Proteomic profiling of extracellular vesicles derived from ARPE-19 cells challenged with Aspergillus flavus and Candida albicans: application in fungal endophthalmitis.

Extracellular vesicles (EVs) are nano-sized-particles that play an important role in cellular cross-talk. The aim of this study was to understand the proteomic cargo of EVs, released by Retinal Pigment Epithelial (RPE) cells challenged with Candida albicans (C-CA) and Aspergillus flavus (C-AF). EVs were isolated from culture supernatant of retinal cells infected with fungal pathogens and characterized by dynamic light scattering, SEM, and western blot. EV proteome was then evaluated by mass spectrometry (LC-MS/MS). Isolated EVs were approximately 120-150 nm and higher in number in infected group compared to control. Proteomic profiling of EVs from infected cells, showed a total of 419 and 254 differentially expressed proteins, of which 218 were upregulated in C-CA group and 81 proteins were upregulated in C-AF group. Gene ontology revealed majority of proteins associated with transport, cell migration, and in activation of innate immune response. Proteins identified were annexins, calpain, and Sorcin proteins. Additionally, KEGG analysis unveiled involvement of MAPK, HIF-1, and PI3K-AKT signalling pathways. Proteomic results indicate that EVs cargo derived from fungal-infected retinal cells can activate immune signalling pathways and might contribute to the pathogenesis of endophthalmitis, indicating the potential use of EVs as theranostic marker for management of fungal infections.