| ObjectiveUlcerative colitis(UC)is a chronic,idiopathic inflammatory disease of the intestine involving the rectum and distal colon,with an unknown etiology and a prolonged period of relapse and remission,which is closely related to the occurrence and development of colorectal cancer.Although there have been new advances in the treatment of UC in recent years,a complete cure for UC has not yet been found due to its complex pathogenesis.Therefore,the active search and development of new drugs for the treatment of UC may provide useful exploration in the prevention and treatment of UC.The pathogenesis of UC involves several aspects:genetic,environmental,intestinal flora,and immune imbalance,among which,the dysregulated immune response is closely related to the development of UC.Studies have confirmed that the interaction of several immune factors in the body contributes to the development of UC,and in particular,intestinal Th17/Treg cell imbalance plays an important regulatory role in the pathogenesis of UC.It is thought that Th17 cells are involved in the inflammatory response by secreting pro-inflammatory factors such as IL-17,IL-21,and IL-22,whereas Treg cells,which are characterized by the expression of Forkhead box protein p3(Foxp3),secrete suppressive inflammatory factors such as TGF-βto suppress the autoimmune response.Zingerone(Zin)is a natural and non-toxic phenolic compound derived from ginger with significant anti-inflammatory,anti-oxidative stress,and anti-tumor effects.Studies have shown that Zin could alleviate experimental colitis induced by dextran sodium sulfate(DSS)and trinitrobenzene-sulfonic acid(TNBS)by inhibiting the NF-k B pathway.Moreover,a recent study showed that it exerts anti-cancer activity in breast cancer through a T cell-mediated immune response.However,the role of Zin in T-cell immunomodulation of intestinal inflammation has not been reported.In this study,we aim to preliminarily investigate the immunomodulatory mechanism of Zin in treating UC by observing the efficacy of Zin on DSS-induced acute colitis and analyzing the effect of Zin on CD4~+T cell subpopulation differentiation in vivo and in vitro,respectively.Methods1.The DSS solution was routinely applied to establish an acute UC model in C57BL/6mice and to evaluate the therapeutic effect of Zin on mice with colitis.2.RT-q PCR and multi-factor assay were used to analyze the expression of m RNA and protein of relevant inflammatory factors in the intestine of mice.3.Flow cytometry analysis of the ratio of Th17 cells and Treg cell subpopulations in the lamina propria lymphocytes of the mouse intestine.4.In vitro T cell induction differentiation assay was conducted to analyze the effects of Zin on T cell proliferation,apoptosis,and differentiation of Th1,Th17,and Treg cell subpopulations.5.GAL4-RORγt dual luciferase reporter gene system was applied to detect the effect of Zin on RORγt transcriptional activity in 293T cells.6.Molecular docking study was to investigate the interaction of Zingerone with the RORγt ligand binding domain(LBD).Results1.Zin has a protective effect against DSS-induced colitis,inhibiting the expression of pro-inflammatory cytokines in the intestine but up-regulating the expression of anti-inflammatory factors.2.Zin reduced the proportion of Th17 cells and RORγt-positive cells in CD4~+T cells but increased the proportion of Treg cells in the intestine of mice.3.T-cell culture in vitro showed that Zin could inhibit Th17 cell differentiation but promote Treg cell differentiation in a dose-dependent manner at concentrations that did not affect T cell proliferation and apoptosis,and could inhibit RORγt expression.4.The results of the dual luciferase reporter gene indicated that Zin inhibited the transcriptional activity of RORγt in 293T cells in a dose-dependent manner.5.The molecular docking result suggested that Zin interacts with the ligand binding domain(LBD)of RORγt.ConclusionZin ameliorates DSS-induced ulcerative colitis in mice by regulating Th17/Treg cell homeostasis and inhibiting RORγt. |
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