MicroRNA-34a regulates cardiac fibrosis after myocardial infarction by targeting Smad4

作者：Huang Ying; Qi Yuan; Du Jian Qing; Zhang Dai fu^*

来源：Expert Opinion on Therapeutic Targets, 2014, 18(12): 1355-1365.

DOI：10.1517/14728222.2014.961424

• cardiac fibrosis
• fibroblasts
• microRNA-34a
• Smad4
• TGF-beta 1

Background: Although few microRNAs (miRNAs) have been involved in the regulation of post-ischemic cardiac fibrosis, the exact effect and underlying mechanism of miRNAs in cardiac fibrosis remains unclear. Here, we sought to investigate whether microRNA-34 (miR-34) plays a role in the pathogenic development of myocardial fibrosis.
Methods: The myocardial infarction (MI) mice model was induced and cardiac fibroblasts were cultured. Histological analyses, quantitative real-time polymerase chain reaction and Western blotting analysis were used.
Results: We found that the miR-34 cluster, especially miR-34a, was upregulated in the MI heart. In vivo, inhibition of miR-34a reduces the severity of experimental cardiac fibrosis in mice. TGF-beta 1 increased miR-34a expression in cardiac fibroblasts. Overexpressing miR-34a levels increased the profibrogenic activity of TGF-beta 1 in cardiac fibroblast, whereas inhibition miR-34a levels weakened the activity. Finally, we showed that miR-34a's underlying mechanism during cardiac fibrosis occurs through the targeting of Smad4 expression.
Conclusions: Our findings provide evidence that miR-34a plays a critical role in the progression of cardiac tissue fibrosis by directly targeting Smad4, which suggests that miR-34a may be new marker for cardiac fibrosis progression and that inhibition of miR-34a may be a promising strategy in the treatment of cardiac fibrosis.

• 出版日期2014-12