Tryptanthrin is a bioactive component of indigo plants such as Polygonum tinctrorium and known to have an anti-inflammatory activity. The aim of this study was to investigate the effects of tryptanthrin on Toll-like receptor 3 (TLR3)-mediated cytokine and chemokine expression in human umbilical vein endothelial cells (HUVEC). Herein, we found that tryptanthrin suppressed the expression of CXCL10 in HUVEC upon stimulation with a TLR3 ligand polyinosinic-polycytidylic acid (poly IC). Tryptanthrin did not inhibit poly IC-induced activation of interferon regulatory factor 3 (IRF3) or the mRNA expression of interferon (IFN)-β, while it significantly suppressed the expression of RIG-I, MDA5, and classical IFN-stimulated genes (ISGs). Tryptanthrin attenuated the phosphorylation and nuclear translocation of STAT1 in HUVEC stimulated with not only poly IC but also recombinant IFN-β. These results suggested that tryptanthrin inhibited poly IC-induced expression of CXCL10 and ISGs via suppressing the activation of STAT1 in HUVEC. Our findings indicate that tryptanthrin may be useful for regulating TLR3-mediated vascular inflammation.

色胺酮是靛蓝植物如何首乌的生物活性成分。并且已知具有抗炎活性。这项研究的目的是研究类胰蛋白酶对人脐静脉内皮细胞（HUVEC）中Toll样受体3（TLR3）介导的细胞因子和趋化因子表达的影响。在本文中，我们发现，在用TLR3配体聚肌苷酸-聚胞苷酸（poly IC）刺激后，色胺酮抑制了HUVEC中CXCL10的表达。Tryptanthrin不会抑制多聚IC诱导的干扰素调节因子3（IRF3）的激活或干扰素（IFN）-β的mRNA表达，而它却能显着抑制RIG-1，MDA5和经典的IFN刺激基因（ISG）的表达。 ）。Tryptanthrin不仅减弱了poly IC的活性，还减弱了重组IFN-β刺激的HUVEC中STAT1的磷酸化和核易位。这些结果表明，色胺酮通过抑制HUVEC中STAT1的激活来抑制多聚IC诱导的CXCL10和ISG的表达。我们的发现表明，胰蛋白酶对调节TLR3介导的血管炎症可能有用。