Hexavalent chromium induced ROS formation,Akt, NF-κB,and MAPK activation,and TNF-α and IL-1α production in keratinocytes

In certain cell types, it has been found that, hexavalent chromium could increase ROS formation, activate cell signaling and stimulate the release of cytokines. But, in keratinocytes, these effects have not yet fully been demonstrated. Our aim is to observe the above effects of hexavalent chromium on keratinocytes. By utilizing HaCaT cells and the skin of albino guinea pigs, we showed that hexavalent chromium could increase ROS formation, activate the Akt, NF-kB, and MAPK pathways as well as increase the production of cytokines, including TNF-α and IL-1α. The release of these cytokines from keratinocytes is considered to be a key participant in the pathogenesis of contact hypersensitivity. Among cement workers, chromium hypersensitivity is an important occupational skin disease issue. Therefore, the observations of our study help us better understand the role of hexavalent chromium on the development of chromium hypersensitivity, which might provide clues for clinicians in the development of chemopreventative agents for the prevention of chromium hypersensitivity among cement workers.     

Liuwei Dihuang-active fraction combination,LW-AFC,improved spatial learning and memory impairment induced by TNF-α in mice

OBJECTIVE Tumor necrosis factor-α(TNF-α) plays a vital role in cognitive dysfunction caused by stress.In our previous study, Liuwei Dihuang-active fraction combination(LW-AFC) could attenuate the effects of mental stress and non-psychotic stress in mice. The aim of this study is to investigate the effects of LW-AFC on cognitive dysfunction caused by TNF-α in mice. METHODS 40 male BALB/c mice were divided into 4 groups according to their body weight,including control, TNF-α model, LW-AFC treatment and Etanercept(TNF-α antagonist) treatment groups. LW-AFC(1.6 or 3.2 g·kg~(-1) per day) were orally administrated for 7 consecutive days before TNF-α administration. Etanercept was injected subcutaneously at 30 mg·kg~(-1) the day before TNF-α administration. One hour before the behavioral test, TNF-αwere injected intraperitoneally at 0.2 mg·kg~(-1) to mice. RESULTS Compared with control group, the time of mice stayed in the target quadrant and the number of mice crossing the plate significantly decreased after TNF-α injection, suggested that the spatial learning and memory ability of the mice were impaired. LW-AFC administration could increase the time of mice stayed in the target quadrant and the number of mice crossing the plate significantly at 1.6 g·kg~(-1), indicated that LW-AFC could improve spatial learning and memory in TNF-α treated mice. CONCLUSION LW-AFC can improve spatial learning and memory impairment induced by TNF-α in mice, the further mechanism still need to be clarified.     

Toll-like receptor 2/MyD88 signaling mediates zymosan-induced joint hypernociception in mice: participation of TNF-α, IL-1β and CXCL1/KC

Arthritic pain is a serious health problem that affects a large number of patients. Toll-like receptors (TLRs) activation within the joints has been implicated in pathophysiology of arthritis. However, their role in the genesis of arthritic pain needs to be demonstrated. In the present study, it was addressed the participation of TLR2 and TLR4 and their adaptor molecule MyD88 in the genesis of joint hypernociception (a decrease in the nociceptive threshold) during zymosan-induced arthritis. Zymosan injected in the tibio-tarsal joint induced mechanical hypernociception in C57BL/6 wild type mice that was reduced in TLR2 and MyD88 null mice. On the other hand, zymosan-induced hypernociception was similar in C3H/HePas and C3H/HeJ mice (TLR4 mutant mice). Zymosan-induced joint hypernociception was also reduced in TNFR1 null mice and in mice treated with IL-1 receptor antagonist or with an antagonist of CXCR1/2. Moreover, the joint production of TNF-α, IL-1β and CXCL1/KC by zymosan was dependent on TLR2/MyD88 signaling. Investigating the mechanisms by which TNF-α, IL-1β and CXCL1/KC mediate joint hypernociception, joint administration of these cytokines produced mechanical hypernociception, and they act in an interdependent manner. In last instance, their hypernociceptive effects were dependent on the production of hypernociceptive mediators, prostaglandins and sympathetic amines. These results indicate that in zymosan-induced experimental arthritis, TLR2/MyD88 is involved in the cascade of events of joint hypernociception through a mechanism dependent on cytokines and chemokines production. Thus, TLR2/MyD88 signaling might be a target for the development of novel drugs to control pain in arthritis.     

Chondroprotective and anti-inflammatory role of melanocortin peptides in TNF-α activated human C-20/A4 chondrocytes

BACKGROUND AND PURPOSE

Melanocortin MC₁ and MC₃ receptors, mediate the anti-inflammatory effects of melanocortin peptides. Targeting these receptors could therefore lead to development of novel anti-inflammatory therapeutic agents. We investigated the expression of MC₁ and MC₃ receptors on chondrocytes and the role of α-melanocyte-stimulating hormone (α-MSH) and the selective MC₃ receptor agonist, [DTRP⁸]-γ-MSH, in modulating production of inflammatory cytokines, tissue-destructive proteins and induction of apoptotic pathway(s) in the human chondrocytic C-20/A4 cells.

EXPERIMENTAL APPROACH

Effects of α-MSH, [DTRP⁸]-γ-MSH alone or in the presence of the MC_3/4 receptor antagonist, SHU9119, on TNF-α induced release of pro-inflammatory cytokines, MMPs, apoptotic pathway(s) and cell death in C-20/A4 chondrocytes were investigated, along with their effect on the release of the anti-inflammatory cytokine IL-10.

KEY RESULTS

C-20/A4 chondrocytes expressed functionally active MC_1,3 receptors. α-MSH and [DTRP⁸]-γ-MSH treatment, for 30 min before TNF-α stimulation, provided a time-and-bell-shaped concentration-dependent decrease in pro-inflammatory cytokines (IL-1β, IL-6 and IL-8) release and increased release of the chondroprotective and anti-inflammatory cytokine, IL-10, whilst decreasing expression of MMP1, MMP3, MMP13 genes.α-MSH and [DTRP⁸]-γ-MSH treatment also inhibited TNF-α-induced caspase-3/7 activation and chondrocyte death. The effects of [DTRP⁸]-γ-MSH, but not α-MSH, were abolished by the MC_3/4 receptor antagonist, SHU9119.

CONCLUSION AND IMPLICATIONS

Activation of MC₁/MC₃ receptors in C-20/A4 chondrocytes down-regulated production of pro-inflammatory cytokines and cartilage-destroying proteinases, inhibited initiation of apoptotic pathways and promoted release of chondroprotective and anti-inflammatory cytokines. Developing small molecule agonists to MC₁/MC₃ receptors could be a viable approach for developing chondroprotective and anti-inflammatory therapies in rheumatoid and osteoarthritis.     

The role of α1 and α5 subunit-containing GABAA receptors in motor impairment induced by benzodiazepines in rats

Benzodiazepines negatively affect motor coordination and balance and produce myorelaxation. The aim of the present study was to examine the extent to which populations of γ-aminobutyric acid A (GABAA) receptors containing α1 and α5 subunits contribute to these motor-impairing effects in rats. We used the nonselective agonist diazepam and the α1-selective agonist zolpidem, as well as nonselective, α1-subunit and α5-subunit-selective antagonists flumazenil, βCCt, and XLi093, respectively. Ataxia and muscle relaxation were assessed by rotarod and grip strength tests performed 20 min after intraperitoneal treatment. Diazepam (2 mg/kg) induced significant ataxia and muscle relaxation, which were completely prevented by pretreatment with flumazenil (10 mg/kg) and βCCt (20 mg/kg). XLi093 antagonized the myorelaxant, but not the ataxic actions of diazepam. All three doses of zolpidem (1, 2, and 5 mg/kg) produced ataxia, but only the highest dose (5 mg/kg) significantly decreased the grip strength. These effects of zolpidem were reversed by βCCt at doses of 5 and 10 mg/kg, respectively. The present study demonstrates that α1 GABAA receptors mediate ataxia and indirectly contribute to myorelaxation in rats, whereas α5 GABAA receptors contribute significantly, although not dominantly, to muscle relaxation but not ataxia.     

Pyrroloquinoline quinone delays inflammaging induced by TNF-α through the p16/p21 and Jagged1 signalling pathways

Previous studies on the longevity effect of pyrroloquinoline quinine (PQQ) on nematode worms have revealed that PQQ can enhance the antioxidant capacity of nematode worms, thus extending the lifespan of the worms. The induction and development of cellular senescence are closely connected with inflammatory reactions. The aim of this study was to determine the effect of PQQ and ageing factors on senescent cells. To this end, we cultivated human embryonic lung fibroblasts in nutrient solution with or without tumour necrosis factor-alpha (TNF-α) to establish an inflammaging model in vitro. The cells were preincubated with or without PQQ to determine if PQQ had any anti-inflammaging effect. More senescent cells were detected with the addition of TNF-α than without (P < .01). The ratio of senescent cells to non-senescent cells in the TNF-α group was greater than that in the control group (P < .01). When cells were preincubated with PQQ prior to TNF-α treatment, there were fewer senescent cells than those in the control group, which was not pretreated with PQQ (P < .05). The same tendency was noted with regard to p21, p16, and Jagged1. In summary, we used TNF-α, a well-known pro-inflammatory cytokine associated with inflammaging, to establish an in vitro inflammaging model and provided evidence that PQQ delays TNF-α –induced cellular senescence and has anti-inflammaging properties.     

Hyperactivity induced by dexamphetamine/chlordiazepoxide mixtures in rats and its attenuation by lithium pretreatment: a role for dopamine?

Dexamphetamine (DEX) and chlordiazepoxide (CDZP) given together as mixtures have previously been shown to induce a characteristic compulsive form of locomotor hyperactivity in rats placed in unfamiliar environments, which was much greater than activity obtained with any dose of either drug given separately; acute pretreatment with lithium counteracted mixture-induced hyperactivity. The role of dopamine in these effects was investigated by measuring concurrently the levels of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum. DEX (0.02-2 mg kg^-1) increased horizontal (entries) and vertical (rears) activity, and increased DA and decreased DOPAC and HVA in the striatum. Chlordiazepoxide (CDZP) (12.5 or 20 mg kg^-1) increased horizontal activity but did not affect vertical activity or DA or its metabolites. Lithium by itself in acute (2 meq kg^-1, 24 and 4 h before test) or extended (2 meq kg^-1 daily for 9 days) dosage had little effect on horizontal or vertical activity or levels of DA or DOPAC. Given together, DEX and CDZP (1.18 mg kg^-1 + 12.5 mg kg^-1), as expected, increased entries much more than did either drug given separately, but rears and levels of DA and metabolites remained similar to those with DEX given alone. Acute lithium pretreatment counteracted the mixture-induced increase in entries. Neither acute nor extended lithium pretreatment significantly altered DEX-induced changes in activity or levels of DA or DOPAC. The results suggest that an action on striatal DA neurones is responsible neither for the increases in entries seen after CDZP and CDZP/DEX mixtures (compared with DEX alone), nor for the attenuating effect of acute lithium on the mixture-induced increases. The changes in vertical activity (rearing) observed with DEX alone may, however, reflect an action on DA neurones. Animal models of mania are discussed.     

Rutin attenuates cisplatin induced renal inflammation and apoptosis by reducing NFκB, TNF-α and caspase-3 expression in wistar rats

Cisplatin is an effective chemotherapeutic agent that displays dose-limiting nephrotoxicity. In the present study the wistar rats were subjected to concurrent prophylactic oral treatment of rutin (75 and 150 mg/kg b.wt.) against the nephrotoxicity induced by intraperitoneal administration of cisplatin (7 mg/kg b.wt.). Efficacy of rutin against the nephrotoxicity was evaluated in terms of biochemical estimation of antioxidant enzyme activities, histopathological changes and expression levels of molecular markers of inflammation and apoptosis. Rutin pretreatment prevented deteriorative effects induced by cisplatin through a protective mechanism that involved reduction of increased oxidative stress as well as caspase-3, TNF-α and NFκB protein expression levels. We found that the beneficial effect of rutin pretreatment is mediated partially by its inhibitory effect on NFκB and TNF-α pathway mediated inflammation, caspase-3 mediated-tubular cell apoptosis, as well as by restoration of histopathological changes against cisplatin administration.     

Synergistic induction of CCL5, CXCL9 and CXCL10 by IFN-γ and NLRs ligands on human fibroblast-like synoviocytes—A potential immunopathological mechanism for joint inflammation in rheumatoid arthritis

Interferon-γ (IFN-γ) is traditionally regarded as a proinflammatory cytokine by virtue of its strong macrophage activating potential and its association with Th1 driven immune responses. NOD1 and NOD2 are cytoplasmic receptors that can initiate the initial immune response by sensing bacterial components or danger signals. In this study, we investigated the immunopathological roles of IFN-γ and NOD1, 2 ligands iE-DAP/MDP on the activation of fibroblast-like synoviocytes (FLS) in RA. FLS constitutively express functional NOD1 and NOD2, and the gene and protein expression of NOD1 and NOD2 could be enhanced by the treatment with IFN-γ. The synergistic effect was observed in the combined treatment of IFN-γ and NOD1 ligand iE-DAP or NOD2 ligand MDP on the release of CCL5, CXCL9 and CXCL10 from FLS, and its effect was in a dose-dependent manner. The co-stimulation which IFN-γ combined with iE-DAP/MDP could abolish the inhibition of CXCL8 level by IFN-γ alone. Further investigations showed that synergistic effects on the production of CCL5, CXCL9 and CXCL10 in FLS stimulated by IFN-γ and iE-DAP/MDP were differentially regulated by intracellular activation of NF-κB, p38MAPK and ERK pathways. In conclusion, our data confirmed the inflammatory effect of IFN-γ and iE-DAP/MDP on human FLS for the first time and therefore provided a new insight into the IFN-γ combined with NOD1 or NOD2 activated immunopathological mechanisms mediated by distinct intracellular signal transduction in joint inflammation of RA.     

Proteomic analysis of trichloroethylene-induced alterations in expression, distribution, and interactions of SET/TAF-Iα and two SET/TAF-Iα-binding proteins, eEF1A1 and eEF1A2, in hepatic L-02 cells

Emerging evidence indicates that trichloroethylene (TCE) exposure causes severe hepatotoxicity. However, the mechanisms of TCE hepatotoxicity remain unclear. Recently, we reported that TCE exposure up-regulated the expression of the oncoprotein SET/TAF-Iα and SET knockdown attenuated TCE-induced cytotoxicity in hepatic L-02 cells. To decipher the function of SET/TAF-Iα and its contributions to TCE-induced hepatotoxicity, we employed a proteomic analysis of SET/TAF-Iα with tandem affinity purification to identify SET/TAF-Iα-binding proteins. We identified 42 novel Gene Ontology co-annotated SET/TAF-Iα-binding proteins. The identifications of two of these proteins (eEF1A1, elongation factor 1-alpha 1; eEF1A2, elongation factor 1-alpha 2) were confirmed by Western blot analysis and co-immunoprecipitation (Co-IP). Furthermore, we analyzed the effects of TCE on the expression, distribution and interactions of eEF1A1, eEF1A2 and SET in L-02 cells. Western blot analysis reveals a significant up-regulation of eEF1A1, eEF1A2 and two isoforms of SET, and immunocytochemical analysis reveals that eEF1A1 and SET is redistributed by TCE. SET is redistributed from the nucleus to the cytoplasm, while eFE1A1 is translocated from the cytoplasm to the nucleus. Moreover, we find by Co-IP that TCE exposure significantly increases the interaction of SET with eEF1A2. Our data not only provide insights into the physiological functions of SET/TAF-Iα and complement the SET interaction networks, but also demonstrate that TCE exposure induces alterations in the expression, distribution and interactions of SET and its binding partners. These alterations may constitute the mechanisms of TCE cytotoxicity.     

The role of Act1, a NF-κB-activating protein,in IL-6 and IL-8 levels induced by IL-17 stimulation in SW982 cells

Abstract

Context: Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation in the synovial membrane of affected joints. It has been shown that several kinds of cytokine were increased in synovial fluid, while the underlying mechanism remains poorly understood.

Objectives: NF-κB activator 1 (Act1) is a recently identified protein binding to the IκB kinase complex. Our study aimed to investigate the expression of Act1 induced by cytokine IL-17 stimulation in SW982 cells.

Materials and methods: The human synovial sarcoma cell line SW982 and primary cultured RA fibroblast-like synovial cells were used. RT-PCR and Western blot assays were selected to investigate the genetic and protein expression of Act1. Additionally, four independent Act1 small interfering RNA (siRNA) oligonucleotides were designed and obtained according to the GenBank cDNA, the sequence of Act1 (Traf3ip2). Finally, enzyme-linked immunosorbent assay (ELISA) double antibody sandwich was used to assay supernatant IL-6 and IL-8 concentrations.

Results: The Act1 mRNA expression level increased significantly after stimulation with IL-17 (5–100?ng/ml) in SW982 cells. Additionally, the level of Act1 mRNA expression correlated positively with the concentration of IL-17 (p?<?0.01). IL-17 induced IL-6 and IL-8 in SW982 cells was in a concentration- and time-dependent way. Furthermore, ELISA assay revealed that IL-17 (20?ng/ml) significantly increased IL-6 (1927.4?±?288.77 versus 786.5?±?172.42?ng/ml, p?<?0.01) and IL-8 levels (984.8?±?95.09?ng/ml versus 307.1?±?90.83?ng/ml, p?<?0.01) compared with control group after stimulation for 24?h. However, transfection of Traf3ip2 siRNA markedly decreased IL-6 (995.9?±?115.30?ng/ml versus 1816.1?±?273.27?ng/ml, p?<?0.01) and IL-8 levels (575.6?±?65.96?ng/ml versus 929.4?±?124.39?ng/ml, p?<?0.01) compared to transfection negative control. These findings suggested that IL-6 and IL-8 level induced by IL-17 in SW982 cells could be reversed by down-regulation of Act1 expression level with Traf3ip2 siRNA.

Conclusion: Our results suggested that Act1 might play a key role in the pathophysiology and the treatment of RA.     

Isolation,purification, LC–MS/MS characterization and reactive oxygen species induced by fumonisin B1 in VERO cells

Fumonisins are mycotoxins produced by Fusarium verticillioides that commonly contaminate maize and maize products. The present work shows the results of a comparative study of three different fermentation’s techniques (solid and liquid medium of corn and a solid agarized medium) for the production of fumonisins B₁, B₂ and B₃ with strains of F. verticillioides. The solid medium of corn was the most effective in the production of fumonisins, being Fumonisin B₁ the one produced with higher concentration, so the extract obtained by solid fermentation process was used for FB₁ purification. Fumonisins characterization and quantification were performed with reversed-phase high-performance liquid chromatography with electrospray ionization triple quadrupole tandem mass spectrometry. The role of production of reactive oxygen species (ROS) in Fumonisin B₁ mediated toxicology has not been fully addresses in studies exploring FB₁ toxicity. It is evaluated the level of ROS production in kidney cell line (VERO) exposed to 1, 5 and 10 μM of FB₁ for 0.5–100 min. The ROS level was detected using a fluorescence probe, 2′,7′-dichlorofluorescein diacetate (DCFH-DA), which could be converted to highly fluorescent dichlorofluorescein (DCF) with the presence of intracellular ROS. Significant increase of ROS products was observed in VERO cells at 10 μM dose. These results indicate that ROS production by FB₁ on renal cells is a mechanism of fumonisin mediated toxicity.     

Potent inhibition of human sulfotransferase 1A1 by 17α-ethinylestradiol: role of 3'-phosphoadenosine 5'-phosphosulfate binding and structural rearrangements in regulating inhibition and activity

Sulfotransferase (SULT) 1A1 is the major drug/xenobiotic-conjugating SULT isoform in human liver because of its broad substrate reactivity and high expression level. SULT1A1 sulfates estrogens with low micromolar K(m) values consistent with its affinity for sulfation of many small phenolic compounds. Binding studies showed the unexpected ability of 17α-ethinylestradiol (EE2) to bind and inhibit SULT1A1 activity toward p-nitrophenol and β-naphthol at low nanomolar concentrations, whereas EE2 was not sulfated until significantly higher concentrations were reached. EE2 had a K(i) of 10 nM for inhibiting p-nitrophenol and β-naphthol sulfation and inhibited 17β-estradiol (E2) sulfation in intact human MCF-7 breast cancer cells with a K(i) of 19 nM. In contrast, the K(m) for EE2 sulfation by SULT1A1 was 700 nM. The K(d) for EE2 binding of pure SULT1A1 was 0.5 ± 0.15 μM; however, the K(d) for EE2 binding to the SULT1A1-PAP complex was >100-fold lower (4.3 ± 1.7 nM). The K(d) for E2 binding to SULT1A1 changed from 2.3 ± 0.9 to 1.2 ± 0.56 μM in the presence of PAP. Docking studies with E2 indicate that E2 binds in a competent orientation in the resolved structure of SULT1A1 in the both presence and absence of 3'-phosphoadenosine 5'-phosphosulfate (PAPS). However, EE2 binds in a catalytically competent orientation in the absence of PAPS but in a noncompetent orientation via formation of a charge interaction with Tyr108 if PAPS is bound first. In conclusion, EE2 is a potent inhibitor, but not a substrate, of SULT1A1 at low nanomolar concentrations, indicating the possibility of drug-drug interactions during contraceptive therapy.     

CTB glycoprotein (75 kDa) inhibits IgE releasing,TNF-α and IL-6 expressed by bisphenol A in vivo and in vitro

Cudrania tricuspidata Bureau (CTB) has been used to treat allergies and inflammatory disease as folk medicine in Korea. The objective of this study is to determine whether a glycoprotein isolated from CTB (75 kDa) has a preventive potential of allergic inflammation caused by bisphenol A (BPA) in BALB/c mice and RBL-2H3 cells. Production of immunoglobulin (Ig) E and releasing of β-hexosaminidase and histamine at treatment of CTB glycoprotein (5–10 mg/kg, BW) were evaluated in mice serum. Activation of extracellular signal-regulated kinases (ERK) and p38 mitogen-activated protein kinase (MAPK), activator protein (AP)-1, expressions of pro-inflammatory cytokines, nitric oxide (NO) production and cyclooxygenase (COX)-2 were assessed in RBL-2H3 cells. In the results, CTB glycoprotein (10 mg/kg, BW) inhibited the production of IgE and releasing of β-hexosaminidase and histamine. Also, the CTB glycoprotein (100 μg/ml) blocked phosphorylation of ERK1/2 and p38 MAPK, and the activation of AP-1, while it inhibited the NO production, activities of COX-2, tumor necrosis factor (TNF)-α, and interleukin (IL)-6, but not IL-1β. Taken together, the results of this study indicated that the CTB glycoprotein modulates the expression of allergic inflammation-related factors via the suppression of MAPK/AP-1 activation.     

Naringenin ameliorates inflammation and cell proliferation in benzo(a)pyrene induced pulmonary carcinogenesis by modulating CYP1A1, NFκB and PCNA expression

Lung cancer is the major cause of cancer-related mortality and is a growing economic burden worldwide. Chemoprevention has emerged as a very effective preventive measure against carcinogenesis and several bioactive compounds in diet have shown their cancer curative potential on lung cancer. Naringenin (NRG), a predominant flavanone found in citrus fruits has been reported to possess anti-oxidative, anti-inflammatory and anti-proliferative activity in a wide variety of cancer. The aim of the present study is to divulge the chemopreventive nature of NRG against benzo(a)pyrene (B[a]P) induced lung carcinogenesis in Swiss albino mice. Administration of B[a]P (50 mg/kg, p.o.) to mice resulted in increased lipid peroxidation (LPO), proinflammatory cytokines (TNF-α, IL-6 and IL-1β) with subsequent decrease in activities of tissue enzymic antioxidants (SOD, CAT, GPx, GR, GST) and non-enzymic antioxidants (GSH and Vit-C). Treatment with NRG (50 mg/kg body weight) significantly counteracted all these alterations thereby showing potent anti-cancer effect in lung cancer. Moreover, assessment of protein expression by immunoblotting and mRNA expression by RT-PCR revealed that NRG treatment effectively negates B[a]P-induced upregulated expression of CYP1A1, PCNA and NF-κB. Further, the antiproliferative effect of NRG was confirmed by histopathological analysis and PCNA immunostaining in B[a]P induced mice which showed increased PCNA expression that was restored upon NRG administration. Overall, these findings substantiate the chemopreventive potential of NRG against chemically induced lung cancer in mice.     

Expression of TNF-α and IL-6 in HMC-1 cells treated with bisphenol A is attenuated by plant-originating glycoprotein (75 kDa) by blocking p38 MAPK

Bisphenol A (BPA) is known as an estrogen-mimic environmental hormone which has the ability to indirectly stimulate the production of allergic inflammation-related cytokines. Cudrania tricuspidata Bureau (CTB) has been used in Korean folk medicine for a long time. In order to determine the inhibitory effect of a glycoprotein (CTB glycoprotein, 75 kDa) isolated from CTB fruits on the activities of allergic inflammation-related cytokines (TNF-α and IL-6) caused by BPA, we evaluated the activities of protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor (NF)-κB, and inflammation-related cytokine (TNF-α and IL-6) in the BPA-induced HMC-1 cells using immunoblot analysis and RT-PCR. The results obtained from this study revealed that CTB glycoprotein (100 μg/ml) inhibits the translocation of PKC from cytosol to the membrane, the phosphorylation of p38 MAPK, the activation of NF-κB, and the expression levels of TNF-α and IL-6. Taken together, the results in this study suggest that CTB glycoprotein inhibits the expression of allergic inflammation-related cytokines (TNF-α and IL-6) by blocking NF-κB and p38 kinase in BPA-induced HMC-1 cells.     

Selective role for tumor necrosis factor-α, but not interleukin-1 or Kupffer cells, in down-regulation of CYP3A11 and CYP3A25 in livers of mice infected with a noninvasive intestinal pathogen

Hepatic cytochrome P450 (P450) gene and protein expression are modulated during inflammation and infection. Oral infection of C57BL/6 mice with Citrobacter rodentium produces mild clinical symptoms while selectively regulating hepatic P450 expression and elevating levels of proinflammatory cytokines. Here, we explored the role of cytokines in the regulation of hepatic P450 expression by orally infecting tumor necrosis factor-α (TNFα) receptor 1 null mice (TNFR1−/−), interleukin-1 (IL1) receptor null mice (IL1R1−/−), and Kupffer cell depleted mice with C. rodentium. CYP4A mRNA and protein levels and flavin monooxygenase (FMO)3 mRNA expression levels were down-regulated, while CYP2D9 and CYP4F18 mRNAs remained elevated during infection in wild-type, receptor knockout, and Kupffer cell depleted mice. CYPs 3A11 and 3A25 mRNA levels were down-regulated during infection in wild-type mice but not in TNFR1−/− mice. Consistent with this observation, CYPs 3A11 and 3A25 were potently down-regulated in mouse hepatocytes treated with TNFα. Oral infection of IL1R1−/− mice and studies with mouse hepatocytes indicated that IL1 does not directly regulate CYP3A11 or CYP3A25 expression. Uninfected mice injected with clodronate liposomes had a significantly reduced number of Kupffer cells in their livers. Infection increased the Kupffer cell count, which was attenuated by clodronate treatment. The P450 mRNA and cytokine levels in infected Kupffer cell depleted mice were comparable to those in infected mice receiving no clodronate. The results indicate that TNFα is involved in the regulation of CYPs 3A11 and 3A25, but IL1β and Kupffer cells may not be relevant to hepatic P450 regulation in oral C. rodentium infection.