scholarly journals Novel insights into development of diabetic bladder disorder provided by metabolomic analysis of the rat nondiabetic and diabetic detrusor and urothelial layer

2016 ◽  
Vol 311 (2) ◽  
pp. E471-E479 ◽  
Author(s):  
Yi Wang ◽  
Gary G. Deng ◽  
Kelvin P. Davies
Keyword(s):  
Degradation Products ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Branched Chain Amino Acid ◽  
The Tca Cycle ◽  
Glycation End Products ◽  
Markers Of Oxidative Stress ◽  
Branched Chain ◽  
Diabetic Bladder ◽  
Bladder Disorder

There are at present no published studies providing a global overview of changes in bladder metabolism resulting from diabetes. Such studies have the potential to provide mechanistic insight into the development of diabetic bladder disorder (DBD). In the present study, we compared the metabolome of detrusor and urothelial layer in a 1-mo streptozotocin-induced rat model of type 1 diabetes with nondiabetic controls. Our studies revealed that diabetes caused both common and differential changes in the detrusor and urothelial layer's metabolome. Diabetes resulted in similar changes in the levels of previously described diabetic markers in both tissues, such as glucose, lactate, 2-hydroxybutyrate, branched-chain amino acid degradation products, bile acids, and 1,5-anhydroglucitol, as well as markers of oxidative stress. In the detrusor (but not the urothelial layer), diabetes caused activation of the pentose-phosphate and polyol pathways, concomitant with a reduction in the TCA cycle and β-oxidation. Changes in detrusor energy-generating pathways resulted in an accumulation of sorbitol that, through generation of advanced glycation end products, is likely to play a central role in the development of DBD. In the diabetic urothelial layer there was decreased flux of glucose via glycolysis and changes in lipid metabolism, particularly prostaglandin synthesis, which also potentially contributes to detrusor dysfunction.

scholarly journals Branched-chain amino acid catabolism depends on GRXS15 through mitochondrial lipoyl cofactor homeostasis

2020 ◽  
Author(s):  
Anna Moseler ◽  
Inga Kruse ◽  
Andrew E. Maclean ◽  
Luca Pedroletti ◽  
Stephan Wagner ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Degradation Products ◽  
Tca Cycle ◽  
Cluster Assembly ◽  
Amino Acid Catabolism ◽  
Metabolic Defects ◽  
Branched Chain Amino Acid ◽  
Branched Chain ◽  
Dependent Processes

AbstractIron-sulfur (Fe-S) clusters are ubiquitous cofactors in all life and are used in a wide array of diverse biological processes, including electron transfer chains and several metabolic pathways. Biosynthesis machineries for Fe-S clusters exist in plastids, the cytosol and mitochondria. A single monothiol glutaredoxin (GRX) has been shown to be involved in Fe-S cluster assembly in mitochondria of yeast and mammals. In plants, the role of the mitochondrial homologue GRXS15 has only partially been characterized. Arabidopsis grxs15 null mutants are not viable, but mutants complemented with the variant GRXS15 K83A develop with a dwarf phenotype. In an in-depth metabolic analysis, we show that most Fe-S cluster-dependent processes are not affected, including biotin biosynthesis, molybdenum cofactor biosynthesis and the electron transport chain. Instead, we observed an increase in most TCA cycle intermediates and amino acids, especially pyruvate, 2-oxoglutarate, glycine and branched-chain amino acids (BCAAs). The most pronounced accumulation occurred in branched-chain α-keto acids (BCKAs), the first degradation products resulting from deamination of BCAAs. In wild-type plants, pyruvate, 2-oxoglutarate, glycine and BCKAs are all metabolized through decarboxylation by four mitochondrial lipoyl cofactor-dependent dehydrogenase complexes. Because these enzyme complexes are very abundant and the biosynthesis of the lipoyl cofactor depends on continuous Fe-S cluster supply to lipoyl synthase, this could explain why lipoyl cofactor-dependent processes are most sensitive to restricted Fe-S supply in GRXS15 K83A mutants.One-sentence summaryDeficiency in GRXS15 restricts protein lipoylation and causes metabolic defects in lipoyl cofactor-dependent dehydrogenase complexes, with branched-chain amino acid catabolism as dominant bottleneck.

α-Aminoadipate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2327-2334 ◽  
Author(s):  
Takashi Miyazaki ◽  
Junichi Miyazaki ◽  
Hisakazu Yamane ◽  
Makoto Nishiyama
Keyword(s):  
Thermus Thermophilus ◽  
Tca Cycle ◽  
Thermophilic Bacterium ◽  
Multiple Roles ◽  
Lysine Biosynthesis ◽  
Lag Phase ◽  
Gene Encoding ◽  
Branched Chain Amino Acid ◽  
The Tca Cycle ◽  
Branched Chain

The extremely thermophilic bacterium Thermus thermophilus HB27 synthesizes lysine through α-aminoadipate (AAA). In this study, a T. thermophilus gene encoding the enzyme that catalyses transamination of AAA was cloned as a mammalian kynurenine/AAA aminotransferase (Kat2) gene homologue. A T. thermophilus mutant with disruption of the Kat2 homologue required a longer lag phase for growth and showed slower growth in minimal medium. Furthermore, addition of AAA or lysine shortened the lag phase and improved the growth rate. The Kat2 homologue was therefore termed lysN. LysN recognizes not only 2-oxoadipate, an intermediate of lysine biosynthesis, but also 2-oxoisocaproate, 2-oxoisovalerate and 2-oxo-3-methylvalerate, intermediates of leucine, valine and isoleucine biosyntheses, respectively, along with oxaloacetate, a compound in the TCA cycle, as an amino acceptor. These results suggest multiple roles of LysN in several cellular metabolic pathways including lysine and branched-chain amino acid biosyntheses.

scholarly journals Ammonia inhibits energy metabolism in astrocytes in a rapid and glutamate dehydrogenase 2-dependent manner

2020 ◽  
Vol 13 (10) ◽  
pp. dmm047134
Author(s):  
Leonie Drews ◽  
Marcel Zimmermann ◽  
Philipp Westhoff ◽  
Dominik Brilhaus ◽  
Rebecca E. Poss ◽  
...  
Keyword(s):  
Amino Acids ◽  
Energy Metabolism ◽  
Glutamate Dehydrogenase ◽  
Mitochondrial Respiration ◽  
Tca Cycle ◽  
Dependent Manner ◽  
Independent Manner ◽  
The Tca Cycle ◽  
Branched Chain ◽  
Tca Cycle Intermediates

ABSTRACTAstrocyte dysfunction is a primary factor in hepatic encephalopathy (HE) impairing neuronal activity under hyperammonemia. In particular, the early events causing ammonia-induced toxicity to astrocytes are not well understood. Using established cellular HE models, we show that mitochondria rapidly undergo fragmentation in a reversible manner upon hyperammonemia. Further, in our analyses, within a timescale of minutes, mitochondrial respiration and glycolysis were hampered, which occurred in a pH-independent manner. Using metabolomics, an accumulation of glucose and numerous amino acids, including branched chain amino acids, was observed. Metabolomic tracking of 15N-labeled ammonia showed rapid incorporation of 15N into glutamate and glutamate-derived amino acids. Downregulating human GLUD2 [encoding mitochondrial glutamate dehydrogenase 2 (GDH2)], inhibiting GDH2 activity by SIRT4 overexpression, and supplementing cells with glutamate or glutamine alleviated ammonia-induced inhibition of mitochondrial respiration. Metabolomic tracking of 13C-glutamine showed that hyperammonemia can inhibit anaplerosis of tricarboxylic acid (TCA) cycle intermediates. Contrary to its classical anaplerotic role, we show that, under hyperammonemia, GDH2 catalyzes the removal of ammonia by reductive amination of α-ketoglutarate, which efficiently and rapidly inhibits the TCA cycle. Overall, we propose a critical GDH2-dependent mechanism in HE models that helps to remove ammonia, but also impairs energy metabolism in mitochondria rapidly.

scholarly journals BCAT1 affects mitochondrial metabolism independently of leucine transamination in activated human macrophages

2020 ◽  
Vol 133 (22) ◽  
pp. jcs247957
Author(s):  
Jeong-Hun Ko ◽  
Antoni Olona ◽  
Adonia E. Papathanassiu ◽  
Norzawani Buang ◽  
Kwon-Sik Park ◽  
...  
Keyword(s):  
Macrophage Activation ◽  
Polarization State ◽  
Tca Cycle ◽  
Metabolic Adaptation ◽  
Human Macrophages ◽  
Relative Contribution ◽  
The Tca Cycle ◽  
Nutrient Consumption ◽  
Anti Oxidant ◽  
Branched Chain

ABSTRACTIn response to environmental stimuli, macrophages change their nutrient consumption and undergo an early metabolic adaptation that progressively shapes their polarization state. During the transient, early phase of pro-inflammatory macrophage activation, an increase in tricarboxylic acid (TCA) cycle activity has been reported, but the relative contribution of branched-chain amino acid (BCAA) leucine remains to be determined. Here, we show that glucose but not glutamine is a major contributor of the increase in TCA cycle metabolites during early macrophage activation in humans. We then show that, although uptake of BCAAs is not altered, their transamination by BCAT1 is increased following 8 h lipopolysaccharide (LPS) stimulation. Of note, leucine is not metabolized to integrate into the TCA cycle in basal or stimulated human macrophages. Surprisingly, the pharmacological inhibition of BCAT1 reduced glucose-derived itaconate, α-ketoglutarate and 2-hydroxyglutarate levels without affecting succinate and citrate levels, indicating a partial inhibition of the TCA cycle. This indirect effect is associated with NRF2 (also known as NFE2L2) activation and anti-oxidant responses. These results suggest a moonlighting role of BCAT1 through redox-mediated control of mitochondrial function during early macrophage activation.

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.

scholarly journals Highly flexible metabolism of the marine euglenozoan protist Diplonema papillatum

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ingrid Škodová-Sveráková ◽  
Kristína Záhonová ◽  
Valéria Juricová ◽  
Maksym Danchenko ◽  
Martin Moos ◽  
...  
Keyword(s):  
Tca Cycle ◽  
Primary Energy ◽  
Pentose Phosphate ◽  
Metabolic Reprogramming ◽  
Metabolic Flexibility ◽  
Low Oxygen ◽  
Ecological Functions ◽  
Carbon Availability ◽  
The Tca Cycle ◽  
Transcriptomic Level

Abstract Background The phylum Euglenozoa is a group of flagellated protists comprising the diplonemids, euglenids, symbiontids, and kinetoplastids. The diplonemids are highly abundant and speciose, and recent tools have rendered the best studied representative, Diplonema papillatum, genetically tractable. However, despite the high diversity of diplonemids, their lifestyles, ecological functions, and even primary energy source are mostly unknown. Results We designed a metabolic map of D. papillatum cellular bioenergetic pathways based on the alterations of transcriptomic, proteomic, and metabolomic profiles obtained from cells grown under different conditions. Comparative analysis in the nutrient-rich and nutrient-poor media, as well as the absence and presence of oxygen, revealed its capacity for extensive metabolic reprogramming that occurs predominantly on the proteomic rather than the transcriptomic level. D. papillatum is equipped with fundamental metabolic routes such as glycolysis, gluconeogenesis, TCA cycle, pentose phosphate pathway, respiratory complexes, β-oxidation, and synthesis of fatty acids. Gluconeogenesis is uniquely dominant over glycolysis under all surveyed conditions, while the TCA cycle represents an eclectic combination of standard and unusual enzymes. Conclusions The identification of conventional anaerobic enzymes reflects the ability of this protist to survive in low-oxygen environments. Furthermore, its metabolism quickly reacts to restricted carbon availability, suggesting a high metabolic flexibility of diplonemids, which is further reflected in cell morphology and motility, correlating well with their extreme ecological valence.

THE OXIDATIVE METABOLISM OF RHODOTORULA GRACILIS

1958 ◽  
Vol 4 (3) ◽  
pp. 205-213 ◽  
Author(s):  
John H. Litchfield ◽  
Z. John Ordal
Keyword(s):  
Oxidative Metabolism ◽  
Dicarboxylic Acids ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Cell Suspensions ◽  
Resting Cell ◽  
The Tca Cycle ◽  
Rhodotorula Gracilis ◽  
Oxidation Of Glucose

The oxidative metabolism of Rhodolorula gracilis NRRL Y-1091 was investigated. Data was presented showing the oxidation of glucose, acetate, pyruvate, xylose, D- and L-arabinose, by both glucose- and xylose-grown cells. Gluconate was oxidized by the glucose-grown cells, while ribose was oxidized by the xylose-grown cells. Cell-free extracts of glucose-grown cells oxidized glucose, gluconate, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, and ribose-5-phosphate. Pentose phosphate was demonstrated as a product of glucose-6-phosphate oxidation. Resting-cell suspensions were unable to oxidize citrate, but they oxidized the dicarboxylic acids of the TCA cycle. Citrate was detected as a product of the oxidation of acetate, pyruvate, and malate in the presence of fluoroacetate. Cell-free extracts of glucose-grown cells oxidized citrate, isocitrate, and the dicarboxylic acids of the TCA cycle.

scholarly journals BCKDK regulates the TCA cycle through PDC to ensure embryonic development in the absence of PDK family

2020 ◽  
Author(s):  
Lia Heinemann-Yerushalmi ◽  
Lital Bentovim ◽  
Neta Felsenthal ◽  
Ron Carmel Vinestock ◽  
Nofar Michaeli ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Tca Cycle ◽  
Bioinformatic Analysis ◽  
Compensatory Mechanism ◽  
The Tca Cycle ◽  
Early Embryonic Lethality ◽  
Branched Chain ◽  
Ketoacid Dehydrogenase

AbstractPyruvate dehydrogenase kinases (PDK1-4) inhibit the TCA cycle by phosphorylating pyruvate dehydrogenase complex (PDC). Here, we show that the PDK family is dispensable for the survival of murine embryonic development and that BCKDK serves as a compensatory mechanism by inactivating PDC.First, we knocked out all fourPdkgenes one by one. Surprisingly,Pdktotal KO embryos developed and were born in expected ratios, but died by postnatal day 4 due to hypoglycemia or ketoacidosis.Finding that PDC was phosphorylated in these embryos suggested that another kinase compensates for the PDK family. Bioinformatic analysis implicated brunch chain ketoacid dehydrogenase kinase (Bckdk), a key regulator of branched chain amino acids (BCAA) catabolism. Indeed, knockout ofBckdkand thePdkfamily led to loss of PDC phosphorylation, increment in PDC activity, elevation of Pyruvate flux into the TCA and early embryonic lethality. These findings reveal a new regulatory crosstalk hardwiring BCAA and glucose catabolic pathways, which feed the TCA cycle.

scholarly journals Accelerated Metabolite Levels of Aerobic Glycolysis and the Pentose Phosphate Pathway Are Required for Efficient Replication of Infectious Spleen and Kidney Necrosis Virus in Chinese Perch Brain Cells

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 440
Author(s):  
Xixi Guo ◽  
Shiwei Wu ◽  
Ningqiu Li ◽  
Qiang Lin ◽  
Lihui Liu ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Late Stage ◽  
Metabolic Pathways ◽  
Aerobic Glycolysis ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Infection Cycle ◽  
Necrosis Virus ◽  
The Tca Cycle ◽  
Chinese Perch

Glucose is a main carbon and energy source for virus proliferation and is usually involved in the glycolysis, pentose phosphate pathway (PPP), and tricarboxylic acid cycle (TCA cycle) pathways. In this study, we investigated the roles of glucose-related metabolic pathways during the replication of infectious spleen and kidney necrosis virus (ISKNV), which has caused serious economic losses in the cultured Chinese perch (Siniperca chuatsi) industry. We found that ISKNV infection enhanced the metabolic pathways of the PPP and the TCA cycle at the early stage of the ISKNV infection cycle and enhanced the glycolysis pathway at the late stage of the ISKNV infection cycle though the comprehensive analysis of transcriptomics, proteomics, and metabolomics. The advanced results proved that ISKNV replication induced upregulation of aerobic glycolysis at the late stage of ISKNV infection cycle and aerobic glycolysis were required for ISKNV multiplication. In addition, the PPP, providing nucleotide biosynthesis, was also required for ISKNV multiplication. However, the TCA cycle involving glucose was not important and necessary for ISKNV multiplication. The results reported here provide new insights into viral pathogenesis mechanism of metabolic shift, as well as antiviral treatment strategies.

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