Diabetes Exacerbates Myocardial Ischemia Reperfusion Injury by Down-Regulation of MicroRNA and Up-Regulation of O-GlcNAcylation
Dandan Wang, Xiaoyue Hu, Seung Hee Lee, Feng Chen, Kai Jiang, Zizhuo Tu, Zejian Liu, Jing Du, Li Wang, Chaoying Yin, Yu Liao, Hongcai Shang, Kathleen A. Martin, Raimund I. Herzog, Lawrence H. Young, Li Qian, John Hwa and Yaozu Xiang
miR-24 Regulates OGT and ATG4A to Play Cardioprotective Effects
Sequence alignment of miR-24 targeting sites on OGT (A) and ATG4A (B) 3ʹUTR among mammals based on the Targetscan database information. (C) miR-24 inhibited luciferase activity of WT 3ʹUTR of OGT, ATG4A, and BIM, but exhibited no effect on luciferase activity of each mutant 3ʹUTR. The assays were performed in triplicate from 3 independent experiments. (D) The change in intracellular miR-24 levels when cardiomyocytes were transfected with miR-24 mimics and performed in triplicate from 3 independent experiments. (E) (Top) Representative Western blot analyses of OGT, ATG4A, and BIM expression in response to miR-24 overexpression in cardiomyocytes, normalized to HSP90 and actin. (Bottom) Cardiomyocytes were transfected with miR-24 mimic (Ambion mirVana miRNA mimic) or negative control via Lipofectamine RNAiMAX Transfection Reagent. A total of 48 h after transfection, cells were treated with 100 nmol/l insulin for another 1 h before harvested. The expression of OGT was analyzed by western blot. (F) OGT expression and O-GlcNAcylation of heart lysates from WT mice or mice with cardiomyocyte-specific overexpression of miR-24, and heart lysates from in db/db mice with control or miR-24 mimic (Life Technologies, 5 mg/kg) delivery. Abbreviations as in Figure 1.