Abstract
Ethanol renders the lung susceptible to acute lung injury in the setting of insults such as sepsis. The mechanisms mediating this effect are unknown, but activation of tissue remodeling is considered key to this process. We found that chronic ethanol ingestion in rats increased the expression of fibronectin, a matrix glycoprotein implicated in acute lung injury. In cultured NIH/3T3 cells and in primary rat and mouse lung fibroblasts, ethanol induced fibronectin mRNA and protein expression in a dose- and time-dependent fashion. The effect of ethanol was prevented by inhibitors of protein kinase C and mitogen-activated protein kinases and was associated with the phosphorylation and increased DNA binding of the transcription factor cAMP response element binding protein, followed by increased transcription of the fibronectin gene. Fibroblasts were found to express α7 nicotinic acetylcholine receptor (nAChR), and ethanol induction of fibronectin was abolished by α-bungarotoxin and methyllcaconitine, inhibitors of α7 nAChRs. However, ethanol was able to induce fibronectin mRNA and protein in primary lung fibroblasts isolated from α7 nAChR knockout mice. The ethanol-induced fibronectin response was dependent on ethanol metabolism since 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, abolished the effect and acetaldehyde induced it. These observations suggest that ethanol or ethanol metabolites stimulate lung fibroblasts to produce fibronectin by inducing specific signals transmitted via nAChRs independent of the α7-subunit, and this might represent a mechanism by which ethanol renders the lung susceptible to acute lung injury.
Original language | English (US) |
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Pages (from-to) | L975-L987 |
Journal | American Journal of Physiology - Lung Cellular and Molecular Physiology |
Volume | 288 |
Issue number | 5 32-5 |
DOIs | |
State | Published - May 2005 |
Externally published | Yes |
Keywords
- Camp response element binding protein
- Extracellular matrix
- Gene transcription
- Lung injury
- Nicotinic acetylcholine receptors
- Signal transduction
- Tissue remodeling
ASJC Scopus subject areas
- Physiology
- Pulmonary and Respiratory Medicine
- Physiology (medical)
- Cell Biology