Exposure to naphthalene induces naphthyl-keratin adducts in human epidermis in vitro and in vivo

We observed naphthyl-keratin adducts and dose-related metabolic enzyme induction at the mRNA level in reconstructed human epidermis in vitro after exposure to naphthalene. Immunofluorescence detection of 2-naphthyl-keratin-1 adducts confirmed the metabolism of naphthalene and adduction of keratin. We also observed naphthyl-keratin adducts in dermal tape-strip samples collected from naphthalene-exposed workers at levels ranging from 0.004 to 6.104 pmole adduct/μg keratin. We have demonstrated the ability of the human skin to metabolize naphthalene and to form naphthyl-keratin adducts both in vitro and in vivo. The results indicate the potential use of keratin adducts as biomarkers of dermal exposure

Single-Nucleotide Polymorphisms Associated with Skin Naphthyl–Keratin Adduct Levels in Workers Exposed to Naphthalene

Background: Individual genetic variation that results in differences in systemic response to xenobiotic exposure is not accounted for as a predictor of outcome in current exposure assessment models

Inter-α-Inhibitor Blocks Epithelial Sodium Channel Activation and Decreases Nasal Potential Differences in ΔF508 Mice

Increased activity of lung epithelial sodium channels (ENaCs) contributes to the pathophysiology of cystic fibrosis (CF) by increasing the rate of epithelial lining fluid reabsorption. Inter-α-inhibitor (IαI), a serum protease inhibitor, may decrease ENaC activity by preventing its cleavage by serine proteases. High concentrations of IαI were detected in the bronchoalveolar lavage fluid (BALF) of children with CF and lower airway diseases. IαI decreased amiloride-sensitive (IENaC) but not cAMP-activated Cl− currents across confluent monolayers of rat ATII, and mouse nasal epithelial cells grew in primary culture by 45 and 25%, respectively. Changes in IENaC by IαI in ATII cells were accompanied by increased levels of uncleaved (immature) surface α-ENaC. IαI increased airway surface liquid depth overlying murine nasal epithelial cells to the same extent as amiloride, consistent with ENaC inhibition. Incubation of lung slices from C57BL/6, those lacking phenylalanine at position 508 (∆F508), or CF transmembrane conductance regulator knockout mice with IαI for 3 hours decreased the open probability of their ENaC channels by 50%. ∆F508 mice had considerably higher levels the amiloride-sensitive fractions of ENaC nasal potential difference (ENaC-NPD) than wild-type littermates and only background levels of IαI in their BALF. A single intranasal instillation of IαI decreased their ENaC-NPD 24 hours later by 25%. In conclusion, we show that IαI is present in the BALF of children with CF, is an effective inhibitor of ENaC proteolysis, and decreases ENaC activity in lung epithelial cells of ∆F508 mice

Effects of inhaled high-molecular weight hyaluronan in inflammatory airway disease

© 2016 The Author(s).Cystic fibrosis (CF) is a chronic inflammatory disease that is affecting thousands of patients worldwide. Adjuvant anti-inflammatory treatment is an important component of cystic fibrosis treatment, and has shown promise in preserving lung function and prolonging life expectancy. Inhaled high molecular weight hyaluronan (HMW-HA) is reported to improve tolerability of hypertonic saline and thus increase compliance, and has been approved in some European countries for use as an adjunct to hypertonic saline treatment in cystic fibrosis. However, there are theoretical concerns that HMW-HA breakdown products may be pro-inflammatory. In this clinical pilot study we show that sputum cytokines in CF patients receiving HMW-HA are not increased, and therefore HMW-HA does not appear to adversely affect inflammatory status in CF airways.This work was funded by the Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health

TLR5 participates in the TLR4 receptor complex and promotes MyD88- dependent signaling in environmental lung injury

Lung disease causes significant morbidity and mortality, and is exacerbated by environmental injury, for example through lipopolysaccharide (LPS) or ozone (O3). Toll-like receptors (TLRs) orchestrate immune responses to injury by recognizing pathogen- or danger-associated molecular patterns. TLR4, the prototypic receptor for LPS, also mediates inflammation after O3, triggered by endogenous hyaluronan. Regulation of TLR4 signaling is incompletely understood. TLR5, the flagellin receptor, is expressed in alveolar macrophages, and regulates immune responses to environmental injury. Using in vivo animal models of TLR4-mediated inflammations (LPS, O3, hyaluronan), we show that TLR5 impacts the in vivo response to LPS, hyaluronan and O3. We demonstrate that immune cells of human carriers of a dominant negative TLR5 allele have decreased inflammatory response to O3 exposure ex vivo and LPS exposure in vitro. Using primary murine macrophages, we find that TLR5 physically associates with TLR4 and biases TLR4 signaling towards the MyD88 pathway. Our results suggest an updated paradigm for TLR4/TLR5 signaling

TLR4 Is Necessary for Hyaluronan-mediated Airway Hyperresponsiveness after Ozone Inhalation

Rationale: Ozone is a common environmental air pollutant that contributes to hospitalizations for respiratory illness. The mechanisms, which regulate ozone-induced airway hyperresponsiveness, remain poorly understood. We have previously reported that toll-like receptor 4 (TLR4)–deficient animals are protected against ozone-induced airway hyperresponsiveness (AHR) and that hyaluronan (HA) mediates ozone-induced AHR. However, the relation between TLR4 and hyaluronan in the airway response to ozone remains unexplored

Inter-α-Inhibitor Blocks Epithelial Sodium Channel Activation and Decreases Nasal Potential Differences in ΔF508 Mice

Increased activity of lung epithelial sodium channels (ENaCs) contributes to the pathophysiology of cystic fibrosis (CF) by increasing the rate of epithelial lining fluid reabsorption. Inter-α-inhibitor (IαI), a serum protease inhibitor, may decrease ENaC activity by preventing its cleavage by serine proteases. High concentrations of IαI were detected in the bronchoalveolar lavage fluid (BALF) of children with CF and lower airway diseases. IαI decreased amiloride-sensitive (I(ENaC)) but not cAMP-activated Cl(−) currents across confluent monolayers of rat ATII, and mouse nasal epithelial cells grew in primary culture by 45 and 25%, respectively. Changes in I(ENaC) by IαI in ATII cells were accompanied by increased levels of uncleaved (immature) surface α-ENaC. IαI increased airway surface liquid depth overlying murine nasal epithelial cells to the same extent as amiloride, consistent with ENaC inhibition. Incubation of lung slices from C57BL/6, those lacking phenylalanine at position 508 (∆F508), or CF transmembrane conductance regulator knockout mice with IαI for 3 hours decreased the open probability of their ENaC channels by 50%. ∆F508 mice had considerably higher levels the amiloride-sensitive fractions of ENaC nasal potential difference (ENaC-NPD) than wild-type littermates and only background levels of IαI in their BALF. A single intranasal instillation of IαI decreased their ENaC-NPD 24 hours later by 25%. In conclusion, we show that IαI is present in the BALF of children with CF, is an effective inhibitor of ENaC proteolysis, and decreases ENaC activity in lung epithelial cells of ∆F508 mice