Ethanol-exposed lung fibroblasts cause airway epithelial barrier dysfunction.

Area of Science:

• Pulmonary Medicine
• Cell Biology
• Toxicology

Background:

• Chronic alcohol ingestion is linked to lung injury and impaired repair during sepsis.
• Alcohol disrupts epithelial barrier homeostasis by altering transforming growth factor-beta 1 (TGFβ1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) expression and signaling.
• Lung fibroblasts (LF) exposed to ethanol may contribute to altered airway epithelial barrier function.

Purpose of the Study:

• To investigate if ethanol-exposed lung fibroblasts (LF) dysregulate TGFβ1 and GM-CSF, impacting airway epithelial barrier function.
• To elucidate the role of TGFβ1 signaling in alcohol-induced lung injury.

Main Methods:

• Human or rat LF were cultured with or without ethanol and co-cultured with airway epithelial cells (AEC) on Transwell supports.
• Transepithelial electrical resistance (TER) was measured, and AEC were analyzed for tight junction protein (ZO-1) and mesenchymal protein expression.
• TGFβ1 and GM-CSF levels in conditioned media were quantified by ELISA; TGFβ1 activity was blocked using an inhibitor or neutralizing antibody.

Main Results:

• AEC co-cultured with ethanol-exposed LF (ELF) exhibited reduced TER and ZO-1 expression, with increased collagen type 1A1 and α-smooth muscle actin.
• ELF co-cultures showed increased activated TGFβ1 and decreased GM-CSF levels in conditioned media.
• Blocking TGFβ1 activity completely prevented the detrimental effects of ELF on AEC.

Conclusions:

• Ethanol-exposed LF induce airway epithelial barrier dysfunction in naive AEC through paracrine signaling.
• This dysfunction is mediated by TGFβ1 activation and GM-CSF suppression.
• These findings suggest a mechanism for alcohol-induced impairment of airway epithelial integrity, increasing susceptibility to lung injury.