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1.  Tissue Plasminogen Activator Prevents Mortality from Sulfur Mustard Analog–Induced Airway Obstruction 
Sulfur mustard (SM) inhalation causes the rare but life-threatening disorder of plastic bronchitis, characterized by bronchial cast formation, resulting in severe airway obstruction that can lead to respiratory failure and death. Mortality in those requiring intubation is greater than 80%. To date, no antidote exists for SM toxicity. In addition, therapies for plastic bronchitis are solely anecdotal, due to lack of systematic research available to assess drug efficacy in improving mortality and/or morbidity. Adult rats exposed to SM analog were treated with intratracheal tissue plasminogen activator (tPA) (0.15–0.7 mg/kg, 5.5 and 6.5 h), compared with controls (no treatment, isoflurane, and placebo). Respiratory distress and pulse oximetry were assessed (for 12 or 48 h), and arterial blood gases were obtained at study termination (12 h). Microdissection of fixed lungs was done to assess airway obstruction by casts. Optimal intratracheal tPA treatment (0.7 mg/kg) completely eliminated mortality (0% at 48 h), and greatly improved morbidity in this nearly uniformly fatal disease model (90–100% mortality at 48 h). tPA normalized plastic bronchitis–associated hypoxemia, hypercarbia, and lactic acidosis, and improved respiratory distress (i.e., clinical scores) while decreasing airway fibrin casts. Intratracheal tPA diminished airway-obstructive fibrin–containing casts while improving clinical respiratory distress, pulmonary gas exchange, tissue oxygenation, and oxygen utilization in our model of severe chemically induced plastic bronchitis. Most importantly, mortality, which was associated with hypoxemia and clinical respiratory distress, was eliminated.
doi:10.1165/rcmb.2012-0177OC
PMCID: PMC3653605  PMID: 23258228
plastic bronchitis; tissue plasminogen activator; airway obstruction; sulfur mustard; fibrin
2.  Tissue Factor Signals Airway Epithelial Basal Cell Survival via Coagulation and Protease-Activated Receptor Isoforms 1 and 2 
Tissue factor (TF) initiates the extrinsic coagulation cascade and is a high-affinity receptor for coagulation factor VII. TF also participates in protease-activated receptor (PAR)1 and PAR2 activation. Human epithelial basal cells were previously purified on the basis of TF expression. The purpose of this study was to determine if tracheobronchial epithelial basal cell–associated TF drives coagulation and/or activates PARs to promote basal cell functions. We used human tracheobronchial tissues to isolate human airway epithelial cells using specific cell surface markers by flow cytometry and studied TF expression by immunostaining. TF-dependent fibrin network formation was observed by confocal and scanning electron microscopy. TF knockdown was done using short hairpin RNA, and TF mRNA was measured using quantitative RT-PCR. We found that 97 ± 5% of first-passage human tracheobronchial epithelial cells were basal cells, and 100% of these basal cells expressed TF. Basal cell–associated TF was active, but TF activity was dependent on added extrinsic coagulation cascade factors. TF inhibition caused basal cell apoptosis and necrosis. This was due to two parallel but interdependent TF-regulated processes: failure to generate a basal cell–associated fibrin network and suboptimal PAR1 and PAR2 activity. The data indicate that membrane surface TF mediates airway epithelial basal cell attachment, which maintains cell survival and mitotic potential. The implications of these findings are discussed in the context of basal cell–associated TF activity in normal and injured tissues and of the potential for repair of airway epithelium in lung disease.
doi:10.1165/rcmb.2012-0189OC
PMCID: PMC3547080  PMID: 23065128
tissue factor; epithelium; clotting; fibrin; tracheobronchial
3.  Interaction and Localization of Synthetic Nanoparticles in Healthy and Cystic Fibrosis Airway Epithelial Cells: Effect of Ozone Exposure 
Abstract
Background
Nanoparticles (NPs) produced by nanotechnology processes have taken the field of medicine by storm. Concerns about safety of these NPs in humans, however, have recently been raised. Although studies of NP toxicity have focused on lung disease the mechanistic link between NP exposure and lung injury remained unclear. This is primarily due to a lack of availability of appropriate airway disease models and sophisticated microscopic techniques to study nano-sized particulate delivery and resulting responses.
Methods
Air–liquid interface (ALI) cultures of non-cystic fibrosis (CF) and CF airway epithelial cells were exposed to the FITC-labeled NPs using a PennCentury microsprayer™. Uptake of NPs was assessed by FACS. Laser scanning microscopy (LSM) was performed and the images were analyzed by an advanced imaging software to study particle deposition and uptake.
Results
Flow cytometry data revealed that CF cells accumulated increased amounts of NPs. The increased NP uptake could be attributed to the reduced CF transmembrane conductance regulator (CFTR) function as a similar increased retention/uptake was observed in cells whose CFTR expression was downregulated by antisense oligonucleotide. NPs alone did not induce pro-inflammatory cytokine release or cell death. The cell culture system was sensitive to ozone but exposure to the uncoated synthetic NPs used in this study, did not cause any synergistic or suppressive effects. LSM imaging and subsequent image restoration further indicated particle uptake and intracellular localization. Exposure to ozone increased nuclear uptake in both non-CF and CF cells.
Conclusion
Our findings demonstrate the uptake of NPs using ALI cultures of non-CF and CF airway epithelial cells. The NPs used here were useful in demonstrating uptake by airway epithelial cells without causing adverse effects in presence or absence of ozone. However, to totally exclude toxic effects, chronic studies under in vivo conditions using coated particulates are required.
doi:10.1089/jamp.2011.0889
PMCID: PMC3311910  PMID: 22007674
aerosol distribution; modeling; toxicology
4.  Role of Reactive Oxygen and Nitrogen Species in Olfactory Epithelial Injury by the Sulfur Mustard Analogue 2-Chloroethyl Ethyl Sulfide 
The inhalation of sulfur mustard (SM) causes substantial deposition in the nasal region. However, specific injury has not been characterized. 2-chloroethyl ethyl sulfide (CEES) is an SM analogue used to model injury and screen potential therapeutics. After the inhalation of CEES, damage to the olfactory epithelium (OE) was extensive. Terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling-positive cells were present by 4 hours, and maximal at 18–72 hours. Cleaved caspase 3 immunohistochemistry (IHC) was maximal at 18 hours after the inhalation of 5% CEES. Olfactory marker protein (OMP)–positive olfactory neurons were markedly decreased at 18 hours. IHC-positive cells for 3-nitrotyrosine (3-NT) within epithelium were elevated by 8 hours, waning by 18 hours, and absent by 72 hours. AEOL 10150, a catalytic manganoporphyrin antioxidant, administered both subcutaneously (5 mg/kg) and intranasally (50 μM, “combined treatment”), decreased OE injury. CEES-induced increases in markers of cell death were decreased by combined treatment involving AEOL 10150. CEES-induced changes in OMP and 3-NT immunostaining were markedly improved by combined treatment involving AEOL 10150. The selective inducible nitric oxide synthase inhibitor 1400W (5 mg/kg, subcutaneous), administered 1 hour after inhalation and thereafter every 4 hours (five doses), also reduced OE damage with improved OMP and 3-NT staining. Taken together, these data indicate that reactive oxygen and nitrogen species are important mediators in CEES-induced nasal injury.
doi:10.1165/rcmb.2010-0214OC
PMCID: PMC3175559  PMID: 21642592
sulfur mustard; olfactory; cell death; oxidative stress; antioxidants
5.  Treatment with the catalytic metalloporphyrin AEOL 10150 reduces inflammation and oxidative stress due to inhalation of sulfur mustard analog 2-chloroethyl ethyl sulfide (CEES) 
Free radical biology & medicine  2010;48(9):1188-1196.
Sulfur mustard (bis-2-(chloroethyl) sulfide, SM) is a highly reactive vesicating and alkylating chemical warfare agent. A SM analog, 2-chloroethyl ethyl sulfide (CEES) has been utilized to elucidate mechanisms of toxicity and as a screen for therapeutics. Previous studies with SM and CEES have demonstrated a role for oxidative stress as well as decreased injury with antioxidant treatment. We tested whether post-treatment with the metalloporphyrin catalytic antioxidant AEOL 10150 would improve outcome in CEES-induced lung injury. Anesthetized rats inhaled 5% CEES for 15 minutes via a nose-only inhalation system. At one and nine hours following CEES exposure, rats were given AEOL 10150 (5 mg/kg, SC). At 18 hours post exposure BALF lactate dehydrogenase activity, protein, IgM, red blood cells and neutrophils were elevated following CEES exposure, and decreased by AEOL 10150 treatment. Lung myeloperoxidase activity was increased after CEES inhalation and was ameliorated by AEOL 10150. Lung oxidative stress markers 8-OHdG and 4-HNE were elevated after CEES exposure and significantly decreased by AEOL 10150 treatment. These findings demonstrate that CEES inhalation increased lung injury, inflammation, and oxidative stress, and AEOL 10150 was an effective rescue agent. Further investigation utilizing catalytic antioxidants as treatment for SM inhalation injury is warranted.
doi:10.1016/j.freeradbiomed.2010.01.039
PMCID: PMC2847650  PMID: 20138141
6.  Apoptosis induced by ozone and oxysterols in human alveolar epithelial cells 
Free radical biology & medicine  2010;48(11):1513-1524.
The mechanism of ozone-induced lung cell injury is poorly understood. One hypothesis is that ozone induces lipid peroxidation and that these peroxidased lipids produce oxidative stress and DNA damage. Oxysterols are lipid peroxide formed by the direct effect of ozone on pulmonary surfactant and cell membranes. We studied the effects of ozone and the oxysterol 5β,6β-epoxycholesterol (β-epoxide) and its metabolite cholestan-6-oxo-3,5-diol (6-oxo-3,5-diol) on human alveolar epithelial type I-like cells (ATI-like cells) and type II cells (ATII cells). Ozone and oxysterols induced apoptosis and cytotoxicity in ATI-like cells. They also generated reactive oxygen species and DNA damage. Ozone and β-epoxide were strong inducers of nuclear factor erythroid 2-related factor 2 (Nrf2), heat shock protein 70 (Hsp70) and Fos-related antigen 1 (Fra1) protein expressions. Furthermore, we found higher sensitivity of ATI-like cells than ATII cells exposed to ozone or treated with β-epoxide or 6-oxo-3,5-diol. In general the response to the cholesterol epoxides was similar to the effect of ozone. The importance of understanding the response of human ATI-like cells and ATII cells to oxysterols may be useful for further studies, because these compounds may represent useful biomarkers in other diseases.
doi:10.1016/j.freeradbiomed.2010.02.032
PMCID: PMC2965594  PMID: 20219673
alveolar type I-like cells; ozone; oxysterols; apoptosis
7.  Leukotriene B4 Release from Mast Cells in IgE-Mediated Airway Hyperresponsiveness and Inflammation 
Previous studies have shown that leukotriene B4 (LTB4), a proinflammatory lipid mediator, is linked to the development of airway hyperresponsiveness through the accumulation of IL-13–producing CD8+ T cells, which express a high affinity receptor for LTB4, BLT1 (Miyahara et al., Am J Respir Crit Care Med 2005;172:161–167; J Immunol 2005;174:4979–4984). By using leukotriene A4 hydrolase–deficient (LTA4H−/−) mice, which fail to synthesize LTB4, we determined the role of this lipid mediator in allergen-induced airway responses. Two approaches were used. In the first, LTA4H−/− mice and wild-type (LTA4H+/+) mice were systemically sensitized and challenged via the airways to ovalbumin. In the second, mice were passively sensitized with anti-ovalbumin IgE and exposed to ovalbumin via the airways. Mast cells were generated from bone marrow of LTA4H+/+ mice or LTA4H−/− mice. After active sensitization and challenge, LTA4H−/− mice showed significantly lower airway hyperresponsiveness compared with LTA4H+/+ mice, and eosinophil numbers and IL-13 levels in the bronchoalveoloar lavage of LTA4H−/− mice were also significantly lower. LTA4H−/− mice also showed decreased airway reactivity after passive sensitization and challenge. After LTA4H+/+ mast cell transfer, LTA4H−/− mice showed increased airway reactivity after passive sensitization and challenge, but not after systemic sensitization and challenge. These data confirm the important role for LTB4 in the development of altered airway responses and suggest that LTB4 secretion from mast cells is critical to eliciting increased airway reactivity after passive sensitization with allergen-specific IgE.
doi:10.1165/rcmb.2008-0095OC
PMCID: PMC2689918  PMID: 19029019
rodent; T cells; cytokines; lipid mediators; lung
8.  Bcl-2 Suppresses Sarcoplasmic/Endoplasmic Reticulum Ca2+-ATPase Expression in Cystic Fibrosis Airways 
Rationale: Modulation of the activity of sarcoendoplasmic reticulum calcium ATPase (SERCA) can profoundly affect Ca2+ homeostasis. Although altered calcium homeostasis is a characteristic of cystic fibrosis (CF), the role of SERCA is unknown.
Objectives: This study provides a comprehensive investigation of expression and activity of SERCA in CF airway epithelium. A detailed study of the mechanisms underlying SERCA changes and its consequences was also undertaken.
Methods: Lung tissue samples (bronchus and bronchiole) from subjects with and without CF were evaluated by immunohistochemistry. Protein and mRNA expression in primary non-CF and CF cells was determined by Western and Northern blots.
Measurements and Main Results: SERCA2 expression was decreased in bronchial and bronchiolar epithelia of subjects with CF. SERCA2 expression in lysates of polarized tracheobronchial epithelial cells from subjects with CF was decreased by 67% as compared with those from subjects without CF. Several non-CF and CF airway epithelial cell lines were also probed. SERCA2 expression and activity were consistently decreased in CF cell lines. Adenoviral expression of mutant F508 cystic fibrosis transmembrane regulator gene (CFTR), inhibition of CFTR function pharmacologically (CFTRinh172), or stable expression of antisense oligonucleotides to inhibit CFTR expression caused decreased SERCA2 expression. In CF cells, SERCA2 interacted with Bcl-2, leading to its displacement from caveolae-related domains of endoplasmic reticulum membranes, as demonstrated in sucrose density gradient centrifugation and immunoprecipitation studies. Knockdown of SERCA2 using siRNA enhanced epithelial cell death due to ozone, hydrogen peroxide, and TNF-α.
Conclusions: Reduced SERCA2 expression may alter calcium signaling and apoptosis in CF. These findings decrease the likelihood of therapeutic benefit of SERCA inhibition in CF.
doi:10.1164/rccm.200807-1104OC
PMCID: PMC2675566  PMID: 19201925
cystic fibrosis; SERCA2; pulmonary epithelium; ER
9.  Estrogen Determines Sex Differences in Airway Responsiveness after Allergen Exposure 
The female hormone estrogen is an important factor in the regulation of airway function and inflammation, and sex differences in the prevalence of asthma are well described. Using an animal model, we determined how sex differences may underlie the development of altered airway function in response to allergen exposure. We compared sex differences in the development of airway hyperresponsiveness (AHR) after allergen exposure exclusively via the airways. Ovalbumin (OVA) was administered by nebulization on 10 consecutive days in BALB/c mice. After methacholine challenge, significant AHR developed in male mice but not in female mice. Ovariectomized female mice showed significant AHR after 10-day OVA inhalation. ICI182,780, an estrogen antagonist, similarly enhanced airway responsiveness even when administered 1 hour before assay. In contrast, 17β-estradiol dose-dependently suppressed AHR in male mice. In all cases, airway responsiveness was inhibited by the administration of a neurokinin 1 receptor antagonist. These results demonstrate that sex differences in 10-day OVA-induced AHR are due to endogenous estrogen, which negatively regulates airway responsiveness in female mice. Cumulatively, the results suggest that endogenous estrogen may regulate the neurokinin 1–dependent prejunctional activation of airway smooth muscle in allergen-exposed mice.
doi:10.1165/rcmb.2007-0298OC
PMCID: PMC2335333  PMID: 18063836
estrogen; sex; airway hyperresponsiveness; EFS; neuronal activation
10.  Spontaneous Airway Hyperresponsiveness in Estrogen Receptor-α–deficient Mice 
Rationale: Airway hyperresponsiveness is a critical feature of asthma. Substantial epidemiologic evidence supports a role for female sex hormones in modulating lung function and airway hyperresponsiveness in humans.
Objectives: To examine the role of estrogen receptors in modulating lung function and airway responsiveness using estrogen receptor–deficient mice.
Methods: Lung function was assessed by a combination of whole-body barometric plethysmography, invasive measurement of airway resistance, and isometric force measurements in isolated bronchial rings. M2 muscarinic receptor expression was assessed by Western blotting, and function was assessed by electrical field stimulation of tracheas in the presence/absence of gallamine. Allergic airway disease was examined after ovalbumin sensitization and exposure.
Measurements and Main Results: Estrogen receptor-α knockout mice exhibit a variety of lung function abnormalities and have enhanced airway responsiveness to inhaled methacholine and serotonin under basal conditions. This is associated with reduced M2 muscarinic receptor expression and function in the lungs. Absence of estrogen receptor-α also leads to increased airway responsiveness without increased inflammation after allergen sensitization and challenge.
Conclusions: These data suggest that estrogen receptor-α is a critical regulator of airway hyperresponsiveness in mice.
doi:10.1164/rccm.200509-1493OC
PMCID: PMC1899278  PMID: 17095746
lung function; asthma; hyperreactivity; M2 muscarinic receptor; estrogen receptor
11.  Spontaneous Airway Hyperresponsiveness in Estrogen Receptor-α–deficient Mice 
Rationale
Airway hyperresponsiveness is a critical feature of asthma. Substantial epidemiologic evidence supports a role for female sex hormones in modulating lung function and airway hyperresponsiveness in humans.
Objectives
To examine the role of estrogen receptors in modulating lung function and airway responsiveness using estrogen receptor–deficient mice.
Methods
Lung function was assessed by a combination of whole-body barometric plethysmography, invasive measurement of airway resistance, and isometric force measurements in isolated bronchial rings. M2 muscarinic receptor expression was assessed by Western blotting, and function was assessed by electrical field stimulation of tracheas in the presence/absence of gallamine. Allergic airway disease was examined after ovalbumin sensitization and exposure.
Measurements and Main Results
Estrogen receptor-α knockout mice exhibit a variety of lung function abnormalities and have enhanced airway responsiveness to inhaled methacholine and serotonin under basal conditions. This is associated with reduced M2 muscarinic receptor expression and function in the lungs. Absence of estrogen receptor-α also leads to increased airway responsiveness without increased inflammation after allergen sensitization and challenge.
Conclusions
These data suggest that estrogen receptor-α is a critical regulator of airway hyperresponsiveness in mice.
doi:10.1164/rccm.200509-1493OC
PMCID: PMC1899278  PMID: 17095746
lung function; asthma; hyperreactivity; M2 muscarinic receptor; estrogen receptor
12.  Inhibition of Spleen Tyrosine Kinase Prevents Mast Cell Activation and Airway Hyperresponsiveness 
Rationale: Spleen tyrosine kinase (Syk) is important for Fc and B-cell receptor–mediated signaling.
Objective: To determine the activity of a specific Syk inhibitor (R406) on mast cell activation in vitro and on the development of allergen-induced airway hyperresponsiveness (AHR) and inflammation in vivo.
Methods: AHR and inflammation were induced after 10 d of allergen (ovalbumin [OVA]) exposure exclusively via the airways and in the absence of adjuvant. This approach was previously established to be IgE, FcɛRI, and mast cell dependent. Alternatively, mice were passively sensitized with OVA-specific IgE, followed by limited airway challenge. In vitro, the inhibitor was added to cultures of IgE-sensitized bone marrow–derived mast cells (BMMCs) before cross-linking with allergen.
Results: The inhibitor prevented OVA-induced degranulation of passively IgE-sensitized murine BMMCs and inhibited the production of interleukin (IL)-13, tumor necrosis factor α, IL-2, and IL-6 in these sensitized BMMCs. When administered in vivo, R406 inhibited AHR, which developed in BALB/c mice exposed to aerosolized 1% OVA for 10 consecutive d (20 min/d), as well as pulmonary eosinophilia and goblet cell metaplasia. A similar inhibition of AHR was demonstrated in mice passively sensitized with OVA-specific IgE and exposed to limited airway challenge.
Conclusion: This study delineates a functional role for Syk in the development of mast cell– and IgE-mediated AHR and airway inflammation, and these results indicate that inhibition of Syk may be a target in the treatment of allergic asthma.
doi:10.1164/rccm.200503-361OC
PMCID: PMC2662982  PMID: 16192454
airway hyperresponsiveness; eosinophils; goblet cell metaplasia; mast cells; spleen tyrosine kinase

Results 1-12 (12)