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Zhang W, Miura A, Abu Saleh MM, Shimizu K, Mita Y, Tanida R, Hirako S, Shioda S, Gmyr V, Kerr-Conte J, Pattou F, Jin C, Kanai Y, Sasaki K, Minamino N, Sakoda H, Nakazato M. The NERP-4-SNAT2 axis regulates pancreatic β-cell maintenance and function. Nat Commun 2023; 14:8158. [PMID: 38071217 PMCID: PMC10710447 DOI: 10.1038/s41467-023-43976-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Insulin secretion from pancreatic β cells is regulated by multiple stimuli, including nutrients, hormones, neuronal inputs, and local signalling. Amino acids modulate insulin secretion via amino acid transporters expressed on β cells. The granin protein VGF has dual roles in β cells: regulating secretory granule formation and functioning as a multiple peptide precursor. A VGF-derived peptide, neuroendocrine regulatory peptide-4 (NERP-4), increases Ca2+ influx in the pancreata of transgenic mice expressing apoaequorin, a Ca2+-induced bioluminescent protein complex. NERP-4 enhances glucose-stimulated insulin secretion from isolated human and mouse islets and β-cell-derived MIN6-K8 cells. NERP-4 administration reverses the impairment of β-cell maintenance and function in db/db mice by enhancing mitochondrial function and reducing metabolic stress. NERP-4 acts on sodium-coupled neutral amino acid transporter 2 (SNAT2), thereby increasing glutamine, alanine, and proline uptake into β cells and stimulating insulin secretion. SNAT2 deletion and inhibition abolish the protective effects of NERP-4 on β-cell maintenance. These findings demonstrate a novel autocrine mechanism of β-cell maintenance and function that is mediated by the peptide-amino acid transporter axis.
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Affiliation(s)
- Weidong Zhang
- Department of Bioregulatory Sciences, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Ayako Miura
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Department of Pharmacology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Md Moin Abu Saleh
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Department of Postgraduate Studies and Research, Royal College of Surgeons in Ireland - Bahrain, Busaiteen, Bahrain
| | - Koichiro Shimizu
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Yuichiro Mita
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Ryota Tanida
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Satoshi Hirako
- Department of Health and Nutrition, University of Human Arts and Sciences, Saitama, Japan
| | - Seiji Shioda
- Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Shonan University of Medical Sciences, Yokohama, Japan
| | - Valery Gmyr
- Université de Lille, Inserm, Campus Hospitalo-Universitaire de Lille, Institut Pasteur de Lille, U1190-EGID, F-59000, Lille, France
| | - Julie Kerr-Conte
- Université de Lille, Inserm, Campus Hospitalo-Universitaire de Lille, Institut Pasteur de Lille, U1190-EGID, F-59000, Lille, France
| | - Francois Pattou
- Université de Lille, Inserm, Campus Hospitalo-Universitaire de Lille, Institut Pasteur de Lille, U1190-EGID, F-59000, Lille, France
| | - Chunhuan Jin
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshikatsu Kanai
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kazuki Sasaki
- Department of Peptidomics, Sasaki Foundation, Tokyo, Japan
| | - Naoto Minamino
- Department of Molecular Pharmacology, National Cerebral and Cardiovascular Center Research, Suita, Japan
| | - Hideyuki Sakoda
- Department of Bioregulatory Sciences, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Masamitsu Nakazato
- Department of Bioregulatory Sciences, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
- Institute for Protein Research, Osaka University, Osaka, Japan.
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan.
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Kitamura S, Murao N, Yokota S, Shimizu M, Ono T, Seino Y, Suzuki A, Maejima Y, Shimomura K. Effect of fenofibrate and selective PPARα modulator (SPPARMα), pemafibrate on KATP channel activity and insulin secretion. BMC Res Notes 2023; 16:202. [PMID: 37697384 PMCID: PMC10494450 DOI: 10.1186/s13104-023-06489-7] [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: 01/10/2023] [Accepted: 09/01/2023] [Indexed: 09/13/2023] Open
Abstract
OBJECTIVE Insulin secretion is regulated by ATP-sensitive potassium (KATP) channels in pancreatic beta-cells. Peroxisome proliferator-activated receptors (PPAR) α ligands are clinically used to treat dyslipidemia. A PPARα ligand, fenofibrate, and PPARγ ligands troglitazone and 15-deoxy-∆12,14-prostaglandin J2 are known to close KATP channels and induce insulin secretion. The recently developed PPARα ligand, pemafibrate, became a new entry for treating dyslipidemia. Because pemafibrate is reported to improve glucose intolerance in mice treated with a high fat diet and a novel selective PPARα modulator, it may affect KATP channels or insulin secretion. RESULTS The effect of fenofibrate (100 µM) and pemafibrate (100 µM) on insulin secretion from MIN6 cells was measured by using batch incubation for 10 and 60 min in low (2 mM) and high (10 mM) glucose conditions. The application of fenofibrate for 10 min significantly increased insulin secretion in low glucose conditions. Pemafibrate failed to increase insulin secretion in all of the conditions experimented in this study. The KATP channel activity was measured by using whole-cell patch clamp technique. Although fenofibrate (100 µM) reduced the KATP channel current, the same concentration of pemafibrate had no effect. Both fenofibrate and pemafibrate had no effect on insulin mRNA expression.
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Affiliation(s)
- Shigeki Kitamura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, 960-1295 Japan
- Department of Plastic and Reconstructive Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Naoya Murao
- Department of Endocrinology, Diabetes and Metabolism, Fujita Health University, Toyoake, Japan
| | - Shoko Yokota
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, 960-1295 Japan
| | - Masaru Shimizu
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, 960-1295 Japan
- Department of Neurology, Matsumura General Hospital, Iwaki, Japan
| | - Tomoyuki Ono
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, 960-1295 Japan
| | - Yusuke Seino
- Department of Endocrinology, Diabetes and Metabolism, Fujita Health University, Toyoake, Japan
| | - Atsushi Suzuki
- Department of Endocrinology, Diabetes and Metabolism, Fujita Health University, Toyoake, Japan
| | - Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, 960-1295 Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, 960-1295 Japan
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3
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Zhao L, Carmean CM, Landeche M, Chellan B, Sargis RM. Selenomethionine modulates insulin secretion in the MIN6-K8 mouse insulinoma cell line. FEBS Lett 2021; 595:3042-3055. [PMID: 34780071 PMCID: PMC10924436 DOI: 10.1002/1873-3468.14232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/27/2021] [Accepted: 10/21/2021] [Indexed: 12/15/2022]
Abstract
Selenium is an essential trace element of interest for its potential role in glucose homeostasis. The present study investigated the impact of selenium supplementation as selenomethionine (SeMet) on insulin secretion in MIN6-K8 cells, a pancreatic β-cell model. We found that SeMet enhanced percent glucose-induced insulin secretion, while also increasing tolbutamide- and KCl-induced percent insulin secretion. RNA-sequencing showed that SeMet supplementation altered expression of several selenoproteins, including glutathione peroxidase 3 (Gpx3) and selenoprotein P (SelP). Targeted knockdown of Gpx3 increased both percent and total insulin release, while SelP knockdown increased insulin content and insulin release. Collectively, these studies support a putative role for selenium and selenoproteins in the regulation of insulin secretion, glucose homeostasis, and diabetes risk.
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Affiliation(s)
- Lidan Zhao
- Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, IL, USA
- Department of Medicine, College of Medicine, University of Illinois at Chicago, IL, USA
| | - Christopher M Carmean
- Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, IL, USA
- Department of Medicine, College of Medicine, University of Illinois at Chicago, IL, USA
- Chicago Center for Health and Environment (CACHET), University of Illinois at Chicago, IL, USA
| | - Michael Landeche
- Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, IL, USA
- Department of Medicine, College of Medicine, University of Illinois at Chicago, IL, USA
| | - Bijoy Chellan
- Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, IL, USA
- Department of Medicine, College of Medicine, University of Illinois at Chicago, IL, USA
| | - Robert M Sargis
- Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, IL, USA
- Department of Medicine, College of Medicine, University of Illinois at Chicago, IL, USA
- Chicago Center for Health and Environment (CACHET), University of Illinois at Chicago, IL, USA
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
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4
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Barella LF, Rossi M, Pydi SP, Meister J, Jain S, Cui Y, Gavrilova O, Fulgenzi G, Tessarollo L, Wess J. β-Arrestin-1 is required for adaptive β-cell mass expansion during obesity. Nat Commun 2021; 12:3385. [PMID: 34099679 PMCID: PMC8184739 DOI: 10.1038/s41467-021-23656-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/11/2021] [Indexed: 01/14/2023] Open
Abstract
Obesity is the key driver of peripheral insulin resistance, one of the key features of type 2 diabetes (T2D). In insulin-resistant individuals, the expansion of beta-cell mass is able to delay or even prevent the onset of overt T2D. Here, we report that beta-arrestin-1 (barr1), an intracellular protein known to regulate signaling through G protein-coupled receptors, is essential for beta-cell replication and function in insulin-resistant mice maintained on an obesogenic diet. Specifically, insulin-resistant beta-cell-specific barr1 knockout mice display marked reductions in beta-cell mass and the rate of beta-cell proliferation, associated with pronounced impairments in glucose homeostasis. Mechanistic studies suggest that the observed metabolic deficits are due to reduced Pdx1 expression levels caused by beta-cell barr1 deficiency. These findings indicate that strategies aimed at enhancing barr1 activity and/or expression in beta-cells may prove useful to restore proper glucose homeostasis in T2D.
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Affiliation(s)
- Luiz F Barella
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
| | - Mario Rossi
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Sai P Pydi
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Jaroslawna Meister
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Shanu Jain
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Yinghong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Bethesda, MD, USA
| | - Gianluca Fulgenzi
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, USA
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
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5
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Han G, Takahashi H, Murao N, Gheni G, Yokoi N, Hamamoto Y, Asahara S, Seino Y, Kido Y, Seino S. Glutamate is an essential mediator in glutamine-amplified insulin secretion. J Diabetes Investig 2021; 12:920-930. [PMID: 33417747 PMCID: PMC8169365 DOI: 10.1111/jdi.13497] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 12/28/2022] Open
Abstract
AIMS/INTRODUCTION Glutamine is the most abundant amino acid in the circulation. In this study, we investigated cell signaling in the amplification of insulin secretion by glutamine. MATERIALS AND METHODS Clonal pancreatic β-cells MIN6-K8, wild-type B6 mouse islets, glutamate dehydrogenase (GDH) knockout clonal β-cells (Glud1KOβCL), and glutamate-oxaloacetate transaminase 1 (GOT1) knockout clonal β-cells (Got1KOβCL) were studied. Insulin secretion from these cells and islets was examined under various conditions, and intracellular glutamine metabolism was assessed by metabolic flux analysis. Intracellular Ca2+ concentration ([Ca2+ ]i ) was also measured. RESULTS Glutamine dose-dependently amplified insulin secretion in the presence of high glucose in both MIN6-K8 cells and Glud1KOβCL. Inhibition of glutaminases, the enzymes that convert glutamine to glutamate, dramatically reduced the glutamine-amplifying effect on insulin secretion. A substantial amount of glutamate was produced from glutamine through direct conversion by glutaminases. Glutamine also increased [Ca2+ ]i at high glucose, which was abolished by inhibition of glutaminases. Glutamic acid dimethylester (dm-Glu), a membrane permeable glutamate precursor that is converted to glutamate in cells, increased [Ca2+ ]i as well as induced insulin secretion at high glucose. These effects of glutamine and dm-Glu were dependent on calcium influx. Glutamine also induced insulin secretion in clonal β-cells MIN6-m14, which otherwise exhibit no insulin secretory response to glucose. CONCLUSIONS Glutamate converted from glutamine is an essential mediator that enhances calcium signaling in the glutamine-amplifying effect on insulin secretion. Our data also suggest that glutamine exerts a permissive effect on glucose-induced insulin secretion.
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Affiliation(s)
- Guirong Han
- Division of Metabolism and DiseaseDepartment of BiophysicsKobe University Graduate School of Health SciencesKobeJapan
- Division of Molecular and Metabolic MedicineDepartment of Physiology and Cell BiologyKobe University Graduate School of MedicineKobeJapan
- Kansai Electric Power Medical Research InstituteKobeJapan
| | - Harumi Takahashi
- Division of Molecular and Metabolic MedicineDepartment of Physiology and Cell BiologyKobe University Graduate School of MedicineKobeJapan
| | - Naoya Murao
- Division of Molecular and Metabolic MedicineDepartment of Physiology and Cell BiologyKobe University Graduate School of MedicineKobeJapan
| | - Ghupurjan Gheni
- Division of Molecular and Metabolic MedicineDepartment of Physiology and Cell BiologyKobe University Graduate School of MedicineKobeJapan
| | - Norihide Yokoi
- Division of Molecular and Metabolic MedicineDepartment of Physiology and Cell BiologyKobe University Graduate School of MedicineKobeJapan
- Laboratory of Animal Breeding and GeneticsGraduate School of AgricultureKyoto UniversityKyotoJapan
| | | | - Shun‐ichiro Asahara
- Division of Diabetes and EndocrinologyDepartment of Internal MedicineKobe University Graduate School of MedicineKobeJapan
| | - Yutaka Seino
- Kansai Electric Power Medical Research InstituteKobeJapan
| | - Yoshiaki Kido
- Division of Metabolism and DiseaseDepartment of BiophysicsKobe University Graduate School of Health SciencesKobeJapan
- Division of Diabetes and EndocrinologyDepartment of Internal MedicineKobe University Graduate School of MedicineKobeJapan
| | - Susumu Seino
- Division of Molecular and Metabolic MedicineDepartment of Physiology and Cell BiologyKobe University Graduate School of MedicineKobeJapan
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6
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Carmean CM, Zhao L, Landeche M, Chellan B, Sargis RM. Dimethyl sulfoxide acutely enhances regulated insulin secretion in the MIN6-K8 mouse insulinoma cell line. Histochem Cell Biol 2021; 156:69-73. [PMID: 33743067 DOI: 10.1007/s00418-021-01984-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2021] [Indexed: 11/29/2022]
Abstract
Diabetes mellitus is a metabolic disorder projected to afflict 700 million people globally by 2045. Fundamental to the progression of diabetes is an insufficient supply of insulin to meet metabolic demand. The MIN6-K8 cell line is a mouse insulinoma model of pancreatic β-cells frequently used to study the mechanisms of insulin secretion. Here, we evaluated the effects of short-term exposure to dimethyl sulfoxide (DMSO), a polar aprotic solvent commonly used in drug screening, on physiological characteristics of MIN6-K8 cells. Short-term exposure of MIN6-K8 cells to DMSO enhanced glucose-induced and tolbutamide-stimulated insulin secretion without significant effects on basal secretion or potassium responsiveness. Calcium influx was enhanced during glucose and tolbutamide treatments, suggesting that DMSO's mechanism of action is upstream of calcium-dependent insulin granule exocytosis. Based on these studies, investigators should use caution when conducting experiments with DMSO in the MIN6-K8 cell line and should report all DMSO concentrations when used as a solvent.
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Affiliation(s)
- Christopher M Carmean
- Division of Endocrinology, Diabetes, and Metabolism; Department of Medicine, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott, Suite E625, M/C 640, Chicago, IL, 60612, USA. .,Chicago Center for Health and Environment (CACHET), University of Illinois at Chicago, Chicago, IL, USA.
| | - Lidan Zhao
- Division of Endocrinology, Diabetes, and Metabolism; Department of Medicine, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott, Suite E625, M/C 640, Chicago, IL, 60612, USA
| | - Michael Landeche
- Division of Endocrinology, Diabetes, and Metabolism; Department of Medicine, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott, Suite E625, M/C 640, Chicago, IL, 60612, USA
| | - Bijoy Chellan
- Division of Endocrinology, Diabetes, and Metabolism; Department of Medicine, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott, Suite E625, M/C 640, Chicago, IL, 60612, USA
| | - Robert M Sargis
- Division of Endocrinology, Diabetes, and Metabolism; Department of Medicine, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott, Suite E625, M/C 640, Chicago, IL, 60612, USA.,Chicago Center for Health and Environment (CACHET), University of Illinois at Chicago, Chicago, IL, USA.,Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
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7
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Oduori OS, Murao N, Shimomura K, Takahashi H, Zhang Q, Dou H, Sakai S, Minami K, Chanclon B, Guida C, Kothegala L, Tolö J, Maejima Y, Yokoi N, Minami Y, Miki T, Rorsman P, Seino S. Gs/Gq signaling switch in β cells defines incretin effectiveness in diabetes. J Clin Invest 2021; 130:6639-6655. [PMID: 33196462 DOI: 10.1172/jci140046] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
By restoring glucose-regulated insulin secretion, glucagon-like peptide-1-based (GLP-1-based) therapies are becoming increasingly important in diabetes care. Normally, the incretins GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) jointly maintain normal blood glucose levels by stimulation of insulin secretion in pancreatic β cells. However, the reason why only GLP-1-based drugs are effective in improving insulin secretion after presentation of diabetes has not been resolved. ATP-sensitive K+ (KATP) channels play a crucial role in coupling the systemic metabolic status to β cell electrical activity for insulin secretion. Here, we have shown that persistent membrane depolarization of β cells due to genetic (β cell-specific Kcnj11-/- mice) or pharmacological (long-term exposure to sulfonylureas) inhibition of the KATP channel led to a switch from Gs to Gq in a major amplifying pathway of insulin secretion. The switch determined the relative insulinotropic effectiveness of GLP-1 and GIP, as GLP-1 can activate both Gq and Gs, while GIP only activates Gs. The findings were corroborated in other models of persistent depolarization: a spontaneous diabetic KK-Ay mouse and nondiabetic human and mouse β cells of pancreatic islets chronically treated with high glucose. Thus, a Gs/Gq signaling switch in β cells exposed to chronic hyperglycemia underlies the differential insulinotropic potential of incretins in diabetes.
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Affiliation(s)
- Okechi S Oduori
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Murao
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Haiqiang Dou
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Shihomi Sakai
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohtaro Minami
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Belen Chanclon
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lakshmi Kothegala
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Johan Tolö
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.,Laboratory of Animal Breeding and Genetics, Division of Applied Biosciences, Kyoto University Graduate School of Agriculture, Kyoto, Japan
| | - Yasuhiro Minami
- Division of Cell Physiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takashi Miki
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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8
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Miyazaki S, Tashiro F, Tsuchiya T, Sasaki K, Miyazaki JI. Establishment of a long-term stable β-cell line and its application to analyze the effect of Gcg expression on insulin secretion. Sci Rep 2021; 11:477. [PMID: 33436850 PMCID: PMC7804151 DOI: 10.1038/s41598-020-79992-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/15/2020] [Indexed: 01/29/2023] Open
Abstract
A pancreatic β-cell line MIN6 was previously established in our lab from an insulinoma developed in an IT6 transgenic mouse expressing the SV40 T antigen in β-cells. This cell line has been widely used for in vitro analysis of β-cell function, but tends to lose the mature β-cell features, including glucose-stimulated insulin secretion (GSIS), in long-term culture. The aim of this study was to develop a stable β-cell line that retains the characteristics of mature β-cells. Considering that mice derived from a cross between C3H and C57BL/6 strains are known to exhibit higher insulin secretory capacity than C57BL/6 mice, an IT6 male mouse of this hybrid background was used to isolate insulinomas, which were independently cultured. After 7 months of continuous culturing, we obtained the MIN6-CB4 β-cell line, which stably maintains its GSIS. It has been noted that β-cell lines express the glucagon (Gcg) gene at certain levels. MIN6-CB4 cells were utilized to assess the effects of differential Gcg expression on β-cell function. Our data show the functional importance of Gcg expression and resulting basal activation of the GLP-1 receptor in β-cells. MIN6-CB4 cells can serve as an invaluable tool for studying the regulatory mechanisms of insulin secretion, such as the GLP-1/cAMP signaling, in β-cells.
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Affiliation(s)
- Satsuki Miyazaki
- grid.136593.b0000 0004 0373 3971Division of Stem Cell Regulation Research, Center for Medical Research and Education, Osaka University Graduate School of Medicine, Suita, Osaka Japan
| | - Fumi Tashiro
- grid.136593.b0000 0004 0373 3971Division of Stem Cell Regulation Research, Center for Medical Research and Education, Osaka University Graduate School of Medicine, Suita, Osaka Japan
| | - Takashi Tsuchiya
- grid.410796.d0000 0004 0378 8307National Cerebral and Cardiovascular Center, Suita, Osaka Japan
| | - Kazuki Sasaki
- grid.410796.d0000 0004 0378 8307National Cerebral and Cardiovascular Center, Suita, Osaka Japan ,grid.419521.a0000 0004 1763 8692Present Address: Sasaki Institute, 2-2, Kandasurugadai, Chiyoda-ku, Tokyo, 101-0062 Japan
| | - Jun-ichi Miyazaki
- grid.136593.b0000 0004 0373 3971The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 560-0047 Japan
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Malendowicz LK, Rucinski M. Neuromedins NMU and NMS: An Updated Overview of Their Functions. Front Endocrinol (Lausanne) 2021; 12:713961. [PMID: 34276571 PMCID: PMC8283259 DOI: 10.3389/fendo.2021.713961] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/21/2021] [Indexed: 11/19/2022] Open
Abstract
More than 35 years have passed since the identification of neuromedin U (NMU). Dozens of publications have been devoted to its physiological role in the organism, which have provided insight into its occurrence in the body, its synthesis and mechanism of action at the cellular level. Two G protein-coupled receptors (GPCRs) have been identified, with NMUR1 distributed mainly peripherally and NMUR2 predominantly centrally. Recognition of the role of NMU in the control of energy homeostasis of the body has greatly increased interest in this neuromedin. In 2005 a second, structurally related peptide, neuromedin S (NMS) was identified. The expression of NMS is more restricted, it is predominantly found in the central nervous system. In recent years, further peptides related to NMU and NMS have been identified. These are neuromedin U precursor related peptide (NURP) and neuromedin S precursor related peptide (NSRP), which also exert biological effects without acting via NMUR1, or NMUR2. This observation suggests the presence of another, as yet unrecognized receptor. Another unresolved issue within the NMU/NMS system is the differences in the effects of various NMU isoforms on diverse cell lines. It seems that development of highly specific NMUR1 and NMUR2 receptor antagonists would allow for a more detailed understanding of the mechanisms of action of NMU/NMS and related peptides in the body. They could form the basis for attempts to use such compounds in the treatment of disorders, for example, metabolic disorders, circadian rhythm, stress, etc.
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Allosteric modulation of β-cell M 3 muscarinic acetylcholine receptors greatly improves glucose homeostasis in lean and obese mice. Proc Natl Acad Sci U S A 2019; 116:18684-18690. [PMID: 31451647 DOI: 10.1073/pnas.1904943116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Given the global epidemic in type 2 diabetes, novel antidiabetic drugs with increased efficacy and reduced side effects are urgently needed. Previous work has shown that M3 muscarinic acetylcholine (ACh) receptors (M3Rs) expressed by pancreatic β cells play key roles in stimulating insulin secretion and maintaining physiological blood glucose levels. In the present study, we tested the hypothesis that a positive allosteric modulator (PAM) of M3R function can improve glucose homeostasis in mice by promoting insulin release. One major advantage of this approach is that allosteric agents respect the ACh-dependent spatiotemporal control of M3R activity. In this study, we first demonstrated that VU0119498, a drug known to act as a PAM at M3Rs, significantly augmented ACh-induced insulin release from cultured β cells and mouse and human pancreatic islets. This stimulatory effect was absent in islets prepared from mice lacking M3Rs, indicative of the involvement of M3Rs. VU0119498 treatment of wild-type mice caused a significant increase in plasma insulin levels, accompanied by a striking improvement in glucose tolerance. These effects were mediated by β-cell M3Rs, since they were absent in mutant mice selectively lacking M3Rs in β cells. Moreover, acute VU0119498 treatment of obese, glucose-intolerant mice triggered enhanced insulin release and restored normal glucose tolerance. Interestingly, doses of VU0119498 that led to pronounced improvements in glucose homeostasis did not cause any significant side effects due to activation of M3Rs expressed by other peripheral cell types. Taken together, the data from this proof-of-concept study strongly suggest that M3R PAMs may become clinically useful as novel antidiabetic agents.
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11
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Barella LF, Rossi M, Zhu L, Cui Y, Mei FC, Cheng X, Chen W, Gurevich VV, Wess J. β-Cell-intrinsic β-arrestin 1 signaling enhances sulfonylurea-induced insulin secretion. J Clin Invest 2019; 129:3732-3737. [PMID: 31184597 DOI: 10.1172/jci126309] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Beta-arrestin-1 and -2 (Barr1 and Barr2, respectively) are intracellular signaling molecules that regulate many important metabolic functions. We previously demonstrated that mice lacking Barr2 selectively in pancreatic beta-cells showed pronounced metabolic impairments. Here we investigated whether Barr1 plays a similar role in regulating beta-cell function and whole body glucose homeostasis. Initially, we inactivated the Barr1 gene in beta-cells of adult mice (beta-barr1-KO mice). Beta-barr1-KO mice did not display any obvious phenotypes in a series of in vivo and in vitro metabolic tests. However, glibenclamide and tolbutamide, two widely used antidiabetic drugs of the sulfonylurea (SU) family, showed greatly reduced efficacy in stimulating insulin secretion in the KO mice in vivo and in perifused KO islets in vitro. Additional in vivo and in vitro studies demonstrated that Barr1 enhanced SU-stimulated insulin secretion by promoting SU-mediated activation of Epac2. Pull-down and co-immunoprecipitation experiments showed that Barr1 can directly interact with Epac2 and that SUs such as glibenclamide promote Barr1/Epac2 complex formation, triggering enhanced Rap1 signaling and insulin secretion. These findings suggest that strategies aimed at promoting Barr1 signaling in beta-cells may prove useful for the development of efficacious antidiabetic drugs.
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Affiliation(s)
- Luiz F Barella
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Mario Rossi
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Lu Zhu
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Yinghong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Fang C Mei
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Xiaodong Cheng
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Wei Chen
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
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12
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Carmean CM, Yokoi N, Takahashi H, Oduori OS, Kang C, Kanagawa A, Kirkley AG, Han G, Landeche M, Hidaka S, Katoh M, Sargis RM, Seino S. Arsenic modifies serotonin metabolism through glucuronidation in pancreatic β-cells. Am J Physiol Endocrinol Metab 2019; 316:E464-E474. [PMID: 30562058 PMCID: PMC6459295 DOI: 10.1152/ajpendo.00302.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In arsenic-endemic regions of the world, arsenic exposure correlates with diabetes mellitus. Multiple animal models of inorganic arsenic (iAs, as As3+) exposure have revealed that iAs-induced glucose intolerance manifests as a result of pancreatic β-cell dysfunction. To define the mechanisms responsible for this β-cell defect, the MIN6-K8 mouse β-cell line was exposed to environmentally relevant doses of iAs. Exposure to 0.1-1 µM iAs for 3 days significantly decreased glucose-induced insulin secretion (GIIS). Serotonin and its precursor, 5-hydroxytryptophan (5-HTP), were both decreased. Supplementation with 5-HTP, which loads the system with bioavailable 5-HTP and serotonin, rescued GIIS, suggesting that recovery of this pathway was sufficient to restore function. Exposure to iAs was accompanied by an increase in mRNA expression of UDP-glucuronosyltransferase 1 family, polypeptide a6a (Ugt1a6a), a phase-II detoxification enzyme that facilitates the disposal of cyclic amines, including serotonin, via glucuronidation. Elevated Ugt1a6a and UGT1A6 expression levels were observed in mouse and human islets, respectively, following 3 days of iAs exposure. Consistent with this finding, the enzymatic rate of serotonin glucuronidation was increased in iAs-exposed cells. Knockdown by siRNA of Ugt1a6a during iAs exposure restored GIIS in MIN6-K8 cells. This effect was prevented by blockade of serotonin biosynthesis, suggesting that the observed iAs-induced increase in Ugt1a6a affects GIIS by targeting serotonin or serotonin-related metabolites. Although it is not yet clear exactly which element(s) of the serotonin pathway is/are most responsible for iAs-induced GIIS dysfunction, this study provides evidence that UGT1A6A, acting on the serotonin pathway, regulates GIIS under both normal and pathological conditions.
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Affiliation(s)
- Christopher M Carmean
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
- Kansai Electric Power Medical Research Institute , Kobe , Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
- Kansai Electric Power Medical Research Institute , Kobe , Japan
| | - Okechi S Oduori
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
| | - Christie Kang
- Department of Pathology, College of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Akiko Kanagawa
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
| | - Andrew G Kirkley
- Committee on Molecular Pathogenesis and Molecular Medicine, University of Chicago , Chicago, Illinois
| | - Guirong Han
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
- Kansai Electric Power Medical Research Institute , Kobe , Japan
- Division of Metabolism and Disease, Department of Biophysics, Kobe University Graduate School of Health Sciences , Kobe , Japan
| | - Michael Landeche
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, College of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Shihomi Hidaka
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
| | - Miki Katoh
- Department of Pharmaceutics, Faculty of Pharmacy, Meijo University , Nagoya , Japan
| | - Robert M Sargis
- Department of Pathology, College of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, College of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine , Kobe , Japan
- Kansai Electric Power Medical Research Institute , Kobe , Japan
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13
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Murase M, Seino Y, Maekawa R, Iida A, Hosokawa K, Hayami T, Tsunekawa S, Hamada Y, Yokoi N, Seino S, Hayashi Y, Arima H. Functional adenosine triphosphate-sensitive potassium channel is required in high-carbohydrate diet-induced increase in β-cell mass. J Diabetes Investig 2019; 10:238-250. [PMID: 30084544 PMCID: PMC6400177 DOI: 10.1111/jdi.12907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 07/26/2018] [Accepted: 08/01/2018] [Indexed: 12/22/2022] Open
Abstract
AIMS/INTRODUCTION A high-carbohydrate diet is known to increase insulin secretion and induce obesity. However, whether or not a high-carbohydrate diet affects β-cell mass (BCM) has been little investigated. MATERIALS AND METHODS Both wild-type (WT) mice and adenosine triphosphate-sensitive potassium channel-deficient (Kir6.2KO) mice were fed normal chow or high-starch (ST) diets for 22 weeks. BCM and the numbers of islets were analyzed by immunohistochemistry, and gene expression levels in islets were investigated by quantitative real-time reverse transcription polymerase chain reaction. MIN6-K8 β-cells were stimulated in solution containing various concentrations of glucose combined with nifedipine and glimepiride, and gene expression was analyzed. RESULTS Both WT and Kir6.2KO mice fed ST showed hyperinsulinemia and body weight gain. BCM, the number of islets and the expression levels of cyclinD2 messenger ribonucleic acid were increased in WT mice fed ST compared with those in WT mice fed normal chow. In contrast, no significant difference in BCM, the number of islets or the expression levels of cyclinD2 messenger ribonucleic acid were observed between Kir6.2KO mice fed normal chow and those fed ST. Incubation of MIN6-K8 β-cells in high-glucose media or with glimepiride increased cyclinD2 expression, whereas nifedipine attenuated a high-glucose-induced increase in cyclinD2 expression. CONCLUSIONS These results show that a high-starch diet increases BCM in an adenosine triphosphate-sensitive potassium channel-dependent manner, which is mediated through upregulation of cyclinD2 expression.
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Affiliation(s)
- Masatoshi Murase
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Yusuke Seino
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Ryuya Maekawa
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Atsushi Iida
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Kaori Hosokawa
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Tomohide Hayami
- Division of Molecular and Metabolic MedicineKobe University Graduate School of MedicineKobeJapan
- Yutaka Seino Distinguished Center for Diabetes ResearchKansai Electric Power Medical Research InstituteKobeJapan
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Shin Tsunekawa
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Yoji Hamada
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
| | - Norihide Yokoi
- Division of Molecular and Metabolic MedicineKobe University Graduate School of MedicineKobeJapan
| | - Susumu Seino
- Division of Molecular and Metabolic MedicineKobe University Graduate School of MedicineKobeJapan
| | - Yoshitaka Hayashi
- Division of Stress Adaptation and ProtectionDepartment of Genetics ResearchInstitute of Environmental MedicineNagoya UniversityNagoyaJapan
| | - Hiroshi Arima
- Departments of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoyaJapan
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14
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Mohiuddin MS, Himeno T, Inoue R, Miura-Yura E, Yamada Y, Nakai-Shimoda H, Asano S, Kato M, Motegi M, Kondo M, Seino Y, Tsunekawa S, Kato Y, Suzuki A, Naruse K, Kato K, Nakamura J, Kamiya H. Glucagon-Like Peptide-1 Receptor Agonist Protects Dorsal Root Ganglion Neurons against Oxidative Insult. J Diabetes Res 2019; 2019:9426014. [PMID: 30918901 PMCID: PMC6408997 DOI: 10.1155/2019/9426014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/23/2018] [Accepted: 12/30/2018] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Diabetic polyneuropathy (DPN) is one of the most prevalent diabetic complications. We previously demonstrated that exendin-4 (Ex4), a glucagon-like peptide-1 receptor agonist (GLP-1RA), has beneficial effects in animal models of DPN. We hypothesized that GLP-1 signaling would protect neurons of the peripheral nervous system from oxidative insult in DPN. Here, the therapeutic potential of GLP-1RAs on DPN was investigated in depth using the cellular oxidative insult model applied to the dorsal root ganglion (DRG) neuronal cell line. RESEARCH DESIGN AND METHODS Immortalized DRG neuronal 50B11 cells were cultured with and without hydrogen peroxide in the presence or absence of Ex4 or GLP-1(7-37). Cytotoxicity and viability were determined using a lactate dehydrogenase assay and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt), respectively. Antioxidant enzyme activity was evaluated using a superoxide dismutase assay. Alteration of neuronal characteristics of 50B11 cells induced by GLP-1RAs was evaluated with immunocytochemistry utilizing antibodies for transient receptor potential vanilloid subfamily member 1, substance P, and calcitonin gene-related peptide. Cell proliferation and apoptosis were also examined by ethynyl deoxyuridine incorporation assay and APOPercentage dye, respectively. The neurite projection ratio induced by treatment with GLP-1RAs was counted. Intracellular activation of adenylate cyclase/cyclic adenosine monophosphate (cAMP) signaling was also quantified after treatment with GLP-1RAs. RESULTS Neither Ex4 nor GLP-1(7-37) demonstrated cytotoxicity in the cells. An MTS assay revealed that GLP-1RAs amended impaired cell viability induced by oxidative insult in 50B11 cells. GLP-1RAs activated superoxide dismutase. GLP-1RAs induced no alteration of the distribution pattern in neuronal markers. Ex4 rescued the cells from oxidative insult-induced apoptosis. GLP-1RAs suppressed proliferation and promoted neurite projections. No GLP-1RAs induced an accumulation of cAMP. CONCLUSIONS Our findings indicate that GLP-1RAs have neuroprotective potential which is achieved by their direct actions on DRG neurons. Beneficial effects of GLP-1RAs on DPN could be related to these direct actions on DRG neurons.
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Affiliation(s)
- Mohammad Sarif Mohiuddin
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Tatsuhito Himeno
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Rieko Inoue
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Emiri Miura-Yura
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Yuichiro Yamada
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Hiromi Nakai-Shimoda
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Saeko Asano
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Makoto Kato
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Mikio Motegi
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Masaki Kondo
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Yusuke Seino
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Shin Tsunekawa
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Yoshiro Kato
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Atsushi Suzuki
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Keiko Naruse
- Department of Internal Medicine, Aichi Gakuin University School of Dentistry, Nagoya, Japan
| | - Koichi Kato
- Department of Medicine, Aichi Gakuin University School of Pharmacy, Nagoya, Japan
| | - Jiro Nakamura
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Hideki Kamiya
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
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15
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TAKAHASHI H, YOKOI N, SEINO S. Glutamate as intracellular and extracellular signals in pancreatic islet functions. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2019; 95:246-260. [PMID: 31189778 PMCID: PMC6751295 DOI: 10.2183/pjab.95.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/08/2019] [Indexed: 05/25/2023]
Abstract
l-Glutamate is one of the most abundant amino acids in the body and is a constituent of proteins and a substrate in metabolism. It is well known that glutamate serves as a primary excitatory neurotransmitter and a critical neuromodulator in the brain. Recent studies have shown that in addition to its pivotal role in neural functions, glutamate plays many important roles in a variety of cellular functions, including those as intracellular and extracellular signals. In pancreatic islets, glutamate is now known to be required for the normal regulation of insulin secretion, such as incretin-induced insulin secretion. In this review, we primarily discuss the physiological and pathophysiological roles of glutamate as intracellular and extracellular signals in the functions of pancreatic islets.
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Affiliation(s)
- Harumi TAKAHASHI
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Norihide YOKOI
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Susumu SEINO
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
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16
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Kitamoto T, Sakurai K, Lee EY, Yokote K, Accili D, Miki T. Distinct roles of systemic and local actions of insulin on pancreatic β-cells. Metabolism 2018; 82:100-110. [PMID: 29320716 PMCID: PMC7391221 DOI: 10.1016/j.metabol.2017.12.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 12/16/2017] [Accepted: 12/31/2017] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Pancreatic β-cell mass and function are critical in glucose homeostasis. Their regulatory mechanisms have been studied principally under experimental conditions of reduced β-cell numbers, such as β-cell ablation and partial pancreatectomy. In the present study, we generated an opposite mouse model with an excessive amount of ectopic β-cells, and analyzed its consequence on β-cell mass and survival. METHODS Mice underwent sub-renal transplantation (SRT) of pseudo-islets generated from a pancreatic β-cell line MIN6 or intra-pancreatic transplantation (IPT) of MIN6 cells, and morphological and functional changes of their endocrine pancreata were analyzed. Cellular fate of pancreatic β-cells after transplantation was traced using RipCre:Rosa26-tdTomato mice. By using MIN6 cells, we evaluated the roles of extracellular glucose, membrane potential, and insulin signaling on β-cell survival. RESULTS SRT mice developed severe, progressive hypoglycemia associated with marked reduction in insulin-positive (Ins+) cell mass and apparent increase in apoptotic Ins+ cells. In in vitro experiments of MIN6 cells, insulin signaling blockade potently induced cell death, suggesting that local insulin action is required for β-cell survival. In fact, IPT (i.e. transplantation close to endogenous β-cells) resulted in fewer apoptotic Ins+ cells compared with those induced by SRT. On the other hand, β-cell mass was decreased in proportion to the decrease in blood glucose levels in both SRT and IPT mice, suggesting a contribution of hypoglycemia induced by systemic hyperinsulinemia. CONCLUSION Insulin plays distinct roles in β-cell survival and β-cell mass regulation through its local and systemic actions on β-cells, respectively.
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Affiliation(s)
- Takumi Kitamoto
- Department of Medical Physiology, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan; Department of Clinical Cell Biology and Medicine, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan; Division of Endocrinology, Department of Medicine, Columbia University, New York 10032, USA
| | - Kenichi Sakurai
- Center for Preventive Medical Sciences, Chiba University, Chiba 263-8522, Japan
| | - Eun Young Lee
- Department of Medical Physiology, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan
| | - Koutaro Yokote
- Department of Clinical Cell Biology and Medicine, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan
| | - Domenico Accili
- Division of Endocrinology, Department of Medicine, Columbia University, New York 10032, USA
| | - Takashi Miki
- Department of Medical Physiology, Chiba University, Graduate School of Medicine, Chiba 260-8670, Japan.
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17
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Munakata Y, Yamada T, Imai J, Takahashi K, Tsukita S, Shirai Y, Kodama S, Asai Y, Sugisawa T, Chiba Y, Kaneko K, Uno K, Sawada S, Hatakeyama H, Kanzaki M, Miyazaki JI, Oka Y, Katagiri H. Olfactory receptors are expressed in pancreatic β-cells and promote glucose-stimulated insulin secretion. Sci Rep 2018; 8:1499. [PMID: 29367680 PMCID: PMC5784078 DOI: 10.1038/s41598-018-19765-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 01/04/2018] [Indexed: 11/25/2022] Open
Abstract
Olfactory receptors (ORs) mediate olfactory chemo-sensation in OR neurons. Herein, we have demonstrated that the OR chemo-sensing machinery functions in pancreatic β-cells and modulates insulin secretion. First, we found several OR isoforms, including OLFR15 and OLFR821, to be expressed in pancreatic islets and a β-cell line, MIN6. Immunostaining revealed OLFR15 and OLFR821 to be uniformly expressed in pancreatic β-cells. In addition, mRNAs of Olfr15 and Olfr821 were detected in single MIN6 cells. These results indicate that multiple ORs are simultaneously expressed in individual β-cells. Octanoic acid, which is a medium-chain fatty acid contained in food and reportedly interacts with OLFR15, potentiated glucose-stimulated insulin secretion (GSIS), thereby improving glucose tolerance in vivo. GSIS potentiation by octanoic acid was confirmed in isolated pancreatic islets and MIN6 cells and was blocked by OLFR15 knockdown. While Gαolf expression was not detectable in β-cells, experiments using inhibitors and siRNA revealed that the pathway dependent on phospholipase C-inositol triphosphate, rather than cAMP-protein kinase A, mediates GSIS potentiation via OLFR15. These findings suggest that the OR system in pancreatic β-cells has a chemo-sensor function allowing recognition of environmental substances obtained from food, and potentiates insulin secretion in a cell-autonomous manner, thereby modulating systemic glucose metabolism.
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Affiliation(s)
- Yuichiro Munakata
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Tetsuya Yamada
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan. .,Center for Metabolic Diseases, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.
| | - Junta Imai
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Kei Takahashi
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Sohei Tsukita
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Yuta Shirai
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Shinjiro Kodama
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Yoichiro Asai
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Takashi Sugisawa
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Yumiko Chiba
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Keizo Kaneko
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Kenji Uno
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Shojiro Sawada
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Hiroyasu Hatakeyama
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, 980-8579, Japan
| | - Makoto Kanzaki
- Center for Metabolic Diseases, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.,Graduate School of Biomedical Engineering, Tohoku University, Sendai, 980-8579, Japan
| | - Jun-Ichi Miyazaki
- Division of Stem Cell Regulation Research, Osaka University Graduate School of Medicine, Suita, 565-0871, Japan
| | - Yoshitomo Oka
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Hideki Katagiri
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.,Center for Metabolic Diseases, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.,Japan Agency for Medical Research and Development (AMED), CREST, Chiyoda-ku, Tokyo, 100-0004, Japan
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18
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Jiao A, Li F, Zhang C, Lv W, Chen B, Zhang J. Simulated Cholinergic Reinnervation of β (INS-1) Cells: Antidiabetic Utility of Heterotypic Pseudoislets Containing β Cell and Cholinergic Cell. Int J Endocrinol 2018; 2018:1505307. [PMID: 29755519 PMCID: PMC5884158 DOI: 10.1155/2018/1505307] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 01/02/2018] [Accepted: 01/17/2018] [Indexed: 12/30/2022] Open
Abstract
Cholinergic neurons can functionally support pancreatic islets in controlling blood sugar levels. However, in islet transplantation, the level of cholinergic reinnervation is significantly lower compared to orthotopic pancreatic islets. This abnormal reinnervation affects the survival and function of islet grafts. In this study, the cholinergic reinnervation of beta cells was simulated by 2D and 3D coculture of INS-1 and NG108-15 cells. In 2D culture conditions, 20 mM glucose induced a 1.24-fold increase (p < 0.0001) in insulin secretion from the coculture group, while in the 3D culture condition, a 1.78-fold increase (p < 0.0001) in insulin secretion from heterotypic pseudoislet group was observed. Glucose-stimulated insulin secretion (GSIS) from 2D INS-1 cells showed minimal changes when compared to 3D structures. E-cadherin expressed in INS-1 and NG108-15 cells was the key adhesion molecule for the formation of heterotypic pseudoislets. NG108-15 cells hardly affected the proliferation of INS-1 cells in vitro. Heterotypic pseudoislet transplantation recipient mice reverted to normoglycemic levels faster and had a greater blood glucose clearance compared to INS-1 pseudoislet recipient mice. In conclusion, cholinergic cells can promote insulin-secreting cells to function better in vitro and in vivo and E-cadherin plays an important role in the formation of heterotypic pseudoislets.
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Affiliation(s)
- Ao Jiao
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China
| | - Feng Li
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China
| | - Chengshuo Zhang
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China
| | - Wu Lv
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China
| | - Baomin Chen
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China
| | - Jialin Zhang
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China
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19
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Murao N, Yokoi N, Honda K, Han G, Hayami T, Gheni G, Takahashi H, Minami K, Seino S. Essential roles of aspartate aminotransferase 1 and vesicular glutamate transporters in β-cell glutamate signaling for incretin-induced insulin secretion. PLoS One 2017; 12:e0187213. [PMID: 29091932 PMCID: PMC5665537 DOI: 10.1371/journal.pone.0187213] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/16/2017] [Indexed: 01/18/2023] Open
Abstract
Incretins (GLP-1 and GIP) potentiate insulin secretion through cAMP signaling in pancreatic β-cells in a glucose-dependent manner. We recently proposed a mechanistic model of incretin-induced insulin secretion (IIIS) that requires two critical processes: 1) generation of cytosolic glutamate through the malate-aspartate (MA) shuttle in glucose metabolism and 2) glutamate transport into insulin granules by cAMP signaling to promote insulin granule exocytosis. To directly prove the model, we have established and characterized CRISPR/Cas9-engineered clonal mouse β-cell lines deficient for the genes critical in these two processes: aspartate aminotransferase 1 (AST1, gene symbol Got1), a key enzyme in the MA shuttle, which generates cytosolic glutamate, and the vesicular glutamate transporters (VGLUT1, VGLUT2, and VGLUT3, gene symbol Slc17a7, Slc17a6, and Slc17a8, respectively), which participate in glutamate transport into secretory vesicles. Got1 knockout (KO) β-cell lines were defective in cytosolic glutamate production from glucose and showed impaired IIIS. Unexpectedly, different from the previous finding that global Slc17a7 KO mice exhibited impaired IIIS from pancreatic islets, β-cell specific Slc17a7 KO mice showed no significant impairment in IIIS, as assessed by pancreas perfusion experiment. Single Slc17a7 KO β-cell lines also retained IIIS, probably due to compensatory upregulation of Slc17a6. Interestingly, triple KO of Slc17a7, Slc17a6, and Slc17a8 diminished IIIS, which was rescued by exogenously introduced wild-type Slc17a7 or Slc17a6 genes. The present study provides direct evidence for the essential roles of AST1 and VGLUTs in β-cell glutamate signaling for IIIS and also shows the usefulness of the CRISPR/Cas9 system for studying β-cells by simultaneous disruption of multiple genes.
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Affiliation(s)
- Naoya Murao
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
- * E-mail: (NY); (SS)
| | - Kohei Honda
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Guirong Han
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
- Kansai Electric Power Medical Research Institute, Kobe, Japan
- Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Tomohide Hayami
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
- Kansai Electric Power Medical Research Institute, Kobe, Japan
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, Nagakute, Japan
| | - Ghupurjan Gheni
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohtaro Minami
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
- * E-mail: (NY); (SS)
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20
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Zhang F, Tzanakakis ES. Optogenetic regulation of insulin secretion in pancreatic β-cells. Sci Rep 2017; 7:9357. [PMID: 28839233 PMCID: PMC5571193 DOI: 10.1038/s41598-017-09937-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 08/01/2017] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β-cell insulin production is orchestrated by a complex circuitry involving intracellular elements including cyclic AMP (cAMP). Tackling aberrations in glucose-stimulated insulin release such as in diabetes with pharmacological agents, which boost the secretory capacity of β-cells, is linked to adverse side effects. We hypothesized that a photoactivatable adenylyl cyclase (PAC) can be employed to modulate cAMP in β-cells with light thereby enhancing insulin secretion. To that end, the PAC gene from Beggiatoa (bPAC) was delivered to β-cells. A cAMP increase was noted within 5 minutes of photostimulation and a significant drop at 12 minutes post-illumination. The concomitant augmented insulin secretion was comparable to that from β-cells treated with secretagogues. Greater insulin release was also observed over repeated cycles of photoinduction without adverse effects on viability and proliferation. Furthermore, the expression and activation of bPAC increased cAMP and insulin secretion in murine islets and in β-cell pseudoislets, which displayed a more pronounced light-triggered hormone secretion compared to that of β-cell monolayers. Calcium channel blocking curtailed the enhanced insulin response due to bPAC activity. This optogenetic system with modulation of cAMP and insulin release can be employed for the study of β-cell function and for enabling new therapeutic modalities for diabetes.
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Affiliation(s)
- Fan Zhang
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, USA.
| | - Emmanuel S Tzanakakis
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, USA. .,Clinical and Translational Science Institute, Tufts Medical Center, Boston, MA, 02111, USA.
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21
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Sugawara K, Honda K, Reien Y, Yokoi N, Seki C, Takahashi H, Minami K, Mori I, Matsumoto A, Nakaya H, Seino S. A Novel Diphenylthiosemicarbazide Is a Potential Insulin Secretagogue for Anti-Diabetic Agen. PLoS One 2016; 11:e0164785. [PMID: 27764176 PMCID: PMC5072725 DOI: 10.1371/journal.pone.0164785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/02/2016] [Indexed: 12/20/2022] Open
Abstract
Insulin secretagogues are used for treatment of type 2 diabetes. We attempted to discover novel small molecules to stimulate insulin secretion by using in silico similarity search using sulfonylureas as query, followed by measurement of insulin secretion. Among 38 compounds selected by in silico similarity search, we found three diphenylsemicarbazides and one quinolone that stimulate insulin secretion. We focused on compound 8 (C8), which had the strongest insulin-secreting effect. Based on the structure-activity relationship of C8-derivatives, we identified diphenylthiosemicarbazide (DSC) 108 as the most potent secretagogue. DSC108 increased the intracellular Ca2+ level in MIN6-K8 cells. Competitive inhibition experiment and electrophysiological analysis revealed sulfonylurea receptor 1 (SUR1) to be the target of DSC108 and that this diphenylthiosemicarbazide directly inhibits ATP-sensitive K+ (KATP) channels. Pharmacokinetic analysis showed that DSC108 has a short half-life in vivo. Oral administration of DSC108 significantly suppressed the rises in blood glucose levels after glucose load in wild-type mice and improved glucose tolerance in the Goto-Kakizaki (GK) rat, a model of type 2 diabetes with impaired insulin secretion. Our data indicate that DSC108 is a novel insulin secretagogue, and is a lead compound for development of a new anti-diabetic agent.
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Affiliation(s)
- Kenji Sugawara
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohei Honda
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshie Reien
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Chihiro Seki
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohtaro Minami
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ichiro Mori
- Division of Advance Medical Science, Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Akio Matsumoto
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Haruaki Nakaya
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- * E-mail:
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22
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Yokoi N, Gheni G, Takahashi H, Seino S. β-Cell glutamate signaling: Its role in incretin-induced insulin secretion. J Diabetes Investig 2016; 7 Suppl 1:38-43. [PMID: 27186354 PMCID: PMC4854503 DOI: 10.1111/jdi.12468] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 12/17/2015] [Accepted: 12/21/2015] [Indexed: 11/30/2022] Open
Abstract
Insulin secretion from the pancreatic β-cell (referred to as β-cell hereafter) plays a central role in glucose homeostasis. Impaired insulin secretion is a major factor contributing to the development of diabetes and, therefore, is an important target for treatment of the disease. Cyclic adenosine monophosphate is a key second messenger in β-cells that amplifies insulin secretion. Incretins released by the gut potentiate insulin secretion through cyclic adenosine monophosphate signaling in β-cells, which is the basis for the incretin-based diabetes therapies now being used worldwide. Despite its importance, the interaction between glucose metabolism and incretin/cyclic adenosine monophosphate signaling in β-cells has long been unknown. A recent study showed that cytosolic glutamate produced by glucose metabolism in β-cells is a key signal in incretin-induced insulin secretion. Here we review the physiological and pathophysiological roles of β-cell glutamate signaling in incretin-induced insulin secretion.
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Affiliation(s)
- Norihide Yokoi
- Division of Molecular and Metabolic Medicine Kobe University Graduate School of Medicine Kobe Japan
| | - Ghupurjan Gheni
- Division of Molecular and Metabolic Medicine Kobe University Graduate School of Medicine Kobe Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine Kobe University Graduate School of Medicine Kobe Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine Kobe University Graduate School of Medicine Kobe Japan
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23
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Seino Y, Ogata H, Maekawa R, Izumoto T, Iida A, Harada N, Miki T, Seino S, Inagaki N, Tsunekawa S, Oiso Y, Hamada Y. Fructose induces glucose-dependent insulinotropic polypeptide, glucagon-like peptide-1 and insulin secretion: Role of adenosine triphosphate-sensitive K(+) channels. J Diabetes Investig 2015; 6:522-6. [PMID: 26417408 PMCID: PMC4578490 DOI: 10.1111/jdi.12356] [Citation(s) in RCA: 18] [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: 11/05/2014] [Revised: 02/24/2015] [Accepted: 03/16/2015] [Indexed: 12/25/2022] Open
Abstract
Adenosine triphosphate-sensitive K+ (KATP) channels play an essential role in glucose-induced insulin secretion from pancreatic β-cells. It was recently reported that the KATP channel is also found in the enteroendocrine K-cells and L-cells that secrete glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), respectively. In the present study, we investigated the involvement of the KATP channel in fructose-induced GIP, GLP-1 and insulin secretion in mice. Fructose stimulated GIP secretion, but pretreatment with diazoxide, a KATP channel activator, did not affect fructose-induced GIP secretion under streptozotocin-induced hyperglycemic conditions. Fructose significantly stimulated insulin secretion in Kir6.2+/+ mice, but not in mice lacking KATP channels (Kir6.2−/−), and fructose stimulated GLP-1 secretion in both Kir6.2+/+ mice and Kir6.2−/− mice under the normoglycemic condition. In addition, diazoxide completely blocked fructose-induced insulin secretion in Kir6.2+/+ mice and in MIN6-K8 β-cells. These results show that fructose-induced GIP and GLP-1 secretion is KATP channel-independent and that fructose-induced insulin secretion is KATP channel-dependent.
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Affiliation(s)
- Yusuke Seino
- Department of Metabolic Medicine, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Hidetada Ogata
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Ryuya Maekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Takako Izumoto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Atsushi Iida
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Norio Harada
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Takashi Miki
- Department of Medical Physiology, Graduate School of Medicine, Chiba University Chiba, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine Kobe, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Shin Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Yutaka Oiso
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Yoji Hamada
- Department of Metabolic Medicine, Nagoya University Graduate School of Medicine Nagoya, Japan
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24
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Izumoto-Akita T, Tsunekawa S, Yamamoto A, Uenishi E, Ishikawa K, Ogata H, Iida A, Ikeniwa M, Hosokawa K, Niwa Y, Maekawa R, Yamauchi Y, Seino Y, Hamada Y, Hibi H, Arima H, Ueda M, Oiso Y. Secreted factors from dental pulp stem cells improve glucose intolerance in streptozotocin-induced diabetic mice by increasing pancreatic β-cell function. BMJ Open Diabetes Res Care 2015; 3:e000128. [PMID: 26504525 PMCID: PMC4611480 DOI: 10.1136/bmjdrc-2015-000128] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/25/2015] [Accepted: 09/23/2015] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE Many studies have reported that stem cell transplantation promotes propagation and protection of pancreatic β-cells in streptozotocin (STZ)-induced diabetic mice without the differentiation of transplanted cells into pancreatic β-cells, suggesting that the improvement is due to a paracrine effect of the transplanted cells. We investigated the effects of factors secreted by dental pulp stem cells from human exfoliated deciduous teeth (SHED) on β-cell function and survival. RESEARCH DESIGN AND METHODS Conditioned medium from SHED (SHED-CM) was collected 48 h after culturing in serum-free Dulbecco's modified Eagle's medium (DMEM). The insulin levels in SHED-CM and serum-free conditioned media from human bone marrow-derived mesenchymal stem cells (BM-CM) were undetectable. STZ-induced diabetic male C57B/6J mice were injected with DMEM as a control, SHED-CM, exendin-4 (Ex-4), or BM-CM for 14 days. Mouse pancreatic β-cell line MIN6 cells were incubated with different concentrations of STZ with SHED-CM, DMEM, Ex-4, or BM-CM for 6 h. RESULTS Administration of 1 mL of SHED-CM twice a day improved glucose intolerance in STZ-induced diabetic mice and the effect continued for 20 days after the end of treatment. SHED-CM treatment increased pancreatic insulin content and β-cell mass through proliferation and an intraperitoneal glucose tolerance test revealed enhanced insulin secretion. Incubation of MIN6 cells (a mouse pancreatic β-cell line) with SHED-CM enhanced insulin secretion in a glucose concentration-dependent manner and reduced STZ-induced cell death, indicating that the amelioration of hyperglycemia was caused by the direct effects of SHED-CM on β-cell function and survival. These effects were more pronounced than with the use of Ex-4, a conventional incretin-based drug, and BM-CM, which is a medium derived from other stem cells. CONCLUSIONS These findings suggest that SHED-CM provides direct protection and encourages the propagation of β-cells, and has potential as a novel strategy for treatment of diabetes.
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Affiliation(s)
- Takako Izumoto-Akita
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Shin Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Akihito Yamamoto
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Eita Uenishi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kota Ishikawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hidetada Ogata
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Atsushi Iida
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Makoto Ikeniwa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kaori Hosokawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yasuhiro Niwa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Ryuya Maekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yuichiro Yamauchi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yusuke Seino
- Department of Metabolic Medicine, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yoji Hamada
- Department of Metabolic Medicine, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hideharu Hibi
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Minoru Ueda
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yutaka Oiso
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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25
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Glutamate acts as a key signal linking glucose metabolism to incretin/cAMP action to amplify insulin secretion. Cell Rep 2014; 9:661-73. [PMID: 25373904 PMCID: PMC4536302 DOI: 10.1016/j.celrep.2014.09.030] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 08/19/2014] [Accepted: 09/15/2014] [Indexed: 11/29/2022] Open
Abstract
Incretins, hormones released by the gut after meal ingestion, are essential for maintaining systemic glucose homeostasis by stimulating insulin secretion. The effect of incretins on insulin secretion occurs only at elevated glucose concentrations and is mediated by cAMP signaling, but the mechanism linking glucose metabolism and cAMP action in insulin secretion is unknown. We show here, using a metabolomics-based approach, that cytosolic glutamate derived from the malate-aspartate shuttle upon glucose stimulation underlies the stimulatory effect of incretins and that glutamate uptake into insulin granules mediated by cAMP/PKA signaling amplifies insulin release. Glutamate production is diminished in an incretin-unresponsive, insulin-secreting β cell line and pancreatic islets of animal models of human diabetes and obesity. Conversely, a membrane-permeable glutamate precursor restores amplification of insulin secretion in these models. Thus, cytosolic glutamate represents the elusive link between glucose metabolism and cAMP action in incretin-induced insulin secretion. Glutamate is derived from the malate-aspartate shuttle upon glucose stimulation Shuttle-derived glutamate is crucial for incretin-induced insulin secretion Cytosolic glutamate is transported into insulin granules via cAMP/PKA signaling Glutamate production by glucose is defective in incretin-unresponsive β cells
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26
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Uenishi E, Shibasaki T, Takahashi H, Seki C, Hamaguchi H, Yasuda T, Tatebe M, Oiso Y, Takenawa T, Seino S. Actin dynamics regulated by the balance of neuronal Wiskott-Aldrich syndrome protein (N-WASP) and cofilin activities determines the biphasic response of glucose-induced insulin secretion. J Biol Chem 2013; 288:25851-25864. [PMID: 23867458 DOI: 10.1074/jbc.m113.464420] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actin dynamics in pancreatic β-cells is involved in insulin secretion. However, the molecular mechanisms of the regulation of actin dynamics by intracellular signals in pancreatic β-cells and its role in phasic insulin secretion are largely unknown. In this study, we elucidate the regulation of actin dynamics by neuronal Wiskott-Aldrich syndrome protein (N-WASP) and cofilin in pancreatic β-cells and demonstrate its role in glucose-induced insulin secretion (GIIS). N-WASP, which promotes actin polymerization through activation of the actin nucleation factor Arp2/3 complex, was found to be activated by glucose stimulation in insulin-secreting clonal pancreatic β-cells (MIN6-K8 β-cells). Introduction of a dominant-negative mutant of N-WASP, which lacks G-actin and Arp2/3 complex-binding region VCA, into MIN6-K8 β-cells or knockdown of N-WASP suppressed GIIS, especially the second phase. We also found that cofilin, which severs F-actin in its dephosphorylated (active) form, is converted to the phosphorylated (inactive) form by glucose stimulation in MIN6-K8 β-cells, thereby promoting F-actin remodeling. In addition, the dominant-negative mutant of cofilin, which inhibits activation of endogenous cofilin, or knockdown of cofilin reduced the second phase of GIIS. However, the first phase of GIIS occurs in the G-actin predominant state, in which cofilin activity predominates over N-WASP activity. Thus, actin dynamics regulated by the balance of N-WASP and cofilin activities determines the biphasic response of GIIS.
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Affiliation(s)
- Eita Uenishi
- From the Division of Cellular and Molecular Medicine,; the Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya 466-8550, and
| | | | | | - Chihiro Seki
- From the Division of Cellular and Molecular Medicine
| | | | - Takao Yasuda
- From the Division of Cellular and Molecular Medicine
| | - Masao Tatebe
- From the Division of Cellular and Molecular Medicine
| | - Yutaka Oiso
- the Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya 466-8550, and
| | - Tadaomi Takenawa
- Division of Lipid Biochemistry, and; the Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medicine, Kobe 650-0017
| | - Susumu Seino
- From the Division of Cellular and Molecular Medicine,; the Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medicine, Kobe 650-0017,; Division of Molecular and Metabolic Medicine,; the Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corp., Kawaguchi, Saitama 332-0012, Japan.
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27
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Seino S, Shibasaki T, Minami K. Dynamics of insulin secretion and the clinical implications for obesity and diabetes. J Clin Invest 2011; 121:2118-25. [PMID: 21633180 DOI: 10.1172/jci45680] [Citation(s) in RCA: 250] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Insulin secretion is a highly dynamic process regulated by various factors including nutrients, hormones, and neuronal inputs. The dynamics of insulin secretion can be studied at different levels: the single β cell, pancreatic islet, whole pancreas, and the intact organism. Studies have begun to analyze cellular and molecular mechanisms underlying dynamics of insulin secretion. This review focuses on our current understanding of the dynamics of insulin secretion in vitro and in vivo and discusses their clinical relevance.
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Affiliation(s)
- Susumu Seino
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
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