Zhang Ming, Yang Min, Liu Li-ping, Lau Wayne Bond, Gao Hai, Xin Man-kun, Su Li-Xiao, Wang Jian, Cheng Shu-Juan, Fan Qian, Liu Jing-Hua
Department of Cardiology, Beijing An Zhen Hospital, Capital Medical University, and Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing 100029, China.
Department of Cardiology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China.
Oxid Med Cell Longev. 2014;2014:294150. doi: 10.1155/2014/294150. Epub 2014 Mar 20.
The disruption of physiologic vascular smooth muscle cell (VSMC) migration initiates atherosclerosis development. The biochemical mechanisms leading to dysfunctional VSMC motility remain unknown. Recently, cytokine BMP-2 has been implicated in various vascular physiologic and pathologic processes. However, whether BMP-2 has any effect upon VSMC motility, or by what manner, has never been investigated.
VSMCs were adenovirally transfected to genetically overexpress BMP-2. VSMC motility was detected by modified Boyden chamber assay, confocal time-lapse video assay, and a colony wounding assay. Gene chip array and RT-PCR were employed to identify genes potentially regulated by BMP-2. Western blot and real-time PCR detected the expression of myosin Va and the phosphorylation of extracellular signal-regulated kinases 1/2 (Erk1/2). Immunofluorescence analysis revealed myosin Va expression locale. Intracellular Ca(2+) oscillations were recorded.
VSMC migration was augmented in VSMCs overexpressing BMP-2 in a dose-dependent manner. siRNA-mediated knockdown of myosin Va inhibited VSMC motility. Both myosin Va mRNA and protein expression significantly increased after BMP-2 administration and were inhibited by Erk1/2 inhibitor U0126. BMP-2 induced Ca(2+) oscillations, generated largely by a "cytosolic oscillator".
BMP-2 significantly increased VSMCs migration and myosin Va expression, via the Erk signaling pathway and intracellular Ca(2+) oscillations. We provide additional insight into the pathophysiology of atherosclerosis, and inhibition of BMP-2-induced myosin Va expression may represent a potential therapeutic strategy.
生理性血管平滑肌细胞（VSMC）迁移的破坏引发动脉粥样硬化的发展。导致VSMC运动功能失调的生化机制尚不清楚。最近，细胞因子骨形态发生蛋白-2（BMP-2）已被证明参与各种血管生理和病理过程。然而，BMP-2是否对VSMC运动有任何影响，以及通过何种方式产生影响，从未被研究过。
通过腺病毒转染使VSMC基因过表达BMP-2。采用改良的Boyden小室试验、共聚焦延时视频试验和集落损伤试验检测VSMC的运动能力。利用基因芯片阵列和逆转录-聚合酶链反应（RT-PCR）鉴定可能受BMP-2调控的基因。蛋白质免疫印迹法和实时PCR检测肌球蛋白Va的表达以及细胞外信号调节激酶1/2（Erk1/2）的磷酸化。免疫荧光分析揭示肌球蛋白Va的表达位置。记录细胞内Ca(2+)振荡。
过表达BMP-2的VSMC中，VSMC迁移呈剂量依赖性增加。小干扰RNA（siRNA）介导的肌球蛋白Va敲低抑制了VSMC的运动能力。给予BMP-2后，肌球蛋白Va的mRNA和蛋白表达均显著增加，并被Erk1/2抑制剂U0126抑制。BMP-2诱导Ca(2+)振荡，主要由“胞质振荡器”产生。
BMP-2通过Erk信号通路和细胞内Ca(2+)振荡显著增加VSMC迁移和肌球蛋白Va表达。我们为动脉粥样硬化的病理生理学提供了新的见解，抑制BMP-2诱导的肌球蛋白Va表达可能代表一种潜在的治疗策略。
