[Show abstract][Hide abstract] ABSTRACT: Cardiac hypertrophy is a key structural feature of diabetic cardiomyopathy in the late stage of diabetes. Recent studies show that microRNAs (miRNAs) are involved in the pathogenesis of cardiac hypertrophy in diabetic mice, but more novel miRNAs remain to be investigated. In this study, diabetic cardiomyopathy, characterized by hypertrophy, was induced in mice by streptozotocin injection. Using microarray analysis of myocardial tissue, we were able to identify changes in expression in 19 miRNA, of which 16 miRNAs were further validated by real-time PCR and a total of 3212 targets mRNA were predicted. Further analysis showed that 31 GO functions and 16 KEGG pathways were enriched in the diabetic heart. Of these, MAPK signaling pathway was prominent. In vivo and in vitro studies have confirmed that three major subgroups of MAPK including ERK1/2, JNK, and p38, are specifically upregulated in cardiomyocyte hypertrophy during hyperglycemia. To further explore the potential involvement of miRNAs in the regulation of glucose-induced cardiomyocyte hypertrophy, neonatal rat cardiomyocytes were exposed to high glucose and transfected with miR-373 mimic. Overexpression of miR-373 decreased the cell size, and also reduced the level of its target gene MEF2C, and miR-373 expression was regulated by p38. Our data highlight an important role of miRNAs in diabetic cardiomyopathy, and implicate the reliability of bioinformatics analysis in shedding light on the mechanisms underlying diabetic cardiomyopathy.
American Journal Of Pathology 06/2011; 179(2):639-50. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Persistent hyperglycemia in diabetic patients has been associated with cardiac hypertrophy, myocardial fibrosis and cardiac dysfunction. However, the underlying mechanisms of this association have yet to be fully elucidated. The aim of this study was to investigate the expression and function of microRNAs (miRNAs) in diabetic cardiomyopathy. miRNA expression profiles were examined by miRNA microarray analysis in heart tissue from streptozotocin (STZ)-induced diabetic mice and non-diabetic mice. The targets of the altered miRNAs were predicted using the Sanger database. Then, the targets RASA1, RAC1, TGFB3 and COL1A1, related to cardiac hypertrophy or myocardial fibrosis, were selected to analyze the miRNA level by real-time reverse transcription (RT-PCR). Gene Ontology (GO) was further applied to describe the function of each miRNA target gene and to elucidate their combined effects in diabetic cardiomyopathy. Up-regulated (n=10) and down-regulated (n=6) miRNAs were identified in diabetic cardiomyopathy. Target genes (n=192) were pooled from the Sanger database. Among the 192 targets, the mRNA expression of RASA1, RAC1, TGFB3 and COL1A1 was increased in diabetic cardiomyopathy. Thirty one GO functions were enriched in diabetic cardiomyopathy. These results demonstrate that miRNAs may mediate cardiac hypertrophy and myocardial fibrosis in diabetic cardiomyopathy via their targets, and provide insights into the pathogenesis of diabetic cardiomyopathy.
Molecular Medicine Reports 4(4):633-40. · 1.17 Impact Factor