Blokhin National Medical Research Center of Oncology, Ministry of Health of the Russian Federation, Moscow, 115478, Russia.
Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
Biochemistry (Mosc). 2024 Jan;89(1):184-195. doi: 10.1134/S0006297924010127.
Cell migration is largely determined by the type of protrusions formed by the cell. Mesenchymal migration is accomplished by formation of lamellipodia and/or filopodia, while amoeboid migration is based on bleb formation. Changing of migrational conditions can lead to alteration in the character of cell movement. For example, inhibition of the Arp2/3-dependent actin polymerization by the CK-666 inhibitor leads to transition from mesenchymal to amoeboid motility mode. Ability of the cells to switch from one type of motility to another is called migratory plasticity. Cellular mechanisms regulating migratory plasticity are poorly understood. One of the factors determining the possibility of migratory plasticity may be the presence and/or organization of vimentin intermediate filaments (VIFs). To investigate whether organization of the VIF network affects the ability of fibroblasts to form membrane blebs, we used rat embryo fibroblasts REF52 with normal VIF organization, fibroblasts with vimentin knockout (REF), and fibroblasts with mutation inhibiting assembly of the full-length VIFs (REF117). Blebs formation was induced by treatment of cells with CK-666. Vimentin knockout did not lead to statistically significant increase in the number of cells with blebs. The fibroblasts with short fragments of vimentin demonstrate the significant increase in number of cells forming blebs both spontaneously and in the presence of CK-666. Disruption of the VIF organization did not lead to the significant changes in the microtubules network or the level of myosin light chain phosphorylation, but caused significant reduction in the focal contact system. The most pronounced and statistically significant decrease in both size and number of focal adhesions were observed in the REF117 cells. We believe that regulation of the membrane blebbing by VIFs is mediated by their effect on the focal adhesion system. Analysis of migration of fibroblasts with different organization of VIFs in a three-dimensional collagen gel showed that organization of VIFs determines the type of cell protrusions, which, in turn, determines the character of cell movement. A novel role of VIFs as a regulator of membrane blebbing, essential for manifestation of the migratory plasticity, is shown.
细胞迁移在很大程度上取决于细胞形成的突起类型。间质迁移是通过形成片状伪足和/或丝状伪足来完成的,而阿米巴样迁移则基于泡状突起的形成。迁移条件的改变会导致细胞运动特征的改变。例如,CK-666 抑制剂抑制 Arp2/3 依赖性肌动蛋白聚合会导致细胞从间质样运动模式转变为阿米巴样运动模式。细胞从一种运动模式转变为另一种运动模式的能力称为迁移可塑性。细胞调节迁移可塑性的机制尚未完全了解。决定迁移可塑性可能性的因素之一可能是波形蛋白中间丝(VIFs)的存在和/或组织。为了研究 VIF 网络的组织是否会影响成纤维细胞形成质膜泡的能力,我们使用了具有正常 VIF 组织的大鼠胚胎成纤维细胞 REF52、波形蛋白敲除(REF)的成纤维细胞和突变抑制全长 VIF 组装的成纤维细胞(REF117)。用 CK-666 处理细胞诱导泡状突起的形成。波形蛋白敲除并没有导致泡状突起形成的细胞数量显著增加。短片段波形蛋白的成纤维细胞自发形成泡状突起的细胞数量以及在 CK-666 存在下形成泡状突起的细胞数量都显著增加。VIF 组织的破坏并没有导致微管网络或肌球蛋白轻链磷酸化水平的显著变化,但导致了焦点接触系统的显著减少。在 REF117 细胞中,焦点附着系统的大小和数量都明显减少,并且具有统计学意义。我们认为,VIF 对质膜泡形成的调节是通过它们对焦点附着系统的影响来介导的。分析不同 VIF 组织的成纤维细胞在三维胶原凝胶中的迁移,结果表明,VIF 的组织决定了细胞突起的类型,而细胞突起的类型又决定了细胞运动的特征。研究表明,VIF 作为膜泡形成的调节剂具有新的作用,这对于表现出迁移可塑性是必不可少的。