SMN deficiency attenuates migration of U87MG astroglioma cells through the activation of RhoA
SMN deficiency attenuates migration of U87MG astroglioma cells through the activation of RhoA
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DOI：
10.1016/j.mcn.2011.12.003
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发表时间：
2012-03-01
影响因子：
3.5
通讯作者：
Llado, Jeronia
中科院分区：
文献类型：
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作者：
Caraballo-Miralles, Victor;Cardona-Rossinyol, Andrea;Llado, Jeronia
脊髓性肌萎缩症 (SMA) 是一种影响脊髓中 α 运动神经元的神经退行性疾病，由存活运动神经元 1 (SMNI) 基因的纯合缺失或特定突变引起。细胞迁移在神经系统发育的许多阶段都至关重要：为了研究 SMN 在细胞迁移中的作用，用 shSMN 慢载体转导 U87MG 星形胶质瘤细胞，SMN 表达减少了约 60%。在单层伤口愈合测定中，U87MG SMN 耗尽的细胞表现出细胞迁移减少。在这些细胞中，RhoA 被激活，并且肌球蛋白调节轻链 (MLC)（Rho 激酶 (ROCK) 的底物）的磷酸化水平增加。细胞运动性的降低与 RhoA/Rho 激酶 (ROCK) 信号通路的激活有关，因为 ROCK 抑制剂 Y-27632 治疗消除了 SMN 耗尽细胞中的运动缺陷和 MLC 磷酸化。由于细胞迁移是通过肌动蛋白细胞骨架的持续重塑来调节的，因此研究了 SMN 耗尽的细胞中的肌动蛋白分布。观察到肌动蛋白从丝状向单体（球状）转变，涉及应力纤维的消失。此外，profilin I（一种肌动蛋白隔离蛋白）在 SMN 耗尽的细胞中表达增加。已知 SMN 会与 Profilin 发生物理相互作用，从而降低其肌动蛋白隔离活性。目前的结果表明，在 SMN 耗尽的细胞中，profilin I 表达的增加和 SMN 对 profilin 抑制作用的减少可能导致丝状肌动蛋白聚合减少，从而降低细胞运动性。我们认为，本文报道的 SMN 耗尽细胞迁移活动的变化与 RhoA/ROCK 通路的异常激活和 profilin I 表达增加有关，可能通过损害正常神经元和神经胶质细胞迁移，从而在神经系统发育中发挥作用，从而促进 SMA 疾病发病机制。 (C) 2011 Elsevier Inc. 保留所有权利。
Spinal muscular atrophy (SMA) is a neurodegenerative disease that affects alpha motoneurons in the spinal cord caused by homozygous deletion or specific mutations in the survival motoneuron-1 (SMNI) gene. Cell migration is critical at many stages of nervous system development: to investigate the role of SMN in cell migration, U87MG astroglioma cells were transduced with shSMN lentivectors and about 60% reduction in SMN expression was achieved. In a monolayer wound-healing assay, U87MG SMN-depleted cells exhibit reduced cell migration. In these cells, RhoA was activated and phosphorylated levels of myosin regulatory light chain (MLC), a substrate of the Rho kinase (ROCK), were found increased. The decrease in cell motility was related to activation of RhoA/Rho kinase (ROCK) signaling pathway as treatment with the ROCK inhibitor Y-27632 abrogated both the motility defects and MLC phosphorylation in SMN-depleted cells. As cell migration is regulated by continuous remodeling of the actin cytoskeleton, the actin distribution was studied in SMN-depleted cells. A shift from filamentous to monomeric (globular) actin, involving the disappearance of stress fibers, was observed. In addition, profilin I, an actin-sequestering protein showed an increased expression in SMN-depleted cells. SMN is known to physically interact with profilin, reducing its actin-sequestering activity. The present results suggest that in SMN-depleted cells, the increase in profilin I expression and the reduction in SMN inhibitory action on profilin could lead to reduced filamentous actin polymerization, thus decreasing cell motility. We propose that the alterations reported here in migratory activity in SMN-depleted cells, related to abnormal activation of RhoA/ROCK pathway and increased profilin I expression could have a role in developing nervous system by impairing normal neuron and glial cell migration and thus contributing to disease pathogenesis in SMA. (C) 2011 Elsevier Inc. All rights reserved.