标题:
Activation of miR-34a/Sirt1/p66shc pathway contributes to doxorubicin-induced cardiotoxicity
讲者:
唐春梅
单位:
广东省人民医院
播放:
2606
论文摘要:
Aims The co-administration of dexrazoxane (DEX) with anthracyclines is an efficient strategy to relieve anthracyclines-promoted organ damage, however, the molecular mechanisms underlying anthracyclines-induced cardiotoxicity have not been well elucidated. The present study aimed to investigate the pivotal microRNAs (miRNAs) involved in doxorubicin (Dox)-induced cardiotoxicity.
Methods The rats model of cardiotoxicity was established with doxorubicin (Dox) treatment. A cell model of apoptosis was established based on Doxorubicin (Dox)-induced rat cardiomyocyte H9C2 cells. The expression of miRNAs in the myocardium and plasma of rats received Dox treatment was revealed by MiRNA profiling.The apoptotic H9C2 cells was detected by TUNEL assay. Dual luciferase reporter assay was performed to verify the interaction between miR-34a and the 3’UTR of SIRT1. The expression of the related genes at mRNA and protein levels was determined by RT-qPCR and Western blotting, respectively.
Results MiRNA profiling revealed that miRNAs were dysregulated in the myocardium and plasma of rats received Dox treatment. RT-qPCR assay revealed that miR-21, -34a were consistently increased in the myocardium and plasma of Dox-treated rats, but were reversed in rats received Dox plus DEX treatments. MiR-34a, not miR-21, was also observed increased in the plasma of patients with diffuse large B-cell lymphoma (DLBCL) after 9- and 16- week epirubicin therapy. Up-regulation of miR-34a was observed in Dox-induced apoptotic rat cardiomyocyte H9c2 cells. MiR-34a could augment Bax expression, but inhibited Bcl-2 expression, along with the increase of mitochondrial potentials in H9C2 cells. MiR-34a was verified to interact with 3’-UTR of SIRT1 gene and to modulate SirT1 expression post-transcriptionally. In parallel to SiRT1 siRNA, miR-34a could enhance p66shc expression, accompanied by an increase of Bax and a decrease of Bcl-2 in H9c2 cells. Moreover, enforced expression of SirT1 alleviated Dox-induced apoptosis of H9c2 cells, with suppressing expressions of p66shc, Bax and miR-34a, and enhancing Bcl-2 expression. Additionally, we identify NF-kB signaling mediated Dox-induced upregulation of miR-34a in cardiomyocytes.
Conclusion MiR-34a enhances p66shc by targeting SirT1, activation of miR-34a/SirT1/p66shc pathway contributes to Dox-induced cardiotoxicity, and blockage of this pathway represents a potential cardioprotective effect against anthracyclines.