摘要
目的探讨血管紧张素Ⅱ-1型受体(angiotensinⅡtype 1 receptor,AT1R)自身抗体(AT1R autoantibody,AT1-AA)通过促进血管平滑肌细胞(vascular smooth muscle cells,VSMCs)生物钟蛋白BMAL1异常表达诱导细胞表型转换以及血管纤维化的作用机制。方法将12只6~8周的SD雄性大鼠(体质量180~220 g)按随机数字表法分为2组(n=6):对照组以及使用AT1R细胞外第二环(extracellular loopⅡof angiotensinⅡtype 1 receptor,AT1R-ECLⅡ)主动免疫SD大鼠建立的AT1-AA阳性组。采用HE染色和Masson染色分别观察2组大鼠胸主动脉血管结构变化和纤维化情况(n=3)。采用Western blot检测血管组织以及原代VSMCs中纤维化标志蛋白CollagenⅠ、表型转换相关蛋白SM22、α-SMA、OPN以及MMP2的表达(n=4),此外,还检测了CT0、CT4、CT8、CT12、CT16、CT20时生物钟蛋白BMAL1的表达。通过Transwell实验和划痕实验检测VSMCs的增殖迁移能力(n=3),使用si-RNA技术敲低Bmal1后检测BMAL1、CollagenⅠ、表型转换相关蛋白的表达(n=3)。另外,构建AT1-AA阳性的AT1R敲除(AT1R-KO)大鼠模型使用Western blot检测其胸主动脉血管组织BMAL1的表达(n=4)。结果AT1-AA阳性大鼠胸主动脉血管壁增厚[(140±9)%vs(120±5)%,P<0.05],血管平滑肌细胞排列紊乱,Masson染色蓝染明显,且CollagenⅠ表达较Control组表达上调(P<0.05)。AT1-AA阳性大鼠胸主动脉以及AT1-AA处理的VSMCs中收缩表型相关蛋白α-SMA、SM22表达下降(P<0.05),合成表型相关蛋白OPN、MMP2表达上调(P<0.05);AT1-AA诱导VSMCs划痕愈合能力以及迁移能力都显著增强。进一步发现,Bmal1的mRNA表达(0.67±0.26 vs 1.03±0.17)以及蛋白表达(0.46±0.06 vs 0.85±0.26)均在CT12时显著上调(P<0.05),且Bmal1的节律性消失(P<0.05)。敲低BMAL1后,AT1-AA诱导的VSMCs表型转换现象得到部分改善。与AT1-AA阳性的WT大鼠比较,AT1-AA阳性的AT1R-KO大鼠胸主动脉血管中BMAL1表达明显降低(1.35±0.06 vs 0.86±0.07,P<0.001);细胞水平发现AT1-AA诱导的VSMCs表型转换及胶原蛋白CollagenⅠ高表达的现象在AT1R-KO的VSMCs中得到部分改善。结论AT1-AA通过AT1R-Bmal1轴促进VSMCs表型转换以及血管纤维化。
Objective To investigate the mechanism by which angiotensinⅡtype 1 receptor autoantibody(AT1-AA)promotes phenotypic switch of vascular smooth muscle cells(VSMCs)and vascular fibrosis through abnormal expression of circadian clock protein BMAL1.Methods Twelve male SD rats(6~8 weeks old,weighing 180~220 g)were randomly divided into(n=6)a control group and an AT1-AA-positive group[established by active immunization of SD rats with AT1R extracellular loopⅡpeptide(AT1R-ECLⅡ)].HE and Masson stainings were used to observe structural changes and fibrosis in the thoracic aorta(n=3).Western blotting was performed to detect the expression of Collagen I,phenotypic switch-related proteins(SM22,α-SMA,OPN and MMP2)in vascular tissues and primary VSMCs(n=4),as well as the expression of BMAL1 at CT0,CT4,CT8,CT12,CT16,and CT20.Transwell and scratch assays were used to assess the proliferation and migration of VSMCs(n=3).si-RNA was employed to knock down Bmal1,followed by detection of BMAL1,Collagen I,and phenotypic conversion-related protein expression(n=3).Additionally,AT1-AA-positive AT1R-knockout(AT1R-KO)rats were constructed to measure BMAL1 expression in thoracic aortic tissues(n=4).Results The AT1-AA-positive rats had significantly thickened thoracic aortic vessel wall[(140±9)%vs(120±5)%,P<0.05],badly arranged VSMCs,obvious blue Masson staining,and up-regulated Collagen I expression(P<0.05).In the thoracic aorta of AT1-AA-positive rats and AT1-AA-treated VSMCs,the expression of contractile phenotype-related proteins(α-SMA,SM22)was decreased(P<0.05),while the expression of synthetic phenotype-related proteins(OPN,MMP2)was increased(P<0.05).AT1-AA enhanced the scratch healing ability and migration ability of VSMCs.Furthermore,both mRNA and protein levels of Bmal1 were significantly up-regulated at CT12(P<0.05),and the rhythmicity of Bmal1 was lost.Knockdown of Bmal1 partially ameliorated AT1-AA-induced phenotypic switch of VSMCs.Compared with AT1-AA-positive WT rats,AT1-AA-positive AT1R-KO rats showed significantly reduced BMAL1 expression in the thoracic aorta(1.35±0.06 vs 0.86±0.07,P<0.001).At the cellular level,AT1-AA-induced phenotypic switch and high Collagen I expression in VSMCs were partially improved in AT1R-KO VSMCs.Conclusion AT1-AA promotes VSMCs phenotypic conversion and vascular fibrosis through the AT1R-Bmal1 axis.
作者
薛灵霞
龙瑶琳
冯佳艳
毛田
郭娇
王卓玺
李杨
王晓晖
王丽
XUE Lingxia;LONG Yaolin;FENG Jiayan;MAO Tian;GUO Jiao;WANG Zhuoxi;LI Yang;WANG Xiaohui;WANG Li(School of Basic Medical Sciences,Shanxi Medical University,Taiyuan,Shanxi,China)
出处
《陆军军医大学学报》
北大核心
2025年第11期1155-1164,共10页
Journal of Army Medical University
基金
国家自然科学基金面上项目(31871177)
山西省基础研究规划青年科学研究项目(202203021212360)
山西省高等学校科技创新项目(2022L115)。
