Intracellular glutathione in stretch-induced cytokine release from alveolar type-2 like cells.
OBJECTIVE
Ventilator-induced lung injury (VILI) is characterized by release of inflammatory cytokines, but the mechanisms are not well understood. We hypothesized that stretch-induced cytokine production is dependent on oxidant release and is regulated by intracellular glutathione (GSH) inhibition of nuclear factor kappa B (NF-kappa B) and activator protein-1 (AP-1) binding.


METHODS
Type 2-like alveolar epithelial cells (A549) were exposed to cyclic stretch at 15% strain for 4 h at 20 cycles/min with or without N-acetylcysteine (NAC) or glutathione monoethylester (GSH-e) to increase intracellular GSH, or buthionine sulfoximine (BSO), to deplete intracellular GSH.


RESULTS
Cyclic stretch initially caused a decline in intracellular GSH and a rise in the levels of isoprostane, a marker of oxidant injury. This was followed by a significant increase in intracellular GSH and a decrease in isoprostane. Stretch-induced IL-8 and IL-6 production were significantly inhibited when intracellular GSH was further increased by NAC or GSH-e (P < 0.0001). Stretch-induced IL-8 and IL-6 production were augmented when intracellular GSH was depleted by BSO (P < 0.0001). NAC blocked stretch-induced NF-kappa B and AP-1 binding and inhibited IL-8 mRNA expression.


CONCLUSIONS
We conclude that oxidant release may play a role in lung cell stretch-induced cytokine release, and antioxidants, which increase intracellular GSH, may protect lung cells against stretch-induced injury.
Pulmonary & Critical Care Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
Behrouz
B
Jafari
Bin
B
Ouyang
Li-Fu
LF
Li
Charles A
CA
Hales
Deborah A
DA
Quinn
D000111:Acetylcysteine / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D015152:Blotting, Northern; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D028421:Isoprostanes / Q000378:metabolism; D015227:Lipid Peroxidation; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000378:metabolism; D013314:Stress, Mechanical; D018808:Transcription Factor AP-1 / Q000378:metabolism
D000975:Antioxidants; D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D028421:Isoprostanes; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D019328:Buthionine Sulfoximine; C042431:S-ethyl glutathione; D005978:Glutathione; D000111:Acetylcysteine