Valles SL, Blanco AM, Azorin I, Guasch R, Pascual M, Gomez-Lechon MJ, Renau-Piqueras J, Guerri C. Chronic Ethanol Consumption Enhances Interleukin-1-Mediated Signal Transduction in Rat Liver and in Cultured Hepatocytes.
Alcohol Clin Exp Res 2003;
27:1979-86. [PMID:
14691386 DOI:
10.1097/01.alc.0000099261.87880.21]
[Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND
Interleukin-1 (IL-1) is a central mediator of the inflammatory process. Increased serum levels of IL-1 have been reported in alcoholics with liver damage, but it remains unknown whether chronic ethanol intake, in the presence or absence of lipopolysaccharide (LPS), activates IL-1 release and signaling in the hepatocyte.
METHODS
IL-1beta and IL-10 release, expression of their receptors (IL-1RI and IL-10R), and the IL-1RI signal transduction response were evaluated in livers and cultured hepatocytes from ethanol-fed or pair-fed rats exposed in vivo or in vitro to LPS, ethanol, or both.
RESULTS
Chronic ethanol intake increased both the serum levels of IL-1beta and IL-10 and the expression of IL-1RI, but not of IL-10R, in the liver microsomal fraction. In vivo LPS administration potentiated the ethanol-induced release of plasma cytokines. It is interesting to note that ethanol, either given in a single dose or chronically fed, stimulated IL-1beta and IL-10 release from cultured hepatocytes. Stimulation of hepatocytes with IL-1beta caused a higher activation of IL-1-associated kinase, extracellular receptor-activated kinases 1 and 2, and nuclear factor-kappaB (NF-kappaB) in hepatocytes from alcohol-fed animals than from controls. Furthermore, in the absence of any stimulation, hepatocytes from alcohol-fed animals showed an activation of both kinases, as well as an increase in NF-kappaB binding. Our results suggest the participation of the extracellular signal-regulated kinase (ERK)1/2 pathway in ethanol-induced NF-kappaB activation, because treatment with PD-98059, an ERK1/2 inhibitor, partially suppressed IL-1beta-induced NF-kappaB expression.
CONCLUSIONS
Chronic ethanol intake potentiates the action of the proinflammatory cytokine IL-1beta, enhancing the release and signaling response of IL-1beta in the hepatocyte, which in conjunction with other cytokines or LPS may exacerbate the inflammatory damage associated with alcoholic liver disease.
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