May Martin, Kolbe Tanja, Wang Tianbang, Schmidt Gudula, Genth Harald
Institute for Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
J Signal Transduct. 2012;2012:570183. doi: 10.1155/2012/570183. Epub 2012 Jul 5.
Cytotoxic necrotizing factors (CNFs) encompass a class of autotransporter toxins produced by uropathogenic E. coli (CNF1) or Y. pseudotuberculosis (CNFy). CNF toxins deamidate and thereby constitutively activate RhoA, Rac1, and Cdc42. In this study, the effects of CNF1 on cell-matrix adhesion are analysed using functional cell-adhesion assays. CNF1 strongly increased cell-matrix binding of suspended Hela cells and decreased the susceptibly of cells to trypsin-induced cell detachment. Increased cell-matrix binding was also observed upon treatment of Hela cells with isomeric CNFy, that specifically deamidates RhoA. Increased cell-matrix binding thus appears to depend on RhoA deamidation. In contrast, increased cell spreading was specifically observed upon CNF1 treatment, suggesting that it rather depended on Rac1/Cdc42 deamidation. Increased cell-matrix adhesion is further presented to result in reduced cell migration of adherent cells. In contrast, migration of suspended cells was not affected upon treatment with CNF1 or CNFy. CNF1 and CNFy thus reduced cell migration specifically under the condition of pre-established cell-matrix adhesion.
细胞毒性坏死因子（CNFs）包括一类由尿路致病性大肠杆菌（CNF1）或假结核耶尔森菌（CNFy）产生的自转运毒素。CNF毒素使RhoA、Rac1和Cdc42脱酰胺，从而组成性激活它们。在本研究中，使用功能性细胞粘附试验分析了CNF1对细胞-基质粘附的影响。CNF1显著增加了悬浮Hela细胞与细胞基质的结合，并降低了细胞对胰蛋白酶诱导的细胞脱离的敏感性。在用特异性使RhoA脱酰胺的异构体CNFy处理Hela细胞后，也观察到细胞与细胞基质的结合增加。因此，细胞与细胞基质结合的增加似乎依赖于RhoA脱酰胺。相反，在CNF1处理后特异性观察到细胞铺展增加，这表明它更依赖于Rac1/Cdc42脱酰胺。进一步表明，细胞与细胞基质粘附的增加导致贴壁细胞的迁移减少。相反，用CNF1或CNFy处理后，悬浮细胞的迁移不受影响。因此，CNF1和CNFy在预先建立细胞-基质粘附的条件下特异性地减少细胞迁移。
