iRhom2 is essential for innate immunity to DNA viruses by mediating trafficking and stability of the adaptor STING.

STING is a central adaptor in the innate immune response to DNA viruses. However, the manner in which STING activity is regulated remains unclear. We identified iRhom2 ('inactive rhomboid protein 2') as a positive regulator of DNA-virus-triggered induction of type I interferons. iRhom2 deficiency markedly impaired DNA-virus- and intracellular-DNA-induced signaling in cells, and iRhom2-deficient mice were more susceptible to lethal herpes simplex virus type 1 (HSV-1) infection. iRhom2 was constitutively associated with STING and acted in two distinct processes to regulate STING activity. iRhom2 recruited the translocon-associated protein TRAPß to the STING complex to facilitate trafficking of STING from the endoplasmic reticulum to perinuclear microsomes. iRhom2 also recruited the deubiquitination enzyme EIF3S5 to maintain the stability of STING through removal of its K48-linked polyubiquitin chains. These results suggest that iRhom2 is essential for STING activity, as it regulates TRAPß-mediated translocation and EIF3S5-mediated deubiquitination of STING.

Structure of the Inhibited State of the Sec Translocon.

Protein secretion in eukaryotes and prokaryotes involves a universally conserved protein translocation channel formed by the Sec61 complex. Unrelated small-molecule natural products and synthetic compounds inhibit Sec61 with differential effects for different substrates or for Sec61 from different organisms, making this a promising target for therapeutic intervention. To understand the mode of inhibition and provide insight into the molecular mechanism of this dynamic translocon, we determined the structure of mammalian Sec61 inhibited by the Mycobacterium ulcerans exotoxin mycolactone via electron cryo-microscopy. Unexpectedly, the conformation of inhibited Sec61 is optimal for substrate engagement, with mycolactone wedging open the cytosolic side of the lateral gate. The inability of mycolactone-inhibited Sec61 to effectively transport substrate proteins implies that signal peptides and transmembrane domains pass through the site occupied by mycolactone. This provides a foundation for understanding the molecular mechanism of Sec61 inhibitors and reveals novel features of translocon function and dynamics.

Stepwise insertion and inversion of a type II signal anchor sequence in the ribosome-Sec61 translocon complex.

In eukaryotic cells, the ribosome-Sec61 translocon complex (RTC) establishes membrane protein topology by cotranslationally partitioning nascent polypeptides into the cytosol, ER lumen, and lipid bilayer. Using photocrosslinking, collisional quenching, cysteine accessibility, and protease protection, we show that a canonical type II signal anchor (SA) acquires its topology through four tightly coupled and mechanistically distinct steps: (1) head-first insertion into Sec61α, (2) nascent chain accumulation within the RTC, (3) inversion from type I to type II topology, and (4) stable translocation of C-terminal flanking residues. Progression through each stage is induced by incremental increases in chain length and involves abrupt changes in the molecular environment of the SA. Importantly, type II SA inversion deviates from a type I SA at an unstable intermediate whose topology is controlled by dynamic interactions between the ribosome and translocon. Thus, the RTC coordinates SA topogenesis within a protected environment via sequential energetic transitions of the TM segment.

A novel system to determine activity of individual uridine 5'-diphospho-glucuronosyltransferase (UGT) isoforms: Recombinant UGT-beads.

Previous work demonstrated that human liver microsomes (HLMs) can spontaneously bind to silica-coated magnetizable beads (HLM-beads) and that these HLM-beads retain uridine 5'-diphospho-glucuronosyltransferase (UGT) activity. However, the contributions of individual UGT isoforms are not directly assessable in this system except through use of model inhibitors. Thus, a preparation wherein recombinant UGT (rUGT) microsomes bound to these same beads to form rUGT-beads of individual UGT isoforms would provide a novel system for measuring the contribution of individual UGT isoforms in a direct manner. To this end, the enzyme activities and kinetic parameter estimates of various rUGT isoforms in rUGT-beads were investigated, as well as the impact of fatty acids (FAs) on enzyme activity. The catalytic efficiencies (Vmax/Km) of the tested rUGTs were twofold to sevenfold higher in rUGT-beads compared with rUGT microsomes, except for rUGT1A6, where Vmax is the maximum product formation rate normalized to milligram of microsomal protein (pmol/min/mg protein). Interestingly, in contrast to traditional rUGT preparations, the sequestration of UGT-inhibitory FA using bovine serum albumin did not alter the catalytic efficiency (Vmax/Km) of the rUGTs in rUGT-beads. Moreover, the increase in catalytic efficiency of rUGT-beads over rUGT microsomes was similar to increases in catalytic efficiency noted with rUGT microsomes (not bound to beads) incubated with bovine serum albumin, suggesting the beads in some way altered the potential for FAs to inhibit activity. The rUGT-bead system may serve as a useful albumin-free tool to determine kinetic constants for UGT substrates, particularly those that exhibit high binding to albumin.

Identification and Functional Assessment of Eight CYP3A4 Allelic Variants *39-*46 Detected in the Chinese Han Population.

Cytochrome P450 3A4 (CYP3A4), a key enzyme, is pivotal in metabolizing approximately half of the drugs used clinically. The genetic polymorphism of the CYP3A4 gene significantly influences individual variations in drug metabolism, potentially leading to severe adverse drug reactions (ADRs). In this study, we conducted a genetic analysis on CYP3A4 gene in 1163 Chinese Han individuals to identify the genetic variations that might affect their drug metabolism capabilities. For this purpose, a multiplex polymerase chain reaction (PCR) amplicon sequencing technique was developed, enabling us to perform the genotyping of CYP3A4 gene efficiently and economically on a large scale. As a result, a total of 14 CYP3A4 allelic variants were identified, comprising six previously reported alleles and eight new nonsynonymous variants that were nominated as new allelic variants *39-*46 by the PharmVar Association. Further, functional assessments of these novel CYP3A4 variants were undertaken by coexpressing them with cytochromes P450 oxidoreductase (CYPOR) in Saccharomyces cerevisiae microsomes. Immunoblot analysis indicated that with the exception of CYP3A4.40 and CYP3A4.45, the protein expression levels of most new variants were similar to that of the wild-type CYP3A4.1 in yeast cells. To evaluate their catalytic activities, midazolam was used as a probe drug. The results showed that variant CYP3A4.45 had almost no catalytic activity, whereas the other variants exhibited significantly reduced drug metabolism abilities. This suggests that the majority of the CYP3A4 variants identified in the Chinese population possess markedly altered capacities for drug metabolism. SIGNIFICANCE STATEMENT: In this study, we established a multiplex polymerase chain reaction (PCR) amplicon sequencing method and detected the maximum number of new CYP3A4 variants in a single ethnic population. Additionally, we performed the functional characterizations of these eight novel CYP3A4 allele variants in vitro. This study not only contributes to the understanding of CYP3A4 genetic polymorphism in the Chinese Han population but also holds substantial reference value for their potential clinical applications in personalized medicine.

Tissue-, Region-, and Gene-Specific Induction of Microsomal Epoxide Hydrolase Expression and Activity in the Mouse Intestine by Arsenic in Drinking Water.

This study aimed to characterize the effects of arsenic exposure on the expression of microsomal epoxide hydrolase (mEH or EPHX1) and soluble epoxide hydrolase (sEH or EPHX2) in the liver and small intestine. C57BL/6 mice were exposed to sodium arsenite in drinking water at various doses for up to 28 days. Intestinal, but not hepatic, mEH mRNA and protein expression was induced by arsenic at 25 ppm, in both males and females, whereas hepatic mEH expression was induced by arsenic at 50 or 100 ppm. The induction of mEH was gene specific, as the arsenic exposure did not induce sEH expression in either tissue. Within the small intestine, mEH expression was induced only in the proximal, but not the distal segments. The induction of intestinal mEH was accompanied by increases in microsomal enzymatic activities toward a model mEH substrate, cis-stilbene oxide, and an epoxide-containing drug, oprozomib, in vitro, and by increases in the levels of PR-176, the main hydrolysis metabolite of oprozomib, in the proximal small intestine of oprozomib-treated mice. These findings suggest that intestinal mEH, playing a major role in converting xenobiotic epoxides to less reactive diols, but not sEH, preferring endogenous epoxides as substrates, is relevant to the adverse effects of arsenic exposure, and that further studies of the interactions between drinking water arsenic exposure and the disposition or possible adverse effects of epoxide-containing drugs and other xenobiotic compounds in the intestine are warranted. SIGNIFICANCE STATEMENT: Consumption of arsenic-contaminated water has been associated with increased risks of various adverse health effects, such as diabetes, in humans. The small intestinal epithelial cells are the main site of absorption of ingested arsenic, but they are not well characterized for arsenic exposure-related changes. This study identified gene expression changes in the small intestine that may be mechanistically linked to the adverse effects of arsenic exposure and possible interactions between arsenic ingestion and the pharmacokinetics of epoxide-containing drugs in vivo.

Structure-activity relationship and mechanistic study of organotins as inhibitors of human, pig, and rat gonadal 3ß-hydroxysteroid dehydrogenases.

Organotins have been widely used in various industrial applications. This study investigated the structure-activity relationship as inhibitors of human, pig, and rat gonadal 3ß-hydroxysteroid dehydrogenases (3ß-HSD). Human KGN cell, pig, and rat testis microsomes were utilized to assess the inhibitory effects of 18 organotins on the conversion of pregnenolone to progesterone. Among them, diphenyltin, triethyltin, and triphenyltin exhibited significant inhibitory activity against human 3ß-HSD2 with IC50 values of 114.79, 106.98, and 5.40 µM, respectively. For pig 3ß-HSD, dipropyltin, diphenyltin, triethyltin, tributyltin, and triphenyltin demonstrated inhibitory effects with IC50 values of 172.00, 100.19, 87.00, 5.75, and 1.65 µM, respectively. Similarly, for rat 3ß-HSD1, dipropyltin, diphenyltin, triethyltin, tributyltin, and triphenyltin displayed inhibitory activity with IC50 values of 81.35, 43.56, 55.55, 4.09, and 0.035 µM, respectively. They were mixed inhibitors of pig and rat 3ß-HSD, while triphenyltin was identified as a competitive inhibitor of human 3ß-HSD2. The mechanism underlying the inhibition of organotins on 3ß-HSD was explored, revealing that they may disrupt the enzyme activity by binding to cysteine residues in the catalytic sites. This proposition was supported by the observation that the addition of dithiothreitol reversed the inhibition caused by all organotins except for triethyltin, which was partially reversed. In conclusion, this study provides valuable insights into the structure-activity relationship of organotins as inhibitors of human, pig, and rat gonadal 3ß-HSD. The mechanistic investigation suggests that these compounds likely exert their inhibitory effects through binding to cysteine residues in the catalytic sites.

Characterization of the 263K-derived microsomal fraction: a source of prions for nanofiltration validation studies.

BACKGROUND: The manufacturing processes of plasma products include steps that can remove prions. The efficacy of these steps is measured in validation studies using animal brain-derived prion materials called spikes. Because the nature of the prion agent in blood is not known, the relevance of these spikes, particularly with steps that are based on retention mechanisms such as nanofiltration, is important to investigate. STUDY DESIGN AND METHODS: The aggregation and sizes of PrPres assemblies of microsomal fractions (MFs) extracted from 263K-infected hamster brains were analyzed using velocity gradients. The separated gradient fractions were either inoculated to Tg7 mice expressing hamster-PrPc to measure infectivity or used in Protein Misfolding Cyclic Amplification for measuring seeding activity. The collected data allowed for reanalyzing results from previous nanofiltration validation studies. RESULTS: A significant portion of MFs was found to be composed of small PrPres assemblies, estimated to have a size ≤24 mers (~22-528 kDa), and to contain a minimum of 20% of total prion infectivity. With this data we could calculate reductions of 4.10 log (15 N), 2.53 log (35 N), and 1.77 log (35 N) from validation studies specifically for these small PrPres objects. CONCLUSION: Our gradient data provided evidence that nanofilters can remove the majority of the smallest PrPres entities within microsomes spikes, estimated to be in a size below 24 mers, giving insight about the fact that, in our conditions, size exclusion may not be the only mechanism for retention nanofiltration.

Activation of Ca2+ transport in cardiac microsomes enriches functional sets of ER and SR proteins.

The importance of sarcoplasmic reticulum (SR) Ca2+-handling in heart has led to detailed understanding of Ca2+-release and re-uptake protein complexes, while less is known about other endoplasmic reticulum (ER) functions in the heart. To more fully understand cardiac SR and ER functions, we analyzed cardiac microsomes based on their increased density through the actions of the SR Ca2+-ATPase (SERCA) and the ryanodine receptor that are highly active in cardiomyocytes. Crude cardiac microsomal vesicles loaded with Ca oxalate produced two higher density subfractions, MedSR and HighSR. Proteins from 20.0 µg of MV, MedSR, and HighSR protein were fractionated using SDS-PAGE, then trypsinized from 20 separate gel pieces, and analyzed by LC-MS/MS to determine protein content. From 62,000 individual peptide spectra obtained, we identified 1105 different proteins, of which 354 were enriched ≥ 2.0-fold in SR fractions compared to the crude membrane preparation. Previously studied SR proteins were all enriched, as were proteins associated with canonical ER functions. Contractile, mitochondrial, and sarcolemmal proteins were not enriched. Comparing the levels of SERCA-positive SR proteins in MedSR versus HighSR vesicles produced a range of SR subfraction enrichments signifying differing levels of Ca2+ leak co-localized in the same membrane patch. All known junctional SR proteins were more enriched in MedSR, while canonical ER proteins were more enriched in HighSR membrane. Proteins constituting other putative ER/SR subdomains also exhibited average Esub enrichment values (mean ± S.D.) that spanned the range of possible Esub values, suggesting that functional sets of proteins are localized to the same areas of the ER/SR membrane. We conclude that active Ca2+ loading of cardiac microsomes, reflecting the combined activities of Ca2+ uptake by SERCA, and Ca2+ leak by RyR, permits evaluation of multiple functional ER/SR subdomains. Sets of proteins from these subdomains exhibited similar enrichment patterns across membrane subfractions, reflecting the relative levels of SERCA and RyR present within individual patches of cardiac ER and SR.

Comparison of Relative Activity versus Relative Expression Factors (RAF versus REF) in Predicting Glucuronidation Mediated Drug Clearance Using Recombinant UGTs.

PURPOSE: Predicting the quantitative fraction of glucuronidation (fgluc) by individual UDP-glucuronosyltransferase enzymes (UGTs) is challenging due to the lack of selective inhibitors and inconsistent activity of recombinant UGT systems (rUGTs). Our study compares the relative expression versus activity factors (REF versus RAF) to predict fgluc based on rUGT data to human liver and intestinal microsomes (HLM and HIM). METHODS: REF scalars were derived from a previous in-house proteomics study for eleven UGT enzymes (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, UGT1A10, UGT2B4, UGT2B7, UGT2B10, UGT2B15, and UGT2B17), whereas RAF was calculated by measuring activities in rUGTs to microsomes of selective UGT probe substrates. Protein-normalized activity factor (pnAF) values were generated after correcting activity of individual UGTs to their corresponding protein abundance. The utility of REF and RAF in predicting fgluc was assessed for three UGT substrates-diclofenac, vorinostat, and raltegravir. RESULTS: The REF values ranged from 0.02 to 1.75, RAF based on activity obtained in rUGTs to HLM/HIM were from 0.1 to 274. pnAF values were ~ 5 to 80-fold, except for UGT2B4 and UGT2B15, where pnAF was ~ 180 and > 1000, respectively. The results revealed confounding effect of differential specific activities (per pmol) of rUGTs in fgluc prediction. CONCLUSION: The data suggest that the activity of UGT enzymes was significantly lower when compared to their activity in microsomes at the same absolute protein amount (pmol). Collectively, results of this study demonstrate poor and variable specific activity of different rUGTs (per pmol protein), as determined by pnAF values, which should be considered in fgluc scaling.

Novel 1,3,4-oxadiazole derivatives as highly potent microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibitors.

Selective inhibition of microsomal prostaglandin E2 synthase-1 (mPGES-1) is implicated as a new therapeutic modality for the development of new-generation anti-inflammatory drugs. Here, we present the discovery of new and potent inhibitors of human mPGES-1, i.e., compounds 13, 15-25, 29-30 with IC50 values in the range of 5.6-82.3 nM in a cell-free assay of prostaglandin (PG)E2 formation. We also demonstrate that 20 (TG554, IC50 = 5.6 nM) suppresses leukotriene (LT) biosynthesis at low µM concentrations, providing a benchmark compound that dually intervenes with inflammatory PGE2 and LT biosynthesis. Comprehensive lipid mediator (LM) metabololipidomics with activated human monocyte-derived macrophages showed that TG554 selectively inhibits inflammatory PGE2 formation over all cyclooxygenase (COX)-derived prostanoids, does not cause substrate shunting towards 5-lipoxygenase (5-LOX) pathway, and does not interfere with the biosynthesis of the specialized pro-resolving mediators as observed with COX inhibitors, providing a new chemotype for effective and safer anti-inflammatory drug development.

Synthesis and evaluation of indomethacin prodrugs with a diester structure that are metabolically activated by human carboxylesterases.

1. Carboxylesterase (CES) has been studied extensively, mostly with substrates in the monoester structures. We investigated the relationship between indomethacin diester prodrugs and metabolic activation by microsomes and recombinant human CES.2. Eight indomethacin diester prodrugs were synthesised in two steps. They were used as substrates and hydrolysis rates were calculated.3. As a result, the major hydrolysis enzyme was CES. The hydrolysis rate of recombinant CES2A1 was comparable to that of recombinant CES1A1.4. In this study, by changing the structure of the prodrug to a diester structure, it was found that CES2 activity was equivalent to CES1 activity.5. It should be noted that the use of diester prodrugs in prodrug discovery, where organ-specific hydrolysis reactions are expected, may not yield the expected results.

Computational exploration of microsomal cytochrome P450 3A1 enzyme modulation by phytochemicals of Cichorium intybus L.: Insights into drug metabolism.

Drug metabolism plays a crucial role in drug fate, including therapeutic inactivation or activation, as well as the formation of toxic compounds. This underscores the importance of understanding drug metabolism in drug discovery and development. Considering the substantial costs associated with traditional drug development methods, computational approaches have emerged as valuable tools for predicting the metabolic fate of drug candidates. With this in mind, the present study aimed to investigate the potential mechanisms underlying the modulation of microsomal cytochrome P450 3A1 (CYP3A1) enzyme activity by various phytochemicals found in Cichorium intybus L., commonly known as chicory. To achieve this goal, several in silico methods, including molecular docking and molecular dynamics (MD) simulation, were employed to explore computationally the microsomal CYP3A1 enzyme. Schrodinger software was utilized for the molecular docking study, which involved the interaction analysis between CYP3A1 and 28 phytoconstituents of Cichorium intybus. Virtual screening of 28 compounds from chicory led to the identification of the top five ranked compounds. These compounds were evaluated for drug-likeness properties, pharmacokinetic profiles, and predicted binding affinities to CYP3A1. Caffeoylshikimic acid and cichoric acid emerged as promising candidates due to their favorable characteristics, including good oral bioavailability and high binding affinities to CYP3A1. Molecular dynamics simulations were conducted to assess the stability of caffeoylshikimic acid within the CYP3A1 binding pocket. The results demonstrated that caffeoylshikimic acid maintained stable interactions with the enzyme throughout the simulation, suggesting its potential as an effective modulator of CYP3A1 activity. The findings of this study have the potential to provide valuable insights into the complex molecular mechanisms by which Cichorium intybus L. acts on hepatocytes and modulates CYP3A1 enzyme expression or activity. By elucidating the impact of these phytochemicals on drug metabolism, this research contributes to our understanding of how chicory may interact with drugs and influence their efficacy and safety profiles.

Hydroxylated Tetramethoxyflavone Affects Intestinal Cell Permeability and Inhibits Cytochrome P450 Enzymes.

Tetramethoxyflavones (TMFs) found in the Citrus genus have garnered considerable interest from food scientists and the health food industry because of their promising biological properties. Nonetheless, there are currently limited data available regarding the effectiveness and bioavailability of "hydroxylated TMFs", which are flavones known for their potential in disease prevention through dietary means. This study aims to provide insights into the chemical and biological properties of hydroxylated TMF and evaluates its effects on intestinal cell permeability and cytochrome P450 (CYP) inhibition. Liquid chromatography-mass spectrometry (LC-MS) and microsomes analyze the TMFs and hydroxylated TMFs, elucidating cell penetration and metabolic inhibition potential. 3H7-TMF shows the fastest (1-h) transport efficiency in intestinal cells. The Caco-2 cell model exhibits significant transport and absorption efficiency. Dissolved hydroxyl-TMF with hydrophilicity possibly permeates the gut. 3H7-TMF has higher transport efficiency (46%) 3H6-TMF (39%). IC50 values of TMFs (78-TMF, 57-TMF, 3H7-TMF, 3H6-TMF) against CYP enzymes (CYP1A2, CYP2D6, CYP2C9, CYP2C19, CYP3A4) range from 0.15 to 108 µM, indicating potent inhibition. Hydroxyl groups enhance TMF hydrophilicity and membrane permeability. TMFs display varied inhibitory effects due to hydroxyl and methoxy hindrance. This study underscores the strong CYP inhibitory capabilities in these TMFs, implying potential food-drug interactions if used in medicines or supplements. These findings can also help with food nutrition improvement and pharma food developments through innovative approaches for Citrus waste valorization.

Dehydrogenase reductase 9 (SDR9C4) and related homologs recognize a broad spectrum of lipid mediator oxylipins as substrates.

Bioactive oxylipins play multiple roles during inflammation and in the immune response, with termination of their actions partly dependent on the activity of yet-to-be characterized dehydrogenases. Here, we report that human microsomal dehydrogenase reductase 9 (DHRS9, also known as SDR9C4 of the short-chain dehydrogenase/reductase (SDR) superfamily) exhibits a robust oxidative activity toward oxylipins with hydroxyl groups located at carbons C9 and C13 of octadecanoids, C12 and C15 carbons of eicosanoids, and C14 carbon of docosanoids. DHRS9/SDR9C4 is also active toward lipid inflammatory mediator dihydroxylated Leukotriene B4 and proresolving mediators such as tri-hydroxylated Resolvin D1 and Lipoxin A4, although notably, with lack of activity on the 15-hydroxyl of prostaglandins. We also found that the SDR enzymes phylogenetically related to DHRS9, i.e., human SDR9C8 (or retinol dehydrogenase 16), the rat SDR9C family member known as retinol dehydrogenase 7, and the mouse ortholog of human DHRS9 display similar activity toward oxylipin substrates. Mice deficient in DHRS9 protein are viable, fertile, and display no apparent phenotype under normal conditions. However, the oxidative activity of microsomal membranes from the skin, lung, and trachea of Dhrs9-/- mice toward 1 µM Leukotriene B4 is 1.7- to 6-fold lower than that of microsomes from wild-type littermates. In addition, the oxidative activity toward 1 µM Resolvin D1 is reduced by about 2.5-fold with DHRS9-null microsomes from the skin and trachea. These results strongly suggest that DHRS9 might play an important role in the metabolism of a wide range of bioactive oxylipins in vivo.

Adding to the STING.

STING (also known as MITA) is a central component in innate immunity against DNA virus. In this issue of Immunity, Wang et al. (2014) demonstrate that K27-linked polyubiquitination of STING (MITA) by the ER-associated E3 ligase AMFR is essential for STING (MITA)-mediated signaling and innate antiviral response.

The E3 ubiquitin ligase AMFR and INSIG1 bridge the activation of TBK1 kinase by modifying the adaptor STING.

Stimulator of interferon genes (STING, also known as MITA, ERIS, or MPYS) is essential for host immune responses triggered by microbial DNAs. However, the regulatory mechanisms underlying STING-mediated signaling are not fully understood. We report here that, upon cytoplasmic DNA stimulation, the endoplasmic reticulum (ER) protein AMFR was recruited to and interacted with STING in an insulin-induced gene 1 (INSIG1)-dependent manner. AMFR and INSIG1, an E3 ubiquitin ligase complex, then catalyzed the K27-linked polyubiquitination of STING. This modification served as an anchoring platform for recruiting TANK-binding kinase 1 (TBK1) and facilitating its translocation to the perinuclear microsomes. Depletion of AMFR or INSIG1 impaired STING-mediated antiviral gene induction. Consistently, myeloid-cell-specific Insig1(-/-) mice were more susceptible to herpes simplex virus 1 (HSV-1) infection than wild-type mice. This study uncovers an essential role of the ER proteins AMFR and INSIG1 in innate immunity, revealing an important missing link in the STING signaling pathway.

Sex- and enantiospecific differences in the formation rate of hydroxyeicosatetraenoic acids in rat organs.

Hydroxyeicosatetraenoic acids (HETEs) are hydroxylated arachidonic acid (AA) metabolites that are classified into midchain, subterminal, and terminal HETEs. Hydroxylation results in the formation of R and S enantiomers for each HETE, except for 20-HETE. HETEs have multiple physiological and pathological effects. Several studies have demonstrated sex-specific differences in AA metabolism in different organs. In this study, microsomes from the heart, liver, kidney, lung, intestine, and brain of adult male and female Sprague-Dawley rats were isolated and incubated with AA. Thereafter, the enantiomers of all HETEs were analyzed by liquid chromatography-tandem mass spectrometry. We found significant sex- and enantiospecific differences in the formation levels of different HETEs in all organs. The majority of HETEs, especially midchain HETEs and 20-HETE, showed significantly higher formation rates in male organs. In the liver, the R enantiomer of several HETEs showed a higher formation rate than the corresponding S enantiomer (e.g., 8-, 9-, and 16-HETE). On the other hand, the brain and small intestine demonstrated a higher abundance of the S enantiomer. 19(S)-HETE was more abundant than 19(R)-HETE in all organs except the kidney. Elucidating sex-specific differences in HETE levels provides interesting insights into their physiological and pathophysiological roles and their possible implications for different diseases.

Resveratrol protects against cadmium-induced cerebrum toxicity through modifications of the cytochrome P450 enzyme system in microsomes.

BACKGROUND: Cadmium (Cd), known as a vital contaminant in the environment, penetrates the blood-brain barrier and accumulates in the cerebrum. Acute toxicosis of Cd, which leads to lethal cerebral edema, intracellular accumulation and cellular dysfunction, remains to be illuminated with regard to the exact molecular mechanism of cerebral toxicity. Resveratrol (RES), present in the edible portions of numerous plants, is a simply acquirable and correspondingly less toxic natural compound with neuroprotective potential, which provides some theoretical bases for antagonizing Cd-induced cerebral toxicity. RESULTS: This work was executed to research the protective effects of RES against Cd-induced toxicity in chicken cerebrum. Markedly, these lesions were increased in the Cd group, which also exhibited a thinner cortex, reduced granule cells, vacuolar degeneration, and an enlarged medullary space in the cerebrum. Furthermore, Cd induced CYP450 enzyme metabolism disorders by disrupting the nuclear xenobiotic receptor response (NXRs), enabling the cerebrum to reduce the ability to metabolize exogenous substances, eventually leading to Cd accumulation. Meanwhile, accumulated Cd promoted oxidative damage and synergistically promoted the damage to neurons and glial cells. CONCLUSION: RES initiated NXRs (especially for aromatic receptor and pregnancy alkane X receptor), decreasing the expression of CYP450 genes, changing the content of CYP450, maintaining CYP450 enzyme normal activities, and exerting antagonistic action against the Cd-induced abnormal response of nuclear receptors. These results suggest that the cerebrum toxicity caused by Cd was reduced by pretreatment with RES. © 2023 Society of Chemical Industry.

Identification and functional validation of novel pharmacogenomic variants using a next-generation sequencing-based approach for clinical pharmacogenomics.

Inter-individual variability in pharmacokinetics and drug response is heavily influenced by single-nucleotide variants (SNVs) and copy-number variations (CNVs) in genes with importance for drug disposition. Nowadays, a plethora of studies implement next generation sequencing to capture rare and novel pharmacogenomic (PGx) variants that influence drug response. To address these issues, we present a comprehensive end-to-end analysis workflow, beginning from targeted PGx panel re-sequencing to in silico analysis pipelines and in vitro validation assays. Specifically, we show that novel pharmacogenetic missense variants that are predicted or putatively predicted to be functionally deleterious, significantly alter protein activity levels of CYP2D6 and CYP2C19 proteins. We further demonstrate that variant priorization pipelines tailored with functional in vitro validation assays provide supporting evidence for the deleterious effect of novel PGx variants. The proposed workflow could provide the basis for integrating next-generation sequencing for PGx testing into routine clinical practice.