Native Low-Density Lipoprotein-Dependent Interleukin-8 Production Through Pertussis Toxin-Sensitive G-Protein Coupled Receptors and Hydrogen Peroxide Generation Contributes to Migration of Human Aortic Smooth Muscle Cells

PURPOSE: Stimulation of human aortic smooth muscle cells (hAoSMCs) with native low-density lipoprotein (nLDL) induced the production of interleukin-8 (IL-8) that is involved in the pathogenesis of cardiovascular diseases. However, the process of signal transduction of nLDL was currently uncharacterized. Therefore, the aim of this study was to investigate the signal transduction pathway of nLDL-dependent IL-8 production and the effect of IL-8 on hAoSMCs migration. MATERIALS AND METHODS: nLDL was prepared by ultracentrifugation with density-adjusted human serum of normocholesterolemia. In hAoSMCs, IL-8 secreted to medium was measured using ELISA assay, and Western blot analysis was performed to detect p38 MAPK activation as a key regulator of IL-8 production. nLDL-dependent H2O2 generation was determined by microscopic analysis using 2',7'-dichlorofluoroscein diacetate (DCF-DA). IL-8-induced migration of hAoSMCs was evaluated by counting the cell numbers moved to lower chamber using Transwell plates. RESULTS: nLDL-induced IL-8 production was completely blocked by preincubation of hAoSMCs with pertussis toxin (PTX), which inhibited nLDL-dependent p38 MAPK phosphorylation. PTX-sensitive G-protein coupled receptor was responsible for nLDL-dependent H2O2 generation that was abrogated with preincubation of the cells with of polyethylene glycol-conjugated catalase (PEG-Cat). Pretreatment of PEG-Cat prevented nLDL-induced p38 MAPK phosphorylation and IL-8 production, which was partly mimicked by treatment with exogenous H2O2. Finally, IL-8 increased hAoSMCs migration that was completely blocked by incubation with IL-8 neutralizing antibody. CONCLUSION: PTX-sensitive G-protein coupled receptor-dependent H2O2 generation by nLDL plays a critical role in IL-8 production in hAoSMC, and IL-8 may contribute to atherogenesis through increased migration of hAoSMCs.

Grifola frondosa water extract alleviates intestinal inflammation by suppressing TNF-alpha production and its signaling

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.

LL-37 inhibits serum amyloid A-induced IL-8 production in human neutrophils

Serum amyloid A (SAA) has been regarded as an important mediator of inflammatory responses. The effect of several formyl peptide receptor-like 1 (FPRL1) ligands on the production of IL-8 by SAA was investigated in human neutrophils. Among the ligands tested, LL-37 was found to specifically inhibit SAA-induced IL-8 production in transcriptional and post-transcriptional levels. Since SAA stimulated IL-8 production via ERK and p38 MAPK in human neutrophils, we tested the effect of LL-37 on SAA induction for these two MAPKs. LL-37 caused a dramatic inhibition of ERK and p38 MAPK activity, which is induced by SAA. LL-37 was also found to inhibit SAA-stimulated neutrophil chemotactic migration. Further, the LL-37-induced inhibitory effect was mediated by FPRL1. Our findings indicate that LL-37 is expected to be useful in the inhibition of SAA signaling and for the development of drugs against SAA-related inflammatory diseases.

LL-37 inhibits serum amyloid A-induced IL-8 production in human neutrophils

Serum amyloid A (SAA) has been regarded as an important mediator of inflammatory responses. The effect of several formyl peptide receptor-like 1 (FPRL1) ligands on the production of IL-8 by SAA was investigated in human neutrophils. Among the ligands tested, LL-37 was found to specifically inhibit SAA-induced IL-8 production in transcriptional and post-transcriptional levels. Since SAA stimulated IL-8 production via ERK and p38 MAPK in human neutrophils, we tested the effect of LL-37 on SAA induction for these two MAPKs. LL-37 caused a dramatic inhibition of ERK and p38 MAPK activity, which is induced by SAA. LL-37 was also found to inhibit SAA-stimulated neutrophil chemotactic migration. Further, the LL-37-induced inhibitory effect was mediated by FPRL1. Our findings indicate that LL-37 is expected to be useful in the inhibition of SAA signaling and for the development of drugs against SAA-related inflammatory diseases.

A study on immunopathogenetic mechanisms of atherosclerotic process caused by chronic infection of Chlamydia pneumoniae in rats (Ratus novergicus).

AIM: this study was aimed to determine the correlations between duration of Chlamydia pneumoniae infection and the development of atherosclerotic process in white-rats' (Ratus novergicus) aorta. METHODS: this is an experimental study which examined the expression of TNFa, IL-1b, IL-8, adhesion molecule of VCAM-1 and the development of foam cells associated with atherosclerotic process in white-rats' aorta. There were 32 male rats, +/- 6 weeks of age, divided into 4 groups: control group (K) without infection, and 3 groups with infection through nasal and oral inoculation of Chlamydia pneumoniae by single dose of 5 x 105 in amount of 35 microl. The first group (P1) was preserved for 5(1/2) months period, the second group (P2) was preserved for 7(1/2) months and the third group (P3) was preserved for 9(1/2) months. At the end of study, histological slides were made from aortic tissues in order to study the development of atherosclerotic process by examining foam cells and cytokines expression of TNFa, IL-1b, IL-8 and VCAM-1. Foam cells examination was performed by Hematoxcillin-eosin staining, while indirect immunohistochemistry staining was used to examine the expression of TNFa, IL-1b, IL-8 and VCAM-1. Afterward, the amount of foam cells and cytokines expression was measured. The study result was analyzed by ANOVA. RESULTS: there was increased expression of TNFa, IL-1b, IL-8, VCAM-1and increased foam cells formation (extended atherosclerosis area) in the aortic tissues infected by Chlamydia pneumoniae (5(1/2) months, 7(1/2) months and 9(1/2) months), which was significantly different compared to the control group. The result of ANOVA revealed that the most important factor in tissue injury is foam cells development induced by VCAM-1 and IL-8 in all of phases (characterized by most abundant neutrophil infiltration). It indicated the infection caused by extracellular pathogenic agent, which established the fatty streak (acute phase) in 5(1/2) months period. In the group with 7(1/2) months infection period, TNFa also had important roles (characterized by increased monocytes and lymphocytes infiltration), indicating that there was negative-gram pathogenic agent with intracellular infection, which caused a progressive atherosclerotic process, and development of fibrosis / atherosclerotic plaque (sub acute phase). In 9(1/2) months infection period, there was large thrombus containing a lot of leukocytes in the aorta (chronic phase). CONCLUSION: based on the result of this study, it may be concluded that Chlamydia pneumoniae may cause atherosclerotic process in aorta. Extracellular infection of Chlamydia pneumoniae occurs in all of phases and intracellular infection begins in sub-acute phase. On 5(1/2) months period, fatty streak is developed (acute phase); on 7(1/2) months period, there is atherosclerotic plaque (sub acute phase); and on 9(1/2) period, there is large thrombus containing a lot of leukocytes (a progressive chronic phase).

Cytokine generation in stored platelet concentrate: comparison of two methods of preparation.

BACKGROUND & OBJECTIVES: Contaminating white blood cells (WBCs) in stored platelet concentrates (PC) are the main source of pro-inflammatory cytokines including interleukin-6 (IL-6), interleukin- 8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) that are implicated in transfusion reactions. We compared the levels of these cytokines in stored platelet preparations prepared by two methods. Effect of pre-storage leucofiltration on these cytokine levels was also studied. METHODS: Twelve units of pooled PCs were prepared by platelet rich plasma (PRP) method and buffy-coat (BC) method each and stored for 5 days. IL-6, IL-8 and TNF-alpha levels were measured in platelet supernatants on day 0, 1, 3 and 5 of the storage using commercially available immunoassays. Pre-storage leucofiltration was done in 4-pooled units of PRP-PC and cytokine levels compared with unfiltered PCs. RESULTS: Median IL-6 levels increased from day 0 to day 5 in both PRP-PC and BC-PC. In PRP-PC, IL-8 increased from <3 pg/ml on day 0 to 817 pg/ml on day 5, while in BC-PC the corresponding levels were 10 and 346.5 pg/ml, respectively. No significant increase in levels of TNF-alpha was observed in BC-PC during storage period, while levels increased significantly in PRP-PC on day 1 only. There was no significant change in the levels of all three cytokines in leucofiltered PCs over 5 days of storage. INTERPRETATION & CONCLUSION: Findings of our study showed that method of preparation and WBC content are the critical factors in determining the cytokine levels in stored PCs.

Effects of sonicated Prevotella intermedia, Fusobacterium nucleatum and Lactobacillus casei extracts on interleukin-8 production by human dental pulp cells.

The objective of this study was to determine the effects of Prevotella intermedia, Fusobacterium nucleatum and Lactobacillus casei on the production of IL-8 by human dental pulp cells. Human dental pulp cells from teeth of young patients (aged 18-25 years) were cultured and tested with sonicated P. intermedia ATCC 25611, F. nucleatum ATCC 25586 and L. casei ATCC 4646 extracts. IL-8 secreted into the culture supernatants were measured at 6, 12 and 24 hours using a quantitative sandwich enzyme immunoassay technique. Cell viability was evaluated using trypan blue exclusion technique. IL-8 production by human dental pulp cells increased significantly at 12 and 24 hours after exposure to P. intermedia and F. nucleatum, whereas L. casei extract exhibited low IL-8 production. The sonicated bacterial extracts did not significantly affect viability or total number of dental pulp cells.

CD137 induces adhesion and cytokine production in human monocytic THP-1 cells

CD137, which is expressed on activated T cells, plays a critical role in inflammatory responses. However, the exact role that CD137 plays in monocytes is not fully known. Here we studied the expression and function of CD137 in human monocytic THP-1 cells, which we found constitutively expresses CD137 at the mRNA and protein level. Cross-linking of CD137 increased the secretion of IL-8 and TNF-alpha, promoted the expression of CD54 and CD11b, and increased adhesion to extracellular matrix (ECM) proteins. In particular CD137-induced adhesion of THP-1 cells was inhibited by an inhibitor of mitogen-activated protein kinase kinase (MEK), but not by a p38 kinase inhibitor. Taken together, these results show that the adhesion and cytokine production of THP-1 cells induced by CD137 occur via activation of MEK, which results in the activation of ERK-1/2 signaling pathways. Therefore, this study suggests that CD137 induces an activating and migrating signal during inflammatory processes.

Production of pro-inflammatory cytokines [gm-csf, il-8 and il-6] by monocytes from fasciolosis patients

The production of proinflammatory cytokines by monocytes in vitro has been measured in eight patients with acute fascioliasis and 15 patients in the chronic stage of the disease before and after stimulation by excretory/secretory Fasciola antigen. The results were compared with those of a control group of 12 individuals. The monocytes from patients with acute fascioliasis produced significantly higher levels of GM-CSF, IL-8 and IL-6 as compared to controls. With chronicity, the production of these cytokines was decreased as compared to the acute stage probably due to decreased antigen level in blood. Stimulation of monocytes of healthy control with E/S Fasciola antigen was accompanied with a markedly increased production of proinflammatory cytokines, while monocytes from patients with acute or chronic fascioliasis revealed minimal increase in production. This denoted the importance of E/S Fasciola antigen as an activator of monocytes. A second exposure to the same antigen was accompanied with a limited response