Endotoxin enhances liver alcohol dehydrogenase by action through upstream stimulatory factor but not by nuclear factor-kappa B

Abstract

Liver alcohol dehydrogenase (ADH) is increased by physiological stress and by chronic administration of growth hormone (GH). Endotoxin plays a role in the pathogenesis of alcoholic liver disease. The effect of lipopolysaccharide (LPS), the endotoxin component of Gram-negative bacteria, was determined on liver ADH. LPS given daily to rats for 3 days increased ADH mRNA, ADH protein, and ADH activity. Nuclear factor-kappaB (NF-kappaB) in the liver nuclear extracts bound to an oligonucleotide specifying region -226 to -194 of the ADH promoter, whereas upstream stimulatory factor (USF) was shown previously to bind to a more proximal site. LPS increased NF-kappaB and USF binding to the ADH promoter. The NF-kappaB (p65) and NF-kappaB (p50) expression vectors inhibited the transfected ADH promoter activity, which contrasts with the previously demonstrated stimulation by an USF expression vector. The binding activities of STAT5b and of C/EBPbeta, which mediate the effect of GH on ADH, were not changed or decreased, respectively, by LPS, indicating that GH plays no intermediary role in the effect of LPS. This study shows that LPS increases ADH and that this effect is mediated by increased binding of USF to the ADH promoter and not by NF-kappaB, which has an inhibitory action.