Temperature influences the composition and cytotoxicity of extracellular vesicles in Staphylococcus aureus

Staphylococcus aureus is a pathogenic bacterium but also a commensal of skin and anterior nares in humans. As S. aureus transits from skins/nares to inside the human body, it experiences changes in temperature. The production and content of S. aureus extracellular vesicles (EV) have been increasingly studied over the past few years and EVs are increasingly being recognized as important to the infectious process. Nonetheless, the impact of temperature variation on S. aureus EVs has not been studied in detail as most reports that investigate EV cargoes and host cell interactions are performed using vesicles produced at 37°C. Here we report that S. aureus vesicle production is temperature-dependent with greater vesiculation at 40°C. We demonstrate that the temperature dependent regulation of vesicle production in S. aureus is mediated by the alpha phenol soluble modulin peptides (aPSMs). Through proteomic analysis, we observed increased packaging of virulence factors at 40°C whereas more total proteins are present in EVs produced at 34°C. Similar to the protein content, we perform transcriptomic analysis and demonstrate that the RNA cargo is impacted by temperature also. Finally, we demonstrate greater aPSM- and a-toxin mediated erythrocyte lysis with 40°C EVs but 34°C EVs are more cytotoxic toward THP-1 cells. Together our study demonstrates that small temperature variations have great impact on EV biogenesis and shape the interaction with host cells. Overall design: Six data sets in total. Three biological replicates of Extracellular vesicles produced from S. aureus grown at each three temperatures used in the study i.e 34 C, 37 C