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Relationships of Ischemic Stroke Occurrence and Outcome with Gene Variants Encoding Enzymes of Tryptophan Metabolism. Biomedicines 2021; 9:biomedicines9101441. [PMID: 34680558 PMCID: PMC8533114 DOI: 10.3390/biomedicines9101441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/29/2021] [Accepted: 10/02/2021] [Indexed: 12/29/2022] Open
Abstract
Ischemic stroke is among the leading causes of mortality and long-term disability worldwide. Among stroke risk factors the importance of genetic background is gaining interest. There is a growing body of evidence of changes of metabolite levels and enzyme activities involved in the conversion of Trp during the course of cerebral ischemia. We compared the frequencies of ten SNPs of five genes related to Trp metabolism between groups of 122 ischemic stroke patients and 120 control individuals. Furthermore, we examined the mRNA levels of TPH1, IDO1 and KYAT1 genes in peripheral venous blood with the aim of assessing (i) whether there are changes in their expression during the course of stroke and (ii) does any of their investigated SNPs have an impact on gene expression. In seven cases out of ten studied polymorphisms we detected significant differences in frequencies in relation to ischemic stroke occurrence, etiology, and clinical parameters. We also detected changes in the expression of TPH1 and IDO1 genes during the course of the disease. We found that those IDO1 variants which show a trend towards elevated mRNA level are more frequent in stroke patients than in controls. Our results are important novel observations which suggest a causal relationship between elevated IDO1 expression and stroke etiology.
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Bai MY, Lovejoy DB, Guillemin GJ, Kozak R, Stone TW, Koola MM. Galantamine-Memantine Combination and Kynurenine Pathway Enzyme Inhibitors in the Treatment of Neuropsychiatric Disorders. Complex Psychiatry 2021; 7:19-33. [PMID: 35141700 PMCID: PMC8443947 DOI: 10.1159/000515066] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/04/2021] [Indexed: 12/25/2022] Open
Abstract
The kynurenine pathway (KP) is a major route for L-tryptophan (L-TRP) metabolism, yielding a variety of bioactive compounds including kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), quinolinic acid (QUIN), and picolinic acid (PIC). These tryptophan catabolites are involved in the pathogenesis of many neuropsychiatric disorders, particularly when the KP becomes dysregulated. Accordingly, the enzymes that regulate the KP such as indoleamine 2,3-dioxygenase (IDO)/tryptophan 2,3-dioxygenase, kynurenine aminotransferases (KATs), and kynurenine 3-monooxygenase (KMO) represent potential drug targets as enzymatic inhibition can favorably rebalance KP metabolite concentrations. In addition, the galantamine-memantine combination, through its modulatory effects at the alpha7 nicotinic acetylcholine receptors and N-methyl-D-aspartate receptors, may counteract the effects of KYNA. The aim of this review is to highlight the effectiveness of IDO-1, KAT II, and KMO inhibitors, as well as the galantamine-memantine combination in the modulation of different KP metabolites. KAT II inhibitors are capable of decreasing the KYNA levels in the rat brain by a maximum of 80%. KMO inhibitors effectively reduce the central nervous system (CNS) levels of 3-HK, while markedly boosting the brain concentration of KYNA. Emerging data suggest that the galantamine-memantine combination also lowers L-TRP, kynurenine, KYNA, and PIC levels in humans. Presently, there are only 2 pathophysiological mechanisms (cholinergic and glutamatergic) that are FDA approved for the treatment of cognitive dysfunction for which purpose the galantamine-memantine combination has been designed for clinical use against Alzheimer's disease. The alpha7 nicotinic-NMDA hypothesis targeted by the galantamine-memantine combination has been implicated in the pathophysiology of various CNS diseases. Similarly, KYNA is well capable of modulating the neuropathophysiology of these disorders. This is known as the KYNA-centric hypothesis, which may be implicated in the management of certain neuropsychiatric conditions. In line with this hypothesis, KYNA may be considered as the "conductor of the orchestra" for the major pathophysiological mechanisms underlying CNS disorders. Therefore, there is great opportunity to further explore and compare the biological effects of these therapeutic modalities in animal models with a special focus on their effects on KP metabolites in the CNS and with the ultimate goal of progressing to clinical trials for many neuropsychiatric diseases.
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Affiliation(s)
- Michael Y. Bai
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David B. Lovejoy
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Gilles J. Guillemin
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Rouba Kozak
- Neuroscience Drug Discovery Unit, Takeda Pharmaceuticals International Co, Cambridge, Massachusetts, USA
| | - Trevor W. Stone
- Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Maju Mathew Koola
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, Stony Brook, New York, USA
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Abstract
The efficacious dose of a drug is perhaps the most holistic metric reflecting its therapeutic potential. Dose is predicted at many stages in drug discovery and development. Prior to the 1990s, dose prediction was limited to the drug "working" at a reasonable dose and dose regimen in an animal model. Through the early 2000s, dose predictions were generated at candidate nomination and then refined during clinical development. Currently, dose predictions can be made early in drug discovery to enable drug design. Dose predictions at this stage can identify critical drug properties for a viable dose regimen and provide clinically relevant context to lead optimization. In this paper, we give an overview of the opportunities and challenges associated with dose prediction for drug design. A number of general considerations, approaches, and case examples are discussed.
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Affiliation(s)
- Tristan S Maurer
- Medicine Design, Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139, United States
| | | | - Kevin Beaumont
- Medicine Design, Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139, United States
| | - Li Di
- Medicine Design, Pfizer Worldwide Research and Development, Groton, Connecticut 06340, United States
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Rossi F, Miggiano R, Ferraris DM, Rizzi M. The Synthesis of Kynurenic Acid in Mammals: An Updated Kynurenine Aminotransferase Structural KATalogue. Front Mol Biosci 2019; 6:7. [PMID: 30873412 PMCID: PMC6400995 DOI: 10.3389/fmolb.2019.00007] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 02/06/2019] [Indexed: 01/25/2023] Open
Abstract
Kynurenic acid (KYNA) is a bioactive compound that is produced along the kynurenine pathway (KP) during tryptophan degradation. In a few decades, KYNA shifted from being regarded a poorly characterized by-product of the KP to being considered a main player in many aspects of mammalian physiology, including the control of glutamatergic and cholinergic synaptic transmission, and the coordination of immunomodulation. The renewed attention being paid to the study of KYNA homeostasis is justified by the discovery of selective and potent inhibitors of kynurenine aminotransferase II, which is considered the main enzyme responsible for KYNA synthesis in the mammalian brain. Since abnormally high KYNA levels in the central nervous system have been associated with schizophrenia and cognitive impairment, these inhibitors promise the development of novel anti-psychotic and pro-cognitive drugs. Here, we summarize the currently available structural information on human and rodent kynurenine aminotransferases (KATs) as the result of global efforts aimed at describing the full complement of mammalian isozymes. These studies highlight peculiar features of KATs that can be exploited for the development of isozyme-specific inhibitors. Together with the optimization of biochemical assays to measure individual KAT activities in complex samples, this wealth of knowledge will continue to foster the identification and rational design of brain penetrant small molecules to attenuate KYNA synthesis, i.e., molecules capable of lowering KYNA levels without exposing the brain to the harmful withdrawal of KYNA-dependent neuroprotective actions.
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Affiliation(s)
- Franca Rossi
- Biochemistry and Biocrystallography Unit, DSF-Dipartimento di Scienze del Farmaco, University of Piemonte Orientale, Novara, Italy
| | - Riccardo Miggiano
- Biochemistry and Biocrystallography Unit, DSF-Dipartimento di Scienze del Farmaco, University of Piemonte Orientale, Novara, Italy
| | - Davide M Ferraris
- Biochemistry and Biocrystallography Unit, DSF-Dipartimento di Scienze del Farmaco, University of Piemonte Orientale, Novara, Italy
| | - Menico Rizzi
- Biochemistry and Biocrystallography Unit, DSF-Dipartimento di Scienze del Farmaco, University of Piemonte Orientale, Novara, Italy
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Pocivavsek A, Elmer GI, Schwarcz R. Inhibition of kynurenine aminotransferase II attenuates hippocampus-dependent memory deficit in adult rats treated prenatally with kynurenine. Hippocampus 2018; 29:73-77. [PMID: 30311334 DOI: 10.1002/hipo.23040] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/01/2018] [Accepted: 10/07/2018] [Indexed: 11/11/2022]
Abstract
A combination of genetic and environmental factors contributes to schizophrenia (SZ), a catastrophic psychiatric disorder with a hypothesized neurodevelopmental origin. Increases in the brain levels of the tryptophan metabolite kynurenic acid (KYNA), an endogenous antagonist of α7 nicotinic acetylcholine and NMDA receptors, have been implicated specifically in the cognitive deficits seen in persons with SZ. Here we evaluated this role of KYNA by adding the KYNA precursor kynurenine (100 mg/day) to chow fed to pregnant rat dams from embryonic day (ED) 15 to ED 22 (control: ECon; kynurenine treated: EKyn). Upon termination of the treatment, all rats received normal rodent chow until the animals were evaluated in adulthood (postnatal days 56-85). EKyn treatment resulted in increased extracellular KYNA and reduced extracellular glutamate in the hippocampus, measured by in vivo microdialysis, and caused impairments in hippocampus-dependent learning in adult rats. Acute administration of BFF816, a systemically active inhibitor of kynurenine aminotransferase II (KAT II), the major KYNA-synthesizing enzyme in the brain, normalized neurochemistry and prevented contextual memory deficits in adult EKyn animals. Collectively, these results demonstrate that acute inhibition of KYNA neosynthesis can overcome cognitive impairments that arise as a consequence of elevated brain KYNA in early brain development.
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Affiliation(s)
- Ana Pocivavsek
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Greg I Elmer
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
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