CD73-expressing endometrial regenerative cell-derived exosomes mitigate acute cardiac allograft rejection through regulating adenosine metabolism in mice.

backgroundOrgan transplantation is a life-saving option for end-stage organ dysfunction, but long-term graft survival is limited by unavoidable allograft rejection. While endometrial regenerative cells (ERCs) have been shown to alleviate acute rejection, the underlying mechanisms are not fully understood. This study explored whether ERC-derived exosomes contribute to this effect through CD73-mediated immunoregulation.

methodsERCs were pretreated with GW4869, an exosome inhibitor, to block exosome secretion, and CRISPR-Cas9-based CD73 knockout was performed to validate the role of CD73 in the ERC and ERC-exos. CD73 enzyme activity was measured using an AMP assay in vitro, whereas ATP, AMP, and adenosine levels were quantified using mass spectrometry in vivo. A murine allogeneic heart transplantation model (BALB/c to C57BL/6) was established to evaluate the immunoregulatory effects of ERC-exos in vivo. Graft tissues were analyzed by H&E staining, and immunohistochemistry and flow cytometry analysis of the spleens were performed to assess graft rejection. In vitro, flow cytometry was used to examine CD4

resultsGW4869 reduces the ability of ERCs to inhibit CD4

conclusionCD73 expression is crucial for the ability of ERC-exos to generate adenosine to mitigate acute cardiac allograft rejection in mice. ERC-exos combined with rapamycin can prolong allograft survival.