The pharmacodynamic and differential gene expression analysis of PPAR α/δ agonist GFT505 in CDAHFD-induced NASH model.

Peroxisome proliferator-activated receptor α/δ (PPAR α/δ), regulating glucolipid metabolism and immune inflammation, has been identified as an effective therapeutic target in non-alcoholic steatohepatitis (NASH). Dual PPAR α/δ agonist, such as GFT505 (also known as elafibranor), demonstrated potential therapeutic effect for NASH in clinical trials. To profile the regulatory network of PPAR α/δ agonist in NASH, the choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) induced NASH model was used to test the pharmacodynamics and transcriptome regulation of GFT505 in this study. The results showed that GFT505 ameliorated hepatic steatosis, inflammation and fibrosis in CDAHFD mice model. RNA-sequencing yielded 3995 up-regulated and 3576 down-regulated genes with GFT505 treatment. And the most significant differentialy expressed genes involved in glucolipid metabolism (Pparα, Acox1, Cpt1b, Fabp4, Ehhadh, Fabp3), inflammation (Ccl6, Ccl9, Cxcl14) and fibrosis (Timp1, Lamc3, Timp2, Col3a1, Col1a2, Col1a1, Hapln4, Timp3, Pik3r5, Pdgfα, Pdgfß, Tgfß1, Tgfß2) were confirmed by RT-qPCR. The down-regulated genes were enriched in cytokine-cytokine receptor interaction pathway and ECM-receptor interaction pathway, while the up-regulated genes were enriched in PPAR signaling pathway and fatty acid degradation pathway. This study provides clues and basis for further understanding on the mechanism of PPAR α/δ agonist on NASH.

The Relationship between Choline Bioavailability from Diet, Intestinal Microbiota Composition, and Its Modulation of Human Diseases.

Choline is a water-soluble nutrient essential for human life. Gut microbial metabolism of choline results in the production of trimethylamine (TMA), which, upon absorption by the host is converted into trimethylamine-N-oxide (TMAO) in the liver. A high accumulation of both components is related to cardiovascular disease, inflammatory bowel disease, non-alcoholic fatty liver disease, and chronic kidney disease. However, the relationship between the microbiota production of these components and its impact on these diseases still remains unknown. In this review, we will address which microbes contribute to TMA production in the human gut, the extent to which host factors (e.g., the genotype) and diet affect TMA production, and the colonization of these microbes and the reversal of dysbiosis as a therapy for these diseases.

Modulation of sodium-coupled choline transporter CHT function in health and disease.

The sodium-coupled high-affinity choline transporter CHT plays a critical role in acetylcholine (ACh) synthesis by taking up the substrate choline from the synaptic cleft after neurotransmitter release; this conservation mechanism is the rate-limiting step for production of ACh, thereby facilitating communication by subsequent action potentials. Mice carrying a null mutation for CHT die within an hour of birth due to respiratory failure, indicating the essential role of CHT proteins for sustaining cholinergic transmission. Choline uptake activity is regulated dynamically by CHT proteins undergoing rapid trafficking between subcellular compartments and the plasma membrane where they are functionally active. CHT proteins internalize from the cell surface into the endolysosomal pathway by a clathrin-mediated mechanism, but can undergo ubiquitination and proteosomal degradation under conditions such as cellular oxidative stress. Over the years, functionally-relevant CHT polymorphisms have been linked to a range of neurological and psychiatric disorders, including ADHD and depression; the impact of these mutations and the extent to which they alter cholinergic signaling have not been addressed fully. Recent studies have identified compounds that can either promote or diminish cholinergic neurotransmission by modulating CHT function, thus having the potential to serve as pharmacological tools or therapeutic prototypes. Here, we review regulation of CHT activity, trafficking and subcellular disposition of CHT proteins, alteration of transporter function in genetic, neurological and psychiatric diseases, and investigations of compounds that modulate activity of the transporter.

Inflammation and oxidative stress transcription profiles due to in vitro supply of methionine with or without choline in unstimulated blood polymorphonuclear leukocytes from lactating Holstein cows.

Neutrophils are the most important polymorphonuclear leukocytes (PMNL), representing the front-line defense involved in pathogen clearance upon invasion. As such, they play a pivotal role in immune and inflammatory responses. Isolated PMNL from 5 mid-lactating Holstein dairy cows were used to evaluate the in vitro effect of methionine (Met) and choline (Chol) supplementation on mRNA expression of genes related to the Met cycle and innate immunity. The target genes are associated with the Met cycle, cell signaling, inflammation, antimicrobial and killing mechanisms, and pathogen recognition. Treatments were allocated in a 3 × 3 factorial arrangement, including 3 Lys-to-Met ratios (L:M, 3.6:1, 2.9:1, or 2.4:1) and 3 levels of supplemental Chol (0, 400, or 800 µg/mL). Three replicates per treatment group were incubated for 2 h at 37°C and 5% atmospheric CO2. Both betaine-homocysteine S-methyltransferase and choline dehydrogenase were undetectable, indicating that PMNL (at least in vitro) cannot generate Met from Chol through the betaine pathway. The PMNL incubated without Chol experienced a specific state of inflammatory mediation [greater interleukin-1ß (IL1B), myeloperoxidase (MPO), IL10, and IL6] and oxidative stress [greater cysteine sulfinic acid decarboxylase (CSAD), cystathionine gamma-lyase (CTH), glutathione reductase (GSR), and glutathione synthase (GSS)]. However, data from the interaction L:M × Chol indicated that this negative state could be overcome by supplementing additional Met. This was reflected in the upregulation of methionine synthase (MTR) and toll-like receptor 2 (TLR2); that is, pathogen detection ability. At the lowest level of supplemental Chol, Met downregulated GSS, GSR, IL1B, and IL6, suggesting it could reduce cellular inflammation and enhance antioxidant status. At 400 µg/mL Chol, supplemental Met upregulated PMNL recognition capacity [higher TLR4 and L-selectin (SELL)]. Overall, enhancing the supply of methyl donors to isolated unstimulated PMNL from mid-lactating dairy cows leads to a low level of PMNL activation and upregulates a cytoprotective mechanism against oxidative stress. Enhancing the supply of Met coupled with adequate Chol levels enhances the gene expression of PMNL pathogen-recognition mechanism. These data suggest that Chol supply to PMNL exposed to low levels of Met effectively downregulated the entire repertoire of innate inflammatory-responsive genes. Thus, Met availability in PMNL during an inflammatory challenge may be sufficient for mounting an appropriate biologic response.

Increased Cholinergic Response in α-Synuclein Transgenic Mice (h-α-synL62).

Pathological accumulation of misfolded α-synuclein (α-syn) in the brain plays a key role in the pathogenesis of Parkinson's disease, leading to neuronal dysfunction and motor disorders. The underlying mechanisms linking α-syn aggregations with neurotransmitter disturbance in Parkinson's brains are not well characterized. In the present study, we investigated transgenic mice expressing an aggregation-prone form of full-length human α-syn (h-α-synL62) linked to a signal sequence. These mice display dopamine depletion and progressive motor deficits. We detected accumulation of α-syn in cholinergic interneurons where they are colocalized with choline acetyltransferase. Using microdialysis, we measured acetylcholine levels in the striatum at baseline and during stimulation in the open field and with scopolamine. While no difference between wild-type and transgenic mice was detected in 3 month old mice, striatal acetylcholine levels at 9 months of age were significantly higher in transgenic mice. Concomitantly, high-affinity choline uptake was also increased while choline acetyltransferase and acetylcholine esterase activities were unchanged. The results suggest a disinhibition of acetylcholine release in α-syn transgenic mice.

MicroRNA-129-5p is regulated by choline availability and controls EGF receptor synthesis and neurogenesis in the cerebral cortex.

Choline availability modulates neurogenesis and cerebral cortex development through the regulation of neural progenitor cell (NPC) proliferative and differentiation capacity. In this study, we demonstrated that cortical NPC self-renewal is controlled by choline via the expression of a microRNA (miR-129-5p), whose role in the developing brain has not been examined, and which, in turn, inhibits synthesis of the epidermal growth factor receptor (EGFR) protein. Specifically, we found that low choline (LC) availability led to the upregulation of miR-129-5p expression in cortical NPCs in vitro and in vivo, causing the downregulation of EGFR and thereby disrupting NPC self-renewal and cortical neurogenesis. Furthermore, in response to LC availability, methylation potential (the S-adenosylmethionine: S-adenosylhomocysteine ratio) in the developing brain was reduced. Restoring methylation potential in LC cortical NPCs led to the re-establishment of normal miR-129-5p expression. We concluded that inhibiting miR-129-5p function and restoring EGFR protein levels in vivo is sufficient to reverse LC-induced defects in cortical NPC self-renewal. For the first time, to our knowledge, we have identified the molecular links that explain how a change in the availability of the diet metabolite choline impacts the essential cellular processes underlying brain development.-Trujillo-Gonzalez, I., Wang, Y., Friday, W. B., Vickers, K. C., Toth, C. L., Molina-Torres, L., Surzenko, N., Zeisel, S. H. MicroRNA-129-5p is regulated by choline availability and controls EGF receptor synthesis and neurogenesis in the cerebral cortex.

Gene cloning, expression and immune adjuvant properties of the recombinant fusion peptide Tα1-BLP on avian influenza inactivate virus vaccine.

Thymosin α1 (Tα1) and bursin-like peptide (BLP) are both immunopotentiators. In order to investigate adjuvant of thymosin α1-bursin-like peptide (Tα1-BLP), we cloned the gene of Tα1-BLP and provided evidence that the gene of Tα1-BLP in a recombinant prokaryotic expression plasmid was successfully expressed in E. coli BL21. To evaluate the immune adjuvant properties of Tα1-BLP, chickens were immunized with Tα1-BLP combined with H9N2 avian influenza whole-inactivated virus (WIV). The titers of HI antibody, antigen-specific antibodies, AIV-neutralizing antibodies, levels of Th1-type cytokines (IFN-γ) and Th2-type cytokines (IL-4) and lymphocyte proliferation responses were determined. What's more, the viral loads and pathologic changes of lung tissue were observed by virus challenge experiment and HE staining to evaluate the immune protection of chickens. We found that Tα1-BLP enhanced HI antibody and antigen-specific IgG antibodies titers, increased the level of AIV-neutralizing antibodies, induced the secretion of Th1- and Th2-type cytokines, and promoted the proliferation of T and B lymphocyte, Furthermore, virus challenge experiment and HE staining confirmed that Tα1-BLP contributed to inhibition replication of the virus from chicken lungs and protected the lungs from damage. Altogether, this study suggested that Tα1-BLP is a novel adjuvant suitable for H9N2 avian influenza vaccine.

Biosynthetic pathways of glycinebetaine in Thalassiosira pseudonana; functional characterization of enzyme catalyzing three-step methylation of glycine.

Betaine (trimethylglycine) is an important compatible solute that accumulates in response to abiotic stresses such as drought and salinity. Biosynthetic pathways of betaine have been extensively studied, but it remains to be clarified on algae. A diatom Thalassiosira pseudonana CCMP1335 is an important component of marine ecosystems. Here we show that the genome sequence of Thalassiosira suggests the presence of two biosynthetic pathways for betaine, via three step methylation of glycine and via two step oxidation of choline. The choline oxidation via choline dehydrogenase was suggested and its sequential characteristics were analyzed. A candidate gene TpORF1 for glycine methylation encodes a protein consisted of 574 amino acids with two putative tandem repeat methyltransferase domains. The TpORF1 was expressed in E. coli, and the purified protein was shown to synthesize betaine via three step methylation of glycine and designated as TpGSDMT. The proteins containing C-terminal half or N-terminal half were expressed in E. coli and exhibited the methyl transferase activities with different substrate specificity for glycine, sarcosine and dimethylglycine. Upregulation of TpGSDMT transcription and betaine levels were observed at high salinity, suggesting the importance of TpGSDMT for salt tolerance in T. pseudonana cells.

MYC is a positive regulator of choline metabolism and impedes mitophagy-dependent necroptosis in diffuse large B-cell lymphoma.

The activation of oncogenes can reprogram tumor cell metabolism. Here, in diffuse large B-cell lymphoma (DLBCL), serum metabolomic analysis revealed that oncogenic MYC could induce aberrant choline metabolism by transcriptionally activating the key enzyme phosphate cytidylyltransferase 1 choline-α (PCYT1A). In B-lymphoma cells, as a consequence of PCYT1A upregulation, MYC impeded lymphoma cells undergo a mitophagy-dependent necroptosis. In DLBCL patients, overexpression of PCYT1A was in parallel with an increase in tumor MYC, as well as a decrease in serum choline metabolite phosphatidylcholine levels and an International Prognostic Index, indicating intermediate-high or high risk. Both in vitro and in vivo, lipid-lowering alkaloid berberine (BBR) exhibited an anti-lymphoma activity through inhibiting MYC-driven downstream PCYT1A expression and inducing mitophagy-dependent necroptosis. Collectively, PCYT1A was upregulated by MYC, which resulted in the induction of aberrant choline metabolism and the inhibition of B-lymphoma cell necroptosis. Referred as a biomarker for DLBCL progression, PCYT1A can be targeted by BBR, providing a potential lipid-modifying strategy in treating MYC-High lymphoma.

Is there an association between enhanced choline and ß-catenin pathway in breast cancer? A pilot study by MR Spectroscopy and ELISA.

Total choline (tCho) was documented as a biomarker for breast cancer diagnosis by in vivo MRS. To understand the molecular mechanisms behind elevated tCho in breast cancer, an association of tCho with ß-catenin and cyclin D1 was evaluated. Hundred fractions from 20 malignant, 10 benign and 20 non-involved breast tissues were isolated. Cytosolic and nuclear expressions of ß-catenin and cyclin D1 were estimated using ELISA. Higher tCho was seen in malignant compared to benign tissues. Malignant tissues showed higher cytosolic and nuclear ß-catenin expressions than benign and non-involved tissues. Within malignant tissues, ß-catenin and cyclin D1 expressions were higher in the nucleus than cytosol. Cyclin D1 expression was higher in the cytosolic fractions of benign and non-involved than malignant tissues. Furthermore, in malignant tissues, tCho showed a positive correlation with the cytosolic and nuclear expression of ß-catenin and cyclin D1 and also a correlation between nuclear expressions of both these proteins was seen. Higher cytosolic ß-catenin expression was seen in progesterone receptor negative than positive patients. Results provide an evidence of correlation between non-invasive biomarker, tCho and the Wnt/ß-catenin pathway. The findings explain the molecular mechanism of tCho elevation which may facilitate exploration of additional therapeutic targets for breast cancer.

Crystal Structure of the Acid Sphingomyelinase-like Phosphodiesterase SMPDL3B Provides Insights into Determinants of Substrate Specificity.

The enzyme acid sphingomyelinase-like phosphodiesterase 3B (SMPDL3B) was shown to act as a negative regulator of innate immune signaling, affecting cellular lipid composition and membrane fluidity. Furthermore, several reports identified this enzyme as an off target of the therapeutic antibody rituximab, with implications in kidney disorders. However, structural information for this protein is lacking. Here we present the high resolution crystal structure of murine SMPDL3B, which reveals a substrate binding site strikingly different from its paralogs. The active site is located in a narrow boot-shaped cavity. We identify a unique loop near the active site that appears to impose size constraints on incoming substrates. A structure in complex with phosphocholine indicates that the protein recognizes this head group via an aromatic box, a typical choline-binding motif. Although a potential substrate for SMPDL3B is sphingomyelin, we identify other possible substrates such as CDP-choline, ATP, and ADP. Functional experiments employing structure-guided mutagenesis in macrophages highlight amino acid residues potentially involved in recognition of endogenous substrates. Our study is an important step toward elucidating the specific function of this poorly characterized enzyme.

Comparative Genome Analysis of the Daptomycin-Resistant Streptococcus anginosus Strain J4206 Associated with Breakthrough Bacteremia.

Streptococcus anginosus is a member of the normal oral flora that can become a pathogen causing pyogenic infections in humans. The genome of daptomycin-resistant strain J4206, originally isolated from a patient suffering from breakthrough bacteremia and septic shock at the University of Texas Health Science Center at San Antonio, was determined. The circular genome is 2,001,352 bp long with a GC content of 38.62% and contains multiple mobile genetic elements, including the phage-like chromosomal island SanCI that mediates a mutator phenotype, transposons, and integrative conjugative elements. Daptomycin resistance involves multiple alterations in the cell membrane and cell wall, and unique features were identified in J4206 that may contribute to resistance. A cluster of capsular polysaccharide (CPS) genes for choline metabolism and transport are present that may help neutralize cell surface charges, destabilizing daptomycin binding. Further, unique J4206 genes encoding sortases and LPXTG-target proteins that are involved in cell wall modification were present. The J4206 genome is phylogenetically closely related to the recently reported vancomycin-resistant SA1 strain; however, these genomes differ with SNPs in cardiolipin synthetase, histidine kinase yycG, teichoic acid modification genes, and other genes involved in cell surface modification. Transmission electron microscopy showed that the cell walls of both strains J4206 and SA1 were significantly thicker and more electron dense than daptomycin- and vancomycin-sensitive strain J4211. This comparative genomic study has identified unique genes as well as allelic variants in the J4206 genome that are involved in cell surface modification and thus might contribute to the acquisition of daptomycin resistance.

Genetic impairments in folate enzymes increase dependence on dietary choline for phosphatidylcholine production at the expense of betaine synthesis.

Although single nucleotide polymorphisms (SNPs) in folate-mediated pathways predict susceptibility to choline deficiency during severe choline deprivation, it is unknown if effects persist at recommended intakes. Thus, we used stable isotope liquid chromatography-mass spectrometry (LC-MS) methodology to examine the impact of candidate SNPs on choline metabolism in a long-term, randomized, controlled feeding trial among pregnant, lactating, and nonpregnant (NP) women consuming 480 or 930 mg/d choline (22% as choline-d9, with d9 indicating a deuterated trimethyl amine group) and meeting folate-intake recommendations. Variants impairing folate metabolism, methylenetetrahydrofolate reductase (MTHFR) rs1801133, methionine synthase (MTR) rs1805087 [wild-type (WT)], MTR reductase (MTRR) rs1801394, and methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase (MTHFD1) rs2236225, influenced choline dynamics, frequently through interactions with reproductive state and choline intake, with fewer genotypic alterations observed among pregnant women. Women with these variants partitioned more dietary choline toward phosphatidylcholine (PC) biosynthesis via the cytidine diphosphate (CDP)-choline pathway at the expense of betaine synthesis even when use of betaine as a methyl donor was increased. Choline intakes of 930 mg/d restored partitioning of dietary choline between betaine and CDP-PC among NP (MTHFR rs1801133 and MTR rs1805087 WT) and lactating (MTHFD1 rs2236225) women with risk genotypes. Overall, our findings indicate that loss-of-function variants in folate-metabolizing enzymes strain cellular PC production, possibly via impaired folate-dependent phosphatidylethanolamine-N-methyltransferase (PEMT)-PC synthesis, and suggest that women with these risk genotypes may benefit from choline intakes exceeding current recommendations.-Ganz, A. B., Shields, K., Fomin, V. G., Lopez, Y. S., Mohan, S., Lovesky, J., Chuang, J. C., Ganti, A., Carrier, B., Yan, J., Taeswuan, S., Cohen, V. V., Swersky, C. C., Stover, J. A., Vitiello, G. A., Malysheva, O. V., Mudrak, E., Caudill, M. A. Genetic impairments in folate enzymes increase dependence on dietary choline for phosphatidylcholine production at the expense of betaine synthesis.

Fine-tuning of choline metabolism is important for pneumococcal colonization.

The human pathogen Streptococcus pneumoniae (the pneumococcus) is rare in having a strict requirement for the amino alcohol choline, which decorates pneumococcal teichoic acids. This process relies on the lic locus, containing the lic1 and lic2 operons. These operons produce eight proteins that import and metabolize choline, generate teichoic acid precursors and decorate these with choline. Three promoters control expression of lic operons, with Plic1P1 and Plic1P2 controlling lic1 and Plic2 controlling lic2. To investigate the importance of lic regulation for pneumococci, we assayed the activity of transcriptional fusions of the three lic promoters to the luciferase reporter gene. Plic1P1 , whose activity depends on the response regulator CiaR, responded to fluctuations in extracellular choline, with activity increasing greatly upon choline depletion. We uncovered a complex regulatory mechanism controlling Plic1P1 , involving activity driven by CiaR, repression by putative repressor LicR in the presence of choline, and derepression upon choline depletion mediated by LicC, a choline metabolism enzyme. Finally, the ability to regulate Plic1P1 in response to choline was important for pneumococcal colonization. We suggest that derepression of Plic1P1 upon choline depletion maximizing choline internalization constitutes an adaptive response mechanism allowing pneumococci to optimize growth and survival in environments where choline is scarce.

Evidence for negative selection of gene variants that increase dependence on dietary choline in a Gambian cohort.

Choline is an essential nutrient, and the amount needed in the diet is modulated by several factors. Given geographical differences in dietary choline intake and disparate frequencies of single-nucleotide polymorphisms (SNPs) in choline metabolism genes between ethnic groups, we tested the hypothesis that 3 SNPs that increase dependence on dietary choline would be under negative selection pressure in settings where choline intake is low: choline dehydrogenase (CHDH) rs12676, methylenetetrahydrofolate reductase 1 (MTHFD1) rs2236225, and phosphatidylethanolamine-N-methyltransferase (PEMT) rs12325817. Evidence of negative selection was assessed in 2 populations: one in The Gambia, West Africa, where there is historic evidence of a choline-poor diet, and the other in the United States, with a comparatively choline-rich diet. We used 2 independent methods, and confirmation of our hypothesis was sought via a comparison with SNP data from the Maasai, an East African population with a genetic background similar to that of Gambians but with a traditional diet that is higher in choline. Our results show that frequencies of SNPs known to increase dependence on dietary choline are significantly reduced in the low-choline setting of The Gambia. Our findings suggest that adequate intake levels of choline may have to be reevaluated in different ethnic groups and highlight a possible approach for identifying novel functional SNPs under the influence of dietary selective pressure.

Choline kinase-alpha by regulating cell aggressiveness and drug sensitivity is a potential druggable target for ovarian cancer.

BACKGROUND: Aberrant choline metabolism has been proposed as a novel cancer hallmark. We recently showed that epithelial ovarian cancer (EOC) possesses an altered MRS-choline profile, characterised by increased phosphocholine (PCho) content to which mainly contribute over-expression and activation of choline kinase-alpha (ChoK-alpha). METHODS: To assess its biological relevance, ChoK-alpha expression was downmodulated by transient RNA interference in EOC in vitro models. Gene expression profiling by microarray analysis and functional analysis was performed to identify the pathway/functions perturbed in ChoK-alpha-silenced cells, then validated by in vitro experiments. RESULTS: In silenced cells, compared with control, we observed: (I) a significant reduction of both CHKA transcript and ChoK-alpha protein expression; (II) a dramatic, proportional drop in PCho content ranging from 60 to 71%, as revealed by (1)H-magnetic spectroscopy analysis; (III) a 35-36% of cell growth inhibition, with no evidences of apoptosis or modification of the main cellular survival signalling pathways; (IV) 476 differentially expressed genes, including genes related to lipid metabolism. Ingenuity pathway analysis identified cellular functions related to cell death and cellular proliferation and movement as the most perturbed. Accordingly, CHKA-silenced cells displayed a significant delay in wound repair, a reduced migration and invasion capability were also observed. Furthermore, although CHKA silencing did not directly induce cell death, a significant increase of sensitivity to platinum, paclitaxel and doxorubicin was observed even in a drug-resistant context. CONCLUSION: We showed for the first time in EOC that CHKA downregulation significantly decreased the aggressive EOC cell behaviour also affecting cells' sensitivity to drug treatment. These observations open the way to further analysis for ChoK-alpha validation as a new EOC therapeutic target to be used alone or in combination with conventional drugs.

Prognostic relationship of metabolic profile obtained of melanoma B16F10.

Melanoma is a type of cancer that reaches more people in the world, characterized by genetic mutations that trigger the growth of disorganized cells. The diagnosis of skin tumors by invasive techniques has become a risk to the patients, so the search for new non-invasive techniques has been the subject of research in recent years. The objective of this work is to propose a non-invasive method prognosis based on the identification of specific biomarkers of the cancer, known as metabolomics analysis. For this study, we used B16F10 melanoma tumor cells and metabolic profiles were obtained at three time-periods by (1)HNMR and comparison with the cell cycle, apoptosis pathways and proliferation index. The metabolic profiles show the relationship between the metabolites found with energy metabolism, pathways of apoptosis and proliferation, which showed increases in proportion during growth and progression. Were found 29 metabolites, of which the differentially expressed are: lactate, aspartate, glycerol, lipids, alanine, myo-inositol, phosphocholine, choline, acetate, creatine and taurine. Choline and creatine are closely related with tumor progression, and are inversely expressed in later stages of tumor growth, which demonstrates the ability to be markers of tumor progression or monitoring the pharmacological efficacy when combined with other therapies. We conclude that the metabolome appeared as effective non-invasive technique predicts, besides providing possible biomarkers of melanoma.

The role of phosphatidylcholine and choline metabolites to cell proliferation and survival.

The reorganization of metabolic pathways in cancer facilitates the flux of carbon and reducing equivalents into anabolic pathways at the expense of oxidative phosphorylation. This provides rapidly dividing cells with the necessary precursors for membrane, protein and nucleic acid synthesis. A fundamental metabolic perturbation in cancer is the enhanced synthesis of fatty acids by channeling glucose and/or glutamine into cytosolic acetyl-CoA and upregulation of key biosynthetic genes. This lipogenic phenotype also extends to the production of complex lipids involved in membrane synthesis and lipid-based signaling. Cancer cells display sensitivity to ablation of fatty acid synthesis possibly as a result of diminished capacity to synthesize complex lipids involved in signaling or growth pathways. Evidence has accrued that phosphatidylcholine, the major phospholipid component of eukaryotic membranes, as well as choline metabolites derived from its synthesis and catabolism, contribute to both proliferative growth and programmed cell death. This review will detail our current understanding of how coordinated changes in substrate availability, gene expression and enzyme activity lead to altered phosphatidylcholine synthesis in cancer, and how these changes contribute directly or indirectly to malignant growth. Conversely, apoptosis targets key steps in phosphatidylcholine synthesis and degradation that are linked to disruption of cell cycle regulation, reinforcing the central role that phosphatidylcholine and its metabolites in determining cell fate.

Genetic signatures in choline and 1-carbon metabolism are associated with the severity of hepatic steatosis.

Choline metabolism is important for very low-density lipoprotein secretion, making this nutritional pathway an important contributor to hepatic lipid balance. The purpose of this study was to assess whether the cumulative effects of multiple single nucleotide polymorphisms (SNPs) across genes of choline/1-carbon metabolism and functionally related pathways increase susceptibility to developing hepatic steatosis. In biopsy-characterized cases of nonalcoholic fatty liver disease and controls, we assessed 260 SNPs across 21 genes in choline/1-carbon metabolism. When SNPs were examined individually, using logistic regression, we only identified a single SNP (PNPLA3 rs738409) that was significantly associated with severity of hepatic steatosis after adjusting for confounders and multiple comparisons (P=0.02). However, when groupings of SNPs in similar metabolic pathways were defined using unsupervised hierarchical clustering, we identified groups of subjects with shared SNP signatures that were significantly correlated with steatosis burden (P=0.0002). The lowest and highest steatosis clusters could also be differentiated by ethnicity. However, unique SNP patterns defined steatosis burden irrespective of ethnicity. Our results suggest that analysis of SNP patterns in genes of choline/1-carbon metabolism may be useful for prediction of severity of steatosis in specific subsets of people, and the metabolic inefficiencies caused by these SNPs should be examined further.

The heritability of brain metabolites on proton magnetic resonance spectroscopy in older individuals.

Twin studies have shown that many aspects of brain structure are heritable, suggesting a strong genetic contribution to brain structure. Less is known about functional aspects of the brain, in particular biologically relevant metabolites in the brain such as those measured by proton magnetic resonance spectroscopy (((1))H MRS), N-acetyl-aspartate (NAA), creatine (Cr), choline (Cho) and myoinositol (ml), which have been suggested as possible markers of brain aging and early dementia. We examined 296 (56 male/108 female monozygotic and 43 male/89 female dizygotic) older twins (mean age 72.2 ± 5.5 years, range 65-88), for the levels of these metabolites relative to the H(2)O signal in the posterior cingulate cortex using ((1))H MRS. All metabolites showed substantial heritability, which was greatest for the neuronal integrity marker NAA (72%), and less so for the others - Cr (51%), Cho (33%) and ml (55%). The heritability of these markers did not change significantly with age or sex. The genetic determination of NAA, along with the evidence that NAA levels change in aging and neurodegenerative diseases suggest that it is a potential endophenotype of brain aging and dementia.