title: Neisseria gonorrhoeae infection causes DNA damage and affects the expression of p21, p27 and p53 in non-tumor epithelial cells.
abstract: The constant shedding and renewal of epithelial cells maintain the protection of epithelial barriers. Interference with the processes of host cell-cycle regulation and barrier integrity permits the bacterial pathogen Neisseria gonorrhoeae to effectively colonize and invade epithelial cells. Here, we show that a gonococcal infection causes DNA damage in human non-tumor vaginal VK2/E6E7 cells with an increase of 700 DNA strand breaks per cell per hour as detected by an alkaline DNA unwinding assay. Infected cells exhibited elevated levels of DNA double-strand breaks, as indicated by a more than 50% increase in cells expressing DNA damage-response protein 53BP1-positive foci that co-localized with phosphorylated histone H2AX (γH2AX). Furthermore, infected cells abolished their expression of the tumor protein p53 and induced an increase in the expression of cyclin-dependent kinase inhibitors p21 and p27 to 2.6-fold and 4.2-fold of controls, respectively. As shown by live-cell microscopy, flow cytometry assays, and BrdU incorporation assays, gonococcal infection slowed the host cell-cycle progression mainly by impairing progression through the G2 phase. Our findings show new cellular players that are involved in the control of the human cell cycle during gonococcal infection and the potential of bacteria to cause cellular abnormalities.
authors.affiliation: Department of Genetics, Microbiology and Toxicology, Svante Arrhenius väg 20C, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Vielfort
authors.forename: Niklas
authors.initials: N
authors.lastname: Söderholm
authors.forename: Linda
authors.initials: L
authors.lastname: Weyler
authors.forename: Daniel
authors.initials: D
authors.lastname: Vare
authors.forename: Sonja
authors.initials: S
authors.lastname: Löfmark
authors.forename: Helena
authors.initials: H
authors.lastname: Aro
mesh_terms: D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage / Q000235:genetics*; D004847:Epithelial Cells / Q000378:metabolism* / Q000382:microbiology*; D005434:Flow Cytometry; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000472:pathogenicity* / Q000502:physiology; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; C413374:p27 antigen