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Cells Oct 2020During the last two decades, the constitutive androstane receptor (CAR; NR1I3) has emerged as a master activator of drug- and xenobiotic-metabolizing enzymes and... (Review)
Review
During the last two decades, the constitutive androstane receptor (CAR; NR1I3) has emerged as a master activator of drug- and xenobiotic-metabolizing enzymes and transporters that govern the clearance of both exogenous and endogenous small molecules. Recent studies indicate that CAR participates, together with other nuclear receptors (NRs) and transcription factors, in regulation of hepatic glucose and lipid metabolism, hepatocyte communication, proliferation and toxicity, and liver tumor development in rodents. Endocrine-disrupting chemicals (EDCs) constitute a wide range of persistent organic compounds that have been associated with aberrations of hormone-dependent physiological processes. Their adverse health effects include metabolic alterations such as diabetes, obesity, and fatty liver disease in animal models and humans exposed to EDCs. As numerous xenobiotics can activate CAR, its role in EDC-elicited adverse metabolic effects has gained much interest. Here, we review the key features and mechanisms of CAR as a xenobiotic-sensing receptor, species differences and selectivity of CAR ligands, contribution of CAR to regulation hepatic metabolism, and evidence for CAR-dependent EDC action therein.
Topics: Animals; Constitutive Androstane Receptor; Endocrine Disruptors; Humans; Inactivation, Metabolic; Liver; Metabolic Networks and Pathways; Mice; Rats; Receptors, Cytoplasmic and Nuclear; Transcription Factors; Xenobiotics
PubMed: 33076503
DOI: 10.3390/cells9102306 -
Frontiers in Pharmacology 2023Pharmacogenetics-informed drug prescribing is increasingly applied in clinical practice. Typically, drug metabolizing phenotypes are determined based on genetic test...
Pharmacogenetics-informed drug prescribing is increasingly applied in clinical practice. Typically, drug metabolizing phenotypes are determined based on genetic test results, whereupon dosage or drugs are adjusted. Drug-drug-interactions (DDIs) caused by concomitant medication can however cause mismatches between predicted and observed phenotypes (phenoconversion). Here we investigated the impact of genotype on the outcome of CYP2C19-dependent DDIs in human liver microsomes. Liver samples from 40 patients were included, and genotyped for *2, *3 and *17 variants. S-mephenytoin metabolism in microsomal fractions was used as proxy for CYP2C19 activity, and concordance between genotype-predicted and observed CYP2C19 phenotype was examined. Individual microsomes were subsequently co-exposed to fluvoxamine, voriconazole, omeprazole or pantoprazole to simulate DDIs. Maximal CYP2C19 activity (V) in genotype-predicted intermediate metabolizers (IMs; *1/*2 or *2/*17), rapid metabolizers (RMs; *1/*17) and ultrarapid metabolizers (UMs; *17/*17) was not different from V of predicted normal metabolizers (NMs; *1/*1). Conversely, *2/*2 genotyped-donors exhibited V rates ∼9% of NMs, confirming the genotype-predicted poor metabolizer (PM) phenotype. Categorizing CYP2C19 activity, we found a 40% concordance between genetically-predicted CYP2C19 phenotypes and measured phenotypes, indicating substantial phenoconversion. Eight patients (20%) exhibited CYP2C19 IM/PM phenotypes that were not predicted by their CYP2C19 genotype, of which six could be linked to the presence of diabetes or liver disease. In subsequent DDI experiments, CYP2C19 activity was inhibited by omeprazole (-37% ± 8%), voriconazole (-59% ± 4%) and fluvoxamine (-85% ± 2%), but not by pantoprazole (-2 ± 4%). The strength of CYP2C19 inhibitors remained unaffected by genotype, as similar percental declines in CYP2C19 activity and comparable metabolism-dependent inhibitory constants (K/K) of omeprazole were observed between CYP2C19 genotypes. However, the consequences of CYP2C19 inhibitor-mediated phenoconversion were different between genotypes. In example, voriconazole converted 50% of *1/*1 donors to a IM/PM phenotype, but only 14% of *1/*17 donors. Fluvoxamine converted all donors to phenotypic IMs/PMs, but *1/*17 (14%) were less likely to become PMs than *1/*1 (50%) or *1/*2 and *2/*17 (57%). This study suggests that the differential outcome of CYP2C19-mediated DDIs between genotypes are primarily dictated by basal CYP2C19 activity, that may in part be predicted by genotype but likely also depends on disease-related factors.
PubMed: 37361233
DOI: 10.3389/fphar.2023.1201906 -
International Journal of Molecular... Jan 2021The major determinants of drug or, al bioavailability are absorption and metabolism in the digestive tract. Genetic variations can cause significant differences in... (Review)
Review
The major determinants of drug or, al bioavailability are absorption and metabolism in the digestive tract. Genetic variations can cause significant differences in transporter and enzyme protein expression and function. The racial distribution of selected efflux transporter (i.e., Pgp, BCRP, MRP2) and metabolism enzyme (i.e., UGT1A1, UGT1A8) single nucleotide polymorphisms (SNPs) that are highly expressed in the digestive tract are reviewed in this paper with emphasis on the allele frequency and the impact on drug absorption, metabolism, and in vivo drug exposure. Additionally, preclinical and clinical models used to study the impact of transporter/enzyme SNPs on protein expression and function are also reviewed. The results showed that allele frequency of the major drug efflux transporters and the major intestinal metabolic enzymes are highly different in different races, leading to different drug disposition and exposure. The conclusion is that genetic polymorphism is frequently observed in different races and the related protein expression and drug absorption/metabolism function and drug in vivo exposure can be significantly affected, resulting in variations in drug response. Basic research on race-dependent drug absorption/metabolism is expected, and FDA regulations of drug dosing adjustment based on racial disparity are suggested.
Topics: ATP-Binding Cassette Transporters; Alleles; Animals; Biological Availability; Biological Transport; Biomarkers; Gastrointestinal Absorption; Gastrointestinal Tract; Gene Frequency; Humans; Inactivation, Metabolic; Metabolic Clearance Rate; Microsomes; Polymorphism, Single Nucleotide; Race Factors
PubMed: 33494365
DOI: 10.3390/ijms22031038 -
European Annals of Allergy and Clinical... Sep 2019Metabolomics can be used to explore altered metabolic pathways in asthma, giving insights into its pathophysiology. We aimed to review how metabolomics has been used to... (Review)
Review
Metabolomics can be used to explore altered metabolic pathways in asthma, giving insights into its pathophysiology. We aimed to review how metabolomics has been used to understand asthma by describing metabolic pathways under research and discussing clinical implications. The search was performed in PubMed, and studies published since 2000 using a metabolomics approach, were included. A total of 32 studies were analysed. Pathways related with cellular energy homeostasis, lipid metabolism and oxidative stress, immune and inflammatory processes and others were altered. Initial studies focused on biomarker discovery. But, metabolomics can be used to evaluate drug effects on specific pathways, to highlight pathways that can further develop in new targeted treatments and to identify differences according to asthma severity and phenotypes.
Topics: Asthma; Energy Metabolism; Homeostasis; Humans; Inflammation; Lipid Metabolism; Metabolomics; Oxidative Stress
PubMed: 31287260
DOI: 10.23822/EurAnnACI.1764-1489.101 -
International Journal of Oncology Feb 2021Serine/glycine biosynthesis and one‑carbon metabolism are crucial in sustaining cancer cell survival and rapid proliferation, and of high clinical relevance. Excessive... (Review)
Review
Serine/glycine biosynthesis and one‑carbon metabolism are crucial in sustaining cancer cell survival and rapid proliferation, and of high clinical relevance. Excessive activation of serine/glycine biosynthesis drives tumorigenesis and provides a single carbon unit for one‑carbon metabolism. One‑carbon metabolism, which is a complex cyclic metabolic network based on the chemical reaction of folate compounds, provides the necessary proteins, nucleic acids, lipids and other biological macromolecules to support tumor growth. Moreover, one‑carbon metabolism also maintains the redox homeostasis of the tumor microenvironment and provides substrates for the methylation reaction. The present study reviews the role of key enzymes with tumor‑promoting functions and important intermediates that are physiologically relevant to tumorigenesis in serine/glycine/one‑carbon metabolism pathways. The related regulatory mechanisms of action of the key enzymes and important intermediates in tumors are also discussed. It is hoped that investigations into these pathways will provide new translational opportunities for human cancer drug development, dietary interventions, and biomarker identification.
Topics: Animals; Antineoplastic Agents; Carbon; Carcinogenesis; Disease Models, Animal; Glycine; Humans; Metabolic Networks and Pathways; Methylation; Mice; Neoplasms; Oxidation-Reduction; Serine; Tumor Microenvironment; Warburg Effect, Oncologic
PubMed: 33491748
DOI: 10.3892/ijo.2020.5158 -
Antioxidants & Redox Signaling Dec 2020In humans, imbalances in the reduction-oxidation (redox) status of cells are associated with many pathological states. In addition, many therapeutics and prophylactics...
In humans, imbalances in the reduction-oxidation (redox) status of cells are associated with many pathological states. In addition, many therapeutics and prophylactics used as interventions for diverse pathologies either directly modulate oxidant levels or otherwise influence endogenous cellular redox systems. The cellular machineries that maintain redox homeostasis or that function within antioxidant defense systems rely heavily on the regulated reactivities of sulfur atoms either within or derived from the amino acids cysteine and methionine. Recent advances have substantially advanced our understanding of the complex and essential chemistry of biological sulfur-containing molecules. The redox machineries that maintain cellular homeostasis under diverse stresses can consume large amounts of energy to generate reducing power and/or large amounts of sulfur-containing nutrients to replenish or sustain intracellular stores. By understanding the metabolic pathways underlying these responses, one can better predict how to protect cells from specific stresses. Here, we summarize the current state of knowledge about the impacts of different stresses on cellular metabolism of sulfur-containing molecules. This analysis suggests that there remains more to be learned about how cells use sulfur chemistry to respond to stresses, which could in turn lead to advances in therapeutic interventions for some exposures or conditions.
Topics: Antioxidants; Cell Transformation, Neoplastic; Cysteine; Disease Susceptibility; Homeostasis; Humans; Metabolic Networks and Pathways; Methionine; Oxidation-Reduction; Oxidative Stress; Stress, Physiological; Sulfur
PubMed: 32799544
DOI: 10.1089/ars.2020.8151 -
Methods in Molecular Biology (Clifton,... 2021The complex enzyme kinetics displayed by drug-metabolizing cytochrome P450 enzymes (CYPs) (see Chapter 9 ) can, in part, be explained by an examination of their...
The complex enzyme kinetics displayed by drug-metabolizing cytochrome P450 enzymes (CYPs) (see Chapter 9 ) can, in part, be explained by an examination of their crystallographic protein structures. Fortunately, despite low sequence similarity between different families of drug-metabolizing CYPs, there exists a high degree of structural homology within the superfamily. This similarity in the protein fold allows for a direct comparison of the structural features of CYPs that contribute toward differences in substrate binding, heterotropic and homotropic cooperativity, and genetic variability in drug metabolism. In this chapter, we first provide an overview of the nomenclature and the role of structural features that are common in all CYPs. We then apply these definitions to understand the different substrate specificities and functions in the CYP3A, CYP2C, and CYP2D families of enzymes.
Topics: Crystallography, X-Ray; Cytochrome P-450 Enzyme System; Genetic Variation; Humans; Inactivation, Metabolic; Kinetics; Models, Molecular; Protein Folding; Protein Structure, Secondary; Substrate Specificity
PubMed: 34272695
DOI: 10.1007/978-1-0716-1554-6_7 -
Pharmacological Reports : PR Feb 2022Kidney diseases have become one of the most common health care problems. Due to a growing number of advanced aged patients with concomitant disorders the prevalence of... (Review)
Review
Kidney diseases have become one of the most common health care problems. Due to a growing number of advanced aged patients with concomitant disorders the prevalence of these diseases will increase over the coming decades. Despite available laboratory tests, accurate and rapid diagnosis of renal dysfunction has yet to be realized, and prognosis is uncertain. Moreover, data on diagnostic and prognostic markers in kidney diseases are lacking. The kynurenine (KYN) pathway is one of the routes of tryptophan (Trp) degradation, with biologically active substances presenting ambiguous properties. The KYN pathway is known to be highly dependent on immunological system activity. As the kidneys are one of the main organs involved in the formation, degradation and excretion of Trp end products, pathologies involving the kidneys result in KYN pathway activity disturbances. This review aims to summarize changes in the KYN pathway observed in the most common kidney disease, chronic kidney disease (CKD), with a special focus on diabetic kidney disease, acute kidney injury (AKI), glomerulonephritis and kidney graft function monitoring. Additionally, the importance of KYN pathway activity in kidney cancer pathogenesis is discussed, as are available pharmacological agents affecting KYN pathway activity in the kidney. Despite limited clinical data, the KYN pathway appears to be a promising target in the diagnosis and prognosis of kidney diseases. Modulation of KYN pathway activity by pharmacological agents should be considered in the treatment of kidney diseases.
Topics: Humans; Kidney Diseases; Kynurenine; Metabolic Networks and Pathways
PubMed: 34617264
DOI: 10.1007/s43440-021-00329-w -
European Journal of Cancer (Oxford,... Feb 2023Cell metabolism is characterised by the highly coordinated conversion of nutrients into energy and biomass. In solid cancers, hypoxia, nutrient deficiencies, and tumour... (Review)
Review
Cell metabolism is characterised by the highly coordinated conversion of nutrients into energy and biomass. In solid cancers, hypoxia, nutrient deficiencies, and tumour vasculature are incompatible with accelerated anabolic growth and require a rewiring of cancer cell metabolism. Driver gene mutations direct malignant cells away from oxidation to maximise energy production and biosynthesis while tumour-secreted factors degrade peripheral tissues to fuel disease progression and initiate metastasis. As it is vital to understand cancer cell metabolism and survival mechanisms, this review discusses the metabolic switch and current drug targets and clinical trials. In the future, metabolic markers may be included when phenotyping individual tumours to improve the therapeutic opportunities for personalised therapy.
Topics: Humans; Neoplasms; Energy Metabolism; Glycolysis; Mutation
PubMed: 36527974
DOI: 10.1016/j.ejca.2022.11.025