Extracellular Matrix Proteome of Human Corneas

BACKGROUND/OBJECTIVES: The cornea, the transparent outer layer of the eye, is avascular and composed of three layers: a self-renewing epithelium, a transparent stroma rich in extracellular matrix (ECM) and an endothelium. This study aimed to profile ECM proteins including proteoglycans, from human decellularized extracellular matrix (hdECM) proteins using proteomics analysis. SUBJECTS/METHODS: Three independent batches of lyophilised hdECM samples were subjected to proteomics analysis. Samples were processed by in-gel trypsin digestion and analysed on a Q- Exactive mass spectrometer. Protein identification and label free quantification were performed using Proteome Discoverer 2.2.0.388. RESULTS: Proteomic profiling identified an average of 18 proteins per batch, with 13 consistently present across all samples. Key proteins, TGF-β, keratocan, fibrillin and collagen XII, were abundant, highlighting their role in inflammation regulation, collagen organisation, and matrix remodelling. Proteoglycans such as docorins and lumican were also detected indicating their contribution to ECM structure and maintenance of corneal transparency. Network and Pathway analysis revealed involvement in ECM organization, integrin interactions, glycosaminoglycan metabolism, and collagen fibril assembly. These proteins are critical for preserving corneal architecture, modulating cell behaviour, and supporting processed such as signalling, migration, angiogenesis, and tissue repair particularly through proper collagen spacing essential for corneal transparency. This study, to the best of our knowledge, represents the first comprehensive profiling of extracellular matrix proteins from decellularised human corneas.