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Tamayo A, Gonçalves LM, Rodriguez-Diaz R, Pereira E, Canales M, Caicedo A, Almaça J. Pericyte Control of Blood Flow in Intraocular Islet Grafts Impacts Glucose Homeostasis in Mice. Diabetes 2022; 71:1679-1693. [PMID: 35587617 PMCID: PMC9490358 DOI: 10.2337/db21-1104] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/19/2022] [Indexed: 11/13/2022]
Abstract
The pancreatic islet depends on blood supply to efficiently sense plasma glucose levels and deliver insulin and glucagon into the circulation. Long believed to be passive conduits of nutrients and hormones, islet capillaries were recently found to be densely covered with contractile pericytes with the capacity to locally control blood flow. Here, we determined the contribution of pericyte regulation of islet blood flow to plasma insulin and glucagon levels and glycemia. Selective optogenetic activation of pericytes in intraocular islet grafts contracted capillaries and diminished blood flow. In awake mice, acute light-induced stimulation of islet pericytes decreased insulin and increased glucagon plasma levels, producing hyperglycemic effects. Interestingly, pericytes are the targets of sympathetic nerves in the islet, suggesting that sympathetic control of hormone secretion may occur in part by modulating pericyte activity and blood flow. Indeed, in vivo activation of pericytes with the sympathetic agonist phenylephrine decreased blood flow in mouse islet grafts, lowered plasma insulin levels, and increased glycemia. We further show that islet pericytes and blood vessels in living human pancreas slices responded to sympathetic input. Our findings indicate that pericytes mediate vascular responses in the islet that are required for adequate hormone secretion and glucose homeostasis. Vascular and neuronal alterations that are commonly seen in the islets of people with diabetes may impair regulation of islet blood flow and thus precipitate islet dysfunction.
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Affiliation(s)
- Alejandro Tamayo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Luciana Mateus Gonçalves
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Rayner Rodriguez-Diaz
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Elizabeth Pereira
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL
| | - Melissa Canales
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Program of Neuroscience, University of Miami Miller School of Medicine, Miami, FL
| | - Joana Almaça
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
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Michau A, Lafont C, Bargi-Souza P, Kemkem Y, Guillou A, Ravier MA, Bertrand G, Varrault A, Fiordelisio T, Hodson DJ, Mollard P, Schaeffer M. Metabolic Stress Impairs Pericyte Response to Optogenetic Stimulation in Pancreatic Islets. Front Endocrinol (Lausanne) 2022; 13:918733. [PMID: 35813647 PMCID: PMC9259887 DOI: 10.3389/fendo.2022.918733] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 04/12/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Pancreatic islets are highly vascularized micro-organs ensuring whole body glucose homeostasis. Islet vascular cells play an integral part in sustaining adequate insulin release by beta cells. In particular, recent studies have demonstrated that islet pericytes regulate local blood flow velocity and are required for maintenance of beta cell maturity and function. In addition, increased metabolic demand accompanying obesity alters islet pericyte morphology. Here, we sought to explore the effects of metabolic stress on islet pericyte functional response to stimulation in a mouse model of type 2 diabetes, directly in the pancreas in vivo . We found that high fat diet induced islet pericyte hypertrophy without alterations in basal local blood flow. However, optogenetic stimulation of pericyte activity revealed impaired islet vascular responses, despite increased expression of genes encoding proteins directly or indirectly involved in cell contraction. These findings suggest that metabolic stress impinges upon islet pericyte function, which may contribute to beta cell failure during T2D.
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Affiliation(s)
- Aurélien Michau
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Chrystel Lafont
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Paula Bargi-Souza
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
- Department of Physiology and Biophysics of the Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Yasmine Kemkem
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Anne Guillou
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Magalie A. Ravier
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Gyslaine Bertrand
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Annie Varrault
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Tatiana Fiordelisio
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
- Laboratorio de Neuroendocrinología Comparada, Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - David J. Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), National Institute for Health and Care Research (NIHR) Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Patrice Mollard
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Marie Schaeffer
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France
- *Correspondence: Marie Schaeffer,
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Ng XW, Chung YH, Piston DW. Intercellular Communication in the Islet of Langerhans in Health and Disease. Compr Physiol 2021; 11:2191-2225. [PMID: 34190340 DOI: 10.1002/cphy.c200026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon, and somatostatin from the β-, α-, and δ-cells, respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca2+ activity, as well as the two-phase insulin secretion profile, are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and nonhormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this article, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types. © 2021 American Physiological Society. Compr Physiol 11:2191-2225, 2021.
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Affiliation(s)
- Xue W Ng
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - Yong H Chung
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
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The Connexin 43 Regulator Rotigaptide Reduces Cytokine-Induced Cell Death in Human Islets. Int J Mol Sci 2020; 21:ijms21124311. [PMID: 32560352 PMCID: PMC7352593 DOI: 10.3390/ijms21124311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 01/23/2023] Open
Abstract
Background: Intercellular communication mediated by cationic fluxes through the Connexin family of gap junctions regulates glucose-stimulated insulin secretion and beta cell defense against inflammatory stress. Rotigaptide (RG, ZP123) is a peptide analog that increases intercellular conductance in cardiac muscle cells by the prevention of dephosphorylation and thereby uncoupling of Connexin-43 (Cx43), possibly via action on unidentified protein phosphatases. For this reason, it is being studied in human arrhythmias. It is unknown if RG protects islet cell function and viability against inflammatory or metabolic stress, a question of considerable translational interest for the treatment of diabetes. Methods: Apoptosis was measured in human islets shown to express Cx43, treated with RG or the control peptide ZP119 and exposed to glucolipotoxicity or IL-1β + IFNɣ. INS-1 cells shown to lack Cx43 were used to examine if RG protected human islet cells via Cx43 coupling. To study the mechanisms of action of Cx43-independent effects of RG, NO, IkBα degradation, mitochondrial activity, ROS, and insulin mRNA levels were determined. Results: RG reduced cytokine-induced apoptosis ~40% in human islets. In Cx43-deficient INS-1 cells, this protective effect was markedly blunted as expected, but unexpectedly, RG still modestly reduced apoptosis, and improved mitochondrial function, insulin-2 gene levels, and accumulated insulin release. RG reduced NO production in Cx43-deficient INS-1 cells associated with reduced iNOS expression, suggesting that RG blunts cytokine-induced NF-κB signaling in insulin-producing cells in a Cx43-independent manner. Conclusion: RG reduces cytokine-induced cell death in human islets. The protective action in Cx43-deficient INS-1 cells suggests a novel inhibitory mechanism of action of RG on NF-κB signaling.
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Jansson L, Carlsson PO. Pancreatic Blood Flow with Special Emphasis on Blood Perfusion of the Islets of Langerhans. Compr Physiol 2019; 9:799-837. [PMID: 30892693 DOI: 10.1002/cphy.c160050] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The pancreatic islets are more richly vascularized than the exocrine pancreas, and possess a 5- to 10-fold higher basal and stimulated blood flow, which is separately regulated. This is reflected in the vascular anatomy of the pancreas where islets have separate arterioles. There is also an insulo-acinar portal system, where numerous venules connect each islet to the acinar capillaries. Both islets and acini possess strong metabolic regulation of their blood perfusion. Of particular importance, especially in the islets, is adenosine and ATP/ADP. Basal and stimulated blood flow is modified by local endothelial mediators, the nervous system as well as gastrointestinal hormones. Normally the responses to the nervous system, especially the parasympathetic and sympathetic nerves, are fairly similar in endocrine and exocrine parts. The islets seem to be more sensitive to the effects of endothelial mediators, especially nitric oxide, which is a permissive factor to maintain the high basal islet blood flow. The gastrointestinal hormones with pancreatic effects mainly influence the exocrine pancreatic blood flow, whereas islets are less affected. A notable exception is incretin hormones and adipokines, which preferentially affect islet vasculature. Islet hormones can influence both exocrine and endocrine blood vessels, and these complex effects are discussed. Secondary changes in pancreatic and islet blood flow occur during several conditions. To what extent changes in blood perfusion may affect the pathogenesis of pancreatic diseases is discussed. Both type 2 diabetes mellitus and acute pancreatitis are conditions where we think there is evidence that blood flow may contribute to disease manifestations. © 2019 American Physiological Society. Compr Physiol 9:799-837, 2019.
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Affiliation(s)
- Leif Jansson
- Uppsala University, Department of Medical Cell Biology, Uppsala, Sweden
| | - Per-Ola Carlsson
- Uppsala University, Department of Medical Cell Biology, Uppsala, Sweden.,Uppsala University, Department of Medical Sciences, Uppsala, Sweden
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Almaça J, Weitz J, Rodriguez-Diaz R, Pereira E, Caicedo A. The Pericyte of the Pancreatic Islet Regulates Capillary Diameter and Local Blood Flow. Cell Metab 2018; 27:630-644.e4. [PMID: 29514070 PMCID: PMC5876933 DOI: 10.1016/j.cmet.2018.02.016] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/15/2017] [Accepted: 02/15/2018] [Indexed: 12/20/2022]
Abstract
Efficient insulin secretion requires a well-functioning pancreatic islet microvasculature. The dense network of islet capillaries includes the islet pericyte, a cell that has barely been studied. Here we show that islet pericytes help control local blood flow by adjusting islet capillary diameter. Islet pericytes cover 40% of the microvasculature, are contractile, and are innervated by sympathetic axons. Sympathetic adrenergic input increases pericyte activity and reduces capillary diameter and local blood flow. By contrast, activating beta cells by increasing glucose concentration inhibits pericytes, dilates islet capillaries, and increases local blood flow. These effects on pericytes are mediated by endogenous adenosine, which is likely derived from ATP co-released with insulin. Pericyte coverage of islet capillaries drops drastically in type 2 diabetes, suggesting that, under diabetic conditions, islets lose this mechanism to control their own blood supply. This may lead to inadequate insulin release into the circulation, further deteriorating glycemic control.
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Affiliation(s)
- Joana Almaça
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Jonathan Weitz
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Molecular Cell and Developmental Biology Program, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Rayner Rodriguez-Diaz
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Elizabeth Pereira
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Program in Neuroscience, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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Umrani MR, Joglekar MV, Somerville Glover E, Wong W, Hardikar AA. Connexins and microRNAs: Interlinked players in regulating islet function? Islets 2017; 9:99-108. [PMID: 28686518 PMCID: PMC5624287 DOI: 10.1080/19382014.2017.1331192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 02/09/2023] Open
Abstract
Pancreatic β-cells are connected to neighboring endocrine cells through the adherin proteins and gap junctions. Connexin 36 (Cx36) is one of the most well-studied and abundantly expressed gap-junction proteins within rodent islets, which is important in coordinated insulin secretion. The expression of connexins is regulated at various levels and by several mechanisms; one of which is via microRNAs. In past 2 decades, microRNAs (miRNAs) have emerged as key molecules in developmental, physiologic and pathological processes. However, very few studies have demonstrated miRNA-mediated regulation of connexins. Even though there are no reports yet on miRNAs and Cx36; we envisage that considering the important role of connexins and microRNAs in insulin secretion, there would be common pathways interlinking these biomolecules. Here, we discuss the current literature on connexins and miRNAs specifically with reference to islet function.
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Affiliation(s)
- Malati R. Umrani
- National centre for cell science, Ganeshkhind, Pune University Campus, Pune, India
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Mugdha V. Joglekar
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Ella Somerville Glover
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Wilson Wong
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Anandwardhan A. Hardikar
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
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8
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Abstract
The pancreas produces enzymes with a digestive function and hormones with a metabolic function, which are produced by distinct cell types of acini and islets, respectively. Within these units, secretory cells coordinate their functioning by exchanging information via signals that flow in the intercellular spaces and are generated either at distance (several neural and hormonal inputs) or nearby the pancreatic cells themselves (inputs mediated by membrane ionic-specific channels and by ionic- and metabolite-permeant pannexin channels and connexin "hemichannels"). Pancreatic secretory cells further interact via the extracellular matrix of the pancreas (inputs mediated by integrins) and directly with neighboring cells, by mechanisms that do not require extracellular mediators (inputs mediated by gap and tight junction channels). Here, we review the expression and function of the connexins and pannexins that are expressed by the main secretory cells of the exocrine and endocrine pancreatic cells. Available data show that the patterns of expression of these proteins differ in acini and islets, supporting distinct functions in the physiological secretion of pancreatic enzymes and hormones. Circumstantial evidence further suggests that alterations in the signaling provided by these proteins are involved in pancreatic diseases.
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Yang L, Yin N, Hu L, Fan H, Yu D, Zhang W, Wang S, Feng Y, Fan C, Cao F, Mo X. Sildenefil increases connexin 40 in smooth muscle cells through activation of BMP pathways in pulmonary arterial hypertension. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:4674-84. [PMID: 25197339 PMCID: PMC4152029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/02/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a cardiovascular disorder associated with enhanced proliferation and suppressed apoptosis of pulmonary arterial smooth muscle cells (PASMCs). The sildenafil can regulate the Connexin (Cx) 43 in the PASMCs and thus inhibit the PASMCs proliferation and the remodeling of pulmonary arterial. However, how sildenafil exert regulation in the Cx40 in the PASMCs in PAH remains unclear. METHODS AND RESULTS Using the rat PAH model induced by the monocrotoline, we demonstrated that the Cx40 in the PASMCs is down-regulated in the PAH. The sildenafil promotes the up-regulation of Cx40 in the PASMCs via bone morphogenetic protein (BMP) signaling, accompanied by an anti-proliferative response in PASMCs. Inhibition of the BMP axis reverses the up-regulation of Cx40 and anti-proliferation of the sildenafil in these cells. In monocrotaline-induced PAH rat models, which display reduced levels of BMP signaling, this study further indicates that the BMP-Cx40 axis is activated in lungs following the sildenafil treatment. Furthermore, we also find in vitro that sildenafil increases the Cx40 expression of PASMCs isolated from MCT-PAH rats and inhibit the proliferation of these cells. These phenomenon are reversed by LDN-193189, the antagonist of type II receptor for bone morphogenetic protein (BMPR2) treatment, providing strong evidence for the protect effect of sildenafil and the BMP-Cx40 axis involvement. CONCLUSIONS Taken together, these data suggest the sildenafil activate BMP-Cx40 signaling in the PAH. This axis may be a potential therapeutic target in PAH.
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MESH Headings
- Animals
- Blotting, Western
- Bone Morphogenetic Proteins/metabolism
- Connexins/biosynthesis
- Disease Models, Animal
- Hypertension, Pulmonary/metabolism
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Piperazines/pharmacology
- Purines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Real-Time Polymerase Chain Reaction
- Signal Transduction/drug effects
- Sildenafil Citrate
- Sulfonamides/pharmacology
- Vascular Remodeling/drug effects
- Vasodilator Agents/pharmacology
- Gap Junction alpha-5 Protein
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Affiliation(s)
- Lei Yang
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Ning Yin
- Department of Anesthesiology, Zhongda Hospital Southeast University Nanjing, China
| | - Liang Hu
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Huanhuan Fan
- Department of Gynecology, Jiangsu Province Hospital of TCM Nanjing, China
| | - Di Yu
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Weiyan Zhang
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Song Wang
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Yu Feng
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Changfeng Fan
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Fang Cao
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
| | - Xuming Mo
- Department of Cardiothoracic Surgery, Nanjing Children's Hospital Affiliated of Nanjing Medical University Nanjing, China
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Farnsworth NL, Benninger RKP. New insights into the role of connexins in pancreatic islet function and diabetes. FEBS Lett 2014; 588:1278-87. [PMID: 24583073 DOI: 10.1016/j.febslet.2014.02.035] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 02/13/2014] [Accepted: 02/19/2014] [Indexed: 12/22/2022]
Abstract
Multi-cellular systems require complex signaling mechanisms for proper tissue function, to mediate signaling between cells in close proximity and at distances. This holds true for the islets of Langerhans, which are multicellular micro-organs located in the pancreas responsible for glycemic control, through secretion of insulin and other hormones. Coupling of electrical and metabolic signaling between islet β-cells is required for proper insulin secretion and effective glycemic control. β-cell specific coupling is established through gap junctions composed of connexin36, which results in coordinated insulin release across the islet. Islet connexins have been implicated in both Type-1 and Type-2 diabetes; however a clear link remains to be determined. The goal of this review is to discuss recent discoveries regarding the role of connexins in regulating insulin secretion, the regulation of connexins within the islet, and recent studies which support a role for connexins in diabetes. Further studies which investigate the regulation of connexins in the islet and their role in diabetes may lead to novel diabetes therapies which regulate islet function and β-cell survival through modulation of gap junction coupling.
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Affiliation(s)
- Nikki L Farnsworth
- Barbara Davis center for childhood diabetes, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, United States
| | - Richard K P Benninger
- Barbara Davis center for childhood diabetes, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, United States; Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, United States.
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