Abstract
PURPOSE: Pseudoexfoliation (PEX) glaucoma is caused by progressive accumulation of abnormal fibrillar aggregates in aqueous humor outflow tissues. The current lack of effective models for PEX research, replicating the key feature of PEX material production, represents a critical gap in understanding the molecular pathomechanisms and identifying specific therapeutic targets. We have developed an advanced in vitro model using stromal fibroblasts from iridectomy specimens of PEX glaucoma patients with an appropriate genetic background. METHODS: Peripheral iridectomy specimens were obtained from patients with PEX glaucoma (n = 35) during routine trabeculectomy. Stromal fibroblasts were enriched from heterogenous cell cultures. Extracellular matrix formation was stimulated and modulated in two- and three-dimensional (3D) spheroid cultures by TGF-β1, Ficoll 400, all-trans-retinoic acid (ATRA), and curcumin. Cell cultures were analyzed by immunocytochemistry, transmission electron microscopy and qPCR. Immortalized cell lines (n = 4) were generated by SV40 large T-antigen transfection. RESULTS: Fibroblasts carrying the high-risk haplotype of LOXL1 (lysyl oxidase-like 1) expressed PEX-relevant matrix components and assembled an elastic fibrillar network, particularly upon treatment with TGF-β1 and the macromolecular crowding agent Ficoll 400. In 3D spheroid cultures, the presence of typical fibrillar PEX aggregates could be demonstrated by electron microscopy. Matrix production could be effectively suppressed by ATRA and curcumin. Similar to primary cells, immortalized cell lines formed 3D spheroids and expressed PEX-relevant matrix components including typical fibrillar aggregates. CONCLUSIONS: This advanced in vitro model, which recapitulates the hallmark of PEX syndrome/glaucoma, may provide a useful, easy-to-handle platform for studying disease mechanisms, assessing the impact of genetic and external factors, and exploring effects of targeted therapies for PEX-associated fibrosis.