Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, No. 305 East Zhongshan Road, Nanjing, PR China.
Int Immunopharmacol. 2013 Jun;16(2):268-74. doi: 10.1016/j.intimp.2013.04.018. Epub 2013 Apr 30.
IL-6/STAT3/SOCS3 signaling pathway plays an important role in the pathogenesis of Crohn's disease by induction of the antiapoptotic factors Bcl-2 and Bcl-xl in lamina propria mononuclear cells (LPMCs). We previously reported that triptolide showed therapeutic activity in mouse colitis by mechanisms involving suppression of IL-6 trans-signaling. IL-10 gene-deficient mice with established colitis were used for the experiments with triptolide administration.
This study further investigates the mechanism by which triptolide attenuates Crohn's colitis. IL-10 gene-deficient mice (IL-10(-)/(-)) of 10-12weeks with established colitis were used for the experiments with chronic triptolide administration. Apoptosis of lamina propria mononuclear cells (LPMCs) were measured by flow cytometry. SOCS, Bcl-2, Bcl-xl and Bax were determined by Western blot. Furthermore, an in vitro study was performed by using cultured intestine from CD patients to observe the direct effects of triptolide.
Our data indicated triptolide promoted apoptosis in LPMCs in vivo. Interestingly, triptolide significantly induced the apoptosis of LP-CD4-positive but not LP-CD4-negative cells. Triptolide significantly induced SOCS3 protein and reduced STAT3 target anti-apoptotic genes Bcl-2 and Bcl-xl in LPMCs. The results were confirmed by an in vitro study using colonic explants cultured with triptolide.
Our results indicated that triptolide therapy may restore the homeostatic balance of LP-T cell apoptosis within the gut, and demonstrate a novel mechanism of action of triptolide therapy mediated through regulation IL-6/STAT3/SOCS3 signaling pathway.
IL-6/STAT3/SOCS3 信号通路通过诱导固有层单核细胞（LPMCs）中的抗凋亡因子 Bcl-2 和 Bcl-xl 在克罗恩病的发病机制中发挥重要作用。我们之前报道三萜内酯通过抑制 IL-6 转信号发挥治疗作用在小鼠结肠炎中具有治疗活性。使用已建立结肠炎的 IL-10 基因缺陷小鼠进行三萜内酯给药实验。
本研究进一步探讨了三萜内酯减轻克罗恩病的机制。使用已建立结肠炎的 10-12 周龄 IL-10 基因缺陷小鼠（IL-10(-/-)）进行慢性三萜内酯给药实验。通过流式细胞术测量固有层单核细胞（LPMCs）的凋亡。通过 Western blot 测定 SOCS、Bcl-2、Bcl-xl 和 Bax。此外，通过使用来自 CD 患者的培养肠进行体外研究来观察三萜内酯的直接作用。
我们的数据表明三萜内酯在体内促进 LPMCs 凋亡。有趣的是，三萜内酯显着诱导 LP-CD4-阳性但不诱导 LP-CD4-阴性细胞的凋亡。三萜内酯显着诱导 SOCS3 蛋白并减少 LPMCs 中的 STAT3 靶抗凋亡基因 Bcl-2 和 Bcl-xl。通过使用三萜内酯培养的结肠外植体进行的体外研究证实了这一结果。
我们的结果表明，三萜内酯治疗可能恢复肠道内 LP-T 细胞凋亡的体内稳态平衡，并证明三萜内酯治疗通过调节 IL-6/STAT3/SOCS3 信号通路发挥作用的新机制。
