Exosomes: Potential executors of IL‐35 gene‐modified adipose‐derived mesenchymal stem cells in inhibiting acute rejection after heart transplantation
Hao Guo, Baozhu Li, Nan Li, Xin Liu, Haopeng Gao, Xuan Sun, Na Zhao
Abstract
Abstract Heart transplantation has become the only 'cure' for end‐stage heart diseases, but acute allograft rejection is the major obstacle to the survival of patients. Our previous studies showed that IL‐35 gene‐modified adipose‐derived mesenchymal stem cells (IL‐35‐ASCs) can effectively inhibit graft rejection and prolong the survival of transplanted hearts in mice. This study further explored the mechanism of IL‐35‐ASCs, especially focusing on the important role of IL‐35‐ASC‐derived exosomes (IL‐35‐ASCexos) in inhibiting acute rejection. IL‐35‐ASCs were constructed in vitro and pretreated with IL‐35 neutralizing antibody and GW4869 (an inhibitor of neutral sphingomyelinase that impairs exosome biogenesis/release). Then, pretreated IL‐35‐ASCs and CD4 + T cells were cocultured in Transwell plates, and changes in regulatory T cells (Tregs) and cytokines were detected. Then, IL‐35‐ASCexos were extracted, identified and analysed, and their immunoregulatory effects on CD4 + T cells were studied through coculture experiments. Finally, IL‐35‐ASCexos were applied to a mouse heart transplantation model to investigate the therapeutic effects on acute rejection of the allograft. The coculture experiment showed that the IL‐35‐neutralizing antibody could not completely block the immunosuppressive function of IL‐35‐ASCs, while GW4869 could effectively reduce their immunoregulatory characteristics. Similar to IL‐35‐ASCs, IL‐35‐ASCexos also have powerful immunosuppressive properties, effectively upregulating the Treg ratio in vivo and in vitro and prolonging graft survival. As the main effectors of IL‐35‐ASCs, these findings highlight the therapeutic potential of IL‐35‐ASCexos in inhibiting acute cardiac rejection of the allograft. Although the specific mechanism remains unclear and needs to be further explored, IL‐35‐ASCexos therapy is expected to become a new method to inhibit acute graft rejection.