Fatty Acids Abolish Shigella Virulence by Inhibiting Its Master Regulator, VirF.

Autor:	Trirocco R; Institute Pasteur Italia, Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy., Pasqua M; Institute Pasteur Italia, Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy., Tramonti A; Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy., Grossi M; Institute Pasteur Italia, Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy., Colonna B; Institute Pasteur Italia, Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy., Paiardini A; Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy., Prosseda G; Institute Pasteur Italia, Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy.
Jazyk:	angličtina
Zdroj:	Microbiology spectrum [Microbiol Spectr] 2023 Jun 15; Vol. 11 (3), pp. e0077823. Date of Electronic Publication: 2023 May 04.
DOI:	10.1128/spectrum.00778-23
Abstrakt:	The pathogenicity of Shigella , the intracellular pathogen responsible for human bacillary dysentery, depends on a coordinated and tightly regulated expression of its virulence determinants. This is the result of a cascade organization of its positive regulators, with VirF, a transcriptional activator belonging to the AraC-XylS family, in a pivotal position. VirF itself is submitted to several well-known regulations at the transcriptional level. In this work, we present evidence for a novel posttranslational regulatory mechanism of VirF mediated by the inhibitory interaction with specific fatty acids. By homology modeling and molecular docking analyses, we identify a jelly roll motif in the structure of ViF capable of interacting with medium-chain saturated and long-chain unsaturated fatty acids. In vitro and in vivo assays show that capric, lauric, myristoleic, palmitoleic, and sapienic acids interact effectively with the VirF protein, abolishing its transcription-promoting activity. This silences the virulence system of Shigella , leading to a drastic reduction in its ability to invade epithelial cells and proliferate in their cytoplasm. IMPORTANCE In the absence of a valid vaccine, the main therapeutic approach currently used to treat shigellosis is based on the use of antibiotics. The emergence of antibiotic resistance jeopardizes the future effectiveness of this approach. The importance of the present work resides both in the identification of a new level of posttranslational regulation of the Shigella virulence system and in the characterization of a mechanism offering new opportunities for the design of antivirulence compounds, which may change the treatment paradigm of Shigella infections by limiting the emergence of antibiotic-resistant bacteria. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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