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Recent Publications of Rutgers University CounterACT Research Center of Excellence Members

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NCBI: db=pubmed; Term=Laskin JD OR Laskin DL OR Marion MK OR Gerecke DR OR Heindel ND OR Heck DE OR Sinko PJ
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Assessment of mustard vesicant lung injury and anti-TNF-α efficacy in rodents using live-animal imaging.

Wed, 11/11/2020 - 07:32
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Assessment of mustard vesicant lung injury and anti-TNF-α efficacy in rodents using live-animal imaging.

Ann N Y Acad Sci. 2020 Nov 09;:

Authors: Murray A, Gow AJ, Venosa A, Andres J, Malaviya R, Adler D, Yurkow E, Laskin JD, Laskin DL

Abstract
Nitrogen mustard (NM) causes acute lung injury, which progresses to fibrosis. This is associated with a macrophage-dominant inflammatory response and the production of proinflammatory/profibrotic mediators, including tumor necrosis factor alpha (TNF-α). Herein, we refined magnetic resonance imaging (MRI) and computed tomography (CT) imaging methodologies to track the progression of NM-induced lung injury in rodents and assess the efficacy of anti-TNF-α antibody in mitigating toxicity. Anti-TNF-α antibody was administered to rats (15 mg/kg, every 8 days, intravenously) beginning 30 min after treatment with phosphate-buffered saline control or NM (0.125 mg/kg, intratracheally). Animals were imaged by MRI and CT prior to exposure and 1-28 days postexposure. Using MRI, we characterized acute lung injury and fibrosis by quantifying high-signal lung volume, which represents edema, inflammation, and tissue consolidation; these pathologies were found to persist for 28 days following NM exposure. CT scans were used to assess structural components of the lung and to register changes in tissue radiodensities. CT scans showed that in control animals, total lung volume increased with time. Treatment of rats with NM caused loss of lung volume; anti-TNF-α antibody mitigated this decrease. These studies demonstrate that MRI and CT can be used to monitor lung disease and the impact of therapeutic intervention.

PMID: 33165947 [PubMed - as supplied by publisher]

Skin remodeling and wound healing in the Gottingen minipig following exposure to sulfur mustard.

Fri, 10/30/2020 - 10:26
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Skin remodeling and wound healing in the Gottingen minipig following exposure to sulfur mustard.

Exp Mol Pathol. 2020 08;115:104470

Authors: Laskin JD, Wahler G, Croutch CR, Sinko PJ, Laskin DL, Heck DE, Joseph LB

Abstract
Sulfur mustard (SM), a dermal vesicant that has been used in chemical warfare, causes inflammation, edema and epidermal erosions depending on the dose and time following exposure. Herein, a minipig model was used to characterize wound healing following dermal exposure to SM. Saturated SM vapor caps were placed on the dorsal flanks of 3-month-old male Gottingen minipigs for 30 min. After 48 h the control and SM wounded sites were debrided daily for 7 days with wet to wet saline gauze soaks. Animals were then euthanized, and full thickness skin biopsies prepared for histology and immunohistochemistry. Control skin contained a well differentiated epidermis with a prominent stratum corneum. A well-developed eschar covered the skin of SM treated animals, however, the epidermis beneath the eschar displayed significant wound healing with a hyperplastic epidermis. Stratum corneum shedding and a multilayered basal epithelium consisting of cuboidal and columnar cells were also evident in the neoepidermis. Nuclear expression of proliferating cell nuclear antigen (PCNA) was contiguous in cells along the basal epidermal layer of control and SM exposed skin; SM caused a significant increase in PCNA expression in basal and suprabasal cells. SM exposure was also associated with marked changes in expression of markers of wound healing including increases in keratin 10, keratin 17 and loricrin and decreases in E-cadherin. Trichrome staining of control skin showed a well-developed collagen network with no delineation between the papillary and reticular dermis. Conversely, a major delineation was observed in SM-exposed skin including a web-like papillary dermis composed of filamentous extracellular matrix, and compact collagen fibrils in the lower reticular dermis. Although the dermis below the wound site was disrupted, there was substantive epidermal regeneration following SM-induced injury. Further studies analyzing the wound healing process in minipig skin will be important to provide a model to evaluate potential vesicant countermeasures.

PMID: 32445752 [PubMed - indexed for MEDLINE]

Antioxidant/stress response in mouse epidermis following exposure to nitrogen mustard.

Wed, 10/28/2020 - 10:20
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Antioxidant/stress response in mouse epidermis following exposure to nitrogen mustard.

Exp Mol Pathol. 2020 06;114:104410

Authors: Wahler G, Heck DE, Heindel ND, Laskin DL, Laskin JD, Joseph LB

Abstract
Nitrogen mustard (NM) is a highly reactive bifunctional alkylating agent that induces inflammation, edema and blistering in skin. An important mechanism mediating the action of NM and related mustards is oxidative stress. In these studies a modified murine patch-test model was used to analyze DNA damage and the antioxidant/stress response following NM exposure in isolated epidermis. NM (20 μmol) was applied to glass microfiber filters affixed to a shaved dorsal region of skin of CD-1 mice. NM caused structural damage to the stratum corneum as reflected by increases in transepidermal water loss and skin hydration. This was coordinate with edema, mast cell degranulation and epidermal hyperplasia. Within 3 h of NM exposure, a 4-fold increase in phosphorylated histone H2AX, a marker of DNA double-stranded breaks, and a 25-fold increase in phosphorylated p53, a DNA damage marker, were observed in the epidermis. This was associated with a 40% increase in 8-oxo-2'-deoxyguanosine modified DNA in the epidermis and a 4-fold increase in 4-hydroxynonenal modified epidermal proteins. At 12 h post NM, there was a 3-75 fold increase in epidermal expression of antioxidant/stress proteins including heme oxygenase-1, thioredoxin reductase, superoxide dismutase, glutathione reductase, heat shock protein 27 and cyclooxygenase 2. These data indicate that NM induces early oxidative epidermal injury in mouse skin leading to an antioxidant/stress response. Agents that enhance this response may be useful in mitigating mustard-induced skin injury.

PMID: 32113906 [PubMed - indexed for MEDLINE]

NETs: a new biomarker of traffic-related air pollution exposure: are they ready to catch fish?

Wed, 10/21/2020 - 10:53
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NETs: a new biomarker of traffic-related air pollution exposure: are they ready to catch fish?

Eur Respir J. 2020 04;55(4):

Authors: Kipen HM, Laskin DL

PMID: 32245775 [PubMed - indexed for MEDLINE]

Pulmonary toxicants and fibrosis: innate and adaptive immune mechanisms.

Fri, 10/09/2020 - 10:04

Pulmonary toxicants and fibrosis: innate and adaptive immune mechanisms.

Toxicol Appl Pharmacol. 2020 Oct 05;:115272

Authors: Malaviya R, Kipen HM, Businaro R, Laskin JD, Laskin DL

Abstract
Pulmonary fibrosis is characterized by destruction and remodeling of the lung due to an accumulation of collagen and other extracellular matrix components in the tissue. This results in progressive irreversible decreases in lung capacity, impaired gas exchange and eventually, hypoxemia. A number of inhaled and systemic toxicants have been identified that cause pulmonary fibrosis including bleomycin, silica, asbestos, nanoparticles, mustard vesicants, nitrofurantoin, amiodarone, and ionizing radiation. In this article, we review the role of innate and adaptive immune cells and mediators they release in the pathogenesis of fibrotic pathologies induced by pulmonary toxicants. A better understanding of the pathogenic mechanisms underlying fibrogenesis may lead to the development of new therapeutic approaches for patients with these debilitating and largely irreversible chronic diseases.

PMID: 33031836 [PubMed - as supplied by publisher]

Progressive Lung Injury, Inflammation and Fibrosis in Rats following Inhalation of Sulfur Mustard.

Fri, 10/02/2020 - 10:32

Progressive Lung Injury, Inflammation and Fibrosis in Rats following Inhalation of Sulfur Mustard.

Toxicol Sci. 2020 Oct 01;:

Authors: Malaviya R, Abramova EV, Rancourt RC, Sunil VR, Napierala M, Weinstock D, Croutch CR, Roseman J, Tuttle R, Peters E, Casillas RP, Laskin JD, Laskin DL

Abstract
Sulfur mustard (SM) inhalation causes debilitating pulmonary injury in humans which progresses to fibrosis. Herein, we developed a rat model of SM toxicity which parallels pathological changes in the respiratory tract observed in humans. SM vapor inhalation caused dose (0.2 - 0.6 mg/kg) related damage to the respiratory tract within 3 d of exposure. At 0.4 - 0.6 mg/kg, ulceration of the proximal bronchioles, edema and inflammation were observed, along with a proteinaceous exudate containing inflammatory cells in alveolar regions. Time course studies revealed that the pathologic response was biphasic. Thus, changes observed at 3 d post-SM were reduced at 7 d - 16 d; this was followed by more robust aberrations at 28 d, including epithelial necrosis and hyperplasia in the distal bronchioles, thickened alveolar walls, enlarged vacuolated macrophages, and interstitial fibrosis. Histopathologic changes were correlated with biphasic increases in BAL cell and protein content and PCNA expression. Proinflammatory proteins RAGE, HMGB1, and MMP-9 also increased in a biphasic manner following SM inhalation, along with SP-D. TNFα and iNOS, inflammatory proteins implicated in mustard lung toxicity, and the proinflammatory/profibrotic protein, Gal-3, were upregulated in alveolar macrophages and in bronchiolar regions at 3 d and 28 d post-SM. Inflammatory changes in the lung were associated with oxidative stress, as reflected by increased expression of HO-1. These data demonstrate a similar pathologic response to inhaled SM in rats and humans suggesting that this rodent model can be used for mechanistic studies and for the identification of efficacious therapeutics for mitigating toxicity.

PMID: 33002157 [PubMed - as supplied by publisher]

Regulation of Lung Macrophage Activation and Oxidative Stress Following Ozone Exposure by Farnesoid X Receptor.

Tue, 09/29/2020 - 12:20
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Regulation of Lung Macrophage Activation and Oxidative Stress Following Ozone Exposure by Farnesoid X Receptor.

Toxicol Sci. 2020 Sep 10;:

Authors: Francis M, Guo G, Kong B, Abramova EV, Cervelli JA, Gow AJ, Laskin JD, Laskin DL

Abstract
Inflammatory macrophages are known to contribute to ozone toxicity. Farnesoid X receptor (FXR) is a nuclear receptor involved in regulating bile acid and lipid homeostasis; it also exerts anti-inflammatory activity by suppressing macrophage NF-κB. Herein, we analyzed the role of FXR in regulating macrophage activation in the lung following ozone exposure. Treatment of wild-type (WT) mice with ozone (0.8 ppm, 3 h) resulted in increases in proinflammatory (F4/80+CD11c+CD11b+Ly6CHi) and anti-inflammatory (F4/80+CD11c+CD11b+Ly6CLo) macrophages in the lung. The accumulation of proinflammatory macrophages was increased in FXR-/- mice compared with WT mice; however, anti-inflammatory macrophage activation was blunted as reflected by reduced arginase and mannose receptor expression, a response correlated with decreased Nur77. This was associated with prolonged oxidative stress, as measured by 4-hydroxynonenal-modified proteins in the lung. Loss of FXR was accompanied by protracted increases in lung NF-κB activity and its target, inducible nitric oxide synthase in response to ozone. Levels of Tnf-α, Il-1β, Ccr2, Ccl2, Cx3cr1, and Cx3cl1 were also increased in lungs of FXR-/- relative to WT mice; conversely, genes regulating lipid homeostasis including Lxrα, Apoe, Vldlr, Abcg1, and Abca1 were downregulated, irrespective of ozone exposure. In FXR-/- mice, ozone caused an increase in total lung phospholipids, with no effect on SP-B or SP-D. Dyslipidemia was correlated with blunting of ozone-induced increases in positive end-expiratory pressure-dependent quasi-static pressure volume curves indicating a stiffer lung in FXR-/- mice. These findings identify FXR as a regulator of macrophage activation following ozone exposure suggesting that FXR ligands may be useful in mitigating inflammation and oxidative stress induced by pulmonary irritants.

PMID: 32984886 [PubMed - as supplied by publisher]

Phototoxicity of 7-oxycoumarins with keratinocytes in culture.

Wed, 09/23/2020 - 10:59
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Phototoxicity of 7-oxycoumarins with keratinocytes in culture.

Bioorg Chem. 2019 08;89:103014

Authors: Guillon C, Jan YH, Heck DE, Mariano TM, Rapp RD, Jetter M, Kardos K, Whittemore M, Akyea E, Jabin I, Laskin JD, Heindel ND

Abstract
Seventy-one 7-oxycoumarins, 66 synthesized and 5 commercially sourced, were tested for their ability to inhibit growth in murine PAM212 keratinocytes. Forty-nine compounds from the library demonstrated light-induced lethality. None was toxic in the absence of UVA light. Structure-activity correlations indicate that the ability of the compounds to inhibit cell growth was dependent not only on their physiochemical characteristics, but also on their ability to absorb UVA light. Relative lipophilicity was an important factor as was electron density in the pyrone ring. Coumarins with electron withdrawing moieties - cyano and fluoro at C3 - were considerably less active while those with bromines or iodine at that location displayed enhanced activity. Coumarins that were found to inhibit keratinocyte growth were also tested for photo-induced DNA plasmid nicking. A concentration-dependent alteration in migration on neutral gels caused by nicking was observed.

PMID: 31170642 [PubMed - indexed for MEDLINE]

The Amplex Red/horseradish peroxidase assay requires superoxide dismutase to measure hydrogen peroxide in the presence of NAD(P)H.

Sat, 09/12/2020 - 10:48

The Amplex Red/horseradish peroxidase assay requires superoxide dismutase to measure hydrogen peroxide in the presence of NAD(P)H.

Free Radic Res. 2020 Sep 10;:1-32

Authors: Mishin V, Heck DE, Laskin DL, Laskin JD

Abstract
A sensitive fluorescence assay based on Amplex Red (AR) oxidation by horseradish peroxidase (AR/HRP) is described which continuously monitor rates of H2O2 production by microsomal enzymes in the presence of relatively high concentrations of NADPH. NADPH and NADH are known to interact with HRP and generate significant quantities of superoxide anion, a radical that spontaneously dismutates to form H2O2 which interferes with the AR/HRP assay. Microsomal enzymes generate H2O2 as a consequence of electron transfer from NADPH to cytochrome P450 hemoproteins with subsequent oxygen activation. We found that superoxide anion formation via the interaction of NADPH with HRP was inhibited by superoxide dismutase (SOD) without affecting H2O2 generation by microsomal enzymes. Using SOD in enzyme assays, we consistently detected rates of H2O2 production using microgram quantities of microsomal proteins (2.62 ± 0.20 picomol/min/µg protein for liver microsomes from naïve female rats, 12.27 ± 1.29 for liver microsomes from dexamethasone induced male rats, and 2.17 ± 0.25 picomol/min/µg protein for human liver microsomes). This method can also be applied to quantify rates of H2O2 production by oxidases where superoxide anion generation by NADH or NADPH and HRP can interfere with enzyme assays.

PMID: 32912004 [PubMed - as supplied by publisher]

Lung injury, oxidative stress and fibrosis in mice following exposure to nitrogen mustard.

Sat, 08/22/2020 - 10:42
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Lung injury, oxidative stress and fibrosis in mice following exposure to nitrogen mustard.

Toxicol Appl Pharmacol. 2020 01 15;387:114798

Authors: Sunil VR, Vayas KN, Abramova EV, Rancourt R, Cervelli JA, Malaviya R, Goedken M, Venosa A, Gow AJ, Laskin JD, Laskin DL

Abstract
Nitrogen mustard (NM) is a cytotoxic vesicant known to cause acute lung injury which progresses to fibrosis. Herein, we developed a murine model of NM-induced pulmonary toxicity with the goal of assessing inflammatory mechanisms of injury. C57BL/6J mice were euthanized 1-28 d following intratracheal exposure to NM (0.08 mg/kg) or PBS control. NM caused progressive alveolar epithelial thickening, perivascular inflammation, bronchiolar epithelial hyperplasia, interstitial fibroplasia and fibrosis, peaking 14 d post exposure. Enlarged foamy macrophages were also observed in the lung 14 d post NM, along with increased numbers of microparticles in bronchoalveolar lavage fluid (BAL). Following NM exposure, rapid and prolonged increases in BAL cells, protein, total phospholipids and surfactant protein (SP)-D were also detected. Flow cytometric analysis showed that CD11b+Ly6G-F4/80+Ly6Chi proinflammatory macrophages accumulated in the lung after NM, peaking at 3 d. This was associated with macrophage expression of HMGB1 and TNFα in histologic sections. CD11b+Ly6G-F4/80+Ly6Clo anti-inflammatory/pro-fibrotic macrophages also increased in the lung after NM peaking at 14 d, a time coordinate with increases in TGFβ expression and fibrosis. NM exposure also resulted in alterations in pulmonary mechanics including increases in tissue elastance and decreases in compliance and static compliance, most prominently at 14 d. These findings demonstrate that NM induces structural and inflammatory changes in the lung that correlate with aberrations in pulmonary function. This mouse model will be useful for mechanistic studies of mustard lung injury and for assessing potential countermeasures.

PMID: 31678244 [PubMed - indexed for MEDLINE]

Regulation of Macrophage Foam Cell Formation During Nitrogen Mustard (NM)-Induced Pulmonary Fibrosis by Lung Lipids.

Sat, 08/22/2020 - 10:42
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Regulation of Macrophage Foam Cell Formation During Nitrogen Mustard (NM)-Induced Pulmonary Fibrosis by Lung Lipids.

Toxicol Sci. 2019 12 01;172(2):344-358

Authors: Venosa A, Smith LC, Murray A, Banota T, Gow AJ, Laskin JD, Laskin DL

Abstract
Nitrogen mustard (NM) is a vesicant known to target the lung, causing acute injury which progresses to fibrosis. Evidence suggests that activated macrophages contribute to the pathologic response to NM. In these studies, we analyzed the role of lung lipids generated following NM exposure on macrophage activation and phenotype. Treatment of rats with NM (0.125 mg/kg, i.t.) resulted in a time-related increase in enlarged vacuolated macrophages in the lung. At 28 days postexposure, macrophages stained positively for Oil Red O, a marker of neutral lipids. This was correlated with an accumulation of oxidized phospholipids in lung macrophages and epithelial cells and increases in bronchoalveolar lavage fluid (BAL) phospholipids and cholesterol. RNA-sequencing and immunohistochemical analysis revealed that lipid handling pathways under the control of the transcription factors liver-X receptor (LXR), farnesoid-X receptor (FXR), peroxisome proliferator-activated receptor (PPAR)-ɣ, and sterol regulatory element-binding protein (SREBP) were significantly altered following NM exposure. Whereas at 1-3 days post NM, FXR and the downstream oxidized low-density lipoprotein receptor, Cd36, were increased, Lxr and the lipid efflux transporters, Abca1 and Abcg1, were reduced. Treatment of naïve lung macrophages with phospholipid and cholesterol enriched large aggregate fractions of BAL prepared 3 days after NM exposure resulted in upregulation of Nos2 and Ptgs2, markers of proinflammatory activation, whereas large aggregate fractions prepared 28 days post NM upregulated expression of the anti-inflammatory markers, Il10, Cd163, and Cx3cr1, and induced the formation of lipid-laden foamy macrophages. These data suggest that NM-induced alterations in lipid handling and metabolism drive macrophage foam cell formation, potentially contributing to the development of pulmonary fibrosis.

PMID: 31428777 [PubMed - indexed for MEDLINE]

Chemical warfare agent research in precision-cut tissue slices-a useful alternative approach.

Wed, 08/19/2020 - 10:27

Chemical warfare agent research in precision-cut tissue slices-a useful alternative approach.

Ann N Y Acad Sci. 2020 Aug 17;:

Authors: Herbert J, Laskin DL, Gow AJ, Laskin JD

Abstract
The use of chemical warfare agents (CWAs) in military conflicts and against civilians is a recurrent problem. Despite ongoing CWA research using in vitro or in vivo models, progress to elucidate mechanisms of toxicity and to develop effective therapies, decontamination procedures, and general countermeasures is still limited. Novel scientific approaches to address these questions are needed to expand perspectives on existing knowledge and gain new insights. To achieve this, the use of ex vivo techniques like precision-cut tissue slices (PCTSs) can be a valuable approach. Existing studies employing this economical and relatively easy to implement method show model suitability and comparability with the use of in vitro and in vivo models. In this article, we review research on CWAs in PCTSs to illustrate the advantages of the approach and to promote future applications.

PMID: 32808309 [PubMed - as supplied by publisher]

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