The Mechanism Of MicroRNA-155 In Heart Transplantation

Part ?Establishment of Heart Transplantation in Mice and Changes of the miR-155 Expression in Graft-infiltrating Lymphocytes.Objective:To established the stable model of heart transplantation and definite the changes of miR-155 expression in graft-infiltration lymphocytes.Methods:1:C57BL/6 male mice served as recipients, and BALB/c male mice served as doners for established the model of acute cardiac rejection; or Bm12 mice served as doners for established the model of chronic cardiac rejection. The mean survival time of cardiac allografts were evaluated.2:7 days after heart transplantation in acute rejecton or 60 days in chronic rejection, the degree of cardiac grafts were analyzed by HE.3:Isolate the graft-infiltraton lymphocytes, miR-155 were selected for qPCR analysis.Results:1:The mean survive time were (7.5 ± 0.37)/(63.4± 4.37) days separately in acute/chronic rejection of heart transplantation.2:Compared to isograft group, others showed the inflammatory cell infiltration, with the obvious myocardial necrosis and fibrosis.3:miR-155 was obviously upregulated among infiltrating lymphocytes of the heart allograftsConclusion:We established the stable model of heart transplantation and could be used for further researches. And miR-155 might play a important role in lymphocyte-related cardiac rejectonPart ?The Role of miR-155 in Acute Cardiac RejectionObjective:To explored the roles of miR155 in acute cardiac rejecionMethod:A model of heterotopic murine heart transplantation (Bm12 to miR-155+/+or miR-155-/- mice) was performed and allograft survival, histology, mRNA expression were analyzed. The proportion of T-cell subpopulations in spleens and infiltrating cells in allografts were analyzed by flow cytometry. The accelerated experiments were performed by tail intravenous injection of either rIL-17A or PBS after heart transplantation. In adoptive transfer experiment, miR155-/- and/or miR155+/+ CD4+splenocytes is injected into Rag1-/- mice and cardiac transplantation were performed after 24 hours.Results:miR-155-/- mice were resistant to cardiac rejection along with the weaken T cell-mediated inflammation, especially in Th17, and developed less severe cardiac injury. rIL17A could restore this relieved injury. And Adoptive transfer further verified that miR155 drives the Th17 immune response by CD4+T cell. The competitive experiments implied that miR155 play a vital role in the stability of the Th17 phenotype.Conclusion:miR-155 regulates Th17-related inflammation in acute cardiac rejecton.Part?The Role of miR-155 in Chronic Cardiac RejectionObjective:To explored the roles of miRl 55 in chronic cardiac rejecionMethod:A model of heterotopic murine heart transplantation (BALB/c to miR-155+/+or MiR-155-/-mice) was performed and allograft survival, histology, mRNA expression were analyzed. The proportion of T-cell subpopulations in spleens and infiltrating cells in allografts were analyzed by flow cytometry. The accelerated experiments were performed by tail intravenous injection of either rIL-17A or PBS after heart transplantation. In vitro, the differentiation of Thl/Th17/Treg in miR-155+/+ or miR-155-/- mice were investigated. And the Th-related targets of miR-155 were also determined.Results:miR-155-/- mice were resistant to cardiac allograft vasculopathy along with the weaken T cell-mediated inflammation, especially in Th17, and developed less severe cardiac injury. rIL17A could restore this relieved injury. We also demonstrated that miR-155-/-mice exhibit a defect in Th17 differentiation in vitro, and present evidence that the expression of SOCS1 and c-Maf contributes to the Th17 cell differentiation.Conclusion:miR-155 regulates Thl/Th17-related inflammation in chronic cardiac rejecton.