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Glutathione-S-transferases in lung and sputum specimens, effects of smoking and COPD severity.

Harju T, Mazur W, Merikallio H, Soini Y, Kinnula VL - Respir. Res. (2008)

Bottom Line: GST pi was present in airway and alveolar epithelium as well as in alveolar macrophages.GST mu was expressed mainly in the epithelium.The presence of GSTs in the airway secretions points to their potential protective role both as intracellular and extracellular mediators in human lung.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Clinical Medicine, Department of Internal Medicine, Centre of Excellence in Research, P O Box 5000, 90014 University of Oulu, Oulu, Finland. terttu.harju@oulu.fi

ABSTRACT

Background: Oxidative stress plays a potential role in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). Glutathione S-transferases (GSTs) detoxify toxic compounds in tobacco smoke via glutathione-dependent mechanisms. Little is known about the regulation and expression of GSTs in COPD lung and their presence in airway secretions.

Methods: GST alpha, pi and mu were investigated by immunohistochemistry in 72 lung tissue specimens and by Western analysis in total lung homogenates and induced sputum supernatants from non-smokers, smokers and patients with variable stages of COPD severity.

Results: GST alpha was expressed mainly in the airway epithelium. The percentage of GST alpha positive epithelial cells was lower in the central airways of patients with very severe (Stage IV) COPD compared to mild/moderate COPD (p = 0.02). GST alpha by Western analysis was higher in the total lung homogenates in mild/moderate COPD compared to cases of very severe disease (p < 0.001). GST pi was present in airway and alveolar epithelium as well as in alveolar macrophages. GST mu was expressed mainly in the epithelium. Both GST alpha and pi were detectable in sputum supernatants especially in patients with COPD.

Conclusion: This study indicates the presence of GST alpha and pi especially in the epithelium and sputum supernatants in mild/moderate COPD and low expression of GST alpha in the epithelium in cases of very severe COPD. The presence of GSTs in the airway secretions points to their potential protective role both as intracellular and extracellular mediators in human lung.

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GST alpha immunoreactivity in sputum cells and supernatants. A. Western analysis for GST alpha in induced sputum supernatants revealed an increased immunoreactivity in patients with chronic bronchitis and in Stage II-III COPD compared to healthy non-smokers (p < 0.001). The means of the measured intensities are shown as columns with error bars representing SEM. B. Representative sputum cytospins from a smoker (a), patient with chronic bronchitis (b) and patient with Stage II COPD (c). Macrophages in the induced sputum exhibited positive GST alpha reactivity.
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Figure 3: GST alpha immunoreactivity in sputum cells and supernatants. A. Western analysis for GST alpha in induced sputum supernatants revealed an increased immunoreactivity in patients with chronic bronchitis and in Stage II-III COPD compared to healthy non-smokers (p < 0.001). The means of the measured intensities are shown as columns with error bars representing SEM. B. Representative sputum cytospins from a smoker (a), patient with chronic bronchitis (b) and patient with Stage II COPD (c). Macrophages in the induced sputum exhibited positive GST alpha reactivity.

Mentions: GST alpha was mainly localized in the central and peripheral airway epithelium, with some alveolar macrophages showing weak positivity (Figure 1). The intensity of GST alpha staining showed a tendency to be lower in the central airways of cases of very severe (Stage IV) COPD compared to Stage I-II COPD. Moreover, the percentage of GST alpha positive epithelial cells was significantly lower in the central airway epithelium of Stage IV COPD than in Stage I-II COPD (p = 0.02). No corresponding changes could be seen in the peripheral airway epithelium (Figure 2A, B). When the total immunoreactivity was assessed by Western analysis of the lung homogenate, GST alpha was higher in Stage I-II COPD (p < 0.001) than in Stage IV COPD (Figure 2C). Additionally, GST alpha was clearly detectable in induced sputum supernatants, being higher both in chronic bronchitis and in Stage II-III COPD than in the healthy non-smokers (Figure 3) (p < 0.001). The Western blotting of GST alpha consistently showed two bands from the tissues but not from sputum supernatants. These results can be related to many reasons one of those being proteolysis of GST alpha in the tissues. Another, even more likely reason is the presence of various alpha-class GSTs in human lung tissues but not in sputum supernatants. Two GST alpha subtypes have been earlier documented in rat tissue homogenates and porcine Sertoli cells and our results are in full agreement with those investigations [24,25]. In induced sputum cytospins, GST alpha was localized in macrophages (Figure 3). Induced sputum was not collected from very severe cases partly due to technical difficulties, only lung tissue specimens were available from the cases of very severe COPD.


Glutathione-S-transferases in lung and sputum specimens, effects of smoking and COPD severity.

Harju T, Mazur W, Merikallio H, Soini Y, Kinnula VL - Respir. Res. (2008)

GST alpha immunoreactivity in sputum cells and supernatants. A. Western analysis for GST alpha in induced sputum supernatants revealed an increased immunoreactivity in patients with chronic bronchitis and in Stage II-III COPD compared to healthy non-smokers (p < 0.001). The means of the measured intensities are shown as columns with error bars representing SEM. B. Representative sputum cytospins from a smoker (a), patient with chronic bronchitis (b) and patient with Stage II COPD (c). Macrophages in the induced sputum exhibited positive GST alpha reactivity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2654438&req=5

Figure 3: GST alpha immunoreactivity in sputum cells and supernatants. A. Western analysis for GST alpha in induced sputum supernatants revealed an increased immunoreactivity in patients with chronic bronchitis and in Stage II-III COPD compared to healthy non-smokers (p < 0.001). The means of the measured intensities are shown as columns with error bars representing SEM. B. Representative sputum cytospins from a smoker (a), patient with chronic bronchitis (b) and patient with Stage II COPD (c). Macrophages in the induced sputum exhibited positive GST alpha reactivity.
Mentions: GST alpha was mainly localized in the central and peripheral airway epithelium, with some alveolar macrophages showing weak positivity (Figure 1). The intensity of GST alpha staining showed a tendency to be lower in the central airways of cases of very severe (Stage IV) COPD compared to Stage I-II COPD. Moreover, the percentage of GST alpha positive epithelial cells was significantly lower in the central airway epithelium of Stage IV COPD than in Stage I-II COPD (p = 0.02). No corresponding changes could be seen in the peripheral airway epithelium (Figure 2A, B). When the total immunoreactivity was assessed by Western analysis of the lung homogenate, GST alpha was higher in Stage I-II COPD (p < 0.001) than in Stage IV COPD (Figure 2C). Additionally, GST alpha was clearly detectable in induced sputum supernatants, being higher both in chronic bronchitis and in Stage II-III COPD than in the healthy non-smokers (Figure 3) (p < 0.001). The Western blotting of GST alpha consistently showed two bands from the tissues but not from sputum supernatants. These results can be related to many reasons one of those being proteolysis of GST alpha in the tissues. Another, even more likely reason is the presence of various alpha-class GSTs in human lung tissues but not in sputum supernatants. Two GST alpha subtypes have been earlier documented in rat tissue homogenates and porcine Sertoli cells and our results are in full agreement with those investigations [24,25]. In induced sputum cytospins, GST alpha was localized in macrophages (Figure 3). Induced sputum was not collected from very severe cases partly due to technical difficulties, only lung tissue specimens were available from the cases of very severe COPD.

Bottom Line: GST pi was present in airway and alveolar epithelium as well as in alveolar macrophages.GST mu was expressed mainly in the epithelium.The presence of GSTs in the airway secretions points to their potential protective role both as intracellular and extracellular mediators in human lung.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Clinical Medicine, Department of Internal Medicine, Centre of Excellence in Research, P O Box 5000, 90014 University of Oulu, Oulu, Finland. terttu.harju@oulu.fi

ABSTRACT

Background: Oxidative stress plays a potential role in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). Glutathione S-transferases (GSTs) detoxify toxic compounds in tobacco smoke via glutathione-dependent mechanisms. Little is known about the regulation and expression of GSTs in COPD lung and their presence in airway secretions.

Methods: GST alpha, pi and mu were investigated by immunohistochemistry in 72 lung tissue specimens and by Western analysis in total lung homogenates and induced sputum supernatants from non-smokers, smokers and patients with variable stages of COPD severity.

Results: GST alpha was expressed mainly in the airway epithelium. The percentage of GST alpha positive epithelial cells was lower in the central airways of patients with very severe (Stage IV) COPD compared to mild/moderate COPD (p = 0.02). GST alpha by Western analysis was higher in the total lung homogenates in mild/moderate COPD compared to cases of very severe disease (p < 0.001). GST pi was present in airway and alveolar epithelium as well as in alveolar macrophages. GST mu was expressed mainly in the epithelium. Both GST alpha and pi were detectable in sputum supernatants especially in patients with COPD.

Conclusion: This study indicates the presence of GST alpha and pi especially in the epithelium and sputum supernatants in mild/moderate COPD and low expression of GST alpha in the epithelium in cases of very severe COPD. The presence of GSTs in the airway secretions points to their potential protective role both as intracellular and extracellular mediators in human lung.

Show MeSH
Related in: MedlinePlus