S1PR1/3-RSK4介导的心脏微血管内皮细胞老化在糖尿病心脏病后期的重要作用

Epidemiology showed the cardiac microvascular injury is a key factor of prognosis for diabetic ischemic heart disease, which is characterized as cellular apoptosis regulated by S1PR1/3-PKCβⅡdependent pathway ( PLoS ONE. 2012). However, our follow-up research found that after 16 weeks, the cardiac function of diabetic rats continued to decline without obvious progress of apoptosis, which indicated.the presence of other factors regulating the disease. And our cellular preliminary experiment demonstrated that after subcultured to 5th generation under high glucose medium, the cardiac microvascular endothelial cell apoptosis also changed little while senescence kept intensified tendency accompanied with increased RSK4 expression. These all suggested there may be a closed relationship among RSK4, senescence and diabetic heart disease. In addition, the phenomena above could be inhibited by S1PR1/3 agonist FTY720, which suggested the relationship between S1PR1/3 and RSK4 as well as the clues in literature. In brief, all evidences implicit that S1PR1/3 medicate cellular senescence through RSK4, which make great contributions to cardiac microvascular injury and cardiac function in the later stage of diabetic heart disease. Our research will be helpful to provide a theoretical basis for the treatment on diabetic heart disease.

流行病学显示心脏微血管损伤是糖尿病心脏病预后关键事件。我们已证明糖尿病大鼠12周时，S1PR1/3通过PKCβⅡ调控细胞凋亡，导致心脏微血管损伤(PLoS ONE.2012)。但后续实验提示糖尿病16周后，心脏细胞凋亡未显著进展，心功能仍持续下降，提示糖尿病心脏病后期存在凋亡以外的其他调控因素。文献提示细胞老化可能是心脏损伤的重要原因。而我们细胞预实验发现，高糖环境下心脏微血管内皮细胞传至第五代后，凋亡变化亦不明显（与动物实验一致），但细胞老化持续加剧，并伴RSK4表达增加，提示RSK4、细胞老化及糖尿病心脏病三者密切相关。而S1PR1/3激动剂FTY720可抑制上述现象，结合文献报道S1PR1/3下游信号与RSK4多有交叉， 进一步坚定本研究假说，即：S1PR1/3通过RSK4调控细胞老化，进而影响糖尿病后期心脏微血管病变及心功能。本研究将为糖尿病心脏病后期防治新靶点的探索提供理论基础。

本研究与申请书原计划一致，从现象到机制，从整体组织到细胞和分子水平逐层验证S1PR1/3及RSK4在糖尿病心脏微血管内皮细胞老化调节以及心脏损伤与保护中的重要作用，并力图阐明二者之间可能存在的上下游关系，希望能够丰富糖尿病心脏病发生发展的理论基础，为改善糖尿病心脏病患者的预后提供新的思路。本项目已按照原计划通过3年分别完成了：1）在动物整体水平明确心脏微血管内皮细胞老化与糖尿病心脏损伤的相关性，进而初步探索S1PR1/3及RSK4与上述二者的密切关系；2）在细胞及分子水平通过 FTY720的药物干预及基因技术对比，确定S1PR1/3在糖尿病心脏微血管内皮细胞老化中的重要作用以及内在作用模式，明确FTY720潜在延缓/抑制细胞老化的治疗作用；3）借助基因技术进一步验证，RSK4是糖尿病心脏微血管内皮细胞老化过程中的关键分子，最终完善S1PR1/3-RSK4信号通路在糖尿病心脏微血管内皮细胞老化调控中的重要作用；