PubMed

Comprehensive Profiling of Amino Acid Response Uncovers Unique Methionine-Deprived Response Dependent on Intact Creatine Biosynthesis. PLoS Genet. 2015 Apr;11(4):e1005158 Authors: Tang X, Keenan MM, Wu J, Lin CA, Dubois L, Thompson JW, Freedland SJ, Murphy SK, Chi JT Abstract Besides being building blocks for protein synthesis, amino acids serve a wide variety of cellular functions, including acting as metabolic intermediates for ATP generation and for redox homeostasis. Upon amino acid deprivation, free uncharged tRNAs trigger GCN2-ATF4 to mediate the well-characterized transcriptional amino acid response (AAR). However, it is not clear whether the deprivation of different individual amino acids triggers identical or distinct AARs. Here, we characterized the global transcriptional response upon deprivation of one amino acid at a time. With the exception of glycine, which was not required for the proliferation of MCF7 cells, we found that the deprivation of most amino acids triggered a shared transcriptional response that included the activation of ATF4, p53 and TXNIP. However, there was also significant heterogeneity among different individual AARs. The most dramatic transcriptional response was triggered by methionine deprivation, which activated an extensive and unique response in different cell types. We uncovered that the specific methionine-deprived transcriptional response required creatine biosynthesis. This dependency on creatine biosynthesis was caused by the consumption of S-Adenosyl-L-methionine (SAM) during creatine biosynthesis that helps to deplete SAM under methionine deprivation and reduces histone methylations. As such, the simultaneous deprivation of methionine and sources of creatine biosynthesis (either arginine or glycine) abolished the reduction of histone methylation and the methionine-specific transcriptional response. Arginine-derived ornithine was also required for the complete induction of the methionine-deprived specific gene response. Collectively, our data identify a previously unknown set of heterogeneous amino acid responses and reveal a distinct methionine-deprived transcriptional response that results from the crosstalk of arginine, glycine and methionine metabolism via arginine/glycine-dependent creatine biosynthesis. PMID: 25849282 [PubMed - as supplied by publisher]

Use of Nuclear Magnetic Resonance-Based Metabolomics to Characterize the Biochemical Effects of Naphthalene on Various Organs of Tolerant Mice. PLoS One. 2015;10(4):e0120429 Authors: Lin CY, Huang FP, Ling YS, Liang HJ, Lee SH, Hu MY, Tsao PN Abstract Naphthalene, the most common polycyclic aromatic hydrocarbon, causes airway epithelium injury in mice. Repeated exposure of mice to naphthalene induces airway epithelia that are resistant to further injury. Previous studies revealed that alterations in bioactivation enzymes and increased levels of gamma-glutamylcysteine synthase in the bronchioles protect tolerant mice from naphthalene and its reactive metabolites. In our current study, tolerance was induced in male ICR mice using a total of 7 daily intraperitoneal injections of naphthalene (200 mg/kg). Both naphthalene-tolerant and non-tolerant mice were challenged with a dose of 300 mg/kg naphthalene on day 8 to investigate metabolite differences. The lungs, liver, and kidneys were collected for histopathology 24 h after the challenge dose. Bronchial alveolar lavage fluid (BALF) and both hydrophilic and hydrophobic extracts from each organ were analyzed using nuclear magnetic resonance (NMR)-based metabolomics. The histological results showed no observable injuries to the airway epithelium of naphthalene-tolerant mice when compared with the control. In contrast, airway injuries were observed in mice given a single challenge dose (injury mice). The metabolomics analysis revealed that the energy metabolism in the lungs of tolerant and injury mice was significantly perturbed. However, antioxidant metabolites, such as glutathione and succinate, were significantly increased in the lungs of tolerant mice, suggesting a role for these compounds in the protection of organs from naphthalene-induced electrophilic metabolites and free radicals. Damage to the airway cellular membrane, as shown by histopathological results and increased acetone in the BALF and perturbation of hydrophobic lung extracts, including cholesterol, phosphorylcholine-containing lipids, and fatty acyl chains, were observed in injury mice. Consistent with our histopathological results, fewer metabolic effects were observed in the liver and kidney of mice after naphthalene treatments. In conclusion, NMR-based metabolomics reveals possible mechanisms of naphthalene tolerance and naphthalene-induced toxicity in the respiratory system of mice. PMID: 25849086 [PubMed - as supplied by publisher]

Pleiotropic effect of chromosome 5A and the mvp mutation on the metabolite profile during cold acclimation and the vegetative/generative transition in wheat. BMC Plant Biol. 2015;15(1):57 Authors: Juhász Z, Boldizsár Á, Nagy T, Kocsy G, Marincs F, Galiba G, Bánfalvi Z Abstract BACKGROUND: Wheat is the leading source of vegetable protein in the human diet, and metabolites are crucial for both plant development and human nutrition. The recent advances in metabolomics provided an opportunity to perform an untargeted metabolite analysis in this important crop. RESULTS: Wheat was characterised at the metabolite level during cold acclimation and transition from the vegetative to the generative phase. The relationship between these changes and chromosome 5A and the maintained vegetative phase (mvp) mutation was also investigated. Samples were taken from the shoots and crowns during four developmental stages: plants grown at 20/17°C, after cold treatment but still during the vegetative phase, at the double ridge and during spikelet formation. The levels of 47 compounds were identified by gas chromatography-mass spectrometry, of which 38 were annotated. The cold treatment, in general, increased the concentrations of osmolites but not in all lines and not equally in the shoots and crowns. The accumulation of proline was not associated with the vernalisation process or with frost tolerance. The mvp mutation and chromosome 5A substitutions altered the amounts of several metabolites compared to those of the Tm and CS, respectively, during each developmental stage. The Ch5A substitution resulted in more substantial changes at the metabolite level than did the Tsp5A substitution. While Ch5A mainly influenced the sugar concentrations, Tsp5A altered the level of tricarboxylic acid cycle intermediates during the vegetative/generative transition. A much higher trehalose, proline, glutamine, asparagine, and unidentified m/z 186 content was detected in crowns than in shoots that may contribute to the frost tolerance of crowns. CONCLUSIONS: Substantial influences of chromosome 5A and the mvp mutation on metabolism during four different developmental stages were demonstrated. The distinct and overlapping accumulation patterns of metabolites suggest the complex genetic regulation of metabolism in the shoots and crowns. PMID: 25848884 [PubMed - as supplied by publisher]

MetaMapR: Pathway Independent Metabolomic Network Analysis Incorporating Unknowns. Bioinformatics. 2015 Apr 5; Authors: Grapov D, Wanichthanarak K, Fiehn O Abstract Metabolic network mapping is a widely used approach for integration of metabolomic experimental results with biological domain knowledge. However current approaches can be limited by biochemical domain or pathway knowledge which results in sparse disconnected graphs for real world metabolomic experiments. MetaMapR integrates enzymatic transformations with metabolite structural similarity, mass spectral similarity and empirical associations to generate richly connected metabolic networks. This open source, web-based or desktop software, written in the R programming language, leverages KEGG and PubChem databases to derive associations between metabolites even in cases where biochemical domain or molecular annotations are unknown. Network calculation is enhanced through an interface to the Chemical Translation System, which allows metabolite identifier translation between >200 common biochemical databases. Analysis results are presented as interactive visualizations or can be exported as high-quality graphics and numerical tables which can be imported into common network analysis and visualization tools. AVAILABILITY AND IMPLEMENTATION: Freely available at http://dgrapov.github.io/MetaMapR/. Requires R and a modern web browser. CONTACT: Oliver Fiehn - ofiehn@ucdavis.edu Supplementary information: Installation instructions, tutorials and application examples are available at http://dgrapov.github.io/MetaMapR/. PMID: 25847005 [PubMed - as supplied by publisher]

Effect of sublethal preculturing on the survival of probiotics and metabolite formation in set-yoghurt. Food Microbiol. 2015 Aug;49:104-15 Authors: Settachaimongkon S, van Valenberg HJ, Winata V, Wang X, Nout MJ, van Hooijdonk TC, Zwietering MH, Smid EJ Abstract The objective of this study was to investigate the effect of preculturing of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB12 under sublethal stress conditions on their survival and metabolite formation in set-yoghurt. Prior to co-cultivation with yoghurt starters in milk, the two probiotic strains were precultured under sublethal stress conditions (combinations of elevated NaCl and low pH) in a batch fermentor. The activity of sublethally precultured probiotics was evaluated during fermentation and refrigerated storage by monitoring bacterial population dynamics, milk acidification and changes in volatile and non-volatile metabolite profiles of set-yoghurt. The results demonstrated adaptive stress responses of the two probiotic strains resulting in their viability improvement without adverse influence on milk acidification. A complementary metabolomic approach using SPME-GC/MS and (1)H-NMR resulted in the identification of 35 volatiles and 43 non-volatile polar metabolites, respectively. Principal component analysis revealed substantial impact of the activity of sublethally precultured probiotics on metabolite formation demonstrated by distinctive volatile and non-volatile metabolite profiles of set-yoghurt. Changes in relative abundance of various aroma compounds suggest that incorporation of stress-adapted probiotics considerably influences the organoleptic quality of product. This study provides new information on the application of stress-adapted probiotics in an actual food-carrier environment. PMID: 25846920 [PubMed - in process]

Gut microbiome composition and metabolomic profiles of wild western lowland gorillas (Gorilla gorilla gorilla) reflect host ecology. Mol Ecol. 2015 Apr 6; Authors: Gomez A, Petrzelkova K, Yeoman CJ, Vlckova K, Mrázek J, Koppova I, Carbonero F, Ulanov A, Modry D, Todd A, Torralba M, Nelson K, Gaskins HR, Wilson B, Stumpf RM, White BA, Leigh SR Abstract The metabolic activities of gut microbes significantly influence host physiology; thus, characterizing the forces that modulate this micro-ecosystem is key to understanding mammalian biology and fitness. To investigate the gut microbiome of wild primates and determine how this microbial communities respond to the host's external environment, we characterized fecal bacterial communities and, for the first time, gut metabolomes of four wild lowland gorilla groups in the Dzanga Sangha Protected Areas, Central African Republic. Results show that geographical range may be an important modulator of the gut microbiomes and metabolomes of these gorilla groups. Distinctions seemed to relate to feeding behavior; implying energy harvest thorough increased fruit consumption or fermentation of highly fibrous foods. These observations were supported by differential abundance of metabolites and bacterial taxa associated to the metabolism of cellulose, phenolics, organic acids, simple sugars, lipids and sterols between gorillas occupying different geographical ranges. Additionally, the gut microbiomes of a gorilla group under increased anthropogenic pressure could always be distinguished from that of all other groups. By characterizing the interplay between environment, behavior, diet and symbiotic gut microbes we present an alternative perspective on primate ecology and on the forces that shape the gut microbiomes of wild primates from an evolutionary context. This article is protected by copyright. All rights reserved. PMID: 25846719 [PubMed - as supplied by publisher]

Targeted metabolic profiling of wounds in diabetic and non-diabetic mice. Wound Repair Regen. 2015 Apr 4; Authors: Sood RF, Gu H, Djukovic D, Deng L, Ga M, Muffley LA, Raftery D, Hocking AM Abstract While cellular metabolism is known to regulate a number of key biological processes such as cell growth and proliferation, its role in wound healing is unknown. We hypothesized that cutaneous injury would induce significant metabolic changes and that the impaired wound healing seen in diabetes would be associated with a dysfunctional metabolic response to injury. We used a targeted metabolomics approach to characterize the metabolic profile of uninjured skin and full-thickness wounds at day 7 post-injury in non-diabetic (db/-) and diabetic (db/db) mice. By liquid chromatography mass spectrometry, we identified 129 metabolites among all tissue samples. Principal component analysis demonstrated that uninjured skin and wounds have distinct metabolic profiles and that diabetes alters the metabolic profile of both uninjured skin and wounds. Examining individual metabolites, we identified 62 with a significantly altered response to injury in the diabetic mice, with many of these, including glycine, kynurenate, and OH-phenylpyruvate, implicated in wound healing for the first time. Thus, we report the first comprehensive analysis of wound metabolic profiles, and our results highlight the potential for metabolomics to identify novel biomarkers and therapeutic targets for improved wound healing outcomes. This article is protected by copyright. All rights reserved. PMID: 25845676 [PubMed - as supplied by publisher]

Plasma lipid analysis by hydrophilic interaction liquid chromatography coupled with electrospray ionization tandem mass spectrometry. J Sep Sci. 2015 Apr 3; Authors: Sonomura K, Kudoh S, Sato TA, Matsuda F Abstract A novel method for the analysis of endogenous lipids and related compounds was developed employing hydrophilic interaction liquid chromatography with electrospray ionization tandem mass spectrometry. A hydrophilic interaction liquid chromatography with carbamoyl stationary phase achieved clear separation of phosphatidylcholine, lysophosphatidylcholine, sphingomyelin, ceramide, and mono-hexsosyl ceramide groups with good peak area repeatability (RSD% < 10) and linearity (R(2) > 0.99). The established method was applied to human plasma assays and a total of 117 endogenous lipids were successfully detected and reproducibly identified. In addition, we investigated the simultaneous detection of small polar metabolites such as amino and organic acids co-existing in the same biological samples processed in a single analytical run with lipids. Our results show that hydrophilic interaction liquid chromatography is a useful tool for human plasma lipidome analysis and offers more comprehensive metabolome coverage. This article is protected by copyright. All rights reserved. PMID: 25845351 [PubMed - as supplied by publisher]

Related Articles Proteogenomics: emergence and promise. Cell Mol Life Sci. 2015 Mar;72(5):953-7 Authors: Faulkner S, Dun MD, Hondermarck H Abstract Proteogenomics, or the integration of proteomics with genomics and transcriptomics, is emerging as the next step towards a unified understanding of cellular functions. Looking globally and simultaneously at gene structure, RNA expression, protein synthesis and post-translational modifications have become technically feasible and offer a new perspective to molecular processes. Recent publications have highlighted the value of proteogenomics in oncology for defining the molecular signature of human tumors, and translation to other areas of biomedicine and life sciences is anticipated. This mini-review will discuss recent developments, challenges and perspectives in proteogenomics. PMID: 25609363 [PubMed - indexed for MEDLINE]

Related Articles Quantification of endogenous metabolites by the postcolumn infused-internal standard method combined with matrix normalization factor in liquid chromatography-electrospray ionization tandem mass spectrometry. J Chromatogr A. 2015 Jan 2;1375:62-8 Authors: Liao HW, Chen GY, Wu MS, Liao WC, Tsai IL, Kuo CH Abstract Quantification of endogenous metabolites has enabled the discovery of biomarkers for diagnosis and provided for an understanding of disease etiology. The standard addition and stable isotope labeled-internal standard (SIL-IS) methods are currently the most widely used approaches to quantifying endogenous metabolites, but both have some limitations for clinical measurement. In this study, we developed a new approach for endogenous metabolite quantification by the postcolumn infused-internal standard (PCI-IS) method combined with the matrix normalization factor (MNF) method. MNF was used to correct the difference in MEs between standard solution and biofluids, and PCI-IS additionally tailored the correction of the MEs for individual samples. Androstenedione and testosterone were selected as test articles to verify this new approach to quantifying metabolites in plasma. The repeatability (n=4 runs) and intermediate precision (n=3 days) in terms of the peak area of androstenedione and testosterone at all tested concentrations were all less than 11% relative standard deviation (RSD). The accuracy test revealed that the recoveries were between 95.72% and 113.46%. The concentrations of androstenedione and testosterone in fifty plasma samples obtained from healthy volunteers were quantified by the PCI-IS combined with the MNF method, and the quantification results were compared with the results of the SIL-IS method. The Pearson correlation test showed that the correlation coefficient was 0.98 for both androstenedione and testosterone. We demonstrated that the PCI-IS combined with the MNF method is an effective and accurate method for quantifying endogenous metabolites. PMID: 25516166 [PubMed - indexed for MEDLINE]

Mass spectral similarity for untargeted metabolomics data analysis of complex mixtures. Int J Mass Spectrom. 2015 Feb 1;377:719-717 Authors: Garg N, Kapono C, Lim YW, Koyama N, Vermeij MJ, Conrad D, Rohwer F, Dorrestein PC Abstract While in nucleotide sequencing, the analysis of DNA from complex mixtures of organisms is common, this is not yet true for mass spectrometric data analysis of complex mixtures. The comparative analyses of mass spectrometry data of microbial communities at the molecular level is difficult to perform, especially in the context of a host. The challenge does not lie in generating the mass spectrometry data, rather much of the difficulty falls in the realm of how to derive relevant information from this data. The informatics based techniques to visualize and organize datasets are well established for metagenome sequencing; however, due to the scarcity of informatics strategies in mass spectrometry, it is currently difficult to cross correlate two very different mass spectrometry data sets from microbial communities and their hosts. We highlight that molecular networking can be used as an organizational tool of tandem mass spectrometry data, automated database search for rapid identification of metabolites, and as a workflow to manage and compare mass spectrometry data from complex mixtures of organisms. To demonstrate this platform, we show data analysis from hard corals and a human lung associated with cystic fibrosis. PMID: 25844058 [PubMed - as supplied by publisher]

The biomarkers of fetal growth in intrauterine growth retardation and large for gestational age cases: from adipocytokines to a metabolomic all-in-one tool. Expert Rev Proteomics. 2015 Apr 5;:1-8 Authors: Dessì A, Pravettoni C, Cesare Marincola F, Schirru A, Fanos V Abstract Adipose tissue is no longer considered as inert; the literature describes the role it plays in the production of many substances, such as adiponectin, visfatin, ghrelin, S100B, apelin, TNF, IL-6 and leptin. These molecules have specific roles in humans and their potential as biomarkers useful for identifying alterations related to intrauterine growth retardation and large for gestational age neonates is emerging. Infants born in such conditions have undergone metabolic changes, such as fetal hypo- or hyperinsulinemia, which may lead to development of dysmetabolic syndrome and other chronic diseases in adulthood. In this review, these biomarkers are analyzed specifically and it is discussed how metabolomics may be an advantageous tool for detection, discrimination and prediction of metabolic alterations and diseases. Thus, a holistic approach, such as metabolomics, could help the prevention and early diagnosis of metabolic syndrome. PMID: 25843159 [PubMed - as supplied by publisher]

Related Articles Identification of anti-HIV active dicaffeoylquinic - and tricaffeoylquinic acids in Helichrysum populifolium by NMR-based metabolomic guided fractionation. Fitoterapia. 2015 Apr 1; Authors: Heyman HM, Senejoux F, Seibert I, Klimkait T, Maharaj VJ, Meyer JJ Abstract South Africa being home to more than 35% of the world's Helichrysum species (c.a. 244) of which many are used in traditional medicine, is seen potentially as a significant resource in the search of new anti-HIV chemical entities. It was established that five of the 30 Helichrysum species selected for this study had significant anti-HIV activity ranging between 12 - 21μg/mL (IC50) by using an in-house developed DeCIPhR method on a full virus model. Subsequent toxicity tests also revealed little or no toxicity for these active extracts. With the use of NMR-based metabolomics, the search for common chemical characteristics within the plant extract was conducted, which resulted in specific chemical shift areas identified that could be linked to the anti-HIV activity of the extracts. The NMR chemical shifts associated with the activity were identified to be 2.56 - 3.08ppm, 5.24 - 6.28ppm, 6.44 - 7.04ppm and 7.24 - 8.04ppm. This activity profile was then used to guide the fractionation process by narrowing down and focusing the fractionation and purification process to speed up the putative identification of five compounds with anti-HIV activity in the most active species, H. populifolium. The anti-HIV compounds identified for the first time from H. populifolium were three dicaffeoylquinic acid derivatives, i.e. 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid as well as two tricaffeoylquinic acid derivatives i.e. 1,3,5-tricaffeoylquinic acid and either 5-malonyl-1,3,4-tricaffeoylquinic or 3-malonyl-1,4,5-tricaffeoylquinic acid, with the latter being identified for the first time in the genus. PMID: 25841639 [PubMed - as supplied by publisher]

Related Articles The changing world of drug development. Chin Clin Oncol. 2014 Jun;3(2):12 Authors: Dittrich C Abstract Cancer drug development is undergoing a substantial shift nowadays. The underlying drivers are multi-factorial. On the one side, drug development is performed more rationally than ever, profiting from the scientific advances in molecular biology in general and the elucidation of the various "omes" from genome to metabolome in particular. On the other side, it is based on enormous technological progress, e.g., in the field of genome sequencing, and in that of adequate handling of the resulting plethora of data. The high attrition rate of oncologic drugs under development in the past and the pressure from the side of the payers make it necessary to find permanently new answers for and adaptations of the process of drug development. In this context, it is necessary to respect arguments and views from the various perspectives of all the relevant stakeholders. Together with a group of international experts from different perspectives of drug development, this special issue will illustrate the respective role of patients, laboratory, clinical trials, drug companies, regulatory bodies, and also the economic principle in drug development, aiming at facilitating drug research in the near future. PMID: 25841409 [PubMed - in process]

Related Articles Plant metabolite profiles and the buffering capacities of ecosystems. Phytochemistry. 2015 Feb;110:6-12 Authors: Fester T Abstract In spite of some inherent challenges, metabolite profiling is becoming increasingly popular under field conditions. It has been used successfully to address topics like species interactions, connections between growth and chemical stoichiometry or the plant's stress response. Stress exerts a particularly clear impact on plant metabolomes and has become a central topic in many metabolite profiling experiments in the fields. In contrast to phytochambers, however, external stress is often at least partially absorbed by the environment when measuring under field conditions. Such stress-buffering capacities of (agro)-ecosystems are of crucial interest given the ever-increasing anthropogenic impact on ecosystems and this review promotes the idea of using plant metabolite profiles for respective measurements. More specifically I propose to use parameters of the response of key plant species to a given stress treatment as proxies for measuring and comparing stress-buffering capacities of ecosystems. Stress response parameters accessible by metabolite profiling comprise for example the intensity or duration of the impact of stress or the ability of the plant organism to recover from this impact after a given time. Analyses of ecosystem stress-buffering capacities may improve our understanding of how ecosystems cope with stress and may improve our abilities to predict ecosystem changes. PMID: 25564262 [PubMed - indexed for MEDLINE]

Related Articles Metabolic profiling of Commiphora wightii (guggul) reveals a potential source for pharmaceuticals and nutraceuticals. Phytochemistry. 2015 Feb;110:29-36 Authors: Bhatia A, Bharti SK, Tripathi T, Mishra A, Sidhu OP, Roy R, Nautiyal CS Abstract Guggul gum resin from Commiphora wightii (syn. Commiphoramukul) has been used for centuries in Ayurveda to treat a variety of ailments. The NMR and GC-MS based non-targeted metabolite profiling identified 118 chemically diverse metabolites including amino acids, fatty acids, organic acids, phenolic acids, pregnane-derivatives, steroids, sterols, sugars, sugar alcohol, terpenoids, and tocopherol from aqueous and non-aqueous extracts of leaves, stem, roots, latex and fruits of C. wightii. Out of 118, 51 structurally diverse aqueous metabolites were characterized by NMR spectroscopy. For the first time quinic acid and myo-inositol were identified as the major metabolites in C. wightii. Very high concentration of quinic acid was found in fruits (553.5 ± 39.38 mg g(-1) dry wt.) and leaves (212.9 ± 10.37 mg g(-1) dry wt.). Similarly, high concentration of myo-inositol (168.8 ± 13.84 mg g(-1) dry wt.) was observed from fruits. The other metabolites of cosmeceutical, medicinal, nutraceutical and industrial significance such as α-tocopherol, n-methylpyrrolidone (NMP), trans-farnesol, prostaglandin F2, protocatechuic, gallic and cinnamic acids were identified from non-aqueous extracts using GC-MS. These important metabolites have thus far not been reported from this plant. Isolation of a fungal endophyte, (Nigrospora sps.) from this plant is the first report. The fungal endophyte produced a substantial quantity of bostrycin and deoxybostrycin known for their antitumor properties. Very high concentrations of quinic acid and myo-inositol in leaves and fruits; a substantial quantity of α-tocopherol and NMP in leaves, trans-farnesol in fruits, bostrycin and deoxybostrycin from its endophyte makes the taxa distinct, since these metabolites with medicinal properties find immense applications as dietary supplements and nutraceuticals. PMID: 25561401 [PubMed - indexed for MEDLINE]

Related Articles Pyruvate kinase isoform expression alters nucleotide synthesis to impact cell proliferation. Mol Cell. 2015 Jan 8;57(1):95-107 Authors: Lunt SY, Muralidhar V, Hosios AM, Israelsen WJ, Gui DY, Newhouse L, Ogrodzinski M, Hecht V, Xu K, Acevedo PN, Hollern DP, Bellinger G, Dayton TL, Christen S, Elia I, Dinh AT, Stephanopoulos G, Manalis SR, Yaffe MB, Andrechek ER, Fendt SM, Vander Heiden MG Abstract Metabolic regulation influences cell proliferation. The influence of pyruvate kinase isoforms on tumor cells has been extensively studied, but whether PKM2 is required for normal cell proliferation is unknown. We examine how PKM2 deletion affects proliferation and metabolism in nontransformed, nonimmortalized PKM2-expressing primary cells. We find that deletion of PKM2 in primary cells results in PKM1 expression and proliferation arrest. PKM1 expression, rather than PKM2 loss, is responsible for this effect, and proliferation arrest cannot be explained by cell differentiation, senescence, death, changes in gene expression, or prevention of cell growth. Instead, PKM1 expression impairs nucleotide production and the ability to synthesize DNA and progress through the cell cycle. Nucleotide biosynthesis is limiting, as proliferation arrest is characterized by severe thymidine depletion, and supplying exogenous thymine rescues both nucleotide levels and cell proliferation. Thus, PKM1 expression promotes a metabolic state that is unable to support DNA synthesis. PMID: 25482511 [PubMed - indexed for MEDLINE]

Related Articles Comprehensive analysis of lipid composition in crude palm oil using multiple lipidomic approaches. J Genet Genomics. 2014 May 20;41(5):293-304 Authors: Cheong WF, Wenk MR, Shui G Abstract Palm oil is currently the leading edible oil consumed worldwide. Triacylglycerol (TAG) and diacylglycerol (DAG) are the dominant lipid classes in palm oil. Other lipid classes present in crude palm oil, such as phospholipids and galactolipids, are very low in abundance. These low-abundance lipids constitute key intermediates in lipid biosynthesis. In this study, we applied multiple lipidomic approaches, including high-sensitivity and high-specificity multiple reaction monitoring, to comprehensively quantify individual lipid species in crude palm oil. We also established a new liquid chromatography-coupled mass spectrometry method that allows direct quantification of low-abundance galactolipids in palm oil without the need for sample pretreatment. As crude palm oil contains large amounts of neutral lipids, our direct-detection method circumvents many of the challenges encountered with conventional lipid quantification methods. This approach allows direct measurement of lipids with no hassle during sample preparation and is more accurate and precise compared with other methods. PMID: 24894356 [PubMed - indexed for MEDLINE]

Related Articles A lipidomic perspective on intermediates in cholesterol synthesis as indicators of disease status. J Genet Genomics. 2014 May 20;41(5):275-82 Authors: Sharpe LJ, Burns V, Brown AJ Abstract Lipidomics is increasingly becoming a viable method for researchers to routinely identify the various sterols present in samples, beyond just measuring cholesterol itself. In particular, the measurement of intermediates in cholesterol synthesis can shed new insights into not only the flux through the pathway, but also numerous disease states where levels of sterol intermediates are drastically altered. In this review, we indicate several intermediates that are relevant to disease, and discuss the challenges for analysing them, including the need for standardised methodology or universal controls across the lipidomics field. PMID: 24894354 [PubMed - indexed for MEDLINE]

Related Articles Cordyceps sinensis protects against liver and heart injuries in a rat model of chronic kidney disease: a metabolomic analysis. Acta Pharmacol Sin. 2014 May;35(5):697-706 Authors: Liu X, Zhong F, Tang XL, Lian FL, Zhou Q, Guo SM, Liu JF, Sun P, Hao X, Lu Y, Wang WM, Chen N, Zhang NX Abstract AIM: To test the hypothesis that the traditional Chinese medicine Cordyceps sinensis could improve the metabolic function of extrarenal organs to achieve its anti-chronic kidney disease (CKD) effects. METHODS: Male SD rats were divided into CKD rats (with 5/6-nephrectomy), CKD rats treated with Cordyceps sinensis (4 mg•kg-1•d-1, po), and sham-operated rats. After an 8-week treatment, metabolites were extracted from the hearts and livers of the rats, and then subjected to (1)H-NMR-based metabolomic analysis. RESULTS: Oxidative stress, energy metabolism, amino acid and protein metabolism and choline metabolism were considered as links between CKD and extrarenal organ dysfunction. Within the experimental period of 8 weeks, the metabolic disorders in the liver were more pronounced than in the heart, suggesting that CKD-related extrarenal organ dysfunctions occurred sequentially rather than simultaneously. Oral administration of Cordyceps sinensis exerted statistically significant rescue effects on the liver and heart by reversely regulating levels of those metabolites that are typically perturbed in CKD. CONCLUSION: Oral administration of Cordyceps sinensis significantly attenuates the liver and heart injuries in CKD rats. The (1)H NMR-based metabolomic approach has provided a systematic view for understanding of CKD and the drug treatment, which can also be used to elucidate the mechanisms of action of other traditional Chinese medicines. PMID: 24632844 [PubMed - indexed for MEDLINE]