title: P66Shc-Induced MicroRNA-34a Causes Diabetic Endothelial Dysfunction by Downregulating Sirtuin1.
abstract: OBJECTIVE
  Diabetes mellitus causes vascular endothelial dysfunction and alters vascular microRNA expression. We investigated whether endothelial microRNA-34a (miR-34a) leads to diabetic vascular dysfunction by targeting endothelial sirtuin1 (Sirt1) and asked whether the oxidative stress protein p66Shc governs miR-34a expression in the diabetic endothelium.
  
  
  RESULTS
  MiR-34a is upregulated, and Sirt1 downregulated, in aortic endothelium of db/db and streptozotocin-induced diabetic mice. Systemic administration of miR-34a inhibitor, or endothelium-specific knockout of miR-34a, prevents downregulation of aortic Sirt1 and rescues impaired endothelium-dependent aortic vasorelaxation induced by diabetes mellitus. Moreover, overexpression of Sirt1 mitigates impaired endothelium-dependent vasorelaxation caused by miR-34a mimic ex vivo. Systemic infusion of miR-34a inhibitor or genetic ablation of endothelial miR-34a prevents downregulation of endothelial Sirt1 by high glucose. MiR-34a is upregulated, Sirt1 is downregulated, and oxidative stress (hydrogen peroxide) is induced in endothelial cells incubated with high glucose or the free fatty acid palmitate in vitro. Increase of hydrogen peroxide and induction of endothelial miR-34a by high glucose or palmitate in vitro is suppressed by knockdown of p66shc. In addition, overexpression of wild-type but not redox-deficient p66Shc upregulates miR-34a in endothelial cells. P66Shc-stimulated upregulation of endothelial miR-34a is suppressed by cell-permeable antioxidants. Finally, mice with global knockdown of p66Shc are protected from diabetes mellitus-induced upregulation of miR-34a and downregulation of Sirt1 in the endothelium.
  
  
  CONCLUSIONS
  These data show that hyperglycemia and elevated free fatty acids in the diabetic milieu recruit p66Shc to upregulate endothelial miR-34a via an oxidant-sensitive mechanism, which leads to endothelial dysfunction by targeting Sirt1.
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Qiuxia
authors: Q
authors: Li
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Young-Rae
authors: YR
authors: Kim
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Ajit
authors: A
authors: Vikram
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Santosh
authors: S
authors: Kumar
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Modar
authors: M
authors: Kassan
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Mohanad
authors: M
authors: Gabani
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Sang Ki
authors: SK
authors: Lee
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.).
authors: Julia S
authors: JS
authors: Jacobs
authors: From the Cardiovascular Division, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City (Q.L., Y.-R.K., A.V., S.K., M.K., M.G., J.S.J., K.I.); and Department of Sports Science, Chungnam National University, Daejeon, Korea (S.K.L.). kaikobad-irani@uiowa.edu qiuxia-li@uiowa.edu.
authors: Kaikobad
authors: K
authors: Irani
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000201:enzymology / Q000235:genetics; D003925:Diabetic Angiopathies / Q000201:enzymology* / Q000209:etiology / Q000235:genetics / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D004734:Energy Metabolism; D005838:Genotype; D005947:Glucose / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D019308:Palmitic Acid / Q000378:metabolism; D010641:Phenotype; D034622:RNA Interference; D015398:Signal Transduction; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000975:Antioxidants; C522425:MIRN34 microRNA, human; C551848:MIRN34a microRNA, mouse; D035683:MicroRNAs; C528024:SHC1 protein, human; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016159:Tumor Suppressor Protein p53; D014665:Vasodilator Agents; D019308:Palmitic Acid; C447939:SIRT1 protein, human; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; D005947:Glucose
keywords: diabetes mellitus; endothelial dysfunction; microRNA-34a; p66Shc; sirtuin1