Modulation of glutaredoxin in the lung and sputum of cigarette smokers and chronic obstructive pulmonary disease

BACKGROUND: One typical feature in chronic obstructive pulmonary disease (COPD) is the disturbance of the oxidant/antioxidant balance. Glutaredoxins (Grx) are thiol disulfide oxido-reductases with antioxidant capacity and catalytic functions closely associated with glutathione, the major small molecular weight antioxidant of human lung. However, the role of Grxs in smoking related diseases is unclear. METHODS: Immunohistochemical and Western blot analyses were conducted with lung specimens (n = 45 and n = 32, respectively) and induced sputum (n = 50) of healthy non-smokers and smokers without COPD and at different stages of COPD. RESULTS: Grx1 was expressed mainly in alveolar macrophages. The percentage of Grx1 positive macrophages was significantly lower in GOLD stage IV COPD than in healthy smokers (p = 0.021) and the level of Grx1 in total lung homogenate decreased both in stage I–II (p = 0.045) and stage IV COPD (p = 0.022). The percentage of Grx1 positive macrophages correlated with the lung function parameters (FEV1, r = 0.45, p = 0.008; FEV1%, r = 0.46, p = 0.007, FEV/FVC%, r = 0.55, p = 0.001). Grx1 could also be detected in sputum supernatants, the levels being increased in the supernatants from acute exacerbations of COPD compared to non-smokers (p = 0.013) and smokers (p = 0.051). CONCLUSION: The present cross-sectional study showed that Grx1 was expressed mainly in alveolar macrophages, the levels being decreased in COPD patients. In addition, the results also demonstrated the presence of Grx1 in extracellular fluids including sputum supernatants. Overall, the present study suggests that Grx1 is a potential redox modulatory protein regulating the intracellular as well as extracellular homeostasis of glutathionylated proteins and GSH in human lung

SOD2 immunoexpression predicts lymph node metastasis in penile cancer

BACKGROUND: Superoxide dismutase-2 (SOD2) is considered one of the most important antioxidant enzymes that regulate cellular redox state in normal and tumorigenic cells. Overexpression of this enzyme in lung, gastric, colorectal, breast cancer and cervical cancer malignant tumors has been observed. Its relationship with inguinal lymph node metastasis in penile cancer is unknown. METHODS: SOD2 protein expression levels were determined by immunohistochemistry in 125 usual type squamous cell carcinomas of the penis from a Brazilian cancer center. The casuistic has been characterized by means of descriptive statistics. An exploratory logistic regression has been proposed to evaluate the independent predictive factors of lymph node metastasis. RESULTS: SOD2 expression in more than 50% of cells was observed in 44.8% of primary penile carcinomas of the usual type. This expression pattern was associated with lymph node metastasis both in the uni and multivariate analysis. CONCLUSIONS: Our results indicate that SOD2 expression predicts regional lymph node metastasis. The potential clinical implication of this observation warrants further studies.Dr. Lara Termini (FAPESP 2005/57274-9); Dr. Luisa Lina Villa (FAPESP 2008/57889-1 and CNPq 573799/2008-3)

Interactions among mitochondrial proteins altered in glioblastoma

Mitochondrial dysfunction is putatively central to glioblastoma (GBM) pathophysiology but there has been no systematic analysis in GBM of the proteins which are integral to mitochondrial function. Alterations in proteins in mitochondrial enriched fractions from patients with GBM were defined with label-free liquid chromatography mass spectrometry. 256 mitochondrially-associated proteins were identified in mitochondrial enriched fractions and 117 of these mitochondrial proteins were markedly (fold-change ≥2) and significantly altered in GBM (p ≤ 0.05). Proteins associated with oxidative damage (including catalase, superoxide dismutase 2, peroxiredoxin 1 and peroxiredoxin 4) were increased in GBM. Protein–protein interaction analysis highlighted a reduction in multiple proteins coupled to energy metabolism (in particular respiratory chain proteins, including 23 complex-I proteins). Qualitative ultrastructural analysis in GBM with electron microscopy showed a notably higher prevalence of mitochondria with cristolysis in GBM. This study highlights the complex mitochondrial proteomic adjustments which occur in GBM pathophysiology

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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p

Proteomics approaches to fibrotic disorders

This review provides an introduction to mass spectrometry based proteomics and discusses several proteomics approaches that are relevant in understanding the pathophysiology of fibrotic disorders and the approaches that are frequently used in biomarker discovery

Oxidative stress augments toll-like receptor 8 mediated neutrophilic responses in healthy subjects

<p>Abstract</p> <p>Background</p> <p>Excessive oxidative stress has been reported to be generated in inflamed tissues and contribute to the pathogenesis of inflammatory lung diseases, exacerbations of which induced by viral infections are associated with toll-like receptor (TLR) activation. Among these receptors, TLR8 has been reported as a key receptor that recognizes single-strand RNA virus. However, it remains unknown whether TLR8 signaling is potentiated by oxidative stress. The aim of this study is to examine whether oxidative stress modulates TLR8 signaling in vitro.</p> <p>Methods</p> <p>Human peripheral blood neutrophils were obtained from healthy non-smokers and stimulated with TLR 7/8 agonist imidazoquinoline resiquimod (R848) in the presence or absence of hydrogen peroxide (H₂O₂). Neutrophilic responses including cytokine release, superoxide production and chemotaxis were examined, and the signal transduction was also analyzed.</p> <p>Results</p> <p>Activation of TLR8, but not TLR7, augmented IL-8 release. The R848-augmented IL-8 release was significantly potentiated by pretreatment with H₂O₂(p < 0.01), and N-acetyl-<smcaps>L</smcaps>-cysteine reversed this potentiation. The combination of H₂O₂and R848 significantly potentiated NF-kB phosphorylation and IkBα degradation. The H₂O₂-potentiated IL-8 release was suppressed by MG-132, a proteosome inhibitor, and by dexamethasone. The expressions of TLR8, myeloid differentiation primary response gene 88 (MyD88), and tumor necrosis factor receptor-associated factor 6 (TRAF6) were not affected by H₂O₂.</p> <p>Conclusion</p> <p>TLR8-mediated neutrophilic responses were markedly potentiated by oxidative stress, and the potentiation was mediated by enhanced NF-kB activation. These results suggest that oxidative stress might potentiate the neutrophilic inflammation during viral infection.</p

Non-specific interstitial pneumonia in cigarette smokers: a CT study

The goal of this study was to seek indirect evidence that smoking is an aetiological factor in some patients with non-specific interstitial pneumonia (NSIP). Ten current and eight ex-smokers with NSIP were compared to controls including 137 current smokers with no known interstitial lung disease and 11 non-smokers with NSIP. Prevalence and extent of emphysema in 18 smokers with NSIP were compared with subjects meeting GOLD criteria for chronic obstructive pulmonary disease (COPD; group A; n = 34) and healthy smokers (normal FEV1; group B; n = 103), respectively. Emphysema was present in 14/18 (77.8%) smokers with NSIP. Emphysema did not differ in prevalence between NSIP patients and group A controls (25/34, 73.5%), but was strikingly more prevalent in NSIP patients than in group B controls (18/103, 17.5%, P < 0.0005). On multiple logistic regression, the likelihood of emphysema increased when NSIP was present (OR = 18.8; 95% CI = 5.3–66.3; P < 0.0005) and with increasing age (OR = 1.04; 95% CI = 0.99–1.11; P = 0.08). Emphysema is as prevalent in smokers with NSIP as in smokers with COPD, and is strikingly more prevalent in these two groups than in healthy smoking controls. The association between NSIP and emphysema provides indirect support for a smoking pathogenesis hypothesis in some NSIP patients

Effects of long-term low-dose oxygen supplementation on the epithelial function, collagen metabolism and interstitial fibrogenesis in the guinea pig lung

<p>Abstract</p> <p>Background</p> <p>The patient population receiving long-term oxygen therapy has increased with the rising morbidity of COPD. Although high-dose oxygen induces pulmonary edema and interstitial fibrosis, potential lung injury caused by long-term exposure to low-dose oxygen has not been fully analyzed. This study was designed to clarify the effects of long-term low-dose oxygen inhalation on pulmonary epithelial function, edema formation, collagen metabolism, and alveolar fibrosis.</p> <p>Methods</p> <p>Guinea pigs (n = 159) were exposed to either 21% or 40% oxygen for a maximum of 16 weeks, and to 90% oxygen for a maximum of 120 hours. Clearance of inhaled technetium-labeled diethylene triamine pentaacetate (Tc-DTPA) and bronchoalveolar lavage fluid-to-serum ratio (BAL/Serum) of albumin (ALB) were used as markers of epithelial permeability. Lung wet-to-dry weight ratio (W/D) was measured to evaluate pulmonary edema, and types I and III collagenolytic activities and hydroxyproline content in the lung were analyzed as indices of collagen metabolism. Pulmonary fibrotic state was evaluated by histological quantification of fibrous tissue area stained with aniline blue.</p> <p>Results</p> <p>The clearance of Tc-DTPA was higher with 2 week exposure to 40% oxygen, while BAL/Serum Alb and W/D did not differ between the 40% and 21% groups. In the 40% oxygen group, type I collagenolytic activities at 2 and 4 weeks and type III collagenolytic activity at 2 weeks were increased. Hydroxyproline and fibrous tissue area were also increased at 2 weeks. No discernible injury was histologically observed in the 40% group, while progressive alveolar damage was observed in the 90% group.</p> <p>Conclusion</p> <p>These results indicate that epithelial function is damaged, collagen metabolism is affected, and both breakdown of collagen fibrils and fibrogenesis are transiently induced even with low-dose 40% oxygen exposure. However, these changes are successfully compensated even with continuous exposure to low-dose oxygen. We conclude that long-term low-dose oxygen exposure does not significantly induce permanent lung injury in guinea pigs.</p