Saikosaponin-d ameliorates dextran sulfate sodium-induced colitis by suppressing NF-κB activation and modulating the gut microbiota in mice

Saikosaponin-d (SSd), extracts from Bupleurum falcatum L, exhibits anti-inflammatory and anti-infectious activities. However, the effect of SSd on intestinal inflammation has not been investigated. The aim of this study was to evaluate the effect of SSd on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice, and to elucidate the underlying mechanisms. UC was induced in mice by administrating 3% DSS in drinking water for 7 days. SSd (4 mg/kg and 8 mg/kg) was administered by gavage every day during the experimental process. The results showed that SSd treatment (8 mg/kg) significantly ameliorated UC mice by decreasing disease activity index (DAI), increasing colon length and improving pathological characteristics. SSd treatment (8 mg/kg) significantly suppressed the mRNA levels of pro-inflammatory cytokines including TNF-α, IL-6 and IL-1β, increased that of anti-inflammatory cytokine IL-10. Furthermore, SSd (8 mg/kg) suppressed the activation of NF-κB by decreasing the degradation and phosphorylation of IκB. SSd (8 mg/kg) also protected the intestinal barrier by increasing the mRNA levels of mucin (Muc1 and Muc2) and the protein levels of zonula occludens-1 (ZO-1) and Claudin-1. The 16S rDNA gene high-throughput sequencing revealed that SSd treatment (8 mg/kg) increased the alpha diversity and regulated the structure of gut microbiota in UC mice. Taken together, our findings demonstrated that SSd (8 mg/kg) improved DSS-induced intestinal inflammation by inhibiting NF-κB activation and regulated the gut microbiota.     

Curcumin represses the activity of inhibitor-κB kinase in dextran sulfate sodium-induced colitis by S-nitrosylation

In this study, we investigated the preventive effects of curcumin using dextran sulfate sodium (DSS)-induced colitis and the potential role of curcumin in regulation of anti-inflammation through S-nitrosylation. After curcumin treatment for 6 days, the body weight and disease activity index of DSS-induced mice was alleviated and the colonic length was also rescued. Western blot presented that the protein expression of iNOS can be reduced by curcumin. Consistently, mRNA level of iNOS and pro-inflammatory cytokines, such as TNFα, IL-1β, and IL-6, was also repressed. Moreover, Curcumin reduced the amount of nitrite in DSS-induced colitis but not affected total S-nitrosylation level on proteins on day 6, indicating that curcumin inhibited NO oxidation. Furthermore, the protection of S-nitrosylation on IKKβ in DSS-induced colitis for 6 days by curcumin caused the repression of IκB phosphorylation and NF-κB activation. In conclusion, this study verified that curcumin-mediated S-nitrosylation may be as an important regulator for anti-inflammation in DSS-induced colitis of mice.     

Tacrolimus ameliorates dextran sulfate sodium-induced colitis in mice: implication of interferon-γ and interleukin-1β suppression

We investigated the effect of tacrolimus, a calcineurin inhibitor, on dextran sulfate sodium (DSS)-induced colitis. After inducing colitis in C57BL/6 mice by administering DSS solution as drinking water for 7 d, the animals were treated with tacrolimus. Severity of colonic inflammation was evaluated based on colon weight per unit length. Levels of cytokines (interferon (IFN)-γ, interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-12, and tumor necrosis factor (TNF)-α) released from isolated inflamed colons of mice treated with tacrolimus or vehicle were also measured. Treatment with tacrolimus for 14 d reduced the colon weight per unit length and suppressed the release of IFN-γ and IL-1β, but not other cytokines, in inflamed colons of colitic mice compared with vehicle-treated mice. A positive correlation was noted between colon weight per unit length and released level of IFN-γ or IL-1β. The release of IFN-γ and IL-1β was also suppressed after single dosing with tacrolimus to colitic mice. Taken together, these results suggested that tacrolimus ameliorated DSS-induced colitis by suppressing release of IFN-γ and IL-1β from inflamed colon.     

Ginsenoside Rg3 ameliorates lipopolysaccharide-induced acute lung injury in mice through inactivating the nuclear factor-κB (NF-κB) signaling pathway

Ginsenoside Rg3 (GRg3), one of the major active saponins isolated from ginseng (the root of Panax ginseng C.A. Meyer, Araliaceae), has been reported with many health benefits. Currently, the protective effect of GRg3 on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice was investigated. The results indicated that GRg3 treatment could greatly attenuate LPS-induced histopathological alterations in the lung in a concentration-dependent manner. LPS-induced increase of lung wet-to-dry weight ratio (W/D ratio) was also dose-dependently reduced by GRg3 treatment. LPS-induced increases of the total cells, neutrophils and macrophages in the bronchoalveolar lavage fluids (BALFs) were significantly inhibited by GRg3 treatment in a dose-dependent fashion. The levels of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6 in BALFs increased after LPS-induced ALI, which was inhibited by GRg3. Western blot results showed that during ALI LPS activated NF-κB pathway in the lung tissues by upregulating NF-κB p65 phosphorylation and its downstream COX-2 expression; however, these effects of LPS were inhibited by GRg3 treatment. Taken together, these findings in present study suggested that GRg3 provided protective effects against LPS-induced ALI in animal model and might harbor the potential to be considered as drug for the treatment of ALI in clinic.     

Periplaneta americana extract ameliorates dextran sulfate sodium-induced ulcerative colitis via immunoregulatory and PI3K/AKT/NF-κB signaling pathways

Inflammopharmacology - Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) with a low cure rate. Periplaneta americana is a traditional American Cockroach and reportedly has...     

Parthenolide,an NF-κB inhibitor,alleviates peritoneal fibrosis by suppressing the TGF-β/Smad pathway

Transforming growth factor (TGF)-β/Smad signalling plays a central role in the pathogenesis of peritoneal fibrosis related to peritoneal dialysis (PD). Parthenolide (PTL), a naturally occurring phytochemical, is isolated from the shoots of feverfew (Tanacetum parthenium) and displays analgesia, anti-inflammation and anticancer activities. In this study, we examined the therapeutic potential of PTL on PD-related peritoneal fibrosis induced by daily intraperitoneal injection of 4.25% dextrose-containing PD fluid (PDF) in vivo and TGF-β1-induced epithelial-mesenchymal transition (EMT) in vitro. PTL was administered daily before PDF injection or after 14 days of PDF injection. Both PTL treatments showed a protective effect on peritoneal fibrosis and prevented peritoneal dysfunction. Similarly, PTL suppressed the expression of fibrotic markers (fibronectin and collagen I) and restored the expression of the epithelial marker (E-cadherin) in TGF-β1-treated HMrSV5 cells. Furthermore, PTL inhibited TGF-β1-induced Smad2 and Smad3 phosphorylation and nuclear translocation but did not influence Smad1/5/9 phosphorylation or activate other downstream signalling pathways of TGF-β1, including AKT, extracellular signal-regulated kinase (ERK) or p38. In conclusion, PTL treatment may represent an effective and novel therapy for PD-associated peritoneal fibrosis by suppressing the TGF-β/Smad pathway.     

Quercetin ameliorates imiquimod-induced psoriasis-like skin inflammation in mice via the NF-κB pathway

Quercetin (QC) is a dietary flavonoid abundant in many natural plants. A series of studies have shown that it has been shown to exhibit several biological properties, including anti-inflammatory, anti-oxidant, cardio-protective, vasodilatory, liver-protective and anti-cancer activities. However, so far the possible therapeutic effect of QC on psoriasis has not been reported. The present study was undertaken to evaluate the potential beneficial effect of QC in psoriasis using a generated imiquimod (IMQ)-induced psoriasis-like mouse model, and to further elucidate its underlying mechanisms of action. Effects of QC on PASI scores, back temperature, histopathological changes, oxidative/anti-oxidative indexes, pro-inflammatory cytokines and NF-κB pathway in IMQ-induced mice were investigated. Our results showed that QC could significantly reduce the PASI scores, decrease the temperature of the psoriasis-like lesions, and ameliorate the deteriorating histopathology in IMQ-induced mice. Moreover, QC effectively attenuated levels of TNF-α, IL-6 and IL-17 in serum, increased activities of GSH, CAT and SOD, and decreased the accumulation of MDA in skin tissue induced by IMQ in mice. The mechanism may be associated with the down-regulation of NF-κB, IKKα, NIK and RelB expression and up-regulation of TRAF3, which were critically involved in the non-canonical NF-κB pathway. In conclusion, our present study demonstrated that QC had appreciable anti-psoriasis effects in IMQ-induced mice, and the underlying mechanism may involve the improvement of antioxidant and anti-inflammatory status and inhibition on the activation of the NF-κB signaling. Hence, QC, a naturally occurring flavone with potent anti-psoriatic effects, has the potential for further development as a candidate for psoriasis treatment.     

Genistein potentiates the anti-cancer effects of gemcitabine in human osteosarcoma via the downregulation of Akt and nuclear factor-κB pathway

Genistein, a nontoxic flavonoid compound, has potent antitumor activity in various cancer cells. In the present study, we investigated whether genistein could be employed as a novel strategy to enhance the anti-tumor activity of gemcitabine using human osteosarcoma MNNG/HOS tumor model. In vitro, by MTT, electron microscopy, immunobloting and qRT-PCR assay, we found that the combination treatment of genistein and gemcitabine resulted in stronger growth inhibition and apoptosis induction through the downregulation of NF-κB activity and Akt activation in osteosarcoma cells. Moreover, the synergetic effects were observed when genistein was replaced by PI3K/Akt-pathway inhibitor (LY-294002) or NF-κB inhibitor (BAY11-7082). In vivo, the combination therapy augmented tumor growth inhibition through the down-regulation of NF-κB activity and Akt activation in xenografts. Taken together, these results provide in vitro and in vivo evidence that genistein abrogates gemcitabine-induced activation of NF-κB and increases the chemosensitization of osteosarcoma to gemcitabine. Combination therapy appears as a rational and novel approach for osteosarcoma treatment.     

An exogenous hydrogen sulphide donor, NaHS, inhibits the nuclear factor κB inhibitor kinase/nuclear factor κb inhibitor/nuclear factor-κB signaling pathway and exerts cardioprotective effects in a rat hemorrhagic shock model

Hemorrhagic shock (HS) is a common condition and leading cause of death in trauma patients universally. Severe inflammatory responses during HS finally lead to multiple-organ failure. Hydrogen sulphide (H?S) is increasingly recognized as an important signaling molecule with various protective effects. In the present study, we investigated the antiinflammatory and cardioprotective effects of an exogenous H?S donor, sodium hydrosulfide (NaHS), in an HS rat model. Male Sprague-Dawley rats were randomly divided into the sham-operated, sham-operated treated with NaHS (28?μmol/kg, intraperitoneally (i.p.)), HS, and HS treated with NaHS (28?μmol/kg, i.p.) groups. The HS groups were subjected to mimicked HS for 1?h and then treated with NaHS or left untreated. The rats were then resuscitated with Ringer lactate solution for 1?h. Myocardial enzymes and inflammatory cytokines were evaluated. Morphologic changes in cardiac tissue and ultrastructural injury were also analyzed. HS resulted in significant hemodynamic deterioration and increased myocardial enzyme and inflammatory cytokine levels. Intraperitoneal administration of NaHS significantly prevented hemodynamic deterioration and decreased the elevation of myocardial enzymes. NaHS also inhibited the nuclear factor κB inhibitor kinase (IKK)/nuclear factor κB inhibitor (IκB)/nuclear factor κB (NF-κB) signaling pathway. The results suggest that NaHS exerts cardioprotective effects against HS. The protective effects of NaHS may occur via down-regulation of the IKK/IκB/NF-κB signaling pathway.     

Dapagliflozin,an SGLT2 inhibitor,ameliorates acetic acid-induced colitis in rats by targeting NFκB/AMPK/NLRP3 axis

Inflammopharmacology - The development of effective treatment strategies has been hindered by the complex pathogenesis of ulcerative colitis (UC). UC patients treated with current therapeutic...     

Pharmacokinetics of omeprazole in rats with dextran sulfate sodium–induced ulcerative colitis

Omeprazole is a commonly used drug in patients with ulcerative colitis (UC). This study investigated the pharmacokinetics of omeprazole in rats with UC induced by dextran sulfate sodium (DSS). The pharmacokinetics of intravenously administered omeprazole (20 mg/kg) was investigated in normal and UC rats using LC-MS/MS. The formation of 5-OH omeprazole, a main metabolite of omeprazole, in rat liver microsomes (RLMs) from normal and UC rats was compared. The protein levels of CYP1A2, CYP2D1, and CYP3A1 in the liver were measured by Western blot. Compared with normal rats, UC rats had increased plasma concentrations of omeprazole, resulting in an increased AUC_0–240 min and decreased CL. DSS treatment decreased the formation rate of 5-OH omeprazole in RLMs but did not change the affinity of the enzymes. The V_max and CL_int of RLMs from UC rats were 62% and 48% those of RLMs from normal rats, respectively. The hepatic CYP1A2 and CYP3A1 protein levels in UC rats were 42.6 and 45.2% lower than those in normal rats, respectively; however, the protein levels of CYP2D1 in the two groups were similar. The activity and expression of some hepatic CYP450 isoforms were decreased by UC, leading to changes in the pharmacokinetics of omeprazole.     

Role of nuclear factor-κB in a rat model of vascular injury

In this study we have investigated the relationship between neointima formation and NF-kappaB activation in a model of endothelial denudation of rat carotid artery (balloon angioplasty) using the antioxidant pyrrolidine dithiocarbamate as inhibitor of NF-kappaB activation. Furthermore, we have correlated NF-kappaB activation to the expression of inducible isoforms of both nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in injured carotids. In control group a significant proliferation of neointima was observed 14 days after balloon angioplasty, which was correlated to an increase of NF-kappaB/DNA binding activity as well as p50/p65 nuclear levels compared to those observed in the carotids from naive or sham-operated rats. Furthermore, NF-kappaB activation was correlated to increased iNOS and COX-2, but not beta-actin, protein expression. Treatment of rats for 14 days with the antioxidant agent pyrrolidine dithiocarbamate (50, 100, 200 mg/kg per os and day) caused a significant inhibition of all the parameters assayed, except beta-actin protein expression. These results indicate that prevention of NF-kappaB activation may lead to the inhibition of neointima formation and suggest that antioxidant agents may have therapeutic relevance for the prevention of human restenosis.     

Macrophage activation by polysaccharides from Atractylodes macrocephala Koidz through the nuclear factor-κB pathway

Abstract

Context: Atractylodes macrocephala Koidz is a traditional herb. Atractylodes macrocephalaon polysaccharides (AMP) have been found to enhance immunity and improve heart function. However, the mechanisms of the immunomodulatory effect have not been investigated.

Objective: We examined whether AMP activated macrophages and explored the mechanisms of activation.

Materials and methods: AMP was prepared and evaluated its immunomodulatory activity (25, 50, 100, and 200?μg/mL) by detecting the phagocytosis and the production of tumor necrosis factor-α (TNF-α), IFN-γ, and nitric oxide (NO) in RAW264.7 macrophages. Furthermore, the role of nuclear factor-κB (NF-κB) pathway was examined in regulating TNF-α and NO production.

Results: The phagocytosis of macrophages was enhanced by AMP in a dose-dependent manner and the maximal phagocytosis of macrophages occurred at concentrations of 100 and 200?μg/mL. NO, TNF-α, and IFN-γ release was also found to be dose dependent by increasing concentrations of AMP and reached the peak at a concentration of 200?μg/mL. In addition, AMP induced inhibitor kappaB (IκB) degradation and the activation of NF-κB by p65 nuclear translocation, and then the activation of NF-κB in nucleus peaked at a concentration of 200?μg/mL. Besides, NF-κB-specific inhibitor pyrrolidine dithiocarbamate (PDTC) decreased AMP-induced NO and TNF-α production.

Discussion and conclusion: These data suggest that AMP may modulate macrophage activities by stimulating NF-κB or activating NF-κB-dependent mechanisms.     

Antrodia camphorata suppresses lipopolysaccharide-induced nuclear factor-κB activation in transgenic mice evaluated by bioluminescence imaging

In an earlier study, we found that Antrodia camphorata inhibited the production of lipopolysaccharide (LPS)-induced cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 by blocking nuclear factor-κB (NF-κB) activation in cultured RAW 264.7 macrophages. This study was aimed at evaluating the inhibitory effects of the fermented culture broth of A. camphorata in terms of LPS-induced NF-κB activation in transgenic mice by using a non-invasive, real-time NF-κB bioluminescence imaging technique. Transgenic mice carrying the luciferase gene under the control of NF-κB were given A. camphorata (570 mg/kg, p.o.) for three consecutive days and then injected with LPS (4 mg/kg, i.p.). In vivo imaging showed that treatment with LPS increased the luminescent signal, whereas A. camphorata suppressed the LPS-induced inflammatory response significantly. Ex vivo imaging showed that A. camphorata suppressed LPS-induced NF-κB activity in the small intestine, mesenteric lymph nodes, liver, spleen, and kidney. Immunohistochemical staining revealed that A. camphorata suppressed production of the LPS-induced tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and NF-κB p65 subunit in these organs. Furthermore, A. camphorata attenuated the productions of LPS-induced TNF-α and IL-1β in serum from transgenic mice. We report the first confirmation of the anti-inflammatory action in vivo of this potentially beneficial mushroom.