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Koster KP, Fyke Z, Nguyen TTA, Niqula A, Noriega-González LY, Woolfrey KM, Dell’Acqua ML, Cologna SM, Yoshii A. Akap5 links synaptic dysfunction to neuroinflammatory signaling in a mouse model of infantile neuronal ceroid lipofuscinosis. Front Synaptic Neurosci 2024; 16:1384625. [PMID: 38798824 PMCID: PMC11116793 DOI: 10.3389/fnsyn.2024.1384625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/23/2024] [Indexed: 05/29/2024] Open
Abstract
Palmitoylation and depalmitoylation represent dichotomic processes by which a labile posttranslational lipid modification regulates protein trafficking and degradation. The depalmitoylating enzyme, palmitoyl-protein thioesterase 1 (PPT1), is associated with the devastating pediatric neurodegenerative condition, infantile neuronal ceroid lipofuscinosis (CLN1). CLN1 is characterized by the accumulation of autofluorescent lysosomal storage material (AFSM) in neurons and robust neuroinflammation. Converging lines of evidence suggest that in addition to cellular waste accumulation, the symptomology of CLN1 corresponds with disruption of synaptic processes. Indeed, loss of Ppt1 function in cortical neurons dysregulates the synaptic incorporation of the GluA1 AMPA receptor (AMPAR) subunit during a type of synaptic plasticity called synaptic scaling. However, the mechanisms causing this aberration are unknown. Here, we used the Ppt1-/- mouse model (both sexes) to further investigate how Ppt1 regulates synaptic plasticity and how its disruption affects downstream signaling pathways. To this end, we performed a palmitoyl-proteomic screen, which provoked the discovery that Akap5 is excessively palmitoylated at Ppt1-/- synapses. Extending our previous data, in vivo induction of synaptic scaling, which is regulated by Akap5, caused an excessive upregulation of GluA1 in Ppt1-/- mice. This synaptic change was associated with exacerbated disease pathology. Furthermore, the Akap5- and inflammation-associated transcriptional regulator, nuclear factor of activated T cells (NFAT), was sensitized in Ppt1-/- cortical neurons. Suppressing the upstream regulator of NFAT activation, calcineurin, with the FDA-approved therapeutic FK506 (Tacrolimus) modestly improved neuroinflammation in Ppt1-/- mice. These findings indicate that the absence of depalmitoylation stifles synaptic protein trafficking and contributes to neuroinflammation via an Akap5-associated mechanism.
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Affiliation(s)
- Kevin P. Koster
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Zach Fyke
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Thu T. A. Nguyen
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, United States
| | - Amanda Niqula
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | | | - Kevin M. Woolfrey
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Stephanie M. Cologna
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, United States
| | - Akira Yoshii
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL, United States
- Department of Neurology, University of Illinois at Chicago, Chicago, IL, United States
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Mackiewicz J, Tomczak J, Lisek M, Sakowicz A, Guo F, Boczek T. NFATc4 Knockout Promotes Neuroprotection and Retinal Ganglion Cell Regeneration After Optic Nerve Injury. Mol Neurobiol 2024:10.1007/s12035-024-04129-0. [PMID: 38639863 DOI: 10.1007/s12035-024-04129-0] [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: 12/27/2023] [Accepted: 03/19/2024] [Indexed: 04/20/2024]
Abstract
Retinal ganglion cells (RGCs), neurons transmitting visual information via the optic nerve, fail to regenerate their axons after injury. The progressive loss of RGC function underlies the pathophysiology of glaucoma and other optic neuropathies, often leading to irreversible blindness. Therefore, there is an urgent need to identify the regulators of RGC survival and the regenerative program. In this study, we investigated the role of the family of transcription factors known as nuclear factor of activated T cells (NFAT), which are expressed in the retina; however, their role in RGC survival after injury is unknown. Using the optic nerve crush (ONC) model, widely employed to study optic neuropathies and central nervous system axon injury, we found that NFATc4 is specifically but transiently up-regulated in response to mechanical injury. In the injured retina, NFATc4 immunolocalized primarily to the ganglionic cell layer. Utilizing NFATc4-/- and NFATc3-/- mice, we demonstrated that NFATc4, but not NFATc3, knockout increased RGC survival, improved retina function, and delayed axonal degeneration. Microarray screening data, along with decreased immunostaining of cleaved caspase-3, revealed that NFATc4 knockout was protective against ONC-induced degeneration by suppressing pro-apoptotic signaling. Finally, we used lentiviral-mediated NFATc4 delivery to the retina of NFATc4-/- mice and reversed the pro-survival effect of NFATc4 knockout, conclusively linking the enhanced survival of injured RGCs to NFATc4-dependent mechanisms. In summary, this study is the first to demonstrate that NFATc4 knockout may confer transient RGC neuroprotection and decelerate axonal degeneration after injury, providing a potent therapeutic strategy for optic neuropathies.
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Affiliation(s)
- Joanna Mackiewicz
- Department of Molecular Neurochemistry, Medical University of Lodz, Lodz, Poland
| | - Julia Tomczak
- Department of Molecular Neurochemistry, Medical University of Lodz, Lodz, Poland
| | - Malwina Lisek
- Department of Molecular Neurochemistry, Medical University of Lodz, Lodz, Poland
| | - Agata Sakowicz
- Department of Medical Biotechnology, Medical University of Lodz, Lodz, Poland
| | - Feng Guo
- Department of Pharmaceutical Toxicology, China Medical University, Shenyang, China.
| | - Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University of Lodz, Lodz, Poland.
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Mackiewicz J, Lisek M, Boczek T. Targeting CaN/NFAT in Alzheimer's brain degeneration. Front Immunol 2023; 14:1281882. [PMID: 38077352 PMCID: PMC10701682 DOI: 10.3389/fimmu.2023.1281882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/06/2023] [Indexed: 12/18/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive loss of cognitive functions. While the exact causes of this debilitating disorder remain elusive, numerous investigations have characterized its two core pathologies: the presence of β-amyloid plaques and tau tangles. Additionally, multiple studies of postmortem brain tissue, as well as results from AD preclinical models, have consistently demonstrated the presence of a sustained inflammatory response. As the persistent immune response is associated with neurodegeneration, it became clear that it may also exacerbate other AD pathologies, providing a link between the initial deposition of β-amyloid plaques and the later development of neurofibrillary tangles. Initially discovered in T cells, the nuclear factor of activated T-cells (NFAT) is one of the main transcription factors driving the expression of inflammatory genes and thus regulating immune responses. NFAT-dependent production of inflammatory mediators is controlled by Ca2+-dependent protein phosphatase calcineurin (CaN), which dephosphorylates NFAT and promotes its transcriptional activity. A substantial body of evidence has demonstrated that aberrant CaN/NFAT signaling is linked to several pathologies observed in AD, including neuronal apoptosis, synaptic deficits, and glia activation. In view of this, the role of NFAT isoforms in AD has been linked to disease progression at different stages, some of which are paralleled to diminished cognitive status. The use of classical inhibitors of CaN/NFAT signaling, such as tacrolimus or cyclosporine, or adeno-associated viruses to specifically inhibit astrocytic NFAT activation, has alleviated some symptoms of AD by diminishing β-amyloid neurotoxicity and neuroinflammation. In this article, we discuss the recent findings related to the contribution of CaN/NFAT signaling to the progression of AD and highlight the possible benefits of targeting this pathway in AD treatment.
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Affiliation(s)
| | | | - Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University of Lodz, Lodz, Poland
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Sant'Anna R, Robbs BK, de Freitas JA, Dos Santos PP, König A, Outeiro TF, Foguel D. The alpha-synuclein oligomers activate nuclear factor of activated T-cell (NFAT) modulating synaptic homeostasis and apoptosis. Mol Med 2023; 29:111. [PMID: 37596531 PMCID: PMC10439599 DOI: 10.1186/s10020-023-00704-8] [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: 03/31/2023] [Accepted: 07/18/2023] [Indexed: 08/20/2023] Open
Abstract
BACKGROUND Soluble oligomeric forms of alpha-synuclein (aSyn-O) are believed to be one of the main toxic species in Parkinson's disease (PD) leading to degeneration. aSyn-O can induce Ca2+ influx, over activating downstream pathways leading to PD phenotype. Calcineurin (CN), a phosphatase regulated by Ca2+ levels, activates NFAT transcription factors that are involved in the regulation of neuronal plasticity, growth, and survival. METHODS Here, using a combination of cell toxicity and gene regulation assays performed in the presence of classical inhibitors of the NFAT/CN pathway, we investigate NFAT's role in neuronal degeneration induced by aSyn-O. RESULTS aSyn-O are toxic to neurons leading to cell death, loss of neuron ramification and reduction of synaptic proteins which are reversed by CN inhibition with ciclosporin-A or VIVIT, a NFAT specific inhibitor. aSyn-O induce NFAT nuclear translocation and transactivation. We found that aSyn-O modulates the gene involved in the maintenance of synapses, synapsin 1 (Syn 1). Syn1 mRNA and protein and synaptic puncta are drastically reduced in cells treated with aSyn-O which are reversed by NFAT inhibition. CONCLUSIONS For the first time a direct role of NFAT in aSyn-O-induced toxicity and Syn1 gene regulation was demonstrated, enlarging our understanding of the pathways underpinnings synucleinopathies.
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Affiliation(s)
- Ricardo Sant'Anna
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Waldweg 33, 37073, Göttingen, Germany
- Centro de Ciências da Saúde, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Bloco E sala 42, Rio de Janeiro, 21941-590, Brazil
| | - Bruno K Robbs
- Departamento de Ciência Básica, Instituto de Saúde de Nova Friburgo, Universidade Federal Fluminense, Nova Friburgo, RJ, 28625-650, Brazil
| | - Júlia Araújo de Freitas
- Centro de Ciências da Saúde, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Bloco E sala 42, Rio de Janeiro, 21941-590, Brazil
| | - Patrícia Pires Dos Santos
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Annekatrin König
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Tiago Fleming Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, 37075, Göttingen, Germany.
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Göttingen, Germany.
| | - Debora Foguel
- Centro de Ciências da Saúde, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Bloco E sala 42, Rio de Janeiro, 21941-590, Brazil.
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Basu-Shrivastava M, Kozoriz A, Desagher S, Lassot I. To Ubiquitinate or Not to Ubiquitinate: TRIM17 in Cell Life and Death. Cells 2021; 10:1235. [PMID: 34069831 PMCID: PMC8157266 DOI: 10.3390/cells10051235] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/17/2022] Open
Abstract
TRIM17 is a member of the TRIM family, a large class of RING-containing E3 ubiquitin-ligases. It is expressed at low levels in adult tissues, except in testis and in some brain regions. However, it can be highly induced in stress conditions which makes it a putative stress sensor required for the triggering of key cellular responses. As most TRIM members, TRIM17 can act as an E3 ubiquitin-ligase and promote the degradation by the proteasome of substrates such as the antiapoptotic protein MCL1. Intriguingly, TRIM17 can also prevent the ubiquitination of other proteins and stabilize them, by binding to other TRIM proteins and inhibiting their E3 ubiquitin-ligase activity. This duality of action confers several pivotal roles to TRIM17 in crucial cellular processes such as apoptosis, autophagy or cell division, but also in pathological conditions as diverse as Parkinson's disease or cancer. Here, in addition to recent data that endorse this duality, we review what is currently known from public databases and the literature about TRIM17 gene regulation and expression, TRIM17 protein structure and interactions, as well as its involvement in cell physiology and human disorders.
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Affiliation(s)
| | - Alina Kozoriz
- Institut de Génétique Moléculaire de Montpellier, University Montpellier, CNRS, Montpellier, France
| | - Solange Desagher
- Institut de Génétique Moléculaire de Montpellier, University Montpellier, CNRS, Montpellier, France
| | - Iréna Lassot
- Institut de Génétique Moléculaire de Montpellier, University Montpellier, CNRS, Montpellier, France
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6
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Tsukahara C, Sase K, Fujita N, Takagi H, Kitaoka Y. Axonal Protection by Tacrolimus with Inhibition of NFATc1 in TNF-Induced Optic Nerve Degeneration. Neurochem Res 2019; 44:1726-1735. [PMID: 31087207 PMCID: PMC6555779 DOI: 10.1007/s11064-019-02804-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 11/25/2022]
Abstract
Tacrolimus, a calcineurin (CaN) inhibitor, has been used for treatment of refractory allergic ocular disease, although its role in optic nerve degeneration remains to be elucidated. In this study, we investigated whether tacrolimus modulates tumor necrosis factor (TNF)-mediated axonal degeneration and whether it alters nuclear factor of activated T cells (NFATc), a downstream effector of CaN signaling. Immunoblot analysis showed no significant difference in CaNAα protein levels in optic nerve on day 3, 7, or 14 after TNF injection compared with PBS injection. However, a significant increase in NFATc1 protein level was observed in optic nerve 7 days after TNF injection. This increase was negated by simultaneous administration of tacrolimus. Administration of tacrolimus alone did not change the NFATc1 protein level in comparison to that observed after PBS injection. A significant increase in TNF protein level was observed in optic nerve 14 days after TNF injection and this increase was prevented by tacrolimus. Immunohistochemical analysis showed the immunoreactivity of NFATc1 to be increased in optic nerve after TNF injection. This increased immunoreactivity was colocalized with glial fibrillary acidic protein and was suppressed by tacrolimus. Treatment of tacrolimus significantly ameliorated the TNF-mediated axonal loss. These results suggest that tacrolimus is neuroprotective against axon loss in TNF-induced optic neuropathy and that the effect arises from suppression of the CaN/NFATc1 pathway.
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Affiliation(s)
- Chihiro Tsukahara
- Department of Ophthalmology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, 216-8511, Kanagawa, Japan.
- Department of Molecular Neuroscience, St. Marianna University Graduate School of Medicine, Kawasaki, Japan.
| | - Kana Sase
- Department of Ophthalmology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, 216-8511, Kanagawa, Japan
| | - Naoki Fujita
- Department of Ophthalmology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, 216-8511, Kanagawa, Japan
- Department of Molecular Neuroscience, St. Marianna University Graduate School of Medicine, Kawasaki, Japan
| | - Hitoshi Takagi
- Department of Ophthalmology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, 216-8511, Kanagawa, Japan
| | - Yasushi Kitaoka
- Department of Ophthalmology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, 216-8511, Kanagawa, Japan
- Department of Molecular Neuroscience, St. Marianna University Graduate School of Medicine, Kawasaki, Japan
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7
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Tozaki-Saitoh H, Miyata H, Yamashita T, Matsushita K, Tsuda M, Inoue K. P2Y12 receptors in primary microglia activate nuclear factor of activated T-cell signaling to induce C-C chemokine 3 expression. J Neurochem 2017; 141:100-110. [PMID: 28144998 DOI: 10.1111/jnc.13968] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 02/03/2023]
Abstract
Microglia are widely accepted as surveillants in the central nervous system that are continually searching the local environment for signs of injury. Following an inflammatory situation, microglia alter their morphology, extend ramified processes, and undergo cell body hypertrophy. Extracellular nucleotides are recognized as a danger signal by microglia. ADP acting on P2Y12 receptors induce process extension of microglia thereby attracting microglia to the site of adenosine tri-phosphate/ADP leaking or release. However, the question whether ADP/P2Y12 receptor signaling directly stimulates the production or release of inducible factors such as cytokines remains unclear. In this study, we found that CC chemokine ligand 3 (CCL3) is induced by ADP-treated primary microglia. Pharmacological characterization using pertussis toxin, a P2Y12 receptor inhibitor, and a calcium chelator revealed that CCL3 induction was caused by P2Y12 receptor-mediated intracellular calcium elevation. Next, nuclear factor of activated T-cell dephosphorylation and nuclear translocalization were observed. Calcineurin, an inhibitor for nuclear factor of activated T cell, suppressed CCL3 induction. These data indicate that microglial P2Y12 receptors are utilized to trigger an acute inflammatory response in microglia via rapid CCL3 induction after ADP stimulation.
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Affiliation(s)
- Hidetoshi Tozaki-Saitoh
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Miyata
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomohiro Yamashita
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Katsuyuki Matsushita
- Department of Anesthesiology and Critical Care Medicine, Graduate School of Medical Sciences, Kyushu Universisty, Fukuoka, Japan
| | - Makoto Tsuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhide Inoue
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Manocha GD, Ghatak A, Puig KL, Kraner SD, Norris CM, Combs CK. NFATc2 Modulates Microglial Activation in the AβPP/PS1 Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2017; 58:775-787. [PMID: 28505967 PMCID: PMC6265241 DOI: 10.3233/jad-151203] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) brains are characterized by fibrillar amyloid-β (Aβ) peptide containing plaques and associated reactive microglia. The proinflammatory phenotype of the microglia suggests that they may negatively affect disease course and contribute to behavioral decline. This hypothesis predicts that attenuating microglial activation may provide benefit against disease. Prior work from our laboratory and others has characterized a role for the transcription factor, nuclear factor of activated T cells (NFAT), in regulating microglial phenotype in response to different stimuli, including Aβ peptide. We observed that the NFATc2 isoform was the most highly expressed in murine microglia cultures, and inhibition or deletion of NFATc2 was sufficient to attenuate the ability of the microglia to secrete cytokines. In order to determine whether the NFATc2 isoform, in particular, was a valid immunomodulatory target in vivo, we crossed an NFATc2-/- line to a well-known AD mouse model, an AβPP/PS1 mouse line. As expected, the AβPP/PS1 x NFATc2-/- mice had attenuated cytokine levels compared to AβPP/PS1 mice as well as reduced microgliosis and astrogliosis with no effect on plaque load. Although some species differences in relative isoform expression may exist between murine and human microglia, it appears that microglial NFAT activity is a viable target for modulating the proinflammatory changes that occur during AD.
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Affiliation(s)
- Gunjan D. Manocha
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Atreyi Ghatak
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Kendra L. Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Susan D. Kraner
- Department of Pharmacology and Nutritional Sciences and the Sanders Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Christopher M. Norris
- Department of Pharmacology and Nutritional Sciences and the Sanders Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Colin K. Combs
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
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Yao JJ, Zhao QR, Liu DD, Chow CW, Mei YA. Neuritin Up-regulates Kv4.2 α-Subunit of Potassium Channel Expression and Affects Neuronal Excitability by Regulating the Calcium-Calcineurin-NFATc4 Signaling Pathway. J Biol Chem 2016; 291:17369-81. [PMID: 27307045 PMCID: PMC5016134 DOI: 10.1074/jbc.m115.708883] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Indexed: 11/06/2022] Open
Abstract
Neuritin is an important neurotrophin that regulates neural development, synaptic plasticity, and neuronal survival. Elucidating the downstream molecular signaling is important for potential therapeutic applications of neuritin in neuronal dysfunctions. We previously showed that neuritin up-regulates transient potassium outward current (IA) subunit Kv4.2 expression and increases IA densities, in part by activating the insulin receptor signaling pathway. Molecular mechanisms of neuritin-induced Kv4.2 expression remain elusive. Here, we report that the Ca(2+)/calcineurin (CaN)/nuclear factor of activated T-cells (NFAT) c4 axis is required for neuritin-induced Kv4.2 transcriptional expression and potentiation of IA densities in cerebellum granule neurons. We found that neuritin elevates intracellular Ca(2+) and increases Kv4.2 expression and IA densities; this effect was sensitive to CaN inhibition and was eliminated in Nfatc4(-/-) mice but not in Nfatc2(-/-) mice. Stimulation with neuritin significantly increased nuclear accumulation of NFATc4 in cerebellum granule cells and HeLa cells, which expressed IR. Furthermore, NFATc4 was recruited to the Kv4.2 gene promoter loci detected by luciferase reporter and chromatin immunoprecipitation assays. More importantly, data obtained from cortical neurons following adeno-associated virus-mediated overexpression of neuritin indicated that reduced neuronal excitability and increased formation of dendritic spines were abrogated in the Nfatc4(-/-) mice. Together, these data demonstrate an indispensable role for the CaN/NFATc4 signaling pathway in neuritin-regulated neuronal functions.
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Affiliation(s)
- Jin-Jing Yao
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
| | - Qian-Ru Zhao
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
| | - Dong-Dong Liu
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
| | - Chi-Wing Chow
- the Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York 10461
| | - Yan-Ai Mei
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
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10
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Vihma H, Luhakooder M, Pruunsild P, Timmusk T. Regulation of different human NFAT isoforms by neuronal activity. J Neurochem 2016; 137:394-408. [PMID: 26851544 DOI: 10.1111/jnc.13568] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/04/2016] [Accepted: 01/29/2016] [Indexed: 12/30/2022]
Abstract
Nuclear factor of activated T-cells (NFAT) is a family of transcription factors comprising four calcium-regulated members: NFATc1, NFATc2, NFATc3, and NFATc4. Upon activation by the calcium-dependent phosphatase calcineurin (CaN), NFATs translocate from cytosol to the nucleus and regulate their target genes, which in the nervous system are involved in axon growth, synaptic plasticity, and neuronal survival. We have shown previously that there are a number of different splice variants of NFAT genes expressed in the brain. Here, we studied the subcellular localizations and transactivation capacities of alternative human NFAT isoforms in rat primary cortical or hippocampal neurons in response to membrane depolarization and compared the induced transactivation levels in neurons to those obtained from HEK293 cells in response to calcium signaling. We confirm that in neurons the translocation to the nucleus of all NFAT isoforms is reliant on the activity of CaN. However, our results suggest that both the regulation of subcellular localization and transcriptional activity of NFAT proteins in neurons is isoform specific. We show that in primary hippocampal neurons NFATc2 isoforms have very fast translocation kinetics, whereas NFATc4 isoforms translocate relatively slowly to the nucleus. Moreover, we demonstrate that the strongest transcriptional activators in HEK293 cells are NFATc1 and NFATc3, but in neurons NFATc3 and NFATc4 lead to the highest induction, and NFATc2 and NFATc1 display isoform-specific transcription activation capacities. Altogether, our results indicate that the effects of calcium signaling on the action of NFAT proteins are isoform-specific and can differ between cell types. We show that the effects of calcium signaling on the action of NFAT proteins are isoform-specific and differ between cell types. Although nuclear localization of all NFAT isoforms in neurons requires calcineurin, the subcellular distributions, neuronal activity-induced nuclear translocation extent and kinetics, and transcription activation capacities of alternative NFAT proteins vary.
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Affiliation(s)
- Hanna Vihma
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Mirjam Luhakooder
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Priit Pruunsild
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Tõnis Timmusk
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
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Iqbal S, Hayman EG, Hong C, Stokum JA, Kurland DB, Gerzanich V, Simard JM. Inducible nitric oxide synthase (NOS-2) in subarachnoid hemorrhage: Regulatory mechanisms and therapeutic implications. Brain Circ 2016; 2:8-19. [PMID: 27774520 PMCID: PMC5074544 DOI: 10.4103/2394-8108.178541] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aneurysmal subarachnoid hemorrhage (SAH) typically carries a poor prognosis. Growing evidence indicates that overabundant production of nitric oxide (NO) may be responsible for a large part of the secondary injury that follows SAH. Although SAH modulates the activity of all three isoforms of nitric oxide synthase (NOS), the inducible isoform, NOS-2, accounts for a majority of NO-mediated secondary injuries after SAH. Here, we review the indispensable physiological roles of NO that must be preserved, even while attempting to downmodulate the pathophysiologic effects of NO that are induced by SAH. We examine the effects of SAH on the function of the various NOS isoforms, with a particular focus on the pathological effects of NOS-2 and on the mechanisms responsible for its transcriptional upregulation. Finally, we review interventions to block NOS-2 upregulation or to counteract its effects, with an emphasis on the potential therapeutic strategies to improve outcomes in patients afflicted with SAH. There is still much to be learned regarding the apparently maladaptive response of NOS-2 and its harmful product NO in SAH. However, the available evidence points to crucial effects that, on balance, are adverse, making the NOS-2/NO/peroxynitrite axis an attractive therapeutic target in SAH.
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Affiliation(s)
- Sana Iqbal
- Department of Neurosurgery, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Erik G Hayman
- Department of Neurosurgery, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Caron Hong
- Department of Anesthesiology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Jesse A Stokum
- Department of Neurosurgery, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - David B Kurland
- Department of Neurosurgery, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - J Marc Simard
- Department of Neurosurgery, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Pathology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
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12
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Toll-Like Receptors Promote Mitochondrial Translocation of Nuclear Transcription Factor Nuclear Factor of Activated T-Cells in Prolonged Microglial Activation. J Neurosci 2015. [PMID: 26224862 DOI: 10.1523/jneurosci.2455-14.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Microglia are resident macrophages in the CNS that scavenge pathogens, dying cells, and molecules using pattern recognition Toll-like receptors (TLRs). Nuclear factor of activated T-cells (NFAT) family transcription factors also regulate inflammatory responses in microglia. However, whether there exists cross talk between TLR and NFAT signaling is unclear. Here we show that chronic activation of murine microglia by prolonged stimulation of Toll-like receptor 4 (TLR4) ligand lipopolysaccharides (LPSs) leads to unexpected translocation of NFAT1 into mitochondria. This mitochondrial import of NFAT1 is independent of calcium/calcineurin signaling. Instead, inhibition of Toll/interleukin 1 receptor domain-containing adapter-inducing interferon-β (TRIF) pathway blocks the mitochondrial translocation of NFAT1. Functionally, inhibition of NFAT1 reduces the TRIF-mediated expression of interferon-β and compromises the production of ATP and reactive oxygen species in LPS-treated microglia. Therefore, our findings reveal a new inflammatory signaling pathway that links TLR with NFAT in regulating cytokine production and mitochondrial activity during chronic microglial activation. SIGNIFICANCE STATEMENT Nuclear factor of activated T-cells (NFAT) family transcription factors are known to undergo nuclear translocation in response to inflammatory stimulation. In this study, we uncovered a surprise transportation of NFATs into mitochondria in microglia after a prolonged treatment with bacteria endotoxin lipopolysaccharides (LPSs). LPSs activated Toll-like receptor 4 and its downstream Toll/interleukin 1 receptor-domain-containing adapter-inducing interferon-β (TRIF) to regulate the mitochondrial translocation of NFAT in microglia, whereas genetic inhibition of NFAT1 compromised TRIF-mediated cytokine production and reduced ATP and reactive oxygen species generation. These findings reveal a previously undescribed mitochondrial translocation of NFAT in microglia responding to extended activation of Toll-like receptor-mediated signaling transduction pathways.
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13
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Mao M, Montgomery JM, Kubke MF, Thorne PR. The Structural Development of the Mouse Dorsal Cochlear Nucleus. J Assoc Res Otolaryngol 2015; 16:473-86. [PMID: 25985874 DOI: 10.1007/s10162-015-0520-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 04/20/2015] [Indexed: 12/19/2022] Open
Abstract
The dorsal cochlear nucleus (DCN) is a major subdivision of the mammalian cochlear nucleus (CN) that is thought to be involved in sound localization in the vertical plane and in feature extraction of sound stimuli. The main principal cell type (pyramidal cells) integrates auditory and non-auditory inputs, which are considered to be important in performing sound localization tasks. This study aimed to investigate the histological development of the CD-1 mouse DCN, focussing on the postnatal period spanning the onset of hearing (P12). Fluorescent Nissl staining revealed that the three layers of the DCN were identifiable as early as P6 with subsequent expansion of all layers with age. Significant increases in the size of pyramidal and cartwheel cells were observed between birth and P12. Immunohistochemistry showed substantial changes in synaptic distribution during the first two postnatal weeks with subsequent maturation of the presumed mossy fibre terminals. In addition, GFAP immunolabelling identified several glial cell types in the DCN including the observation of putative tanycytes for the first time. Each glial cell type had specific spatial and temporal patterns of maturation with apparent rapid development during the first two postnatal weeks but little change thereafter. The rapid maturation of the structural organization and DCN components prior to the onset of hearing possibly reflects an influence from spontaneous activity originating in the cochlea/auditory nerve. Further refinement of these connections and development of the non-auditory connections may result from the arrival of acoustic input and experience dependent mechanisms.
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Affiliation(s)
- Miaomiao Mao
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand,
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14
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Rojanathammanee L, Floden AM, Manocha GD, Combs CK. Attenuation of microglial activation in a mouse model of Alzheimer's disease via NFAT inhibition. J Neuroinflammation 2015; 12:42. [PMID: 25889879 PMCID: PMC4355356 DOI: 10.1186/s12974-015-0255-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/25/2015] [Indexed: 12/21/2022] Open
Abstract
Background Amyloid β (Aβ) peptide is hypothesized to stimulate microglia to acquire their characteristic proinflammatory phenotype in Alzheimer’s disease (AD) brains. The specific mechanisms by which Aβ leads to microglial activation remain an area of interest for identifying attractive molecular targets for intervention. Based upon the fact that microglia express the proinflammatory transcription factor, nuclear factor of activated T cells (NFAT), we hypothesized that NFAT activity is required for the Aβ-stimulated microgliosis that occurs during disease. Methods Primary murine microglia cultures were stimulated with Aβ in the absence or presence of NFAT inhibitors, FK506 and tat-VIVIT peptide, to quantify secretion of cytokines, neurotoxins, or Aβ phagocytosis. A transgenic mouse model of AD, APP/PS1, was treated subcutaneously via mini-osmotic pumps with FK506 or tat-VIVIT to quantify effects on cytokines, microgliosis, plaque load, and memory. Results Expression of various NFAT isoforms was verified in primary murine microglia through Western blot analysis. Microglial cultures were stimulated with Aβ fibrils in the absence or presence of the NFAT inhibitors, FK506 and tat-VIVIT, to demonstrate that NFAT activity regulated Aβ phagocytosis, neurotoxin secretion, and cytokine secretion. Delivery of FK506 and tat-VIVIT to transgenic APP/PS1 mice attenuated spleen but not brain cytokine levels. However, FK506 and tat-VIVIT significantly attenuated both microgliosis and Aβ plaque load in treated mice compared to controls. Surprisingly, this did not correlate with changes in memory performance via T-maze testing. Conclusions Our findings suggest that development of specific NFAT inhibitors may offer promise as an effective strategy for attenuating the microgliosis and Aβ plaque deposition that occur in AD. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0255-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lalida Rojanathammanee
- Institute of Science, Suranaree University of Technology, 111 University Avenue, Suranaree Subdistric, Nakhon Ratchasima, 30000, Thailand. .,Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Neuroscience Building, Grand Forks, ND, 58203, USA.
| | - Angela M Floden
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Neuroscience Building, Grand Forks, ND, 58203, USA.
| | - Gunjan D Manocha
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Neuroscience Building, Grand Forks, ND, 58203, USA.
| | - Colin K Combs
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Neuroscience Building, Grand Forks, ND, 58203, USA.
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15
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Control of neuronal apoptosis by reciprocal regulation of NFATc3 and Trim17. Cell Death Differ 2014; 22:274-86. [PMID: 25215946 DOI: 10.1038/cdd.2014.141] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 07/08/2014] [Accepted: 08/04/2014] [Indexed: 12/18/2022] Open
Abstract
Neuronal apoptosis induced by survival factor deprivation is strongly regulated at the transcriptional level. Notably, the nuclear factor of activated T cell (NFAT) transcription factors have an important role in the control of the survival/death fate of neurons. However, the mechanisms that regulate NFAT activity in response to apoptotic stimuli and the target genes that mediate their effect on neuronal apoptosis are mostly unknown. In a previous study, we identified Trim17 as a crucial E3 ubiquitin ligase that is necessary and sufficient for neuronal apoptosis. Here, we show that Trim17 binds preferentially SUMOylated forms of NFATc3. Nonetheless, Trim17 does not promote the ubiquitination/degradation of NFATc3. NFAT transcription factors are regulated by calcium/calcineurin-dependent nuclear-cytoplasmic shuttling. Interestingly, Trim17 reduced by twofold the calcium-mediated nuclear localization of NFATc3 and, consistent with this, halved NFATc3 activity, as estimated by luciferase assays and by measurement of target gene expression. Trim17 also inhibited NFATc4 nuclear translocation and activity. NFATc4 is known to induce the expression of survival factors and, as expected, overexpression of NFATc4 protected cerebellar granule neurons from serum/KCl deprivation-induced apoptosis. Inhibition of NFATc4 by Trim17 may thus partially mediate the proapoptotic effect of Trim17. In contrast, overexpression of NFATc3 aggravated neuronal death, whereas knockdown of NFATc3 protected neurons from apoptosis. This proapoptotic effect of NFATc3 might be due to a feedback loop in which NFATc3, but not NFATc4, induces the transcription of the proapoptotic gene Trim17. Indeed, we found that overexpression or silencing of NFATc3, respectively, increased or decreased Trim17 levels, whereas NFATc4 had no significant effect on Trim17 expression. Moreover, we showed that NFATc3 binds to the promoter of the Trim17 gene together with c-Jun. Therefore, our results describe a novel mechanism regulating NFAT transcription factors beyond the calcium/calcineurin-dependent pathway and provide a possible explanation for the opposite effects of NFATc3 and NFATc4 on neuronal apoptosis.
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16
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Furman JL, Norris CM. Calcineurin and glial signaling: neuroinflammation and beyond. J Neuroinflammation 2014; 11:158. [PMID: 25199950 PMCID: PMC4172899 DOI: 10.1186/s12974-014-0158-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 08/22/2014] [Indexed: 12/11/2022] Open
Abstract
Similar to peripheral immune/inflammatory cells, neuroglial cells appear to rely on calcineurin (CN) signaling pathways to regulate cytokine production and cellular activation. Several studies suggest that harmful immune/inflammatory responses may be the most impactful consequence of aberrant CN activity in glial cells. However, newly identified roles for CN in glutamate uptake, gap junction regulation, Ca2+ dyshomeostasis, and amyloid production suggest that CN's influence in glia may extend well beyond neuroinflammation. The following review will discuss the various actions of CN in glial cells, with particular emphasis on astrocytes, and consider the implications for neurologic dysfunction arising with aging, injury, and/or neurodegenerative disease.
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17
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Luo J, Sun L, Lin X, Liu G, Yu J, Parisiadou L, Xie C, Ding J, Cai H. A calcineurin- and NFAT-dependent pathway is involved in α-synuclein-induced degeneration of midbrain dopaminergic neurons. Hum Mol Genet 2014; 23:6567-74. [PMID: 25051958 DOI: 10.1093/hmg/ddu377] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Parkinson's disease (PD), the most common degenerative movement disorder, is caused by a preferential loss of midbrain dopaminergic (mDA) neurons. Both α-synuclein (α-syn) missense and multiplication mutations have been linked to PD. However, the underlying intracellular signalling transduction pathways of α-syn-mediated mDA neurodegeneration remain elusive. Here, we show that transgenic expression of PD-related human α-syn A53T missense mutation promoted calcineurin (CN) activity and the subsequent nuclear translocation of nuclear factor of activated T cells (NFATs) in mDA neurons. α-syn enhanced the phosphatase activity of CN in both cell-free assays and cell lines transfected with either human wild-type or A53T α-syn. Furthermore, overexpression of α-syn A53T mutation significantly increased the CN-dependent nuclear import of NFATc3 in the mDA neurons of transgenic mice. More importantly, a pharmacological inhibition of CN by cyclosporine A (CsA) ameliorated the α-syn-induced loss of mDA neurons. These findings demonstrate an active involvement of CN- and NFAT-mediated signalling pathway in α-syn-mediated degeneration of mDA neurons in PD.
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Affiliation(s)
- Jing Luo
- Department of Biochemistry and Molecular Biology, Beijing Normal University, Gene Engineering and Biotechnology Beijing Key Laboratory, Beijing 100875, China, Transgenics Section and and
| | | | | | | | - Jia Yu
- Transgenics Section and and
| | | | | | - Jinhui Ding
- Bioinformatics Core, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
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18
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Ran Y, Wu H, Wei L, Yu X, Chen J, Li S, Zhang L, Lou J, Zhu D. NFATc3 pathway participates in the process that 15-LO/15-HETE protects pulmonary artery smooth muscle cells against apoptosis during hypoxia. J Recept Signal Transduct Res 2014; 34:270-82. [DOI: 10.3109/10799893.2014.917322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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19
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Liu X, Zhao Q, Peng X, Xia S, Shen W, Zong Y, Cheng J, Wu W, Zhang M, Du F, Xu W, Qian H, Shao Q. PTD-mediated intracellular delivery of mutant NFAT minimum DNA binding domain inhibited the proliferation of T cells. Int Immunopharmacol 2014; 19:110-8. [DOI: 10.1016/j.intimp.2014.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 12/31/2013] [Accepted: 01/03/2014] [Indexed: 12/01/2022]
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20
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Yan HQ, Shin SS, Ma X, Li Y, Dixon CE. Differential effect of traumatic brain injury on the nuclear factor of activated T Cells C3 and C4 isoforms in the rat hippocampus. Brain Res 2013; 1548:63-72. [PMID: 24389074 DOI: 10.1016/j.brainres.2013.12.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 10/25/2022]
Abstract
The interaction between the phosphatase calcineurin and transcription factor nuclear factor of activated T cells (NFAT) plays an important role numerous signaling and the regulatory events. Although NFAT is mostly known for its transcription function in the immune system, NFAT also has essential functions even in the central nervous system (CNS). The effects of traumatic brain injury (TBI) on NFAT are currently unknown. To determine if there is an alteration in NFAT after TBI, we examined NFATc3 and c4 levels at 6 h, 1 day, 1 week, 2 weeks and 4 weeks post injury. Rats were anesthetized and surgically prepared for controlled cortical impact (CCI) injury or sham surgery. Semi-quantitative measurements of NFATc3 and c4 in the hippocampal homogenates from injured and sham rats sacrificed at the appropriate time after injury were assessed using Western blot analysis. After TBI insult, in the hippocampus ipsilateral to the injury, NFATc3 expression levels were decreased both in the cytoplasmic and nuclear fractions. However, NFATc4 expression levels were increased in the cytoplasmic fraction but decreased in the nuclear fraction. Double labeling (with NeuN and GFAP) immunohistochemistry revealed that NFATc3 was expressed in subset of astrocytes and NFATc4 was expressed primarily in neurons. These differential responses in NFATc3 and c4 expression after TBI insult may indicate long-term changes in hippocampal excitability and may contribute to behavioral deficits. Further study is warranted to illustrate the role of NFATc3 and c4 in the setting of TBI.
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Affiliation(s)
- Hong Q Yan
- Department of Neurological Surgery, Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Samuel S Shin
- Department of Neurological Surgery, Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Xiecheng Ma
- Department of Neurological Surgery, Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Youming Li
- Department of Neurological Surgery, Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - C Edward Dixon
- Department of Neurological Surgery, Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260.,Veterans Affairs Pittsburgh Healthcare System Pittsburgh, PA 15240
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21
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Spatiotemporal changes in NFATc4 expression of retinal ganglion cells after light-induced damage. J Mol Neurosci 2013; 53:69-77. [PMID: 24362677 DOI: 10.1007/s12031-013-0198-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 11/28/2013] [Indexed: 12/27/2022]
Abstract
Nuclear factor of activated T cells, cytoplasmic 4 (NFATc4) is one of the four members of the NFAT family, which were described first as essential components of T cells activation and lately as important regulators for the initiation and coordination of the immune response, including B cells and natural killer cells. Accumulating evidence has demonstrated that NFATc4 exerted a pro-apoptotic effect in the pathogenesis of various experimental central nervous system diseases by upregulating Fas ligand (FasL) levels. However, the function of NFATc4 in the retina is still with limited acquaintance. To investigate whether NFATc4 is involved in retinal neuron apoptosis, we performed a light-induced retinal damage model in adult rats. A significant upregulation of NFATc4 was detected in the retina after light-induced damage by using Western blotting and reverse transcriptase PCR (RT-PCR). Besides this, NFATc4 was observed to be localized mainly in the retinal ganglion cells (RGCs). In addition, the expression patterns of active caspase-3, active caspase-8, and FasL were parallel with that of NFATc4. We also found the co-localization of NFATc4 with active caspase-3 and FasL in RGCs after light exposure. Collectively, we hypothesized that NFATc4 might participate in RGCs apoptosis by upregulating FasL levels.
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22
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Up-regulation of NFATc4 Involves in Neuronal Apoptosis Following Intracerebral Hemorrhage. Cell Mol Neurobiol 2013; 33:893-905. [DOI: 10.1007/s10571-013-9955-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/25/2013] [Indexed: 11/27/2022]
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23
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Murase S. Signal transducer and activator of transcription 3 (STAT3) degradation by proteasome controls a developmental switch in neurotrophin dependence. J Biol Chem 2013; 288:20151-61. [PMID: 23733189 DOI: 10.1074/jbc.m113.470583] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neonatal brains develop through a program that eliminates about half of the neurons. During this period, neurons depend on neurotrophins for their survival. Recently, we reported that, at the conclusion of the naturally occurring death period, neurons become neurotrophin-independent and, further, that this developmental switch is achieved by the emergence of a second survival pathway mediated by signal transducer and activator of transcription 3 (STAT3). Here I show that calcineurin plays a key role in controlling the developmental switch in mouse hippocampal neurons. Calcineurin promotes the degradation of STAT3 via the ubiquitin-proteasome pathway. Inhibition of calcineurin acutely increases total levels of STAT3 as well as its activated forms, resulting in decreased levels of the tumor suppressor p53 and its proapoptotic target, Bax. In vivo and in vitro, calcineurin regulates levels of STAT3 and neurotrophin dependence. TMF/ARA 160 (TATA element modulatory factor/androgen receptor co-activator 160), the key mediator of STAT3 ubiquitination, is required for calcineurin-dependent STAT3 degradation. Thus, these results show that the ubiquitin-proteasome pathway controls the critical developmental switch of neurotrophin dependence in the newborn hippocampus.
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Affiliation(s)
- Sachiko Murase
- Laboratory of Molecular Biology, NINDS, National Institutes of Health, Bethesda, Maryland 20892, USA.
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24
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Rojanathammanee L, Puig KL, Combs CK. Pomegranate polyphenols and extract inhibit nuclear factor of activated T-cell activity and microglial activation in vitro and in a transgenic mouse model of Alzheimer disease. J Nutr 2013; 143:597-605. [PMID: 23468550 PMCID: PMC3738232 DOI: 10.3945/jn.112.169516] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Alzheimer disease (AD) brain is characterized by extracellular plaques of amyloid β (Aβ) peptide with reactive microglia. This study aimed to determine whether a dietary intervention could attenuate microgliosis. Memory was assessed in 12-mo-old male amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice via Barnes maze testing followed by division into either a control-fed group provided free access to normal chow and water or a treatment group provided free access to normal chow and drinking water supplemented with pomegranate extract (6.25 mL/L) for 3 mo followed by repeat Barnes maze testing for both groups. Three months of pomegranate feeding decreased the path length to escape of mice compared with their initial 12-mo values (P < 0.05) and their control-fed counterparts (P < 0.05). Brains of the 3-mo study pomegranate-fed mice had lower tumor necrosis factor α (TNF-α) concentrations (P < 0.05) and lower nuclear factor of activated T-cell (NFAT) transcriptional activity (P < 0.05) compared with controls. Brains of the 3-mo pomegranate or control mice were also compared with an additional control group of 12-mo-old mice for histologic analysis. Immunocytochemistry showed that pomegranate- but not control-fed mice had attenuated microgliosis (P < 0.05) and Aβ plaque deposition (P < 0.05) compared with 12-mo-old mice. An additional behavioral study again used 12-mo-old male APP/PS1 mice tested by T-maze followed by division into a control group provided with free access to normal chow and sugar supplemented drinking water or a treatment group provided with normal chow and pomegranate extract-supplemented drinking water (6.25 mL/L) for 1 mo followed by repeat T-maze testing in both groups. One month of pomegranate feeding increased spontaneous alternations versus control-fed mice (P < 0.05). Cell culture experiments verified that 2 polyphenol components of pomegranate extract, punicalagin and ellagic acid, attenuated NFAT activity in a reporter cell line (P < 0.05) and decreased Aβ-stimulated TNF-α secretion by murine microglia (P < 0.05). These data indicate that dietary pomegranate produces brain antiinflammatory effects that may attenuate AD progression.
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25
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Ulrich JD, Kim MS, Houlihan PR, Shutov LP, Mohapatra DP, Strack S, Usachev YM. Distinct activation properties of the nuclear factor of activated T-cells (NFAT) isoforms NFATc3 and NFATc4 in neurons. J Biol Chem 2012; 287:37594-609. [PMID: 22977251 DOI: 10.1074/jbc.m112.365197] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The Ca(2+)/calcineurin-dependent transcription factor NFAT (nuclear factor of activated T-cells) is implicated in regulating dendritic and axonal development, synaptogenesis, and neuronal survival. Despite the increasing appreciation for the importance of NFAT-dependent transcription in the nervous system, the regulation and function of specific NFAT isoforms in neurons are poorly understood. Here, we compare the activation of NFATc3 and NFATc4 in hippocampal and dorsal root ganglion neurons following electrically evoked elevations of intracellular Ca(2+) concentration ([Ca(2+)](i)). We find that NFATc3 undergoes rapid dephosphorylation and nuclear translocation that are essentially complete within 20 min, although NFATc4 remains phosphorylated and localized to the cytosol, only exhibiting nuclear localization following prolonged (1-3 h) depolarization. Knocking down NFATc3, but not NFATc4, strongly diminished NFAT-mediated transcription induced by mild depolarization in neurons. By analyzing NFATc3/NFATc4 chimeras, we find that the region containing the serine-rich region-1 (SRR1) mildly affects initial NFAT translocation, although the region containing the serine-proline repeats is critical for determining the magnitude of NFAT activation and nuclear localization upon depolarization. Knockdown of glycogen synthase kinase 3β (GSK3β) significantly increased the depolarization-induced nuclear localization of NFATc4. In contrast, inhibition of p38 or mammalian target of rapamycin (mTOR) kinases had no significant effect on nuclear import of NFATc4. Thus, electrically evoked [Ca(2+)](i) elevation in neurons rapidly and strongly activates NFATc3, whereas activation of NFATc4 requires a coincident increase in [Ca(2+)](i) and suppression of GSK3β, with differences in the serine-proline-containing region giving rise to these distinct activation properties of NFATc3 and NFATc4.
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Affiliation(s)
- Jason D Ulrich
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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Inhibition of the NFAT pathway alleviates amyloid β neurotoxicity in a mouse model of Alzheimer's disease. J Neurosci 2012; 32:3176-92. [PMID: 22378890 DOI: 10.1523/jneurosci.6439-11.2012] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Amyloid β (Aβ) peptides, the main pathological species associated with Alzheimer's disease (AD), disturb intracellular calcium homeostasis, which in turn activates the calcium-dependent phosphatase calcineurin (CaN). CaN activation induced by Aβ leads to pathological morphological changes in neurons, and overexpression of constitutively active calcineurin is sufficient to generate a similar phenotype, even without Aβ. Here, we tested the hypothesis that calcineurin mediates neurodegenerative effects via activation of the nuclear transcription factor of activated T-cells (NFAT). We found that both spine loss and dendritic branching simplification induced by Aβ exposure were mimicked by constitutively active NFAT, and abolished when NFAT activation was blocked using the genetically encoded inhibitor VIVIT. When VIVIT was specifically addressed to the nucleus, identical beneficial effects were observed, thus enforcing the role of NFAT transcriptional activity in Aβ-related neurotoxicity. In vivo, when VIVIT or its nuclear counterpart were overexpressed in a transgenic model of Alzheimer's disease via a gene therapy approach, the spine loss and neuritic abnormalities observed in the vicinity of amyloid plaques were blocked. Overall, these results suggest that NFAT/calcineurin transcriptional cascades contribute to Aβ synaptotoxicity, and may provide a new specific set of pathways for neuroprotective strategies.
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27
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Luoma JI, Kelley BG, Mermelstein PG. Progesterone inhibition of voltage-gated calcium channels is a potential neuroprotective mechanism against excitotoxicity. Steroids 2011; 76:845-55. [PMID: 21371490 PMCID: PMC3129396 DOI: 10.1016/j.steroids.2011.02.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 01/26/2011] [Accepted: 02/16/2011] [Indexed: 12/12/2022]
Abstract
The therapeutic use of progesterone following traumatic brain injury has recently entered phase III clinical trials as a means of neuroprotection. Although it has been hypothesized that progesterone protects against calcium overload following excitotoxic shock, the exact mechanisms underlying the beneficial effects of progesterone have yet to be determined. We found that therapeutic concentrations of progesterone to be neuroprotective against depolarization-induced excitotoxicity in cultured striatal neurons. Through use of calcium imaging, electrophysiology and the measurement of changes in activity-dependent gene expression, progesterone was found to block calcium entry through voltage-gated calcium channels, leading to alterations in the signaling of the activity-dependent transcription factors NFAT and CREB. The effects of progesterone were highly specific to this steroid hormone, although they did not appear to be receptor mediated. In addition, progesterone did not inhibit AMPA or NMDA receptor signaling. This analysis regarding the effect of progesterone on calcium signaling provides both a putative mechanism by which progesterone acts as a neuroprotectant, as well as affords a greater appreciation for its potential far-reaching effects on cellular function.
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Affiliation(s)
- Jessie I Luoma
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Brooke G Kelley
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Paul G Mermelstein
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Yu YM, Gibbs KM, Davila J, Campbell N, Sung S, Todorova TI, Otsuka S, Sabaawy HE, Hart RP, Schachner M. MicroRNA miR-133b is essential for functional recovery after spinal cord injury in adult zebrafish. Eur J Neurosci 2011; 33:1587-97. [PMID: 21447094 DOI: 10.1111/j.1460-9568.2011.07643.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) play important roles during development and also in adult organisms by regulating the expression of multiple target genes. Here, we studied the function of miR-133b during zebrafish spinal cord regeneration and show upregulation of miR-133b expression in regenerating neurons of the brainstem after transection of the spinal cord. miR-133b has been shown to promote tissue regeneration in other tissue, but its ability to do so in the nervous system has yet to be tested. Inhibition of miR-133b expression by antisense morpholino (MO) application resulted in impaired locomotor recovery and reduced regeneration of axons from neurons in the nucleus of the medial longitudinal fascicle, superior reticular formation and intermediate reticular formation. miR-133b targets the small GTPase RhoA, which is an inhibitor of axonal growth, as well as other neurite outgrowth-related molecules. Our results indicate that miR-133b is an important determinant in spinal cord regeneration of adult zebrafish through reduction in RhoA protein levels by direct interaction with its mRNA. While RhoA has been studied as a therapeutic target in spinal cord injury, this is the first demonstration of endogenous regulation of RhoA by a microRNA that is required for spinal cord regeneration in zebrafish. The ability of miR-133b to suppress molecules that inhibit axon regrowth may underlie the capacity for adult zebrafish to recover locomotor function after spinal cord injury.
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Affiliation(s)
- Young-Mi Yu
- W. M. Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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29
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Abdul HM, Baig I, LeVine H, Guttmann RP, Norris CM. Proteolysis of calcineurin is increased in human hippocampus during mild cognitive impairment and is stimulated by oligomeric Abeta in primary cell culture. Aging Cell 2011; 10:103-13. [PMID: 20969723 PMCID: PMC3021581 DOI: 10.1111/j.1474-9726.2010.00645.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Recent reports demonstrate that the activation and interaction of the protease calpain (CP) and the protein phosphatase calcineurin (CN) are elevated in the late stages of Alzheimer's disease (AD). However, the extent to which CPs and CN interact during earlier stages of disease progression remains unknown. Here, we investigated CP and CN protein levels in cytosolic, nuclear, and membrane fractions prepared from human postmortem hippocampal tissue from aged non-demented subjects, and subjects diagnosed with mild cognitive impairment (MCI). The results revealed a parallel increase in CP I and the 48 kDa CN-Aα (ΔCN-Aα48) proteolytic fragment in cytosolic fractions during MCI. In primary rat hippocampal cultures, CP-dependent proteolysis and activation of CN was stimulated by application of oligomeric Aβ((1-42)) peptides. Deleterious effects of Aβ on neuronal morphology were reduced by blockade of either CP or CN. NMDA-type glutamate receptors, which help regulate cognition and neuronal viability, and are modulated by CPs and CN, were also investigated in human hippocampus. Relative to controls, MCI subjects showed significantly greater proteolytic levels of the NR2B subunit. Within subjects, the extent of NR2B proteolysis was strongly correlated with the generation of ΔCN-Aα48 in the cytosol. A similar proteolytic pattern for NR2B was also observed in primary rat hippocampal cultures treated with oligomeric Aβ and prevented by inhibition of CP or CN. Together, the results demonstrate that the activation and interaction of CPs and CN are increased early in cognitive decline associated with AD and may help drive other pathologic processes during disease progression.
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Affiliation(s)
- Hafiz Mohmmad Abdul
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
| | - Irfan Baig
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - Harry LeVine
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - Rodney P Guttmann
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Graduate Center for Gerontology, University of Kentucky, Lexington, KY 40536
| | - Christopher M. Norris
- The Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY40536
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30
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Nagamoto-Combs K, Combs CK. Microglial phenotype is regulated by activity of the transcription factor, NFAT (nuclear factor of activated T cells). J Neurosci 2010; 30:9641-6. [PMID: 20631193 PMCID: PMC2914496 DOI: 10.1523/jneurosci.0828-10.2010] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 06/04/2010] [Accepted: 06/12/2010] [Indexed: 11/21/2022] Open
Abstract
The transcription factor family, nuclear factor of activated T cells (NFAT), regulates immune cell phenotype. Four different calcium/calmodulin-regulated isoforms have been identified in the periphery, but isoform expression in microglia, the resident immune cells of the CNS, has not been fully defined. In this study microglial NFAT isoform expression and involvement in regulating inflammatory responses in murine primary microglia culture was examined. Western blot analysis demonstrated robust detection of NFATc1 and c2 isoforms in microglia. Electrophoretic mobility shift assays demonstrated increased NFAT-DNA binding from nuclear extracts of lipopolysaccharide (LPS) stimulated microglia. Moreover, LPS-stimulated microglia behaved similarly to T cell receptor agonist antibody-stimulated Jurkat cells demonstrating a transient increase in NFAT-driven luciferase reporter gene expression. LPS-induced NFAT-luciferase activity in microglia was attenuated by pretreatment with tat-VIVIT, a cell-permeable NFAT inhibitory peptide. Furthermore, LPS-mediated secretion of microglial cytokines, TNF-alpha and MCP-1, was decreased by treatment with tat-VIVIT but not with tat-VEET, a negative control peptide. These results demonstrate that NFAT plays a role in regulating proinflammatory responses in cultured murine microglia.
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Affiliation(s)
- Kumi Nagamoto-Combs
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Colin K. Combs
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
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31
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Gómez-Sintes R, Lucas JJ. NFAT/Fas signaling mediates the neuronal apoptosis and motor side effects of GSK-3 inhibition in a mouse model of lithium therapy. J Clin Invest 2010; 120:2432-45. [PMID: 20530871 DOI: 10.1172/jci37873] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 04/21/2010] [Indexed: 12/12/2022] Open
Abstract
Use of lithium, the mainstay for treatment of bipolar disorder, is limited by its frequent neurological side effects and its risk for overdose-induced toxicity. Recently, lithium has also been proposed as a treatment for Alzheimer disease and other neurodegenerative conditions, but clinical trials have been hampered by its prominent side effects in the elderly. The mechanisms underlying both the positive and negative effects of lithium are not fully known. Lithium inhibits glycogen synthase kinase-3 (GSK-3) in vivo, and we recently reported neuronal apoptosis and motor deficits in dominant-negative GSK-3-transgenic mice. We hypothesized that therapeutic levels of lithium could also induce neuronal loss through GSK-3 inhibition. Here we report induction of neuronal apoptosis in various brain regions and the presence of motor deficits in mice treated chronically with lithium. We found that GSK-3 inhibition increased translocation of nuclear factor of activated T cells c3/4 (NFATc3/4) transcription factors to the nucleus, leading to increased Fas ligand (FasL) levels and Fas activation. Lithium-induced apoptosis and motor deficits were absent when NFAT nuclear translocation was prevented by cyclosporin A administration and in Fas-deficient lpr mice. The results of these studies suggest a mechanism for lithium-induced neuronal and motor toxicity. These findings may enable the development of combined therapies that diminish the toxicities of lithium and possibly other GSK-3 inhibitors and extend their potential to the treatment of Alzheimer disease and other neurodegenerative conditions.
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Affiliation(s)
- Raquel Gómez-Sintes
- Centro de Biología Molecular Severo Ochoa (CBM SO), CSIC/UAM, 28049 Madrid, Spain
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32
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Butterick TA, Igbavboa U, Eckert GP, Sun GY, Weisman GA, Müller WE, Wood WG. Simvastatin stimulates production of the antiapoptotic protein Bcl-2 via endothelin-1 and NFATc3 in SH-SY5Y cells. Mol Neurobiol 2010; 41:384-91. [PMID: 20369390 PMCID: PMC3075856 DOI: 10.1007/s12035-010-8122-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Accepted: 03/17/2010] [Indexed: 01/11/2023]
Abstract
The use of statins for the prevention or treatment of different neurodegenerative diseases has generated considerable interest albeit with some controversy. Mechanisms of statin-induced neuroprotection are not well understood. Recently, we reported that simvastatin stimulated neuronal gene expression and protein levels of the major antiapoptotic protein Bcl-2 in vivo and in vitro; suppression of Bcl-2 in SH-SY5Y cells reduced simvastatin neuroprotection; effects were independent of cholesterol and other products of the 3-hydroxy-3-methylglutaryl-CoA reductase pathway. Endothelin-1 (ET-1) can increase Bcl-2 abundance via the transcription factor nuclear factor of activated thymocytes (NFATc), and simvastatin was reported to increase ET-1 gene expression. We tested the hypothesis that simvastatin stimulation of Bcl-2 involves up-regulation of ET-1 and binding of NFATc to Bcl-2 promoter sites in SH-SY5Y human neuroblastoma cells. Simvastatin increased both intracellular and secreted ET-1 protein levels. Exogenous ET-1 increased Bcl-2 protein abundance, which was inhibited by ET-1 receptor antagonists. Simvastatin increased translocation of NFATc3 to the nucleus while reducing nuclear NFATc1 and having no effect on NFATc4. Endothelin-1 also increased NFATc3 levels in the nucleus, and this increase was inhibited by ET-1 receptor antagonists. Treatment of cells with simvastatin stimulated binding of NFATc3 to the Bcl-2 promoter. We report novel findings showing that up-regulation of Bcl-2 by simvastatin involves ET-1 and the transcription factor NFATc3. Discovering how statins can selectively alter a specific NFATc isoform that leads to an increase in an antiapoptotic protein will provide a new approach to understanding statin-induced neuroprotection and conditions outside the brain in which apoptosis contributes to pathophysiology.
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Affiliation(s)
- Tammy A. Butterick
- Department of Pharmacology, Geriatric Research Education and Clinical Center, VA Medical Center, University of Minnesota, Minneapolis, MN, USA
| | - Urule Igbavboa
- Department of Pharmacology, Geriatric Research Education and Clinical Center, VA Medical Center, University of Minnesota, Minneapolis, MN, USA
| | - Gunter P. Eckert
- Department of Pharmacology, BiocenterNiederursel, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Grace Y. Sun
- Department of Biochemistry, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, Canada
| | - Gary A. Weisman
- Department of Biochemistry, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, Canada
| | - Walter E. Müller
- Department of Pharmacology, BiocenterNiederursel, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - W. Gibson Wood
- Department of Pharmacology, Geriatric Research Education and Clinical Center, VA Medical Center, University of Minnesota, Minneapolis, MN, USA. Department of Pharmacology, University of Minnesota, 6-120 Jackson Hall, 321 Church Street, SE, Minneapolis, MN 55455, USA
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33
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Abdul HM, Furman JL, Sama MA, Mathis DM, Norris CM. NFATs and Alzheimer's Disease. MOLECULAR AND CELLULAR PHARMACOLOGY 2010; 2:7-14. [PMID: 20401186 DOI: 10.4255/mcpharmacol.10.02] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nuclear factor of activated T cells (NFAT) is a transcription factor that translocates from cytosol to nucleus following dephosphorylation by the Ca(2+)/calmodulin dependent protein phosphatase calcineurin (CN). In nervous tissue, aberrant CN signaling is increasingly linked to a variety of pathologic features associated with Alzheimer's disease (AD), including synaptic dysfunction, glial activation, and neuronal death. Consistent with this linkage, our recent work on postmortem human hippocampal tissue discovered increased nuclear accumulation of select NFAT isoforms at different stages of AD. Some of these changes occurred at the early stages of the disease process and/or paralleled diminishing cognitive status. In addition, inhibition of astrocytic NFAT activity in primary cultures of neurons and glia dampened glutamate levels and alleviated neuronal death in response to pathogenic amyloid-β peptides. In this article, we discuss our recent findings and expand upon the possible isoform specific contributions of NFATs to the progression of AD. We also consider the possible benefits of using NFAT inhibitors to treat AD and other neurodegenerative disorders, as well.
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34
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Abdul HM, Furman JL, Sama MA, Mathis DM, Norris CM. NFATs and Alzheimer's Disease. MOLECULAR AND CELLULAR PHARMACOLOGY 2010; 2:7-14. [PMID: 20401186 PMCID: PMC2855852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
Nuclear factor of activated T cells (NFAT) is a transcription factor that translocates from cytosol to nucleus following dephosphorylation by the Ca(2+)/calmodulin dependent protein phosphatase calcineurin (CN). In nervous tissue, aberrant CN signaling is increasingly linked to a variety of pathologic features associated with Alzheimer's disease (AD), including synaptic dysfunction, glial activation, and neuronal death. Consistent with this linkage, our recent work on postmortem human hippocampal tissue discovered increased nuclear accumulation of select NFAT isoforms at different stages of AD. Some of these changes occurred at the early stages of the disease process and/or paralleled diminishing cognitive status. In addition, inhibition of astrocytic NFAT activity in primary cultures of neurons and glia dampened glutamate levels and alleviated neuronal death in response to pathogenic amyloid-β peptides. In this article, we discuss our recent findings and expand upon the possible isoform specific contributions of NFATs to the progression of AD. We also consider the possible benefits of using NFAT inhibitors to treat AD and other neurodegenerative disorders, as well.
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Affiliation(s)
| | - Jennifer L. Furman
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky
| | - Michelle A. Sama
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky
| | - Diana M. Mathis
- Graduate Center for Gerontology, University of Kentucky, Lexington, Kentucky
| | - Christopher M. Norris
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky
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35
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Nuclear factor of activated T-cells isoform c4 (NFATc4/NFAT3) as a mediator of antiapoptotic transcription in NMDA receptor-stimulated cortical neurons. J Neurosci 2009; 29:15331-40. [PMID: 19955386 DOI: 10.1523/jneurosci.4873-09.2009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
During cortical development, when NR2B subunit is the major component of the NMDA glutamate receptors (NMDARs), moderate NMDAR activity supports neuronal survival at least in part by regulating gene transcription. We report that, in cultured cortical neurons from newborn rats, the NMDARs activated the calcium-responsive transcription regulator nuclear factor of activated T cells (NFAT). Moreover, in developing rat cortex, the NFAT isoforms c3 and c4 (NFATc3 and NFATc4) were expressed at relatively higher levels at postnatal day 7 (P7) than P21, overlapping with the period of NMDAR-dependent survival. In cultured cortical neurons, NFATc3 and NFATc4 were regulated at least in part by the NR2B NMDAR. Conversely, knockdown of NFATc4 but not NFATc3 induced cortical neuron apoptosis. Likewise, NFATc4 inhibition prevented antiapoptotic neuroprotection in response to exogenous NMDA. Expression of the brain-derived neurotrophic factor (BDNF) was reduced by NFATc4 inhibition. NFATc4 regulated transcription by the NMDAR-responsive bdnf promoter IV. In addition, NMDAR blockers including NR2B-selective once reduced BDNF expression in P7 cortex and cultured cortical neurons. Finally, exogenous BDNF rescued from the proapoptotic effects of NFATc4 inhibition. These results identify bdnf as one of the target genes for the antiapoptotic signaling by NMDAR-NFATc4. Thus, the previously unrecognized NMDAR-NFATc4-BDNF pathway contributes to the survival signaling network that supports cortical development.
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36
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Cognitive decline in Alzheimer's disease is associated with selective changes in calcineurin/NFAT signaling. J Neurosci 2009; 29:12957-69. [PMID: 19828810 DOI: 10.1523/jneurosci.1064-09.2009] [Citation(s) in RCA: 228] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Upon activation by calcineurin, the nuclear factor of activated T-cells (NFAT) translocates to the nucleus and guides the transcription of numerous molecules involved in inflammation and Ca(2+) dysregulation, both of which are prominent features of Alzheimer's disease (AD). However, NFAT signaling in AD remains relatively uninvestigated. Using isolated cytosolic and nuclear fractions prepared from rapid-autopsy postmortem human brain tissue, we show that NFATs 1 and 3 shifted to nuclear compartments in the hippocampus at different stages of neuropathology and cognitive decline, whereas NFAT2 remained unchanged. NFAT1 exhibited greater association with isolated nuclear fractions in subjects with mild cognitive impairment (MCI), whereas NFAT3 showed a strong nuclear bias in subjects with severe dementia and AD. Similar to NFAT1, calcineurin-Aalpha also exhibited a nuclear bias in the early stages of cognitive decline. But, unlike NFAT1 and similar to NFAT3, the nuclear bias for calcineurin became more pronounced as cognition worsened. Changes in calcineurin/NFAT3 were directly correlated to soluble amyloid-beta (Abeta((1-42))) levels in postmortem hippocampus, and oligomeric Abeta, in particular, robustly stimulated NFAT activation in primary rat astrocyte cultures. Oligomeric Abeta also caused a significant reduction in excitatory amino acid transporter 2 (EAAT2) protein levels in astrocyte cultures, which was blocked by NFAT inhibition. Moreover, inhibition of astrocytic NFAT activity in mixed cultures ameliorated Abeta-dependent elevations in glutamate and neuronal death. The results suggest that NFAT signaling is selectively altered in AD and may play an important role in driving Abeta-mediated neurodegeneration.
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37
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Mitochondrial Ca2+ cycling facilitates activation of the transcription factor NFAT in sensory neurons. J Neurosci 2009; 29:12101-14. [PMID: 19793968 DOI: 10.1523/jneurosci.3384-09.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Ca(2+)-dependent gene regulation controls many aspects of neuronal plasticity. Significant progress has been made toward understanding the roles of voltage- and ligand-gated Ca(2+) channels in triggering specific transcriptional responses. In contrast, the functional importance of Ca(2+) buffers and Ca(2+) transporters in neuronal gene regulation is less clear despite their critical contribution to the spatiotemporal control of Ca(2+) signals. Here we examined the role of mitochondrial Ca(2+) uptake and release in regulating the Ca(2+)-dependent transcription factor NFAT (nuclear factor of activated T-cells), which has been implicated in synaptic plasticity, axonal growth, and neuronal survival. Intense stimulation of sensory neurons by action potentials or TRPV1 agonists induced rapid activation and nuclear import of NFAT. Nuclear translocation of NFAT was associated with a characteristic prolonged [Ca(2+)](i) elevation (plateau) that resulted from Ca(2+) uptake by, and its subsequent release from, mitochondria. Measurements using a mitochondrial Ca(2+) indicator, mtPericam, showed that this process recruited mitochondria throughout the cell body, including the perinuclear region. [Ca(2+)](i) levels attained during the plateau phase were similar to or higher than those required for NFAT activation (200-300 nm). The elimination of the [Ca(2+)](i) plateau by blocking either mitochondrial Ca(2+) uptake via the uniporter or Ca(2+) release via the mitochondrial Na(+)/Ca(2+) exchanger strongly reduced nuclear import of NFAT. Furthermore, preventing Ca(2+) mobilization via the mitochondrial Na(+)/Ca(2+) exchanger diminished NFAT-mediated transcription. Collectively, these data implicate activity-induced Ca(2+) uptake and prolonged release from mitochondria as a novel regulatory mechanism in neuronal excitation-transcription coupling.
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38
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Haase G, Pettmann B, Raoul C, Henderson CE. Signaling by death receptors in the nervous system. Curr Opin Neurobiol 2009; 18:284-91. [PMID: 18725296 DOI: 10.1016/j.conb.2008.07.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 07/21/2008] [Indexed: 12/12/2022]
Abstract
Cell death plays an important role both in shaping the developing nervous system and in neurological disease and traumatic injury. In spite of their name, death receptors can trigger either cell death or survival and growth. Recent studies implicate five death receptors--Fas/CD95, TNFR1 (tumor necrosis factor receptor-1), p75NTR (p75 neurotrophin receptor), DR4, and DR5 (death receptors-4 and -5)--in different aspects of neural development or degeneration. Their roles may be neuroprotective in models of Parkinson's disease, or pro-apoptotic in ALS and stroke. Such different outcomes probably reflect the diversity of transcriptional and posttranslational signaling pathways downstream of death receptors in neurons and glia.
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Affiliation(s)
- Georg Haase
- Developmental Biology Institute of Marseille-Luminy, IBDML, CNRS UMR 6216, Marseille Cedex 09, France
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39
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Krasnova IN, Cadet JL. Methamphetamine toxicity and messengers of death. ACTA ACUST UNITED AC 2009; 60:379-407. [PMID: 19328213 DOI: 10.1016/j.brainresrev.2009.03.002] [Citation(s) in RCA: 420] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 03/16/2009] [Indexed: 12/11/2022]
Abstract
Methamphetamine (METH) is an illicit psychostimulant that is widely abused in the world. Several lines of evidence suggest that chronic METH abuse leads to neurodegenerative changes in the human brain. These include damage to dopamine and serotonin axons, loss of gray matter accompanied by hypertrophy of the white matter and microgliosis in different brain areas. In the present review, we summarize data on the animal models of METH neurotoxicity which include degeneration of monoaminergic terminals and neuronal apoptosis. In addition, we discuss molecular and cellular bases of METH-induced neuropathologies. The accumulated evidence indicates that multiple events, including oxidative stress, excitotoxicity, hyperthermia, neuroinflammatory responses, mitochondrial dysfunction, and endoplasmic reticulum stress converge to mediate METH-induced terminal degeneration and neuronal apoptosis. When taken together, these findings suggest that pharmacological strategies geared towards the prevention and treatment of the deleterious effects of this drug will need to attack the various pathways that form the substrates of METH toxicity.
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Affiliation(s)
- Irina N Krasnova
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, NIDA/NIH/DHHS, Baltimore, MD 21224, USA
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40
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Karnes HE, Kaiser CL, Durham D. Deafferentation-induced caspase-3 activation and DNA fragmentation in chick cochlear nucleus neurons. Neuroscience 2008; 159:804-18. [PMID: 19166907 DOI: 10.1016/j.neuroscience.2008.12.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 12/12/2008] [Accepted: 12/16/2008] [Indexed: 01/09/2023]
Abstract
Cochlea removal severs peripheral processes of cochlear ganglion cells and permanently abolishes afferent input to nucleus magnocellularis (NM) neurons. Deafferented chick NM neurons undergo a series of morphologic and metabolic changes, which ultimately trigger the death of 20%-40% of neurons. Previous studies suggested that this cell specific death involves activation of the intrinsic apoptotic pathway, including increased presence of cytochrome c and active caspase-9 in the cytoplasm of deafferented NM neurons. Interestingly, however, both markers were detected pan-neuronally, in both degenerating and surviving NM neurons [Wilkinson BL, Elam JS, Fadool DA, Hyson RL (2003) Afferent regulation of cytochrome-c and active caspase-9 in the avian cochlear nucleus. Neuroscience 120:1071-1079]. Here, we provide evidence for the increased appearance of late apoptotic indicators and describe novel characteristics of cell death in deafferented auditory neurons. Young broiler chickens were subjected to unilateral cochlea removal, and brainstem sections through NM were reacted for active caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Caspase-3 activation is observed in the cytoplasm of both dying and surviving deafferented NM neurons 24 h to 7 days following cochlea removal, suggesting that caspase-3, usually considered an "executioner" of apoptotic death, may also function as a "modulator" of death. In addition, we find that TUNEL labeling of degraded DNA is observed in deafferented NM. In contrast to upstream apoptotic markers, however, TUNEL labeling is restricted to a subpopulation of deafferented neurons. Twelve hours following cochlea removal, TUNEL labeling is observed as punctate accumulations within nuclei. Twenty-four hours following cochlea removal, TUNEL accumulates diffusely throughout neuronal cytoplasm in those neurons likely to die. This cytoplasmic TUNEL labeling may implicate mitochondrial nucleic acid degradation in the selective death of some deafferented NM neurons. Our study examines the subcellular distributions of two prominent apoptotic mediators, active caspase-3 and TUNEL, relative to known histochemical markers, in deafferented NM; provides new insight into the apoptotic mechanism of cell death; and proposes a role for mitochondrial DNA in deafferentation-induced cell death.
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Affiliation(s)
- H E Karnes
- Auditory and Vestibular Neuroscience Laboratory, Department of Otolaryngology-Head and Neck Surgery, University of Kansas Medical Center, Mail Stop 3051, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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41
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Afferent deprivation elicits a transcriptional response associated with neuronal survival after a critical period in the mouse cochlear nucleus. J Neurosci 2008; 28:10990-1002. [PMID: 18945907 DOI: 10.1523/jneurosci.2697-08.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The mechanisms underlying enhanced plasticity of synaptic connections and susceptibilities to manipulations of afferent activity in developing sensory systems are not well understood. One example is the rapid and dramatic neuron death that occurs after removal of afferent input to the cochlear nucleus (CN) of young mammals and birds. The molecular basis of this critical period of neuronal vulnerability and the transition to survival independent of afferent input remains to be defined. Here we used microarray analyses, real-time reverse transcription PCR, and immunohistochemistry of the mouse CN to show that deafferentation results in strikingly different sets of regulated genes in vulnerable [postnatal day (P)7] and invulnerable (P21) CN. An unexpectedly large set of immune-related genes was induced by afferent deprivation after the critical period, which corresponded with glial proliferation over the same time frame. Apoptotic gene expression was not highly regulated in the vulnerable CN after afferent deprivation but, surprisingly, did increase after deafferentation at P21, when all neurons ultimately survive. Pharmacological activity blockade in the eighth nerve mimicked afferent deprivation for only a subset of the afferent deprivation regulated genes, indicating the presence of an additional factor not dependent on action potential-mediated signaling that is also responsible for transcriptional changes. Overall, our results suggest that the cell death machinery during this critical period is mainly constitutive, whereas after the critical period neuronal survival could be actively promoted by both constitutive and induced gene expression.
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Bibliography. Current world literature. Atherosclerosis: cell biology and lipoproteins. Curr Opin Lipidol 2008; 19:525-35. [PMID: 18769235 DOI: 10.1097/mol.0b013e328312bffc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The nervous system contains a multitude of cell types which are specified during development by cascades of transcription factors acting combinatorially. Some of these transcription factors are only active during development, whereas others continue to function in the mature nervous system to maintain appropriate gene-expression patterns in differentiated cells. Underpinning the function of the nervous system is its plasticity in response to external stimuli, and many transcription factors are involved in regulating gene expression in response to neuronal activity, allowing us to learn, remember and make complex decisions. Here we review some of the recent findings that have uncovered the molecular mechanisms that underpin the control of gene regulatory networks within the nervous system. We highlight some recent insights into the gene-regulatory circuits in the development and differentiation of cells within the nervous system and discuss some of the mechanisms by which synaptic transmission influences transcription-factor activity in the mature nervous system. Mutations in genes that are important in epigenetic regulation (by influencing DNA methylation and post-translational histone modifications) have long been associated with neuronal disorders in humans such as Rett syndrome, Huntington's disease and some forms of mental retardation, and recent work has focused on unravelling their mechanisms of action. Finally, the discovery of microRNAs has produced a paradigm shift in gene expression, and we provide some examples and discuss the contribution of microRNAs to maintaining dynamic gene regulatory networks in the brain.
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