title: Methylene blue decreases mitochondrial lysine acetylation in the diabetic heart.
abstract: Diabetic cardiomyopathy is preceded by mitochondrial alterations, and progresses to heart failure. We studied whether treatment with methylene blue (MB), a compound that was reported to serve as an alternate electron carrier within the mitochondrial electron transport chain (ETC), improves mitochondrial metabolism and cardiac function in type 1 diabetes. MB was administered at 10 mg/kg/day to control and diabetic rats. Both echocardiography and hemodynamic studies were performed to assess cardiac function. Mitochondrial studies comprised the measurement of oxidative phosphorylation and specific activities of fatty acid oxidation enzymes. Proteomic studies were employed to compare the level of lysine acetylation on cardiac mitochondrial proteins between the experimental groups. We found that MB facilitates NADH oxidation, increases NAD+, and the activity of deacetylase Sirtuin 3, and reduces protein lysine acetylation in diabetic cardiac mitochondria. We identified that lysine acetylation on 83 sites in 34 proteins is lower in the MB-treated diabetic group compared to the same sites in the untreated diabetic group. These changes occur across critical mitochondrial metabolic pathways including fatty acid transport and oxidation, amino acid metabolism, tricarboxylic acid cycle, ETC, transport, and regulatory proteins. While the MB treatment has no effect on the activities of acyl-CoA dehydrogenases, it decreases 3-hydroxyacyl-CoA dehydrogenase activity and long-chain fatty acid oxidation, and improves cardiac function. Providing an alternative route for mitochondrial electron transport is a novel therapeutic approach to decrease lysine acetylation, alleviate cardiac metabolic inflexibility, and improve cardiac function in diabetes.
authors.affiliation: Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Berthiaume
authors.affiliation: Department of Foundational Sciences, Central Michigan University College of Medicine, 2630 Denison Drive, Research Building Room 105, Mount Pleasant, MI, 48858, USA.
authors.forename: Chia-Heng
authors.initials: CH
authors.lastname: Hsiung
authors.affiliation: Department of Foundational Sciences, Central Michigan University College of Medicine, 2630 Denison Drive, Research Building Room 105, Mount Pleasant, MI, 48858, USA.
authors.forename: Alison B
authors.initials: AB
authors.lastname: Austin
authors.affiliation: Department of Foundational Sciences, Central Michigan University College of Medicine, 2630 Denison Drive, Research Building Room 105, Mount Pleasant, MI, 48858, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: McBrayer
authors.affiliation: Department of Foundational Sciences, Central Michigan University College of Medicine, 2630 Denison Drive, Research Building Room 105, Mount Pleasant, MI, 48858, USA.
authors.forename: Mikayla M
authors.initials: MM
authors.lastname: Depuydt
authors.affiliation: Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Margaret P
authors.initials: MP
authors.lastname: Chandler
authors.affiliation: Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Masaru
authors.initials: M
authors.lastname: Miyagi
authors.affiliation: Department of Foundational Sciences, Central Michigan University College of Medicine, 2630 Denison Drive, Research Building Room 105, Mount Pleasant, MI, 48858, USA. rosca1g@cmich.edu.
authors.forename: Mariana G
authors.identifier: http://orcid.org/0000-0003-3605-9787
authors.initials: MG
authors.lastname: Rosca
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D058065:Diabetic Cardiomyopathies / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology*; D008929:Mitochondria, Heart / Q000378:metabolism*; D051381:Rats; D011917:Rats, Inbred Lew
chemical_list: D008239:Lysine; D008751:Methylene Blue
keywords: Cardiomyopathy; Diabetes; Fatty acid oxidation; Lysine acetylation; Methylene blue; Mitochondria