Differential effects of cytokines on the inducible expression of CYP1A1, CYP1A2, and CYP3A4 in human hepatocytes in primary culture

Abstract

We have investigated the effect of cytokines, including interleukin-6 (Il-6), interleukin-la (Il-la), and tumor necrosis factor-alpha ("Fa), on the inducible expression of cytochrome P450s (CYP) CYPlA1, CYPlA2, and CYP3A4 in human hepatocytes in primary culture. The ability of these cultures to mimic the acute phase response when stimulated with cytokines was evaluated using immunoblotting to measure the production of albumin, ferritin, fibrinogen, and ceruloplasmin. The cytokines exhibited specific patterns of action on the production of these proteins. Albumin was depressed by all the cytokines. In contrast to 11-6 and Il-la, T " -a reduced the production of fibrinogen and ceruloplasmin but stimulated the production of ferritin. When cells were treated with the CYP inducer alone, large increases in the expression of CYPlAl and CYPlA2 by P-naphthoflavone and of CYP3A4 by rifampicin were observed at messenger RNA (mRNA) and protein levels, by ribonuclease protection and immunoblotting, respectively. When the cells were treated with the inducer plus cytokines, the induction of mRNA was greatly reduced. Again, specific patterns of action were revealed: 11-6 had the most potent effect on CYP3A4, whereas TNF-a was the most potent with CYPlA genes. In all cases, changes at the protein levels paralleled changes at the mRNA levels. In cells preinduced with P-naphthoflavone or rifampicin, the decay with time of the levels of the CYPlA2 or CYP3A4 proteins, after the removal of the inducer, was not affected by cytokines. We conclude that cytokines strongly repress the inducibility of CYPlAs and CYP3A4 genes at a transcriptional or a posttranscriptional level, but affect neither the rate of translation of CYP mFWAs nor the rate of degradation of the CYP proteins in these cultures. (HEPATOLOGY 1995; 221 143-1 153.) Abbreviations: CYP, cytochrome P450s; TNF-a, tumor necrosis factoralpha; 11-10, interleukin-1 alpha; mRNA, messenger RNA, cDNA, complementary DNA, NO, nitric oxide.From the 'INSERM U 128,

Downregulation of drug transport and metabolism in mice bearing extra-hepatic malignancies

“…In vitro studies in hepatoma cell lines illustrate the downregulation of Cyp3a11 exposed to the proinflammatory cytokines IL-6, IL-1b and TNF-a (Lee and Piquette-Miller, 2001;Sukhai et al, 2001). Furthermore, the inducible expression of CYP3A4 by rifampicin in human primary hepatocytes in culture is abrogated by the administration of IL-6, suggesting a central role of IL-6 in the repression of CYP3A (Muntane-Relat et al, 1995;Guillen et al, 1998). On administration of these cytokines to rodents, reproducible reductions of Cyp3a mRNA expression with IL-1b, TNF-a and especially IL-6 were observed (Ghezzi et al, 1986a, b;Ferrari et al, 1993).…”

Hepatic cytochrome P450 down-regulation during aseptic inflammation in the mouse is interleukin 6 dependent

“…7 Several comparative studies have shown that, in general, all tested inflammatory mediators caused CYP downregulation with more or less similar efficiency. [8][9][10] However, from these studies it is difficult to estimate the relevance of each cytokine within the inflammatory process. Thus, the aim of the present study was to investigate the role of IL-6 in the down-regulation of specific CYP isoforms during inflammation in vivo using IL-6 Ϫ/Ϫ mice and compare it with the behavior of extracellular and intracellular APPs.…”

“…5,6 During pathologic disorders leading to activation of the inflammatory acute-phase response, impairment of CYP metabolic activity and decrease in total hepatic CYP content have been described (reviewed in Morgan 7 ). In vitro studies using hepatocytes [8][9][10][11][12] as well as in vivo studies in humans 13,14 and rodents [15][16][17] have shown that cytokines released during inflammation, like interleukin 1 (IL-1), tumor necrosis factor ␣ (TNF-␣), IL-6, and interferon, can down-regulate hepatic CYP through a still not well-established mechanism leading to transcriptional inhibition of CYP genes. 9,18 Despite the fact that all cytokines examined cause a characteristic CYP repression, their relevance in vivo remains to be elucidated.…”

Acetaminophen hepatotoxicity in tumor necrosis factor/lymphotoxin-α gene knockout mice

“…In fact, TNF and other proinflammatory cytokines have been shown to downregulate CYPs. 38,[58][59][60] Three lines of evidence, however, strongly suggest that the rate and extent of APAP bioactivation were similar in wild-type and TNF/LT-␣-deficient mice. First, the microsomal activity of the major CYP form (CYP2E1) that catalyzes the formation of NAPQI and that of CYP1A2 were unaltered in the knockout mice.…”