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Sekine M, Fujiwara M, Okamoto K, Ichida K, Nagata K, Hille R, Nishino T. Significance and amplification methods of the purine salvage pathway in human brain cells. J Biol Chem 2024; 300:107524. [PMID: 38960035 PMCID: PMC11342100 DOI: 10.1016/j.jbc.2024.107524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 07/05/2024] Open
Abstract
Previous studies suggest that uric acid or reactive oxygen species, products of xanthine oxidoreductase (XOR), may associate with neurodegenerative diseases. However, neither relationship has ever been firmly established. Here, we analyzed human brain samples, obtained under protocols approved by research ethics committees, and found no expression of XOR and only low levels of uric acid in various regions of the brain. In the absence of XOR, hypoxanthine will be preserved and available for incorporation into the purine salvage pathway. To clarify the importance of salvage in the brain, we tested using human-induced pluripotent stem cell-derived neuronal cells. Stable isotope analyses showed that the purine salvage pathway was more effective for ATP synthesis than purine de novo synthesis. Blood uric acid levels were related to the intracellular adenylate pool (ATP + ADP + AMP), and reduced levels of this pool result in lower uric acid levels. XOR inhibitors are related to extracellular hypoxanthine levels available for uptake into the purine salvage pathway by inhibiting the oxidation of hypoxanthine to xanthine and uric acid in various organs where XOR is present and can prevent further decreases in the intracellular adenylate pool under stress. Furthermore, adding precursors of the pentose phosphate pathway enhanced hypoxanthine uptake, indicating that purine salvage is activated by phosphoribosyl pyrophosphate replenishment. These findings resolve previous contradictions regarding XOR products and provide new insights into clinical studies. It is suggested that therapeutic strategies maximizing maintenance of intracellular adenylate levels may effectively treat pathological conditions associated with ischemia and energy depletion.
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Affiliation(s)
- Mai Sekine
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Science, The University of Tokyo, Bunkyo, Tokyo, Japan; Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan.
| | - Megumi Fujiwara
- Department of Laboratory of Morphological Analysis, Nippon Medical School, Bunkyo, Tokyo, Japan
| | - Ken Okamoto
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Koji Nagata
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Russ Hille
- Department of Biochemistry, University of California, Riverside, California, USA
| | - Takeshi Nishino
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Science, The University of Tokyo, Bunkyo, Tokyo, Japan; Professor Emeritus, Nippon Medical School, Bunkyo, Tokyo, Japan; University of Tokyo Health Sciences, Tama, Tokyo, Japan.
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2
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Astroglial CB1 receptors, energy metabolism, and gliotransmission: an integrated signaling system? Essays Biochem 2023; 67:49-61. [PMID: 36645029 DOI: 10.1042/ebc20220089] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 01/17/2023]
Abstract
Astrocytes are key players in brain homeostasis and function. During the last years, several studies have cemented this notion by showing that these cells respond to neuronal signals and, via the release of molecules that modulate and support synaptic activity (gliotransmission) participates in the functions of the so-called tripartite synapse. Thus, besides their established control of brain metabolism, astrocytes can also actively control synaptic activity and behavior. Among the signaling pathways that shape the functions of astrocyte, the cannabinoid type-1 (CB1) receptor is emerging as a critical player in the control of both gliotransmission and the metabolic cooperation between astrocytes and neurons. In the present short review, we describe known and newly discovered properties of the astroglial CB1 receptors and their role in modulating brain function and behavior. Based on this evidence, we finally discuss how the functions and mode of actions of astrocyte CB1 receptors might represent a clear example of the inextricable relationship between energy metabolism and gliotransmission. These tight interactions will need to be taken into account for future research in astrocyte functions and call for a reinforcement of the theoretical and experimental bridges between studies on metabolic and synaptic functions of astrocytes.
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3
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Gessner P, Lum J, Frenguelli BG. The mammalian purine salvage pathway as an exploitable route for cerebral bioenergetic support after brain injury. Neuropharmacology 2023; 224:109370. [PMID: 36493858 DOI: 10.1016/j.neuropharm.2022.109370] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/21/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022]
Abstract
Purine-based molecules play ancient, fundamental, and evolutionarily-conserved roles across life on Earth, ranging from DNA and RNA, to the universal energy currency, ATP. In mammals, the two primary routes for the synthesis of the adenine nucleotides ATP, ADP and AMP, and, as a consequence, the major bioactive metabolite adenosine, are the de novo purine biosynthesis (DNPB) pathway, and the purine salvage pathway (PSP). Of the two, the PSP dominates in both the mammalian brain and heart. This is because the PSP utilizes the breakdown products of ATP, occasioned by the high energy demands of these organs, to rapidly regenerate adenine nucleotides. This resynthesis route, while efficient and energetically favourable, leaves these organs vulnerable to loss of salvageable metabolites, with the potential for protracted depletion of the means to synthesize ATP, and the ability to deploy neuro- and cardioprotective adenosine. Having previously shown that hippocampal cellular ATP and adenosine release can be increased by supplying substrates for the PSP (d-ribose and adenine), we now explore the expression of DNPB and PSP enzymes in hippocampal neurons and astrocytes based on available transcriptomic data. We find that key enzymes of the PSP are expressed at higher levels than those in the DNPB pathway, and that PSP enzymes are expressed at higher levels in neurons than in astrocytes. These data reflect the importance of the PSP in the mammalian brain and imply that pharmacological targeting of the PSP may be particularly beneficial to neurons at times of metabolic stress. This article is part of the Special Issue on 'Purinergic Signaling: 50 years'.
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Affiliation(s)
- Philipp Gessner
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Jenni Lum
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
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4
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Chen MM, Guo W, Chen SM, Guo XZ, Xu L, Ma XY, Wang YX, Xie C, Meng LH. Xanthine dehydrogenase rewires metabolism and the survival of nutrient deprived lung adenocarcinoma cells by facilitating UPR and autophagic degradation. Int J Biol Sci 2023; 19:772-788. [PMID: 36778128 PMCID: PMC9909990 DOI: 10.7150/ijbs.78948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/09/2022] [Indexed: 01/11/2023] Open
Abstract
Xanthine dehydrogenase (XDH) is the rate-limiting enzyme in purine catabolism by converting hypoxanthine to xanthine and xanthine to uric acid. The altered expression and activity of XDH are associated with the development and prognosis of multiple types of cancer, while its role in lung adenocarcinoma (LUAD) remains unknown. Herein, we demonstrated that XDH was highly expressed in LUAD and was significantly correlated with poor prognosis. Though inhibition of XDH displayed moderate effect on the viability of LUAD cells cultured in the complete medium, it significantly attenuated the survival of starved cells. Similar results were obtained in XDH-knockout cells. Nucleosides supplementation rescued the survival of starved LUAD cells upon XDH inhibition, while inhibition of purine nucleoside phosphorylase abrogated the process, indicating that nucleoside degradation is required for the XDH-mediated survival of LUAD cells. Accordingly, metabolic flux revealed that ribose derived from nucleoside fueled key carbon metabolic pathways to sustain the survival of starved LUAD cells. Mechanistically, down-regulation of XDH suppressed unfolded protein response (UPR) and autophagic flux in starved LUAD cells. Inhibition of XDH decreased the level of amino acids produced by autophagic degradation, which was accompanied with down-regulation of mTORC1 signaling. Supplementation of amino acids including glutamine or glutamate rescued the survival of starved LUAD cells upon knockout or inhibition of XDH. Finally, XDH inhibitors potentiated the anti-cancer activity of 2-deoxy-D-glucose that induced UPR and/or autophagy in vitro and in vivo. In summary, XDH plays a crucial role in the survival of starved LUAD cells and targeting XDH may improve the efficacy of drugs that induce UPR and autophagy in the therapy of LUAD.
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Affiliation(s)
- Man-Man Chen
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Guo
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Si-Meng Chen
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China
| | - Xiao-Zhen Guo
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China
| | - Lan Xu
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China
| | - Xiao-Yu Ma
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Xiang Wang
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China
| | - Cen Xie
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ling-Hua Meng
- Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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5
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Georgoulis I, Bock C, Lannig G, Pörtner HO, Feidantsis K, Giantsis IA, Sokolova IM, Michaelidis B. Metabolic remodeling caused by heat hardening in the Mediterranean mussel Mytilus galloprovincialis. J Exp Biol 2022; 225:285988. [PMID: 36426666 DOI: 10.1242/jeb.244795] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/18/2022] [Indexed: 11/27/2022]
Abstract
Organisms can modify and increase their thermal tolerance faster and more efficiently after a brief exposure to sublethal thermal stress. This response is called 'heat hardening' as it leads to the generation of phenotypes with increased heat tolerance. The aim of this study was to investigate the impact of heat hardening on the metabolomic profile of Mytilus galloprovincialis in order to identify the associated adjustments of biochemical pathways that might benefit the mussels' thermal tolerance. Thus, mussels were exposed sequentially to two different phases (heat hardening and acclimation phases). To gain further insight into the possible mechanisms underlying the metabolic response of the heat-hardened M. galloprovincialis, metabolomics analysis was complemented by the estimation of mRNA expression of phosphoenolpyruvate carboxykinase (PEPCK), pyruvate kinase (PK) and alternative oxidase (AOX) implicated in the metabolic pathways of gluconeogenesis, glycolysis and redox homeostasis, respectively. Heat-hardened mussels showed evidence of higher activity of the tricarboxylic acid (TCA) cycle and diversification of upregulated metabolic pathways, possibly as a mechanism to increase ATP production and extend survival under heat stress. Moreover, formate and taurine accumulation provide an antioxidant and cytoprotective role in mussels during hypoxia and thermal stress. Overall, the metabolic responses in non-heat-hardened and heat-hardened mussels underline the upper thermal limits of M. galloprovincialis, set at 26°C, and are in accordance with the OCLTT concept. The ability of heat-hardened mussels to undergo a rapid gain and slow loss of heat tolerance may be an advantageous strategy for coping with intermittent and often extreme temperatures.
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Affiliation(s)
- Ioannis Georgoulis
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
| | - Christian Bock
- Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research, Integrative Ecophysiology, Postfach 120161, D-27515 Bremerhaven, Germany
| | - Gisela Lannig
- Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research, Integrative Ecophysiology, Postfach 120161, D-27515 Bremerhaven, Germany
| | - Hans-O Pörtner
- Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research, Integrative Ecophysiology, Postfach 120161, D-27515 Bremerhaven, Germany
| | - Konstantinos Feidantsis
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
| | - Ioannis A Giantsis
- Department of Animal Science, Faculty of Agricultural Sciences, University of Western Macedonia, GR-53100 Florina, Greece
| | - Inna M Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, D-18055 Rostock, Germany
| | - Basile Michaelidis
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
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6
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Kaya D, Micili SC, Kizmazoglu C, Mucuoglu AO, Buyukcoban S, Ersoy N, Yilmaz O, Isik AT. Allopurinol attenuates repeated traumatic brain injury in old rats: A preliminary report. Exp Neurol 2022; 357:114196. [PMID: 35931122 DOI: 10.1016/j.expneurol.2022.114196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 07/13/2022] [Accepted: 07/31/2022] [Indexed: 12/01/2022]
Abstract
Traumatic brain injury (TBI) is an overlooked cause of morbidity, which was shown to accelerate inflammation, oxidative stress, and neuronal cell loss and is associated with spatial learning and memory impairments and some psychiatric disturbances in older adults. However, there is no effective treatment in order to offer a favorable outcome encompassing a good recovery after TBI in older adults. Hence, the present study aimed to investigate the histological and neurobehavioral effects of Allopurinol (ALL) in older rats that received repeated TBI (rTBI). For this purpose, a weight-drop rTBI model was used on old male Wistar rats. Rats received 5 repeated TBI/sham injuries 24 h apart and were treated with saline or Allopurinol 100 mg/kg, i.p. each time. They were randomly assigned to three groups: control group (no injury); rTBI group (received 5 rTBI and treated with saline); rTBI+ALL group (received 5 rTBI and treated with Allopurinol). Then, half of the animals from each group were sacrificed on day 6 and the remaining animals were assessed with Open field, Elevated plus maze and Morris Water Maze test. Basic neurological tasks were evaluated with neurological assessment protocol every other day until after the 19th day from the last injury. Brain sections were processed for neuronal cell count in the hippocampus (CA1), dentate gyrus (DG), and prefrontal cortex (PC). Also, an immunohistochemical assay was performed to determine NeuN, iNOS, and TNFα levels in the brain regions. The number of neurons was markedly reduced in CA1, GD, and PC in rats receiving saline compared to those receiving allopurinol treatment. Immunohistochemical analysis showed marked induction of iNOS and TNFα expression in the brain tissues which were reduced after allopurinol at 6 and 19 days post-injury. Also, ALL-treated rats demonstrated a remarkable induce in NeuN expression, indicating a reduction in rTBI-induced neuronal cell death. In neurobehavioral analyses, time spent in closed arms, in the corner of the open field, swimming latency, and distance were impaired in injured rats; however, all of them were significantly improved by allopurinol therapy. To sum up, this study demonstrated that ALL may mitigate rTBI-induced damage in aged rats, which suggests ALL as a potential therapeutic strategy for the treatment of recurrent TBI.
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Affiliation(s)
- Derya Kaya
- Dokuz Eylul University Faculty of Medicine, Department of Geriatric Medicine, Unit for Brain Aging and Dementia, Izmir, Turkey; Geriatric Science Association, Izmir, Turkey.
| | - Serap Cilaker Micili
- Dokuz Eylul University Faculty of Medicine, Department of Histology and Embryology, Izmir, Turkey
| | - Ceren Kizmazoglu
- Dokuz Eylul University Faculty of Medicine, Department of Neurosurgery, Izmir, Turkey
| | - Ali Osman Mucuoglu
- Dokuz Eylul University Faculty of Medicine, Department of Neurosurgery, Izmir, Turkey
| | - Sibel Buyukcoban
- Dokuz Eylul University Faculty of Medicine, Department of Anaesthesiology and Reanimation, İzmir, Turkey
| | - Nevin Ersoy
- Dokuz Eylul University Faculty of Medicine, Department of Histology and Embryology, Izmir, Turkey
| | - Osman Yilmaz
- Dokuz Eylul University Health Sciences Institute, Department of Laboratory Animal Science, Izmir, Turkey
| | - Ahmet Turan Isik
- Dokuz Eylul University Faculty of Medicine, Department of Geriatric Medicine, Unit for Brain Aging and Dementia, Izmir, Turkey; Geriatric Science Association, Izmir, Turkey
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7
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Lu Z, Li S, Aa N, Zhang Y, Zhang R, Xu C, Zhang S, Kong X, Wang G, Aa J, Zhang Y. Quantitative analysis of 20 purine and pyrimidine metabolites by HILIC-MS/MS in the serum and hippocampus of depressed mice. J Pharm Biomed Anal 2022; 219:114886. [PMID: 35715372 DOI: 10.1016/j.jpba.2022.114886] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/01/2022]
Abstract
Purine and pyrimidine metabolism are vital metabolic pathways in the development, proliferation or repairment of cells or tissues associated with various diseases. Here, a simple, all-in-one injection hydrophilic interaction liquid chromatography-tandem mass spectrometry method was developed for simultaneous determination of 20 metabolites: adenine, adenosine, deoxyadenosine, adenosine 5'-monophosphate, cyclic adenosine monophosphate, hypoxanthine, xanthine, inosine, deoxyinosine, xanthosine, xanthosine 5'-monophosphate and uric acid, which are products of purine metabolism; uridine, deoxyuridine, uridine 5'-monophosphate and uracil, are products of pyrimidine metabolism; and corticosterone, methionine, acetylcholine and serotonin. To minimize interference of endogenous molecules in sample matrixes, a combination of activated carbon adsorption and a serum substitute matrix (5% bovine serum albumin in phosphate buffered saline) was utilized and jointly applied. The sensitivity, linearity, stability, precision, accuracy and extraction recovery were evaluated, and the method was demonstrated to be accurate, sensitive and reliable. An analytical strategy was successfully applied to quantitatively determine 20 metabolite levels in the serum and hippocampus of mice with chronic social defeat stress-induced depression. The results showed greatly perturbed purine metabolism in the depressed mice, which was primarily characterized by dramatic increases in hypoxanthine, xanthine and inosine in serum and reduced levels of adenine, adenosine and adenosine 5'-monophosphate in the hippocampus. These findings suggest that this novel strategy can facilitate the quantitative analysis of adenine and other purine and pyrimidine metabolites in tissue and serum and exhibits great potential in the exploration of metabolism-related mechanisms of relevant diseases.
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Affiliation(s)
- Zhenyao Lu
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Sijia Li
- Department of Pharmacy, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Nan Aa
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210009, China
| | - Yuanmao Zhang
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Ran Zhang
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Chen Xu
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Shize Zhang
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Xiangqing Kong
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210009, China
| | - Guangji Wang
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Jiye Aa
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
| | - Yue Zhang
- Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
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Rimmele TS, Li S, Andersen JV, Westi EW, Rotenberg A, Wang J, Aldana BI, Selkoe DJ, Aoki CJ, Dulla CG, Rosenberg PA. Neuronal Loss of the Glutamate Transporter GLT-1 Promotes Excitotoxic Injury in the Hippocampus. Front Cell Neurosci 2022; 15:788262. [PMID: 35035352 PMCID: PMC8752461 DOI: 10.3389/fncel.2021.788262] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/08/2021] [Indexed: 12/26/2022] Open
Abstract
GLT-1, the major glutamate transporter in the mammalian central nervous system, is expressed in presynaptic terminals that use glutamate as a neurotransmitter, in addition to astrocytes. It is widely assumed that glutamate homeostasis is regulated primarily by glutamate transporters expressed in astrocytes, leaving the function of GLT-1 in neurons relatively unexplored. We generated conditional GLT-1 knockout (KO) mouse lines to understand the cell-specific functions of GLT-1. We found that stimulus-evoked field extracellular postsynaptic potentials (fEPSPs) recorded in the CA1 region of the hippocampus were normal in the astrocytic GLT-1 KO but were reduced and often absent in the neuronal GLT-1 KO at 40 weeks. The failure of fEPSP generation in the neuronal GLT-1 KO was also observed in slices from 20 weeks old mice but not consistently from 10 weeks old mice. Using an extracellular FRET-based glutamate sensor, we found no difference in stimulus-evoked glutamate accumulation in the neuronal GLT-1 KO, suggesting a postsynaptic cause of the transmission failure. We hypothesized that excitotoxicity underlies the failure of functional recovery of slices from the neuronal GLT-1 KO. Consistent with this hypothesis, the non-competitive NMDA receptor antagonist MK801, when present in the ACSF during the recovery period following cutting of slices, promoted full restoration of fEPSP generation. The inclusion of an enzymatic glutamate scavenging system in the ACSF conferred partial protection. Excitotoxicity might be due to excess release or accumulation of excitatory amino acids, or to metabolic perturbation resulting in increased vulnerability to NMDA receptor activation. Previous studies have demonstrated a defect in the utilization of glutamate by synaptic mitochondria and aspartate production in the synGLT-1 KO in vivo, and we found evidence for similar metabolic perturbations in the slice preparation. In addition, mitochondrial cristae density was higher in synaptic mitochondria in the CA1 region in 20–25 weeks old synGLT-1 KO mice in the CA1 region, suggesting compensation for loss of axon terminal GLT-1 by increased mitochondrial efficiency. These data suggest that GLT-1 expressed in presynaptic terminals serves an important role in the regulation of vulnerability to excitotoxicity, and this regulation may be related to the metabolic role of GLT-1 expressed in glutamatergic axon terminals.
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Affiliation(s)
- Theresa S Rimmele
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States
| | - Shaomin Li
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Jens Velde Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Rotenberg
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States.,Program in Neuroscience, Harvard Medical School, Boston, MA, United States
| | - Jianlin Wang
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States
| | - Blanca Irene Aldana
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Chiye J Aoki
- Center for Neural Science, New York University, NY, United States.,Neuroscience Institute NYU Langone Medical Center, NY, United States
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Paul Allen Rosenberg
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States.,Program in Neuroscience, Harvard Medical School, Boston, MA, United States
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9
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Hu YR, Xing SL, Chen C, Shen DZ, Chen JL. Codonopsis pilosula Polysaccharides Alleviate Aβ 1-40-Induced PC12 Cells Energy Dysmetabolism via CD38/NAD+ Signaling Pathway. Curr Alzheimer Res 2021; 18:208-221. [PMID: 34102973 PMCID: PMC8506921 DOI: 10.2174/1567205018666210608103831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 03/16/2021] [Accepted: 04/21/2021] [Indexed: 11/22/2022]
Abstract
Background Alzheimer's disease (AD) is the most common type of dementia and has a complex pathogenesis with no effective treatment. Energy metabolism disorders, as an early pathological event of AD,have attracted attention as a promising area of AD research. Codonopsis pilosula Polysaccharides are the main effective components of Codonopsis pilosula, which have been demonstrated to regulate energy metabolism. Methods In order to further study the roles and mechanisms of Codonopsis pilosula polysaccharides in AD, this study used an Aβ1-40-induced PC12 cells model to study the protective effects of Codonopsis pilosula polysaccharides and their potential mechanisms in improving energy metabolism dysfunction. Results The results showed that Aβ1-40 induced a decrease in PC12 cells viability, energy metabolism molecules (ATP, NAD+, and NAD+/NADH) and Mitochondrial Membrane Potential (MMP) and an increase in ROS. Additionally, it was found that Aβ1-40 increased CD38 expression related to NAD+ homeostasis, whereas Silent Information Regulation 2 homolog1 (SIRT1, SIRT3), Peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and SIRT3 activity were decreased. Codonopsis pilosula polysaccharides increased NAD+, NAD+/NADH, SIRT3, SIRT1, and PGC-1α related to NAD+, thus partially recovering ATP. Conclusion Our findings reveal that Codonopsis pilosula polysaccharides protected PC12 cells from Aβ1-40-induced damage, suggesting that these components of the Codonopsis pilosula herb may represent an early treatment option for AD patients.
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Affiliation(s)
- Yi R Hu
- Shanghai Geriatric Institute of Chinese Medicine, Shanghai 200031, China
| | - San L Xing
- Shanghai Geriatric Institute of Chinese Medicine, Shanghai 200031, China
| | - Chuan Chen
- Shanghai Geriatric Institute of Chinese Medicine, Shanghai 200031, China
| | - Ding Z Shen
- Shanghai Geriatric Institute of Chinese Medicine, Shanghai 200031, China
| | - Jiu L Chen
- Shanghai Geriatric Institute of Chinese Medicine, Shanghai 200031, China
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10
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Singer KE, Wallen TE, Morris MC, McGlone E, Stevens-Topie S, Earnest R, Goodman MD. Postinjury treatments to make early tactical aeromedical evacuation practical for the brain after TBI. J Trauma Acute Care Surg 2021; 91:S89-S98. [PMID: 33938511 DOI: 10.1097/ta.0000000000003259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Traumatic brain injury (TBI) is common in civilians and military personnel. No potential therapeutics have been evaluated to prevent secondary injury induced by the hypobaric hypoxia (HH) environment integral to postinjury aeromedical evacuation (AE). We examined the role of allopurinol, propranolol, adenosine/lidocaine/magnesium (ALM), or amitriptyline administration prior to simulated flight following murine TBI. METHODS Mice underwent TBI and were given allopurinol, propranolol, amitriptyline, or ALM prior to simulated AE or normobaric normoxia (NN) control. Heart rate (HR), respiratory rate, and oxygen saturation (Spo2) were recorded throughout simulated AE. Mice were sacrificed at 24 hours, 7 days, or 30 days. Serum and cerebral cytokines were assessed by enzyme-linked immunosorbent assay. Motor function testing was performed with Rotarod ambulation. Immunohistochemistry was conducted to examine phosphorylated tau (p-tau) accumulation in the hippocampus at 30 days. RESULTS While all treatments improved oxygen saturation, propranolol, amitriptyline, and allopurinol improved AE-induced tachycardia. At 24 hours, both propranolol and amitriptyline reduced tumor necrosis factor alpha levels while allopurinol and ALM reduced tumor necrosis factor alpha levels only in NN mice. Propranolol, amitriptyline, and ALM demonstrated lower serum monocyte chemoattractant protein-1 7 days after AE. Both amitriptyline and allopurinol improved Rotarod times for AE mice while only allopurinol improved Rotarod times for NN mice. Propranolol was able to reduce p-tau accumulation under both HH and NN conditions while ALM only reduced p-tau in hypobaric hypoxic conditions. CONCLUSION Propranolol lowered post-TBI HR with reduced proinflammatory effects, including p-tau reduction. Amitriptyline-induced lower post-TBI HR and improved functional outcomes without affecting inflammatory response. Allopurinol did not affect vital signs but improved late post-TBI systemic inflammation and functional outcomes. Adenosine/lidocaine/magnesium provided no short-term improvements but reduced p-tau accumulation at 30 days in the HH cohort. Allopurinol may be the best of the four treatments to help prevent short-term functional deficits while propranolol may address long-term effects. LEVEL OF EVIDENCE Basic science article.
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Affiliation(s)
- Kathleen E Singer
- From the Department of General Surgery, University of Cincinnati, Cincinnati Ohio
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11
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Young GH, Lin JT, Cheng YF, Ho CF, Kuok QY, Hsu RC, Liao WR, Chen CC, Chen HM. Modulation of adenine phosphoribosyltransferase-mediated salvage pathway to accelerate diabetic wound healing. FASEB J 2021; 35:e21296. [PMID: 33675115 DOI: 10.1096/fj.202001736rr] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 01/13/2023]
Abstract
Adenine phosphoribosyltransferase (APRT) is the key enzyme involved in purine salvage by the incorporation of adenine and phosphoribosyl pyrophosphate to provide adenylate nucleotides. To evaluate the role of APRT in the repair processes of cutaneous wounds in healthy skin and in diabetic patients, a diabetic mouse model (db/db) and age-matched wild-type mice were used. Moreover, the topical application of adenine was assessed. In vitro studies, analytical, histological, and immunohistochemical methods were used. Diabetic mice treated with adenine exhibited elevated ATP levels in organismic skin and accelerated wound healing. In vitro studies showed that APRT utilized adenine to rescue cellular ATP levels and proliferation from hydrogen peroxide-induced oxidative damage. HPLC-ESI-MS/MS-based analysis of total adenylate nucleotides in NIH-3T3 fibroblasts demonstrated that adenine addition enlarged the cellular adenylate pool, reduced the adenylate energy charge, and provided additional AMP for the further generation of ATP. These data indicate an upregulation of APRT in skin wounds, highlighting its role during the healing of diabetic wounds through regulation of the nucleotide pool after injury. Furthermore, topical adenine supplementation resulted in an enlargement of the adenylate pool needed for the generation of ATP, an important molecule for wound repair.
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Affiliation(s)
| | | | | | | | | | - Ru-Chun Hsu
- Energenesis Biomedical Co. Ltd, Taipei, Taiwan
| | | | | | - Han-Min Chen
- Energenesis Biomedical Co. Ltd, Taipei, Taiwan.,Department of Life Science, Institute of Applied Science and Engineering, Catholic Fu-Jen University, New Taipei City, Taiwan
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12
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Sharma S, Tiarks G, Haight J, Bassuk AG. Neuropathophysiological Mechanisms and Treatment Strategies for Post-traumatic Epilepsy. Front Mol Neurosci 2021; 14:612073. [PMID: 33708071 PMCID: PMC7940684 DOI: 10.3389/fnmol.2021.612073] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/26/2021] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death in young adults and a risk factor for acquired epilepsy. Severe TBI, after a period of time, causes numerous neuropsychiatric and neurodegenerative problems with varying comorbidities; and brain homeostasis may never be restored. As a consequence of disrupted equilibrium, neuropathological changes such as circuit remodeling, reorganization of neural networks, changes in structural and functional plasticity, predisposition to synchronized activity, and post-translational modification of synaptic proteins may begin to dominate the brain. These pathological changes, over the course of time, contribute to conditions like Alzheimer disease, dementia, anxiety disorders, and post-traumatic epilepsy (PTE). PTE is one of the most common, devastating complications of TBI; and of those affected by a severe TBI, more than 50% develop PTE. The etiopathology and mechanisms of PTE are either unknown or poorly understood, which makes treatment challenging. Although anti-epileptic drugs (AEDs) are used as preventive strategies to manage TBI, control acute seizures and prevent development of PTE, their efficacy in PTE remains controversial. In this review, we discuss novel mechanisms and risk factors underlying PTE. We also discuss dysfunctions of neurovascular unit, cell-specific neuroinflammatory mediators and immune response factors that are vital for epileptogenesis after TBI. Finally, we describe current and novel treatments and management strategies for preventing PTE.
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Affiliation(s)
- Shaunik Sharma
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Grant Tiarks
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Joseph Haight
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Alexander G Bassuk
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
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13
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Purines: From Diagnostic Biomarkers to Therapeutic Agents in Brain Injury. Neurosci Bull 2020; 36:1315-1326. [PMID: 32542580 DOI: 10.1007/s12264-020-00529-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/30/2020] [Indexed: 12/12/2022] Open
Abstract
The purines constitute a family of inter-related compounds that serve a broad range of important intracellular and extracellular biological functions. In particular, adenosine triphosphate (ATP) and its metabolite and precursor, adenosine, regulate a wide variety of cellular and systems-level physiological processes extending from ATP acting as the cellular energy currency, to the adenosine arising from the depletion of cellular ATP and responding to reduce energy demand and hence to preserve ATP during times of metabolic stress. This inter-relationship provides opportunities for both the diagnosis of energy depletion during conditions such as stroke, and the replenishment of ATP after such events. In this review we address these opportunities and the broad potential of purines as diagnostics and restorative agents.
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Zheng F, Zhou YT, Feng DD, Li PF, Tang T, Luo JK, Wang Y. Metabolomics analysis of the hippocampus in a rat model of traumatic brain injury during the acute phase. Brain Behav 2020; 10:e01520. [PMID: 31908160 PMCID: PMC7010586 DOI: 10.1002/brb3.1520] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/26/2019] [Accepted: 12/02/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) has increased in rank among traumatic injuries worldwide. Traumatic brain injury is a serious obstacle given that its complex pathology represents a long-term process. Recently, systems biology strategies such as metabolomics to investigate the multifactorial nature of TBI have facilitated attempts to find biomarkers and probe molecular pathways for its diagnosis and therapy. METHODS This study included a group of 20 rats with controlled cortical impact and a group of 20 sham rats. We utilized mNSS tests to investigate neurological metabolic impairments on day 1 and day 3. Furthermore, we applied metabolomics and bioinformatics to determine the metabolic perturbation caused by TBI during the acute period in the hippocampus tissue of controlled cortical impact (CCI) rats. Notably, TBI-protein-metabolite subnetworks identified from a database were assessed for associations between metabolites and TBI by the dysregulation of related enzymes and transporters. RESULTS Our results identified 7 and 8 biomarkers on day 1 and day 3, respectively. Additionally, related pathway disorders showed effects on arginine and proline metabolism as well as taurine and hypotaurine metabolism on day 3 in acute TBI. Furthermore, according to metabolite-protein database searches, 25 metabolite-protein pairs were established as causally associated with TBI. Further, bioinformation indicated that these TBI-associated proteins mainly take part in 5'-nucleotidase activity and carboxylic acid transmembrane transport. In addition, interweaved networks were constructed to show that the development of TBI might be affected by metabolite-related proteins and their protein pathways. CONCLUSION The overall results show that acute TBI is susceptible to metabolic disorders, and the joint metabolite-protein network analysis provides a favorable prediction of TBI pathogenesis mechanisms in the brain. The signatures in the hippocampus might be promising for the development of biomarkers and pathways relevant to acute TBI and could further guide testable predictions of the underlying mechanism of TBI.
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Affiliation(s)
- Fei Zheng
- College of Electrical and Information Engineering, Hunan University, Changsha, China
| | - Yan-Tao Zhou
- College of Electrical and Information Engineering, Hunan University, Changsha, China
| | - Dan-Dan Feng
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Peng-Fei Li
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Tao Tang
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Jie-Kun Luo
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Yang Wang
- Laboratory of Ethnopharmacology, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha, China
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15
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Schober ME, Requena DF, Maschek JA, Cox J, Parra L, Lolofie A. Effects of controlled cortical impact and docosahexaenoic acid on rat pup fatty acid profiles. Behav Brain Res 2020; 378:112295. [PMID: 31618622 PMCID: PMC6897326 DOI: 10.1016/j.bbr.2019.112295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/23/2019] [Accepted: 10/08/2019] [Indexed: 12/15/2022]
Abstract
Traumatic brain injury (TBI) is the leading cause of acquired neurologic disability in children, particularly in those under four years old. During this period, rapid brain growth demands higher Docosahexaenoic Acid (DHA) intake. DHA is an essential fatty acid and brain cell component derived almost entirely from the diet. DHA improved neurologic outcomes and decreased inflammation after controlled cortical impact (CCI) in 17-day old (P17) rats, our established model of pediatric TBI. In adult rodents, TBI decreases brain DHA. We hypothesized that CCI would decrease rat brain DHA at post injury day (PID) 60, blunted by 0.1% DHA diet. We quantitated fatty acids using Gas Chromatography-Mass Spectrometry. We provided 0.1% DHA before CCI to ensure high DHA in dam milk. We compared brain DHA in rats after 60 days of regular (REG) or DHA diet to SHAM pups on REG diet. Brain DHA decreased in REGCCI, not in DHACCI, relative to SHAMREG. In a subsequent experiment, we gave rat pups DHA or vehicle intraperitoneally after CCI followed by DHA or REG diet for 60 days. REG increased brain Docosapentaenoic Acid (n-6 DPA, a brain DHA deficiency marker) relative to SHAMDHA and DHACCI pups (p < 0.001, diet effect). DHA diet nearly doubled DHA and decreased n-6 DPA in blood but did not increase brain DHA content (p < 0.0001, diet effect). We concluded that CCI or craniotomy alone induces a mild DHA deficit as shown by increased brain DPA.
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Affiliation(s)
- Michelle E Schober
- Department of Pediatrics, Division of Critical Care, Salt Lake City, UT, 84132, United States.
| | - Daniela F Requena
- Department of Pediatrics, Division of Critical Care, Salt Lake City, UT, 84132, United States.
| | - J Alan Maschek
- Metabolomics, Mass Spectrometry and Proteomics Core of the University of Utah, Salt Lake City, UT, 84132, United States.
| | - James Cox
- Department of Biochemistry, Salt Lake City, UT, 84132, United States; Diabetes and Metabolism Research Center, Salt Lake City, UT, 84132, United States; Metabolomics, Mass Spectrometry and Proteomics Core of the University of Utah, Salt Lake City, UT, 84132, United States.
| | - Leonardo Parra
- Department of Biology, Howard Hughes Medical Institute, Salt Lake City, UT, 84132, United States.
| | - Alyssa Lolofie
- Department of Pediatrics, Division of Critical Care, Salt Lake City, UT, 84132, United States.
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Hall J, Frenguelli BG. The combination of ribose and adenine promotes adenosine release and attenuates the intensity and frequency of epileptiform activity in hippocampal slices: Evidence for the rapid depletion of cellular ATP during electrographic seizures. J Neurochem 2018; 147:178-189. [PMID: 29964329 PMCID: PMC6220757 DOI: 10.1111/jnc.14543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/05/2018] [Accepted: 06/28/2018] [Indexed: 12/25/2022]
Abstract
In addition to being the universal cellular energy source, ATP is the primary reservoir for the neuromodulator adenosine. Consequently, adenosine is produced during ATP-depleting conditions, such as epileptic seizures, during which adenosine acts as an anticonvulsant to terminate seizure activity and raise the threshold for subsequent seizures. These actions protect neurones from excessive ionic fluxes and hence preserve the remaining cellular content of ATP. We have investigated the consequences of manipulation of intracellular ATP levels on adenosine release and epileptiform activity in hippocampal slices by pre-incubating slices (3 h) with creatine (1 mM) and the combination of ribose (1 mM) and adenine (50 μM; RibAde). Creatine buffers and protects the concentration of cellular ATP, whereas RibAde restores the reduced cellular ATP in brain slices to near physiological levels. Using electrophysiological recordings and microelectrode biosensors for adenosine, we find that, while having no effect on basal synaptic transmission or paired-pulse facilitation, pre-incubation with creatine reduced adenosine release during Mg2+- free/4-aminopyridine-induced electrographic seizure activity, whereas RibAde increased adenosine release. This increased release of adenosine was associated with an attenuation of both the intensity and frequency of seizure activity. Given the depletion of ATP after injury to the brain, the propensity for seizures after trauma and the risk of epileptogenesis, therapeutic strategies elevating the cellular reservoir of adenosine may have value in the traumatized brain. Ribose and adenine are both in use in man and thus their combination merits consideration as a potential therapeutic for the acutely injured central nervous system.
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Affiliation(s)
- Jessicka Hall
- School of Life SciencesThe University of WarwickCoventryUK
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17
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Reinhart KM, Shuttleworth CW. Ketamine reduces deleterious consequences of spreading depolarizations. Exp Neurol 2018; 305:121-128. [PMID: 29653188 PMCID: PMC6261532 DOI: 10.1016/j.expneurol.2018.04.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/31/2018] [Accepted: 04/08/2018] [Indexed: 01/12/2023]
Abstract
Recent work has implicated spreading depolarization (SD) as a key contributor the progression of acute brain injuries, however development of interventions selectively targeting SD has lagged behind. Initial clinical intervention efforts have focused on observations that relatively high doses of the sedative agent ketamine can completely suppress SD. However, blocking propagation of SD could theoretically prevent beneficial effects of SD in surrounding brain regions. Selective targeting of deleterious consequences of SD (rather than abolition) could be a useful adjunct approach, and be achieved with lower ketamine concentrations. We utilized a brain slice model to test whether deleterious consequences of SD could be prevented by ketamine, using concentrations that did not prevent the initiation and propagation of SD. Studies were conducted using murine brain slices, with focal KCl as an SD stimulus. Consequences of SD were assessed with electrophysiological and imaging measures of ionic and synaptic recovery. Under control conditions, ketamine (up to 30 μM) did not prevent SD, but significantly reduced neuronal Ca2+ loading and the duration of associated extracellular potential shifts. Recovery of postsynaptic potentials after SD was also significantly accelerated. When SD was evoked on a background of mild metabolic compromise, neuronal recovery was substantially impaired. Under compromised conditions, the same concentrations of ketamine reduced ionic and metabolic loading during SD, sufficient to preserve functional recovery after repetitive SDs. These results suggest that lower concentrations of ketamine could be utilized to prevent damaging consequences of SD, while not blocking them outright and thereby preserving potentially protective effects of SD.
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Affiliation(s)
- Katelyn M Reinhart
- Department of Neurosciences, University of New Mexico School of Medicine, United States
| | - C William Shuttleworth
- Department of Neurosciences, University of New Mexico School of Medicine, United States.
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Mahoney DE, Hiebert JB, Thimmesch A, Pierce JT, Vacek JL, Clancy RL, Sauer AJ, Pierce JD. Understanding D-Ribose and Mitochondrial Function. ACTA ACUST UNITED AC 2018; 6:1-5. [PMID: 29780691 PMCID: PMC5959283 DOI: 10.7575/aiac.abcmed.v.6n.1p.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mitochondria are important organelles referred to as cellular powerhouses for their unique properties of cellular energy production. With many pathologic conditions and aging, mitochondrial function declines, and there is a reduction in the production of adenosine triphosphate. The energy carrying molecule generated by cellular respiration and by pentose phosphate pathway, an alternative pathway of glucose metabolism. D-ribose is a naturally occurring monosaccharide found in the cells and particularly in the mitochondria is essential in energy production. Without sufficient energy, cells cannot maintain integrity and function. Supplemental D-ribose has been shown to improve cellular processes when there is mitochondrial dysfunction. When individuals take supplemental D-ribose, it can bypass part of the pentose pathway to produce D-ribose-5-phosphate for the production of energy. In this article, we review how energy is produced by cellular respiration, the pentose pathway, and the use of supplemental D-ribose.
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Affiliation(s)
- Diane E Mahoney
- University of Kansas Medical Center, School of Nursing, Kansas, US
| | - John B Hiebert
- University of Kansas Medical Center, School of Nursing, Kansas, US
| | - Amanda Thimmesch
- University of Kansas Medical Center, School of Nursing, Kansas, US
| | - John T Pierce
- University of Kansas Medical Center, School of Nursing, Kansas, US
| | | | - Richard L Clancy
- University of Kansas Medical Center, School of Nursing, Kansas, US
| | - Andrew J Sauer
- Center for Advanced Heart Failure and Heart Transplantation, Kansas, US
| | - Janet D Pierce
- University of Kansas Medical Center, School of Nursing, Kansas, US
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