Universal Corneal Epithelial-Like Cells Derived from Human Embryonic Stem Cells for Cellularization of a Corneal Scaffold

PURPOSE: We generated universal corneal epithelial cells (CEC) from human embryonic stem cells (hESC) by genetically removing human leukocyte antigens (HLA) class I from the cell surface. METHODS: The serum-free, growth factor-free, and defined medium E6 was used to differentiate hESC to CEC. Decellularized murine corneas were recellularized with hESC-derived CEC. Using CRISPR/Cas9, β-2-microglobulin (B2M) was deleted in hESC to block the assembly of HLA class-I antigens on the cell surface to generate B2M(−/−) CEC. RESULTS: E6 alone was sufficient to allow hESC differentiation to CEC. A time-course analysis of the global gene expression of the differentiating cells indicates that the differentiation closely resembles the corneal development in vivo. The hESC-CEC were highly proliferative, and could form multilayer epithelium in decellularized murine cornea, retain its transparency, and form intact tight junctions on its surface. As reported before, B2M knockout led to the absence of HLA class-I on the cell surface of hESC and subsequently derived CEC following stimulation with inflammatory factors. Moreover, B2M(−/−) CEC, following transplantation into mouse eyes, caused less T-cell infiltration in the limbal region of the eye than the wild-type control. CONCLUSIONS: CEC can be derived from hESC via a novel and simple protocol free of any proteins, hESC-CEC seeded on decellularized animal cornea form tight junctions and allow light transmittance, and B2M(−/−) CEC are hypoimmunogenic both in vitro and in vivo. TRANSLATIONAL RELEVANCE: B2M(−/−) hESC-CEC can be an unlimited and universal therapy for corneal repair in patients of any HLA type.