PT  - JOURNAL ARTICLE
AU  - Yaling Liu
AU  - Liqun Yang
AU  - Jiemin Yin
AU  - Diansan Su
AU  - Zhiying Pan
AU  - Peiying Li
AU  - Xiaodong Wang
TI  - MicroRNA-15b deteriorates hypoxia/reoxygenation-induced cardiomyocyte apoptosis by downregulating Bcl-2 and MAPK3
AID  - 10.1136/jim-2017-000485
DP  - 2017 Aug 14
TA  - Journal of Investigative Medicine
PG  - jim-2017-000485
4099  - http://hw-f5-jim.highwire.org/content/early/2017/08/16/jim-2017-000485.short
4100  - http://hw-f5-jim.highwire.org/content/early/2017/08/16/jim-2017-000485.full
AB  - To investigate the role of miRNA-15b in cardiomyocyte apoptosis after ischemia reperfusion injury in acute myocardial infarction (AMI), we conducted the AMI rat model by using left anterior descending ligation and performed hypoxia/reoxygenation experiments in H9c2 cells. MiRNA-15b was measured by quantitative reverse transcription PCR (qRT-PCR). Cardiomyocyte apoptosis was determined by terminal deoxynucleotide transferase dUTP nick end labeling staining. Synthesized miRNA-15b mimic and inhibitor were transfected into H9c2 cells by Lipofectamine regent. RNA expression of B cell lymphoma/leukemia-2 (Bcl-2) and mitogen-activated protein kinase 3 (MAPK3) was examined by qRT-PCR and their protein expression was determined by western blot. Ischemia reperfusion increased miRNA-15b expression in the ischemic rat heart and resulted more severe cardiomyocytes apoptosis. In H9c2 cells, hypoxia/reoxygenation induced increased miRNA-15b expression and augmented cardiomyocyte apoptosis observed at 24 hours after 24-hour hypoxia. Compared with the vehicle group, miRNA-15b mimic further raised miRNA-15b level and increased cardiomyocyte apoptosis, whereas miRNA-15b inhibitor suppressed miRNA-15b expression and protected cardiomyocytes from apoptosis. Although the mRNA expression of the target genes Bcl-2 and MAPK3 was not changed significantly, the protein expression of these two genes were markedly reduced after miRNA-15b mimic treatment and significantly increased after transfected with miRNA-15b inhibitors. In conclusion, miRNA-15b deteriorates cardiomyocyte apoptosis by post-transcriptionally downregulating the expression of Bcl-2 and MAPK3.