Repression of cytochrome P450 by cytokines: IL-1 beta counteracts clofibric acid induction of CYP4A in cultured fetal rat hepatocytes

Disease-drug and drug-drug interaction in COVID-19: Risk and assessment

COVID-19 is announced as a global pandemic in 2020. Its mortality and morbidity rate are rapidly increasing, with limited medications. The emergent outbreak of COVID-19 prompted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) keeps spreading. In this infection, a patient's immune response plays pivotal role in the pathogenesis. This inflammatory factor was shown by its mediators that, in severe cases, reach the cytokine at peaks. Hyperinflammatory state may sparks significant imbalances in transporters and drug metabolic machinery, and subsequent alteration of drug pharmacokinetics may result in unexpected therapeutic response. The present scenario has accounted for the requirement for therapeutic opportunities to relive and overcome this pandemic. Despite the diminishing developments of COVID-19, there is no drug still approved to have significant effects with no side effect on the treatment for COVID-19 patients. Based on the evidence, many antiviral and anti-inflammatory drugs have been authorized by the Food and Drug Administration (FDA) to treat the COVID-19 patients even though not knowing the possible drug-drug interactions (DDI). Remdesivir, favipiravir, and molnupiravir are deemed the most hopeful antiviral agents by improving infected patient’s health. Dexamethasone is the first known steroid medicine that saved the lives of seriously ill patients. Some oligopeptides and proteins have also been using. The current review summarizes medication updates to treat COVID-19 patients in an inflammatory state and their interaction with drug transporters and drug-metabolizing enzymes. It gives an opinion on the potential DDI that may permit the individualization of these drugs, thereby enhancing the safety and efficacy.

Cytochrome P450-mediated drug interactions in COVID-19 patients: Current findings and possible mechanisms

At the end of 2019, the entire world has witnessed the birth of a new member of coronavirus family in Wuhan, China. Ever since, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has swiftly invaded every corner on the planet. By the end of April 2020, almost 3.5 million cases have been reported worldwide, with a death toll of about 250,000 deaths. It is currently well-recognized that patient’s immune response plays a pivotal role in the pathogenesis of Coronavirus Disease 2019 (COVID-19). This inflammatory element was evidenced by its elevated mediators that, in severe cases, reach their peak in a cytokine storm. Together with the reported markers of liver injury, such hyperinflammatory state may trigger significant derangements in hepatic cytochrome P450 metabolic machinery, and subsequent modulation of drug clearance that may result in unexpected therapeutic/toxic response. We hypothesize that COVID-19 patients are potentially vulnerable to a significant disease-drug interaction, and therefore, suitable dosing guidelines with therapeutic drug monitoring should be implemented to assure optimal clinical outcomes.

Expression of cytochrome P450 4A mRNA in mouse lung: effect of clofibrate and interleukin-1beta

Cytochromes P450 4A (CYP4A) metabolize arachidonic acid into hydroxyeicosatetraenoic acids (HETEs) that exhibit potent actions on airway smooth muscle tone. In the lung, modifications in CYP4A expression and HETEs production could thus contribute to alterations in airway reactivity. We characterized expression of CYP4A in the lung of BALB/c mice, and studied its regulation by the CYP4A inducer, clofibrate and by the pro-inflammatory and asthma-associated cytokine, interleukin-1beta (IL-1beta). Messenger RNA (mRNA) expression of Cyp4a10, 4a12 and 4a14 was assessed in lung from control and clofibrate or IL-1beta-treated mice using polymerase chain reaction after reverse transcription of total lung RNA. Cyp4a12 mRNA was the only Cyp4a mRNA detected in lung tissue from control mice, as well as mice treated with clofibrate or IL-1beta. In contrast, mRNA of all isoforms were found at significant levels in liver from control mice and at increased levels in liver from clofibrate-treated animals. Lung levels of Cyp4a12 mRNA were enhanced by ninefold in mice treated with clofibrate and by fourfold in animals injected with IL-1beta. In conclusion, Cyp4a12, but not Cyp4a10 or Cyp4a14, is expressed in the lung of BALB/c mice, and may be upregulated by clofibrate or IL-1beta. Since IL-1beta has been largely associated with asthma, our data suggest that CYP4A expression could be altered in asthmatic conditions and may thus contribute to changes in airway reactivity.

Enhanced induction of cytochrome P450 enzymes and CAR binding in TNF (p55(-/-)/p75(-/-)) double receptor knockout mice following phenobarbital treatment

Phenobarbital (PB) is a well characterized inducer of cytochrome P450 (P450) 2B and 3A subfamilies. Several proinflammatory cytokines have been shown to negatively modulate the induction of P450 by PB. In addition, PB is known to elicit an inflammatory mitogenic effect on the liver. To date, no studies have evaluated the PB induction profile of hepatic P450 in the absence of an intact tumor necrosis factor-alpha (TNFalpha) response. To test the hypothesis that endogenous TNFalpha signaling modulates hepatic P450 induction by PB in vivo, PB induction was examined in TNF (p55(-/-)/p75(-/-)) double receptor knockout mice (ko-TNF) and wild-type mice (wt-TNF). CYP2B- and CYP3A-associated activities and protein content were induced to a significantly greater extent (p < 0.05) in ko-TNF mice compared with wt-TNF mice. In parallel with enhanced CYP2B induction, an apparent elevation in the nuclear accumulation of the principal regulatory protein for transcription of CYP2B genes, the constitutively activated receptor (CAR), was detected in ko-TNF nuclear extracts following PB treatment. Additionally, nuclear factor kappa-B binding was induced by PB in wt-TNF mice, but not in ko-TNF mice, indicating that the hepatic inflammatory response following PB treatment differed between wt-TNF and ko-TNF mice. These data demonstrate that endogenous TNFalpha signaling modulates PB induction of hepatic CYP2B and CYP3A isoforms in vivo. Further, the data presented herein suggest that endogenous TNFalpha signaling influences PB induction of CYP2B through inhibition of CAR nuclear accumulation.

Cytochrome P450 and antioxidant activity in interleukin-6 knockout mice after induction of the acute-phase response

Hepatic cytochrome P450 (CYP) expression and antioxidant activity have been shown to decrease following endotoxin (lipopolysaccharide [LPS]) or proinflammatory cytokine administration. Using mice deficient in interleukin-6 (IL-6), the role of IL-6 in the regulation of hepatic CYP activity, glutathione (GSH) metabolism, and catalase (CAT) activity was analyzed after LPS administration. Administration of LPS produced comparable decreases in hepatic CYP3A activity in WT B6x129 (WT) mice and IL-6 knockout mice. No decrease was observed for CYP2D9 activity after LPS administration in either WT or IL-6 knockout mice. LPS administration significantly increased hepatic and renal CYP2E1 and CYP4A activity in WT mice, with no effect in IL-6 knockout mice. CYP2A12 activity increased in IL-6 knockout, mice with no change in WT mice after LPS administration. LPS administration had no significant effect on hepatic GSH reductase, GST peroxidase, GSH-S-transferase (GST), or total GSH in either WT or IL-6 knockout. However, hepatic CAT activity was significantly reduced in WT mice after LPS administration, with no effect in IL-6 knockout mice. These results support IL-6 as a critical mediator of the effects of LPS on specific hepatic and renal CYP activities and hepatic CAT activity.

The effectiveness of desensitization versus rechallenge treatment in HIV-positive patients with previous hypersensitivity to TMP-SMX: a randomized multicentric study. C.I.S.A.I. Group

Our study was undertaken to evaluate if desensitization treatment is more effective than rechallenge in preventing hypersensitivity reactions in HIV-positive patients with previous allergic reactions to TMP-SMX; the secondary aim was to evaluate the frequency of reactions to TMP alone. This was a randomized, multicentre open study. Patients with previous documented hypersensitivity to TMP-SMX who required primary or secondary PCP prophylaxis were enrolled; subjects who had previously had serious adverse reactions to TMP-SMX were excluded. All eligible patients assumed 200 mg TMP for 14 days and in case of no reactions were randomized for desensitization or rechallenge with TMP-SMX. The patients were then followed up by periodical visits for six months. Seventy-three patients were enrolled; 14 subjects (19%) presented reactions on TMP alone during the pre-enrollment phase. The remaining 59 subjects were randomly assigned to the two treatment groups: 34 carried out desensitization (group 1) and 25 rechallenge (group 2) with TMP-SMX. Seven patients in group 1 (20.5%) and seven in group 2 (28%) showed hypersensitivity reactions during treatment; this difference was not statistically significant. No serious reaction occurred in either group. This study showed the comparable effectiveness of the desensitization procedure and rechallenge in patients with a previous, not serious, allergic reaction to TMP-SMX.

Role of interleukin-1beta in the modulations of cytochrome P450 and heme metabolism in rat liver

The effect of recombinant human interleukin-1beta (IL-1beta) on the modulation of hepatic cytochrome P450 (P450) was investigated by in vivo subcutaneous dosing studies in male Sprague-Dawley rats. To assess the effect of IL-1beta on heme metabolism, we determined the delta-aminolevulinic acid synthetase (delta-ALAS) and heme oxygenase activities in the liver. IL-1beta suppressed the microsomal total P450 and heme contents and delta-ALAS activity in the liver. In contrast, microsomal heme oxygenase activity was significantly increased by the IL-1beta treatments. Western blot analysis and marker enzyme activities for individual P450 isoforms demonstrated that IL-1beta suppressed CYP2C6, 2C13, 2E1, and 3A2, whereas CYP2A, 2B1/2, 2C11, and 4A1 were not influenced by the treatments. IL-1beta inhibited both allylisopropylamide- and phenobarbital-inducible delta-ALAS activities in the liver. These results indicate that IL-1beta has differential effects on the constitutive P450, and also on delta-ALAS and heme oxygenase activities in rat liver. Thus, the modulation of hepatic P450 by IL-1beta is complex, and IL-1beta may be involved in the regulation of both apoprotein synthesis for each P450 isoform and the heme pools in the liver.

Regulation of cytochromes P450 during inflammation and infection

Hepatic P450 activities are profoundly affected by various infectious and inflammatory stimuli, and this has clinical and toxicological consequences. Whereas the expression of most P450s in the liver is suppressed, some are induced. Many of the effects observed in vivo can be mimicked by pro-inflammatory cytokines and IFNs, and P450s are differentially regulated by these agents. Therefore, different cytokine profiles and concentrations in the vicinity of the hepatocyte in different models of inflammation may result in qualitatively and quantitatively different effects on populations of P450s. In addition to cytokines, glucocorticoids may have an important role in P450 regulation in stress conditions, including that caused by inflammatory stimuli. Although in many cases the decreases in activity are due primarily to a down-regulation of P450 gene transcription, it is likely that modulation of RNA and protein turnover, as well as enzyme inhibition, contributes to some of the observed effects. The mechanisms whereby these effects are produced may also vary with both the P450 under study and the time course of the effect. The complexity of the P450 response to inflammation and infection means that all of the above factors must be considered when trying to predict the effect of a given infectious or inflammatory condition on the clinical or toxic response of humans or animals to an administered drug or toxin. The question of whether the down-regulation of the hepatic P450 system to inflammation or infection is a homeostatic or pathological response cannot be answered at present. It is difficult to discern the physiological benefit of reducing hepatic P450 activities, unless it is to prevent the generation of reactive oxygen species generated by uncoupled catalytic turnover of the enzymes. On the other hand, as we proposed some years ago [64], the suppression of P450 may be due to the liver's need to utilize its transcriptional machinery and energy for the synthesis of APPs involved in the inflammatory response. In that case, one could ask why the organism has gone to the trouble of employing differential mechanisms for suppression of P450. One answer could be that the response evolved after the divergence of many of the P450 genes, necessitating the evolution of multiple redundant mechanisms for P450 suppression. In contrast to the down-regulation of P450s in the liver, the induction of several forms in this and other tissues suggests a more specific homeostatic role of these effects, e.g., in generation or catabolism of bioactive metabolites.

Regulation of CYP4A1 and peroxisome proliferator-activated receptor alpha expression by interleukin-1beta, interleukin-6, and dexamethasone in cultured fetal rat hepatocytes

The CYP4A1 isoenzyme induced in rodents by peroxisome proliferators is known to be repressed at a pretranslational level by interferon. Interleukin-1beta (IL-1beta) also reduces CYP4A1-related 12-laurate hydroxylase activity in cultured fetal rat hepatocytes after induction by clofibric acid. In this fetal hepatocyte model, IL-1beta and interleukin-6 (IL-6) were tested for their ability to reduce 12-laurate hydroxylase activity, CYP4A1 apoprotein content, and the CYP4A1 mRNA level. IL-1beta and IL-6 strongly diminished CYP4A1 activity and apoprotein and mRNA levels in a dose- and time-dependent manner. CYP4A1 expression is thus down-regulated at a pretranslational level by these cytokines. As it has been shown that the peroxisome proliferator-activated receptor alpha (PPAR alpha) mediates the induction of the CYP4A1 gene by a peroxisome proliferator, the capacity of IL-1beta or IL-6 to modulate the PPAR alpha mRNA level was tested. It was found that IL-1beta and IL-6 both repress the induction of PPAR alpha expression exerted by the combined action of clofibric acid and dexamethasone. However, even at the highest concentration (10 ng/mL) tested for both cytokines, IL-1beta as well as IL-6 failed to abolish the induction of CYP4A1 by dexamethasone. The mechanism of the protective effect of the synthetic glucocorticoid on CYP4A1 repression by interleukins is discussed.

Interleukin 1 beta and interleukin 6 repress clofibric acid induction of different P450 isoforms in cultured foetal rat hepatocytes

1. Expression of various P450 subfamilies (1A, 2A, 2B, 2C, 3A) have been studied in cultured foetal rat hepatocytes after treatment with clofibric acid, a peroxisome proliferator and prototypic CYP4A inducer in vitro. Ethoxyresorufin O-deethylase activity (EROD, a CYP1A-related activity) as well as 7 alpha-, 16 alpha-, 2 alpha- and 6 beta-testosterone hydroxylase activities (CYP2A, 2B, 2C11 and 3A respectively) were determined during culture. Levels of the corresponding P450 apoproteins were measured by Western blotting. 2. Clofibric acid was able to induce all the P450-dependent activities studied. In most cases this induction required the additional presence of dexamethasone, an agent which promotes differentiation and favours long-term maintenance of the hepatocytes. 3. The major pro-inflammatory cytokines, IL-1 beta and IL-6, decrease the levels of the clofibric acid-induced P450 isoforms, except CYP1A, which was insensitive to IL-6, previous studies having shown that IL-1 beta represses lauric acid 12-hydroxylase activity after induction by clofibric acid. The effects of these cytokines were clearly dose- and time-dependent. The decrease in enzyme activity correlated with a decrease in apoprotein content. 4. The ability of clofibric acid to induce P450 isoforms highlights the complexity of P450 regulation by peroxisome proliferators. Our results confirm, moreover, that different P450 subfamilies are differentially affected by IL-1 beta and IL-6.

Immunostimulating lipopeptide, LtriP (RP 56142): comparison of the effect on hepatic cytochrome P 450 modulation and radioprotection in male and female of three mouse strains

The sex-dependent effect of lauroyl-L-Ala-D-gamma-Glu-L,L-A2pmNH2 (LtriP, RP 56142) on hepatic microsomal cytochromes P 450 (cyt P 450) was studied in three mouse strains NMRI, C3H/OuJ and C3H/HeJ. In NMRI and C3H/OuJ, strains which are responsive to bacterial lipopolysaccharides (LPS-responsive), regardless of the sex of the mouse, significant decrease in the amount of cyt P 450 was observed after LtriP treatment, with a concomitant reduction in ethoxyresorufin-O-deethylase (cyt P 450 1A-dependent) and 7-ethoxycoumarin-O-deethylase activities. This was not seen in C3H/HeJ (LPS-hyporesponsive) mice. These effects may be related to LtriP-dependent cytokine induction, since neither LtriP nor LPS stimulated interleukin-1 (IL-1) secretion by C3H/HeJ macrophages. 11- and 12-hydroxylations (11- and 12-OH) of lauric acid were compared in C3H/OuJ and C3H/HeJ mice. LtriP depressed the total enzymatic conversion of lauric acid in the two strains without modification of the 11/12-OH ratio for C3H/OuJ or male C3H/HeJ mice. However, in females C3H/HeJ mice this decrease was particularly significant and concerned especially the 12-OH activity (a marker of cyt P450 4A family). Although males of the three strains were more sensitive to irradiation than females, LtriP exerted a sex-independent radioprotection on NMRI and C3H/OuJ mice. Its radioprotective effect was illustrated by the preservation of all the enzymatic activities studied in treated NMRI mice, contrary to irradiated control animals. In contrast, for the C3H/HeJ strain, males were not protected by LtriP treatment and, furthermore, females showed a marked sensitization to irradiation. The effects in CH3/HeJ strain implicate LtriP in the control of cyt P 450 induction and of sensitivity to irradiation independently of IL-1 induction.

Interleukin-1 beta antagonizes phenobarbital induction of several major cytochromes P450 in adult rat hepatocytes in primary culture

We have investigated the effects of interleukin (IL)-1 beta and IL6 on expression and phenobarbital (PB) induction of ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-deethylase (PROD) activities, as well as on mRNA levels of cytochromes P450 (CYP) 1A, 2B, 2C, 2E and 3A, in rat hepatocytes in primary culture. IL6 slightly antagonized PB-induced PROD activity. Strikingly, IL1 beta strongly inhibited basal EROD and PROD activities, and fully blocked their induction by PB in a dose-dependent fashion. Furthermore IL1 beta completely suppressed PB induction of all CYP mRNAs analyzed. Our results demonstrate that IL1 beta can suppress basal CYP activities, as well as PB-inducible expression of five CYP mRNAs in rat hepatocytes in primary culture.