Hypoxia-induced phenotypic transformation of scleral fibroblasts promotes activation of the adhesion patch pathway through paracrine effects leading to choroidal damage

Myopia has become an important cause of vision loss, where its prevalence is increasing in the younger population. The pathogenesis of myopia remains poorly understood. In this study, human scleral fibroblasts (HSFs) were induced by hypoxia to verify the effects of hypoxia on the phenotypic transformation and extracellular matrix remodeling of HSFs. Subsequently, exosomes of HSFs under normoxic and hypoxic conditions were extracted and validated to explore the effects of HSFs on human choroidal endothelial cells (HCEC). Transcriptome sequencing analyzed the possible molecular mechanisms by which HSFs affect HCEC. The results showed that hypoxia resulted in reduced proliferative capacity of HSFs, promoted cellular fibrosis as well as aggravated oxidative damage. The HCEC group treated with hypoxia-induced HSFs conditioned medium or exosomes exhibited significantly more cellular damage compared to the normal conditioned group. Transcriptome sequencing showed that differentially expressed genes in hypoxia-induced HSFs-derived exosome-treated HCEC were significantly enriched in the Focal adhesion signaling pathway. This sequencing result was verified by RT-qPCR and Western blot experiments. Our study demonstrated in vitro that hypoxia induces phenotypic transformation of HSFs, and that lead to HCEC damage through a paracrine mechanism, a process that may be mediated by the adhesion patch signaling pathway.