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Elksnis A, Cen J, Wikström P, Carlsson PO, Welsh N. Pharmacological Inhibition of NOX4 Improves Mitochondrial Function and Survival in Human Beta-Cells. Biomedicines 2021; 9:biomedicines9121865. [PMID: 34944680 PMCID: PMC8698703 DOI: 10.3390/biomedicines9121865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/31/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022] Open
Abstract
Previous studies have reported beneficial effects of NADPH oxidase 4 (NOX4) inhibition on beta-cell survival in vitro and in vivo. The mechanisms by which NOX4 inhibition protects insulin producing cells are, however, not known. The aim of the present study was to investigate the effects of a pharmacological NOX4 inhibitor (GLX7013114) on human islet and EndoC-βH1 cell mitochondrial function, and to correlate such effects with survival in islets of different size, activity, and glucose-stimulated insulin release responsiveness. We found that maximal oxygen consumption rates, but not the rates of acidification and proton leak, were increased in islets after acute NOX4 inhibition. In EndoC-βH1 cells, NOX4 inhibition increased the mitochondrial membrane potential, as estimated by JC-1 fluorescence; mitochondrial reactive oxygen species (ROS) production, as estimated by MitoSOX fluorescence; and the ATP/ADP ratio, as assessed by a bioluminescent assay. Moreover, the insulin release from EndoC-βH1 cells at a high glucose concentration increased with NOX4 inhibition. These findings were paralleled by NOX4 inhibition-induced protection against human islet cell death when challenged with high glucose and sodium palmitate. The NOX4 inhibitor protected equally well islets of different size, activity, and glucose responsiveness. We conclude that pharmacological alleviation of NOX4-induced inhibition of beta-cell mitochondria leads to increased, and not decreased, mitochondrial ROS, and this was associated with protection against cell death occurring in different types of heterogeneous islets. Thus, NOX4 inhibition or modulation may be a therapeutic strategy in type 2 diabetes that targets all types of islets.
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Affiliation(s)
- Andris Elksnis
- Science for Life Laboratory, Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden; (A.E.); (J.C.); (P.-O.C.)
| | - Jing Cen
- Science for Life Laboratory, Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden; (A.E.); (J.C.); (P.-O.C.)
| | - Per Wikström
- Glucox Biotech AB, Frälsegårdsvägen 8, SE-179 97 Färentuna, Sweden;
| | - Per-Ola Carlsson
- Science for Life Laboratory, Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden; (A.E.); (J.C.); (P.-O.C.)
- Department of Medical Sciences, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Nils Welsh
- Science for Life Laboratory, Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden; (A.E.); (J.C.); (P.-O.C.)
- Correspondence: ; Tel.: +46-184-714-212
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Marmentini C, Branco RCS, Boschero AC, Kurauti MA. Islet amyloid toxicity: From genesis to counteracting mechanisms. J Cell Physiol 2021; 237:1119-1142. [PMID: 34636428 DOI: 10.1002/jcp.30600] [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: 03/21/2021] [Revised: 09/09/2021] [Accepted: 10/01/2021] [Indexed: 11/11/2022]
Abstract
Islet amyloid polypeptide (IAPP or amylin) is a hormone co-secreted with insulin by pancreatic β-cells and is the major component of islet amyloid. Islet amyloid is found in the pancreas of patients with type 2 diabetes (T2D) and may be involved in β-cell dysfunction and death, observed in this disease. Thus, investigating the aspects related to amyloid formation is relevant to the development of strategies towards β-cell protection. In this sense, IAPP misprocessing, IAPP overproduction, and disturbances in intra- and extracellular environments seem to be decisive for IAPP to form islet amyloid. Islet amyloid toxicity in β-cells may be triggered in intra- and/or extracellular sites by membrane damage, endoplasmic reticulum stress, autophagy disruption, mitochondrial dysfunction, inflammation, and apoptosis. Importantly, different approaches have been suggested to prevent islet amyloid cytotoxicity, from inhibition of IAPP aggregation to attenuation of cell death mechanisms. Such approaches have improved β-cell function and prevented the development of hyperglycemia in animals. Therefore, counteracting islet amyloid may be a promising therapy for T2D treatment.
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Affiliation(s)
- Carine Marmentini
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Renato C S Branco
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Antonio C Boschero
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Mirian A Kurauti
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil.,Department of Physiological Sciences, Biological Sciences Center, State University of Maringa (UEM), Maringa, Brazil
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Wang B, Queenan BN, Wang S, Nilsson KPR, Bazan GC. Precisely Defined Conjugated Oligoelectrolytes for Biosensing and Therapeutics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806701. [PMID: 30698856 DOI: 10.1002/adma.201806701] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/25/2018] [Indexed: 06/09/2023]
Abstract
Conjugated oligoelectrolytes (COEs) are a relatively new class of synthetic organic molecules with, as of yet, untapped potential for use in organic optoelectronic devices and bioelectronic systems. COEs also offer a novel molecular approach to biosensing, bioimaging, and disease therapy. Substantial progress has been made in the past decade at the intersection of chemistry, materials science, and the biological sciences developing COEs and their polymer analogues, namely, conjugated polyelectrolytes (CPEs), into synthetic systems with biological and biomedical utility. CPEs have traditionally attracted more attention in arenas of sensing, imaging, and therapy. However, the precisely defined molecular structures and interactions of COEs offer potential key advantages over CPEs, including higher reliability and fluorescence quantum efficiency, larger diversity of subcellular targeting strategies, and improved selectivity to biomolecules. Here, the unique-and sometimes overlooked-properties of COEs are discussed and the noticeable progress in their use for biological sensing, imaging, and therapy is reviewed.
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Affiliation(s)
- Bing Wang
- Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Bridget N Queenan
- Department of Mechanical Engineering, Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA
| | - Shu Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - K Peter R Nilsson
- Division of Chemistry, Department of Physics, Chemistry and Biology, Linköping University, Linköping, SE, -581 83, Sweden
| | - Guillermo C Bazan
- Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
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Chen YC, Taylor AJ, Verchere CB. Islet prohormone processing in health and disease. Diabetes Obes Metab 2018; 20 Suppl 2:64-76. [PMID: 30230179 DOI: 10.1111/dom.13401] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022]
Abstract
Biosynthesis of peptide hormones by pancreatic islet endocrine cells is a tightly orchestrated process that is critical for metabolic homeostasis. Like neuroendocrine peptides, insulin and other islet hormones are first synthesized as larger precursor molecules that are processed to their mature secreted products through a series of proteolytic cleavages, mediated by the prohormone convertases Pc1/3 and Pc2, and carboxypeptidase E. Additional posttranslational modifications including C-terminal amidation of the β-cell peptide islet amyloid polypeptide (IAPP) by peptidyl-glycine α-amidating monooxygenase (Pam) may also occur. Genome-wide association studies (GWAS) have showed genetic linkage of these processing enzymes to obesity, β-cell dysfunction, and type 2 diabetes (T2D), pointing to their important roles in metabolism and blood glucose regulation. In both type 1 diabetes (T1D) and T2D, and in the face of metabolic or inflammatory stresses, islet prohormone processing may become impaired; indeed elevated proinsulin:insulin (PI:I) ratios are a hallmark of the β-cell dysfunction in T2D. Recent studies suggest that genetic or acquired defects in proIAPP processing may lead to the production and secretion of incompletely processed forms of proIAPP that could contribute to T2D pathogenesis, and additionally that impaired processing of both PI and proIAPP may be characteristic of β-cell dysfunction in T1D. In islet α-cells, the prohormone proglucagon is normally processed to bioactive glucagon by Pc2 but may express Pc1/3 under certain conditions leading to production of GLP-1(7-36NH2 ). A better understanding of how β-cell processing of PI and proIAPP, as well as α-cell processing of proglucagon, are impacted by genetic susceptibility and in the face of diabetogenic stresses, may lead to new therapeutic approaches for improving islet function in diabetes.
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Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
| | - Austin J Taylor
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
| | - C Bruce Verchere
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
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