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Turska-Kozłowska M, Pedraz-Petrozzi B, Paluszkiewicz P, Parada-Turska J. Different Kynurenine Pathway Dysregulation in Systemic Sclerosis in Men and Women. Int J Mol Sci 2024; 25:3842. [PMID: 38612652 PMCID: PMC11011858 DOI: 10.3390/ijms25073842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/17/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
Systemic sclerosis (SSc), a predominantly female-affected systemic autoimmune disease, requires tailored treatment strategies contingent on organ involvement and symptom severity. Given SSc's inflammatory nature, the involvement of the kynurenine pathway (KP) in its pathophysiology is underexplored. Our study aimed to investigate sex-related differences in KP activation among SSc patients and assess the impact of angiotensin-converting enzyme (ACE) inhibitors and estimated glomerular filtration rate (eGFR) on KP metabolite concentrations. We enrolled 48 SSc patients and 53 healthy controls, quantifying KP metabolites (tryptophan (TRP), kynurenine (KYN), and kynurenic acid (KYNA)) in serum via high-performance liquid chromatography. Separate multivariate analyses of covariance (MANCOVAs) for women and men were performed to ascertain mean differences between patients and healthy controls while correcting for age. For our secondary objective, we conducted a MANCOVA to explore disparities in ACE inhibitor users and non-users among patients, with BMI correction. Our findings revealed decreased TRP concentrations but increased KYNA/TRP ratio and KYN/TRP ratio in both male and female SSc patients compared to their respective controls. Unlike women, SSc males exhibited higher KYN concentrations and decreased KYNA/KYN ratio relative to their controls. Additionally, SSc patients using ACE inhibitors had higher serum KYNA levels than non-users. Notably, we established a significant correlation between eGFR and KYNA in SSc patients. These results indicate differential KP activation in male and female SSc patients, with males demonstrating heightened KP activation. While ACE inhibitors may influence the KP in SSc patients, further research is necessary to comprehensively understand their impact on symptoms and prognosis in the context of these KP alterations.
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Affiliation(s)
- Monika Turska-Kozłowska
- Department of Molecular Biology, The John Paul II Catholic University of Lublin, Konstantynow 1H, 20-708 Lublin, Poland
| | - Bruno Pedraz-Petrozzi
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany;
| | - Piotr Paluszkiewicz
- Department of General, Oncological and Metabolic Surgery, Institute of Hematology and Transfusion Medicine, Indiry Gandhi 14, 02-778 Warsaw, Poland;
| | - Jolanta Parada-Turska
- Department of Rheumatology and Connective Tissue Diseases, Medical University of Lublin, Jaczewskiego 8, 20-090 Lublin, Poland;
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Kushibiki H, Mizukami H, Osonoi S, Takeuchi Y, Sasaki T, Ogasawara S, Wada K, Midorikawa S, Ryuzaki M, Wang Z, Yamada T, Yamazaki K, Tarusawa T, Tanba T, Mikami T, Matsubara A, Ishibashi Y, Hakamada K, Nakaji S. Tryptophan metabolism and small fibre neuropathy: a correlation study. Brain Commun 2024; 6:fcae103. [PMID: 38618209 PMCID: PMC11010654 DOI: 10.1093/braincomms/fcae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 01/10/2024] [Accepted: 03/24/2024] [Indexed: 04/16/2024] Open
Abstract
Small nerve fibres located in the epidermis sense pain. Dysfunction of these fibres decreases the pain threshold known as small fibre neuropathy. Diabetes mellitus is accompanied by metabolic changes other than glucose, synergistically eliciting small fibre neuropathy. These findings suggest that various metabolic changes may be involved in small fibre neuropathy. Herein, we explored the correlation between pain sensation and changes in plasma metabolites in healthy Japanese subjects. The pain threshold evaluated from the intraepidermal electrical stimulation was used to quantify pain sensation in a total of 1021 individuals in the 2017 Iwaki Health Promotion Project. Participants with a pain threshold evaluated from the intraepidermal electrical stimulation index <0.20 mA were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-low group (n = 751); otherwise, they were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-high group (n = 270). Metabolome analysis of plasma was conducted using capillary electrophoresis time-of-flight mass spectrometry. The metabolite set enrichment analysis revealed that the metabolism of tryptophan was significantly correlated with the pain threshold evaluated from the intraepidermal electrical stimulation index in all participants (P < 0.05). The normalized level of tryptophan was significantly decreased in participants with a high pain threshold evaluated from the intraepidermal electrical stimulation index. In addition to univariate linear regression analyses, the correlation between tryptophan concentration and the pain threshold evaluated from the intraepidermal electrical stimulation index remained significant after adjustment for multiple factors (β = -0.07615, P < 0.05). These findings indicate that specific metabolic changes are involved in the deterioration of pain thresholds. Here, we show that abnormal tryptophan metabolism is significantly correlated with an elevated pain threshold evaluated from the intraepidermal electrical stimulation index in the Japanese population. This correlation provides insight into the pathology and clinical application of small fibre neuropathy.
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Affiliation(s)
- Hanae Kushibiki
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Sho Osonoi
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Yuki Takeuchi
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Takanori Sasaki
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Saori Ogasawara
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Kanichiro Wada
- Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Shin Midorikawa
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Otorhinolaryngology-Head and Neck Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Masaki Ryuzaki
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Zhenchao Wang
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Takahiro Yamada
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Gastroenterological Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Keisuke Yamazaki
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Gastroenterological Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Takefusa Tarusawa
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Taiyo Tanba
- Department of Pathology and Molecular Medicine, Biomedical Research Center, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Gastroenterological Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Tatsuya Mikami
- Innovation Center for Health Promotion, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Atsushi Matsubara
- Department of Otorhinolaryngology-Head and Neck Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Yasuyuki Ishibashi
- Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Kenichi Hakamada
- Department of Gastroenterological Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Shigeyuki Nakaji
- Department of Social Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
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Pearson K, Beier K, Mardis T, Munoz B, Zaidi A. The Neurochemistry of Depression: The Good, The Bad and The Ugly. MISSOURI MEDICINE 2024; 121:68-75. [PMID: 38404431 PMCID: PMC10887465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A large constellation of experimental evidence suggests that neuroinflammation is involved in the onset of depression and neurodegenerative disorders. Many studies have shown impairments in tryptophan metabolism, the major pathway for the synthesis of serotonin, the mood regulating neurotransmitter. This article reviews the various metabolites generated in the competing pathways of tryptophan metabolism including the kynurenine pathway. Increased synthesis of the neurotoxic compound quinolinic acid occurs at the expense of the synthesis of the neuroprotective metabolite kynurenic acid. This shift in equilibrium plays a critical role in the induction of oxidative stress, neuroinflammation, and neurotoxicity. Sufficient protein intake with adequate amounts of tryptophan along with dietary antioxidants and flavonoids may offer protection against major depressive and neurodegenerative disorders.
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Affiliation(s)
- Kami Pearson
- Research Associate, Kansas City University, Kansas City, Missouri
| | - Kimberley Beier
- Medical student, Kansas City University, Kansas City, Missouri
| | - Thornton Mardis
- Medical student, Kansas City University, Kansas City, Missouri
| | - Bryan Munoz
- Medical student, Kansas City University, Kansas City, Missouri
| | - Asma Zaidi
- Professor of Biochemistry, Kansas City University, Kansas City, Missouri
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Stone TW, Williams RO. Tryptophan metabolism as a 'reflex' feature of neuroimmune communication: Sensor and effector functions for the indoleamine-2, 3-dioxygenase kynurenine pathway. J Neurochem 2023. [PMID: 38102897 DOI: 10.1111/jnc.16015] [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: 08/08/2023] [Revised: 10/16/2023] [Accepted: 11/08/2023] [Indexed: 12/17/2023]
Abstract
Although the central nervous system (CNS) and immune system were regarded as independent entities, it is now clear that immune system cells can influence the CNS, and neuroglial activity influences the immune system. Despite the many clinical implications for this 'neuroimmune interface', its detailed operation at the molecular level remains unclear. This narrative review focuses on the metabolism of tryptophan along the kynurenine pathway, since its products have critical actions in both the nervous and immune systems, placing it in a unique position to influence neuroimmune communication. In particular, since the kynurenine pathway is activated by pro-inflammatory mediators, it is proposed that physical and psychological stressors are the stimuli of an organismal protective reflex, with kynurenine metabolites as the effector arm co-ordinating protective neural and immune system responses. After a brief review of the neuroimmune interface, the general perception of tryptophan metabolism along the kynurenine pathway is expanded to emphasize this environmentally driven perspective. The initial enzymes in the kynurenine pathway include indoleamine-2,3-dioxygenase (IDO1), which is induced by tissue damage, inflammatory mediators or microbial products, and tryptophan-2,3-dioxygenase (TDO), which is induced by stress-induced glucocorticoids. In the immune system, kynurenic acid modulates leucocyte differentiation, inflammatory balance and immune tolerance by activating aryl hydrocarbon receptors and modulates pain via the GPR35 protein. In the CNS, quinolinic acid activates N-methyl-D-aspartate (NMDA)-sensitive glutamate receptors, whereas kynurenic acid is an antagonist: the balance between glutamate, quinolinic acid and kynurenic acid is a significant regulator of CNS function and plasticity. The concept of kynurenine and its metabolites as mediators of a reflex coordinated protection against stress helps to understand the variety and breadth of their activity. It should also help to understand the pathological origin of some psychiatric and neurodegenerative diseases involving the immune system and CNS, facilitating the development of new pharmacological strategies for treatment.
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Affiliation(s)
- Trevor W Stone
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford, UK
| | - Richard O Williams
- The Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Oxford, UK
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Gusdon AM, Savarraj JP, Feng D, Starkman A, Li G, Bodanapally U, Zimmerman WD, Ryan AS, Choi HA, Badjatia N. High-Protein Supplementation and Neuromuscular Electric Stimulation after Aneurysmal Subarachnoid Hemorrhage Increases Systemic Amino Acid and Oxidative Metabolism: A Plasma Metabolomics Approach. RESEARCH SQUARE 2023:rs.3.rs-3600439. [PMID: 38014126 PMCID: PMC10680941 DOI: 10.21203/rs.3.rs-3600439/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Background The INSPIRE randomized clinical trial demonstrated that a high protein diet (HPRO) combined with neuromuscular electrical stimulation (NMES) attenuates muscle atrophy and may improve functional outcomes after aSAH. Using an untargeted metabolomics approach, we sought to identify specific metabolites mediating these effects. Methods Blood samples were collected from subjects on admission prior to randomization to either standard of care (SOC; N=12) or HPRO+NMES (N=12) and at 7 days as part of the INSPIRE protocol. Untargeted metabolomics were performed for each plasma sample. Paired fold changes were calculated for each metabolite among subjects in the HPRO+NMES group at baseline and 7 days after intervention. Changes in metabolites from baseline to 7 days were compared for the HPRO+NMES and SOC groups. Sparse partial least squared discriminant analysis (sPLS-DA) identified metabolites discriminating each group. Pearson's correlation coefficients were calculated between each metabolite and total protein per day, nitrogen balance, and muscle volume Multivariable models were developed to determine associations between each metabolite and muscle volume. Results A total of 18 unique metabolites were identified including pre and post treatment and differentiating SOC vs HPRO+NMES. Of these, 9 had significant positive correlations with protein intake: N-acetylserine (ρ=0.61, P =1.56x10 -3 ), N-acetylleucine (ρ=0.58, P =2.97x10 -3 ), β-hydroxyisovaleroylcarnitine (ρ=0.53, P =8.35x10 -3 ), tiglyl carnitine (ρ=0.48, P =0.0168), N-acetylisoleucine (ρ=0.48, P =0.0183), N-acetylthreonine (ρ=0.47, P =0.0218), N-acetylkynurenine (ρ=0.45, P =0.0263), N-acetylvaline (ρ=0.44, P =0.0306), and urea (ρ=0.43, P =0.0381). In multivariable regression models, N-acetylleucine was significantly associated with preserved temporalis [OR 1.08 (95%CI 1.01, 1.16)] and quadricep [OR 1.08 (95%CI 1.02, 1.15)] muscle volume. Quinolinate was also significantly associated with preserved temporalis [OR 1.05 (95%CI 1.01, 1.09)] and quadricep [OR 1.04 (95%CI 1.00, 1.07)] muscle volume. N-acetylserine, N-acetylcitrulline, and b-hydroxyisovaleroylcarnitine were also associated with preserved temporalis or quadricep volume. Conclusions Metabolites defining the HPRO+NMES intervention mainly consisted of amino acid derivatives. These metabolites had strong correlations with protein intake and were associated with preserved muscle volume.
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Brum M, Nieberler M, Kehrwald C, Knopf K, Brunkhorst-Kanaan N, Etyemez S, Allers KA, Bittner RA, Slattery DA, McNeill RV, Reif A, Kittel-Schneider S. Phase-and disorder-specific differences in peripheral metabolites of the kynurenine pathway in major depression, bipolar affective disorder and schizophrenia. World J Biol Psychiatry 2023; 24:564-577. [PMID: 36648064 DOI: 10.1080/15622975.2023.2169348] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023]
Abstract
OBJECTIVES Kynurenine, kynurenic and quinolinic acid are important metabolites in tryptophan metabolism. Due to an involvement in glutamatergic neurotransmission and immune response, previous studies have investigated this pathway in mental disorders such as major depressive disorder (MDD), bipolar disorder (BD) or schizophrenia (SCZ). Tryptophan and kynurenine have been shown to be decreased across disorders, hinting at the missing link how inflammation causes neurotoxicity and psychiatric symptoms. The main aim of our study was to investigate if individual catabolites could serve as diagnostic biomarkers for MDD, BD and SCZ. METHODS We measured plasma levels of tryptophan, kynurenine, kynurenic acid, quinolinic acid and ratio of quinolinic acid/kynurenic acid using mass spectrometry in n = 175 participants with acute episodes and after remission, compared with controls. RESULTS Decreased levels of all tryptophan catabolites were found in the whole patient group, driven by the difference between BD and HC. Manic and mixed phase BD individuals displayed significantly lower kynurenine and kynurenic acid levels. We could not find significant differences between disorders. Upon reaching remission, changes in catabolite levels partially normalised. CONCLUSIONS Our data suggests an involvement of the kynurenine pathway in mental disorders, especially BD but disqualifying those metabolites as biomarkers for differential diagnosis.
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Affiliation(s)
- Murielle Brum
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
| | - Matthias Nieberler
- Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital, University of Wuerzburg, Wuerzburg, Germany
| | - Christopher Kehrwald
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
| | - Katrin Knopf
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
| | - Nathalie Brunkhorst-Kanaan
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
| | - Semra Etyemez
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
- Current: Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kelly A Allers
- CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Robert A Bittner
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
- Ernst Struengmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt, Germany
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
| | - Rhiannon V McNeill
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
- Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital, University of Wuerzburg, Wuerzburg, Germany
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
| | - Sarah Kittel-Schneider
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University of Frankfurt, Frankfurt, Germany
- Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital, University of Wuerzburg, Wuerzburg, Germany
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Cremone IM, Nardi B, Amatori G, Palego L, Baroni D, Casagrande D, Massimetti E, Betti L, Giannaccini G, Dell'Osso L, Carpita B. Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions. Biomedicines 2023; 11:1600. [PMID: 37371695 DOI: 10.3390/biomedicines11061600] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/27/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.
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Affiliation(s)
- Ivan Mirko Cremone
- Department of Clinical and Experimental Medicine, University of Pisa, via Roma 67, 56126 Pisa, Italy
| | - Benedetta Nardi
- Department of Clinical and Experimental Medicine, University of Pisa, via Roma 67, 56126 Pisa, Italy
| | - Giulia Amatori
- Department of Clinical and Experimental Medicine, University of Pisa, via Roma 67, 56126 Pisa, Italy
| | - Lionella Palego
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Dario Baroni
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Danila Casagrande
- Department of Clinical and Experimental Medicine, University of Pisa, via Roma 67, 56126 Pisa, Italy
| | - Enrico Massimetti
- ASST Bergamo Ovest, SSD Psychiatric Diagnosis and Treatment Service, 24047 Treviglio, Italy
| | - Laura Betti
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | | | - Liliana Dell'Osso
- Department of Clinical and Experimental Medicine, University of Pisa, via Roma 67, 56126 Pisa, Italy
| | - Barbara Carpita
- Department of Clinical and Experimental Medicine, University of Pisa, via Roma 67, 56126 Pisa, Italy
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Yang C, Liao C, Zhao J, Guan Q, Wang G, Han Q. Dysregulation of tryptophan metabolism and distortion of cell signaling after oral exposure to ethanol and Kynurenic acid. Gene 2023; 852:147061. [PMID: 36423775 DOI: 10.1016/j.gene.2022.147061] [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: 08/29/2022] [Revised: 10/28/2022] [Accepted: 11/16/2022] [Indexed: 11/23/2022]
Abstract
Kynurenic acid (KYNA), an unavoidable tryptophan metabolite during fermentation is naturally blended with alcohol in all alcoholic beverages. Thus, alcohol drinking inevitably results in co-intake of KYNA. Effects of alcohol or KYNA on human health have been widely studied. However, the combined effects of both remain unknown. Here we report that alcohol and KYNA have a synergistic impact of on global gene expression, especially the gene sets related to tryptophan metabolism and cell signaling. Adult mice were exposed to alcohol (ethanol) and/or KYNA daily for a week. Transcriptomes of the brain, kidney and liver were profiled via bulk RNA sequencing. Results indicate that while KYNA alone largely promotes, and alcohol alone mostly inhibits gene expression, alcohol and KYNA co-administration has a stronger inhibition of global gene expression. Tryptophan metabolism is severely skewed towards kynurenine pathway by decreasing tryptophan hydroxylase 2 and increasing tryptophan dioxygenase. Quantification of tryptophan metabolic enzymes corroborates the transcriptional changes of these enzymes. Furthermore, the co-administration greatly enhances the GnRH signaling pathway. This research provides critical data to better understand the effects of alcohol and KYNA in mix on human health.
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Affiliation(s)
- Cihan Yang
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan 570228, China.
| | - Chenghong Liao
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan 570228, China; One Health Institute, Hainan University, Haikou, Hainan 570228, China.
| | - Jianguo Zhao
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan 570228, China; One Health Institute, Hainan University, Haikou, Hainan 570228, China.
| | - Qingfeng Guan
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan 570228, China; One Health Institute, Hainan University, Haikou, Hainan 570228, China.
| | - Guoshun Wang
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
| | - Qian Han
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan 570228, China; One Health Institute, Hainan University, Haikou, Hainan 570228, China.
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9
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Kynurenine Pathway in Diabetes Mellitus-Novel Pharmacological Target? Cells 2023; 12:cells12030460. [PMID: 36766803 PMCID: PMC9913876 DOI: 10.3390/cells12030460] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
The tryptophan-kynurenine pathway (Trp-KYN) is the major route for tryptophan conversion in the brain and in the periphery. Kynurenines display a wide range of biological actions (which are often contrasting) such as cytotoxic/cytoprotective, oxidant/antioxidant or pro-/anti-inflammatory. The net effect depends on their local concentration, cellular environment, as well as a complex positive and negative feedback loops. The imbalance between beneficial and harmful kynurenines was implicated in the pathogenesis of various neurodegenerative disorders, psychiatric illnesses and metabolic disorders, including diabetes mellitus (DM). Despite available therapies, DM may lead to serious macro- and microvascular complications including cardio- and cerebrovascular disease, peripheral vascular disease, chronic renal disease, diabetic retinopathy, autonomic neuropathy or cognitive impairment. It is well established that low-grade inflammation, which often coincides with DM, can affect the function of KP and, conversely, that kynurenines may modulate the immune response. This review provides a detailed summary of findings concerning the status of the Trp-KYN pathway in DM based on available animal, human and microbiome studies. We highlight the importance of the molecular interplay between the deranged (functionally and qualitatively) conversion of Trp to kynurenines in the development of DM and insulin resistance. The Trp-KYN pathway emerges as a novel target in the search for preventive and therapeutic interventions in DM.
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Yilmaz NS, Sen B, Karadag RF, Aslan S, Ekmekci Ertek I, Bozkurt A, Cicek S, Bolu A, Ucar H, Kocak C, Cevik C, Bukan N. A kynurenine pathway enzyme aminocarboxymuconate-semialdehyde decarboxylase may be involved in treatment-resistant depression, and baseline inflammation status of patients predicts treatment response: a pilot study. J Neural Transm (Vienna) 2022; 129:1513-1526. [PMID: 36334154 DOI: 10.1007/s00702-022-02553-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/16/2022] [Indexed: 11/07/2022]
Abstract
The kynurenine pathway (KP) and inflammation are substantial in depression pathogenesis. Although there is a crosstalk between the KP, inflammation, and neurotrophic factors, few studies examine these topics together. Novel medications may be developed by clarifying dysregulations related to inflammation, KP, and neurotrophic factors in treatment-resistant depression (TRD). We aimed to evaluate the serum levels of KP metabolites, proinflammatory biomarkers, and brain-derived neurotrophic factor (BDNF) in healthy controls (HC) and the patients with TRD whose followed up with three different treatments. Moreover, the effect of electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS) on biomarkers was investigated. Study groups comprised a total of 30 unipolar TRD patients consisting of three separate patient groups (ECT = 8, rTMS = 10, pharmacotherapy = 12), and 9 HC. The decision to administer only pharmacotherapy or ECT/rTMS besides pharmacotherapy was given independently of this research by psychiatrists. Blood samples and symptom scores were obtained three times for patients. At baseline, quinolinic acid (QUIN) was higher in the patients with TRD compared to HC, whereas picolinic acid (PIC), PIC/QUIN, and PIC/3-hydroxykynurenine were lower. Baseline interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hsCRP) were higher in nonresponders and non-remitters. ECT had an acute effect on cytokines. In the rTMS group, tumor necrosis factor-α (TNF-α) decreased in time. PIC, QUIN, and aminocarboxymuconate-semialdehyde decarboxylase (ACMSD) enzyme may play a role in TRD pathogenesis, and have diagnostic potential. rTMS and ECT have modulatory effects on low-grade inflammation seen in TRD. Baseline inflammation severity is predictive in terms of response and remission in depression.
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Affiliation(s)
- Niyazi Samet Yilmaz
- Department of Medical Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey.
| | - Bayram Sen
- Department of Medical Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | | | - Selcuk Aslan
- Department of Psychiatry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Irem Ekmekci Ertek
- Department of Psychiatry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Aruz Bozkurt
- Department of Psychiatry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Saba Cicek
- Department of Psychiatry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Abdullah Bolu
- Department of Psychiatry, Health Sciences University Gulhane Training and Research Hospital, Ankara, Turkey
| | - Huseyin Ucar
- Department of Psychiatry, Health Sciences University Gulhane Training and Research Hospital, Ankara, Turkey
| | - Cemal Kocak
- Republic of Turkey Ministry of Health, General Directorate of Public Health, Ankara, Turkey
| | - Cemal Cevik
- Department of Medical Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Neslihan Bukan
- Department of Medical Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey
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11
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A Review of the Health Benefits of Food Enriched with Kynurenic Acid. Nutrients 2022; 14:nu14194182. [PMID: 36235834 PMCID: PMC9570704 DOI: 10.3390/nu14194182] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/02/2022] [Accepted: 10/04/2022] [Indexed: 11/17/2022] Open
Abstract
Kynurenic acid (KYNA), a metabolite of tryptophan, is an endogenous substance produced intracellularly by various human cells. In addition, KYNA can be synthesized by the gut microbiome and delivered in food. However, its content in food is very low and the total alimentary supply with food accounts for only 1-3% of daily KYNA excretion. The only known exception is chestnut honey, which has a higher KYNA content than other foods by at least two orders of magnitude. KYNA is readily absorbed from the gastrointestinal tract; it is not metabolized and is excreted mainly in urine. It possesses well-defined molecular targets, which allows the study and elucidation of KYNA's role in various pathological conditions. Following a period of fascination with KYNA's importance for the central nervous system, research into its role in the peripheral system has been expanding rapidly in recent years, bringing some exciting discoveries. KYNA does not penetrate from the peripheral circulation into the brain; hence, the following review summarizes knowledge on the peripheral consequences of KYNA administration, presents data on KYNA content in food products, in the context of its daily supply in diets, and systematizes the available pharmacokinetic data. Finally, it provides an analysis of the rationale behind enriching foods with KYNA for health-promoting effects.
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12
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Tanaka M, Szabó Á, Spekker E, Polyák H, Tóth F, Vécsei L. Mitochondrial Impairment: A Common Motif in Neuropsychiatric Presentation? The Link to the Tryptophan-Kynurenine Metabolic System. Cells 2022; 11:cells11162607. [PMID: 36010683 PMCID: PMC9406499 DOI: 10.3390/cells11162607] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/14/2022] [Accepted: 08/19/2022] [Indexed: 02/07/2023] Open
Abstract
Nearly half a century has passed since the discovery of cytoplasmic inheritance of human chloramphenicol resistance. The inheritance was then revealed to take place maternally by mitochondrial DNA (mtDNA). Later, a number of mutations in mtDNA were identified as a cause of severe inheritable metabolic diseases with neurological manifestation, and the impairment of mitochondrial functions has been probed in the pathogenesis of a wide range of illnesses including neurodegenerative diseases. Recently, a growing number of preclinical studies have revealed that animal behaviors are influenced by the impairment of mitochondrial functions and possibly by the loss of mitochondrial stress resilience. Indeed, as high as 54% of patients with one of the most common primary mitochondrial diseases, mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, present psychiatric symptoms including cognitive impairment, mood disorder, anxiety, and psychosis. Mitochondria are multifunctional organelles which produce cellular energy and play a major role in other cellular functions including homeostasis, cellular signaling, and gene expression, among others. Mitochondrial functions are observed to be compromised and to become less resilient under continuous stress. Meanwhile, stress and inflammation have been linked to the activation of the tryptophan (Trp)-kynurenine (KYN) metabolic system, which observably contributes to the development of pathological conditions including neurological and psychiatric disorders. This review discusses the functions of mitochondria and the Trp-KYN system, the interaction of the Trp-KYN system with mitochondria, and the current understanding of the involvement of mitochondria and the Trp-KYN system in preclinical and clinical studies of major neurological and psychiatric diseases.
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Affiliation(s)
- Masaru Tanaka
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - Ágnes Szabó
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Doctoral School of Clinical Medicine, University of Szeged, Korányi fasor 6, H-6720 Szeged, Hungary
| | - Eleonóra Spekker
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - Helga Polyák
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Doctoral School of Clinical Medicine, University of Szeged, Korányi fasor 6, H-6720 Szeged, Hungary
| | - Fanni Tóth
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - László Vécsei
- ELKH-SZTE Neuroscience Research Group, Danube Neuroscience Research Laboratory, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-545-351
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13
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The Role of Tryptophan Dysmetabolism and Quinolinic Acid in Depressive and Neurodegenerative Diseases. Biomolecules 2022; 12:biom12070998. [PMID: 35883554 PMCID: PMC9313172 DOI: 10.3390/biom12070998] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/04/2022] [Accepted: 07/14/2022] [Indexed: 02/04/2023] Open
Abstract
Emerging evidence suggests that neuroinflammation is involved in both depression and neurodegenerative diseases. The kynurenine pathway, generating metabolites which may play a role in pathogenesis, is one of several competing pathways of tryptophan metabolism. The present article is a narrative review of tryptophan metabolism, neuroinflammation, depression, and neurodegeneration. A disturbed tryptophan metabolism with increased activity of the kynurenine pathway and production of quinolinic acid may result in deficiencies in tryptophan and derived neurotransmitters. Quinolinic acid is an N-methyl-D-aspartate receptor agonist, and raised levels in CSF, together with increased levels of inflammatory cytokines, have been reported in mood disorders. Increased quinolinic acid has also been observed in neurodegenerative diseases, including Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, and HIV-related cognitive decline. Oxidative stress in connection with increased indole-dioxygenase (IDO) activity and kynurenine formation may contribute to inflammatory responses and the production of cytokines. Increased formation of quinolinic acid may occur at the expense of kynurenic acid and neuroprotective picolinic acid. While awaiting ongoing research on potential pharmacological interventions on tryptophan metabolism, adequate protein intake with appropriate amounts of tryptophan and antioxidants may offer protection against oxidative stress and provide a balanced set of physiological receptor ligands.
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14
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Tanaka M, Spekker E, Szabó Á, Polyák H, Vécsei L. Modelling the neurodevelopmental pathogenesis in neuropsychiatric disorders. Bioactive kynurenines and their analogues as neuroprotective agents-in celebration of 80th birthday of Professor Peter Riederer. J Neural Transm (Vienna) 2022; 129:627-642. [PMID: 35624406 DOI: 10.1007/s00702-022-02513-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/05/2022] [Indexed: 02/06/2023]
Abstract
Following introduction of the monoamine oxidase type B inhibitor selegiline for the treatment of Parkinson's disease (PD), discovery of the action mechanism of Alzheimer's disease-modifying agent memantine, the role of iron in PD, and the loss of electron transport chain complex I in PD, and development of the concept of clinical neuroprotection, Peter Riederer launched one of the most challenging research project neurodevelopmental aspects of neuropsychiatric disorders. The neurodevelopmental theory holds that a disruption of normal brain development in utero or during early life underlies the subsequent emergence of neuropsychiatric symptoms during later life. Indeed, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Classification of Diseases, 11th Revision categorize autism spectrum disorder and attention deficit hyperactivity disorder in neurodevelopmental disorders (NDDs). More and more evidence, especially from preclinical studies, is revealing that neurodevelopmental pathology is not limited to the diagnostic class above, but also contributes to the development of other psychiatric disorders such as schizophrenia, bipolar disorder, and obsessive-compulsive disorder as well as neurodegenerative diseases such as PD and Huntington's disease. Preclinical animal research is taking a lead in understanding the pathomechanisms of NDDs, searching for novel targets, and developing new neuroprotective agents against NDDs. This narrative review discusses emerging evidence of the neurodevelopmental etiology of neuropsychiatric disorders, recent advances in modelling neurodevelopmental pathogenesis, potential strategies of clinical neuroprotection using novel kynurenine metabolites and analogues, and future research direction for NDDs.
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Affiliation(s)
- Masaru Tanaka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, 6725, Szeged, Hungary
| | - Eleonóra Spekker
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, 6725, Szeged, Hungary
| | - Ágnes Szabó
- Department of Neurology, Albert Szent-György Medical School, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - Helga Polyák
- Department of Neurology, Albert Szent-György Medical School, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - László Vécsei
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, 6725, Szeged, Hungary. .,Department of Neurology, Albert Szent-György Medical School, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary.
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15
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Martos D, Tuka B, Tanaka M, Vécsei L, Telegdy G. Memory Enhancement with Kynurenic Acid and Its Mechanisms in Neurotransmission. Biomedicines 2022; 10:biomedicines10040849. [PMID: 35453599 PMCID: PMC9027307 DOI: 10.3390/biomedicines10040849] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 03/28/2022] [Accepted: 04/02/2022] [Indexed: 02/04/2023] Open
Abstract
Kynurenic acid (KYNA) is an endogenous tryptophan (Trp) metabolite known to possess neuroprotective property. KYNA plays critical roles in nociception, neurodegeneration, and neuroinflammation. A lower level of KYNA is observed in patients with neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases or psychiatric disorders such as depression and autism spectrum disorders, whereas a higher level of KYNA is associated with the pathogenesis of schizophrenia. Little is known about the optimal concentration for neuroprotection and the threshold for neurotoxicity. In this study the effects of KYNA on memory functions were investigated by passive avoidance test in mice. Six different doses of KYNA were administered intracerebroventricularly to previously trained CFLP mice and they were observed for 24 h. High doses of KYNA (i.e., 20–40 μg/2 μL) significantly decreased the avoidance latency, whereas a low dose of KYNA (0.5 μg/2 μL) significantly elevated it compared with controls, suggesting that the low dose of KYNA enhanced memory function. Furthermore, six different receptor blockers were applied to reveal the mechanisms underlying the memory enhancement induced by KYNA. The series of tests revealed the possible involvement of the serotonergic, dopaminergic, α and β adrenergic, and opiate systems in the nootropic effect. This study confirmed that a low dose of KYNA improved a memory component of cognitive domain, which was mediated by, at least in part, four systems of neurotransmission in an animal model of learning and memory.
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Affiliation(s)
- Diána Martos
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - Bernadett Tuka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - Masaru Tanaka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - László Vécsei
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-342-361
| | - Gyula Telegdy
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 5, H-6725 Szeged, Hungary;
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16
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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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