血管平滑肌细胞（VSMC）表型转化（收缩型变为增殖型）是导致心血管疾病中血管狭窄的主要原因。近期我们发现多功能Tudor-SN蛋白在VSMC中的表达与细胞增殖能力相关,并促进VSMC的周期进程及增殖。本课题拟从动物、细胞和分子水平探讨Tudor-SN调控VSMC表型转化的机制：1)通过干扰Smad3或Sp1的表达，同时给予PDGF刺激，分析VSMC表型转化时Tudor-SN表达上升的调控机制；2) 利用Tudor-SN基因敲除小鼠及野生型小鼠建立动脉损伤模型，探讨Tudor-SN对损伤下VSMC表型转化的影响；3)利用PDGF诱导VSMC增殖，研究Tudor-SN对VSMC收缩能力和迁移能力的影响；4) 通过对筛选的靶基因进行PCR和WB的验证，明确Tudor-SN蛋白发挥作用的信号转导通路；5)荧光素酶实验、组蛋白ChIP及CoIP实验将揭示Tudor-SN调控靶基因转录的方式。

Phenotypic switching of vascular smooth muscle cell (VSMC) is considered as a leading cause for hemadostenosis in the cardiovascular disease. Very recently, we found that the expression level of multifunctional Tudor-SN protein in VSMC was associated with the proliferation ability of VSMC, and Tudor-SN could promote cell cycle progress and enhance proliferation ability of VSMC. The present project was designed to investigate the regulation mechanism of Tudor-SN in the VSMC phenotype transformation in terms of animal, cellular and molecular levels. 1) The expression levels of Smad3 or Sp1 were interfered to analyze the molecular mechanism of unregulated Tudor-SN during VSMC phenotype transformation.2) Tudor-SN-KO and Tudor-SN-WT C57BL/6N mices were utilized to study whether Tudor-SN has any effects on VSMC phenotypic switching after carotid artery injury in vivo. 3) PDGF was also used to induce the proliferation of VSMC, in order to evaluate the effect of Tudor-SN on the retraction, migration ability of VSMC. 4) To confirm the Tudor-SN-associated signal transduction pathway in the VSMC phenotype transformation, the PCR and western blotting assays were performed to validate the targeting genes. 5) ChIP assay of histone and CoIP were also performed to study the regulation mechanism of Tudor-SN in gene transcription.