DDRE-22. DISRUPTING REDOX BALANCE VIA THE TETRAHYDROBIOPTERIN PATHWAY IN GLIOBLASTOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi79-vi79
Author(s):  
Kaysaw Tuy ◽  
Sajina GC ◽  
Wei Chen ◽  
David Harrison ◽  
John Aleman ◽  
...  
Keyword(s):  
Preliminary Data ◽  
De Novo ◽  
In Silico Analysis ◽  
Redox Balance ◽  
De Novo Synthesis ◽  
Tumor Initiating Cells ◽  
Recurrent Gliomas ◽  
Mitochondrial Ros ◽  
Therapeutic Opportunity ◽  
Approved Drugs

Abstract Aberrant redox statuses are observed in glioblastoma (GBM), and we previously identified GTP cyclohydrolase I (GCH1) to be a redox regulator upregulated in brain tumor initiating cells (BTICs). GCH1 is a rate-limiting enzyme in the de novo synthesis of tetrahydrobiopterin (BH4), a cofactor that produces catecholamine precursors and nitric oxide (NO) and, once used, becomes 7,8-dihydrobiopterin (BH2). Regeneration of BH2 into BH4 by dihydrofolate reductase (DHFR) helps to maintain proper BH4/BH2 ratios for redox balance. Although the BH4 pathway has traditionally been studied in the vasculature system for its regulation of NO, our previous work and that of others suggests the GCH1/BH4 pathway plays a critical redox role including in neoplastic cells. In silico analysis of primary and recurrent gliomas indicate high expression of BH4 related enzymes that correlated with worse patient survival in both primary and recurrent gliomas. The observed elevation of the BH4 pathway not only emphasizes its importance, but a therapeutic opportunity for improving survival in glioma patients. By repurposing FDA approved drugs known to cross the blood brain barrier and previously suggested as anti-glioma therapies, combining inhibitors for the de novo synthesis (sulfasalazine) and regeneration (pyrimethamine) of BH4 could prove to be an effective strategy for targeting the GCH1/BH4 through redox disruption. Preliminary data BTICs isolated from patient derived xenografts (PDXs) indicated reduced viability when treated with sulfasalazine (SASP) and pyrimethamine (PYR). Furthermore, we observed lower/depleted levels of BH4 relative to BH2 when BTICs were treated with SASP and PYR. Lastly, there is an increase in mitochondrial ROS upon SASP and PYR treatment, suggesting dysregulated redox states. Importantly, temozolomide resistant GBM cells remained sensitive to SASP and PYR. Taken together, our preliminary data suggests the plausibility of targeting the GCH1/BH4 pathway with SASP and PYR to disrupt redox balance in glioma through the depletion of BH4.

scholarly journals Pathway analysis of NAD+ metabolism

2011 ◽  
Vol 439 (2) ◽  
pp. 341-348 ◽  
Author(s):  
Luis F. de Figueiredo ◽  
Toni I. Gossmann ◽  
Mathias Ziegler ◽  
Stefan Schuster
Keyword(s):  
Dna Repair ◽  
De Novo ◽  
Redox Balance ◽  
Transfer Reactions ◽  
Biosynthetic Pathways ◽  
De Novo Synthesis ◽  
Systematic Analysis ◽  
Nad Metabolism ◽  
Nad Synthesis ◽  
Futile Cycles

NAD+ is well known as a crucial cofactor in the redox balance of metabolism. Moreover, NAD+ is degraded in ADP-ribosyl transfer reactions, which are important components of multitudinous signalling reactions. These include reactions linked to DNA repair and aging. In the present study, using the concept of EFMs (elementary flux modes), we established all of the potential routes in a network describing NAD+ biosynthesis and degradation. All known biosynthetic pathways, which include de novo synthesis starting from tryptophan as well as the classical Preiss–Handler pathway and NAD+ synthesis from other vitamin precursors, were detected as EFMs. Moreover, several EFMs were found that degrade NAD+, represent futile cycles or have other functionalities. The systematic analysis and comparison of the networks specific for yeast and humans document significant differences between species with regard to the use of precursors, biosynthetic routes and NAD+-dependent signalling.

scholarly journals Glutathione de novo synthesis but not recycling process coordinates with glutamine catabolism to control redox homeostasis and directs murine T cell differentiation

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Gaojian Lian ◽  
JN Rashida Gnanaprakasam ◽  
Tingting Wang ◽  
Ruohan Wu ◽  
Xuyong Chen ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
T Cell ◽  
Cell Fate ◽  
De Novo ◽  
Redox Homeostasis ◽  
Redox Balance ◽  
T Cell Differentiation ◽  
De Novo Synthesis ◽  
Autoimmune Encephalomyelitis ◽  
Glutamate Cysteine Ligase

Upon antigen stimulation, T lymphocytes undergo dramatic changes in metabolism to fulfill the bioenergetic, biosynthetic and redox demands of proliferation and differentiation. Glutathione (GSH) plays an essential role in controlling redox balance and cell fate. While GSH can be recycled from Glutathione disulfide (GSSG), the inhibition of this recycling pathway does not impact GSH content and murine T cell fate. By contrast, the inhibition of the de novo synthesis of GSH, by deleting either the catalytic (Gclc) or the modifier (Gclm) subunit of glutamate–cysteine ligase (Gcl), dampens intracellular GSH, increases ROS, and impact T cell differentiation. Moreover, the inhibition of GSH de novo synthesis dampened the pathological progression of experimental autoimmune encephalomyelitis (EAE). We further reveal that glutamine provides essential precursors for GSH biosynthesis. Our findings suggest that glutamine catabolism fuels de novo synthesis of GSH and directs the lineage choice in T cells.

scholarly journals In silico analysis of phag-like protein in Ralstonia Euthropa H16, potentially involved in polyhydroxyalkanoates synthesis

2019 ◽  
Vol 15 (29) ◽  
pp. 55-64
Author(s):  
Melissa Uribe Acosta ◽  
Andrés Felipe Villa Restrepo
Keyword(s):  
Gene Deletion ◽  
De Novo ◽  
Ralstonia Eutropha ◽  
Carbon Sources ◽  
Model Organism ◽  
In Silico Analysis ◽  
De Novo Synthesis ◽  
Storage Material ◽  
Fas Pathway ◽  
Silico Analysis

Polyhydroxyalkanoates (PHA) are synthesised by bacteria as carbon storage material. The protein PhaG directs carbon from non-related carbon sources such as glycerol, metabolised through fatty acid de novo synthesis (FAS) pathway, with PHA synthesis. The gene that codifies for this protein has not yet been found in the genome of Ralstonia eutropha H16, a model organism. By bioinformatic comparison to already known PhaG proteins, a PhaG-like protein was found codified by gene H16_A0147 and presence of the gene was preliminary confirmed by PCR. This is the first study that shows the presence and characteristics of a PhaG-like protein in R. eutropha H16 and represents the first step for the identification of a connection between FAS and PHA pathways in this model bacterium. Further gene deletion and enzymatic activity studies are necessary to confirm this potential relationship, which could improve industrial PHA production and utilisation of agro-industrial residues such as glycerol.

Characterization of Monocyte-Associated Factor V

1993 ◽  
Vol 70 (02) ◽  
pp. 273-280 ◽  
Author(s):  
Janos Kappelmayer ◽  
Satya P Kunapuli ◽  
Edward G Wyshock ◽  
Robert W Colman
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Peripheral Blood ◽  
De Novo ◽  
Factor V ◽  
Blood Monocytes ◽  
De Novo Synthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Umbilical Vein ◽  
Time Dependent ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Tumor Promotor ◽  
Coagulation Assay ◽  
Platelet Aggregates ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

DE NOVO SYNTHESIS OF STEROIDS BY THE TESTES OF THE HUMAN FOETUS AT MIDGESTATION

1971 ◽  
Vol 68 (1_Supplb) ◽  
pp. S135 ◽  
Author(s):  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
De Novo ◽  
De Novo Synthesis ◽  
Human Foetus

In vivo study of the biosynthesis of long-chain fatty acids using deuterated water

1995 ◽  
Vol 269 (2) ◽  
pp. E247-E252 ◽  
Author(s):  
H. O. Ajie ◽  
M. J. Connor ◽  
W. N. Lee ◽  
S. Bassilian ◽  
E. A. Bergner ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
De Novo ◽  
Chain Elongation ◽  
Deuterated Water ◽  
De Novo Synthesis ◽  
Isotopomer Distribution ◽  
Long Chain ◽  
Mass Isotopomer

To determine the contributions of preexisting fatty acid, de novo synthesis, and chain elongation in long-chain fatty acid (LCFA) synthesis, the synthesis of LCFAs, palmitate (16:0), stearate (18:0), arachidate (20:0), behenate (22:0), and lignocerate (24:0), in the epidermis, liver, and spinal cord was determined using deuterated water and mass isotopomer distribution analysis in hairless mice and Sprague-Dawley rats. Animals were given 4% deuterated water for 5 days or 8 wk in their drinking water. Blood was withdrawn at the end of these times for the determination of deuterium enrichment, and the animals were killed to isolate the various tissues for lipid extraction for the determination of the mass isotopomer distributions. The mass isotopomer distributions in LCFA were incompatible with synthesis from a single pool of primer. The synthesis of palmitate, stearate, arachidate, behenate, and lignocerate followed the expected biochemical pathways for the synthesis of LCFAs. On average, three deuterium atoms were incorporated for every addition of an acetyl unit. The isotopomer distribution resulting from chain elongation and de novo synthesis can be described by the linear combination of two binomial distributions. The proportions of preexisting, chain elongation, and de novo-synthesized fatty acids as a percentage of the total fatty acids were determined using multiple linear regression analysis. Fractional synthesis was found to vary, depending on the tissue type and the fatty acid, from 47 to 87%. A substantial fraction (24-40%) of the newly synthesized molecules was derived from chain elongation of unlabeled (recycled) palmitate.

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