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Abstract
This review focuses on the human pancreatic islet-including its structure, cell composition, development, function, and dysfunction. After providing a historical timeline of key discoveries about human islets over the past century, we describe new research approaches and technologies that are being used to study human islets and how these are providing insight into human islet physiology and pathophysiology. We also describe changes or adaptations in human islets in response to physiologic challenges such as pregnancy, aging, and insulin resistance and discuss islet changes in human diabetes of many forms. We outline current and future interventions being developed to protect, restore, or replace human islets. The review also highlights unresolved questions about human islets and proposes areas where additional research on human islets is needed.
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Affiliation(s)
- John T Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Diane C Saunders
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Marcela Brissova
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.,Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,VA Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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2
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Flatt AJS, Greenbaum CJ, Shaw JAM, Rickels MR. Pancreatic islet reserve in type 1 diabetes. Ann N Y Acad Sci 2021; 1495:40-54. [PMID: 33550589 DOI: 10.1111/nyas.14572] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/18/2021] [Accepted: 01/21/2021] [Indexed: 12/22/2022]
Abstract
Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by pancreatic islet β cell loss and dysfunction resulting in insulin deficiency and hyperglycemia. During a presymptomatic phase of established β cell autoimmunity, β cell loss may first be evident through assessment of β cell secretory capacity, a measure of functional β cell mass. Reduction in pancreatic islet β cell reserve eventually manifests as impaired first-phase insulin response to glucose and abnormal glucose tolerance, which progresses until the functional capacity for β cell secretion can no longer meet the demand for insulin to control glycemia. A functional β cell mass of ∼25% of normal may be required to avoid symptomatic T1D but is already associated with dysregulated glucagon secretion. With symptomatic T1D, stimulated C-peptide levels >0.60 ng/mL (0.200 pmol/mL) indicate the presence of clinically meaningful residual β cell function for contributing to glycemic control, although even higher residual C-peptide appears necessary for evidencing glucose-dependent islet β and α cell function that may contribute to maintaining (near)normal glycemia. β cell replacement by islet transplantation can restore a physiologic reserve capacity for insulin secretion, confirming thresholds for functional β cell mass required for independence from insulin therapy.
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Affiliation(s)
- Anneliese J S Flatt
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,Institute of Transplantation, Freeman Hospital, Newcastle upon Tyne, UK
| | - Carla J Greenbaum
- Diabetes Program and Center for Interventional Immunology, Benaroya Research Institute, Seattle, Washington
| | - James A M Shaw
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,Institute of Transplantation, Freeman Hospital, Newcastle upon Tyne, UK
| | - Michael R Rickels
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.,Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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3
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Tanday N, Irwin N, Moffett RC, Flatt PR, O'Harte FPM. Beneficial actions of a long-acting apelin analogue in diabetes are related to positive effects on islet cell turnover and transdifferentiation. Diabetes Obes Metab 2020; 22:2468-2478. [PMID: 32844576 DOI: 10.1111/dom.14177] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/10/2020] [Accepted: 08/23/2020] [Indexed: 12/19/2022]
Abstract
AIM The current study has tested the hypothesis that the positive effects of apelin receptor activation in diabetes are linked to benefits on islet cell apoptosis, proliferation and transdifferentiation using Ins1Cre/+ ;Rosa26-eYFP transgenic mice and induction of diabetes-like syndromes by streptozotocin (STZ) or high-fat feeding. MATERIALS AND METHODS Groups (n = 6-8) of streptozotocin (STZ)-induced diabetic and high-fat diet (HFD)-fed mice received once-daily injection (25 nmol/kg) of the long-acting acylated apelin-13 analogue, pGlu(Lys8 Glu-PAL)apelin-13 amide, for 10 or 12 days, respectively. RESULTS pGlu(Lys8 Glu-PAL)apelin-13 amide treatment partly reversed body weight loss induced by STZ and normalized circulating insulin. There was no effect of pGlu(Lys8 Glu-PAL)apelin-13 amide on these variables in HFD-fed mice, but an increase in pancreatic insulin content was observed. pGlu(Lys8 Glu-PAL)apelin-13 amide also fully, or partially, reversed the detrimental effects of STZ and HFD on plasma and pancreatic glucagon concentrations. In HFD-fed mice, the apelin analogue decreased dietary-induced elevations of islet, β- and α-cell areas, whilst reducing α-cell area in STZ-induced diabetic mice. In terms of islet cell lineage, pGlu(Lys8 Glu-PAL)apelin-13 amide effectively reduced β- to α-cell transdifferentiation and helped maintain β-cell identity, which was linked to elevated Pdx-1 expression. These islet effects were coupled with decreased β-cell apoptosis and α-cell proliferation in both models, and there was an accompanying increase of β-cell proliferation in STZ-induced diabetic mice. CONCLUSION Taken together these data demonstrate, for the first time, that pancreatic islet benefits of sustained APJ receptor activation in diabetes are linked to favourable islet cell transition events, leading to maintenance of β-cell mass.
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Affiliation(s)
- Neil Tanday
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - R Charlotte Moffett
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Finbarr P M O'Harte
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
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4
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Viloria K, Nasteska D, Briant LJB, Heising S, Larner DP, Fine NHF, Ashford FB, da Silva Xavier G, Ramos MJ, Hasib A, Cuozzo F, Manning Fox JE, MacDonald PE, Akerman I, Lavery GG, Flaxman C, Morgan NG, Richardson SJ, Hewison M, Hodson DJ. Vitamin-D-Binding Protein Contributes to the Maintenance of α Cell Function and Glucagon Secretion. Cell Rep 2020; 31:107761. [PMID: 32553153 PMCID: PMC7302426 DOI: 10.1016/j.celrep.2020.107761] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/22/2020] [Accepted: 05/21/2020] [Indexed: 02/06/2023] Open
Abstract
Vitamin-D-binding protein (DBP) or group-specific component of serum (GC-globulin) carries vitamin D metabolites from the circulation to target tissues. DBP is highly localized to the liver and pancreatic α cells. Although DBP serum levels, gene polymorphisms, and autoantigens have all been associated with diabetes risk, the underlying mechanisms remain unknown. Here, we show that DBP regulates α cell morphology, α cell function, and glucagon secretion. Deletion of DBP leads to smaller and hyperplastic α cells, altered Na+ channel conductance, impaired α cell activation by low glucose, and reduced rates of glucagon secretion both in vivo and in vitro. Mechanistically, this involves reversible changes in islet microfilament abundance and density, as well as changes in glucagon granule distribution. Defects are also seen in β cell and δ cell function. Immunostaining of human pancreata reveals generalized loss of DBP expression as a feature of late-onset and long-standing, but not early-onset, type 1 diabetes. Thus, DBP regulates α cell phenotype, with implications for diabetes pathogenesis.
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Affiliation(s)
- Katrina Viloria
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Linford J B Briant
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Silke Heising
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Dean P Larner
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Nicholas H F Fine
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Fiona B Ashford
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Gabriela da Silva Xavier
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Maria Jiménez Ramos
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Annie Hasib
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Federica Cuozzo
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Jocelyn E Manning Fox
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Ildem Akerman
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Christine Flaxman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Noel G Morgan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Sarah J Richardson
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Martin Hewison
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK.
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
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5
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Zhao L, Wang L, Aierken R, Wang W, Wang X, Li M. Characterization of Insulin and Glucagon Genes and Their Producing Endocrine Cells From Pygmy Sperm Whale ( Kogia breviceps). Front Endocrinol (Lausanne) 2020; 11:174. [PMID: 32296396 PMCID: PMC7137828 DOI: 10.3389/fendo.2020.00174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/11/2020] [Indexed: 02/05/2023] Open
Abstract
Insulin and glucagon are hormones secreted by pancreatic β and α cells, respectively, which together regulate glucose homeostasis. Dysregulation of insulin or glucagon can result in loss of blood glucose control, characterized by hyperglycemia or hypoglycemia. To better understand the endocrine physiology of cetaceans, we cloned and characterized the insulin and glucagon genes from pygmy sperm whale (Kogia breviceps). We obtained the complete coding sequences of the preproinsulin and preproglucagon genes, which encodes the preproinsulin protein of 110 amino acid (aa) residues and encodes the preproglucagon protein of 179 aa residues, respectively. Sequence comparison and phylogenetic analyses demonstrate that protein structures were similar to other mammalian orthologs. Immunohistochemistry and immunofluorescence staining using insulin, glucagon, and somatostatin antibodies allowed analysis of pygmy sperm whale islet distribution, architecture, and composition. Our results showed the pygmy sperm whale islet was irregularly shaped and randomly distributed throughout the pancreas. The architecture of α, β, and δ cells of the pygmy sperm whale was similar to that of artiodactyls species. This is the first report about insulin and glucagon genes in cetaceans, which provides new information about the structural conservation of the insulin and glucagon genes. Furthermore, offers novel information on the properties of endocrine cells in cetacean for further studies.
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Affiliation(s)
- Liyuan Zhao
- Laboratory of Marine Biology and Ecology, Fujian Provincial Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Likun Wang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, China
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Reyilamu Aierken
- Laboratory of Marine Biology and Ecology, Fujian Provincial Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Wei Wang
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Xianyan Wang
- Laboratory of Marine Biology and Ecology, Fujian Provincial Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
- *Correspondence: Xianyan Wang
| | - Mingyu Li
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, China
- Mingyu Li
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6
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Himuro M, Miyatsuka T, Suzuki L, Miura M, Katahira T, Goto H, Nishida Y, Sasaki S, Koike M, Shiota C, Gittes GK, Fujitani Y, Watada H. Cellular Autophagy in α Cells Plays a Role in the Maintenance of Islet Architecture. J Endocr Soc 2019; 3:1979-1992. [PMID: 31620668 PMCID: PMC6786006 DOI: 10.1210/js.2019-00075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/22/2019] [Indexed: 01/31/2023] Open
Abstract
Autophagy is known to play a pivotal role in intracellular quality control through the degradation of subcellular damaged organelles and components. Whereas autophagy is essential for maintaining β-cell function in pancreatic islets, it remains unclear as to how the cellular autophagy affects the homeostasis and function of glucagon-secreting α cells. To investigate the role of autophagy in α cells, we generated a mutant mouse model lacking Atg7, a key molecule for autophagosome formation, specifically in α cells. Histological analysis demonstrated more glucagon-positive cells, with a multilayered structure, in the islets under Atg7 deficiency, although metabolic profiles, such as body weight, blood glucose, and plasma glucagon levels were comparable between Atg7-deficient mice and control littermates. Consistent with our previous findings that Atg7 deficiency suppressed β-cell proliferation, cellular proliferation was suppressed in Atg7-deficient α cells. These findings suggest that α-cell autophagy plays a role in maintaining α-cell area and normal islet architecture but appears to be dispensable for metabolic homeostasis.
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Affiliation(s)
- Miwa Himuro
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takeshi Miyatsuka
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Luka Suzuki
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masaki Miura
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takehiro Katahira
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiromasa Goto
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuya Nishida
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shugo Sasaki
- Department of Surgery, The University of British Columbia, Vancouver BC, Canada
| | - Masato Koike
- Departments of Cell Biology and Neurosciences, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Chiyo Shiota
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - George K Gittes
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Yoshio Fujitani
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular & Cellular Regulation, Gunma University, Maebashi, Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine, Tokyo, Japan
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7
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Liu J, Banerjee A, Herring CA, Attalla J, Hu R, Xu Y, Shao Q, Simmons AJ, Dadi PK, Wang S, Jacobson DA, Liu B, Hodges E, Lau KS, Gu G. Neurog3-Independent Methylation Is the Earliest Detectable Mark Distinguishing Pancreatic Progenitor Identity. Dev Cell 2019; 48:49-63.e7. [PMID: 30620902 PMCID: PMC6327977 DOI: 10.1016/j.devcel.2018.11.048] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 08/26/2018] [Accepted: 11/29/2018] [Indexed: 12/15/2022]
Abstract
In the developing pancreas, transient Neurog3-expressing progenitors give rise to four major islet cell types: α, β, δ, and γ; when and how the Neurog3+ cells choose cell fate is unknown. Using single-cell RNA-seq, trajectory analysis, and combinatorial lineage tracing, we showed here that the Neurog3+ cells co-expressing Myt1 (i.e., Myt1+Neurog3+) were biased toward β cell fate, while those not simultaneously expressing Myt1 (Myt1-Neurog3+) favored α fate. Myt1 manipulation only marginally affected α versus β cell specification, suggesting Myt1 as a marker but not determinant for islet-cell-type specification. The Myt1+Neurog3+ cells displayed higher Dnmt1 expression and enhancer methylation at Arx, an α-fate-promoting gene. Inhibiting Dnmts in pancreatic progenitors promoted α cell specification, while Dnmt1 overexpression or Arx enhancer hypermethylation favored β cell production. Moreover, the pancreatic progenitors contained distinct Arx enhancer methylation states without transcriptionally definable sub-populations, a phenotype independent of Neurog3 activity. These data suggest that Neurog3-independent methylation on fate-determining gene enhancers specifies distinct endocrine-cell programs.
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Affiliation(s)
- Jing Liu
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Amrita Banerjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Charles A Herring
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Jonathan Attalla
- Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biochemistry and the Vanderbilt Genetic Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Ruiying Hu
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yanwen Xu
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Qiujia Shao
- Center for AIDS Health Disparities Research, Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, TN 37208, USA
| | - Alan J Simmons
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Sui Wang
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Bindong Liu
- Center for AIDS Health Disparities Research, Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, TN 37208, USA
| | - Emily Hodges
- Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biochemistry and the Vanderbilt Genetic Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Ken S Lau
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Guoqiang Gu
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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8
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Karanth S, Adams JD, Serrano MDLA, Quittner-Strom EB, Simcox J, Villanueva CJ, Ozcan L, Holland WL, Yost HJ, Vella A, Schlegel A. A Hepatocyte FOXN3- α Cell Glucagon Axis Regulates Fasting Glucose. Cell Rep 2018; 24:312-319. [PMID: 29996093 DOI: 10.1016/j.celrep.2018.06.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/07/2018] [Accepted: 06/08/2018] [Indexed: 01/26/2023] Open
Abstract
The common genetic variation at rs8004664 in the FOXN3 gene is independently and significantly associated with fasting blood glucose, but not insulin, in non-diabetic humans. Recently, we reported that primary hepatocytes from rs8004664 hyperglycemia risk allele carriers have increased FOXN3 transcript and protein levels and liver-limited overexpression of human FOXN3, a transcriptional repressor that had not been implicated in metabolic regulation previously, increases fasting blood glucose in zebrafish. Here, we find that injection of glucagon into mice and adult zebrafish decreases liver Foxn3 protein and transcript levels. Zebrafish foxn3 loss-of-function mutants have decreased fasting blood glucose, blood glucagon, liver gluconeogenic gene expression, and α cell mass. Conversely, liver-limited overexpression of foxn3 increases α cell mass. Supporting these genetic findings in model organisms, non-diabetic rs8004664 risk allele carriers have decreased suppression of glucagon during oral glucose tolerance testing. By reciprocally regulating each other, liver FOXN3 and glucagon control fasting glucose.
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Affiliation(s)
- Santhosh Karanth
- University of Utah Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - J D Adams
- Department of Internal Medicine, Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Maria de Los Angeles Serrano
- University of Utah Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Ezekiel B Quittner-Strom
- University of Utah Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah College of Health, Salt Lake City, UT, USA
| | - Judith Simcox
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Claudio J Villanueva
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Lale Ozcan
- Department of Medicine, Division of Molecular Medicine, Columbia University Medical Center, New York, NY, USA
| | - William L Holland
- University of Utah Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah College of Health, Salt Lake City, UT, USA; Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - H Joseph Yost
- University of Utah Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Adrian Vella
- Department of Internal Medicine, Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Amnon Schlegel
- University of Utah Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah College of Health, Salt Lake City, UT, USA; Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
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Katoh MC, Jung Y, Ugboma CM, Shimbo M, Kuno A, Basha WA, Kudo T, Oishi H, Takahashi S. MafB Is Critical for Glucagon Production and Secretion in Mouse Pancreatic α Cells In Vivo. Mol Cell Biol 2018; 38:e00504-17. [PMID: 29378833 DOI: 10.1128/MCB.00504-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/19/2018] [Indexed: 12/14/2022] Open
Abstract
The MafB transcription factor is expressed in pancreatic α and β cells during development but becomes exclusive to α cells in adult rodents. Mafb-null (Mafb-/- ) mice were reported to have reduced α- and β-cell numbers throughout embryonic development. To further analyze the postnatal function of MafB in the pancreas, we generated endocrine cell-specific (MafbΔEndo ) and tamoxifen-dependent (MafbΔTAM ) Mafb knockout mice. MafbΔEndo mice exhibited reduced populations of insulin-positive (insulin+) and glucagon+ cells at postnatal day 0, but the insulin+ cell population recovered by 8 weeks of age. In contrast, the Arx+ glucagon+ cell fraction and glucagon expression remained decreased even in adulthood. MafbΔTAM mice, with Mafb deleted after pancreas maturation, also demonstrated diminished glucagon+ cells and glucagon content without affecting β cells. A decreased Arx+ glucagon+ cell population in MafbΔEndo mice was compensated for by an increased Arx+ pancreatic polypeptide+ cell population. Furthermore, gene expression analyses from both MafbΔEndo and MafbΔTAM islets revealed that MafB is a key regulator of glucagon expression in α cells. Finally, both mutants failed to respond to arginine, likely due to impaired arginine transporter gene expression and glucagon production ability. Taken together, our findings reveal that MafB is critical for the functional maintenance of mouse α cells in vivo, including glucagon production and secretion, as well as in development.
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Lin HV, Wang J, Wang J, Li W, Wang X, Alston JT, Thomas MK, Briere DA, Syed SK, Efanov AM. GPR142 prompts glucagon-like Peptide-1 release from islets to improve β cell function. Mol Metab 2018; 11:205-211. [PMID: 29506910 PMCID: PMC6001353 DOI: 10.1016/j.molmet.2018.02.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/15/2018] [Accepted: 02/17/2018] [Indexed: 01/11/2023] Open
Abstract
Objective GPR142 agonists are being pursued as novel diabetes therapies by virtue of their insulin secretagogue effects. But it is undetermined whether GPR142's functions in pancreatic islets are limited to regulating insulin secretion. The current study expands research on its action. Methods and Results We demonstrated by in situ hybridization and immunostaining that GPR142 is expressed not only in β cells but also in a subset of α cells. Stimulation of GPR142 by a selective agonist increased glucagon secretion in both human and mouse islets. More importantly, the GPR142 agonist also potentiated glucagon-like peptide-1 (GLP-1) production and its release from islets through a mechanism that involves upregulation of prohormone convertase 1/3 expression. Strikingly, stimulation of insulin secretion and increase in insulin content via GPR142 engagement requires intact GLP-1 receptor signaling. Furthermore, GPR142 agonist increased β cell proliferation and protected both mouse and human islets against stress-induced apoptosis. Conclusions Collectively, we provide here evidence that local GLP-1 release from α cells defines GPR142's beneficial effects on improving β cell function and mass, and we propose that GPR142 agonism may have translatable and durable efficacy for the treatment of type 2 diabetes. GPR142 is expressed in both α cells and β cells in pancreatic islets. Stimulation of GPR142 by a selective agonist increases glucagon secretion. GPR142 agonism promotes glucagon-like peptide-1 release from islets by upregulating prohormone convertase 1/3. Increases in insulin secretion and content via GPR142 engagement require intact GLP-1 receptor signaling.
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Affiliation(s)
- Hua V Lin
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA.
| | - Jingru Wang
- Lilly China Research and Development Center, Shanghai, China
| | - Jie Wang
- Lilly China Research and Development Center, Shanghai, China
| | - Weiji Li
- Lilly China Research and Development Center, Shanghai, China
| | - Xuesong Wang
- Lilly China Research and Development Center, Shanghai, China
| | - James T Alston
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
| | - Melissa K Thomas
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
| | - Daniel A Briere
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
| | - Samreen K Syed
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
| | - Alexander M Efanov
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
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11
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Zhang H, Liu R, Deng T, Wang X, Lang H, Qu Y, Duan J, Huang D, Ying G, Ba Y. The microRNA-124-iGluR2/3 pathway regulates glucagon release from alpha cells. Oncotarget 2017; 7:24734-43. [PMID: 27013590 PMCID: PMC5029737 DOI: 10.18632/oncotarget.8270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/07/2016] [Indexed: 01/30/2023] Open
Abstract
Glucagon, secreted from islet alpha cells, plays an important role in regulating glucose homeostasis; however, the molecular mechanism underlying this process is not fully understood. Previous studies have demonstrated that miRNAs are involved in the function of alpha cells. Glutamate promotes glucagon secretion by mediating the opening of Ca2+ channels. In this present, iGluR2 and iGluR3 levels were significantly increased in fasting-treated mouse islets. Additional studies showed that miR-124-3p simultaneously regulates the expression of iGluR2 and iGluR3 through the direct targeting of mRNA 3’UTR of these two genes. The miR-124-iGluRs pathway also contributed to the high level of glucagon secretion through long-term high glucose levels. Thus, a novel pathway comprising miRNA, glutamate and iGluRs has been demonstrated to regulate the biological process of glucagon release.
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Affiliation(s)
- Haiyang Zhang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Rui Liu
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Ting Deng
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Xia Wang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Hongmei Lang
- Department of Endocrinology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, China
| | - Yanjun Qu
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Jingjing Duan
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Dingzhi Huang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Guoguang Ying
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Yi Ba
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
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12
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Traub S, Meier DT, Schulze F, Dror E, Nordmann TM, Goetz N, Koch N, Dalmas E, Stawiski M, Makshana V, Thorel F, Herrera PL, Böni-Schnetzler M, Donath MY. Pancreatic α Cell-Derived Glucagon-Related Peptides Are Required for β Cell Adaptation and Glucose Homeostasis. Cell Rep 2017; 18:3192-3203. [PMID: 28355570 DOI: 10.1016/j.celrep.2017.03.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/22/2017] [Accepted: 03/01/2017] [Indexed: 02/04/2023] Open
Abstract
Pancreatic α cells may process proglucagon not only to glucagon but also to glucagon-like peptide-1 (GLP-1). However, the biological relevance of paracrine GLP-1 for β cell function remains unclear. We studied effects of locally derived insulin secretagogues on β cell function and glucose homeostasis using mice with α cell ablation and with α cell-specific GLP-1 deficiency. Normally, intestinal GLP-1 compensates for the lack of α cell-derived GLP-1. However, upon aging and metabolic stress, glucose tolerance is impaired. This was partly rescued with the DPP-4 inhibitor sitagliptin, but not with glucagon administration. In isolated islets from these mice, glucose-stimulated insulin secretion was heavily impaired and exogenous GLP-1 or glucagon rescued insulin secretion. These data highlight the importance of α cell-derived GLP-1 for glucose homeostasis during metabolic stress and may impact on the clinical use of systemic GLP-1 agonists versus stabilizing local α cell-derived GLP-1 by DPP-4 inhibitors in type 2 diabetes.
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Affiliation(s)
- Shuyang Traub
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Daniel T Meier
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Friederike Schulze
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Erez Dror
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Thierry M Nordmann
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Nicole Goetz
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Norina Koch
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Elise Dalmas
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Marc Stawiski
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Valmir Makshana
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland; Centre facultaire du diabète, University of Geneva, 1211 Geneva, Switzerland
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland; Centre facultaire du diabète, University of Geneva, 1211 Geneva, Switzerland
| | - Marianne Böni-Schnetzler
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Marc Y Donath
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland.
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13
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Qiu WL, Zhang YW, Feng Y, Li LC, Yang L, Xu CR. Deciphering Pancreatic Islet β Cell and α Cell Maturation Pathways and Characteristic Features at the Single-Cell Level. Cell Metab 2017; 25:1194-1205.e4. [PMID: 28467935 DOI: 10.1016/j.cmet.2017.04.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/03/2017] [Accepted: 04/05/2017] [Indexed: 02/02/2023]
Abstract
Pancreatic β and α cells play essential roles in maintaining glucose homeostasis. However, the mechanisms by which these distinct cell populations are generated, expand, and mature during pancreas development remain unclear. In this study, we addressed this critical question by performing a single-cell transcriptomic analysis of mouse β and α cells sorted from fetal to adult stages. We discovered that β and α cells use different regulatory strategies for their maturation and that cell proliferation peaks at different developmental times. However, the quiescent and proliferative cells in both the β lineage and α lineage are synchronous in their maturation states. The heterogeneity of juvenile β cells reflects distinct cell-cycling phases, origins, and maturation states, whereas adult β cells are relatively homogeneous at the transcriptomic level. These analyses provide not only a high-resolution roadmap for islet lineage development but also insights into the mechanisms of cellular heterogeneity, cell number expansion, and maturation of both β and α cells.
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Affiliation(s)
- Wei-Lin Qiu
- Ministry of Education Key Laboratory of Cell Proliferation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; PKU-Tsinghua-NIBS Graduate Program, Peking University, Beijing 100871, China
| | - Yu-Wei Zhang
- Ministry of Education Key Laboratory of Cell Proliferation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Ye Feng
- Ministry of Education Key Laboratory of Cell Proliferation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; PKU-Tsinghua-NIBS Graduate Program, Peking University, Beijing 100871, China
| | - Lin-Chen Li
- Ministry of Education Key Laboratory of Cell Proliferation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Liu Yang
- Ministry of Education Key Laboratory of Cell Proliferation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Cheng-Ran Xu
- Ministry of Education Key Laboratory of Cell Proliferation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
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14
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Soedling H, Hodson DJ, Adrianssens AE, Gribble FM, Reimann F, Trapp S, Rutter GA. Limited impact on glucose homeostasis of leptin receptor deletion from insulin- or proglucagon-expressing cells. Mol Metab 2015; 4:619-30. [PMID: 26413468 PMCID: PMC4563029 DOI: 10.1016/j.molmet.2015.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/12/2015] [Indexed: 01/07/2023] Open
Abstract
AIMS/HYPOTHESIS The adipose tissue-derived hormone leptin plays an important role in the maintenance of body weight and glucose homeostasis. Leptin mediates its effects by interaction with leptin receptors (LepRb), which are highly expressed in the hypothalamus and other brain centres, and at lower levels in the periphery. Previous studies have used relatively promiscuous or inefficient Cre deleter strains, respectively, to explore the roles of LepR in pancreatic β and α cells. Here, we use two newly-developed Cre lines to explore the role of leptin signalling in insulin and proglucagon-expressing cells. METHODS Leptin receptor expression was measured in isolated mouse islets and highly-purified islet cells by RNASeq and quantitative RT-PCR. Mice lacking leptin signalling in pancreatic β, or in α and other proglucagon-expressing cells, were generated using Ins1Cre- or iGluCre-mediated recombination respectively of flox'd leptin receptor alleles. In vivo glucose homeostasis, changes in body weight, pancreatic histology and hormone secretion from isolated islets were assessed using standard techniques. RESULTS Leptin receptor mRNA levels were at or below the level of detection in wild-type adult mouse isolated islets and purified cells, and leptin signalling to Stat3 phosphorylation was undetectable. Whereas male mice further deleted for leptin receptors in β cells exhibited no abnormalities in glucose tolerance up to 16 weeks of age, females transiently displayed improved glucose tolerance at 8 weeks (11.2 ± 3.2% decrease in area under curve; p < 0.05), and improved (39.0 ± 13.0%, P < 0.05) glucose-stimulated insulin secretion in vitro. No differences were seen between genotypes in body weight, fasting glucose or β/α cell ratio. Deletion of LepR from α-cells, a minority of β cells, and a subset of proglucagon-expressing cells in the brain, exerted no effects on body weight, glucose or insulin tolerance, nor on pancreatic hormone secretion assessed in vivo and in vitro. CONCLUSIONS/INTERPRETATION The use here of a highly selective Cre recombinase indicates that leptin signalling plays a relatively minor, age- and sex-dependent role in the control of β cell function in the mouse. No in vivo role for leptin receptors on α cells, nor in other proglucagon-expressing cells, was detected in this study.
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Affiliation(s)
- Helen Soedling
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, du Cane Road, London W12 0NN, UK
| | - David J Hodson
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, du Cane Road, London W12 0NN, UK
| | | | - Fiona M Gribble
- University of Cambridge Metabolic Research Laboratories, Cambridge, UK
| | - Frank Reimann
- University of Cambridge Metabolic Research Laboratories, Cambridge, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, du Cane Road, London W12 0NN, UK
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15
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Abstract
The α and β cells act in concert to maintain blood glucose. The α cells release glucagon in response to low levels of glucose to stimulate glycogenolysis in the liver. In contrast, β cells release insulin in response to elevated levels of glucose to stimulate peripheral glucose disposal. Despite these opposing roles in glucose homeostasis, α and β cells are derived from a common progenitor and share many proteins important for glucose sensing and hormone secretion. Results from recent work have underlined these similarities between the two cell types by revealing that β-to-α as well as α-to-β transdifferentiation can take place under certain experimental circumstances. These exciting findings highlight unexpected plasticity of adult islets and offer hope of novel therapeutic paths to replenish β cells in diabetes. In this review, we focus on the transcription factor networks that establish and maintain pancreatic endocrine cell identity and how they may be perturbed to facilitate transdifferentiation.
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Affiliation(s)
- Talitha van der Meulen
- Department of NeurobiologyPhysiology and Behavior, College of Biological SciencesDepartment of Physiology and Membrane BiologySchool of Medicine, University of California, 193 Briggs Hall, One Shields Avenue, Davis, California 95616, USA
| | - Mark O Huising
- Department of NeurobiologyPhysiology and Behavior, College of Biological SciencesDepartment of Physiology and Membrane BiologySchool of Medicine, University of California, 193 Briggs Hall, One Shields Avenue, Davis, California 95616, USA Department of NeurobiologyPhysiology and Behavior, College of Biological SciencesDepartment of Physiology and Membrane BiologySchool of Medicine, University of California, 193 Briggs Hall, One Shields Avenue, Davis, California 95616, USA
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16
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Abstract
Incretin-based therapy such as GLP-1 receptor agonists and DPP-4 inhibitors for type 2 diabetes mellitus is characterized by glucose-dependent insulin secretion and glucose-inhibited glucagon secretion. Recently, autophagy deficiency in islet β cells has been shown to contribute to the pathogenesis of type 2 diabetes mellitus however, with the role of incretin has not been established. To evaluate the role of autophagy in incretin effects, 8-week-old male β cell-specific Atg7 knockout (Atg7(Δβ cell)) mice and wild-type mice were administered vildagliptin for 12 weeks. Vildagliptin treatment improved glucose intolerance and hypoinsulinemia; however, it failed to suppress serum glucagon levels after glucose loading in the Atg7(Δβ cell) mice. Ex vivo glucose-induced glucagon suppression was also blunted in the islets from vildagliptin-treated Atg7(Δβ cell) mice. The α cell mass was not affected by β cell autophagy deficiency or vildagliptin. However, glucagon mRNA expression was significantly increased by vildagliptin in the autophagy-deficient islets, and was significantly reduced by vildagliptin in wild-type islets. Pancreatic glucagon contents were not in agreement with the changes in mRNA expression, suggesting a dysregulation in glucagon translation and secretion. In vitro studies revealed that glucose-stimulated cAMP production was impaired in the autophagy-deficient islets exposed to exendin-4. Taken together, the results suggest that the constitutive autophagy in β cells could regulate incretin-induced glucagon expression and release in α cells, and that cAMP may play a role in this process.
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Affiliation(s)
- Min Joo Kim
- Department of Internal Medicine; Seoul National University College of Medicine; Seoul, Republic of Korea
- Department of Internal Medicine; Korea Cancer Center Hospital; Seoul, Republic of Korea
| | - Ok Kyong Choi
- Innovative Research Institute for Cell Therapy; Seoul, Republic of Korea
| | - Kyung Sil Chae
- Innovative Research Institute for Cell Therapy; Seoul, Republic of Korea
| | - Hakmo Lee
- Innovative Research Institute for Cell Therapy; Seoul, Republic of Korea
| | - Sung Soo Chung
- Innovative Research Institute for Cell Therapy; Seoul, Republic of Korea
| | - Dong-Sik Ham
- Department of Endocrinology and Metabolism; The Catholic University of Korea; Seoul, Republic of Korea
| | - Ji-Won Kim
- Department of Endocrinology and Metabolism; The Catholic University of Korea; Seoul, Republic of Korea
| | - Kun-Ho Yoon
- Department of Endocrinology and Metabolism; The Catholic University of Korea; Seoul, Republic of Korea
| | - Kyong Soo Park
- Department of Internal Medicine; Seoul National University College of Medicine; Seoul, Republic of Korea
- Innovative Research Institute for Cell Therapy; Seoul, Republic of Korea
| | - Hye Seung Jung
- Department of Internal Medicine; Seoul National University College of Medicine; Seoul, Republic of Korea
- Innovative Research Institute for Cell Therapy; Seoul, Republic of Korea
- Correspondence to: Hye Seung Jung;
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Zaghloul KA, Boahen K, Demb JB. Different circuits for ON and OFF retinal ganglion cells cause different contrast sensitivities. J Neurosci 2003; 23:2645-54. [PMID: 12684450 PMCID: PMC6742092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
The theory of "parallel pathways" predicts that, except for a sign reversal, ON and OFF ganglion cells are driven by a similar presynaptic circuit. To test this hypothesis, we measured synaptic inputs to ON and OFF cells as reflected in the subthreshold membrane potential. We made intracellular recordings from brisk-transient (Y) cells in the in vitro guinea pig retina and show that ON and OFF cells in fact express significant asymmetries in their synaptic inputs. An ON cell receives relatively linear input that modulates a single excitatory conductance; whereas an OFF cell receives rectified input that modulates both inhibitory and excitatory conductances. The ON pathway, blocked by L-AP-4, tonically inhibits an OFF cell at mean luminance and phasically inhibits an OFF cell during a light increment. Our results suggest that basal glutamate release is high at ON but not OFF bipolar terminals, and inhibition between pathways is unidirectional: ON --> OFF. These circuit asymmetries explain asymmetric contrast sensitivity observed in spiking behavior.
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Affiliation(s)
- Kareem A Zaghloul
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6058, USA
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