Ethanol induces the production of cytokines via the Ca2+, MAP kinase, HIF-1α, and NF-κB pathway

Glucocorticoid Alleviates Mechanical Stress-Induced Airway Inflammation and Remodeling in COPD via Transient Receptor Potential Canonical 1 Channel

Background

Increased airway resistance and hyperinflation in chronic obstructive pulmonary disease (COPD) are associated with increased mechanical stress that modulate many essential pathophysiological functions including airway remodeling and inflammation. Our present study aimed to investigate the role of transient receptor potential canonical 1 (TRPC1), a mechanosensitive cation channel in airway remodeling and inflammation in COPD and the effect of glucocorticoid on this process.

Methods

In patients, we investigated the effect of pathological high mechanical stress on the expression of airway remodeling-related cytokines transforming growth factor β1 (TGF-β1), matrix metalloproteinase-9 (MMP9) and the count of inflammatory cells in endotracheal aspirates (ETAs) by means of different levels of peak inspiratory pressure (PIP) under mechanical ventilation, and analyzed their correlation with TRPC1. Based on whether patients regularly used inhaled corticosteroid (ICS), COPD patients were further divided into ICS group (n = 12) and non-ICS group (n=15). The ICS effect on the expression of TRPC1 was detected by Western blot. In vitro, we imitated the mechanical stress using cyclic stretch and examined the levels of TGF-β1 and MMP-9. The role of TRPC1 was further explored by siRNA transfection and dexamethasone administration.

Results

Our results revealed that the TRPC1 level and the inflammatory cells counts were significantly higher in COPD group. After mechanical ventilation, the expression of TGF-β1 and MMP-9 in all COPD subgroups was significantly increased, while in the control group, only high PIP subgroup increased. Meanwhile, TRPC1 expression was positively correlated with the counts of inflammatory cells and the levels of TGF-β1 and MMP-9. In vitro, mechanical stretch significantly increased TGF-β1 and MMP-9 levels and such increase was greatly attenuated by TRPC1 siRNA transfection and dexamethasone administration.

Conclusion

Our results suggest that the increased TRPC1 may play a role in the airway inflammation and airway remodeling in COPD under high airway pressure. Glucocorticoid could in some degree alleviate airway remodeling via inhibition of TRPC1.

Prostaglandin F2α requires activation of calcium-dependent signalling to trigger inflammation in human myometrium

Introduction

Preterm birth is one of the major causes of neonatal morbidity and mortality across the world. Both term and preterm labour are preceded by inflammatory activation in uterine tissues. This includes increased leukocyte infiltration, and subsequent increase in chemokine and cytokine levels, activation of pro-inflammatory transcription factors as NF-κB and increased prostaglandin synthesis. Prostaglandin F2α (PGF2α) is one of the myometrial activators and stimulators.

Methods

Here we investigated the role of PGF2α in pro-inflammatory signalling pathways in human myometrial cells isolated from term non-labouring uterine tissue. Primary myometrial cells were treated with G protein inhibitors, calcium chelators and/or PGF2α. Nuclear extracts were analysed by TranSignal cAMP/Calcium Protein/DNA Array. Whole cell protein lysates were analysed by Western blotting. mRNA levels of target genes were analysed by RT-PCR.

Results

The results show that PGF2α increases inflammation in myometrial cells through increased activation of NF-κB and MAP kinases and increased expression of COX-2. PGF2α was found to activate several calcium/cAMP-dependent transcription factors, such as CREB and C/EBP-β. mRNA levels of NF-κB-regulated cytokines and chemokines were also elevated with PGF2α stimulation. We have shown that the increase in PGF2α-mediated COX-2 expression in myometrial cells requires coupling of the FP receptor to both Gαq and Gαi proteins. Additionally, PGF2α-induced calcium response was also mediated through Gαq and Gαi coupling.

Discussion

In summary, our findings suggest that PGF2α-induced inflammation in myometrial cells involves activation of several transcription factors - NF-κB, MAP kinases, CREB and C/EBP-β. Our results indicate that the FP receptor signals via Gαq and Gαi coupling in myometrium. This work provides insight into PGF2α pro-inflammatory signalling in term myometrium prior to the onset of labour and suggests that PGF2α signalling pathways could be a potential target for management of preterm labour.

Chemogenetic manipulation of astrocytic signaling in the basolateral amygdala reduces binge-like alcohol consumption in male mice

Binge drinking is a common occurrence in the United States, but a high concentration of alcohol in the blood has been shown to have reinforcing and reciprocal effects on the neuroimmune system in both dependent and non-dependent scenarios. The first part of this study examined alcohol's effects on the astrocytic response in the central amygdala and basolateral amygdala (BLA) in a non-dependent model. C57BL/6J mice were given access to either ethanol, water, or sucrose during a "drinking in the dark" paradigm, and astrocyte number and astrogliosis were measured using immunohistochemistry. Results indicate that non-dependent consumption increased glial fibrillary acidic protein (GFAP) density but not the number of GFAP+ cells, suggesting that non-dependent ethanol is sufficient to elicit astrocyte activation. The second part of this study examined how astrocytes impacted behaviors and the neurochemistry related to alcohol using the chemogenetic tool, DREADDs (designer receptors exclusively activated by designer drugs). Transgenic GFAP-hM3Dq mice were administered clozapine N-oxide both peripherally, affecting the entire central nervous system (CNS), or directly into the BLA. In both instances, GFAP-Gq-signaling activation significantly reduced ethanol consumption and correlating blood ethanol concentrations. However, GFAP-Gq-DREADD activation throughout the CNS had more broad effects resulting in decreased locomotor activity and sucrose consumption. More targeted GFAP-Gq-signaling activation in the BLA only impacted ethanol consumption. Finally, a glutamate assay revealed that after GFAP-Gq-signaling activation glutamate concentrations in the amygdala were partially normalized to control levels. Altogether, these studies support the theory that astrocytes represent a viable target for alcohol use disorder therapies.

Inhibitory effects of bee venom on mast cell-mediated allergic inflammatory responses

Although bee venom (BV) is a toxin that causes bee stings to be painful, it has been widely used clinically for the treatment of certain immune‑associated diseases. BV has been used traditionally for the treatment of chronic inflammatory diseases. In this regard, the present study analyzed the effect of BV on the regulation of inflammatory mediator production by mast cells and their allergic inflammatory responses in an animal model. HMC‑1 cells were treated with BV prior to stimulation with phorbol‑12‑myristate 13‑acetate plus calcium ionophore A23187 (PMACI). The production of allergy‑associated pro‑inflammatory mediators was examined, and the underlying mechanisms were investigated. Furthermore, to investigate whether BV exhibits anti‑inflammatory effects associated with anti‑allergic effects in vivo, a compound 48/80‑induced anaphylaxis model was used. BV inhibited histamine release, mRNA expression and production of cytokines in the PMACI‑stimulated HMC‑1 cells. Furthermore, the inhibitory effects of BV on mitogen‑activated protein kinase (MAPK), MAPK kinase, signal transducer and activator of transcription 3 (STAT3) and Akt were demonstrated. The present study also investigated the ability of BV to inhibit compound 48/80‑induced systemic anaphylaxis in vivo. BV protected the mice against compound 48/80‑induced anaphylactic‑associated mortality. Furthermore, BV suppressed the mRNA expression levels of pro‑inflammatory cytokines, and suppressed the activation of MAPK and STAT3 in this model. These results provide novel insights into the possible role of BV as a modulator for mast cell‑mediated allergic inflammatory disorders.

Light/Dark Shifting Promotes Alcohol-Induced Colon Carcinogenesis: Possible Role of Intestinal Inflammatory Milieu and Microbiota

Background: Colorectal cancer (CRC) is associated with the modern lifestyle. Chronic alcohol consumption—a frequent habit of majority of modern societies—increases the risk of CRC. Our group showed that chronic alcohol consumption increases polyposis in a mouse mode of CRC. Here we assess the effect of circadian disruption—another modern life style habit—in promoting alcohol-associated CRC. Method: TS4Cre × adenomatous polyposis coli (APC)^lox468 mice underwent (a) an alcohol-containing diet while maintained on a normal 12 h light:12 h dark cycle; or (b) an alcohol-containing diet in conjunction with circadian disruption by once-weekly 12 h phase reversals of the light:dark (LD) cycle. Mice were sacrificed after eight weeks of full alcohol and/or LD shift to collect intestine samples. Tumor number, size, and histologic grades were compared between animal groups. Mast cell protease 2 (MCP2) and 6 (MCP6) histology score were analyzed and compared. Stool collected at baseline and after four weeks of experimental manipulations was used for microbiota analysis. Results: The combination of alcohol and LD shifting accelerated intestinal polyposis, with a significant increase in polyp size, and caused advanced neoplasia. Consistent with a pathogenic role of stromal tryptase-positive mast cells in colon carcinogenesis, the ratio of mMCP6 (stromal)/mMCP2 (intraepithelial) mast cells increased upon LD shifting. Baseline microbiota was similar between groups, and experimental manipulations resulted in a significant difference in the microbiota composition between groups. Conclusions: Circadian disruption by Light:dark shifting exacerbates alcohol-induced polyposis and CRC. Effect of circadian disruption could, at least partly, be mediated by promoting a pro-tumorigenic inflammatory milieu via changes in microbiota.

A pre-injury high ethanol intake in rats promotes brain edema following traumatic brain injury

Drinking is a risk factor for traumatic brain injury (TBI), and ethanol can aggravate the outcome by promoting brain edema. The mechanism involved is not fully understood. It has been confirmed that aquaporin-4 (AQP4) and vascular endothelial growth factor (VEGF) play pivotal roles in cytotoxic/vasogenic brain edema individually, and both of these proteins are downstream regulatory factors of hypoxia-inducible factor-1α (HIF-1α). In this study, we used a fluid percussion injury (FPI) model in rats to determine the effects of acute ethanol intake on the expression levels of HIF-1α, AQP4, and VEGF prior to FPI. The animals were sacrificed 1, 2, 3, and 4 days post-injury. We found that the expression levels of HIF-1α and AQP4 were significantly upregulated in the ethanol-pretreated groups, whereas the VEGF expression level was not. In addition, there was a positive correlation between HIF-1α and AQP4. The results of this study indicate that cytotoxic brain edema may play an important role in the early stage of FPI in ethanol-pre-treated animals and that HIF-1α and AQP4 might be involved.

Ethanol-induced mast cell-mediated inflammation leads to increased susceptibility of intestinal tumorigenesis in the APC Δ468 min mouse model of colon cancer

BACKGROUND

Chronic and frequent alcohol (ethanol [EtOH]) intake has been associated with an increased incidence of several types of cancers including breast, mouth, throat, esophageal, stomach, and colorectal (CRC). The underlying mechanism of this deleterious carcinogenic effect of alcohol has not been clearly established but inflammation may be 1 unifying feature of these cancers. We have recently shown that intestinal mast cells play a central role in intestinal carcinogenesis. In this study, we tested our hypothesis that mast cell-mediated inflammation is 1 underlying mechanism by which chronic alcohol promotes intestinal tumorigenesis.

METHODS

APC(Δ468) mice were fed either an alcohol-containing Nanji liquid diet or isocaloric dextrose-containing Nanji diet for 10 weeks and then sacrificed to collect small and large intestine samples. Assessments of tumor number and size as well as mast cell number and mast cell activity and histology score for invasion were compared between Control (dextrose-fed) and alcohol-fed APC(∆468) mice. The effect of alcohol on mast cell-mediated tumor migration was also assessed using an in vitro migration assay.

RESULTS

Alcohol feeding increased both polyp number and size within both the small and the large intestines of APC(∆468) mice. Only alcohol-fed mice showed evidence of tumor invasion. Chronic alcohol feeding also resulted in an increased mast cell number and activity in tumor stroma and invading borders. In vitro migration assay showed that alcohol significantly increases mast cell-mediated tumor migration in vitro.

CONCLUSIONS

Our data show that chronic alcohol intake promotes: (i) intestinal tumorigenesis and tumor invasion in genetically susceptible mice; (ii) increases in polyp-associated mast cells; and (iii) mast cell-mediated tumor migration in vitro. Both our in vivo and in vitro studies suggest that mast cell-mediated inflammation could be 1 mechanism by which alcohol promotes carcinogenesis.

Cinnamon extract inhibits degranulation and de novo synthesis of inflammatory mediators in mast cells

BACKGROUND

Mast cells (MC) are main effector cells of allergic and other inflammatory reactions; however, only a few anti-MC agents are available for therapy. It has been reported that cinnamon extract (CE) attenuates allergic symptoms by affecting immune cells; however, its influence on MC was not studied so far. Here, we analyzed the effects of CE on human and rodent MC in vitro and in vivo.

METHODS

Expression of MC-specific proteases was examined in vivo in duodenum of mice following oral administration of CE. Release of mediators and phosphorylation of signaling molecules were analyzed in vitro in human MC isolated from intestinal tissue (hiMC) or RBL-2H3 cells challenged with CE prior to stimulation by FcεRI cross-linking.

RESULTS

Following oral treatment with CE, expression of the mast cell proteases MCP6 and MC-CPA was significantly decreased in mice. In hiMC, CE also caused a reduced expression of tryptase. Moreover, in hiMC stimulated by IgE cross-linking, the release of β-hexosaminidase was reduced to about 20% by CE. The de novo synthesis of cysteinyl leukotrienes, TNFα, CXCL8, CCL2, CCL3, and CCL4, was almost completely inhibited by CE. The attenuation of mast cell mediators by CE seems to be related to particular signaling pathways, because we found that activation of the MAP kinases ERK, JNK, and p38 as well as of Akt was strongly reduced by CE.

CONCLUSION

CE decreases expression of mast cell-specific mediators in vitro and in vivo and thus is a new plant-originated candidate for anti-allergic therapy.

The Protective Effect of Quercetin-3-O-β-D-Glucuronopyranoside on Ethanol-induced Damage in Cultured Feline Esophageal Epithelial Cells

Quercetin-3-O-β-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. We aimed to explore its protective effect against ethanol-induced cell damage and the mechanism involved in the effect in feline esophageal epithelial cells (EEC). Cell viability was tested and 2',7'-dichlorofluorescin diacetate assay was used to detect intracellular H₂O₂ production. Western blotting analysis was performed to investigate MAPK activation and interleukin 6 (IL-6) expression. Exposure of cells to 10% ethanol time-dependently decreased cell viability. Notably, exposure to ethanol for 30 min decreased cell viability to 43.4%. When cells were incubated with 50 µM QGC for 12 h prior to and during ethanol treatment, cell viability was increased to 65%. QGC also inhibited the H₂O₂ production and activation of ERK 1/2 induced by ethanol. Pretreatment of cells with the NADPH oxidase inhibitor, diphenylene iodonium, also inhibited the ethanol-induced ERK 1/2 activation. Treatment of cells with ethanol for 30 or 60 min in the absence or presence of QGC exhibited no changes in the IL-6 expression or release compared to control. Taken together, the data indicate that the cytoprotective effect of QGC against ethanol-induced cell damage may involve inhibition of ROS generation and downstream activation of the ERK 1/2 in feline EEC.

Hypoxia inducible factor-1α expression in areca quid chewing-associated oral squamous cell carcinomas

OBJECTIVES

Hypoxia inducible factor (HIF)-1α gene expression is mainly induced by tissue hypoxia. Overexpression of HIF-1α has been demonstrated in a variety of cancers. The aim of this study was to compare HIF-1α expression in normal human oral epithelium and areca quid chewing-associated oral squamous cell carcinoma (OSCC) and further to explore the potential mechanisms that may lead to induce HIF-1α expression.

METHODS

Twenty-five OSCC from areca quid chewing-associated OSCC and 10 normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry. The oral epithelial cell line GNM cells were challenged with arecoline, a major areca nut alkaloid, by using Western blot analysis. Furthermore, glutathione precursor N-acetyl-l-cysteine (NAC), AP-1 inhibitor curcumin, extracellular signal-regulated protein kinase inhibitor PD98059, and protein kinase C inhibitor staurosporine were added to find the possible regulatory mechanisms.

RESULTS

Hypoxia inducible factor-1α expression was significantly higher in OSCC specimens than normal specimen (P<0.05). Arecoline was found to elevate HIF-1α expression in a dose- and time-dependent manner (P<0.05). The addition of NAC, curcumin, PD98059, and staurosporine markedly inhibited the arecoline-induced HIF-1α expression (P<0.05).

CONCLUSIONS

Hypoxia inducible factor-1α expression is significantly upregulated in areca quid chewing-associated OSCC and HIF-1α expression induced by arecoline is downregulated by NAC, curcumin, PD98059, and staurosporine.

Effect of fluoride on calcium ion concentration and expression of nuclear transcription factor kappa-B ρ65 in rat hippocampus

The study investigated the neurotoxicity of drinking water fluorosis in rat hippocampus. Just weaning male Sprague-Dawley (SD) rats were given 15, 30, 60 mg/L NaF solution and tap water for 9 months. The calcium ion concentration ([Ca(2+)]) in synaptosomes was measured by double wavelength fluorescence spectrophotometer and the expression level of nuclear transcription factor kappa-B ρ65 (NF-κB ρ65) in hippocampal CA3 region was measured by immunohistochemistry. The results showed that [Ca(2+)] significantly increased (F = 33.218, P < 0.01) in moderate fluoride group compared with the control group, and the expression level of NF-κB ρ65 in CA3 region presented an increasing trend as fluoride concentration increased. These results indicate that increase of synaptosomes [Ca(2+)] and NF-κB ρ65 expression level may be the molecular basis of central nervous system damage caused by chronic fluoride intoxication. NF-κB ρ65 in CA3 region is probably a target molecule for fluorosis.

Inflammation and insulin resistance induced by trans-10, cis-12 conjugated linoleic acid depend on intracellular calcium levels in primary cultures of human adipocytes

We previously demonstrated that trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) induced inflammation and insulin resistance in primary human adipocytes by activating nuclear factor kappaB (NFkappaB) and extracellular signal-related kinase (ERK) signaling. In this study, we demonstrated that the initial increase in intracellular calcium ([Ca2+]i) mediated by 10,12 CLA was attenuated by TMB-8, an inhibitor of calcium release from the endoplasmic reticulum (ER), by BAPTA, an intracellular calcium chelator, and by D609, a phospholipase C (PLC) inhibitor. Moreover, BAPTA, TMB-8, and D609 attenuated 10,12 CLA-mediated production of reactive oxygen species (ROS), activation of ERK1/2 and cJun-NH2-terminal kinase (JNK), and induction of inflammatory genes. 10,12 CLA-mediated binding of NFkappaB to the promoters of interleukin (IL)-8 and cyclooxygenase (COX)-2 and induction of calcium-calmodulin kinase II (CaMKII) beta were attenuated by TMB-8. KN-62, a CaMKII inhibitor, also suppressed 10,12 CLA-mediated ROS production and ERK1/2 and JNK activation. Additionally, KN-62 attenuated 10,12 CLA induction of inflammatory and integrated stress response genes, increase in prostaglandin F2alpha, and suppression of peroxisome proliferator activated receptor gamma protein levels and insulin-stimulated glucose uptake. These data suggest that 10,12 CLA increases inflammation and insulin resistance in human adipocytes, in part by increasing [Ca2+]i levels, particularly calcium from the ER.

Polymorphisms in the promoter region of the human class II alcohol dehydrogenase (ADH4) gene affect both transcriptional activity and ethanol metabolism in Japanese subjects

Class II alcohol dehydrogenase (pi-ADH), encoded by alcohol dehydrogenase (ADH4), is considered to contribute to ethanol (EtOH) oxidation in the liver at high concentration. Four single nucleotide polymorphisms (SNPs) were found in the promoter region of this gene. Analysis of genotype distribution in 102 unrelated Japanese subjects revealed that four loci were in strong linkage disequilibrium and could be classified into three haplotypes. The effects of these polymorphisms on transcriptional activity were investigated in HepG2 cells. Transcriptional activity was significantly higher in cells with the -136A allele than in those with the -136C allele. To investigate whether this difference in transcriptional activity caused a difference in EtOH elimination, previous data on blood EtOH changes after 0.4 g/kg body weight alcohol ingestion were analyzed. When analyzed based on aldehyde dehydrogenase-2 gene (ALDH2) (487)Glu/Lys genotype, the significantly lower level of EtOH at peak in subjects with -136C/A and -136A/A genotype compared with subjects with -136C/C genotype indicated that -136 bp was a suggestive locus for differences in EtOH oxidation. This effect was observed only in subjects with ALDH2 (487)Glu/Glu. These results suggested that the SNP at -136bp in the ADH4 promoter had an effect on transcriptional regulation, and that the higher activity of the -136A allele compared with the -136C allele caused a lower level of blood EtOH after alcohol ingestion; that is, individuals with the -136A allele may consume more EtOH and might have a higher risk for development of alcohol dependence than those without the -136A allele.

Ethanol-TGFalpha-MEK signaling promotes growth of human hepatocellular carcinoma

BACKGROUND

Chronic ethanol intake is a significant risk factor for the development of cirrhosis and hepatocellular carcinoma (HCC). The effects of ethanol on extracellular signal-regulated kinase (ERK) activation, transforming growth factor alpha (TGF-alpha), and HCC growth were examined in this study.

METHODS

HepG2, SKHep, Hep3B human HCC cells, or normal human hepatocytes were treated with ethanol (0-100 mM), exogenous TGF-alpha, TGF-alpha neutralization antibody or the MEK inhibitor U0126. TGF-alpha levels were quantified by ELISA. Growth was determined by trypan blue-excluded cell counts. Cell cycle phase distribution was determined by flow cytometry. Protein expression was determined by Western blot.

RESULTS

Ethanol treatment (10-40 mM) increased ERK activation in HepG2 and SKHep HCC cells but not in Hep3B or human hepatocyte cells. Growth increased in HepG2 (174 +/- 29%, P < 0.05) and SKHep (149 +/- 12%, P < 0.05) cells in response to ethanol treatment. Correspondingly, ethanol increased S phase distribution in these cells. U0126 suppressed ethanol-induced growth increases. Ethanol treatment for 24 h also raised TGF-alpha levels in HepG2 cells (118%-198%) and SKHep cells (112%-177%). Exogenous administration of recombinant TGF-alpha mimicked the ethanol-induced growth in HepG2 and SKHep cells; TGF-alpha neutralization antibody effectively abrogated this effect. The TGF-a neutralization antibody also prevented ERK activation by ethanol in HepG2 cells.

CONCLUSIONS

These data demonstrate that clinically relevant doses of ethanol stimulate ERK-dependent proliferation of HCC cells. Ethanol up-regulates TGF-alpha levels in HCC cells and enhances growth through cell cycles changes, which appear to be mediated through TGF-alpha-MEK-ERK signaling. Ethanol-MEK signaling in normal hepatocytes is absent, suggesting that ethanol promotion of HCC growth may in part depend upon the acquisition of cancer-specific signaling by hepatocytes.

Expression of hypoxia-inducible factor-1 alpha is significantly associated with the progression and prognosis of oral squamous cell carcinomas in Taiwan

BACKGROUND

Overexpression of hypoxia-inducible factor-1 alpha (HIF-1 alpha) has been found to be significantly associated with the tumor invasion, lymph node metastasis, clinical stage, and prognosis of a variety of human cancers.

METHODS

This study examined the expression of HIF-1 alpha in 57 specimens of oral squamous cell carcinoma (OSCC), 41 specimens of oral epithelial dysplasia (OED, 12 mild, 17 moderate, and 12 severe OED cases), and 14 specimens of normal oral mucosa (NOM) by immunohistochemistry.

RESULTS

We found that the mean nuclear HIF-1 alpha labeling indices (LIs) increased significantly from NOM (9 +/- 6%) through mild OED (25 +/- 18%), moderate OED (41 +/- 27%), and severe OED (42 +/- 22%) to OSCC samples (55 +/- 23%, P < 0.001). A significant correlation was found between the higher mean nuclear HIF-1 alpha LI and OSCCs with larger tumor size (P < 0.001), regional lymph node metastasis (P < 0.001), or more advanced clinical stages (P < 0.001). Only larger tumor size (P = 0.002) and nuclear HIF-1 alpha LI >or= 60% (P = 0.048) were identified as independent unfavorable prognosis factor by multivariate analyses with Cox regression model. Kaplan-Meier curve showed that OSCC patients with a nuclear HIF-1 alpha LI >or= 60% had a significantly poorer cumulative survival than those with a nuclear HIF-1 alpha LI < 60% (log-rank test, P = 0.022).

CONCLUSIONS

We conclude that the expression of HIF-1 alpha is an early event in oral carcinogenesis. The nuclear HIF-1 alpha LI in OSCC samples can predict the progression of OSCCs and the survival of OSCC patients.

Contribution of TRPV1 to microglia-derived IL-6 and NFkappaB translocation with elevated hydrostatic pressure

PURPOSE

The authors investigated the contributions of the transient receptor potential vanilloid-1 receptor (TRPV1) and Ca(2+) to microglial IL-6 and nuclear factor kappa B (NFkappaB) translocation with elevated hydrostatic pressure.

METHODS

The authors first examined IL-6 colocalization with the microglia marker Iba-1 in the DBA/2 mouse model of glaucoma to establish relevance. They isolated microglia from rat retina and maintained them at ambient or elevated (+70 mm Hg) hydrostatic pressure in vitro and used ELISA and immunocytochemistry to measure changes in the IL-6 concentration and NFkappaB translocation induced by the Ca(2+) chelator EGTA, the broad-spectrum Ca(2+) channel inhibitor ruthenium red, and the TRPV1 antagonist iodo-resiniferatoxin (I-RTX). They applied the Ca(2+) dye Fluo-4 AM to measure changes in intracellular Ca(2+) at elevated pressure induced by I-RTX and confirmed TRPV1 expression in microglia using PCR and immunocytochemistry.

RESULTS

In DBA/2 retina, elevated intraocular pressure increased microglial IL-6 in the ganglion cell layer. Elevated hydrostatic pressure (24 hours) increased microglial IL-6 release, cytosolic NFkappaB, and NFkappaB translocation in vitro. These effects were reduced substantially by EGTA and ruthenium red. Antagonism of TRPV1 in microglia partially inhibited pressure-induced increases in IL-6 release and NFkappaB translocation. Brief elevated pressure (1 hour) induced a significant increase in microglial intracellular Ca(2+) that was partially attenuated by TRPV1 antagonism.

CONCLUSIONS

Elevated pressure induces an influx of extracellular Ca(2+) in retinal microglia that precedes the activation of NFkappaB and the subsequent production and release of IL-6 and is at least partially dependent on the activation of TRPV1 and other ruthenium red-sensitive channels.

Quercetin protects human hepatocytes from ethanol-derived oxidative stress by inducing heme oxygenase-1 via the MAPK/Nrf2 pathways

BACKGROUND/AIMS

Flavonoids, including quercetin, have been reported to have potent hepatoprotective effects, which may be associated with HO-1 induction. However, since the effect and signaling pathway of quercetin involved in HO-1 induction against alcoholic liver damage are still not fully understood, this is the target of the present study.

METHODS

Human hepatocytes were incubated with ethanol (100 mM) and quercetin (10-200 microM), and cellular damage and HO-1 activity were measured. Nrf2 expression in cytosolic and nuclear fractions was studied following the incubation with MAPK inhibitor(s).

RESULTS

Ethanol exposure resulted in a sustained glutathione depletion, malondialdehyde elevation, and evident release of cellular LDH and AST. Quercetin exerted a dose-dependent protective effect against alcoholic oxidative stress, and increased the EC50 of ethanol by approx. 40%, which is parallel to HO-1 induction with quercetin. Zinc protoporphyrin-9 abrogated the protective effect and dramatically enhanced ethanol cytotoxicity. SB203580 (p38 inhibitor) and especially PD98059 (ERK inhibitor) blocked quercetin-derived HO-1 induction and Nrf2 translocation, and subsequently inhibited the quercetin-related protection.

CONCLUSIONS

HO-1 up-regulation by quercetin protected human hepatocytes from ethanol-induced oxidative stress. Among MAPK signaling pathways, p38 and ERK mediated quercetin-derived Nrf2 translocation into nuclei and subsequent induction of HO-1 activity, and the latter showed a stronger mediating effect.

Is pyruvate an endogenous anti-inflammatory molecule?

Pyruvic acid is an effective scavenger of reactive oxygen species. Ethyl pyruvate has demonstrated anti-inflammatory actions and improved hyperpermeability and bacterial translocation due to endotoxemia and is of benefit in animal models of sepsis and septic shock. Ethyl pyruvate specifically inhibits tumor necrosis factor-alpha production and decreases circulating levels of high-mobility group box-1 and nuclear factor-kappaB signaling pathways by specifically targeting its p65 subunit in animals with established endotoxemia or sepsis and in macrophage cultures. Ethyl pyruvate also decreases cyclo-oxygenase-2, inducible nitric oxide synthase, and interleukin-6 mRNA expression in the liver, ileal mucosa, and colonic mucosa in animal models with hemorrhagic shock. Similar beneficial actions have been seen in endotoxemia. These and other studies suggest that ethyl pyruvate could be of significant benefit in the treatment of patients who are critically ill and have sepsis/septic shock.

Toward understanding the genetics of alcohol drinking through transcriptome meta-analysis

Much evidence from studies in humans and animals supports the hypothesis that alcohol addiction is a complex disease with both hereditary and environmental influences. Molecular determinants of excessive alcohol consumption are difficult to study in humans. However, several rodent models show a high or low degree of alcohol preference, which provides a unique opportunity to approach the molecular complexities underlying the genetic predisposition to drink alcohol. Microarray analyses of brain gene expression in three selected lines, and six isogenic strains of mice known to differ markedly in voluntary alcohol consumption provided >4.5 million data points for a meta-analysis. A total of 107 arrays were obtained and arranged into six experimental data sets, allowing the identification of 3,800 unique genes significantly and consistently changed between all models of high or low amounts of alcohol consumption. Several functional groups, including mitogen-activated protein kinase signaling and transcription regulation pathways, were found to be significantly overrepresented and may play an important role in establishing a high level of voluntary alcohol drinking in these mouse models. Data from the general meta-analysis was further filtered by a congenic strain microarray set, from which cis-regulated candidate genes for an alcohol preference quantitative trait locus on chromosome 9 were identified: Arhgef12, Carm1, Cryab, Cox5a, Dlat, Fxyd6, Limd1, Nicn1, Nmnat3, Pknox2, Rbp1, Sc5d, Scn4b, Tcf12, Vps11, and Zfp291 and four ESTs. The present study demonstrates the use of (i) a microarray meta-analysis to analyze a behavioral phenotype (in this case, alcohol preference) and (ii) a congenic strain for identification of cis regulation.