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Methods in Molecular Biology (Clifton,... 2023Mass spectrometry-based protein methodologies have revolutionized the field of analytical biochemistry and enable the identification of hundreds to thousands of proteins...
Mass spectrometry-based protein methodologies have revolutionized the field of analytical biochemistry and enable the identification of hundreds to thousands of proteins in biological fluids, cell lines, and tissue. This methodology requires the initial separation of a protein constellation, and this has been successfully achieved using gel-based techniques, particularly that of fluorescence two-dimensional difference gel electrophoresis (2D-DIGE). However, given the complexity of the proteome, fractionation techniques may be required to optimize the detection of low-abundance proteins, which are often underrepresented but which may represent important players in health and disease. Such subcellular fractionation protocols typically utilize density-gradient centrifugation and have enabled the enrichment of crude microsomes, the cytosol, the plasmalemma, the nuclei, and the mitochondria. In this chapter, we describe the experimental steps involved in the enrichment of crude microsomes from the skeletal muscle using differential centrifugation and subsequent verification of enrichment by gel electrophoresis and immunoblotting, prior to comparative 2D-DIGE analysis.
Topics: Proteomics; Two-Dimensional Difference Gel Electrophoresis; Proteome; Microsomes; Cytological Techniques; Electrophoresis, Gel, Two-Dimensional
PubMed: 36378450
DOI: 10.1007/978-1-0716-2831-7_24 -
Current Drug Metabolism 2021MIDD0301 is an oral asthma drug candidate that binds GABAA receptors on airway smooth muscle and immune cells. (Comparative Study)
Comparative Study
BACKGROUND
MIDD0301 is an oral asthma drug candidate that binds GABAA receptors on airway smooth muscle and immune cells.
OBJECTIVE
The objective of this study is to identify and quantify MIDD0301 metabolites in vitro and in vivo and determine the pharmacokinetics of oral, IP, and IV administered MIDD0301.
METHODS
In vitro conversion of MIDD0301 was performed using liver and kidney microsomes/S9 fractions followed by quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A LC-MS/MS method was developed using synthesized standards to quantify MIDD0301 and its metabolites in urine and feces. Blood, lung, and brain were harvested from animals that received MIDD0301 by oral, IP, and IV administration, followed by LCMS/ MS quantification. Imaging mass spectrometry was used to demonstrate the presence of MIDD0301 in the lung after oral administration.
RESULTS
MIDD0301 is stable in the presence of liver and kidney microsomes and S9 fractions for at least two hours. MIDD0301 undergoes conversion to the corresponding glucuronide and glucoside in the presence of conjugating cofactors. For IP and IV administration, unconjugated MIDD0301 together with significant amounts of MIDD0301 glucoside and MIDD0301 taurine were found in urine and feces. Less conjugation was observed following oral administration, with MIDD0301 glucuronide being the main metabolite. Pharmacokinetic quantification of MIDD0301 in blood, lung, and brain showed very low levels of MIDD0301 in the brain after oral, IV, or IP administration. The drug half-life in these tissues ranged between 4-6 hours for IP and oral and 1-2 hours for IV administration. Imaging mass spectrometry demonstrated that orally administered MIDD0301 distributes uniformly in the lung parenchyma.
CONCLUSION
MIDD0301 undergoes no phase I and moderate phase II metabolism.
Topics: Administration, Intravenous; Administration, Oral; Animals; Anti-Asthmatic Agents; Azepines; Chromatography, Liquid; Dogs; Female; Humans; Imidazoles; Injections, Intraperitoneal; Kidney; Lung; Mice; Microsomes; Microsomes, Liver; Rats; Tandem Mass Spectrometry; Tissue Distribution
PubMed: 34856893
DOI: 10.2174/1389200222666211202093841 -
Drug Metabolism and Disposition: the... Mar 2020The 20 uridine diphosphate glycosyl-transferases (UGTs) encoded in the human genome form an essential homeostatic network of overlapping catalytic functions that surveil...
The 20 uridine diphosphate glycosyl-transferases (UGTs) encoded in the human genome form an essential homeostatic network of overlapping catalytic functions that surveil and regulate the activity and clearance of scores of small molecule metabolites. Biochemical and biophysical UGT studies have been hampered by the inability to purify these membrane-bound proteins. Here, using cell-free expression and nanodisc technology, we assemble and purify to homogeneity the first UGT nanodisc-the human UGT2B7•nanodisc. The complex is readily isolated in milligram quantities. It is stable and its initial-rate parameters are identical within error to those associated with UGT2B7 in microsomal preparations (i.e., Supersomes). The high purity of the nanodisc preparation simplifies UGT assays, which allows complexities traditionally associated with microsomal assays (latency and the albumin effect) to be circumvented. Each nanodisc is shown to harbor a single UGT2B7 monomer. The methods described herein should be widely applicable to UGTs, and these findings are expected to set the stage for experimentalists to more freely explore the structure, function, and biology of this important area of phase II metabolism. SIGNIFICANCE STATEMENT: Lack of access to pure, catalytically competent human uridine diphosphate glucuronosyl-transferases (UGTs) has long been an impediment to biochemical and biophysical studies of this disease-relevant enzyme family. Here, we demonstrate this barrier can be removed using nanodisc technology-a human UGT2B7•nanodisc is assembled, purified to homogeneity, and shown to have activity comparable to microsomal UGT2B7.
Topics: Glucuronosyltransferase; Humans; Liver; Microsomes, Liver
PubMed: 31892527
DOI: 10.1124/dmd.119.089946 -
Drug Metabolism Reviews Aug 2022This year's review on bioactivation and reactivity began as a part of the annual review on biotransformation and bioactivation led by Cyrus Khojasteh (see references).... (Review)
Review
This year's review on bioactivation and reactivity began as a part of the annual review on biotransformation and bioactivation led by Cyrus Khojasteh (see references). Increased contributions from experts in the field led to the development of a stand alone edition for the first time this year focused specifically on bioactivation and reactivity. Our objective for this review is to highlight and share articles which we deem influential and significant regarding the development of covalent inhibitors, mechanisms of reactive metabolite formation, enzyme inactivation, and drug safety. Based on the selected articles, we created two sections: (1) reactivity and enzyme inactivation, and (2) bioactivation mechanisms and safety (Table 1). Several biotransformation experts have contributed to this effort from academic and industry settings.[Table: see text].
Topics: Biotransformation; Humans; Microsomes, Liver
PubMed: 35876116
DOI: 10.1080/03602532.2022.2097254 -
Planta Medica Sep 2023Oral preparations of (guacatonga) are used as antacid, analgesic, anti-inflammatory, and antiulcerogenic medicines. The clerodane diterpenes casearin B and...
Oral preparations of (guacatonga) are used as antacid, analgesic, anti-inflammatory, and antiulcerogenic medicines. The clerodane diterpenes casearin B and caseargrewiin F are major active compounds and . The oral bioavailability and metabolism of casearin B and caseargrewiin F were not previously investigated. We aimed to assess the stability of casearin B and caseargrewiin F in physiological conditions and their metabolism in human liver microsomes. The compounds were identified by UHPLC-QTOF-MS/MS and quantified by validated LC-MS methods. The stability of casearin B and caseargrewiin F in physiological conditions was assessed . Both diterpenes showed a fast degradation (p < 0.05) in simulated gastric fluid. Their metabolism was not mediated by cytochrome P-450 enzymes, but the depletion was inhibited by the esterase inhibitor NaF. Both diterpenes and their dialdehydes showed a octanol/water partition coefficient in the range of 3.6 to 4.0, suggesting high permeability. Metabolism kinetic data were fitted to the Michaelis-Menten profile with K values of 61.4 and 66.4 µM and V values of 327 and 648 nmol/min/mg of protein for casearin B and caseargrewiin F, respectively. Metabolism parameters in human liver microsomes were extrapolated to predict human hepatic clearance, and suggest that caseargrewiin F and casearin B have a high hepatic extraction ratio. In conclusion, our data suggest that caseargrewiin F and casearin B present low oral bioavailability due to extensive gastric degradation and high hepatic extraction.
Topics: Humans; Diterpenes, Clerodane; Tandem Mass Spectrometry; Liver; Microsomes, Liver
PubMed: 37084791
DOI: 10.1055/a-2078-5920 -
Pharmacology Research & Perspectives Jun 2022Fenfluramine (FFA) has potent antiseizure activity in severe, pharmacoresistant childhood-onset developmental and epileptic encephalopathies (e.g., Dravet syndrome). To... (Review)
Review
Fenfluramine (FFA) has potent antiseizure activity in severe, pharmacoresistant childhood-onset developmental and epileptic encephalopathies (e.g., Dravet syndrome). To assess risk of drug interaction affecting pharmacokinetics of FFA and its major metabolite, norfenfluramine (nFFA), we conducted in vitro metabolite characterization, reaction phenotyping, and drug transporter-mediated cellular uptake studies. FFA showed low in vitro clearance in human liver S9 fractions and in intestinal S9 fractions in all three species tested (t > 120 min). Two metabolites (nFFA and an N-oxide or a hydroxylamine) were detected in human liver microsomes versus six in dog and seven in rat liver microsomes; no metabolite was unique to humans. Selective CYP inhibitor studies showed FFA metabolism partially inhibited by quinidine (CYP2D6, 48%), phencyclidine (CYP2B6, 42%), and furafylline (CYP1A2, 32%) and, to a lesser extent (<15%), by tienilic acid (CYP2C9), esomeprazole (CYP2C19), and troleandomycin (CYP3A4/5). Incubation of nFFA with rCYP1A2, rCYP2B6, rCYP2C19, and rCYP2D6 resulted in 10%-20% metabolism and no clear inhibition of nFFA metabolism by any CYP-selective inhibitor. Reaction phenotyping showed metabolism of FFA by recombinant human cytochrome P450 (rCYP) enzymes rCYP2B6 (10%-21% disappearance for 1 and 10 µM FFA, respectively), rCYP1A2 (22%-23%), rCYP2C19 (49%-50%), and rCYP2D6 (59%-97%). Neither FFA nor nFFA was a drug transporter substrate. Results show FFA metabolism to nFFA occurs through multiple pathways of elimination. FFA dose adjustments may be needed when administered with strong inhibitors or inducers of multiple enzymes involved in FFA metabolism (e.g., stiripentol).
Topics: Animals; Cytochrome P-450 Enzyme System; Dogs; Drug Interactions; Fenfluramine; Humans; Microsomes, Liver; Norfenfluramine; Rats
PubMed: 35599345
DOI: 10.1002/prp2.958 -
Clinical Pharmacokinetics May 2021Drug metabolism is a critical process for the removal of unwanted substances from the body. In humans, approximately 80% of oxidative metabolism and almost 50% of the... (Review)
Review
Drug metabolism is a critical process for the removal of unwanted substances from the body. In humans, approximately 80% of oxidative metabolism and almost 50% of the overall elimination of commonly used drugs can be attributed to one or more of various cytochrome P450 (CYP) enzymes from CYP families 1-3. In addition to the basic metabolic effects for elimination, CYP enzymes in vivo are capable of affecting the treatment outcomes in many cases. Drug-metabolizing CYP enzymes are mainly expressed in the liver and intestine, the two principal drug oxidation and elimination organs, where they can significantly influence the drug action, safety, and bioavailability by mediating phase I metabolism and first-pass metabolism. Furthermore, CYP-mediated local drug metabolism in the sites of action may also have the potential to impact drug response, according to the literature in recent years. This article underlines the ability of CYP enzymes to influence treatment outcomes by discussing CYP-mediated diversified drug metabolism in primary metabolic sites (liver and intestine) and typical action sites (brain and tumors) according to their expression levels and metabolic activity. Moreover, intrinsic and extrinsic factors of personal differential CYP phenotypes that contribute to interindividual variation of treatment outcomes are also reviewed to introduce the multifarious pivotal role of CYP-mediated metabolism and clearance in drug therapy.
Topics: Cytochrome P-450 Enzyme System; Humans; Liver; Microsomes, Liver; Pharmaceutical Preparations; Treatment Outcome
PubMed: 33723723
DOI: 10.1007/s40262-021-01001-5 -
Pharmaceutical Biology Dec 2023Poziotinib and vonoprazan are two drugs mainly metabolized by CYP3A4. However, the drug-drug interaction between them is unknown.
CONTEXT
Poziotinib and vonoprazan are two drugs mainly metabolized by CYP3A4. However, the drug-drug interaction between them is unknown.
OBJECTIVE
To study the interaction mechanism and pharmacokinetics of poziotinib on vonoprazan.
MATERIALS AND METHODS
experiments were performed with rat liver microsomes (RLMs) and the contents of vonoprazan and its metabolite were then determined with UPLC-MS/MS after incubation of RLMs with vonoprazan and gradient concentrations of poziotinib. For the experiment, rats in the poziotinib treated group were given 5 mg/kg poziotinib by gavage once daily for 7 days, and the control group was only given 0.5% CMC-Na. On Day 8, tail venous blood was collected at different time points after the gavage administration of 10 mg/kg vonoprazan, and used for the quantification of vonoprazan and its metabolite. DAS and SPSS software were used for the pharmacokinetic and statistical analyses.
RESULTS
experimental data indicated that poziotinib inhibited the metabolism of vonoprazan (IC = 10.6 μM) in a mixed model of noncompetitive and uncompetitive inhibition. The inhibitory constant K was 0.574 μM and the binding constant αK was 2.77 μM. experiments revealed that the AUC (15.05 90.95 μg/mL·h) and AUC (15.05 91.99 μg/mL·h) of vonoprazan increased significantly with poziotinib pretreatment. The MRT of vonoprazan increased from 2.29 to 5.51 h, while the CLz/F value decreased from 162.67 to 25.84 L/kg·h after pretreatment with poziotinib.
CONCLUSIONS
Poziotinib could significantly inhibit the metabolism of vonoprazan and more care may be taken when co-administered in the clinic.
Topics: Rats; Animals; Chromatography, Liquid; Tandem Mass Spectrometry; Drug Interactions; Microsomes, Liver
PubMed: 36728978
DOI: 10.1080/13880209.2023.2173253 -
Methods in Molecular Biology (Clifton,... 2020The comparison of isolated plant cell membranous enclosures can be hampered if their extraction method differs, e.g., in regard to the utilized buffers, the tissue, or...
The comparison of isolated plant cell membranous enclosures can be hampered if their extraction method differs, e.g., in regard to the utilized buffers, the tissue, or the developmental stage of the plant. Thus, for comparable results, different cellular compartments should be isolated synchronously in one procedure. Here, we devise a workflow to isolate different organelles from one tissue, which is applicable to different eudicots such as Medicago x varia and Solanum lycopersicum. We describe this method for the isolation of different organelles from one plant tissue for the example of Arabidopsis thaliana. All compartments are retrieved by utilizing differential centrifugation with organelle-specific parameters.
Topics: Arabidopsis; Cell Fractionation; Centrifugation; Chloroplasts; Intracellular Membranes; Solanum lycopersicum; Medicago; Membranes; Microsomes; Mitochondria; Organelles; Plant Cells; Plant Extracts
PubMed: 32112316
DOI: 10.1007/978-1-0716-0373-4_6 -
ACS Chemical Biology Dec 2019The emergence and spread of antimicrobial resistance is a major public health threat, and there is an urgent need to develop new strategies to address the issue. In this...
The emergence and spread of antimicrobial resistance is a major public health threat, and there is an urgent need to develop new strategies to address the issue. In this study, the possibility of enhancing a whole cell based antibacterial library screen by increasing the dimensionality of the screening effort is explored using methicillin-resistant (MRSA) as the target organism. One dimension involved generating and screening a human liver microsome metabolized FDA approved drug library. Comparative screening of the un-metabolized (UM) and pre-metabolized (PM) libraries allows identification of intrinsically active agents from the UM library screen and of agents with active metabolites from the PM library screen. To further enhance this screening effort, it was combined with a -/+ resistant to antibiotic screen (-/+ cefoxitin; Cef). This allows the identification of agents that can act synergistically with the resistant to antibiotic. This approach revealed five compounds with substantially improved activity after metabolism and four compounds with substantial synergistic activity with cefoxitin. Capecitabine in particular only had significant antibacterial activity after metabolism. Its metabolites were isolated, identified, and characterized for spectrum of activity along with several other anticancer drugs with anti-MRSA activity. Floxuridine, gemcitabine, novobiocin, and rifaximin were identified as having substantial synergy with cefoxitin from the -/+Cef screens. Checkerboard assays verified synergy for these agents. Floxuridine demonstrated a particularly high degree of synergy with cefoxitin (FIC = 0.14). This study demonstrates how a dimensionally enhanced comparative screening effort can identify new antibacterial agents and strategies for countering antibacterial agent resistance.
Topics: Anti-Bacterial Agents; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Microsomes, Liver
PubMed: 31675203
DOI: 10.1021/acschembio.9b00745