Cell. 2022 Mar 02. pii: S0092-8674(22)00142-8. [Epub ahead of print]
Xiaozhe Xiong,
Songhai Tian,
Pan Yang,
Francois Lebreton,
Huan Bao,
Kuanwei Sheng,
Linxiang Yin,
Pengsheng Chen,
Jie Zhang,
Wanshu Qi,
Jianbin Ruan,
Hao Wu,
Hong Chen,
David T Breault,
Hao Wu,
Ashlee M Earl,
Michael S Gilmore,
Jonathan Abraham,
Min Dong.
Enterococci are a part of human microbiota and a leading cause of multidrug resistant infections. Here, we identify a family of Enterococcus pore-forming toxins (Epxs) in E. faecalis, E. faecium, and E. hirae strains isolated across the globe. Structural studies reveal that Epxs form a branch of β-barrel pore-forming toxins with a β-barrel protrusion (designated the top domain) sitting atop the cap domain. Through a genome-wide CRISPR-Cas9 screen, we identify human leukocyte antigen class I (HLA-I) complex as a receptor for two members (Epx2 and Epx3), which preferentially recognize human HLA-I and homologous MHC-I of equine, bovine, and porcine, but not murine, origin. Interferon exposure, which stimulates MHC-I expression, sensitizes human cells and intestinal organoids to Epx2 and Epx3 toxicity. Co-culture with Epx2-harboring E. faecium damages human peripheral blood mononuclear cells and intestinal organoids, and this toxicity is neutralized by an Epx2 antibody, demonstrating the toxin-mediated virulence of Epx-carrying Enterococcus.
Keywords: CRISPR screen; E. faecalis; E. faecium; E. hirae; Enterococcus; HLA-I; MHC-I; bacterial toxin; interferon; pore-forming toxin