Comparative gene expression analysis of ex vivo isolated myeloid-derived suppressor cells (MDSCs) derived from rapamycin and PBS-treated mice

The macrolide rapamycin is known for its immunosuppressive properties since it inhibits mTOR (mammalian target of rapamycin), which activity affects differentiation and functions of various innate and adaptive immune cells involved in graft-versus-host disease development. Since rapamycin procures immunosuppressive effects on the immune response, rapamycin is an attractive candidate for graft-versus-host disease prevention after allogeneic bone marrow transplantation. Recently, an activating effect of rapamycin on the function of myeloid-derived suppressor cells (MDSCs), a subset of immune suppressive cells of myeloid origin was reported. However, the effect of rapamycin treatment on MDSCs induction and function in the management of graft-versus-host disease is largely unknown. We used an MHC class I and II mismatched parent into F1 bone marrow transplantation mouse model to elucidate the mechanisms of rapamycin on MDSCs in the context of graft-versus-host disease prevention. To define the impact of rapamycin therapy on MDSCs gene expression profile, we performed mircoarray analysis and compared gene expression profiles of ex vivo isolated MDSCs from rapamycin and PBS treated mice Splenic MDSCs were isolated 10 days after bone marrow transplantation for RNA extraction and hybridization on a affymetrix microarray. We analyzed 3 mice each group.