Differentially expressed microRNAs and their target genes in the hearts of streptozotocin-induced diabetic mice

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.