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Fagundes RR, Zaldumbide A, Taylor CT. Role of hypoxia-inducible factor 1 in type 1 diabetes. Trends Pharmacol Sci 2024:S0165-6147(24)00143-3. [PMID: 39127527 DOI: 10.1016/j.tips.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 07/08/2024] [Accepted: 07/11/2024] [Indexed: 08/12/2024]
Abstract
Type 1 diabetes (T1D) is a common autoimmune disease in which dysregulated glucose metabolism is a key feature. T1D is both poorly understood and in need of improved therapeutics. Hypoxia is frequently encountered in multiple tissues in T1D patients including the pancreas and sites of diabetic complications. Hypoxia-inducible factor (HIF)-1, a ubiquitous master regulator of the adaptive response to hypoxia, promotes glucose metabolism through transcriptional and non-transcriptional mechanisms and alters disease progression in multiple preclinical T1D models. However, how HIF-1 activation in β-cells of the pancreas and immune cells (two key cell types in T1D) ultimately affects disease progression remains controversial. We discuss recent advances in our understanding of the role of hypoxia/HIF-1-induced glycolysis in T1D and explore the possible use of drugs targeting this pathway as potential new therapeutics.
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Affiliation(s)
- Raphael R Fagundes
- Department of Cell and Chemical Biology, Leiden University Medical Center, Albinusdreef 2, Leiden, The Netherlands
| | - Arnaud Zaldumbide
- Department of Cell and Chemical Biology, Leiden University Medical Center, Albinusdreef 2, Leiden, The Netherlands
| | - Cormac T Taylor
- School of Medicine and Conway Institute of Biomolecular and Biomedical Research and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland.
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2
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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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3
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Cao S, Wang L, Feng Y, Peng XD, Li LM. A data integration approach unveils a transcriptional signature of type 2 diabetes progression in rat and human islets. PLoS One 2023; 18:e0292579. [PMID: 37816033 PMCID: PMC10564241 DOI: 10.1371/journal.pone.0292579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 09/22/2023] [Indexed: 10/12/2023] Open
Abstract
Pancreatic islet failure is a key characteristic of type 2 diabetes besides insulin resistance. To get molecular insights into the pathology of islets in type 2 diabetes, we developed a computational approach to integrating expression profiles of Goto-Kakizaki and Wistar rat islets from a designed experiment with those of the human islets from an observational study. A principal gene-eigenvector in the expression profiles characterized by up-regulated angiogenesis and down-regulated oxidative phosphorylation was identified conserved across the two species. In the case of Goto-Kakizaki versus Wistar islets, such alteration in gene expression can be verified directly by the treatment-control tests over time, and corresponds to the alteration of α/β-cell distribution obtained by quantifying the islet micrographs. Furthermore, the correspondence between the dual sample- and gene-eigenvectors unveils more delicate structures. In the case of rats, the up- and down-trend of insulin mRNA levels before and after week 8 correspond respectively to the top two principal eigenvectors. In the case of human, the top two principal eigenvectors correspond respectively to the late and early stages of diabetes. According to the aggregated expression signature, a large portion of genes involved in the hypoxia-inducible factor signaling pathway, which activates transcription of angiogenesis, were significantly up-regulated. Furthermore, top-ranked anti-angiogenic genes THBS1 and PEDF indicate the existence of a counteractive mechanism that is in line with thickened and fragmented capillaries found in the deteriorated islets. Overall, the integrative analysis unravels the principal transcriptional alterations underlying the islet deterioration of morphology and insulin secretion along type 2 diabetes progression.
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Affiliation(s)
- Shenghao Cao
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Linting Wang
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Yance Feng
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Xiao-ding Peng
- Department of Biochemistry and Molecular Genetics, The University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Lei M. Li
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
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Liu J, Liu S, Yu Z, Qiu X, Jiang R, Li W. Uncovering the gene regulatory network of type 2 diabetes through multi-omic data integration. J Transl Med 2022; 20:604. [PMID: 36527108 PMCID: PMC9756634 DOI: 10.1186/s12967-022-03826-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Type 2 diabetes (T2D) onset is a complex, organized biological process with multilevel regulation, and its physiopathological mechanisms are yet to be elucidated. This study aims to find out the key drivers and pathways involved in the pathogenesis of T2D through multi-omics analysis. METHODS The datasets used in the experiments comprise three groups: (1) genomic (2) transcriptomic, and (3) epigenomic categories. Then, a series of bioinformatics technologies including Marker set enrichment analysis (MSEA), weighted key driver analysis (wKDA) was performed to identify key drivers. The hub genes were further verified by the Receiver Operator Characteristic (ROC) Curve analysis, proteomic analysis, and Real-time quantitative polymerase chain reaction (RT-qPCR). The multi-omics network was applied to the Pharmomics pipeline in Mergeomics to identify drug candidates for T2D treatment. Then, we used the drug-gene interaction network to conduct network pharmacological analysis. Besides, molecular docking was performed using AutoDock/Vina, a computational docking program. RESULTS Module-gene interaction network was constructed using MSEA, which revealed a significant enrichment of immune-related activities and glucose metabolism. Top 10 key drivers (PSMB9, COL1A1, COL4A1, HLA-DQB1, COL3A1, IRF7, COL5A1, CD74, HLA-DQA1, and HLA-DRB1) were selected by wKDA analysis. Among these, COL5A1, IRF7, CD74, and HLA-DRB1 were verified to have the capability to diagnose T2D, and expression levels of PSMB9 and CD74 had significantly higher in T2D patients. We further predict the co-expression network and transcription factor (TF) binding specificity of the key driver. Besides, based on module interaction networks and key driver networks, 17 compounds are considered to possess T2D-control potential, such as sunitinib. CONCLUSIONS We identified signature genes, biomolecular processes, and pathways using multi-omics networks. Moreover, our computational network analysis revealed potential novel strategies for pharmacologic interventions of T2D.
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Affiliation(s)
- Jiachen Liu
- Department of General Surgery, Third Xiangya Hospital Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China
- Xiangya Medical College, Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China
- The Center of Systems Biology and Data science, School of Basic Medical Science, Central South University, Changsha, Hunan, People's Republic of China
| | - Shenghua Liu
- Department of General Surgery, Third Xiangya Hospital Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China
- Xiangya Medical College, Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China
| | - Zhaomei Yu
- Department of Thyroid and Breast Surgery, The Frist Afflicted Hospital of Fujian Medical University, No. 20 Chayzhong Road, Taijiang District, Fuzhou, 350005, Fujian, People's Republic of China
| | - Xiaorui Qiu
- Xiangya Medical College, Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China
| | - Rundong Jiang
- Department of General Surgery, Third Xiangya Hospital Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China
| | - Weizheng Li
- Department of General Surgery, Third Xiangya Hospital Central South University, No. 138 Tongzipo Road Yuelu District, Changsha, 410013, Hunan, People's Republic of China.
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RNA binding protein HuD mediates the crosstalk between β cells and islet endothelial cells by the regulation of Endostatin and Serpin E1 expression. Cell Death Dis 2022; 13:1019. [PMID: 36470872 PMCID: PMC9722926 DOI: 10.1038/s41419-022-05465-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022]
Abstract
RNA binding protein HuD plays essential roles in gene expression by regulating RNA metabolism, and its dysregulation is involved in the pathogenesis of several diseases, including tumors, neurodegenerative diseases, and diabetes. Here, we explored HuD-mediated differential expression of secretory proteins in mouse insulinoma βTC6 cells using a cytokine array. Endostatin and Serpin E1 that play anti-angiogenic roles were identified as differentially expressed proteins by HuD. HuD knockdown increased the expression of α chain of collagen XVIII (Col18a1), a precursor form of endostatin, and Serpin E1 by associating with the 3'-untranslated regions (UTRs) of Col18a1 and Serpin E1 mRNAs. Reporter analysis revealed that HuD knockdown increased the translation of EGFP reporters containing 3'UTRs of Col18a1 and Serpin E1 mRNAs, which suggests the role of HuD as a translational repressor. Co-cultures of βTC6 cells and pancreatic islet endothelial MS1 cells were used to assess the crosstalk between β cells and islet endothelial cells, and the results showed that HuD downregulation in βTC6 cells inhibited the growth and migration of MS1 cells. Ectopic expression of HuD decreased Col18a1 and Serpin E1 expression, while increasing the markers of islet vascular cells in the pancreas of db/db mice. Taken together, these results suggest that HuD has the potential to regulate the crosstalk between β cells and islet endothelial cells by regulating Endostatin and Serpin E1 expression, thereby contributing to the maintenance of homeostasis in the islet microenvironment.
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Chen K, Zhang J, Huang Y, Tian X, Yang Y, Dong A. Single-cell RNA-seq transcriptomic landscape of human and mouse islets and pathological alterations of diabetes. iScience 2022; 25:105366. [PMID: 36339258 PMCID: PMC9626680 DOI: 10.1016/j.isci.2022.105366] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/13/2022] [Accepted: 10/12/2022] [Indexed: 11/15/2022] Open
Abstract
Single-cell RNA sequencing has paved the way for delineating the pancreatic islet cell atlas and identifying hallmarks of diabetes. However, pathological alterations of type 2 diabetes (T2D) remain unclear. We isolated pancreatic islets from control and T2D mice for single-cell RNA sequencing (scRNA-seq) and retrieved multiple datasets from the open databases. The complete islet cell landscape and robust marker genes and transcription factors of each endocrine cell type were identified. GLRA1 was restricted to beta cells, and beta cells exhibited obvious heterogeneity. The beta subcluster in the T2D mice remarkably decreased the expression of Slc2a2, G6pc2, Mafa, Nkx6-1, Pdx1, and Ucn3 and had higher unfolded protein response (UPR) scores than in the control mice. Moreover, we developed a Web-based interactive tool, creating new opportunities for the data mining of pancreatic islet scRNA-seq datasets. In conclusion, our work provides a valuable resource for a deeper understanding of the pathological mechanism underlying diabetes. Cross-species scRNA-seq reveals the complete cell landscape of the islets of Langerhans We identify the robust marker genes and TFs of each endocrine and exocrine cell type Pathological alterations of beta cells in type 2 diabetes are explored A Web-based interactive tool is established for pancreatic islet scRNA-seq datasets
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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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Liang R, Liu N, Cao J, Liu T, Sun P, Cai X, Zhang L, Liu Y, Zou J, Wang L, Ding X, Zhang B, Shen Z, Yoshida S, Dou J, Wang S. HIF-1α/FOXO1 axis regulated autophagy is protective for β cell survival under hypoxia in human islets. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166356. [PMID: 35124169 DOI: 10.1016/j.bbadis.2022.166356] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 01/18/2023]
Abstract
β cells suffer from hypoxia due to the rapid metabolic rate to supply insulin production. Mechanistic study of β cell survival under hypoxia may shed light on the β cell mass loss in type 2 diabetes mellitus (T2DM). Here, we found that the expressions of LC3 and p62/SQSTM1, two key autophagy regulators, were significantly higher in β cells than that in non-β endocrine cells in both non-diabetic and T2DM pancreases, and the autophagy process was accelerated upon Cobalt Chloride (CoCl2) treatment in ex vivo cultured primary human islets. Meanwhile, CoCl2 induced the upregulation of FOXO1 in human islets, where HIF-1α played a key role. CoCl2 treatment caused the increase of β cell apoptosis, yet inhibiting autophagy by Chloroquine or by FOXO1 knockdown further aggravated apoptosis, suggesting that FOXO1-regulated autophagy is protective for β cell survival under hypoxia. Immunofluorescence staining showed that LC3 and p62/SQSTM1 expressions were significantly decreased in T2DM patients and negatively correlated with HbA1c, indicating that the autophagy capacity of β cells is impaired along with the progression of the disease. Our study revealed that HIF-1α/FOXO1 regulated autophagy benefits β cell survival under hypoxia and autophagy dysregulation may account for β cell mass loss in T2DM. BRIEF SUMMARY: Our study revealed that HIF-1α/FOXO1 regulated autophagy benefits β cell survival under hypoxia and autophagy dysregulation may account for β cell mass loss in T2DM.
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Affiliation(s)
- Rui Liang
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Na Liu
- NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China; Tianjin Key Laboratory for Organ Transplantation, Tianjin First Central Hospital, Tianjin 300192, PR China
| | - Jinglin Cao
- Department of Hepatobiliary Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang 050051, PR China
| | - Tengli Liu
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Peng Sun
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Xiangheng Cai
- School of Medicine, Nankai University, Tianjin 300071, PR China
| | - Lanqiu Zhang
- Tianjin Key Laboratory of Acute Abdomen Disease Associated Organ Injury and ITCWM Repair, Institute of Acute Abdominal Diseases, Tianjin Nankai Hospital, Tianjin, 300100, PR China
| | - Yaojuan Liu
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Jiaqi Zou
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Le Wang
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Xuejie Ding
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Boya Zhang
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China
| | - Zhongyang Shen
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China; Tianjin Key Laboratory for Organ Transplantation, Tianjin First Central Hospital, Tianjin 300192, PR China
| | - Sei Yoshida
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300071, PR China.
| | - Jian Dou
- Department of Hepatobiliary Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang 050051, PR China.
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China; NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, PR China; Tianjin Key Laboratory for Organ Transplantation, Tianjin First Central Hospital, Tianjin 300192, PR China; School of Medicine, Nankai University, Tianjin 300071, PR China.
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10
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Sanchez PKM, Khazaei M, Gatineau E, Geravandi S, Lupse B, Liu H, Dringen R, Wojtusciszyn A, Gilon P, Maedler K, Ardestani A. LDHA is enriched in human islet alpha cells and upregulated in type 2 diabetes. Biochem Biophys Res Commun 2021; 568:158-166. [PMID: 34217973 DOI: 10.1016/j.bbrc.2021.06.065] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 06/20/2021] [Indexed: 12/25/2022]
Abstract
The lactate dehydrogenase isoform A (LDHA) is a key metabolic enzyme that preferentially catalyzes the conversion of pyruvate to lactate. Whereas LDHA is highly expressed in many tissues, its expression is turned off in the differentiated adult β-cell within the pancreatic islets. The repression of LDHA under normal physiological condition and its inappropriate upregulation under a diabetogenic environment is well-documented in rodent islets/β-cells but little is known about LDHA expression in human islet cells and whether its abundance is altered under diabetic conditions. Analysis of public single-cell RNA-seq (sc-RNA seq) data as well as cell type-specific immunolabeling of human pancreatic islets showed that LDHA was mainly localized in human α-cells while it is expressed at a very low level in β-cells. Furthermore, LDHA, both at mRNA and protein, as well as lactate production is upregulated in human pancreatic islets exposed to chronic high glucose treatment. Microscopic analysis of stressed human islets and autopsy pancreases from individuals with type 2 diabetes (T2D) showed LDHA upregulation mainly in human α-cells. Pharmacological inhibition of LDHA in isolated human islets enhanced insulin secretion under physiological conditions but did not significantly correct the deregulated secretion of insulin or glucagon under diabetic conditions.
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Affiliation(s)
| | - Mona Khazaei
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Eva Gatineau
- Pole of Endocrinology, Diabetes, and Nutrition (EDIN), Institute of Experimental and Clinical Research (IREC), Université Catholique de Louvain (UCLouvain), 1200, Brussels, Belgium
| | - Shirin Geravandi
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Blaz Lupse
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Huan Liu
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Ralf Dringen
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Anne Wojtusciszyn
- Department of Endocrinology, Diabetology and Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Patrick Gilon
- Pole of Endocrinology, Diabetes, and Nutrition (EDIN), Institute of Experimental and Clinical Research (IREC), Université Catholique de Louvain (UCLouvain), 1200, Brussels, Belgium
| | - Kathrin Maedler
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany.
| | - Amin Ardestani
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany; Department of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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11
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Tsai PS, Chiu CY, Sheu ML, Yang CY, Lan KC, Liu SH. Advanced glycation end products activated endothelial-to-mesenchymal transition in pancreatic islet endothelial cells and triggered islet fibrosis in diabetic mice. Chem Biol Interact 2021; 345:109562. [PMID: 34153226 DOI: 10.1016/j.cbi.2021.109562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/07/2021] [Accepted: 06/15/2021] [Indexed: 12/26/2022]
Abstract
Advanced glycation end products (AGEs) are associated with the pathogenesis of diabetic vascular complications. Induction of the endothelial-to-mesenchymal transition (EndMT) is associated with the pathogenesis of fibrotic diseases. The roles of AGEs in islet EndMT induction and diabetes-related islet microvasculopathy and fibrosis remain unclear. This study investigated the pathological roles of AGEs in islet EndMT induction and fibrosis in vitro and in vivo. Non-cytotoxic concentrations of AGEs upregulated the protein expression of fibronectin, vimentin, and α-smooth muscle actin (α-SMA) (mesenchymal/myofibroblast markers) and downregulated the protein expression of vascular endothelial (VE)-cadherin and cluster of differentiation (CD) 31 (endothelial cell markers) in cultured mouse pancreatic islet endothelial cells, which was prevented by the AGE cross-link breaker alagebrium chloride. In streptozotocin-induced diabetic mice, the average islet area and islet immunoreactivities for insulin and CD31 were decreased and the islet immunoreactivities for AGEs and α-SMA and fibrosis were increased, which were prevented by the AGE inhibitor aminoguanidine. Immunofluorescence double staining showed that α-SMA-positive staining co-localized with CD31-positive staining in the diabetic islets, which was effectively prevented by aminoguanidine. These results demonstrate that AGEs can induce EndMT in islet endothelial cells and islet fibrosis in diabetic mice, suggesting that AGE-induced EndMT may contribute to islet fibrosis in diabetes.
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Affiliation(s)
- Pei-Shan Tsai
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chen-Yuan Chiu
- Center of Consultation, Center for Drug Evaluation, Taipei, Taiwan
| | - Meei-Ling Sheu
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Ching-Yao Yang
- Department of Surgery, College of Medicine and National Taiwan University Hospital, National Taiwan University, Taipei, Taiwan
| | - Kuo-Cheng Lan
- Department of Emergency Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan; Department of Pediatrics, College of Medicine and Hospital, National Taiwan University, Taipei, Taiwan.
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12
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Roberts DD, Isenberg JS. CD47 and thrombospondin-1 regulation of mitochondria, metabolism, and diabetes. Am J Physiol Cell Physiol 2021; 321:C201-C213. [PMID: 34106789 DOI: 10.1152/ajpcell.00175.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Thrombospondin-1 (TSP1) is the prototypical member of a family of secreted proteins that modulate cell behavior by engaging with molecules in the extracellular matrix and with receptors on the cell surface. CD47 is widely displayed on many, if not all, cell types and is a high-affinity TSP1 receptor. CD47 is a marker of self that limits innate immune cell activities, a feature recently exploited to enhance cancer immunotherapy. Another major role for CD47 in health and disease is to mediate TSP1 signaling. TSP1 acting through CD47 contributes to mitochondrial, metabolic, and endocrine dysfunction. Studies in animal models found that elevated TSP1 expression, acting in part through CD47, causes mitochondrial and metabolic dysfunction. Clinical studies established that abnormal TSP1 expression positively correlates with obesity, fatty liver disease, and diabetes. The unabated increase in these conditions worldwide and the availability of CD47 targeting drugs justify a closer look into how TSP1 and CD47 disrupt metabolic balance and the potential for therapeutic intervention.
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Affiliation(s)
- David D Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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13
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Zhang AM, Wellberg EA, Kopp JL, Johnson JD. Hyperinsulinemia in Obesity, Inflammation, and Cancer. Diabetes Metab J 2021; 45:285-311. [PMID: 33775061 PMCID: PMC8164941 DOI: 10.4093/dmj.2020.0250] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/23/2020] [Indexed: 12/13/2022] Open
Abstract
The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.
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Affiliation(s)
- Anni M.Y. Zhang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth A. Wellberg
- Department of Pathology, University of Oklahoma Health Sciences Center, Stephenson Cancer Center, Harold Hamm Diabetes Center, Oklahoma City, OK, USA
| | - Janel L. Kopp
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - James D. Johnson
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
- Corresponding author: James D. Johnson https://orcid.org/0000-0002-7523-9433 Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2329 W Mall Vancouver, BC V6T 1Z4, Vancouver, BC, Canada E-mail:
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14
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Šrámek J, Němcová-Fürstová V, Kovář J. Molecular Mechanisms of Apoptosis Induction and Its Regulation by Fatty Acids in Pancreatic β-Cells. Int J Mol Sci 2021; 22:4285. [PMID: 33924206 PMCID: PMC8074590 DOI: 10.3390/ijms22084285] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/09/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β-cell failure and death contribute significantly to the pathogenesis of type 2 diabetes. One of the main factors responsible for β-cell dysfunction and subsequent cell death is chronic exposure to increased concentrations of FAs (fatty acids). The effect of FAs seems to depend particularly on the degree of their saturation. Saturated FAs induce apoptosis in pancreatic β-cells, whereas unsaturated FAs are well tolerated and are even capable of inhibiting the pro-apoptotic effect of saturated FAs. Molecular mechanisms of apoptosis induction by saturated FAs in β-cells are not completely elucidated. Saturated FAs induce ER stress, which in turn leads to activation of all ER stress pathways. When ER stress is severe or prolonged, apoptosis is induced. The main mediator seems to be the CHOP transcription factor. Via regulation of expression/activity of pro- and anti-apoptotic Bcl-2 family members, and potentially also through the increase in ROS production, CHOP switches on the mitochondrial pathway of apoptosis induction. ER stress signalling also possibly leads to autophagy signalling, which may activate caspase-8. Saturated FAs activate or inhibit various signalling pathways, i.e., p38 MAPK signalling, ERK signalling, ceramide signalling, Akt signalling and PKCδ signalling. This may lead to the activation of the mitochondrial pathway of apoptosis, as well. Particularly, the inhibition of the pro-survival Akt signalling seems to play an important role. This inhibition may be mediated by multiple pathways (e.g., ER stress signalling, PKCδ and ceramide) and could also consequence in autophagy signalling. Experimental evidence indicates the involvement of certain miRNAs in mechanisms of FA-induced β-cell apoptosis, as well. In the rather rare situations when unsaturated FAs are also shown to be pro-apoptotic, the mechanisms mediating this effect in β-cells seem to be the same as for saturated FAs. To conclude, FA-induced apoptosis rather appears to be preceded by complex cross talks of multiple signalling pathways. Some of these pathways may be regulated by decreased membrane fluidity due to saturated FA incorporation. Few data are available concerning molecular mechanisms mediating the protective effect of unsaturated FAs on the effect of saturated FAs. It seems that the main possible mechanism represents a rather inhibitory intervention into saturated FA-induced pro-apoptotic signalling than activation of some pro-survival signalling pathway(s) or metabolic interference in β-cells. This inhibitory intervention may be due to an increase of membrane fluidity.
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Affiliation(s)
- Jan Šrámek
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
| | - Vlasta Němcová-Fürstová
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
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15
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Benáková Š, Holendová B, Plecitá-Hlavatá L. Redox Homeostasis in Pancreatic β-Cells: From Development to Failure. Antioxidants (Basel) 2021; 10:antiox10040526. [PMID: 33801681 PMCID: PMC8065646 DOI: 10.3390/antiox10040526] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/16/2022] Open
Abstract
Redox status is a key determinant in the fate of β-cell. These cells are not primarily detoxifying and thus do not possess extensive antioxidant defense machinery. However, they show a wide range of redox regulating proteins, such as peroxiredoxins, thioredoxins or thioredoxin reductases, etc., being functionally compartmentalized within the cells. They keep fragile redox homeostasis and serve as messengers and amplifiers of redox signaling. β-cells require proper redox signaling already in cell ontogenesis during the development of mature β-cells from their progenitors. We bring details about redox-regulated signaling pathways and transcription factors being essential for proper differentiation and maturation of functional β-cells and their proliferation and insulin expression/maturation. We briefly highlight the targets of redox signaling in the insulin secretory pathway and focus more on possible targets of extracellular redox signaling through secreted thioredoxin1 and thioredoxin reductase1. Tuned redox homeostasis can switch upon chronic pathological insults towards the dysfunction of β-cells and to glucose intolerance. These are characteristics of type 2 diabetes, which is often linked to chronic nutritional overload being nowadays a pandemic feature of lifestyle. Overcharged β-cell metabolism causes pressure on proteostasis in the endoplasmic reticulum, mainly due to increased demand on insulin synthesis, which establishes unfolded protein response and insulin misfolding along with excessive hydrogen peroxide production. This together with redox dysbalance in cytoplasm and mitochondria due to enhanced nutritional pressure impact β-cell redox homeostasis and establish prooxidative metabolism. This can further affect β-cell communication in pancreatic islets through gap junctions. In parallel, peripheral tissues losing insulin sensitivity and overall impairment of glucose tolerance and gut microbiota establish local proinflammatory signaling and later systemic metainflammation, i.e., low chronic inflammation prooxidative properties, which target β-cells leading to their dedifferentiation, dysfunction and eventually cell death.
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Affiliation(s)
- Štěpánka Benáková
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- First Faculty of Medicine, Charles University, Katerinska 1660/32, 121 08 Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- Department of Mitochondrial Physiology, Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
- Correspondence: ; Tel.: +420-296-442-285
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16
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Xiong Y, Scerbo MJ, Seelig A, Volta F, O'Brien N, Dicker A, Padula D, Lickert H, Gerdes JM, Berggren PO. Islet vascularization is regulated by primary endothelial cilia via VEGF-A-dependent signaling. eLife 2020; 9:56914. [PMID: 33200981 PMCID: PMC7695455 DOI: 10.7554/elife.56914] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 11/16/2020] [Indexed: 12/31/2022] Open
Abstract
Islet vascularization is essential for intact islet function and glucose homeostasis. We have previously shown that primary cilia directly regulate insulin secretion. However, it remains unclear whether they are also implicated in islet vascularization. At eight weeks, murine Bbs4-/-islets show significantly lower intra-islet capillary density with enlarged diameters. Transplanted Bbs4-/- islets exhibit delayed re-vascularization and reduced vascular fenestration after engraftment, partially impairing vascular permeability and glucose delivery to β-cells. We identified primary cilia on endothelial cells as the underlying cause of this regulation, via the vascular endothelial growth factor-A (VEGF-A)/VEGF receptor 2 (VEGFR2) pathway. In vitro silencing of ciliary genes in endothelial cells disrupts VEGF-A/VEGFR2 internalization and downstream signaling. Consequently, key features of angiogenesis including proliferation and migration are attenuated in human BBS4 silenced endothelial cells. We conclude that endothelial cell primary cilia regulate islet vascularization and vascular barrier function via the VEGF-A/VEGFR2 signaling pathway.
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Affiliation(s)
- Yan Xiong
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska University Hospital L1, Stockholm, Sweden
| | - M Julia Scerbo
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
| | - Anett Seelig
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
| | - Francesco Volta
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany.,Technical University Munich, Munich, Germany
| | - Nils O'Brien
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
| | - Andrea Dicker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska University Hospital L1, Stockholm, Sweden
| | - Daniela Padula
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
| | - Heiko Lickert
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany.,Technical University Munich, Munich, Germany.,Deutsches Zentrum für Diabetesforschung, DZD, Munich, Germany
| | - Jantje Mareike Gerdes
- Institute for Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany.,Deutsches Zentrum für Diabetesforschung, DZD, Munich, Germany
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska University Hospital L1, Stockholm, Sweden
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17
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Tian M, Carroll LS, Tang L, Uehara H, Westenfelder C, Ambati BK, Huang Y. Systemic AAV10.COMP-Ang1 rescues renal glomeruli and pancreatic islets in type 2 diabetic mice. BMJ Open Diabetes Res Care 2020; 8:8/1/e000882. [PMID: 32792355 PMCID: PMC7430492 DOI: 10.1136/bmjdrc-2019-000882] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 02/05/2020] [Accepted: 06/14/2020] [Indexed: 12/22/2022] Open
Abstract
INTRODUCTION Diabetic hyperglycemia causes progressive and generalized damage to the microvasculature. In renal glomeruli, this results in the loss of podocytes with consequent loss of constitutive angiopoietin-1 (Ang1) signaling, which is required for stability of the glomerular endothelium. Repeated tail vein injection of adenovirus expressing COMP-Ang1 (a stable bioengineered form of Ang1) was previously reported to improve diabetic glomerular damage despite the liver and lungs being primary targets of adenoviral infection. We thus hypothesized that localizing delivery of sustained COMP-Ang1 to the kidney could increase its therapeutic efficacy and safety for the treatment of diabetes. RESEARCH DESIGN AND METHODS Using AAVrh10 adeno-associated viral capsid with enhanced kidney tropism, we treated 10-week-old uninephrectomized db/db mice (a model of type 2 diabetes) with a single dose of AAVrh10.COMP-Ang1 delivered via the intracarotid artery, compared with untreated diabetic db/db control and non-diabetic db/m mice. RESULTS Surprisingly, both glomerular and pancreatic capillaries expressed COMP-Ang1, compensating for diabetes-induced loss of tissue Ang1. Importantly, treatment with AAVrh10.COMP-Ang1 yielded a significant reduction of glycemia (blood glucose, 241±193 mg/dL vs 576±31 mg/dL; glycosylated hemoglobin, 7.2±1.5% vs 11.3±1.3%) and slowed the progression of albuminuria and glomerulosclerosis in db/db mice by 70% and 61%, respectively, compared with untreated diabetic db/db mice. Furthermore, COMP-Ang1 ameliorated diabetes-induced increases of NF-kBp65, nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase-2 (Nox2), p47phox and productions of myeloperoxidase, the inflammatory markers in both renal and pancreatic tissues, and improved beta-cell density in pancreatic islets. CONCLUSIONS These results highlight the potential of localized Ang1 therapy for treatment of diabetic visceropathies and provide a mechanistic explanation for reported improvements in glucose control via Ang1/Tie2 signaling in the pancreas.
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Affiliation(s)
- Mi Tian
- Internal Medicine/Nephrology, University of Utah, Salt Lake City, Utah, USA
- Internal Medicine/Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Lara S Carroll
- Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Li Tang
- Internal Medicine/Nephrology, University of Utah, Salt Lake City, Utah, USA
| | - Hironori Uehara
- Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | | | - Balamurali K Ambati
- Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Yufeng Huang
- Internal Medicine/Nephrology, University of Utah, Salt Lake City, Utah, USA
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Isenberg JS, Roberts DD. Thrombospondin-1 in maladaptive aging responses: a concept whose time has come. Am J Physiol Cell Physiol 2020; 319:C45-C63. [PMID: 32374675 DOI: 10.1152/ajpcell.00089.2020] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Numerous age-dependent alterations at the molecular, cellular, tissue and organ systems levels underlie the pathophysiology of aging. Herein, the focus is upon the secreted protein thrombospondin-1 (TSP1) as a promoter of aging and age-related diseases. TSP1 has several physiological functions in youth, including promoting neural synapse formation, mediating responses to ischemic and genotoxic stress, minimizing hemorrhage, limiting angiogenesis, and supporting wound healing. These acute functions of TSP1 generally require only transient expression of the protein. However, accumulating basic and clinical data reinforce the view that chronic diseases of aging are associated with accumulation of TSP1 in the extracellular matrix, which is a significant maladaptive contributor to the aging process. Identification of the relevant cell types that chronically produce and respond to TSP1 and the molecular mechanisms that mediate the resulting maladaptive responses could direct the development of therapeutic agents to delay or revert age-associated maladies.
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Affiliation(s)
| | - David D Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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19
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Skog O, Korsgren O. On the dynamics of the human endocrine pancreas and potential consequences for the development of type 1 diabetes. Acta Diabetol 2020; 57:503-511. [PMID: 31520124 PMCID: PMC7093340 DOI: 10.1007/s00592-019-01420-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/04/2019] [Indexed: 12/14/2022]
Abstract
Little is known about the human islet life span, and beta-cell neogenesis is generally considered rare in adults. However, based on available data on beta-cell proliferation, calculations can be made suggesting that the dynamics of the endocrine pancreas is considerable even during adulthood, with islet neogenesis and a sustained increase in size of already formed islets. Islet-associated hemorrhages, frequently observed in most mammals including humans, could account for a considerable loss of islet parenchyma balancing the constant beta-cell proliferation. Notably, in subjects with type 1 diabetes, periductal accumulation of leukocytes and fibrosis is frequently observed, findings that are likely to negatively affect islet neogenesis from endocrine progenitor cells present in the periductal area. Impaired neogenesis would disrupt the balance, result in loss of islet mass, and eventually lead to beta-cell deficiency and compromised glucose metabolism, with increased islet workload and blood perfusion of remaining islets. These changes would impose initiation of a vicious circle further increasing the frequency of vascular events and hemorrhages within remaining islets until the patient eventually loses all beta-cells and becomes c-peptide negative.
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Affiliation(s)
- Oskar Skog
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
| | - Olle Korsgren
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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20
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Lee YB, Kim DH, Roh E, Hong SH, Kim JA, Yoo HJ, Baik SH, Han K, Choi KM. Variability in estimated glomerular filtration rate and the incidence of type 2 diabetes: a nationwide population-based study. BMJ Open Diabetes Res Care 2020; 8:8/1/e001187. [PMID: 32317303 PMCID: PMC7202740 DOI: 10.1136/bmjdrc-2020-001187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/14/2020] [Accepted: 03/28/2020] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE Variability in estimated glomerular filtration rate (eGFR) has been associated with adverse outcomes in patients with diabetes or chronic kidney disease (CKD). However, no previous study has explored the relationship between eGFR variability and type 2 diabetes incidence. RESEARCH DESIGN AND METHODS In this nationwide, longitudinal, cohort study, we investigated the association between eGFR variability and type 2 diabetes risk using the Korean National Health Insurance Service datasets from 2002 to 2017. eGFR variability was calculated using the variability independent of the mean (eGFR-VIM), coefficient of variation (eGFR-CV), standard deviation (eGFR-SD) and average real variability (eGFR-ARV). RESULTS Within 7 673 905.58 person-years of follow-up (mean follow-up: 3.19 years; n=2 402 668), 11 981 cases of incident type 2 diabetes were reported. The HRs and 95% CIs for incident type 2 diabetes increased according to advance in quartiles of eGFR-VIM (HR (95% CI): Q2, 1.068 (1.009 to 1.130); Q3, 1.077 (1.018 to 1.138); Q4, 1.203 (1.139 to 1.270)) even after adjusting for confounding factors including mean eGFR and mean fasting plasma glucose levels. The subgroup analyses according to risk factors as well as analyses using eGFR-CV, eGFR-SD and eGFR-ARV showed consistent results. The association between increased eGFR variability and type 2 diabetes risk was more prominent in men, individuals with dyslipidemia and those with CKD as shown in the subgroup analysis (p for interaction <0.001). CONCLUSIONS Increased eGFR variability may be an independent predictor of type 2 diabetes and might be useful for risk stratification of individuals without diabetes.
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Affiliation(s)
- You-Bin Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
| | - Da Hye Kim
- Department of Biostatistics, Catholic University of Korea, Seoul, Republic of Korea
| | - Eun Roh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
| | - So-Hyeon Hong
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
| | - Jung A Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
| | - Hye Jin Yoo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
| | - Sei Hyun Baik
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
| | - Kyungdo Han
- Department of Biostatistics, Catholic University of Korea, Seoul, Republic of Korea
| | - Kyung Mook Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine and School of Medicine, Seoul, Republic of Korea
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21
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Yao D, GangYi Y, QiNan W. Autophagic dysfunction of β cell dysfunction in type 2 diabetes, a double-edged sword. Genes Dis 2020; 8:438-447. [PMID: 34179308 PMCID: PMC8209341 DOI: 10.1016/j.gendis.2020.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/07/2020] [Accepted: 03/12/2020] [Indexed: 12/19/2022] Open
Abstract
Diabetes is an age-related disease, most of which is type 2 diabetes, and islet β cell dysfunction and insulin resistance are the main mechanisms of type 2 diabetes. Recent studies have revealed that autophagy plays an important role in maintaining the structure and function of islet beta cells and inhibiting insulin resistance and apoptosis induced by oxidative stress. In this review, we discussed the positive and negative effects of autophagy and its dysfunction on type 2 diabetes mellitus, which is the so-called double-edged sword, analysed its possible mechanism, and identified possible research hot spots.
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Affiliation(s)
- Ding Yao
- Endocrinology and Nephrology Department, Chongqing University Cancer Hospital and Chongqing Cancer Institute and Chongqing Cancer Hospital, Chongqing, 400030, PR China
| | - Yang GangYi
- Endocrinology Department, The Second Affiliated Hospital of the Chongqing Medical University, Chongqing, 400010, PR China
| | - Wu QiNan
- Endocrinology and Nephrology Department, Chongqing University Cancer Hospital and Chongqing Cancer Institute and Chongqing Cancer Hospital, Chongqing, 400030, PR China
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22
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Rachdaoui N. Insulin: The Friend and the Foe in the Development of Type 2 Diabetes Mellitus. Int J Mol Sci 2020; 21:ijms21051770. [PMID: 32150819 PMCID: PMC7084909 DOI: 10.3390/ijms21051770] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/29/2020] [Accepted: 03/02/2020] [Indexed: 12/14/2022] Open
Abstract
Insulin, a hormone produced by pancreatic β-cells, has a primary function of maintaining glucose homeostasis. Deficiencies in β-cell insulin secretion result in the development of type 1 and type 2 diabetes, metabolic disorders characterized by high levels of blood glucose. Type 2 diabetes mellitus (T2DM) is characterized by the presence of peripheral insulin resistance in tissues such as skeletal muscle, adipose tissue and liver and develops when β-cells fail to compensate for the peripheral insulin resistance. Insulin resistance triggers a rise in insulin demand and leads to β-cell compensation by increasing both β-cell mass and insulin secretion and leads to the development of hyperinsulinemia. In a vicious cycle, hyperinsulinemia exacerbates the metabolic dysregulations that lead to β-cell failure and the development of T2DM. Insulin and IGF-1 signaling pathways play critical roles in maintaining the differentiated phenotype of β-cells. The autocrine actions of secreted insulin on β-cells is still controversial; work by us and others has shown positive and negative actions by insulin on β-cells. We discuss findings that support the concept of an autocrine action of secreted insulin on β-cells. The hypothesis of whether, during the development of T2DM, secreted insulin initially acts as a friend and contributes to β-cell compensation and then, at a later stage, becomes a foe and contributes to β-cell decompensation will be discussed.
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Affiliation(s)
- Nadia Rachdaoui
- Department of Animal Sciences, Room 108, Foran Hall, Rutgers, the State University of New Jersey, 59 Dudley Rd, New Brunswick, NJ 08901, USA
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23
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Skrypnik K, Bogdański P, Schmidt M, Suliburska J. The Effect of Multispecies Probiotic Supplementation on Iron Status in Rats. Biol Trace Elem Res 2019; 192:234-243. [PMID: 30746586 PMCID: PMC6820595 DOI: 10.1007/s12011-019-1658-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/29/2019] [Indexed: 12/16/2022]
Abstract
A range of interactions between gut microbiota and iron (Fe) metabolism is described. Oral probiotics ameliorate host's iron status. However, this has been proven for single-strain probiotic supplements. Dose-dependence of beneficial probiotic supplementation effect on iron turnover remains unexplored. Our study aimed to investigate the effects of oral multispecies probiotic supplementation in two doses on iron status in rats. Thirty rats were randomized into three groups receiving multispecies probiotic supplement at a daily dose of 2.5 × 109 CFU (PA group, n = 10) and 1 × 1010 CFU (PB group, n = 10) or placebo (KK group, n = 10). After 6 weeks, rats were sacrificed for analysis, blood samples, and organs (the liver, heart, kidneys, spleen, pancreas, femur, testicles, duodenum, and hair) were collected. The total fecal bacteria content was higher in the PB group vs. PA group. Unsaturated iron-binding capacity was higher in the PB group vs. KK group. Serum Fe was lower in both PA and PB vs. KK group. Iron content in the liver was higher in the PB group vs. KK group; in the pancreas, this was higher in the PB group vs. the KK and PA group, and in the duodenum, it was higher in both supplemented groups vs. the KK group. A range of alterations in zinc and copper status and correlations between analyzed parameters were found. Oral multispecies probiotic supplementation exerts dose-independent and beneficial effect on iron bioavailability and duodenal iron absorption in the rat model, induces a dose-independent iron shift from serum and intensifies dose-dependent pancreatic and liver iron uptake.
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Affiliation(s)
- Katarzyna Skrypnik
- Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences, Wojska Polskiego St. 31, 60-624, Poznan, Poland.
| | - Paweł Bogdański
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, Szamarzewskiego St. 82/84, 60-569, Poznan, Poland
| | - Marcin Schmidt
- Department of Food Biotechnology and Microbiology, Poznan University of Life Sciences, Wojska Polskiego St. 48, Poznan, 60-627, Poland
| | - Joanna Suliburska
- Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences, Wojska Polskiego St. 31, 60-624, Poznan, Poland
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Huang C, Wang HY, Wang ME, Hsu MC, Wu YHS, Jiang YF, Wu LS, Jong DS, Chiu CH. Kisspeptin-Activated Autophagy Independently Suppresses Non-Glucose-Stimulated Insulin Secretion from Pancreatic β-Cells. Sci Rep 2019; 9:17451. [PMID: 31767891 PMCID: PMC6877614 DOI: 10.1038/s41598-019-53826-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 11/01/2019] [Indexed: 01/08/2023] Open
Abstract
Previous studies have demonstrated the important role of kisspeptin in impaired glucose-stimulated insulin secretion (GSIS). In addition, it was reported that the activation of autophagy in pancreatic β-cells decreases insulin secretion by selectively degrading insulin granules. However, it is currently unknown whether kisspeptin suppresses GSIS in β-cells by activating autophagy. To investigate the involvement of autophagy in kisspeptin-regulated insulin secretion, we overexpressed Kiss1 in NIT-1 cells to mimic the long-term exposure of pancreatic β-cells to kisspeptin during type 2 diabetes (T2D). Interestingly, our data showed that although kisspeptin potently decreases the intracellular proinsulin and insulin ((pro)insulin) content and insulin secretion of NIT-1 cells, autophagy inhibition using bafilomycin A1 and Atg5 siRNAs only rescues basal insulin secretion, not kisspeptin-impaired GSIS. We also generated a novel in vivo model to investigate the long-term exposure of kisspeptin by osmotic pump. The in vivo data demonstrated that kisspeptin lowers GSIS and (pro)insulin levels and also activated pancreatic autophagy in mice. Collectively, our data demonstrated that kisspeptin suppresses both GSIS and non-glucose-stimulated insulin secretion of pancreatic β-cells, but only non-glucose-stimulated insulin secretion depends on activated autophagic degradation of (pro)insulin. Our study provides novel insights for the development of impaired insulin secretion during T2D progression.
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Affiliation(s)
- Chien Huang
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Hao-Yi Wang
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Mu-En Wang
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.,Department of Pathology, Duke University School of Medicine, Duke Cancer Institute, Duke University, Durham, NC, 27514, USA
| | - Meng-Chieh Hsu
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Yi-Hsieng Samuel Wu
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Yi-Fan Jiang
- Graduate Institute of Molecular and Comparative Pathobiology, School of Medicine, National Taiwan University, Taipei, 10617, Taiwan
| | - Leang-Shin Wu
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - De-Shien Jong
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Chih-Hsien Chiu
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.
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25
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Staels W, Heremans Y, Heimberg H, De Leu N. VEGF-A and blood vessels: a beta cell perspective. Diabetologia 2019; 62:1961-1968. [PMID: 31414144 DOI: 10.1007/s00125-019-4969-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/11/2019] [Indexed: 02/07/2023]
Abstract
Reciprocal signalling between the endothelium and the pancreatic epithelium is crucial for coordinated differentiation of the embryonic endocrine and exocrine pancreas. In the adult pancreas, islets depend on their dense capillary network to adequately respond to changes in plasma glucose levels. Vascular changes contribute to the onset and progression of both type 1 and type 2 diabetes. Impaired revascularisation of islets transplanted in individuals with type 1 diabetes is linked to islet graft failure and graft loss. This review summarises our understanding of the role of vascular endothelial growth factor-A (VEGF-A) and endothelial cells in beta cell development, physiology and disease. In addition, the therapeutic potential of modulating VEGF-A levels in beta and beta-like cells for transplantation is discussed.
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Affiliation(s)
- Willem Staels
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
- Institut Cochin, CNRS, INSERM, Université de Paris, F-75014, Paris, France
| | - Yves Heremans
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Harry Heimberg
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Nico De Leu
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium.
- Department of Endocrinology, UZ Brussel, Brussels, Belgium.
- Department of Endocrinology, ASZ Aalst, Aalst, Belgium.
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Hypoxia Modulates Effects of Fatty Acids on NES2Y Human Pancreatic β-cells. Int J Mol Sci 2019; 20:ijms20143441. [PMID: 31336948 PMCID: PMC6678120 DOI: 10.3390/ijms20143441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/11/2019] [Indexed: 12/27/2022] Open
Abstract
Saturated fatty acids (FAs) induce apoptosis in the human pancreatic NES2Y β-cell line while unsaturated FAs have nearly no detrimental effect. Moreover, unsaturated FAs are capable of inhibiting the pro-apoptotic effect of saturated FAs. Hypoxia is also known to have deleterious effects on β-cells function and viability. In the present study, we have tested the modulatory effect of hypoxia on the effect of FAs on the growth and viability of the human pancreatic NES2Y β-cells. This study represents the first study testing hypoxia effect on effects of FAs in pancreatic β-cells as well as in other cell types. We showed that hypoxia increased the pro-apoptotic effect of saturated stearic acid (SA). Endoplasmic reticulum stress signaling seemed to be involved while redistribution of FA transporters fatty acid translocase/cluster of differentiation 36 (FAT/CD36) and fatty acid-binding protein (FABP) do not seem to be involved in this effect. Hypoxia also strongly decreased the protective effect of unsaturated oleic acid (OA) against the pro-apoptotic effect of SA. Thus, in the presence of hypoxia, OA was unable to save SA-treated β-cells from apoptosis induction. Hypoxia itself had only a weak detrimental effect on NES2Y cells. Our data suggest that hypoxia could represent an important factor in pancreatic β-cell death induced and regulated by FAs and thus in the development of type 2 diabetes mellitus.
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27
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Obata A, Kimura T, Obata Y, Shimoda M, Kinoshita T, Kohara K, Okauchi S, Hirukawa H, Kamei S, Nakanishi S, Mune T, Kaku K, Kaneto H. Vascular endothelial PDPK1 plays a pivotal role in the maintenance of pancreatic beta cell mass and function in adult male mice. Diabetologia 2019; 62:1225-1236. [PMID: 31055616 PMCID: PMC6560212 DOI: 10.1007/s00125-019-4878-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/15/2019] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to elucidate the impact of 3'-phosphoinositide-dependent protein kinase-1 (PDPK1) in vascular endothelial cells on the maintenance of pancreatic beta cell mass and function. METHODS Male vascular endothelial cell-specific Pdpk1-knockout mice (Tie2+/-/Pdpk1flox/flox mice) and their wild-type littermates (Tie2-/-/Pdpk1flox/flox mice; control) were used for this study. At 12 weeks of age, an IPGTT and OGTT were conducted. Pancreatic blood flow was measured under anaesthesia. Thereafter, islet blood flow was measured by the microsphere method. Mice were killed for islet isolation and further functional study and mRNA was extracted from islets. Pancreases were sampled for immunohistochemical analyses. RESULTS During the IPGTT, the blood glucose level was comparable between knockout mice and control flox mice, although serum insulin level was significantly lower in knockout mice. During the OGTT, glucose tolerance deteriorated slightly in knockout mice, accompanied by a decreased serum insulin level. During an IPGTT after pre-treatment with exendin-4 (Ex-4), glucose tolerance was significantly impaired in knockout mice. In fact, glucose-stimulated insulin secretion of isolated islets from knockout mice was significantly reduced compared with control flox mice, and addition of Ex-4 revealed impaired sensitivity to incretin hormones in islets of knockout mice. In immunohistochemical analyses, both alpha and beta cell masses were significantly reduced in knockout mice. In addition, the CD31-positive area was significantly decreased in islets of knockout mice. The proportion of pimonidazole-positive islets was significantly increased in knockout mice. mRNA expression levels related to insulin biosynthesis (Ins1, Ins2, Mafa, Pdx1 and Neurod [also known as Neurod1]) and beta cell function (such as Gck and Slc2a2) were significantly decreased in islets of knockout mice. Microsphere experiments revealed remarkably reduced islet blood flow. In addition, mRNA expression levels of Hif1α (also known as Hif1a) and its downstream factors such as Adm, Eno1, Tpi1 (also known as Ets1), Hmox1 and Vegfa, were significantly increased in islets of knockout mice, indicating that islets of knockout mice were in a more hypoxic state than those of control flox mice. As a result, mRNA expression levels related to adaptive unfolded protein response and endoplasmic reticulum stress-related apoptotic genes were significantly elevated in islets of knockout mice. In addition, inflammatory cytokine levels were increased in islets of knockout mice. Electron microscopy revealed reduced endothelial fenestration and thickening of basal membrane of vascular endothelium in islets of knockout mice. CONCLUSIONS/INTERPRETATION Vascular endothelial PDPK1 plays an important role in the maintenance of pancreatic beta cell mass and function by maintaining vascularity of pancreas and islets and protecting them from hypoxia, hypoxia-related endoplasmic reticulum stress, inflammation and distortion of capillary structure.
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Affiliation(s)
- Atsushi Obata
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan.
| | - Tomohiko Kimura
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Yoshiyuki Obata
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Masashi Shimoda
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Tomoe Kinoshita
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Kenji Kohara
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Seizo Okauchi
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Hidenori Hirukawa
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Shinji Kamei
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Shuhei Nakanishi
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Tomoatsu Mune
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Kohei Kaku
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
| | - Hideaki Kaneto
- Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, 701-0192, Japan
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Jansson L, Carlsson PO. Pancreatic Blood Flow with Special Emphasis on Blood Perfusion of the Islets of Langerhans. Compr Physiol 2019; 9:799-837. [PMID: 30892693 DOI: 10.1002/cphy.c160050] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The pancreatic islets are more richly vascularized than the exocrine pancreas, and possess a 5- to 10-fold higher basal and stimulated blood flow, which is separately regulated. This is reflected in the vascular anatomy of the pancreas where islets have separate arterioles. There is also an insulo-acinar portal system, where numerous venules connect each islet to the acinar capillaries. Both islets and acini possess strong metabolic regulation of their blood perfusion. Of particular importance, especially in the islets, is adenosine and ATP/ADP. Basal and stimulated blood flow is modified by local endothelial mediators, the nervous system as well as gastrointestinal hormones. Normally the responses to the nervous system, especially the parasympathetic and sympathetic nerves, are fairly similar in endocrine and exocrine parts. The islets seem to be more sensitive to the effects of endothelial mediators, especially nitric oxide, which is a permissive factor to maintain the high basal islet blood flow. The gastrointestinal hormones with pancreatic effects mainly influence the exocrine pancreatic blood flow, whereas islets are less affected. A notable exception is incretin hormones and adipokines, which preferentially affect islet vasculature. Islet hormones can influence both exocrine and endocrine blood vessels, and these complex effects are discussed. Secondary changes in pancreatic and islet blood flow occur during several conditions. To what extent changes in blood perfusion may affect the pathogenesis of pancreatic diseases is discussed. Both type 2 diabetes mellitus and acute pancreatitis are conditions where we think there is evidence that blood flow may contribute to disease manifestations. © 2019 American Physiological Society. Compr Physiol 9:799-837, 2019.
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Affiliation(s)
- Leif Jansson
- Uppsala University, Department of Medical Cell Biology, Uppsala, Sweden
| | - Per-Ola Carlsson
- Uppsala University, Department of Medical Cell Biology, Uppsala, Sweden.,Uppsala University, Department of Medical Sciences, Uppsala, Sweden
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29
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Aoyagi K, Itakura M, Fukutomi T, Nishiwaki C, Nakamichi Y, Torii S, Makiyama T, Harada A, Ohara-Imaizumi M. VAMP7 Regulates Autophagosome Formation by Supporting Atg9a Functions in Pancreatic β-Cells From Male Mice. Endocrinology 2018; 159:3674-3688. [PMID: 30215699 DOI: 10.1210/en.2018-00447] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 09/05/2018] [Indexed: 12/24/2022]
Abstract
Dysfunctional mitochondria are observed in β-cells of diabetic patients, which are eventually removed by autophagy. Vesicle-associated membrane protein (VAMP)7, a vesicular SNARE protein, regulates autophagosome formation to maintain mitochondrial homeostasis and control insulin secretion in pancreatic β-cells. However, its molecular mechanism is largely unknown. In this study, we investigated the molecular mechanism of VAMP7-dependent autophagosome formation using VAMP7-deficient β-cells and β-cell-derived Min6 cells. VAMP7 localized in autophagy-related (Atg)9a-resident vesicles of recycling endosomes (REs), which contributed to autophagosome formation, and it interacted with Hrb, Syntaxin16, and SNAP-47. Hrb recruited VAMP7 and Atg9a from the plasma membrane to REs. Syntaxin16 and SNAP-47 mediated autophagosome formation at a step later than the proper localization of VAMP7 to Atg9a-resident vesicles. Knockdown of Hrb, Syntaxin16, and SNAP-47 resulted in defective autophagosome formation, accumulation of dysfunctional mitochondria, and impairment of glucose-stimulated insulin secretion. Our data indicate that VAMP7 and Atg9a are initially recruited to REs to organize VAMP7 and Atg9a-resident vesicles in an Hrb-dependent manner. Additionally, VAMP7 forms a SNARE complex with Syntaxin16 and SNAP-47, which may cause fusions of Atg9a-resident vesicles during autophagosome formation. Thus, VAMP7 participates in autophagosome formation by supporting Atg9a functions that contribute to maintenance of mitochondrial quality.
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Affiliation(s)
- Kyota Aoyagi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Kanagawa, Japan
| | - Toshiyuki Fukutomi
- Department of Pharmacology, Kyorin University School of Medicine, Tokyo, Japan
| | - Chiyono Nishiwaki
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Yoko Nakamichi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Seiji Torii
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
| | - Tomohiko Makiyama
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Mica Ohara-Imaizumi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
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30
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Ceasrine AM, Lin EE, Lumelsky DN, Iyer R, Kuruvilla R. Adrb2 controls glucose homeostasis by developmental regulation of pancreatic islet vasculature. eLife 2018; 7:39689. [PMID: 30303066 PMCID: PMC6200393 DOI: 10.7554/elife.39689] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/07/2018] [Indexed: 12/12/2022] Open
Abstract
A better understanding of processes controlling the development and function of pancreatic islets is critical for diabetes prevention and treatment. Here, we reveal a previously unappreciated function for pancreatic β2-adrenergic receptors (Adrb2) in controlling glucose homeostasis by restricting islet vascular growth during development. Pancreas-specific deletion of Adrb2 results in glucose intolerance and impaired insulin secretion in mice, and unexpectedly, specifically in females. The metabolic phenotypes were recapitulated by Adrb2 deletion from neonatal, but not adult, β-cells. Mechanistically, Adrb2 loss increases production of Vascular Endothelial Growth Factor-A (VEGF-A) in female neonatal β-cells and results in hyper-vascularized islets during development, which in turn, disrupts insulin production and exocytosis. Neonatal correction of islet hyper-vascularization, via VEGF-A receptor blockade, fully rescues functional deficits in glucose homeostasis in adult mutant mice. These findings uncover a regulatory pathway that functions in a sex-specific manner to control glucose metabolism by restraining excessive vascular growth during islet development.
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Affiliation(s)
- Alexis M Ceasrine
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Eugene E Lin
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - David N Lumelsky
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Radhika Iyer
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Rejji Kuruvilla
- Department of Biology, Johns Hopkins University, Baltimore, United States
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31
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Chung JO, Park SY, Cho DH, Chung DJ, Chung MY. Anemia is inversely associated with serum C-peptide concentrations in individuals with type 2 diabetes. Medicine (Baltimore) 2018; 97:e11783. [PMID: 30095635 PMCID: PMC6133397 DOI: 10.1097/md.0000000000011783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The purpose of the study was to test the hypothesis that anemia is related with serum C-peptide concentrations in individuals with type 2 diabetes mellitus (DM).This cross-sectional study was carried out in 1300 individuals with type 2 DM. We measured fasting C-peptide, 2-hour postprandial C-peptide, and postprandial C-peptide minus fasting C-peptide (ΔC-peptide) concentrations. Anemia was defined as hemoglobin (Hb) concentrations <130 g/L in men and <120 g/L in women. Anemia was graded into 2 groups: grade I anemia of Hb concentrations ≥110 g/L and grade II anemia of Hb concentrations <110 g/L.Fasting C-peptide, postprandial C-peptide, and ΔC-peptide concentrations were lower in individuals with anemia. According to the grade of anemia, the average C-peptide concentrations differed significantly after adjusting for other covariates. In the multivariable model, the statistically significant relation between anemia and serum C-peptide concentrations remained after adjusting for confounders, including age, gender, family history of diabetes, body mass index, duration of diabetes, glycated Hb, free fatty acids, hypertension, and hyperlipidemia (fasting C-peptide concentration: β = -0.057, P = .032; postprandial C-peptide concentration: β = -0.098, P < .001; ΔC-peptide concentration: β = -0.095, P < .001).Anemia was inversely associated with serum C-peptide concentrations in individuals with type 2 DM.
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Affiliation(s)
| | - Seon-Young Park
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Chonnam National University Medical School, Dong-Gu, Gwangju, Republic of Korea
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32
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Xu T, Lv Z, Chen Q, Guo M, Wang X, Huang F. Vascular endothelial growth factor over-expressed mesenchymal stem cells-conditioned media ameliorate palmitate-induced diabetic endothelial dysfunction through PI-3K/AKT/m-TOR/eNOS and p38/MAPK signaling pathway. Biomed Pharmacother 2018; 106:491-498. [PMID: 29990837 DOI: 10.1016/j.biopha.2018.06.129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/24/2018] [Accepted: 06/25/2018] [Indexed: 12/17/2022] Open
Abstract
In the pathogenesis of diabetes mellitus (DM), islet microvasculares are severely damaged due to glucolipotoxicity and other reasons. Vascular endothelial growth factor (VEGF) is an indispensable and specific angiogenic factor in the pathogenesis and treatment of diabetic islet microvascular disease. Mesenchymal stem cells (MSCs) are regarded as a promising treatment of diabetes because of their immunosuppressive effect and multipotential differentiation potency. In this study, we tested whether MSCs over-expressing VEGF conditioned medium (MSC-VEGF-CM) could ameliorate pancreatic islet endothelial cells (MS-1) dysfunction induced by a common diabetic inducer palmitate (PA). We found that cell survival and migration were restrained by PA and partly repaired by the pro-protected of MSC-VEGF-CM. Meanwhile, PI-3K/AKT/m-TOR/eNOS and p38/MAPK signaling pathways were also up-regulated. Though apoptosis-related proteins, caspase-3 and caspase-9, had no significantly suppressed between MSC-VEGF-CM and MSC-CM alone, the expression levels of vascular surface factors such as CD31, VE-cadherin, occludin and ICAM-1, were remarkably up-regulated by the pro-protected of MSC-VEGF-CM. Our data suggested that MSC-VEGF-CM had therapeutic effect on the PA-induced dysfunction through the re-activation of PI-3K/AKT/m-TOR/eNOS and p38/MAPK signaling pathways.
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Affiliation(s)
- Tianwei Xu
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Zhengbing Lv
- School of Life Science, Zhejiang Sci-Tech University, Hangzhou, China
| | - Qiuhua Chen
- Intensive Care Unit, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, Nanjing, China
| | - Min Guo
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Xufang Wang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Fengjie Huang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
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Xuan X, Gao F, Ma X, Huang C, Wang Y, Deng H, Wang S, Li W, Yuan L. Activation of ACE2/angiotensin (1-7) attenuates pancreatic β cell dedifferentiation in a high-fat-diet mouse model. Metabolism 2018; 81:83-96. [PMID: 29225087 DOI: 10.1016/j.metabol.2017.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/14/2017] [Accepted: 12/03/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Angiotensin-converting enzyme 2 (ACE2) has been identified in pancreatic islets and can preserve β cells. In this study, we aimed to examine the possible role of ACE2 and its end product, angiotensin 1-7 (A1-7), in reducing β cell dedifferentiation during metabolic stress. METHODS First, a lineage-tracing experiment was performed to track β cells in mice fed a high-fat diet (HFD). Second, the ACE2/A1-7 axis was evaluated in the HFD mouse model. Intraperitoneal glucose tolerance tests (IPGTTs) and intraperitoneal insulin tolerance tests (IPITTs) were conducted. Phenotypic changes in β cells were detected by immunohistochemistry and quantitative real-time PCR. Pancreatic sections were immunostained for vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS). Finally, the effects of the ACE2/A1-7 axis were explored in isolated mouse islets exposed to different concentrations of glucose. Glucose-stimulated insulin release and levels of insulin mRNA and OCT4 mRNA were measured. RESULTS Pancreatic β cell dedifferentiation occurred both in vitro and in vivo in response to metabolic stress and was accompanied by ACE2 reduction. HFD-induced insulin resistance and glucose intolerance were exacerbated in ACE2-knockout (ACE2KO) mice but were alleviated by exogenous A1-7 in C57BL/6J mice. Approximately 20% of β cells were dedifferentiated in ACE2KO mice fed a standard rodent chow diet (SD). A higher percentage of dedifferentiated β cells was detected in ACE2KO mice than in wild-type (WT) mice under HFD conditions. In contrast, the administration of A1-7 alleviated HFD-induced β cell dedifferentiation in C57BL/6J mice. Moreover, the exogenous injection of A1-7 improved microcirculation in islets and decreased the production of iNOS in islets of C57BL/6J mice fed an HFD. Additionally, ACE2 was found to be mainly expressed in α cells of mice, while Mas, the receptor of A1-7, was distributed in β cells. CONCLUSIONS Overall, this study is the first to demonstrate that the ACE2/A1-7/Mas axis may be one of the intra-islet paracrine mechanisms of communication between α and β cells. Enhancing the ACE2/A1-7 axis exerts a protective effect by ameliorating β cell dedifferentiation, and this effect might be partially mediated through improvements in islet microcirculation and suppression of islet iNOS.
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Affiliation(s)
- Xiuping Xuan
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Fei Gao
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Xiaoyi Ma
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chenghu Huang
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Ying Wang
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Hongjun Deng
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Shiqi Wang
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Wencun Li
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Li Yuan
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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Wang Y, Hao N, Lin H, Wang T, Xie J, Yuan Y. Down-regulation of CASK in glucotoxicity-induced insulin dysfunction in pancreatic β cells. Acta Biochim Biophys Sin (Shanghai) 2018; 50:281-287. [PMID: 29293883 DOI: 10.1093/abbs/gmx139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 12/08/2017] [Indexed: 12/28/2022] Open
Abstract
High-glucose level exerts deleterious effects on pancreatic β cells, but the mechanisms remain unclear. Calcium/calmodulin-dependent serine protein kinase (CASK) plays a vital role in neural development and release of neurotransmitters, and probably plays a role in the anchoring of insulin on pancreatic β cell membrane. Hypoxia-inducible factor 1α (HIF1α) is involved in β-cell dysfunction. The aim of this study was to provide some basic evidence that CASK could be involved in glucotoxicity-induced insulin secretion dysfunction mediated by HIF1α in INS-1E cells. CASK overexpression plasmid, HIF1α agonist (CoCl2), and HIF1α selective inhibitor (KC7F2) were used. The results showed that chronic stimulation with high glucose could induce insulin secretion dysfunction in INS-1E β cells. Overexpression of CASK partially reversed the effects of high glucose on insulin secretion. CoCl2 reduced the expression of CASK, but KC7F2 reversed the glucotoxicity-induced CASK level reduction. These results suggested that glucotoxicity-induced insulin secretion defects in INS-1E cells could be mediated by HIF1α via the down-regulation of CASK.
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Affiliation(s)
- Yao Wang
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Southeast University, Nanjing 210009, China
| | - Nana Hao
- Department of Endocrinology, Affiliated Fuyang Hospital of Anhui Medical University, Fuyang 236000, China
| | - Haiyan Lin
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 211166, China
| | - Tianyuan Wang
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Southeast University, Nanjing 210009, China
| | - Jinyang Xie
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Southeast University, Nanjing 210009, China
| | - Yuexing Yuan
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Southeast University, Nanjing 210009, China
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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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Oh YS, Bae GD, Baek DJ, Park EY, Jun HS. Fatty Acid-Induced Lipotoxicity in Pancreatic Beta-Cells During Development of Type 2 Diabetes. Front Endocrinol (Lausanne) 2018; 9:384. [PMID: 30061862 PMCID: PMC6054968 DOI: 10.3389/fendo.2018.00384] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes is caused by chronic insulin resistance and progressive decline in beta-cell function. Optimal beta-cell function and mass is essential for glucose homeostasis and beta-cell impairment leads to the development of diabetes. Elevated levels of circulating fatty acids (FAs) and disturbances in lipid metabolism regulation are associated with obesity, and they are major factors influencing the increase in the incidence of type 2 diabetes. Chronic free FA (FFA) treatment induces insulin resistance and beta-cell dysfunction; therefore, reduction of elevated plasma FFA levels might be an important therapeutic target in obesity and type 2 diabetes. Lipid signals via receptors, and intracellular mechanisms are involved in FFA-induced apoptosis. In this paper, we discuss lipid actions in beta cells, including effects on metabolic pathways and stress responses, to help further understand the molecular mechanisms of lipotoxicity-induced type 2 diabetes.
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Affiliation(s)
- Yoon S. Oh
- Department of Food and Nutrition, Eulji University, Seongnam, South Korea
- *Correspondence: Yoon S. Oh
| | - Gong D. Bae
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
| | - Dong J. Baek
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, South Korea
| | - Eun-Young Park
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, South Korea
| | - Hee-Sook Jun
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
- Gachon Institute of Pharmaceutical Science, College of Pharmacy, Gachon University, Incheon, South Korea
- Gachon University Gil Medical Center, Gachon Medical and Convergence Institute, Incheon, South Korea
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37
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Oxidative Stress in Pancreatic Beta Cell Regeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:1930261. [PMID: 28845211 PMCID: PMC5560096 DOI: 10.1155/2017/1930261] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/28/2017] [Indexed: 01/09/2023]
Abstract
Pancreatic β cell neogenesis and proliferation during the neonatal period are critical for the generation of sufficient pancreatic β cell mass/reserve and have a profound impact on long-term protection against type 2 diabetes (T2D). Oxidative stress plays an important role in β cell neogenesis, proliferation, and survival under both physiological and pathophysiological conditions. Pancreatic β cells are extremely susceptible to oxidative stress due to a high endogenous production of reactive oxygen species (ROS) and a low expression of antioxidative enzymes. In this review, we summarize studies describing the critical roles and the mechanisms of how oxidative stress impacts β cell neogenesis and proliferation. In addition, the effects of antioxidant supplements on reduction of oxidative stress and increase of β cell proliferation are discussed. Exploring the roles and the potential therapeutic effects of antioxidants in the process of β cell regeneration would provide novel perspectives to preserve and/or expand pancreatic β cell mass for the treatment of T2D.
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Varshney R, Gupta S, Roy P. Cytoprotective effect of kaempferol against palmitic acid-induced pancreatic β-cell death through modulation of autophagy via AMPK/mTOR signaling pathway. Mol Cell Endocrinol 2017; 448:1-20. [PMID: 28237721 DOI: 10.1016/j.mce.2017.02.033] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 01/31/2017] [Accepted: 02/20/2017] [Indexed: 01/07/2023]
Abstract
Lipotoxicity of pancreatic β-cells is the pathological manifestation of obesity-linked type II diabetes. We intended to determine the cytoprotective effect of kaempferol on pancreatic β-cells undergoing apoptosis in palmitic acid (PA)-stressed condition. The data showed that kaempferol treatment increased cell viability and anti-apoptotic activity in PA-stressed RIN-5F cells and murine pancreatic islets. Furthermore, kaempferol's ability to instigate autophagy was illustrated by MDC-LysoTracker red staining and TEM analysis which corroborated well with the observed increase in LC3 puncta and LC3-II protein expressions along with the concomitant decline in p62 expression. Apart from this, the data showed that kaempferol up/down-regulates AMPK/mTOR phosphorylation respectively. Subsequently, upon inhibition of AMPK phosphorylation by AMPK inhibitors, kaempferol-mediated autophagy was abolished which further led to the decline in β-cell survival. Such observations collectively lead to the conclusion that, kaempferol exerts its cytoprotective role against lipotoxicity by activation of autophagy via AMPK/mTOR pathway.
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Affiliation(s)
- Ritu Varshney
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand, India
| | - Sumeet Gupta
- College of Pharmacy, Maharishi Markandeshwar University, Mullana, Ambala 133 207, Haryana, India
| | - Partha Roy
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand, India.
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Hogan MF, Hull RL. The islet endothelial cell: a novel contributor to beta cell secretory dysfunction in diabetes. Diabetologia 2017; 60:952-959. [PMID: 28396983 PMCID: PMC5505567 DOI: 10.1007/s00125-017-4272-9] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/02/2017] [Indexed: 11/25/2022]
Abstract
The pancreatic islet is highly vascularised, with an extensive capillary network. In addition to providing nutrients and oxygen to islet endocrine cells and transporting hormones to the peripheral circulation, islet capillaries (comprised primarily of islet endothelial cells) are an important source of signals that enhance survival and function of the islet beta cell. In type 2 diabetes, and animal models thereof, evidence exists of morphological and functional abnormalities in these islet endothelial cells. In diabetes, islet capillaries are thickened, dilated and fragmented, and islet endothelial cells express markers of inflammation and activation. In vitro data suggest that this dysfunctional islet endothelial phenotype may contribute to impaired insulin release from the beta cell. This review examines potential candidate molecules that may mediate the positive effects of islet endothelial cells on beta cell survival and function under normal conditions. Further, it explores possible mechanisms underlying the development of islet endothelial dysfunction in diabetes and reviews therapeutic options for ameliorating this aspect of the islet lesion in type 2 diabetes. Finally, considerations regarding differences between human and rodent islet vasculature and the potentially unforeseen negative consequences of strategies to expand the islet vasculature, particularly under diabetic conditions, are discussed.
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Affiliation(s)
- Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System (151), 1660 South Columbian Way, Seattle, WA, 98108, USA
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System (151), 1660 South Columbian Way, Seattle, WA, 98108, USA.
- Department of Medicine, University of Washington, Seattle, WA, USA.
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40
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Gerber PA, Rutter GA. The Role of Oxidative Stress and Hypoxia in Pancreatic Beta-Cell Dysfunction in Diabetes Mellitus. Antioxid Redox Signal 2017; 26:501-518. [PMID: 27225690 PMCID: PMC5372767 DOI: 10.1089/ars.2016.6755] [Citation(s) in RCA: 385] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 05/25/2016] [Indexed: 12/16/2022]
Abstract
SIGNIFICANCE Metabolic syndrome is a frequent precursor of type 2 diabetes mellitus (T2D), a disease that currently affects ∼8% of the adult population worldwide. Pancreatic beta-cell dysfunction and loss are central to the disease process, although understanding of the underlying molecular mechanisms is still fragmentary. Recent Advances: Oversupply of nutrients, including glucose and fatty acids, and the subsequent overstimulation of beta cells, are believed to be an important contributor to insulin secretory failure in T2D. Hypoxia has also recently been implicated in beta-cell damage. Accumulating evidence points to a role for oxidative stress in both processes. Although the production of reactive oxygen species (ROS) results from enhanced mitochondrial respiration during stimulation with glucose and other fuels, the expression of antioxidant defense genes is unusually low (or disallowed) in beta cells. CRITICAL ISSUES Not all subjects with metabolic syndrome and hyperglycemia go on to develop full-blown diabetes, implying an important role in disease risk for gene-environment interactions. Possession of common risk alleles at the SLC30A8 locus, encoding the beta-cell granule zinc transporter ZnT8, may affect cytosolic Zn2+ concentrations and thus susceptibility to hypoxia and oxidative stress. FUTURE DIRECTIONS Loss of normal beta-cell function, rather than total mass, is increasingly considered to be the major driver for impaired insulin secretion in diabetes. Better understanding of the role of oxidative changes, its modulation by genes involved in disease risk, and effects on beta-cell identity may facilitate the development of new therapeutic strategies to this disease. Antioxid. Redox Signal. 26, 501-518.
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Affiliation(s)
- Philipp A. Gerber
- Department of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Zurich, Zurich, Switzerland
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, United Kingdom
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41
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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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Shah P, Lueschen N, Ardestani A, Oberholzer J, Olerud J, Carlsson PO, Maedler K. Angiopoetin-2 Signals Do Not Mediate the Hypervascularization of Islets in Type 2 Diabetes. PLoS One 2016; 11:e0161834. [PMID: 27617438 PMCID: PMC5019443 DOI: 10.1371/journal.pone.0161834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 08/12/2016] [Indexed: 12/12/2022] Open
Abstract
AIMS Changes in the islet vasculature have been implicated in the regulation of β-cell survival and function during the progression to type 2 diabetes (T2D). Failure of the β-cell to compensate for the increased insulin demand in obesity eventually leads to diabetes; as a result of the complex interplay of genetic and environmental factors (e.g. ongoing inflammation within the islets) and impaired vascular function. The Angiopoietin/Tie (Ang/Tie) angiogenic system maintains vasculature and is closely related to organ inflammation and angiogenesis. In this study we aimed to identify whether the vessel area within the islets changes in diabetes and whether such changes would be triggered by the Tie-antagonist Ang-2. METHODS Immunohistochemical and qPCR analyses to follow islet vascularization and Ang/Tie levels were performed in human pancreatic autopsies and isolated human and mouse islets. The effect of Ang-2 was assessed in β-cell-specific Ang-2 overexpressing mice during high fat diet (HFD) feeding. RESULTS Islet vessel area was increased in autopsy pancreases from patients with T2D. The vessel markers Tie-1, Tie-2 and CD31 were upregulated in mouse islets upon HFD feeding from 8 to 24 weeks. Ang-2 was transiently upregulated in mouse islets at 8 weeks of HFD and under glucolipotoxic conditions (22.2 mM glucose/ 0.5 mM palmitate) in vitro in human and mouse islets, in contrast to its downregulation by cytokines (IL-1β, IFN-ɣ and TNF-α). Ang-1 on the other hand was oppositely regulated, with a significant loss under glucolipotoxic condition, a trend to reduce in islets from patients with T2D and an upregulation by cytokines. Modulation of such changes in Ang-2 by its overexpression or the inhibition of its receptor Tie-2 impaired β-cell function at basal conditions but protected islets from cytokine induced apoptosis. In vivo, β-cell-specific Ang-2 overexpression in mice induced hypervascularization under normal diet but contrastingly led to hypovascularized islets in response to HFD together with increased apoptosis and reduced β-cell mass. CONCLUSIONS Islet hypervascularization occurs in T2D. A balanced expression of the Ang1/Ang2 system is important for islet physiology. Ang-2 prevents β-cell mass and islet vascular adaptation in response to HFD feeding with no major influence on glucose homeostasis.
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Affiliation(s)
- Payal Shah
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Navina Lueschen
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Amin Ardestani
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Jose Oberholzer
- Division of Transplantation, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Johan Olerud
- Department of Immunology, Genetics and pathology, Uppsala University, Uppsala, Sweden
| | - Per-Ola Carlsson
- Department of Medical cell biology and Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Kathrin Maedler
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany,German Center for Diabetes Research (DZD) project partner, University of Bremen, Bremen, Germany,* E-mail:
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Bensellam M, Maxwell EL, Chan JY, Luzuriaga J, West PK, Jonas JC, Gunton JE, Laybutt DR. Hypoxia reduces ER-to-Golgi protein trafficking and increases cell death by inhibiting the adaptive unfolded protein response in mouse beta cells. Diabetologia 2016; 59:1492-1502. [PMID: 27039902 DOI: 10.1007/s00125-016-3947-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/16/2016] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Hypoxia may contribute to beta cell failure in type 2 diabetes and islet transplantation. The adaptive unfolded protein response (UPR) is required for endoplasmic reticulum (ER) homeostasis. Here we investigated whether or not hypoxia regulates the UPR in beta cells and the role the adaptive UPR plays during hypoxic stress. METHODS Mouse islets and MIN6 cells were exposed to various oxygen (O2) tensions. DNA-damage inducible transcript 3 (DDIT3), hypoxia-inducible transcription factor (HIF)1α and HSPA5 were knocked down using small interfering (si)RNA; Hspa5 was also overexpressed. db/db mice were used. RESULTS Hypoxia-response genes were upregulated in vivo in the islets of diabetic, but not prediabetic, db/db mice. In isolated mouse islets and MIN6 cells, O2 deprivation (1-5% vs 20%; 4-24 h) markedly reduced the expression of adaptive UPR genes, including Hspa5, Hsp90b1, Fkbp11 and spliced Xbp1. Coatomer protein complex genes (Copa, Cope, Copg [also known as Copg1], Copz1 and Copz2) and ER-to-Golgi protein trafficking were also reduced, whereas apoptotic genes (Ddit3, Atf3 and Trb3 [also known as Trib3]), c-Jun N-terminal kinase (JNK) phosphorylation and cell death were increased. Inhibition of JNK, but not HIF1α, restored adaptive UPR gene expression and ER-to-Golgi protein trafficking while protecting against apoptotic genes and cell death following hypoxia. DDIT3 knockdown delayed the loss of the adaptive UPR and partially protected against hypoxia-induced cell death. The latter response was prevented by HSPA5 knockdown. Finally, Hspa5 overexpression significantly protected against hypoxia-induced cell death. CONCLUSIONS/INTERPRETATION Hypoxia inhibits the adaptive UPR in beta cells via JNK and DDIT3 activation, but independently of HIF1α. Downregulation of the adaptive UPR contributes to reduced ER-to-Golgi protein trafficking and increased beta cell death during hypoxic stress.
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Affiliation(s)
- Mohammed Bensellam
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Emma L Maxwell
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jeng Yie Chan
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jude Luzuriaga
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Phillip K West
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jean-Christophe Jonas
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium
| | - Jenny E Gunton
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
- Westmead Hospital, Sydney, NSW, Australia
- The Westmead Millennium Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - D Ross Laybutt
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia.
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Brissova M, Shostak A, Fligner CL, Revetta FL, Washington MK, Powers AC, Hull RL. Human Islets Have Fewer Blood Vessels than Mouse Islets and the Density of Islet Vascular Structures Is Increased in Type 2 Diabetes. J Histochem Cytochem 2015. [PMID: 26216139 DOI: 10.1369/0022155415573324] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Human and rodent islets differ substantially in several features, including architecture, cell composition, gene expression and some aspects of insulin secretion. Mouse pancreatic islets are highly vascularized with interactions between islet endothelial and endocrine cells being important for islet cell differentiation and function. To determine whether human islets have a similar high degree of vascularization and whether this is altered with diabetes, we examined the vascularization of islets from normal human subjects, subjects with type 2 diabetes (T2D), and normal mice. Using an integrated morphometry approach to quantify intra-islet capillary density in human and mouse pancreatic sections, we found that human islets have five-fold fewer vessels per islet area than mouse islets. Islets in pancreatic sections from T2D subjects showed capillary thickening, some capillary fragmentation and had increased vessel density as compared with non-diabetic controls. These changes in islet vasculature in T2D islets appeared to be associated with amyloid deposition, which was noted in islets from 8/9 T2D subjects (and occupied 14% ± 4% of islet area), especially around the intra-islet capillaries. The physiological implications of the differences in the angioarchitecture of mouse and human islets are not known. Islet vascular changes in T2D may exacerbate β cell/islet dysfunction and β cell loss.
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Affiliation(s)
- Marcela Brissova
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville Medical Center, Tennessee (MB, AS, ACP)
| | - Alena Shostak
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville Medical Center, Tennessee (MB, AS, ACP)
| | - Corinne L Fligner
- Department of Pathology, University of Washington, Seattle, Washington (CLF)
| | - Frank L Revetta
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee (FLR, MKW)
| | - Mary K Washington
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee (FLR, MKW)
| | - Alvin C Powers
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville Medical Center, Tennessee (MB, AS, ACP),Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee (ACP),VA Tennessee Valley Healthcare System, Nashville, Tennessee (ACP)
| | - Rebecca L Hull
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee (FLR, MKW),Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (RLH)
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45
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Feng ZC, Popell A, Li J, Silverstein J, Oakie A, Yee SP, Wang R. c-Kit Receptor Signaling Regulates Islet Vasculature, β-Cell Survival, and Function In Vivo. Diabetes 2015; 64:3852-66. [PMID: 26253609 DOI: 10.2337/db15-0054] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 07/25/2015] [Indexed: 11/13/2022]
Abstract
The receptor tyrosine kinase c-Kit plays an integral role in maintaining β-cell mass and function. Although c-Kit receptor signaling promotes angiogenesis in multiple cell types, its role in islet vasculature is unknown. This study examines the effects of c-Kit-mediated vascular endothelial growth factor isoform A (VEGF-A) and islet vascularization on β-cell function and survival using in vitro cell culture and in vivo mouse models. In cultured INS-1 cells and primary islets, c-Kit regulates VEGF-A expression via the Akt/mammalian target of rapamycin (mTOR) signaling pathway. Juvenile mice with mutated c-Kit (c-Kit(Wv/+)) showed impaired islet vasculature and β-cell dysfunction, while restoring c-Kit expression in β-cells of c-Kit(Wv/+) mice rescued islet vascular defects through modulation of the Akt/mTOR/VEGF-A pathway, indicating that c-Kit signaling in β-cells is a required regulator for maintaining normal islet vasculature. Furthermore, β-cell-specific c-Kit overexpression (c-KitβTg) in aged mice showed significantly increased islet vasculature and β-cell function, but, when exposed to a long-term high-fat diet, c-Kit signaling in c-KitβTg mice induced substantial vascular remodeling, which resulted in increased islet inflammatory responses and β-cell apoptosis. These results suggest that c-Kit-mediated VEGF-A action in β-cells plays a pivotal role in maintaining islet vascularization and function.
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Affiliation(s)
- Zhi-Chao Feng
- Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Alex Popell
- Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Jinming Li
- Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Jenna Silverstein
- Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Amanda Oakie
- Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada Department of Pathology, University of Western Ontario, London, Ontario, Canada
| | - Siu-Pok Yee
- Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT
| | - Rennian Wang
- Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada Department of Medicine, University of Western Ontario, London, Ontario, Canada
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46
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Janikiewicz J, Hanzelka K, Dziewulska A, Kozinski K, Dobrzyn P, Bernas T, Dobrzyn A. Inhibition of SCD1 impairs palmitate-derived autophagy at the step of autophagosome-lysosome fusion in pancreatic β-cells. J Lipid Res 2015; 56:1901-11. [PMID: 26293158 DOI: 10.1194/jlr.m059980] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Indexed: 01/22/2023] Open
Abstract
Autophagy is indispensable for the proper architecture and flawless functioning of pancreatic β-cells. A growing body of evidence indicates reciprocal communication between autophagic pathways, apoptosis, and intracellular lipids. The way in which elevated levels of free saturated or unsaturated FAs contribute to progressive β-cell failure remains incompletely understood. Stearoyl-CoA desaturase (SCD)1, a key regulatory enzyme in biosynthesis of MUFAs, was shown to play an important role in regulation of β-cell function. Here, we investigated whether SCD1 activity is engaged in palmitate-induced pancreatic β-cell autophagy. We found augmented apoptosis and diminished autophagy upon cotreatment of INS-1E cells with palmitate and an SCD1 inhibitor. Furthermore, we found that additional treatment of the cells with monensin, an inhibitor of autophagy at the step of fusion, exacerbates palmitate-induced apoptosis. Accordingly, diminished SCD1 activity affected the accumulation, composition, and saturation status of cellular membrane phospholipids and neutral lipids. Such an effect was accompanied by aberrant endoplasmic reticulum stress, mitochondrial injury, and decreases in insulin secretion and cell proliferation. Our data reveal a novel mechanism by which the inhibition of SCD1 activity affects autophagosome-lysosome fusion because of perturbations in cellular membrane integrity, thus leading to an aberrant stress response and β-cell failure.
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Affiliation(s)
- Justyna Janikiewicz
- Laboratories of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Hanzelka
- Laboratories of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Anna Dziewulska
- Laboratories of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Kamil Kozinski
- Laboratories of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Pawel Dobrzyn
- Medical Molecular Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Tytus Bernas
- Functional and Structural Tissue Imaging, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Dobrzyn
- Laboratories of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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47
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Usborne A, Byrd RA, Meehan J, Blackbourne JL, Sullivan J, Poitout-Belissent F, Prefontaine A, Martin JA, Vahle JL. An Investigative Study of Pancreatic Exocrine Biomarkers, Histology, and Histomorphometry in Male Zucker Diabetic Fatty (ZDF) Rats Given Dulaglutide by Subcutaneous Injection Twice Weekly for 13 Weeks. Toxicol Pathol 2015; 43:1093-102. [PMID: 26269615 DOI: 10.1177/0192623315596857] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) receptor agonist therapy has been implicated as a possible risk factor for acute pancreatitis in patients with type 2 diabetes. Dulaglutide is a long-acting GLP-1 receptor agonist in development for treatment of type 2 diabetes. The effects of dulaglutide were evaluated in male Zucker diabetic fatty (ZDF) rats to examine whether dulaglutide may induce or modulate pancreatitis. Rats were randomized to dose groups receiving twice-weekly subcutaneously administered dulaglutide 0.5, 1.5, and 5.0 mg/kg/dose (corresponding human plasma exposures following twice-weekly dosing are 3-, 8-, and 30-fold, respectively) for 13 weeks or to vehicle control. Following termination, serially trimmed sections of pancreases were stained with hematoxylin and eosin or co-stained with an epithelial marker and a marker of either proliferation or apoptosis. Efficacious reductions in glucose and hemoglobin A1c occurred at all dulaglutide doses. Lipase activity was unaffected, and there were modest increases in total and pancreatic amylase activities at all doses without individual microscopic inflammatory correlates. Microscopic dulaglutide-related pancreatic changes included increased interlobular ductal epithelium without ductal cell proliferation (≥0.5 mg/kg), increased acinar atrophy with/without inflammation (≥1.5 mg/kg), and increased incidence/severity of neutrophilic acinar pancreatic inflammation (5.0 mg/kg). In summary, dulaglutide treatment was associated with mild alterations in ductal epithelium and modest exacerbation of spontaneous lesions of the exocrine pancreas typically found in the ZDF rat model.
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Affiliation(s)
- Amy Usborne
- Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Richard A Byrd
- Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - James Meehan
- Charles River Laboratories, Preclinical Services Montreal, Senneville, Quebec, Canada
| | - Jamie L Blackbourne
- Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - John Sullivan
- Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | | | - Annick Prefontaine
- Charles River Laboratories, Preclinical Services Montreal, Senneville, Quebec, Canada
| | - Jennifer A Martin
- Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - John L Vahle
- Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, Indiana, USA
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48
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Morris DL. Minireview: Emerging Concepts in Islet Macrophage Biology in Type 2 Diabetes. Mol Endocrinol 2015; 29:946-62. [PMID: 26001058 DOI: 10.1210/me.2014-1393] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Chronic systemic inflammation is a hallmark feature of obesity and type 2 diabetes. Both resident and recruited islet macrophages contribute to the proinflammatory milieu of the diabetic islet. However, macrophages also appear to be critical for β-cell formation during development and support β-cell replication in experimental models of pancreas regeneration. In light of these findings, perhaps macrophages in the islet need to be viewed more as a fulcrum where deleterious inflammatory activation is balanced with beneficial tissue repair processes. Undoubtedly, defining the factors that contribute to the ontogeny, heterogeneity, and functionality of macrophages in normal, diseased, and regenerating islets will be necessary to determine whether that fulcrum can be moved to preserve functional β-cell mass in persons with diabetes. The intent of this review is to introduce the reader to emerging concepts of islet macrophage biology that may challenge the perception that macrophage accumulation in islets is merely a pathological feature of type 2 diabetes.
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Affiliation(s)
- David L Morris
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
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49
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Janikiewicz J, Hanzelka K, Kozinski K, Kolczynska K, Dobrzyn A. Islet β-cell failure in type 2 diabetes--Within the network of toxic lipids. Biochem Biophys Res Commun 2015; 460:491-6. [PMID: 25843796 DOI: 10.1016/j.bbrc.2015.03.153] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/11/2022]
Abstract
Obesity-related type 2 diabetes develops in individuals with the onset of β-cell dysfunction. Pancreatic islet lipotoxicity is now recognized as a primary reason for the onset and progression of the disease. Such dysfunction is reflected by the aberrant secretory capacity and detrimental loss of β-cell mass and survival. Elevated circulating serum fatty acid levels and disordered lipid metabolism management are particularly interesting in the search for biologically relevant triggers of β-cell demise. Herein, we review various types of toxic lipid metabolites that may play a significant role in pancreatic islet failure. The lipotoxic effect on β-cells depends on the type of lipid mediator (e.g., long-chain fatty acids, diacylglycerols, ceramides, phospholipids), cellular location of its action (e.g., endoplasmic reticulum, mitochondria), and associated-organelle conditions (e.g., membranes, vesicles). We also discuss various aspects of lipid action in β-cells, including effects on metabolic pathways, stress responses (e.g., oxidative stress, endoplasmic reticulum stress, and autophagy), and gene expression.
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Affiliation(s)
- Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Katarzyna Hanzelka
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Kamil Kozinski
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Katarzyna Kolczynska
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland.
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50
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Carlsson PO, Jansson L. Disruption of insulin receptor signaling in endothelial cells shows the central role of an intact islet blood flow for in vivo β-cell function. Diabetes 2015; 64:700-2. [PMID: 25713194 DOI: 10.2337/db14-1523] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Per-Ola Carlsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Leif Jansson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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