Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Lipid signaling wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Gene regulatory network wikipedia , lookup
Secreted frizzled-related protein 1 wikipedia , lookup
Biochemical cascade wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Metabolic network modelling wikipedia , lookup
A U G U S T feature stor y Insight into Metabolic Reprogramming in Tumor Cells A tumor cell may acquire as many as 100 mutations in the course of neoplastic initiation and progression. In our genomics centric world, we tend to associate those mutational events with alterations in signal transduction pathways which regulate cell cycle progression. C hanges in signal transduction pathways can result from activating mutations in proto-oncogenes, loss of tumor suppressor function, or over-expression of proliferating enabling gene products (e.g. tyrosine kinase receptors). In addition to the requirement to circumvent cell cycle checkpoints, proliferating tumor cells must enable mechanisms to support biosynthesis resulting in a doubling of cell mass. This requires a metabolic reprogramming directed by many of the same mutational events and altered signal transduction pathways more typically associated with cell cycle regulation. keep reading this story 2 0 1 3 I S S U E News & EVENTS Press Release: IMDEA Food and Metabolon, Inc. Announce Strategic Collaboration to Advance Nutrition-based Personalized Medicine July 9, 2013 | Read Press Release Publication makes cover and gets media attention: A Bloodspot-based Diagnostic Test for Fibromyalgia Syndrome and Related Disorders June 20, 2013 | MORE INFO Metabolomics in Pneumonia and Sepsis: an Analysis of the GenIMS Cohort Study Seymour, C. et al | Intensive Care Medicine, 2013 MORE INFO publications Cancer/Oncology Integrated Metabolite and Gene Expression Profiles Identify Lipid Biomarkers Associated with Progression of Hepatocellular Carcinoma and Patient Outcomes Budhu, A., S. Roessler, et al. | Gastroenterology, 2013 VIEW SUMMARY Phosphoglycerate Mutase 1 Coordinates Glycolysis and Biosynthesis to Promote Tumor Growth Hitosugi, T., L. Zhou, et al. | Cancer Cell, 2012 VIEW SUMMARY The Downregulation of miR-125b in Chronic Lymphocytic Leukemias Leads to Metabolic Adaptation of Cells to a Transformed State Tili, E., J.J. Michaille, et al. | Blood, 2012 VIEW SUMMARY Metabolomic Profiles Delineate Potential Role for Sarcosine in Prostate Cancer Progression Sreekumar, A., L. M. Poisson, et al. | Nature, 2009 VIEW SUMMARY The Small Molecule GMX1778 is a Potent Inhibitor of NAD+ Biosynthesis: Strategy for Enhanced Therapy in Nicotinic Acid Phosphoribosyltransferase 1-Deficient Tumors Watson, M., A. Roulston, et al. | Molecular Cell Biology, 2009 VIEW SUMMARY Inhibition of Nonsense-Mediated RNA Decay Activates Autophagy Wengrod, J. et al. | Molecular Cellular Biology, 2013 VIEW SUMMARY REFERENCES Metabolic Alterations in Mammary Cancer Prevention by Withaferin A in a Clinically Relevant Mouse Model Hahm, E. et al. | Journal of the National Cancer Institute, 2013 VIEW SUMMARY A U G U S T t h e pat h for w ard A Technical Commentary by Michael Milburn, CSO Oncology treatments have typically occupied two extreme ends of a spectrum, either consisting of radiation and chemotherapy regiments that can be regarded as a “sledgehammer” or the precise targeting of oncogenic activators via a “silver-bullet” approach. Both have produced success, but dose limiting toxicities reside on one end of this spectrum while evasiveness and resistance reside on the other. In addition to some profound success stories (e.g. vemurafenib, trastuzumab), the silver bullet approach has illuminated much about cancer biology—showing us that there is a large amount of redundancy and crosstalk in pathways such as RAF/MEK/ERK or those initiated by receptor tyrosine kinases. Heterogeneity of Tumor-Induced Gene Expression Changes in the Human Metabolic Network Hu, J. et al. | Nature Biotechnology, 2013 VIEW SUMMARY Metabolic Alterations in Lung CancerAssociated Fibroblasts Correlated with Increased Glycolytic Metabolism of the Tumor Chaudhri, V. et al. Molecular Cancer Research, 2013 VIEW SUMMARY Metabolism/Cardiovascular Disease Survival Response to Increased Ceramide Involves Metabolic Adaptation through Novel Regulators of Glycolysis and Lipolysis Nirala, N. et al. | PLoS Genetics, 2013 VIEW SUMMARY Metabolomic Signatures in Lipid-Loaded HepaRGs Reveal Pathways Involved in Steatotic Progression- Strain-Specific Red Blood Cell Storage, Metabolism, and Eicosanoid Generation in a Mouse Model Brown, M. et al. | Obesity, 2013 For a complete list of publications, please visit our website at www.metabolon.com/news/Publications.aspx. Paraoxonase-1 Deficiency is Associated with Severe Liver Steatosis in Mice Fed a High-fat High-cholesterol Diet: A Metabolomic Approach Garcia-Heredia, A. et al. Journal of Proteome Research, 2013 VIEW SUMMARY Nutrition & Consumer Goods The Role of Adipocyte XBP1 in Metabolic Regulation during Lactation Gregor, M. et al. | Cell Reports, 2013 VIEW SUMMARY Metabolomic Analysis of Sun Exposed Skin Randhawa, M. et al. Molecular BioSystems, 2013 VIEW SUMMARY Lacritin Rescues Stressed Epithelia Via Rapid FOX03 Associated Autophagy That Restores Metabolism Wang, N. et al. The Journal of Biological Chemistry, 2013 VIEW SUMMARY Infectious Disease Plasma Metabolomics Identifies Lipid Abnormalities Linked to Markers of Inflammation, Microbial Translocation, and Hepatic Function in HIV Patients Receiving Protease Inhibitors Cassol, E. et al. BMC Infectious Diseases, 2013 VIEW SUMMARY Metabolomics and Incident Hypertension Among Blacks: the Atherosclerosis Risk in Communities Study Zheng, et al. | Hypertension, 2013 VIEW SUMMARY VIEW SUMMARY Associations between Metabolomic Compounds and Incident Heart Failure among African-Americans: The Atherosclerosis Risk in Communities (ARIC) Study Zheng, Y. et al. American Journal of Epidemiology, 2013 Bioprocessing VIEW SUMMARY Application of Combined Omics Platforms to Accelerate Biomedical Discovery in Diabesity Kurland, I. et al. Annals of the NY Academy of Sciences, 2013 VIEW SUMMARY keep reading this story I S S U E publications —continued Cancer/Oncology Is it Time to Go “All-in” on Leveraging Metabolic Reprogramming of Cancer? 2 0 1 3 Pharmacological Inhibition to Examine the Role of DGAT1 in Dietary Lipid Absorption in Rodents and Humans Maciejewski, B. et al. Gastrointestinal and Liver Physiology: American Journal of Physiology, 2013 VIEW SUMMARY Glycogen Synthesis is a Required Component of the Nitrogen Stress Response in Synechococcus Elongatus PCC 7942 Hickman, J. et al. | Algal Research, 2013 VIEW SUMMARY Plant Mobilization of Lipids and Fortification of Cell Wall and Cuticle are Important in Host Defense Against Hessian Fly Khajuria, C. et al. | BMC Genomics, 2013 VIEW SUMMARY Aging Metabolomic Markers Reveal Novel Pathways of Ageing and Early Development in Human Populations Menni, C. et al. International Journal of Epidemiology, 2013 VIEW SUMMARY A bimonthly publication of: © Copyright Metabolon, Inc. 2013 +1.919.572.1711 | www.metabolon.com | [email protected] F eature stor y — continued Insight into Metabolic Reprogramming in Tumor Cells It is now appreciated that activation of oncogenes and loss of tumor suppressors contribute to a reprogramming of cellular metabolism which supports: 1) sufficient ATP and reducing equivalents to support energetic needs; 2) increases in nutrient uptake and biosynthesis; 3) survival of tumor cells in less than optimal growth conditions and 4) management of cellular redox conditions. This brief synopsis will touch on some highlights described in recent reviews [1–5] and address the role of discovery metabolic profiling in providing essential insight into cell metabolism’s critical role in tumorigenesis. Other examples of oncogene mediated metabolic reprogramming include the role of myc in increasing glutaminolysis, kras enhancement of glucose utilization and mutant isocitrate dehydrogenase modulating epigenetic programming through production of 2-hydroxyglutarate. Additional tumor suppressors whose loss impacts tumor cell metabolism include LKB, VHL and the TCA cycle enzymes fumarate hydratase and succinate dehydrogenase. Undoubtedly, many connections between tumor genomic alterations and metabolic consequences have yet to be uncovered. Activation of the PI3-Kinase/AKT pathway is one of the most common signal transduction alterations observed in tumor cells and the pathway is one of the most heavily targeted in terms of oncology drug discovery efforts. This pathway can be activated by overexpression of tyrosine growth factor receptors such as Her2 or EGFR, or through loss of PTEN function allowing constitutive activation of the pathway. AKT’s function in cell proliferation was originally linked to its ability to phosphorylate p27Kip and p21 CIP/WAF, permitting cell cycle progression. It is now clear that the PI3-Kinase/AKT pathway also contributes to: 1) increased cellular glucose levels through upregulation of glucose transporter expression and hexokinase activity, 2) increased fatty acid synthesis, through increased expression of fatty acid synthase and activation of ATP citrate lyase and 3) upregulation of protein and nucleotide synthesis through activation of the mTor complex. While PI3Kinase/AKT activation serves many other functions, activating fatty acid synthesis and protein translation are key steps toward increasing the biomass of proliferating tumor cells. The oncogenes and tumor suppressors described above represent some of the most frequently altered gene products/signaling pathways observed in tumor cells. It is now clear that oncogenes and tumor suppressors can directly regulate metabolic pathways. More importantly, we now know that measuring the resulting metabolite changes can yield a better understanding of how metabolic reprogramming might differentiate tumors, with regard to their proliferative and metastatic potential. The power of discovery metabolomics to reveal underlying signal transduction perturbations that correlate with tumor progression and patient outcomes was demonstrated in a study to identify hepatocellular (HCC) carcinoma biomarkers [7]. Discovery metabolite profiling of aggressive HCC tumors relative to normal hepatic tissue revealed that palmitic acid saturation status may be associated with clinical outcome. Palmitic acid is a substrate for stearoyl-CoA desaturase (SCD). Biological network analysis, of an integrated metabolite and transcriptomic data set, identified stearoyl-CoA desaturase as a biomarker for aggressive HCC and linked its upregulation to the PI3-kinase signaling pathway. The tumor suppressor p53 is typically viewed as a transcription factor and regulator of cell cycle progression and apoptosis. Loss of p53 is now known to affect metabolic reprogramming through upregulating glycolysis, downregulating oxidative phosphorylation and negatively regulating AKT. Shifting from oxidative phosphorylation to glycolysis as a means of generating ATP is thought to preserve carbon for biosynthetic anabolic processes of proliferating cells. An example of using global metabolomics to understand the consequences of loss of p53 is the elucidation of how phosphoglycerate mutase 1 (PGAM1) coordinates glycolysis and biosynthesis in tumor cells [6]. PGAM1 is upregulated by the loss of p53. Global metabolite profiling of lung cancer H12199 cells in which PGAM1 was stably knocked down revealed that 3-phosphoglycerate (3-PG) was elevated in knockdown cells relative to controls. Subsequent analysis demonstrated that 3-PG elevation inhibits 6-phosphogluconate dehydrogenase an enzyme that generates NADPH for use in biosynthesis and redox management. Thus, loss of p53 may enhance tumor cell biosynthesis and redox balance through upregulation of PGAM1, demonstrating the connections which can be uncovered in a discovery metabomics approach. BACK TO NEWSLETTER In the past decade it has become quite evident that oncogene signaling reprograms tumor cell metabolism to support growth and survival. Since metabolic reprogramming is a critical component of tumorigenesis, it is likely that different mutation strategies may be selected, in tumor cell populations, to accomplish similar metabolic goals. It may be advantageous to characterize tumors based on their metabolic alterations and correlate these tumor “metabolic classes” to clinical outcomes. Metabolic alterations may also contribute to de novo or acquired drug resistance, by attenuating downstream effects of therapeutics targeting specific signaling pathways [8]. Tumor cell reliance on specific oncogene or tumor suppressor-driven metabolic alterations may make them more susceptible to therapeutic agents that target those metabolic pathways. Understanding the manner in which therapeutics targeting signal transduction pathways impact tumor cell metabolism may lead to defining drug combinations that expand therapeutic windows, overcome resistance mechanisms and enable personalized cancer treatments. REFERENCES F eature stor y — R E F E R E N C E S References 1. Wallace, D.C., Mitochondria and cancer. Nat Rev Cancer, 2012. 12(10): p. 685-698. 2. Cairns, R.A., I.S. Harris, and T.W. Mak, Regulation of cancer cell metabolism. Nat Rev Cancer, 2011. 11(2): p. 85-95. 3. Ward, P.S. and C.B. Thompson, Metabolic reprogramming: a cancer hallmark even warburg did not anticipate. Cancer Cell, 2012. 21(3): p. 297-308. 4. Levine, A.J. and A.M. Puzio-Kuter, The control of the metabolic switch in cancers by oncogenes and tumor suppressor genes. Science, 2010. 330(6009): p. 1340-4. 5. Vander Heiden, M.G., Targeting cancer metabolism: a therapeutic window opens. Nat Rev Drug Discov, 2011. 10(9): p. 671-84. BACK TO NEWSLETTER 6. Hitosugi, T., et al., Phosphoglycerate mutase 1 coordinates glycolysis and biosynthesis to promote tumor growth. Cancer Cell, 2012. 22(5): p. 585-600. 7. Budhu, A., et al., Integrated metabolite and gene expression profiles identify lipid biomarkers associated with progression of hepatocellular carcinoma and patient outcomes. Gastroenterology, 2013. 144(5): p. 10661075 e1. 8. Komurov, K., et al., The glucose-deprivation network counteracts lapatinib-induced toxicity in resistant ErbB2positive breast cancer cells. Mol Syst Biol, 2012. 8: p. 596. P R E S S R E L E A S E Press Release: IMDEA Food and Metabolon, Inc. Announce Strategic Collaboration to Advance Nutrition-based Personalized Medicine Raleigh, NC – July 09, 2013 -- IMDEA Food, a Translational Research Institute from the Community of Madrid, dedicated to investigating the relationships among nutrition, food and health, and the US-based company Metabolon Inc., the pioneering leader in the field of metabolomics and molecular diagnostics serving the pharmaceutical and food industries, today announced an ambitious collaboration program. The agreement, signed today in Madrid by Dr. John Ryals, President and CEO of Metabolon, and Dr. Guillermo Reglero, Director of IMDEA Food, establishes the framework for future strategic projects aimed to develop functional foods and diagnostic tools. Of particular interest is the prevention of prevalent chronic diseases with high societal impact, such as cardiovascular disease, cancer, obesity and neurological diseases, which are highly dependent on understanding food science and nutritional impact. To achieve this goal, individual in-depth studies to characterize the molecular mechanisms underlying the health benefits of foods and food components are needed. Scientists from IMDEA Food and Metabolon have met in IMDEA Food’s new headquarters located in Madrid to define the lines of common interest and greatest priority and to launch the first of a series of studies aimed at defining the molecular basis of action of key food ingredients. Dr. Steve Watkins, Chief Technology Officer, Metabolon commented, “Collaborative studies with IMDEA will employ the combined resources and expertise of our organizations to identify appropriate biomarkers of disease risk and prevention and to monitor biological impact of nutritional components in foods. This strategic collaboration is pivotal to advancing our understanding of nutrition’s influence on health and disease.” About Metabolon: Metabolon, Inc. is the world leader in the field of metabolomics by pioneering and patenting the industry’s leading biochemical biomarker discovery and profiling platform. It has developed the technology to quickly identify and measure all of the biochemicals in a biological sample through its proprietary global processing method. Quantose™ is the first diagnostic test discovered by Metabolon using its technology. Metabolon has a broad pipeline of diagnostic products in the fields of obesity-related conditions and cancer. Metabolon’s technology expertise is being embraced by a wide range of pharmaceutical, biotechnology, food and agricultural companies. Metabolytics, its biomarker discovery and analysis business, has completed over 2,500 client studies with more than 500 customers. For more information about Metabolon, please contact Matt Zaske at [email protected], 919-5952200 or visit www.metabolon.com. “These studies promise to lead toward an efficient decrease of morbimortality due to chronic degenerative diseases and a better quality of life. IMDEA Food and Metabolon will combine their knowledge to advance towards this objective. A combined functional genomics and metabolomics approach involving complementary technologies and multidisciplinary expertise is paramount to achieve the scientific rigor and level of evidence required to bring nutrition-based personalized medicine to the public with the final objective of living longer and healthier”, commented Prof. Jose Ordovas of Tufts University, a worldrenowned pioneer in nutirgenomics. Prof. Ordovas serves as the Media Contact: Senior Scientist and Director for the Nutrition and Genomics Mackenzie Mills, Account Director, SpecOps Communications Laboratory and as the Chair of the Functional Genomics Core of 212.518.7721 Ph. | 913.558.2492 Cell the Jean Mayer USDA Human Nutrition Research Center on Aging www.SpecOpsComm.com | @SpecOpsComm at Tufts University. Since its inception in 2007 Prof. Ordovas has been Chairman of the Board and Scientific Director of IMDEA Food. The IMDEA Food Institute carries out human nutrigenomic studies, which are reviewed by a Research Ethical Committee, on its platform comprised of common services for genomics, biostatistics, bioinformatics and nutritional counseling. Metabolon is the world leader in metabolomic analysis of complex biological samples and has made major contributions to the discovery of biomarkers and biochemical pathways associated with nutrients and drugs, and which have led to the development of unique diagnostic tools. BACK TO NEWSLETTER A Bloodspot-based Diagnostic Test for Fibromyalgia Syndrome and Related Disorders Hackshaw, K. | Analyst, 2013 Abstract The aim of this study was to investigate the ability of a rapid biomarker-based method for diagnosis of fibromyalgia syndrome (FM) using mid-infrared microspectroscopy (IRMS) to differentiate patients with FM from those with osteoarthritis (OA) and rheumatoid arthritis (RA), and to identify molecular species associated with the spectral patterns. Under IRB approval, blood samples were collected from patients diagnosed with FM (n=14), RA (n=15), or OA (n=12). Samples were prepared, placed onto a highly reflective slide, and spectra were collected using IRMS. Spectra were analyzed using multivariate statistical modeling to differentiate groups. Aliquots of samples also were subjected to metabolomic analysis. IRMS separated subjects into classes based on spectral information with no misclassifications among FM and RA or OA patients. Interclass distances of 15.4 (FM vs. RA), 14.7 (FM vs. OA) and 2.5 (RA vs. OA) among subjects, demonstrating the ability of IRMS to achieve reliable resolution of unique spectral patterns specific to FM. Metabolomic analysis revealed that RA and OA groups were metabolically similar, whereas biochemical differences were identified in the FM that were quite distinctive from those found in the other two groups. Both IRMS and metabolomic analysis identified changes in tryptophan catabolism pathway that differentiated patients with FM from those with RA or OA. For more information, visit here. BACK TO NEWSLETTER Metabolics in Pneumonia and Sepsis: an Analysis of the GenIMS Cohort Study Seymour, C. et al. | Intensive Care Medicine, 2013 Abstract Purpose: To determine the global metabolomic profile as measured in circulating plasma from surviving and non-surviving patients with community-acquired pneumonia (CAP) and sepsis. Methods: Random, outcome-stratified case–control sample from a prospective study of 1,895 patients hospitalized with CAP and sepsis. Cases (n=15) were adults who died before 90 days, and controls (n=15) were adults who survived, matched on demographics, infection type, and procalcitonin. We determined the global metabolomic profile in the first emergency department blood sample using non-targeted mass-spectrometry. We derived metabolitebased prognostic models for 90-day mortality. We determined if metabolites stimulated cytokine production by differentiated Thp1 monocytes in vitro, and validated metabolite profiles in mouse liver and kidney homogenates at 8 h in cecal ligation and puncture (CLP) sepsis. Results: We identified 423 small molecules, of which the relative levels of 70 (17 %) were different between survivors and non-survivors (p B 0.05). Broad differences were present in pathways of oxidative stress, bile acid metabolism, and stress response. Metabolite-based prognostic models for 90-day survival performed modestly (AUC=0.67, 95 % CI 0.48, 0.81). Five nucleic acid metabolites were greater in non-Intensive Care Med DOI 10.1007/s00134013-2935-7 ORIGINAL survivors (p B 0.05). Of these, pseudouridine increased monocyte expression of TNFa and IL1b versus control (p\0.05). Pseudouridine was also increased in liver and kidney homogenates from CLP mice versus sham (p\0.05 for both). Conclusions: Although replication is required, we show the global metabolomic profile in plasma broadly differs between survivors and nonsurvivors of CAP and sepsis. Metabolite-based prognostic models had modest performance, though metabolites of oxidative stress may act as putative damage-associated molecular patterns. BACK TO NEWSLETTER For more information, visit here. Integrated Metabolite and Gene Expression Profiles Identify Lipid Biomarkers Associated with Progression of Hepatocellular Carcinoma and Patient Outcomes Budhu al. | Gastroenterology, 2013 Metabolon results led to: • Biomarkers of outcome and aggressiveness for hepatocellular carcinoma (HCC) • Potential new target for HCC (stearoyl-CoA-desaturase (SCD)) • Confirmation that the addition of metabolomics to gene expression data provides clarity Key metabolomic observations: • A SCD-related lipid signature with aggressive HCC Synopsis Hepatocellular carcinoma (HCC) is a common and aggressive malignancy with a poor prognosis. Thus, investigators sought to understand the molecular networks of aggressive HCC to more readily identify aggressive HCC and find new targets and biomarkers in HCC patient tumor biopsy. Integration of gene expression and metabolomic data identified a lipogenic network that involves stearoyl-CoA-desaturase (SCD) and its substrate and product (palmitate and palmitoleate). SCD was independently associated with survival times and tumor recurrence in the test and validation sets. Further, palmitoleate was increased in aggressive HCCs and increased migration and invasion of cultured HCC cells. Suppressing SCD with siRNA decreased cell migration and colony formation in culture and reduced tumorigenicity in mice. Thus, the imbalance of lipogenic components and pathways, centering on SCD, may function as key biomarkers for aggressive cancer and enable the strategic development of clinically relevant therapies. BACK TO NEWSLETTER Phosphoglycerate Mutase | Coordinates Glycolysis and Biosynthesis to Promote Tumor Growth Hitosugi et. al | Cancer Cell, 2012 Metabolon results led to: • Discovery of a glycolysis enzyme critical for coordinating glucose utilization for energy production vs. anabolic biosynthesis in tumor cells • Discovery that small molecule inhibition of that enzyme effectively reduced tumor size in pre-clinical models, and that effect translated to primary cell lines from human cancer patients Key metabolomic observations: • PGAM1 knockdown (gene or small molecule) altered levels of the substrate and product of the enzyme. Those metabolites regulate other pathways through competitive inhibition. • PGAM1 coordinates regulation of glycolysis and the PPP, which generates substrates for proliferation. Synopsis Cancer cells have long been known increase glucose uptake to generate building blocks for cell proliferation. Understanding how cancer cells divert glucose to anabolic pathways may reveal new drug targets. This study with several cancer cell types identified the glycolysis enzyme PGAM1 as a critical branch point for diverting glucose into the pentose phosphate pathway (PPP), which generates anabolic precursors including NADPH and nucleotides. This discovery of metabolic remodeling effects of PGAM1 led to several additional discoveries: (1) PGAM1 knockdown reduced tumor mass in a mouse xenograft model system. (2) The PGAM1 substrate 3-phosphoglycerate is a competitive inhibitor of the PPP enzyme 6-phosphogluconate dehydrogenase, and this connection underlies the coordinated regulation of glycolysis and anabolic biosynthesis. (3) Results were translated to human studies where a new PGAM1 inhibitor decreased proliferation of primary leukemia cells from 7 of 8 leukemia patients, suggesting PGAM1 is a promising target for combating human cancers. BACK TO NEWSLETTER The Downregulation of miR-125b in Chronic Lymphocytic Leukemias Leads to Metabolic Adaptation of Cells to a Transformed State Tili, E., J.J. Michaille, et al. | Blood, 2012 Metabolon results led to: • Identification of a master metabolic regulator that is defective in the transformed state • Biomarkers for segregating indolent versus aggressive forms of chronic lymphocytic leukemia (CLL) • Potential therapeutic targets Key metabolomic observations: • A clear signature of Warburg metabolism • An increase in growth and survival promoting polyamines • Increased lipogenesis Synopsis miR-125b is one of the most conserved miRNAs and maps to a chromosomal epicenter for deletions in chronic lymphocytic leukemia (CLL). Thus, posing the question of whether miR-125b has a potential role in CLL? Investigators used gene expression profiling and metabolomicsto reveal that miR-125b is underexpressed in isolated lymphocytes from CLL subjects resulting in a profound change in the metabolic state featuring “Warburg” metabolism, elevation in growth promoting polyamines, and a lipogenic signature. Metabolites distinct from these could differentiate indolent from aggressive forms of CLL, suggesting the possibility of using these markers to identify at risk subjects. Finally, the identification of miR-125b as a master regulator and a driver for a cancer metabolic phenotype offers the possibility of targeting key metabolic pathways that are activated by the under-expression of this metabolic regulator. BACK TO NEWSLETTER Metabolomic Profiles Delineate Potential Role for Sarcosine in Prostate Cancer Progression Sreekumar, A., L. M. Poisson, et al. | Nature, 2009 Metabolon results led to: • Identification of a biomarker of cancer progression • Discovery of a “oncometabolite” that participates in neoplastic progression • Candidate drug targets for prostate cancer Key metabolomic observations: • Sarcosine was identified as a metabolite that tracked with prostate cancer progression • Increasing sarcosine levels in a benign prostate cell line increased cell invasiveness • Decreasing sarcosine levels in an aggressive prostate cancer cell line decreased cell invasiveness Synopsis Current screening methods for diagnosing prostate cancer provide little insight into cancer aggressivity. Among more than 600 metabolites measured in human prostate tissues with metabolomics, sarcosine (N-methyl glycine) was identified as the metabolite that tracked most robustly with cancer progression. This biomarker was further validated with an independent sample cohort and targeted assay. Increasing levels of sarcosine through direct addition, or manipulation of regulatory enzymes, conferred invasive properties to a benign prostate cell line. Together these results suggest that sarcosine participates in neoplastic transformation and that sarcosine’s proximal regulatory enzymes could be targeted to combat cancer progression. Additionally, these results indicate metabolite panels can be developed to distinguish slow-growing from aggressive cancers and inform clinicians and patients in selecting a treatment strategy. BACK TO NEWSLETTER The Small Molecule GMX1778 is a Potent Inhibitor of NAD+ Biosynthesis: Strategy for Enhanced Therapy in Nicotinic Acid Phosphoribosyltransferase 1-Deficient Tumors Watson et al. | Molecular and Cellular Biology, 2009 Metabolon results led to: • Determination of the mechanism of action of an anti-cancer drug • Identification of a new therapeutic strategy to specifically target cancer cells and spare healthy cells Key metabolomic observations: • The cofactor NAD+ was greatly depleted in drug-treated cells • An enzyme involved in NAD+ salvage as the molecular target of the drug • Tumor cells dependent on this NAD+ salvage pathway are more sensitive to the drug than healthy cells that can synthesize NAD+ de novo Synopsis The long-standing hypothesis that anti-cancer effects of GMX1778 resulted from NF-kB inhibition were challenged by metabolomics results showing that GMX1778 actually perturbed an entirely different pathway, depleting the cofactor NAD+ from cells early after drug addition. This observation allowed for straight-forward validation experiments that unambiguously identified an enzyme required for NAD+ salvage (nicotinamide phosphoribosyltransferase, NAMPRT) as the direct target of the drug, and showed that effects of the drug on NF-kB activity and cancer cell viability were downstream of NAD+ salvage inhibition. Identification of NAMPRT as the true drug target led to a new therapeutic strategy in glioblastomas and neuroblastomas. These tumors depend on NAD+ salvage because they lack enzymes necessary for de novo NAD+ synthesis, suggesting that addition of niacin to be utilized by healthy cells could increase the therapeutic window of this anti-cancer drug. BACK TO NEWSLETTER Inhibition of Nonsense-Mediated RNA Decay Activates Autophagy Wengrod, J. et al. | Molecular Cell Biology, 2013 Abstract Nonsense mediated RNA decay (NMD) is a mRNA surveillance mechanism which rapidly degrades select cytoplasmic mRNAs. We and others have shown that NMD is a dynamically regulated process inhibited by amino acid deprivation, hypoxia, and other cellular stresses commonly generated by the tumor microenvironment. This inhibition of NMD can result in the accumulation of misfolded, mutated, and aggregated proteins, but how cells adapt to these aberrant proteins is unknown. Here we demonstrate that the inhibition of NMD activates autophagy, an established protein surveillance mechanism, both in vitro and in vivo. Conversely, the hyperactivation of NMD blunts the induction of autophagy in response to a variety of cellular stresses. The regulation of autophagy by NMD is due, in part, to stabilization of the documented NMD target ATF-4. NMD inhibition increases intracellular amino acids, a hallmark of autophagy, and the concomitant inhibition of autophagy and NMD, either molecularly or pharmacologically, leads to synergistic cell death. Together these studies indicate that autophagy is an adaptive response to NMD inhibition, and uncover a novel relationship between a mRNA surveillance system and a protein surveillance system with important implications for the treatment of cancer. BACK TO NEWSLETTER Metabolic Alterations in Mammary Cancer Prevention by Withaferin A in a Clinically Relevant Mouse Model Hahm, E. et al. | Journal of the National Cancer Institute, 2013 Abstract Background: Efficacy of withaferin A (WA), an Ayurvedic medicine constituent, for prevention of mammary cancer and its associated mechanisms were investigated using mouse mammary tumor virus–neu (MMTV-neu) transgenic model. Methods: Incidence and burden of mammary cancer and pulmonary metastasis were scored in female MMTV-neu mice after 28 weeks of intraperitoneal administration with 100 μg WA (three times/week) (n=32) or vehicle (n=29). Mechanisms underlying mammary cancer prevention by WA were investigated by determination of tumor cell proliferation, apoptosis, metabolomics, and proteomics using plasma and/or tumor tissues. Spectrophotometric assays were performed to determine activities of complex III and complex IV. All statistical tests were two-sided. Results: WA administration resulted in a statistically significant decrease in macroscopic mammary tumor size, microscopic mammary tumor area, and the incidence of pulmonary metastasis. For example, the mean area of invasive cancer was lower by 95.14% in the WA treatment group compared with the control group (mean=3.10 vs 63.77 mm2, respectively; difference=–60.67 mm2; 95% confidence interval=–122.50 to 1.13 mm2; P=.0536). Mammary cancer prevention by WA treatment was associated with increased apoptosis, inhibition of complex III activity, and reduced levels of glycolysis intermediates. Proteomics confirmed downregulation of many glycolysis-related proteins in the tumor of WA-treated mice compared with control, including M2-type pyruvate kinase, phosphoglycerate kinase, and fructose-bisphosphate aldolase A isoform 2. Conclusions: This study reveals suppression of glycolysis in WA-mediated mammary cancer prevention in a clinically relevant mouse model. BACK TO NEWSLETTER t h e pat h for w ard — continued Is it Time to Go “All-in” on Leveraging Metabolic Reprogramming of Cancer? A Technical Commentary by Michael Milburn, CSO Lack of efficacy or acquired resistance to therapies can result from upregulation of pathway components or activation of parallel signaling pathways. Hence, these therapies often require combinations to drive efficacy and to reduce the potential for resistance. Ideally, the combination agent should be highly specific to a characteristic of the particular cancer or all cancers in general. As our feature article outlines, one of the most promising exploitable characteristics, common to almost all cancers, is metabolic reprogramming. As Dr. Stirdivant details therein, nearly all oncogenic roads are revealing themselves to enable the anabolic mission of the tumor. These include classic driver substrate combinations such as Myc/glutamine, Akt/glucose as well mTOR/amino acid and nucleotide metabolism. In addition, a host of new metabolic targets are emerging that all have the common feature of supporting the anabolic mission of the cell (e.g. PGAM1, IDH1, SCD1). Hence, a clear opportunity has emerged for determining the metabolic features of a given tumor (metabotyping) in combination with the genotype (see the June newsletter for additional detail on metabotyping). The idea is to devise targeted efficacious combinations based on an individual genotype and metabotype, where the signaling component is analogous to a water spigot and the metabolic target the hose outlet. Not only would a tumor be precisely targeted from two vantage points, but this dual-targeted therapy would decrease the chances of drug resistance arising. Despite the above findings, the movement into taking advantage of this information has been modest. Ushering in many of these discoveries linking oncogenes to metabolic reprogramming and uncovering the full extent of metabolic reprogramming (hence targets and biomarkers) is traditional scientific discipline and rigor and the field of metabolomics. BACK TO NEWSLETTER We have seen firsthand how discoveries in metabolomics and combination therapies may be realized in work involving the NAD biosynthesis pathway (a key metabolite in metabolic reprogramming). Several years ago, we collaborated with GeminX pharmaceuticals to reveal that a development compound of unknown mechanism was targeting NAMPT (the rate limiting enzyme in NAD biosynthesis). Since then, several companies have initiated programs to pursue this target and many publications have been produced, but one recent work by Cagnetta and colleagues in Blood (2013 Jul 3, Epub ahead of print) provides a striking example of how metabolic targets may be successfully combined with a targeted therapy to enhance activity and overcome resistance. Metabotyping of cells from bortezomib resistant patients revealed higher expression of NAMPT. Remarkably, when low doses of a NAMPT inhibitor were combined with the bortezomib, a synergistic effect and reduced resistance resulted. We imagine that should researchers and clinicians move more aggressively into this space, many more success stories like this will result. Hence, although there is more work to be done to establish clinical utility of these new metabolic targets (of course, many of today’s chemotherapeutic agents target metabolism), there is increasing confidence that metabolite biomarker-driven tumor metabolic classification combined with therapeutics attacking key metabolic nodes, may yield the tumor selectivity and durability of response that has been so elusive with targeted therapies. Metabolytics combined in a complementary fashion with oncogenotyping will be a key component in selecting the proper customized treatment options that will optimize success rates in the new era of personalized cancer therapy. As details in the feature article demonstrate, the science is making a compelling case for optimism. Heterogeneity of Tumor-Induced Gene Expression Changes in the Human Metabolic Network Hu, J. et al. | Nature Biotechnology, 2013 Abstract Reprogramming of cellular metabolism is an emerging hallmark of neoplastic transformation. However, it is not known how the expression of metabolic genes in tumors differs from that in normal tissues, or whether different tumor types exhibit similar metabolic changes. Here we compare expression patterns of metabolic genes across 22 diverse types of human tumors. Overall, the metabolic gene expression program in tumors is similar to that in the corresponding normal tissues. Although expression changes of some metabolic pathways (e.g., upregulation of nucleotide biosynthesis and glycolysis) are frequently observed across tumors, expression changes of other pathways (e.g., oxidative phosphorylation) are very heterogeneous. Our analysis also suggests that the expression changes of some metabolic genes (e.g., isocitrate dehydrogenase and fumarate hydratase) may enhance or mimic the effects of recurrent mutations in tumors. On the level of individual biochemical reactions, many hundreds of metabolic isoenzymes show significant and tumor-specific expression changes. These isoenzymes are potential targets for anticancer therapy. BACK TO NEWSLETTER Metabolic Alterations in Lung Cancer-Associated Fibroblasts Correlated with Increased Glycolytic Metabolism of the Tumor Chaudhri, V.K., et al. | Molecular Cancer Research, 2013 Metabolon results led to: • That autophagy is a distinguishing feature of cancer associated fibroblasts (CAFs) • Greater understanding of the tumor microenvironment • A template for how to investigate tumor metabolism in its isolated parts (i.e. stroma vs. epithelium) Key metabolomic observations: • Marker of protein breakdown (dipeptides) were increased in CAFs Synopsis There is significant appreciation that cancer cells undergo metabolic reprogramming but there is far less understanding of the metabolic phenotypes of the other cell types comprising the ”ecosystem” of the microenvironment. As a first step, investigators sought to derive the metabolic profile of primary human lung tumor cancer-associated fibroblast lines (CAFs) compared to “normal” fibroblast lines (NFs) generated from adjacent non-neoplastic lung tissue. Dipeptides were the clearest signature segregating the CAFs from the most glycolytic tumors and led to the hypothesis that CAFs may engage autophagy more than NFs. Follow-up experiments confirmed this hypothesis. These distinctions in metabolic features in the cells comprising the microenvironment may also assist in devising next generation combination therapies that target aspects of both the cancer cell and the stroma. BACK TO NEWSLETTER Survival Response to Increased Ceramide Involves Metabolic Adaptation through Novel Regulators of Glycolysis and Lipolysis Nirala, N. et al. | PLoS Genetics, 2013 Abstract The sphingolipid ceramide elicits several stress responses, however, organisms survive despite increased ceramide but how they do so is poorly understood. We demonstrate here that the AKT/FOXO pathway regulates survival in increased ceramide environment by metabolic adaptation involving changes in glycolysis and lipolysis through novel downstream targets. We show that ceramide kinase mutants accumulate ceramide and this leads to reduction in energy levels due to compromised oxidative phosphorylation. Mutants show increased activation of Akt and a consequent decrease in FOXO levels. These changes lead to enhanced glycolysis by upregulating the activity of phosphoglyceromutase, enolase, pyruvate kinase, and lactate dehydrogenase to provide energy. A second major consequence of AKT/FOXO reprogramming in the mutants is the increased mobilization of lipid from the gut through novel lipase targets, CG8093 and CG6277 for energy contribution. Ubiquitous reduction of these targets by knockdown experiments results in semi or total lethality of the mutants, demonstrating the importance of activating them. The efficiency of these adaptive mechanisms decreases with age and leads to reduction in adult life span of the mutants. In particular, mutants develop cardiac dysfunction with age, likely reflecting the high energy requirement of a well-functioning heart. The lipases also regulate physiological triacylglycerol homeostasis and are important for energy metabolism since midgut specific reduction of them in wild type flies results in increased sensitivity to starvation and accumulation of triglycerides leading to cardiac defects. The central findings of increased AKT activation, decreased FOXO level and activation of phosphoglyceromutase and pyruvate kinase are also observed in mice heterozygous for ceramide transfer protein suggesting a conserved role of this pathway in mammals. These data reveal novel glycolytic and non-autonomous lipolytic pathways in response to increased ceramide for sustenance of high energy demanding organ functions like the heart. BACK TO NEWSLETTER Metabolomic Signatures in Lipid-Loaded HepaRGs Reveal Pathways Involved in Steatotic Progression Strain-Specific Red Blood Cell Storage, Metabolism, and Eicosanoid Generation in a Mouse Model Brown, M. et al. | Obesity, 2013 Abstract Objectives: A spectrum of disorders including simple steatosis, nonalcoholic steatohepatitis, fibrosis, and cirrhosis is described by nonalcoholic fatty liver disease (NAFLD). With the increased prevalence of obesity, and consequently NAFLD, there is a need for novel therapeutics in this area. To facilitate this effort, a cellular model of hepatic steatosis was developed using HepaRG cells and the resulting biochemical alterations were determined. Design & Methods: Using global metabolomic profiling, by means of a novel metabolite extraction procedure, the metabolic profiles in response to the saturated fatty acid palmitate, and a mixture of saturated and unsaturated fatty acids, palmitate and oleate (1:2) were examined. Results: We observed elevated levels of the branched chain amino acids, tricarboxylic acid cycle intermediates, sphingosine and acylcarnitines, and reduced levels of carnitine in the steatotic HepaRG model with both palmitate and palmitate:oleate treatments. In addition, elevated levels of diacylglycerols and monoacylglycerols as well as altered bile acid metabolism were selectively displayed by palmitateinduced steatotic cells. Conclusions: Biochemical changes in pathways important in the transition to hepatic steatosis including insulin resistance, altered mitochondrial metabolism, and oxidative stress are revealed by this global metabolomic approach. Moreover, the utility of this in vitro model for investigating the mechanisms of steatotic progression, insulin resistance, and lipotoxicity in NAFLD was demonstrated. BACK TO NEWSLETTER Metabolomics and Incident Hypertension Among Blacks: the Atherosclerosis Risk in Communities Study Zheng, Y. et al. | Hypertension, 2013 Abstract Development of hypertension is influenced by genes, environmental effects, and their interactions, and the human metabolome is a measurable manifestation of gene–environment interaction. We explored the metabolomic antecedents of developing incident hypertension in a sample of blacks, a population with a high prevalence of hypertension and its comorbidities. We examined 896 black normotensives (565 women; aged, 45–64 years) from the Atherosclerosis Risk in Communities study, whose metabolome was measured in serum collected at the baseline examination and analyzed by high-throughput methods. The analyses presented here focus on 204 stably measured metabolites during a period of 4 to 6 weeks. Weibull parametric models considering interval censored data were used to assess the hazard ratio for incident hypertension. We used a modified Bonferroni correction accounting for the correlations among metabolites to define a threshold for statistical significance (P<3.9×10–4). During 10 years of follow-up, 38% of baseline normotensives developed hypertension (n=344). With adjustment for traditional risk factors and estimated glomerular filtration rate, each +1SD difference in baseline 4-hydroxyhippurate, a product of gut microbial fermentation, was associated with 17% higher risk of hypertension (P=2.5×10–4), which remained significant after adjusting for both baseline systolic and diastolic blood pressure (P=3.8×10–4). After principal component analyses, a sex steroids pattern was significantly associated with risk of incident hypertension (highest versus lowest quintile hazard ratio, 1.72; 95% confidence interval, 1.05–2.82; P for trend, 0.03), and stratified analyses suggested that this association was consistent in both sexes. Metabolomic analyses identify novel pathways in the pathogenesis of hypertension. BACK TO NEWSLETTER Associations between Metabolomic Compounds and Incident Heart Failure among African Americans: The Atherosclerosis Risk in Communities (ARIC) Study Zheng, Y. et al. | American Journal of Epidemiology, 2013 Abstract Heart failure (HF) is more prevalent among African-Americans. Metabolomic studies among African-Americans may efficiently identify novel biomarkers of HF. We used untargeted methods to measure 204 stable serum metabolites and evaluate their association with incident HF hospitalization (N=276) after a median follow-up of 20 years (from 1987 to 2008) using Cox regression in 1,744 African-Americans from the Jackson, MS field center of the Atherosclerosis Risk in Communities Study, aged 45–64 years and without HF at baseline. After adjusting for established risk factors, 16 metabolites (6 named with known and 10 unnamed with unknown structural identity; the latter denoted X-12345) were associated with incident HF (statistical significance based on a modified Bonferroni procedure<0.0004). Of the six named metabolites, four are involved in amino acid metabolism; one (pro-hydroxy-pro) is a dipeptide; and one (erythritol) is a sugar alcohol. After additional adjustment for kidney function, two metabolites remained associated with incident HF (X-11308, hazard ratio (HR)=0.75, 95% confidence interval (95% CI): 0.65, 0.86; X-11787, HR=1.23, 95% CI: 1.10, 1.37). Further structural analysis revealed X-11308 to be a dihydroxy docosatrienoic acid, and X-11787 an isoform of either hydroxy-leucine or hydroxy-isoleucine. Our metabolomic analysis revealed novel biomarkers associated with incident HF independently of traditional risk factors. expression changes. These isoenzymes are potential targets for anticancer therapy. BACK TO NEWSLETTER Application of Combined ‘Omics Platforms to Accelerate Biomedical Discovery in Diabesity Kurland, I. et al. | Annals of the NY Academy of Sciences, 2013 Abstract Diabesity has become a popular term to describe the specific form of diabetes that develops late in life and is associated with obesity. While there is a correlation between diabetes and obesity, the association is not universally predictive. Defining the metabolic characteristics of obesity that lead to diabetes, and how obese individuals who develop diabetes different from those who do not, are important goals. The use of large-scale omics analyses (e.g., metabolomic, proteomic, transcriptomic, and lipidomic) of diabetes and obesity may help to identify new targets to treat these conditions. This report discusses how various types of omics data can be integrated to shed light on the changes in metabolism that occur in obesity and diabetes. BACK TO NEWSLETTER Pharmacological Inhibition to Examine the Role of DGAT1 in Dietary Lipid Absorption in Rodents and Humans Maciejewskiet al. | Gastrointestinal and Liver Physiology: American Journal of Physiology,, 2013 Metabolon results led to: • Improved understanding of the full-spectrum of changes induced by DGAT inhibition • Translatable pathways, markers and changes from rodent to human Key metabolomic observations: • An elevation in polyunsaturated fatty acids (PUFA) within triglycerides (TG) Synopsis Elevated plasma triglycerides (TG) and free fatty acids (FFA) are implicated in the pathogenesis of metabolic diseases such as type 2 diabetes (T2DM) and cardiovascular disease. Acyl-CoA:diacylglycerolacyltransferase1 (DGAT1) is being pursued as a therapeutic target for diseases of elevated lipids. To more completely elucidate the full spectrum of metabolic changes, adosing study using a selective inhibitor of DGAT1 was performed on rats and humans. Striking translatability was observed in the overall effects of inhibition of TG absorption and lipidomicanalysis revealed an unexpected enrichment of polyunsaturated fatty acids (PUFA) within the TG class. The increase in PUFA may have benefits for decreasing the risk of coronary artery disease, insulin resistance, dyslipidemia and hypertension. Collectively, the results suggest that inhibition of DGAT1 could have the potential to be a pharmacological alternative to gastric bypass surgery or for T2DM and provides new insights for the impact of inhibition of DGAT1. BACK TO NEWSLETTER Paraoxonase-1 Deficiency is Associated with Severe Liver Steatosis in Mice Fed a High-fat High-cholesterol Diet: A Metabolomic Approach Garcia-Heredia, A. et al. | Journal of Proteome Research, 2013 Abstract Oxidative stress is a determinant of liver steatosis and the progression to more severe forms of disease. The present study investigated the effect of paraoxonase-1 (PON1) deficiency on histological alterations and hepatic metabolism in mice fed a high-fat high-cholesterol diet. We performed nontargeted metabolomics on liver tissues from 8 male PON1-deficient mice and 8 wild-type animals fed a high-fat, high-cholesterol diet for 22 weeks. We also measured 8-oxo-20-deoxyguanosine, reduced and oxidized glutathione, malondialdehyde, 8-isoprostanes and protein carbonyl concentrations. Results indicated lipid droplets in 14.5% of the hepatocytes of wild-type mice and in 83.3% of the PON1-deficient animals (P < 0.001). The metabolomic assay included 322 biochemical compounds, 169 of which were significantly decreased and 16 increased in PON1-deficient mice. There were significant increases in lipid peroxide concentrations and oxidative stress markers. We also found decreased glycolysis and the Krebs cycle. The urea cycle was decreased, and the pyrimidine cycle had a significant increase in orotate. The pathways of triglyceride and phospholipid synthesis were significantly increased. We conclude that PON1 deficiency is associated with oxidative stress and metabolic alterations leading to steatosis in the livers of mice receiving a high-fat high-cholesterol diet. BACK TO NEWSLETTER The Role of Adipocyte XBP1 in Metabolic Regulation during Lactation Gregor, M. et al. | Cell Reports, 2013 Abstract The adipocyte is central to organismal metabolism and exhibits significant functional and morphological plasticity during its formation and lifespan. Remarkable transformations of this cell occur during obesity and lactation, and thus it is essential to gain a better understanding of adipocyte function in these two metabolic processes. Considering the critical importance of the cellular organelle endoplasmic reticulum (ER) in adapting to fluctuations in synthetic processes, we explored the role of XBP1, a central regulator of ER adaptive responses, in adipocyte formation and function. Unexpectedly, deletion of adipocyte-XBP1 in vivo in mice (XBP1DAd) had no effect on adipocyte formation or on systemic homeostatic metabolism in mice fed a a regular or high-fat diet. However, during lactation, XBP1DAd dams displayed increased adiposity, decreased milk production, and decreased litter growth as compared with control dams. Moreover, we demonstrate that XBP1 is regulated during lactation and responds to prolactin to alter lipogenic gene expression. These results demonstrate a role for adipocyte-XBP1 in the regulation of lactational metabolism. BACK TO NEWSLETTER Metabolic Analysis of Sun Exposed Skin Randhawa, M. et al. | Molecular BioSystems, 2013 Metabolon results led to: • Novel mechanistic insights for photoaging • Biomarkers of photoaging • Treatment strategies for skin care Key metabolomic observations: • A total of 341 metabolites were detected from skin biopsies and 147 were significantly altered • Among the significantly changed metabolites were glycolytic, beta-oxidation and oxidative stress markers Synopsis The ability to slow, reverse, or protect sun-exposed skin from the effects of photoaging is limited by the understanding of the underlying mechanisms that disrupt skin architecture and the skin permeability barrier. Thus investigators at Johnson and Johnson sought to derive a deeper understanding and biomarkers that could be used to monitor efficacy by performing metabolomics on skin biopsy samples. Diverse metabolites (341) were detected in the samples and 147 were significantly different between normal and sun-exposed samples. In addition to validation of expected oxidative stress markers, many novel biomarkers and targets were identified. Among these were metabolites that produced a metabolic model for the cascade of derangements induced by sun-exposure. The results demonstrate that skin metabolomics is a promising approach for skin researchers, product developers, and for discovering efficacy biomarkers that, given the conservation of metabolites, are likely to translate into in vitro models. Notably, this approach could be markedly extended through the addition of a lipidomics analysis. BACK TO NEWSLETTER Lacritin Rescues Stressed Epithelia Via Rapid FOX03 Associated Autophagy That Restores Metabolism Wang, N. et al. | The Journal of Biological Chemistry, 2013 Abstract Homeostasis is essential for cell survival. Yet, homeostatic regulation of surface epithelia is poorly understood. The eye surface, lacking the cornified barrier of skin, provides an excellent model. Tears cover the surface of the eye, and are deficient in dry eye, the most common eye disease affecting at least 5% of the worlds population. Only a tiny fraction of the tear proteome appears to be affected, including lacritin, an epithelial-selective mitogen that promotes basal tearing when topically applied to rabbit eyes. Here we discover that homeostasis of cultured corneal epithelia is entirely lacritin dependent, and elucidate the mechanism as a rapid autophagic flux to promptly restore cellular metabolism and mitochondrial fusion—in keeping with lacritin’s short residence time on the eye. Accelerated flux appears to derive from lacritin stimulated acetylation of FOXO3 as a novel ligand for ATG101 and coupling of stress acetylated FOXO1 with ATG7 (that remains uncoupled without lacritin), and is sufficient to selectively divert huntingtin mutant Htt103Q aggregates largely without affecting non-aggregated Htt25Q. This is in keeping with stress as a prerequisite for lacritin stimulated autophagy. Lacritin targets the cell surface proteoglycan syndecan-1 via its C-terminal amino acids leu108-leu109phe112, and is also available in saliva, plasma and lung lavage. Thus lacritin may promote epithelial homeostasis widely. BACK TO NEWSLETTER Plasma Metabolomics Identifies Lipid Abnormalities Linked to Markers of Inflammation, Microbial Translocation, and Hepatic Function in HIV Patients Receiving Protease Inhibitors Cassol et al. | BMC Infectious Diseases, 2013 Metabolon results led to: • Biomarkers of advanced HIV subjects, with suspected liver decline • Strategies for attenuating dysregulated immune activation and hepatic dysfunction for HIV patients • Yet another independent study bolstering the case that bile acids should be used as a general marker of hepatic dysfunction Key metabolomic observations: • Many altered lipids–bile acids, sulfated steroids, polyunsaturated fatty acids, and eicosanoids Synopsis Despite the success of combination antiretroviral therapy (ART) for improving morbidity and mortality in HIV subjects, long-term ART is often accompanied by metabolic abnormalities such as insulin resistance, dyslipidemia and lipodystrophy. In order to control these side-effects, a detailed understanding of the underlying mechanisms is required. To this end, investigators performed metabolomics of plasma from two independent cohorts of HIV-infected individuals with late stage disease on PI-based ART. A subset of 35 metabolites strongly segregated disease from healthy with the majority being lipids–bile acids, steroids, and long chain fatty acids (LCFA). Importantly, these metabolites represented 3 clusters correlating with underlying components of the disease or comorbidities–inflammation, microbial translocation, and hepatic function. In fact, bile acids correlated with markers of liver function and fibrosis, providing, escalating support for the use of bile acids for disrupted liver function. BACK TO NEWSLETTER Glycogen Synthesis is a Required Component of the Nitrogen Stress Response in Synechococcus Elongatus PCC 7942 Hickman, J. et al. | Algal Research, 2013 Abstract Carbon fixation and production of reductant by cyanobacteria can exceed new biomass synthesis rates when the supply of essential nutrients is limiting. Under these circumstances metabolic balance is achieved by diversion of excess carbon and reductant to synthesis of glycogen, which can accumulate to more than 50% of cellular dry biomass. We discovered that when glycogen synthesis was abolished, by deletion of the gene for glucose-1-phosphate adenylyl transferase (glgC), Synechococcus elongatus PCC 7942 was unable to degrade its phycobilisomes in response to nitrogen stress. Furthermore, nitrogen deprived glgC null cells recalibrated the levels of glycolytic and TCA cycle intermediates. Specifically, succinate, fumarate, and 2-oxoglutarate, a metabolic indicator of cellular nitrogen status and metabolic effector of the global nitrogen regulator NtcA, accumulated within and were excreted by glgC null cells under nitrogen stress. Moreover, intracellular accumulation and excretion of 2-oxoglutarate from nitrogen stressed glgC null cells coincided temporally with suppression of nblA transcription, while internalization of 2-oxoglutarate by nitrogen deprived wild type cells delayed both nblA expression and phycobilisome degradation. Furthermore, glgC null cells exhibited a nonbleaching phenotype in response to sulfur and phosphate stress. These data indicate that glycogen synthesis is a required component of the global response to nutrient stress. BACK TO NEWSLETTER Mobilization of Lipids and Fortification of Cell Wall and Cuticle are Important in Host Defense Against Hessian Fly Khajuria, C. et al. | BMC Genomics, 2013 Abstract Objectives: Wheat–Hessian fly interaction follows a typical gene-for-gene model. Hessian fly larvae die in wheat plants carrying an effective resistance gene, or thrive in susceptible plants that carry no effective resistance gene. Results: Gene sets affected by Hessian fly attack in resistant plants were found to be very different from those in susceptible plants. Differential expression of gene sets was associated with differential accumulation of intermediates in defense pathways. Our results indicated that resources were rapidly mobilized in resistant plants for defense, including extensive membrane remodeling and release of lipids, sugar catabolism, and amino acid transport and degradation. These resources were likely rapidly converted into defense molecules such as oxylipins; toxic proteins including cysteine proteases, inhibitors of digestive enzymes, and lectins; phenolics; and cell wall components. However, toxicity alone does not cause immediate lethality to Hessian fly larvae. Toxic defenses might slow down Hessian fly development and therefore give plants more time for other types of defense to become effective. Conclusion: Our gene expression and metabolic profiling results suggested that remodeling and fortification of cell wall and cuticle by increased deposition of phenolics and enhanced cross-linking were likely to be crucial for insect mortality by depriving Hessian fly larvae of nutrients from host cells. The identification of a large number of genes that were differentially expressed at different time points during compatible and incompatible interactions also provided a foundation for further research on the molecular pathways that lead to wheat resistance and susceptibility to Hessian fly infestation. BACK TO NEWSLETTER Metabolomic Markers Reveal Novel Pathways of Ageing and Early Development in Human Populations Menni, C. et al. | International Journal of Epidemiology, 2013 Metabolon results led to: • A 22 metabolite panel strongly correlated with age and age-related clinical traits • A single novel metabolite highly correlated with age and ageing traits (e.g. lung function, bone mineral density) Key metabolomic observations: • Validating the approach, the identification of compounds previously reported to associate with aging such as steroids and creatinine • Novel discovery of C-glycosyltryptophan (C-glyTrp) Synopsis Ageing is a multifactorial process with genetic, early developmental, lifestyle, and environmental factors. Discovery of molecular signatures of the aging process can serve to better understand how to control it with diet, lifestyle or pharmaceutical interventions. Thus, investigators used metabolomics to profile 6055 subjects (32–81 years). Statistical analysis produced a panel of 22 metabolites which could be used as a surrogate for age (R2=59%). One of these was the novel metabolite, C-glycosyltryptophan (C-glyTrp). C-glyTrp is strongly associated with a developmental determinant of healthy ageing, birth weight. Further suggesting C-glyTrp may be involved in involved in both ageing and early development were the results of overlaying epigenome-wide association study (EWAS) data that showed that C-glyTrp associated with CpG sites associated with a gene (WDR85) involved in translation, the cell cycle and embryonic development. These results illustrate how metabolomics combined with epigenetics can reveal key molecular mechanisms influencing human health and ageing. BACK TO NEWSLETTER