上调血管平滑肌细胞线粒体ANT1改善慢性肾脏病周向张应力过负荷所致血管钙化的研究

The leading cause of death in patients with chronic kidney disease (CKD) is cardiovascular events, in which vascular calcification plays an important role. Recently, we discover an important association between vascular calcification and hypertension. Cyclic strain overload induced by hypertension triggers the osteoblastic transdifferentiation of vascular smooth muscle cells (VSMC) by activating transient receptor potential melastatin 7 (TRPM7) channel. In this process, the level of adenine nucleotide translocator 1 (ANT1), a critical regulator of mitochondrial energy metabolism, is dramatically decreased, however, the underlying mechanisms are not understood. Based on the preliminary results, we raise the hypothesis that upregulating mitochondrial ANT1 of VSMC may attenuate vascular calcification induced by cyclic strain overload in CKD. In this proposal, we will prove the definite relationship between aortic calcification and hemodynamics in CKD patients by combination of CT and MR scanning techniques. Then we will build up an in vivo CKD animal model with cyclic strain overload as well as in vitro primary VSMC model treated with high phosphate under cyclic strain overload by the Flexcell system. The detailed mechanism of cyclic strain overload-ANT1-vascular calcification will be deeply investigated by a series of experimental techniques such as micro-CT and patch clamp. This project will evaluate whether upregulation of ANT1 expression can serve as a novel therapeutic strategy for vascular calcification in CKD.

慢性肾脏病（CKD）患者首位死因是心血管事件，血管钙化在其中扮演关键角色，我们发现CKD血管钙化与高血压密切相关，血管周向张应力过负荷可通过TRPM7诱发血管平滑肌细胞成骨样转分化，其中线粒体ANT1水平显著下降，但机理未明。结合前期基础，我们提出通过上调线粒体ANT1可抑制周向张应力过负荷所致CKD血管钙化的假说。本研究通过CT和MR融合技术建立主动脉钙化与血流动力学分析模型，揭示CKD患者主动脉钙化与血管周向张应力的关系。进一步在小鼠周向张应力过负荷CKD模型及和体外Flexcell细胞周向张应力加载系统，结合小动物CT、膜片钳等实验手段，探究上调ANT1对血管钙化的逆转作用。本研究将深入剖析CKD中周向张应力过负荷-TRPM7-ANT1-血管钙化的作用规律，为血管钙化防治新策略提供依据。

血管钙化是引发慢性肾脏病患者心血管事件高发生率和全因死亡率的主要原因。本课题组结合国内外研究进展以及前期预实验结果，提出周向应力过载引起的线粒体损伤促进血管钙化进程的假说。在该研究中，我们发现钙化进程中的线粒体损伤的关键机制是线粒体中SIRT3表达减少而导致线粒体外膜蛋白泛素化水平降低，进一步使线粒体自噬受损。线粒体损伤后的胞质线粒体DNA增多及活性氧自由基过载，激活了下游多个炎症信号通路从而加速的血管钙化。在该过程中膜蛋白TRPM7和线粒体蛋白ANT1扮演重要角色。本项目以慢性肾脏病血管钙化模型和临床样本为基础，深入剖析了周向应力过载和线粒体损伤在血管钙化中的作用规律，为血管钙化的防治提供新的治疗策略。