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Yoo YM, Joo SS. Serotonin Influences Insulin Secretion in Rat Insulinoma INS-1E Cells. Int J Mol Sci 2024; 25:6828. [PMID: 38999937 PMCID: PMC11241493 DOI: 10.3390/ijms25136828] [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: 05/09/2024] [Revised: 06/15/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024] Open
Abstract
Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine that plays a critical role in insulin secretion, energy metabolism, and mitochondrial biogenesis. However, the action of serotonin in insulin production and secretion by pancreatic β cells has not yet been elucidated. Here, we investigated how exogenous nanomolar serotonin concentrations regulate insulin synthesis and secretion in rat insulinoma INS-1E cells. Nanomolar serotonin concentrations (10 and 50 nM) significantly increased insulin protein expression above the constant levels in untreated control cells and decreased insulin protein levels in the media. The reductions in insulin protein levels in the media may be associated with ubiquitin-mediated protein degradation. The levels of membrane vesicle trafficking-related proteins including Rab5, Rab3A, syntaxin6, clathrin, and EEA1 proteins were significantly decreased by serotonin treatment compared to the untreated control cells, whereas the expressions of Rab27A, GOPC, and p-caveolin-1 proteins were significantly reduced by serotonin treatment. In this condition, serotonin receptors, Gαq-coupled 5-HT2b receptor (Htr2b), and ligand-gated ion channel receptor Htr3a were significantly decreased by serotonin treatment. To confirm the serotonylation of Rab3A and Rab27A during insulin secretion, we investigated the protein levels of Rab3A and Rab27A, in which transglutaminase 2 (TGase2) serotonylated Rab3A but not Rab27A. The increases in ERK phosphorylation levels were consistent with increases in the expression of p-Akt. Also, the expression level of the Bcl-2 protein was significantly increased by 50 and 100 nM serotonin treatment compared to the untreated control cells, whereas the levels of Cu/Zn-SOD and Mn-SOD proteins decreased. These results indicate that nanomolar serotonin treatment regulates the insulin protein level but decreases this level in media through membrane vesicle trafficking-related proteins (Rab5, Rab3A, syntaxin6, clathrin, and EEA1), the Akt/ERK pathway, and Htr2b/Htr3a in INS-1E cells.
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Affiliation(s)
- Yeong-Min Yoo
- East Coast Life Sciences Institute, College of Life Science, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
- Department of Marine Bioscience, College of Life Science, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
| | - Seong Soo Joo
- Department of Marine Bioscience, College of Life Science, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
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2
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Kung ML, Cheng SM, Wang YH, Cheng KP, Li YL, Hsiao YT, Tan BCM, Chen YW. Deficiency of ADAR2 ameliorates metabolic-associated fatty liver disease via AMPK signaling pathways in obese mice. Commun Biol 2024; 7:594. [PMID: 38760406 PMCID: PMC11101631 DOI: 10.1038/s42003-024-06215-4] [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: 10/15/2023] [Accepted: 04/18/2024] [Indexed: 05/19/2024] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a chronic disease caused by hepatic steatosis. Adenosine deaminases acting on RNA (ADARs) catalyze adenosine to inosine RNA editing. However, the functional role of ADAR2 in NAFLD is unclear. ADAR2+/+/GluR-BR/R mice (wild type, WT) and ADAR2-/-/GluR-BR/R mice (ADAR2 KO) mice are fed with standard chow or high-fat diet (HFD) for 12 weeks. ADAR2 KO mice exhibit protection against HFD-induced glucose intolerance, insulin resistance, and dyslipidemia. Moreover, ADAR2 KO mice display reduced liver lipid droplets in concert with decreased hepatic TG content, improved hepatic insulin signaling, better pyruvate tolerance, and increased glycogen synthesis. Mechanistically, ADAR2 KO effectively mitigates excessive lipid production via AMPK/Sirt1 pathway. ADAR2 KO inhibits hepatic gluconeogenesis via the AMPK/CREB pathway and promotes glycogen synthesis by activating the AMPK/GSK3β pathway. These results provide evidence that ADAR2 KO protects against NAFLD progression through the activation of AMPK signaling pathways.
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Affiliation(s)
- Mei-Lang Kung
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Siao Muk Cheng
- National Institute of Cancer Research, National Health Research Institutes (NHRI), Tainan, Taiwan
| | - Yun-Han Wang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kai-Pi Cheng
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Lin Li
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Tsen Hsiao
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Bertrand Chin-Ming Tan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Neurosurgery, Linkou Medical Center, Chang Gung Memorial Hospital, Linkou, Taiwan
- Research Center for Emerging Viral Infections, Chang Gung University, Taoyuan, Taiwan
| | - Yun-Wen Chen
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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3
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Roberts FL, Cataldo LR, Fex M. Monoamines' role in islet cell function and type 2 diabetes risk. Trends Mol Med 2023; 29:1045-1058. [PMID: 37722934 DOI: 10.1016/j.molmed.2023.08.009] [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: 06/27/2023] [Revised: 08/22/2023] [Accepted: 08/25/2023] [Indexed: 09/20/2023]
Abstract
The two monoamines serotonin and melatonin have recently been highlighted as potent regulators of islet hormone secretion and overall glucose homeostasis in the body. In fact, dysregulated signaling of both amines are implicated in β-cell dysfunction and development of type 2 diabetes mellitus (T2DM). Serotonin is a key player in β-cell physiology and plays a role in expansion of β-cell mass. Melatonin regulates circadian rhythm and nutrient metabolism and reduces insulin release in human and rodent islets in vitro. Herein, we focus on the role of serotonin and melatonin in islet physiology and the pathophysiology of T2DM. This includes effects on hormone secretion, receptor expression, genetic variants influencing β-cell function, melatonin treatment, and compounds that alter serotonin availability and signaling.
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Affiliation(s)
- Fiona Louise Roberts
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit for Molecular Metabolism, SE-21428 Malmö, Sweden
| | - Luis Rodrigo Cataldo
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit for Molecular Metabolism, SE-21428 Malmö, Sweden; The Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Malin Fex
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit for Molecular Metabolism, SE-21428 Malmö, Sweden.
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Vaganova AN, Shemyakova TS, Lenskaia KV, Rodionov RN, Steenblock C, Gainetdinov RR. Trace Amine-Associated Receptors and Monoamine-Mediated Regulation of Insulin Secretion in Pancreatic Islets. Biomolecules 2023; 13:1618. [PMID: 38002300 PMCID: PMC10669413 DOI: 10.3390/biom13111618] [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: 09/27/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Currently, metabolic syndrome treatment includes predominantly pharmacological symptom relief and complex lifestyle changes. Trace amines and their receptor systems modulate signaling pathways of dopamine, norepinephrine, and serotonin, which are involved in the pathogenesis of this disorder. Trace amine-associated receptor 1 (TAAR1) is expressed in endocrine organs, and it was revealed that TAAR1 may regulate insulin secretion in pancreatic islet β-cells. For instance, accumulating data demonstrate the positive effect of TAAR1 agonists on the dynamics of metabolic syndrome progression and MetS-associated disease development. The role of other TAARs (TAAR2, TAAR5, TAAR6, TAAR8, and TAAR9) in the islet's function is much less studied. In this review, we summarize the evidence of TAARs' contribution to the metabolic syndrome pathogenesis and regulation of insulin secretion in pancreatic islets. Additionally, by the analysis of public transcriptomic data, we demonstrate that TAAR1 and other TAAR receptors are expressed in the pancreatic islets. We also explore associations between the expression of TAARs mRNA and other genes in studied samples and demonstrate the deregulation of TAARs' functional associations in patients with metabolic diseases compared to healthy donors.
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Affiliation(s)
- Anastasia N. Vaganova
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia; (A.N.V.); (T.S.S.)
- St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Taisiia S. Shemyakova
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia; (A.N.V.); (T.S.S.)
| | - Karina V. Lenskaia
- Department of Medicine, St. Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia;
| | - Roman N. Rodionov
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (R.N.R.); (C.S.)
| | - Charlotte Steenblock
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (R.N.R.); (C.S.)
| | - Raul R. Gainetdinov
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia; (A.N.V.); (T.S.S.)
- St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
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Liu P, Yang Z, Wang Y, Sun A. Role of STIM1 in the Regulation of Cardiac Energy Substrate Preference. Int J Mol Sci 2023; 24:13188. [PMID: 37685995 PMCID: PMC10487555 DOI: 10.3390/ijms241713188] [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: 07/15/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
The heart requires a variety of energy substrates to maintain proper contractile function. Glucose and long-chain fatty acids (FA) are the major cardiac metabolic substrates under physiological conditions. Upon stress, a shift of cardiac substrate preference toward either glucose or FA is associated with cardiac diseases. For example, in pressure-overloaded hypertrophic hearts, there is a long-lasting substrate shift toward glucose, while in hearts with diabetic cardiomyopathy, the fuel is switched toward FA. Stromal interaction molecule 1 (STIM1), a well-established calcium (Ca2+) sensor of endoplasmic reticulum (ER) Ca2+ store, is increasingly recognized as a critical player in mediating both cardiac hypertrophy and diabetic cardiomyopathy. However, the cause-effect relationship between STIM1 and glucose/FA metabolism and the possible mechanisms by which STIM1 is involved in these cardiac metabolic diseases are poorly understood. In this review, we first discussed STIM1-dependent signaling in cardiomyocytes and metabolic changes in cardiac hypertrophy and diabetic cardiomyopathy. Second, we provided examples of the involvement of STIM1 in energy metabolism to discuss the emerging role of STIM1 in the regulation of energy substrate preference in metabolic cardiac diseases and speculated the corresponding underlying molecular mechanisms of the crosstalk between STIM1 and cardiac energy substrate preference. Finally, we briefly discussed and presented future perspectives on the possibility of targeting STIM1 to rescue cardiac metabolic diseases. Taken together, STIM1 emerges as a key player in regulating cardiac energy substrate preference, and revealing the underlying molecular mechanisms by which STIM1 mediates cardiac energy metabolism could be helpful to find novel targets to prevent or treat cardiac metabolic diseases.
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Affiliation(s)
- Panpan Liu
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Zhuli Yang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Aomin Sun
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, China
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Aslanoglou D, Bertera S, Friggeri L, Sánchez-Soto M, Lee J, Xue X, Logan RW, Lane JR, Yechoor VK, McCormick PJ, Meiler J, Free RB, Sibley DR, Bottino R, Freyberg Z. Dual pancreatic adrenergic and dopaminergic signaling as a therapeutic target of bromocriptine. iScience 2022; 25:104771. [PMID: 35982797 PMCID: PMC9379584 DOI: 10.1016/j.isci.2022.104771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 06/10/2022] [Accepted: 07/11/2022] [Indexed: 11/23/2022] Open
Abstract
Bromocriptine is approved as a diabetes therapy, yet its therapeutic mechanisms remain unclear. Though bromocriptine's actions have been mainly attributed to the stimulation of brain dopamine D2 receptors (D2R), bromocriptine also targets the pancreas. Here, we employ bromocriptine as a tool to elucidate the roles of catecholamine signaling in regulating pancreatic hormone secretion. In β-cells, bromocriptine acts on D2R and α2A-adrenergic receptor (α2A-AR) to reduce glucose-stimulated insulin secretion (GSIS). Moreover, in α-cells, bromocriptine acts via D2R to reduce glucagon secretion. α2A-AR activation by bromocriptine recruits an ensemble of G proteins with no β-arrestin2 recruitment. In contrast, D2R recruits G proteins and β-arrestin2 upon bromocriptine stimulation, demonstrating receptor-specific signaling. Docking studies reveal distinct bromocriptine binding to α2A-AR versus D2R, providing a structural basis for bromocriptine's dual actions on β-cell α2A-AR and D2R. Together, joint dopaminergic and adrenergic receptor actions on α-cell and β-cell hormone release provide a new therapeutic mechanism to improve dysglycemia.
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Affiliation(s)
- Despoina Aslanoglou
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Suzanne Bertera
- Institute of Cellular Therapeutics, Allegheny Health Network Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
| | - Laura Friggeri
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Marta Sánchez-Soto
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Jeongkyung Lee
- Diabetes and Beta Cell Biology Center, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xiangning Xue
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ryan W. Logan
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - J. Robert Lane
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, Nottingham, UK
| | - Vijay K. Yechoor
- Diabetes and Beta Cell Biology Center, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter J. McCormick
- Centre for Endocrinology, William Harvey Research Institute, Bart’s and the London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
| | - Jens Meiler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - R. Benjamin Free
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Rita Bottino
- Institute of Cellular Therapeutics, Allegheny Health Network Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
- Imagine Pharma, Pittsburgh, PA, USA
| | - Zachary Freyberg
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh, PA, USA
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7
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Gumpper RH, Fay JF, Roth BL. Molecular insights into the regulation of constitutive activity by RNA editing of 5HT 2C serotonin receptors. Cell Rep 2022; 40:111211. [PMID: 35977511 PMCID: PMC9422347 DOI: 10.1016/j.celrep.2022.111211] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/01/2022] [Accepted: 07/21/2022] [Indexed: 11/25/2022] Open
Abstract
RNA editing is a process by which post-transcriptional changes of mRNA nucleotides alter protein function through modification of the amino acid content. The 5HT2C serotonin receptor, which undergoes 32 distinct RNA-editing events leading to 24 protein isoforms, is a notable example of this process. These 5HT2C isoforms display differences in constitutive activity, agonist/inverse agonist potencies, and efficacies. To elucidate the molecular mechanisms responsible for these effects of RNA editing, we present four active-state 5HT2C-transducer-coupled structures of three representative isoforms (INI, VGV, and VSV) with the selective drug lorcaserin (Belviq) and the classic psychedelic psilocin. We also provide a comprehensive analysis of agonist activation and constitutive activity across all 24 protein isoforms. Collectively, these findings reveal a unique hydrogen-bonding network located on intracellular loop 2 that is subject to RNA editing, which differentially affects GPCR constitutive and agonist signaling activities. It is established that the 5HT2C receptor undergoes RNA editing leading to 24 isoforms. Several isoforms exhibit changes in basal activity and are linked to pathologies. Gumpper et al. have done a systematic structure-function characterization of all the isoforms revealing the underlying mechanisms that govern basal activity of the 5HT2C receptor.
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Affiliation(s)
- Ryan H Gumpper
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
| | - Jonathan F Fay
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
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