Intracellular signal transduction for migration and actin remodeling in vascular smooth muscle cells after sphingosylphosphorylcholine stimulation
Intracellular signal transduction for migration and actin remodeling in vascular smooth muscle cells after sphingosylphosphorylcholine stimulation
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DOI：
10.1152/ajpheart.00901.2005
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Kohama, Kazuhiro
中科院分区：
文献类型：
--
作者：
Li, Sheng;Tanaka, Hideyuki;Kohama, Kazuhiro
血管平滑肌细胞（VSMCs）向鞘氨醇磷酸胆碱（SPC）迁移的分子机制进行了分析，在光的假设，肌动蛋白细胞骨架的重塑应参与。在SPC刺激后，发现有丝分裂原活化蛋白激酶（MAPK），包括p38 MAPK（p38）和p42/44 MAPK（p42/44）被磷酸化。在存在SB-203580（一种p38抑制剂）的情况下，细胞向SPC的迁移减少，但不存在PD-98059（一种p42/44抑制剂）。G（i）蛋白抑制剂百日咳毒素（PTX）可抑制p38磷酸化和VSMC迁移。SPC刺激后，无论是否用SB-203580或PTX预处理，均发生肌球蛋白轻链（MLC）磷酸化。MLC激酶抑制剂ML-7和Rho激酶抑制剂Y-27632抑制MLC磷酸化，但仅部分抑制SPC定向迁移。加入SB-203580可实现完全抑制。SPC刺激后，肌动蛋白细胞骨架在细胞周围形成粗的肌动蛋白丝束，细胞被细长的丝状伪足包围，即，magunapodia。周围的肌动蛋白束由α-和β-肌动蛋白，但magunapodia完全由β-肌动蛋白。加入SB-203580和PTX可以逆转肌动蛋白的这种重塑，但ML-7或Y-27632不能逆转。两者合计，我们的生化和形态学数据证实了肌动蛋白重塑的调节，并表明VSMCs向SPC迁移，不仅通过MLC磷酸化依赖的途径，而且通过MLC磷酸化独立的途径。
Molecular mechanisms underlying migration of vascular smooth muscle cells (VSMCs) toward sphingosylphosphorylcholine (SPC) were analyzed in light of the hypothesis that remodeling of the actin cytoskeleton should be involved. After SPC stimulation, mitogen-activated protein kinases (MAPKs), including p38 MAPK (p38) and p42/44 MAPK (p42/44), were found to be phosphorylated. Migration of cells toward SPC was reduced in the presence of SB-203580, an inhibitor of p38, but not PD-98059, an inhibitor of p42/44. Pertussis toxin (PTX), a G(i) protein inhibitor, induced an inhibitory effect on p38 phosphorylation and VSMC migration. Myosin light chain (MLC) phosphorylation occurred after SPC stimulation with or without pretreatment with SB-203580 or PTX. The MLC kinase inhibitor ML-7 and the Rho kinase inhibitor Y-27632 inhibited MLC phosphorylation but only partially inhibited SPC-directed migration. Complete inhibition was achieved with the addition of SB-203580. After SPC stimulation, the actin cytoskeleton formed thick bundles of actin filaments around the periphery of cells, and the cells were surrounded by elongated filopodia, i.e., magunapodia. The peripheral actin bundles consisted of alpha- and beta-actin, but magunapodia consisted exclusively of beta-actin. Such a remodeling of actin was reversed by addition of SB-203580 and PTX, but not ML-7 or Y-27632. Taken together, our biochemical and morphological data confirmed the regulation of actin remodeling and suggest that VSMCs migrate toward SPC, not only by an MLC phosphorylation-dependent pathway, but also by an MLC phosphorylation-independent pathway.