Host-Receptor Post-Translational Modifications Refine Staphylococcal Leukocidin Cytotoxicity.

Angelino T Tromp,Anneroos Velthuizen,Joris P Jansen,Robert Jan Lebbink,András N Spaan,Pieter-Jan A Haas,Michael Boettcher,Michael T Mcmanus,Carla J.C De Haas,Bart W Bardoel,Jos A.G Van Strijp,Michiel Van Gent,Kok P.M Van Kessel,Lisette M Scheepmaker

doi:10.3390/toxins12020106

Abstract

Staphylococcal bi-component pore-forming toxins, also known as leukocidins, target and lyse human phagocytes in a receptor-dependent manner. S-components of the leukocidins Panton-Valentine leukocidin (PVL), γ-haemolysin AB (HlgAB) and CB (HlgCB), and leukocidin ED (LukED) specifically employ receptors that belong to the class of G-protein coupled receptors (GPCRs). Although these receptors share a common structural architecture, little is known about the conserved characteristics of the interaction between leukocidins and GPCRs. In this study, we investigated host cellular pathways contributing to susceptibility towards S. aureus leukocidin cytotoxicity. We performed a genome-wide CRISPR/Cas9 library screen for toxin-resistance in U937 cells sensitized to leukocidins by ectopic expression of different GPCRs. Our screen identifies post-translational modification (PTM) pathways involved in the sulfation and sialylation of the leukocidin-receptors. Subsequent validation experiments show differences in the impact of PTM moieties on leukocidin toxicity, highlighting an additional layer of refinement and divergence in the staphylococcal host-pathogen interface. Leukocidin receptors may serve as targets for anti-staphylococcal interventions and understanding toxin-receptor interactions will facilitate the development of innovative therapeutics. Variations in the genes encoding PTM pathways could provide insight into observed differences in susceptibility of humans to infections with S. aureus.

Highlights

Staphylococcus aureus is a Gram-positive bacterium that colonizes the skin and anterior nares of20%–30% of the general human population [1]
To identify host factors involved in Panton-Valentine leukocidin (PVL)- and HlgCB-mediated susceptibility of human phagocytes, a genome-wide CRISPR/Cas9 library screen for both PVL- and HlgCB resistance was set up in human
We used a genome-wide CRISPR/Cas9 based approach to screen for cellular factors involved in susceptibility towards G-protein coupled receptors (GPCRs)-targeting leukocidins, and identify two post-translational modification (PTM) pathways driving GPCR-mediated susceptibility of phagocytes to leukocidins

Summary

Introduction

Staphylococcus aureus is a Gram-positive bacterium that colonizes the skin and anterior nares of20%–30% of the general human population [1]. Staphylococcus aureus is a Gram-positive bacterium that colonizes the skin and anterior nares of. S. aureus causes a variety of diseases, ranging from superficial skin and soft tissue infections to severe invasive infections with a poor prognosis and high mortality [2]. S. aureus is faced with the host humoral and cellular innate immune response [3]. S. aureus, in return, secretes an arsenal of virulence factors to circumvent host defenses and to avoid killing by phagocytes [4]. An important group of S. aureus virulence factors, the leukocidins, target and lyse host phagocytes [5,6]. S. aureus leukocidins are bi-component beta-barrel pore-forming toxins [6]. Human S. aureus isolates secrete up to five leukocidins: Panton-Valentine leukocidin (PVL), γ-haemolysin AB (HlgAB) and CB (HlgCB), leukocidin ED (LukED) and leukocidin

Methods

Results

Conclusion