Objective: Interferon-γ (IFN-γ) is known to enhance the immunosuppressive properties of mesenchymal stem cells (MSCs). The aim of this study was to determine whether gene modification with IFN-γ-expression plasmids could boost the therapeutic effects of MSCs on DSS-induced colitis.
Methods: We first reconstructed pcDNA3.1-IFNγ plasmids, transfected them to human umbilical cord derived MSCs, and detected the basic characters of MSCs including immune phenotype, cell vitality, proliferation, apoptosis and cell cycle progression after transfection. Subsequently, we analyzed the inhibition effect of IFN-γ-MSCs on T cell proliferation in vitro. Finally, we induced colitis in female C57BL/6 mice by 3 % DSS treatment and evaluated the therapeutic efficacy of IFN-γ-MSCs on colitis.
Results: Transfection with pcDNA3.1-IFNγ did not change the basic characters of MSCs. Interestingly, IFN-γ-MSCs showed more potent immunosuppressive effects on the proliferation of T cells compared to normal MSCs. Furthermore, systemic infusion with IFN-γ-MSCs more efficiently ameliorated DSS-induced mouse colitis including colitis-related ease of body weight, increase of colon length, decrease of disease activity index, and improvement of small intestine tissues structure. In addition, IFN-γ-MSCs increased the populations of Foxp3(+) Tregs and Th2 cells both in mesenteric lymph node and spleen, upregulated indoleamine 2, 3-dioxygenase expression, and suppressed inflammatory cytokine production in mouse colon.
Conclusions: Gene delivery with IFN-γ-expression plasmids enhanced the therapeutic effects of MSCs on DSS-induced mouse colitis. This study provides an effective therapeutic strategy of MSCs for inflammatory diseases.