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Brifault C, Kwon H, Campana WM, Gonias SL. LRP1 deficiency in microglia blocks neuro-inflammation in the spinal dorsal horn and neuropathic pain processing. Glia 2019; 67:1210-1224. [PMID: 30746765 DOI: 10.1002/glia.23599] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/18/2018] [Accepted: 01/22/2019] [Indexed: 01/29/2023]
Abstract
Following injury to the peripheral nervous system (PNS), microglia in the spinal dorsal horn (SDH) become activated and contribute to the development of local neuro-inflammation, which may regulate neuropathic pain processing. The molecular mechanisms that control microglial activation and its effects on neuropathic pain remain incompletely understood. We deleted the gene encoding the plasma membrane receptor, LDL Receptor-related Protein-1 (LRP1), conditionally in microglia using two distinct promoter-Cre recombinase systems in mice. LRP1 deletion in microglia blocked development of tactile allodynia, a neuropathic pain-related behavior, after partial sciatic nerve ligation (PNL). LRP1 deletion also substantially attenuated microglial activation and pro-inflammatory cytokine expression in the SDH following PNL. Because LRP1 shedding from microglial plasma membranes generates a highly pro-inflammatory soluble product, we demonstrated that factors which activate spinal cord microglia, including lipopolysaccharide (LPS) and colony-stimulating factor-1, promote LRP1 shedding. Proteinases known to mediate LRP1 shedding, including ADAM10 and ADAM17, were expressed at increased levels in the SDH after PNL. Furthermore, LRP1-deficient microglia in cell culture expressed significantly decreased levels of interleukin-1β and interleukin-6 when treated with LPS. We conclude that in the SDH, microglial LRP1 plays an important role in establishing and/or amplifying local neuro-inflammation and neuropathic pain following PNS injury. The responsible mechanism most likely involves proteolytic release of LRP1 from the plasma membrane to generate a soluble product that functions similarly to pro-inflammatory cytokines in mediating crosstalk between cells in the SDH and in regulating neuropathic pain.
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Affiliation(s)
- Coralie Brifault
- Department of Pathology, University of California San Diego, La Jolla, California.,Department of Anesthesiology, University of California San Diego, La Jolla, California
| | - HyoJun Kwon
- Department of Anesthesiology, University of California San Diego, La Jolla, California
| | - Wendy M Campana
- Department of Anesthesiology, University of California San Diego, La Jolla, California.,Department of Anesthesiology, Veterans Administration San Diego HealthCare System, San Diego, California
| | - Steven L Gonias
- Department of Pathology, University of California San Diego, La Jolla, California
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52
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Milanova IV, Kalsbeek MJT, Wang XL, Korpel NL, Stenvers DJ, Wolff SEC, de Goede P, Heijboer AC, Fliers E, la Fleur SE, Kalsbeek A, Yi CX. Diet-Induced Obesity Disturbs Microglial Immunometabolism in a Time-of-Day Manner. Front Endocrinol (Lausanne) 2019; 10:424. [PMID: 31316470 PMCID: PMC6611391 DOI: 10.3389/fendo.2019.00424] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/12/2019] [Indexed: 12/16/2022] Open
Abstract
Background: Disturbance of immunometabolic signaling is a key process involved in the progression of obesity. Microglia-the resident immune cells in the brain, initiate local immune responses. It is known that hypercaloric diets lead to microglial activation. Previously, we observed that hypothalamic microglial cells from mice fed high-fat diet (HFD) lose their day/night rhythm and are constantly activated. However, little is known about daily rhythmicity in microglial circadian, immune and metabolic functions, either in lean or obese conditions. Therefore, we hypothesized that HFD disturbs microglial immunometabolism in a day/night-dependent manner. Methods: Obesity was induced in Wistar rats by feeding them HFD ad libitum for the duration of 8 weeks. Microglia were isolated from HFD- and chow-fed control animals at six time points during 24 h [every 4 h starting 2 h after lights on, i.e., Zeitgeber Time 2 (ZT2)]. Gene expression was evaluated using quantitative RT-PCR. JTK_Cycle software was used to estimate daily rhythmicity. Statistical analysis was performed with two-way ANOVA test. Results: Consumption of the obesogenic diet resulted in a 40 g significantly higher body weight gain in week 8, compared to chow diet (p < 0.0001), associated with increased adiposity. We observed significant rhythmicity of circadian clock genes in microglia under chow conditions, which was partially lost in diet-induced obesity (DIO). Microglial immune gene expression also showed time-of-day differences, which were disrupted in HFD-fed animals. Microglia responded to the obesogenic conditions by a shift of substrate utilization with decreased glutamate and glucose metabolism in the active period of the animals, and an overall increase of lipid metabolism, as indicated by gene expression evaluation. Additionally, data on mitochondria bioenergetics and dynamics suggested an increased energy production in microglia during the inactive period on HFD. Finally, evaluation of monocyte functional gene expression showed small or absent effect of HFD on peripheral myeloid cells, suggesting a cell-specific microglial inflammatory response in DIO. Conclusions: An obesogenic diet affects microglial immunometabolism in a time-of-day dependent manner. Given the central role of the brain in energy metabolism, a better knowledge of daily rhythms in microglial immunometabolism could lead to a better understanding of the pathogenesis of obesity.
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Affiliation(s)
- Irina V. Milanova
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Martin J. T. Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Xiao-Lan Wang
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Nikita L. Korpel
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Dirk Jan Stenvers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Samantha E. C. Wolff
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Paul de Goede
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Annemieke C. Heijboer
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Susanne E. la Fleur
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- *Correspondence: Chun-Xia Yi
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Zhang M, Gillaspy AF, Gipson JR, Cassidy BR, Nave JL, Brewer MF, Stoner JA, Chen J, Drevets DA. Neuroinvasive Listeria monocytogenes Infection Triggers IFN-Activation of Microglia and Upregulates Microglial miR-155. Front Immunol 2018; 9:2751. [PMID: 30538705 PMCID: PMC6277692 DOI: 10.3389/fimmu.2018.02751] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/08/2018] [Indexed: 11/17/2022] Open
Abstract
MicroRNA (miR) miR-155 modulates microglial activation and polarization, but its role in activation of microglia during bacterial brain infection is unclear. We studied miR-155 expression in brains of C57BL/6 (B6.WT) mice infected i.p. with the neuro-invasive bacterial pathogen Listeria monocytogenes (L. monocytogenes). Infected mice were treated with ampicillin starting 2 days (d) post-infection (p.i.) and analyzed 3d, 7d, and 14d p.i. Virulent L. monocytogenes strains EGD and 10403s upregulated miR-155 in whole brain 7 d p.i. whereas infection with avirulent, non-neurotropic Δhly or ΔactA L. monocytogenes mutants did not. Similarly, infection with virulent but not mutated bacteria upregulated IFN-γ mRNA in the brain at 7 d p.i. Upregulation of miR-155 in microglia was confirmed by qPCR of flow cytometry-sorted CD45intCD11bpos brain cells. Subsequently, brain leukocyte influxes and gene expression in sorted microglia were compared in L. monocytogenes-infected B6.WT and B6.Cg-Mir155tm1.1Rsky/J (B6.miR-155−/−) mice. Brain influxes of Ly-6Chigh monocytes and upregulation of IFN-related genes in microglia were similar to B6.WT mice at 3 d p.i. In contrast, by d 7 p.i. expressions of microglial IFN-related genes, including markers of M1 polarization, were significantly lower in B6.miR-155−/− mice and by 14 d p.i., influxes of activated T-lymphocytes were markedly reduced. Notably, CD45highCD11bpos brain cells from B6.miR-155−/− mice isolated at 7 d p.i. expressed 2-fold fewer IFN-γ transcripts than did cells from B6.WT mice suggesting reduced IFN-γ stimulation contributed to dampened gene expression in B6.miR-155−/− microglia. Lastly, in vitro stimulation of 7 d p.i. brain cells with heat-killed L. monocytogenes induced greater production of TNF in B6.miR-155−/− microglia than in B6.WT microglia. Thus, miR-155 affects brain inflammation by multiple mechanisms during neuroinvasive L. monocytogenes infection. Peripheral miR-155 promotes brain inflammation through its required role in optimal development of IFN-γ-secreting lymphocytes that enter the brain and activate microglia. Microglial miR-155 promotes M1 polarization, and also inhibits inflammatory responses to stimulation by heat-killed L. monocytogenes, perhaps by targeting Tab2.
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Affiliation(s)
- Miao Zhang
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Allison F Gillaspy
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Laboratory for Molecular Biology and Cytometry Research, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jenny R Gipson
- Laboratory for Molecular Biology and Cytometry Research, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Benjamin R Cassidy
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jessica L Nave
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Misty F Brewer
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Julie A Stoner
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jie Chen
- Histology and Immunohistochemistry Core, Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Douglas A Drevets
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Veterans Affairs Medical Center, Oklahoma City, OK, United States
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54
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Matt SM, Zimmerman JD, Lawson MA, Bustamante AC, Uddin M, Johnson RW. Inhibition of DNA Methylation With Zebularine Alters Lipopolysaccharide-Induced Sickness Behavior and Neuroinflammation in Mice. Front Neurosci 2018; 12:636. [PMID: 30279646 PMCID: PMC6153314 DOI: 10.3389/fnins.2018.00636] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 08/24/2018] [Indexed: 12/24/2022] Open
Abstract
Activity of DNA methyltransferases (DNMTs), the enzymes that catalyze DNA methylation, is dynamically regulated in the brain. DNMT inhibitors alter DNA methylation globally in the brain and at individual neural plasticity-associated genes, but how DNMT inhibitors centrally influence lipopolysaccharide (LPS)-induced neuroinflammation is not known. We investigated whether the DMNT inhibitor, zebularine, would alter sickness behavior, DNA methylation of the Il-1β promoter and expression of inflammatory genes in hippocampus and microglia. Contrary to our hypothesis that zebularine may exaggerate LPS-induced sickness response and neuroinflammation, adult mice treated with an intracerebroventricular (ICV) injection of zebularine prior to LPS had surprisingly faster recovery of burrowing behavior compared to mice treated with LPS. Further, genes of inflammatory markers, epigenetic regulators, and the microglial sensory apparatus (i.e., the sensome) were differentially expressed by zebularine alone or in combination with LPS. Bisulfite pyrosequencing revealed that ICV zebularine led to decreased DNA methylation of two CpG sites near the Il-1β proximal promoter alone or in combination with LPS. Zebularine treated mice still exhibited decreased DNA methylation 48 h after treatment when LPS-induced sickness behavior as well as hippocampal and microglial gene expression were similar to control mice. Taken together, these data suggest that decreased DNA methylation, specifically of the Il-1β promoter region, with a DNMT inhibitor in the brain disrupts molecular mechanisms of neuroinflammation.
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Affiliation(s)
- Stephanie M Matt
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Animal Sciences Laboratory, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jalisa D Zimmerman
- Animal Sciences Laboratory, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Marcus A Lawson
- Animal Sciences Laboratory, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Angela C Bustamante
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Monica Uddin
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Rodney W Johnson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Animal Sciences Laboratory, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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55
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Matt SM, Allen JM, Lawson MA, Mailing LJ, Woods JA, Johnson RW. Butyrate and Dietary Soluble Fiber Improve Neuroinflammation Associated With Aging in Mice. Front Immunol 2018; 9:1832. [PMID: 30154787 PMCID: PMC6102557 DOI: 10.3389/fimmu.2018.01832] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/25/2018] [Indexed: 12/13/2022] Open
Abstract
Aging results in chronic systemic inflammation that can alter neuroinflammation of the brain. Specifically, microglia shift to a pro-inflammatory phenotype predisposing them to hyperactivation upon stimulation by peripheral immune signals. It is proposed that certain nutrients can delay brain aging by preventing or reversing microglial hyperactivation. Butyrate, a short-chain fatty acid (SCFA) produced primarily by bacterial fermentation of fiber in the colon, has been extensively studied pharmacologically as a histone deacetylase inhibitor and serves as an attractive therapeutic candidate, as butyrate has also been shown to be anti-inflammatory and improve memory in animal models. In this study, we demonstrate that butyrate can attenuate pro-inflammatory cytokine expression in microglia in aged mice. It is still not fully understood, however, if an increase in butyrate-producing bacteria in the gut as a consequence of a diet high in soluble fiber could affect microglial activation during aging. Adult and aged mice were fed either a 1% cellulose (low fiber) or 5% inulin (high fiber) diet for 4 weeks. Findings indicate that mice fed inulin had an altered gut microbiome and increased butyrate, acetate, and total SCFA production. In addition, histological scoring of the distal colon demonstrated that aged animals on the low fiber diet had increased inflammatory infiltrate that was significantly reduced in animals consuming the high fiber diet. Furthermore, gene expression of inflammatory markers, epigenetic regulators, and the microglial sensory apparatus (i.e., the sensome) were altered by both diet and age, with aged animals exhibiting a more anti-inflammatory microglial profile on the high fiber diet. Taken together, high fiber supplementation in aging is a non-invasive strategy to increase butyrate levels, and these data suggest that an increase in butyrate through added soluble fiber such as inulin could counterbalance the age-related microbiota dysbiosis, potentially leading to neurological benefits.
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Affiliation(s)
- Stephanie M. Matt
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jacob M. Allen
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Marcus A. Lawson
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Lucy J. Mailing
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jeffrey A. Woods
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Rodney W. Johnson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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56
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Timmerman R, Burm SM, Bajramovic JJ. An Overview of in vitro Methods to Study Microglia. Front Cell Neurosci 2018; 12:242. [PMID: 30127723 PMCID: PMC6087748 DOI: 10.3389/fncel.2018.00242] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/18/2018] [Indexed: 12/11/2022] Open
Abstract
Neuroinflammation is a common feature in neurodegenerative diseases and strategies to modulate neuroinflammatory processes are increasingly considered as therapeutic options. In such strategies, glia cells rather than neurons represent the cellular targets. Microglia, the resident macrophages of the central nervous system, are principal players in neuroinflammation and detailed cellular biological knowledge of this particular cell type is therefore of pivotal importance. The last decade has shed new light on the origin, characteristics and functions of microglia, underlining the need for specific in vitro methodology to study these cells in detail. In this review we provide a comprehensive overview of existing methodology such as cell lines, stem cell-derived microglia and primary dissociated cell cultures, as well as discuss recent developments. As there is no in vitro method available yet that recapitulates all hallmarks of adult homeostatic microglia, we also discuss the advantages and limitations of existing models across different species.
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Affiliation(s)
- Raissa Timmerman
- Alternatives Unit, Biomedical Primate Research Centre, Rijswijk, Netherlands
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57
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Song S, Wang S, Pigott VM, Jiang T, Foley LM, Mishra A, Nayak R, Zhu W, Begum G, Shi Y, Carney KE, Hitchens TK, Shull GE, Sun D. Selective role of Na + /H + exchanger in Cx3cr1 + microglial activation, white matter demyelination, and post-stroke function recovery. Glia 2018; 66:2279-2298. [PMID: 30043461 DOI: 10.1002/glia.23456] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/27/2018] [Accepted: 04/24/2018] [Indexed: 12/22/2022]
Abstract
Na+ /H+ exchanger (NHE1) activation is required for multiple microglial functions. We investigated effects of selective deletion of microglial Nhe1 in Cx3cr1-CreER ;Nhe1f/f mice on neuroinflammation and tissue repair after ischemic stroke. Infarct volume was similar in corn oil or tamoxifen (Tam)-treated mice at 48 hr and 14 days post-stroke. However, the Tam-treated mice showed significantly higher survival rate and faster neurological function recovery during day 1-14 post-stroke. Deletion of microglial Nhe1 prevented the elevation of CD11b+ /CD45low-med microglia in the ischemic hemisphere at day 3 post-stroke, but stimulated expression of Ym1, CD68, TGF-β, IL-10, decreased expression of CD86 and IL-1β, and reduced GFAP+ reactive astrocytes. Moreover, at day 14 post-stroke, enhanced white matter myelination was detected in the microglial Nhe1 deleted mice. In comparison, neuronal Nhe1-null mice (the CamKII-Cre+/- ;Nhe1f/f mice) showed a significant reduction in both acute and subacute infarct volume, along with increased survival rate and moderate neurological function recovery. However, these neuronal Nhe1-null mice did not exhibit reduced activation of CD11b+ /CD45low-med microglia or CD11b+ /CD45hi macrophages in the ischemic brains, and they exhibited no reductions in white matter lesions. Taken together, this study demonstrated that deletion of microglial and neuronal Nhe1 had differential effects on ischemic brain damage. Microglial NHE1 is involved in pro-inflammatory responses during post-stroke brain tissue repair. In contrast, neuronal NHE1 activation is directly associated with the acute ischemic neuronal injury but not inflammation. Our study reveals that NHE1 protein is a potential therapeutic target critical for differential regulation of ischemic neuronal injury, demyelination and tissue repair.
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Affiliation(s)
- Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Shaoxia Wang
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Victoria M Pigott
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Tong Jiang
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Lesley M Foley
- Animal Imaging Center, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Abhishek Mishra
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Rachana Nayak
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Wen Zhu
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Yejie Shi
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Karen E Carney
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - T Kevin Hitchens
- Animal Imaging Center, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio, 45267
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania
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58
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Fang Y, Wang J, Yao L, Li C, Wang J, Liu Y, Tao X, Sun H, Liao H. The adhesion and migration of microglia to β-amyloid (Aβ) is decreased with aging and inhibited by Nogo/NgR pathway. J Neuroinflammation 2018; 15:210. [PMID: 30029608 PMCID: PMC6054753 DOI: 10.1186/s12974-018-1250-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/05/2018] [Indexed: 11/10/2022] Open
Abstract
Background Alzheimer’s disease is characterized by progressive accumulation of β-amyloid (Aβ)-containing amyloid plaques, and microglia play a critical role in internalization and degradation of Aβ. Our previous research confirmed that Nogo-66 binding to Nogo receptors (NgR) expressed on microglia inhibits cell adhesion and migration in vitro. Methods The adhesion and migration of microglia isolated from WT and APP/PS1 mice from different ages were measured by adhesion assays and transwells. After NEP1-40 (a competitive antagonist of Nogo/NgR pathway) was intracerebroventricularly administered via mini-osmotic pumps for 2 months in APP/PS1 transgenic mice, microglial recruitment toward Aβ deposits and CD36 expression were determined. Results In this paper, we found that aging led to a reduction of microglia adhesion and migration to fAβ1–42 in WT and APP/PS1 mice. The adhesion and migration of microglia to fAβ1–42 were downregulated by the Nogo, which was mediated by NgR, and the increased inhibitory effects of the Nogo could be observed in aged mice. Moreover, Rho GTPases contributed to the effects of the Nogo on adhesion and migration of microglia to fAβ1–42 by regulating cytoskeleton arrangement. Furthermore, blocking the Nogo/NgR pathway enhanced recruitment of microglia toward Aβ deposits and expression of CD36 in APP/PS1 mice. Conclusion Taken together, Nogo/NgR pathway could take part in Aβ pathology in AD by modulating microglial adhesion and migration to Aβ and the Nogo/NgR pathway might be an important target for treating AD. Electronic supplementary material The online version of this article (10.1186/s12974-018-1250-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yinquan Fang
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China.,Department of Pharmacology, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jianing Wang
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Lemeng Yao
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Chenhui Li
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Jing Wang
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Yuan Liu
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Xia Tao
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Hao Sun
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China
| | - Hong Liao
- Jiangsu Key laboratory of Drug Screening, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing, 210009, China.
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59
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Development of a characterised tool kit for the interrogation of NLRP3 inflammasome-dependent responses. Sci Rep 2018; 8:5667. [PMID: 29618797 PMCID: PMC5884858 DOI: 10.1038/s41598-018-24029-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/21/2018] [Indexed: 12/31/2022] Open
Abstract
Inflammation is an established contributor to disease and the NLRP3 inflammasome is emerging as a potential therapeutic target. A number of small molecule inhibitors of the NLRP3 pathway have been described. Here we analysed the most promising of these inhibitor classes side by side to assess relative potency and selectivity for their respective putative targets. Assessed using ASC inflammasome-speck formation, and release of IL-1β, in both human monocyte/macrophage THP1 cells and in primary mouse microglia, we compared the relative potency and selectivity of P2X7 inhibitors, inflammasome inhibitors (diarylsulfonylurea vs. the NBC series), and caspase-1 inhibitors. In doing so we are now able to provide a well characterised small molecule tool kit for interrogating and validating inflammasome-dependent responses with a range of nanomolar potency inhibitors against established points in the inflammasome pathway.
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Dostal CR, Gamsby NS, Lawson MA, McCusker RH. Glia- and tissue-specific changes in the Kynurenine Pathway after treatment of mice with lipopolysaccharide and dexamethasone. Brain Behav Immun 2018; 69:321-335. [PMID: 29241670 PMCID: PMC5857427 DOI: 10.1016/j.bbi.2017.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 12/09/2017] [Accepted: 12/09/2017] [Indexed: 12/31/2022] Open
Abstract
Behavioral symptoms associated with mood disorders have been intimately linked with immunological and psychological stress. Induction of immune and stress pathways is accompanied by increased tryptophan entry into the Kynurenine (Kyn) Pathway as governed by the rate-limiting enzymes indoleamine/tryptophan 2,3-dioxygenases (DO's: Ido1, Ido2, Tdo2). Indeed, elevated DO expression is associated with inflammation- and stress-related depression symptoms. Here we examined central (brain, astrocyte and microglia) and peripheral (lung, liver and spleen) DO expression in mice treated intraperitoneally with lipopolysaccharide (LPS) and dexamethasone (DEX) to model the response of the Kyn Pathway to inflammation and glucocorticoids. LPS-induced expression of cytokines in peripheral tissues was attenuated by DEX, confirming inflammatory and anti-inflammatory responses, respectively. Increased Kyn levels following LPS and DEX administration verified Kyn Pathway activation. Expression of multiple mRNA isoforms for each DO, which we have shown to be differentially utilized and regulated, were quantified including reference/full-length (FL) and variant (v) transcripts. LPS increased Ido1-FL in brain (∼1000-fold), a response paralleled by increased expression in both astrocytes and microglia. Central Ido1-FL was not changed by DEX; however, LPS-induced Ido1-FL was decreased by DEX in peripheral tissues. In contrast, DEX increased Ido1-v1 expression by astrocytes and microglia, but not peripheral tissues. In comparison, brain Ido2 was minimally induced by LPS or DEX. Uniquely, Ido2-v6 was LPS- and DEX-inducible in astrocytes, suggesting a unique role for astrocytes in response to inflammation and glucocorticoids. Only DEX increased central Tdo2 expression; however, peripheral Tdo2 was upregulated by either LPS or DEX. In summary, specific DO isoforms are increased by LPS and DEX, but LPS-dependent Ido1 and Ido2 induction are attenuated by DEX only in the periphery indicating that elevated DO expression and Kyn production within the brain can occur independent of the periphery. These findings demonstrate a plausible interaction between immune activation and glucocorticoids associated with depression.
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Affiliation(s)
- Carlos R. Dostal
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Medical Scholars Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Nicolaus S. Gamsby
- School of Earth, Society and Environment, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Marcus A. Lawson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Robert H. McCusker
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States,Department of Pathology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
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Stark JC, Wallace E, Lim R, Leaw B. Characterization and Isolation of Mouse Primary Microglia by Density Gradient Centrifugation. J Vis Exp 2018. [PMID: 29553508 DOI: 10.3791/57065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Microglia, the resident immune cells in the brain, are the first responders to inflammation or injury in the central nervous system. Recent research has revealed microglia to be dynamic, capable of assuming both pro-inflammatory and anti-inflammatory phenotypes. Both M1 (pro-inflammatory) and M2 (pro-reparative) phenotypes play an important role in neuroinflammatory conditions such as perinatal brain injury, and exhibit differing functions in response to certain environmental stimuli. The modulation of microglial activation has been noted to confer neuroprotection thus suggesting microglia may have therapeutic potential in brain injury. However, more research is required to better understand the role of microglia in disease, and this protocol facilitates that. The protocol described below combines a density gradient centrifugation process to reduce cellular debris, with magnetic separation, producing a highly pure sample of primary microglial cells that can be used for in vitro experimentation, without the need for 2-3 weeks culturing. Additionally, the characterization steps yield robust functional data about microglia, aiding studies to better our understanding of the polarization and priming of these cells, which has strong implications in the field of regenerative medicine.
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Affiliation(s)
| | - Euan Wallace
- The Ritchie Centre, Hudson Institute of Medical Research; Department of Obstetrics & Gynaecology, Monash University
| | - Rebecca Lim
- The Ritchie Centre, Hudson Institute of Medical Research
| | - Bryan Leaw
- The Ritchie Centre, Hudson Institute of Medical Research;
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Shiono H, Matsui T, Okada T, Ito Y. Single-step enrichment of basophils from human peripheral blood by a novel method using a Percoll density gradient. J Sep Sci 2018; 39:3062-71. [PMID: 27293108 DOI: 10.1002/jssc.201600329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 11/11/2022]
Abstract
We have developed a novel continuous flow-through cell separation method using a Percoll density gradient. This method can continuously separate a large number of cells into five fractions according to their densities. To apply this method to the separation of basophils, Percoll density gradients were modified to improve basophil enrichment. When a set of Percoll density gradients was prepared (1.071, 1.075, 1.080, 1.084, and 1.090 g/mL) the basophils in a healthy volunteer were enriched by an average of 23.1 and 63.5% at Percoll densities of 1.075 (fraction 3) and 1.080 g/mL (fraction 4), respectively. On average, the yield of basophils was 1.66 × 10(5) cells in fraction 3 and 1.61 × 10(5) cells in fraction 4 from 9 mL of peripheral blood. The expression of CD203c (cluster of differentiation 203c) on separated basophils was upregulated by anti-immunoglobulin E stimulation similar to basophils in whole blood. Histamine release induced by calcium ionophore was also observed in the separated basophils. The present method will be useful for basophil enrichment since it preserves their function without using counterflow elutriation and immunological reagents, and this method will be effective as a preparative separation for cell purification by flow cytometry.
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Affiliation(s)
- Hiroyuki Shiono
- Department of Physiology, Aichi Medical University School of Medicine, Yazako, Nagakute-city, Aichi, Japan
| | - Takuya Matsui
- Department of Physiology, Aichi Medical University School of Medicine, Yazako, Nagakute-city, Aichi, Japan
| | - Tadashi Okada
- Department of Physiology, Aichi Medical University School of Medicine, Yazako, Nagakute-city, Aichi, Japan
| | - Yoichiro Ito
- Bioseparation Technology Laboratory, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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63
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Korin B, Dubovik T, Rolls A. Mass cytometry analysis of immune cells in the brain. Nat Protoc 2018; 13:377-391. [DOI: 10.1038/nprot.2017.155] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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64
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Abstract
In this chapter, we describe a method for analyzing the vasculature of the mouse brain using single-cell transcriptomics. More specifically, we focus on the use of fluorescence-activated cell sorting (FACS) for selection of the cells of interest and sorting of these cells in a 384-well format, allowing for enrichment for the cells being studied. Furthermore, we outline the Smart-Seq2 single-cell library construction method for transforming single-cell mRNA into Illumina sequencing compatible libraries. As single-cell sequencing is still a costly technology, we take special care to describe strategies to include many quality control steps. Finally, we touch upon techniques to convert the sequencing data into a meaningful biological readout. The methods reported in this chapter can be expanded toward other tissues and will prove useful also for the study of different cell types beyond adult brain vasculature.
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Affiliation(s)
- Michael Vanlandewijck
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre (KI/AZ ICMC), Huddinge, Sweden. .,Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
| | - Christer Betsholtz
- Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre (KI/AZ ICMC), Huddinge, Sweden.,Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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65
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Wyatt-Johnson SK, Herr SA, Brewster AL. Status Epilepticus Triggers Time-Dependent Alterations in Microglia Abundance and Morphological Phenotypes in the Hippocampus. Front Neurol 2017; 8:700. [PMID: 29326654 PMCID: PMC5741821 DOI: 10.3389/fneur.2017.00700] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/06/2017] [Indexed: 12/30/2022] Open
Abstract
Status epilepticus (SE) is defined by the occurrence of prolonged “non-stop” seizures that last for at least 5 min. SE provokes inflammatory responses including the activation of microglial cells, the brain’s resident immune cells, which are thought to contribute to the neuropathology and pathophysiology of epilepsy. Microglia are professional phagocytes that resemble peripheral macrophages. Upon sensing immune disturbances, including SE, microglia become reactive, produce inflammatory cytokines, and alter their actin cytoskeleton to transform from ramified to amoeboid shapes. It is widely known that SE triggers time-dependent microglial expression of pro-inflammatory cytokines that include TNFα and IL-1β. However, less is known in regards to the spatiotemporal progression of the morphological changes, which may help define the extent of microglia reactivity after SE and potential function (surveillance, inflammatory, phagocytic). Therefore, in this study, we used the microglia/macrophage IBA1 marker to identify and count these cells in hippocampi from control rats and at 4 h, 3 days, and 2 weeks after a single episode of pilocarpine-induced SE. We identified, categorized, and counted the IBA1-positive cells with the different morphologies observed after SE in the hippocampal areas CA1, CA3, and dentate gyrus. These included ramified, hypertrophic, bushy, amoeboid, and rod. We found that the ramified phenotype was the most abundant in control hippocampi. In contrast, SE provoked time-dependent changes in the microglial morphology that was characterized by significant increases in the abundance of bushy-shaped cells at 4 h and amoeboid-shaped cells at 3 days and 2 weeks. Interestingly, a significant increase in the number of rod-shaped cells was only evident in the CA1 region at 2 weeks after SE. Taken together, these data suggest that SE triggers time-dependent alterations in the morphology of microglial cells. This detailed description of the spatiotemporal profile of SE-induced microglial morphological changes may help provide insight into their contribution to epileptogenesis.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Psychological Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, United States
| | - Seth A Herr
- Department of Psychological Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, United States
| | - Amy L Brewster
- Department of Psychological Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, West Lafayette, IN, United States
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66
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Abedi Z, Khaza'ai H, Vidyadaran S, Mutalib MSA. The Modulation of NMDA and AMPA/Kainate Receptors by Tocotrienol-Rich Fraction and Α-Tocopherol in Glutamate-Induced Injury of Primary Astrocytes. Biomedicines 2017; 5:biomedicines5040068. [PMID: 29194360 PMCID: PMC5744092 DOI: 10.3390/biomedicines5040068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/15/2017] [Accepted: 11/28/2017] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are known as structural and supporting cells in the central nervous system (CNS). Glutamate, as a main excitatory amino acid neurotransmitter in the mammalian central nervous system, can be excitotoxic, playing a key role in many chronic neurodegenerative diseases. The aim of the current study was to elucidate the potential of vitamin E in protecting glutamate-injured primary astrocytes. Hence, primary astrocytes were isolated from mixed glial cells of C57BL/6 mice by applying the EasySep® Mouse CD11b Positive Selection Kit, cultured in Dulbecco's modified Eagle medium (DMEM) and supplemented with special nutrients. The IC20 and IC50 values of glutamate, as well as the cell viability of primary astrocytes, were assessed with 100 ng/mL, 200 ng/mL, and 300 ng/mL of tocotrienol-rich fraction (TRF) and alpha-tocopherol (α-TCP), as determined by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The mitochondrial membrane potential (MMP) detected in primary astrocytes was assessed with the same concentrations of TRF and α-TCP. The expression levels of the ionotropic glutamate receptor genes (Gria2, Grin2A, GRIK1) were independently determined using RT-PCR. The purification rate of astrocytes was measured by a flow-cytometer as circa 79.4%. The IC20 and IC50 values of glutamate were determined as 10 mM and 100 mM, respectively. Exposure to 100 mM of glutamate in primary astrocytes caused the inhibition of cell viability of approximately 64.75% and 61.10% in pre- and post-study, respectively (p < 0.05). Both TRF and α-TCP (at the lowest and highest concentrations, respectively) were able to increase the MMP to 88.46% and 93.31% pre-treatment, and 78.43% and 81.22% post-treatment, respectively. Additionally, the findings showed a similar pattern for the expression level of the ionotropic glutamate receptor genes. Increased extracellular calcium concentrations were also observed, indicating that the presence of vitamin E altered the polarization of astrocytes. In conclusion, α-TCP showed better recovery and prophylactic effects as compared to TRF in the pre-treatment of glutamate-injured primary astrocytes.
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Affiliation(s)
- Zahra Abedi
- Department of Biomedical Science, Faculty of Medicine and Health Science, University Putra Malaysia, Jalan Upm, 43400 Serdang, Malaysia.
| | - Huzwah Khaza'ai
- Department of Biomedical Science, Faculty of Medicine and Health Science, University Putra Malaysia, Jalan Upm, 43400 Serdang, Malaysia.
| | - Sharmili Vidyadaran
- Department of Pathology, Faculty of Medicine and Health Science, University Putra Malaysia, Jalan Upm, 43400 Serdang, Malaysia.
| | - Mohd Sokhini Abd Mutalib
- Department of Nutrition and Dietetics, Faculty of Medicine and Health Science, University Putra Malaysia, Jalan Upm, 43400 Serdang, Malaysia.
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67
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De Luca SN, Ziko I, Dhuna K, Sominsky L, Tolcos M, Stokes L, Spencer SJ. Neonatal overfeeding by small-litter rearing sensitises hippocampal microglial responses to immune challenge: Reversal with neonatal repeated injections of saline or minocycline. J Neuroendocrinol 2017; 29. [PMID: 28983991 DOI: 10.1111/jne.12540] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/22/2017] [Accepted: 10/01/2017] [Indexed: 01/08/2023]
Abstract
The early-life period is extremely vulnerable to programming effects from the environment, many of which persist into adulthood. We have previously demonstrated that adult rats overfed as neonates have hypothalamic microglia that are hyper-responsive to an immune challenge, as well as hippocampal microglia that respond less efficiently to learning. We therefore hypothesised that neonatal overfeeding would alter the ability of hippocampal microglia to respond to an immune challenge with lipopolysaccharide (LPS) and that concomitant minocycline, a tetracycline antibiotic that suppresses microglial activity, could restore these responses. We induced neonatal overfeeding by manipulating the litter sizes in which Wistar rat pups were raised, so the pups were suckled in litters of four (neonatally overfed) or 12 (control-fed). We then examined the hippocampal microglial profiles 24 hour after an immune challenge with LPS and found that the neonatally overfed rats had dramatically increased microglial numbers in the hippocampus after immune challenge compared to control-fed rats. Attempts to reverse these effects with minocycline revealed repeated that neonatal injections, whether with minocycline or with saline, markedly suppressed microglial number and density throughout the hippocampus and abolished the difference between the groups in their responses to LPS. These data suggest that neonatal overfeeding not only can have lasting effects on hippocampal immune responses, but also that neonatal exposure to a protocol of repeated injections, irrespective of treatment, has a pronounced long-term impact, highlighting the importance of considering these effects when interpreting experimental data.
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Affiliation(s)
- S N De Luca
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - I Ziko
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - K Dhuna
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - L Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - M Tolcos
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - L Stokes
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, UK
| | - S J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
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68
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McCarthy GM, Farris SP, Blednov YA, Harris RA, Mayfield RD. Microglial-specific transcriptome changes following chronic alcohol consumption. Neuropharmacology 2017; 128:416-424. [PMID: 29101021 DOI: 10.1016/j.neuropharm.2017.10.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/05/2017] [Accepted: 10/26/2017] [Indexed: 12/21/2022]
Abstract
Microglia are fundamentally important immune cells within the central nervous system (CNS) that respond to environmental challenges to maintain normal physiological processes. Alterations in steady-state cellular function and over-activation of microglia can facilitate the initiation and progression of neuropathological conditions such as Alzheimer's disease, Multiple Sclerosis, and Major Depressive Disorder. Alcohol consumption disrupts signaling pathways including both innate and adaptive immune responses that are necessary for CNS homeostasis. Coordinate expression of these genes is not ascertained from an admixture of CNS cell-types, underscoring the importance of examining isolated cellular populations to reveal systematic gene expression changes arising from mature microglia. Unbiased RNA-Seq profiling was used to identify gene expression changes in isolated prefrontal cortical microglia in response to recurring bouts of voluntary alcohol drinking behavior. The voluntary ethanol paradigm utilizes long-term consumption ethanol that results in escalated alcohol intake and altered cortical plasticity that is seen in humans. Gene coexpression analysis identified a coordinately regulated group of genes, unique to microglia, that collectively are associated with alcohol consumption. Genes within this group are involved in toll-like receptor signaling and transforming growth factor beta signaling. Network connectivity of this group identified Siglech as a putative hub gene and highlighted the potential importance of proteases in the microglial response to chronic ethanol. In conclusion, we identified a distinctive microglial gene expression signature for neuroimmune responses related to alcohol consumption that provides valuable insight into microglia-specific changes underlying the development of substance abuse, and possibly other CNS disorders.
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Affiliation(s)
- Gizelle M McCarthy
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX 78712, United States; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, United States
| | - Sean P Farris
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX 78712, United States
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX 78712, United States
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX 78712, United States; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, United States; Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, United States
| | - R Dayne Mayfield
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX 78712, United States.
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69
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Makinde HM, Cuda CM, Just TB, Perlman HR, Schwulst SJ. Nonclassical Monocytes Mediate Secondary Injury, Neurocognitive Outcome, and Neutrophil Infiltration after Traumatic Brain Injury. THE JOURNAL OF IMMUNOLOGY 2017; 199:3583-3591. [PMID: 28993515 DOI: 10.4049/jimmunol.1700896] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/11/2017] [Indexed: 12/25/2022]
Abstract
Traumatic brain injury (TBI) results in rapid recruitment of leukocytes into the injured brain. Monocytes constitute a significant proportion of the initial infiltrate and have the potential to propagate secondary brain injury or generate an environment of repair and regeneration. Monocytes are a diverse population of cells (classical, intermediate, and nonclassical) with distinct functions, however, the recruitment order of these subpopulations to the injured brain largely remains unknown. Thus, we examined which monocyte subpopulations are required for the generation of early inflammatory infiltrate within the injured brain, and whether their depletion attenuates secondary injury or neurocognitive outcome. Global monocyte depletion correlated with significant improvements in brain edema, motor coordination, and working memory, and abrogated neutrophil infiltration into the injured brain. However, targeted depletion of classical monocytes alone had no effect on neutrophil recruitment to the site of injury, implicating the nonclassical monocyte in this process. In contrast, mice that have markedly reduced numbers of nonclassical monocytes (CX3CR1-/-) exhibited a significant reduction in neutrophil infiltration into the brain after TBI as compared with control mice. Our data suggest a critical role for nonclassical monocytes in the pathology of TBI in mice, including important clinical outcomes associated with mortality in this injury process.
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Affiliation(s)
- Hadijat M Makinde
- Division of Trauma and Critical Care, Department of Surgery, Northwestern University, Chicago, IL 60611; and
| | - Carla M Cuda
- Division of Rheumatology, Department of Medicine, Northwestern University, Chicago, IL 60611
| | - Talia B Just
- Division of Trauma and Critical Care, Department of Surgery, Northwestern University, Chicago, IL 60611; and
| | - Harris R Perlman
- Division of Rheumatology, Department of Medicine, Northwestern University, Chicago, IL 60611
| | - Steven J Schwulst
- Division of Trauma and Critical Care, Department of Surgery, Northwestern University, Chicago, IL 60611; and
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70
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Hwang HW, Saito Y, Park CY, Blachère NE, Tajima Y, Fak JJ, Zucker-Scharff I, Darnell RB. cTag-PAPERCLIP Reveals Alternative Polyadenylation Promotes Cell-Type Specific Protein Diversity and Shifts Araf Isoforms with Microglia Activation. Neuron 2017; 95:1334-1349.e5. [PMID: 28910620 DOI: 10.1016/j.neuron.2017.08.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 07/07/2017] [Accepted: 08/11/2017] [Indexed: 12/23/2022]
Abstract
Alternative polyadenylation (APA) is increasingly recognized to regulate gene expression across different cell types, but obtaining APA maps from individual cell types typically requires prior purification, a stressful procedure that can itself alter cellular states. Here, we describe a new platform, cTag-PAPERCLIP, that generates APA profiles from single cell populations in intact tissues; cTag-PAPERCLIP requires no tissue dissociation and preserves transcripts in native states. Applying cTag-PAPERCLIP to profile four major cell types in the mouse brain revealed common APA preferences between excitatory and inhibitory neurons distinct from astrocytes and microglia, regulated in part by neuron-specific RNA-binding proteins NOVA2 and PTBP2. We further identified a role of APA in switching Araf protein isoforms during microglia activation, impacting production of downstream inflammatory cytokines. Our results demonstrate the broad applicability of cTag-PAPERCLIP and a previously undiscovered role of APA in contributing to protein diversity between different cell types and cellular states within the brain.
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Affiliation(s)
- Hun-Way Hwang
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA; Department of Pathology, University of Pittsburgh, School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15213, USA.
| | - Yuhki Saito
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Christopher Y Park
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA; New York Genome Center, 101 Avenue of the Americas, New York, NY 10013, USA
| | - Nathalie E Blachère
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Yoko Tajima
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - John J Fak
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Ilana Zucker-Scharff
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Robert B Darnell
- Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA; New York Genome Center, 101 Avenue of the Americas, New York, NY 10013, USA.
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71
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Jiang X, Yu M, Ou Y, Cao Y, Yao Y, Cai P, Zhang F. Downregulation of USP4 Promotes Activation of Microglia and Subsequent Neuronal Inflammation in Rat Spinal Cord After Injury. Neurochem Res 2017; 42:3245-3253. [PMID: 28755289 DOI: 10.1007/s11064-017-2361-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 06/11/2017] [Accepted: 07/18/2017] [Indexed: 01/03/2023]
Abstract
NF-κB is involved in the activation of microglia, which induces secondary spinal cord injury (SCI). This process involves the activation of NF-κB signaling pathway by TRAF6 through its polyubiquitination function. We know that deubiquitination of TRAF6 mediated by deubiquitinating enzyme (DUB) significantly inhibits activation of NF-κB pathway. The ubiquitin-specific protease 4 (USP4) belongs to the deubiquitinase family. Therefore, we hypothesize that USP4 is involved in the microglial activation and subsequent neuronal inflammation after SCI. In this study, we examined the expression and the role of USP4 after SCI. Western blot analysis showed that the expression of USP4 was downregulated and the expression of p-p65 was upregulated in the spinal cord after SCI. Immunohistochemical and immunofluorescence staining showed that USP4 was expressed in microglia but its expression decreased after SCI. In vitro LPS-induced activation of microglia showed decreased expression of USP4 and increased expression of p-p65 and TRAF6. USP4 silencing in LPS-induced activation of microglia promoted the expression of p-p65 and TRAF6 and the secretion of TNF-α and IL-1β. In conclusion, our study provides the first evidence that in microglial cells expression of USP4 decreases after SCI in rats. The downregulation of USP4 expression may promote microglial activation and subsequent neuronal inflammation through NF-κB by attenuating the deubiquitination of TRAF6. This mechanism is of great significance in the pathophysiology of secondary SCI.
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Affiliation(s)
- Xingjie Jiang
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China.,Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong, 226001, Jiangsu, China
| | - Mingchen Yu
- Medical College, Nantong University, Nantong, 226001, Jiangsu, China
| | - Yiqing Ou
- Medical College, Nantong University, Nantong, 226001, Jiangsu, China
| | - Yong Cao
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China.,Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong, 226001, Jiangsu, China
| | - Yu Yao
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China.,Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong, 226001, Jiangsu, China
| | - Ping Cai
- Department of Orthopedics and Traumatology, Jiangsu Province Hospital of TCM, Nanjing, 210029, Jiangsu, China
| | - Feng Zhang
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China. .,Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong, 226001, Jiangsu, China.
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72
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Das A, Arifuzzaman S, Yoon T, Kim SH, Chai JC, Lee YS, Jung KH, Chai YG. RNA sequencing reveals resistance of TLR4 ligand-activated microglial cells to inflammation mediated by the selective jumonji H3K27 demethylase inhibitor. Sci Rep 2017; 7:6554. [PMID: 28747667 PMCID: PMC5529413 DOI: 10.1038/s41598-017-06914-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/21/2017] [Indexed: 02/07/2023] Open
Abstract
Persistent microglial activation is associated with the production and secretion of various pro-inflammatory genes, cytokines and chemokines, which may initiate or amplify neurodegenerative diseases. A novel synthetic histone 3 lysine 27 (H3K27) demethylase JMJD3 inhibitor, GSK-J4, was proven to exert immunosuppressive activities in macrophages. However, a genome-wide search for GSK-J4 molecular targets has not been undertaken in microglia. To study the immuno-modulatory effects of GSK-J4 at the transcriptomic level, triplicate RNA sequencing and quantitative real-time PCR analyses were performed with resting, GSK-J4-, LPS- and LPS + GSK-J4-challenged primary microglial (PM) and BV-2 microglial cells. Among the annotated genes, the transcriptional sequencing of microglia that were treated with GSK-J4 revealed a selective effect on LPS-induced gene expression, in which the induction of cytokines/chemokines, interferon-stimulated genes, and prominent transcription factors TFs, as well as previously unidentified genes that are important in inflammation was suppressed. Furthermore, we showed that GSK-J4 controls are important inflammatory gene targets by modulating STAT1, IRF7, and H3K27me3 levels at their promoter sites. These unprecedented results demonstrate that the histone demethylase inhibitor GSK-J4 could have therapeutic applications for neuroinflammatory diseases.
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Affiliation(s)
- Amitabh Das
- Institute of Natural Science & Technology, Hanyang University, Ansan, 15588, Republic of Korea
| | - Sarder Arifuzzaman
- Department of Bionanotechnology, Hanyang University, Seoul, 04673, Republic of Korea
| | - Taeho Yoon
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 15588, Republic of Korea
| | - Sun Hwa Kim
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 15588, Republic of Korea
| | - Jin Choul Chai
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 15588, Republic of Korea
| | - Young Seek Lee
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 15588, Republic of Korea
| | - Kyoung Hwa Jung
- Institute of Natural Science & Technology, Hanyang University, Ansan, 15588, Republic of Korea.
| | - Young Gyu Chai
- Department of Bionanotechnology, Hanyang University, Seoul, 04673, Republic of Korea. .,Department of Molecular & Life Sciences, Hanyang University, Ansan, 15588, Republic of Korea.
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73
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McCarthy GM, Bridges CR, Blednov YA, Harris RA. CNS cell-type localization and LPS response of TLR signaling pathways. F1000Res 2017; 6:1144. [PMID: 29043065 PMCID: PMC5621151 DOI: 10.12688/f1000research.12036.1] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/17/2017] [Indexed: 12/15/2022] Open
Abstract
Background: Innate immune signaling in the brain has emerged as a contributor to many central nervous system (CNS) pathologies, including mood disorders, neurodegenerative disorders, neurodevelopmental disorders, and addiction. Toll-like receptors (TLRs), a key component of the innate immune response, are particularly implicated in neuroimmune dysfunction. However, most of our understanding about TLR signaling comes from the peripheral immune response, and it is becoming clear that the CNS immune response is unique. One controversial aspect of neuroimmune signaling is which CNS cell types are involved. While microglia are the CNS cell-type derived from a myeloid lineage, studies suggest that other glial cell types and even neurons express TLRs, although this idea is controversial. Furthermore, recent work suggests a discrepancy between RNA and protein expression within the CNS. Methods: To elucidate the CNS cell-type localization of TLRs and their downstream signaling molecules, we isolated microglia and astrocytes from the brain of adult mice treated with saline or the TLR4 ligand lipopolysaccharide (LPS). Glial mRNA and protein expression was compared to a cellular-admixture to determine cell-type enrichment. Results: Enrichment analysis revealed that most of the TLR pathway genes are localized in microglia and changed in microglia following immune challenge. However, expression of
Tlr3 was enriched in astrocytes, where it increased in response to LPS. Furthermore, attempts to determine protein cell-type localization revealed that many antibodies are non-specific and that antibody differences are contributing to conflicting localization results. Conclusions: Together these results highlight the cell types that should be looked at when studying TLR signaling gene expression and suggest that non-antibody approaches need to be used to accurately evaluate protein expression.
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Affiliation(s)
- Gizelle M McCarthy
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.,Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, 78712, USA
| | - Courtney R Bridges
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, 78712, USA
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, 78712, USA
| | - R Adron Harris
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.,Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, 78712, USA.,Insitute for Neuroscience, University of Texas at Austin, Austin, TX, 78712, USA
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74
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Martin E, El-Behi M, Fontaine B, Delarasse C. Analysis of Microglia and Monocyte-derived Macrophages from the Central Nervous System by Flow Cytometry. J Vis Exp 2017. [PMID: 28671658 DOI: 10.3791/55781] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Numerous studies have demonstrated the role of immune cells, in particular macrophages, in central nervous system (CNS) pathologies. There are two main macrophage populations in the CNS: (i) the microglia, which are the resident macrophages of the CNS and are derived from yolk sac progenitors during embryogenesis, and (ii) the monocyte-derived macrophages (MDM), which can infiltrate the CNS during disease and are derived from bone marrow progenitors. The roles of each macrophage subpopulation differ depending on the pathology being studied. Furthermore, there is no consensus on the histological markers or the distinguishing criteria used for these macrophage subpopulations. However, the analysis of the expression profiles of the CD11b and CD45 markers by flow cytometry allows us to distinguish the microglia (CD11b+CD45med) from the MDM (CD11b+CD45high). In this protocol, we show that the density gradient centrifugation and the flow cytometry analysis can be used to characterize these CNS macrophage subpopulations, and to study several markers of interest expressed by these cells as we recently published. Thus, this technique can further our understanding of the role of macrophages in mouse models of neurological diseases and can also be used to evaluate drug effects on these cells.
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Affiliation(s)
- Elodie Martin
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM
| | - Mohamed El-Behi
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM
| | - Bertrand Fontaine
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM; AP-HP, Hôpital de la Pitié Salpêtrière
| | - Cecile Delarasse
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM;
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75
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Developmental toxicant exposure in a mouse model of Alzheimer’s disease induces differential sex-associated microglial activation and increased susceptibility to amyloid accumulation. J Dev Orig Health Dis 2017; 8:493-501. [DOI: 10.1017/s2040174417000277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
As the resident macrophage of the central nervous system, microglia are thought to contribute to Alzheimer’s disease (AD) pathology through lack of neuroprotection. The role of immune dysfunction in AD may be due to disruption of regulatory signals for the activation of microglia that may occur early in development. We hypothesized that early toxicant exposure would systematically activate microglia, possibly reversing the pathological severity of AD. Offspring of a triple transgenic murine model for AD (3×TgAD) were exposed to a model neurotoxicant, lead acetate, from postnatal days (PND) 5–10. Our results indicated that female mice exposed to Pb had a greater and earlier incidence of amyloid burden within the hippocampus, coinciding with decreased markers of microglial activation at PND 50. Pb-exposed males had increased microglial activation at PND 50, as evidence by CD11b expression and microglial abundance, with no significant increase in amyloid burden at that time. There was greater amyloid burden at PND 90 and 180 in both male and female mice exposed to Pb compared with control. Together, these data suggest that activated microglia are neuroprotective against amyloid accumulation early in AD pathology, and that early exposure to Pb could increase susceptibility to later-life neurodegeneration. Likewise, females may be more susceptible to early-life microglial damage, and, subsequently, AD. Further investigation into the sex biased mechanisms by which microglial activation is altered by an early-life immune insult will provide critical insight into the temporal susceptibility of the developing neuroimmune system and its potential role in AD etiopathology.
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76
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Brooks AK, Janda TM, Lawson MA, Rytych JL, Smith RA, Ocampo-Solis C, McCusker RH. Desipramine decreases expression of human and murine indoleamine-2,3-dioxygenases. Brain Behav Immun 2017; 62:219-229. [PMID: 28212884 PMCID: PMC5382643 DOI: 10.1016/j.bbi.2017.02.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/01/2017] [Accepted: 02/13/2017] [Indexed: 12/13/2022] Open
Abstract
Abundant evidence connects depression symptomology with immune system activation, stress and subsequently elevated levels of kynurenine. Anti-depressants, such as the tricyclic norepinephrine/serotonin reuptake inhibitor desipramine (Desip), were developed under the premise that increasing extracellular neurotransmitter level was the sole mechanism by which they alleviate depressive symptomologies. However, evidence suggests that anti-depressants have additional actions that contribute to their therapeutic potential. The Kynurenine Pathway produces tryptophan metabolites that modulate neurotransmitter activity. This recognition identified another putative pathway for anti-depressant targeting. Considering a recognized role of the Kynurenine Pathway in depression, we investigated the potential for Desip to alter expression of rate-limiting enzymes of this pathway: indoleamine-2,3-dioxygenases (Ido1 and Ido2). Mice were administered lipopolysaccharide (LPS) or synthetic glucocorticoid dexamethasone (Dex) with Desip to determine if Desip alters indoleamine-dioxygenase (DO) expression in vivo following a modeled immune and stress response. This work was followed by treating murine and human peripheral blood mononuclear cells (PBMCs) with interferon-gamma (IFNγ) and Desip. In vivo: Desip blocked LPS-induced Ido1 expression in hippocampi, astrocytes, microglia and PBMCs and Ido2 expression by PBMCs. Ex vivo: Desip decreased IFNγ-induced Ido1 and Ido2 expression in murine PBMCs. This effect was directly translatable to the human system as Desip decreased IDO1 and IDO2 expression by human PBMCs. These data demonstrate for the first time that an anti-depressant alters expression of Ido1 and Ido2, identifying a possible new mechanism behind anti-depressant activity. Furthermore, we propose the assessment of PBMCs for anti-depressant responsiveness using IDO expression as a biomarker.
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Affiliation(s)
- Alexandra K Brooks
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
| | - Tiffany M Janda
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
| | - Marcus A Lawson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
| | - Jennifer L Rytych
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
| | - Robin A Smith
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
| | - Cecilia Ocampo-Solis
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
| | - Robert H McCusker
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Pathology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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77
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Arifuzzaman S, Das A, Kim SH, Yoon T, Lee YS, Jung KH, Chai YG. Selective inhibition of EZH2 by a small molecule inhibitor regulates microglial gene expression essential for inflammation. Biochem Pharmacol 2017; 137:61-80. [PMID: 28431938 DOI: 10.1016/j.bcp.2017.04.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 04/13/2017] [Indexed: 12/15/2022]
Abstract
Multiple studies have documented that Enhancer of zeste homolog 2 (EZH2) could play a role in inflammation and a wide range of malignancies; however, the underlying mechanisms remain largely unaddressed. Microglial activation is a key process in the production and release of numerous pro-inflammatory mediators that play important roles in inflammation and neurodegeneration in the central nervous system (CNS). Therefore, our aim was to investigate whether inhibition of EZH2 with the selective small molecule inhibitor EPZ-6438 protects against neonatal microglial activation. First, in mouse primary microglial cells and a microglial cell line, we found that LPS can rapidly increase EZH2 mRNA level and we subsequently performed gene expression profiling and constructed networks in resting, EPZ-6438-treated, LPS-treated and LPS+EPZ-6438-treated primary microglial cells and a microglial cell line using transcriptome RNA sequencing and bioinformatics analyses. By examining the RNA sequencing, we identified EPZ-6438 target genes and co-regulated modules that were critical for inflammation. We also identified unexpected relationships between the inducible transcription factors (TFs), motif strength, and the transcription of key inflammatory mediators. Furthermore, we showed that EPZ-6438 controls important inflammatory gene targets by modulating interferon regulatory factor (IRF) 1, IRF8, and signal transducer and activator of transcription (STAT) 1 levels at their promoter sites. Our unprecedented findings demonstrate that pharmacological interventions built upon EZH2 inhibition by EPZ-6438 could be a useful therapeutic approach for the treatment of neuroinflammatory diseases associated with microglial activation.
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Affiliation(s)
- Sarder Arifuzzaman
- Department of Bionanotechnology, Hanyang University, Seoul 04673, Republic of Korea.
| | - Amitabh Das
- Institute of Natural Science & Technology, Hanyang University, Ansan 15588, Republic of Korea.
| | - Sun Hwa Kim
- Department of Molecular & Life Sciences, Hanyang University, Ansan 15588, Republic of Korea.
| | - Taeho Yoon
- Department of Molecular & Life Sciences, Hanyang University, Ansan 15588, Republic of Korea.
| | - Young Seek Lee
- Department of Molecular & Life Sciences, Hanyang University, Ansan 15588, Republic of Korea.
| | - Kyoung Hwa Jung
- Institute of Natural Science & Technology, Hanyang University, Ansan 15588, Republic of Korea.
| | - Young Gyu Chai
- Department of Bionanotechnology, Hanyang University, Seoul 04673, Republic of Korea; Department of Molecular & Life Sciences, Hanyang University, Ansan 15588, Republic of Korea.
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78
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Pulido-Salgado M, Vidal-Taboada JM, Garcia Diaz-Barriga G, Serratosa J, Valente T, Castillo P, Matalonga J, Straccia M, Canals JM, Valledor A, Solà C, Saura J. Myeloid C/EBPβ deficiency reshapes microglial gene expression and is protective in experimental autoimmune encephalomyelitis. J Neuroinflammation 2017; 14:54. [PMID: 28302135 PMCID: PMC5356255 DOI: 10.1186/s12974-017-0834-5] [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] [Received: 11/11/2016] [Accepted: 03/06/2017] [Indexed: 12/31/2022] Open
Abstract
Background CCAAT/enhancer binding protein β (C/EBPβ) is a transcription factor that regulates the expression of important pro-inflammatory genes in microglia. Mice deficient for C/EBPβ show protection against excitotoxic and ischemic CNS damage, but the involvement in this neuroprotective effect of the various C/EBPβ-expressing cell types is not solved. Since C/EBPβ-deficient microglia show attenuated neurotoxicity in culture, we hypothesized that specific C/EBPβ deficiency in microglia could be neuroprotective in vivo. In this study, we have tested this hypothesis by generating mice with myeloid C/EBPβ deficiency. Methods Mice with myeloid C/EBPβ deficiency were generated by crossing LysMCre and C/EBPβfl/fl mice. Primary microglial cultures from C/EBPβfl/fl and LysMCre-C/EBPβfl/fl mice were treated with lipopolysaccharide ± interferon γ (IFNγ) for 6 h, and gene expression was analyzed by RNA sequencing. Gene expression and C/EBPβ deletion were analyzed in vivo in microglia isolated from the brains of C/EBPβfl/fl and LysMCre-C/EBPβfl/fl mice treated systemically with lipolysaccharide or vehicle. Mice of LysMCre-C/EBPβfl/fl or control genotypes were subjected to experimental autoimmune encephalitis and analyzed for clinical signs for 52 days. One- or two-way ANOVA or Kruskal–Wallis with their appropriate post hoc tests were used. Results LysMCre-C/EBPβfl/fl mice showed an efficiency of C/EBPβ deletion in microglia of 100 and 90% in vitro and in vivo, respectively. These mice were devoid of female infertility, perinatal mortality and reduced lifespan that are associated to full C/EBPβ deficiency. Transcriptomic analysis of C/EBPβ-deficient primary microglia revealed C/EBPβ-dependent expression of 1068 genes, significantly enriched in inflammatory and innate immune responses GO terms. In vivo, microglial expression of the pro-inflammatory genes Cybb, Ptges, Il23a, Tnf and Csf3 induced by systemic lipopolysaccharide injection was also blunted by C/EBPβ deletion. CNS expression of C/EBPβ was upregulated in experimental autoimmune encephalitis and in multiple sclerosis samples. Finally, LysMCre-C/EBPβfl/fl mice showed robust attenuation of clinical signs in experimental autoimmune encephalitis. Conclusion This study provides new data that support a central role for C/EBPβ in the biology of activated microglia, and it offers proof of concept for the therapeutic potential of microglial C/EBPβ inhibition in multiple sclerosis. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0834-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marta Pulido-Salgado
- Department of Biomedicine, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Jose M Vidal-Taboada
- Department of Biomedicine, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Gerardo Garcia Diaz-Barriga
- Department of Biomedicine, Histology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Joan Serratosa
- Department of Cerebral Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona, CSIC, IDIBAPS, Barcelona, Spain
| | - Tony Valente
- Department of Biomedicine, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Department of Cerebral Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona, CSIC, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Paola Castillo
- Department of Pathology, Hospital Clinic, ISGlobal, CRESIB, Barcelona, Spain
| | - Jonathan Matalonga
- Department of Physiology and Immunology, School of Biology, University of Barcelona, Barcelona, Catalonia, Spain
| | - Marco Straccia
- Department of Biomedicine, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Department of Biomedicine, Histology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Department of Cerebral Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona, CSIC, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Josep M Canals
- Department of Biomedicine, Histology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Annabel Valledor
- Department of Physiology and Immunology, School of Biology, University of Barcelona, Barcelona, Catalonia, Spain
| | - Carme Solà
- Department of Cerebral Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona, CSIC, IDIBAPS, Barcelona, Spain
| | - Josep Saura
- Department of Biomedicine, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain. .,Institute of Neurosciences, University of Barcelona, Barcelona, Spain.
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79
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Faust A, Kandakatla A, van der Merwe Y, Ren T, Huleihel L, Hussey G, Naranjo JD, Johnson S, Badylak S, Steketee M. Urinary bladder extracellular matrix hydrogels and matrix-bound vesicles differentially regulate central nervous system neuron viability and axon growth and branching. J Biomater Appl 2017; 31:1277-1295. [PMID: 28447547 DOI: 10.1177/0885328217698062] [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: 01/13/2023]
Abstract
Central nervous system neurons often degenerate after trauma due to the inflammatory innate immune response to injury, which can lead to neuronal cell death, scarring, and permanently lost neurologic function. Extracellular matrix bioscaffolds, derived by decellularizing healthy tissues, have been widely used in both preclinical and clinical studies to promote positive tissue remodeling, including neurogenesis, in numerous tissues, with extracellular matrix from homologous tissues often inducing more positive responses. Extracellular matrix hydrogels are liquid at room temperature and enable minimally invasive extracellular matrix injections into central nervous system tissues, before gelation at 37℃. However, few studies have analyzed how extracellular matrix hydrogels influence primary central nervous system neuron survival and growth, and whether central nervous system and non-central nervous system extracellular matrix specificity is critical to neuronal responses. Urinary bladder extracellular matrix hydrogels increase both primary hippocampal neuron survival and neurite growth to similar or even greater extents, suggesting extracellular matrix from non-homologous tissue sources, such as urinary bladder matrix-extracellular matrix, may be a more economical and safer alternative to developing central nervous system extracellular matrices for central nervous system applications. Additionally, we show matrix-bound vesicles derived from urinary bladder extracellular matrix are endocytosed by hippocampal neurons and positively regulate primary hippocampal neuron neurite growth. Matrix-bound vesicles carry protein and RNA cargos, including noncoding RNAs and miRNAs that map to the human genome and are known to regulate cellular processes. Thus, urinary bladder matrix-bound vesicles provide natural and transfectable cargoes which offer new experimental tools and therapeutic applications to study and treat central nervous system neuron injury.
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Affiliation(s)
- Anne Faust
- 1 Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA
| | - Apoorva Kandakatla
- 1 Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA
| | - Yolandi van der Merwe
- 1 Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,3 Swanson School of Engineering, Department of Bioengineering University of Pittsburgh, Pittsburgh, PA, USA
| | - Tanchen Ren
- 1 Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA
| | - Luai Huleihel
- 2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,4 Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - George Hussey
- 2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,4 Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Juan Diego Naranjo
- 2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,4 Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Scott Johnson
- 2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,4 Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen Badylak
- 2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,4 Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Steketee
- 1 Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,2 McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.,5 Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
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80
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Matrix Metalloproteinase Activity in Infections by an Encephalitic Virus, Mouse Adenovirus Type 1. J Virol 2017; 91:JVI.01412-16. [PMID: 28053109 DOI: 10.1128/jvi.01412-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 12/24/2016] [Indexed: 12/17/2022] Open
Abstract
Mouse adenovirus type 1 (MAV-1) infection causes encephalitis in susceptible strains of mice and alters the permeability of infected brains to small molecules, which indicates disruption of the blood-brain barrier (BBB). Under pathological conditions, matrix metalloproteinases (MMPs) can disrupt the BBB through their proteolytic activity on basement membrane and tight junction proteins. We examined whether MAV-1 infection alters MMP activity in vivo and in vitro Infected MAV-1-susceptible SJL mice had higher MMP2 and MMP9 activity in brains, measured by gelatin zymography, than mock-infected mice. Infected MAV-1-resistant BALB/c mice had MMP activity levels equivalent to those in mock infection. Primary SJL mouse brain endothelial cells (a target of MAV-1 in vivo) infected ex vivo with MAV-1 had no difference in activities of secreted MMP2 and MMP9 from mock cells. We show for the first time that astrocytes and microglia are also infected in vivo by MAV-1. Infected mixed primary cultures of astrocytes and microglia had higher levels of MMP2 and MMP9 activity than mock-infected cells. These results indicate that increased MMP activity in the brains of MAV-1-infected susceptible mice may be due to MMP activity produced by endothelial cells, astrocytes, and microglia, which in turn may contribute to BBB disruption and encephalitis in susceptible mice.IMPORTANCE RNA and DNA viruses can cause encephalitis; in some cases, this is accompanied by MMP-mediated disruption of the BBB. Activated MMPs degrade extracellular matrix and cleave tight-junction proteins and cytokines, modulating their functions. MAV-1 infection of susceptible mice is a tractable small-animal model for encephalitis, and the virus causes disruption of the BBB. We showed that MAV-1 infection increases enzymatic activity of two key MMPs known to be secreted and activated in neuroinflammation, MMP2 and MMP9, in brains of susceptible mice. MAV-1 infects endothelial cells, astrocytes, and microglia, cell types in the neurovascular unit that can secrete MMPs. Ex vivo MAV-1 infection of these cell types caused higher MMP activity than mock infection, suggesting that they may contribute to the higher MMP activity seen in vivo To our knowledge, this provides the first evidence of an encephalitic DNA virus in its natural host causing increased MMP activity in brains.
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Dorfman MD, Krull JE, Douglass JD, Fasnacht R, Lara-Lince F, Meek TH, Shi X, Damian V, Nguyen HT, Matsen ME, Morton GJ, Thaler JP. Sex differences in microglial CX3CR1 signalling determine obesity susceptibility in mice. Nat Commun 2017; 8:14556. [PMID: 28223698 PMCID: PMC5322503 DOI: 10.1038/ncomms14556] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 01/12/2017] [Indexed: 02/06/2023] Open
Abstract
Female mice are less susceptible to the negative metabolic consequences of high-fat diet feeding than male mice, for reasons that are incompletely understood. Here we identify sex-specific differences in hypothalamic microglial activation via the CX3CL1-CX3CR1 pathway that mediate the resistance of female mice to diet-induced obesity. Female mice fed a high-fat diet maintain CX3CL1-CX3CR1 levels while male mice show reductions in both ligand and receptor expression. Female Cx3cr1 knockout mice develop 'male-like' hypothalamic microglial accumulation and activation, accompanied by a marked increase in their susceptibility to diet-induced obesity. Conversely, increasing brain CX3CL1 levels in male mice through central pharmacological administration or virally mediated hypothalamic overexpression converts them to a 'female-like' metabolic phenotype with reduced microglial activation and body-weight gain. These data implicate sex differences in microglial activation in the modulation of energy homeostasis and identify CX3CR1 signalling as a potential therapeutic target for the treatment of obesity.
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Affiliation(s)
- Mauricio D. Dorfman
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Jordan E. Krull
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - John D. Douglass
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Rachael Fasnacht
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Fernando Lara-Lince
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Thomas H. Meek
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Xiaogang Shi
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Vincent Damian
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Hong T. Nguyen
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Miles E. Matsen
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Gregory J. Morton
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Joshua P. Thaler
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
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82
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Tran DQ, Tse EK, Kim MH, Belsham DD. Diet-induced cellular neuroinflammation in the hypothalamus: Mechanistic insights from investigation of neurons and microglia. Mol Cell Endocrinol 2016; 438:18-26. [PMID: 27208620 DOI: 10.1016/j.mce.2016.05.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/17/2016] [Indexed: 12/31/2022]
Abstract
Diet-induced obesity can lead to detrimental chronic disorders. The severity of this global epidemic has encouraged ongoing research to characterize the mechanisms underlying obesity and its comorbidities. Recent evidence suggests that saturated fatty acids (SFA) in high-fat diets rapidly generate inflammation in the arcuate nucleus of the hypothalamus (ARC), which centrally regulates whole-body energy homeostasis. Herein, we will review the roles of hypothalamic neurons and resident microglia in the initiation of SFA-induced hypothalamic inflammation. Particularly, we focus on neuronal and microglial free fatty acid-sensing and capacity to produce inflammatory signaling. We also outline a potential role of peripherally-derived monocytes in this inflammation. And finally, we explore synaptic plasticity as a mechanism through which hypothalamic inflammation can modulate ARC circuitry, and thus disrupt energy homeostasis.
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Affiliation(s)
- Dean Q Tran
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Erika K Tse
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Mun Heui Kim
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Denise D Belsham
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
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83
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Baik SH, Kang S, Son SM, Mook-Jung I. Microglia contributes to plaque growth by cell death due to uptake of amyloid β in the brain of Alzheimer's disease mouse model. Glia 2016; 64:2274-2290. [PMID: 27658617 DOI: 10.1002/glia.23074] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/24/2016] [Accepted: 09/09/2016] [Indexed: 11/09/2022]
Abstract
Pathological hallmarks of Alzheimer's disease (AD) include extracellularly accumulated amyloid β (Aβ) plaques and intracellular neurofibrillary tangles in the brain. Activated microglia, brain-resident macrophages, are also found surrounding Aβ plaques. The study of the brain of AD mouse models revealed that Aβ plaque formation is completed by the consolidation of newly generated plaque clusters in vicinity of existed plaques. However, the dynamics of Aβ plaque formation, growth and the mechanisms by which microglia contribute to Aβ plaque formation are unknown. In the present study, we confirmed how microglia are involved in Aβ plaque formation and their growth in the brain of 5XFAD mice, the Aβ-overexpressing AD transgenic mouse model, and performed serial intravital two-photon microscopy (TPM) imaging of the brains of 5XFAD mice crossed with macrophage/microglia-specific GFP-expressing CX3CR1GFP/GFP mice. We found that activated microglia surrounding Aβ plaques take up Aβ, which are clusters developed inside activated microglia in vivo and this was followed by microglial cell death. These dying microglia release the accumulated Aβ into the extracellular space, which contributes to Aβ plaque growth. This process was confirmed by live TPM in vivo imaging and flow cytometry. These results suggest that activated microglia can contribute to formation and growth of Aβ plaques by causing microglial cell death in the brain. GLIA 2016;64:2274-2290.
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Affiliation(s)
- Sung Hoon Baik
- Department of Biochemistry and Biomedical Sciences, Seoul National University, College of Medicine, 103 Daehak-ro, Jongro-gu, Seoul, 110-799, South Korea
| | - Seokjo Kang
- Department of Biochemistry and Biomedical Sciences, Seoul National University, College of Medicine, 103 Daehak-ro, Jongro-gu, Seoul, 110-799, South Korea
| | - Sung Min Son
- Department of Biochemistry and Biomedical Sciences, Seoul National University, College of Medicine, 103 Daehak-ro, Jongro-gu, Seoul, 110-799, South Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical Sciences, Seoul National University, College of Medicine, 103 Daehak-ro, Jongro-gu, Seoul, 110-799, South Korea.
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84
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Korvers L, de Andrade Costa A, Mersch M, Matyash V, Kettenmann H, Semtner M. Spontaneous Ca 2+ transients in mouse microglia. Cell Calcium 2016; 60:396-406. [PMID: 27697289 DOI: 10.1016/j.ceca.2016.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 02/07/2023]
Abstract
Microglia are the resident immune cells in the central nervous system and many of their physiological functions are known to be linked to intracellular calcium (Ca2+) signaling. Here we show that isolated and purified mouse microglia-either freshly or cultured-display spontaneous and transient Ca2+ elevations lasting for around ten to twenty seconds and occurring at frequencies of around five to ten events per hour and cell. The events were absent after depletion of internal Ca2+ stores, by phospholipase C (PLC) inhibition or blockade of inositol-1,4,5-trisphosphate receptors (IP3Rs), but not by removal of extracellular Ca2+, indicating that Ca2+ is released from endoplasmic reticulum intracellular stores. We furthermore provide evidence that autocrine ATP release and subsequent activation of purinergic P2Y receptors is not the trigger for these events. Spontaneous Ca2+ transients did also occur after stimulation with Lipopolysaccharide (LPS) and in glioma-associated microglia, but their kinetics differed from control conditions. We hypothesize that spontaneous Ca2+ transients reflect aspects of cellular homeostasis that are linked to regular and patho-physiological functions of microglia.
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Affiliation(s)
- Laura Korvers
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Amanda de Andrade Costa
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Martin Mersch
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Vitali Matyash
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Helmut Kettenmann
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Marcus Semtner
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany.
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FK506 Attenuates the Inflammation in Rat Spinal Cord Injury by Inhibiting the Activation of NF-κB in Microglia Cells. Cell Mol Neurobiol 2016; 37:843-855. [DOI: 10.1007/s10571-016-0422-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 08/23/2016] [Indexed: 02/08/2023]
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86
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Matt SM, Lawson MA, Johnson RW. Aging and peripheral lipopolysaccharide can modulate epigenetic regulators and decrease IL-1β promoter DNA methylation in microglia. Neurobiol Aging 2016; 47:1-9. [PMID: 27500965 DOI: 10.1016/j.neurobiolaging.2016.07.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 07/01/2016] [Accepted: 07/07/2016] [Indexed: 12/23/2022]
Abstract
In aged mice, peripheral stimulation of the innate immune system with lipopolysaccharide (LPS) causes exaggerated neuroinflammation and prolonged sickness behavior due in part to microglial dysfunction. Epigenetic changes to DNA may play a role in microglial dysfunction; therefore, we sought to determine whether aged microglia displayed DNA hypomethylation of the interleukin-1 beta (IL-1β) promoter and altered expression of epigenetic regulators. We further examined whether the demethylating agent 5-azacytidine induced IL-1β expression in BV2 and primary microglia similar to microglia from aged mice. Novel findings indicated that aged mice had decreased methylation of the IL-1β gene promoter in primary microglia basally or following systemic LPS that is associated with increased IL-1β mRNA, intracellular IL-1β production, as well as prolonged sickness behavior. Last, 5-azacytidine increased IL-1β gene expression and decreased DNA methylation of BV2 and primary microglial cells similar to microglia from aged mice. Taken together, these data indicate that DNA methylation promotes heightened microglial activation in the aged brain.
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Affiliation(s)
- Stephanie M Matt
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Marcus A Lawson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Rodney W Johnson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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87
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Gonzalez-Pena D, Nixon SE, Southey BR, Lawson MA, McCusker RH, Hernandez AG, Dantzer R, Kelley KW, Rodriguez-Zas SL. Differential Transcriptome Networks between IDO1-Knockout and Wild-Type Mice in Brain Microglia and Macrophages. PLoS One 2016; 11:e0157727. [PMID: 27314674 PMCID: PMC4912085 DOI: 10.1371/journal.pone.0157727] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 05/06/2016] [Indexed: 11/19/2022] Open
Abstract
Microglia in the brain and macrophages in peripheral organs are cell types responsible for immune response to challenges. Indoleamine 2,3-dioxygenase 1 (IDO1) is an immunomodulatory enzyme of the tryptophan pathway that is expressed in the brain. The higher activity of IDO1 in response to immune challenge has been implicated in behavioral disorders. The impact of IDO1 depletion on the microglia transcriptome has not been studied. An investigation of the transcript networks in the brain microglia from IDO1-knockout (IDO1-KO) mice was undertaken, relative to peripheral macrophages and to wild-type (WT) mice under unchallenged conditions. Over 105 transcript isoforms were differentially expressed between WT and IDO1-KO within cell type. Within microglia, Saa3 and Irg1 were over-expressed in IDO1-KO relative to WT. Within macrophages, Csf3 and Sele were over-expressed in IDO1-KO relative to WT. Among the genes differentially expressed between strains, enriched biological processes included ion homeostasis and ensheathment of neurons within microglia, and cytokine and chemokine expression within macrophages. Over 11,110 transcript isoforms were differentially expressed between microglia and macrophages and of these, over 10,800 transcripts overlapped between strains. Enriched biological processes among the genes over- and under-expressed in microglia relative to macrophages included cell adhesion and apoptosis, respectively. Detected only in microglia or macrophages were 421 and 43 transcript isoforms, respectively. Alternative splicing between cell types based on differential transcript isoform abundance was detected in 210 genes including Phf11d, H2afy, and Abr. Across strains, networks depicted a predominance of genes under-expressed in microglia relative to macrophages that may be a precursor for the different response of both cell types to challenges. The detected transcriptome differences enhance the understanding of the role of IDO1 in the microglia transcriptome under unchallenged conditions.
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Affiliation(s)
- Dianelys Gonzalez-Pena
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Scott E. Nixon
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Bruce R. Southey
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Marcus A. Lawson
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Robert H. McCusker
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Alvaro G. Hernandez
- Department of Symptom Research, University of Texas M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Robert Dantzer
- High-Throughput Sequencing and Genotyping Unit, Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Keith W. Kelley
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Sandra L. Rodriguez-Zas
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Statistics, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America
- Carle Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
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88
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Zhang L, Huang Y, Lin Y, Shan Y, Tan S, Cai W, Li H, Zhang B, Men X, Lu Z. Anti-inflammatory effect of cholera toxin B subunit in experimental stroke. J Neuroinflammation 2016; 13:147. [PMID: 27296014 PMCID: PMC4906956 DOI: 10.1186/s12974-016-0610-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/02/2016] [Indexed: 12/20/2022] Open
Abstract
Background Cholera toxin B subunit (CTB) has multifaceted immunoregulatory functions. Immunity plays an important role in the mechanism of stroke. However, little is known about whether CTB is beneficial for stroke. Methods CTB was administered intraperitoneally after ischemia to rats subjected to transient focal ischemia. Infarct volumes, body weight loss, and neurologic deficits were measured. Cytokines, microglia/macrophage activation, and transcriptional factors in the ischemic brain were tested. The mRNA expressions of IL-1β and TNF-α were tested in the microglia/macrophage isolated from the ischemic hemisphere. γδT cells, IL-17-producing γδT cells, Th17 cells, and regulatory T (Treg) cells in the ischemic brain were tested. γδT cells and Treg cells in the peripheral blood were also evaluated. Results CTB reduced infarct volumes, neurologic deficits, and body weight loss after ischemia. At 24 h after ischemia, CTB downregulated the levels of IL-1β, TNF-α, NF-kB p65, phosphorylated-ERK1/2, and microglia/macrophage activation and suppressed NF-kB binding activity, but did not affect the level of ERK1/2. The mRNA expressions of IL-1β and TNF-α in the microglia/macrophage isolated from the ischemic hemisphere were suppressed after CTB therapy. In the ischemic hemisphere, CTB treatment reduced the levels of γδT cells, IL-17-producing γδT cells, and IL-17 at both 24 and 72 h after ischemia, while Th17 cells were not affected. After CTB treatment, the levels of Treg cells, TGF-β, and IL-10 remained unchanged at 24 h and upregulated at 72 h after ischemia. Inactivation of Treg cells using anti-CD25 attenuated the increase of TGF-β and IL-10 induced by CTB at 72 h after ischemia. In the peripheral blood, CTB increased Treg cells and suppressed γδT cells at 24 h after ischemia. And then at 72 h after ischemia, it increased Treg cells but did not impact γδT cells. CTB had no effect on cytokines, transcription factors, infiltrating γδT cells, and Treg cells in the brain of shams. In the peripheral blood of shams, CTB increased Treg cells at both 24 and 72 h, while it did not affect γδT cells. Conclusions CTB decreased neurologic impairment and tissue injury after cerebral ischemia via its immunomodulatory functions, including inhibiting microglia/macrophage activation, suppressing γδT cells, and inducing production of Treg cells, thus regulating the secretion of related cytokines. Suppression of NF-kB and ERK1/2 pathways is involved in the neuroprotective mechanism of CTB.
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Affiliation(s)
- Lei Zhang
- Department of Neurology, The Fifth Affiliated Hospital of Sun Yat-sen University, No. 52 Meihuadong Road, Zhuhai City, China.,Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Yanxia Huang
- Department of Neurology, The Fifth Affiliated Hospital of Sun Yat-sen University, No. 52 Meihuadong Road, Zhuhai City, China
| | - Yinyao Lin
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Yilong Shan
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Sha Tan
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Wei Cai
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Haiyan Li
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Bingjun Zhang
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Xuejiao Men
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China
| | - Zhengqi Lu
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, No. 600 Tianhe Road, Guangzhou City, China.
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89
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Ji P, Schachtschneider KM, Schook LB, Walker FR, Johnson RW. Peripheral viral infection induced microglial sensome genes and enhanced microglial cell activity in the hippocampus of neonatal piglets. Brain Behav Immun 2016; 54:243-251. [PMID: 26872419 PMCID: PMC4828316 DOI: 10.1016/j.bbi.2016.02.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 12/26/2022] Open
Abstract
Although poorly understood, early-life infection is predicted to affect brain microglial cells, making them hypersensitive to subsequent stimuli. To investigate this, we assessed gene expression in hippocampal tissue obtained from a previously published study reporting increased microglial cell activity and reduced hippocampal-dependent learning in neonatal piglets infected with porcine reproductive and respiratory syndrome virus (PRRSV), a virus that induces interstitial pneumonia. Infection altered expression of 455 genes, of which 334 were up-regulated and 121 were down-regulated. Functional annotation revealed that immune function genes were enriched among the up-regulated differentially expressed genes (DEGs), whereas calcium binding and synaptic vesicle genes were enriched among the down-regulated DEGs. Twenty-six genes encoding part of the microglia sensory apparatus (i.e., the sensome) were up-regulated (e.g., IL1R1, TLR2, and TLR4), whereas 15 genes associated with the synaptosome and synaptic receptors (e.g., NPTX2, GABRA2, and SLC5A7) were down-regulated. As the sensome may foretell microglia reactivity, we next inoculated piglets with culture medium or PRRSV at PD 7 and assessed hippocampal microglia morphology and function at PD 28 when signs of infection were waning. Consistent with amplification of the sensome, microglia from PRRSV piglets had enhanced responsiveness to chemoattractants, increased phagocytic activity, and secreted more TNFα in response to lipopolysaccharide and Poly I:C. Immunohistochemical staining indicated PRRSV infection increased microglia soma length and length-to-width ratio. Bipolar rod-like microglia not evident in hippocampus of control piglets, were present in infected piglets. Collectively, this study suggests early-life infection alters the microglia sensome as well as microglial cell morphology and function.
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Affiliation(s)
- Peng Ji
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
| | - Kyle M. Schachtschneider
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
,Animal Breeding and Genomics Center, Wageningen University, Wageningen, The Netherlands
| | - Lawrence B. Schook
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
,Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
| | - Frederick R. Walker
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, Australia
| | - Rodney W. Johnson
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
,Division of Nutritional Sciences, University of Illinois, Urbana, Illinois, USA
,To whom correspondence may be addressed: Tel: +1-217-333-2118;
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90
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Differential Activation of Infiltrating Monocyte-Derived Cells After Mild and Severe Traumatic Brain Injury. Shock 2016; 43:255-60. [PMID: 26091024 DOI: 10.1097/shk.0000000000000291] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Microglia are the resident innate immune cells of the brain. Although embryologically and functionally distinct, they are morphologically similar to peripheral monocyte-derived cells, resulting in a poor ability to discriminate between the two cell types. The purpose of this study was to develop a rapid and reliable method to simultaneously characterize, quantify, and discriminate between whole populations of myeloid cells from the brain in a murine model of traumatic brain injury. Male C57BL/6 mice underwent traumatic brain injury (n = 16) or sham injury (n = 14). Brains were harvested at 24 h after injury. Multiparameter flow cytometry and sequential gating analysis were performed, allowing for discrimination between microglia and infiltrating leukocytes as well as for the characterization and quantification of individual subtypes within the infiltrating population. The proportion of infiltrating leukocytes within the brain increased with the severity of injury, and the predominant cell types within the infiltrating population were monocyte derived (P = 0.01). In addition, the severity of injury altered the overall makeup of the infiltrating monocyte-derived cells. In conclusion, we describe a flow cytometry-based technique for gross discrimination between infiltrating leukocytes and microglia as well as the ability to simultaneously characterize and quantify individual myeloid subtypes and their maturation states within these populations.
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91
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Selective VIP Receptor Agonists Facilitate Immune Transformation for Dopaminergic Neuroprotection in MPTP-Intoxicated Mice. J Neurosci 2016; 35:16463-78. [PMID: 26674871 DOI: 10.1523/jneurosci.2131-15.2015] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
UNLABELLED Vasoactive intestinal peptide (VIP) mediates a broad range of biological responses by activating two related receptors, VIP receptor 1 and 2 (VIPR1 and VIPR2). Although the use of native VIP facilitates neuroprotection, clinical application of the hormone is limited due to VIP's rapid metabolism and inability to distinguish between VIPR1 and VIPR2 receptors. In addition, activation of both receptors by therapeutics may increase adverse secondary toxicities. Therefore, we developed metabolically stable and receptor-selective agonists for VIPR1 and VIPR2 to improve pharmacokinetic and pharmacodynamic therapeutic end points. Selective agonists were investigated for their abilities to protect mice against MPTP-induced neurodegeneration used to model Parkinson's disease (PD). Survival of tyrosine hydroxylase neurons in the substantia nigra was determined by stereological tests after MPTP intoxication in mice pretreated with either VIPR1 or VIPR2 agonist or after adoptive transfer of splenic cell populations from agonist-treated mice administered to MPTP-intoxicated animals. Treatment with VIPR2 agonist or splenocytes from agonist-treated mice resulted in increased neuronal sparing. Immunohistochemical tests showed that agonist-treated mice displayed reductions in microglial responses, with the most pronounced effects in VIPR2 agonist-treated, MPTP-intoxicated mice. In parallel studies, we observed reductions in proinflammatory cytokine release that included IL-17A, IL-6, and IFN-γ and increases in GM-CSF transcripts in CD4(+) T cells recovered from VIPR2 agonist-treated animals. Moreover, a phenotypic shift of effector to regulatory T cells was observed. These results support the use of VIPR2-selective agonists as neuroprotective agents for PD treatment. SIGNIFICANCE STATEMENT Vasoactive intestinal peptide receptor 2 can elicit immune transformation in a model of Parkinson's disease (PD). Such immunomodulatory capabilities can lead to neuroprotection by attenuating microglial activation and by slowing degradation of neuronal cell bodies and termini in MPTP-intoxicated mice. The protective mechanism arises from altering a Th1/Th2 immune cytokine response into an anti-inflammatory and neuronal sparing profile. These results are directly applicable for the development of novel PD therapies.
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92
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IL-33 ameliorates Alzheimer's disease-like pathology and cognitive decline. Proc Natl Acad Sci U S A 2016; 113:E2705-13. [PMID: 27091974 DOI: 10.1073/pnas.1604032113] [Citation(s) in RCA: 247] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Alzheimer's disease (AD) is a devastating condition with no known effective treatment. AD is characterized by memory loss as well as impaired locomotor ability, reasoning, and judgment. Emerging evidence suggests that the innate immune response plays a major role in the pathogenesis of AD. In AD, the accumulation of β-amyloid (Aβ) in the brain perturbs physiological functions of the brain, including synaptic and neuronal dysfunction, microglial activation, and neuronal loss. Serum levels of soluble ST2 (sST2), a decoy receptor for interleukin (IL)-33, increase in patients with mild cognitive impairment, suggesting that impaired IL-33/ST2 signaling may contribute to the pathogenesis of AD. Therefore, we investigated the potential therapeutic role of IL-33 in AD, using transgenic mouse models. Here we report that IL-33 administration reverses synaptic plasticity impairment and memory deficits in APP/PS1 mice. IL-33 administration reduces soluble Aβ levels and amyloid plaque deposition by promoting the recruitment and Aβ phagocytic activity of microglia; this is mediated by ST2/p38 signaling activation. Furthermore, IL-33 injection modulates the innate immune response by polarizing microglia/macrophages toward an antiinflammatory phenotype and reducing the expression of proinflammatory genes, including IL-1β, IL-6, and NLRP3, in the cortices of APP/PS1 mice. Collectively, our results demonstrate a potential therapeutic role for IL-33 in AD.
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Gonzalez-Pena D, Nixon SE, O’Connor JC, Southey BR, Lawson MA, McCusker RH, Borras T, Machuca D, Hernandez AG, Dantzer R, Kelley KW, Rodriguez-Zas SL. Microglia Transcriptome Changes in a Model of Depressive Behavior after Immune Challenge. PLoS One 2016; 11:e0150858. [PMID: 26959683 PMCID: PMC4784788 DOI: 10.1371/journal.pone.0150858] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/20/2016] [Indexed: 12/20/2022] Open
Abstract
Depression symptoms following immune response to a challenge have been reported after the recovery from sickness. A RNA-Seq study of the dysregulation of the microglia transcriptome in a model of inflammation-associated depressive behavior was undertaken. The transcriptome of microglia from mice at day 7 after Bacille Calmette Guérin (BCG) challenge was compared to that from unchallenged Control mice and to the transcriptome from peripheral macrophages from the same mice. Among the 562 and 3,851 genes differentially expressed between BCG-challenged and Control mice in microglia and macrophages respectively, 353 genes overlapped between these cells types. Among the most differentially expressed genes in the microglia, serum amyloid A3 (Saa3) and cell adhesion molecule 3 (Cadm3) were over-expressed and coiled-coil domain containing 162 (Ccdc162) and titin-cap (Tcap) were under-expressed in BCG-challenged relative to Control. Many of the differentially expressed genes between BCG-challenged and Control mice were associated with neurological disorders encompassing depression symptoms. Across cell types, S100 calcium binding protein A9 (S100A9), interleukin 1 beta (Il1b) and kynurenine 3-monooxygenase (Kmo) were differentially expressed between challenged and control mice. Immune response, chemotaxis, and chemokine activity were among the functional categories enriched by the differentially expressed genes. Functional categories enriched among the 9,117 genes differentially expressed between cell types included leukocyte regulation and activation, chemokine and cytokine activities, MAP kinase activity, and apoptosis. More than 200 genes exhibited alternative splicing events between cell types including WNK lysine deficient protein kinase 1 (Wnk1) and microtubule-actin crosslinking factor 1(Macf1). Network visualization revealed the capability of microglia to exhibit transcriptome dysregulation in response to immune challenge still after resolution of sickness symptoms, albeit lower than that observed in macrophages. The persistent transcriptome dysregulation in the microglia shared patterns with neurological disorders indicating that the associated persistent depressive symptoms share a common transcriptome basis.
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Affiliation(s)
- Dianelys Gonzalez-Pena
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Scott E. Nixon
- Illinois Informatics Institute, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Jason C. O’Connor
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Bruce R. Southey
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Marcus A. Lawson
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Robert H. McCusker
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Tania Borras
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Debbie Machuca
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
| | - Alvaro G. Hernandez
- High-Throughput Sequencing and Genotyping Unit, Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Champaign, IL, United States of America
| | - Robert Dantzer
- Department of Symptom Research, University of Texas M. D. Anderson Cancer Center, Houston, TX, United States of America
| | - Keith W. Kelley
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
- Integrative Immunology and Behavior Program and Department of Pathology, College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States of America
| | - Sandra L. Rodriguez-Zas
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States of America
- Department of Statistics and Carle Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States of America
- * E-mail:
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94
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Holt LM, Olsen ML. Novel Applications of Magnetic Cell Sorting to Analyze Cell-Type Specific Gene and Protein Expression in the Central Nervous System. PLoS One 2016; 11:e0150290. [PMID: 26919701 PMCID: PMC4769085 DOI: 10.1371/journal.pone.0150290] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 02/11/2016] [Indexed: 12/21/2022] Open
Abstract
The isolation and study of cell-specific populations in the central nervous system (CNS) has gained significant interest in the neuroscience community. The ability to examine cell-specific gene and protein expression patterns in healthy and pathological tissue is critical for our understanding of CNS function. Several techniques currently exist to isolate cell-specific populations, each having their own inherent advantages and shortcomings. Isolation of distinct cell populations using magnetic sorting is a technique which has been available for nearly 3 decades, although rarely used in adult whole CNS tissue homogenate. In the current study we demonstrate that distinct cell populations can be isolated in rodents from early postnatal development through adulthood. We found this technique to be amendable to customization using commercially available membrane-targeted antibodies, allowing for cell-specific isolation across development and animal species. This technique yields RNA which can be utilized for downstream applications—including quantitative PCR and RNA sequencing—at relatively low cost and without the need for specialized equipment or fluorescently labeled cells. Adding to its utility, we demonstrate that cells can be isolated largely intact, retaining their processes, enabling analysis of extrasomatic proteins. We propose that magnetic cell sorting will prove to be a highly useful technique for the examination of cell specific CNS populations.
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Affiliation(s)
- Leanne Melissa Holt
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Michelle Lynne Olsen
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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95
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Gabrusiewicz K, Rodriguez B, Wei J, Hashimoto Y, Healy LM, Maiti SN, Thomas G, Zhou S, Wang Q, Elakkad A, Liebelt BD, Yaghi NK, Ezhilarasan R, Huang N, Weinberg JS, Prabhu SS, Rao G, Sawaya R, Langford LA, Bruner JM, Fuller GN, Bar-Or A, Li W, Colen RR, Curran MA, Bhat KP, Antel JP, Cooper LJ, Sulman EP, Heimberger AB. Glioblastoma-infiltrated innate immune cells resemble M0 macrophage phenotype. JCI Insight 2016; 1:85841. [PMID: 26973881 DOI: 10.1172/jci.insight.85841] [Citation(s) in RCA: 320] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Glioblastomas are highly infiltrated by diverse immune cells, including microglia, macrophages, and myeloid-derived suppressor cells (MDSCs). Understanding the mechanisms by which glioblastoma-associated myeloid cells (GAMs) undergo metamorphosis into tumor-supportive cells, characterizing the heterogeneity of immune cell phenotypes within glioblastoma subtypes, and discovering new targets can help the design of new efficient immunotherapies. In this study, we performed a comprehensive battery of immune phenotyping, whole-genome microarray analysis, and microRNA expression profiling of GAMs with matched blood monocytes, healthy donor monocytes, normal brain microglia, nonpolarized M0 macrophages, and polarized M1, M2a, M2c macrophages. Glioblastoma patients had an elevated number of monocytes relative to healthy donors. Among CD11b+ cells, microglia and MDSCs constituted a higher percentage of GAMs than did macrophages. GAM profiling using flow cytometry studies revealed a continuum between the M1- and M2-like phenotype. Contrary to current dogma, GAMs exhibited distinct immunological functions, with the former aligned close to nonpolarized M0 macrophages.
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Affiliation(s)
- Konrad Gabrusiewicz
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Benjamin Rodriguez
- Division of Biostatistics, Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Jun Wei
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yuuri Hashimoto
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Luke M Healy
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | | | | | | | - Qianghu Wang
- Department of Bioinformatics and Computational Biology
| | | | - Brandon D Liebelt
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Nasser K Yaghi
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - Neal Huang
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jeffrey S Weinberg
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Sujit S Prabhu
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ganesh Rao
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Raymond Sawaya
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | | | | | - Amit Bar-Or
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Wei Li
- Division of Biostatistics, Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | | | | | - Krishna P Bhat
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jack P Antel
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | | | | | - Amy B Heimberger
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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96
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Abstract
The specific function of microglia, the tissue resident macrophages of the brain and spinal cord, has been difficult to ascertain because of a lack of tools to distinguish microglia from other immune cells, thereby limiting specific immunostaining, purification, and manipulation. Because of their unique developmental origins and predicted functions, the distinction of microglia from other myeloid cells is critically important for understanding brain development and disease; better tools would greatly facilitate studies of microglia function in the developing, adult, and injured CNS. Here, we identify transmembrane protein 119 (Tmem119), a cell-surface protein of unknown function, as a highly expressed microglia-specific marker in both mouse and human. We developed monoclonal antibodies to its intracellular and extracellular domains that enable the immunostaining of microglia in histological sections in healthy and diseased brains, as well as isolation of pure nonactivated microglia by FACS. Using our antibodies, we provide, to our knowledge, the first RNAseq profiles of highly pure mouse microglia during development and after an immune challenge. We used these to demonstrate that mouse microglia mature by the second postnatal week and to predict novel microglial functions. Together, we anticipate these resources will be valuable for the future study and understanding of microglia in health and disease.
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97
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Nikodemova M, Small AL, Kimyon RS, Watters JJ. Age-dependent differences in microglial responses to systemic inflammation are evident as early as middle age. Physiol Genomics 2016; 48:336-44. [PMID: 26884461 DOI: 10.1152/physiolgenomics.00129.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/10/2016] [Indexed: 01/17/2023] Open
Abstract
Whereas age increases microglial inflammatory activities and impairs their ability to effectively regulate their immune response, it is unclear at what age these exaggerated responses begin. We tested the hypotheses that augmented microglial responses to inflammatory challenge are present as early as middle age and that repeated stimulation of primed microglia in vivo would reveal microglial senescence. Microglial gene expression was investigated in a mouse model of repeated systemic inflammation induced by intraperitoneal injection of bacterial lipopolysaccharide (LPS). Following LPS, microglia from middle-aged mice (9-10 mo) displayed larger increases in Tnfα, Il-6, and Il-1β gene expression compared with young adults (2 mo). Similar results were observed in the spleens of middle-aged mice, indicating that exaggeration of both central and peripheral immune responses are already evident at early middle age. Interestingly, despite greater proinflammatory responses to the first LPS challenge in the aged mice, there were no age-dependent differences in either microglia or spleen following a subsequent LPS dose, suggesting that animals at this age retain the ability to effectively control their immune response following repeated challenge. The exacerbated microglial immune response to systemic inflammation at early middle age suggests that the CNS may be vulnerable to age-dependent alterations earlier than previously appreciated.
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Affiliation(s)
- Maria Nikodemova
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alissa L Small
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Rebecca S Kimyon
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
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98
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Rustenhoven J, Park TIH, Schweder P, Scotter J, Correia J, Smith AM, Gibbons HM, Oldfield RL, Bergin PS, Mee EW, Faull RLM, Curtis MA, Scott Graham E, Dragunow M. Isolation of highly enriched primary human microglia for functional studies. Sci Rep 2016; 6:19371. [PMID: 26778406 PMCID: PMC4725991 DOI: 10.1038/srep19371] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/10/2015] [Indexed: 11/30/2022] Open
Abstract
Microglia, the resident macrophages of the central nervous system play vital roles in brain homeostasis through clearance of pathogenic material. Microglia are also implicated in neurological disorders through uncontrolled activation and inflammatory responses. To date, the vast majority of microglial studies have been performed using rodent models. Human microglia differ from rodent counterparts in several aspects including their response to pharmacological substances and their inflammatory secretions. Such differences highlight the need for studies on primary adult human brain microglia and methods to isolate them are therefore required. Our procedure generates microglial cultures of >95% purity from both biopsy and autopsy human brain tissue using a very simple media-based culture procedure that takes advantage of the adherent properties of these cells. Microglia obtained in this manner can be utilised for research within a week. Isolated microglia demonstrate phagocytic ability and respond to inflammatory stimuli and their purity makes them suitable for numerous other forms of in vitro studies, including secretome and transcriptome analysis. Furthermore, this protocol allows for the simultaneous isolation of neural precursor cells during the microglial isolation procedure. As human brain tissue is such a precious and valuable resource the simultaneous isolation of multiple cell types is highly beneficial.
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Affiliation(s)
- Justin Rustenhoven
- Department of Pharmacology and Clinical Pharmacology, 1023, Auckland, New Zealand.,Centre for Brain Research, 1023, Auckland, New Zealand
| | - Thomas I-H Park
- Department of Pharmacology and Clinical Pharmacology, 1023, Auckland, New Zealand.,Centre for Brain Research, 1023, Auckland, New Zealand.,Department of Anatomy with Radiology, 1023, Auckland, New Zealand
| | - Patrick Schweder
- Centre for Brain Research, 1023, Auckland, New Zealand.,Auckland City Hospital, 1023, Auckland, New Zealand
| | - John Scotter
- Auckland City Hospital, 1023, Auckland, New Zealand
| | | | - Amy M Smith
- Centre for Brain Research, 1023, Auckland, New Zealand
| | | | | | - Peter S Bergin
- Centre for Brain Research, 1023, Auckland, New Zealand.,Auckland City Hospital, 1023, Auckland, New Zealand
| | - Edward W Mee
- Centre for Brain Research, 1023, Auckland, New Zealand.,Auckland City Hospital, 1023, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, 1023, Auckland, New Zealand.,Department of Anatomy with Radiology, 1023, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, 1023, Auckland, New Zealand.,Department of Anatomy with Radiology, 1023, Auckland, New Zealand
| | - E Scott Graham
- Department of Pharmacology and Clinical Pharmacology, 1023, Auckland, New Zealand.,Centre for Brain Research, 1023, Auckland, New Zealand
| | - Mike Dragunow
- Department of Pharmacology and Clinical Pharmacology, 1023, Auckland, New Zealand.,Centre for Brain Research, 1023, Auckland, New Zealand
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99
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Crain JM, Watters JJ. Microglial P2 Purinergic Receptor and Immunomodulatory Gene Transcripts Vary By Region, Sex, and Age in the Healthy Mouse CNS. ACTA ACUST UNITED AC 2015; 3. [PMID: 26949719 DOI: 10.4172/2329-8936.1000124] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Inflammatory damage in many neurodegenerative diseases is restricted to certain regions of the CNS, and while microglia have long been implicated in the pathology of many of these disorders, information comparing their gene expression in different CNS regions is lacking. Here we tested the hypothesis that the expression of purinergic receptors, estrogen receptors and other neuroprotective and pro-inflammatory genes differed among CNS regions in healthy mice. Because neurodegenerative diseases vary in incidence by sex and age, we also examined the regional distribution of these genes in male and female mice of four different ages between 21 days and 12 months. We postulated that pro-inflammatory gene expression would be higher in older animals, and lower in young adult females. We found that microglial gene expression differed across the CNS. Estrogen receptor alpha (Esr1) mRNA levels were often lower in microglia from the brainstem/spinal cord than from the cortex, whereas tumor necrosis factor alpha (Tnfα) expression was several times higher. In addition, the regional pattern of gene expression often changed with animal age; for example, no regional differences in P2X7 mRNA levels were detected in 21 day-old animals, but at 7 weeks and older, expression was highest in cerebellar microglia. Lastly, the expression of some genes was sexually dimorphic. In microglia from 12 month-old animals, mRNA levels of inducible nitric oxide synthase, but not Tnfα, were higher in females than males. These data suggest that microglial gene expression is not uniformly more pro-inflammatory in males or older animals. Moreover, microglia from CNS regions in which neuronal damage predominates in neurodegenerative disease do not generally express more pro-inflammatory genes than microglia from regions less frequently affected. This study provides an in-depth assessment of regional-, sex- and age-dependent differences in key microglial transcripts from the healthy mouse CNS.
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Affiliation(s)
- Jessica M Crain
- Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI 53706; Center for Women's Health Research, University of Wisconsin, Madison, WI 53706
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706; Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI 53706; Center for Women's Health Research, University of Wisconsin, Madison, WI 53706
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100
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High yield extraction of pure spinal motor neurons, astrocytes and microglia from single embryo and adult mouse spinal cord. Sci Rep 2015; 5:16763. [PMID: 26577180 PMCID: PMC4649473 DOI: 10.1038/srep16763] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 10/19/2015] [Indexed: 12/13/2022] Open
Abstract
Extraction of mouse spinal motor neurons from transgenic mouse embryos recapitulating some aspects of neurodegenerative diseases like amyotrophic lateral sclerosis has met with limited success. Furthermore, extraction and long-term culture of adult mouse spinal motor neurons and glia remain also challenging. We present here a protocol designed to extract and purify high yields of motor neurons and glia from individual spinal cords collected on embryos and adult (5-month-old) normal or transgenic mice. This method is based on mild digestion of tissue followed by gradient density separation allowing to obtain two millions motor neurons over 92% pure from one E14.5 single embryo and more than 30,000 from an adult mouse. These cells can be cultured more than 14 days in vitro at a density of 100,000 cells/cm(2) to maintain optimal viability. Functional astrocytes and microglia and small gamma motor neurons can be purified at the same time. This protocol will be a powerful and reliable method to obtain motor neurons and glia to better understand mechanisms underlying spinal cord diseases.
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