scholarly journals Comprehensive Analysis of 13C6 Glucose Fate in the Hypoxia-Tolerant Blind Mole Rat Skin Fibroblasts

Metabolites ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 734
Author(s):  
Dmitry Miskevich ◽  
Anastasia Chaban ◽  
Maria Dronina ◽  
Ifat Abramovich ◽  
Eyal Gottlieb ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Hypoxia Inducible Factor ◽  
Lactate Production ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Adaptation To Hypoxia ◽  
Rat Skin ◽  
Terrestrial Mammals ◽  
Mole Rat ◽  
Cytosolic Domain

The bioenergetics of the vast majority of terrestrial mammals evolved to consuming glucose (Glc) for energy production under regular atmosphere (about 21% oxygen). However, some vertebrate species, such as aquatic turtles, seals, naked mole rat, and blind mole rat, Spalax, have adjusted their homeostasis to continuous function under severe hypoxic environment. The exploration of hypoxia-tolerant species metabolic strategies provides a better understanding of the adaptation to hypoxia. In this study, we compared Glc homeostasis in primary Spalax and rat skin cells under normoxic and hypoxic conditions. We used the targeted-metabolomics approach, utilizing liquid chromatography and mass spectrometry (LC-MS) to track the fate of heavy Glc carbons (13C6 Glc), as well as other methodologies to assist the interpretation of the metabolic landscape, such as bioenergetics profiling, Western blotting, and gene expression analysis. The metabolic profile was recorded under steady-state (after 24 h) of the experiment. Glc-originated carbons were unequally distributed between the cytosolic and mitochondrial domains in Spalax cells compared to the rat. The cytosolic domain is dominant apparently due to the hypoxia-inducible factor-1 alpha (HIF-1α) mastering, since its level is higher under normoxia and hypoxia in Spalax cells. Consumed Glc in Spalax cells is utilized for the pentose phosphate pathway maintaining the NADPH pool, and is finally harbored as glutathione (GSH) and UDP-GlcNAc. The cytosolic domain in Spalax cells works in the semi-uncoupled mode that limits the consumed Glc-derived carbons flux to the tricarboxylic acid (TCA) cycle and reduces pyruvate delivery; however, it maintains the NAD+ pool via lactate dehydrogenase upregulation. Both normoxic and hypoxic mitochondrial homeostasis of Glc-originated carbons in Spalax are characterized by their massive cataplerotic flux along with the axis αKG→Glu→Pro→hydroxyproline (HPro). The product of collagen degradation, HPro, as well as free Pro are apparently involved in the bioenergetics of Spalax under both normoxia and hypoxia. The upregulation of 2-hydroxyglutarate production detected in Spalax cells may be involved in modulating the levels of HIF-1α. Collectively, these data suggest that Spalax cells utilize similar metabolic frame for both normoxia and hypoxia, where glucose metabolism is switched from oxidative pathways (conversion of pyruvate to Acetyl-CoA and further TCA cycle processes) to (i) pentose phosphate pathway, (ii) lactate production, and (iii) cataplerotic pathways leading to hexosamine, GSH, and HPro production.

Metabolism of glucose-14C, pyruvate-14C, and mannitol-14C by Melampsora lini. II. Conversion to soluble products

1968 ◽  
Vol 46 (4) ◽  
pp. 453-460 ◽  
Author(s):  
D. Mitchell ◽  
Michael Shaw
Keyword(s):  
Pentose Phosphate Pathway ◽  
Tricarboxylic Acid Cycle ◽  
Rust Fungus ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Soluble Carbohydrates ◽  
Melampsora Lini ◽  
Carbohydrate Fraction ◽  
The Tca Cycle

Mycelium of the flax rust fungus (Melampsora lini (Pers.) Lév.), grown on flax cotyledons in tissue culture, had a mean [Formula: see text]of 4.1 and a mean C6/C1 ratio of 0.14, measured after 4 hours in radioactive glucose. The C6/C1 ratio increased with time and also after treatment with 10−5 M 2,4-dinitrophenol. The relative labelling of the (80%) ethanol-soluble carbohydrates, and organic and amino acid fractions after incubation with glucose-1-, -2-, or -6-14C also indicated preferential release of C1 as 14CO2. Trehalose (unknown A) was tentatively identified in the carbohydrate fraction and was mildly radioactive after incubation of the mycelium with labelled glucose for 3 hours. The principal radioactive products of glucose in this fraction were two unknowns, B and C, which were tentatively identified as mannitol and arabitol. The labelling patterns were consistent with their formation from intermediates of the pentose phosphate pathway. The distribution of radioactivity derived from glucose in alanine, glutamate, and aspartate also indicated that hexose or triose units formed in the pentose phosphate pathway were converted to pyruvate, which either gave rise to alanine or was further oxidized in the tricarboxylic acid cycle. Incubation with pyruvate-1-, -2-, or -3-14C for 3 hours gave rise to 14CO2 and labelled alanine, glutamate, and aspartate in a manner consistent with the operation of the TCA cycle. Mannitol-1-6-14C was not metabolized to any appreciable extent in this period, but did give rise to 14CO2 and to several unidentified compounds in the carbohydrate fraction.

The effect of serum from obese and normal weight men on glucose metabolism in leucocytes

1980 ◽  
Vol 95 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Ole Myking ◽  
Berit Kjøsen ◽  
Hans H. Bassøe
Keyword(s):  
Glucose Metabolism ◽  
Pentose Phosphate Pathway ◽  
Lactate Production ◽  
Normal Weight ◽  
Pentose Phosphate ◽  
Obese Group ◽  
Stimulation Of

Abstract. The influence of pooled serum from either obese or normal weight males on glucose metabolism in human leucocytes has been studied. Leucocytes from normal weight males were incubated with 10–90% pooled serum and either [U-14C], or [1-14C]glucose. Compared to serum from the normal weight males, serum from the obese group had a more stimulating effect on the 14CO2 and [14C]lactate production from [U-14C]glucose and on the 14CO2 production from [1-14C]glucose. The two serum pools had the same stimulating effect on the Embden-Meyerhof pathway as indicated by the formation of [14C]lactate from [1-14C]glucose. Calculations revealed that the activity in the pentose phosphate pathway was stimulated more by serum from obese, than from normal weight males. It is a possibility that increased stimulation of the pentose phosphate pathway may contribute to the development of overweight.

scholarly journals Enhanced glucose metabolism through activation of HIF-1α covers the energy demand in a rat embryonic heart primordium after heartbeat initiation

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Tatsuya Sato ◽  
Nobutoshi Ichise ◽  
Takeshi Kobayashi ◽  
Hiroyori Fusagawa ◽  
Hiroya Yamazaki ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Energy Demand ◽  
Glucose Transporter ◽  
Hypoxia Inducible Factor ◽  
Atp Synthesis ◽  
Pentose Phosphate ◽  
Metabolome Analysis ◽  
Nucleotide Biosynthesis ◽  
Metabolic Characteristics ◽  
Before And After

AbstractThe initiation of heartbeat is an essential step in cardiogenesis in the heart primordium, but it remains unclear how intracellular metabolism responds to increased energy demands after heartbeat initiation. In this study, embryos in Wistar rats at embryonic day 10, at which heartbeat begins in rats, were divided into two groups by the heart primordium before and after heartbeat initiation and their metabolic characteristics were assessed. Metabolome analysis revealed that increased levels of ATP, a main product of glucose catabolism, and reduced glutathione, a by-product of the pentose phosphate pathway, were the major determinants in the heart primordium after heartbeat initiation. Glycolytic capacity and ATP synthesis-linked mitochondrial respiration were significantly increased, but subunits in complexes of mitochondrial oxidative phosphorylation were not upregulated in the heart primordium after heartbeat initiation. Hypoxia-inducible factor (HIF)-1α was activated and a glucose transporter and rate-limiting enzymes of the glycolytic and pentose phosphate pathways, which are HIF-1α-downstream targets, were upregulated in the heart primordium after heartbeat initiation. These results suggest that the HIF-1α-mediated enhancement of glycolysis with activation of the pentose phosphate pathway, potentially leading to antioxidant defense and nucleotide biosynthesis, covers the increased energy demand in the beating and developing heart primordium.

scholarly journals Changes in carbohydrate metabolism of testicular germ cells during meiosis in the rat

1998 ◽  
pp. 322-327 ◽  
Author(s):  
M Bajpai ◽  
G Gupta ◽  
BS Setty
Keyword(s):  
Germ Cells ◽  
Pentose Phosphate Pathway ◽  
Citrate Synthase ◽  
Gradient Centrifugation ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Oxidative Potential ◽  
Tca Cycle Enzymes ◽  
Percoll Density Gradient Centrifugation ◽  
Glycolytic Potential

A study was undertaken to estimate the activities of the key enzymes of glycolysis, the pentose phosphate pathway and the tricarboxylic acid (TCA) cycle in purified rat spermatocytes and spermatids, which have been shown to die in glucose-containing medium and require lactate/pyruvate for maintaining normal ATP concentrations. The aim was to elucidate the changes in the glycolytic and oxidative potential of germ cells undergoing meiosis. Pachytene spermatocytes and round spermatids from adult rat testis were purified to approximately 90% purity by trypsin digestion followed by a combination of centrifugal elutriation and Percoll density gradient centrifugation. After the purity and viability of these cells had been established, their contents of hexokinase, phosphofructokinase, lactate dehydrogenase (LDH) and LDH-X of glycolysis, glucose 6-phosphate dehydrogenase of the pentose phosphate pathway and citrate synthase, aconitase, malate dehydrogenase and 2-oxoglutarate dehydrogenase of the TCA cycle were estimated. These enzymes were also estimated in epididymal spermatozoa for comparison with the testicular germ cells. The results indicate greater activity of glycolytic and pentose phosphate pathway enzymes in spermatocytes than in spermatids, which exhibited greater activity of TCA cycle enzymes than the former. The difference in activity was statistically significant for most of the enzymes studied. In contrast, spermatozoa exhibited markedly greater activity of glycolytic enzymes and significantly lower activity of pentose phosphate pathway and TCA cycle enzymes than did the testicular germ cells. We conclude that the unusual dependence of spermatids exclusively on lactate may be due to their lower glycolytic potential, whereas spermatocytes with comparatively greater glycolytic activity have an intermediate dependence on lactate and are therefore able to utilise lactate, pyruvate, or both, while retaining a better ability to utilise glucose. Spermatozoa with the greatest glycolytic potential and the lowest TCA cycle activity appear to be 'programmed' to utilise exclusively glucose/fructose for energy.

scholarly journals RIP140 inhibits glycolysis-dependent proliferation of cancer cells by regulating transcriptional crosstalk between hypoxia induced factor and p53

2020 ◽  
Author(s):  
Valentin Jacquier ◽  
Delphine Gitenay ◽  
Samuel Fritsch ◽  
Laetitia K. Linares ◽  
Sandrine Bonnet ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cancer Cells ◽  
Pentose Phosphate Pathway ◽  
Glucose Transporter ◽  
Hypoxia Inducible Factor ◽  
Pentose Phosphate ◽  
Cancer Cell Proliferation ◽  
Glycolytic Intermediates ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Block Cell Proliferation

AbstractCancer cells with uncontrolled proliferation preferentially depend on glycolysis to grow, even in the presence of oxygen. Cancer cell proliferation is sustained by the production of glycolytic intermediates, which are diverted into the pentose phosphate pathway. The transcriptional co-regulator RIP140 represses the activity of transcription factors that drive cell proliferation and metabolism, especially glycolysis. However, it is still unknown whether RIP140 is involved in cancer-associated glycolysis deregulation, and whether this involvement could impact tumor cell proliferation. Here we use cell proliferation and metabolic assays to demonstrate that RIP140-deficiency causes a glycolysis-dependent increase in breast tumor growth. RIP140 inhibits the expression of the glucose transporter GLUT3 and of the Glucose-6-Phosphate Dehydrogenase G6PD, the first enzyme of the pentose phosphate pathway. RIP140 thus impacts both this pathway and glycolysis to block cell proliferation. We further demonstrate that RIP140 and p53 jointly inhibit the transcription of the GLUT3 promoter, induced by the hypoxia inducible factor HIF-2α. Overall, our data establish RIP140 as a critical modulator of the p53/HIF cross-talk that controls cancer glycolysis.

scholarly journals Engineering cofactor metabolism for improved protein and glucoamylase production in Aspergillus niger

2020 ◽  
Author(s):  
Yu-fei Sui ◽  
Tabea Schütze ◽  
Li-Ming Ouyang ◽  
Hong-zhong Lu ◽  
Peng Liu ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Aspergillus Niger ◽  
Pentose Phosphate Pathway ◽  
Total Protein ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Gene Copy ◽  
Cofactor Engineering ◽  
Gene Copies ◽  
Glucoamylase Production

Abstract Background: Nicotinamide adenine dinucleotide phosphate (NADPH) is an important cofactor ensuring intracellular redox balance, anabolism and cell growth in all living systems. Our recent multi-omics analyses of glucoamylase (GlaA) biosynthesis in the filamentous fungal cell factory Aspergillus niger indicated that low availability of NADPH might be a limiting factor for GlaA overproduction.Results: We thus employed the Design-Build-Test-Learn cycle for metabolic engineering to identify and prioritize effective cofactor engineering strategies for GlaA overproduction. Based on available metabolomics and 13C metabolic flux analysis data, we individually overexpressed seven predicted genes encoding NADPH generation enzymes under the control of Tet-on gene switch in two A. niger recipient strains, one carrying a single and one carrying seven glaA gene copies, respectively, to test their individual effects on GlaA and total protein overproduction. Both strains were selected to understand if a strong pull towards glaA biosynthesis (seven gene copies) mandates a higher NADPH supply compared to the native condition (one gene copy). Detailed analysis of all 14 strains cultivated in shake flask cultures uncovered that overexpression of the gsdA gene (glucose 6-phosphate dehydrogenase), gndA gene (6-phosphogluconate dehydrogenase) and maeA gene (NADP-dependent malic enzyme) supported GlaA production on a subtle (10%) but significant level in the background strain carrying seven glaA gene copies. We thus performed maltose-limited chemostat cultures combining metabolome analysis for these three isolates to characterize metabolic-level fluctuations caused by cofactor engineering. In these cultures, overexpression of either the gndA or maeA gene increased the intracellular NADPH pool by 45% and 66%, and the yield of GlaA by 65% and 30%, respectively. In contrast, overexpression of the gsdA gene had a negative effect on both total protein and glucoamylase production.Conclusions: This data suggests for the first time that increased NADPH availability can indeed underpin protein and especially GlaA production in strains where a strong pull towards GlaA biosynthesis exists. This data also indicates that the highest impact on GlaA production can be engineered on a genetic level by increasing the flux through the pentose phosphate pathway (gndA gene)reverse TCA cycle (maeA gene) followed by engineering the flux through the reverse TCA cycle (maeA gene) pentose phosphate pathway (gndA gene). We thus propose that NADPH cofactor engineering is indeed a valid strategy for metabolic engineering of A. niger to improve GlaA production, a strategy which is certainly also applicable to the rational design of other microbial cell factories.

scholarly journals RpiR Homologues May Link Staphylococcus aureus RNAIII Synthesis and Pentose Phosphate Pathway Regulation

2011 ◽  
Vol 193 (22) ◽  
pp. 6187-6196 ◽  
Author(s):  
Yefei Zhu ◽  
Renu Nandakumar ◽  
Marat R. Sadykov ◽  
Nandakumar Madayiputhiya ◽  
Thanh T. Luong ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Quorum Sensing ◽  
Pentose Phosphate Pathway ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Virulence Determinants ◽  
Content Type ◽  
Virulence Determinant ◽  
Wide Range ◽  
Cycle Dependent

Staphylococcus aureusis a medically important pathogen that synthesizes a wide range of virulence determinants. The synthesis of many staphylococcal virulence determinants is regulated in part by stress-induced changes in the activity of the tricarboxylic acid (TCA) cycle. One metabolic change associated with TCA cycle stress is an increased concentration of ribose, leading us to hypothesize that a pentose phosphate pathway (PPP)-responsive regulator mediates some of the TCA cycle-dependent regulatory effects. Using bioinformatics, we identified three potential ribose-responsive regulators that belong to the RpiR family of transcriptional regulators. To determine whether these RpiR homologues affect PPP activity and virulence determinant synthesis, therpiRhomologues were inactivated, and the effects on PPP activity and virulence factor synthesis were assessed. Two of the three homologues (RpiRB and RpiRC) positively influence the transcription of the PPP genesrpiAandzwf, while the third homologue (RpiRA) is slightly antagonistic to the other homologues. In addition, inactivation of RpiRC altered the temporal transcription of RNAIII, the effector molecule of theagrquorum-sensing system. These data confirm the close linkage of central metabolism and virulence determinant synthesis, and they establish a metabolic override for quorum-sensing-dependent regulation of RNAIII transcription.

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