Sulfur mustard upregulates the expression of interleukin-8 in cultured human keratinocytes

Validation of automated pipetting systems for cell culture seeding, exposure and bio-analytical assays in sulfur mustard toxicology

In vitro cell culture experiments are highly important techniques to accelerate drug discovery, conduct safety testing and reduce the need for animal studies. Therefore, automatization may help to enhance the technical precision, reduce external (including operator's) influence on the data and thus improve reliability. Prior to application in scientific studies, validation of automated systems is absolutely necessary. In this study we present the validation of two combined automated pipetting systems to conduct toxicity studies in HaCaT cells consisting of cell seeding, noxious agent exposure and several assays to assess cell survival, apoptosis and interleukin production. After initial validation of pipetting accuracy, we compared homogeneity after automated seeding to plates seeded by expert laboratory technicians. Moreover, automated dispensing of a potentially unstable noxious agent was analyzed in terms of speed and consistency. We found a 2 % technical imprecision for the cell survival assay and 4.5-6 % for the other assays, bioluminescent and ELISA techniques. Thus, we could demonstrate the excellent technical precision of our assays. In a final step, we found that intraday variations, though acceptable, were much larger than technical variations and had to assume an intraday biological variability between different wells of the same experimental group.

Nitrogen mustard prevents transport of Fra-1 into the nucleus to promote c-Fos- and FosB-dependent IL-8 induction in injured mouse epidermis

Transcription factor activator protein (AP)-1 can be activated in nitrogen-mustard-injured mouse skin, and is thought to participate in the inflammatory response. AP-1 consists of homo- or heterodimers of Fos [c-Fos, Fos-B, fos-related antigen (Fra)-1 and Fra-2] and Jun (c-Jun, JunB and JunD) family members, and information about their expression, location and function are still unclear. In nitrogen-mustard-exposed mouse skin, we found p-ERK activation increased Fra-1 and FosB. Unlike the nucleus location of c-Fos and FosB, Fra-1 and Fra-2 were mainly expressed in the cytoplasm. In nitrogen-mustard-exposed cultured immortalized human keratinocytes (HaCaT cells), Fra-1 in the nucleus functioned as an inhibitor of inflammatory cytokine interleukin (IL)-8. Co-immunoprecipitation showed that Fra-1 formed dimers with IL-8 transcription factors c-Jun, JunB and JunD. Fra-1 depletion increased c-Fos and FosB in the nucleus, accompanied by increased heterodimers of c-Fos/c-Jun, c-Fos/JunB, c-Fos/JunD, and FosB/JunB. In conclusion, Fra-1 trapped in the cytoplasm after nitrogen mustard exposure might be a driving force for IL-8 over-expression in injured skin.

Necrosulfonamide - Unexpected effect in the course of a sulfur mustard intoxication

Although its first military use in Ypres was 100 years ago, no causal therapy for sulfur mustard (SM) intoxications exists so far. To improve the therapeutic options for the treatment of SM intoxications, we developed a co-culture of keratinocytes (HaCaT cells) and immunocompetent cells (THP-1 cells) to identify potential substances for further research. Here, we report on the influence of necrosulfonamide (NSA) on the course of a SM intoxication in vitro. The cells were challenged with 100, 200 and 300 μM SM and after 1 h treated with NSA (1, 5, 10 μM). NSA was chosen for its known ability to inhibit necroptosis, a specialized pathway of programmed necrosis. However, in our settings NSA showed only mild effects on necrotic cell death after SM intoxication, whereas it had an immense ability to prevent apoptosis. Furthermore, NSA was able to reduce the production of interleukin-6 and interleukin-8 at certain concentrations. Our data highlight NSA as a candidate compound to address cell death and inflammation in SM exposure.

Anti-apoptotic and moderate anti-inflammatory effects of berberine in sulfur mustard exposed keratinocytes

Skin affections after sulfur mustard (SM) exposure include erythema, blister formation and severe inflammation. An antidote or specific therapy does not exist. Anti-inflammatory compounds as well as substances counteracting SM-induced cell death are under investigation. In this study, we investigated the benzylisoquinoline alkaloide berberine (BER), a metabolite in plants like berberis vulgaris, which is used as herbal pharmaceutical in Asian countries, against SM toxicity using a well-established in vitro approach. Keratinocyte (HaCaT) mono-cultures (MoC) or HaCaT/THP-1 co-cultures (CoC) were challenged with 100, 200 or 300mM SM for 1h. Post-exposure, both MoC and CoC were treated with 10, 30 or 50μM BER for 24h. At that time, supernatants were collected and analyzed both for interleukine (IL) 6 and 8 levels and for content of adenylate-kinase (AK) as surrogate marker for cell necrosis. Cells were lysed and nucleosome formation as marker for late apoptosis was assessed. In parallel, AK in cells was determined for normalization purposes. BER treatment did not influence necrosis, but significantly decreased apoptosis. Anti-inflammatory effects were moderate, but also significant, primarily in CoC. Overall, BER has protective effects against SM toxicity in vitro. Whether this holds true should be evaluated in future in vivo studies.

Pro-oxidant-antioxidant balance in Iranian veterans with sulfur mustard toxicity and different levels of pulmonary disorders

OBJECTIVE

Sulfur mustard (SM) is a strong alkylating agent that primarily targets the skin, eye and lung. The current study evaluated the pro-oxidant-antioxidant balance (PAB) assay in human serum of SM-exposed patients.

DESIGN AND METHODS

sera of 35 SM-exposed patients and 19 healthy volunteers were recruited. Both groups had nonsmoker and nonalcoholic people with no diseases such as diabetes, heart disease and other pulmonary diseases (COPD because of smoking, asthma and so on). All patients had documented exposure to SM. The PAB was measured.

RESULTS

SM-exposed patients with normal values for pulmonary function test and severe obstructive pulmonary disease demonstrated a significant increase in PAB value in compared with healthy volunteers (the PAB values in healthy volunteers, normal and severe patients were 48.74 ± 21.07 HK, 101.45 ± 32.68 HK and 120.23 ± 31.55 HK, respectively). However, the level of oxidation is not related to the severity of disease defined by spirometry findings. A significant negative correlation was established between the PAB value and FEV1.

CONCLUSIONS

The increased PAB value in chemical casualties showed that these patients are exposed to oxidative stress.

A randomized controlled trial on the anti-inflammatory effects of curcumin in patients with chronic sulphur mustard-induced cutaneous complications

Background

Chronic cutaneous complications such as pruritus are among the very frequent complaints of sulphur mustard (SM)-exposed patients. The present trial investigated the impact of curcumin on serum inflammatory biomarkers and their association with pruritus severity and quality of life (QoL).

Methods

This was a randomized, double-blind trial among 96 male Iranian veterans (age 37–59 y) who were suffering from chronic SM-induced pruritic skin lesions. Patients were randomly assigned to curcumin (1 g/d, n = 46) or placebo ( n = 50) for four weeks. Serum concentrations of interleukins 6 (IL-6) and 8 (IL-8) together with high-sensitivity C-reactive protein (hs-CRP) and calcitonin gene-related peptide (CGRP) were measured at baseline and at the end of the trial. Assessment of pruritus severity was performed using the pruritus score and QoL using the Dermatology Life Quality Index (DLQI).

Results

Serum IL-8 and hs-CRP were significantly reduced in both groups but the magnitude of reduction was greater in the curcumin group ( P < 0.001). Serum CGRP was only decreased in the curcumin group ( P < 0.001). No significant change was observed in serum IL-6. There were significant correlations between CGRP and IL-6 changes ( P = 0.011) and between DLQI and IL-8 changes ( P = 0.026) in the curcumin group. In the curcumin group, changes in serum IL-8 concentrations were found as the significant predictor of DLQI scores ( P = 0.026) but none of the independent variables could predict pruritus scores.

Conclusions

Curcumin supplementation effectively mitigates inflammation in patients suffering from chronic SM-induced cutaneous complications. This anti-inflammatory effect might account for the observed pruritus alleviation and QoL improvement by this phytochemical.

Sulfur mustard vapor effects on differentiated human lung cells

CONTEXT

Sulfur mustard (SM) causes skin blistering and long-term pulmonary dysfunction. Its adverse effects have been studied in battlefield-exposed humans, but lack of knowledge regarding confounding factors makes interpretation challenging. Animal studies are critical to understanding mechanisms, but differences between animals and humans must be addressed. Studies of cultured human cells can bridge animal studies and humans.

OBJECTIVE

Evaluate effects of SM vapor on airway cells.

MATERIALS AND METHODS

We examined responses of differentiated human tracheal/bronchial epithelial cells, cultured at an air-liquid interface, to SM vapors. SM effects on metabolic activity (Water Soluble Tetrazolium (WST) assay), cytokine and metalloproteinase secretion, and cellular heme oxygenase 1 (HO-1), an oxidative stress indicator, were measured after 24 h.

RESULTS

At noncytotoxic levels of exposure, interleukin 8 and matrix metalloproteinase-13 were significantly increased in these cultures, but HO-1 was not significantly affected.

DISCUSSION AND CONCLUSION

Exposure of differentiated airway epithelial cells to sub-cytotoxic levels of SM vapor induced inflammatory and degradative responses that could contribute to the adverse health effects of inhaled SM.

Attenuation of sulfur mustard toxicity by S-2(2-aminoethylamino)ethyl phenyl sulfide (DRDE-07) in mouse liver

Sulfur mustard (SM) (bis-(2-chloroethyl) sulfide) is a chemical warfare agent. Evaluation of toxicity and protective effect of DRDE-07 (S-2(2-aminoethylamino)ethyl phenyl sulfide) was studied in mouse liver after SM challenging. Female mice were given orally 0.2 LD(50) of DRDE-07 (249 mg/kg body weight) and exposed percutaneously with 1.0 LD(50) of SM (8.1 mg/kg body weight). Gene expression profiles were determined using global genome microarray analysis at 3 days post-exposure. DRDE-07 alone treated animal showed significant upregulation to metabolism of xenobiotics by cytochrome P450 pathways. Genes related to cell adhesion molecules (CAMs), were downregulated. DRDE-07 pretreated SM exposed animals showed upregulation of xenobiotic cytochrome P450 pathway genes. Antigen presenting, cell adhesion molecules, cytokine, cytokine receptor metabolism, fatty acid metabolism, glutathione metabolism, cell cycle signaling pathway genes showed downregulation. The present study showed that SM-induced toxicity in mouse liver was attenuated by the pretreatment with DRDE-07.

Sulfur mustard toxicity: history, chemistry, pharmacokinetics, and pharmacodynamics

Sulfur mustard (SM) and similar bifunctional agents have been used as chemical weapons for almost 100 years. Victims of high-dose exposure, both combatants and civilians, may die within hours or weeks, but low-dose exposure causes both acute injury to the eyes, skin, respiratory tract and other parts of the body, and chronic sequelae in these organs are often debilitating and have a serious impact on quality of life. Ever since they were first used in warfare in 1917, SM and other mustard agents have been the subjects of intensive research, and their chemistry, pharmacokinetics and mechanisms of toxic action are now fairly well understood. In the present article we review this knowledge and relate the molecular-biological basis of SM toxicity, as far as it has been elucidated, to the pathological effects on exposure victims.

Ocular effects of exposure to industrial chemicals: clinical management and proteomic approaches to damage assessment

Industrial chemicals in a variety of applications are often found in highly populated areas and their presence carries risks. The threat of serious consequences from inadvertent or intentional events involving hazardous chemicals is a possibility. Extremism and/or other illicit activities pose environmental threats from chemical exposures. We present here a review of the threat of ocular injury in small-and large-scale chemical releases and discuss mechanisms of damage and repair to the eyes. The emerging field of proteomics has been described in relation to its potential role in the assessment of ocular changes following chemical exposures and management of ocular trauma.

Induction of interleukin-8 expression in porcine peripheral blood mononuclear cells by trans10-cis12 conjugated linoleic acid

The chemotaxis of porcine peripheral blood polymorphonuclear cells (PMN) was enhanced by culture supernatant from peripheral blood mononuclear cells (PBMC) treated with trans10-cis12 (10t-12c) conjugated linoleic acid (CLA) or by porcine recombinant (pr) interleukin (IL)-8. To identify this chemotactic inducing factor, the culture supernatant from 10t-12c CLA treated PBMC was partially purified by gel filtration. Only fraction 9 contained enhanced PMN chemotactic activity. The chemotactic activity of fraction 9 was inhibited by an anti-prIL-8 polyclonal antibody (pAb). Porcine IL-8 mRNA expression analyzed by a reverse transcriptase-polymerase chain reaction (RT-PCR) assay was increased in PBMC by the addition of 10t-12c CLA. This study strongly suggests that the immunoenhancing effect of CLA on the chemotactic response of porcine PMN is mediated through IL-8 produced by CLA treated PBMC.

Microarray Analysis of Mouse Ear Tissue Exposed to Bis-(2-chloroethyl) Sulfide: Gene Expression Profiles Correlate with Treatment Efficacy and An Established Clinical Endpoint

Bis-(2-chloroethyl) sulfide (sulfur mustard; SM) is a potent alkylating agent. Three treatment compounds have been shown to limit SM damage in the mouse ear vesicant model: dimercaprol, octyl homovanillamide, and indomethacin. Microarrays were used to determine gene expression profiles of biopsies taken from mouse ears after exposure to SM in the presence or absence of treatment compounds. Mouse ears were topically exposed to SM alone or were pretreated for 15 min with a treatment compound and then exposed to SM. Ear tissue was harvested 24 h after exposure for ear weight determination, the endpoint used to evaluate treatment compound efficacy. RNA extracted from the tissues was used to generate microarray probes for gene expression profiling of therapeutic responses. Principal component analysis of the gene expression data revealed partitioning of the samples based on treatment compound and SM exposure. Patterns of gene responses to the treatment compounds were indicative of exposure condition and were phenotypically anchored to ear weight. Pretreatment with indomethacin, the least effective treatment compound, produced ear weights close to those treated with SM alone. Ear weights from animals pretreated with dimercaprol or octyl homovanillamide were more closely associated with exposure to vehicle alone. Correlation coefficients between gene expression level and ear weight revealed genes involved in mediating responses to both SM exposure and treatment compounds. These data provide a basis for elucidating the mechanisms of response to SM and drug treatment and also provide a basis for developing strategies to accelerate development of effective SM medical countermeasures.

Egg white derivatives induce tumor necrosis factor-α expression in porcine peripheral blood mononuclear cells

Porcine PBMC derived phagocytic activity in peripheral blood polymorphonuclear cells (PMN) induced by egg white derivatives (EWD) treatment was analyzed at the protein and mRNA level. EWD alone failed to induce phagocytic activity of PMN measured by flow cytometry. But PMN phagocytosis was enhanced by culture supernatant from PBMC treated with EWD, human (h)rTNF-alpha and porcine (p)rIL-1beta, respectively. To identify this phagocytic inducing factor, the culture supernatant was partially purified by gel filtration. Only fraction 8 revealed the enhanced PMN phagocytic activity. This fraction also had a high cross-reactivity with anti-prTNF-alpha polyclonal (p)Ab but not with anti-prIL-1beta pAb, as measured by ELISA, indicating that the culture supernatant from PBMC treated with EWD was independent from IL-1beta. The enhanced PMN phagocytic activity of fraction 8 was also inhibited by anti-prTNF-alpha pAb. Both fraction 8 and hrTNF-alpha produced a single protein band between 16 and 18kDa upon analysis by sodium-dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting using anti-prTNF-alpha pAb, suggesting that the promoter of PMN phagocytosis is TNF-alpha, a 16-18 kDa protein produced by EWD-stimulated PBMC. Porcine TNF-alpha mRNA expression in porcine PBMC analyzed by RT-PCR was also increased by addition of EWD. This study strongly suggests that the immunoenhancing effect of EWD on the phagocytic response of porcine PMN is mediated through TNF-alpha produced by PBMC stimulated with EWD. In addition, the expression of porcine TNF-alpha on PBMC is also increased when stimulated with EWD.

Modulation of sulfur mustard induced cell death in human epidermal keratinocytes using IL-10 and TNF-α

We compared the effects of overexpressing a tightly regulated anti-inflammatory cytokine, interleukin 10 (IL-10), and the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) on sulfur mustard induced cytotoxicity in human epidermal keratinocytes. Both cytokines were overexpressed when compared with the cells transfected with the empty vector as determined by quantitative ELISA. Cells overexpressing interleukin 10 suppressed the pro-inflammatory cytokines interleukin 8 and interleukin 6 following exposure to 50-300 microM sulfur mustard. These cells exhibited delayed onset of sulfur mustard induced cell death. On the other hand, cells overexpressing tumor necrosis factor alpha induced a sustained elevation in both interleukin 6 and 8 expression following exposure to 50-300 microM sulfur mustard. These cells were sensitized to the effects of sulfur mustard that resulted in an increased sulfur mustard induced cell death. Normal human epidermal keratinocytes treated with sulfur mustard exhibited elevated levels of tumor necrosis factor alpha expression and increased activity of nuclear factor kappa B. Gene array data indicated that cells overexpressing interleukin 10 induced several genes that are involved in growth promotion and cell-fate determination. We, therefore, identify IL-10 and TNF-alpha signal transduction pathways and their components as possible candidates for early therapeutic intervention against sulfur mustard induced cell injury.

An inhibitor of p38 MAP kinase downregulates cytokine release induced by sulfur mustard exposure in human epidermal keratinocytes

Sulfur mustard (2,2'-dichlorodiethyl sulfide, SM) is a potent alkylating agent that induces skin vessication after cutaneous exposure. Previous work has revealed that SM induces the production of inflammatory cytokines, including IL-8, IL-6, TNF-alpha, and IL-1beta, in keratinocytes. The p38 MAP kinase (MAPK14) signaling pathway is activated via phosphorylation in response to cellular stress and has been implicated in the upregulation of cytokines in response to stress. We investigated the role of p38 MAP kinase in inflammatory cytokine upregulation following SM exposure. A dose response study in cultured human epidermal keratinocytes (HEK) revealed increasing phosphorylation of p38 MAP kinase in response to increasing concentrations of SM. A time course at the 200 microM exposure revealed that p38 MAP kinase phosphorylation is induced by 15 min post-exposure, peaks at 30 min and is sustained at peak levels until 8 h post-exposure. Phosphorylation of the upstream kinase MKK3/6 was also detected. Assay of the SM-exposed HEK culture media for cytokines revealed that exposure to 200 microM SM increased IL-8, IL-6, TNF-alpha, and IL-1beta. When cells exposed to 200 microM SM were treated with the p38 MAP kinase inhibitor SB203580, the levels of IL-8, IL-6, and TNF-alpha and IL-1beta were significantly decreased when compared with cells that were untreated. These results show that p38 MAP kinase plays a role in SM-induced cytokine production in HEK and suggest that inhibiting this pathway may alleviate the profound inflammatory response elicited by cutaneous SM exposure.

Cytokine, chemokine, and matrix metalloproteinase response after sulfur mustard injury to weanling pig skin

Cutaneous exposure to sulfur mustard [bis(2-chloroethyl) sulfide; SM] produces a delayed inflammatory skin response and severe tissue injury. Pig skin has organ similarities to human skin that is characterized by the content and types of epidermal lipids, the density of hair follicles and presence of sweat glands, which together afford penetration of topically applied compounds, complex inflammatory responses, and subsequent wound healing. The goal of this study was to identify in vivo proinflammatory biomarkers of the SM porcine skin injury within 72 h after SM challenge, using the weanling pig model. Changes in gene expression of inflammatory mediators were examined at 3, 6, 24, 48, and 72 h, using subtraction library analyses and by quantitation of selected transcripts by reverse transcription-polymerase chain reaction (RT-PCR). Sequence analysis of subtraction libraries identified up-regulation of IL-8 at 24, 48, and 72 h. No other specific proinflammatory gene transcripts were isolated from the libraries. Specific transcript RT-PCR analysis showed increased production of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and matrix metalloproteinase-9 (MMP-9, gelatinase B) mRNA levels in response to SM exposure. Tumor necrosis factor-alpha (TNF-alpha) expression was only slightly increased and no change in the levels of expression was observed for monocyte chemoattractant protein-1 and MMP-2. This study identifies the main proinflammatory mediators involved in SM-induced skin injury in a weanling pig model. The results suggest transcriptional activity in the inflammatory response proteins IL-8, IL-6, IL-1beta, and MMP-9 and modest changes in TNF-alpha that together produce inflammation and contribute to the pathogenesis of SM dermatotoxicity. Therefore, drugs preventing SM-induced inflammation should be prime candidates for medical intervention to lessen collateral inflammation associated with tissue destruction.

Regulation of 1-alpha, 25-dihydroxyvitamin D3 on interleukin-6 and interleukin-8 induced by sulfur mustard (HD) on human skin cells

The regulatory effects of the active form of vitamin D, 1-alpha, 25-dihydroxyvitamin D3 (1-alpha, 25 (OH)2D3) were assessed on the cytokine and chemokine secretion induced by sulfur mustard on human skin fibroblasts and human epidermal keratinocytes. Stimulation of human skin fibroblasts with sulfur mustard (10(-4) M for 24 hr at 37 degrees ) resulted in approximately a 5 times increase in the secretion of interleukin-6 and over a 10 times increase for interleukin-8, which was inhibited by 1-alpha, 25 (OH)2D3, at <or=10(-9) M. 1-alpha, 25 (OH)2D3 also suppressed interleukin-8 secretion by 5 times and interleukin-6 by 4 times on sulfur mustard-stimulated human epidermal keratinocytes at concentrations <or= 10(-9) M. The effect of 1-alpha, 25 (OH)2D3 was dose-dependent for the suppression of interleukin-6 and interleukin-8 induced by sulfur mustard on human skin fibroblasts/human epidermal keratinocytes, apparent at nanomolar concentrations. Our results indicate that the suppression of these inflammatory mediators by 1-alpha, 25 (OH)2D3 is dependent on the source of the primary cultures, cell densities, and kinetics of pretreatments. In contrast to the inhibition of cytokine/chemokine production, cell proliferation was enhanced by almost 1.7 times on treated human epidermal keratinocytes with 1-alpha, 25 (OH)2D3 (1 x 10(-9) M) after sulfur mustard-stimulation (10(-4) M for 24 hr at 37 degrees C). The observed enhancement diversified based on cell density, and kinetics of pretreatment with a maximal synergism (s) observed at 1 x 10(-9) M. Photomicrographs show typical signs of cellular degeneration caused by sulfur mustard such as chromatin condensation. The observed cellular degeneration was lessened when human epidermal keratinocytes were treated with 1-alpha, 25 (OH)2D3 (2 x 10(-9) M). 1-alpha, 25(OH)2D3 could be an alternative treatment for cutaneous inflammation disorders caused by sulfur mustard because we have demonstrated its ability to suppress inflammatory mediators and enhanced cell proliferation in human skin cells stimulated with sulfur mustard.

Sulfur mustard-induced arachidonic acid release is mediated by phospholipase D in human keratinocytes

Sulfur mustard (2,2(')-dichloroethyl sulfide) is a chemical warfare agent that causes incapacitating skin blisters in humans 12-24h post-exposure following a variable asymptomatic phase. Recent reports demonstrate that inflammation plays a vital role in sulfur mustard toxicity. One of the key biochemical pathways involved in inflammation is the arachidonic acid cascade. In this report, we demonstrate that arachidonic acid is released in response to sulfur mustard and investigate the mechanisms of arachidonic acid release. Exposure to sulfur mustard caused a 5- to 8-fold increase in arachidonic acid release from human keratinocytes that had been radiolabeled with arachidonic acid. Maximal arachidonic acid release occurred between 12 and 24h. Several enzymatic pathways can lead to arachidonic acid release. Treatment with 2.0% (v/v) ethanol, an inhibitor of phospholipase D, decreased sulfur mustard-induced arachidonic acid release 40+/-7%. Additionally, 100 microM (+/-)-propranolol, an inhibitor of phosphatidic acid phosphohydrolase, blocked sulfur mustard-induced arachidonic acid release by 62+/-3%. These findings suggest that arachidonic acid release is mediated by phospholipase D and phosphatidic acid phosphohydrolase in human keratinocytes following sulfur mustard exposure. Due to the 12-24h delay in arachidonic acid release following sulfur mustard exposure, delayed therapeutic intervention may be possible. Indeed, we found that the addition of 100 microM (+/-)-propranolol up to 18 h after sulfur mustard exposure was still able to block arachidonic acid release by 30+/-3%.

Protection from half-mustard-gas-induced acute lung injury in the rat

The chemical warfare agent analog, 2-chloroethyl ethyl sulfide, known as 'half-mustard gas' (HMG), is less toxic and less of an environmental hazard than the full molecule and has been shown to produce an acute lung injury in rats when instilled via intrapulmonary injection. This injury is characterized by massive, localized hemorrhage and edema into the alveolar compartment and can be quantitated by measuring extravasation of (125)I-bovine serum albumin into the extravascular compartment. Employing this rat model of HMG-induced lung injury, we observed significant attenuation of the pulmonary injury when experimental animals were complement or neutrophil depleted prior to HMG challenge. Significant protection also was provided by the use of antioxidants such as catalase, dimethyl sulfoxide, dimethyl thiourea, resveratrol and N-acetyl-L-cysteine (NAC). The last compound showed protection from lung injury as high as 70% and was still effective even when given up to 90 min after exposure of the lungs to HMG. These data suggest that acute lung injury caused by exposure to HMG may be related partially to complement mediated pathways and the generation by neutrophils of toxic oxygen species The data indicate that NAC is an effective antidote against HMG-induced acute lung injury in the rat.

Feline interleukin-8 expression in peripheral blood mononuclear cells induced by egg white derivatives

Feline peripheral blood mononuclear cells (PBMC)-derived chemotactic factor induced by egg white derivatives (EWD) treatment was analyzed at the protein and messenger ribonucleic acid (mRNA) level. EWD itself was not active chemotactic for feline peripheral blood polymorphonuclear cells (PMN). But chemotaxis of PMN was enhanced by either culture supernatant from PBMC treated with EWD or human recombinant (hr) interleukin (IL)-8. Both hr IL-8 and the culture supernatant from PBMC treated with EWD yielded a distinct band, molecular weight of 6-8kDa, in sodium-dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with 15% loading gel. Therefore, to identify this chemotactic factor, culture supernatant from PBMC treated with EWD was partially purified by anion exchange chromatography on diethylaminoethyl (DEAE)-Sepharose CL-6B and concentrated by ultrafiltration. Only the fraction, which was eluted with 0.3M NaCl, showed a high concentration of total protein and also enhanced the chemotactic activity of PMN. This activity was thereafter designated as eluate. The chemotactic activity of eluate was inhibited by anti-hr IL-8 polyclonal antibody (pAb). A single protein band with 6-8kDa was shown in both the eluate and hr IL-8 when analyzed by SDS-PAGE and Western blotting using anti-hr IL-8 pAb, suggesting that the chemotactic factor for feline PMN is IL-8, 6-8kDa, produced by PBMC treated with EWD. The physicochemical characteristics of eluate were stable in heated (60-100 degrees C), acid (pH 3.0), and alkaline (pH 9.0) conditions. The eluate under these conditions also showed a distinct band in molecular weight of 6-8kDa in SDS-PAGE and Western blotting and was very active in chemotactic activity of PMN.IL-8 mRNA gene expression on feline PBMC was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) assay using a series of oligonucleotides, each 22 mer, derived from feline IL-8. Feline IL-8 mRNA showed low level in 3-h incubation without EWD, but it was increased in a dose-dependent manner by addition of EWD. Following EWD (10 microg/ml) treatment, IL-8 mRNA expression was rapidly increased up to 6h and decreased by 12h although it was not expressed in freshly prepared PBMC. This study strongly suggested that immunoenhancing effect of EWD on chemotactic response of PMN is mediated by feline IL-8, 6-8kDa, produced by PBMC stimulated with EWD. In addition, the expression of feline IL-8 mRNA on PBMC is increased when stimulated with EWD.

The role of interleukin-6 (IL-6) in human sulfur mustard (HD) toxicology

The authors applied in vitro models of controlled damage to human epidermal keratinocytes (HEKs), human skin fibroblasts (HSFs), and human breast skin tissue (HBST) to examine the mechanism responsible for sulfur mustard (HD)-induced interleukin-6 (IL-6) alterations. Treatment with 100 microM HD for 24 hours resulted in a significant increased amount of IL-6 being secreted by HEKs (HD-exposed to control ratio [E/C] = 4.15 +/- 0.07) and by HSFs (E/C = 7.66 +/- 0.04). Furthermore, the HD-induced secretion of IL-6 in HEKs was neutralized with monoclonal human IL-6 antibodies. The secretion of IL-6 in HBST supernatant exposed to HD produced conflicting results. Although an increase of IL-6 was observed in control superfusion media from HBST, IL-6 levels were observed to decrease as the concentration of HD increased. Time course of IL-6 mRNA levels were performed using a competitive polymerase chain reaction (PCR) and human IL-6 mRNA assay detection kit in control and HD (100 microM)-treated HEKs cells. IL-6 mRNA transcripts in HD-exposed HEKs were first observed within 2 hours, dropped at 5 to 6 hours, and increased by approximately 2.2-fold and 8.5-fold at 24 to 48 hours after HD exposure, respectively, as detected by the Xplore mRNA Quantification System. Surface-enhanced laser desorption ionization (SELDI) mass spectrometry was also applied to study the secretion pattern of IL-6 on lysate preparations of HBST. A peak in the area of 23,194 to 23,226 Da was detected using antibody coupled to the chip. This peak was assigned to correspond to the mass of the IL-6 glycoprotein. Recombinant human IL-6 (rhIL-6) exposed to HD lacked the second disulfide bridge and was partially unfolded, as determined by nuclear magnetic resonance-nuclear Overhauser enhancement and exchange spectroscopy (NMR-NOESY). The disappearance of the resonance peak at 3.54 ppm and the appearance of a new chemical shift at 1.85 ppm suggested that a change in structure had occurred in the presence of HD. From the data, the possibility cannot be excluded that IL-6 might be involved in the early event of structural changes of the signal transducer glycoprotein that indirectly initiates the cascade of events such as skin irritation and blister formation observed in the pathophysiology of HD injury.

Alterations in inflammatory cytokine gene expression in sulfur mustard-exposed mouse skin

Cutaneous exposure to sulfur mustard (bis(2-chloroethyl) sulfide, HD), a chemical warfare agent, produces a delayed inflammatory skin response and severe tissue injury. Despite defined roles of inflammatory cytokines produced or released in response to skin-damaging chemicals, in vivo cytokine responses associated with HD-induced skin pathogenesis are not well understood. Additionally, there is little information on the in vivo temporal sequence of gene expression of cytokines postexposure to HD. The goal of these studies was to identify in vivo molecular biomarkers of HD skin injury within 24 hours after HD challenge. Gene expression of interleukin 1beta (IL-1beta), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin 6 (IL-6), and interleukin 1alpha (IL-1alpha) in the mouse ear vesicant model was examined by quantitative reverse transcription-polymerase chain reaction (RT-PCR). An increase in IL-1beta mRNA levels was first observed at 3 hours. IL-1beta, GM-CSF, and IL-6 mRNA levels were dramatically increased at 6-24 hours postexposure. IL-1alpha mRNA levels were not increased following HD exposure. Immunohistochemical studies demonstrated that IL-1beta and IL-6 protein was produced at multiple sites within the ear, including epithelial cells, inflammatory cells, hair follicles, sebaceous glands, the dermal microvasculature, smooth muscle, and the dermal connective tissue. An increase in the intensity of staining for IL-1beta, and IL-6 was observed in localized areas at 6 hours and was evident in multiple areas at 24 hours. Positive staining for GM-CSF immunoreactive protein was localized to the inflammatory cells within the dermis. The number of immunostaining cells was increased as early as 1 hour following HD exposure. These studies document an early increase in the in vivo expression of inflammatory cytokines following cutaneous HD exposure. An understanding of the in vivo cytokine patterns following HD skin exposure may lead to defining the pathogenic mechanisms of HD injury and the development of pharmacological countermeasures.