Lipopolysaccharide-induced Interleukin-6 Production Research Articles

Gabapentinoids Suppress Lipopolysaccharide-Induced Interleukin-6 Production in Primary Cell Cultures of the Rat Spinal Dorsal Horn

Introduction: Gabapentin and pregabalin are drugs to treat neuropathic pain. Several studies highlighted effects on presynaptic terminals of nociceptors. Via binding to α₂δ subunits of voltage-gated calcium channels, gabapentinoids modulate the synaptic transmission of nociceptive information. However, recent studies revealed further properties of these substances. Treatment with gabapentin or pregabalin in animal models of neuropathic pain resulted not only in reduced symptoms of hyperalgesia but also in an attenuated activation of glial cells and decreased production of pro-inflammatory mediators in the spinal dorsal horn. Methods: In the present study, we aimed to investigate the impact of gabapentinoids on the inflammatory response of spinal dorsal horn cells, applying the established model of neuro-glial primary cell cultures of the superficial dorsal horn (SDH). We studied effects of gabapentin and pregabalin on lipopolysaccharide (LPS)-induced cytokine release (bioassays), expression of inflammatory marker genes (RT-qPCR), activation of transcription factors (immunocytochemistry), and Ca²⁺ responses of SDH neurons to stimulation with substance P and glutamate (Ca²⁺-imaging). Results: We detected an attenuated LPS-induced expression and release of interleukin-6 by SDH cultures in the presence of gabapentinoids. In addition, a significant main effect of drug treatment was observed for mRNA expression of microsomal prostaglandin E synthase 1 and the inhibitor of nuclear factor kappa B. Nuclear translocation of inflammatory transcription factors in glial cells was not significantly affected by gabapentinoid treatment. Moreover, both substances did not modulate neuronal responses upon stimulation with substance P or glutamate. Conclusion: Our results provide evidence for anti-inflammatory capacities of gabapentinoids on the acute inflammatory response of SDH primary cultures upon LPS stimulation. Such effects may contribute to the pain-relieving effects of gabapentinoids.

1,25-Dihydroxyvitamin D3 Inhibits Lipopolysaccharide-Induced Interleukin-6 Production by C2C12 Myotubes

Background and Objective: 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) inhibits proinflammatory cytokines in microglial cells and monocytes. However, it is unclear whether 1,25(OH)2D3 inhibits proinflammatory cytokines in muscle cells. This study was conducted to investigate whether 1,25(OH)2D3 inhibits the production of proinflammatory cytokines, resulting in inhibition of the protein expression of E3 ubiquitin ligases and muscle protein loss. Materials and Methods: C2C12 myoblasts were proliferated in Dulbecco’s modified Eagle medium (DMEM) containing 10% fetal bovine serum, and myoblasts were differentiated into myotubes in DMEM containing 2% horse serum. Myotubes were treated with 1,25(OH)2D3 for 24 h, followed by lipopolysaccharide (LPS) stimulation for 48 h. Results: Interleukin (IL)-6 protein concentrations were higher in the culture supernatant following LPS stimulation compared to that without LPS stimulation (p < 0.001). However, the IL-6 concentration was significantly lower in C2C12 myotubes following 1,25(OH)2D3 treatment than in C2C12 myotubes without 1,25(OH)2D3 treatment (p < 0.001). The myosin heavy chain (MHC), muscle atrophy F-box, and muscle ring-finger protein-1 protein levels did not significantly differ (P = 0.324, 0.552, and 0.352, respectively). We could not compare tumor necrosis factor α (TNFα) protein levels because they were below the limit of detection of our assay in many supernatant samples, including in LPS-stimulated samples. Conclusions: 1,25(OH)2D3 inhibited increases in IL-6 protein concentrations in muscle cells stimulated by LPS, suggesting that 1,25(OH)2D3 inhibits inflammation in muscle cells. The findings suggest that 1,25(OH)2D3 can prevent or improve sarcopenia, which is associated with IL-6. The TNFα protein content could not be measured, and MHC was not decreased despite LPS stimulation of C2C12 myotubes. Further studies are needed to examine the effects of higher doses of LPS stimulation on muscle cells and use more sensitive methods for measuring TNFα protein to investigate the preventive effects of 1,25(OH)2D3 on increased TNFα and muscle proteolysis.

Anti-inflammatory Effects of Sargachromanol I, Sargachromanol G, and Saringosterol from Hexane Fraction of Myagropsis myagroides

The anti-inflammatory activity of benzopyran derivatives extracted from the Myagropsis myagroides against lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophage cell line was examined. The three constituents of M. myagroides extracts were identified as the sargachromanol G, sargachromanol I, and saringosterol by 1H and 13C NMR. Sargachromanol G, sargachromanol I, and saringosterol at concentrations of 50 μg/mL showed inhibitory effects on LPS induced interleukin-6 production (by 84%, 90%, and 96%, respectively) and tumor necrosis factor (by 74%, 82%, and 98%, respectively). These results confirm the potential anti-inflammatory effects of sarga-chromanol G, sargachromanol I, and saringosterol.

1,25-dihydroxyvitamin D3 suppresses lipopolysaccharide-induced interleukin-6 production through aryl hydrocarbon receptor/nuclear factor-\u03baB signaling in oral epithelial cells

BackgroundAntiinflammatory effect of 1,25-dihydroxyvitamin D3 (1,25D3) has been reported in periodontitis, but the exact mechanisms remain unclear. Oral epithelial cells are recently highlighted as an important regulator of inflammation in this disease. This in vitro study was established to investigate the effect of 1,25D3 on key proinflammatory cytokine IL-6 production and aryl hydrocarbon receptor (AhR)/nuclear factor-κB (NF-κB) signaling in oral epithelial cells upon the stimulation of lipopolysaccharide (LPS) from periodontal pathogens.MethodsOKF6/TERT-2 oral keratinocytes were incubated with LPS and different concentrations of 1,25D3, and levels of IL-6 production were determined using enzyme-linked immunosorbent assay (ELISA). Expression of vitamin D receptor (VDR), and activation of AhR was examined using western blot analysis, and phosphorylation of NF-κB was detected using cell-based protein phosphorylation ELISA.Results1,25D3 inhibited LPS-induced IL-6 overexpression in OKF6/TERT-2 cells. Additionally, 1,25D3 increased VDR expression and AhR activation, and repressed NF-κB phosphorylation. Furthermore, 1,25D3 suppressed IL-6 expression and enhanced VDR expression and regulated AhR/NF-κB signaling activation in a dose-dependent manner after 48 h treatment.ConclusionsThese results suggest that 1,25D3 may inhibit LPS-induced IL-6 overexpression in human oral epithelial cells through AhR/NF-κB signaling. Our findings may provide an explanation for the antiinflammatory effect and therapeutic benefit of 1,25D3 in periodontitis.

Lipopolysaccharide induced Interleukin-6 production is mediated through activation of ERK 1/2, p38 MAPK, MEK, and NFκB in chicken thrombocytes

Thrombocytes express Toll-like receptor 4 and apparently use both mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB) pathways for nuclear signaling. However, it is not well known if the same enzyme systems found in mammalian cells are fully functional in chickens. Therefore, kinase inhibitors were used with thrombocytes to block kinases in lipopolysaccharide (LPS) stimulated cells to determine if interleukin (IL)-6 expression and production would be diminished. Results demonstrated that extracellular-signal-regulated kinase (ERK)1/2 and p38 MAPK pathways influence gene expression of IL-6 through treatment with either ERK or p38 MAPK inhibitor. In addition, thrombocyte lysates from cells treated with ERK, p38, mitogen-activated protein kinase kinase (MEK)1/2 and inhibitor of nuclear factor kappa-B kinase (IKK) inhibitor showed different levels of the phosphorylated form of ERK1/2, p38 and NFκB. Furthermore, IL-6 gene expression and production were significantly upregulated in LPS stimulated thrombocytes relative to all inhibitor-treated cells.

GPR120 in adipocytes has differential roles in the production of pro-inflammatory adipocytokines

How nutritional excess leads to inflammatory responses in metabolic syndrome is not well characterized. Here, we evaluated the effects of ω-3 polyunsaturated fatty acid specific G-protein coupled receptor 120 (GPR120) activation on inflammatory pathways in adipocytes, and the influence of this process on macrophage migration. Using 3T3-L1 adipocytes, we found that agonizing GPR120 using its synthetic ligand, GSK137647, attenuated both basal and lipopolysaccharide-induced production of interleukin-6 (IL-6) and C-C motif chemokine ligand 2 (CCL2). Moreover, the intervention reduced the phosphorylation of nuclear factor kappa B inhibitor alpha (IκBα) and nuclear translocation of nuclear factor kappa-B p65 subunit (p65). Furthermore, the silencing of GPR120 itself reduced IL-6 and CCL2 mRNA expression. Inhibition of protein kinase C (PKC) augmented the down-regulatory effect of GSK137647 on IL-6 and CCL2 mRNA. Using a luciferase assay to measure promoter activity of the IL-6 gene in mouse embryonic fibroblasts, we demonstrated that exogenous transfection of GPR120 alone reduced the promoter activity, which was augmented by GSK137647. Inhibition of PKC further reduced the promoter activity. Nevertheless, RAW 264.7 macrophages grown in conditioned medium collected from GSK137647-treated adipocytes attenuated the expressions of matrix metalloproteinases-9 and -3, and tissue inhibitor of metalloproteinase-1. Conditioned medium also inhibited the lipopolysaccharide-induced migration of these macrophages. Taken together, these findings provide critical evidence that although GPR120 is associated with a PKC-mediated pro-inflammatory pathway, the direct inhibitory effects of GPR120 on the nuclear factor kappa B pathway are anti-inflammatory. Moreover, GPR120 activity can attenuate the adipocyte-mediated enhanced production of extracellular matrix-modulating factors in macrophages and can reduce their migration by a paracrine mechanism.

Mangiferin inhibits lipopolysaccharide-induced production of interleukin-6 in human oral epithelial cells by suppressing toll-like receptor signaling

ObjectiveOral epithelial cells have currently been found to play an important role in inflammatory modulation in periodontitis. Mangiferin is a natural glucosylxanthone with anti-inflammatory activity. The aim of this study was to investigate the regulatory effect of mangiferin on lipopolysaccharide (LPS)-induced production of proinflammatory cytokine interleukin-6 (IL-6) in oral epithelial cells and the underlying mechanisms. DesignThe levels of LPS-induced IL-6 production in OKF6/TERT-2 oral keratinocytes were detected using enzyme-linked immunosorbent assay (ELISA). The expression of Toll-like receptor (TLR) 2 and TLR4 was determined using western blot analysis. And the phosphorylation of TLR downstream nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK) was examined using cell-based protein phosphorylation ELISA kits. ResultsWe found that mangiferin reduced LPS-upregulated IL-6 production in OKF6/TERT-2 cells. Additionally, mangiferin inhibited LPS-induced TLR2 and TLR4 overexpression, and suppressed the phosphorylation of NF-κB, p38 MAPK and JNK. Moreover, mangiferin repressed IL-6 production and TLR signaling activation in a dose-dependent manner after 24h treatment. ConclusionsMangiferin decreases LPS-induced production of IL-6 in human oral epithelial cells by suppressing TLR signaling, and this glucosylxanthone may have potential for the treatment of periodontitis.

Nickel ions selectively inhibit lipopolysaccharide-induced interleukin-6 production by decreasing its mRNA stability.

Nickel (Ni) ions easily elute from many alloys and elicit inflammation and allergies. Previous studies have shown that infections due to the implantation of medical devices cause inflammation and enhance the elution of Ni ions (Ni2+). However, cross-talk between infection- and Ni2+-induced signaling pathways has not yet been elucidated in detail. In the present study, we investigated the effects of Ni2+ on the lipopolysaccharide (LPS)-induced production of cytokines in a LPS-induced air pouch-type inflammation model in BALB/c mice and the murine macrophage cell line RAW264. We demonstrated that Ni2+ inhibited the LPS-induced production of interleukin (IL)-6, but not that of tumor necrosis factor (TNF)-α both in vivo and in vitro. This inhibitory effect was also observed with cobalt ion (Co2+), but not with chloride ion (Cl-), zinc ion (Zn2+), or palladium ion (Pd2+), and was highly selective to the production of IL-6. Ni2+ did not inhibit the activation of ERK1/2, p38 MAPK, or JNK. Although Ni2+ decreased IL-6 mRNA levels, it failed to inhibit the LPS-induced activation of the IL-6 promoter. An experiment using actinomycin D, a transcription inhibitor, revealed that Ni2+ decreased the stability of IL-6 mRNA. Moreover, Ni2+ inhibited the LPS-induced expression of Arid5a, but not regnase-1. These results demonstrated that Ni2+ may have selectively inhibited the LPS-induced production of IL-6 by decreasing the Arid5a-dependent stabilization of IL-6 mRNA.

Effect of azithromycin on Prevotella intermedia lipopolysaccharide-induced production of interleukin-6 in murine macrophages

Interleukin-6 (IL-6) is a key proinflammatory cytokine which plays a central role in the pathogenesis of periodontal disease. Host modulatory agents targeting at inhibiting IL-6, therefore, appear to be beneficial in slowing the progression of periodontal disease and potentially reducing destructive aspects of the host response. The present study was designed to investigate the effect of the macrolide antibiotic azithromycin on IL-6 generation in murine macrophages treated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action. Azithromycin significantly suppressed IL-6 production as well as its mRNA expression in P. intermedia LPS-activated RAW264.7 cells. LPS-induced activation of JNK and p38 was not affected by azithromycin treatment. Azithromycin failed to prevent P. intermedia LPS from degrading IκB-α. Instead, azithromycin significantly diminished nuclear translocation and DNA binding activity of NF-κB p50 subunit induced with LPS. Azithromycin inhibited P. intermedia LPS-induced STAT1 and STAT3 phosphorylation. In addition, azithromycin up-regulated the mRNA level of SOCS1 in cells treated with LPS. In conclusion, azithromycin significantly attenuated P. intermedia LPS-induced production of IL-6 in murine macrophages via inhibition of NF-κB, STAT1 and STAT3 activation, which is possibly related to the activation of SOCS1 signaling. Further in vivo studies are required to better evaluate the potential of azithromycin in the treatment of periodontal disease.

Differential effects of low and high doses of lipoteichoic acid on lipopolysaccharide-induced interleukin-6 production

Interleukin-6 (IL-6), which is increased in patients who are suffering from septic shock, is an important mediator of the inflammatory response. Here, we examined the priming effect of lipoteichoic acid (LTA) and lipopolysaccharide (LPS) on IL-6 production in a monocyte-like cell line. THP-1 cells were primed by treatingwith a low or high dose of LTA isolated from Staphylococcus aureus (aLTA) and then re-treated with LPS. IL-6 production, receptor expression, and the variation of signaling molecules were examined by ELISA, reverse transcriptase polymerase chain reaction, and western blotting, respectively. LPS-mediated IL-6 production was dramatically increased in THP-1 cells pretreated with a low dose aLTA, while it was significantly decreased when a high dose of aLTA was given along with LPS. LPS-induced IL-6 production in low dose aLTA priming cells mediated by NF-κB and MAPKs pathways, and Akt functioned as a negative regulator of IL-6 production. Together, the results of this study suggest that different doses of bacterial cell surface components can mediate a diverse range of responses with respect to inflammatory cytokine production.

Maleylated-BSA suppresses lipopolysaccharide-induced IL-6 production by activating the ERK-signaling pathway in murine RAW264.7 cells

Macrophages are well known for their ability to induce diverse beneficial immune responses, especially in the defense against pathogens. However, an excessive activation of macrophages may cause harmful inflammation. In this context, the suppression of excessive macrophage activation would be a promising therapeutic strategy for treating inflammatory diseases. We have previously found that maleylated-bovine serum albumin (maleylated-BSA) suppresses the production of inflammatory mediators in murine macrophages. However, the immunosuppressive effects and underlying mechanism(s) of maleylated-BSA remain unclear. Here, we report that pretreatment with maleylated-BSA strongly inhibited the production of interleukin 6 (IL-6) induced by bacterial lipopolysaccharide (LPS) in murine RAW264.7 cells. This inhibitory effect of maleylated-BSA on LPS-induced IL-6 production was eliminated by treatment with an extracellular signal-regulated kinase (ERK) inhibitor, U0126, indicating the involvement of ERK pathways. Taken together, we have shown that maleylated-BSA suppresses LPS-induced production of IL-6 via the activation of an ERK signaling pathway in murine macrophages. The findings of this study imply the possibility of a novel therapeutic strategy for inflammatory diseases.

Glucocorticoid inhibition of leptin- and lipopolysaccharide-induced interleukin-6 production in obesity

Obesity is considered a chronic inflammatory condition that enhances the risk of numerous inflammatory diseases, including diabetes and cardiovascular disease. Glucocorticoids (GCs) and synthetic therapeutic GCs are anti-inflammatory agents, but the exact functions of GCs in obesity-related inflammation are unknown. Therefore, the objective of this study was to examine the inhibitory effect of an exogenous GC (dexamethasone, DEX) on leptin- and lipopolysaccharide (LPS)-induced IL-6 production by peripheral blood mononuclear cells (PBMCs) ex vivo in obese subjects compared to normal-weight subjects. Blood samples were drawn from 14 obese (BMI>30 kg/m(2)) and 14 normal-weight (BMI<25 kg/m(2)) subjects. Plasma cortisol, TNF-α and IL-6 levels, and insulin resistance (HOMA-IR) were quantified. Subjects' PBMCs (1×10(6) cells/mL) were isolated and cultured with leptin (18.75 and 250 ng/mL) or LPS (10ng/mL) in the presence of DEX (0, 10(-8), 10(-7), and 10(-6) M), a synthetic GC, for 24 h; IL-6 levels and GC sensitivity (IC50) were assessed in the cultured supernatants. No differences in the plasma cortisol levels were found between the two groups. We found that obese subjects showed greater leptin- and LPS-induced IL-6 production compared to normal-weight subjects. The suppressive effect of DEX on leptin- and LPS-induced IL-6 production (IC50) was not different between the two groups. However, the IC50 of DEX for LPS-induced was correlated with BMI, waist circumference, and hip circumference. These findings suggest that reduced GC sensitivity may be an important mechanism in the up-regulation of selected obese inflammation.

Combination of midazolam and a cyclooxygenase-2 inhibitor inhibits lipopolysaccharide-induced interleukin-6 production in human peripheral blood mononuclear cells

Context: Interleukin-6 (IL-6) plays an important role in immune and inflammatory responses. Midazolam has been reported to modulate IL-6 response. Cyclooxygenase (COX) inhibitors, which are used together with midazolam in some patients undergoing surgery, also modulate it. We hypothesized that their combination results in eliciting the synergistical effect on the IL-6 response.Objective: The aim of the present study was to evaluate the effect of the combination of midazolam and a COX inhibitor on IL-6 production.Materials and methods: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy volunteers and incubated with lipopolysaccharide (LPS), midazolam, and/or COX inhibitors, including indomethacin, SC-560, a COX-1 selective inhibitor, and NS-398, a COX-2 selective inhibitor. The supernatant concentrations of IL-6 and prostaglandins (PGs), including PGE2, PGF2α, PGD2, and 15-deoxy-Δ12,14-prostaglandin J2 (15dPGJ2) were measured.Results: Midazolam had no effect on IL-6 production in the cells incubated for 12 h, and any COX inhibitors also had no effect. However, the combination of midazolam and NS-398 significantly inhibited it. Midazolam raised the concentration of 15dPGJ2 in the supernatant of the cells, but not the concentration of other PGs.Disscussion and conclusion: The results in the present study demonstrated that the combination of midazolam and a COX-2 inhibitor inhibited LPS-induced IL-6 production in human PBMCs even if each drug separately did not have any effect on it. The finding suggests that their combination is effective against excessive IL-6 production such as severe inflammatory response and that the effect of midazolam on IL-6 production is possibly elicited via 15dPGJ2.

The functional Toll-like receptor 4 Asp299Gly polymorphism is associated with lower left ventricular mass in hypertensive women

Background This study investigated the impact of a putative functional TLR4 polymorphism (Asp299Gly) on left ventricular (LV) structure in hypertensive subjects. Methods A sample of 443 patients (266 women and 177 men) was evaluated by clinical history, physical examination, anthropometry, analysis of inflammatory and metabolic parameters, echocardiography and TLR4 Asp299Gly genotyping. In addition, the relationship between the polymorphism and in vitro lipopolysaccharide responsiveness of peripheral blood monocytic cells was also assessed. Results Women carrying the 299Gly allele presented lower posterior wall thickness ( p = 0.01), interventricular septum thickness ( p = 0.04), LV mass ( p = 0.01) and LV mass index ( p = 0.03), as well as a reduced prevalence of LV hypertrophy ( p = 0.002), in comparison to women with the wild-type genotype. These results were confirmed by stepwise and logistic regression analyses adjusted for potential confounders. Conversely, the 299Gly allele did not influence LV structure in men. Furthermore, in vitro assays revealed that monocytes of either men or women heterozygous for the 299Gly allele presented a lower lipopolysaccharide-induced production of interleukin-6, compared to non-carriers. Conclusions The functional TLR4 Asp299Gly polymorphism is associated with lower LV mass in hypertensive women. These findings suggest that interactions among gender, LV remodeling and TLR4 gene variants may occur in hypertensive subjects.

Lipopolysaccharide-induced interleukin-6 production is controlled by glycogen synthase kinase-3 and STAT3 in the brain

BackgroundSeptic shock is a prevalent condition that, when not lethal, often causes disturbances in cognition, mood, and behavior, particularly due to central actions of the inflammatory cytokine interleukin-6 (IL-6). To identify potential targets to control brain IL-6, we tested if IL-6 produced by glia is regulated by signal transducer and activator of transcription-3 (STAT3) and glycogen synthase kinase-3 (GSK3).MethodsLipopolysaccharide (LPS) was used to induce inflammatory responses in mice or cultured primary glia. IL-6 was measured by ELISA and other inflammatory molecules were measured using an array.ResultsMouse brain IL-6 levels increased after central, as well as peripheral, LPS administration, consistent with glia producing a portion of brain IL-6. STAT3 in the brain was activated after peripheral or central LPS administration, and in LPS-stimulated cultured primary glia. Inhibition of STAT3 expression, function, or activation reduced by ~80% IL-6 production by primary glia, demonstrating the dependence on active STAT3. GSK3 promotes STAT3 activation, and array analysis of inflammatory molecules produced by LPS-stimulated primary glia demonstrated that IL-6 was the cytokine most diminished (>90%) by GSK3 inhibition. Inhibition of GSK3, and knockdown of GSK3β, not GSK3α, greatly inhibited IL-6 production by LPS-stimulated primary glia. Conversely, expression of active STAT3 and active GSK3 promoted IL-6 production. In vivo inhibition of GSK3 reduced serum and brain IL-6 levels, brain STAT3 activation, and GFAP upregulation following LPS administration.ConclusionSTAT3 and GSK3 cooperatively promote neuroinflammation, providing novel targets for anti-inflammatory intervention.

Effect of Adiponectin on Murine Colitis Induced by Dextran Sulfate Sodium

Adiponectin, an adipose tissue-derived hormone, exhibits anti-inflammatory properties and has various biological functions, such as increasing insulin sensitivity, reducing hypertension, and suppressing atherosclerosis, liver fibrosis, and tumor growth. The aim of the present study was to determine the effect of adiponectin on intestinal inflammation. We investigated the effect of adiponectin on dextran sulfate sodium (DSS)-induced colitis by using adiponectin-knockout (APN-KO) mice and an adenovirus-mediated adiponectin expression system. We also examined the contribution of adiponectin deficiency to trinitrobenzene sulfonic acid (TNBS)-induced colitis. In vitro, we examined the effect of adiponectin on intestinal epithelial cells. After administration of 0.5% DSS for 15 days, APN-KO mice developed much more severe colitis compared with wild-type mice. The messenger RNA expression levels of chemokines were significantly higher in the colonic tissues of DSS-treated APN-KO mice compared with wild-type mice, accompanied by increased cellular infiltration, including macrophages. Adenovirus-mediated supplementation of adiponectin significantly attenuated the severity of colitis, but there were no differences in the severity of TNBS-induced colitis between the 2 groups. Adiponectin receptors were expressed in intestinal epithelial cells, and adiponectin inhibited lipopolysaccharide-induced interleukin-8 production in intestinal epithelial cells. Adiponectin is protective against DSS-induced murine colitis, probably due to the inhibition of chemokine production in intestinal epithelial cells and the following inflammatory responses, including infiltration of macrophages and release of proinflammatory cytokines.

Effect of dehydroepiandrosterone on lipopolysaccharide-induced interleukin-6 production in DH82 cultured canine macrophage cells

Objective This study examined the effect of dehydroepiandrosterone (DHEA) on lipopolysaccharide (LPS)-stimulated interleukin-6 (IL-6) production in the DH82 canine macrophage cell line. Study design Cultured DH82 cells were stimulated with varying concentrations of LPS with or without DHEA for various times. Supernatant IL-6 levels were measured by enzyme-linked immunosorbent assay, and cellular cytoplasmic IκBα protein expression measured by Western blot analysis. Results LPS dose-dependently stimulated IL-6 production ( p = 0.016). Cells stimulated with 20 μg LPS showed a time-dependent increase of IL-6 concentration up to 10 h post-treatment ( p = 0.007). Co-treatment of DH82 cells with 20 μg LPS and various concentrations of DHEA for 14 h showed that up to 10 μM DHEA dose-dependently decreased the IL-6 concentration ( p = 0.007). Also, addition of 20 μM DHEA to DH82 cells with 20 μg LPS time-dependently decreased the IL-6 concentration for up to 14 h post-treatment ( p = 0.018). Stimulation of cultured DH82 cells with 20μg LPS significantly decreased cellular cytoplasmic IκBα expression, beginning at 30 min post-treatment and persisting to at least 2 h post-treatment ( p = 0.012). However, co-treatment of cells with 20 μg LPS and 20 μM DHEA abrogated this effect until 2 h post-treatment. Conclusions DHEA decreased the IL-6 concentration in the supernatant of LPS-stimulated DH82 cells by inhibiting the sequestration of IκBα, which is necessary for the activation of nuclear factor-kappa B. These findings provide new insights into the immunomodulatory effects of DHEA.

Reduction of lipopolysaccharide-induced interleukin-6 production by the kappa opioid U50,488 in a mouse monocyte-like cell line

Several studies demonstrate that opioids modulate the immune response via opioid receptors expressed directly on the immune cells themselves. Recently, it has been suggested that the kappa opioid system has a modulatory role in various inflammatory diseases including rheumatoid arthritis. This modulation may occur via changes in cytokine secretion by monocyte-derived cells. To further study this opioid–immune relationship, we stimulated P388D1 cells, a mouse monocyte-like cell line, with lipopolysaccharide (LPS) in the presence or absence of the kappa opioid-selective ligand, U50,488. Pretreatment with U50,488 significantly reduced LPS-stimulated interleukin-6 (IL-6) production as measured by ELISA. This effect was mediated by the kappa opioid receptor, because nor-binaltorphimine (nor-BNI), a kappa-selective antagonist, blocked this inhibition. It is likely that this reduction of IL-6 protein by U50,488 treatment is attributed to decreases in IL-6 mRNA. RT-PCR experiments demonstrated that U50,488 treatment significantly reduced the LPS-mediated increase in IL-6 mRNA and that this effect was also blocked by nor-BNI. Understanding the mechanism behind the reduction of proinflammatory cytokine production by opioids may lead to the development of more effective therapeutics for inflammatory diseases.

Heat shock up‐regulates expression of Toll‐like receptor‐2 and Toll‐like receptor‐4 in human monocytes via p38 kinase signal pathway

Summary Heat stress can alert innate immunity by inducing stress proteins such as heat-shock proteins (HSPs). However, it remains unclear whether heat stress affects the activation of antigen-presenting cell (APC) in response to pathogen-associated molecule patterns (PAMPs) by directly regulating pathogen recognition receptors (PRRs). As an important kind of PRRs, Toll-like receptors (TLRs) play critical roles in the activation of immune system. In this study, we demonstrated that heat shock up-regulated the expression of HSP70 as well as TLR2 and TLR4 in monocytes. The induction of TLRs was prior to that of HSP70, which suggesting the up-regulation of TLR2 and TLR4 might be independent of the induction of HSP70. Heat shock activated p38 kinase, extracellular signal-related kinase (ERK) and nuclear factor-kappa B (NF-kappaB) signal pathways in monocytes. Pretreatment with specific inhibitor of p38 kinase, but not those of ERK and NF-kappaB, inhibited heat shock-induced up-regulation of TLR2 and TLR4. This indicates that p38 pathway takes part in heat shock-induced up-regulation of TLR2 and TLR4. Heat shock also increased lipoteichoic acid- or lipopolysaccharide-induced interleukin-6 production by monocytes. These results suggest that the p38 kinase-mediated up-regulation of TLR2 and TLR4 might be involved in the enhanced response to PAMP in human monocytes induced by heat shock.

Validation of a new highly standardised, lab-independent whole-blood leukocyte function assay for clinical trials (ILCS ®)

Physical stress induced in healthy volunteers by the Loughborough intermittent shuttle test (LIST) was used to validate a newly developed whole-blood cell culture system (Instant leukocyte culture system (ILCS ®)). Exercise induced immune modulation was investigated through measurement of cytokine levels after activating leukocytes in peripheral blood ex vivo using the physiologic stimulant lipopolysaccharide (LPS). LPS induced production of three different cytokines, interferon gamma (IFNγ), interleukin-6 (IL-6), and interleukin-10 (IL-10). IFNγ levels were significantly decreased ( P=0.02 and P=0.001) and IL-10 levels significantly increased ( P=0.04 and 0.03) after exercise. LPS induced IL-6 production was only marginally further increased by exercise. In conclusion, the ILCS ® system provided a reliable ex vivo method, showing common as well as subject specific features in the time course of the immune modulation caused by the LIST protocol. This system will be useful for studies of the elderly, where cytokine standardisation is notoriously difficult.