title: MicroRNA-133a regulates DNA methylation in diabetic cardiomyocytes.
abstract: We tested the hypothesis that miR-133a regulates DNA methylation by inhibiting Dnmt-1 (maintenance) and Dnmt-3a and -3b (de novo) methyl transferases in diabetic hearts by using Ins2(+/-) Akita (diabetic) and C57BL/6J (WT), mice and HL1 cardiomyocytes. The specific role of miR-133a in DNA methylation in diabetes was assessed by two treatment groups (1) scrambled, miR-133a mimic, anti-miR-133a, and (2) 5mM glucose (CT), 25 mM glucose (HG) and HG+miR-133a mimic. The levels of miR-133a, Dnmt-1, -3a and -3b were measured by multiplex RT-PCR, qPCR and Western blotting. The results revealed that miR-133a is inhibited but Dnmt-1 and -3b are induced in Akita suggesting that attenuation of miR-133a induces both maintenance (Dnmt-1) - and de novo - methylation (Dnmt-3b) in diabetes. The up regulation of Dnmt-3a in Akita hearts elicits intricate and antagonizing interaction between Dnmt-3a and -3b. In cardiomyocytes, over expression of miR-133a inhibits but silencing of miR-133a induces Dnmt-1, -3a and -3b elucidating the involvement of miR-133a in regulation of DNA methylation. The HG treatment up regulates only Dnmt-1 and not Dnmt-3a and -3b suggesting that acute hyperglycemia triggers only maintenance methylation. The over expression of miR-133a mitigates glucose mediated induction of Dnmt-1 illustrating the role of miR-133a in regulation of DNA methylation in diabetes.
authors: Department of Physiology & Biophysics, School of Medicine, University of Louisville, KY 40202, USA.
authors: Vishalakshi
authors: V
authors: Chavali
authors: Suresh C
authors: SC
authors: Tyagi
authors: Paras K
authors: PK
authors: Mishra
mesh_terms: D000818:Animals; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics*; D019175:DNA Methylation; D000090205:DNA Methyltransferase 3A; D003920:Diabetes Mellitus / Q000235:genetics*; D004195:Disease Models, Animal; D044127:Epigenesis, Genetic; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000201:enzymology / Q000378:metabolism*
chemical_list: C000715535:Dnmt3a protein, mouse; C561967:Ins2 protein, mouse; D007328:Insulin; D035683:MicroRNAs; C517732:Mirn133 microRNA, mouse; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D005947:Glucose