Simulated Microgravity Promotes Angiogenesis through RhoA-Dependent Rearrangement of the Actin Cytoskeleton
Simulated Microgravity Promotes Angiogenesis through RhoA-Dependent Rearrangement of the Actin Cytoskeleton
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DOI：
10.1159/000456060
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发表时间：
2017-01
影响因子：
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通讯作者：
F. Shi;Yong-chun Wang;Zebing Hu;Hongchang Xu;Jing Sun;Yuan Gao;Xiao-tao Li;Chang-bin Yang
中科院分区：
文献类型：
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作者：
F. Shi;Yong-chun Wang;Zebing Hu;Hongchang Xu;Jing Sun;Yuan Gao;Xiao-tao Li;Chang-bin Yang
背景/目的：微重力导致心血管系统的流体动力学改变，并与血管生成增加有关，血管生成是内皮细胞启动新血管生长的一个重要方面。鉴于Rho GTP酶依赖的细胞骨架重排在细胞迁移中的关键作用，小分子GTP酶RhoA可能在微重力诱导的血管生成中发挥潜在作用。方法：在正常重力和模拟微重力条件下，用FITC标记的鬼臼糖苷染色检测人脐静脉内皮细胞(HUVECs)中肌动蛋白微丝的结构，用定量聚合酶链式反应和免疫印迹法检测RhoA的表达和活性。通过细胞迁移和管形成实验分析了模拟微重力对人脐静脉内皮细胞伤口闭合和管形成的影响，以及它们对RhoA的依赖性。结果：我们发现在模拟微重力作用下，人脐静脉内皮细胞肌动蛋白微丝排列紊乱，RhoA活性降低。用C3转移酶Rho抑制剂或siRNA敲除阻断RhoA活性可以模拟模拟微重力诱导HUVECs肌动蛋白细丝解体的效果，随后促进伤口闭合和管状形成，这与微重力处理细胞的效果非常相似。相反，在微重力处理的HUVECs中过表达RhoA恢复了肌动蛋白细丝，并降低了伤口闭合和管道形成能力。结论：RhoA失活参与了模拟微重力条件下血管内皮细胞肌动蛋白重排相关的血管生成反应。
Background/aims: Microgravity leads to hydrodynamic alterations in the cardiovascular system and is associated with increased angiogenesis, an important aspect of endothelial cell behavior to initiate new vessel growth. Given the critical role of Rho GTPase-dependent cytoskeleton rearrangement in cell migration, small GTPase RhoA might play a potential role in microgravity-induced angiogenesis. Methods: We examined the organization of actin filaments by FITC-conjugated phalloidin staining, as well as the expression and activity of RhoA by quantitative PCR and Western blot, in human umbilical vein endothelial cells (HUVECs) under normal gravity and simulated microgravity. Effect of simulated microgravity on the wound closure and tube formation in HUVECs, and their dependence on RhoA, were also analyzed by cell migration and tube formation assays. Results: We show that in HUVECs actin filaments are disorganized and RhoA activity is reduced by simulated microgravity. Blocking RhoA activity either by C3 transferase Rho inhibitor or siRNA knockdown mimicked the effect of simulated microgravity on inducing actin filament disassembly, followed by enhanced wound closure and tube formation in HUVECs, which closely resembled effects seen on microgravity-treated cells. In contrast, overexpressing RhoA in microgravity-treated HUVECs restored the actin filaments, and decreased wound closure and tube formation abilities. Conclusion: These results suggest that RhoA inactivation is involved in the actin rearrangement-associated angiogenic responses in HUVECs during simulated microgravity.