Proteomic Analyses of Early Versus Advanced Primary Open-Angle Glaucoma Uncover Biochemical Signatures Associated With Disease Staging

Primary open-angle glaucoma (POAG) is a leading cause of blindness, yet the biochemical mechanisms underlying disease progression remain poorly understood. This study characterized aqueous humor (AH) across early and advanced stages of POAG using large-scale proteomics. AH samples were collected from patients with mild POAG, advanced POAG, and non-glaucomatous controls in this prospective cross-sectional study. Profiling of 8000 proteins was performed using an antibody array. Hierarchical clustering, principal component analysis (PCA), Gene Ontology (GO), and pathway enrichment analyses were performed to identify differentially expressed proteins, biological processes, and molecular functions associated with disease stages. Top differential proteins were also correlated with key clinical parameters. Proteomic signatures demonstrated distinct clustering between control and glaucoma patients, with progressive shifts from mild to advanced stages. Comparisons between control and each glaucoma group revealed significant enrichment in pathways related to wound healing, extracellular matrix (ECM) remodeling, and immune responses. Notably, distinct proinflammatory and immune proteins and pathways were enriched when comparing mild to advanced POAG stages. Finally, the top differential AH proteins correlated with multiple clinical endpoints, including intraocular pressure and a variety of retinal outcomes. This signature revealed a tight network associated with disease stage, oriented on immune cell migration and function, and identifying soluble TRPC6 as a novel biomarker. To our knowledge this is the first study to compare large scale proteomic analysis of AH from patients with POAG across disease stages, suggesting new mechanisms underlying glaucoma progression.