HILIC-MS Rat Brain Analysis, A New Approach for the Study of Ischemic Attack.
Ontology highlight
ABSTRACT:
SUBMITTER: Miekus N
PROVIDER: S-EPMC5558183 | biostudies-other | 2017
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Expanding metabolome coverage to include complex lipids and polar metabolites is essential in the generation of well-founded hypotheses in biological assays. Traditionally, lipid extraction is performed by liquid-liquid extraction using either methyl-tert-butyl ether (MTBE) or chloroform, and polar metabolite extraction using methanol. Here, we evaluated the performance of single-step sample preparation methods for simultaneous extraction of the complex lipidome and polar metabolome from human plasma. The method performance was evaluated using high-coverage Hydrophilic Interaction Liquid Chromatography-ESI coupled to tandem mass spectrometry (HILIC-ESI-MS/MS) methodology targeting a panel of 1159 lipids and 374 polar metabolites. The criteria used for method evaluation comprised protein precipitation efficiency, and relative MS signal abundance and repeatability of detectable lipid and polar metabolites in human plasma. Among the tested methods, the isopropanol (IPA) and 1-butanol:methanol (BUME) mixtures were selected as the best compromises for the simultaneous extraction of complex lipids and polar metabolites, allowing for the detection of 584 lipid species and 116 polar metabolites. The extraction with IPA showed the greatest reproducibility with the highest number of lipid species detected with the coefficient of variation (CV) < 30%. Besides this difference, both IPA and BUME allowed for the high-throughput extraction and reproducible measurement of a large panel of complex lipids and polar metabolites, thus warranting their application in large-scale human population studies.
| S-EPMC7760228 | biostudies-literature
Project description:Recent progress in top-down proteomics has driven the demand for chromatographic methods compatible with mass spectrometry (MS) that can separate intact proteins. Hydrophilic interaction liquid chromatography (HILIC) has recently shown good potential for the characterization of glycoforms of intact proteins. In the present study, we demonstrate that HILIC can separate a wide range of proteins exhibiting orthogonal selectivity with respect to reversed-phase LC (RPLC). However, the application of HILIC to the analysis of low abundance proteins (e.g., in proteomics analysis) is hampered by low volume loadability, hindering down-scaling of the method to column diameters below 2.1 mm. Moreover, HILIC-MS sensitivity is decreased due to ion suppression from the trifluoroacetic acid (TFA) often used as the ion-pair agent to improve the selectivity and efficiency in the analysis of glycoproteins. Here, we introduce a capillary-based HILIC-MS method that overcomes these problems. Our method uses RPLC trap-columns to load and inject the sample, circumventing issues of protein solubility and volume loadability in capillary columns (200 μm ID). The low flow rates and use of a dopant gas in the electrospray interface improve protein-ionization efficiencies and reduce suppression by TFA. Overall, this allows the separation and detection of small protein quantities (down to 5 ng injected on column) as indicated by the analysis of a mixture of model proteins. The potential of the new capillary HILIC-MS is demonstrated by the analysis of a complex cell lysate.
| S-EPMC5990932 | biostudies-literature
Project description:INTRODUCTION:As large scale metabolic phenotyping is increasingly employed in preclinical studies and in the investigation of human health and disease the current LC-MS/MS profiling methodologies adopted for large sample sets can result in lengthy analysis times, putting strain on available resources. As a result of these pressures rapid methods of untargeted analysis may have value where large numbers of samples require screening. OBJECTIVES:To develop, characterise and evaluate a rapid UHP-HILIC-MS-based method for the analysis of polar metabolites in rat urine and then extend the capabilities of this approach by the addition of IMS to the system. METHODS:A rapid untargeted HILIC LC-MS/MS profiling method for the analysis of small polar molecules has been developed. The 3.3 min separation used a Waters BEH amide (1 mm ID) analytical column on a Waters Synapt G2-Si Q-Tof enabled with ion mobility spectrometry (IMS). The methodology, was applied to the metabolic profiling of a series of rodent urine samples from vehicle-treated control rats and animals administered tienilic acid. The same separation was subsequently linked to IMS and MS to evaluate the benefits that IMS might provide for metabolome characterisation. RESULTS:The rapid HILIC-MS method was successfully applied to rapid analysis of rat urine and found, based on the data generated from the data acquired for the pooled quality control samples analysed at regular intervals throughout the analysis, to be robust. Peak area and retention times for the compounds detected in these samples showed good reproducibility across the batch. When used to profile the urine samples obtained from vehicle-dosed control and those administered tienilic acid the HILIC-MS method detected 3007 mass/retention time features. Analysis of the same samples using HILIC-IMS-MS enabled the detection of 6711 features. Provisional metabolite identification for a number of compounds was performed using the high collision energy MS/MS information compared against the Metlin MS/MS database and, in addition, both calculated and measured CCS values from an experimentally derived CCS database. CONCLUSION:A rapid metabolic profiling method for the analysis of polar metabolites has been developed. The method has the advantages of speed and both reducing sample and solvent consumption compared to conventional profiling methods. The addition of IMS added an additional dimension for feature detection and the identification of metabolites.
| S-EPMC6342856 | biostudies-literature
Project description:Heparan sulfate (HS) mediates a wide range of protein binding interactions key to normal and pathological physiology. Though liquid chromatography coupled with mass spectrometry (LC-MS) based disaccharide composition analysis is able to profile changes in HS composition, the heterogeneity of modifications and the labile sulfate group present major challenges for liquid chromatography tandem mass spectrometry (LC-MS/MS) sequencing of the HS oligosaccharides that represent protein binding determinants. Here, we report online LC-MS/MS sequencing of HS oligosaccharides using hydrophilic interaction liquid chromatography (HILIC) and negative electron transfer dissociation (NETD). A series of synthetic HS oligosaccharides varying in chain length (tetramers and hexamers), number of sulfate groups (3-7), sulfate patterns (sulfate positional isomers), and uronic acid epimerization (epimers) were separated and sequenced. The LC elution order of isomeric compounds was associated with their fine structure. The application of an online cation exchange device (ion suppressor) enhanced the precursor charge states, and the subsequent NETD produced abundant glycosidic fragments, allowing the characterization of both lowly sulfated and highly sulfated HS oligosaccharides. Furthermore, the diagnostic cross-ring ions differentiated the 6-O sulfation and 3-O sulfation, allowing unambiguous structural assignment. Collectively, this LC-NETD-MS/MS method is a powerful tool for sequencing of heterogeneous HS mixtures and is applicable for the differentiation of both isomers and epimers, for the characterization of saccharide mixtures with a varying extent of sulfation and even for the determination of both predominant and rare modification motifs. Thus, LC-NETD-MS/MS has great potential for further application to biological studies.
| S-EPMC7161314 | biostudies-literature
Project description:Background: Transient ischemic attack (TIA) is an important risk factor for stroke. Despite the transient episodes of clinical symptoms, brain alterations are still observed in patients with TIA. However, the functional mechanism of transient ischemia is still unclear. Here, we employed resting-state functional magnetic resonance imaging (rs-fMRI) to explore the functional abnormalities in patients with TIA. Methods: 48 TIA patients and 41 age- and sex-matched healthy controls (HCs) were enrolled in the study. For each participant, we collected rs-fMRI data and clinical/physiological/biochemical data. Amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality (DC) were then calculated. Two sample t-tests were performed to compare the ALFF, ReHo, and DC maps between the two groups. Furthermore, a correlation analysis was performed to explore the relationship between local brain abnormalities and clinical/physiological/biochemical characteristics tests in TIA patients. Results: Compared with the HCs, the TIA patients exhibited decreased ALFF in the left middle temporal gyrus, decreased DC in the triangular part of right inferior frontal gyrus, and no significant statistical difference in ReHo. No correlation was found between local abnormalities and clinical/physiological/biochemical scores in the patients with TIA. Conclusion: Collectively, we found decreased ALFF and DC in patients with TIA which provide evidence for local brain dysfunctions and may help to understand the pathological mechanism for the disease.
| S-EPMC6371034 | biostudies-literature
Project description:BackgroundTransient ischemic attack (TIA) provides a unique opportunity to optimize secondary preventive treatments to avoid subsequent ischemic stroke (SIS). Although atrial fibrillation (AF) is the leading cause of cardioembolism in IS and anticoagulation prevents stroke recurrence (SR), limited data exists about the risk of new-diagnosed AF (NDAF) after TIA and the consequences of the diagnostic delay. The aim of our study was to determine this risk in a cohort of TIA patients with long-term follow-up.MethodsWe carried out a prospective cohort study of 723 consecutive TIA patients from January 2006 to June 2010. Median follow-up was 6.5 (5.0-9.6) years. In a subgroup of 204 (28.2%) consecutive patients, a panel of biomarkers was assessed during the first 24 h of the onset of symptoms. Multivariate analyses were performed to find out the associated factors of NDAF. Kaplan-Meier analysis was also performed to analyzed risk of SIS.ResultsNDAF was indentified in 116 (16.0%) patients: 42 (36.2%) during admission, 18 (15.5%) within first year, 29 (25%) between one and five years and 27 (23.3%) beyond 5 years. NDAF was associated with sex (female) [hazard ratio (HR) 1.61 (95% CI, 1.07- 2.41)], age [[HR 1.05 (95% CI, 1.03-1.07)], previous ischemic heart disease (IHD) [HR 1.84, (95% CI 1.15-2.97)] and cortical DWI pattern [HR 2.81 (95% CI, 1.87-4.21)]. In the Kaplan-Meier analysis, NT-proBNP ≥ 218.2 pg/ml (log-rank test P < 0.001) was associated with significant risk of NDAF during the first 5 years of follow-up. Patients with NDAF after admission and before 5 years of follow-up had the highest risk of SIS (P = 0.002).ConclusionThe risk of NDAF after TIA is clinically relevant. We identified clinical and neuroimaging factors of NDAF. In addition, NT-proBNP was related to NDAF. Our results can be used to evaluate the benefit of long-term cardiac monitoring in selected patients.
| S-EPMC9331650 | biostudies-literature
Project description:Brain ischemia, also termed cerebral ischemia, is a condition in which there is insufficient blood flow to the brain to meet metabolic demand, and results in brain tissue death (cerebral infarction) due to poor oxygen supply (cerebral hypoxia). Our group is interested in the protective effects of neuropeptides for alleviating brain ischemia, and mechanisms therein. However, before proceeding to the neuroprotection aspect of our research, we initiated a study with a primary aim to investigate the molecular responses at the level of gene expression in ischemic brain tissue. To do so, we used permanent middle cerebral artery occlusion (PMCAO) model mice in combination with high-throughput DNA microarray analysis on an Agilent microarray platform. Briefly, saline injected mice brain in sham (control, n=3) and PMCAO (treatment, n=3) mice were dissected into left (contralateral) and right hemispheres (ipsilateral) at two time points, 6 and 24 h after injection. The ipsilateral hemisphere shows ischemia, within 24 h, and is marked by cell death as visualized by TTC staining. Tissues were ground into fine powder with liquid nitrogen and total RNA was extracted, followed by quality check using gel electrophoresis and cDNA synthesis in conjunction with RT-PCR using certain marker genes. The obtained good quality total RNA from ipsilateral hemisphere was used for DNA microarray analysis on a mouse (Mus musculus) whole genome 4x44K DNA chip by using the dye-swap approach. Results revealed a large number of changed gene expressions at both 6 (1237 up- and 620 down-regulated) and 24 h (2759 up- and 2102 down-regulated). 792 and 167 genes were found to be commonly up- and down-regulated 6 and 24 h post-ischemia, respectively. Functional categorization using the gene ontology (GO, MGD/AMIGO) of these gene expressions revealed major categories of cellular processes, biological regulation, regulation of biological processes, metabolic processes, and response to stimulus. In addition, RT-PCR using specific primers of randomly selected genes was used to validate the changed gene expressions. This study provides the first inventory of ischemia-related transcriptome in mouse brain. For appropriate control to the PMCAO model, mice were anesthetized with 4% isoflurane (induction) and 2% isoflurane (maintenance) in a 30% O2 and 70% N2O gas mixture via a face mask. An incision was then made in the cervical skin followed by opening of salivary gland, and visualization of the right common carotid artery. The external carotid artery was exposed through a midline cervical incision, and subsequently, the wound was closed by sutures. For the PMCAO model, we used the intraluminal filament technique, where a 7-0 monofilament nylon suture with its tip slightly rounded by heating was inserted into the common carotid artery followed by placement into the middle cerebral artery. In both the control and PMCAO model, saline (0.9% NaCl) was injected into the intracerebroventricle, and the animals were returned to their cages. A total of eight groups were prepared with three mice each in the control (4 groups) and PMCAO model (4 groups). After 6 and 24 h post-injection of saline, mice were removed from the cages and decapitated using scissors, and the whole brains were carefully dissected on ice. The left (contralateral) and right (ipsilateral) hemispheres were separated and placed in 2 mL Eppendorf tubes followed by quickly immersing the tubes in liquid nitrogen (Lq. N2), and then stored in -80ºC prior to further analysis. A mouse 4 x 44K whole genome oligo DNA microarray chip (G4122F, Agilent Technologies, Palo Alto, CA, USA) was used for global gene expression analysis using the contralateral hemispheres. The effects of ischemia were checked over the SHAM control mice at 6 and 24 h post-saline injection.
2012-03-31 | E-GEOD-28201 | biostudies-arrayexpress
Project description:Remote ischemic preconditioning's (RIPC) ability to render the myocardium resistant to subsequent prolonged ischemia is now clearly established in different species, including humans. Strong evidence suggests that circulating humoral mediators play a key role in signal transduction, but their identities still need to be established. Our study sought to identify potential circulating RIPC mediators using a proteomic approach. Rats were exposed to 10-min limb ischemia followed by 5- (RIPC 5') or 10-min (RIPC 10') reperfusion prior to blood sampling. The control group only underwent blood sampling. Plasma samples were isolated for proteomic analysis using surface-enhanced laser desorption and ionization - time of flight - mass spectrometry (SELDI-TOF-MS). A total of seven proteins, including haptoglobin and transthyretin, were detected as up- or down-regulated in response to RIPC. These proteins had previously been identified as associated with organ protection, anti-inflammation, and various cellular and molecular responses to ischemia. In conclusion, this study indicates that RIPC results in significant modulations of plasma proteome.
| S-EPMC3890329 | biostudies-literature
Project description:An untargeted metabolomics strategy using hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) was developed in this work enabling the study of the coffee roasting process. Green coffee beans and coffee beans submitted to three different roasting degrees (light, medium, and strong) were analyzed. Chromatographic separation was carried out using water containing 10 mM ammonium formate with 0.2 % formic acid (mobile phase A) and acetonitrile containing 10 mM ammonium formate with 0.2 % formic acid (mobile phase B). A total of 93 molecular features were considered from which 31 were chosen as the most statistically significant using variable in the projection values. 13 metabolites were tentatively identified as potential biomarkers of the coffee roasting process using this metabolomic platform. Results obtained in this work were complementary to those achieved using orthogonal techniques such as reversed-phase liquid chromatography-mass spectrometry (RPLC-MS) and capillary electrophoresis-mass spectrometry (CE-MS) since only one metabolite was found to be common between HILIC-MS and RPLC-MS platforms (caffeoylshikimic acid isomer) and other between HILIC-MS and CE-MS platforms (choline). On the basis of these results, an untargeted metabolomics multiplatform is proposed in this work based on the integration of the three orthogonal techniques as a powerful tool to expand the coverage of the roasted coffee metabolome.
| S-EPMC7070313 | biostudies-literature
Project description:Brain ischemia, also termed cerebral ischemia, is a condition in which there is insufficient blood flow to the brain to meet metabolic demand, and results in brain tissue death (cerebral infarction) due to poor oxygen supply (cerebral hypoxia). Our group is interested in the protective effects of neuropeptides for alleviating brain ischemia, and mechanisms therein. However, before proceeding to the neuroprotection aspect of our research, we initiated a study with a primary aim to investigate the molecular responses at the level of gene expression in ischemic brain tissue. To do so, we used permanent middle cerebral artery occlusion (PMCAO) model mice in combination with high-throughput DNA microarray analysis on an Agilent microarray platform. Briefly, saline injected mice brain in sham (control, n=3) and PMCAO (treatment, n=3) mice were dissected into left (contralateral) and right hemispheres (ipsilateral) at two time points, 6 and 24 h after injection. The ipsilateral hemisphere shows ischemia, within 24 h, and is marked by cell death as visualized by TTC staining. Tissues were ground into fine powder with liquid nitrogen and total RNA was extracted, followed by quality check using gel electrophoresis and cDNA synthesis in conjunction with RT-PCR using certain marker genes. The obtained good quality total RNA from ipsilateral hemisphere was used for DNA microarray analysis on a mouse (Mus musculus) whole genome 4x44K DNA chip by using the dye-swap approach. Results revealed a large number of changed gene expressions at both 6 (1237 up- and 620 down-regulated) and 24 h (2759 up- and 2102 down-regulated). 792 and 167 genes were found to be commonly up- and down-regulated 6 and 24 h post-ischemia, respectively. Functional categorization using the gene ontology (GO, MGD/AMIGO) of these gene expressions revealed major categories of cellular processes, biological regulation, regulation of biological processes, metabolic processes, and response to stimulus. In addition, RT-PCR using specific primers of randomly selected genes was used to validate the changed gene expressions. This study provides the first inventory of ischemia-related transcriptome in mouse brain.
2012-04-01 | GSE28201 | GEO