35 results on '"Sunil VR"'
Search Results
2. Inflammatory Mediator Expression in the Lung Following Exposure to the Sulfur Mustard Analog, 2-Chloroethyl Ethyl Sulfide; Role of TNFR1.
- Author
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Sunil, VR, primary, Patel, KJ, additional, Malaviya, R, additional, Laskin, JD, additional, and Laskin, DL, additional
- Published
- 2009
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3. Role of macrophage bioenergetics in N-acetylcysteine-mediated mitigation of lung injury and oxidative stress induced by nitrogen mustard.
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Malaviya R, Meshanni JA, Sunil VR, Venosa A, Guo C, Abramova EV, Vayas KN, Jiang C, Cervelli JA, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Animals, Male, Rats, Rats, Sprague-Dawley, Lung drug effects, Lung metabolism, Lung pathology, Macrophages drug effects, Macrophages metabolism, Acute Lung Injury chemically induced, Acute Lung Injury metabolism, Acute Lung Injury pathology, Macrophages, Alveolar drug effects, Macrophages, Alveolar metabolism, Chemical Warfare Agents toxicity, Oxidative Stress drug effects, Acetylcysteine pharmacology, Mechlorethamine toxicity, Energy Metabolism drug effects, Lung Injury chemically induced, Lung Injury metabolism, Lung Injury pathology
- Abstract
Nitrogen mustard (NM) is a toxic vesicant that causes acute injury to the respiratory tract. This is accompanied by an accumulation of activated macrophages in the lung and oxidative stress which have been implicated in tissue injury. In these studies, we analyzed the effects of N-acetylcysteine (NAC), an inhibitor of oxidative stress and inflammation on NM-induced lung injury, macrophage activation and bioenergetics. Treatment of rats with NAC (150 mg/kg, i.p., daily) beginning 30 min after administration of NM (0.125 mg/kg, i.t.) reduced histopathologic alterations in the lung including alveolar interstitial thickening, blood vessel hemorrhage, fibrin deposition, alveolar inflammation, and bronchiolization of alveolar walls within 3 d of exposure; damage to the alveolar-epithelial barrier, measured by bronchoalveolar lavage fluid protein and cells, was also reduced by NAC, along with oxidative stress as measured by heme oxygenase (HO)-1 and Ym-1 expression in the lung. Treatment of rats with NAC attenuated the accumulation of macrophages in the lung expressing proinflammatory genes including Ptgs2, Nos2, Il-6 and Il-12; macrophages expressing inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)α protein were also reduced in histologic sections. Conversely, NAC had no effect on macrophages expressing the anti-inflammatory proteins arginase-1 or mannose receptor, or on NM-induced increases in matrix metalloproteinase (MMP)-9 or proliferating cell nuclear antigen (PCNA), markers of tissue repair. Following NM exposure, lung macrophage basal and maximal glycolytic activity increased, while basal respiration decreased indicating greater reliance on glycolysis to generate ATP. NAC increased both glycolysis and oxidative phosphorylation. Additionally, in macrophages from both control and NM treated animals, NAC treatment resulted in increased S-nitrosylation of ATP synthase, protecting the enzyme from oxidative damage. Taken together, these data suggest that alterations in NM-induced macrophage activation and bioenergetics contribute to the efficacy of NAC in mitigating lung injury., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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4. Single inhalation exposure to polyamide micro and nanoplastic particles impairs vascular dilation without generating pulmonary inflammation in virgin female Sprague Dawley rats.
- Author
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Cary CM, Seymore TN, Singh D, Vayas KN, Goedken MJ, Adams S, Polunas M, Sunil VR, Laskin DL, Demokritou P, and Stapleton PA
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- Humans, Rats, Female, Animals, Rats, Sprague-Dawley, Microplastics, Inhalation Exposure adverse effects, Inhalation Exposure analysis, Dilatation, Respiratory Aerosols and Droplets, Lung, Inflammation chemically induced, Particle Size, Bronchoalveolar Lavage Fluid, Nylons toxicity, Pneumonia chemically induced
- Abstract
Background: Exposure to micro- and nanoplastic particles (MNPs) in humans is being identified in both the indoor and outdoor environment. Detection of these materials in the air has made inhalation exposure to MNPs a major cause for concern. One type of plastic polymer found in indoor and outdoor settings is polyamide, often referred to as nylon. Inhalation of combustion-derived, metallic, and carbonaceous aerosols generate pulmonary inflammation, cardiovascular dysfunction, and systemic inflammation. Additionally, due to the additives present in plastics, MNPs may act as endocrine disruptors. Currently there is limited knowledge on potential health effects caused by polyamide or general MNP inhalation., Objective: The purpose of this study is to assess the toxicological consequences of a single inhalation exposure of female rats to polyamide MNP during estrus by means of aerosolization of MNP., Methods: Bulk polyamide powder (i.e., nylon) served as a representative MNP. Polyamide aerosolization was characterized using particle sizers, cascade impactors, and aerosol samplers. Multiple-Path Particle Dosimetry (MPPD) modeling was used to evaluate pulmonary deposition of MNPs. Pulmonary inflammation was assessed by bronchoalveolar lavage (BAL) cell content and H&E-stained tissue sections. Mean arterial pressure (MAP), wire myography of the aorta and uterine artery, and pressure myography of the radial artery was used to assess cardiovascular function. Systemic inflammation and endocrine disruption were quantified by measurement of proinflammatory cytokines and reproductive hormones., Results: Our aerosolization exposure platform was found to generate particles within the micro- and nano-size ranges (thereby constituting MNPs). Inhaled particles were predicted to deposit in all regions of the lung; no overt pulmonary inflammation was observed. Conversely, increased blood pressure and impaired dilation in the uterine vasculature was noted while aortic vascular reactivity was unaffected. Inhalation of MNPs resulted in systemic inflammation as measured by increased plasma levels of IL-6. Decreased levels of 17β-estradiol were also observed suggesting that MNPs have endocrine disrupting activity., Conclusions: These data demonstrate aerosolization of MNPs in our inhalation exposure platform. Inhaled MNP aerosols were found to alter inflammatory, cardiovascular, and endocrine activity. These novel findings will contribute to a better understanding of inhaled plastic particle toxicity., (© 2023. The Author(s).)
- Published
- 2023
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5. Impaired energy metabolism and altered functional activity of alveolar type II epithelial cells following exposure of rats to nitrogen mustard.
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Sunil VR, Vayas KN, Radbel J, Abramova E, Gow A, Laskin JD, and Laskin DL
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- Rats, Male, Animals, Rats, Wistar, Alveolar Epithelial Cells, Oxidative Stress, Energy Metabolism, Surface-Active Agents adverse effects, Mechlorethamine toxicity, Acute Lung Injury chemically induced
- Abstract
Nitrogen mustard (NM) is a cytotoxic vesicant known to cause acute lung injury which progresses to fibrosis. Alveolar Type II cells are primarily responsible for surfactant production; they also play a key role in lung repair following injury. Herein, we assessed the effects of NM on Type II cell activity. Male Wistar rats were administered NM (0.125 mg/kg) or PBS control intratracheally. Type II cells, lung tissue and BAL were collected 3 d later. NM exposure resulted in double strand DNA breaks in Type II cells, as assessed by expression of γH2AX; this was associated with decreased expression of the DNA repair protein, PARP1. Expression of HO-1 was upregulated and nitrotyrosine residues were noted in Type II cells after NM exposure indicating oxidative stress. NM also caused alterations in Type II cell energy metabolism; thus, both glycolysis and oxidative phosphorylation were reduced; there was also a shift from a reliance on oxidative phosphorylation to glycolysis for ATP production. This was associated with increased expression of pro-apoptotic proteins activated caspase-3 and -9, and decreases in survival proteins, β-catenin, Nur77, HMGB1 and SOCS2. Intracellular signaling molecules important in Type II cell activity including PI3K, Akt2, phospho-p38 MAPK and phospho-ERK were reduced after NM exposure. This was correlated with dysregulation of surfactant protein production and impaired pulmonary functioning. These data demonstrate that Type II cells are targets of NM-induced DNA damage and oxidative stress. Impaired functioning of these cells may contribute to pulmonary toxicity caused by mustards., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Debra Laskin reports financial support was provided by National Institutes of Health. She is an Associate Editor of Toxicology and Applied Pharmacology, (Copyright © 2022 Elsevier Inc. All rights reserved.)
- Published
- 2022
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6. Microvesicle-Derived miRNAs Regulate Proinflammatory Macrophage Activation in the Lung Following Ozone Exposure.
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Carnino JM, Lee H, Smith LC, Sunil VR, Rancourt RC, Vayas K, Cervelli J, Kwok ZH, Ni K, Laskin JD, Jin Y, and Laskin DL
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- Animals, Lung metabolism, Macrophage Activation, Mice, RNA, Messenger metabolism, MicroRNAs genetics, MicroRNAs metabolism, Ozone toxicity
- Abstract
Ozone is a ubiquitous air pollutant that causes lung damage and altered functioning. Evidence suggests that proinflammatory macrophages contribute to ozone toxicity. Herein, we analyzed the role of extracellular vesicles (EVs) and microRNA (miRNA) cargo in ozone-induced macrophage activation. Exposure of mice to ozone (0.8 ppm, 3 h) resulted in increases in bronchoalveolar lavage fluid EVs, which were comprised predominantly of microvesicles (MVs). NanoFACS analysis revealed that MVs generated following both air and ozone exposure was largely from CD45+ myeloid cells; these MVs were readily taken up by macrophages. Functionally, MVs from ozone, but not air treated mice, upregulated mRNA expression of inflammatory proteins in macrophages including inducible nitric oxide synthase (iNOS), CXCL-1, CXCL-2, and interleukin (IL)-1β. The miRNA profile of MVs in bronchoalveolar lavage fluid (BALF) was altered after ozone exposure; thus, increases in miR-21, miR-145, miR320a, miR-155, let-7b, miR744, miR181, miR-17, miR-92a, and miR-199a-3p were observed, whereas miR-24-3p and miR-20 were reduced. Ingenuity pathway analysis revealed that these miRNAs regulate pathways that promote inflammatory macrophage activation, and predicted that let-7a-5p/let-7b, miR-24-3p, miR-21-5p, miR-17, and miR-181a-5p are key upstream regulators of inflammatory proteins. After ozone exposure, miR-199a-3p, but not precursor miR-199a-3p, was increased in lung macrophages, indicating that it is derived from MV-mediated delivery. Furthermore, lung macrophage mRNA expression of IL-1β was upregulated after administration of MVs containing miR-199a-3p mimic but downregulated by miR-199a-3p inhibitor. Collectively, these data suggest that MVs generated following ozone exposure contribute to proinflammatory macrophage activation via MV-derived miRNAs including miR-199a-3p. These findings identify a novel pathway regulating macrophage inflammatory responses to inhaled ozone., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2022
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7. Pulmonary injury and oxidative stress in rats induced by inhaled sulfur mustard is ameliorated by anti-tumor necrosis factor-α antibody.
- Author
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Malaviya R, Bellomo A, Abramova E, Croutch CR, Roseman J, Tuttle R, Peters E, Casillas RP, Sunil VR, Laskin JD, and Laskin DL
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- Acute Lung Injury metabolism, Animals, Antibodies, Monoclonal pharmacology, Chemical Warfare Agents toxicity, Inhalation Exposure adverse effects, Male, Mustard Gas administration & dosage, Oxidative Stress physiology, Rats, Rats, Wistar, Tumor Necrosis Factor-alpha metabolism, Acute Lung Injury chemically induced, Acute Lung Injury drug therapy, Antibodies, Monoclonal therapeutic use, Mustard Gas toxicity, Oxidative Stress drug effects, Tumor Necrosis Factor-alpha antagonists & inhibitors
- Abstract
Sulfur mustard (SM) is a bifunctional alkylating agent that causes severe injury to the respiratory tract. This is accompanied by an accumulation of macrophages in the lung and the release of the proinflammatory cytokine, tumor necrosis factor (TNF)α. In these studies, we analyzed the effects of blocking TNFα on lung injury, inflammation and oxidative stress induced by inhaled SM. Rats were treated with SM vapor (0.4 mg/kg) or air control by intratracheal inhalation. This was followed 15-30 min later by anti-TNFα antibody (15mg/kg, i.v.) or PBS control. Animals were euthanized 3 days later. Anti-TNFα antibody was found to blunt SM-induced peribronchial edema, perivascular inflammation and alveolar plasma protein and inflammatory cell accumulation in the lung; this was associated with reduced expression of PCNA in histologic sections and decreases in BAL levels of fibrinogen. SM-induced increases in inflammatory proteins including soluble receptor for glycation end products, its ligand, high mobility group box-1, and matrix metalloproteinase-9 were also reduced by anti-TNFα antibody administration, along with increases in numbers of lung macrophages expressing TNFα, cyclooxygenase-2 and inducible nitric oxide synthase. This was correlated with reduced oxidative stress as measured by expression of heme oxygenase-1 and Ym-1. Together, these data suggest that inhibiting TNFα may represent an efficacious approach to mitigating acute lung injury, inflammatory macrophage activation, and oxidative stress induced by inhaled sulfur mustard., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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8. Progressive Lung Injury, Inflammation, and Fibrosis in Rats Following Inhalation of Sulfur Mustard.
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Malaviya R, Abramova EV, Rancourt RC, Sunil VR, Napierala M, Weinstock D, Croutch CR, Roseman J, Tuttle R, Peters E, Casillas RP, Laskin JD, and Laskin DL
- Subjects
- Animals, Fibrosis, Inflammation pathology, Lung drug effects, Oxidative Stress, Rats, Chemical Warfare Agents toxicity, Lung Injury pathology, Mustard Gas toxicity
- 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 days 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 days post-SM were reduced at 7-16 days; this was followed by more robust aberrations at 28 days, 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 bronchoalveolar lavage (BAL) cell and protein content and proliferating cell nuclear antigen expression. Proinflammatory proteins receptor for advanced glycation end product (RAGE), high-mobility group box protein (HMGB)-1, and matrix metalloproteinase (MMP)-9 also increased in a biphasic manner following SM inhalation, along with surfactant protein-D (SP-D). Tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS), inflammatory proteins implicated in mustard lung toxicity, and the proinflammatory/profibrotic protein, galectin (Gal)-3, were upregulated in alveolar macrophages and in bronchiolar regions at 3 and 28 days post-SM. Inflammatory changes in the lung were associated with oxidative stress, as reflected by increased expression of heme oxygenase (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., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2020
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9. Lung injury, oxidative stress and fibrosis in mice following exposure to nitrogen mustard.
- Author
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Sunil VR, Vayas KN, Abramova EV, Rancourt R, Cervelli JA, Malaviya R, Goedken M, Venosa A, Gow AJ, Laskin JD, and Laskin DL
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- Acute Lung Injury immunology, Acute Lung Injury pathology, Animals, Disease Models, Animal, Feasibility Studies, Female, Fibrosis, Humans, Lung drug effects, Macrophages drug effects, Macrophages immunology, Male, Mice, Oxidative Stress drug effects, Acute Lung Injury chemically induced, Chemical Warfare Agents toxicity, Lung pathology, Mechlorethamine toxicity
- 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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Inc.)- Published
- 2020
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10. Sarcoid-Like Granulomatous Disease: Pathologic Case Series in World Trade Center Dust Exposed Rescue and Recovery Workers.
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Sunil VR, Radbel J, Hussain S, Vayas KN, Cervelli J, Deen M, Kipen H, Udasin I, Laumbach R, Sunderram J, Laskin JD, and Laskin DL
- Subjects
- Adult, Dust, Female, Humans, Male, Middle Aged, Occupational Exposure, Sarcoidosis etiology, September 11 Terrorist Attacks
- Abstract
Sarcoid-like granulomatous diseases (SGD) have been previously identified in cohorts of World Trade Center (WTC) dust-exposed individuals. In the present studies, we analyzed lung and/or lymph node biopsies from patients referred to our clinic with suspected WTC dust-induced lung disease to evaluate potential pathophysiologic mechanisms. Histologic sections of lung and/or lymph node samples were analyzed for markers of injury, oxidative stress, inflammation, fibrosis, and epigenetic modifications. Out of seven patients examined, we diagnosed four with SGD and two with pulmonary fibrosis; one was diagnosed later with SGD at another medical facility. Patients with SGD were predominantly white, obese men, who were less than 50 years old and never smoked. Cytochrome b5, cytokeratin 17, heme oxygenase-1, lipocalin-2, inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor α, ADP-ribosylation factor-like GTPase 11, mannose receptor-1, galectin-3, transforming growth factor β, histone-3 and methylated histone-3 were identified in lung and lymph nodes at varying levels in all samples examined. Three of the biopsy samples with granulomas displayed peri-granulomatous fibrosis. These findings are important and suggest the potential of WTC dust-induced fibrotic sarcoid. It is likely that patient demographics and/or genetic factors influence the response to WTC dust injury and that these contribute to different pathological outcomes.
- Published
- 2019
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11. Protective Role of Surfactant Protein-D Against Lung Injury and Oxidative Stress Induced by Nitrogen Mustard.
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Sunil VR, Vayas KN, Cervelli JA, Ebramova EV, Gow AJ, Goedken M, Malaviya R, Laskin JD, and Laskin DL
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- Animals, Bronchoalveolar Lavage Fluid cytology, Female, Lung Injury metabolism, Lung Injury pathology, Macrophage Activation drug effects, Macrophages, Alveolar metabolism, Macrophages, Alveolar pathology, Male, Mice, Mice, Inbred C57BL, Lung Injury chemically induced, Macrophages, Alveolar drug effects, Mechlorethamine toxicity, Oxidative Stress drug effects, Pulmonary Surfactant-Associated Protein D metabolism
- Abstract
Nitrogen mustard (NM) is a vesicant known to cause acute pulmonary injury which progresses to fibrosis. Macrophages contribute to both of these pathologies. Surfactant protein (SP)-D is a pulmonary collectin that suppresses lung macrophage activity. Herein, we analyzed the effects of loss of SP-D on NM-induced macrophage activation and lung toxicity. Wild-type (WT) and SP-D-/- mice were treated intratracheally with PBS or NM (0.08 mg/kg). Bronchoalveolar lavage (BAL) fluid and tissue were collected 14 days later. In WT mice, NM caused an increase in total SP-D levels in BAL; multiple lower molecular weight forms of SP-D were also identified, consistent with lung injury and oxidative stress. Flow cytometric analysis of BAL cells from NM treated WT mice revealed the presence of proinflammatory and anti-inflammatory macrophages. Whereas loss of SP-D had no effect on numbers of these cells, their activation state, as measured by proinflammatory (iNOS, MMP-9), and anti-inflammatory (MR-1, Ym-1) protein expression, was amplified. Loss of SP-D also exacerbated NM-induced oxidative stress and alveolar epithelial injury, as reflected by increases in heme oxygenase-1 expression, and BAL cell and protein content. This was correlated with alterations in pulmonary mechanics. In NM-treated SP-D-/-, but not WT mice, there was evidence of edema, epithelial hypertrophy and hyperplasia, bronchiectasis, and fibrosis, as well as increases in BAL phospholipid content. These data demonstrate that activated lung macrophages play a role in NM-induced lung injury and oxidative stress. Elucidating mechanisms regulating macrophage activity may be important in developing therapeutics to treat mustard-induced lung injury.
- Published
- 2018
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12. World Trade Center (WTC) dust exposure in mice is associated with inflammation, oxidative stress and epigenetic changes in the lung.
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Sunil VR, Vayas KN, Fang M, Zarbl H, Massa C, Gow AJ, Cervelli JA, Kipen H, Laumbach RJ, Lioy PJ, Laskin JD, and Laskin DL
- Subjects
- Animals, Blotting, Western, Cyclooxygenase 2 metabolism, Cytokines genetics, DNA Methylation drug effects, Female, Gene Expression drug effects, Heme Oxygenase-1 metabolism, Histones metabolism, Humans, Immunohistochemistry, Inflammation etiology, Inflammation genetics, Inhalation Exposure, Lung drug effects, Lung metabolism, Lung physiopathology, Lysine metabolism, Matrix Metalloproteinases metabolism, Methylation drug effects, Mice, Inbred C57BL, Reverse Transcriptase Polymerase Chain Reaction, September 11 Terrorist Attacks, Up-Regulation drug effects, Air Pollutants toxicity, Dust, Epigenesis, Genetic, Inflammation diagnosis, Oxidative Stress
- Abstract
Exposure to World Trade Center (WTC) dust has been linked to respiratory disease in humans. In the present studies we developed a rodent model of WTC dust exposure to analyze lung oxidative stress and inflammation, with the goal of elucidating potential epigenetic mechanisms underlying these responses. Exposure of mice to WTC dust (20μg, i.t.) was associated with upregulation of heme oxygenase-1 and cyclooxygenase-2 within 3days, a response which persisted for at least 21days. Whereas matrix metalloproteinase was upregulated 7days post-WTC dust exposure, IL-6RA1 was increased at 21days; conversely, expression of mannose receptor, a scavenger receptor important in particle clearance, decreased. After WTC dust exposure, increases in methylation of histone H3 lysine K4 at 3days, lysine K27 at 7days and lysine K36, were observed in the lung, along with hypermethylation of Line-1 element at 21days. Alterations in pulmonary mechanics were also observed following WTC dust exposure. Thus, 3days post-exposure, lung resistance and tissue damping were decreased. In contrast at 21days, lung resistance, central airway resistance, tissue damping and tissue elastance were increased. These data demonstrate that WTC dust-induced inflammation and oxidative stress are associated with epigenetic modifications in the lung and altered pulmonary mechanics. These changes may contribute to the development of WTC dust pathologies., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2017
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13. Mustard vesicant-induced lung injury: Advances in therapy.
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Weinberger B, Malaviya R, Sunil VR, Venosa A, Heck DE, Laskin JD, and Laskin DL
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- Animals, Fibrin metabolism, Humans, Lung drug effects, Lung metabolism, Lung Injury metabolism, Matrix Metalloproteinases metabolism, Mesenchymal Stem Cells, RNA, Untranslated, Reactive Nitrogen Species metabolism, Reactive Oxygen Species metabolism, Transforming Growth Factor beta metabolism, Transient Receptor Potential Channels metabolism, Tumor Necrosis Factor-alpha metabolism, Chemical Warfare Agents toxicity, Irritants toxicity, Lung Injury chemically induced, Lung Injury therapy, Mustard Gas toxicity
- Abstract
Most mortality and morbidity following exposure to vesicants such as sulfur mustard is due to pulmonary toxicity. Acute injury is characterized by epithelial detachment and necrosis in the pharynx, trachea and bronchioles, while long-term consequences include fibrosis and, in some instances, cancer. Current therapies to treat mustard poisoning are primarily palliative and do not target underlying pathophysiologic mechanisms. New knowledge about vesicant-induced pulmonary disease pathogenesis has led to the identification of potentially efficacious strategies to reduce injury by targeting inflammatory cells and mediators including reactive oxygen and nitrogen species, proteases and proinflammatory/cytotoxic cytokines. Therapeutics under investigation include corticosteroids, N-acetyl cysteine, which has both mucolytic and antioxidant properties, inducible nitric oxide synthase inhibitors, liposomes containing superoxide dismutase, catalase, and/or tocopherols, protease inhibitors, and cytokine antagonists such as anti-tumor necrosis factor (TNF)-α antibody and pentoxifylline. Antifibrotic and fibrinolytic treatments may also prove beneficial in ameliorating airway obstruction and lung remodeling. More speculative approaches include inhibitors of transient receptor potential channels, which regulate pulmonary epithelial cell membrane permeability, non-coding RNAs and mesenchymal stem cells. As mustards represent high priority chemical threat agents, identification of effective therapeutics for mitigating toxicity is highly significant., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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14. Inflammatory mechanisms of pulmonary injury induced by mustards.
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Malaviya R, Sunil VR, Venosa A, Vayas KN, Heck DE, Laskin JD, and Laskin DL
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- Animals, Antidotes therapeutic use, Disease Models, Animal, Humans, Inflammation Mediators metabolism, Inhalation Exposure, Lung metabolism, Lung pathology, Lung physiopathology, Lung Injury drug therapy, Lung Injury metabolism, Lung Injury pathology, Lung Injury physiopathology, Macrophages, Alveolar drug effects, Macrophages, Alveolar metabolism, Pneumonia drug therapy, Pneumonia metabolism, Pneumonia pathology, Pneumonia physiopathology, Signal Transduction drug effects, Lung drug effects, Lung Injury chemically induced, Nitrogen Mustard Compounds toxicity, Pneumonia chemically induced
- Abstract
Exposure of humans and animals to vesicants, including sulfur mustard (SM) and nitrogen mustard (NM), causes severe and debilitating damage to the respiratory tract. Both acute and long term pathological consequences are observed in the lung following a single exposure to these vesicants. Evidence from our laboratories and others suggest that macrophages and the inflammatory mediators they release play an important role in mustard-induced lung injury. In this paper, the pathogenic effects of SM and NM on the lung are reviewed, along with the potential role of inflammatory macrophages and mediators they release in mustard-induced pulmonary toxicity., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
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15. Attenuation of Nitrogen Mustard-Induced Pulmonary Injury and Fibrosis by Anti-Tumor Necrosis Factor-α Antibody.
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Malaviya R, Sunil VR, Venosa A, Verissimo VL, Cervelli JA, Vayas KN, Hall L, Laskin JD, and Laskin DL
- Subjects
- Alkylating Agents chemistry, Animals, Antibodies, Monoclonal genetics, Antibodies, Monoclonal metabolism, Biomarkers metabolism, Chemical Warfare Agents chemistry, Chemical Warfare Agents toxicity, Disease Progression, Immunoglobulin G genetics, Immunoglobulin G metabolism, Immunoglobulin G therapeutic use, Lung immunology, Lung pathology, Macrophages drug effects, Macrophages immunology, Macrophages metabolism, Macrophages pathology, Male, Mechlorethamine antagonists & inhibitors, Mice, Molecular Targeted Therapy, Oxidative Stress drug effects, Pulmonary Emphysema chemically induced, Pulmonary Emphysema pathology, Pulmonary Emphysema physiopathology, Pulmonary Fibrosis etiology, Pulmonary Fibrosis immunology, Rats, Wistar, Recombinant Proteins metabolism, Recombinant Proteins therapeutic use, Respiratory Mucosa drug effects, Respiratory Mucosa immunology, Respiratory Mucosa pathology, Tumor Necrosis Factor-alpha metabolism, Alkylating Agents toxicity, Antibodies, Monoclonal therapeutic use, Lung drug effects, Mechlorethamine toxicity, Pulmonary Emphysema drug therapy, Pulmonary Fibrosis prevention & control, Tumor Necrosis Factor-alpha antagonists & inhibitors
- Abstract
Nitrogen mustard (NM) is a bifunctional alkylating agent that causes acute injury to the lung that progresses to fibrosis. This is accompanied by a prominent infiltration of macrophages into the lung and upregulation of proinflammatory/profibrotic cytokines including tumor necrosis factor (TNF)α. In these studies, we analyzed the ability of anti-TNFα antibody to mitigate NM-induced lung injury, inflammation, and fibrosis. Treatment of rats with anti-TNFα antibody (15 mg/kg, iv, every 9 days) beginning 30 min after intratracheal administration of NM (0.125 mg/kg) reduced progressive histopathologic alterations in the lung including perivascular and peribronchial edema, macrophage/monocyte infiltration, interstitial thickening, bronchiolization of alveolar walls, fibrin deposition, emphysema, and fibrosis. NM-induced damage to the alveolar-epithelial barrier, measured by bronchoalveolar lavage (BAL) protein and cell content, was also reduced by anti-TNFα antibody, along with expression of the oxidative stress marker, heme oxygenase-1. Whereas the accumulation of proinflammatory/cytotoxic M1 macrophages in the lung in response to NM was suppressed by anti-TNFα antibody, anti-inflammatory/profibrotic M2 macrophages were increased or unchanged. Treatment of rats with anti-TNFα antibody also reduced NM-induced increases in expression of the profibrotic mediator, transforming growth factor-β. This was associated with a reduction in NM-induced collagen deposition in the lung. These data suggest that inhibiting TNFα may represent an efficacious approach to mitigating lung injury induced by mustards., (© The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2015
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16. Regulation of ozone-induced lung inflammation and injury by the β-galactoside-binding lectin galectin-3.
- Author
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Sunil VR, Francis M, Vayas KN, Cervelli JA, Choi H, Laskin JD, and Laskin DL
- Subjects
- Animals, Female, Galactosides metabolism, Lung drug effects, Lung metabolism, Macrophages, Alveolar drug effects, Macrophages, Alveolar metabolism, Mice, Mice, Inbred C57BL, Nitric Oxide Synthase Type II metabolism, Galectin 3 metabolism, Galectins metabolism, Lung Injury chemically induced, Lung Injury metabolism, Ozone toxicity, Pneumonia chemically induced, Pneumonia metabolism
- Abstract
Macrophages play a dual role in ozone toxicity, contributing to both pro- and anti-inflammatory processes. Galectin-3 (Gal-3) is a lectin known to regulate macrophage activity. Herein, we analyzed the role of Gal-3 in the response of lung macrophages to ozone. Bronchoalveolar lavage (BAL) and lung tissue were collected 24-72h after exposure (3h) of WT and Gal-3(-/-) mice to air or 0.8ppm ozone. In WT mice, ozone inhalation resulted in increased numbers of proinflammatory (Gal-3(+), iNOS(+)) and anti-inflammatory (MR-1(+)) macrophages in the lungs. While accumulation of iNOS(+) macrophages was attenuated in Gal-3(-/-) mice, increased numbers of enlarged MR-1(+) macrophages were noted. This correlated with increased numbers of macrophages in BAL. Flow cytometric analysis showed that these cells were CD11b(+) and consisted mainly (>97%) of mature (F4/80(+)CD11c(+)) proinflammatory (Ly6GLy6C(hi)) and anti-inflammatory (Ly6GLy6C(lo)) macrophages. Increases in both macrophage subpopulations were observed following ozone inhalation. Loss of Gal-3 resulted in a decrease in Ly6C(hi) macrophages, with no effect on Ly6C(lo) macrophages. CD11b(+)Ly6G(+)Ly6C(+) granulocytic (G) and monocytic (M) myeloid derived suppressor cells (MDSC) were also identified in the lung after ozone. In Gal-3(-/-) mice, the response of G-MDSC to ozone was attenuated, while the response of M-MDSC was heightened. Changes in inflammatory cell populations in the lung of ozone treated Gal-3(-/-) mice were correlated with reduced tissue injury as measured by cytochrome b5 expression. These data demonstrate that Gal-3 plays a role in promoting proinflammatory macrophage accumulation and toxicity in the lung following ozone exposure., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
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17. Pentoxifylline attenuates nitrogen mustard-induced acute lung injury, oxidative stress and inflammation.
- Author
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Sunil VR, Vayas KN, Cervelli JA, Malaviya R, Hall L, Massa CB, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Acute Lung Injury chemically induced, Acute Lung Injury drug therapy, Animals, Chemical Warfare Agents toxicity, Cyclooxygenase 2 metabolism, Heme Oxygenase-1 metabolism, Irritants toxicity, Lipocalin-2, Lipocalins metabolism, Macrophages, Alveolar drug effects, Macrophages, Alveolar metabolism, Male, Matrix Metalloproteinase 9 metabolism, Pneumonia drug therapy, Rats, Rats, Wistar, Receptors, CXCR3 metabolism, Acute Lung Injury pathology, Mechlorethamine toxicity, Oxidative Stress drug effects, Pentoxifylline pharmacology, Pneumonia chemically induced
- Abstract
Nitrogen mustard (NM) is a toxic alkylating agent that causes damage to the respiratory tract. Evidence suggests that macrophages and inflammatory mediators including tumor necrosis factor (TNF)α contribute to pulmonary injury. Pentoxifylline is a TNFα inhibitor known to suppress inflammation. In these studies, we analyzed the ability of pentoxifylline to mitigate NM-induced lung injury and inflammation. Exposure of male Wistar rats (150-174 g; 8-10 weeks) to NM (0.125 mg/kg, i.t.) resulted in severe histopathological changes in the lung within 3d of exposure, along with increases in bronchoalveolar lavage (BAL) cell number and protein, indicating inflammation and alveolar-epithelial barrier dysfunction. This was associated with increases in oxidative stress proteins including lipocalin (Lcn)2 and heme oxygenase (HO)-1 in the lung, along with pro-inflammatory/cytotoxic (COX-2(+) and MMP-9(+)), and anti-inflammatory/wound repair (CD163+ and Gal-3(+)) macrophages. Treatment of rats with pentoxifylline (46.7 mg/kg, i.p.) daily for 3d beginning 15 min after NM significantly reduced NM-induced lung injury, inflammation, and oxidative stress, as measured histologically and by decreases in BAL cell and protein content, and levels of HO-1 and Lcn2. Macrophages expressing COX-2 and MMP-9 also decreased after pentoxifylline, while CD163+ and Gal-3(+) macrophages increased. This was correlated with persistent upregulation of markers of wound repair including pro-surfactant protein-C and proliferating nuclear cell antigen by Type II cells. NM-induced lung injury and inflammation were associated with alterations in the elastic properties of the lung, however these were largely unaltered by pentoxifylline. These data suggest that pentoxifylline may be useful in treating acute lung injury, inflammation and oxidative stress induced by vesicants., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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18. Ozone-induced injury and oxidative stress in bronchiolar epithelium are associated with altered pulmonary mechanics.
- Author
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Sunil VR, Vayas KN, Massa CB, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Acute Lung Injury metabolism, Acute Lung Injury physiopathology, Animals, Bronchioles drug effects, Bronchioles metabolism, Disease Models, Animal, Female, Lung metabolism, Lung physiopathology, Rats, Rats, Wistar, Respiratory Function Tests, Respiratory Mucosa metabolism, Acute Lung Injury chemically induced, Lung drug effects, Oxidative Stress drug effects, Ozone toxicity, Respiratory Mucosa drug effects
- Abstract
In these studies, we analyzed the effects of ozone on bronchiolar epithelium. Exposure of rats to ozone (2 ppm, 3 h) resulted in rapid (within 3 h) and persistent (up to 72 h) histological changes in the bronchiolar epithelium, including hypercellularity, loss of cilia, and necrotizing bronchiolitis. Perivascular edema and vascular congestion were also evident, along with a decrease in Clara cell secretory protein in bronchoalveolar lavage, which was maximal 24 h post-exposure. Ozone also induced the appearance of 8-hydroxy-2'-deoxyguanosine, Ym1, and heme oxygenase-1 in the bronchiolar epithelium. This was associated with increased expression of cleaved caspase-9 and beclin-1, indicating initiation of apoptosis and autophagy. A rapid and persistent increase in galectin-3, a regulator of epithelial cell apoptosis, was also observed. Following ozone exposure (3-24 h), increased expression of cyclooxygenase-2, inducible nitric oxide synthase, and arginase-1 was noted in bronchiolar epithelium. Ozone-induced injury and oxidative stress in bronchiolar epithelium were linked to methacholine-induced alterations in pulmonary mechanics. Thus, significant increases in lung resistance and elastance, along with decreases in lung compliance and end tidal volume, were observed at higher doses of methacholine. This indicates that ozone causes an increase in effective stiffness of the lung as a consequence of changes in the conducting airways. Collectively, these studies demonstrate that bronchiolar epithelium is highly susceptible to injury and oxidative stress induced by acute exposure to ozone; moreover, this is accompanied by altered lung functioning.
- Published
- 2013
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19. Biodistribution and renal clearance of biocompatible lung targeted poly(ethylene glycol) (PEG) nanogel aggregates.
- Author
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Deshmukh M, Kutscher HL, Gao D, Sunil VR, Malaviya R, Vayas K, Stein S, Laskin JD, Laskin DL, and Sinko PJ
- Subjects
- Animals, Biocompatible Materials chemistry, Drug Carriers chemistry, Drug Compounding, Drug Delivery Systems, Drug Stability, Injections, Intravenous, Lung metabolism, Male, Metabolic Clearance Rate, Microscopy, Electron, Transmission, Nanogels, Particle Size, Polyethylene Glycols chemistry, Polyethyleneimine chemistry, Rats, Rats, Sprague-Dawley, Surface Properties, Tissue Distribution, Biocompatible Materials pharmacokinetics, Drug Carriers pharmacokinetics, Kidney metabolism, Lung drug effects, Polyethylene Glycols pharmacokinetics, Polyethyleneimine pharmacokinetics
- Abstract
A novel stabilized aggregated nanogel particle (SANP) drug delivery system was prepared for injectable passive lung targeting. Gel nanoparticles (GNPs) were synthesized by irreversibly cross-linking 8 Arm PEG thiol with 1,6-hexane-bis-vinylsulfone (HBVS) in phosphate buffer (PB, pH 7.4) containing 0.1% v/v Tween™ 80. Aggregated nanogel particles (ANPs) were generated by aggregating GNPs to micron-size, which were then stabilized (i.e., SANPs) using a PEG thiol polymer to prevent further growth-aggregation. The size of SANPs, ANPs and GNPs was analyzed using a Coulter counter and transmission electron microscopy (TEM). Stability studies of SANPs were performed at 37°C in rat plasma, phosphate buffered saline (PBS, pH 7.4) and PB (pH 7.4). SANPs were stable in rat plasma, PBS and PB over 7 days. SANPs were covalently labeled with HiLyte Fluor™ 750 (DYE-SANPs) to facilitate ex vivo imaging. Biodistribution of intravenous DYE-SANPs (30 μm, 4 mg in 500 μL PBS) in male Sprague-Dawley rats was compared to free HiLyte Fluor™ 750 DYE alone (1mg in 500 μL PBS) and determined using a Xenogen IVIS® 100 Imaging System. Biodistribution studies demonstrated that free DYE was rapidly eliminated from the body by renal filtration, whereas DYE-SANPs accumulated in the lung within 30 min and persisted for 48 h. DYE-SANPs were enzymatically degraded to their original principle components (i.e., DYE-PEG-thiol and PEG-VS polymer) and were then eliminated from the body by renal filtration. Histological evaluation using H & E staining and broncho alveolar lavage (BAL) confirmed that these flexible SANPs were not toxic. This suggests that because of their flexible and non-toxic nature, SANPs may be a useful alternative for treating pulmonary diseases such as asthma, pneumonia, tuberculosis and disseminated lung cancer., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
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20. Classical and alternative macrophage activation in the lung following ozone-induced oxidative stress.
- Author
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Sunil VR, Patel-Vayas K, Shen J, Laskin JD, and Laskin DL
- Subjects
- 8-Hydroxy-2'-Deoxyguanosine, Animals, Apoptosis drug effects, Autophagy drug effects, Cell Proliferation drug effects, Deoxyguanosine analogs & derivatives, Deoxyguanosine genetics, Female, Heme Oxygenase-1 genetics, Inflammation chemically induced, Inflammation pathology, Lung pathology, Macrophages, Alveolar pathology, Ozone administration & dosage, Ozone toxicity, Protein C genetics, Rats, Rats, Wistar, Time Factors, Gene Expression Regulation drug effects, Lung drug effects, Macrophages, Alveolar drug effects, Oxidative Stress drug effects
- Abstract
Ozone is a pulmonary irritant known to cause oxidative stress, inflammation and tissue injury. Evidence suggests that macrophages play a role in the pathogenic response; however, their contribution depends on the mediators they encounter in the lung which dictate their function. In these studies we analyzed the effects of ozone-induced oxidative stress on the phenotype of alveolar macrophages (AM). Exposure of rats to ozone (2 ppm, 3h) resulted in increased expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), as well as heme oxygenase-1 (HO-1) in AM. Whereas 8-OHdG was maximum at 24h, expression of HO-1 was biphasic increasing after 3h and 48-72 h. Cleaved caspase-9 and beclin-1, markers of apoptosis and autophagy, were also induced in AM 24h post-ozone. This was associated with increased bronchoalveolar lavage protein and cells, as well as matrix metalloproteinase (MMP)-2 and MMP-9, demonstrating alveolar epithelial injury. Ozone intoxication resulted in biphasic activation of the transcription factor, NFκB. This correlated with expression of monocyte chemotactic protein-1, inducible nitric oxide synthase and cyclooxygenase-2, markers of proinflammatory macrophages. Increases in arginase-1, Ym1 and galectin-3 positive anti-inflammatory/wound repair macrophages were also observed in the lung after ozone inhalation, beginning at 24h (arginase-1, Ym1), and persisting for 72 h (galectin-3). This was associated with increased expression of pro-surfactant protein-C, a marker of Type II cell proliferation and activation, important steps in wound repair. These data suggest that both proinflammatory/cytotoxic and anti-inflammatory/wound repair macrophages are activated early in the response to ozone-induced oxidative stress and tissue injury., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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21. Role of reactive nitrogen species generated via inducible nitric oxide synthase in vesicant-induced lung injury, inflammation and altered lung functioning.
- Author
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Sunil VR, Shen J, Patel-Vayas K, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Acute-Phase Proteins genetics, Animals, Chemical Warfare Agents toxicity, Female, Gene Expression Regulation drug effects, Inflammation chemically induced, Lipocalin-2, Lipocalins genetics, Lung drug effects, Lung physiopathology, Lung Injury chemically induced, Mice, Mice, Inbred C57BL, Mice, Knockout, Mustard Gas toxicity, Nitric Oxide Synthase Type II genetics, Oncogene Proteins genetics, Oxidative Stress drug effects, Time Factors, Tumor Necrosis Factor-alpha genetics, Inflammation physiopathology, Lung Injury physiopathology, Mustard Gas analogs & derivatives, Nitric Oxide Synthase Type II metabolism, Reactive Nitrogen Species metabolism
- Abstract
Pulmonary toxicity induced by sulfur mustard and related vesicants is associated with oxidative stress. In the present studies we analyzed the role of reactive nitrogen species (RNS) generated via inducible nitric oxide synthase (iNOS) in lung injury and inflammation induced by vesicants using 2-chloroethyl ethyl sulfide (CEES) as a model. C57Bl/6 (WT) and iNOS-/- mice were sacrificed 3 days or 14 days following intratracheal administration of CEES (6 mg/kg) or control. CEES intoxication resulted in transient (3 days) increases in bronchoalveolar lavage (BAL) cell and protein content in WT, but not iNOS-/- mice. This correlated with expression of Ym1, a marker of oxidative stress in alveolar macrophages and epithelial cells. In contrast, in iNOS-/- mice, Ym1 was only observed 14 days post-exposure in enlarged alveolar macrophages, suggesting that they are alternatively activated. This is supported by findings that lung tumor necrosis factor and lipocalin Lcn2 expression, mediators involved in tissue repair were also upregulated at this time in iNOS-/- mice. Conversely, CEES-induced increases in the proinflammatory genes, monocyte chemotactic protein-1 and cyclooxygenase-2, were abrogated in iNOS-/- mice. In WT mice, CEES treatment also resulted in increases in total lung resistance and decreases in compliance in response to methacholine, effects blunted by loss of iNOS. These data demonstrate that RNS, generated via iNOS play a role in the pathogenic responses to CEES, augmenting oxidative stress and inflammation and suppressing tissue repair. Elucidating inflammatory mechanisms mediating vesicant-induced lung injury is key to the development of therapeutics to treat mustard poisoning., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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22. Role of TNFR1 in lung injury and altered lung function induced by the model sulfur mustard vesicant, 2-chloroethyl ethyl sulfide.
- Author
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Sunil VR, Patel-Vayas K, Shen J, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Animals, Bronchoalveolar Lavage Fluid chemistry, Lung physiopathology, Lung Injury metabolism, Lung Injury physiopathology, Male, Mice, Mice, Knockout, Mustard Gas toxicity, Oxidative Stress drug effects, Receptors, Tumor Necrosis Factor, Type I genetics, Tumor Necrosis Factor-alpha physiology, Irritants toxicity, Lung drug effects, Lung Injury chemically induced, Mustard Gas analogs & derivatives, Receptors, Tumor Necrosis Factor, Type I metabolism
- Abstract
Lung toxicity induced by sulfur mustard is associated with inflammation and oxidative stress. To elucidate mechanisms mediating pulmonary damage, we used 2-chloroethyl ethyl sulfide (CEES), a model sulfur mustard vesicant. Male mice (B6129) were treated intratracheally with CEES (3 or 6 mg/kg) or control. Animals were sacrificed 3, 7 or 14 days later and bronchoalveolar lavage (BAL) fluid and lung tissue collected. Treatment of mice with CEES resulted in an increase in BAL protein, an indication of alveolar epithelial damage, within 3 days. Expression of Ym1, an oxidative stress marker also increased in the lung, along with inducible nitric oxide synthase, and at 14 days, cyclooxygenase-2 and monocyte chemotactic protein-1, inflammatory proteins implicated in tissue injury. These responses were attenuated in mice lacking the p55 receptor for TNFα (TNFR1-/-), demonstrating that signaling via TNFR1 is key to CEES-induced injury, oxidative stress, and inflammation. CEES-induced upregulation of CuZn-superoxide dismutase (SOD) and MnSOD was delayed or absent in TNFR1-/- mice, relative to WT mice, suggesting that TNFα mediates early antioxidant responses to lung toxicants. Treatment of WT mice with CEES also resulted in functional alterations in the lung including decreases in compliance and increases in elastance. Additionally, methacholine-induced alterations in total lung resistance and central airway resistance were dampened by CEES. Loss of TNFR1 resulted in blunted functional responses to CEES. These effects were most notable in the airways. These data suggest that targeting TNFα signaling may be useful in mitigating lung injury, inflammation and functional alterations induced by vesicants., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2011
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23. Sulfur mustard-induced pulmonary injury: therapeutic approaches to mitigating toxicity.
- Author
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Weinberger B, Laskin JD, Sunil VR, Sinko PJ, Heck DE, and Laskin DL
- Subjects
- Animals, Anti-Inflammatory Agents therapeutic use, Antioxidants therapeutic use, Humans, Models, Animal, Protease Inhibitors therapeutic use, Pulmonary Surfactants therapeutic use, Lung drug effects, Mustard Gas toxicity
- Abstract
Sulfur mustard (SM) is highly toxic to the lung inducing both acute and chronic effects including upper and lower obstructive disease, airway inflammation, and acute respiratory distress syndrome, and with time, tracheobronchial stenosis, bronchitis, and bronchiolitis obliterans. Thus it is essential to identify effective strategies to mitigate the toxicity of SM and related vesicants. Studies in animals and in cell culture models have identified key mechanistic pathways mediating their toxicity, which may be relevant targets for the development of countermeasures. For example, following SM poisoning, DNA damage, apoptosis, and autophagy are observed in the lung, along with increased expression of activated caspases and DNA repair enzymes, biochemical markers of these activities. This is associated with inflammatory cell accumulation in the respiratory tract and increased expression of tumor necrosis factor-α and other proinflammatory cytokines, as well as reactive oxygen and nitrogen species. Matrix metalloproteinases are also upregulated in the lung after SM exposure, which are thought to contribute to the detachment of epithelial cells from basement membranes and disruption of the pulmonary epithelial barrier. Findings that production of inflammatory mediators correlates directly with altered lung function suggests that they play a key role in toxicity. In this regard, specific therapeutic interventions currently under investigation include anti-inflammatory agents (e.g., steroids), antioxidants (e.g., tocopherols, melatonin, N-acetylcysteine, nitric oxide synthase inhibitors), protease inhibitors (e.g., doxycycline, aprotinin, ilomastat), surfactant replacement, and bronchodilators. Effective treatments may depend on the extent of lung injury and require a multi-faceted pharmacological approach., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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24. Macrophages and tissue injury: agents of defense or destruction?
- Author
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Laskin DL, Sunil VR, Gardner CR, and Laskin JD
- Subjects
- Animals, Fibrosis physiopathology, Humans, Inflammation etiology, Inflammation physiopathology, Macrophages drug effects, Neoplasms physiopathology, Wound Healing physiology, Inflammation Mediators metabolism, Macrophages metabolism, Xenobiotics toxicity
- Abstract
The past several years have seen the accumulation of evidence demonstrating that tissue injury induced by diverse toxicants is due not only to their direct effects on target tissues but also indirectly to the actions of resident and infiltrating macrophages. These cells release an array of mediators with cytotoxic, pro- and anti-inflammatory, angiogenic, fibrogenic, and mitogenic activity, which function to fight infections, limit tissue injury, and promote wound healing. However, following exposure to toxicants, macrophages can become hyperresponsive, resulting in uncontrolled or dysregulated release of mediators that exacerbate acute tissue injury and/or promote the development of chronic diseases such as fibrosis and cancer. Evidence suggests that the diverse activity of macrophages is mediated by distinct subpopulations that develop in response to signals within their microenvironment. Understanding the precise roles of these different macrophage populations in the pathogenic response to toxicants is key to designing effective treatments for minimizing tissue damage and chronic disease and for facilitating wound repair.
- Published
- 2011
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25. Functional and inflammatory alterations in the lung following exposure of rats to nitrogen mustard.
- Author
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Sunil VR, Patel KJ, Shen J, Reimer D, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Animals, Cyclooxygenase 2 metabolism, Lung metabolism, Lung pathology, Male, Nitric Oxide Synthase Type II metabolism, Rats, Inflammation Mediators metabolism, Irritants toxicity, Lung drug effects, Mechlorethamine toxicity
- Abstract
Nitrogen mustard is a vesicant that causes damage to the respiratory tract. In these studies, we characterized the acute effects of nitrogen mustard on lung structure, inflammatory mediator expression, and pulmonary function, with the goal of identifying mediators potentially involved in toxicity. Treatment of rats (male Wistar, 200-225 g) with nitrogen mustard (mechlorethamine hydrochloride, i.t., 0.25mg/kg) resulted in marked histological changes in the respiratory tract, including necrotizing bronchiolitis, thickening of alveolar septa, and inflammation which was evident within 24h. This was associated with increases in bronchoalveolar lavage protein and cells, confirming injury to alveolar epithelial regions of the lung. Nitrogen mustard administration also resulted in increased expression of inducible nitric oxide synthase and cyclooxygenase-2, pro-inflammatory proteins implicated in lung injury, in alveolar macrophages and alveolar and bronchial epithelial cells. Expression of connective tissue growth factor and matrix metalloproteinase-9, mediators regulating extracellular matrix turnover was also increased, suggesting that pathways leading to chronic lung disease are initiated early in the pathogenic process. Following nitrogen mustard exposure, alterations in lung mechanics and function were also observed. These included decreases in baseline static compliance, end-tidal volume and airway resistance, and a pronounced loss of methacholine responsiveness in resistance, tissue damping and elastance. Taken together, these data demonstrate that nitrogen mustard induces rapid structural and inflammatory changes in the lung which are associated with altered lung functioning. Understanding the nature of the injury induced by nitrogen mustard and related analogs may aid in the development of efficacious therapies for treatment of pulmonary injury resulting from exposure to vesicants., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2011
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26. Inflammatory effects of inhaled sulfur mustard in rat lung.
- Author
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Malaviya R, Sunil VR, Cervelli J, Anderson DR, Holmes WW, Conti ML, Gordon RE, Laskin JD, and Laskin DL
- Subjects
- Animals, Antioxidants metabolism, Apoptosis, Autophagy, Bronchoalveolar Lavage Fluid, Chemical Warfare Agents, Lung enzymology, Lung metabolism, Male, Nitric Oxide Synthase Type II metabolism, Pneumonia enzymology, Pneumonia metabolism, Rats, Rats, Sprague-Dawley, Tumor Necrosis Factor-alpha metabolism, Lung drug effects, Mustard Gas toxicity, Pneumonia chemically induced
- Abstract
Inhalation of sulfur mustard (SM), a bifunctional alkylating agent that causes severe lung damage, is a significant threat to both military and civilian populations. The mechanisms mediating its cytotoxic effects are unknown and were investigated in the present studies. Male rats Crl:CD(SD) were anesthetized, and then intratracheally intubated and exposed to 0.7-1.4mg/kg SM by vapor inhalation. Animals were euthanized 6, 24, 48h or 7days post-exposure and bronchoalveolar lavage fluid (BAL) and lung tissue collected. Exposure of rats to SM resulted in rapid pulmonary toxicity, including focal ulceration and detachment of the trachea and bronchial epithelia from underlying mucosa, thickening of alveolar septal walls and increased numbers of inflammatory cells in the tissue. There was also evidence of autophagy and apoptosis in the tissue. This was correlated with increased BAL protein content, a marker of injury to the alveolar epithelial lining. SM exposure also resulted in increased expression of markers of inflammation including cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNFα), inducible nitric oxide synthase (iNOS), and matrix metalloproteinase-9 (MMP-9), each of which has been implicated in pulmonary toxicity. Whereas COX-2, TNFα and iNOS were mainly localized in alveolar regions, MMP-9 was prominent in bronchial epithelium. In contrast, expression of the anti-oxidant hemeoxygenase, and the anti-inflammatory collectin, surfactant protein-D, decreased in the lung after SM exposure. These data demonstrate that SM-induced oxidative stress and injury are associated with the generation of cytotoxic inflammatory proteins which may contribute to the pathogenic response to this vesicant., (Copyright © 2010. Published by Elsevier Inc.)
- Published
- 2010
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27. Pulmonary effects of inhaled diesel exhaust in young and old mice: a pilot project.
- Author
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Laskin DL, Mainelis G, Turpin BJ, Patel KJ, and Sunil VR
- Subjects
- Administration, Inhalation, Age Factors, Animals, Biomarkers analysis, Bronchoalveolar Lavage Fluid cytology, Disease Models, Animal, Dose-Response Relationship, Drug, Immunohistochemistry, Inflammation Mediators metabolism, Lung metabolism, Lung pathology, Lung Diseases metabolism, Lung Diseases pathology, Male, Mice, Neutrophils, Particle Size, Particulate Matter analysis, Pilot Projects, Reverse Transcriptase Polymerase Chain Reaction, Tumor Necrosis Factor-alpha metabolism, Vehicle Emissions analysis, Lung drug effects, Lung Diseases chemically induced, Particulate Matter toxicity, Vehicle Emissions toxicity
- Abstract
It is well established that exposure to ambient fine particulate matter (PM), defined as PM < or = 2.5 microm in aerodynamic diameter (PM2.5), is associated with increased cardiovascular morbidity and mortality and that elderly persons are particularly susceptible to these effects. We speculated that the increased susceptibility of elderly persons to PM is due to altered production of inflammatory mediators and antioxidants in the lung. We performed pilot studies in an animal model to test this hypothesis. For these studies we used diesel exhaust (DE), a major component of urban PM, as a model. Two groups of male CB6F1 mice, 2 months and 18 months old, (referred to in this report as young and old mice, respectively) were exposed to DE at 300 or 1000 microg/m3 PM (referred to as low- or high-dose DE, respectively), or to filtered air as a control, for one 3-hour period (single exposure) or for 3 hours on each of three consecutive days (repeated exposure). Mice were killed and bronchoalveolar lavage (BAL) fluid, serum, and lung tissue were collected immediately after exposure (0 hours) and 24 hours after the final exposure. After single or repeated exposure to DE, persistent structural alterations and inflammation were observed in the lungs of old mice. These changes consisted of patchy thickening of alveolar septa and an increase in the number of neutrophils and macrophages in alveolar spaces. In the young mice, in contrast, no major alterations in lung histology were noted. In old but not in young mice, significant increases in messenger RNA (mRNA) expression of the oxidative-stress marker lipocalin 24p3 were also observed. In both young and old mice, exposure to DE was associated with increased expression of tumor necrosis factor alpha (TNF-alpha) mRNA in the lung. However, this response was attenuated in old mice. Exposure to high-dose DE resulted in significant increases in interleukin (IL)-6 and IL-8 mRNA expression in the lungs of old animals; these increases persisted for 24 hours. Whereas IL-6 was also up-regulated in young mice after DE exposure, no major effects were evident on the expression of IL-8 mRNA. Expression of the antioxidant enzyme manganese superoxide dismutase (MnSOD) was decreased in lung tissue from young animals after single or repeated exposure to DE. In contrast, constitutive expression of MnSOD was not evident in lungs of old mice, and DE had no effect on the expression of this antioxidant. These preliminary data confirm that old mice are more sensitive to DE than young mice and that increased sensitivity is associated with altered expression of inflammatory cytokines and the antioxidant MnSOD. These aberrations may contribute to the increased susceptibility of old mice to inhaled PM.
- Published
- 2010
28. Macrophages, reactive nitrogen species, and lung injury.
- Author
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Laskin DL, Sunil VR, Fakhrzadeh L, Groves A, Gow AJ, and Laskin JD
- Subjects
- Animals, Caveolin 1 antagonists & inhibitors, Caveolin 1 biosynthesis, Caveolin 1 physiology, Humans, Lung Injury pathology, Macrophages pathology, Reactive Nitrogen Species physiology, Signal Transduction immunology, Tumor Necrosis Factor-alpha metabolism, Tumor Necrosis Factor-alpha physiology, Lung Injury immunology, Lung Injury metabolism, Macrophages immunology, Macrophages metabolism, Reactive Nitrogen Species metabolism
- Abstract
Evidence has accumulated over the past several years demonstrating that lung injury following inhalation of irritants like ozone is due, not only to direct effects of the chemical, but also indirectly to the actions of inflammatory mediators released by infiltrating macrophages. Among the mediators involved in the cytotoxic process, reactive nitrogen species (RNS) are of particular interest because of their well-documented cytotoxic potential. Findings that macrophage suppression blocks RNS production and ozone-induced toxicity provide strong support for a role of these cells and inflammatory mediators in lung injury. Recent investigations have focused on understanding pathways by which macrophages become activated to release RNS. One protein that has attracted considerable attention is caveolin-1, a membrane scaffolding molecule that functions to negatively regulate cell signaling. The fact that expression of caveolin-1 is down-regulated in macrophages after ozone inhalation suggests a mechanism controlling the release of cytotoxic mediators by these inflammatory cells.
- Published
- 2010
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29. Pulmonary effects of inhaled diesel exhaust in aged mice.
- Author
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Sunil VR, Patel KJ, Mainelis G, Turpin BJ, Ridgely S, Laumbach RJ, Kipen HM, Nazarenko Y, Veleeparambil M, Gow AJ, Laskin JD, and Laskin DL
- Subjects
- Aerosols, Animals, Antioxidants metabolism, Bronchoalveolar Lavage Fluid cytology, Immunohistochemistry, Inflammation Mediators metabolism, L-Lactate Dehydrogenase metabolism, Lung drug effects, Lung metabolism, Lung pathology, Lung Diseases metabolism, Lung Diseases pathology, Male, Mice, Nitrogen Oxides metabolism, Oxidative Stress drug effects, Particle Size, Particulate Matter analysis, Particulate Matter toxicity, Reverse Transcriptase Polymerase Chain Reaction, Superoxide Dismutase metabolism, Tumor Necrosis Factor-alpha metabolism, Aging physiology, Lung Diseases chemically induced, Vehicle Emissions toxicity
- Abstract
Pulmonary morbidity and mortality resulting from exposure to fine particulate matter (PM) increases with age. The present studies analyzed potential mechanisms underlying increased susceptibility of the elderly to PM using diesel exhaust (DE) as a model. Mice (2 m and 18 m) were exposed to DE (0, 300, and 1000 microg/m(3)) for 3 h once (single) or 3 h/day for 3 days (repeated). Bronchoalveolar lavage fluid (BAL), serum and lung tissue were collected 0 and 24 h later. Exposure to DE resulted in structural alterations in the lungs of older but not younger mice, including patchy thickening of the alveolar septa and inflammatory cell localization in alveolar spaces. These effects were most pronounced 24 h after a single exposure to the higher dose of DE. Significant increases in BAL nitrogen oxides were also noted in older mice, as well as expression of lipocalin 24p3, an oxidative stress marker in the lung with no effects in younger mice. Following DE inhalation, expression of Tumor Necrosis Factor alpha (TNFalpha) was upregulated in lungs of both younger and older mice; however, this was attenuated in older animals. Whereas exposure to DE resulted in increases in lung Interleukin-6 (IL-6) expression in both older and younger mice, IL-8 increased only in older animals. In younger mice, constitutive expression of manganese superoxide dismutase (MnSOD) decreased after DE exposure, while in older mice, constitutive MnSOD was not detectable and DE had no effect on expression of this antioxidant. Taken together, these results suggest that altered generation of inflammatory mediators and MnSOD may contribute to increased susceptibility of older mice to inhaled DE.
- Published
- 2009
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30. Acute endotoxemia is associated with upregulation of lipocalin 24p3/Lcn2 in lung and liver.
- Author
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Sunil VR, Patel KJ, Nilsen-Hamilton M, Heck DE, Laskin JD, and Laskin DL
- Subjects
- Animals, Endotoxemia genetics, Female, Gene Expression Regulation drug effects, Lipocalin-2, Lipocalins, Lipopolysaccharides pharmacology, Liver physiopathology, Lung physiopathology, Macrophages, Alveolar pathology, Macrophages, Alveolar physiology, Mice, Rats, Rats, Sprague-Dawley, Acute-Phase Proteins genetics, Carrier Proteins genetics, Endotoxemia pathology, Liver pathology, Lung pathology, Oncogene Proteins genetics
- Abstract
Acute endotoxemia is associated with production of acute phase proteins which regulate inflammatory responses to tissue injury. Consistent with DNA microarray experiments, we found that acute endotoxemia, induced by administration of lipopolysaccharide (LPS) to mice (1 mg/kg) or rats (5 mg/kg), resulted in increased expression of the hepatic acute phase protein, lipocalin 24p3, which was evident within 4 h and persisted for 24-48 h. Increases in 24p3 expression were also observed in the lung after LPS administration, as well as in isolated liver and lung macrophages, and Type II alveolar epithelial cells. The actions of LPS are dependent, in part, on Toll-like receptor (TLR) proteins. Macrophages from C3H/HeJ mice, which possess a nonfunctional TLR-4, expressed low levels of 24p3 mRNA when compared to cells from control C3H/OuJ mice. Whereas LPS administration increased 24p3 expression in lung and liver macrophages from control C3H/OuJ mice, minimal effects were observed in TLR-4 mutant mice demonstrating that TLR-4 is important in regulating 24p3 expression during acute endotoxemia. Promoters for genes encoding lipocalin proteins including 24p3 contain consensus sequences for transcription factors including NF-kappaB, and C/EBP. Acute endotoxemia resulted in NF-kappaB nuclear binding activity in both alveolar macrophages and Type II cells. In contrast, C/EBP activation was evident only in Type II cells, suggesting differential effects of LPS on these cell types. These data suggest that the acute phase response to acute endotoxemia involves induction of 24p3 in both the lung and liver. This protein may be important in restoring tissue homeostasis following LPS-induced injury.
- Published
- 2007
- Full Text
- View/download PDF
31. Pulmonary effects of inhaled limonene ozone reaction products in elderly rats.
- Author
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Sunil VR, Laumbach RJ, Patel KJ, Turpin BJ, Lim HJ, Kipen HM, Laskin JD, and Laskin DL
- Subjects
- Administration, Inhalation, Aerosols, Animals, Antioxidants metabolism, Blotting, Western, Bronchoalveolar Lavage Fluid chemistry, Bronchoalveolar Lavage Fluid cytology, Cell Count, Cyclohexenes administration & dosage, Cyclohexenes chemistry, Electrophoretic Mobility Shift Assay, Female, Inflammation Mediators metabolism, Limonene, Macrophages, Alveolar cytology, Macrophages, Alveolar drug effects, Macrophages, Alveolar metabolism, Mitogen-Activated Protein Kinases metabolism, Models, Theoretical, Ozone administration & dosage, Ozone chemistry, Protein Binding drug effects, Pulmonary Alveoli cytology, Pulmonary Alveoli metabolism, Rats, Rats, Inbred F344, Specific Pathogen-Free Organisms, Superoxide Dismutase metabolism, Terpenes administration & dosage, Terpenes chemistry, Transcription Factors metabolism, Aging, Cyclohexenes toxicity, Ozone toxicity, Pulmonary Alveoli drug effects, Terpenes toxicity
- Abstract
d-Limonene is an unsaturated volatile organic chemical found in cleaning products, air fresheners and soaps. It is oxidized by ozone to secondary organic aerosols consisting of aldehydes, acids, oxidants and fine and ultra fine particles. The lung irritant effects of these limonene ozone reaction products (LOP) were investigated. Female F344 rats (2- and 18-month-old) were exposed for 3 h to air or LOP formed by reacting 6 ppm d-limonene and 0.8 ppm ozone. BAL fluid, lung tissue and cells were analyzed 0 h and 20 h later. Inhalation of LOP increased TNF-alpha, cyclooxygenase-2, and superoxide dismutase in alveolar macrophages (AM) and Type II cells. Responses of older animals were attenuated when compared to younger animals. LOP also decreased p38 MAP kinase in AM from both younger and older animals. In contrast, while LOP increased p44/42 MAP kinase in AM from younger rats, expression decreased in AM and Type II cells from older animals. NF-kappaB and C/EBP activity also increased in AM from younger animals following LOP exposure but decreased or was unaffected in Type II cells. Whereas in younger animals LOP caused endothelial cell hypertrophy, perivascular and pleural edema and thickening of alveolar septal walls, in lungs from older animals, patchy accumulation of fluid within septal walls in alveolar sacs and subtle pleural edema were noted. LOP are pulmonary irritants inducing distinct inflammatory responses in younger and older animals. This may contribute to the differential sensitivity of these populations to pulmonary irritants.
- Published
- 2007
- Full Text
- View/download PDF
32. Activation of type II alveolar epithelial cells during acute endotoxemia.
- Author
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Sunil VR, Connor AJ, Guo Y, Laskin JD, and Laskin DL
- Subjects
- Acute Disease, Animals, Cyclooxygenase 2, DNA-Binding Proteins metabolism, Endotoxemia immunology, Epithelial Cells enzymology, Epithelial Cells immunology, Female, Interferon Regulatory Factor-1, Isoenzymes metabolism, Macrophages, Alveolar immunology, NF-kappa B antagonists & inhibitors, NF-kappa B metabolism, Nitric Oxide metabolism, Nitric Oxide Synthase metabolism, Nitric Oxide Synthase Type II, Phosphoproteins metabolism, Prostaglandin-Endoperoxide Synthases metabolism, Protein Binding physiology, Pulmonary Alveoli cytology, Pulmonary Alveoli immunology, Rats, Rats, Sprague-Dawley, Respiratory Mucosa cytology, Respiratory Mucosa immunology, Specific Pathogen-Free Organisms, Endotoxemia metabolism, Pulmonary Alveoli enzymology, Respiratory Mucosa enzymology
- Abstract
Lung injury induced by acute endotoxemia is associated with increased generation of inflammatory mediators such as nitric oxide and eicosanoids, which have been implicated in the pathophysiological process. Although production of these mediators by alveolar macrophages (AM) has been characterized, the response of type II cells is unknown and was assessed in the present studies. Acute endotoxemia caused a rapid (within 1 h) and prolonged (up to 48 h) induction of nitric oxide synthase-2 (NOS-2) in type II cells but a delayed response in AM (12-24 h). In both cell types, this was associated with increased nitric oxide production. Although type II cells, and to a lesser extent AM, constitutively expressed cyclooxygenase-2, acute endotoxemia did not alter this activity. Endotoxin administration had no effect on mitogen-activated protein kinase or protein kinase B-alpha (PKB-alpha) expression. However, increases in phosphoinositide 3-kinase and phospho-PKB-alpha were observed in type II cells. The finding that this was delayed for 12-24 h suggests that these proteins do not play a significant role in the regulation of NOS-2 in this model. After endotoxin administration to rats, a rapid (within 1-2 h) activation of nuclear factor-kappaB was observed. This response was transient in type II cells but was sustained in AM. Interferon regulatory factor-1 (IRF-1) was also activated rapidly in type II cells. In contrast, IRF-1 activation was delayed in AM. These data demonstrate that type II cells, like AM, are highly responsive during acute endotoxemia and may contribute to pulmonary inflammation.
- Published
- 2002
- Full Text
- View/download PDF
33. Acute endotoxemia prolongs the survival of rat lung neutrophils in response to 12-O-tetradecanoyl-phorbol 13-acetate.
- Author
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Sunil VR, Connor AJ, Lavnikova N, Gardner CR, Laskin JD, and Laskin DL
- Subjects
- Acute Disease, Animals, Apoptosis drug effects, CCAAT-Enhancer-Binding Proteins antagonists & inhibitors, CCAAT-Enhancer-Binding Proteins metabolism, Cell Nucleus metabolism, Cell Survival drug effects, Cell Survival physiology, Endotoxemia pathology, Female, Interferon-gamma pharmacology, Mitogen-Activated Protein Kinases metabolism, NF-kappa B antagonists & inhibitors, NF-kappa B metabolism, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins metabolism, Proto-Oncogene Proteins c-akt, Rats, Rats, Sprague-Dawley, Endotoxemia physiopathology, Neutrophils physiology, Protein Serine-Threonine Kinases, Pulmonary Circulation, Tetradecanoylphorbol Acetate pharmacology
- Abstract
Acute endotoxemia is associated with prolonged survival of adherent neutrophils in the lung vasculature. In the present studies, the effects of inflammatory mediators on signaling pathways regulating neutrophil survival were examined. We found that the protein kinase C activator, 12-O-tetradecanoyl-phorbol 13-acetate (TPA), but not interferon-gamma (IFN-gamma), prolonged the survival of adherent vasculature lung neutrophils from endotoxemic rats, a response that was correlated with reduced apoptosis. Although endotoxin administration to rats induced the expression of the anti-apoptotic protein Mcl-1 in lung neutrophils, TPA had no effect on this response. Endotoxin administration also induced expression of total p38 and p44/42 mitogen activated protein kinases (MAPK) in neutrophils, as well as phosphatidyl inositol 3 kinase (PI3K) and its downstream target protein kinase B (PKB). Treatment of the cells with TPA increased p38 MAPK expression in cells from both control and endotoxin treated animals. Cells from endotoxin treated, but not control animals, were found to exhibit constitutive binding activity of nuclear factor kappa B (NF-kappaB) which was blocked by TPA. In contrast, constitutive CCAAT/enhancer binding protein (C/EBP) nuclear binding activity evident in neutrophils from control animals was reduced following endotoxin administration. Moreover, this response was independent of TPA. These data suggest that NF-kappaB plays a role in TPA-induced signaling leading to prolonged survival of adherent vascular neutrophils in the lung during acute endotoxemia., (Copyright 2002 Wiley‐Liss, Inc.)
- Published
- 2002
- Full Text
- View/download PDF
34. Activation of adherent vascular neutrophils in the lung during acute endotoxemia.
- Author
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Sunil VR, Connor AJ, Zhou P, Gordon MK, Laskin JD, and Laskin DL
- Subjects
- Acute Disease, Animals, Cell Adhesion physiology, Cell Survival physiology, Female, Lung metabolism, Rats, Rats, Sprague-Dawley, Endotoxemia metabolism, Endotoxemia pathology, Endotoxins pharmacology, Lung blood supply, Lung pathology, Neutrophil Activation physiology, Neutrophils metabolism, Neutrophils pathology
- Abstract
Background: Neutrophils constitute the first line of defense against invading microorganisms. Whereas these cells readily undergo apoptosis under homeostatic conditions, their survival is prolonged during inflammatory reactions and they become biochemically and functionally activated. In the present study, we analyzed the effects of acute endotoxemia on the response of a unique subpopulation of neutrophils tightly adhered to the lung vasculature., Methods: Rats were treated with 5 mg/kg lipopolysaccharide (i.v.) to induce acute endotoxemia. Adherent neutrophils were isolated from the lung vasculature by collagenase digestion and sequential filtering. Agarose gel electrophoresis, RT-PCR, western blotting and electrophoretic mobility shift assays were used to evaluate neutrophil activity., Results: Adherent vascular neutrophils isolated from endotoxemic animals exhibited decreased apoptosis when compared to cells from control animals. This was associated with a marked increase in expression of the anti-apoptotic protein, Mcl-1. Cells isolated 0.5-2 hours after endotoxin administration were more chemotactic than cells from control animals and expressed increased tumor necrosis factor-alpha and cyclooxygenase-2 mRNA and protein, demonstrating that they are functionally activated. Endotoxin treatment of the animals also induced p38 and p44/42 mitogen activated protein kinases in the adherent lung neutrophils, as well as nuclear binding activity of the transcription factors, NF-kappaB and cAMP response element binding protein., Conclusion: These data demonstrate that adherent vascular lung neutrophils are highly responsive to endotoxin and that pathways regulating apoptosis and cellular activation are upregulated in these cells.
- Published
- 2002
- Full Text
- View/download PDF
35. Mechanisms underlying reduced responsiveness of neonatal neutrophils to distinct chemoattractants.
- Author
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Weinberger B, Laskin DL, Mariano TM, Sunil VR, DeCoste CJ, Heck DE, Gardner CR, and Laskin JD
- Subjects
- Adult, Antibodies, Monoclonal, Calcium physiology, Fetal Blood, Humans, Infant, Newborn, N-Formylmethionine Leucyl-Phenylalanine, Neutrophils cytology, Signal Transduction, Chemotactic Factors, Chemotaxis, Leukocyte physiology, Neutrophils physiology
- Abstract
Potential mechanisms underlying impaired chemotactic responsiveness of neonatal neutrophils were investigated. Two distinct chemoattractants were compared: bacterially derived N-formyl-methionyl-leucyl-phenylalanine (fMLP) and a unique chemotactic monoclonal antibody, designated DL1.2, which binds to a neutrophil antigen with an apparent molecular mass of 120 kDa. Chemotaxis of neutrophils toward fMLP, as well as DL1.2, was reduced in neonates when compared with adult cells. This did not appear to be a result of decreased fMLP receptor or DL1.2 antigen expression by neonatal neutrophils. fMLP, but not DL1.2, induced a rapid increase in intracellular calcium in adult and neonatal cells, which reached a maximum within 30 s. The calcium response of cells from neonates to fMLP was reduced when compared with adult cells, and an unresponsive subpopulation of neonatal neutrophils was identified. NF-kappaB nuclear binding activity induced by fMLP and DL1.2, as well as expression of the p65 NF-kappaB subunit and IkappaB-alpha, was also significantly reduced in neonatal cells, when compared with adult cells. In contrast, although fMLP, but not DL1.2, activated p42/44 and p38 mitogen-activated protein (MAP) kinases in neutrophils, no differences were observed between adults and neonates. Chemotaxis of adult and neonatal neutrophils toward fMLP and DL1.2 was also blocked to a similar extent by inhibitors of phosphatidylinositol 3-kinase, as well as an inhibitor of NF-kappaB. These findings indicate that reduced chemotactic responsiveness in neonatal neutrophils is a result of, at least in part, aberrations in chemoattractant-induced signaling. However, the biochemical pathways mediating this defect appear to be related to the specific chemoattractant.
- Published
- 2001
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