Identification of OmpU of Vibrio vulnificus as a fibronectin-binding protein and its role in bacterial pathogenesis
Identification of OmpU of Vibrio vulnificus as a fibronectin-binding protein and its role in bacterial pathogenesis
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DOI：
10.1128/iai.00171-06
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发表时间：
2006-10-01
影响因子：
3.1
通讯作者：
Park, Soon-Jung
中科院分区：
文献类型：
--
作者：
Goo, Sung Young;Lee, Hyun-Ju;Park, Soon-Jung
创伤弧菌是一种致病性细菌，可引起胃肠炎和原发性败血症。为了确定参与微生物粘附宿主细胞的因素，我们研究了能够与纤连蛋白结合的细菌蛋白，纤连蛋白是哺乳动物细胞的细胞外基质的主要成分之一。从创伤弧菌提取物中纯化了一种分子量约为35 kDa的蛋白质，该蛋白质具有与固定化纤连蛋白结合的特性。该蛋白被鉴定为OmpU，是创伤弧菌的主要外膜蛋白之一。在使用固定化纤连蛋白的结合试验中，与纤连蛋白结合的ompU突变细胞的数量仅为与纤连蛋白结合的野生型细胞的4%。此外，外源性添加抗OmpU抗体导致野生型创伤弧菌粘附纤连蛋白的能力降低。ompU突变体在其对RGD三肽的粘附性（野生型对RGD的粘附性的5%）、对HEp-2细胞的细胞粘附性（野生型对HEp-2的粘附性的7%）、对细胞培养物的细胞毒性（野生型的细胞毒性的39%）和小鼠死亡率（在50%致死剂量下增加10倍）方面也有缺陷。与完整ompU基因互补的ompU突变体恢复了其粘附纤连蛋白、RGD三肽和HEp-2细胞的能力;对HEp-2细胞的细胞毒性;和小鼠致死性。本研究表明OmpU是创伤弧菌粘附宿主细胞的重要毒力因子。
Vibrio vulnificus is a pathogenic bacterium that causes gastroenteritis and primary septicemia. To identify factors involved in microbial adherence to the host cells, we investigated bacterial proteins capable of binding to fibronectin, one of the main components comprised of the extracellular matrix of mammalian cells. A protein of similar to 35 kDa was purified from the extracts of V. vulnificus by its property to bind to immobilized fibronectin. This protein was identified as OmpU, one of the major outer membrane proteins of V. vulnificus. In binding assays using immobilized fibronectin, the number of ompU mutant cells bound to fibronectin was only 4% of that of wild-type cells bound to fibronectin. In addition, the exogenous addition of antibodies against OmpU resulted in a decreased ability of wild-type V. vulnificus to adhere to fibronectin. The ompU mutant was also defective in its adherence to RGD tripeptide (5% of the adherence of the wild type to RGD), cytoadherence to HEp-2 cells (7% of the adherence of the wild type to HEp-2), cytotoxicity to cell cultures (39% of the cytotoxicity of the wild type), and mortality in mice (10-fold increase in the 50% lethal dose). The ompU mutant complemented with the intact ompU gene restored its abilities for adherence to fibronectin, RGD tripeptide, and HEp-2 cells; cytotoxicity to HEp-2 cells; and mouse lethality. This study indicates that OmpU is an important virulence factor involved in the adherence of V. vulnificus to the host cells.