P, Biebermann H, Scheerer P. Signal Transduction and Pathogenic Modifications at the Melanocortin-4 Receptor: A Structural Perspective. Front Endocrinol (Lausanne) 2019; 10:515. [PMID: 31417496 PMCID: PMC6685040 DOI: 10.3389/fendo.2019.00515] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/15/2019] [Indexed: 12/19/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) can be endogenously activated by binding of melanocyte-stimulating hormones (MSH), which mediates anorexigenic effects. In contrast, the agouti-related peptide (AgRP) acts as an endogenous inverse agonist and suppresses ligand-independent basal signaling activity (orexigenic effects). Binding of ligands to MC4R leads to the activation of different G-protein subtypes or arrestin and concomitant signaling pathways. This receptor is a key protein in the hypothalamic regulation of food intake and energy expenditure and naturally-occurring inactivating MC4R variants are the most frequent cause of monogenic obesity. In general, obesity is a growing problem on a global scale and is of social, medical, and economic relevance. A significant goal is to develop optimized pharmacological tools targeting MC4R without adverse effects. To date, this has not been achieved because of inter alia non-selective ligands across the five functionally different MCR subtypes (MC1-5R). This motivates further investigation of (i) the three-dimensional MC4R structure, (ii) binding mechanisms of various ligands, and (iii) the molecular transfer process of signal transduction, with the aim of understanding how structural features are linked with functional-physiological aspects. Unfortunately, experimentally elucidated structural information is not yet available for the MC receptors, a group of class A G-protein coupled receptors (GPCRs). We, therefore, generated MC4R homology models and complexes with interacting partners to describe approximate structural properties associated with signaling mechanisms. In addition, molecular insights from pathogenic mutations were incorporated to discriminate more precisely their individual malfunction of the signal transfer mechanism.
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Affiliation(s)
- Nicolas Heyder
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gunnar Kleinau
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- *Correspondence: Gunnar Kleinau
| | - Michal Szczepek
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dennis Kwiatkowski
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - David Speck
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lucia Soletto
- Departamento de Fisiología de Peces y Biotecnología, Consejo Superior de Investigaciones Científicas, Instituto de Acuicultura Torre de la Sal, Ribera de Cabanes, Spain
| | - José Miguel Cerdá-Reverter
- Departamento de Fisiología de Peces y Biotecnología, Consejo Superior de Investigaciones Científicas, Instituto de Acuicultura Torre de la Sal, Ribera de Cabanes, Spain
| | - Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Peter Kühnen
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Patrick Scheerer
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22
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Fischer J, Kleinau G, Rutz C, Zwanziger D, Khajavi N, Müller A, Rehders M, Brix K, Worth CL, Führer D, Krude H, Wiesner B, Schülein R, Biebermann H. Evidence of G-protein-coupled receptor and substrate transporter heteromerization at a single molecule level. Cell Mol Life Sci 2018; 75:2227-2239. [PMID: 29290039 PMCID: PMC11105501 DOI: 10.1007/s00018-017-2728-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/17/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
G-protein-coupled receptors (GPCRs) can constitute complexes with non-GPCR integral membrane proteins, while such interaction has not been demonstrated at a single molecule level so far. We here investigated the potential interaction between the thyrotropin receptor (TSHR) and the monocarboxylate transporter 8 (MCT8), a member of the major facilitator superfamily (MFS), using fluorescence cross-correlation spectroscopy (FCCS). Both the proteins are expressed endogenously on the basolateral plasma membrane of the thyrocytes and are involved in stimulation of thyroid hormone production and release. Indeed, we demonstrate strong interaction between both the proteins which causes a suppressed activation of Gq/11 by TSH-stimulated TSHR. Thus, we provide not only evidence for a novel interaction between the TSHR and MCT8, but could also prove this interaction on a single molecule level. Moreover, this interaction forces biased signaling at the TSHR. These results are of general interest for both the GPCR and the MFS research fields.
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Affiliation(s)
- Jana Fischer
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Gunnar Kleinau
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Claudia Rutz
- Protein Trafficking Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Denise Zwanziger
- Division of Laboratory Research, Department of Endocrinology, Diabetology and Metabolism, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Noushafarin Khajavi
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Anne Müller
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Maren Rehders
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany
| | - Klaudia Brix
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany
| | - Catherine L Worth
- Structural Bioinformatics and Protein Design Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125, Berlin, Germany
| | - Dagmar Führer
- Division of Laboratory Research, Department of Endocrinology, Diabetology and Metabolism, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Heiko Krude
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Burkhard Wiesner
- Protein Trafficking Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
- Cellular Imaging Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125, Berlin, Germany
| | - Ralf Schülein
- Protein Trafficking Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany.
| | - Heike Biebermann
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany.
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Habara M, Mori N, Okada Y, Kawasumi K, Nakao N, Tanaka Y, Arai T, Yamamoto I. Molecular characterization of feline melanocortin 4 receptor and melanocortin 2 receptor accessory protein 2. Gen Comp Endocrinol 2018; 261:31-39. [PMID: 29360464 DOI: 10.1016/j.ygcen.2018.01.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/17/2018] [Accepted: 01/17/2018] [Indexed: 01/06/2023]
Abstract
Melanocortin 4 receptor (MC4R), which is a member of the G protein-coupled receptor (GPCR) family, mediates regulation of energy homeostasis upon the binding of α-melanocyte-stimulating hormone (α-MSH) in the central nervous system (CNS). Melanocortin 2 receptor accessory protein 2 (MRAP2) modulates the function of MC4R. We performed cDNA cloning of cat MC4R and MRAP2 and characterized their amino acid sequences, mRNA expression patterns in cat tissues, protein-protein interactions, and functions. We found high sequence homology (>88%) with other mammalian MC4R and MRAP2 encoding 332 and 206 amino acid residues, respectively. Reverse transcription-polymerase chain reaction analysis revealed that cat MC4R and MRAP2 mRNA were expressed highly in the CNS. In CHO-K1 cells transfected with cat MC4R, stimulation with α-MSH increased intracellular cyclic adenosine monophosphate (cAMP) concentration in a dose-dependent manner. Furthermore, the presence of MRAP2 enhanced the cat MC4R-mediated cAMP production. These results suggested that cat MC4R acts as a neuronal mediator in the CNS and that its function is modulated by MRAP2. In addition, our NanoBiT study showed the dynamics of their interactions in living cells; stimulation with α-MSH slightly affected the interaction between MC4R and MRAP2, and did not affect MC4R homodimerization, suggesting that they interact in the basal state and that structural change of MC4R by activation may affect the interaction between MC4R and MRAP2.
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Affiliation(s)
- Makoto Habara
- Department of Basic Veterinary Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan
| | - Nobuko Mori
- Department of Basic Veterinary Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan; Laboratory of Molecular Biomedicine for Pathogenesis, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033, Japan
| | - Yuki Okada
- Department of Basic Veterinary Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan
| | - Koh Kawasumi
- Department of Basic Veterinary Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan
| | - Nobuhiro Nakao
- Laboratory of Animal Physiology, Department of Animal Science, Faculty of Applied Life Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan
| | - Yoshikazu Tanaka
- Department of Veterinary Hygiene, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan
| | - Toshiro Arai
- Department of Basic Veterinary Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan
| | - Ichiro Yamamoto
- Department of Basic Veterinary Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 1808602, Japan.
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Early childhood BMI trajectories in monogenic obesity due to leptin, leptin receptor, and melanocortin 4 receptor deficiency. Int J Obes (Lond) 2018; 42:1602-1609. [PMID: 29568105 DOI: 10.1038/s41366-018-0049-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 12/01/2017] [Accepted: 01/22/2018] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To evaluate whether early childhood body mass index (BMI) is an appropriate indicator for monogenic obesity. METHODS A cohort of n = 21 children living in Germany or Austria with monogenic obesity due to congenital leptin deficiency (group LEP, n = 6), leptin receptor deficiency (group LEPR, n = 6) and primarily heterozygous MC4 receptor deficiency (group MC4R, n = 9) was analyzed. A control group (CTRL) was defined that consisted of n = 22 obese adolescents with no mutation in the above mentioned genes. Early childhood (0-5 years) BMI trajectories were compared between the groups at selected time points. RESULTS The LEP and LEPR group showed a tremendous increase in BMI during the first 2 years of life with all patients displaying a BMI >27 kg/m2 (27.2-38.4 kg/m2) and %BMIP95 (percentage of the 95th percentile BMI for age and sex) >140% (144.8-198.6%) at the age of 2 years and a BMI > 33 kg/m2 (33.3-45.9 kg/m2) and %BMIP95 > 184% (184.1-212.6%) at the age of 5 years. The MC4R and CTRL groups had a later onset of obesity with significantly lower BMI values at both time points (p < 0.01). CONCLUSION As result of the investigation of early childhood BMI trajectories in this pediatric cohort with monogenic obesity we suggest that BMI values >27.0 kg/m2 or %BMIP95 > 140% at the age of 2 years and BMI values >33.0 kg/m2 or %BMIP95 > 184% at the age of 5 years may be useful cut points to identify children who should undergo genetic screening for monogenic obesity due to functionally relevant mutations in the leptin gene or leptin receptor gene.
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26
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Giuranna J, Volckmar AL, Heinen A, Peters T, Schmidt B, Spieker A, Straub H, Grallert H, Müller TD, Antel J, Haußmann U, Klafki H, Liangyou R, Hebebrand J, Hinney A. The Effect of SH2B1 Variants on Expression of Leptin- and Insulin-Induced Pathways in Murine Hypothalamus. Obes Facts 2018; 11:93-108. [PMID: 29631267 PMCID: PMC5981666 DOI: 10.1159/000486962] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/15/2018] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE We aimed to determine the effect of human SH2B1 variants on leptin and insulin signaling, major regulators of energy homeostasis, on the RNA level. METHODS We analyzed the expression of infrequent alleles of seven SH2B1 variants (Arg67Cys, Lys150Arg, Thr175Ala, Thr343Met, Thr484Ala, Ser616Pro and Pro689Leu) in response to insulin or leptin cell stimulation. Two of these were identified in own mutation screens, the others were predicted to be deleterious or to serve as controls. The variants were analyzed in a homologous system of mouse hypothalamic cells. Changes in expression of downstream genes were measured. Student’s t-test for independent samples was applied and effect sizes using Cohen’s d were calculated. RESULTS In 34 of 54 analyzed genes involved in leptin (JAK/STAT or AKT) signaling, variants nominally changed expression. The expression of three genes was considerably increased (p values ≤ 0.001: Gbp2b (67Cys; d = 25.11), Irf9 (689Leu; d = 44.65) and Isg15 (150Arg; d = 20.35)). Of 32 analyzed genes in the insulin signaling pathway, the expression of 10 genes nominally changed (p ≤ 0.05), three resulted in p values ≤ 0.01 ( Cap1 (150Arg; d = 7.48), Mapk1 (343Met; d = –6.80) and Sorbs1 (689Leu; d = 7.82)). CONCLUSION The increased expression of genes in leptin (JAK/STAT or AKT) signaling implies that the main mode of action for human SH2B1 mutations might affect leptin signaling rather than insulin signaling.
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Affiliation(s)
- Johanna Giuranna
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Anna-Lena Volckmar
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany
| | - Anna Heinen
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Triinu Peters
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Börge Schmidt
- Institute for Medical Informatics, Biometry and Epidemiology (IMIBE), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Anne Spieker
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Helena Straub
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Harald Grallert
- Institute of Epidemiology, Helmholtz-Zentrum Munich, Munich, Germany
| | - Timo D. Müller
- Institute of Diabetes and Obesity, Helmholtz-Zentrum Munich, Munich, Germany
| | - Jochen Antel
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ute Haußmann
- Department of Psychiatry and Psychotherapy, Faculty of Medicine, University Hospital Essen, Essen, Germany
| | - Hans Klafki
- Department of Psychiatry and Psychotherapy, Faculty of Medicine, University Hospital Essen, Essen, Germany
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University Göttingen, Göttingen, Germany
| | - Rui Liangyou
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Johannes Hebebrand
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Anke Hinney
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- *Prof. Dr. Anke Hinney, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Wickenburgstraße 21, 45147 Essen, Germany,
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27
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Frühkindlicher BMI-Verlauf bei monogener Adipositas. MED GENET-BERLIN 2017. [DOI: 10.1007/s11825-017-0167-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Zusammenfassung
Hintergrund
Monogene Adipositasformen haben eine geschätzte Prävalenz von 1–5 % in der Gruppe der extrem adipösen Patienten. Bereits im frühen Kindesalter zwischen monogener Adipositas und anderen Adipositasformen zu unterscheiden, stellt eine Herausforderung für Kinderärzte dar. Insbesondere stellt sich die Frage, wann weiterführende Diagnostik indiziert ist.
Fragestellung
Können Body Mass Index (BMI) und BMI-Verlauf als Parameter herangezogen werden, um eine monogene Adipositas auf Basis einer Mutation des Leptin- oder Leptinrezeptorgens frühzeitig zu diagnostizieren?
Material und Methoden
Frühkindliche BMI-Verläufe (0–5 Jahre) von n = 21 Patienten mit monogener Adipositas aufgrund von Leptindefizienz (LEP, n = 6), Leptinrezeptordefizienz (LEPR, n = 6) und MC4-Rezeptordefizienz (MC4R, n = 9) wurden analysiert. BMI-Werte im Alter von 2 und 5 Jahren, Zeitpunkte der Vorsorgen U7 und U9 in Deutschland, wurden zwischen den Gruppen verglichen.
Ergebnisse
Patienten mit funktionellem Leptinmangel oder Leptinrezeptordefekt zeigen den stärksten BMI-Anstieg in den ersten beiden Lebensjahren. Ihr BMI ist im Alter von 2 Jahren >25 kg/m2 [27,2–38,4 kg/m2] und im Alter von 5 Jahren >30 kg/m2 [33,3–45,9 kg/m2]. Bei Patienten mit MC4R-Defekt manifestierte sich die Adipositas zu einem späteren Zeitpunkt mit signifikant niedrigeren BMI-Werten im Alter von 2 bzw. 5 Jahren (p < 0,01).
Diskussion
Unsere Ergebnisse zeigen, dass ein BMI > 25 kg/m2 im Alter von 2 Jahren und ein BMI > 30 kg/m2 im Alter von 5 Jahren Hinweis auf das Vorliegen einer monogenen Adipositas auf Basis einer Mutation des Leptin- oder Leptinrezeptorgens ist. Bei diesen Patienten sollte eine weiterführende Diagnostik (Bestimmung von Leptin, bioaktivem Leptin, Molekulargenetik) frühzeitig erfolgen.
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Ericson MD, Lensing CJ, Fleming KA, Schlasner KN, Doering SR, Haskell-Luevano C. Bench-top to clinical therapies: A review of melanocortin ligands from 1954 to 2016. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2414-2435. [PMID: 28363699 PMCID: PMC5600687 DOI: 10.1016/j.bbadis.2017.03.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
The discovery of the endogenous melanocortin agonists in the 1950s have resulted in sixty years of melanocortin ligand research. Early efforts involved truncations or select modifications of the naturally occurring agonists leading to the development of many potent and selective ligands. With the identification and cloning of the five known melanocortin receptors, many ligands were improved upon through bench-top in vitro assays. Optimization of select properties resulted in ligands adopted as clinical candidates. A summary of every melanocortin ligand is outside the scope of this review. Instead, this review will focus on the following topics: classic melanocortin ligands, selective ligands, small molecule (non-peptide) ligands, ligands with sex-specific effects, bivalent and multivalent ligands, and ligands advanced to clinical trials. Each topic area will be summarized with current references to update the melanocortin field on recent progress. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cody J Lensing
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katlyn A Fleming
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katherine N Schlasner
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Skye R Doering
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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29
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Litt MJ, Okoye GD, Lark D, Cakir I, Moore C, Barber MC, Atkinson J, Fessel J, Moslehi J, Cone RD. Loss of the melanocortin-4 receptor in mice causes dilated cardiomyopathy. eLife 2017; 6:28118. [PMID: 28829041 PMCID: PMC5577919 DOI: 10.7554/elife.28118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/26/2017] [Indexed: 01/04/2023] Open
Abstract
Haploinsufficiency of the melanocortin-4 receptor, the most common monogenetic obesity syndrome in humans, is associated with a reduction in autonomic tone, bradycardia, and incidence of obesity-associated hypertension. Thus, it has been assumed that melanocortin obesity syndrome may be protective with respect to obesity-associated cardiovascular disease. We show here that absence of the melanocortin-4 receptor (MC4R) in mice causes dilated cardiomyopathy, characterized by reduced contractility and increased left ventricular diameter. This cardiomyopathy is independent of obesity as weight matched diet induced obese mice do not display systolic dysfunction. Mc4r cardiomyopathy is characterized by ultrastructural changes in mitochondrial morphology and cardiomyocyte disorganization. Remarkably, testing of myocardial tissue from Mc4r-/- mice exhibited increased ADP stimulated respiratory capacity. However, this increase in respiration correlates with increased reactive oxygen species production - a canonical mediator of tissue damage. Together this study identifies MC4R deletion as a novel and potentially clinically important cause of heart failure.
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Affiliation(s)
- Michael J Litt
- Departments of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States
| | - G Donald Okoye
- Division of Cardiology, Vanderbilt University, Nashville, United States.,Cardio-Oncology Program, Department of Medicine, Vanderbilt University, Nashville, United States
| | - Daniel Lark
- Departments of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States
| | - Isin Cakir
- Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Christy Moore
- Allergy Pulmonary and Critical Care, Vanderbilt University Department of Medicine, Nashville, United States
| | - Mary C Barber
- Division of Cardiology, Vanderbilt University, Nashville, United States.,Cardio-Oncology Program, Department of Medicine, Vanderbilt University, Nashville, United States
| | - James Atkinson
- Department of Pathology, Vanderbilt University Medical Center, Nashville, United States
| | - Josh Fessel
- Allergy Pulmonary and Critical Care, Vanderbilt University Department of Medicine, Nashville, United States
| | - Javid Moslehi
- Division of Cardiology, Vanderbilt University, Nashville, United States.,Cardio-Oncology Program, Department of Medicine, Vanderbilt University, Nashville, United States
| | - Roger D Cone
- Departments of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States.,Life Sciences Institute, University of Michigan, Ann Arbor, United States.,Department of Molecular and Integrative Physiology, University of Michigan School of Medicine, Ann Arbor, United States
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Janovick JA, Spicer TP, Bannister TD, Scampavia L, Conn PM. Pharmacoperone rescue of vasopressin 2 receptor mutants reveals unexpected constitutive activity and coupling bias. PLoS One 2017; 12:e0181830. [PMID: 28767678 PMCID: PMC5540481 DOI: 10.1371/journal.pone.0181830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 07/08/2017] [Indexed: 12/30/2022] Open
Abstract
Pharmacoperones are small molecules that diffuse into cells and rescue misfolded, mistrafficked protein mutants, restoring their function. These substances act with high target specificity, serving as templates to fold (or refold) receptors, enzymes, ion channels or other proteins and enable them to pass the scrutiny of the cellular quality control system ("rescue"). In the present study we demonstrate that a rescued mutant (L83Q) of the vasopressin type 2 receptor (V2R), shows a strong bias for Gs coupling unlike the WT V2 receptor, which couples to both Gs and Gq/11. Failure of the mutant to couple to Gq/11 was not due to a limiting quantity of G-proteins since other Gq/11-coupled receptors (WT V2R, histamine receptor and muscarinic receptor) responded appropriately to their ligands. Transfection with DNA encoding Gq enabled the V2 receptor mutant to couple to this G protein, but only modestly compared with the WT receptor. Fourteen V2R mutant pharmacoperones, of multiple chemical classes, obtained from a high throughput screen of a 660,000 structure library, and one V2R peptidomimetic antagonist rescues L83Q. The rescued mutant shows similar bias with all pharmacoperones identified, suggesting that the bias is intrinsic to the mutant protein's structure, rather than due to the chemical class of the pharmacoperone. In the case of V2R mutant Y128S, rescue with a pharmacoperone revealed constitutive activity, also with bias for Gs, although both IP and cAMP were produced in response to agonist. These results suggest that particular rescued receptor mutants show functional characteristics that differ from the WT receptor; a finding that may be important to consider as pharmacoperones are developed as therapeutic agents.
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Affiliation(s)
- Jo Ann Janovick
- Departments of Internal Medicine and Cell Biology/Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Timothy P. Spicer
- Lead Identification Division, Translational Research Institute and Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida, United States of America
| | - Thomas D. Bannister
- Department of Chemistry, Scripps Research Institute, Jupiter, Florida, United States of America
| | - Louis Scampavia
- Lead Identification Division, Translational Research Institute and Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida, United States of America
| | - P. Michael Conn
- Departments of Internal Medicine and Cell Biology/Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
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31
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Lensing CJ, Adank DN, Wilber SL, Freeman KT, Schnell SM, Speth RC, Zarth AT, Haskell-Luevano C. A Direct in Vivo Comparison of the Melanocortin Monovalent Agonist Ac-His-DPhe-Arg-Trp-NH 2 versus the Bivalent Agonist Ac-His-DPhe-Arg-Trp-PEDG20-His-DPhe-Arg-Trp-NH 2: A Bivalent Advantage. ACS Chem Neurosci 2017; 8:1262-1278. [PMID: 28128928 DOI: 10.1021/acschemneuro.6b00399] [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] [Indexed: 11/29/2022] Open
Abstract
Bivalent ligands targeting putative melanocortin receptor dimers have been developed and characterized in vitro; however, studies of their functional in vivo effects have been limited. The current report compares the effects of homobivalent ligand CJL-1-87, Ac-His-DPhe-Arg-Trp-PEDG20-His-DPhe-Arg-Trp-NH2, to monovalent ligand CJL-1-14, Ac-His-DPhe-Arg-Trp-NH2, on energy homeostasis in mice after central intracerebroventricular (ICV) administration into the lateral ventricle of the brain. Bivalent ligand CJL-1-87 had noteworthy advantages as an antiobesity probe over CJL-1-14 in a fasting-refeeding in vivo paradigm. Treatment with CJL-1-87 significantly decreased food intake compared to CJL-1-14 or saline (50% less intake 2-8 h after treatment). Furthermore, CJL-1-87 treatment decreased the respiratory exchange ratio (RER) without changing the energy expenditure indicating that fats were being burned as the primary fuel source. Additionally, CJL-1-87 treatment significantly lowered body fat mass percentage 6 h after administration (p < 0.05) without changing the lean mass percentage. The bivalent ligand significantly decreased insulin, C-peptide, leptin, GIP, and resistin plasma levels compared to levels after CJL-1-14 or saline treatments. Alternatively, ghrelin plasma levels were significantly increased. Serum stability of CJL-1-87 and CJL-1-14 (T1/2 = 6.0 and 16.8 h, respectively) was sufficient to permit physiological effects. The differences in binding affinity of CJL-1-14 compared to CJL-1-87 are speculated as a possible mechanism for the bivalent ligand's unique effects. We also provide in vitro evidence for the formation of a MC3R-MC4R heterodimer complex, for the first time to our knowledge, that may be an unexploited neuronal molecular target. Regardless of the exact mechanism, the advantageous ability of CJL-1-87 compared to CJL-1-14 to increase in vitro binding affinity, increase the duration of action in spite of decreased serum stability, decrease in vivo food intake, decrease mice's body fat percent, and differentially affect mouse hormone levels demonstrates the distinct characteristics achieved from the current melanocortin agonist bivalent design strategy.
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Affiliation(s)
- Cody J. Lensing
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Danielle N. Adank
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Stacey L. Wilber
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katie T. Freeman
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Sathya M. Schnell
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Robert C. Speth
- College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida 33328-2018, United States
- Department of Pharmacology and Physiology, Georgetown University, Washington, D.C. 20057, United States
| | - Adam T. Zarth
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Masonic Cancer Center, University of Minnesota, 2231 6th Street SE, 2-210 CCRB, Minneapolis, Minnesota 55455, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal
Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Methods used to study the oligomeric structure of G-protein-coupled receptors. Biosci Rep 2017; 37:BSR20160547. [PMID: 28062602 PMCID: PMC5398257 DOI: 10.1042/bsr20160547] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 02/02/2023] Open
Abstract
G-protein-coupled receptors (GPCRs), which constitute the largest family of cell surface receptors, were originally thought to function as monomers, but are now recognized as being able to act in a wide range of oligomeric states and indeed, it is known that the oligomerization state of a GPCR can modulate its pharmacology and function. A number of experimental techniques have been devised to study GPCR oligomerization including those based upon traditional biochemistry such as blue-native PAGE (BN-PAGE), co-immunoprecipitation (Co-IP) and protein-fragment complementation assays (PCAs), those based upon resonance energy transfer, FRET, time-resolved FRET (TR-FRET), FRET spectrometry and bioluminescence resonance energy transfer (BRET). Those based upon microscopy such as FRAP, total internal reflection fluorescence microscopy (TIRFM), spatial intensity distribution analysis (SpIDA) and various single molecule imaging techniques. Finally with the solution of a growing number of crystal structures, X-ray crystallography must be acknowledged as an important source of discovery in this field. A different, but in many ways complementary approach to the use of more traditional experimental techniques, are those involving computational methods that possess obvious merit in the study of the dynamics of oligomer formation and function. Here, we summarize the latest developments that have been made in the methods used to study GPCR oligomerization and give an overview of their application.
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Yang LK, Tao YX. Biased signaling at neural melanocortin receptors in regulation of energy homeostasis. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2486-2495. [PMID: 28433713 DOI: 10.1016/j.bbadis.2017.04.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
The global prevalence of obesity highlights the importance of understanding on regulation of energy homeostasis. The central melanocortin system is an important intersection connecting the neural pathways controlling satiety and energy expenditure to regulate energy homeostasis by sensing and integrating the signals of external stimuli. In this system, neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), play crucial roles in the regulation of energy homeostasis. Recently, multiple intracellular signaling pathways and biased signaling at neural MCRs have been discovered, providing new insights into neural MCR signaling. This review attempts to summarize biased signaling including biased receptor mutants (both naturally occurring and lab-generated) and biased ligands at neural MCRs, and to provide a better understanding of obesity pathogenesis and new therapeutic implications for obesity treatment.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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Huang H, Wang W, Tao YX. Pharmacological chaperones for the misfolded melanocortin-4 receptor associated with human obesity. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2496-2507. [PMID: 28284973 DOI: 10.1016/j.bbadis.2017.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 01/01/2023]
Abstract
The melanocortin-4 receptor (MC4R) plays a vital role in regulating energy homeostasis. Mutations in the MC4R cause early-onset severe obesity. The majority of loss of function MC4R mutants are retained intracellularly, many of which are not terminally misfolded and can be stabilized and targeted to the plasma membrane by different chaperones. Some of the mutants might be functional once coaxed to the cell surface. Molecular chaperones and chemical chaperones correct the misfolding of some mutant MC4Rs. However, their therapeutic application is very limited due to their non-specific mechanism of action and, for chemical chaperone, high dosage needed to be effective. Several pharmacological chaperones have been identified for the MC4R and Ipsen 5i and Ipsen 17 are the most potent and efficacious. Here we provide a comprehensive review on how different approaches have been applied to rescue misfolded MC4R mutants. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Hui Huang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Wei Wang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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Link R, Veiksina S, Rinken A, Kopanchuk S. Characterization of ligand binding to melanocortin 4 receptors using fluorescent peptides with improved kinetic properties. Eur J Pharmacol 2017; 799:58-66. [DOI: 10.1016/j.ejphar.2017.01.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/24/2022]
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Farran B. An update on the physiological and therapeutic relevance of GPCR oligomers. Pharmacol Res 2017; 117:303-327. [PMID: 28087443 DOI: 10.1016/j.phrs.2017.01.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/17/2023]
Abstract
The traditional view on GPCRs held that they function as single monomeric units composed of identical subunits. This notion was overturned by the discovery that GPCRs can form homo- and hetero-oligomers, some of which are obligatory, and can further assemble into receptor mosaics consisting of three or more protomers. Oligomerisation exerts significant impacts on receptor function and physiology, offering a platform for the diversification of receptor signalling, pharmacology, regulation, crosstalk, internalization and trafficking. Given their involvement in the modulation of crucial physiological processes, heteromers could constitute important therapeutic targets for a wide range of diseases, including schizophrenia, Parkinson's disease, substance abuse or obesity. This review aims at depicting the current developments in GPCR oligomerisation research, documenting various class A, B and C GPCR heteromers detected in vitro and in vivo using biochemical and biophysical approaches, as well as recently identified higher-order oligomeric complexes. It explores the current understanding of dimerization dynamics and the possible interaction interfaces that drive oligomerisation. Most importantly, it provides an inventory of the wide range of physiological processes and pathophysiological conditions to which GPCR oligomers contribute, surveying some of the oligomers that constitute potential drug targets. Finally, it delineates the efforts to develop novel classes of ligands that specifically target and tether to receptor oligomers instead of a single monomeric entity, thus ameliorating their ability to modulate GPCR function.
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Affiliation(s)
- Batoul Farran
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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Variants of G protein-coupled receptors: a reappraisal of their role in receptor regulation. Biochem Soc Trans 2016; 44:589-94. [PMID: 27068974 DOI: 10.1042/bst20150239] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 01/11/2023]
Abstract
Truncated or shorter forms of G protein-coupled receptors (GPCRs), originating by alternative splicing, have been considered physiologically irrelevant for a rather long time. Nevertheless, it is now recognized that alternative splicing variants of GPCRs greatly increase the total number of receptor isoforms and can regulate receptor trafficking and signalling. Furthermore, dimerization of these truncated variants with other receptors concurs to expand receptor diversity. Highly truncated variants of GPCRs, typically, are retained in the endoplasmic reticulum (ER) and by heteromerization prevent the wild-type receptor to reach the plasma membrane, exerting a dominant-negative effect on its function. This can be responsible for some pathological conditions but in some other cases, it can offer protection from a disease because the expression of the receptor, that is necessary for binding an infectious agent, is attenuated. Here, we propose a possible new mechanism of creation of truncated GPCR variants through an internal ribosome entry site (IRES), a nucleotide sequence that allows cap independent translation of proteins by recruiting the ribosome in proximity of an internal initiation codon. We suggest that an IRES, situated in the third cytoplasmic loop, could be responsible for the translation of the last two transmembrane (TM) regions of the muscarinic M2receptor. IRES driven expression of this C-terminal part of the muscarinic M2receptor could represent a novel and additional mechanism of receptor regulation.
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Müller A, Berkmann JC, Scheerer P, Biebermann H, Kleinau G. Insights into Basal Signaling Regulation, Oligomerization, and Structural Organization of the Human G-Protein Coupled Receptor 83. PLoS One 2016; 11:e0168260. [PMID: 27936173 PMCID: PMC5148169 DOI: 10.1371/journal.pone.0168260] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/29/2016] [Indexed: 12/22/2022] Open
Abstract
The murine G-protein coupled receptor 83 (mGPR83) is expressed in the hypothalamus and was previously suggested to be involved in the regulation of metabolism. The neuropeptide PEN has been recently identified as a potent GPR83 ligand. Moreover, GPR83 constitutes functionally relevant hetero-oligomers with other G-protein coupled receptors (GPCR) such as the ghrelin receptor (GHSR) or GPR171. Previous deletion studies also revealed that the long N-terminal extracellular receptor domain (eNDo) of mGPR83 may act as an intra-molecular ligand, which participates in the regulation of basal signaling activity, which is a key feature of GPCR function. Here, we investigated particular amino acids at the eNDo of human GPR83 (hGPR83) by side-directed mutagenesis to identify determinants of the internal ligand. These studies were accompanied by structure homology modeling to combine functional insights with structural information. The capacity for hetero-oligomer formation of hGPR83 with diverse family A GPCRs such as the melanocortin-4 receptor (MC4R) was also investigated, with a specific emphasis on the impact of the eNDo on oligomerization and basal signaling properties. Finally, we demonstrate that hGPR83 exhibits an unusual basal signaling for different effectors, which also supports signaling promiscuity. hGPR83 interacts with a variety of hypothalamic GPCRs such as the MC4R or GHSR. These interactions are not dependent on the ectodomain and most likely occur at interfaces constituted in the transmembrane regions. Moreover, several amino acids at the transition between the eNDo and transmembrane helix 1 were identified, where mutations lead also to biased basal signaling modulation.
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Affiliation(s)
- Anne Müller
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Julia Catherine Berkmann
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Patrick Scheerer
- Institut für Medizinische Physik und Biophysik, Group Protein X-ray Crystallography and Signal Transduction, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
- * E-mail:
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Schonnop L, Kleinau G, Herrfurth N, Volckmar AL, Cetindag C, Müller A, Peters T, Herpertz S, Antel J, Hebebrand J, Biebermann H, Hinney A. Decreased melanocortin-4 receptor function conferred by an infrequent variant at the human melanocortin receptor accessory protein 2 gene. Obesity (Silver Spring) 2016; 24:1976-82. [PMID: 27474872 DOI: 10.1002/oby.21576] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 01/17/2023]
Abstract
OBJECTIVE The melanocortin receptor accessory protein 2 (MRAP2) is relevant for weight regulation in mice and humans. This function is likely mediated by regulation of the melanocortin-4 receptor (MC4R). Functional implications of human MRAP2 mutations have not been described yet. METHODS A mutation screen was conducted in MRAP2 in 184 children and adolescents with (extreme) obesity and in 184 lean controls. Detected nonsynonymous variants were genotyped in larger independent study groups (300 people with obesity and 436 individuals with normal weight). The influence of mutant MRAP2 on MC4R signaling was analyzed in vitro. RESULTS (1) Three (two novel) nonsynonymous MRAP2 variants were detected: p.Ala137Thr, p.Gln174Arg, p.Arg125His (rs115655382), two synonymous variants, and three intronic variants. (2) The impact of MRAP2 on MC4R function was dependent on the ratio between the two co-expressed proteins. Increased MC4R signaling was detected at MRAP2/MC4R ratios of 2 + 1 and above. (3) The function of MC4R was reduced with the infrequent allele at the MRAP2 p.Gln174Arg variant. (4) The three nonsynonymous mutations were each only detected once among the 484 people with obesity and not among 620 individuals with normal weight. CONCLUSIONS This was the first study describing an effect of a MRAP2 mutation on MC4R function.
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Affiliation(s)
- Laura Schonnop
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité, Berlin, Germany
| | - Nikolas Herrfurth
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Anna-Lena Volckmar
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Cigdem Cetindag
- Institute of Experimental Pediatric Endocrinology, Charité, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology, Charité, Berlin, Germany
| | - Triinu Peters
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stephan Herpertz
- Department of Psychosomatic Medicine and Psychotherapy, LWL University Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Jochen Antel
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Johannes Hebebrand
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité, Berlin, Germany
| | - Anke Hinney
- Department of Child and Adolescent Psychiatry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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40
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Kleinau G, Müller A, Biebermann H. Oligomerization of GPCRs involved in endocrine regulation. J Mol Endocrinol 2016; 57:R59-80. [PMID: 27151573 DOI: 10.1530/jme-16-0049] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/04/2016] [Indexed: 12/27/2022]
Abstract
More than 800 different human membrane-spanning G-protein-coupled receptors (GPCRs) serve as signal transducers at biological barriers. These receptors are activated by a wide variety of ligands such as peptides, ions and hormones, and are able to activate a diverse set of intracellular signaling pathways. GPCRs are of central importance in endocrine regulation, which underpins the significance of comprehensively studying these receptors and interrelated systems. During the last decade, the capacity for multimerization of GPCRs was found to be a common and functionally relevant property. The interaction between GPCR monomers results in higher order complexes such as homomers (identical receptor subtype) or heteromers (different receptor subtypes), which may be present in a specific and dynamic monomer/oligomer equilibrium. It is widely accepted that the oligomerization of GPCRs is a mechanism for determining the fine-tuning and expansion of cellular processes by modification of ligand action, expression levels, and related signaling outcome. Accordingly, oligomerization provides exciting opportunities to optimize pharmacological treatment with respect to receptor target and tissue selectivity or for the development of diagnostic tools. On the other hand, GPCR heteromerization may be a potential reason for the undesired side effects of pharmacological interventions, faced with numerous and common mutual signaling modifications in heteromeric constellations. Finally, detailed deciphering of the physiological occurrence and relevance of specific GPCR/GPCR-ligand interactions poses a future challenge. This review will tackle the aspects of GPCR oligomerization with specific emphasis on family A GPCRs involved in endocrine regulation, whereby only a subset of these receptors will be discussed in detail.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
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Wolf Horrell EM, Boulanger MC, D’Orazio JA. Melanocortin 1 Receptor: Structure, Function, and Regulation. Front Genet 2016; 7:95. [PMID: 27303435 PMCID: PMC4885833 DOI: 10.3389/fgene.2016.00095] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/13/2016] [Indexed: 01/04/2023] Open
Abstract
The melanocortin 1 receptor (MC1R) is a melanocytic Gs protein coupled receptor that regulates skin pigmentation, UV responses, and melanoma risk. It is a highly polymorphic gene, and loss of function correlates with a fair, UV-sensitive, and melanoma-prone phenotype due to defective epidermal melanization and sub-optimal DNA repair. MC1R signaling, achieved through adenylyl cyclase activation and generation of the second messenger cAMP, is hormonally controlled by the positive agonist melanocortin, the negative agonist agouti signaling protein, and the neutral antagonist β-defensin 3. Activation of cAMP signaling up-regulates melanin production and deposition in the epidermis which functions to limit UV penetration into the skin and enhances nucleotide excision repair (NER), the genomic stability pathway responsible for clearing UV photolesions from DNA to avoid mutagenesis. Herein we review MC1R structure and function and summarize our laboratory's findings on the molecular mechanisms by which MC1R signaling impacts NER.
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Affiliation(s)
- Erin M. Wolf Horrell
- Department of Physiology, University of Kentucky College of MedicineLexington, KY, USA
| | - Mary C. Boulanger
- Markey Cancer Center, University of Kentucky College of MedicineLexington, KY, USA
| | - John A. D’Orazio
- Department of Physiology, University of Kentucky College of MedicineLexington, KY, USA
- Markey Cancer Center, University of Kentucky College of MedicineLexington, KY, USA
- Departments of Pediatrics, Toxicology and Cancer Biology, Physiology, and Pharmacology and Nutritional Sciences, University of Kentucky College of MedicineLexington, KY, USA
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Breit A, Wicht K, Boekhoff I, Glas E, Lauffer L, Mückter H, Gudermann T. Glucose Enhances Basal or Melanocortin-Induced cAMP-Response Element Activity in Hypothalamic Cells. Mol Endocrinol 2016; 30:748-62. [PMID: 27144291 DOI: 10.1210/me.2016-1001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Melanocyte-stimulating hormone (MSH)-induced activation of the cAMP-response element (CRE) via the CRE-binding protein in hypothalamic cells promotes expression of TRH and thereby restricts food intake and increases energy expenditure. Glucose also induces central anorexigenic effects by acting on hypothalamic neurons, but the underlying mechanisms are not completely understood. It has been proposed that glucose activates the CRE-binding protein-regulated transcriptional coactivator 2 (CRTC-2) in hypothalamic neurons by inhibition of AMP-activated protein kinases (AMPKs), but whether glucose directly affects hypothalamic CRE activity has not yet been shown. Hence, we dissected effects of glucose on basal and MSH-induced CRE activation in terms of kinetics, affinity, and desensitization in murine, hypothalamic mHypoA-2/10-CRE cells that stably express a CRE-dependent reporter gene construct. Physiologically relevant increases in extracellular glucose enhanced basal or MSH-induced CRE-dependent gene transcription, whereas prolonged elevated glucose concentrations reduced the sensitivity of mHypoA-2/10-CRE cells towards glucose. Glucose also induced CRCT-2 translocation into the nucleus and the AMPK activator metformin decreased basal and glucose-induced CRE activity, suggesting a role for AMPK/CRTC-2 in glucose-induced CRE activation. Accordingly, small interfering RNA-induced down-regulation of CRTC-2 expression decreased glucose-induced CRE-dependent reporter activation. Of note, glucose also induced expression of TRH, suggesting that glucose might affect the hypothalamic-pituitary-thyroid axis via the regulation of hypothalamic CRE activity. These findings significantly advance our knowledge about the impact of glucose on hypothalamic signaling and suggest that TRH release might account for the central anorexigenic effects of glucose and could represent a new molecular link between hyperglycaemia and thyroid dysfunction.
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Affiliation(s)
- Andreas Breit
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
| | - Kristina Wicht
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
| | - Ingrid Boekhoff
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
| | - Evi Glas
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
| | - Lisa Lauffer
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
| | - Harald Mückter
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
| | - Thomas Gudermann
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
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Lensing CJ, Freeman KT, Schnell SM, Adank DN, Speth RC, Haskell-Luevano C. An in Vitro and in Vivo Investigation of Bivalent Ligands That Display Preferential Binding and Functional Activity for Different Melanocortin Receptor Homodimers. J Med Chem 2016; 59:3112-28. [PMID: 26959173 DOI: 10.1021/acs.jmedchem.5b01894] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Pharmacological probes for the melanocortin receptors have been utilized for studying various disease states including cancer, sexual function disorders, Alzheimer's disease, social disorders, cachexia, and obesity. This study focused on the design and synthesis of bivalent ligands to target melanocortin receptor homodimers. Lead ligands increased binding affinity by 14- to 25-fold and increased cAMP signaling potency by 3- to 5-fold compared to their monovalent counterparts. Unexpectedly, different bivalent ligands showed preferences for particular melanocortin receptor subtypes depending on the linker that connected the binding scaffolds, suggesting structural differences between the various dimer subtypes. Homobivalent compound 12 possessed a functional profile that was unique from its monovalent counterpart providing evidence of the discrete effects of bivalent ligands. Lead compound 7 significantly decreased feeding in mice after intracerebroventricular administration. To the best of our knowledge, this is the first report of a melanocortin bivalent ligand's in vivo physiological effects.
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Affiliation(s)
- Cody J Lensing
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Katie T Freeman
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Sathya M Schnell
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Danielle N Adank
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Robert C Speth
- College of Pharmacy, Nova Southeastern University , Fort Lauderdale, Florida 33328-2018, United States.,Department of Pharmacology and Physiology, Georgetown University , Washington, D.C. 20057, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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Mutations in Melanocortin-3 Receptor Gene and Human Obesity. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 140:97-129. [DOI: 10.1016/bs.pmbts.2016.01.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Stoy H, Gurevich VV. How genetic errors in GPCRs affect their function: Possible therapeutic strategies. Genes Dis 2015; 2:108-132. [PMID: 26229975 PMCID: PMC4516391 DOI: 10.1016/j.gendis.2015.02.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 02/07/2015] [Indexed: 01/14/2023] Open
Abstract
Activating and inactivating mutations in numerous human G protein-coupled receptors (GPCRs) are associated with a wide range of disease phenotypes. Here we use several class A GPCRs with a particularly large set of identified disease-associated mutations, many of which were biochemically characterized, along with known GPCR structures and current models of GPCR activation, to understand the molecular mechanisms yielding pathological phenotypes. Based on this mechanistic understanding we also propose different therapeutic approaches, both conventional, using small molecule ligands, and novel, involving gene therapy.
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Yun JH, Kim M, Kim K, Lee D, Jung Y, Oh D, Ko YJ, Cho AE, Cho HS, Lee W. Solution structure of the transmembrane 2 domain of the human melanocortin-4 receptor in sodium dodecyl sulfate (SDS) micelles and the functional implication of the D90N mutant. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1294-302. [PMID: 25753114 DOI: 10.1016/j.bbamem.2015.02.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 02/03/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
The melanocortin receptors (MCRs) are members of the G protein-coupled receptor (GPCR) 1 superfamily with seven transmembrane (TM) domains. Among them, the melanocortin-4 receptor (MC4R) subtype has been highlighted recently by genetic studies in obese humans. In particular, in a patient with severe early-onset obesity, a novel heterozygous mutation in the MC4R gene was found in an exchange of Asp to Asn in the 90th amino acid residue located in the TM 2 domain (MC4RD90N). Mutations in the MC4R gene are the most frequent monogenic causes of severe obesity and are described as heterozygous with loss of function. We determine solution structures of the TM 2 domain of MC4R (MC4RTM2) and compared secondary structure of Asp90 mutant (MC4RTM2-D90N) in a micelle environment by nuclear magnetic resonance (NMR) spectroscopy. NMR structure shows that MC4RTM2 forms a long α-helix with a kink at Gly98. Interestingly, the structure of MC4RTM2-D90N is similar to that of MC4RTM2 based on data from CD and NMR spectrum. However, the thermal stability and homogeneity of MC4RD90N is quite different from those of MC4R. The structure from molecular modeling suggests that Asp90(2.50) plays a key role in allosteric sodium ion binding. Our data suggest that the sodium ion interaction of Asp90(2.50) in the allosteric pocket of MC4R is essential to its function, explaining the loss of function of the MC4RD90N mutant.
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Affiliation(s)
- Ji-Hye Yun
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Minsup Kim
- Department of Bioinformatics, Korea University, Sejong 136-701, Republic of Korea
| | - Kuglae Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Dongju Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Youngjin Jung
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Daeseok Oh
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Yoon-Joo Ko
- National Center for Inter-University Research Facilities, Seoul National University, Seoul 151-747, Republic of Korea
| | - Art E Cho
- Department of Bioinformatics, Korea University, Sejong 136-701, Republic of Korea
| | - Hyun-Soo Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Weontae Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea.
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He S, Tao YX. Defect in MAPK signaling as a cause for monogenic obesity caused by inactivating mutations in the melanocortin-4 receptor gene. Int J Biol Sci 2014; 10:1128-37. [PMID: 25332687 PMCID: PMC4202029 DOI: 10.7150/ijbs.10359] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 09/15/2014] [Indexed: 12/22/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) is a Family A G protein-coupled receptor that plays an essential role in regulating energy homeostasis, including both energy intake and expenditure. Mutations leading to a reduced MC4R function confer a major gene effect for obesity. More than 170 distinct mutations have been identified in humans. In addition to the conventional Gs-stimulated cAMP pathway, the MC4R also activates MAPKs, especially ERK1/2. We also showed there is biased signaling in the two signaling pathways, with inverse agonists in the Gs-cAMP pathway acting as agonists for the ERK1/2 pathway. In the current study, we sought to determine whether defects in basal or agonist-induced ERK1/2 activation in MC4R mutants might potentially contribute to obesity pathogenesis in patients carrying these mutations. The constitutive and ligand-stimulated ERK1/2 activation were measured in wild type and 73 naturally occurring MC4R mutations. We showed that nineteen mutants had significantly decreased basal pERK1/2 level, and five Class V variants (where no functional defects have been identified previously), C40R, V50M, T112M, A154D and S295P, had impaired ligand-stimulated ERK1/2 activation. Our studies demonstrated for the first time that decreased basal or ligand-stimulated ERK1/2 signaling might contribute to obesity pathogenesis caused by mutations in the MC4R gene. We also observed biased signaling in 25 naturally occurring mutations in the Gs-cAMP and ERK1/2 pathways.
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Affiliation(s)
- Shan He
- 1. Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519, USA. ; 2. Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China
| | - Ya-Xiong Tao
- 1. Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519, USA
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Boughton CK, Murphy KG. Can neuropeptides treat obesity? A review of neuropeptides and their potential role in the treatment of obesity. Br J Pharmacol 2014; 170:1333-48. [PMID: 23121386 DOI: 10.1111/bph.12037] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/17/2012] [Accepted: 10/17/2012] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Obesity is a major worldwide public health issue. The physiological systems that regulate body weight are thus of great interest as targets for anti-obesity agents. Peptidergic systems are critical to the regulation of energy homeostasis by key regions in the hypothalamus and brainstem. A number of neuropeptide systems have therefore been investigated as potential treatments for obesity. Blocking orexigenic peptide signals such as neuropeptide Y, melanin-concentrating hormone, orexins, relaxin-3 and galanin-like peptide or stimulating anorectic signalling pathways used by peptides such as the melanocortins, ciliary neurotrophic factor and brain-derived neurotrophic factor, are approaches that have shown some promise, but which have also highlighted possible concerns. Manipulation of central peptidergic systems poses a number of therapeutic problems, including brain access and side effects. Given that the homeostatic defence of body weight may limit the effectiveness of any single-target therapy developed, a combination therapy approach may offer the best hope for the effective prevention and treatment of obesity. LINKED ARTICLES This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.
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Affiliation(s)
- C K Boughton
- Section of Investigative Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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Tao YX, Conn PM. Chaperoning G protein-coupled receptors: from cell biology to therapeutics. Endocr Rev 2014; 35:602-47. [PMID: 24661201 PMCID: PMC4105357 DOI: 10.1210/er.2013-1121] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 03/14/2014] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) are membrane proteins that traverse the plasma membrane seven times (hence, are also called 7TM receptors). The polytopic structure of GPCRs makes the folding of GPCRs difficult and complex. Indeed, many wild-type GPCRs are not folded optimally, and defects in folding are the most common cause of genetic diseases due to GPCR mutations. Both general and receptor-specific molecular chaperones aid the folding of GPCRs. Chemical chaperones have been shown to be able to correct the misfolding in mutant GPCRs, proving to be important tools for studying the structure-function relationship of GPCRs. However, their potential therapeutic value is very limited. Pharmacological chaperones (pharmacoperones) are potentially important novel therapeutics for treating genetic diseases caused by mutations in GPCR genes that resulted in misfolded mutant proteins. Pharmacoperones also increase cell surface expression of wild-type GPCRs; therefore, they could be used to treat diseases that do not harbor mutations in GPCRs. Recent studies have shown that indeed pharmacoperones work in both experimental animals and patients. High-throughput assays have been developed to identify new pharmacoperones that could be used as therapeutics for a number of endocrine and other genetic diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology (Y.-X.T.), College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519; and Departments of Internal Medicine and Cell Biology (P.M.C.), Texas Tech University Health Science Center, Lubbock, Texas 79430-6252
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50
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Huang H, Tao YX. A small molecule agonist THIQ as a novel pharmacoperone for intracellularly retained melanocortin-4 receptor mutants. Int J Biol Sci 2014; 10:817-24. [PMID: 25076858 PMCID: PMC4115193 DOI: 10.7150/ijbs.9625] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/01/2014] [Indexed: 01/04/2023] Open
Abstract
Although mutations in the melanocortin-4 receptor (MC4R) gene cause severe early-onset obesity, we still do not have effective approaches to correct the defects of these mutations. Several antagonists have been identified as pharmacoperones of the MC4R whereas no agonist of the MC4R has been reported. In the present study, we investigated the effect of a small molecule agonist of the MC4R, THIQ, on the cell surface expression and signaling of ten intracellularly retained MC4R mutants using different cell lines. We showed that THIQ increased the cell surface expression of three mutants (N62S, C84R, and C271Y) and two of them (N62S and C84R) had increased signaling in HEK293 cells. Interestingly, THIQ increased the signaling of two other mutants (P78L and P260Q) without increasing their cell surface expression in HEK293 cells. In neuronal cells, THIQ exhibited a more potent effect, correcting the cell surface expression and signaling of seven mutants (N62S, I69R, P78L, C84R, W174C, P260Q, and C271Y). Other mutants were not rescued by THIQ. We also showed that THIQ did not rescue MC4R mutants defective in ligand binding or signaling or one intracellularly retained mutant of the melanocortin-3 receptor. In summary, we demonstrated that a small molecule agonist acted as a pharmacoperone of the MC4R rescuing the cell surface expression and signaling of some intracellularly retained MC4R mutants.
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Affiliation(s)
- Hui Huang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
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