title: Characterizing primary human microglia: A comparative study with myeloid subsets and culture models.
abstract: The biology of microglia has become subject to intense study, as they are widely recognized as crucial determinants of normal and pathologic brain functioning. While they are well studied in animal models, it is still strongly debated what specifies most accurately the phenotype and functioning of microglia in the human brain. In this study, we therefore isolated microglia from postmortem human brain tissue of corpus callosum (CC) and frontal cortex (CTX). The cells were phenotyped for a panel of typical microglia markers and genes involved in myeloid cell biology. Furthermore, their response to pro- and anti-inflammatory stimuli was assessed. The microglia were compared to key human myeloid cell subsets, including monocytes, monocyte-derived macrophages and monocyte-derived dendritic cells, and several commonly used microglial cell models. Protein and mRNA expression profiles partly differed between microglia isolated from CC and frontal cortex and were clearly distinct from other myeloid subsets. Microglia responded to both pro- (LPS or poly I:C) and anti-inflammatory (IL-4 or dexamethasone) stimuli. Interestingly, pro-inflammatory responses differed between microglia and monocyte-derived macrophages, as the former responded more strongly to poly I:C and the latter more strongly to LPS. Furthermore, we defined a large phenotypic discrepancy between primary human microglia and currently used microglial cell models and cell lines. In conclusion, we further delineated the unique and specific features that discriminate human microglia from other myeloid subsets, and we show that currently used cellular models only partly reflect the phenotype of primary human microglia. GLIA 2016;64:1857-1868.
authors.affiliation: Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (BCRM-UMCU), Utrecht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Melief
authors.affiliation: Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (BCRM-UMCU), Utrecht, The Netherlands.|Department of Translational Neuroscience, BCRM-UMCU, Utrecht, The Netherlands.
authors.forename: M A M
authors.initials: MA
authors.lastname: Sneeboer
authors.affiliation: Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (BCRM-UMCU), Utrecht, The Netherlands.|Department of Translational Neuroscience, BCRM-UMCU, Utrecht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Litjens
authors.affiliation: Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (BCRM-UMCU), Utrecht, The Netherlands.|Department of Translational Neuroscience, BCRM-UMCU, Utrecht, The Netherlands.
authors.forename: P R
authors.initials: PR
authors.lastname: Ormel
authors.affiliation: Department of Translational Neuroscience, BCRM-UMCU, Utrecht, The Netherlands.
authors.forename: S J M C
authors.initials: SJ
authors.lastname: Palmen
authors.affiliation: Netherlads Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, The Netherlands.
authors.forename: I
authors.initials: I
authors.lastname: Huitinga
authors.affiliation: Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (BCRM-UMCU), Utrecht, The Netherlands.
authors.forename: R S
authors.initials: RS
authors.lastname: Kahn
authors.affiliation: Department of Translational Neuroscience, BCRM-UMCU, Utrecht, The Netherlands.|Netherlads Institute for Neuroscience, An Institute of the Royal Academy of Arts and Sciences, Amsterdam, The Netherlands.|Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands.
authors.forename: E M
authors.initials: EM
authors.lastname: Hol
authors.affiliation: Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (BCRM-UMCU), Utrecht, The Netherlands. L.D.deWitte@umcutrecht.nl.|Department of Translational Neuroscience, BCRM-UMCU, Utrecht, The Netherlands. L.D.deWitte@umcutrecht.nl.
authors.forename: L D
authors.initials: LD
authors.lastname: de Witte
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003337:Corpus Callosum / Q000166:cytology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D005434:Flow Cytometry; D005625:Frontal Lobe / Q000166:cytology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D017628:Microglia / Q000187:drug effects / Q000502:physiology*; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D022423:Myeloid Cells / Q000145:classification* / Q000502:physiology*; D011070:Poly I-C / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D000893:Anti-Inflammatory Agents; D015703:Antigens, CD; D016207:Cytokines; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D015847:Interleukin-4; D003907:Dexamethasone; D011070:Poly I-C
keywords: characterization; models and cell lines; primary human microglia; responsiveness