抗心肌缺血再灌注损伤新机制：SMP30介导姜黄素心脏保护作用的关键信号通路研究

Curcumin confers significant cardioprotective effect by reducing myocardial ischemia reperfusion injury (IRI), which shows great prospects in clinic. However, the underlying mechanism has not been fully elucidated which limits its clinical application. We have previously demonstrated that curcumin treatment conferred cardioprotective effect by activating SIRT1 signaling. However, the up and down stream signaling pathway of SIRT1 is unknown. Senescence marker protein 30 (SMP30) has been proved to be a key and novel anti-apoptotic molecule, which plays an important role in cardiovascular disease. However, whether SMP30 participate in IRI has not been elucidated. We have previously found that curcumin reduced IRI by up-regulation of SMP30, suggesting that SMP30 maybe a novel cardioprotective molecule. Previous studies indicated that PKC is the down-stream target of SMP30. Activation of PKC-ε by ischemia preconditioning conferred neuroprotective effect by up-regulating SIRT1 signaling. Therefore, we hypothesized that activation of SMP30, PKC-ε and SIRT1 signaling pathway against myocardial ischemia reperfusion injury. SMP30 knockout and transgenic mice, isolated and in vivo rat hearts, and cardiomyocytes will be used in this project to study the role of SMP30 in myocardial IRI and to explore the interaction or up-downstream relationships between SMP30 and PKC-ε/SIRT1 in myocardial IRI and cardialprotection of curcumin. This project would draw new targets of anti-myocardial IRI, and provide the theoretical basis for more effective methods of myocardial protection .

姜黄素具有显著抗缺血再灌注损伤（IRI）心脏保护作用，极具开发前景，但作用机制尚未完全阐明，临床应用受限。我们首先发现SIRT1在姜黄素抗心脏IRI中发挥重要调控作用但上下游信号通路未知。与SIRT1同为衰老相关分子的衰老标记蛋白30（SMP30）被证实为全新的抗凋亡关键分子，但SMP30是否参与调控心肌IRI尚无报道。预实验发现姜黄素减轻IRI伴有SMP30表达增加，提示SMP30可能是抗心肌IRI新分子。文献报道PKC是SMP30抗凋亡途径下游分子。缺血预处理可激活PKC-ε上调SIRT1发挥脑保护作用。因此我们提出科学假说：激活SMP30经PKC-ε、SIRT1关键信号通路是抗心肌IRI新机制。本项目拟采用SMP30基因敲除和转基因小鼠，从在体、离体、细胞水平研究证实该假说并阐明姜黄素通过SMP30发挥心脏保护作用新机制，为研发以SMP30为靶点的全新心肌保护方法奠定理论和实验基础。

沉默信息调控因子1（SIRT1）在抗心脏缺血再灌注损伤（IRI）中发挥重要调控作用但上下游信号通路未知。与SIRT1同为衰老相关分子的衰老标记蛋白30（SMP30）被证实为全新的抗凋亡关键分子，但SMP30是否参与调控心肌IRI尚无报道。通过体内和体外研究，我们证实SMP30功能障碍是介导心肌 IRI的关键机制，上调SMP30表达明显抑制心肌IRI，而下调SMP30表达明显加剧心肌IRI。进一步地，我们证实PKC-ε和SIRT1是SMP30的下游分子，且介导了SMP30的保护作用。在该课题的资助下，我们进一步实验发现：1）SMP30是介导褪黑素抵抗心肌IRI的关键靶点，且SIRT1为其下游信号；2）PKC-ε是介导褪黑素抵抗心肌IRI的关键靶点，且SIRT1为其下游信号；3）SIRT1是介导和厚朴酚抗糖尿病状态下心肌IRI的关键靶点。综上，我们通过大量的实验，证实了SMP30-PKCε-SIRT1信号通路在心肌IRI中的关键作用，并证实多种药物可通过激活该通路发挥抗心肌IRI作用。本研究阐明了心肌IRI的具体分子机制，为临床上防治心肌IRI提供了新的治疗靶点和方案。