Journal Article

Synergic silencing of costimulatory molecules prevents cardiac allograft rejection

Zhang, Xusheng, Jiang, Alex T, Liu, Yanling, Chen, Ruiqi, Shi, Jun, Min, Wei-Ping, Quan, Douglas, Zhang, Guangfeng, Zhang, Xiao, Johnston, Nathan, Siu, King Sun, Lian, Dameng, Zhang, Zhu-Xu, Koos, David, Zheng, Xiufen

2014

Overview

Background While substantial progress has been made in blocking acute transplant rejection with the advent of immune suppressive drugs, chronic rejection, mediated primarily by recipient antigen presentation, remains a formidable problem in clinical transplantation. We hypothesized that blocking co-stimulatory pathways in the recipient by induction of RNA interference using small interference RNA (siRNA) expression vectors can prolong allogeneic heart graft survival. Method Vectors expressing siRNA specifically targeting CD40 and CD80 were prepared. Recipients (BALB/c mice) were treated with CD40 and/or CD80 siRNA expression vectors via hydrodynamic injection. Control groups were injected with a scrambled siRNA vector and sham treatment (PBS). After treatment, a fully MHC-mismatched (BALB/c to C57/BL6) heart transplantation was performed. Result Allogeneic heart graft survival (>100 days) was approximately 70% in the mice treated simultaneously with CD40 and CD80 siRNA expression vectors with overall reduction in lymphocyte interstitium infiltration, vascular obstruction, and edema. Hearts transplanted into CD40 or CD80 siRNA vector-treated recipients had an increased graft survival time compared to negative control groups, but did not survive longer than 40 days. In contrast, allogenic hearts transplanted into recipients treated with scrambled siRNA vector and PBS stopped beating within 10–16 days. Real-time PCR (RT-PCR) and flow cytometric analysis showed an upregulation of FoxP3 expression in spleen lymphocytes and a concurrent downregulation of CD40 and CD80 expression in splenic dendritic cells of siRNA-treated mice. Functional suppressive activity of splenic dendritic cells (DCs) isolated from tolerant recipients was demonstrated in a mixed lymphocyte reaction (MLR). Furthermore, DCs isolated from CD40- and CD80-treated recipients promoted CD4 + CD25 + FoxP3+ regulatory T cell differentiation in vitro. Conclusion This study demonstrates that the simultaneous silencing of CD40 and CD80 genes has synergistic effects in preventing allograft rejection, and may therefore have therapeutic potential in clinical transplantation.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V
• Subject: Analysis / Animals / Antigens / B7-1 Antigen - genetics / Base Sequence / Biomedical and Life Sciences / Biomedicine / Bone marrow / CD40 Antigens - genetics / Cell / Dendritic cells / DNA Primers / Flow Cytometry / Gene Silencing / Genes / Graft Rejection - genetics / Graft Rejection - prevention & control / Health aspects / Heart Transplantation / Lymphocyte Culture Test, Mixed / Male / Medical research / Medicine/Public Health / Mice / Mice, Inbred BALB C / Mice, Inbred C57BL / Physiological aspects / Real-Time Polymerase Chain Reaction / RNA, Small Interfering - genetics / Rodents / Studies / T cell receptors / tissue and gene therapy / Transplants & implants