Yuan Lihui, Rodrigues Paulo H, Bélanger Myriam, Dunn William A, Progulske-Fox Ann
Department of Oral Biology, College of Dentistry and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA.
Department of Anatomy and Cell Biology, College of Medicine and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA.
Microbiology (Reading). 2008 Apr;154(Pt 4):1161-1169. doi: 10.1099/mic.0.2007/015131-0.
HtrA is a heat-stress protein that functions both as a chaperone and as a serine protease. HtrA has been shown in several organisms to be involved in responses to stressful environmental conditions and involvement of HtrA in virulence has been reported in pathogenic species. A Porphyromonas gingivalis htrA mutant demonstrated no significant difference to the W83 parent strain when subjected to high temperature and pH values from 3 to 11. However, the htrA mutant showed increased sensitivity to H(2)O(2). Cell invasion assays indicated that the total interaction (adherence) with KB cells, human coronary artery endothelial cells and gingival epithelial cells (GEC) was the same for both the wild-type and the htrA mutant. However, the htrA mutant showed increased invasion in KB cells and GEC. Microarray experiments indicated that a total of 253 genes were differentially regulated in the htrA mutant, including a group of stress-related genes, which might be responsible for the observed decreased resistance to H(2)O(2). In animal experiments, a competition assay showed that the htrA mutant did not survive as well as the wild-type. In another in vivo assay, fewer mice infected with the htrA mutant died than mice infected with W83, suggesting that the htrA gene is virulence-related. These data indicate that the htrA gene in P. gingivalis does not relate to stress conditions such as high temperature and pH, but rather to H(2)O(2) stress. The htrA gene also appears to be important for virulence and survival in in vivo animal models.
HtrA是一种热应激蛋白，兼具伴侣蛋白和丝氨酸蛋白酶的功能。在多种生物体中，HtrA已被证明参与对应激环境条件的反应，并且在致病物种中也有报道称HtrA与毒力有关。牙龈卟啉单胞菌的htrA突变体在经受高温以及pH值从3到11的环境时，与W83亲本菌株相比没有显著差异。然而，htrA突变体对H₂O₂表现出更高的敏感性。细胞侵袭试验表明，野生型和htrA突变体与KB细胞、人冠状动脉内皮细胞和牙龈上皮细胞（GEC）的总相互作用（黏附）是相同的。然而，htrA突变体在KB细胞和GEC中的侵袭能力增强。微阵列实验表明，htrA突变体中共有253个基因受到差异调节，包括一组与应激相关的基因，这可能是观察到的对H₂O₂抗性降低的原因。在动物实验中，竞争试验表明htrA突变体的存活能力不如野生型。在另一项体内试验中，感染htrA突变体的小鼠死亡数量比感染W83的小鼠少，这表明htrA基因与毒力有关。这些数据表明，牙龈卟啉单胞菌中的htrA基因与高温和pH等应激条件无关，而是与H₂O₂应激有关。htrA基因在体内动物模型的毒力和存活方面似乎也很重要。
