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Published on: August 25, 2017
Lung development and susceptibility to chronic obstructive pulmonary disease
David Warburton1, Jack Gauldie, Saverio Bellusci
1Saban Research Institute Children's Hospital-Los Angeles, 4650 Sunset Blvd. #35, Los Angeles, CA 90027, USA. dwarburton@chla.usc.edu
Proceedings of the American Thoracic Society
|October 27, 2006
Summary
Genetic factors significantly influence emphysema development in smokers. Smad3 gene mutations in mice lead to early-onset emphysema, highlighting the role of matrix organization in lung disease.
Area of Science:
- Pulmonary Medicine
- Genetics
- Cell Biology
Background:
- Emphysema, a component of chronic obstructive pulmonary disease (COPD), is often viewed as age-related lung damage in smokers.
- However, genetic susceptibility plays a crucial role, as only a subset of smokers develop the condition, suggesting underlying genetic predispositions influence disease onset and progression.
Purpose of the Study:
- To investigate the genetic underpinnings of emphysema, focusing on the role of matrix organization and signaling pathways in lung development and disease.
- To explore the impact of genetic mutations on alveolar structure and the potential for therapeutic intervention using signaling pathways.
Main Methods:
- Utilized mouse models with genetic modifications (null mutation, hypomorphism, gain/loss of function) affecting key genes involved in matrix assembly and transforming growth factor-beta (TGF-β) signaling.
- Examined phenotypes including respiratory distress, alveolarization defects, and early-onset emphysema.
- Investigated the role of Smad3 gene and its downstream effects on matrix metalloproteinase-9 (MMP-9) activity.
- Assessed the impact of environmental factors like side-stream smoke exposure on disease severity in genetically modified mice.
Main Results:
- Genetic interference with matrix integrity genes (e.g., elastin, fibrillin) resulted in alveolar dysplasia.
- Smad3-null mice exhibited impaired alveolar matrix organization, leading to early-onset emphysema mediated by MMP-9.
- Exposure to side-stream smoke exacerbated alveolar destruction and accelerated emphysema in Smad3-null mice.
- Human studies show polymorphisms in fibrillin, TGF-β receptor type II, and MMP-9 genes are associated with emphysema.
Conclusions:
- Dysfunctional or degraded extracellular matrix disrupts the niche for alveolar stem/progenitor cells, impairing lung repair and contributing to emphysema.
- Genetic factors, particularly those affecting matrix organization and TGF-β signaling, are critical in the pathogenesis of emphysema.
- Targeting signaling pathways offers a potential therapeutic strategy to restore alveolar structure and function.
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