Melatonin-inspired hybrid spheroids accelerate intestinal repair via YAP-driven fetal reprogramming

Following injury, prostaglandin E₂ (PGE₂) drives intestinal epithelial repair by inducing revival stem cells (RSCs), which compensate for the loss of homeostatic Lgr5⁺ stem cells. Using intestinal organoid models, we demonstrate that melatonin potentiates the PGE₂- or damage-induced RSC emergence by rewiring cellular plasticity toward a fetal-like state and sustaining pro-regenerative YAP activity, thereby enhancing overall repair capacity. To translate this finding into a therapeutic application, we developed a biohybrid heterospheroid (Mel-HS) by combining melatonin-loaded poly(lactic-co-glycolic acid) microspheres with 3D-cultured mesenchymal stem cells (MSCs), which serve as a PGE₂ source. We confirmed that this biohybrid construct preserves the paracrine capacity of MSCs to secrete PGE₂. Notably, Mel-HS demonstrates superior in vivo retention compared with naive 3D-MSCs, underscoring the cytoprotective effect of encapsulated melatonin in enhancing MSC viability. Furthermore, Mel-HS promoted robust RSC induction while simultaneously providing protection against inflammatory- and oxidative insults in vitro. In a colitis model, Mel-HS accelerated mucosal healing through the dual mechanisms-immunomodulation and enhanced RSC-driven repair-resulting in marked clinical improvement. Collectively, our findings highlight the therapeutic potential of enhancing endogenous regeneration with melatonin and MSCs, establishing a promising framework for next-generation biohybrid cell therapeutics in inflammatory bowel disease management.