Galectin-9 Mediates The Effect Of Endometrial Regenerative Cell On The Induction Of Long-term Cardiac Allograft Survival

BackgroundOrgan transplantation is an effective treatment for tumors,congenital malformations and end-stage organ failure.With the application of immunosuppressive agents,the incidence of acute rejection is significantly reduced,but the continued and recurrent chronic rejection still limits the graft long-term survival.Meanwhile,the side effects of immunosuppressant are inevitable,such as liver and kidney injury,bone marrow suppression,infection and tumorigenesis.Therefore,it is very important to explore novel immunomodulatory strategies.Mesenchymal Stem Cell(MSC)has the ability of self-renewal,multiple differentiation,directional migration and immune regulation,and has become one of the important candidates for cellular immunotherapy,but applying MSC in clinic still has certain limitations.When compared with MSC,the application of Endometrial Regenerative Cell(ERC)has unique advantages,such as:unlimited sources,non-invasive collection method,body waste reuse,and easy to replication.However,the research on the immunomodulatory mechanism of ERC is still not comprehensive.Galectin-9(Gal-9)has been reported to be involved in a variety of physiological and pathological processes,such as apoptosis,inflammation,cell adhesion and tumor escape.At present,a few studies have demonstrated that Gal-9 is expressed on the surface of MSC in vitro,but there are few reports focusing on the immunoregulatory effects of Gal-9 in ERC cells.The research of Gal-9-mediated ERC therapy,especially in transplantation model,still need to be elucidated.ObjectsThe purpose of this study is to investigate the expression of Gal-9 on ERC,and to explore Gal-9-mediated ERC effect on the regulation of the number and function of activated lymphocytes in vitro,as well as the effect on graft survival and immune microenvironment in vivo.MethodsThis study is divided into three parts.PartⅠ:Menstrual-derived ERC cells were isolated and cultured,and their phenotypes were identified.The expression of Gal-9in ERC cells was evaluated.PartⅡ:Gal-9-ERC(ERC with Gal-9 high-expression)were harvested,and their effects on the regulation of number and function of activated lymphocytes were evaluated.PartⅢ:Gal-9-ERC and Gal-9-ERC+Rapamycin(Rapa)were implemented separately to explore their effects on the regulation of immune microenvironment,as well as the graft survival time.ResultsERC were successfully isolated and cultured,and IFN-γpriming significantly increased Gal-9 m RNA and protein expression in ERCs.In vitro,it was found that Gal-9 is involved in mediating ERC therapy in inhibiting the proliferation of CD4~+,CD8~+,Th1,Th17 and antigen-presenting B cells,promoting the proliferation of Tregs,intervening in the secretion of IgG and IgM antibodies,and reducing the expression of inflammatory factors.In vivo,it was found that Gal-9 is involved in mediating ERC regulation in reducing lymphocyte infiltration and inflammatory factor expression,alleviating rejection and pathological damage,prolonging allograft survival time,inhibiting CD4~+T,CD8~+T,Th1 and Th17 cell activation and proliferation,promoting the proliferation of Tregs,and reducing the expression of circulating anti-donor specific antibodies(IgG and IgM).In addition,given the generated results,it also suggests that Gal-9-ERC+Rapamycin combination therapy has a synergistic role,and possesses the best therapeutic effect.ConclusionERC expresses Gal-9,which is involved in the regulation of lymphocyte numbers and functions.Gal-9-ERC+Rapamycin combination therapy has a synergistic role in preventing immune rejection and promoting long-term cardiac allograft survival.