Effects of blocking CD40/CD40L costimulatory pathway by RNA interference on the survival of mouse cardiac allograft

Abstract

Objective To investigate the effect of blocking CD40/CD40L costimulatory pathway by the lentiviral vector-mediated RNA interference on the survival of mouse cardiac allograft. Methods Mouse bone marrow-derived dendritic cells (DCs) were infected by CD40-RNAi lentiviral vector in vitro, and tolerogenic DCs (Tol-DCs) with decreased CD40 expression were prepared. Fluorescence real-time quantitative PCR and flow cytometry were used to analyze the expression of CD40 mRNA and DC surface antigens CD40, CD11c, MHC Ⅱ before and after infection. Mouse model of heterotropic abdominal heart transplantation was established. Seven days prior to heart transplantation, Tol-DCs with decreased CD40 expression were transfused into recipient mice intravenously (lentivirus infected DC group). Control group and non-infected DC group were assigned simultaneously. The survival of cardiac allograft was monitored and pathological grade of acute rejection 7 days after heterotropic abdominal heart transplantation was determined. Results The transcription of CD40 mRNA of DCs was down-regulated significantly at 48 h after CD40-RNAi lentiviral vector infection, and the inhibition rate was 80. 9%. The expression of CD40 protein was also significantly decreased as compared with control group (40. 07% ± 4. 03% ) ( P ＜ 0. 05 ).Compared to control group (8 ± 2 days) and non-infected DC group (9 ± 1 days), the survival time of cardiac allograft in CD40-RNAi lentivirus infected DC group (14 ± 4 days) was significantly prolonged (P＜ 0. 05 ), and the pathological grade of acute rejection decreased significantly ( P ＜ 0. 05 ).Conclusion Blocking CD40/CD40L costimulatory pathway could hamper the activation of allogeneic T lymphocyte, inhibit the acute rejection and prolong the survival of mouse cardiac allograft. Key words: RNA interference; Costimulatory pathway; Dendritic cell; CD40; Heart transplantation