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Background: Even though the systemic level of SCCA1, a serine protease inhibitor, was shown to be elevated in asthma, its physiological role is unknown. Objective: We sought to determine the effect of SCCA1 on apoptosis, cytokine expression and mucus production by A549 cells and define the effect of promoter variants on gene expression and association with asthma. Methods: SCCA levels were measured by ELISA. Promoter variants were determined by direct sequencing. 442 asthmatic children and 191 controls were genotyped by RFLP. The functional effect of the polymorphisms was assessed in transient transfection experiments using reporter constructs. A transcription factor ELISA was used for differential binding of GATA proteins to the variant region. The effects of SCCA1 on cytokine synthesis, mucus production and apoptosis were determined in A549 cells transfected with SCCA1 pcDNA vector. MUC5AC expression in A549 cells was determined with RT-PCR. Results: SCCA1 protein level was significantly higher in asthmatic children compared to healthy controls. Four polymorphisms SCCA1 promoter that were in linkage disequilibrium were associated with skin test positivity in asthmatic children and showed higher promoter activity and higher binding of GATA-2 and GATA-3 after IL-4 + IL-13 stimulation. IL-6, IL-8 levels were significantly higher in cells transfected with SCCA1 whereas RANTES increased only after IL-4 stimulation. Transfection of A549 cells with SCCA1 resulted in decreased MUC5AC expression and conferred protection against apoptosis. Conclusion: Our results showed that SCCA1 has diverse effects on many of the cellular events that characterize asthma and its role extends beyond protease inhibition. [ABSTRACT FROM AUTHOR]

Background: Even though there is ample evidence on the oxidative stress in asthma, there is limited information on the antioxidant defense systems. Objectives: To conduct a comprehensive evaluation of various components of both enzymatic and nonenzymatic antioxidants in a large group of children with asthma. Methods: A total of 164 children with mild asthma and 173 healthy children were included in the study. Levels of the enzymes glutathione peroxidase and superoxide dismutase were measured by using ELISA, whereas reduced glutathione, ascorbic acid, α-tocopherol, lycopene, β-carotene, amino acids participating in glutathione synthesis, and amino acids susceptible to oxidation were measured by HPLC. All comparisons were adjusted for atopy, body mass index, smoke exposure, and pet ownership. Results: Levels of the enzymes glutathione peroxidase and superoxide dismutase and of the nonenzymatic components of the antioxidant system including reduced glutathione, ascorbic acid, α-tocopherol, lycopene, and β-carotene were significantly lower in children with asthma compared with healthy controls (P < .001 for each). Of the amino acids contributing to glutathione synthesis, glycine and glutamine were significantly lower in children with asthma (P < .001). The majority of the amino acid susceptible to oxidative stress displayed lower levels in children with asthma (P < .05). Conclusion: Childhood asthma is associated with significant decreases in various components of both enzymatic and nonenzymatic antioxidant defenses. [Copyright &y& Elsevier]

Background: The factors contributing to the oxidant/antioxidant imbalance in asthma are incompletely understood. Objective: To determine the factors associated with oxidative stress including asthma severity and the genotype of the antioxidant enzymes. Methods: A total of 196 children with mild asthma, 116 children with moderate-severe asthma, and 2 healthy control groups (187 and 68 children) were included in the study. Plasma levels of malondialdehyde were measured as the indicator of oxidative stress, and reduced glutathione levels as the indicator of antioxidant defense. Children were genotyped for null variants of glutathione S transferase (GST) T1 and GSTM1, and ile105val variant of GSTP1. Risk factors were analyzed with multivariate logistic regression. Results: Systemic levels of malondialdehyde increased and reduced glutathione levels decreased significantly from healthy controls to patients with mild asthma and then to patients with moderate-severe asthma (P < .001 for each). Multivariate logistic regression identified asthma and asthma severity as independent factors associated with oxidative stress (odds ratio between 17 and 56; P < .001). Children with asthma with GSTP1 val/val genotype had higher malondialdehyde and lower glutathione levels compared with other genotypes (P = .023 and P = .014, respectively). GSTP1 val/val genotype was independently associated with asthma severity (odds ratio, 4.210; 95% CI, 1.581-11.214; P = .004). Conclusion: Our study indicates the presence of a strong oxidative stress in children with asthma that increases with the severity of the disease. In this population, val/val genotype at GSTP1 ile105val locus may be an important factor in determining the degree of oxidant injury. Clinical implications: Children with asthma with val/val genotype at GSTP1 ile105val locus may be good candidates for supplemental antioxidant therapy. [Copyright &y& Elsevier]

The imbalance between reactive oxygen species (ROS) and the antioxidant response has been linked to various airway diseases, including asthma. However, knowledge on cell-specific responses of the airway resident and inflammatory cells against increased oxidant stress is very limited. We aim to better understand the cell-specific antioxidant response that contributes to the pathophysiology of lung disease in response to oxidative stress. The human cell lines of epithelial, fibroblast, endothelial, monocyte, eosinophil and neutrophil were incubated with tert-butyl hydroperoxide (tBHP) or cigarette smoke condensate (CSC). Following stimulation, cell viability, total oxidant and antioxidant activity were assessed in both residential and inflammatory cells. Human Oxidative Stress Plus RT2 Profiler PCR array was used to determine 84 gene expression differences in oxidant and antioxidant pathways following oxidant stimulus in all cells. We showed that various cell types respond differently to oxidative stress inducers, with distinct gene expression and oxidant-antioxidant generation. Most importantly, eosinophils increased the activity of all main antioxidant enzymes in response to both oxidants. Monocytes, on the other hand, showed no change in response to each stimulation, whereas neutrophils only increased their CAT activity in response to both stimuli. The increase in NRF2-regulated genes HSPA1A , HMOX1 and DUSP1 after both tBHP and CSC in epithelial cells and fibroblasts indicates Nfr2 pathway activation. This study advances our knowledge of the molecular and cellular mechanisms of cell-specific antioxidant response upon exposure to oxidative stress. Additionally, our observations imply that the eosinophils' distinct biological response may be utilized for endotype-based cell-targeted antioxidant therapy. [Display omitted] • The antioxidant response of lung-resident and inflammatory cells differs by cell type and source of oxidative stress. • Eosinophils respond uniquely to tBHP and CSC with increased activity of antioxidants, which may help treat T2-type asthma. • This study provides potential support for cell-based antioxidant therapy, noting that each cell has a unique redox response. [ABSTRACT FROM AUTHOR]