Identification of a possible association between carbon tetrachloride-induced hepatotoxicity and interleukin-8 expression

Abstract

Hepatotoxicants can elicit liver damage by various mechanisms that can result in cell necrosis and death. The changes induced by these compounds can vary from gross alterations in DNA repair mechanisms, protein synthesis, and apoptosis, to more discrete changes in oxidative damage and lipid peroxidation. However, little is known of the changes in gene expression that are fundamental to the mechanisms of hepatotoxicity. We have used DNA microarray technology to identify gene transcription associated with the toxicity caused by the hepatotoxicant carbon tetrachloride. Labeled poly A+ RNA from cultured human hepatoma cells (HepG2) exposed to carbon tetrachloride for 8 hours was hybridized to a human microarray filter. We found that 47 different genes were either upregulated or downregulated more than 2‐fold by the hepatotoxicant compared with dimethyl formamide, a chemical that does not cause liver cell damage. The proinflammatory cytokine interleukin‐8 (IL‐8) was upregulated over 7‐fold compared with control on the array, and this was subsequently confirmed at 1 hour and 8 hours by Northern blot analyses. We also found that carbon tetrachloride caused a time‐dependent increase in interleukin‐8 protein release in HepG2 cells, which was paralleled by a decrease in cell viability. These data demonstrate that carbon tetrachloride causes a rapid increase in IL‐8 mRNA expression in HepG2 cells and that this increase correlates with a later and significant increase in the levels of interleukin‐8 protein. These results illustrate the potential of microarray technology in the identification of novel gene changes associated with toxic processes. © 2000 John Wiley & Sons, Inc. J Biochem Toxicol 14:283–290, 2000

In vitro assessment of hepatoprotective agents against damage induced by acetaminophen and CCl4

“…Cells exposed to these toxic agents lose cell viability, release liver enzymes into the culture medium, do not metabolize the tetrazolium salt, and exhibit significantly changed TAOxC and levels of MDA, SOD, and GSH [16, 26]. The in vitro liver damage caused by CCl 4 has been hypothesized to be caused by two different mechanisms, depending on the concentration used and the exposure time: a direct solvent effect of the molecule itself or an indirect effect through the generation of free radicals and subsequent lipid peroxidation [27].…”

Differential Induction of Apoptosis and Senescence by the DNA Methyltransferase Inhibitors 5-Azacytidine and 5-Aza-2′-Deoxycytidine in Solid Tumor Cells

“…2E). Interestingly, increased IL-8 expression has been described as a molecular marker for hepatotoxicity in HepG2 cells (26) as well as under various apoptotic conditions in other cell types (27,28). Hence, induction of IL-8 expression by 5-aza-CR could rather be explained as a sign of cytotoxicity than as an effect of cellular senescence.…”

Microvesicular Steatosis Induced by a Short Chain Fatty Acid: Effects on Mitochondrial Function and Correlation with Gene Expression

“…Several studies have shown that this technique can be used to identify the molecular events that underlie the mechanism(s) of toxicity of xenobiotics (Holden et al, 2000;Harries et al, 2001;Reilly et al, 2001;Waring et al, 2002). We have previously shown that compounds of differing chemical classes cluster by mechanism of toxicity in both in vivo (Bulera et al, 2001;Thomas et al, 2001;Waring et al, 2001b) and in in vitro systems (Burczynski et al, 2000;Waring et al, 2001a).…”