Characterization and proteome profiling of extracellular vesicles in a murine model of Staphylococcus aureus endophthalmitis

Endophthalmitis is a vision-threatening complication of intraocular surgery or penetrating injury of which Staphylococcus aureus is an important etiological agent. Extracellular vesicles (EVs) hold a tremendous possibility for developing diagnostic and therapeutic biomarkers due to their role in the pathogenesis of various infections. The aim of this study was to characterise the protein cargo of EVs, isolated from a murine (C57BL/6) model of S. aureus endophthalmitis by LC-MS/MS. Contralateral eye injected with sterile media served as control and both eyes were enucleated after 24 h, followed by extraction of EVs by ultracentrifugation. EVs were characterized by DLS and western blotting with tet-raspanin markers, CD9 and CD81 and quantified by ExoCet quantification kit. Proteomic analysis iden-tified 1964 proteins (FDR <= 0.01) in EVs from infected mice eyes, of which 40 proteins varied significantly in their amounts in comparison to EVs obtained from control eyeballs (P-value <= 0.05). The results of this study provide insight into the global EV proteome of S. aureus endophthalmitis with their functional correlation and differential protein amounts between infected and control set. Annexin A5, cathepsin D and C5a play a pivotal role in disease pathogenesis and could possibly play a role as a prognostic marker in endophthalmitis. (C) 2022 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Automated summary

In this study, the protein cargo of extracellular vesicles (EVs) in Staphylococcus aureus endophthalmitis was characterized using a mouse model. The researchers identified significant differences in the amounts of certain proteins between the infected and control groups. Annexin A5, cathepsin D, and C5a play important roles in the pathogenesis of endophthalmitis and may serve as prognostic markers.