Panx3调控血管钙化的作用及分子机制

Vascular calcification is a major risk factor for cardiovascular morbidity and mortality. Currently, it is known that vascular calcification is an actively gene-regulated biological process resembling bone formation, but the underlying mechanisms remain unclear. Panx3, which is mainly expressed in bone and cartilage, promotes osteoblast differentiation through activation of PI3K/AKT signal. Our preliminary data show that Panx3 expression was increased in vascular smooth muscle cells during the process of vascular calcification. Moreover, inhibition of Panx3 reduced the expression of Runx2，the key factor of vascular calcification. Panx3 overexpression acivated PI3K/AKT signal and promoted calcification of vascular smooth muscle cells. Therefore, we hypothesize that Panx3 may promote osteogenic differentiation of vascular smooth muscle cells and vascular calcification via activation of PI3K/AKT/Runx2 signaling pathway. In this study, we will establish in vitro and in vivo model of vascular calcification, and collect clinical samples. Adenovirus over-expressing Panx3, short interfering RNA against Panx3 and luciferase reporter assay will be used to investigate the critical role of Panx3 in the progression of vascular calcification. Additionally, we will determine whether Panx3 modulates vascular calcification through activation of PI3K/AKT/Runx2 signaling pathway, thus providing a novel potential target for the prevention and treatment of vascular calcification.

血管钙化是心血管疾病发生率和死亡率增加的主要危险因素。目前已知血管钙化是类似骨生成的主动生物调节过程，然而其分子调控机制尚不清楚。Panx3主要表达在骨和软骨组织，可通过激活PI3K/AKT信号促进成骨细胞分化。在前期实验中，我们发现Panx3在血管钙化过程中表达增加，抑制Panx3能下调血管钙化关键因子Runx2的表达，过表达Panx3能明显激活PI3K/AKT信号分子和促进血管平滑肌细胞钙化。因此，我们假定：Panx3可通过激活PI3K/AKT/Runx2信号通路，促进血管平滑肌细胞成骨分化，从而导致血管钙化的发生。本项目将在前期的研究基础上，采用体内和体外血管钙化模型及临床样本，应用腺病毒，RNA干扰和荧光素酶报告基因分析等技术，深入探讨Panx3在血管钙化过程中的关键作用，明确Panx3调节血管钙化的PI3K/AKT/Runx2信号机制，为血管钙化的防治提供新的潜在干预靶点。

血管钙化是与骨形成十分类似的主动生物学调节过程。Panx3在成骨细胞和软骨细胞出现较特异性的表达，能促进成骨细胞和软骨细胞的分化，但Panx3是否调节血管钙化尚不清楚。本项目采用血管平滑肌细胞和慢性肾脏病大鼠血管钙化模型，详细地研究了Panx3对血管钙化的调控作用及分子机制。我们首先研究了血管钙化过程中Panx3的表达水平变化。结果显示：在大鼠血管平滑肌细胞及慢性肾脏病大鼠血管钙化过程中Panx3的表达上调，人体钙化血管Panx3的表达水平明显升高。其次，我们研究了Panx3调节血管平滑肌细胞钙化的作用。过表达Panx3可促进大鼠血管平滑肌细胞成骨样分化和钙化，而敲低Panx3可抑制血管平滑肌细胞成骨样分化和钙化。血管环钙化实验结果显示：过表达Panx3能促进大鼠和人体血管环钙化。动物实验结果显示：过表达Panx3能促进慢性肾脏病大鼠主动脉钙化，而敲低Panx3能抑制慢性肾脏病大鼠主动脉钙化。最后，我们阐明了Panx3促进血管钙化的分子机制。结果显示：Panx3可正向调控血管平滑肌细胞嘌呤受体P2Y6的表达，抑制嘌呤受体P2Y6可减轻Panx3诱导的血管平滑肌细胞钙化，提示P2Y6介导了Panx3诱导的血管钙化。综上，本研究证明了Panx3可通过上调嘌呤受体P2Y6，促进血管平滑肌细胞成骨样分化，从而导致血管钙化的发生。本项研究结果可为血管钙化的防治提供新的思路。