生脉散通过miR-199a/HIF-1α通路改善阿霉素心肌病能量代谢的作用及机制研究

Doxorubicin induced cardiomyopathy is a serious complication of doxorubicin treatment, which hinders its clinical use. As a key factor of energy metabolism homeostasis, HIF-1α can down-regulate the activity of PDHc by activating PDK, thereby influencing the glycolysis and oxidative phosphorylation. And the expression of HIF-1α is negatively regulated by miR-199a. Shengmaisan, a Chinese Traditional Medicine, could alleviate the cardiotoxicity of doxorubicin but in-depth mechanism remains to be unclear. By metabonomics technology we previously found Shengmaisan could improve multiple energy metabolites of rats with doxorubicin induced cardiomyopathy. Meanwhile, our preliminary experiments found Shengmaisan could change the expressions of miR-199a, HIF-1α and PDK4. Thus, we put forward the hypothesis that Shengmaisan increases PDHc activity by up-regulating miR-199a and down-regulating HIF-1α/PDK4, thereby improving myocardial energy metabolism in rats with doxorubicin induced cardiomyopathy. Thus, in the present study we plan to establish a rat model of doxorubicin induced cardiomyopathy and cardiomyocyte toxicity model, observing the protective effects of Shengmaisan, and its impacts on the expressions of mitochondria, acetyl coenzyme A and ATP. Further, by gene silencing of miR-199a, to explore how Shengmaisan affects miR-199a and downstream HIF-1α/PDK4/PDHc pathway, thereby improves energy metabolism of doxorubicin induced cardiomyopathy.

阿霉素心肌病是阿霉素化疗的致命并发症，存在严重心肌代谢紊乱。HIF-1α是维持能量代谢稳态的关键因子之一，通过PDK/PDHc影响能量代谢，而HIF-1α表达受miR-199a负调控。生脉散能缓解阿霉素心脏毒性，但机制尚未明确。我们前期通过代谢组学技术发现生脉散改善了阿霉素心肌病大鼠多种能量代谢分子表达。同时预实验初步发现生脉散可上调miR-199a并抑制HIF-1α和PDK4表达。由此，我们提出假设，生脉散通过促进miR-199a表达，缓解HIF-1α/PDK4对PDHc的抑制，从而改善阿霉素心肌病大鼠心肌能量代谢。因此，本项目首先建立阿霉素心肌病动物及细胞模型，检测生脉散对心肌乙酰CoA、ATP和线粒体的影响，观察其对心肌能量代谢的作用。进而通过基因沉默下调miR-199a表达，探讨生脉散通过干预miR-199a影响HIF-1α/PDK4/PDHc通路，改善阿霉素心肌病能量代谢的机制。

作为阿霉素化疗的致命并发症，阿霉素心肌病存在着严重的心肌能量代谢紊乱。HIF-1α是维持能量代谢稳态的关键因子之一，可影响糖酵解和氧化磷酸化，其表达受miR-199a负调控。生脉散能缓解阿霉素心脏毒性，但机制尚未明确。本项目首先从动物层面证实了生脉散能改善阿霉素心肌病大鼠的心肌能量代谢，然后从细胞和分子层面上明确了生脉散通过上调miR-199a表达，抑制HIF-1α及下游的PDK4，从而恢复了PDHc活性，促进了氧化磷酸化，改善了阿霉素介导的心肌能量代谢紊乱。这为生脉散治疗阿霉素心肌病提供新的理论基础和依据，为中医药防治阿霉素毒性研究提供了新的思路和探索。