Nakagawa Ichiro, Inaba Hiroaki, Yamamura Taihei, Kato Takahiro, Kawai Shinji, Ooshima Takashi, Amano Atsuo
Department of Oral Frontier Biology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita-Osaka 565-0871, Japan.
Infect Immun. 2006 Jul;74(7):3773-82. doi: 10.1128/IAI.01902-05.
Porphyromonas gingivalis fimbriae are classified into six types (types I to V and Ib) based on the fimA genes encoding FimA (a subunit of fimbriae), and they play a critical role in bacterial interactions with host tissues. In this study, we compared the efficiencies of P. gingivalis strains with distinct types of fimbriae for invasion of epithelial cells and for degradation of cellular focal adhesion components, paxillin, and focal adhesion kinase (FAK). Six representative strains with the different types of fimbriae were tested, and P. gingivalis with type II fimbriae (type II P. gingivalis) adhered to and invaded epithelial cells at significantly greater levels than the other strains. There were negligible differences in gingipain activities among the six strains; however, type II P. gingivalis apparently degraded intracellular paxillin in association with a loss of phosphorylation 30 min after infection. Degradation was blocked with cytochalasin D or in mutants with fimA disrupted. Paxillin was degraded by the mutant with Lys-gingipain disrupted, and this degradation was prevented by inhibition of Arg-gingipain activity by Nalpha-p-tosyl-l-lysine chloromethyl ketone. FAK was also degraded by type II P. gingivalis. Cellular focal adhesions with green fluorescent protein-paxillin macroaggregates were clearly destroyed, and this was associated with cellular morphological changes and microtubule disassembly. In an in vitro wound closure assay, type II P. gingivalis significantly inhibited cellular migration and proliferation compared to the cellular migration and proliferation observed with the other types. These results suggest that type II P. gingivalis efficiently invades epithelial cells and degrades focal adhesion components with Arg-gingipain, which results in cellular impairment during wound healing and periodontal tissue regeneration.
牙龈卟啉单胞菌菌毛根据编码菌毛亚基FimA的fimA基因分为六种类型（I型至V型和Ib型），它们在细菌与宿主组织的相互作用中起关键作用。在本研究中，我们比较了具有不同类型菌毛的牙龈卟啉单胞菌菌株侵袭上皮细胞以及降解细胞粘着斑成分桩蛋白和粘着斑激酶（FAK）的效率。测试了六种具有不同类型菌毛的代表性菌株，结果显示，具有II型菌毛的牙龈卟啉单胞菌（II型牙龈卟啉单胞菌）粘附并侵袭上皮细胞的水平明显高于其他菌株。这六种菌株的牙龈蛋白酶活性差异可忽略不计；然而，II型牙龈卟啉单胞菌在感染后30分钟明显降解细胞内桩蛋白，并伴随着磷酸化的丧失。细胞松弛素D或fimA基因破坏的突变体可阻断这种降解。桩蛋白被Lys-牙龈蛋白酶破坏的突变体降解，通过Nα-对甲苯磺酰-L-赖氨酸氯甲基酮抑制Arg-牙龈蛋白酶活性可防止这种降解。FAK也被II型牙龈卟啉单胞菌降解。带有绿色荧光蛋白-桩蛋白大聚集体的细胞粘着斑被明显破坏，这与细胞形态变化和微管解聚有关。在体外伤口闭合试验中，与其他类型相比，II型牙龈卟啉单胞菌显著抑制细胞迁移和增殖。这些结果表明，II型牙龈卟啉单胞菌通过Arg-牙龈蛋白酶有效侵袭上皮细胞并降解粘着斑成分，这导致伤口愈合和牙周组织再生过程中的细胞损伤。
