PubMed

Metabolome and transcriptome profiling reveal new insights into somatic embryo germination in Norway spruce (Picea abies). Tree Physiol. 2017 Jun 28;:1-15 Authors: Dobrowolska I, Businge E, Abreu IN, Moritz T, Egertsdotter U, Plomion C Abstract Transcriptome, metabolome and histological profiling were performed on normal and aberrant somatic embryo germinants of Norway spruce (Picea abies L. Karst) providing a simplistic systems biology description of conifer germination. Aberrant germinants (AGs) formed periderm-like tissue at the apical pole and lacked shoot growth above the cotyledons. Transcriptome profiling (RNA-Sequencing) revealed a total of 370 differentially expressed genes at ≥1 or ≤-1 log2-fold change, where 92% were down-regulated in AGs compared with normal germinants (NGs). Genes associated with shoot apical meristem formation were down-regulated in AGs, or not differentially expressed between AGs and NGs. Genes involved in hormone signaling and transport were also down-regulated. Metabolite profiling by gas chromatography-mass spectrometry (MS) and liquid chromatography-MS revealed biochemical difference between AGs and NGs, notably increased levels of sugars including glucose in AGs. Genes involved in glucose signaling were down-regulated and genes involved in starch biosynthesis were up-regulated, suggesting involvement of sugar signaling during late embryo development and germination. The overall results provide new data enabling further studies to confirm potential markers for a normal germination process in conifers. PMID: 28985382 [PubMed - as supplied by publisher]

A molecular approach to drought-induced reduction in leaf CO2 exchange in drought-resistant Quercus ilex. Physiol Plant. 2017 Oct 06;: Authors: Rodríguez-Calcerrada J, Rodrigues AM, Perdiguero P, António C, Atkin OK, Li M, Collada C, Gil L Abstract Drought-induced reduction of leaf gas exchange entails a complex regulation of the plant leaf metabolism. We used a combined molecular and physiological approach to understand leaf photosynthetic and respiratory responses of two-year-old Quercus ilex seedlings to drought. Mild drought stress resulted in glucose accumulation while net photosynthetic CO2 uptake (Pn ) remained unchanged, suggesting a role of glucose in stress signaling and/or osmoregulation. Simple sugars and sugar alcohols increased throughout moderate to very severe drought stress conditions, in parallel to a progressive decline in Pn and the quantum efficiency of photosystem II; by contrast, minor changes occurred in respiration rates until drought stress was very severe. At very severe drought stress, 2-oxoglutarate dehydrogenase complex gene expression significantly decreased, and the abundance of most amino acids dramatically increased, especially that of proline and γ-aminobutyric acid (GABA) suggesting enhanced protection against oxidative damage and a re-organization of the tricarboxylic cycle acid (TCA) cycle via the GABA shunt. All together, our results point to Q. ilex drought tolerance being linked to signaling and osmoregulation by hexoses during early stages of drought stress, and enhanced protection against oxidative damage by polyols and amino acids under severe drought stress. PMID: 28984911 [PubMed - as supplied by publisher]

Remote Sensing between Liver and Intestine: Importance of Microbial Metabolites. Curr Pharmacol Rep. 2017 Jun;3(3):101-113 Authors: Fu ZD, Cui JY Abstract Recent technological advancements including metagenomics sequencing and metabolomics have allowed the discovery of critical functions of gut microbiota in obesity, malnutrition, neurological disorders, asthma, and xenobiotic metabolism. Classification of the human gut microbiome into distinct "enterotypes" has been proposed to serve as a new paradigm for understanding the interplay between microbial variation and human disease phenotypes, as many organs are affected by gut microbiota modifications during the pathogenesis of diseases. Gut microbiota remotely interacts with liver and other metabolic organs of the host through various microbial metabolites that are absorbed into the systemic circulation. PURPOSE OF REVIEW: The present review summarizes recent literature regarding the importance of gut microbiota in modulating the physiological and pathological responses of various host organs, and describes the functions of the known microbial metabolites that are involved in this remote sensing process, with a primary focus on the gut microbiota-liver axis. RECENT FINDINGS: Under physiological conditions, gut microbiota modulates the hepatic transcriptome, proteome, and metabolome, most notably down-regulating cytochrome P450 3a mediated xenobiotic metabolism. Gut microbiome also modulates the rhythmicity in liver gene expression, likely through microbial metabolites, such as butyrate and propionate that serve as epigenetic modifiers. Additionally, the production of host hormones such as primary bile acids and glucagon like peptide 1 is altered by gut microbiota to modify intermediary metabolism of the host. SUMMARY: Dysregulation of gut microbiota is implicated in various liver diseases such as alcoholic liver disease, non-alcoholic steatohepatitis, liver cirrhosis, cholangitis, and liver cancer. Gut microbiota modifiers such as probiotics and prebiotics are increasingly recognized as novel therapeutic modalities for liver and other types of human diseases. PMID: 28983453 [PubMed]

Studying the Differences of Bacterial Metabolome and Microbiome in the Colon between Landrace and Meihua Piglets. Front Microbiol. 2017;8:1812 Authors: Yan S, Zhu C, Yu T, Huang W, Huang J, Kong Q, Shi J, Chen Z, Liu Q, Wang S, Jiang Z, Chen Z Abstract This study was conducted to compare the microbiome and metabolome differences in the colon lumen from two pig breeds with different genetic backgrounds. Fourteen weaned piglets at 30 days of age, including seven Landrace piglets (a lean-type pig breed with a fast growth rate) and seven Meihua piglets (a fatty-type Chinese local pig breed with a slow growth rate), were fed the same diets for 35 days. Untargeted metabolomics analyses showed that a total of 401 metabolites differed between Landrace and Meihua. Seventy of these 401 metabolites were conclusively identified. Landrace accumulated more short-chain fatty acids (SCFAs) and secondary bile acids in the colon lumen. Moreover, expression of the SCFAs transporter (solute carrier family 5 member 8, SLC5A8) and receptor (G protein-coupled receptor 41, GPR41) in the colon mucosa was higher, while the bile acids receptor (farnesoid X receptor, FXR) had lower expression in Landrace compared to Meihua. The relative abundances of 8 genera and 16 species of bacteria differed significantly between Landrace and Meihua, and were closely related to the colonic concentrations of bile acids or SCFAs based on Pearson's correlation analysis. Collectively, our results demonstrate for the first time that there were differences in the colonic microbiome and metabolome between Meihua and Landrace piglets, with the most profound disparity in production of SCFAs and secondary bile acids. PMID: 28983290 [PubMed]

Metabolomic analysis of insulin resistance across different mouse strains and diets. J Biol Chem. 2017 Oct 05;: Authors: Stöckli J, Fisher-Wellman KH, Chaudhuri R, Zeng XY, Fazakerley DJ, Meoli CC, Thomas KC, Hoffman NJ, Mangiafico SP, Xirouchaki CE, Yang CH, Ilkayeva O, Wong K, Cooney GJ, Andrikopoulos S, Muoio DM, James DE Abstract Insulin resistance is a major risk factor for many diseases. However, its underlying mechanism remains unclear in part because it is triggered by a complex relationship between multiple factors including genes and the environment. Here we used metabolomics combined with computational methods to identify factors that classified insulin resistance across individual mice derived from three different mouse strains fed two different diets. Three inbred ILSXISS strains were fed high fat or chow diets and subjected to metabolic phenotyping and metabolomics analysis of skeletal muscle. There was significant metabolic heterogeneity between strains, diet and individual animals. Distinct metabolites were changed with insulin resistance, diet and between strains. Computational analysis revealed 113 metabolites that were correlated with metabolic phenotypes. Using these 113 metabolites, combined with machine learning to segregate mice based on insulin sensitivity we identified C22:1-CoA, C2-carnitine and C16-ceramide as the best classifiers. Strikingly, when these three metabolites were combined into one signature, they classified mice based on insulin sensitivity more accurately than each metabolite on its own or other published metabolic signatures. Furthermore, C22:1-CoA, was 2.3-fold higher in insulin resistant mice and correlated significantly with insulin resistance. We have identified a metabolomic signature comprised of three functionally unrelated metabolites that accurately predicts whole body insulin sensitivity across three mouse strains. These data indicate the power of simultaneous analysis of individual, genetic and environmental variance in mice for identifying novel factors that accurately predict metabolic phenotypes like whole body insulin sensitivity. PMID: 28982973 [PubMed - as supplied by publisher]

Another case for diet restriction: TAp73-expressing medulloblastomas are stunted by glutamine withdrawal. Genes Dev. 2017 Sep 01;31(17):1715-1716 Authors: Napoli M, Flores ER Abstract Medulloblastomas are among the most common malignant brain cancers in the pediatric population and consist of at least four distinct subgroups with unique molecular and genetic features and clinical outcomes. In this issue of Genes & Development, Niklison-Chirou and colleagues (pp. 1738-1753) identify the p53 family member and p73 isoform TAp73 as a crucial factor causing glutamine addiction in aggressive medulloblastomas. Their findings pave the way for the use of glutamine restriction as an adjuvant treatment for TAp73-expressing medulloblastomas. PMID: 28982757 [PubMed - in process]

Related Articles Metabolomic profile and nucleoside composition of Cordyceps nidus sp. nov. (Cordycipitaceae): A new source of active compounds. PLoS One. 2017;12(6):e0179428 Authors: Chiriví J, Danies G, Sierra R, Schauer N, Trenkamp S, Restrepo S, Sanjuan T Abstract Cordyceps sensu lato is a genus of arthropod-pathogenic fungi, which have been used traditionally as medicinal in Asia. Within the genus, Ophiocordyceps sinensis is the most coveted and expensive species in China. Nevertheless, harvesting wild specimens has become a challenge given that natural populations of the fungus are decreasing and because large-scale culture of it has not yet been achieved. The worldwide demand for products derived from cultivable fungal species with medicinal properties has increased recently. In this study, we propose a new species, Cordyceps nidus, which parasitizes underground nests of trapdoor spiders. This species is phylogenetically related to Cordyceps militaris, Cordyceps pruinosa, and a sibling species of Cordyceps caloceroides. It is found in tropical rainforests from Bolivia, Brazil, Colombia and Ecuador. We also investigated the medicinal potential of this fungus based on its biochemical properties when grown on four different culture media. The metabolic profile particularly that of nucleosides, in polar and non-polar extracts was determined by UPLC, and then correlated to their antimicrobial activity and total phenolic content. The metabolome showed a high and significant dependency on the substrate used for fungal growth. The mass intensities of nucleosides and derivative compounds were higher in natural culture media in comparison to artificial culture media. Among these compounds, cordycepin was the predominant, showing the potential use of this species as an alternative to O. sinensis. Furthermore, methanol fractions showed antimicrobial activity against gram-positive bacteria, and less than 3.00 mg of gallic acid equivalents per g of dried extract were obtained when assessing its total phenolic content by modified Folin-Ciocalteu method. The presence of polyphenols opens the possibility of further exploring the antioxidant capacity and the conditions that may enhance this characteristic. The metabolic composition and biochemical activity indicate potential use of C. nidus in pharmaceutical applications. PMID: 28636672 [PubMed - indexed for MEDLINE]

Related Articles FUM2, a Cytosolic Fumarase, Is Essential for Acclimation to Low Temperature in Arabidopsis thaliana. Plant Physiol. 2016 Sep;172(1):118-27 Authors: Dyson BC, Miller MA, Feil R, Rattray N, Bowsher CG, Goodacre R, Lunn JE, Johnson GN Abstract Although cold acclimation is a key process in plants from temperate climates, the mechanisms sensing low temperature remain obscure. Here, we show that the accumulation of the organic acid fumaric acid, mediated by the cytosolic fumarase FUM2, is essential for cold acclimation of metabolism in the cold-tolerant model species Arabidopsis (Arabidopsis thaliana). A nontargeted metabolomic approach, using gas chromatography-mass spectrometry, identifies fumarate as a key component of the cold response in this species. Plants of T-DNA insertion mutants, lacking FUM2, show marked differences in their response to cold, with contrasting responses both in terms of metabolite concentrations and gene expression. The fum2 plants accumulated higher concentrations of phosphorylated sugar intermediates and of starch and malate. Transcripts for proteins involved in photosynthesis were markedly down-regulated in fum2.2 but not in wild-type Columbia-0. Plants of fum2 show a complete loss of the ability to acclimate photosynthesis to low temperature. We conclude that fumarate accumulation plays an essential role in low temperature sensing in Arabidopsis, either indirectly modulating metabolic or redox signals or possibly being itself directly involved in cold sensing. PMID: 27440755 [PubMed - indexed for MEDLINE]

Related Articles Oxygen Sensing via the Ethylene Response Transcription Factor RAP2.12 Affects Plant Metabolism and Performance under Both Normoxia and Hypoxia. Plant Physiol. 2016 Sep;172(1):141-53 Authors: Paul MV, Iyer S, Amerhauser C, Lehmann M, van Dongen JT, Geigenberger P Abstract Subgroup-VII-ethylene-response-factor (ERF-VII) transcription factors are involved in the regulation of hypoxic gene expression and regulated by proteasome-mediated proteolysis via the oxygen-dependent branch of the N-end-rule pathway. While research into ERF-VII mainly focused on their role to regulate anoxic gene expression, little is known on the impact of this oxygen-sensing system in regulating plant metabolism and growth. By comparing Arabidopsis (Arabidopsis thaliana) plants overexpressing N-end-rule-sensitive and insensitive forms of the ERF-VII-factor RAP2.12, we provide evidence that oxygen-dependent RAP2.12 stability regulates central metabolic processes to sustain growth, development, and anoxic resistance of plants. (1) Under normoxia, overexpression of N-end-rule-insensitive Δ13RAP2.12 led to increased activities of fermentative enzymes and increased accumulation of fermentation products, which were accompanied by decreased adenylate energy states and starch levels, and impaired plant growth and development, indicating a role of oxygen-regulated RAP2.12 degradation to prevent aerobic fermentation. (2) In Δ13RAP2.12-overexpressing plants, decreased carbohydrate reserves also led to a decrease in anoxic resistance, which was prevented by external Suc supply. (3) Overexpression of Δ13RAP2.12 led to decreased respiration rates, changes in the levels of tricarboxylic acid cycle intermediates, and accumulation of a large number of amino acids, including Ala and γ-amino butyric acid, indicating a role of oxygen-regulated RAP2.12 abundance in controlling the flux-modus of the tricarboxylic acid cycle. (4) The increase in amino acids was accompanied by increased levels of immune-regulatory metabolites. These results show that oxygen-sensing, mediating RAP2.12 degradation is indispensable to optimize metabolic performance, plant growth, and development under both normoxic and hypoxic conditions. PMID: 27372243 [PubMed - indexed for MEDLINE]

Urinary metabolic phenotyping of mucopolysaccharidosis type I combining untargeted and targeted strategies with data modeling. Clin Chim Acta. 2017 Oct 02;475:7-14 Authors: Tebani A, Schmitz-Afonso I, Abily-Donval L, Héron B, Piraud M, Ausseil J, Brassier A, De Lonlay P, Zerimech F, Vaz FM, Gonzalez BJ, Marret S, Afonso C, Bekri S Abstract BACKGROUND: Application of metabolic phenotyping could expand the pathophysiological knowledge of mucopolysaccharidoses (MPS) and may reveal the comprehensive metabolic impairments in MPS. However, few studies applied this approach to MPS. METHODS: We applied targeted and untargeted metabolic profiling in urine samples obtained from a French cohort comprising 19 MPS I and 15 MPS I treated patients along with 66 controls. For that purpose, we used ultra-high-performance liquid chromatography combined with ion mobility and high-resolution mass spectrometry following a protocol designed for large-scale metabolomics studies regarding robustness and reproducibility. Furthermore, 24 amino acids have been quantified using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Keratan sulfate, Heparan sulfate and Dermatan sulfate concentrations have also been measured using an LC-MS/MS method. Univariate and multivariate data analyses have been used to select discriminant metabolites. The mummichog algorithm has been used for pathway analysis. RESULTS: The studied groups yielded distinct biochemical phenotypes using multivariate data analysis. Univariate statistics also revealed metabolites that differentiated the groups. Specifically, metabolites related to the amino acid metabolism. Pathway analysis revealed that several major amino acid pathways were dysregulated in MPS. Comparison of targeted and untargeted metabolomics data with in silico results yielded arginine, proline and glutathione metabolisms being the most affected. CONCLUSION: This study is one of the first metabolic phenotyping studies of MPS I. The findings might help to generate new hypotheses about MPS pathophysiology and to develop further targeted studies of a smaller number of potentially key metabolites. PMID: 28982054 [PubMed - as supplied by publisher]

Single Cell Neurometabolomics. ACS Chem Neurosci. 2017 Oct 05;: Authors: Qi M, Philip M, Yang N, Sweedler JV Abstract Metabolomics, the characterization of metabolites and their changes within biological systems, has seen great technological and methodological progress over the past decade. Most metabolomic experiments involve the characterization of the small-molecule content of fluids or tissue homogenates. While these microliter and larger volume metabolomic measurements can characterize hundreds to thousands of compounds, the coverage of molecular content decreases as sample sizes are reduced to the nanoliter and even to the picoliter volume range. Recent progress has enabled the ability to characterize the major molecules found within specific individual cells. Especially within the brain, a myriad of cell types are colocalized and oftentimes only a subset of these cells undergo changes in both healthy and pathological states. Here we highlight recent progress in mass spectrometry-based approaches used for single cell metabolomics, emphasizing their application to neuroscience research. Single cell studies can be directed to measuring differences between members of populations of similar cells (i.e., oligodendrocytes), as well as characterizing differences between cell types (i.e., neurons and astrocytes), and are especially useful for measuring changes occurring during different behavior states, exposure to diets and drugs, neuronal activity, and disease. When combined with other -omics approaches such as transcriptomics, and with morphological and physiological measurements, single cell metabolomics aids fundamental neurochemical studies, has great potential in pharmaceutical development, and should improve the diagnosis and treatment of brain diseases. PMID: 28982006 [PubMed - as supplied by publisher]

MicroRNA-661 modulates redox and metabolic homeostasis in colon cancer. Mol Oncol. 2017 Oct 05;: Authors: Gómez de Cedrón M, Acín Pérez R, Sánchez-Martínez R, Molina S, Herranz J, Feliu J, Reglero G, Enríquez JA, Ramírez de Molina A Abstract Cancer cell survival and metastasis are dependent on metabolic reprogramming that is capable of increasing resistance to oxidative and energetic stress. Targeting these two processes can be crucial for cancer progression. Herein, we describe the role of microRNA-661 (miR661) as epigenetic regulator of colon cancer (CC) cell metabolism. miR661 induces a global increase in reactive oxygen species (ROS), specifically in mitochondrial superoxide anions (SO(-) ), which appears to be mediated by decreased carbohydrate metabolism and pentose phosphate pathway, and by a higher dependency on mitochondrial respiration. miR661 overexpression in non-metastatic human CC cells induces an epithelial-to-mesenchymal transition (EMT) phenotype, and a reduced tolerance to metabolic stress. This seems to be a general effect of miR661 in CC, since metastatic CC cell metabolism is also compromised upon miR661 overexpression. We propose hexose 6 phosphate dehydrogenase (H6PD) and pyruvate kinase M2 (PKM2) as two key players related to the observed metabolic reprogramming. Finally, the clinical relevance of miR661 expression levels in stage-II and III CC patients is discussed. In conclusion, we propose miR661 as a potential modulator of redox and metabolic homeostasis in CC. PMID: 28981199 [PubMed - as supplied by publisher]

Dynamic metabolic reprogramming of steroidal glycol-alkaloid and phenylpropanoid biosynthesis may impart early blight resistance in wild tomato (Solanum arcanum Peralta). Plant Mol Biol. 2017 Oct 04;: Authors: Shinde BA, Dholakia BB, Hussain K, Panda S, Meir S, Rogachev I, Aharoni A, Giri AP, Kamble AC Abstract KEY MESSAGE: Exploration with high throughput leaf metabolomics along with functional genomics in wild tomato unreveal potential role of steroidal glyco-alkaloids and phenylpropanoids during early blight resistance. Alternaria solani severely affects tomato (Solanum lycopersicum L.) yield causing early blight (EB) disease in tropical environment. Wild relative, Solanum arcanum Peralta could be a potential source of EB resistance; however, its underlying molecular mechanism largely remains unexplored. Hence, non-targeted metabolomics was applied on resistant and susceptible S. arcanum accessions upon A. solani inoculation to unravel metabolic dynamics during different stages of disease progression. Total 2047 potential metabolite peaks (mass signals) were detected of which 681 and 684 metabolites revealed significant modulation and clear differentiation in resistant and susceptible accessions, respectively. Majority of the EB-triggered metabolic changes were active from steroidal glycol-alkaloid (SGA), lignin and flavonoid biosynthetic pathways. Further, biochemical and gene expression analyses of key enzymes from these pathways positively correlated with phenotypic variation in the S. arcanum accessions indicating their potential role in EB. Additionally, transcription factors regulating lignin biosynthesis were also up-regulated in resistant plants and electrophoretic mobility shift assay revealed sequence-specific binding of rSaWRKY1 with MYB20 promoter. Moreover, transcript accumulation of key genes from phenylpropanoid and SGA pathways along with WRKY and MYB in WRKY1 transgenic tomato lines supported above findings. Overall, this study highlights vital roles of SGAs as phytoalexins and phenylpropanoids along with lignin accumulation unrevealing possible mechanistic basis of EB resistance in wild tomato. PMID: 28980117 [PubMed - as supplied by publisher]

Metabolic regulation specific to leukemia stem cells. Rinsho Ketsueki. 2017;58(10):1818-1827 Authors: Naka K Abstract Leukemia stem cells (LSCs) are responsible for relapse of leukemia. LSCs maintain their self-renewal capacity, stemness properties, and therapeutic resistance in a manner dependent on their cell of origin and genetic alterations acquired during subsequent clonal evolution. Specific mechanisms of metabolic control and nutrient acquisition are implicated in the regulation of LSC survival. Recent advances in gene modification strategies in mice and in sophisticated metabolomics technologies are producing novel inquiries in LSC research performed in vivo. In this review, I examined our current knowledge on the roles of various metabolic pathways, including glucose metabolism, lipid oxidation, and an alternative route of amino acid and peptide supply, that support the maintenance of self-renewal capacity and therapeutic resistance in LSCs in vivo. PMID: 28978820 [PubMed - in process]

Metabolic alterations in multiple sclerosis and the impact of vitamin D supplementation. JCI Insight. 2017 Oct 05;2(19): Authors: Bhargava P, Fitzgerald KC, Calabresi PA, Mowry EM Abstract BACKGROUND: Our goal was to identify changes in the metabolome in multiple sclerosis (MS) and how vitamin D supplementation alters metabolic profiles in MS patients and healthy controls. METHODS: We applied global untargeted metabolomics to plasma from a cross-sectional cohort of age- and sex-matched MS patients and controls and a second longitudinal cohort of MS patients and healthy controls who received 5,000 IU cholecalciferol daily for 90 days. We applied partial least squares discriminant analysis, weighted correlation network analysis (WGCNA), and pathway analysis to the metabolomics data. Generalized estimating equations models were used to assess change in WGCNA-identified module scores or metabolite pathways with vitamin D supplementation. RESULTS: Utilizing multiple analytical techniques, we identified metabolic alterations in oxidative stress (γ-glutamyl amino acid, glutathione) and xenobiotic metabolism (benzoate, caffeine) in MS patients compared with healthy controls in the first cohort. In the vitamin D supplementation cohort, we identified two sets of metabolites altered differentially between MS patients and healthy controls with vitamin D supplementation. The first included markers of oxidative stress and protein oxidation (P = 0.006), while the second contained lysolipids and fatty acids (P = 0.03). CONCLUSIONS: Using metabolomics, we identified alterations in oxidative stress and xenobiotic metabolism in MS patients and subsequently demonstrated a reduction of oxidative stress markers with vitamin D supplementation in healthy controls but not in MS patients. We demonstrate the utility of metabolomics in identifying aberrant metabolic processes and in monitoring the ability of therapeutic interventions to correct these abnormalities. TRIAL REGISTRATION: ClinicalTrials.gov NCT01667796. FUNDING: This study was supported by NIH grant K23 NS067055, grants from the Race to Erase MS, the National Multiple Sclerosis Society, the American Academy of Neurology, and North American Research Committee on Multiple Sclerosis. PMID: 28978801 [PubMed - as supplied by publisher]

Disruption of glucagon receptor signaling causes hyperaminoacidemia exposing a possible liver - alpha-cell axis. Am J Physiol Endocrinol Metab. 2017 Oct 03;:ajpendo.00198.2017 Authors: Galsgaard KD, Winther-Sørensen M, Ørskov C, Kissow H, Poulsen SS, Vilstrup H, Prehn C, Adamski J, Jepsen SL, Hartmann B, Hunt J, Charron MJ, Pedersen J, Wewer Albrechtsen NJ, Holst JJ Abstract Glucagon secreted from the pancreatic alpha-cells is essential for regulation of blood glucose levels. However, glucagon may play an equally important role in the regulation of amino acid metabolism by promoting ureagenesis. We hypothesized that disruption of glucagon receptor signaling would lead to an increased plasma concentration of amino acids, which in a feedback manner stimulates the secretion of glucagon, eventually associated with compensatory proliferation of the pancreatic alpha-cells. To address this, we performed plasma profiling of glucagon receptor knockout (Gcgr(-/-)) mice and wild-type (WT) littermates using liquid chromatography mass spectrometry (LC-MS)-based metabolomics, and tissue biopsies from the pancreas were analyzed for islet hormones and by histology. A principal component analysis of the plasma metabolome from Gcgr(-/-) and WT littermates indicated amino acids as the primary metabolic component distinguishing the two groups of mice. Apart from their hyperaminoacidemia, Gcgr(-/-) mice display hyperglucagonemia, increased pancreatic content of glucagon and somatostatin (but not insulin), and alpha-cell hyperplasia and hypertrophy compared to WT littermates. Incubating cultured α-TC1.9 cells with a mixture of amino acids (Vamin 1%) for 30 minutes and for up to 48 hours led to increased glucagon concentrations (~six-fold) in the media and cell proliferation (~two-fold), respectively. In anesthetized mice, a glucagon receptor specific antagonist (Novo Nordisk 25-2648, 100 mg/kg) reduced amino acid clearance. Our data supports the notion that glucagon secretion and hepatic amino acid metabolism are linked in a close feedback loop, which operates independently of normal variations in glucose metabolism. PMID: 28978545 [PubMed - as supplied by publisher]

Tissue metabolic changes for effects of pirfenidone in rats of acute paraquat poisoning by GC-MS. Toxicol Ind Health. 2017 Jan 01;:748233717731959 Authors: Ma J, Sun F, Chen B, Tu X, Peng X, Wen C, Hu L, Wang X Abstract We developed a metabolomic method to evaluate the effect of pirfenidone on rats with acute paraquat (PQ) poisoning, through the analysis of various tissues (lung, liver, kidney, and heart), by gas chromatography-mass spectrometry (GC-MS). Thirty-eight rats were randomly divided into a control group, an acute PQ (20 mg kg(-1)) poisoning group, a pirfenidone (20 mg kg(-1)) treatment group, and a pirfenidone (40 mg kg(-1)) treatment group. Partial least squares-discriminate analysis (PLS-DA) revealed metabolic alterations in rat tissue samples from the two pirfenidone treatment groups after acute PQ poisoning. The PLS-DA 3D score chart showed that the rats in the acute PQ poisoning group were clearly distinguished from the rats in the control group. Also, the two pirfenidone treatment groups were distinguished from the acute PQ poisoning group and control group. Additionally, the pirfenidone (40 mg kg(-1)) treatment group was separated farther than the pirfenidone (20 mg kg(-1)) treatment group from the acute PQ poisoning group. Evaluation of the pathological changes in the rat tissues revealed that treatment with pirfenidone appeared to decrease pulmonary fibrosis in the acute PQ poisoning rats. The results indicate that pirfenidone induced beneficial metabolic alterations in the tissues of rats with acute PQ poisoning. Rats with acute PQ poisoning exhibited a certain reduction in biochemical indicators after treatment with pirfenidone, indicating that pirfenidone could protect liver and kidney function. Accordingly, the developed metabolomic approach proved to be useful to elucidate the effect of pirfenidone in rats of acute PQ poisoning. PMID: 28978283 [PubMed - as supplied by publisher]

Metabolomic biomarkers of pancreatic cancer: a meta-analysis study. Oncotarget. 2017 Sep 15;8(40):68899-68915 Authors: Mehta KY, Wu HJ, Menon SS, Fallah Y, Zhong X, Rizk N, Unger K, Mapstone M, Fiandaca MS, Federoff HJ, Cheema AK Abstract Pancreatic cancer (PC) is an aggressive disease with high mortality rates, however, there is no blood test for early detection and diagnosis of this disease. Several research groups have reported on metabolomics based clinical investigations to identify biomarkers of PC, however there is a lack of a centralized metabolite biomarker repository that can be used for meta-analysis and biomarker validation. Furthermore, since the incidence of PC is associated with metabolic syndrome and Type 2 diabetes mellitus (T2DM), there is a need to uncouple these common metabolic dysregulations that may otherwise diminish the clinical utility of metabolomic biosignatures. Here, we attempted to externally replicate proposed metabolite biomarkers of PC reported by several other groups in an independent group of PC subjects. Our study design included a T2DM cohort that was used as a non-cancer control and a separate cohort diagnosed with colorectal cancer (CRC), as a cancer disease control to eliminate possible generic biomarkers of cancer. We used targeted mass spectrometry for quantitation of literature-curated metabolite markers and identified a biomarker panel that discriminates between normal controls (NC) and PC patients with high accuracy. Further evaluation of our model with CRC, however, showed a drop in specificity for the PC biomarker panel. Taken together, our study underscores the need for a more robust study design for cancer biomarker studies so as to maximize the translational value and clinical implementation. PMID: 28978166 [PubMed]

Effects of the Kinase Inhibitor Sorafenib on Heart, Muscle, Liver, and Plasma Metabolism In Vivo using Non-Targeted Metabolomics Analysis. Br J Pharmacol. 2017 Oct 04;: Authors: Jensen BC, Parry TL, Huang W, Beak JY, Ilaiwy A, Bain JR, Newgard CB, Muehlbauer MJ, Patterson C, Johnson GL, Willis MS Abstract BACKGROUND AND PURPOSE: The human kinome consists of roughly 500 kinases, including 150 that have been proposed as therapeutic targets. Protein kinases regulate an array of signaling pathways that control metabolism, cell cycle progression, cell death, differentiation, and survival. It is not surprising, then, that new kinase inhibitors (KIs) developed to treat cancer, including sorafenib, also exhibit cardiotoxicity. We hypothesized that sorafenib cardiotoxicity is related to its deleterious effects on specific cardiac metabolic pathways given the critical roles of protein kinases in cardiac metabolism. EXPERIMENTAL APPROACH: FVB/N mice (10 per group) were challenged with sorafenib or vehicle control daily for two weeks. Echocardiographic assessment of the heart identified systolic dysfunction consistent with cardiotoxicity in sorafenib-treated mice compared to vehicle treated controls. Heart, skeletal muscle, liver, and plasma were flash frozen and prepped for non-targeted GC-MS metabolomics analysis. KEY RESULTS: Compared to vehicle treated controls, sorafenib-treated hearts exhibited significant alterations in 11 metabolites, including markedly altered taurine/hypotaurine metabolism (25-fold enrichment) by pathway enrichment analysis. CONCLUSIONS AND IMPLICATIONS: These studies identify alterations in taurine/hypotaurine metabolism in the hearts and skeletal muscles of mice treated with sorafenib. Interventions to rescue or prevent sorafenib-related cardiotoxicity by targeting the induced taurine/hypotaurine deficiency identified in the current study. PMID: 28977680 [PubMed - as supplied by publisher]

Metabolomic profile of arterial stiffness in aged adults. Diab Vasc Dis Res. 2017 Oct 01;:1479164117733627 Authors: Koh AS, Gao F, Liu J, Fridianto KT, Ching J, Tan RS, Wong JI, Chua SJ, Leng S, Zhong L, Keng BM, Huang FQ, Yuan JM, Koh WP, Kovalik JP Abstract BACKGROUND: Increasing arterial stiffness is an important contributor to declining cardiovascular health in ageing. Changes in whole-body fuel metabolism could be related to alterations in arterial stiffness in ageing adults. METHODS: Targeted high-performance liquid and gas chromatography mass spectrometry were used to measure 84 circulating metabolites in a group of community elderly adults ( n = 141, 58% men; mean age = 70.6 ± 11.2 years) without cardiovascular disease. In basic and adjusted models, we correlated the measured metabolites to carotid-femoral pulse wave velocity assessed by applanation tonometry. RESULTS: Age ( β = 0.10, p < 0.0001), smoking status ( β = 1.32, p = 0.02), dyslipidemia ( β = 1.22, p = 0.01), central systolic blood pressure ( β = 0.05, p < 0.0001), central mean arterial pressure ( β = 0.04, p = 0.03) and central pulse pressure ( β = 0.05, p < 0.0001) were significantly associated with pulse wave velocity. Amino acids such as histidine, methionine and valine correlated with pulse wave velocity. In multivariable models adjusted for clinical covariates, only Factor 5, comprising the medium- and long-chain dicarboxyl and hydroxyl acylcarnitines was independently associated with pulse wave velocity ( β = 0.24, p = 0.015). CONCLUSION: An upstream metabolic perturbation comprising medium- and long-chain dicarboxyl and hydroxyl acylcarnitines, likely reflecting changes in cellular fatty acid oxidation, was associated with arterial stiffness among aged adults. This advances mechanistic understanding of arterial stiffness among aged adults before clinical disease. PMID: 28976207 [PubMed - as supplied by publisher]