Liu Yu, Xu Ding-Li, Wang Ming-Hui, Ouyang Ping, Lai Wen-Yan
Department of Cardiology, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China.
Di Yi Jun Yi Da Xue Xue Bao. 2002 Feb;22(2):114-6.
To investigate the role of mitogen-activated protein kinase (MAPK) in the regulation of cyclin-dependent kinase inhibitors (CDKI) in the process of vascular smooth muscle cell (VSMC) hypertrophy induced by angiotensin II stimulation.
The medial layer of male SD rat aorta was isolated for VSMC culture. After cultured in serum-free medium to arrest the cell growth, VSMCs were stimulated with angiotensin II (1x10(-6) mol/L) or/and phorbol myristate acetate (PMA, 20 nmol/L), with the cells cultured in serum-free medium serving as control. MAPK activity of the cells was assayed 90 min after stimulation with immunoprecipitation test, and the expression levels of CDKI p27, p57 and p21 were determined by Western blotting 6 and 24 h after stimulation respectively.
Compared with the control level, MAPK activity of the VSMCs was up-regulated by 238% by treatment with angiotensin II alone which, however, did not inhibit p27 expression or induce VSMC proliferation. Costimulation with angiotensin II and PMA slightly inhibited p27 expression but VSMC proliferation was still not observed.
MAPK pathway is an important channel for extracellular proliferative and hypertrophic signal transduction into the nucleus of VSMCs.
探讨丝裂原活化蛋白激酶（MAPK）在血管紧张素II刺激诱导血管平滑肌细胞（VSMC）肥大过程中对细胞周期蛋白依赖性激酶抑制剂（CDKI）调节的作用。
分离雄性SD大鼠主动脉中层进行VSMC培养。在无血清培养基中培养以阻止细胞生长后，用血管紧张素II（1×10⁻⁶mol/L）或/和佛波酯（PMA，20nmol/L）刺激VSMC，以在无血清培养基中培养的细胞作为对照。刺激90分钟后用免疫沉淀试验检测细胞的MAPK活性，刺激6小时和24小时后分别用蛋白质印迹法测定CDKI p27、p57和p21的表达水平。
与对照水平相比，单独用血管紧张素II处理使VSMC的MAPK活性上调238%，但这并未抑制p27表达或诱导VSMC增殖。血管紧张素II和PMA共同刺激轻微抑制p27表达，但仍未观察到VSMC增殖。
MAPK途径是细胞外增殖和肥大信号转导至VSMC细胞核的重要通道。
