Chitin Attenuates Expression of Listeria monocytogenes Virulence Genes in vitro .

Autor:	Villoria Recio M; Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, Food Safety and Zoonoses-University of Copenhagen, Frederiksberg, Denmark.; Alimentary Pharmabotic Centre Microbiome Ireland, University College Cork, Cork, Ireland.; School of Microbiology, University College Cork, Cork, Ireland., Lee BH; Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France., Lillebæk EMS; Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark., Kallipolitis BH; Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark., Gahan CGM; Alimentary Pharmabotic Centre Microbiome Ireland, University College Cork, Cork, Ireland.; School of Microbiology, University College Cork, Cork, Ireland., Ingmer H; Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, Food Safety and Zoonoses-University of Copenhagen, Frederiksberg, Denmark., Larsen MH; Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, Food Safety and Zoonoses-University of Copenhagen, Frederiksberg, Denmark.
Jazyk:	angličtina
Zdroj:	Frontiers in microbiology [Front Microbiol] 2020 Dec 03; Vol. 11, pp. 588906. Date of Electronic Publication: 2020 Dec 03 (Print Publication: 2020).
DOI:	10.3389/fmicb.2020.588906
Abstrakt:	External signals are crucial for bacteria to sense their immediate environment and fine-tune gene expression accordingly. The foodborne pathogen Listeria monocytogenes senses a range of environmental cues in order to activate or deactivate the virulence-inducing transcriptional factor PrfA during transition between infectious and saprophytic lifecycles. Chitin is an abundant biopolymer formed from linked β-(1-4)-N-acetyl-D-glucosamine residues associated with fungi, the exoskeleton of insects and often incorporated into foods as a thickener or stabilizer. L. monocytogenes evolved to hydrolyse chitin, presumably, to facilitate nutrient acquisition from competitive environments such as soil where the polymer is abundant. Since mammals do not produce chitin, we reasoned that the polymer could serve as an environmental signal contributing to repression of L. monocytogenes PrfA-dependent expression. This study shows a significant downregulation of the core PrfA-regulon during virulence-inducing conditions in vitro in the presence of chitin. Our data suggest this phenomenon occurs through a mechanism that differs from PTS-transport of oligosaccharides generated from either degradation or chitinase-mediated hydrolysis of the polymer. Importantly, an indication that chitin can repress virulence expression of a constitutively active PrfA ∗ mutant is shown, possibly mediated via a post-translational modification inhibiting PrfA ∗ activity. To our knowledge, this is the first time that chitin is reported as a molecule with anti-virulence properties against a pathogenic bacterium. Thus, our findings identify chitin as a signal which may downregulate the virulence potential of the pathogen and may provide an alternative approach toward reducing disease risk. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2020 Villoria Recio, Lee, Lillebæk, Kallipolitis, Gahan, Ingmer and Larsen.)
Databáze:	MEDLINE
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