2026/01/30 by Lidia Jiménez-García, Andrea Pérez-Montero, Sandra Herránz +8 · 1 voice
Medicine · #Asthma and respiratory diseases #Chronic Obstructive Pulmonary Disease (COPD) Research #Neonatal Respiratory Health Research
paper · doi:10.1093/ajrcmb/aanag003
openalex publication_date 2026/01/30 · openalex created_date 2026/02/07 · openalex updated_date 2026/07/22
The alternative reading frame (ARF) protein, encoded by the CDKN2A locus, is well-recognized for its role in tumor suppression. Emerging evidence has highlighted ARF as a critical regulator of innate immunity and inflammation, with links to increased susceptibility to cardiometabolic diseases. This study investigates the role of ARF in lung homeostasis and reveals that its deficiency in mice affects lipid metabolism and leads to pulmonary abnormalities resembling pulmonary alveolar proteinosis (PAP). ARF-deficient mice exhibited abnormal surfactant clearance, characterized by lipid and protein accumulation in the alveoli, foamy alveolar macrophages (AMs) with enlarged and vacuolated morphology, and increased bronchoalveolar lavage fluid turbidity. These changes were linked to disrupted surfactant homeostasis resulting from an imbalance between increased lipid uptake (via upregulation of scavenger receptors such as SR-A1 and CD36) and impaired lipid efflux, evidenced by reduced expression of the cholesterol transporter SR-BI. These mice also display reduced AM numbers, increased eosinophil and neutrophil infiltration, consistent with secondary PAP. Additionally, a distinctive chemokine and cytokine profile (elevated Ccl12, Ccl2, Cxcl1, and IL-10) was observed, which may be associated with type 2 immune responses and alternative AM polarization. Interestingly, ARF deficiency also appears to compromise AM maintenance through effects on self-renewal and survival. Pulmonary function tests revealed increased tissue elastance and damping, suggesting early-stage lung stiffness. Collectively, these findings highlight the essential role of ARF in lung homeostasis and lipid regulation, providing insights into its potential involvement in PAP pathogenesis.