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Zhang S, Zhang Y, Wen Z, Chen Y, Bu T, Yang Y, Ni Q. Enhancing β-cell function and identity in type 2 diabetes: The protective role of Coptis deltoidea C. Y. Cheng et Hsiao via glucose metabolism modulation and AMPK signaling activation. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 128:155396. [PMID: 38547617 DOI: 10.1016/j.phymed.2024.155396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 01/10/2024] [Accepted: 01/24/2024] [Indexed: 05/01/2024]
Abstract
BACKGROUND Abnormalities in glucose metabolism may be the underlying cause of β-cell dysfunction and identity impairment resulting from high glucose exposure. In China, Coptis deltoidea C. Y. Cheng et Hsiao (YL) has demonstrated remarkable hypoglycemic effects. HYPOTHESIS/PURPOSE To investigate the hypoglycemic effect of YL and determine the mechanism of YL in treating diabetes. METHODS A type 2 diabetes mouse model was used to investigate the pharmacodynamics of YL. YL was administrated once daily for 8 weeks. The hypoglycemic effect of YL was assessed by fasting blood glucose, an oral glucose tolerance test, insulin levels, and other indexes. The underlying mechanism of YL was examined by targeting glucose metabolomics, western blotting, and qRT-PCR. Subsequently, the binding capacity between predicted AMP-activated protein kinase (AMPK) and important components of YL (Cop, Ber, and Epi) were validated by molecular docking and surface plasmon resonance. Then, in AMPK knockdown MIN6 cells, the mechanisms of Cop, Ber, and Epi were inversely confirmed through evaluations encompassing glucose-stimulated insulin secretion, markers indicative of β-cell identity, and the examination of glycolytic genes and products. RESULTS YL (0.9 g/kg) treatment exerted notable hypoglycemic effects and protected the structural integrity and identity of pancreatic β-cells. Metabolomic analysis revealed that YL inhibited the hyperactivated glycolysis pathway in diabetic mice, thereby regulating the products of the tricarboxylic acid cycle. KEGG enrichment revealed the intimate relationship of this process with the AMPK signaling pathway. Cop, Ber, and Epi in YL displayed high binding affinities for AMPK protein. These compounds played a pivotal role in preserving the identity of pancreatic β-cells and amplifying insulin secretion. The mechanism underlying this process involved inhibition of glucose uptake, lowering intracellular lactate levels, and elevating acetyl coenzyme A and ATP levels through AMPK signaling. The use of a glycolytic inhibitor corroborated that attenuation of glycolysis restored β-cell identity and function. CONCLUSION YL demonstrates significant hypoglycemic efficacy. We elucidated the potential mechanisms underlying the protective effects of YL and its active constituents on β-cell function and identity by observing glucose metabolism processes in pancreatic tissue and cells. In this intricate process, AMPK plays a pivotal regulatory role.
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Affiliation(s)
- Shan Zhang
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Yueying Zhang
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Zhige Wen
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Yupeng Chen
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Tianjie Bu
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Yanan Yang
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Qing Ni
- Department of Endocrinology, Guang' anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
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Jacovetti C, Donnelly C, Menoud V, Suleiman M, Cosentino C, Sobel J, Wu K, Bouzakri K, Marchetti P, Guay C, Kayser B, Regazzi R. The mitochondrial tRNA-derived fragment, mt-tRF-Leu TAA, couples mitochondrial metabolism to insulin secretion. Mol Metab 2024; 84:101955. [PMID: 38704026 PMCID: PMC11112368 DOI: 10.1016/j.molmet.2024.101955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024] Open
Abstract
OBJECTIVE The contribution of the mitochondrial electron transfer system to insulin secretion involves more than just energy provision. We identified a small RNA fragment (mt-tRF-LeuTAA) derived from the cleavage of a mitochondrially-encoded tRNA that is conserved between mice and humans. The role of mitochondrially-encoded tRNA-derived fragments remains unknown. This study aimed to characterize the impact of mt-tRF-LeuTAA, on mitochondrial metabolism and pancreatic islet functions. METHODS We used antisense oligonucleotides to reduce mt-tRF-LeuTAA levels in primary rat and human islet cells, as well as in insulin-secreting cell lines. We performed a joint transcriptome and proteome analysis upon mt-tRF-LeuTAA inhibition. Additionally, we employed pull-down assays followed by mass spectrometry to identify direct interactors of the fragment. Finally, we characterized the impact of mt-tRF-LeuTAA silencing on the coupling between mitochondrial metabolism and insulin secretion using high-resolution respirometry and insulin secretion assays. RESULTS Our study unveils a modulation of mt-tRF-LeuTAA levels in pancreatic islets in different Type 2 diabetes models and in response to changes in nutritional status. The level of the fragment is finely tuned by the mechanistic target of rapamycin complex 1. Located within mitochondria, mt-tRF-LeuTAA interacts with core subunits and assembly factors of respiratory complexes of the electron transfer system. Silencing of mt-tRF-LeuTAA in islet cells limits the inner mitochondrial membrane potential and impairs mitochondrial oxidative phosphorylation, predominantly by affecting the Succinate (via Complex II)-linked electron transfer pathway. Lowering mt-tRF-LeuTAA impairs insulin secretion of rat and human pancreatic β-cells. CONCLUSIONS Our findings indicate that mt-tRF-LeuTAA interacts with electron transfer system complexes and is a pivotal regulator of mitochondrial oxidative phosphorylation and its coupling to insulin secretion.
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Affiliation(s)
- Cecile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
| | - Chris Donnelly
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Véronique Menoud
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Mara Suleiman
- Department of Clinical and Experimental Medicine, Diabetes Unit, University of Pisa, Pisa, Italy
| | - Cristina Cosentino
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jonathan Sobel
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Kejing Wu
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Karim Bouzakri
- UMR DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, Diabetes Unit, University of Pisa, Pisa, Italy
| | - Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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3
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Patel S, Yan Z, Remedi MS. Intermittent fasting protects β-cell identity and function in a type-2 diabetes model. Metabolism 2024; 153:155813. [PMID: 38307325 PMCID: PMC10985623 DOI: 10.1016/j.metabol.2024.155813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/28/2024] [Accepted: 01/29/2024] [Indexed: 02/04/2024]
Abstract
Type 2 diabetes (T2DM) is caused by the interaction of multiple genes and environmental factors. T2DM is characterized by hyperglycemia, insulin secretion deficiency and insulin resistance. Chronic hyperglycemia induces β-cell dysfunction, loss of β-cell mass/identity and β-cell dedifferentiation. Intermittent fasting (IF) a commonly used dietary regimen for weight-loss, also induces metabolic benefits including reduced blood glucose, improved insulin sensitivity, reduced adiposity, inflammation, oxidative-stress and increased fatty-acid oxidation; however, the mechanisms underlying these effects in pancreatic β-cells remain elusive. KK and KKAy, mouse models of polygenic T2DM spontaneously develop hyperglycemia, glucose intolerance, glucosuria, impaired insulin secretion and insulin resistance. To determine the long-term effects of IF on T2DM, 6-weeks old KK and KKAy mice were subjected to IF for 16 weeks. While KKAy mice fed ad-libitum demonstrated severe hyperglycemia (460 mg/dL) at 6 weeks of age, KK mice showed blood glucose levels of 230 mg/dL, but progressively became severely diabetic by 22-weeks. Strikingly, both KK and KKAy mice subjected to IF showed reduced blood glucose and plasma insulin levels, decreased body weight gain, reduced plasma triglycerides and cholesterol, and improved insulin sensitivity. They also demonstrated enhanced expression of the β-cell transcription factors NKX6.1, MAFA and PDX1, and decreased expression of ALDH1a3 suggesting protection from loss of β-cell identity by IF. IF normalized glucose stimulated insulin secretion in islets from KK and KKAy mice, demonstrating improved β-cell function. In addition, hepatic steatosis, gluconeogenesis and inflammation was decreased particularly in KKAy-IF mice, indicating peripheral benefits of IF. These results have important implications as an optional intervention for preservation of β-cell identity and function in T2DM.
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Affiliation(s)
- Sumit Patel
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, United States of America
| | - Zihan Yan
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, United States of America
| | - Maria S Remedi
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, United States of America; Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, United States of America; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, United States of America.
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4
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Pfaller AM, Kaplan L, Carido M, Grassmann F, Díaz-Lezama N, Ghaseminejad F, Wunderlich KA, Glänzer S, Bludau O, Pannicke T, Weber BHF, Koch SF, Bonev B, Hauck SM, Grosche A. The glucocorticoid receptor as a master regulator of the Müller cell response to diabetic conditions in mice. J Neuroinflammation 2024; 21:33. [PMID: 38273366 PMCID: PMC10809506 DOI: 10.1186/s12974-024-03021-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 01/11/2024] [Indexed: 01/27/2024] Open
Abstract
Diabetic retinopathy (DR) is considered a primarily microvascular complication of diabetes. Müller glia cells are at the centre of the retinal neurovascular unit and play a critical role in DR. We therefore investigated Müller cell-specific signalling pathways that are altered in DR to identify novel targets for gene therapy. Using a multi-omics approach on purified Müller cells from diabetic db/db mice, we found the mRNA and protein expression of the glucocorticoid receptor (GR) to be significantly decreased, while its target gene cluster was down-regulated. Further, oPOSSUM TF analysis and ATAC- sequencing identified the GR as a master regulator of Müller cell response to diabetic conditions. Cortisol not only increased GR phosphorylation. It also induced changes in the expression of known GR target genes in retinal explants. Finally, retinal functionality was improved by AAV-mediated overexpression of GR in Müller cells. Our study demonstrates an important role of the glial GR in DR and implies that therapeutic approaches targeting this signalling pathway should be aimed at increasing GR expression rather than the addition of more ligand.
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Affiliation(s)
- Anna M Pfaller
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Lew Kaplan
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Madalena Carido
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Felix Grassmann
- Institute of Clinical Human Genetics, University Hospital Regensburg, Regensburg, Germany
- Institute for Clinical Research and Systems Medicine, Health and Medical University, Potsdam, Germany
| | - Nundehui Díaz-Lezama
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Farhad Ghaseminejad
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Kirsten A Wunderlich
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Institute for Molecular Medicine, Health and Medical University, Potsdam, Germany
| | - Sarah Glänzer
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Oliver Bludau
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Thomas Pannicke
- Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
| | - Bernhard H F Weber
- Institute of Clinical Human Genetics, University Hospital Regensburg, Regensburg, Germany
- Institute of Human Genetics, University Regensburg, Regensburg, Germany
| | - Susanne F Koch
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Boyan Bonev
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Antje Grosche
- Department of Physiological Genomics, Biomedical Center-BMC, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
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Urizar AI, Prause M, Ingerslev LR, Wortham M, Sui Y, Sander M, Williams K, Barrès R, Larsen MR, Christensen GL, Billestrup N. Beta cell dysfunction induced by bone morphogenetic protein (BMP)-2 is associated with histone modifications and decreased NeuroD1 chromatin binding. Cell Death Dis 2023; 14:399. [PMID: 37407581 DOI: 10.1038/s41419-023-05906-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 05/09/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023]
Abstract
Insufficient insulin secretion is a hallmark of type 2 diabetes and has been attributed to beta cell identity loss characterized by decreased expression of several key beta cell genes. The pro-inflammatory factor BMP-2 is upregulated in islets of Langerhans from individuals with diabetes and acts as an inhibitor of beta cell function and proliferation. Exposure to BMP-2 induces expression of Id1-4, Hes-1, and Hey-1 which are transcriptional regulators associated with loss of differentiation. The aim of this study was to investigate the mechanism by which BMP-2 induces beta cell dysfunction and loss of cell maturity. Mouse islets exposed to BMP-2 for 10 days showed impaired glucose-stimulated insulin secretion and beta cell proliferation. BMP-2-induced beta cell dysfunction was associated with decreased expression of cell maturity and proliferation markers specific to the beta cell such as Ins1, Ucn3, and Ki67 and increased expression of Id1-4, Hes-1, and Hey-1. The top 30 most regulated proteins significantly correlated with corresponding mRNA expression. BMP-2-induced gene expression changes were associated with a predominant reduction in acetylation of H3K27 and a decrease in NeuroD1 chromatin binding activity. These results show that BMP-2 induces loss of beta cell maturity and suggest that remodeling of H3K27ac and decreased NeuroD1 DNA binding activity participate in the effect of BMP-2 on beta cell dysfunction.
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Affiliation(s)
| | - Michala Prause
- Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Lars Roed Ingerslev
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Matthew Wortham
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yinghui Sui
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Maike Sander
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Kristine Williams
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Romain Barrès
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université de Nice Côte d'Azur, Valbonne, France
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | | | - Nils Billestrup
- Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark.
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6
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Emri E, Cappa O, Kelly C, Kortvely E, SanGiovanni JP, McKay BS, Bergen AA, Simpson DA, Lengyel I. Zinc Supplementation Induced Transcriptional Changes in Primary Human Retinal Pigment Epithelium: A Single-Cell RNA Sequencing Study to Understand Age-Related Macular Degeneration. Cells 2023; 12:773. [PMID: 36899910 PMCID: PMC10000409 DOI: 10.3390/cells12050773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
Zinc supplementation has been shown to be beneficial to slow the progression of age-related macular degeneration (AMD). However, the molecular mechanism underpinning this benefit is not well understood. This study used single-cell RNA sequencing to identify transcriptomic changes induced by zinc supplementation. Human primary retinal pigment epithelial (RPE) cells could mature for up to 19 weeks. After 1 or 18 weeks in culture, we supplemented the culture medium with 125 µM added zinc for one week. RPE cells developed high transepithelial electrical resistance, extensive, but variable pigmentation, and deposited sub-RPE material similar to the hallmark lesions of AMD. Unsupervised cluster analysis of the combined transcriptome of the cells isolated after 2, 9, and 19 weeks in culture showed considerable heterogeneity. Clustering based on 234 pre-selected RPE-specific genes divided the cells into two distinct clusters, we defined as more and less differentiated cells. The proportion of more differentiated cells increased with time in culture, but appreciable numbers of cells remained less differentiated even at 19 weeks. Pseudotemporal ordering identified 537 genes that could be implicated in the dynamics of RPE cell differentiation (FDR < 0.05). Zinc treatment resulted in the differential expression of 281 of these genes (FDR < 0.05). These genes were associated with several biological pathways with modulation of ID1/ID3 transcriptional regulation. Overall, zinc had a multitude of effects on the RPE transcriptome, including several genes involved in pigmentation, complement regulation, mineralization, and cholesterol metabolism processes associated with AMD.
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Affiliation(s)
- Eszter Emri
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University of Belfast, Belfast BT97BL, UK
- Section Ophthalmogenetics, Department of Human Genetics, Queen Emma Centre for Precision Medicine, Amsterdam UMC, Location AMC, 1105AZ Amsterdam, The Netherlands
| | - Oisin Cappa
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University of Belfast, Belfast BT97BL, UK
| | - Caoimhe Kelly
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University of Belfast, Belfast BT97BL, UK
| | - Elod Kortvely
- Immunology, Infectious Diseases and Ophthalmology (I2O) Discovery and Translational Area, Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
| | - John Paul SanGiovanni
- Biosciences Research Laboratories, BIO5 Institute, University of Arizona, 1230 North Cherry Avenue, Tucson, AZ 85724, USA
| | - Brian S. McKay
- Department of Ophthalmology and Vision Science, University of Arizona, 1656 E. Mabel Street, Tucson, AZ 85724, USA
| | - Arthur A. Bergen
- Section Ophthalmogenetics, Department of Human Genetics, Queen Emma Centre for Precision Medicine, Amsterdam UMC, Location AMC, 1105AZ Amsterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN-KNAW), 1105AZ Amsterdam, The Netherlands
| | - David A. Simpson
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University of Belfast, Belfast BT97BL, UK
| | - Imre Lengyel
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University of Belfast, Belfast BT97BL, UK
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7
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Mukai E, Fujimoto S, Inagaki N. Role of Reactive Oxygen Species in Glucose Metabolism Disorder in Diabetic Pancreatic β-Cells. Biomolecules 2022; 12:biom12091228. [PMID: 36139067 PMCID: PMC9496160 DOI: 10.3390/biom12091228] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/28/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
The dysfunction of pancreatic β-cells plays a central role in the onset and progression of type 2 diabetes mellitus (T2DM). Insulin secretory defects in β-cells are characterized by a selective impairment of glucose stimulation, and a reduction in glucose-induced ATP production, which is essential for insulin secretion. High glucose metabolism for insulin secretion generates reactive oxygen species (ROS) in mitochondria. In addition, the expression of antioxidant enzymes is very low in β-cells. Therefore, β-cells are easily exposed to oxidative stress. In islet studies using a nonobese T2DM animal model that exhibits selective impairment of glucose-induced insulin secretion (GSIS), quenching ROS generated by glucose stimulation and accumulated under glucose toxicity can improve impaired GSIS. Acute ROS generation and toxicity cause glucose metabolism disorders through different molecular mechanisms. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, is a master regulator of antioxidant defense and a potential therapeutic target in oxidative stress-related diseases, suggesting the possible involvement of Nrf2 in β-cell dysfunction caused by ROS. In this review, we describe the mechanisms of insulin secretory defects induced by oxidative stress in diabetic β-cells.
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Affiliation(s)
- Eri Mukai
- Medical Physiology and Metabolism Laboratory, Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kusatsu 5258577, Japan
- Correspondence:
| | - Shimpei Fujimoto
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi 7838505, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto 6068507, Japan
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8
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Katz LS, Brill G, Zhang P, Kumar A, Baumel-Alterzon S, Honig LB, Gómez-Banoy N, Karakose E, Tanase M, Doridot L, Alvarsson A, Davenport B, Wang P, Lambertini L, Stanley SA, Homann D, Stewart AF, Lo JC, Herman MA, Garcia-Ocaña A, Scott DK. Maladaptive positive feedback production of ChREBPβ underlies glucotoxic β-cell failure. Nat Commun 2022; 13:4423. [PMID: 35908073 PMCID: PMC9339008 DOI: 10.1038/s41467-022-32162-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/18/2022] [Indexed: 01/05/2023] Open
Abstract
Preservation and expansion of β-cell mass is a therapeutic goal for diabetes. Here we show that the hyperactive isoform of carbohydrate response-element binding protein (ChREBPβ) is a nuclear effector of hyperglycemic stress occurring in β-cells in response to prolonged glucose exposure, high-fat diet, and diabetes. We show that transient positive feedback induction of ChREBPβ is necessary for adaptive β-cell expansion in response to metabolic challenges. Conversely, chronic excessive β-cell-specific overexpression of ChREBPβ results in loss of β-cell identity, apoptosis, loss of β-cell mass, and diabetes. Furthermore, β-cell "glucolipotoxicity" can be prevented by deletion of ChREBPβ. Moreover, ChREBPβ-mediated cell death is mitigated by overexpression of the alternate CHREBP gene product, ChREBPα, or by activation of the antioxidant Nrf2 pathway in rodent and human β-cells. We conclude that ChREBPβ, whether adaptive or maladaptive, is an important determinant of β-cell fate and a potential target for the preservation of β-cell mass in diabetes.
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Affiliation(s)
- Liora S Katz
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Gabriel Brill
- Pharmacologic Sciences Department, Stony Brook University, Stony Brook, NY, USA
| | - Pili Zhang
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Anil Kumar
- Metabolic Phenotyping Core, University of Utah, 15N 2030 E, 585, Radiobiology building, Room 151, Salt Lake City, UT, 84112, USA
| | - Sharon Baumel-Alterzon
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Lee B Honig
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Nicolás Gómez-Banoy
- Weill Center for Metabolic Health and Division of Cardiology, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Esra Karakose
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Marius Tanase
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Ludivine Doridot
- Institut Cochin, Université de Paris, INSERM, CNRS, F-75014, Paris, France
| | - Alexandra Alvarsson
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
- Alpenglow Biosciences, Inc., 98103, Seattle, WA, USA
| | - Bennett Davenport
- 12800 East 19th Ave, Anschutz Medical Campus, Room P18-9403, University of Colorado, Aurora, CO, 80045, USA
| | - Peng Wang
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Luca Lambertini
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Sarah A Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Dirk Homann
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Andrew F Stewart
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - James C Lo
- Weill Center for Metabolic Health and Division of Cardiology, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Mark A Herman
- Division of Endocrinology and Metabolism and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA
- Section of Diabetes, Endocrinology, and Metabolism, Baylor College of Medicine, One Baylor Plaza, MS: 185, R614, 77030, Houston, TX, USA
| | - Adolfo Garcia-Ocaña
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA
| | - Donald K Scott
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1152, New York, 10029, USA.
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9
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Lee K, Chan JY, Liang C, Ip CK, Shi YC, Herzog H, Hughes WE, Bensellam M, Delghingaro-Augusto V, Koina ME, Nolan CJ, Laybutt DR. XBP1 maintains beta cell identity, represses beta-to-alpha cell transdifferentiation and protects against diabetic beta cell failure during metabolic stress in mice. Diabetologia 2022; 65:984-996. [PMID: 35316840 PMCID: PMC9076738 DOI: 10.1007/s00125-022-05669-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/13/2021] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS Pancreatic beta cell dedifferentiation, transdifferentiation into other islet cells and apoptosis have been implicated in beta cell failure in type 2 diabetes, although the mechanisms are poorly defined. The endoplasmic reticulum stress response factor X-box binding protein 1 (XBP1) is a major regulator of the unfolded protein response. XBP1 expression is reduced in islets of people with type 2 diabetes, but its role in adult differentiated beta cells is unclear. Here, we assessed the effects of Xbp1 deletion in adult beta cells and tested whether XBP1-mediated unfolded protein response makes a necessary contribution to beta cell compensation in insulin resistance states. METHODS Mice with inducible beta cell-specific Xbp1 deletion were studied under normal (chow diet) or metabolic stress (high-fat diet or obesity) conditions. Glucose tolerance, insulin secretion, islet gene expression, alpha cell mass, beta cell mass and apoptosis were assessed. Lineage tracing was used to determine beta cell fate. RESULTS Deletion of Xbp1 in adult mouse beta cells led to beta cell dedifferentiation, beta-to-alpha cell transdifferentiation and increased alpha cell mass. Cell lineage-specific analyses revealed that Xbp1 deletion deactivated beta cell identity genes (insulin, Pdx1, Nkx6.1, Beta2, Foxo1) and derepressed beta cell dedifferentiation (Aldh1a3) and alpha cell (glucagon, Arx, Irx2) genes. Xbp1 deletion in beta cells of obese ob/ob or high-fat diet-fed mice triggered diabetes and worsened glucose intolerance by disrupting insulin secretory capacity. Furthermore, Xbp1 deletion increased beta cell apoptosis under metabolic stress conditions by attenuating the antioxidant response. CONCLUSIONS/INTERPRETATION These findings indicate that XBP1 maintains beta cell identity, represses beta-to-alpha cell transdifferentiation and is required for beta cell compensation and prevention of diabetes in insulin resistance states.
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Affiliation(s)
- Kailun Lee
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Jeng Yie Chan
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Cassandra Liang
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Chi Kin Ip
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Yan-Chuan Shi
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Herbert Herzog
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - William E Hughes
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Mohammed Bensellam
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Viviane Delghingaro-Augusto
- Medical School and John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Mark E Koina
- ACT Pathology, Canberra Health Services, Garran, ACT, Australia
| | - Christopher J Nolan
- Medical School and John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
- Department of Endocrinology, The Canberra Hospital, Garran, ACT, Australia
| | - D Ross Laybutt
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia.
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10
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Glucagon-receptor-antagonism-mediated β-cell regeneration as an effective anti-diabetic therapy. Cell Rep 2022; 39:110872. [PMID: 35649369 DOI: 10.1016/j.celrep.2022.110872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 02/12/2022] [Accepted: 05/04/2022] [Indexed: 01/10/2023] Open
Abstract
Type 1 diabetes mellitus (T1D) is a chronic disease with potentially severe complications, and β-cell deficiency underlies this disease. Despite active research, no therapy to date has been able to induce β-cell regeneration in humans. Here, we discover the β-cell regenerative effects of glucagon receptor antibody (anti-GcgR). Treatment with anti-GcgR in mouse models of β-cell deficiency leads to reversal of hyperglycemia, increase in plasma insulin levels, and restoration of β-cell mass. We demonstrate that both β-cell proliferation and α- to β-cell transdifferentiation contribute to anti-GcgR-induced β-cell regeneration. Interestingly, anti-GcgR-induced α-cell hyperplasia can be uncoupled from β-cell regeneration after antibody clearance from the body. Importantly, we are able to show that anti-GcgR-induced β-cell regeneration is also observed in non-human primates. Furthermore, anti-GcgR and anti-CD3 combination therapy reverses diabetes and increases β-cell mass in a mouse model of autoimmune diabetes.
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11
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Nakamura A. Effects of Sodium-Glucose Co-Transporter-2 Inhibitors on Pancreatic β-Cell Mass and Function. Int J Mol Sci 2022; 23:ijms23095104. [PMID: 35563495 PMCID: PMC9105075 DOI: 10.3390/ijms23095104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 01/25/2023] Open
Abstract
Sodium-glucose co-transporter-2 inhibitors (SGLT2is) not only have antihyperglycemic effects and are associated with a low risk of hypoglycemia but also have protective effects in organs, including the heart and kidneys. The pathophysiology of diabetes involves chronic hyperglycemia, which causes excessive demands on pancreatic β-cells, ultimately leading to decreases in β-cell mass and function. Because SGLT2is ameliorate hyperglycemia without acting directly on β-cells, they are thought to prevent β-cell failure by reducing glucose overload in this cell type. Several studies have shown that treatment with an SGLT2i increases β-cell proliferation and/or reduces β-cell apoptosis, resulting in the preservation of β-cell mass in animal models of diabetes. In addition, many clinical trials have shown that that SGLT2is improve β-cell function in individuals with type 2 diabetes. In this review, the preclinical and clinical data regarding the effects of SGLT2is on pancreatic β-cell mass and function are summarized and the protective effect of SGLT2is in β-cells is discussed.
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Affiliation(s)
- Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
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12
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Kim MJ, Jeon JH. Recent Advances in Understanding Nrf2 Agonism and Its Potential Clinical Application to Metabolic and Inflammatory Diseases. Int J Mol Sci 2022; 23:ijms23052846. [PMID: 35269986 PMCID: PMC8910922 DOI: 10.3390/ijms23052846] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress is a major component of cell damage and cell fat, and as such, it occupies a central position in the pathogenesis of metabolic disease. Nuclear factor-erythroid-derived 2-related factor 2 (Nrf2), a key transcription factor that coordinates expression of genes encoding antioxidant and detoxifying enzymes, is regulated primarily by Kelch-like ECH-associated protein 1 (Keap1). However, involvement of the Keap1–Nrf2 pathway in tissue and organism homeostasis goes far beyond protection from cellular stress. In this review, we focus on evidence for Nrf2 pathway dysfunction during development of several metabolic/inflammatory disorders, including diabetes and diabetic complications, obesity, inflammatory bowel disease, and autoimmune diseases. We also review the beneficial role of current molecular Nrf2 agonists and summarize their use in ongoing clinical trials. We conclude that Nrf2 is a promising target for regulation of numerous diseases associated with oxidative stress and inflammation. However, more studies are needed to explore the role of Nrf2 in the pathogenesis of metabolic/inflammatory diseases and to review safety implications before therapeutic use in clinical practice.
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Affiliation(s)
- Min-Ji Kim
- Department of Endocrinology in Internal Medicine, Kyungpook National University Hospital, Daegu 41944, Korea;
| | - Jae-Han Jeon
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Chilgok Hospital, Daegu 41404, Korea
- Correspondence: ; Tel.: +82-(53)-200-3182; Fax: +82-(53)-200-3155
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13
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Transcriptional control of pancreatic β-cell identity and plasticity during the pathogenesis of type 2 diabetes. J Genet Genomics 2022; 49:316-328. [DOI: 10.1016/j.jgg.2022.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/23/2022] [Accepted: 03/06/2022] [Indexed: 11/21/2022]
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14
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Oberhauser L, Maechler P. Lipid-Induced Adaptations of the Pancreatic Beta-Cell to Glucotoxic Conditions Sustain Insulin Secretion. Int J Mol Sci 2021; 23:324. [PMID: 35008750 PMCID: PMC8745448 DOI: 10.3390/ijms23010324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 12/16/2022] Open
Abstract
Over the last decades, lipotoxicity and glucotoxicity emerged as established mechanisms participating in the pathophysiology of obesity-related type 2 diabetes in general, and in the loss of β-cell function in particular. However, these terms hold various potential biological processes, and it is not clear what precisely they refer to and to what extent they might be clinically relevant. In this review, we discuss the basis and the last advances of research regarding the role of free fatty acids, their metabolic intracellular pathways, and receptor-mediated signaling related to glucose-stimulated insulin secretion, as well as lipid-induced β-cell dysfunction. We also describe the role of chronically elevated glucose, namely, glucotoxicity, which promotes failure and dedifferentiation of the β cell. Glucolipotoxicity combines deleterious effects of exposures to both high glucose and free fatty acids, supposedly provoking synergistic defects on the β cell. Nevertheless, recent studies have highlighted the glycerolipid/free fatty acid cycle as a protective pathway mediating active storage and recruitment of lipids. Finally, we discuss the putative correspondence of the loss of functional β cells in type 2 diabetes with a natural, although accelerated, aging process.
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Affiliation(s)
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland;
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15
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Nakamura A, Omori K, Terauchi Y. Glucokinase activation or inactivation: Which will lead to the treatment of type 2 diabetes? Diabetes Obes Metab 2021; 23:2199-2206. [PMID: 34105236 DOI: 10.1111/dom.14459] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/24/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022]
Abstract
Glucokinase, which phosphorylates glucose to form glucose-6-phosphate, plays a critical role in regulating blood glucose levels. On the basis of data of glucokinase-knockout and transgenic mice and humans with glucokinase mutations, glucokinase was targeted for drug development aiming to augment its activity, and thereby reduce hyperglycaemia in patients with diabetes. In fact, various small molecule compounds have been developed and clinically tested as glucokinase activators. However, some have been discontinued because of efficacy and safety issues. One of these issues is loss of the drug's efficacy over time. This unsustained glycaemic efficacy may be associated with the excess glycolysis by glucokinase activation in pancreatic beta cells, resulting in beta-cell failure. Recently, we have shown that glucokinase haploinsufficiency ameliorated glucose intolerance by increasing beta-cell function and mass in a mouse model of diabetes. Given that a similar phenotype has been observed in glucokinase-activated beta cells and diabetic beta cells, glucokinase inactivation may be a new therapeutic target for type 2 diabetes.
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Affiliation(s)
- Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kazuno Omori
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
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16
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Chan JY, Bensellam M, Lin RCY, Liang C, Lee K, Jonas JC, Laybutt DR. Transcriptome analysis of islets from diabetes-resistant and diabetes-prone obese mice reveals novel gene regulatory networks involved in beta-cell compensation and failure. FASEB J 2021; 35:e21608. [PMID: 33977593 DOI: 10.1096/fj.202100009r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 03/23/2021] [Accepted: 04/05/2021] [Indexed: 01/02/2023]
Abstract
The mechanisms underpinning beta-cell compensation for obesity-associated insulin resistance and beta-cell failure in type 2 diabetes remain poorly understood. We used a large-scale strategy to determine the time-dependent transcriptomic changes in islets of diabetes-prone db/db and diabetes-resistant ob/ob mice at 6 and 16 weeks of age. Differentially expressed genes were subjected to cluster, gene ontology, pathway and gene set enrichment analyses. A distinctive gene expression pattern was observed in 16 week db/db islets in comparison to the other groups with alterations in transcriptional regulators of islet cell identity, upregulation of glucose/lipid metabolism, and various stress response genes, and downregulation of specific amino acid transport and metabolism genes. In contrast, ob/ob islets displayed a coordinated downregulation of metabolic and stress response genes at 6 weeks of age, suggestive of a preemptive reconfiguration in these islets to lower the threshold of metabolic activation in response to increased insulin demand thereby preserving beta-cell function and preventing cellular stress. In addition, amino acid transport and metabolism genes were upregulated in ob/ob islets, suggesting an important role of glutamate metabolism in beta-cell compensation. Gene set enrichment analysis of differentially expressed genes identified the enrichment of binding motifs for transcription factors, FOXO4, NFATC1, and MAZ. siRNA-mediated knockdown of these genes in MIN6 cells altered cell death, insulin secretion, and stress gene expression. In conclusion, these data revealed novel gene regulatory networks involved in beta-cell compensation and failure. Preemptive metabolic reconfiguration in diabetes-resistant islets may dampen metabolic activation and cellular stress during obesity.
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Affiliation(s)
- Jeng Yie Chan
- Garvan Institute of Medical Research, Sydney, NSW, Australia.,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Mohammed Bensellam
- Garvan Institute of Medical Research, Sydney, NSW, Australia.,Pôle D'endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Ruby C Y Lin
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Cassandra Liang
- Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Kailun Lee
- Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Jean-Christophe Jonas
- Pôle D'endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - D Ross Laybutt
- Garvan Institute of Medical Research, Sydney, NSW, Australia.,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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17
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Dhounchak S, Popp SK, Brown DJ, Laybutt DR, Biden TJ, Bornstein SR, Parish CR, Simeonovic CJ. Heparan sulfate proteoglycans in beta cells provide a critical link between endoplasmic reticulum stress, oxidative stress and type 2 diabetes. PLoS One 2021; 16:e0252607. [PMID: 34086738 PMCID: PMC8177513 DOI: 10.1371/journal.pone.0252607] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 05/19/2021] [Indexed: 12/24/2022] Open
Abstract
Heparan sulfate proteoglycans (HSPGs) consist of a core protein with side chains of the glycosaminoglycan heparan sulfate (HS). We have previously identified (i) the HSPGs syndecan-1 (SDC1), and collagen type XVIII (COL18) inside mouse and human islet beta cells, and (ii) a critical role for HS in beta cell survival and protection from reactive oxygen species (ROS). The objective of this study was to investigate whether endoplasmic reticulum (ER) stress contributes to oxidative stress and type 2 diabetes (T2D) by depleting beta cell HSPGs/HS. A rapid loss of intra-islet/beta cell HSPGs, HS and heparanase (HPSE, an HS-degrading enzyme) accompanied upregulation of islet ER stress gene expression in both young T2D-prone db/db and Akita Ins2WT/C96Y mice. In MIN6 beta cells, HSPGs, HS and HPSE were reduced following treatment with pharmacological inducers of ER stress (thapsigargin or tunicamycin). Treatment of young db/db mice with Tauroursodeoxycholic acid (TUDCA), a chemical protein folding chaperone that relieves ER stress, improved glycemic control and increased intra-islet HSPG/HS. In vitro, HS replacement with heparin (a highly sulfated HS analogue) significantly increased the survival of wild-type and db/db beta cells and restored their resistance to hydrogen peroxide-induced death. We conclude that ER stress inhibits the synthesis/maturation of HSPG core proteins which are essential for HS assembly, thereby exacerbating oxidative stress and promoting beta cell failure. Diminished intracellular HSPGs/HS represent a previously unrecognized critical link bridging ER stress, oxidative stress and beta cell failure in T2D.
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Affiliation(s)
- Sarita Dhounchak
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Sarah K. Popp
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Debra J. Brown
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - D. Ross Laybutt
- Garvan Institute of Medical Research, St Vincent’s Clinical School, The University of NSW (UNSW), Sydney, New South Wales, Australia
| | - Trevor J. Biden
- Garvan Institute of Medical Research, St Vincent’s Clinical School, The University of NSW (UNSW), Sydney, New South Wales, Australia
| | - Stefan R. Bornstein
- Department of Internal Medicine III, Carl Gustav Carus Medical School, Technical University of Dresden, Dresden, Germany
| | - Christopher R. Parish
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Charmaine J. Simeonovic
- Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail:
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18
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Chauhan S, Kerr A, Keogh B, Nolan S, Casey R, Adelfio A, Murphy N, Doherty A, Davis H, Wall AM, Khaldi N. An Artificial-Intelligence-Discovered Functional Ingredient, NRT_N0G5IJ, Derived from Pisum sativum, Decreases HbA1c in a Prediabetic Population. Nutrients 2021; 13:1635. [PMID: 34068000 PMCID: PMC8152294 DOI: 10.3390/nu13051635] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 12/20/2022] Open
Abstract
The prevalence of prediabetes is rapidly increasing, and this can lead to an increased risk for individuals to develop type 2 diabetes and associated diseases. Therefore, it is necessary to develop nutritional strategies to maintain healthy glucose levels and prevent glucose metabolism dysregulation in the general population. Functional ingredients offer great potential for the prevention of various health conditions, including blood glucose regulation, in a cost-effective manner. Using an artificial intelligence (AI) approach, a functional ingredient, NRT_N0G5IJ, was predicted and produced from Pisum sativum (pea) protein by hydrolysis and then validated. Treatment of human skeletal muscle cells with NRT_N0G5IJ significantly increased glucose uptake, indicating efficacy of this ingredient in vitro. When db/db diabetic mice were treated with NRT_N0G5IJ, we observed a significant reduction in glycated haemoglobin (HbA1c) levels and a concomitant benefit on fasting glucose. A pilot double-blinded, placebo controlled human trial in a population of healthy individuals with elevated HbA1c (5.6% to 6.4%) showed that HbA1c percentage was significantly reduced when NRT_N0G5IJ was supplemented in the diet over a 12-week period. Here, we provide evidence of an AI approach to discovery and demonstrate that a functional ingredient identified using this technology could be used as a supplement to maintain healthy glucose regulation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Audrey M. Wall
- Nuritas Ltd., Joshua Dawson House, Dawson St, Dublin 2, Ireland; (S.C.); (A.K.); (B.K.); (S.N.); (R.C.); (A.A.); (N.M.); (A.D.); (H.D.); (N.K.)
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19
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Honzawa N, Fujimoto K. The Plasticity of Pancreatic β-Cells. Metabolites 2021; 11:metabo11040218. [PMID: 33918379 PMCID: PMC8065544 DOI: 10.3390/metabo11040218] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/01/2021] [Accepted: 04/01/2021] [Indexed: 12/15/2022] Open
Abstract
Type 2 diabetes is caused by impaired insulin secretion and/or insulin resistance. Loss of pancreatic β-cell mass detected in human diabetic patients has been considered to be a major cause of impaired insulin secretion. Additionally, apoptosis is found in pancreatic β-cells; β-cell mass loss is induced when cell death exceeds proliferation. Recently, however, β-cell dedifferentiation to pancreatic endocrine progenitor cells and β-cell transdifferentiation to α-cell was reported in human islets, which led to a new underlying molecular mechanism. Hyperglycemia inhibits nuclear translocation and expression of forkhead box-O1 (FoxO1) and induces the expression of neurogenin-3 (Ngn3), which is required for the development and maintenance of pancreatic endocrine progenitor cells. This new hypothesis (Foxology) is attracting attention because it explains molecular mechanism(s) underlying β-cell plasticity. The lineage tracing technique revealed that the contribution of dedifferentiation is higher than that of β-cell apoptosis retaining to β-cell mass loss. In addition, islet cells transdifferentiate each other, such as transdifferentiation of pancreatic β-cell to α-cell and vice versa. Islet cells can exhibit plasticity, and they may have the ability to redifferentiate into any cell type. This review describes recent findings in the dedifferentiation and transdifferentiation of β-cells. We outline novel treatment(s) for diabetes targeting islet cell plasticity.
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Affiliation(s)
- Norikiyo Honzawa
- Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Jikei University School of Medicine, 3-25-8, Nishishinbashi, Minato-ku, Tokyo 105-8461, Japan;
| | - Kei Fujimoto
- Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Jikei University Kashiwa Hospital, 163-1, Kashiwashita, Kshiwa-shi, Chiba 277-8567, Japan
- Correspondence: ; Tel.: +81-04-7164-1111
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20
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Omori K, Nakamura A, Miyoshi H, Yamauchi Y, Kawata S, Takahashi K, Kitao N, Nomoto H, Kameda H, Cho KY, Terauchi Y, Atsumi T. Glucokinase Inactivation Paradoxically Ameliorates Glucose Intolerance by Increasing β-Cell Mass in db/db Mice. Diabetes 2021; 70:917-931. [PMID: 33608422 DOI: 10.2337/db20-0881] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 01/22/2021] [Indexed: 11/13/2022]
Abstract
Efficacy of glucokinase activation on glycemic control is limited to a short-term period. One reason might be related to excess glucose signaling by glucokinase activation toward β-cells. In this study, we investigated the effect of glucokinase haploinsufficiency on glucose tolerance as well as β-cell function and mass using a mouse model of type 2 diabetes. Our results showed that in db/db mice with glucokinase haploinsufficiency, glucose tolerance was ameliorated by augmented insulin secretion associated with the increase in β-cell mass when compared with db/db mice. Gene expression profiling and immunohistochemical and metabolomic analyses revealed that glucokinase haploinsufficiency in the islets of db/db mice was associated with lower expression of stress-related genes, greater expression of transcription factors involved in the maintenance and maturation of β-cell function, less mitochondrial damage, and a superior metabolic pattern. These effects of glucokinase haploinsufficiency could preserve β-cell mass under diabetic conditions. These findings verified our hypothesis that optimizing excess glucose signaling in β-cells by inhibiting glucokinase could prevent β-cell insufficiency, leading to improving glucose tolerance in diabetes status by preserving β-cell mass. Therefore, glucokinase inactivation in β-cells, paradoxically, could be a potential strategy for the treatment of type 2 diabetes.
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Affiliation(s)
- Kazuno Omori
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Akinobu Nakamura
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hideaki Miyoshi
- Division of Diabetes and Obesity, Faculty of Medicine and Graduate School of Medicine Hokkaido University, Sapporo, Japan
| | - Yuki Yamauchi
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Shinichiro Kawata
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kiyohiko Takahashi
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Naoyuki Kitao
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Nomoto
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiraku Kameda
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kyu Yong Cho
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
- Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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21
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Li B, Cheng Y, Yin Y, Xue J, Yu S, Gao J, Liu J, Zang L, Mu Y. Reversion of early- and late-stage β-cell dedifferentiation by human umbilical cord-derived mesenchymal stem cells in type 2 diabetic mice. Cytotherapy 2021; 23:510-520. [PMID: 33736932 DOI: 10.1016/j.jcyt.2021.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/11/2021] [Accepted: 01/20/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND AIMS The authors aimed to observe β-cell dedifferentiation in type 2 diabetes mellitus (T2DM) and investigate the reversal effect of umbilical cord-derived mesenchymal stem cells (UC-MSCs) on early- and late-stage β-cell dedifferentiation. METHODS In high-fat diet (HFD)/streptozotocin (STZ)-induced T2DM mice, the authors examined the predominant role of β-cell dedifferentiation over apoptosis in the development of T2DM and observed the reversion of β-cell dedifferentiation by UC-MSCs. Next, the authors used db/db mice to observe the progress of β-cell dedifferentiation from early to late stage, after which UC-MSC infusions of the same amount were performed in the early and late stages of dedifferentiation. Improvement in metabolic indices and restoration of β-cell dedifferentiation markers were examined. RESULTS In HFD/STZ-induced T2DM mice, the proportion of β-cell dedifferentiation was much greater than that of apoptosis, demonstrating that β-cell dedifferentiation was the predominant contributor to T2DM. UC-MSC infusions significantly improved glucose homeostasis and reversed β-cell dedifferentiation. In db/db mice, UC-MSC infusions in the early stage significantly improved glucose homeostasis and reversed β-cell dedifferentiation. In the late stage, UC-MSC infusions mildly improved glucose homeostasis and partially reversed β-cell dedifferentiation. Combining with other studies, the authors found that the reversal effect of UC-MSCs on β-cell dedifferentiation relied on the simultaneous relief of glucose and lipid metabolic disorders. CONCLUSIONS UC-MSC therapy is a promising strategy for reversing β-cell dedifferentiation in T2DM, and the reversal effect is greater in the early stage than in the late stage of β-cell dedifferentiation.
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Affiliation(s)
- Bing Li
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China
| | - Yu Cheng
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China
| | - Yaqi Yin
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China
| | - Jing Xue
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China
| | - Songyan Yu
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China
| | - Jieqing Gao
- Department of Endocrinology, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, China
| | - Jiejie Liu
- Department of Molecular Biology, Institute of Basic Medicine, School of Life Science, People's Liberation Army General Hospital, Beijing, China
| | - Li Zang
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China.
| | - Yiming Mu
- Department of Endocrinology, First Medical Center of People's Liberation Army General Hospital, Beijing, China.
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22
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Emerging Roles of Metallothioneins in Beta Cell Pathophysiology: Beyond and Above Metal Homeostasis and Antioxidant Response. BIOLOGY 2021; 10:biology10030176. [PMID: 33652748 PMCID: PMC7996892 DOI: 10.3390/biology10030176] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Defective insulin secretion by pancreatic beta cells is key for the development of type 2 diabetes but the precise mechanisms involved are poorly understood. Metallothioneins are metal binding proteins whose precise biological roles have not been fully characterized. Available evidence indicated that Metallothioneins are protective cellular effectors involved in heavy metal detoxification, metal ion homeostasis and antioxidant defense. This concept has however been challenged by emerging evidence in different medical research fields revealing novel negative roles of Metallothioneins, including in the context of diabetes. In this review, we gather and analyze the available knowledge regarding the complex roles of Metallothioneins in pancreatic beta cell biology and insulin secretion. We comprehensively analyze the evidence showing positive effects of Metallothioneins on beta cell function and survival as well as the emerging evidence revealing negative effects and discuss the possible underlying mechanisms. We expose in parallel findings from other medical research fields and underscore unsettled questions. Then, we propose some future research directions to improve knowledge in the field. Abstract Metallothioneins (MTs) are low molecular weight, cysteine-rich, metal-binding proteins whose precise biological roles have not been fully characterized. Existing evidence implicated MTs in heavy metal detoxification, metal ion homeostasis and antioxidant defense. MTs were thus categorized as protective effectors that contribute to cellular homeostasis and survival. This view has, however, been challenged by emerging evidence in different medical fields revealing novel pathophysiological roles of MTs, including inflammatory bowel disease, neurodegenerative disorders, carcinogenesis and diabetes. In the present focused review, we discuss the evidence for the role of MTs in pancreatic beta-cell biology and insulin secretion. We highlight the pattern of specific isoforms of MT gene expression in rodents and human beta-cells. We then discuss the mechanisms involved in the regulation of MTs in islets under physiological and pathological conditions, particularly type 2 diabetes, and analyze the evidence revealing adaptive and negative roles of MTs in beta-cells and the potential mechanisms involved. Finally, we underscore the unsettled questions in the field and propose some future research directions.
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23
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Guay C, Jacovetti C, Bayazit MB, Brozzi F, Rodriguez-Trejo A, Wu K, Regazzi R. Roles of Noncoding RNAs in Islet Biology. Compr Physiol 2020; 10:893-932. [PMID: 32941685 DOI: 10.1002/cphy.c190032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The discovery that most mammalian genome sequences are transcribed to ribonucleic acids (RNA) has revolutionized our understanding of the mechanisms governing key cellular processes and of the causes of human diseases, including diabetes mellitus. Pancreatic islet cells were found to contain thousands of noncoding RNAs (ncRNAs), including micro-RNAs (miRNAs), PIWI-associated RNAs, small nucleolar RNAs, tRNA-derived fragments, long non-coding RNAs, and circular RNAs. While the involvement of miRNAs in islet function and in the etiology of diabetes is now well documented, there is emerging evidence indicating that other classes of ncRNAs are also participating in different aspects of islet physiology. The aim of this article will be to provide a comprehensive and updated view of the studies carried out in human samples and rodent models over the past 15 years on the role of ncRNAs in the control of α- and β-cell development and function and to highlight the recent discoveries in the field. We not only describe the role of ncRNAs in the control of insulin and glucagon secretion but also address the contribution of these regulatory molecules in the proliferation and survival of islet cells under physiological and pathological conditions. It is now well established that most cells release part of their ncRNAs inside small extracellular vesicles, allowing the delivery of genetic material to neighboring or distantly located target cells. The role of these secreted RNAs in cell-to-cell communication between β-cells and other metabolic tissues as well as their potential use as diabetes biomarkers will be discussed. © 2020 American Physiological Society. Compr Physiol 10:893-932, 2020.
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Affiliation(s)
- Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Cécile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Mustafa Bilal Bayazit
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Flora Brozzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Adriana Rodriguez-Trejo
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Kejing Wu
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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24
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Zhang J, Liu F. The De-, Re-, and trans-differentiation of β-cells: Regulation and function. Semin Cell Dev Biol 2020; 103:68-75. [DOI: 10.1016/j.semcdb.2020.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/09/2019] [Accepted: 01/03/2020] [Indexed: 12/11/2022]
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25
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Hu Z, Nizzero S, Goel S, Hinkle LE, Wu X, Li C, Ferrari M, Shen H. Molecular targeting of FATP4 transporter for oral delivery of therapeutic peptide. SCIENCE ADVANCES 2020; 6:eaba0145. [PMID: 32270048 PMCID: PMC7112756 DOI: 10.1126/sciadv.aba0145] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/09/2020] [Indexed: 06/11/2023]
Abstract
Low oral bioavailability of peptide drugs has limited their application to parenteral administration, which suffers from poor patient compliance. Here, we show that molecular targeting of the FATP4 transporter is an effective approach to specifically transport long-chain fatty acid (LCFA)-conjugated peptides across the enterocytic membrane and, thus, enables oral delivery of drug peptides. We packaged LCFA-conjugated exendin-4 (LCFA-Ex4) into liposomes and coated with chitosan nanoparticles to form an orally deliverable Ex4 (OraEx4). OraEx4 protected LCFA-Ex4 from damage by the gastric fluid and released LCFA-Ex4 in the intestinal cavity, where LCFA-Ex4 was transported across the enterocyte membrane by the FAPT4 transporter. OraEx4 had a high bioavailability of 24.8% with respect to subcutaneous injection and exhibited a substantial hypoglycemic effect in murine models of diabetes mellitus. Thus, molecular targeting of the FATP4 transporter enhances oral absorption of therapeutic peptides and provides a platform for oral peptide drug development.
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Affiliation(s)
- Zhenhua Hu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Sara Nizzero
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Shreya Goel
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Louis E. Hinkle
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Xiaoyan Wu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Pediatric Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chao Li
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Mauro Ferrari
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Haifa Shen
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA
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26
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Weir GC. Glucolipotoxicity, β-Cells, and Diabetes: The Emperor Has No Clothes. Diabetes 2020; 69:273-278. [PMID: 31519699 PMCID: PMC7034184 DOI: 10.2337/db19-0138] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/08/2019] [Indexed: 12/21/2022]
Abstract
Reduction of β-cell mass and function is central to the pathogenesis of type 2 diabetes. The terms glucotoxicity, lipotoxicity, and glucolipotoxicity are used to describe potentially responsible processes. The premise is that chronically elevated glucose levels are toxic to β-cells, that elevated lipid levels in the form of circulating free fatty acids (FFA) also have toxic effects, and that the combination of the two, glucolipotoxicity, is particularly harmful. Much work has shown that high concentrations of FFA can be very damaging to β-cells when used for in vitro experiments, and when infused in large amounts in humans and rodents they produce suppression of insulin secretion. The purpose of this Perspective is to raise doubts about whether the FFA levels found in real-life situations are ever high enough to cause problems. Evidence supporting the importance of glucotoxicity is strong because there is such a tight correlation between defective insulin secretion and rising glucose levels. However, there is virtually no convincing evidence that the alterations in FFA levels occurring during progression to diabetes are pathogenic. Thus, the terms lipotoxicity and glucolipotoxicity should be used with great caution, if at all, because evidence supporting their importance has not yet emerged.
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Affiliation(s)
- Gordon C Weir
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, MA
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27
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Weir GC, Gaglia J, Bonner-Weir S. Inadequate β-cell mass is essential for the pathogenesis of type 2 diabetes. Lancet Diabetes Endocrinol 2020; 8:249-256. [PMID: 32006519 PMCID: PMC7098467 DOI: 10.1016/s2213-8587(20)30022-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/19/2019] [Accepted: 12/03/2019] [Indexed: 12/16/2022]
Abstract
For patients with type 1 diabetes, it is accepted among the scientific community that there is a marked reduction in β-cell mass; however, with type 2 diabetes, there is disagreement as to whether this reduction in mass occurs in every case. Some have argued that β-cell mass in some patients with type 2 diabetes is normal and that the cause of the hyperglycaemia in these patients is a functional abnormality of insulin secretion. In this Personal View, we argue that a deficient β-cell mass is essential for the development of type 2 diabetes. The main point is that there are enormous (≥10 fold) variations in insulin sensitivity and insulin secretion in the general population, with a very close correlation between these two factors for any individual. Although β-cell mass cannot be accurately measured in living patients, it is highly likely that it too is highly correlated with insulin sensitivity and secretion. Thus, our argument is that a person with type 2 diabetes can have a β-cell mass that is the same as a person without type 2 diabetes, but because they are insulin resistant, the mass is inadequate and responsible for their diabetes. Because the abnormal insulin secretion of diabetes is caused by dysglycaemia and can be largely reversed with glycaemic control, it is a less serious problem than the reduction in β-cell mass, which is far more difficult to restore.
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Affiliation(s)
- Gordon C Weir
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA.
| | - Jason Gaglia
- Section on Immunobiology, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Susan Bonner-Weir
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
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28
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Whitticar NB, Nunemaker CS. Reducing Glucokinase Activity to Enhance Insulin Secretion: A Counterintuitive Theory to Preserve Cellular Function and Glucose Homeostasis. Front Endocrinol (Lausanne) 2020; 11:378. [PMID: 32582035 PMCID: PMC7296051 DOI: 10.3389/fendo.2020.00378] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/12/2020] [Indexed: 12/21/2022] Open
Abstract
Pancreatic beta-cells are the only cells in the body that can synthesize and secrete insulin. Through the process of glucose-stimulated insulin secretion, beta-cells release insulin into circulation, stimulating GLUT4-dependent glucose uptake into peripheral tissue. Insulin is normally secreted in pulses that promote signaling at the liver. Long before type 2 diabetes is diagnosed, beta-cells become oversensitive to glucose, causing impaired pulsatility and overstimulation in fasting levels of glucose. The resulting hypersecretion of insulin can cause poor insulin signaling and clearance at the liver, leading to hyperinsulinemia and insulin resistance. Continued overactivity can eventually lead to beta-cell exhaustion and failure at which point type 2 diabetes begins. To prevent or reverse the negative effects of overstimulation, beta-cell activity can be reduced. Clinical studies have revealed the potential of beta-cell rest to reverse new cases of diabetes, but treatments lack durable benefits. In this perspective, we propose an intervention that reduces overactive glucokinase activity in the beta-cell. Glucokinase is known as the glucose sensor of the beta-cell due to its high control over insulin secretion. Therefore, glycolytic overactivity may be responsible for hyperinsulinemia early in the disease and can be reduced to restore normal stimulus-secretion coupling. We have previously reported that reducing glucokinase activity in prediabetic mouse islets can restore pulsatility and enhance insulin secretion. Building on this counterintuitive finding, we review the importance of pulsatile insulin secretion and highlight how normalizing glucose sensing in the beta cell during prediabetic hyperinsulinemia may restore pulsatility and improve glucose homeostasis.
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Affiliation(s)
- Nicholas B. Whitticar
- Translational Biomedical Sciences Program, Graduate College, Ohio University, Athens, OH, United States
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens OH, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
| | - Craig S. Nunemaker
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens OH, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
- *Correspondence: Craig S. Nunemaker
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29
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Wojnarowicz PM, Lima E Silva R, Ohnaka M, Lee SB, Chin Y, Kulukian A, Chang SH, Desai B, Garcia Escolano M, Shah R, Garcia-Cao M, Xu S, Kadam R, Goldgur Y, Miller MA, Ouerfelli O, Yang G, Arakawa T, Albanese SK, Garland WA, Stoller G, Chaudhary J, Norton L, Soni RK, Philip J, Hendrickson RC, Iavarone A, Dannenberg AJ, Chodera JD, Pavletich N, Lasorella A, Campochiaro PA, Benezra R. A Small-Molecule Pan-Id Antagonist Inhibits Pathologic Ocular Neovascularization. Cell Rep 2019; 29:62-75.e7. [PMID: 31577956 PMCID: PMC6896334 DOI: 10.1016/j.celrep.2019.08.073] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 08/09/2019] [Accepted: 08/23/2019] [Indexed: 02/01/2023] Open
Abstract
Id helix-loop-helix (HLH) proteins (Id1-4) bind E protein bHLH transcription factors, preventing them from forming active transcription complexes that drive changes in cell states. Id proteins are primarily expressed during development to inhibit differentiation, but they become re-expressed in adult tissues in diseases of the vasculature and cancer. We show that the genetic loss of Id1/Id3 reduces ocular neovascularization in mouse models of wet age-related macular degeneration (AMD) and retinopathy of prematurity (ROP). An in silico screen identifies AGX51, a small-molecule Id antagonist. AGX51 inhibits the Id1-E47 interaction, leading to ubiquitin-mediated degradation of Ids, cell growth arrest, and reduced viability. AGX51 is well-tolerated in mice and phenocopies the genetic loss of Id expression in AMD and ROP models by inhibiting retinal neovascularization. Thus, AGX51 is a first-in-class compound that antagonizes an interaction formerly considered undruggable and that may have utility in the management of multiple diseases.
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Affiliation(s)
- Paulina M Wojnarowicz
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Raquel Lima E Silva
- Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Masayuki Ohnaka
- Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Sang Bae Lee
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA
| | - Yvette Chin
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anita Kulukian
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Sung-Hee Chang
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Bina Desai
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Marta Garcia Escolano
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Riddhi Shah
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Marta Garcia-Cao
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Sijia Xu
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Rashmi Kadam
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yehuda Goldgur
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Meredith A Miller
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ouathek Ouerfelli
- Organic Synthesis Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Guangli Yang
- Organic Synthesis Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Tsutomu Arakawa
- Alliance Protein Laboratories, a Division of KBI Biopharma, San Diego, CA 92121, USA
| | - Steven K Albanese
- Computational Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | | | - Glenn Stoller
- Ophthalmic Consultants of Long Island, Lynbrook, NY 11563, USA
| | - Jaideep Chaudhary
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA
| | - Larry Norton
- Evelyn H. Lauder Breast Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Rajesh Kumar Soni
- Proteomics & Microchemistry Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - John Philip
- Proteomics & Microchemistry Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ronald C Hendrickson
- Proteomics & Microchemistry Core Facility, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Antonio Iavarone
- Department of Neurology, Department of Pathology, Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA
| | - Andrew J Dannenberg
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - John D Chodera
- Computational Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Nikola Pavletich
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anna Lasorella
- Department of Pediatrics, Department of Pathology, Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA
| | - Peter A Campochiaro
- Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Robert Benezra
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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30
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Ibarra Urizar A, Prause M, Wortham M, Sui Y, Thams P, Sander M, Christensen GL, Billestrup N. Beta-cell dysfunction induced by non-cytotoxic concentrations of Interleukin-1β is associated with changes in expression of beta-cell maturity genes and associated histone modifications. Mol Cell Endocrinol 2019; 496:110524. [PMID: 31362031 DOI: 10.1016/j.mce.2019.110524] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/12/2019] [Accepted: 07/24/2019] [Indexed: 10/26/2022]
Abstract
Decreased insulin secretory capacity in Type 2 diabetes mellitus is associated with beta-cell dedifferentiation and inflammation. We hypothesize that prolonged exposure of beta-cells to low concentrations of IL-1β induce beta-cell dedifferentiation characterized by impaired glucose-stimulated insulin secretion, reduced expression of key beta-cell genes and changes in histone modifications at gene loci known to affect beta-cell function. Ten days exposure to IL-1β at non-cytotoxic concentrations reduced insulin secretion and beta-cell proliferation and decreased expression of key beta-cell identity genes, including MafA and Ucn3 and decreased H3K27ac at the gene loci, suggesting that inflammatory cytokines directly affects the epigenome. Following removal of IL-1β, beta-cell function was normalized and mRNA expression of beta-cell identity genes, such as insulin and Ucn3 returned to pre-stimulation levels. Our findings indicate that prolonged exposure to low concentrations of IL-1β induces epigenetic changes associated with loss of beta-cell identity as observed in Type 2 diabetes.
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Affiliation(s)
- Adriana Ibarra Urizar
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Michala Prause
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Matthew Wortham
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center and Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yinghui Sui
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center and Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Peter Thams
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Maike Sander
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center and Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Gitte Lund Christensen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark; Department of Biomedical Laboratory Science, Metropolitan University College, Copenhagen, 2200, Denmark
| | - Nils Billestrup
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark; Lead Contact Nils Billestrup, Department of Biomedical Science, University of Copenhagen, Copenhagen, 2200, Denmark.
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31
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Eitah HE, Maklad YA, Abdelkader NF, Gamal El Din AA, Badawi MA, Kenawy SA. Modulating impacts of quercetin/sitagliptin combination on streptozotocin-induced diabetes mellitus in rats. Toxicol Appl Pharmacol 2018; 365:30-40. [PMID: 30576699 DOI: 10.1016/j.taap.2018.12.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND Since many diabetic patients require combination therapy, the use of herbal remedies with anti-diabetic activity represents a vital option in diabetes mellitus (DM) management. It has been reported that quercetin has hypoglycemic alongside anti-inflammatory and antioxidant activities. AIM The present study aimed to investigate the effectiveness of combining quercetin with sitagliptin; a selective dipeptidyl peptidase-IV (DPP-IV) inhibitor, in the management of streptozotocin (STZ)-induced diabetic rats. METHODS DM was induced by a single injection of STZ (45 mg/kg, i.p.) in male adult albino Wistar rats. Diabetic rats were orally treated with sitagliptin (70 mg/kg), quercetin (50 mg/kg) or their combination daily for three consecutive weeks. Serum levels of glucose, C-peptide, total cholesterol, triglycerides, malondialdehyde (MDA), superoxide dismutase, (SOD), reduced glutathione (GSH), tumor necrosis factor alpha, (TNF-α), nuclear factor kappa-B, (NF-κB) and adiponectin were estimated. In addition, histopathological, morphometrical and immunohistochemical examinations of pancreatic tissues were conducted. RESULTS The combined administration of quercetin and sitagliptin normalized serum C-peptide, MDA, and significantly increased SOD, GSH and decreased NF-κB more than sitagliptin alone. Moreover, this combination normalized Islet number, β-cells' number, area and perimeter alongside restoring the immunostaining intensity of β-cells. CONCLUSION Our results suggest the use of quercetin/sitagliptin combination for treating DM based on the observed improvements in glycemic control, metabolic profile, oxidative and inflammatory status, islet structure as well as β-cells function compared with either treatment alone.
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Affiliation(s)
- Hebatollah E Eitah
- Medicinal and Pharmaceutical Chemistry Department, Pharmacology Group, National Research Centre, Dokki, Giza, Egypt.
| | - Yousreya A Maklad
- Medicinal and Pharmaceutical Chemistry Department, Pharmacology Group, National Research Centre, Dokki, Giza, Egypt
| | - Noha F Abdelkader
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Cairo University, Giza, Egypt
| | | | - Manal A Badawi
- Pathology Department, National Research Centre, Dokki, Giza, Egypt
| | - Sanaa A Kenawy
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Cairo University, Giza, Egypt
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Sanchez-Parra C, Jacovetti C, Dumortier O, Lee K, Peyot ML, Guay C, Prentki M, Laybutt DR, Van Obberghen E, Regazzi R. Contribution of the Long Noncoding RNA H19 to β-Cell Mass Expansion in Neonatal and Adult Rodents. Diabetes 2018; 67:2254-2267. [PMID: 30115652 DOI: 10.2337/db18-0201] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 08/03/2018] [Indexed: 11/13/2022]
Abstract
Pancreatic β-cell expansion throughout the neonatal period is essential to generate the appropriate mass of insulin-secreting cells required to maintain blood glucose homeostasis later in life. Hence, defects in this process can predispose to diabetes development during adulthood. Global profiling of transcripts in pancreatic islets of newborn and adult rats revealed that the transcription factor E2F1 controls expression of the long noncoding RNA H19, which is profoundly downregulated during the postnatal period. H19 silencing decreased β-cell expansion in newborns, whereas its re-expression promoted proliferation of β-cells in adults via a mechanism involving the microRNA let-7 and the activation of Akt. The offspring of rats fed a low-protein diet during gestation and lactation display a small β-cell mass and an increased risk of developing diabetes during adulthood. We found that the islets of newborn rats born to dams fed a low-protein diet express lower levels of H19 than those born to dams that did not eat a low-protein diet. Moreover, we observed that H19 expression increases in islets of obese mice under conditions of increased insulin demand. Our data suggest that the long noncoding RNA H19 plays an important role in postnatal β-cell mass expansion in rats and contributes to the mechanisms compensating for insulin resistance in obesity.
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Affiliation(s)
- Clara Sanchez-Parra
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Cécile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Olivier Dumortier
- University Côte d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging, Nice, France
| | - Kailun Lee
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Marie-Line Peyot
- Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier Universitaire de Montréal, Montréal, Québec, Canada
| | - Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Marc Prentki
- Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier Universitaire de Montréal, Montréal, Québec, Canada
| | - D Ross Laybutt
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Emmanuel Van Obberghen
- University Côte d'Azur, Centre Hospitalier Universitaire, INSERM, CNRS, Institute for Research on Cancer and Aging, Nice, France
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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Liu M, Weiss MA, Arunagiri A, Yong J, Rege N, Sun J, Haataja L, Kaufman RJ, Arvan P. Biosynthesis, structure, and folding of the insulin precursor protein. Diabetes Obes Metab 2018; 20 Suppl 2:28-50. [PMID: 30230185 PMCID: PMC6463291 DOI: 10.1111/dom.13378] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Insulin synthesis in pancreatic β-cells is initiated as preproinsulin. Prevailing glucose concentrations, which oscillate pre- and postprandially, exert major dynamic variation in preproinsulin biosynthesis. Accompanying upregulated translation of the insulin precursor includes elements of the endoplasmic reticulum (ER) translocation apparatus linked to successful orientation of the signal peptide, translocation and signal peptide cleavage of preproinsulin-all of which are necessary to initiate the pathway of proper proinsulin folding. Evolutionary pressures on the primary structure of proinsulin itself have preserved the efficiency of folding ("foldability"), and remarkably, these evolutionary pressures are distinct from those protecting the ultimate biological activity of insulin. Proinsulin foldability is manifest in the ER, in which the local environment is designed to assist in the overall load of proinsulin folding and to favour its disulphide bond formation (while limiting misfolding), all of which is closely tuned to ER stress response pathways that have complex (beneficial, as well as potentially damaging) effects on pancreatic β-cells. Proinsulin misfolding may occur as a consequence of exuberant proinsulin biosynthetic load in the ER, proinsulin coding sequence mutations, or genetic predispositions that lead to an altered ER folding environment. Proinsulin misfolding is a phenotype that is very much linked to deficient insulin production and diabetes, as is seen in a variety of contexts: rodent models bearing proinsulin-misfolding mutants, human patients with Mutant INS-gene-induced Diabetes of Youth (MIDY), animal models and human patients bearing mutations in critical ER resident proteins, and, quite possibly, in more common variety type 2 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202 IN USA
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Jing Yong
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Nischay Rege
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
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Bensellam M, Jonas JC, Laybutt DR. Mechanisms of β-cell dedifferentiation in diabetes: recent findings and future research directions. J Endocrinol 2018; 236:R109-R143. [PMID: 29203573 DOI: 10.1530/joe-17-0516] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022]
Abstract
Like all the cells of an organism, pancreatic β-cells originate from embryonic stem cells through a complex cellular process termed differentiation. Differentiation involves the coordinated and tightly controlled activation/repression of specific effectors and gene clusters in a time-dependent fashion thereby giving rise to particular morphological and functional cellular features. Interestingly, cellular differentiation is not a unidirectional process. Indeed, growing evidence suggests that under certain conditions, mature β-cells can lose, to various degrees, their differentiated phenotype and cellular identity and regress to a less differentiated or a precursor-like state. This concept is termed dedifferentiation and has been proposed, besides cell death, as a contributing factor to the loss of functional β-cell mass in diabetes. β-cell dedifferentiation involves: (1) the downregulation of β-cell-enriched genes, including key transcription factors, insulin, glucose metabolism genes, protein processing and secretory pathway genes; (2) the concomitant upregulation of genes suppressed or expressed at very low levels in normal β-cells, the β-cell forbidden genes; and (3) the likely upregulation of progenitor cell genes. These alterations lead to phenotypic reconfiguration of β-cells and ultimately defective insulin secretion. While the major role of glucotoxicity in β-cell dedifferentiation is well established, the precise mechanisms involved are still under investigation. This review highlights the identified molecular mechanisms implicated in β-cell dedifferentiation including oxidative stress, endoplasmic reticulum (ER) stress, inflammation and hypoxia. It discusses the role of Foxo1, Myc and inhibitor of differentiation proteins and underscores the emerging role of non-coding RNAs. Finally, it proposes a novel hypothesis of β-cell dedifferentiation as a potential adaptive mechanism to escape cell death under stress conditions.
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Affiliation(s)
- Mohammed Bensellam
- Garvan Institute of Medical ResearchSydney, New South Wales, Australia
- Université Catholique de LouvainInstitut de Recherche Expérimentale et Clinique, Pôle d'Endocrinologie, Diabète et Nutrition, Brussels, Belgium
| | - Jean-Christophe Jonas
- Université Catholique de LouvainInstitut de Recherche Expérimentale et Clinique, Pôle d'Endocrinologie, Diabète et Nutrition, Brussels, Belgium
| | - D Ross Laybutt
- Garvan Institute of Medical ResearchSydney, New South Wales, Australia
- St Vincent's Clinical SchoolUNSW Sydney, Sydney, New South Wales, Australia
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35
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Stoll L, Sobel J, Rodriguez-Trejo A, Guay C, Lee K, Venø MT, Kjems J, Laybutt DR, Regazzi R. Circular RNAs as novel regulators of β-cell functions in normal and disease conditions. Mol Metab 2018; 9:69-83. [PMID: 29396373 PMCID: PMC5870096 DOI: 10.1016/j.molmet.2018.01.010] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE There is strong evidence for an involvement of different classes of non-coding RNAs, including microRNAs and long non-coding RNAs, in the regulation of β-cell activities and in diabetes development. Circular RNAs were recently discovered to constitute a substantial fraction of the mammalian transcriptome but the contribution of these non-coding RNAs in physiological and disease processes remains largely unknown. The goal of this study was to identify the circular RNAs expressed in pancreatic islets and to elucidate their possible role in the control of β-cells functions. METHODS We used a microarray approach to identify circular RNAs expressed in human islets and searched their orthologues in RNA sequencing data from mouse islets. We then measured the level of four selected circular RNAs in the islets of different Type 1 and Type 2 diabetes models and analyzed the role of these circular transcripts in the regulation of insulin secretion, β-cell proliferation, and apoptosis. RESULTS We identified thousands of circular RNAs expressed in human pancreatic islets, 497 of which were conserved in mouse islets. The level of two of these circular transcripts, circHIPK3 and ciRS-7/CDR1as, was found to be reduced in the islets of diabetic db/db mice. Mimicking this decrease in the islets of wild type animals resulted in impaired insulin secretion, reduced β-cell proliferation, and survival. ciRS-7/CDR1as has been previously proposed to function by blocking miR-7. Transcriptomic analysis revealed that circHIPK3 acts by sequestering a group of microRNAs, including miR-124-3p and miR-338-3p, and by regulating the expression of key β-cell genes, such as Slc2a2, Akt1, and Mtpn. CONCLUSIONS Our findings point to circular RNAs as novel regulators of β-cell activities and suggest an involvement of this novel class of non-coding RNAs in β-cell dysfunction under diabetic conditions.
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Affiliation(s)
- Lisa Stoll
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland
| | - Jonathan Sobel
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland
| | | | - Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland
| | - Kailun Lee
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Morten Trillingsgaard Venø
- Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Jørgen Kjems
- Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - D Ross Laybutt
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland.
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Faita F, Di Lascio N, Rossi C, Kusmic C, Solini A. Ultrasonographic Characterization of the db/db Mouse: An Animal Model of Metabolic Abnormalities. J Diabetes Res 2018; 2018:4561309. [PMID: 29707583 PMCID: PMC5863337 DOI: 10.1155/2018/4561309] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/13/2017] [Accepted: 01/04/2018] [Indexed: 12/18/2022] Open
Abstract
The availability of an animal model able to reliably mirror organ damage occurring in metabolic diseases is an urgent need. These models, mostly rodents, have not been fully characterized in terms of cardiovascular, renal, and hepatic ultrasound parameters, and only sparse values can be found in literature. Aim of this paper is to provide a detailed, noninvasive description of the heart, vessels, liver, and kidneys of the db/db mouse by ultrasound imaging. Sixteen wild type and thirty-four db/db male mice (11-week-old) were studied. State-of-the-art ultrasound technology was used to acquire images of cardiovascular, renal, and hepatic districts. A set of parameters describing function of the selected organs was evaluated. db/db mice are characterized by systolic and diastolic dysfunction, confirmed by strain analysis. Abdominal aortic and carotid stiffness do not seem to be increased in diabetic rodents; furthermore, they are characterized by a smaller mean diameter for both vessels. Renal microcirculation is significantly compromised, while liver steatosis is only slightly higher in db/db mice than in controls. We offer here for the first time an in vivo detailed ultrasonographic characterization of the db/db mouse, providing a useful tool for a thoughtful choice of the right rodent model for any experimental design.
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MESH Headings
- Animals
- Aorta, Abdominal/diagnostic imaging
- Aorta, Abdominal/physiopathology
- Blood Glucose/metabolism
- Carotid Artery, Common/diagnostic imaging
- Carotid Artery, Common/physiopathology
- Diabetes Mellitus/blood
- Diabetes Mellitus/diagnostic imaging
- Diabetes Mellitus/genetics
- Diabetes Mellitus/physiopathology
- Disease Models, Animal
- Echocardiography, Doppler, Pulsed
- Genetic Predisposition to Disease
- Heart/diagnostic imaging
- Heart/physiopathology
- Lipids/blood
- Liver/diagnostic imaging
- Liver/physiopathology
- Male
- Mice, Inbred C57BL
- Microcirculation
- Perfusion Imaging/methods
- Phenotype
- Predictive Value of Tests
- Renal Artery/diagnostic imaging
- Renal Artery/physiopathology
- Renal Circulation
- Ultrasonography, Doppler, Pulsed
- Vascular Stiffness
- Ventricular Function, Left
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Affiliation(s)
- Francesco Faita
- Institute of Clinical Physiology, Italian National Research Council, Pisa, Italy
| | - Nicole Di Lascio
- Institute of Clinical Physiology, Italian National Research Council, Pisa, Italy
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Chiara Rossi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Claudia Kusmic
- Institute of Clinical Physiology, Italian National Research Council, Pisa, Italy
| | - Anna Solini
- Department of Surgical, Medical, Molecular, and Critical Area Pathology, University of Pisa, Pisa, Italy
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Jurczak MJ, Saini S, Ioja S, Costa DK, Udeh N, Zhao X, Whaley JM, Kibbey RG. SGLT2 knockout prevents hyperglycemia and is associated with reduced pancreatic β-cell death in genetically obese mice. Islets 2018; 10:181-189. [PMID: 30118626 PMCID: PMC6284495 DOI: 10.1080/19382014.2018.1503027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Inhibition of the sodium-glucose co-transporter type 2 (SGLT2) has received growing acceptance as a novel, safe and effective means to improve glycemic control in patients with type 2 diabetes. Inhibition of SGLT2 lowers the renal glucose threshold and reduces plasma glucose by promoting glucose excretion in urine. Both animal studies and clinical trials in man suggest that SGLT2 inhibition has the potential to improve pancreatic β-cell function by reducing glucose toxicity. However, there is limited data exploring how reducing glucotoxicity via SGLT2 inhibition affects rates of β-cell proliferation and death throughout life in the context of insulin resistance and type 2 diabetes. SGLT2-/- mice were backcrossed to the db/db strain to produce littermate control db/db-SGLT2+/+ and experimental db/db-SGLT2-/- mice. Mice were euthanized at 5, 12 and 20 weeks of age to collect plasma for glucose, insulin, lipid and cytokine measures, and pancreata for histological analysis including determination of β-cell mass and rates of proliferation and death. SGLT2 deletion in db/db mice reduced plasma glucose as early as 5 weeks of age and continued throughout life without changes in plasma lipids or cytokines. Reduced plasma glucose levels occurred in parallel with an increase in the relative β-cell volume and reduced frequency of β-cell death, and no apparent change in rates of β-cell proliferation. These data add to a growing body of evidence demonstrating that improved glycemic control achieved through SGLT2 inhibition can preserve β-cell function and endogenous insulin secretion by reducing glucose toxicity and rates of β-cell death.
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Affiliation(s)
- Michael J. Jurczak
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Saumya Saini
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Simona Ioja
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Diana K. Costa
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Nnamdi Udeh
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Xiaojian Zhao
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Jean M. Whaley
- Metabolic Diseases Biology, Bristol-Myers Squibb Research and Development, Princeton, NJ, USA
| | - Richard G. Kibbey
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
- Departments of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
- CONTACT Richard G. Kibbey Internal Medicine-Endocrinology, Yale University School of Medicine, TAC S269, P.O. Box 9812, New Haven, CT 06536-8012; Michael J. Jurczak Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh School of Medicine, 200 Lothrop Street, BST W1060, Pittsburgh, PA 15261
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Endoplasmic Reticulum Stress and Obesity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 960:261-276. [DOI: 10.1007/978-3-319-48382-5_11] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Axelsson AS, Mahdi T, Nenonen HA, Singh T, Hänzelmann S, Wendt A, Bagge A, Reinbothe TM, Millstein J, Yang X, Zhang B, Gusmao EG, Shu L, Szabat M, Tang Y, Wang J, Salö S, Eliasson L, Artner I, Fex M, Johnson JD, Wollheim CB, Derry JMJ, Mecham B, Spégel P, Mulder H, Costa IG, Zhang E, Rosengren AH. Sox5 regulates beta-cell phenotype and is reduced in type 2 diabetes. Nat Commun 2017; 8:15652. [PMID: 28585545 PMCID: PMC5467166 DOI: 10.1038/ncomms15652] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 04/10/2017] [Indexed: 01/09/2023] Open
Abstract
Type 2 diabetes (T2D) is characterized by insulin resistance and impaired insulin secretion, but the mechanisms underlying insulin secretion failure are not completely understood. Here, we show that a set of co-expressed genes, which is enriched for genes with islet-selective open chromatin, is associated with T2D. These genes are perturbed in T2D and have a similar expression pattern to that of dedifferentiated islets. We identify Sox5 as a regulator of the module. Sox5 knockdown induces gene expression changes similar to those observed in T2D and diabetic animals and has profound effects on insulin secretion, including reduced depolarization-evoked Ca2+-influx and β-cell exocytosis. SOX5 overexpression reverses the expression perturbations observed in a mouse model of T2D, increases the expression of key β-cell genes and improves glucose-stimulated insulin secretion in human islets from donors with T2D. We suggest that human islets in T2D display changes reminiscent of dedifferentiation and highlight SOX5 as a regulator of β-cell phenotype and function.
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Affiliation(s)
- A S Axelsson
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - T Mahdi
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Medical Research Center, Hawler Medical University, 44001 Erbil, Iraq
| | - H A Nenonen
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - T Singh
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - S Hänzelmann
- Institute of Biomedical Engineering, RWTH Aachen University Hospital, Pauwelstr 19, 52074 Aachen, Germany
| | - A Wendt
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - A Bagge
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - T M Reinbothe
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - J Millstein
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA
| | - X Yang
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA.,Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Dr East, Los Angeles, California 90095, USA
| | - B Zhang
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA.,Department of Genetics and Genomic Sciences, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, New York 10029, USA
| | - E G Gusmao
- Institute of Biomedical Engineering, RWTH Aachen University Hospital, Pauwelstr 19, 52074 Aachen, Germany
| | - L Shu
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Dr East, Los Angeles, California 90095, USA
| | - M Szabat
- Diabetes Research Group, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 5358-2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Y Tang
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Key Lab of Hormones and Development, Ministry of Health, Metabolic Diseases Hospital, Tianjin Medical University, Tianjin 300070, China
| | - J Wang
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Department of Emergency, Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361004, China
| | - S Salö
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - L Eliasson
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - I Artner
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - M Fex
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - J D Johnson
- Diabetes Research Group, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 5358-2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - C B Wollheim
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Department of Cell Physiology and Metabolism, University Medical Center, Rue Michel-Servet 1, 1206 Geneva, Switzerland
| | - J M J Derry
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA
| | - B Mecham
- Trialomics, 6310 12th Avenue NE, Seattle, Washington 98115, USA
| | - P Spégel
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Centre for Analysis and Synthesis, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden
| | - H Mulder
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - I G Costa
- Institute of Biomedical Engineering, RWTH Aachen University Hospital, Pauwelstr 19, 52074 Aachen, Germany
| | - E Zhang
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - A H Rosengren
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA.,Department of Neuroscience and Physiology, University of Gothenburg, Box 100, SE-405 30 Gothenburg, Sweden
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Restoration of Lepr in β cells of Lepr null mice does not prevent hyperinsulinemia and hyperglycemia. Mol Metab 2017; 6:585-593. [PMID: 28580288 PMCID: PMC5444109 DOI: 10.1016/j.molmet.2017.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 04/02/2017] [Accepted: 04/04/2017] [Indexed: 11/22/2022] Open
Abstract
Objective The adipose-derived hormone leptin plays an important role in regulating body weight and glucose homeostasis. Leptin receptors are expressed in the central nervous system as well as peripheral tissues involved in regulating glucose homeostasis, including insulin-producing β cells of the pancreas. Previous studies assessing the role of leptin receptors in β cells used Cre-loxP to disrupt the leptin receptor gene (Lepr) in β cells, but variable results were obtained. Furthermore, recombination of Lepr was observed in the hypothalamus or exocrine pancreas, in addition to the β cells, and Lepr in non-β cells may have compensated for the loss of Lepr in β cells, thus making it difficult to assess the direct effects of Lepr in β cells. To determine the significance of Lepr exclusively in β cells, we chose to selectively restore Lepr in β cells of Lepr null mice (LeprloxTB/loxTB). Materials and methods We used a mouse model in which endogenous expression of Lepr was disrupted by a loxP-flanked transcription blocker (LeprloxTB/loxTB), but was restored by Cre recombinase knocked into the Ins1 gene, which is specifically expressed in β cells (Ins1Cre). We bred LeprloxTB/loxTB and Ins1Cre mice to generate LeprloxTB/loxTB and LeprloxTB/loxTBIns1Cre mice, as well as Leprwt/wt and Leprwt/wtIns1Cre littermate mice. Male and female mice were weighed weekly between 6 and 11 weeks of age and fasting blood glucose was measured during this time. Oral glucose was administered to mice aged 7–12 weeks to assess glucose tolerance and insulin secretion. Relative β and α cell area and islet size were also assessed by immunostaining and analysis of pancreas sections of 12–14 week old mice. Results Male and female LeprloxTB/loxTB mice, lacking whole-body expression of Lepr, had a phenotype similar to db/db mice characterized by obesity, hyperinsulinemia, glucose intolerance, and impaired glucose stimulated insulin secretion. Despite restoring Lepr in β cells of LeprloxTB/loxTB mice, fasting insulin levels, blood glucose levels and body weight were comparable between LeprloxTB/loxTBIns1Cre mice and LeprloxTB/loxTB littermates. Furthermore, glucose tolerance and insulin secretion in male and female LeprloxTB/loxTBIns1Cre mice were similar to that observed in LeprloxTB/loxTB mice. Analysis of pancreatic insulin positive area revealed that restoration of Lepr in β cells of LeprloxTB/loxTB mice did not prevent hyperplasia of insulin positive cells nor did it rescue Glut-2 expression. Conclusion Collectively, these data suggest that direct action of leptin on β cells is insufficient to restore normal insulin secretion and glucose tolerance in mice without leptin receptor signaling elsewhere. Restoration of Lepr in β cells of Lepr null mice does not prevent hyperinsulinemia. Leptin receptors in β cells do not inhibit islet hyperplasia. Hyperglycemia and glucose intolerance persist despite restoration of Lepr in β cells of Lepr null mice.
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Hogan MF, Liu AW, Peters MJ, Willard JR, Rabbani Z, Bartholomew EC, Ottley A, Hull RL. Markers of Islet Endothelial Dysfunction Occur in Male B6.BKS(D)-Leprdb/J Mice and May Contribute to Reduced Insulin Release. Endocrinology 2017; 158:293-303. [PMID: 27870582 PMCID: PMC5413084 DOI: 10.1210/en.2016-1393] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 11/18/2016] [Indexed: 11/19/2022]
Abstract
Islet endothelial cells produce paracrine factors that support β-cell function and growth. Endothelial dysfunction underlies diabetic microvascular complications; thus, we hypothesized that in diabetes, islet endothelial cells become dysfunctional, which may contribute to β-cell secretory dysfunction. Islets/islet endothelial cells were isolated from diabetic B6.BKS(D)-Leprdb/J male (db/db) mice, treated with or without the glucose-lowering agent phlorizin, or from C57BL/6J mice fed a high-fat diet for 18 weeks and appropriate controls. Messenger RNA (mRNA) and/or the protein levels of the cell adhesion molecule E-selectin (Sele), proinflammatory cytokine interleukin-6 (Il6), vasoconstrictor endothelin-1 (Edn1), and endothelial nitric oxide synthase (Nos3; Nos3) were evaluated, along with advanced glycation end product immunoreactivity. Furthermore, an islet endothelial cell line (MS-1) was exposed to diabetic factors (glucose, palmitate, insulin, and tumor necrosis factor-α) for six days. Conditioned media were collected from these cells, incubated with isolated islets, and glucose-stimulated insulin secretion and insulin content were assessed. Islet endothelial cells from db/db mice exhibited increased Sele, Il6, and Edn1 mRNA levels, decreased Nos3 protein, and accumulation of advanced glycation end products. Phlorizin treatment significantly increased Nos3 protein levels but did not alter expression of the other markers. High-fat feeding in C57BL/6J mice resulted in increased islet Sele, Il6, and Edn1 but no change in Nos3. Exposure of islets to conditioned media from MS-1 cells cultured in diabetic conditions resulted in a 50% decrease in glucose-stimulated insulin secretion and 30% decrease in insulin content. These findings demonstrate that, in diabetes, islet endothelial cells show evidence of a dysfunctional phenotype, which may contribute to loss of β-cell function.
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Affiliation(s)
- Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
- Department of Medicine, University of Washington, Seattle, Washington
| | - Amy W Liu
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
- Department of Medicine, University of Washington, Seattle, Washington
| | - Michael J Peters
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
| | - Joshua R Willard
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
| | - Zaheen Rabbani
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
- Department of Medicine, University of Washington, Seattle, Washington
| | | | - Adam Ottley
- Department of Medicine, University of Washington, Seattle, Washington
| | - Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
- Department of Medicine, University of Washington, Seattle, Washington
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Brereton MF, Rohm M, Ashcroft FM. β-Cell dysfunction in diabetes: a crisis of identity? Diabetes Obes Metab 2016; 18 Suppl 1:102-9. [PMID: 27615138 PMCID: PMC5890905 DOI: 10.1111/dom.12732] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 04/25/2016] [Indexed: 12/23/2022]
Abstract
Type 2 diabetes is characterized by insulin resistance and a progressive loss of β-cell function induced by a combination of both β-cell loss and impaired insulin secretion from remaining β-cells. Here, we review the fate of the β-cell under chronic hyperglycaemic conditions with regard to β-cell mass, gene expression, hormone content, secretory capacity and the ability to de- or transdifferentiate into other cell types. We compare data from various in vivo and in vitro models of diabetes with a novel mouse model of inducible, reversible hyperglycaemia (βV59M mice). We suggest that insulin staining using standard histological methods may not always provide an accurate estimation of β-cell mass or number. We consider how β-cell identity is best defined, and whether expression of transcription factors normally found in islet progenitor cells, or in α-cells, implies that mature β-cells have undergone dedifferentiation or transdifferentiation. We propose that even in long-standing diabetes, β-cells predominantly remain β-cells-but not as we know them.
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Affiliation(s)
- M F Brereton
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, UK
| | - M Rohm
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, UK
| | - F M Ashcroft
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, UK.
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The MDM2-p53-pyruvate carboxylase signalling axis couples mitochondrial metabolism to glucose-stimulated insulin secretion in pancreatic β-cells. Nat Commun 2016; 7:11740. [PMID: 27265727 PMCID: PMC4897763 DOI: 10.1038/ncomms11740] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 04/26/2016] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial metabolism is pivotal for glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells. However, little is known about the molecular machinery that controls the homeostasis of intermediary metabolites in mitochondria. Here we show that the activation of p53 in β-cells, by genetic deletion or pharmacological inhibition of its negative regulator MDM2, impairs GSIS, leading to glucose intolerance in mice. Mechanistically, p53 activation represses the expression of the mitochondrial enzyme pyruvate carboxylase (PC), resulting in diminished production of the TCA cycle intermediates oxaloacetate and NADPH, and impaired oxygen consumption. The defective GSIS and mitochondrial metabolism in MDM2-null islets can be rescued by restoring PC expression. Under diabetogenic conditions, MDM2 and p53 are upregulated, whereas PC is reduced in mouse β-cells. Pharmacological inhibition of p53 alleviates defective GSIS in diabetic islets by restoring PC expression. Thus, the MDM2-p53-PC signalling axis links mitochondrial metabolism to insulin secretion and glucose homeostasis, and could represent a therapeutic target in diabetes.
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Do OH, Gunton JE, Gaisano HY, Thorn P. Changes in beta cell function occur in prediabetes and early disease in the Lepr (db) mouse model of diabetes. Diabetologia 2016; 59:1222-30. [PMID: 27048248 PMCID: PMC4869737 DOI: 10.1007/s00125-016-3942-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 02/29/2016] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Type 2 diabetes is a progressive disease that increases morbidity and the risk of premature death. Glucose dysregulation, such as elevated fasting blood glucose, is observed prior to diabetes onset. A decline in beta cell insulin secretion contributes to the later stages of diabetes, but it is not known what, if any, functional beta cell changes occur in prediabetes and early disease. METHODS The Lepr (db) mouse (age 13-18 weeks) was used as a model of type 2 diabetes and a two-photon granule fusion assay was used to characterise the secretory response of pancreatic beta cells. RESULTS We identified a prediabetic state in db/db mice where the animals responded normally to a glucose challenge but have elevated fasting blood glucose. Isolated islets from prediabetic animals secreted more and were bigger. Insulin secretion, normalised to insulin content, was similar to wild type but basal insulin secretion was elevated. There was increased glucose-induced granule fusion with a high prevalence of granule-granule fusion. The glucose-induced calcium response was not changed but there was altered expression of the exocytic machinery. db/db animals at the next stage of disease had overt glucose intolerance. Isolated islets from these animals had reduced insulin secretion, reduced glucose-induced granule fusion events and decreased calcium responses to glucose. CONCLUSIONS/INTERPRETATION Beta cell function is altered in prediabetes and there are further changes in the progression to early disease.
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Affiliation(s)
- Oanh H Do
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, Sydney, NSW, 2050, Australia
| | - Jenny E Gunton
- Westmead Hospital, Sydney, NSW, 2145, Australia
- Westmead Institute for Medical Research, PO Box 412, Westmead, Sydney, NSW, 2145, Australia
| | - Herbert Y Gaisano
- School of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Peter Thorn
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia.
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, Sydney, NSW, 2050, Australia.
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45
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Life and death of β cells in Type 1 diabetes: A comprehensive review. J Autoimmun 2016; 71:51-8. [PMID: 27017348 DOI: 10.1016/j.jaut.2016.02.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 01/31/2016] [Accepted: 02/01/2016] [Indexed: 01/03/2023]
Abstract
Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic β cells. Immune modulators have achieved some success in modifying the course of disease progression in T1D. However, there are parallel declines in C-peptide levels in treated and control groups after initial responses. In this review, we discuss mechanisms of β cell death in T1D that involve necrosis and apoptosis. New technologies are being developed to enable visualization of insulitis and β cell mass involving positron emission transmission that identifies β cell ligands and magnetic resonance imaging that can identify vascular leakage. Molecular signatures that identify β cell derived insulin DNA that is released from dying cells have been described and applied to clinical settings. We also consider changes in β cells that occur during disease progression including the induction of DNA methyltransferases that may affect the function and differentiation of β cells. Our findings from newer data suggest that the model of chronic long standing β cell killing should be reconsidered. These studies indicate that the pathophysiology is accelerated in the peridiagnosis period and manifest by increased rates of β cell killing and insulin secretory impairments over a shorter period than previously thought. Finally, we consider cellular explanations to account for the ongoing loss of insulin production despite continued immune therapy that may identify potential targets for treatment. The progressive decline in β cell function raises the question as to whether β cell failure that is independent of immune attack may be involved.
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Wang LH, Baker NE. E Proteins and ID Proteins: Helix-Loop-Helix Partners in Development and Disease. Dev Cell 2016; 35:269-80. [PMID: 26555048 DOI: 10.1016/j.devcel.2015.10.019] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/18/2015] [Accepted: 10/23/2015] [Indexed: 01/12/2023]
Abstract
The basic Helix-Loop-Helix (bHLH) proteins represent a well-known class of transcriptional regulators. Many bHLH proteins act as heterodimers with members of a class of ubiquitous partners, the E proteins. A widely expressed class of inhibitory heterodimer partners-the Inhibitor of DNA-binding (ID) proteins-also exists. Genetic and molecular analyses in humans and in knockout mice implicate E proteins and ID proteins in a wide variety of diseases, belying the notion that they are non-specific partner proteins. Here, we explore relationships of E proteins and ID proteins to a variety of disease processes and highlight gaps in knowledge of disease mechanisms.
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Affiliation(s)
- Lan-Hsin Wang
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Nicholas E Baker
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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Sheng C, Li F, Lin Z, Zhang M, Yang P, Bu L, Sheng H, Li H, Qu S. Reversibility of β-Cell-Specific Transcript Factors Expression by Long-Term Caloric Restriction in db/db Mouse. J Diabetes Res 2016; 2016:6035046. [PMID: 26998492 PMCID: PMC4779534 DOI: 10.1155/2016/6035046] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 12/09/2015] [Accepted: 12/14/2015] [Indexed: 12/31/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by β-cell dedifferentiation, but underlying mechanisms remain unclear. The purpose of the current study was to explore the mechanisms of β-cell dedifferentiation with and without long-term control of calorie intake. We used a diabetes mouse model (db/db) to analyze the changes in the expression levels of β-cell-specific transcription factors (TFs) and functional factors with long-term caloric restriction (CR). Our results showed that chronic euglycemia was maintained in the db/db mice with long-term CR intervention, and β-cell dedifferentiation was significantly reduced. The expression of Glut2, Pdx1, and Nkx6.1 was reversed, while MafA expression was significantly increased with long-term CR. GLP-1 pathway was reactivated with long-term CR. Our work showed that the course of β-cell dedifferentiation can intervene by long-term control of calorie intake. Key β-cell-specific TFs and functional factors play important roles in maintaining β-cell differentiation. Targeting these factors could optimize T2D therapies.
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Affiliation(s)
- Chunjun Sheng
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Feng Li
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
- *Feng Li: and
| | - Ziwei Lin
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Manna Zhang
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Peng Yang
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Le Bu
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Hui Sheng
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Hong Li
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Shen Qu
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
- *Shen Qu:
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Grgurevic L, Christensen GL, Schulz TJ, Vukicevic S. Bone morphogenetic proteins in inflammation, glucose homeostasis and adipose tissue energy metabolism. Cytokine Growth Factor Rev 2015; 27:105-18. [PMID: 26762842 DOI: 10.1016/j.cytogfr.2015.12.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 12/10/2015] [Accepted: 12/23/2015] [Indexed: 12/13/2022]
Abstract
Bore morphogenetic proteins (BMPs) are members of the transforming growth factor (TGF)-β superfamily, a group of secreted proteins that regulate embryonic development. This review summarizes the effects of BMPs on physiological processes not exclusively linked to the musculoskeletal system. Specifically, we focus on the involvement of BMPs in inflammatory disorders, e.g. fibrosis, inflammatory bowel disease, anchylosing spondylitis, rheumatoid arthritis. Moreover, we discuss the role of BMPs in the context of vascular disorders, and explore the role of these signalling proteins in iron homeostasis (anaemia, hemochromatosis) and oxidative damage. The second and third parts of this review focus on BMPs in the development of metabolic pathologies such as type-2 diabetes mellitus and obesity. The pancreatic beta cells are the sole source of the hormone insulin and BMPs have recently been implicated in pancreas development as well as control of adult glucose homeostasis. Lastly, we review the recently recognized role of BMPs in brown adipose tissue formation and their consequences for energy expenditure and adiposity. In summary, BMPs play a pivotal role in metabolism beyond their role in skeletal homeostasis. However, increased understanding of these pleiotropic functions also highlights the necessity of tissue-specific strategies when harnessing BMP action as a therapeutic target.
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Affiliation(s)
- Lovorka Grgurevic
- University of Zagreb School of Medicine, Center for Translational and Clinical Research, Laboratory for Mineralized Tissues, Zagreb, Croatia
| | | | - Tim J Schulz
- German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany; German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
| | - Slobodan Vukicevic
- University of Zagreb School of Medicine, Center for Translational and Clinical Research, Laboratory for Mineralized Tissues, Zagreb, Croatia.
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Hoang Do O, Thorn P. Insulin secretion from beta cells within intact islets: location matters. Clin Exp Pharmacol Physiol 2015; 42:406-14. [PMID: 25676261 PMCID: PMC4418378 DOI: 10.1111/1440-1681.12368] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 12/21/2014] [Accepted: 01/06/2015] [Indexed: 12/17/2022]
Abstract
The control of hormone secretion is central to body homeostasis, and its dysfunction is important in many diseases. The key cellular steps that lead to hormone secretion have been identified, and the stimulus-secretion pathway is understood in outline for many endocrine cells. In the case of insulin secretion from pancreatic beta cells, this pathway involves the uptake of glucose, cell depolarization, calcium entry, and the triggering of the fusion of insulin-containing granules with the cell membrane. The wealth of information on the control of insulin secretion has largely been obtained from isolated single-cell studies. However, physiologically, beta cells exist within the islets of Langerhans, with structural and functional specializations that are not preserved in single-cell cultures. This review focuses on recent work that is revealing distinct aspects of insulin secretion from beta cells within the islet.
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Affiliation(s)
- Oanh Hoang Do
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Qld, Australia
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Shimo N, Matsuoka TA, Miyatsuka T, Takebe S, Tochino Y, Takahara M, Kaneto H, Shimomura I. Short-term selective alleviation of glucotoxicity and lipotoxicity ameliorates the suppressed expression of key β-cell factors under diabetic conditions. Biochem Biophys Res Commun 2015; 467:948-54. [DOI: 10.1016/j.bbrc.2015.10.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 10/07/2015] [Indexed: 01/14/2023]
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