PARP1介导的Runx2多聚ADP核糖化反应在血管平滑肌成骨样表型转化及肾衰血管钙化中作用和机制研究

Vascular calcification is highly prevalent in end-stage renal diseases and is predictive of cardiovascular events and mortality. PARP1-mediated poly(ADP-ribosyl)ation, an important post-transcriptional modification of proteins, is the major response manner for cellular stimulus and has been implicated in maintaining the normal cellular physiological processes. Here we show that PARP activity is increased in renal artery samples from patients with chronic renal failure. PARP1 deficiency blocks the calcium deposition, and expression of mineralization-regulating genes, especially Runx2, a key transcriptional factor involved in vascular calcification. Mass spectrometry data showed that PARP1 may directly interact with Runx2. Together, these preliminary results suggested that PARP1 deficiency may counteracts vascular calcification and mediate osteogenic gene expressions via regulating Runx2. In this project, we will continue to further explore the role and mechanism of PARP1-mediated poly(ADP-ribosyl)ation in the osteogenic phenotypic switch of vascular smooth muscle cells and vascular calcification, and provide a new insight on the prevention and treatment of a variety of cardiovascular diseases related to vascular calcification.

血管钙化与终末期肾脏病高度相关，是心血管事件发生及死亡的关键预测因素。PARP1介导的多聚ADP核糖化反应是一种重要的转录后修饰方式，它是细胞对刺激反应下的主要反应模式，同时对维持细胞正常的生理过程中起到重要作用。申请人首次发现在与供肾患者的肾动脉相比，受肾患者的肾动脉组织内PARP1表达及多聚ADP核糖化明显增加；敲除PARP1后，血管钙盐沉积显著下降，钙化表型相关基因，特别是血管钙化关键转录因子Runx2表达也明显下调；免疫共沉淀后质谱结果分析显示PARP1可能与Runx2相互作用。提示PARP1缺失能够抵抗血管钙化，通过Runx2进而调节骨化相关基因表达。因此，本项目将继续深入阐明PARP1介导的Runx2多聚ADP核糖化反应在血管平滑肌成骨/软骨样表型转换及血管钙化的作用及机制，将为治疗及预防心血管疾病相关血管钙化提供新的思路及视野。

血管钙化与终末期肾脏病高度相关，是心血管事件发生及死亡的关键预测因素。PARP1介导的多聚ADP核糖化反应是一种重要的转录后修饰方式，它是细胞对刺激反应下的主要反应模式，同时对维持细胞正常的生理过程中起到重要作用。本项目采用血管平滑肌细胞，血管组织及动物血管钙化模型，研究了PARP1调控血管钙化的作用及机制。我们研究结果显示：PARP1是慢性肾衰血管钙化进展中关键因子，PARP1在血管平滑肌细胞，血管环钙化及慢性肾脏病大鼠血管钙化过程中表达水平上调。过表达PARP1可促进血管平滑肌细胞钙化；而敲低PARP1能明显减轻血管平滑肌细胞钙化。动物实验也证明过表达PARP1能加速慢性肾脏病大鼠主动脉钙化，而敲低PARP1能缓解慢性肾脏病大鼠主动脉钙化。我们结果发现其作用机制通过调节血管平滑肌细胞Runx2的表达，抑制Runx2的转录后修饰，进而减少Runx2诱导的血管平滑肌细胞成骨样转化，改善慢性肾衰血管功能。据此，我们得出结论PARP1是慢性肾衰所致血管钙化的关键蛋白，通过上调Runx2促进血管钙化。本项目所得结果将为临床治疗进步提供新的靶点和理论实验依据。