mTOR信号调控血管平滑肌细胞衰老及脂联素的干预作用

Vascular aging can change the onset thresholds, process and severity of a variety of cardiovascular diseases. Overbalanced or accelerated senescence of vascular smooth muscle cells (VSMCs)is found to be one of the main contributors behind vascular aging. Recent study found that rapamycin can significantly extend lifespan and delay the onset of aging-related deseases via inhibiting the mammalian target of rapamycin (mTOR), but the work on translating it into clinical application is blocked. The applicant intends to explore the link between vascular aging and mTOR. Our preliminary results demonstrate that mTOR regulates the vascular calcification that results from the osteoblastic differentiation of VSMCs. This process can be alleviated by adiponectin.It is well know that vascular calcification is the most important characteristics of vascular aging . The constructed models in pre-experiment showed that mTOR was up-regulated in the replicative senescence of VSMCs and the premature senescence induced by high glucose. The pre-experiments also revealed that adiponectin can down-regulate the expression of mTOR in the premature senescence of VSMCs induced by high glucose, decrease the activity of senescence-associated β-galactosidase, and decrease the staining positive rate. Based on these results, the applicant puts forword the hypothesis: mTOR regulates VSMCs senescence; adiponectin can delay the premature senescence of VSMCs induced by high glucose through inhibiting mTOR. The applicant will test the hypothesis using the two types of VSMCs senescence models and streptozotocin(STZ) -induced diabetic mice in vivo and in vitro, and determine the intervention time of adiponectin. By this project we try to provide new targets for delaying vascular aging, and provide a new method for improving diabetic vascular aging.

血管衰老能改变多种心血管疾病发生阈值、进程和严重程度，其与血管平滑肌细胞(VSMCs)过多过快衰老相关。新近研究发现雷帕霉素抑制哺乳动物雷帕霉素靶蛋白(mTOR)可显著促进健康长寿但临床转化受阻。申请人的工作将mTOR与血管衰老联系起来，前期研究首次证明：mTOR信号参与调控VSMCs向成骨细胞转分化和钙化，脂联素减缓这一进程；而血管钙化是血管衰老的重要表型。申请人预实验构建了VSMCs复制性衰老及高糖诱导的早衰模型并发现mTOR表达上调，初步发现脂联素降低高糖诱导的早衰VSMCs的mTOR表达、β-半乳糖酐酶活性及染色阳性率。据此提出假说：mTOR参与调控VSMCs衰老；脂联素通过抑制mTOR信号延缓高糖诱导的VSMCs早衰。我们将用VSMCs两种衰老模型和STZ糖尿病小鼠，通过体内外研究验证假说，并初步确定脂联素干预时点。力图为延缓血管衰老提供新靶点，为改善糖尿病性血管衰老提供新方法。

血管衰老能改变多种心血管疾病发生阈值、进程和严重程度，血管衰老在糖尿病患者中非常常见，是糖尿病患者大血管并发症的常见原因之一，其机制与血管中膜的主要组成细胞血管平滑肌细胞（VSMCs）过多过快衰老相关，抑制VSMCs其衰老有望延缓血管老化。新近研究发现抑制哺乳动物雷帕霉素靶蛋白(mTOR)可促进健康长寿，可能与血管衰老相关但临床转化受阻。本课题在mTOR在血管衰老中的作用进行了一系列研究。. 本项目主要研究内容为以下4点：1.mTOR通路在血管衰老尤其是高血糖导致的血管早衰中的影响及机制，及脂联素在其中的作用；2.高糖对血管的影响目前主要集中在血管内皮细胞（ECs），对VSMCs的钙化/衰老的作用及其机制的报道很少，血循环中的高糖刺激如何越过血管内膜的ECs从而影响血管中膜的VSMCs尚未明确，我们在该方面进行了相关研究；3.研究了相关非编码RNA在糖尿病性血管衰老中的作用及机制；4.临床上，调查了中国社区居住老年人主动脉钙化患病率及与脂联素的关系，以及寻找老年人群血管衰老的生物学标志物。. 本项目研究结果证实：PI3K/Akt/mTOR通路及AMPK/TSC2/mTOR通路调节VSMCs复制性衰老，脂联素可通过抑制mTOR通路延缓高糖诱导的VSMCs早衰，脂联素可能是治疗糖尿病性血管衰老的潜在药物靶点; lncRNA-ES3 / miR-34c-5p / BMF轴参与调节高糖诱导的VSMCs钙化/衰老；高糖环境下血管ECs源性的外泌体携带VCAN蛋白及Notch3蛋白调节VSMCs钙化/衰老；中国社区居住老年人主动脉钙化患病率及与血清脂联素水平呈负相关关系，血清脂联素水平是预测老年人血管钙化的有用的生物学标志物。. 本项目结果明确了血管衰老的部分机制以及为延缓血管衰老提供新思路和新靶点，为探索脂联素等作为预测血管衰老的标志物以及相关药物靶点改善糖尿病性血管衰老的作用及其机制提供新的研究策略。