interleukin-8 and epigallocatechin-gallate

We previously reported that the combination of two safe proteostasis regulators, cysteamine and epigallocatechin gallate (EGCG), can be used to improve deficient expression of the cystic fibrosis transmembrane conductance regulator (CFTR) in patients homozygous for the CFTR Phe508del mutation. Here we provide the proof-of-concept that this combination treatment restored CFTR function and reduced lung inflammation (P<0.001) in Phe508del/Phe508del or Phe508del/null-Cftr (but not in Cftr-null mice), provided that such mice were autophagy-competent. Primary nasal cells from patients bearing different class II CFTR mutations, either in homozygous or compound heterozygous form, responded to the treatment in vitro. We assessed individual responses to cysteamine plus EGCG in a single-centre, open-label phase-2 trial. The combination treatment decreased sweat chloride from baseline, increased both CFTR protein and function in nasal cells, restored autophagy in such cells, decreased CXCL8 and TNF-α in the sputum, and tended to improve respiratory function. These positive effects were particularly strong in patients carrying Phe508del CFTR mutations in homozygosity or heterozygosity. However, a fraction of patients bearing other CFTR mutations failed to respond to therapy. Importantly, the same patients whose primary nasal brushed cells did not respond to cysteamine plus EGCG in vitro also exhibited deficient therapeutic responses in vivo. Altogether, these results suggest that the combination treatment of cysteamine plus EGCG acts 'on-target' because it can only rescue CFTR function when autophagy is functional (in mice) and improves CFTR function when a rescuable protein is expressed (in mice and men). These results should spur the further clinical development of the combination treatment.

Topics: Adolescent; Animals; Autophagy; Biomarkers; Catechin; Child; Cysteamine; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Disease Models, Animal; Drug Therapy, Combination; Homozygote; Humans; Interleukin-8; Lung; Mice; Mice, Knockout; Mutation; Sputum; Tumor Necrosis Factor-alpha

Restoration of BECN1/Beclin 1-dependent autophagy and depletion of SQSTM1/p62 by genetic manipulation or autophagy-stimulatory proteostasis regulators, such as cystamine, have positive effects on mouse models of human cystic fibrosis (CF). These measures rescue the functional expression of the most frequent pathogenic CFTR mutant, F508del, at the respiratory epithelial surface and reduce lung inflammation in Cftr(F508del) homozygous mice. Cysteamine, the reduced form of cystamine, is an FDA-approved drug. Here, we report that oral treatment with cysteamine greatly reduces the mortality rate and improves the phenotype of newborn mice bearing the F508del-CFTR mutation. Cysteamine was also able to increase the plasma membrane expression of the F508del-CFTR protein in nasal epithelial cells from F508del homozygous CF patients, and these effects persisted for 24 h after cysteamine withdrawal. Importantly, this cysteamine effect after washout was further sustained by the sequential administration of epigallocatechin gallate (EGCG), a green tea flavonoid, both in vivo, in mice, and in vitro, in primary epithelial cells from CF patients. In a pilot clinical trial involving 10 F508del-CFTR homozygous CF patients, the combination of cysteamine and EGCG restored BECN1, reduced SQSTM1 levels and improved CFTR function from nasal epithelial cells in vivo, correlating with a decrease of chloride concentrations in sweat, as well as with a reduction of the abundance of TNF/TNF-alpha (tumor necrosis factor) and CXCL8 (chemokine [C-X-C motif] ligand 8) transcripts in nasal brushing and TNF and CXCL8 protein levels in the sputum. Altogether, these results suggest that optimal schedules of cysteamine plus EGCG might be used for the treatment of CF caused by the F508del-CFTR mutation.

Topics: Adaptor Proteins, Signal Transducing; Administration, Oral; Adolescent; Adult; Animals; Apoptosis Regulatory Proteins; Beclin-1; Catechin; Cell Membrane; Child; Chlorides; Cystamine; Cysteamine; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Homozygote; Humans; Interleukin-8; Male; Membrane Proteins; Mice; Mice, Inbred CFTR; Mice, Transgenic; Mutation; Phenotype; Pilot Projects; Sequestosome-1 Protein; Tumor Necrosis Factor-alpha; Young Adult

Venous thrombosis (VT) is one of the most frequent cardiovascular diseases, which seriously endangers people's health. Recently, the protective role of epigallocatechin-3-gallate (EGCG) against multiple cardiovascular diseases has been well studied. Nevertheless, whether EGCG is implicated in the progression of VT is still unclear.. Rat models of VT were established by inferior vena cava (IVC) ligation. Histological characterization of the IVC tissues was examined by hematoxylin-eosin (H&E) staining. TUNEL assay was utilized to detect cell apoptosis in IVC tissues. The concentrations of the oxidative stress biomarkers, malondialdehyde (MDA) and superoxide dismutase (SOD), were estimated by corresponding kits. In addition, the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 in rat plasma were estimated by ELISA. Further, the expression levels of apoptosis markers (Bax, Bcl-2, and Cleaved-caspase 3) as well as key molecules p-PI3K and p-AKT in phosphoinositide 3-kinase (PI3K)/AKT signaling pathway were assessed by western blot.. Compared to the sham group, the model group showed obvious thrombus formation in IVC tissues, while the EGCG treatment significantly repressed thrombosis. EGCG inhibited cell apoptosis in IVC tissues of VT rat models. The decreased SOD concentration and increased MDA concentration in the plasma of VT rats were reversed by EGCG treatment. Additionally, the elevated levels of TNF-α, IL-6 and IL-8 in the plasma of VT rats can be partially reduced by the treatment of EGCG. Finally, we also found that EGCG reduced the levels of phosphorylated (p)-PI3K and p-AKT in IVC tissues of VT rat models, indicating that the hyperactivation of the PI3K/AKT signaling pathway was inhibited by EGCG.. This study proves that EGCG alleviates thrombosis, cell apoptosis, inflammatory response, and oxidative stress injury in VT by inactivating PI3K/AKT signaling pathway.

Topics: Animals; Apoptosis; Catechin; Interleukin-6; Interleukin-8; Myocardial Reperfusion Injury; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Superoxide Dismutase; Thrombosis; Tumor Necrosis Factor-alpha

Receptor activator of NF-κB ligand (RANKL) as an osteoclast differentiation factor induces inflammatory reactions via production of thymic stromal lymphopoietin (TSLP). Epigallocatechin gallate (EGCG) is the major and the most active compound in green tea and has anti-inflammatory, anti-cancer, anti-oxidant, and neuroprotective effects. However, the effect and molecular mechanisms of EGCG are still unknown in RANKL-induced inflammatory reactions. Here we investigated the immuno-regulatory effects and its molecular mechanisms of epigallocatechin gallate (EGCG) in RANKL-stimulated human mast cell line, HMC-1 cells. In this study, EGCG prevented expression of PI3 Kinase and phosphorylation of mitogen-activated protein (MAP) Kinases in RANKL-stimulated HMC-1 cells. EGCG prevented caspase-1 activity and decreased transcriptional activity of nuclear factor (NF)-κB by suppressing inhibitory protein κBα phosphorylation in RANKL-stimulated HMC-1 cells. EGCG has been shown to prevent production and mRNA expression of TSLP, interleukin (IL)-1β, IL-6, and IL-8 by RANKL without cytotoxicity. Furthermore, EGCG prevented degranulation of mast cell in RANKL-stimulated HMC-1 cells. Overall, these results suggest that EGCG acts as a natural agent for preventing and treating RANKL-mediated inflammatory diseases by targeting PI3 Kinase, MAP Kinase, caspase-1, and NF-κB signaling cascade in mast cells.

Topics: Caspase 1; Catechin; Cell Line; Cell Survival; Cytokines; Elafin; Histamine; Humans; Inflammation; Interleukin-1beta; Interleukin-6; Interleukin-8; Mast Cells; Mitogen-Activated Protein Kinases; NF-kappa B; RANK Ligand; Signal Transduction; Thymic Stromal Lymphopoietin

Cigarette smoking is the leading cause for the initiation and development of cardiovascular disease (CVD). Oxidative stress and inflammatory responses play important roles in the pathophysiological processes of smoking-induced cardiac injury. (-)-epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, which is made from Camellia sinensis leaves, has been reported to possess potent anti-oxidant property.. This study aims to investigate whether the antioxidant EGCG could alleviate cigarette smoke medium (CSM)-induced inflammation in human AC16 cardiomyocytes in vitro.. Human AC16 cardiomyocytes were pre-treated with EGCG, N-acetyl-L-cysteine (NAC), or specific inhibitors for 30 min before 4% CSM was added. Supernatant was collected for determination of interleukin (IL)-8 by ELISA and cells were collected for flow cytometry, biochemical assays and Western blot analysis.. EGCG treatment significantly attenuated CSM-induced oxidative stress as evidenced by reducing intracellular and mitochondrial reactive oxygen species (ROS) generations and preventing antioxidant depletion. EGCG treatment reduced CSM-induced inflammatory chemokine interleukin (IL)-8 productions in the supernatant via the inhibition of ERK1/2, p38 MAPK and NF-κB pathways. EGCG treatment further inhibited CSM-induced cell apoptosis.. Taken together, EGCG protected against CSM-induced inflammation and cell apoptosis by attenuating oxidative stress via inhibiting ERK1/2, p38 MAPK, and NF-κB activation in AC16 cardiomyocytes. These findings suggest that EGCG with its antioxidant, anti-inflammatory and anti-apoptotic properties may act as a promising cardioprotective agent against ROS-mediated cardiac injury.

Topics: Antioxidants; Apoptosis; Catechin; Cell Line; Humans; Interleukin-8; MAP Kinase Signaling System; Myocarditis; Myocytes, Cardiac; NF-kappa B; Oxidative Stress; Reactive Oxygen Species; Signal Transduction; Smoking

Porcine reproductive and respiratory syndrome virus (PRRSV) remains an economically important pathogen in the global pig industry, effective measures to control the virus are still lacking. (-)-Epigallocatechin-3-gallate (EGCG), the most abundant and bioactive catechin in green tea, has been reported to have antiviral effect against the diverse groups of viruses. In this study, the comprehensive anti-PRRSV activity of EGCG was investigated using various in vitro assays. EGCG effectively inhibited PRRSV infection and replication in porcine alveolar macrophages (PAMs), regardless of whether it was administrated pre- or post-infection, and the cytotoxicity to PAMs was low. Next, anti-PRRSV approaches of EGCG were characterized in MARC-145 cells. EGCG was demonstrated to be able to significantly prevent PRRSV from infecting MARC-145 cells either through blocking of EGCG-treated viruses docking to susceptible cells involving a direct virus-EGCG interaction or by blocking of the infective virus binding to EGCG pre-treated cells via triggering down-regulation of viral receptors and/or related proteins required for infection. In addition, PRRSV replication was suppressed in MARC-145 cells treated with EGCG post-infection, likely because of down-regulation of pro-inflammatory cytokines, such as TNF-α, IL-6 and IL-8. Taken together, these data showed that treatment of primary PAMs with EGCG can inhibit PRRSV infection and revealed that multiple antiviral approaches of EGCG operate in PRRSV-susceptible MARC-145 cells.

Topics: Animals; Antiviral Agents; Catechin; Cell Line; Chlorocebus aethiops; Cytokines; Down-Regulation; Interleukin-6; Interleukin-8; Macrophages, Alveolar; Porcine Reproductive and Respiratory Syndrome; Porcine respiratory and reproductive syndrome virus; Receptors, Virus; Swine; Time Factors; Tumor Necrosis Factor-alpha; Viral Proteins; Virion; Virus Attachment; Virus Replication

In this study, we found that catechins found in green tea (EGCG, EGC, and EC) differentially interfere with the IL-1β signaling pathway which regulates the expression of pro-inflammatory mediators (IL-6 and IL-8) and Cox-2 in primary human rheumatoid arthritis synovial fibroblasts (RASFs). EGCG and EGC inhibited IL-6, IL-8, and MMP-2 production and selectively inhibited Cox-2 expression. EC did not exhibit any inhibitory effects. When we looked at the expression of key signaling proteins in the IL-1β signaling pathway, we found all the tested catechins could inhibit TAK-1 activity. Therefore, the consumption of green tea offers an overall anti-inflammatory effect. Molecular docking analysis confirms that EGCG, EGC, and EC all occupy the active site of the TAK1 kinase domain. However, EGCG occupies the majority of the TAK1 active site. In addition to TAK1 inhibition, EGCG can also inhibit P38 and nuclear NF-κB expression whereas EC and EGC were not effective inhibitors. Our findings suggest one of the main health benefits associated with the consumption of green tea are due to the activity of EGCG and EGC which are both present at higher amounts. Although EGCG is the most effective catechin at inhibiting downstream inflammatory signaling, its effectiveness could be hindered by the presence of EC. Therefore, varying EC content in green tea may reduce the anti-inflammatory effects of other potential catechins in green tea.

Topics: Anti-Inflammatory Agents; Antirheumatic Agents; Arthritis, Rheumatoid; Catalytic Domain; Catechin; Cells, Cultured; Cyclooxygenase 2 Inhibitors; Fibroblasts; Humans; Interleukin-1beta; Interleukin-6; Interleukin-8; MAP Kinase Kinase Kinases; Matrix Metalloproteinase 2; Molecular Docking Simulation; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Phytotherapy; Plants, Medicinal; Protein Binding; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-jun; Signal Transduction; Synovial Membrane; Tea

Inflammation serves an important role in the pathogenesis of myocardial ischemia/reperfusion (I/R) injury. Fragments of endogenous damaged‑associated molecular patterns, recently identified as mitochondrial DNA (mtDNA), have been proven to be a potent pro‑inflammatory mediator. Epigallocatechin‑3‑gallate (EGCG) is able to regulate the expression levels of a series of inflammatory cytokines. However, the involvement of endogenous mtDNA in EGCG‑regulated inflammatory activities in the context of myocardial I/R injury remains to be elucidated. The present study was designed to investigate the role of mtDNA in EGCG‑mediated myocardial protection in a rat I/R model. Significant positive correlations between elevated plasma mtDNA copy numbers and the expression levels of tumor necrosis factor (TNF) and interleukins (IL)‑6 and ‑8 were observed in the myocardial tissue following an I/R injury (P<0.05). However, EGCG administered prior to reperfusion was able to effectively downregulate the expression levels of plasma mtDNA, TNF and IL‑6 and ‑8 in the myocardial tissue following an I/R injury (P<0.05). Limited infarct size, reduced severity of myocardial injury and decreased incidence of ventricular arrhythmia were observed in the EGCG‑treated group. However, the beneficial effects of EGCG in preventing myocardial I/R injury may be eliminated by a specific phosphoinositide‑3‑kinase (PI3K) inhibitor. These results suggested that EGCG‑mediated cardioprotective effects may be achieved by inhibiting the release of mtDNA from damaged mitochondria and that this protection was at least in part dependent on the PI3K/RAC‑α serine/threonine‑protein kinase associated signaling pathway.

Topics: Androstadienes; Animals; Catechin; Creatine Kinase; DNA, Mitochondrial; Enzyme-Linked Immunosorbent Assay; Interleukin-6; Interleukin-8; L-Lactate Dehydrogenase; Male; Myocardial Reperfusion Injury; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protective Agents; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Signal Transduction; Tumor Necrosis Factor-alpha; Wortmannin

Transforming growth factor β-activated kinase 1 (TAK1) is a key MAPKKK family protein in interleukin-1β (IL-1β), tumor necrosis factor (TNF), and Toll-like receptor signaling. This study was undertaken to examine the posttranslational modification of TAK1 and its therapeutic regulation in rheumatoid arthritis (RA).. The effect of TAK1, IL-1 receptor-associated kinase 1 (IRAK-1), and TNF receptor-associated factor 6 (TRAF6) inhibition was evaluated in IL-1β-stimulated human RA synovial fibroblasts (RASFs). Western blotting, immunoprecipitation, and 20S proteasome assay were used to study the ubiquitination process in RASFs. The efficacy of epigallocatechin-3-gallate (EGCG), a potent antiinflammatory molecule, in regulating these processes in RASFs was evaluated. Molecular docking was performed to examine the interaction of EGCG with human TAK1, IRAK-1, and TRAF6. These findings were confirmed using a rat model of adjuvant-induced arthritis (AIA).. Inhibition of TAK1, but not IRAK-1 or TRAF6, completely abrogated IL-1β-induced IL-6 and IL-8 synthesis in RASFs. EGCG inhibited TAK1 phosphorylation at Thr(184/187) and occupied the C(174) position, an ATP-binding site, to inhibit its kinase activity. EGCG pretreatment also inhibited K(63) -linked autoubiquitination of TRAF6, a posttranslational modification essential for TAK1 autophosphorylation, by forming a stable H bond at the K(124) position on TRAF6. Furthermore, EGCG enhanced proteasome-associated deubiquitinase expression to rescue proteins from proteasomal degradation. Western blot analyses of joint homogenates from rats with AIA showed a significant increase in K(48) -linked polyubiquitination, TAK1 phosphorylation, and TRAF6 expression when compared to naive rats. Administration of EGCG (50 mg/kg/day) for 10 days ameliorated AIA in rats by reducing TAK1 phosphorylation and K(48) -linked polyubiquitination.. Our findings provide a rationale for targeting TAK1 for the treatment of RA with EGCG.

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Blotting, Western; Catechin; Disease Models, Animal; Female; Fibroblasts; Humans; Immunoprecipitation; In Vitro Techniques; Interleukin-1 Receptor-Associated Kinases; Interleukin-1beta; Interleukin-6; Interleukin-8; Lysine; MAP Kinase Kinase Kinases; Molecular Docking Simulation; Proteasome Endopeptidase Complex; Protein Processing, Post-Translational; Rats; Rats, Inbred Lew; Synovial Membrane; TNF Receptor-Associated Factor 6; Ubiquitination

Orbital fibroblasts have been reported to be an important effector cells for the development of thyroid-associated ophthalmopathy (TAO). Orbital fibroblasts secrete various inflammatory cytokines in response to an inflammatory stimulation, leading to TAO-related tissue swelling. It has also been reported that (-)-epigallocatechin-3-gallate (EGCG), a major polyphenolic constituent of green tea, has antioxidant and anti-inflammatory properties. In the current study, we investigated the issue of whether or how EGCG affects the interleukin (IL)-1β-induced secretion of IL-8 in human orbital fibroblasts from TAO patients. Treatment with EGCG significantly reduced the level of IL-1β-induced secretion of IL-8 and the expression of IL-8 mRNA. IL-1β-induced the degradation of IκBα, and the phosphorylation of p38 and ERK, and the IL-1β-induced expression of IL-8 mRNA was inhibited by specific inhibitors, such as BAY-117085 for NF-kB, SB203580 for p38, and PD98059 for ERK. In addition, treatment with EGCG inhibited the IL-1β-induced degradation of IκBα, and the phosphorylation of p38 and ERK. However, pre-treatment with antioxidants, NVN and NAC, which suppressed ROS generation, did not reduce IL-8 expression in IL-1β-treated orbital fibroblasts, suggesting that the IL-1β-induced IL-8 expression is not mediated by the generation of ROS. These results show that EGCG suppresses the IL-1β-induced expression of IL-8 through inhibition of the NF-κB, p38, and ERK pathways. These findings could contribute to the development of new types of EGCG-containing pharmacological agents for use in the treatment of TAO.

Topics: Antioxidants; Catechin; Fibroblasts; Graves Ophthalmopathy; Humans; Interleukin-1beta; Interleukin-8; MAP Kinase Signaling System; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Reactive Oxygen Species

Inflammation is an important therapeutic target. Due to their potency, steroidal drugs dominate the current treatment of inflammatory disorders. However, steroidal drugs can also exert a broad range of side effects and appear not always effective. This calls for the development of alternative drugs with a different mechanism of action, which are likely to be found in the field of natural products (NPs). For many NPs strong anti-inflammatory effects have been described, but usually investigating a single compound in a single assay. In this study, eight promising NPs were selected and tested against the strong anti-inflammatory drug prednisolone. For this head-to-head comparison, in vitro assays were used which represent different pathways of the inflammatory response: TNF-α and IL-6 expression by macrophages, IL-8 expression by colon epithelial cells, ROS production in polymorphonuclear leukocytes and platelet activation in whole blood. Performance profiles were established which allowed us to identify curcumin, berberine chloride and epigallocatechin gallate as potential alternatives for prednisolone or other glucocorticoids in inflammation.

Topics: Acetophenones; Animals; Anti-Inflammatory Agents; Berberine; Biological Products; Blood Platelets; Caco-2 Cells; Catechin; Cell Line; Curcumin; Humans; Interleukin-6; Interleukin-8; Macrophages; Mice; Neutrophils; Platelet Activation; Pravastatin; Prednisolone; Primary Cell Culture; Reactive Oxygen Species; Stilbenes; Tumor Necrosis Factor-alpha

This study was designed to investigate whether epigallocatechin-3-gallate (EGCG) postconditioning protects the heart against ischemic-reperfusion injury (IRI), and to explore its potential mechanisms in a rat model.. Male Wistar rats were subjected to myocardial ischemia (30 min) and reperfusion (up to 2 h) and the rats were divided into sham group (SO) group, ischemia-reperfusion (I/R) model group and EGCG group. EGCG group were treated with EGCG (10 mg/kg) via intravenous infusion 5 min before reperfusion. Electrocardiogram were applied to record ventricular arrhythmia frequency. The severity of myocardial injury [serum level of lactate dehydrogenase (LDH) and creatine kinase (CK), hematoxylineosin (HE) staining] and ventricular arrhythmia, and the serum levels of inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukins-6 (IL-6) and IL-8] were assessed with ELISA, electrocardiogram and Western blot respectively.. EGCG given before reperfusion could effectively reduce the serum level of LDH and CK and the incidence of ventricular arrhythmia (P < 0.05, respectively), improved the pathological damage. Meanwhile, EGCG could down-regulate the expression levels of TNF-α, IL-6, IL-8 in the myocardial tissue after IRI (P < 0.05, repectively). The expression levels of p-p85 and p-Akt in the EGCG group were significantly up-regulated compared to those in I/R group (P < 0.05, repectively).. EGCG-related anti-inflammatory action could attenuate rat myocardial IRI and this cardioprotective effect might be activated through the PI3K/Akt pathway.

Topics: Animals; Catechin; Creatine Kinase; Interleukin-6; Interleukin-8; Male; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Signal Transduction; Tumor Necrosis Factor-alpha; Up-Regulation

Over the years, several studies have brought evidence suggesting that tea polyphenols, mostly from green tea, may have oral health benefits. Since few data are available concerning the beneficial properties of black tea and its theaflavin derivatives against periodontal disease, the objective of this study was to investigate their antibacterial activity as well as their ability to modulate interleukin-8 and human β-defensin (hBD) secretion in oral epithelial cells. Among the periodontopathogenic bacteria tested, Porphyromonas gingivalis was found to be highly susceptible to the black tea extract and theaflavins. Moreover, our data indicated that the black tea extract, theaflavin and theaflavin-3,3'-digallate can potentiate the antibacterial effect of metronidazole and tetracycline against P. gingivalis. Using lipopolysaccharide-stimulated oral epithelial cells, the black tea extract (100 μg/ml), as well as theaflavin and theaflavin-3,3'-digallate (50 μg/ml) reduced interleukin-8 (IL-8) secretion by 85%, 79%, and 86%, respectively, thus suggesting an anti-inflammatory property. The ability of the black tea extract and its theaflavin derivatives to induce the secretion of the antimicrobial peptides hBD-1, hBD-2 and hBD-4 by oral epithelial cells was then evaluated. Our results showed that the black tea extract as well as theaflavin-3,3'-digallate were able to increase the secretion of the three hBDs. In conclusion, the ability of a black tea extract and theaflavins to exert antibacterial activity against major periodontopathogens, to attenuate the secretion of IL-8, and to induce hBD secretion in oral epithelial cells suggest that these components may have a beneficial effect against periodontal disease.

Topics: beta-Defensins; Biflavonoids; Catechin; Cell Line; Epithelial Cells; Humans; Interleukin-8; Lipopolysaccharides; Microbial Sensitivity Tests; Mouth; Plant Extracts; Porphyromonas gingivalis; Tea

To investigate the effects of (-)-epigallocatechin-3-gallate (EGCG) on human papillomavirus (HPV)-16 oncoprotein-induced angiogenesis in non-small cell lung cancer (NSCLC) cells and the underlying mechanisms.. NSCLC cells (A549 and NCI-H460) transfected with EGFP plasmids containing HPV-16 E6 or E7 oncogene were treated with different concentrations of EGCG for 16 h. The effects of EGCG on angiogenesis in vitro and in vivo were observed. The expression of HIF-1α, p-Akt, and p-ERK1/2 proteins in NSCLC cells was analyzed by Western blot. The levels of HIF-1α mRNA in NSCLC cells were detected by real-time RT-PCR. The concentration of VEGF and IL-8 in the conditioned media was determined by ELISA. HIF-1α, VEGF, and CD31 expression in A549 xenografted tumors of nude mice was analyzed by immunohistochemistry.. HPV-16 E6 and E7 oncoproteins HIF-1α-dependently promoted angiogenesis in vitro and in vivo, which was inhibited by EGCG. Mechanistically, EGCG inhibited HPV-16 oncoprotein-induced HIF-1α protein expression but had no effect on HIF-1α mRNA expression in NSCLC cells. Additionally, 50 and 100 μmol/L of EGCG significantly reduced the secretion of VEGF and IL-8 proteins induced by HPV-16 E7 oncoprotein in NSCLC A549 cells. Meanwhile, HPV-16 E6 and E7 oncoproteins HIF-1α-dependently enhanced Akt activation in A549 cells, which was suppressed by EGCG. Furthermore, EGCG inhibited HPV-16 oncoprotein-induced HIF-1α and HIF-1α-dependent VEGF and CD31 expression in A549 xenografted tumors.. EGCG inhibited HPV-16 oncoprotein-induced angiogenesis conferred by NSCLC through the inhibition of HIF-1α protein expression and HIF-1α-dependent expression of VEGF, IL-8, and CD31 as well as activation of Akt, suggesting that HIF-1α may be a potential target of EGCG against HPV-related NSCLC angiogenesis.

Topics: Angiogenesis Inhibitors; Animals; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Catechin; Cell Line, Tumor; Enzyme-Linked Immunosorbent Assay; Gene Expression; Human papillomavirus 16; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Interleukin-8; Lung Neoplasms; Male; Mice; Mice, Inbred BALB C; Neovascularization, Pathologic; Oncogene Proteins; Oncogene Proteins, Viral; Papillomavirus E7 Proteins; Platelet Endothelial Cell Adhesion Molecule-1; Proto-Oncogene Proteins c-akt; Real-Time Polymerase Chain Reaction; Repressor Proteins; Signal Transduction; Transfection; Vascular Endothelial Growth Factor A

Leukocyte infiltration, up-regulation of proinflammatory cytokines and severe oxidative stress caused by increased amounts of reactive oxygen species are characteristics of inflammatory bowel disease. The catechin (2R,3R)-2-(3,4,5-Trihydroxyphenyl)-3,4-dihydro-1(2H)-benzopyran-3,5,7-triol-3-(3,4,5-trihydroxybenzoate), named epigallocatechin-3-gallate, EGCG, has been demonstrated to exert anti-inflammatory and antioxidative properties, reducing reactive oxygen species in the inflamed tissues. The aim of this study was to evaluate the therapeutic effects of EGCG in a murine model of colitis induced by oral administration of dextran sodium sulfate.. Mice received a daily oral administration of 6.9 mg/kg body weight EGCG or Piper nigrum (L.) alkaloid (2E,4E)-5-(1,3-benzodioxol-5-yl)-1-piperidin-1-ylpenta-2,4-dien-1-one, named piperine (2.9 mg/kg body weight) or the combination of the both - piperine was used in this combination to enhance the bioavailability of EGCG.. In vivo data revealed the combination of EGCG and piperine to significantly reduce the loss of body weight, improve the clinical course and increase overall survival in comparison to untreated groups. The attenuated colitis was associated with less histological damages to the colon and reduction of tissue concentrations of malondialdehyde, the final product of lipid peroxidation. Neutrophils accumulation indicator myeloperoxidase was found to be reduced in colon tissue, while antioxidant enzymes like superoxide dismutase and glutathione peroxidase showed an increased activity. In vitro, the treatment with EGCG plus piperine enhanced the expression of SOD as well as GPO and also reduced the production of proinflammatory cytokines.. These data support the concept of anti-inflammatory properties of EGCG being generally beneficial in the DSS-model of colitis, an effect that may be mediated by its strong antioxidative potential.

Topics: Alkaloids; Analysis of Variance; Animals; Antioxidants; Benzodioxoles; Catechin; Colitis; Dextran Sulfate; Female; Glutathione Peroxidase; HT29 Cells; Humans; Interleukin-8; Malondialdehyde; Mice; Mice, Inbred C57BL; Oxidative Stress; Peroxidase; Piperidines; Polyunsaturated Alkamides; Reactive Oxygen Species; Superoxide Dismutase; Weight Loss

Chronic inflammation represents one of the hallmarks of cancer. Of special relevance to the malignant process is the pro-inflammatory cytokine IL-1 playing a crucial role in cancer-related inflammation. Recent observations indicate increased IL-1 levels in an animal model of human osteosarcoma, the most frequent primary malignant bone tumor in man. In patients with bone sarcomas, increased serum levels of tumor-promoting cytokines, including IL-6, IL-8 and VEGF can be found, correlating with poor overall survival. The link between cancer and inflammation makes it clear that there is a need to reduce the external factors inducing inflammation as a preventive or therapeutical measure. Therefore, in the present study the effects of anti-inflammatory IL-1 receptor antagonist (IL-1Ra) was tested alone and in combination with (-)-epigallocatechin-3-gallate (EGCG), an anti-inflammatory chemopreventive agent from green tea, on the production of IL-1-induced tumorigenic factors in U-2 OS human osteosarcoma cells. We found that IL-1Ra and EGCG downregulated IL-1-induced IL-6 and IL-8 release from U-2 OS cells by 65-85%. IL-1Ra and EGCG also reduced secretion of invasiveness-promoting MMP-2 and pro-angiogenic VEGF to 62-75% without affecting the metabolic response and caspase-3 activity. In conclusion, downregulation of IL-1-induced tumorigenic factors (IL-6, IL-8, VEGF, MMP-2) in U-2 OS by IL-1Ra and EGCG may positively affect tumor-associated inflammation and, as a consequence, lead to reduction in angiogenesis and invasiveness. This renders a combined administration of EGCG and IL-1Ra a promising approach as an adjuvant therapy in patients with osteosarcoma.

Topics: Antineoplastic Agents; Caspase 3; Catechin; Cell Line, Tumor; Cell Survival; Cell Transformation, Neoplastic; Drug Synergism; Enzyme Activation; Humans; Interleukin 1 Receptor Antagonist Protein; Interleukin-1; Interleukin-6; Interleukin-8; Matrix Metalloproteinase 2; Osteosarcoma; Receptors, Interleukin-1; Vascular Endothelial Growth Factor A

Acne vulgaris is the most common disease of the pilosebaceous unit. The pathogenesis of this inflammatory disease is complex, involving increased sebum production and perifollicular inflammation. To identify effective agents for factors that induce acne vulgaris, we explored the pharmacological potential of epigallocatechin-3-gallate (EGCG), which has been widely investigated as an anti-proliferative and anti-inflammatory agent. In this study, we demonstrated that topical application of EGCG to rabbit auricles reduced the size of the sebaceous glands. When applied to cultured human SZ95 sebocytes, EGCG strongly suppressed cell proliferation and lipogenesis. These actions of EGCG were reproduced in IGF-I-differentiated SZ95 sebocytes. To investigate the anti-inflammatory potential of EGCG, we evaluated pro-inflammatory cytokine synthesis in IGF-I-differentiated SZ95 sebocytes and found that expression of IL-1, IL-6, and IL-8 was decreased. These results provide early evidence that EGCG is an effective candidate for acne therapy whose mechanisms of action in IGF-I-differentiated SZ95 sebocytes include the inhibition of lipogenesis and inflammation.

Topics: Acne Vulgaris; Administration, Topical; Animals; Anti-Inflammatory Agents; Apoptosis; Catechin; Cell Line, Transformed; Cell Proliferation; Cytokines; Ear Auricle; Female; Humans; Insulin-Like Growth Factor I; Interleukin-1; Interleukin-6; Interleukin-8; Lipogenesis; Rabbits; Sebaceous Glands; Sebum; Signal Transduction

Epigallocatechin-3-gallate (EGCG) is a bioactive polyphenol of green tea and exerts potent anti-inflammatory effects by inhibiting signaling events and gene expression. Interleukin-1beta (IL-1β) is the principal cytokine linked to cartilage degradation in osteoarthritis (OA). The objective of this study was to evaluate the global effect of EGCG on IL-1β-induced expression of proteins associated with OA pathogenesis in human chondrocytes.. Primary OA chondrocytes were pretreated with EGCG (10 to 100 uM) and then stimulated with IL-1β (5 ng/ml) for 24 hours. Culture supernatants were incubated with cytokine antibody arrays and immunoreactive proteins (80 proteins) were visualized by enhanced chemiluminiscence. Effect of EGCG on IL-1β-induced expression of 18 selected genes was verified by Real time-PCR and effect on IL-6, IL-8 and tumor necrosis factor-alpha (TNF-α) production was determined using specific ELISAs. Western immunoblotting was used to analyze the effect of EGCG on the interleukin-1 receptor-associated kinase 1 (IRAK-1) and TNF receptor-associated factor 6 (TRAF-6) proteins in IL-1β-stimulated chondrocytes. The role of nuclear factor kappa-B (NF-κB) and mitogen activated protein kinases (MAPKs) in the regulation of selected genes and the mechanism involved in EGCG mediated modulation of these genes was determined by using specific inhibitors for NF- κB (MG132) and MAPKs (p38-MAPK, SB202190; JNK-MAPK, SP600125, ERK-MAPK, PD98059).. Out of 80 proteins present on the array, constitutive expression of 14% proteins was altered by EGCG treatment. No significant stimulatory effect was observed on the proteins associated with cartilage anabolic response. Stimulation with IL-1β enhanced the expression of 29 proteins. Expression of all 29 proteins up-regulated by IL-1β was found to be suppressed by EGCG. EGCG also inhibited the expression of the signaling intermediate TRAF-6 at 50 and 100 uM concentrations (P < 0.05). Our results identified several new targets of EGCG, including epithelial neutrophil activating peptide-78 (ENA-78), granulocyte macrophage colony stimulation factor (GM-CSF), growth- related oncogene (GRO), GRO-α, IL-6, IL-8, monocyte chemotactic protein-1 (MCP-1), MCP-3, macrophage inflammatory protein-1beta (MIP-1β), granulocyte chemotactic protein-2 (GCP-2), MIP-3alpha, interferon-gamma-inducible protein-10 (IP-10), nucleosome assembly protein-2 (NAP-2) and leukemia inhibitory factor (LIF). The inhibitory effects of EGCG were mainly mediated by inhibiting the activation of NF-κB and c-Jun N-terminal Kinase (JNK)-MAPK in human chondrocytes.. Our results suggest that the potential of EGCG in OA treatment/prevention may be related to its ability to globally suppress the inflammatory response in human chondrocytes. These results identify additional new targets of EGCG and advocate that EGCG may be a potent chondroprotective agent in OA.

Topics: Aged; Antioxidants; Catechin; Chondrocytes; Cytoprotection; Drug Interactions; Gene Expression; Humans; Intercellular Signaling Peptides and Proteins; Interleukin-1 Receptor-Associated Kinases; Interleukin-1beta; Interleukin-6; Interleukin-8; MAP Kinase Signaling System; Middle Aged; NF-kappa B; Nitrites; Osteoarthritis; Primary Cell Culture; TNF Receptor-Associated Factor 6; Tumor Necrosis Factor-alpha

In skin inflammation, vascular endothelial growth factor (VEGF) and CXCL-8/IL-8 play an important role and are produced by activated keratinocytes. Extracts from Ginkgo biloba leaves (GBE), widely used in phytotherapy, have been reported to exert antioxidant and anti-inflammatory properties in the skin. We therefore evaluated the effects of GBE on the release of VEGF and CXCL8/IL-8 by normal human keratinocytes (NHKs) activated by tumor necrosis factor alpha (TNFalpha). Moreover, as we previously showed that epigallocatechin-3-gallate (EGCG) reduces VEGF and CXCL8/IL-8 secretion in TNFalpha-activated NHKs, we also tested its effect in association with GBE. Our results showed that GBE exerted a potent inhibition on VEGF and CXCL8/IL-8 levels in activated cells. In association with EGCG, GBE down-regulated VEGF and CXCL8/IL-8 levels in a cumulative manner in TNFalpha-stimulated NHKs. These results suggest that GBE, alone or in association with EGCG may contribute to moderate inflammatory processes in skin diseases associated with angiogenesis.

Topics: Anti-Inflammatory Agents; Catechin; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Down-Regulation; Ginkgo biloba; Humans; Interleukin-8; Keratinocytes; Male; Plant Extracts; Plant Leaves; Time Factors; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A

The objective of this study was to examine the effects of (-)-epigallocatechin-3-gallate (EGCG) on cyclooxygenase 2 (COX-2), prostaglandin E(2) (PGE(2)), and interleukin 8 (IL-8) expression induced by IL-1beta in human synovial fibroblasts. Cells were enzymatically isolated from synovial tissue taken from patients undergoing joint replacement surgery for osteoarthritis. Reverse transcriptase-polymerase chain reaction, immunocytochemistry, and western blotting were used to assess the COX-2 gene and protein expression with the associated mechanisms. PGE(2) and IL-8 secretion into the culture medium was assayed by enzyme-linked immunosorbent assay. COX-2 upregulation in synovial fibroblasts induced by IL-1beta was significantly suppressed by EGCG in a dose-dependent manner. PGE(2) and IL-8 secretion was also induced by IL-1beta stimulation and significantly suppressed by EGCG. The mechanism was associated with the phosphorylation of IKKbeta. EGCG may inhibit the expression of inflammatory mediators, such as COX-2, PGE(2), and IL-8, induced by IL-1beta in human synovial fibroblasts. EGCG may be of value in the treatment of synovial inflammation.

Topics: Aged; Aged, 80 and over; Catechin; Cyclooxygenase 2; Enzyme-Linked Immunosorbent Assay; Fibroblasts; Genes; Humans; Interleukin-1beta; Interleukin-8; Middle Aged; Osteoarthritis; Prostaglandins E; Reverse Transcriptase Polymerase Chain Reaction; Synovial Membrane; Up-Regulation

Catechins (bioactive polyphenols in green tea) are known to exhibit potent anti-inflammatory properties. However, the anti-inflammatory effects of catechins on inflamed dental pulp tissue are not known. In this study, we investigated the effect of epigallocatechin-3-gallate (EGCG) and epicatechin gallate (ECG), the major components of green tea catechins, on the expression of pro-inflammatory cytokines and adhesion molecules in human dental pulp cells stimulated with bacteria-derived factors such as lipopolysaccharide (LPS) and peptidoglycan (PG). The expression of interleukin (IL)-6 and of IL-8 was examined using the reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assays. The expression of intercellular adhesion molecule-1 (ICAM-1) and of vascular cell adhesion molecule-1 (VCAM-1) on dental pulp cells was analyzed using flow cytometry. The presence of EGCG and ECG significantly reduced, in a concentration-dependent manner, the expression of IL-6 and IL-8 in dental pulp cells exposed to LPS or PG. Increased expression of ICAM-1 and VCAM-1 on the dental pulp cells in response to bacterial components was also decreased by treatment with EGCG and ECG. These findings suggest that green tea catechins may prevent the exacerbation of pulpitis.

Topics: Anti-Inflammatory Agents; Antioxidants; Catechin; Cells, Cultured; Dental Pulp; Escherichia coli; Flow Cytometry; Humans; Intercellular Adhesion Molecule-1; Interleukin-6; Interleukin-8; Lipopolysaccharides; Peptidoglycan; Reverse Transcriptase Polymerase Chain Reaction; Staphylococcus aureus; Time Factors; Vascular Cell Adhesion Molecule-1

Consumption of tea is associated with a reduced risk for several gastrointestinal cancers. Inflammatory processes, such as secretion of IL-8 from the gastric epithelium in response to chronic chemokine or antigen exposure, serve both as a chemoattractant for white blood cells and a prerequisite for gastric carcinogenesis. In this study, the gastric adenocarcinoma cell line AGS was used to investigate the effect of green tea extract, black tea extract, and epigallocatechin gallate (EGCG), the most abundant catechin in tea, on cytokine-induced inflammation. AGS cells were stimulated with interleukin-1β (IL-1β) to initiate inflammation, followed by exposure to either tea extracts or EGCG. We found that both green and black tea extracts at concentrations of 20 and 2 µM total catechins, respectively, significantly (p < 0.05) inhibited IL-1β-induced IL-8 production and secretion to a similar extent. Treatment of AGS cells with EGCG (8 µM) produced similar reductions in IL-1β-induced IL-8 production and secretion. Inhibition of NF-κB activity was found to be responsible, in part, for these observed effects. Our findings demonstrate that both green and black tea extracts with distinctly different catechin profiles, are capable of disrupting the molecular link between inflammation and carcinogenesis via inhibition of NF-κB activity in AGS cells.

Topics: Camellia sinensis; Catechin; Cell Line, Tumor; Chromatography, Liquid; Humans; Interleukin-1beta; Interleukin-8; MAP Kinase Signaling System; Mass Spectrometry; NF-kappa B; Plant Extracts; Stomach Neoplasms; Tea

Cholesterol and its oxidation products, namely oxysterols, have very recently been shown to potentially interfere with homeostasis of the human digestive tract, by promoting and sustaining irreversible damage of the colonic epithelial layer. This report concerns the strong proinflammatory action that a dietary oxysterol mixture and, to a lesser extent, an identical concentration of unoxidized cholesterol exert on CaCo-2 colonic epithelial cells by up-regulating both expression and synthesis of interleukin 8. The oxysterol mixture and its most effective component, 7β-hydroxycholesterol, are also shown to markedly enhance the expression of key inflammatory and chemotactic cytokines in colonic epithelial cells, more efficiently than unoxidized cholesterol. The sterols' proinflammatory effect seems to be mediated by enhanced activation of NOX1, because it is prevented by pretreatment of the cells with DPI, a selective inhibitor of this oxidase. Importantly, NOX1 hyperactivation by the oxysterol mixture or cholesterol was fully prevented by CaCo-2 cell preincubation with epigallocatechin-3-gallate. Consistently, supplementation with this compound fully protected colonic epithelial cells against overexpression of inflammatory and chemotactic genes induced by the sterols investigated.

Topics: Antioxidants; Apoptosis; Caco-2 Cells; Catechin; Cholesterol; Enterocytes; Enzyme Activation; Humans; Hydroxycholesterols; Inflammation Mediators; Interleukin-8; Ketocholesterols; NADPH Oxidases; Onium Compounds; Up-Regulation

Epigallocatechin-3-gallate (EGCG) is a major form of tea catechin and has a variety of biological activities. In the present study, we investigated the effect of EGCG on the secretion of TNF-alpha, IL-6 and IL-8, as well as its possible mechanism of action by using the human mast cell line (HMC-1).. EGCG was treated before the activation of HMC-1 cells with phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore (A23187). To investigate the effect of EGCG on PMA+A23187-stimulated HMC-1 cells, ELISA, Western blot analysis, electrophorectic mobility shift assay and luciferase assay were used in this study.. EGCG (100 microM) inhibited PMA+A23187-induced TNF-alpha, IL-6 and IL-8 expression and production. EGCG inhibited the intracellular Ca(2+) level. EGCG attenuated PMA+A23187-induced NF-kappaB and extracellular signal-regulated kinase (ERK1/2) activation, but not that of c-Jun N-terminal kinase or p38 mitogen-activated protein kinase.. EGCG inhibited the production of TNF-alpha, IL-6 and IL-8 through the inhibition of the intracellular Ca(2+) level, and of ERK1/2 and NF-kappaB activation. These results indicate that EGCG may be helpful in regulating mast-cell-mediated allergic inflammatory response.

Topics: Calcimycin; Calcium; Catechin; Cell Line, Tumor; Extracellular Signal-Regulated MAP Kinases; Humans; Interleukin-6; Interleukin-8; Ionophores; NF-kappa B; RNA, Messenger; Tetradecanoylphorbol Acetate; Tumor Necrosis Factor-alpha

Epigallocatechin-3-gallate (EGCG) is the major polyphenol component of green tea and is primarily responsible for the green tea effect. EGCG possesses two triphenolic groups in its structure. These groups are reported to be important with respect to anticarcinogenic and antioxidant effects. However, the anti-inflammatory effect of EGCG on Alzheimer's disease (AD) is still not fully understood. In this study, we investigated the effects of EGCG in attenuating the inflammatory response induced by interleukin (IL)-1beta+beta-amyloid (25-35) fragment (Abeta) in human astrocytoma, U373MG cells. EGCG significantly inhibited the IL-1beta+Abeta (25-35)-induced IL-6, IL-8, vascular endothelial growth factor (VEGF) and prostaglandin (PG)E(2) production at 24 h (P<.01). The maximal inhibition rate of IL-6, IL-8, VEGF and PGE(2) production by EGCG was approximately 54.40%, 56.01%, 69.06% and 47.03%, respectively. EGCG also attenuated the expression of cyclooxygenase-2 and activation of nuclear factor-kappaB induced by IL-1beta+Abeta (25-35). We demonstrated that EGCG suppresses IL-1beta+Abeta (25-35)-induced phosphorylation of the mitogen-activated protein kinase p38 and the c-Jun N-terminal kinase. In addition, EGCG induced the expression of mitogen-activated protein kinase phosphatase-1. These results provide new insight into the pharmacological actions of EGCG and its potential therapeutic application to various neurodegenerative diseases such as AD.

Topics: Amyloid beta-Peptides; Anti-Inflammatory Agents; Astrocytoma; Catechin; Cyclooxygenase 2; Dinoprostone; Humans; Interleukin-1beta; Interleukin-6; Interleukin-8; JNK Mitogen-Activated Protein Kinases; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Peptide Fragments; Phosphorylation; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A

A major component in green tea, epigallocatechin-3-gallate (EGCG), is reported to interfere with different steps of a number of inflammatory pathways. After oral administration, EGCG is retained in the gastrointestinal tract, where it is thought to exert preventive functions against inflammatory bowel disease and colon cancer. In this study, the human colon adenocarcinoma cell lines HT29 and T84 were used to investigate the effect of EGCG on intestinal inflammation. HT29 and T84 cells were stimulated with tumor necrosis factor (TNF)-alpha to induce the inflammatory condition and to trigger the inflammatory cascade in vitro and treated with EGCG to study its effect on inflammatory processes. The secretion of the chemokines interleukin (IL)-8, macrophage inflammatory protein (MIP)-3alpha, and prostaglandin E2 (PGE2) was determined by enzyme-linked immunosorbent assay. The gene expression level was measured by quantitative real-time polymerase chain reaction. Treatment of TNF-alpha-stimulated HT29 cells with EGCG dose-dependently inhibited the synthesis of IL-8, MIP-3alpha, and PGE2. Treatment with EGCG also inhibited the production of IL-8 and MIP-3alpha in TNF-alpha-stimulated T84 cells. Gene expression analysis in both HT29 and T84 cells revealed that EGCG down-regulates genes involved in inflammatory pathways. This study shows that EGCG acts broadly on the production of chemokines and PGE2 in the chemokine and eicosanoid pathways of colon epithelial cells. Therefore, EGCG might prove useful for the prevention and/or attenuation of colonic disorders.

Topics: Antioxidants; Catechin; Cell Line, Tumor; Cell Survival; Chemokines; Colon; Colonic Neoplasms; Dinoprostone; Enzyme-Linked Immunosorbent Assay; Epithelial Cells; HT29 Cells; Humans; Interleukin-8; Kinetics; Macrophage Inflammatory Proteins; Reverse Transcriptase Polymerase Chain Reaction; Tumor Necrosis Factor-alpha; Up-Regulation

Polyphenolic components of green tea, such as epigallocatechin-3-gallate (EGCG), have potent anti-inflammatory properties. We previously showed that EGCG inhibits tumor necrosis factor-alpha (TNF-alpha)-mediated activation of the nuclear factor-kappa B (NF-kappa B) pathway, partly through inhibition of I kappa B kinase (IKK). The NF-kappa B pathway may also be activated in response to interleukin-1 beta (IL-1 beta) stimulation through a distinct signal transduction pathway. We therefore hypothesized that EGCG inhibits IL-1 beta-mediated activation of the NF-kappa B pathway. Because the gene expression of interleukin-8 (IL-8), the major human neutrophil chemoattractant, is dependent on activation of NF-kappa B, IL-8 gene expression in human lung epithelial (A549) cells treated with human IL-1 beta was used as a model of IL-1 beta signal transduction. The EGCG markedly inhibited IL-1 beta-mediated IL-1 beta receptor-associated kinase (IRAK) degradation and the signaling events downstream from IRAK degradation: IKK activation, I kappa B alpha degradation, and NF-kappa B activation. In addition, EGCG inhibited phosphorylation of the p65 subunit of NF-kappa B. The functional consequence of this inhibition was evident by inhibition of IL-8 gene expression. Therefore, the green tea polyphenol EGCG is a potent inhibitor of IL-1 beta signal transduction in vitro. The proximal mechanisms of this effect involve inhibition of IRAK-dependent signaling and phosphorylation of p65.

Topics: Anti-Inflammatory Agents; Catechin; Cell Line, Tumor; Enzyme Activation; Flavonoids; Gene Expression Regulation; Humans; I-kappa B Kinase; Inflammation Mediators; Interleukin-1; Interleukin-1 Receptor-Associated Kinases; Interleukin-8; Isoenzymes; NF-kappa B; Phenols; Phosphorylation; Polyphenols; Protein Kinases; Protein Serine-Threonine Kinases; Respiratory Mucosa; Signal Transduction; Tea; Transcription Factor RelA

In skin inflammation, vascular endothelial growth factor (VEGF) and IL-8 play an important role and are produced by activated keratinocytes. Recently, some polyphenols have been reported to exhibit antiinflammatory and antiangiogenic properties. We therefore evaluated the effects of green tea, its major component epigallocatechin-3-gallate (EGCG) and an isoflavone derived from soybean (genistein) on the release of VEGF and IL-8 by activated normal human keratinocytes (NHK). NHK cultured in defined medium were stimulated for 48 h with the proinflammatory cytokine TNFalpha with the addition or not of different concentrations of polyphenols. Levels of VEGF and IL-8 were measured in cell supernatants by enzyme-linked immunosorbent assays. The different constituents tested inhibited keratinocyte proliferation without inducing apoptosis. They reduced in a dose-dependent manner the basal release and the upregulation of VEGF in NHK. Green tea and EGCG were also potent inhibitors of IL-8 release by TNFalpha-stimulated NHK, whereas genistein exerted only minor effects. These results underline the divergent pathways involved in the downregulation of VEGF and IL-8 by polyphenols in activated keratinocytes. They also suggest that polyphenols may contribute to moderate inflammatory processes in skin diseases associated with angiogenesis.

Topics: Angiogenesis Inhibitors; Catechin; Cell Division; Cells, Cultured; Down-Regulation; Genistein; Growth Inhibitors; Humans; Interleukin-8; Keratinocytes; Plant Extracts; Tea; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A

Interleukin-8 (IL-8) is a principle neutrophil chemoattractant and activator in humans. There is interest in developing novel pharmacological inhibitors of IL-8 gene expression as a means for modulating inflammation in disease states such as acute lung injury. Herein we determined the effects of epigallocatechin-3-gallate (EGCG), a green tea-derived polyphenol, on tumor necrosis factor-alpha (TNF-alpha)-mediated expression of the IL-8 gene in A549 cells. EGCG inhibited TNF-alpha-mediated IL-8 gene expression in a dose response manner, as measured by ELISA and Northern blot analysis. This effect appears to primarily involve inhibition of IL-8 transcription because EGCG inhibited TNF-alpha-mediated activation of the IL-8 promoter in cells transiently transfected with an IL-8 promoter-luciferase reporter plasmid. In addition, EGCG inhibited TNF-alpha-mediated activation of IkappaB kinase and subsequent activation of the IkappaB alpha/NF-kappaB pathway. We conclude that EGCG is a potent inhibitor of IL-8 gene expression in vitro. The proximal mechanism of this effect involves, in part, inhibition of IkappaB kinase activation.

Topics: Antioxidants; Catechin; Enzyme Activation; Flavonoids; Humans; I-kappa B Kinase; Interleukin-8; NF-kappa B; Phenols; Polymers; Protein Serine-Threonine Kinases; Respiratory Mucosa; RNA, Messenger; Tea; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha