Proteomic profiling of exosomes in a mouse model of Candida albicans endophthalmitis

Exosomes play pivotal roles in intercellular communication, and pathophysiological functions. In this study, we aimed to understand the role of exosomal proteome derived from C. albicans infected mice (C57BL/6) eyeball. Exosomes were characterized by Dynamic Light Scattering and Western blot, quantified and subjected to LC-MS/ MS and cytokine quantification by ELISA. The average size of exosomes was 170-200 nm with number of exosomes amounted to 1.42 x 1010 in infected set compared to control (1.24 x 109). Western blot was positive for CD9, CD63 and CD81 confirming the presence of exosomes. IL-6, IL1 beta, TNF-alpha, and IFN-gamma levels were significantly elevated in infected eye at 72 h.p.i. Proteomic analysis identified 42 differentially expressed proteins, of these 37 were upregulated and 5 were downregulated. Gene Ontology (GO) revealed enrichment of cell adhesion, cytoskeleton organisation, and cellular response proteins such as aquaporin-5, gasdermin-A, CD5 antigen-like, Catenin, V-ATPase, and vesicle associated protein. Additionally, KEGG pathway analysis indicated the association of metabolic and carbon signalling pathways with exosomes from C. albicans infected eye. The protein cargo in exosomes released during endophthalmitis with C. albicans seems to play a unique role in the pathogenesis of the disease and further validations with larger cohort of patients is required to confirm them as biomarkers.