Exosomal CD73 from endometrial regenerative cells confers protective effects against ischemia-reperfusion injury in kidney transplantation

Renal ischemia-reperfusion injury (IRI) compromises transplantation outcomes, with macrophages acting as key regulators of the underlying pathophysiology. The adenosinergic signaling pathway plays a pivotal role in modulating macrophage phenotypes during ischemia. CD73, the key enzyme driving adenosine generation, is highly enriched in exosomes derived from endometrial regenerative cells (ERC-Exo). In this study, we investigated whether CD73-expressing ERC-Exo could attenuate renal IRI following kidney transplantation. Syngeneic renal transplantation was performed in C57BL/6 mice, with grafts subjected to 3 h of cold ischemia. Successfully transplanted mice were randomized into three groups: untreated, ERC-Exo-treated, and CD73^-/-ERC-Exo-treated. Histological analysis confirmed that the transplant-induced IRI model exhibited consistent hallmarks of renal injury, including tubular necrosis and shedding. CD73-expressing ERC-Exo markedly attenuated renal dysfunction and structural damage, accompanied by a reduction in M1 macrophages and an enrichment of the M2 phenotype. Parallel in vitro experiments revealed that ERC-Exo suppressed Lipopolysaccharide-induced M1 polarization and promoted M2 differentiation in bone marrow-derived macrophages. Furthermore, CD73-expressing ERC-Exo enhanced macrophage-mediated induction of regulatory T cell (Treg) differentiation, increased their phagocytic capacity, and modulated cytokine secretion profiles. Notably, the therapeutic efficacy of ERC-Exo was abolished following CD73 knockout or A2A receptor antagonism, which was mechanistically associated with alterations in the AMPK/SIRT1/NFκB axis. These findings demonstrated that CD73-expressing ERC-Exo serve to harness the adenosinergic pathway to regulate macrophage polarization. By restoring macrophage-mediated immune homeostasis, ERC-Exo represents a promising bio-derived nanotherapeutic strategy for improving kidney transplantation outcomes.