Background: Apoptosis has recently been proposed to contribute to the pathogenesis of emphysema.
Methods: In order to establish if cell fate plays a role even in end-stage disease we studied 16 lungs (9 smoking-associated and 7 alpha1antitrypsin (AAT)-deficiency emphysema) from patients who had undergone lung transplantations. Six unused donor lungs served as controls. Apoptosis was evaluated by TUNEL analysis, single-stranded DNA laddering, electron microscopy and cell proliferation by an immunohistochemical method (MIB1). The role of the transforming growth factor (TGF)-beta1 pathway was also investigated and correlated with epithelial cell turnover and with the severity of inflammatory cell infiltrate.
Results: The apoptotic index (AI) was significantly higher in emphysematous lungs compared to the control group (p < or = 0.01), particularly if only lungs with AAT-deficiency emphysema were considered (p < or = 0.01 vs p = 0.09). The proliferation index was similar in patients and controls (1.9 +/- 2.2 vs 1.7 +/- 1.1). An increased number of T lymphocytes was observed in AAT-deficiency lungs than smoking-related cases (p < or = 0.05). TGF-beta1 expression in the alveolar wall was higher in patients with smoking-associated emphysema than in cases with AAT-deficiency emphysema (p < or = 0.05). A positive correlation between TGF-betaRII and AI was observed only in the control group (p < or = 0.005, r2 = 0.8). A negative correlation was found between the TGF-beta pathway (particularly TGF-betaRII) and T lymphocytes infiltrate in smoking-related cases (p < or = 0.05, r2 = 0.99)
Conclusion: Our findings suggest that apoptosis of alveolar epithelial cells plays an important role even in end-stage emphysema particularly in AAT-deficiency disease. The TGFbeta-1 pathway does not seem to directly influence epithelial turnover in end-stage disease. Inflammatory cytokine different from TGF-beta1 may differently orchestrate cell fate in AAT and smoking-related emphysema types.
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http://dx.doi.org/10.1186/1465-9921-6-14 | DOI Listing |
Chest
January 2025
Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
Alpha-1-Antitrypsin (A1AT) deficiency is a common hereditary disorder associated with increased risk of developing chronic obstructive pulmonary disease (COPD). Many individuals with severe A1AT deficiency go undiagnosed, or are diagnosed late, and fail to benefit from disease-specific counseling and modifying care. Since the 2012 Canadian Thoracic Society (CTS) A1AT deficiency clinical practice guideline, new approaches to optimal diagnosis using modern genetic testing and studies of A1AT augmentation therapy have been published.
View Article and Find Full Text PDFRev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Ribosomes use multiple electrical forces to regulate new protein construction, to ensure efficient protein cotranslation, chaperoning, and folding. When these electrical regulatory forces are disrupted as in point charge mutations, specific disease occurs from aberrantly folded proteins. α1 antitrypsin deficiency is perhaps the best-known misfolded protein disease and is covered in some detail.
View Article and Find Full Text PDFCell Rep Med
January 2025
Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA. Electronic address:
Alpha-1 antitrypsin (AAT) deficiency (AATD) is a monogenic disease caused by misfolding of AAT variants resulting in gain-of-toxic aggregation in the liver and loss of monomer activity in the lung leading to chronic obstructive pulmonary disease (COPD). Using high-throughput screening, we discovered a bioactive natural product, phenethyl isothiocyanate (PEITC), highly enriched in cruciferous vegetables, including watercress and broccoli, which improves the level of monomer secretion and neutrophil elastase (NE) inhibitory activity of AAT-Z through the endoplasmic reticulum (ER) redox sensor protein disulfide isomerase (PDI) A4 (PDIA4). The intracellular polymer burden of AAT-Z can be managed by combination treatment of PEITC and an autophagy activator.
View Article and Find Full Text PDFIJTLD Open
January 2025
Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Padua, Italy.
FEBS J
January 2025
Physics, Department of Molecular and Translational Medicine, University of Brescia, Italy.
Neutrophil elastase (NE) is released by activated neutrophils during an inflammatory response and exerts proteolytic activity on elastin and other extracellular matrix components. This protease is rapidly inhibited by the plasma serine protease inhibitor alpha-1-antitrypsin (AAT), and the importance of this protective activity on lung tissue is highlighted by the development of early onset emphysema in individuals with AAT deficiency. As a serpin, AAT presents a surface-exposed reactive centre loop (RCL) whose sequence mirrors the target protease specificity.
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