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Groth B, Venkatakrishnan P, Lin SJ. NAD + Metabolism, Metabolic Stress, and Infection. Front Mol Biosci 2021; 8:686412. [PMID: 34095234 PMCID: PMC8171187 DOI: 10.3389/fmolb.2021.686412] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/05/2021] [Indexed: 12/26/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite with wide-ranging and significant roles in the cell. Defects in NAD+ metabolism have been associated with many human disorders; it is therefore an emerging therapeutic target. Moreover, NAD+ metabolism is perturbed during colonization by a variety of pathogens, either due to the molecular mechanisms employed by these infectious agents or by the host immune response they trigger. Three main biosynthetic pathways, including the de novo and salvage pathways, contribute to the production of NAD+ with a high degree of conservation from bacteria to humans. De novo biosynthesis, which begins with l-tryptophan in eukaryotes, is also known as the kynurenine pathway. Intermediates of this pathway have various beneficial and deleterious effects on cellular health in different contexts. For example, dysregulation of this pathway is linked to neurotoxicity and oxidative stress. Activation of the de novo pathway is also implicated in various infections and inflammatory signaling. Given the dynamic flexibility and multiple roles of NAD+ intermediates, it is important to understand the interconnections and cross-regulations of NAD+ precursors and associated signaling pathways to understand how cells regulate NAD+ homeostasis in response to various growth conditions. Although regulation of NAD+ homeostasis remains incompletely understood, studies in the genetically tractable budding yeast Saccharomyces cerevisiae may help provide some molecular basis for how NAD+ homeostasis factors contribute to the maintenance and regulation of cellular function and how they are regulated by various nutritional and stress signals. Here we present a brief overview of recent insights and discoveries made with respect to the relationship between NAD+ metabolism and selected human disorders and infections, with a particular focus on the de novo pathway. We also discuss how studies in budding yeast may help elucidate the regulation of NAD+ homeostasis.
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Affiliation(s)
- Benjamin Groth
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, United States
| | - Padmaja Venkatakrishnan
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, United States
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, United States
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Iron activates microglia and directly stimulates indoleamine-2,3-dioxygenase activity in the N171-82Q mouse model of Huntington's disease. PLoS One 2021; 16:e0250606. [PMID: 33989290 PMCID: PMC8121302 DOI: 10.1371/journal.pone.0250606] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/10/2021] [Indexed: 01/05/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a dominant CAG-repeat expansion in the huntingtin gene. Microglial activation is a key feature of HD pathology, and is present before clinical disease onset. The kynurenine pathway (KP) of tryptophan degradation is activated in HD, and is thought to contribute to disease progression. Indoleamine-2,3-dioxygenase (IDO) catalyzes the first step in this pathway; this and other pathway enzymes reside with microglia. While HD brain microglia accumulate iron, the role of iron in promoting microglial activation and KP activity is unclear. Here we utilized the neonatal iron supplementation model to investigate the relationship between iron, microglial activation and neurodegeneration in adult HD mice. We show in the N171-82Q mouse model of HD microglial morphologic changes consistent with immune activation. Neonatal iron supplementation in these mice promoted neurodegeneration and resulted in additional microglial activation in adults as determined by increased soma volume and decreased process length. We further demonstrate that iron activates IDO, both in brain lysates and purified recombinant protein (EC50 = 1.24 nM). Brain IDO activity is increased by HD. Neonatal iron supplementation further promoted IDO activity in cerebral cortex, altered KP metabolite profiles, and promoted HD neurodegeneration as measured by brain weights and striatal volumes. Our results demonstrate that dietary iron is an important activator of microglia and the KP pathway in this HD model, and that this occurs in part through a direct effect on IDO. The findings are relevant to understanding how iron promotes neurodegeneration in HD.
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Venkatesan D, Iyer M, Narayanasamy A, Siva K, Vellingiri B. Kynurenine pathway in Parkinson's disease-An update. eNeurologicalSci 2020; 21:100270. [PMID: 33134567 PMCID: PMC7585940 DOI: 10.1016/j.ensci.2020.100270] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/05/2020] [Accepted: 08/26/2020] [Indexed: 12/24/2022] Open
Abstract
Parkinson's disease (PD) is a complex multi-factorial neurodegenerative disorder where various altered metabolic pathways contribute to the progression of the disease. Tryptophan (TRP) is a major precursor in kynurenine pathway (KP) and it has been discussed in various in vitro studies that the metabolites quinolinic acid (QUIN) causes neurotoxicity and kynurenic acid (KYNA) acts as neuroprotectant respectively. More studies are also focused on the effects of other KP metabolites and its enzymes as it has an association with ageing and PD pathogenesis. Until now, very few studies have targeted the role of genetic mutations in abnormal KP metabolism in adverse conditions of PD. Therefore, the present review gives an updated research studies on KP in connection with PD. Moreover, the review emphasizes on the urge for the development of biomarkers and also this would be an initiative in generating an alternative therapeutic approach for PD.
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Key Words
- 3-HAA, 3-hydroxyanthranilic acid
- 3-HK, 3-hydroxykynurenine
- 6-OHDA, 6-hydroxydopamine
- AA, anthranilic acid
- ACMSD, amino-carboxymuconatesemialdehyde decarboxylase
- AD, Alzheimer's disease
- ATP, adenosine triphosphate
- Ageing
- AhR, aryl hydrocarbon receptor
- Biomarkers
- CNS, central nervous system
- CSF, cerebrospinal fluid
- DA, dopaminergic
- FAM, formamidase
- IDO-1, indoleamine-2,3-dioxygenases
- IFN-γ, interferon-γ
- KATs, kynurenine aminotransferases
- KMO, kynurenine −3-monooxygenase
- KP, Kynurenine pathway
- KYN, kynurenine
- KYNA, kynurenic acid
- Kynurenine pathway (KP)
- L-DOPA, L-dopamine
- LID, L-DOPA-induced dyskinesia
- MPTP, 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine
- NAD+, nicotinamide adenine dinucleotide
- NADPH, nicotinamide adenine dinucleotide phosphate
- NFK, N′-formylkynurenine
- NMDA, N-methyl-d-aspartate
- PA, picolinic acid
- PD, Parkinson's disease
- Parkinson's disease (PD)
- QUIN, quinolinic acid
- RBCs, red blood cells
- SNpc, substantianigra pars compacta
- TDO, tryptophan 2,3-dioxygenase
- TRP, tryptophan
- Therapeutics
- XA, xanthurenic acid
- ZNS, zonisamide
- α-synuclein, αSyn
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Affiliation(s)
- Dhivya Venkatesan
- Human Molecular Cytogenetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India
| | - Mahalaxmi Iyer
- Department of Zoology, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore 641 043, Tamil Nadu, India
| | - Arul Narayanasamy
- Disease Proteomics Laboratory, Department of Zoology, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India
| | - Kamalakannan Siva
- National Centre for Disease Control, Ministry of Health and Family Welfare, Government of India, New Delhi 110054, India
| | - Balachandar Vellingiri
- Human Molecular Cytogenetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India
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Hansra GK, Popov G, Banaczek PO, Vogiatzis M, Jegathees T, Goldsbury CS, Cullen KM. The neuritic plaque in Alzheimer's disease: perivascular degeneration of neuronal processes. Neurobiol Aging 2019; 82:88-101. [PMID: 31437721 DOI: 10.1016/j.neurobiolaging.2019.06.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 12/14/2022]
Abstract
Cerebrovascular pathology is common in aging and Alzheimer's disease (AD). The microvasculature is particularly vulnerable, with capillary-level microhemorrhages coinciding with amyloid beta deposits in senile plaques. In the current analysis, we assessed the relationship between cerebral microvessels and the neuritic component of the plaque in cortical and hippocampal 50- to 200-μm sections from 11 AD, 3 Down syndrome, and 7 nondemented cases in neuritic disease stages 0-VI. We report that 77%-97% of neuritic plaques are perivascular, independently of disease stage or dementia diagnosis. Within neuritic plaques, dystrophic hyperphosphorylated tau-positive neurites appear as clusters of punctate, bulbous, and thread-like structures focused around capillaries and colocalize with iron deposits characteristic of microhemorrhage. Microvessels within the neuritic plaque are narrowed by 1.0 ± 1.0 μm-4.4 ± 2.0 μm, a difference of 16%-65% compared to blood vessel segments with diameters 7.9 ± 2.0-6.4 ± 0.8 μm (p < 0.01) outside the plaque domain. The reduced capacity of microvessels within plaques, frequently below patency, likely compromises normal microlocal cerebrovascular perfusion. These data link the neuritic and amyloid beta components of the plaque directly to microvascular degeneration. Strategies focused on cerebrovascular antecedents to neuritic dystrophy in AD have immediate potential for prevention, detection, and therapeutic intervention.
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Affiliation(s)
- Gurpreet Kaur Hansra
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Glib Popov
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Patricia O Banaczek
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Monica Vogiatzis
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Thuvarahan Jegathees
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Claire S Goldsbury
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; Brain and Mind Centre, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Karen M Cullen
- Discipline of Anatomy & Histology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia.
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Badawy AAB. Kynurenine Pathway of Tryptophan Metabolism: Regulatory and Functional Aspects. Int J Tryptophan Res 2017; 10:1178646917691938. [PMID: 28469468 PMCID: PMC5398323 DOI: 10.1177/1178646917691938] [Citation(s) in RCA: 618] [Impact Index Per Article: 88.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/11/2017] [Indexed: 12/21/2022] Open
Abstract
Regulatory and functional aspects of the kynurenine (K) pathway (KP) of tryptophan (Trp) degradation are reviewed. The KP accounts for ~95% of dietary Trp degradation, of which 90% is attributed to the hepatic KP. During immune activation, the minor extrahepatic KP plays a more active role. The KP is rate-limited by its first enzyme, Trp 2,3-dioxygenase (TDO), in liver and indoleamine 2,3-dioxygenase (IDO) elsewhere. TDO is regulated by glucocorticoid induction, substrate activation and stabilization by Trp, cofactor activation by heme, and end-product inhibition by reduced nicotinamide adenine dinucleotide (phosphate). IDO is regulated by IFN-γ and other cytokines and by nitric oxide. The KP disposes of excess Trp, controls hepatic heme synthesis and Trp availability for cerebral serotonin synthesis, and produces immunoregulatory and neuroactive metabolites, the B3 “vitamin” nicotinic acid, and oxidized nicotinamide adenine dinucleotide. Various KP enzymes are undermined in disease and are targeted for therapy of conditions ranging from immunological, neurological, and neurodegenerative conditions to cancer.
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Affiliation(s)
- Abdulla A-B Badawy
- Cardiff School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
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Lee JM, Tan V, Lovejoy D, Braidy N, Rowe DB, Brew BJ, Guillemin GJ. Involvement of quinolinic acid in the neuropathogenesis of amyotrophic lateral sclerosis. Neuropharmacology 2017; 112:346-364. [DOI: 10.1016/j.neuropharm.2016.05.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/13/2016] [Accepted: 05/17/2016] [Indexed: 10/21/2022]
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Muller M, Leavitt BR. Iron dysregulation in Huntington's disease. J Neurochem 2014; 130:328-50. [PMID: 24717009 DOI: 10.1111/jnc.12739] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/19/2014] [Accepted: 04/07/2014] [Indexed: 12/13/2022]
Abstract
Huntington's disease (HD) is one of many neurodegenerative diseases with reported alterations in brain iron homeostasis that may contribute to neuropathogenesis. Iron accumulation in the specific brain areas of neurodegeneration in HD has been proposed based on observations in post-mortem tissue and magnetic resonance imaging studies. Altered magnetic resonance imaging signal within specific brain regions undergoing neurodegeneration has been consistently reported and interpreted as altered levels of brain iron. Biochemical studies using various techniques to measure iron species in human samples, mouse tissue, or in vitro has generated equivocal data to support such an association. Whether elevated brain iron occurs in HD, plays a significant contributing role in HD pathogenesis, or is a secondary effect remains currently unclear.
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Affiliation(s)
- Michelle Muller
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, University of British Columbia and Children's and Women's Hospital, Vancouver, British Columbia, Canada
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Reyes Ocampo J, Lugo Huitrón R, González-Esquivel D, Ugalde-Muñiz P, Jiménez-Anguiano A, Pineda B, Pedraza-Chaverri J, Ríos C, Pérez de la Cruz V. Kynurenines with neuroactive and redox properties: relevance to aging and brain diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:646909. [PMID: 24693337 PMCID: PMC3945746 DOI: 10.1155/2014/646909] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/12/2013] [Accepted: 12/15/2013] [Indexed: 11/18/2022]
Abstract
The kynurenine pathway (KP) is the main route of tryptophan degradation whose final product is NAD(+). The metabolism of tryptophan can be altered in ageing and with neurodegenerative process, leading to decreased biosynthesis of nicotinamide. This fact is very relevant considering that tryptophan is the major source of body stores of the nicotinamide-containing NAD(+) coenzymes, which is involved in almost all the bioenergetic and biosynthetic metabolism. Recently, it has been proposed that endogenous tryptophan and its metabolites can interact and/or produce reactive oxygen species in tissues and cells. This subject is of great importance due to the fact that oxidative stress, alterations in KP metabolites, energetic deficit, cell death, and inflammatory events may converge each other to enter into a feedback cycle where each one depends on the other to exert synergistic actions among them. It is worth mentioning that all these factors have been described in aging and in neurodegenerative processes; however, has so far no one established any direct link between alterations in KP and these factors. In this review, we describe each kynurenine remarking their redox properties, their effects in experimental models, their alterations in the aging process.
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Affiliation(s)
- Jazmin Reyes Ocampo
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., Insurgentes Sur 3877, 14269 México, DF, Mexico
- Área de Neurociencias, Departamento de Biología de la Reproducción, Universidad Autónoma Metropolitana-Iztapalapa, 09340 México, DF, Mexico
| | - Rafael Lugo Huitrón
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., Insurgentes Sur 3877, 14269 México, DF, Mexico
| | - Dinora González-Esquivel
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., Insurgentes Sur 3877, 14269 México, DF, Mexico
| | - Perla Ugalde-Muñiz
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., Insurgentes Sur 3877, 14269 México, DF, Mexico
| | - Anabel Jiménez-Anguiano
- Área de Neurociencias, Departamento de Biología de la Reproducción, Universidad Autónoma Metropolitana-Iztapalapa, 09340 México, DF, Mexico
| | - Benjamín Pineda
- Laboratorio de Neuroinmunología, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., 14269 México, DF, Mexico
| | - José Pedraza-Chaverri
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, 04510 México, DF, Mexico
| | - Camilo Ríos
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., Insurgentes Sur 3877, 14269 México, DF, Mexico
| | - Verónica Pérez de la Cruz
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A., Insurgentes Sur 3877, 14269 México, DF, Mexico
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Quinolinic acid: neurotoxin or oxidative stress modulator? Int J Mol Sci 2013; 14:21328-38. [PMID: 24232578 PMCID: PMC3856007 DOI: 10.3390/ijms141121328] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/02/2013] [Accepted: 10/22/2013] [Indexed: 01/01/2023] Open
Abstract
Quinolinic acid (2,3-pyridinedicarboxylic acid, QUIN) is a well-known neurotoxin. Consequently, QUIN could produce reactive oxygen species (ROS). ROS are generated in reactions catalyzed by transition metals, especially iron (Fe). QUIN can form coordination complexes with iron. A combination of differential pulse voltammetry, deoxyribose degradation and Fe(II) autoxidation assays was used for explorating ROS formation in redox reactions that are catalyzed by iron in QUIN-Fe complexes. Differential pulse voltammetry showed an anodic shift of the iron redox potential if iron was liganded by QUIN. In the H2O2/FeCl3/ascorbic acid variant of the deoxyribose degradation assay, the dose-response curve was U-shaped. In the FeCl3/ascorbic acid variant, QUIN unambiguously showed antioxidant effects. In the Fe(II) autoxidation assay, QUIN decreased the rate of ROS production caused by Fe(II) oxidation. Our study confirms that QUIN toxicity may be caused by ROS generation via the Fenton reaction. This, however, applies only for unnaturally high concentrations that were used in attempts to provide support for the neurotoxic effect. In lower concentrations, we show that by liganding iron, QUIN affects the Fe(II)/Fe(III) ratios that are beneficial to homeostasis. Our results support the notion that redox chemistry can contribute to explaining the hormetic dose-response effects.
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Quinolinic acid: an endogenous neurotoxin with multiple targets. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:104024. [PMID: 24089628 PMCID: PMC3780648 DOI: 10.1155/2013/104024] [Citation(s) in RCA: 400] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/23/2013] [Accepted: 08/01/2013] [Indexed: 11/21/2022]
Abstract
Quinolinic acid (QUIN), a neuroactive metabolite of the kynurenine pathway, is normally presented in nanomolar concentrations in human brain and cerebrospinal fluid (CSF) and is often implicated in the pathogenesis of a variety of human neurological diseases. QUIN is an agonist of N-methyl-D-aspartate (NMDA) receptor, and it has a high in vivo potency as an excitotoxin. In fact, although QUIN has an uptake system, its neuronal degradation enzyme is rapidly saturated, and the rest of extracellular QUIN can continue stimulating the NMDA receptor. However, its toxicity cannot be fully explained by its activation of NMDA receptors it is likely that additional mechanisms may also be involved. In this review we describe some of the most relevant targets of QUIN neurotoxicity which involves presynaptic receptors, energetic dysfunction, oxidative stress, transcription factors, cytoskeletal disruption, behavior alterations, and cell death.
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Colín-González AL, Maldonado PD, Santamaría A. 3-Hydroxykynurenine: an intriguing molecule exerting dual actions in the central nervous system. Neurotoxicology 2012; 34:189-204. [PMID: 23219925 DOI: 10.1016/j.neuro.2012.11.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/23/2012] [Accepted: 11/27/2012] [Indexed: 11/26/2022]
Abstract
Kynurenine pathway is gaining attention due to the many metabolic processes in which it has been involved. The tryptophan conversion into several other metabolites through this pathway provides neuronal and redox modulators useful for maintenance of major functions in the brain. However, when physiopathological conditions prevail - i.e. oxidative stress, excitotoxicity, and inflammation - preferential formation and accumulation of toxic metabolites could trigger factors for degeneration in neurological disorders. 3-Hydroxykynurenine has been largely described as one of these toxic metabolites capable of inducing oxidative damage and cell death; consequently, this metabolite has been hypothesized to play a pivotal role in different neurological and psychiatric disorders. Supporting evidence has shown altered 3-hydroxykynurenine levels in samples of patients from several disorders. In contrast, some experimental studies have provided evidence of antioxidant and scavenging properties inherent to this molecule. In this review, we explored most of literature favoring one or the other concept, in order to provide an accurate vision on the real participation of this tryptophan metabolite in both experimental paradigms and human brain pathologies. Through this collected evidence, we provide an integrative hypothesis on how 3-hydroxykynurenine is exerting its dual actions in the central nervous system and what will be the course of investigations in this field for the next years.
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Affiliation(s)
- Ana Laura Colín-González
- Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía, Insurgentes Sur 3877, Mexico City 14269, Mexico
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Schwarcz R, Bruno JP, Muchowski PJ, Wu HQ. Kynurenines in the mammalian brain: when physiology meets pathology. Nat Rev Neurosci 2012; 13:465-77. [PMID: 22678511 DOI: 10.1038/nrn3257] [Citation(s) in RCA: 1003] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The essential amino acid tryptophan is not only a precursor of serotonin but is also degraded to several other neuroactive compounds, including kynurenic acid, 3-hydroxykynurenine and quinolinic acid. The synthesis of these metabolites is regulated by an enzymatic cascade, known as the kynurenine pathway, that is tightly controlled by the immune system. Dysregulation of this pathway, resulting in hyper-or hypofunction of active metabolites, is associated with neurodegenerative and other neurological disorders, as well as with psychiatric diseases such as depression and schizophrenia. With recently developed pharmacological agents, it is now possible to restore metabolic equilibrium and envisage novel therapeutic interventions.
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Affiliation(s)
- Robert Schwarcz
- University of Maryland School of Medicine, Baltimore, Maryland 21228, USA. rschwarc@mprc. umaryland.edu
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