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Collins JM, Keane JM, Deady C, Khashan AS, McCarthy FP, O'Keeffe GW, Clarke G, Cryan JF, Caputi V, O'Mahony SM. Prenatal stress impacts foetal neurodevelopment: Temporal windows of gestational vulnerability. Neurosci Biobehav Rev 2024; 164:105793. [PMID: 38971516 DOI: 10.1016/j.neubiorev.2024.105793] [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: 04/09/2024] [Revised: 06/27/2024] [Accepted: 07/01/2024] [Indexed: 07/08/2024]
Abstract
Prenatal maternal stressors ranging in severity from everyday occurrences/hassles to the experience of traumatic events negatively impact neurodevelopment, increasing the risk for the onset of psychopathology in the offspring. Notably, the timing of prenatal stress exposure plays a critical role in determining the nature and severity of subsequent neurodevelopmental outcomes. In this review, we evaluate the empirical evidence regarding temporal windows of heightened vulnerability to prenatal stress with respect to motor, cognitive, language, and behavioural development in both human and animal studies. We also explore potential temporal windows whereby several mechanisms may mediate prenatal stress-induced neurodevelopmental effects, namely, excessive hypothalamic-pituitary-adrenal axis activity, altered serotonin signalling and sympathetic-adrenal-medullary system, changes in placental function, immune system dysregulation, and alterations of the gut microbiota. While broadly defined developmental windows are apparent for specific psychopathological outcomes, inconsistencies arise when more complex cognitive and behavioural outcomes are considered. Novel approaches to track molecular markers reflective of the underlying aetiologies throughout gestation to identify tractable biomolecular signatures corresponding to critical vulnerability periods are urgently required.
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Affiliation(s)
- James M Collins
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| | - James M Keane
- APC Microbiome Ireland, University College Cork, Cork, Ireland.
| | - Clara Deady
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| | - Ali S Khashan
- School of Public Health, University College Cork, Cork, Ireland; The Irish Centre for Maternal and Child Health Research (INFANT), Cork University Maternity Hospital, Cork, Ireland.
| | - Fergus P McCarthy
- The Irish Centre for Maternal and Child Health Research (INFANT), Cork University Maternity Hospital, Cork, Ireland; Department of Obstetrics and Gynaecology, University College Cork, Cork, Ireland.
| | - Gerard W O'Keeffe
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; The Irish Centre for Maternal and Child Health Research (INFANT), Cork University Maternity Hospital, Cork, Ireland.
| | - Gerard Clarke
- APC Microbiome Ireland, University College Cork, Cork, Ireland; The Irish Centre for Maternal and Child Health Research (INFANT), Cork University Maternity Hospital, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland.
| | - John F Cryan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| | - Valentina Caputi
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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2
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Ma Y, Gao K, Sun X, Wang J, Yang Y, Wu J, Chai A, Yao L, Liu N, Yu H, Su Y, Lu T, Wang L, Yue W, Zhang X, Xu L, Zhang D, Li J. STON2 variations are involved in synaptic dysfunction and schizophrenia-like behaviors by regulating Syt1 trafficking. Sci Bull (Beijing) 2024; 69:1458-1471. [PMID: 38402028 DOI: 10.1016/j.scib.2024.02.013] [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: 07/04/2023] [Revised: 11/13/2023] [Accepted: 02/06/2024] [Indexed: 02/26/2024]
Abstract
Synaptic dysfunction is a core component of the pathophysiology of schizophrenia. However, the genetic risk factors and molecular mechanisms related to synaptic dysfunction are still not fully understood. The Stonin 2 (STON2) gene encodes a major adaptor for clathrin-mediated endocytosis (CME) of synaptic vesicles. In this study, we showed that the C-C (307Pro-851Ala) haplotype of STON2 increases the susceptibility to schizophrenia and examined whether STON2 variations cause schizophrenia-like behaviors through the regulation of CME. We found that schizophrenia-related STON2 variations led to protein dephosphorylation, which affected its interaction with synaptotagmin 1 (Syt1), a calcium sensor protein located in the presynaptic membrane that is critical for CME. STON2307Pro851Ala knockin mice exhibited deficits in synaptic transmission, short-term plasticity, and schizophrenia-like behaviors. Moreover, among seven antipsychotic drugs, patients with the C-C (307Pro-851Ala) haplotype responded better to haloperidol than did the T-A (307Ser-851Ser) carriers. The recovery of deficits in Syt1 sorting and synaptic transmission by acute administration of haloperidol effectively improved schizophrenia-like behaviors in STON2307Pro851Ala knockin mice. Our findings demonstrated the effect of schizophrenia-related STON2 variations on synaptic dysfunction through the regulation of CME, which might be attractive therapeutic targets for treating schizophrenia-like phenotypes.
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Affiliation(s)
- Yuanlin Ma
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China; The First Affiliated Hospital, Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Kai Gao
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China; Changping Laboratory, Beijing 102206, China
| | - Xiaoxuan Sun
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China
| | - Jinxin Wang
- Chinese Institute for Brain Research, Beijing 102206, China
| | - Yang Yang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China
| | - Jianying Wu
- Chinese Institute for Brain Research, Beijing 102206, China
| | - Anping Chai
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China; Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China
| | - Li Yao
- State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Nan Liu
- State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Hao Yu
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China
| | - Yi Su
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China
| | - Tianlan Lu
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China
| | - Lifang Wang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China
| | - Weihua Yue
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China; PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Xiaohui Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Lin Xu
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
| | - Dai Zhang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China; Changping Laboratory, Beijing 102206, China
| | - Jun Li
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Key Laboratory of Mental Health, Chinese Academy of Medical Sciences, Beijing 100191, China; Changping Laboratory, Beijing 102206, China.
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3
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Hare SM, Adhikari BM, Mo C, Chen S, Wijtenburg SA, Seneviratne C, Kane-Gerard S, Sathyasaikumar KV, Notarangelo FM, Schwarcz R, Kelly DL, Rowland LM, Buchanan RW. Tryptophan challenge in individuals with schizophrenia and healthy controls: acute effects on circulating kynurenine and kynurenic acid, cognition and cerebral blood flow. Neuropsychopharmacology 2023; 48:1594-1601. [PMID: 37118058 PMCID: PMC10516920 DOI: 10.1038/s41386-023-01587-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 04/30/2023]
Abstract
Cognitive impairments predict poor functional outcomes in people with schizophrenia. These impairments may be causally related to increased levels of kynurenic acid (KYNA), a major metabolic product of tryptophan (TRYP). In the brain, KYNA acts as an antagonist of the of α7-nicotinic acetylcholine and NMDA receptors, both of which are involved in cognitive processes. To examine whether KYNA plays a role in the pathophysiology of schizophrenia, we compared the acute effects of a single oral dose of TRYP (6 g) in 32 healthy controls (HC) and 37 people with either schizophrenia (Sz), schizoaffective or schizophreniform disorder, in a placebo-controlled, randomized crossover study. We examined plasma levels of KYNA and its precursor kynurenine; selected cognitive measures from the MATRICS Consensus Cognitive Battery; and resting cerebral blood flow (CBF) using arterial spin labeling imaging. In both cohorts, the TRYP challenge produced significant, time-dependent elevations in plasma kynurenine and KYNA. The resting CBF signal (averaged across all gray matter) was affected differentially, such that TRYP was associated with higher CBF in HC, but not in participants with a Sz-related disorder. While TRYP did not significantly impair cognitive test performance, there was a trend for TRYP to worsen visuospatial memory task performance in HC. Our results demonstrate that oral TRYP challenge substantially increases plasma levels of kynurenine and KYNA in both groups, but exerts differential group effects on CBF. Future studies are required to investigate the mechanisms underlying these CBF findings, and to evaluate the impact of KYNA fluctuations on brain function and behavior. (Clinicaltrials.gov: NCT02067975).
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Affiliation(s)
- Stephanie M Hare
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Bhim M Adhikari
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Chen Mo
- Harvard Medical School, Boston, MA, 02115, USA
| | - Shuo Chen
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - S Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Chamindi Seneviratne
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Samuel Kane-Gerard
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Korrapati V Sathyasaikumar
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Francesca M Notarangelo
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Deanna L Kelly
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Laura M Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Robert W Buchanan
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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4
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Marszalek-Grabska M, Gawel K, Kosheva N, Kocki T, Turski WA. Developmental Exposure to Kynurenine Affects Zebrafish and Rat Behavior. Cells 2023; 12:2224. [PMID: 37759447 PMCID: PMC10526278 DOI: 10.3390/cells12182224] [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: 08/10/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Proper nutrition and supplementation during pregnancy and breastfeeding are crucial for the development of offspring. Kynurenine (KYN) is the central metabolite of the kynurenine pathway and a direct precursor of other metabolites that possess immunoprotective or neuroactive properties, with the ultimate effect on fetal neurodevelopment. To date, no studies have evaluated the effects of KYN on early embryonic development. Thus, the aim of our study was to determine the effect of incubation of larvae with KYN in different developmental periods on the behavior of 5-day-old zebrafish. Additionally, the effects exerted by KYN administered on embryonic days 1-7 (ED 1-7) on the behavior of adult offspring of rats were elucidated. Our study revealed that the incubation with KYN induced changes in zebrafish behavior, especially when zebrafish embryos or larvae were incubated with KYN from 1 to 72 h post-fertilization (hpf) and from 49 to 72 hpf. KYN administered early during pregnancy induced subtle differences in the neurobehavioral development of adult offspring. Further research is required to understand the mechanism of these changes. The larval zebrafish model can be useful for studying disturbances in early brain development processes and their late behavioral consequences. The zebrafish-medium system may be applicable in monitoring drug metabolism in zebrafish.
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Affiliation(s)
- Marta Marszalek-Grabska
- Department of Experimental and Clinical Pharmacology, Medical University, Jaczewskiego 8b, 20-090 Lublin, Poland; (K.G.); (N.K.); (T.K.); (W.A.T.)
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5
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Sapienza J, Spangaro M, Guillemin GJ, Comai S, Bosia M. Importance of the dysregulation of the kynurenine pathway on cognition in schizophrenia: a systematic review of clinical studies. Eur Arch Psychiatry Clin Neurosci 2023; 273:1317-1328. [PMID: 36460745 DOI: 10.1007/s00406-022-01519-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/15/2022] [Indexed: 12/04/2022]
Abstract
Schizophrenia is a chronic psychotic disease burdened by cognitive deficits which hamper daily functioning causing disability and costs for society. Biological determinants underlying cognitive impairment are only partially understood and there are no convincing pharmacological targets able to improve cognitive outcome. Mounting evidence has shown the involvement of the kynurenine pathway in the pathophysiology of schizophrenia, also concerning cognitive symptoms. Therefore, the action of specific metabolites of kynurenine could affects cognition in schizophrenia. To evaluate the impact of the metabolites of kynurenine pathway on cognitive functions in schizophrenia spectrum disorders, with a focus on the modulating role of gender, to identify predictors of cognitive functioning and hypothetical pharmacological targets able to resize disability by improving cognition, thus functioning and quality of life. A systematic review was performed in PubMed/MEDLINE and Embase according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. All studies measuring the direct impact of kynurenine metabolites on cognitive performances in living individuals with schizophrenia spectrum disorders were included in the review. Six studies were included. The activation of the kynurenine pathway resulted associated with greater cognitive deficits in patients with schizophrenia and both elevations and reduction of metabolites seemed able to affect cognitive outcome. No modulating role of sex emerged. This systematic review provides evidence that the activation of the kynurenine pathway affects cognition in patients with schizophrenia and highlights this pathway as a possible future target for developing novel drugs toward this still unmet clinical need. However, evidence is still limited and future studies are needed to further clarify the relationship between kynurenine pathway and cognition in schizophrenia.
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Affiliation(s)
| | | | - Gilles J Guillemin
- Neuroinflammation Group, Macquarie Medicine School, Macquarie University, Sydney, NSW, Australia
| | - Stefano Comai
- IRCCS San Raffaele Scientific Institute, Milan, Italy.
- Department of Psychiatry, McGill University, Montreal, QC, Canada.
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy.
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
| | - Marta Bosia
- IRCCS San Raffaele Scientific Institute, Milan, Italy
- School of Medicine, Vita Salute San Raffaele University, Milan, Italy
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6
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Murakami Y, Imamura Y, Kasahara Y, Yoshida C, Momono Y, Fang K, Sakai D, Konishi Y, Nishiyama T. Maternal Inflammation with Elevated Kynurenine Metabolites Is Related to the Risk of Abnormal Brain Development and Behavioral Changes in Autism Spectrum Disorder. Cells 2023; 12:1087. [PMID: 37048160 PMCID: PMC10093447 DOI: 10.3390/cells12071087] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/27/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023] Open
Abstract
Several studies show that genetic and environmental factors contribute to the onset and progression of neurodevelopmental disorders. Maternal immune activation (MIA) during gestation is considered one of the major environmental factors driving this process. The kynurenine pathway (KP) is a major route of the essential amino acid L-tryptophan (Trp) catabolism in mammalian cells. Activation of the KP following neuro-inflammation can generate various endogenous neuroactive metabolites that may impact brain functions and behaviors. Additionally, neurotoxic metabolites and excitotoxicity cause long-term changes in the trophic support, glutamatergic system, and synaptic function following KP activation. Therefore, investigating the role of KP metabolites during neurodevelopment will likely promote further understanding of additional pathophysiology of neurodevelopmental disorders, including autism spectrum disorder (ASD). In this review, we describe the changes in KP metabolism in the brain during pregnancy and represent how maternal inflammation and genetic factors influence the KP during development. We overview the patients with ASD clinical data and animal models designed to verify the role of perinatal KP elevation in long-lasting biochemical, neuropathological, and behavioral deficits later in life. Our review will help shed light on new therapeutic strategies and interventions targeting the KP for neurodevelopmental disorders.
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Affiliation(s)
- Yuki Murakami
- Department of Hygiene and Public Health, Kansai Medical University, Hirakata 573-1010, Japan
| | - Yukio Imamura
- Department of Architecture and Architectual Systems Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan
- Department of Traumatology and Acute Critical Medicine, Graduate School of Medicine/Faculty of Medicine, Osaka University, Suita 565-0871, Japan
| | - Yoshiyuki Kasahara
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Chihiro Yoshida
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yuta Momono
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Ke Fang
- Department of Hygiene and Public Health, Kansai Medical University, Hirakata 573-1010, Japan
| | - Daisuke Sakai
- Department of Biology, Kanazawa Medical University, Kanazawa 920-0293, Japan
| | - Yukuo Konishi
- Center for Baby Science, Doshisha University, Kyotanabe 619-0225, Japan
- Healthcare and Medical Data Multi-Level Integration Platform Group, RIKEN Medical Sciences Innovation Hub Program, Yokohama 230-0045, Japan
| | - Toshimasa Nishiyama
- Department of Hygiene and Public Health, Kansai Medical University, Hirakata 573-1010, Japan
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Milosavljevic S, Smith AK, Wright CJ, Valafar H, Pocivavsek A. Kynurenine aminotransferase II inhibition promotes sleep and rescues impairments induced by neurodevelopmental insult. Transl Psychiatry 2023; 13:106. [PMID: 37002202 PMCID: PMC10066394 DOI: 10.1038/s41398-023-02399-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 04/03/2023] Open
Abstract
Dysregulated sleep is commonly reported in individuals with neuropsychiatric disorders, including schizophrenia (SCZ) and bipolar disorder (BPD). Physiology and pathogenesis of these disorders points to aberrant metabolism, during neurodevelopment and adulthood, of tryptophan via the kynurenine pathway (KP). Kynurenic acid (KYNA), a neuroactive KP metabolite derived from its precursor kynurenine by kynurenine aminotransferase II (KAT II), is increased in the brains of individuals with SCZ and BPD. We hypothesize that elevated KYNA, an inhibitor of glutamatergic and cholinergic neurotransmission, contributes to sleep dysfunction. Employing the embryonic kynurenine (EKyn) paradigm to elevate fetal brain KYNA, we presently examined pharmacological inhibition of KAT II to reduce KYNA in adulthood to improve sleep quality. Pregnant Wistar rats were fed either kynurenine (100 mg/day)(EKyn) or control (ECon) diet from embryonic day (ED) 15 to ED 22. Adult male (N = 24) and female (N = 23) offspring were implanted with devices to record electroencephalogram (EEG) and electromyogram (EMG) telemetrically for sleep-wake data acquisition. Each subject was treated with either vehicle or PF-04859989 (30 mg/kg, s.c.), an irreversible KAT II inhibitor, at zeitgeber time (ZT) 0 or ZT 12. KAT II inhibitor improved sleep architecture maintaining entrainment of the light-dark cycle; ZT 0 treatment with PF-04859989 induced transient improvements in rapid eye movement (REM) and non-REM (NREM) sleep during the immediate light phase, while the impact of ZT 12 treatment was delayed until the subsequent light phase. PF-04859989 administration at ZT 0 enhanced NREM delta spectral power and reduced activity and body temperature. In conclusion, reducing de novo KYNA production alleviated sleep disturbances and increased sleep quality in EKyn, while also improving sleep outcomes in ECon offspring. Our findings place attention on KAT II inhibition as a novel mechanistic approach to treating disrupted sleep behavior with potential translational implications for patients with neurodevelopmental and neuropsychiatric disorders.
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Affiliation(s)
- Snezana Milosavljevic
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Andrew K Smith
- Department of Computer Science and Engineering, University of South Carolina, Columbia, SC, USA
| | - Courtney J Wright
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Homayoun Valafar
- Department of Computer Science and Engineering, University of South Carolina, Columbia, SC, USA
| | - Ana Pocivavsek
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA.
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8
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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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9
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Marszalek-Grabska M, Zakrocka I, Budzynska B, Marciniak S, Kaszubska K, Lemieszek MK, Winiarczyk S, Kotlinska JH, Rzeski W, Turski WA. Binge-like mephedrone treatment induces memory impairment concomitant with brain kynurenic acid reduction in mice. Toxicol Appl Pharmacol 2022; 454:116216. [PMID: 36057403 DOI: 10.1016/j.taap.2022.116216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/02/2022] [Accepted: 08/26/2022] [Indexed: 10/31/2022]
Abstract
While mephedrone (4-methylmethcathinone), a synthetic cathinone derivative, is widely abused by adolescents and young adults, the knowledge about its long-term effects on memory processes is limited. Kynurenic acid (KYNA) is a neuroactive metabolite of the kynurenine pathway of tryptophan degradation. KYNA is considered an important endogenous modulator influencing physiological and pathological processes, including learning and memory processes. The aim of this study was to determine whether (A) binge-like mephedrone administration (10.0 and 30.0 mg/kg, intraperitoneally, in 4 doses separated by 2 h) induces memory impairments, assessed 2, 8 and 15 days after mephedrone cessation in the passive avoidance test in mice, and whether (B) KYNA is involved in these memory processes. To clarify the role of KYNA in the mephedrone effects, its level in the murine brain in vivo, and in cortical slices in vitro, as well as the activities of kynurenine aminotransferases (KATs) I and II were assessed. Furthermore, cell line experiments were conducted to investigate the effects of mephedrone on normal human brain cells. Our results showed memory impairments 8 and 15 days after binge-like mephedrone administration. At the same time, reduction in the KYNA level in the murine brain was noted. In vitro studies showed no effect of mephedrone on the production of KYNA in cortical slices or on the activity of the KAT I and II enzymes. Finally, exposure of normal cells to mephedrone in vitro resulted in a modest reduction of cell viability and proliferation.
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Affiliation(s)
- Marta Marszalek-Grabska
- Department of Experimental and Clinical Pharmacology, Medical University, Jaczewskiego 8b, 20-090 Lublin, Poland.
| | - Izabela Zakrocka
- Department of Nephrology, Medical University, Jaczewskiego 8, 20-090 Lublin, Poland
| | - Barbara Budzynska
- Independent Laboratory of Behavioral Studies, Medical University, Chodzki 4a, 20-090 Lublin, Poland
| | - Sebastian Marciniak
- Department of Pharmacology, Medical University, Chodźki 4a, 20-093 Lublin, Poland
| | - Katarzyna Kaszubska
- Department of Pharmacology and Pharmacodynamics, Medical University, Chodzki 4a, 20-093 Lublin, Poland
| | - Marta Kinga Lemieszek
- Department of Medical Biology, Institute of Rural Health, Jaczewskiego 2, 20-090 Lublin, Poland
| | - Sylwia Winiarczyk
- Department of Medical Biology, Institute of Rural Health, Jaczewskiego 2, 20-090 Lublin, Poland
| | - Jolanta H Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Chodzki 4a, 20-093 Lublin, Poland
| | - Wojciech Rzeski
- Department of Medical Biology, Institute of Rural Health, Jaczewskiego 2, 20-090 Lublin, Poland; Department of Functional Anatomy and Cytobiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Waldemar A Turski
- Department of Experimental and Clinical Pharmacology, Medical University, Jaczewskiego 8b, 20-090 Lublin, Poland
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10
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Yue W, Huang H, Duan J. Potential diagnostic biomarkers for schizophrenia. MEDICAL REVIEW (BERLIN, GERMANY) 2022; 2:385-416. [PMID: 37724326 PMCID: PMC10388817 DOI: 10.1515/mr-2022-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/20/2022] [Indexed: 09/20/2023]
Abstract
Schizophrenia (SCH) is a complex and severe mental disorder with high prevalence, disability, mortality and carries a heavy disease burden, the lifetime prevalence of SCH is around 0.7%-1.0%, which has a profound impact on the individual and society. In the clinical practice of SCH, key problems such as subjective diagnosis, experiential treatment, and poor overall prognosis are still challenging. In recent years, some exciting discoveries have been made in the research on objective biomarkers of SCH, mainly focusing on genetic susceptibility genes, metabolic indicators, immune indices, brain imaging, electrophysiological characteristics. This review aims to summarize the biomarkers that may be used for the prediction and diagnosis of SCH.
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Affiliation(s)
- Weihua Yue
- Institute of Mental Health, Peking University Sixth Hospital, Beijing, China
- National Clinical Research Center for Mental Disorders & NHC Key Laboratory of Mental Health (Peking University) and Chinese Academy of Medical Sciences Research Unit, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
| | - Hailiang Huang
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Jubao Duan
- Center for Psychiatric Genetics, NorthShore University Health System, Evanston, IL, USA
- Department of Psychiatry and Behavioral Neurosciences, University of Chicago, Chicago, IL, USA
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11
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Mezo-González CE, Daher Abdi A, Reyes-Castro LA, Olvera Hernández S, Almeida C, Croyal M, Aguesse A, Gavioli EC, Zambrano E, Bolaños-Jiménez F. Learning Deficits Induced by High-Calorie Feeding in the Rat are Associated With Impaired Brain Kynurenine Pathway Metabolism. Int J Tryptophan Res 2022; 15:11786469221111116. [PMID: 35846874 PMCID: PMC9277427 DOI: 10.1177/11786469221111116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/14/2022] [Indexed: 11/17/2022] Open
Abstract
In addition to be a primary risk factor for type 2 diabetes and cardiovascular
disease, obesity is associated with learning disabilities. Here we examined
whether a dysregulation of the kynurenine pathway (KP) of tryptophan (Trp)
metabolism might underlie the learning deficits exhibited by obese individuals.
The KP is initiated by the enzymatic conversion of Trp into kynurenine (KYN) by
indoleamine 2,3-dioxygenase (IDO). KYN is further converted to several signaling
molecules including quinolinic acid (QA) which has a negative impact on
learning. Wistar rats were fed either standard chow or made obese by exposure to
a free choice high-fat high-sugar (fcHFHS) diet. Their learning capacities were
evaluated using a combination of the novel object recognition and the novel
object location tasks, and the concentrations of Trp and KYN-derived metabolites
in several brain regions determined by ultra-performance liquid
chromatography-tandem mass spectrometry. Male, but not female, obese rats
exhibited reduced learning capacity characterized by impaired encoding along
with increased hippocampal concentrations of QA, Xanthurenic acid (XA),
Nicotinamide (Nam), and oxidized Nicotinamide Adenine Dinucleotide (NAD+). In
contrast, no differences were detected in the serum levels of Trp or KP
metabolites. Moreover, obesity enhanced the expression in the hippocampus and
frontal cortex of kynurenine monooxygenase (KMO), an enzyme involved in the
production of QA from kynurenine. QA stimulates the glutamatergic system and its
increased production leads to cognitive impairment. These results suggest that
the deleterious effects of obesity on cognition are sex dependent and that
altered KP metabolism might contribute to obesity-associated learning
disabilities.
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Affiliation(s)
| | - Amran Daher Abdi
- UMR Physiologie des Adaptations Nutritionnelles, INRAE - Université de Nantes, Nantes France
| | - Luis Antonio Reyes-Castro
- UMR Physiologie des Adaptations Nutritionnelles, INRAE - Université de Nantes, Nantes France.,Reproductive Biology Department, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, México
| | - Sandra Olvera Hernández
- UMR Physiologie des Adaptations Nutritionnelles, INRAE - Université de Nantes, Nantes France.,Medical and Psychology School, Autonomous University of Baja California, Tijuana, Mexico
| | - Clarissa Almeida
- Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Mikaël Croyal
- CRNH-O Mass Spectrometry Core Facility, Nantes, France.,Université de Nantes, CNRS, INSERM, L'institut du Thorax, Nantes, France.,Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, Nantes, France
| | | | - Elaine Cristina Gavioli
- Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Elena Zambrano
- Reproductive Biology Department, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, México
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12
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Lidgard B, Bansal N, Zelnick LR, Hoofnagle A, Chen J, Colaizzo D, Dobre M, Mills KT, Porter AC, Rosas SE, Sarnak MJ, Seliger S, Sondheimer J, Tamura MK, Yaffe K, Kestenbaum B. Association of Proximal Tubular Secretory Clearance with Long-Term Decline in Cognitive Function. J Am Soc Nephrol 2022; 33:1391-1401. [PMID: 35444055 PMCID: PMC9257801 DOI: 10.1681/asn.2021111435] [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: 11/08/2021] [Accepted: 04/05/2022] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND People with chronic kidney disease (CKD) are at high risk for cognitive impairment and progressive cognitive decline. Retention of protein-bound organic solutes that are normally removed by tubular secretion is hypothesized to contribute to cognitive impairment in CKD. METHODS We followed 2362 participants who were initially free of cognitive impairment and stroke in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study. We estimated tubular secretory clearance by the 24-hour kidney clearances of eight endogenous solutes that are primarily eliminated by tubular secretion. CRIC study investigators assessed participants' cognitive function annually using the Modified Mini-Mental State (3MS) Examination. Cognitive decline was defined as a sustained decrease of more than five points in the 3MS score from baseline. Using Cox regression models adjusted for potential confounders, we analyzed associations between secretory solute clearances, serum solute concentrations, and cognitive decline. RESULTS The median number of follow-up 3MS examinations was six per participant. There were 247 incident cognitive decline events over a median of 9.1 years of follow-up. Lower kidney clearances of five of the eight secretory solutes (cinnamoylglycine, isovalerylglycine, kynurenic acid, pyridoxic acid, and tiglylglycine) were associated with cognitive decline after adjustment for baseline eGFR, proteinuria, and other confounding variables. Effect sizes ranged from a 17% to a 34% higher risk of cognitive decline per 50% lower clearance. In contrast, serum concentrations of the solutes were not associated with cognitive decline. CONCLUSIONS Lower kidney clearances of secreted solutes are associated with incident global cognitive decline in a prospective study of CKD, independent of eGFR. Further work is needed to determine the domains of cognition most affected by decreased secretory clearance and the mechanisms of these associations.
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Affiliation(s)
- Benjamin Lidgard
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
| | - Nisha Bansal
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
| | - Leila R. Zelnick
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
| | - Andrew Hoofnagle
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
| | - Jing Chen
- Department of Medicine, Tulane University, New Orleans, Louisiana
| | | | - Mirela Dobre
- Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | | | - Anna C. Porter
- Department of Medicine, Section of Nephrology, University of Illinois at Chicago, Chicago, Illinois
| | - Sylvia E. Rosas
- Kidney and Hypertension Unit, Joslin Diabetes Center, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Mark J. Sarnak
- Department of Medicine, Tufts Medical Center, Boston, Massachusetts
| | - Stephen Seliger
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - James Sondheimer
- Department of Medicine, Division of Nephrology, Wayne State University, Detroit, Michigan
| | - Manjula Kurella Tamura
- Department of Medicine, Stanford University and VA Palo Alto Health Care System, Palo Alto, California
| | - Kristine Yaffe
- Departments of Psychiatry, Neurology, Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, California
| | - Bryan Kestenbaum
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
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13
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Martos D, Tuka B, Tanaka M, Vécsei L, Telegdy G. Memory Enhancement with Kynurenic Acid and Its Mechanisms in Neurotransmission. Biomedicines 2022; 10:biomedicines10040849. [PMID: 35453599 PMCID: PMC9027307 DOI: 10.3390/biomedicines10040849] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 03/28/2022] [Accepted: 04/02/2022] [Indexed: 02/04/2023] Open
Abstract
Kynurenic acid (KYNA) is an endogenous tryptophan (Trp) metabolite known to possess neuroprotective property. KYNA plays critical roles in nociception, neurodegeneration, and neuroinflammation. A lower level of KYNA is observed in patients with neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases or psychiatric disorders such as depression and autism spectrum disorders, whereas a higher level of KYNA is associated with the pathogenesis of schizophrenia. Little is known about the optimal concentration for neuroprotection and the threshold for neurotoxicity. In this study the effects of KYNA on memory functions were investigated by passive avoidance test in mice. Six different doses of KYNA were administered intracerebroventricularly to previously trained CFLP mice and they were observed for 24 h. High doses of KYNA (i.e., 20–40 μg/2 μL) significantly decreased the avoidance latency, whereas a low dose of KYNA (0.5 μg/2 μL) significantly elevated it compared with controls, suggesting that the low dose of KYNA enhanced memory function. Furthermore, six different receptor blockers were applied to reveal the mechanisms underlying the memory enhancement induced by KYNA. The series of tests revealed the possible involvement of the serotonergic, dopaminergic, α and β adrenergic, and opiate systems in the nootropic effect. This study confirmed that a low dose of KYNA improved a memory component of cognitive domain, which was mediated by, at least in part, four systems of neurotransmission in an animal model of learning and memory.
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Affiliation(s)
- Diána Martos
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - Bernadett Tuka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - Masaru Tanaka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - László Vécsei
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-342-361
| | - Gyula Telegdy
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 5, H-6725 Szeged, Hungary;
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14
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Beggiato S, Ieraci A, Zuccarini M, Di Iorio P, Schwarcz R, Ferraro L. Alterations in rat prefrontal cortex kynurenic acid levels are involved in the enduring cognitive dysfunctions induced by tetrahydrocannabinol exposure during the adolescence. Front Psychiatry 2022; 13:996406. [PMID: 36483135 PMCID: PMC9722723 DOI: 10.3389/fpsyt.2022.996406] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 11/01/2022] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Cannabis abuse during adolescence is a risk factor for cognitive impairments in psychiatric disorders later in life. To date, the possible causal relationship between cannabinoids, kynurenic acid (KYNA; i.e., a neuroactive metabolite of tryptophan degradation) and cognition has not been investigated in adolescence. Early exposure to delta 9-tetrahydrocannabinol (THC; i.e., the main psychotropic component of cannabis) causes enduring cognitive deficits, which critically involve impaired glutamatergic function in the prefrontal cortex (PFC). In addition, prenatal cannabis exposure results in enduring increases in PFC KYNA levels. Based on these findings, the effects of chronic THC exposure in rats, during another critical period of neurodevelopment particularly sensitive to perturbation by exogenous stimuli, such as adolescence, have been investigated. METHODS Male Wistar rats were chronically treated with vehicle or ascending intraperitoneal (i.p.) doses of THC starting on postnatal day (PND) 35 until PND 45. In adulthood (PND 75), cognitive assessment (Y-maze) and extracellular KYNA/glutamate levels were measured in the PFC by in vivo microdialysis, before and after a challenge with KYN (5 mg/kg i.p., the biological precursor of KYNA). By using the selective, brain-penetrable KAT II inhibitor PF-04859989, we then examined whether blockade of KYNA neosynthesis prevents the cognitive impairment. RESULTS Compared to vehicle-treated controls, extracellular basal KYNA levels were higher in the PFC of adult rats chronically exposed to THC in adolescence (p < 0.01). No changes were observed in extracellular glutamate levels. Following a challenge with KYN, extracellular KYNA levels similarly increased in both groups (i.e., vehicle- and THC-treated; p < 0.001 and p < 0.01, respectively). Chronic adolescent THC exposure negatively affected short-term memory (reduced spontaneous alternation), in adult animals (p < 0.001), while PF-04859989 (30 mg/kg i.p.) restored the cognitive impairment (p < 0.05). DISCUSSION We propose that the observed alterations in PFC KYNA signaling might be involved in the cognitive dysfunction induced by the exposure to THC during the adolescence. In the translational realm, these experiments raise the prospect of prevention of KYNA neosynthesis as a possible novel approach to counteract some of the detrimental long-term effects of adolescence cannabis use.
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Affiliation(s)
- Sarah Beggiato
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti, Italy.,Department of Life Sciences and Biotechnologies, University of Ferrara, Ferrara, Italy
| | - Alessandro Ieraci
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy.,Department of Theoretical and Applied Science, eCampus University, Novedrate, Italy
| | - Mariachiara Zuccarini
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti, Italy
| | - Patrizia Di Iorio
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti, Italy
| | - Robert Schwarcz
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Luca Ferraro
- Department of Life Sciences and Biotechnologies, University of Ferrara, Ferrara, Italy.,Laboratory for the Technology of Advanced Therapies (LTTA Centre), University of Ferrara, Ferrara, Italy
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15
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Reiss JD, Peterson LS, Nesamoney SN, Chang AL, Pasca AM, Marić I, Shaw GM, Gaudilliere B, Wong RJ, Sylvester KG, Bonifacio SL, Aghaeepour N, Gibbs RS, Stevenson DK. Perinatal infection, inflammation, preterm birth, and brain injury: A review with proposals for future investigations. Exp Neurol 2022; 351:113988. [DOI: 10.1016/j.expneurol.2022.113988] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/06/2022] [Accepted: 01/13/2022] [Indexed: 11/26/2022]
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16
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Murthy GG, Prideaux MA, Armstrong M, Kenney HM, Latchney SE, Susiarjo M, Murphy SP. Characterization of the temporal, cell-specific and interferon-inducible patterns of indoleamine 2,3 dioxygenase 1 (IDO1) expression in the human placenta across gestation. Placenta 2021; 115:129-138. [PMID: 34619429 DOI: 10.1016/j.placenta.2021.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/09/2021] [Indexed: 01/01/2023]
Abstract
INTRODUCTION The human placenta performs multiple functions necessary for successful pregnancy, but the metabolic pathways and molecular mechanisms responsible for regulating placental development and functions remain incompletely understood. Catabolism of the essential amino acid tryptophan has numerous critical roles in normal physiology, including inflammation. The kynurenine pathway, which accounts for ∼90% of tryptophan breakdown, is mediated by indoleamine 2,3 dioxygenase 1 (IDO1) in the placenta. In pregnant mice, alterations of IDO1 activity or expression result in fetal resorption and a preeclampsia-like phenotype. Decreased IDO1 expression at the maternal-fetal interface has also been linked to preeclampsia, in utero growth restriction and recurrent miscarriage in humans. These collective observations suggest essential role(s) for IDO1 in maintaining healthy pregnancy. Despite these important roles, the precise temporal, cell-specific and inflammatory cytokine-mediated patterns of IDO1 expression in the human placenta have not been thoroughly characterized across gestation. METHODS Western blot and whole mount immunofluorescence (WMIF) were utilized to characterize and quantify basal and interferon (IFN)-inducible IDO1 expression in 1st trimester (7-13 weeks), 2nd trimester (14-22 weeks) and term (39-41 weeks) placental villi. RESULTS IDO1 expression is activated in the human placenta between the 13th and 14th weeks of pregnancy, increases through the 2nd trimester and remains elevated at term. Constitutive IDO1 expression is restricted to placental endothelial cells. Interestingly, different types of IFNs have distinct effects on IDO1 expression in the human placenta. DISCUSSION Our collective results are consistent with potential role(s) for IDO1 in the regulation of vascular functions in placental villi.
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Affiliation(s)
- Gayathri Guru Murthy
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Mallory A Prideaux
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Madison Armstrong
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - H Mark Kenney
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Sarah E Latchney
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Martha Susiarjo
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Shawn P Murphy
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA; Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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17
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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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18
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Notarangelo FM, Schwarcz R. A single prenatal lipopolysaccharide injection has acute, but not long-lasting, effects on cerebral kynurenine pathway metabolism in mice. Eur J Neurosci 2021; 54:5968-5981. [PMID: 34363411 DOI: 10.1111/ejn.15416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/26/2021] [Accepted: 08/03/2021] [Indexed: 11/28/2022]
Abstract
In rodents, a single injection of lipopolysaccharide (LPS) during gestation causes chemical and functional abnormalities in the offspring. These effects may involve changes in the kynurenine pathway (KP) of tryptophan degradation and may provide insights into the pathophysiology of psychiatric diseases. Using CD1 mice, we examined acute and long-term effects of prenatal LPS treatment on the levels of kynurenine and its neuroactive downstream products kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK) and quinolinic acid. To this end, LPS (100 μg/kg, i.p.) was administered on gestational day 15, and KP metabolites were measured 4 and 24 h later or in adulthood. After 4 h, kynurenine, KYNA and 3-HK levels were elevated in the fetal brain, 3-HK and KYNA levels were increased in the maternal plasma, and kynurenine was increased in the maternal brain, whereas no changes were seen in the placenta. These effects were less prominent after 24 h, and prenatal LPS did not affect the basal levels of KP metabolites in the forebrain of adult animals. In addition, a second LPS injection (1 mg/kg) in adulthood in the offspring of prenatally saline- and LPS-treated mice caused a similar elevation in 3-HK levels in both groups after 24 h, but the effect was significantly more pronounced in male mice. Thus, acute immune activation during pregnancy has only short-lasting effects on KP metabolism and does not cause cerebral KP metabolites to be disproportionally affected by a second immune challenge in adulthood. However, prenatal KYNA elevations still contribute to functional abnormalities in the offspring.
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Affiliation(s)
- Francesca M Notarangelo
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA
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19
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Kelly JR, Minuto C, Cryan JF, Clarke G, Dinan TG. The role of the gut microbiome in the development of schizophrenia. Schizophr Res 2021; 234:4-23. [PMID: 32336581 DOI: 10.1016/j.schres.2020.02.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
Schizophrenia is a heterogeneous neurodevelopmental disorder involving the convergence of a complex and dynamic bidirectional interaction of genetic expression and the accumulation of prenatal and postnatal environmental risk factors. The development of the neural circuitry underlying social, cognitive and emotional domains requires precise regulation from molecular signalling pathways, especially during critical periods or "windows", when the brain is particularly sensitive to the influence of environmental input signalling. Many of the brain regions involved, and the molecular substrates sub-serving these domains are responsive to life-long microbiota-gut-brain (MGB) axis signalling. This intricate microbial signalling system communicates with the brain via the vagus nerve, immune system, enteric nervous system, enteroendocrine signalling and production of microbial metabolites, such as short-chain fatty acids. Preclinical data has demonstrated that MGB axis signalling influences neurotransmission, neurogenesis, myelination, dendrite formation and blood brain barrier development, and modulates cognitive function and behaviour patterns, such as, social interaction, stress management and locomotor activity. Furthermore, preliminary clinical studies suggest altered gut microbiota profiles in schizophrenia. Unravelling MGB axis signalling in the context of an evolving dimensional framework in schizophrenia may provide a more complete understanding of the neurobiological architecture of this complex condition and offers the possibility of translational interventions.
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Affiliation(s)
- John R Kelly
- Department of Psychiatry, Trinity College Dublin, Ireland
| | - Chiara Minuto
- Department of Psychiatry and Neurobehavioral Science, University College Cork, Ireland
| | - John F Cryan
- APC Microbiome Ireland, University College Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - Gerard Clarke
- Department of Psychiatry and Neurobehavioral Science, University College Cork, Ireland; APC Microbiome Ireland, University College Cork, Ireland
| | - Timothy G Dinan
- Department of Psychiatry and Neurobehavioral Science, University College Cork, Ireland; APC Microbiome Ireland, University College Cork, Ireland.
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20
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Murakami Y, Imamura Y, Kasahara Y, Yoshida C, Momono Y, Fang K, Nishiyama T, Sakai D, Konishi Y. The Effects of Maternal Interleukin-17A on Social Behavior, Cognitive Function, and Depression-Like Behavior in Mice with Altered Kynurenine Metabolites. Int J Tryptophan Res 2021; 14:11786469211026639. [PMID: 34262289 PMCID: PMC8243115 DOI: 10.1177/11786469211026639] [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] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/31/2021] [Indexed: 01/03/2023] Open
Abstract
Viral infection and chronic maternal inflammation during pregnancy are correlated
with a higher prevalence of autism spectrum disorder (ASD). However, the
pathoetiology of ASD is not fully understood; moreover, the key molecules that
can cross the placenta following maternal inflammation and contribute to the
development of ASD have not been identified. Recently, the pro-inflammatory
cytokine, interleukin-17A (IL-17A) was identified as a potential mediator of
these effects. To investigate the impact of maternal IL-17A on offspring,
C57BL/6J dams were injected with IL-17A-expressing plasmids via
the tail vein on embryonic day 12.5 (E12.5), and maternal IL-17A was expressed
continuously throughout pregnancy. By adulthood, IL-17A-injected offspring
exhibited behavioral abnormalities, including social and cognitive defects.
Additionally, maternal IL-17A promoted metabolism of the essential amino acid
tryptophan, which produces several neuroactive compounds and may affect fetal
neurodevelopment. We observed significantly increased levels of kynurenine in
maternal serum and fetal plasma. Thus, we investigated the effects of high
maternal concentration of kynurenine on offspring by continuously administering
mouse dams with kynurenine from E12.5 during gestation. Obviously, maternal
kynurenine administration rapidly increased kynurenine levels in the fetal
plasma and brain, pointing to the ability of kynurenine to cross the placenta
and change the KP metabolites which are affected as neuroactive compounds in the
fetal brain. Notably, the offspring of kynurenine-injected mice exhibited
behavioral abnormalities similar to those observed in offspring of
IL-17A-conditioned mice. Several tryptophan metabolites were significantly
altered in the prefrontal cortex of the IL-17A-conditioned and
kynurenine-injected adult mice, but not in the hippocampus. Even though we
cannot exclude the possibility or other molecules being related to ASD
pathogenesis and the presence of a much lower degree of pathway activation, our
results suggest that increased kynurenine following maternal inflammation may be
a key factor in changing the balance of KP metabolites in fetal brain during
neuronal development and represents a therapeutic target for
inflammation-induced ASD-like phenotypes.
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Affiliation(s)
- Yuki Murakami
- Department of Hygiene and Public Health, Kansai Medical University, Osaka, Japan
| | - Yukio Imamura
- Organization for Research Initiatives and Development, Doshisha University, Kyoto, Japan.,Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshiyuki Kasahara
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Chihiro Yoshida
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Yuta Momono
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Ke Fang
- Department of Hygiene and Public Health, Kansai Medical University, Osaka, Japan
| | - Toshimasa Nishiyama
- Department of Hygiene and Public Health, Kansai Medical University, Osaka, Japan
| | - Daisuke Sakai
- Department of Biology, Kanazawa Medical University, Ishikawa, Japan
| | - Yukuo Konishi
- Center for Baby Science, Doshisha University, Kyoto, Japan.,Healthcare and Medical Data Multi-level Integration Platform Group, RIKEN Medical Sciences Innovation Hub Program, Kanagawa, Japan
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21
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Rentschler KM, Baratta AM, Ditty AL, Wagner NTJ, Wright CJ, Milosavljevic S, Mong JA, Pocivavsek A. Prenatal Kynurenine Elevation Elicits Sex-Dependent Changes in Sleep and Arousal During Adulthood: Implications for Psychotic Disorders. Schizophr Bull 2021; 47:1320-1330. [PMID: 33823027 PMCID: PMC8379538 DOI: 10.1093/schbul/sbab029] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dysregulation of the kynurenine pathway (KP) of tryptophan catabolism has been implicated in psychotic disorders, including schizophrenia and bipolar disorder. Kynurenic acid (KYNA) is a KP metabolite synthesized by kynurenine aminotransferases (KATs) from its biological precursor kynurenine and acts as an endogenous antagonist of N-methyl-D-aspartate and α7-nicotinic acetylcholine receptors. Elevated KYNA levels found in postmortem brain tissue and cerebrospinal fluid of patients are hypothesized to play a key role in the etiology of cognitive symptoms observed in psychotic disorders. Sleep plays an important role in memory consolidation, and sleep disturbances are common among patients. Yet, little is known about the effect of altered KP metabolism on sleep-wake behavior. We presently utilized a well-established experimental paradigm of embryonic kynurenine (EKyn) exposure wherein pregnant dams are fed a diet laced with kynurenine the last week of gestation and hypothesized disrupted sleep-wake behavior in adult offspring. We examined sleep behavior in adult male and female offspring using electroencephalogram and electromyogram telemetry and determined sex differences in sleep and arousal in EKyn offspring. EKyn males displayed reduced rapid eye movement sleep, while female EKyn offspring were hyperaroused compared to controls. We determined that EKyn males maintain elevated brain KYNA levels, while KYNA levels were unchanged in EKyn females, yet the activity levels of KAT I and KAT II were reduced. Our findings indicate that elevated prenatal kynurenine exposure elicits sex-specific changes in sleep-wake behavior, arousal, and KP metabolism.
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Affiliation(s)
- Katherine M Rentschler
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | | | - Audrey L Ditty
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Nathan T J Wagner
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Courtney J Wright
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Snezana Milosavljevic
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Jessica A Mong
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ana Pocivavsek
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA,To whom correspondence should be addressed; tel: (803) 216–3509, fax: 803-216-3538, e-mail:
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22
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Noorbakhsh A, Hosseininezhadian Koushki E, Farshadfar C, Ardalan N. Designing a natural inhibitor against human kynurenine aminotransferase type II and a comparison with PF-04859989: a computational effort against schizophrenia. J Biomol Struct Dyn 2021; 40:7038-7051. [PMID: 33645449 DOI: 10.1080/07391102.2021.1893817] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Kynurenine aminotransferase II (KATII) enzyme has an essential role in L-kynurenine transmission to kynurenic acid (KYNA). High concentration of kynurenic acid associates with schizophrenia and some neurocognitive disorders. Decreasing KYNA production via inhibiting KATII would be an effective method for treating and understanding the related central nervous system (CNS) diseases. This study aimed to discover a potent inhibitor against human KATII (hKATII) in comparison with PF-04859989. We utilized the computational methods of molecular dynamics, virtual screening, docking, and binding free-energy calculations. Initially, the 58722 compounds from three drug libraries, including IBS library, DrugBank library, and Analyticon library, were obtained. At the next stage, these sets of compounds were screened by AutoDock Vina software, and a potent inhibitor (ZINC35466084) was selected. Following the screening, molecular dynamics simulations for both ZINC35466084 and PF-04859989 were performed by GROMACS software. MM-PBSA analysis showed that the amount of binding free energy for ZINC35466084 (-61.26 KJ mol-1) is more potent than PF-04859989 (-43.14 KJ mol-1). Furthermore, the ADME analysis results revealed that the pharmacokinetic parameters of ZINC35466084 are acceptable for human use. Eventually, our data demonstrated that ZINC35466084 is suitable for hKATII inhibition, and it is an appropriate candidate for further studies in the laboratory. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Akbar Noorbakhsh
- Department of Biochemistry, Science and Research Branch, Islamic Azad University, Sanandaj, Iran
| | - Elnaz Hosseininezhadian Koushki
- Nano Drug Delivery Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Chiako Farshadfar
- Department of Biochemistry, Science and Research Branch, Islamic Azad University, Sanandaj, Iran
| | - Noeman Ardalan
- Department of Microbiology, Science and Research Branch, Islamic Azad University, Tehran, Iran
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23
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Subchronic N-acetylcysteine Treatment Decreases Brain Kynurenic Acid Levels and Improves Cognitive Performance in Mice. Antioxidants (Basel) 2021; 10:antiox10020147. [PMID: 33498402 PMCID: PMC7909398 DOI: 10.3390/antiox10020147] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/06/2021] [Accepted: 01/16/2021] [Indexed: 11/17/2022] Open
Abstract
The tryptophan (Trp) metabolite kynurenic acid (KYNA) is an α7-nicotinic and N-methyl-d-aspartate receptor antagonist. Elevated brain KYNA levels are commonly seen in psychiatric disorders and neurodegenerative diseases and may be related to cognitive impairments. Recently, we showed that N-acetylcysteine (NAC) inhibits kynurenine aminotransferase II (KAT II), KYNA's key biosynthetic enzyme, and reduces KYNA neosynthesis in rats in vivo. In this study, we examined if repeated systemic administration of NAC influences brain KYNA and cognitive performance in mice. Animals received NAC (100 mg/kg, i.p.) daily for 7 days. Redox markers, KYNA levels, and KAT II activity were determined in the brain. We also assessed the effect of repeated NAC treatment on Trp catabolism using brain tissue slices ex vivo. Finally, learning and memory was evaluated with and without an acute challenge with KYNA's bioprecursor L-kynurenine (Kyn; 100 mg/kg). Subchronic NAC administration protected against an acute pro-oxidant challenge, decreased KYNA levels, and lowered KAT II activity and improved memory both under basal conditions and after acute Kyn treatment. In tissue slices from these mice, KYNA neosynthesis from Trp or Kyn was reduced. Together, our data indicate that prolonged treatment with NAC may enhance memory at least in part by reducing brain KYNA levels.
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24
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Schakenraad L, Van Es MJ, Meerman JJ, Van den Broek PHH, Van Hove H, Van Drongelen J, Eliesen GAM, Russel FGM, Greupink R. Transfer of uremic solutes across the human term placenta: An ex vivo study in the dual-side perfused cotyledon. Placenta 2021; 104:220-231. [PMID: 33429119 DOI: 10.1016/j.placenta.2020.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 10/25/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022]
Abstract
INTRODUCTION An increasing number of women becomes pregnant while suffering from chronic kidney disease (CKD). As a result of decreased renal function, uremic solutes circulate at high levels in the maternal circulation. This study aimed to acquire more knowledge about the placental transfer of uremic solutes across the human placenta. METHODS Placental transfer was studied in healthy term placentas, via the ex vivo dual-side human cotyledon perfusion technique (closed-closed set-up for both maternal and fetal circulations). Uremic solute concentrations in maternal and fetal perfusates were measured via LC-MS/MS over 180 min of perfusion. RESULTS We found that the studied compounds demonstrated different degrees of placental transfer. Fetal-to-maternal perfusate ratios at t = 180 min were for anthranilic acid 1.00 ± 0.02, indole-3-acetic acid 0.47 ± 0.08, hippuric acid 0.36 ± 0.18, l-arabinitol 0.33 ± 0.04, indoxyl sulfate 0.33 ± 0.11, neopterin 0.28 ± 0.14 and kynurenic acid 0.13 ± 0.03. All uremic solutes studied also emerged in the perfusates when cotyledons were perfused in the absence of uremic solute concentrations added to the maternal reservoir. For kynurenin these concentrations were so high, it complicated the calculation of a transfer ratio for the exogenously administered compound. DISCUSSION After 180 min of exposure the extent of placental transfer differs substantially for the solutes studied, reflecting different transfer rates. Future studies should investigate to what extent specific uremic solutes reach the fetal circulation in vivo and how they may interfere with organ function and development of the unborn child.
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Affiliation(s)
- L Schakenraad
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - M J Van Es
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - J J Meerman
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - P H H Van den Broek
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - H Van Hove
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - J Van Drongelen
- Department of Obstetrics and Gynecology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - G A M Eliesen
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - F G M Russel
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - R Greupink
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
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25
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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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26
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Sorgdrager F, van Der Ley CP, van Faassen M, Calus E, Nollen EA, Kema IP, van Dam D, De Deyn PP. The Effect of Tryptophan 2,3-Dioxygenase Inhibition on Kynurenine Metabolism and Cognitive Function in the APP23 Mouse Model of Alzheimer's Disease. Int J Tryptophan Res 2020; 13:1178646920972657. [PMID: 33447045 PMCID: PMC7780178 DOI: 10.1177/1178646920972657] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 10/18/2020] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is associated with progressive endogenous neurotoxicity and hampered inflammatory regulation. The kynurenine (Kyn) pathway, which is controlled by tryptophan 2,3-dioxygenase (TDO), produces neuroactive and anti-inflammatory metabolites. Age-related Kyn pathway activation might contribute to AD pathology in humans, and inhibition of TDO was found to reduce AD-related cellular toxicity and behavioral deficits in animal models. To further explore the effect of aging on the Kyn pathway in the context of AD, we analyzed Kyn metabolite profiles in serum and brain tissue of the APP23 amyloidosis mouse model. We found that aging had genotype-independent effects on Kyn metabolite profiles in serum, cortex, hippocampus and cerebellum, whereas serum concentrations of many Kyn metabolites were reduced in APP23 mice. Next, to further establish the role of TDO in AD-related behavioral deficits, we investigated the effect of long-term pharmacological TDO inhibition on cognitive performance in APP23 mice. Our results indicated that TDO inhibition reversed recognition memory deficits without producing measurable changes in cerebral Kyn metabolites. TDO inhibition did not affect spatial learning and memory or anxiety-related behavior. These data indicate that age-related Kyn pathway activation is not specific for humans and could represent a cross-species phenotype of aging. These data warrant further investigation on the role of peripheral Kyn pathway disturbances and cerebral TDO activity in AD pathophysiology.
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Affiliation(s)
- Fjh Sorgdrager
- Laboratory of Neurochemistry and Behavior, Department of Biomedical Sciences, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands.,Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - C P van Der Ley
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M van Faassen
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - E Calus
- Laboratory of Neurochemistry and Behavior, Department of Biomedical Sciences, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - E A Nollen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - I P Kema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - D van Dam
- Laboratory of Neurochemistry and Behavior, Department of Biomedical Sciences, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - P P De Deyn
- Laboratory of Neurochemistry and Behavior, Department of Biomedical Sciences, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands.,Department of Neurology, Memory Clinic of Hospital Network Antwerp (ZNA) Middelheim and Hoge Beuken, Antwerp, Belgium
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27
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Jorratt P, Hoschl C, Ovsepian SV. Endogenous antagonists of N-methyl-d-aspartate receptor in schizophrenia. Alzheimers Dement 2020; 17:888-905. [PMID: 33336545 DOI: 10.1002/alz.12244] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/24/2020] [Indexed: 12/28/2022]
Abstract
Schizophrenia is a chronic neuropsychiatric brain disorder that has devastating personal impact and rising healthcare costs. Dysregulation of glutamatergic neurotransmission has been implicated in the pathobiology of the disease, attributed largely to the hypofunction of the N-methyl-d-aspartate (NMDA) receptor. Currently, there is a major gap in mechanistic analysis as to how endogenous modulators of the NMDA receptors contribute to the onset and progression of the disease. We present a systematic review of the neurobiology and the role of endogenous NMDA receptor antagonists in animal models of schizophrenia, and in patients. We discuss their neurochemical origin, release from neurons and glia with action mechanisms, and functional effects, which might contribute toward the impairment of neuronal processes underlying this complex pathological state. We consider clinical evidence suggesting dysregulations of endogenous NMDA receptor in schizophrenia, and highlight the pressing need in future studies and emerging directions, to restore the NMDA receptor functions for therapeutic benefits.
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Affiliation(s)
- Pascal Jorratt
- Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Cyril Hoschl
- Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Saak V Ovsepian
- Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
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28
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Candidate metabolic biomarkers for schizophrenia in CNS and periphery: Do any possible associations exist? Schizophr Res 2020; 226:95-110. [PMID: 30935700 DOI: 10.1016/j.schres.2019.03.009] [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: 10/09/2018] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
Due to the limitations of analytical techniques and the complicity of schizophrenia, nowadays it is still a challenge to diagnose and stratify schizophrenia patients accurately. Many attempts have been made to identify and validate available biomarkers for schizophrenia from CSF and/or peripheral blood in clinical studies with consideration to disease stages, antipsychotic effects and even gender differences. However, conflicting results handicap the validation and application of biomarkers for schizophrenia. In view of availability and feasibility, peripheral biomarkers have superior advantages over biomarkers in CNS. Meanwhile, schizophrenia is considered to be a devastating neuropsychiatric disease mainly taking place in CNS featured by widespread defects in multiple metabolic pathways whose dynamic interactions, until recently, have been difficult to difficult to investigate. Evidence for these alterations has been collected piecemeal, limiting the potential to inform our understanding of the interactions among relevant biochemical pathways. Taken these points together, it will be interesting to investigate possible associations of biomarkers between CNS and periphery. Numerous studies have suggested putative correlations within peripheral and CNS systems especially for dopaminergic and glutamatergic metabolic biomarkers. In addition, it has been demonstrated that blood concentrations of BDNF protein can also reflect its changes in the nervous system. In turn, BDNF also interacts with glutamatergic, dopaminergic and serotonergic systems. Therefore, this review will summarize metabolic biomarkers identified both in the CNS (brain tissues and CSF) and peripheral blood. Further, more attentions will be paid to discussing possible physical and functional associations between CNS and periphery, especially with respect to BDNF.
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29
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Skonieczna-Żydecka K, Jakubczyk K, Maciejewska-Markiewicz D, Janda K, Kaźmierczak-Siedlecka K, Kaczmarczyk M, Łoniewski I, Marlicz W. Gut Biofactory-Neurocompetent Metabolites within the Gastrointestinal Tract. A Scoping Review. Nutrients 2020; 12:E3369. [PMID: 33139656 PMCID: PMC7693392 DOI: 10.3390/nu12113369] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
The gut microbiota have gained much scientific attention recently. Apart from unravelling the taxonomic data, we should understand how the altered microbiota structure corresponds to functions of this complex ecosystem. The metabolites of intestinal microorganisms, especially bacteria, exert pleiotropic effects on the human organism and contribute to the host systemic balance. These molecules play key roles in regulating immune and metabolic processes. A subset of them affect the gut brain axis signaling and balance the mental wellbeing. Neurotransmitters, short chain fatty acids, tryptophan catabolites, bile acids and phosphatidylcholine, choline, serotonin, and L-carnitine metabolites possess high neuroactive potential. A scoping literature search in PubMed/Embase was conducted up until 20 June 2020, using three major search terms "microbiota metabolites" AND "gut brain axis" AND "mental health". This review aimed to enhance our knowledge regarding the gut microbiota functional capacity, and support current and future attempts to create new compounds for future clinical interventions.
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Affiliation(s)
- Karolina Skonieczna-Żydecka
- Department of Human Nutrition and Metabolomics, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland; (K.S.-Ż.); (K.J.); (D.M.-M.); (K.J.)
| | - Karolina Jakubczyk
- Department of Surgical Oncology, Medical University of Gdansk, Smoluchowskiego 17, 80-214 Gdańsk, Poland;
| | - Dominika Maciejewska-Markiewicz
- Department of Human Nutrition and Metabolomics, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland; (K.S.-Ż.); (K.J.); (D.M.-M.); (K.J.)
| | - Katarzyna Janda
- Department of Human Nutrition and Metabolomics, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland; (K.S.-Ż.); (K.J.); (D.M.-M.); (K.J.)
| | | | - Mariusz Kaczmarczyk
- Department of Clinical and Molecular Biochemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland;
| | - Igor Łoniewski
- Department of Human Nutrition and Metabolomics, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland; (K.S.-Ż.); (K.J.); (D.M.-M.); (K.J.)
| | - Wojciech Marlicz
- Department of Gastroenterology, Pomeranian Medical University, 71-252 Szczecin, Poland
- The Centre for Digestive Diseases Endoklinika, 70-535 Szczecin, Poland
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30
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Abad C, Karahoda R, Kastner P, Portillo R, Horackova H, Kucera R, Nachtigal P, Staud F. Profiling of Tryptophan Metabolic Pathways in the Rat Fetoplacental Unit During Gestation. Int J Mol Sci 2020; 21:ijms21207578. [PMID: 33066440 PMCID: PMC7589826 DOI: 10.3390/ijms21207578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/11/2020] [Accepted: 10/11/2020] [Indexed: 01/11/2023] Open
Abstract
Placental homeostasis of tryptophan is essential for fetal development and programming. The two main metabolic pathways (serotonin and kynurenine) produce bioactive metabolites with immunosuppressive, neurotoxic, or neuroprotective properties and their concentrations in the fetoplacental unit must be tightly regulated throughout gestation. Here, we investigated the expression/function of key enzymes/transporters involved in tryptophan pathways during mid-to-late gestation in rat placenta and fetal organs. Quantitative PCR and heatmap analysis revealed the differential expression of several genes involved in serotonin and kynurenine pathways. To identify the flux of substrates through these pathways, Droplet Digital PCR, western blot, and functional analyses were carried out for the rate-limiting enzymes and transporters. Our findings show that placental tryptophan metabolism to serotonin is crucial in mid-gestation, with a subsequent switch to fetal serotonin synthesis. Concurrently, at term, the close interplay between transporters and metabolizing enzymes of both placenta and fetal organs orchestrates serotonin homeostasis and prevents hyper/hypo-serotonemia. On the other hand, the placental production of kynurenine increases during pregnancy, with a low contribution of fetal organs throughout gestation. Any external insult to this tightly regulated harmony of transporters and enzymes within the fetoplacental unit may affect optimal in utero conditions and have a negative impact on fetal programming.
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Affiliation(s)
- Cilia Abad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (C.A.); (R.K.); (R.P.); (H.H.)
| | - Rona Karahoda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (C.A.); (R.K.); (R.P.); (H.H.)
| | - Petr Kastner
- Department of Pharmaceutical Chemistry and Pharmaceutical Analysis, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (P.K.); (R.K.)
| | - Ramon Portillo
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (C.A.); (R.K.); (R.P.); (H.H.)
| | - Hana Horackova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (C.A.); (R.K.); (R.P.); (H.H.)
| | - Radim Kucera
- Department of Pharmaceutical Chemistry and Pharmaceutical Analysis, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (P.K.); (R.K.)
| | - Petr Nachtigal
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic;
| | - Frantisek Staud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Akademika Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (C.A.); (R.K.); (R.P.); (H.H.)
- Correspondence: ; Tel.: +420-495-067-407
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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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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: 62] [Impact Index Per Article: 15.5] [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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Evrensel A, Ünsalver BÖ, Ceylan ME. Immune-Kynurenine Pathways and the Gut Microbiota-Brain Axis in Anxiety Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1191:155-167. [PMID: 32002928 DOI: 10.1007/978-981-32-9705-0_10] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Anxiety disorders are a complex set of illnesses in which genetic factors, particularly stress, play a role in the etiopathogenesis. In recent years, inflammation and intestinal microbiota have also been included in this complex network of relationships. The functions associated with tryptophan catabolism and serotonin biosynthesis have long been associated with anxiety disorders. Tryptophan catabolism progresses toward the path of the kynurenine in the presence of stress and inflammation. The catabolism of kynurenine is a pathway in which many enzymes play a role and a large number of catabolites with neuroactive properties occur. The body's serotonin biosynthesis is primarily performed by enterochromaffin cells located in the intestines. A change in the intestinal microbiota composition (dysbiosis) directly affects the serotonin biosynthesis. Stress, unhealthy nutrition, and the use of antibiotics cause dysbiosis. In the light of this new perspective, the role of dysbiosis-induced inflammation and kynurenine pathway catabolites activated sequentially come into prominence in the etiopathogenesis of anxiety disorders.
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Affiliation(s)
- Alper Evrensel
- Department of Psychiatry, Uskudar University, Umraniye, Istanbul, Turkey.
| | - Barış Önen Ünsalver
- Vocational School of Health Services, Department of Medical Documentation and Secretariat, Uskudar University, Istanbul, Turkey
| | - Mehmet Emin Ceylan
- Departments of Psychology and Philosophy, Uskudar University, Istanbul, Turkey
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35
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Huang X, Ding W, Wu F, Zhou S, Deng S, Ning Y. Increased Plasma Kynurenic Acid Levels are Associated with Impaired Attention/Vigilance and Social Cognition in Patients with Schizophrenia. Neuropsychiatr Dis Treat 2020; 16:263-271. [PMID: 32158211 PMCID: PMC6986175 DOI: 10.2147/ndt.s239763] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 01/13/2020] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE Preclinical studies have reported that abnormal kynurenic acid (KYNA) may play a role in cognitive deficits. Schizophrenia (SCZ) is characterized by a wide range of cognitive deficits that may evolve from abnormal KYNA. This study aimed to explore the relationship between KYNA and cognitive impairment in SCZ, which has not yet been reported. METHODS We recruited 30 SCZ patients and 34 healthy controls, measured clinical symptoms by using the Positive and Negative Syndrome Scale and performed cognitive tests using the MATRICS Consensus Cognitive Battery (MCCB). Plasma levels of tryptophan, kynurenine, and KYNA were determined by high-performance liquid chromatography-tandem mass spectrometry. RESULTS We found that plasma KYNA levels were significantly higher in patients than in healthy controls (p=0.009). The cognitive performance of patients in the total MCCB scores and the scores of all subscales were significantly lower than those in healthy controls (all P < 0.01). Correlation analysis showed that KYNA levels were negatively correlated with attention/vigilance (r=-0.457, p=0.019) and social cognition (r=-0.481, p=0.013) only in SCZ patients. CONCLUSION Our results indicate that elevated plasma KYNA levels may serve as a biomarker of cognitive impairment in SCZ patients.
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Affiliation(s)
- Xingbing Huang
- First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.,The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, People's Republic of China
| | - Wenhua Ding
- The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, People's Republic of China
| | - Fengchun Wu
- The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, People's Republic of China
| | - Sumiao Zhou
- The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, People's Republic of China
| | - Shuhua Deng
- The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, People's Republic of China
| | - Yuping Ning
- First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.,The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong, People's Republic of China.,Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, Guangdong, People's Republic of China
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36
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Ogbechi J, Clanchy FI, Huang YS, Topping LM, Stone TW, Williams RO. IDO activation, inflammation and musculoskeletal disease. Exp Gerontol 2019; 131:110820. [PMID: 31884118 DOI: 10.1016/j.exger.2019.110820] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 12/11/2022]
Abstract
The IDO/kynurenine pathway is now established as a major regulator of immune system function. The initial enzyme, indoleamine 2,3-dioxygenase (IDO1) is induced by IFNγ, while tryptophan-2,3-dioxygenase (TDO) is induced by corticosteroids. The pathway is therefore positioned to mediate the effects of systemic inflammation or stress-induced steroids on tissue function and its expression increases with age. Disorders of the musculoskeletal system are a common feature of ageing and many of these conditions are characterized by an inflammatory state. In inflammatory arthritis and related disorders, kynurenine protects against the development of disease, while inhibition or deletion of IDO1 increases its severity. The long-term regulation of autoimmune disorders may be influenced by the epigenetic modulation of kynurenine pathway genes, with recent data suggesting that methylation of IDO may be involved. Osteoporosis is also associated with abnormalities of the kynurenine pathway, reflected in an inversion of the ratio between blood levels of the metabolites anthranilic acid and 3-hydroxy-anthranilic acid. This review discusses evidence to date on the role of the IDO/kynurenine pathway and the highly prevalent age-related disorders of osteoporosis and rheumatoid arthritis and identifies key areas that require further research.
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Affiliation(s)
- Joy Ogbechi
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford OX3 7FY, UK
| | - Felix I Clanchy
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford OX3 7FY, UK
| | - Yi-Shu Huang
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford OX3 7FY, UK
| | - Louise M Topping
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford OX3 7FY, UK
| | - Trevor W Stone
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford OX3 7FY, UK
| | - Richard O Williams
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford OX3 7FY, UK.
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37
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Baratta AM, Kanyuch NR, Cole CA, Valafar H, Deslauriers J, Pocivavsek A. Acute sleep deprivation during pregnancy in rats: Rapid elevation of placental and fetal inflammation and kynurenic acid. Neurobiol Stress 2019; 12:100204. [PMID: 32258253 PMCID: PMC7109515 DOI: 10.1016/j.ynstr.2019.100204] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 11/27/2019] [Accepted: 12/11/2019] [Indexed: 01/19/2023] Open
Abstract
The kynurenine pathway (KP) is the dominant pathway for tryptophan degradation in the mammalian body and emerging evidence suggests that acute episodes of sleep deprivation (SD) disrupt tryptophan metabolism via the KP. Increases in the neuroactive KP metabolite kynurenic acid (KYNA) during pregnancy may lead to a higher risk for disrupted neurodevelopment in the offspring. As pregnancy is a critical period during which several factors, including sleep disruptions, could disrupt the fetal environment, we presently explored the relationship between maternal SD and KP metabolism and immune pathways in maternal, placenta, and fetal tissues. Pregnant Wistar rat dams were sleep deprived by gentle handling for 5 h from zeitgeber time (ZT) 0 to ZT 5. Experimental cohorts included: i) controls, ii) one session of SD on embryonic day (ED) 18 or iii) three sessions of SD occurring daily on ED 16, ED 17 and ED 18. Maternal (plasma, brain), placental and fetal (plasma, brain) tissues were collected immediately after the last session of SD or after 24 h of recovery from SD. Respective controls were euthanized at ZT 5 on ED 18 or ED 19. Maternal plasma corticosterone and fetal brain KYNA were significantly elevated only after one session of SD on ED 18. Importantly, maternal plasma corticosterone levels correlated significantly with fetal brain KYNA levels. In addition, placental levels of the proinflammatory cytokines interleukin-1β (IL-1β) and interleukin-6 (IL-6) were increased following maternal SD, suggesting a relationship between placental immune response to SD and fetal brain KYNA accumulation. Collectively, our results demonstrate that sleep loss during the last week of gestation can adversely impact maternal stress, placental immune function, and fetal brain KYNA levels. We introduce KYNA as a novel molecular target influenced by sleep loss during pregnancy. Prenatal sleep deprivation influences kynurenine pathway metabolism in utero. Fetal brain kynurenic acid (KYNA) is elevated after maternal sleep deprivation. Maternal plasma corticosterone is increased after sleep deprivation. Prenatal sleep deprivation induces placental and fetal brain cytokines. These data support an interplay with stress, in utero inflammation, and KYNA.
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Affiliation(s)
- Annalisa M Baratta
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nickole R Kanyuch
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Casey A Cole
- College of Engineering and Computing, University of South Carolina, Columba, South Carolina, USA
| | - Homayoun Valafar
- College of Engineering and Computing, University of South Carolina, Columba, South Carolina, USA
| | - Jessica Deslauriers
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.,Center of Excellence for Stress and Mental Health, Veterans Affairs Hospital, La Jolla, CA, 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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38
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Tryptophan metabolism as a common therapeutic target in cancer, neurodegeneration and beyond. Nat Rev Drug Discov 2019; 18:379-401. [PMID: 30760888 DOI: 10.1038/s41573-019-0016-5] [Citation(s) in RCA: 785] [Impact Index Per Article: 157.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
L-Tryptophan (Trp) metabolism through the kynurenine pathway (KP) is involved in the regulation of immunity, neuronal function and intestinal homeostasis. Imbalances in Trp metabolism in disorders ranging from cancer to neurodegenerative disease have stimulated interest in therapeutically targeting the KP, particularly the main rate-limiting enzymes indoleamine-2,3-dioxygenase 1 (IDO1), IDO2 and tryptophan-2,3-dioxygenase (TDO) as well as kynurenine monooxygenase (KMO). However, although small-molecule IDO1 inhibitors showed promise in early-stage cancer immunotherapy clinical trials, a phase III trial was negative. This Review summarizes the physiological and pathophysiological roles of Trp metabolism, highlighting the vast opportunities and challenges for drug development in multiple diseases.
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39
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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: 15] [Impact Index Per Article: 3.0] [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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40
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Notarangelo FM, Beggiato S, Schwarcz R. Assessment of Prenatal Kynurenine Metabolism Using Tissue Slices: Focus on the Neosynthesis of Kynurenic Acid in Mice. Dev Neurosci 2019; 41:102-111. [PMID: 31117076 DOI: 10.1159/000499736] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/19/2019] [Indexed: 01/17/2023] Open
Abstract
Several lines of evidence support the hypothesis that abnormally elevated brain levels of kynurenic acid (KYNA), a metabolite of the kynurenine pathway (KP) of tryptophan degradation, play a pathophysiologically significant role in schizophrenia and other major neurodevelopmental disorders. Studies in experimental animal models suggest that KP impairments in these diseases may originate already in utero since prenatal administration of KYNA's bioprecursor, kynurenine, leads to biochemical and structural abnormalities as well as distinct cognitive impairments in adulthood. As KP metabolism during pregnancy is still insufficiently understood, we designed this study to examine the de novo synthesis of KYNA and 3-hydroxykynurenine (3-HK), an alternative biologically active product of kynurenine degradation, in tissue slices obtained from pregnant mice on gestational day (GD) 18. Fetal brain and liver, placenta, and maternal brain and liver were collected, and the tissues were incubated in vitroin the absence or presence of micromolar concentrations of kynurenine. KYNA and 3-HK were measured in the extracellular milieu. Basal and newly produced KYNA was detected in all cases. As KYNA formation exceeded 3-HK production by 2-3 orders of magnitude in the placenta and maternal brain, and as very little 3-HK neosynthesis was detectable in fetal brain tissue, detailed follow-up experiments focused on KYNA only. The fetal brain produced 3-4 times more KYNA than the maternal brain and placenta, though less than the maternal and fetal liver. No significant differences were observed when using tissues obtained on GD 14 and GD 18. Pharmacological inhibition of KYNA's main biosynthetic enzymes, kynurenine aminotransferase (KAT) I and KAT II, revealed qualitative and quantitative differences between the tissues, with a preferential role of KAT I in the fetal and maternal brain and of KAT II in the fetal and maternal liver. Findings using tissue slices from KAT II knockout mice confirmed these conclusions. Together, these results clarify the dynamics of KP metabolism during pregnancy and provide the basis for the conceptualization of interventions aimed at manipulating cerebral KP function in the prenatal period.
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Affiliation(s)
- Francesca M Notarangelo
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA,
| | - Sarah Beggiato
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA
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41
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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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42
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Xu K, Bai M, Bin P, Duan Y, Wu X, Liu H, Yin Y. Negative effects on newborn piglets caused by excess dietary tryptophan in the morning in sows. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2019; 99:3005-3016. [PMID: 30478950 DOI: 10.1002/jsfa.9514] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND This study investigated the effect of dynamic feeding models of dietary tryptophan on sows' performance during late pregnancy. RESULTS The average piglet birth weight and live farrowing rate from sows consuming a high-low tryptophan diet (0.39% Trp in the morning and 0.13% Trp in the afternoon) were decreased compared with those fed a 2×tryptophan diet (0.26% Trp in the morning and afternoon). Compared with the 2×tryptophan group, sow serum kynurenic acid and the newborn liver n-6:n-3 polyunsaturated fatty acid ratio were significantly higher, and sow serum taurine and newborn serum taurine, phosphoserine, cysteine and proline were lower in the high-low tryptophan diet group. Eighty-eight genes were differentially expressed in newborn piglets' livers between the 2×tryptophan and high-low groups. Genes related to cytotoxic effector regulation (major histocompatibility complex class I proteins), NADH oxidation, reactive oxygen species (ROS) metabolism and tissue development were differentially expressed between these two groups. CONCLUSION Together, the results provide information on new biomarkers in serum or liver and provide novel insights into variations in the fetal liver during exogenous stimulus response and biological processes of ROS metabolism in fetuses during late pregnancy caused by a single excessive tryptophan ingestion daily in the morning. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Kang Xu
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Miaomiao Bai
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha, China
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Peng Bin
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Yehui Duan
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Xin Wu
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Hongnan Liu
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha, China
- Hunan Co-Innovation Center of Animal Production Safety, CICAPS, Changsha, China
| | - Yulong Yin
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha, China
- College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Kondarl Agro-pastoral Technology Co., Ltd., Dongguan, China
- Academician Workstation of Changsha Medical University, Changsha, China
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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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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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Groer M, Fuchs D, Duffy A, Louis-Jacques A, D’Agata A, Postolache TT. Associations Among Obesity, Inflammation, and Tryptophan Catabolism in Pregnancy. Biol Res Nurs 2018; 20:284-291. [PMID: 29141444 PMCID: PMC6346309 DOI: 10.1177/1099800417738363] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To evaluate relationships among obesity in pregnancy and plasma levels of tryptophan (TRP) and kynurenine (KYN), inflammatory markers, and depressed mood. METHODS Pregnant women ( N = 374) were enrolled, and data were collected at a mean gestation of 20 weeks in this cross-sectional study. Plasma was analyzed for TRP, KYN, neopterin, and nitrite levels. Women completed demographic and mood scales. RESULTS There was a statistically significant inverse correlation between body mass index (BMI) and TRP and positive correlations between BMI and KYN and the kynurenine/tryptophan (KYN/TRP) ratio. Neopterin was correlated with KYN/TRP, suggesting that the indoleamine 2,3-dioxygenase-1 (IDO-1) enzyme was activated. The correlations of neopterin and nitrite with BMI were too small to be clinically meaningful but may provide mechanistic insight. There was a correlation between depressed mood and nitrite levels. Depressed mood was also associated with lower TRP levels. When the sample was divided into pregnant women with or without obesity, TRP was significantly lower and the KYN/TRP ratio was significantly higher in the women with obesity. CONCLUSION The pro-inflammatory state of obesity in pregnancy may drive activation of IDO-1, resulting in diversion of TRP away from serotonin and melatonin production and toward KYN metabolites. This alteration could contribute to depression, impaired sleep, increased production of excitotoxic neurotransmitters, and reinforcement of a pro-inflammatory state in pregnancy.
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Affiliation(s)
- Maureen Groer
- Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- University of South Florida College of Nursing, Tampa, FL, USA
| | - Dietmar Fuchs
- Division of Biological Chemistry, Innsbruck Medical University, Innsbruck, Austria
| | - Allyson Duffy
- University of South Florida College of Nursing, Tampa, FL, USA
| | - Adetola Louis-Jacques
- Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- University of South Florida College of Nursing, Tampa, FL, USA
| | - Amy D’Agata
- University of South Florida College of Nursing, Tampa, FL, USA
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Hahn B, Reneski CH, Pocivavsek A, Schwarcz R. Prenatal kynurenine treatment in rats causes schizophrenia-like broad monitoring deficits in adulthood. Psychopharmacology (Berl) 2018; 235:651-661. [PMID: 29128872 PMCID: PMC5823752 DOI: 10.1007/s00213-017-4780-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/01/2017] [Indexed: 12/12/2022]
Abstract
RATIONALE Elevated brain kynurenic acid (KYNA) levels are implicated in the pathology and neurodevelopmental pathogenesis of schizophrenia. In rats, embryonic treatment with kynurenine (EKyn) causes elevated brain KYNA levels in adulthood and cognitive deficits reminiscent of schizophrenia. OBJECTIVES Growing evidence suggests that people with schizophrenia have a narrowed attentional focus, and we aimed at establishing whether these abnormalities may be related to KYNA dysregulation. METHODS To test whether EKyn rats display broad monitoring deficits, kynurenine was added to the chow of pregnant Wistar dams on embryonic days 15-22. As adults, 20 EKyn and 20 control rats were trained to stable performance on the five-choice serial reaction time task, requiring the localization of 1-s light stimuli presented randomly across five apertures horizontally arranged along a curved wall, equating the locomotor demands of reaching each hole. RESULTS EKyn rats displayed elevated omission errors and reduced anticipatory responses relative to control rats, indicative of a lower response rate, and showed reduced locomotor activity. The ability to spread attention broadly was measured by parsing performance by stimulus location. Both groups displayed poorer stimulus detection with greater target location eccentricity, but this effect was significantly more pronounced in the EKyn group. Specifically, the groups differed in the spatial distribution of correct but not incorrect responses. This pattern cannot be explained by differences in response rate and is indicative of a narrowed attentional focus. CONCLUSIONS The findings suggest a potential etiology of broad monitoring deficits in schizophrenia, which may constitute a core cognitive deficit.
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Affiliation(s)
- Britta Hahn
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD, 21228, USA.
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47
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Goeden N, Notarangelo FM, Pocivavsek A, Beggiato S, Bonnin A, Schwarcz R. Prenatal Dynamics of Kynurenine Pathway Metabolism in Mice: Focus on Kynurenic Acid. Dev Neurosci 2017; 39:519-528. [PMID: 29080891 DOI: 10.1159/000481168] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/31/2017] [Indexed: 01/09/2023] Open
Abstract
The kynurenine pathway (KP), the major catabolic route of tryptophan in mammals, contains several neuroactive metabolites, including kynurenic acid (KYNA) and 3-hydroxykynurenine (3-HK). KP metabolism, and especially the fate of KYNA, during pregnancy is poorly understood, yet it may play a significant role in the development of psychiatric disorders later in life. The present study was designed to investigate the prenatal features of KP metabolism in vivo, with special focus on KYNA. To this end, pregnant CD-1 mice were treated systemically with kynurenine (100 mg/kg), KYNA (10 mg/kg), or saline on embryonic day 18. As expected, administration of either kynurenine or KYNA increased KYNA levels in the maternal plasma and placenta. Maternal kynurenine treatment also raised kynurenine levels in the fetal plasma and brain, demonstrating the ability of this pivotal KP metabolite to cross the placenta and increase the levels of both KYNA and 3-HK in the fetal brain. In contrast, maternal administration of KYNA caused only a small, nonsignificant elevation in KYNA levels in fetal plasma and brain. Complementary experiments using an ex vivo placental perfusion procedure confirmed the significant transplacental transfer of kynurenine and demonstrated that only a very small fraction of maternal kynurenine is converted to KYNA in the placenta and released into the fetal compartment under physiological conditions. Jointly, these results help to clarify the contributions of the maternal circulation and the placenta to fetal KYNA in the late prenatal period.
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Affiliation(s)
- Nick Goeden
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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48
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Brown AG, Tulina NM, Barila GO, Hester MS, Elovitz MA. Exposure to intrauterine inflammation alters metabolomic profiles in the amniotic fluid, fetal and neonatal brain in the mouse. PLoS One 2017; 12:e0186656. [PMID: 29049352 PMCID: PMC5648237 DOI: 10.1371/journal.pone.0186656] [Citation(s) in RCA: 28] [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: 07/24/2017] [Accepted: 10/04/2017] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Exposure to prenatal inflammation is associated with diverse adverse neurobehavioral outcomes in exposed offspring. The mechanism by which inflammation negatively impacts the developing brain is poorly understood. Metabolomic profiling provides an opportunity to identify specific metabolites, and novel pathways, which may reveal mechanisms by which exposure to intrauterine inflammation promotes fetal and neonatal brain injury. Therefore, we investigated whether exposure to intrauterine inflammation altered the metabolome of the amniotic fluid, fetal and neonatal brain. Additionally, we explored whether changes in the metabolomic profile from exposure to prenatal inflammation occurs in a sex-specific manner in the neonatal brain. METHODS CD-1, timed pregnant mice received an intrauterine injection of lipopolysaccharide (50 μg/dam) or saline on embryonic day 15. Six and 48 hours later mice were sacrificed and amniotic fluid, and fetal brains were collected (n = 8/group). Postnatal brains were collected on day of life 1 (n = 6/group/sex). Global biochemical profiles were determined using ultra performance liquid chromatography/tandem mass spectrometry (Metabolon Inc.). Statistical analyses were performed by comparing samples from lipopolysaccharide and saline treated animals at each time point. For the P1 brains, analyses were stratified by sex. RESULTS/CONCLUSIONS Exposure to intrauterine inflammation induced unique, temporally regulated changes in the metabolic profiles of amniotic fluid, fetal brain and postnatal brain. Six hours after exposure to intrauterine inflammation, the amniotic fluid and the fetal brain metabolomes were dramatically altered with significant enhancements of amino acid and purine metabolites. The amniotic fluid had enhanced levels of several members of the (hypo) xanthine pathway and this compound was validated as a potential biomarker. By 48 hours, the number of altered biochemicals in both the fetal brain and the amniotic fluid had declined, yet unique profiles existed. Neonatal pups exposed to intrauterine inflammation have significant alterations in their lipid metabolites, in particular, fatty acids. These sex-specific metabolic changes within the newborn brain offer an explanation regarding the sexual dimorphism of certain psychiatric and neurobehavioral disorders associated with exposure to prenatal inflammation.
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Affiliation(s)
- Amy G. Brown
- Maternal Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Natalia M. Tulina
- Maternal Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Guillermo O. Barila
- Maternal Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael S. Hester
- Maternal Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michal A. Elovitz
- Maternal Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Kelly JR, Minuto C, Cryan JF, Clarke G, Dinan TG. Cross Talk: The Microbiota and Neurodevelopmental Disorders. Front Neurosci 2017; 11:490. [PMID: 28966571 PMCID: PMC5605633 DOI: 10.3389/fnins.2017.00490] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/17/2017] [Indexed: 12/11/2022] Open
Abstract
Humans evolved within a microbial ecosystem resulting in an interlinked physiology. The gut microbiota can signal to the brain via the immune system, the vagus nerve or other host-microbe interactions facilitated by gut hormones, regulation of tryptophan metabolism and microbial metabolites such as short chain fatty acids (SCFA), to influence brain development, function and behavior. Emerging evidence suggests that the gut microbiota may play a role in shaping cognitive networks encompassing emotional and social domains in neurodevelopmental disorders. Drawing upon pre-clinical and clinical evidence, we review the potential role of the gut microbiota in the origins and development of social and emotional domains related to Autism spectrum disorders (ASD) and schizophrenia. Small preliminary clinical studies have demonstrated gut microbiota alterations in both ASD and schizophrenia compared to healthy controls. However, we await the further development of mechanistic insights, together with large scale longitudinal clinical trials, that encompass a systems level dimensional approach, to investigate whether promising pre-clinical and initial clinical findings lead to clinical relevance.
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Affiliation(s)
- John R Kelly
- Department of Psychiatry and Neurobehavioural Science, University College CorkCork, Ireland.,APC Microbiome Institute, University College CorkCork, Ireland
| | - Chiara Minuto
- Department of Psychiatry and Neurobehavioural Science, University College CorkCork, Ireland.,APC Microbiome Institute, University College CorkCork, Ireland
| | - John F Cryan
- APC Microbiome Institute, University College CorkCork, Ireland.,Department of Anatomy and Neuroscience, University College CorkCork, Ireland
| | - Gerard Clarke
- Department of Psychiatry and Neurobehavioural Science, University College CorkCork, Ireland.,APC Microbiome Institute, University College CorkCork, Ireland
| | - Timothy G Dinan
- Department of Psychiatry and Neurobehavioural Science, University College CorkCork, Ireland.,APC Microbiome Institute, University College CorkCork, Ireland
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Preferential Disruption of Prefrontal GABAergic Function by Nanomolar Concentrations of the α7nACh Negative Modulator Kynurenic Acid. J Neurosci 2017; 37:7921-7929. [PMID: 28729445 DOI: 10.1523/jneurosci.0932-17.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/20/2017] [Accepted: 07/11/2017] [Indexed: 12/27/2022] Open
Abstract
Increased concentrations of kynurenic acid (KYNA) in the prefrontal cortex (PFC) are thought to contribute to the development of cognitive deficits observed in schizophrenia. Although this view is consistent with preclinical studies showing a negative impact of prefrontal KYNA elevation on executive function, the mechanism underlying such a disruption remains unclear. Here, we measured changes in local field potential (LFP) responses to ventral hippocampal stimulation in vivo and conducted whole-cell patch-clamp recordings in brain slices to reveal how nanomolar concentrations of KYNA alter synaptic transmission in the PFC of male adult rats. Our data show that prefrontal infusions of KYNA attenuated the inhibitory component of PFC LFP responses, a disruption that resulted from local blockade of α7-nicotinic acetylcholine receptors (α7nAChR). At the cellular level, we found that the inhibitory action exerted by KYNA in the PFC occurred primarily at local GABAergic synapses through an α7nAChR-dependent presynaptic mechanism. As a result, the excitatory-inhibitory ratio of synaptic transmission becomes imbalanced in a manner that correlates highly with the level of GABAergic suppression by KYNA. Finally, prefrontal infusion of a GABAAR positive allosteric modulator was sufficient to overcome the disrupting effect of KYNA and normalized the pattern of LFP inhibition in the PFC. Thus, the preferential inhibitory effect of KYNA on prefrontal GABAergic transmission could contribute to the onset of cognitive deficits observed in schizophrenia because proper GABAergic control of PFC output is one key mechanism for supporting such cortical functions.SIGNIFICANCE STATEMENT Brain kynurenic acid (KYNA) is an astrocyte-derived metabolite and its abnormal elevation in the prefrontal cortex (PFC) is thought to impair cognitive functions in individuals with schizophrenia. However, the mechanism underlying the disrupting effect of KYNA remains unclear. Here we found that KYNA biases the excitatory-inhibitory balance of prefrontal synaptic activity toward a state of disinhibition. Such disruption emerges as a result of a preferential suppression of local GABAergic transmission by KYNA via presynaptic inhibition of α7-nicotinic acetylcholine receptor signaling. Therefore, the degree of GABAergic dysregulation in the PFC could be a clinically relevant contributing factor for the onset of cognitive deficits resulting from abnormal increases of cortical KYNA.
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