title: Type VI secretion system contributes to Enterohemorrhagic Escherichia coli virulence by secreting catalase against host reactive oxygen species (ROS).
abstract: Enterohemorrhagic Escherichia coli (EHEC) is one major type of contagious and foodborne pathogens. The type VI secretion system (T6SS) has been shown to be involved in the bacterial pathogenicity and bacteria-bacteria competition. Here, we show that EHEC could secrete a novel effector KatN, a Mn-containing catalase, in a T6SS-dependent manner. Expression of katN is promoted by RpoS and OxyR and repressed by H-NS, and katN contributes to bacterial growth under oxidative stress in vitro. KatN could be secreted into host cell cytosol after EHEC is phagocytized by macrophage, which leads to decreased level of intracellular reactive oxygen species (ROS) and facilitates the intramacrophage survival of EHEC. Finally, animal model results show that the deletion mutant of T6SS was attenuated in virulence compared with the wild type strain, while the deletion mutant of katN had comparable virulence to the wild type strain. Taken together, our findings suggest that EHEC could sense oxidative stress in phagosome and decrease the host cell ROS by secreting catalase KatN to facilitate its survival in the host cells.
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Baoshan
authors.initials: B
authors.lastname: Wan
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Qiufen
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Jinjing
authors.initials: J
authors.lastname: Ni
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Shuxian
authors.identifier: 0000-0002-3290-5889
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Donghua
authors.initials: D
authors.lastname: Wen
authors.affiliation: State Key Laboratory for Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.|College of Biological Engineering, Zhejiang University of Technology, Hangzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Haihan
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Ping
authors.initials: P
authors.lastname: He
authors.affiliation: State Key Laboratory for Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Ou
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Tao
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Qihui
authors.identifier: 0000-0003-1783-4696
authors.initials: Q
authors.lastname: Teng
authors.affiliation: Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Wu
authors.affiliation: Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.|Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Yu-Feng
authors.identifier: 0000-0003-0849-3797
authors.initials: YF
authors.lastname: Yao
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism*; D004195:Disease Models, Animal; D054324:Enterohemorrhagic Escherichia coli / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000378:metabolism / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D054884:Host-Pathogen Interactions / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D000069376:Type VI Secretion Systems / Q000378:metabolism*; D014774:Virulence / Q000502:physiology
chemical_list: D029968:Escherichia coli Proteins; D017382:Reactive Oxygen Species; D000069376:Type VI Secretion Systems; D002374:Catalase