Glutathione peroxidase activity and mRNA expression in eosinophils and neutrophils of asthmatic and non-asthmatic subjects

Abstract

Asthma has been reported to be associated with a reduction in the activity of glutathione peroxidase (GSH-Px), an important antioxidant enzyme. However, the expression of GSH-Px enzyme activity has not previously been investigated in human eosinophils, which are important inflammatory cells involved in asthma. Reverse transcriptasepolymerase chain reaction and Southern blotting demonstrated that eosinophils express GSH-Px mRNA and the relative expression of GSH-Px was greater in eosinophils than in neutrophils for both asthmatic and non-asthmatic subjects. The presence of GSH-Px protein in eosinophil and neutrophil lysates was confirmed by size exclusion chromatography and by Western blotting. GSH-Px enzyme activity as measured by a spectrophotometric assay was greater in eosinophil (48.4 ؎ 1.6 mol NADPH oxidized · min ؊1 · g ؊1 protein) than in neutrophil lysates (18.1 ؎ 0.4, n ‫؍‬ 24, P F 0.0001). GSH-Px activities of eosinophils and neutrophils from asthmatic subjects did not differ from those of nonasthmatic subjects. Eosinophil GSH-Px activity was correlated with peripheral blood eosinophil count only in asthmatic subjects (r s ‫؍‬ 0.59, n ‫؍‬ 12, P ‫؍‬ 0.04). Increased GSH-Px expression in eosinophils compared with neutrophils of asthmatic patients may provide antioxidant protection against the greater amounts of reactive oxygen species generated by these cells and may enhance the survival of eosinophils at sites of inflammation in asthma.

Deranged Bioenergetics and Defective Redox Capacity in T Lymphocytes and Neutrophils Are Related to Cellular Dysfunction and Increased Oxidative Stress in Patients with Active Systemic Lupus Erythematosus

“…In contrast, PMN expressed mainly monomer and trimer isomers, rather than dimer and tetramer isomers, of GSH-Px. These results are compatible with those of Misso et al [30], who showed that normal neutrophils contain mainly monomer and trimer isoforms of GSH-Px. Because the GSH-Px enzymatic activity of T lymphocytes is much higher than that of PMN, we speculated that the dimer and tetramer isoforms of GSH-Px may possess more potent antioxidant activity than the monomer and trimer isoforms.…”

“…In addition, compared to normal cells, SLE-T and SLE-PMN tend to have decreased ATP production (Figure 1(d)). This decreased ATP production reflects mitochondrial functions impaired by activation-induced cell death [36, 37] and decreased redox capacity in SLE [2, 4, 30]. Abnormal glucose bioenergetics in SLE cells owing to defective expression of GLUT-3 and GLUT-6 on the cell surface can lead to impaired immune functions in active SLE.…”

Comparison of kinin B1 and B2 receptor expression in neutrophils of asthmatic and non-asthmatic subjects

“…Neutrophils were isolated by centrifugation of whole blood on Percoll (density 1.088, GE Healthcare Bio-Sciences, Sydney, Australia), followed by hypotonic lysis of erythrocytes and immunomagnetic selection of neutrophils using CD16 microbeads (MACS, Miltenyi Biotec, Sydney, Australia), as previously described [17].…”

Selenium status in patients with aspirin-induced asthma

“…It is also possible that increased GPX activity might relate to over-expression of the GPX gene. Misso et al 39 showed increased expression of GPX mRNA in eosinophils from AIA patients. Comhair et al 40 reported an eight-fold increase in GPX mRNA in bronchial epithelial cells after exposure to reactive-oxygen species and glutathione, a cofactor for GPX.…”