A limited series of synthetic tetrahydroisoquinoline alkaloids reduce inflammatory gene iNOS via inhibition of p-STAT-1 and suppress HMGB1 secretion in LPS-treated mice lung tissue

Tetrahydroisoquinoline alkaloids (THIs) have shown to increase survival and beneficial effect on animal model of sepsis, partly due to heme oxygenase-1 (HO-1) induction. Here, we aimed to compare a limited series of synthesized THIs on HO-1 induction and inhibitory effect of iNOS and COX-2 expression in lipopolysaccharide (LPS)-activated RAW264.7 cells. To the end, most promising compound (THI-61) was tested whether this compound reduces iNOS protein expression and inflammatory markers (HMGB1, TNF-α) in LPS-treated mice lung tissue. The results indicated that N-carbonyl substituted THI seem to affect HO-1 induction depending on which functional group is attached to C1 position. All compounds that reduce LPS-activated NF-κB-luciferase activity showed to preferential inhibition of iNOS/NO but not COX-2/PGE₂ that was partly related to inhibition of STAT-1 phosphorylation. In particular, THI-61 induced translocation of Nrf2 from cytosol into the nucleus by an increased Nrf2-ARE binding activity, and reduced IL-1β production in LPS-activated RAW264.7 cells. The reduced expression of iNOS/NO by THI-61 was reversed by siHO-1RNA-transfection. In LPS-treated mice, THI-61 significantly reduced iNOS protein in lung tissues, and HMGB1 and TNF-α levels in the BALF. We concluded that 1) lipophilic moiety of 1C substituent is much more important in N-carbonyl substituted THI for induction of HO-1, 2) newly synthesized THI-61 may be beneficial for treatment of lung injury.     

4,7-Dimethoxy-5-methyl-1,3-benzodioxole from Antrodia camphorata inhibits LPS-induced inflammation via suppression of NF-κB and induction HO-1 in RAW264.7 cells

Several benzenoid compounds have been isolated from Antrodia camphorata are known to have excellent anti-inflammatory activity. In this study, we investigated the anti-inflammatory potential of 4,7-dimethoxy-5-methyl-1,3-benzodioxole (DMB), one of the major benzenoid compounds isolated from the mycelia of A. camphorata. DMB significantly decreased the LPS-induced production of pro-inflammatory molecules, such as nitric oxide (NO), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in RAW264.7 cells. In addition, DMB suppressed the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose dependent manner. Moreover, DMB significantly suppressed LPS-induced nuclear translocation of nuclear factor-κB (NF-κB), and this inhibition was found to be associated with decreases in the phosphorylation and degradation of its inhibitor, inhibitory κB-α (IκB-α). Moreover, we found that DMB markedly inhibited the protein expression level of Toll-like receptor 4 (TLR4). Furthermore, treatment with DMB significantly increased hemoxygenase-1 (HO-1) expression in RAW264.7 cells, which is further confirmed by hemin, a HO-1 enhancer, significantly attenuated the LPS-induced pro-inflammatory molecules and iNOS and TLR4 protein levels. Taken together, the present study suggests that DMB may have therapeutic potential for the treatment of inflammatory diseases.     

Asperlin from the marine-derived fungus Aspergillus sp. SF-5044 exerts anti-inflammatory effects through heme oxygenase-1 expression in murine macrophages

Asperlin is a fungal metabolite isolated from Aspergillus sp. SF-5044. In the present study, we isolated asperlin from the marine-derived fungus Aspergillus sp. SF-5044 and demonstrated that it inhibited inducible nitric oxide synthase (iNOS) expression, reduced iNOS-derived NO, suppressed cyclooxygenase (COX)-2 expression, and reduced COX-derived prostaglandin (PG) E? production in lipopolysaccharide (LPS)-stimulated RAW264.7 and murine peritoneal macrophages. Similarly, asperlin reduced the production of tumor necrosis factor (TNF)-α and interleukin (IL)-1β. In addition, asperlin inhibited the phosphorylation and degradation of IκB-α, as well as the nuclear translocation of p65 caused by the stimulation of LPS in RAW264.7 macrophages. Furthermore, asperlin induced heme oxygenase (HO)-1 expression through nuclear translocation of nuclear factor E2-related factor 2 and increased HO activity in RAW264.7 macrophages. The effects of asperlin on the LPS-induced expression of iNOS and COX-2 and production of NO, PGE?, TNF-α, and IL-1β were partially reversed by a HO-1 inhibitor, tin protoporphyrin. These findings suggest that asperlin-induced HO-1 expression plays a role in the anti-inflammatory effects of asperlin in macrophages.     

穿琥宁抗炎作用的血红素加氧酶-1的信号转导机制

目的初步探讨穿琥宁抗炎作用的信号转导机制。方法用WST-8细胞计数试剂盒检测穿琥宁的细胞毒性;用IN Cell Analyzer 2000活细胞成像系统及组成型增强表达绿色荧光蛋白偶联NF-κBP65(EGFP-NF-κBP65)融合蛋白的CHO细胞和EGFP偶联促分裂原活化蛋白激酶APk2(EGFP-MAPK-APk2)融合蛋白的BHK细胞观察穿琥宁对白细胞介素1β(IL-1β)或肿瘤坏死因子α(TNF-α)诱导NF-κBP65核转位及脂多糖(LPS)诱导的P38MAPK下游分子MAPK-APk2核转位的影响;Western印迹法检测穿琥宁和血红素加氧酶-1(HO-1)特异性抑制剂锌原卟啉(ZnPP)对RAW264.7细胞HO-1、诱导型一氧化氮合酶(iNOS)和环氧化酶2(COX-2)表达的影响;Griess反应和ELISA法测定穿琥宁对RAW264.7细胞一氧化氮(NO)和前列腺素E2(PGE2)生成的影响。结果穿琥宁3～100μmol·L-1作用24 h对RAW264.7细胞无细胞毒性。穿琥宁不能抑制由IL-1β诱导的NF-κBP65核转位和LPS诱导的MAPK-APk2核转位,对TNF-α诱导的NF-κBP65核转位有较弱的抑制作用,抑制率为20%,无明显浓度效应关系。穿琥宁3,10,30和100μmol·L-1作用4 h能诱导RAW264.7细胞HO-1表达,穿琥宁100μmol· L-1作用6 h显著抑制IL-1β诱导的COX-2表达和PGE2产生,作用12 h抑制iNOS表达和NO产生。HO-1活性抑制剂ZnPP能部分逆转穿琥宁的上述作用。结论穿琥宁的抗炎作用可能主要通过HO-1信号转导,继而抑制iNOS和COX-2的表达及NO和PGE2的产生。对NF-κB信号传导系统的调节作用尚不清楚。     

Anti-inflammatory activity of Angelica dahurica ethanolic extract on RAW264.7 cells via upregulation of heme oxygenase-1

In this study, we analyzed the anti-inflammatory effects of Angelica dahurica Bentham et Hooker ethanolic extract (ADEE) on RAW264.7 cells, to understand the mechanism underlying its observed effects. ADEE inhibited cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, leading to the suppression of COX-2-derived prostaglandin E₂ and iNOS-derived production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. These inhibitory effects of ADEE were accompanied by the reduced production of tumor necrosis factor α and interleukin (IL)-6. ADEE also inhibited nuclear factor κB (NFκB) translocation to the nucleus by interrupting inhibitor kappa Bα (IκBα) degradation. ADEE upregulated heme oxygenase 1 expression, and treatment with tin protoporphyrin IX (SnPP), a selective inhibitor of HO-1, reversed the LPS-induced generation of proinflammatory cytokines. ADEE also induced IL-4 and IL-5 expression in concanavalin-A-stimulated splenocytes. These results suggest that ADEE has anti-inflammatory activity, which acts via the suppression of the NF-κB pathway.     

Rheosmin,a naturally occurring phenolic compound inhibits LPS-induced iNOS and COX-2 expression in RAW264.7 cells by blocking NF-κB activation pathway

Inflammation is part of the host defense mechanism against harmful matters and injury; however, aberrant inflammation is associated to the development of chronic disease such as cancer. Raspberry ketone is a natural phenolic compound. It is used in perfumery, in cosmetics, and as a food additive to impart a fruity odor. In this study, we evaluated whether rheosmin, a phenolic compound isolated from pine needles regulates the expression of iNOS and COX-2 protein in LPS-stimulated RAW264.7 cells. Rheosmin dose-dependently inhibited NO and PGE₂ production and also blocked LPS-induced iNOS and COX-2 expression. Rheosmin potently inhibited the translocation of NF-κB p65 into the nucleus by IκB degradation following IκB-α phosphorylation. This result shows that rheosmin inhibits NF-κB activation. In conclusion, our results suggest that rheosmin inhibits LPS-induced iNOS and COX-2 expression in RAW264.7 cells by blocking NF-κB activation pathway.     

Pro-inflammatory effects of commercial alpha-lactalbumin on RAW 264.7 macrophages is due to endotoxin contamination

This study investigated the effects of alpha-lactalbumin (α-LA) on cellular signaling molecules associated with inflammatory responses in RAW 264.7 macrophages. The results indicated that commercial α-LA could increase prostaglandin E₂ (PGE₂) and the expression of COX-2 via increased phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK) and jun N-terminal kinase (JNK), and increase nitric oxide (NO) and the expression of iNOS via the activation of ERK1/2 and JNK. Furthermore, commercial α-LA could increase nuclear translocation of p65 nuclear factor-kappa B (p65 NF-κB) through stimulation on inhibitor kappa B-alpha (IκB-α) degradation. Since endotoxin also has these effects, we assayed the content of endotoxin in the commercial α-LA. We found to our surprise that endotoxin was there and that α-LA-induced NO and PGE₂ production could be suppressed by polymyxin B, a specific inhibitor of endotoxin. Thus, the pro-inflammatory effects of commercial α-LA might be caused by endotoxin contamination through activation and expression of iNOS and COX-2 which were upregulated by MAPKs or nuclear translocation of p65 NF-κB in RAW 264.7 cells. It is therefore crucial to assess the possibility of endotoxin contamination within any biological product being studied for immune augmenting activities before a meaning result can be obtained.     

Hydrangenol inhibits lipopolysaccharide-induced nitric oxide production in BV2 microglial cells by suppressing the NF-κB pathway and activating the Nrf2-mediated HO-1 pathway

We previously demonstrated the anti-inflammatory effect of water extract of Hydrangea macrophylla in lipopolysaccharide (LPS)-stimulated macrophage cells. Here, we investigated whether hydrangenol, a bioactive component of H. macrophylla, attenuates the expression of nitric oxide (NO) and its associated gene, inducible NO synthase (iNOS), in LPS-stimulated BV2 microglial cells. Our data showed that low dosages of hydrangenol inhibited LPS-stimulated NO release and iNOS expression without any accompanying cytotoxicity. Hydrangenol also suppressed LPS-induced nuclear translocation of nuclear factor-κB (NF-κB) subunits, consequently inhibiting DNA-binding activity of NF-κB. Additionally, the NF-κB inhibitors, pyrrolidine dithiocarbamate (PDTC) and PS-1145, significantly attenuated LPS-induced iNOS expression, indicating that hydrangenol-induced NF-κB inhibition might be a key regulator of iNOS expression. Furthermore, our data showed that hydrangenol suppresses NO production by inducing heme oxygenase-1 (HO-1). The presence of cobalt protoporphyrin, a specific HO-1 inducer, potently suppressed LPS-induced NO production. Hydrangenol also promoted nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and subsequently increased its binding activity at the specific antioxidant response element sites. Additionally, transient knockdown of Nrf2 significantly downregulated hydrangenol-induced HO-1 expression, indicating that hydrangenol-induced Nrf2 is an upstream regulator of HO-1. Taken together, these data suggest that hydrangenol attenuates NO production and iNOS expression in LPS-stimulated BV2 microglial cells by inhibiting NF-κB activation and by stimulating the Nrf2-mediated HO-1 signaling pathway. Therefore, hydrangenol is a promising therapeutic agent for treatment of LPS-mediated inflammatory diseases.     

Cudratricusxanthone A from Cudrania tricuspidata suppresses pro-inflammatory mediators through expression of anti-inflammatory heme oxygenase-1 in RAW264.7 macrophages

Cudratricusxanthone A (CTXA), isolated from the roots of Cudrania tricuspidata Bureau (Moraceae) has an isoprenylated xanthone skeleton that is known to exert a variety of biological activities. In the present study, we demonstrated that CTXA inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide (NO) synthase (iNOS) expression, and thereby reduced COX-2-derived prostaglandin E2 (PGE₂) and iNOS-derived NO production in lipopolysaccharide (LPS)-stimulated macrophages. Similarly, CTXA suppressed tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) production. Moreover, CTXA inhibited the induced phosphorylation and degradation of IκB-α as well as the LPS-induced increase in p65 in the nuclear fraction of macrophages. CTXA also induced heme oxygenase-1 (HO-1) expression and increased heme oxygenase (HO) activity in RAW264.7 macrophages. We also demonstrated that the effects of CTXA on LPS-induced PGE₂, NO, TNF-α, and IL-1β production were partially reversed by the HO-1 inhibitor tin protoporphyrin, suggesting that CTXA-induced HO-1 expression was partly responsible for the resulting anti-inflammatory effects of the drug. Thus CTXA was shown to be an effective HO-1 inducer, capable of inhibiting macrophage-derived pro-inflammatory mediators.     

Anti-inflammatory effect of corymbocoumarin from Seseli gummiferum subsp. corymbosum through suppression of NF-κB signaling pathway and induction of HO-1 expression in LPS-stimulated RAW 264.7 cells

This study investigated the anti-inflammatory activity of corymbocoumarin, an angular-type pyranocoumarin isolated from Seseli gummiferum subsp. corymbosum in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Corymbocoumarin not only inhibited the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), but also inhibited the protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Corymbocoumarin also attenuated pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Investigation of the effect on nuclear factor κB (NF-κB) signaling pathway showed that corymbocoumarin inhibited the phosphorylation of Akt and inhibitory κB (IκB)-α and decreased the subsequent translocation of the p65 and p50 NF-κB subunits to the nucleus. A further study revealed that corymbocoumarin exerted anti-inflammatory activity through induction of heme oxygenase (HO)-1 expression. The in vivo study showed that corymbocoumarin (20 mg/kg, i.p.) reduced paw swelling in carrageenan-induced acute inflammation model. Taken together, these results suggest that corymbocoumarin exerts its anti-inflammatory effect in LPS-stimulated RAW 264.7 cells by suppressing NF-κB activation and inducing HO-1 expression. Corymbocoumarin may provide a useful therapeutic approach for inflammation-associated diseases.     

Anti-inflammatory activity of bark of Dioscorea batatas DECNE through the inhibition of iNOS and COX-2 expressions in RAW264.7 cells via NF-κB and ERK1/2 inactivation

We identified a bioactive herbal medicine with anti-inflammatory activity from an ethanol extract derived from the bark of Dioscorea batatas DECNE (BDB) in RAW264.7 cells. We examined the effects of BDB on nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in LPS-induced RAW264.7 cells. BDB consistently inhibited both NO and PGE₂ production in a dose-dependent manner, with an IC₅₀ of 87–71 μg/ml, respectively. The reduction of NO and PGE₂ production were accompanied by a reduction in iNOS and COX-2 protein expression, as evaluated by Western blotting. To evaluate the action mode of BDB and its ability to inhibit iNOS and COX-2 protein expression, we assessed the effects of BDB on nuclear factor-κB (NF-κB) DNA-binding activity, NF-κB-dependent reporter gene activity, inhibitory factor-κB (IκB) phosphorylation and degradation, and p65 nuclear translocation. BDB suppressed DNA-binding activity and reporter gene activity as well as translocation of the NF-κB p65 subunit. BDB also down-regulated IκB kinase (IKK), thus inhibiting LPS-induced both phosphorylation and the degradation of IκBα. In addition, BDB also inhibited the LPS-induced activation of ERK1/2.     

Ethyl linoleate from garlic attenuates lipopolysaccharide-induced pro-inflammatory cytokine production by inducing heme oxygenase-1 in RAW264.7 cells

In the present study, an essential fatty acid, ethyl linoleate (ELA), was isolated from the cloves of Allium sativum, and its structure was elucidated by NMR and GC-MS analyses. In vitro systems were used to evaluate the anti-inflammatory activity of ELA. Our results indicate that ELA down-regulates inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression and thereby reduces nitric oxide (NO) and prostaglandin E₂ production in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Immunofluorescent microscopy and western blot analyses revealed that these effects were mediated by impaired translocation of nuclear factor (NF)-κB and inhibition of phosphorylation of mitogen activated protein kinases. Furthermore, ELA exerted its anti-inflammatory activity by inducing heme oxygenase-1 (HO-1) expression, as determined by HO-1 small interfering (Si) RNA system. Si RNA-mediated knock-down of HO-1 abrogated the inhibitory effects of ELA on the production of NO, TNF-α, IL-1β, and IL-6 in LPS-induced macrophages. These findings indicate the potential therapeutic use of ELA as an anti-inflammatory agent.     

人参总皂苷在巨噬细胞RAW264.7中降低脂多糖诱导的炎症和氧化应激

目的:通过脂多糖诱导巨噬细胞RAW264.7建立炎症和氧化应激模型,探讨人参总皂苷的抗炎和抗氧化效果以及对脂多糖诱导的巨噬细胞RAW264.7自噬水平的影响。方法:培养RAW264.7细胞,给予脂多糖刺激并加入不同浓度人参总皂苷,使用硝酸还原酶法检测细胞内一氧化氮水平;ELISA法检测小鼠肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)的分泌;DCFH-DA荧光探针法检测人参总皂苷处理后活性氧的变化;超氧化物阴离子荧光探针(dihydroethidium, DHE)检测细胞内超氧化物阴离子水平;吖啶橙染色法检测自噬体的形成;Western Blot法检测COX-2、NF-кB、Nrf2、HO-1、GCLC、GCLM、Beclin1、ATG7和LC3的蛋白表达。结果:与脂多糖模型组相比,随着TGS的浓度增加,细胞一氧化氮水平、TNF-α的分泌降低,细胞内活性氧和超氧阴离子的含量降低,巨噬细胞RAW264.7酸性自噬体的数量增加;Nrf2、HO-1、GCLC、GCLM、Beclin1、ATG7及LC3的蛋白表达提高,COX-2、NF-кB的蛋白表达降低。结论:在...     

Tormentic acid, a triterpenoid saponin, isolated from Rosa rugosa, inhibited LPS-induced iNOS, COX-2, and TNF-α expression through inactivation of the nuclear factor-κb pathway in RAW 264.7 macrophages

We previously reported that extract of Rosa rugosa root and its active triterpenoids constituents exhibit anti-nociceptive and anti-inflammatory effects in animal models. However, little is known about the effects and the molecular mechanism of the 19α-hydroxyursane-type triterpenoids. Among the tested 19α-hydroxyursane-type triterpenoids (kaji-ichigoside F(1), rosamultin, euscaphic acid, tormentic acid (TA)), TA was found to most potently inhibit the production of nitric oxide (NO) in RAW 264.7 cells. We investigated the anti-inflammatory effects and its underlying molecular mechanisms of TA in lipopolysaccaride (LPS)-stimulated RAW 264.7 cells. TA dose-dependently reduced the productions of NO, prostaglandin E(2) (PGE(2)), and tumor necrosis factor-α (TNF-α) induced by LPS. In addition, TA significantly suppressed the LPS-induced expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α at the mRNA and protein levels. Moreover, treatment with TA decreased LPS-induced DNA binding of nuclear factor-kappa B (NF-κB) and nuclear translocation of p65 and p50 subunits of NF-κB. Consistent with these findings, TA also suppressed the LPS-stimulated degradation and phosphorylation of inhibitor of kappa B-α (IκB-α). Taken together, these results suggest that the anti-inflammatory activity of TA is associated with the down-regulation of iNOS, COX-2, and TNF-α through the negative regulation of the NF-κB pathway in RAW 264.7 cells.