Characterization of Tigurilysin, a Novel Human CD59-Specific Cholesterol-Dependent Cytolysin, Reveals a Role for Host Specificity in Augmenting Toxin Activity.

Autor:	Shahi I; New York University Grossman School of Medicine, Department of Pediatrics, New York, NY., Dongas SA; New York University Grossman School of Medicine, Department of Pediatrics, New York, NY., Ilmain JK; New York University Grossman School of Medicine, Department of Microbiology, New York, NY., Torres VJ; New York University Grossman School of Medicine, Department of Microbiology, New York, NY., Ratner AJ; New York University Grossman School of Medicine, Department of Pediatrics, New York, NY.; New York University Grossman School of Medicine, Department of Microbiology, New York, NY.
Jazyk:	angličtina
Zdroj:	BioRxiv : the preprint server for biology [bioRxiv] 2023 Jul 25. Date of Electronic Publication: 2023 Jul 25.
DOI:	10.1101/2023.06.21.545930
Abstrakt:	Cholesterol dependent cytolysins (CDCs) are a large family of pore forming toxins, produced by numerous gram-positive pathogens. CDCs depend on host membrane cholesterol for pore formation; some CDCs also require surface associated human CD59 (hCD59) for binding, conferring specificity for human cells. We purified a recombinant version of a putative CDC encoded in the genome of Streptococcus oralis subsp. tigurinus , tigurilysin (TGY), and used CRISPR/Cas9 to construct hCD59 knockout (KO) HeLa and JEG-3 cell lines. Cell viability assays with TGY on WT and hCD59 KO cells showed that TGY is a hCD59-dependent CDC. Two variants of TGY exist among S. oralis subsp. tigurinus genomes, only one of which is functional. We discovered that a single amino acid change between these two TGY variants determines its activity. Flow cytometry and oligomerization western blots revealed that the single amino acid difference between the two TGY isoforms disrupts host cell binding and oligomerization. Furthermore, experiments with hCD59 KO cells and cholesterol depleted cells demonstrated that TGY is fully dependent on both hCD59 and cholesterol for activity, unlike other known hCD59-dependent CDCs. Using full-length CDCs and toxin constructs differing only in the binding domain, we determined that having hCD59-dependence leads to increased lysis efficiency, conferring a potential advantage to organisms producing hCD59-dependent CDCs. Importance: Cholesterol dependent cytolysins (CDCs) are produced by a variety of disease-causing bacteria, and may play a significant role in pathogenesis. Understanding CDC mechanisms of action provides useful information for developing anti-virulence strategies against bacteria that utilize CDCs and other pore-forming toxins in pathogenesis. This study describes for the first time a novel human-specific CDC with an atypical pore forming mechanism compared to known CDCs. In addition, this study demonstrates that human-specificity potentially confers increased lytic efficiency to CDCs. These data provide a possible explanation for the selective advantage of developing hCD59-dependency in CDCs and the consequent host restriction.
Databáze:	MEDLINE
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