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Scharf MM, Humphrys LJ, Berndt S, Di Pizio A, Lehmann J, Liebscher I, Nicoli A, Niv MY, Peri L, Schihada H, Schulte G. The dark sides of the GPCR tree - research progress on understudied GPCRs. Br J Pharmacol 2024. [PMID: 38339984 DOI: 10.1111/bph.16325] [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: 08/25/2023] [Revised: 11/24/2023] [Accepted: 01/08/2024] [Indexed: 02/12/2024] Open
Abstract
A large portion of the human GPCRome is still in the dark and understudied, consisting even of entire subfamilies of GPCRs such as odorant receptors, class A and C orphans, adhesion GPCRs, Frizzleds and taste receptors. However, it is undeniable that these GPCRs bring an untapped therapeutic potential that should be explored further. Open questions on these GPCRs span diverse topics such as deorphanisation, the development of tool compounds and tools for studying these GPCRs, as well as understanding basic signalling mechanisms. This review gives an overview of the current state of knowledge for each of the diverse subfamilies of understudied receptors regarding their physiological relevance, molecular mechanisms, endogenous ligands and pharmacological tools. Furthermore, it identifies some of the largest knowledge gaps that should be addressed in the foreseeable future and lists some general strategies that might be helpful in this process.
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Affiliation(s)
- Magdalena M Scharf
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Stockholm, Sweden
| | - Laura J Humphrys
- Institute of Pharmacy, University of Regensburg, Regensburg, Germany
| | - Sandra Berndt
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Antonella Di Pizio
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
- Chemoinformatics and Protein Modelling, Department of Molecular Life Science, School of Life Science, Technical University of Munich, Freising, Germany
| | - Juliane Lehmann
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Alessandro Nicoli
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
- Chemoinformatics and Protein Modelling, Department of Molecular Life Science, School of Life Science, Technical University of Munich, Freising, Germany
| | - Masha Y Niv
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Lior Peri
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Hannes Schihada
- Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Gunnar Schulte
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Stockholm, Sweden
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Urwyler-Rösselet C, Tanghe G, Devos M, Hulpiau P, Saeys Y, Declercq W. Functions of the RIP kinase family members in the skin. Cell Mol Life Sci 2023; 80:285. [PMID: 37688617 PMCID: PMC10492769 DOI: 10.1007/s00018-023-04917-2] [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: 05/02/2022] [Revised: 07/08/2023] [Accepted: 08/08/2023] [Indexed: 09/11/2023]
Abstract
The receptor interacting protein kinases (RIPK) are a family of serine/threonine kinases that are involved in the integration of various stress signals. In response to several extracellular and/or intracellular stimuli, RIP kinases engage signaling cascades leading to the activation of NF-κB and mitogen-activated protein kinases, cell death, inflammation, differentiation and Wnt signaling and can have kinase-dependent and kinase-independent functions. Although it was previously suggested that seven RIPKs are part of the RIPK family, phylogenetic analysis indicates that there are only five genuine RIPKs. RIPK1 and RIPK3 are mainly involved in controlling and executing necroptosis in keratinocytes, while RIPK4 controls proliferation and differentiation of keratinocytes and thereby can act as a tumor suppressor in skin. Therefore, in this review we summarize and discuss the functions of RIPKs in skin homeostasis as well as the signaling pathways involved.
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Affiliation(s)
- Corinne Urwyler-Rösselet
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biology, Institute of Molecular Health Sciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Giel Tanghe
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- VIB Center for Inflammation Research, Ghent, Belgium
| | - Michael Devos
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- VIB Center for Inflammation Research, Ghent, Belgium
| | - Paco Hulpiau
- VIB Center for Inflammation Research, Ghent, Belgium
- Howest University of Applied Sciences, Brugge, Belgium
| | - Yvan Saeys
- VIB Center for Inflammation Research, Ghent, Belgium
- Department of Applied Mathematics and Computer Science, Ghent University, Ghent, Belgium
| | - Wim Declercq
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
- VIB Center for Inflammation Research, Ghent, Belgium.
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3
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Torrecillas-Baena B, Camacho-Cardenosa M, Quesada-Gómez JM, Moreno-Moreno P, Dorado G, Gálvez-Moreno MÁ, Casado-Díaz A. Non-Specific Inhibition of Dipeptidyl Peptidases 8/9 by Dipeptidyl Peptidase 4 Inhibitors Negatively Affects Mesenchymal Stem Cell Differentiation. J Clin Med 2023; 12:4632. [PMID: 37510747 PMCID: PMC10380885 DOI: 10.3390/jcm12144632] [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: 05/26/2023] [Revised: 07/03/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
DPP4 may play a relevant role in MSC differentiation into osteoblasts or adipocytes. Dipeptidyl peptidase 4 (DPP4) inhibitors (DPP4i), such as sitagliptin and vildagliptin, are used as antidiabetic drugs. However, vildagliptin is not a specific DPP4i and also inhibits DPP8/9, which is involved in energy metabolism and immune regulation. The aim of this study is to evaluate how sitagliptin, vildagliptin or 1G244 (a DPP8/9 specific inhibitor) may influence cell viability, as well as osteogenic and adipogenic differentiation in human mesenchymal stem cells (MSC). Viability, apoptosis, osteoblastogenesis and adipogenesis markers, as well as protein synthesis of β-catenin, were studied in MSC cultures induced to differentiate into osteoblasts or adipocytes in the presence or absence of sitagliptin, vildagliptin or 1G244. The two tested DPP4i did not affect MSC viability, but 1G244 significantly decreased it in MSC and osteoblast-induced cells. Additionally, 1G244 and vildagliptin inhibited osteogenesis and adipogenesis, unlike sitagliptin. Therefore, inhibition of DPP4 did not affect MSC viability and differentiation, whereas inhibition of DPP8/9 negatively affected MSC. To the best of our knowledge, these results show for the first time that DPP8/9 have an important role in the viability and differentiation of human MSC. This data can be considered for human clinical use of drugs affecting DPP8/9 activity.
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Affiliation(s)
- Bárbara Torrecillas-Baena
- Unidad de Gestión Clínica de Endocrinología y Nutrición-GC17, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
- CIBER de Fragilidad y Envejecimiento Saludable (CIBERFES), 14004 Córdoba, Spain
| | - Marta Camacho-Cardenosa
- Unidad de Gestión Clínica de Endocrinología y Nutrición-GC17, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
| | - José Manuel Quesada-Gómez
- Unidad de Gestión Clínica de Endocrinología y Nutrición-GC17, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
| | - Paloma Moreno-Moreno
- Unidad de Gestión Clínica de Endocrinología y Nutrición-GC17, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
| | - Gabriel Dorado
- CIBER de Fragilidad y Envejecimiento Saludable (CIBERFES), 14004 Córdoba, Spain
- Departamento Bioquímica y Biología Molecular, Campus Rabanales C6-1-E17, Campus de Excelencia Internacional Agroalimentario (ceiA3), Universidad de Córdoba, 14071 Córdoba, Spain
| | - María Ángeles Gálvez-Moreno
- Unidad de Gestión Clínica de Endocrinología y Nutrición-GC17, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
| | - Antonio Casado-Díaz
- Unidad de Gestión Clínica de Endocrinología y Nutrición-GC17, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
- CIBER de Fragilidad y Envejecimiento Saludable (CIBERFES), 14004 Córdoba, Spain
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Lotfollahzadeh S, Xia C, Amraei R, Hua N, Kandror KV, Farmer SR, Wei W, Costello CE, Chitalia V, Rahimi N. Inactivation of Minar2 in mice hyperactivates mTOR signaling and results in obesity. Mol Metab 2023; 73:101744. [PMID: 37245847 PMCID: PMC10267597 DOI: 10.1016/j.molmet.2023.101744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 05/30/2023] Open
Abstract
OBJECTIVE Obesity is a complex disorder and is linked to chronic diseases such as type 2 diabetes. Major intrinsically disordered NOTCH2-associated receptor2 (MINAR2) is an understudied protein with an unknown role in obesity and metabolism. The purpose of this study was to determine the impact of Minar2 on adipose tissues and obesity. METHOD We generated Minar2 knockout (KO) mice and used various molecular, proteomic, biochemical, histopathology, and cell culture studies to determine the pathophysiological role of Minar2 in adipocytes. RESULTS We demonstrated that the inactivation of Minar2 results in increased body fat with hypertrophic adipocytes. Minar2 KO mice on a high-fat diet develop obesity and impaired glucose tolerance and metabolism. Mechanistically, Minar2 interacts with Raptor, a specific and essential component of mammalian TOR complex 1 (mTORC1) and inhibits mTOR activation. mTOR is hyperactivated in the adipocytes deficient for Minar2 and over-expression of Minar2 in HEK-293 cells inhibited mTOR activation and phosphorylation of mTORC1 substrates, including S6 kinase, and 4E-BP1. CONCLUSION Our findings identified Minar2 as a novel physiological negative regulator of mTORC1 with a key role in obesity and metabolic disorders. Impaired expression or activation of MINAR2 could lead to obesity and obesity-associated diseases.
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Affiliation(s)
- Saran Lotfollahzadeh
- Renal Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Chaoshuang Xia
- Center for Biomedical Mass Spectrometry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Razie Amraei
- Department of Pathology and Laboratory Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Ning Hua
- Biomed Research Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Konstantin V Kandror
- Department of Biochemistry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Stephen R Farmer
- Department of Biochemistry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Catherine E Costello
- Center for Biomedical Mass Spectrometry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA; Department of Biochemistry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
| | - Vipul Chitalia
- Renal Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA; Veterans Affairs Boston Healthcare System, Boston, MA, USA; Institute of Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Nader Rahimi
- Department of Pathology and Laboratory Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
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Shi L, Zhou L, Han M, Zhang Y, Zhang Y, Yuan XX, Lu HP, Wang Y, Yang XL, Liu C, Wang J, Liang P, Liu SA, Liu XJ, Cheng J, Lin SM. Calcitriol attenuates liver fibrosis through hepatitis C virus nonstructural protein 3-transactivated protein 1-mediated TGF β1/Smad3 and NF-κB signaling pathways. World J Gastroenterol 2023; 29:2798-2817. [PMID: 37274069 PMCID: PMC10237113 DOI: 10.3748/wjg.v29.i18.2798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/08/2023] [Accepted: 04/10/2023] [Indexed: 05/11/2023] Open
Abstract
BACKGROUND Hepatic fibrosis is a serious condition, and the development of hepatic fibrosis can lead to a series of complications. However, the pathogenesis of hepatic fibrosis remains unclear, and effective therapy options are still lacking. Our group identified hepatitis C virus nonstructural protein 3-transactivated protein 1 (NS3TP1) by suppressive subtractive hybridization and bioinformatics analysis, but its role in diseases including hepatic fibrosis remains undefined. Therefore, additional studies on the function of NS3TP1 in hepatic fibrosis are urgently needed to provide new targets for treatment.
AIM To elucidate the mechanism of NS3TP1 in hepatic fibrosis and the regulatory effects of calcitriol on NS3TP1.
METHODS Twenty-four male C57BL/6 mice were randomized and separated into three groups, comprising the normal, fibrosis, and calcitriol treatment groups, and liver fibrosis was modeled by carbon tetrachloride (CCl4). To evaluate the level of hepatic fibrosis in every group, serological and pathological examinations of the liver were conducted. TGF-β1 was administered to boost the in vitro cultivation of LX-2 cells. NS3TP1, α-smooth muscle actin (α-SMA), collagen I, and collagen III in every group were examined using a Western blot and real-time quantitative polymerase chain reaction. The activity of the transforming growth factor beta 1 (TGFβ1)/Smad3 and NF-κB signaling pathways in each group of cells transfected with pcDNA-NS3TP1 or siRNA-NS3TP1 was detected. The statistical analysis of the data was performed using the Student’s t test.
RESULTS NS3TP1 promoted the activation, proliferation, and differentiation of hepatic stellate cells (HSCs) and enhanced hepatic fibrosis via the TGFβ1/Smad3 and NF-κB signaling pathways, as evidenced by the presence of α-SMA, collagen I, collagen III, p-smad3, and p-p65 in LX-2 cells, which were upregulated after NS3TP1 overexpression and downregulated after NS3TP1 interference. The proliferation of HSCs was lowered after NS3TP1 interference and elevated after NS3TP1 overexpression, as shown by the luciferase assay. NS3TP1 inhibited the apoptosis of HSCs. Moreover, both Smad3 and p65 could bind to NS3TP1, and p65 increased the promoter activity of NS3TP1, while NS3TP1 increased the promoter activity of TGFβ1 receptor I, as indicated by coimmunoprecipitation and luciferase assay results. Both in vivo and in vitro, treatment with calcitriol dramatically reduced the expression of NS3TP1. Calcitriol therapy-controlled HSCs activation, proliferation, and differentiation and substantially suppressed CCl4-induced hepatic fibrosis in mice. Furthermore, calcitriol modulated the activities of the above signaling pathways via downregulation of NS3TP1.
CONCLUSION Our results suggest that calcitriol may be employed as an adjuvant therapy for hepatic fibrosis and that NS3TP1 is a unique, prospective therapeutic target in hepatic fibrosis.
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Affiliation(s)
- Liu Shi
- Department of Infectious Disease Medicine, The First Hospital Affiliated to Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
| | - Li Zhou
- China-Japan Friendship Hospital, Department of Infectious Disease China-Japan Friendship Hospital, Beijing 100029, China
| | - Ming Han
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Yu Zhang
- The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Yang Zhang
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Xiao-Xue Yuan
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Hong-Ping Lu
- Institute of Liver Diseases, Beijing Pan-Asia Tongze Institute of Biomedicine Co., Ltd, Beijing 100015, China
| | - Yun Wang
- The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Xue-Liang Yang
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
| | - Chen Liu
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Jun Wang
- Beijing Key Laboratory of Emerging Infectious Diseases, Peking University Ditan Teaching Hospital, Beijing 100015, China
| | - Pu Liang
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Shun-Ai Liu
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Xiao-Jing Liu
- Department of Infectious Disease Medicine, The First Hospital Affiliated to Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
| | - Jun Cheng
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Shu-Mei Lin
- Department of Infectious Disease Medicine, The First Hospital Affiliated to Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
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Leggieri A, García-González J, Torres-Perez JV, Havelange W, Hosseinian S, Mech AM, Keatinge M, Busch-Nentwich EM, Brennan CH. Ankk1 Loss of Function Disrupts Dopaminergic Pathways in Zebrafish. Front Neurosci 2022; 16:794653. [PMID: 35210987 PMCID: PMC8861280 DOI: 10.3389/fnins.2022.794653] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
Ankyrin repeat and kinase domain containing 1 (ANKK1) is a member of the receptor-interacting protein serine/threonine kinase family, known to be involved in cell proliferation, differentiation and activation of transcription factors. Genetic variation within the ANKK1 locus is suggested to play a role in vulnerability to addictions. However, ANKK1 mechanism of action is still poorly understood. It has been suggested that ANKK1 may affect the development and/or functioning of dopaminergic pathways. To test this hypothesis, we generated a CRISPR-Cas9 loss of function ankk1 zebrafish line causing a 27 bp insertion that disrupts the ankk1 sequence introducing an early stop codon. We found that ankk1 transcript levels were significantly lower in ankk1 mutant (ankk127ins) fish compared to their wild type (ankk1+/+) siblings. In ankk1+/+ adult zebrafish brain, ankk1 protein was detected in isocortex, hippocampus, basolateral amygdala, mesencephalon, and cerebellum, resembling the mammalian distribution pattern. In contrast, ankk1 protein was reduced in the brain of ankk127ins/27ins fish. Quantitative polymerase chain reaction analysis revealed an increase in expression of drd2b mRNA in ankk127ins at both larval and adult stages. In ankk1+/+ adult zebrafish brain, drd2 protein was detected in cerebral cortex, cerebellum, hippocampus, and caudate homolog regions, resembling the pattern in humans. In contrast, drd2 expression was reduced in cortical regions of ankk127ins/27ins being predominantly found in the hindbrain. No differences in the number of cell bodies or axonal projections detected by anti-tyrosine hydroxylase immunostaining on 3 days post fertilization (dpf) larvae were found. Behavioral analysis revealed altered sensitivity to effects of both amisulpride and apomorphine on locomotion and startle habituation, consistent with a broad loss of both pre and post synaptic receptors. Ankk127ins mutants showed reduced sensitivity to the effect of the selective dopamine receptor antagonist amisulpride on locomotor responses to acoustic startle and were differentially sensitive to the effects of the non-selective dopamine agonist apomorphine on both locomotion and habituation. Taken together, our findings strengthen the hypothesis of a functional relationship between ANKK1 and DRD2, supporting a role for ANKK1 in the maintenance and/or functioning of dopaminergic pathways. Further work is needed to disentangle ANKK1’s role at different developmental stages.
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Affiliation(s)
- Adele Leggieri
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Judit García-González
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jose V. Torres-Perez
- Department of Brain Sciences, UK Dementia Research Institute, Imperial College London, London, United Kingdom
| | - William Havelange
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Saeedeh Hosseinian
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Aleksandra M. Mech
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Marcus Keatinge
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Elisabeth M. Busch-Nentwich
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Caroline H. Brennan
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
- *Correspondence: Caroline H. Brennan,
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Powell DR, Doree DD, DaCosta CM, Platt KA, Brommage R, Buhring L, Revelli JP, Shadoan MK. Mice Lacking Gpr75 are Hypophagic and Thin. Diabetes Metab Syndr Obes 2022; 15:45-58. [PMID: 35023939 PMCID: PMC8743382 DOI: 10.2147/dmso.s342799] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/15/2021] [Indexed: 01/31/2023] Open
Abstract
PURPOSE Humans with haploinsufficiency of GPR75, an orphan GPCR, are thin. Gpr75 knockout (KO) mice are also thin with improved glucose homeostasis. We wanted to confirm these findings in Gpr75 KO mice and determine whether decreased energy intake and/or increased energy expenditure contributed to the thin phenotype. METHODS Gpr75 KO mice were generated by homologous recombination. All studies compared female and male Gpr75 KO mice to their wild type (WT) littermates. Body composition was measured by DXA and QMR technologies. Glucose homeostasis was evaluated by measuring glucose and insulin levels during oral glucose tolerance tests (OGTTs). Food intake was measured in group-housed mice. In singly housed mice, energy expenditure was measured in Oxymax indirect calorimetry chambers, and locomotor activity was measured in Oxymax and Photobeam Activity System chambers. RESULTS In all 12 cohorts of adult female or male mice, Gpr75 KO mice had less body fat; pooled data showed that, compared to WT littermates (n = 103), Gpr75 KO mice (n = 118) had 49% less body fat and 4% less LBM (P < 0.001 for each). KO mice also had 8% less body fat at weaning (P < 0.05), and during the month after weaning as the thin phenotype became more exaggerated, Gpr75 KO mice ate significantly less than, but had energy expenditure and activity levels comparable to, their WT littermates. During OGTTs, Gpr75 KO mice showed improved glucose tolerance (glucose AUC 23% lower in females, P < 0.05, and 26% lower in males, P < 0.001), accompanied by significantly decreased insulin levels and significantly increased insulin sensitivity indices. CONCLUSION Gpr75 KO mice are thin at weaning, are hypophagic as the thin phenotype becomes more exaggerated, and exhibit improved glucose tolerance and insulin sensitivity as healthy-appearing adults. These results suggest that inhibiting GPR75 in obese humans may safely decrease energy intake and body fat while improving glucose tolerance and insulin sensitivity.
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Affiliation(s)
- David R Powell
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Correspondence: David R Powell Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc., 2445 Technology Forest Boulevard, The Woodlands, TX, 77381, USATel +1 713 249 3972Fax +1 281 863 8115 Email
| | - Deon D Doree
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Christopher M DaCosta
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Kenneth A Platt
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc., The Woodlands, TX, USA
| | - Robert Brommage
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Lindsey Buhring
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Jean-Pierre Revelli
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Melanie K Shadoan
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
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