Under conditions of innate immune system activation (i.e., inflammation), the functions of specific cytochrome P450 enzymes, other drug metabolizing enzymes (DMEs), and drug transporters (DTs) are altered in the liver, small intestine, lung, kidney, and central nervous system (CNS). Many of these effects are primarily manifest at the transcriptional/RNA level, leading to corresponding changes in protein levels and function. This not only leads to altered drug and xenobiotic toxicity and action in diseased humans, but also has importance for disease therapy with biologic drugs that target inflammatory mediators or their receptors. Major roles for proinflammatory cytokines such as interleukin‐6 (IL‐6), IL‐1β, and tumor necrosis factor‐α(TNFα) are inferred from the abilities of these agents to affect DMEs and DTs in cultured cells and in vivo , but the in vivo contributions of cytokines to regulation of these proteins in different inflammatory disease states is still poorly understood.

ABSTRACT:We reported previously that infection of C3H/HeOuJ (HeOu) mice with the murine intestinal pathogen Citrobacter rodentium caused a selective modulation of hepatic cytochrome P450 (P450) gene expression in the liver that was independent of the Toll-like receptor 4. However, HeOu mice are much more sensitive to the pathogenic effects of C. rodentium infection, and the P450 down-regulation was associated with significant morbidity in the animals. Here, we report that oral infection of C57BL/6 mice with C. rodentium, which produced only mild clinical signs and symptoms, produced very similar effects on hepatic P450 expression in this strain. As in HeOu mice, CYP4A mRNAs and proteins were among the most sensitive to down-regulation, whereas CYP4F18 was induced. CYP2D9 mRNA was also induced 8-to 9-fold in the C57BL/6 mice. The time course of P450 regulation followed that of colonic inflammation and bacterial colonization, peaking at 7 to 10 days after infection and returning to normal at 15 to 24 days as the infection resolved. These changes also correlated with the time course of significant elevations in the serum of the proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-␣, as well as of interferon-␥ and IL-2, with serum levels of IL-6 being markedly higher than those of the other cytokines. Intraperitoneal administration of C. rodentium produced a rapid down-regulation of P450 enzymes that was quantitatively and qualitatively different from that of oral infection, although CYP2D9 was induced in both models, suggesting that the effects of oral infection on the liver are not due to bacterial translocation.

After infection with Citrobacter rodentium, murine hepatic cytochrome P450 (P450) mRNAs are selectively regulated. Several serum proinflammatory cytokines are elevated, the most abundant being interleukin-6 (IL6). To elucidate the role of cytokines in the regulation of P450s during infection, we orally infected wild-type, IL6(Ϫ/Ϫ), or interferon-␥(Ϫ/Ϫ) [IFN␥(Ϫ/Ϫ)] female C57BL/6J mice with C. rodentium and analyzed hepatic P450 expression 7 days later. The majority of P450 mRNAs were equally affected by infection in each genotype, indicating that IL6 and IFN␥ are not the primary mediators of P450 downregulation in this disease model. The down-regulation of CYP3A11 and CYP3A13 and induction of CYP2D9 mRNAs were attenuated in the IL6(Ϫ/Ϫ) mice, suggesting a role of IL6 in the regulation of only these P450s. Similar evidence implicated IFN␥ in the regulation of CYP2D9, CYP2D22, CYP3A11, CYP3A25, and CYP4F18 mRNAs in C. rodentium infection and CYP2B9, CYP2D22, and CYP2E1 in the bacterial lipopolysaccharide model of inflammation. This is the first indication of an in vivo role for IFN␥ in hepatic P450 regulation in disease states. The deficiency of IL6 or IFN␥ affected serum levels of the other cytokines. Moreover, experiments in cultured hepatocytes demonstrated that tumor necrosis factor ␣ (TNF␣) is the most potent and efficacious of the cytokines tested in the regulation of murine P450 expression. It is therefore possible that part of the IFN␥(Ϫ/Ϫ) and IL6(Ϫ/Ϫ) phenotypes could be attributed to the reduced levels of TNF␣ and part of the IFN␥(Ϫ/Ϫ) phenotype could be caused by reduced levels of IL6.

The transcription and protein expression of many cytochrome P450 (P450) genes are down-regulated in animal models of inflammation and infection. We determined previously that hepatic P450 mRNAs are selectively regulated in a mouse model of enteropathogenic bacterial infection, and that this regulation was not dependent on the lipopolysaccharide (LPS) receptor protein toll-like receptor 4 (TLR4). In the dextran sulfate sodium (DSS) model of chemically-induced inflammatory bowel disease (IBD), the reduction in activities of several hepatic P450 enzymes were concluded to be partially dependent on LPS from commensal bacteria (Masubuchi Y and Horie T (2004) Drug Metab. Dispos. 32: 437–441). In the present study, we sought to determine whether colitis induced by LPS regulates hepatic P450 mRNA and protein expression similarly to infectious colitis, and to determine the role of TLR4 in the response to DSS colitis. The role of LPS in the response to DSS was further examined by comparison with the effects of injected LPS. We demonstrate that administration of DSS results in the down-regulation of multiple P450 enzymes in mouse liver. However, there are discernable differences in the pattern of P450 expression in the two models. Some effects of DSS-induced colitis are TLR4-dependent, and others are not. In contrast, the effects of injected LPS on hepatic P450 mRNA expression are entirely TLR4-dependent. Thus, our results indicate that the pattern of hepatic P450 expression, and the mechanism of regulation, during inflammation of the bowel depend on the etiology of the disease.

Inflammation and infection downregulate the activity and expression of cytochrome P450s (P450s) and other drug metabolizing enzymes (DMEs) involved in hepatic drug clearance. Schistosoma mansoni infection was reported to cause a downregulation of hepatic P450-dependent activities in mouse liver, but little is known about the specific enzymes affected or whether phase II DMEs are also affected. Here we describe the effect of murine schistosomiasis on the expression of hepatic P450s, NADPH-cytochrome P450 reductase (Cpr), phase II drug metabolizing enzymes, and nuclear receptors at 30 and 45 days postinfection (dpi). Although the hepatic expression of some of these genes was altered at 30 dpi, we observed substantial changes in the expression of the majority of P450 mRNAs and proteins measured, Cpr protein, as well as many of the UDP-glucuronosyltransferases and sulfotransferases at 45 dpi. S. mansoni infection also altered nuclear receptor expression, inducing mRNA levels at 30 dpi and depressing levels at 45 dpi. S. mansoni evoked a T helper 2 (Th2) inflammatory response at 45 dpi, as indicated by the induction of hepatic Th2 cytokine mRNAs [interleukins 4, 5, and 13], whereas the hepatic proinflammatory response was relatively weak. Thus, chronic schistosomiasis markedly and selectively alters the expression of multiple DMEs, which may be associated with Th2 cytokine release. This would represent a novel mechanism of DME regulation in disease states. These findings have important implications for drug testing in infected mice, whereas the relevance to humans with schistosomiasis needs to be determined.

Various disease models have been shown to alter hepatic drugmetabolizing enzyme (DME) and transporter expression and to induce cholestasis through altered enzyme and transporter expression. Previously, we detailed the regulation of hepatic DMEs during infectious colitis caused by Citrobacter rodentium infection. We hypothesized that this infection would also modulate hepatic drug transporter expression and key genes of bile acid (BA) synthesis and transport. Mice lacking Toll-like receptor 4 (TLR4), interleukin-6 (IL-6), or interferon-gamma (IFNg) and appropriate wild-type animals were orally infected with C. rodentium and sacrificed 7 days later. In two wild-type strains, drug transporter mRNA expression was significantly decreased by infection for Slc22a4, Slco1a1, Slco1a4, Slco2b1, and Abcc6, whereas the downregulation of Abcc2, Abcc3, and Abcc4 were strain-dependent. In contrast, mRNA expressions of Slco3a1 and Abcb1b were increased in a strain-dependent manner. Expression of Abcb11, Slc10a1, the two major hepatic BA transporters, and Cyp7a1, the rate-limiting enzyme of BA synthesis, was also significantly decreased in infected animals. None of the above effects were caused by bacterial lipopolysaccharide, since they still occurred in the absence of functional TLR4. The downregulation of Slc22a4 and Cyp7a1 was absent in IFNg-null mice, and the downregulation of Slco1a1 was abrogated in IL-6-null mice, indicating in vivo roles for these cytokines in transporter regulation. These data indicate that C. rodentium infection modulates hepatic drug processing through alteration of transporter expression as well as DMEs. Furthermore, this infection downregulates important genes of BA synthesis and transport and may increase the risk for cholestasis.

Background Given the central importance of anti-malarial drugs in the treatment of malaria, there is a need to understand the effect of Plasmodium infection on the broad spectrum of drug metabolizing enzymes. Previous studies have shown reduced clearance of quinine, a treatment for Plasmodium infection, in individuals with malaria. Methods The hepatic expression of a large panel of drug metabolizing enzymes was studied in the livers of mice infected with the AS strain of Plasmodium chabaudi chabaudi , a nonlethal parasite in most strains of mice with several features that model human Plasmodium infections. C57BL/6J mice were infected with P. chabaudi by intraperitoneal injection of infected erythrocytes and sacrificed at different times after infection. Relative hepatic mRNA levels of various drug metabolizing enzymes, cytokines and acute phase proteins were measured by reverse transcriptase-real time PCR. Relative levels of cytochrome P450 proteins were measured by Western blotting with IR-dye labelled antibodies. Pharmacokinetics of 5 prototypic cytochrome P450 substrate drugs were measured by cassette dosing and high-resolution liquid chromatography-mass spectrometry. The results were analysed by MANOVA and post hoc univariate analysis of variance. Results The great majority of enzyme mRNAs were down-regulated, with the greatest effects occurring at the peak of parasitaemia 8 days post infection. Protein levels of cytochrome P450 enzymes in the Cyp 2b, 2c, 2d, 2e, 3a and 4a subfamilies were also down-regulated. Several distinct groups differing in their temporal patterns of regulation were identified. The cassette dosing study revealed that at the peak of parasitaemia, the clearances of caffeine, bupropion, tolbutamide and midazolam were markedly reduced by 60–70%. Conclusions These findings in a model of uncomplicated human malaria suggest that changes in drug clearance in this condition may be of sufficient magnitude to cause significant alterations in exposure and response of anti-malarial drugs and co-medications. Electronic supplementary material The online version of this article (10.1186/s12936-019-2860-5) contains supplementary material, which is available to authorized users.

The organochlorine pesticide, methoxychlor (MXC), is metabolized in animals to phenolic monoand bis-demethylated metabolites (OH-MXC and HPTE respectively) that interact with estrogen receptors and may be endocrine disruptors. The phase II detoxication of these compounds will influence the duration of action of the estrogenic metabolites, but has not been investigated extensively. In this study, the glucuronidation and sulfonation of OH-MXC and HPTE were investigated in subcellular fractions of liver and intestine from untreated, MXC-treated and 3-methylcholanthrene (3-MC)-treated channel catfish, Ictalurus punctatus. MXC-treated fish were given i.p. injections of 2 mg MXC/kg daily for 6 days and sacrificed 24 hr after the last dose. The 3-MC treatment was a single 10 mg/kg i.p. dose 5 days prior to sacrifice. In hepatic microsomes from control fish, the V max value (mean ± S.D., n=4) for glucuronidation of OH-MXC was 270 ± 50 pmol/ min/mg protein, higher than found for HPTE (110 ± 20 pmol/min/mg protein). For each substrate, the V max values observed in intestinal microsomes were approximately twice those found in the liver. The K m values for OH-MXC and HPTE glucuronidation in control liver were not significantly different and were 0.32 ± 0.04 mM for OH-MXC and 0.26 ± 0.06 mM for HPTE. The K m for the co-substrate, UDPGA, was higher in liver (0.28 ± 0.09 mM) than intestine (0.04 ± 0.02 mM). Treatment with 3-MC but not MXC increased the V max for glucuronidation in liver and intestine. Glucuronidation was a more efficient pathway than sulfonation for both substrates, in both tissues. The V max values for sulfonation of OH-MXC and HPTE respectively in liver cytosol were 7 ± 3 and 17 ± 4 pmol/min/mg protein and in intestinal cytosol were 13 ± 3 and 30 ± 5 pmol/min/mg protein. Treatment with 3-MC but not MXC increased rates of sulfonation of OH-MXC and HPTE and the model substrate, 3-hydroxy-benzo(a)pyrene in both intestine and liver. Comparison of the kinetics of the conjugation pathways with those published for the demethylation of MXC showed that formation of the endocrine-active metabolites was more efficient than either conjugation pathway. Residues of OH-MXC and HPTE were detected in extracts of liver microsomes from MXC-treated fish. This work showed that although OH-MXC and HPTE could be eliminated by glucuronidation and sulfonation, the phase II pathways were less efficient than the phase I pathway leading to formation of these endocrine-active metabolites.