Integrative Molecular Phenotyping
INTEGRATIVE MOLECULAR
PHENOTYPING
WHEELOCK LABORATORY
DEPARTMENT OF MEDICAL
BIOCHEMISTRY AND BIOPHYSICS
WHEELOCK LABORATORY
DEPARTMENT OF MEDICAL
BIOCHEMISTRY AND BIOPHYSICS
WHEELOCK LABORATORY
DEPARTMENT OF MEDICAL
BIOCHEMISTRY AND BIOPHYSICS
WHEELOCK LABORATORY
DEPARTMENT OF MEDICAL
BIOCHEMISTRY AND BIOPHYSICS
WHEELOCK LABORATORY
DEPARTMENT OF MEDICAL
BIOCHEMISTRY AND BIOPHYSICS
WHEELOCK LABORATORY

PubMed

Metabolic Dysregulation after Neutron Exposures Expected from an Improvised Nuclear Device.

Sun, 07/05/2017 - 18:32
Metabolic Dysregulation after Neutron Exposures Expected from an Improvised Nuclear Device. Radiat Res. 2017 May 05;: Authors: Laiakis EC, Wang YW, Young EF, Harken AD, Xu Y, Smilenov L, Garty GY, Brenner DJ, Fornace AJ Abstract The increased threat of terrorism across the globe has raised fears that certain groups will acquire and use radioactive materials to inflict maximum damage. In the event that an improvised nuclear device (IND) is detonated, a potentially large population of victims will require assessment for radiation exposure. While photons will contribute to a major portion of the dose, neutrons may be responsible for the severity of the biologic effects and cellular responses. We investigated differences in response between these two radiation types by using metabolomics and lipidomics to identify biomarkers in urine and blood of wild-type C57BL/6 male mice. Identification of metabolites was based on a 1 Gy dose of radiation. Compared to X rays, a neutron spectrum similar to that encountered in Hiroshima at 1-1.5 km from the epicenter induced a severe metabolic dysregulation, with perturbations in amino acid metabolism and fatty acid β-oxidation being the predominant ones. Urinary metabolites were able to discriminate between neutron and X rays on day 1 as well as day 7 postirradiation, while serum markers showed such discrimination only on day 1. Free fatty acids from omega-6 and omega-3 pathways were also decreased with 1 Gy of neutrons, implicating cell membrane dysfunction and impaired phospholipid metabolism, which should otherwise lead to release of those molecules in circulation. While a precise relative biological effectiveness value could not be calculated from this study, the results are consistent with other published studies showing higher levels of damage from neutrons, demonstrated here by increased metabolic dysregulation. Metabolomics can therefore aid in identifying global perturbations in blood and urine, and effectively distinguishing between neutron and photon exposures. PMID: 28475424 [PubMed - as supplied by publisher]

Identification of differential metabolic characteristics between tumor and normal tissue from colorectal cancer patients by gas chromatography-mass spectrometry.

Sun, 07/05/2017 - 18:32
Identification of differential metabolic characteristics between tumor and normal tissue from colorectal cancer patients by gas chromatography-mass spectrometry. Biomed Chromatogr. 2017 May 05;: Authors: Ning W, Li H, Meng F, Cheng J, Song X, Zhang G, Wang W, Wu S, Fang J, Ma K, Yang J, Pei D, Dong F Abstract Colorectal cancer (CRC) is one of the most common human malignancies and encompasses cancers of the colon and rectum. Although the gold-standard colonoscopy screening method is effective in detecting CRC, this method is invasive and can result in severe complications for patients. The purpose of this study was to determine differences in metabolites between CRC and matched adjacent non-tumor tissues from CRC patients, to identify potential biomarkers that may be informative and developed screening methods. Metabolomic analysis was performed on clinically localized CRC tissue and matched adjacent non-tumor tissue from twenty CRC patients. Unsupervised analysis, supervised analysis, univariate analysis, and pathway analysis were used to identify potential metabolic biomarkers of CRC. The level of twenty-five metabolites in CRC tissues were significantly altered compared to the matched adjacent non-tumor tissues. Four metabolites (lactic acid, alanine, phosphate, and aspartic acid) demonstrated good area under the curve (AUC) of Receiver- Operator Characteristic (ROC) with acceptable sensitivities and specificities, indicating their potential as important biomarkers for CRC. Alterations of amino acid metabolism and enhanced glycolysis may be major factors in the development and progression of colorectal cancer. Lactic acid, alanine, phosphate, and aspartic acid could be effective diagnostic indicators for CRC. PMID: 28475217 [PubMed - as supplied by publisher]

Metabolomic profiling and biochemical evaluation of the follicular fluid of endometriosis patients.

Sun, 07/05/2017 - 18:32
Metabolomic profiling and biochemical evaluation of the follicular fluid of endometriosis patients. Mol Biosyst. 2017 May 05;: Authors: Marianna S, Alessia P, Susan C, Francesca C, Angela S, Francesca C, Antonella N, Patrizia I, Nicola C, Emilio C Abstract Diseases are complex systems that can be studied through the integration of data derived from different disciplines to obtain a global and reliable picture of the biological phenomenon under investigation. Based on the recent observations that the metabolomics profiling of follicular fluids reflects the ovarian microenvironment of women and that endometriosis represents an example of complex diseases, clearly diagnosed by laparoscopy, we thought that the follicular fluids of endometriosis patients can represent a study model to evaluate the possibility of integrating data obtained by different approaches. Hence, the aim of this work was to analyze and integrate different clinical chemistry parameters with specific reference to the metabolic profile, inflammatory state and cell damage by a (1)H-NMR approach and biochemical analysis in the follicular fluids of women with different stages of endometriosis (I-II and III-IV) subjected to the In Vitro Fertilization (IVF) cycle. Our analysis evidenced that in the follicular fluids of endometriosis patients the levels of phospholipids, lactate, insulin, PTX3, CXCL8, CXCL10, CCL11 and VEGF were higher whereas those of some fatty acids, lysine, choline, glucose, aspartate, alanine, leucine, valine, proline, phosphocholine, total LDH as well its LDH-3 isoform were lower in comparison to the control group. The levels of LDHB, PTX3 and insulin receptor were also confirmed by RT-PCR applied on cumulus cells surrounding oocytes retrieved from the patients. The reduced oocyte quality observed in patients with endometriosis can be certainly correlated to the different levels of these molecules. These data represent how the integration of different experimental approaches may be useful for understanding the underlying mechanisms of a complex disease and can lead to a better clinical management of endometriosis. PMID: 28475193 [PubMed - as supplied by publisher]

LILY-lipidome isotope labeling of yeast: in vivo synthesis of (13)C labeled reference lipids for quantification by mass spectrometry.

Sun, 07/05/2017 - 18:32
LILY-lipidome isotope labeling of yeast: in vivo synthesis of (13)C labeled reference lipids for quantification by mass spectrometry. Analyst. 2017 May 05;: Authors: Rampler E, Coman C, Hermann G, Sickmann A, Ahrends R, Koellensperger G Abstract Quantification is an essential task in comprehensive lipidomics studies challenged by the high number of lipids, their chemical diversity and their dynamic range of the lipidome. In this work, we introduce lipidome isotope labeling of yeast (LILY) in order to produce (non-radioactive) isotopically labeled eukaryotic lipid standards in yeast for normalization and quantification in mass spectrometric assays. More specifically, LILY is a fast and efficient in vivo labeling strategy in Pichia pastoris for the production of (13)C labeled lipid library further paving the way to comprehensive compound-specific internal standardization in quantitative mass spectrometry based assays. More than 200 lipid species (from PA, PC, PE, PG, PI, PS, LysoGP, CL, DAG, TAG, DMPE, Cer, HexCer, IPC, MIPC) were obtained from yeast extracts with an excellent (13)C enrichment >99.5%, as determined by complementary high resolution mass spectrometry based shotgun and high resolution LC-MS/MS analysis. In a first proof of principle study we tested the relative and absolute quantification capabilities of the (13)C enriched lipids obtained by LILY using a parallel reaction monitoring based LC-MS approach. In relative quantification it could be shown that compound specific internal standardization was essential for the accuracy extending the linear dynamic range to four orders of magnitude. Excellent analytical figures of merit were observed for absolute quantification for a selected panel of 5 investigated glycerophospholipids (e.g. LOQs around 5 fmol absolute; typical concentrations ranging between 1 to 10 nmol per 10(8) yeast cell starting material; RSDs <10% (N = 4)). PMID: 28475182 [PubMed - as supplied by publisher]

The Use of "Omics" in Lactation Research in Dairy Cows.

Sun, 07/05/2017 - 18:32
The Use of "Omics" in Lactation Research in Dairy Cows. Int J Mol Sci. 2017 May 05;18(5): Authors: Li S, Wang Q, Lin X, Jin X, Liu L, Wang C, Chen Q, Liu J, Liu H Abstract "Omics" is the application of genomics, transcriptomics, proteomics, and metabolomics in biological research. Over the years, tremendous amounts of biological information has been gathered regarding the changes in gene, mRNA and protein expressions as well as metabolites in different physiological conditions and regulations, which has greatly advanced our understanding of the regulation of many physiological and pathophysiological processes. The aim of this review is to comprehensively describe the advances in our knowledge regarding lactation mainly in dairy cows that were obtained from the "omics" studies. The "omics" technologies have continuously been preferred as the technical tools in lactation research aiming to develop new nutritional, genetic, and management strategies to improve milk production and milk quality in dairy cows. PMID: 28475129 [PubMed - in process]

Cowpea (Vigna unguiculata L. Walp.) Metabolomics: Osmoprotection as a Physiological Strategy for Drought Stress Resistance and Improved Yield.

Sun, 07/05/2017 - 18:32
Related Articles Cowpea (Vigna unguiculata L. Walp.) Metabolomics: Osmoprotection as a Physiological Strategy for Drought Stress Resistance and Improved Yield. Front Plant Sci. 2017;8:586 Authors: Goufo P, Moutinho-Pereira JM, Jorge TF, Correia CM, Oliveira MR, Rosa EAS, António C, Trindade H Abstract Plants usually tolerate drought by producing organic solutes, which can either act as compatible osmolytes for maintaining turgor, or radical scavengers for protecting cellular functions. However, these two properties of organic solutes are often indistinguishable during stress progression. This study looked at individualizing properties of osmotic adjustment vs. osmoprotection in plants, using cowpea as the model species. Two cultivars were grown in well-watered soil, drought conditions, or drought followed by rewatering through fruit formation. Osmoadaptation was investigated in leaves and roots using photosynthetic traits, water homoeostasis, inorganic ions, and primary and secondary metabolites. Multifactorial analyses indicated allocation of high quantities of amino acids, sugars, and proanthocyanidins into roots, presumably linked to their role in growth and initial stress perception. Physiological and metabolic changes developed in parallel and drought/recovery responses showed a progressive acclimation of the cowpea plant to stress. Of the 88 metabolites studied, proline, galactinol, and a quercetin derivative responded the most to drought as highlighted by multivariate analyses, and their correlations with yield indicated beneficial effects. These metabolites accumulated differently in roots, but similarly in leaves, suggesting a more conservative strategy to cope with drought in the aerial parts. Changes in these compounds roughly reflected energy investment in protective mechanisms, although the ability of plants to adjust osmotically through inorganic ions uptake could not be discounted. PMID: 28473840 [PubMed - in process]

Metabolic Profiles in Cell Lines Infected with Classical Swine Fever Virus.

Sun, 07/05/2017 - 18:32
Related Articles Metabolic Profiles in Cell Lines Infected with Classical Swine Fever Virus. Front Microbiol. 2017;8:691 Authors: Gou H, Zhao M, Yuan J, Xu H, Ding H, Chen J Abstract Viruses require energy and biosynthetic precursors from host cells for replication. An understanding of the metabolic interplay between classical swine fever virus (CSFV) and host cells is important for exploring the complex pathological mechanisms of classical swine fever (CSF). In the current study, and for the first time, we utilized an approach involving gas chromatography coupled with mass spectrometry (GC-MS) to examine the metabolic profiles within PK-15 and 3D4/2 cells infected with CSFV. The differential metabolites of PK-15 cells caused by CSFV infection mainly included the decreased levels of glucose 6-phosphate [fold change (FC) = -1.94)] and glyceraldehyde-3-phosphate (FC = -1.83) during glycolysis, ribulose 5-phosphate (FC = -1.51) in the pentose phosphate pathway, guanosine (FC = -1.24) and inosine (FC = -1.16) during purine biosynthesis, but the increased levels of 2-ketoisovaleric acid (FC = 0.63) during the citrate cycle, and ornithine (FC = 0.56) and proline (FC = 0.62) during arginine and proline metabolism. However, metabolite changes caused by CSFV infection in 3D4/2 cells included the reduced glyceraldehyde-3-phosphate (FC = -0.77) and pyruvic acid (FC = -1.42) during glycolysis, 2-ketoglutaric acid (FC = -1.52) in the citrate cycle, and the elevated cytosine (FC = 2.15) during pyrimidine metabolism. Our data showed that CSFV might rebuild cellular metabolic programs, thus aiding viral replication. These findings may be important in developing targets for new biomarkers for the diagnosis and identification of enzyme inhibitors or metabolites as antiviral drugs, or screening viral gene products as vaccines. PMID: 28473819 [PubMed - in process]

Metabolic profiling identifies trehalose as an abundant and diurnally fluctuating metabolite in the microalga Ostreococcus tauri.

Sun, 07/05/2017 - 18:32
Related Articles Metabolic profiling identifies trehalose as an abundant and diurnally fluctuating metabolite in the microalga Ostreococcus tauri. Metabolomics. 2017;13(6):68 Authors: Hirth M, Liverani S, Mahlow S, Bouget FY, Pohnert G, Sasso S Abstract INTRODUCTION: The picoeukaryotic alga Ostreococcus tauri (Chlorophyta) belongs to the widespread group of marine prasinophytes. Despite its ecological importance, little is known about the metabolism of this alga. OBJECTIVES: In this work, changes in the metabolome were quantified when O. tauri was grown under alternating cycles of 12 h light and 12 h darkness. METHODS: Algal metabolism was analyzed by gas chromatography-mass spectrometry. Using fluorescence-activated cell sorting, the bacteria associated with O. tauri were depleted to below 0.1% of total cells at the time of metabolic profiling. RESULTS: Of 111 metabolites quantified over light-dark cycles, 20 (18%) showed clear diurnal variations. The strongest fluctuations were found for trehalose. With an intracellular concentration of 1.6 mM in the dark, this disaccharide was six times more abundant at night than during the day. This fluctuation pattern of trehalose may be a consequence of starch degradation or of the synchronized cell cycle. On the other hand, maltose (and also sucrose) was below the detection limit (~10 μM). Accumulation of glycine in the light is in agreement with the presence of a classical glycolate pathway of photorespiration. We also provide evidence for the presence of fatty acid methyl and ethyl esters in O. tauri. CONCLUSIONS: This study shows how the metabolism of O. tauri adapts to day and night and gives new insights into the configuration of the carbon metabolism. In addition, several less common metabolites were identified. PMID: 28473745 [PubMed - in process]

Untargeted metabolomics reveals a mild impact of remote ischemic conditioning on the plasma metabolome and α-hydroxybutyrate as a possible cardioprotective factor and biomarker of tissue ischemia.

Sun, 07/05/2017 - 18:32
Related Articles Untargeted metabolomics reveals a mild impact of remote ischemic conditioning on the plasma metabolome and α-hydroxybutyrate as a possible cardioprotective factor and biomarker of tissue ischemia. Metabolomics. 2017;13(6):67 Authors: Laursen MR, Hansen J, Elkjær C, Stavnager N, Nielsen CB, Pryds K, Johnsen J, Nielsen JM, Bøtker HE, Johannsen M Abstract INTRODUCTION: Remote ischemic conditioning (RIC) is a maneuver by which short non-lethal ischemic events are applied on distant organs or limbs to reduce ischemia and reperfusion injuries caused by e.g. myocardial infarct. Although intensively investigated, the specific mechanism of this protective phenomenon remains incompletely understood and in particular, knowledge on the role of small metabolites is scarce. OBJECTIVES: In this study, we aimed to study perturbations in the plasma metabolome following RIC and gain insight into metabolic changes by the intervention as well as to identify potential novel cardio-protective metabolites. METHODS: Blood plasma samples from ten healthy males were collected prior to and after RIC and tested for bioactivity in a HL-1 based cellular model of ischemia-reperfusion damage. Following this, the plasma was analyzed using untargeted LC-qTOF-MS and regulated metabolites were identified using univariate and multivariate statistical analysis. Results were finally verified in a second plasma study from the same group of volunteers and by testing a metabolite ester in the HL-1 cell model. RESULTS: The analysis revealed a moderate impact on the plasma metabolome following RIC. One metabolite, α-hydroxybutyrate (AHB) however, stood out as highly significantly upregulated after RIC. AHB might be a novel and more sensitive plasma-biomarker of transient tissue ischemia than lactate. Importantly, it was also found that a cell permeable AHB precursor protects cardiomyocytes from ischemia-reperfusion damage. CONCLUSION: Untargeted metabolomics analysis of plasma following RIC has led to insight into metabolism during RIC and revealed a possible novel metabolite of relevance to ischemic-reperfusion damage. PMID: 28473744 [PubMed - in process]

The effects of thawing on the plasma metabolome: evaluating differences between thawed plasma and multi-organ samples.

Sun, 07/05/2017 - 18:32
Related Articles The effects of thawing on the plasma metabolome: evaluating differences between thawed plasma and multi-organ samples. Metabolomics. 2017;13(6):66 Authors: Torell F, Bennett K, Rännar S, Lundstedt-Enkel K, Lundstedt T, Trygg J Abstract INTRODUCTION: Post-collection handling, storage and transportation can affect the quality of blood samples. Pre-analytical biases can easily be introduced and can jeopardize accurate profiling of the plasma metabolome. Consequently, a mouse study must be carefully planned in order to avoid any kind of bias that can be introduced, in order not to compromise the outcome of the study. The storage and shipment of the samples should be made in such a way that the freeze-thaw cycles are kept to a minimum. In order to keep the latent effects on the stability of the blood metabolome to a minimum it is essential to study the effect that the post-collection and pre-analytical error have on the metabolome. OBJECTIVES: The aim of this study was to investigate the effects of thawing on the metabolic profiles of different sample types. METHODS: In the present study, a metabolomics approach was utilized to obtain a thawing profile of plasma samples obtained on three different days of experiment. The plasma samples were collected from the tail on day 1 and 3, while retro-orbital sampling was used on day 5. The samples were analysed using gas chromatography time-of-flight mass spectrometry (GC TOF-MS). RESULTS: The thawed plasma samples were found to be characterized by higher levels of amino acids, fatty acids, glycerol metabolites and purine and pyrimidine metabolites as a result of protein degradation, cell degradation and increased phospholipase activity. The consensus profile was thereafter compared to the previously published study comparing thawing profiles of tissue samples from gut, kidney, liver, muscle and pancreas. CONCLUSIONS: The comparison between thawed organ samples and thawed plasma samples indicate that the organ samples are more sensitive to thawing, however thawing still affected all investigated sample types. PMID: 28473743 [PubMed - in process]

Omics Fusion - A Platform for Integrative Analysis of Omics Data.

Sun, 07/05/2017 - 18:32
Related Articles Omics Fusion - A Platform for Integrative Analysis of Omics Data. J Integr Bioinform. 2016 Dec 18;13(4):296 Authors: Brink BG, Seidel A, Kleinbölting N, Nattkemper TW, Albaum SP Abstract We present Omics Fusion, a new web-based platform for integrative analysis of omics data. Omics Fusion provides a collection of new and established tools and visualization methods to support researchers in exploring omics data, validating results or understanding how to adjust experiments in order to make new discoveries. It is easily extendible and new visualization methods are added continuously. It is available for free under: https://fusion.cebitec.uni-bielefeld.de/. PMID: 28187412 [PubMed - indexed for MEDLINE]

Comprehensive metabolomics identified lipid peroxidation as a prominent feature in human plasma of patients with coronary heart diseases.

Fri, 05/05/2017 - 14:27
Related Articles Comprehensive metabolomics identified lipid peroxidation as a prominent feature in human plasma of patients with coronary heart diseases. Redox Biol. 2017 Apr 26;12:899-907 Authors: Lu J, Chen B, Chen T, Guo S, Xue X, Chen Q, Zhao M, Xia L, Zhu Z, Zheng L, Yin H Abstract Coronary heart disease (CHD) is a complex human disease associated with inflammation and oxidative stress. The underlying mechanisms and diagnostic biomarkers for the different types of CHD remain poorly defined. Metabolomics has been increasingly recognized as an enabling technique with the potential to identify key metabolomic features in an attempt to understand the pathophysiology and differentiate different stages of CHD. We performed comprehensive metabolomic analysis in human plasma from 28 human subjects with stable angina (SA), myocardial infarction (MI), and healthy control (HC). Subsequent analysis demonstrated a uniquely altered metabolic profile in these CHD: a total of 18, 37 and 36 differential metabolites were identified to distinguish SA from HC, MI from SA, and MI from HC groups respectively. Among these metabolites, glycerophospholipid (GPL) metabolism emerged as the most significantly disturbed pathway. Next, we used a targeted metabolomic approach to systematically analyze GPL, oxidized phospholipid (oxPL), and downstream metabolites derived from polyunsaturated fatty acids (PUFAs), such as arachidonic acid and linoleic acid. Surprisingly, lipids associated with lipid peroxidation (LPO) pathways including oxidized PL and isoprostanes, isomers of prostaglandins, were significantly elevated in plasma of MI patients comparing to HC and SA, consistent with the notion that oxidative stress-induced LPO is a prominent feature in CHD. Our studies using the state-of-the-art metabolomics help to understand the underlying biological mechanisms involved in the pathogenesis of CHD; LPO metabolites may serve as potential biomarkers to differentiation MI from SA and HC. PMID: 28472752 [PubMed - as supplied by publisher]

Saccharin induced liver inflammation in mice by altering the gut microbiota and its metabolic functions.

Fri, 05/05/2017 - 14:27
Related Articles Saccharin induced liver inflammation in mice by altering the gut microbiota and its metabolic functions. Food Chem Toxicol. 2017 May 01;: Authors: Bian X, Tu P, Chi L, Gao B, Ru H, Lu K Abstract Maintaining the balance of the gut microbiota and its metabolic functions is vital for human health, however, this balance can be disrupted by various external factors including food additives. A range of food and beverages are sweetened by saccharin, which is generally considered to be safe despite controversial debates. However, recent studies indicated that saccharin perturbed the gut microbiota. Inflammation is frequently associated with disruptions of the gut microbiota. The aim of this study is to investigate the relationship between host inflammation and perturbed gut microbiome by saccharin. C57BL/6J male mice were treated with saccharin in drinking water for six months. Q-PCR was used to detect inflammatory markers in mouse liver, while 16S rRNA gene sequencing and metabolomics were used to reveal changes of the gut microbiota and its metabolomic profiles. Elevated expression of pro-inflammatory iNOS and TNF-α in liver indicated that saccharin induced inflammation in mice. The altered gut bacterial genera, enriched orthologs of pathogen-associated molecular patterns, such as LPS and bacterial toxins, in concert with increased pro-inflammatory metabolites suggested that the saccharin-induced liver inflammation could be associated with the perturbation of the gut microbiota and its metabolic functions. PMID: 28472674 [PubMed - as supplied by publisher]

Oxidative profiling of the failing right heart in rats with pulmonary hypertension.

Fri, 05/05/2017 - 14:27
Related Articles Oxidative profiling of the failing right heart in rats with pulmonary hypertension. PLoS One. 2017;12(5):e0176887 Authors: Wang X, Shults NV, Suzuki YJ Abstract Right heart failure is the major cause of death among patients with pulmonary arterial hypertension (PAH). Understanding the biology of the right ventricle (RV) should help developing new therapeutic strategies. Rats subjected to the injection of Sugen5416 (an inhibitors of vascular endothelial growth factor receptor) plus the ovalbumin immunization had increased pulmonary arterial pressure and severe vascular remodeling. RVs of these rats were hypertrophied and had severe cardiac fibrosis. No apoptosis was, however, detected. Metabolomics analysis revealed that oxidized glutathione, xanthine and uric acid had increased in PAH RVs, suggesting the production of reactive oxygen species by xanthine oxidase. PAH RVs were also found to have a 30-fold lower level of α-tocopherol nicotinate, consistent with oxidative stress decreasing antioxidants and also demonstrating for the first time that the nicotinate ester of vitamin E is endogenously expressed. Oxidative/nitrosative protein modifications including S-glutathionylation, S-nitrosylation and nitrotyrosine formation, but not protein carbonylation, were found to be increased in RVs of rats with PAH. Mass spectrometry identified that S-nitrosylated proteins include heat shock protein 90 and sarcoplasmic reticulum Ca2+-ATPase. These results demonstrate that RV failure is associated with the promotion of specific oxidative and nitrosative stress. PMID: 28472095 [PubMed - in process]

Metabolite Spectral Accuracy on Orbitraps.

Fri, 05/05/2017 - 14:27
Related Articles Metabolite Spectral Accuracy on Orbitraps. Anal Chem. 2017 May 04;: Authors: Su X, Lu W, Rabinowitz JD Abstract Orbitraps are high-resolution ion-trap mass spectrometers that are widely used in metabolomics. While the mass accuracy and resolving power of orbitraps have been extensively documented, their spectral accuracy-i.e. accuracy in measuring the abundances of isotopic peaks-remains less studied. In analyzing spectra of unlabeled metabolites, we discovered a systematic under representation of heavier natural isotopic species, especially for high molecular weight metabolites (~20% underestimation of [M+1]/[M+0] ratio at m/z 600). We hypothesize that these discrepancies arise for metabolites far from lower limit of the mass scan range, due to the weaker containment in the C-trap that results in suboptimal trajectories inside the Orbitrap analyzer. Consistent with this, spectral fidelity was restored by dividing the mass scan range (initially 75 m/z to 1000 m/z) into two scan events, one for lower molecular weight and the other for higher molecular weight metabolites. Having thus obtained accurate mass spectra at high resolution, we found that natural isotope correction for high-resolution labeling data requires more sophisticated algorithms than typically employed: the correction algorithm must take into account whether isotopologues with the same nominal mass are resolved. We present an algorithm and associated open-source code, named AccuCor, for this purpose. Together, these improvements in instrument parameters and natural isotope correction enable more accurate measurement of metabolite labeling and thus metabolic flux. PMID: 28471646 [PubMed - as supplied by publisher]

Hydroxyeicosapentaenoic Acids and Epoxyeicosatetraenoic Acids Attenuate Early Occurrence of Nonalcoholic Fatty Liver Disease.

Fri, 05/05/2017 - 14:27
Related Articles Hydroxyeicosapentaenoic Acids and Epoxyeicosatetraenoic Acids Attenuate Early Occurrence of Nonalcoholic Fatty Liver Disease. Br J Pharmacol. 2017 May 04;: Authors: Wang C, Liu W, Yao L, Zhang X, Zhang X, Ye C, Jiang H, He J, Zhu Y, Ai D Abstract BACKGROUND AND PURPOSE: The ω-3 polyunsaturated fatty acids (PUFAs) mediate protective effects on several metabolic disorders. However, the functions of their metabolites in the early stage of nonalcoholic fatty liver disease (NAFLD) are largely unknown. EXPERIMENTAL APPROACH: Mice were fed a control diet, high-fat diet (HFD) or ω-3 PUFA-enriched HFD (ω3HFD) for 4 days and phenotypes were analyzed. LC-MS/MS was used to determine the eicosanoid profiles. Primary hepatocytes and peritoneal macrophages were used for the mechanism study. KEY RESULTS: In short-term HFD-fed mice, the significantly induced lipid accumulation in liver was reversed by ω-3 PUFA supplementation. Metabolomics showed the plasma content of hydroxyeicosapentaenoic acids (HEPEs) and epoxyeicosatetraenoic acids (EEQs) was reduced by a short-term HFD and markedly increased by the ω3HFD. However, HEPE/EEQ treatment had no direct protective effect on hepatocytes. ω3HFD also significantly attenuated HFD-induced adipose tissue inflammation. Furthermore, the expression of proinflammatory cytokines and activation of JNK pathway induced by palmitate were suppressed by HEPEs and EEQs in macrophages. 17,18-EEQ, 5-HEPE and 9-HEPE were identified as the efficient components among these metabolites, as evidenced by their greater suppression of the palmitate-induced expression of inflammatory factors, chemotaxis and JNK activation as compared with other metabolites in macrophages. A mixture of 17,18-EEQ, 5-HEPE and 9-HEPE significantly ameliorated the short-term HFD-induced accumulation of macrophages in adipose tissue and hepatic steatosis. CONCLUSION AND IMPLICATIONS: 17,18-EEQ, 5-HEPE and 9-HEPE may be potential approaches to prevent NAFLD in the early stage by inhibiting the inflammatory response in adipose tissue macrophages via JNK signaling. PMID: 28471490 [PubMed - as supplied by publisher]

Metabolite Profiling of Mammalian Cell Culture Processes to Evaluate Cellular Viability.

Fri, 05/05/2017 - 14:27
Related Articles Metabolite Profiling of Mammalian Cell Culture Processes to Evaluate Cellular Viability. Methods Mol Biol. 2017;1601:137-152 Authors: Evie IM, Dickson AJ, Elvin M Abstract Metabolite profiling allows for the identification of metabolites that become limiting during cell culture and/or for finding bottlenecks in metabolic pathways that limit culture growth and proliferation. Here we describe one protocol with two different sampling methodologies for GC-MS-based metabolite profiling. We also highlight an example of the types of datasets that are attainable and how such datasets can be evaluated to identify factors related to cell viability. We also demonstrate, via the same methodology, the accurate quantification of a number of metabolites of interest. PMID: 28470524 [PubMed - in process]

Synthesis of cyclooxygenase metabolites of 8,9-epoxyeicosatrienoic acid (EET): 11- and 15-hydroxy 8,9-EETs.

Fri, 05/05/2017 - 14:27
Related Articles Synthesis of cyclooxygenase metabolites of 8,9-epoxyeicosatrienoic acid (EET): 11- and 15-hydroxy 8,9-EETs. Org Biomol Chem. 2017 May 04;: Authors: Barnych B, Rand AA, Cajka T, Lee KSS, Hammock BD Abstract COX metabolites of 8,9-EET, previously observed as potent mitogenic lipid mediators, were synthesized for the first time by using two synthetic approaches. These synthetic materials allow for structural confirmation of COX metabolites of 8,9-EET and further study of their biological roles. PMID: 28470279 [PubMed - as supplied by publisher]

Metabolomics approach reveals annual metabolic variation in roots of Cyathula officinalis Kuan based on gas chromatography-mass spectrum.

Fri, 05/05/2017 - 14:27
Related Articles Metabolomics approach reveals annual metabolic variation in roots of Cyathula officinalis Kuan based on gas chromatography-mass spectrum. Chin Med. 2017;12:12 Authors: Tong K, Li ZL, Sun X, Yan S, Jiang MJ, Deng MS, Chen J, Li JW, Tian ML Abstract BACKGROUND: Herbal quality is strongly influenced by harvest time. It is therefore one of crucial factors that should be well respected by herbal producers when optimizing cultivation techniques, so that to obtain herbal products of high quality. In this work, we paid attention on one of common used Chinese herbals, Cyathula officinalis Kuan. According to previous studies, its quality may be related with growth years because of the variation of several main bioactive components in different growth years. However, information about the whole chemical composition is still scarce, which may jointly determine the herbal quality. METHODS: Cyathula officinalis samples were collected in 1-4 growth years after sowing. To obtain a global insight on chemical profile of herbs, we applied a metabolomics approach based on gas chromatography-mass spectrum. Analysis of variance, principal component analysis, partial least squares discriminant analysis and hierarchical cluster analysis were combined to explore the significant difference in different growth years. RESULTS: 166 metabolites were identified by using gas chromatography-mass spectrum method. 63 metabolites showed significant change in different growth years in terms of analysis of variance. Those metabolites then were grouped into 4 classes by hierarchical cluster analysis, characterizing the samples of different growth ages. Samples harvested in the earliest years (1-2) were obviously differ with the latest years (3-4) as reported by principal component analysis. Further, partial least squares discriminant analysis revealed the detail difference in each growth year. Gluconic acid, xylitol, glutaric acid, pipecolinic acid, ribonic acid, mannose, oxalic acid, digalacturonic acid, lactic acid, 2-deoxyerythritol, acetol, 3-hydroxybutyric acid, citramalic acid, N-carbamylglutamate, and cellobiose are the main 15 discrimination metabolites between different growth years. CONCLUSION: Harvest time should be well considered when producing C. officinalis. In order to boost the consistency of herbal quality, C. officinalis is recommended to harvest in 4th growth year. The method of GC-MS combined with multivariate analysis was a powerful tool to evaluate the herbal quality. PMID: 28469699 [PubMed - in process]

PII Protein-Derived FRET Sensors for Quantification and Live-Cell Imaging of 2-Oxoglutarate.

Fri, 05/05/2017 - 14:27
Related Articles PII Protein-Derived FRET Sensors for Quantification and Live-Cell Imaging of 2-Oxoglutarate. Sci Rep. 2017 May 03;7(1):1437 Authors: Lüddecke J, Francois L, Spät P, Watzer B, Chilczuk T, Poschet G, Hell R, Radlwimmer B, Forchhammer K Abstract The citric acid cycle intermediate 2-oxoglutarate (2-OG, a.k.a. alpha-ketoglutarate) links the carbon and nitrogen metabolic pathways and can provide information on the metabolic status of cells. In recent years, it has become exceedingly clear that 2-OG also acts as a master regulator of diverse biologic processes in all domains of life. Consequently, there is a great demand for time-resolved data on 2-OG fluctuations that can't be adequately addressed using established methods like mass spectrometry-based metabolomics analysis. Therefore, we set out to develop a novel intramolecular 2-OG FRET sensor based on the signal transduction protein PII from Synechococcus elongatus PCC 7942. We created two variants of the sensor, with a dynamic range for 2-OG from 0.1 µM to 0.1 mM or from 10 µM to 10 mM. As proof of concept, we applied the sensors to determine in situ glutamine:2-oxoglutarate aminotransferase (GOGAT) activity in Synechococcus elongatus PCC 7942 cells and measured 2-OG concentrations in cell extracts from Escherichia coli in vitro. Finally, we could show the sensors' functionality in living human cell lines, demonstrating their potential in the context of mechanistic studies and drug screening. PMID: 28469248 [PubMed - in process]

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