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Choudhry H, Aggarwal M, Pan PY. Mini-review: Synaptojanin 1 and its implications in membrane trafficking. Neurosci Lett 2021; 765:136288. [PMID: 34637856 PMCID: PMC8572151 DOI: 10.1016/j.neulet.2021.136288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 12/04/2022]
Abstract
This mini-review aims to summarize a growing body of literature on synaptojanin 1 (Synj1), a phosphoinositide phosphatase that was initially known to have a prominent role in synaptic vesicle recycling. Synj1 is coded by the SYNJ1 gene, whose mutations and variants are associated with an increasing number of neurological disorders. To better understand the mechanistic role of Synj1 in disease pathogenesis, we review details of phosphoinositide signaling pathways and the reported involvement of Synj1 in membrane trafficking with a specific focus on Parkinson’s disease (PD). Recent studies have tremendously advanced our understanding of Synj1 protein structure and function while broadening our view of how Synj1 regulates synaptic membrane trafficking and endosomal trafficking in various organisms and cell types. A growing body of evidence points to inefficient membrane trafficking as key pathogenic mechanisms in neurodegenerative diseases associated with abnormal Synj1 expression. Despite significant progress made in the field, the mechanism by which Synj1 connects to trafficking, signaling, and pathogenesis is lacking and remains to be addressed.
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Affiliation(s)
- Hassaam Choudhry
- Dept. of Neuroscience and Cell Biology, Rutgers, Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Meha Aggarwal
- Dept. of Neuroscience and Cell Biology, Rutgers, Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Ping-Yue Pan
- Dept. of Neuroscience and Cell Biology, Rutgers, Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA.
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2
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Pan PY, Zhu J, Rizvi A, Zhu X, Tanaka H, Dreyfus CF. Synaptojanin1 deficiency upregulates basal autophagosome formation in astrocytes. J Biol Chem 2021; 297:100873. [PMID: 34126070 PMCID: PMC8258991 DOI: 10.1016/j.jbc.2021.100873] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/02/2021] [Accepted: 06/10/2021] [Indexed: 01/07/2023] Open
Abstract
Macroautophagy dysregulation is implicated in multiple neurological disorders, such as Parkinson's disease. While autophagy pathways are heavily researched in heterologous cells and neurons, regulation of autophagy in the astrocyte, the most abundant cell type in the mammalian brain, is less well understood. Missense mutations in the Synj1 gene encoding Synaptojanin1 (Synj1), a neuron-enriched lipid phosphatase, have been linked to Parkinsonism with seizures. Our previous study showed that the Synj1 haploinsufficient (Synj1+/−) mouse exhibits age-dependent autophagy impairment in multiple brain regions. Here, we used cultured astrocytes from Synj1-deficient mice to investigate its role in astrocyte autophagy. We report that Synj1 is expressed in low levels in astrocytes and represses basal autophagosome formation. We demonstrate using cellular imaging that Synj1-deficient astrocytes exhibit hyperactive autophagosome formation, represented by an increase in the size and number of GFP-microtubule-associated protein 1A/1B-light chain 3 structures. Interestingly, Synj1 deficiency is also associated with an impairment in stress-induced autophagy clearance. We show, for the first time, that the Parkinsonism-associated R839C mutation impacts autophagy in astrocytes. The impact of this mutation on the phosphatase function of Synj1 resulted in elevated basal autophagosome formation that mimics Synj1 deletion. We found that the membrane expression of the astrocyte-specific glucose transporter GluT-1 was reduced in Synj1-deficient astrocytes. Consistently, AMP-activated protein kinase activity was elevated, suggesting altered glucose sensing in Synj1-deficient astrocytes. Expressing exogenous GluT-1 in Synj1-deficient astrocytes reversed the autophagy impairment, supporting a role for Synj1 in regulating astrocyte autophagy via disrupting glucose-sensing pathways. Thus, our work suggests a novel mechanism for Synj1-related Parkinsonism involving astrocyte dysfunction.
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Affiliation(s)
- Ping-Yue Pan
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.
| | - Justin Zhu
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Asma Rizvi
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Xinyu Zhu
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Hikari Tanaka
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Cheryl F Dreyfus
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
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3
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Casingal CR, Kikkawa T, Inada H, Sasaki Y, Osumi N. Identification of FMRP target mRNAs in the developmental brain: FMRP might coordinate Ras/MAPK, Wnt/β-catenin, and mTOR signaling during corticogenesis. Mol Brain 2020; 13:167. [PMID: 33323119 PMCID: PMC7739466 DOI: 10.1186/s13041-020-00706-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/23/2020] [Indexed: 01/18/2023] Open
Abstract
Corticogenesis is one of the most critical and complicated processes during embryonic brain development. Any slight impairment in corticogenesis could cause neurodevelopmental disorders such as Fragile X syndrome (FXS), of which symptoms contain intellectual disability (ID) and autism spectrum disorder (ASD). Fragile X mental retardation protein (FMRP), an RNA-binding protein responsible for FXS, shows strong expression in neural stem/precursor cells (NPCs) during corticogenesis, although its function during brain development remains largely unknown. In this study, we attempted to identify the FMRP target mRNAs in the cortical primordium using RNA immunoprecipitation sequencing analysis in the mouse embryonic brain. We identified 865 candidate genes as targets of FMRP involving 126 and 118 genes overlapped with ID and ASD-associated genes, respectively. These overlapped genes were enriched with those related to chromatin/chromosome organization and histone modifications, suggesting the involvement of FMRP in epigenetic regulation. We further identified a common set of 17 FMRP “core” target genes involved in neurogenesis/FXS/ID/ASD, containing factors associated with Ras/mitogen-activated protein kinase, Wnt/β-catenin, and mammalian target of rapamycin (mTOR) pathways. We indeed showed overactivation of mTOR signaling via an increase in mTOR phosphorylation in the Fmr1 knockout (Fmr1 KO) neocortex. Our results provide further insight into the critical roles of FMRP in the developing brain, where dysfunction of FMRP may influence the regulation of its mRNA targets affecting signaling pathways and epigenetic modifications.
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Affiliation(s)
- Cristine R Casingal
- Department of Developmental Neuroscience, United Center for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Takako Kikkawa
- Department of Developmental Neuroscience, United Center for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Hitoshi Inada
- Department of Developmental Neuroscience, United Center for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.,Laboratory of Health and Sports Sciences, Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, 6-6-12, Aramaki Aza Aoba Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Yukio Sasaki
- Functional Structure Biology Laboratory, Department of Medical Life Science, Yokohama City University Graduate School of Medical Life Science, 1-7-29 Suehiro-cho, Tsumuri-ku, Yokohama, 230-0045, Japan
| | - Noriko Osumi
- Department of Developmental Neuroscience, United Center for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
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4
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New tools for the visualization of glial fibrillary acidic protein in living cells. EXPERIMENTAL RESULTS 2020. [DOI: 10.1017/exp.2020.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractThe glial fibrillary acidic protein (GFAP) is an intermediate filament widely used to identify and label astroglial cells, a very abundant and relevant glial cell type in the central nervous system. A major hurdle in studying its behavior and function arises from the fact that GFAP does not tolerate well the addition of protein tags to its termini. Here, we tagged human GFAP (hGFAP) with an enhanced green fluorescent protein (EGFP) for the first time, and substituted a previously reported EGFP tag on mouse GFAP (mGFAP) by a more versatile Halo Tag. Both versions of tagged GFAP were able to incorporate into the normal GFAP filamentous network in glioma cells, and Alexander disease-related mutations or pharmacological disruption of microtubules and actin filaments interfered with GFAP dynamics. These new tools could provide new fruitful venues for the study of GFAP oligomerization, aggregation and dynamics in living cells.
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5
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Head E, Powell DK, Schmitt FA. Metabolic and Vascular Imaging Biomarkers in Down Syndrome Provide Unique Insights Into Brain Aging and Alzheimer Disease Pathogenesis. Front Aging Neurosci 2018; 10:191. [PMID: 29977201 PMCID: PMC6021507 DOI: 10.3389/fnagi.2018.00191] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/06/2018] [Indexed: 12/26/2022] Open
Abstract
People with Down syndrome (DS) are at high risk for developing Alzheimer disease (AD). Neuropathology consistent with AD is present by 40 years of age and dementia may develop up to a decade later. In this review, we describe metabolic and vascular neuroimaging studies in DS that suggest these functional changes are a key feature of aging, linked to cognitive decline and AD in this vulnerable cohort. FDG-PET imaging in DS suggests systematic reductions in glucose metabolism in posterior cingulate and parietotemporal cortex. Magentic resonance spectroscopy studies show consistent decreases in neuronal health and increased myoinositol, suggesting inflammation. There are few vascular imaging studies in DS suggesting a gap in our knowledge. Future studies would benefit from longitudinal measures and combining various imaging approaches to identify early signs of dementia in DS that may be amenable to intervention.
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Affiliation(s)
- Elizabeth Head
- Department of Pharmacology & Nutritional Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - David K Powell
- Magnetic Resonance Imaging and Spectroscopy Center, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Frederick A Schmitt
- Department of Neurology, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States
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Lin AL, Powell D, Caban-Holt A, Jicha G, Robertson W, Gold BT, Davis R, Abner E, Wilcock DM, Schmitt FA, Head E. (1)H-MRS metabolites in adults with Down syndrome: Effects of dementia. NEUROIMAGE-CLINICAL 2016; 11:728-735. [PMID: 27330972 PMCID: PMC4908308 DOI: 10.1016/j.nicl.2016.06.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 04/11/2016] [Accepted: 06/01/2016] [Indexed: 02/04/2023]
Abstract
To determine if proton magnetic resonance spectroscopy (1H-MRS) detect differences in dementia status in adults with Down syndrome (DS), we used 1H-MRS to measure neuronal and glial metabolites in the posterior cingulate cortex in 22 adults with DS and in 15 age- and gender-matched healthy controls. We evaluated associations between 1H-MRS results and cognition among DS participants. Neuronal biomarkers, including N-acetylaspartate (NAA) and glutamate-glutamine complex (Glx), were significantly lower in DS patients with Alzheimer's should probably be changed to Alzheimer (without ' or s) through ms as per the new naming standard disease (DSAD) when compared to non-demented DS (DS) and healthy controls (CTL). Neuronal biomarkers therefore appear to reflect dementia status in DS. In contrast, all DS participants had significantly higher myo-inositol (MI), a putative glial biomarker, compared to CTL. Our data indicate that there may be an overall higher glial inflammatory component in DS compared to CTL prior to and possibly independent of developing dementia. When computing the NAA to MI ratio, we found that presence or absence of dementia could be distinguished in DS. NAA, Glx, and NAA/MI in all DS participants were correlated with scores from the Brief Praxis Test and the Severe Impairment Battery. 1H-MRS may be a useful diagnostic tool in future longitudinal studies to measure AD progression in persons with DS. In particular, NAA and the NAA/MI ratio is sensitive to the functional status of adults with DS, including prior to dementia. 1H-MRS was used to compare demented and nondemented adults with Down syndrome. Neuronal biomarkers were lowest in demented adults with Down syndrome. Glial biomarkers including myoinositol were higher in demented adults with DS. Neuronal and glial biomarkers were correlated with cognition in Down syndrome.
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Affiliation(s)
- A-L Lin
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - D Powell
- Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY, USA; Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY, USA
| | - A Caban-Holt
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - G Jicha
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - W Robertson
- Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - B T Gold
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY, USA; Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY, USA
| | - R Davis
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - E Abner
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - D M Wilcock
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - F A Schmitt
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - E Head
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
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7
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Martin SB, Dowling ALS, Lianekhammy J, Lott IT, Doran E, Murphy MP, Beckett TL, Schmitt FA, Head E. Synaptophysin and synaptojanin-1 in Down syndrome are differentially affected by Alzheimer's disease. J Alzheimers Dis 2015; 42:767-75. [PMID: 24927707 DOI: 10.3233/jad-140795] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Adults with Down syndrome (DS) develop Alzheimer's disease (AD) neuropathology by 40 years of age. Synaptophysin (SYN) consistently declines with age and is further reduced with sporadic AD. Thus, we hypothesized that SYN would be reduced in DS with AD. The gene for synaptojanin-1 (SYNJ1), involved in synaptic vesicle recycling, is on chromosome 21. We measured SYN and SYNJ1 in an autopsy series of 39 cases with DS and 28 without DS, along with 7 sporadic AD cases. SYN was significantly lower in DSAD compared with DS alone and similar to sporadic AD. Reduced SYN is associated with AD neuropathology and with Aβ levels in DS, as is seen in sporadic AD. SYNJ1 was significantly higher in DS and correlated with several measures of Aβ. SYNJ1 was higher in DSAD and significantly higher than SYNJ1 in sporadic AD. Although significantly higher in DS, SYNJ1 is further increased with AD neuropathology suggesting interesting differences in a synapse-associated protein that is overexpressed in trisomy 21.
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Affiliation(s)
- Sarah B Martin
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Amy L S Dowling
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Joann Lianekhammy
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Ira T Lott
- Department of Physiology, University of Kentucky, Lexington, KY, USA Department of Pediatrics and Neurology, School of Medicine, University of California-Irvine (UCI), Orange, CA, USA
| | - Eric Doran
- Department of Physiology, University of Kentucky, Lexington, KY, USA Department of Pediatrics and Neurology, School of Medicine, University of California-Irvine (UCI), Orange, CA, USA
| | - M Paul Murphy
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA UK Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Tina L Beckett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Frederick A Schmitt
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - Elizabeth Head
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY, USA
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8
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Ueda Y. The Role of Phosphoinositides in Synapse Function. Mol Neurobiol 2014; 50:821-38. [DOI: 10.1007/s12035-014-8768-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 06/01/2014] [Indexed: 11/30/2022]
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Bando SY, Silva FN, Costa LDF, Silva AV, Pimentel-Silva LR, Castro LHM, Wen HT, Amaro E, Moreira-Filho CA. Complex network analysis of CA3 transcriptome reveals pathogenic and compensatory pathways in refractory temporal lobe epilepsy. PLoS One 2013; 8:e79913. [PMID: 24278214 PMCID: PMC3836787 DOI: 10.1371/journal.pone.0079913] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/25/2013] [Indexed: 12/21/2022] Open
Abstract
We previously described - studying transcriptional signatures of hippocampal CA3 explants - that febrile (FS) and afebrile (NFS) forms of refractory mesial temporal lobe epilepsy constitute two distinct genomic phenotypes. That network analysis was based on a limited number (hundreds) of differentially expressed genes (DE networks) among a large set of valid transcripts (close to two tens of thousands). Here we developed a methodology for complex network visualization (3D) and analysis that allows the categorization of network nodes according to distinct hierarchical levels of gene-gene connections (node degree) and of interconnection between node neighbors (concentric node degree). Hubs are highly connected nodes, VIPs have low node degree but connect only with hubs, and high-hubs have VIP status and high overall number of connections. Studying the whole set of CA3 valid transcripts we: i) obtained complete transcriptional networks (CO) for FS and NFS phenotypic groups; ii) examined how CO and DE networks are related; iii) characterized genomic and molecular mechanisms underlying FS and NFS phenotypes, identifying potential novel targets for therapeutic interventions. We found that: i) DE hubs and VIPs are evenly distributed inside the CO networks; ii) most DE hubs and VIPs are related to synaptic transmission and neuronal excitability whereas most CO hubs, VIPs and high hubs are related to neuronal differentiation, homeostasis and neuroprotection, indicating compensatory mechanisms. Complex network visualization and analysis is a useful tool for systems biology approaches to multifactorial diseases. Network centrality observed for hubs, VIPs and high hubs of CO networks, is consistent with the network disease model, where a group of nodes whose perturbation leads to a disease phenotype occupies a central position in the network. Conceivably, the chance for exerting therapeutic effects through the modulation of particular genes will be higher if these genes are highly interconnected in transcriptional networks.
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Affiliation(s)
- Silvia Yumi Bando
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil
| | | | | | - Alexandre V. Silva
- Department of Biosciences, Universidade Federal de São Paulo, Santos, São Paulo, Brazil
| | | | - Luiz HM. Castro
- Clinical Neurology Division, Hospital das Clínicas da FMUSP, São Paulo, São Paulo, Brazil
| | - Hung-Tzu Wen
- Epilepsy Surgery Group, Hospital das Clínicas da FMUSP, São Paulo, São Paulo, Brazil
| | - Edson Amaro
- Department of Radiology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil
| | - Carlos Alberto Moreira-Filho
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil
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10
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Molecular and cellular alterations in Down syndrome: toward the identification of targets for therapeutics. Neural Plast 2012; 2012:171639. [PMID: 22848846 PMCID: PMC3403492 DOI: 10.1155/2012/171639] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/18/2012] [Accepted: 04/19/2012] [Indexed: 12/25/2022] Open
Abstract
Down syndrome is a complex disease that has challenged molecular and cellular research for more than 50 years. Understanding the molecular bases of morphological, cellular, and functional alterations resulting from the presence of an additional complete chromosome 21 would aid in targeting specific genes and pathways for rescuing some phenotypes. Recently, progress has been made by characterization of brain alterations in mouse models of Down syndrome. This review will highlight the main molecular and cellular findings recently described for these models, particularly with respect to their relationship to Down syndrome phenotypes.
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11
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Herrera F, Maher P, Schubert D. c-Jun N-terminal kinase controls a negative loop in the regulation of glial fibrillary acidic protein expression by retinoic acid. Neuroscience 2012; 208:143-9. [PMID: 22387108 DOI: 10.1016/j.neuroscience.2012.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/31/2012] [Accepted: 02/08/2012] [Indexed: 11/26/2022]
Abstract
Glial fibrillary acidic protein (GFAP) is a protein widely used as a molecular marker for astroglial differentiation and mature astrocytes. We and others have shown previously that retinoic acid and specific cytokines induce the expression of GFAP in neural precursor cells by activating the phosphatidylinositol-4,5-bisphosphate-3-kinase (PI3K) phosphorylation pathway. Here, we extend our previous work and show that retinoic acid also activates specifically the c-Jun N-terminal kinase (JNK) phosphorylation pathway, which in turn inhibits GFAP expression. Our results suggest the existence of a negative self-regulatory loop in the phosphorylation pathways that regulates GFAP expression. This loop is constitutively repressed by the PI3K pathway. Our results could be relevant for disorders involving sustained GFAP overexpression in precursor cells, such as glioblastoma and Alexander disease.
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Affiliation(s)
- F Herrera
- Cellular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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12
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Wen PJ, Osborne SL, Meunier FA. Phosphoinositides in neuroexocytosis and neuronal diseases. Curr Top Microbiol Immunol 2012; 362:87-98. [PMID: 23086414 DOI: 10.1007/978-94-007-5025-8_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Phosphoinositides (PIs) are a family of phospholipids derived from phosphatidylinositol (PtdIns), whose location, synthesis, and degradation depend on specific PI kinases and phosphatases. PIs have emerged as fundamental regulators of secretory processes, such as neurotransmitter release, hormone secretion, and histamine release in allergic responses. In neurons and neuroendocrine cells, regulated secretion requires the calcium-dependent fusion of transmitter-containing vesicles with the plasma membrane. The role played by PIs in exocytosis is best exemplified by the Ca²⁺-dependent binding of vesicular Synaptotagmin1 to the plasma membrane PtdIns(4,5)P₂, and the recently demonstrated role of PtdIns(4,5)P₂ in the mobilization of secretory vesicles to the plasma membrane. New evidence has also recently emerged of an alternative PI pathway that can control exocytosis positively (via PtdIn3P) or negatively (via PtdIns(3,5)P₂). However, the positive or negative effectors for these pathways remain to be established. Reducing PtdIns(3,5)P₂ potentiates neuroexocytosis but leads to neuronal degeneration and has been linked to certain forms of Charcot-Marie-Tooth disease and amyotrophic lateral sclerosis. The goal of this review is to describe the role of PIs in neuroexocytosis and explore the current hypotheses linking these effects to human diseases.
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Affiliation(s)
- Peter J Wen
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Australia
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13
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Herrera F, Outeiro TF. α-Synuclein modifies huntingtin aggregation in living cells. FEBS Lett 2011; 586:7-12. [PMID: 22119730 DOI: 10.1016/j.febslet.2011.11.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 11/10/2011] [Indexed: 11/15/2022]
Abstract
Several neurodegenerative disorders are characterized by the accumulation of proteinaceous inclusions in the central nervous system. These inclusions are frequently composed of a mixture of aggregation-prone proteins. Here, we used a bimolecular fluorescence complementation assay to study the initial steps of the co-aggregation of huntingtin (Htt) and α-synuclein (α-syn), two aggregation-prone proteins involved in Huntington's disease (HD) and Parkinson's disease (PD), respectively. We found that Htt (exon 1) oligomerized with α-syn and sequestered it in the cytosol. In turn, α-syn increased the number of cells displaying aggregates, decreased the number of aggregates per cell and increased the average size of the aggregates. Our results support the idea that co-aggregation of aggregation-prone proteins can contribute to the histopathology of neurodegenerative disorders.
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Affiliation(s)
- Federico Herrera
- Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular, Lisboa, Portugal
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14
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Keck-Wherley J, Grover D, Bhattacharyya S, Xu X, Holman D, Lombardini ED, Verma R, Biswas R, Galdzicki Z. Abnormal microRNA expression in Ts65Dn hippocampus and whole blood: contributions to Down syndrome phenotypes. Dev Neurosci 2011; 33:451-67. [PMID: 22042248 PMCID: PMC3254042 DOI: 10.1159/000330884] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 07/06/2011] [Indexed: 12/22/2022] Open
Abstract
Down syndrome (DS; trisomy 21) is one of the most common genetic causes of intellectual disability, which is attributed to triplication of genes located on chromosome 21. Elevated levels of several microRNAs (miRNAs) located on chromosome 21 have been reported in human DS heart and brain tissues. The Ts65Dn mouse model is the most investigated DS model with a triplicated segment of mouse chromosome 16 harboring genes orthologous to those on human chromosome 21. Using ABI TaqMan miRNA arrays, we found a set of miRNAs that were significantly up- or downregulated in the Ts65Dn hippocampus compared to euploid controls. Furthermore, miR-155 and miR-802 showed significant overexpression in the Ts65Dn hippocampus, thereby confirming results of previous studies. Interestingly, miR-155 and miR-802 were also overexpressed in the Ts65Dn whole blood but not in lung tissue. We also found overexpression of the miR-155 precursors, pri- and pre-miR-155 derived from the miR-155 host gene, known as B cell integration cluster, suggesting enhanced biogenesis of miR-155. Bioinformatic analysis revealed that neurodevelopment, differentiation of neuroglia, apoptosis, cell cycle, and signaling pathways including ERK/MAPK, protein kinase C, phosphatidylinositol 3-kinase, m-TOR and calcium signaling are likely targets of these miRNAs. We selected some of these potential gene targets and found downregulation of mRNA encoding Ship1, Mecp2 and Ezh2 in Ts65Dn hippocampus. Interestingly, the miR-155 target gene Ship1 (inositol phosphatase) was also downregulated in Ts65Dn whole blood but not in lung tissue. Our findings provide insights into miRNA-mediated gene regulation in Ts65Dn mice and their potential contribution to impaired hippocampal synaptic plasticity and neurogenesis, as well as hemopoietic abnormalities observed in DS.
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Affiliation(s)
- Jennifer Keck-Wherley
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
- Department of Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Deepak Grover
- Department of Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Sharmistha Bhattacharyya
- Department of Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Xiufen Xu
- Department of Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Derek Holman
- Department of Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Eric D. Lombardini
- Department of Comparative Pathology Division, Veterinary Sciences Department, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Ranjana Verma
- Department of Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Roopa Biswas
- Department of Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md., USA
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15
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Chiron S, Wei Z, Chen Y, Zhang K, Wen G, Fischer WH, Mahata SK, O'Connor DT. Proteomic analysis yields an unexpected trans-acting point in control of the human sympathochromaffin phenotype. ACTA ACUST UNITED AC 2011; 4:437-45. [PMID: 21551321 DOI: 10.1161/circgenetics.110.957886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND The secretory protein chromogranin A (CHGA) plays a necessary role in formation of catecholamine storage vesicles and gives rise to a catecholamine release-inhibitory fragment. Because genetic variation in the proximal human CHGA promoter predicts autonomic function and blood pressure, we explored how a common genetic variant alters transcription of the gene. METHODS AND RESULTS Bioinformatic analysis suggested that the common G-462A promoter variant (rs9658634) may disrupt as many as 3 transcriptional control motifs: LEF1, COUP-TF, and PPARγ-RXRα. During electrophoretic mobility shifts, chromaffin cell nuclear proteins bound specifically to the A (though not G) allele of CHGA promoter G-462A. On oligonucleotide affinity chromatography followed by electrospray ionization followed by 2-dimensional (tandem) mass spectrometry analysis of A allele eluates, the transcription factor LEF1 (lymphoid enhancer-binding factor-1) was identified. Interaction of LEF1 with the A allele at G-462A was confirmed by supershift. On cotransfection, LEF1 discriminated between the allelic variants, especially in chromaffin cells. Allele specificity of trans-activation by LEF1 was transferable to an isolated G-462A element fused to a heterologous (SV40) promoter. Because β-catenin (CTNNB1) can heterodimerize with LEF1, we tested the effect of cotransfection of this factor and again found A allele-specific perturbation of CHGA transcription. CONCLUSIONS Common genetic variation within the human CHGA promoter alters the interaction of specific factors in trans with the promoter, with LEF1 identified by proteomic analysis and confirmed by supershift. Coexpression experiments show functional effects of LEF1 and CTNNB1 on CHGA promoter. The findings document a novel role for components of the immune and WNT pathways in control of human sympathochromaffin phenotypes.
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Affiliation(s)
- Stéphane Chiron
- Department of Medicine and Institute for Genomic Medicine, University of California at San Diego, La Jolla, 92093–0838, USA
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16
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Macfarlan TS, Gifford WD, Agarwal S, Driscoll S, Lettieri K, Wang J, Andrews SE, Franco L, Rosenfeld MG, Ren B, Pfaff SL. Endogenous retroviruses and neighboring genes are coordinately repressed by LSD1/KDM1A. Genes Dev 2011; 25:594-607. [PMID: 21357675 DOI: 10.1101/gad.2008511] [Citation(s) in RCA: 186] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Endogenous retroviruses (ERVs) constitute a substantial portion of mammalian genomes, and their retrotransposition activity helped to drive genetic variation, yet their expression is tightly regulated to prevent unchecked amplification. We generated a series of mouse mutants and embryonic stem (ES) cell lines carrying "deletable" and "rescuable" alleles of the lysine-specific demethylase LSD1/KDM1A. In the absence of KDM1A, the murine endogenous retrovirus MuERV-L/MERVL becomes overexpressed and embryonic development arrests at gastrulation. A number of cellular genes normally restricted to the zygotic genome activation (ZGA) period also become up-regulated in Kdm1a mutants. Strikingly, many of these cellular genes are flanked by MERVL sequences or have cryptic LTRs as promoters that are targets of KDM1A repression. Using genome-wide epigenetic profiling of Kdm1a mutant ES cells, we demonstrate that this subset of ZGA genes and MERVL elements displays increased methylation of histone H3K4, increased acetylation of H3K27, and decreased methylation of H3K9. As a consequence, Kdm1a mutant ES cells exhibit an unusual propensity to generate extraembryonic tissues. Our findings suggest that ancient retroviral insertions were used to co-opt regulatory sequences targeted by KDM1A for epigenetic silencing of cell fate genes during early mammalian embryonic development.
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Affiliation(s)
- Todd S Macfarlan
- Gene Expression Laboratory, Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California, 92037, USA
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17
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Wen P, Osborne S, Meunier F. Dynamic control of neuroexocytosis by phosphoinositides in health and disease. Prog Lipid Res 2011; 50:52-61. [DOI: 10.1016/j.plipres.2010.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/02/2010] [Indexed: 10/19/2022]
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18
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Herrera F, Chen Q, Schubert D. Synergistic effect of retinoic acid and cytokines on the regulation of glial fibrillary acidic protein expression. J Biol Chem 2010; 285:38915-22. [PMID: 20876578 DOI: 10.1074/jbc.m110.170274] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glial fibrillary acidic protein (GFAP) is the main astroglial marker during astrogliogenesis, but it is also expressed in other cell types, including neural stem cells and old neurons. Activation of the JAK/STAT pathway by the IL-6 family of cytokines is the canonical pathway regulating GFAP expression, whereas retinoic acid is thought to be the only inducer of GFAP to operate independently of this pathway. Here, we show that retinoic acid receptor α not only links retinoic acid signaling to the canonical cytokine-stimulated pathway leading to GFAP expression but that it also plays a key role in the synergistic actions of retinoic acid and cytokines on this pathway. Cytokines both potentiate retinoic acid receptor α expression and enhance its binding to DNA and to the Stat3-p300/CBP-Smad transcriptional complex, the cornerstone of the canonical pathway. PI3K is upstream to all the key events leading to the expression of GFAP. Our results give new insights about the role of retinoic acid signaling in GFAP expression.
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Affiliation(s)
- Federico Herrera
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
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19
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Sorci G, Bianchi R, Riuzzi F, Tubaro C, Arcuri C, Giambanco I, Donato R. S100B Protein, A Damage-Associated Molecular Pattern Protein in the Brain and Heart, and Beyond. Cardiovasc Psychiatry Neurol 2010; 2010:656481. [PMID: 20827421 PMCID: PMC2933911 DOI: 10.1155/2010/656481] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 06/08/2010] [Indexed: 12/15/2022] Open
Abstract
S100B belongs to a multigenic family of Ca(2+)-binding proteins of the EF-hand type and is expressed in high abundance in the brain. S100B interacts with target proteins within cells thereby altering their functions once secreted/released with the multiligand receptor RAGE. As an intracellular regulator, S100B affects protein phosphorylation, energy metabolism, the dynamics of cytoskeleton constituents (and hence, of cell shape and migration), Ca(2+) homeostasis, and cell proliferation and differentiation. As an extracellular signal, at low, physiological concentrations, S100B protects neurons against apoptosis, stimulates neurite outgrowth and astrocyte proliferation, and negatively regulates astrocytic and microglial responses to neurotoxic agents, while at high doses S100B causes neuronal death and exhibits properties of a damage-associated molecular pattern protein. S100B also exerts effects outside the brain; as an intracellular regulator, S100B inhibits the postinfarction hypertrophic response in cardiomyocytes, while as an extracellular signal, (high) S100B causes cardiomyocyte death, activates endothelial cells, and stimulates vascular smooth muscle cell proliferation.
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Affiliation(s)
- Guglielmo Sorci
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Roberta Bianchi
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Francesca Riuzzi
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Claudia Tubaro
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Cataldo Arcuri
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Ileana Giambanco
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Rosario Donato
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
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20
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Zhou X, Chen Q, Schaukowitch K, Kelsoe JR, Geyer MA. Insoluble DISC1-Boymaw fusion proteins generated by DISC1 translocation. Mol Psychiatry 2010; 15:669-72. [PMID: 20351725 PMCID: PMC2891102 DOI: 10.1038/mp.2009.127] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Xianjin Zhou
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093,To whom correspondence should be addressed ()
| | - Qi Chen
- Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037
| | - Katie Schaukowitch
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093
| | - John R Kelsoe
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093
| | - Mark A Geyer
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093
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