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Liang X, Mounier N, Apfel N, Khalid S, Frayling TM, Bowden J. Using clustering of genetic variants in Mendelian randomization to interrogate the causal pathways underlying multimorbidity from a common risk factor. Genet Epidemiol 2024. [PMID: 39138631 DOI: 10.1002/gepi.22582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/17/2024] [Accepted: 07/09/2024] [Indexed: 08/15/2024]
Abstract
Mendelian randomization (MR) is an epidemiological approach that utilizes genetic variants as instrumental variables to estimate the causal effect of an exposure on a health outcome. This paper investigates an MR scenario in which genetic variants aggregate into clusters that identify heterogeneous causal effects. Such variant clusters are likely to emerge if they affect the exposure and outcome via distinct biological pathways. In the multi-outcome MR framework, where a shared exposure causally impacts several disease outcomes simultaneously, these variant clusters can provide insights into the common disease-causing mechanisms underpinning the co-occurrence of multiple long-term conditions, a phenomenon known as multimorbidity. To identify such variant clusters, we adapt the general method of agglomerative hierarchical clustering to multi-sample summary-data MR setup, enabling cluster detection based on variant-specific ratio estimates. Particularly, we tailor the method for multi-outcome MR to aid in elucidating the causal pathways through which a common risk factor contributes to multiple morbidities. We show in simulations that our "MR-AHC" method detects clusters with high accuracy, outperforming the existing methods. We apply the method to investigate the causal effects of high body fat percentage on type 2 diabetes and osteoarthritis, uncovering interconnected cellular processes underlying this multimorbid disease pair.
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Affiliation(s)
- Xiaoran Liang
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Ninon Mounier
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Nicolas Apfel
- Department of Economics, University of Southampton, Southampton, UK
| | - Sara Khalid
- Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Timothy M Frayling
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
- Department of Genetic Medicine and Development, Faculty of Medicine, CMU, Geneva, Switzerland
| | - Jack Bowden
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
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Rivera Nieves AM, Wauford BM, Fu A. Mitochondrial bioenergetics, metabolism, and beyond in pancreatic β-cells and diabetes. Front Mol Biosci 2024; 11:1354199. [PMID: 38404962 PMCID: PMC10884328 DOI: 10.3389/fmolb.2024.1354199] [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: 12/12/2023] [Accepted: 01/17/2024] [Indexed: 02/27/2024] Open
Abstract
In Type 1 and Type 2 diabetes, pancreatic β-cell survival and function are impaired. Additional etiologies of diabetes include dysfunction in insulin-sensing hepatic, muscle, and adipose tissues as well as immune cells. An important determinant of metabolic health across these various tissues is mitochondria function and structure. This review focuses on the role of mitochondria in diabetes pathogenesis, with a specific emphasis on pancreatic β-cells. These dynamic organelles are obligate for β-cell survival, function, replication, insulin production, and control over insulin release. Therefore, it is not surprising that mitochondria are severely defective in diabetic contexts. Mitochondrial dysfunction poses challenges to assess in cause-effect studies, prompting us to assemble and deliberate the evidence for mitochondria dysfunction as a cause or consequence of diabetes. Understanding the precise molecular mechanisms underlying mitochondrial dysfunction in diabetes and identifying therapeutic strategies to restore mitochondrial homeostasis and enhance β-cell function are active and expanding areas of research. In summary, this review examines the multidimensional role of mitochondria in diabetes, focusing on pancreatic β-cells and highlighting the significance of mitochondrial metabolism, bioenergetics, calcium, dynamics, and mitophagy in the pathophysiology of diabetes. We describe the effects of diabetes-related gluco/lipotoxic, oxidative and inflammation stress on β-cell mitochondria, as well as the role played by mitochondria on the pathologic outcomes of these stress paradigms. By examining these aspects, we provide updated insights and highlight areas where further research is required for a deeper molecular understanding of the role of mitochondria in β-cells and diabetes.
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Affiliation(s)
- Alejandra María Rivera Nieves
- Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Brian Michael Wauford
- Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Accalia Fu
- Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
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Yang J, Zou Y, Lv X, Chen J, Cui C, Song J, Yang M, Hu H, Gao J, Xia L, Wang L, Chen L, Hou X. Didymin protects pancreatic beta cells by enhancing mitochondrial function in high-fat diet-induced impaired glucose tolerance. Diabetol Metab Syndr 2024; 16:7. [PMID: 38172956 PMCID: PMC10762818 DOI: 10.1186/s13098-023-01244-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
PURPOSE Prolonged exposure to plasma free fatty acids (FFAs) leads to impaired glucose tolerance (IGT) which can progress to type 2 diabetes (T2D) in the absence of timely and effective interventions. High-fat diet (HFD) leads to chronic inflammation and oxidative stress, impairing pancreatic beta cell (PBC) function. While Didymin, a flavonoid glycoside derived from citrus fruits, has beneficial effects on inflammation dysfunction, its specific role in HFD-induced IGT remains yet to be elucidated. Hence, this study aims to investigate the protective effects of Didymin on PBCs. METHODS HFD-induced IGT mice and INS-1 cells were used to explore the effect and mechanism of Didymin in alleviating IGT. Serum glucose and insulin levels were measured during the glucose tolerance and insulin tolerance tests to evaluate PBC function and insulin resistance. Next, RNA-seq analysis was performed to identify the pathways potentially influenced by Didymin in PBCs. Furthermore, we validated the effects of Didymin both in vitro and in vivo. Mitochondrial electron transport inhibitor (Rotenone) was used to further confirm that Didymin exerts its ameliorative effect by enhancing mitochondria function. RESULTS Didymin reduces postprandial glycemia and enhances 30-minute postprandial insulin levels in IGT mice. Moreover, Didymin was found to enhance mitochondria biogenesis and function, regulate insulin secretion, and alleviate inflammation and apoptosis. However, these effects were abrogated with the treatment of Rotenone, indicating that Didymin exerts its ameliorative effect by enhancing mitochondria function. CONCLUSIONS Didymin exhibits therapeutic potential in the treatment of HFD-induced IGT. This beneficial effect is attributed to the amelioration of PBC dysfunction through improved mitochondrial function.
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Affiliation(s)
- Jingwen Yang
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Ying Zou
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Xiaoyu Lv
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Jun Chen
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Chen Cui
- Department of Endocrinology, The Second Hospital of Shandong University, Jinan, China
| | - Jia Song
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Mengmeng Yang
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Huiqing Hu
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Jing Gao
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Longqing Xia
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Liming Wang
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
| | - Li Chen
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, China
- National Key Laboratory for Innovation and Transformation of Luobing Theory, Jinan, China
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, Jinan, China
| | - Xinguo Hou
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, 250012, Jinan, Shandong, China.
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, China.
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, China.
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, China.
- National Key Laboratory for Innovation and Transformation of Luobing Theory, Jinan, China.
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, Jinan, China.
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Al-Romaiyan A, Persaud SJ, Jones PM. Identification of Potential Plant-Derived Pancreatic Beta-Cell-Directed Agents Using New Custom-Designed Screening Method: Gymnema sylvestre as an Example. Molecules 2023; 29:194. [PMID: 38202777 PMCID: PMC10780566 DOI: 10.3390/molecules29010194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/23/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Folk medicines are attractive therapeutic agents for treating type 2 diabetes mellitus (T2DM). Most plant extracts that have been suggested to restore β-cells function were tested in vivo. Some only have been tested in vitro to determine whether they have a direct effect on β-cells islets of Langerhans. Currently, there are no defined criteria for screening of β-cell-directed plant-based remedies as potential antidiabetic agents. SUMMARY In this review, we have identified certain criteria/characteristics that can be used to generate a "screening portfolio" to identify plant extracts as potential β-cell-directed agents for the treatment of T2DM. To validate our screening method, we studied the potential therapeutic efficacy of a Gymnema sylvestre (GS) extract using the screening criteria detailed in the review. Six criteria have been identified and validated using OSA®, a GS extract. By using this screening method, we show that OSA® fulfilled most of the criteria identified for an effective β-cell-directed antidiabetic therapy, being an effective insulin-releasing agent at nontoxic concentrations; maintaining β-cell insulin content by stimulating a concomitant increase in insulin gene transcription; maintaining β-cell mass by protecting against apoptosis; and being effective at maintaining normoglycemia in vivo in a mouse model and a human cohort with T2DM. KEY MESSAGES The present review has highlighted the importance of having a screening portfolio for plant extracts that have potential antidiabetic effects in the treatment of T2DM. We propose that this screening method should be adopted for future studies to identify new β-cell-directed antidiabetic plant derived agents.
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Affiliation(s)
- Altaf Al-Romaiyan
- Department of Pharmacology and Therapeutics, College of Pharmacy, Kuwait University, Jabriya 046302, Kuwait
| | - Shanta J. Persaud
- Department of Diabetes, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences and Medicine, King’s College London, London SE1 1UL, UK; (S.J.P.); (P.M.J.)
| | - Peter M. Jones
- Department of Diabetes, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences and Medicine, King’s College London, London SE1 1UL, UK; (S.J.P.); (P.M.J.)
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McKimpson WM, Kitsis RN. Inducing and measuring apoptotic cell death in mouse pancreatic β-cells and in isolated islets. STAR Protoc 2022; 3:101287. [PMID: 35719268 PMCID: PMC9200107 DOI: 10.1016/j.xpro.2022.101287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Type 2 diabetes is mediated by insulin resistance and pancreatic β-cell failure, the latter reflecting a combination of β-cell dysfunction, dedifferentiation, and apoptosis. Quantification of β-cell apoptosis in diabetes can be challenging both with respect to methodology and selection of clinically relevant inducers and readouts. This protocol describes approaches to measure cell death in immortalized β-cells, primary mouse islet preparations, and pancreatic tissue. The resulting information may be useful for mechanistic studies and assessment of the contribution of β-cell death to pathogenesis. For complete details on the use and execution of this protocol, please refer to McKimpson et al. (2021).
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Affiliation(s)
- Wendy M. McKimpson
- Department of Medicine (Endocrinology), Columbia University, New York, NY 10032, USA,Corresponding author
| | - Richard N. Kitsis
- Departments of Medicine and Cell Biology, Wilf Family Cardiovascular Research Institute, Einstein-Mount Sinai Diabetes Research Center, and Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Liu J, Li X, Wang X, Peng L, Song G, He J. Angiotensin(1-7) Improves Islet Function in Diabetes Through Reducing JNK/Caspase-3 Signaling. Horm Metab Res 2022; 54:250-258. [PMID: 35413746 DOI: 10.1055/a-1796-9286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The aim of this study is to investigate whether Angiotensin (1-7), the physiological antagonist of Angiotensin II (AngII), has antidiabetic activity and the possible mechanism. Male Wistar rats were randomly divided into 3 groups: control group fed the normal diet, DM group fed high-fat diet and injected with STZ, and Angiotensin (1-7) group receiving injection of STZ followed by Angiotensin (1-7) treatment. Serum Ang II, fasting blood glucose, insulin, HOMA-IR, and HOMA-beta were determined in control, diabetes and Angiotensin (1-7) groups. The increased AngII and insulin resistance in diabetes group were accompanied by changes in islet histopathology. However, Angiotensin (1-7) improved the islet function and histopathology in diabetes without affecting the level of AngII. Western blot confirmed that Angiotensin (1-7) decreased the cleaved caspase 3 levels in pancreas of DM. The increased expression of JNK, Bax, and Bcl2 genes under diabetic conditions were partially reversed after Angiotensin (1-7) administration in pancreas. Immunofluorescence analysis showed that p-JNK was markedly increased in islet of DM rats, which was markedly alleviated after Angiotensin (1-7) treatment. Furthermore, Angiotensin (1-7) reversed high glucose(HG) induced mitochondrial apoptosis augments. Finally, Angiotensin (1-7) attenuated the apoptosis of INS-1 cells through reducing JNK activation in diabetes, which was blocked by anisomycin (a potent agonist of JNK). Our findings provide supporting evidence that Angiotensin (1-7) improved the islet beta-cells apoptosis by JNK-mediated mitochondrial dysfunction, which might be a novel target for the treatment and prevention of beta-cells dysfunction in DM.
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Affiliation(s)
- Jing Liu
- Department of Endocrinology, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Xing Li
- Department of Endocrinology, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Xiaoyan Wang
- Department of Endocrinology, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Lina Peng
- Department of Endocrinology, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Guoning Song
- Department of Endocrinology, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Junhua He
- Department of Endocrinology, Second Hospital of Shanxi Medical University, Taiyuan, China
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Liu Y, Huang H, Xu Z, Xue Y, Zhang D, Zhang Y, Li W, Li X. Fucoidan protects pancreas and improves glucose metabolism through inhibiting inflammation and endoplasmic reticulum stress in T2DM rats. Food Funct 2022; 13:2693-2709. [DOI: 10.1039/d1fo04164a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is important to maintain the normal function of pancreas in the prevention and intervention of type 2 diabetes mellitus (T2DM). This study was undertaken to explore the protective effects...
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Sasikumar R, Jyoti Das A, Chandra Deka S. In vitro cytoprotective activity of cyanidin 3-glucoside extracts from Haematocarpus validus pomace on streptozotocin induced oxidative damage in pancreatic β-cells. Saudi J Biol Sci 2021; 28:5338-5348. [PMID: 34466113 PMCID: PMC8381084 DOI: 10.1016/j.sjbs.2021.05.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 05/24/2021] [Accepted: 05/24/2021] [Indexed: 12/02/2022] Open
Abstract
Cyanidin-3-glucoside (C3Ghv) compounds were purified and isolated from the anthocyanins extract of Haematocarpus validus. C3Ghv were studied for antioxidant and cytoprotective properties on pancreatic β-cells of rat insulinoma cells (RINm5F) against the oxidative stress induced by streptozotocin (STZ). The exposure of RINm5F cells to C3Ghv at concentration of 100 and 200 μg/mL for 24 h reduced 10% and 23% cell viability, respectively, as compared to control cells. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) increased the cell viability by 29% as compared to control, on being treated with STZ (10 mM) for 24 h. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) for 24 h followed by exposure to STZ (10 mM) for 1 h decreased the generation of reactive oxygen species (ROS) by 57%, generation of nitric oxide by 22.8%, generation of malondialdehyde (MDA) by 32%, the production of p-ERK ½ by 83%, p-JNK by 82.6%, p-MEK by 57%, and p-p38 MAPK by 64%. The C3Ghv treatment also decreased the ratio of apoptotic proteins Bax to Bcl-2 by 61%, and improved the M2 phase of cell cycle by 75% as compared to STZ treated cells. The overall results suggest that C3Ghv protects pancreatic β-cells against oxidative stress-induced apoptosis, thereby implicating the significant role of C3Ghv as an antidiabetic agent.
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Affiliation(s)
- Raju Sasikumar
- Department of Agribusiness Management and Food Technology, North-Eastern Hill University (NEHU), Tura Campus, West Garo Hills, Tura 794002, Meghalaya, India
| | - Arub Jyoti Das
- Department of Food Engineering and Technology, Tezpur University, Tezpur, Assam, India
| | - Sankar Chandra Deka
- Department of Food Engineering and Technology, Tezpur University, Tezpur, Assam, India
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Gómez-Zorita S, Milton-Laskíbar I, Aguirre L, Fernández-Quintela A, Xiao J, Portillo MP. Effects of Pterostilbene on Diabetes, Liver Steatosis and Serum Lipids. Curr Med Chem 2021; 28:238-252. [PMID: 31663469 DOI: 10.2174/0929867326666191029112626] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/16/2019] [Accepted: 10/27/2019] [Indexed: 02/08/2023]
Abstract
Pterostilbene, a phenolic compound derived from resveratrol, possesses greater bioavailability than its parent compound due to the presence of two methoxyl groups. In this review, the beneficial effects of pterostilbene on diabetes, liver steatosis and dyslipidemia are summarized. Pterostilbene is a useful bioactive compound in preventing type 1 diabetes, insulin resistance and type 2 diabetes in animal models. Concerning type 1 diabetes, the main mechanisms described to justify the positive effects of this phenolic compound are increased liver glycogen content and hepatic glucokinase and phosphofructokinase activities, the recovery of pancreatic islet architecture, cytoprotection and a decrease in serum and pancreatic pro-inflammatory cytokines. As for type 2 diabetes, increased liver glucokinase and glucose-6-phosphatase and decreased fructose-1,6-biphosphatase activities are reported. When insulin resistance is induced by diets, a greater activation of insulin signaling cascade has been reported, increased cardiotrophin-1 levels and liver glucokinase and glucose- 6-phosphatase activities, and a decreased fructose-1,6-biphosphatase activity. Data concerning pterostilbene and liver steatosis are scarce so far, but the reduction in oxidative stress induced by pterostilbene may be involved since oxidative stress is related to the progression of steatosis to steatohepatitis. Finally, pterostilbene effectively reduces total cholesterol, LDL-cholesterol and serum triglyceride levels, while increases HDL-cholesterol in animal models of dyslipidemia.
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Affiliation(s)
- Saioa Gómez-Zorita
- Nutrition and Obesity Group, Department of Pharmacy and Food Sciences, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Institute, Vitoria, Spain
| | - Iñaki Milton-Laskíbar
- Nutrition and Obesity Group, Department of Pharmacy and Food Sciences, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Institute, Vitoria, Spain
| | - Leixuri Aguirre
- Nutrition and Obesity Group, Department of Pharmacy and Food Sciences, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Institute, Vitoria, Spain
| | - Alfredo Fernández-Quintela
- Nutrition and Obesity Group, Department of Pharmacy and Food Sciences, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Institute, Vitoria, Spain
| | - Jianbo Xiao
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Control in Chinese Medicine, University of Macau, Macau SAR, China
| | - María P Portillo
- Nutrition and Obesity Group, Department of Pharmacy and Food Sciences, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Institute, Vitoria, Spain
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Jiang YY, Shui JC, Zhang BX, Chin JW, Yue RS. The Potential Roles of Artemisinin and Its Derivatives in the Treatment of Type 2 Diabetes Mellitus. Front Pharmacol 2020; 11:585487. [PMID: 33381036 PMCID: PMC7768903 DOI: 10.3389/fphar.2020.585487] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a chronic disease that has become a global public health problem. Studies on T2DM prevention and treatment mostly focus on discovering therapeutic drugs. Artemisinin and its derivatives were originally used as antimalarial treatments. In recent years, the roles of artemisinins in T2DM have attracted much attention. Artemisinin treatments not only attenuate insulin resistance and restore islet ß-cell function in T2DM but also have potential therapeutic effects on diabetic complications, including diabetic kidney disease, cognitive impairment, diabetic retinopathy, and diabetic cardiovascular disease. Many in vitro and in vivo experiments have confirmed the therapeutic utility of artemisinin and its derivatives on T2DM, but no article has systematically demonstrated the specific role artemisinin plays in the treatment of T2DM. This review summarizes the potential therapeutic effects and mechanism of artemisinin and its derivatives in T2DM and associated complications, providing a reference for subsequent related research.
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Affiliation(s)
- Ya-Yi Jiang
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jia-Cheng Shui
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Bo-Xun Zhang
- Department of Endocrinology, Guang'anmen Hospital of China, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jia-Wei Chin
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ren-Song Yue
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
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11
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Locatelli CAA, Mulvihill EE. Islet Health, Hormone Secretion, and Insulin Responsivity with Low-Carbohydrate Feeding in Diabetes. Metabolites 2020; 10:E455. [PMID: 33187118 PMCID: PMC7697690 DOI: 10.3390/metabo10110455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/05/2020] [Accepted: 11/07/2020] [Indexed: 12/25/2022] Open
Abstract
Exploring new avenues to control daily fluctuations in glycemia has been a central theme for diabetes research since the Diabetes Control and Complications Trial (DCCT). Carbohydrate restriction has re-emerged as a means to control type 2 diabetes mellitus (T2DM), becoming increasingly popular and supported by national diabetes associations in Canada, Australia, the USA, and Europe. This approval comes from many positive outcomes on HbA1c in human studies; yet mechanisms underlying their success have not been fully elucidated. In this review, we discuss the preclinical and clinical studies investigating the role of carbohydrate restriction and physiological elevations in ketone bodies directly on pancreatic islet health, islet hormone secretion, and insulin sensitivity. Included studies have clearly outlined diet compositions, including a diet with 30% or less of calories from carbohydrates.
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Affiliation(s)
- Cassandra A. A. Locatelli
- Energy Substrate Laboratory, The University of Ottawa Heart Institute, 40 Ruskin Street, H-3229A, Ottawa, ON KIY 4W7, Canada;
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, 451 Smyth Rd, Ottawa, ON K1H 8L1, Canada
| | - Erin E. Mulvihill
- Energy Substrate Laboratory, The University of Ottawa Heart Institute, 40 Ruskin Street, H-3229A, Ottawa, ON KIY 4W7, Canada;
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, 451 Smyth Rd, Ottawa, ON K1H 8L1, Canada
- Montreal Diabetes Research Centre CRCHUM-Pavillion R, 900 Saint-Denis-Room R08.414, Montreal, QC H2X 0A9, Canada
- Centre for Infection, Immunity and Inflammation, The University of Ottawa, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
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12
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Beta Cell Physiological Dynamics and Dysfunctional Transitions in Response to Islet Inflammation in Obesity and Diabetes. Metabolites 2020; 10:metabo10110452. [PMID: 33182622 PMCID: PMC7697558 DOI: 10.3390/metabo10110452] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/02/2020] [Accepted: 10/10/2020] [Indexed: 02/07/2023] Open
Abstract
Beta cells adapt their function to respond to fluctuating glucose concentrations and variable insulin demand. The highly specialized beta cells have well-established endoplasmic reticulum to handle their high metabolic load for insulin biosynthesis and secretion. Beta cell endoplasmic reticulum therefore recognize and remove misfolded proteins thereby limiting their accumulation. Beta cells function optimally when they sense glucose and, in response, biosynthesize and secrete sufficient insulin. Overnutrition drives the pathogenesis of obesity and diabetes, with adverse effects on beta cells. The interleukin signaling system maintains beta cell physiology and plays a role in beta cell inflammation. In pre-diabetes and compromised metabolic states such as obesity, insulin resistance, and glucose intolerance, beta cells biosynthesize and secrete more insulin, i.e., hyperfunction. Obesity is entwined with inflammation, characterized by compensatory hyperinsulinemia, for a defined period, to normalize glycemia. However, with chronic hyperglycemia and diabetes, there is a perpetual high demand for insulin, and beta cells become exhausted resulting in insufficient insulin biosynthesis and secretion, i.e., they hypofunction in response to elevated glycemia. Therefore, beta cell hyperfunction progresses to hypofunction, and may progressively worsen towards failure. Preserving beta cell physiology, through healthy nutrition and lifestyles, and therapies that are aligned with beta cell functional transitions, is key for diabetes prevention and management.
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Bax and Bak jointly control survival and dampen the early unfolded protein response in pancreatic β-cells under glucolipotoxic stress. Sci Rep 2020; 10:10986. [PMID: 32620813 PMCID: PMC7335194 DOI: 10.1038/s41598-020-67755-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 06/12/2020] [Indexed: 12/31/2022] Open
Abstract
ER stress and apoptosis contribute to the loss of pancreatic β-cells under pro-diabetic conditions of glucolipotoxicity. Although activation of canonical intrinsic apoptosis is known to require pro-apoptotic Bcl-2 family proteins Bax and Bak, their individual and combined involvement in glucolipotoxic β-cell death are not known. It has also remained an open question if Bax and Bak in β-cells have non-apoptotic roles in mitochondrial function and ER stress signaling, as suggested in other cell types. Using mice with individual or combined β-cell deletion of Bax and Bak, we demonstrated that glucolipotoxic β-cell death in vitro occurs by both non-apoptotic and apoptotic mechanisms, and the apoptosis could be triggered by either Bax or Bak alone. In contrast, they had non-redundant roles in mediating staurosporine-induced apoptosis. We further established that Bax and Bak do not affect normal glucose-stimulated β-cell Ca2+ responses, insulin secretion, or in vivo glucose tolerance. Finally, our experiments revealed that combined deletion of Bax and Bak amplified the unfolded protein response in islets during the early stages of chemical- or glucolipotoxicity-induced ER stress. These findings shed new light on roles of the core apoptosis machinery in β-cell survival and stress signals of importance for the pathobiology of diabetes.
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14
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Vogel J, Yin J, Su L, Wang SX, Zessis R, Fowler S, Chiu CH, Wilson AC, Chen A, Zecri F, Turner G, Smith TM, DeChristopher B, Xing H, Rothman DM, Cai X, Berdichevsky A. A Phenotypic Screen Identifies Calcium Overload as a Key Mechanism of β-Cell Glucolipotoxicity. Diabetes 2020; 69:1032-1041. [PMID: 32079579 DOI: 10.2337/db19-0813] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 02/07/2020] [Indexed: 11/13/2022]
Abstract
Type 2 diabetes (T2D) is caused by loss of pancreatic β-cell mass and failure of the remaining β-cells to deliver sufficient insulin to meet demand. β-Cell glucolipotoxicity (GLT), which refers to combined, deleterious effects of elevated glucose and fatty acid levels on β-cell function and survival, contributes to T2D-associated β-cell failure. Drugs and mechanisms that protect β-cells from GLT stress could potentially improve metabolic control in patients with T2D. In a phenotypic screen seeking low-molecular-weight compounds that protected β-cells from GLT, we identified compound A that selectively blocked GLT-induced apoptosis in rat insulinoma cells. Compound A and its optimized analogs also improved viability and function in primary rat and human islets under GLT. We discovered that compound A analogs decreased GLT-induced cytosolic calcium influx in islet cells, and all measured β-cell-protective effects correlated with this activity. Further studies revealed that the active compound from this series largely reversed GLT-induced global transcriptional changes. Our results suggest that taming cytosolic calcium overload in pancreatic islets can improve β-cell survival and function under GLT stress and thus could be an effective strategy for T2D treatment.
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Affiliation(s)
| | - Jianning Yin
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Liansheng Su
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Sharon X Wang
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Richard Zessis
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Sena Fowler
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Chun-Hao Chiu
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | | | - Amy Chen
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Frederic Zecri
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Gordon Turner
- Novartis Institutes for BioMedical Research, Cambridge, MA
| | - Thomas M Smith
- Novartis Institutes for BioMedical Research, Cambridge, MA
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15
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Protection from β-cell apoptosis by inhibition of TGF-β/Smad3 signaling. Cell Death Dis 2020; 11:184. [PMID: 32170115 PMCID: PMC7070087 DOI: 10.1038/s41419-020-2365-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 12/18/2022]
Abstract
Prevailing insulin resistance and the resultant hyperglycemia elicits a compensatory response from pancreatic islet beta cells (β-cells) that involves increases in β-cell function and β-cell mass. However, the sustained metabolic stress eventually leads to β-cell failure characterized by severe β-cell dysfunction and progressive loss of β-cell mass. Whereas, β-cell dysfunction is relatively well understood at the mechanistic level, the avenues leading to loss of β-cell mass are less clear with reduced proliferation, dedifferentiation, and apoptosis all potential mechanisms. Butler and colleagues documented increased β-cell apoptosis in pancreas from lean and obese human Type 2 diabetes (T2D) subjects, with no changes in rates of β-cell replication or neogenesis, strongly suggesting a role for apoptosis in β-cell failure. Here, we describe a permissive role for TGF-β/Smad3 in β-cell apoptosis. Human islets undergoing β-cell apoptosis release increased levels of TGF-β1 ligand and phosphorylation levels of TGF-β's chief transcription factor, Smad3, are increased in human T2D islets suggestive of an autocrine role for TGF-β/Smad3 signaling in β-cell apoptosis. Smad3 phosphorylation is similarly increased in diabetic mouse islets undergoing β-cell apoptosis. In mice, β-cell-specific activation of Smad3 promotes apoptosis and loss of β-cell mass in association with β-cell dysfunction, glucose intolerance, and diabetes. In contrast, inactive Smad3 protects from apoptosis and preserves β-cell mass while improving β-cell function and glucose tolerance. At the molecular level, Smad3 associates with Foxo1 to propagate TGF-β-dependent β-cell apoptosis. Indeed, genetic or pharmacologic inhibition of TGF-β/Smad3 signals or knocking down Foxo1 protects from β-cell apoptosis. These findings reveal the importance of TGF-β/Smad3 in promoting β-cell apoptosis and demonstrate the therapeutic potential of TGF-β/Smad3 antagonism to restore β-cell mass lost in diabetes.
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16
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Al-Romaiyan A, Liu B, Persaud S, Jones P. A novel Gymnema sylvestre extract protects pancreatic beta-cells from cytokine-induced apoptosis. Phytother Res 2019; 34:161-172. [PMID: 31515869 DOI: 10.1002/ptr.6512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/04/2019] [Accepted: 08/29/2019] [Indexed: 01/17/2023]
Abstract
Inflammatory cytokines such as interleukin-1β, TNF-α, and interferon-γ are known to be involved in mediating β-cells death in diabetes mellitus (DM). Thus, protecting from β-cells death in patients with DM may be a useful target in alleviating symptoms of hyperglycemia. Traditional plant-based remedies have been used to treat DM for many centuries and may play a role in protecting β-cell from death. An example of these remedies is Gymnema sylvestre (GS) extract. In this study, we investigated the effect of this plant extract on β-cells apoptosis. Om Santal Adivasi (OSA®) maintained cell membrane integrity in MIN6 cells and mouse islets. Om Santal Adivasi significantly protected MIN6 cells and mouse islets from cytokine-induced apoptosis. In the presence of cytokines, OSA® significantly reduced the expression and activity of caspase-3. The antiapoptotic effect of OSA® as shown by microarray analysis is largely mediated by activating pathways involved in cell survival (mainly casein kinase II pathway) and the free radical scavenger system (specifically superoxide dismutase and catalase). This study indicates that the GS isolate OSA® protects against cytokine-induced apoptosis of β-cells by increasing the expression of cell survival pathways and free radical scavenger system.
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Affiliation(s)
- Altaf Al-Romaiyan
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait
| | - Bo Liu
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, London, UK
| | - Shanta Persaud
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, London, UK
| | - Peter Jones
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, London, UK
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17
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Love MR, Sripetchwandee J, Palee S, Chattipakorn SC, Mower MM, Chattipakorn N. Effects of biphasic and monophasic electrical stimulation on mitochondrial dynamics, cell apoptosis, and cell proliferation. J Cell Physiol 2018; 234:816-824. [PMID: 30078226 DOI: 10.1002/jcp.26897] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/13/2018] [Indexed: 12/20/2022]
Abstract
Currently, electrical stimulation (ES) is used to induce changes in various tissues and cellular processes, but its effects on mitochondrial dynamics and mechanisms are unknown. The aim of this study was to compare the effects of monophasic and biphasic, anodal, and cathodal ES on apoptosis, proliferation, and mitochondrial dynamics in neuroblastoma SH-SY5Y cells. Cells were cultured and treated with ES. Alamar blue assay was performed to measure cell proliferation. The proteins expression of apoptotic-related proteins Bcl-2 associated X (Bax), B cell lymphoma 2 (Bcl-2), optic-atrophy-1 (OPA1), mitofusin2 (Mfn2), phosphorylated dynamin-related protein 1 at serine 616 (p-DRP1), and total dynamin-related protein 1 (Total-DRP1) were also determined. The results showed that monophasic anodal and biphasic anodal/cathodal (Bi Anod) ES for 1 hr at 125 pulses per minute (2.0 Hz) produced the most significant increase in cell proliferation. In addition, monophasic anodal and Bi Anod ES treated cells displayed a significant increase in the levels of anti-apoptotic protein Bcl-2, whereas the Bax levels were not changed. Moreover, the levels of Mfn2 were increased in the cells treated by Bi Anod, and OPA1 was increased by monophasic anodal and Bi Anod ES, indicating increased mitochondrial fusion in these ES-treated cells. However, the levels of mitochondrial fission indicated by DRP1 remained unchanged compared with non-stimulated cells. These findings were confirmed through visualization of mitochondria using Mitotracker Deep Red, demonstrating that monophasic anodal and Bi Anod ES could induce pro-survival effects in SH-SY5Y cells through increasing cell proliferation and mitochondrial fusion. Future research is needed to validate these findings for the clinical application of monophasic anodal and Bi Anod ES.
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Affiliation(s)
- Maria R Love
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Faculty of Biological Sciences, The University of Manchester, Manchester, United Kingdom
| | - Jirapas Sripetchwandee
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Siripong Palee
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand.,Department of Oral Biology and Diagnostic Science, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Morton M Mower
- Department of Medicine, University of Colorado, Denver, Colorado
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
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18
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Yuan L, Wang H, Liu Q, Wang Z, Zhang M, Zhao Y, Liang K, Chen L, Xu T, Xu P. Etoposide-induced protein 2.4 functions as a regulator of the calcium ATPase and protects pancreatic β-cell survival. J Biol Chem 2018; 293:10128-10140. [PMID: 29769309 DOI: 10.1074/jbc.ra118.002399] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/07/2018] [Indexed: 12/22/2022] Open
Abstract
Calcium homeostasis is essential for maintaining the viability and function of pancreatic β cells and plays a key role in preventing the development of diabetes. Decreased levels of ATPase sarcoplasmic/endoplasmic reticulum Ca2+-transporting 2 (ATP2a2), the main calcium pump in β cells, are often found in individuals with diabetes and in diabetic animal models. However, the regulators of ATP2a2 and the molecular mechanisms responsible for controlling ATP2a2 activity remain unclear. Etoposide-induced protein 2.4 (Ei24) is also down-regulated in β cells of diabetic individuals, whereas the effect of decreased Ei24 level on β-cell function is not clarified. Here, using Cre-LoxP and CRISPR/Cas9-based genomic knockout (KO) approaches to generate pancreatic β cell-specific Ei24 KO mice and pancreatic β-cell lines, we found that Ei24 regulates ATP2a2 activity. Specifically, we observed that Ei24 binds to ATP2a2 through Ei24 residues 293-299, which we named here the ATP2a2-interacting region (AIR). Loss of Ei24 inactivated ATP2a2, disrupted calcium homeostasis, and deactivated the calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2)-AMP-activated protein kinase (AMPK) pathway. Elevation of calcium concentration in the endoplasmic reticulum or agonist-induced AMPK activation rescued pancreatic β-cell survival and improved glucose tolerance of Ei24 KO mice. Our findings indicate that targeting the Ei24-ATP2a2 interaction to increase ATP2a2 activity can protect pancreatic β cells and improve glucose homeostasis in diabetic models, suggesting that Ei24 could potentially serve as a target to prevent or manage diabetes.
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Affiliation(s)
- Lin Yuan
- From the Key Laboratory of RNA Biology and
| | - Huiyu Wang
- From the Key Laboratory of RNA Biology and.,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100101
| | - Qi Liu
- From the Key Laboratory of RNA Biology and.,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100101
| | - Zhe Wang
- From the Key Laboratory of RNA Biology and.,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100101
| | | | - Yan Zhao
- the National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101
| | - Kuo Liang
- the Department of General Surgery, XuanWu Hospital, Capital Medical University, Beijing 100053, and
| | - Liangyi Chen
- the State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing 100871, China
| | - Tao Xu
- the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100101, .,the National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101
| | - Pingyong Xu
- From the Key Laboratory of RNA Biology and .,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100101
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19
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Antidiabetic and Antiobesity Effects of Artemether in db/db Mice. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8639523. [PMID: 29862294 PMCID: PMC5971258 DOI: 10.1155/2018/8639523] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 03/18/2018] [Indexed: 11/28/2022]
Abstract
This study is designed to investigate the effect of artemether on type 2 diabetic db/db mice. The experiments consisted of three groups: normal control (NC, db/+, 1% methylcellulose, intragastric administration), diabetic control (DM, db/db, 1% methylcellulose, intragastric administration), and artemether treated (artemether, db/db, 200 mg/kg of artemether, intragastric administration). The treatment lasted for two weeks. The food intake, body weight, and fasting blood glucose of mice were measured every three days. At the start and end of the experiment, the intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (IPITT) were performed. We determined the serum insulin and glucagon levels by ELISA kits and calculated insulin resistance index (HOME-IR). HE staining was used to observe the morphologies of pancreas and liver in mice. The damage of pancreatic beta cells was evaluated by TUNEL staining and immunofluorescence. We found the following: (1) compared with the DM group, the food intake and weight increase rate of artemether group significantly reduced (P < 0.05); (2) compared with pretreatment, artemether significantly reduced the fasting blood glucose levels, and the areas under the curves (AUCs) of IPGTT were decreased significantly, increasing the tolerance to glucose of db/db mice. (P < 0.05); (3) artemether improved hyperinsulinemia and decreased the AUCs of IPITT and HOME-IR, increasing the insulin sensitivity of db/db mice. (4) Artemether significantly ameliorated islet vacuolar degeneration and hepatic steatosis in db/db mice. (5) Artemether reduced the apoptosis of pancreatic beta cells and increased insulin secretion in db/db mice compared with DM group (P < 0.05). Our results indicated that artemether significantly improved glucose homeostasis and insulin resistance and had the potential activity to prevent obesity, reduced the severity of fatty liver, and protected pancreatic beta cells, promising to treat type 2 diabetes.
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20
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Hassan FI, Niaz K, Khan F, Maqbool F, Abdollahi M. The relation between rice consumption, arsenic contamination, and prevalence of diabetes in South Asia. EXCLI JOURNAL 2017; 16:1132-1143. [PMID: 29285009 PMCID: PMC5735331 DOI: 10.17179/excli2017-222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Rice is the major staple food for about two billion people living in Asia. It has been reported to contain considerable amount of inorganic arsenic which is toxic to pancreatic beta cells and disrupt glucose homeostasis. Articles and conference papers published between 1992 and 2017, indexed in Scopus, PubMed, EMBASE, Google, and Google scholar were used. Arsenic exposure has been associated with increased blood glucose and insulin levels, or decreased sensitization of insulin cells to glucose uptake. Several studies have shown the association between inorganic arsenic exposure and incidence of diabetes mellitus. Considerable amounts of arsenic have been reported in different types of rice which may be affected by cultivation methods, processing, and country of production. Use of certain microbes, fertilizers, and enzymes may reduce arsenic uptake or accumulation in rice, which may reduce its risk of toxicity. Combined exposure to contaminated rice, other foods and drinking water may increase the risk of diabetes in these countries. Maximum tolerated daily intake of arsenic contaminated rice (2.1 µg/day kg body weight) has been set by WHO, which may be exceeded depending on its content in rice and amount consumed. Hence, increased prevalence of diabetes in South Asia may be related to the consumption of arsenic contaminated rice depending on its content in the rice and daily amount consumed. In this review, we have focused on the possible relation between rice consumption, arsenic contamination, and prevalence of diabetes in South Asia.
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Affiliation(s)
- Fatima Ismail Hassan
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Group, Tehran University of Medical Sciences, Tehran, Iran
- International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Kamal Niaz
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Group, Tehran University of Medical Sciences, Tehran, Iran
- International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Fazlullah Khan
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Group, Tehran University of Medical Sciences, Tehran, Iran
- International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Faheem Maqbool
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Group, Tehran University of Medical Sciences, Tehran, Iran
- International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Abdollahi
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Group, Tehran University of Medical Sciences, Tehran, Iran
- International Campus, Tehran University of Medical Sciences, Tehran, Iran
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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21
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Kumar S, Marriott CE, Alhasawi NF, Bone AJ, Macfarlane WM. The role of tumour suppressor PDCD4 in beta cell death in hypoxia. PLoS One 2017; 12:e0181235. [PMID: 28750063 PMCID: PMC5531437 DOI: 10.1371/journal.pone.0181235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 06/28/2017] [Indexed: 12/31/2022] Open
Abstract
Objective Hypoxia is known to induce pancreatic beta cell dysfunction and apoptosis. Changes in Programmed Cell Death Gene 4 (PDCD4) expression have previously been linked with beta cell neogenesis and function. Our aim was to investigate the effects of hypoxia on cell viability, PDCD4 expression and subcellular localisation. Methods MIN6 beta cells and ARIP ductal cells were exposed to 1% (hypoxia) or 21% O2 (normoxia) for 12 or 24 hours. MTT assay, HPI staining, scanning electron microscopy, western blotting and immunocytochemistry analyses were performed to determine the effect of hypoxia on cell viability, morphology and PDCD4 expression. Results 24 hour exposure to hypoxia resulted in ~70% loss of beta cell viability (P<0.001) compared to normoxia. Both HPI staining and SEM analysis demonstrated beta cell apoptosis and necrosis after 12 hours exposure to hypoxia. ARIP cells also displayed hypoxia-induced apoptosis and altered surface morphology after 24 hours, but no significant growth difference (p>0.05) was observed between hypoxic and normoxic conditions. Significantly higher expression of PDCD4 was observed in both beta cells (P<0.001) and ductal (P<0.01) cells under hypoxic conditions compared to controls. PDCD4 expression was localised to the cytoplasm of both beta cells and ductal cells, with no observed effects of hypoxia, normoxia or serum free conditions on intracellular shuttling of PDCD4. Conclusion These findings indicate that hypoxia-induced expression of PDCD4 is associated with increased beta cell death and suggests that PDCD4 may be an important factor in regulating beta cell survival during hypoxic stress.
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Affiliation(s)
- Sandeep Kumar
- Diabetes Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Claire E. Marriott
- Diabetes Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Nouf F. Alhasawi
- Diabetes Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Adrian J. Bone
- Diabetes Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Wendy M. Macfarlane
- Diabetes Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
- * E-mail:
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22
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Affiliation(s)
- Ting Yuan
- a Centre for Biomolecular Interactions Bremen , University of Bremen , Bremen , Germany
| | - Kathrin Maedler
- a Centre for Biomolecular Interactions Bremen , University of Bremen , Bremen , Germany
| | - Amin Ardestani
- a Centre for Biomolecular Interactions Bremen , University of Bremen , Bremen , Germany
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23
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Schumacher L, Abbott LC. Effects of methyl mercury exposure on pancreatic beta cell development and function. J Appl Toxicol 2016; 37:4-12. [PMID: 27594070 DOI: 10.1002/jat.3381] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/29/2016] [Accepted: 07/31/2016] [Indexed: 12/31/2022]
Abstract
Methyl mercury is an environmental contaminant of worldwide concern. Since the discovery of methyl mercury exposure due to eating contaminated fish as the underlying cause of the Minamata disaster, the scientific community has known about the sensitivity of the developing central nervous system to mercury toxicity. Warnings are given to pregnant women and young children to limit consumption of foods containing methyl mercury to protect the embryonic, fetal and postnatally developing central nervous system. However, evidence also suggests that exposure to methyl mercury or various forms of inorganic mercury may also affect development and function of other organs. Numerous reports indicate a worldwide increase in diabetes, particularly type 2 diabetes. Quite recently, methyl mercury has been shown to have adverse effects on pancreatic beta (β) cell development and function, resulting in insulin resistance and hyperglycemia and may even lead to the development of diabetes. This review discusses possible mechanisms by which methyl mercury exposure may adversely affect pancreatic β cell development and function, and the role that methyl mercury exposure may have in the reported worldwide increase in diabetes, particularly type 2 diabetes. While additional information is needed regarding associations between mercury exposure and specific mechanisms of the pathogenesis of diabetes in the human population, methyl mercury's adverse effects on the body's natural sources of antioxidants suggest that one possible therapeutic strategy could involve supplementation with antioxidants. Thus, it is important that additional investigation be undertaken into the role of methyl mercury exposure and reduced pancreatic β cell function. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Lauren Schumacher
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, TX, 77843-4458, USA
| | - Louise C Abbott
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, TX, 77843-4458, USA
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24
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Nabih ES, Andrawes NG. The Association Between Circulating Levels of miRNA-181a and Pancreatic Beta Cells Dysfunction via SMAD7 in Type 1 Diabetic Children and Adolescents. J Clin Lab Anal 2016; 30:727-31. [PMID: 26892629 PMCID: PMC6807027 DOI: 10.1002/jcla.21928] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 12/08/2015] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND miRNA-181a has been implicated in autoimmunity and apoptosis. Therefore, this study was conducted to explore its possible role in pancreatic beta-cells dysfunction. METHODS miRNA-181a expression was evaluated by real-time PCR in serum of 40 type 1 diabetic children and adolescents and 40 age- and gender-matched healthy controls. RESULTS miRNA-181a expression was significantly higher in diabetic children and adolescents and it was negatively correlated to fasting C-peptide and SMAD7 levels. CONCLUSION miRNA-181a appears to play a potential role in pancreatic beta-cells dysfunction via SMAD7.
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Affiliation(s)
- Enas Samir Nabih
- Department of Medical Biochemistry, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
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25
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Tennant BR, Vanderkruk B, Dhillon J, Dai D, Verchere CB, Hoffman BG. Myt3 suppression sensitizes islet cells to high glucose-induced cell death via Bim induction. Cell Death Dis 2016; 7:e2233. [PMID: 27195679 PMCID: PMC4917670 DOI: 10.1038/cddis.2016.141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/11/2016] [Accepted: 04/22/2016] [Indexed: 12/13/2022]
Abstract
Diabetes is a chronic disease that results from the body's inability to properly control circulating blood glucose levels. The loss of glucose homoeostasis can arise from a loss of β-cell mass because of immune-cell-mediated attack, as in type 1 diabetes, and/or from dysfunction of individual β-cells (in conjunction with target organ insulin resistance), as in type 2 diabetes. A better understanding of the transcriptional pathways regulating islet-cell survival is of great importance for the development of therapeutic strategies that target β-cells for diabetes. To this end, we previously identified the transcription factor Myt3 as a pro-survival factor in islets following acute suppression of Myt3 in vitro. To determine the effects of Myt3 suppression on islet-cell survival in vivo, we used an adenovirus to express an shRNA targeting Myt3 in syngeneic optimal and marginal mass islet transplants, and demonstrate that suppression of Myt3 impairs the function of marginal mass grafts. Analysis of grafts 5 weeks post-transplant revealed that grafts transduced with the shMyt3 adenovirus contained ~20% the number of transduced cells as grafts transduced with a control adenovirus. In fact, increased apoptosis and significant cell loss in the shMyt3-transduced grafts was evident after only 5 days, suggesting that Myt3 suppression sensitizes islet cells to stresses present in the early post-transplant period. Specifically, we find that Myt3 suppression sensitizes islet cells to high glucose-induced cell death via upregulation of the pro-apoptotic Bcl2 family member Bim. Taken together these data suggest that Myt3 may be an important link between glucotoxic and immune signalling pathways.
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Affiliation(s)
- B R Tennant
- Child and Family Research Institute, British Columbia Children's Hospital, 950 W28th Avenue, Vancouver, British Columbia, Canada V5Z 4H4
| | - B Vanderkruk
- Child and Family Research Institute, British Columbia Children's Hospital, 950 W28th Avenue, Vancouver, British Columbia, Canada V5Z 4H4
| | - J Dhillon
- Child and Family Research Institute, British Columbia Children's Hospital, 950 W28th Avenue, Vancouver, British Columbia, Canada V5Z 4H4
| | - D Dai
- Child and Family Research Institute, British Columbia Children's Hospital, 950 W28th Avenue, Vancouver, British Columbia, Canada V5Z 4H4
| | - C B Verchere
- Child and Family Research Institute, British Columbia Children's Hospital, 950 W28th Avenue, Vancouver, British Columbia, Canada V5Z 4H4.,Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4E3.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada V6T 2B5
| | - B G Hoffman
- Child and Family Research Institute, British Columbia Children's Hospital, 950 W28th Avenue, Vancouver, British Columbia, Canada V5Z 4H4.,Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4E3
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Hormetic and regulatory effects of lipid peroxidation mediators in pancreatic beta cells. Mol Aspects Med 2016; 49:49-77. [PMID: 27012748 DOI: 10.1016/j.mam.2016.03.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 02/23/2016] [Accepted: 03/09/2016] [Indexed: 12/12/2022]
Abstract
Nutrient sensing mechanisms of carbohydrates, amino acids and lipids operate distinct pathways that are essential for the adaptation to varying metabolic conditions. The role of nutrient-induced biosynthesis of hormones is paramount for attaining metabolic homeostasis in the organism. Nutrient overload attenuate key metabolic cellular functions and interfere with hormonal-regulated inter- and intra-organ communication, which may ultimately lead to metabolic derangements. Hyperglycemia and high levels of saturated free fatty acids induce excessive production of oxygen free radicals in tissues and cells. This phenomenon, which is accentuated in both type-1 and type-2 diabetic patients, has been associated with the development of impaired glucose tolerance and the etiology of peripheral complications. However, low levels of the same free radicals also induce hormetic responses that protect cells against deleterious effects of the same radicals. Of interest is the role of hydroxyl radicals in initiating peroxidation of polyunsaturated fatty acids (PUFA) and generation of α,β-unsaturated reactive 4-hydroxyalkenals that avidly form covalent adducts with nucleophilic moieties in proteins, phospholipids and nucleic acids. Numerous studies have linked the lipid peroxidation product 4-hydroxy-2E-nonenal (4-HNE) to different pathological and cytotoxic processes. Similarly, two other members of the family, 4-hydroxyl-2E-hexenal (4-HHE) and 4-hydroxy-2E,6Z-dodecadienal (4-HDDE), have also been identified as potential cytotoxic agents. It has been suggested that 4-HNE-induced modifications in macromolecules in cells may alter their cellular functions and modify signaling properties. Yet, it has also been acknowledged that these bioactive aldehydes also function as signaling molecules that directly modify cell functions in a hormetic fashion to enable cells adapt to various stressful stimuli. Recent studies have shown that 4-HNE and 4-HDDE, which activate peroxisome proliferator-activated receptor δ (PPARδ) in vascular endothelial cells and insulin secreting beta cells, promote such adaptive responses to ameliorate detrimental effects of high glucose and diabetes-like conditions. In addition, due to the electrophilic nature of these reactive aldehydes they form covalent adducts with electronegative moieties in proteins, phosphatidylethanolamine and nucleotides. Normally these non-enzymatic modifications are maintained below the cytotoxic range due to efficient cellular neutralization processes of 4-hydroxyalkenals. The major neutralizing enzymes include fatty aldehyde dehydrogenase (FALDH), aldose reductase (AR) and alcohol dehydrogenase (ADH), which transform the aldehyde to the corresponding carboxylic acid or alcohols, respectively, or by biding to the thiol group in glutathione (GSH) by the action of glutathione-S-transferase (GST). This review describes the hormetic and cytotoxic roles of oxygen free radicals and 4-hydroxyalkenals in beta cells exposed to nutritional challenges and the cellular mechanisms they employ to maintain their level at functional range below the cytotoxic threshold.
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Wills QF, Boothe T, Asadi A, Ao Z, Warnock GL, Kieffer TJ, Johnson JD. Statistical approaches and software for clustering islet cell functional heterogeneity. Islets 2016; 8:48-56. [PMID: 26909740 PMCID: PMC4878268 DOI: 10.1080/19382014.2016.1150664] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Worldwide efforts are underway to replace or repair lost or dysfunctional pancreatic β-cells to cure diabetes. However, it is unclear what the final product of these efforts should be, as β-cells are thought to be heterogeneous. To enable the analysis of β-cell heterogeneity in an unbiased and quantitative way, we developed model-free and model-based statistical clustering approaches, and created new software called TraceCluster. Using an example data set, we illustrate the utility of these approaches by clustering dynamic intracellular Ca(2+) responses to high glucose in ∼300 simultaneously imaged single islet cells. Using feature extraction from the Ca(2+) traces on this reference data set, we identified 2 distinct populations of cells with β-like responses to glucose. To the best of our knowledge, this report represents the first unbiased cluster-based analysis of human β-cell functional heterogeneity of simultaneous recordings. We hope that the approaches and tools described here will be helpful for those studying heterogeneity in primary islet cells, as well as excitable cells derived from embryonic stem cells or induced pluripotent cells.
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Affiliation(s)
- Quin F Wills
- a Wellcome Trust Center for Human Genetics, University of Oxford , Oxford , United Kingdom
- b Weatherall Institute of Molecular Medicine, University of Oxford , Oxford , United Kingdom
| | - Tobias Boothe
- c Department of Cellular and Physiological Sciences , Life Sciences Center, University of British Columbia , Vancouver , Canada
| | - Ali Asadi
- c Department of Cellular and Physiological Sciences , Life Sciences Center, University of British Columbia , Vancouver , Canada
| | - Ziliang Ao
- d Department of Surgery , University of British Columbia , Vancouver , Canada
| | - Garth L Warnock
- d Department of Surgery , University of British Columbia , Vancouver , Canada
| | - Timothy J Kieffer
- c Department of Cellular and Physiological Sciences , Life Sciences Center, University of British Columbia , Vancouver , Canada
- d Department of Surgery , University of British Columbia , Vancouver , Canada
| | - James D Johnson
- c Department of Cellular and Physiological Sciences , Life Sciences Center, University of British Columbia , Vancouver , Canada
- d Department of Surgery , University of British Columbia , Vancouver , Canada
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Li FF, Chen BJ, Li W, Li L, Zha M, Zhou S, Bachem MG, Sun ZL. Islet Stellate Cells Isolated from Fibrotic Islet of Goto-Kakizaki Rats Affect Biological Behavior of Beta-Cell. J Diabetes Res 2016; 2016:6924593. [PMID: 26697502 PMCID: PMC4678093 DOI: 10.1155/2016/6924593] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/18/2015] [Accepted: 06/22/2015] [Indexed: 12/30/2022] Open
Abstract
We previously isolated islet stellate cells (ISCs) from healthy Wistar rat islets. In the present study, we isolated "already primed by diabetic environment" ISCs from islets of Goto-Kakizaki rats, determined the gene profile of these cells, and assessed the effects of these ISCs on beta-cell function and survival. We detected gene expression of ISCs by digital gene expression. INS-1 cell proliferation, apoptosis, and insulin production were measured after being treated with ISCs supernatant (SN). We observed the similar expression pattern of ISCs and PSCs, but 1067 differentially expressed genes. Insulin production in INS-1 cells cultured with ISC-SN was significantly reduced. The 5-ethynyl-2'-deoxyuridine-positive INS-1 cells treated with ISC-SN were decreased. Propidium iodide- (PI-) positive INS-1 cells were 2.6-fold higher than those in control groups. Caspase-3 activity was increased. In conclusion, ISCs presented in fibrotic islet of GK rats might be special PSCs, which impaired beta-cell function and proliferation and increased beta-cell apoptosis.
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Affiliation(s)
- Feng-Fei Li
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
- Department of Endocrinology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210012, China
| | - Bi-Jun Chen
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
| | - Wei Li
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
| | - Ling Li
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
| | - Min Zha
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
| | - S. Zhou
- Department of Clinical Chemistry, University Hospital Ulm, 89081 Ulm, Germany
| | - M. G. Bachem
- Department of Clinical Chemistry, University Hospital Ulm, 89081 Ulm, Germany
| | - Zi-Lin Sun
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
- *Zi-Lin Sun:
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Szabat M, Modi H, Ramracheya R, Girbinger V, Chan F, Lee JTC, Piske M, Kamal S, Carol Yang YH, Welling A, Rorsman P, Johnson JD. High-content screening identifies a role for Na(+) channels in insulin production. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150306. [PMID: 27019722 PMCID: PMC4807443 DOI: 10.1098/rsos.150306] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Abstract
Insulin production is the central feature of functionally mature and differentiated pancreatic β-cells. Reduced insulin transcription and dedifferentiation have been implicated in type 2 diabetes, making drugs that could reverse these processes potentially useful. We have previously established ratiometric live-cell imaging tools to identify factors that increase insulin promoter activity and promote β-cell differentiation. Here, we present a single vector imaging tool with eGFP and mRFP, driven by the Pdx1 and Ins1 promoters, respectively, targeted to the nucleus to enhance identification of individual cells in a high-throughput manner. Using this new approach, we screened 1120 off-patent drugs for factors that regulate Ins1 and Pdx1 promoter activity in MIN6 β-cells. We identified a number of compounds that positively modulate Ins1 promoter activity, including several drugs known to modulate ion channels. Carbamazepine was selected for extended follow-up, as our previous screen also identified this use-dependent sodium channel inhibitor as a positive modulator of β-cell survival. Indeed, carbamazepine increased Ins1 and Ins2 mRNA in primary mouse islets at lower doses than were required to protect β-cells. We validated the role of sodium channels in insulin production by examining Nav1.7 (Scn9a) knockout mice and remarkably islets from these animals had dramatically elevated insulin content relative to wild-type controls. Collectively, our experiments provide a starting point for additional studies aimed to identify drugs and molecular pathways that control insulin production and β-cell differentiation status. In particular, our unbiased screen identified a novel role for a β-cell sodium channel gene in insulin production.
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Affiliation(s)
- Marta Szabat
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Honey Modi
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Reshma Ramracheya
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Headington OX3 7LE, UK
| | - Vroni Girbinger
- Institut für Pharmakologie und Toxikologie der Technischen Universität, 80802 München, Germany
| | - Forson Chan
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Jason T. C. Lee
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Micah Piske
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Sepehr Kamal
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Yu Hsuan Carol Yang
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Andrea Welling
- Institut für Pharmakologie und Toxikologie der Technischen Universität, 80802 München, Germany
| | - Patrik Rorsman
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Headington OX3 7LE, UK
| | - James D. Johnson
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
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Yang YHC, Wills QF, Johnson JD. A live-cell, high-content imaging survey of 206 endogenous factors across five stress conditions reveals context-dependent survival effects in mouse primary beta cells. Diabetologia 2015; 58:1239-49. [PMID: 25773404 PMCID: PMC4415993 DOI: 10.1007/s00125-015-3552-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/10/2015] [Indexed: 12/22/2022]
Abstract
AIMS/HYPOTHESIS Beta cell death is a hallmark of diabetes. It is not known whether specific cellular stresses associated with type 1 or type 2 diabetes require specific factors to protect pancreatic beta cells. No systematic comparison of endogenous soluble factors in the context of multiple pro-apoptotic conditions has been published. METHODS Primary mouse islet cells were cultured in conditions mimicking five type 1 or type 2 diabetes-related stresses: basal 5 mmol/l glucose, cytokine cocktail (25 ng/ml TNF-α, 10 ng/ml IL-1β, 10 ng/ml IFN-γ), 1 μmol/l thapsigargin, 1.5 mmol/l palmitate and 20 mmol/l glucose (all in the absence of serum). We surveyed the effects of a library of 206 endogenous factors (selected based on islet expression of their receptors) on islet cell survival through multi-parameter, live-cell imaging. RESULTS Our survey pointed to survival factors exhibiting generalised protective effects across conditions meant to model different types of diabetes and stages of the diseases. For example, our survey and follow-up experiments suggested that OLFM1 is a novel protective factor for mouse and human beta cells across multiple conditions. Most strikingly, we also found specific protective survival factors for each model stress condition. For example, semaphorin4A (SEMA4A) was toxic to islet cells in the serum-free baseline and serum-free 20 mmol/l glucose conditions, but protective in the context of lipotoxicity. Rank product testing supported the consistency of our observations. CONCLUSIONS/INTERPRETATION Collectively, our survey reveals previously unidentified islet cell survival factors and suggest their potential utility in individualised medicine.
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Affiliation(s)
- Yu Hsuan Carol Yang
- Department of Cellular and Physiological Sciences, Faculty of Medicine, Diabetes Research Group, Life Sciences Institute, University of British Columbia, 5358-2350 Health Sciences Mall, Vancouver, BC Canada V6T 1Z3
| | - Quin F. Wills
- Wellcome Trust Centre for Human Genetics, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - James D. Johnson
- Department of Cellular and Physiological Sciences, Faculty of Medicine, Diabetes Research Group, Life Sciences Institute, University of British Columbia, 5358-2350 Health Sciences Mall, Vancouver, BC Canada V6T 1Z3
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Keoni CL, Brown TL. Inhibition of Apoptosis and Efficacy of Pan Caspase Inhibitor, Q-VD-OPh, in Models of Human Disease. J Cell Death 2015; 8:1-7. [PMID: 25922583 PMCID: PMC4395138 DOI: 10.4137/jcd.s23844] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/08/2015] [Accepted: 03/10/2015] [Indexed: 12/25/2022] Open
Abstract
Apoptosis is physiological cell death required for the cellular maintenance of homeostasis, and caspases play a major role in the execution of this process. Numerous disorders occur when levels of apoptosis within an organism are excessive, and several studies have explored the possibility of using caspase inhibitors to prevent these disorders. Q-VD-OPh (quinolyl-valyl-O-methylaspartyl-[2,6-difluorophenoxy]-methyl ketone), a novel pan caspase inhibitor, has been used because of its efficacy to inhibit apoptosis at low concentrations, its ability to cross the blood-brain barrier, as well as being nontoxic in vivo. This review examines Q-VD-OPh's ability to inhibit apoptosis in several animal models of human disease.
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Affiliation(s)
- Chanel Li Keoni
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Thomas L Brown
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
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Xu L, Yang F, Wang J, Huang H, Huang Y. Anti-diabetic effect mediated by Ramulus mori polysaccharides. Carbohydr Polym 2015; 117:63-69. [DOI: 10.1016/j.carbpol.2014.09.052] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 11/28/2022]
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Albrecht T, Zhao Y, Nguyen TH, Campbell RE, Johnson JD. Fluorescent biosensors illuminate calcium levels within defined beta-cell endosome subpopulations. Cell Calcium 2015; 57:263-74. [PMID: 25682167 DOI: 10.1016/j.ceca.2015.01.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/26/2014] [Accepted: 01/19/2015] [Indexed: 11/18/2022]
Abstract
Live cell imaging has revealed that calcium ions (Ca(2+)) pass in and out of many cellular organelles. However, technical hurdles have limited measurements of Ca(2+) in acidic organelles, such as endosomes. Although evidence hints that endosomes play a role in Ca(2+) signaling, direct measurements within endosomal lumina represent one of the final frontiers in organelle imaging. To measure Ca(2+) in a TiVAMP-positive endosome sub-population, the pH-resistant ratiometric Ca(2+) biosensor GEM-GECO1 and the ratiometric pH biosensor mKeima were used. A positive correlation between acidic endosomal pH and higher Ca(2+) was observed within these Rab5a- and Rab7-positive compartments. Ca(2+) concentration in most endosomes was estimated to be below 2μM, lower than Ca(2+) levels in several other intracellular stores, indicating that endosomes may take up Ca(2+) during physiological stimulation. Indeed, endosomes accumulated Ca(2+) during glucose-stimulation, a condition where endosomal pH did not change. Our biosensors permitted the first measurements revealing a role for endosomes in cellular Ca(2+) homeostasis during physiological stimulation.
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Affiliation(s)
- Tobias Albrecht
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Yongxin Zhao
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Trang Hai Nguyen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - James D Johnson
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.
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Jabir NR, Firoz CK, Baeesa SS, Ashraf GM, Akhtar S, Kamal W, Kamal MA, Tabrez S. Synopsis on the linkage of Alzheimer's and Parkinson's disease with chronic diseases. CNS Neurosci Ther 2014; 21:1-7. [PMID: 25399848 DOI: 10.1111/cns.12344] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 12/12/2022] Open
Abstract
Neurodegeneration is the progressive loss of neuronal structure and function, which ultimately leads to neurological disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis, and Huntington's disease. Even after the recent significant advances in neurobiology, the above-mentioned disorders continue to haunt the global population. Several studies have suggested the role of specific environmental and genetic risk factors associated with these disorders. However, the exact mechanism associated with the progression of these disorders still needs to be elucidated. In the recent years, sophisticated research has revealed interesting association of prominent neurodegenerative disorders such as AD and PD with chronic diseases such as cancer, diabetes, and cardiovascular diseases. Several common molecular mechanisms such as generation of free radicals, oxidative DNA damage, aberrations in mitochondrial DNA, and dysregulation of apoptosis have been highlighted as possible points of connection. The present review summarizes the possible mechanism of coexistence of AD and PD with other chronic diseases.
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Affiliation(s)
- Nasimudeen R Jabir
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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Bhakkiyalakshmi E, Sireesh D, Rajaguru P, Paulmurugan R, Ramkumar KM. The emerging role of redox-sensitive Nrf2-Keap1 pathway in diabetes. Pharmacol Res 2014; 91:104-14. [PMID: 25447793 DOI: 10.1016/j.phrs.2014.10.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/08/2014] [Accepted: 10/16/2014] [Indexed: 12/30/2022]
Abstract
The pathogenic processes involving in the development of diabetes range from autoimmune destruction of pancreatic β-cells with consequent insulin deficiency to abnormalities that result in resistance to insulin action. The major contributing factor for excessive β-cell death includes oxidative stress-mediated mitochondrial damage, which creates an imbalance in redox homeostasis. Yet, β-cells have evolved adaptive mechanisms to endure a wide range of stress conditions to safeguard its potential functions. These include 'Nrf2/Keap1' pathway, a key cellular defense mechanism, to combat oxidative stress by regulating phase II detoxifying and antioxidant genes. During diabetes, redox imbalance provokes defective Nrf2-dependent signaling and compromise antioxidant capacity of the pancreas which turnout β-cells to become highly vulnerable against various insults. Hence, identification of small molecule activators of Nrf2/Keap1 pathway remains significant to enhance cellular defense to overcome the burden of oxidative stress related disturbances. This review summarizes the molecular mechanism behind Nrf2 activation and the impact of Nrf2 activators in diabetes and its complications.
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Affiliation(s)
| | - Dornadula Sireesh
- SRM Research Institute, SRM University, Kattankulathur 603 203, Tamilnadu, India
| | - Palanisamy Rajaguru
- Department of Biotechnology, Anna University-BIT Campus, Tiruchirappalli 620 024, Tamilnadu, India
| | - Ramasamy Paulmurugan
- Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
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Fernández MS. Human IAPP amyloidogenic properties and pancreatic β-cell death. Cell Calcium 2014; 56:416-27. [PMID: 25224501 DOI: 10.1016/j.ceca.2014.08.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/09/2014] [Accepted: 08/20/2014] [Indexed: 02/07/2023]
Abstract
A hallmark of type 2 diabetes mellitus (T2DM) is the presence of extracellular amyloid deposits in the islets of Langerhans. These deposits are formed by the human islet amyloid polypeptide, hIAPP (or amylin), which is a hormone costored and cosecreted with insulin. Under normal conditions, the hormone remains in solution but, in the pancreas of T2DM individuals, it undergoes misfolding giving rise to oligomers and cross-β amyloid fibrils. Accumulating evidence suggests that the amyloid deposits that accompany type 2 diabetes mellitus are not just a trivial epiphenomenon derived from the disease progression. Rather, hIAPP aggregation induces processes that impair the functionality and viability of β-cells and may lead to apoptosis. The present review article aims to summarize a few aspects of the current knowledge of this amyloidogenic polypeptide. In the first place, the physicochemical properties which condition its propensity to misfold and form aggregates. Secondly, how these properties confer hIAPP the capacity to interfere with some signaling of the pancreatic β-cell, interact with membranes, form channels or affect natural ion channels, including calcium channels. Finally, how misfolded hIAPP cytotoxicity results in apoptosis. A number of pathophysiological changes of the T2DM islet can be related to the amyloidogenic properties of hIAPP. However, in a certain way, the in vivo aggregation of the polypeptide also reflects a failure of chaperones and, in general, of cellular proteostasis, supporting the view that T2DM may also be considered as a conformational disorder.
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Affiliation(s)
- Marta S Fernández
- Department of Biochemistry, Centro de Investigación y de Estudios Avanzados del I.P.N. (CINVESTAV), Ave, Politécnico 2508, PO Box 14-740, 07000 México D.F., Mexico.
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Skovsø S. Modeling type 2 diabetes in rats using high fat diet and streptozotocin. J Diabetes Investig 2014; 5:349-58. [PMID: 25411593 PMCID: PMC4210077 DOI: 10.1111/jdi.12235] [Citation(s) in RCA: 365] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/07/2014] [Accepted: 03/14/2014] [Indexed: 12/21/2022] Open
Abstract
The pathology of type 2 diabetes is complex, with multiple stages culminating in a functional β‐cell mass that is insufficient to meet the body's needs. Although the broad outlines of the disease etiology are known, many critical questions remain to be answered before next‐generation therapeutics can be developed. In order to further elucidate the pathobiology of this disease, animal models mimicking the pathology of human type 2 diabetes are of great value. One example of a type 2 diabetes animal model is the high‐fat diet‐fed, streptozotocin (HFD/STZ)‐treated rat model. The present review first summarizes the current understanding of the metabolic profile and pathology involved in the different stages of the type 2 diabetes disease progression in humans. Second, the known characteristics of the HFD/STZ rat model are reviewed and compared with the pathophysiology of human type 2 diabetes. Next, the suitability of the HFD/STZ model as a model of type 2 diabetes with a focus on identifying critical caveats and unanswered questions about the model is discussed. The improved understanding of refined animal models will hopefully lead to more relevant preclinical studies and development of improved therapeutics for diabetes. Depending on the amount of residual functional β‐cells mass, the HFD/STZ rat model might be a suitable animal model of the final stage of type 2 diabetes.
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Affiliation(s)
- Søs Skovsø
- In vivo Pharmacology Graduate Program Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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Glaucoma – Diabetes of the brain: A radical hypothesis about its nature and pathogenesis. Med Hypotheses 2014; 82:535-46. [DOI: 10.1016/j.mehy.2014.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 01/27/2014] [Accepted: 02/03/2014] [Indexed: 12/12/2022]
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Nojiri T, Kurano M, Tokuhara Y, Ohkubo S, Hara M, Ikeda H, Tsukamoto K, Yatomi Y. Modulation of sphingosine-1-phosphate and apolipoprotein M levels in the plasma, liver and kidneys in streptozotocin-induced diabetic mice. J Diabetes Investig 2014; 5:639-48. [PMID: 25422763 PMCID: PMC4234226 DOI: 10.1111/jdi.12232] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/24/2014] [Accepted: 03/16/2014] [Indexed: 12/19/2022] Open
Abstract
AIMS/INTRODUCTION Sphingosine-1-phosphate (S1P), a multifunctional bioactive lipid mediator, is involved in various diseases. Apolipoprotein M (ApoM) carries S1P on high-density lipoprotein and modulates S1P metabolism to increase the total S1P mass in the body. Both S1P and ApoM are involved in diabetes. MATERIALS AND METHODS The present study examined the modulation of S1P and ApoM levels in the plasma, liver and kidneys in streptozotocin-induced diabetes (STZ) mice, and the effects of insulin on the S1P and ApoM levels in the plasma and liver in STZ mice and normal mice. We also examined the effects of insulin and glucose on the ApoM levels in HepG2 cells. RESULTS In STZ mice, both the plasma S1P and ApoM levels were higher than those in control mice. The hepatic S1P and ApoM contents were also elevated. The hepatic S1P and ApoM contents were reduced by insulin treatment, whereas high-dose insulin decreased the plasma S1P and ApoM levels. In mice without streptozotocin treatment, the administration of insulin decreased the plasma S1P and ApoM levels, and the hepatic content of ApoM, whereas the hepatic level of S1P was not altered. Treatment with insulin and incubation under a low glucose level decreased the ApoM levels in HepG2 cells. Regarding the kidney, the renal levels of S1P and ApoM were increased in STZ mice, and insulin treatment partially restored this increment. CONCLUSIONS In STZ mice, the levels of S1P and ApoM in the plasma, liver, and kidneys were increased. Insulin treatment somehow reversed this modulation in STZ mice.
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Affiliation(s)
- Takahiro Nojiri
- Department of Clinical Laboratory, The University of Tokyo Hospital Tokyo, Japan
| | - Makoto Kurano
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo Tokyo, Japan
| | - Yasunori Tokuhara
- Department of Clinical Laboratory, The University of Tokyo Hospital Tokyo, Japan ; The Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University Osaka, Japan
| | - Shigeo Ohkubo
- Department of Clinical Laboratory, The University of Tokyo Hospital Tokyo, Japan
| | - Masumi Hara
- Department of Medicine IV, Mizonokuchi Hospital, Teikyo University School of Medicine Kawasaki, Japan
| | - Hitoshi Ikeda
- Department of Clinical Laboratory, The University of Tokyo Hospital Tokyo, Japan ; Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo Tokyo, Japan
| | - Kazuhisa Tsukamoto
- Department of Metabolism, Diabetes and Nephrology, Aizu Medical Center, Fukushima Medical University Fukushima, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory, The University of Tokyo Hospital Tokyo, Japan ; Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo Tokyo, Japan
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Xue M, Jackson CJ. Activated protein C and its potential applications in prevention of islet β-cell damage and diabetes. VITAMINS AND HORMONES 2014; 95:323-63. [PMID: 24559924 DOI: 10.1016/b978-0-12-800174-5.00013-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Activated protein C (APC) is derived from its precursor, protein C (PC). Originally thought to be synthesized exclusively by the liver, recent reports have shown that PC is also produced by many other cells including pancreatic islet β cells. APC functions as a physiological anticoagulant with anti-inflammatory, anti-apoptotic, and barrier-stabilizing properties. APC exerts its protective effects via an intriguing mechanism requiring combinations of endothelial PC receptor, protease-activated receptors, epidermal growth factor receptor, Tie2 or CD11b, depending on cell types. Diabetes is a chronic condition resulted from the body's inability to produce and/or properly use insulin. The prevalence of diabetes has risen dramatically and has become one of the major causes of premature mortality and morbidity worldwide. Diabetes prevention is an ideal approach to reduce this burden. Type 1 and type 2 diabetes are the major forms of diabetes mellitus, and both are characterized by an autoimmune response, intraislet inflammation, β-cell apoptosis, and progressive β-cell loss. Protecting β-cell from damage is critical in both prevention and treatment of diabetes. Recent in vitro and animal studies show that APC's strong anti-inflammatory and anti-apoptotic properties are beneficial in preventing β-cell destruction and diabetes in the NOD mouse model of type 1 diabetes. Future preventive and therapeutic uses of APC in diabetes look very promising.
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Affiliation(s)
- Meilang Xue
- Sutton Arthritis Research Laboratories, Kolling Institute of Medical Research, The University of Sydney at Royal North Shore Hospital, St Leonards, New South Wales, Australia.
| | - Christopher J Jackson
- Sutton Arthritis Research Laboratories, Kolling Institute of Medical Research, The University of Sydney at Royal North Shore Hospital, St Leonards, New South Wales, Australia
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Actin is a target of T-cell reactivity in patients with advanced carotid atherosclerotic plaques. Mediators Inflamm 2013; 2013:261054. [PMID: 24324294 PMCID: PMC3844233 DOI: 10.1155/2013/261054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/07/2013] [Indexed: 12/04/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory disease of the arterial wall associated with autoimmune reactions. In a previous study, we observed the presence of actin-specific antibodies in sera from patients with carotid atherosclerosis. To extend our previous results we evaluated the possible role of actin as antigenic target of cell-mediated immune reactions in carotid atherosclerosis. Peripheral blood mononuclear cells (PBMC) from 17 patients and 16 healthy subjects were tested by cell proliferation assay and by ELISA for cytokine production. Actin induced a proliferative response in 47% of patients' PBMC samples, with SI ranging from 2.6 to 21.1, and in none of the healthy subjects' samples (patients versus healthy subjects, P = 0.02). The presence of diabetes in patients was significantly associated with proliferative response to actin (P = 0.04). IFN-γ and TNF-α concentrations were higher in PBMC from patients than in those from healthy subjects and in PBMC proliferating to actin than in nonproliferating ones. Our data demonstrate for the first time a role of actin as a target autoantigen of cellular immune reactions in patients with carotid atherosclerosis. The preferential proinflammatory Th1 activation suggests that actin could contribute to endothelial dysfunction, tissue damage, and systemic inflammation in carotid atherosclerosis.
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Krautkramer KA, Linnemann AK, Fontaine DA, Whillock AL, Harris TW, Schleis GJ, Truchan NA, Marty-Santos L, Lavine JA, Cleaver O, Kimple ME, Davis DB. Tcf19 is a novel islet factor necessary for proliferation and survival in the INS-1 β-cell line. Am J Physiol Endocrinol Metab 2013; 305:E600-10. [PMID: 23860123 PMCID: PMC3761170 DOI: 10.1152/ajpendo.00147.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recently, a novel type 1 diabetes association locus was identified at human chromosome 6p31.3, and transcription factor 19 (TCF19) is a likely causal gene. Little is known about Tcf19, and we now show that it plays a role in both proliferation and apoptosis in insulinoma cells. Tcf19 is expressed in mouse and human islets, with increasing mRNA expression in nondiabetic obesity. The expression of Tcf19 is correlated with β-cell mass expansion, suggesting that it may be a transcriptional regulator of β-cell mass. Increasing proliferation and decreasing apoptotic cell death are two strategies to increase pancreatic β-cell mass and prevent or delay diabetes. siRNA-mediated knockdown of Tcf19 in the INS-1 insulinoma cell line, a β-cell model, results in a decrease in proliferation and an increase in apoptosis. There was a significant reduction in the expression of numerous cell cycle genes from the late G1 phase through the M phase, and cells were arrested at the G1/S checkpoint. We also observed increased apoptosis and susceptibility to endoplasmic reticulum (ER) stress after Tcf19 knockdown. There was a reduction in expression of genes important for the maintenance of ER homeostasis (Bip, p58(IPK), Edem1, and calreticulin) and an increase in proapoptotic genes (Bim, Bid, Nix, Gadd34, and Pdia2). Therefore, Tcf19 is necessary for both proliferation and survival and is a novel regulator of these pathways.
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Affiliation(s)
- Kimberly A Krautkramer
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin, Madison, Wisconsin
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Boland CL, DeGeeter M, Nuzum DS, Tzefos M. Evaluating Second-Line Treatment Options for Type 2 Diabetes: Focus on Secondary Effects of GLP-1 Agonists and DPP-4 Inhibitors. Ann Pharmacother 2013; 47:490-505. [DOI: 10.1345/aph.1r444] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE To discuss the controversy surrounding selection of second-line type 2 diabetes mellitus (T2DM) therapy by reviewing available data regarding secondary effects of glucagon-like peptide-1 receptor (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors, which include low hypoglycemia risk, weight loss, and cardiovascular (CV) and β-cell function benefits. DATA SOURCES A MEDLINE search (1966–March 2013) was conducted using the following key terms: β-cell protection, blood pressure, DPP-4 inhibitors, exena tide, exenatide extended-release, GLP-1 agonists, hypoglycemia, lina glip tin, lipid, liraglutide, pancreatitis, saxagliptin, sitagliptin, and type 2 diabetes. STUDY SELECTION AND DATA EXTRACTION Identified articles published in English were evaluated for inclusion, with priority given to randomized controlled trials in humans receiving incretin monotherapy or incretin combination therapy with metformin. References identified in these articles were reviewed for additional trials. DATA SYNTHESIS Most patients with T2DM use combination therapy; however, determination of the second-line agent that is most appropriate is debatable. Prior to the use of incretin therapies, traditional second-line agents included sulfonylureas, thiazolidinediones, and basal insulin, all of which demonstrate undesirable adverse effects. In addition to improving glycemic control, incretin therapies have demonstrated benefits concerning hypoglycemic risk and weight loss in addition to potential improvements in CV risk factors and β-cell function. While there are risks associated with using incretins, most patients with T2DM are good candidates for incretins and could benefit from their potential secondary effects. Cost remains a barrier to initiating these agents. CONCLUSIONS Demonstrated secondary benefits in addition to efficacy may make GLP-1 agonists and DPP-4 inhibitors a more favorable option than other second-line T2DM therapies.
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Affiliation(s)
- Cassie L Boland
- Cassie L Boland PharmD BCACP, Assistant Professor of Pharmacy, School of Pharmacy, Wingate University, Wingate, NC
| | - Michelle DeGeeter
- Michelle DeGeeter PharmD, Assistant Professor of Pharmacy, School of Pharmacy, Wingate University
| | - Donald S Nuzum
- Donald S Nuzum PharmD BCACP BC-ADM CPP, Associate Professor of Pharmacy, School of Pharmacy, Wingate University
| | - Maria Tzefos
- Maria Tzefos PharmD BCACP CDE, at time of writing, Assistant Professor of Pharmacy, School of Pharmacy, Wingate University; now, Medical Liaison, Novo-Nordisk, Inc
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Chen KL, Liu SH, Su CC, Yen CC, Yang CY, Lee KI, Tang FC, Chen YW, Lu TH, Su YC, Huang CF. Mercuric compounds induce pancreatic islets dysfunction and apoptosis in vivo. Int J Mol Sci 2012. [PMID: 23202902 PMCID: PMC3497276 DOI: 10.3390/ijms131012349] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mercury is a toxic heavy metal that is an environmental and industrial pollutant throughout the world. Mercury exposure leads to many physiopathological injuries in mammals. However, the precise toxicological effects of mercury on pancreatic islets in vivo are still unclear. Here, we investigated whether mercuric compounds can induce dysfunction and damage in the pancreatic islets of mice, as well as the possible mechanisms involved in this process. Mice were treated with methyl mercuric chloride (MeHgCl, 2 mg/kg) and mercuric chloride (HgCl2, 5 mg/kg) for more than 2 consecutive weeks. Our results showed that the blood glucose levels increased and plasma insulin secretions decreased in the mice as a consequence of their exposure. A significant number of TUNEL-positive cells were revealed in the islets of mice that were treated with mercury for 2 consecutive weeks, which was accompanied by changes in the expression of the mRNA of anti-apoptotic (Bcl-2, Mcl-1, and Mdm-2) and apoptotic (p53, caspase-3, and caspase-7) genes. Moreover, plasma malondialdehyde (MDA) levels increased significantly in the mice after treatment with mercuric compounds for 2 consecutive weeks, and the generation of reactive oxygen species (ROS) in the pancreatic islets also markedly increased. In addition, the mRNA expression of genes related to antioxidation, including Nrf2, GPx, and NQO1, were also significantly reduced in these islets. These results indicate that oxidative stress injuries that are induced by mercuric compounds can cause pancreatic islets dysfunction and apoptosis in vivo.
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Affiliation(s)
- Kuo-Liang Chen
- Department of Urology, China Medical University Hospital, and School of Medicine, China Medical University, No.2 Yuh-Der Rd., Taichung 404, Taiwan; E-Mail:
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, No.1 Jen-Ai Rd., Section 1, Taipei 100, Taiwan; E-Mail:
| | - Chin-Chuan Su
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, No.135 Nanxiao St. Changhua City, Changhua County 500, Taiwan; E-Mail:
| | - Cheng-Chieh Yen
- Department of Occupational Safety and Health, College of Health Care and Management, Chung Shan Medical University; and Department of Occupational Medicine, Chung Shan Medical University Hospital, No. 110 Section 1, Jian-Guo N. Rd., Taichung 402, Taiwan; E-Mail:
| | - Ching-Yao Yang
- Department of Surgery, National Taiwan University Hospital, and Department of Surgery, College of Medicine, National Taiwan University, Taipei 10043, Taiwan; E-Mail:
| | - Kuan-I Lee
- Department of Emergency, Buddhist Tzu Chi General Hospital, Taichung Branch, No. 66 Section 1, Fongsing Rd., Tanzih Township, Taichung 427, Taiwan; E-Mail:
| | - Feng-Cheng Tang
- Department of Occupational Medicine, Changhua Christian Hospital, Changhua 500, Taiwan; E-Mail:
| | - Ya-Wen Chen
- Department of Physiology and Graduate Institute of Basic Medical Science, School of Medicine, College of Medicine, China Medical University, No.91 Hsueh-Shih Rd., Taichung 404, Taiwan; E-Mails: (Y.-W.C.); (T.-H.L.)
| | - Tien-Hui Lu
- Department of Physiology and Graduate Institute of Basic Medical Science, School of Medicine, College of Medicine, China Medical University, No.91 Hsueh-Shih Rd., Taichung 404, Taiwan; E-Mails: (Y.-W.C.); (T.-H.L.)
| | - Yi-Chang Su
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, No.91 Hsueh-Shih Rd., Taichung 404, Taiwan; E-Mail:
| | - Chun-Fa Huang
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, No.91 Hsueh-Shih Rd., Taichung 404, Taiwan; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +886-4-22053366 (ext. 3323); Fax: +886-4-22333641
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Chhoun JM, Voltzke KJ, Firpo MT. From cell culture to a cure: pancreatic β-cell replacement strategies for diabetes mellitus. Regen Med 2012; 7:685-95. [DOI: 10.2217/rme.12.39] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Numerous advances have been made in pancreatic β-cell replacement therapies for diabetes mellitus. While these therapies provide a positive impact and possible cure for the individual recipient, access is limited by availability of donor tissues. The derivation of pluripotent stem cells using efficient differentiation technologies has resulted in the generation of insulin-producing cells with characteristics similar to islet β-cells. Experimental transplantation studies have shown that these cells are capable of reducing hyperglycemia in short-term assays. Novel methodologies that facilitate the neogenesis of β-cells from endogenous hepatic or pancreatic tissue sources are also being investigated as a β-cell replacement strategy. Further research is necessary to protect these transplanted or regenerated cells from diabetic autoimmune pathology.
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Affiliation(s)
- Jennifer M Chhoun
- University of Minnesota, Department of Medicine, 2001 6th Street SE, Minneapolis, MN 55455, USA
| | - Kristin J Voltzke
- University of Minnesota, Department of Medicine, 2001 6th Street SE, Minneapolis, MN 55455, USA
| | - Meri T Firpo
- University of Minnesota, Department of Medicine, 2001 6th Street SE, Minneapolis, MN 55455, USA
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Szabo C. Roles of hydrogen sulfide in the pathogenesis of diabetes mellitus and its complications. Antioxid Redox Signal 2012; 17:68-80. [PMID: 22149162 PMCID: PMC4701125 DOI: 10.1089/ars.2011.4451] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 12/05/2011] [Accepted: 12/11/2011] [Indexed: 12/17/2022]
Abstract
SIGNIFICANCE Diabetes and its complications represent a major socioeconomic problem. RECENT ADVANCES Changes in the balance of hydrogen sulfide (H(2)S) play an important role in the pathogenesis of β-cell dysfunction that occurs in response to type 1 and type 2 diabetes. In addition, changes in H(2)S homeostasis also play a role in the pathogenesis of endothelial injury, which develop on the basis of chronically or intermittently elevated circulating glucose levels in diabetes. CRITICAL ISSUES In the first part of this review, experimental evidence is summarized implicating H(2)S overproduction as a causative factor in the pathogenesis of β-cell death in diabetes. In the second part of our review, experimental evidence is presented supporting the role of H(2)S deficiency (as a result of increased H(2)S consumption by hyperglycemic cells) in the pathogenesis of diabetic endothelial dysfunction, diabetic nephropathy, and cardiomyopathy. FUTURE DIRECTIONS In the final section of the review, future research directions and potential experimental therapeutic approaches around the pharmacological modulation of H(2)S homeostasis in diabetes are discussed.
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Affiliation(s)
- Csaba Szabo
- Department of Anesthesiology, The University of Texas Medical Branch at Galveston, 601 Harborside Drive, Galveston, TX 77555, USA.
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Szabat M, Lynn FC, Hoffman BG, Kieffer TJ, Allan DW, Johnson JD. Maintenance of β-cell maturity and plasticity in the adult pancreas: developmental biology concepts in adult physiology. Diabetes 2012; 61:1365-71. [PMID: 22618775 PMCID: PMC3357305 DOI: 10.2337/db11-1361] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Marta Szabat
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
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Advances and challenges in islet transplantation: islet procurement rates and lessons learned from suboptimal islet transplantation. J Transplant 2011; 2011:979527. [PMID: 22235361 PMCID: PMC3253477 DOI: 10.1155/2011/979527] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Accepted: 10/04/2011] [Indexed: 01/22/2023] Open
Abstract
The initial step in successful islet transplantation is procurement of healthy donor islets. Given the limited number of donor pancreata selected for islet isolation and that islets from multiple donors are typically required to obtain insulin independence, it is critical to improve pancreas procurement rates and yield of islets for transplantation. Islets are delicate microorgans that are susceptible to apoptosis, hypoxia, and ischemia during isolation, culture, and the peritransplant period. Once the islets are engrafted, both prompt revascularization and protection from beta-cell death and graft rejection are key to secure long-term survival and function. To facilitate the engraftment of more robust islets suitable for combating the challenging isolation period and proinflammatory transplantation milieu, numerous approaches have been employed to prevent beta-cell dysfunction and death including immune modulation, prevention of apoptosis and hypoxia, as well as stimulation of growth factors, angiogenesis, and reinnervation. In addition to briefly discussing islet isolation procedures, procurement rates, and islet transplantation, the relevant literature pertaining to successful suboptimal islet transplantation is reviewed to provide insight into potential approaches to balance the limited supply of available donor islets.
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Parnaud G, Gonelle-Gispert C, Morel P, Giovannoni L, Muller YD, Meier R, Borot S, Berney T, Bosco D. Cadherin engagement protects human β-cells from apoptosis. Endocrinology 2011; 152:4601-9. [PMID: 21990317 DOI: 10.1210/en.2011-1286] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The aim of this study was to assess the expression of different types of cadherins in human islets and their role in human β-cell apoptosis. Expression of E-, N-, and P-cadherins was studied by immunofluorescence on pancreas sections and islet cells, and by Western blotting on protein extracts of isolated islets and islet cells. The effects of specific cadherins on cell adhesion and apoptosis were studied using chimeric proteins containing functional E-, N-, or P-cadherin ectodomains fused to Fc fragment of Ig (E-cad/Fc, N-cad/Fc, and P-cad/Fc) and immobilized on glass substrate. β-Cells were identified by immunofluorescence for insulin and apoptotic cells by terminal deoxynucleotide transferase-mediated 2'-deoxyuridine, 5'-triphosphate nick-end labeling. By immunofluorescence, we showed that E- and N-, and not P-, cadherins were expressed at the surface of islet cells. By triple staining, we showed that E-cadherin was expressed at similar extent in β- and α-cells, whereas N-cadherin was preferentially expressed in β-cells. These results were confirmed by Western blot analysis using protein extracts from fluorescence-activated cell sorting-sorted β- and non-β-cells. Adhesion tests showed that the affinity of islet cells for E-cad/Fc and N-cad/Fc and not for P-cad/Fc was increased compared with control. By terminal deoxynucleotide transferase-mediated 2'-deoxyuridine, 5'-triphosphate nick-end labeling, we showed that the percentage of apoptotic cells was lower in aggregated β-cells compared with single β-cells and that attachment to E-cad/Fc and N-cad/Fc and not to P-cad/Fc decreased apoptosis of single β-cells compared with control. Our results show that at least E- and N-cadherins are expressed at the surface of human β-cells and that these adhesion molecules are involved in the maintenance of β-cell viability.
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Affiliation(s)
- Géraldine Parnaud
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, 1211 Geneva 4, Switzerland
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Genome-wide detection of allele specific copy number variation associated with insulin resistance in African Americans from the HyperGEN study. PLoS One 2011; 6:e24052. [PMID: 21901158 PMCID: PMC3162025 DOI: 10.1371/journal.pone.0024052] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 08/01/2011] [Indexed: 01/11/2023] Open
Abstract
African Americans have been understudied in genome wide association studies of diabetes and related traits. In the current study, we examined the joint association of single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) with fasting insulin and an index of insulin resistance (HOMA-IR) in the HyperGEN study, a family based study with proband ascertainment for hypertension. This analysis is restricted to 1,040 African Americans without diabetes. We generated allele specific CNV genotypes at 872,243 autosomal loci using Birdsuite, a freely available multi-stage program. Joint tests of association for SNPs and CNVs were performed using linear mixed models adjusting for covariates and familial relationships. Our results highlight SNPs associated with fasting insulin and HOMA-IR (rs6576507 and rs8026527, 3.7*10−7≤P≤1.1*10−5) near ATPase, class V, type 10A (ATP10A), and the L Type voltage dependent calcium channel (CACNA1D, rs1401492, P≤5.2*10−6). ATP10A belongs to a family of aminophospholipid-transporting ATPases and has been associated with type 2 diabetes in mice. CACNA1D has been linked to pancreatic beta cell generation in mice. The two most significant copy variable markers (rs10277702 and rs361367; P<2.0*10−4) were in the beta variable region of the T-cell receptor gene (TCRVB). Human and mouse TCR has been shown to mimic insulin and its receptor and could contribute to insulin resistance. Our findings differ from genome wide association studies of fasting insulin and other diabetes related traits in European populations, highlighting the continued need to investigate unique genetic influences for understudied populations such as African Americans.
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