Exit of intracellular Porphyromonas gingivalis from gingival epithelial cells is mediated by endocytic recycling pathway
Exit of intracellular Porphyromonas gingivalis from gingival epithelial cells is mediated by endocytic recycling pathway
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DOI：
10.1111/j.1462-5822.2010.01564.x
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发表时间：
2011-05-01
影响因子：
3.4
通讯作者：
Amano, Atsuo
中科院分区：
文献类型：
--
作者：
Takeuchi, Hiroki;Furuta, Nobumichi;Amano, Atsuo
牙龈上皮细胞作为一种天然宿主防御系统，可以防止牙周细菌的入侵。然而，最著名的牙周病原体牙龈卟啉单胞菌可以进入牙龈上皮细胞，并通过上皮屏障进入更深的组织。然而，人们对这种病原体如何从被感染的细胞中退出并进一步跨细胞传播知之甚少。本研究旨在阐明牙龈假单胞菌从永生化人牙龈上皮细胞中退出的细胞机制。结果表明，牙龈卟啉卟啉菌内化的早期胞内体为EEA1和转铁蛋白受体的FYVE结构域阳性，大约一半胞内菌被分选为溶酶室，包括自溶酶体和晚期胞内体/溶酶体，而相当一部分胞内菌被分选为Rab11-和rala阳性的再循环胞内体。抑制实验表明，细菌的退出依赖于肌动蛋白聚合、脂筏和微管组装。Rab11、RalA和胞囊复合物亚基（Sec5、Sec6和Exo84）的显性阴性形式和RNAi敲低显著干扰了牙龈假单胞菌的退出。这些结果强烈表明，细胞内牙龈假单胞菌利用循环途径从感染细胞进入邻近细胞，作为细胞间扩散的一种机制。
P>Gingival epithelial cells function as an innate host defence system to prevent intrusion by periodontal bacteria. Nevertheless, Porphyromonas gingivalis, the most well-known periodontal pathogen, can enter gingival epithelial cells and pass through the epithelial barrier into deeper tissues. However, it is poorly understood how this pathogen exits from infected cells for further transcellular spreading. The present study was performed to elucidate the cellular machinery exploited by P. gingivalis to exit from immortalized human gingival epithelial cells. P. gingivalis was shown to be internalized with early endosomes positive for the FYVE domain of EEA1 and transferrin receptor, and about half of the intracellular bacteria were then sorted to lytic compartments, including autolysosomes and late endosomes/lysosomes, while a considerable number of the remaining organisms were sorted to Rab11- and RalA-positive recycling endosomes. Inhibition experiments revealed that bacterial exit was dependent on actin polymerization, lipid rafts and microtubule assembly. Dominant negative forms and RNAi knockdown of Rab11, RalA and exocyst complex subunits (Sec5, Sec6 and Exo84) significantly disturbed the exit of P. gingivalis. These results strongly suggest that the recycling pathway is exploited by intracellular P. gingivalis to exit from infected cells to neighbouring cells as a mechanism of cell-to-cell spreading.