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Holendová B, Šalovská B, Benáková Š, Plecitá-Hlavatá L. Beyond glucose: The crucial role of redox signaling in β-cell metabolic adaptation. Metabolism 2024:156027. [PMID: 39260557 DOI: 10.1016/j.metabol.2024.156027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 08/23/2024] [Accepted: 09/06/2024] [Indexed: 09/13/2024]
Abstract
OBJECTIVE Redox signaling mediated by reversible oxidative cysteine thiol modifications is crucial for driving cellular adaptation to dynamic environmental changes, maintaining homeostasis, and ensuring proper function. This is particularly critical in pancreatic β-cells, which are highly metabolically active and play a specialized role in whole organism glucose homeostasis. Glucose stimulation in β-cells triggers signals leading to insulin secretion, including changes in ATP/ADP ratio and intracellular calcium levels. Additionally, lipid metabolism and reactive oxygen species (ROS) signaling are essential for β-cell function and health. METHODS We employed IodoTMT isobaric labeling combined with tandem mass spectrometry to elucidate redox signaling pathways in pancreatic β-cells. RESULTS Glucose stimulation significantly increases ROS levels in β-cells, leading to targeted reversible oxidation of proteins involved in key metabolic pathways such as glycolysis, the tricarboxylic acid (TCA) cycle, pyruvate metabolism, oxidative phosphorylation, protein processing in the endoplasmic reticulum (ER), and insulin secretion. Furthermore, the glucose-induced increase in reversible cysteine oxidation correlates with the presence of other post-translational modifications, including acetylation and phosphorylation. CONCLUSIONS Proper functioning of pancreatic β-cell metabolism relies on fine-tuned regulation, achieved through a sophisticated system of diverse post-translational modifications that modulate protein functions. Our findings demonstrate that glucose induces the production of ROS in pancreatic β-cells, leading to targeted reversible oxidative modifications of proteins. Furthermore, protein activity is modulated by acetylation and phosphorylation, highlighting the complexity of the regulatory mechanisms in β-cell function.
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Affiliation(s)
- Blanka Holendová
- Laboratory of Pancreatic Islet Research, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Barbora Šalovská
- Department of Genome Integrity, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic; Yale Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, USA
| | - Štěpánka Benáková
- Laboratory of Pancreatic Islet Research, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Laboratory of Pancreatic Islet Research, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
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2
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Jabůrek M, Klöppel E, Průchová P, Mozheitova O, Tauber J, Engstová H, Ježek P. Mitochondria to plasma membrane redox signaling is essential for fatty acid β-oxidation-driven insulin secretion. Redox Biol 2024; 75:103283. [PMID: 39067330 PMCID: PMC11332078 DOI: 10.1016/j.redox.2024.103283] [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: 07/17/2024] [Revised: 07/22/2024] [Accepted: 07/22/2024] [Indexed: 07/30/2024] Open
Abstract
We asked whether acute redox signaling from mitochondria exists concomitantly to fatty acid- (FA-) stimulated insulin secretion (FASIS) at low glucose by pancreatic β-cells. We show that FA β-oxidation produces superoxide/H2O2, providing: i) mitochondria-to-plasma-membrane redox signaling, closing KATP-channels synergically with elevated ATP (substituting NADPH-oxidase-4-mediated H2O2-signaling upon glucose-stimulated insulin secretion); ii) activation of redox-sensitive phospholipase iPLA2γ/PNPLA8, cleaving mitochondrial FAs, enabling metabotropic GPR40 receptors to amplify insulin secretion (IS). At fasting glucose, palmitic acid stimulated IS in wt mice; palmitic, stearic, lauric, oleic, linoleic, and hexanoic acids also in perifused pancreatic islets (PIs), with suppressed 1st phases in iPLA2γ/PNPLA8-knockout mice/PIs. Extracellular/cytosolic H2O2-monitoring indicated knockout-independent redox signals, blocked by mitochondrial antioxidant SkQ1, etomoxir, CPT1 silencing, and catalase overexpression, all inhibiting FASIS, keeping ATP-sensitive K+-channels open, and diminishing cytosolic [Ca2+]-oscillations. FASIS in mice was a postprandially delayed physiological event. Redox signals of FA β-oxidation are thus documented, reaching the plasma membrane, essentially co-stimulating IS.
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Affiliation(s)
- Martin Jabůrek
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Eduardo Klöppel
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Pavla Průchová
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Oleksandra Mozheitova
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Jan Tauber
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Hana Engstová
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic.
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3
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Marhl M. What do stimulated beta cells have in common with cancer cells? Biosystems 2024; 242:105257. [PMID: 38876357 DOI: 10.1016/j.biosystems.2024.105257] [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: 03/26/2024] [Revised: 06/11/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
This study investigates the metabolic parallels between stimulated pancreatic beta cells and cancer cells, focusing on glucose and glutamine metabolism. Addressing the significant public health challenges of Type 2 Diabetes (T2D) and cancer, we aim to deepen our understanding of the mechanisms driving insulin secretion and cellular proliferation. Our analysis of anaplerotic cycles and the role of NADPH in biosynthesis elucidates their vital functions in both processes. Additionally, we point out that both cell types share an antioxidative response mediated by the Nrf2 signaling pathway, glutathione synthesis, and UCP2 upregulation. Notably, UCP2 facilitates the transfer of C4 metabolites, enhancing reductive TCA cycle metabolism. Furthermore, we observe that hypoxic responses are transient in beta cells post-stimulation but persistent in cancer cells. By synthesizing these insights, the research may suggest novel therapeutic targets for T2D, highlighting the shared metabolic strategies of stimulated beta cells and cancer cells. This comparative analysis not only illuminates the metabolic complexity of these conditions but also emphasizes the crucial role of metabolic pathways in cell function and survival, offering fresh perspectives for tackling T2D and cancer challenges.
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Affiliation(s)
- Marko Marhl
- Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000, Maribor, Slovenia; Faculty of Education, University of Maribor, Koroška cesta 160, 2000, Maribor, Slovenia; Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000, Maribor, Slovenia.
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Grubelnik V, Zmazek J, Gosak M, Marhl M. The role of anaplerotic metabolism of glucose and glutamine in insulin secretion: A model approach. Biophys Chem 2024; 311:107270. [PMID: 38833963 DOI: 10.1016/j.bpc.2024.107270] [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: 01/31/2024] [Revised: 05/22/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
We propose a detailed computational beta cell model that emphasizes the role of anaplerotic metabolism under glucose and glucose-glutamine stimulation. This model goes beyond the traditional focus on mitochondrial oxidative phosphorylation and ATP-sensitive K+ channels, highlighting the predominant generation of ATP from phosphoenolpyruvate in the vicinity of KATP channels. It also underlines the modulatory role of H2O2 as a signaling molecule in the first phase of glucose-stimulated insulin secretion. In the second phase, the model emphasizes the critical role of anaplerotic pathways, activated by glucose stimulation via pyruvate carboxylase and by glutamine via glutamate dehydrogenase. It particularly focuses on the production of NADPH and glutamate as key enhancers of insulin secretion. The predictions of the model are consistent with empirical data, highlighting the complex interplay of metabolic pathways and emphasizing the primary role of glucose and the facilitating role of glutamine in insulin secretion. By delineating these crucial metabolic pathways, the model provides valuable insights into potential therapeutic targets for diabetes.
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Affiliation(s)
- Vladimir Grubelnik
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroška cesta 46, 2000 Maribor, Slovenia
| | - Jan Zmazek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
| | - Marko Gosak
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Alma Mater Europaea ECM, Slovenska ulica 17, 2000 Maribor, Slovenia
| | - Marko Marhl
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Faculty of Education, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia.
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Pei X, Wang Z, He W, Li S, Chen X, Fan Z, Lan Y, Yuan L, Xu P. ER-tethered RNA-binding protein controls NADPH oxidase translation for hydrogen peroxide homeostasis. Redox Biol 2024; 71:103126. [PMID: 38503217 PMCID: PMC10963860 DOI: 10.1016/j.redox.2024.103126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/04/2024] [Accepted: 03/14/2024] [Indexed: 03/21/2024] Open
Abstract
Hydrogen peroxide (H2O2) functions as a signaling molecule in diverse cellular processes. While cells have evolved the capability to detect and manage changes in H2O2 levels, the mechanisms regulating key H2O2-producing enzymes to maintain optimal levels, especially in pancreatic beta cells with notably weak antioxidative defense, remain unclear. We found that the protein EI24 responds to changes in H2O2 concentration and regulates the production of H2O2 by controlling the translation of NOX4, an enzyme that is constitutively active, achieved by recruiting an RNA-binding protein, RTRAF, to the 3'-UTR of Nox4. Depleting EI24 results in RTRAF relocating into the nucleus, releasing the brake on NOX4 translation. The excessive production of H2O2 by liberated NOX4 further suppresses the translation of the key transcription factor MafA, ultimately preventing its binding to the Ins2 gene promoter and subsequent transcription of insulin. Treatment with a specific NOX4 inhibitor or the antioxidant NAC reversed these effects and alleviated the diabetic symptoms in beta-cell specific Ei24-KO mice. This study revealed a new mechanism through which cells regulate oxidative stress at the translational level, involving an ER-tethered RNA-binding protein that controls the expression of the key H2O2-producing enzyme NOX4.
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Affiliation(s)
- Xintong Pei
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhe Wang
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenting He
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shunqin Li
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaowei Chen
- Center for High Throughput Sequencing, Core Facility for Protein Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhen Fan
- Center for High Throughput Sequencing, Core Facility for Protein Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yongguang Lan
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lin Yuan
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Pingyong Xu
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China; Department of Clinical Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
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Holendová B, Benáková Š, Křivonosková M, Pavluch V, Tauber J, Gabrielová E, Ježek P, Plecitá-Hlavatá L. NADPH oxidase 4 in mouse β cells participates in inflammation on chronic nutrient overload. Obesity (Silver Spring) 2024; 32:339-351. [PMID: 38086768 DOI: 10.1002/oby.23956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 09/13/2023] [Accepted: 10/06/2023] [Indexed: 01/16/2024]
Abstract
OBJECTIVE By exposing mice carrying a deletion of NADPH oxidase isoform 4, NOX4, specifically in pancreatic β cells (βNOX4-/-) to nutrient excess stimulated by a high-fat diet (HFD), this study aimed to elucidate the role of β-cell redox status in the development of meta-inflammation within the diabetic phenotype. METHODS The authors performed basic phenotyping of βNOX4-/- mice on HFD involving insulin and glycemic analyses, histochemistry of adipocytes, indirect calorimetry, and cytokine analyses. To characterize local inflammation, the study used caspase-1 activity assay, interleukin-1β immunochemistry, and real-time polymerase chain reaction during coculturing of β cells with macrophages. RESULTS The phenotype of βNOX4-/- mice on HFD was not associated with hyperinsulinemia and hyperglycemia but showed accumulation of excessive lipids in epididymal fat and β cells. Surprisingly, mice showed significantly reduced systemic inflammation. Decreased interleukin-1β protein levels and downregulated NLRP3-inflammasome activity were observed on chronic glucose overload in βNOX4-/- isolated islets and NOX4-silenced INS1-E cells resulting in attenuated proinflammatory polarization of macrophages/monocytes in vitro and in situ and reduced local islet inflammation. CONCLUSIONS Experimental evidence suggests that NOX4 pro-oxidant activity in β cells is involved in NLRP3-inflammasome activation during chronic nutrient overload and participates in local inflammatory signaling and perhaps toward peripheral tissues, contributing to a diabetic inflammatory phenotype.
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Affiliation(s)
- Blanka Holendová
- Laboratory of Pancreatic Islet Research, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Štěpánka Benáková
- Laboratory of Pancreatic Islet Research, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Monika Křivonosková
- Laboratory of Pancreatic Islet Research, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Vojtěch Pavluch
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Tauber
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Eva Gabrielová
- Department of Medical Chemistry and Biochemistry, Palacký University, Olomouc, Czech Republic
| | - Petr Ježek
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Laboratory of Pancreatic Islet Research, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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7
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Veluthakal R, Esparza D, Hoolachan JM, Balakrishnan R, Ahn M, Oh E, Jayasena CS, Thurmond DC. Mitochondrial Dysfunction, Oxidative Stress, and Inter-Organ Miscommunications in T2D Progression. Int J Mol Sci 2024; 25:1504. [PMID: 38338783 PMCID: PMC10855860 DOI: 10.3390/ijms25031504] [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: 12/22/2023] [Revised: 01/15/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024] Open
Abstract
Type 2 diabetes (T2D) is a heterogenous disease, and conventionally, peripheral insulin resistance (IR) was thought to precede islet β-cell dysfunction, promoting progression from prediabetes to T2D. New evidence suggests that T2D-lean individuals experience early β-cell dysfunction without significant IR. Regardless of the primary event (i.e., IR vs. β-cell dysfunction) that contributes to dysglycemia, significant early-onset oxidative damage and mitochondrial dysfunction in multiple metabolic tissues may be a driver of T2D onset and progression. Oxidative stress, defined as the generation of reactive oxygen species (ROS), is mediated by hyperglycemia alone or in combination with lipids. Physiological oxidative stress promotes inter-tissue communication, while pathological oxidative stress promotes inter-tissue mis-communication, and new evidence suggests that this is mediated via extracellular vesicles (EVs), including mitochondria containing EVs. Under metabolic-related stress conditions, EV-mediated cross-talk between β-cells and skeletal muscle likely trigger mitochondrial anomalies leading to prediabetes and T2D. This article reviews the underlying molecular mechanisms in ROS-related pathogenesis of prediabetes, including mitophagy and mitochondrial dynamics due to oxidative stress. Further, this review will describe the potential of various therapeutic avenues for attenuating oxidative damage, reversing prediabetes and preventing progression to T2D.
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Affiliation(s)
- Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes & Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E. Duarte Rd, Duarte, CA 91010, USA; (D.E.); (J.M.H.); (R.B.); (M.A.); (E.O.); (C.S.J.)
| | | | | | | | | | | | | | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes & Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E. Duarte Rd, Duarte, CA 91010, USA; (D.E.); (J.M.H.); (R.B.); (M.A.); (E.O.); (C.S.J.)
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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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9
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Moon DO. NADPH Dynamics: Linking Insulin Resistance and β-Cells Ferroptosis in Diabetes Mellitus. Int J Mol Sci 2023; 25:342. [PMID: 38203517 PMCID: PMC10779351 DOI: 10.3390/ijms25010342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/20/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
This review offers an in-depth exploration of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) in metabolic health. It delves into how NADPH affects insulin secretion, influences insulin resistance, and plays a role in ferroptosis. NADPH, a critical cofactor in cellular antioxidant systems and lipid synthesis, plays a central role in maintaining metabolic homeostasis. In adipocytes and skeletal muscle, NADPH influences the pathophysiology of insulin resistance, a hallmark of metabolic disorders such as type 2 diabetes and obesity. The review explores the mechanisms by which NADPH contributes to or mitigates insulin resistance, including its role in lipid and reactive oxygen species (ROS) metabolism. Parallelly, the paper investigates the dual nature of NADPH in the context of pancreatic β-cell health, particularly in its relation to ferroptosis, an iron-dependent form of programmed cell death. While NADPH's antioxidative properties are crucial for preventing oxidative damage in β-cells, its involvement in lipid metabolism can potentiate ferroptotic pathways under certain pathological conditions. This complex relationship underscores the delicate balance of NADPH homeostasis in pancreatic health and diabetes pathogenesis. By integrating findings from recent studies, this review aims to illuminate the nuanced roles of NADPH in different tissues and its potential as a therapeutic target. Understanding these dynamics offers vital insights into the development of more effective strategies for managing insulin resistance and preserving pancreatic β-cell function, thereby advancing the treatment of metabolic diseases.
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Affiliation(s)
- Dong-Oh Moon
- Department of Biology Education, Daegu University, 201 Daegudae-ro, Gyeongsan-si 38453, Gyeongsangbuk-do, Republic of Korea
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Klotz LO, Carlberg C. Nutrigenomics and redox regulation: Concepts relating to the Special Issue on nutrigenomics. Redox Biol 2023; 68:102920. [PMID: 37839954 PMCID: PMC10624588 DOI: 10.1016/j.redox.2023.102920] [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: 08/17/2023] [Revised: 09/21/2023] [Accepted: 10/03/2023] [Indexed: 10/17/2023] Open
Abstract
During our whole lifespan, from conception to death, the epigenomes of all tissues and cell types of our body integrate signals from the environment. This includes signals derived from our diet and the uptake of macro- and micronutrients. In most cases, this leads only to transient changes, but some effects of this epigenome programming process are persistent and can even be transferred to the next generation. Both epigenetic programming and redox processes are affected by the individual choice of diet and other lifestyle decisions like physical activity. The nutrient-gene communication pathways have adapted during human evolution and are essential for maintaining health. However, when they are maladaptive, such as in long-term obesity, they significantly contribute to diseases like type 2 diabetes and cancer. The field of nutrigenomics investigates nutrition-related signal transduction pathways and their effect on gene expression involving interactions both with the genome and the epigenomes. Several of these diet-(epi)genome interactions and the involved signal transduction cascades are redox-regulated. Examples include the effects of the NAD+/NADH ratio, vitamin C levels and secondary metabolites of dietary molecules from plants on the acetylation and methylation state of the epigenome as well as on gene expression through redox-sensitive pathways via the transcription factors NFE2L2 and FOXO. In this review, we summarize and extend on these topics as well as those discussed in the articles of this Special Issue and take them into the context of redox biology.
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Affiliation(s)
- Lars-Oliver Klotz
- Institute of Nutritional Sciences, Nutrigenomics Section, Friedrich Schiller University Jena, Jena, Germany
| | - Carsten Carlberg
- Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, PL-10-748, Olsztyn, Poland; School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211, Kuopio, Finland.
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11
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Hill CR, Haoci Liu A, McCahon L, Zhong L, Shafaei A, Balmer L, Lewis JR, Hodgson JM, Blekkenhorst LC. S-methyl cysteine sulfoxide and its potential role in human health: a scoping review. Crit Rev Food Sci Nutr 2023:1-14. [PMID: 37819533 DOI: 10.1080/10408398.2023.2267133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Higher intakes of cruciferous and allium vegetables are associated with a lower risk of cardiometabolic-related outcomes in observational studies. Whilst acknowledging the many healthy compounds within these vegetables, animal studies indicate that some of these beneficial effects may be partially mediated by S-methyl cysteine sulfoxide (SMCSO), a sulfur-rich, non-protein, amino acid found almost exclusively within cruciferous and alliums. This scoping review explores evidence for SMCSO, its potential roles in human health and possible mechanistic action. After systematically searching several databases (EMBASE, MEDLINE, SCOPUS, CINAHL Plus Full Text, Agricultural Science), we identified 21 original research articles meeting our inclusion criteria. These were limited primarily to animal and in vitro models, with 14/21 (67%) indicating favorable anti-hyperglycemic, anti-hypercholesterolemic, and antioxidant properties. Potential mechanisms included increased bile acid and sterol excretion, altered glucose- and cholesterol-related enzymes, and improved hepatic and pancreatic β-cell function. Raising antioxidant defenses may help mitigate the oxidative damage observed in these pathologies. Anticancer and antibacterial effects were also explored, along with one steroidogenic study. SMCSO is frequently overlooked as a potential mediator to the benefits of sulfur-rich vegetables. More research into the health benefits of SMCSO, especially for cardiometabolic and inflammatory-based pathology, is warranted. Human studies are especially needed.
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Affiliation(s)
- Caroline R Hill
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
| | - Alex Haoci Liu
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
- Medical School, The University of Western Australia, Perth, Western Australia, Australia
| | - Lyn McCahon
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
| | - Liezhou Zhong
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
| | - Armaghan Shafaei
- Centre for Integrative Metabolomics and Computational Biology, School of Science, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Lois Balmer
- Centre for Precision Health, School of Medical and Health Science, Edith Cowan University, Joondalup, Western Australia, Australia
- Centre for Diabetes Research, Harry Perkins Institute of Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Joshua R Lewis
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
- Medical School, The University of Western Australia, Perth, Western Australia, Australia
- Centre for Kidney Research, Children's Hospital at Westmead School of Public Health, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Jonathan M Hodgson
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
- Medical School, The University of Western Australia, Perth, Western Australia, Australia
| | - Lauren C Blekkenhorst
- Nutrition and Health Innovation Research Institute, School of Medical and Health Science, Edith Cowan University, Royal Perth Hospital Research Foundation, Perth, Western Australia, Australia
- Medical School, The University of Western Australia, Perth, Western Australia, Australia
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12
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Lang AL, Nissanka N, Louzada RA, Tamayo A, Pereira E, Moraes CT, Caicedo A. A Defect in Mitochondrial Complex III but Not in Complexes I or IV Causes Early β-Cell Dysfunction and Hyperglycemia in Mice. Diabetes 2023; 72:1262-1276. [PMID: 37343239 PMCID: PMC10451017 DOI: 10.2337/db22-0728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 06/04/2023] [Indexed: 06/23/2023]
Abstract
Mitochondrial metabolism and oxidative respiration are crucial for pancreatic β-cell function and stimulus secretion coupling. Oxidative phosphorylation (OxPhos) produces ATP and other metabolites that potentiate insulin secretion. However, the contribution of individual OxPhos complexes to β-cell function is unknown. We generated β-cell-specific, inducible OxPhos complex knock-out (KO) mouse models to investigate the effects of disrupting complex I, complex III, or complex IV on β-cell function. Although all KO models had similar mitochondrial respiratory defects, complex III caused early hyperglycemia, glucose intolerance, and loss of glucose-stimulated insulin secretion in vivo. However, ex vivo insulin secretion did not change. Complex I and IV KO models showed diabetic phenotypes much later. Mitochondrial Ca2+ responses to glucose stimulation 3 weeks after gene deletion ranged from not affected to severely disrupted, depending on the complex targeted, supporting the unique roles of each complex in β-cell signaling. Mitochondrial antioxidant enzyme immunostaining increased in islets from complex III KO, but not from complex I or IV KO mice, indicating that severe diabetic phenotype in the complex III-deficient mice is causing alterations in cellular redox status. The present study highlights that defects in individual OxPhos complexes lead to different pathogenic outcomes. ARTICLE HIGHLIGHTS Mitochondrial metabolism is critical for β-cell insulin secretion, and mitochondrial dysfunction is involved in type 2 diabetes pathogenesis. We determined whether individual oxidative phosphorylation complexes contribute uniquely to β-cell function. Compared with loss of complex I and IV, loss of complex III resulted in severe in vivo hyperglycemia and altered β-cell redox status. Loss of complex III altered cytosolic and mitochondrial Ca2+ signaling and increased expression of glycolytic enzymes. Individual complexes contribute differently to β-cell function. This underscores the role of mitochondrial oxidative phosphorylation complex defects in diabetes pathogenesis.
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Affiliation(s)
- Anna L. Lang
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Nadee Nissanka
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Ruy A. Louzada
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Tamayo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Department of Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
| | - Elizabeth Pereira
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Department of Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
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13
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Ježek P. Pitfalls of Mitochondrial Redox Signaling Research. Antioxidants (Basel) 2023; 12:1696. [PMID: 37759999 PMCID: PMC10525995 DOI: 10.3390/antiox12091696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Redox signaling from mitochondria (mt) to the cytosol and plasma membrane (PM) has been scarcely reported, such as in the case of hypoxic cell adaptation or (2-oxo-) 2-keto-isocaproate (KIC) β-like-oxidation stimulating insulin secretion in pancreatic β-cells. Mutual redox state influence between mitochondrial major compartments, the matrix and the intracristal space, and the cytosol is therefore derived theoretically in this article to predict possible conditions, when mt-to-cytosol and mt-to-PM signals may occur, as well as conditions in which the cytosolic redox signaling is not overwhelmed by the mitochondrial antioxidant capacity. Possible peroxiredoxin 3 participation in mt-to-cytosol redox signaling is discussed, as well as another specific case, whereby mitochondrial superoxide release is diminished, whereas the matrix MnSOD is activated. As a result, the enhanced conversion to H2O2 allows H2O2 diffusion into the cytosol, where it could be a predominant component of the H2O2 release. In both of these ways, mt-to-cytosol and mt-to-PM signals may be realized. Finally, the use of redox-sensitive probes is discussed, which disturb redox equilibria, and hence add a surplus redox-buffering to the compartment, where they are localized. Specifically, when attempts to quantify net H2O2 fluxes are to be made, this should be taken into account.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic
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14
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Holendova B, Plecita-Hlavata L. Cysteine residues in signal transduction and its relevance in pancreatic beta cells. Front Endocrinol (Lausanne) 2023; 14:1221520. [PMID: 37455926 PMCID: PMC10339824 DOI: 10.3389/fendo.2023.1221520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Cysteine is one of the least abundant but most conserved amino acid residues in proteins, playing a role in their structure, metal binding, catalysis, and redox chemistry. Thiols present in cysteines can be modified by post-translational modifications like sulfenylation, acylation, or glutathionylation, regulating protein activity and function and serving as signals. Their modification depends on their position in the structure, surrounding amino acids, solvent accessibility, pH, etc. The most studied modifications are the redox modifications by reactive oxygen, nitrogen, and sulfur species, leading to reversible changes that serve as cell signals or irreversible changes indicating oxidative stress and cell damage. Selected antioxidants undergoing reversible oxidative modifications like peroxiredoxin-thioredoxin system are involved in a redox-relay signaling that can propagate to target proteins. Cysteine thiols can also be modified by acyl moieties' addition (derived from lipid metabolism), resulting in protein functional modification or changes in protein anchoring in the membrane. In this review, we update the current knowledge on cysteine modifications and their consequences in pancreatic β-cells. Because β-cells exhibit well-balanced redox homeostasis, the redox modifications of cysteines here serve primarily for signaling purposes. Similarly, lipid metabolism provides regulatory intermediates that have been shown to be necessary in addition to redox modifications for proper β-cell function and, in particular, for efficient insulin secretion. On the contrary, the excess of reactive oxygen, nitrogen, and sulfur species and the imbalance of lipids under pathological conditions cause irreversible changes and contribute to oxidative stress leading to cell failure and the development of type 2 diabetes.
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Affiliation(s)
| | - Lydie Plecita-Hlavata
- Laboratory of Pancreatic Islet Research, Institute of Physiology, Czech Academy of Sciences, Prague, Czechia
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15
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Elksnis A, Welsh N, Wikström P, Lau J, Carlsson PO. The selective NOX4 inhibitor GLX7013159 decreases blood glucose concentrations and human beta-cell apoptotic rates in diabetic NMRI nu/nu mice transplanted with human islets. Free Radic Res 2023; 57:460-469. [PMID: 37972305 DOI: 10.1080/10715762.2023.2284637] [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: 02/09/2023] [Accepted: 10/29/2023] [Indexed: 11/19/2023]
Abstract
NADPH oxidase 4 (NOX4) inhibition has been reported to mitigate diabetes-induced beta-cell dysfunction and improve survival in vitro, as well as counteract high-fat diet-induced glucose intolerance in mice. We investigated the antidiabetic effects of the selective NOX4 inhibitor GLX7013159 in vivo in athymic diabetic mice transplanted with human islets over a period of 4 weeks. The GLX7013159-treated mice achieved lower blood glucose and water consumption throughout the treatment period. Furthermore, GLX7013159 treatment resulted in improved insulin and c-peptide levels, better insulin secretion capacity, as well as in greatly reduced apoptotic rates of the insulin-positive human cells, measured as colocalization of insulin and cleaved caspase-3. We conclude that the antidiabetic effects of NOX4 inhibition by GLX7013159 are observed also during a prolonged study period in vivo and are likely to be due to an improved survival and function of the human beta-cells.
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Affiliation(s)
- Andris Elksnis
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Nils Welsh
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Joey Lau
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Per-Ola Carlsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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16
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Noguera Hurtado H, Gresch A, Düfer M. NMDA receptors - regulatory function and pathophysiological significance for pancreatic beta cells. Biol Chem 2023; 404:311-324. [PMID: 36626848 DOI: 10.1515/hsz-2022-0236] [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: 07/26/2022] [Accepted: 11/29/2022] [Indexed: 01/11/2023]
Abstract
Due to its unique features amongst ionotropic glutamate receptors, the NMDA receptor is of special interest in the physiological context but even more as a drug target. In the pathophysiology of metabolic disorders, particularly type 2 diabetes mellitus, there is evidence that NMDA receptor activation contributes to disease progression by impairing beta cell function. Consequently, channel inhibitors are suggested for treatment, but up to now there are many unanswered questions about the signaling pathways NMDA receptors are interfering with in the islets of Langerhans. In this review we give an overview about channel structure and function with special regard to the pancreatic beta cells and the regulation of insulin secretion. We sum up which signaling pathways from brain research have already been transferred to the beta cell, and what still needs to be proven. The main focus is on the relationship between an over-stimulated NMDA receptor and the production of reactive oxygen species, the amount of which is crucial for beta cell function. Finally, pilot studies using NMDA receptor blockers to protect the islet from dysfunction are reviewed and future perspectives for the use of such compounds in the context of impaired glucose homeostasis are discussed.
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Affiliation(s)
- Héctor Noguera Hurtado
- Institute of Pharmaceutical and Medicinal Chemistry, Department of Pharmacology, University of Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Anne Gresch
- Institute of Pharmaceutical and Medicinal Chemistry, Department of Pharmacology, University of Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Martina Düfer
- Institute of Pharmaceutical and Medicinal Chemistry, Department of Pharmacology, University of Münster, Corrensstraße 48, D-48149 Münster, Germany
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17
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Li K, Xu K, He Y, Yang Y, Tan M, Mao Y, Zou Y, Feng Q, Luo Z, Cai K. Oxygen Self-Generating Nanoreactor Mediated Ferroptosis Activation and Immunotherapy in Triple-Negative Breast Cancer. ACS NANO 2023; 17:4667-4687. [PMID: 36861638 DOI: 10.1021/acsnano.2c10893] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The hypoxia microenvironment of solid tumors poses a technological bottleneck for ferroptosis and immunotherapy in clinical oncology. Nanoreactors based on special physiological signals in tumor cells are able to avoid various tumor tolerance mechanisms by alleviating the intracellular hypoxia environment. Herein we reported a nanoreactor Cu2-xSe that enabled the conversion of Cu elements between Cu+ and Cu2+ for the generation of O2 and the consumption of intracellular GSH content. Furthermore, to enhance the catalytic and ferroptosis-inducing activities of the nanoreactors, the ferroptosis agonist Erastin was loaded on the ZIF-8 coating on the surface of Cu2-xSe to up-regulate the expression of NOX4 protein, increase the intracellular H2O2 content, catalyze the Cu+ to produce O2 and activate ferroptosis. In addition, the nanoreactors were simultaneously surface functionalized with PEG polymer and folic acid molecules, which ensured the in vivo blood circulation and tumor-specific uptake. In vitro and in vivo experiments demonstrated that the functionalized self-supplying nanoreactors can amplify the ability to generate O2 and consume intracellular GSH via the interconversion of Cu elements Cu+ and Cu2+, and impair the GPX4/GSH pathway and HIF-1α protein expression. At the same time, by alleviating the intracellular hypoxia environment, the expression of miR301, a gene in the secreted exosomes was decreased, which ultimately affected the phenotype polarization of TAMs and increased the content of IFN γ secreted by CD8+ T cells, which further promoted the ferroptosis induced by Erastin-loaded nanoreactors. This combined therapeutic strategy of activating the tumor immune response and ferroptosis via self-supplying nanoreactors provides a potential strategy for clinical application.
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Affiliation(s)
- Ke Li
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Kun Xu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Ye He
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, United States
| | - Yulu Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Meijun Tan
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Yulan Mao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Yanan Zou
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Qian Feng
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
| | - Zhong Luo
- School of Life Science, Chongqing University, Chongqing 400044, P. R. China
| | - Kaiyong Cai
- Key Laboratory of Biorheological Science and Technology, Ministry of Education College of Bioengineering, Chongqing University, Chongqing 400044, P. R. China
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18
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Deficiency of transcription factor Nkx6.1 does not prevent insulin secretion in INS-1E cells. Sci Rep 2023; 13:683. [PMID: 36639413 PMCID: PMC9839711 DOI: 10.1038/s41598-023-27985-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 01/11/2023] [Indexed: 01/14/2023] Open
Abstract
Pancreatic-β-cell-specifying transcription factor Nkx6.1, indispensable for embryonic development of the pancreatic epithelium and commitment to β-cell lineage, directly controls the expression of a glucose transporter (Glut2), pyruvate carboxylase (Pcx), and genes for insulin processing (endoplasmic reticulum oxidoreductase-1β, Ero1lb; zinc transporter-8, Slc30a8). The Nkx6.1 decline in aging diabetic Goto-Kakizaki rats contributes to β-cell trans-differentiation into δ-cells. Elucidating further Nkx6.1 roles, we studied Nkx6.1 ablation in rat INS-1E cells, prepared by CRISPR/Cas9 gene editing from single colonies. INS-1ENkx6.1-/- cells exhibited unchanged glucose-stimulated insulin secretion (GSIS), moderately decreased phosphorylating/non-phosphorylating respiration ratios at high glucose; unchanged but delayed ATP-elevation responses to glucose; delayed uptake of fluorescent glucose analog, but slightly improved cytosolic Ca2+-oscillations, induced by glucose; despite approximately halved Glut2, Pcx, Ero1lb, and Slc30a8 expression, and reduced nuclear receptors Nr4a1 and Nr4a3. Thus, ATP synthesis was time-compensated, despite the delayed GLUT2-mediated glucose uptake and crippled pyruvate-malate redox shuttle (owing to the PCX-deficiency) in INS-1ENkx6.1-/- cells. Nkx6.1 thus controls the expression of genes that are not essential for acute insulin secretion, the function of which can be compensated for. Considerations that Nkx6.1 deficiency is an ultimate determinant of β-cell pathology beyond cell trans-(de-)differentiation or β-cell identity are not supported by our results.
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19
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Möller M, Orrico F, Villar S, López AC, Silva N, Donzé M, Thomson L, Denicola A. Oxidants and Antioxidants in the Redox Biochemistry of Human Red Blood Cells. ACS OMEGA 2023; 8:147-168. [PMID: 36643550 PMCID: PMC9835686 DOI: 10.1021/acsomega.2c06768] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/09/2022] [Indexed: 06/01/2023]
Abstract
Red blood cells (RBCs) are exposed to both external and internal sources of oxidants that challenge their integrity and compromise their physiological function and supply of oxygen to tissues. Autoxidation of oxyhemoglobin is the main source of endogenous RBC oxidant production, yielding superoxide radical and then hydrogen peroxide. In addition, potent oxidants from other blood cells and the surrounding endothelium can reach the RBCs. Abundant and efficient enzymatic systems and low molecular weight antioxidants prevent most of the damage to the RBCs and also position the RBCs as a sink of vascular oxidants that allow the body to maintain a healthy circulatory system. Among the antioxidant enzymes, the thiol-dependent peroxidase peroxiredoxin 2, highly abundant in RBCs, is essential to keep the redox balance. A great part of the RBC antioxidant activity is supported by an active glucose metabolism that provides reducing power in the form of NADPH via the pentose phosphate pathway. There are several RBC defects and situations that generate oxidative stress conditions where the defense mechanisms are overwhelmed, and these include glucose-6-phosphate dehydrogenase deficiencies (favism), hemoglobinopathies like sickle cell disease and thalassemia, as well as packed RBCs for transfusion that suffer from storage lesions. These oxidative stress-associated pathologies of the RBCs underline the relevance of redox balance in these anucleated cells that lack a mechanism of DNA-inducible antioxidant response and rely on a complex and robust network of antioxidant systems.
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Affiliation(s)
- Matias
N. Möller
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
| | - Florencia Orrico
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo 11400, Uruguay
| | - Sebastián
F. Villar
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
| | - Ana C. López
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo 11400, Uruguay
| | - Nicolás Silva
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo 11400, Uruguay
- Departamento
de Medicina Transfusional, Hospital de Clínicas, Facultad de
Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | - Marcel Donzé
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
| | - Leonor Thomson
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo 11400, Uruguay
| | - Ana Denicola
- Laboratorio
de Fisicoquímica Biológica, Instituto de Química
Biológica, Facultad de Ciencias,
Universidad de la República, Montevideo 11400, Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo 11800, Uruguay
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20
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Hofmann A, Frank F, Wolk S, Busch A, Klimova A, Sabarstinski P, Gerlach M, Egorov D, Kopaliani I, Weinert S, Hamann B, Poitz DM, Brunssen C, Morawietz H, Schröder K, Reeps C. NOX4 mRNA correlates with plaque stability in patients with carotid artery stenosis. Redox Biol 2022; 57:102473. [PMID: 36182808 PMCID: PMC9526188 DOI: 10.1016/j.redox.2022.102473] [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: 08/29/2022] [Accepted: 09/09/2022] [Indexed: 11/24/2022] Open
Abstract
Carotid artery stenosis (CAS) develops from atherosclerotic lesions and plaques. Plaque rupture or stenosis may result in occlusion of the carotid artery. Accordingly, the asymptomatic disease becomes symptomatic, characterized by ischemic stroke or transient ischemic attacks, indicating an urgent need for better understanding of the underlying molecular mechanisms and eventually prevent symptomatic CAS. NOX4, a member of the NADPH oxidase family, has anti-atherosclerotic and anti-inflammatory properties in animal models of early atherosclerosis. We hypothesized that NOX4 mRNA expression is linked to protective mechanisms in CAS patients with advanced atherosclerotic lesions as well. Indeed, NOX4 mRNA expression is lower in patients with symptomatic CAS. A low NOX4 mRNA expression is associated with an increased risk of the development of clinical symptoms. In fact, NOX4 appears to be linked to plaque stability, apoptosis and plaque hemorrhage. This is supported by cleaved caspase-3 and glycophorin C and correlates inversely with plaque NOX4 mRNA expression. Even healing of a ruptured plaque appears to be connected to NOX4, as NOX4 mRNA expression correlates to fibrous cap collagen and is reciprocally related to MMP9 activity. In conclusion, low intra-plaque NOX4 mRNA expression is associated with an increased risk for symptomatic outcome and with reduced plaque stabilizing mechanisms suggesting protective effects of NOX4 in human advanced atherosclerosis.
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Affiliation(s)
- Anja Hofmann
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany.
| | - Frieda Frank
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Steffen Wolk
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Albert Busch
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Anna Klimova
- Core Unit Data Management and Analytics, National Center for Tumor Diseases Dresden, Partner Site Dresden, University Cancer Center (NCT/UCC), Dresden, Germany
| | - Pamela Sabarstinski
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Michael Gerlach
- Core Facility Cellular Imaging (CFCI), Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Dmitry Egorov
- Institute for Physiology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Irakli Kopaliani
- Institute for Physiology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Sönke Weinert
- Internal Medicine, Department of Cardiology and Angiology, Health Campus Immunology, Infectiology and Inflammation, Magdeburg University, Magdeburg, Germany
| | - Bianca Hamann
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany
| | - David M Poitz
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Coy Brunssen
- Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Henning Morawietz
- Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Katrin Schröder
- Institute for Cardiovascular Physiology, Goethe University, Frankfurt am Main, Germany and German Center of Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Christian Reeps
- Division of Vascular and Endovascular Surgery, Department of Visceral, Thoracic and Vascular Surgery, University Hospital and Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Germany
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21
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Wrublewsky S, Glas J, Carlein C, Nalbach L, Hoffmann MDA, Pack M, Vilas-Boas EA, Ribot N, Kappl R, Menger MD, Laschke MW, Ampofo E, Roma LP. The loss of pancreatic islet NADPH oxidase (NOX)2 improves islet transplantation. Redox Biol 2022; 55:102419. [PMID: 35933903 PMCID: PMC9357848 DOI: 10.1016/j.redox.2022.102419] [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: 07/01/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 10/31/2022] Open
Abstract
Islet transplantation is a promising treatment strategy for type 1 diabetes mellitus (T1DM) patients. However, oxidative stress-induced graft failure due to an insufficient revascularization is a major problem of this therapeutic approach. NADPH oxidase (NOX)2 is an important producer of reactive oxygen species (ROS) and several studies have already reported that this enzyme plays a crucial role in the endocrine function and viability of β-cells. Therefore, we hypothesized that targeting islet NOX2 improves the outcome of islet transplantation. To test this, we analyzed the cellular composition and viability of isolated wild-type (WT) and Nox2-/- islets by immunohistochemistry as well as different viability assays. Ex vivo, the effect of Nox2 deficiency on superoxide production, endocrine function and anti-oxidant protein expression was studied under hypoxic conditions. In vivo, we transplanted WT and Nox2-/- islets into mouse dorsal skinfold chambers and under the kidney capsule of diabetic mice to assess their revascularization and endocrine function, respectively. We found that the loss of NOX2 does not affect the cellular composition and viability of isolated islets. However, decreased superoxide production, higher glucose-stimulated insulin secretion as well as expression of nuclear factor erythroid 2-related factor (Nrf)2, heme oxygenase (HO)-1 and superoxide dismutase 1 (SOD1) was detected in hypoxic Nox2-/- islets when compared to WT islets. Moreover, we detected an early revascularization, a higher take rate and restoration of normoglycemia in diabetic mice transplanted with Nox2-/- islets. These findings indicate that the suppression of NOX2 activity represents a promising therapeutic strategy to improve engraftment and function of isolated islets.
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Affiliation(s)
- Selina Wrublewsky
- Institute for Clinical and Experimental Surgery, Saarland University, 66421, Homburg, Germany
| | - Julia Glas
- Institute for Clinical and Experimental Surgery, Saarland University, 66421, Homburg, Germany
| | - Christopher Carlein
- Department of Biophysics, Center for Human and Molecular Biology (ZHMB), Saarland University, 66421, Homburg, Germany
| | - Lisa Nalbach
- Institute for Clinical and Experimental Surgery, Saarland University, 66421, Homburg, Germany
| | | | - Mandy Pack
- Medical Biochemistry and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Eloisa Aparecida Vilas-Boas
- Department of Biophysics, Center for Human and Molecular Biology (ZHMB), Saarland University, 66421, Homburg, Germany; Department of Biochemistry, Institute of Chemistry, University of São Paulo (USP), São Paulo, 05508-900, Brazil
| | - Nathan Ribot
- Department of Biophysics, Center for Human and Molecular Biology (ZHMB), Saarland University, 66421, Homburg, Germany
| | - Reinhard Kappl
- Department of Biophysics, Center for Human and Molecular Biology (ZHMB), Saarland University, 66421, Homburg, Germany
| | - Michael D Menger
- Institute for Clinical and Experimental Surgery, Saarland University, 66421, Homburg, Germany
| | - Matthias W Laschke
- Institute for Clinical and Experimental Surgery, Saarland University, 66421, Homburg, Germany
| | - Emmanuel Ampofo
- Institute for Clinical and Experimental Surgery, Saarland University, 66421, Homburg, Germany
| | - Leticia Prates Roma
- Department of Biophysics, Center for Human and Molecular Biology (ZHMB), Saarland University, 66421, Homburg, Germany.
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22
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Merrins MJ, Corkey BE, Kibbey RG, Prentki M. Metabolic cycles and signals for insulin secretion. Cell Metab 2022; 34:947-968. [PMID: 35728586 PMCID: PMC9262871 DOI: 10.1016/j.cmet.2022.06.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 06/01/2022] [Accepted: 06/04/2022] [Indexed: 02/03/2023]
Abstract
In this review, we focus on recent developments in our understanding of nutrient-induced insulin secretion that challenge a key aspect of the "canonical" model, in which an oxidative phosphorylation-driven rise in ATP production closes KATP channels. We discuss the importance of intrinsic β cell metabolic oscillations; the phasic alignment of relevant metabolic cycles, shuttles, and shunts; and how their temporal and compartmental relationships align with the triggering phase or the secretory phase of pulsatile insulin secretion. Metabolic signaling components are assigned regulatory, effectory, and/or homeostatic roles vis-à-vis their contribution to glucose sensing, signal transmission, and resetting the system. Taken together, these functions provide a framework for understanding how allostery, anaplerosis, and oxidative metabolism are integrated into the oscillatory behavior of the secretory pathway. By incorporating these temporal as well as newly discovered spatial aspects of β cell metabolism, we propose a much-refined MitoCat-MitoOx model of the signaling process for the field to evaluate.
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Affiliation(s)
- Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI, USA.
| | - Barbara E Corkey
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
| | - Richard G Kibbey
- Departments of Internal Medicine (Endocrinology) and Cellular & Molecular Physiology, Yale University, New Haven, CT, USA.
| | - Marc Prentki
- Molecular Nutrition Unit and Montreal Diabetes Research Center, CRCHUM, and Departments of Nutrition, Biochemistry and Molecular Medicine, Université de Montréal, Montréal, ON, Canada.
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23
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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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24
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Reciprocal Regulation of Shh Trafficking and H2O2 Levels via a Noncanonical BOC-Rac1 Pathway. Antioxidants (Basel) 2022; 11:antiox11040718. [PMID: 35453403 PMCID: PMC9025708 DOI: 10.3390/antiox11040718] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/25/2022] [Accepted: 04/03/2022] [Indexed: 11/21/2022] Open
Abstract
Among molecules that bridge environment, cell metabolism, and cell signaling, hydrogen peroxide (H2O2) recently appeared as an emerging but central player. Its level depends on cell metabolism and environment and was recently shown to play key roles during embryogenesis, contrasting with its long-established role in disease progression. We decided to explore whether the secreted morphogen Sonic hedgehog (Shh), known to be essential in a variety of biological processes ranging from embryonic development to adult tissue homeostasis and cancers, was part of these interactions. Here, we report that H2O2 levels control key steps of Shh delivery in cell culture: increased levels reduce primary secretion, stimulate endocytosis and accelerate delivery to recipient cells; in addition, physiological in vivo modulation of H2O2 levels changes Shh distribution and tissue patterning. Moreover, a feedback loop exists in which Shh trafficking controls H2O2 synthesis via a non-canonical BOC-Rac1 pathway, leading to cytoneme growth. Our findings reveal that Shh directly impacts its own distribution, thus providing a molecular explanation for the robustness of morphogenesis to both environmental insults and individual variability.
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25
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Andreadi A, Bellia A, Di Daniele N, Meloni M, Lauro R, Della-Morte D, Lauro D. The molecular link between oxidative stress, insulin resistance, and type 2 diabetes: A target for new therapies against cardiovascular diseases. Curr Opin Pharmacol 2021; 62:85-96. [PMID: 34959126 DOI: 10.1016/j.coph.2021.11.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 02/07/2023]
Abstract
Type 2 Diabetes Mellitus (T2D) is a chronic disease with a pandemic incidence whose pathogenesis has not yet been clarified. Raising evidence highlighted the role of oxidative stress in inducing insulin resistance, pancreatic beta-cell dysfunction, and leading to cardiovascular disease (CVD). Therefore, understanding the link between oxidative stress, T2D and CVD may help to further understand the pathological processes beyond this association, to personalize the algorithm of the cure, and to find new therapeutic targets. Here, we discussed the role of oxidative stress and the decrease of antioxidant defenses in the pathogenesis of T2D. Furthermore, some aspects of hypoglycemic therapies and their potential role as antioxidant agents were examined, which might be pivotal in preventing CVD in T2D patients.
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Affiliation(s)
- Aikaterini Andreadi
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; University Hospital Fondazione Policlinico Tor Vergata, Rome, Italy
| | - Alfonso Bellia
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; University Hospital Fondazione Policlinico Tor Vergata, Rome, Italy
| | - Nicola Di Daniele
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; University Hospital Fondazione Policlinico Tor Vergata, Rome, Italy
| | - Marco Meloni
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; University Hospital Fondazione Policlinico Tor Vergata, Rome, Italy
| | - Renato Lauro
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - David Della-Morte
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; University Hospital Fondazione Policlinico Tor Vergata, Rome, Italy; San Raffaele Rome Open University, Rome, Italy; Department of Neurology, Evelyn F. McKnight Brain Institute, Miller School, Miami, USA
| | - Davide Lauro
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; University Hospital Fondazione Policlinico Tor Vergata, Rome, Italy.
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26
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Vilas-Boas EA, Almeida DC, Roma LP, Ortis F, Carpinelli AR. Lipotoxicity and β-Cell Failure in Type 2 Diabetes: Oxidative Stress Linked to NADPH Oxidase and ER Stress. Cells 2021; 10:cells10123328. [PMID: 34943836 PMCID: PMC8699655 DOI: 10.3390/cells10123328] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/17/2022] Open
Abstract
A high caloric intake, rich in saturated fats, greatly contributes to the development of obesity, which is the leading risk factor for type 2 diabetes (T2D). A persistent caloric surplus increases plasma levels of fatty acids (FAs), especially saturated ones, which were shown to negatively impact pancreatic β-cell function and survival in a process called lipotoxicity. Lipotoxicity in β-cells activates different stress pathways, culminating in β-cells dysfunction and death. Among all stresses, endoplasmic reticulum (ER) stress and oxidative stress have been shown to be strongly correlated. One main source of oxidative stress in pancreatic β-cells appears to be the reactive oxygen species producer NADPH oxidase (NOX) enzyme, which has a role in the glucose-stimulated insulin secretion and in the β-cell demise during both T1 and T2D. In this review, we focus on the acute and chronic effects of FAs and the lipotoxicity-induced β-cell failure during T2D development, with special emphasis on the oxidative stress induced by NOX, the ER stress, and the crosstalk between NOX and ER stress.
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Affiliation(s)
- Eloisa Aparecida Vilas-Boas
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, Brazil
- Department of Biochemistry, Institute of Chemistry, University of São Paulo (USP), São Paulo 05508-900, Brazil
- Correspondence: (E.A.V.-B.); (A.R.C.); Tel.: +55-(11)-3091-7246 (A.R.C.)
| | - Davidson Correa Almeida
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, Brazil; (D.C.A.); (F.O.)
| | - Leticia Prates Roma
- Center for Human and Molecular Biology (ZHMB), Department of Biophysics, Saarland University, 66424 Homburg, Germany;
| | - Fernanda Ortis
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, Brazil; (D.C.A.); (F.O.)
| | - Angelo Rafael Carpinelli
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo 05508-000, Brazil
- Correspondence: (E.A.V.-B.); (A.R.C.); Tel.: +55-(11)-3091-7246 (A.R.C.)
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27
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Lin H, Smith N, Spigelman AF, Suzuki K, Ferdaoussi M, Alghamdi TA, Lewandowski SL, Jin Y, Bautista A, Wang YW, Manning Fox JE, Merrins MJ, Buteau J, MacDonald PE. β-Cell Knockout of SENP1 Reduces Responses to Incretins and Worsens Oral Glucose Tolerance in High-Fat Diet-Fed Mice. Diabetes 2021; 70:2626-2638. [PMID: 34462260 PMCID: PMC8564408 DOI: 10.2337/db20-1235] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 08/19/2021] [Indexed: 01/17/2023]
Abstract
SUMOylation reduces oxidative stress and preserves islet mass at the expense of robust insulin secretion. To investigate a role for the deSUMOylating enzyme sentrin-specific protease 1 (SENP1) following metabolic stress, we put pancreas/gut-specific SENP1 knockout (pSENP1-KO) mice on a high-fat diet (HFD). Male pSENP1-KO mice were more glucose intolerant following HFD than littermate controls but only in response to oral glucose. A similar phenotype was observed in females. Plasma glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) responses were identical in pSENP1-KO and wild-type littermates, including the HFD-induced upregulation of GIP responses. Islet mass was not different, but insulin secretion and β-cell exocytotic responses to the GLP-1 receptor agonist exendin-4 (Ex4) and GIP were impaired in islets lacking SENP1. Glucagon secretion from pSENP1-KO islets was also reduced, so we generated β-cell-specific SENP1 KO mice. These phenocopied the pSENP1-KO mice with selective impairment in oral glucose tolerance following HFD, preserved islet mass expansion, and impaired β-cell exocytosis and insulin secretion to Ex4 and GIP without changes in cAMP or Ca2+ levels. Thus, β-cell SENP1 limits oral glucose intolerance following HFD by ensuring robust insulin secretion at a point downstream of incretin signaling.
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Affiliation(s)
- Haopeng Lin
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Nancy Smith
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Aliya F Spigelman
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Kunimasa Suzuki
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Mourad Ferdaoussi
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Tamadher A Alghamdi
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Sophie L Lewandowski
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison
| | - Yaxing Jin
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Austin Bautista
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Ying Wayne Wang
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Jocelyn E Manning Fox
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison
| | - Jean Buteau
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
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28
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Corkey BE, Deeney JT, Merrins MJ. What Regulates Basal Insulin Secretion and Causes Hyperinsulinemia? Diabetes 2021; 70:2174-2182. [PMID: 34593535 PMCID: PMC8576498 DOI: 10.2337/dbi21-0009] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/28/2021] [Indexed: 12/12/2022]
Abstract
We hypothesize that basal hyperinsulinemia is synergistically mediated by an interplay between increased oxidative stress and excess lipid in the form of reactive oxygen species (ROS) and long-chain acyl-CoA esters (LC-CoA). In addition, ROS production may increase in response to inflammatory cytokines and certain exogenous environmental toxins that mislead β-cells into perceiving nutrient excess when none exists. Thus, basal hyperinsulinemia is envisioned as an adaptation to sustained real or perceived nutrient excess that only manifests as a disease when the excess demand can no longer be met by an overworked β-cell. In this article we will present a testable hypothetical mechanism to explain the role of lipids and ROS in basal hyperinsulinemia and how they differ from glucose-stimulated insulin secretion (GSIS). The model centers on redox regulation, via ROS, and S-acylation-mediated trafficking via LC-CoA. These pathways are well established in neural systems but not β-cells. During GSIS, these signals rise and fall in an oscillatory pattern, together with the other well-established signals derived from glucose metabolism; however, their precise roles have not been defined. We propose that failure to either increase or decrease ROS or LC-CoA appropriately will disturb β-cell function.
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Affiliation(s)
- Barbara E Corkey
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Jude T Deeney
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Matthew J Merrins
- Department of Biomolecular Chemistry and Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
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29
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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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30
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Lupin γ-conglutin protects against cell death induced by oxidative stress and lipotoxicity, but transiently inhibits in vitro insulin secretion by increasing K ATP channel currents. Int J Biol Macromol 2021; 187:76-90. [PMID: 34280449 DOI: 10.1016/j.ijbiomac.2021.07.088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 07/03/2021] [Accepted: 07/13/2021] [Indexed: 02/08/2023]
Abstract
Lupin γ-conglutin beneficially modulates glycemia, but whether it protects against oxidative and lipotoxic damage remains unknown. Here, we studied the effects of γ-conglutin on cell death provoked by hydrogen peroxide and palmitate in HepG2 hepatocytes and insulin-producing MIN6 cells, and if a modulation of mitochondrial potential and reactive oxygen species (ROS) levels was involved. We also investigated how γ-conglutin influences insulin secretion and electrical activity of β-cells. The increased apoptosis of HepG2 cells exposed to hydrogen peroxide was prevented by γ-conglutin, and the viability and ROS content in γ-conglutin-treated cells was similar to that of non-exposed cells. Additionally, γ-conglutin partially protected MIN6 cells against hydrogen peroxide-induced death. This was associated with a marked reduction in ROS. No significant changes were found in the mitochondrial potential of γ-conglutin-treated cells. Besides, we observed a partial protection against lipotoxicity only in hepatocytes. Unexpectedly, we found a transient inhibition of insulin secretion, plasma membrane hyperpolarization, and higher KATP channel currents in β-cells treated with γ-conglutin. Our data show that γ-conglutin protects against cell death induced by oxidative stress or lipotoxicity by decreasing ROS and might also indicate that γ-conglutin promotes a β-cell rest, which could be useful for preventing β-cell exhaustion in chronic hyperglycemia.
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Chai WF, Tang KS. Protective potential of cerium oxide nanoparticles in diabetes mellitus. J Trace Elem Med Biol 2021; 66:126742. [PMID: 33773280 DOI: 10.1016/j.jtemb.2021.126742] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/15/2021] [Accepted: 03/09/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND Diabetes mellitus (DM) is a non-communicable metabolic disease which is closely related to excessive oxidative stress after constant exposure to high plasma glucose. Although the current antidiabetic medications are effective in lowering blood glucose, these medications do not prevent or reverse the disease progression. Thus, there is a crucial need to explore new therapeutic interventions that could address this shortcoming. As cerium oxide nanoparticles (CONPs) possess antioxidant property, this agent may be used as a treatment option for the management of DM. PURPOSE This review aims to provide a critical evaluation of the pharmacological and antidiabetic effects of CONPs in cell and animal models. The roles of CONPs in attenuating DM complications are also presented in this report. METHODS We conducted a literature search in the PubMed database using the keywords "cerium oxide", "cerous oxide", "ceria", "nanoceria", and "diabetes" from inception to December 2020. The inclusion criteria were primary source articles that investigated the role of CONPs in DM and diabetic complications. RESULTS We identified 47 articles from the initial search. After the thorough screening, only 31 articles were included in this study. We found that CONPs can attenuate parameters that are related to DM and diabetic complications in various animals and cell culture models. CONCLUSION CONPs could potentially be used in the treatment of those with DM and complications caused by the disease.
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Affiliation(s)
- Wui Fang Chai
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Kim San Tang
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia.
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Rustenbeck I, Schulze T, Morsi M, Alshafei M, Panten U. What Is the Metabolic Amplification of Insulin Secretion and Is It (Still) Relevant? Metabolites 2021; 11:metabo11060355. [PMID: 34199454 PMCID: PMC8229681 DOI: 10.3390/metabo11060355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 12/24/2022] Open
Abstract
The pancreatic beta-cell transduces the availability of nutrients into the secretion of insulin. While this process is extensively modified by hormones and neurotransmitters, it is the availability of nutrients, above all glucose, which sets the process of insulin synthesis and secretion in motion. The central role of the mitochondria in this process was identified decades ago, but how changes in mitochondrial activity are coupled to the exocytosis of insulin granules is still incompletely understood. The identification of ATP-sensitive K+-channels provided the link between the level of adenine nucleotides and the electrical activity of the beta cell, but the depolarization-induced Ca2+-influx into the beta cells, although necessary for stimulated secretion, is not sufficient to generate the secretion pattern as produced by glucose and other nutrient secretagogues. The metabolic amplification of insulin secretion is thus the sequence of events that enables the secretory response to a nutrient secretagogue to exceed the secretory response to a purely depolarizing stimulus and is thus of prime importance. Since the cataplerotic export of mitochondrial metabolites is involved in this signaling, an orienting overview on the topic of nutrient secretagogues beyond glucose is included. Their judicious use may help to define better the nature of the signals and their mechanism of action.
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Affiliation(s)
- Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
- Correspondence: ; Tel.: +49-(0)53-139-156-70
| | - Torben Schulze
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| | - Mai Morsi
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
- Department of Pharmacology, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
| | - Mohammed Alshafei
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| | - Uwe Panten
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
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Chen Y, He M, Lei MML, Ko WKW, Lin C, Bian Z, Wong AOL. Mouse Spexin: (III) Differential Regulation by Glucose and Insulin in Glandular Stomach and Functional Implication in Feeding Control. Front Endocrinol (Lausanne) 2021; 12:681648. [PMID: 34025589 PMCID: PMC8138665 DOI: 10.3389/fendo.2021.681648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/19/2021] [Indexed: 11/24/2022] Open
Abstract
Spexin (SPX), a neuropeptide with diverse functions, is a novel satiety factor in fish models and its role in feeding control has been recently confirmed in mammals. In mouse, food intake was shown to trigger SPX expression in glandular stomach with parallel rise in serum SPX and these SPX signals could inhibit feeding via central actions within the hypothalamus. However, the mechanisms for SPX regulation by food intake are still unclear. To examine the role of insulin signal caused by glucose uptake in SPX regulation, the mice were IP injected with glucose and insulin, respectively. In this case, serum SPX was elevated by glucose but not altered by insulin. Meanwhile, SPX transcript expression in the glandular stomach was up-regulated by glucose but the opposite was true for insulin treatment. Using in situ hybridization, the differential effects on SPX gene expression were located in the gastric mucosa of glandular stomach. Co-injection experiments also revealed that glucose stimulation on serum SPX and SPX mRNA expressed in glandular stomach could be blocked by insulin. In gastric mucosal cells prepared from glandular stomach, the opposite effects on SPX transcript expression by glucose and insulin could still be noted with similar blockade of the stimulatory effects of glucose by insulin. In this cell model, SPX gene expression induced by glucose was mediated by glucose uptake via GLUT, ATP synthesis by glycolysis/respiratory chain, and subsequent modulation of KATP channel activity, but the voltage-sensitive Ca2+ channels were not involved. The corresponding inhibition by insulin, however, was mediated by PI3K/Akt, MEK1/2/ERK1/2, and P38MAPK cascades coupled to insulin receptor but not IGF-1 receptor. Apparently, glucose uptake in mice can induce SPX expression in the glandular stomach through ATP synthesis via glucose metabolism and subsequent modification of KATP channel activity, which may contribute to SPX release into circulation to act as the satiety signal after food intake. The insulin rise caused by glucose uptake, presumably originated from the pancreas, may serve as a negative feedback to inhibit the SPX response by activating MAPK and PI3K/Akt pathways in the stomach.
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Affiliation(s)
- Yuan Chen
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Mulan He
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Martina M. L. Lei
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Wendy K. W. Ko
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Chengyuan Lin
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, Hong Kong
| | - Zhaoxiang Bian
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, Hong Kong
| | - Anderson O. L. Wong
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong
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Manuel R, Lima MDS, Dilly S, Daunay S, Abbe P, Pramil E, Solier S, Guillaumond F, Tubiana SS, Escargueil A, Pêgas Henriques JA, Ferrand N, Erdelmeier I, Boucher JL, Bertho G, Agranat I, Rocchi S, Sabbah M, Slama Schwok A. Distinction between 2'- and 3'-Phosphate Isomers of a Fluorescent NADPH Analogue Led to Strong Inhibition of Cancer Cells Migration. Antioxidants (Basel) 2021; 10:antiox10050723. [PMID: 34064498 PMCID: PMC8148004 DOI: 10.3390/antiox10050723] [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: 12/29/2020] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 11/16/2022] Open
Abstract
Specific inhibition of NADPH oxidases (NOX) and NO-synthases (NOS), two enzymes associated with redox stress in tumor cells, has aroused great pharmacological interest. Here, we show how these enzymes distinguish between isomeric 2′- and 3′-phosphate derivatives, a difference used to improve the specificity of inhibition by isolated 2′- and 3′-phosphate isomers of our NADPH analogue NS1. Both isomers become fluorescent upon binding to their target proteins as observed by in vitro assay and in vivo imaging. The 2′-phosphate isomer of NS1 exerted more pronounced effects on NOS and NOX-dependent physiological responses than the 3′-phosphate isomer did. Docking and molecular dynamics simulations explain this specificity at the level of the NADPH site of NOX and NOS, where conserved arginine residues distinguished between the 2′-phosphate over the 3′-phosphate group, in favor of the 2′-phosphate.
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Affiliation(s)
- Raoul Manuel
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - Michelle de Souza Lima
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - Sébastien Dilly
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - Sylvain Daunay
- Innoverda, Biopark Villejuif, F-94800 Villejuif, France; (S.D.); (I.E.)
| | - Patricia Abbe
- Centre Méditerranéen de Médecine Moléculaire (C3M), INSERM U1065, Team 12, F-06204 Nice, France; (P.A.); (S.R.)
| | - Elodie Pramil
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - Stéphanie Solier
- Gustave Roussy Cancer Center, INSERM U1170, F-94805 Villejuif, France;
| | - Fabienne Guillaumond
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, Aix-Marseille Univ., CNRS, UMR 7258, Institut Paoli-Calmettes, F-13288 Marseille, France; (F.G.); (S.-S.T.)
| | - Sarah-Simha Tubiana
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, Aix-Marseille Univ., CNRS, UMR 7258, Institut Paoli-Calmettes, F-13288 Marseille, France; (F.G.); (S.-S.T.)
| | - Alexandre Escargueil
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - João Antonio Pêgas Henriques
- Departamento de Biofísica/Centro de Biotecnologia, Universidade Federal Do Rio Grande Do Sul (UFRGS), Porto Alegre 90040-060, Brazil;
- Graduate Program in Biotechnology, Universidade do Vale do Taquari—Univates, Lajeado 95900-000, Brazil
| | - Nathalie Ferrand
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - Irène Erdelmeier
- Innoverda, Biopark Villejuif, F-94800 Villejuif, France; (S.D.); (I.E.)
| | - Jean-Luc Boucher
- CNRS UMR 8601, University Paris Descartes, F-75006 Paris, France; (J.-L.B.); (G.B.)
| | - Gildas Bertho
- CNRS UMR 8601, University Paris Descartes, F-75006 Paris, France; (J.-L.B.); (G.B.)
| | - Israel Agranat
- Organic Chemistry, Institute of Chemistry, Philadelphia Bldg #212, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| | - Stéphane Rocchi
- Centre Méditerranéen de Médecine Moléculaire (C3M), INSERM U1065, Team 12, F-06204 Nice, France; (P.A.); (S.R.)
| | - Michèle Sabbah
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
| | - Anny Slama Schwok
- Cancer Biology and Therapeutics Team, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Sorbonne Université, F-75012 Paris, France; (R.M.); (M.d.S.L.); (S.D.); (E.P.); (A.E.); (N.F.); (M.S.)
- Correspondence: or
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Krüger C, Waldeck-Weiermair M, Kaynert J, Pokrant T, Komaragiri Y, Otto O, Michel T, Elsner M. AQP8 is a crucial H 2O 2 transporter in insulin-producing RINm5F cells. Redox Biol 2021; 43:101962. [PMID: 33892285 PMCID: PMC8082690 DOI: 10.1016/j.redox.2021.101962] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 03/28/2021] [Accepted: 03/28/2021] [Indexed: 02/08/2023] Open
Abstract
Peroxiporins are distinct aquaporins (AQP) which, beside water, also facilitate the bidirectional transport of hydrogen peroxide (H2O2) across cellular membranes. H2O2 serves as the major reactive oxygen species that mediates essential cell signaling events. In pancreatic β-cells, H2O2 has been associated with the regulation of cell growth but in excess it leads to failure of insulin secretion, making it important for diabetes mellitus (DM) pathogenesis. In the present study, the role of aquaporin-8 (AQP8) as a peroxiporin was investigated in RINm5F cells. The role of AQP8 was studied in an insulin-producing cell model, on the basis of stable AQP8 overexpression (AQP8↑) and CRISPR/Cas9-mediated AQP8 knockdown (KD). A complete AQP8 knock-out was found to result in cell death, however we demonstrate that mild lentiviral re-expression through a Tet-On-regulated genetically modified AQP8 leads to cell survival, enabling functional characterization. Proliferation and insulin content were found to be increased in AQP8↑ cells underlining the importance of AQP8 in the regulation of H2O2 homeostasis in pancreatic β-cells. Colocalization analyses of V5-tagged AQP8 proteins based on confocal microscopic imaging revealed its membrane targeting to both the mitochondria and the plasma membrane, but not to the ER, the Golgi apparatus, insulin vesicles, or peroxisomes. By using the fluorescence H2O2 specific biosensor HyPer together with endogenous generation of H2O2 using d-amino acid oxidase, live cell imaging revealed enhanced H2O2 flux to the same subcellular regions in AQP8 overexpressing cells pointing to its importance in the development of type-1 DM. Moreover, the novel ultrasensitive H2O2 sensor HyPer7.2 clearly unveiled AQP8 as a H2O2 transporter in RINm5F cells. In summary, these studies establish that AQP8 is an important H2O2 pore in insulin-producing RINm5F cells involved in the transport of H2O2 through the mitochondria and cell membrane and may help to explain the H2O2 transport and toxicity in pancreatic β-cells. AQP8 KO is lethal for insulin-producing RINm5F cells. The peroxiporin AQP8 is localized in the plasma and mitochondrial membrane channeling H2O2 in RINm5F cells. Tet-On regulated low AQP8 re-expression and APQ8 overexpression are feasible models to study H2O2 transport in β-cells. Overexpression of AQP8 increases cell proliferation and cellular insulin content.
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Affiliation(s)
- Christina Krüger
- Institute of Clinical Biochemistry, Hannover Medical School, 30623, Hannover, Germany
| | - Markus Waldeck-Weiermair
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jonas Kaynert
- Institute of Clinical Biochemistry, Hannover Medical School, 30623, Hannover, Germany
| | - Thomas Pokrant
- Institute of Clinical Biochemistry, Hannover Medical School, 30623, Hannover, Germany
| | - Yesaswini Komaragiri
- Zentrum für Innovationskompetenz: Humorale Immunreaktion bei Kardiovaskulären Erkrankungen, Universität Greifswald, 17489, Greifswald, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung e. V., Standort Greifswald, Universitätsmedizin Greifswald, Fleischmannstr. 42, 17489, Greifswald, Germany
| | - Oliver Otto
- Zentrum für Innovationskompetenz: Humorale Immunreaktion bei Kardiovaskulären Erkrankungen, Universität Greifswald, 17489, Greifswald, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung e. V., Standort Greifswald, Universitätsmedizin Greifswald, Fleischmannstr. 42, 17489, Greifswald, Germany
| | - Thomas Michel
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Matthias Elsner
- Institute of Clinical Biochemistry, Hannover Medical School, 30623, Hannover, Germany.
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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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Marvibaigi M, Hosseini SM, Amini N. Launaea acanthodes (Boiss) O. Kuntze mediates hepatic glucose metabolism and ameliorates impaired pancreatic function in streptozotocin-induced diabetic rats. JOURNAL OF ETHNOPHARMACOLOGY 2021; 268:113577. [PMID: 33171271 DOI: 10.1016/j.jep.2020.113577] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/26/2020] [Accepted: 11/06/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Launaea acanthodes (Boiss.) O. Kuntze is native to semiarid regions of central Iran, traditionally used in the treatment of numerous disorders including diabetes. AIM OF THE STUDY The current study aimed to explore hypoglycemic activity of Launaea acanthodes extract in streptozotocin-induced diabetic rats. Furthermore, gene expression study was carried out to examine expression levels of key glucose metabolism-related genes. METHODS For in vitro study, Folin-Ciocalteus, DPPH and aluminum chloride colorimetric assays were used to determine the total phenolic content, antioxidant capacity and total flavonoid content of extracts, respectively. For in vivo study, streptozotocin-induced diabetic Wistar rats were orally administered with metformin (50 mg/kg) and various doses of extracts (100, 200 and 400 mg/kg body weight) for 28 days. Fasting blood glucose, body weight, food and water intake were assessed during the course of treatment. At the end of the intervention, oral glucose tolerance test (OGTT), lipid profile and glycated hemoglobin (HbA1c) were evaluated. Furthermore, functional liver enzymes, oxidative stress markers and histopathology of pancreas were examined. Lastly, quantitative real time polymerase chain reaction (qRT-PCR) was applied to explore the mRNA levels of genes relevant to glucose metabolism in the pancreas and liver tissues of diabetic rats. RESULTS Based on the in vitro results, the hydroalcoholic extract revealed potential radical scavenging activity and contained highest amount of phenolic and flavonoid. The in vivo results demonstrated that the extract lowered fasting blood glucose level, increased the body weight, restored the alterations in the levels of water and food intake, attenuated HbA1c, improved lipid profile and ameliorated the OGTT in diabetic rats. The extract administration alleviated the histopathological changes in the pancreas, suppressed malondialdehyde (MDA) level and further restored attenuated levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) in diabetic rats. Analysis of real time PCR data showed that extract administration reversed the expression levels of hepatic glucokinase (GK), phosphenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). Meanwhile, the extract upregulated the expression level of glucose transporter-2 (GLUT-2) and pancreatic-duodenal homeobox (PDX-1) in diabetic rats. CONCLUSION Collectively, the results demonstrate that Launaea acanthodes hydroalcoholic extract exerts hypoglycemic effect possibly via regulating key enzymes of glucose metabolism and ameliorating pancreatic dysfunction through its antioxidant properties.
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Affiliation(s)
- Mohsen Marvibaigi
- Medicine, Quran and Hadith Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Seyed Morteza Hosseini
- Medicine, Quran and Hadith Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - Neda Amini
- Department of Biology, Kavian Institute of Higher Education, Mashhad, Iran
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Krümmel B, Plötz T, Jörns A, Lenzen S, Mehmeti I. The central role of glutathione peroxidase 4 in the regulation of ferroptosis and its implications for pro-inflammatory cytokine-mediated beta-cell death. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166114. [PMID: 33662571 DOI: 10.1016/j.bbadis.2021.166114] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 02/01/2021] [Accepted: 02/24/2021] [Indexed: 02/08/2023]
Abstract
Pro-inflammatory cytokines are crucial mediators of beta-cell destruction in type 1 diabetes mellitus (T1DM). The involvement of ferroptosis as a form of oxidative non-apoptotic cell death in T1DM pathogenesis has not been elucidated so far. Moreover, the role of glutathione peroxidase 4 (GPx4) as an antioxidative enzyme and a major regulator of ferroptosis remains elusive. Assessment of GPx4 expression in different pancreatic islet cell types revealed a predominant expression in beta-cells. Silencing of GPx4 by RNA interference and exposure to tert-butyl hydroperoxide (tert-BHP) caused ferroptosis in rat pancreatic beta-cells as evidenced by non-apoptotic cell death in association with increased lipid peroxidation, disturbed ATP synthesis, reduced GSH content, and GPx4 degradation. GPx4 overexpression as well as the ferroptosis inhibitor ferrostatin-1 effectively attenuated beta-cell death induced by tert-BHP. Notably, beta-cell toxic cytokines did not induce ferroptosis although beta-cells underwent cell death. Inhibition of iNOS by Nω-nitro-L-arginine however led to a massive lipid peroxidation upon exposure to pro-inflammatory cytokines. Hence, nitric oxide produced during pro-inflammatory cytokine action prevents the induction of ferroptosis, thereby favouring apoptosis as a primary cell death mechanism. The extraordinarily high abundance of the phospholipid hydroperoxidase GPx4 in beta-cells in contrast to the very low expression in other islet cell types points to a susceptibility of beta-cells to the accumulation of toxic lipid peroxides. Overall, these data strongly suggest that GPx4 is indispensable for beta-cell function under physiological conditions. On the other hand, our results exclude an involvement of ferroptosis as an alternative beta-cell death mode under pro-inflammatory cytokine attack.
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Affiliation(s)
- Bastian Krümmel
- Institute of Experimental Diabetes Research, Hannover Medical School, 30625, Hannover, Germany; Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Thomas Plötz
- Institute of Experimental Diabetes Research, Hannover Medical School, 30625, Hannover, Germany; Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Anne Jörns
- Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Sigurd Lenzen
- Institute of Experimental Diabetes Research, Hannover Medical School, 30625, Hannover, Germany; Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany.
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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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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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Baumel-Alterzon S, Katz LS, Brill G, Garcia-Ocaña A, Scott DK. Nrf2: The Master and Captain of Beta Cell Fate. Trends Endocrinol Metab 2021; 32:7-19. [PMID: 33243626 PMCID: PMC7746592 DOI: 10.1016/j.tem.2020.11.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 02/07/2023]
Abstract
Prolonged hyperglycemia is toxic to pancreatic β cells, generating excessive reactive oxygen species, defective glucose-stimulated insulin secretion, decreased insulin production, and eventually β cell death and diabetes. Nrf2 is a master regulator of cellular responses to counteract dangerous levels of oxidative stress. Maintenance of β cell mass depends on Nrf2 to promote the survival, function, and proliferation of β cells. Indeed, Nrf2 activation decreases inflammation, increases insulin sensitivity, reduces body weight, and preserves β cell mass. Therefore, numerous pharmacological activators of Nrf2 are being tested in clinical trials for the treatment of diabetes and diabetic complications. Modulating Nrf2 activity in β cells is a promising therapeutic approach for the treatment of diabetes.
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Affiliation(s)
- Sharon Baumel-Alterzon
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Liora S Katz
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gabriel Brill
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Adolfo Garcia-Ocaña
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Donald K Scott
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Abstract
Reactive oxygen species (ROS) are ubiquitous metabolic products and important cellular signaling molecules that contribute to several biological functions. Pathophysiology arises when ROS are generated either in excess or in cell types or subcellular locations that normally do not produce ROS or when non-physiological types of ROS (e.g., superoxide instead of hydrogen peroxide) are formed. In the latter scenario, antioxidants were considered as the apparent remedy but, clinically, have consistently failed and even sometimes induced harm. The obvious reason for that is the non-selective ROS scavenging effects of antioxidants which interfere with both qualities of ROS, physiological and pathological. Therefore, it is essential to overcome this "antidote or neutralizer" strategy. We here review the most promising alternative approach by identifying the disease-relevant enzymatic sources of ROS, target these selectively, but leave physiological ROS signaling through other sources intact. Among all ROS sources, NADPH oxidases (NOX1-5 and DUOX1-2) stand out as their sole function is to produce ROS, whereas most other enzymatic sources only produce ROS as a by-product or upon biochemical uncoupling or damage. This qualifies NOXs as the main potential drug-target candidates in diseases associated with dysfunction in ROS signaling. As a reflection of this, the development of several NOX inhibitors has taken place. Recently, the WHO approved a new stem, "naxib," which refers to NADPH oxidase inhibitors, and thereby recognized NOX inhibitors as a new therapeutic class. This has been announced while clinical trials with the first-in-class compound, setanaxib (initially known as GKT137831) had been initiated. We also review the differences between the seven NOX family members in terms of structure and function in health and disease and then focus on the most advanced NOX inhibitors with an exclusive focus on clinically relevant validations and applications. Therapeutically relevant NADPH oxidase isoforms type 1, 2, 4, and 5 (NOX1, NOX2, NOX4, NOX5). Of note, NOX5 is not present in mice and rats and thus pre-clinically less studied. NOX2, formerly termed gp91phox, has been correlated with many, too many, diseases and is rather relevant as genetic deficiency in chronic granulomatous disease (CGD), treated by gene therapy. Overproduction of ROS through NOX1, NOX4, and NOX5 leads to the indicated diseases states including atherosclerosis (red), a condition where NOX4 is surprisingly protective.
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Affiliation(s)
- Mahmoud H Elbatreek
- Department of Pharmacology and Personalised Medicine, School of MeHNS, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.
| | | | - Harald H H W Schmidt
- Department of Pharmacology and Personalised Medicine, School of MeHNS, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
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Zhang S, Ai HW. A general strategy to red-shift green fluorescent protein-based biosensors. Nat Chem Biol 2020; 16:1434-1439. [PMID: 32929278 PMCID: PMC7669575 DOI: 10.1038/s41589-020-0641-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/06/2020] [Indexed: 11/08/2022]
Abstract
Compared with green fluorescent protein-based biosensors, red fluorescent protein (RFP)-based biosensors are inherently advantageous because of reduced phototoxicity, decreased autofluorescence and enhanced tissue penetration. However, existing RFP-based biosensors often suffer from small dynamic ranges, mislocalization and undesired photoconversion. In addition, the choice of available RFP-based biosensors is limited, and development of each biosensor requires substantial effort. Herein, we describe a general and convenient method, which introduces a genetically encoded noncanonical amino acid, 3-aminotyrosine, to the chromophores of green fluorescent protein-like proteins and biosensors for spontaneous and efficient green-to-red conversion. We demonstrated that this method could be used to quickly expand the repertoire of RFP-based biosensors. With little optimization, the 3-aminotyrosine-modified biosensors preserved the molecular brightness, dynamic range and responsiveness of their green fluorescent predecessors. We further applied spectrally resolved biosensors for multiplexed imaging of metabolic dynamics in pancreatic β-cells.
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Affiliation(s)
- Shen Zhang
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, Charlottesville, VA, USA
| | - Hui-Wang Ai
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, Charlottesville, VA, USA.
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Regulation of Metabolic Processes by Hydrogen Peroxide Generated by NADPH Oxidases. Processes (Basel) 2020. [DOI: 10.3390/pr8111424] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hydrogen peroxide (H2O2) is an important oxidizing molecule that regulates the metabolisms of aerobic organisms. Redox signaling comprises physiological oxidative stress (eustress), while excessive oxidative stress causes damage to molecules. The main enzymatic generators of H2O2 are nicotinamide adenine dinucleotide phosphate oxidases or NADPH oxidases (NOXs) and mitochondrial respiratory chains, as well as various oxidases. The NOX family is constituted of seven enzyme isoforms that produce a superoxide anion (O2−), which can be converted to H2O2 by superoxide dismutase or spontaneously. H2O2 passes through the membranes by some aquaporins (AQPs), known as peroxyporins. It diffuses through cells and tissues to initiate cellular effects, such as proliferation, the recruitment of immune cells, and cell shape changes. Therefore, it has been proposed that H2O2 has the same importance as Ca2+ or adenosine triphosphate (ATP) to act as modulators in signaling and the metabolism. The present overview focuses on the metabolic processes of liver and adipose tissue, regulated by the H2O2 generated by NOXs.
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Lewandowski SL, Cardone RL, Foster HR, Ho T, Potapenko E, Poudel C, VanDeusen HR, Sdao SM, Alves TC, Zhao X, Capozzi ME, de Souza AH, Jahan I, Thomas CJ, Nunemaker CS, Davis DB, Campbell JE, Kibbey RG, Merrins MJ. Pyruvate Kinase Controls Signal Strength in the Insulin Secretory Pathway. Cell Metab 2020; 32:736-750.e5. [PMID: 33147484 PMCID: PMC7685238 DOI: 10.1016/j.cmet.2020.10.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/30/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022]
Abstract
Pancreatic β cells couple nutrient metabolism with appropriate insulin secretion. Here, we show that pyruvate kinase (PK), which converts ADP and phosphoenolpyruvate (PEP) into ATP and pyruvate, underlies β cell sensing of both glycolytic and mitochondrial fuels. Plasma membrane-localized PK is sufficient to close KATP channels and initiate calcium influx. Small-molecule PK activators increase the frequency of ATP/ADP and calcium oscillations and potently amplify insulin secretion. PK restricts respiration by cyclically depriving mitochondria of ADP, which accelerates PEP cycling until membrane depolarization restores ADP and oxidative phosphorylation. Our findings support a compartmentalized model of β cell metabolism in which PK locally generates the ATP/ADP required for insulin secretion. Oscillatory PK activity allows mitochondria to perform synthetic and oxidative functions without any net impact on glucose oxidation. These findings suggest a potential therapeutic route for diabetes based on PK activation that would not be predicted by the current consensus single-state model of β cell function.
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Affiliation(s)
- Sophie L Lewandowski
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Rebecca L Cardone
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Hannah R Foster
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Thuong Ho
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Evgeniy Potapenko
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Chetan Poudel
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Halena R VanDeusen
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sophia M Sdao
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tiago C Alves
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Xiaojian Zhao
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Arnaldo H de Souza
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ishrat Jahan
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Craig J Thomas
- National Center for Advancing Translational Sciences, Rockville, MD 20850, USA
| | - Craig S Nunemaker
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Richard G Kibbey
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA; Department of Cellular & Molecular Physiology, Yale University, New Haven, CT 06520, USA.
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA.
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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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Leguina-Ruzzi A, Vodičková A, Holendová B, Pavluch V, Tauber J, Engstová H, Dlasková A, Ježek P. Glucose-Induced Expression of DAPIT in Pancreatic β-Cells. Biomolecules 2020; 10:biom10071026. [PMID: 32664368 PMCID: PMC7408392 DOI: 10.3390/biom10071026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/14/2022] Open
Abstract
Transcript levels for selected ATP synthase membrane FO-subunits-including DAPIT-in INS-1E cells were found to be sensitive to lowering glucose down from 11 mM, in which these cells are routinely cultured. Depending on conditions, the diminished mRNA levels recovered when glucose was restored to 11 mM; or were elevated during further 120 min incubations with 20-mM glucose. Asking whether DAPIT expression may be elevated by hyperglycemia in vivo, we studied mice with hyaluronic acid implants delivering glucose for up to 14 days. Such continuous two-week glucose stimulations in mice increased DAPIT mRNA by >5-fold in isolated pancreatic islets (ATP synthase F1α mRNA by 1.5-fold). In INS-1E cells, the glucose-induced ATP increment vanished with DAPIT silencing (6% of ATP rise), likewise a portion of the mtDNA-copy number increment. With 20 and 11-mM glucose the phosphorylating/non-phosphorylating respiration rate ratio diminished to ~70% and 96%, respectively, upon DAPIT silencing, whereas net GSIS rates accounted for 80% and 90% in USMG5/DAPIT-deficient cells. Consequently, the sufficient DAPIT expression and complete ATP synthase assembly is required for maximum ATP synthesis and mitochondrial biogenesis, but not for insulin secretion as such. Elevated DAPIT expression at high glucose further increases the ATP synthesis efficiency.
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48
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Kowluru A. Potential roles of PP2A-Rac1 signaling axis in pancreatic β-cell dysfunction under metabolic stress: Progress and promise. Biochem Pharmacol 2020; 180:114138. [PMID: 32634437 DOI: 10.1016/j.bcp.2020.114138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 12/16/2022]
Abstract
Recent estimates by the International Diabetes Federation suggest that the incidence of diabetes soared to an all-time high of 463 million in 2019, and the federation predicts that by 2045 the number of individuals afflicted with this disease will increase to 700 million. Therefore, efforts to understand the pathophysiology of diabetes are critical for moving toward the development of novel therapeutic strategies for this disease. Several contributors (oxidative stress, endoplasmic reticulum stress and others) have been proposed for the onset of metabolic dysfunction and demise of the islet β-cell leading to the pathogenesis of diabetes. Existing experimental evidence revealed sustained activation of PP2A and Rac1 in pancreatic β-cells exposed to metabolic stress (diabetogenic) conditions. Evidence in a variety of cell types implicates modulatory roles for specific signaling proteins (α4, SET, nm23-H1, Pak1) in the functional regulation of PP2A and Rac1. In this Commentary, I overviewed potential cross-talk between PP2A and Rac1 signaling modules in the onset of metabolic dysregulation of the islet β-cell leading to impaired glucose-stimulated insulin secretion (GSIS), loss of β-cell mass and the onset of diabetes. Potential knowledge gaps and future directions in this fertile area of islet biology are also highlighted. It is hoped that this Commentary will provide a basis for future studies toward a better understanding of roles of PP2A-Rac1 signaling module in pancreatic β-cell dysfunction, and identification of therapeutic targets for the treatment of islet β-cell dysfunction in diabetes.
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Affiliation(s)
- Anjaneyulu Kowluru
- Biomedical Laboratory Research Service, John D. Dingell VA Medical Center and Departments of Pharmaceutical Sciences and Internal Medicine, Wayne State University, Detroit, MI 48201, USA.
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