Publications by authors named "Jack P Antel"

129 Publications

COVID-19 and disease-modifying therapies in patients with demyelinating diseases of the central nervous system: A systematic review.

Mult Scler Relat Disord 2021 Jan 29;50:102800. Epub 2021 Jan 29.

Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.

Introduction: The Coronavirus disease-19 (COVID-19) pandemic continues to expand across the world. This pandemic has had a significant impact on patients with chronic diseases. Among patients with demyelinating diseases of the central nervous system (CNS), such as Multiple Sclerosis (MS) or Neuromyelitis Optica Spectrum Disorder (NMOSD), concerns remain about the potential impact of COVID-19 on these patients given their treatment with immunosuppressive or immunomodulatory therapies. In this study, we review the existing literature investigating the impact of disease-modifying therapies(DMT) on COVID-19 risks in this group of patients.

Method: For this systematic review, we searched PubMed from January 1, 2020, to December 3, 2020. The following keywords were used: "COVID-19" AND "Multiple Sclerosis" OR "Neuromyelitis Optica." Articles evaluating COVID-19 in patients with demyelinating diseases of CNS were included. This study evaluates the different aspects of the DMTs in these patients during the COVID-19 era.

Results And Conclusion: A total of 262 articles were found. After eliminating duplicates and unrelated research papers, a total of 84 articles met the final inclusion criteria in our study. Overall, the experiences of 2493 MS patients and 37 NMOSD patients with COVID-19 were included in this review. Among them, 46(1.8%) MS patients died(the global death-to-case ratio of Covid-19 was reported about 2.1%). Among DMTs, Rituximab had the highest mortality rate (4%). Despite controversies, especially concerning anti-CD20 monoclonal antibody therapies, a relation between DMT-use and COVID-19 disease- course was not found in many studies. This observation reinforces the recommendation of not stopping current DMTs. Other variables such as age, higher expanded disability status scale (EDSS) scores, cardiac comorbidities, and obesity were independent risk factors for severe COVID-19. Despite the risks of infection, most patients were willing to continue their DMT during the pandemic because of more significant concern about the risk of relapse or worsening MS symptoms. After the infection, an immune response's attenuation was seen in the patients on Fingolimod and anti-CD20 monoclonal antibodies. This may be a critical finding in future vaccinations.
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http://dx.doi.org/10.1016/j.msard.2021.102800DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7845520PMC
January 2021

Age-related injury responses of human oligodendrocytes to metabolic insults: link to BCL-2 and autophagy pathways.

Commun Biol 2021 Jan 4;4(1):20. Epub 2021 Jan 4.

Neuroimmunology Unit, Montreal Neurological Institute and Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.

Myelin destruction and oligodendrocyte (OL) death consequent to metabolic stress is a feature of CNS disorders across the age spectrum. Using cells derived from surgically resected tissue, we demonstrate that young (
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http://dx.doi.org/10.1038/s42003-020-01557-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782481PMC
January 2021

The Identity of Human Tissue-Emigrant CD8 T Cells.

Cell 2020 Dec 10;183(7):1946-1961.e15. Epub 2020 Dec 10.

Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Electronic address:

Lymphocyte migration is essential for adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies have been restricted to immunological analyses of blood and various tissues. To address this knowledge gap, we used an integrated approach to characterize tissue-emigrant lineages in thoracic duct lymph (TDL). The most prevalent immune cells in human and non-human primate efferent lymph were T cells. Cytolytic CD8 T cell subsets with effector-like epigenetic and transcriptional signatures were clonotypically skewed and selectively confined to the intravascular circulation, whereas non-cytolytic CD8 T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Moreover, these anatomically distinct gene expression profiles were recapitulated within individual clonotypes, suggesting parallel differentiation programs independent of the expressed antigen receptor. Our collective dataset provides an atlas of the migratory immune system and defines the nature of tissue-emigrant CD8 T cells that recirculate via TDL.
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http://dx.doi.org/10.1016/j.cell.2020.11.019DOI Listing
December 2020

Multiple sclerosis iPS-derived oligodendroglia conserve their properties to functionally interact with axons and glia in vivo.

Sci Adv 2020 Dec 4;6(49). Epub 2020 Dec 4.

INSERM, U1127, F-75013 Paris, France.

Remyelination failure in multiple sclerosis (MS) is associated with a migration/differentiation block of oligodendroglia. The reason for this block is highly debated. It could result from disease-related extrinsic or intrinsic regulators in oligodendroglial biology. To avoid confounding immune-mediated extrinsic effect, we used an immune-deficient mouse model to compare induced pluripotent stem cell-derived oligodendroglia from MS and healthy donors following engraftment in the developing CNS. We show that the MS-progeny behaves and differentiates into oligodendrocytes to the same extent as controls. They generate equal amounts of myelin, with bona fide nodes of Ranvier, and promote equal restoration of their host slow conduction. MS-progeny expressed oligodendrocyte- and astrocyte-specific connexins and established functional connections with donor and host glia. Thus, MS oligodendroglia, regardless of major immune manipulators, are intrinsically capable of myelination and making functional axo-glia/glia-glia connections, reinforcing the view that the MS oligodendrocyte differentiation block is not from major intrinsic oligodendroglial deficits.
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http://dx.doi.org/10.1126/sciadv.abc6983DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821889PMC
December 2020

Mitochondrial dynamics and bioenergetics regulated by netrin-1 in oligodendrocytes.

Glia 2021 Feb 10;69(2):392-412. Epub 2020 Sep 10.

Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.

Mitochondria are dynamic organelles that produce energy and molecular precursors that are essential for myelin synthesis. Unlike in neurons, mitochondria in oligodendrocytes increase intracellular movement in response to glutamatergic activation and are more susceptible to oxidative stress than in astrocytes or microglia. The signaling pathways that regulate these cell type-specific mitochondrial responses in oligodendrocytes are not understood. Here, we visualized mitochondria migrating through thin cytoplasmic channels crossing myelin basic protein-positive compacted membranes and localized within paranodal loop cytoplasm. We hypothesized that local extracellular enrichment of netrin-1 might regulate the recruitment and function of paranodal proteins and organelles, including mitochondria. We identified rapid recruitment of mitochondria and paranodal proteins, including neurofascin 155 (NF155) and the netrin receptor deleted in colorectal carcinoma (DCC), to sites of contact between oligodendrocytes and netrin-1-coated microbeads in vitro. We provide evidence that Src-family kinase activation and Rho-associated protein kinase (ROCK) inhibition downstream of netrin-1 induces mitochondrial elongation, hyperpolarization of the mitochondrial inner membrane, and increases glycolysis. Our findings identify a signaling mechanism in oligodendrocytes that is sufficient to locally recruit paranodal proteins and regulate the subcellular localization, morphology, and function of mitochondria.
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http://dx.doi.org/10.1002/glia.23905DOI Listing
February 2021

Neurological complications of coronavirus infection; a comparative review and lessons learned during the COVID-19 pandemic.

J Neurol Sci 2020 10 7;417:117085. Epub 2020 Aug 7.

Department of Neurological Surgery, Keck School of Medicine, University of Southern California (USC), Los Angeles, CA, USA. Electronic address:

Introduction: Coronavirus disease-19 (COVID-19) pandemic continues to grow all over the world. Several studies have been performed, focusing on understanding the acute respiratory syndrome and treatment strategies. However, there is growing evidence indicating neurological manifestations occur in patients with COVID-19. Similarly, the other coronaviruses (CoV) epidemics; severe acute respiratory syndrome (SARS-CoV-1) and Middle East respiratory syndrome (MERS-CoV) have been associated with neurological complications.

Methods: This systematic review serves to summarize available information regarding the potential effects of different types of CoV on the nervous system and describes the range of clinical neurological complications that have been reported thus far in COVID-19.

Results: Two hundred and twenty-five studies on CoV infections associated neurological manifestations in human were reviewed. Of those, 208 articles were pertinent to COVID-19. The most common neurological complaints in COVID-19 were anosmia, ageusia, and headache, but more serious complications, such as stroke, impairment of consciousness, seizures, and encephalopathy, have also been reported.

Conclusion: There are several similarities between neurological complications after SARS-CoV-1, MERS-CoV and COVID-19, however, the scope of the epidemics and number of patients are very different. Reports on the neurological complications after and during COVID-19 are growing on a daily basis. Accordingly, comprehensive knowledge of these complications will help health care providers to be attentive to these complications and diagnose and treat them timely.
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http://dx.doi.org/10.1016/j.jns.2020.117085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413162PMC
October 2020

RNA-binding protein altered expression and mislocalization in MS.

Neurol Neuroimmunol Neuroinflamm 2020 05 26;7(3). Epub 2020 Mar 26.

From the Department of Neurology (K.M., Y.S., G.G., R.P.R.) and Department of Pathology (P.P.), University of Chicago Medical Center, IL; Neuroimmunology Research Laboratory (P.L., S.Z., A.P.), Centre du Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), QC, Canada; and Neuroimmunology Unit (F.P., Q.-L.C., J.P.A.), Montreal Neurological Institute, McGill University, QC, Canada.

Objective: To determine whether there are nuclear depletion and cellular mislocalization of RNA-binding proteins (RBPs) transactivation response DNA-binding protein of 43 kDa (TDP-43), fused in sarcoma (FUS), and polypyrimidine tract-binding protein (PTB) in MS, as is the case in amyotrophic lateral sclerosis (ALS) and oligodendrocytes infected with Theiler murine encephalomyelitis virus (TMEV), we examined MS lesions and in vitro cultured primary human brain-derived oligodendrocytes.

Methods: Nuclear depletion and mislocalization of TDP-43, FUS, and PTB are thought to contribute to the pathogenesis of ALS and TMEV demyelination. The latter findings prompted us to investigate these RBPs in the demyelinated lesions of MS and in in vitro cultured human brain-derived oligodendrocytes under metabolic stress conditions.

Results: We found (1) mislocalized TDP-43 in oligodendrocytes in active lesions in some patients with MS; (2) decreased PTB1 expression in oligodendrocytes in mixed active/inactive demyelinating lesions; (3) decreased nuclear expression of PTB2 in neurons in cortical demyelinating lesions; and (4) nuclear depletion of TDP-43 in oligodendrocytes under metabolic stress induced by low glucose/low nutrient conditions compared with optimal culture conditions.

Conclusion: TDP-43 has been found to have a key role in oligodendrocyte function and viability, whereas PTB is important in neuronal differentiation, suggesting that altered expression and mislocalization of these RBPs in MS lesions may contribute to the pathogenesis of demyelination and neurodegeneration. Our findings also identify nucleocytoplasmic transport as a target for treatment.
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http://dx.doi.org/10.1212/NXI.0000000000000704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176246PMC
May 2020

MAFG-driven astrocytes promote CNS inflammation.

Nature 2020 02 12;578(7796):593-599. Epub 2020 Feb 12.

Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.

Multiple sclerosis is a chronic inflammatory disease of the CNS. Astrocytes contribute to the pathogenesis of multiple sclerosis, but little is known about the heterogeneity of astrocytes and its regulation. Here we report the analysis of astrocytes in multiple sclerosis and its preclinical model experimental autoimmune encephalomyelitis (EAE) by single-cell RNA sequencing in combination with cell-specific Ribotag RNA profiling, assay for transposase-accessible chromatin with sequencing (ATAC-seq), chromatin immunoprecipitation with sequencing (ChIP-seq), genome-wide analysis of DNA methylation and in vivo CRISPR-Cas9-based genetic perturbations. We identified astrocytes in EAE and multiple sclerosis that were characterized by decreased expression of NRF2 and increased expression of MAFG, which cooperates with MAT2α to promote DNA methylation and represses antioxidant and anti-inflammatory transcriptional programs. Granulocyte-macrophage colony-stimulating factor (GM-CSF) signalling in astrocytes drives the expression of MAFG and MAT2α and pro-inflammatory transcriptional modules, contributing to CNS pathology in EAE and, potentially, multiple sclerosis. Our results identify candidate therapeutic targets in multiple sclerosis.
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http://dx.doi.org/10.1038/s41586-020-1999-0DOI Listing
February 2020

Developmental trajectory of oligodendrocyte progenitor cells in the human brain revealed by single cell RNA sequencing.

Glia 2020 06 20;68(6):1291-1303. Epub 2020 Jan 20.

Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.

Characterizing the developmental trajectory of oligodendrocyte progenitor cells (OPC) is of great interest given the importance of these cells in the remyelination process. However, studies of human OPC development remain limited by the availability of whole cell samples and material that encompasses a wide age range, including time of peak myelination. In this study, we apply single cell RNA sequencing to viable whole cells across the age span and link transcriptomic signatures of oligodendrocyte-lineage cells with stage-specific functional properties. Cells were isolated from surgical tissue samples of second-trimester fetal, 2-year-old pediatric, 13-year-old adolescent, and adult donors by mechanical and enzymatic digestion, followed by percoll gradient centrifugation. Gene expression was analyzed using droplet-based RNA sequencing (10X Chromium). Louvain clustering analysis identified three distinct cellular subpopulations based on 5,613 genes, comprised of an early OPC (e-OPC) group, a late OPC group (l-OPC), and a mature OL (MOL) group. Gene ontology terms enriched for e-OPCs included cell cycle and development, for l-OPCs included extracellular matrix and cell adhesion, and for MOLs included myelination and cytoskeleton. The e-OPCs were mostly confined to the premyelinating fetal group, and the l-OPCs were most highly represented in the pediatric age group, corresponding to the peak age of myelination. Cells expressing a signature characteristic of l-OPCs were identified in the adult brain in situ using RNAScope. These findings highlight the transcriptomic variability in OL-lineage cells before, during, and after peak myelination and contribute to identifying novel pathways required to achieve remyelination.
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http://dx.doi.org/10.1002/glia.23777DOI Listing
June 2020

Glial Cells as Regulators of Neuroimmune Interactions in the Central Nervous System.

J Immunol 2020 01;204(2):251-255

Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115; and.

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http://dx.doi.org/10.4049/jimmunol.1900908DOI Listing
January 2020

Metabolic Control of Astrocyte Pathogenic Activity via cPLA2-MAVS.

Cell 2019 12 5;179(7):1483-1498.e22. Epub 2019 Dec 5.

Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA. Electronic address:

Metabolism has been shown to control peripheral immunity, but little is known about its role in central nervous system (CNS) inflammation. Through a combination of proteomic, metabolomic, transcriptomic, and perturbation studies, we found that sphingolipid metabolism in astrocytes triggers the interaction of the C2 domain in cytosolic phospholipase A2 (cPLA2) with the CARD domain in mitochondrial antiviral signaling protein (MAVS), boosting NF-κB-driven transcriptional programs that promote CNS inflammation in experimental autoimmune encephalomyelitis (EAE) and, potentially, multiple sclerosis. cPLA2 recruitment to MAVS also disrupts MAVS-hexokinase 2 (HK2) interactions, decreasing HK enzymatic activity and the production of lactate involved in the metabolic support of neurons. Miglustat, a drug used to treat Gaucher and Niemann-Pick disease, suppresses astrocyte pathogenic activities and ameliorates EAE. Collectively, these findings define a novel immunometabolic mechanism that drives pro-inflammatory astrocyte activities, outlines a new role for MAVS in CNS inflammation, and identifies candidate targets for therapeutic intervention.
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http://dx.doi.org/10.1016/j.cell.2019.11.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936326PMC
December 2019

Species differences in immune-mediated CNS tissue injury and repair: A (neuro)inflammatory topic.

Glia 2020 04 14;68(4):811-829. Epub 2019 Nov 14.

Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec, Canada.

Cells of the adaptive and innate immune systems in the brain parenchyma and in the meningeal spaces contribute to physiologic functions and disease states in the central nervous system (CNS). Animal studies have demonstrated the involvement of immune constituents, along with major histocompatibility complex (MHC) molecules, in neural development and rare genetic disorders (e.g., colony stimulating factor 1 receptor [CSF1R] deficiency). Genome wide association studies suggest a comparable role of the immune system in humans. Although the CNS can be the target of primary autoimmune disorders, no current experimental model captures all of the features of the most common human disorder placed in this category, multiple sclerosis (MS). Such features include spontaneous onset, environmental contributions, and a recurrent/progressive disease course in a genetically predisposed host. Numerous therapeutic interventions related to antigen and cytokine specific therapies have demonstrated effectiveness in experimental autoimmune encephalomyelitis (EAE), the animal model used to define principles underlying immune-mediated mechanisms in MS. Despite the similarities in the two diseases, most treatments used to ameliorate EAE have failed to translate to the human disease. As directly demonstrated in animal models and implicated by correlative studies in humans, adaptive and innate immune constituents within the systemic compartment and resident in the CNS contribute to the disease course of neurodegenerative and neurobehavioral disorders. The expanding knowledge of the molecular properties of glial cells provides increasing insights into species related variables. These variables affect glial bidirectional interactions with the immune system as well as their own production of "immune molecules" that mediate tissue injury and repair.
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http://dx.doi.org/10.1002/glia.23746DOI Listing
April 2020

Astrocytes in the Pathogenesis of Multiple Sclerosis: An In Situ MicroRNA Study.

J Neuropathol Exp Neurol 2019 12;78(12):1130-1146

Department of Pathology, The Ottawa Hospital, University of Ottawa.

Astrocytes are increasingly recognized as active contributors to the disease process in multiple sclerosis (MS), rather than being merely reactive. We investigated the expression of a selected microRNA (miRNA) panel that could contribute both to the injury and to the recovery phases of the disease. Individual astrocytes were laser microdissected from brain sections. We then compared the miRNAs' expressions in MS and control brain samples at different lesional stages in white versus grey matter regions. In active MS lesions, we found upregulation of ischemia-related miRNAs in white but not grey matter, often with reversion to the normal state in inactive lesions. In contrast to our previous findings on MS macrophages, expression of 2 classical inflammatory-related miRNAs, miRNA-155 and miRNA-146a, was reduced in astrocytes from active and chronic active MS lesions in white and grey matter, suggesting a lesser direct pathogenetic role for these miRNAs in astrocytes. miRNAs within the categories regulating aquaporin4 (-100, -145, -320) and glutamate transport/apoptosis/neuroprotection (-124a, -181a, and -29a) showed some contrasting responses. The regional and lesion-stage differences of expression of these miRNAs indicate the remarkable ability of astrocytes to show a wide range of selective responses in the face of differing insults and phases of resolution.
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http://dx.doi.org/10.1093/jnen/nlz098DOI Listing
December 2019

T follicular helper cells in human efferent lymph retain lymphoid characteristics.

J Clin Invest 2019 07 2;129(8):3185-3200. Epub 2019 Jul 2.

Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

T follicular helper cells (Tfh), a subset of CD4+ T cells, provide requisite help to B cells in the germinal centers (GC) of lymphoid tissue. GC Tfh are identified by high expression of the chemokine receptor CXCR5 and the inhibitory molecule PD-1. Although more accessible, blood contains lower frequencies of CXCR5+ and PD-1+ cells that have been termed circulating Tfh (cTfh). However, it remains unclear whether GC Tfh exit lymphoid tissues and populate this cTfh pool. To examine exiting cells, we assessed the phenotype of Tfh present within the major conduit of efferent lymph from lymphoid tissues into blood, the human thoracic duct. Unlike what was found in blood, we consistently identified a CXCR5-bright PD-1-bright (CXCR5BrPD-1Br) Tfh population in thoracic duct lymph (TDL). These CXCR5BrPD-1Br TDL Tfh shared phenotypic and transcriptional similarities with GC Tfh. Moreover, components of the epigenetic profile of GC Tfh could be detected in CXCR5BrPD-1Br TDL Tfh and the transcriptional imprint of this epigenetic signature was enriched in an activated cTfh subset known to contain vaccine-responding cells. Together with data showing shared TCR sequences between the CXCR5BrPD-1Br TDL Tfh and cTfh, these studies identify a population in TDL as a circulatory intermediate connecting the biology of Tfh in blood to Tfh in lymphoid tissue.
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http://dx.doi.org/10.1172/JCI125628DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6668682PMC
July 2019

Distinct Function-Related Molecular Profile of Adult Human A2B5-Positive Pre-Oligodendrocytes Versus Mature Oligodendrocytes.

J Neuropathol Exp Neurol 2019 06;78(6):468-479

Neuroimmunology Unit, Montreal Neurological Institute, McGill University.

Remyelination in the human CNS is ascribed to progenitor cells rather than previously myelinating oligodendrocytes (OLs). The ganglioside-recognizing antibody A2B5 has been used to isolate putative progenitor cells, whose in vitro features resemble cells labeled as "pre-oligodendrocytes." Here, we compare the transcriptional profiles of adult human brain-derived A2B5 antibody-selected cells (A+) after initial isolation (day in vitro (DIV1)) and after DIV6, with nonselected (A-) cells (mature OLs), with regard to their differentiation state and functional properties. While a number of previously recognized progenitor associated genes, specifically PTPRZ1 and PDGFRα, were upregulated in the A2B5+ population, a number of such genes were comparably expressed in the mature OLs, as were mature myelin genes. Additional progenitor-related genes were upregulated in the A+ population. We show that A2B5+ cells have greater capacity to ensheath nanofibers, a model of myelination potential; consistent with this, ingenuity pathway analysis indicated that A+ cells had upregulated expression of genes within cell growth and cell signaling pathways. Differential expression of cell death/survival pathways complements previous functional studies showing their increased susceptibility to metabolic stress. At DIV6, we observed significantly fewer differentially expressed genes; suggestive of cell maturation occurring in vitro, indicating the complexity in comparing in vitro and in situ cell properties.
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http://dx.doi.org/10.1093/jnen/nlz026DOI Listing
June 2019

Deep learning for high-throughput quantification of oligodendrocyte ensheathment at single-cell resolution.

Commun Biol 2019 26;2:116. Epub 2019 Mar 26.

McGill Program in Neuroengineering, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, QC Canada.

High-throughput quantification of oligodendrocyte myelination is a challenge that, if addressed, would facilitate the development of therapeutics to promote myelin protection and repair. Here, we established a high-throughput method to assess oligodendrocyte ensheathment , combining nanofiber culture devices and automated imaging with a heuristic approach that informed the development of a deep learning analytic algorithm. The heuristic approach was developed by modeling general characteristics of oligodendrocyte ensheathments, while the deep learning neural network employed a UNet architecture and a single-cell training method to associate ensheathed segments with individual oligodendrocytes. Reliable extraction of multiple morphological parameters from individual cells, without heuristic approximations, allowed the UNet to match the accuracy of expert-human measurements. The capacity of this technology to perform multi-parametric analyses at the level of individual cells, while reducing manual labor and eliminating human variability, permits the detection of nuanced cellular differences to accelerate the discovery of new insights into oligodendrocyte physiology.
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http://dx.doi.org/10.1038/s42003-019-0356-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435748PMC
May 2020

Environmental Control of Astrocyte Pathogenic Activities in CNS Inflammation.

Cell 2019 01 17;176(3):581-596.e18. Epub 2019 Jan 17.

Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA. Electronic address:

Genome-wide studies have identified genetic variants linked to neurologic diseases. Environmental factors also play important roles, but no methods are available for their comprehensive investigation. We developed an approach that combines genomic data, screens in a novel zebrafish model, computational modeling, perturbation studies, and multiple sclerosis (MS) patient samples to evaluate the effects of environmental exposure on CNS inflammation. We found that the herbicide linuron amplifies astrocyte pro-inflammatory activities by activating signaling via sigma receptor 1, inositol-requiring enzyme-1α (IRE1α), and X-box binding protein 1 (XBP1). Indeed, astrocyte-specific shRNA- and CRISPR/Cas9-driven gene inactivation combined with RNA-seq, ATAC-seq, ChIP-seq, and study of patient samples suggest that IRE1α-XBP1 signaling promotes CNS inflammation in experimental autoimmune encephalomyelitis (EAE) and, potentially, MS. In summary, these studies define environmental mechanisms that control astrocyte pathogenic activities and establish a multidisciplinary approach for the systematic investigation of the effects of environmental exposure in neurologic disorders.
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http://dx.doi.org/10.1016/j.cell.2018.12.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6440749PMC
January 2019

Helper CD4 T cells expressing granzyme B cause glial fibrillary acidic protein fragmentation in astrocytes in an MHCII-independent manner.

Glia 2019 04 16;67(4):582-593. Epub 2018 Nov 16.

Department of Exercise Science, Department of Biology, PERFORM Centre, Concordia University, Montréal, Quebec, Canada.

During inflammatory processes of the central nervous system, helper T cells have the capacity to cross the blood-brain barrier and injure or kill neural cells through cytotoxic mechanisms. Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is part of the astrocyte cytoskeleton that can become fragmented in neuroinflammatory conditions. The mechanism of action by which helper T cells with cytotoxic properties injure astrocytes is not completely understood. Primary human astrocytes were obtained from fetal brain tissue. Human helper (CD4 ) T cells were isolated from peripheral blood mononuclear cells and activated with the superantigen staphylococcal enterotoxin E (SEE). Granzyme B was detected by enzyme linked immunosorbent assay and intracellular flow cytometry. GFAP fragmentation was monitored by western blotting. Cell death was monitored by lactic acid dehydrogenase release and terminal biotin-dUTP nick labeling (TUNEL). Astrocyte migration was monitored by scratch assay. Adult human oligodendrocytes were cultured with sublethally injured astrocytes to determine support function. Helper T cells activated with SEE expressed granzyme B but not perforin. Helper T cells released granzyme B upon contact with astrocytes and caused GFAP fragmentation in a caspase-dependent, MHCII-independent manner. Sublethally injured astrocytes were not apoptotic; however, their processes were thin and elongated, their migration was attenuated, and their ability to support oligodendrocytes was reduced in vitro. Helper T cells can release granzyme B causing sublethal injury to astrocytes, which compromises the supportive functions of astrocytes. Blocking these pathways may lead to improved resolution of neuroinflammatory lesions.
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http://dx.doi.org/10.1002/glia.23503DOI Listing
April 2019

Peripherally derived macrophages modulate microglial function to reduce inflammation after CNS injury.

PLoS Biol 2018 10 17;16(10):e2005264. Epub 2018 Oct 17.

Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada.

Infiltrating monocyte-derived macrophages (MDMs) and resident microglia dominate central nervous system (CNS) injury sites. Differential roles for these cell populations after injury are beginning to be uncovered. Here, we show evidence that MDMs and microglia directly communicate with one another and differentially modulate each other's functions. Importantly, microglia-mediated phagocytosis and inflammation are suppressed by infiltrating macrophages. In the context of spinal cord injury (SCI), preventing such communication increases microglial activation and worsens functional recovery. We suggest that macrophages entering the CNS provide a regulatory mechanism that controls acute and long-term microglia-mediated inflammation, which may drive damage in a variety of CNS conditions.
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http://dx.doi.org/10.1371/journal.pbio.2005264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6205650PMC
October 2018

Human central nervous system astrocytes support survival and activation of B cells: implications for MS pathogenesis.

J Neuroinflammation 2018 Apr 19;15(1):114. Epub 2018 Apr 19.

Neuroimmunology Unit, Montreal Neurological Institute, McGill University, 3801 University Street, Room 111, Montréal , QC, H3A 2B3, Canada.

Background: The success of clinical trials of selective B cell depletion in patients with relapsing multiple sclerosis (MS) indicates B cells are important contributors to peripheral immune responses involved in the development of new relapses. Such B cell contribution to peripheral inflammation likely involves antibody-independent mechanisms. Of growing interest is the potential that B cells, within the MS central nervous system (CNS), may also contribute to the propagation of CNS-compartmentalized inflammation in progressive (non-relapsing) disease. B cells are known to persist in the inflamed MS CNS and are more recently described as concentrated in meningeal immune-cell aggregates, adjacent to the subpial cortical injury which has been associated with progressive disease. How B cells are fostered within the MS CNS and how they may contribute locally to the propagation of CNS-compartmentalized inflammation remain to be elucidated.

Methods: We considered whether activated human astrocytes might contribute to B cell survival and function through soluble factors. B cells from healthy controls (HC) and untreated MS patients were exposed to primary human astrocytes that were either maintained under basal culture conditions (non-activated) or pre-activated with standard inflammatory signals. B cell exposure to astrocytes included direct co-culture, co-culture in transwells, or exposure to astrocyte-conditioned medium. Following the different exposures, B cell survival and expression of T cell co-stimulatory molecules were assessed by flow cytometry, as was the ability of differentially exposed B cells to induce activation of allogeneic T cells.

Results: Secreted factors from both non-activated and activated human astrocytes robustly supported human B cell survival. Soluble products of pre-activated astrocytes also induced B cell upregulation of antigen-presenting cell machinery, and these B cells, in turn, were more efficient activators of T cells. Astrocyte-soluble factors could support survival and activation of B cell subsets implicated in MS, including memory B cells from patients with both relapsing and progressive forms of disease.

Conclusions: Our findings point to a potential mechanism whereby activated astrocytes in the inflamed MS CNS not only promote a B cell fostering environment, but also actively support the ability of B cells to contribute to the propagation of CNS-compartmentalized inflammation, now thought to play key roles in progressive disease.
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http://dx.doi.org/10.1186/s12974-018-1136-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5907187PMC
April 2018

Glioblastoma stem cell-derived exosomes induce M2 macrophages and PD-L1 expression on human monocytes.

Oncoimmunology 2018;7(4):e1412909. Epub 2018 Jan 16.

Departments of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.

Exosomes can mediate a dynamic method of communication between malignancies, including those sequestered in the central nervous system and the immune system. We sought to determine whether exosomes from glioblastoma (GBM)-derived stem cells (GSCs) can induce immunosuppression. We report that GSC-derived exosomes (GDEs) have a predilection for monocytes, the precursor to macrophages. The GDEs traverse the monocyte cytoplasm, cause a reorganization of the actin cytoskeleton, and skew monocytes toward the immune suppresive M2 phenotype, including programmed death-ligand 1 (PD-L1) expression. Mass spectrometry analysis demonstrated that the GDEs contain a variety of components, including members of the signal transducer and activator of transcription 3 (STAT3) pathway that functionally mediate this immune suppressive switch. Western blot analysis revealed that upregulation of PD-L1 in GSC exosome-treated monocytes and GBM-patient-infiltrating CD14 cells predominantly correlates with increased phosphorylation of STAT3, and in some cases, with phosphorylated p70S6 kinase and Erk1/2. Cumulatively, these data indicate that GDEs are secreted GBM-released factors that are potent modulators of the GBM-associated immunosuppressive microenvironment.
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http://dx.doi.org/10.1080/2162402X.2017.1412909DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5889290PMC
January 2018

Immunology of oligodendrocyte precursor cells in vivo and in vitro.

J Neuroimmunol 2019 Jun 13;331:28-35. Epub 2018 Mar 13.

Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada. Electronic address:

Remyelination following myelin/oligodendrocyte injury in the central nervous system (CNS) is dependent on oligodendrocyte progenitor cells (OPCs) migrating into lesion sites, differentiating into myelinating oligodendrocytes (OLs), and ensheathing axons. Experimental models indicate that robust OPC-dependent remyelination can occur in the CNS; in contrast, histologic and imaging studies of lesions in the human disease multiple sclerosis (MS) indicate the variable extent of this response, which is particularly limited in more chronic MS lesions. Immune-mediated mechanisms can contribute either positively or negatively to the presence and functional responses of OPCs. This review addresses i) the molecular signature and functional properties of OPCs in the adult human brain; ii) the status (presence and function) of OPCs in MS lesions; iii) experimental models and in vitro data highlighting the contribution of adaptive and innate immune constituents to OPC injury and remyelination; and iv) effects of MS-directed immunotherapies on OPCs, either directly or indirectly via effects on specific immune constituents.
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http://dx.doi.org/10.1016/j.jneuroim.2018.03.006DOI Listing
June 2019

MerTK-mediated regulation of myelin phagocytosis by macrophages generated from patients with MS.

Neurol Neuroimmunol Neuroinflamm 2017 Nov 16;4(6):e402. Epub 2017 Oct 16.

Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia.

Objective: To document functional differences between monocyte-derived macrophages (MDMs) of patients with MS and the ability of age/sex-matched healthy donor cells to phagocytose human myelin and to investigate the molecular mechanisms that underlie this.

Methods: MDMs were derived from peripheral blood monocytes of 25 untreated patients with relapsing-remitting MS and secondary progressive MS and age/sex-matched healthy controls (HCs). Phagocytosis was assessed by flow cytometry using fluorescently labeled human myelin. Quantification of messenger RNA and protein expression of Tyro3, Axl, and MerTK family molecules was determined by quantitative PCR, Western blotting, and flow cytometry.

Results: Cells of patients with MS display a reduced ability to phagocytose human myelin but not red blood cells as compared to matched HCs. These cells express significantly lower levels of the phagocytic tyrosine kinase receptor, MerTK, and its natural ligand, growth arrest-specific 6, independently of the activation state of the cells. Increased expression of interleukin 10 following myelin uptake by healthy donor cells is lost in MDMs of patients with MS; this effect is mediated through the MerTK pathway. Treatment of MS cells with transforming growth factor β (TGFβ) restored both phagocytosis and expression deficits.

Conclusions: We describe a molecular mechanism that underlies a defect in myelin phagocytosis by macrophages generated from patients with MS. This abnormality involves decreased expression of MerTK and its ligands and can be rescued by treatment with TGFβ.
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http://dx.doi.org/10.1212/NXI.0000000000000402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5777663PMC
November 2017

Corrigendum: Divergent Neuroinflammatory Regulation of Microglial TREM Expression and Involvement of NF-κB.

Front Cell Neurosci 2017 24;11:256. Epub 2017 Aug 24.

The Royal (Dick) School of Veterinary Studies, University of EdinburghMidlothian, UK.

[This corrects the article on p. 56 in vol. 11, PMID: 28303091.].
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http://dx.doi.org/10.3389/fncel.2017.00256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5609595PMC
August 2017

Distinct age and differentiation-state dependent metabolic profiles of oligodendrocytes under optimal and stress conditions.

PLoS One 2017 8;12(8):e0182372. Epub 2017 Aug 8.

Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.

Within the microenvironment of multiple sclerosis lesions, oligodendrocytes are subject to metabolic stress reflecting effects of focal ischemia and inflammation. Previous studies have shown that under optimal conditions in vitro, the respiratory activity of human adult brain-derived oligodendrocytes is lower and more predominantly glycolytic compared to oligodendrocytes differentiated in vitro from post natal rat brain oligodendrocyte progenitor cells. In response to sub-lethal metabolic stress, adult human oligodendrocytes reduce overall energy production rate impacting the capacity to maintain myelination. Here, we directly compare the metabolic profiles of oligodendrocytes derived from adult rat brain with oligodendrocytes newly differentiated in vitro from oligodendrocyte progenitor cells obtained from the post natal rat brain, under both optimal culture and metabolic stress (low/no glucose) conditions. Oxygen consumption and extracellular acidification rates were measured using a Seahorse extracellular flux analyzer. Our findings indicate that under optimal conditions, adult rat oligodendrocytes preferentially use glycolysis whereas newly differentiated post natal rat oligodendrocytes, and the oligodendrocyte progenitor cells from which they are derived, mainly utilize oxidative phosphorylation to produce ATP. Metabolic stress increases the rate of ATP production via oxidative phosphorylation and significantly reduces glycolysis in adult oligodendrocytes. The rate of ATP production was relatively unchanged in newly differentiated post natal oligodendrocytes under these stress conditions, while it was significantly reduced in oligodendrocyte progenitor cells. Our study indicates that both age and maturation influence the metabolic profile under optimal and stressed conditions, emphasizing the need to consider these variables for in vitro studies that aim to model adult human disease.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182372PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5549710PMC
October 2017

Comparative morphology and phagocytic capacity of primary human adult microglia with time-lapse imaging.

J Neuroimmunol 2017 09 22;310:143-149. Epub 2017 May 22.

Department of Exercise Science, Concordia University, Montréal, QC H4B 1R6, Canada; Department of Biology, Concordia University, Canada; PERFORM Centre, Concordia University, Canada; Center for Structural and Functional Genomics, Concordia University, Canada. Electronic address:

Microglia provide immune surveillance within the brain and spinal cord. Various microglial morphologies include ramified, amoeboid, and pseudopodic. The link between form and function is not clear, especially for human adult microglia which are limited in availability for study. Here, we examined primary human microglia isolated from normal-appearing white matter. Pseudopodic and amoeboid microglia were effective phagocytes, taking up E. coli bioparticles using ruffled cell membrane sheets and retrograde transport. Pseudopodic and amoeboid microglia were more effective phagocytes as compared to ramified microglia or monocyte-derived dendritic cells. Thus, amoeboid and pseudopodic microglia may both be effective as brain scavengers.
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http://dx.doi.org/10.1016/j.jneuroim.2017.05.012DOI Listing
September 2017

A Highly Efficient Human Pluripotent Stem Cell Microglia Model Displays a Neuronal-Co-culture-Specific Expression Profile and Inflammatory Response.

Stem Cell Reports 2017 06;8(6):1727-1742

Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK; Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK. Electronic address:

Microglia are increasingly implicated in brain pathology, particularly neurodegenerative disease, with many genes implicated in Alzheimer's, Parkinson's, and motor neuron disease expressed in microglia. There is, therefore, a need for authentic, efficient in vitro models to study human microglial pathological mechanisms. Microglia originate from the yolk sac as MYB-independent macrophages, migrating into the developing brain to complete differentiation. Here, we recapitulate microglial ontogeny by highly efficient differentiation of embryonic MYB-independent iPSC-derived macrophages then co-culture them with iPSC-derived cortical neurons. Co-cultures retain neuronal maturity and functionality for many weeks. Co-culture microglia express key microglia-specific markers and neurodegenerative disease-relevant genes, develop highly dynamic ramifications, and are phagocytic. Upon activation they become more ameboid, releasing multiple microglia-relevant cytokines. Importantly, co-culture microglia downregulate pathogen-response pathways, upregulate homeostatic function pathways, and promote a more anti-inflammatory and pro-remodeling cytokine response than corresponding monocultures, demonstrating that co-cultures are preferable for modeling authentic microglial physiology.
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http://dx.doi.org/10.1016/j.stemcr.2017.05.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5470330PMC
June 2017

Pro-inflammatory activation of primary microglia and macrophages increases 18 kDa translocator protein expression in rodents but not humans.

J Cereb Blood Flow Metab 2017 Aug 22;37(8):2679-2690. Epub 2017 May 22.

6 Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland.

The 18kDa Translocator Protein (TSPO) is the most commonly used tissue-specific marker of inflammation in positron emission tomography (PET) studies. It is expressed in myeloid cells such as microglia and macrophages, and in rodent myeloid cells expression increases with cellular activation. We assessed the effect of myeloid cell activation on TSPO gene expression in both primary human and rodent microglia and macrophages in vitro, and also measured TSPO radioligand binding with H-PBR28 in primary human macrophages. As observed previously, we found that TSPO expression increases (∼9-fold) in rodent-derived macrophages and microglia upon pro-inflammatory stimulation. However, TSPO expression does not increase with classical pro-inflammatory activation in primary human microglia (fold change 0.85 [95% CI 0.58-1.12], p = 0.47). In contrast, pro-inflammatory activation of human monocyte-derived macrophages is associated with a reduction of both TSPO gene expression (fold change 0.60 [95% CI 0.45-0.74], p = 0.02) and TSPO binding site abundance (fold change 0.61 [95% CI 0.49-0.73], p < 0.0001). These findings have important implications for understanding the biology of TSPO in activated macrophages and microglia in humans. They are also clinically relevant for the interpretation of PET studies using TSPO targeting radioligands, as they suggest changes in TSPO expression may reflect microglial and macrophage density rather than activation phenotype.
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http://dx.doi.org/10.1177/0271678X17710182DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536262PMC
August 2017

Sublethal oligodendrocyte injury: A reversible condition in multiple sclerosis?

Ann Neurol 2017 Jun 2;81(6):811-824. Epub 2017 Jun 2.

Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.

Objective: Degeneration of oligodendroglial distal processes has been identified as an early event in multiple sclerosis (MS) lesion development. Our objective was to further define the development of the "dying-back" oligodendrocyte lesion in situ and to model the development and potential reversibility of such responses using dissociated cultures of adult human brain-derived oligodendrocytes.

Methods: In situ analyses were performed on glutaraldehyde-fixed thin sections of clinically acute and pathologically active cases of MS. In vitro studies were conducted using adult human brain-derived oligodendrocytes challenged by metabolic stress conditions (low nutrient/glucose).

Results: In situ analyses indicated a spectrum of myelin changes in the presence of morphologically intact oligodendrocytes; these included degeneration of the inner cytoplasmic tongue with increasing sizes of intramyelinic bleb formation that could result in radial fractures of the myelin sheath. Macrophages with ingested myelin fragments were identified only once the fragmentation was established. In vitro studies indicated that oligodendrocyte process retraction, which was linked to reduced glycolytic respiratory activity, is reversible until a critical time point. Subsequent cell death was not linked to caspase-3-dependent programs. Gene expression studies conducted at the latest reversible time point revealed reduced expression of pathways associated with cell process outgrowth and myelination, as well as with metabolic activity.

Interpretation: Our findings reveal the potential to protect and possibly restore myelin elaborated by existent oligodendrocytes in early and evolving MS lesions, and suggest the necessity of ongoing studies of the mechanisms underlying subsequent adult human oligodendrocyte cell death. Ann Neurol 2017;81:811-824.
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http://dx.doi.org/10.1002/ana.24944DOI Listing
June 2017

iPSC-Derived Human Microglia-like Cells to Study Neurological Diseases.

Neuron 2017 Apr;94(2):278-293.e9

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. Electronic address:

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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http://dx.doi.org/10.1016/j.neuron.2017.03.042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482419PMC
April 2017