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Shen H, Xu X, Bai Y, Wang X, Wu Y, Zhong J, Wu Q, Luo Y, Shang T, Shen R, Xi M, Sun H. Therapeutic potential of targeting kynurenine pathway in neurodegenerative diseases. Eur J Med Chem 2023; 251:115258. [PMID: 36917881 DOI: 10.1016/j.ejmech.2023.115258] [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: 01/25/2023] [Revised: 02/17/2023] [Accepted: 03/07/2023] [Indexed: 03/11/2023]
Abstract
Kynurenine pathway (KP), the primary pathway of L-tryptophan (Trp) metabolism in mammals, contains several neuroactive metabolites such as kynurenic acid (KA) and quinolinic acid (QA). Its imbalance involved in aging and neurodegenerative diseases (NDs) has attracted much interest in therapeutically targeting KP enzymes and KP metabolite-associated receptors, especially kynurenine monooxygenase (KMO). Currently, many agents have been discovered with significant improvement in animal models but only one aryl hydrocarbon receptor (AHR) agonist 30 (laquinimod) has entered clinical trials for treating Huntington's disease (HD). In this review, we describe neuroactive KP metabolites, discuss the dysregulation of KP in aging and NDs and summarize the development of KP regulators in preclinical and clinical studies, offering an outlook of targeting KP for NDs treatment in future.
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Affiliation(s)
- Hualiang Shen
- Zhejiang Engineering Research Center of Fat-soluble Vitamin, Shaoxing University, Shaoxing, 312000, China; College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Xinde Xu
- Zhejiang Medicine Co. Ltd., Shaoxing, 312500, China
| | - Yalong Bai
- Zhejiang Medicine Co. Ltd., Shaoxing, 312500, China
| | | | - Yibin Wu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Jia Zhong
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Qiyi Wu
- College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Yanjuan Luo
- Zhejiang Engineering Research Center of Fat-soluble Vitamin, Shaoxing University, Shaoxing, 312000, China; College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Tianbo Shang
- Zhejiang Engineering Research Center of Fat-soluble Vitamin, Shaoxing University, Shaoxing, 312000, China; College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Runpu Shen
- Zhejiang Engineering Research Center of Fat-soluble Vitamin, Shaoxing University, Shaoxing, 312000, China; College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Meiyang Xi
- Zhejiang Engineering Research Center of Fat-soluble Vitamin, Shaoxing University, Shaoxing, 312000, China; College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China.
| | - Haopeng Sun
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, 210009, China.
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2
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Chowdhury R. Eosin-Y/Cu(OAc) 2-catalyzed aerobic oxidative coupling reactions of glycine esters in the dark. Org Biomol Chem 2022; 20:5387-5392. [PMID: 35748811 DOI: 10.1039/d2ob00678b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Catalytic aerobic oxidative coupling reactions of glycine esters with β-keto acids, indoles, naphthols, and pyrrole have been realized at ambient temperature via the manipulation of the ground state reactivity of eosin-Y in the presence of Cu(OAc)2 in the dark. This method delivers structurally diverse unnatural amino acid derivatives under mild reaction conditions. UV-vis absorption spectroscopy, cyclic voltammetry, X-ray photoelectron spectroscopy, high-resolution mass spectrometry, and control experiments were performed to formulate a plausible mechanistic pathway. The step economy, broad substrate scope, use of air as a green oxidant, and operationally simple set-up make this protocol highly appealing for both academic and industrial applications.
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Affiliation(s)
- Raghunath Chowdhury
- Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India. .,Homi Bhabha National Institute, Anushaktingar, Mumbai-94, India
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3
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Sathyasaikumar KV, Pérez de la Cruz V, Pineda B, Vázquez Cervantes GI, Ramírez Ortega D, Donley DW, Severson PL, West BL, Giorgini F, Fox JH, Schwarcz R. Cellular Localization of Kynurenine 3-Monooxygenase in the Brain: Challenging the Dogma. Antioxidants (Basel) 2022; 11:antiox11020315. [PMID: 35204197 PMCID: PMC8868204 DOI: 10.3390/antiox11020315] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 02/07/2023] Open
Abstract
Kynurenine 3-monooxygenase (KMO), a key player in the kynurenine pathway (KP) of tryptophan degradation, regulates the synthesis of the neuroactive metabolites 3-hydroxykynurenine (3-HK) and kynurenic acid (KYNA). KMO activity has been implicated in several major brain diseases including Huntington’s disease (HD) and schizophrenia. In the brain, KMO is widely believed to be predominantly localized in microglial cells, but verification in vivo has not been provided so far. Here, we examined KP metabolism in the brain after depleting microglial cells pharmacologically with the colony stimulating factor 1 receptor inhibitor PLX5622. Young adult mice were fed PLX5622 for 21 days and were euthanized either on the next day or after receiving normal chow for an additional 21 days. Expression of microglial marker genes was dramatically reduced on day 22 but had fully recovered by day 43. In both groups, PLX5622 treatment failed to affect Kmo expression, KMO activity or tissue levels of 3-HK and KYNA in the brain. In a parallel experiment, PLX5622 treatment also did not reduce KMO activity, 3-HK and KYNA in the brain of R6/2 mice (a model of HD with activated microglia). Finally, using freshly isolated mouse cells ex vivo, we found KMO only in microglia and neurons but not in astrocytes. Taken together, these data unexpectedly revealed that neurons contain a large proportion of functional KMO in the adult mouse brain under both physiological and pathological conditions.
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Affiliation(s)
- Korrapati V. Sathyasaikumar
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA;
| | - Verónica Pérez de la Cruz
- Neurobiochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (V.P.d.l.C.); (G.I.V.C.); (D.R.O.)
| | - Benjamín Pineda
- Neuroimmunology Department, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico;
| | - Gustavo Ignacio Vázquez Cervantes
- Neurobiochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (V.P.d.l.C.); (G.I.V.C.); (D.R.O.)
| | - Daniela Ramírez Ortega
- Neurobiochemistry and Behavior Laboratory, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, Mexico City 14269, Mexico; (V.P.d.l.C.); (G.I.V.C.); (D.R.O.)
| | - David W. Donley
- Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82071, USA; (D.W.D.); (J.H.F.)
| | - Paul L. Severson
- Plexxikon Inc., South San Francisco, CA 94080, USA; (P.L.S.); (B.L.W.)
| | - Brian L. West
- Plexxikon Inc., South San Francisco, CA 94080, USA; (P.L.S.); (B.L.W.)
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7JA, UK;
| | - Jonathan H. Fox
- Department of Veterinary Sciences, University of Wyoming, Laramie, WY 82071, USA; (D.W.D.); (J.H.F.)
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA;
- Correspondence: ; Tel.: +1-410-402-7635
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The Kynurenine Pathway and Kynurenine 3-Monooxygenase Inhibitors. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27010273. [PMID: 35011505 PMCID: PMC8747024 DOI: 10.3390/molecules27010273] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 12/20/2022]
Abstract
Under normal physiological conditions, the kynurenine pathway (KP) plays a critical role in generating cellular energy and catabolizing tryptophan. Under inflammatory conditions, however, there is an upregulation of the KP enzymes, particularly kynurenine 3-monooxygenase (KMO). KMO has garnered much attention due to its production of toxic metabolites that have been implicated in many diseases and disorders. With many of these illnesses having an inadequate or modest treatment, there exists a need to develop KMO inhibitors that reduce the production of these toxic metabolites. Though prior efforts to find an appropriate KMO inhibitor were unpromising, the development of a KMO crystal structure has provided the opportunity for a rational structure-based design in the development of inhibitors. Therefore, the purpose of this review is to describe the kynurenine pathway, the kynurenine 3-monooxygenase enzyme, and KMO inhibitors and their potential candidacy for clinical use.
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Curry A, White D, Cen Y. Small Molecule Regulators Targeting NAD + Biosynthetic Enzymes. Curr Med Chem 2022; 29:1718-1738. [PMID: 34060996 PMCID: PMC8630097 DOI: 10.2174/0929867328666210531144629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 01/03/2023]
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a key player in many metabolic pathways as an activated carrier of electrons. In addition to being the cofactor for redox reactions, NAD+ also serves as the substrate for various enzymatic transformations such as adenylation and ADP-ribosylation. Maintaining cellular NAD+ homeostasis has been suggested as an effective anti-aging strategy. Given the importance of NAD+ in regulating a broad spectrum of cellular events, small molecules targeting NAD+ metabolism have been pursued as therapeutic interventions for the treatment of mitochondrial disorders and agerelated diseases. In this article, small molecule regulators of NAD+ biosynthetic enzymes will be reviewed. The focus will be given to the discovery and development of these molecules, the mechanism of action as well as their therapeutic potentials.
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Affiliation(s)
- Alyson Curry
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Dawanna White
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Yana Cen
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA;,Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA 23219, USA,Address correspondence to this author at the Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA; Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA 23219, USA; Tel: 804-828-7405;
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Ostapiuk A, Urbanska EM. Kynurenic acid in neurodegenerative disorders-unique neuroprotection or double-edged sword? CNS Neurosci Ther 2022; 28:19-35. [PMID: 34862742 PMCID: PMC8673711 DOI: 10.1111/cns.13768] [Citation(s) in RCA: 31] [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: 08/05/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 12/24/2022] Open
Abstract
AIMS The family of kynurenine pathway (KP) metabolites includes compounds produced along two arms of the path and acting in clearly opposite ways. The equilibrium between neurotoxic kynurenines, such as 3-hydroxykynurenine (3-HK) or quinolinic acid (QUIN), and neuroprotective kynurenic acid (KYNA) profoundly impacts the function and survival of neurons. This comprehensive review summarizes accumulated evidence on the role of KYNA in Alzheimer's, Parkinson's and Huntington's diseases, and discusses future directions of potential pharmacological manipulations aimed to modulate brain KYNA. DISCUSSION The synthesis of specific KP metabolites is tightly regulated and may considerably vary under physiological and pathological conditions. Experimental data consistently imply that shift of the KP to neurotoxic branch producing 3-HK and QUIN formation, with a relative or absolute deficiency of KYNA, is an important factor contributing to neurodegeneration. Targeting specific brain regions to maintain adequate KYNA levels seems vital; however, it requires the development of precise pharmacological tools, allowing to avoid the potential cognitive adverse effects. CONCLUSIONS Boosting KYNA levels, through interference with the KP enzymes or through application of prodrugs/analogs with high bioavailability and potency, is a promising clinical approach. The use of KYNA, alone or in combination with other compounds precisely influencing specific populations of neurons, is awaiting to become a significant therapy for neurodegenerative disorders.
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Affiliation(s)
- Aleksandra Ostapiuk
- Laboratory of Cellular and Molecular PharmacologyDepartment of Experimental and Clinical PharmacologyMedical University of LublinLublinPoland
- Present address:
Department of Clinical Digestive OncologyKU LeuvenLeuvenBelgium
| | - Ewa M. Urbanska
- Laboratory of Cellular and Molecular PharmacologyDepartment of Experimental and Clinical PharmacologyMedical University of LublinLublinPoland
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Serum kynurenine metabolites might not be associated with risk factors of treatment-resistant schizophrenia. J Psychiatr Res 2022; 145:339-346. [PMID: 34776248 DOI: 10.1016/j.jpsychires.2021.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 10/11/2021] [Accepted: 11/02/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND About a third of patients with schizophrenia do not respond adequately to currently available antipsychotics and thus experiences symptoms of greater severity, known as treatment-resistant schizophrenia (TRS). Some evidence suggests that the tryptophan (TRP) pathway (comprising 5-HT and kynurenine sub-pathways) has an important influence on response to antipsychotics. We therefore hypothesized that TRS is linked to metabolites of TRP pathway. METHODS We measured TRP metabolites in 54 patients with TRS and compared them to 49 age- and sex-matched patients who responded to antipsychotics (NTRS), and 62 healthy controls using liquid chromatography-tandem mass spectrometry. Psychopathology and clinical symptoms were assessed by means of schizophrenia positive and negative scales. Working memory abilities, cortical thickness and white matter diffusion tensor imaging fractional anisotropy were appraised in enrolled subjects by neurophysiological tests, as spatial span and digital sequencing tests, and 3T magnetic resonance imaging. RESULTS Patients with TRS had a significantly higher 5-HT/TRP ratio (p = 0.009) than patients with NTRS. However, the two groups did not differ in kynurenine-pathway metabolites or ratios. Additionally, 5-HT/TRP was positively correlated with disorganized symptoms in TRS (r = 0.59, p < 0.001), and negatively correlated with digit-sequencing test scores (r = -0.34, p = 0.02). These correlations were insignificant among patients with NTRS and healthy controls. In patients with TRS, 5-HT/TRP was strongly linked to the right supramarginal cortex (t = -3.2, p = 0.003), and in healthy controls, to the right transverse temporal (t = 3.40, p = 0.001), but significance disappeared after FDR correction. CONCLUSIONS Present results indicate that an upregulated 5-HT biosynthetic pathway can be associated to TRS, suggesting that targeting mechanisms of 5-HT conversion from tryptophan could shed light on the development of new pharmacological approaches of TRS.
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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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Collier ME, Zhang S, Scrutton NS, Giorgini F. Inflammation control and improvement of cognitive function in COVID-19 infections: is there a role for kynurenine 3-monooxygenase inhibition? Drug Discov Today 2021; 26:1473-1481. [PMID: 33609782 PMCID: PMC7889466 DOI: 10.1016/j.drudis.2021.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/26/2021] [Accepted: 02/10/2021] [Indexed: 02/07/2023]
Abstract
The novel respiratory virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), emerged during late 2019 and spread rapidly across the world. It is now recognised that the nervous system can be affected in COVID-19, with several studies reporting long-term cognitive problems in patients. The metabolic pathway of tryptophan degradation, known as the kynurenine pathway (KP), is significantly activated in patients with COVID-19. KP metabolites have roles in regulating both inflammatory/immune responses and neurological functions. In this review, we speculate on the effects of KP activation in patients with COVID-19, and how modulation of this pathway might impact inflammation and reduce neurological symptoms.
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Affiliation(s)
- Mary Ew Collier
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK.
| | - Shaowei Zhang
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
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10
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Huang J, Tong J, Zhang P, Zhou Y, Cui Y, Tan S, Wang Z, Yang F, Kochunov P, Chiappelli J, Tian B, Tian L, Tan Y, Hong LE. Effects of neuroactive metabolites of the tryptophan pathway on working memory and cortical thickness in schizophrenia. Transl Psychiatry 2021; 11:198. [PMID: 33795641 PMCID: PMC8016899 DOI: 10.1038/s41398-021-01311-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/19/2021] [Accepted: 03/11/2021] [Indexed: 01/10/2023] Open
Abstract
A number of tryptophan metabolites known to be neuroactive have been examined for their potential associations with cognitive deficits in schizophrenia. Among these metabolites, kynurenic acid (KYNA), 5-hydroxyindole (5-HI), and quinolinic acid (QUIN) are documented in their diverse effects on α-7 nicotinic acetylcholine receptor (α7nAChR) and/or N-methyl-D-aspartate receptor (NMDAR), two of the receptor types thought to contribute to cognitive impairment in schizophrenia. In this study, serum levels of KYNA, 5-HI, and QUIN were measured in 195 patients with schizophrenia and in 70 healthy controls using liquid chromatography-tandem mass spectrometry; cognitive performance in MATRICS Consensus Cognitive Battery and cortical thickness measured by magnetic resonance imaging were obtained. Patients with schizophrenia had significantly lower serum KYNA (p < 0.001) and QUIN (p = 0.02) levels, and increased 5-HI/KYNA (p < 0.001) and QUIN/KYNA ratios (p < 0.001) compared with healthy controls. Multiple linear regression showed that working memory was positively correlated with serum 5-HI levels (t = 2.10, p = 0.04), but inversely correlated with KYNA concentrations (t = -2.01, p = 0.05) in patients. Patients with high 5-HI and low KYNA had better working memory than other subgroups (p = 0.01). Higher 5-HI levels were associated with thicker left lateral orbitofrontal cortex (t = 3.71, p = 2.94 × 10-4) in patients. The different effects of 5-HI and KYNA on working memory may appear consistent with their opposite receptor level mechanisms. Our findings appear to provide a new insight into the dynamic roles of tryptophan pathway metabolites on cognition, which may benefit novel therapeutic development that targets cognitive impairment in schizophrenia.
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Affiliation(s)
- Junchao Huang
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Jinghui Tong
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Ping Zhang
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Yanfang Zhou
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Yimin Cui
- grid.411472.50000 0004 1764 1621Department of Pharmacy, Peking University First Hospital, Beijing, China
| | - Shuping Tan
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Zhiren Wang
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Fude Yang
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Peter Kochunov
- grid.411024.20000 0001 2175 4264Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD USA
| | - Joshua Chiappelli
- grid.411024.20000 0001 2175 4264Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD USA
| | - Baopeng Tian
- grid.414351.60000 0004 0530 7044Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China
| | - Li Tian
- grid.10939.320000 0001 0943 7661Faculty of Medicine, Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Yunlong Tan
- Peking University HuiLongGuan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, China.
| | - L. Elliot Hong
- grid.411024.20000 0001 2175 4264Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD USA
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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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Zhang S, Collier MEW, Heyes DJ, Giorgini F, Scrutton NS. Advantages of brain penetrating inhibitors of kynurenine-3-monooxygenase for treatment of neurodegenerative diseases. Arch Biochem Biophys 2020; 697:108702. [PMID: 33275878 DOI: 10.1016/j.abb.2020.108702] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/18/2020] [Accepted: 11/24/2020] [Indexed: 01/16/2023]
Abstract
Kynurenine-3-monooxygenase (KMO) is an important therapeutic target for several brain disorders that has been extensively studied in recent years. Potent inhibitors towards KMO have been developed and tested within different disease models, showing great therapeutic potential, especially in models of neurodegenerative disease. The inhibition of KMO reduces the production of downstream toxic kynurenine pathway metabolites and shifts the flux to the formation of the neuroprotectant kynurenic acid. However, the efficacy of KMO inhibitors in neurodegenerative disease has been limited by their poor brain permeability. Combined with virtual screening and prodrug strategies, a novel brain penetrating KMO inhibitor has been developed which dramatically decreases neurotoxic metabolites. This review highlights the importance of KMO as a drug target in neurological disease and the benefits of brain permeable inhibitors in modulating kynurenine pathway metabolites in the central nervous system.
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Affiliation(s)
- Shaowei Zhang
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Mary E W Collier
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Derren J Heyes
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
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13
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Beaupre BA, Reabe KR, Roman JV, Moran GR. Hydrogen movements in the oxidative half-reaction of kynurenine 3-monooxygenase from Pseudomonas fluorescens reveal the mechanism of hydroxylation. Arch Biochem Biophys 2020; 690:108474. [PMID: 32687799 DOI: 10.1016/j.abb.2020.108474] [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: 05/01/2020] [Revised: 06/08/2020] [Accepted: 06/17/2020] [Indexed: 11/30/2022]
Abstract
Kynurenine 3-monoxygenase (KMO) catalyzes the conversion of l-kynurenine (L-Kyn) to 3-hydroxykynurenine (3-OHKyn) in the pathway for tryptophan catabolism. We have investigated the effects of pH and deuterium substitution on the oxidative half-reaction of KMO from P. fluorescens (PfKMO). The three phases observed during the oxidative half reaction are formation of the hydroperoxyflavin, hydroxylation and product release. The measured rate constants for these phases proved largely unchanging with pH, suggesting that the KMO active site is insulated from exchange with solvent during catalysis. A solvent inventory study indicated that a solvent isotope effect of 2-3 is observed for the hydroxylation phase and that two or more protons are in flight during this step. An inverse isotope effect of 0.84 ± 0.01 on the rate constant for the hydroxylation step with ring perdeutero-L-Kyn as a substrate indicates a shift from sp2 to sp3 hybridization in the transition state leading to the formation of a non-aromatic intermediate. The pH dependence of transient state data collected for the substrate analog meta-nitrobenzoylalanine indicate that groups proximal to the hydroperoxyflavin are titrated in the range pH 5-8.5 and can be described by a pKa of 8.8. That higher pH values do not slow the rate of hydroxylation precludes that the pKa measured pertains to the proton of the hydroperoxflavin. Together, these observations indicate that the C4a-hydroperoxyflavin has a pKa ≫ 8.5, that a non-aromatic species is the immediate product of hydroxylation and that at least two solvent derived protons are in-flight during oxygen insertion to the substrate aromatic ring. A unifying mechanistic proposal for these observations is proposed.
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Affiliation(s)
- Brett A Beaupre
- Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Loyola University Chicago, Chicago, IL, 60660, USA
| | - Karen R Reabe
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 N. Cramer Street, Milwaukee, WI, 53211-3029, USA
| | - Joseph V Roman
- Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Loyola University Chicago, Chicago, IL, 60660, USA
| | - Graham R Moran
- Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Loyola University Chicago, Chicago, IL, 60660, USA.
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14
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Jagatheesan R, Ramesh P, Sambathkumar S. Selective α-bromination of aryl carbonyl compounds: prospects and challenges. SYNTHETIC COMMUN 2019. [DOI: 10.1080/00397911.2019.1668415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Rathinavel Jagatheesan
- Department of Chemistry, Vivekanandha College of Arts and Sciences for Women (Autonomous), Tiruchengode, Namakkal, Tamil Nadu, India
| | - Pugalenthi Ramesh
- Department of Chemistry, Vivekanandha College of Arts and Sciences for Women (Autonomous), Tiruchengode, Namakkal, Tamil Nadu, India
| | - Subramaniyan Sambathkumar
- Department of Chemistry, Vivekanandha College of Arts and Sciences for Women (Autonomous), Tiruchengode, Namakkal, Tamil Nadu, India
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15
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Zhang S, Sakuma M, Deora GS, Levy CW, Klausing A, Breda C, Read KD, Edlin CD, Ross BP, Wright Muelas M, Day PJ, O’Hagan S, Kell DB, Schwarcz R, Leys D, Heyes DJ, Giorgini F, Scrutton NS. A brain-permeable inhibitor of the neurodegenerative disease target kynurenine 3-monooxygenase prevents accumulation of neurotoxic metabolites. Commun Biol 2019; 2:271. [PMID: 31372510 PMCID: PMC6656724 DOI: 10.1038/s42003-019-0520-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 06/28/2019] [Indexed: 12/16/2022] Open
Abstract
Dysregulation of the kynurenine pathway (KP) leads to imbalances in neuroactive metabolites associated with the pathogenesis of several neurodegenerative disorders, including Huntington's disease (HD). Inhibition of the enzyme kynurenine 3-monooxygenase (KMO) in the KP normalises these metabolic imbalances and ameliorates neurodegeneration and related phenotypes in several neurodegenerative disease models. KMO is thus a promising candidate drug target for these disorders, but known inhibitors are not brain permeable. Here, 19 new KMO inhibitors have been identified. One of these (1) is neuroprotective in a Drosophila HD model but is minimally brain penetrant in mice. The prodrug variant (1b) crosses the blood-brain barrier, releases 1 in the brain, thereby lowering levels of 3-hydroxykynurenine, a toxic KP metabolite linked to neurodegeneration. Prodrug 1b will advance development of targeted therapies against multiple neurodegenerative and neuroinflammatory diseases in which KP likely plays a role, including HD, Alzheimer's disease, and Parkinson's disease.
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Affiliation(s)
- Shaowei Zhang
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Michiyo Sakuma
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Girdhar S. Deora
- School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 Australia
| | - Colin W. Levy
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Alex Klausing
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228 USA
| | - Carlo Breda
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH UK
| | - Kevin D. Read
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee, Scotland DD1 5EH UK
| | | | - Benjamin P. Ross
- School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 Australia
| | - Marina Wright Muelas
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Philip J. Day
- Manchester Institute of Biotechnology and Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PL UK
| | - Stephen O’Hagan
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Douglas B. Kell
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228 USA
| | - David Leys
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Derren J. Heyes
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH UK
| | - Nigel S. Scrutton
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN UK
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16
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de Oliveira FR, Fantucci MZ, Adriano L, Valim V, Cunha TM, Louzada-Junior P, Rocha EM. Neurological and Inflammatory Manifestations in Sjögren's Syndrome: The Role of the Kynurenine Metabolic Pathway. Int J Mol Sci 2018; 19:ijms19123953. [PMID: 30544839 PMCID: PMC6321004 DOI: 10.3390/ijms19123953] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/04/2018] [Accepted: 12/06/2018] [Indexed: 12/16/2022] Open
Abstract
For decades, neurological, psychological, and cognitive alterations, as well as other glandular manifestations (EGM), have been described and are being considered to be part of Sjögren's syndrome (SS). Dry eye and dry mouth are major findings in SS. The lacrimal glands (LG), ocular surface (OS), and salivary glands (SG) are linked to the central nervous system (CNS) at the brainstem and hippocampus. Once compromised, these CNS sites may be responsible for autonomic and functional disturbances that are related to major and EGM in SS. Recent studies have confirmed that the kynurenine metabolic pathway (KP) can be stimulated by interferon-γ (IFN-γ) and other cytokines, activating indoleamine 2,3-dioxygenase (IDO) in SS. This pathway interferes with serotonergic and glutamatergic neurotransmission, mostly in the hippocampus and other structures of the CNS. Therefore, it is plausible that KP induces neurological manifestations and contributes to the discrepancy between symptoms and signs, including manifestations of hyperalgesia and depression in SS patients with weaker signs of sicca, for example. Observations from clinical studies in acquired immune deficiency syndrome (AIDS), graft-versus-host disease, and lupus, as well as from experimental studies, support this hypothesis. However, the obtained results for SS are controversial, as discussed in this study. Therapeutic strategies have been reexamined and new options designed and tested to regulate the KP. In the future, the confirmation and application of this concept may help to elucidate the mosaic of SS manifestations.
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Affiliation(s)
- Fabíola Reis de Oliveira
- Ribeirao Preto Medical School, Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14049-900 Brazil.
| | - Marina Zilio Fantucci
- Ribeirao Preto Medical School, Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14049-900 Brazil.
| | - Leidiane Adriano
- Ribeirao Preto Medical School, Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14049-900 Brazil.
| | - Valéria Valim
- Espírito Santo Federal University, Vitoria, ES 29075-910, Brazil.
| | - Thiago Mattar Cunha
- Ribeirao Preto Medical School, Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14049-900 Brazil.
| | - Paulo Louzada-Junior
- Ribeirao Preto Medical School, Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14049-900 Brazil.
| | - Eduardo Melani Rocha
- Ribeirao Preto Medical School, Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14049-900 Brazil.
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17
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Sharma R, Razdan K, Bansal Y, Kuhad A. Rollercoaster ride of kynurenines: steering the wheel towards neuroprotection in Alzheimer's disease. Expert Opin Ther Targets 2018; 22:849-867. [PMID: 30223691 DOI: 10.1080/14728222.2018.1524877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Alzheimer's disease (AD) is associated with cerebral cognitive deficits exhibiting two cardinal hallmarks: accruement of extracellular amyloid plaques and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein. The currently accessible therapeutic armamentarium merely provides symptomatic relief. Therefore, the cry for prospective neuroprotective strategies seems to be the need of the hour. Areas covered: This review comprehensively establishes correlation between kynurenine pathway (KP) metabolites and AD with major emphasis on its two functionally contrasting neuroactive metabolites i.e. kynurenic acid (KYNA) and quinolinic acid (QUIN) and enlists various clinical studies which hold a potential for future therapeutics in AD. Also, major hypotheses of AD and mechanisms underlying them have been scrutinized with the aim to brush up the readers with basic pathology of AD. Expert opinion: KP is unique in itself as it holds two completely different domains i.e. neurotoxic QUIN and neuroprotective KYNA and disrupted equilibrium between the two has a hand in neurodegeneration. KYNA has long been demonstrated to be neuroprotective but lately being disparaged for cognitive side effects. But we blaze a trail by amalgamating the pharmacological mechanistic studies of KYNA in kinship with α7nAChRs, NMDARs and GABA which lends aid in favour of KA.
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Affiliation(s)
- Radhika Sharma
- a Pharmacology Research Laboratory , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
| | - Karan Razdan
- b Pharmaceutics division , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
| | - Yashika Bansal
- a Pharmacology Research Laboratory , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
| | - Anurag Kuhad
- a Pharmacology Research Laboratory , University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study, Panjab University , Chandigarh , India
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18
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Pellicciari R, Liscio P, Giacchè N, De Franco F, Carotti A, Robertson J, Cialabrini L, Katsyuba E, Raffaelli N, Auwerx J. α-Amino-β-carboxymuconate-ε-semialdehyde Decarboxylase (ACMSD) Inhibitors as Novel Modulators of De Novo Nicotinamide Adenine Dinucleotide (NAD +) Biosynthesis. J Med Chem 2018; 61:745-759. [PMID: 29345930 DOI: 10.1021/acs.jmedchem.7b01254] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
NAD+ has a central function in linking cellular metabolism to major cell-signaling and gene-regulation pathways. Defects in NAD+ homeostasis underpin a wide range of diseases, including cancer, metabolic disorders, and aging. Although the beneficial effects of boosting NAD+ on mitochondrial fitness, metabolism, and lifespan are well established, to date, no therapeutic enhancers of de novo NAD+ biosynthesis have been reported. Herein we report the discovery of 3-[[[5-cyano-1,6-dihydro-6-oxo-4-(2-thienyl)-2-pyrimidinyl]thio]methyl]phenylacetic acid (TES-1025, 22), the first potent and selective inhibitor of human ACMSD (IC50 = 0.013 μM) that increases NAD+ levels in cellular systems. The results of physicochemical-property, ADME, and safety profiling, coupled with in vivo target-engagement studies, support the hypothesis that ACMSD inhibition increases de novo NAD+ biosynthesis and position 22 as a first-class molecule for the evaluation of the therapeutic potential of ACMSD inhibition in treating disorders with perturbed NAD+ supply or homeostasis.
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Affiliation(s)
| | - Paride Liscio
- TES Pharma S.r.l. , IT-06073 Corciano, Perugia, Italy
| | | | | | - Andrea Carotti
- Department of Pharmaceutical Sciences, University of Perugia , IT-06123 Perugia, Italy
| | | | - Lucia Cialabrini
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche , IT-60131 Ancona, Italy
| | - Elena Katsyuba
- Laboratory of Integrative and Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne CH-1015 Lausanne, Switzerland
| | - Nadia Raffaelli
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche , IT-60131 Ancona, Italy
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne CH-1015 Lausanne, Switzerland
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19
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Sathyasaikumar KV, Breda C, Schwarcz R, Giorgini F. Assessing and Modulating Kynurenine Pathway Dynamics in Huntington's Disease: Focus on Kynurenine 3-Monooxygenase. Methods Mol Biol 2018; 1780:397-413. [PMID: 29856028 DOI: 10.1007/978-1-4939-7825-0_18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The link between disturbances in kynurenine pathway (KP) metabolism and Huntington's disease (HD) pathogenesis has been explored for a number of years. Several novel genetic and pharmacological tools have recently been developed to modulate key regulatory steps in the KP such as the reaction catalyzed by the enzyme kynurenine 3-monooxygenase (KMO). This insight has offered new options for exploring the mechanistic link between this metabolic pathway and HD, and provided novel opportunities for the development of candidate drug-like compounds. Here, we present an overview of the field, focusing on some novel approaches for interrogating the pathway experimentally.
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Affiliation(s)
- Korrapati V Sathyasaikumar
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Carlo Breda
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK.
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20
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Mahmoud NFH, Elsayed GA, Ismail MF. Synthesis of Various Fused Heterocyclic Rings from Oxoindenyl Esters and their Pharmacological and Antimicrobial Evaluations. J Heterocycl Chem 2017. [DOI: 10.1002/jhet.3065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Naglaa F. H. Mahmoud
- Chemistry Department, Faculty of Science; Ain Shams University; Abbassia Cairo 11566 Egypt
| | - Galal A. Elsayed
- Chemistry Department, Faculty of Science; Ain Shams University; Abbassia Cairo 11566 Egypt
| | - Mahmoud F. Ismail
- Chemistry Department, Faculty of Science; Ain Shams University; Abbassia Cairo 11566 Egypt
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21
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Wilson K, Webster SP, Iredale JP, Zheng X, Homer NZ, Pham NT, Auer M, Mole DJ. Detecting drug-target binding in cells using fluorescence-activated cell sorting coupled with mass spectrometry analysis. Methods Appl Fluoresc 2017; 6:015002. [PMID: 28901950 DOI: 10.1088/2050-6120/aa8c60] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The assessment of drug-target engagement for determining the efficacy of a compound inside cells remains challenging, particularly for difficult target proteins. Existing techniques are more suited to soluble protein targets. Difficult target proteins include those with challenging in vitro solubility, stability or purification properties that preclude target isolation. Here, we report a novel technique that measures intracellular compound-target complex formation, as well as cellular permeability, specificity and cytotoxicity-the toxicity-affinity-permeability-selectivity (TAPS) technique. The TAPS assay is exemplified here using human kynurenine 3-monooxygenase (KMO), a challenging intracellular membrane protein target of significant current interest. TAPS confirmed target binding of known KMO inhibitors inside cells. We conclude that the TAPS assay can be used to facilitate intracellular hit validation on most, if not all intracellular drug targets.
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Affiliation(s)
- Kris Wilson
- Drug Discovery Core, University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, United Kingdom
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22
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Jacobs KR, Castellano-Gonzalez G, Guillemin GJ, Lovejoy DB. Major Developments in the Design of Inhibitors along the Kynurenine Pathway. Curr Med Chem 2017; 24:2471-2495. [PMID: 28464785 PMCID: PMC5748880 DOI: 10.2174/0929867324666170502123114] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/13/2017] [Accepted: 04/18/2017] [Indexed: 12/20/2022]
Abstract
Disrupted kynurenine pathway (KP) metabolism has been implicated in the progression of neurodegenerative disease, psychiatric disorders and cancer. Modulation of enzyme activity along this pathway may therefore offer potential new therapeutic strategies for these conditions. Considering their prominent positions in the KP, the enzymes indoleamine 2,3-dioxygenase, kynurenine 3-monooxygenase and kynurenine aminotransferase, appear the most attractive targets. Already, increasing interest in this pathway has led to the identification of a number of potent and selective enzyme inhibitors with promising pre-clinical data and the elucidation of several enzyme crystal structures provides scope to rationalize the molecular mechanisms of inhibitor activity. The field seems poised to yield one or more inhibitors that should find clinical utility.
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Affiliation(s)
- Kelly R Jacobs
- Neuroinflammation Group, Department of Biomedical Research, Faculty of Medicine and Health Sciences, Macquarie University, Sydney. Australia
| | - Gloria Castellano-Gonzalez
- Neuroinflammation Group, Department of Biomedical Research, Faculty of Medicine and Health Sciences, Macquarie University, Sydney. Australia
| | - Gilles J Guillemin
- Department of Biomedical Research, Faculty of Medicine and Health Science, Macquarie University, 2 Technology Place, Sydney. Australia
| | - David B Lovejoy
- Department of Biomedical Research, Faculty of Medicine and Health Science, Macquarie University, 2 Technology Place, Sydney. Australia
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23
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Walker AL, Ancellin N, Beaufils B, Bergeal M, Binnie M, Bouillot A, Clapham D, Denis A, Haslam CP, Holmes DS, Hutchinson JP, Liddle J, McBride A, Mirguet O, Mowat CG, Rowland P, Tiberghien N, Trottet L, Uings I, Webster SP, Zheng X, Mole DJ. Development of a Series of Kynurenine 3-Monooxygenase Inhibitors Leading to a Clinical Candidate for the Treatment of Acute Pancreatitis. J Med Chem 2017; 60:3383-3404. [PMID: 28398044 DOI: 10.1021/acs.jmedchem.7b00055] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Recently, we reported a novel role for KMO in the pathogenesis of acute pancreatitis (AP). A number of inhibitors of kynurenine 3-monooxygenase (KMO) have previously been described as potential treatments for neurodegenerative conditions and particularly for Huntington's disease. However, the inhibitors reported to date have insufficient aqueous solubility relative to their cellular potency to be compatible with the intravenous (iv) dosing route required in AP. We have identified and optimized a novel series of high affinity KMO inhibitors with favorable physicochemical properties. The leading example is exquisitely selective, has low clearance in two species, prevents lung and kidney damage in a rat model of acute pancreatitis, and is progressing into preclinical development.
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Affiliation(s)
- Ann L Walker
- Discovery Partnerships with Academia, GlaxoSmithKline , Gunnels Wood Road, Stevenage SG1 2NY, UK
| | | | | | - Marylise Bergeal
- Platform Technology Sciences, GlaxoSmithKline Stevenage SG1 2NY, UK
| | - Margaret Binnie
- Centre for Cardiovascular Science, University of Edinburgh , Edinburgh EH16 4TJ, UK
| | - Anne Bouillot
- Flexible Discovery Unit, GlaxoSmithKline , Paris, France
| | - David Clapham
- Platform Technology Sciences, GlaxoSmithKline Stevenage SG1 2NY, UK
| | - Alexis Denis
- Flexible Discovery Unit, GlaxoSmithKline , Paris, France
| | - Carl P Haslam
- Platform Technology Sciences, GlaxoSmithKline Stevenage SG1 2NY, UK
| | - Duncan S Holmes
- Discovery Partnerships with Academia, GlaxoSmithKline , Gunnels Wood Road, Stevenage SG1 2NY, UK
| | | | - John Liddle
- Discovery Partnerships with Academia, GlaxoSmithKline , Gunnels Wood Road, Stevenage SG1 2NY, UK
| | - Andrew McBride
- Centre for Cardiovascular Science, University of Edinburgh , Edinburgh EH16 4TJ, UK
| | | | - Christopher G Mowat
- EastChem School of Chemistry, University of Edinburgh , Edinburgh EH9 3FJ, UK
| | - Paul Rowland
- Platform Technology Sciences, GlaxoSmithKline Stevenage SG1 2NY, UK
| | | | - Lionel Trottet
- Flexible Discovery Unit, GlaxoSmithKline , Paris, France
| | - Iain Uings
- Discovery Partnerships with Academia, GlaxoSmithKline , Gunnels Wood Road, Stevenage SG1 2NY, UK
| | - Scott P Webster
- Centre for Cardiovascular Science, University of Edinburgh , Edinburgh EH16 4TJ, UK
| | - Xiaozhong Zheng
- MRC Centre for Inflammation Research, University of Edinburgh , Edinburgh EH16 4TJ, UK
| | - Damian J Mole
- MRC Centre for Inflammation Research, University of Edinburgh , Edinburgh EH16 4TJ, UK
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24
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Liddle J, Beaufils B, Binnie M, Bouillot A, Denis AA, Hann MM, Haslam CP, Holmes DS, Hutchinson JP, Kranz M, McBride A, Mirguet O, Mole DJ, Mowat CG, Pal S, Rowland P, Trottet L, Uings IJ, Walker AL, Webster SP. The discovery of potent and selective kynurenine 3-monooxygenase inhibitors for the treatment of acute pancreatitis. Bioorg Med Chem Lett 2017; 27:2023-2028. [PMID: 28336141 DOI: 10.1016/j.bmcl.2017.02.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/21/2022]
Abstract
A series of potent, competitive and highly selective kynurenine monooxygenase inhibitors have been discovered via a substrate-based approach for the treatment of acute pancreatitis. The lead compound demonstrated good cellular potency and clear pharmacodynamic activity in vivo.
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Affiliation(s)
- John Liddle
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK.
| | | | - Margaret Binnie
- Centre for Cardiovascular Science, University of Edinburgh, UK
| | | | | | - Michael M Hann
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Carl P Haslam
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Duncan S Holmes
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Jon P Hutchinson
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Michael Kranz
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Andrew McBride
- Centre for Cardiovascular Science, University of Edinburgh, UK
| | | | - Damian J Mole
- MRC Centre for Inflammation Research, University of Edinburgh, UK
| | | | - Sandeep Pal
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Paul Rowland
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | | | - Iain J Uings
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Ann L Walker
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Scott P Webster
- Centre for Cardiovascular Science, University of Edinburgh, UK
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25
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Zádori D, Veres G, Szalárdy L, Klivényi P, Fülöp F, Toldi J, Vécsei L. Inhibitors of the kynurenine pathway as neurotherapeutics: a patent review (2012–2015). Expert Opin Ther Pat 2016; 26:815-32. [DOI: 10.1080/13543776.2016.1189531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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26
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Beaumont V, Mrzljak L, Dijkman U, Freije R, Heins M, Rassoulpour A, Tombaugh G, Gelman S, Bradaia A, Steidl E, Gleyzes M, Heikkinen T, Lehtimäki K, Puoliväli J, Kontkanen O, Javier RM, Neagoe I, Deisemann H, Winkler D, Ebneth A, Khetarpal V, Toledo-Sherman L, Dominguez C, Park LC, Munoz-Sanjuan I. The novel KMO inhibitor CHDI-340246 leads to a restoration of electrophysiological alterations in mouse models of Huntington's disease. Exp Neurol 2016; 282:99-118. [PMID: 27163548 DOI: 10.1016/j.expneurol.2016.05.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 04/28/2016] [Accepted: 05/05/2016] [Indexed: 11/18/2022]
Abstract
Dysregulation of the kynurenine (Kyn) pathway has been associated with the progression of Huntington's disease (HD). In particular, elevated levels of the kynurenine metabolites 3-hydroxy kynurenine (3-OH-Kyn) and quinolinic acid (Quin), have been reported in the brains of HD patients as well as in rodent models of HD. The production of these metabolites is controlled by the activity of kynurenine mono-oxygenase (KMO), an enzyme which catalyzes the synthesis of 3-OH-Kyn from Kyn. In order to determine the role of KMO in the phenotype of mouse models of HD, we have developed a potent and selective KMO inhibitor termed CHDI-340246. We show that this compound, when administered orally to transgenic mouse models of HD, potently and dose-dependently modulates the Kyn pathway in peripheral tissues and in the central nervous system. The administration of CHDI-340246 leads to an inhibition of the formation of 3-OH-Kyn and Quin, and to an elevation of Kyn and Kynurenic acid (KynA) levels in brain tissues. We show that administration of CHDI-340246 or of Kyn and of KynA can restore several electrophysiological alterations in mouse models of HD, both acutely and after chronic administration. However, using a comprehensive panel of behavioral tests, we demonstrate that the chronic dosing of a selective KMO inhibitor does not significantly modify behavioral phenotypes or natural progression in mouse models of HD.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Larry C Park
- CHDI Foundation/CHDI Management Inc., Los Angeles, USA
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27
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Khandaker GM, Dantzer R. Is there a role for immune-to-brain communication in schizophrenia? Psychopharmacology (Berl) 2016; 233:1559-73. [PMID: 26037944 PMCID: PMC4671307 DOI: 10.1007/s00213-015-3975-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/22/2015] [Indexed: 02/06/2023]
Abstract
Schizophrenia is characterised by hallucinations, delusions, depression-like so-called negative symptoms, cognitive dysfunction, impaired neurodevelopment and neurodegeneration. Epidemiological and genetic studies strongly indicate a role of inflammation and immunity in the pathogenesis of symptoms of schizophrenia. Evidence accrued over the last two decades has demonstrated that there are a number of pathways through which systemic inflammation can exert profound influence on the brain leading to changes in mood, cognition and behaviour. The peripheral immune system-to-brain communication pathways have been studied extensively in the context of depression where inflammatory cytokines are thought to play a key role. In this review, we highlight novel evidence suggesting an important role of peripheral immune-to-brain communication pathways in schizophrenia. We discuss recent population-based longitudinal studies that report an association between elevated levels of circulating inflammatory cytokines and subsequent risk of psychosis. We discuss emerging evidence indicating potentially important role of blood-brain barrier endothelial cells in peripheral immune-to-brain communication, which may be also relevant for schizophrenia. Drawing on clinical and preclinical studies, we discuss whether immune-mediated mechanisms could help to explain some of the clinical and pathophysiological features of schizophrenia. We discuss implication of these findings for approaches to diagnosis, treatment and research in future. Finally, pointing towards links with early-life adversity, we consider whether persistent low-grade activation of the innate immune response, as a result of impaired foetal or childhood development, could be a common mechanism underlying the high comorbidity between certain neuropsychiatric and physical illnesses, such as schizophrenia, depression, heart disease and type-two diabetes.
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Affiliation(s)
- Golam M Khandaker
- Department of Psychiatry, University of Cambridge, Box 189, Cambridge Biomedical Campus, Cambridge, CB2 2QQ, UK.
| | - Robert Dantzer
- Department of Symptom Research, Division of Internal Medicine, MD Anderson Cancer Center, Houston, TX, USA
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Pesek J, Svoboda J, Sattler M, Bartram S, Boland W. Biosynthesis of 8-hydroxyquinoline-2-carboxylic acid, an iron chelator from the gut of the lepidopteran Spodoptera littoralis. Org Biomol Chem 2015; 13:178-84. [PMID: 25356857 DOI: 10.1039/c4ob01857e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the regurgitate (foregut content) of Spodoptera larvae we found high concentrations (0.5-5 mM) of 8-hydroxyquinoline-2-carboxylic acid (8-HQA). In a survey of different lepidopteran species, this compound was only detected in species belonging to the family of Noctuidae. 8-HQA was shown to derive from tryptophan metabolism. The amount of 8-HQA in the regurgitate was strongly dependent on the tryptophan content of the diet. In the insect 8-HQA is generated from tryptophan via kynurenine and 3-hydroxykynurenine. 8-HQA is produced by the larvae and not by their commensal gut bacteria. Analysis of different life stages of Spodoptera larvae revealed that 8-HQA is formed during the larval stage, probably acting as an iron chelator to control the gut microbiome.
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Affiliation(s)
- Jelena Pesek
- Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany.
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29
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Inhibitors of quinolinic acid synthesis: new weapons in the study of neuroinflammatory diseases. Future Med Chem 2015; 6:841-3. [PMID: 24962274 DOI: 10.4155/fmc.14.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Wilson K, Mole DJ, Homer NZM, Iredale JP, Auer M, Webster SP. A magnetic bead-based ligand binding assay to facilitate human kynurenine 3-monooxygenase drug discovery. ACTA ACUST UNITED AC 2014; 20:292-8. [PMID: 25296660 DOI: 10.1177/1087057114554171] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human kynurenine 3-monooxygenase (KMO) is emerging as an important drug target enzyme in a number of inflammatory and neurodegenerative disease states. Recombinant protein production of KMO, and therefore discovery of KMO ligands, is challenging due to a large membrane targeting domain at the C-terminus of the enzyme that causes stability, solubility, and purification difficulties. The purpose of our investigation was to develop a suitable screening method for targeting human KMO and other similarly challenging drug targets. Here, we report the development of a magnetic bead-based binding assay using mass spectrometry detection for human KMO protein. The assay incorporates isolation of FLAG-tagged KMO enzyme on protein A magnetic beads. The protein-bound beads are incubated with potential binding compounds before specific cleavage of the protein-compound complexes from the beads. Mass spectrometry analysis is used to identify the compounds that demonstrate specific binding affinity for the target protein. The technique was validated using known inhibitors of KMO. This assay is a robust alternative to traditional ligand-binding assays for challenging protein targets, and it overcomes specific difficulties associated with isolating human KMO.
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Affiliation(s)
- Kris Wilson
- Drug Discovery Core, University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Damian J Mole
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Natalie Z M Homer
- Mass Spectrometry Core, Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - John P Iredale
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Manfred Auer
- School of Biological Sciences and School of Biomedical Sciences, University of Edinburgh, C H Waddington Building, The University of Edinburgh, Edinburgh, UK
| | - Scott P Webster
- Drug Discovery Core, University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
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31
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Stone TW, Darlington LG. The kynurenine pathway as a therapeutic target in cognitive and neurodegenerative disorders. Br J Pharmacol 2014; 169:1211-27. [PMID: 23647169 DOI: 10.1111/bph.12230] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/16/2013] [Accepted: 04/24/2013] [Indexed: 02/06/2023] Open
Abstract
Understanding the neurochemical basis for cognitive function is one of the major goals of neuroscience, with a potential impact on the diagnosis, prevention and treatment of a range of psychiatric and neurological disorders. In this review, the focus will be on a biochemical pathway that remains under-recognized in its implications for brain function, even though it can be responsible for moderating the activity of two neurotransmitters fundamentally involved in cognition - glutamate and acetylcholine. Since this pathway - the kynurenine pathway of tryptophan metabolism - is induced by immunological activation and stress, it also stands in a unique position to mediate the effects of environmental factors on cognition and behaviour. Targeting the pathway for new drug development could, therefore, be of value not only for the treatment of existing psychiatric conditions, but also for preventing the development of cognitive disorders in response to environmental pressures.
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Affiliation(s)
- Trevor W Stone
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.
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Abstract
Various pathologies of the central nervous system (CNS) are accompanied by alterations in tryptophan metabolism. The main metabolic route of tryptophan degradation is the kynurenine pathway; its metabolites are responsible for a broad spectrum of effects, including the endogenous regulation of neuronal excitability and the initiation of immune tolerance. This Review highlights the involvement of the kynurenine system in the pathology of neurodegenerative disorders, pain syndromes and autoimmune diseases through a detailed discussion of its potential implications in Huntington's disease, migraine and multiple sclerosis. The most effective preclinical drug candidates are discussed and attention is paid to currently under-investigated roles of the kynurenine pathway in the CNS, where modulation of kynurenine metabolism might be of therapeutic value.
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Feng Y, Bowden BF, Kapoor V. Ianthellamide A, a selective kynurenine-3-hydroxylase inhibitor from the Australian marine sponge Ianthella quadrangulata. Bioorg Med Chem Lett 2012; 22:3398-401. [PMID: 22525315 DOI: 10.1016/j.bmcl.2012.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/29/2012] [Accepted: 04/02/2012] [Indexed: 12/27/2022]
Abstract
Ianthellamide A (1), a novel octopamine derivative, was isolated from the Australian marine sponge Ianthella quadrangulata. Compound 1 selectively inhibited the activity of kynurenine 3-hydroxylase with an IC(50) value of 1.5 μM. It also significantly increased the level of endogenous kynurenic acid in rat brain and hence has the potential as a neuroprotective agent in the treatment of neurodegenerative disorders.
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Affiliation(s)
- Yunjiang Feng
- Eskitis Institute, Griffith University, Brisbane, QLD 4111, Australia.
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35
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Stone TW, Forrest CM, Darlington LG. Kynurenine pathway inhibition as a therapeutic strategy for neuroprotection. FEBS J 2012; 279:1386-97. [DOI: 10.1111/j.1742-4658.2012.08487.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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Maes M, Leonard BE, Myint AM, Kubera M, Verkerk R. The new '5-HT' hypothesis of depression: cell-mediated immune activation induces indoleamine 2,3-dioxygenase, which leads to lower plasma tryptophan and an increased synthesis of detrimental tryptophan catabolites (TRYCATs), both of which contribute to the onset of depression. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:702-21. [PMID: 21185346 DOI: 10.1016/j.pnpbp.2010.12.017] [Citation(s) in RCA: 463] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 12/07/2010] [Accepted: 12/16/2010] [Indexed: 02/07/2023]
Abstract
This paper reviews the body of evidence that not only tryptophan and consequent 5-HT depletion, but also induction of indoleamine 2,3-dioxygenase (IDO) and the detrimental effects of tryptophan catabolites (TRYCATs) play a role in the pathophysiology of depression. IDO is induced by interferon (IFN)γ, interleukin-6 and tumor necrosis factor-α, lipopolysaccharides and oxidative stress, factors that play a role in the pathophysiology of depression. TRYCATs, like kynurenine and quinolinic acid, are depressogenic and anxiogenic; activate oxidative pathways; cause mitochondrial dysfunctions; and have neuroexcitatory and neurotoxic effects that may lead to neurodegeneration. The TRYCAT pathway is also activated following induction of tryptophan 2,3-dioxygenase (TDO) by glucocorticoids, which are elevated in depression. There is evidence that activation of IDO reduces plasma tryptophan and increases TRYCAT synthesis in depressive states and that TDO activation may play a role as well. The development of depressive symptoms during IFNα-based immunotherapy is strongly associated with IDO activation, increased production of detrimental TRYCATs and lowered levels of tryptophan. Women show greater IDO activation and TRYCAT production following immune challenge than men. In the early puerperium, IDO activation and TRYCAT production are associated with the development of affective symptoms. Clinical depression is accompanied by lowered levels of neuroprotective TRYCATs or increased levels or neurotoxic TRYCATs, and lowered plasma tryptophan, which is associated with indices of immune activation and glucocorticoid hypersecretion. Lowered tryptophan and increased TRYCATs induce T cell unresponsiveness and therefore may exert a negative feedback on the primary inflammatory response in depression. It is concluded that activation of the TRYCAT pathway by IDO and TDO may be associated with the development of depressive symptoms through tryptophan depletion and the detrimental effects of TRYCATs. Therefore, the TRYCAT pathway should be a new drug target in depression. Direct inhibitors of IDO are less likely to be useful drugs than agents, such as kynurenine hydroxylase inhibitors; drugs which block the primary immune response; compounds that increase the protective effects of kynurenic acid; and specific antioxidants that target IDO activation, the immune and oxidative pathways, and 5-HT as well.
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Affiliation(s)
- M Maes
- Maes Clinics @ TRIA, Piyavate Hospital, 998 Rimklongsamsen Road, Bangkok 10310, Thailand.
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37
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Schwarcz R, Guidetti P, Sathyasaikumar KV, Muchowski PJ. Of mice, rats and men: Revisiting the quinolinic acid hypothesis of Huntington's disease. Prog Neurobiol 2010; 90:230-45. [PMID: 19394403 PMCID: PMC2829333 DOI: 10.1016/j.pneurobio.2009.04.005] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 04/17/2009] [Indexed: 12/31/2022]
Abstract
The neurodegenerative disease Huntington's disease (HD) is caused by an expanded polyglutamine (polyQ) tract in the protein huntingtin (htt). Although the gene encoding htt was identified and cloned more than 15 years ago, and in spite of impressive efforts to unravel the mechanism(s) by which mutant htt induces nerve cell death, these studies have so far not led to a good understanding of pathophysiology or an effective therapy. Set against a historical background, we review data supporting the idea that metabolites of the kynurenine pathway (KP) of tryptophan degradation provide a critical link between mutant htt and the pathophysiology of HD. New studies in HD brain and genetic model organisms suggest that the disease may in fact be causally related to early abnormalities in KP metabolism, favoring the formation of two neurotoxic metabolites, 3-hydroxykynurenine and quinolinic acid, over the related neuroprotective agent kynurenic acid. These findings not only link the excitotoxic hypothesis of HD pathology to an impairment of the KP but also define new drug targets and therefore have direct therapeutic implications. Thus, pharmacological normalization of the imbalance in brain KP metabolism may provide clinical benefits, which could be especially effective in early stages of the disease.
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Affiliation(s)
- Robert Schwarcz
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA.
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38
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Modulation of the Kynurenine Pathway for the Potential Treatment of Neurodegenerative Diseases. TOPICS IN MEDICINAL CHEMISTRY 2010. [DOI: 10.1007/7355_2010_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Mahmoud M, Shalaby A, Gad T, El-Khamry A. A facile synthesis and heteroannulation of pyrido[2,3-d]pyrimidine and related heterocyclic systems. JOURNAL OF CHEMICAL RESEARCH 2009. [DOI: 10.3184/030823409x12523324765777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
7-Amino-1,2,3,4-tetrahydro-4-oxo-2-thioxo-5-(3,4,5-trimethoxyphenyl)pyrido[2,3- d]pyrimidine (1) was prepared and reacted with methyl iodide and ethyl chloroacetate to give the S-alkylated products 2 and 3, respectively. The reaction of 1 or 3 with hydrazine hydrate yielded the same 2-hydrazino derivative 4. Treatment of 4 with 2,4-pentanedione, 2-acetylcyclohexanone and ethyl acetoacetate afforded the corresponding pyrazolylpyrido[2,3- d]pyrimidine derivatives (5–7), while phthalic anhydride gave the phthalazinyl compound 8. Ethoxymethylenemalononitrile with the hydrazine 4 formed the fused 1,2,4-triazepine 9, while triazolopyrido[2,3- d]pyrimidines were obtained from the reaction of 4 with benzylidene malononitrile or benzaldehyde (forming 10), acetic acid/anhydride (giving 11), and ethyl chloroformate (giving 12).
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Affiliation(s)
- M.R. Mahmoud
- Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt
| | - A.A. Shalaby
- Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt
| | - T.A. Gad
- Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt
| | - A.A. El-Khamry
- Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt
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40
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Costantino G. New promises for manipulation of kynurenine pathway in cancer and neurological diseases. Expert Opin Ther Targets 2009; 13:247-58. [PMID: 19236242 DOI: 10.1517/14728220802665734] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND The kynurenine pathway (KP), the primary route of tryptophan degradation in mammalian cells, consists of a cascade of enzymatic reactions eventually leading to NAD(+) formation. Many metabolites along the route have biological activities, especially in the nervous and immune systems. OBJECTIVE/METHODS This review focuses on three therapeutic areas, tumor immunoediting, schizophrenia, and Huntington's disease, apparently disconnected but linked by preliminary proof-of-concept of KP involvement. The potential embedded in drug discovery programs aimed at the identification of selective inhibitors with optimized pharmacodynamic and pharmacokinetic properties for human studies is discussed. RESULTS/CONCLUSIONS Recent advances have shifted the attention on the kynurenine pathway from a scientific curiosity to a clinically relevant collection of targets. A relatively large number of ligands able to interfere with individual enzymes of the pathway have been made available, but none have so far proceeded into advanced clinical studies.
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Affiliation(s)
- Gabriele Costantino
- Università degli Studi di Parma, Dipartimento Farmaceutico, Via GP Usberti 27/A-Campus Universitario, 43100 Parma, Italy.
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41
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Crozier-Reabe KR, Phillips RS, Moran GR. Kynurenine 3-monooxygenase from Pseudomonas fluorescens: substrate-like inhibitors both stimulate flavin reduction and stabilize the flavin-peroxo intermediate yet result in the production of hydrogen peroxide. Biochemistry 2009; 47:12420-33. [PMID: 18954092 DOI: 10.1021/bi8010434] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kynurenine 3-monooxygenase (KMO) is a flavin-dependent hydroxylase that catalyzes the conversion of l-kynurenine (l-Kyn) to 3-hydroxykynurenine (3OHKyn) in the pathway for tryptophan catabolism. KMO inhibition has been widely suggested as an early treatment for stroke and other neurological disorders that involve ischemia. We have investigated the reductive and the oxidative half-reactions of a stable form of KMO from Pseudomonas fluorescens (KMO). The binding of l-Kyn by the enzyme is relatively slow and involves at least two reversible steps. The rate constant for reduction of the flavin cofactor by NADPH increases by a factor of approximately 2.5 x 10(3) when l-Kyn is bound. The rate of reduction of the KMO.l-Kyn complex is 160 s(-1), and the K(d) for the NADPH complex is 200 microM with charge-transfer absorption bands for the KMO(RED).l-Kyn.NADP(+) complex accumulating after reduction. The reduction potential of KMO is -188 mV and is unresponsive to the addition of l-Kyn or other inhibitory ligands. KMO inhibitors whose structures are reminiscent of l-Kyn such as m-nitrobenzoylalanine and benzoylalanine also stimulate reduction of flavin by NADPH and, in the presence of dioxygen, result in the stoichiometric liberation of hydrogen peroxide, diminishing the perceived therapeutic potential of inhibitors of this type. In the presence of the native substrate, the oxidative half-reaction exhibits triphasic absorbance data. A spectrum consistent with that of a peroxyflavin species accumulates and then decays to yield the oxidized enzyme. This species then undergoes minor spectral changes that, based on flavin difference spectra defined in the presence of 3OHKyn, can be correlated with product release. The oxidative half-reaction observed in the presence of saturating benzoylalanine or m-nitrobenzoylalanine also shows the accumulation of a peroxyflavin species that then decays to yield hydrogen peroxide without hydroxylation.
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Affiliation(s)
- Karen R Crozier-Reabe
- Department of Chemistry and Biochemistry, University of Wisconsin, 3210 North Cramer Street, Milwaukee, Wisconsin 53211-3029, USA
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Chen Y, Guillemin GJ. Kynurenine pathway metabolites in humans: disease and healthy States. Int J Tryptophan Res 2009; 2:1-19. [PMID: 22084578 PMCID: PMC3195227 DOI: 10.4137/ijtr.s2097] [Citation(s) in RCA: 422] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Tryptophan is an essential amino acid that can be metabolised through different pathways, a major route being the kynurenine pathway. The first enzyme of the pathway, indoleamine-2,3-dioxygenase, is strongly stimulated by inflammatory molecules, particularly interferon gamma. Thus, the kynurenine pathway is often systematically up-regulated when the immune response is activated. The biological significance is that 1) the depletion of tryptophan and generation of kynurenines play a key modulatory role in the immune response; and 2) some of the kynurenines, such as quinolinic acid, 3-hydroxykynurenine and kynurenic acid, are neuroactive. The kynurenine pathway has been demonstrated to be involved in many diseases and disorders, including Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease, AIDS dementia complex, malaria, cancer, depression and schizophrenia, where imbalances in tryptophan and kynurenines have been found. This review compiles most of these studies and provides an overview of how the kynurenine pathway might be contributing to disease development, and the concentrations of tryptophan and kynurenines in the serum, cerebrospinal fluid and brain tissues in control and patient subjects.
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Affiliation(s)
- Yiquan Chen
- School of Medical Sciences, University of New South Wales, Sydney 2052, Australia
| | - Gilles J. Guillemin
- School of Medical Sciences, University of New South Wales, Sydney 2052, Australia
- St. Vincent’s Centre for Applied Medical Research, Darlinghurst 2010, Australia
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Rózsa E, Robotka H, Vécsei L, Toldi J. The Janus-face kynurenic acid. J Neural Transm (Vienna) 2008; 115:1087-91. [PMID: 18446262 DOI: 10.1007/s00702-008-0052-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 04/08/2008] [Indexed: 11/26/2022]
Abstract
Kynurenic acid is an endogenous product of the tryptophan metabolism. Studies on the mechanism of its action have revealed that kynurenic acid at high concentrations is a competitive antagonist of the N-methyl-D-aspartate receptor and acts as a neuroprotectant in different neurological disorders. This in vitro investigation was designed to show that kynurenic acid acts differently at low concentrations. In vitro electrophysiological examinations on the young rat hippocampus confirmed the well-known finding that kynurenic acid in micromolar concentrations exerts an inhibitory effect. However, in nanomolar concentrations, kynurenic acid does not give rise to inhibition, but in fact facilitates the field excitatory postsynaptic potentials. The results available so far are compatible with the idea that kynurenic acid in the concentration range between a few hundred nanomolar and micromolar displays different effects. Its probable action on different receptors, inducing the different mechanisms, is discussed. The findings strongly suggest the neuromodulatory role of kynurenic acid under both physiological and pathological circumstances.
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Affiliation(s)
- Eva Rózsa
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
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Abstract
L-kynurenine is an intermediate in the pathway of the metabolism of L-tryptophan to nicotinic acid. L-kynurenine is formed in the mammalian brain (40%) and is taken up from the periphery (60%), indicating that it can be transported across the BBB. It was discovered some 30 years ago that compounds in the kynurenine family have neuroactive properties. L-kynurenine, the central agent of this pathway, can be converted into two other important compounds: the neuroprotective kynurenic acid and the neurotoxic quinolinic acid. Kynurenines have been shown to be involved in many diverse physiological and pathological processes. There are a number of neurodegenerative disorders whose pathogenesis has been demonstrated to involve multiple imbalances of the kynurenine pathway metabolism. This review summarizes the main steps of the kynurenine pathway under normal conditions, discusses the metabolic disturbances and changes in this pathway in certain neurodegenerative disorders, and finally introduces the therapeutic possibilities with kynurenines.
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Affiliation(s)
- Hermina Robotka
- University of Szeged, Department of Physiology, Anatomy & Neuroscience, POB 533, and,Department of Neurology, POB 427, H-6701 Szeged, Hungary
| | - József Toldi
- University of Szeged, Department of Physiology, Anatomy & Neuroscience, POB 533, H-6701 Szeged, Hungary
| | - László Vécsei
- University of Szeged, Department of Neurology, POB 427, H-6701 Szeged, Hungary
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45
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Han Q, Robinson H, Li J. Crystal structure of human kynurenine aminotransferase II. J Biol Chem 2007; 283:3567-3573. [PMID: 18056995 DOI: 10.1074/jbc.m708358200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Human kynurenine aminotransferase II (hKAT-II) efficiently catalyzes the transamination of knunrenine to kynurenic acid (KYNA). KYNA is the only known endogenous antagonist of N-methyl-D-aspartate (NMDA) receptors and is also an antagonist of 7-nicotinic acetylcholine receptors. Abnormal concentrations of brain KYNA have been implicated in the pathogenesis and development of several neurological and psychiatric diseases in humans. Consequently, enzymes involved in the production of brain KYNA have been considered potential regulatory targets. In this article, we report a 2.16 A crystal structure of hKAT-II and a 1.95 A structure of its complex with kynurenine. The protein architecture of hKAT-II reveals that it belongs to the fold-type I pyridoxal 5-phosphate (PLP)-dependent enzymes. In comparison with all subclasses of fold-type I-PLP-dependent enzymes, we propose that hKAT-II represents a novel subclass in the fold-type I enzymes because of the unique folding of its first 65 N-terminal residues. This study provides a molecular basis for future effort in maintaining physiological concentrations of KYNA through molecular and biochemical regulation of hKAT-II.
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Affiliation(s)
- Qian Han
- Department of Biochemistry, Virginia Tech University, Blacksburg, Virginia 24061
| | - Howard Robinson
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Jianyong Li
- Department of Biochemistry, Virginia Tech University, Blacksburg, Virginia 24061.
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Mahmoud MR, El-Bordany EAA, Hassan NF, Abu El-Azm FSM. Utility of Nitriles in Synthesis of Pyrido[2,3-d]pyrimidines, Thiazolo[3,2-a]pyridines, Pyrano[2,3-b]benzopyrrole, and Pyrido[2,3-d]benzopyrroles. PHOSPHORUS SULFUR 2007. [DOI: 10.1080/10426500701506465] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- M. R. Mahmoud
- a Chemistry Department, Faculty of Science , Ain Shams University , Cairo , Egypt
| | - E. A. A. El-Bordany
- a Chemistry Department, Faculty of Science , Ain Shams University , Cairo , Egypt
| | - N. F. Hassan
- a Chemistry Department, Faculty of Science , Ain Shams University , Cairo , Egypt
| | - F. S. M. Abu El-Azm
- a Chemistry Department, Faculty of Science , Ain Shams University , Cairo , Egypt
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47
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Mahmoud MR, El-Bordany EA, Azab ME, Soliman EA. Synthesis of New Thiadiazoles, 1,2,4-Triazolo[3,4-b]-1,3,4-thiadiazoles, and 1,2,4-Triazolo[2,3-c]quinazoline Derivatives from 3,1-Benzoxazin(4H)-one Derivative. PHOSPHORUS SULFUR 2007. [DOI: 10.1080/10426500601160785] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- M. R. Mahmoud
- a Chemistry Department , Ain Shams University , Cairo , Egypt
| | | | - M. E. Azab
- a Chemistry Department , Ain Shams University , Cairo , Egypt
| | - E. A. Soliman
- a Chemistry Department , Ain Shams University , Cairo , Egypt
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48
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Ceresoli-Borroni G, Guidetti P, Amori L, Pellicciari R, Schwarcz R. Perinatal kynurenine 3-hydroxylase inhibition in rodents: pathophysiological implications. J Neurosci Res 2007; 85:845-54. [PMID: 17279543 DOI: 10.1002/jnr.21183] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The kynurenine pathway (KP) of tryptophan degradation contains three neuroactive metabolites: the neuroinhibitory agent kynurenic acid (KYNA) and, in a competing branch, the free radical generator 3-hydroxykynurenine (3-HK) and the excitotoxin quinolinic acid (QUIN). These three "kynurenines" derive from a common precursor, L-kynurenine, and are recognized for their role in brain physiology and pathophysiology. Inhibition of kynurenine 3-hydroxylase, the enzyme responsible for 3-HK formation, shifts KP metabolism in the mature brain toward enhanced KYNA formation. We now tested the cerebral effects of kynurenine 3-hydroxylase inhibition in immature rodents. Rat pups treated with the kynurenine 3-hydroxylase inhibitor UPF 648 (30 mg/kg, i.p.) 10 min after birth showed substantial increases in cerebral and liver kynurenine and KYNA levels up to 24 hr later, whereas 3-HK and QUIN levels were simultaneously decreased. Administered to pregnant rats or mice on the last day of gestation, UPF 648 (50 mg/kg, i.p.) produced qualitatively similar changes (i.e., large increases in kynurenine and KYNA and reductions in 3-HK and QUIN) in the brain and liver of the offspring. Rat pups delivered by UPF 648-treated mothers and immediately exposed to neonatal asphyxia showed further enhanced brain KYNA levels. These studies demonstrate that acute kynurenine 3-hydroxylase inhibition effectively shifts cerebral KP metabolism in neonatal rodents toward increased KYNA formation. Selective inhibitors of this enzyme may therefore provide neuroprotection in newborns and will also be useful for the experimental evaluation of the long-term effects of perinatal KP impairment.
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Affiliation(s)
- Gianpiera Ceresoli-Borroni
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland 21228, USA
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49
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Guidetti P, Hoffman GE, Melendez-Ferro M, Albuquerque EX, Schwarcz R. Astrocytic localization of kynurenine aminotransferase II in the rat brain visualized by immunocytochemistry. Glia 2007; 55:78-92. [PMID: 17024659 DOI: 10.1002/glia.20432] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Kynurenic acid (KYNA), a metabolite of the kynurenine pathway of tryptophan degradation, is a neuroinhibitory agent present in the mammalian brain. Endogenous KYNA preferentially affects the alpha7 nicotinic acetylcholine (alpha7nACh) receptor and, possibly, the glycine co-agonist (glycineB) site of the NMDA receptor. Functionally relevant fluctuations in brain KYNA occur under both physiological and pathological conditions, affecting cholinergic and glutamatergic neurotransmission. Kynurenine aminotransferase II (KAT II), the major biosynthetic enzyme of KYNA in the rat brain, catalyzes the irreversible formation of KYNA from its immediate bioprecursor, kynurenine. We now purified rat kidney KAT II to homogeneity, generated a polyclonal rabbit anti-rat KAT II antibody, and purified the antibody using routine biochemical methods. The antibody selectively recognized KAT II by Western blot analysis and in immunotitration experiments. Used for immunocytochemistry, the antibody revealed discrete, specific staining of KAT II-positive astrocyte-like cells throughout the adult rat brain. The presence of KAT II in astrocytes was confirmed by double fluorescence immunostaining with an antibody against the astrocyte-specific marker glial fibrillary acidic protein (GFAP). No specific labeling was detected in neurons or microglia. However, KAT II-positive astrocytes were intimately associated with select neuron populations, supporting a neuromodulatory role of KYNA. Intense staining was frequently seen around brain capillaries, with astrocytic end feet contacting the capillary wall. This may explain the rapid access of blood-derived kynurenine to KAT II-containing astrocytes. The new anti-KAT II antibody should be useful in the further elucidation of the presumed role of KYNA in brain physiology and pathology.
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Affiliation(s)
- Paolo Guidetti
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland 21228, USA
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Luccini E, Musante V, Neri E, Raiteri M, Pittaluga A. N-methyl-D-aspartate autoreceptors respond to low and high agonist concentrations by facilitating, respectively, exocytosis and carrier-mediated release of glutamate in rat hippocampus. J Neurosci Res 2007; 85:3657-65. [PMID: 17671992 DOI: 10.1002/jnr.21446] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Presynaptic NMDA autoreceptors regulating glutamate release have rarely been investigated. High-micromolar N-methyl-D-aspartate (NMDA) was reported to elicit glutamate release from hippocampal synaptosomes in a Ca(2+)-independent manner by reversal of excitatory amino acid transporters. The aim of this work was to characterize excitatory amino acid release evoked by low-micromolar NMDA from glutamatergic axon terminals. Purified rat hippocampal synaptosomes were prelabelled with [(3)H]D-aspartate ([(3)H]D-ASP) and exposed in superfusion to varying concentrations of NMDA in the presence of 1 microM glycine. The release of [(3)H]D-ASP and also that of endogenous glutamate provoked by 10 microM NMDA were external Ca(2+) dependent and sensitive to the NMDA channel blocker MK-801 but insensitive to the glutamate transporter inhibitor DL-TBOA, which, on the contrary, prevented the Ca(2+)-independent release evoked by 100 microM NMDA. The NMDA (10 microM) response was blocked by 1 nM Zn(2+) and 1 microM ifenprodil, compatible with the involvement of a NR1/NR2A/NR2B assembly, although the presence of two separate receptor populations, i.e., NR1/NR2A and NR1/NR2B, cannot be excluded. This response was strongly antagonized by submicromolar (0.01-1 microM) concentrations of kynurenic acid and was mimicked by quinolinic acid (1-100 microM) plus 1 microM glycine. Finally, the HIV-1 protein gp120 potently mimicked the NMDA co-agonists glycine and D-serine, being significantly effective at 30 pM. In conclusion, glutamatergic nerve terminals possess NMDA autoreceptors mediating different types of release when activated by different agonist concentrations: low-micromolar glutamate would potentiate glutamate exocytosis, whereas higher glutamate concentrations would also provoke carrier-mediated release.
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Affiliation(s)
- Elisa Luccini
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genoa, Viale Cembrano 4, Genoa, Italy
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