Department for Hospital Infection Control & Research, Institute of Disease Control & Prevention of PLA, Academy of Military Medical Sciences, Beijing, China.
Mol Microbiol. 2011 Aug;81(4):860-80. doi: 10.1111/j.1365-2958.2011.07726.x. Epub 2011 Jul 4.
Internalization of Listeria monocytogenes into non-phagocytic cells is tightly controlled by host cell actin dynamics and cell membrane alterations. However, knowledge about the impact of phosphatidylcholine cleavage driven by host cell phospholipase D (PLD) on Listeria internalization into epithelial cells is limited. Here, we report that L. monocytogenes activates PLD in Vero cells during the internalization. With immunostaining it was shown that both PLD1 and PLD2 surrounded partially or completely the phagocytic cup of most L. monocytogenes. Either up- or down-regulation of PLD expression (activity) diminished Listeria internalization. Both PLD1 and PLD2 in Vero cells were required for efficient Listeria internalization, and could substitute for each other in the regulation of Listeria internalization. Further, exogenous InlB activated host cell PLD1 and PLD2 via the Met receptor, and restored host PLD activation by InlB-deficient L. monocytogenes. InlB-induced PLD activation and Listeria internalization were tightly controlled by phospho-cycling of cofilin. PLD1, but not PLD2, was involved in cofilin-mediated PLD activation and Listeria internalization. These data indicate that cofilin-dependent PLD activation induced by InlB may represent a novel regulation mechanism for efficient Listeria internalization into epithelial cells.
李斯特菌内化进入非吞噬细胞受到宿主细胞肌动蛋白动力学和细胞膜变化的严格控制。然而，宿主细胞磷酯酶 D（PLD）驱动的磷酯酰胆碱裂解对李斯特菌内化进入上皮细胞的影响的知识是有限的。在此，我们报告李斯特菌在内化过程中激活了 Vero 细胞中的 PLD。通过免疫染色表明，PLD1 和 PLD2 部分或完全包围了大多数李斯特菌的吞噬泡。PLD 表达（活性）的上调或下调均降低了李斯特菌的内化。PLD1 和 PLD2 在 Vero 细胞中都对李斯特菌的有效内化是必需的，并且可以在李斯特菌内化的调节中相互替代。此外，外源性 InlB 通过 Met 受体激活宿主细胞的 PLD1 和 PLD2，并通过 InlB 缺陷型李斯特菌恢复宿主 PLD 的激活。InlB 诱导的 PLD 激活和李斯特菌内化受到胞质溶胶蛋白的磷酸化循环的严格控制。PLD1 而不是 PLD2 参与了由 cofilin 介导的 PLD 激活和李斯特菌内化。这些数据表明，InlB 诱导的依赖于 cofilin 的 PLD 激活可能代表了一种有效的李斯特菌内化进入上皮细胞的新调节机制。
