title: Role ofyqiCin the Pathogenicity ofSalmonellaand Innate Immune Responses of Human Intestinal Epithelium.
abstract: TheyqiCgene ofSalmonella entericaserovar Typhimurium (S. Typhimurium) regulates bacterial growth at different temperatures and mice survival after infection. However, the role ofyqiCin bacterial colonization and host immunity remains unknown. We infected human LS174T, Caco-2, HeLa, and THP-1 cells withS. Typhimurium wild-type SL1344, itsyqiCmutant, and its complemented strain. Bacterial colonization and internalization in the four cell lines significantly reduced onyqiCdepletion. Post-infection production of interleukin-8 and human β-defensin-3 in LS174T cells significantly reduced because ofyqiCdeleted inS. Typhimurium. The phenotype ofyqiC mutant exhibited few and short flagella, fimbriae on the cell surface, enhanced biofilm formation, upregulated type-1 fimbriae expression, and reduced bacterial motility. Type-1 fimbriae, flagella, SPI-1, and SPI-2 gene expression was quantified using real-time PCR. The data show that deletion ofyqiCupregulatedfimAandfimZexpression and downregulatedflhD, fliZ, invA, andsseBexpression. Furthermore, thin-layer chromatography and high-performance liquid chromatography revealed the absence of menaquinone in theyqiCmutant, thus validating the importance ofyqiCin the bacterial electron transport chain. Therefore, YqiC can negatively regulate FimZ for type-1 fimbriae expression and manipulate the functions of its downstream virulence factors including flagella, SPI-1, and SPI-2 effectors.
authors: Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan.
authors: Ke-Chuan
authors: KC
authors: Wang
authors: Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology Taipei, Taiwan.
authors: Chih-Hung
authors: CH
authors: Huang
authors: Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of TechnologyTaipei, Taiwan.
authors: Shih-Min
authors: SM
authors: Ding
authors: Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology Taipei, Taiwan.
authors: Ching-Kuo
authors: CK
authors: Chen
authors: Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of TechnologyTaipei, Taiwan; Institute of Biomedical Engineering and Nanomedicine - National Health Research InstitutesZhunan, Taiwan.
authors: Hsu-Wei
authors: HW
authors: Fang
authors: Department of Surgery, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Surgery, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan.
authors: Ming-Te
authors: MT
authors: Huang
authors: Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan.
authors: Shiuh-Bin
authors: SB
authors: Fang
keywords: Salmonella Typhimurium; bacterial colonization; flagella; human β-defensin-3; interleukin-8; menaquinone; type-1 fimbriae; yqiC