Human adenovirus modulates surfactant phospholipid trafficking

Area of Science:

• Pulmonary Medicine
• Cell Biology
• Virology

Background:

• Lung surfactant, rich in phosphatidylcholine (PC), is crucial for lung stability and secreted via apical pathways.
• Viral infections can disrupt normal cellular processes, potentially affecting lung function.

Purpose of the Study:

• To investigate how adenoviral infection alters surfactant phosphatidylcholine (PC) secretion in alveolar cells.
• To identify the specific mechanisms and cellular pathways involved in this disruption.

Main Methods:

• Utilized adenoviral infection models in cell cultures and examined PC secretion routes.
• Employed pharmacologic inhibitors and small interfering RNA (siRNA) targeting ATP-binding cassette (ABC) proteins, specifically ABCA1.
• Analyzed gene expression and protein levels, including ABCA1, in response to viral stimulation.

Main Results:

• Adenoviral infection inhibited apical surfactant PC secretion and induced basolateral export in alveolar cells.
• This basolateral export was dependent on the ATP-binding cassette transporter A1 (ABCA1) and was not observed with replication-deficient adenovirus.
• Adenovirus, via its E1A gene product, transcriptionally activated the ABCA1 gene, increasing ABCA1 levels.

Conclusions:

• Adenovirus disrupts lung surfactant homeostasis by hijacking the ABCA1 transporter to promote basolateral PC export.
• This redirection of PC limits the pool available for apical secretion, contributing to decreased surfactant levels.
• Identified a novel viral-mediated pathway for disrupting surfactant trafficking and lung stability.