SIRT6促进组蛋白H3K9去乙酰化延缓血管钙化进程的实验研究

Cardiovascular and cerebrovascular events are the leading cause death for patients with chronic kidney disease. Both our preliminary studies and other reports demonstrated vascular calcification played an important role in this process, and it is the key link in vascular calcification for vascular smooth muscle cells transformating to the osteoblastic phenotype. Recently, it was documented that acetylization of histone H3K9 played an important role in the process vascular smooth muscle cells transformating to the osteoblastic phenotype. We find SIRT6，a member of Sirtuins, has the potential to inhibit vascular calcification, however the detail mechanism is still unclear. Based on our previous and preliminary results, we raise the hypothesis that SIRT6 attenuate the progress of vascular smooth muscle cells transformating to the osteoblastic phenotype by promoting deacetylation of histone H3K9. In this proposal, the in vivo model of vascular calcification model induced by high adenine plus high phosphorus diets, regulated the level of acetylization of histone H3K9 with recombinant SIRT6 adenovirus and SIRT6 siRNA in both animal model and primary vascular smooth muscle cells. Histology, flow cytometry and molecular biology are used to investigate the effect of SIRT6 on vascular calcification. The detail mechanism of SIRT6-histone H3K9-vascular smooth muscle cells phenotype transformation-vascular calcification will be discussed by the in vivo model and primary smooth muscle cells. This project will provide a new therapeutic strategy for vascular calcification.

心脑血管事件是慢性肾脏病患者首位致死原因，国内外报道和我们前期研究均证实血管钙化起重要作用，血管平滑肌细胞向成骨细胞表型转化是血管钙化的核心环节。新近发现组蛋白H3K9乙酰化在调控细胞成骨样转化中扮演关键角色，我们发现SIRT6具有抑制血管钙化的潜能，然而具体机制尚不清楚。结合前期研究和预实验结果，我们提出SIRT6通过促进组蛋白H3K9去乙酰化，抑制成骨转化因子的转录和表达，从而延缓血管平滑肌细胞成骨样转化的假说。本研究拟采用高腺嘌呤高磷饮食诱导小鼠慢性肾脏病血管钙化模型，以SIRT6重组腺病毒和SIRT6 siRNA等调控组蛋白H3K9乙酰化状态，在整体动物模型和原代血管平滑肌细胞两层面，结合组织学，流式细胞技术和分子生物学方法，研究SIRT6对血管钙化的抑制作用，本研究将深入剖析SIRT6－组蛋白H3K9－血管平滑肌细胞表型转化－血管钙化的作用规律，为血管钙化的防治提供新的治疗策略。

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之一。本课题组结合国内外研究进展以及前期预实验结果，提出去长寿蛋白去乙酰化酶SIRT6可能通过表观遗传学修饰调控血管钙化进程的假说。在该研究中，我们发现SIRT6拮抗血管钙的作用机制可能是对成骨表型转化关键转录因子RUNX2进行去乙酰化，使其与核转运因子XPO1结合增加，加速其出核，借此阻断了RUNX2的转录作用。本项目以慢性肾脏病血管钙化模型为基础，深入剖析了SIRT6－RUNX2－血管钙化的作用规律，为血管钙化的防治提供新的治疗策略。