Anti-inflammatory potential of Antrodia Camphorata through inhibition of iNOS, COX-2 and cytokines via the NF-kappaB pathway

Antrodia camphorata (A. camphorata), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant and anticancer effects. In the present study, therefore, we have examined the effects of the fermented culture broth of A. camphorata (25-100 microg/ml) in terms of lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production, and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in RAW 264.7 macrophages. Our results indicate concentration-dependent A. camphorata inhibition of LPS-induced NO and PGE2 production, without appreciable cytotoxicity on the RAW 264.7 cells. A. camphorata also attenuates the production of LPS-induced tumor necrosis factor (TNF-alpha) and interleukin (IL)-1beta. Furthermore, A. camphorata blocks the IkappaB-alpha degradation induced by LPS. These results indicate that A. camphorata inhibits LPS induction of cytokine, iNOS and COX-2 expression by blocking NF-kappaB activation. Therefore, we report the first confirmation of the anti-inflammatory potential of this traditionally employed herbal medicine in vitro.     

Cyclooxygenase-2 (COX-2)-dependent and -independent anticarcinogenic effects of celecoxib in human colon carcinoma cells

Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, is the only non-steroidal anti-inflammatory drug so far which has been approved by the FDA for adjuvant treatment of patients with familial adenomatous polyposis. The molecular mechanism responsible for the anticarcinogenic effects of celecoxib is still not fully understood. To investigate the extent to which the anticarcinogenic effect of celecoxib depends on COX-2 expression, we transfected human colon carcinoma cells (Caco-2) with the human COX-2 cDNA, in both sense and in antisense orientation, to generate cells which either overexpress COX-2 (human COX-2-sense, hCOX-2-s), express no COX-2 (human COX-2-antisense, hCOX-2-as) or express only very small amounts of COX-2 (control cells). Treatment of these cells with celecoxib dose-dependently (0-100microM) reduced cell survival which was accompanied by an induction of a G(0)/G(1) phase block and apoptosis. The effect of celecoxib treatment on both, cell survival and induction of apoptosis in hCOX-2-as cells was less marked than in the COX-2-expressing cells. Apoptosis was accompanied by an activation of caspase-3 and caspase-9 and cytochrome c release. In contrast, we observed no difference in sensitivity with regard to the induction of a cell cycle block between the different cell clones. The G(0)/G(1) phase block caused by celecoxib correlated with a decrease in expression levels of cyclin A and cyclin B1 and an increase in the expression of the cell cycle inhibitory proteins p21(Waf1) and p27(Kip1) irrespective of the type of cell used. These data indicate that apoptosis-inducing effects of celecoxib partly depend on COX-2 expression of the cells, whereas induction of a cell cycle block occurred COX-2 independently. Thus, the anticarinogenic effects of celecoxib can be explained by both COX-2-dependent and -independent mechanisms.     

Transforming growth factor-beta1 stimulates heme oxygenase-1 expression via the PI3K/Akt and NF-kappaB pathways in human lung epithelial cells

A previous report showed that transforming growth factor-β1 (TGF-β1) can induce heme oxygenase-1 (HO-1) expression, attenuate cellular injury, and maintain tissue homeostasis. In this study, we investigated the involvement of phosphoinositide-3-OH-kinase (PI3K)/Akt and the nuclear factor-κB (NF-κB) signaling pathway in TGF-β1-induced HO-1 expression in human lung epithelial cells (A549). Treatment of A549 cells with TGF-β1 caused HO-1 to be expressed in a concentration- and time-dependent manner. Treatment of A549 cells with LY 294002 (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one, a PI3K inhibitor), an Akt inhibitor, and the dominant negative mutant of Akt (Akt DN) inhibited TGF-β1-induced HO-1 expression and HO-1-luciferase activity. Stimulation of cells with TGF-β1 caused an increase in Akt phosphorylation in a time-dependent manner, which was inhibited by wortmannin and LY 294002 (PI3K inhibitors). In addition, treatment of A549 cells with Bay 117082 ((E)-3-[4-methylphenylsulfonyl]-2-propenenitrile, an IκB phosphorylation inhibitor), pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor), and the dominant negative mutant of IκB (IκBM) inhibited TGF-β1-induced HO-1 expression and HO-1-luciferase activity. Treatment of A549 cells with TGF-β1-induced IκB kinase /β (IKK/β) phosphorylation, IκB phosphorylation, IκB degradation, p65 Ser536 phosphorylation, and κB-luciferase activity. The TGF-β1-mediated increases in IKK/β phosphorylation, p65 Ser536 phosphorylation, and κB-luciferase activity were inhibited by LY 294002, an Akt inhibitor, and Akt DN. Taken together, these results suggest that the PI3K/Akt dependent IKK/β/NF-κB signaling pathway plays an important role in TGF-β1-induced HO-1 expression in A549 cells.     

Curcumin down regulates smokeless tobacco-induced NF-kappaB activation and COX-2 expression in human oral premalignant and cancer cells

Smokeless tobacco (ST) consumption is a major cause of oral cancer in South East Asia including India. Recently, we showed that exposure to smokeless tobacco extract (STE) (khaini) results in increased expression and activation of nuclear factor-kappaB (NF-kappaB) and its downstream target cyclooxygenase-2 (COX-2) in human oral cell systems in vitro. The present study was designed to test the hypothesis that curcumin may inhibit the activation of NF-kappaB in ST exposed oral premalignant and cancer cells. Exposure of oral premalignant and cancer cells to curcumin resulted in significant decrease in cell viability and induced apoptosis. STE-induced nuclear translocation and DNA-binding activity of NF-kappaB were inhibited in curcumin pretreated oral premalignant and cancer cells in vitro. Curcumin treatment led to decreased expression of NF-kappaB and COX-2. The tobacco specific nitrosamine, 4-(methylnitrosamino-)-1-(3-pyridyl)-1-butanone (NNK), is one of the carcinogenic components of STE (khaini). We demonstrate that curcumin pretreatment abrogated NNK-induced activation of NF-kappaB and COX-2 expression, suggesting that NNK is one of the factors in STE (khaini) modulated by curcumin. In conclusion, our findings demonstrate for the first time that curcumin downregulates STE (khaini) or NNK-induced NF-kappaB and COX-2 in oral premalignant and cancer cells in vitro.     

Concentration-dependent bifunctional effect of TGF-beta 1 on immunoglobulin production: a role for Smad3 in IgA production in vitro

Injury to the liver results in rapid induction of transforming growth factor-beta1 (TGF-beta(1)) consistent with a role for TGF-beta(1) in repairing damaged tissue. In addition to its ubiquitous role in injury repair, TGF-beta(1) is also well established as a critical regulator of immune homeostasis; however, its mechanisms of action remain enigmatic. We have previously demonstrated that the hepatotoxic chlorinated hydrocarbon, carbon tetrachloride, suppresses helper T-lymphocyte function in a TGF-beta(1)-dependent manner. Here, we report that, in opposition to its immunosuppressive effects at picomolar concentrations, femtomolar concentrations of TGF-beta(1) augment T cell-dependent anti-sRBC IgM antibody forming cell (AFC) and T cell-independent DNP-Ficoll-induced AFC responses. These data support a concentration-dependent bifunctional effect by TGF-beta(1) on humoral immune responses in vitro. We further investigated a putative mechanistic role for Smad3, an intracellular mediator of TGF-beta(1) signaling, in propagating the inhibitory effects of TGF-beta(1) on humoral immune responses. Relative to wild type littermates, splenocytes from mice homologous for a null mutation in the gene encoding the TGF-beta receptor-activated Smad3 (Smad3(Exon8-/-)) were less sensitive to inhibition by TGF-beta(1) following anti-sRBC- and LPS-sensitization in vitro. In agreement, inhibition of IgM protein production by TGF-beta(1) was also dampened in LPS-sensitized Smad3(Exon8-/-) splenic B cells. Moreover, stimulation of IgA by TGF-beta(1) was abrogated in LPS-sensitized Smad3(Exon8-/-) splenocytes suggesting an additional role for Smad3 in regulating IgA production in vitro. Our results suggest that the effects of TGF-beta(1) on humoral immune responses fundamentally differ in a concentration-dependent manner and are mediated, in part, through Smad3 signaling.     

Urocortin induced expression of COX-2 and ICAM-1 via corticotrophin-releasing factor type 2 receptor in rat aortic endothelial cells

Background and purpose:

Our previous study showed that urocortin (Ucn1) exacerbates the hypercoagulable state and vasculitis in a rat model of sodium laurate-induced thromboangiitis obliterans. Furthermore, the inflammatory molecules COX-2 and ICAM-1 may participate in this effect. In the present study, the effects of Ucn1 on COX-2 and ICAM-1 expression in lipopolysaccharide (LPS)-induced rat aortic endothelial cells (RAECs) were investigated and the mechanisms involved explored.

Experimental approach:

RAECs were isolated from adult male Wistar rats, and identified at the first passage. Experiments were performed on cells, from primary culture, at passages 5–8. The expression of COX-2 and ICAM-1 at both mRNA and protein levels was determined by semi-quantitative RT-PCR and Western blot analysis. Levels of PGE₂ and soluble ICAM-1 (sICAM-1) in culture medium were measured by enzyme-linked immunosorbent assay. Furthermore, the phosphorylation status of p38MAPK, ERK1/2, JNK, Akt and NF-κB was analysed by Western blot; nuclear translocation of NF-κB was observed by immunofluorescence.

Key results:

Ucn1 augmented LPS-induced expression of COX-2 and ICAM-1 in RAECs in a time- and concentration-dependent manner. Ucn1 increased PGE₂ and sICAM-1 levels. These effects were abolished by the CRF₂ receptor antagonist, antisauvagine-30, but not by the CRF₁ receptor antagonist, NBI-27914. Moreover, Ucn2 activated p38MAPK and augmented NF-κB nuclear translocation and phosphorylation, whereas ERK1/2, JNK and Akt pathways were not involved in this process.

Conclusions and implications:

These findings suggest that Ucn1 exerts pro-inflammatory effects by augmenting LPS-induced expression of COX-2 and ICAM-1 in RAECs via CRF₂ receptors and the activation of p38MAPK and NF-κB.     

Inhibitory action of minocycline on lipopolysaccharide-lnduced release of nitric oxide and prostaglandin E2 in BV2 microglial cells

Microglia are the major inflammatory cells in the central nervous system and become activated in response to brain injuries such as ischemia, trauma, and neurodegenerative diseases including Alzheimer's disease (AD). Moreover, activated microglia are known to release a variety of proinflammatory cytokines and oxidants such as nitric oxide (NO). Minocycline is a semisynthetic second-generation tetracycline that exerts anti-inflammatory effects that are completely distinct form its antimicrobial action. In this study, the inhibitory effects of minocycline on NO and prostaglandin E2 (PGE2) release was examined in lipopolysaccharides (LPS)-challenged BV2 murine microglial cells. Further, effects of minocycline on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels were also determined. The results showed that minocycline significantly inhibited NO and PGE2 production and iNOS and COX-2 expression in BV2 microglial cells. These findings suggest that minocycline should be evaluated as potential therapeutic agent for various pathological conditions due to the excessive activation of microglia.     

Anti-inflammatory effect of leaves of Eriobotrya japonica correlating with attenuation of p38 MAPK, ERK, and NF-κB activation in mast cells

Mast cell-mediated allergic inflammation is involved in many diseases such as asthma and sinusitis. Mast cells induce synthesis and production of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 with immune regulatory properties. In the present study, we investigate the effect an unspecified aqueous extract from leaves of Eriobotrya japonica Lindl. (Rosaceae) (LEJL) on the expression of pro-inflammatory cytokines and its possible mechanisms of action in human mast cells (HMC-1). LEJL dose-dependently inhibited phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187 (PMACI)-induced gene expression and secretion of TNF-α, IL-6, and IL-8. LEJL attenuated PMACI-induced activation of nuclear factor (NF)-κB, and specifically blocked activation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) but not that of c-jun N-terminal kinase. The inhibitory effect of LEJL on the pro-inflammatory cytokines was likely NF-κB, p38 MAPK, and ERK dependent. Our in vitro studies provide evidence that LEJL might contribute to the treatment of mast cell-derived allergic inflammatory diseases.     

Synergistic effect of PGD2 via prostanoid DP receptor on TNF-alpha-induced production of MCP-1 and IL-8 in human monocytic THP-1 cells

Prostaglandin (PG) D₂, a major cyclooxygenase metabolite generated predominantly from immunologically stimulated mast cells, is thought to contribute to the pathogenesis of allergic diseases via the two PGD₂ receptors, prostanoid DP receptor and chemoattractant receptor homologous molecule expressed on Th2 cells (CRTH2). Monocytes are known to express the prostanoid DP receptor, however, the role of it in inflammatory responses is still unclear. In the present study, to clarify the functional roles of prostanoid DP receptor on monocytes, we examined the effect of PGD₂ on the production of monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-8 from a human monocytic cell line, THP-1. Single activation of prostanoid DP receptor hardly produced any cytokines or chemokines. However, activation with PGD₂ in the presence of tumor necrosis factor (TNF)-α mediated significant production of MCP-1 and IL-8, but not the other cytokines and chemokines, in comparison to single stimulation with TNF-α. In addition, the selective prostanoid DP receptor antagonist, pinagladin ((Z)-7-[(1R,2R,3S,5S)-2-(benzothiophen-3-ylcarbonylamide)-10-norpinan-3-yl]hept-5-enoic acid) inhibited the production of MCP-1 and IL-8 upon combined stimulation with PGD₂ and TNF-α. The synergistic production of MCP-1 and IL-8 by PGD₂ was mimicked by dibutyryl cAMP (db-cAMP) and was inhibited by a protein kinase A (PKA) inhibitor. Our findings suggest that activation of the prostanoid DP receptor on THP-1 cells enhances TNF-α-induced MCP-1 and IL-8 production via the cAMP/PKA signaling pathway.     

Effect of Zanthoxylum schinifolium on TNF-α-induced vascular inflammation in human umbilical vein endothelial cells

Pro-inflammatory cytokines induce the injury of endothelial cells in response to increases of adhesion molecules, leading to vascular inflammation and the development of atherosclerosis. In this study, we evaluated an ethanol extract of Zanthoxylum schinifolium (EZS) to determine if it inhibits the expressions of cellular adhesion molecules in human umbilical vein endothelial cells (HUVEC). When pretreatment of HUVEC with EZS, EZS suppressed the expression levels of cell adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin induced by TNF-α. The adhesion of HL-60 cells to TNF-α-induced endothelial cells was decreased significantly in a concentration-dependent manner. Furthermore, TNF-α-induced MCP-1 and IL-8 mRNA expression levels were also attenuated by pretreatment with EZS. In addition, EZS suppressed TNF-α-induced production of reactive oxygen species (ROS). EZS inhibited NF-κB activation and IκB-α phosphorylation induced by TNF-α, subsequent degradation of IκB-α. Finally, EZS inhibited TNF-α-induced p38 MAPK and c-Jun N-terminal kinase (JNK) phosphorylation. Taken together, these results demonstrate that EZS suppresses vascular inflammatory process, which may be closely related to the inhibition of ROS, JNK, p38 MAPK and NF-κB activation in HUVEC.     

Differential effects of glibenclamide on responses to thromboxane A2 mimic, U46619, in the pulmonary and hindquarters vascular beds of the cat

The inhibitory effects of the oral sulfonylurea, glibenclamide, on vasoconstrictor responses to the thromboxane A₂ mimic, U46619, were investigated in the pulmonary and hindquarters vascular beds of the cat under constant flow conditions. When lobar arterial tone was at resting conditions (14±2 mm Hg), intralobar injections of U46619, prostaglandin F_2α, prostaglandin D₂, angiotensin II, norepinephrine, and BAY K 8644 caused dose-related increases in lobar arterial pressure without altering left atrial pressure. Following an intralobar infusion of glibenclamide (5 mg/kg), vasoconstrictor responses to U46619, prostaglandin F_2α and prostaglandin D₂ were significantly reduced, whereas vasoconstrictor responses to norepinephrine and angiotensin II were not altered and responses to BAY K 8644 were significantly enhanced. When tone in the pulmonary vascular bed was raised to a high steady level (36±3 mm Hg), glibenclamide in a dose of 5 mg/kg i.a. markedly attenuated responses to injections of U46619 and reduced the vasodilator responses to the K⁺-ATP channel opener, levcromakalim, whereas responses to acetylcholine and S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide donor, were not changed. In the hindquarters vascular bed of the cat, administration of glibenclamide in a dose of 5 mg/kg i.a. had no significant effect on vasoconstrictor responses to U46619, norepinephrine or angiotensin II. Hindquarters vasodilator responses to levcromakalim, but not to nitric oxide, were decreased significantly following administration of glibenclamide. These data suggest that glibenclamide, in addition to inhibiting K⁺-ATP channels, has thromboxane A₂ receptor blocking activity in the pulmonary vascular bed of the cat. These data also suggest that vasoconstrictor responses to U46619 may be mediated by different thromboxane A₂ receptors with different binding affinities in the pulmonary and in the hindquarters vascular beds of the cat.     

Differential effects of fluphenazine-N-mustard,on calmodulin activity and on D1 and D2 dopaminergic responses

Fluphenazine-N-mustard (FNM) has been shown to irreversibly block dopaminergic receptor sites and inhibit certain dopaminergically-mediated behaviors. In this study we measured whether FNM has any differential effects on D₁ and D₂ dopaminergic events. Accordingly, we examined the relative effects of FNM on rotational behavior induced by SKF 38393 (D₁ agonist) and Ly 171555 (D₂ agonist) in mice with unilateral, 6-hydroxydopamine-induced lesions of the striatum and the effects of FNM on the binding of [³H]Sch 23390 (D₁ ligand) and [³H]spiroperidol (D₂ ligand) to mouse striatal membranes. FNM inhibited rotational behavior induced by Ly 171555 at doses 10-fold lower than those required to block rotations induced by SKF 38393 (ID₅₀ values: Ly 171555=1.8 mole/kg, IP; SKF 38393=16 mole/kg, IP). The inhibitory effect of high doses of FNM (20 mole/kg) on rotational behavior was overcome by increasing the dose of SKF 38393 and apomorphine, a nonselective dopaminergic agonist. By contrast, the inhibitory effect of FNM was not overcome by Ly 171555, even when given in doses more than 100 times its ED₅₀. Using striatal homogenates in vitro, FNM inhibited the specific binding of [³H]spiroperidol at concentrations about 10-fold lower than those required to inhibit the binding of [³H]Sch 23390 (IC₅₀ values: [³H]spiroperidol=90 nM; [³H]Sch 23390=840 nM). Considerably higher concentrations of FNM were needed to irreversibly inhibit calmodulin activity in striatal homogenates (IC₅₀=10 M). In vivo, FNM inhibited the binding of [³H]spiroperidol measured ex vivo (ID₅₀=4 mole/kg), but did not inhibit the binding of [³H]Sch 23390, even when given in doses as high as 100 mole/kg. These studies indicate that FNM was approximately 10 times more potent at inhibiting D₂-than D₁-mediated behavior and at displacing D₂ versus D₁ ligands and suggest that FNM may be useful for studying and differentiating D₂- and D₁-mediated events.     

Structure-specific control of differentiation and apoptosis of human promyelocytic leukemia (HL-60) cells by A-ring diastereomers of 2-methyl- 1α,25-dihydroxyvitamin D3 and its 20-epimer

1α,25-Dihydroxyvitamin D₃ (1α,25(OH)₂D₃) has been shown to modulate not only proliferation and differentiation but also apoptosis of malignant cells, indicating that it would be useful for the treatment of hyperproliferative diseases such as cancer and psoriasis. Little information is available concerning structural motifs of the 1α,25(OH)₂D₃ molecule responsible for modulation of differentiation and apoptosis. We synthesized all possible A-ring diastereomers of the 2-methyl-1α,25(OH)₂D₃ and its 20-epimer and evaluated their biological activities in human promyelocytic leukemia (HL-60) cells. Surprisingly, the potent analogues could be clearly divided into two groups: (i) those bearing the 1α- and 3β-hydroxyl groups on the A-ring were potent inducers of differentiation and growth inhibitors of HL-60 cells and (ii) those bearing the 1β-hydroxyl group together with either 3α- or 3β-hydroxyl groups on the A-ring were potent stimulators of apoptosis in these cells. We have clearly identified for the first time the structural motifs on the basis of the stereochemistry of both hydroxyl groups at positions 1 and 3 of the A-ring of the 1α,25(OH)₂D₃ molecule responsible for the induction of differentiation and apoptosis of HL-60 cells. These findings provide useful information not only for structure–function studies of 1α,25(OH)₂D₃ analogues but also for the development of therapeutic agents for the treatment of leukemia and other cancers.