Hydrogen Sulfide and Reactive Sulfur Species Impact Proteome S-Sulfhydration and Global Virulence Regulation in Staphylococcus aureus

Abstract

Hydrogen sulfide (H2S) is thought to protect bacteria from oxidative stress, but a comprehensive understanding of its function in bacteria is largely unexplored. In this study, we show that the human pathogen Staphylococcus aureus (S. aureus) harbors significant effector molecules of H2S signaling, reactive sulfur species (RSS), as low molecular weight persulfides of bacillithiol, coenzyme A, and cysteine, and significant inorganic polysulfide species. We find that proteome S- sulfhydration, a post-translational modification (PTM) in H2S signaling, is widespread in S. aureus. RSS levels modulate the expression of secreted virulence factors and the cytotoxicity of the secretome, consistent with an S-sulfhydration-dependent inhibition of DNA binding by MgrA, a global virulence regulator. Two previously uncharacterized thioredoxin-like proteins, denoted TrxP and TrxQ, are S-sulfhydrated in sulfide-stressed cells and are capable of reducing protein hydrodisulfides, suggesting that this PTM is potentially regulatory in S. aureus. In conclusion, our results reveal that S. aureus harbors a pool of proteome- and metabolite-derived RSS capable of impacting protein activities and gene regulation and that H2S signaling can be sensed by global regulators to affect the expression of virulence factors.

Bacterial Pathogens Hijack the Innate Immune Response by Activation of the Reverse Transsulfuration Pathway

“…Although we found that H 2 S does not affect H. pylori growth, it has been described that H 2 S can signal in bacteria such as Staphylococcus aureus through S-sulfhydration (16). This mechanism, which can be potentiated by the gasotransmitter NO, results in the regulation of protein activities, an increase of the antioxidant capacity, and virulence gene expression (16,46). Consequently, the effect of macrophage CTH-derived H 2 S on H. pylori gene expression deserves further investigation.…”

“…Epithelial and immune cells of the gastrointestinal tract can produce hydrogen sulfide (H 2 S), the third gaseous signaling molecule associated with physiological properties (11), including vasorelaxation (12), neuroprotection (13), oxidant regulation (14), and anti-inflammatory action (15). In addition, H 2 S has been shown to signal in pathogenic bacteria (16). H 2 S is synthesized in biological milieus by three enzymes, namely, cystathionine ␤-synthase (CBS), cystathionine ␥-lyase (CTH), and mercaptopyruvate sulfurtransferase (MPST).…”

Hydrogen sulfide in physiology and pathogenesis of bacteria and viruses

“…Several key host transcription factors, Nrf2 and Nf‐κB, are directly targeted by H 2 S via S‐persulfidation . Apart from eukaryotic systems, a recent study, for the first time, assessed widespread S‐persulfidation of proteins in Staphylococcus aureus ( S. aureus ) . More importantly, H 2 S exposure increased the level of S‐persulfidation, whereas mutations in transsulfuration pathways ( cysM and metB ) had an opposite effect .…”

OxyR senses reactive sulfane sulfur and activates genes for its removal in Escherichia coli

“…A reasonable hypothesis is that they use glutathione (GSH) or NADPH to reduce sulfane sulfur to H 2 S and then release it out of cells (Carbonero et al, 2012) , as observed in anaerobically cultured fungi (Abe et al, 2007; Sato et al, 2011) . A recent report that two thioredoxin-like proteins catalyze the reduction of protein persulfidation in Staphylococcus aureus also support the hypothesis (Peng et al, 2017) . However, it is unclear whether sulfane sulfur induces the expression of these enzymes.…”

“…As nucleophiles, they are better reductants than thiols (Ida et al, 2014) ; as electrophiles, the electrophilic sulfane sulfur (S 0 ) can be transferred to protein thiols to generate protein-SSH, which modifies enzyme activities and protects proteins from irreversible oxidation (Mustafa et al, 2009; Paul & Snyder, 2015) . Owing to these unique dual-reactivities, reactive sulfane sulfur is involved in many cellular processes, such as redox homeostasis maintenance, virulence regulation in pathogenic bacteria, and biogenesis of mitochondria (Fujii et al, 2018; Peng et al, 2017) . Albeit the good roles, sulfane sulfur may be toxic at high concentrations.…”