1
|
Cottle L, Gan WJ, Gilroy I, Samra JS, Gill AJ, Loudovaris T, Thomas HE, Hawthorne WJ, Kebede MA, Thorn P. Structural and functional polarisation of human pancreatic beta cells in islets from organ donors with and without type 2 diabetes. Diabetologia 2021; 64:618-629. [PMID: 33399909 PMCID: PMC7864831 DOI: 10.1007/s00125-020-05345-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/09/2020] [Indexed: 12/05/2022]
Abstract
AIMS/HYPOTHESIS We hypothesised that human beta cells are structurally and functional polarised with respect to the islet capillaries. We set out to test this using confocal microscopy to map the 3D spatial arrangement of key proteins and live-cell imaging to determine the distribution of insulin granule fusion around the cells. METHODS Human pancreas samples were rapidly fixed and processed using the pancreatic slice technique, which maintains islet structure and architecture. Slices were stained using immunofluorescence for polarity markers (scribble, discs large [Dlg] and partitioning defective 3 homologue [Par3]) and presynaptic markers (liprin, Rab3-interacting protein [RIM2] and piccolo) and imaged using 3D confocal microscopy. Isolated human islets were dispersed and cultured on laminin-511-coated coverslips. Live 3D two-photon microscopy was used on cultured cells to image exocytic granule fusion events upon glucose stimulation. RESULTS Assessment of the distribution of endocrine cells across human islets found that, despite distinct islet-to-islet complexity and variability, including multi-lobular islets, and intermixing of alpha and beta cells, there is still a striking enrichment of alpha cells at the islet mantle. Measures of cell position demonstrate that most beta cells contact islet capillaries. Subcellularly, beta cells consistently position polar determinants, such as Par3, Dlg and scribble, with a basal domain towards the capillaries and apical domain at the opposite face. The capillary interface/vascular face is enriched in presynaptic scaffold proteins, such as liprin, RIM2 and piccolo. Interestingly, enrichment of presynaptic scaffold proteins also occurs where the beta cells contact peri-islet capillaries, suggesting functional interactions. We also observed the same polarisation of synaptic scaffold proteins in islets from type 2 diabetic patients. Consistent with polarised function, isolated beta cells cultured onto laminin-coated coverslips target insulin granule fusion to the coverslip. CONCLUSIONS/INTERPRETATION Structural and functional polarisation is a defining feature of human pancreatic beta cells and plays an important role in the control of insulin secretion.
Collapse
Affiliation(s)
- Louise Cottle
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Wan Jun Gan
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
- Temasek Life-Science Laboratory, Singapore, Republic of Singapore
| | - Ian Gilroy
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Jaswinder S Samra
- The University of Sydney Northern Clinical School, Sydney, NSW, Australia
- Upper Gastrointestinal Surgical Unit, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Anthony J Gill
- The University of Sydney Northern Clinical School, Sydney, NSW, Australia
- Department of Anatomical Pathology, Royal North Shore Hospital, St Leonards, NSW, Australia
- Cancer Diagnosis and Pathology Research Group, Kolling Institute of Medical Research, St Leonards, NSW, Australia
| | | | - Helen E Thomas
- St Vincent's Institute, Fitzroy, VIC, Australia
- The University of Melbourne, Department of Medicine, St Vincent's Hospital, Fitzroy, VIC, Australia
| | - Wayne J Hawthorne
- Centre for Transplant and Renal Research, Westmead Hospital, Sydney, NSW, Australia
- Westmead Clinical School, Faculty of Health and Medicine, University of Sydney, Sydney, Australia
| | - Melkam A Kebede
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Peter Thorn
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia.
| |
Collapse
|
2
|
Farino ZJ, Morgenstern TJ, Maffei A, Quick M, De Solis AJ, Wiriyasermkul P, Freyberg RJ, Aslanoglou D, Sorisio D, Inbar BP, Free RB, Donthamsetti P, Mosharov EV, Kellendonk C, Schwartz GJ, Sibley DR, Schmauss C, Zeltser LM, Moore H, Harris PE, Javitch JA, Freyberg Z. New roles for dopamine D 2 and D 3 receptors in pancreatic beta cell insulin secretion. Mol Psychiatry 2020; 25:2070-2085. [PMID: 30626912 PMCID: PMC6616020 DOI: 10.1038/s41380-018-0344-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/17/2018] [Accepted: 12/10/2018] [Indexed: 01/11/2023]
Abstract
Although long-studied in the central nervous system, there is increasing evidence that dopamine (DA) has important roles in the periphery including in metabolic regulation. Insulin-secreting pancreatic β-cells express the machinery for DA synthesis and catabolism, as well as all five DA receptors. In these cells, DA functions as a negative regulator of glucose-stimulated insulin secretion (GSIS), which is mediated by DA D2-like receptors including D2 (D2R) and D3 (D3R) receptors. However, the fundamental mechanisms of DA synthesis, storage, release, and signaling in pancreatic β-cells and their functional relevance in vivo remain poorly understood. Here, we assessed the roles of the DA precursor L-DOPA in β-cell DA synthesis and release in conjunction with the signaling mechanisms underlying DA's inhibition of GSIS. Our results show that the uptake of L-DOPA is essential for establishing intracellular DA stores in β-cells. Glucose stimulation significantly enhances L-DOPA uptake, leading to increased DA release and GSIS reduction in an autocrine/paracrine manner. Furthermore, D2R and D3R act in combination to mediate dopaminergic inhibition of GSIS. Transgenic knockout mice in which β-cell D2R or D3R expression is eliminated exhibit diminished DA secretion during glucose stimulation, suggesting a new mechanism where D2-like receptors modify DA release to modulate GSIS. Lastly, β-cell-selective D2R knockout mice exhibit marked postprandial hyperinsulinemia in vivo. These results reveal that peripheral D2R and D3R receptors play important roles in metabolism through their inhibitory effects on GSIS. This opens the possibility that blockade of peripheral D2-like receptors by drugs including antipsychotic medications may significantly contribute to the metabolic disturbances observed clinically.
Collapse
Affiliation(s)
- Zachary J. Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Travis J. Morgenstern
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Antonella Maffei
- Division of Endocrinology, Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Matthias Quick
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Alain J. De Solis
- Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University, New York, NY, USA
| | - Pattama Wiriyasermkul
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Current address: Department of Collaborative Research, Nara Medical University, Kashihara, Nara, Japan
| | - Robin J. Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Denise Sorisio
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Benjamin P. Inbar
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - R. Benjamin Free
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Prashant Donthamsetti
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Current address: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Eugene V. Mosharov
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Neurology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Christoph Kellendonk
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Pharmacology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Gary J. Schwartz
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Claudia Schmauss
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Lori M. Zeltser
- Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University, New York, NY, USA,Department of Pathology and Cell Biology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Holly Moore
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY, USA
| | - Paul E. Harris
- Division of Endocrinology, Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Jonathan A. Javitch
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Pharmacology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.
| |
Collapse
|
3
|
Hastoy B, Clark A, Rorsman P, Lang J. Fusion pore in exocytosis: More than an exit gate? A β-cell perspective. Cell Calcium 2017; 68:45-61. [PMID: 29129207 DOI: 10.1016/j.ceca.2017.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/17/2017] [Accepted: 10/24/2017] [Indexed: 12/14/2022]
Abstract
Secretory vesicle exocytosis is a fundamental biological event and the process by which hormones (like insulin) are released into the blood. Considerable progress has been made in understanding this precisely orchestrated sequence of events from secretory vesicle docked at the cell membrane, hemifusion, to the opening of a membrane fusion pore. The exact biophysical and physiological regulation of these events implies a close interaction between membrane proteins and lipids in a confined space and constrained geometry to ensure appropriate delivery of cargo. We consider some of the still open questions such as the nature of the initiation of the fusion pore, the structure and the role of the Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor (SNARE) transmembrane domains and their influence on the dynamics and regulation of exocytosis. We discuss how the membrane composition and protein-lipid interactions influence the likelihood of the nascent fusion pore forming. We relate these factors to the hypothesis that fusion pore expansion could be affected in type-2 diabetes via changes in disease-related gene transcription and alterations in the circulating lipid profile. Detailed characterisation of the dynamics of the fusion pore in vitro will contribute to understanding the larger issue of insulin secretory defects in diabetes.
Collapse
Affiliation(s)
- Benoit Hastoy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK.
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK; Metabolic Research, Institute of Neuroscience and Physiology, University of Goteborg, Medicinaregatan 11, S-41309 Göteborg, Sweden
| | - Jochen Lang
- Laboratoire de Chimie et Biologie des Membranes et Nano-objets (CBMN), CNRS UMR 5248, Université de Bordeaux, Allée de Geoffrey St Hilaire, 33600 Pessac, France.
| |
Collapse
|
4
|
Li Y, Li F, Bai B, Wu Z, Hou X, Shen Y, Wang Y. Protein interacting with C‑kinase 1 modulates exocytosis and KATP conductance in pancreatic β cells. Mol Med Rep 2017; 16:4247-4252. [PMID: 28731156 DOI: 10.3892/mmr.2017.7056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 04/06/2017] [Indexed: 11/06/2022] Open
Abstract
It has been previously identified that α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors (AMPARs) are expressed in pancreatic β cells and regulate exocytosis and insulin release. It is known that protein interacting with C‑kinase 1 (PICK1) regulates trafficking and synaptic targeting of AMPARs in the central nervous system. However, it is unknown whether PICK1 regulates glutamate‑induced insulin release in β cells. The present study demonstrated that glutamate‑induced exocytosis was increased in β cells derived from PICK1‑knockout mice. In agreement with this result, adding PICK1 in β cells reduced glutamate‑induced exocytosis, whereas adding EVKI, a peptide that interrupts the interaction between AMPARs and PICK1, increased the exocytosis of β cells with the application of glutamate. Furthermore, the conductance of ATP‑sensitive potassium (KATP) channels was reduced in PICK1‑knockout mice, which was reversed by the overexpression of PICK1. In addition, PICK1 application reduced voltage oscillation induced by the closure of KATP. Taken together, the results indicate that PICK1 regulates glutamate‑induced exocytosis in β cells.
Collapse
Affiliation(s)
- Yunhong Li
- Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Basic Medical College of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Fan Li
- Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Basic Medical College of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Bin Bai
- Department of Endocrinology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Zhenyong Wu
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Xiaolin Hou
- Department of Endocrinology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Ying Shen
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Yin Wang
- Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Basic Medical College of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| |
Collapse
|
5
|
Mosedale M, Egodage S, Calma RC, Chi NW, Chessler SD. Neurexin-1α contributes to insulin-containing secretory granule docking. J Biol Chem 2012; 287:6350-61. [PMID: 22235116 DOI: 10.1074/jbc.m111.299081] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Neurexins are a family of transmembrane, synaptic adhesion molecules. In neurons, neurexins bind to both sub-plasma membrane and synaptic vesicle-associated constituents of the secretory machinery, play a key role in the organization and stabilization of the presynaptic active zone, and help mediate docking of synaptic vesicles. We have previously shown that neurexins, like many other protein constituents of the neurotransmitter exocytotic machinery, are expressed in pancreatic β cells. We hypothesized that the role of neurexins in β cells parallels their role in neurons, with β-cell neurexins helping to mediate insulin granule docking and secretion. Here we demonstrate that β cells express a more restricted pattern of neurexin transcripts than neurons, with a clear predominance of neurexin-1α expressed in isolated islets. Using INS-1E β cells, we found that neurexin-1α interacts with membrane-bound components of the secretory granule-docking machinery and with the granule-associated protein granuphilin. Decreased expression of neurexin-1α, like decreased expression of granuphilin, reduces granule docking at the β-cell membrane and improves insulin secretion. Perifusion of neurexin-1α KO mouse islets revealed a significant increase in second-phase insulin secretion with a trend toward increased first-phase secretion. Upon glucose stimulation, neurexin-1α protein levels decrease. This glucose-induced down-regulation may enhance glucose-stimulated insulin secretion. We conclude that neurexin-1α is a component of the β-cell secretory machinery and contributes to secretory granule docking, most likely through interactions with granuphilin. Neurexin-1α is the only transmembrane component of the docking machinery identified thus far. Our findings provide new insights into the mechanisms of insulin granule docking and exocytosis.
Collapse
Affiliation(s)
- Merrie Mosedale
- Pediatric Diabetes Research Center, Veterans Affairs San Diego Healthcare System, University of California San Diego, La Jolla, California 92093, USA
| | | | | | | | | |
Collapse
|