Angiotensin receptor blockade attenuates cigarette smoke-induced lung injury and rescues lung architecture in mice

Area of Science:

• Pulmonary Medicine
• Cellular Biology
• Pharmacology

Background:

• Chronic obstructive pulmonary disease (COPD) is a major smoking-related illness with no current disease-modifying treatments.
• Dysregulated transforming growth factor-beta (TGF-β) signaling is linked to lung pathology in COPD patients and animal models.
• Cigarette smoke (CS) exposure induces lung injury, including emphysema and fibrosis, associated with enhanced TGF-β signaling.

Purpose of the Study:

• To investigate the protective effects of inhibiting TGF-β signaling against CS-induced lung injury.
• To evaluate TGF-β signaling in mouse models and human COPD samples.
• To explore therapeutic strategies targeting TGF-β for COPD.

Main Methods:

• Chronic exposure of mice to cigarette smoke (CS).
• Assessment of TGF-β signaling in lung tissues from CS-exposed mice and COPD patients.
• Systemic administration of a TGF-β-specific neutralizing antibody.
• Treatment with losartan, an angiotensin receptor type 1 blocker.

Main Results:

• CS exposure induced TGF-β signaling, alveolar cell apoptosis, emphysema, and fibrosis in mice.
• TGF-β neutralization and losartan treatment attenuated CS-induced lung injury, normalized TGF-β signaling, and reduced apoptosis.
• Losartan also improved oxidative stress, inflammation, metalloprotease activation, and elastin remodeling.
• Both interventions improved lung architecture and mechanics in CS-exposed mice.

Conclusions:

• Inhibition of TGF-β signaling, particularly through angiotensin receptor blockade, can mitigate CS-induced lung injury in a murine model.
• These findings support TGF-β pathway modulation as a therapeutic strategy for COPD.
• The study provides a preclinical basis for developing novel TGF-β-targeted therapies for COPD.