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Miyamoto K, Sujino T, Kanai T. The tryptophan metabolic pathway of the microbiome and host cells in health and disease. Int Immunol 2024; 36:601-616. [PMID: 38869080 PMCID: PMC11562643 DOI: 10.1093/intimm/dxae035] [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: 02/22/2024] [Accepted: 06/06/2024] [Indexed: 06/14/2024] Open
Abstract
The intricate and dynamic tryptophan (Trp) metabolic pathway in both the microbiome and host cells highlights its profound implications for health and disease. This pathway involves complex interactions between host cellular and bacteria processes, producing bioactive compounds such as 5-hydroxytryptamine (5-HT) and kynurenine derivatives. Immune responses to Trp metabolites through specific receptors have been explored, highlighting the role of the aryl hydrocarbon receptor in inflammation modulation. Dysregulation of this pathway is implicated in various diseases, such as Alzheimer's and Parkinson's diseases, mood disorders, neuronal diseases, autoimmune diseases such as multiple sclerosis (MS), and cancer. In this article, we describe the impact of the 5-HT, Trp, indole, and Trp metabolites on health and disease. Furthermore, we review the impact of microbiome-derived Trp metabolites that affect immune responses and contribute to maintaining homeostasis, especially in an experimental autoimmune encephalitis model of MS.
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Affiliation(s)
- Kentaro Miyamoto
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
- Miyarisan Pharmaceutical Co., Research Laboratory, Tokyo, Japan
| | - Tomohisa Sujino
- Center for Diagnostic and Therapeutic Endoscopy, Keio University School of Medicine, Tokyo, Japan
- Keio Global Research Institute, Keio University, Tokyo, Japan
| | - Takanori Kanai
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
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Nicosia N, Giovenzana M, Misztak P, Mingardi J, Musazzi L. Glutamate-Mediated Excitotoxicity in the Pathogenesis and Treatment of Neurodevelopmental and Adult Mental Disorders. Int J Mol Sci 2024; 25:6521. [PMID: 38928227 PMCID: PMC11203689 DOI: 10.3390/ijms25126521] [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: 05/17/2024] [Revised: 06/09/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Glutamate is the main excitatory neurotransmitter in the brain wherein it controls cognitive functional domains and mood. Indeed, brain areas involved in memory formation and consolidation as well as in fear and emotional processing, such as the hippocampus, prefrontal cortex, and amygdala, are predominantly glutamatergic. To ensure the physiological activity of the brain, glutamatergic transmission is finely tuned at synaptic sites. Disruption of the mechanisms responsible for glutamate homeostasis may result in the accumulation of excessive glutamate levels, which in turn leads to increased calcium levels, mitochondrial abnormalities, oxidative stress, and eventually cell atrophy and death. This condition is known as glutamate-induced excitotoxicity and is considered as a pathogenic mechanism in several diseases of the central nervous system, including neurodevelopmental, substance abuse, and psychiatric disorders. On the other hand, these disorders share neuroplasticity impairments in glutamatergic brain areas, which are accompanied by structural remodeling of glutamatergic neurons. In the current narrative review, we will summarize the role of glutamate-induced excitotoxicity in both the pathophysiology and therapeutic interventions of neurodevelopmental and adult mental diseases with a focus on autism spectrum disorders, substance abuse, and psychiatric disorders. Indeed, glutamatergic drugs are under preclinical and clinical development for the treatment of different mental diseases that share glutamatergic neuroplasticity dysfunctions. Although clinical evidence is still limited and more studies are required, the regulation of glutamate homeostasis is attracting attention as a potential crucial target for the control of brain diseases.
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Affiliation(s)
- Noemi Nicosia
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (N.N.); (M.G.); (P.M.)
- PhD Program in Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Mattia Giovenzana
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (N.N.); (M.G.); (P.M.)
- PhD Program in Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Paulina Misztak
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (N.N.); (M.G.); (P.M.)
| | - Jessica Mingardi
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (N.N.); (M.G.); (P.M.)
| | - Laura Musazzi
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (N.N.); (M.G.); (P.M.)
- Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
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You Y, Chen Z, Hu WW. The role of microglia heterogeneity in synaptic plasticity and brain disorders: Will sequencing shed light on the discovery of new therapeutic targets? Pharmacol Ther 2024; 255:108606. [PMID: 38346477 DOI: 10.1016/j.pharmthera.2024.108606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/05/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Microglia play a crucial role in interacting with neuronal synapses and modulating synaptic plasticity. This function is particularly significant during postnatal development, as microglia are responsible for removing excessive synapses to prevent neurodevelopmental deficits. Dysregulation of microglial synaptic function has been well-documented in various pathological conditions, notably Alzheimer's disease and multiple sclerosis. The recent application of RNA sequencing has provided a powerful and unbiased means to decipher spatial and temporal microglial heterogeneity. By identifying microglia with varying gene expression profiles, researchers have defined multiple subgroups of microglia associated with specific pathological states, including disease-associated microglia, interferon-responsive microglia, proliferating microglia, and inflamed microglia in multiple sclerosis, among others. However, the functional roles of these distinct subgroups remain inadequately characterized. This review aims to refine our current understanding of the potential roles of heterogeneous microglia in regulating synaptic plasticity and their implications for various brain disorders, drawing from recent sequencing research and functional studies. This knowledge may aid in the identification of pathogenetic biomarkers and potential factors contributing to pathogenesis, shedding new light on the discovery of novel drug targets. The field of sequencing-based data mining is evolving toward a multi-omics approach. With advances in viral tools for precise microglial regulation and the development of brain organoid models, we are poised to elucidate the functional roles of microglial subgroups detected through sequencing analysis, ultimately identifying valuable therapeutic targets.
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Affiliation(s)
- Yi You
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhong Chen
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China; Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Wei-Wei Hu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China.
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Baek JH, Park H, Kang H, Kim R, Kang JS, Kim HJ. The Role of Glutamine Homeostasis in Emotional and Cognitive Functions. Int J Mol Sci 2024; 25:1302. [PMID: 38279303 PMCID: PMC10816396 DOI: 10.3390/ijms25021302] [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: 12/20/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/28/2024] Open
Abstract
Glutamine (Gln), a non-essential amino acid, is synthesized de novo by glutamine synthetase (GS) in various organs. In the brain, GS is exclusively expressed in astrocytes under normal physiological conditions, producing Gln that takes part in glutamatergic neurotransmission through the glutamate (Glu)-Gln cycle. Because the Glu-Gln cycle and glutamatergic neurotransmission play a pivotal role in normal brain activity, maintaining Gln homeostasis in the brain is crucial. Recent findings indicated that a neuronal Gln deficiency in the medial prefrontal cortex in rodents led to depressive behaviors and mild cognitive impairment along with lower glutamatergic neurotransmission. In addition, exogenous Gln supplementation has been tested for its ability to overcome neuronal Gln deficiency and reverse abnormal behaviors induced by chronic immobilization stress (CIS). Although evidence is accumulating as to how Gln supplementation contributes to normalizing glutamatergic neurotransmission and the Glu-Gln cycle, there are few reviews on this. In this review, we summarize recent evidence demonstrating that Gln supplementation ameliorates CIS-induced deleterious changes, including an imbalance of the Glu-Gln cycle, suggesting that Gln homeostasis is important for emotional and cognitive functions. This is the first review of detailed mechanistic studies on the effects of Gln supplementation on emotional and cognitive functions.
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Affiliation(s)
| | | | | | | | | | - Hyun Joon Kim
- Department of Anatomy and Convergence Medical Sciences, College of Medicine, Institute of Medical Science, Tyrosine Peptide Multiuse Research Group, Anti-Aging Bio Cell Factory Regional Leading Research Center, Gyeongsang National University, 15 Jinju-daero 816 Beongil, Jinju 52727, Gyeongnam, Republic of Korea; (J.H.B.); (H.P.); (H.K.); (R.K.); (J.S.K.)
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Asraf K, Zaidan H, Natoor B, Gaisler-Salomon I. Synergistic, long-term effects of glutamate dehydrogenase 1 deficiency and mild stress on cognitive function and mPFC gene and miRNA expression. Transl Psychiatry 2023; 13:248. [PMID: 37419882 DOI: 10.1038/s41398-023-02534-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 06/15/2023] [Accepted: 06/21/2023] [Indexed: 07/09/2023] Open
Abstract
Glutamate abnormalities in the medial prefrontal cortex (mPFC) are associated with cognitive deficits. We previously showed that homozygous deletion of CNS glutamate dehydrogenase 1 (Glud1), a metabolic enzyme critical for glutamate metabolism, leads to schizophrenia-like behavioral abnormalities and increased mPFC glutamate; mice heterozygous for CNS Glud1 deletion (C-Glud1+/- mice) showed no cognitive or molecular abnormalities. Here, we examined the protracted behavioral and molecular effects of mild injection stress on C-Glud1+/- mice. We found spatial and reversal learning deficits, as well as large-scale mPFC transcriptional changes in pathways associated with glutamate and GABA signaling, in stress-exposed C-Glud1+/- mice, but not in their stress-naïve or C-Glud1+/+ littermates. These effects were observed several weeks following stress exposure, and the expression levels of specific glutamatergic and GABAergic genes differentiated between high and low reversal learning performance. An increase in miR203-5p expression immediately following stress may provide a translational regulatory mechanism to account for the delayed effect of stress exposure on cognitive function. Our findings show that chronic glutamate abnormalities interact with acute stress to induce cognitive deficits, and resonate with gene x environment theories of schizophrenia. Stress-exposed C-Glud1+/- mice may model a schizophrenia high-risk population, which is uniquely sensitive to stress-related 'trigger' events.
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Affiliation(s)
- Kfir Asraf
- School of Psychological Sciences, Department of Psychology, University of Haifa, Haifa, 3498838, Israel
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, 3498838, Israel
| | - Hiba Zaidan
- School of Psychological Sciences, Department of Psychology, University of Haifa, Haifa, 3498838, Israel
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, 3498838, Israel
| | - Baylasan Natoor
- School of Psychological Sciences, Department of Psychology, University of Haifa, Haifa, 3498838, Israel
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, 3498838, Israel
| | - Inna Gaisler-Salomon
- School of Psychological Sciences, Department of Psychology, University of Haifa, Haifa, 3498838, Israel.
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa, 3498838, Israel.
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Yao J, Chen C, Guo Y, Yang Y, Liu X, Chu S, Ai Q, Zhang Z, Lin M, Yang S, Chen N. A Review of Research on the Association between Neuron-Astrocyte Signaling Processes and Depressive Symptoms. Int J Mol Sci 2023; 24:ijms24086985. [PMID: 37108148 PMCID: PMC10139177 DOI: 10.3390/ijms24086985] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/02/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Depression is a mental illness that has a serious negative impact on physical and mental health. The pathophysiology of depression is still unknown, and therapeutic medications have drawbacks, such as poor effectiveness, strong dependence, adverse drug withdrawal symptoms, and harmful side effects. Therefore, the primary purpose of contemporary research is to understand the exact pathophysiology of depression. The connection between astrocytes, neurons, and their interactions with depression has recently become the focus of great research interest. This review summarizes the pathological changes of neurons and astrocytes, and their interactions in depression, including the alterations of mid-spiny neurons and pyramidal neurons, the alterations of astrocyte-related biomarkers, and the alterations of gliotransmitters between astrocytes and neurons. In addition to providing the subjects of this research and suggestions for the pathogenesis and treatment techniques of depression, the intention of this article is to more clearly identify links between neuronal-astrocyte signaling processes and depressive symptoms.
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Affiliation(s)
- Jiao Yao
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
- Key Laboratory of Modern Research of TCM, Education Department of Hunan Province, Changsha 410208, China
| | - Cong Chen
- School of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha 410208, China
| | - Yi Guo
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
- School of Acupuncture & Tuina and Rehabilitation, Hunan University of Chinese Medicine, Changsha 410208, China
| | - Yantao Yang
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
| | - Xinya Liu
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
| | - Shifeng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Qidi Ai
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
- Key Laboratory of Modern Research of TCM, Education Department of Hunan Province, Changsha 410208, China
| | - Zhao Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Meiyu Lin
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
| | - Songwei Yang
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
- Key Laboratory of Modern Research of TCM, Education Department of Hunan Province, Changsha 410208, China
| | - Naihong Chen
- Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, College of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
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