Lepannetier Sophie, Zanou Nadège, Yerna Xavier, Emeriau Noémie, Dufour Inès, Masquelier Julien, Muccioli Giulio, Tajeddine Nicolas, Gailly Philippe
Université catholique de Louvain, Institute of Neuroscience, Laboratory of Cell Physiology, av. Mounier 53, box B1.53.17, 1200 Brussels, Belgium.
Université catholique de Louvain, Louvain Drug Research Institute, av. Mounier 72, box B1.72.01, 1200 Brussels, Belgium.
Cell Calcium. 2016 Dec;60(6):373-383. doi: 10.1016/j.ceca.2016.09.002. Epub 2016 Sep 9.
TRP channels are involved in the control of a broad range of cellular functions such as cell proliferation and motility. We investigated the gating mechanism of TRPC1 channel and its role in U251 glioblastoma cells migration in response to chemotaxis by platelet-derived growth factor (PDGF). PDGF induced an influx of Ca that was partially inhibited after pretreatment of the cells with SKI-II, a specific inhibitor of sphingosine kinase producing sphingosine-1-P (S1P). S1P by itself also induced an entry of Ca. Interestingly, PDGF- and S1P-induced entries of Ca were lost in siRNA-TRPC1 treated cells. PDGF-induced chemotaxis of U251 cells was dramatically inhibited in cells treated with SKI-II. This effect was almost completely rescued by addition of synthetic S1P. Chemotaxis was also completely lost in siRNA-TRPC1 treated cells and interestingly, the rescue of migration of cells treated with SKI-II by S1P was dependent on the expression of TRPC1. Immunocytochemistry revealed that, in response to PDGF, TRPC1 translocated from inside of the cell to the front of migration (lamellipodes). This effect seemed PI3K dependent as it was inhibited by cell pre-treatment with LY294002, a PI3-kinase inhibitor. Our results thus identify S1P as a potential activator of TRPC1, a channel involved in cell orientation during chemotaxis by PDGF.
瞬时受体电位（TRP）通道参与多种细胞功能的调控，如细胞增殖和运动。我们研究了TRPC1通道的门控机制及其在U251胶质母细胞瘤细胞响应血小板衍生生长因子（PDGF）趋化作用迁移中的作用。PDGF诱导钙离子内流，在用SKI-II（一种产生鞘氨醇-1-磷酸（S1P）的鞘氨醇激酶特异性抑制剂）预处理细胞后，钙离子内流部分受到抑制。S1P自身也能诱导钙离子内流。有趣的是，在经小干扰RNA（siRNA）-TRPC1处理的细胞中，PDGF和S1P诱导的钙离子内流消失。在用SKI-II处理的细胞中，PDGF诱导的U251细胞趋化作用显著受到抑制。添加合成S1P几乎能完全挽救这种效应。在经siRNA-TRPC1处理的细胞中趋化作用也完全丧失，有趣的是，S1P对用SKI-II处理的细胞迁移的挽救作用依赖于TRPC1的表达。免疫细胞化学显示，响应PDGF时，TRPC1从细胞内部转移到迁移前沿（板状伪足）。这种效应似乎依赖于磷脂酰肌醇-3激酶（PI3K），因为用PI3激酶抑制剂LY294002预处理细胞可抑制该效应。因此，我们的结果确定S1P是TRPC1的潜在激活剂，TRPC1是一种在PDGF趋化作用过程中参与细胞定向的通道。
