Exosomes derived from hucMSC attenuate renal fibrosis through CK1δ/β-TRCP-mediated YAP degradation

Exosomes from human umbilical cord mesenchymal stem cells (hucMSC-Ex) have been suggested as novel nanomaterials for regenerative medicine. Here we explored the roles of hucMSC-Ex through regulating Yes-associated protein (YAP) in renal injury repair by using rat unilateral ureteral obstruction (UUO) models. Our study identified mechanical stress induced YAP nucleus expression and stimulated collagen deposition and interstitial fibrosis in the kidney. Then, infusion with hucMSC-Ex promoted YAP nuclear cytoplasmic shuttling and ameliorated renal fibrosis in UUO model. Interestingly, hucMSC-Ex delivered casein kinase 1δ (CK1δ) and E3 ubiquitin ligase β-TRCP to boost YAP ubiquitination and degradation. Knockdown of CK1δ and β-TRCP in hucMSC decreased the repairing effects of hucMSC-Ex on renal fibrosis. Our results suggest that hucMSC-Ex attenuates renal fibrosis through CK1δ/β-TRCP inhibited YAP activity, unveiling a new mechanism for the therapeutic effects of hucMSC-Ex on tissue injury and offering a potential approach for renal fibrosis treatment.