The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. alpha-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether alpha-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-kappaB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without alpha-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-kappaB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-kappaB in AGS cells, which was inhibited by alpha-lipoic acid. In conclusion, alpha-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation.
Enzyme-Linked Immunosorbent Assay ; Epithelial Cells/metabolism ; Gastric Mucosa/*drug effects/metabolism/microbiology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/drug effects/*pathogenicity ; Humans ; Interleukin-8/genetics/*metabolism ; JNK Mitogen-Activated Protein Kinases ; Janus Kinase 1 ; Mitogen-Activated Protein Kinases/*biosynthesis ; NF-kappa B/*metabolism ; RNA, Messenger/isolation & purification/metabolism ; Reactive Oxygen Species/metabolism ; STAT3 Transcription Factor ; Stomach/metabolism/*microbiology ; Thioctic Acid/*pharmacology

Helicobacter pylori (H. pylori) induces the activation of nuclear factor-kB (NF-kappaB) and cytokine expression in gastric epithelial cells. The Janus kinase/signal transducers and activators of transcription (Jak/Stat) cascade is the inflammatory signaling in various cells. The purpose of the present study is to determine whether H. pylori-induced activation of NF-kappaB and the expression of interleukin-8 (IL-8) are mediated by the activation of Jak1/Stat3 in gastric epithelial (AGS) cells. Thus, gastric epithelial AGS cells were infected with H. pylori in Korean isolates (HP99) at bacterium/cell ratio of 300:1, and the level of IL-8 in the medium was determined by enzyme-linked immonosorbent assay. Phospho-specific and total forms of Jak1/Stat3 and IkappaBalpha were assessed by Western blot analysis, and NF-kappaB activation was determined by electrophoretic mobility shift assay. The results showed that H. pylori induced the activation of Jak1/Stat3 and IL-8 production, which was inhibited by a Jak/Stat3 specific inhibitor AG490 in AGS cells in a dose-dependent manner. H. pylori-induced activation of NF-kappaB, determined by phosphorylation of IkappaBalpha and NF-kappaB-DNA binding activity, were inhibited by AG490. In conclusion, Jak1/Stat3 activation may mediate the activation of NF-kappaB and the expression of IL-8 in H. pylori-infected AGS cells. Inhibition of Jak1/Stat3 may be beneficial for the treatment of H. pylori-induced gastric inflammation, since the activation of NF-kappaB is inhibited and inflammatory cytokine expression is suppressed.
Blotting, Western ; DNA, Bacterial/analysis/genetics ; Epithelial Cells/metabolism ; Gastric Mucosa/drug effects/*immunology/microbiology ; Gene Expression Regulation/drug effects/*immunology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/genetics/pathogenicity/*physiology ; Humans ; Interleukin-8/genetics/*metabolism ; Janus Kinase 1 ; NF-kappa B/biosynthesis/*metabolism ; Phosphorylation ; RNA, Messenger/metabolism ; STAT3 Transcription Factor ; Signal Transduction/genetics

Helicobacter pylori (H. pylori) induces the activation of nuclear factor-kB (NF-kappaB) and cytokine expression in gastric epithelial cells. The Janus kinase/signal transducers and activators of transcription (Jak/Stat) cascade is the inflammatory signaling in various cells. The purpose of the present study is to determine whether H. pylori-induced activation of NF-kappaB and the expression of interleukin-8 (IL-8) are mediated by the activation of Jak1/Stat3 in gastric epithelial (AGS) cells. Thus, gastric epithelial AGS cells were infected with H. pylori in Korean isolates (HP99) at bacterium/cell ratio of 300:1, and the level of IL-8 in the medium was determined by enzyme-linked immonosorbent assay. Phospho-specific and total forms of Jak1/Stat3 and IkappaBalpha were assessed by Western blot analysis, and NF-kappaB activation was determined by electrophoretic mobility shift assay. The results showed that H. pylori induced the activation of Jak1/Stat3 and IL-8 production, which was inhibited by a Jak/Stat3 specific inhibitor AG490 in AGS cells in a dose-dependent manner. H. pylori-induced activation of NF-kappaB, determined by phosphorylation of IkappaBalpha and NF-kappaB-DNA binding activity, were inhibited by AG490. In conclusion, Jak1/Stat3 activation may mediate the activation of NF-kappaB and the expression of IL-8 in H. pylori-infected AGS cells. Inhibition of Jak1/Stat3 may be beneficial for the treatment of H. pylori-induced gastric inflammation, since the activation of NF-kappaB is inhibited and inflammatory cytokine expression is suppressed.
Blotting, Western ; DNA, Bacterial/analysis/genetics ; Epithelial Cells/metabolism ; Gastric Mucosa/drug effects/*immunology/microbiology ; Gene Expression Regulation/drug effects/*immunology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/genetics/pathogenicity/*physiology ; Humans ; Interleukin-8/genetics/*metabolism ; Janus Kinase 1 ; NF-kappa B/biosynthesis/*metabolism ; Phosphorylation ; RNA, Messenger/metabolism ; STAT3 Transcription Factor ; Signal Transduction/genetics

TNF-alpha is a major cytokine involved in inflammatory bowel disease (IBD). In this study, water extract of Grifola frondosa (GFW) was evaluated for its protective effects against colon inflammation through the modulation of TNF-alpha action. In coculture of HT-29 human colon cancer cells with U937 human monocytic cells, TNF-alpha-induced monocyte adhesion to HT-29 cells was significantly suppressed by GFW (10, 50, 100 microg/ml). The reduced adhesion by GFW correlated with the suppressed expression of MCP-1 and IL-8, the major IBD-associated chemokines. In addition, treatment with GFW significantly suppressed TNF-alpha-induced reactive oxygen species production and NF-kappaB transcriptional activity in HT-29 cells. In differentiated U937 monocytic cells, LPS-induced TNF-alpha production, which is known to be mediated through NF-kappaB activation, was significantly suppressed by GFW. In an in vivo rat model of IBD, oral administration of GFW for 5 days (1 g/kg per day) significantly inhibited the trinitrobenzene sulfonic acid (TNBS)-induced weight loss, colon ulceration, myeloperoxidase activity, and TNF-alpha expression in the colon tissue. Moreover, the effect of GFW was similar to that of intra-peritoneal injection of 5-aminosalicylic acid (5-ASA), an active metabolite of sulfasalazine, commonly used drug for the treatment of IBD. The results suggest that GFW ameliorates colon inflammation by suppressing production of TNF-alpha as well as its signaling through NF-kappaB leading to the expression of inflammatory chemokines, MCP-1 and IL-8. Taken together, the results strongly suggest GFW is a valuable medicinal food for IBD treatment, and thus may be used as an alternative medicine for IBD.
Animals ; Cell Adhesion/drug effects/immunology ; Cell Extracts/administration & dosage/*pharmacology ; Chemokine CCL2/biosynthesis/genetics ; Coculture Techniques ; Colon/drug effects/*metabolism/pathology ; Grifola ; HT29 Cells ; Humans ; Inflammatory Bowel Diseases/chemically induced/*drug therapy/pathology/physiopathology ; Interleukin-8/biosynthesis/genetics ; Intestinal Mucosa/*drug effects/metabolism/pathology ; Monocytes/*drug effects/metabolism/pathology ; NF-kappa B/genetics/metabolism ; Peroxidase/metabolism ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species/metabolism ; Stomach Ulcer ; Transcription, Genetic/drug effects ; Trinitrobenzenesulfonic Acid/administration & dosage ; Tumor Necrosis Factor-alpha/*biosynthesis/genetics ; U937 Cells ; Weight Loss

OBJECTIVECytotoxin-associated protein (CagA) of H. pylori has been confirmed to be closely associated with gastric inflammation and tumorigenesis, but the mechanism behind it is little understood. In this study, we try to determine roles of CagA(+) strain in activating PI3K/Akt1 signaling pathway, and affecting expression of p21(WAF1/CIP1) and p27(KIP1), and also in releasing IL-8 in host cells.

METHODSAkt1 phosphorylation and IL-8 levels of CagA(+) and CagA⁻ strain infected AGS cells were detected by ELISAs. Two quantitative RT-PCRs were established to measure p21(WAF1/CIP1) and p27(KIP1) mRNA levels in the CagA(+) and CagA⁻ strain infected cells. LY294002, an inhibitor of PI3K/Akt pathway, was used to define effect of the pathway in IL-8 release.

RESULTSCagA(+) strain could induce an obvious elevation of Akt1 phosphorylation in the infected AGS cells while CagA? strain failed to do so. The CagA(+) H. pylori strain infected AGS cells showed significant drops both in p21(WAF1/CIP1) and p27(KIP1) mRNA levels, whereas the CagA⁻ H. pylori strain caused a remarkable increase in p21(WAF1/CIP1) mRNA without affecting p27(KIP1) gene transcription in the AGS cells. Both the CagA(+) and CagA⁻ H. pylori strains enabled AGS cells to produce close elevated levels of IL-8, and the LY294002 block resulted in unexpected elevations of IL-8 levels.

CONCLUSIONSCagA can activate PI3K/Akt1 pathway that plays an inhibitory role in IL-8 release in H. pylori infected AGS cells. Activation of PI3K/Akt1 pathway and subsequent negative regulation of p21(WAF1/CIP1) and p27(KIP1) expression might be involved in CagA-associated carcinogenesis.

Antigens, Bacterial ; genetics ; physiology ; Bacterial Proteins ; genetics ; physiology ; Cell Line ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; Cyclin-Dependent Kinase Inhibitor p27 ; Gastric Mucosa ; cytology ; enzymology ; microbiology ; Helicobacter pylori ; metabolism ; pathogenicity ; physiology ; Humans ; Interleukin-8 ; secretion ; Intracellular Signaling Peptides and Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Transcription, Genetic ; Virulence

BACKGROUND/AIMS: Angiogenesis, which is a critical step in the initiation and progression of rheumatoid arthritis (RA), involves pro-angiogenic factors, including interleukin (IL)-8 and vascular endothelial growth factor (VEGF). We investigated the role of Toll-like receptor 3 (TLR3) in the regulation of pro-angiogenic factors in RA fibroblast-like synoviocytes (FLS). METHODS: FLS were isolated from RA synovial tissues and stimulated with the TLR3 ligand, poly (I:C). The levels of VEGF and IL-8 in the culture supernatants were measured using enzyme-linked immunosorbent assays, and the mRNA levels were assessed by semiquantitative reverse transcription-polymerase chain reaction. The expression patterns of VEGF and IL-8 in the RA synovium and osteoarthritis (OA) synovium were compared using immunohistochemistry. RESULTS: The expression levels of TLR3, VEGF, and IL-8 were significantly higher in the RA synovium than in the OA synovium. VEGF and IL-8 production were increased in the culture supernatants of RA FLS stimulated with poly (I:C), and the genes for these proteins were up-regulated at the transcriptional level after poly (I:C) treatment. Treatment with inhibitors of nuclear factor-kappaB (NF-kappaB), i.e., pyrrolidine dithiocarbamate and parthenolide, abrogated the stimulatory effect of poly (I:C) on the production of VEGF and IL-8 in RA FLS. CONCLUSIONS: Our results suggest that the activation of TLR3 in RA FLS promotes the production of proangiogenic factors, in a process that is mediated by the NF-kappaB signaling pathway. Therefore, targeting the TLR3 pathway may be a promising approach to preventing pathologic angiogenesis in RA.
Arthritis, Rheumatoid/drug therapy/*etiology/metabolism ; Cells, Cultured ; Fibroblasts/metabolism ; Humans ; Interleukin-8/analysis/*biosynthesis/genetics ; NF-kappa B/physiology ; Neovascularization, Pathologic/etiology ; RNA, Messenger/analysis ; Synovial Membrane/cytology/*metabolism ; Toll-Like Receptor 3/analysis/*physiology ; Vascular Endothelial Growth Factor A/analysis/*biosynthesis/genetics

OBJECTIVETo investigate the mechanisms that coagulation factor VIIa promotes proliferation and migration of a colon cancer cell line (SW620 cells) in vitro.

METHODSThe expression of interleukin 8 (IL-8), tissue factor (TF), caspase-7 and p-p38 MAPK in SW620 cells treated with factor VIIa or protease activated receptor 2 agonist (PAR2-AP) was measured by ELISA, Western-blotting and QT-PCR.

RESULTSFactor VIIa and PAR2-AP induced IL-8 expression at both mRNA and protein levels, upregulated TF mRNA expression and TF activity, but down-regulated caspase-7 mRNA and p-p38 MAPK levels in SW620 cells. The effects of factor VIIa were not only blocked by anti-TF but also by anti-PAR2 antibodies.

CONCLUSIONFactor VIIa binds to TF on cell surface, forming a complex which activates PAR2, then provoking IL-8 and TF expression, and suppresses caspase-7 expression, thus promotes the tumor cell proliferation and migration. p38 MAPK may negatively regulate this process.

Caspase 7 ; biosynthesis ; genetics ; Cell Line, Tumor ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; metabolism ; pathology ; Factor VIIa ; pharmacology ; Humans ; Interleukin-8 ; biosynthesis ; genetics ; Oligopeptides ; pharmacology ; RNA, Messenger ; metabolism ; Receptor, PAR-2 ; agonists ; Thromboplastin ; biosynthesis ; genetics ; p38 Mitogen-Activated Protein Kinases ; metabolism

This study sought to elucidate whether Rac1 mediates the migration of endothelial cell induced by IL-8. The Transwell chamber motility assay was conducted to disclose the effect of different matrigel dilution and different time of IL-8 treatment on the migration of endothelial cells. The mRNA of Rac1 was detected by RT-PCR. The results demonstrated that when the concentration of Matrigel was 1:2, there is significant difference on the amounts of migration cells than that of the concentration of 1:3 or 1:8; When the dilution of Matrigel was 1:4, 1:5 or 1:6, there is no significant difference on the amounts of migration cells than that of other dilution groups. So we choose the Matrigel concentration as 1:4. With the increase of IL-8 stimulation time, the cells which migrated from upper reservoirs to lower reservoirs progressively increased. After six hours stimulation by IL-8, the expression of Rac1 mRNA in migrated cells was increased, compared with that of other groups. The results suggest that Rac1 may mediate the migration of endothelial cells induced by IL-8. It can also be the foundation for further investigation on the role of Rac1 in the migration of endothelial cells induced by IL-8.
Cell Movement ; drug effects ; Cells, Cultured ; Endothelial Cells ; cytology ; metabolism ; Humans ; Interleukin-8 ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; Umbilical Veins ; cytology ; metabolism ; rac1 GTP-Binding Protein ; biosynthesis ; genetics

OBJECTIVETo study the expression change of interleukin-8 (IL-8) gene in the basilar artery of rabbit and the effect of IL-8 on the development of cerebral vasospasm induced by experimental subarachnoid hemorrhage (SAH).

METHODSThirty five healthy Japanese White Rabbits were randomly divided into saline-control group and experimental group. The experimental group was subdivided into four groups, representing day 1, 4, 7 and 14 after the first blood injection of SAH. The delayed cerebral vasospasm (DCVS) model was established by double injection of autologous blood into the cisterna magna. The expression change of cytokine IL-8 mRNA in the basilar artery was analyzed by RTPCR.

RESULTSThe expression of IL-8 gene increased on day 4-7 after the first blood injection of SAH compared with control (P< 0.001), and decreased to normal on day 14. The expression of IL-8 gene in the SAH groups were positively correlated with the degree of basilar artery stenosis (r = 0.642, P< 0.01).

CONCLUSIONThe expression level of IL-8 gene in basilar arteries was intimately associated with the degree of cerebral vasospasm, suggesting that IL-8 may play an important role in the DCVS after SAH as an immunological inflammatory factor.

Animals ; Basilar Artery ; metabolism ; Disease Models, Animal ; Gene Expression Regulation ; physiology ; Interleukin-8 ; genetics ; metabolism ; RNA, Messenger ; biosynthesis ; Rabbits ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Subarachnoid Hemorrhage ; metabolism ; pathology ; Time Factors

To investigate whether lithium carbonate, propranolol or chloroquine aggravate psoriasis through influencing cytokines of the psoriatic cytokine network, HaCaT keratinocytes were stimulated with TNF-a after treatment with these drugs. Protein secretion of a set of multiple different cytokines and growth factors in culture supernatants were measured by using a cytokine antibody array technology. Expression of IL-8 and IL-6 mRNA was determined by real-time PCR. In culture supernatants of TNF-alpha-stimulated HaCaT cells, production of IL-6 and TNF-alpha could be enhanced by lithium carbonate; production of IL-6 and a panel of cytokines and growth factors could be enhanced by propranolol hydrochloride; and IL-6 was up-regulated by chloroquine diphosphate as well. Real-time PCR analysis showed a significantly dose-dependent increase of IL-8 and IL-6 mRNA expression in HaCaT cells stimulated with TNF-a as compared to cells without TNF-alpha-stimulation, the mRNA expression of IL-8 was higher than that of IL-6 with the same concentration of TNF-alpha (P < 0.01). Compared with HaCaT cells cultured with medium alone, propranolol hydrochloride at the concentration of 1 x 10(-6) mol x L(-1) could stimulate HaCaT cells to express higher level of IL-6 mRNA (P < 0.05). The drugs investigated show a modulatory effect on certain cytokines and growth factors which are able to modulate inflammatory type of immune reaction present in psoriatic lesions.
Adrenergic beta-Antagonists ; adverse effects ; Antimalarials ; adverse effects ; Cells, Cultured ; Chloroquine ; adverse effects ; analogs & derivatives ; Humans ; Interleukin-6 ; biosynthesis ; genetics ; Interleukin-8 ; biosynthesis ; genetics ; Keratinocytes ; drug effects ; metabolism ; Lithium Carbonate ; adverse effects ; Propranolol ; adverse effects ; Psoriasis ; metabolism ; RNA, Messenger ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology