Division of Microbiology and Infection Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Temporomandibular Joint Clinic, Niigata University Medical and Dental Hospital, Niigata, Japan.
Division of Microbiology and Infection Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Research Centre for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Cell Immunol. 2018 Mar;325:14-22. doi: 10.1016/j.cellimm.2018.01.006. Epub 2018 Jan 16.
Streptococcus pneumoniae is a leading cause of bacterial pneumonia. Our previous study suggested that S. pneumoniae autolysis-dependently releases intracellular pneumolysin, which subsequently leads to lung injury. In this study, we hypothesized that pneumococcal autolysis induces the leakage of additional intracellular molecules that could increase the pathogenicity of S. pneumoniae. Liquid chromatography tandem-mass spectrometry analysis identified that chaperone protein DnaK, elongation factor Tu (EF-Tu), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were released with pneumococcal DNA by autolysis. We demonstrated that recombinant (r) DnaK, rEF-Tu, and rGAPDH induced significantly higher levels of interleukin-6 and tumor necrosis factor production in peritoneal macrophages and THP-1-derived macrophage-like cells via toll-like receptor 4. Furthermore, the DNA-binding activity of these proteins was confirmed by surface plasmon resonance assay. We demonstrated that pneumococcal DnaK, EF-Tu, and GAPDH induced the production of proinflammatory cytokines in macrophages, and might cause host tissue damage and affect the development of pneumococcal diseases.
肺炎链球菌是细菌性肺炎的主要病因。我们之前的研究表明，肺炎链球菌通过自溶作用释放出胞内肺炎球菌溶血素，进而导致肺部损伤。在本研究中，我们假设肺炎链球菌自溶会诱导其他胞内分子的渗漏，从而增加肺炎链球菌的致病性。液相色谱串联质谱分析鉴定出伴侣蛋白 DnaK、延伸因子 Tu（EF-Tu）和甘油醛-3-磷酸脱氢酶（GAPDH）与肺炎链球菌 DNA 一起通过自溶作用释放。我们证明，重组（r）DnaK、rEF-Tu 和 rGAPDH 通过 Toll 样受体 4 诱导腹腔巨噬细胞和 THP-1 衍生的巨噬样细胞中白细胞介素 6 和肿瘤坏死因子的产生水平显著升高。此外，通过表面等离子体共振分析证实了这些蛋白质的 DNA 结合活性。我们证明肺炎链球菌 DnaK、EF-Tu 和 GAPDH 诱导巨噬细胞产生促炎细胞因子，可能导致宿主组织损伤并影响肺炎球菌病的发展。
