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Bischoff ME, Shamsaei B, Yang J, Secic D, Vemuri B, Reisz JA, D'Alessandro A, Bartolacci C, Adamczak R, Schmidt L, Wang J, Martines A, Biesiada J, Vest KE, Scaglioni PP, Plas DR, Patra KC, Gulati S, Figueroa JAL, Meller J, Cunningham JT, Czyzyk-Krzeska MF. Copper drives remodeling of metabolic state and progression of clear cell renal cell carcinoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.16.575895. [PMID: 38293110 PMCID: PMC10827129 DOI: 10.1101/2024.01.16.575895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Copper (Cu) is an essential trace element required for mitochondrial respiration. Late-stage clear cell renal cell carcinoma (ccRCC) accumulates Cu and allocates it to mitochondrial cytochrome c oxidase. We show that Cu drives coordinated metabolic remodeling of bioenergy, biosynthesis and redox homeostasis, promoting tumor growth and progression of ccRCC. Specifically, Cu induces TCA cycle-dependent oxidation of glucose and its utilization for glutathione biosynthesis to protect against H 2 O 2 generated during mitochondrial respiration, therefore coordinating bioenergy production with redox protection. scRNA-seq determined that ccRCC progression involves increased expression of subunits of respiratory complexes, genes in glutathione and Cu metabolism, and NRF2 targets, alongside a decrease in HIF activity, a hallmark of ccRCC. Spatial transcriptomics identified that proliferating cancer cells are embedded in clusters of cells with oxidative metabolism supporting effects of metabolic states on ccRCC progression. Our work establishes novel vulnerabilities with potential for therapeutic interventions in ccRCC. Accumulation of copper is associated with progression and relapse of ccRCC and drives tumor growth.Cu accumulation and allocation to cytochrome c oxidase (CuCOX) remodels metabolism coupling energy production and nucleotide biosynthesis with maintenance of redox homeostasis.Cu induces oxidative phosphorylation via alterations in the mitochondrial proteome and lipidome necessary for the formation of the respiratory supercomplexes. Cu stimulates glutathione biosynthesis and glutathione derived specifically from glucose is necessary for survival of Cu Hi cells. Biosynthesis of glucose-derived glutathione requires activity of glutamyl pyruvate transaminase 2, entry of glucose-derived pyruvate to mitochondria via alanine, and the glutamate exporter, SLC25A22. Glutathione derived from glucose maintains redox homeostasis in Cu-treated cells, reducing Cu-H 2 O 2 Fenton-like reaction mediated cell death. Progression of human ccRCC is associated with gene expression signature characterized by induction of ETC/OxPhos/GSH/Cu-related genes and decrease in HIF/glycolytic genes in subpopulations of cancer cells. Enhanced, concordant expression of genes related to ETC/OxPhos, GSH, and Cu characterizes metabolically active subpopulations of ccRCC cells in regions adjacent to proliferative subpopulations of ccRCC cells, implicating oxidative metabolism in supporting tumor growth.
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Danmaliki GI, Yu S, Braun S, Zhao YY, Moore J, Fahlman RP, West FG, Hwang PM. Cost-effective selective deuteration of aromatic amino acid residues produces long-lived solution 1H NMR magnetization in proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 353:107499. [PMID: 37307676 DOI: 10.1016/j.jmr.2023.107499] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/24/2023] [Accepted: 06/01/2023] [Indexed: 06/14/2023]
Abstract
Solution NMR studies of large proteins are hampered by rapid signal decay due to short-range dipolar 1H-1H and 1H-13C interactions. These are attenuated by rapid rotation in methyl groups and by deuteration (2H), so selective 1H,13C-isotope labelling of methyl groups in otherwise perdeuterated proteins, combined with methyl transverse relaxation optimized spectroscopy (methyl-TROSY), is now standard for solution NMR of large protein systems > 25 kDa. For non-methyl positions, long-lived magnetization can be introduced as isolated 1H-12C groups. We have developed a cost-effective chemical synthesis for producing selectively deuterated phenylpyruvate and hydroxyphenylpyruvate. Feeding these amino acid precursors to E. coli in D2O, along with selectively deuterated anthranilate and unlabeled histidine, results in isolated and long-lived 1H magnetization in the aromatic rings of Phe (HD, HZ), Tyr (HD), Trp (HH2, HE3) and His (HD2 and HE1). We are additionally able to obtain stereoselective deuteration of Asp, Asn, and Lys amino acid residues using unlabeled glucose and fumarate as carbon sources and oxalate and malonate as metabolic inhibitors. Combining these approaches produces isolated 1H-12C groups in Phe, Tyr, Trp, His, Asp, Asn, and Lys in a perdeuterated background, which is compatible with standard 1H-13C labeling of methyl groups in Ala, Ile, Leu, Val, Thr, Met. We show that isotope labeling of Ala is improved using the transaminase inhibitor L-cycloserine, and labeling of Thr is improved through addition of Cys and Met, which are known inhibitors of homoserine dehydrogenase. We demonstrate the creation of long-lived 1H NMR signals in most amino acid residues using our model system, the WW domain of human Pin1, as well as the bacterial outer membrane protein PagP.
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Affiliation(s)
- Gaddafi I Danmaliki
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Shaohui Yu
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Shelly Braun
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Yuan Y Zhao
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Jack Moore
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Frederick G West
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Peter M Hwang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2R3, Canada.
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3
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Gotep JG, Sabo SY, Makama S, Gyang J, Pwajok Choji TP, Uguru MO, Okwuasaba FK. Effect of oral administration of Fadogia cienkowskii Shweinf. (Rubiaceae) ethanol root extract on some semen parameters, testes, epididymis, liver and kidney of male albino rats. SCIENTIFIC AFRICAN 2023. [DOI: 10.1016/j.sciaf.2023.e01637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023] Open
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4
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Giulivi C, Wang JY, Hagerman RJ. Artificial neural network applied to fragile X-associated tremor/ataxia syndrome stage diagnosis based on peripheral mitochondrial bioenergetics and brain imaging outcomes. Sci Rep 2022; 12:21382. [PMID: 36496525 PMCID: PMC9741636 DOI: 10.1038/s41598-022-25615-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
No proven prognosis is available for the neurodegenerative disorder fragile X-associated tremor/ataxia syndrome (FXTAS). Artificial neural network analyses (ANN) were used to predict FXTAS progression using data from 127 adults (noncarriers and FMR1 premutation carriers with and without FXTAS) with five outcomes from brain MRI imaging and 22 peripheral bioenergetic outcomes from two cell types. Diagnosis accuracy by ANN predictions ranged from 41.7 to 86.3% (depending on the algorithm used), and those misclassified usually presented a higher FXTAS stage. ANN prediction of FXTAS stages was based on a combination of two imaging findings (white matter hyperintensity and whole-brain volumes adjusted for intracranial volume) and four bioenergetic outcomes. Those at Stage 3 vs. 0-2 showed lower mitochondrial mass, higher oxidative stress, and an altered electron transfer consistent with mitochondrial unfolded protein response activation. Those at Stages 4-5 vs. 3 had higher oxidative stress and glycerol-3-phosphate-linked ATP production, suggesting that targeting mGPDH activity may prevent a worse prognosis. This was confirmed by the bioenergetic improvement of inhibiting mGPDH with metformin in affected fibroblasts. ANN supports the prospect of an unbiased molecular definition in diagnosing FXTAS stages while identifying potential targets for personalized medicine.
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Affiliation(s)
- Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
- MIND Institute, University of California at Davis Medical Center, Sacramento, CA, USA.
| | - Jun Yi Wang
- MIND Institute, University of California at Davis Medical Center, Sacramento, CA, USA
- Center for Mind and Brain, University of California Davis, Davis, CA, USA
| | - Randi J Hagerman
- MIND Institute, University of California at Davis Medical Center, Sacramento, CA, USA
- Department of Pediatrics, University of California at Davis Medical Center, Sacramento, CA, USA
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Cirino G, Szabo C, Papapetropoulos A. Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs. Physiol Rev 2022; 103:31-276. [DOI: 10.1152/physrev.00028.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.
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Affiliation(s)
- Giuseppe Cirino
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Naples, Italy
| | - Csaba Szabo
- Chair of Pharmacology, Section of Medicine, University of Fribourg, Switzerland
| | - Andreas Papapetropoulos
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece & Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Greece
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Gain G, Vega de Luna F, Cordoba J, Perez E, Degand H, Morsomme P, Thiry M, Baurain D, Pierangelini M, Cardol P. Trophic state alters the mechanism whereby energetic coupling between photosynthesis and respiration occurs in Euglena gracilis. THE NEW PHYTOLOGIST 2021; 232:1603-1617. [PMID: 34392544 PMCID: PMC9292222 DOI: 10.1111/nph.17677] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
The coupling between mitochondrial respiration and photosynthesis plays an important role in the energetic physiology of green plants and some secondary-red photosynthetic eukaryotes (diatoms), allowing an efficient CO2 assimilation and optimal growth. Using the flagellate Euglena gracilis, we first tested if photosynthesis-respiration coupling occurs in this species harbouring secondary green plastids (i.e. originated from an endosymbiosis between a green alga and a phagotrophic euglenozoan). Second, we tested how the trophic state (mixotrophy and photoautotrophy) of the cell alters the mechanisms involved in the photosynthesis-respiration coupling. Energetic coupling between photosynthesis and respiration was determined by testing the effect of respiratory inhibitors on photosynthesis, and measuring the simultaneous variation of photosynthesis and respiration rates as a function of temperature (i.e. thermal response curves). The mechanism involved in the photosynthesis-respiration coupling was assessed by combining proteomics, biophysical and cytological analyses. Our work shows that there is photosynthesis-respiration coupling and membrane contacts between mitochondria and chloroplasts in E. gracilis. However, whereas in mixotrophy adjustment of the chloroplast ATP/NADPH ratio drives the interaction, in photoautotrophy the coupling is conditioned by CO2 limitation and photorespiration. This indicates that maintenance of photosynthesis-respiration coupling, through plastic metabolic responses, is key to E. gracilis functioning under changing environmental conditions.
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Affiliation(s)
- Gwenaëlle Gain
- InBioS – PhytoSYSTEMSLaboratoire de Génétique et Physiologie des MicroalguesULiègeLiègeB‐4000Belgium
| | - Félix Vega de Luna
- InBioS – PhytoSYSTEMSLaboratoire de Génétique et Physiologie des MicroalguesULiègeLiègeB‐4000Belgium
| | - Javier Cordoba
- InBioS – PhytoSYSTEMSLaboratoire de Génétique et Physiologie des MicroalguesULiègeLiègeB‐4000Belgium
| | - Emilie Perez
- InBioS – PhytoSYSTEMSLaboratoire de Génétique et Physiologie des MicroalguesULiègeLiègeB‐4000Belgium
| | - Hervé Degand
- Louvain Institute of Biomolecular Science and Technology (LIBST)UCLouvainLouvain‐la‐NeuveB‐1348Belgium
| | - Pierre Morsomme
- Louvain Institute of Biomolecular Science and Technology (LIBST)UCLouvainLouvain‐la‐NeuveB‐1348Belgium
| | - Marc Thiry
- Laboratoire de Biologie Cellulaire et TissulaireGiga‐NeurosciencesULiègeLiègeB‐4000Belgium
| | - Denis Baurain
- InBioS – PhytoSYSTEMSEukaryotic PhylogenomicsULiègeLiègeB‐4000Belgium
| | - Mattia Pierangelini
- InBioS – PhytoSYSTEMSLaboratoire de Génétique et Physiologie des MicroalguesULiègeLiègeB‐4000Belgium
| | - Pierre Cardol
- InBioS – PhytoSYSTEMSLaboratoire de Génétique et Physiologie des MicroalguesULiègeLiègeB‐4000Belgium
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Le XH, Lee CP, Millar AH. The mitochondrial pyruvate carrier (MPC) complex mediates one of three pyruvate-supplying pathways that sustain Arabidopsis respiratory metabolism. THE PLANT CELL 2021; 33:2776-2793. [PMID: 34137858 PMCID: PMC8408480 DOI: 10.1093/plcell/koab148] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/19/2021] [Indexed: 05/03/2023]
Abstract
Malate oxidation by plant mitochondria enables the generation of both oxaloacetate and pyruvate for tricarboxylic acid (TCA) cycle function, potentially eliminating the need for pyruvate transport into mitochondria in plants. Here, we show that the absence of the mitochondrial pyruvate carrier 1 (MPC1) causes the co-commitment loss of its putative orthologs, MPC3/MPC4, and eliminates pyruvate transport into Arabidopsis thaliana mitochondria, proving it is essential for MPC complex function. While the loss of either MPC or mitochondrial pyruvate-generating NAD-malic enzyme (NAD-ME) did not cause vegetative phenotypes, the lack of both reduced plant growth and caused an increase in cellular pyruvate levels, indicating a block in respiratory metabolism, and elevated the levels of branched-chain amino acids at night, a sign of alterative substrate provision for respiration. 13C-pyruvate feeding of leaves lacking MPC showed metabolic homeostasis was largely maintained except for alanine and glutamate, indicating that transamination contributes to the restoration of the metabolic network to an operating equilibrium by delivering pyruvate independently of MPC into the matrix. Inhibition of alanine aminotransferases when MPC1 is absent resulted in extremely retarded phenotypes in Arabidopsis, suggesting all pyruvate-supplying enzymes work synergistically to support the TCA cycle for sustained plant growth.
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Affiliation(s)
- Xuyen H. Le
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth 6009, Australia
| | - Chun-Pong Lee
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth 6009, Australia
| | - A. Harvey Millar
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth 6009, Australia
- Author for correspondence:
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8
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Chavan SP, Kawale SA, Patil NB, Kalbhor DB. Application of allylic amine formation from aziridine-2-ol under Appel reaction condition: Synthesis of N-(tert-butoxycarbonyl)-D-vinyl glycine methyl ester. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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9
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Korenfeld N, Finkel M, Buchshtab N, Bar-Shimon M, Charni-Natan M, Goldstein I. Fasting Hormones Synergistically Induce Amino Acid Catabolism Genes to Promote Gluconeogenesis. Cell Mol Gastroenterol Hepatol 2021; 12:1021-1036. [PMID: 33957303 PMCID: PMC8346669 DOI: 10.1016/j.jcmgh.2021.04.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 12/10/2022]
Abstract
BACKGROUND & AIMS Gluconeogenesis from amino acids (AAs) maintains glucose homeostasis during fasting. Although glucagon is known to regulate AA catabolism, the contribution of other hormones to it and the scope of transcriptional regulation dictating AA catabolism are unknown. We explored the role of the fasting hormones glucagon and glucocorticoids in transcriptional regulation of AA catabolism genes and AA-dependent gluconeogenesis. METHODS We tested the RNA expression of AA catabolism genes and glucose production in primary mouse hepatocytes treated with fasting hormones (glucagon, corticosterone) and feeding hormones (insulin, fibroblast growth factor 19). We analyzed genomic data of chromatin accessibility and chromatin immunoprecipitation in mice and primary mouse hepatocytes. We performed chromatin immunoprecipitation in livers of fasted mice to show binding of cAMP responsive element binding protein (CREB) and the glucocorticoid receptor (GR). RESULTS Fasting induced the expression of 31 genes with various roles in AA catabolism. Of them, 15 were synergistically induced by co-treatment of glucagon and corticosterone. Synergistic gene expression relied on the activity of both CREB and GR and was abolished by treatment with either insulin or fibroblast growth factor 19. Enhancers adjacent to synergistically induced genes became more accessible and were bound by CREB and GR on fasting. Akin to the gene expression pattern, gluconeogenesis from AAs was synergistically induced by glucagon and corticosterone in a CREB- and GR-dependent manner. CONCLUSIONS Transcriptional regulation of AA catabolism genes during fasting is widespread and is driven by glucagon (via CREB) and corticosterone (via GR). Glucose production in hepatocytes is also synergistically augmented, showing that glucagon alone is insufficient in fully activating gluconeogenesis.
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Affiliation(s)
- Noga Korenfeld
- Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel
| | - Maya Finkel
- Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel
| | - Nufar Buchshtab
- Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel
| | - Meirav Bar-Shimon
- Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel
| | - Meital Charni-Natan
- Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel
| | - Ido Goldstein
- Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel.
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10
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Veliova M, Ferreira CM, Benador IY, Jones AE, Mahdaviani K, Brownstein AJ, Desousa BR, Acín-Pérez R, Petcherski A, Assali EA, Stiles L, Divakaruni AS, Prentki M, Corkey BE, Liesa M, Oliveira MF, Shirihai OS. Blocking mitochondrial pyruvate import in brown adipocytes induces energy wasting via lipid cycling. EMBO Rep 2020; 21:e49634. [PMID: 33275313 PMCID: PMC7726774 DOI: 10.15252/embr.201949634] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 09/15/2020] [Accepted: 10/07/2020] [Indexed: 12/20/2022] Open
Abstract
Combined fatty acid esterification and lipolysis, termed lipid cycling, is an ATP‐consuming process that contributes to energy expenditure. Therefore, interventions that stimulate energy expenditure through lipid cycling are of great interest. Here we find that pharmacological and genetic inhibition of the mitochondrial pyruvate carrier (MPC) in brown adipocytes activates lipid cycling and energy expenditure, even in the absence of adrenergic stimulation. We show that the resulting increase in ATP demand elevates mitochondrial respiration coupled to ATP synthesis and fueled by lipid oxidation. We identify that glutamine consumption and the Malate‐Aspartate Shuttle are required for the increase in Energy Expenditure induced by MPC inhibition in Brown Adipocytes (MAShEEBA). We thus demonstrate that energy expenditure through enhanced lipid cycling can be activated in brown adipocytes by decreasing mitochondrial pyruvate availability. We present a new mechanism to increase energy expenditure and fat oxidation in brown adipocytes, which does not require adrenergic stimulation of mitochondrial uncoupling.
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Affiliation(s)
- Michaela Veliova
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Caroline M Ferreira
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Ilan Y Benador
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, USA
| | - Anthony E Jones
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kiana Mahdaviani
- Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, USA
| | - Alexandra J Brownstein
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Molecular Cellular Integrative Physiology, University of California, Los Angeles, CA, USA
| | - Brandon R Desousa
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Rebeca Acín-Pérez
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Anton Petcherski
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Essam A Assali
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Department of Clinical Biochemistry, School of Medicine, Ben Gurion University of The Negev, Beer-Sheva, Israel
| | - Linsey Stiles
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Marc Prentki
- Department of Nutrition, , Université de Montréal, Montreal Diabetes Research Center and CRCHUM, Montréal, QC, Canada
| | - Barbara E Corkey
- Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, USA
| | - Marc Liesa
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Marcus F Oliveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Orian S Shirihai
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, USA
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Rahman MA, Glasgow JN, Nadeem S, Reddy VP, Sevalkar RR, Lancaster JR, Steyn AJC. The Role of Host-Generated H 2S in Microbial Pathogenesis: New Perspectives on Tuberculosis. Front Cell Infect Microbiol 2020; 10:586923. [PMID: 33330130 PMCID: PMC7711268 DOI: 10.3389/fcimb.2020.586923] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/13/2020] [Indexed: 12/14/2022] Open
Abstract
For centuries, hydrogen sulfide (H2S) was considered primarily as a poisonous gas and environmental hazard. However, with the discovery of prokaryotic and eukaryotic enzymes for H2S production, breakdown, and utilization, H2S has emerged as an important signaling molecule in a wide range of physiological and pathological processes. Hence, H2S is considered a gasotransmitter along with nitric oxide (•NO) and carbon monoxide (CO). Surprisingly, despite having overlapping functions with •NO and CO, the role of host H2S in microbial pathogenesis is understudied and represents a gap in our knowledge. Given the numerous reports that followed the discovery of •NO and CO and their respective roles in microbial pathogenesis, we anticipate a rapid increase in studies that further define the importance of H2S in microbial pathogenesis, which may lead to new virulence paradigms. Therefore, this review provides an overview of sulfide chemistry, enzymatic production of H2S, and the importance of H2S in metabolism and immunity in response to microbial pathogens. We then describe our current understanding of the role of host-derived H2S in tuberculosis (TB) disease, including its influences on host immunity and bioenergetics, and on Mycobacterium tuberculosis (Mtb) growth and survival. Finally, this review discusses the utility of H2S-donor compounds, inhibitors of H2S-producing enzymes, and their potential clinical significance.
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Affiliation(s)
| | - Joel N Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sajid Nadeem
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Vineel P Reddy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ritesh R Sevalkar
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jack R Lancaster
- Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Adrie J C Steyn
- Africa Health Research Institute, Durban, South Africa.,Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, United States
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12
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Gifford JL, Nguyen WN, de Koning L, Seiden-Long I. Stabilizing specimens for routine ammonia testing in the clinical laboratory. Clin Chim Acta 2018; 478:37-43. [DOI: 10.1016/j.cca.2017.12.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/21/2017] [Accepted: 12/15/2017] [Indexed: 01/09/2023]
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Lee J, Kang E, Kobayashi S, Homma T, Sato H, Seo H, Fujii J. The viability of primary hepatocytes is maintained under a low cysteine-glutathione redox state with a marked elevation in ophthalmic acid production. Exp Cell Res 2017; 361:178-191. [DOI: 10.1016/j.yexcr.2017.10.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 10/17/2017] [Accepted: 10/20/2017] [Indexed: 12/22/2022]
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14
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Sands SA, LeVine SM. Substrate reduction therapy for Krabbe's disease. J Neurosci Res 2017; 94:1261-72. [PMID: 27638608 DOI: 10.1002/jnr.23791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/19/2016] [Accepted: 05/18/2016] [Indexed: 01/30/2023]
Abstract
Krabbe's disease (KD) is a lysosomal storage disorder in which galactosylceramide, a major glycosphingolipid of myelin, and psychosine (galactose-sphingosine) cannot be adequately metabolized because of a deficiency in galactosylceramidase. Substrate reduction therapy (SRT) has been tested in preclinical studies. The premise of SRT is to reduce the synthesis of substrates that are not adequately digested so that the substrate burden is lowered, resulting in less accumulation of unmetabolized material. SRT is used for Gaucher's disease, in which inhibitors of the terminal biosynthetic step are used. Unfortunately, an inhibitor for the final step of galactosylceramide biosynthesis, i.e., UDP glycosyltransferase 8 (a.k.a. UDP-galactose ceramide galactosyltransferase), has not been found. Approaches that inhibit an earlier biosynthetic step or that lessen the substrate burden by other means, such as genetic manipulations, have been tested in the twitcher mouse model of KD. Either as a stand-alone therapy or in combination with other approaches, SRT slowed the disease course, indicating that this approach has potential therapeutic value. For instance, in individuals with adult-onset disease, SRT theoretically could lessen the production of substrates so that residual enzymatic activity could adequately manage the lower substrate burden. In more severe forms of disease, SRT theoretically could be part of a combination therapy. However, SRT has the potential to impair normal function by reducing the synthesis of galactosylceramide to levels that impede myelin function, or SRT could have other deleterious effects. Thus, multiple issues need to be resolved before this approach is ready for testing in humans. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Scott A Sands
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Steven M LeVine
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas.
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Szabo C, Papapetropoulos A. International Union of Basic and Clinical Pharmacology. CII: Pharmacological Modulation of H 2S Levels: H 2S Donors and H 2S Biosynthesis Inhibitors. Pharmacol Rev 2017; 69:497-564. [PMID: 28978633 PMCID: PMC5629631 DOI: 10.1124/pr.117.014050] [Citation(s) in RCA: 273] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Over the last decade, hydrogen sulfide (H2S) has emerged as an important endogenous gasotransmitter in mammalian cells and tissues. Similar to the previously characterized gasotransmitters nitric oxide and carbon monoxide, H2S is produced by various enzymatic reactions and regulates a host of physiologic and pathophysiological processes in various cells and tissues. H2S levels are decreased in a number of conditions (e.g., diabetes mellitus, ischemia, and aging) and are increased in other states (e.g., inflammation, critical illness, and cancer). Over the last decades, multiple approaches have been identified for the therapeutic exploitation of H2S, either based on H2S donation or inhibition of H2S biosynthesis. H2S donation can be achieved through the inhalation of H2S gas and/or the parenteral or enteral administration of so-called fast-releasing H2S donors (salts of H2S such as NaHS and Na2S) or slow-releasing H2S donors (GYY4137 being the prototypical compound used in hundreds of studies in vitro and in vivo). Recent work also identifies various donors with regulated H2S release profiles, including oxidant-triggered donors, pH-dependent donors, esterase-activated donors, and organelle-targeted (e.g., mitochondrial) compounds. There are also approaches where existing, clinically approved drugs of various classes (e.g., nonsteroidal anti-inflammatories) are coupled with H2S-donating groups (the most advanced compound in clinical trials is ATB-346, an H2S-donating derivative of the non-steroidal anti-inflammatory compound naproxen). For pharmacological inhibition of H2S synthesis, there are now several small molecule compounds targeting each of the three H2S-producing enzymes cystathionine-β-synthase (CBS), cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase. Although many of these compounds have their limitations (potency, selectivity), these molecules, especially in combination with genetic approaches, can be instrumental for the delineation of the biologic processes involving endogenous H2S production. Moreover, some of these compounds (e.g., cell-permeable prodrugs of the CBS inhibitor aminooxyacetate, or benserazide, a potentially repurposable CBS inhibitor) may serve as starting points for future clinical translation. The present article overviews the currently known H2S donors and H2S biosynthesis inhibitors, delineates their mode of action, and offers examples for their biologic effects and potential therapeutic utility.
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Affiliation(s)
- Csaba Szabo
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas (C.S.); Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Zografou, Greece (A.P.); and Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece (A.P.)
| | - Andreas Papapetropoulos
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas (C.S.); Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Zografou, Greece (A.P.); and Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece (A.P.)
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16
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Kobayashi S, Lee J, Takao T, Fujii J. Increased ophthalmic acid production is supported by amino acid catabolism under fasting conditions in mice. Biochem Biophys Res Commun 2017; 491:649-655. [DOI: 10.1016/j.bbrc.2017.07.149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 01/18/2023]
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Kang ES, Lee J, Homma T, Kurahashi T, Kobayashi S, Nabeshima A, Yamada S, Seo HG, Miyata S, Sato H, Fujii J. xCT deficiency aggravates acetaminophen-induced hepatotoxicity under inhibition of the transsulfuration pathway. Free Radic Res 2017; 51:80-90. [PMID: 28081640 DOI: 10.1080/10715762.2017.1282157] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Cystine, an oxidized form of cysteine (Cys), is imported into cells via the protein xCT, which is also associated with the export of glutamate as the counter amino acid. In the current study, we attempted to rationalize roles of xCT in the livers of male mice. While xCT was not expressed in the livers of ordinary mice, it was induced under conditions of glutathione depletion, caused by the administration of acetaminophen (AAP). To differentiate the role between xCT and the transsulfuration pathway on the supply of Cys, we employed an inhibitor of the enzyme cystathionine γ-lyase, propargylglycine (PPG). This inhibitor caused a marked aggravation in AAP-induced hepatic damage and the mortality of the xCT-/- mice was increased to a greater extent than that for the xCT+/+ mice. While a PPG pretreatment had no effect on liver condition or Cys levels, the administration of AAP to the PPG-pretreated mice reduced the levels of Cys as well as glutathione to very low levels in both the xCT+/+ and xCT-/- mice. These findings indicate that the transsulfuration pathway plays a major role in replenishing Cys when glutathione levels are low. Moreover, an ascorbic acid insufficiency, induced by Akr1a ablation, further aggravated the AAP-induced liver damage in the case of the xCT deficiency, indicating that glutathione and ascorbic acid function cooperatively in protecting the liver. In conclusion, while the transsulfuration pathway plays a primary role in supplying Cys to the redox system in the liver, xCT is induced in cases of emergencies, by compensating for Cys supply systems.
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Affiliation(s)
- Eun Sil Kang
- a Department of Biochemistry and Molecular Biology , Graduate School of Medical Science, Yamagata University , Yamagata , Japan.,b Department of Animal Biotechnology , Konkuk University , Seoul , Republic of Korea
| | - Jaeyong Lee
- a Department of Biochemistry and Molecular Biology , Graduate School of Medical Science, Yamagata University , Yamagata , Japan
| | - Takujiro Homma
- a Department of Biochemistry and Molecular Biology , Graduate School of Medical Science, Yamagata University , Yamagata , Japan
| | - Toshihiro Kurahashi
- a Department of Biochemistry and Molecular Biology , Graduate School of Medical Science, Yamagata University , Yamagata , Japan
| | - Sho Kobayashi
- a Department of Biochemistry and Molecular Biology , Graduate School of Medical Science, Yamagata University , Yamagata , Japan
| | - Atsunori Nabeshima
- c Department of Pathology and Cell Biology , University of Occupational and Environmental Health , Kitakyushu , Japan
| | - Sohsuke Yamada
- c Department of Pathology and Cell Biology , University of Occupational and Environmental Health , Kitakyushu , Japan
| | - Han Geuk Seo
- b Department of Animal Biotechnology , Konkuk University , Seoul , Republic of Korea
| | - Satoshi Miyata
- d Department of Internal Medicine , Osaka Hospital, Japan Community Healthcare Organization , Osaka , Japan
| | - Hideyo Sato
- e Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology, Faculty of Medicine , Niigata University , Niigata , Japan
| | - Junichi Fujii
- a Department of Biochemistry and Molecular Biology , Graduate School of Medical Science, Yamagata University , Yamagata , Japan
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Ahmad A, Szabo C. Both the H 2S biosynthesis inhibitor aminooxyacetic acid and the mitochondrially targeted H 2S donor AP39 exert protective effects in a mouse model of burn injury. Pharmacol Res 2016; 113:348-355. [PMID: 27639598 DOI: 10.1016/j.phrs.2016.09.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/31/2016] [Accepted: 09/14/2016] [Indexed: 12/19/2022]
Abstract
Hydrogen sulfide (H2S) exerts beneficial as well as deleterious effects in various models of critical illness. Here we tested the effect of two different pharmacological interventions: (a) inhibition of H2S biosynthesis using the cystathionine-beta-synthase (CBS)/cystathionine-gamma-lyase (CSE) inhibitor aminooxyacetic acid (AOAA) and the mitochondrially targeted H2S donor [10-oxo-10-[4-(3-thioxo-3H-1,2-dithiol-5-yl)phenoxy]decyl]triphenyl-phosphonium (AP39). A 30% body surface area burn injury was induced in anesthetized mice; animals were treated with vehicle, AOAA (10mg/kg i.p. once or once a day for 6days), or AP39 (0.3mg/kg/day once or once a day for 6days). In two separate groups, animals were sacrificed, at 24h post-burn or on Day 7 post-burn, blood and lungs were collected and the following parameters were evaluated: myeloperoxidase (MPO) and malondialdehyde (MDA) in lung homogenates, plasma cytokines (Luminex analysis) and circulating indicators of organ dysfunction (Vetscan analysis). Lung MPO levels (an index of neutrophil infiltration) and MDA levels (an index of oxidative stress) were significantly increased in response to burn injury both at 24h and at 7days; both AOAA and AP39 attenuated these increases. From a panel of inflammatory cytokines (TNFα, IL-1β, IL-6, IL-10, MCP-1, MIP-2, VEGF and IFNγ) in the plasma, IL-6 and IL-10 levels were markedly elevated at 24h and VEGF was slightly elevated. IL-6 remained highly elevated at 7days post-burn while IL-10 levels decreased, but remained slightly elevated over baseline 7days post-burn. The changes in cytokine levels were attenuated both by AP39 and AOAA at both time points studied. The burn-induced increases in the organ injury markers ALP and ALT, amylase and creatinine were reduced by both AOAA and AP39. We conclude that both H2S biosynthesis inhibition (using AOAA) and H2S donation (using AP39) suppresses inflammatory mediator production and reduces multi-organ injury in a murine model of burn injury, both at an early time point (when systemic H2S levels are elevated) and at a later time point (at which time systemic H2S levels have returned to baseline). These findings point to the complex pathogenetic role of H2S in burns.
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Affiliation(s)
- Akbar Ahmad
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA; Shriners Hospitals for Children, Galveston, TX, USA
| | - Csaba Szabo
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA; Shriners Hospitals for Children, Galveston, TX, USA.
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Druzhyna N, Szczesny B, Olah G, Módis K, Asimakopoulou A, Pavlidou A, Szoleczky P, Gerö D, Yanagi K, Törö G, López-García I, Myrianthopoulos V, Mikros E, Zatarain JR, Chao C, Papapetropoulos A, Hellmich MR, Szabo C. Screening of a composite library of clinically used drugs and well-characterized pharmacological compounds for cystathionine β-synthase inhibition identifies benserazide as a drug potentially suitable for repurposing for the experimental therapy of colon cancer. Pharmacol Res 2016; 113:18-37. [PMID: 27521834 PMCID: PMC5107130 DOI: 10.1016/j.phrs.2016.08.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 01/23/2023]
Abstract
Cystathionine-β-synthase (CBS) has been recently identified as a drug target for several forms of cancer. Currently no potent and selective CBS inhibitors are available. Using a composite collection of 8871 clinically used drugs and well-annotated pharmacological compounds (including the LOPAC library, the FDA Approved Drug Library, the NIH Clinical Collection, the New Prestwick Chemical Library, the US Drug Collection, the International Drug Collection, the ‘Killer Plates’ collection and a small custom collection of PLP-dependent enzyme inhibitors), we conducted an in vitro screen in order to identify inhibitors for CBS using a primary 7-azido-4-methylcoumarin (AzMc) screen to detect CBS-derived hydrogen sulfide (H2S) production. Initial hits were subjected to counterscreens using the methylene blue assay (a secondary assay to measure H2S production) and were assessed for their ability to quench the H2S signal produced by the H2S donor compound GYY4137. Four compounds, hexachlorophene, tannic acid, aurintricarboxylic acid and benserazide showed concentration-dependent CBS inhibitory actions without scavenging H2S released from GYY4137, identifying them as direct CBS inhibitors. Hexachlorophene (IC50: ∼60 μM), tannic acid (IC50: ∼40 μM) and benserazide (IC50: ∼30 μM) were less potent CBS inhibitors than the two reference compounds AOAA (IC50: ∼3 μM) and NSC67078 (IC50: ∼1 μM), while aurintricarboxylic acid (IC50: ∼3 μM) was equipotent with AOAA. The second reference compound NSC67078 not only inhibited the CBS-induced AzMC fluorescence signal (IC50: ∼1 μM), but also inhibited with the GYY4137-induced AzMC fluorescence signal with (IC50 of ∼6 μM) indicative of scavenging/non-specific effects. Hexachlorophene (IC50: ∼6 μM), tannic acid (IC50: ∼20 μM), benserazide (IC50: ∼20 μM), and NSC67078 (IC50: ∼0.3 μM) inhibited HCT116 colon cancer cells proliferation with greater potency than AOAA (IC50: ∼300 μM). In contrast, although a CBS inhibitor in the cell-free assay, aurintricarboxylic acid failed to inhibit HCT116 proliferation at lower concentrations, and stimulated cell proliferation at 300 μM. Copper-containing compounds present in the libraries, were also found to be potent inhibitors of recombinant CBS; however this activity was due to the CBS inhibitory effect of copper ions themselves. However, copper ions, up to 300 μM, did not inhibit HCT116 cell proliferation. Benserazide was only a weak inhibitor of the activity of the other H2S-generating enzymes CSE and 3-MST activity (16% and 35% inhibition at 100 μM, respectively) in vitro. Benserazide suppressed HCT116 mitochondrial function and inhibited proliferation of the high CBS-expressing colon cancer cell line HT29, but not the low CBS-expressing line, LoVo. The major benserazide metabolite 2,3,4-trihydroxybenzylhydrazine also inhibited CBS activity and suppressed HCT116 cell proliferation in vitro. In an in vivo study of nude mice bearing human colon cancer cell xenografts, benserazide (50 mg/kg/day s.q.) prevented tumor growth. In silico docking simulations showed that benserazide binds in the active site of the enzyme and reacts with the PLP cofactor by forming reversible but kinetically stable Schiff base-like adducts with the formyl moiety of pyridoxal. We conclude that benserazide inhibits CBS activity and suppresses colon cancer cell proliferation and bioenergetics in vitro, and tumor growth in vivo. Further pharmacokinetic, pharmacodynamic and preclinical animal studies are necessary to evaluate the potential of repurposing benserazide for the treatment of colorectal cancers.
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Affiliation(s)
- Nadiya Druzhyna
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Bartosz Szczesny
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Gabor Olah
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Katalin Módis
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA; Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA
| | - Antonia Asimakopoulou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Greece; Center of Clinical, Experimental Surgery & Translational Research, Biomedical Research Foundation of the Academy of Athens, Greece
| | - Athanasia Pavlidou
- National and Kapodistrian University of Athens, School of Pharmacy, Athens, Greece
| | - Petra Szoleczky
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Domokos Gerö
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Kazunori Yanagi
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Gabor Törö
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Isabel López-García
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA
| | | | - Emmanuel Mikros
- National and Kapodistrian University of Athens, School of Pharmacy, Athens, Greece
| | - John R Zatarain
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA
| | - Celia Chao
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA
| | - Andreas Papapetropoulos
- Center of Clinical, Experimental Surgery & Translational Research, Biomedical Research Foundation of the Academy of Athens, Greece; National and Kapodistrian University of Athens, School of Pharmacy, Athens, Greece
| | - Mark R Hellmich
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA; CBS Therapeutics Inc., Galveston, TX, USA
| | - Csaba Szabo
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA; CBS Therapeutics Inc., Galveston, TX, USA.
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Mazzalupo S, Isoe J, Belloni V, Scaraffia PY. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase. FASEB J 2016; 30:111-20. [PMID: 26310269 PMCID: PMC4684537 DOI: 10.1096/fj.15-277087] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/13/2015] [Indexed: 01/01/2023]
Abstract
To better understand the mechanisms responsible for the success of female mosquitoes in their disposal of excess nitrogen, we investigated the role of alanine aminotransferase (ALAT) in blood-fed Aedes aegypti. Transcript and protein levels from the 2 ALAT genes were analyzed in sucrose- and blood-fed A. aegypti tissues. ALAT1 and ALAT2 exhibit distinct expression patterns in tissues during the first gonotrophic cycle. Injection of female mosquitoes with either double-stranded RNA (dsRNA)-ALAT1 or dsRNA ALAT2 significantly decreased mRNA and protein levels of ALAT1 or ALAT2 in fat body, thorax, and Malpighian tubules compared with dsRNA firefly luciferase-injected control mosquitoes. The silencing of either A. aegypti ALAT1 or ALAT2 caused unexpected phenotypes such as a delay in blood digestion, a massive accumulation of uric acid in the midgut posterior region, and a significant decrease of nitrogen waste excretion during the first 48 h after blood feeding. Concurrently, the expression of genes encoding xanthine dehydrogenase and ammonia transporter (Rhesus 50 glycoprotein) were significantly increased in tissues of both ALAT1- and ALAT2-deficient females. Moreover, perturbation of ALAT1 and ALAT2 in the female mosquitoes delayed oviposition and reduced egg production. These novel findings underscore the efficient mechanisms that blood-fed mosquitoes use to avoid ammonia toxicity and free radical damage.-Mazzalupo, S., Isoe, J., Belloni, V., Scaraffia, P. Y. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.
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Affiliation(s)
- Stacy Mazzalupo
- *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | - Jun Isoe
- *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | - Virginia Belloni
- *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | - Patricia Y Scaraffia
- *Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA; and Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
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Syhr KM, Boosen M, Hohmann SW, Longen S, Köhler Y, Pfeilschifter J, Beck KF, Geisslinger G, Schmidtko A, Kallenborn-Gerhardt W. The H 2 S-producing enzyme CSE is dispensable for the processing of inflammatory and neuropathic pain. Brain Res 2015; 1624:380-389. [DOI: 10.1016/j.brainres.2015.07.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/28/2015] [Accepted: 07/31/2015] [Indexed: 10/23/2022]
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Abstract
Hydrogen sulfide (H₂S) has emerged as an important signaling molecule with beneficial effects on various cellular processes affecting, for example, cardiovascular and neurological functions. The physiological importance of H₂S is motivating efforts to develop strategies for modulating its levels. However, advancement in the field of H₂S-based therapeutics is hampered by fundamental gaps in our knowledge of how H₂S is regulated, its mechanism of action, and its molecular targets. This review provides an overview of sulfur metabolism; describes recent progress that has shed light on the mechanism of H₂S as a signaling molecule; and examines nutritional regulation of sulfur metabolism, which pertains to health and disease.
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Affiliation(s)
- Omer Kabil
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600;
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Rojas Murcia N, Lee X, Waridel P, Maspoli A, Imker HJ, Chai T, Walsh CT, Reimmann C. The Pseudomonas aeruginosa antimetabolite L -2-amino-4-methoxy-trans-3-butenoic acid (AMB) is made from glutamate and two alanine residues via a thiotemplate-linked tripeptide precursor. Front Microbiol 2015; 6:170. [PMID: 25814981 PMCID: PMC4357302 DOI: 10.3389/fmicb.2015.00170] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/13/2015] [Indexed: 11/25/2022] Open
Abstract
The Pseudomonas aeruginosa toxin L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is a non-proteinogenic amino acid which is toxic for prokaryotes and eukaryotes. Production of AMB requires a five-gene cluster encoding a putative LysE-type transporter (AmbA), two non-ribosomal peptide synthetases (AmbB and AmbE), and two iron(II)/α-ketoglutarate-dependent oxygenases (AmbC and AmbD). Bioinformatics analysis predicts one thiolation (T) domain for AmbB and two T domains (T1 and T2) for AmbE, suggesting that AMB is generated by a processing step from a precursor tripeptide assembled on a thiotemplate. Using a combination of ATP-PPi exchange assays, aminoacylation assays, and mass spectrometry-based analysis of enzyme-bound substrates and pathway intermediates, the AmbB substrate was identified to be L-alanine (L-Ala), while the T1 and T2 domains of AmbE were loaded with L-glutamate (L-Glu) and L-Ala, respectively. Loading of L-Ala at T2 of AmbE occurred only in the presence of AmbB, indicative of a trans loading mechanism. In vitro assays performed with AmbB and AmbE revealed the dipeptide L-Glu-L-Ala at T1 and the tripeptide L-Ala-L-Glu-L-Ala attached at T2. When AmbC and AmbD were included in the assay, these peptides were no longer detected. Instead, an L-Ala-AMB-L-Ala tripeptide was found at T2. These data are in agreement with a biosynthetic model in which L-Glu is converted into AMB by the action of AmbC, AmbD, and tailoring domains of AmbE. The importance of the flanking L-Ala residues in the precursor tripeptide is discussed.
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Affiliation(s)
- Nelson Rojas Murcia
- Department of Fundamental Microbiology, University of Lausanne, Lausanne Switzerland
| | - Xiaoyun Lee
- Department of Fundamental Microbiology, University of Lausanne, Lausanne Switzerland
| | - Patrice Waridel
- Protein Analysis Facility, University of Lausanne, Lausanne Switzerland
| | - Alessandro Maspoli
- Department of Fundamental Microbiology, University of Lausanne, Lausanne Switzerland
| | - Heidi J Imker
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA USA
| | - Tiancong Chai
- Department of Fundamental Microbiology, University of Lausanne, Lausanne Switzerland
| | - Christopher T Walsh
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA USA
| | - Cornelia Reimmann
- Department of Fundamental Microbiology, University of Lausanne, Lausanne Switzerland
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Wallace JL, Blackler RW, Chan MV, Da Silva GJ, Elsheikh W, Flannigan KL, Gamaniek I, Manko A, Wang L, Motta JP, Buret AG. Anti-inflammatory and cytoprotective actions of hydrogen sulfide: translation to therapeutics. Antioxid Redox Signal 2015; 22:398-410. [PMID: 24635322 DOI: 10.1089/ars.2014.5901] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
SIGNIFICANCE There is a rapidly expanding body of evidence for important roles of hydrogen sulfide in protecting against tissue injury, reducing inflammation, and promoting repair. There is also growing evidence that H2S can be successfully exploited in drug development. RECENT ADVANCES H2S synthesis and degradation are regulated in circumstances of inflammation and injury so as to promote repair and re-establish homeostasis. Novel H2S-releasing drugs exhibit enhanced anti-inflammatory and pro-restorative effects, while having reduced adverse effects in many tissues. CRITICAL ISSUES H2S is a pleiotropic mediator, having effects on many elements in the inflammatory cascade and promoting the resolution of inflammation and injury. It also contributes significantly to mucosal defence in the gastrointestinal tract, and in host defence against infection. There is strong evidence that novel, H2S-based therapeutics are safe and effective in animal models, and several are progressing through human trials. FUTURE DIRECTIONS A better understanding of the physiological and pathophysiological roles of H2S continues to be restrained by the lack of simple, reliable methods for measurement of H2S synthesis, and the paucity of highly selective inhibitors of enzymes that participate in endogenous H2S synthesis. On the other hand, H2S donors show promise as therapeutics for several important indications.
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Affiliation(s)
- John L Wallace
- 1 Department of Physiology & Pharmacology, University of Calgary , Calgary, Canada
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Inhibition study of alanine aminotransferase enzyme using sequential online capillary electrophoresis analysis. Anal Biochem 2014; 467:28-30. [DOI: 10.1016/j.ab.2014.08.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/26/2014] [Accepted: 08/29/2014] [Indexed: 02/02/2023]
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Asimakopoulou A, Panopoulos P, Chasapis CT, Coletta C, Zhou Z, Cirino G, Giannis A, Szabo C, Spyroulias GA, Papapetropoulos A. Selectivity of commonly used pharmacological inhibitors for cystathionine β synthase (CBS) and cystathionine γ lyase (CSE). Br J Pharmacol 2014; 169:922-32. [PMID: 23488457 PMCID: PMC3687671 DOI: 10.1111/bph.12171] [Citation(s) in RCA: 311] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 02/01/2013] [Accepted: 02/17/2013] [Indexed: 12/01/2022] Open
Abstract
Background and Purpose Hydrogen sulfide (H2S) is a signalling molecule that belongs to the gasotransmitter family. Two major sources for endogenous enzymatic production of H2S are cystathionine β synthase (CBS) and cystathionine γ lyase (CSE). In the present study, we examined the selectivity of commonly used pharmacological inhibitors of H2S biosynthesis towards CSE and CBS. Experimental Approach To address this question, human CSE or CBS enzymes were expressed and purified from Escherichia coli as fusion proteins with GSH-S-transferase. After purification, the activity of the recombinant enzymes was tested using the methylene blue method. Key Results β-cyanoalanine (BCA) was more potent in inhibiting CSE than propargylglycine (PAG) (IC50 14 ± 0.2 μM vs. 40 ± 8 μM respectively). Similar to PAG, L-aminoethoxyvinylglycine (AVG) only inhibited CSE, but did so at much lower concentrations. On the other hand, aminooxyacetic acid (AOAA), a frequently used CBS inhibitor, was more potent in inhibiting CSE compared with BCA and PAG (IC50 1.1 ± 0.1 μM); the IC50 for AOAA for inhibiting CBS was 8.5 ± 0.7 μM. In line with our biochemical observations, relaxation to L-cysteine was blocked by AOAA in aortic rings that lacked CBS expression. Trifluoroalanine and hydroxylamine, two compounds that have also been used to block H2S biosynthesis, blocked the activity of CBS and CSE. Trifluoroalanine had a fourfold lower IC50 for CBS versus CSE, while hydroxylamine was 60-fold more selective against CSE. Conclusions and Implications In conclusion, although PAG, AVG and BCA exhibit selectivity in inhibiting CSE versus CBS, no selective pharmacological CBS inhibitor is currently available.
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Affiliation(s)
- Antonia Asimakopoulou
- Department of Pharmacy, Laboratory of Molecular Pharmacology, University of Patras, Patras, Greece
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Belloni V, Scaraffia PY. Exposure to L-cycloserine incurs survival costs and behavioral alterations in Aedes aegypti females. Parasit Vectors 2014; 7:373. [PMID: 25129074 PMCID: PMC4261769 DOI: 10.1186/1756-3305-7-373] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 07/17/2014] [Indexed: 11/25/2022] Open
Abstract
Background It was previously demonstrated that alanine aminotransferase (ALAT, EC 2.6.1.2) participates in maintaining the alanine-proline cycle between flight muscles and fat body during Aedes aegypti flight. ALAT is also actively involved in the metabolism of ammonia in A. aegypti. Here, we investigated the survival and behavioral costs of ALAT inhibition in A. aegypti females to better understand the role of ALAT in blood-fed mosquitoes. Methods We analyzed how A. aegypti female mosquitoes respond to blood meals supplemented with 0, 2.5, 5 and 10 mM L-cycloserine, a well-known inhibitor of ALAT in animals. Mosquitoes were also exposed to blood meals supplemented with L-cycloserine and different concentrations of glucose (0, 10 and 100 mM). Additionally, the effects of ALAT inhibitor and glucose in mosquitoes starved for 24 or 48 h were investigated. Survival and behavioral phenotypes were analyzed during a time course (1, 2, 4, 6, 12, 24, 48 and 72 h after feeding). Results L-cycloserine at 10 mM resulted in high mortality relative to control, with an acute effect during the first 6 h after treatment. A significant decrease in the number of active mosquitoes coinciding with an increase in futile wing fanning during the first 24 h was observed at all inhibitor concentrations. A high occurrence of knockdown phenotype was also recorded at this time for both 5 and 10 mM L-cycloserine. The supplementation of glucose in the blood meal amplified the effects of the ALAT inhibitor. In particular, we observed a higher mortality rate concomitant with an increase in the knockdown phenotype. Starvation prior to blood feeding also increased the effects of L-cycloserine with a rapid increase in mortality. Conclusions Our results provide evidence that exposure of high doses of L-cycloserine during A. aegypti blood feeding affects mosquito survival and motor activity, suggesting an interference with carbohydrate and ammonia metabolism in a time-dependent manner. Electronic supplementary material The online version of this article (doi:10.1186/1756-3305-7-373) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Patricia Y Scaraffia
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, 1430 Tulane Ave,, SL-17, New Orleans, LA 70112, USA.
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Flannigan KL, Ferraz JGP, Wang R, Wallace JL. Enhanced synthesis and diminished degradation of hydrogen sulfide in experimental colitis: a site-specific, pro-resolution mechanism. PLoS One 2013; 8:e71962. [PMID: 23940796 PMCID: PMC3733965 DOI: 10.1371/journal.pone.0071962] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 07/06/2013] [Indexed: 11/18/2022] Open
Abstract
Hydrogen sulfide (H2S) is produced throughout the gastrointestinal tract, and it contributes to maintenance of mucosal integrity, resolution of inflammation, and repair of damaged tissue. H2S synthesis is elevated in inflamed and damaged colonic tissue, but the enzymatic sources of that synthesis are not completely understood. In the present study, the contributions of three enzymatic pathways to colonic H2S synthesis were determined, with tissues taken from healthy rats and rats with colitis. The ability of the colonic tissue to inactivate H2S was also determined. Colonic tissue from rats with hapten-induced colitis produced significantly more H2S than tissue from healthy controls. The largest source of the H2S synthesis was the pathway involving cysteine amino transferase and 3-mercaptopyruvate sulfurtransferase (an α-ketoglutarate-dependent pathway). Elevated H2S synthesis occurred specifically at sites of mucosal ulceration, and was not related to the extent of granulocyte infiltration into the tissue. Inactivation of H2S by colonic tissue occurred rapidly, and was significantly reduced at sites of mucosal ulceration. This correlated with a marked decrease in the expression of sulfide quinone reductase in these regions. Together, the increased production and decreased inactivation of H2S at sites of mucosal ulceration would result in higher H2S levels at these sites, which promotes of resolution of inflammation and repair of damaged tissue.
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Affiliation(s)
- Kyle L. Flannigan
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Jose G. P. Ferraz
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
| | - Rui Wang
- Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
| | - John L. Wallace
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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Duff SM, Rydel TJ, McClerren AL, Zhang W, Li JY, Sturman EJ, Halls C, Chen S, Zeng J, Peng J, Kretzler CN, Evdokimov A. The Enzymology of alanine aminotransferase (AlaAT) isoforms from Hordeum vulgare and other organisms, and the HvAlaAT crystal structure. Arch Biochem Biophys 2012; 528:90-101. [DOI: 10.1016/j.abb.2012.06.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/19/2012] [Accepted: 06/20/2012] [Indexed: 11/15/2022]
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Storm J, Perner J, Aparicio I, Patzewitz EM, Olszewski K, Llinas M, Engel PC, Müller S. Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development. Malar J 2011; 10:193. [PMID: 21756354 PMCID: PMC3163627 DOI: 10.1186/1475-2875-10-193] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 07/14/2011] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium falciparum contains three genes encoding potential glutamate dehydrogenases. The protein encoded by gdha has previously been biochemically and structurally characterized. It was suggested that it is important for the supply of reducing equivalents during intra-erythrocytic development of Plasmodium and, therefore, a suitable drug target. Methods The gene encoding the NADP(H)-dependent GDHa has been disrupted by reverse genetics in P. falciparum and the effect on the antioxidant and metabolic capacities of the resulting mutant parasites was investigated. Results No growth defect under low and elevated oxygen tension, no up- or down-regulation of a number of antioxidant and NADP(H)-generating proteins or mRNAs and no increased levels of GSH were detected in the D10Δgdha parasite lines. Further, the fate of the carbon skeleton of [13C] labelled glutamine was assessed by metabolomic studies, revealing no differences in the labelling of α-ketoglutarate and other TCA pathway intermediates between wild type and mutant parasites. Conclusions First, the data support the conclusion that D10Δgdha parasites are not experiencing enhanced oxidative stress and that GDHa function may not be the provision of NADP(H) for reductive reactions. Second, the results imply that the cytosolic, NADP(H)-dependent GDHa protein is not involved in the oxidative deamination of glutamate but that the protein may play a role in ammonia assimilation as has been described for other NADP(H)-dependent GDH from plants and fungi. The lack of an obvious phenotype in the absence of GDHa may point to a regulatory role of the protein providing glutamate (as nitrogen storage molecule) in situations where the parasites experience a limiting supply of carbon sources and, therefore, under in vitro conditions the enzyme is unlikely to be of significant importance. The data imply that the protein is not a suitable target for future drug development against intra-erythrocytic parasite development.
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Affiliation(s)
- Janet Storm
- Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, Sir Graeme Davies Building, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
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Beuster G, Zarse K, Kaleta C, Thierbach R, Kiehntopf M, Steinberg P, Schuster S, Ristow M. Inhibition of alanine aminotransferase in silico and in vivo promotes mitochondrial metabolism to impair malignant growth. J Biol Chem 2011; 286:22323-30. [PMID: 21540181 PMCID: PMC3121379 DOI: 10.1074/jbc.m110.205229] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cancer cells commonly exhibit increased nonoxidative d-glucose metabolism whereas induction of mitochondrial metabolism may impair malignant growth. We have first used an in silico method called elementary mode analysis to identify inhibition of ALAT (l-alanine aminotransferase) as a putative target to promote mitochondrial metabolism. We then experimentally show that two competitive inhibitors of ALAT, l-cycloserine and β-chloro-l-alanine, inhibit l-alanine production and impair d-glucose uptake of LLC1 Lewis lung carcinoma cells. The latter inhibition is linked to an initial energy deficit, as quantified by decreased ATP content, which is then followed by an activation of AMP-activated protein kinase and subsequently increased respiration rates and mitochondrial production of reactive oxygen species, culminating in ATP replenishment in ALAT-inhibited LLC1 cells. Moreover, we observe altered phosphorylation of p38 MAPK (mitogen-activated protein kinase 14), ERK (extracellular signal-regulated kinase 1/2), and Rb1 (retinoblastoma 1) proteins, as well as decreased expression of Cdc25a (cell decision cycle 25 homolog A) and Cdk4 (cyclin-dependent kinase 4). Importantly, these sequelae of ALAT inhibition culminate in similarly reduced anchorage-dependent and anchorage-independent growth rates of LLC1 cells, together suggesting that inhibition of ALAT efficiently impairs cancer growth by counteracting the Warburg effect due to compensatory activation of mitochondrial metabolism.
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Affiliation(s)
- Gregor Beuster
- Department of Human Nutrition, Institute of Nutrition, University of Jena, Jena D-07743, Germany
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Identification of the biosynthetic gene cluster for the Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid. J Bacteriol 2010; 192:4251-5. [PMID: 20543073 DOI: 10.1128/jb.00492-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is a potent antibiotic and toxin produced by Pseudomonas aeruginosa. Using a novel biochemical assay combined with site-directed mutagenesis in strain PAO1, we have identified a five-gene cluster specifying AMB biosynthesis, probably involving a thiotemplate mechanism. Overexpression of this cluster in strain PA7, a natural AMB-negative isolate, led to AMB overproduction.
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Miyazaki M, Rosenblum JS, Kasahara Y, Nakagawa I, Patricelli MP. Determination of enzymatic source of alanine aminotransferase activity in serum from dogs with liver injury. J Pharmacol Toxicol Methods 2009; 60:307-15. [PMID: 19748590 DOI: 10.1016/j.vascn.2009.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 08/31/2009] [Accepted: 09/01/2009] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Increase of serum alanine aminotransferase (ALT) activity is widely used as a surrogate marker for tissue damage. Two ALT isoforms, ALT1 and ALT2, have been cloned recently in mammals. The study investigated the source of elevated ALT activity in serum of dogs treated with a hepatotoxic compound. METHODS ALT activity was measured by enzyme assay. Immunoblot analysis was performed using generated specific peptide antibodies against dog ALTs. LC-MS/MS-based proteomics analysis was conducted to independently identify dog ALT peptides. Serum samples immunodepleted of major serum components by Seppro IgY-D11 microbead spin column were evaluated by the immunoblot analysis, and compared with those of the ALT activity. RESULTS Involvement of ALT enzyme(s) is consistent with the following observations: 1) all the substrates (L-alanine and alpha-ketoglutarate) were required for serum ALT activity as purified porcine ALT1 needed for activity, 2) serum ALT activity was inhibited by L-cycloserine, a known ALT inhibitor, and 3) apparent Km value for the ALT reaction catalyzed by the serum, liver, and skeletal muscle was roughly similar. Immunoblot analysis showed that ALT1 was detected in liver and both ALTs were detected in the skeletal muscle. The relative expression level of ALTs was -: liver ALT1>skeletal muscle ALT1>skeletal muscle ALT2. LC-MS/MS-based proteomics analysis gave similar results. Immunoblot analysis of the depleted serum samples revealed the presence of ALT1 in compound-treated dogs. Intensity of the ALT1 band detected in the sera correlated well with the ALT activity measured by the enzyme assay. DISCUSSION Based on these findings, we conclude that the elevation of serum ALT activity in dogs with liver injury is attributed to elevation of ALT1 protein level in serum. The methodology to directly detect ALT proteins in serum could be a tool to facilitate our understanding of biological and toxicological significance of the ALT isoenzymes.
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Affiliation(s)
- Masafumi Miyazaki
- ActivX Biosciences Inc., 11025 North Torrey Pines Road, La Jolla, California 92037, USA.
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Jackson ER, Kilroy C, Joslin DL, Schomaker SJ, Pruimboom-Brees I, Amacher DE. The early effects of short-term dexamethasone administration on hepatic and serum alanine aminotransferase in the rat. Drug Chem Toxicol 2009; 31:427-45. [PMID: 18850354 DOI: 10.1080/01480540802390247] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Dexamethasone (DEXA) administration has been associated with serum alanine aminotransferase (ALT) elevations that may result from enhanced ALT expression. The aim of our current study was to compare liver vs. serum ALT activity and to examine the onset of any hepatocellular changes. Groups of 4 male Sprague-Dawley rats were administered a single dose of DEXA or corn oil at 12, 16, and 24 h prior to euthanasia or once-daily for 2, 3, or 4 days. All (nonfasted) rats were necropsied together on Day 5. While DEXA incrementally increased liver ALT activity in the 1-, 2-, 3-, and 4-day treatment groups (maximal, 3.7-fold), liver aspartate aminotransferase (AST) never exceeded 1.4-fold over control. Significant hepatic glycogen elevations were detected after DEXA treatment, which correlated with microscopic observations. Serum ALT, AST, sorbitol dehydrogenase, and glutamate dehydrogenase (GLDH) increased after 2, 3, and 4 days of DEXA dosing (1.3-10.3-fold). DEXA-related necropsy findings included pale livers consistent with glycogen deposition. The relative percent liver to body weight was elevated in all DEXA-treated rats. Hepatocellular necrosis was observed in 1/4 rats at 12 h, 2/4 rats at 2 days, 4/4 rats at 3 days, and 3/4 rats at 4 days. DEXA treatment <2 days failed to produce consistent evidence of hepatic injury, as detected by serum biomarkers and pathology assessment. However, early DEXA treatment did correlate with apparent ALT induction. Ultimately, this may explain some early asymptomatic serum ALT elevations seen clinically.
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Affiliation(s)
- Elisa R Jackson
- Portfolio and Project Management-Project Planning, Pfizer Inc. Pfizer Global Research and Development, New London, Connecticut 06320, USA.
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Yang L, Kombu RS, Kasumov T, Zhu SH, Cendrowski AV, David F, Anderson VE, Kelleher JK, Brunengraber H. Metabolomic and mass isotopomer analysis of liver gluconeogenesis and citric acid cycle. I. Interrelation between gluconeogenesis and cataplerosis; formation of methoxamates from aminooxyacetate and ketoacids. J Biol Chem 2008; 283:21978-87. [PMID: 18544527 PMCID: PMC2494924 DOI: 10.1074/jbc.m803454200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 06/09/2008] [Indexed: 11/06/2022] Open
Abstract
We conducted a study coupling metabolomics and mass isotopomer analysis of liver gluconeogenesis and citric acid cycle. Rat livers were perfused with lactate or pyruvate +/- aminooxyacetate or mercaptopicolinate in the presence of 40% enriched NaH(13)CO(3). Other livers were perfused with dimethyl [1,4-(13)C(2)]succinate +/- mercaptopicolinate. In this first of two companion articles, we show that a substantial fraction of gluconeogenic carbon leaves the liver as citric acid cycle intermediates, mostly alpha-ketoglutarate. The efflux of gluconeogenic carbon ranges from 10 to 200% of the rate of liver gluconeogenesis. This cataplerotic efflux of gluconeogenic carbon may contribute to renal gluconeogenesis in vivo. Multiple crossover analyses of concentrations of gluconeogenic intermediates and redox measurements expand previous reports on the regulation of gluconeogenesis and the effects of inhibitors. We also demonstrate the formation of adducts from the condensation, in the liver, of (i) aminooxyacetate with pyruvate, alpha-ketoglutarate, and oxaloacetate and (ii) mercaptopicolinate and pyruvate. These adducts may exert metabolic effects unrelated to their effect on gluconeogenesis.
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Affiliation(s)
- Lili Yang
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Yang L, Kasumov T, Kombu RS, Zhu SH, Cendrowski AV, David F, Anderson VE, Kelleher JK, Brunengraber H. Metabolomic and mass isotopomer analysis of liver gluconeogenesis and citric acid cycle: II. Heterogeneity of metabolite labeling pattern. J Biol Chem 2008; 283:21988-96. [PMID: 18544526 DOI: 10.1074/jbc.m803455200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this second of two companion articles, we compare the mass isotopomer distribution of metabolites of liver gluconeogenesis and citric acid cycle labeled from NaH(13)CO(3) or dimethyl [1,4-(13)C(2)]succinate. The mass isotopomer distribution of intermediates reveals the reversibility of the isocitrate dehydrogenase + aconitase reactions, even in the absence of a source of alpha-ketoglutarate. In addition, in many cases, a number of labeling incompatibilities were found as follows: (i) glucose versus triose phosphates and phosphoenolpyruvate; (ii) differences in the labeling ratios C-4/C-3 of glucose versus (glyceraldehyde 3-phosphate)/(dihydroxyacetone phosphate); and (iii) labeling of citric acid cycle intermediates in tissue versus effluent perfusate. Overall, our data show that gluconeogenic and citric acid cycle intermediates cannot be considered as sets of homogeneously labeled pools. This probably results from the zonation of hepatic metabolism and, in some cases, from differences in the labeling pattern of mitochondrial versus extramitochondrial metabolites. Our data have implications for the use of labeling patterns for the calculation of metabolic rates or fractional syntheses in liver, as well as for modeling liver intermediary metabolism.
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Affiliation(s)
- Lili Yang
- Departments of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Berkowitz DB, Charette BD, Karukurichi KR, McFadden JM. α-Vinylic Amino Acids: Occurrence, Asymmetric Synthesis and Biochemical Mechanisms. TETRAHEDRON, ASYMMETRY 2006; 17:869-882. [PMID: 29977107 PMCID: PMC6029878 DOI: 10.1016/j.tetasy.2006.02.026] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
This report presents an overview of the family of naturally occurring 'vinylic' amino acids, namely those that feature a C-C double bond directly attached to the α-carbon, along the side chain. Strategies that have been brought to bear on the stereocontrolled synthesis of these olefinic amino acids are surveyed. The mechanistic diversity by which such 'vinylic triggers' can be actuated in a PLP (pyridoxal phosphate) enzyme active site is then highlighted by discussions of vinylglycine (VG), its substituted congeners, particularly AVG [4E-(2'-aminoethoxy)vinylglycine], and a naturally occurring VG-progenitor, SMM (S-methylmethionine).
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Affiliation(s)
- David B Berkowitz
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304
| | | | | | - Jill M McFadden
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304
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Dawson KD, Baker DJ, Greenhaff PL, Gibala MJ. An acute decrease in TCA cycle intermediates does not affect aerobic energy delivery in contracting rat skeletal muscle. J Physiol 2005; 565:637-43. [PMID: 15802296 PMCID: PMC1464528 DOI: 10.1113/jphysiol.2004.079939] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We tested the hypothesis that an acute decrease in muscle TCA cycle intermediates during contraction would compromise aerobic energy delivery. Male Wistar rats were anaesthetized and the gastrocnemius-plantaris-soleus (GPS) muscle complex from one leg was isolated and perfused with a red cell medium containing either saline (Con) or cycloserine (Cyclo; 0.05 mg g-1), an inhibitor of alanine aminotransferase (AAT). After 1 h of perfusion, the GPS muscle was either snap frozen (Con-Rest, n=11; Cyclo-Rest, n=9) or stimulated to contract for 10 min (1 Hz, 0.3 ms, 2 V) with blood flow fixed at 30 ml min-1 (100 g)-1 and then snap frozen (Con-Stim, n=10; Cyclo-Stim, n=10). Maximal AAT activity was>80% lower (P<0.001) in both Cyclo-treated groups (Rest: 0.61+/-0.02; Stim: 0.63+/-0.01 mmol (kg wet wt)-1 min-1; mean+/-s.e.m.) compared to Con (Rest: 3.56+/-0.16; Stim: 3.92+/-0.29). The sum of five measured TCAI (SigmaTCAI) was reduced by 23% in Cyclo-Rest versus Con-Rest but this was not different (P=0.08). However, after 10 min of contraction, the SigmaTCAI was 25% lower (P=0.006) in Cyclo-Stim compared to Con-Stim (1.88+/-0.15 versus 2.48+/-0.11 mmol (kg dry wt)-1). Despite the acute decrease in TCAI after Cyclo treatment, the contraction-induced changes in markers of non-oxidative energy provision (phosphocreatine, ATP and lactate) and the decline in tension after 10 min of stimulation were similar compared to Con. These data do not support the hypothesis that the total muscle concentration of TCAI is causally linked to the rate of mitochondrial respiration during contraction.
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Affiliation(s)
- Kristen D Dawson
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada L8S 4K1
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Affiliation(s)
- David B. Berkowitz
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304 (USA), Fax: (+1)402-472-9402,
| | - Mohua Bose
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304 (USA), Fax: (+1)402-472-9402,
| | - Sungjo Choi
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304 (USA), Fax: (+1)402-472-9402,
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Berkowitz DB, Bose M, Choi S. In Situ Enzymatic Screening (ISES): A Tool for Catalyst Discovery and Reaction Development. Angew Chem Int Ed Engl 2002. [DOI: 10.1002/1521-3757(20020503)114:9<1673::aid-ange1673>3.0.co;2-k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Berkowitz DB, Chisowa E, McFadden JM. Stereocontrolled Synthesis of Quaternary β,γ-Unsaturated Amino Acids: Chain Extension of D- & L- α-(2-Tributylstannyl)Vinyl Amino Acids. Tetrahedron 2001; 57:6329-6343. [PMID: 29973743 PMCID: PMC6027620 DOI: 10.1016/s0040-4020(01)00499-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A pair of diastereomeric (4S,5S)- and (4S,5R)-4-methoxycarbonyl-5-phenylselenomethyl-2-phenyl oxazolines, derived from L-vinylglycine, serve as precursors to protected, quaternary, L- and D-α-(2-tributylstannyl)vinyl amino acids, respectively, in three steps {(i) alkylative side chain installation, (ii) eliminative ring-opening and (iii) vinyl selenide to vinyl stannane interconversion}. The title compounds may be protodestannylated to the corresponding free, quaternary L- and D-vinyl amino acids. Alternatively, the 2-stannylvinyl α-branch (or the derivative 2-iodovinyl branch) may be exploited to access novel quaternary, L- and D-β,γ-unsaturated amino acids via a range of transition metal-mediated cross coupling reactions.
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Affiliation(s)
- David B Berkowitz
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304
| | - Esmort Chisowa
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304
| | - Jill M McFadden
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304
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Lertratanangkoon K, Scimeca JM, Wei JN. Inhibition of glutathione synthesis with propargylglycine enhances N-acetylmethionine protection and methylation in bromobenzene-treated Syrian hamsters. J Nutr 1999; 129:649-56. [PMID: 10082769 DOI: 10.1093/jn/129.3.649] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The finding that liver necrosis caused by the environmental glutathione (GSH)-depleting chemical, bromobenzene (BB) is associated with marked impairment in O- and S-methylation of BB metabolites in Syrian hamsters raises questions concerning the role of methyl deficiency in BB toxicity. N-Acetylmethionine (NAM) has proven to be an effective antidote against BB toxicity when given after liver GSH has been depleted extensively. The mechanism of protection by NAM may occur via a replacement of methyl donor and/or via an increase of GSH synthesis. If replacement of the methyl donor is an important process, then blocking the resynthesis of GSH in the methyl-repleted hamsters should not decrease NAM protection. This hypothesis was examined in this study. Propargylglycine (PPG), an irreversible inhibitor of cystathionase, was used to inhibit the utilization of NAM for GSH resynthesis. Two groups of hamsters were pretreated with an intraperitoneal (ip) dose of PPG (30 mg/kg) or saline 24 h before BB administration (800 mg/kg, ip). At 5 h after BB treatment, an ip dose of NAM (1200 mg/kg) was given. Light microscopic examinations of liver sections obtained 24 h after BB treatment indicated that NAM provided better protection (P < 0.05) in the PPG + BB + NAM group than in the BB + NAM group. Liver GSH content, however, was lower in the PPG + BB + NAM group than in the BB + NAM group. The Syrian hamster has a limited capability to N-deacetylated NAM. The substitution of NAM with methionine (Met; 450 mg/kg) resulted in a higher level of GSH in the BB + Met group than in the BB + NAM group (P < 0.05). The enhanced protection by PPG in the PPG + BB + NAM group was accompanied by higher (P < 0.05) urinary excretions of specificO- and S-methylated bromothiocatechols than in the BB + NAM group. The results suggest that NAM protection occurs primarily via a replacement of the methyl donor and that methyl deficiency occurring in response to GSH repletion plays a potential role in BB toxicity.
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Affiliation(s)
- K Lertratanangkoon
- Departments of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555-1031, USA
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Rigoulet M, Devin A, Espié P, Guérin B, Fontaine E, Piquet MA, Nogueira V, Leverve X. Flux-force relationships in intact cells: a helpful tool for understanding the mechanism of oxidative phosphorylation alterations? BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1365:117-24. [PMID: 9693730 DOI: 10.1016/s0005-2728(98)00051-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
On isolated mitochondria, numerous studies of the relationships between fluxes and their associated forces have led to the description of some properties of the oxidative phosphorylation pathway. However whether such an approach can be applied to understanding the actual situation in intact living cells needs further consideration. In this study on isolated hepatocytes, we describe the dependence of the respiratory rate on the three thermodynamic forces linked to oxidative phosphorylation (i.e. the redox span over the respiratory chain, the electrical potential difference across the inner mitochondrial membrane and the free energy of ATP synthesis reaction). Even if this description is phenomenological and some objections may be raised regarding the relevance of such a bulk-phase force estimation, we present some results showing that the study of flux-force relationships in intact cells may be a helpful approach for understanding the mechanisms by which oxidative phosphorylation activity is changed.
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Affiliation(s)
- M Rigoulet
- Institut de Biochimie et Génétique Cellulaires du C.N.R.S., Université de Bordeaux, Bordeaux, France.
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Espié P, Devin A, Guérin B, Rigoulet M. Energetics of isolated hepatocyte swelling induced by sodium co-transported amino acids. J Bioenerg Biomembr 1997; 29:591-601. [PMID: 9559860 DOI: 10.1023/a:1022487119390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was designed to investigate the energetics of isolated rat hepatocyte swelling due to sodium-cotransported amino acid accumulation in a medium containing either glucose or octanoate as basal substrate. We show that the size of the increase in cytosolic volume is directly correlated with the total amino acid accumulation, which depends on the difference of electrical potential across the plasma membrane. Such a change in cell volume, with either glucose or octanoate, does not modify the mitochondrial volume. Addition of sodium-cotransported amino acids for which the metabolism was avoided showed that the rise in cell volume, per se, did not change the respiratory rate, deltap, or phosphate potential in either mitochondrial or cytosolic compartments. Conversely, the large increase in oxidative phosphorylation flux was due to the metabolism of amino acids as a consequence of a rise in electron supply for the respiratory chain rather than an increase in cellular ATP demand, as indicated by the increase in cytosolic phosphate potential. Moreover, although we confirm that octanoate addition largely increases the respiratory rate by a process different from uncoupling, we observed that the same overall thermodynamic driving force through the respiratory chain and the same mitochondrial or cytosolic phosphate potential were maintained for much higher oxygen consumption when octanoate was present. We propose that these octanoate effects are due to a decrease in the actual protons/2 electrons stoichiometry as a consequence of a shift in electron supply toward a two-coupling site instead of a three-coupling site. The change in the FADH2/NADH formation flux ratio in either fatty acid or carbohydrate oxidation explains such results.
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Affiliation(s)
- P Espié
- Institut de Biochimie et Génétique Cellulaires du CNRS, Bordeaux, France
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Triguero A, Barber T, García C, Puertes IR, Sastre J, Viña JR. Liver intracellular L-cysteine concentration is maintained after inhibition of the trans-sulfuration pathway by propargylglycine in rats. Br J Nutr 1997; 78:823-31. [PMID: 9389904 DOI: 10.1079/bjn19970198] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To study the fate of L-cysteine and amino acid homeostasis in liver after the inhibition of the trans-sulfuration pathway, rats were treated with propargylglycine (PPG). At 4 h after the administration of PPG, liver cystathionase (EC 4.4.1.1) activity was undetectable, L-cystathionine levels were significantly higher, L-cysteine was unchanged and GSH concentration was significantly lower than values found in livers from control rats injected intraperitoneally with 0.15 M-NaCl. The hepatic levels of amino acids that are intermediates of the urea cycle, L-ornithine, L-citrulline and L-arginine and blood urea were significantly greater. Ura excretion was also higher in PPG-treated rats when compared with control rats. These data suggest a stimulation of ureagenesis in PPG-treated rats. The inhibition of gamma-cystathionase was reflected in the blood levels of amino acids, because the L-methionine: L-cyst(e)ine ratio was significantly higher in PPG-treated rats than in control rats; blood concentration of cystathionine was also greater. Histological examination of liver and kidney showed no changes in PPG-treated rats when compared with controls. The administration of N-acetylcysteine (NAC) to PPG-treated rats reversed the changes in blood urea and in liver GSH. These data suggest that when liver L-cysteine production was impaired by the blockage of the trans-sulfuration pathway, the concentration of this amino acid was maintained mainly by an increase in protein degradation and by a depletion in GSH concentration that may spare L-cysteine.
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Affiliation(s)
- A Triguero
- Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Spain
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46
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Berkowitz DB, Jahng WJ, Pedersen ML. α-VINYLLYSINE AND α-VINYLARGININE ARE TIME-DEPENDENT INHIBITORS OF THEIR COGNATE DECARBOXYLASES. Bioorg Med Chem Lett 1996; 6:2151-2156. [PMID: 29123334 DOI: 10.1016/0960-894x(96)00366-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
(±)-α-Vinyllysine and (±)-α-vinylarginine display time-dependent inhibition of L-lysine decarboxylase from B. cadaveris, and L-arginine decarboxylase from E. coli, respectively. A complete Kitz-Wilson analysis has been performed using a modification of the Palcic continuous UV assay for decarboxylase activity.
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Affiliation(s)
- David B Berkowitz
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304
| | - Wan-Jin Jahng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304
| | - Michelle L Pedersen
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304
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Berkowitz DB, Smith MK. A Convenient Synthesis of L-α-Vinylglycine from L-Homoserine Lactone. SYNTHESIS-STUTTGART 1996; 1996:39-41. [PMID: 29962541 PMCID: PMC6022833 DOI: 10.1055/s-1996-4177] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A procedure for the synthesis of L-α-vinylglycine from L-homoserine lactone is described. The route developed is convenient (only one chromatography step is required) and efficient (72% yield; ≥95% optical yield over 4 steps). Key features include the use of acid-labile protecting groups for the amino (Boc) and carboxyl (diphenylmethyl ester) groups, and the use of the phenylselenolate equivalent derived from sodium borohydride and diphenyl diselenide for L-homoserine lactone cleavage.
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Affiliation(s)
- David B Berkowitz
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, Fax + 1(402)4729402
| | - Marianne K Smith
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, Fax + 1(402)4729402
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Sanders MM, Kon C. Glutamine and glutamate metabolism in normal and heat shock conditions inDrosophila Kc cells: Conditions supporting glutamine synthesis maximize heat shock polypeptide expression. J Cell Physiol 1992; 150:620-31. [PMID: 1347046 DOI: 10.1002/jcp.1041500323] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have previously reported that Drosophila Kc cells require glutamine for maximal expression of heat shock proteins in stressed conditions (Sanders and Kon: J. Cell. Physiol. 146:180-190, 1991). The mechanism of this effect has been investigated by comparing the metabolic utilization of glutamine in conditions which support hsp expression with that of glutamate in conditions where up to 100-fold less hsp is synthesized. This comparison showed that free ammonia was generated by cells incubated in the presence of glutamine in 37 degrees C (heat shock) conditions, but not at 25 degrees C, and not in the presence of glutamate in either normal or heat shock conditions. There was no difference in the amount of [14C]O2 generated from either [14C]-labeled amino acid in the tricarboxylic acid cycle, but three- to four-fold more alanine was synthesized in cells incubated in glutamine than in glutamate. Treating the cells with aminotransferase inhibitors to artificially increase NH3 release raised hsp expression in the presence of glutamate to maximal levels characteristic of glutamine. This potentiation correlated with inhibition of alanine aminotransferase. Since only NH3 production correlated with hsp expression in heat shock conditions in the presence of glutamine, and NH3 addition to glutamate also resulted in maximal hsp expression, we measured glutamine production in glutamate plus NH3 and observed net glutamine synthesis. The supposition that glutamine itself is responsible for the regulatory changes supporting maximal hsp expression was supported by the finding that the glutamine analog, 6-diazo-5-oxo-L-norleucine (DON), mimicked the effects of glutamine. We conclude that glutamine imposes regulatory changes which alter nitrogen metabolism and support hsp expression in Kc cells.
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Affiliation(s)
- M M Sanders
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854
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Daumas M, Vo-Quang L, Le Goffic F. New non-proteogenic aminoacids bearing an enol aryl-ether moiety. Tetrahedron 1992. [DOI: 10.1016/s0040-4020(01)88758-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Berkowitz DB. A New Method for the α-Vinylation of Protected α-Amino Acids; Ethylene Oxide as Vinyl Cation Equivalent. SYNTHETIC COMMUN 1990. [DOI: 10.1080/00397919008053106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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