Chen Yu-Ying, Hsieh Cheng-Ying, Jayakumar Thanasekaran, Lin Kuan-Hung, Chou Duen-Suey, Lu Wan-Jung, Hsu Ming-Jen, Sheu Joen-Rong
Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Department of Pharmacology, School of Medicine, Taipei Medical University, Taipei, Taiwan.
Sci Rep. 2014 Jul 10;4:5651. doi: 10.1038/srep05651.
The abnormal growth of vascular smooth muscle cells (VSMCs) is considered a critical pathogenic process in inflammatory vascular diseases. We have previously demonstrated that protein phosphatase 2 A (PP2A)-mediated NF-κB dephosphorylation contributes to the anti-inflammatory properties of andrographolide, a novel NF-κB inhibitor. In this study, we investigated whether andrographolide causes apoptosis, and characterized its apoptotic mechanisms in rat VSMCs. Andrographolide activated the p38 mitogen-activated protein kinase (p38MAPK), leading to p53 phosphorylation. Phosphorylated p53 subsequently transactivated the expression of Bax, a pro-apoptotic protein. Transfection with pp2a small interfering RNA (siRNA) suppressed andrographolide-induced p38MAPK activation, p53 phosphorylation, and caspase 3 activation. Andrographolide also activated the Src homology 1 domain-containing protein tyrosine phosphatase (SHP-1), and induced PP2A dephosphorylation, both of which were inhibited by the SHP-1 inhibitor sodium stibogluconate (SSG) or shp-1 siRNA. SSG or shp-1 siRNA prevented andrographolide-induced apoptosis. These results suggest that andrographolide activates the PP2A-p38MAPK-p53-Bax cascade, causing mitochondrial dysfunction and VSMC death through an SHP-1-dependent mechanism.
血管平滑肌细胞（VSMCs）的异常生长被认为是炎症性血管疾病中的一个关键致病过程。我们之前已经证明，蛋白磷酸酶2A（PP2A）介导的NF-κB去磷酸化有助于穿心莲内酯（一种新型NF-κB抑制剂）的抗炎特性。在本研究中，我们调查了穿心莲内酯是否会导致大鼠VSMCs凋亡，并对其凋亡机制进行了表征。穿心莲内酯激活了p38丝裂原活化蛋白激酶（p38MAPK），导致p53磷酸化。磷酸化的p53随后反式激活促凋亡蛋白Bax的表达。用pp2a小干扰RNA（siRNA）转染可抑制穿心莲内酯诱导的p38MAPK激活、p53磷酸化和半胱天冬酶3激活。穿心莲内酯还激活了含Src同源1结构域的蛋白酪氨酸磷酸酶（SHP-1），并诱导PP2A去磷酸化，这两者均被SHP-1抑制剂葡糖酸锑钠（SSG）或shp-1 siRNA抑制。SSG或shp-1 siRNA可预防穿心莲内酯诱导的凋亡。这些结果表明，穿心莲内酯通过SHP-1依赖性机制激活PP2A-p38MAPK-p53-Bax级联反应，导致线粒体功能障碍和VSMC死亡。
