The Role of Metabolic Flexibility in the Regulation of the DNA Damage Response by Nitric Oxide

ABSTRACTIn this report, we show that nitric oxide suppresses DNA damage response (DDR) signaling in the pancreatic β-cell line INS 832/13 and rat islets by inhibiting intermediary metabolism. Nitric oxide is known to inhibit complex IV of the electron transport chain and aconitase of the Krebs cycle. Non-β cells compensate by increasing glycolytic metabolism to maintain ATP levels; however, β cells lack this metabolic flexibility, resulting in a nitric oxide-dependent decrease in ATP and NAD+. Like nitric oxide, mitochondrial toxins inhibit DDR signaling in β cells by a mechanism that is associated with a decrease in ATP. Non-β cells compensate for the effects of mitochondrial toxins with an adaptive shift to glycolytic ATP generation that allows for DDR signaling. Forcing non-β cells to derive ATP via mitochondrial respiration (replacing glucose with galactose in the medium) and glucose deprivation sensitizes these cells to nitric oxide-mediated inhibition of DDR signaling. These findings indicate that metabolic flexibility is necessary to maintain DDR signaling under conditions in which mitochondrial oxidative metabolism is inhibited and support the inhibition of oxidative metabolism (decreased ATP) as one protective mechanism by which nitric oxide attenuates DDR-dependent β-cell apoptosis.

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Nitric Oxide Suppresses β-Cell Apoptosis by Inhibiting the DNA Damage Response

Molecular and Cellular Biology ◽

10.1128/mcb.00262-16 ◽

2016 ◽

Vol 36 (15) ◽

pp. 2067-2077 ◽

Cited By ~ 12

Author(s):

Bryndon J. Oleson ◽

Katarzyna A. Broniowska ◽

Aaron Naatz ◽

Neil Hogg ◽

Vera L. Tarakanova ◽

...

Keyword(s):

Nitric Oxide ◽

Dna Damage ◽

Cell Survival ◽

Dna Damage Response ◽

Cell Apoptosis ◽

Β Cells ◽

Β Cell ◽

Pancreatic Β Cells ◽

Damage Response ◽

Induced Apoptosis

Nitric oxide, produced in pancreatic β cells in response to proinflammatory cytokines, plays a dual role in the regulation of β-cell fate. While nitric oxide induces cellular damage and impairs β-cell function, it also promotes β-cell survival through activation of protective pathways that promote β-cell recovery. In this study, we identify a novel mechanism in which nitric oxide prevents β-cell apoptosis by attenuating the DNA damage response (DDR). Nitric oxide suppresses activation of the DDR (as measured by γH2AX formation and the phosphorylation of KAP1 and p53) in response to multiple genotoxic agents, including camptothecin, H2O2, and nitric oxide itself, despite the presence of DNA damage. While camptothecin and H2O2both induce DDR activation, nitric oxide suppresses only camptothecin-induced apoptosis and not H2O2-induced necrosis. The ability of nitric oxide to suppress the DDR appears to be selective for pancreatic β cells, as nitric oxide fails to inhibit DDR signaling in macrophages, hepatocytes, and fibroblasts, three additional cell types examined. While originally described as the damaging agent responsible for cytokine-induced β-cell death, these studies identify a novel role for nitric oxide as a protective molecule that promotes β-cell survival by suppressing DDR signaling and attenuating DNA damage-induced apoptosis.

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Nitric Oxide Prevents β-Cell Apoptosis Via Inhibition of the DNA Damage Response

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2016.10.114 ◽

2016 ◽

Vol 100 ◽

pp. S43-S44

Author(s):

Bryndon J. Oleson ◽

Katarzyna A. Broniowska ◽

Aaron Naatz ◽

Neil Hogg ◽

Vera L. Tarakanova ◽

...

Keyword(s):

Nitric Oxide ◽

Dna Damage ◽

Dna Damage Response ◽

Cell Apoptosis ◽

Β Cell ◽

Damage Response

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Role of Protein Phosphatase 1 and Inhibitor of Protein Phosphatase 1 in Nitric Oxide–Dependent Inhibition of the DNA Damage Response in Pancreatic β-Cells

Diabetes ◽

10.2337/db17-1062 ◽

2018 ◽

Vol 67 (5) ◽

pp. 898-910 ◽

Cited By ~ 4

Author(s):

Bryndon J. Oleson ◽

Aaron Naatz ◽

Sarah C. Proudfoot ◽

Chay Teng Yeo ◽

John A. Corbett

Keyword(s):

Nitric Oxide ◽

Dna Damage ◽

Dna Damage Response ◽

Protein Phosphatase ◽

Protein Phosphatase 1 ◽

Β Cells ◽

Pancreatic Β Cells ◽

Damage Response ◽

Dependent Inhibition

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2118-P: Regulation of Ataxia-Telangiectasia and Rad3-Related (ATR)–Dependent DNA Damage Response by Nitric Oxide in ß-Cells

Diabetes ◽

10.2337/db20-2118-p ◽

2020 ◽

Vol 69 (Supplement 1) ◽

pp. 2118-P

Author(s):

CHAY TENG YEO ◽

BRYNDON OLESON ◽

JOHN A. CORBETT ◽

JAMIE K. SCHNUCK

Keyword(s):

Nitric Oxide ◽

Dna Damage ◽

Dna Damage Response ◽

Ataxia Telangiectasia ◽

Damage Response

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TCF19 Impacts a Network of Inflammatory and DNA Damage Response Genes in the Pancreatic β-Cell

Metabolites ◽

10.3390/metabo11080513 ◽

2021 ◽

Vol 11 (8) ◽

pp. 513

Author(s):

Grace H. Yang ◽

Danielle A. Fontaine ◽

Sukanya Lodh ◽

Joseph T. Blumer ◽

Avtar Roopra ◽

...

Keyword(s):

Gene Expression ◽

Dna Damage ◽

Dna Damage Response ◽

Association Studies ◽

Cell Cycle Gene ◽

Genome Wide Association Studies ◽

Β Cell ◽

Nucleotide Incorporation ◽

Damage Response ◽

The Impact

Transcription factor 19 (TCF19) is a gene associated with type 1 diabetes (T1DM) and type 2 diabetes (T2DM) in genome-wide association studies. Prior studies have demonstrated that Tcf19 knockdown impairs β-cell proliferation and increases apoptosis. However, little is known about its role in diabetes pathogenesis or the effects of TCF19 gain-of-function. The aim of this study was to examine the impact of TCF19 overexpression in INS-1 β-cells and human islets on proliferation and gene expression. With TCF19 overexpression, there was an increase in nucleotide incorporation without any change in cell cycle gene expression, alluding to an alternate process of nucleotide incorporation. Analysis of RNA-seq of TCF19 overexpressing cells revealed increased expression of several DNA damage response (DDR) genes, as well as a tightly linked set of genes involved in viral responses, immune system processes, and inflammation. This connectivity between DNA damage and inflammatory gene expression has not been well studied in the β-cell and suggests a novel role for TCF19 in regulating these pathways. Future studies determining how TCF19 may modulate these pathways can provide potential targets for improving β-cell survival.

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Inhibition of oxidative metabolism by nitric oxide restricts EMCV replication selectively in pancreatic beta-cells

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.015893 ◽

2020 ◽

Vol 295 (52) ◽

pp. 18189-18198

Author(s):

Joshua D. Stafford ◽

Chay Teng Yeo ◽

John A. Corbett

Keyword(s):

Nitric Oxide ◽

Insulin Secretion ◽

Oxidative Metabolism ◽

Mitochondrial Respiration ◽

Pancreatic Beta Cells ◽

Encephalomyocarditis Virus ◽

Β Cells ◽

Β Cell ◽

Atp Levels ◽

Mitochondrial Oxidative Metabolism

Environmental factors, such as viral infection, are proposed to play a role in the initiation of autoimmune diabetes. In response to encephalomyocarditis virus (EMCV) infection, resident islet macrophages release the pro-inflammatory cytokine IL-1β, to levels that are sufficient to stimulate inducible nitric oxide synthase (iNOS) expression and production of micromolar levels of the free radical nitric oxide in neighboring β-cells. We have recently shown that nitric oxide inhibits EMCV replication and EMCV-mediated β-cell lysis and that this protection is associated with an inhibition of mitochondrial oxidative metabolism. Here we show that the protective actions of nitric oxide against EMCV infection are selective for β-cells and associated with the metabolic coupling of glycolysis and mitochondrial oxidation that is necessary for insulin secretion. Inhibitors of mitochondrial respiration attenuate EMCV replication in β-cells, and this inhibition is associated with a decrease in ATP levels. In mouse embryonic fibroblasts (MEFs), inhibition of mitochondrial metabolism does not modify EMCV replication or decrease ATP levels. Like most cell types, MEFs have the capacity to uncouple the glycolytic utilization of glucose from mitochondrial respiration, allowing for the maintenance of ATP levels under conditions of impaired mitochondrial respiration. It is only when MEFs are forced to use mitochondrial oxidative metabolism for ATP generation that mitochondrial inhibitors attenuate viral replication. In a β-cell selective manner, these findings indicate that nitric oxide targets the same metabolic pathways necessary for glucose stimulated insulin secretion for protection from viral lysis.

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THU-447-DNA damage response CHK2 activates senescence cellular program and supports oxidative metabolism to drive hepatocellular carcinoma development

Journal of Hepatology ◽

10.1016/s0618-8278(19)30694-2 ◽

2019 ◽

Vol 70 (1) ◽

pp. e355

Author(s):

Matteo Lulli ◽

Lorenzo Cavallini ◽

Laura Gragnani ◽

Caecilia Sukowati ◽

Tommaso Mello ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Dna Damage ◽

Dna Damage Response ◽

Oxidative Metabolism ◽

Damage Response

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Loss of Deubiquitinase USP1 Blocks Pancreatic β-Cell Apoptosis by Inhibiting DNA Damage Response

iScience ◽

10.1016/j.isci.2018.02.003 ◽

2018 ◽

Vol 1 ◽

pp. 72-86 ◽

Cited By ~ 3

Author(s):

Kanaka Durga Devi Gorrepati ◽

Blaz Lupse ◽

Karthika Annamalai ◽

Ting Yuan ◽

Kathrin Maedler ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Cell Apoptosis ◽

Pancreatic Β Cell ◽

Β Cell ◽

Damage Response

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Inhibition of mitochondrial oxidative metabolism attenuates EMCV replication and protects β-cells from virally mediated lysis

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014851 ◽

2020 ◽

Vol 295 (49) ◽

pp. 16655-16664 ◽

Cited By ~ 1

Author(s):

Joshua D. Stafford ◽

Zachary R. Shaheen ◽

Chay Teng Yeo ◽

John A. Corbett

Keyword(s):

Nitric Oxide ◽

Viral Replication ◽

Viral Infection ◽

Oxidative Metabolism ◽

Cell Lysis ◽

Encephalomyocarditis Virus ◽

Dependent Manner ◽

Β Cells ◽

Β Cell ◽

Mitochondrial Oxidative Metabolism

Viral infection is one environmental factor that may contribute to the initiation of pancreatic β-cell destruction during the development of autoimmune diabetes. Picornaviruses, such as encephalomyocarditis virus (EMCV), induce a pro-inflammatory response in islets leading to local production of cytokines, such as IL-1, by resident islet leukocytes. Furthermore, IL-1 is known to stimulate β-cell expression of iNOS and production of the free radical nitric oxide. The purpose of this study was to determine whether nitric oxide contributes to the β-cell response to viral infection. We show that nitric oxide protects β-cells against virally mediated lysis by limiting EMCV replication. This protection requires low micromolar, or iNOS-derived, levels of nitric oxide. At these concentrations nitric oxide inhibits the Krebs enzyme aconitase and complex IV of the electron transport chain. Like nitric oxide, pharmacological inhibition of mitochondrial oxidative metabolism attenuates EMCV-mediated β-cell lysis by inhibiting viral replication. These findings provide novel evidence that cytokine signaling in β-cells functions to limit viral replication and subsequent β-cell lysis by attenuating mitochondrial oxidative metabolism in a nitric oxide–dependent manner.

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