Hyperglycemia Acutely Increases Cytosolic Reactive Oxygen Species via O-linked GlcNAcylation and CaMKII Activation in Mouse Ventricular Myocytes. Issue 10 (8th May 2020)

• Record Type: Journal Article
• Authors: Lu, Shan; Liao, Zhandi; Lu, Xiyuan; Katschinski, Dörthe M.; Mercola, Mark; Chen, Ju; Heller Brown, Joan; Molkentin, Jeffery D.; Bossuyt, Julie; Bers, Donald M.
• Is Part Of: Circulation research. Volume 126:Issue 10(2020)
• Publication Date: 2020-05-08
• Subjects: calcium-calmodulin-dependent protein kinase type 2 -- hyperglycemia -- myocytes, cardiac -- oxidation-reduction -- signal transduction; Cardiovascular system -- Periodicals; Blood -- Circulation -- Periodicals; Blood Circulation; Cardiovascular System; Vascular Diseases; Sang -- Circulation -- Périodiques; Appareil cardiovasculaire -- Périodiques; 612.1
• DOI: 10.1161/CIRCRESAHA.119.316288
• Languages: English
• ISSNs: 0009-7330

Abstract

Abstract : Rationale: Diabetes mellitus is a complex, multisystem disease, affecting large populations worldwide. Chronic CaMKII (Ca 2+ /calmodulin-dependent kinase II) activation may occur in diabetes mellitus and be arrhythmogenic. Diabetic hyperglycemia was shown to activate CaMKII by (1) O -linked attachment of N-acetylglucosamine ( O -GlcNAc) at S280 leading to arrhythmia and (2) a reactive oxygen species (ROS)–mediated oxidation of CaMKII that can increase postinfarction mortality. Objective: To test whether high extracellular glucose (Hi-Glu) promotes ventricular myocyte ROS generation and the role played by CaMKII. Methods and Results: We tested how extracellular Hi-Glu influences ROS production in adult ventricular myocytes, using DCF (2′, 7′-dichlorodihydrofluorescein diacetate) and genetically targeted Grx-roGFP2 redox sensors. Hi-Glu (30 mmol/L) significantly increased the rate of ROS generation—an effect prevented in myocytes pretreated with CaMKII inhibitor KN-93 or from either global or cardiac-specific CaMKIIδ KO (knockout) mice. CaMKII KO or inhibition also prevented Hi-Glu–induced sarcoplasmic reticulum Ca 2+ release events (Ca 2+ sparks). Thus, CaMKII activation is required for Hi-Glu–induced ROS generation and sarcoplasmic reticulum Ca 2+ leak in cardiomyocytes. To test the involvement of O -GlcNAc–CaMKII pathway, we inhibited GlcNAcylation removal by Thiamet G (ThmG), which mimicked the Hi-Glu–induced ROS production. Conversely, inhibition of GlcNAcylation (OSMI-1 [(αR)-α-[[(1, 2-dihydro-2-oxo-6-quinolinyl)sulfonyl]amino]-N-(2-furanylmethyl)-2-methoxy-N-(2-thienylmethyl)-benzeneacetamide]) prevented ROS induction in response to either Hi-Glu or ThmG. Moreover, in a CRSPR-based knock-in mouse in which the functional GlcNAcylation site on CaMKIIδ was ablated (S280A), neither Hi-Glu nor ThmG induced myocyte ROS generation. So CaMKIIδ-S280 is required for the Hi-Glu–induced (and GlcNAc dependent) ROS production. To identify the ROS source(s), we used different inhibitors of NOX (NADPH oxidase) 2 (Gp91ds-tat peptide), NOX4 (GKT137831), mitochondrial ROS (MitoTempo), and NOS (NO synthase) pathway inhibitors (L-NAME, L-NIO, and L-NPA). Only NOX2 inhibition or KO prevented Hi-Glu/ThmG–induced ROS generation. Conclusions: Diabetic hyperglycemia induces acute cardiac myocyte ROS production by NOX2 that requires O -GlcNAcylation of CaMKIIδ at S280. This novel ROS induction may exacerbate pathological consequences of diabetic hyperglycemia. Abstract : Supplemental Digital Content is available in the text.