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Bhadhprasit W, Kinoshita C, Matsumura N, Aoyama K. Erythroid Differentiation Regulator 1 as a Regulator of Neuronal GSH Synthesis. Antioxidants (Basel) 2024; 13:771. [PMID: 39061840 PMCID: PMC11274251 DOI: 10.3390/antiox13070771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 06/14/2024] [Accepted: 06/22/2024] [Indexed: 07/28/2024] Open
Abstract
Erythroid differentiation regulator 1 (Erdr1) is a cytokine known to play important roles in cell survival under stressful conditions, maintenance of cellular growth homeostasis, and activation of the immune system. However, the impact of Erdr1 on neurons remains undefined. In this study, we present novel evidence that Erdr1 plays a role in regulating glutathione (GSH) synthesis via glutamate transporter-associated protein 3-18 (GTRAP3-18), an anchor protein in the endoplasmic reticulum that holds excitatory amino acid carrier 1 (EAAC1) in neurons. Both DNA microarray and quantitative real-time PCR analyses revealed an approximately 2-fold increase in Erdr1 levels in the hippocampus of GTRAP3-18-deficient mice compared to those of wild-type mice. Knockdown of Erdr1 in vitro resulted in a decrease in GTRAP3-18 levels, leading to an increase in EAAC1 expression and intracellular GSH levels, and subsequently, cytoprotective effects against oxidative stress. Our findings shed light on the regulatory mechanisms involving Erdr1, GTRAP3-18, EAAC1, and GSH in the context of neuronal defense against oxidative stress. Understanding the intricate interplay among these molecules may pave the way for the development of promising therapeutic strategies for neurodegenerative disorders.
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Affiliation(s)
| | | | | | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo 173-8605, Japan; (W.B.); (C.K.); (N.M.)
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2
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Erdos T, Masuda M, Venketaraman V. Glutathione in HIV-Associated Neurocognitive Disorders. Curr Issues Mol Biol 2024; 46:5530-5549. [PMID: 38921002 PMCID: PMC11202908 DOI: 10.3390/cimb46060330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/27/2024] Open
Abstract
A large portion of patients with Human Immunodeficiency Virus (HIV) have neurologic sequelae. Those with better-controlled HIV via antiretroviral therapies generally have less severe neurologic symptoms. However, for many patients, antiretrovirals do not adequately resolve symptoms. Since much of the pathogenesis of HIV/AIDS (Autoimmune Deficiency Syndrome) involves oxidative stress either directly, through viral interaction, or indirectly, through inflammatory mechanisms, we have reviewed relevant trials of glutathione supplementation in each of the HIV-associated neurocognitive diseases and have found disease-specific results. For diseases for which trials have not been completed, predicted responses to glutathione supplementation are made based on relevant mechanisms seen in the literature. It is not sufficient to conclude that all HIV-associated neurocognitive disorders (HAND) will benefit from the antioxidant effects of glutathione supplementation. The potential effects of glutathione supplementation in patients with HAND are likely to differ based on the specific HIV-associated neurocognitive disease.
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Affiliation(s)
| | | | - Vishwanath Venketaraman
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA; (T.E.); (M.M.)
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3
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Xu X, Wang SS, Zhang L, Lu AX, Lin Y, Liu JX, Yan CH. Methylmercury induced ferroptosis by interference of iron homeostasis and glutathione metabolism in CTX cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 335:122278. [PMID: 37517642 DOI: 10.1016/j.envpol.2023.122278] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 07/20/2023] [Accepted: 07/26/2023] [Indexed: 08/01/2023]
Abstract
Environmental methylmercury (MeHg) exposure has gained global attention owing to its serious health hazards, especially neurotoxicity. Ferroptosis is a novel form of programmed cell death characterized by lipid peroxidation and iron overload. However, the occurrence of ferroptosis and its underlying mechanisms have not been fully elucidated in the methylmercury-induced neurotoxicity and the role of Nrf2 in MeHg-induced ferroptosis remains unexplored. In this study, we verified that MeHg decreased cell viability in a dose- and time-dependent manner in the Rat Brain Astrocytes cells (CTX cells). MeHg (3.5 μmol/L) exposure induced CTX cells to undergo ferroptosis, as evidenced by glutathione (GSH) depletion, lipid peroxidation, and iron overload, which was significantly rescued by the ferroptosis-specific inhibitors Ferrostatin-1 and Deferoxamine. MeHg directly disrupted the process of GSH metabolism by downregulating of SLC7A11 and GPX4 and interfered with intracellular iron homeostasis through inhibition of iron storage and export. Simultaneously, the expression of Nrf2 was upregulated by MeHg in CTX cells. Hence, the inhibition of Nrf2 activity further downregulated the levels of GPX4, SLC7A11, FTH1, and SLC40A1, which aggravated MeHg-induced ferroptosis to a greater extent. Overall, our findings provided evidence that ferroptosis played a critical role in MeHg-induced neurotoxicity, and suppressing Nrf2 activity further exacerbated MeHg-induced ferroptosis in CTX cells.
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Affiliation(s)
- Xi Xu
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Su-Su Wang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lin Zhang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - An-Xin Lu
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yin Lin
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun-Xia Liu
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chong-Huai Yan
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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The Protective Role of Glutathione on Zinc-Induced Neuron Death after Brain Injuries. Int J Mol Sci 2023; 24:ijms24032950. [PMID: 36769273 PMCID: PMC9917832 DOI: 10.3390/ijms24032950] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023] Open
Abstract
Glutathione (GSH) is necessary for maintaining physiological antioxidant function, which is responsible for maintaining free radicals derived from reactive oxygen species at low levels and is associated with improved cognitive performance after brain injury. GSH is produced by the linkage of tripeptides that consist of glutamic acid, cysteine, and glycine. The adequate supplementation of GSH has neuroprotective effects in several brain injuries such as cerebral ischemia, hypoglycemia, and traumatic brain injury. Brain injuries produce an excess of reactive oxygen species through complex biochemical cascades, which exacerbates primary neuronal damage. GSH concentrations are known to be closely correlated with the activities of certain genes such as excitatory amino acid carrier 1 (EAAC1), glutamate transporter-associated protein 3-18 (Gtrap3-18), and zinc transporter 3 (ZnT3). Following brain-injury-induced oxidative stress, EAAC1 function is negatively impacted, which then reduces cysteine absorption and impairs neuronal GSH synthesis. In these circumstances, vesicular zinc is also released into the synaptic cleft and then translocated into postsynaptic neurons. The excessive influx of zinc inhibits glutathione reductase, which inhibits GSH's antioxidant functions in neurons, resulting in neuronal damage and ultimately in the impairment of cognitive function. Therefore, in this review, we explore the overall relationship between zinc and GSH in terms of oxidative stress and neuronal cell death. Furthermore, we seek to understand how the modulation of zinc can rescue brain-insult-induced neuronal death after ischemia, hypoglycemia, and traumatic brain injury.
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Omata D, Munakata L, Maruyama K, Suzuki R. Enhanced Vascular Permeability by Microbubbles and Ultrasound in Drug Delivery. Biol Pharm Bull 2021; 44:1391-1398. [PMID: 34602547 DOI: 10.1248/bpb.b21-00453] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ultrasound and microbubbles, an ultrasound contrast agent, have recently increased attention to developing novel drug delivery systems. Ultrasound exposure can induce mechanical effects derived from microbubbles behaviors such as an expansion, contraction, and collapse depending on ultrasound conditions. These mechanical effects induce several biological effects, including enhancement of vascular permeability. For drug delivery, one promising approach is enhancing vascular permeability using ultrasound and microbubbles, resulting in improved drug transport to targeted tissues. This approach is applied to several tissues and drugs to cure diseases. This review describes the enhancement of vascular permeability by ultrasound and microbubbles and its therapeutic application, including our recent study. We also discuss the current situation of the field and its potential future perspectives.
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Affiliation(s)
- Daiki Omata
- Laboratory of Drug and Gene Delivery Research, Faculty of Pharma-Science, Teikyo University
| | - Lisa Munakata
- Laboratory of Drug and Gene Delivery Research, Faculty of Pharma-Science, Teikyo University
| | - Kazuo Maruyama
- Laboratory of Theranostics, Faculty of Pharma-Science, Teikyo University.,Advanced Comprehensive Research Organization (ACRO), Teikyo University
| | - Ryo Suzuki
- Laboratory of Drug and Gene Delivery Research, Faculty of Pharma-Science, Teikyo University.,Advanced Comprehensive Research Organization (ACRO), Teikyo University
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6
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Zhu M, Jia L, Jia J. Inhibition of miR-96-5p May Reduce Aβ42/Aβ40 Ratio via Regulating ATP-binding cassette transporter A1. J Alzheimers Dis 2021; 83:367-377. [PMID: 34334400 DOI: 10.3233/jad-210411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Imbalance between amyloid-β (Aβ) production and clearance results in Aβ accumulation. Regulating Aβ levels is still a hot point in the research of Alzheimer's disease (AD). OBJECTIVE To identify the differential expression of ATP-binding cassette transporter A1 (ABCA1) and its upstream microRNA (miRNA) in AD models, and to explore their relationships with Aβ levels. METHODS Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were performed to determine the expression of ABCA1 in 5xFAD mice, SH-SY5Y cells treated with Aβ oligomers and SH-SY5YAβPP695 cells (AD models). TargetScan was used to predict the upstream miRNAs for ABCA1. Dual-luciferase assay was conducted to identify the regulation of the miRNA on ABCA1. qRT-PCR was used to measure the expression of miRNA in AD models. Finally, enzyme-linked immunosorbent assays were performed to detect Aβ42 and Aβ40 levels. RESULTS The expression of ABCA1 was significantly downregulated in AD models at both mRNA and protein levels. Dual-luciferase assay showed that miR-96-5p could regulate the expression of ABCA1 through binding to the 3 untranslated region of ABCA1. The level of miR-96-5p was significantly elevated in AD models. The expression of ABCA1 was enhanced while Aβ42 levels and Aβ42/Aβ40 ratios were reduced in SH-SY5YAβPP695 cells after treated with miR-96-5p inhibitor. CONCLUSION The current study found that miR-96-5p is the upstream miRNA for ABCA1. Suppression of miR-96-5p in AD models could reduce Aβ42/Aβ40 ratios via upregulating the expression of ABCA1, indicating that miR-96-5p plays an important role in regulating the content of Aβ.
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Affiliation(s)
- Min Zhu
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, P.R. China
| | - Longfei Jia
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, P.R. China
| | - Jianping Jia
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Clinical Center for Neurodegenerative Disease and Memory Impairment, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, P.R. China.,Key Laboratory of Neurodegenerative Diseases, Ministry of Education, Beijing, P.R. China
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7
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Kinoshita C, Kubota N, Aoyama K. Interplay of RNA-Binding Proteins and microRNAs in Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22105292. [PMID: 34069857 PMCID: PMC8157344 DOI: 10.3390/ijms22105292] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/14/2021] [Accepted: 05/15/2021] [Indexed: 02/07/2023] Open
Abstract
The number of patients with neurodegenerative diseases (NDs) is increasing, along with the growing number of older adults. This escalation threatens to create a medical and social crisis. NDs include a large spectrum of heterogeneous and multifactorial pathologies, such as amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and multiple system atrophy, and the formation of inclusion bodies resulting from protein misfolding and aggregation is a hallmark of these disorders. The proteinaceous components of the pathological inclusions include several RNA-binding proteins (RBPs), which play important roles in splicing, stability, transcription and translation. In addition, RBPs were shown to play a critical role in regulating miRNA biogenesis and metabolism. The dysfunction of both RBPs and miRNAs is often observed in several NDs. Thus, the data about the interplay among RBPs and miRNAs and their cooperation in brain functions would be important to know for better understanding NDs and the development of effective therapeutics. In this review, we focused on the connection between miRNAs, RBPs and neurodegenerative diseases.
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Affiliation(s)
- Chisato Kinoshita
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan;
- Correspondence: (C.K.); (K.A.); Tel.: +81-3-3964-3794 (C.K.); +81-3-3964-3793 (K.A.)
| | - Noriko Kubota
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan;
- Teikyo University Support Center for Women Physicians and Researchers, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan;
- Correspondence: (C.K.); (K.A.); Tel.: +81-3-3964-3794 (C.K.); +81-3-3964-3793 (K.A.)
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8
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Abstract
Glutathione (GSH) is the most abundant non-protein thiol, and plays crucial roles in the antioxidant defense system and the maintenance of redox homeostasis in neurons. GSH depletion in the brain is a common finding in patients with neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease, and can cause neurodegeneration prior to disease onset. Excitatory amino acid carrier 1 (EAAC1), a sodium-dependent glutamate/cysteine transporter that is selectively present in neurons, plays a central role in the regulation of neuronal GSH production. The expression of EAAC1 is posttranslationally controlled by the glutamate transporter-associated protein 3–18 (GTRAP3-18) or miR-96-5p in neurons. The regulatory mechanism of neuronal GSH production mediated by EAAC1 may be a new target in therapeutic strategies for these neurodegenerative diseases. This review describes the regulatory mechanism of neuronal GSH production and its potential therapeutic application in the treatment of neurodegenerative diseases.
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9
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Kinoshita C, Kikuchi-Utsumi K, Aoyama K, Suzuki R, Okamoto Y, Matsumura N, Omata D, Maruyama K, Nakaki T. Inhibition of miR-96-5p in the mouse brain increases glutathione levels by altering NOVA1 expression. Commun Biol 2021; 4:182. [PMID: 33568779 PMCID: PMC7876013 DOI: 10.1038/s42003-021-01706-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Glutathione (GSH) is an important antioxidant that plays a critical role in neuroprotection. GSH depletion in neurons induces oxidative stress and thereby promotes neuronal damage, which in turn is regarded as a hallmark of the early stage of neurodegenerative diseases. The neuronal GSH level is mainly regulated by cysteine transporter EAAC1 and its inhibitor, GTRAP3-18. In this study, we found that the GTRAP3-18 level was increased by up-regulation of the microRNA miR-96-5p, which was found to decrease EAAC1 levels in our previous study. Since the 3'-UTR region of GTRAP3-18 lacks the consensus sequence for miR-96-5p, an unidentified protein should be responsible for the intermediate regulation of GTRAP3-18 expression by miR-96-5p. Here, we discovered that RNA-binding protein NOVA1 functions as an intermediate protein for GTRAP3-18 expression via miR-96-5p. Moreover, we show that intra-arterial injection of a miR-96-5p-inhibiting nucleic acid to living mice by a drug delivery system using microbubbles and ultrasound decreased the level of GTRAP3-18 via NOVA1 and increased the levels of EAAC1 and GSH in the dentate gyrus of the hippocampus. These findings suggest that the delivery of a miR-96-5p inhibitor to the brain would efficiently increase the neuroprotective activity by increasing GSH levels via EAAC1, GTRAP3-18 and NOVA1.
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Affiliation(s)
- Chisato Kinoshita
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | | | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | - Ryo Suzuki
- Laboratory of Drug and Gene Delivery, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Yayoi Okamoto
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
- Teikyo University Support Center for Women Physicians and Researchers, Tokyo, Japan
| | - Nobuko Matsumura
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | - Daiki Omata
- Laboratory of Drug and Gene Delivery, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Kazuo Maruyama
- Laboratory of Theranostics, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Toshio Nakaki
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan.
- Faculty of Pharma-Science, Teikyo University, Tokyo, Japan.
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10
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Matsumura N, Kinoshita C, Aoyama K. [Mechanism of glutathione production in neurons]. Nihon Yakurigaku Zasshi 2021; 156:26-30. [PMID: 33390476 DOI: 10.1254/fpj.20068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Glutathione (GSH) is a tripeptide consisting of glutamate, cysteine, and glycine that acts as an important neuroprotective molecule in the central nervous system. In neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, GSH levels in the brain would be decreased before the onset, and GSH dysregulation is considered to be involved in the development of these neurodegenerative diseases. Cysteine uptake into neurons is the rate-limiting step for GSH synthesis. Excitatory amino acid carrier 1 (EAAC1), which is a glutamate/cysteine cotransporter, is responsible for the neuronal cysteine uptake, and EAAC1 dysfunction reduces GSH levels in the brain and has a significant influence on the process of neurodegeneration. Since miR-96-5p, which is one of microRNAs, suppresses EAAC1 expression, it is conceivable that miR-96-5p inhibitor suppresses the onset or slows the progression of neurodegenerative diseases by increasing EAAC1 levels leading to promoting neuronal GSH production.
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Affiliation(s)
- Nobuko Matsumura
- Department of Pharmacology, Teikyo University School of Medicine
| | | | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine
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Malar DS, Prasanth MI, Brimson JM, Sharika R, Sivamaruthi BS, Chaiyasut C, Tencomnao T. Neuroprotective Properties of Green Tea ( Camellia sinensis) in Parkinson's Disease: A Review. Molecules 2020; 25:E3926. [PMID: 32867388 PMCID: PMC7504552 DOI: 10.3390/molecules25173926] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/14/2020] [Accepted: 08/14/2020] [Indexed: 12/21/2022] Open
Abstract
Neurodegenerative disease is a collective term given for the clinical condition, which results in progressive degeneration of neurons and the loss of functions associated with the affected brain region. Apart from the increase in age, neurodegenerative diseases are also partly affected by diet and lifestyle practices. Parkinson's disease (PD) is a slow onset neurodegenerative disorder and the second most common neurodegenerative disease, which affects the motor system. Although there is no prescribed treatment method to prevent and cure PD, clinical procedures help manage the disease symptoms. Green tea polyphenols are known for several health benefits, including antioxidant, anti-inflammatory, and neuroprotective activity. The current manuscript summarizes the possible mechanisms of neuroprotective potential of green tea with a special focus on PD. Studies have suggested that the consumption of green tea protects against free-radicals, inflammation, and neuro-damages. Several in vivo studies aid in understanding the overall mechanism of green tea. However, the same dose may not be sufficient in humans to elicit similar effects due to complex physiological, social, and cultural development. Future research focused on more clinical trials could identify an optimum dose that could impart maximum health benefits to impart neuroprotection in PD.
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Affiliation(s)
- Dicson Sheeja Malar
- Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand; (D.S.M.); (M.I.P.); (J.M.B.)
| | - Mani Iyer Prasanth
- Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand; (D.S.M.); (M.I.P.); (J.M.B.)
| | - James Michael Brimson
- Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand; (D.S.M.); (M.I.P.); (J.M.B.)
| | - Rajasekharan Sharika
- 309, Vrinda, 10th Cross, Railway Layout, Vijayanagar 2nd Stage, Mysuru, Karnataka 570016, India;
| | - Bhagavathi Sundaram Sivamaruthi
- Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand; (B.S.S.); (C.C.)
| | - Chaiyavat Chaiyasut
- Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand; (B.S.S.); (C.C.)
| | - Tewin Tencomnao
- Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand; (D.S.M.); (M.I.P.); (J.M.B.)
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12
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Shi C, Wang P, Airen S, Brown C, Liu Z, Townsend JH, Wang J, Jiang H. Nutritional and medical food therapies for diabetic retinopathy. EYE AND VISION (LONDON, ENGLAND) 2020; 7:33. [PMID: 32582807 PMCID: PMC7310218 DOI: 10.1186/s40662-020-00199-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 05/28/2020] [Indexed: 02/07/2023]
Abstract
Diabetic retinopathy (DR) is a form of microangiopathy. Reducing oxidative stress in the mitochondria and cell membranes decreases ischemic injury and end-organ damage to the retina. New approaches are needed, which reduce the risk and improve the outcomes of DR while complementing current therapeutic approaches. Homocysteine (Hcy) elevation and oxidative stress are potential therapeutic targets in DR. Common genetic polymorphisms such as those of methylenetetrahydrofolate reductase (MTHFR), increase Hcy and DR risk and severity. Patients with DR have high incidences of deficiencies of crucial vitamins, minerals, and related compounds, which also lead to elevation of Hcy and oxidative stress. Addressing the effects of the MTHFR polymorphism and addressing comorbid deficiencies and insufficiencies reduce the impact and severity of the disease. This approach provides safe and simple strategies that support conventional care and improve outcomes. Suboptimal vitamin co-factor availability also impairs the release of neurotrophic and neuroprotective growth factors. Collectively, this accounts for variability in presentation and response of DR to conventional therapy. Fortunately, there are straightforward recommendations for addressing these issues and supporting traditional treatment plans. We have reviewed the literature for nutritional interventions that support conventional therapies to reduce disease risk and severity. Optimal combinations of vitamins B1, B2, B6, L-methylfolate, methylcobalamin (B12), C, D, natural vitamin E complex, lutein, zeaxanthin, alpha-lipoic acid, and n-acetylcysteine are identified for protecting the retina and choroid. Certain medical foods have been successfully used as therapy for retinopathy. Recommendations based on this review and our clinical experience are developed for clinicians to use to support conventional therapy for DR. DR from both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) have similar retinal findings and responses to nutritional therapies.
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Affiliation(s)
- Ce Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Peng Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Shriya Airen
- College of Arts and Sciences, University of Miami, Miami, FL USA
| | - Craig Brown
- Department of Ophthalmology, College of Medicine, the University of Arkansas for Medical Sciences, Fayetteville, AR USA
| | - Zhiping Liu
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
- Ophthalmic Center, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong China
| | - Justin H. Townsend
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
| | - Hong Jiang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL USA
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13
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Escobar AP, Wendland JR, Chávez AE, Moya PR. The Neuronal Glutamate Transporter EAAT3 in Obsessive-Compulsive Disorder. Front Pharmacol 2019; 10:1362. [PMID: 31803055 PMCID: PMC6872633 DOI: 10.3389/fphar.2019.01362] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/28/2019] [Indexed: 01/03/2023] Open
Abstract
Obsessive compulsive disorder (OCD) is a heterogeneous psychiatric disorder affecting 1%–3% of the population worldwide. About half of OCD afflicted individuals do not respond to currently available pharmacotherapy, which is mainly based on serotonin reuptake inhibition. Therefore, there is a critical need to search novel and improved therapeutic targets to treat this devastating disorder. In recent years, accumulating evidence has supported the glutamatergic hypothesis of OCD, and particularly pointing a potential role for the neuronal glutamate transporter EAAT3. This mini-review summarizes recent findings regarding the neurobiological basis of OCD, with an emphasis on the glutamatergic neurotransmission and EAAT3 as a key player in OCD etiology.
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Affiliation(s)
- Angélica P Escobar
- Centro Interdisciplinario de Neurociencia de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Jens R Wendland
- Centro Interdisciplinario de Neurociencia de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Andrés E Chávez
- Centro Interdisciplinario de Neurociencia de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Pablo R Moya
- Centro Interdisciplinario de Neurociencia de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
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14
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Nakhate KT, Bharne AP, Verma VS, Aru DN, Kokare DM. Plumbagin ameliorates memory dysfunction in streptozotocin induced Alzheimer’s disease via activation of Nrf2/ARE pathway and inhibition of β-secretase. Biomed Pharmacother 2018; 101:379-390. [DOI: 10.1016/j.biopha.2018.02.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/31/2018] [Accepted: 02/13/2018] [Indexed: 01/01/2023] Open
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15
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Kinoshita C, Aoyama K, Nakaki T. Neuroprotection afforded by circadian regulation of intracellular glutathione levels: A key role for miRNAs. Free Radic Biol Med 2018; 119:17-33. [PMID: 29198727 DOI: 10.1016/j.freeradbiomed.2017.11.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 01/17/2023]
Abstract
Circadian rhythms are approximately 24-h oscillations of physiological and behavioral processes that allow us to adapt to daily environmental cycles. Like many other biological functions, cellular redox status and antioxidative defense systems display circadian rhythmicity. In the central nervous system (CNS), glutathione (GSH) is a critical antioxidant because the CNS is extremely vulnerable to oxidative stress; oxidative stress, in turn, causes several fatal diseases, including neurodegenerative diseases. It has long been known that GSH level shows circadian rhythm, although the mechanism underlying GSH rhythm production has not been well-studied. Several lines of recent evidence indicate that the expression of antioxidant genes involved in GSH homeostasis as well as circadian clock genes are regulated by post-transcriptional regulator microRNA (miRNA), indicating that miRNA plays a key role in generating GSH rhythm. Interestingly, several reports have shown that alterations of miRNA expression as well as circadian rhythm have been known to link with various diseases related to oxidative stress. A growing body of evidence implicates a strong correlation between antioxidative defense, circadian rhythm and miRNA function, therefore, their dysfunctions could cause numerous diseases. It is hoped that continued elucidation of the antioxidative defense systems controlled by novel miRNA regulation under circadian control will advance the development of therapeutics for the diseases caused by oxidative stress.
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Affiliation(s)
- Chisato Kinoshita
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Toshio Nakaki
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
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16
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Aoyama K, Bhadhprasit W, Watabe M, Wang F, Matsumura N, Nakaki T. GTRAP3-18 regulates food intake and body weight by interacting with pro-opiomelanocortin. FASEB J 2017; 32:330-341. [PMID: 28904020 DOI: 10.1096/fj.201700421r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/28/2017] [Indexed: 01/16/2023]
Abstract
Pro-opiomelanocortin (POMC)-expressing neurons provide α-melanocyte-stimulating hormone (α-MSH), which stimulates melanocortin 4 receptor to induce hypophagia by AMPK inhibition in the hypothalamus. α-MSH is produced by POMC cleavage in secretory granules and released. However, it is not known yet whether any posttranscriptional regulatory mechanism of POMC signaling exists upstream of the secretory granules in neurons. Here we show that glutamate transporter-associated protein 3-18 (GTRAP3-18), an anchor protein that retains interacting proteins in the endoplasmic reticulum, is a critical regulator of food intake and body weight by interacting with POMC. GTRAP3-18-deficient mice showed hypophagia, lean bodies, and lower blood glucose, insulin, and leptin levels with increased serum and brain α-MSH levels, leading to AMPK inhibition. Intraperitoneal glucose tolerance tests revealed significantly decreased blood glucose levels and areas under the curve in GTRAP3-18-deficient mice compared to wild-type mice. An intracerebroventricular infusion of a selective melanocortin 4 receptor antagonist to GTRAP3-18-deficient mice significantly increased their food intake and body weight. A fluorescence resonance energy transfer study showed an interaction between GTRAP3-18 and POMC in vitro These findings suggest that activation of the melanocortin pathway by modulating GTRAP3-18/POMC interaction could be an alternative strategy for obesity and/or type 2 diabetes.-Aoyama, K., Bhadhprasit, W., Watabe, M., Wang, F., Matsumura, N., Nakaki, T. GTRAP3-18 regulates food intake and body weight by interacting with pro-opiomelanocortin.
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Affiliation(s)
- Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | | | - Masahiko Watabe
- General Medical Education Center (G-MEC), Teikyo University School of Medicine, Tokyo, Japan
| | - Fan Wang
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | - Nobuko Matsumura
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | - Toshio Nakaki
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan;
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17
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Afshari P, Yao WD, Middleton FA. Reduced Slc1a1 expression is associated with neuroinflammation and impaired sensorimotor gating and cognitive performance in mice: Implications for schizophrenia. PLoS One 2017; 12:e0183854. [PMID: 28886095 PMCID: PMC5590851 DOI: 10.1371/journal.pone.0183854] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 08/11/2017] [Indexed: 12/11/2022] Open
Abstract
We previously reported a 84-Kb hemi-deletion copy number variant at the SLC1A1 gene locus that reduces its expression and appeared causally linked to schizophrenia. In this report, we characterize the in vivo and in vitro consequences of reduced expression of Slc1a1 in mice. Heterozygous (HET) Slc1a1+/- mice, which more closely model the hemi-deletion we found in human subjects, were examined in a series of behavioral, anatomical and biochemical assays. Knockout (KO) mice were also included in the behavioral studies for comparative purposes. Both HET and KO mice exhibited evidence of increased anxiety-like behavior, impaired working memory, decreased exploratory activity and impaired sensorimotor gating, but no changes in overall locomotor activity. The magnitude of changes was approximately equivalent in the HET and KO mice suggesting a dominant effect of the haploinsufficiency. Behavioral changes in the HET mice were accompanied by reduced thickness of the dorsomedial prefrontal cortex. Whole transcriptome RNA-Seq analysis detected expression changes of genes and pathways involved in cytokine signaling and synaptic functions in both brain and blood. Moreover, the brains of Slc1a1+/- mice displayed elevated levels of oxidized glutathione, a trend for increased oxidative DNA damage, and significantly increased levels of cytokines. This latter finding was further supported by SLC1A1 knockdown and overexpression studies in differentiated human neuroblastoma cells, which led to decreased or increased cytokine expression, respectively. Taken together, our results suggest that partial loss of the Slc1a1 gene in mice causes haploinsufficiency associated with behavioral, histological and biochemical changes that reflect an altered redox state and may promote the expression of behavioral features and inflammatory states consistent with those observed in schizophrenia.
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Affiliation(s)
- Parisa Afshari
- Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY United States of America
| | - Wei-Dong Yao
- Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY United States of America.,Department of Psychiatry & Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America
| | - Frank A Middleton
- Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY United States of America.,Department of Psychiatry & Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America.,Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States of America
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18
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Bjørn-Yoshimoto WE, Underhill SM. The importance of the excitatory amino acid transporter 3 (EAAT3). Neurochem Int 2016; 98:4-18. [PMID: 27233497 DOI: 10.1016/j.neuint.2016.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 05/09/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022]
Abstract
The neuronal excitatory amino acid transporter 3 (EAAT3) is fairly ubiquitously expressed in the brain, though it does not necessarily maintain the same function everywhere. It is important in maintaining low local concentrations of glutamate, where its predominant post-synaptic localization can buffer nearby glutamate receptors and modulate excitatory neurotransmission and synaptic plasticity. It is also the main neuronal cysteine uptake system acting as the rate-limiting factor for the synthesis of glutathione, a potent antioxidant, in EAAT3 expressing neurons, while on GABAergic neurons, it is important in supplying glutamate as a precursor for GABA synthesis. Several diseases implicate EAAT3, and modulation of this transporter could prove a useful therapeutic approach. Regulation of EAAT3 could be targeted at several points for functional modulation, including the level of transcription, trafficking and direct pharmacological modulation, and indeed, compounds and experimental treatments have been identified that regulate EAAT3 function at different stages, which together with observations of EAAT3 regulation in patients is giving us insight into the endogenous function of this transporter, as well as the consequences of altered function. This review summarizes work done on elucidating the role and regulation of EAAT3.
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Affiliation(s)
- Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
| | - Suzanne M Underhill
- National Institute of Mental Health, National Institutes of Health, 35 Convent Drive Room 3A: 210 MSC3742, Bethesda, MD 20892-3742, USA.
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Aoyama K, Nakaki T. Glutathione in Cellular Redox Homeostasis: Association with the Excitatory Amino Acid Carrier 1 (EAAC1). Molecules 2015; 20:8742-58. [PMID: 26007177 PMCID: PMC6272787 DOI: 10.3390/molecules20058742] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 05/11/2015] [Indexed: 12/15/2022] Open
Abstract
Reactive oxygen species (ROS) are by-products of the cellular metabolism of oxygen consumption, produced mainly in the mitochondria. ROS are known to be highly reactive ions or free radicals containing oxygen that impair redox homeostasis and cellular functions, leading to cell death. Under physiological conditions, a variety of antioxidant systems scavenge ROS to maintain the intracellular redox homeostasis and normal cellular functions. This review focuses on the antioxidant system’s roles in maintaining redox homeostasis. Especially, glutathione (GSH) is the most important thiol-containing molecule, as it functions as a redox buffer, antioxidant, and enzyme cofactor against oxidative stress. In the brain, dysfunction of GSH synthesis leading to GSH depletion exacerbates oxidative stress, which is linked to a pathogenesis of aging-related neurodegenerative diseases. Excitatory amino acid carrier 1 (EAAC1) plays a pivotal role in neuronal GSH synthesis. The regulatory mechanism of EAAC1 is also discussed.
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Affiliation(s)
| | - Toshio Nakaki
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-3-3964-3793; Fax: +81-3-3964-0602
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Sha S, Xu J, Lu ZH, Hong J, Qu WJ, Zhou JW, Chen L. Lack of JWA Enhances Neurogenesis and Long-Term Potentiation in Hippocampal Dentate Gyrus Leading to Spatial Cognitive Potentiation. Mol Neurobiol 2014; 53:355-368. [PMID: 25432888 DOI: 10.1007/s12035-014-9010-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 11/14/2014] [Indexed: 01/28/2023]
Abstract
JWA (Arl6ip5), a homologous gene of glutamate-transporter-associated protein 3-18 (GTRAP3-18) and addicsin, is highly expressed in hippocampus. We generated systemic and neuronal JWA knockout (JWA-KO and JWA-nKO) mice to investigate the influence of JWA deficiency on spatial cognitive performance, process of neurogenesis, and induction of long-term potentiation (LTP) in hippocampal dentate gyrus (DG). In comparison with wild-type (WT) mice and JWA (loxP/loxP) (control of JWA-nKO) mice, 8-week-old JWA-KO mice and JWA-nKO mice showed spatial cognitive potentiation as assessed by Morris water maze test. In hippocampal DG of JWA-nKO mice, either survival and migration or neurite growth of newborn neurons were significantly enhanced without the changes in proliferation and differentiation of stem cells. In addition, the increase of LTP amplitude and the decline of LTP threshold were observed in DG, but not in CA1 region, of JWA-nKO mice compared to control mice. The levels of hippocampal FAK, Akt, and mTOR phosphorylation in JWA-nKO mice were higher than those in control mice. The PI3K or FAK inhibitor could abolish the enhanced neurogenesis and LTP induction in JWA-nKO mice, which was accompanied by disappearance of the spatial cognitive potentiation. The treatment of JWA-nKO mice with 3'-azido-3'-deoxythymidine (AZT), a telomerase inhibitor, suppressed not only the enhanced neurogenesis but also the enhanced LTP induction in DG, but it did not affect the LTP induction in CA1 region. The results suggest that the JWA deficiency through cascading FAK-PI3K-Akt-mTOR pathway increases the newborn neurons and enhances the LTP induction in hippocampal DG, which leads to the spatial cognitive potentiation.
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Affiliation(s)
- Sha Sha
- Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, 210029, China
- Department of Physiology, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China
| | - Jin Xu
- Department of Molecular Cell Biology and Toxicology, School of Public Health, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China
| | - Zi-Hong Lu
- Department of Physiology, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China
| | - Juan Hong
- Department of Physiology, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China
| | - Wei-Jun Qu
- Department of Physiology, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China
| | - Jian-Wei Zhou
- Department of Molecular Cell Biology and Toxicology, School of Public Health, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China.
| | - Ling Chen
- Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
- Department of Physiology, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu, 210029, China.
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21
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Power EM, Empson RM. Functional contributions of glutamate transporters at the parallel fibre to Purkinje neuron synapse-relevance for the progression of cerebellar ataxia. CEREBELLUM & ATAXIAS 2014; 1:3. [PMID: 26331027 PMCID: PMC4549135 DOI: 10.1186/2053-8871-1-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 03/19/2014] [Indexed: 01/09/2023]
Abstract
Background Rapid uptake of glutamate by neuronal and glial glutamate transporters (EAATs, a family of excitatory amino acid transporters) is critical for shaping synaptic responses and for preventing excitotoxicity. Two of these transporters, EAAT4 in Purkinje neurons (PN) and EAAT1 in Bergmann glia are both enriched within the cerebellum and altered in a variety of human ataxias. Results PN excitatory synaptic responses and firing behaviour following high frequency parallel fibre (PF) activity commonly encountered during sensory stimulation in vivo were adversely influenced by acute inhibition of glutamate transporters. In the presence of a non-transportable blocker of glutamate transporters we observed very large amplitude and duration excitatory postsynaptic currents accompanied by excessive firing of the PNs. A combination of AMPA and mGluR1, but not NMDA, type glutamate receptor activation powered the hyper-excitable PN state. The enhanced PN excitability also recruited a presynaptic mGluR4 dependent mechanism that modified short term plasticity at the PF synapse. Conclusions Our findings indicate that reduced glutamate transporter activity, as occurs in the early stages of some forms of human cerebellar ataxias, excessively excites PNs and disrupts the timing of their output. Our findings raise the possibility that sustaining cerebellar glutamate uptake may provide a therapeutic approach to prevent this disruption and the glutamate excitotoxicity-induced PN death that signals the end point of the disease.
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Affiliation(s)
- Emmet M Power
- Department of Physiology, Brain Health Research Centre, University of Otago School of Medical Sciences, PO Box 56, 9054 Dunedin, New Zealand
| | - Ruth M Empson
- Department of Physiology, Brain Health Research Centre, University of Otago School of Medical Sciences, PO Box 56, 9054 Dunedin, New Zealand
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Bianchi MG, Bardelli D, Chiu M, Bussolati O. Changes in the expression of the glutamate transporter EAAT3/EAAC1 in health and disease. Cell Mol Life Sci 2014; 71:2001-15. [PMID: 24162932 PMCID: PMC11113519 DOI: 10.1007/s00018-013-1484-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 12/14/2022]
Abstract
Excitatory amino acid transporters (EAATs) are high-affinity Na(+)-dependent carriers of major importance in maintaining glutamate homeostasis in the central nervous system. EAAT3, the human counterpart of the rodent excitatory amino acid carrier 1 (EAAC1), is encoded by the SLC1A1 gene. EAAT3/EAAC1 is ubiquitously expressed in the brain, mostly in neurons but also in other cell types, such as oligodendrocyte precursors. While most of the glutamate released in the synapses is taken up by the "glial-type" EAATs, EAAT2 (GLT-1 in rodents) and EAAT1 (GLAST), the functional role of EAAT3/EAAC1 is related to the subtle regulation of glutamatergic transmission. Moreover, because it can also transport cysteine, EAAT3/EAAC1 is believed to be important for the synthesis of intracellular glutathione and subsequent protection from oxidative stress. In contrast to other EAATs, EAAT3/EAAC1 is mostly intracellular, and several mechanisms have been described for the rapid regulation of the membrane trafficking of the transporter. Moreover, the carrier interacts with several proteins, and this interaction modulates transport activity. Much less is known about the slow regulatory mechanisms acting on the expression of the transporter, although several recent reports have identified changes in EAAT3/EAAC1 protein level and activity related to modulation of its expression at the gene level. Moreover, EAAT3/EAAC1 expression is altered in pathological conditions, such as hypoxia/ischemia, multiple sclerosis, schizophrenia, and epilepsy. This review summarizes these results and provides an overall picture of changes in EAAT3/EAAC1 expression in health and disease.
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Affiliation(s)
- Massimiliano G. Bianchi
- Unit of General Pathology, Department of Biomedical, Biotechnological and Translational Sciences (SBiBiT), University of Parma, Via Volturno 39, 43125 Parma, Italy
- Unit of Occupational Medicine, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy
| | - Donatella Bardelli
- Unit of General Pathology, Department of Biomedical, Biotechnological and Translational Sciences (SBiBiT), University of Parma, Via Volturno 39, 43125 Parma, Italy
| | - Martina Chiu
- Unit of General Pathology, Department of Biomedical, Biotechnological and Translational Sciences (SBiBiT), University of Parma, Via Volturno 39, 43125 Parma, Italy
| | - Ovidio Bussolati
- Unit of General Pathology, Department of Biomedical, Biotechnological and Translational Sciences (SBiBiT), University of Parma, Via Volturno 39, 43125 Parma, Italy
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23
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Kinoshita C, Aoyama K, Matsumura N, Kikuchi-Utsumi K, Watabe M, Nakaki T. Rhythmic oscillations of the microRNA miR-96-5p play a neuroprotective role by indirectly regulating glutathione levels. Nat Commun 2014; 5:3823. [PMID: 24804999 PMCID: PMC4024755 DOI: 10.1038/ncomms4823] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 04/07/2014] [Indexed: 12/11/2022] Open
Abstract
Glutathione (GSH) is a key antioxidant that plays an important neuroprotective role in the brain. Decreased GSH levels are associated with neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease. Here we show that a diurnal fluctuation of GSH levels is correlated with neuroprotective activity against oxidative stress in dopaminergic cells. In addition, we found that the cysteine transporter excitatory amino acid carrier 1 (EAAC1), which is involved in neuronal GSH synthesis, is negatively regulated by the microRNA miR-96-5p, which exhibits a diurnal rhythm. Blocking miR-96-5p by intracerebroventricular administration of an inhibitor increased the level of EAAC1 as well as that of GSH and had a neuroprotective effect against oxidative stress in the mouse substantia nigra. Our results suggest that the diurnal rhythm of miR-96-5p may play a role in neuroprotection by regulating neuronal GSH levels via EAAC1. Glutathione is a key antioxidant that plays an important neuroprotective role in the brain. Here, Kinoshita et al. show that levels of glutathione exhibit diurnal fluctuations that are indirectly regulated by the microRNA miR-96-5p, and that this microRNA plays a neuroprotective role against oxidative stress.
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Affiliation(s)
- Chisato Kinoshita
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Nobuko Matsumura
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Kazue Kikuchi-Utsumi
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Masahiko Watabe
- 1] Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan [2] General Medical Education Center (G-MEC), Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Toshio Nakaki
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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Arano T, Fujisaki S, Ikemoto MJ. Identification of tomoregulin-1 as a novel addicsin-associated factor. Neurochem Int 2014; 71:22-35. [DOI: 10.1016/j.neuint.2014.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/14/2014] [Accepted: 03/18/2014] [Indexed: 11/28/2022]
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26
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Lane MC, Jackson JG, Krizman EN, Rothstein JD, Porter BE, Robinson MB. Genetic deletion of the neuronal glutamate transporter, EAAC1, results in decreased neuronal death after pilocarpine-induced status epilepticus. Neurochem Int 2013; 73:152-8. [PMID: 24334055 DOI: 10.1016/j.neuint.2013.11.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/26/2013] [Accepted: 11/28/2013] [Indexed: 11/24/2022]
Abstract
Excitatory amino acid carrier 1 (EAAC1 also called EAAT3) is a Na(+)-dependent glutamate transporter expressed by both glutamatergic and GABAergic neurons. It provides precursors for the syntheses of glutathione and GABA and contributes to the clearance of synaptically released glutamate. Mice deleted of EAAC1 are more susceptible to neurodegeneration in models of ischemia, Parkinson's disease, and aging. Antisense knock-down of EAAC1 causes an absence seizure-like phenotype. Additionally, EAAC1 expression increases after chemonvulsant-induced seizures in rodent models and in tissue specimens from patients with refractory epilepsy. The goal of the present study was to determine if the absence of EAAC1 affects the sensitivity of mice to seizure-induced cell death. A chemoconvulsant dose of pilocarpine was administered to EAAC1(-/-) mice and to wild-type controls. Although EAAC1(-/-) mice experienced increased latency to seizure onset, no significant differences in behavioral seizure severity or mortality were observed. We examined EAAC1 immunofluorescence 24h after pilocarpine administration and confirmed that pilocarpine causes an increase in EAAC1 protein. Forty-eight hours after induction of seizures, cell death was measured in hippocampus and in cortex using Fluoro-Jade C. Surprisingly, there was ∼2-fold more cell death in area CA1 of wild-type mice than in the corresponding regions of the EAAC1(-/-) mice. Together, these studies indicate that absence of EAAC1 results in either a decrease in pilocarpine-induced seizures that is not detectable by behavioral criteria (surprising, since EAAC1 provides glutamate for GABA synthesis), or that the absence of EAAC1 results in less pilocarpine/seizure-induced cell death, possible explanations as discussed.
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Affiliation(s)
- Meredith C Lane
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua G Jackson
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elizabeth N Krizman
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jeffery D Rothstein
- Department of Neurology and Neuroscience, Johns Hopkins University, Brain Sciences Institute, Baltimore, MD 21205, USA
| | - Brenda E Porter
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Neurology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael B Robinson
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pharmacology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA.
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27
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Aoyama K, Nakaki T. Impaired glutathione synthesis in neurodegeneration. Int J Mol Sci 2013; 14:21021-44. [PMID: 24145751 PMCID: PMC3821656 DOI: 10.3390/ijms141021021] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/30/2013] [Accepted: 10/01/2013] [Indexed: 12/20/2022] Open
Abstract
Glutathione (GSH) was discovered in yeast cells in 1888. Studies of GSH in mammalian cells before the 1980s focused exclusively on its function for the detoxication of xenobiotics or for drug metabolism in the liver, in which GSH is present at its highest concentration in the body. Increasing evidence has demonstrated other important roles of GSH in the brain, not only for the detoxication of xenobiotics but also for antioxidant defense and the regulation of intracellular redox homeostasis. GSH also regulates cell signaling, protein function, gene expression, and cell differentiation/proliferation in the brain. Clinically, inborn errors in GSH-related enzymes are very rare, but disorders of GSH metabolism are common in major neurodegenerative diseases showing GSH depletion and increased levels of oxidative stress in the brain. GSH depletion would precipitate oxidative damage in the brain, leading to neurodegenerative diseases. This review focuses on the significance of GSH function, the synthesis of GSH and its metabolism, and clinical disorders of GSH metabolism. A potential approach to increase brain GSH levels against neurodegeneration is also discussed.
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Affiliation(s)
- Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan.
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Neuroprotective properties of the excitatory amino acid carrier 1 (EAAC1). Amino Acids 2013; 45:133-42. [PMID: 23462929 DOI: 10.1007/s00726-013-1481-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/23/2013] [Indexed: 01/09/2023]
Abstract
Extracellular glutamate should be maintained at low levels to conserve optimal neurotransmission and prevent glutamate neurotoxicity in the brain. Excitatory amino acid transporters (EAATs) play a pivotal role in removing extracellular glutamate in the central nervous system (CNS). Excitatory amino acid carrier 1 (EAAC1) is a high-affinity Na⁺-dependent neuronal EAAT that is ubiquitously expressed in the brain. However, most glutamate released in the synapses is cleared by glial EAATs, but not by EAAC1 in vivo. In the CNS, EAAC1 is widely distributed in somata and dendrites but not in synaptic terminals. The contribution of EAAC1 to the control of extracellular glutamate levels seems to be negligible in the brain. However, EAAC1 can transport not only extracellular glutamate but also cysteine into the neurons. Cysteine is an important substrate for glutathione (GSH) synthesis in the brain. GSH has a variety of neuroprotective functions, while its depletion induces neurodegeneration. Therefore, EAAC1 might exert a critical role for neuroprotection in neuronal GSH metabolism rather than glutamatergic neurotransmission, while EAAC1 dysfunction would cause neurodegeneration. Despite the potential importance of EAAC1 in the brain, previous studies have mainly focused on the glutamate neurotoxicity induced by glial EAAT dysfunction. In recent years, however, several studies have revealed regulatory mechanisms of EAAC1 functions in the brain. This review will summarize the latest information on the EAAC1-regulated neuroprotective functions in the CNS.
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Effects of 18-kDa translocator protein knockdown on gene expression of glutamate receptors, transporters, and metabolism, and on cell viability affected by glutamate. Pharmacogenet Genomics 2012; 22:606-19. [PMID: 22732722 DOI: 10.1097/fpc.0b013e3283544531] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Previously, several important roles for glutamate have been described for the biology of primary brain tumors. For example, glutamate has been suggested to promote glioma cell proliferation by the activation of the 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid (AMPA) subtype of glutamate receptors. In the present study, we determined the potential regulatory roles of the 18-kDa translocator protein (TSPO) in the glutamatergic system in relation to cell death of brain tumor cells through knockdown of the TSPO by genetic manipulation. MATERIALS AND METHODS With microarray analysis and validation of gene expression of particular genes using real-time PCR, we found effects because of small inhibitory RNA knockdown of the TSPO in human U118MG glioblastoma cells on gene expression of glutamate receptors, glutamate transporters, and enzymes for glutamate metabolism. We also applied antisense RNA to silence TSPO in rat C6 glioblastoma cells and assayed the effects on DNA fragmentation, indicative of apoptosis, because of glutamate exposure. RESULTS In particular, the effects of TSPO silencing in human U118MG cells related to glutamate metabolism indicate a net effect of a reduction in glutamate levels, which may potentially protect the cells in question from cell death. The TSPO knockdown in C6 cells showed that TSPO is required for the induction of apoptosis because of glutamate exposure. CONCLUSION These findings show that interactions between the TSPO and the glutamatergic system may play a role in tumor development of glioblastoma cells. This may also have implications for our understanding of the involvement of the TSPO in secondary brain damage and neurodegenerative diseases.
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Aoyama K, Nakaki T. Inhibition of GTRAP3-18 may increase neuroprotective glutathione (GSH) synthesis. Int J Mol Sci 2012; 13:12017-12035. [PMID: 23109897 PMCID: PMC3472789 DOI: 10.3390/ijms130912017] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/06/2012] [Accepted: 09/10/2012] [Indexed: 01/24/2023] Open
Abstract
Glutathione (GSH) is a tripeptide consisting of glutamate, cysteine, and glycine; it has a variety of functions in the central nervous system. Brain GSH depletion is considered a preclinical sign in age-related neurodegenerative diseases, and it promotes the subsequent processes toward neurotoxicity. A neuroprotective mechanism accomplished by increasing GSH synthesis could be a promising approach in the treatment of neurodegenerative diseases. In neurons, cysteine is the rate-limiting substrate for GSH synthesis. Excitatory amino acid carrier 1 (EAAC1) is a neuronal cysteine/glutamate transporter in the brain. EAAC1 translocation to the plasma membrane promotes cysteine uptake, leading to GSH synthesis, while being negatively regulated by glutamate transport associated protein 3-18 (GTRAP3-18). Our recent studies have suggested GTRAP3-18 as an inhibitory factor for neuronal GSH synthesis. Inhibiting GTRAP3-18 function is an endogenous mechanism to increase neuron-specific GSH synthesis in the brain. This review gives an overview of EAAC1-mediated GSH synthesis, and its regulatory mechanisms by GTRAP3-18 in the brain, and a potential approach against neurodegeneration.
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Affiliation(s)
| | - Toshio Nakaki
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-3-3964-1211; Fax: +81-3-3964-0602
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The role of amino acid transporters in GSH synthesis in the blood-brain barrier and central nervous system. Neurochem Int 2012; 61:405-14. [PMID: 22634224 DOI: 10.1016/j.neuint.2012.05.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/17/2012] [Accepted: 05/15/2012] [Indexed: 12/22/2022]
Abstract
Glutathione (GSH) plays a critical role in protecting cells from oxidative stress and xenobiotics, as well as maintaining the thiol redox state, most notably in the central nervous system (CNS). GSH concentration and synthesis are highly regulated within the CNS and are limited by availability of the sulfhydryl amino acid (AA) l-cys, which is mainly transported from the blood, through the blood-brain barrier (BBB), and into neurons. Several antiporter transport systems (e.g., x(c)(-), x(-)(AG), and L) with clearly different luminal and abluminal distribution, Na(+), and pH dependency have been described in brain endothelial cells (BEC) of the BBB, as well as in neurons, astrocytes, microglia and oligodendrocytes from different brain structures. The purpose of this review is to summarize information regarding the different AA transport systems for l-cys and its oxidized form l-cys(2) in the CNS, such as expression and activity in blood-brain barrier endothelial cells, astrocytes and neurons and environmental factors that modulate transport kinetics.
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