转录因子SP1调控血管平滑肌细胞表型转化在主动脉夹层发病中的作用

The effects of transcription factor SP1 on phenotypic switching of vascular smooth muscle cells in pathogenesis of aortic dissection

目的:探讨转录因子SP1在主动脉夹层组织中的表达情况及与主动脉夹层血管平滑肌细胞(VSMC)表型转化的关系。方法:收集人主动脉夹层血管壁组织(n=10)及正常主动脉壁组织(n=4),分别采用RT-PCR和Western blot检测主动脉壁组织中SP1和收缩型VSMC表型标志物SM22α的mRNA和蛋白表达水平;体外培养正常人主动脉平滑肌细胞(HA-VSMC),以转染SP1过表达腺病毒(Ad-SP1)的HA-VSMC为Ad-SP1组,以转染仅表达荧光蛋白腺病毒(Ad-GFP)的HA-VSMC为对照组,分别采用RT-PCR和Western blot检测转染后HA-VSMC中SM22αmRNA和蛋白表达水平。结果:与正常主动脉壁组织相比,人主动脉夹层血管壁组织中SP1 mRNA(3.81±2.84对0.91±0.67,P<0.05)和蛋白(2.09±0.32对0.90±0.09,P<0.05)表达水平均明显升高,SM22αmRNA(0.39±0.20对1.01±0.51,P<0.05)和蛋白(0.75±0.10对1.01±0.09,P<0.05)表达水平均明显下降;腺病毒转染HA-VSMC后,与对照组相比,Ad-SP1组中SM22αmRNA(0.36±0.03对0.95±0.11,P<0.05)和蛋白(0.84±0.11对1.06±0.06,P<0.05)表达水平均明显下降。结论:转录因子SP1在主动脉夹层组织中表达水平升高,与VSMC表型转化密切相关,参与主动脉夹层的发病过程。

Objective：To investigate the expression level of specificity protein1（SP1）in the tissue from human aortic dissection（AD）and the relationship between SP1 and phenotypic switching of vascular smooth muscle cell（VSMC）in aorta. Methods：Human aortic wall tissues were collected from ten AD patients and four normal donors.The mRNA and protein expressions of SP1 and contractile VSMC marker SM22αwere detected by RT-PCR and western blot.Normal human aorta smooth muscle cells（HA-VSMC）were cultured in vitro.Human SP1 overexpression adenovirus（Ad-SP1）was constructed and used to transfect HA-VSMC,using GFP expression adenovirus（Ad-GFP）as control.The expressions of SM22αin HA-VSMC after transfection were detected by RT-PCR and western blot. Results：Compared with normal aortic wall tissues,the expressions of SP1 in AD tissues were significantly upregulated in both mRNA level（3.81±2.84 vs.0.91±0.67,P〈0.05）and protein level（2.09±0.32 vs.0.90±0.09,P〈0.05）,while the SM22αexpressions were downregulated（mRNA0.39±0.20 vs.1.01±0.51,P〈0.05;protein0.75±0.10 vs.1.01±0.09,P〈0.05）.Compared with control group,the expressions of SM22α in HA-VSMC cultured in vitro were significantly downregulated after successful overexpression of SP1 by Ad-SP1（mRNA0.36±0.03 vs.0.95±0.11,P〈0.05;protein 0.84±0.11 vs.1.06±0.06,P 〈0.05）. Conclusion：In AD tissue,SP1 is upregulated and closely correlated with VSMC phenotypic switching,indicating that SP1 may participate in the pathogenesis of AD.