Cytochrome P450 3A4 Research Articles

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.

Population pharmacokinetic analysis of quizartinib in patients with newly diagnosed FLT3-internal-tandem-duplication-positive acute myeloid leukemia.

The population pharmacokinetics (PK) of quizartinib and its pharmacologically active metabolite AC886 have been previously described in healthy volunteers (HV) and relapsed/refractory (R/R) FLT3-internal-tandem-duplication-positive (FLT3-IDT-positive) acute myeloid leukemia (AML) patients receiving quizartinib monotherapy. In this analysis, we characterized the population PK of quizartinib and AC886 in newly diagnosed FLT3-ITD-positive AML patients receiving standard induction and consolidation chemotherapy as background treatment, using data from the Phase 3 QuANTUM-First trial and 12 earlier studies. Quizartinib PK were best described by a three-compartment model with sequential zero- and first-order absorption and first-order elimination. A two-compartment model with first-order metabolite formation and first-order elimination best fitted AC886 data. The PK of both moieties showed large interindividual variability (approximately 70% coefficient of variation for systemic clearances). The use of strong cytochrome P450 3A (CYP3A) inhibitors had the largest impact on exposure, increasing the steady-state area under the curve during the dosing interval (AUCss) by 1.8-fold. This is consistent with observations in HV and R/R AML patients and confirms the need for dose adjustments during coadministration. A novel finding in newly diagnosed AML patients was the phase-dependent change in steady-state quizartinib exposure: dose-normalized AUCss values were 0.6-fold during induction, similar during consolidation, and 1.4-fold during continuation compared to R/R AML patients receiving quizartinib monotherapy. The present analysis highlighted the comparison of quizartinib and AC886 PK between newly diagnosed AML patients and previously studied populations, informed dose modifications needed with strong CYP3A inhibitors, and supported the use of derived individual exposure metrics in separate exposure-response analyses.

Innovative Personalized Medicine for Immunosuppressive Drugs Based on Novel Control Theory of Pharmacokinetics

Tacrolimus is widely recognized as an anti-rejection agent due to its immunosuppressive characteristics. It binds to the immunophilin FK506-binding protein (FKBP) and thus to calcineurin, and inhibits its activity. Tacrolimus' therapeutic concentration range in blood is narrow, and its pharmacokinetics are highly variable among individuals. First, because tacrolimus primarily distributes to red blood cells (RBCs), anemia and blood transfusions can cause fluctuations in tacrolimus blood concentrations. Variations in blood tacrolimus concentration significantly correlated with variations in RBC count, hemoglobin level, and hematocrit value, but not with variations in white blood cell or platelet counts. Interestingly, FKBP played an important role in tacrolimus distribution to RBCs. The effects of intracellular and extracellular FKBP levels on RBC distribution of tacrolimus in circulating blood were substantial. Secondly, proteins affecting pharmacokinetics can differ at the genetic level in their expression and functional potency. Genetic polymorphisms that influence tacrolimus pharmacokinetics have been reported. A polymorphism in the gene encoding the metabolic enzyme cytochrome P450 (CYP) 3A5 is a particularly influential factor affecting tacrolimus pharmacokinetics in Japanese patients. CYP3A5 polymorphisms correlated with individual differences in tacrolimus blood concentration changes after starting continuous infusion in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. In addition, CYP3A5*3 polymorphism also correlated with differences in the frequency of acute graft-versus-host disease (GVHD) development in allogeneic HSCT recipients.

Deconvoluting zavegepant drug-drug interactions: A phase I study to evaluate the effects of rifampin and itraconazole on zavegepant pharmacokinetics.

Zavegepant is a calcitonin gene-related peptide receptor antagonist for acute migraine treatment. This Phase I, open-label, fixed-sequence study evaluated the effects of itraconazole (a strong cytochrome P450 3A4 [CYP3A4] and P-glycoprotein [P-gp] inhibitor) on the pharmacokinetics of intranasal/oral zavegepant and the effects of rifampin (a strong inducer of CYP3A4 and P-gp; and an inhibitor of organic anion transporting polypeptide 1B3 [OATP1B3]) on oral zavegepant in healthy participants. In the intranasal/oral zavegepant-itraconazole cohort, participants received a single 10-mg dose of zavegepant nasal spray on Day 1, followed by oral zavegepant (50 mg) on Day 3. Itraconazole 200 mg once daily was administered from Days 4 to 12. On Day 7 zavegepant nasal spray and on Day 11 oral zavegepant were coadministered with itraconazole. In the oral zavegepant-rifampin cohort, participants received oral zavegepant (100 mg) on Day 1, rifampin 600 mg once daily on Days 2-10, and rifampin with zavegepant on Day 11. No significant change in zavegepant exposure was observed following coadministration of itraconazole with zavegepant nasal spray. For oral zavegepant coadministered with itraconazole, the area under the curve from 0 to infinity (AUC0-inf) and the maximum observed concentration (Cmax) of oral zavegepant increased by 59% and 77%, respectively. For oral zavegepant coadministered with rifampin, the AUC0-inf and Cmax of oral zavegepant increased by approximately 2.3- and 2.2-fold, respectively. These results suggest that OATP1B3 and intestinal P-gp are the more prominent pathways, as opposed to CYP3A4, for a zavegepant drug-drug interaction. Coadministration of OATP1B3 inhibitors with zavegepant nasal spray should be avoided.

Epigenetic mechanisms mediate cytochrome P450 1A1 expression and lung endothelial injury caused by MRSA invitro and invivo.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of severe pneumonia and acute respiratory distress syndrome (ARDS). To advance our mechanistic understanding of this important pathogen, we characterized the effects of MRSA-induced epigenetic modification of histone 3 lysine 9 acetylation (H3K9ac), an activator of gene transcription, on lung endothelial cells (EC), a critical site of ARDS pathophysiology. Chromatin immunoprecipitation and sequencing (ChIP-seq) analysis revealed that MRSA induces H3K9ac in the promoter regions of multiple genes, with the highest ranked peak annotated to the CYP1A1 gene. Subsequent experiments confirm that MRSA increases CYP1A1 protein and mRNA expression, and its enzymatic activity in EC. Epigenetic inhibitors (C646, RVX-208) reduce MRSA-induced CYP1A1 expression and inflammatory responses, including cytokine release and adhesion molecule expression. Inhibition of the Aryl hydrocarbon receptor (Ahr), a known mediator of CYP1A1 expression, blocks MRSA-induced upregulation of CYP1A1 mRNA and protein expression, enzyme activity, and cytokine release. Reduction of CYP1A1 protein expression by siRNA or inhibition of its activity by rhapontigenin attenuated MRSA-induced EC permeability and inflammatory responses. In a mouse model of MRSA-induced acute lung injury (ALI), inhibition of CYP1A1 activity by rhapontigenin improved multiple indices of ALI, including bronchoalveolar lavage (BAL) protein concentration, cytokine levels, and markers of endothelial damage. Analysis of publicly available data suggests upregulation of CYP1A1 expression in ARDS patients compared to ICU controls. In summary, these studies provide new insights into MRSA-induced lung injury and identify a novel functional role for epigenetic upregulation of CYP1A1 in lung EC during ARDS pathogenesis.

Clinical and Physiologically Based Pharmacokinetic Model Evaluations of Adagrasib Drug-Drug Interactions.

Adagrasib is a potent, highly selective, orally available, small molecule, covalent inhibitor of G12C mutated KRAS. As both a substrate and strong inhibitor of cytochrome P450 (CYP) 3A4, adagrasib inhibits its own CYP3A4-mediated metabolism following multiple dosing, resulting in time-dependent drug-drug interaction (DDI) liabilities. A physiologically-based pharmacokinetic (PBPK) model was developed and verified using a combination of physicochemical, in vitro and clinical pharmacokinetic (PK) data from healthy volunteers and cancer patients. The PBPK model well-described the single and multiple-dose adagrasib PK data as well as DDI data with itraconazole, rifampin, midazolam, warfarin, dextromethorphan, and digoxin, with model predictions within 1.5-fold of the observed clinical data. The PBPK model was used to predict untested scenarios including the clinical victim and perpetrator DDI liabilities at the approved dosing regimen of 600 mg twice daily (b.i.d.) in cancer patients. Strong, moderate, and weak inhibitors of CYP3A4 are predicted to have a negligible effect on the steady-state exposure of adagrasib 600 mg b.i.d. resulting from the significant inactivation of CYP3A4 by adagrasib. Additionally, strong and moderate inducers of CYP3A4 are predicted to decrease adagrasib exposure by 68% and 22%, respectively. As a perpetrator, adagrasib 600 mg b.i.d. is predicted to be a strong inhibitor of CYP3A4, a moderate inhibitor of CYP2C9 and CYP2D6, and an inhibitor of P-glycoprotein (P-gp). These results successfully supported regulatory interactions with the United States Food and Drug Administration regarding dosing recommendations for when adagrasib is used concomitantly with other medications, supporting a range of label claims in lieu of clinical trials.

Impact of Missense Mutations on AFB1 Metabolism in Bovine Cytochrome P4503A Isoforms: A Computational Mutagenesis and Molecular Docking Analysis

Impact of Missense Mutations on AFB1 Metabolism in Bovine Cytochrome P4503A Isoforms: A Computational Mutagenesis and Molecular Docking Analysis

Therapeutic effects of melatonin on the lungs of rats exposed to passive smoking

BackgroundPassive smoke has a significant impact on lung function and constitutes a critical public health issue, as smoking generates free radicals that damage the lungs and other tissues. Currently, limited research exists on whether the antioxidant melatonin can mitigate lung damage caused by smoking. This study aims to investigate the mechanisms through which melatonin alleviates acute lung disease induced by passive smoking.MethodsRats were divided into five groups (n = 6): a control group and three groups exposed to low, medium, and high concentrations of smoke, and a melatonin treatment group.ResultsData indicated that in the high concentration passive smoking group, the alveolar structure of the lung tissue was destroyed, and the total antioxidant capacity in lung tissue diminished as the concentration of smoke increased. The expressions of TNF-α, IL-6, and IL-1β exhibited similar results. The anti-apoptotic factors Bcl-2 and Bcl-xL mRNA level significantly decreased in the high concentration smoking group, while no significant changes were observed in the medium and low concentration groups. Conversely, the high concentration passive smoking increased the pro-apoptotic factors Bax and Caspase-3 mRNA levels. Additionally, endogenous melatonin levels in lung tissue gradually decreased following exposure to smoke, whereas the exogenous melatonin alleviated the changes in inflammatory factors and apoptosis-related factors in lung tissue. Furthermore, at high smoking concentrations, the mRNA levels of lung cancer-related genes vascular endothelial growth factor (VEGF), cytochromeP450 1A1 (CYP1A1), and cytochrome P450 1B1 (CYP1B1) were significantly increased, while exogenous melatonin reduced the expression of these genes in lung tissue.ConclusionsThese findings suggest that melatonin can diminish lung tissue damage, apoptosis, and inflammatory responses induced by passive smoking, as well as decrease the expression of lung cancer-related genes. Further experimental investigations involving exogenous melatonin treatments will be needed.

Synthesis and Characterization of Chiral Impurities of Mirabegron, Used as an Overactive Bladder Drug

Mirabegron is used to treat overactive bladder that drug substance is the first β3-adrenoreceptor (AR) agonist. The mechanism of action of Mirabegron is as an adrenergic beta-3-Agonist and cytochrome P450 3A inhibitor, and p-Glycoprotein inhibitor. This molecule is optical active and having one chiral center and only (R)-Mirabegron presents pharmacological activity being (S)-Mirabegron an impurity which critical to control. During the process development of Mirabegron, the chiral impurity of drug substance is challenging and also challenging to all pharmaceutical industries too, the opposite isomeric impurity is introduced form its key starting material and it follows the same reaction mechanism path up to final drug substance, present work describe the synthesis of chiral impurities of each intermediate, including key starting material and its drug substance and their characterization by spectral data (MS,1H-NMR and 13C-NMR). This work will help quality control (QC) to identify and control these impurities in the Mirabegron drug substance as per ICH guideline.

20-Hydroxyeicosatetraenoic Acid Regulates the Src/EGFR/NF-κB Signaling Pathway Via GPR75 to Activate Microglia and Promote TBI in the Immature Brain.

20-Hydroxyeicosatetraenoic acid (20-HETE) is associated with secondary damage in traumatic brain injury (TBI) of the immature brain. Microglial activation is pivotal in this process. However, the underlying mechanism of action remains unknown. While 20-HETE interacts with G protein-coupled receptor 75 (GPR75) in some pathological processes, their interaction in brain tissue remains uncertain. This study aimed to investigate whether 20-HETE can activate microglia by binding to GPR75 in TBI of the immature brain. Drug affinity responsive molecular target stability (DARTS) assays, cycloheximide (CHX) chase assays, and auto-dock assays were employed to analyze the interaction between 20-HETE and GPR75. The expression levels of cytochrome P450 4A (CYP4A) and GPR75 in activated microglia in an immature brain TBI model were observed by western blot and multiple immunofluorescence staining. The effects of different levels of 20-HETE expression and lentivirus-mediated GPR75 gene silencing on 20-HETE-induced inflammatory factor release from BV-2 cells were observed by enzyme-linked immunoassay (ELISA). The phosphorylation levels of the downstream Src kinase, epidermal growth factor receptor (EGFR), and nuclear factor (NF)-κB were assessed using western blot. Cell viability and apoptosis were detected by CCK-8 and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays. 20-HETE bound to the GPR75 protein and inhibited its degradation. GPR75 gene silencing reversed the 20-HETE-induced inflammatory activation of BV-2 cells, effectively inhibiting the activation of the Src/EGFR/NF-κB pathway and the effects of 20-HETE on cell viability and the apoptosis rate. In contrast, overexpression of GPR75 had the opposite effect. In addition, after immature brain TBI, the 20-HETE and GPR75 expression levels were upregulated in microglia, with significant activation of the Src/EGFR/NF-κB pathway. Inhibition of 20-HETE synthesis with N-hydroxy-N'-(4-n-butyl-2-methylphenyl) formamidine (HET0016) produced the opposite effect. 20-HETE regulates the Src/EGFR/NF-κB signaling pathway via GPR75 to activate microglia, promoting immature brain TBI. These findings offer a novel target for promoting the brain injury effect of 20-HETE.

Pre-ADMET studies of 5-(3',4'-dihydroxyphenyl)-γ-valerolactone, the bioactive intestinal metabolite of proanthocyanidins.

5-(3',4'-Dihydroxyphenyl)-γ-valerolactone (VL) is a bioactive metabolite resulting from the gut microbial metabolism of proanthocyanidins and flavonoids, known for its health-promoting effects, including antidiabetic and anti-inflammatory activities. Although VL has been observed in different in vivo studies, its pre-absorption, distribution, metabolism, excretion, toxicity (ADMET)properties have rarely been investigated. This study aims to address this gap by evaluating the pre-ADMET properties of VL for the first time. Also, the understanding of these properties is significant for correlating the encountered activities to this metabolite. In vitro absorption studies revealed that VL is rapidly metabolized and absorbed as its sulfate phase II conjugate (valerolactone sulfate), which enters systemic circulation and mildly activates the Breast Cancer Resistance Protein efflux transporter. In human S9 liver fraction, a mixture of liver enzymes used to simulate in vivo liver metabolism, VL is metabolized into glucuronic phase II conjugates (valerolactone glucuronide 1 [VLG1] and 2 [VLG2]) with a half-life of 8.72 min and an 80% conversion rate. In human liver microsomes, VL is metabolized at a slower rate (half-life of 23.08 min), suggesting that oxidative metabolism is secondary. Additionally, VL did not activate the pregnane X receptor or inhibit Cytochrome P3A4 (CYP3A4) and Cytochrome P1A2(CYP1A2) enzymes, indicating no risk of herb-drug interactions with coadministered prescription drugs.

The Effect of Metformin and Hydrochlorothiazide on Cytochrome P450 3A4 Metabolism of Ivermectin: Insights from In Silico Experimentation.

The spread of SARS-CoV-2 has led to an interest in using ivermectin (a potent antiparasitic agent) as an antiviral agent despite the lack of convincing in vivo clinical data for its use against COVID-19. The off-target prophylactic use of ivermectin adds a substantial risk of drug-drug interactions with pharmaceutical medications used to treat chronic conditions like diabetes and hypertension (metformin and hydrochlorothiazide, respectively). Therefore, this study aims to evaluate the potential drug-drug interactions between ivermectin with either metformin or hydrochlorothiazide. In silico experiments and high-throughput screening assays for CYP3A4 were conducted to understand how metformin and hydrochlorothiazide might affect CYP3A4's role in metabolizing ivermectin. The study findings indicated that hydrochlorothiazide is more stable than both ivermectin and metformin. This conclusion was further supported by root mean square fluctuation analysis, which showed that hydrochlorothiazide is more flexible. The variation in the principal component analysis scatter plot across the first three normal modes suggests hydrochlorothiazide has a more mobile conformation than ivermectin and metformin. Additionally, a strong inhibition of CYP3A4 by hydrochlorothiazide was observed, suggesting that hydrochlorothiazide's regulatory effects could significantly impede CYP3A4 activity, potentially leading to a reduced metabolism and clearance of ivermectin in the body. Concurrent administration of these drugs may result in drug-drug interactions and hinder the hepatic metabolism of ivermectin.

Bacterial expression, purification, and characterization of human cytochrome P450 3A4 without N-terminal modifications

In this communication we reported a bacterial system that over-expressed full-length wild-type (WT) human CYP3A4 in Escherichia coli (E. coli) at a level of 495 nmol/L culture. This level of expression was achieved by cloning the cDNA sequence of CYP3A4 WT to a pLW01-P450 vector and co-expressing it with chaperones GroEL/ES in bacterial C41(DE3) cells. Aided with a C-terminal His5-tag, the expressed CYP3A4 WT was purified to homogeneity with a specific content of 14.3 ± 2.0 nmole P450/mg protein using a single Ni-Penta agarose column. Like the N-terminal modified form (CYP3A4-NF14), CYP3A4 WT binds substrate testosterone with a typical sigmoidal feature at slightly higher affinity. Functional characterization revealed that CYP3A4 WT exhibited lower testosterone 6β-hydroxylase activities than CYP3A4-NF14 in reconstituted phospholipid systems. In addition, it was found that the 6β-hydroxylase activity of CYP3A4 WT was less dependent on excess cytochrome P450 oxidoreductase (POR), compared with CYP3A4-NF14. These results suggest that the N-terminal membrane anchor of CYP3A4 WT enhances its interactions with POR and marginally increases testosterone binding.

Concentration-QT modeling demonstrates that the selective mineralocorticoid receptor modulator, balcinrenone (AZD9977), does not prolong QT interval.

Balcinrenone (AZD9977) is a selective mineralocorticoid receptor modulator in development in combination with dapagliflozin for treatment of heart failure with impaired kidney function and chronic kidney disease. A prespecified concentration-QT analysis was performed based on data from a phase I single ascending dose study prospectively designed as a thorough QT study substitute. Oral single doses of balcinrenone of 5-800 mg, plus fractionated doses of 800 and 1200 mg, were evaluated in 62 healthy male participants. Time-matched 12-lead digital electrocardiogram and plasma concentrations were measured pre-dose and up to 48 h postdose in the participants. Analysis was performed using a linear mixed-effect model, where baseline-adjusted Fridericia-corrected QT interval (ΔQTcF) was a dependent variable and time-matched balcinrenone concentration an independent variable. The model fit was deemed adequate by evaluation of goodness-of-fit plots, and the slope of the concentration-ΔQTcF relationship was nonsignificant (-0.003 ms/μmol/L; 95% confidence interval [CI]: -0.181, 0.176). The high clinical exposure scenario was defined as the maximum concentration (2.156 μmol/L) following the highest expected therapeutic dose (40 mg once daily) under fed conditions and in presence of a strong cytochrome P4503A4 inhibitor. Estimated baseline-adjusted and placebo-corrected QTcF interval (ΔΔQTcF) at this concentration was 0.35 ms (90% CI: -1.29, 2.00). Furthermore, the upper 90% ΔΔQTcF CI was estimated to be below the threshold of regulatory concern of 10 ms at all observed concentrations (up to 16.7 μmol/L). Hence, it can be concluded that balcinrenone does not induce QTcF prolongation at the high clinical exposure scenario.

Evidence that cadmium aggravate the toxicity of triphenyl phosphate in aquatic sediments to Corbicula fluminea

The ubiquitous co-existence of triphenyl phosphate (TPhP) and heavy metals in sediments raises significant biotoxicity concerns. However, uncertainty still exists regarding their combined toxicity to benthic organisms. Therefore, this research was conducted to elucidate the influences of cadmium (Cd) on TPhP toxicity to Corbicula fluminea (C. fluminea) in sediments. As a result, Cd promoted the accumulation of TPhP in C. fluminea and enhanced TPhP toxicity, manifested by damaged cell membranes and pronounced histological alterations. Molecular docking revealed that TPhP-Cd complexes exhibit greater binding affinity to cytochrome P4501A1 (CYP1A1) compared to TPhP alone. With the activity of CYP1A1 increasing, the biotransformation of TPhP was promoted in low-TPhP+Cd treatments (T5C0/T5C5/T5C35). Additionally, metabolites related to antioxidant defence and repair processes were reinforced to alleviate the toxicity of TPhP and Cd. However, excessive oxidative stress impaired the CYP1A1 activity in high-TPhP+Cd treatments (T35C0/T35C5/T35C35). Furthermore, metabolic pathway analysis revealed significant perturbations in the citrate cycle, alanine, aspartate and glutamate metabolism, purine metabolism, and pyrimidine metabolism. These disruptions weakened the repair capacity and aggravated apoptosis in digestive glands, potentially contributing to the synergistic toxicity of TPhP and Cd. The results highlight the ecological risks posed by TPhP in combination with heavy metals to benthic organisms.

Evaluation of Southern African wild edible plants for potential herb-drug interactions through ex vivo p-glycoprotein and in vitro cytochrome P450 3A4 inhibitory effects

BackgroundWild edible plants (WEPs) including herbs provide staple foods as well as income for local communities on the African continent. However, these commonly used plant materials interact with orthodox or conventional drugs through both p-glycoprotein (P-gp) and cytochrome P450 enzymes inhibition. Hence, it is vital to explore the possibility of herb-drug interactions when concomitantly taking conventional drug dosage forms with some of the WEPs. P-gp and CYP3A4 show analogous substrate specificities and work together to establish an intestinal absorption barrier against xenobiotics. This study investigated the ex vivo p-glycoprotein inhibition and the in vitro inhibition of cytochrome P450 3A4 (CYP3A4) isoezyme by selected wild edible plants to identify potential food/herb-drug interactions. Methods: Ethanolic extracts of 30 wild edible plants sourced from Lesotho, Eswatini and the Limpopo province of South Africa were used for the study. Drug transport studies using propranolol, a P-glycoprotein substrate, across porcine intestinal tissue were conducted using intestinal sacs with test solutions in Krebs-Ringer bicarbonate buffer (pH 7.4) under a 95 % O2/5 % CO2 atmosphere. For the in vitro luminescent-based CYP3A4 inhibition assay, both porcine liver and intestinal microsomes were extracted from their respective tissues by homogenization, followed by high-speed centrifugation and standardization before use. ResultsSisymbrium thelungii O. E. Schulz significantly (p < 0.05) inhibited P-gp with an effective apparent permeability coefficient (Papp eff) of (7.53±0.33) × 10–6 cm/s and effective flux (Jeff) of 1.38±0.01 µg/cm2/min which was similar to sodium orthovanadate (positive control), indicating potential for herb/food-drug interaction possibly by absorption enhancement of poorly permeable P-gp substrates by this plant. Additionally, both Rubus cuneifolius Pursh and Hypoxis hirsuta (L.) Coville had significant (p < 0.05) p-glycoprotein inhibitory effects with Papp eff of (6.60±0.52) × 10–6 cm/s and Jeff of 1.11±0.08 µg/cm2/min, and Papp eff of 6.58±0.67 × 10–6 cm/s and Jeff of 1.19±0.12 µg/cm2/min, respectively. Significantly (p < 0.05), Rubus cuneifolius at a concentration of 0.2 mg/mL exhibited the strongest CYP3A4 inhibition in liver microsomes suggesting its potential as a bioavailability enhancer of CYP3A4 substrates. Meanwhile, Wahlengergia androsacea A.DC exhibited the most significant (p < 0.05) CYP3A4 inhibitory effect at the same concentration in intestinal microsomes. ConclusionThe observed inhibitory effects of certain wild edible plants on P-gp-mediated drug efflux and CYP3A4 drug metabolism indicate potential food/herb-drug interactions challenges for clinical practice. The herb/food-drug interactions also present opportunities for discovery of new functional excipients for enhancing the permeability of poorly absorbed orally administered drugs that are substrates of P-gp and CYP3A4.

Anti-Alzheimer's Disease Target and Beneficial Effect in Formononetin

Introduction: Alzheimer's Disease (AD), a common neurodegenerative relevance of dementia, is spreading in the world. Hitherto, the pharmacological treatment for AD is prescribed limitedly in clinical application. Recently, it has been found that naturally occurring extracts possess promising anti-neurodegenerative properties, including AD. Method: Our previous study indicated that formononetin (FMN) exerts the anti-AD benefits based on bioinformatics analysis. However, the experimental validation for bioinformatics findings has not been conducted. In this study, we primarily applied the molecule docking analysis to ascertain the pharmacological targets, including cytochrome P450 19A1 (CYP19A1). Transgenic AD mice were used to validate the bioinformatics findings in vivo experimentally. Molecular docking data showed that FMN acted directly on CYP19A1 target protein with effective binding sites and potent combining affinity/energy. Results: Meanwhile, FMN intervention contributed to an increased trend of body weight in transgenic AD mice reduced hippocampal expression of Aβ1-42, and elevated content of CYP19A1. Additionally, FMN intervention showed reduced terminal deoxynucleotidyl Transferase dUTP Nick-End Labeling (TUNEL) expression and increased CYP19A1 and Ki67 expressions in hippocampal sections of transgenic AD mice. Conclusion: Collectively, FMN may be used for the prevention of AD, and the pharmacological activities are possibly related to reducing Aβ1-42, and TUNEL expressions to increase Ki67 and CYP19A1 activities.

In silico discovery of potential androgen receptor and cytochrome P450 17A1 inhibitors from Camellia sinensis for prostate cancer treatment

Prostate cancer is the second most prevalent cancer among men worldwide. Despite the significant research into its therapeutics, the current treatments remain expensive with side effects. Hence, there is a significant need for new therapeutic solutions. Thus, this study aimed to investigate the potential of bioactive compounds from Camellia sinensis as inhibitors of the androgen receptor (AR) and Cytochrome P450 17A1 (CYP17A1), offering a novel approach for prostate cancer treatment. The bioactive compounds from C. sinensis were obtained from Dr. Duke's Phytochemical and Ethnobotanical Database (DPED). The target proteins were obtained from Protein Data Bank (PDB) and prepared using Biovia Discovery Studio 2021. Active sites of the target proteins were identified using the Computed Atlas of Surface Topography of Proteins 3.0 (CASTp 3.0) database, and molecular docking analysis were conducted using the Autodock Vina plugin on PyRx software. Druglikeness and ADMET prediction were assessed using SwissAdme, admetSAR2.0, and Protox II, while molecular dynamics simulation and Molecular Mechanics-Generalized Born Surface Area analysis were performed using the Schrodinger LLC Desmond/Prime program. Out of the 117 phytocompounds retrieved, 25 phytocompounds were non-carcinogenic and positive for AR binding, while more than half showed non-promiscuity in inhibiting cytochrome variants. All 25 compounds exhibited lower binding affinity against AR and CYP17A1 compared to the controls. Specifically, Theaflavine-3,3′-digallate, Epitheaflagallin 3-O-gallate, and Gallocatechin gallate formed the best complexes with AR, while Thearubgin, Theasinensin B, and Theaflavin monogallates exhibited the most favorable interactions with CYP17A1. Additionally, these compounds showed remarkable druggability qualities. Molecular dynamics simulation validated that Gallocatechin gallate, Epitheaflagallin 3-O-gallate formed excellent stability with AR while Thearugbin and Theaflavin monogallates also exhibited commendable stability with CYP17A1 protein. Thus, the bioactives are recommended for further studies to test efficacy and toxicity.

Increased susceptibility to diet-induced obesity in female mice impairs ovarian steroidogenesis: The role of elevated leptin signalling on nodal activity inhibition in theca cells

ObjectivesSusceptibility to obesity in humans is driven by the intricate interplay of genetic, environmental and behavioural factors. Moreover, the mechanisms linking maternal obesity to infertility remain largely understudied. In this study, we investigated how variable susceptibility to obesity in mice affects ovarian steroidogenesis, with a particular focus on the leptin-mediated dysregulation of Nodal signalling pathway in theca cells (TC). MethodsC56BL/6J (B6) and 129S1/SvlmJ (129) mice, models of maternal obesity (MO), were fed a chow diet (CD) and a high fat diet (HFD) for 16 weeks. To investigate the contrasting effects of leptin on ovarian steroidogenesis, B6 mice pharmacologically treated with leptin for 16 days on CD were used to model hyperleptinemia, while homozygous ob/ob (−/−) mice with genetic leptin deficiency, also on a CD, were used to examine the effects of obesity in the absence of leptin. Following the characterisation of the mouse phenotype, gonadal fat (GON), whole ovaries (WO), ovarian TC and granulosa cell (GC) fractions were collected for mRNA transcription and protein expression analysis. Finally, in vitro treated ovarian explants obtained from B6 mice were used to further elucidate the effects of Nodal on steroidogenesis. ResultsThe significant gain in body weight (BW) and fat mass (FM) in HFD-fed B6 mice (p < 0.05), was associated with increased mRNA transcription of the adipose tissue expansion genes Polymerase I and transcript release factor (Cavin), Secreted frizzled-related protein 5 (Sfrp5) and Mesoderm specific transcript (Mest) in GON (p < 0.05). Furthermore, the HFD-fed B6 mice presented also impaired glucose metabolism and insulin sensitivity (p < 0.05). In contrast, the HFD-fed 129 mice exhibited no changes in BW and FM, maintaining glucose and insulin metabolism. At the ovarian level, decreased protein expression of Steroidogenic Acute Regulatory Protein (StAR) in WO obtained from HFD-fed B6 mice (p = 0.05), was followed by reduced transcription of key steroidogenic genes like Star and Cytochrome P450 17a1 (Cyp17a) in TC (p < 0.05). Furthermore, the transcription of Nodal and its receptors was downregulated (p < 0.05), whereas mRNA levels of Suppressor of cytokine signalling 3 (Socs3) and SMAD family member 7 (Smad7) were upregulated in TC obtained from HFD-fed B6 mice (p < 0.05). No changes were seen in the genes regulating steroidogenesis, Nodal signalling, or Socs3 and Smad7 activity in the ovaries of HFD-fed 129 mice. Importantly, the pharmacological treatment of lean mice with leptin, upregulated the ovarian transcription of Socs3 and Smad7, while downregulating Nodal and its receptors (p < 0.05). Finally, in vitro pharmacological inhibition of Nodal signalling pathway in ovarian explants isolated from CD-fed B6 mice decreased the transcription of Star and Cyp17a in TC (p < 0.05), whereas Nodal treatment of explants obtained from HFD-fed B6 mice restored the transcription of both genes (p < 0.05). ConclusionsIncreased susceptibility to obesity in MO is associated with systemic hyperleptinemia and hypoestrogenism due to compromised ovarian steroidogenesis, largely driven by the inhibitory effects of leptin-Smad7 pathway on Nodal signalling activity in the TC compartment of ovarian follicles.

Concentration-QTcF analysis of quizartinib in patients with newly diagnosed FLT3-internal-tandem-duplication-positive acute myeloid leukemia.

Quizartinib prolongs QT interval through inhibition of the slow delayed rectifier potassium current (IKs). We used non-linear mixed-effects modeling to explore the relationship between quizartinib and its pharmacologically active metabolite AC886 and the Fridericia-corrected QT interval (QTcF) in newly diagnosed acute myeloid leukemia (AML) patients. We evaluated linear and non-linear drug effect models, using triplicate QTcF measurements with available time-matched pharmacokinetic samples from the Phase 3 QuANTUM-First trial. The effect of intrinsic and extrinsic factors on model parameters was tested using stepwise covariate model building. Simulations were conducted to predict the change from baseline in QTcF (ΔQTcF) at the maximum concentration at steady-state (Cmax,ss) for quizartinib maintenance daily doses of 30 and 60 mg. The concentration-QTcF (C-QTcF) relationship was best described by a sigmoidal maximum effect model. After accounting for the effect of quizartinib, including AC886 concentrations did not further explain changes in QTcF. Circadian variations in QTcF were described using an empirical change from baseline based on clock times. Age and hypokalaemia were identified as statistically significant covariates on baseline QTcF; no covariates were found to impact the C-QTcF relationship. The median model-predicted ΔQTcF at Cmax,ss was 18.4 ms (90% confidence interval (CI): 16.3-20.5) at 30 mg and 24.1 ms (90% CI: 21.4-26.6) at 60 mg. In conclusion, in newly diagnosed AML patients, ΔQTcF increased non-linearly with increasing quizartinib concentrations. The predicted ΔQTcF increase at Cmax,ss supports the proposed dose adaptation based on observed QTcF and the dose reduction in case of strong cytochrome P450 3A (CYP3A) inhibitors coadministration.