SOCS1 is a key regulator of cytokine signaling and is important for maintaining balance in the immune system. It is thought to participate in negative feedback loops in cytokine signaling and may be an important signal for the regulation of dendritic cell （DC） maturation. However, it remains unclear whether DCs transduced with SOCS1 exhibit characteristics of regulatory DCs and induce allogeneic T-cell hyporesponsiveness. In this study, we constructed adenovirai vector coding SOCS1 （Ad-SOCS1） that can efficiently increase SOCS1 gene expression in bone marrow-derived dendritic cells. DCs transduced with Ad-SOCS1 （DC-SOCS1） expressed low levels of costimulatory and MHC molecules, were resistant to maturation and activation stimulation, induced allogeneic T-cell hyporesponsiveness, and promoted the generation of regulatory-like T cells in vitro. DC-SOCS1 pretreatment significantly prolonged the survival of ailografts and led to a substantial increase in the generation of regulatory T cells. Our data suggest that SOCS1 inhibits DC maturation and induces regulatory DC generation, therefore possessing therapeutic potential to prevent rejection in organ transplantation.
Hong FuShaohua SongFang LiuZhijia NiXiaoyun ShenLiang XiaoGuoshan DingQuanxing Wang
Suberoylanilide hydroxamic acid （SAHA）, as a histone deacetylase （HDAC） inhibitor （HDACi）, was recently found to exhibit an immunosuppressive effect. However, whether SAHA can synergize with calcineurin inhibitors （CNIs） to inhibit allograft rejection and its underlying mechanism remain elusive. In this study, we demonstrated the synergistic effects of SAHA and non-therapeutic dose of tacrolimus （FK506） in prolonging the allograft survival in a murine cardiac transplant model. Concomitant intragraft examination revealed that allografts from SAHA-treated recipients showed significantly lower levels of IL-17 expression, and no discernable difference for IL-17 expressions was detected between SAHA- and SAHA/FK506-treated allograft as compared with allografts from FK506-treated animals. In contrast, administration of FK506 significantly suppressed interferon （IFN）-y but increased IL-IO expression as compared with that of SAHA-treated animals, and this effect was independent of SAHA. Interestingly, SAHA synergizes with FK506 to promote Foxp3 and CTLA4 expression. In vitro, SAHA reduced the proportion of Th17 cells in isolated CD4＋ T-cell population and decreased expressions of IL-17A, IL-17F, STAT3 and RORyt in these cells. Moreover, SAHA enhances suppressive function of regulatory T （Treg） cells by upregulating the expression of CTLA-4 without affecting T effector cell proliferation, and increased the proportion of Treg by selectively promoting apoptosis of T effector cells. Therefore, SAHA, a HDACi, may be a promising immunosuppressive agent with potential benefit in conjunction with CNI drugs.
Xin ZhangShu HannYindong KangMeng GuoShanjuan HongFang LiuShangxi FuLiming WangQuan-Xing Wang
