451
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Hernandez MX, Jiang S, Cole TA, Chu SH, Fonseca MI, Fang MJ, Hohsfield LA, Torres MD, Green KN, Wetsel RA, Mortazavi A, Tenner AJ. Prevention of C5aR1 signaling delays microglial inflammatory polarization, favors clearance pathways and suppresses cognitive loss. Mol Neurodegener 2017; 12:66. [PMID: 28923083 PMCID: PMC5604420 DOI: 10.1186/s13024-017-0210-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/12/2017] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Pharmacologic inhibition of C5aR1, a receptor for the complement activation proinflammatory fragment, C5a, suppressed pathology and cognitive deficits in Alzheimer's disease (AD) mouse models. To validate that the effect of the antagonist was specifically via C5aR1 inhibition, mice lacking C5aR1 were generated and compared in behavior and pathology. In addition, since C5aR1 is primarily expressed on cells of the myeloid lineage, and only to a lesser extent on endothelial cells and neurons in brain, gene expression in microglia isolated from adult brain at multiple ages was compared across all genotypes. METHODS C5aR1 knock out mice were crossed to the Arctic AD mouse model, and characterized for pathology and for behavior performance in a hippocampal dependent memory task. CX3CR1GFP and CCR2RFP reporter mice were bred to C5aR1 sufficient and knockout wild type and Arctic mice to enable sorting of microglia (GFP-positive, RFP-negative) isolated from adult brain at 2, 5, 7 and 10 months of age followed by RNA-seq analysis. RESULTS A lack of C5aR1 prevented behavior deficits at 10 months, although amyloid plaque load was not altered. Immunohistochemical analysis showed no CCR2+ monocytes/macrophages near the plaques in the Arctic brain with or without C5aR1. Microglia were sorted from infiltrating monocytes (GFP and RFP-positive) for transcriptome analysis. RNA-seq analysis identified inflammation related genes as differentially expressed, with increased expression in the Arctic mice relative to wild type and decreased expression in the Arctic/C5aR1KO relative to Arctic. In addition, phagosomal-lysosomal gene expression was increased in the Arctic mice relative to wild type but further increased in the Arctic/C5aR1KO mice. A decrease in neuronal complexity was seen in hippocampus of 10 month old Arctic mice at the time that correlates with the behavior deficit, both of which were rescued in the Arctic/C5aR1KO. CONCLUSIONS These data are consistent with microglial polarization in the absence of C5aR1 signaling reflecting decreased induction of inflammatory genes and enhancement of degradation/clearance pathways, which is accompanied by preservation of CA1 neuronal complexity and hippocampal dependent cognitive function. These results provide links between microglial responses and loss of cognitive performance and, combined with the previous pharmacological approach to inhibit C5aR1 signaling, support the potential of this receptor as a novel therapeutic target for AD in humans.
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Affiliation(s)
- Michael X Hernandez
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California, Irvine, CA, USA
| | - Shan Jiang
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Tracy A Cole
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
- Present Address: Ionis Pharmaceuticals Inc., Carlsbad, CA, 92010, USA
| | - Shu-Hui Chu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA
| | - Maria I Fonseca
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA
| | - Melody J Fang
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA
| | - Lindsay A Hohsfield
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - Maria D Torres
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - Rick A Wetsel
- Research Center for Immunology and Autoimmune Diseases, Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas-Houston, Houston, TX, USA
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Andrea J Tenner
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California, Irvine, CA, USA.
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA.
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA.
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452
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Gao FB, Almeida S, Lopez-Gonzalez R. Dysregulated molecular pathways in amyotrophic lateral sclerosis-frontotemporal dementia spectrum disorder. EMBO J 2017; 36:2931-2950. [PMID: 28916614 DOI: 10.15252/embj.201797568] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/15/2017] [Accepted: 08/30/2017] [Indexed: 12/11/2022] Open
Abstract
Frontotemporal dementia (FTD), the second most common form of dementia in people under 65 years of age, is characterized by progressive atrophy of the frontal and/or temporal lobes. FTD overlaps extensively with the motor neuron disease amyotrophic lateral sclerosis (ALS), especially at the genetic level. Both FTD and ALS can be caused by many mutations in the same set of genes; the most prevalent of these mutations is a GGGGCC repeat expansion in the first intron of C9ORF72 As shown by recent intensive studies, some key cellular pathways are dysregulated in the ALS-FTD spectrum disorder, including autophagy, nucleocytoplasmic transport, DNA damage repair, pre-mRNA splicing, stress granule dynamics, and others. These exciting advances reveal the complexity of the pathogenic mechanisms of FTD and ALS and suggest promising molecular targets for future therapeutic interventions in these devastating disorders.
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Affiliation(s)
- Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
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453
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Loss of TMEM106B Ameliorates Lysosomal and Frontotemporal Dementia-Related Phenotypes in Progranulin-Deficient Mice. Neuron 2017; 95:281-296.e6. [PMID: 28728022 DOI: 10.1016/j.neuron.2017.06.026] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 03/23/2017] [Accepted: 06/15/2017] [Indexed: 12/13/2022]
Abstract
Progranulin (GRN) and TMEM106B are associated with several common neurodegenerative disorders including frontotemporal lobar degeneration (FTLD). A TMEM106B variant modifies GRN-associated FTLD risk. However, their functional relationship in vivo and the mechanisms underlying the risk modification remain unclear. Here, using transcriptomic and proteomic analyses with Grn-/- and Tmem106b-/- mice, we show that, while multiple lysosomal enzymes are increased in Grn-/- brain at both transcriptional and protein levels, TMEM106B deficiency causes reduction in several lysosomal enzymes. Remarkably, Tmem106b deletion from Grn-/- mice normalizes lysosomal protein levels and rescues FTLD-related behavioral abnormalities and retinal degeneration without improving lipofuscin, C1q, and microglial accumulation. Mechanistically, TMEM106B binds vacuolar-ATPase accessory protein 1 (AP1). TMEM106B deficiency reduces vacuolar-ATPase AP1 and V0 subunits, impairing lysosomal acidification and normalizing lysosomal protein levels in Grn-/- neurons. Thus, Grn and Tmem106b genes have opposite effects on lysosomal enzyme levels, and their interaction determines the extent of neurodegeneration.
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454
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Longhena F, Zaltieri M, Grigoletto J, Faustini G, La Via L, Ghidoni R, Benussi L, Missale C, Spano P, Bellucci A. Depletion of Progranulin Reduces GluN2B-Containing NMDA Receptor Density, Tau Phosphorylation, and Dendritic Arborization in Mouse Primary Cortical Neurons. J Pharmacol Exp Ther 2017; 363:164-175. [DOI: 10.1124/jpet.117.242164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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455
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Wauters E, Van Mossevelde S, Van der Zee J, Cruts M, Van Broeckhoven C. Modifiers of GRN-Associated Frontotemporal Lobar Degeneration. Trends Mol Med 2017; 23:962-979. [PMID: 28890134 DOI: 10.1016/j.molmed.2017.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/12/2017] [Accepted: 08/15/2017] [Indexed: 12/13/2022]
Abstract
Heterozygous loss-of-function (LOF) mutations in the human progranulin gene (GRN) cause frontotemporal lobar degeneration (FTLD) by a mechanism of haploinsufficiency. Patients present most frequently with frontotemporal dementia, which is the second most common neurodegenerative dementia at young age. Currently, no disease-modifying therapies are available for these patients. Stimulating GRN protein expression or inhibiting its breakdown is an obvious therapeutic strategy, and is indeed the focus of current preclinical research and clinical trials. Multiple studies have demonstrated the heterogeneity in clinical presentation and wide variability in age of onset in patients carrying a GRN LOF mutation. Recently, this heterogeneity became an opportunity to identify disease modifiers, considering that these might constitute suitable targets for developing disease-modifying or disease-delaying therapies.
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Affiliation(s)
- Eline Wauters
- Neurodegenerative Brain Diseases, Center for Molecular Neurology, VIB, Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Sara Van Mossevelde
- Neurodegenerative Brain Diseases, Center for Molecular Neurology, VIB, Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium; Department of Neurology and Memory Clinic, Hospital Network Antwerp Middelheim and Hoge Beuken, Antwerp, Belgium; Department of Neurology, Antwerp University Hospital, Edegem, Belgium
| | - Julie Van der Zee
- Neurodegenerative Brain Diseases, Center for Molecular Neurology, VIB, Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Marc Cruts
- Neurodegenerative Brain Diseases, Center for Molecular Neurology, VIB, Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Christine Van Broeckhoven
- Neurodegenerative Brain Diseases, Center for Molecular Neurology, VIB, Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.
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456
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Hosokawa M, Tanaka Y, Arai T, Kondo H, Akiyama H, Hasegawa M. Progranulin haploinsufficiency reduces amyloid beta deposition in Alzheimer's disease model mice. Exp Anim 2017; 67:63-70. [PMID: 28845019 PMCID: PMC5814315 DOI: 10.1538/expanim.17-0060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Granulin (Grn) mutations were identified in familial frontotemporal
lobar degeneration (FTLD) patients with TAR DNA-binding protein of 43 kd (TDP-43)
pathology. Grn transcript haploinsufficiency is proposed as a disease
mechanism that leads to the loss of functional progranulin (PGRN) protein. Thus, these
mutations are strongly involved in FTLD pathogenesis. Moreover, recent findings indicate
that Grn mutations are associated with other neurodegenerative disorders
with tau pathology, including Alzheimer’s disease. To investigate the influence of PGRN on
amyloid beta (Aβ) accumulation, amyloid precursor protein (APP) transgenic mice were
interbred with Grn-deficient mice, producing APP transgenic mice
harboring the Grn hemizygote (APP/Grn+/−).
Brains were collected from 16–18-month-old APP and APP/Grn+/−
mice and sequential extraction of proteins, immunoblotting and immunohistochemical
analysis were performed. Immunohistochemical analysis showed that the number and area of
Aβ plaque was significantly decreased in APP/Grn+/− mice as
compared to APP mice. Immunoblotting analysis revealed that Aβ was reduced in the
sarkosyl-insoluble fraction of 16–18-month-old APP/Grn+/− mice
as compared with that of APP transgenic mice. Our data suggest that PGRN
haploinsufficiency may decrease accumulation of Aβ.
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Affiliation(s)
- Masato Hosokawa
- Dementia research project, Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Yoshinori Tanaka
- Dementia research project, Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Tetsuaki Arai
- Dementia research project, Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.,Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8576 Japan
| | - Hiromi Kondo
- Histology center, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Haruhiko Akiyama
- Dementia research project, Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Masato Hasegawa
- Dementia research project, Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
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457
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Whitelaw BS. Microglia-mediated synaptic elimination in neuronal development and disease. J Neurophysiol 2017; 119:1-4. [PMID: 28835520 DOI: 10.1152/jn.00021.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It has recently become clear that microglia, the immune cells of the central nervous system, are far more active in the healthy brain than previously thought. Microglia facilitate many stages of brain development by shaping neuronal connectivity via synaptic elimination. Dysfunction of these same processes likely underlies a wide range of neurological and neurodevelopmental disorders.
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Affiliation(s)
- Brendan S Whitelaw
- School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, New York
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458
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Araújo SES, Mendonça HR, Wheeler NA, Campello-Costa P, Jacobs KM, Gomes FCA, Fox MA, Fuss B. Inflammatory demyelination alters subcortical visual circuits. J Neuroinflammation 2017; 14:162. [PMID: 28821276 PMCID: PMC5562979 DOI: 10.1186/s12974-017-0936-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/07/2017] [Indexed: 11/13/2022] Open
Abstract
Background Multiple sclerosis (MS) is an inflammatory demyelinating disease classically associated with axonal damage and loss; more recently, however, synaptic changes have been recognized as additional contributing factors. An anatomical area commonly affected in MS is the visual pathway; yet, changes other than those associated with inflammatory demyelination of the optic nerve, i.e., optic neuritis, have not been described in detail. Methods Adult mice were subjected to a diet containing cuprizone to mimic certain aspects of inflammatory demyelination as seen in MS. Demyelination and inflammation were assessed by real-time polymerase chain reaction and immunohistochemistry. Synaptic changes associated with inflammatory demyelination in the dorsal lateral geniculate nucleus (dLGN) were determined by immunohistochemistry, Western blot analysis, and electrophysiological field potential recordings. Results In the cuprizone model, demyelination was observed in retinorecipient regions of the subcortical visual system, in particular the dLGN, where it was found accompanied by microglia activation and astrogliosis. In contrast, anterior parts of the pathway, i.e., the optic nerve and tract, appeared largely unaffected. Under the inflammatory demyelinating conditions, as seen in the dLGN of cuprizone-treated mice, there was an overall decrease in excitatory synaptic inputs from retinal ganglion cells. At the same time, the number of synaptic complexes arising from gamma-aminobutyric acid (GABA)-generating inhibitory neurons was found increased, as were the synapses that contain the N-methyl-d-aspartate receptor (NMDAR) subunit GluN2B and converge onto inhibitory neurons. These synaptic changes were functionally found associated with a shift toward an overall increase in network inhibition. Conclusions Using the cuprizone model of inflammatory demyelination, our data reveal a novel form of synaptic (mal)adaption in the CNS that is characterized by a shift of the excitation/inhibition balance toward inhibitory network activity associated with an increase in GABAergic inhibitory synapses and a possible increase in excitatory input onto inhibitory interneurons. In addition, our data recognize the cuprizone model as a suitable tool in which to assess the effects of inflammatory demyelination on subcortical retinorecipient regions of the visual system, such as the dLGN, in the absence of overt optic neuritis.
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Affiliation(s)
- Sheila Espírito Santo Araújo
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto de Biologia, Programa de Neurociências, Universidade Federal Fluminense, Niterói, Brazil.,Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Henrique Rocha Mendonça
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.,Instituto de Biologia, Programa de Neurociências, Universidade Federal Fluminense, Niterói, Brazil
| | - Natalie A Wheeler
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Paula Campello-Costa
- Instituto de Biologia, Programa de Neurociências, Universidade Federal Fluminense, Niterói, Brazil
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Flávia C A Gomes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Michael A Fox
- Developmental and Translational Neurobiology Center, Virginia Tech Carilion Research Institute, Roanoke, VA, USA
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
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459
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Intracellular Proteolysis of Progranulin Generates Stable, Lysosomal Granulins that Are Haploinsufficient in Patients with Frontotemporal Dementia Caused by GRN Mutations. eNeuro 2017; 4:eN-NWR-0100-17. [PMID: 28828399 PMCID: PMC5562298 DOI: 10.1523/eneuro.0100-17.2017] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/19/2017] [Accepted: 08/01/2017] [Indexed: 01/17/2023] Open
Abstract
Homozygous or heterozygous mutations in the GRN gene, encoding progranulin (PGRN), cause neuronal ceroid lipofuscinosis (NCL) or frontotemporal dementia (FTD), respectively. NCL and FTD are characterized by lysosome dysfunction and neurodegeneration, indicating PGRN is important for lysosome homeostasis in the brain. PGRN is trafficked to the lysosome where its functional role is unknown. PGRN can be cleaved into seven 6-kDa proteins called granulins (GRNs); however, little is known about how GRNs are produced or if levels of GRNs are altered in FTD-GRN mutation carriers. Here, we report the identification and characterization of antibodies that reliably detect several human GRNs by immunoblot and immunocytochemistry. Using these tools, we find that endogenous GRNs are present within multiple cell lines and are constitutively produced. Further, extracellular PGRN is endocytosed and rapidly processed into stable GRNs within lysosomes. Processing of PGRN into GRNs is conserved between humans and mice and is modulated by sortilin expression and mediated by cysteine proteases (i.e. cathpesin L). Induced lysosome dysfunction caused by alkalizing agents or increased expression of transmembrane protein 106B (TMEM106B) inhibit processing of PGRN into GRNs. Finally, we find that multiple GRNs are haploinsufficient in primary fibroblasts and cortical brain tissue from FTD-GRN patients. Taken together, our findings raise the interesting possibility that GRNs carry out critical lysosomal functions and that loss of GRNs should be explored as an initiating factor in lysosomal dysfunction and neurodegeneration caused by GRN mutations.
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460
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Woo J, Han D, Wang JI, Park J, Kim H, Kim Y. Quantitative Proteomics Reveals Temporal Proteomic Changes in Signaling Pathways during BV2 Mouse Microglial Cell Activation. J Proteome Res 2017; 16:3419-3432. [DOI: 10.1021/acs.jproteome.7b00445] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Dohyun Han
- Proteomics
Core Facility, Biomedical Research Institute, Seoul National University Hospital, 101 Daehangro, Seoul 110-799, Korea
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461
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Abud EM, Ramirez RN, Martinez ES, Healy LM, Nguyen CHH, Newman SA, Yeromin AV, Scarfone VM, Marsh SE, Fimbres C, Caraway CA, Fote GM, Madany AM, Agrawal A, Kayed R, Gylys KH, Cahalan MD, Cummings BJ, Antel JP, Mortazavi A, Carson MJ, Poon WW, Blurton-Jones M. iPSC-Derived Human Microglia-like Cells to Study Neurological Diseases. Neuron 2017; 94:278-293.e9. [PMID: 28426964 DOI: 10.1016/j.neuron.2017.03.042] [Citation(s) in RCA: 658] [Impact Index Per Article: 94.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/16/2017] [Accepted: 03/28/2017] [Indexed: 12/15/2022]
Abstract
Microglia play critical roles in brain development, homeostasis, and neurological disorders. Here, we report that human microglial-like cells (iMGLs) can be differentiated from iPSCs to study their function in neurological diseases, like Alzheimer's disease (AD). We find that iMGLs develop in vitro similarly to microglia in vivo, and whole-transcriptome analysis demonstrates that they are highly similar to cultured adult and fetal human microglia. Functional assessment of iMGLs reveals that they secrete cytokines in response to inflammatory stimuli, migrate and undergo calcium transients, and robustly phagocytose CNS substrates. iMGLs were used to examine the effects of Aβ fibrils and brain-derived tau oligomers on AD-related gene expression and to interrogate mechanisms involved in synaptic pruning. Furthermore, iMGLs transplanted into transgenic mice and human brain organoids resemble microglia in vivo. Together, these findings demonstrate that iMGLs can be used to study microglial function, providing important new insight into human neurological disease.
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Affiliation(s)
- Edsel M Abud
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Ricardo N Ramirez
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA
| | - Eric S Martinez
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Luke M Healy
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC H3A 2B4, Canada
| | - Cecilia H H Nguyen
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Sean A Newman
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
| | - Andriy V Yeromin
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA 92697, USA
| | - Vanessa M Scarfone
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
| | - Samuel E Marsh
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Cristhian Fimbres
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Chad A Caraway
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Gianna M Fote
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Abdullah M Madany
- Division of Biomedical Sciences, Center for Glia-Neuronal Interactions, University of California, Riverside, Riverside, CA 92521, USA
| | - Anshu Agrawal
- Department of Medicine, School of Medicine, University of California Irvine, Irvine, CA 92697, USA
| | - Rakez Kayed
- Department of Neurology, George P. and Cynthia Woods Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Karen H Gylys
- UCLA School of Nursing, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael D Cahalan
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA 92697, USA
| | - Brian J Cummings
- Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA; Anatomy and Neurobiology, University of California Irvine, Irvine, CA 92697, USA
| | - Jack P Antel
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC H3A 2B4, Canada
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA
| | - Monica J Carson
- Division of Biomedical Sciences, Center for Glia-Neuronal Interactions, University of California, Riverside, Riverside, CA 92521, USA
| | - Wayne W Poon
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA.
| | - Mathew Blurton-Jones
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA.
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462
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Chang MC, Srinivasan K, Friedman BA, Suto E, Modrusan Z, Lee WP, Kaminker JS, Hansen DV, Sheng M. Progranulin deficiency causes impairment of autophagy and TDP-43 accumulation. J Exp Med 2017; 214:2611-2628. [PMID: 28778989 PMCID: PMC5584112 DOI: 10.1084/jem.20160999] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 04/11/2017] [Accepted: 07/06/2017] [Indexed: 11/05/2022] Open
Abstract
It is unclear how progranulin deficiency causes frontotemporal dementia, a neurodegenerative disease characterized by TDP-43 inclusions. Chang et al. show that loss of progranulin causes impairment of autophagy and autophagy signaling, which leads to accumulation of pathological TDP-43 in neurons. Loss-of-function mutations in GRN cause frontotemporal dementia (FTD) with transactive response DNA-binding protein of 43 kD (TDP-43)–positive inclusions and neuronal ceroid lipofuscinosis (NCL). There are no disease-modifying therapies for either FTD or NCL, in part because of a poor understanding of how mutations in genes such as GRN contribute to disease pathogenesis and neurodegeneration. By studying mice lacking progranulin (PGRN), the protein encoded by GRN, we discovered multiple lines of evidence that PGRN deficiency results in impairment of autophagy, a key cellular degradation pathway. PGRN-deficient mice are sensitive to Listeria monocytogenes because of deficits in xenophagy, a specialized form of autophagy that mediates clearance of intracellular pathogens. Cells lacking PGRN display reduced autophagic flux, and pathological forms of TDP-43 typically cleared by autophagy accumulate more rapidly in PGRN-deficient neurons. Our findings implicate autophagy as a novel therapeutic target for GRN-associated NCL and FTD and highlight the emerging theme of defective autophagy in the broader FTD/amyotrophic lateral sclerosis spectrum of neurodegenerative disease.
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Affiliation(s)
- Michael C Chang
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA
| | | | - Brad A Friedman
- Department of Bioinformatics and Computational Biology, Genentech, Inc., South San Francisco, CA
| | - Eric Suto
- Department of Translational Immunology, Genentech, Inc., South San Francisco, CA
| | - Zora Modrusan
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA
| | - Wyne P Lee
- Department of Translational Immunology, Genentech, Inc., South San Francisco, CA
| | - Joshua S Kaminker
- Department of Bioinformatics and Computational Biology, Genentech, Inc., South San Francisco, CA
| | - David V Hansen
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA
| | - Morgan Sheng
- Department of Neuroscience, Genentech, Inc., South San Francisco, CA
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463
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Schatz-Jakobsen JA, Pedersen DV, Andersen GR. Structural insight into proteolytic activation and regulation of the complement system. Immunol Rev 2017; 274:59-73. [PMID: 27782336 DOI: 10.1111/imr.12465] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complement system is a highly complex and carefully regulated proteolytic cascade activated through three different pathways depending on the activator recognized. The structural knowledge regarding the intricate proteolytic enzymes that activate and control complement has increased dramatically over the last decade. This development has been pivotal for understanding how mutations within complement proteins might contribute to pathogenesis and has spurred new strategies for development of complement therapeutics. Here we describe and discuss the complement system from a structural perspective and integrate the most recent findings obtained by crystallography, small-angle X-ray scattering, and electron microscopy. In particular, we focus on the proteolytic enzymes governing activation and their products carrying the biological effector functions. Additionally, we present the structural basis for some of the best known complement inhibitors. The large number of accumulated molecular structures enables us to visualize the relative size, position, and overall orientation of many of the most interesting complement proteins and assembled complexes on activator surfaces and in membranes.
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Affiliation(s)
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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464
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Lall D, Baloh RH. Microglia and C9orf72 in neuroinflammation and ALS and frontotemporal dementia. J Clin Invest 2017; 127:3250-3258. [PMID: 28737506 DOI: 10.1172/jci90607] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a degenerative disorder that is characterized by loss of motor neurons and shows clinical, pathological, and genetic overlap with frontotemporal dementia (FTD). Activated microglia are a universal feature of ALS/FTD pathology; however, their role in disease pathogenesis remains incompletely understood. The recent discovery that ORF 72 on chromosome 9 (C9orf72), the gene most commonly mutated in ALS/FTD, has an important role in myeloid cells opened the possibility that altered microglial function plays an active role in disease. This Review highlights the contribution of microglia to ALS/FTD pathogenesis, discusses the connection between autoimmunity and ALS/FTD, and explores the possibility that C9orf72 and other ALS/FTD genes may have a "dual effect" on both neuronal and myeloid cell function that could explain a shared propensity for altered systemic immunity and neurodegeneration.
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Affiliation(s)
- Deepti Lall
- Board of Governors Regenerative Medicine Institute and
| | - Robert H Baloh
- Board of Governors Regenerative Medicine Institute and.,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA
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465
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Bohlen CJ, Bennett FC, Tucker AF, Collins HY, Mulinyawe SB, Barres BA. Diverse Requirements for Microglial Survival, Specification, and Function Revealed by Defined-Medium Cultures. Neuron 2017; 94:759-773.e8. [PMID: 28521131 DOI: 10.1016/j.neuron.2017.04.043] [Citation(s) in RCA: 413] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 03/31/2017] [Accepted: 04/28/2017] [Indexed: 12/14/2022]
Abstract
Microglia, the resident macrophages of the CNS, engage in various CNS-specific functions that are critical for development and health. To better study microglia and the properties that distinguish them from other tissue macrophage populations, we have optimized serum-free culture conditions to permit robust survival of highly ramified adult microglia under defined-medium conditions. We find that astrocyte-derived factors prevent microglial death ex vivo and that this activity results from three primary components, CSF-1/IL-34, TGF-β2, and cholesterol. Using microglial cultures that have never been exposed to serum, we demonstrate a dramatic and lasting change in phagocytic capacity after serum exposure. Finally, we find that mature microglia rapidly lose signature gene expression after isolation, and that this loss can be reversed by engrafting cells back into an intact CNS environment. These data indicate that the specialized gene expression profile of mature microglia requires continuous instructive signaling from the intact CNS.
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Affiliation(s)
- Christopher J Bohlen
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - F Chris Bennett
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew F Tucker
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Hannah Y Collins
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sara B Mulinyawe
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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466
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She A, Kurtser I, Reis SA, Hennig K, Lai J, Lang A, Zhao WN, Mazitschek R, Dickerson BC, Herz J, Haggarty SJ. Selectivity and Kinetic Requirements of HDAC Inhibitors as Progranulin Enhancers for Treating Frontotemporal Dementia. Cell Chem Biol 2017; 24:892-906.e5. [PMID: 28712747 DOI: 10.1016/j.chembiol.2017.06.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 02/06/2017] [Accepted: 06/19/2017] [Indexed: 11/18/2022]
Abstract
Frontotemporal dementia (FTD) arises from neurodegeneration in the frontal, insular, and anterior temporal lobes. Autosomal dominant causes of FTD include heterozygous mutations in the GRN gene causing haploinsufficiency of progranulin (PGRN) protein. Recently, histone deacetylase (HDAC) inhibitors have been identified as enhancers of PGRN expression, although the mechanisms through which GRN is epigenetically regulated remain poorly understood. Using a chemogenomic toolkit, including optoepigenetic probes, we show that inhibition of class I HDACs is sufficient to upregulate PGRN in human neurons, and only inhibitors with apparent fast binding to their target HDAC complexes are capable of enhancing PGRN expression. Moreover, we identify regions in the GRN promoter in which elevated H3K27 acetylation and transcription factor EB (TFEB) occupancy correlate with HDAC-inhibitor-mediated upregulation of PGRN. These findings have implications for epigenetic and cis-regulatory mechanisms controlling human GRN expression and may advance translational efforts to develop targeted therapeutics for treating PGRN-deficient FTD.
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Affiliation(s)
- Angela She
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Iren Kurtser
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Surya A Reis
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Krista Hennig
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Jenny Lai
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Audrey Lang
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Wen-Ning Zhao
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Ralph Mazitschek
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Bradford C Dickerson
- MGH Frontotemporal Disorders Unit, Gerontology Research Unit, Alzheimer's Disease Research Center, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Joachim Herz
- Departments of Molecular Genetics, Neuroscience, Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9046, USA
| | - Stephen J Haggarty
- Chemical Neurobiology Laboratory, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA.
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467
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Ward ME, Chen R, Huang HY, Ludwig C, Telpoukhovskaia M, Taubes A, Boudin H, Minami SS, Reichert M, Albrecht P, Gelfand JM, Cruz-Herranz A, Cordano C, Alavi MV, Leslie S, Seeley WW, Miller BL, Bigio E, Mesulam MM, Bogyo MS, Mackenzie IR, Staropoli JF, Cotman SL, Huang EJ, Gan L, Green AJ. Individuals with progranulin haploinsufficiency exhibit features of neuronal ceroid lipofuscinosis. Sci Transl Med 2017; 9:9/385/eaah5642. [PMID: 28404863 DOI: 10.1126/scitranslmed.aah5642] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 07/14/2016] [Accepted: 11/21/2016] [Indexed: 01/03/2023]
Abstract
Heterozygous mutations in the GRN gene lead to progranulin (PGRN) haploinsufficiency and cause frontotemporal dementia (FTD), a neurodegenerative syndrome of older adults. Homozygous GRN mutations, on the other hand, lead to complete PGRN loss and cause neuronal ceroid lipofuscinosis (NCL), a lysosomal storage disease usually seen in children. Given that the predominant clinical and pathological features of FTD and NCL are distinct, it is controversial whether the disease mechanisms associated with complete and partial PGRN loss are similar or distinct. We show that PGRN haploinsufficiency leads to NCL-like features in humans, some occurring before dementia onset. Noninvasive retinal imaging revealed preclinical retinal lipofuscinosis in heterozygous GRN mutation carriers. Increased lipofuscinosis and intracellular NCL-like storage material also occurred in postmortem cortex of heterozygous GRN mutation carriers. Lymphoblasts from heterozygous GRN mutation carriers accumulated prominent NCL-like storage material, which could be rescued by normalizing PGRN expression. Fibroblasts from heterozygous GRN mutation carriers showed impaired lysosomal protease activity. Our findings indicate that progranulin haploinsufficiency caused accumulation of NCL-like storage material and early retinal abnormalities in humans and implicate lysosomal dysfunction as a central disease process in GRN-associated FTD and GRN-associated NCL.
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Affiliation(s)
- Michael E Ward
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA.,National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Robert Chen
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA.,Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hsin-Yi Huang
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94158, USA.,Department of Pathology, National Taiwan University Hospital, Taipei City, Taiwan
| | - Connor Ludwig
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA.,Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Maria Telpoukhovskaia
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Ali Taubes
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Helene Boudin
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94158, USA.,INSERM UMR 913, Université de Nantes, Nantes, France
| | - Sakura S Minami
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Meredith Reichert
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Philipp Albrecht
- Department of Neurology, Medical Faculty, Heinrich-Heine University Duesseldorf, Duesseldorf, Germany
| | - Jeffrey M Gelfand
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andres Cruz-Herranz
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Christian Cordano
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Marcel V Alavi
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shannon Leslie
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - William W Seeley
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bruce L Miller
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Eileen Bigio
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Marek-Marsel Mesulam
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Matthew S Bogyo
- Department of Pathology, Stanford Medical School, Palo Alto, CA 94305, USA
| | - Ian R Mackenzie
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - John F Staropoli
- Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Susan L Cotman
- Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Eric J Huang
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94158, USA.,Pathology Service, Veterans Affairs Medical Center, San Francisco, CA 94141, USA
| | - Li Gan
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA. .,Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ari J Green
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA. .,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
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468
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Herz J, Filiano AJ, Wiltbank AT, Yogev N, Kipnis J. Myeloid Cells in the Central Nervous System. Immunity 2017; 46:943-956. [PMID: 28636961 PMCID: PMC5657250 DOI: 10.1016/j.immuni.2017.06.007] [Citation(s) in RCA: 239] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/17/2017] [Accepted: 06/02/2017] [Indexed: 02/07/2023]
Abstract
The central nervous system (CNS) and its meningeal coverings accommodate a diverse myeloid compartment that includes parenchymal microglia and perivascular macrophages, as well as choroid plexus and meningeal macrophages, dendritic cells, and granulocytes. These myeloid populations enjoy an intimate relationship with the CNS, where they play an essential role in both health and disease. Although the importance of these cells is clearly recognized, their exact function in the CNS continues to be explored. Here, we review the subsets of myeloid cells that inhabit the parenchyma, meninges, and choroid plexus and discuss their roles in CNS homeostasis. We also discuss the role of these cells in various neurological pathologies, such as autoimmunity, mechanical injury, neurodegeneration, and infection. We highlight the neuroprotective nature of certain myeloid cells by emphasizing their therapeutic potential for the treatment of neurological conditions.
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Affiliation(s)
- Jasmin Herz
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Anthony J Filiano
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
| | - Ashtyn T Wiltbank
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Nir Yogev
- Gutenberg Research Fellowship Group of Neuroimmunology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Gutenberg Research Fellowship Group of Neuroimmunology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
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469
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Meeter LH, Kaat LD, Rohrer JD, van Swieten JC. Imaging and fluid biomarkers in frontotemporal dementia. Nat Rev Neurol 2017. [PMID: 28621768 DOI: 10.1038/nrneurol.2017.75] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Frontotemporal dementia (FTD), the second most common type of presenile dementia, is a heterogeneous neurodegenerative disease characterized by progressive behavioural and/or language problems, and includes a range of clinical, genetic and pathological subtypes. The diagnostic process is hampered by this heterogeneity, and correct diagnosis is becoming increasingly important to enable future clinical trials of disease-modifying treatments. Reliable biomarkers will enable us to better discriminate between FTD and other forms of dementia and to predict disease progression in the clinical setting. Given that different underlying pathologies probably require specific pharmacological interventions, robust biomarkers are essential for the selection of patients with specific FTD subtypes. This Review emphasizes the increasing availability and potential applications of structural and functional imaging biomarkers, and cerebrospinal fluid and blood fluid biomarkers in sporadic and genetic FTD. The relevance of new MRI modalities - such as voxel-based morphometry, diffusion tensor imaging and arterial spin labelling - in the early stages of FTD is discussed, together with the ability of these modalities to classify FTD subtypes. We highlight promising new fluid biomarkers for staging and monitoring of FTD, and underline the importance of large, multicentre studies of individuals with presymptomatic FTD. Harmonization in the collection and analysis of data across different centres is crucial for the implementation of new biomarkers in clinical practice, and will become a great challenge in the next few years.
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Affiliation(s)
- Lieke H Meeter
- Department of Neurology, Erasmus Medical Center, 's Gravendijkwal 230, 3015 CE Rotterdam, Netherlands
| | - Laura Donker Kaat
- Department of Neurology, Erasmus Medical Center, 's Gravendijkwal 230, 3015 CE Rotterdam, Netherlands.,Department of Clinical Genetics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, Netherlands
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative diseases, Institute of Neurology, Queen Square, University College London, London WC1N 3BG, UK
| | - John C van Swieten
- Department of Neurology, Erasmus Medical Center, 's Gravendijkwal 230, 3015 CE Rotterdam, Netherlands.,Department of Clinical Genetics, VU University Medical Center, De Boelelaan 1118, 1081 HZ Amsterdam, Netherlands
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470
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Thielens NM, Tedesco F, Bohlson SS, Gaboriaud C, Tenner AJ. C1q: A fresh look upon an old molecule. Mol Immunol 2017; 89:73-83. [PMID: 28601358 DOI: 10.1016/j.molimm.2017.05.025] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/27/2017] [Accepted: 05/29/2017] [Indexed: 12/14/2022]
Abstract
Originally discovered as part of C1, the initiation component of the classical complement pathway, it is now appreciated that C1q regulates a variety of cellular processes independent of complement activation. C1q is a complex glycoprotein assembled from 18 polypeptide chains, with a C-terminal globular head region that mediates recognition of diverse molecular structures, and an N-terminal collagen-like tail that mediates immune effector mechanisms. C1q mediates a variety of immunoregulatory functions considered important in the prevention of autoimmunity such as the enhancement of phagocytosis, regulation of cytokine production by antigen presenting cells, and subsequent alteration in T-lymphocyte maturation. Furthermore, recent advances indicate additional roles for C1q in diverse physiologic and pathologic processes including pregnancy, tissue repair, and cancer. Finally, C1q is emerging as a critical component of neuronal network refinement and homeostatic regulation within the central nervous system. This review summarizes the classical functions of C1q and reviews novel discoveries within the field.
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Affiliation(s)
| | - Francesco Tedesco
- Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, Milan, Italy
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471
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Impaired prosaposin lysosomal trafficking in frontotemporal lobar degeneration due to progranulin mutations. Nat Commun 2017; 8:15277. [PMID: 28541286 PMCID: PMC5477518 DOI: 10.1038/ncomms15277] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/15/2017] [Indexed: 01/01/2023] Open
Abstract
Haploinsufficiency of progranulin (PGRN) due to mutations in the granulin (GRN) gene causes frontotemporal lobar degeneration (FTLD), and complete loss of PGRN leads to a lysosomal storage disorder, neuronal ceroid lipofuscinosis (NCL). Accumulating evidence suggests that PGRN is essential for proper lysosomal function, but the precise mechanisms involved are not known. Here, we show that PGRN facilitates neuronal uptake and lysosomal delivery of prosaposin (PSAP), the precursor of saposin peptides that are essential for lysosomal glycosphingolipid degradation. We found reduced levels of PSAP in neurons both in mice deficient in PGRN and in human samples from FTLD patients due to GRN mutations. Furthermore, mice with reduced PSAP expression demonstrated FTLD-like pathology and behavioural changes. Thus, our data demonstrate a role of PGRN in PSAP lysosomal trafficking and suggest that impaired lysosomal trafficking of PSAP is an underlying disease mechanism for NCL and FTLD due to GRN mutations. Mutations in the granulin gene are associated with frontotemporal lobe dementia (FTLD) and a lysosomal storage disease. The authors show that reduced progranulin levels leads to impaired neuronal uptake and lysosomal delivery of prosaposin, and that decreased prosaposin expression in mice leads to FTLD-like behaviour.
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472
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Kata D, Földesi I, Feher LZ, Hackler L, Puskas LG, Gulya K. A novel pleiotropic effect of aspirin: Beneficial regulation of pro- and anti-inflammatory mechanisms in microglial cells. Brain Res Bull 2017; 132:61-74. [PMID: 28528204 DOI: 10.1016/j.brainresbull.2017.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 04/27/2017] [Accepted: 05/12/2017] [Indexed: 02/07/2023]
Abstract
Aspirin, one of the most widely used non-steroidal anti-inflammatory drugs, has extensively studied effects on the cardiovascular system. To reveal further pleiotropic, beneficial effects of aspirin on a number of pro- and anti-inflammatory microglial mechanisms, we performed morphometric and functional studies relating to phagocytosis, pro- and anti-inflammatory cytokine production (IL-1β, tumor necrosis factor-α (TNF-α) and IL-10, respectively) and analyzed the expression of a number of inflammation-related genes, including those related to the above functions, in pure microglial cells. We examined the effects of aspirin (0.1mM and 1mM) in unchallenged (control) and bacterial lipopolysaccharide (LPS)-challenged secondary microglial cultures. Aspirin affected microglial morphology and functions in a dose-dependent manner as it inhibited LPS-elicited microglial activation by promoting ramification and the inhibition of phagocytosis in both concentrations. Remarkably, aspirin strongly reduced the pro-inflammatory IL-1β and TNF-α production, while it increased the anti-inflammatory IL-10 level in LPS-challenged cells. Moreover, aspirin differentially regulated the expression of a number of inflammation-related genes as it downregulated such pro-inflammatory genes as Nos2, Kng1, IL1β, Ptgs2 or Ccr1, while it upregulated some anti-inflammatory genes such as IL10, Csf2, Cxcl1, Ccl5 or Tgfb1. Thus, the use of aspirin could be beneficial for the prophylaxis of certain neurodegenerative disorders as it effectively ameliorates inflammation in the brain.
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Affiliation(s)
- Diana Kata
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary.
| | - Imre Földesi
- Department of Laboratory Medicine, University of Szeged, Szeged, Hungary.
| | | | | | | | - Karoly Gulya
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary.
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473
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Tanaka Y, Suzuki G, Matsuwaki T, Hosokawa M, Serrano G, Beach TG, Yamanouchi K, Hasegawa M, Nishihara M. Progranulin regulates lysosomal function and biogenesis through acidification of lysosomes. Hum Mol Genet 2017; 26:969-988. [PMID: 28073925 DOI: 10.1093/hmg/ddx011] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 01/05/2017] [Indexed: 11/12/2022] Open
Abstract
Progranulin (PGRN) haploinsufficiency resulting from loss-of-function mutations in the PGRN gene causes frontotemporal lobar degeneration accompanied by TDP-43 accumulation, and patients with homozygous mutations in the PGRN gene present with neuronal ceroid lipofuscinosis. Although it remains unknown why PGRN deficiency causes neurodegenerative diseases, there is increasing evidence that PGRN is implicated in lysosomal functions. Here, we show PGRN is a secretory lysosomal protein that regulates lysosomal function and biogenesis by controlling the acidification of lysosomes. PGRN gene expression and protein levels increased concomitantly with the increase of lysosomal biogenesis induced by lysosome alkalizers or serum starvation. Down-regulation or insufficiency of PGRN led to the increased lysosomal gene expression and protein levels, while PGRN overexpression led to the decreased lysosomal gene expression and protein levels. In particular, the level of mature cathepsin D (CTSDmat) dramatically changed depending upon PGRN levels. The acidification of lysosomes was facilitated in cells transfected with PGRN. Then, this caused degradation of CTSDmat by cathepsin B. Secreted PGRN is incorporated into cells via sortilin or cation-independent mannose 6-phosphate receptor, and facilitated the acidification of lysosomes and degradation of CTSDmat. Moreover, the change of PGRN levels led to a cell-type-specific increase of insoluble TDP-43. In the brain tissue of FTLD-TDP patients with PGRN deficiency, CTSD and phosphorylated TDP-43 accumulated in neurons. Our study provides new insights into the physiological function of PGRN and the role of PGRN insufficiency in the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Yoshinori Tanaka
- Department of Dementia and Higher Brain function, Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.,Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Genjiro Suzuki
- Department of Dementia and Higher Brain function, Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Takashi Matsuwaki
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masato Hosokawa
- Department of Dementia and Higher Brain function, Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Geidy Serrano
- Civin Laboratory for Neuropathology, Banner Sun Health Research Institute, 10515 West Santa Fe Drive, Sun City AZ 85351, USA
| | - Thomas G Beach
- Civin Laboratory for Neuropathology, Banner Sun Health Research Institute, 10515 West Santa Fe Drive, Sun City AZ 85351, USA
| | - Keitaro Yamanouchi
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masato Hasegawa
- Department of Dementia and Higher Brain function, Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Masugi Nishihara
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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474
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Paolicelli RC, Ferretti MT. Function and Dysfunction of Microglia during Brain Development: Consequences for Synapses and Neural Circuits. Front Synaptic Neurosci 2017; 9:9. [PMID: 28539882 PMCID: PMC5423952 DOI: 10.3389/fnsyn.2017.00009] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 04/27/2017] [Indexed: 01/02/2023] Open
Abstract
Many diverse factors, ranging from stress to infections, can perturb brain homeostasis and alter the physiological activity of microglia, the immune cells of the central nervous system. Microglia play critical roles in the process of synaptic maturation and brain wiring during development. Any perturbation affecting microglial physiological function during critical developmental periods could result in defective maturation of synaptic circuits. In this review, we critically appraise the recent literature on the alterations of microglial activity induced by environmental and genetic factors occurring at pre- and early post-natal stages. Furthermore, we discuss the long-lasting consequences of early-life microglial perturbation on synaptic function and on vulnerability to neurodevelopmental and psychiatric disorders.
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Affiliation(s)
- Rosa C Paolicelli
- IREM, Institute for Regenerative Medicine, University of ZurichZürich, Switzerland.,ZNZ Neuroscience Center ZurichZürich, Switzerland
| | - Maria T Ferretti
- IREM, Institute for Regenerative Medicine, University of ZurichZürich, Switzerland.,ZNZ Neuroscience Center ZurichZürich, Switzerland
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475
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Magrinelli F, Pezzini F, Moro F, Santorelli FM, Simonati A. Diagnostic methods and emerging treatments for adult neuronal ceroid lipofuscinoses (Kufs disease). Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1325359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Francesca Magrinelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Francesco Pezzini
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Francesca Moro
- Molecular Medicine and Neurogenetics Unit, IRCCS Stella Maris, Pisa, Italy
| | | | - Alessandro Simonati
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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476
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Krabbe G, Minami SS, Etchegaray JI, Taneja P, Djukic B, Davalos D, Le D, Lo I, Zhan L, Reichert MC, Sayed F, Merlini M, Ward ME, Perry DC, Lee SE, Sias A, Parkhurst CN, Gan WB, Akassoglou K, Miller BL, Farese RV, Gan L. Microglial NFκB-TNFα hyperactivation induces obsessive-compulsive behavior in mouse models of progranulin-deficient frontotemporal dementia. Proc Natl Acad Sci U S A 2017; 114:5029-5034. [PMID: 28438992 PMCID: PMC5441749 DOI: 10.1073/pnas.1700477114] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Frontotemporal dementia (FTD) is the second most common dementia before 65 years of age. Haploinsufficiency in the progranulin (GRN) gene accounts for 10% of all cases of familial FTD. GRN mutation carriers have an increased risk of autoimmune disorders, accompanied by elevated levels of tissue necrosis factor (TNF) α. We examined behavioral alterations related to obsessive-compulsive disorder (OCD) and the role of TNFα and related signaling pathways in FTD patients with GRN mutations and in mice lacking progranulin (PGRN). We found that patients and mice with GRN mutations displayed OCD and self-grooming (an OCD-like behavior in mice), respectively. Furthermore, medium spiny neurons in the nucleus accumbens, an area implicated in development of OCD, display hyperexcitability in PGRN knockout mice. Reducing levels of TNFα in PGRN knockout mice abolished excessive self-grooming and the associated hyperexcitability of medium spiny neurons of the nucleus accumbens. In the brain, PGRN is highly expressed in microglia, which are a major source of TNFα. We therefore deleted PGRN specifically in microglia and found that it was sufficient to induce excessive grooming. Importantly, excessive grooming in these mice was prevented by inactivating nuclear factor κB (NF-κB) in microglia/myeloid cells. Our findings suggest that PGRN deficiency leads to excessive NF-κB activation in microglia and elevated TNFα signaling, which in turn lead to hyperexcitability of medium spiny neurons and OCD-like behavior.
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Affiliation(s)
- Grietje Krabbe
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - S Sakura Minami
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Jon I Etchegaray
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Praveen Taneja
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
| | - Biljana Djukic
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
| | - Dimitrios Davalos
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
| | - David Le
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
| | - Iris Lo
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
| | - Lihong Zhan
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Meredith C Reichert
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Faten Sayed
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
| | - Mario Merlini
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
| | - Michael E Ward
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - David C Perry
- Department of Neurology, University of California, San Francisco, CA 94158
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158
| | - Suzee E Lee
- Department of Neurology, University of California, San Francisco, CA 94158
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158
| | - Ana Sias
- Department of Neurology, University of California, San Francisco, CA 94158
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158
| | - Christopher N Parkhurst
- Skirball Institute of Biomolecular Medicine, New York University Medical Center, New York, NY 10016
| | - Wen-Biao Gan
- Skirball Institute of Biomolecular Medicine, New York University Medical Center, New York, NY 10016
| | - Katerina Akassoglou
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Bruce L Miller
- Department of Neurology, University of California, San Francisco, CA 94158
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158
| | - Robert V Farese
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA 02115
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Li Gan
- Gladstone Institute of Neurological Diseases, University of California, San Francisco, CA 94158;
- Department of Neurology, University of California, San Francisco, CA 94158
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
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477
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Ma Y, Matsuwaki T, Yamanouchi K, Nishihara M. Involvement of progranulin in modulating neuroinflammatory responses but not neurogenesis in the hippocampus of aged mice. Exp Gerontol 2017; 95:1-8. [PMID: 28479389 DOI: 10.1016/j.exger.2017.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 04/28/2017] [Accepted: 05/02/2017] [Indexed: 10/19/2022]
Abstract
It is well established that adult neurogenesis in the hippocampus declines with age. Our previous studies have suggested that progranulin (PGRN) has a facilitative effect on hippocampal neurogenesis. We have also shown that PGRN plays a role in suppressing excessive neuroinflammatory responses in the cortex and thalamus after brain injury and aging, respectively. However, the roles of PGRN in modulating neurogenesis and neuroinflammatory responses in the hippocampus of aged animals are not yet understood. In the present study, we investigated neurogenesis and neuroinflammation-related responses in the hippocampus of young (15-week-old) and old (135-week-old) wild-type and PGRN-deficient male mice. Neurogenesis in the dentate gyrus of the hippocampus markedly declined with age, and there was no significant difference between the genotype. The number of CD68-positive activated microglia and the expression of lysosomal genes in the hippocampus were significantly increased with age, and PGRN deficiency further increased them. The expression of pro-inflammatory genes was also increased with age, and PGRN deficiency significantly enhanced some of them. These results suggest that PGRN deficiency exacerbates neuroinflammatory responses related to activated microglia in aged animals, while PGRN may not counteract the decline of hippocampal neurogenesis with age.
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Affiliation(s)
- Yanbo Ma
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; Department of Animal Physiology, College of Animal Science, Henan University of Science and Technology, Luoyang 471003, China
| | - Takashi Matsuwaki
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Keitaro Yamanouchi
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Masugi Nishihara
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
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478
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Takahashi H, Klein ZA, Bhagat SM, Kaufman AC, Kostylev MA, Ikezu T, Strittmatter SM. Opposing effects of progranulin deficiency on amyloid and tau pathologies via microglial TYROBP network. Acta Neuropathol 2017; 133:785-807. [PMID: 28070672 PMCID: PMC5391267 DOI: 10.1007/s00401-017-1668-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/02/2017] [Accepted: 01/04/2017] [Indexed: 02/08/2023]
Abstract
Progranulin (PGRN) is implicated in Alzheimer's disease (AD) as well as frontotemporal lobar degeneration. Genetic studies demonstrate an association of the common GRN rs5848 variant that results in reduced PGRN levels with increased risk for AD. However, the mechanisms by which PGRN reduction from the GRN AD risk variant or mutation exacerbates AD pathophysiology remain ill defined. Here, we show that the GRN AD risk variant has no significant effects on florbetapir positron emission tomographic amyloid imaging and cerebrospinal fluid (CSF) Aβ levels, whereas it is associated with increased CSF tau levels in human subjects of the Alzheimer's disease neuroimaging initiative studies. Consistent with the human data, subsequent analyses using the APPswe/PS1ΔE9 (APP/PS1) mouse model of cerebral amyloidosis show that PGRN deficiency has no exacerbating effects on Aβ pathology. In contrast and unexpectedly, PGRN deficiency significantly reduces diffuse Aβ plaque growth in these APP/PS1 mice. This protective effect is due, at least in part, to enhanced microglial Aβ phagocytosis caused by PGRN deficiency-induced expression of TYROBP network genes (TNG) including an AD risk factor Trem2. PGRN-deficient APP/PS1 mice also exhibit less severe axonal dystrophy and partially improved behavior phenotypes. While PGRN deficiency reduces these amyloidosis-related phenotypes, other neuronal injury mechanisms are increased by loss of PGRN, revealing a multidimensional interaction of GRN with AD. For example, C1q complement deposition at synapses is enhanced in APP/PS1 mice lacking PGRN. Moreover, PGRN deficiency increases tau AT8 and AT180 pathologies in human P301L tau-expressing mice. These human and rodent data suggest that global PGRN reduction induces microglial TNG expression and increases AD risk by exacerbating neuronal injury and tau pathology, rather than by accelerating Aβ pathology.
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Affiliation(s)
- Hideyuki Takahashi
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Zoe A Klein
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Sarah M Bhagat
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Adam C Kaufman
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Mikhail A Kostylev
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Tsuneya Ikezu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Stephen M Strittmatter
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT, 06536, USA.
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479
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Abstract
The discovery that heterozygous and homozygous mutations in the gene encoding progranulin are causally linked to frontotemporal dementia and lysosomal storage disease, respectively, reveals previously unrecognized roles of the progranulin protein in regulating lysosome biogenesis and function. Given the importance of lysosomes in cellular homeostasis, it is not surprising that progranulin deficiency has pleiotropic effects on neural circuit development and maintenance, stress response, innate immunity and ageing. This Progress article reviews recent advances in progranulin biology emphasizing its roles in lysosomal function and brain innate immunity, and outlines future avenues of investigation that may lead to new therapeutic approaches for neurodegeneration.
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480
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Therapeutic Potentials of Synapses after Traumatic Brain Injury: A Comprehensive Review. Neural Plast 2017; 2017:4296075. [PMID: 28491479 PMCID: PMC5405590 DOI: 10.1155/2017/4296075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/09/2017] [Accepted: 03/14/2017] [Indexed: 12/26/2022] Open
Abstract
Massive studies have focused on the understanding of the pathobiology of cellular and molecular changes and injury mechanisms after traumatic brain injury (TBI), but very few studies have specially discussed the role of synapses in the context of TBI. This paper specifically highlights the role and therapeutic potentials of synapses after TBI. First, we review and conclude how synapses interact with constant structural, metabolic, neuroendocrine, and inflammatory mechanisms after TBI. Second, we briefly describe several key synaptic proteins involved in neuroplasticity, which may be novel neuronal targets for specific intervention. Third, we address therapeutic interventions in association with synapses after TBI. Finally, we concisely discuss the study gaps in the synapses after TBI, in hopes that this would provide more insights for future studies. Synapses play an important role in TBI; while the understandings on the synaptic participation in the treatments and prognosis of TBI are lacking, more studies in this area are warranted.
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481
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Amick J, Ferguson SM. C9orf72: At the intersection of lysosome cell biology and neurodegenerative disease. Traffic 2017; 18:267-276. [PMID: 28266105 DOI: 10.1111/tra.12477] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 12/13/2022]
Abstract
The discovery that expansion of a hexanucleotide repeat within a noncoding region of the C9orf72 gene causes amyotrophic lateral sclerosis and frontotemporal dementia raised questions about C9orf72 protein function and potential disease relevance. The major predicted structural feature of the C9orf72 protein is a DENN (differentially expressed in normal and neoplastic cells) domain. As DENN domains are best characterized for regulation of specific Rab GTPases, it has been proposed that C9orf72 may also act through regulation of a GTPase target. Recent genetic and cell biological studies furthermore indicate that the C9orf72 protein functions at lysosomes as part of a larger complex that also contains the Smith-Magenis chromosome region 8 (SMCR8) and WD repeat-containing protein 41 (WDR41) proteins. An important role for C9orf72 at lysosomes is supported by defects in lysosome morphology and mTOR complex 1 (mTORC1) signaling arising from C9orf72 KO in diverse model systems. Collectively, these new findings define a C9orf72-containing protein complex and a lysosomal site of action as central to C9orf72 function and provide a foundation for the elucidation of direct physiological targets for C9orf72. Further elucidation of mechanisms whereby C9orf72 regulates lysosome function will help to determine how the reductions in C9orf72 expression levels that accompany hexanucleotide repeat expansions contribute to disease pathology.
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Affiliation(s)
- Joseph Amick
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut
| | - Shawn M Ferguson
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut
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482
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Microglia activation due to obesity programs metabolic failure leading to type two diabetes. Nutr Diabetes 2017; 7:e254. [PMID: 28319103 PMCID: PMC5380893 DOI: 10.1038/nutd.2017.10] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/04/2016] [Accepted: 01/22/2017] [Indexed: 02/06/2023] Open
Abstract
Obesity is an energy metabolism disorder that increases susceptibility to the development of metabolic diseases. Recently, it has been described that obese subjects have a phenotype of chronic inflammation in organs that are metabolically relevant for glucose homeostasis and energy. Altered expression of immune system molecules such as interleukins IL-1, IL-6, IL-18, tumor necrosis factor alpha (TNF-α), serum amyloid A (SAA), and plasminogen activator inhibitor-1 (PAI-1), among others, has been associated with the development of chronic inflammation in obesity. Chronic inflammation modulates the development of metabolic-related comorbidities like metabolic syndrome (insulin resistance, glucose tolerance, hypertension and hyperlipidemia). Recent evidence suggests that microglia activation in the central nervous system (CNS) is a priority in the deregulation of energy homeostasis and promotes increased glucose levels. This review will cover the most significant advances that explore the molecular signals during microglia activation and inflammatory stage in the brain in the context of obesity, and its influence on the development of metabolic syndrome and type two diabetes.
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483
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Plaza-Zabala A, Sierra-Torre V, Sierra A. Autophagy and Microglia: Novel Partners in Neurodegeneration and Aging. Int J Mol Sci 2017; 18:E598. [PMID: 28282924 PMCID: PMC5372614 DOI: 10.3390/ijms18030598] [Citation(s) in RCA: 217] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 02/28/2017] [Accepted: 03/05/2017] [Indexed: 02/07/2023] Open
Abstract
Autophagy is emerging as a core regulator of Central Nervous System (CNS) aging and neurodegeneration. In the brain, it has mostly been studied in neurons, where the delivery of toxic molecules and organelles to the lysosome by autophagy is crucial for neuronal health and survival. However, we propose that the (dys)regulation of autophagy in microglia also affects innate immune functions such as phagocytosis and inflammation, which in turn contribute to the pathophysiology of aging and neurodegenerative diseases. Herein, we first describe the basic concepts of autophagy and its regulation, discuss key aspects for its accurate monitoring at the experimental level, and summarize the evidence linking autophagy impairment to CNS senescence and disease. We focus on acute, chronic, and autoimmunity-mediated neurodegeneration, including ischemia/stroke, Alzheimer's, Parkinson's, and Huntington's diseases, and multiple sclerosis. Next, we describe the actual and potential impact of autophagy on microglial phagocytic and inflammatory function. Thus, we provide evidence of how autophagy may affect microglial phagocytosis of apoptotic cells, amyloid-β, synaptic material, and myelin debris, and regulate the progression of age-associated neurodegenerative diseases. We also discuss data linking autophagy to the regulation of the microglial inflammatory phenotype, which is known to contribute to age-related brain dysfunction. Overall, we update the current knowledge of autophagy and microglia, and highlight as yet unexplored mechanisms whereby autophagy in microglia may contribute to CNS disease and senescence.
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Affiliation(s)
| | | | - Amanda Sierra
- Achucarro Basque Center for Neuroscience, 48170 Zamudio, Spain.
- Department of Neurosciences, University of the Basque Country EHU/UPV, 48940 Leioa, Spain.
- Ikerbasque Foundation, 48013 Bilbao, Spain.
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484
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Fonseca MI, Chu SH, Hernandez MX, Fang MJ, Modarresi L, Selvan P, MacGregor GR, Tenner AJ. Cell-specific deletion of C1qa identifies microglia as the dominant source of C1q in mouse brain. J Neuroinflammation 2017; 14:48. [PMID: 28264694 PMCID: PMC5340039 DOI: 10.1186/s12974-017-0814-9] [Citation(s) in RCA: 225] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/07/2017] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The complement cascade not only provides protection from infection but can also mediate destructive inflammation. Complement is also involved in elimination of neuronal synapses which is essential for proper development, but can be detrimental during aging and disease. C1q, required for several of these complement-mediated activities, is present in the neuropil, microglia, and a subset of interneurons in the brain. METHODS To identify the source(s) of C1q in the brain, the C1qa gene was selectively inactivated in the microglia or Thy-1+ neurons in both wild type mice and a mouse model of Alzheimer's disease (AD), and C1q synthesis assessed by immunohistochemistry, QPCR, and western blot analysis. RESULTS While C1q expression in the brain was unaffected after inactivation of C1qa in Thy-1+ neurons, the brains of C1qa FL/FL :Cx3cr1 CreERT2 mice in which C1qa was ablated in microglia were devoid of C1q with the exception of limited C1q in subsets of interneurons. Surprisingly, this loss of C1q occurred even in the absence of tamoxifen by 1 month of age, demonstrating that Cre activity is tamoxifen-independent in microglia in Cx3cr1 CreERT2/WganJ mice. C1q expression in C1qa FL/FL : Cx3cr1 CreERT2/WganJ mice continued to decline and remained almost completely absent through aging and in AD model mice. No difference in C1q was detected in the liver or kidney from C1qa FL/FL : Cx3cr1 CreERT2/WganJ mice relative to controls, and C1qa FL/FL : Cx3cr1 CreERT2/WganJ mice had minimal, if any, reduction in plasma C1q. CONCLUSIONS Thus, microglia, but not neurons or peripheral sources, are the dominant source of C1q in the brain. While demonstrating that the Cx3cr1 CreERT2/WganJ deleter cannot be used for adult-induced deletion of genes in microglia, the model described here enables further investigation of physiological roles of C1q in the brain and identification of therapeutic targets for the selective control of complement-mediated activities contributing to neurodegenerative disorders.
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Affiliation(s)
- Maria I Fonseca
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Shu-Hui Chu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Michael X Hernandez
- Department of Pathology and Laboratory Medicine, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA
| | - Melody J Fang
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Lila Modarresi
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Pooja Selvan
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Grant R MacGregor
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, 92697, USA
| | - Andrea J Tenner
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697, USA. .,Department of Pathology and Laboratory Medicine, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA. .,Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, 92697, USA.
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485
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Patient-specific models of microglia-mediated engulfment of synapses and neural progenitors. Mol Psychiatry 2017; 22:170-177. [PMID: 27956744 PMCID: PMC5285468 DOI: 10.1038/mp.2016.220] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 12/21/2022]
Abstract
Engulfment of synapses and neural progenitor cells (NPCs) by microglia is critical for the development and maintenance of proper brain circuitry, and has been implicated in neurodevelopmental as well as neurodegenerative disease etiology. We have developed and validated models of these mechanisms by reprogramming microglia-like cells from peripheral blood mononuclear cells, and combining them with NPCs and neurons derived from induced pluripotent stem cells to create patient-specific cellular models of complement-dependent synaptic pruning and elimination of NPCs. The resulting microglia-like cells express appropriate markers and function as primary human microglia, while patient-matched macrophages differ markedly. As a demonstration of disease-relevant application, we studied the role of C4, recently implicated in schizophrenia, in engulfment of synaptic structures by human microglia. The ability to create complete patient-specific cellular models of critical microglial functions utilizing samples taken during a single clinical visit will extend the ability to model central nervous system disease while facilitating high-throughput screening.
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486
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Vieira MNN, Lyra E Silva NM, Ferreira ST, De Felice FG. Protein Tyrosine Phosphatase 1B (PTP1B): A Potential Target for Alzheimer's Therapy? Front Aging Neurosci 2017; 9:7. [PMID: 28197094 PMCID: PMC5281585 DOI: 10.3389/fnagi.2017.00007] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/12/2017] [Indexed: 01/21/2023] Open
Abstract
Despite significant advances in current understanding of mechanisms of pathogenesis in Alzheimer's disease (AD), attempts at drug development based on those discoveries have failed to translate into effective, disease-modifying therapies. AD is a complex and multifactorial disease comprising a range of aberrant cellular/molecular processes taking part in different cell types and brain regions. As a consequence, therapeutics for AD should be able to block or compensate multiple abnormal pathological events. Here, we examine recent evidence that inhibition of protein tyrosine phosphatase 1B (PTP1B) may represent a promising strategy to combat a variety of AD-related detrimental processes. Besides its well described role as a negative regulator of insulin and leptin signaling, PTB1B recently emerged as a modulator of various other processes in the central nervous system (CNS) that are also implicated in AD. These include signaling pathways germane to learning and memory, regulation of synapse dynamics, endoplasmic reticulum (ER) stress and microglia-mediated neuroinflammation. We propose that PTP1B inhibition may represent an attractive and yet unexplored therapeutic approach to correct aberrant signaling pathways linked to AD.
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Affiliation(s)
- Marcelo N N Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Natalia M Lyra E Silva
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's UniversityKingston, ON, Canada
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487
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Nitkiewicz J, Borjabad A, Morgello S, Murray J, Chao W, Emdad L, Fisher PB, Potash MJ, Volsky DJ. HIV induces expression of complement component C3 in astrocytes by NF-κB-dependent activation of interleukin-6 synthesis. J Neuroinflammation 2017; 14:23. [PMID: 28122624 PMCID: PMC5267445 DOI: 10.1186/s12974-017-0794-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/10/2017] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Abnormal activation of the complement system contributes to some central nervous system diseases but the role of complement in HIV-associated neurocognitive disorder (HAND) is unclear. METHODS We used real-time PCR and immunohistochemistry to detect complement expression in postmortem brain tissue from HAND patients and controls. To further investigate the basis for viral induction of gene expression in the brain, we studied the effect of HIV on C3 expression by astrocytes, innate immune effector cells, and targets of HIV. Human fetal astrocytes (HFA) were infected with HIV in culture and cellular pathways and factors involved in signaling to C3 expression were elucidated using pharmacological pathway inhibitors, antisense RNA, promoter mutational analysis, and fluorescence microscopy. RESULTS We found significantly increased expression of complement components including C3 in brain tissues from patients with HAND and C3 was identified by immunocytochemistry in astrocytes and neurons. Exposure of HFA to HIV in culture-induced C3 promoter activity, mRNA expression, and protein production. Use of pharmacological inhibitors indicated that induction of C3 expression by HIV requires NF-κB and protein kinase signaling. The relevance of NF-κB regulation to C3 induction was confirmed through detection of NF-κB translocation into nuclei and inhibition through overexpression of the physiological NF-κB inhibitor, I-κBα. C3 promoter mutation analysis revealed that the NF-κB and SP binding sites are dispensable for the induction by HIV, while the proximal IL-1β/IL-6 responsive element is essential. HIV-treated HFA secreted IL-6, exogenous IL-6 activated the C3 promoter, and anti-IL-6 antibodies blocked HIV activation of the C3 promoter. The activation of IL-6 transcription by HIV was dependent upon an NF-κB element within the IL-6 promoter. CONCLUSIONS These results suggest that HIV activates C3 expression in primary astrocytes indirectly, through NF-κB-dependent induction of IL-6, which in turn activates the C3 promoter. HIV induction of C3 and IL-6 in astrocytes may contribute to HIV-mediated inflammation in the brain and cognitive dysfunction.
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Affiliation(s)
- Jadwiga Nitkiewicz
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
- Present Address: PSI-CRO, Wisniowy Business Park C, 1 Sierpnia 6A, 02-134 Warsaw, Poland
| | - Alejandra Borjabad
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
| | - Susan Morgello
- Manhattan HIV Brain Bank, Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
| | - Jacinta Murray
- Manhattan HIV Brain Bank, Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
| | - Wei Chao
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
| | - Luni Emdad
- Department of Human and Molecular Genetics, VCU Massey Cancer Center, School of Medicine, VCU Institute of Molecular Medicine, Virginia Commonwealth UniversitySchool of Medicine, Richmond, 23298 VA USA
| | - Paul B. Fisher
- Department of Human and Molecular Genetics, VCU Massey Cancer Center, School of Medicine, VCU Institute of Molecular Medicine, Virginia Commonwealth UniversitySchool of Medicine, Richmond, 23298 VA USA
| | - Mary Jane Potash
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
| | - David J. Volsky
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, 10029 NY USA
- Department of Medicine, Division of Infectious Diseases, 1468 Madison Avenue, Annenberg Building, 21st Floor, Room 42, New York, 10029 NY USA
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488
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Klein RS, Garber C, Howard N. Infectious immunity in the central nervous system and brain function. Nat Immunol 2017; 18:132-141. [PMID: 28092376 DOI: 10.1038/ni.3656] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/02/2016] [Indexed: 11/09/2022]
Abstract
Inflammation is emerging as a critical mechanism underlying neurological disorders of various etiologies, yet its role in altering brain function as a consequence of neuroinfectious disease remains unclear. Although acute alterations in mental status due to inflammation are a hallmark of central nervous system (CNS) infections with neurotropic pathogens, post-infectious neurologic dysfunction has traditionally been attributed to irreversible damage caused by the pathogens themselves. More recently, studies indicate that pathogen eradication within the CNS may require immune responses that interfere with neural cell function and communication without affecting their survival. In this Review we explore inflammatory processes underlying neurological impairments caused by CNS infection and discuss their potential links to established mechanisms of psychiatric and neurodegenerative diseases.
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Affiliation(s)
- Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Charise Garber
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicole Howard
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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489
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Presumey J, Bialas AR, Carroll MC. Complement System in Neural Synapse Elimination in Development and Disease. Adv Immunol 2017; 135:53-79. [DOI: 10.1016/bs.ai.2017.06.004] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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490
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Ardura-Fabregat A, Boddeke EWGM, Boza-Serrano A, Brioschi S, Castro-Gomez S, Ceyzériat K, Dansokho C, Dierkes T, Gelders G, Heneka MT, Hoeijmakers L, Hoffmann A, Iaccarino L, Jahnert S, Kuhbandner K, Landreth G, Lonnemann N, Löschmann PA, McManus RM, Paulus A, Reemst K, Sanchez-Caro JM, Tiberi A, Van der Perren A, Vautheny A, Venegas C, Webers A, Weydt P, Wijasa TS, Xiang X, Yang Y. Targeting Neuroinflammation to Treat Alzheimer's Disease. CNS Drugs 2017; 31:1057-1082. [PMID: 29260466 PMCID: PMC5747579 DOI: 10.1007/s40263-017-0483-3] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Over the past few decades, research on Alzheimer's disease (AD) has focused on pathomechanisms linked to two of the major pathological hallmarks of extracellular deposition of beta-amyloid peptides and intra-neuronal formation of neurofibrils. Recently, a third disease component, the neuroinflammatory reaction mediated by cerebral innate immune cells, has entered the spotlight, prompted by findings from genetic, pre-clinical, and clinical studies. Various proteins that arise during neurodegeneration, including beta-amyloid, tau, heat shock proteins, and chromogranin, among others, act as danger-associated molecular patterns, that-upon engagement of pattern recognition receptors-induce inflammatory signaling pathways and ultimately lead to the production and release of immune mediators. These may have beneficial effects but ultimately compromise neuronal function and cause cell death. The current review, assembled by participants of the Chiclana Summer School on Neuroinflammation 2016, provides an overview of our current understanding of AD-related immune processes. We describe the principal cellular and molecular players in inflammation as they pertain to AD, examine modifying factors, and discuss potential future therapeutic targets.
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Affiliation(s)
- A. Ardura-Fabregat
- grid.5963.9Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany
| | - E. W. G. M. Boddeke
- 0000 0004 0407 1981grid.4830.fDepartment of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A. Boza-Serrano
- 0000 0001 0930 2361grid.4514.4Experimental Neuroinflammation Laboratory, Department of Experimental Medical Sciences, Biomedical Centrum (BMC), Lund University, Lund, Sweden
| | - S. Brioschi
- grid.5963.9Department of Psychiatry and Psychotherapy, Medical Center University of Freiburg, Faculty of Medicine University of Freiburg, Freiburg, Germany
| | - S. Castro-Gomez
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - K. Ceyzériat
- grid.457334.2Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut de biologie François Jacob, MIRCen, 92260 Fontenay-aux-Roses, France ,0000 0001 2171 2558grid.5842.bNeurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, UMR 9199, F-92260 Fontenay-aux-Roses, France
| | - C. Dansokho
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - T. Dierkes
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany ,0000 0000 8786 803Xgrid.15090.3dBiomedical Centre, Institute of Innate Immunity, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - G. Gelders
- 0000 0001 0668 7884grid.5596.fDepartment of Neurosciences, Laboratory for Neurobiology and Gene Therapy, KU Leuven, Leuven, Belgium
| | - Michael T. Heneka
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany ,0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - L. Hoeijmakers
- 0000000084992262grid.7177.6Center for Neuroscience (SILS-CNS), Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - A. Hoffmann
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - L. Iaccarino
- grid.15496.3fVita-Salute San Raffaele University, Milan, Italy ,0000000417581884grid.18887.3eIn Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - S. Jahnert
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - K. Kuhbandner
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - G. Landreth
- 0000 0001 2287 3919grid.257413.6Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202 USA
| | - N. Lonnemann
- 0000 0001 1090 0254grid.6738.aDepartment of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | | | - R. M. McManus
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - A. Paulus
- 0000 0001 0930 2361grid.4514.4Experimental Neuroinflammation Laboratory, Department of Experimental Medical Sciences, Biomedical Centrum (BMC), Lund University, Lund, Sweden
| | - K. Reemst
- 0000000084992262grid.7177.6Center for Neuroscience (SILS-CNS), Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - J. M. Sanchez-Caro
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - A. Tiberi
- grid.6093.cBio@SNS Laboratory, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - A. Van der Perren
- 0000 0001 0668 7884grid.5596.fDepartment of Neurosciences, Laboratory for Neurobiology and Gene Therapy, KU Leuven, Leuven, Belgium
| | - A. Vautheny
- grid.457334.2Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut de biologie François Jacob, MIRCen, 92260 Fontenay-aux-Roses, France ,0000 0001 2171 2558grid.5842.bNeurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, UMR 9199, F-92260 Fontenay-aux-Roses, France
| | - C. Venegas
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - A. Webers
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - P. Weydt
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - T. S. Wijasa
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - X. Xiang
- 0000 0004 1936 973Xgrid.5252.0Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, Germany ,0000 0004 1936 973Xgrid.5252.0Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University, Munich, 82152 Munich, Germany
| | - Y. Yang
- 0000 0001 0930 2361grid.4514.4Experimental Neuroinflammation Laboratory, Department of Experimental Medical Sciences, Biomedical Centrum (BMC), Lund University, Lund, Sweden
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491
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Davies DS, Ma J, Jegathees T, Goldsbury C. Microglia show altered morphology and reduced arborization in human brain during aging and Alzheimer's disease. Brain Pathol 2016; 27:795-808. [PMID: 27862631 DOI: 10.1111/bpa.12456] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/10/2016] [Indexed: 12/12/2022] Open
Abstract
Changes in microglia function are involved in Alzheimer's disease (AD) for which ageing is the major risk factor. We evaluated microglial cell process morphologies and their gray matter coverage (arborized area) during ageing and in the presence and absence of AD pathology in autopsied human neocortex. Microglial cell processes were reduced in length, showed less branching and reduced arborized area with aging (case range 52-98 years). This occurred during normal ageing and without microglia dystrophy or changes in cell density. There was a larger reduction in process length and arborized area in AD compared to aged-matched control microglia. In AD cases, on average, 49%-64% of microglia had discontinuous and/or punctate Iba1 labeled processes instead of continuous Iba1 distribution. Up to 16% of aged-matched control microglia displayed discontinuous or punctate features. There was no change in the density of microglial cell bodies in gray matter during ageing or AD. This demonstrates that human microglia show progressive cell process retraction without cell loss during ageing. Additional changes in microglia occur with AD including Iba1 protein puncta and discontinuity. We suggest that reduced microglial arborized area may be an aging-related correlate of AD in humans. These variations in microglial cells during ageing and in AD could reflect changes in neural-glial interactions which are emerging as key to mechanisms involved in ageing and neurodegenerative disease.
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Affiliation(s)
- Danielle S Davies
- Brain and Mind Centre, The University of Sydney, New South Wales, Australia.,Discipline of Anatomy and Histology, School of Medical Sciences, The University of Sydney, New South Wales, Australia
| | - Jolande Ma
- Brain and Mind Centre, The University of Sydney, New South Wales, Australia.,Discipline of Anatomy and Histology, School of Medical Sciences, The University of Sydney, New South Wales, Australia
| | | | - Claire Goldsbury
- Brain and Mind Centre, The University of Sydney, New South Wales, Australia.,Discipline of Anatomy and Histology, School of Medical Sciences, The University of Sydney, New South Wales, Australia
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492
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Microglial Dysregulation in OCD, Tourette Syndrome, and PANDAS. J Immunol Res 2016; 2016:8606057. [PMID: 28053994 PMCID: PMC5174185 DOI: 10.1155/2016/8606057] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/15/2016] [Indexed: 02/07/2023] Open
Abstract
There is accumulating evidence that immune dysregulation contributes to the pathophysiology of obsessive-compulsive disorder (OCD), Tourette syndrome, and Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS). The mechanistic details of this pathophysiology, however, remain unclear. Here we focus on one particular component of the immune system: microglia, the brain's resident immune cells. The role of microglia in neurodegenerative diseases has been understood in terms of classic, inflammatory activation, which may be both a consequence and a cause of neuronal damage. In OCD and Tourette syndrome, which are not characterized by frank neural degeneration, the potential role of microglial dysregulation is much less clear. Here we review the evidence for a neuroinflammatory etiology and microglial dysregulation in OCD, Tourette syndrome, and PANDAS. We also explore new hypotheses as to the potential contributions of microglial abnormalities to pathophysiology, beyond neuroinflammation, including failures in neuroprotection, lack of support for neuronal survival, and abnormalities in synaptic pruning. Recent advances in neuroimaging and animal model work are creating new opportunities to elucidate these issues.
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493
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Stower H, Bondar T, Farrell A, Basson M, Levinson R, Borowski C, Carmona J, Benedetti B. Notable advances 2016. Nat Med 2016; 22:1374-1376. [PMID: 27923031 DOI: 10.1038/nm1216-1374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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494
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Stogsdill JA, Eroglu C. The interplay between neurons and glia in synapse development and plasticity. Curr Opin Neurobiol 2016; 42:1-8. [PMID: 27788368 DOI: 10.1016/j.conb.2016.09.016] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/26/2016] [Indexed: 12/21/2022]
Abstract
In the brain, the formation of complex neuronal networks amenable to experience-dependent remodeling is complicated by the diversity of neurons and synapse types. The establishment of a functional brain depends not only on neurons, but also non-neuronal glial cells. Glia are in continuous bi-directional communication with neurons to direct the formation and refinement of synaptic connectivity. This article reviews important findings, which uncovered cellular and molecular aspects of the neuron-glia cross-talk that govern the formation and remodeling of synapses and circuits. In vivo evidence demonstrating the critical interplay between neurons and glia will be the major focus. Additional attention will be given to how aberrant communication between neurons and glia may contribute to neural pathologies.
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Affiliation(s)
- Jeff A Stogsdill
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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495
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Oosterhof N, Holtman IR, Kuil LE, van der Linde HC, Boddeke EWGM, Eggen BJL, van Ham TJ. Identification of a conserved and acute neurodegeneration-specific microglial transcriptome in the zebrafish. Glia 2016; 65:138-149. [PMID: 27757989 PMCID: PMC5215681 DOI: 10.1002/glia.23083] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/21/2016] [Accepted: 09/28/2016] [Indexed: 12/29/2022]
Abstract
Microglia are brain resident macrophages important for brain development, connectivity, homeostasis and disease. However, it is still largely unclear how microglia functions and their identity are regulated at the molecular level. Although recent transcriptomic studies have identified genes specifically expressed in microglia, the function of most of these genes in microglia is still unknown. Here, we performed RNA sequencing on microglia acutely isolated from healthy and neurodegenerative zebrafish brains. We found that a large fraction of the mouse microglial signature is conserved in the zebrafish, corroborating the use of zebrafish to help understand microglial genetics in mammals in addition to studying basic microglia biology. Second, our transcriptome analysis of microglia following neuronal ablation suggested primarily a proliferative response of microglia, which we confirmed by immunohistochemistry and in vivo imaging. Together with the recent improvements in genome editing technology in zebrafish, these data offer opportunities to facilitate functional genetic research on microglia in vivo in the healthy as well as in the diseased brain. GLIA 2016;65:138–149
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Affiliation(s)
- Nynke Oosterhof
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
| | - Inge R Holtman
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 971 3, AV, Groningen, The Netherlands
| | - Laura E Kuil
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
| | - Herma C van der Linde
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
| | - Erik W G M Boddeke
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 971 3, AV, Groningen, The Netherlands
| | - Bart J L Eggen
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 971 3, AV, Groningen, The Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
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496
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Terni B, López-Murcia FJ, Llobet A. Role of neuron-glia interactions in developmental synapse elimination. Brain Res Bull 2016; 129:74-81. [PMID: 27601093 DOI: 10.1016/j.brainresbull.2016.08.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/19/2016] [Accepted: 08/31/2016] [Indexed: 11/16/2022]
Abstract
During the embryonic development of the nervous system there is a massive formation of synapses. However, the exuberant connectivity present after birth must be pruned during postnatal growth to optimize the function of neuronal circuits. Whilst glial cells play a fundamental role in the formation of early synaptic contacts, their contribution to developmental modifications of established synapses is not well understood. The present review aims to highlight the various roles of glia in the developmental refinement of embryonic synaptic connectivity. We summarize recent evidences linking secretory abilities of glial cells to the disassembly of synaptic contacts that are complementary of a well-established phagocytic role. Considering a theoretical framework, it is discussed how release of glial molecules could be relevant to the developmental refinement of synaptic connectivity. Finally, we propose a three-stage model of synapse elimination in which neurons and glia are functionally associated to timely eliminate synapses.
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Affiliation(s)
- Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Francisco José López-Murcia
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain.
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497
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Abstract
Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal lobar dementia are among the most pressing problems of developed societies with aging populations. Neurons carry out essential functions such as signal transmission and network integration in the central nervous system and are the main targets of neurodegenerative disease. In this Review, I address how the neuron's environment also contributes to neurodegeneration. Maintaining an optimal milieu for neuronal function rests with supportive cells termed glia and the blood-brain barrier. Accumulating evidence suggests that neurodegeneration occurs in part because the environment is affected during disease in a cascade of processes collectively termed neuroinflammation. These observations indicate that therapies targeting glial cells might provide benefit for those afflicted by neurodegenerative disorders.
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498
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Novel allele-dependent role for APOE in controlling the rate of synapse pruning by astrocytes. Proc Natl Acad Sci U S A 2016; 113:10186-91. [PMID: 27559087 DOI: 10.1073/pnas.1609896113] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The strongest genetic risk factor influencing susceptibility to late-onset Alzheimer's disease (AD) is apolipoprotein E (APOE) genotype. APOE has three common isoforms in humans, E2, E3, and E4. The presence of two copies of the E4 allele increases risk by ∼12-fold whereas E2 allele is associated with an ∼twofold decreased risk for AD. These data put APOE central to AD pathophysiology, but it is not yet clear how APOE alleles modify AD risk. Recently we found that astrocytes, a major central nervous system cell type that produces APOE, are highly phagocytic and participate in normal synapse pruning and turnover. Here, we report a novel role for APOE in controlling the phagocytic capacity of astrocytes that is highly dependent on APOE isoform. APOE2 enhances the rate of phagocytosis of synapses by astrocytes, whereas APO4 decreases it. We also found that the amount of C1q protein accumulation in hippocampus, which may represent the accumulation of senescent synapses with enhanced vulnerability to complement-mediated degeneration, is highly dependent on APOE alleles: C1q accumulation was significantly reduced in APOE2 knock-in (KI) animals and was significantly increased in APOE4 KI animals compared with APOE3 KI animals. These studies reveal a novel allele-dependent role for APOE in regulating the rate of synapse pruning by astrocytes. They also suggest the hypothesis that AD susceptibility of APOE4 may originate in part from defective phagocytic capacity of astrocytes which accelerates the rate of accumulation of C1q-coated senescent synapses, enhancing synaptic vulnerability to classical-complement-cascade mediated neurodegeneration.
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499
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Amick J, Roczniak-Ferguson A, Ferguson SM. C9orf72 binds SMCR8, localizes to lysosomes, and regulates mTORC1 signaling. Mol Biol Cell 2016; 27:3040-3051. [PMID: 27559131 PMCID: PMC5063613 DOI: 10.1091/mbc.e16-01-0003] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 08/19/2016] [Indexed: 12/18/2022] Open
Abstract
C9orf72 interacts strongly with SMCR8 and depends on this interaction for its stability. Lysosomes are major sites of C9orf72 subcellular localization, and abnormal lysosome morphology is seen in its absence. Defects are found in the regulation of the lysosome-localized mTORC1 signaling pathway in C9orf72 KO cells. Hexanucleotide expansion in an intron of the C9orf72 gene causes amyotrophic lateral sclerosis and frontotemporal dementia. However, beyond bioinformatics predictions that suggested structural similarity to folliculin, the Birt-Hogg-Dubé syndrome tumor suppressor, little is known about the normal functions of the C9orf72 protein. To address this problem, we used genome-editing strategies to investigate C9orf72 interactions, subcellular localization, and knockout (KO) phenotypes. We found that C9orf72 robustly interacts with SMCR8 (a protein of previously unknown function). We also observed that C9orf72 localizes to lysosomes and that such localization is negatively regulated by amino acid availability. Analysis of C9orf72 KO, SMCR8 KO, and double-KO cell lines revealed phenotypes that are consistent with a function for C9orf72 at lysosomes. These include abnormally swollen lysosomes in the absence of C9orf72 and impaired responses of mTORC1 signaling to changes in amino acid availability (a lysosome-dependent process) after depletion of either C9orf72 or SMCR8. Collectively these results identify strong physical and functional interactions between C9orf72 and SMCR8 and support a lysosomal site of action for this protein complex.
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Affiliation(s)
- Joseph Amick
- Department of Cell Biology and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Agnes Roczniak-Ferguson
- Department of Cell Biology and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Shawn M Ferguson
- Department of Cell Biology and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510
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500
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Abstract
Neuroimmunologists seek to understand the interactions between the central nervous system (CNS) and the immune system, both under homeostatic conditions and in diseases. Unanswered questions include those relating to the diversity and specificity of the meningeal T cell repertoire; the routes taken by immune cells that patrol the meninges under healthy conditions and invade the parenchyma during pathology; the opposing effects (beneficial or detrimental) of these cells on CNS function; the role of immune cells after CNS injury; and the evolutionary link between the two systems, resulting in their tight interaction and interdependence. This Review summarizes the current standing of and challenging questions related to interactions between adaptive immunity and the CNS and considers the possible directions in which these aspects of neuroimmunology will be heading over the next decade.
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Affiliation(s)
- Jonathan Kipnis
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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