Cytochrome P450 3A4 Research Articles

Elucidating Contributions of Drug Transporters/Enzyme to Nonlinear Pharmacokinetics of Grazoprevir by PBPK Modeling With a Cluster Gauss-Newton Method.

Grazoprevir (GZR), a direct-acting agent for hepatitis C virus, is recognized as a substrate for organic anion transporting polypeptide 1B (OATP1B), cytochrome P450 3A (CYP3A), and P-glycoprotein (P-gp). The objective of the present study was to elucidate the contribution of these molecules to the nonlinear pharmacokinetics of GZR using a physiologically based pharmacokinetic (PBPK) model. Utilizing plasma concentration-time profiles of GZR derived from reported dose-escalation (50-800 mg) clinical studies and cumulative excretion data, around 10 parameters, including Michaelis constants (Km) for OATP1B, CYP3A, and P-gp, were estimated via a cluster Gauss-Newton method (CGNM). Parameter combinations that could reproduce the clinical data of GZR were obtained; however, discrepancies were noted between the invivo estimated Km and the corresponding invitro Km. Next, by incorporating the invitro Km values into our PBPK-CGNM analyses utilizing a penalized parameter method, newly obtained parameter combinations appropriately reflected both the invivo and invitro observations. Particularly regarding OATP1B, while saturation of uptake was not clearly observed in the invitro experiments without human serum albumin (HSA), Km values capable of explaining invivo saturation were obtained under physiological HSA concentrations. By estimating the extent of saturation for each molecule in the liver and intestine and conducting sensitivity analyses of the Km values, it was inferred that OATP1B3 contributed the most to the nonlinearity of plasma GZR concentrations, followed by P-gp. In conclusion, the PBPK-CGNM, supplemented by penalized invitro parameters, was shown to be effective for analyzing complex pharmacokinetics involving drug transporters and enzymes.

Clinical Assessment of the Drug-Drug Interaction Potential of Omaveloxolone in Healthy Adult Participants.

Omaveloxolone is approved in the United States and the European Union for the treatment of patients with Friedreich ataxia aged ≥16 years. It is mainly metabolized by cytochrome P450 (CYP) 3A4 in vitro. Two drug-drug interaction studies (NCT04008186 and NCT05909644) were performed to evaluate (1) the effect of drug-metabolizing enzymes (DMEs) and drug transporter (DT) modulators on the pharmacokinetics of omaveloxolone and (2) the effect of omaveloxolone on the pharmacokinetics of DME and DT substrates. Additionally, the safety of coadministering these drugs with omaveloxolone was assessed. Coadministration of the strong CYP3A4 inhibitor itraconazole significantly increased omaveloxolone maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC0-∞) by approximately 3- and 4-fold, respectively. Conversely, coadministration with the moderate CYP3A4 inducer efavirenz decreased Cmax and AUC0-∞ of omaveloxolone by 38.0% and 48.5%, respectively. Omaveloxolone exposure was also increased following coadministration with verapamil, a moderate CYP3A4 and P-glycoprotein (P-gp) inhibitor, but it was unaffected by the strong CYP2C8 inhibitor gemfibrozil. Coadministration of omaveloxolone reduced systemic exposure of the substrates of CYP3A4, CYP2C8, breast cancer resistance protein, and organic anion transporting polypeptide 1B1 but had no effect on those of P-gp and organic cation transporter 1. Omaveloxolone was well tolerated when administered alone and in combination with the DME and DT modulators or substrates. These findings support concomitant medication precautions and dosing recommendations for omaveloxolone when coadministered with a moderate or strong CYP3A4 inhibitor or inducer, as well as the substrates of certain CYP450 enzymesor transporters.

Stir-fried Semen Armeniacae Amarum Suppresses Aristolochic Acid I-Induced Nephrotoxicity and DNA Adducts.

To investigate the protective effects of stir-fried Semen Armeniacae Amarum (SAA) against aristolochic acid I (AAI)-induced nephrotoxicity and DNA adducts and elucidate the underlying mechanism involved for ensuring the safe use of Asari Radix et Rhizoma. In vitro, HEK293T cells overexpressing Flag-tagged multidrug resistance-associated protein 3 (MRP3) were constructed by Lentiviral transduction, and inhibitory effect of top 10 common pairs of medicinal herbs with Asari Radix et Rhizoma in clinic on MRP3 activity was verified using a self-constructed fluorescence screening system. The mRNA, protein expressions, and enzyme activity levels of NAD(P)H quinone dehydrogenase 1 (NQO1) and cytochrome P450 1A2 (CYP1A2) were measured in differentiated HepaRG cells. Hepatocyte toxicity after inhibition of AAI metabolite transport was detected using cell counting kit-8 assay. In vivo, C57BL/6 mice were randomly divided into 5 groups according to a random number table, including: control (1% sodium bicarbonate), AAI (10 mg/kg), stir-fried SAA (1.75 g/kg) and AAI + stir-fried SAA (1.75 and 8.75 g/kg) groups, 6 mice in each group. After 7 days of continuous gavage administration, liver and kidney damages were assessed, and the protein expressions and enzyme activity of liver metabolic enzymes NQO1 and CYP1A2 were determined simultaneously. In vivo, combination of 1.75 g/kg SAA and 10 mg/kg AAI suppressed AAI-induced nephrotoxicity and reduced dA-ALI formation by 26.7%, and these detoxification effects in a dose-dependent manner (P<0.01). Mechanistically, SAA inhibited MRP3 transport in vitro, downregulated NQO1 expression in vivo, increased CYP1A2 expression and enzymatic activity in vitro and in vivo, respectively (P<0.05 or P<0.01). Notably, SAA also reduced AAI-induced hepatotoxicity throughout the detoxification process, as indicated by a 41.3% reduction in the number of liver adducts (P<0.01). Stir-fried SAA is a novel drug candidate for the suppression of AAI-induced liver and kidney damages. The protective mechanism may be closely related to the regulation of transporters and metabolic enzymes.

Developmental Toxicity of Alkylated PAHs and Substituted Phenanthrenes: Structural Nuances Drive Diverse Toxicity and AHR activation

Polycyclic aromatic hydrocarbons (PAHs) are a diverse class of chemicals that occur in complex mixtures including parent and substituted PAHs. To understand the hazard posed by complex environmental PAH mixtures, we must first understand the structural drivers of activity and mode of action of individual PAHs. Understanding the toxicity of alkylated PAHs is important as they often occur in higher abundance in environmental matrices and can be more biologically active than their parent compounds. 104 alkylated PAHs were screened from 11 different parent compounds with emphasis on substituted phenanthrenes and their structurally dependent toxicity differences. Using a high-throughput early life stage zebrafish assay, embryos were exposed to concentrations between 0.1 to 100 μM and assessed for morphological and behavioral outcomes. The aryl hydrocarbon receptor (AHR) is often implicated in the toxicity of PAHs and the induction of cytochrome P4501A (cyp1a) is an excellent biomarker of Ahr activation. Embryos were evaluated for cyp1a induction using a fluorescence reporter line. Alkyl and polar phenanthrene derivatives were further assessed for spatial cyp1a expression and Ahr dependence of morphological effects. In the alkyl PAH screen 35 (33.7%) elicited a morphological or behavioral response and of those 23 (65%) also induced cyp1a. 31 (29.8%) of the chemicals only induced cyp1a. Toxicity varied substantially in response to substitution location, the amount of ring substitutions and alkyl chain length. Cyp1a induction varied by parent compound group and was a poor indicator of morphological or behavioral outcomes. Polar phenanthrenes were more biologically active than alkylated phenanthrene derivatives and their toxicity was not dependent upon the Ahr2, Ahr1a or Ahr1b when tested individually, despite cyp1a induction by 50% of polar phenanthrenes. Our results demonstrated that induction of cyp1a did not always correlate with PAH toxicity or Ahr dependence and that the type and location of phenanthrene substitution determined potency.

P-590. Impact of Pharmacoenhancers on the Pharmacokinetics and Safety of Lenacapavir in People with HIV

Abstract Background Lenacapavir (LEN) is approved for treatment of multidrug-resistant HIV-1 in combination with other antiretrovirals in heavily treatment-experienced (HTE) people with HIV (PWH). In the pivotal Phase 2/3 CAPELLA study (NCT04150068), participants (N=72) received oral LEN loading doses (Days 1 and 2: 600 mg; Day 8: 300 mg), followed by a 927 mg subcutaneous (SC) maintenance dose given every 6 months (Q6M) starting from Day 15. LEN is a substrate of P-gp (P-glycoprotein), CYP (Cytochrome P450) 3A and UGT (UDP-glucuronosyltransferase) 1A1; pharmacoenhancers/boosters such as cobicistat and ritonavir inhibit P-gp and CYP3A and are likely to affect LEN PK. As boosted protease inhibitors are commonly used in HTE PWH, we evaluated the impact of pharmacoenhancers on LEN PK and safety in PWH from the CAPELLA study.Figure 1:LEN Ctrough following (A) oral loading period (Day 15), and (B) SC injection (Week 26), with and without pharmacoenhancers Horizontal lines of the box represent the median with its interquartile, and error bars represent the range. Median values are indicated in individual plots. Methods Sparse PK samples were collected during the oral loading and the maintenance periods in the CAPELLA study. LEN plasma concentrations were summarized in participants receiving background regimens with or without pharmacoenhancers, at the end of oral loading period on Day 15 (N=45 and N=27; respectively) and at the end of first dosing interval at Week 26 (N=42 and N=30; respectively). Treatment emergent adverse events (AE) were assessed among participants receiving background regimens with or without pharmacoenhancers. Results Following oral loading of LEN (Days 1, 2 and 8), Day 15 median Ctrough were 61.1 and 27.0 ng/mL with and without pharmacoenhancers, respectively. Following SC dose on Day 15, median Ctrough at the end of Week 26 were 36.2 ng/mL and 24.7 ng/mL with and without pharmacoenhancers, respectively. The safety profile of LEN with or without pharmacoenhancers was generally similar (respectively: LEN-related AEs, 61.9% vs. 63.3%). Conclusion Pharmacoenhancers led to a modest increase in LEN exposure, which was not considered clinically relevant. The safety profile of LEN with or without pharmacoenhancers was similar. LEN can be coadministered with background regimens containing pharmacoenhancers without dose adjustment. Disclosures Vamshi Jogiraju, PhD, Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Naveed A. Shaik, PhD, Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Furong Wang, n/a, Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Hui Wang, PhD, Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Hadas Dvory-Sobol, PhD, Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Ramesh Palaparthy, PhD, Gilead Sciences, Inc.: 1475-US-PSP, 1475-WO-PCT, 1474-US-PSP, 1515-US-PSP, 1515-WO-PCT|Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Renu Singh, PhD, Gilead Sciences, Inc.: 1475-US-PSP, 1475-WO-PCT, 1474-US-PSP, 1515-US-PSP, 1515-WO-PCT|Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company)

P-1239. Systemic Exposure of Olorofim in Children with Invasive Fungal Infections

Abstract Background Olorofim (OLO) is a novel antifungal active vs. Aspergillus (including azole-resistant strains), resistant moulds (e.g., Lomentospora prolificans [LoPro]), and dimorphic moulds. Treatment with OLO in children with invasive fungal infection (IFI) is permitted under the Managed Access Program (MAP), where monitoring of trough concentrations is required due to sparsity of data in this population. Methods To be eligible for the MAP, children were aged 6 to 17 years, had an IFI infection that was shown to be or expected to be susceptible to OLO and had limited or no treatment options. Trough plasma samples (collected after an overnight fast) were sent to the central laboratory for analysis of OLO using a validated mass spectrometry assay. As a minimum, samples were taken after at least 7 days dosing and following any dose changes. The paediatric dose was informed by a population pharmacokinetic (PK) model built using PK data from 52 adult patients with IFI. This model was used to predict systemic exposure in children aged 6 to 17 years based on PK parameters adjusted by weight. Paediatric doses were chosen based on a goal of Cmin ≥ 0.1µg/mL in over 90% of population, whilst Cmax and AUC were to be kept as low as possible. A further dose adjustment was required if OLO was given with strong cytochrome P450 3A4 inhibitors or inducers. Results To date, 22 children have received OLO, aged 6 to 17 years (mean = 11.0 y), with body weights of 20 to 80 kg (mean = 37.4 kg). IFIs treated include: IA (7), LoPro (4), Scedosporium spp. (4), coccidiomycosis (2), and other rare fungi (5). Trough level data are available for 19 subjects; the predicted maintenance dose resulted in trough levels ≥ 0.1 µg/mL in 15 subjects (79%). For the remaining 4 subjects (21%) OLO dose was increased. After dose adjustment (if required), observed trough plasma concentrations exceeded the threshold needed for efficacy (i.e., &amp;gt; 0.1 µg/mL) on all sampling occasions. Conclusion With the relatively small population and sparse PK sampling data available, the predicted body-weight dependent doses for children aged 6 to 17 y are considered reasonable. The dose predictions will be updated as the PopPK model is refined and trough levels will continue to be monitored pending conduct of a formal paediatric study. Disclosures Karen Cornelissen, PhD, F2G: Stocks/Bonds (Private Company) John H. Rex, MD, F2G: Employee Daniela Zinzi, MD. Infectious Diseases Specialist, VP Clinical R&amp;D at F2G: Stocks/Bonds (Private Company) Roger Bruggemann, Pharm, PhD, F2G: Advisor/Consultant|F2G: Grant/Research Support|Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Mundipharma: Advisor/Consultant|Mundipharma: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support James Wright, n/a, F2G: Advisor/Consultant

An epigenetic memory at the CYP1A gene in cancer-resistant, pollution-adapted killifish

Human exposure to polycyclic aromatic hydrocarbons (PAH) is a significant public health problem that will worsen with a warming climate and increased large-scale wildfires. Here, we characterize an epigenetic memory at the cytochrome P450 1 A (CYP1A) gene in wild Fundulus heteroclitus that have adapted to chronic, extreme PAH pollution. In wild-type fish, CYP1A is highly induced by PAH. In PAH-tolerant fish, CYP1A induction is blunted. Since CYP1A metabolically activates PAH, this memory protects these fish from PAH-mediated cancer. However, PAH-tolerant fish reared in clean water recover CYP1A inducibility, indicating a non-genetic effect. We observed epigenetic control of this reversible memory of generational PAH stress in F1 PAH-tolerant embryos. We detected a bivalent domain in the CYP1A promoter enhancer comprising both activating and repressive histone post-translational modifications. Activating modifications, relative to repressive ones, showed greater increases in response to PAH in sensitive embryos, relative to tolerant, consistent with greater gene activation. PAH-tolerant adult fish showed persistent induction of CYP1A long after exposure cessation, which is consistent with defective CYP1A shutoff. These results indicate that PAH-tolerant fish have epigenetic protection against PAH-induced cancer in early life that degrades in response to continuous gene activation.

Effects of Environmentally Relevant Concentrations of Roundup on Oxidative-Nitrative Stress, Cellular Apoptosis, Prooxidant-Antioxidant Homeostasis, Renin andCYP1A Expressions in Goldfish: Molecular Mechanisms Underlying Kidney Damage During Roundup Exposure.

Roundup is one of the most widely used glyphosate-based harmful herbicides in the United States as well as globally, which poses a severe risk for terrestrial and aquatic organisms. In order to identify the detrimental effects of Roundup exposure in aquatic organisms, we investigated the environmentally relevant concentrations of Roundup exposure (low dose: 0.5 μg/L and high dose: 5.0 μg/L for 2 weeks) on renin expression, oxidative-nitrative stress biomarkers (e.g., 2,4-dinitrophenol, DNP; and 3-nitrotyrosine protein, NTP), prooxidant-antioxidant enzymes expressions (e.g., superoxide dismutase, SOD; and catalase, CAT), cellular apoptosis, and cytochrome P450 1A (CYP1A) mRNA levels in the kidneys of goldfish (Carassius auratus). Histopathological and in situ TUNEL analyses showed widespread tissue disruption (e.g., bowman's capsule shrinkage, melanin pigment formation, etc.) and induced apoptotic nuclei in the kidneys of goldfish. Immunohistochemical and quantitative real-time PCR (qRT-PCR) analyses showed a significant (p < 0.05) increase in the expression of renin, DNP, NTP, SOD, and CAT, as well as CYP1A mRNA levels in the kidneys of fish exposed to Roundup. These results suggest that environmentally relevant concentrations of Roundup disrupt kidney architecture by inducing oxidative-nitrative stress, cellular apoptosis, and change in osmoregulatory enzymes (i.e., renin) and prooxidant-antioxidant systems in the kidneys of teleost fishes.

Retraction Note: Association between cytochrome P4501A1 (CYP1A1) gene polymorphisms and the risk of renal cell carcinoma: a meta-analysis

Retraction Note: Association between cytochrome P4501A1 (CYP1A1) gene polymorphisms and the risk of renal cell carcinoma: a meta-analysis

Tolterodine is a novel candidate for assessing CYP3A4 activity through metabolic volatiles to predict drug responses

Cytochrome P450 (CYP) 3A4 plays a major role in drug metabolism. Its activity could be determined by non-invasive and cost-effective assays, such as breath analysis, for the personalised monitoring of drug response. For the first time, we identify an isotopically unlabelled CYP3A4 substrate, tolterodine that leads to the formation of a non-toxic volatile metabolite, acetone, which could potentially be applied to monitor CYP3A4 activity in humans. In vitro biotransformation of tolterodine by HepG2 cells overexpressing CYP3A4, CYP2D6 or CYP2C9 was investigated by LC-MS analysis of cell culture supernatant for the non-volatile metabolite, N-dealkylated tolterodine, and PTR-ToF-MS analysis of the headspace for acetone. The highest level of the N-dealkylated metabolite was produced by HepG2-CYP3A4. Concentration dependent effects of tolterodine were analysed, resulting in TC50 values of 414 µM and 375 µM for HepG2-CYP3A4 and reference cells, respectively. Acetone and N-dealkylated tolterodine levels increased continuously over 24 h in HepG2-CYP3A4. Treatment with either a pan-CYP inhibitor, 1-aminobenzotriazole, or a CYP3A4 inhibitor, ketoconazole, considerably reduced the production of both metabolites in HepG2-CYP3A4 cells. These findings pave the way for the further development of non-invasive breath tests using unlabelled precursors to determine CYP enzyme activity in individuals.

Safety, Tolerability, and Pharmacokinetics of a Novel Anti-obesity Agent, S-309309, in Healthy Adults with or Without Obesity.

Anti-obesity medications are recommended for patients who do not achieve and maintain weight loss despite lifestyle interventions. S-309309 is a novel oral inhibitor of monoacylglycerol O-acyltransferase 2 being developed as a treatment for obesity. The objective of the study was to investigate the safety, clinical pharmacology, pharmacokinetics and pharmacodynamic biomarker of S-309309. A phase I, single-center, two-part, randomized, double-blind, placebo-controlled study of S-309309 following oral administration of a single-ascending dose (part 1) and a multiple dose (part 2) in healthy adults with or without obesity was conducted. We also assessed the effect of food on the pharmacokinetics of S-309309 and the effect of S-309309 on electrocardiogram parameters, the pharmacokinetics of midazolam (a cytochrome P450 3A substrate), and the pharmacodynamic biomarker of monoacylglycerol O-acyltransferase 2 inhibition. In part 1 (N = 50), a single-ascending dose of S-309309 in healthy adults demonstrated dose proportionality and comparable exposure of S-309309 between the fasted and fed states. In part 2 (N = 24), no clinically meaningful difference was observed in the pharmacokinetics of multiple doses between healthy adults with or without obesity. S-309309 did not affect the pharmacokinetics of the cytochrome P450 3A substrate. The pharmacodynamic biomarker of monoacylglycerol O-acyltransferase 2 inhibition, dicarboxylic acid (18:1), was significantly increased after S-309309 administration in healthy adults with or without obesity. Overall, S-309309 demonstrated acceptable safety and tolerability without any serious adverse events or discontinuations because of adverse events, and did not have a clinically relevant effect on the heart rate or cardiac conduction. An effect on the placebo-corrected change-from-baseline corrected QT interval, corrected for heart rate using the Fridericia method, exceeding 10 ms can be excluded. S-309309 was well tolerated as single-dose (up to 300 mg) and multiple-dose (50 mg once daily for 14 days) oral administration. The pharmacokinetic characteristics remained unaffected by obesity and food intake. S-309309 did not affect the pharmacokinetics of the cytochrome P450 3A substrate. Overall, S-309309 had an acceptable safety profile and favorable pharmacokinetic and pharmacodynamic characteristics. NCT05247970, date of registration: 8 February, 2022.

A Drug-Drug Interaction Study of Mobocertinib and Midazolam, a Cytochrome P450 3A Substrate, in Patients With Advanced Non-Small Cell Lung Cancer.

Mobocertinib is a kinase inhibitor designed to selectively target epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations in non-small cell lung cancer. This drug-drug interaction study assessed the effect of multiple-dose administration of mobocertinib on the pharmacokinetics (PK) of midazolam, a sensitive cytochrome P450 3A substrate. Patients with locally advanced or metastatic non-small cell lung cancer refractory/intolerant to standard available therapy were enrolled. In Cycle 1 (Part A; PK cycle), a single 3-mg oral dose of midazolam was administered on Days 1 and 24, and a single 1-mg intravenous dose of midazolam was administered on Days 2 and 25. Mobocertinib 160mg once daily was administered orally on Days 3-30. After Cycle 1, patients could continue receiving mobocertinib in 28-day cycles in Part B of the study. The study objective was to characterize the effect of mobocertinib on the single oral- and intravenous-dose PK of midazolam. Safety and exploratory efficacy were also assessed. Twenty-six patients were enrolled, and 13 patients were PK-evaluable. Safety findings were consistent with the known safety profile of mobocertinib, and diarrhea was the only Grade 3 or higher treatment-related adverse event observed in more than 2 patients. Two of 16 patients with EGFR exon 20 insertion mutations were confirmed responders per investigator. Coadministration of mobocertinib decreased the area under the plasma concentration-time curve from time zero to infinity of oral and intravenous midazolam by approximately 32% and 16%, respectively (geometric least-squares mean ratios of 0.676 and 0.837, respectively).

The effect of the use of omeprazole versus famotidine on the kidney transplant function: a randomized controlled study

Tacrolimus is metabolized in the liver with the participation of cytochrome P450 isoforms 3A4 and 3A5 (CYP3A4, CYP3A5). Omeprazole, unlike famotidine, is a substrate and inhibitor of CYP2C19, CYP3A4, CYP3A5 enzymes. The aim of the study is to compare the effect of omeprazole and famotidine on the tacrolimus concentration and the kidney transplant function. A randomized study was conducted in 24 adult patients with stable kidney transplant function who received a standard triple immunosuppression regimen. Patients were assigned to the group I (n = 12) additionally receiving omeprazole (20 mg) or the group II (n = 12) receiving famotidine (20 mg). At the time of qualification and during follow-up visits, tacrolimus blood concentration and selected laboratory tests were performed. Statistical analysis was performed using the MedCalc system. The value of tacrolimus concentration in the blood increased after a year in the group I (7.27 ± 2.33 vs 9.20 ± 2.46 ng/mL, p = 0.0478). A reduction in tacrolimus dosage was observed after three years in the group I (3.56 ± 1.75 vs 2.78 ± 1.00 mg, p = 0.0440) and in the group II (2.72 ± 0.84 vs 2.10 ± 0.48 mg, p = 0.0051). There was significant difference in the percentage changes of glomerular filtration rate between the groups after 3 years of the study (− 5.56% vs 9.13%, p = 0.0343). Omeprazole significantly change the concentration of tacrolimus in the blood when administered together with tacrolimus after one year of observation. There was no effect of famotidine or omeprazole on the function of the kidney transplant. ClinicalTrials.gov identifier: NCT05061303.

Discovering the compatibility of Coptidis Rhizoma and Gardeniae Fructus in attenuating hepatotoxicity through the association rules analysis of related formula.

Gardenia jasminoides J. Ellis (Gardeniae Fructus, GF) is a widely used herbal medicine in many prescriptions. However, inappropriate application of GF may induce hepatotoxicity, which greatly challenges its clinical application. In the field of Traditional Chinese Medicine, the principle of "Compatibility for Toxicity Attenuation" is a pivotal concept. So far, the basis and mechanisms of compatibility with GF remain unclear. We aimed to investigate the toxicity attenuating effects and potential mechanisms of compatibility of Coptis chinensis Franch (Coptidis Rhizoma, CR) and GF in hepatotoxicity. Association rules analysis was performed in 817 GF-related formulas, and 49 associated items were selected, among which CR and GF were ranked in the top two. Network pharmacology was used to elucidate the potential mechanisms of combination of CR and GF in mitigating hepatotoxicity. Nine potential hepatotoxic components of GF and 14 active components of CR were focused on, and 9 common targets for CR and GF were identified. Further GO and KEGG analyses showed that the toxicity attenuating effect of CR on GF-induced hepatotoxicity may be closely correlated with inflammatory response, response to hypoxia, cancer signaling pathways, PI3K-Akt and HIF-1 signaling pathway. The in vitro results indicated that the combined use of CR and GF increased the viability of HepG2 cells. Furthermore, the in vivo data demonstrated that CR inhibited GF-induced increase in serum ALT and AST levels and pathological changes in the livers of KM mice. Besides, CR reduced the accumulation of ROS and MDA, inhibited the release of TNF-α and IL-6, while elevated GSH level in the mouse liver tissues. Finally, the molecular docking results indicated that the active components of CR had strong binding affinity with the monooxygenase cytochrome P450 3A4 (CYP3A4). CR combination restored the expression of CYP3A4 in the liver tissues of mice challenged with GF. Co-administration with CR effectively reduced GF-induced hepatotoxicity through alleviating oxidative damage, inflammatory response and enhancing CYP3A4 expression.

Dendrobium nobile Lindl. alkaloids improve lipid metabolism by increasing LDL uptake through regulation of the LXRα/IDOL/LDLR pathway and inhibition of PCSK9 expression in HepG2 cells.

Dendrobium nobile Lindl. alkaloids (DNLA) are active ingredients that can be extracted from the traditional Chinese herb Dendrobium Nobile Lindl. DNLA exhibits hypoglycemic and antihyperlipidemia effects. However, to the best of our knowledge, the specific molecular mechanism by which DNLA can regulate lipid metabolism remains unclear. The aim of the present study was to investigate the effect of DNLA on lipopolysaccharide (LPS)-induced lipid metabolism in HepG2 cells and its potential mechanism. HepG2 cells were treated with LPS with or without different concentrations of DNLA (0, 0.035, 0.35 and 3.5 µg/ml) for 48 h. Cell viability was then detected using the Cell Counting Kit-8 assay. The 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanideperchlorate-low-density lipoprotein (LDL) uptake assay was used to examine LDL uptake. In addition, possible mechanisms were explored using western blot analysis. The effect of the combination of DNLA with rosuvastatin calcium on the expression levels of the LDL receptor (LDLR) and proprotein convertase subtilisin/Kexin type 9 (PCSK9) was examined. The results indicated that LPS stimulation reduced the uptake of LDL by HepG2 cells, decreased the intracellular LDLR content, and increased the expression levels of inducible degrader of the LDLR (IDOL) and liver X receptor (LXR)α. DNLA intervention reversed all of the aforementioned LPS-induced effects in HepG2 cells. Additional mechanistic experiments revealed that DNLA exerted its effects mainly by regulating the LXRα/IDOL/LDLR pathway. It was shown that DNLA also reduced the expression levels of PCSK9, sterol regulatory element binding protein 2 and hepatocyte nuclear factor 1α. In addition, DNLA decreased the expression levels of PCSK9 in rosuvastatin calcium-induced HepG2 cells. Notably, DNLA was able to decrease 3-hydroxy-3-methylglutaryl-coenzyme A reductase and increase cytochrome p450 7A1 expression at the protein level, which are rate-limiting enzymes in cholesterol synthesis and metabolism. Collectively, these data suggested that DNLA could enhance LDL uptake of HepG2 cells by increasing LDLR expression through the LXRα/IDOL/LDLR pathway to alleviate the effects induced by LPS, suggesting the potential benefit of DNLA in improving lipid metabolism disorders.

Positioning Enzyme- and Transporter-Based Precipitant Drug-Drug Interaction Studies in Drug Design.

In vitro assessment of the potential of compounds to affect drug metabolizing enzymes and transporters and perpetrate drug-drug interactions (DDIs) is a common practice in drug research. For the development phase, regulators define an exhaustive list of enzymes and transporters to consider, but DDIs associated with many of these are minor and can be well-managed in the clinic; thus, progression of drug candidates that address unmet medical needs should not be curtailed due to this property. However, some enzymes and transporters are very important in drug disposition, so it is important to avoid/reduce inhibition or induction of these through drug design. Herein, simplified criteria and methodologies amenable to high-throughput screening are defined to enable drug design to address DDI risk. A strategy is proposed that focuses on the most important enzymes and transporters: namely, cytochrome P450 (CYP) 3A4, CYP2C9, and CYP2D6, organic anion transporting polypeptide (OATP) 1B1, and breast cancer resistant protein (BCRP).

Enhanced expression of Cyp17a1 and production of DHEA-S in the liver of late-pregnant rats.

Cytochrome P450 17A1 (CYP17A1) catalyzes two enzymatic reactions in the biosynthesis of dehydroepiandrosterone (DHEA) from pregnenolone. In pregnant humans, the adrenal gland is responsible for DHEA biosynthesis, which is then sulfated by SULT2A1 and released into the bloodstream. This sulfated DHEA is subsequently taken up by the placenta and deconjugated to serve as a precursor for estrogen biosynthesis. The expression of Cyp17a1 is regulated by methylation, typically showing marked interspecies differences, including repression of Cyp17a1 expression in the adrenal gland of rodents. This study focused on the liver, an extragonadal steroidogenic organ showing active sulfate conjugation, as a site for DHEA-sulfate (DHEA-S) biosynthesis during pregnancy in rodents, rather than the adrenal glands. Cyp17a1 expression in rat liver was significantly lower than in the testis, with no differences between sexes. However, Cyp17a1 expression increased significantly before parturition (gestational days [GD] 19-21) compared to late pregnancy (GD 15-18). The Sult2a family were expressed in the livers of both pregnant and non-pregnant rats. We also observed increased DHEA and DHEA-S levels in the liver of pregnant rats before parturition compared to non-pregnant rats, with DHEA-S concentrations being significantly higher at GD 19-21 than at days 15-18. These findings suggest that increased expression of Cyp17a1 in the last trimester enhances DHEA synthesis in the liver, and that DHEA is quickly conjugated by Sult2a. In rodents, the liver may be involved in DHEA-S biosynthesis before parturition, compensating for the repression of Cyp17a1 in the adrenal glands.

Mass Balance Recovery, Absorption, Metabolism, and Excretion of Elinzanetant in Healthy Human Volunteers and in vitro Biotransformation.

Elinzanetant is a dual neurokinin-1,3 receptor antagonist in development for the treatment of menopausal vasomotor symptoms. The objectives of these studies were to characterize the mass balance and biotransformation of elinzanetant. In the clinical evaluation, whole blood, plasma, urine, and feces were collected from healthy fasted male volunteers (n=6) following a single dose of 120 mg [14C]-elinzanetant oral suspension for analysis of total radioactivity and metabolite profiling. In vitro reaction phenotyping and kinetics experiments on enzymes involved in elinzanetant metabolism were performed. On average, 90.8% of the total radioactivity administered was recovered in excreta over 480 h, mostly via the fecal route (feces 90.4%; urine 0.4%). Elinzanetant was rapidly absorbed and extensively metabolized but remained the main circulating species in plasma, accounting for 39.1% of total radioactivity. Known principal and active metabolites M27, M30/34, and M18/21 accounted for 7.6%, 13.7%, and 4.9% of total radioactivity in plasma, respectively. All other radiolabeled plasma components were each < 3.5%, revealing the oxidation product M30/34 as the only metabolite with relevant exposure (> 10% of total radioactivity). In feces, metabolites resulting from oxidative biotransformation accounted, in sum, for ~ 40% of the dose, while elinzanetant remained the primary drug-related moiety. Results of in vitro experiments indicated that metabolism of elinzanetant was primarily mediated by cytochrome P450 3A4, with minor contribution from uridine 5'-diphospho-glucuronosyltransferase. Elinzanetant is metabolized mainly via oxidative biotransformation mediated by cytochrome P450 3A4, and primarily excreted in feces. The primary oxidation product M30/34 is a major human metabolite of elinzanetant. NCT04654897.

Dexlansoprazole is an aryl hydrocarbon receptor agonist.

Dexlansoprazole, a proton pump inhibitor, is commonly used to treat gastro-esophageal reflux disease and erosive esophagitis. The activated aryl hydrocarbon receptor (AhR) functions as a transcription factor by binding to the aryl hydrocarbon response element (AHRE) of its target genes, with cytochrome P450 (CYP) 1A1 being the most well-known target. In this study, we demonstrated that dexlansoprazole stimulates AhR activity, leading to increased CYP1A1 expression. Our findings indicate that treatment with 2μM dexlansoprazole is sufficient to induce CYP1A1 mRNA and protein expression, as well as AHRE-mediated transcriptional activity, in both human and mouse cells. Using AhR signal-deficient mutant cells and specific AhR antagonists-SR1, GNF351, and CH-223191-we confirmed that AhR is required for dexlansoprazole-induced CYP1A1 expression. Additionally, we showed that dexlansoprazole promotes AhR nuclear translocation, acting as an AhR agonist. However, due to its lower potency compared to FICZ and ITE in activating AhR, dexlansoprazole suppresses FICZ- and ITE-induced CYP1A1 expression in human liver HepG2 and ovarian granulosa HO23cell lines, suggesting that it functions as both an AhR agonist and a modulator. This study offers valuable insights into the potential clinical side effects of dexlansoprazole.

Catechin and quercitrin mitigate the cytotoxic effects of aflatoxin-B1 on liver and colon cells by inhibiting cytochrome P450 1A2 and 3A4, in silico

Catechin and quercitrin mitigate the cytotoxic effects of aflatoxin-B1 on liver and colon cells by inhibiting cytochrome P450 1A2 and 3A4, in silico