Gigantol isolated from the whole plants of Cymbidium goeringii inhibits the LPS-induced iNOS and COX-2 expression via NF-kappaB inactivation in RAW 264.7 macrophages cells

During our efforts to find bioactive natural products with anti-inflammatory activity, we isolated gigantol from the whole plants of Cymbidium goeringii (Orchidaceae) by activity-guided chromatographic fractionation. Gigantol was found to have potent inhibitory effects on LPS-induced nitric oxide (NO) and prostaglandin E (2) (PGE (2)) production in RAW 264.7 cells. Consistent with these findings, gigantol suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein and mRNA levels in RAW 264.7 cells in a concentration-dependent manner. Our data also indicate that gigantol is a potent inhibitor of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) release and influenced the mRNA expression levels of these cytokines in a dose-dependent manner. Furthermore, a reporter gene assay for nuclear factor kappa B (NF-kappaB) and an electromobility shift assay (EMSA) demonstrated that gigantol effectively inhibited the activation of NF-kappaB, which is necessary for the expression of iNOS, COX-2, TNF-alpha, IL-1beta and IL-6. Thus, our studies suggest that gigantol inhibits LPS-induced iNOS and COX-2 expression by blocking NF- kappaB activation.     

Involvement of protein kinase C-gamma in IL-1beta-induced cyclooxygenase-2 expression in human pulmonary epithelial cells

The signaling pathway of protein kinase C (PKC) is known to play a role in mediating the action of various cytokines. Here we examined the signal transduction pathway of PKC activation and the role of PKC isoforms in interleukin-1beta (IL-1beta)-mediated cyclooxygenase-2 (COX-2) expression in human pulmonary epithelial cell line (A549). The tyrosine kinase inhibitors (genistein and tyrphostin AG126) and phosphatidylcholine-phospholipase C inhibitor (D-609) prevented IL-1beta-induced prostaglandin E(2) (PGE(2)) release and COX-2 expression, whereas U-73122 (a phosphatidylinositol-phospholipase C inhibitor) and propranolol (a phosphatidate phosphohydrolase inhibitor) had no effect. The PKC inhibitors (Go 6976 and Ro 31-8220) and NF-kappaB inhibitor, pyrrolidine dithiocarbamate, also attenuated IL-1beta-induced PGE(2) release and COX-2 expression. Western blot analysis using PKC isoenzyme-specific antibodies indicated that A549 cells expressed PKC-alpha, -gamma, -iota, -lambda, -zeta, and -micro. IL-1beta caused the translocation of PKC-gamma but not other isoforms from cytosol to the membrane fraction. Moreover, the translocation of PKC-gamma was inhibited by genistein or D-609, but not by U-73122. IL-1beta caused the translocation of p65 NF-kappaB from cytosol to the nucleus as well as the degradation of IkappaB-alpha in cytosol. Furthermore, the translocation of p65 NF-kappaB was inhibited by genistein, Go 6976, Ro 31-8220, or pyrrolidine dithiocarbamate. These results indicate that in human pulmonary epithelial cells, IL-1beta might activate phosphatidylcholine-phospholipase C through an upstream tyrosine phosphorylation to elicit PKC activation, which in turn initiates NF-kappaB activation, and finally induces COX-2 expression and PGE(2) release. Of the PKC isoforms present in A549 cells, only activation of PKC-gamma is involved in regulating IL-1beta-induced responses.     

Byakangelicol,isolated from Angelica dahurica,inhibits both the activity and induction of cyclooxygenase-2 in human pulmonary epithelial cells

We examined the inhibitory mechanism of byakangelicol, isolated from Angelica dahurica, on interleukin-1beta (IL-1beta)-induced cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) release in human pulmonary epithelial cell line (A549). Byakangelicol (10-50 microM) concentration-dependently attenuated IL-1beta-induced COX-2 expression and PGE2 release. The selective COX-2 inhibitor, NS-398 (0.01-1 microM), and byakangelicol (10-50 microM) both concentration-dependently inhibited the activity of the COX-2 enzyme. Byakangelicol, at a concentration up to 200 microM, did not affect the activity and expression of COX-1 enzyme. IL-1beta-induced p44/42 mitogen-activated protein kinase (MAPK) activation was inhibited by the MAPK/extracellular signal-regulated protein kinase (MEK) inhibitor, PD 98059 (30 microM), while byakangelicol (50 microM) had no effect. Treatment of cells with byakangelicol (50 microM) or pyrrolidine dithiocarbamate (PDTC; 50 microM) partially inhibited IL-1beta-induced degradation of IkappaB-alpha in the cytosol, translocation of p65 NF-kappaB from the cytosol to the nucleus and the NF-kappaB-specific DNA-protein complex formation. Taken together, we have demonstrated that byakangelicol inhibits IL-1beta-induced PGE2 release in A549 cells; this inhibition may be mediated by suppression of COX-2 expression and the activity of COX-2 enzyme. The inhibitory mechanism of byakangelicol on IL-1beta-induced COX-2 expression may be, at least in part, through suppression of NF-kappaB activity. Therefore, byakangelicol may have therapeutic potential as an anti-inflammatory drug on airway inflammation.     

Preliminary exploration on anti-inflammatory mechanism of Corilagin (beta-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-D-glucose) in vitro

Corilagin (beta-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-D-glucose) is a novel member of the tannin family which has been discovered from many medicinal plants and has been confirmed in many pharmacological activities. However, the purified Corilagin that was used in experiment is rare, and the anti-inflammatory mechanism of Corilagin has not been investigated clearly. This study is to explore the inner anti-inflammatory mechanism of Corilagin. Inflammatory cellular model was established by lipopolysaccharide (LPS) interfering on RAW264.7 cell line. Levels of TNF-alpha, IL-1beta, IL-6, NO and IL-10 in supernatant, mRNA expression of TNF-alpha, COX-2, iNOS and HO-1, protein expression of COX-2 and HO-1, translocation of NF-kappaB were assayed by ELISA or Griess method, real-time quantitative PCR, western blot and immunocytochemistry method, respectively. As a result, Corilagin could significantly reduce production of pro-inflammatory cytokines and mediators TNF-alpha, IL-1beta, IL-6, NO (iNOS) and COX-2 on both protein and gene level by blocking NF-kappaB nuclear translocation. Meanwhile Corilagin could notably promote release of anti-inflammatory factor HO-1 on both protein and gene level, but suppress the release of IL-10. In conclusion, the anti-inflammatory effects of Corilagin are attributed to the suppression of pro-inflammatory cytokines and mediators by blocking NF-kappaB activation. Corilagin also can promote HO-1 production to induce regression of inflammation but can inhibit IL-10 production like Dexamethasone. Corilagin possesses a potential anti-inflammatory effect by not only abating inflammatory impairment but also promoting regression of inflammation and has a good prospect to be used in many inflammation-related diseases.     

Sodium salicylate inhibits expression of COX-2 through suppression of ERK and subsequent NF-κB activation in Rat ventricular cardiomyocytes

The expression of cyclooxygenase-2 (COX-2) is a characteristic response to inflammation, which can be inhibited with sodium salicylate. IL-1beta and TNF-alpha can induce extracellular signal-regulated kinase (ERK), IKK, IkappaB degradation and NF-kappaB activation. Salicylate inhibited the IL-1beta and TNF-alpha-induced COX-2 expressions, regulated the activation of ERK, IKK and IkappaB degradation, and the subsequent activation of NF-kappaB, in neonatal rat ventricular cardiomyocytes. The inhibition of the ERK pathway, with a selective inhibitor, PD098059, blocked the expressions of IL-1beta and TNF-alpha-induced COX-2 and PGE2 release. The antioxidant, N-acetyl-cysteine, also reduced the glutathione or catalase- attenuated COX-2 expressions in IL-1beta and TNF-alpha-treated cells. This antioxidant also inhibited the activation of ERK and NF-kappaB in neonatal rat cardiomyocytes. In addition, IL-1beta and TNF-alpha stimulated the release of reactive oxygen species (ROS) in the cardiomyocytes. However, salicylate had no inhibitory effect on the release of ROS in the DCFDA assay. The results showed that salicylate inhibited the activation of ERK and IKK, IkappaB degradation and NF-kappaB activation, independently of the release of ROS, which suggested that salicylate exerts its anti-inflammatory action through the inhibition of ERK, IKK, IkappaB and NF-kappaB, and the resultant COX-2 expression pathway in neonatal rat ventricular cardiomyocytes.     

Styraxoside A isolated from the stem bark of Styrax japonica inhibits lipopolysaccharide-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 in RAW 264.7 cells by suppressing nuclear factor-kappa B activation

In the present study, the effects of terpenes (styraxosides A and B) and lignans (egonol, masutakeside I, and styraxlignolide A) isolated from the stem bark of Styrax japonica Sieb. et Zucc. (styracaceae) were evaluated on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by the RAW 264.7 macrophage cell line. Of the tested compounds, styraxoside A was found to most potently inhibit the productions of NO and PGE2, and also significantly reduced the release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta). Consistent with these observations, the protein expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and the mRNA expression levels of iNOS, COX-2, TNF-alpha and IL-1beta were found to be inhibited by styraxoside A in a concentration-dependent manner. Furthermore, styraxoside A inhibited the LPS-induced DNA binding activity of nuclear factor-kappaB (NF-kappaB). Taken together, our data indicate that styraxoside A inhibits LPS-induced iNOS, COX-2, TNF-alpha, and IL-1beta expressions through the down-regulation of NF-kappaB-DNA binding activity.     

Heterotrimeric G protein G alpha13-induced induction of cytokine mRNAs through two distinct pathways in cardiac fibroblasts

Overexpression of constitutively active (CA)-G alpha13 significantly increased the expression of interleukin (IL)-1beta and IL-6 mRNAs and proteins in rat cardiac fibroblasts. IL-1beta mRNA induction by CA-G alpha13 was suppressed by diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, but not by BAPTA-AM, an intracellular Ca2+ chelator. In contrast, IL-6 mRNA induction by CA-G alpha13 was suppressed by BAPTA-AM but not by DPI. However, both IL-1beta and IL-6 mRNA induction was suppressed by nuclear factor kappaB (NF-kappaB) inhibitors. The CA-G alpha13-induced NF-kappaB activation was suppressed by DPI and BAPTA-AM, but not C3 toxin and the Rho-kinase inhibitor Y27632. IL-6 mRNA induction by CA-G alpha13 was suppressed by SK&F96365 (1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride), an inhibitor of receptor-activated nonselective cation channels, and the expression of CA-G alpha13 increased basal Ca2+ influx. These results suggest that G alpha13 regulates IL-1beta mRNA induction through the reactive oxygen species-NF-kappaB pathway, while it regulates IL-6 mRNA induction through the Ca2+-NF-kappaB pathway.     

Inhibition of COX-2 activity and proinflammatory cytokines (TNF-α and IL-1β) production by water-soluble sub-fractionated parts from bee (<Emphasis Type="Italic">Apis mellifera</Emphasis>) venom

Bee venom is used as a traditional medicine for treatment of arthritis. The anti-inflammatory activity of the n-hexane, ethyl acetate, and aqueous partitions from bee venom (Apis mellifera) was studied using cyclooxygenase (COX) activity and pro-inflammatory cytokines (TNF-alpha and IL-1beta) production, in vitro. COX-2 is involved in the production of prostaglandins that mediate pain and support the inflammatory process. The aqueous partition of bee venom showed strong dose-dependent inhibitory effects on COX-2 activity (IC50 = 13.1 microg/mL), but did not inhibit COX-1 activity. The aqueous partition was subfractionated into three parts by molecular weight differences, namely, B-F1 (above 20 KDa), B-F2 (between 10 KDa and 20 KDa) and B-F3 (below 10 KDa). B-F2 and B-F3 strongly inhibited COX-2 activity and COX-2 mRNA expression in a dose-dependent manner, without revealing cytotoxic effects. TNF-alpha and IL-1beta, are potent pro-inflammatory cytokines and are early indicators of the inflammatory process. We also investigated the effects of three subfractions on TNF-alpha and IL-1beta production using ELISA method. All three subfractions, B-F1, B-F2 and B-F3, inhibited TNF-alpha and IL-1beta production. These results suggest the pharmacological activities of bee venom on anti-inflammatory process include the inhibition of COX-2 expression and the blocking of pro-inflammatory cytokines (TNF-alpha, and IL-1beta) production.     

Inhibition of LPS-induced iNOS, COX-2 and cytokines expression by poncirin through the NF-kappaB inactivation in RAW 264.7 macrophage cells

We previously reported that poncirin, a flavanone glycoside isolated from the EtOAc extract of the dried immature fruits of Poncirus trifoliata, is an anti-inflammatory compound that inhibits PGE(2) and IL-6 production. The present work was undertaken to investigate the molecular actions of poncirin in RAW 264.7 macrophage cell line. Poncirin reduced lipopolysaccharide (LPS)-induced protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and the mRNA expressions of iNOS, COX-2, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in a concentration-dependent manner, as determined by Western blotting and RT-PCR, respectively. Furthermore, poncirin inhibited the LPS-induced DNA binding activity of nuclear factor-kappaB (NF-kappaB). Moreover, this effect was accompanied by a parallel reduction in IkappaB-alpha degradation and phosphorylation that in by nuclear translocations of p50 and p65 NF-kappaB subunits. Taken together, our data indicate that anti-inflammatory properties of poncirin might be the result from the inhibition iNOS, COX-2, TNF-alpha and IL-6 expression via the down-regulation of NF-kappaB binding activity.     

Suppression of NF-kappaB activation by curcumin leads to inhibition of expression of cyclo-oxygenase-2 and matrix metalloproteinase-9 in human articular chondrocytes: Implications for the treatment of osteoarthritis

Pro-inflammatory cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) play a key role in the pathogenesis of osteoarthritis (OA). Anti-inflammatory agents capable of suppressing the production and catabolic actions of these cytokines may have therapeutic potential in the treatment of OA and a range of other osteoarticular disorders. The purpose of this study was to examine the effects of curcumin (diferuloylmethane), a pharmacologically safe phytochemical agent with potent anti-inflammatory properties on IL-1beta and TNF-alpha signalling pathways in human articular chondrocytes maintained in vitro. The effects of curcumin were studied in cultures of human articular chondrocytes treated with IL-1beta and TNF-alpha for up to 72h. Expression of collagen type II, integrin beta1, cyclo-oxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9) was monitored by western blotting. The effects of curcumin on the expression, phosphorylation and nuclear translocation of protein components of the NF-kappaB system were studied by western blotting and immunofluorescence, respectively. Treatment of chondrocytes with curcumin suppressed IL-1beta-induced NF-kappaB activation via inhibition of IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation and p65 nuclear translocation. Curcumin inhibited the IL-1beta-induced stimulation of up-stream protein kinase B Akt. These events correlated with down-regulation of NF-kappaB targets including COX-2 and MMP-9. Similar results were obtained in chondrocytes stimulated with TNF-alpha. Curcumin also reversed the IL-1beta-induced down-regulation of collagen type II and beta1-integrin receptor expression. These results indicate that curcumin has nutritional potential as a naturally occurring anti-inflammatory agent for treating OA through suppression of NF-kappaB mediated IL-1beta/TNF-alpha catabolic signalling pathways in chondrocytes.     

Inhibition of LPS-induced NO and PGE2 production by asiatic acid via NF-kappa B inactivation in RAW 264.7 macrophages: possible involvement of the IKK and MAPK pathways

In the present study, we investigated the effect of asiatic acid (the aglycon of asiaticoside) and asiaticoside isolated from the leaves of Centella asiatica (Umbelliferae) on LPS-induced NO and PGE(2) production in RAW 264.7 macrophage cells. Asiatic acid more potently inhibited LPS-induced NO and PGE(2) production than asiaticoside. Consistent with these observations, the protein and mRNA expression levels of inducible iNOS and COX-2 enzymes were inhibited by asiatic acid in a concentration-dependent manner. In addition, asiatic acid dose-dependently reduced the production of IL-6, IL-1 beta and TNF-alpha in LPS-stimulated RAW 264.7 macrophage cells. Furthermore, asiatic acid inhibited the NF-kappaB activation induced by LPS, and this was associated with the abrogation of I kappa B-alpha degradation and with subsequent decreases in nuclear p65 and p50 protein levels. Moreover, the phosphorylations of IKK, p38, ERK1/2, and JNK in LPS-stimulated RAW 264.7 cells were suppressed by asiatic acid in a dose-dependent manner. These results suggest that the anti-inflammatory properties of asiatic acid might be the results from the inhibition of iNOS, COX-2, IL-6, IL-1 beta, and TNF-alpha expressions through the down-regulation of NF-kappaB activation via suppression of IKK and MAP kinase (p38, ERK1/2, and JNK) phosphorylation in RAW 264.7 cells.     

Interleukin-1beta-induced mucin production in human airway epithelium is mediated by cyclooxygenase-2, prostaglandin E2 receptors, and cyclic AMP-protein kinase A signaling

We reported recently that interleukin (IL)-1beta exposure resulted in a prolonged increase in MUC5AC mucin production in normal, well differentiated, human tracheobronchial epithelial (NHTBE) cell cultures, without significantly increasing MUC5AC mRNA (Am J Physiol 286:L320-L330, 2004). The goal of the present study was to elucidate the signaling pathways involved in IL-1beta-induced MUC5AC production. We found that IL-1beta increased cyclooxygenase-2 (COX-2) mRNA expression and prostaglandin (PG) E(2) production and that the COX-2 inhibitor celecoxib suppressed IL-1beta-induced MUC5AC production. Addition of exogenous PGE(2) to NHTBE cultures also increased MUC5AC production and IL-1beta-induced Muc5ac hypersecretion in tracheas from wild-type but not from COX-2-/- mice. NHTBE cells expressed all four E-prostanoid (EP) receptor subtypes and misoprostol, an EP2 and EP4 agonist, increased MUC5AC production, whereas sulprostone, an EP1 and EP3 agonist, did not. Furthermore, specific protein kinase A (PKA) inhibitors blocked IL-1beta and PGE(2)-induced MUC5AC production. However, neither inhibition of epidermal growth factor receptor (EGFR) activation with the tyrosine kinase inhibitor 4-(3-chloroanilino)-6,7-dimethoxyquinazoline HCl (AG-1478) or EGFR blocking antibody nor inhibition of extracellular signal-regulated kinase/P-38 mitogen activated protein kinases with specific inhibitors blocked IL-1beta stimulation of MUC5AC mucin production. We also observed that tumor necrosis factor (TNF)-alpha, platelet activating factor (PAF), and lipopolysaccharide (LPS) induced COX-2 and increased MUC5AC production that was blocked by celecoxib, suggesting a common signaling pathway of inflammatory mediator-induced MUC5AC production in NHTBE cells. We conclude that the induction of MUC5AC by IL-1beta, TNF-alpha, PAF, and LPS involves COX-2- generated PGE(2), activation of EP2 and/or EP4 receptor(s), and cAMP-PKA-mediated signaling.     

羟基红花黄色素A对脑缺血大鼠皮层炎症信号转导途径相关因子的抑制作用

羟基红花黄色素A(hydroxysafflor yellow A，HSYA)是红花中的单体有效成分。本研究采用线栓法制备大鼠永久性脑缺血模型，观察HSYA对永久性脑缺血大鼠炎症信号转导途径相关因子的抑制作用。于缺血后3、 6、 12和24 h取大脑皮层。Western blotting 检测细胞核及胞浆核转录因子κB(NF-κB) p65及胞浆磷酸化IκB-α(pIκB-α)蛋白水平表达；Trans AM试剂盒检测NF-κB DNA结合活性；RT-PCR检测炎性因子TNF-α、 IL-1β、 IL-6和IL-10转录水平表达。结果表明，大鼠脑缺血后多次静脉注射HSYA(10 mg·kg^-1)，能显著抑制p65核转位以及IκB-α的磷酸化，降低NF-κB DNA结合活性，并降低促炎因子TNF-α、 IL-1β和IL-6 mRNA表达，升高抗炎因子IL-10 mRNA表达水平。提示HSYA的抗脑缺血作用可能与其抑制炎症信号途径中NF-κB激活及炎性因子转录水平表达有关。