ABSTRACT: Background: Age-related macular degeneration (AMD) is the leading cause of blindness worldwide, predominantly affecting individuals over 60. AMD is classified into two clinical forms: dry (DAMD) and neovascular (NAMD). NAMD, characterized by choroidal neovascularization and increased vascular endothelial growth factor (VEGF) levels, is treated with anti-VEGF therapy, the gold standard for preventing vision loss. However, challenges including non-response to treatment, persistent disease activity, and unnecessary anti-VEGF administration necessitate the identification of predictive biomarkers to optimize therapy. Exosomes (exo) are extracellular vesicles known for their stability and role in cellular communication, carrying diverse molecular contents, including RNA. Although the role of exo-RNA in AMD pathogenesis is well known, their role in the response to anti-VEGF treatment has not yet been investigated. Current study aim to investigate the role of exo-RNAs as potential biomarkers for predicting anti-VEGF treatment response in NAMD patients. Methods: Plasma-derived exo-RNA were analyzed pre- and post-treatment to identify predictive biomarkers from 41 NAMD patients treated with intravitreal bevacizumab. Exo were isolated using exoRNAeasy midi kit and characterized by TEM, NTA, and Western blot. Then, RNA-seq was performed to profile exo-RNAs and key candidates were validated using RT-qPCR. Results: Following anti-VEGF therapy, 68.3% of NAMD patients (mean age: 70.8 ± 6.14), demonstrated anatomical success, while 53.7% achieved functional success. Based on RNA-seq comparative analysis between the two groups revealed that translation mechanisms were significantly regulated, particularly within the context of upregulated pathways. Genes associated with molecular functions such as insulin response, transport, angiogenesis, and oxygen transport were prominently implicated. Conversely, the evaluation of downregulated pathways indicated substantial alterations in RNA catabolic processes and the regulation of gene expression. RNA-seq revealed BMP6 and STK39 as key candidate genes, with post-treatment dysregulation in hsa-miR-4692 expression, a microRNA targeting STK39. Finally, RT-qPCR validation show that elevated pre-treatment exo-STK39 levels were significantly associated with anatomical success (*p=0.04).
