GM-CSF-mediated inducement of bone marrow MDSCs by TSA and effect on survival of graft in mice

Abstract

ObjectiveThis study analyzed the effect of HDAC inhibitor, trichostatin A (TSA), in inducing granulocyte–macrophage colony-stimulating factor (GM-CSF)-mediated bone marrow (BM) cell differentiation to myeloid-derived suppressor cells (MDSCs) in vitro and in vivo.MethodsBM cell differentiation to CD11b + GR-1 + MDSCs was achieved by in vitro culture with TSA and GM-CSF, and the collected cells were analyzed by mixed lymphocyte culture to identify suppressive actions against effector T cells. RT-PCR and ELISA were conducted to analyze the CCL5 mRNA and protein levels in TSA + GM-CSF + BM, GR-1 + MDSCs and GR-1 + MDSC + CCL5 groups. The survival of cardiac grafts was compared between groups.ResultsTSA was beneficial for the GM-CSF-mediated BM differentiation to CD11b + GR-1 + MDSCs. Adoptive transfer of GR-1 + MDSCs was powerful in suppressing CD4 + CD25-T cell proliferation and the effect was mediated by iNOS and HO-1; it also increased CCL5 gradient concentration between grafts and plasma to recruit Treg to grafts and prolong the survival of the grafts. Survival analysis revealed that the survival of grafts after adoptive transfer of GR-1 + MDSCs could be prolonged.ConclusionThis study helps in further research on the application value of MDSCs in the field of transplant, and may provide a new thought for the cell therapy in inducing immune tolerance in organ transplant.