BIOM-25. DETERMINATION OF LEVELS OF SMALL MOLECULAR WEIGHT THIOLS AND DISULFIDES IN MOUSE AND HUMAN NORMAL BRAIN AND GLIOBLASTOMA TISSUE
Ontology highlight
ABSTRACT:
SUBMITTER:
PROVIDER: S-EPMC9661058 | biostudies-literature | 2022 Nov
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A force field has been developed for molecular simulations of methanethiol, dimethyl sulfide, and dimethyl disulfide mixtures. The force field specifically attempts to balance the solvation and self-association of these solutes in solution mixtures with methanol. The force field is based on the Kirkwood-Buff (KB) theory of solutions and is parametrized using the KB integrals obtained from the experimental activity coefficients for the solution mixtures. The transferability of the force field was tested and confirmed by the accurate prediction of the activity coefficients for methanethiol/dimethyl sulfide solutions, which were not used in the initial parametrization of the force fields. The ideality of this latter solution is excellently reproduced. The applicability of the force field to simulations in water was corroborated with a reasonably accurate prediction for the low solubility of dimethyl sulfide in water. The aggregation of methanol molecules at low methanol mole fractions displayed by all the mixtures is reproduced and further analyzed.
| S-EPMC3141228 | biostudies-literature
Project description:Biothiols are extremely powerful antioxidants that protect cells against the effects of oxidative stress. They are also considered relevant disease biomarkers, specifically risk factors for cardiovascular disease. In this paper, a new procedure for the simultaneous determination of human serum albumin and low-molecular-weight thiols in plasma is described. The method is based on the pre-column derivatization of analytes with a thiol-specific fluorescence labeling reagent, monobromobimane, followed by separation and quantification through reversed-phase high-performance liquid chromatography with fluorescence detection (excitation, 378 nm; emission, 492 nm). Prior to the derivatization step, the oxidized thiols are converted to their reduced forms by reductive cleavage with sodium borohydride. Linearity in the detector response for total thiols was observed in the following ranges: 1.76-30.0 mg mL-1 for human serum albumin, 0.29-5.0 nmol mL-1 for α-lipoic acid, 1.16-35 nmol mL-1 for glutathione, 9.83-450.0 nmol mL-1 for cysteine, 0.55-40.0 nmol mL-1 for homocysteine, 0.34-50.0 nmol mL-1 for N-acetyl-L-cysteine, and 1.45-45.0 nmol mL-1 for cysteinylglycine. Recovery values of 85.16-119.48% were recorded for all the analytes. The developed method is sensitive, repeatable, and linear within the expected ranges of total thiols. The devised procedure can be applied to plasma samples to monitor biochemical processes in various pathophysiological states.
| S-EPMC8198679 | biostudies-literature
Project description:Endogenous thiols undergo rapid and reversible oxidation to disulfides when exposed to oxidants and are, therefore, suitable biomarkers of oxidative stress. However, accurate analysis of thiols in blood is frequently compromised by their artifactual oxidation during sample manipulation, which spuriously elevates the disulfide levels. Here, we describe a validated pre-analytical procedure that prevents both artifactual oxidation of thiols during sample manipulation and their oxidative decay for months in biosamples that are stored at -80°C. Addition of N-ethylmaleimide to blood samples from healthy donors was used to stabilize whole blood, red blood cells, platelets and plasma disulfides, whereas addition of citrate buffer followed by dilution of plasma with H2O was used to stabilize plasma thiols. The concentrations of thiols and disulfides were stable in all biosamples for at least 6 months when analyzed by UV/Vis HPLC at regular intervals. Only 3 ml of blood were needed to perform the analyses of thiols and disulfides in the different blood fractions. This pre-analytical procedure is reliable for use in both animal and human prospective studies. Its ease of implementation makes the method suitable for application to multicenter studies where blood samples are collected by different sites and personnel and are shipped to specific specialized laboratories.
| S-EPMC4829439 | biostudies-literature
Project description:Extracellular thiol/disulfide redox environments are highly regulated in healthy individuals and become oxidized in disease. This oxidation affects the function of cell surface receptors, ion channels, and structural proteins. Downstream signaling due to changes in extracellular redox potential can be studied using a redox clamp in which thiol and disulfide concentrations are varied to obtain a series of controlled redox potentials. Previous applications of this approach show that cell proliferation, apoptosis, and proinflammatory signaling respond to extracellular redox potential. Furthermore, gene expression and proteomic studies reveal the global nature of redox effects, and different cell types, for example, endothelial cells, fibroblasts, monocytes, and epithelial cells, show cell-specific redox responses. Application of the redox clamp to studies of different signaling pathways could enhance the understanding of redox transitions in many aspects of normal physiology and disease.
| S-EPMC3051281 | biostudies-literature
Project description:In light of the growing body of literature suggesting a beneficial effect of vitamin D on inflammatory response, we hypothesized that vitamin D affects serum ferritin (SF), a biomarker of inflammation. The objective of the present study is to examine the association of serum 25-hydroxyvitamin D [25(OH)D] with elevated SF concentrations indicative of inflammation as no earlier study has done so. Data from 5550 Canadian adults who participated in the 2012/2013 and the 2014/2015 Canadian Health Measures Surveys were analysed. We observed that 9.4% of Canadian adults have elevated SF concentrations and that 35.6% were vitamin D insufficient. Among Canadians with under/normal body weights, those with serum 25(OH)D ≥ 75 nmol/L relative to those with serum 25(OH)D < 50 nmol/L, were substantially less at risk for elevated SF concentrations (OR = 0.24; 95% CI = 0.06, 0.89; p = 0.034). We did not observe this association for overweight and obese Canadians. Canadians of older age, non-white ethnicity, males, those with income above $100,000, those who consumed alcohol, and those with high total cholesterol concentrations and elevated blood pressures were more likely to have elevated SF concentrations. Serum 25(OH)D ≥ 75 nmol/L is likely to provoke anti-inflammatory benefits, but intervention studies that achieve high 25(OH)D concentrations and with long follow up are needed to establish the role of vitamin D on SF.
| S-EPMC6405102 | biostudies-literature
Project description:Abstract The nuclear export protein exportin 1 (XPO1) is overexpressed in many cancers, including GBM. Selinexor is an inhibitor of XPO1 that crosses the blood-brain-barrier and targets cancer cells by sequestering tumor suppressor proteins and oncoprotein mRNAs in the nucleus, inducing cancer cell apoptosis. We previously reported encouraging results from a phase II trial of selinexor for molecularly unselected patients with recurrent GBM (ASCO 2019). Pre-treatment tumors from 57 patients were exome and RNA sequenced to explore molecular correlates of response, in a hypothesis generating, post-hoc, exploratory analysis. We compared overall survival (OS) and progression-free survival (PFS) between mutated and wild-type patients. Two mutated genes were associated with longer survival in selinexor treated patients: DOCK8 (n=7; PFS, P=0.013, hazard ratio [HR]=3.75 [1.32–10.62]; overall survival, P=0.009, HR=15.39 [2.00–118.34]) and PDX1 (n=5, PFS, P=0.014, HR=4.468 [1.361–14.670]). Other commonly mutated genes in glioma, including IDH1 (n=9) were observed but not associated with survival. RNAseq data were used to infer differential protein activities, which were input into a machine learning model that compared patients with selinexor sensitive disease (best response of partial or complete response, n=7) and resistant disease (best response of progressive disease, n=23). We found the inferred activities of three proteins emerged as the most associated with response and could be combined in a model to accurately predict benefit from selinexor treatment (area under the ROC curve from leave one out cross validation = 0.89 permutation test P< 0.04). The three proteins were ZC3H12A (also called MCPIP-1), a negative regulator of inflammation; RAB43, a member of the RAS family that binds GTP and regulates vesicle trafficking, and SOCS3, a suppressor of cytokine signaling that can antagonize JAK/STAT signaling. Together these data identified mutations and proteins activities for identifying patients most likely to benefit from selinexor treatment. Further studies are required for validation. ClinicalTrials.gov:NCT01986348.
| S-EPMC7650493 | biostudies-literature
Project description:Pooled samples of primary GBM tissues, primary cultures, and normal tissues were analyzed by MPSS. 2 Samples
| S-ECPF-GEOD-14878 | biostudies-other
Project description:Sulfur amino acid nutrition and metabolism are linked to animal disease. While validated methods for the determination of amino thiol levels in plasma or serum are available, there is a dearth of validated methods for their measurement in tissue. A robust and reproducible ultra-high performance liquid chromatography method has been validated for the simultaneous determination of concentrations of cysteine (Cys), cysteinylglycine (CysGly), homocysteine (Hcys), γ-glutamylcysteine (γ-GluCys), and glutathione (GSH) in pig tissue. Tissue was homogenized and deproteinized with trichloroacetic acid. Amino thiols in the acid-soluble fraction of the tissue homogenate were reduced with tris-(2-carboxyethyl)-phosphine hydrochloride and derivatized with 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F). Amino thiols were resolved under reversed-phase gradient conditions on a Waters Acquity BEH C18 column (1.7 µm, 2.1 mm × 100 mm) within 4.5 min and detected with fluorescence. The peak area ratio of analyte to 2-mercaptopropionylglycine internal standard, added to external calibration standards and samples, was used to develop linear calibration curves. Linear calibrations were performed over the range of 15-1,500 nmol/g for Cys, CysGly, Hcys, and γ-GluCys and 150-15,000 nmol/g for GSH. Linearity, lower limit of detection, lower limit of quantitation, accuracy, precision, sample stability, and carryover were evaluated. We demonstrate excellent linearity for all analytes within their respective concentration range (r2 > 0.99) and excellent recovery of amino thiols from spiked samples (mean ± SD across tissues; Cys, 100.0 ± 2.2%; CysGly, 95.4 ± 5.1%; Hcys, 96.6 ± 2.0%; γ-GluCys, 102.2 ± 2.7%; and GSH, 100.6 ± 3.3%). The intra-day and inter-day precisions did not exceed 5% and 10%, respectively. Repeated freezing and thawing of tissue homogenate did not affect measured amino thiol concentrations, ABD-labeled amino thiols were stable for 1 wk after derivatization, and there was no sample carryover across consecutive injections. We confirm the identity of each ABD-labeled amino thiol with Orbitrap mass spectrometry. Finally, we apply the method to the determination of amino thiol concentrations in liver and jejunum tissues in newly weaned pigs and show that despite elevated Cys and maintained GSH concentrations in liver, both γ-GluCys and GSH decline in jejunum of weaned pigs.
| S-EPMC9940738 | biostudies-literature
Project description:Methylmercury (MeHg) is one of the most potent neurotoxins. It is produced in nature through the methylation of inorganic divalent mercury (HgII) by phylogenetically diverse anaerobic microbes. The mechanistic understanding of the processes that govern the extent of bacterial export of MeHg, its bioaccumulation, and bio-toxicity depends on accurate quantification of its species, especially its complexation with low molecular mass thiols; organometallic complexes that are difficult to detect and measure in natural conditions. Here, we report the development of a novel analytical method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine 13 MeHg complexes with important thiol compounds which have been observed in the environment and in biological systems. By using online preconcentration via solid phase extraction (SPE), the method offers picomolar (12-530 pM) detection limits, the lowest reported so far for the determination of MeHg compounds. Among three different SPE materials, a weak cation exchange phase showed the best efficiency at a low pH of 2.5. We further report the presence of MeHg-cysteine, MeHg-cysteamine, MeHg-penicillamine, MeHg-cysteinylglycine, and MeHg-glutamylcysteine as the predominant MeHg-thiol complexes in the extracellular milieu of an important HgII methylating bacterium, Geobacter sulfurreducens PCA, exposed to 100 nM of HgII.
| S-EPMC7026298 | biostudies-literature
Project description:Oxidative modifications of cysteine residues are an important component in signaling pathways, enzymatic regulation, and redox homeostasis. Current direct and indirect methods detect specific modifications and a general binary population of "free" or "oxidized" cysteines, respectively. In an effort to combine both direct and indirect detection strategies, here we developed a method that we designate isotopic tagging of oxidized and reduced cysteines (iTORC). This method uses synthetic molecules for rapid isotopic coding of sulfenic acids, reduced cysteines, and disulfides in cells. Our approach utilizes isotopically distinct benzothiazine and halogenated benzothiazine probes to sequentially alkylate sulfenic acids and then free thiols and, finally, after a reduction step, cysteines oxidized to disulfides or other phosphine-reducible states. We ascertained that the iodinated benzothiazine probe has reduced cross-reactivity toward primary amines and is highly reactive with the cysteine of GSH, with a calculated rate constant of 2 × 105 m-1 s-1 (pH 8.0, 23 °C) (i.e. 10-20 times faster than N-ethylmaleimide). We applied iTORC to a mouse hepatocyte lysate to identify known sulfenylated and disulfide-bonded proteins, including elongation factor 1-α1 and mouse serum albumin, and found that iTORC reliably detected their expected oxidation status. This method can be easily employed to study the effects of oxidants on recombinant proteins and cell and tissue extracts, and the efficiencies of the alkylating agents enable completion of all three labeling steps within 2 h. In summary, we demonstrate here that halogenated benzothiazine-based alkylating agents can be utilized to rapidly measure the cellular thiol status in cells.
| S-EPMC6484142 | biostudies-literature