Cytochrome P450 Activity Research Articles

Metabolism of a fungicide propiconazole by Cunninghamella elegans ATCC36112.

The metabolic breakdown of propiconazole by fungi was examined, and it was found that the microbial model (Cunninghamella elegans ATCC36112) efficiently degrades the triazole fungicide propiconazole through the action of cytochrome P450. This enzyme primarily facilitates the oxidation and hydrolysis processes involved in phase I metabolism. We observed major metabolites indicating hydroxylation/oxidation of propyl groups of propiconazole. Around 98% of propiconazole underwent degradation within a span of 3days post-treatment, leading to the accumulation of five metabolites (M1-M5). The experiments started with a preliminary identification of propiconazole and its metabolites using GC-MS. The identified metabolites were then separated and identified by in-depth analysis using preparative UHPLC and MS/MS. The metabolites of propiconazole are M1 (CGA-118245), M2(CGA-118244), M3(CGA-136735), M4(GB-XLIII-42-1), and M5(SYN-542636). To further investigate the role of key enzymes in potential fungi, we treated the culture medium with piperonyl butoxide (PB) and methimazole (MZ), and then examined the kinetic responses of propiconazole and its metabolites. The results indicated a significant reduction in the metabolism rate of propiconazole in the medium treated with PB, while methimazole showed weaker inhibitory effects on the metabolism of propiconazole in the fungus C. elegans.

Predicting the Intravenous Pharmacokinetics of Covalent Drugs in Animals and Humans.

30 covalent drugs were used to assess clearance (CL) prediction reliability in animals and humans. In animals, marked CL underprediction was observed using cryopreserved hepatocytes or liver microsomes (LMs) supplemented for cytochrome P450 activity. Improved quantitative performance was observed by combining metabolic stability data from LMs and liver S9 fractions, the latter supplemented with reduced glutathione for glutathione transferase activity. While human LMs provided reliable human CL predictions, prediction statistics were improved further by incorporating S9 stability data. CL predictions with allometric scaling were less robust compared to in vitro drug metabolism methods; the best results were obtained using the fu-corrected intercept model. Human volume of distribution (Vd) was well predicted using allometric scaling of animal pharmacokinetic data; the most reliable results were achieved using simple allometric scaling of unbound Vd values. These results provide a quantitative framework to guide appropriate method selection for human PK prediction with covalent drugs.

A flexible linker of 8-amino acids between the membrane binding segment and the FMN domain of cytochrome P450 reductase is necessary for optimal activity

The diflavin NADPH-cytochrome P450 reductase (CYPOR) plays a critical role in human cytochrome P450 (CYP) activity by sequentially delivering two electrons from NADPH to CYP enzymes during catalysis. Although electron transfer to forty-eight human CYP enzymes by the FMN hydroquinone of CYPOR is well-known, the role of the linker between the NH2-terminus membrane-binding domain (MBD) and FMN domain in supporting the activity of P450 enzymes remains poorly understood. Here we demonstrate that a linker with at least eight residues is required to form a functional CYPOR-CYP2B4 complex. The linker has been shortened in two amino-acid increments from Phe44 to Ile57 using site directed mutagenesis. The ability of the deletion mutants to support cytochrome P450 2B4 (CYP2B4) catalysis and reduce ferric CYP2B4 was determined using an in vitro assay and stopped-flow spectrophotometry. Steady-state enzyme kinetics showed that shortening the linker by 8–14 amino acids inhibited (63–99%) the ability of CYPOR to support CYP2B4 activity and significantly increased the Km of CYPOR for CYP2B4. In addition, the reductase mutants decreased the rate of reduction of ferric CYP2B4 (46–95%) compared to wildtype when the linker was shortened by 8–14 residues. These results indicate that a linker with a minimum length of eight residues is necessary to enable the FMN domain of reductase to interact with CYP2B4 to form a catalytically competent complex. Our study provides evidence that the length of the MBD-FMN domain linker is a major determinant of the ability of CYPOR to support CYP catalysis and drug metabolism by P450 enzymes. PreambleThis manuscript is dedicated in memory of Dr. James R. Kincaid who was the doctoral advisor to Dr. Freeborn Rwere and a longtime collaborator and friend of Dr. Lucy Waskell. Dr. James R. Kincaid was a distinguished professor of chemistry specializing in resonance Raman (rR) studies of heme proteins. He inspired Dr. Rwere (a Zimbabwean native) and three other Zimbabweans (Dr. Remigio Usai, Dr. Daniel Kaluka and Ms. Munyaradzi E. Manyumwa) to use lasers to document subtle changes occurring at heme active site of globin proteins (myoglobin and hemoglobin) and cytochrome P450 enzymes. Dr. Rwere appreciate his contributions to the development of talented Black scientists from Africa.

Cytochrome P450 2J2 is required for the natural compound austocystin D to elicit cancer cell toxicity.

Austocystin D is a natural compound that induces cytochrome P450 (CYP) monooxygenase-dependent DNA damage and growth inhibition in certain cancer cell lines. Cancer cells exhibiting higher sensitivity to austocystin D often display elevated CYP2J2 expression. However, the essentiality and the role of CYP2J2 for the cytotoxicity of this compound remain unclear. In this study, we demonstrate that CYP2J2 depletion alleviates austocystin D sensitivity and DNA damage induction, while CYP2J2 overexpression enhances them. Moreover, the investigation into genes involved in austocystin D cytotoxicity identified POR and PGRMC1, positive regulators for CYP activity, and KAT7, a histone acetyltransferase. Through genetic manipulation and analysis of multiomics data, we elucidated a role for KAT7 in CYP2J2 transcriptional regulation. These findings strongly suggest that CYP2J2 is crucial for austocystin D metabolism and its subsequent cytotoxic effects. The potential use of austocystin D as a therapeutic prodrug is underscored, particularly in cancers where elevated CYP2J2 expression serves as a biomarker.

Thiamylal serum concentration for refractory convulsive status epilepticus while associated decreased concentrations of concomitant antiepileptics: a case report

BackgroundTreating refractory status epilepticus (RSE) remains a challenge. Thiamylal can be used as a second- or third-line treatment; however, its potential to induce cytochrome P450 (CYP) activity may reduce the concentration of antiepileptic drugs (AEDs) administered prior to thiamylal. This report details a case of RSE patient treated with thiamylal, with monitored concentrations of thiamylal and other AEDs.Case presentationA 72-year-old healthy man developed RSE. Despite the administration of various AEDs, his seizures were not resolved. Thiamylal was then administered at an initial bolus dose of 2.1 mg/kg, followed by a continuous infusion of 4.2–5.2 mg/kg/h. The initial thiamylal concentration was observed at 7.8 μg/mL, increasing to 35.2 μg/mL before decreasing after dose reduction and cessation. Concurrently, the concentration of concomitant carbamazepine decreased from 5.59 μg/mL to 2.1 μg/mL and recovered as thiamylal concentration decreased. Lesser impacts were noted for other AEDs.ConclusionsThis case report underscored the efficacy of thiamylal in treating RSE. However, it also highlighted the need for clinicians to closely monitor the concentrations of concurrent AEDs, especially carbamazepine, during thiamylal therapy.

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.

Decoding the Role of CYP450 Enzymes in Metabolism and Disease: A Comprehensive Review.

Cytochrome P450 (CYP450) is a group of enzymes that play an essential role in Phase I metabolism, with 57 functional genes classified into 18 families in the human genome, of which the CYP1, CYP2, and CYP3 families are prominent. Beyond drug metabolism, CYP enzymes metabolize endogenous compounds such as lipids, proteins, and hormones to maintain physiological homeostasis. Thus, dysregulation of CYP450 enzymes can lead to different endocrine disorders. Moreover, CYP450 enzymes significantly contribute to fatty acid metabolism, cholesterol synthesis, and bile acid biosynthesis, impacting cellular physiology and disease pathogenesis. Their diverse functions emphasize their therapeutic potential in managing hypercholesterolemia and neurodegenerative diseases. Additionally, CYP450 enzymes are implicated in the onset and development of illnesses such as cancer, influencing chemotherapy outcomes. Assessment of CYP450 enzyme expression and activity aids in evaluating liver health state and differentiating between liver diseases, guiding therapeutic decisions, and optimizing drug efficacy. Understanding the roles of CYP450 enzymes and the clinical effect of their genetic polymorphisms is crucial for developing personalized therapeutic strategies and enhancing drug responses in diverse patient populations.

Biphasic effects of ethanol consumption on N,N-dimethylformamide-induced liver injury in mice

N,N-Dimethylformamide (DMF) is a well-documented occupational hazardous material, which can induce occupational liver injury. The current study was designed to investigate whether ethanol consumption can affect DMF-induced hepatotoxicity and the potential underlying mechanisms involved. We found that a single dose of ethanol (1.25, 2.5, or 5 g/kg bw by gavage) significantly repressed the increase in serum alanine transaminase (ALT) and aspartate transaminase (AST) activities and alleviated the liver histopathological changes in mice challenged with 3 g/kg DMF. In contrast, long-term moderate drinking (2.5 g/kg bw) significantly aggravated the repeated DMF (0.7 g/kg bw) exposure-induced increase in the serum ALT and AST activities. Mechanistically, acute ethanol consumption suppressed DMF-induced activation of the NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome, while long-term moderate ethanol consumption promoted hepatocyte apoptosis in the mouse liver. Notably, cytochrome P4502E1 (CYP2E1) protein level and activity in mouse livers were not significantly affected by ethanol per se in the two models. These results confirm that regular drinking can increase the risk of DMF-induced hepatotoxicity, and suggest that DMF-handling workers should avoid consuming ethanol to reduce the risk of DMF-indued liver injury.

Targeting of CYP2E1 by miRNAs in alcohol-induced intestine injury

Although binge alcohol-induced gut leakage has been studied extensively in the context of reactive oxygen species (ROS)-mediated signaling, it was recently revealed that post-transcriptional regulation plays an essential role as well. Ethanol (EtOH)-inducible cytochrome P450-2E1 (CYP2E1), a key enzyme in EtOH metabolism, promotes alcohol-induced hepatic steatosis and inflammatory liver disease, at least in part by mediating changes in intestinal permeability. For instance, gut leakage and elevated intestinal permeability to endotoxins have been shown to be regulated by enhancing CYP2E1 mRNA and CYP2E1 protein levels. Although it is understood that EtOH promotes CYP2E1 induction and activation, the mechanisms that regulate CYP2E1 expression in the context of intestinal damage remain poorly defined. Specific miRNAs, including miR-132, miR-212, miR-378, and miR-552, have been shown to repress the expression of CYP2E1, suggesting that these miRNAs contribute to EtOH-induced intestinal injury. Here, we have shown that CYP2E1 expression is regulated post-transcriptionally through miRNA-mediated degradation, as follows: 1) the RNA-binding protein AU-binding Factor 1 (AUF1) binds mature miRNAs, including CYP2E1-targeting miRNAs, and this binding modulates the degradation of corresponding target mRNAs upon EtOH treatment; 2) the Serine/Threonine kinase MST1 mediates oxidative stress-induced phosphorylation of AUF1. Those findings suggest that ROS-mediated signaling modulates AUF1/miRNA interaction through MST1-mediated phosphorylation. Thus, our study demonstrates the critical functions of AUF1 phosphorylation by MST1 in the decay of miRNAs targeting CYP2E1, the stabilization of CYP2E1 mRNA in the presence of EtOH, and the relationship of this pathway to subsequent intestinal injury.

Baseline of susceptibility, risk assessment, biochemical mechanism, and fitness cost of resistance to dimpropyridaz, a novel pyridazine pyrazolecarboxamide insecticide, in Bemisia tabaci from China

Bemisia tabaci is one of the most destructive agricultural insect pests around the world, and it has developed high levels of resistance to most pesticides. Dimpropyridaz, a novel insecticide developed by BASF, displays excellent activity against piercing-sucking insect pests. In this study, baseline of susceptibility showed all tested field populations of B. tabaci are susceptible to dimpropyridaz. After continuous selection with dimpropyridaz in the lab, a B. tabaci strain (F12) developed 2.2-fold higher level of resistance compared with a susceptible MED-S strain, and the realized heritability (h2) was estimated as 0.0518. The F12 strain displayed little cross-resistance to afidopyropen, cyantraniliprole, sulfoxaflor, or abamectin, and significantly increased activity of cytochrome P450 monooxygenase (P450). The fitness cost of dimpropyridaz resistance was evident in F12 strain, which had a relative fitness of 0.95 and significantly lower fecundity per female compared with MED-S strain. Taken together, B. tabaci displays high susceptibility to dimpropyridaz in the field, and low risk of developing resistance to dimpropyridaz under successive selection pressure. Little cross-resistance to popular insecticides was found, and fitness cost associated dimpropyridaz resistance was observed. Higher activity of cytochrome P450 in the F12 strain, may be involved in the process of detoxifying dimpropyridaz in whitefly.

Decoding defenses: Biochemical insights into insecticide resistance in tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae) from tea plantations of Eastern India

Helopeltis theivora is one of the major tea pests in India and the strategies of management largely depend on application of different insecticides. Resistance in ten field populations of H. theivora collected from different tea growing regions of Eastern India to three insecticides was evaluated by leaf dip method in the laboratory. The results showed varied levels of susceptibility in nine populations to thiamethoxam and deltamethrin with a resistance coefficient (RC) ranging from 2.04 to 30.95 and 1.56–59.81-fold, respectively. Upper Assam and Central Dooars populations showed high resistance to thiamethoxam and deltamethrin. A high resistance to deltamethrin was also recorded in the Eastern Dooars (RC = 52.74) and Western Dooars (RC = 53.07) populations. There was no resistance to quinalphos in any of the populations (RC = 0.11–0.60). The Darjeeling population was relatively susceptible to the insecticides. Biochemical enzyme assays suggested that glutathione S-transferases (GST), general esterase (GE) and cytochrome P450 (CYP) activities were high in most of the field populations as compared to the susceptible population. However, the expression of CYP was statistically at par between the Cachar, Tripura, Darjeeling and susceptible population. GST and GE activity displayed a strong significant correlation with LC50 values of thiamethoxam and deltamethrin while a moderate to strong linear relationship was recorded between CYP and the LC50s of thiamethoxam and deltamethrin, respectively. A weak positive correlation was established between LC50 of quinalphos and the enzymes. Synergistic assays reveal that the addition of synergists’ piperonyl butoxide and diethyl maleate with thiamethoxam and deltamethrin enhanced the toxicity of these insecticides. The results of this study will contribute to the insecticide resistance management and integrated management of H. theivora.

Two Cytochrome P450s, CYP709B1 and CYP704C1, Play Essential Roles in Metabolism-Based Multiple Herbicide Resistance in American Sloughgrass (Beckmannia syzigachne (Steud.) Fernald).

This study confirmed a field population of American sloughgrass (Beckmannia syzigachne (Steud.) Fernald) that developed simultaneously high levels of resistance (resistance index >10) to three divergent modes of action herbicides: fenoxaprop-P-ethyl, mesosulfuron-methyl, and isoproturon. The resistance phenotype observed in this population was not attributed to target-site alterations; rather, the resistant plants exhibited a significant increase in the activity of cytochrome P450s (P450s) and enhanced metabolism rates for all three herbicides. RNA sequencing revealed significant upregulation of two P450s, CYP709B1 and CYP704C1, in the resistant plants both before and after herbicide treatments. Molecular docking predicted that the homology models of these P450s should exhibit a binding affinity for a range of herbicides. The heterologous expression of the identified P450s in yeast cells indicated improved growth in the presence of all three of the aforementioned herbicides. Collectively, the increased expression of CYP709B1 and CYP704C1 likely contributed to the P450s-mediated enhanced metabolism, thereby conferring multiple herbicide resistance in B. syzigachne.

Evaluating drug interaction potential from cytokine release syndrome using a physiologically based pharmacokinetic model: A case study of teclistamab.

Cytokine release syndrome (CRS) was associated with teclistamab treatment in the phase I/II MajesTEC-1 study. Cytokines, especially interleukin (IL)-6, are known suppressors of cytochrome P450 (CYP) enzymes' activity. A physiologically based pharmacokinetic model evaluated the impact of IL-6 serum levels on exposure of substrates of various CYP enzymes (1A2, 2C9, 2C19, 3A4, 3A5). Two IL-6 kinetics profiles were assessed, the mean IL-6 profile with a maximum concentration (Cmax) of IL-6 (21 pg/mL) and the IL-6 profile of the patient presenting the highest IL-6 Cmax (288 pg/mL) among patients receiving the recommended phase II dose of teclistamab in MajesTEC-1. For the mean IL-6 kinetics profile, teclistamab was predicted to result in a limited change in exposure of CYP substrates (area under the curve [AUC] mean ratio 0.87-1.20). For the maximum IL-6 kinetics profile, the impact on omeprazole, simvastatin, midazolam, and cyclosporine exposure was weak to moderate (mean AUC ratios 1.90-2.23), and minimal for caffeine and s-warfarin (mean AUC ratios 0.82-1.25). Maximum change in exposure for these substrates occurred 3-4 days after step-up dosing in cycle 1. These results suggest that after cycle 1, drug interaction from IL-6 effect has no meaningful impact on CYP activities, with minimal or moderate impact on CYP substrates. The highest risk of drug interaction is expected to occur during step-up dosing up to 7 days after the first treatment dose (1.5 mg/kg subcutaneously) and during and after CRS.

Advanced three-dimensional in vitro liver models to study the activity of anticancer drugs.

The liver is one of the most important organs in the human body. It performs many important functions, including being responsible for the metabolism of most drugs, which is often associated with its drug-induced damage. Currently, there are no ideal pharmacological models that would allow the evaluation of the effect of newly tested drugs on the liver in preclinical studies. Moreover, the influence of hepatic metabolism on the effectiveness of the tested drugs is rarely evaluated. Therefore, in this work we present an advanced model of the liver, which reflects most of the morphologically and metabolically important features of the liver in vivo, namely: three-dimensionality, cellular composition, presence of extracellular matrix, distribution of individual cell types in the structure of the liver model, high urea and albumin synthesis efficiency, high cytochrome p450 activity. In addition, the work, based on the example of commonly used anticancer drugs, shows how important it is to take into account hepatic metabolism in the effective assessment of their impact on the target organ, in this case cancer. In our research, we have shown that the most similar to liver in vivo are 3D cellular aggregates composed of three important liver cells, namely hepatocytes (HepG2), hepatic stellate cells (HSCs), and hepatic sinusoidal endothelial cells (HSECs). Moreover, we showed that the cells in 3D aggregate structure need time (cell-cell interactions) to improve proper liver characteristic. The triculture model additionally showed the greatest ability to metabolize selected anticancer drugs.

In vivo upstream factors of mouse hepatotoxic mechanism with sustained hepatic glutathione depletion: Acetaminophen metabolite-erythrocyte adducts and splenic macrophage-generated reactive oxygen species

Investigation of acetaminophen (APAP)-induced liver damage recently indicated the significance of phagocytic NADPH oxidase (NOX)-derived reactive oxygen species (ROS) and ferroptosis in the liver. Here, we focused on phagocytosis by iron-containing erythrocyte-devouring splenic macrophages and explored upstream factors of known APAP hepatotoxic mechanisms in vivo. Splenectomy did not alter hepatic cytochrome P450 (CYP) 2E1 activity or hepatic glutathione (GSH) content. APAP injection into splenectomized mice almost completely suppressed increases in plasma alanine aminotransferase levels and centrilobular hepatic necrosis showing the spleen to be a critical tissue in APAP-induced liver damage. Hepatic GSH was recovered to approximately 50 % content at 8 h. In non-splenectomized mice, liver damage was dramatically suppressed by a sensitive redox probe (DCFH-DA), macrophage-depleting clodronate (CL), and a NOX2 inhibitor. APAP treatment resulted in markedly stronger fluorescence intensity from DCFH-DA due to excessive ROS around splenic macrophages, which was lost upon co-treatment with a CYP inhibitor and CL. Deformed erythrocytes disappeared in mice co-treated with DCFH-DA, CL, the NOX2 inhibitor, and the CYP inhibitor. Simultaneously, these four compounds significantly improved APAP-depleted GSH levels. The CYP inhibitor also prevented the formation of APAP-cell adducts in the blood and spleen. In the spleen, CL co-treatment markedly reduced the number of adducts. Splenic ferrous iron levels were significantly elevated by APAP. Therefore, we demonstrated that splenic macrophages devoured APAP metabolite-erythrocyte adducts and subsequently splenic macrophage-related ROS caused sustained hepatic GSH depletion and excessive erythrocyte deformation around 7 h. Our data indicate in vivo upstream factors of known APAP hepatotoxic mechanisms.

Revealing the Role of CYP346 Family Genes on Phosphine Resistance in Indian Populations of Tribolium castaneum.

Phosphine resistance in Tribolium castaneum challenges grain storage. This study investigates the impact of cytochrome P450 (CYP) enzymes and CYP346 family genes on phosphine resistance in Indian Tribolium castaneum populations. Seven field populations of T. castaneum were compared with Lab- susceptible population for their resistance to phosphine. The levels of cytochrome P450 enzyme and expression of certain CYP346 family genes were tracked in these populations. The highly resistant Patiala population showed significantly increased CYP450 activity (11.26 ± 0.14 nmol/min/mg protein, 7.41-fold higher) compared to the lab-susceptible population (1.52 ± 0.09 nmol/min/mg protein) when assayed using 8 mM p-nitroanisole as the substrate. The mRNA expression was measured relative to the standard gene RPS18 and revealed significant upregulation of CYP346B1 and CYP346B3 in highly resistant populations Moga and Patiala (CYP346B1: 12.09 ± 2.19 to 21.74 ± 3.82; CYP346B3: 59.097 ± 10.265 to 50.148 ± 8.272). Patiala's CYP346B1 exhibited an impressive 685.76-fold change, and Moga's CYP346B3 showed a 361.893-fold change compared to lab-susceptible. Linear regression confirmed robust fits for each gene (R2: 0.693 to 0.756). Principal component analysis (PCA) demonstrated a strong positive correlation between CYP346 genes expression; and cytochrome P450 activity. Patiala, Moga, and Hapur populations showed conformity, associating higher resistance with increased P450 activity and CYP346 gene expression. Cluster analysis highlighted a potential correlation between CYP346B1, CYP346B2, and CYP346B3 and P450 activity, with Patiala and Moga clustering together. Variability in CYP346B1 and CYP346B3 in strong resistance populations may contribute to adaptation and resistance mechanisms. The study provides insights into specific CYP346 family genes associated with phosphine resistance, emphasizing the intricate interaction between CYP450 detoxifying enzymes, CYP346 family genes, and resistance mechanisms. The upregulation of CYP346 genes suggests a survival advantage for T. castaneum against phosphine, diminishing phosphine's efficacy as a pest control measure.

P450 gene CYP6a13 is responsible for cross-resistance of insecticides in field populations of Spodoptera frugiperda.

Continuous and long-term use of traditional and new pesticides can result in cross-resistance among pest populations in different fields. Study on the mechanism of cross-resistance and related genes will help resistance management and field pest control. In this study, the pesticide-resistance mechanism in Spodoptera frugiperda (FAW) was studied with field populations in 3 locations of South China. Field FAW populations were highly resistant to traditional insecticides, chlorpyrifos (organophosphate) and deltamethrin (pyrethroid), and had higher levels of cytochrome P450 activity than a non-resistant laboratory strain. Inhibition of P450 activity by piperonyl butoxide significantly increased the sensitivity of resistant FAW in 3 locations to chlorpyrifos, deltamethrin and chlorantraniliprole (amide), a new type of insecticide, suggesting that P450 detoxification is a critical factor for insecticide resistance in field FAW populations. Transcriptomic analysis indicated that 18 P450 genes were upregulated in the field FAW populations collected in 3 regions and in 2consecutive years, with CYP6a13, the most significantly upregulated one. Knockdown of CYP6a13 messenger RNA by RNA interference resulted in an increased sensitivity to the 3 tested insecticides in the field FAW. Enzyme activity and molecular docking analyses indicated that CYP6a13 enzyme was able to metabolize the 3 tested insecticides and interact with 8 other types of insecticides, confirming that CYP6a13 is a key cross-resistance gene with a wide range of substrates in the field FAW populations across the different regions and can be used as a biomarker and target for management of FAW insecticide resistance in fields.

Validating Well-Functioning Hepatic Organoids for Toxicity Evaluation.

"Organoids", three-dimensional self-organized organ-like miniature tissues, are proposed as intermediary models that bridge the gap between animal and human studies in drug development. Despite recent advancements in organoid model development, studies on toxicity using these models are limited. Therefore, in this study, we aimed to analyze the functionality and gene expression of pre- and post-differentiated human hepatic organoids derived from induced pluripotent stem cells and utilize them for toxicity assessment. First, we confirmed the functional similarity of this hepatic organoid model to the human liver through various functional assessments, such as glycogen storage, albumin and bile acid secretion, and cytochrome P450 (CYP) activity. Subsequently, utilizing these functionally validated hepatic organoids, we conducted toxicity evaluations with three hepatotoxic substances (ketoconazole, troglitazone, and tolcapone), which are well known for causing drug-induced liver injury, and three non-hepatotoxic substances (sucrose, ascorbic acid, and biotin). The organoids effectively distinguished between the toxicity levels of substances with and without hepatic toxicity. We demonstrated the potential of hepatic organoids with validated functionalities and genetic characteristics as promising models for toxicity evaluation by analyzing toxicological changes occurring in hepatoxic drug-treated organoids.

Pharmacological Implications of Natural Products of Fruits and Vegetable Origin on the Activity of Cytochrome P450 Enzymes

The primary goal of drug metabolism, sometimes referred to as pharmacokinetic process, is to change a medication's chemical structure to make it more readily excretable. Typically, phase I and phase II reactions involve this mechanism. Xenobiotics can stimulate or inhibit the activity of cytochrome P450 (CYP450) enzymes involved in phase I processes. The goal of this research is to clarify the clinical significance of CYP450 induction and inhibition by demonstrating how certain bioactive compounds found in foods or natural products derived from fruits and vegetables can alter CYP450 enzyme activity, impacting drug bioavailability and depuration in addition. The interaction between natural products and foods derived from fruits and vegetables and some pharmaceuticals that can result in toxicity or therapeutic failure will be explained with a few instances. This will make it possible to compile pertinent data regarding appropriate pharmaceutical management in a range of clinical contexts.

Herbicide safener isoxadifen-ethyl associated with increased Goss's wilt severity in corn (Zea mays).

Goss's bacterial wilt and leaf blight (Goss's wilt), caused by the bacterium Clavibacter nebraskensis, is a corn disease that has been a top ten yield-reducing disease in North America in the past 15 years. Isoxadifen-ethyl is an herbicide safener that effectively increases cytochrome P450 activity in corn which enhances a plant's metabolism of herbicide molecules. Recent research found a potential link between isoxadifen-ethyl and increased Goss's wilt severity. The application of isoxadifen-ethyl increased (P = 0.014-0.046) area under disease progress curve (AUDPC) by 19%, 7%, and 9% at three environments, independent of accompanying herbicide or herbicide application timing. However, no significant differences in incidence of systemic wilt or corn grain yield occurred among treatments at any environment. These data provide evidence for an association between isoxadifen-ethyl safener and Goss's wilt in corn. The reason for this association is unknown, but the safener may affect plant or pathogen physiological mechanisms. While the increased disease severity did not result in decreased grain yield in these experiments, an increase in pathogen inoculum due to higher disease severity could influence Goss' wilt epidemics in future years. © 2024 Society of Chemical Industry.