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Kondo T, Okada Y, Shizuya S, Yamaguchi N, Hatakeyama S, Maruyama K. Neuroimmune modulation by tryptophan derivatives in neurological and inflammatory disorders. Eur J Cell Biol 2024; 103:151418. [PMID: 38729083 DOI: 10.1016/j.ejcb.2024.151418] [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: 12/25/2023] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024] Open
Abstract
The nervous and immune systems are highly developed, and each performs specialized physiological functions. However, they work together, and their dysfunction is associated with various diseases. Specialized molecules, such as neurotransmitters, cytokines, and more general metabolites, are essential for the appropriate regulation of both systems. Tryptophan, an essential amino acid, is converted into functional molecules such as serotonin and kynurenine, both of which play important roles in the nervous and immune systems. The role of kynurenine metabolites in neurodegenerative and psychiatric diseases has recently received particular attention. Recently, we found that hyperactivity of the kynurenine pathway is a critical risk factor for septic shock. In this review, we first outline neuroimmune interactions and tryptophan derivatives and then summarized the changes in tryptophan metabolism in neurological disorders. Finally, we discuss the potential of tryptophan derivatives as therapeutic targets for neuroimmune disorders.
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Affiliation(s)
- Takeshi Kondo
- Department of Biochemistry, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Hokkaido 060-8636, Japan
| | - Yuka Okada
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama 641-0012, Japan
| | - Saika Shizuya
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama 641-0012, Japan
| | - Naoko Yamaguchi
- Department of Pharmacology, School of Medicine, Aichi Medical University, Aichi 480-1195, Japan
| | - Shigetsugu Hatakeyama
- Department of Biochemistry, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Hokkaido 060-8636, Japan
| | - Kenta Maruyama
- Department of Pharmacology, School of Medicine, Aichi Medical University, Aichi 480-1195, Japan.
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Lemieux GA, Yoo S, Lin L, Vohra M, Ashrafi K. The steroid hormone ADIOL promotes learning by reducing neural kynurenic acid levels. Genes Dev 2023; 37:998-1016. [PMID: 38092521 PMCID: PMC10760639 DOI: 10.1101/gad.350745.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 11/22/2023] [Indexed: 12/28/2023]
Abstract
Reductions in brain kynurenic acid levels, a neuroinhibitory metabolite, improve cognitive function in diverse organisms. Thus, modulation of kynurenic acid levels is thought to have therapeutic potential in a range of brain disorders. Here we report that the steroid 5-androstene 3β, 17β-diol (ADIOL) reduces kynurenic acid levels and promotes associative learning in Caenorhabditis elegans We identify the molecular mechanisms through which ADIOL links peripheral metabolic pathways to neural mechanisms of learning capacity. Moreover, we show that in aged animals, which normally experience rapid cognitive decline, ADIOL improves learning capacity. The molecular mechanisms that underlie the biosynthesis of ADIOL as well as those through which it promotes kynurenic acid reduction are conserved in mammals. Thus, rather than a minor intermediate in the production of sex steroids, ADIOL is an endogenous hormone that potently regulates learning capacity by causing reductions in neural kynurenic acid levels.
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Affiliation(s)
- George A Lemieux
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
| | - Shinja Yoo
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
| | - Lin Lin
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
| | - Mihir Vohra
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
| | - Kaveh Ashrafi
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
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Ovalle Rodríguez P, Ramírez Ortega D, Blanco Ayala T, Roldán Roldán G, Pérez de la Cruz G, González Esquivel DF, Gómez-Manzo S, Sánchez Chapul L, Salazar A, Pineda B, Pérez de la Cruz V. Modulation of Kynurenic Acid Production by N-acetylcysteine Prevents Cognitive Impairment in Adulthood Induced by Lead Exposure during Lactation in Mice. Antioxidants (Basel) 2023; 12:2035. [PMID: 38136155 PMCID: PMC10740504 DOI: 10.3390/antiox12122035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
Lead (Pb2+) exposure during early life induces cognitive impairment, which was recently associated with an increase in brain kynurenic acid (KYNA), an antagonist of NMDA and alpha-7 nicotinic receptors. It has been described that N-acetylcysteine (NAC) favors an antioxidant environment and inhibits kynurenine aminotransferase II activity (KAT II, the main enzyme of KYNA production), leading to brain KYNA levels decrease and cognitive improvement. This study aimed to investigate whether the NAC modulation of the brain KYNA levels in mice ameliorated Pb2+-induced cognitive impairment. The dams were divided into four groups: Control, Pb2+, NAC, and Pb2++NAC, which were given drinking water or 500 ppm lead acetate in the drinking water ad libitum, from 0 to 23 postnatal days (PNDs). The NAC and Pb2++NAC groups were simultaneously fed NAC (350 mg/day) in their chow from 0 to 23 PNDs. At PND 60, the effect of the treatment with Pb2+ and in combination with NAC on learning and memory performance was evaluated. Immediately after behavioral evaluation, brain tissues were collected to assess the redox environment; KYNA and glutamate levels; and KAT II activity. The NAC treatment prevented the long-term memory deficit exhibited in the Pb2+ group. As expected, Pb2+ group showed redox environment alterations, fluctuations in glutamate levels, and an increase in KYNA levels, which were partially avoided by NAC co-administration. These results confirmed that the excessive KYNA levels induced by Pb2+ were involved in the onset of cognitive impairment and could be successfully prevented by NAC treatment. NAC could be a tool for testing in scenarios in which KYNA levels are associated with the induction of cognitive impairment.
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Affiliation(s)
- Paulina Ovalle Rodríguez
- Neurochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (P.O.R.); (D.R.O.); (T.B.A.); (D.F.G.E.)
- Posgrado en Ciencias Bioquímicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Unidad de Posgrado, Mexico City 04510, Mexico
| | - Daniela Ramírez Ortega
- Neurochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (P.O.R.); (D.R.O.); (T.B.A.); (D.F.G.E.)
| | - Tonali Blanco Ayala
- Neurochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (P.O.R.); (D.R.O.); (T.B.A.); (D.F.G.E.)
| | - Gabriel Roldán Roldán
- Laboratorio de Neurobiología de la Conducta, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico;
| | - Gonzalo Pérez de la Cruz
- Department of Mathematics, Faculty of Sciences, Universidad Nacional Autónoma de México UNAM, Mexico City 04510, Mexico;
| | - Dinora Fabiola González Esquivel
- Neurochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (P.O.R.); (D.R.O.); (T.B.A.); (D.F.G.E.)
| | - Saúl Gómez-Manzo
- Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, Secretaría de Salud, Mexico City 04530, Mexico;
| | - Laura Sánchez Chapul
- Neuromuscular Diseases Laboratory, Clinical Neurosciences Division, National Institute of Rehabilitation “Luis Guillermo Ibarra Ibarra”, Mexico City 14389, Mexico;
| | - Aleli Salazar
- Neuroimmunology Department, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (A.S.); (B.P.)
| | - Benjamín Pineda
- Neuroimmunology Department, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (A.S.); (B.P.)
| | - Verónica Pérez de la Cruz
- Neurochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (P.O.R.); (D.R.O.); (T.B.A.); (D.F.G.E.)
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Battaglia MR, Di Fazio C, Battaglia S. Activated Tryptophan-Kynurenine metabolic system in the human brain is associated with learned fear. Front Mol Neurosci 2023; 16:1217090. [PMID: 37575966 PMCID: PMC10416643 DOI: 10.3389/fnmol.2023.1217090] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/10/2023] [Indexed: 08/15/2023] Open
Affiliation(s)
- Maria Rita Battaglia
- Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliero-Universitaria di Bologna, Policlinico S. Orsola, Bologna, Italy
| | - Chiara Di Fazio
- Department of Psychology, Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Bologna, Italy
| | - Simone Battaglia
- Department of Psychology, Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Bologna, Italy
- Department of Psychology, University of Turin, Turin, Italy
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Fesharaki Zadeh A, Arnsten AFT, Wang M. Scientific Rationale for the Treatment of Cognitive Deficits from Long COVID. Neurol Int 2023; 15:725-742. [PMID: 37368329 PMCID: PMC10303664 DOI: 10.3390/neurolint15020045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/26/2023] [Accepted: 05/11/2023] [Indexed: 06/28/2023] Open
Abstract
Sustained cognitive deficits are a common and debilitating feature of "long COVID", but currently there are no FDA-approved treatments. The cognitive functions of the dorsolateral prefrontal cortex (dlPFC) are the most consistently afflicted by long COVID, including deficits in working memory, motivation, and executive functioning. COVID-19 infection greatly increases kynurenic acid (KYNA) and glutamate carboxypeptidase II (GCPII) in brain, both of which can be particularly deleterious to PFC function. KYNA blocks both NMDA and nicotinic-alpha-7 receptors, the two receptors required for dlPFC neurotransmission, and GCPII reduces mGluR3 regulation of cAMP-calcium-potassium channel signaling, which weakens dlPFC network connectivity and reduces dlPFC neuronal firing. Two agents approved for other indications may be helpful in restoring dlPFC physiology: the antioxidant N-acetyl cysteine inhibits the production of KYNA, and the α2A-adrenoceptor agonist guanfacine regulates cAMP-calcium-potassium channel signaling in dlPFC and is also anti-inflammatory. Thus, these agents may be helpful in treating the cognitive symptoms of long COVID.
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Affiliation(s)
- Arman Fesharaki Zadeh
- Departments of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Departments of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Amy F. T. Arnsten
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA;
| | - Min Wang
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA;
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Fontana IC, Kumar A, Nordberg A. The role of astrocytic α7 nicotinic acetylcholine receptors in Alzheimer disease. Nat Rev Neurol 2023; 19:278-288. [PMID: 36977843 DOI: 10.1038/s41582-023-00792-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 03/30/2023]
Abstract
The ongoing search for therapeutic interventions in Alzheimer disease (AD) has highlighted the complexity of this condition and the need for additional biomarkers, beyond amyloid-β (Aβ) and tau, to improve clinical assessment. Astrocytes are brain cells that control metabolic and redox homeostasis, among other functions, and are emerging as an important focus of AD research owing to their swift response to brain pathology in the initial stages of the disease. Reactive astrogliosis - the morphological, molecular and functional transformation of astrocytes during disease - has been implicated in AD progression, and the definition of new astrocytic biomarkers could help to deepen our understanding of reactive astrogliosis along the AD continuum. As we highlight in this Review, one promising biomarker candidate is the astrocytic α7 nicotinic acetylcholine receptor (α7nAChR), upregulation of which correlates with Aβ pathology in the brain of individuals with AD. We revisit the past two decades of research into astrocytic α7nAChRs to shed light on their roles in the context of AD pathology and biomarkers. We discuss the involvement of astrocytic α7nAChRs in the instigation and potentiation of early Aβ pathology and explore their potential as a target for future reactive astrocyte-based therapeutics and imaging biomarkers in AD.
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Affiliation(s)
- Igor C Fontana
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Amit Kumar
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
- Theme Inflammation and Aging, Karolinska University Hospital, Stockholm, Sweden.
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Bruno JP. Enhancing the resolution of behavioral measures: Key observations during a forty year career in behavioral neuroscience. Neurosci Biobehav Rev 2023; 145:105004. [PMID: 36549379 DOI: 10.1016/j.neubiorev.2022.105004] [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: 10/16/2022] [Revised: 12/04/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
This manuscript reviews several key observations from the research program of Professor John P. Bruno that are believed to have significantly advanced our understanding of the brain's mediation of behavior. This review focuses on findings within several important research areas in behavioral neuroscience, including a) age-dependent neurobehavioral plasticity following brain damage; b) the role of the cortical cholinergic system in attentional processing and cognitive flexibility; and c) the design and validation of animal models of cognitive deficits in schizophrenia. In selecting these observations, emphasis was given to examples in which the heuristic potency was increased by maximizing the resolution and microanalysis of behavioral assays in the same fashion as one typically refines neuronal manipulations. Professor Bruno served the International Behavioral Neuroscience Society (IBNS) as an IBNS Fellow (1995-present) and President of the IBNS (2001-02).
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Affiliation(s)
- John P Bruno
- Department of Psychology, The Ohio State University, Columbus, OH 43210, USA.
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Kavyani B, Lidbury BA, Schloeffel R, Fisher PR, Missailidis D, Annesley SJ, Dehhaghi M, Heng B, Guillemin GJ. Could the kynurenine pathway be the key missing piece of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) complex puzzle? Cell Mol Life Sci 2022; 79:412. [PMID: 35821534 PMCID: PMC9276562 DOI: 10.1007/s00018-022-04380-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/05/2022] [Accepted: 05/14/2022] [Indexed: 11/03/2022]
Abstract
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex and debilitating disease with a substantial social and economic impact on individuals and their community. Despite its importance and deteriorating impact, progresses in diagnosis and treatment of ME/CFS is limited. This is due to the unclear pathophysiology of the disease and consequently lack of prognostic biomarkers. To investigate pathophysiology of ME/CFS, several potential pathologic hallmarks have been investigated; however, these studies have failed to report a consistent result. These failures in introducing the underlying reason for ME/CFS have stimulated considering other possible contributing mechanisms such as tryptophan (TRP) metabolism and in particular kynurenine pathway (KP). KP plays a central role in cellular energy production through the production of nicotinamide adenine dinucleotide (NADH). In addition, this pathway has been shown to mediate immune response and neuroinflammation through its metabolites. This review, we will discuss the pathology and management of ME/CFS and provide evidence pertaining KP abnormalities and symptoms that are classic characteristics of ME/CFS. Targeting the KP regulation may provide innovative approaches to the management of ME/CFS.
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Affiliation(s)
- Bahar Kavyani
- Neuroinflammation Group, Department of Biomedical Sciences, Macquarie University, Sydney, Australia
| | - Brett A Lidbury
- The National Centre for Epidemiology and Population Health, RSPH, College of Health and Medicine, The Australian National University, Canberra, ACT, 2601, Australia
| | - Richard Schloeffel
- Neuroinflammation Group, Department of Biomedical Sciences, Macquarie University, Sydney, Australia
- The Grove Health Pymble, Sydney, NSW, Australia
| | - Paul R Fisher
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia
| | - Daniel Missailidis
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia
| | - Sarah J Annesley
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia
| | - Mona Dehhaghi
- Neuroinflammation Group, Department of Biomedical Sciences, Macquarie University, Sydney, Australia
| | - Benjamin Heng
- Neuroinflammation Group, Department of Biomedical Sciences, Macquarie University, Sydney, Australia.
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia.
| | - Gilles J Guillemin
- Neuroinflammation Group, Department of Biomedical Sciences, Macquarie University, Sydney, Australia.
- Pandis.org, Melbourne, Australia.
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Hebbrecht K, Morrens M, Giltay EJ, van Nuijs ALN, Sabbe B, van den Ameele S. The Role of Kynurenines in Cognitive Dysfunction in Bipolar Disorder. Neuropsychobiology 2022; 81:184-191. [PMID: 34883494 DOI: 10.1159/000520152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/07/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Chronic low-grade inflammation is suggested to play a pathophysiological role in bipolar disorder (BD) and its related cognitive dysfunctions. Although kynurenine (KYN) pathway metabolites are key inflammatory mediators, studies investigating the association between KYN metabolism and cognition in BD are scarce. We aimed to explore the relationship between KYN metabolism and cognitive functioning across different mood states in BD. METHODS Sixty-seven patients with BD (35 depressed and 32 [hypo] manic) and 29 healthy controls were included. Cognitive functioning was assessed at 3 time intervals (baseline, 4, and 8 months) assessing processing speed, sustained attention, verbal memory, working memory, and response inhibition. Plasma samples for quantification of 3-hydroxykynurenine, quinolinic acid, and kynurenic acid (KYNA) were concurrently provided. Linear mixed models were used for statistical analysis. RESULTS The manic group showed deficits in all assessed cognitive domains with the exception of verbal memory at all test moments. The bipolar depression group showed deficits in the processing speed at all test moments. Throughout the whole follow-up period, KYNA was significantly lower in both patient groups than in controls. Only in the bipolar depression group, low KYNA was associated with worse global cognitive functioning (B = 0.114, p = 0.02) and slower processing speed in particular (B = 0.139, p = 0.03). CONCLUSION Only in the bipolar depression group, lower KYNA was associated with worse cognitive functioning. Future large-scale longitudinal studies are warranted to confirm the role of KYN metabolites in cognitive impairment in patients with BD and the possible therapeutic implications of this relationship.
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Affiliation(s)
- Kaat Hebbrecht
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Scientific Initiative of Neuropsychiatric and Psychopharmacological Studies (SINAPS), University Psychiatric Centre Duffel, Duffel, Belgium.,Department of Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium
| | - Manuel Morrens
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Scientific Initiative of Neuropsychiatric and Psychopharmacological Studies (SINAPS), University Psychiatric Centre Duffel, Duffel, Belgium
| | - Erik J Giltay
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Department of Psychiatry, Leiden University Medical Center, Leiden, The Netherlands
| | - Alexander L N van Nuijs
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Bernard Sabbe
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium
| | - Seline van den Ameele
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Department of Psychiatry, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
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Brown SJ, Brown AM, Purves-Tyson TD, Huang XF, Shannon Weickert C, Newell KA. Alterations in the kynurenine pathway and excitatory amino acid transporter-2 in depression with and without psychosis: Evidence of a potential astrocyte pathology. J Psychiatr Res 2022; 147:203-211. [PMID: 35063739 DOI: 10.1016/j.jpsychires.2021.12.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/24/2021] [Accepted: 12/18/2021] [Indexed: 11/19/2022]
Abstract
Evidence, largely obtained from peripheral studies, suggests that alterations in the kynurenine pathway contribute to the aetiology of depression and disorders involving psychosis. Stimulation of the kynurenine pathway leads to the formation of neuroactive metabolites, including kynurenic acid (predominantly in astrocytes) and quinolinic acid (predominantly in microglia), which are antagonists and agonists of the glutamate NMDA receptor, respectively. In this study, we measured gene expression via qRT-PCR of the main kynurenine pathway enzymes in the anterior cingulate cortex (ACC) in people with major depressive disorder and matched controls. In parallel, we tested for diagnostic differences in gene expression of relevant glial markers. We used total RNA isolated from the ACC from depression subjects with psychosis (n = 12) and without psychosis (n = 12), and non-psychiatric controls (n = 12) provided by the Stanley Medical Research Institute. In the ACC, KYAT1 (KAT I), AADAT (KAT II), and the astrocytic SLC1A2 (EAAT2) mRNAs, were significantly increased in depression, when combining those with and without psychosis. The increased KYAT1 and AADAT mRNA indicates that depression is associated with increased activation of the kynurenic acid arm of the kynurenine pathway in the ACC, suggesting an astrocyte response in depression. Considering EAAT2 and KATs increase astrocytic glutamate uptake and production of the NMDA receptor antagonist kynurenic acid, the observed increases of these markers may relate to changes in glutamatergic signalling in depression. These results suggest dysfunction of the kynurenine pathway in the brain in depression and point to the kynurenine pathway as a possible driver of glutamate dysfunction in depression.
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Affiliation(s)
- Samara J Brown
- School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, New South Wales, 2522, Australia
| | - Amelia M Brown
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, New South Wales, 2031, Australia
| | - Tertia D Purves-Tyson
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, New South Wales, 2031, Australia; School of Psychiatry, Faculty of Medicine, University of New South Wales, Randwick, New South Wales, 2031, Australia
| | - Xu-Feng Huang
- School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, New South Wales, 2522, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, New South Wales, 2031, Australia; School of Psychiatry, Faculty of Medicine, University of New South Wales, Randwick, New South Wales, 2031, Australia; Department of Neuroscience & Physiology, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Kelly A Newell
- School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, New South Wales, 2522, Australia.
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11
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Sathyasaikumar KV, Pérez de la Cruz V, Pineda B, Vázquez Cervantes GI, Ramírez Ortega D, Donley DW, Severson PL, West BL, Giorgini F, Fox JH, Schwarcz R. Cellular Localization of Kynurenine 3-Monooxygenase in the Brain: Challenging the Dogma. Antioxidants (Basel) 2022; 11:antiox11020315. [PMID: 35204197 PMCID: PMC8868204 DOI: 10.3390/antiox11020315] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 02/07/2023] Open
Abstract
Kynurenine 3-monooxygenase (KMO), a key player in the kynurenine pathway (KP) of tryptophan degradation, regulates the synthesis of the neuroactive metabolites 3-hydroxykynurenine (3-HK) and kynurenic acid (KYNA). KMO activity has been implicated in several major brain diseases including Huntington’s disease (HD) and schizophrenia. In the brain, KMO is widely believed to be predominantly localized in microglial cells, but verification in vivo has not been provided so far. Here, we examined KP metabolism in the brain after depleting microglial cells pharmacologically with the colony stimulating factor 1 receptor inhibitor PLX5622. Young adult mice were fed PLX5622 for 21 days and were euthanized either on the next day or after receiving normal chow for an additional 21 days. Expression of microglial marker genes was dramatically reduced on day 22 but had fully recovered by day 43. In both groups, PLX5622 treatment failed to affect Kmo expression, KMO activity or tissue levels of 3-HK and KYNA in the brain. In a parallel experiment, PLX5622 treatment also did not reduce KMO activity, 3-HK and KYNA in the brain of R6/2 mice (a model of HD with activated microglia). Finally, using freshly isolated mouse cells ex vivo, we found KMO only in microglia and neurons but not in astrocytes. Taken together, these data unexpectedly revealed that neurons contain a large proportion of functional KMO in the adult mouse brain under both physiological and pathological conditions.
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Affiliation(s)
- Korrapati V. Sathyasaikumar
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA;
| | - Verónica Pérez de la Cruz
- Neurobiochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (V.P.d.l.C.); (G.I.V.C.); (D.R.O.)
| | - Benjamín Pineda
- Neuroimmunology Department, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico;
| | - Gustavo Ignacio Vázquez Cervantes
- Neurobiochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (V.P.d.l.C.); (G.I.V.C.); (D.R.O.)
| | - Daniela Ramírez Ortega
- Neurobiochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (V.P.d.l.C.); (G.I.V.C.); (D.R.O.)
| | - David W. Donley
- Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82071, USA; (D.W.D.); (J.H.F.)
| | - Paul L. Severson
- Plexxikon Inc., South San Francisco, CA 94080, USA; (P.L.S.); (B.L.W.)
| | - Brian L. West
- Plexxikon Inc., South San Francisco, CA 94080, USA; (P.L.S.); (B.L.W.)
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7JA, UK;
| | - Jonathan H. Fox
- Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82071, USA; (D.W.D.); (J.H.F.)
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA;
- Correspondence: ; Tel.: +1-410-402-7635
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12
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Abstract
Uremic encephalopathy encompasses a wide range of central nervous system abnormalities associated with poor kidney function occurring with either progressive chronic kidney disease or acute kidney injury. The syndrome is likely caused by retention of uremic solutes, alterations in hormonal metabolism, changes in electrolyte and acid-base homeostasis, as well as changes in vascular reactivity, blood-brain barrier transport, and inflammation. There are no defining clinical, laboratory, or imaging findings, and the diagnosis is often made retrospectively when symptoms improve after dialysis or transplantation. The diagnosis is also made difficult because of the many confounding and overlapping conditions seen in patients with chronic kidney disease and acute kidney injury. Thus, institution of kidney replacement therapy should be considered as a trial to improve symptoms in the right clinical context. Neurological symptoms that do not improve after improvement in clearance should prompt a search for other explanations. Further knowledge linking possible uremic retention solutes with neurological symptoms is needed to better understand this syndrome as well as to develop more tailored treatments that aim to improve cognitive function.
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Marszalek-Grabska M, Walczak K, Gawel K, Wicha-Komsta K, Wnorowska S, Wnorowski A, Turski WA. Kynurenine emerges from the shadows – Current knowledge on its fate and function. Pharmacol Ther 2021; 225:107845. [DOI: 10.1016/j.pharmthera.2021.107845] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022]
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Bai MY, Lovejoy DB, Guillemin GJ, Kozak R, Stone TW, Koola MM. Galantamine-Memantine Combination and Kynurenine Pathway Enzyme Inhibitors in the Treatment of Neuropsychiatric Disorders. Complex Psychiatry 2021; 7:19-33. [PMID: 35141700 PMCID: PMC8443947 DOI: 10.1159/000515066] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/04/2021] [Indexed: 12/25/2022] Open
Abstract
The kynurenine pathway (KP) is a major route for L-tryptophan (L-TRP) metabolism, yielding a variety of bioactive compounds including kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), quinolinic acid (QUIN), and picolinic acid (PIC). These tryptophan catabolites are involved in the pathogenesis of many neuropsychiatric disorders, particularly when the KP becomes dysregulated. Accordingly, the enzymes that regulate the KP such as indoleamine 2,3-dioxygenase (IDO)/tryptophan 2,3-dioxygenase, kynurenine aminotransferases (KATs), and kynurenine 3-monooxygenase (KMO) represent potential drug targets as enzymatic inhibition can favorably rebalance KP metabolite concentrations. In addition, the galantamine-memantine combination, through its modulatory effects at the alpha7 nicotinic acetylcholine receptors and N-methyl-D-aspartate receptors, may counteract the effects of KYNA. The aim of this review is to highlight the effectiveness of IDO-1, KAT II, and KMO inhibitors, as well as the galantamine-memantine combination in the modulation of different KP metabolites. KAT II inhibitors are capable of decreasing the KYNA levels in the rat brain by a maximum of 80%. KMO inhibitors effectively reduce the central nervous system (CNS) levels of 3-HK, while markedly boosting the brain concentration of KYNA. Emerging data suggest that the galantamine-memantine combination also lowers L-TRP, kynurenine, KYNA, and PIC levels in humans. Presently, there are only 2 pathophysiological mechanisms (cholinergic and glutamatergic) that are FDA approved for the treatment of cognitive dysfunction for which purpose the galantamine-memantine combination has been designed for clinical use against Alzheimer's disease. The alpha7 nicotinic-NMDA hypothesis targeted by the galantamine-memantine combination has been implicated in the pathophysiology of various CNS diseases. Similarly, KYNA is well capable of modulating the neuropathophysiology of these disorders. This is known as the KYNA-centric hypothesis, which may be implicated in the management of certain neuropsychiatric conditions. In line with this hypothesis, KYNA may be considered as the "conductor of the orchestra" for the major pathophysiological mechanisms underlying CNS disorders. Therefore, there is great opportunity to further explore and compare the biological effects of these therapeutic modalities in animal models with a special focus on their effects on KP metabolites in the CNS and with the ultimate goal of progressing to clinical trials for many neuropsychiatric diseases.
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Affiliation(s)
- Michael Y. Bai
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David B. Lovejoy
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Gilles J. Guillemin
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Rouba Kozak
- Neuroscience Drug Discovery Unit, Takeda Pharmaceuticals International Co, Cambridge, Massachusetts, USA
| | - Trevor W. Stone
- Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Maju Mathew Koola
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, Stony Brook, New York, USA
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15
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Mithaiwala MN, Santana-Coelho D, Porter GA, O’Connor JC. Neuroinflammation and the Kynurenine Pathway in CNS Disease: Molecular Mechanisms and Therapeutic Implications. Cells 2021; 10:1548. [PMID: 34205235 PMCID: PMC8235708 DOI: 10.3390/cells10061548] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/13/2021] [Accepted: 06/15/2021] [Indexed: 12/16/2022] Open
Abstract
Diseases of the central nervous system (CNS) remain a significant health, social and economic problem around the globe. The development of therapeutic strategies for CNS conditions has suffered due to a poor understanding of the underlying pathologies that manifest them. Understanding common etiological origins at the cellular and molecular level is essential to enhance the development of efficacious and targeted treatment options. Over the years, neuroinflammation has been posited as a common link between multiple neurological, neurodegenerative and neuropsychiatric disorders. Processes that precipitate neuroinflammatory conditions including genetics, infections, physical injury and psychosocial factors, like stress and trauma, closely link dysregulation in kynurenine pathway (KP) of tryptophan metabolism as a possible pathophysiological factor that 'fuel the fire' in CNS diseases. In this study, we aim to review emerging evidence that provide mechanistic insights between different CNS disorders, neuroinflammation and the KP. We provide a thorough overview of the different branches of the KP pertinent to CNS disease pathology that have therapeutic implications for the development of selected and efficacious treatment strategies.
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Affiliation(s)
- Mustafa N. Mithaiwala
- Integrated Biomedical Sciences Program, Graduate School of Biomedical Sciences, UT Health San Antonio, San Antonio, TX 78229, USA; (M.N.M.); (D.S.-C.); (G.A.P.)
- Department of Pharmacology, Long School of Medicine, UT Health San Antonio, Mail Code 8864, San Antonio, TX 78229, USA
| | - Danielle Santana-Coelho
- Integrated Biomedical Sciences Program, Graduate School of Biomedical Sciences, UT Health San Antonio, San Antonio, TX 78229, USA; (M.N.M.); (D.S.-C.); (G.A.P.)
- Department of Pharmacology, Long School of Medicine, UT Health San Antonio, Mail Code 8864, San Antonio, TX 78229, USA
| | - Grace A. Porter
- Integrated Biomedical Sciences Program, Graduate School of Biomedical Sciences, UT Health San Antonio, San Antonio, TX 78229, USA; (M.N.M.); (D.S.-C.); (G.A.P.)
- Department of Pharmacology, Long School of Medicine, UT Health San Antonio, Mail Code 8864, San Antonio, TX 78229, USA
| | - Jason C. O’Connor
- Integrated Biomedical Sciences Program, Graduate School of Biomedical Sciences, UT Health San Antonio, San Antonio, TX 78229, USA; (M.N.M.); (D.S.-C.); (G.A.P.)
- Department of Pharmacology, Long School of Medicine, UT Health San Antonio, Mail Code 8864, San Antonio, TX 78229, USA
- Department of Research, Audie L. Murphy VA Hospital, South Texas Veterans Heath System, San Antonio, TX 78229, USA
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16
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Collier ME, Zhang S, Scrutton NS, Giorgini F. Inflammation control and improvement of cognitive function in COVID-19 infections: is there a role for kynurenine 3-monooxygenase inhibition? Drug Discov Today 2021; 26:1473-1481. [PMID: 33609782 PMCID: PMC7889466 DOI: 10.1016/j.drudis.2021.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/26/2021] [Accepted: 02/10/2021] [Indexed: 02/07/2023]
Abstract
The novel respiratory virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), emerged during late 2019 and spread rapidly across the world. It is now recognised that the nervous system can be affected in COVID-19, with several studies reporting long-term cognitive problems in patients. The metabolic pathway of tryptophan degradation, known as the kynurenine pathway (KP), is significantly activated in patients with COVID-19. KP metabolites have roles in regulating both inflammatory/immune responses and neurological functions. In this review, we speculate on the effects of KP activation in patients with COVID-19, and how modulation of this pathway might impact inflammation and reduce neurological symptoms.
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Affiliation(s)
- Mary Ew Collier
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK.
| | - Shaowei Zhang
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
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17
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Wickström R, Fowler Å, Goiny M, Millischer V, Ygberg S, Schwieler L. The Kynurenine Pathway is Differentially Activated in Children with Lyme Disease and Tick-Borne Encephalitis. Microorganisms 2021; 9:microorganisms9020322. [PMID: 33557172 PMCID: PMC7913947 DOI: 10.3390/microorganisms9020322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 01/03/2023] Open
Abstract
In children, tick-borne encephalitis and neuroborreliosis are common infections affecting the central nervous system. As inflammatory pathways including cytokine expression are activated in these children and appear to be of importance for outcome, we hypothesized that induction of the kynurenine pathway may be part of the pathophysiological mechanism. Inflammatory biomarkers were analyzed in cerebrospinal fluid from 22 children with tick-borne encephalitis (TBE), 34 children with neuroborreliosis (NB) and 6 children with no central nervous system infection. Cerebrospinal fluid levels of kynurenine and kynurenic acid were increased in children with neuroborreliosis compared to the comparison group. A correlation was seen between expression of several cerebrospinal fluid cytokines and levels of kynurenine and kynurenic acid in children with neuroborreliosis but not in children with tick-borne encephalitis. These findings demonstrate a strong induction of the kynurenine pathway in children with neuroborreliosis which differs from that seen in children with tick-borne encephalitis. The importance of brain kynurenic acid (KYNA) in both immune modulation and neurotransmission raises the possibility that abnormal levels of the compound in neuroborreliosis might be of importance for the pathophysiology of the disease. Drugs targeting the enzymes of this pathway may open the venue for novel therapeutic interventions.
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Affiliation(s)
- Ronny Wickström
- Neuropediatric Unit, Department for Women’s and Children’s Health, Karolinska Institutet, 171 77 Stockholm, Sweden; (R.W.); (S.Y.)
| | - Åsa Fowler
- Division of Paediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 141 52 Stockholm, Sweden;
| | - Michel Goiny
- Department of Physiology & Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Vincent Millischer
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, 1090 Vienna, Austria;
- Department of Molecular Medicine and Surgery (MMK), Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Sofia Ygberg
- Neuropediatric Unit, Department for Women’s and Children’s Health, Karolinska Institutet, 171 77 Stockholm, Sweden; (R.W.); (S.Y.)
| | - Lilly Schwieler
- Department of Physiology & Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden;
- Correspondence: ; Tel.: +46-707489402; Fax: +46-8-310-622
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18
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Prefrontal α7nAChR Signaling Differentially Modulates Afferent Drive and Trace Fear Conditioning Behavior in Adolescent and Adult Rats. J Neurosci 2021; 41:1908-1916. [PMID: 33478990 DOI: 10.1523/jneurosci.1941-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/29/2020] [Accepted: 12/23/2020] [Indexed: 01/22/2023] Open
Abstract
Increased level of kynurenic acid is thought to contribute to the development of cognitive deficits in schizophrenia through an α7nAChR-mediated mechanism in the prefrontal cortex (PFC). However, it remains unclear to what extent disruption of PFC α7nAChR signaling impacts afferent transmission and its modulation of behavior. Using male rats, we found that PFC infusion of methyllycaconitine (MLA; α7nAChR antagonist) shifts ventral hippocampal-induced local field potential (LFP) suppression to LFP facilitation, an effect only observed in adults. Hippocampal stimulation can also elicit a GluN2B-mediated LFP potentiation (when PFC GABAAR is blocked) that is insensitive to MLA. Conversely, PFC infusion of MLA diminished the gain of amygdalar transmission, which is already enabled by postnatal day (P)30. Behaviorally, the impact of prefrontal MLA on trace fear-conditioning and extinction was also age related. While freezing behavior during conditioning was reduced by MLA only in adults, it elicited opposite effects in adolescent and adult rats during extinction as revealed by the level of reduced and increased freezing response, respectively. We next asked whether the late-adolescent onset of α7nAChR modulation of hippocampal inputs contributes to the age-dependent effect of MLA during extinction. Data revealed that the increased freezing behavior elicited by MLA in adult rats could be driven by a dysregulation of the GluN2B transmission in the PFC. Collectively, these results indicate that distinct neural circuits are recruited during the extinction of trace fear memory in adolescents and adults, likely because of the late-adolescent maturation of the ventral hippocampal-PFC functional connectivity and its modulation by α7nAChR signaling.SIGNIFICANCE STATEMENT Abnormal elevation of the astrocyte-derived metabolite kynurenic acid in the prefrontal cortex (PFC) is thought to impair cognitive functions in schizophrenia through an α7nAChR-mediated mechanism. Here, we found that prefrontal α7nAChR signaling is recruited to control the gain of hippocampal and amygdalar afferent transmission in an input-specific, age-related manner during the adolescent transition to adulthood. Behaviorally, prefrontal α7nAChR modulation of trace fear memory was also age-related, likely because of the late-adolescent maturation of the ventral hippocampal pathway and its recruitment of PFC GABAergic transmission enabled by local α7nAChR signaling. Collectively, these results reveal that distinct α7nAChR-sensitive neural circuits contribute to regulate behavior responses in adolescents and adults, particularly those requiring proper integration of hippocampal and amygdalar inputs by the PFC.
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19
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Wright CJ, Rentschler KM, Wagner NTJ, Lewis AM, Beggiato S, Pocivavsek A. Time of Day-Dependent Alterations in Hippocampal Kynurenic Acid, Glutamate, and GABA in Adult Rats Exposed to Elevated Kynurenic Acid During Neurodevelopment. Front Psychiatry 2021; 12:734984. [PMID: 34603109 PMCID: PMC8484637 DOI: 10.3389/fpsyt.2021.734984] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/23/2021] [Indexed: 01/09/2023] Open
Abstract
Hypofunction of glutamatergic signaling is causally linked to neurodevelopmental disorders, including psychotic disorders like schizophrenia and bipolar disorder. Kynurenic acid (KYNA) has been found to be elevated in postmortem brain tissue and cerebrospinal fluid of patients with psychotic illnesses and may be involved in the hypoglutamatergia and cognitive dysfunction experienced by these patients. As insults during the prenatal period are hypothesized to be linked to the pathophysiology of psychotic disorders, we presently utilized the embryonic kynurenine (EKyn) paradigm to induce a prenatal hit. Pregnant Wistar dams were fed chow laced with kynurenine to stimulate fetal brain KYNA elevation from embryonic day 15 to embryonic day 22. Control dams (ECon) were fed unlaced chow. Plasma and hippocampal tissue from young adult (postnatal day 56) ECon and EKyn male and female offspring were collected at the beginning of the light (Zeitgeber time, ZT 0) and dark (ZT 12) phases to assess kynurenine pathway metabolites. Hippocampal tissue was also collected at ZT 6 and ZT 18. In separate animals, in vivo microdialysis was conducted in the dorsal hippocampus to assess extracellular KYNA, glutamate, and γ-aminobutyric acid (GABA). Biochemical analyses revealed no changes in peripheral metabolites, yet hippocampal tissue KYNA levels were significantly impacted by EKyn treatment, and increased in male EKyn offspring at ZT 6. Interestingly, extracellular hippocampal KYNA levels were only elevated in male EKyn offspring during the light phase. Decreases in extracellular glutamate levels were found in the dorsal hippocampus of EKyn male and female offspring, while decreased GABA levels were present only in males during the dark phase. The current findings suggest that the EKyn paradigm may be a useful tool for investigation of sex- and time-dependent changes in hippocampal neuromodulation elicited by prenatal KYNA elevation, which may influence behavioral phenotypes and have translational relevance to psychotic disorders.
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Affiliation(s)
- Courtney J Wright
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Katherine M Rentschler
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Nathan T J Wagner
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Ashley M Lewis
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Sarah Beggiato
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti, Italy
| | - Ana Pocivavsek
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
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20
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Transplantation of microbiota from drug-free patients with schizophrenia causes schizophrenia-like abnormal behaviors and dysregulated kynurenine metabolism in mice. Mol Psychiatry 2020; 25:2905-2918. [PMID: 31391545 DOI: 10.1038/s41380-019-0475-4] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/28/2019] [Accepted: 06/20/2019] [Indexed: 12/18/2022]
Abstract
Accumulating evidence suggests that gut microbiota plays a role in the pathogenesis of schizophrenia via the microbiota-gut-brain axis. This study sought to investigate whether transplantation of fecal microbiota from drug-free patients with schizophrenia into specific pathogen-free mice could cause schizophrenia-like behavioral abnormalities. The results revealed that transplantation of fecal microbiota from schizophrenic patients into antibiotic-treated mice caused behavioral abnormalities such as psychomotor hyperactivity, impaired learning and memory in the recipient animals. These mice also showed elevation of the kynurenine-kynurenic acid pathway of tryptophan degradation in both periphery and brain, as well as increased basal extracellular dopamine in prefrontal cortex and 5-hydroxytryptamine in hippocampus, compared with their counterparts receiving feces from healthy controls. Furthermore, colonic luminal filtrates from the mice transplanted with patients' fecal microbiota increased both kynurenic acid synthesis and kynurenine aminotransferase II activity in cultured hepatocytes and forebrain cortical slices. Sixty species of donor-derived bacteria showed significant difference between the mice colonized with the patients' and the controls' fecal microbiota, highlighting 78 differentially enriched functional modules including tryptophan biosynthesis function. In conclusion, our study suggests that the abnormalities in the composition of gut microbiota contribute to the pathogenesis of schizophrenia partially through the manipulation of tryptophan-kynurenine metabolism.
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21
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Repeated administration of LPS exaggerates amphetamine-induced locomotor response and causes learning deficits in mice. J Neuroimmunol 2020; 349:577401. [PMID: 33002724 DOI: 10.1016/j.jneuroim.2020.577401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 09/03/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022]
Abstract
Immune activation contributes to the pathophysiology of psychiatric disorders. Administration of a single dose of lipopolysaccharides (LPS) has been shown to induce depressive- and anxiety-like behaviors in rodents through activation of the kynurenine pathway, increasing levels of the N-methyl-d-aspartate (NMDA) receptor agonist quinolinic acid. Conversely, repeated administration of LPS produces increased levels of the NMDA receptor antagonist kynurenic acid. Here we show that repeated LPS administration increases sensitivity to D-amphetamine and produces cognitive deficits and anxiety-like behavior. Together, our behavioral data suggests that repeated LPS administration may be useful to study the contribution of inflammation to psychiatric disorders such as schizophrenia.
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22
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Koola MM, Looney SW, Hong H, Pillai A, Hou W. Meta-analysis of randomized controlled trials of galantamine in schizophrenia: significant cognitive enhancement. Psychiatry Res 2020; 291:113285. [PMID: 32763546 DOI: 10.1016/j.psychres.2020.113285] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 12/11/2022]
Abstract
Cognitive impairments are core features of schizophrenia and the best predictor of functional outcome. Cholinergic system and alpha-7 nicotinic acetylcholine (α7nACh) receptors are strongly implicated in the pathophysiologic mechanisms associated with cognitive impairments in schizophrenia. Galantamine is not only a reversible, competitive inhibitor of acetylcholinesterase but also a type I positive allosteric modulator of α7nACh receptors. The objective of this meta-analysis was to examine the efficacy of galantamine for cognitive symptoms of schizophrenia. In the meta-analysis that included six randomized controlled trials (RCTs, N=226), cognitive impairments significantly improved with galantamine compared to placebo, with a small Hedges' g effect size of 0.233. This finding is consistent with other RCTs in schizophrenia with medications with a similar mechanism of action. On the basis of the results from all the failed (although some efficacy has been shown) RCTs to date in schizophrenia, targeting only one pathophysiologic mechanism may be insufficient to detect a clinically meaningful signal. Nicotinergic medications, like any other add-on medications, are unlikely to be effective as stand-alone medications. Hence, these medications may have to be combined with other medications with complementary mechanisms such as glutamatergic/N-methyl-D-aspartate systems to detect a meaningful effect size for the three domains of psychopathology.
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Affiliation(s)
- Maju Mathew Koola
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, 11794, USA.
| | - Stephen W Looney
- Department of Population Health Sciences, Division of Biostatistics and Data Science, Augusta University, Augusta, GA, USA
| | - Houlin Hong
- Department of Family, Population and Preventive Medicine, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Anilkumar Pillai
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wei Hou
- Department of Family, Population and Preventive Medicine, School of Medicine, Stony Brook University, Stony Brook, NY, USA
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23
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Blanco-Ayala T, Sathyasaikumar KV, Uys JD, Pérez-de-la-Cruz V, Pidugu LS, Schwarcz R. N-Acetylcysteine Inhibits Kynurenine Aminotransferase II. Neuroscience 2020; 444:160-169. [PMID: 32768617 DOI: 10.1016/j.neuroscience.2020.07.049] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 07/08/2020] [Accepted: 07/28/2020] [Indexed: 12/22/2022]
Abstract
The tryptophan metabolite kynurenic acid (KYNA) may play an important role in normal and abnormal cognitive processes, most likely by interfering with α7 nicotinic and NMDA receptor function. KYNA is formed from its immediate precursor kynurenine either by non-enzymatic oxidation or through irreversible transamination by kynurenine aminotransferases. In the mammalian brain, kynurenine aminotransferase II (KAT II) is the principal enzyme responsible for the neosynthesis of rapidly mobilizable KYNA, and therefore constitutes an attractive target for pro-cognitive interventions. N-acetylcysteine (NAC), a brain-penetrant drug with pro-cognitive efficacy in humans, has been proposed to exert its actions by increasing the levels of the anti-oxidant glutathione (GSH) in the brain. We report here that NAC, but not GSH, inhibits KAT II activity in brain tissue homogenates from rats and humans with IC50 values in the high micromolar to low millimolar range. With similar potency, the drug interfered with the de novo formation of KYNA in rat brain slices, and NAC was a competitive inhibitor of recombinant human KAT II (Ki: 450 μM). Furthermore, GSH failed to S-glutathionylate recombinant human KAT II treated with the dithiocarbamate drug disulfiram. Shown by microdialysis in the prefrontal cortex of rats treated with kynurenine (50 mg/kg, i.p.), peripheral administration of NAC (500 mg/kg, i.p., 120 and 60 min before the application of kynurenine) reduced KYNA neosynthesis by ∼50%. Together, these results suggest that NAC exerts its neurobiological effects at least in part by reducing cerebral KYNA formation via KAT II inhibition.
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Affiliation(s)
- T Blanco-Ayala
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - K V Sathyasaikumar
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - J D Uys
- Department of Cellular and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, USA
| | - V Pérez-de-la-Cruz
- Laboratorio de Neurobioquimica y Conducta, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A. Ciudad de México, Mexico
| | - L S Pidugu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - R Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
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Buck SA, Baratta AM, Pocivavsek A. Exposure to elevated embryonic kynurenine in rats: Sex-dependent learning and memory impairments in adult offspring. Neurobiol Learn Mem 2020; 174:107282. [PMID: 32738461 DOI: 10.1016/j.nlm.2020.107282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/21/2020] [Accepted: 07/25/2020] [Indexed: 12/14/2022]
Abstract
Distinct abnormalities in kynurenine pathway (KP) metabolism have been reported in various psychiatric disorders, including schizophrenia (SZ). Kynurenic acid (KYNA), a neuroactive metabolite of the KP, is elevated in individuals diagnosed with SZ and has been linked to cognitive impairments seen in the disorder. To further understand the role of KYNA in SZ etiology, we developed a prenatal insult model where kynurenine (100 mg/day) is fed to pregnant Wistar rats from embryonic day (ED) 15 to ED 22. As sex differences in the prevalence and severity of SZ have been observed, we presently investigated the impact of prenatal kynurenine exposure on KP metabolism and spatial learning and memory in male and female offspring. Specifically, brain tissue and plasma from offspring (control: ECon; kynurenine-treated: EKyn) in prepuberty (postnatal day (PD) 21), adolescence (PD 32-35), and adulthood (PD 56-85) were collected. Separate cohorts of adult offspring were tested in the Barnes maze to assess hippocampus- and prefrontal cortex-mediated learning and memory. Plasma tryptophan, kynurenine, and KYNA were unchanged between ECon and EKyn offspring across all three ages. Hippocampal and frontal cortex KYNA were elevated in male EKyn offspring only in adulthood, compared to ECon, while brain KYNA levels were unchanged in adult females. Male EKyn offspring were significantly impaired during acquisition of the Barnes maze and during reversal learning in the task. In female EKyn offspring, learning and memory remained relatively intact. Taken together, our data demonstrate that exposure to elevated kynurenine during the last week of gestation results in intriguing sex differences and further support the EKyn model as an attractive tool to study the pathophysiology of schizophrenia.
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Affiliation(s)
- Silas A Buck
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Annalisa M Baratta
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ana Pocivavsek
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA.
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Klausing AD, Fukuwatari T, Bucci DJ, Schwarcz R. Stress-induced impairment in fear discrimination is causally related to increased kynurenic acid formation in the prefrontal cortex. Psychopharmacology (Berl) 2020; 237:1931-1941. [PMID: 32215686 PMCID: PMC7308198 DOI: 10.1007/s00213-020-05507-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 03/10/2020] [Indexed: 12/11/2022]
Abstract
RATIONALE Stress is related to cognitive impairments which are observed in most major brain diseases. Prior studies showed that the brain concentration of the tryptophan metabolite kynurenic acid (KYNA) is modulated by stress, and that changes in cerebral KYNA levels impact cognition. However, the link between these phenomena has not been tested directly so far. OBJECTIVES To investigate a possible causal relationship between acute stress, KYNA, and fear discrimination. METHODS Adult rats were exposed to one of three acute stressors-predator odor, restraint, or inescapable foot shocks (ISS)-and KYNA in the prefrontal cortex was measured using microdialysis. Corticosterone was analyzed in a subset of rats. Another cohort underwent a fear discrimination procedure immediately after experiencing stress. Different auditory conditioned stimuli (CSs) were either paired with foot shock (CS+) or were non-reinforced (CS-). One week later, fear was assessed by re-exposing rats to each CS. Finally, to test whether stress-induced changes in KYNA causally impacted fear discrimination, a group of rats that received ISS were pre-treated with the selective KYNA synthesis inhibitor PF-04859989. RESULTS ISS caused the greatest increase in circulating corticosterone levels and raised extracellular KYNA levels by ~ 85%. The two other stressors affected KYNA much less (< 25% increase). Moreover, only rats that received ISS were unable to discriminate between CS+ and CS-. PF-04859989 abolished the stress-induced KYNA increase and also prevented the impairment in fear discrimination in animals that experienced ISS. CONCLUSIONS These findings demonstrate a causal connection between stress-induced KYNA increases and cognitive deficits. Pharmacological manipulation of KYNA synthesis therefore offers a novel approach to modulate cognitive processes in stress-related disorders.
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Affiliation(s)
- Alex D Klausing
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Baltimore, MD, 21228, USA
| | - Tsutomu Fukuwatari
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Baltimore, MD, 21228, USA
- Department of Nutrition, School of Human Cultures, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga, 522-8533, Japan
| | - David J Bucci
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Baltimore, MD, 21228, USA.
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Activation of alpha7 nicotinic and NMDA receptors is necessary for performance in a working memory task. Psychopharmacology (Berl) 2020; 237:1723-1735. [PMID: 32162104 PMCID: PMC7313359 DOI: 10.1007/s00213-020-05495-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/19/2020] [Indexed: 10/24/2022]
Abstract
RATIONALE Working memory deficits are present in schizophrenia (SZ) but remain insufficiently resolved by medications. Similar cognitive dysfunctions can be produced acutely in animals by elevating brain levels of kynurenic acid (KYNA). KYNA's effects may reflect interference with the function of both the α7 nicotinic acetylcholine receptor (α7nAChR) and the glycineB site of the NMDA receptor. OBJECTIVES The aim of the present study was to examine, using pharmacological tools, the respective roles of these two receptor sites on performance in a delayed non-match-to-position working memory (WM) task (DNMTP). METHODS DNMTP consisted of 120 trials/session (5, 10, and 15 s delays). Rats received two doses (25 or 100 mg/kg, i.p.) of L-kynurenine (KYN; bioprecursor of KYNA) or L-4-chlorokynurenine (4-Cl-KYN; bioprecursor of the selective glycineB site antagonist 7-Cl-kynurenic acid). Attenuation of KYN- or 4-Cl-KYN-induced deficits was assessed by co-administration of galantamine (GAL, 3 mg/kg) or PAM-2 (1 mg/kg), two positive modulators of α7nAChR function. Reversal of 4-Cl-KYN-induced deficits was examined using D-cycloserine (DCS; 30 mg/kg), a partial agonist at the glycineB site. RESULTS Both KYN and 4-Cl-KYN administration produced dose-related deficits in DNMTP accuracy that were more severe at the longer delays. In KYN-treated rats, these deficits were reversed to control levels by GAL or PAM-2 but not by DCS. In contrast, DCS eliminated performance deficits in 4-Cl-KYN-treated animals. CONCLUSIONS These experiments reveal that both α7nAChR and NMDAR activity are necessary for normal WM accuracy. They provide substantive new support for the therapeutic potential of positive modulators at these two receptor sites in SZ and other major brain diseases.
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Nahomi RB, Nam MH, Rankenberg J, Rakete S, Houck JA, Johnson GC, Stankowska DL, Pantcheva MB, MacLean PS, Nagaraj RH. Kynurenic Acid Protects Against Ischemia/Reperfusion-Induced Retinal Ganglion Cell Death in Mice. Int J Mol Sci 2020; 21:ijms21051795. [PMID: 32151061 PMCID: PMC7084183 DOI: 10.3390/ijms21051795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 02/21/2020] [Accepted: 03/02/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Glaucoma is an optic neuropathy and involves the progressive degeneration of retinal ganglion cells (RGCs), which leads to blindness in patients. We investigated the role of the neuroprotective kynurenic acid (KYNA) in RGC death against retinal ischemia/reperfusion (I/R) injury. Methods: We injected KYNA intravenously or intravitreally to mice. We generated a knockout mouse strain of kynurenine 3-monooxygenase (KMO), an enzyme in the kynurenine pathway that produces neurotoxic 3-hydroxykynurenine. To test the effect of mild hyperglycemia on RGC protection, we used streptozotocin (STZ) induced diabetic mice. Retinal I/R injury was induced by increasing intraocular pressure for 60 min followed by reperfusion and RGC numbers were counted in the retinal flat mounts. Results: Intravenous or intravitreal administration of KYNA protected RGCs against I/R injury. The I/R injury caused a greater loss of RGCs in wild type than in KMO knockout mice. KMO knockout mice had mildly higher levels of fasting blood glucose than wild type mice. Diabetic mice showed significantly lower loss of RGCs when compared with non-diabetic mice subjected to I/R injury. Conclusion: Together, our study suggests that the absence of KMO protects RGCs against I/R injury, through mechanisms that likely involve higher levels of KYNA and glucose.
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Affiliation(s)
- Rooban B. Nahomi
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, University of Colorado, Aurora, CO 80045, USA; (M.-H.N.); (J.R.); (S.R.); (M.B.P.)
- Correspondence: (R.B.N.); (R.H.N.); Tel.: +1-303-724-8824 (R.H.N.)
| | - Mi-Hyun Nam
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, University of Colorado, Aurora, CO 80045, USA; (M.-H.N.); (J.R.); (S.R.); (M.B.P.)
| | - Johanna Rankenberg
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, University of Colorado, Aurora, CO 80045, USA; (M.-H.N.); (J.R.); (S.R.); (M.B.P.)
| | - Stefan Rakete
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, University of Colorado, Aurora, CO 80045, USA; (M.-H.N.); (J.R.); (S.R.); (M.B.P.)
| | - Julie A. Houck
- Division of Endocrinology, Metabolism and Diabetes, School of Medicine, University of Colorado, Aurora, CO 80045, USA; (J.A.H.); (G.C.J.); (P.S.M.)
| | - Ginger C. Johnson
- Division of Endocrinology, Metabolism and Diabetes, School of Medicine, University of Colorado, Aurora, CO 80045, USA; (J.A.H.); (G.C.J.); (P.S.M.)
| | - Dorota L. Stankowska
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA;
| | - Mina B. Pantcheva
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, University of Colorado, Aurora, CO 80045, USA; (M.-H.N.); (J.R.); (S.R.); (M.B.P.)
| | - Paul S. MacLean
- Division of Endocrinology, Metabolism and Diabetes, School of Medicine, University of Colorado, Aurora, CO 80045, USA; (J.A.H.); (G.C.J.); (P.S.M.)
| | - Ram H. Nagaraj
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, University of Colorado, Aurora, CO 80045, USA; (M.-H.N.); (J.R.); (S.R.); (M.B.P.)
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO 80045, USA
- Correspondence: (R.B.N.); (R.H.N.); Tel.: +1-303-724-8824 (R.H.N.)
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28
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Stone TW. Does kynurenic acid act on nicotinic receptors? An assessment of the evidence. J Neurochem 2020; 152:627-649. [PMID: 31693759 PMCID: PMC7078985 DOI: 10.1111/jnc.14907] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023]
Abstract
As a major metabolite of kynurenine in the oxidative metabolism of tryptophan, kynurenic acid is of considerable biological and clinical importance as an endogenous antagonist of glutamate in the central nervous system. It is most active as an antagonist at receptors sensitive to N-methyl-D-aspartate (NMDA) which regulate neuronal excitability and plasticity, brain development and behaviour. It is also thought to play a causative role in hypo-glutamatergic conditions such as schizophrenia, and a protective role in several neurodegenerative disorders, notably Huntington's disease. An additional hypothesis, that kynurenic acid could block nicotinic receptors for acetylcholine in the central nervous system has been proposed as an alternative mechanism of action of kynurenate. However, the evidence for this alternative mechanism is highly controversial, partly because at least eight earlier studies concluded that kynurenic acid blocked NMDA receptors but not nicotinic receptors and five subsequent, independent studies designed to repeat the results have failed to do so. Many studies considered to support the alternative 'nicotinic' hypothesis have been based on the use of analogs of kynurenate such as 7-chloro-kynurenic acid, or putatively nicotinic modulators such as galantamine, but a detailed analysis of the pharmacology of these compounds suggests that the results have often been misinterpreted, especially since the pharmacology of galantamine itself has been disputed. This review examines the evidence in detail, with the conclusion that there is no confirmed, reliable evidence for an antagonist activity of kynurenic acid at nicotinic receptors. Therefore, since there is overwhelming evidence for kynurenate acting at ionotropic glutamate receptors, especially NMDAR glutamate and glycine sites, with some activity at GPR35 sites and Aryl Hydrocarbon Receptors, results with kynurenic acid should be interpreted only in terms of these confirmed sites of action.
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Affiliation(s)
- Trevor W. Stone
- Institute for Neuroscience and PsychologyUniversity of GlasgowGlasgowG12 8QQUK
- Present address:
Kennedy InstituteNDORMSUniversity of OxfordOxfordOX3 7FYUK
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Tarasov VV, Svistunov AA, Chubarev VN, Sologova SS, Mukhortova P, Levushkin D, Somasundaram SG, Kirkland CE, Bachurin SO, Aliev G. Alterations of Astrocytes in the Context of Schizophrenic Dementia. Front Pharmacol 2020; 10:1612. [PMID: 32116664 PMCID: PMC7020441 DOI: 10.3389/fphar.2019.01612] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/10/2019] [Indexed: 12/19/2022] Open
Abstract
The levels of the astrocyte markers (GFAP, S100B) were increased unevenly in patients with schizophrenia. Reactive astrogliosis was found in approximately 70% of patients with schizophrenia. The astrocytes play a major role in etiology and pathogenesis of schizophrenia. Astrocytes produce the components that altered in schizophrenia extracellular matrix system which are involved in inflammation, functioning of interneurons, glio-, and neurotransmitter system, especially glutamate system. Astrocytes activate the interneurons through glutamate release and ATP. Decreased expression of astrocyte glutamate transporters was observed in patients with schizophrenia. Astrocytes influence on N-methyl-d-aspartate (NMDA) receptors via D-serine, an agonist of the glycine-binding site of NMDA receptors, and kynurenic acid, an endogenous antagonist. NMDA receptors, on its turn, control the impulses of dopamine neurons. Therefore following theories of schizophrenia are proposed. They are a) activation of astrocytes for neuroinflammation, b) glutamate and dopamine theory, as astrocyte products control the activity of NMDA receptors, which influence on the dopamine neurons.
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Affiliation(s)
- Vadim V Tarasov
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Andrey A Svistunov
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Vladimir N Chubarev
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Susanna S Sologova
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Polina Mukhortova
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Dmitrii Levushkin
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Siva G Somasundaram
- Department of Biological Sciences, Salem University, Salem, WV, United States
| | - Cecil E Kirkland
- Department of Biological Sciences, Salem University, Salem, WV, United States
| | - Sergey O Bachurin
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Russia
| | - Gjumrakch Aliev
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia.,Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Russia.,Federal State Budgetary Institution, Research Institute of Human Morphology, Russian Federation, Moscow, Russia.,GALLY International Research Institute, San Antonio, TX, United States
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30
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De Picker L, Fransen E, Coppens V, Timmers M, de Boer P, Oberacher H, Fuchs D, Verkerk R, Sabbe B, Morrens M. Immune and Neuroendocrine Trait and State Markers in Psychotic Illness: Decreased Kynurenines Marking Psychotic Exacerbations. Front Immunol 2020; 10:2971. [PMID: 32010121 PMCID: PMC6978914 DOI: 10.3389/fimmu.2019.02971] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/03/2019] [Indexed: 01/18/2023] Open
Abstract
Objective: Different patterns of immune system upregulation are present in the acute vs. post-treatment states of psychotic illness. We explored the existence of state and trait markers in the peripheral immune system and two immune-associated neuroendocrine pathways (IDO and GTP-CH1 pathway) in a longitudinal sample of psychosis patients. We also evaluated the association of these markers with neuropsychiatric symptomatology. Method: Plasma concentrations of peripheral blood markers were measured in a transdiagnostic group of 49 inpatients with acute psychosis and 52 matched healthy control subjects. Samples were obtained in patients within 48 h after hospital admission for an acute psychotic episode (before initiation of antipsychotics), after 1-2 weeks and again after 8 weeks of treatment. Kynurenine, kynurenic acid (KA), 3-hydroxykynurenine (3-HK), quinolinic acid (QA), phenylalanine, tyrosine, nitrite, and neopterin were measured using HPLC and LC-MS/MS analysis. Concentrations of CRP, CCL2 (MCP1) and cytokines were determined with multiplex immunoassay. PANSS interviews and cognitive tests were performed at baseline and follow-up. Mixed model analyses were used to identify trait and state markers. Results: Patients had significantly higher plasma concentrations of CRP, CCL2, IL1RA, and lower concentrations of KA and KA/Kyn at all time points (F7.5-17.5, all p < 0.001). Increased concentrations of IL6, IL8, IL1RA, TNFα, and CCL2 and decreased QA and 3-HK (F8.7-21.0, all p < 0.005) were found in the acute psychotic state and normalized after treatment. Low nitrite concentrations at admission rose sharply after initiation of antipsychotic medication (F42.4, p < 0.001). PANSS positive scale scores during the acute episode correlated with pro-inflammatory immune markers (r ≥ |0.5|), while negative scale scores correlated inversely with IDO pathway markers (r ≥ |0.4|). Normalization of KA and 3-HK levels between admission and follow-up corresponded to a larger improvement of negative symptoms (r = 0.5, p < 0.030) A reverse association was found between relative improvement of SDST scores and decreasing KA levels (r = 0.5, p < 0.010). Conclusion: The acute psychotic state is marked by state-specific increases of immune markers and decreases in peripheral IDO pathway markers. Increased CRP, CCL2, and IL1RA, and decreased KA and KA/Kyn are trait markers of psychotic illness.
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Affiliation(s)
- Livia De Picker
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute, University of Antwerp, Antwerp, Belgium.,University Department of Psychiatry, Campus Duffel, Antwerp, Belgium
| | - Erik Fransen
- StatUa Center for Statistics, University of Antwerp, Antwerp, Belgium
| | - Violette Coppens
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute, University of Antwerp, Antwerp, Belgium.,University Department of Psychiatry, Campus Duffel, Antwerp, Belgium
| | - Maarten Timmers
- Janssen Research and Development, Janssen Pharmaceutica N.V., Beerse, Belgium.,Reference Center for Biological Markers of Dementia (BIODEM), Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Peter de Boer
- Janssen Research and Development, Janssen Pharmaceutica N.V., Beerse, Belgium
| | - Herbert Oberacher
- Core Facility Metabolomics, Institute of Legal Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Dietmar Fuchs
- Biocenter, Division of Biological Chemistry, Medical University of Innsbruck, Innsbruck, Austria
| | - Robert Verkerk
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Bernard Sabbe
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute, University of Antwerp, Antwerp, Belgium.,University Department of Psychiatry, Campus Duffel, Antwerp, Belgium
| | - Manuel Morrens
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute, University of Antwerp, Antwerp, Belgium.,University Department of Psychiatry, Campus Duffel, Antwerp, Belgium
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Abstract
The kynurenine pathway (KP) plays a critical role in generating cellular energy in the form of nicotinamide adenine dinucleotide (NAD+). Because energy requirements are substantially increased during an immune response, the KP is a key regulator of the immune system. Perhaps more importantly in the context of psychiatry, many kynurenines are neuroactive, modulating neuroplasticity and/or exerting neurotoxic effects in part through their effects on NMDA receptor signaling and glutamatergic neurotransmission. As such, it is not surprising that the kynurenines have been implicated in psychiatric illness in the context of inflammation. However, because of their neuromodulatory properties, the kynurenines are not just additional members of a list of inflammatory mediators linked with psychiatric illness, but in preclinical studies have been shown to be necessary components of the behavioral analogs of depression and schizophrenia-like cognitive deficits. Further, as the title suggests, the KP is regulated by, and in turn regulates multiple other physiological systems that are commonly disrupted in psychiatric disorders, including endocrine, metabolic, and hormonal systems. This review provides a broad overview of the mechanistic pathways through which the kynurenines interact with these systems, thus impacting emotion, cognition, pain, metabolic function, and aging, and in so doing potentially increasing the risk of developing psychiatric disorders. Novel therapeutic approaches targeting the KP are discussed. Moreover, electroconvulsive therapy, ketamine, physical exercise, and certain non-steroidal anti-inflammatories have been shown to alter kynurenine metabolism, raising the possibility that kynurenine metabolites may have utility as treatment response or therapeutic monitoring biomarkers.
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Affiliation(s)
- Jonathan Savitz
- Laureate Institute for Brain Research, Tulsa, OK, USA.
- Oxley College of Health Sciences, The University of Tulsa, Tulsa, OK, USA.
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Nakazawa K, Sapkota K. The origin of NMDA receptor hypofunction in schizophrenia. Pharmacol Ther 2019; 205:107426. [PMID: 31629007 DOI: 10.1016/j.pharmthera.2019.107426] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/10/2019] [Indexed: 12/12/2022]
Abstract
N-methyl-d-aspartate (NMDA) receptor (NMDAR) hypofunction plays a key role in pathophysiology of schizophrenia. Since NMDAR hypofunction has also been reported in autism, Alzheimer's disease and cognitive dementia, it is crucial to identify the location, timing, and mechanism of NMDAR hypofunction for schizophrenia for better understanding of disease etiology and for novel therapeutic intervention. In this review, we first discuss the shared underlying mechanisms of NMDAR hypofunction in NMDAR antagonist models and the anti-NMDAR autoantibody model of schizophrenia and suggest that NMDAR hypofunction could occur in GABAergic neurons in both models. Preclinical models using transgenic mice have shown that NMDAR hypofunction in cortical GABAergic neurons, in particular parvalbumin-positive fast-spiking interneurons, in the early postnatal period confers schizophrenia-related phenotypes. Recent studies suggest that NMDAR hypofunction can also occur in PV-positive GABAergic neurons with alterations of NMDAR-associated proteins, such as neuregulin/ErbB4, α7nAChR, and serine racemase. Furthermore, several environmental factors, such as oxidative stress, kynurenic acid and hypoxia, may also potentially elicit NMDAR hypofunction in GABAergic neurons in early postnatal period. Altogether, the studies discussed here support a central role for GABAergic abnormalities in the context of NMDAR hypofunction. We conclude by suggesting potential therapeutic strategies to improve the function of fast-spiking neurons.
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Kynurenines and the Endocannabinoid System in Schizophrenia: Common Points and Potential Interactions. Molecules 2019; 24:molecules24203709. [PMID: 31619006 PMCID: PMC6832375 DOI: 10.3390/molecules24203709] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/09/2019] [Accepted: 10/14/2019] [Indexed: 12/15/2022] Open
Abstract
Schizophrenia, which affects around 1% of the world’s population, has been described as a complex set of symptoms triggered by multiple factors. However, the exact background mechanisms remain to be explored, whereas therapeutic agents with excellent effectivity and safety profiles have yet to be developed. Kynurenines and the endocannabinoid system (ECS) play significant roles in both the development and manifestation of schizophrenia, which have been extensively studied and reviewed previously. Accordingly, kynurenines and the ECS share multiple features and mechanisms in schizophrenia, which have yet to be reviewed. Thus, the present study focuses on the main common points and potential interactions between kynurenines and the ECS in schizophrenia, which include (i) the regulation of glutamatergic/dopaminergic/γ-aminobutyric acidergic neurotransmission, (ii) their presence in astrocytes, and (iii) their role in inflammatory mechanisms. Additionally, promising pharmaceutical approaches involving the kynurenine pathway and the ECS will be reviewed herein.
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Bodkin JA, Coleman MJ, Godfrey LJ, Carvalho CM, Morgan CJ, Suckow RF, Anderson T, Ongur D, Kaufman MJ, Lewandowski KE, Siegel AJ, Waldstreicher E, Grochowski CM, Javitt DC, Rujescu D, Hebbring S, Weinshilboum R, Rodriguez SB, Kirchhoff C, Visscher T, Vuckovic A, Fialkowski A, McCarthy S, Malhotra D, Sebat J, Goff DC, Hudson JI, Lupski JR, Coyle JT, Rudolph U, Levy DL. Targeted Treatment of Individuals With Psychosis Carrying a Copy Number Variant Containing a Genomic Triplication of the Glycine Decarboxylase Gene. Biol Psychiatry 2019; 86:523-535. [PMID: 31279534 PMCID: PMC6745274 DOI: 10.1016/j.biopsych.2019.04.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 04/17/2019] [Accepted: 04/17/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND The increased mutational burden for rare structural genomic variants in schizophrenia and other neurodevelopmental disorders has so far not yielded therapies targeting the biological effects of specific mutations. We identified two carriers (mother and son) of a triplication of the gene encoding glycine decarboxylase, GLDC, presumably resulting in reduced availability of the N-methyl-D-aspartate receptor coagonists glycine and D-serine and N-methyl-D-aspartate receptor hypofunction. Both carriers had a diagnosis of a psychotic disorder. METHODS We carried out two double-blind, placebo-controlled clinical trials of N-methyl-D-aspartate receptor augmentation of psychotropic drug treatment in these two individuals. Glycine was used in the first clinical trial, and D-cycloserine was used in the second one. RESULTS Glycine or D-cycloserine augmentation of psychotropic drug treatment each improved psychotic and mood symptoms in placebo-controlled trials. CONCLUSIONS These results provide two independent proof-of-principle demonstrations of symptom relief by targeting a specific genotype and explicitly link an individual mutation to the pathophysiology of psychosis and treatment response.
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Affiliation(s)
| | | | | | | | | | | | | | - Dost Ongur
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
| | - Marc J. Kaufman
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
| | | | - Arthur J. Siegel
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
| | | | | | - Daniel C. Javitt
- Columbia University Medical Center, New York, NY.,Nathan Kline Institute, Orangeburg, NY
| | - Dan Rujescu
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Scott Hebbring
- Center for Human Genetics, Marshfield Clinic Research Institute, Marshfield, WI
| | | | | | | | | | | | | | | | | | | | - Donald C. Goff
- Nathan Kline Institute, Orangeburg, NY.,Department of Psychiatry, New York University Langone Medical Center, New York, NY
| | - James I. Hudson
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
| | | | - Joseph T. Coyle
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
| | - Uwe Rudolph
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
| | - Deborah L. Levy
- McLean Hospital, Belmont, MA.,Harvard Medical School, Boston, MA
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35
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Yoshida Y, Fujigaki H, Kato K, Yamazaki K, Fujigaki S, Kunisawa K, Yamamoto Y, Mouri A, Oda A, Nabeshima T, Saito K. Selective and competitive inhibition of kynurenine aminotransferase 2 by glycyrrhizic acid and its analogues. Sci Rep 2019; 9:10243. [PMID: 31308447 PMCID: PMC6629613 DOI: 10.1038/s41598-019-46666-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/03/2019] [Indexed: 12/15/2022] Open
Abstract
The enzyme kynurenine aminotransferase (KAT) catalyses the conversion of kynurenine (KYN) to kynurenic acid (KYNA). Although the isozymes KAT1–4 have been identified, KYNA is mainly produced by KAT2 in brain tissues. KNYA is an antagonist of N-methyl-D-aspartate and α-7-nicotinic acetylcholine receptors, and accumulation of KYNA in the brain has been associated with the pathology of schizophrenia. Therefore, KAT2 could be exploited as a therapeutic target for the management of schizophrenia. Although currently available KAT2 inhibitors irreversibly bind to pyridoxal 5′-phosphate (PLP), inhibition via this mechanism may cause adverse side effects because of the presence of other PLP-dependent enzymes. Therefore, we identified novel selective KAT2 inhibitors by screening approximately 13,000 molecules. Among these, glycyrrhizic acid (GL) and its analogues, glycyrrhetinic acid (GA) and carbenoxolone (CBX), were identified as KAT2 inhibitors. These compounds were highly selective for KAT2 and competed with its substrate KYN, but had no effects on the other 3 KAT isozymes. Furthermore, we demonstrated that in complex structures that were predicted in docking calculations, GL, GA and CBX were located on the same surface as the aromatic ring of KYN. These results indicate that GL and its analogues are highly selective and competitive inhibitors of KAT2.
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Affiliation(s)
- Yukihiro Yoshida
- Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan
| | - Hidetsugu Fujigaki
- Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan.
| | - Koichi Kato
- College of Pharmacy, Kinjo Gakuin University, Aichi, 463-8521, Japan.,Faculty of Pharmacy, Meijo University, Aichi, 468-8503, Japan
| | - Kyoka Yamazaki
- Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan
| | - Suwako Fujigaki
- Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan
| | - Kazuo Kunisawa
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan
| | - Yasuko Yamamoto
- Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan
| | - Akihiro Mouri
- Department of Regulatory Science, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan.,Japanese Drug Organization of Appropriate Use and Research, Aichi, 468-0069, Japan
| | - Akifumi Oda
- Faculty of Pharmacy, Meijo University, Aichi, 468-8503, Japan
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan.,Japanese Drug Organization of Appropriate Use and Research, Aichi, 468-0069, Japan
| | - Kuniaki Saito
- Department of Disease Control and Prevention, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan.,Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Aichi, 470-1192, Japan.,Japanese Drug Organization of Appropriate Use and Research, Aichi, 468-0069, Japan.,Human Health Sciences, Graduate School of Medicine and Faculty of Medicine, Kyoto University, Kyoto, 606-8507, Japan
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36
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The ‘Yin’ and the ‘Yang’ of the kynurenine pathway: excitotoxicity and neuroprotection imbalance in stress-induced disorders. Behav Pharmacol 2019; 30:163-186. [DOI: 10.1097/fbp.0000000000000477] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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37
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Investigating KYNA production and kynurenergic manipulation on acute mouse brain slice preparations. Brain Res Bull 2019; 146:185-191. [DOI: 10.1016/j.brainresbull.2018.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/19/2018] [Accepted: 12/26/2018] [Indexed: 01/09/2023]
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38
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Abstract
Cognitive impairments reported across psychiatric conditions (ie, major depressive disorder, bipolar disorder, schizophrenia, and posttraumatic stress disorder) strongly impair the quality of life of patients and the recovery of those conditions. There is therefore a great need for consideration for cognitive dysfunction in the management of psychiatric disorders. The redundant pattern of cognitive impairments across such conditions suggests possible shared mechanisms potentially leading to their development. Here, we review for the first time the possible role of inflammation in cognitive dysfunctions across psychiatric disorders. Raised inflammatory processes (microglia activation and elevated cytokine levels) across diagnoses could therefore disrupt neurobiological mechanisms regulating cognition, including Hebbian and homeostatic plasticity, neurogenesis, neurotrophic factor, the HPA axis, and the kynurenine pathway. This redundant association between elevated inflammation and cognitive alterations across psychiatric disorders hence suggests that a cross-disorder approach using pharmacological and nonpharmacological (ie, physical activity and nutrition) anti-inflammatory/immunomodulatory strategies should be considered in the management of cognition in psychiatry.
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39
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Hajali V, Andersen ML, Negah SS, Sheibani V. Sex differences in sleep and sleep loss-induced cognitive deficits: The influence of gonadal hormones. Horm Behav 2019; 108:50-61. [PMID: 30597139 DOI: 10.1016/j.yhbeh.2018.12.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 12/23/2018] [Accepted: 12/25/2018] [Indexed: 12/30/2022]
Abstract
Males and females can respond differentially to the same environmental stimuli and experimental conditions. Chronic sleep loss is a frequent and growing problem in many modern societies and has a broad variety of negative outcomes for health and well-being. While much has been done to explore the deleterious effects of sleep deprivation (SD) on cognition in both human and animal studies over the last few decades, very little attention has been paid to the part played by sex differences and gonadal steroids in respect of changes in cognitive functions caused by sleep loss. The effects of gonadal hormones on sleep regulation and cognitive performances are well established. Reduced gonadal function in menopausal women and elderly men is associated with sleep disturbances and cognitive decline as well as dementia, which suggests that sex steroids play a key role in modulating these conditions. Finding out whether there are sex differences in respect of the effect of insufficient sleep on cognition, and how neuroendocrine mediators influence cognitive impairment induced by SD could provide valuable insights into the best therapies for each sex. In this review, we aim to highlight the involvement of sex differences and gonadal hormone status on the severity of cognitive deficits induced by sleep deficiency in both human and animal studies.
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Affiliation(s)
- Vahid Hajali
- Department of Neuroscience, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Monica L Andersen
- Departamento de Psicobiologia, Universidade Federal de São Paulo - UNIFESP, Brazil
| | - Sajad Sahab Negah
- Department of Neuroscience, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Vahid Sheibani
- Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran
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40
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Peripheral and central levels of kynurenic acid in bipolar disorder subjects and healthy controls. Transl Psychiatry 2019; 9:37. [PMID: 30696814 PMCID: PMC6351610 DOI: 10.1038/s41398-019-0378-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/26/2018] [Accepted: 01/01/2019] [Indexed: 02/08/2023] Open
Abstract
Metabolites of the kynurenine pathway of tryptophan degradation, in particular, the N-Methyl-D-aspartic acid receptor antagonist kynurenic acid (KYNA), are increasingly recognized as primary pathophysiological promoters in several psychiatric diseases. Studies analyzing central KYNA levels from subjects with psychotic disorders have reported increased levels. However, sample sizes are limited and in contrast many larger studies examining this compound in blood from psychotic patients commonly report a decrease. A major question is to what extent peripheral KYNA levels reflect brain KYNA levels under physiological as well as pathophysiological conditions. Here we measured KYNA in plasma from a total of 277 subjects with detailed phenotypic data, including 163 BD subjects and 114 matched healthy controls (HCs), using an HPLC system. Among them, 94 BD subjects and 113 HCs also had CSF KYNA concentrations analyzed. We observe a selective increase of CSF KYNA in BD subjects with previous psychotic episodes although this group did not display altered plasma KYNA levels. In contrast, BD subjects with ongoing depressive symptoms displayed a tendency to decreased plasma KYNA concentrations but unchanged CSF KYNA levels. Sex and age displayed specific effects on KYNA concentrations depending on if measured centrally or in the periphery. These findings implicate brain-specific regulation of KYNA under physiological as well as under pathophysiological conditions and strengthen our previous observation of CSF KYNA as a biomarker in BD. In summary, biomarker and drug discovery studies should include central KYNA measurements for a more reliable estimation of brain KYNA levels.
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41
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Pocivavsek A, Elmer GI, Schwarcz R. Inhibition of kynurenine aminotransferase II attenuates hippocampus-dependent memory deficit in adult rats treated prenatally with kynurenine. Hippocampus 2018; 29:73-77. [PMID: 30311334 DOI: 10.1002/hipo.23040] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/01/2018] [Accepted: 10/07/2018] [Indexed: 11/11/2022]
Abstract
A combination of genetic and environmental factors contributes to schizophrenia (SZ), a catastrophic psychiatric disorder with a hypothesized neurodevelopmental origin. Increases in the brain levels of the tryptophan metabolite kynurenic acid (KYNA), an endogenous antagonist of α7 nicotinic acetylcholine and NMDA receptors, have been implicated specifically in the cognitive deficits seen in persons with SZ. Here we evaluated this role of KYNA by adding the KYNA precursor kynurenine (100 mg/day) to chow fed to pregnant rat dams from embryonic day (ED) 15 to ED 22 (control: ECon; kynurenine treated: EKyn). Upon termination of the treatment, all rats received normal rodent chow until the animals were evaluated in adulthood (postnatal days 56-85). EKyn treatment resulted in increased extracellular KYNA and reduced extracellular glutamate in the hippocampus, measured by in vivo microdialysis, and caused impairments in hippocampus-dependent learning in adult rats. Acute administration of BFF816, a systemically active inhibitor of kynurenine aminotransferase II (KAT II), the major KYNA-synthesizing enzyme in the brain, normalized neurochemistry and prevented contextual memory deficits in adult EKyn animals. Collectively, these results demonstrate that acute inhibition of KYNA neosynthesis can overcome cognitive impairments that arise as a consequence of elevated brain KYNA in early brain development.
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Affiliation(s)
- Ana Pocivavsek
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Greg I Elmer
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
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42
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Wilson KE, Demyanovich H, Rubin LH, Wehring HJ, Kilday C, Kelly DL. Relationship of Interferon-γ to Cognitive Function in Midlife Women with Schizophrenia. Psychiatr Q 2018; 89:937-946. [PMID: 30051373 DOI: 10.1007/s11126-018-9591-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent literature suggests that schizophrenia is linked to an abnormal response of the immune system. Interferon-γ is a cytokine that acts as a mediator between immune stimulation and the kynurenine pathway and may be related to cognitive abilities. The objectives of the present study are to determine if serum cytokines are correlated with cognitive function differently in patients with schizophrenia compared to controls. Fourteen midlife (30-70 year-old) females with DSM-IV diagnosis of schizophrenia or schizoaffective disorder and 13 midlife control females were analyzed. Cytokines were collected from serum blood draws and analyzed at the Cytokine Core Lab at the University of Maryland, Baltimore. The RBANS, HVLT-R, and UPSA were performed to measure cognition and social performance. The results demonstrate a non-significant difference between interferon-γ levels in women with schizophrenia compared to controls, but this cytokine appears to correlate to cognitive abilities differently in these groups. There were several significant negative correlations between interferon-γ and cognition in midlife patients with schizophrenia, but only one in the midlife control group. The negative correlations between interferon-γ and cognition in patients with schizophrenia suggest the hypothesis that inflammation and the kynurenine pathway have important roles in this disorder.
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Affiliation(s)
- Kathleen E Wilson
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD, USA.
| | - Haley Demyanovich
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD, USA
| | - Leah H Rubin
- Women's Mental Health Research Program, University of Illinois at Chicago, Chicago, IL, USA
| | - Heidi J Wehring
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD, USA
| | - Catherine Kilday
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD, USA
| | - Deanna L Kelly
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD, USA
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43
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Low Serum Tryptophan Levels as an Indicator of Global Cognitive Performance in Nondemented Women over 50 Years of Age. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8604718. [PMID: 30584466 PMCID: PMC6280300 DOI: 10.1155/2018/8604718] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/17/2018] [Accepted: 08/12/2018] [Indexed: 01/03/2023]
Abstract
Aging is a physiological decline process. The number of older adults is growing around the world; therefore, the incidence of cognitive impairment, dementia, and other diseases related to aging increases. The main cellular factors that converge in the aging process are mitochondrial dysfunction, antioxidant impairment, inflammation, and immune response decline, among others. In this context, these cellular changes have an influence on the kynurenine pathway (KP), the main route of tryptophan (Trp) catabolism. KP metabolites have been involved in the aging process and neurodegenerative diseases. Although there are changes in the metabolite levels with age, at this time, there is no study that has evaluated cognitive decline as a consequence of Trp catabolism fluctuation in aging. The aim of this study was to evaluate the relation between the changes in Trp catabolism and cognitive impairment associated with age through KP metabolites level alterations in women over 50 years of age. Seventy-seven nondemented women over 50 years old were examined with a standardized cognitive screening evaluation in Spanish language (Neuropsi), Beck anxiety inventory (BAI), and the geriatric depression scale (GDS). Also, serum levels of Trp, kynurenine (Kyn), kynurenic acid (KYNA), and 3-hydroykynurenine (3-HK) and the glutathione ratio (GSH/GSSG) were measured. Results showed a negative correlation between age and Trp levels and a positive correlation between age and KYNA/Trp and 3-HK/Trp ratios. The level of cognitive impairment showed a significant positive association with age and with kynurenine pathway activation and a significant negative correlation with Trp levels. The GSH/GSSG ratio correlated positively with Trp levels and negatively with Kyn/Trp and 3-HK/Trp ratios. The depression score correlated negatively with Trp and positively with the 3-HK/Trp ratio. We concluded that KP activation increases with age and it is strongly associated with the level of cognition performance in nondemented women over 50 years of age.
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44
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Beggiato S, Notarangelo FM, Sathyasaikumar KV, Giorgini F, Schwarcz R. Maternal genotype determines kynurenic acid levels in the fetal brain: Implications for the pathophysiology of schizophrenia. J Psychopharmacol 2018; 32:1223-1232. [PMID: 30354938 DOI: 10.1177/0269881118805492] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Several studies suggest a pathophysiologically relevant association between increased brain levels of the neuroinhibitory tryptophan metabolite kynurenic acid and cognitive dysfunctions in people with schizophrenia. Elevated kynurenic acid in schizophrenia may be secondary to a genetic alteration of kynurenine 3-monooxygenase, a pivotal enzyme in the kynurenine pathway of tryptophan degradation. In rats, prenatal exposure to kynurenine, the direct bioprecursor of kynurenic acid, induces cognitive impairments reminiscent of schizophrenia in adulthood, suggesting a developmental dimension to the link between kynurenic acid and schizophrenia. AIM The purpose of this study was to explore the possible impact of the maternal genotype on kynurenine pathway metabolism. METHODS We exposed pregnant wild-type ( Kmo+/+ ) and heterozygous ( Kmo+/-) mice to kynurenine (10 mg/day) during the last week of gestation and determined the levels of kynurenic acid and two other neuroactive kynurenine pathway metabolites, 3-hydroxykynurenine and quinolinic acid, in fetal brain and placenta on embryonic day 17/18. RESULTS Maternal kynurenine treatment raised kynurenic acid levels significantly more in the brain of heterozygous offspring of Kmo+/- than in the brain of Kmo+/+ offspring. Conversely, 3-hydroxykynurenine and quinolinic acid levels in the fetal brain tended to be lower in heterozygous animals derived from kynurenine-treated Kmo+/- mice than in corresponding Kmo+/+ offspring. Genotype-related effects on the placenta were qualitatively similar but less pronounced. Kynurenine treatment also caused a preferential elevation in cerebral kynurenic acid levels in Kmo+/- compared to Kmo+/+ dams. CONCLUSIONS The disproportionate kynurenic acid increase in the brain of Kmo+/- animals indicates that the maternal Kmo genotype may play a key role in the pathophysiology of schizophrenia.
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Affiliation(s)
- Sarah Beggiato
- 1 Department of Life Sciences and Biotechnologies, University of Ferrara, Ferrara, Italy.,2 Laboratory for the Technology of Advanced Therapies (LTTA Centre), University of Ferrara, Ferrara, Italy
| | - Francesca M Notarangelo
- 3 Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Flaviano Giorgini
- 4 Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Robert Schwarcz
- 3 Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
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45
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Sharma R, Razdan K, Bansal Y, Kuhad A. Rollercoaster ride of kynurenines: steering the wheel towards neuroprotection in Alzheimer's disease. Expert Opin Ther Targets 2018; 22:849-867. [PMID: 30223691 DOI: 10.1080/14728222.2018.1524877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Alzheimer's disease (AD) is associated with cerebral cognitive deficits exhibiting two cardinal hallmarks: accruement of extracellular amyloid plaques and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein. The currently accessible therapeutic armamentarium merely provides symptomatic relief. Therefore, the cry for prospective neuroprotective strategies seems to be the need of the hour. Areas covered: This review comprehensively establishes correlation between kynurenine pathway (KP) metabolites and AD with major emphasis on its two functionally contrasting neuroactive metabolites i.e. kynurenic acid (KYNA) and quinolinic acid (QUIN) and enlists various clinical studies which hold a potential for future therapeutics in AD. Also, major hypotheses of AD and mechanisms underlying them have been scrutinized with the aim to brush up the readers with basic pathology of AD. Expert opinion: KP is unique in itself as it holds two completely different domains i.e. neurotoxic QUIN and neuroprotective KYNA and disrupted equilibrium between the two has a hand in neurodegeneration. KYNA has long been demonstrated to be neuroprotective but lately being disparaged for cognitive side effects. But we blaze a trail by amalgamating the pharmacological mechanistic studies of KYNA in kinship with α7nAChRs, NMDARs and GABA which lends aid in favour of KA.
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Affiliation(s)
- Radhika Sharma
- a Pharmacology Research Laboratory , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
| | - Karan Razdan
- b Pharmaceutics division , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
| | - Yashika Bansal
- a Pharmacology Research Laboratory , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
| | - Anurag Kuhad
- a Pharmacology Research Laboratory , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
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46
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Baratta AM, Viechweg SS, Mong JA, Pocivavsek A. A High-performance Liquid Chromatography Measurement of Kynurenine and Kynurenic Acid: Relating Biochemistry to Cognition and Sleep in Rats. J Vis Exp 2018. [PMID: 30176006 DOI: 10.3791/58129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The kynurenine pathway (KP) of tryptophan degradation has been implicated in psychiatric disorders. Specifically, the astrocyte-derived metabolite kynurenic acid (KYNA), an antagonist at both N-methyl-d-aspartate (NMDA) and α7 nicotinic acetylcholine (α7nACh) receptors, has been implicated in cognitive processes in health and disease. As KYNA levels are elevated in the brains of patients with schizophrenia, a malfunction at the glutamatergic and cholinergic receptors is believed to be causally related to cognitive dysfunction, a core domain of the psychopathology of the illness. KYNA may play a pathophysiologically significant role in individuals with schizophrenia. It is possible to elevate endogenous KYNA in the rodent brain by treating animals with the direct bioprecursor kynurenine, and preclinical studies in rats have demonstrated that acute elevations in KYNA may impact their learning and memory processes. The current protocol describes this experimental approach in detail and combines a) a biochemical analysis of blood kynurenine levels and brain KYNA formation (using high-performance liquid chromatography), b) behavioral testing to probe the hippocampal-dependent contextual memory (passive avoidance paradigm), and c) an assessment of sleep-wake behavior [telemetric recordings combining electroencephalogram (EEG) and electromyogram (EMG) signals] in rats. Taken together, a relationship between elevated KYNA, sleep, and cognition is studied, and this protocol describes in detail an experimental approach to understanding function outcomes of kynurenine elevation and KYNA formation in vivo in rats. Results obtained through variations of this protocol will test the hypothesis that the KP and KYNA serve pivotal roles in modulating sleep and cognition in health and disease states.
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Affiliation(s)
- Annalisa M Baratta
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine
| | - Shaun S Viechweg
- Department of Pharmacology, University of Maryland School of Medicine
| | - Jessica A Mong
- Department of Pharmacology, University of Maryland School of Medicine
| | - Ana Pocivavsek
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine;
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47
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Chiappelli J, Notarangelo FM, Pocivavsek A, Thomas MAR, Rowland LM, Schwarcz R, Hong LE. Influence of plasma cytokines on kynurenine and kynurenic acid in schizophrenia. Neuropsychopharmacology 2018; 43. [PMID: 29520060 PMCID: PMC6006321 DOI: 10.1038/s41386-018-0038-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abnormalities in the kynurenine pathway (KP) of tryptophan degradation, leading to the dysfunction of neuroactive KP metabolites in the brain, have been implicated in the pathophysiology of schizophrenia (SZ). One plausible mechanism involves dysregulation of various pro-inflammatory cytokines associated with the disease, which affect indoleamine-2,3-dioxygenase (IDO), a key enzyme for tryptophan to kynurenine conversion. In order to test this hypothesis directly, we measured plasma levels of the major KP metabolites kynurenine and kynurenic acid (KYNA), as well as four major cytokines, in a sample of 106 SZ patients and 104 control participants. In contrast to the replicable findings of elevation of KYNA in the central nervous system in SZ, plasma levels of KYNA were significantly lower in SZ compared to controls (p = .004). Kynurenine levels were significantly correlated with levels of interferon-γ (p < .001), which is involved in the regulation of IDO, in both patients and controls. However, although patients had higher levels of interleukin-6 (IL-6) compared to controls (p = .012), IL-6 levels were not correlated with kynurenine or KYNA, and did not explain group differences in KYNA. Based on the lack of evidence that pro-inflammatory cytokines were significantly related to the KP abnormality in SZ despite an adequate sample size, further studies must consider alternative hypotheses to identify the origins of the KP abnormalities in SZ.
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Affiliation(s)
- Joshua Chiappelli
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Francesca M. Notarangelo
- 0000 0001 2175 4264grid.411024.2Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD USA
| | - Ana Pocivavsek
- 0000 0001 2175 4264grid.411024.2Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD USA
| | - Marian A. R. Thomas
- 0000 0001 2175 4264grid.411024.2Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD USA
| | - Laura M. Rowland
- 0000 0001 2175 4264grid.411024.2Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD USA
| | - Robert Schwarcz
- 0000 0001 2175 4264grid.411024.2Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD USA
| | - L. Elliot Hong
- 0000 0001 2175 4264grid.411024.2Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD USA
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48
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Tufvesson-Alm M, Schwieler L, Schwarcz R, Goiny M, Erhardt S, Engberg G. Importance of kynurenine 3-monooxygenase for spontaneous firing and pharmacological responses of midbrain dopamine neurons: Relevance for schizophrenia. Neuropharmacology 2018; 138:130-139. [PMID: 29879409 DOI: 10.1016/j.neuropharm.2018.06.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/01/2018] [Accepted: 06/03/2018] [Indexed: 12/15/2022]
Abstract
Kynurenine 3-monooxygenase (KMO) is an essential enzyme of the kynurenine pathway, converting kynurenine into 3-hydroxykynurenine. Inhibition of KMO increases kynurenine, resulting in elevated levels of kynurenic acid (KYNA), an endogenous N-methyl-d-aspartate and α*7-nicotinic receptor antagonist. The concentration of KYNA is elevated in the brain of patients with schizophrenia, possibly as a result of a reduced KMO activity. In the present study, using in vivo single cell recording techniques, we investigated the electrophysiological characteristics of ventral tegmental area dopamine (VTA DA) neurons and their response to antipsychotic drugs in a KMO knock-out (K/O) mouse model. KMO K/O mice exhibited a marked increase in spontaneous VTA DA neuron activity as compared to wild-type (WT) mice. Furthermore, VTA DA neurons showed clear-cut, yet qualitatively opposite, responses to the antipsychotic drugs haloperidol and clozapine in the two genotypes. The anti-inflammatory drug parecoxib successfully lowered the firing activity of VTA DA neurons in KMO K/O, but not in WT mice. Minocycline, an antibiotic and anti-inflammatory drug, produced no effect in this regard. Taken together, the present data further support the usefulness of KMO K/O mice for studying distinct aspects of the pathophysiology and pharmacological treatment of psychiatric disorders such as schizophrenia.
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Affiliation(s)
| | - Lilly Schwieler
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michel Goiny
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Sophie Erhardt
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Göran Engberg
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institute, Biomedicum 5C, 171 77, Stockholm, Sweden.
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Relevance of Alternative Routes of Kynurenic Acid Production in the Brain. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:5272741. [PMID: 29977455 PMCID: PMC5994304 DOI: 10.1155/2018/5272741] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/24/2018] [Indexed: 01/24/2023]
Abstract
The catabolism of tryptophan has gained great importance in recent years due to the fact that the metabolites produced during this process, with neuroactive and redox properties, are involved in physiological and pathological events. One of these metabolites is kynurenic acid (KYNA), which is considered as a neuromodulator since it can interact with NMDA, nicotinic, and GPR35 receptors among others, modulating the release of neurotransmitters as glutamate, dopamine, and acetylcholine. Kynureninate production is attributed to kynurenine aminotransferases. However, in some physiological and pathological conditions, its high production cannot be explained just with kynurenine aminotransferases. This review focuses on the alternative mechanism whereby KYNA can be produced, either from D-amino acids or by means of other enzymes as D-amino acid oxidase or by the participation of free radicals. It is important to mention that an increase in KYNA levels in processes as brain development, aging, neurodegenerative diseases, and psychiatric disorders, which share common factors as oxidative stress, inflammation, immune response activation, and participation of gut microbiota that can also be related with the alternative routes of KYNA production, has been observed.
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Pocivavsek A, Baratta AM, Mong JA, Viechweg SS. Acute Kynurenine Challenge Disrupts Sleep-Wake Architecture and Impairs Contextual Memory in Adult Rats. Sleep 2018; 40:4210623. [PMID: 29029302 DOI: 10.1093/sleep/zsx141] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Study Objectives Tryptophan metabolism via the kynurenine pathway may represent a key molecular link between sleep loss and cognitive dysfunction. Modest increases in the kynurenine pathway metabolite kynurenic acid (KYNA), which acts as an antagonist at N-methyl-d-aspartate and α7 nicotinic acetylcholine receptors in the brain, result in cognitive impairments. As glutamatergic and cholinergic neurotransmissions are critically involved in modulation of sleep, our current experiments tested the hypothesis that elevated KYNA adversely impacts sleep quality. Methods Adult male Wistar rats were treated with vehicle (saline) and kynurenine (25, 50, 100, and 250 mg/kg), the direct bioprecursor of KYNA, intraperitoneally at zeitgeber time (ZT) 0 to rapidly increase brain KYNA. Levels of KYNA in the brainstem, cortex, and hippocampus were determined at ZT 0, ZT 2, and ZT 4, respectively. Analyses of vigilance state-related parameters categorized as wake, rapid eye movement (REM), and non-REM (NREM) as well as spectra power analysis during NREM and REM were assessed during the light phase. Separate animals were tested in the passive avoidance paradigm, testing contextual memory. Results When KYNA levels were elevated in the brain, total REM duration was reduced and total wake duration was increased. REM and wake architecture, assessed as number of vigilance state bouts and average duration of each bout, and theta power during REM were significantly impacted. Kynurenine challenge impaired performance in the hippocampal-dependent contextual memory task. Conclusions Our results introduce kynurenine pathway metabolism and formation of KYNA as a novel molecular target contributing to sleep disruptions and cognitive impairments.
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Affiliation(s)
- Ana Pocivavsek
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - Annalisa M Baratta
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD
| | - Jessica A Mong
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD
| | - Shaun S Viechweg
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD
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