Cytochrome P450s Research Articles

Tomato Spotted Wilt Virus Suppresses the Antiviral Response of the Insect Vector, Frankliniella occidentalis, by Elevating an Immunosuppressive C18 Oxylipin Level Using Its Virulent Factor, NSs.

Orthotospovirus tomatomaculae (tomato spotted wilt virus, TSWV) is transmitted by the western flower thrips, Frankliniella occidentalis. Epoxyoctadecamonoenoic acids (EpOMEs) function as immune-suppressive factors, particularly in insects infected by viral pathogens. These oxylipins are produced by cytochrome P450 monooxygenases (CYPs) and are degraded by soluble epoxide hydrolase (sEH). In this study, we tested the hypothesis that TSWV modulates the EpOME level in the thrips to suppress antiviral responses and enhance its replication. TSWV infection significantly elevated both 9,10-EpOME and 12,13-EpOME levels. Following TSWV infection, the larvae displayed apoptosis in the midgut along with the upregulated expression of four caspase genes. However, the addition of EpOME to the viral treatment notably reduced apoptosis and downregulated caspase gene expressions, which led to a marked increase in TSWV titers. The CYP and sEH genes of F. occidentalis were identified, and their expression manipulation using RNA interference (RNAi) treatments led to significant alternations in the insect's immune responses and TSWV viral titers. To ascertain which viral factor influences the host EpOME levels, specialized RNAi treatments targeting genes encoded by TSWV were administered to larvae infected with TSWV. These treatments demonstrated that NSS expression is pivotal in manipulating the genes involved in EpOME metabolism. These results indicate that NSs of TSWV are crucially linked with the elevation of host insect EpOME levels and play a key role in suppressing the antiviral responses of F. occidentalis.

Field-evolved resistance to neonicotinoids in the mosquito, Anopheles gambiae, is associated with downregulation and mutations of nicotinic acetylcholine receptor subunits combined with cytochrome P450-mediated detoxification.

Neonicotinoid insecticides act selectively on their nicotinic receptor targets leading to variable sensitivity among arthropods. This study aimed to investigate the molecular mechanisms underlying contrasting susceptibility to neonicotinoids observed in wild populations of two mosquito sibling species. Bioassays and a synergism test revealed that the sister taxa, Anopheles gambiae and An. coluzzii, from Yaounde, Cameroon, rely on cytochrome P450s to detoxify neonicotinoids and develop resistance. However, contrary to An. coluzzii, An. gambiae populations are evolving stronger resistance to several active ingredients facilitated by mutations and reduced expression of nicotinic acetylcholine receptors. Six mutations were detected in coding sequences of the β1 and α6 subunits, including two substitutions in one of the loops that modulate ligand binding and sensitivity. Allele frequencies were strongly correlated with a susceptibility gradient between An. coluzzii and An. gambiae suggesting that the mutations may play a key role in sensitivity. Messenger RNA expression levels of the β1, α3, and α7 subunits decreased dramatically, on average by 23.27, 17.50, 15.80-fold, respectively, in wild An. gambiae populations compared to a susceptible insectary colony. By contrast, only the β2 and α9-1 subunits were moderately downregulated (5.28 and 2.67-fold change, respectively) in field-collected An. coluzzii adults relative to susceptible colonized mosquitoes. Our findings provide critical information for the application and resistance management of neonicotinoids in malaria prevention.

Transcriptome analysis reveals mechanisms of metabolic detoxification and immune responses following farnesyl acetate treatment in Metisa plana

Metisa plana is a widespread insect pest infesting oil palm plantations in Malaysia. Farnesyl acetate (FA), a juvenile hormone analogue, has been reported to exert in vitro and in vivo insecticidal activity against other insect pests. However, the insecticidal mechanism of FA on M. plana remains unclear. Therefore, this study aims to elucidate responsive genes in M. plana in response to FA treatment. The RNA-sequencing reads of FA-treated M. plana were de novo-assembled with existing raw reads from non-treated third instar larvae, and 55,807 transcripts were functionally annotated to multiple protein databases. Several insecticide detoxification-related genes were differentially regulated among the 321 differentially expressed transcripts. Cytochrome P450 monooxygenase, carboxylesterase, and ATP-binding cassette protein were upregulated, while peptidoglycan recognition protein was downregulated. Innate immune response genes, such as glutathione S-transferases, acetylcholinesterase, and heat shock protein, were also identified in the transcriptome. The findings signify that changes occurred in the insect’s receptor and signaling, metabolic detoxification of insecticides, and immune responses upon FA treatment on M. plana. This valuable information on FA toxicity may be used to formulate more effective biorational insecticides for better M. plana pest management strategies in oil palm plantations.

Biochemical and molecular characterization of pyrifluquinazon resistance in Bemisia tabaci Asia I

One of the most devastating polyphagous pests in the world, Bemisia tabaci (Gennadius), causes significant damage to a variety of crops and has demonstrated the ability to develop resistance to different classes of insecticides rapidly. A novel pyridine azomethine derivative pyrifluquinazon exhibits exceptional insecticidal toxicity against B. tabaci by interrupting the function of chordotonal receptor neurons. Formulating resistance management strategies is crucial to ensure the long-term use of this insecticide for whitefly control; however, the characteristics and possible mechanisms of pyrifluquinazon resistance in B. tabaci remain unclear. By employing pyrifluquinazon selection for 22 successive generations, the pyrifluquinazon-resistant strain (PQZ-R) was generated from a laboratory-susceptible population of B. tabaci Asia I (Lab-WB) and exhibited 39.65-fold resistance to pyrifluquinazon. When the realized heritability (h2) of B. tabaci to pyrifluquinazon was assumed to be the laboratory-estimated value (h2 = 0.181) and the mortality was 70–90%, only 12.3–22.6 generations were expected to be required to obtain a 10-fold increase in pyrifluquinazon resistance. While there was no significant cross-resistance to cyantraniliprole, dinotefuran, flonicamid, flupyradifurone, pymetrozine, sulfoxaflor, or thiamethoxam, the PQZ-R strain displayed slight cross-resistance to afidopyropen (3.14-fold). Synergism tests indicated that piperonyl butoxide (PBO) inhibits (4.36-fold) pyrifluquinazon resistance in the PQZ-R strain. This impact may be attributed to enhanced detoxification (elevated 3.91-fold) mediated by cytochrome P450 monooxygenase (P450). Compared to Lab-WB, the PQZ-R strain exhibited no significant overexpression of the 13 published detoxification-related P450 genes from CYP303, CYP4, and CYP6 families in B. tabaci. The combined knowledge gained from this study will enable further investigations into the function of qualitative and quantitative variations in P450-encoded genes, leading to innovative approaches for efficiently managing B. tabaci.

Identification and in vivo functional analysis of furanocoumarin-responsive cytochrome P450s in a Rutaceae-feeding Papilio butterfly.

The Order Lepidoptera contains nearly 160,000 described species and most of them are specialist herbivores that use restricted plant species as hosts. Speciation that originated from host shift is one of the important factors for the diversification of Lepidoptera. Because plants prepare secondary metabolites for defense against herbivores, with varying profiles of the components among different plant taxa, the specialist herbivores need to be adapted to the toxic substances unique to their host plants. Swallowtail butterflies of the genus Papilio consist of over 200 species. Approximately 80% of them utilize Rutaceae plants, and among the remaining species, a specific subgroup uses phylogenetically distant Apiaceae plants as larval hosts. Rutaceae and Apiaceae commonly contain toxic secondary metabolites, furanocoumarins, and molecular phylogenetic studies support the concept that Apiaceae feeders were derived from Rutaceae feeders. Molecular mechanisms underlying furanocoumarin tolerance in Papilio butterflies have been investigated almost exclusively in an Apiaceae feeder by an in vitro assay. In contrast, there is little information regarding the Rutaceae feeders. Here, we focused on a Rutaceae feeder, Papilio xuthus, and identified two furanocoumarin-responsive cytochrome P450-6B (CYP6B) genes, of which one was an ortholog of a furanocoumarin-metabolizing enzyme identified in the Apiaceae-feeding Papilio while the other was previously unreported. We further conducted in vivo functional analysis using the CRISPR/Cas9 system, revealing a contribution of these CYP6Bs to furanocoumarin tolerance of P. xuthus larvae. Our findings suggest that co-option of furanocoumarin-metabolizing CYP6B enzymes at least partially contributed to the host shift from Rutaceae to Apiaceae in Papilio butterflies.

A P450 superfamily member NtCYP82C4 promotes nicotine biosynthesis in Nicotiana tabacum

In plants, cytochrome P450s are monooxygenase that play key roles in the synthesis and degradation of intracellular substances. In tobacco, the majority of studies examining the P450 superfamily have concentrated on the CYP82E subfamily, where multiple family members function as demethylases, facilitating the synthesis of nornicotine. In this study, NtCYP82C4, a tobacco P450 superfamily member, was identified from a gene-edited tobacco mutant that nicotine biosynthesis in tobacco leaves is evidently reduced. Compared to the wild-type plants, the knockout of NtCYP82C4 resulted in a significantly lower nicotine content and biomass in tobacco leaves. Transcriptome and metabolome analyses indicated that the knockout of NtCYP82C4 inhibites secondary metabolic processes in tobacco plants, leading to the accumulation of some important precursors in the nicotine synthesis process, including aspartic acid and nicotinic acid, and increases nitrogen partitioning associated with those processes such as amino acid synthesis and utilization. It is speculated that NtCYP82C4 may function as an important catalase downstream of the nicotine synthesis. Currently, most of the steps and enzymes involved in the nicotine biosynthesis process in tobacco have been elucidated. Here, our study deepens the current understanding of nicotine biosynthesis process and provides new enzyme targets for nicotine synthesis in tobacco plants.

Metabolism of 2,4-D in plants: comparative analysis of metabolic detoxification pathways in tolerant crops and resistant weeds.

The commercialization of 2,4-D (2,4-dichlorophenoxyacetic acid) latifolicide in 1945 marked the beginning of the selective herbicide market, with this active ingredient playing a pivotal role among commercial herbicides due to the natural tolerance of monocots compared with dicots. Due to its intricate mode of action, involving interactions within endogenous auxin signaling networks, 2,4-D was initially considered a low-risk herbicide to evolve weed resistance. However, the intensification of 2,4-D use has contributed to the emergence of 2,4-D-resistant broadleaf weeds, challenging earlier beliefs. This review explores 2,4-D tolerance in crops and evolved resistance in weeds, emphasizing an in-depth understanding of 2,4-D metabolic detoxification. Nine confirmed 2,4-D-resistant weed species, driven by rapid metabolism, highlight cytochrome P450 monooxygenases in Phase I and glycosyltransferases in Phase II as key enzymes. Resistance to 2,4-D may also involve impaired translocation associated with mutations in auxin/indole-3-acetic acid (Aux/IAA) co-receptor genes. Moreover, temperature variations affect 2,4-D efficacy, with high temperatures increasing herbicide metabolism rates and reducing weed control, while drought stress did not affect 2,4-D efficacy. Research on 2,4-D resistance has primarily focused on non-target-site resistance (NTSR) mechanisms, including 2,4-D metabolic detoxification, with limited exploration of the inheritance and genetic basis underlying these traits. Resistance to 2,4-D in weeds is typically governed by a single gene, either dominant or incompletely dominant, raising questions about gain-of-function or loss-of-function mutations that confer resistance. Future research should unravel the physiological and molecular-genetic basis of 2,4-D NTSR, exploring potential cross-resistance patterns and assessing fitness costs that may affect future evolution of auxin-resistant weeds. © 2024 Society of Chemical Industry.

Chiral Bioelectrocatalytic Oxidations Driven By Electrocatalytic Oxygen Reduction and Horseradish Peroxidase or Cytochrome P450

Biocatalysis, the use of enzymes for synthesis, has emerged as a powerful tool for synthesis of chiral molecules in pharmaceutical and fine chemical industries. Natural enzymes offer inherent stereoselectivity, making them attractive catalysts for this purpose. Peroxidases and cytochrome P450s enzymes utilize an iron-heme cofactor to perform a diverse array of chemical transformations including CH2 hydroxylation, epoxidations, and sulfur-oxidations. Here, we report chiral biocatalytic oxidations in microemulsion media driven by horseradish peroxidase (HRP) coupled with a synthetic Cu2+-polymer electrocatalyst to convert O2 to H2O2. This tandem system uses crosslinked layer-by-layer (LBL) films of polyelectrolytes with Cu2+- poly(2-hydroxy-3-dipicolylamino) propyl methacrylate (Py-PGMADPA) to drive O2 reduction. Peroxide in turn activates HRP crosslinked in LbL films on magnetic beads (MB) to biocatalytically oxidize styrene, ethylbenzene, and methyl phenylacetate to chiral products. R-stereoisomers of these reactants were selectively formed with a high enantiomeric excess of > 80%. Conductive microemulsion reaction media are used to provide solubility to the non-polar reactants and water to hydrate the enzymes to function. The enzyme films show high thermal stability and high chiral selectivity up to 90 °C. A second synthetic goal was to compare chiral products of reactions catalyzed by cyt P450’s natural catalytic pathway mimicked by electrocatalysis versus via electrochemical generation of H2O2. We immobilized baculosome-P450s in LBL films with polystyrene sulfonate for the natural catalytic pathway, and for peroxide activation crosslinked P450 LbL on magnetic beads. These synthetic hybrid approaches open new doors to designing biocatalytic syntheses using an electrochemical driving force. Keywords: Biocatalysis, organic syntheses, cytochrome P450, horseradish peroxidase, regioselective and stereoselective oxidation

Dietary oxyclozanide influences antioxidant enzyme activities and damages DNA in Galleria mellonella (Lepidoptera: Pyralidae).

Oxyclozanide (OXY) is an anthelmintic widely used in the treatment of flatworm infection and fasciolosis. It also has antiadenovirus, antibiofilm, antifungal, and antibacterial activities. Various chemicals have been suggested as alternative chemicals in insect pest management. Here, the oxidative and genotoxic effects of OXY on 7th instars, pupae and adults of the model organism Galleria mellonella (Linnaeus) (Lepidoptera: Pyralidae) were examined. First-instar larvae were reared on 0.003, 0.03, 0.3, and 1.5 g OXY per 100 g artificial diets. Compared with all tested OXY concentrations and controls without OXY, dietary OXY led to increased antioxidant capacity and genotoxic effects. Concentrations of malondialdehyde, an oxidative stress marker, were significantly increased in adults of larvae reared on OXY-charged diets at 0.3 and 1.5 g/100 g compared to the adult control group. We also recorded a significant increase in the genotoxic test data (Tail length, Tail DNA %, Tail moment) at the same stages and concentrations. We recorded significant increases in glutathione-S-transferase, superoxide dismutase (SOD) and glutathione peroxidase activities in larvae fed high OXY concentrations. SOD and catalase activities were also significantly increased at the concentration of 0.03 g/100 g of OXY in the pupal and adult stages. Cytochrome P450 monooxygenase activity was significantly increased at the highest concentration of OXY in the larval and pupal stages. Also, our regression analysis indicates a correlation between the markers of oxidative stress, antioxidant enzymes and comet parameters. These data indicate that OXY induces oxidative stress and antioxidative enzyme response.

Qualitative and quantitative status of cytochrome P450s after the administration of a liposomal platelet substitute in rat liver

In the process of the drug development, studies on the cytochrome P450 (CYP) profiles after its administration provided fundamental information regarding drug interactions with concomitantly administered drugs. Here, we evaluated the influence of the administration of H12-(ADP)-liposomes, a platelet substitute, on the mRNA and protein expression, and metabolic activity of CYPs, with focus on the CYP1A2, CYP2C11 and CYP3A2, in rat liver. At 24 h after administering saline or H12-(ADP)-liposomes (10 mg of lipids/kg), a quantitative RT-PCR and western blot analysis revealed that the mRNA and proteins expression of all of the target hepatic CYP isoforms were not different between the saline and H12-(ADP)-liposome groups. Furthermore, an ex vivo CYP metabolic activity assay showed that hepatic CYP metabolic activities in the H12-(ADP)-liposome group were comparable to the corresponding saline group. On the other hand, the area under the blood concentration-time curve for substitutes for CYP1A2 and CYP2C11 was higher in H12-(ADP)-liposome group than in saline group, but the degree of elevations was negligible levels. At a minimum, based on these results, we conclude that H12-(ADP)-liposomes have no quantitative and qualitative effect on the hepatic CYP isoforms, indicating that the drug interactions of H12-(ADP)-liposomes with CYP-metabolizing drugs would be negligible.

Aryl hydrocarbon receptor-dependent toxicity by retene requires metabolic competence.

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds frequently detected in the environment with widely varying toxicities. Many PAHs activate the aryl hydrocarbon receptor (AHR), inducing the expression of a battery of genes, including xenobiotic metabolizing enzymes like cytochrome P450s (CYPs); however, not all PAHs act via this mechanism. We screened several parent and substituted PAHs in in vitro AHR activation assays to classify their unique activity. Retene (1-methyl-7-isopropylphenanthrene) displays Ahr2-dependent teratogenicity in zebrafish, but did not activate human AHR or zebrafish Ahr2, suggesting a retene metabolite activates Ahr2 in zebrafish to induce developmental toxicity. To investigate the role of metabolism in retene toxicity, studies were performed to determine the functional role of cyp1a, cyp1b1, and the microbiome in retene toxicity, identify the zebrafish window of susceptibility, and measure retene uptake, loss, and metabolite formation in vivo. Cyp1a-null fish were generated using CRISPR-Cas9. Cyp1a-null fish showed increased sensitivity to retene toxicity, whereas Cyp1b1-null fish were less susceptible, and microbiome elimination had no significant effect. Zebrafish required exposure to retene between 24 and 48 hours post fertilization (hpf) to exhibit toxicity. After static exposure, retene concentrations in zebrafish embryos increased until 24 hpf, peaked between 24 and 36 hpf, and decreased rapidly thereafter. We detected retene metabolites at 36 and 48 hpf, indicating metabolic onset preceding toxicity. This study highlights the value of combining molecular and systems biology approaches with mechanistic and predictive toxicology to interrogate the role of biotransformation in AHR-dependent toxicity.

Lambda-cyhalothrin induces heart injury in chickens by regulating cytochrome P450 enzyme system and inhibiting Nrf2/HO-1 pathway

Lambda-cyhalothrin (LCT) is a common pyrethroid insecticide widely used for ectoparasite control and hygiene pest prevention in poultry and this study aimed to investigate the mechanisms of LCT-induced cardiac injury in chickens. Low, medium, and high-dose LCT exposure models in chickens were established and hematoxylin and eosin (H&E) staining, dihydroethidium (DHE) staining, TUNEL staining, immunofluorescence, biochemical analysis, and gene expression analysis were used to study the effects of LCT exposure on the chicken heart. The results showed that LCT exposure increased the serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH), led to muscle fiber breakage and inflammatory cell infiltration and caused cardiac tissue damage. The DHE staining and biochemical analysis revealed that LCT exposure resulted in the excessive accumulation of ROS, decreased activities/levels of catalase (CAT), total superoxide dismutase (T-SOD), and glutathione (GSH), and increased levels of the oxidative damage marker malondialdehyde (MDA). The TUNEL staining indicated that LCT exposure increased apoptosis possibly through the elevated expression of pro-apoptotic genes in the mitochondrial pathway, the reduced expression of anti-apoptotic genes, the upregulation of pro-inflammatory factors and the downregulation of anti-inflammatory factors. Here, LCT exposure significantly inhibited the expression of genes in the Nrf2/HO-1 pathway and activated the expression of genes in the CYP450 enzyme system. Compared to the low-dose group, the high-dose LCT exposure group showed lower levels of apoptosis and inflammation, possibly related to the low oxidative stress levels mediated by the decreased expression of the CYP450 enzyme system. In conclusion, LCT exposure induces oxidative stress, apoptosis, and inflammation in chicken hearts, which may be associated with the inhibition of the Nrf2/HO-1 pathway and activation of the CYP450 enzyme system. This study provides a theoretical basis for the safer use of insecticides in poultry production.

Cadmium causes spleen toxicity in chickens by regulating mitochondrial unfolded protein response and nuclear receptors response

Cadmium (Cd) is a heavy metal that pollutes the environment and threatens human and animal health via the food chain. The spleen is one of the target organs affected by Cd toxicity. However, the mechanism of Cd toxicity is not fully understood. In this study, 80 chicks were allocated into 4 groups (n = 20) and exposed to different doses of CdCl2 (0 mg/kg, 35 mg/kg, 70 mg/kg and 140 mg/kg) for 90 d. The pathological changes in the spleen, mitochondrial dynamics-related factors, cytochrome P450 (CYP450) enzyme system contents, activities, transcription levels, nuclear receptors (NRs) response molecule levels, and mitochondrial unfolded protein-related factors were detected. The findings indicate that exposure to Cd significantly leads to spleen injury. In Cd groups, the total contents of CYP450 and cytochrome b5 (Cyt b5) increased, and the activities of the CYP450 enzyme system (APND, ERND, AH, and NCR) changed. The NRs response was induced, and the gene levels of AHR/CAR and corresponding CYP450 isoforms (CYP1B1, CYP1A5, CYP1A1, CYP2C18, CYP2D6 and CYP3A4) were found altered. The study found that Cd exposure altered the mRNA expression levels of mitochondrial dynamics-related factors, such as OPA1, Fis1, MFF, Mfn1, and Mfn2, breaking mitochondrial fusion and cleavage and ultimately leading to mitochondrial dysfunction. Changes were detected in the gene levels of several mitochondrial unfolded protein response (mtUPR)-related factors, namely (SIRT1, PGC-1α, NRF1, TFAM, SOD2, and HtrA2). Cd also altered the gene levels of mitochondrial function-related factors (VDAC1, Cyt-C, COA6, PRDX3, RAF and SIRT3). It is showed that Cd can initiate the NRs response, influence the homeostasis of the CPY450 enzyme system, trigger the mtUPR, impair mitochondrial function, and ultimately lead to Cd toxicity in the spleen of chickens.

The Comparative Metabolism of a Novel Hepatocellular Carcinoma Therapeutic Agent, 2,3-Diamino-N-(4-(benzo[d]thiazol-2-yl)phenyl)propanamide, in Human and Animal Hepatocytes.

[2,3-diamino-N-(4-(benzo[d]thiazol-2-yl)phenyl)propanamide], named as ETN101, is a novel therapeutic agent for hepatocellular carcinoma. In vitro studies examined ETN101 metabolites in human, mouse, rat, dog, and monkey hepatocytes and identified the drug-metabolizing enzymes involved using cDNA-expressed human recombinant cytochrome P450s (CYPs), carboxylesterases (CESs), N-acetyltransferase (NAT) 1, and human liver cytosol. ETN101 showed similar metabolic stability across hepatocytes from five species, with particularly comparable stability in humans, rats, and monkeys. Its half-life was 75.0 min in humans, 68.9 in rats, 73.1 in monkeys, 120.4 in mice, and 112.7 in dogs. Thirty-four ETN101 metabolites, including the major metabolite M1, were identified using liquid chromatography-high-resolution mass spectrometry. ETN101 was primarily metabolized to M1 and CYP1A2 is exclusively responsible for M1 metabolism. Both NAT1 and NAT2 were responsible for the N-acetylation of M1 to M2. ETN101 remained stable in human CESs. In conclusion, this study provides comprehensive insights into the metabolic characteristics of ETN101, valuable for its toxicological and clinical development.

Fumonisin B1 induces endoplasmic reticulum damage and inflammation by activating the NXR response and disrupting the normal CYP450 system, leading to liver damage in juvenile quail.

Fumonisin B1 (FB1) is a mycotoxin affecting animal health through the food chain and has been closely associated with several diseases such as pulmonary edema in pigs and diarrhea in poultry. FB1 is mainly metabolized in the liver. Although a few studies have shown that FB1 causes liver damage, the molecular mechanism of liver damage is unclear. This study aimed to evaluate the role of liver damage, nuclear xenobiotic receptor (NXR) response and cytochrome P450 (CYP450)-mediated defense response during FB1 exposure. A total of 120 young quails were equally divided into two groups (control and FB1 groups). The quails in the control group were fed on a normal diet, while those in the FB1 group were fed on a quail diet containing 30mg/kg for 42 days. Histopathological and ultrastructural changes in the liver, biochemical parameters, inflammatory factors, endoplasmic reticulum (ER) factors, NXR response and CYP450 cluster system and other related genes were examined at 14 days, 28 days and 42 days. The results showed that FB1 exposure impaired the metabolic function and caused liver injury. FB1 caused ER stress and decreased adenosine triphosphatease activity, induced the expression of inflammation-related genes such as interleukin 6 and nuclear factor kappa-B, and promoted inflammation. In addition, FB1 disrupted the expression of multiple CYP450 isoforms by activating nuclear xenobiotic receptors (NXRs). The present study confirms that FB1 exposure disturbs the homeostasis of cytochrome P450 systems (CYP450s) in quail liver by activating NXR responses and thereby causing liver damage. This study's findings provide insight into the molecular mechanisms of FB1-induced hepatotoxicity.

Treatment outcomes and CYP3A4*1G genotype distribution in children with peptic ulcers

Many factors, including the role of the cytochrome P450 system such as CYP3A4*1G, may influence the effectiveness of peptic ulcer treatment. The study aimed to describe the treatment outcomes and distribution of CYP3A4*1G genotype in children with peptic ulcers. A descriptive cross-sectional study, longitudinal follow-up before and after six weeks of treatment was conducted on 100 children with peptic ulcers from October 2022 to February 2024. Children with peptic ulcers without H. pylori infection had a higher rate of anemia, and pyloric and duodenal deformation, compatible with children with H. pylori. The ulcer healing rate was lower in children with deep peptic ulcers, excess eosinophils in mucosal biopsies, and poor therapeutic compliance. The distribution of CYP3A4*1/*1, CYP3A4*1/CYP3A4*1G, CYP3A4*1G/CYP3A4*1G in the study was 43.2%, 48.1%, and 8.6%, respectively, with no difference by gender. There were no difference in ulcer healing rates according to the presence of the CYP3A4*1G variant. In conclusion, the degree of peptic ulcer healing in children varies according to several characteristics. However, there were no difference in ulcer healing rates according to the presence of the CYP3A4*1G variant.

A cytochrome P450 monooxygenase (CYP337B5) plays a key role in regulating juvenile hormone biosynthesis and degrading chlorantraniliprole in Spodoptera frugiperda (Lepidoptera: Noctuidae)

Cytochrome P450 monooxygenase (P450) has been shown to be involved in the detoxification metabolism of exogenous drugs or regulates the endogenous synthesis of juvenile hormone III (JH III). However, it is not yet known whether a particular P450 gene involved in the metabolism also affects the synthesis of juvenile hormones. Fall armyworm (FAW, Spodoptera frugiperda) showed a significant increase in juvenile hormone I (JH I) and juvenile hormone II (JH II) under chlorantraniliprole stress, and 11 chlorantraniliprole resistance-related P450 genes were significantly up-regulated. Among them, CYP337B5 was not only overexpressed in the midgut and head of FAW larvae, but also significantly increased in the female and male adult stages with high JH I and JH II titers. Injecting double-stranded RNA significantly reduced the metabolism rate of chlorantraniliprole in FAW and inhibited the production of juvenile hormones. Additionally, the degradation rates of chlorantraniliprole were significantly increased along with the production of various metabolites when incubated in vitro using recombinant CYP337B5; and JH I and JH II were also increased to some extent by 1.2 and 0.5 times. The results show that CYP337B5 is efficiently involved in the metabolism of chlorantraniliprole and specifically involved in the synthesis of JH I and JH II. We show that some P450s may have dual functions of endogenous hormone synthesis and exogenous substance metabolism in insects, which may be the root cause of the cost of drug resistance in insects.

Unraveling the role of cytochrome P450 enzymes in oleanane triterpenoid biosynthesis in arjuna tree.

Triterpenoids (C30-isoprenoids) represent a major group of natural products with various physiological functions in plants. Triterpenoids and their derivatives have medicinal uses owing to diverse bioactivities. Arjuna (Terminalia arjuna) tree bark accumulates highly oxygenated β-amyrin-derived oleanane triterpenoids (e.g., arjunic acid, arjungenin, and arjunolic acid) with cardioprotective roles. However, biosynthetic routes and enzymes remain poorly understood. We mined the arjuna transcriptome and conducted cytochrome P450 monooxygenase (P450) assays using Saccharomyces cerevisiae and Nicotiana benthamiana to identify six P450s and two P450 reductases for oxidative modifications of oleanane triterpenoids. P450 assays using oleananes revealed a greater substrate promiscuity of C-2α and C-23 hydroxylases/oxidases than C-28 oxidases. CYP716A233 and CYP716A432 catalyzed β-amyrin/erythrodiol C-28 oxidation to produce oleanolic acid. C-2α hydroxylases (CYP716C88 and CYP716C89) converted oleanolic acid and hederagenin to maslinic acid and arjunolic acid. CYP716C89 also hydroxylated erythrodiol and oleanolic aldehyde. However, CYP714E107a and CYP714E107b catalyzed oleanolic acid/maslinic acid/arjunic acid, C-23 hydroxylation to form hederagenin, arjunolic acid and arjungenin, and hederagenin C-23 oxidation to produce gypsogenic acid, but at a lower rate than oleanolic acid C-23 hydroxylation. Overall, P450 substrate selectivity suggested that C-28 oxidation is the first P450-catalyzed oxidative modification in the arjuna triterpenoid pathway. However, the pathway might branch thereafter through C-2α/C-23 hydroxylation of oleanolic acid. Taken together, these results provided new insights into substrate range of P450s and unraveled biosynthetic routes of triterpenoids in arjuna. Moreover, complete elucidation and reconstruction of arjunolic acid pathway in S. cerevisiae and N. benthamiana suggested the utility of arjuna P450s in heterologous production of cardioprotective compounds.

Insights into the biodegradation of fipronil through soil microcosm-omics analyses of Pseudomonas sp. FIP_ A4

Fipronil, a phenylpyrazole insecticide, is used to kill insects resistant to conventional insecticides. Though its regular and widespread use has substantially reduced agricultural losses, it has also caused its accumulation in various environmental niches. The biodegradation is an effective natural process that helps in reducing the amount of residual insecticides. This study deals with an in-depth investigation of fipronil degradation kinetics and pathways in Pseudomonas sp. FIP_A4 using multi-omics approaches. Soil-microcosm results revealed ∼87% degradation within 40 days. The whole genome of strain FIP_A4 comprises 4.09 Mbp with 64.6% GC content. Cytochrome P450 monooxygenase and enoyl-CoA hydratase-related protein, having 30% identity with dehalogenase detected in the genome, can mediate the initial degradation process. Proteome analysis revealed differential enzyme expression of dioxygenases, decarboxylase, and hydratase responsible for subsequent degradation. Metabolome analysis displayed fipronil metabolites in the presence of the bacterium, supporting the proposed degradation pathway. Molecular docking and dynamic simulation of each identified enzyme in complex with the specific metabolite disclosed adequate binding and high stability in the enzyme-metabolite complex. This study provides in-depth insight into genes and their encoded enzymes involved in the fipronil degradation and formation of different metabolites during pollutant degradation. The outcome of this study can contribute immensely to developing efficient technologies for the bioremediation of fipronil-contaminated soils.

Roles of cytochrome P450 monooxygenases in triterpene biosynthesis and their potential impact on growth and development.

Pentacyclic triterpenoids, recognized for their natural bioactivity, display complex spatiotemporal accumulation patterns within the ecological model plant Nicotiana attenuata. Despite their ecological importance, the underlying biosynthetic enzymes and functional attributes of triterpenoid synthesis in N. attenuata remain unexplored. Here, we show that three cytochrome P450 monooxygenases (NaCYP716A419, NaCYP716C87, and NaCYP716E107) from N. attenuata oxidize the pentacyclic triterpene skeleton, as evidenced by heterologous expression in Nicotiana benthamiana. NaCYP716A419 catalyzed a consecutive three-step oxidation reaction at the C28 position of β-amyrin/lupeol/lupanediol, yielding the corresponding alcohol, aldehyde, and carboxylic acid. NaCYP716C87 hydroxylated the C2α position of β-amyrin/lupeol/lupanediol/erythrodiol/oleanolic acid/betulinic acid, while NaCYP716E107 hydroxylated the C6β position of β-amyrin/oleanolic acid. The genes encoding these three CYP716 enzymes are highly expressed in flowers and respond to induction by ABA, MeJA, SA, GA3, and abiotic stress treatments. Using VIGS technology, we revealed that silencing of NaCYP716A419 affects the growth and reproduction of N. attenuata, suggesting the ecological significance of these specialized metabolite biosynthetic steps.