Hydrophilic Metabolites Research Articles

Simple and Rapid (Extraction) Protocol for NMR Metabolomics-Direct Measurement of Hydrophilic and Hydrophobic Metabolites Using Slice Selection.

Investigating the metabolic profiles of solid sample materials with solution nuclear magnetic resonance (NMR) spectroscopy requires the extraction of these metabolites. This is commonly done by using two immiscible solvents such as water and chloroform for extraction. Subsequent solvent removal makes these extraction procedures very time-consuming. To shorten the preparation time of the NMR sample, the following protocol is proposed: the metabolites from a solid or liquid sample are extracted directly in the NMR tube, the NMR tube is centrifuged, and the metabolite profiles in the aqueous and organic phases are determined by using slice-selective proton NMR experiments. This protocol was tested with 11 black teas and 11 green teas, which can be easily distinguished by their metabolic profiles in the aqueous phase. As a test case for liquid samples, 29 milk samples were investigated. The geographical origin of the diaries where the milk was processed could not be determined unequivocally from the metabolic profiles of the hydrophilic metabolites; however, this was easily seen in the lipid profiles. As shown for the different test samples, the extraction protocol in combination with slice-selection NMR experiments is suitable for metabolic investigations. Because samples are rapidly processed, this approach can be used to explore different extraction strategies for metabolite isolation.

Relationship between Standard Uptake Values of Positron Emission Tomography/Computed Tomography and Salivary Metabolites in Oral Cancer: A Pilot Study.

18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) is usually used for staging or evaluation of treatment response rather than for cancer screening. However, 18F-FDG PET/CT has also been used in Japan for cancer screening in people with no cancer symptoms, and accumulating evidence supports this application of 18F-FDG PET/CT. Previously, we have observed a correlation between the saliva and tumor metabolomic profiles in patients with oral cancer. Hence, if salivary metabolites demonstrate a significant correlation with PET parameters such as the maximum standardized uptake value (SUVmax), they may have the potential to be used as a screening tool before PET/CT to identify patients with high SUVmax. Hence, in this study, we aimed to explore the relationship between salivary metabolites and SUVmax of 18F-FDG PET/CT using previously collected data. 18F-FDG PET/CT was performed for staging 26 patients with oral cancer. The collected data were integrated and analyzed along with quantified salivary hydrophilic metabolites obtained from the same patients with oral cancer and controls (n = 44). In total, 11 metabolites showed significant correlations with SUVmax in the delayed phases. A multiple logistic regression model of the two metabolites showed the ability to discriminate between patients with oral cancer and controls, with an area under the receiver operating characteristic curve of 0.738 (p = 0.001). This study uniquely confirmed a relationship between salivary metabolites and SUVmax of PET/CT in patients with oral cancer; salivary metabolites were significantly correlated with SUVmax. These salivary metabolites can be used as a screening tool before PET/CT to identify patients with high SUVmax, i.e., to detect the presence of oral cancer.

Urinary charged metabolite profiling of colorectal cancer using capillary electrophoresis-mass spectrometry

Colorectal cancer (CRC) has increasing global prevalence and poor prognostic outcomes, and the development of low- or less invasive screening tests is urgently required. Urine is an ideal biofluid that can be collected non-invasively and contains various metabolite biomarkers. To understand the metabolomic profiles of different stages of CRC, we conducted metabolomic profiling of urinary samples. Capillary electrophoresis-time-of-flight mass spectrometry was used to quantify hydrophilic metabolites in 247 subjects with stage 0 to IV CRC or polyps, and healthy controls. The 154 identified and quantified metabolites included metabolites of glycolysis, TCA cycle, amino acids, urea cycle, and polyamine pathways. The concentrations of these metabolites gradually increased with the stage, and samples of CRC stage IV especially showed a large difference compared to other stages. Polyps and CRC also showed different concentration patterns. We also assessed the differentiation ability of these metabolites. A multiple logistic regression model using three metabolites was developed with a randomly designated training dataset and validated using the remaining data to differentiate CRC and polys from healthy controls based on a panel of urinary metabolites. These data highlight the changes in metabolites from early to late stage of CRC and also the differences between CRC and polyps.

Elucidation of Gut Microbiota-Associated Lipids Using LC-MS/MS and 16S rRNA Sequence Analyses.

SummaryHost-microbiota interactions create a unique metabolic milieu that modulates intestinal environments. Integration of 16S ribosomal RNA (rRNA) sequences and mass spectrometry (MS)-based lipidomics has a great potential to reveal the relationship between bacterial composition and the complex metabolic network in the gut. In this study, we conducted untargeted lipidomics followed by a feature-based molecular MS/MS spectral networking to characterize gut bacteria-dependent lipid subclasses in mice. An estimated 24.8% of lipid molecules in feces were microbiota-dependent, as judged by > 10-fold decrease in antibiotic-treated mice. Among these, there was a series of unique and microbiota-related lipid structures, including acyl alpha-hydroxyl fatty acid (AAHFA) that was newly identified in this study. Based on the integrated analysis of 985 lipid profiles and 16S rRNA sequence data providing 2,494 operational taxonomic units, we could successfully predict the bacterial species responsible for the biosynthesis of these unique lipids, including AAHFA.

Metabolic Profiling of Primary Metabolites and Galantamine Biosynthesis in Wounded Lycoris radiata Callus.

Plants are continuously exposed to abiotic and biotic factors that lead to wounding stress. Different plants exhibit diverse defense mechanisms through which various important metabolites are synthesized. Humans can exploit these mechanisms to improve the efficacy of existing drugs and to develop new ones. Most previous studies have focused on the effects of wounding stress on the different plant parts, such as leaves, stems, and roots. To date, however, no study has investigated the accumulation of primary and galantamine content following the exposure of a callus to wounding stress. Therefore, in the present study, we exposed Lycoris radiata calli to wounding stress and assessed the expression levels of several genes involved in metabolic pathways at various time points (0, 3, 6, 12, 24, 48, 72, and 96 h of exposure). Furthermore, we quantify the primary and galantamine content using gas chromatography–time-of-flight mass spectrometry and the high-performance liquid chromatography qRT-PCR analysis of eight galantamine pathway genes (LrPAL-2, LrPAL-3, LrC4H-2, LrC3H, LrTYDC2, LrN4OMT, LrNNR, and LrCYP96T) revealed that seven genes, except LrN4OMT, were significantly expressed following exposure to wounding stress. Galantamine contents of calli after 3, 6, 12, 24, 48, 72, and 96 h of exposure were respectively 2.5, 2.5, 3.5, 3.5, 5.0, 5.0, and 8.5 times higher than that after 0 h of exposure. Furthermore, a total of 48 hydrophilic metabolites were detected in the 0 h exposed callus and 96 h exposed callus using GC-TOFMS. In particular, a strong positive correlation between galantamine and initial precursors, such as phenylalanine and tyrosine, was observed.

Development of a novel method for polar metabolite profiling by supercritical fluid chromatography/tandem mass spectrometry

Supercritical carbon dioxide (scCO2), the main fluid in the mobile phase for supercritical fluid chromatography (SFC), is non-polar. The majority of polar compounds are little soluble in scCO2, thereby rendering them poor candidates for achieving separation by carbon dioxide-based SFC. There is no reported method for the comprehensive analysis of hydrophilic metabolites by SFC with mobile phases comprising a high CO2 ratio. In this study, we investigated the effect of additives in the modifier for enabling the application of SFC to profile diverse polar compounds for metabolomics. Eleven types of columns were screened by using proteinogenic amino acids as the model compounds. The addition of water and acids (formic acid and trifluoroacetic acid (TFA)) to the modifier was also investigated to improve the solubility of the polar compounds and mitigate the unfavorable interaction between the stationary phase and the polar compounds. A significant improvement in the peak shapes of the amino acids was observed upon addition of TFA. The CO2/modifier ratio and TFA concentration in the mobile phases were investigated using the CROWNPAK CR-I (+) column, which showed the best performance during the column-screening. The CO2/methanol/water/TFA ratio of 70/27/3/0.15 (v/v/v/v) was determined as the optimized mobile phase composition. Furthermore, the applicability of the optimized analytical method to other polar compounds was examined; 100 cationic and amphoteric compounds with predicted logPow values that ranged from –5.9 to 1.7 could be simultaneously analyzed without derivatization. Anionic compounds such as organic acids, phosphates, and sugars were excluded from the target analytes. Most of the previously reported SFC methods for analyzing polar compounds employ a gradient elution and require the use of high modifier ratios at 40% or more. In the proposed method, the use of water and TFA enabled the rapid and simultaneous analysis under isocratic elution within 10 min, even with a high CO2 ratio of 70%. Additionally, a rat serum extract was analyzed using the optimized conditions, and 43 polar metabolites were successfully detected. This result demonstrates the applicability of the SFC/tandem mass spectrometry method to real samples.

A Metabolomics Workflow for Analyzing Complex Biological Samples Using a Combined Method of Untargeted and Target-List Based Approaches.

In the highly dynamic field of metabolomics, we have developed a method for the analysis of hydrophilic metabolites in various biological samples. Therefore, we used hydrophilic interaction chromatography (HILIC) for separation, combined with a high-resolution mass spectrometer (MS) with the aim of separating and analyzing a wide range of compounds. We used 41 reference standards with different chemical properties to develop an optimal chromatographic separation. MS analysis was performed with a set of pooled biological samples human cerebrospinal fluid (CSF), and human plasma. The raw data was processed in a first step with Compound Discoverer 3.1 (CD), a software tool for untargeted metabolomics with the aim to create a list of unknown compounds. In a second step, we combined the results obtained with our internally analyzed reference standard list to process the data along with the Lipid Data Analyzer 2.6 (LDA), a software tool for a targeted approach. In order to demonstrate the advantages of this combined target-list based and untargeted approach, we not only compared the relative standard deviation (%RSD) of the technical replicas of pooled plasma samples (n = 5) and pooled CSF samples (n = 3) with the results from CD, but also with XCMS Online, a well-known software tool for untargeted metabolomics studies. As a result of this study we could demonstrate with our HILIC-MS method that all standards could be either separated by chromatography, including isobaric leucine and isoleucine or with MS by different mass. We also showed that this combined approach benefits from improved precision compared to well-known metabolomics software tools such as CD and XCMS online. Within the pooled plasma samples processed by LDA 68% of the detected compounds had a %RSD of less than 25%, compared to CD and XCMS online (57% and 55%). The improvements of precision in the pooled CSF samples were even more pronounced, 83% had a %RSD of less than 25% compared to CD and XCMS online (28% and 8% compounds detected). Particularly for low concentration samples, this method showed a more precise peak area integration with its 3D algorithm and with the benefits of the LDAs graphical user interface for fast and easy manual curation of peak integration. The here-described method has the advantage that manual curation for larger batch measurements remains minimal due to the target list containing the information obtained by an untargeted approach.

GC-MS-Based Metabolomics for the Smut Fungus Ustilago maydis: A Comprehensive Method Optimization to Quantify Intracellular Metabolites.

Ustilago maydis, a smut fungus, is an appealing model in fundamental research and an upcoming cell factory for industrial biotechnology. The genome of U. maydis has been sequenced and some synthesis pathways were biochemically described; however, the operation of the cellular metabolic network is not well-characterized. Thus, we conducted a comprehensive study to optimize the sample preparation procedure for metabolomics of U. maydis using GC-MS/MS. Due to the unique characteristics of U. maydis cell culture, two quenching solutions, different washing steps, eight extraction methods, and three derivatization conditions have been examined. The optimal method was then applied for stable isotope-assisted quantification of low molecular weight hydrophilic metabolites while U. maydis utilized different carbon sources including sucrose, glucose, and fructose. This study is the first report on a methodology for absolute quantification of intracellular metabolites in U. maydis central carbon metabolism such as sugars, sugar phosphates, organic acids, amino acids, and nucleotides. For biotechnological use, this method is crucial to exploit the full production potential of this fungus and can also be used to study other fungi of the family Ustilaginaceae.

Abstract 2564: Integrated transcriptomic, proteomic, and metabolomic analyses of human and mouse T cell leukemia

Abstract Nuclear and mitochondrial crosstalk plays an important role in regulating diverse cellular functions. It is contributed partly by non-canonical signaling in these two key subcellular compartments. Disruption of this signaling network has been shown to associate with oncogenic transformation. Our lab has long-term interests in studying the molecular mechanisms of cellular transformation by the oncogenic lymphocyte-specific protein tyrosine kinase (Lck). Previous reports from our lab show novel roles of Lck in both nucleus and mitochondrion of human and mouse T leukemic cell lines that exhibit metabolic reprogramming. However, it remains largely unclear how dysregulated nuclear and mitochondrial crosstalk leads to altered cellular metabolism in Lck-transformed leukemic cells. The purpose of our study is to combine transcriptomic, proteomic, and metabolomic approaches to establish a link between altered nuclear gene expression, mitochondrial activity, and metabolic shift in Lck-transformed leukemic cells. For human T cell leukemia, we compared Jurkat T cells with its Lck-deficient derivative Jcam cell line. For mouse T cell leukemia, we compared EL4 cells that express normal levels of Lck and LSTRA cells that overexpress active Lck kinase. For additional verification, Jcam cells were reconstituted with wild-type Lck and EL4 cells were transfected with constitutively-active Lck mutant kinase. Total RNAs were subjected to transcriptomic analysis to identify genes significantly upregulated or downregulated in Lck-transformed cells. Tyrosine-phosphorylated proteins were enriched from Lck-transformed cells and identified by LC-MS/MS. Hydrophilic metabolites were extracted from whole cells and subjected to targeted metabolomic analysis using LC-MS/MS. Pathway analysis of our transcriptomic data revealed significant changes of gene expression involved in several pathways, including cell adhesion and glycolysis pathways. We verified several glycolytic genes downregulated in Lck-transformed cells. These targets were further confirmed by reduced levels of corresponding metabolites. Proteomic analysis identified a set of novel target proteins potentially phosphorylated by Lck. Cyclin-dependent kinase 1 (CDK1) is of particular interest because its phosphorylation status correlates with its activity in regulating electron transport chain functions within mitochondrion. Our data suggest a link between tyrosine-phosphorylated CDK1 and reduced mitochondrial respiration. In conclusion, integrated transcriptomic, proteomic, and metabolomic analyses enabled us to identify novel target genes regulated, proteins phosphorylated, and metabolites altered in Lck-transformed leukemic cells. Collectively, our data demonstrate a unique pattern of metabolic reprogramming both similar and distinct from the well-known Warburg effect in cancer cells. Citation Format: Ching-Yu Chu, Szu-Yuan Chen, Fu-Yu Chueh, Mei-Ling Cheng, Chao-Lan Yu. Integrated transcriptomic, proteomic, and metabolomic analyses of human and mouse T cell leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2564.

Integrated lipidomics and targeted metabolomics analyses reveal changes in flavor precursors in psoas major muscle of castrated lambs

Castration may decrease off-odors and improve meat flavor. Meat flavor is generated through complex chemical reactions that involve hydrophilic and hydrophobic flavor precursors. In this study, we investigated the flavor precursors in psoas major muscles of castrated and intact sheep using lipidomics and targeted metabolomics. Castration decreased testosterone levels and increased intramuscular fat content. Six hundred fourteen lipid molecules confirmed showed a separation between castrated and intact sheep based on principal component analysis. Fourteen lipid species and 224 lipid molecules increased in castrated sheep. Targeted metabolomics analysis showed that 18 hydrophilic metabolites were affected by castration; however, only hypoxanthine significantly increased in the castration group. Among 45 volatiles identified, 1-octen-3-ol and hexanal were significantly higher in castrated sheep. These results revealed that lipids, hydrophilic metabolites, and volatile compounds in lamb were affected by castration, which might be beneficial in lamb quality.

1876-P: Gut Microbial Fermentation of Polysaccharides Impacts Insulin Resistance in Humans

Recent studies have highlighted the role of gut microbiota in the pathogenesis of cardiometabolic diseases. In particular, microbially produced metabolites have been shown to affect the host metabolism, however, their impacts on metabolic diseases have not been fully elucidated. For instance, the findings from an obese mouse model have suggested that polysaccharide fermentation could serve as the additional energy sources, yet the effects on human pathology has not been reported. To address this question, we applied a multi-omics strategy, which integrated gut microbiome analyses with multi-platform metabolomic techniques. We sampled from 306 Japanese males and females with obesity (49.7%) and prediabetes (32.7%). Fecal microbiome was analyzed by 16S rRNA amplicon and metagenomic shot-gun sequencings, while fecal hydrophilic and lipid metabolites were measured using GC-MS and LC-MS-based platforms respectively, and were clustered by their co-expression profiles. We found that three out of 19 fecal hydrophilic clusters and three out of 86 lipid clusters were significantly associated with insulin resistance (IR) defined by HOMA-IR. Notably, the identified fecal hydrophilic clusters were classified as sugar derivatives such as monosaccharides and disaccharides. These metabolites were indeed increased in not only the fecal contents but also the plasma samples of IR group. In addition, microbes belonging to genera Dorea and Coprococcus, which are known to degrade polysaccharides, were abundant in the IR group, and were highly correlated with fecal sugar derivatives, while other microbes such as Alistipes showed negative correlation. Finally, we confirmed that the oral administration of a Dorea strain to HFD-fed mice exacerbated obesity and IR compared with Alistipes administration. Collectively, we report a novel mechanistic insight into the effects of gut microbes on metabolic diseases, where microbial fermentation of polysaccharides and its derivatives impact the host metabolism. Disclosure T. Takeuchi: None. Y. Nakanishi: None. K. Ikeda: None. H. Tsugawa: None. W. Suda: None. Y. Mizuno: None. N. Yamamichi: None. M. Arita: None. M. Hattori: None. N. Kubota: None. T. Kubota: None. T. Kadowaki: Research Support; Self; Astellas Pharma Inc., Daiichi Sankyo, Mitsubishi Tanabe Pharma Corporation, MSD Corporation, Novartis Pharma K.K., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited. Speaker’s Bureau; Self; Abbott, Astellas Pharma Inc., AstraZeneca K.K., Boehringer Ingelheim Pharmaceuticals, Inc., Cosmic Corporation, Daiichi Sankyo, Eli Lilly Japan K.K., FUJIFILM, Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Medscape Education, Medtronic, Mitsubishi Tanabe Pharma Corporation, MSD Corporation, NIPRO Medical Corporation, Novartis Pharma K.K., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi, Sanwa Kagaku Kenkyusho, Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. Other Relationship; Self; Asahi Mutual Life Insurance. S. Koyasu: None. H. Ohno: None.

Characterization of Postprandial Effects on CSF Metabolomics: A Pilot Study with Parallel Comparison to Plasma.

Cerebrospinal fluid (CSF) metabolites reflect biochemical diffusion/export from the brain and possibly serve as biomarkers related to brain disease severity, pathophysiology, and therapeutic efficacy/toxicity. Metabolomic studies using blood matrices have demonstrated interindividual and preanalytical variation of blood metabolites, whereas those of CSF metabolites remain unclear. In this study, we aimed to delineate the postprandial effects on CSF metabolites because fasting of patients with brain-related disorders is challenging. We collected pre- and postprandial (1.5, 3, and 6 h) plasma and CSF from nine healthy subjects. Using a mass-spectrometry-based global metabolomics approach, 150 and 130 hydrophilic metabolites and 263 and 340 lipids were detected in CSF and plasma, respectively. Principal component analysis of CSF hydrophilic metabolites and lipids primarily classified individual subjects at any time point, suggesting that the postprandial effects had a lower impact than interindividual variations on CSF metabolites. Individually, less than 10% of the CSF metabolites were putatively altered by postprandial effects (with either significant differences or over 2-fold changes, but not both) at any time point. Thus, global CSF metabolite levels are not directly associated with food intake, and except for several putatively altered CSF metabolites, postprandial effects are not a major concern when applying CSF metabolomics to screen biomarkers.

Identification of CYP1A1 Gene Polymorphism in Squamous Cell Carcinoma and Cervical Adenocarcinoma

BackgroundCervical cancer is the third most common cancer in women with risk factor of smoking, high parity, long term use of oralcontaception that are associated with chemical carcinogenesis. Chemical carcinogenesis require biotransfor-mation of lipophilicsubstrates to hydrophilic metabolites, therefore facilitating their secretion from the human body. Cytochrome P450 (CYP) is one ofgenes that have important role in this process. Benzo[α]pyrene and estrogen have a common biotransformation process which ismetabolized by CYP, particularly CYP1A1. The objectives to identify the frequency and distribution of CYP1A1 gene polymorphismin squamous cell carcinoma and adenocarcinoma of the cervix.MethodsThis is an analytical descriptive study with cross sectional approach. CYP1A1 gene polymorphism (3801T/C or Ile462Val) wasanalyzed using PCR-RFLP method followed by gel electrophoresis.ResultsCYP1A1 gene polymorphisms (3801TC) in squamous cell carcinoma were 50% heterozygote T/C, 36% wild-types T/T and 14%homozygote C/C. CYP1A1 gene polymorphisms (3801TC) in adenocarcinoma were 60% heterozygote T/C and 40% wild-types T/T.CYP1A1 gene polymorphisms (Ile462Val) in squamous cell carcinoma were 97.2% heterozygote Ile/Val, and 2.8% homozygoteVal/Val. CYP1A1 gene polymorphisms (Ile462Val) in adenocarcinoma were 100% heterozygote Ile/ValConclusionThe most common type of CYP1A1 gene polymorphism (3801TC and Ile462Val) in squamous cell carcinoma and adenocarcinomaof the cervix were heterozygote.

Challenges in Analysis of Hydrophilic Metabolites Using Chromatography Coupled with Mass Spectrometry

Hydrophilic metabolites play important roles in cellular energy metabolism, signal transduction, immunity. However, there are challenges in both identification and quantification of the hydrophilic metabolites due to their weak interactions with C18-reversed-phase liquid chromatography (RPLC), leading to poor retention of hydrophilic metabolites on the columns. Many strategies have been put forward to increase the retention behavior of hydrophilic metabolites in the RPLC system. Non-derivatization methods are mainly focused on the development of new chromatographic techniques with different separation mechanisms, such as capillary electrophoresis, ion-pairing RPLC etc. Derivatization methods improve the hydrophobicity of metabolites and can enhance the MS response. This review mainly focused on the illustration of challenges of LCMS in the analysis of hydrophilic metabolomics field, and summarized the non-derivatization and derivatization strategies, with the intention of providing multiple choices for analysis of hydrophilic metabolites.

Gas Chromatography-Mass Spectrometry-Based Metabolite Profiling for the Assessment of Freshness in Gilthead Sea Bream (Sparus aurata).

Gilthead sea bream (Sparus aurata) is one of the most important farmed Mediterranean fish species, and there is considerable interest for the development of suitable methods to assess its freshness. In the present work, gas chromatography–mass spectrometry-based metabolomics was employed to monitor the hydrophilic metabolites of sea bream during storage on ice for 19 days. Additionally, the quality changes were evaluated using two conventional methods: sensory evaluation according to European Union’s grading scheme and K-value, the most widely used chemical index of fish spoilage. With the application of chemometrics, the fish samples were successfully classified in the freshness categories, and a partial least squares regression model was built to predict K-value. A list of differential metabolites were found, which were distinguished according to their evolution profile as potential biomarkers of freshness and spoilage. Therefore, the results support the suitability of the proposed methodology to gain information on seafood quality.

ATP-BINDING CASSETTE TRANSPORTERS (ABC). NOMENCLATURE, STRUCTURE, MOLECULAR DIVERSITY, FUNCTION, CONTRIBUTION TO THE FUNCTIONING OF THE XENOBIOTICS TRANSFORMATION SYSTEM (А REWIEW)

ATP-binding cassette (ABC) transporters are membrane proteins responsible for removing various substrates from cells through cell membranes using the energy derived from ATP hydrolysis. The human genome codes for 48 ABC transporters, which are categorized into eight families: ABCA, ABCB, ABCC, ABCD, ABCE, ABCF, ABCG, ABCH. An ABC molecule consists of two nucleotide-binding domains (NBD) and two transmembrane domains (TMD) which transport substrates (NBD–TMD–NBD–TMD), or exists as a half-transporter consisting of one NBD and one TMD, which functions as a dimer. It is assumed that the ABC transport cycle is a four-stage one. The energy obtained in the hydrolysis of ATP is utilized to remove the substrate from the complex with the transporter molecule and restore it in its original state. In mammals, ABC were, apart from cancer cells, found in many tissues, such as the brain, adrenal glands, kidneys, lungs, testes, liver, placenta, intestines. ABC substrates encompass a wide range of compounds of both endo- and exogenous origin. Some ABC are involved in metabolizing xenobiotics, actively removing both lipophilic compounds that pass through the plasma membrane, and hydrophilic metabolites and conjugates formed in biotransformation phases I and II. A number of studies have demonstrated the interaction between the CYP3A4 enzyme from the P450 cytochrome group (biotransformation phase I) and the transporter АВСВ1. The ABCG2 transporter from the liver and intestines was found to actively export metabolites of biotransformation phase II.

An Analytical System for Single-Cell Metabolomics of Typical Mammalian Cells Based on Highly Sensitive Nano-Liquid Chromatography Tandem Mass Spectrometry.

The rapid development of next-generation sequencing techniques has enabled single-cell genomic and transcriptomic analyses, which have revealed the importance of heterogeneity in biological systems. However, analytical methods to accurately identify and quantify comprehensive metabolites from single mammalian cells with a typical diameter of 10–20 μm are still in the process of development. The aim of this study was to develop a single-cell metabolomic analytical system based on highly sensitive nano-liquid chromatography tandem mass spectrometry (nano-LC-MS/MS) with multiple reaction monitoring. A packed nano-LC column (3-μm particle-size pentafluorophenylpropyl Discovery HSF5 of dimensions 100 μm i.d.×180 mm) was prepared using a slurry technique. The optimized nano-LC-MS/MS method showed 3–132-fold (average value, 26-fold) greater sensitivity than semimicro-LC-MS/MS, and the detection limits for several hydrophilic metabolites, including amino acids and nucleic acid related metabolites were in the sub-fmol range. By combining live single-cell sampling and nano-LC-MS/MS, we successfully detected 18 relatively abundant hydrophilic metabolites (16 amino acids and 2 nucleic acid related metabolites) from single HeLa cells (n=22). Based on single-cell metabolic profiles, the 22 HeLa cells were classified into three distinct subclasses, suggesting differences in metabolic function in cultured HeLa cell populations. Our single-cell metabolomic analytical system represents a potentially useful tool for in-depth studies focused on cell metabolism and heterogeneity.

The dissolution and microbial degradation of mobile aromatic hydrocarbons from a Pintsch gas tar DNAPL source zone

Source zones containing tar, a dense non-aqueous phase liquid (DNAPL), can contaminate groundwater for centuries. A common occurrence of tar is at former Pintsch gas factories. Little is known about the composition and fate of contaminants dissolving from Pintsch gas tar DNAPL. In this study, we determined the composition and water-soluble characteristics of mobile aromatic hydrocarbons and their biodegradation metabolites in the DNAPL contaminated groundwater at a former Pintsch gas tar plant. We assessed the factors that determine the fate of observed groundwater contaminants. Measured values of density (1.03–1.06 kg/m3) and viscosity (18.6–39.4 cP) were found to be relatively low compared to common coal tars. Analysis showed that unlike common coal tars phenanthrene is the primary component rather than naphthalene. Moreover, it was found that Pintsch gas tar contains a relatively high amount of light molecular aromatic hydrocarbon compounds, such as benzene, toluene, ethylbenzene and xylenes (BTEX). Less commonly reported components, such as styrene, ethyltoluenes, di-ethylbenzene, 1,2,4,5-tetramethylbenzene, were also detected in water extracts from Pintsch gas tar. Moreover, 46 relatively hydrophilic metabolites were found within the tar samples. Metabolites present within the tar suggest biodegradation of mobile aromatic Pintsch gas tar compounds occurred near the DNAPL. Based on eleven detected suspect metabolites, a novel anaerobic biodegradation pathway is proposed for indene. Overall, our findings indicate that Pintsch gas tar has higher invasive and higher flux properties than most coal tars due to its relatively low density, low viscosity and, high content of water-soluble compounds. The partitioning of contaminants from multi-component DNAPL into the aqueous phase and re-dissolution of their slightly less hydrophobic metabolites back from the aqueous phase into the DNAPL is feasible and demonstrates the complexity of assessing degradation processes within a source zone.

Gametogenesis-Related Fluctuations in Ovothiol Levels in the Mantle of Mussels from Different Estuaries: Fighting Oxidative Stress for Spawning in Polluted Waters

Reactive oxygen species present a challenge for marine organisms releasing gametes into the water. Thiol-containing molecules protect cells against oxidative stress, and ovothiol (OSH), an antioxidant-reducing mercaptohistidine, has been described as especially relevant in the oocytes of marine invertebrates. Ovothiol synthase (ovoA), in charge of the first step in OSH synthesis, was sequenced in mussels, Mytilus galloprovincialis. Transcription levels of ovoA in mantle did not significantly change along the reproductive cycle. No alterations of ovoA transcription were observed after a laboratory copper (10 µg/L) exposure or in mussels captured in a highly polluted site. Conversely, the metabolomic analysis of the hydrophilic metabolite content in mantle clearly classified mussels according to their site of origin, especially at the most advanced stages of oogenesis. Quantification of OSH-A and -B and glutathione (GSH), revealed stable levels in mantle at early gametogenesis in the unpolluted sampling site, but a strong increase in female mantle previous to spawning in the polluted site. These increased concentrations under pollution suggest that OSH-A accumulates along oogenesis, independent of gene transcription regulation. The concerted accumulation of OSH-A and GSH suggests the building of a balanced cellular redox-system to scavenge ROS produced in the oocyte before and during fertilization.

Serum Tryptophan-Derived Quinolinate and Indole-3-Acetate Are Associated With Carotid Intima-Media Thickness and its Evolution in HIV-Infected Treated Adults.

BackgroundHIV-infected individuals undergoing effective antiretroviral therapy (ART) present an increased risk of atherosclerotic cardiovascular disease. We identified serum metabolites associated with carotid intima-media thickness (c-IMT) and its evolution.MethodsOne hundred forty-three hydrophilic serum metabolites were measured by ultraperformance liquid chromatography coupled with high-resolution mass spectrometry in 49 HIV+ ART+, 48 HIV+ ART-naïve and 50 HIV-negative, age-matched, never-smoking male triads. Metabolites differentially altered between groups (“features”) were defined as having a Benjamini-Hochberg-adjusted P value <.05 from a t test and >0.25 log2 absolute mean fold change in metabolite levels. c-IMT was measured across 12 sites at inclusion in all individuals and at the carotid artery (cca) after a median of 5.1 years in 32 HIV+ ART+ individuals. The difference in c-IMT (cross-sectional analysis) and slope of cca-IMT regression/progression per year (longitudinal analysis) for each log10 (area) increase in metabolite level were estimated with linear regression.ResultsCompared with HIV-, metabolite features of HIV+ ART+ were increased N6,N6,N6-trimethyl-L-lysine and decreased ferulate and 5-hydroxy-L-tryptophan, whereas features of HIV+ ART-naïve were increased malate, kynurenine, 2-oxoglutarate, and indole-3-acetate and decreased succinate and 5-hydroxy-L-tryptophan. In HIV+ ART+ individuals, quinolinate and/or indole-3-acetate were positively associated with c-IMT (P < .03), cca-IMT (P < .03), and cca-IMT progression (P < .008). These associations were not observed in HIV+ ART-naïve or HIV-negative individuals. In HIV+ ART+ individuals, the metabolites xanthosine and uridine, from nucleotide metabolism, and g-butyrobetaine, from lysine/dietary choline degradation, were also positively or negatively associated with c-IMT and/or cca-IMT (all P < .01), but not its evolution.ConclusionsIn these highly selected HIV-positive ART-controlled males, 2 novel metabolites derived from tryptophan catabolism, indole-3-acetate and quinolinate, were associated with c-IMT and its progression.