Polysaccharide extracted from Portulacae Oleracea L. exerts protective effects against dextran sulfate sodium-induced colitis through inhibition of NF-?B.
ABSTRACT: Portulacae Oleracea L. (POL) is a traditional Chinese medicine and also an edible vegetable used to treat diarrhea in china for thousands years. Though the therapeutic effect has been proved in clinical trials, the concrete effective component and mechanisms remained elusive. Polysaccharide from POL has been extracted previously and the experiment suggested that POLP could diminish the weight loss and improve the health conditions of mice with DSS induced colitis. Hematoxylin & eosin staining revealed that POLP could improve the histopathological structure of the colon tissue. For the notably variation curve of TNF-? in control, colitis and treatment group, NF-?B was enrolled to investigate the molecular mechanisms of the protective effect of POLP. The protein expression level of NF-?Bp65 in cytoplasm increased after POLP treatment of the induced colitis. However, the protein level of NF-?Bp65 in the nucleus decreased after administration of POLP. The expression levels of I?B? and NF-?B related proteins Bcl-2 and survivin were also detected and the results suggested that POLP could inhibit the degradation of I?B? and decrease the protein levels of Bcl-2 and Survivin in colitis. It was concluded that POLP could improve the health condition of mice with DSS induced colitis and the mechanisms were closely related with NF-?B via inhibiting the degradation of I?B?.
Project description:Ferroptosis has recently emerged as an iron-dependent form of nonapoptotic cell death, which is also a regulated necrosis process and a response to tumor suppression. However, whether ferroptosis is involved in ulcerative colitis (UC) is unknown. The aims of this study were to investigate whether the ferroptosis is involved in UC, particularly intestinal epithelial cell (IEC) death, and to analyze the effect of the nuclear factor kappa Bp65 subunit (NF-?Bp65) on ferroptosis. The gene expression of ferroptosis-related proteins was assessed in intestinal mucosal samples from human UC. The experimental model of UC was induced with dextran sulfate sodium (DSS). Ferroptosis of IECs was evaluated, the effect of NF-?Bp65 on ferroptosis was analyzed by using IEC-specific NF-?Bp65-deleted mice (p65IEC-KO), and the ferroptosis signaling pathway was investigated in vitro and in vivo. The results showed that ferroptosis was significantly induced in the IECs from UC patients and mice with colitis, and the ferroptosis was mediated by endoplasmic reticulum (ER) stress signaling. The specific deletion of IEC NF-?Bp65 clearly upregulated ferroptosis and exacerbated colitis, and the result showed that phosphorylated-NF-?Bp65 significantly inhibited ER stress signaling by directly binding eukaryotic initiation factor 2?. These data indicate that ferroptosis contributes to UC via ER stress-mediated IEC cell death, and that NF-?Bp65 phosphorylation suppresses ER stress-mediated IEC ferroptosis to alleviate UC. The results suggest that ferroptosis involves in IEC death in UC, NF-?Bp65 play a critical role in the ferroptotic inhibition, and ferroptosis is a potential therapeutic target for UC.
Project description:We examined the effect of bortezomib, a proteasome inhibitor, on the development of dextran sulfate sodium (DSS)-induced colitis in mice. DSS-colitis was induced by the administration of 3% DSS in water in C57BL/6J mice. Bortezomib was intraperitoneally administered daily for 9 days from the start of DSS. Ubiquitination of I?B? was evaluated by immunoblot. Bortezomib significantly ameliorated DSS-induced body weight loss and reduced the disease activity. The translocation of NF-?Bp65 into the nucleus was markedly suppressed in the DSS + bortezomib group compared to the DSS group, but this difference was not detected in submucosal tissue. Ubiquitinated I?B? in the cytoplasm of colon epithelial cells was increased in the DSS + bortezomib group compared to the DSS group. In HT-29 cells, bortezomib blocked tumor necrosis factor-? (TNF-?)-induced nuclear translocation of NF-?B and this was accompanied by an increase in ubiquitinated I?B? in the cytoplasm. The mRNA expression of inflammatory mediators in colonic epithelial cells was significantly reduced by the treatment of bortezomib. Bortezomib inhibited the nuclear translocation of NF-?B in colonic epithelial cells by suppressing the degradation of I?B? and contributed to an improvement in DSS colitis. Our study suggests that bortezomib may be a new treatment option for IBD.
Project description:Bcl-3 is an atypical member of the inhibitor of kappa light polypeptide gene enhancer in B-cells (I?B) family. It associates with p50/nuclear factor-?B1 (NF-?B1) and p52/NF-?B2 homodimers in nuclei where it modulates transcription in a context-dependent manner. A subset of B-cell tumors exhibits recurrent translocations of Bcl-3, resulting in overexpression. Elevated expression without translocations is also observed in various B-cell lymphomas and even some solid tumors. Here we investigated the role of Bcl-3 in azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colon tumors, a mouse model for colitis-associated colorectal cancers in humans. Contrary to expectations, Bcl-3 suppressed colorectal tumor formation: Bcl-3-deficient mice were relatively protected from DSS-induced epithelial damage and developed more polyps after AOM/DSS treatment, although polyp size was unaffected. DSS-challenged mutant mice exhibited increased recruitment of myeloid-derived suppressor cells, consistent with protection of the epithelium. Loss of Bcl-3 in intestinal epithelial cells was sufficient to increase tumorigenesis. The added tumor burden in mutant mice was dependent on tumor necrosis factor-? (TNF?), a tumorigenic, NF-?B-mediated signaling pathway that was dampened by Bcl-3. These findings reveal a tumor-suppressive role for Bcl-3 in this inflammation-associated cancer model. Bcl-3 thus functions as a tumor promoter or suppressor, depending on the cellular and environmental context.
Project description:Huangqin-tang (HQT) is a traditional Chinese medicine (TCM) formula widely used for the treatment of inflammatory bowel disease in China. However, the molecular mechanisms by which HQT protects the colon are unclear. We studied the protective effects of HQT and the underlying mechanisms in an experimental mouse model and in vitro. In vivo, dextran sodium sulphate (DSS)-induced acute and chronic colitis were significantly ameliorated by HQT as gauged by phenotypic, histopathologic and inflammatory manifestations of the disease. Mechanistically, DSS-induced nuclear factor-?B (NF-?B) signalling was inhibited by HQT. Moreover, HQT-treated mice demonstrated significant changes in cell apoptosis, expression of apoptosis-associated genes such as caspase-3, bax, bcl-2, and intestinal permeability. HQT also increased occluding and zonula occludens-1 (ZO-1), inhibited cell proliferation (Ki67), and increased regulatory T cells numbers, protein expression of Foxp3 and IL-10 in the colonic tissue. In vitro, HQT down-regulated production of pro-inflammatory cytokines and supressed the NF-?B signalling pathway in lipopolysaccharides-induced RAW 264.7 macrophages. Our study suggests that HQT plays a critical role in regulating intestinal epithelial cell homeostasis, inflammation and immune response in colitis and offers novel therapeutic options in the management of inflammatory bowel disease.
Project description:Inflammatory macrophages in colonic mucosa are the leading drivers of the pathology associated with inflammatory bowel disease (IBD). Here we examined whether gadolinium chloride (GdCl3), a macrophage selective inhibitor, would improve the course of 2,4,6-trinitro benzene sulfonic acid (TNBS) and dextran sodium sulfate (DSS)-induced colitis in mice and the potential mechanisms were investigated. By giving GdCl3 to colitis mice through intravenous or intrarectal route, we found that GdCl3 markedly ameliorated the colitis severity, including less weight loss, decreased disease activity index scores, and improved mucosal damage. To investigate the potential mechanisms, flow-cytometric analysis was performed to detect the proportion of mucosal macrophages in colon. The results showed that GdCl3 had no macrophage depletion effect in colonic mucosa, but significantly suppressed TNBS and DSS-induced TNFα, IL-1β and IL-6 secretions. Also, Western blotting analysis indicated that NF-κB p65 expression was significantly attenuated in the mucosa in colitis mice with GdCl3 treatment. Then, the anti-inflammatory activity of GdCl3 was confirmed in LPS-stimulated RAW 264.7 cells that GdCl3 might down-regulate the production of proinflammatory cytokines by macrophages through inhibition of the NF-κB signaling pathway. Therefore, intervention with mucosal inflammatory macrophages may be a promising therapeutic target in IBD.
Project description:Guchang capsule (GC) is a Chinese materia medica standardized product extracted from 15 Chinese traditional medical herbs and it has been clinically used in the treatment of intestinal disease. In this study, in order to extend the research of GC in intestinal disease, we were aiming to evaluate potential effects of GC on dextran sulphate sodium- (DSS-) induced murine experimental colitis and to elucidate the underlying mechanisms. GC treatment attenuated DSS-induced body weight loss and reduced the mortality. Moreover, GC treatment prevented DSS-induced colonic pathological damage; meanwhile it inhibited proinflammatory cytokines production in colon tissues. In vitro, GC significantly reduced LPS-induced proinflammatory cytokines production via inhibiting the activation of NF-?B in macrophage cells, and the expressions of several long noncoding RNAs (lncRNAs) which were reported in regulating NF-?B signaling pathway were obviously affected by adding GC into culture medium. In conclusion, our data suggested that administration of GC exhibits therapeutic effects on DSS-induced colitis partially through regulating the expression of NF-?B related lncRNAs in infiltrating immune cells.
Project description:Objective:Huangqin decoction (HQD), a classical traditional Chinese medicinal formula, has been commonly used to treat gastrointestinal diseases for thousands of years. We investigated the anti-inflammatory effects and underlying mechanisms of HQD on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). Methods:Experimental mice were given 3% DSS, and HQD (2.275, 4.55, and 9.1 g/kg), or mesalazine (ME, 200 mg/kg) orally for 7 days. Body weight loss, disease activity index (DAI), colon length, histology, and levels of inflammatory cytokines were measured to evaluate the effects of HQD on colitis. The effects of HQD on the Ras-phosphoinositide-3-kinase (PI3K)-Akt-hypoxia inducible factor 1 alpha (HIF-1?) and nuclear factor-kappa B (NF-?B) pathways were evaluated by Western blot analysis. In addition, the gut microbiota was characterized using high-throughput Illumina MiSeq sequencing. Results:The results showed that HQD significantly reduced the body weight loss, ameliorated DAI, restored colon length, and improved the intestinal epithelial cell barrier in mice with DSS-induced colitis. The messenger RNA (mRNA) expression levels of inflammatory mediators were decreased following HQD treatment. Furthermore, the Ras-PI3K-Akt-HIF-1? and NF-?B pathways were significantly inhibited by HQD. Finally, treatment with HQD resulted in recovery of gut microbiota diversity. Conclusions:HQD ameliorates DSS-induced colitis through regulation of the gut microbiota, and suppression of Ras-PI3K-Akt-HIF-1? and NF-?B pathways. Our results suggested that HQD may be a potential candidate for treatment of UC.
Project description:Increasing evidence suggests that the aryl hydrocarbon receptor (AhR) pathway has an important role in the regulation of inflammatory responses. Most recently, we have shown that the activation of the AhR pathway by a potent AhR agonist inhibits the development of dextran sodium sulfate (DSS)-induced colitis, a model of human ulcerative colitis, by the induction of prostaglandin E2 (PGE2) in the large intestine. Because several strains of probiotic lactic acid bacteria have been reported to inhibit DSS-induced colitis by unidentified mechanisms, we hypothesized that particular strains of lactic acid bacterium might have the potential to activate the AhR pathway, thereby inhibiting DSS-induced colitis. This study investigated whether there are specific lactic acid bacterial strains that can activate the AhR pathway, and if so, whether this AhR-activating potential is associated with suppression of DSS-induced colitis. By using AhR signaling reporter cells, we found that Lactobacillus bulgaricus OLL1181 had the potential to activate the AhR pathway. OLL1181 also induced the mRNA expression of cytochrome P450 family 1A1 (CYP1A1), a target gene of the AhR pathway, in human colon cells, which was inhibited by the addition of an AhR antagonist, ?-naphthoflavon (?NF). In addition, mice treated orally with OLL1181 showed an increase in CYP1A1 mRNA expression in the large intestine and amelioration of DSS-induced colitis. Thus, OLL1181 can induce activation of the intestinal AhR pathway and inhibit DSS-induced colitis in mice. This strain of lactic acid bacterium has therefore the potential to activate the AhR pathway, which may be able to suppress colitis.
Project description:Bcl-3 is an atypical NF-?B family member that regulates NF-?B-dependent gene expression in effector T cells, but a cell-intrinsic function in regulatory T (Treg) cells and colitis is not clear. Here we show that Bcl-3 expression levels in colonic T cells correlate with disease manifestation in patients with inflammatory bowel disease. Mice with T-cell-specific overexpression of Bcl-3 develop severe colitis that can be attributed to defective Treg cell development and function, leading to the infiltration of immune cells such as pro-inflammatory ??T cells, but not ?? T cells. In Treg cells, Bcl-3 associates directly with NF-?B p50 to inhibit DNA binding of p50/p50 and p50/p65 NF-?B dimers, thereby regulating NF-?B-mediated gene expression. This study thus reveals intrinsic functions of Bcl-3 in Treg cells, identifies Bcl-3 as a potential prognostic marker for colitis and illustrates the mechanism by which Bcl-3 regulates NF-?B activity in Tregs to prevent colitis.
Project description:As they undergo phagocytosis, most early apoptotic cells negatively regulate proinflammatory signaling and were suggested as a major mechanism in the resolution of inflammation. The dextran sulfate sodium model is generally viewed as an epithelial damage model suited to investigate innate immune responses. Macrophages primed with LPS and subsequently exposed to DSS secrete high levels of IL-1? in an NLRP3-, ASC-, and caspase-1-dependent manner. The aim of this research was to test the therapeutic effect of a single dose of apoptotic cells in a DSS-colitis model and to explore possible mechanisms. Primary peritoneal macrophages, the DSS mice model, and Nlrp3-deficient mice, were used to assess the effect apoptotic cells on colitis. Immunohistochemistry, flow-cytometer, and western blots helped to explore the effect and mechanisms. Using a variety of NLRP3 triggering mechanisms, we show that apoptotic cells negatively regulate NF-?B and NLRP3 activation in primary peritoneal macrophages, at pre- and post-transcription levels, via inhibition of reactive oxygen species, lysosomal stabilization, and blocking K+ efflux. This property of apoptotic cells is demonstrated in a dramatic clinical, histological, and immunological amelioration of DSS colitis in Balb/c and B6 mice following a single administration of apoptotic cells.