YjcC, a c-di-GMP phosphodiesterase protein, regulates the oxidative stress response and virulence of Klebsiella pneumoniae CG43

• Published in: PloS one Vol. 8; no. 7; p. e66740
• Main Authors: Huang, Ching-Jou, Wang, Zhe-Chong, Huang, Hsi-Yuan, Huang, Hsien-Da, Peng, Hwei-Ling
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 23-07-2013; Public Library of Science (PLoS)
• Subjects: Analysis; Animals; Bacteria; Bacterial Capsules - drug effects; Bacterial Capsules - metabolism; Bacterial Proteins - metabolism; Base Sequence; Biofilms; Biofilms - drug effects; Bioinformatics; Biology; Biosynthesis; Cell surface; Clonal deletion; Cloning; Cyclic GMP - analogs & derivatives; Cyclic GMP - metabolism; Deletion mutant; Down-Regulation - drug effects; Down-Regulation - genetics; E coli; Energy metabolism; Escherichia coli; Female; Fimbriae, Bacterial - drug effects; Fimbriae, Bacterial - metabolism; Gene Deletion; Gene expression; Gene Expression Regulation, Bacterial - drug effects; Gene regulation; Genes; Glutaredoxin; Heat shock proteins; Herbicides; Hydrogen peroxide; In vivo methods and tests; Klebsiella; Klebsiella Infections - microbiology; Klebsiella Infections - pathology; Klebsiella pneumoniae; Klebsiella pneumoniae - enzymology; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - pathogenicity; Klebsiella pneumoniae - physiology; Metabolism; Mice; Mice, Inbred BALB C; Molecular Sequence Data; Motility; Oxidation; Oxidative Stress; Oxygen; Paraquat; Paraquat - toxicity; Phosphodiesterase; Phosphoric Diester Hydrolases - metabolism; Physiological aspects; Pili; Pilin; Plasmids; Pneumonia; Polysaccharides; Polysaccharides, Bacterial - metabolism; Proteins; Reactive oxygen species; Recombinant proteins; Signaling; SoxS protein; Stress response; Surface structure; Thioredoxin; Transcription; Transcriptome - genetics; Up-Regulation - drug effects; Up-Regulation - genetics; Virulence; Virulence - drug effects; China; Taiwan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0066740

This study shows that the expression of yjcC, an in vivo expression (IVE) gene, and the stress response regulatory genes soxR, soxS, and rpoS are paraquat inducible in Klebsiella pneumoniae CG43. The deletion of rpoS or soxRS decreased yjcC expression, implying an RpoS- or SoxRS-dependent control. After paraquat or H2O2 treatment, the deletion of yjcC reduced bacterial survival. These effects could be complemented by introducing the ΔyjcC mutant with the YjcC-expression plasmid pJR1. The recombinant protein containing only the YjcC-EAL domain exhibited phosphodiesterase (PDE) activity; overexpression of yjcC has lower levels of cyclic di-GMP. The yjcC deletion mutant also exhibited increased reactive oxygen species (ROS) formation, oxidation damage, and oxidative stress scavenging activity. In addition, the yjcC deletion reduced capsular polysaccharide production in the bacteria, but increased the LD50 in mice, biofilm formation, and type 3 fimbriae major pilin MrkA production. Finally, a comparative transcriptome analysis showed 34 upregulated and 29 downregulated genes with the increased production of YjcC. The activated gene products include glutaredoxin I, thioredoxin, heat shock proteins, chaperone, and MrkHI, and proteins for energy metabolism (transporters, cell surface structure, and transcriptional regulation). In conclusion, the results of this study suggest that YjcC positively regulates the oxidative stress response and mouse virulence but negatively affects the biofilm formation and type 3 fimbriae expression by altering the c-di-GMP levels after receiving oxidative stress signaling inputs.