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Chen L, Xing X, Zhang P, Chen L, Pei H. Homeostatic regulation of NAD(H) and NADP(H) in cells. Genes Dis 2024; 11:101146. [PMID: 38988322 PMCID: PMC11233901 DOI: 10.1016/j.gendis.2023.101146] [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: 03/28/2023] [Revised: 08/31/2023] [Accepted: 09/11/2023] [Indexed: 07/12/2024] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+)/reduced NAD+ (NADH) and nicotinamide adenine dinucleotide phosphate (NADP+)/reduced NADP+ (NADPH) are essential metabolites involved in multiple metabolic pathways and cellular processes. NAD+ and NADH redox couple plays a vital role in catabolic redox reactions, while NADPH is crucial for cellular anabolism and antioxidant responses. Maintaining NAD(H) and NADP(H) homeostasis is crucial for normal physiological activity and is tightly regulated through various mechanisms, such as biosynthesis, consumption, recycling, and conversion between NAD(H) and NADP(H). The conversions between NAD(H) and NADP(H) are controlled by NAD kinases (NADKs) and NADP(H) phosphatases [specifically, metazoan SpoT homolog-1 (MESH1) and nocturnin (NOCT)]. NADKs facilitate the synthesis of NADP+ from NAD+, while MESH1 and NOCT convert NADP(H) into NAD(H). In this review, we summarize the physiological roles of NAD(H) and NADP(H) and discuss the regulatory mechanisms governing NAD(H) and NADP(H) homeostasis in three key aspects: the transcriptional and posttranslational regulation of NADKs, the role of MESH1 and NOCT in maintaining NAD(H) and NADP(H) homeostasis, and the influence of the circadian clock on NAD(H) and NADP(H) homeostasis. In conclusion, NADKs, MESH1, and NOCT are integral to various cellular processes, regulating NAD(H) and NADP(H) homeostasis. Dysregulation of these enzymes results in various human diseases, such as cancers and metabolic disorders. Hence, strategies aiming to restore NAD(H) and NADP(H) homeostasis hold promise as novel therapeutic approaches for these diseases.
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Affiliation(s)
- Luojun Chen
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, Hubei 430062, China
| | - Xiaoke Xing
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, Hubei 430062, China
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Pingfeng Zhang
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, Hubei 430062, China
| | - Lulu Chen
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, Hubei 430062, China
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Huadong Pei
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
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2
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Rohli KE, Stubbe NJ, Walker EM, Pearson GL, Soleimanpour SA, Stephens SB. A metabolic redox relay supports ER proinsulin export in pancreatic islet β cells. JCI Insight 2024; 9:e178725. [PMID: 38935435 DOI: 10.1172/jci.insight.178725] [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: 12/20/2023] [Accepted: 06/18/2024] [Indexed: 06/29/2024] Open
Abstract
ER stress and proinsulin misfolding are heralded as contributing factors to β cell dysfunction in type 2 diabetes, yet how ER function becomes compromised is not well understood. Recent data identify altered ER redox homeostasis as a critical mechanism that contributes to insulin granule loss in diabetes. Hyperoxidation of the ER delays proinsulin export and limits the proinsulin supply available for insulin granule formation. In this report, we identified glucose metabolism as a critical determinant in the redox homeostasis of the ER. Using multiple β cell models, we showed that loss of mitochondrial function or inhibition of cellular metabolism elicited ER hyperoxidation and delayed ER proinsulin export. Our data further demonstrated that β cell ER redox homeostasis was supported by the metabolic supply of reductive redox donors. We showed that limiting NADPH and thioredoxin flux delayed ER proinsulin export, whereas thioredoxin-interacting protein suppression restored ER redox and proinsulin trafficking. Taken together, we propose that β cell ER redox homeostasis is buffered by cellular redox donor cycles, which are maintained through active glucose metabolism.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Emily M Walker
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Gemma L Pearson
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Scott A Soleimanpour
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- VA Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
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3
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Zhou M, Hanschmann EM, Römer A, Linn T, Petry SF. The significance of glutaredoxins for diabetes mellitus and its complications. Redox Biol 2024; 71:103043. [PMID: 38377787 PMCID: PMC10891345 DOI: 10.1016/j.redox.2024.103043] [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: 12/09/2023] [Accepted: 01/13/2024] [Indexed: 02/22/2024] Open
Abstract
Diabetes mellitus is a non-communicable metabolic disease hallmarked by chronic hyperglycemia caused by beta-cell failure. Diabetic complications affect the vasculature and result in macro- and microangiopathies, which account for a significantly increased morbidity and mortality. The rising incidence and prevalence of diabetes is a major global health burden. There are no feasible strategies for beta-cell preservation available in daily clinical practice. Therefore, patients rely on antidiabetic drugs or the application of exogenous insulin. Glutaredoxins (Grxs) are ubiquitously expressed and highly conserved members of the thioredoxin family of proteins. They have specific functions in redox-mediated signal transduction, iron homeostasis and biosynthesis of iron-sulfur (FeS) proteins, and the regulation of cell proliferation, survival, and function. The involvement of Grxs in chronic diseases has been a topic of research for several decades, suggesting them as therapeutic targets. Little is known about their role in diabetes and its complications. Therefore, this review summarizes the available literature on the significance of Grxs in diabetes and its complications. In conclusion, Grxs are differentially expressed in the endocrine pancreas and in tissues affected by diabetic complications, such as the heart, the kidneys, the eye, and the vasculature. They are involved in several pathways essential for insulin signaling, metabolic inflammation, glucose and fatty acid uptake and processing, cell survival, and iron and mitochondrial metabolism. Most studies describe significant changes in glutaredoxin expression and/or activity in response to the diabetic metabolism. In general, mitigated levels of Grxs are associated with oxidative distress, cell damage, and even cell death. The induced overexpression is considered a potential part of the cellular stress-response, counteracting oxidative distress and exerting beneficial impact on cell function such as insulin secretion, cytokine expression, and enzyme activity.
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Affiliation(s)
- Mengmeng Zhou
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Eva-Maria Hanschmann
- Experimental and Translational Research, Department of Otorhinolaryngology, University Hospital Essen, Essen, Germany
| | - Axel Römer
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Thomas Linn
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Sebastian Friedrich Petry
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany.
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4
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Lin H, Suzuki K, Smith N, Li X, Nalbach L, Fuentes S, Spigelman AF, Dai XQ, Bautista A, Ferdaoussi M, Aggarwal S, Pepper AR, Roma LP, Ampofo E, Li WH, MacDonald PE. A role and mechanism for redox sensing by SENP1 in β-cell responses to high fat feeding. Nat Commun 2024; 15:334. [PMID: 38184650 PMCID: PMC10771529 DOI: 10.1038/s41467-023-44589-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 12/21/2023] [Indexed: 01/08/2024] Open
Abstract
Pancreatic β-cells respond to metabolic stress by upregulating insulin secretion, however the underlying mechanisms remain unclear. Here we show, in β-cells from overweight humans without diabetes and mice fed a high-fat diet for 2 days, insulin exocytosis and secretion are enhanced without increased Ca2+ influx. RNA-seq of sorted β-cells suggests altered metabolic pathways early following high fat diet, where we find increased basal oxygen consumption and proton leak, but a more reduced cytosolic redox state. Increased β-cell exocytosis after 2-day high fat diet is dependent on this reduced intracellular redox state and requires the sentrin-specific SUMO-protease-1. Mice with either pancreas- or β-cell-specific deletion of this fail to up-regulate exocytosis and become rapidly glucose intolerant after 2-day high fat diet. Mechanistically, redox-sensing by the SUMO-protease requires a thiol group at C535 which together with Zn+-binding suppresses basal protease activity and unrestrained β-cell exocytosis, and increases enzyme sensitivity to regulation by redox signals.
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Affiliation(s)
- Haopeng Lin
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Guangzhou Laboratory, Guangzhou, 510005, Guangdong, China
| | - Kunimasa Suzuki
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Nancy Smith
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Xi Li
- Departments of Cell Biology and Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, USA
| | - Lisa Nalbach
- Institute for Clinical & Experimental Surgery, Saarland University, Homburg/Saar, Germany
- Biophysics Department, Center for Human and Molecular Biology, Saarland University, Homburg/Saar, Germany
| | - Sonia Fuentes
- Departments of Cell Biology and Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, USA
| | - Aliya F Spigelman
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Xiao-Qing Dai
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Austin Bautista
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Mourad Ferdaoussi
- Faculty Saint-Jean, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Saloni Aggarwal
- Department of Surgery, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Andrew R Pepper
- Department of Surgery, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Leticia P Roma
- Biophysics Department, Center for Human and Molecular Biology, Saarland University, Homburg/Saar, Germany
| | - Emmanuel Ampofo
- Institute for Clinical & Experimental Surgery, Saarland University, Homburg/Saar, Germany
| | - Wen-Hong Li
- Departments of Cell Biology and Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, USA
| | - Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
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Shao Z, Wang S, Liu N, Wang W, Zhu L. Interactions between sulfonamide homologues and glycosyltransferase induced metabolic disorders in rice (Oryza sativa L.). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 336:122486. [PMID: 37669699 DOI: 10.1016/j.envpol.2023.122486] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/24/2023] [Accepted: 08/30/2023] [Indexed: 09/07/2023]
Abstract
Sulfadiazine and its derivatives (sulfonamides, SAs) could induce distinct biotoxic, metabolic and physiological abnormalities, potentially due to their subtle structural differences. This study conducted an in-depth investigation on the interactions between SA homologues, i.e. sulfadiazine (SD), sulfamerazine (SD1), and sulfamethazine (SD2), and the key metabolic enzyme (glycosyltransferase, GT) in rice (Oryza sativa L.). Untargeted screening of SA metabolites revealed that GT-catalyzed glycosylation was the primary transformation pathway of SAs in rice. Molecular docking identified that the binding sites of SAs on GT (D0TZD6) were responsible for transferring sugar moiety to synthesize polysaccharides and detoxify SAs. Specifically, amino acids in the GT-binding cavity (e.g., GLY487 and CYS486) formed stable hydrogen bonds with SAs (e.g., the sulfonamide group of SD). Molecular dynamics simulations revealed that SAs induced conformational changes in GT ligand binding domain, which was supported by the significantly decreased GT activity and gene expression level. As evidenced by proteomics and metabolomics, SAs inhibited the transfer and synthesis of sugar but stimulated sugar decomposition in rice leaves, leading to the accumulation of mono- and disaccharides in rice leaves. While the differences in the increased sugar content by SD (24.3%, compared with control), SD1 (11.1%), and SD2 (6.24%) can be attributed to their number of methyl groups (0, 1, 2, respectively), which determined the steric hindrance and hydrogen bonds formation with GT. This study suggested that the disturbances on crop sugar metabolism by homologues contaminants are determined by the interaction between the contaminants and the target enzyme, and are greatly dependent on the steric hindrance effects contributed by their side chains. The results are of importance to identify priority pollutants and ensure crop quality in contaminated fields.
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Affiliation(s)
- Zexi Shao
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Shuyuan Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Na Liu
- College of Environment and Resources, Xiangtan University, Xiangtan, 411105, China
| | - Wei Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Lizhong Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China.
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6
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Wei B, Zhang X, Qian J, Tang Z, Zhang B. Nrf2: Therapeutic target of islet function protection in diabetes and islet transplantation. Biomed Pharmacother 2023; 167:115463. [PMID: 37703659 DOI: 10.1016/j.biopha.2023.115463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023] Open
Abstract
Nuclear factor-erythroid 2-related factor 2 (Nrf2) has been reported as a major intracellular regulator of antioxidant stress, notably in islet β cells with low antioxidant enzyme content. Nrf2 is capable of regulating antioxidant function, while it can also regulate insulin secretion, proliferation, and differentiation of β cells, ER stress, as well as mitochondrial function. Thus, Nrf2 pharmacological activators have been employed in the laboratory for the treatment of diabetic mice. Islet cells are exposed to oxidative environment when islet is being transplanted. Accordingly, less than 50% of islet cells are well transplanted, and their normal function is maintained. The pharmacological activation of Nrf2 has been confirmed to protect islet cells at different stages of transplantation stages during experiments for islet transplantation.
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Affiliation(s)
- Butian Wei
- Department of general Surgery, The Fourth affiliated Hospital, Zhejiang university School of Medicine, Yiwu 322000, China
| | - Xin Zhang
- Department of general Surgery, The Fourth affiliated Hospital, Zhejiang university School of Medicine, Yiwu 322000, China
| | - Jiwei Qian
- Department of general Surgery, The Fourth affiliated Hospital, Zhejiang university School of Medicine, Yiwu 322000, China
| | - Zhe Tang
- Department of general Surgery, The Fourth affiliated Hospital, Zhejiang university School of Medicine, Yiwu 322000, China
| | - Bo Zhang
- Department of general Surgery, The Second affiliated Hospital, Zhejiang university School of Medicine, Hangzhou 310000, China.
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Zhang YL, An Y, Sun LJ, Qu HL, Li X, He XT, Wu RX, Chen FM, Tian BM, Yin Y. NADPH-dependent ROS accumulation contributes to the impaired osteogenic differentiation of periodontal ligament stem cells under high glucose conditions. Front Endocrinol (Lausanne) 2023; 14:1152845. [PMID: 37351108 PMCID: PMC10282952 DOI: 10.3389/fendo.2023.1152845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/19/2023] [Indexed: 06/24/2023] Open
Abstract
Diabetes mellitus is an established risk factor for periodontal disease that can aggravate the severity of periodontal inflammation and accelerate periodontal destruction. The chronic high glucose condition is a hallmark of diabetes-related pathogenesis, and has been demonstrated to impair the osteogenic differentiation of periodontal ligament stem cells (PDLSCs), leading to delayed recovery of periodontal defects in diabetic patients. Reactive oxygen species (ROS) are small molecules that can influence cell fate determination and the direction of cell differentiation. Although excessive accumulation of ROS has been found to be associated with high glucose-induced cell damage, the underlying mechanisms remain unclear. Nicotinamide adenine dinucleotide phosphate (NADPH) is an important electron donor and functions as a critical ROS scavenger in antioxidant systems. It has been identified as a key mediator of various biological processes, including energy metabolism and cell differentiation. However, whether NADPH is involved in the dysregulation of ROS and further compromise of PDLSC osteogenic differentiation under high glucose conditions is still not known. In the present study, we found that PDLSCs incubated under high glucose conditions showed impaired osteogenic differentiation, excessive ROS accumulation and increased NADPH production. Furthermore, after inhibiting the synthesis of NADPH, the osteogenic differentiation of PDLSCs was significantly enhanced, accompanied by reduced cellular ROS accumulation. Our findings demonstrated the crucial role of NADPH in regulating cellular osteogenic differentiation under high glucose conditions and suggested a new target for rescuing high glucose-induced cell dysfunction and promoting tissue regeneration in the future.
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Affiliation(s)
| | | | | | | | | | | | | | - Fa-Ming Chen
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Bei-Min Tian
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Yuan Yin
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, Fourth Military Medical University, Xi’an, China
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8
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Li K, Bian J, Xiao Y, Wang D, Han L, He C, Gong L, Wang M. Changes in Pancreatic Senescence Mediate Pancreatic Diseases. Int J Mol Sci 2023; 24:ijms24043513. [PMID: 36834922 PMCID: PMC9962587 DOI: 10.3390/ijms24043513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/12/2023] Open
Abstract
In recent years, there has been a significant increase in age-related diseases due to the improvement in life expectancy worldwide. The pancreas undergoes various morphological and pathological changes with aging, such as pancreatic atrophy, fatty degeneration, fibrosis, inflammatory cell infiltration, and exocrine pancreatic metaplasia. Meanwhile, these may predispose the individuals to aging-related diseases, such as diabetes, dyspepsia, pancreatic ductal adenocarcinoma, and pancreatitis, as the endocrine and exocrine functions of the pancreas are significantly affected by aging. Pancreatic senescence is associated with various underlying factors including genetic damage, DNA methylation, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and inflammation. This paper reviews the alternations of morphologies and functions in the aging pancreas, especially β-cells, closely related to insulin secretion. Finally, we summarize the mechanisms of pancreatic senescence to provide potential targets for treating pancreatic aging-related diseases.
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Affiliation(s)
- Kailin Li
- College of Food Science and Engineering, Northwest A & F University, Yangling, Xianyang 712100, China
| | - Ji Bian
- Kolling Institute, Sydney Medical School, Royal North Shore Hospital, University of Sydney, St. Leonards, NSW 2065, Australia
| | - Yao Xiao
- College of Food Science and Engineering, Northwest A & F University, Yangling, Xianyang 712100, China
| | - Da Wang
- College of Food Science and Engineering, Northwest A & F University, Yangling, Xianyang 712100, China
| | - Lin Han
- College of Food Science and Engineering, Northwest A & F University, Yangling, Xianyang 712100, China
| | - Caian He
- College of Food Science and Engineering, Northwest A & F University, Yangling, Xianyang 712100, China
| | - Lan Gong
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, NSW 2052, Australia
- Correspondence: (L.G.); (M.W.)
| | - Min Wang
- College of Food Science and Engineering, Northwest A & F University, Yangling, Xianyang 712100, China
- Correspondence: (L.G.); (M.W.)
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9
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Ishihara H. Metabolism-secretion coupling in glucose-stimulated insulin secretion. Diabetol Int 2022; 13:463-470. [PMID: 35693987 PMCID: PMC9174369 DOI: 10.1007/s13340-022-00576-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 02/27/2022] [Indexed: 01/09/2023]
Abstract
Pancreatic β-cells in the islets of Langerhans secrete insulin in response to blood glucose levels. Precise control of the amount of insulin secreted is of critical importance for maintaining systemic carbohydrate homeostasis. It is now well established that glucose induced production of ATP from ADP and the KATP channel closure elevate cytosolic Ca2+, triggering insulin exocytosis in β-cells. However, for full activation of insulin secretion by glucose, other mechanisms besides Ca2+ elevation are needed. These mechanisms are the targets of current research and include intracellular metabolic pathways branching from glycolysis. They are metabolic pathways originating from the TCA cycle intermediates, the glycerolipid/free fatty acid cycle and the pentose phosphate pathway. Signaling effects of these pathways including degradation (removal) of protein SUMOylation, modulation of insulin vesicular energetics, and lipid modulation of exocytotic machinery may converge to fulfill insulin secretion, though the precise mechanisms have yet to be elucidated. This mini-review summarize recent advances in research on metabolic coupling mechanisms functioning in insulin secretion.
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Affiliation(s)
- Hisamitsu Ishihara
- Division of Diabetes and Metabolism, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo, 173-8610 Japan
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10
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Luseogliflozin preserves the pancreatic beta-cell mass and function in db/db mice by improving mitochondrial function. Sci Rep 2022; 12:9740. [PMID: 35697838 PMCID: PMC9192642 DOI: 10.1038/s41598-022-13888-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 05/30/2022] [Indexed: 11/20/2022] Open
Abstract
We aimed to determine the mechanism by which the sodium glucose co-transporter 2 inhibitor, luseogliflozin, preserves pancreatic beta-cell mass and function in db/db mice. Six-week-old db/db mice were fed to standard chow or standard chow containing 0.01% luseogliflozin. After 4 weeks, DNA microarray analysis, real-time PCR analysis, and measurement of mitochondrial respiratory capacity and reactive oxygen species (ROS) generation were performed using isolated islets. Immunohistochemistry and electron microscopic analysis were performed using pancreatic tissues. Metabolites extracted from the islets were measured by capillary electrophoresis mass spectrometry. The expression of genes involved in the tricarboxylic acid (TCA) cycle and electron transport chain was upregulated by luseogliflozin. Luseogliflozin improved the mitochondrial complex II-linked oxidative phosphorylation capacity and reduced ROS generation. Mitochondrial morphology was normally maintained by luseogliflozin. Luseogliflozin increased NK6 homeobox 1 (NKX6.1) expression and TCA cycle metabolites. Relief of glucotoxicity by luseogliflozin may involve lower mitochondrial ROS generation and an improvement in complex II-linked mitochondrial respiration. Reducing ROS generation through preventing complex II damage likely increases NKX6.1 expression and ameliorate glucose metabolism in the TCA cycle, contributing to the protection of pancreatic beta-cells. Protection of complex II in pancreatic beta-cells represents a novel therapeutic target for type 2 diabetes.
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11
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Ježek P, Holendová B, Jabůrek M, Dlasková A, Plecitá-Hlavatá L. Contribution of Mitochondria to Insulin Secretion by Various Secretagogues. Antioxid Redox Signal 2022; 36:920-952. [PMID: 34180254 PMCID: PMC9125579 DOI: 10.1089/ars.2021.0113] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Significance: Mitochondria determine glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells by elevating ATP synthesis. As the metabolic and redox hub, mitochondria provide numerous links to the plasma membrane channels, insulin granule vesicles (IGVs), cell redox, NADH, NADPH, and Ca2+ homeostasis, all affecting insulin secretion. Recent Advances: Mitochondrial redox signaling was implicated in several modes of insulin secretion (branched-chain ketoacid [BCKA]-, fatty acid [FA]-stimulated). Mitochondrial Ca2+ influx was found to enhance GSIS, reflecting cytosolic Ca2+ oscillations induced by action potential spikes (intermittent opening of voltage-dependent Ca2+ and K+ channels) or the superimposed Ca2+ release from the endoplasmic reticulum (ER). The ATPase inhibitory factor 1 (IF1) was reported to tune the glucose sensitivity range for GSIS. Mitochondrial protein kinase A was implicated in preventing the IF1-mediated inhibition of the ATP synthase. Critical Issues: It is unknown how the redox signal spreads up to the plasma membrane and what its targets are, what the differences in metabolic, redox, NADH/NADPH, and Ca2+ signaling, and homeostasis are between the first and second GSIS phase, and whether mitochondria can replace ER in the amplification of IGV exocytosis. Future Directions: Metabolomics studies performed to distinguish between the mitochondrial matrix and cytosolic metabolites will elucidate further details. Identifying the targets of cell signaling into mitochondria and of mitochondrial retrograde metabolic and redox signals to the cell will uncover further molecular mechanisms for insulin secretion stimulated by glucose, BCKAs, and FAs, and the amplification of secretion by glucagon-like peptide (GLP-1) and metabotropic receptors. They will identify the distinction between the hub β-cells and their followers in intact and diabetic states. Antioxid. Redox Signal. 36, 920-952.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Andrea Dlasková
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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12
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Rohli KE, Boyer CK, Blom SE, Stephens SB. Nutrient Regulation of Pancreatic Islet β-Cell Secretory Capacity and Insulin Production. Biomolecules 2022; 12:335. [PMID: 35204835 PMCID: PMC8869698 DOI: 10.3390/biom12020335] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 01/27/2023] Open
Abstract
Pancreatic islet β-cells exhibit tremendous plasticity for secretory adaptations that coordinate insulin production and release with nutritional demands. This essential feature of the β-cell can allow for compensatory changes that increase secretory output to overcome insulin resistance early in Type 2 diabetes (T2D). Nutrient-stimulated increases in proinsulin biosynthesis may initiate this β-cell adaptive compensation; however, the molecular regulators of secretory expansion that accommodate the increased biosynthetic burden of packaging and producing additional insulin granules, such as enhanced ER and Golgi functions, remain poorly defined. As these adaptive mechanisms fail and T2D progresses, the β-cell succumbs to metabolic defects resulting in alterations to glucose metabolism and a decline in nutrient-regulated secretory functions, including impaired proinsulin processing and a deficit in mature insulin-containing secretory granules. In this review, we will discuss how the adaptative plasticity of the pancreatic islet β-cell's secretory program allows insulin production to be carefully matched with nutrient availability and peripheral cues for insulin signaling. Furthermore, we will highlight potential defects in the secretory pathway that limit or delay insulin granule biosynthesis, which may contribute to the decline in β-cell function during the pathogenesis of T2D.
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Affiliation(s)
- Kristen E. Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K. Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E. Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Samuel B. Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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13
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Glucose-6-phosphatase catalytic subunit 2 negatively regulates glucose oxidation and insulin secretion in pancreatic β-cells. J Biol Chem 2022; 298:101729. [PMID: 35176280 PMCID: PMC8941207 DOI: 10.1016/j.jbc.2022.101729] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 12/11/2022] Open
Abstract
Elevated fasting blood glucose (FBG) is associated with increased risks of developing type 2 diabetes (T2D) and cardiovascular-associated mortality. G6PC2 is predominantly expressed in islets, encodes a glucose-6-phosphatase catalytic subunit that converts glucose-6-phosphate (G6P) to glucose, and has been linked with variations in FBG in genome-wide association studies. Deletion of G6pc2 in mice has been shown to lower FBG without affecting fasting plasma insulin levels in vivo. At 5 mM glucose, pancreatic islets from G6pc2 knockout (KO) mice exhibit no glucose cycling, increased glycolytic flux, and enhanced glucose-stimulated insulin secretion (GSIS). However, the broader effects of G6pc2 KO on β-cell metabolism and redox regulation are unknown. Here we used CRISPR/Cas9 gene editing and metabolic flux analysis in βTC3 cells, a murine pancreatic β-cell line, to examine the role of G6pc2 in regulating glycolytic and mitochondrial fluxes. We found that deletion of G6pc2 led to ∼60% increases in glycolytic and citric acid cycle (CAC) fluxes at both 5 and 11 mM glucose concentrations. Furthermore, intracellular insulin content and GSIS were enhanced by approximately two-fold, along with increased cytosolic redox potential and reductive carboxylation flux. Normalization of fluxes relative to net glucose uptake revealed upregulation in two NADPH-producing pathways in the CAC. These results demonstrate that G6pc2 regulates GSIS by modulating not only glycolysis but also, independently, citric acid cycle activity in β-cells. Overall, our findings implicate G6PC2 as a potential therapeutic target for enhancing insulin secretion and lowering FBG, which could benefit individuals with prediabetes, T2D, and obesity.
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14
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Prevention of Lipotoxicity in Pancreatic Islets with Gammahydroxybutyrate. Cells 2022; 11:cells11030545. [PMID: 35159354 PMCID: PMC8833960 DOI: 10.3390/cells11030545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/28/2022] [Accepted: 01/30/2022] [Indexed: 02/06/2023] Open
Abstract
Oxidative stress caused by the exposure of pancreatic ß-cells to high levels of fatty acids impairs insulin secretion. This lipotoxicity is thought to play an important role in ß-cell failure in type 2 diabetes and can be prevented by antioxidants. Gamma-hydroxybutyrate (GHB), an endogenous antioxidant and energy source, has previously been shown to protect mice from streptozotocin and alloxan-induced diabetes; both compounds are generators of oxidative stress and yield models of type-1 diabetes. We sought to determine whether GHB could protect mouse islets from lipotoxicity caused by palmitate, a model relevant to type 2 diabetes. We found that GHB prevented the generation of palmitate-induced reactive oxygen species and the associated lipotoxic inhibition of glucose-stimulated insulin secretion while increasing the NADPH/NADP+ ratio. GHB may owe its antioxidant and insulin secretory effects to the formation of NADPH.
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15
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Upregulation of α enolase (ENO1) crotonylation in colorectal cancer and its promoting effect on cancer cell metastasis. Biochem Biophys Res Commun 2021; 578:77-83. [PMID: 34547627 DOI: 10.1016/j.bbrc.2021.09.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 09/14/2021] [Indexed: 12/17/2022]
Abstract
Lysine crotonylation (Kcr) is a newly identified protein translational modification and is involved in major biological processes including glycolysis, but its role in colorectal cancer (CRC) is unknown. Here, we found that the Kcr of α enolase (ENO1) was significantly elevated in human CRC tissues compared with the paratumoral tissues. CREB-binding protein (CBP) functioned as a crotonyltranferase of ENO1, and SIRT2 was involved in the decrotonylation of ENO1. Using quantitative mass spectrometry for crotonylomics analysis, we further found that K420 was the main Kcr site of ENO1 and ENO1 K420 Kcr promoted the growth, migration, and invasion of CRC cells in vitro by enhancing the activity of ENO1 and regulating the expression of tumor-associated genes. Our study reveals an important mechanism by which ENO1 regulates CRC through crotonylation.
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16
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Cumpstey AF, Clark AD, Santolini J, Jackson AA, Feelisch M. COVID-19: A Redox Disease-What a Stress Pandemic Can Teach Us About Resilience and What We May Learn from the Reactive Species Interactome About Its Treatment. Antioxid Redox Signal 2021; 35:1226-1268. [PMID: 33985343 DOI: 10.1089/ars.2021.0017] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Significance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), affects every aspect of human life by challenging bodily, socioeconomic, and political systems at unprecedented levels. As vaccines become available, their distribution, safety, and efficacy against emerging variants remain uncertain, and specific treatments are lacking. Recent Advances: Initially affecting the lungs, COVID-19 is a complex multisystems disease that disturbs the whole-body redox balance and can be long-lasting (Long-COVID). Numerous risk factors have been identified, but the reasons for variations in susceptibility to infection, disease severity, and outcome are poorly understood. The reactive species interactome (RSI) was recently introduced as a framework to conceptualize how cells and whole organisms sense, integrate, and accommodate stress. Critical Issues: We here consider COVID-19 as a redox disease, offering a holistic perspective of its effects on the human body, considering the vulnerability of complex interconnected systems with multiorgan/multilevel interdependencies. Host/viral glycan interactions underpin SARS-CoV-2's extraordinary efficiency in gaining cellular access, crossing the epithelial/endothelial barrier to spread along the vascular/lymphatic endothelium, and evading antiviral/antioxidant defences. An inflammation-driven "oxidative storm" alters the redox landscape, eliciting epithelial, endothelial, mitochondrial, metabolic, and immune dysfunction, and coagulopathy. Concomitantly reduced nitric oxide availability renders the sulfur-based redox circuitry vulnerable to oxidation, with eventual catastrophic failure in redox communication/regulation. Host nutrient limitations are crucial determinants of resilience at the individual and population level. Future Directions: While inflicting considerable damage to health and well-being, COVID-19 may provide the ultimate testing ground to improve the diagnosis and treatment of redox-related stress diseases. "Redox phenotyping" of patients to characterize whole-body RSI status as the disease progresses may inform new therapeutic approaches to regain redox balance, reduce mortality in COVID-19 and other redox diseases, and provide opportunities to tackle Long-COVID. Antioxid. Redox Signal. 35, 1226-1268.
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Affiliation(s)
- Andrew F Cumpstey
- Respiratory and Critical Care Research Group, Southampton NIHR Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Anna D Clark
- Respiratory and Critical Care Research Group, Southampton NIHR Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Jérôme Santolini
- Institute for Integrative Biology of the Cell (I2BC), Biochemistry, Biophysics and Structural Biology, CEA, CNRS, Université Paris-Sud, Universite Paris-Saclay, Gif-sur-Yvette, France
| | - Alan A Jackson
- Human Nutrition, University of Southampton and University Hospital Southampton, Southampton, United Kingdom
| | - Martin Feelisch
- Respiratory and Critical Care Research Group, Southampton NIHR Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
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17
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Close AF, Chae H, Jonas JC. The lack of functional nicotinamide nucleotide transhydrogenase only moderately contributes to the impairment of glucose tolerance and glucose-stimulated insulin secretion in C57BL/6J vs C57BL/6N mice. Diabetologia 2021; 64:2550-2561. [PMID: 34448880 DOI: 10.1007/s00125-021-05548-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/26/2021] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS Nicotinamide nucleotide transhydrogenase (NNT) is involved in mitochondrial NADPH production and its spontaneous inactivating mutation (NntTr [Tr, truncated]) is usually considered to be the main cause of the lower glucose tolerance of C57BL/6J vs C57BL/6N mice. However, the impact of this mutation on glucose tolerance remains disputed. Here, we singled out the impact of NntTr from that of other genetic variants between C57BL/6J and C57BL/6N mice on mitochondrial glutathione redox state (EGSH), glucose-stimulated insulin secretion (GSIS) and glucose tolerance. METHODS Male and female N5BL/6J mice that express wild-type Nnt (NntWT) or NntTr (N5-WT and N5-Tr mice) on the C57BL/6J genetic background were obtained by crossing N5BL/6J NntWT/Tr heterozygous mice. C57BL/6J and C57BL/6N mice were from Janvier Labs. The Nnt genotype was confirmed by PCR and the genetic background by whole genome sequencing of one mouse of each type. Glucose tolerance was assessed by IPGTT, ITT and fasting/refeeding tests. Stimulus-secretion coupling events and GSIS were measured in isolated pancreatic islets. Cytosolic and mitochondrial EGSH were measured using the fluorescent redox probe GRX1-roGFP2 (glutaredoxin 1 fused to redox-sensitive enhanced GFP). RESULTS The Nnt genotype and genetic background of each type of mouse were confirmed. As reported previously in C57BL/6N vs C57BL/6J islets, the glucose regulation of mitochondrial (but not cytosolic) EGSH and of NAD(P)H autofluorescence was markedly improved in N5-WT vs N5-Tr islets, confirming the role of NNT in mitochondrial redox regulation. However, ex vivo GSIS was only 1.2-1.4-times higher in N5-WT vs N5-Tr islets, while it was 2.4-times larger in C57BL/6N vs N5-WT islets, questioning the role of NNT in GSIS. In vivo, the ITT results did not differ between N5-WT and N5-Tr or C57BL/6N mice. However, the glucose excursion during an IPGTT was only 15-20% lower in female N5-WT mice than in N5-Tr and C57BL/6J mice and remained 3.5-times larger than in female C57BL/6N mice. Similar observations were made during a fasting/refeeding test. A slightly larger (~30%) impact of NNT on glucose tolerance was found in males. CONCLUSIONS/INTERPRETATION Although our results confirm the importance of NNT in the regulation of mitochondrial redox state by glucose, they markedly downsize the role of NNT in the alteration of GSIS and glucose tolerance in C57BL/6J vs C57BL/6N mice. Therefore, documenting an NntWT genotype in C57BL/6 mice does not provide proof that their glucose tolerance is as good as in C57BL/6N mice.
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Affiliation(s)
- Anne-Françoise Close
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Heeyoung Chae
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Jean-Christophe Jonas
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium.
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18
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Walker JT, Saunders DC, Brissova M, Powers AC. The Human Islet: Mini-Organ With Mega-Impact. Endocr Rev 2021; 42:605-657. [PMID: 33844836 PMCID: PMC8476939 DOI: 10.1210/endrev/bnab010] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 02/08/2023]
Abstract
This review focuses on the human pancreatic islet-including its structure, cell composition, development, function, and dysfunction. After providing a historical timeline of key discoveries about human islets over the past century, we describe new research approaches and technologies that are being used to study human islets and how these are providing insight into human islet physiology and pathophysiology. We also describe changes or adaptations in human islets in response to physiologic challenges such as pregnancy, aging, and insulin resistance and discuss islet changes in human diabetes of many forms. We outline current and future interventions being developed to protect, restore, or replace human islets. The review also highlights unresolved questions about human islets and proposes areas where additional research on human islets is needed.
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Affiliation(s)
- John T Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Diane C Saunders
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Marcela Brissova
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.,Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,VA Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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19
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Wei X, Lu Z, Li L, Zhang H, Sun F, Ma H, Wang L, Hu Y, Yan Z, Zheng H, Yang G, Liu D, Tepel M, Gao P, Zhu Z. Reducing NADPH Synthesis Counteracts Diabetic Nephropathy through Restoration of AMPK Activity in Type 1 Diabetic Rats. Cell Rep 2021; 32:108207. [PMID: 32997989 DOI: 10.1016/j.celrep.2020.108207] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 07/11/2020] [Accepted: 09/09/2020] [Indexed: 01/14/2023] Open
Abstract
Diabetic nephropathy (DN) is a major complication of diabetes mellitus and a primary cause of end-stage renal failure. Clinical studies indicate that metabolic surgery improves DN; however, the mechanism remains unclear. Here, we report that Roux-en-Y Gastric Bypass (RYGB) surgery significantly blocked and reversed DN without affecting the insulin signaling pathway. This protective role of RYGB surgery is almost blocked by either inhibition or knockout of 5'AMP-activated protein kinase (AMPK) in podocytes. Furthermore, mRNA microarray data reveal that RYGB surgery obviously reduced the gene expression involved in nicotinamide adenine dinucleotide phosphate (NAPDH) synthesis. The expression of a key NADPH synthase, hexose-6-phosphate dehydrogenase (H6PD), was inhibited by the low plasma corticosterone level after surgery. In addition, blocking NAPDH synthesis by knocking down H6PD mimicked the beneficial role of RYGB surgery through activation of AMPK in podocytes. Therefore, this study demonstrates that reducing NADPH production is critical for renal AMPK activation in response to RYGB surgery.
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Affiliation(s)
- Xiao Wei
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Zongshi Lu
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Li Li
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Hexuan Zhang
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Fang Sun
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Huan Ma
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Lijuan Wang
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Yingru Hu
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Zhencheng Yan
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Hongting Zheng
- Department of Endocrinology, Translational Research Key Laboratory for Diabetes, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Gangyi Yang
- Department of Endocrinology, The Second Affiliated Hospital, Chongqing Medical University and Chongqing Clinical Research Center for Geriatrics, Chongqing 400010, China
| | - Daoyan Liu
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China
| | - Martin Tepel
- Odense University Hospital, Department of Nephrology, University of Southern Denmark, Institute for Molecular Medicine, Cardiovascular and Renal Research, Institute of Clinical Research, Odense, Denmark
| | - Peng Gao
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China.
| | - Zhiming Zhu
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Army Medical University, Chongqing Institute of Hypertension, Chongqing 400042, China.
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20
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Vilas-Boas EA, Carlein C, Nalbach L, Almeida DC, Ampofo E, Carpinelli AR, Roma LP, Ortis F. Early Cytokine-Induced Transient NOX2 Activity Is ER Stress-Dependent and Impacts β-Cell Function and Survival. Antioxidants (Basel) 2021; 10:antiox10081305. [PMID: 34439552 PMCID: PMC8389306 DOI: 10.3390/antiox10081305] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 01/23/2023] Open
Abstract
In type 1 diabetes (T1D) development, proinflammatory cytokines (PIC) released by immune cells lead to increased reactive oxygen species (ROS) production in β-cells. Nonetheless, the temporality of the events triggered and the role of different ROS sources remain unclear. Isolated islets from C57BL/6J wild-type (WT), NOX1 KO and NOX2 KO mice were exposed to a PIC combination. We show that cytokines increase O2•− production after 2 h in WT and NOX1 KO but not in NOX2 KO islets. Using transgenic mice constitutively expressing a genetically encoded compartment specific H2O2 sensor, we show, for the first time, a transient increase of cytosolic/nuclear H2O2 in islet cells between 4 and 5 h during cytokine exposure. The H2O2 increase coincides with the intracellular NAD(P)H decrease and is absent in NOX2 KO islets. NOX2 KO confers better glucose tolerance and protects against cytokine-induced islet secretory dysfunction and death. However, NOX2 absence does not counteract the cytokine effects in ER Ca2+ depletion, Store-Operated Calcium Entry (SOCE) increase and ER stress. Instead, the activation of ER stress precedes H2O2 production. As early NOX2-driven ROS production impacts β-cells’ function and survival during insulitis, NOX2 might be a potential target for designing therapies against early β-cell dysfunction in the context of T1D onset.
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Affiliation(s)
- Eloisa A. Vilas-Boas
- Center for Human and Molecular Biology (ZHMB), Department of Biophysics, Saarland University, 66424 Homburg, Germany; (E.A.V.-B.); (C.C.)
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, SP, Brazil;
| | - Christopher Carlein
- Center for Human and Molecular Biology (ZHMB), Department of Biophysics, Saarland University, 66424 Homburg, Germany; (E.A.V.-B.); (C.C.)
| | - Lisa Nalbach
- Institute for Clinical and Experimental Surgery, Saarland University, 66424 Homburg, Germany; (L.N.); (E.A.)
| | - Davidson C. Almeida
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, SP, Brazil;
| | - Emmanuel Ampofo
- Institute for Clinical and Experimental Surgery, Saarland University, 66424 Homburg, Germany; (L.N.); (E.A.)
| | - Angelo R. Carpinelli
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, SP, Brazil;
| | - Leticia P. Roma
- Center for Human and Molecular Biology (ZHMB), Department of Biophysics, Saarland University, 66424 Homburg, Germany; (E.A.V.-B.); (C.C.)
- Correspondence: (L.P.R.); (F.O.); Tel.: +06841-16-16240 (L.P.R.); +55-(11)-3091-0923 (F.O.); Fax: +06841-16-16302 (L.P.R.)
| | - Fernanda Ortis
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, SP, Brazil;
- Correspondence: (L.P.R.); (F.O.); Tel.: +06841-16-16240 (L.P.R.); +55-(11)-3091-0923 (F.O.); Fax: +06841-16-16302 (L.P.R.)
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21
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Bauchle CJ, Rohli KE, Boyer CK, Pal V, Rocheleau JV, Liu S, Imai Y, Taylor EB, Stephens SB. Mitochondrial Efflux of Citrate and Isocitrate Is Fully Dispensable for Glucose-Stimulated Insulin Secretion and Pancreatic Islet β-Cell Function. Diabetes 2021; 70:1717-1728. [PMID: 34039628 PMCID: PMC8385611 DOI: 10.2337/db21-0037] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/22/2021] [Indexed: 11/13/2022]
Abstract
The defining feature of pancreatic islet β-cell function is the precise coordination of changes in blood glucose levels with insulin secretion to regulate systemic glucose homeostasis. While ATP has long been heralded as a critical metabolic coupling factor to trigger insulin release, glucose-derived metabolites have been suggested to further amplify fuel-stimulated insulin secretion. The mitochondrial export of citrate and isocitrate through the citrate-isocitrate carrier (CIC) has been suggested to initiate a key pathway that amplifies glucose-stimulated insulin secretion, though the physiological significance of β-cell CIC-to-glucose homeostasis has not been established. Here, we generated constitutive and adult CIC β-cell knockout (KO) mice and demonstrate that these animals have normal glucose tolerance, similar responses to diet-induced obesity, and identical insulin secretion responses to various fuel secretagogues. Glucose-stimulated NADPH production was impaired in β-cell CIC KO islets, whereas glutathione reduction was retained. Furthermore, suppression of the downstream enzyme cytosolic isocitrate dehydrogenase (Idh1) inhibited insulin secretion in wild-type islets but failed to impact β-cell function in β-cell CIC KO islets. Our data demonstrate that the mitochondrial CIC is not required for glucose-stimulated insulin secretion and that additional complexities exist for the role of Idh1 and NADPH in the regulation of β-cell function.
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Affiliation(s)
- Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
| | - Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Department of Pharmacology, University of Iowa, Iowa City, IA
| | - Vidhant Pal
- Institute of Biomedical Engineering, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jonathan V Rocheleau
- Institute of Biomedical Engineering, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Siming Liu
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
| | - Yumi Imai
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA
- Iowa City Veterans Affairs Medical Center, Iowa City, IA
| | - Eric B Taylor
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA
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Benáková Š, Holendová B, Plecitá-Hlavatá L. Redox Homeostasis in Pancreatic β-Cells: From Development to Failure. Antioxidants (Basel) 2021; 10:antiox10040526. [PMID: 33801681 PMCID: PMC8065646 DOI: 10.3390/antiox10040526] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/16/2022] Open
Abstract
Redox status is a key determinant in the fate of β-cell. These cells are not primarily detoxifying and thus do not possess extensive antioxidant defense machinery. However, they show a wide range of redox regulating proteins, such as peroxiredoxins, thioredoxins or thioredoxin reductases, etc., being functionally compartmentalized within the cells. They keep fragile redox homeostasis and serve as messengers and amplifiers of redox signaling. β-cells require proper redox signaling already in cell ontogenesis during the development of mature β-cells from their progenitors. We bring details about redox-regulated signaling pathways and transcription factors being essential for proper differentiation and maturation of functional β-cells and their proliferation and insulin expression/maturation. We briefly highlight the targets of redox signaling in the insulin secretory pathway and focus more on possible targets of extracellular redox signaling through secreted thioredoxin1 and thioredoxin reductase1. Tuned redox homeostasis can switch upon chronic pathological insults towards the dysfunction of β-cells and to glucose intolerance. These are characteristics of type 2 diabetes, which is often linked to chronic nutritional overload being nowadays a pandemic feature of lifestyle. Overcharged β-cell metabolism causes pressure on proteostasis in the endoplasmic reticulum, mainly due to increased demand on insulin synthesis, which establishes unfolded protein response and insulin misfolding along with excessive hydrogen peroxide production. This together with redox dysbalance in cytoplasm and mitochondria due to enhanced nutritional pressure impact β-cell redox homeostasis and establish prooxidative metabolism. This can further affect β-cell communication in pancreatic islets through gap junctions. In parallel, peripheral tissues losing insulin sensitivity and overall impairment of glucose tolerance and gut microbiota establish local proinflammatory signaling and later systemic metainflammation, i.e., low chronic inflammation prooxidative properties, which target β-cells leading to their dedifferentiation, dysfunction and eventually cell death.
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Affiliation(s)
- Štěpánka Benáková
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- First Faculty of Medicine, Charles University, Katerinska 1660/32, 121 08 Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- Department of Mitochondrial Physiology, Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
- Correspondence: ; Tel.: +420-296-442-285
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Ahn M, Oh E, McCown EM, Wang X, Veluthakal R, Thurmond DC. A requirement for PAK1 to support mitochondrial function and maintain cellular redox balance via electron transport chain proteins to prevent β-cell apoptosis. Metabolism 2021; 115:154431. [PMID: 33181191 PMCID: PMC8123936 DOI: 10.1016/j.metabol.2020.154431] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/04/2020] [Accepted: 11/07/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVE p21 (Cdc42/Rac1) activated Kinase 1 (PAK1) is a candidate susceptibility factor for type 2 diabetes (T2D). PAK1 is depleted in the islets from T2D donors, compared to control individuals. In addition, whole-body PAK1 knock out (PAK1-KO) in mice worsens the T2D-like effects of high-fat diet. The current study tested the effects of modulating PAK1 levels only in β-cells. MATERIALS/METHODS β-cell-specific inducible PAK1 KO (βPAK1-iKO) mice were generated and used with human β-cells and T2D islets to evaluate β-cell function. RESULTS βPAK1-iKO mice exhibited glucose intolerance and elevated β-cell apoptosis, but without peripheral insulin resistance. β-cells from βPAK-iKO mice also contained fewer mitochondria per cell. At the cellular level, human PAK1-deficient β-cells showed blunted glucose-stimulated insulin secretion and reduced mitochondrial function. Mitochondria from human PAK1-deficient β-cells were deficient in the electron transport chain (ETC) subunits CI, CIII, and CIV; NDUFA12, a CI complex protein, was identified as a novel PAK1 binding partner, and was significantly reduced with PAK1 knockdown. PAK1 knockdown disrupted the NAD+/NADH and NADP+/NADPH ratios, and elevated ROS. An imbalance of the redox state due to mitochondrial dysfunction leads to ER stress in β-cells. PAK1 replenishment in the β-cells of T2D human islets ameliorated levels of ER stress markers. CONCLUSIONS These findings support a protective function for PAK1 in β-cells. The results support a new model whereby the PAK1 in the β-cell plays a required role upstream of mitochondrial function, via maintaining ETC protein levels and averting stress-induced β-cell apoptosis to retain healthy functional β-cell mass.
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Affiliation(s)
- Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute at the City of Hope, Duarte, CA 91010, United States of America
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute at the City of Hope, Duarte, CA 91010, United States of America
| | - Erika M McCown
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute at the City of Hope, Duarte, CA 91010, United States of America
| | - Xin Wang
- Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute at the City of Hope, Duarte, CA 91010, United States of America
| | - Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute at the City of Hope, Duarte, CA 91010, United States of America.
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Ježek P, Holendová B, Jabůrek M, Tauber J, Dlasková A, Plecitá-Hlavatá L. The Pancreatic β-Cell: The Perfect Redox System. Antioxidants (Basel) 2021; 10:antiox10020197. [PMID: 33572903 PMCID: PMC7912581 DOI: 10.3390/antiox10020197] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell insulin secretion, which responds to various secretagogues and hormonal regulations, is reviewed here, emphasizing the fundamental redox signaling by NADPH oxidase 4- (NOX4-) mediated H2O2 production for glucose-stimulated insulin secretion (GSIS). There is a logical summation that integrates both metabolic plus redox homeostasis because the ATP-sensitive K+ channel (KATP) can only be closed when both ATP and H2O2 are elevated. Otherwise ATP would block KATP, while H2O2 would activate any of the redox-sensitive nonspecific calcium channels (NSCCs), such as TRPM2. Notably, a 100%-closed KATP ensemble is insufficient to reach the -50 mV threshold plasma membrane depolarization required for the activation of voltage-dependent Ca2+ channels. Open synergic NSCCs or Cl- channels have to act simultaneously to reach this threshold. The resulting intermittent cytosolic Ca2+-increases lead to the pulsatile exocytosis of insulin granule vesicles (IGVs). The incretin (e.g., GLP-1) amplification of GSIS stems from receptor signaling leading to activating the phosphorylation of TRPM channels and effects on other channels to intensify integral Ca2+-influx (fortified by endoplasmic reticulum Ca2+). ATP plus H2O2 are also required for branched-chain ketoacids (BCKAs); and partly for fatty acids (FAs) to secrete insulin, while BCKA or FA β-oxidation provide redox signaling from mitochondria, which proceeds by H2O2 diffusion or hypothetical SH relay via peroxiredoxin "redox kiss" to target proteins.
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25
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Brüning D, Hatlapatka K, Lier-Glaubitz V, Andermark V, Scherneck S, Ott I, Rustenbeck I. Pharmacological inhibition of thioredoxin reductase increases insulin secretion and diminishes beta cell viability. Naunyn Schmiedebergs Arch Pharmacol 2021; 394:1133-1142. [PMID: 33464387 PMCID: PMC8208932 DOI: 10.1007/s00210-020-02046-2] [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: 12/10/2019] [Accepted: 12/22/2020] [Indexed: 11/18/2022]
Abstract
Apparently, both a decrease in beta cell function and in beta cell mass contribute to the progressive worsening of type 2 diabetes. So, it is of particular interest to define factors which are relevant for the regulation of insulin secretion and at the same time for the maintenance of beta cell mass. The NADPH-thioredoxin system has a candidate role for such a dual function. Here, we have characterized the effects of a highly specific inhibitor of thioredoxin reductase, AM12, on the viability and function of insulin-secreting MIN6 cells and isolated NMRI mouse islets. Viability was checked by MTT testing and the fluorescent live-dead assay. Apoptosis was assessed by annexin V assay. Insulin secretion of perifused islets was measured by ELISA. The cytosolic Ca2+ concentration was measured by the Fura technique. Acute exposure of perifused pancreatic islets to 5 μM AM12 was without significant effect on insulin secretion. Islets cultured for 24 h in 0.5 or 5 μM AM12 showed unchanged basal secretion during perifusion, but the response to 30 mM glucose was significantly enhanced by 5 μM. Twenty-four-hour exposure to 5 μM AM12 proved to be without effect on the viability of MIN6 cells, whereas longer exposure was clearly toxic. Islets were more susceptible, showing initial signs of apoptosis after 24-h exposure to 5 μM AM12. The activity of the NADPH-thioredoxin system is indispensable for beta cell viability but may have a limiting effect on glucose-induced insulin secretion.
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Affiliation(s)
- Dennis Brüning
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Kathrin Hatlapatka
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Verena Lier-Glaubitz
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Vincent Andermark
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Stephan Scherneck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Ingo Ott
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D-38106, Braunschweig, Germany.
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26
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Campbell JE, Newgard CB. Mechanisms controlling pancreatic islet cell function in insulin secretion. Nat Rev Mol Cell Biol 2021; 22:142-158. [PMID: 33398164 DOI: 10.1038/s41580-020-00317-7] [Citation(s) in RCA: 255] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 02/07/2023]
Abstract
Metabolic homeostasis in mammals is tightly regulated by the complementary actions of insulin and glucagon. The secretion of these hormones from pancreatic β-cells and α-cells, respectively, is controlled by metabolic, endocrine, and paracrine regulatory mechanisms and is essential for the control of blood levels of glucose. The deregulation of these mechanisms leads to various pathologies, most notably type 2 diabetes, which is driven by the combined lesions of impaired insulin action and a loss of the normal insulin secretion response to glucose. Glucose stimulates insulin secretion from β-cells in a bi-modal fashion, and new insights about the underlying mechanisms, particularly relating to the second or amplifying phase of this secretory response, have been recently gained. Other recent work highlights the importance of α-cell-produced proglucagon-derived peptides, incretin hormones from the gastrointestinal tract and other dietary components, including certain amino acids and fatty acids, in priming and potentiation of the β-cell glucose response. These advances provide a new perspective for the understanding of the β-cell failure that triggers type 2 diabetes.
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Affiliation(s)
- Jonathan E Campbell
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA.,Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC, USA.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA. .,Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC, USA. .,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.
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27
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Chareyron I, Christen S, Moco S, Valsesia A, Lassueur S, Dayon L, Wollheim CB, Santo Domingo J, Wiederkehr A. Augmented mitochondrial energy metabolism is an early response to chronic glucose stress in human pancreatic beta cells. Diabetologia 2020; 63:2628-2640. [PMID: 32960311 PMCID: PMC7641954 DOI: 10.1007/s00125-020-05275-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/04/2020] [Indexed: 01/15/2023]
Abstract
AIMS/HYPOTHESIS In islets from individuals with type 2 diabetes and in islets exposed to chronic elevated glucose, mitochondrial energy metabolism is impaired. Here, we studied early metabolic changes and mitochondrial adaptations in human beta cells during chronic glucose stress. METHODS Respiration and cytosolic ATP changes were measured in human islet cell clusters after culture for 4 days in 11.1 mmol/l glucose. Metabolomics was applied to analyse intracellular metabolite changes as a result of glucose stress conditions. Alterations in beta cell function were followed using insulin secretion assays or cytosolic calcium signalling after expression of the calcium probe YC3.6 specifically in beta cells of islet clusters. RESULTS At early stages of glucose stress, mitochondrial energy metabolism was augmented in contrast to the previously described mitochondrial dysfunction in beta cells from islets of diabetic donors. Following chronic glucose stress, mitochondrial respiration increased (by 52.4%, p < 0.001) and, as a consequence, the cytosolic ATP/ADP ratio in resting human pancreatic islet cells was elevated (by 27.8%, p < 0.05). Because of mitochondrial overactivation in the resting state, nutrient-induced beta cell activation was reduced. In addition, chronic glucose stress caused metabolic adaptations that resulted in the accumulation of intermediates of the glycolytic pathway, the pentose phosphate pathway and the TCA cycle; the most strongly augmented metabolite was glycerol 3-phosphate. The changes in metabolites observed are likely to be due to the inability of mitochondria to cope with continuous nutrient oversupply. To protect beta cells from chronic glucose stress, we inhibited mitochondrial pyruvate transport. Metabolite concentrations were partially normalised and the mitochondrial respiratory response to nutrients was markedly improved. Furthermore, stimulus-secretion coupling as assessed by cytosolic calcium signalling, was restored. CONCLUSION/INTERPRETATION We propose that metabolic changes and associated mitochondrial overactivation are early adaptations to glucose stress, and may reflect what happens as a result of poor blood glucose control. Inhibition of mitochondrial pyruvate transport reduces mitochondrial nutrient overload and allows beta cells to recover from chronic glucose stress. Graphical abstract.
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Affiliation(s)
- Isabelle Chareyron
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Stefan Christen
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
| | - Sofia Moco
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
| | - Armand Valsesia
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
| | - Steve Lassueur
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
| | - Loïc Dayon
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Claes B Wollheim
- Department of Cell Physiology and Metabolism, University Medical Center, Geneva, Switzerland
| | - Jaime Santo Domingo
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland
| | - Andreas Wiederkehr
- Nestlé Institute of Health Sciences, Nestlé Research, EPFL Innovation Park, Lausanne, Switzerland.
- Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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28
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Sha W, Hu F, Bu S. Mitochondrial dysfunction and pancreatic islet β-cell failure (Review). Exp Ther Med 2020; 20:266. [PMID: 33199991 PMCID: PMC7664595 DOI: 10.3892/etm.2020.9396] [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: 02/18/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023] Open
Abstract
Pancreatic β-cells are the only source of insulin in humans. Mitochondria uses pyruvate to produce ATP as an intermediate link between glucose intake and insulin secretion in β-cells, in a process known as glucose-stimulated insulin secretion (GSIS). Previous studies have demonstrated that GSIS is negatively regulated by various factors in the mitochondria, including tRNALeu mutations, high p58 expression, reduced nicotinamide nucleotide transhydrogenase activity, abnormal levels of uncoupling proteins and reduced expression levels of transcription factors A, B1 and B2. Additionally, oxidative stress damages mitochondria and impairs antioxidant defense mechanisms, leading to the increased production of reactive oxygen species, which induces β-cell dysfunction. Inflammation in islets can also damage β-cell physiology. Inflammatory cytokines trigger the release of cytochrome c from the mitochondria via the NF-κB pathway. The present review examined the potential factors underlying mitochondrial dysfunction and their association with islet β-cell failure, which may offer novel insights regarding future strategies for the preservation of mitochondrial function and enhancement of antioxidant activity for individuals with diabetes mellitus.
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Affiliation(s)
- Wenxin Sha
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Fei Hu
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Shizhong Bu
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
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29
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Plecitá-Hlavatá L, Engstová H, Holendová B, Tauber J, Špaček T, Petrásková L, Křen V, Špačková J, Gotvaldová K, Ježek J, Dlasková A, Smolková K, Ježek P. Mitochondrial Superoxide Production Decreases on Glucose-Stimulated Insulin Secretion in Pancreatic β Cells Due to Decreasing Mitochondrial Matrix NADH/NAD + Ratio. Antioxid Redox Signal 2020; 33:789-815. [PMID: 32517485 PMCID: PMC7482716 DOI: 10.1089/ars.2019.7800] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 12/19/2022]
Abstract
Aims: Glucose-stimulated insulin secretion (GSIS) in pancreatic β cells was expected to enhance mitochondrial superoxide formation. Hence, we elucidated relevant redox equilibria. Results: Unexpectedly, INS-1E cells at transitions from 3 (11 mM; pancreatic islets from 5 mM) to 25 mM glucose decreased matrix superoxide release rates (MitoSOX Red monitoring validated by MitoB) and H2O2 (mitoHyPer, subtracting mitoSypHer emission). Novel double-channel fluorescence lifetime imaging, approximating free mitochondrial matrix NADHF, indicated its ∼20% decrease. Matrix NAD+F increased on GSIS, indicated by the FAD-emission lifetime decrease, reflecting higher quenching of FAD by NAD+F. The participation of pyruvate/malate and pyruvate/citrate redox shuttles, elevating cytosolic NADPHF (iNAP1 fluorescence monitoring) at the expense of matrix NADHF, was indicated, using citrate (2-oxoglutarate) carrier inhibitors and cytosolic malic enzyme silencing: All changes vanished on these manipulations. 13C-incorporation from 13C-L-glutamine into 13C-citrate reflected the pyruvate/isocitrate shuttle. Matrix NADPHF (iNAP3 monitored) decreased. With decreasing glucose, the suppressor of Complex III site Q electron leak (S3QEL) suppressor caused a higher Complex I IF site contribution, but a lower superoxide fraction ascribed to the Complex III site IIIQo. Thus, the diminished matrix NADHF/NAD+F decreased Complex I flavin site IF superoxide formation on GSIS. Innovation: Mutually validated methods showed decreasing superoxide release into the mitochondrial matrix in pancreatic β cells on GSIS, due to the decreasing matrix NADHF/NAD+F (NADPHF/NADP+F) at increasing cytosolic NADPHF levels. The developed innovative methods enable real-time NADH/NAD+ and NADPH/NADP+ monitoring in any distinct cell compartment. Conclusion: The export of reducing equivalents from mitochondria adjusts lower mitochondrial superoxide production on GSIS, but it does not prevent oxidative stress in pancreatic β cells.
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Affiliation(s)
- Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Engstová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Tauber
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Špaček
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lucie Petrásková
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vladimír Křen
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jitka Špačková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Klára Gotvaldová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
| | - Andrea Dlasková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Katarína Smolková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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30
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Xie N, Zhang L, Gao W, Huang C, Huber PE, Zhou X, Li C, Shen G, Zou B. NAD + metabolism: pathophysiologic mechanisms and therapeutic potential. Signal Transduct Target Ther 2020; 5:227. [PMID: 33028824 PMCID: PMC7539288 DOI: 10.1038/s41392-020-00311-7] [Citation(s) in RCA: 372] [Impact Index Per Article: 93.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/04/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) and its metabolites function as critical regulators to maintain physiologic processes, enabling the plastic cells to adapt to environmental changes including nutrient perturbation, genotoxic factors, circadian disorder, infection, inflammation and xenobiotics. These effects are mainly achieved by the driving effect of NAD+ on metabolic pathways as enzyme cofactors transferring hydrogen in oxidation-reduction reactions. Besides, multiple NAD+-dependent enzymes are involved in physiology either by post-synthesis chemical modification of DNA, RNA and proteins, or releasing second messenger cyclic ADP-ribose (cADPR) and NAADP+. Prolonged disequilibrium of NAD+ metabolism disturbs the physiological functions, resulting in diseases including metabolic diseases, cancer, aging and neurodegeneration disorder. In this review, we summarize recent advances in our understanding of the molecular mechanisms of NAD+-regulated physiological responses to stresses, the contribution of NAD+ deficiency to various diseases via manipulating cellular communication networks and the potential new avenues for therapeutic intervention.
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Affiliation(s)
- Na Xie
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Lu Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Wei Gao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Canhua Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 611137, China
| | - Peter Ernst Huber
- CCU Molecular and Radiation Oncology, German Cancer Research Center; Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Xiaobo Zhou
- First Department of Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - Changlong Li
- West China School of Basic Medical Sciences & Forensic Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Guobo Shen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China.
| | - Bingwen Zou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China.
- CCU Molecular and Radiation Oncology, German Cancer Research Center; Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.
- Department of Thoracic Oncology and Department of Radiation Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
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Abstract
Anaplerosis and the associated mitochondrial metabolite transporters generate unique cytosolic metabolic signaling molecules that can regulate insulin release from pancreatic β-cells. It has been shown that mitochondrial metabolites, transported by the citrate carrier (CIC), dicarboxylate carrier (DIC), oxoglutarate carrier (OGC), and mitochondrial pyruvate carrier (MPC) play a vital role in the regulation of glucose-stimulated insulin secretion (GSIS). Metabolomic studies on static and biphasic insulin secretion, suggests that several anaplerotic derived metabolites, including α-ketoglutarate (αKG), are strongly associated with nutrient regulated insulin secretion. Support for a role of αKG in the regulation of insulin secretion comes from studies looking at αKG dependent enzymes, including hypoxia-inducible factor-prolyl hydroxylases (PHDs) in clonal β-cells, and rodent and human islets. This review will focus on the possible link between defective anaplerotic-derived αKG, PHDs, and the development of type 2 diabetes (T2D).
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Affiliation(s)
- M. Hoang
- School of Pharmacy, University of Waterloo, Kitchener, Ontario, Canada
| | - J. W. Joseph
- School of Pharmacy, University of Waterloo, Kitchener, Ontario, Canada
- CONTACT J. W. Joseph School of Pharmacy, University of Waterloo, Kitchener, ONN2G1C5, Canada
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32
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Mitochondrial GTP Links Nutrient Sensing to β Cell Health, Mitochondrial Morphology, and Insulin Secretion Independent of OxPhos. Cell Rep 2020; 28:759-772.e10. [PMID: 31315053 DOI: 10.1016/j.celrep.2019.06.058] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 02/15/2019] [Accepted: 06/14/2019] [Indexed: 12/18/2022] Open
Abstract
Mechanisms coordinating pancreatic β cell metabolism with insulin secretion are essential for glucose homeostasis. One key mechanism of β cell nutrient sensing uses the mitochondrial GTP (mtGTP) cycle. In this cycle, mtGTP synthesized by succinyl-CoA synthetase (SCS) is hydrolyzed via mitochondrial PEPCK (PEPCK-M) to make phosphoenolpyruvate, a high-energy metabolite that integrates TCA cycling and anaplerosis with glucose-stimulated insulin secretion (GSIS). Several strategies, including xenotopic overexpression of yeast mitochondrial GTP/GDP exchanger (GGC1) and human ATP and GTP-specific SCS isoforms, demonstrated the importance of the mtGTP cycle. These studies confirmed that mtGTP triggers and amplifies normal GSIS and rescues defects in GSIS both in vitro and in vivo. Increased mtGTP synthesis enhanced calcium oscillations during GSIS. mtGTP also augmented mitochondrial mass, increased insulin granule number, and membrane proximity without triggering de-differentiation or metabolic fragility. These data highlight the importance of the mtGTP signal in nutrient sensing, insulin secretion, mitochondrial maintenance, and β cell health.
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Ferdaoussi M, Smith N, Lin H, Bautista A, Spigelman AF, Lyon J, Dai X, Manning Fox JE, MacDonald PE. Improved glucose tolerance with DPPIV inhibition requires β-cell SENP1 amplification of glucose-stimulated insulin secretion. Physiol Rep 2020; 8:e14420. [PMID: 32339440 PMCID: PMC7185381 DOI: 10.14814/phy2.14420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 01/09/2023] Open
Abstract
Pancreatic islet insulin secretion is amplified by both metabolic and receptor-mediated signaling pathways. The incretin-mimetic and DPPIV inhibitor anti-diabetic drugs increase insulin secretion, but in humans this can be variable both in vitro and in vivo. We examined the correlation of GLP-1 induced insulin secretion from human islets with key donor characteristics, glucose-responsiveness, and the ability of glucose to augment exocytosis in β-cells. No clear correlation was observed between several donor or organ processing parameters and the ability of Exendin 4 to enhance insulin secretion. The ability of glucose to facilitate β-cell exocytosis was, however, significantly correlated with responses to Exendin 4. We therefore studied the effect of impaired glucose-dependent amplification of insulin exocytosis on responses to DPPIV inhibition (MK-0626) in vivo using pancreas and β-cell specific sentrin-specific protease-1 (SENP1) mice which exhibit impaired metabolic amplification of insulin exocytosis. Glucose tolerance was improved, and plasma insulin was increased, following either acute or 4 week treatment of wild-type (βSENP1+/+ ) mice with MK-0626. This DPPIV inhibitor was ineffective in βSENP1+/- or βSENP1- / - mice. Finally, we confirm impaired exocytotic responses of β-cells and reduced insulin secretion from islets of βSENP1- / - mice and show that the ability of Exendin 4 to enhance exocytosis is lost in these cells. Thus, an impaired ability of glucose to amplify insulin exocytosis results in a deficient effect of DPPIV inhibition to improve in vivo insulin responses and glucose tolerance.
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Affiliation(s)
- Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Nancy Smith
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Haopeng Lin
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Austin Bautista
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Aliya F. Spigelman
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - James Lyon
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - XiaoQing Dai
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Jocelyn E. Manning Fox
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
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Bouzakri K, Veyrat-Durebex C, Holterman C, Arous C, Barbieux C, Bosco D, Altirriba J, Alibashe M, Tournier BB, Gunton JE, Mouche S, Bietiger W, Forterre A, Berney T, Pinget M, Christofori G, Kennedy C, Szanto I. Beta-Cell-Specific Expression of Nicotinamide Adenine Dinucleotide Phosphate Oxidase 5 Aggravates High-Fat Diet-Induced Impairment of Islet Insulin Secretion in Mice. Antioxid Redox Signal 2020; 32:618-635. [PMID: 31931619 DOI: 10.1089/ars.2018.7579] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aims: Nicotinamide adenine dinucleotide phosphate oxidases (NOX-es) produce reactive oxygen species and modulate β-cell insulin secretion. Islets of type 2 diabetic subjects present elevated expression of NOX5. Here, we sought to characterize regulation of NOX5 expression in human islets in vitro and to uncover the relevance of NOX5 in islet function in vivo using a novel mouse model expressing NOX5 in doxycycline-inducible, β-cell-specific manner (RIP/rtTA/NOX5 mice). Results:In situ hybridization and immunohistochemistry employed on pancreatic sections demonstrated NOX5 messenger ribonucleic acid (mRNA) and protein expressions in human islets. In cultures of dispersed islets, NOX5 protein was observed in somatostatin-positive (δ) cells in basal (2.8 mM glucose) conditions. Small interfering ribonucleic acid (siRNA)-mediated knockdown of NOX5 in human islets cultured in basal glucose concentrations resulted in diminished glucose-induced insulin secretion (GIIS) in vitro. However, when islets were preincubated in high (16.7 mM) glucose media for 12 h, NOX5 appeared also in insulin-positive (β) cells. In vivo, mice with β-cell NOX5 expression developed aggravated impairment of GIIS compared with control mice when challenged with 14 weeks of high-fat diet. Similarly, in vitro palmitate preincubation resulted in more severe reduction of insulin release in islets of RIP/rtTA/NOX5 mice compared with their control littermates. Decreased insulin secretion was most distinct in response to theophylline stimulation, suggesting impaired cyclic adenosine monophosphate (cAMP)-mediated signaling due to increased phosphodiesterase activation. Innovation and Conclusions: Our data provide the first insight into the complex regulation and function of NOX5 in islets implying an important role for NOX5 in δ-cell-mediated intraislet crosstalk in physiological circumstances but also identifying it as an aggravating factor in β-cell failure in diabetic conditions.
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Affiliation(s)
- Karim Bouzakri
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.,Centre Européen d'Etude du Diabète, Strasbourg, France
| | | | - Chet Holterman
- Division of Nephrology, Department of Medicine, Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Caroline Arous
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.,Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Charlotte Barbieux
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Jordi Altirriba
- Laboratory of Metabolism, Department of Internal Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Mohamed Alibashe
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Benjamin B Tournier
- Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland
| | - Jenny E Gunton
- Centre for Diabetes, Obesity and Endocrinology, Westmead Millennium Institute, The University of Sydney, Sydney, Australia.,Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, Australia
| | - Sarah Mouche
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland.,Department of Internal Medicine, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | | | | | - Thierry Berney
- Division of Transplantation, Department of Surgery, University Hospitals of Geneva, Geneva, Switzerland
| | - Michel Pinget
- Centre Européen d'Etude du Diabète, Strasbourg, France
| | | | - Christopher Kennedy
- Division of Nephrology, Department of Medicine, Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Ildiko Szanto
- Department of Internal Medicine, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.,Diabetes Center of the Faculty of Medicine at the University of Geneva, Geneva, Switzerland
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Metabolomics Analysis of Nutrient Metabolism in β-Cells. J Mol Biol 2020; 432:1429-1445. [DOI: 10.1016/j.jmb.2019.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/03/2019] [Accepted: 07/11/2019] [Indexed: 01/05/2023]
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Prentki M, Corkey BE, Madiraju SRM. Lipid-associated metabolic signalling networks in pancreatic beta cell function. Diabetologia 2020; 63:10-20. [PMID: 31423551 DOI: 10.1007/s00125-019-04976-w] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/29/2019] [Indexed: 01/01/2023]
Abstract
Significant advances have been made in deciphering the mechanisms underlying fuel-stimulated insulin secretion by pancreatic beta cells. The contribution of the triggering/ATP-sensitive potassium (KATP)-dependent Ca2+ signalling and KATP-independent amplification pathways, that include anaplerosis and lipid signalling of glucose-stimulated insulin secretion (GSIS), are well established. A proposed model included a key role for a metabolic partitioning 'switch', the acetyl-CoA carboxylase (ACC)/malonyl-CoA/carnitine palmitoyltransferase-1 (CPT-1) axis, in beta cell glucose and fatty acid signalling for insulin secretion. This model has gained overwhelming support from a number of studies in recent years and is now refined through its link to the glycerolipid/NEFA cycle that provides lipid signals through its lipolysis arm. Furthermore, acetyl-CoA carboxylase may also control beta cell growth. Here we review the evidence supporting a role for the ACC/malonyl-CoA/CPT-1 axis in the control of GSIS and its particular importance under conditions of elevated fatty acids (e.g. fasting, excess nutrients, hyperlipidaemia and diabetes). We also document how it is linked to a more global lipid signalling system that includes the glycerolipid/NEFA cycle.
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Affiliation(s)
- Marc Prentki
- Department of Nutrition, University of Montreal, Montréal, QC, Canada.
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montréal, QC, Canada.
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Viger Tour, 900 rue Saint Denis, Room R08-412, Montréal, QC, H2X 0A9, Canada.
| | - Barbara E Corkey
- Evans Department of Medicine, Obesity Research Center, Boston University School of Medicine, Boston, MA, USA
| | - S R Murthy Madiraju
- Department of Nutrition, University of Montreal, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montréal, QC, Canada
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Viger Tour, 900 rue Saint Denis, Room R08-412, Montréal, QC, H2X 0A9, Canada
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Wortham M, Benthuysen JR, Wallace M, Savas JN, Mulas F, Divakaruni AS, Liu F, Albert V, Taylor BL, Sui Y, Saez E, Murphy AN, Yates JR, Metallo CM, Sander M. Integrated In Vivo Quantitative Proteomics and Nutrient Tracing Reveals Age-Related Metabolic Rewiring of Pancreatic β Cell Function. Cell Rep 2019; 25:2904-2918.e8. [PMID: 30517875 PMCID: PMC6317899 DOI: 10.1016/j.celrep.2018.11.031] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 09/06/2018] [Accepted: 11/05/2018] [Indexed: 01/02/2023] Open
Abstract
Pancreatic β cell physiology changes substantially throughout life, yet the mechanisms that drive these changes are poorly understood. Here, we performed comprehensive in vivo quantitative proteomic profiling of pancreatic islets from juvenile and 1-year-old mice. The analysis revealed striking differences in abundance of enzymes controlling glucose metabolism. We show that these changes in protein abundance are associated with higher activities of glucose metabolic enzymes involved in coupling factor generation as well as increased activity of the coupling factor-dependent amplifying pathway of insulin secretion. Nutrient tracing and targeted metabolomics demonstrated accelerated accumulation of glucose-derived metabolites and coupling factors in islets from 1-year-old mice, indicating that age-related changes in glucose metabolism contribute to improved glucose-stimulated insulin secretion with age. Together, our study provides an in-depth characterization of age-related changes in the islet proteome and establishes metabolic rewiring as an important mechanism for age-associated changes in β cell function. Organismal age impacts fundamental aspects of β cell physiology. Wortham et al. apply proteomics and targeted metabolomics to islets from juvenile and adult mice, revealing age-related changes in metabolic enzyme abundance and production of coupling factors that enhance insulin secretion. This work provides insight into age-associated changes to the β cell.
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Affiliation(s)
- Matthew Wortham
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jacqueline R Benthuysen
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Martina Wallace
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92037, USA
| | - Jeffrey N Savas
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Francesca Mulas
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ajit S Divakaruni
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Fenfen Liu
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Verena Albert
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Brandon L Taylor
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yinghui Sui
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Enrique Saez
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Christian M Metallo
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92037, USA
| | - Maike Sander
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA.
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Roma LP, Jonas JC. Nutrient Metabolism, Subcellular Redox State, and Oxidative Stress in Pancreatic Islets and β-Cells. J Mol Biol 2019; 432:1461-1493. [PMID: 31634466 DOI: 10.1016/j.jmb.2019.10.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/25/2019] [Accepted: 10/10/2019] [Indexed: 01/01/2023]
Abstract
Insulin-secreting pancreatic β-cells play a critical role in blood glucose homeostasis and the development of type 2 diabetes (T2D) in the context of insulin resistance. Based on data obtained at the whole cell level using poorly specific chemical probes, reactive oxygen species (ROS) such as superoxide and hydrogen peroxide have been proposed to contribute to the stimulation of insulin secretion by nutrients (positive role) and to the alterations of cell survival and secretory function in T2D (negative role). This raised the controversial hypothesis that any attempt to decrease β-cell oxidative stress and apoptosis in T2D would further impair insulin secretion. Over the last decade, the development of genetically-encoded redox probes that can be targeted to cellular compartments of interest and are specific of redox couples allowed the evaluation of short- and long-term effects of nutrients on β-cell redox changes at the subcellular level. The data indicated that the nutrient regulation of β-cell redox signaling and ROS toxicity is far more complex than previously thought and that the subcellular compartmentation of these processes cannot be neglected when evaluating the mechanisms of ROS production or the efficacy of antioxidant enzymes and antioxidant drugs under glucolipotoxic conditions and in T2D. In this review, we present what is currently known about the compartmentation of redox homeostatic systems and tools to investigate it. We then review data about the effects of nutrients on β-cell subcellular redox state under normal conditions and in the context of T2D and discuss challenges and opportunities in the field.
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Affiliation(s)
- Leticia P Roma
- Universität des Saarlandes, Biophysics Department, Center for Human and Molecular Biology, Kirbergerstrasse Building 48, 66421, Homburg/Saar, Germany
| | - Jean-Christophe Jonas
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, Avenue Hippocrate 55 (B1.55.06), B-1200 Brussels, Belgium.
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Santo-Domingo J, Dayon L, Wiederkehr A. Protein Lysine Acetylation: Grease or Sand in the Gears of β-Cell Mitochondria? J Mol Biol 2019; 432:1446-1460. [PMID: 31628953 DOI: 10.1016/j.jmb.2019.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 02/06/2023]
Abstract
Mitochondria carry out many essential functions in metabolism. A central task is the oxidation of nutrients and the generation of ATP by oxidative phosphorylation. Mitochondrial metabolism needs to be tightly regulated for the cell to respond to changes in ATP demand and nutrient supply. Here, we review how protein lysine acetylation contributes to the regulation of mitochondrial metabolism in insulin target tissues and the insulin-secreting pancreatic β-cell. We summarize recent evidence showing that in pancreatic β-cells, lysine acetylation occurs on a large number of proteins involved in metabolism. Furthermore, we give a brief overview of the molecular mechanism that controls lysine acetylation dynamics. We propose that protein lysine acetylation is an important mechanism for the fine-tuning of mitochondrial activity in β-cells during normal physiology. In contrast, nutrient oversupply, oxidative stress, or inhibition of the mitochondrial deacetylase SIRT3 leads to protein lysine hyperacetylation, which impairs mitochondrial function. By perturbing mitochondrial activity in β-cells and insulin target tissues, protein lysine hyperacetylation may contribute to the development of type 2 diabetes.
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Affiliation(s)
- Jaime Santo-Domingo
- Mitochondrial Function, Nestlé Institute of Health Sciences, 1015 Lausanne, Switzerland
| | - Loïc Dayon
- Proteomics, Nestlé Institute of Health Sciences, 1015 Lausanne, Switzerland
| | - Andreas Wiederkehr
- Mitochondrial Function, Nestlé Institute of Health Sciences, 1015 Lausanne, Switzerland.
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40
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Ježek P, Jabůrek M, Plecitá-Hlavatá L. Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes. Antioxid Redox Signal 2019; 31:722-751. [PMID: 30450940 PMCID: PMC6708273 DOI: 10.1089/ars.2018.7656] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022]
Abstract
Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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Newsholme P, Keane KN, Carlessi R, Cruzat V. Oxidative stress pathways in pancreatic β-cells and insulin-sensitive cells and tissues: importance to cell metabolism, function, and dysfunction. Am J Physiol Cell Physiol 2019; 317:C420-C433. [PMID: 31216193 DOI: 10.1152/ajpcell.00141.2019] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It is now accepted that nutrient abundance in the blood, especially glucose, leads to the generation of reactive oxygen species (ROS), ultimately leading to increased oxidative stress in a variety of tissues. In the absence of an appropriate compensatory response from antioxidant mechanisms, the cell, or indeed the tissue, becomes overwhelmed by oxidative stress, leading to the activation of intracellular stress-associated pathways. Activation of the same or similar pathways also appears to play a role in mediating insulin resistance, impaired insulin secretion, and late diabetic complications. The ability of antioxidants to protect against the oxidative stress induced by hyperglycemia and elevated free fatty acid (FFA) levels in vitro suggests a causative role of oxidative stress in mediating the latter clinical conditions. In this review, we describe common biochemical processes associated with oxidative stress driven by hyperglycemia and/or elevated FFA and the resulting clinical outcomes: β-cell dysfunction and peripheral tissue insulin resistance.
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Affiliation(s)
- Philip Newsholme
- School of Pharmacy and Biomedical Sciences, and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Kevin N Keane
- School of Pharmacy and Biomedical Sciences, and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Rodrigo Carlessi
- School of Pharmacy and Biomedical Sciences, and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Vinicius Cruzat
- Faculty of Health, Torrens University Australia, Melbourne, Victoria, Australia
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Potential of Mitochondria-Targeted Antioxidants to Prevent Oxidative Stress in Pancreatic β-cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:1826303. [PMID: 31249641 PMCID: PMC6556329 DOI: 10.1155/2019/1826303] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/02/2019] [Accepted: 04/10/2019] [Indexed: 12/12/2022]
Abstract
Pancreatic β-cells are vulnerable to oxidative stress due to their low content of redox buffers, such as glutathione, but possess a rich content of thioredoxin, peroxiredoxin, and other proteins capable of redox relay, transferring redox signaling. Consequently, it may be predicted that cytosolic antioxidants could interfere with the cytosolic redox signaling and should not be recommended for any potential therapy. In contrast, mitochondrial matrix-targeted antioxidants could prevent the primary oxidative stress arising from the primary superoxide sources within the mitochondrial matrix, such as at the flavin (IF) and ubiquinone (IQ) sites of superoxide formation within respiratory chain complex I and the outer ubiquinone site (IIIQ) of complex III. Therefore, using time-resolved confocal fluorescence monitoring with MitoSOX Red, we investigated various effects of mitochondria-targeted antioxidants in model pancreatic β-cells (insulinoma INS-1E cells) and pancreatic islets. Both SkQ1 (a mitochondria-targeted plastoquinone) and a suppressor of complex III site Q electron leak (S3QEL) prevented superoxide production released to the mitochondrial matrix in INS-1E cells with stimulatory glucose, where SkQ1 also exhibited an antioxidant role for UCP2-silenced cells. SkQ1 acted similarly at nonstimulatory glucose but not in UCP2-silenced cells. Thus, UCP2 can facilitate the antioxidant mechanism based on SkQ1+ fatty acid anion− pairing. The elevated superoxide formation induced by antimycin A was largely prevented by S3QEL, and that induced by rotenone was decreased by SkQ1 and S3QEL and slightly by S1QEL, acting at complex I site Q. Similar results were obtained with the MitoB probe, for the LC-MS-based assessment of the 4 hr accumulation of reactive oxygen species within the mitochondrial matrix but for isolated pancreatic islets. For 2 hr INS-1E incubations, some samples were influenced by the cell death during the experiment. Due to the frequent dependency of antioxidant effects on metabolic modes, we suggest a potential use of mitochondria-targeted antioxidants for the treatment of prediabetic states after cautious nutrition-controlled tests. Their targeted delivery might eventually attenuate the vicious spiral leading to type 2 diabetes.
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Deglasse JP, Roma LP, Pastor-Flores D, Gilon P, Dick TP, Jonas JC. Glucose Acutely Reduces Cytosolic and Mitochondrial H 2O 2 in Rat Pancreatic Beta Cells. Antioxid Redox Signal 2019; 30:297-313. [PMID: 29756464 DOI: 10.1089/ars.2017.7287] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Aims: Whether H2O2 contributes to the glucose-dependent stimulation of insulin secretion (GSIS) by pancreatic β cells is highly controversial. We used two H2O2-sensitive probes, roGFP2-Orp1 (reduction/oxidation-sensitive enhanced green fluorescent protein fused to oxidant receptor peroxidase 1) and HyPer (hydrogen peroxide sensor) with its pH-control SypHer, to test the acute effects of glucose, monomethyl succinate, leucine with glutamine, and α-ketoisocaproate on β cell cytosolic and mitochondrial H2O2 concentrations. We then tested the effects of low H2O2 and menadione concentrations on insulin secretion. Results: RoGFP2-Orp1 was more sensitive than HyPer to H2O2 (response at 2-5 vs. 10 μM) and less pH-sensitive. Under control conditions, stimulation with glucose reduced mitochondrial roGFP2-Orp1 oxidation without affecting cytosolic roGFP2-Orp1 and HyPer fluorescence ratios, except for the pH-dependent effects on HyPer. However, stimulation with glucose decreased the oxidation of both cytosolic probes by 15 μM exogenous H2O2. The glucose effects were not affected by overexpression of catalase, mitochondrial catalase, or superoxide dismutase 1 and 2. They followed the increase in NAD(P)H autofluorescence, were maximal at 5 mM glucose in the cytosol and 10 mM glucose in the mitochondria, and were partly mimicked by the other nutrients. Exogenous H2O2 (1-15 μM) did not affect insulin secretion. By contrast, menadione (1-5 μM) did not increase basal insulin secretion but reduced the stimulation of insulin secretion by 20 mM glucose. Innovation: Subcellular changes in β cell H2O2 levels are better monitored with roGFP2-Orp1 than HyPer/SypHer. Nutrients acutely lower mitochondrial H2O2 levels in β cells and promote degradation of exogenously supplied H2O2 in both cytosolic and mitochondrial compartments. Conclusion: The GSIS occurs independently of a detectable increase in β cell cytosolic or mitochondrial H2O2 levels.
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Affiliation(s)
- Jean-Philippe Deglasse
- 1 Université catholique de Louvain, Institute of experimental and clinical research , Pole of endocrinology, diabetes and nutrition, Brussels, Belgium
| | - Leticia Prates Roma
- 2 Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ) , Heidelberg, Germany .,3 Department of Biophysics, Center for Human and Molecular Biology, Saarland University , Homburg, Germany
| | - Daniel Pastor-Flores
- 2 Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ) , Heidelberg, Germany
| | - Patrick Gilon
- 1 Université catholique de Louvain, Institute of experimental and clinical research , Pole of endocrinology, diabetes and nutrition, Brussels, Belgium
| | - Tobias P Dick
- 2 Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ) , Heidelberg, Germany
| | - Jean-Christophe Jonas
- 1 Université catholique de Louvain, Institute of experimental and clinical research , Pole of endocrinology, diabetes and nutrition, Brussels, Belgium
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Cataldo Bascuñan LR, Lyons C, Bennet H, Artner I, Fex M. Serotonergic regulation of insulin secretion. Acta Physiol (Oxf) 2019; 225:e13101. [PMID: 29791774 DOI: 10.1111/apha.13101] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 12/13/2022]
Abstract
The exact physiological role for the monoamine serotonin (5-HT) in modulation of insulin secretion is yet to be fully understood. Although the presence of this monoamine in islets of Langerhans is well established, it is only with recent advances that the complex signalling network in islets involving 5-HT is being unravelled. With more than fourteen different 5-HT receptors expressed in human islets and receptor-independent mechanisms in insulin-producing β-cells, our understanding of 5-HT's regulation of insulin secretion is increasing. It is now widely accepted that failure of the pancreatic β-cell to release sufficient amounts of insulin is the main cause of type 2 diabetes (T2D), an ongoing global epidemic. In this context, 5-HT signalling may be of importance. In fact, 5-HT may serve an essential role in regulating the release of insulin and glucagon, the two main hormones that control glucose and lipid homoeostasis. In this review, we will discuss past and current understanding of 5-HT's role in the endocrine pancreas.
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Affiliation(s)
- L. R. Cataldo Bascuñan
- Endocrine Cell Differentiation and Function Group; Stem Cell Centre; Lund University; Lund Sweden
| | - C. Lyons
- Department of Clinical Sciences in Malmö; Unit of Molecular Metabolism; Lund University Diabetes Centre; Lund University; Malmö Sweden
- Clinical Research Center; Lund University; Malmö Sweden
- Malmö University Hospital; Lund University; Malmö Sweden
| | - H. Bennet
- Department of Clinical Sciences in Malmö; Unit of Molecular Metabolism; Lund University Diabetes Centre; Lund University; Malmö Sweden
- Clinical Research Center; Lund University; Malmö Sweden
- Malmö University Hospital; Lund University; Malmö Sweden
| | - I. Artner
- Endocrine Cell Differentiation and Function Group; Stem Cell Centre; Lund University; Lund Sweden
| | - M. Fex
- Department of Clinical Sciences in Malmö; Unit of Molecular Metabolism; Lund University Diabetes Centre; Lund University; Malmö Sweden
- Clinical Research Center; Lund University; Malmö Sweden
- Malmö University Hospital; Lund University; Malmö Sweden
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Brinkrolf C, Henke NA, Ochel L, Pucker B, Kruse O, Lutter P. Modeling and Simulating the Aerobic Carbon Metabolism of a Green Microalga Using Petri Nets and New Concepts of VANESA. J Integr Bioinform 2018; 15:/j/jib.2018.15.issue-3/jib-2018-0018/jib-2018-0018.xml. [PMID: 30218605 PMCID: PMC6340121 DOI: 10.1515/jib-2018-0018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 08/16/2018] [Indexed: 12/21/2022] Open
Abstract
In this work we present new concepts of VANESA, a tool for modeling and simulation in systems biology. We provide a convenient way to handle mathematical expressions and take physical units into account. Simulation and result management has been improved, and syntax and consistency checks, based on physical units, reduce modeling errors. As a proof of concept, essential components of the aerobic carbon metabolism of the green microalga Chlamydomonas reinhardtii are modeled and simulated. The modeling process is based on xHPN Petri net formalism and simulation is performed with OpenModelica, a powerful environment and compiler for Modelica. VANESA, as well as OpenModelica, is open source, free-of-charge for non-commercial use, and is available at: http://agbi.techfak.uni-bielefeld.de/vanesa.
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Affiliation(s)
- Christoph Brinkrolf
- Bielefeld University, Faculty of Technology, Bioinformatics Department, Bielefeld, Germany
| | - Nadja A Henke
- Bielefeld University, Faculty of Biology and CeBiTec, Genetics of Prokaryotes, Bielefeld, Germany
| | - Lennart Ochel
- Bielefeld University, Faculty of Technology, Bioinformatics Department, Bielefeld, Germany.,Linköping University, Department of Computer and Information Science, Linköping, Sweden
| | - Boas Pucker
- Bielefeld University, Faculty of Biology and CeBiTec, Genome Research, Bielefeld, Germany.,University of Cambridge, Department of PlantSciences, Evolution and Diversity, Cambridge, UK
| | - Olaf Kruse
- Bielefeld University, Faculty of Biology and CeBiTec, Algae Biotechnology and Bioenergy, Bielefeld, Germany
| | - Petra Lutter
- Bielefeld University, Faculty of Biology and CeBiTec, Proteome and Metabolome Research, Bielefeld, Germany
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Oxidative stress decreases the redox ratio and folate content in the gut microbe, Enterococcus durans (MTCC 3031). Sci Rep 2018; 8:12138. [PMID: 30108274 PMCID: PMC6092354 DOI: 10.1038/s41598-018-30691-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 08/02/2018] [Indexed: 12/24/2022] Open
Abstract
Gut microbiome plays an important role in determining the effectiveness of cancer therapy. The composition of the microbiome is crucial to maintain good digestive health in the host, and to prevent and treat colorectal cancers. Most cancer therapies employ oxidative stress, which disturbs the redox status of the cell, and consequently affect growth, reductive biosynthesis and cell death. Therefore, oxidative stress can undesirably affect the gut microbiome. Hence, it is important to understand the impact of oxidative stress on gut bacteria to devise effective treatment strategies. The current study induces oxidative stress in the model gut bacterium Enterococcus durans (MTCC 3031) with menadione and H2O2. Oxidative stress considerably decreased the redox ratio (NADPH/NADP), an indicator of the redox status, by 55% (menadione) and 28% (H2O2). In addition, an oxidative stress induced decrease in redox ratio decreased folate synthesis by the bacteria, which is an undesirable consequence for the host, since folate deficiency can induce colorectal cancer. Further, oxidative stress considerably decreased growth and the biomass density by 61% (menadione) and 21% (H2O2). Thus, maintenance of the cellular redox status and management of oxidative stress in the gut microbiome may be crucial to the effectiveness of cancer treatment strategies.
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Mice harboring the human SLC30A8 R138X loss-of-function mutation have increased insulin secretory capacity. Proc Natl Acad Sci U S A 2018; 115:E7642-E7649. [PMID: 30038024 PMCID: PMC6094147 DOI: 10.1073/pnas.1721418115] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
SLC30A8 encodes a zinc transporter that is primarily expressed in the pancreatic islets of Langerhans. In β-cells it transports zinc into insulin-containing secretory granules. Loss-of-function (LOF) mutations in SLC30A8 protect against type 2 diabetes in humans. In this study, we generated a knockin mouse model carrying one of the most common human LOF mutations for SLC30A8, R138X. The R138X mice had normal body weight, glucose tolerance, and pancreatic β-cell mass. Interestingly, in hyperglycemic conditions induced by the insulin receptor antagonist S961, the R138X mice showed a 50% increase in insulin secretion. This effect was not associated with enhanced β-cell proliferation or mass. Our data suggest that the SLC30A8 R138X LOF mutation may exert beneficial effects on glucose metabolism by increasing the capacity of β-cells to secrete insulin under hyperglycemic conditions.
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Fatty Acid-Stimulated Insulin Secretion vs. Lipotoxicity. Molecules 2018; 23:molecules23061483. [PMID: 29921789 PMCID: PMC6100479 DOI: 10.3390/molecules23061483] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 12/29/2022] Open
Abstract
Fatty acid (FA)-stimulated insulin secretion (FASIS) is reviewed here in contrast to type 2 diabetes etiology, resulting from FA overload, oxidative stress, intermediate hyperinsulinemia, and inflammation, all converging into insulin resistance. Focusing on pancreatic islet β-cells, we compare the physiological FA roles with the pathological ones. Considering FAs not as mere amplifiers of glucose-stimulated insulin secretion (GSIS), but as parallel insulin granule exocytosis inductors, partly independent of the KATP channel closure, we describe the FA initiating roles in the prediabetic state that is induced by retardations in the glycerol-3-phosphate (glucose)-promoted glycerol/FA cycle and by the impaired GPR40/FFA1 (free FA1) receptor pathway, specifically in its amplification by the redox-activated mitochondrial phospholipase, iPLA2γ. Also, excessive dietary FAs stimulate intestine enterocyte incretin secretion, further elevating GSIS, even at low glucose levels, thus contributing to diabetic hyperinsulinemia. With overnutrition and obesity, the FA overload causes impaired GSIS by metabolic dysbalance, paralleled by oxidative and metabolic stress, endoplasmic reticulum stress and numerous pro-apoptotic signaling, all leading to decreased β-cell survival. Lipotoxicity is exerted by saturated FAs, whereas ω-3 polyunsaturated FAs frequently exert antilipotoxic effects. FA-facilitated inflammation upon the recruitment of excess M1 macrophages into islets (over resolving M2 type), amplified by cytokine and chemokine secretion by β-cells, leads to an inevitable failure of pancreatic β-cells.
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Gerencser AA. Metabolic activation-driven mitochondrial hyperpolarization predicts insulin secretion in human pancreatic beta-cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:817-828. [PMID: 29886047 DOI: 10.1016/j.bbabio.2018.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/18/2018] [Accepted: 06/05/2018] [Indexed: 12/31/2022]
Abstract
Mitochondrial metabolism plays a central role in insulin secretion in pancreatic beta-cells. Generation of protonmotive force and ATP synthesis from glucose-originated pyruvate are critical steps in the canonical pathway of glucose-stimulated insulin secretion. Mitochondrial metabolism is intertwined with pathways that are thought to amplify insulin secretion with mechanisms distinct from the canonical pathway, and the relative importance of these two pathways is controversial. Here I show that glucose-induced mitochondrial membrane potential (MMP) hyperpolarization is necessary for, and predicts, the rate of insulin secretion in primary cultured human beta-cells. When glucose concentration is elevated, increased metabolism results in a substantial MMP hyperpolarization, as well as in increased rates of ATP synthesis and turnover marked by faster cell respiration. Using modular kinetic analysis I explored what properties of cellular energy metabolism enable a large glucose-induced change in MMP in human beta-cells. I found that an ATP-dependent pathway activates glucose or substrate oxidation, acting as a positive feedback in energy metabolism. This activation mechanism is essential for concomitant fast respiration and high MMP, and for a high magnitude glucose-induced MMP hyperpolarization and therefore for insulin secretion.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Image Analyst Software, 43 Nova Lane, Novato, CA 94945, United States.
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Wu W, Liu F, Wu K, Chen Y, Wu H, Dai G, Zhang W. Lon Peptidase 2, Peroxisomal (LONP2) Contributes to Cervical Carcinogenesis via Oxidative Stress. Med Sci Monit 2018; 24:1310-1320. [PMID: 29502128 PMCID: PMC5846714 DOI: 10.12659/msm.908966] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background Lon protease is responsible for degrading proteins injured by oxidation, and has 2 isoforms, located in mitochondria and peroxisomes. Recent research showed that Lon protease was upregulated in different types of human cancer, but the role of Lon peptidase 2, peroxisomal (LONP2) in cancer is not well understood. It is known, however, that in cancer biology, reduction-oxidation is one of the molecular mechanisms involved in tumorigenesis. Material/Methods Oncomine databases and tissue microarrays, initially using immunohistochemistry, were used to analyze LONP2 expression in cervical cancer. In order to uncover the biologic functions and mechanism(s) underlying LONP2 in cervical tumorigenesis, we downregulated the expression of LONP2 using 2 siRNAs transduced in HeLa and SiHa cells. CCK8 assays were performed to evaluate cell viability. Cell cycle and apoptosis assays were used to determine cell growth. Cell migration and invasion assays were used to study changes in cell migration and invasion capacity. Immunofluorescence and flow cytometry were performed to analyze the changes in ROS production. Results We found that the expression of LONP2 was significantly upregulated in cervical cancer, and there was a significant association with pathology type, pathology grade, and clinical stage, but not with age or lymph node metastasis. Moreover, we demonstrated that knocking down LONP2 in HeLa and SiHa cells reduced cell proliferation, cell cycle, apoptosis, migration, invasion, and oxidative stress levels. Conclusions Our findings suggest that LONP2 promotes cervical tumorigenesis via oxidative stress and may be a potential biomarker and therapeutic target in cervical cancer.
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Affiliation(s)
- Wanrong Wu
- First Department of Gynaecology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland).,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Fulin Liu
- First Department of Gynaecology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Kejia Wu
- Department of Gynaecology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Yurou Chen
- First Department of Gynaecology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Hanshu Wu
- First Department of Gynaecology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Guo Dai
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Wei Zhang
- First Department of Gynaecology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
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