Proteomic profiling of aqueous humor-derived exosomes in Vogt-Koyanagi-Harada disease and Behcet's uveitis.

Vogt-Koyanagi-Harada (VKH) disease and Behcet's uveitis (BU) are the two major vision-threatening uveitis entities. This study performed the first label-free quantitative proteomics on aqueous humor-derived exosomes from 84 patients with VKH or BU to determine their potential roles. Sixty-five differentially expressed proteins (DEPs) and 40 DEPs were detected in the VKH and BU groups, respectively. GO and KEGG analysis showed that DEPs were mainly enriched in the complement-related pathways. The complement C1q subcomponent subunit B (C1QB) was identified as a key exosomal protein, and its expression was significantly increased by western blotting in both diseases. Additionally, the integrated analysis based on the published scRNA-seq data showed that C1QB-containing exosomes were mainly produced by mononuclear macrophages in the anterior segment tissue. Overall, our proteomic profiling highlights that complement-related pathways may be actively involved in the pathogenesis of these two diseases. These pathways may also serve as treatment targets for both diseases.