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[Display omitted] • Arctigenin improves colitis in mice by promoting colonic mucosal healing. • Arctigenin promotes colonic mucosal healing by stimulating epithelial cell migration. • Arctigenin promotes colonic epithelial cell migration by enhancing focal adhesion assembly. • Arctigenin accelerates focal adhesion assembly by directly binding and activating FAK. • FAK activation is notably decreased in colon epithelial cells of UC patients. Colonic mucosal defect constitutes the major reason of recurrence and deterioration of ulcerative colitis (UC), and mucosal healing has become the therapeutic endpoint of UC. Unfortunately, specific promoter of mucosal healing is still absent. Our previous researches demonstrated that arctigenin could alleviate colitis symptoms in mice, but whether it has a positive impact on colonic mucosal healing remains unclear. This study explores whether and how arctigenin promotes mucosal healing. Orally administered arctigenin was shown to alleviate colitis in mice primarily by enhancing mucosal healing. In vitro , arctigenin was shown to promote the wound healing by accelerating colonic epithelial cell migration but not proliferation. Acceleration of the focal adhesion turnover, especially assembly, is crucial for arctigenin promoting the cell migration. Arctigenin was able to activate focal adhesion kinase (FAK) in colonic epithelial cells through directly binding with Tyr251 site of FAK, as evidenced by surface plasmon resonance assay and site-directed mutagenesis experiment. In the colonic epithelial cells of UC patients and colitis mice, FAK activation was significantly down-regulated compared with the controls. Arctigenin promoted colonic epithelial cell migration and mucosal healing in dextran sulphate sodium (DSS)-induced colitis mice dependent on activating FAK, as confirmed by combined use with FAK inhibitor. In summary, arctigenin can directly promote mucosal healing in colitis mice through facilitating focal adhesion turnover, especially assembly, and consequent migration of epithelial cells via targeting FAK. Arctigenin may be developed as a mucosal healing promoter, and FAK is a potential therapeutic target for UC and other mucosal defect-related diseases. [ABSTRACT FROM AUTHOR]

Arctigenin, the major active constituent of Fructus Arctii, has been reported to inhibit the growth of various tumors and alleviate colitis. This study aimed to prove the protective effect of arctigenin on colitis-associated cancer (CAC) and explore its mechanisms. Orally administered arctigenin prevented the progression of colitis and protected against colon carcinogenesis in azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced CAC mice. Arctigenin downregulated NLRP3 inflammasome activation and fatty acid oxidation (FAO) metabolism in macrophages, as determined by untargeted metabolomics. Arctigenin also inhibited the expression of carnitine palmitoyltransferase 1 (CPT1), reduced the acetylation of α-tubulin, and disrupted NLRP3 complex formation, which in turn inactivated the NLRP3 inflammasome. Downregulation of the CPT1-FAO-acetyl-coenzyme A (acetyl-CoA)-acetylated α-tubulin pathway was observed to inhibit the effect of arctigenin on NLRP3 inflammasome assembly, as confirmed by CPT1 overexpression. Lastly, arctigenin was shown to inhibit NLRP3 inflammasome activation and improve CAC in mice, and the effect was significantly diminished by the overexpression of adeno-associated virus (AAV)9-CPT1. Taken together, these results show that the inhibition of NLRP3 inflammasome assembly in macrophages due to FAO downregulation contributes to the preventative effect of arctigenin against CAC. Our findings highlight the potential value of arctigenin to reduce the risk of CAC in patients with colitis. [ABSTRACT FROM AUTHOR]

Intestinal epithelial barrier dysfunction is deeply involved in the pathogenesis of inflammatory bowel diseases (IBD). Arctigenin, the main active constituent in Fructus Arctii (a traditional Chinese medicine), has previously been found to attenuate colitis induced by dextran sulfate sodium (DSS) in mice. The present study investigated whether and how arctigenin protects against the disruption of the intestinal epithelial barrier in IBD. Arctigenin maintained the intestinal epithelial barrier function of mice with DSS‐ and TNBS‐induced colitis. In Caco‐2 and HT‐29 cells, arctigenin lowered the monolayer permeability, increased TEER, reversed the abnormal expression of tight junction proteins, and restored the altered localization of F‐actin induced by TNF‐α and IL‐1β. The specific antagonist PHTPP or shRNA of ERβ largely weakened the protective effect of arctigenin on the epithelial barrier function of Caco‐2 and HT‐29 cells. Molecular docking demonstrated that arctigenin had high affinity for ERβ mainly through hydrogen bonds as well as hydrophobic effects, and the protective effect of arctigenin on the intestinal barrier function was largely diminished in ERβ‐mutated (ARG346 and/or GLU305) Caco‐2 cells. Moreover, arctigenin‐blocked TNF‐α induced increase of the monolayer permeability in Caco‐2 and HT‐29 cells and the activation of myosin light chain kinase (MLCK)/myosin light chain (MLC) pathway in an ERβ‐dependent manner. ERβ deletion in colons of mice with DSS‐induced colitis resulted in a significant attenuation of the protective effect of arctigenin on the barrier integrity and colon inflammation. Arctigenin maintained the integrity of the intestinal epithelial barrier under IBD by upregulating the expression of tight junction proteins through the ERβ‐MLCK/MLC pathway. [ABSTRACT FROM AUTHOR]

Arctigenin, the main effective constituent of Arctium lappa L. fruit, has previously been proven to dramatically attenuate dextran sulfate sodium (DSS)-induced colitis in mice, a frequently used animal model of inflammatory bowel disease (IBD). As Th1 and Th17 cells play a crucial role in the pathogenesis of IBD, the present study addressed whether and how arctigenin exerted anti-colitis efficacy by interfering with the differentiation and activation of Th1/Th17 cells. In vitro , arctigenin was shown to markedly inhibit the differentiation of Th17 cells from naïve T cells, and moderately inhibit the differentiation of Th1 cells, which was accompanied by lowered phosphorylation of STAT3 and STAT4, respectively. In contrast, arctigenin was lack of marked effect on the differentiation of either Th2 or regulatory T cells. Furthermore, arctigenin was shown to suppress the mammalian target of rapamycin complex 1 (mTORC1) pathway in T cells as demonstrated by down-regulated phosphorylation of the downstream target genes p70S6K and RPS6, and it functioned independent of two well-known upstream kinases PI3K/AKT and ERK. Arctigenin was also able to inhibit the activity of mTORC1 by dissociating raptor from mTOR. Interestingly, the inhibitory effect of arctigenin on T cell differentiation disappeared under a status of mTORC1 overactivation via knockdown of tuberous sclerosis complex 2 (TSC2, a negative regulator of mTORC1) or pretreatment of leucine (an agonist of mTOR). In DSS-induced mice, the inhibition of Th1/Th17 responses and anti-colitis effect of arctigenin were abrogated by leucine treatment. In conclusion, arctigenin ameliorates colitis through down-regulating the differentiation of Th1 and Th17 cells via mTORC1 pathway. [ABSTRACT FROM AUTHOR]

The crude powder of the fruit of Arctium lappa L. (ALF) has previously been reported to attenuate experimental colitis in mice. But, its main effective ingredient and underlying mechanisms remain to be identified. In this study, ALF was extracted with ethanol, and then successively fractionated into petroleum ether, ethyl acetate, n -butanol and water fraction. Experimental colitis was induced by dextran sulfate sodium (DSS) in mice. Among the four fractions of ALF, the ethyl acetate fraction showed the most significant inhibition of DSS-induced colitis in mice. The comparative studies of arctigenin and arctiin (the two main ingredients of ethyl acetate fraction) indicated that arctigenin rather than arctiin could reduce the loss of body weight, disease activity index and histological damage in the colon. Arctigenin markedly recovered the loss of intestinal epithelial cells (E-cadherin-positive cells) and decreased the infiltration of neutrophils (MPO-positive cells) and macrophages (CD68-positive cells). Arctigenin could down-regulate the expressions of TNF-α, IL-6, MIP-2, MCP-1, MAdCAM-1, ICAM-1 and VCAM-1 at both protein and mRNA levels in colonic tissues. Also, it markedly decreased the MDA level, but increased SOD activity and the GSH level. Of note, the efficacy of arctigenin was comparable or even superior to that of the positive control mesalazine. Moreover, it significantly suppressed the phosphorylation of MAPKs and the activation of NF-κB, including phosphorylation of IκBα and p65, p65 translocation and DNA binding activity. In conclusion, arctigenin but not arctiin is the main active ingredient of ALF for attenuating colitis via down-regulating the activation of MAPK and NF-κB pathways. [ABSTRACT FROM AUTHOR]