Down-regulation Of Cytochrome P450 Enzymes Research Articles

Inflammation-mediated drug interactions of olokizumab and cytochrome P450 activities in patients with rheumatoid arthritis.

In patients with rheumatoid arthritis (RA), interleukin (IL)-6 affects the activity of cytochrome P450 (CYP) enzymes. Treatment with anti-IL-6 therapy can reverse the IL-6-mediated downregulation of CYP enzymes, resulting in changes in plasma levels of CYP substrates. The primary objective of this study was to evaluate the impact of the IL-6 inhibitor olokizumab on the pharmacokinetics of CYP probe substrates in subjects with active RA. Seventeen patients with active RA were orally administered a phenotyping cocktail of midazolam (CYP3A4 substrate), omeprazole (CYP2C19 substrate), warfarin (CYP2C9 substrate) and caffeine (CYP1A2 substrate) alone and 2weeks after a single subcutaneous injection of 128 mg olokizumab. The pharmacokinetic parameters of each substrate were calculated using noncompartmental analysis. Sixteen of 17 enrolled patients received the complete doses of the cocktail drugs and olokizumab and were eligible for the pharmacokinetic evaluations. After single-dose administration of olokizumab, the exposure of midazolam and omeprazole decreased by 30-33% and 26-32%, respectively, compared to when the substrates were administered along via cocktail. In the presence of olokizumab, caffeine exposure increased by 19-23% compared to caffeine administration alone. There were no significant changes in S-warfarin exposure. In patients with active RA, olokizumab potentially reverses the IL-6-mediated suppression of CYP3A4 and CYP2C19. According to FDA guidance, olokizumab is considered a weak inducer of CYP3A4 and CYP2C19.

#2436 Genetic variability in rosuvastatin metabolism explains rhabdomyolysis and consequent acute renal failure

Abstract Background and Aims Low density lipoprotein cholesterol is an independent risk factor for atherosclerotic cardiovascular disease. Rosuvastatin is one of the most frequently prescribed statins and also one of the most frequent causes of rhabdomyolysis with consequent acute renal failure (ARF). Risk factors for statin induced rhabdomyolysis, i.e. the type of statin and its dose, patient's age, kidney and liver function, gender and concurrent treatment with cytochrome P450 (CYP) inhibitors, should be considered at the time of statin prescription. Single nucleotide polymorphisms (SNPs) in genes coding the transport proteins (SLCO1B1, ABCG2) and CYP2C9, catalysing rosuvastatin oxidation, may lead to decreased protein function leading to accumulation of plasma rosuvastatin which increases the risk of rhabdomyolysis. Herewith we present a case of a female patient admitted to our department due to rhabdomyolysis and ARF with the aim of alerting against uncritical high dose rosuvastatin prescribing and of pointing out the role of genetic variability in drug metabolizing enzymes and transporters (DMET) in rosuvastatin side effects. Method a 79-years old Caucasian woman admitted to our department due to rhabdomyolysis and ARF was genotyped for polymorphisms in DMET genes coding for CYP2C9 (rs1799853, rs1057910, rs28371686, rs28371685), SLCO1B1 (rs4149056, rs2306283) and ABCG2 (rs2231142) using competitive allele specific polymerase chain reaction (KASPar). Results Presented patient suffered from an acute myocardial infarction in October 2023. She was treated with percutaneous coronary intervention, antiaggregation therapy and hypolipidemic therapy (rosuvastatin 40 mg/ezetimibe 10 mg). Her creatinine was 55 μM (eGFR 61 ml/min) at the time of statin prescription. Several months later she was admitted septic with myoglobin >50.000 μg/L and creatinine approximately 1600 μM. Infection was treated with piperacillin/tazobactam. Myoglobin was removed with Theranova dialyzer. The patient was dismissed home two weeks later with creatinine 230 μM. As potential patient's risk factors for rhabdomyolysis we considered high dose of rosuvastatin, patient's higher age and slower rosuvastatin disposition due to SNPs in DMET. Sepsis may have been an additional contributory factor. Genotyping revealed polymorphisms in all three genes involved in rosuvastatin metabolism and transport: CYP2C9, SLCO1B1 and ABCG2 (Table 1). Two genotypes resulted in the phenotypes with slower rosuvastatin metabolism, probably leading to gradual accumulation of plasma rosuvastatin, which may have manifested in rhabdomyolysis that contributed to ARF. Heterozygous CYP2C9*2 and *3 carriers have, in comparison to the wild type carriers, approximately 30% and 80% slower rosuvastatin metabolism, respectively. Heterozygous ABCG2 c.421C>A carrier state may also contribute slightly to rosuvastatin accumulation. Furthermore, the potential interaction with inflammation should not be overlooked, as inflammation may have a major effect on drug metabolism and transport through downregulation of CYP enzymes as well as drug transporters. If genotypes of the respective DMET genes were known in advance, high dose rosuvastatin could have been avoided despite relatively good kidney function at the time of rosuvastatin prescription. Conclusion Statins should be prescribed with caution and their dose adapted to the risk factors that should always be checked for at the time of statin prescription. We recommend periodical surveillance of serum creatinine, eGFR, urine protein to creatinine ratio, liver tests, creatine kinase and myoglobin in patients treated with high dose statins. Furthermore, SLCO1B1, ABCG2 and CYP2C9 genotyping before rosuvastatin prescription would enable insight into its metabolism. Genotype information could lead to more cautious statin prescribing, especially in the presence of other factors, such as infection or concomitant drug treatment that may modify the activity of DMET. In the case of chronic kidney disease drug dosing should be appropriately adjusted in accordance with drug's Summary of product characteristics and KDIGO guidelines.

Okadaic Acid Activates JAK/STAT Signaling to Affect Xenobiotic Metabolism in HepaRG Cells.

Okadaic acid (OA) is a marine biotoxin that is produced by algae and accumulates in filter-feeding shellfish, through which it enters the human food chain, leading to diarrheic shellfish poisoning (DSP) after ingestion. Furthermore, additional effects of OA have been observed, such as cytotoxicity. Additionally, a strong downregulation of the expression of xenobiotic-metabolizing enzymes in the liver can be observed. The underlying mechanisms of this, however, remain to be examined. In this study, we investigated a possible underlying mechanism of the downregulation of cytochrome P450 (CYP) enzymes and the nuclear receptors pregnane X receptor (PXR) and retinoid-X-receptor alpha (RXRα) by OA through NF-κB and subsequent JAK/STAT activation in human HepaRG hepatocarcinoma cells. Our data suggest an activation of NF-κB signaling and subsequent expression and release of interleukins, which then activate JAK-dependent signaling and thus STAT3. Moreover, using the NF-κB inhibitors JSH-23 and Methysticin and the JAK inhibitors Decernotinib and Tofacitinib, we were also able to demonstrate a connection between OA-induced NF-κB and JAK signaling and the downregulation of CYP enzymes. Overall, we provide clear evidence that the effect of OA on the expression of CYP enzymes in HepaRG cells is regulated through NF-κB and subsequent JAK signaling.

In vitro CYP450 enzyme down-regulation by GLP-1/glucagon co-agonist does not translate to observed drug-drug interactions in the clinic.

NN1177 is a glucagon/glucagon-like peptide 1 receptor co-agonist investigated for chronic weight management and treatment of non-alcoholic steatohepatitis. Here, we show concentration-dependent down-regulation of cytochrome P450 enzymes using freshly isolated human hepatocytes treated with this linear 29-amino acid peptide. Notably, reductions in CYP3A4 mRNA expression (57.2-71.7%) and activity (18.5-51.5%) were observed with a clinically-relevant concentration of 100 nM NN1177. CYP1A2 and CYP2B6 were also affected, but to a lesser extent. Physiological-based pharmacokinetic modelling simulated effects on CYP3A4 and CYP1A2 probe substrates (midazolam and caffeine, respectively) and revealed potential safety concerns related to drug-drug interactions (DDIs). To investigate the clinical relevance of observed in vitro CYP down-regulation, a phase 1 clinical cocktail study was initiated to assess the DDI potential. The study enrolled 45 study participants (BMI 23.0-29.9 kg/m2) to receive a Cooperstown 5+1 cocktail (midazolam, caffeine, omeprazole, dextromethorphan, and S-warfarin/vitamin K) alone and following steady state NN1177 exposure. The analysis of pharmacokinetic profiles for the cocktail drugs showed no significant effect from the co-administration of NN1177 on AUC0-inf for midazolam or S-warfarin. Omeprazole, caffeine, and dextromethorphan generally displayed decreases in AUC0-inf and Cmax following NN1177 co-administration. Thus, the in vitro observations were not reflected in the clinic. These findings highlight remaining challenges associated with standard in vitro systems used to predict DDIs for peptide-based drugs as well as the complexity of DDI trial design for these modalities. Overall, there is an urgent need for better pre-clinical models to assess potential drug-drug interaction risks associated with therapeutic peptides during drug development. Significance Statement This study highlights significant challenges associated with assessing drug-drug interaction risks for therapeutic peptides using in vitro systems, since potential concerns identified by standard assays did not translate to the clinical setting. Further research is required to guide investigators involved in peptide-based drug development towards better non-clinical models in order to more accurately evaluate potential drug-drug interactions.

Molecular Pathological Differences in Global Gene Expression between Two Sustained Proliferative Lesions, Nodular Regenerative Hepatocellular Hyperplasia and Hepatocellular Adenoma, in Mice.

Long-term exposure to piperonyl butoxide (PBO) induces multiple nodular masses along with hepatocellular tumors in the liver of mice. The histopathological features of the nodules led to our diagnosis of nodular regenerative hepatocellular hyperplasia (NRH). However, because of the lack of data on the biological characteristics of NRH, whether this lesion is truly nonneoplastic remains unknown. In this study, the molecular characteristics of NRH were compared with those of hepatocellular adenoma (HCA) by global gene expression analysis. Six-week-old male ICR mice were fed a diet containing 6,000 ppm PBO for 43 weeks to induce NRH and HCA development. Complementary DNA microarray analysis was performed using messenger RNA extracted from NRH and HCA frozen sections collected by laser microdissection. Hierarchical cluster analysis showed that all NRH samples clustered together but were separate from the HCA cluster. Pathway analysis revealed activation of the cell cycle and Delta-Notch signaling in both lesions, but the latter was more upregulated in HCA. Downregulation of cytochrome p450 enzymes was observed in NRH, but not in HCA. These results imply that NRH differs from HCA in terms of not only morphological but also molecular characteristics.

Characterization of post-surgical alterations in the bile duct-cannulated rat

The bile duct-cannulated (BDC) rat is a standard animal model used in ADME experiments. The aim of this study was to investigate post-surgical alterations that are relevant to ADME investigations in BDC rats compared with sham- and non-operated animals.Water and food intake was reduced in the animals’ post-surgery. This led to a lower body weight in operated animals. In BDC animals, aspartate aminotransferase (AST) levels in plasma were transiently elevated and total bile acid levels were reduced. Alpha1-acid glycoprotein (AGP) in plasma and the concentration of bile components in bile were elevated. Histopathology showed inflammation in the area of the cannulation between the liver and the small intestine. A microarray-based gene expression and RTq-PCR analysis identified altered expression for several genes involved in drug disposition including the down-regulation of cytochrome P450 enzymes. This led to reduced cytochrome P450 content in the liver and lower metabolic activity in microsomes from BDC and sham-operated rats compared with naïve animals.The results of the study suggest that the post-surgical inflammation leads to physiological changes relevant for drug absorption and disposition. These alterations should be accounted for in the interpretation of ADME studies in BDC animals.

Inflammatory reactions and drug response: importance of cytochrome P450 and membrane transporters

Inflammatory reactions (IRs), both infectious and aseptic, downregulate numerous enzymes of cytochrome P450 (CYP) and ATP-binding cassette transporters. The mechanism involves proinflammatory cytokines and activation of transcription factors, nuclear factor-κB, CCAAT-enhancer-binding protein-β and c-myc, which bind to negative regulatory elements and/or impede the binding of nuclear receptors to promoter elements. Downregulation of CYP enzymes and transporters modulates the kinetics of a drug, resulting in increased plasma and tissue concentrations of the drug and enhanced effect and/or toxicity. Clinical trials have shown that IRs increase the risk of myocardial infarction and stroke. In this article, we speculate that IRs downregulate cardiac and vascular CYP enzymes (CYP2C8/9 and CYP2J2) responsible for the formation of vasorelaxant products. Patients with IRs should be advised that the risk of drug adverse effects and of cardiovascular diseases is increased; therefore, the benefit–risk ratio and use of drugs with narrow therapeutic index should be revaluated, as well as the conditions precipitating cardiovascular events.

Nitric Oxide‐Dependent Proteasomal Degradation of Cytochrome P450 2B Proteins

Inflammation and infection cause the down-regulation of cytochrome P450 enzymes in rodent and human hepatocytes. Although many of these effects are achieved via transcriptional suppression, we have found that CYP2B1 protein is rapidly down-regulated in primary cultures of rat hepatocytes by a NO-dependent mechanism that is independent of any transcriptional effects (Ferrari et al., 2001, Mol. Pharmacol. 60, 209-216). Here, we show that CYP2B proteins in primary rat hepatocyte cultures were suppressed more than 70% after 8hr treatment with interleukin-1 (IL-1β), in an NO-dependent manner. The calpain inhibtor E64-d or the lysosomal protease inhibitors NH4Cl and chloroquine did not attenuate the down-regulation of CYP2B by IL-1, but treatment with the proteasome inhibitors MG132, clasto-Lactacystin β-lactone, or gliotoxin each abolished this suppression under conditions in which NO production was not affected. However, CYP2C11 was not down-regulated by IL-1 treatment and was not affected by the treatments of lysosomal, calpain, and proteasome inhibitors. Treatment of cells for 24 h with the NO-donors 3,3-Bis(aminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18), S-nitrosoglutathione, and S-nitroso N-acetylpenicillamine (SNAP) also suppressed CYP2B proteins. Treatment of HeLa cells with 500 μM NOC-18 enhanced the ubiquitination of c-myc-tagged CYP2B at 6 hr. These data suggest that NO-dependent CYP2B down-regulation results from proteasomal degradation through the ubiquitination of CYP2B. (This research was supported by NIH Grant GM 069971)

Targeted down-regulation of cytochrome P450 enzymes for forage quality improvement in alfalfa (Medicago sativa L.).

Improving the digestibility of forages provides a means to enhance animal performance and protect the environment against excessive animal waste. Increased lignin content during maturity, and corresponding changes in lignin composition, correlate with decreased digestibility of forages. These relationships have yet to be investigated in isogenic systems. By targeting three specific cytochrome P450 enzymes of the lignin pathway for antisense down-regulation, we generated transgenic alfalfa lines with a range of differences in lignin content and composition. There was a strong negative relationship between lignin content and rumen digestibility, but no relationship between lignin composition and digestibility, in these transgenic lines. Models for genetic manipulation of forage digestibility based on the changes in lignin composition that increase paper-pulping efficiency in trees are therefore invalid. Down-regulation of 4-coumarate 3-hydroxylase provided the largest improvements in digestibility yet seen in a forage crop.

Modulation of cytochrome P450 by inflammation in astrocytes

Activation of systemic host defense mechanisms results in the down-regulation of cytochrome P450 enzymes in the liver. This occurs for various induced and constitutive isoforms of cytochrome P450 in response to cytokines such as IFNs, IL-1, IL-6, and TNF-α, which are produced during infection. Although the levels of cytochrome P450 in brain regions are low, the enzymes are regionally distributed and may play a critical role in the activation or degradation of drugs and chemicals in localized areas. If activation of the immune response in the CNS by LPS modulates the activity of cytochrome P450 forms in the brain, this may alter normal metabolic pathways or contribute to drug or chemical toxicity. This hypothesis was addressed by examining the effect of LPS on a major cytochrome P450 form in isolated astrocytes obtained from newborn rats. These cells were shown to express CYP1A1/2 when induced by dibenz[ a, h]anthracene (DBA) as determined by enzyme activity, immunohistochemistry, and Western blotting. The treatment of these cells with LPS significantly attenuated the activity of these enzymes but had no effect on CYP1A1/2 protein levels as determined by Western blotting. The lack of effect by detoxified LPS indicated the requirement of the lipid A region on LPS to stimulate this response. Pentoxifylline (PNTX) prevented the LPS evoked decrease in CYP1A1/2 activity suggesting that cytokine release was a required component of this effect in astrocytes. These results indicate that stimulation of the immune response by LPS in isolated astrocytes decreases CYP1A1/2 activity. The release of cytokines is implicated in this effect and thought to participate in the functional inhibition of the enzyme as no effect on CYP1A1/2 protein levels was observed.