Ferreira Ana S, Silva Inês N, Fernandes Fábio, Pilkington Ruth, Callaghan Máire, McClean Siobhán, Moreira Leonilde M
Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
Centro de Química Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
Infect Immun. 2015 Feb;83(2):812-21. doi: 10.1128/IAI.02713-14. Epub 2014 Dec 8.
Bacterial tyrosine kinases and their cognate protein tyrosine phosphatases are best known for regulating the biosynthesis of polysaccharides. Moreover, their roles in the stress response, DNA metabolism, cell division, and virulence have also been documented. The aim of this study was to investigate the pathogenicity and potential mechanisms of virulence dependent on the tyrosine kinase BceF and phosphotyrosine phosphatase BceD of the cystic fibrosis opportunistic pathogen Burkholderia contaminans IST408. The insertion mutants bceD::Tp and bceF::Tp showed similar attenuation of adhesion and invasion of the cystic fibrosis lung epithelial cell line CFBE41o- compared to the parental strain B. contaminans IST408. In the absence of bceD or bceF genes, B. contaminans also showed a reduction in the ability to translocate across polarized epithelial cell monolayers, demonstrated by a higher transepithelial electrical resistance, reduced flux of fluorescein isothiocyanate-labeled bovine serum albumin, and higher levels of tight junction proteins ZO-1, occludin, and claudin-1 present in monolayers exposed to these bacterial mutants. Furthermore, bceD::Tp and bceF::Tp mutants induced lower levels of interleukin-6 (IL-6) and IL-8 release than the parental strain. In conclusion, although the mechanisms of pathogenicity dependent on BceD and BceF are not understood, these proteins contribute to the virulence of Burkholderia by enhancement of cell attachment and invasion, disruption of epithelial integrity, and modulation of the proinflammatory response.
细菌酪氨酸激酶及其同源蛋白酪氨酸磷酸酶最为人所知的是调节多糖的生物合成。此外，它们在应激反应、DNA代谢、细胞分裂和毒力方面的作用也有文献记载。本研究的目的是调查囊性纤维化机会致病菌污染洋葱伯克霍尔德菌IST408的酪氨酸激酶BceF和磷酸酪氨酸磷酸酶BceD所依赖的致病性及潜在毒力机制。与亲本菌株污染洋葱伯克霍尔德菌IST408相比，插入突变体bceD::Tp和bceF::Tp在囊性纤维化肺上皮细胞系CFBE41o-上的黏附和侵袭能力表现出类似的减弱。在缺失bceD或bceF基因的情况下，污染洋葱伯克霍尔德菌跨极化上皮细胞单层转运的能力也有所降低，表现为跨上皮电阻更高、异硫氰酸荧光素标记的牛血清白蛋白通量降低，以及暴露于这些细菌突变体的单层中紧密连接蛋白ZO-1、闭合蛋白和claudin-1水平更高。此外，bceD::Tp和bceF::Tp突变体诱导释放的白细胞介素-6（IL-6）和IL-8水平低于亲本菌株。总之，尽管依赖BceD和BceF的致病机制尚不清楚，但这些蛋白通过增强细胞黏附和侵袭、破坏上皮完整性以及调节促炎反应，对伯克霍尔德菌的毒力有贡献。
