Foxp3-modified bone marrow mesenchymal stem cells promotes liver allograft tolerance through the generation of regulatory T cells in rats.

Zhongzhou Si,Jiequn Li,Yaxun Huang,Guangshun Chen,Haizhi Qi

doi:10.1186/s12967-015-0638-2

Abstract

BackgroundThe transcription factor forkhead box P3 (Foxp3) is a master regulatory gene necessary for the development and function of CD4+CD25+ regulatory T cells (Tregs). Mesenchymal stem cells (MSC) have recently emerged as promising candidates for cell-based immunosuppression/tolerance induction protocols. Thus, we hypothesized that MSC-based Foxp3 gene therapy would improve immunosuppressive capacity of MSC and induce donor-specific allograft tolerance in rat’s liver allograft model.MethodsThe present study utilized a lentivirus vector to overexpress the therapeutic gene Foxp3 on MSC. In vivo, Injections of 2 × 106 MSC, FUGW-MSC or Foxp3-MSC into the portal vein were carried out immediately after liver transplantation.ResultsSuccessful gene transfer of Foxp3 in MSC was achieved by lentivirus carrying Foxp3 and Foxp3-MSC engraftment in liver allograft was confirmed by fluorescence microscopy. Foxp3-MSC treatment significantly inhibited the proliferation of allogeneic ACI CD4+ T cells to splenocytes (SC) from the same donor strain or third-party BN rat compared with MSC. Foxp3-MSC suppressive effect on the proliferation of CD4+ T cells is contact dependent and associated with Programmed death ligand 1(PD-L1) upregulation in MSC. Co-culture of CD4+ T cells with Foxp3-MSC results in a shift towards a Tregs phenotype. More importantly, Foxp3-MSC monotherapy achieved donor-specific liver allograft tolerance and generated a state of CD4+CD25+Foxp3+ Tregs-dependent tolerance.ConclusionFoxp3-engineered MSC therapy seems to be a promising and attractive cell therapy approach for inducing immunosuppression or transplant tolerance.

Highlights

The transcription factor forkhead box P3 (Foxp3) is a master regulatory gene necessary for the development and function of CD4+CD25+ regulatory T cells (Tregs)
These finding suggests that Foxp3-Mesenchymal stem cells (MSC) successful locates in the liver allograft
Foxp3 transduction induced the expansion of Foxp3+ Tregs in vitro To determine whether or not the immunoregulatory actions of Foxp3-MSC were associated with the expansion of Tregs, CD4+ T cells were cocultured with MSC, Foxp3-MSC, or FUGW-MSC for 7d in the presence of antigen-presenting cell (APC) and anti-CD3 monoclonal antibody (mAb), and their FCM results were analyzed

Summary

Introduction

The transcription factor forkhead box P3 (Foxp3) is a master regulatory gene necessary for the development and function of CD4+CD25+ regulatory T cells (Tregs). We hypothesized that MSC-based Foxp gene therapy would improve immunosuppressive capacity of MSC and induce donor-specific allograft tolerance in rat’s liver allograft model. Transplant tolerance describes immunological unresponsiveness to donor alloantigens without the need for longterm administration of immunosuppressive drugs, while immune responsiveness to pathogens and malignant cells is maintained [1]. It is a major goal in transplantation. Qi et al J Transl Med (2015) 13:274 activity [4, 5] This potential may be amplified by transforming them with genes that will improve their therapeutic ability [4, 6]. All of these studies elegantly show the importance of Foxp3+ Tregs in MSC induced tolerance using Foxp3+ Tregs depletion or adoptive transfer of Foxp3+ Tregs studies [7, 8, 12, 15]

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Conclusion