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Nature Metabolism Sep 2020The mechanistic target of rapamycin complex 1 (mTORC1) kinase regulates cell growth by setting the balance between anabolic and catabolic processes. To be active, mTORC1...
The mechanistic target of rapamycin complex 1 (mTORC1) kinase regulates cell growth by setting the balance between anabolic and catabolic processes. To be active, mTORC1 requires the environmental presence of amino acids and glucose. While a mechanistic understanding of amino acid sensing by mTORC1 is emerging, how glucose activates mTORC1 remains mysterious. Here, we used metabolically engineered human cells lacking the canonical energy sensor AMP-activated protein kinase to identify glucose-derived metabolites required to activate mTORC1 independent of energetic stress. We show that mTORC1 senses a metabolite downstream of the aldolase and upstream of the GAPDH-catalysed steps of glycolysis and pinpoint dihydroxyacetone phosphate (DHAP) as the key molecule. In cells expressing a triose kinase, the synthesis of DHAP from DHA is sufficient to activate mTORC1 even in the absence of glucose. DHAP is a precursor for lipid synthesis, a process under the control of mTORC1, which provides a potential rationale for the sensing of DHAP by mTORC1.
Topics: AMP-Activated Protein Kinases; Dihydroxyacetone; Dihydroxyacetone Phosphate; Energy Metabolism; Fructose-Bisphosphate Aldolase; Glucose; Glycolysis; HEK293 Cells; Humans; Lipid Metabolism; Phosphotransferases (Alcohol Group Acceptor); TOR Serine-Threonine Kinases
PubMed: 32719541
DOI: 10.1038/s42255-020-0250-5 -
Nature Communications Jul 2023Neutrophils rely predominantly on glycolytic metabolism for their biological functions, including reactive oxygen species (ROS) production. Although pyruvate kinase M2...
Neutrophils rely predominantly on glycolytic metabolism for their biological functions, including reactive oxygen species (ROS) production. Although pyruvate kinase M2 (PKM2) is a glycolytic enzyme known to be involved in metabolic reprogramming and gene transcription in many immune cell types, its role in neutrophils remains poorly understood. Here, we report that PKM2 regulates ROS production and microbial killing by neutrophils. Zymosan-activated neutrophils showed increased cytoplasmic expression of PKM2. Pharmacological inhibition or genetic deficiency of PKM2 in neutrophils reduced ROS production and Staphylococcus aureus killing in vitro. In addition, this also resulted in phosphoenolpyruvate (PEP) accumulation and decreased dihydroxyacetone phosphate (DHAP) production, which is required for de novo synthesis of diacylglycerol (DAG) from glycolysis. In vivo, PKM2 deficiency in myeloid cells impaired the control of infection with Staphylococcus aureus. Our results fill the gap in the current knowledge of the importance of lower glycolysis for ROS production in neutrophils, highlighting the role of PKM2 in regulating the DHAP and DAG synthesis to promote ROS production in neutrophils.
Topics: Pyruvate Kinase; Reactive Oxygen Species; Neutrophils; Phosphorylation; Glycolysis
PubMed: 37460614
DOI: 10.1038/s41467-023-40021-6 -
Biotechnology For Biofuels 2016Biodiesel can replace petroleum diesel as it is produced from animal fats and vegetable oils, and it produces about 10 % (w/w) glycerol, which is a promising new... (Review)
Review
Biodiesel can replace petroleum diesel as it is produced from animal fats and vegetable oils, and it produces about 10 % (w/w) glycerol, which is a promising new industrial microbial carbon, as a major by-product. One of the most potential applications of glycerol is its biotransformation to high value chemicals such as 1,3-propanediol (1,3-PD), dihydroxyacetone (DHA), succinic acid, etc., through microbial fermentation. Glycerol dehydratase, 1,3-propanediol dehydrogenase (1,3-propanediol-oxydoreductase), and glycerol dehydrogenase, which were encoded, respectively, by dhaB, dhaT, and dhaD and with DHA kinase are encompassed by the dha regulon, are the three key enzymes in glycerol bioconversion into 1,3-PD and DHA, and these are discussed in this review article. The summary of the main research direction of these three key enzyme and methods of glycerol bioconversion into 1,3-PD and DHA indicates their potential application in future enzymatic research and industrial production, especially in biodiesel industry.
PubMed: 26966462
DOI: 10.1186/s13068-016-0473-6 -
Cell Cycle (Georgetown, Tex.) Jun 2019Mature human erythrocytes are dependent on anerobic glycolysis, i.e. catabolism (oxidation) of one glucose molecule to produce two ATP and two lactate molecules.... (Review)
Review
Mature human erythrocytes are dependent on anerobic glycolysis, i.e. catabolism (oxidation) of one glucose molecule to produce two ATP and two lactate molecules. Proliferating tumor cells mimick mature human erythrocytes to glycolytically generate two ATP molecules. They deliberately avoid or switch off their respiration, i.e. tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) machinery and consequently dispense with the production of additional 36 ATP molecules from one glucose molecule. This phenomenon is named aerobic glycolysis or Warburg effect. The present review deals with the fate of a glucose molecule after entering a mature human erythrocyte or a proliferating tumor cell and describes why it is useful for a proliferating tumor cell to imitate a mature erythrocyte. Blood consisting of plasma and cellular components (99% of the cells are erythrocytes) may be regarded as a mobile organ, constantly exercising a direct interaction with other organs. Therefore, the use of drugs, which influences the biological activity of erythrocytes, has an immediate effect on the entire organism. : TCA: tricarboxylic acid cycle; OXPHOS: oxidative phosphorylation; GSH: reduced state of glutathione; NFκB: Nuclear factor of kappa B; PKB (Akt): protein kinase B; NOS: nitric oxide synthase; IgG: immune globulin G; HS: hydrogen sulfide; slanDCs: Human 6-sulfo LacNAc-expressing dendritic cells; IL-8: interleukin-8; LPS: lipopolysaccharide; ROS: reactive oxygen species; PPP: pentose phosphate pathway; NADPH: nicotinamide adenine dinucleotide phosphate hydrogen; R5P: ribose-5-phophate; NAD: nicotinamide adenine dinucleotide; FAD: flavin adenine dinucleotide; O: superoxide anion; G6P: glucose 6-phosphate; HbO: Oxyhemoglobin; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GAP: glyceraldehyde-3-phosphate; 1,3-BPG: 1,3-bis-phosphoglycerate; 2,3-BPG: 2,3-bisphosphoglycerte; PGAM1: phosphoglycerate mutase 1; 3-PG: 3-phosphoglycerate; 2-PG: 2-phosphoglycerate; MIPP1: Multiple inositol polyphosphate phosphatase; mTORC1: mammalian target of rapamycin complex 1; Ru5P: ribulose 5-phosphate; ox-PPP: oxidative branch of pentose phosphate pathway; PGK: phosphoglycerate kinase; IFN-γ: interferon-γ; LDH: lactate dehydrogenase; STAT3: signal transducer and activator of transcription 3; Rheb: Ras homolog enriched in Brain; HO: hydrogen peroxide; ROOH: lipid peroxide; SOD: superoxide dismutase; MRC: mitochondrial respiratory chain; MbFe-O: methmyoglobin; RNR: ribonucleotide reductase; PRPP: phosphoribosylpyrophosphate; PP: pyrophosphate; GSSG: oxidized state of glutathione; non-ox-PPP: non-oxidative branch of pentose phosphate pathway; RPI: ribose-5-phosphate isomerase; RPE: ribulose 5-phosphate 3-epimerase; X5P: xylulose 5-phosphate; TK: transketolase; TA: transaldolase; F6P: fructose-6-phosphate; AR2: aldose reductase 2; SD: sorbitol dehydrogenase; HK: hexokinase; MG: mehtylglyoxal; DHAP: dihydroxyacetone phosphate; TILs: tumor-infiltrating lymphocytes; MCTs: monocarboxylate transporters; pHi: intracellular pH; Hif-1α: hypoxia-induced factor 1; NHE1: sodium/H (Na/H) antiporter 1; V-ATPase: vacuolar-type proton ATPase; CAIX: carbonic anhydrase; CO: carbon dioxide; HCO: bicarbonate; NBC: sodium/bicarbonate (Na/HCO) symporter; pHe: extracellular pH; GLUT-1: glucose transporter 1; PGK-1: phosphoglycerate kinase 1.
Topics: Carcinogenesis; Cell Proliferation; Erythrocytes; Glucose; Glycolysis; Humans; Neoplasms
PubMed: 31154896
DOI: 10.1080/15384101.2019.1618125 -
Polymers May 2023Bacterial immobilization is regarded as an enabling technology to improve the stability and reusability of biocatalysts. Natural polymers are often used as...
Bacterial immobilization is regarded as an enabling technology to improve the stability and reusability of biocatalysts. Natural polymers are often used as immobilization matrices but present certain drawbacks, such as biocatalyst leakage and loss of physical integrity upon utilization in bioprocesses. Herein, we prepared a hybrid polymeric matrix that included silica nanoparticles for the unprecedented immobilization of the industrially relevant (Gfr). This biocatalyst can valorize glycerol, an abundant by-product of the biodiesel industry, into glyceric acid (GA) and dihydroxyacetone (DHA). Different concentrations of siliceous nanosized materials, such as biomimetic Si nanoparticles (SiNps) and montmorillonite (MT), were added to alginate. These hybrid materials were significantly more resistant by texture analysis and presented a more compact structure as seen by scanning electron microscopy. The preparation including 4% alginate with 4% SiNps proved to be the most resistant material, with a homogeneous distribution of the biocatalyst in the beads as seen by confocal microscopy using a fluorescent mutant of Gfr. It produced the highest amounts of GA and DHA and could be reused for up to eight consecutive 24 h reactions with no loss of physical integrity and negligible bacterial leakage. Overall, our results indicate a new approach to generating biocatalysts using hybrid biopolymer supports.
PubMed: 37299313
DOI: 10.3390/polym15112514 -
Chemical Research in Toxicology Apr 2022Dihydroxyacetone (DHA) is a major byproduct of e-cigarette combustion and is the active ingredient in sunless tanning products. Mounting evidence points to its damaging...
Dihydroxyacetone (DHA) is a major byproduct of e-cigarette combustion and is the active ingredient in sunless tanning products. Mounting evidence points to its damaging effects on cellular functions. While developing a simple synthetic route to monomeric [C]DHA for flux metabolic studies that compared DHA and glyceraldehyde (GA) metabolism, we uncovered that solid DHA ages upon storage and differences in the relative abundance of each of its isomer occur when reconstituted in an aqueous solution. While all three of the dimeric forms of DHA ultimately resolve to the ketone and hydrated forms of monomeric DHA once in water at room temperature, these species require hours rather than minutes to reach an equilibrium favoring the monomeric species. Consequently, when used in bolus or flux experiments, the relative abundance of each isomer and its effects at the time of application is dependent on the initial DHA isomeric composition and concentration, and time of equilibration in solution before use. Here, we make recommendations for the more consistent handling of DHA as we report conditions that ensure that DHA is present in its monomeric form while in solutions, conditions used in an isotopic tracing study that specifically compared monomeric DHA and GA metabolism in cells.
Topics: Dihydroxyacetone; Electronic Nicotine Delivery Systems; Isomerism; Solutions
PubMed: 35324152
DOI: 10.1021/acs.chemrestox.1c00403 -
NMR in Biomedicine Oct 2019Glycolysis is a fundamental metabolic process in all organisms. Anomalies in glucose metabolism are linked to various pathological conditions. In particular, elevated... (Review)
Review
Glycolysis is a fundamental metabolic process in all organisms. Anomalies in glucose metabolism are linked to various pathological conditions. In particular, elevated aerobic glycolysis is a characteristic feature of rapidly growing cells. Glycolysis and the closely related pentose phosphate pathway can be monitored in real time by hyperpolarized C-labeled metabolic substrates such as C-enriched, deuterated D-glucose derivatives, [2- C]-D-fructose, [2- C] dihydroxyacetone, [1- C]-D-glycerate, [1- C]-D-glucono-δ-lactone and [1- C] pyruvate in healthy and diseased tissues. Elevated glycolysis in tumors (the Warburg effect) was also successfully imaged using hyperpolarized [U- C , U- H ]-D-glucose, while the size of the preexisting lactate pool can be measured by C MRS and/or MRI with hyperpolarized [1- C]pyruvate. This review summarizes the application of various hyperpolarized C-labeled metabolites to the real-time monitoring of glycolysis and related metabolic processes in normal and diseased tissues.
Topics: Animals; Carbohydrate Metabolism; Carbon Isotopes; Glycolysis; Humans; Magnetic Resonance Spectroscopy; Metabolome; Time Factors
PubMed: 30474153
DOI: 10.1002/nbm.4018 -
Cell Stress & Chaperones Nov 2023Plants trigger endoplasmic reticulum (ER) pathways to survive stresses, but the assistance of ER in plant tolerance still needs to be explored. Thus, we selected...
Plants trigger endoplasmic reticulum (ER) pathways to survive stresses, but the assistance of ER in plant tolerance still needs to be explored. Thus, we selected sensitive and tolerant contrasting abiotic stress sorghum varieties to test if they present a degree of tolerance to ER stress. Accordingly, this work evaluated crescent concentrations of tunicamycin (TM µg mL): control (0), lower (0.5), mild (1.5), and higher (2.5) on the initial establishment of sorghum seedlings CSF18 and CSF20. ER stress promoted growth and metabolism reductions, mainly in CSF18, from mild to higher TM. The lowest TM increased SbBiP and SbPDI chaperones, as well as SbbZIP60, and SbbIRE1 gene expressions, but mild and higher TM decreased it. However, CSF20 exhibited higher levels of SbBiP and SbbIRE1 transcripts. It corroborated different metabolic profiles among all TM treatments in CSF18 shoots and similarities between profiles of mild and higher TM in CSF18 roots. Conversely, TM profiles of both shoots and roots of CSF20 overlapped, although it was not complete under low TM treatment. Furthermore, ER stress induced an increase of carbohydrates (dihydroxyacetone in shoots, and cellobiose, maltose, ribose, and sucrose in roots), and organic acids (pyruvic acid in shoots, and butyric and succinic acids in roots) in CSF20, which exhibited a higher degree of ER stress tolerance compared to CSF18 with the root being the most affected plant tissue. Thus, our study provides new insights that may help to understand sorghum tolerance and the ER disturbance as significant contributor for stress adaptation and tolerance engineering.
Topics: Tunicamycin; Sorghum; Molecular Chaperones; Endoplasmic Reticulum; Endoplasmic Reticulum Stress
PubMed: 37775652
DOI: 10.1007/s12192-023-01382-5 -
Cellular and Molecular Life Sciences :... May 2017Carbohydrates are essential nutrients that are used as a primary source of energy. Carbohydrate utilization should be properly controlled, as abnormal regulation of... (Review)
Review
Carbohydrates are essential nutrients that are used as a primary source of energy. Carbohydrate utilization should be properly controlled, as abnormal regulation of carbohydrate metabolism is associated with diseases, such as diabetes, cardiovascular diseases, and stroke. These metabolic syndromes have become a serious problem in developed countries, and there is an increased need for research examining the influence of carbohydrates on animal physiology. Diets enriched in glucose, a major carbohydrate, are also associated with accelerated aging in several model organisms, including yeast and Caenorhabditis elegans (C. elegans). Genetic factors that mediate the effects of high glucose diets on aging have been identified during the last decade, mostly through the use of C. elegans. In this review, we describe studies that determine the effects of carbohydrate-enriched diets on aging by focusing on the mechanisms through which evolutionarily conserved pathways mediate the lifespan-altering effects of glucose in C. elegans. These include the insulin/insulin-like growth factor-1, sterol-regulatory element-binding protein, and AMP-activated protein kinase signaling pathways. We also discuss the effects of various carbohydrates and carbohydrate-derived metabolites on aging in model organisms and cultured mammalian cells. Finally, we discuss how dietary carbohydrates influence health and aging in humans.
Topics: AMP-Activated Protein Kinases; Aging; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Diet, Carbohydrate Loading; Dietary Carbohydrates; Forkhead Transcription Factors; Glucose; Humans; Insulin; Longevity; Metabolic Networks and Pathways; Reactive Oxygen Species; Sterol Regulatory Element Binding Proteins; Transcription Factors
PubMed: 27942749
DOI: 10.1007/s00018-016-2432-6 -
FEBS Letters Sep 2017The biosynthesis of plasmalogens in anaerobic bacteria differs fundamentally from that in animal cells. Firstly, the formation of the alk-1'-enyl ether bond in animal... (Review)
Review
The biosynthesis of plasmalogens in anaerobic bacteria differs fundamentally from that in animal cells. Firstly, the formation of the alk-1'-enyl ether bond in animal cells is oxygen dependent. Secondly, the first step in plasmalogen formation in animal cells is an acylation of dihydroxyacetone phosphate, which has been ruled out as a precursor in anaerobes. In bacteria the alk-1'-enyl ether bond is formed after the fully formed acyl glycerolipids are synthesized. Evidence will be presented for the conversion of the sn-1 acyl-linked chain to an O-alk-1'-enyl ether by an as yet unknown mechanism.
Topics: Acylation; Anaerobiosis; Animals; Clostridium beijerinckii; Dihydroxyacetone Phosphate; Plasmalogens
PubMed: 28617934
DOI: 10.1002/1873-3468.12714