The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especi...The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especially in metabolic behavior. As a result, it is of vital importance to separate the enantiomers of a chiral drug in metabolic studies. This paper discusses enantioselective methods (include high-performance liquid chromatography, gas chromatography, capillary electrophoresis and high-performance liquid chromatography-mass spectrometry) that applied in chiral drug metabolism, using most recent examples where possible.展开更多
Patients with epidermal growth factor receptor(EGFR)wild-type non-small cell lung cancer(NSCLC)often show primary resistance to gefitinib therapy.It is thus necessary to study the metabolism of gefitinib in NSCLC cell...Patients with epidermal growth factor receptor(EGFR)wild-type non-small cell lung cancer(NSCLC)often show primary resistance to gefitinib therapy.It is thus necessary to study the metabolism of gefitinib in NSCLC cells to comprehensively reveal the reasons for the primary resistance of tumors.Herein,we develop a platform for studying drug metabolism heterogeneity based on single-cell mass spectrometry(sDMH-scMS)by integrating living-cell electrolaunching ionization MS(ILCEI-MS)and high-performance liquid chromatography-MS(HPLC-MS)analysis,and the primary resistance of NSCLC cells to gefitinib was studied using this platform.The ILCEI-MS analysis showed that approximately 11.9%of NSCLC single cells contained the gefitinib metabolite M11;HPLC-MS detection diluted the intensity of M11 in subpopulations and concealed the heterogeneity of drug metabolism in tumor single cells.The intensity of gefitinib in EGFR wild-type A549 cells was markedly lower than in mutant PC9 cells,and the intensity of gefitinib metabolites was significantly higher than in PC9 cells,suggesting that the primary resistance of NSCLC cells is related to gefitinib metabolism.Moreover,the combination of gefitinib and the drug-metabolizing enzyme inhibitorα-naphthoflavone was shown to overcome the primary resistance of the NSCLC cells.Overall,the results of this study are expected to be applicable for clinical drug resistance diagnosis and treatment at the single-cell level.展开更多
The drug metabolism is a biochemical process on modification of pharmaceutical substances through specialized enzymatic systems. Changes in the expression of drug-metabolizing enzyme genes can affect drug metabolism. ...The drug metabolism is a biochemical process on modification of pharmaceutical substances through specialized enzymatic systems. Changes in the expression of drug-metabolizing enzyme genes can affect drug metabolism. Recently, epigenetic regulation of drug-metabolizing enzyme genes has emerged as an important mechanism. Epigenetic regulation refers to heritable factors of genomic modifications that do not involve changes in DNA sequence. Examples of such modifications include DNA methylation, histone modifications, and non-coding RNAs. This review examines the widespread effect of epigenetic regulations on genes involved in drug metabolism, and also suggests a network perspective of epigenetic regulation. The epigenetic mechanisms have important clinical implications and may provide insights into effective drug development and improve safety of drug therapy.展开更多
The 2020 Nobel Prize in Chemistry recognized CRISPR-Cas9,a super-selective and precise gene editing tool.CRISPR-Cas9 has an obvious advantage in editing multiple genes in the same cell,and presents great potential in ...The 2020 Nobel Prize in Chemistry recognized CRISPR-Cas9,a super-selective and precise gene editing tool.CRISPR-Cas9 has an obvious advantage in editing multiple genes in the same cell,and presents great potential in disease treatment and animal model construction.In recent years,CRISPRCas9 has been used to establish a series of rat models of drug metabolism and pharmacokinetics(DMPK),such as Cyp,Abcb1,Oatp1 b2 gene knockout rats.These new rat models are not only widely used in the study of drug metabolism,chemical toxicity,and carcinogenicity,but also promote the study of DMPK related mechanism,and further strengthen the relationship between drug metabolism and pharmacology/toxicology.This review systematically introduces the advantages and disadvantages of CRISPR-Cas9,summarizes the methods of establishing DMPK rat models,discusses the main challenges in this field,and proposes strategies to overcome these problems.展开更多
Variations in drug metabolism may alter drug efficacy and cause toxicity;better understanding of the mechanisms and risks shall help to practice precision medicine.At the 21 st International Symposium on Microsomes an...Variations in drug metabolism may alter drug efficacy and cause toxicity;better understanding of the mechanisms and risks shall help to practice precision medicine.At the 21 st International Symposium on Microsomes and Drug Oxidations held in Davis,California,USA,in October 2-6,2016,a number of speakers reported some new findings and ongoing studies on the regulation mechanisms behind variable drug metabolism and toxicity,and discussed potential implications to personalized medications.A considerably insightful overview was provided on genetic and epigenetic regulation of gene expression involved in drug absorption,distribution,metabolism,and excretion(ADME) and drug response.Altered drug metabolism and disposition as well as molecular mechanisms among diseased and special populations were presented.In addition,the roles of gut microbiota in drug metabolism and toxicology as well as long non-coding RNAs in liver functions and diseases were discussed.These findings may offer new insights into improved understanding of ADME regulatory mechanisms and advance drug metabolism research.展开更多
Drug discovery and development involve the utilization of in vitro and in vivo ex perimental models.Different models,ranging from test tube experiments to cell cultures,animals,healthy human subjects,and even small nu...Drug discovery and development involve the utilization of in vitro and in vivo ex perimental models.Different models,ranging from test tube experiments to cell cultures,animals,healthy human subjects,and even small numbers of patients that are involved in clinical trials,are used at different stages of drug discovery and development for determination of efficacy and safety.The proper selection and applications of correct models,as well as appropriate data interpretation,are critically important in decision making and succesful advancement of drug candidates.In this review,we discuss strategies in the applications of both in vitro and in vivo.experimental models of drug metabolism and disposition.展开更多
Cytochrome P450(CYP)enzymes function to catalyze a wide range of reactions,many of which are critically important for drug response.Members of the human cytochrome P4503A(CYP3A)family are particularly important in dru...Cytochrome P450(CYP)enzymes function to catalyze a wide range of reactions,many of which are critically important for drug response.Members of the human cytochrome P4503A(CYP3A)family are particularly important in drug clearance,and they collectively metabolize more than half of all currently prescribed medications.The ability of these enzymes to bind a large and structurally diverse set of compounds increases the chances of their modulating or facilitating drug metabolism in unfavorable ways.Emerging evidence suggests that individual enzymes in the CYP3A family play discrete and important roles in catalysis and disease progression.Here we review the similarities and differences among CYP3A enzymes with regard to substrate recognition,metabolism,modulation by small molecules,and biological consequence,highlighting some of those with clinical significance.We also present structural perspectives to further characterize the basis of these comparisons.展开更多
Three-dimensional(3D)cell spheroid models combined with mass spectrometry imaging(MSI)enables innovative investigation of in vivo-like biological processes under different physiological and pathological conditions.Her...Three-dimensional(3D)cell spheroid models combined with mass spectrometry imaging(MSI)enables innovative investigation of in vivo-like biological processes under different physiological and pathological conditions.Herein,airflow-assisted desorption electrospray ionization-MSI(AFADESI-MSI)was coupled with 3D HepG2 spheroids to assess the metabolism and hepatotoxicity of amiodarone(AMI).High-coverage imaging of>1100 endogenous metabolites in hepatocyte spheroids was achieved using AFADESI-MSI.Following AMI treatment at different times,15 metabolites of AMI involved in Ndesethylation,hydroxylation,deiodination,and desaturation metabolic reactions were identified,and according to their spatiotemporal dynamics features,the metabolic pathways of AMI were proposed.Subsequently,the temporal and spatial changes in metabolic disturbance within spheroids caused by drug exposure were obtained via metabolomic analysis.The main dysregulated metabolic pathways included arachidonic acid and glycerophospholipid metabolism,providing considerable evidence for the mechanism of AMI hepatotoxicity.In addition,a biomarker group of eight fatty acids was selected that provided improved indication of cell viability and could characterize the hepatotoxicity of AMI.The combination of AFADESI-MSI and HepG2 spheroids can simultaneously obtain spatiotemporal information for drugs,drug metabolites,and endogenous metabolites after AMI treatment,providing an effective tool for in vitro drug hepatotoxicity evaluation.展开更多
Since metabolism significantly affects drug safety and efficacy,determining the metabolic profile of a drug is a critical part of drug development.The application of an LC–MS-based metabolomic approach has gained mor...Since metabolism significantly affects drug safety and efficacy,determining the metabolic profile of a drug is a critical part of drug development.The application of an LC–MS-based metabolomic approach has gained more widespread use in identifying drug metabolites,developing metabolic maps and lending clues to mechanisms of bioactivation.Thus,the LC–MS-based metabolomic approach is a powerful tool for profiling of drug metabolism and bioactivation.展开更多
In pre-clinical phase of new drug development,it is particularly important to establish an in vitro model to mimic the metabolism situation of human body.The aim of the in vitro model is to reduce the usage of experim...In pre-clinical phase of new drug development,it is particularly important to establish an in vitro model to mimic the metabolism situation of human body.The aim of the in vitro model is to reduce the usage of experimental animals and to make a more accurate prediction of the drug metabolism in vivo.Microfluidic chip is an emerging technology to establish predictive models.By integrating subcellular fractions,hepatocytes or liver tissue in the microfluidic chips,more predictive in vitro metabolism models can be established for drug development.The microfluidic platform offers dynamic and controlled fluids,as well as sophisticated liver tissue assembly to remodel the physiological and pathological microenvironment of liver in the human body.This review updates the microfluidic-based liver drug metabolism models since 2011,and summarizes the development of different models based on different chip vectors(subcellular components,primary hepatocytes,and tissue sections).It serves as a guide for newcomers to this dynamic field.展开更多
A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and...A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and to determine CO formed during the microsomal metabolism of xenobiotics in vitro. The method can significantly eliminate the background interference in the assay media and increase the quantitative accuracy and the sensitivity. There is a good linear relationship between CO concentration in the range of 2~10 μmol·L 1 CO and the distance D between the first derivative peak at 415 nm amd valley at 426 nm with r=0.9999(n=5),the regression equation being C (mmol·L 1 )=17.6D 0.4, the detection limit lower than 0.1 μmol·L 1 CO. The average recoveries of CO from the assay system and the sample were 102.1%, RSD=2.9% (n=7) and 79.7%, RSD=6.8% (n=12),respectively. The RSD of within day was 4.4%(n=18),and the RSD of day to day was 6.1%(n=16). By this method, four trihaloanilines and one trihalobenzene were tested, the results showed that only 2,4,5 trifluoroaniline could be converted to CO by the incubation with rat hepatic microsomes, NADPH and oxygen, the ability of phenobarbital or dexamethasone to induce rat hepatic microsomes to catalyze CO formation was 3 or 8 times higher than that of the control.展开更多
The classic view on the pathogenesis of drug-induced liver injury is that the so-called parent compounds are made hepatotoxic by metabolism (formation of neosubstances that react abnormally), mainly by cytochromes P-4...The classic view on the pathogenesis of drug-induced liver injury is that the so-called parent compounds are made hepatotoxic by metabolism (formation of neosubstances that react abnormally), mainly by cytochromes P-450 (CYP), with further pathways, such as mitochondrial dysfunction and apoptosis, also playing a role. Risk factors for drug-induced liver injury include concomitant hepatic diseases, age and genetic polymorphisms of CYP. However, some susceptibility can today be predicted before drug administration, working on the common substrate, by phenotyping and genotyping studies and by taking in consideration patients' health status. Physicians should always think of this adverse effect in the absence of other clear hepatic disease. Ethical and legal problems towards operators in the health care system are always matters to consider.展开更多
AIM To ascertain whether cholestasis affects the expression of two CYP3 A isoforms(CYP3 A1 and CYP3 A2) and of pregnane X receptor(PXR) and constitutive androstane receptor(CAR).METHODS Cholestasis was induced by bile...AIM To ascertain whether cholestasis affects the expression of two CYP3 A isoforms(CYP3 A1 and CYP3 A2) and of pregnane X receptor(PXR) and constitutive androstane receptor(CAR).METHODS Cholestasis was induced by bile duct ligation in 16 male Wistar rats; whereas 8 sham-operated rats were used as controls. Severity of cholestasis was assessed on histological examination of liver sections, and serum concentrations of albumin, AST, ALT, GGT, ALPK and bilirubin. Gene and protein expressions of PXR, CAR, CYP3 A1 and CYP3 A2 were assessed by means of q RT-PCR and Western blot, respectively. Alterations in CYP3 A activity were measured by calculating the kinetic parameters of 4-OH and 1'-OH-midazolam hydroxylation, marker reactions for CYP3 A enzymes.RESULTS The m RNA and protein expression of CYP3 A1 increased significantly in mild cholestasis(P < 0.01). At variance, m RNA and protein expression of CYP3 A2 didn't change in mild cholestasis, whereas the expression and activity of both CYP3 A1 and CYP3 A2 decreased dramatically when cholestasis became severe. Consistently with these observations, the nuclear expression of both PXR and CAR, which was measured because they both translocate into the cell nucleus after their activation, virtually disappeared in the late stage of cholestatic injury, after an initial increase. These results indicate that early-and late-stage cholestasis affects CYP3 Amediated drug metabolism differently, probably as consequence of the different activation of PXR and CAR.CONCLUSION Early-and late-stage cholestasis affects CYP3 Amediated drug metabolism differently. PXR and CAR might be targeted therapeutically to promote CYP3 Amediated liver detoxification.展开更多
BACKGROUND: Enzymes involved in drug and xenobiotic metabolism have been considered to exist in two groups: phase I and phase II enzymes. Cytochrome P450 isoenzymes (CYPs) are the most important phase I enzymes in the...BACKGROUND: Enzymes involved in drug and xenobiotic metabolism have been considered to exist in two groups: phase I and phase II enzymes. Cytochrome P450 isoenzymes (CYPs) are the most important phase I enzymes in the metabolism of xenobiotics. The products of phase I metabolism are then acted upon by phase II enzymes, including glutathione S-transferases (GSTs). Herbs that inhibit CYPs such as CYP3A4 or that induce GSTs may have the potential to protect against chemical carcinogenesis since the mutagenic effects of carcinogens are often mediated through an excess of CYP-generated reactive intermediates. This study was designed to investigate the effects of salvianolic acid B (Sal B), a pure compound extracted from Radix Salviae Miltiorrhizae, a Chinese herb, on cell proliferation and CYP1A2 and CYP3A4 mRNA expression in the presence or absence of rifampicin, a potent inducer of CYPs and GST protein expression in HepG2 cells. METHODS: HepG2 cells were incubated with different concentrations of Sal B. Cell proliferation was determined by SYTOX-Green nucleic acid staining. CYP3A4 and CYP1A2 mRNA expression was assayed by real-time PCR. GST protein expression was analyzed by Western blotting. RESULTS: Low concentrations of Sal B (0-20 μmol/L) had no significant effects on cell proliferation, while higher concentrations (100-250 μmol/L) significantly inhibited proliferation in a concentration-dependent manner. Ten μmol/L Sal B, but not 1 μmol/L, down-regulated CYP3A4 and CYP1A2 mRNA expression after 24 hours of incubation, whereas both 1 and 10 μmol/L Sal B down-regulated CYP3A4mRNA expression after 96 hours of incubation; moreover, 1 and 10 μmol/L Sal B inhibited CYP3A4 mRNA expression induced by rifampicin. Both 1 μmol/L and 10 μmol/L Sal B increased GST expression. CONCLUSION: Sal B inhibits CYP3A4 and CYP1A2 mRNA expression and induces GST expression in HepG2 cells.展开更多
Exposure to some toxic compounds causes structural and behavioral anomalies associated with the neurons in the later stage of life.Those toxic compounds are termed as a neurotoxicant,which can be a physical factor,a t...Exposure to some toxic compounds causes structural and behavioral anomalies associated with the neurons in the later stage of life.Those toxic compounds are termed as a neurotoxicant,which can be a physical factor,a toxin,an infection,radiation,or maybe a drug.The incongruities caused due to a neurotoxicant further depend on the toxicity of the compound.More importantly,the neurotoxicity of the compound is associated with the concentration and the time point of exposure.The neurodevelopmental defect appears depending on the toxicity of the compound.A neurodevelopmental defect may be associated with a delay in developmental time,defective growth,structural abnormality of many organs,including sensory organs,behavioral abnormalities,or death in the fetus stage.Numerous model organisms are employed to assess the effect of neurotoxicants.The current review summarizes several methods used to check the effect of neurotoxicant and their effect using the model organism Drosophila melanogaster.展开更多
BACKGROUND The coronavirus disease 2019(COVID-19),a pandemic contributing to more than 105 million cases and more than 2.3 million deaths worldwide,was described to be frequently accompanied by extrapulmonary manifest...BACKGROUND The coronavirus disease 2019(COVID-19),a pandemic contributing to more than 105 million cases and more than 2.3 million deaths worldwide,was described to be frequently accompanied by extrapulmonary manifestations,including liver dysfunction.Liver dysfunction and elevated liver enzymes were observed in about 53%of COVID-19 patients.AIM To gain insight into transcriptional abnormalities in liver tissue of severe COVID-19 patients that may result in liver dysfunction.METHODS The transcriptome of liver autopsy samples from severe COVID-19 patients against those of non-COVID donors was analyzed.Differentially expressed genes were identified from normalized RNA-seq data and analyzed for the enrichment of functional clusters and pathways.The differentially expressed genes were then compared against the genetic signatures of liver diseases including cirrhosis,fibrosis,non-alcoholic fatty liver disease(NAFLD),and hepatitis A/B/C.Gene expression of some differentially expressed genes was assessed in the blood samples of severe COVID-19 patients with liver dysfunction using qRT-PCR.RESULTS Analysis of the differential transcriptome of the liver tissue of severe COVID-19 patients revealed a significant upregulation of transcripts implicated in tissue remodeling including G-coupled protein receptors family genes,DNAJB1,IGF2,EGFR,and HDGF.Concordantly,the differential transcriptome of severe COVID-19 liver tissues substantially overlapped with the disease signature of liver diseases characterized with pathological tissue remodeling(liver cirrhosis,Fibrosis,NAFLD,and hepatitis A/B/C).Moreover,we observed a significant suppression of transcripts implicated in metabolic pathways as well as mitochondrial function,including cytochrome P450 family members,ACAD11,CIDEB,GNMT,and GPAM.Consequently,drug and xenobiotics metabolism pathways are significantly suppressed suggesting a decrease in liver detoxification capacity.In correspondence with the RNA-seq data analysis,we observed a significant upregulation of DNAJB1 and HSP90AB1 as well as significant downregulation of CYP39A1 in the blood plasma of severe COVID-19 patients with liver dysfunction.CONCLUSION Severe COVID-19 patients appear to experience significant transcriptional shift that may ensue tissue remodeling,mitochondrial dysfunction and lower hepatic detoxification resulting in the clinically observed liver dysfunction.展开更多
We have previously introduced the use of permeabilized fission yeast cells(enzyme bags)that recombinantly express full-length CYPs for drug metabolism studies.Such enzyme bags are cells with pores that function as enz...We have previously introduced the use of permeabilized fission yeast cells(enzyme bags)that recombinantly express full-length CYPs for drug metabolism studies.Such enzyme bags are cells with pores that function as enzymes in situ.They can easily be prepared without a need for ultracentrifugation and may be used in similar protocols as microsomes.In this study we report the preparation of enzyme bag cocktails that permit the testing of multiple CYPs in a single enzyme bag reaction.Moreover,we established a convenient testing scheme that permits a rapid screen of all human CYPs for activity towards any given candidate substrate.An important aspect of this approach is the reduction of individual CYP test assays.If a cocktail containing many CYPs tests negative,it follows that all CYPs included in that cocktail need not be tested individually,thus saving time and resources.The new protocol was validated using two probe substrates.展开更多
The effect of cimetidine on the elimination of praziquantel(PQT)in rats was studied. The results showed that cimetidine 100 mg/kg,ip 2 reduced the clearances of intravenous and oral PQT by 60 and 69 percent respective...The effect of cimetidine on the elimination of praziquantel(PQT)in rats was studied. The results showed that cimetidine 100 mg/kg,ip 2 reduced the clearances of intravenous and oral PQT by 60 and 69 percent respectively.Cimetidine also markedly reduced liver blood flow of rats(a reduction of 58%)and inhibited PQT metabolism in hepatic microsomes of rats(an inhibition of 55%). The reduction in clearance of intravenous PQT could be attributed to the result of cimetidine lowering liver blood flow,whereas the reduction in clearance of oral PQT might be related mainly to the inhibition of cimetidine on the activity of hepatic drug-metabolizing enzymes.展开更多
Background: Voriconazole is frequently used to treat fungal infections in solid organ transplant patients. Recently, there have been reports suggesting that prolonged voriconazole therapy may lead to periostitis. Aim:...Background: Voriconazole is frequently used to treat fungal infections in solid organ transplant patients. Recently, there have been reports suggesting that prolonged voriconazole therapy may lead to periostitis. Aim: Here we present two cases of voriconazole-induced periostitis in solid organ transplant patients. Case Presentation: Voriconazole was given to two transplant patients-one with a liver transplant and the second with a heart transplant, to treat their fungal infections. Both developed voriconazole-induced toxicity. While undergoing voriconazole therapy, they had incapacitating bone pain. The liver transplant patient had to be taken off voriconazole, and the heart transplant patient succumbed to non-voriconazole related causes. Conclusions: Voriconazole therapy in two solid organ transplant patients resulted in periostitis. We provide potential etiologies underlying voriconazole-induced periostitis, including fluoride toxicity, abnormalities in the pulmonary vascular bed leading to the production of downstream inflammatory mediators, and abnormal pharmacokinetics of hepatic drug metabolism. In addition to monitoring blood voriconazole trough levels, we suggest careful assessment for musculoskeletal pain in patients undergoing voriconazole treatment for two months or more, particularly if their daily dosages of voriconazole exceed 500 mg per day. Appropriate workup should include measurement of alkaline phosphatase and fluoride levels, voriconazole trough and bone scan. Overall, early recognition of voriconazole-induced musculoskeletal toxicity is important for better morbidity outcomes.展开更多
基金National Natural Science Foundation of China(Grant No.30225047 and 30701038)
文摘The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especially in metabolic behavior. As a result, it is of vital importance to separate the enantiomers of a chiral drug in metabolic studies. This paper discusses enantioselective methods (include high-performance liquid chromatography, gas chromatography, capillary electrophoresis and high-performance liquid chromatography-mass spectrometry) that applied in chiral drug metabolism, using most recent examples where possible.
基金supported by the Beijing Outstanding Young Scientist Program(No.BJJWZYJH01201910005017)the National Natural Science Foundation of China(Nos.22127805 and 22206008).
文摘Patients with epidermal growth factor receptor(EGFR)wild-type non-small cell lung cancer(NSCLC)often show primary resistance to gefitinib therapy.It is thus necessary to study the metabolism of gefitinib in NSCLC cells to comprehensively reveal the reasons for the primary resistance of tumors.Herein,we develop a platform for studying drug metabolism heterogeneity based on single-cell mass spectrometry(sDMH-scMS)by integrating living-cell electrolaunching ionization MS(ILCEI-MS)and high-performance liquid chromatography-MS(HPLC-MS)analysis,and the primary resistance of NSCLC cells to gefitinib was studied using this platform.The ILCEI-MS analysis showed that approximately 11.9%of NSCLC single cells contained the gefitinib metabolite M11;HPLC-MS detection diluted the intensity of M11 in subpopulations and concealed the heterogeneity of drug metabolism in tumor single cells.The intensity of gefitinib in EGFR wild-type A549 cells was markedly lower than in mutant PC9 cells,and the intensity of gefitinib metabolites was significantly higher than in PC9 cells,suggesting that the primary resistance of NSCLC cells is related to gefitinib metabolism.Moreover,the combination of gefitinib and the drug-metabolizing enzyme inhibitorα-naphthoflavone was shown to overcome the primary resistance of the NSCLC cells.Overall,the results of this study are expected to be applicable for clinical drug resistance diagnosis and treatment at the single-cell level.
基金supported by the National Institute of Health,National Institute of General Medical Sciences (No.R01GM087376)National Institute of Health,National Institute for Environmental Health Sciences (No.R01ES-019487)
文摘The drug metabolism is a biochemical process on modification of pharmaceutical substances through specialized enzymatic systems. Changes in the expression of drug-metabolizing enzyme genes can affect drug metabolism. Recently, epigenetic regulation of drug-metabolizing enzyme genes has emerged as an important mechanism. Epigenetic regulation refers to heritable factors of genomic modifications that do not involve changes in DNA sequence. Examples of such modifications include DNA methylation, histone modifications, and non-coding RNAs. This review examines the widespread effect of epigenetic regulations on genes involved in drug metabolism, and also suggests a network perspective of epigenetic regulation. The epigenetic mechanisms have important clinical implications and may provide insights into effective drug development and improve safety of drug therapy.
基金supported in part by grants from the National Natural Science Foundation of China(No.81773808)the Science and Technology Commission of Shanghai Municipality(Nos.17140901000,17140901001 and 18430760400,China)。
文摘The 2020 Nobel Prize in Chemistry recognized CRISPR-Cas9,a super-selective and precise gene editing tool.CRISPR-Cas9 has an obvious advantage in editing multiple genes in the same cell,and presents great potential in disease treatment and animal model construction.In recent years,CRISPRCas9 has been used to establish a series of rat models of drug metabolism and pharmacokinetics(DMPK),such as Cyp,Abcb1,Oatp1 b2 gene knockout rats.These new rat models are not only widely used in the study of drug metabolism,chemical toxicity,and carcinogenicity,but also promote the study of DMPK related mechanism,and further strengthen the relationship between drug metabolism and pharmacology/toxicology.This review systematically introduces the advantages and disadvantages of CRISPR-Cas9,summarizes the methods of establishing DMPK rat models,discusses the main challenges in this field,and proposes strategies to overcome these problems.
基金supported by grants of U01CA175315 and R01GM113888 from the U.S.National Institutes of Health(NIH)supported by grants of ES006694 and ES007091 from NIH+8 种基金supported by grants of ES021800,ES020522,and ES005022 from NIHsupported by the Robert Bosch Foundation,Stuttgart,Germanysupported by grants of ES023438 and DK083952 from NIHsupported by grant of R01HL122593 from NIH and the Searle Scholars Program,USAsupported by grant of R01ES025708 from NIHsupported by grants of CA098468 and T32DK007737 from NIHsupported by grants of R01DK33765 and R01ES024421 from NIHsupported by grants of R01DK104656,R01DK080440,R01ES025909,R21AA022482,and R21AA024935 from NIH,grant of 1I01BX002634 from VA Merit Award,USA,grant of No.81572443 from National Natural Science Foundation of China,and grant of P30 DK34989 from Yale Liver Center,USAsupported by grants of R01ES019487,R01GM087367,and R01GM118367 from NIH
文摘Variations in drug metabolism may alter drug efficacy and cause toxicity;better understanding of the mechanisms and risks shall help to practice precision medicine.At the 21 st International Symposium on Microsomes and Drug Oxidations held in Davis,California,USA,in October 2-6,2016,a number of speakers reported some new findings and ongoing studies on the regulation mechanisms behind variable drug metabolism and toxicity,and discussed potential implications to personalized medications.A considerably insightful overview was provided on genetic and epigenetic regulation of gene expression involved in drug absorption,distribution,metabolism,and excretion(ADME) and drug response.Altered drug metabolism and disposition as well as molecular mechanisms among diseased and special populations were presented.In addition,the roles of gut microbiota in drug metabolism and toxicology as well as long non-coding RNAs in liver functions and diseases were discussed.These findings may offer new insights into improved understanding of ADME regulatory mechanisms and advance drug metabolism research.
基金Xinxin Ding was supported in part by Public Health Service grants CA-092596 and ES007462 from the National Institutes of Health.
文摘Drug discovery and development involve the utilization of in vitro and in vivo ex perimental models.Different models,ranging from test tube experiments to cell cultures,animals,healthy human subjects,and even small numbers of patients that are involved in clinical trials,are used at different stages of drug discovery and development for determination of efficacy and safety.The proper selection and applications of correct models,as well as appropriate data interpretation,are critically important in decision making and succesful advancement of drug candidates.In this review,we discuss strategies in the applications of both in vitro and in vivo.experimental models of drug metabolism and disposition.
基金supported,in part,by ALSAC and by the National Institutes of Health grants R35-GM118041 and P30-CA21765.
文摘Cytochrome P450(CYP)enzymes function to catalyze a wide range of reactions,many of which are critically important for drug response.Members of the human cytochrome P4503A(CYP3A)family are particularly important in drug clearance,and they collectively metabolize more than half of all currently prescribed medications.The ability of these enzymes to bind a large and structurally diverse set of compounds increases the chances of their modulating or facilitating drug metabolism in unfavorable ways.Emerging evidence suggests that individual enzymes in the CYP3A family play discrete and important roles in catalysis and disease progression.Here we review the similarities and differences among CYP3A enzymes with regard to substrate recognition,metabolism,modulation by small molecules,and biological consequence,highlighting some of those with clinical significance.We also present structural perspectives to further characterize the basis of these comparisons.
基金funded by the National Natural Science Foundation of China(Grant No.:21874156)the Chinese Academy of Medical Science(CAMS)Innovation Fund for Medical Sciences(Grant No.:2021-1-I2M-028).
文摘Three-dimensional(3D)cell spheroid models combined with mass spectrometry imaging(MSI)enables innovative investigation of in vivo-like biological processes under different physiological and pathological conditions.Herein,airflow-assisted desorption electrospray ionization-MSI(AFADESI-MSI)was coupled with 3D HepG2 spheroids to assess the metabolism and hepatotoxicity of amiodarone(AMI).High-coverage imaging of>1100 endogenous metabolites in hepatocyte spheroids was achieved using AFADESI-MSI.Following AMI treatment at different times,15 metabolites of AMI involved in Ndesethylation,hydroxylation,deiodination,and desaturation metabolic reactions were identified,and according to their spatiotemporal dynamics features,the metabolic pathways of AMI were proposed.Subsequently,the temporal and spatial changes in metabolic disturbance within spheroids caused by drug exposure were obtained via metabolomic analysis.The main dysregulated metabolic pathways included arachidonic acid and glycerophospholipid metabolism,providing considerable evidence for the mechanism of AMI hepatotoxicity.In addition,a biomarker group of eight fatty acids was selected that provided improved indication of cell viability and could characterize the hepatotoxicity of AMI.The combination of AFADESI-MSI and HepG2 spheroids can simultaneously obtain spatiotemporal information for drugs,drug metabolites,and endogenous metabolites after AMI treatment,providing an effective tool for in vitro drug hepatotoxicity evaluation.
文摘Since metabolism significantly affects drug safety and efficacy,determining the metabolic profile of a drug is a critical part of drug development.The application of an LC–MS-based metabolomic approach has gained more widespread use in identifying drug metabolites,developing metabolic maps and lending clues to mechanisms of bioactivation.Thus,the LC–MS-based metabolomic approach is a powerful tool for profiling of drug metabolism and bioactivation.
基金National Natural Science Foundation of China(Grant No.81573684 and 81530097)Beijing Municipal Science and Technology Project(Grant No.Z181100002218028)National Key Technology R&D Program “New Drug Innovation” of China(Grant No.2018ZX09711001-008-003)
文摘In pre-clinical phase of new drug development,it is particularly important to establish an in vitro model to mimic the metabolism situation of human body.The aim of the in vitro model is to reduce the usage of experimental animals and to make a more accurate prediction of the drug metabolism in vivo.Microfluidic chip is an emerging technology to establish predictive models.By integrating subcellular fractions,hepatocytes or liver tissue in the microfluidic chips,more predictive in vitro metabolism models can be established for drug development.The microfluidic platform offers dynamic and controlled fluids,as well as sophisticated liver tissue assembly to remodel the physiological and pathological microenvironment of liver in the human body.This review updates the microfluidic-based liver drug metabolism models since 2011,and summarizes the development of different models based on different chip vectors(subcellular components,primary hepatocytes,and tissue sections).It serves as a guide for newcomers to this dynamic field.
文摘A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and to determine CO formed during the microsomal metabolism of xenobiotics in vitro. The method can significantly eliminate the background interference in the assay media and increase the quantitative accuracy and the sensitivity. There is a good linear relationship between CO concentration in the range of 2~10 μmol·L 1 CO and the distance D between the first derivative peak at 415 nm amd valley at 426 nm with r=0.9999(n=5),the regression equation being C (mmol·L 1 )=17.6D 0.4, the detection limit lower than 0.1 μmol·L 1 CO. The average recoveries of CO from the assay system and the sample were 102.1%, RSD=2.9% (n=7) and 79.7%, RSD=6.8% (n=12),respectively. The RSD of within day was 4.4%(n=18),and the RSD of day to day was 6.1%(n=16). By this method, four trihaloanilines and one trihalobenzene were tested, the results showed that only 2,4,5 trifluoroaniline could be converted to CO by the incubation with rat hepatic microsomes, NADPH and oxygen, the ability of phenobarbital or dexamethasone to induce rat hepatic microsomes to catalyze CO formation was 3 or 8 times higher than that of the control.
文摘The classic view on the pathogenesis of drug-induced liver injury is that the so-called parent compounds are made hepatotoxic by metabolism (formation of neosubstances that react abnormally), mainly by cytochromes P-450 (CYP), with further pathways, such as mitochondrial dysfunction and apoptosis, also playing a role. Risk factors for drug-induced liver injury include concomitant hepatic diseases, age and genetic polymorphisms of CYP. However, some susceptibility can today be predicted before drug administration, working on the common substrate, by phenotyping and genotyping studies and by taking in consideration patients' health status. Physicians should always think of this adverse effect in the absence of other clear hepatic disease. Ethical and legal problems towards operators in the health care system are always matters to consider.
基金Supported by the University of Padova,No.CPDA138721/13
文摘AIM To ascertain whether cholestasis affects the expression of two CYP3 A isoforms(CYP3 A1 and CYP3 A2) and of pregnane X receptor(PXR) and constitutive androstane receptor(CAR).METHODS Cholestasis was induced by bile duct ligation in 16 male Wistar rats; whereas 8 sham-operated rats were used as controls. Severity of cholestasis was assessed on histological examination of liver sections, and serum concentrations of albumin, AST, ALT, GGT, ALPK and bilirubin. Gene and protein expressions of PXR, CAR, CYP3 A1 and CYP3 A2 were assessed by means of q RT-PCR and Western blot, respectively. Alterations in CYP3 A activity were measured by calculating the kinetic parameters of 4-OH and 1'-OH-midazolam hydroxylation, marker reactions for CYP3 A enzymes.RESULTS The m RNA and protein expression of CYP3 A1 increased significantly in mild cholestasis(P < 0.01). At variance, m RNA and protein expression of CYP3 A2 didn't change in mild cholestasis, whereas the expression and activity of both CYP3 A1 and CYP3 A2 decreased dramatically when cholestasis became severe. Consistently with these observations, the nuclear expression of both PXR and CAR, which was measured because they both translocate into the cell nucleus after their activation, virtually disappeared in the late stage of cholestatic injury, after an initial increase. These results indicate that early-and late-stage cholestasis affects CYP3 Amediated drug metabolism differently, probably as consequence of the different activation of PXR and CAR.CONCLUSION Early-and late-stage cholestasis affects CYP3 Amediated drug metabolism differently. PXR and CAR might be targeted therapeutically to promote CYP3 Amediated liver detoxification.
基金supported by grants from the National Natural Science Foundation of China (30901943)the Program for New Century Excellent Talents in University (NCET-04-0437)+1 种基金the E-institute of Shanghai Municipal Education Commission (E03008)the Innovative Research Team in Universities of Shanghai Municipal Education Commission
文摘BACKGROUND: Enzymes involved in drug and xenobiotic metabolism have been considered to exist in two groups: phase I and phase II enzymes. Cytochrome P450 isoenzymes (CYPs) are the most important phase I enzymes in the metabolism of xenobiotics. The products of phase I metabolism are then acted upon by phase II enzymes, including glutathione S-transferases (GSTs). Herbs that inhibit CYPs such as CYP3A4 or that induce GSTs may have the potential to protect against chemical carcinogenesis since the mutagenic effects of carcinogens are often mediated through an excess of CYP-generated reactive intermediates. This study was designed to investigate the effects of salvianolic acid B (Sal B), a pure compound extracted from Radix Salviae Miltiorrhizae, a Chinese herb, on cell proliferation and CYP1A2 and CYP3A4 mRNA expression in the presence or absence of rifampicin, a potent inducer of CYPs and GST protein expression in HepG2 cells. METHODS: HepG2 cells were incubated with different concentrations of Sal B. Cell proliferation was determined by SYTOX-Green nucleic acid staining. CYP3A4 and CYP1A2 mRNA expression was assayed by real-time PCR. GST protein expression was analyzed by Western blotting. RESULTS: Low concentrations of Sal B (0-20 μmol/L) had no significant effects on cell proliferation, while higher concentrations (100-250 μmol/L) significantly inhibited proliferation in a concentration-dependent manner. Ten μmol/L Sal B, but not 1 μmol/L, down-regulated CYP3A4 and CYP1A2 mRNA expression after 24 hours of incubation, whereas both 1 and 10 μmol/L Sal B down-regulated CYP3A4mRNA expression after 96 hours of incubation; moreover, 1 and 10 μmol/L Sal B inhibited CYP3A4 mRNA expression induced by rifampicin. Both 1 μmol/L and 10 μmol/L Sal B increased GST expression. CONCLUSION: Sal B inhibits CYP3A4 and CYP1A2 mRNA expression and induces GST expression in HepG2 cells.
基金MM Lab is supported by SERB/EMR/2017/003054,BT/PR21857/NNT/28/1238/2017Odisha DBT 3325/ST(BIO)-02/2017.
文摘Exposure to some toxic compounds causes structural and behavioral anomalies associated with the neurons in the later stage of life.Those toxic compounds are termed as a neurotoxicant,which can be a physical factor,a toxin,an infection,radiation,or maybe a drug.The incongruities caused due to a neurotoxicant further depend on the toxicity of the compound.More importantly,the neurotoxicity of the compound is associated with the concentration and the time point of exposure.The neurodevelopmental defect appears depending on the toxicity of the compound.A neurodevelopmental defect may be associated with a delay in developmental time,defective growth,structural abnormality of many organs,including sensory organs,behavioral abnormalities,or death in the fetus stage.Numerous model organisms are employed to assess the effect of neurotoxicants.The current review summarizes several methods used to check the effect of neurotoxicant and their effect using the model organism Drosophila melanogaster.
基金The University of Sharjah,No.CoV19-0308,No.CoV19-0307 and No:1901090254Sharjah Research Academy,No:MED001Al-Jalila Foundation Seed Grant,No.AJF202019.
文摘BACKGROUND The coronavirus disease 2019(COVID-19),a pandemic contributing to more than 105 million cases and more than 2.3 million deaths worldwide,was described to be frequently accompanied by extrapulmonary manifestations,including liver dysfunction.Liver dysfunction and elevated liver enzymes were observed in about 53%of COVID-19 patients.AIM To gain insight into transcriptional abnormalities in liver tissue of severe COVID-19 patients that may result in liver dysfunction.METHODS The transcriptome of liver autopsy samples from severe COVID-19 patients against those of non-COVID donors was analyzed.Differentially expressed genes were identified from normalized RNA-seq data and analyzed for the enrichment of functional clusters and pathways.The differentially expressed genes were then compared against the genetic signatures of liver diseases including cirrhosis,fibrosis,non-alcoholic fatty liver disease(NAFLD),and hepatitis A/B/C.Gene expression of some differentially expressed genes was assessed in the blood samples of severe COVID-19 patients with liver dysfunction using qRT-PCR.RESULTS Analysis of the differential transcriptome of the liver tissue of severe COVID-19 patients revealed a significant upregulation of transcripts implicated in tissue remodeling including G-coupled protein receptors family genes,DNAJB1,IGF2,EGFR,and HDGF.Concordantly,the differential transcriptome of severe COVID-19 liver tissues substantially overlapped with the disease signature of liver diseases characterized with pathological tissue remodeling(liver cirrhosis,Fibrosis,NAFLD,and hepatitis A/B/C).Moreover,we observed a significant suppression of transcripts implicated in metabolic pathways as well as mitochondrial function,including cytochrome P450 family members,ACAD11,CIDEB,GNMT,and GPAM.Consequently,drug and xenobiotics metabolism pathways are significantly suppressed suggesting a decrease in liver detoxification capacity.In correspondence with the RNA-seq data analysis,we observed a significant upregulation of DNAJB1 and HSP90AB1 as well as significant downregulation of CYP39A1 in the blood plasma of severe COVID-19 patients with liver dysfunction.CONCLUSION Severe COVID-19 patients appear to experience significant transcriptional shift that may ensue tissue remodeling,mitochondrial dysfunction and lower hepatic detoxification resulting in the clinically observed liver dysfunction.
文摘We have previously introduced the use of permeabilized fission yeast cells(enzyme bags)that recombinantly express full-length CYPs for drug metabolism studies.Such enzyme bags are cells with pores that function as enzymes in situ.They can easily be prepared without a need for ultracentrifugation and may be used in similar protocols as microsomes.In this study we report the preparation of enzyme bag cocktails that permit the testing of multiple CYPs in a single enzyme bag reaction.Moreover,we established a convenient testing scheme that permits a rapid screen of all human CYPs for activity towards any given candidate substrate.An important aspect of this approach is the reduction of individual CYP test assays.If a cocktail containing many CYPs tests negative,it follows that all CYPs included in that cocktail need not be tested individually,thus saving time and resources.The new protocol was validated using two probe substrates.
文摘The effect of cimetidine on the elimination of praziquantel(PQT)in rats was studied. The results showed that cimetidine 100 mg/kg,ip 2 reduced the clearances of intravenous and oral PQT by 60 and 69 percent respectively.Cimetidine also markedly reduced liver blood flow of rats(a reduction of 58%)and inhibited PQT metabolism in hepatic microsomes of rats(an inhibition of 55%). The reduction in clearance of intravenous PQT could be attributed to the result of cimetidine lowering liver blood flow,whereas the reduction in clearance of oral PQT might be related mainly to the inhibition of cimetidine on the activity of hepatic drug-metabolizing enzymes.
文摘Background: Voriconazole is frequently used to treat fungal infections in solid organ transplant patients. Recently, there have been reports suggesting that prolonged voriconazole therapy may lead to periostitis. Aim: Here we present two cases of voriconazole-induced periostitis in solid organ transplant patients. Case Presentation: Voriconazole was given to two transplant patients-one with a liver transplant and the second with a heart transplant, to treat their fungal infections. Both developed voriconazole-induced toxicity. While undergoing voriconazole therapy, they had incapacitating bone pain. The liver transplant patient had to be taken off voriconazole, and the heart transplant patient succumbed to non-voriconazole related causes. Conclusions: Voriconazole therapy in two solid organ transplant patients resulted in periostitis. We provide potential etiologies underlying voriconazole-induced periostitis, including fluoride toxicity, abnormalities in the pulmonary vascular bed leading to the production of downstream inflammatory mediators, and abnormal pharmacokinetics of hepatic drug metabolism. In addition to monitoring blood voriconazole trough levels, we suggest careful assessment for musculoskeletal pain in patients undergoing voriconazole treatment for two months or more, particularly if their daily dosages of voriconazole exceed 500 mg per day. Appropriate workup should include measurement of alkaline phosphatase and fluoride levels, voriconazole trough and bone scan. Overall, early recognition of voriconazole-induced musculoskeletal toxicity is important for better morbidity outcomes.