3D mesenchymal stem cell exosome-functionalized hydrogels for corneal wound healing

Mesenchymal stem cell (MSC)-derived exosomes have the potential to sustain immune homeostasis and facilitate tissue regeneration , and those effects can be potentiated under three-dimensional (3D) cell culture conditions. Nevertheless, whether exosomes derived from 3D-cultured MSCs (3D-Exos) exert therapeutic effects on the injured corneas and the underlying mechanism remain unclear. In this study, MSCs are cultured in a gelatin methacryloyl (GelMA) hydrogel to produce 3D-Exos. In vitro experiments revealed that the 3D-cultured MSCs maintained their stemness, the exosomes were produced in better yield, and the generated 3D-Exos possess exceptional anti-inflammatory, pro-proliferative and tissue remodeling properties. Moreover, the 3D-Exos that were delivered by the GelMA hydrogel displayed a sustained release profile for multi-dimensional injured cornea repair. Extensive in vitro studies further demonstrated that, compared with the two-dimensional (2D)-Exo-hydrogel treatment, 3D-Exo-hydrogel treatment yielded better recovery of corneal morphology and function, as revealed by mitigated inflammation, promoted corneal epithelium and limbus repair, and reduced scar formation in the stroma . Mechanistically, the 3D-Exos promoted the proliferation of cornea-derived cells and reduced the release of inflammatory factors via miR-150-5p targeting of the PDCD4 gene. Overall, the developed 3D-Exo-hydrogel sustained release system may represent a promising cell-free strategy for the treatment of various corneal diseases . • Three-dimensional (3D)-cultured mesenchymal stem cells (MSCs) maintain their stemness and have improved exosome yields. • The 3D-Exo-gelatin methacryloyl (GelMA) hydrogel sustained release system accelerates the healing of corneal wounds. • 3D-Exos exert anti-inflammatory, pro-proliferative and tissue remodeling effects via miR-150-5p targeting of the PDCD4 gene. • A promising cell-free regenerative therapy was developed for the treatment of various corneal diseases and injuries.