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Sample records for c13nj microglia cell

  1. Lysophosphatidic acid receptor activation affects the C13NJ microglia cell line proteome leading to alterations in glycolysis, motility, and cytoskeletal architecture

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    Bernhart, Eva; Kollroser, Manfred; Rechberger, Gerald; Reicher, Helga; Heinemann, Akos; Schratl, Petra; Hallström, Seth; Wintersperger, Andrea; Nusshold, Christoph; DeVaney, Trevor; Zorn-Pauly, Klaus; Malli, Roland; Graier, Wolfgang; Malle, Ernst; Sattler, Wolfgang

    2014-01-01

    Microglia, the immunocompetent cells of the CNS, are rapidly activated in response to injury and microglia migration towards and homing at damaged tissue plays a key role in CNS regeneration. Lysophosphatidic acid (LPA) is involved in signaling events evoking microglia responses through cognate G protein-coupled receptors. Here we show that human immortalized C13NJ microglia express LPA receptor subtypes LPA1, LPA2, and LPA3 on mRNA and protein level. LPA activation of C13NJ cells induced Rho and extracellular signal-regulated kinase activation and enhanced cellular ATP production. In addition, LPA induced process retraction, cell spreading, led to pronounced changes of the actin cytoskeleton and reduced cell motility, which could be reversed by inhibition of Rho activity. To get an indication about LPA-induced global alterations in protein expression patterns a 2-D DIGE/LC-ESI-MS proteomic approach was applied. On the proteome level the most prominent changes in response to LPA were observed for glycolytic enzymes and proteins regulating cell motility and/or cytoskeletal dynamics. The present findings suggest that naturally occurring LPA is a potent regulator of microglia biology. This might be of particular relevance in the pathophysiological context of neurodegenerative disorders where LPA concentrations can be significantly elevated in the CNS. PMID:19899077

  2. Effects of oxaliplatin and oleic acid Gc-protein-derived macrophage-activating factor on murine and human microglia.

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    Branca, Jacopo J V; Morucci, Gabriele; Malentacchi, Francesca; Gelmini, Stefania; Ruggiero, Marco; Pacini, Stefania

    2015-09-01

    The biological properties and characteristics of microglia in rodents have been widely described, but little is known about these features in human microglia. Several murine microglial cell lines are used to investigate neurodegenerative and neuroinflammatory conditions; however, the extrapolation of the results to human conditions is frequently met with criticism because of the possibility of species-specific differences. This study compares the effects of oxaliplatin and of oleic acid Gc-protein-derived macrophage-activating factor (OA-GcMAF) on two microglial cell lines, murine BV-2 cells and human C13NJ cells. Cell viability, cAMP levels, microglial activation, and vascular endothelial growth factor (VEGF) expression were evaluated. Our data demonstrate that oxaliplatin induced a significant decrease in cell viability in BV-2 and in C13NJ cells and that this effect was not reversed with OA-GcMAF treatment. The signal transduction pathway involving cAMP/VEGF was activated after treatment with oxaliplatin and/or OA-GcMAF in both cell lines. OA-GcMAF induced a significant increase in microglia activation, as evidenced by the expression of the B7-2 protein, in BV-2 as well as in C13NJ cells that was not associated with a concomitant increase in cell number. Furthermore, the effects of oxaliplatin and OA-GcMAF on coculture morphology and apoptosis were evaluated. Oxaliplatin-induced cell damage and apoptosis were nearly completely reversed by OA-GcMAF treatment in both BV-2/SH-SY5Y and C13NJ/SH-SY5Y cocultures. Our data show that murine and human microglia share common signal transduction pathways and activation mechanisms, suggesting that the murine BV-2 cell line may represent an excellent model for studying human microglia. © 2015 Wiley Periodicals, Inc.

  3. Anti-inflammatory effects of glaucocalyxin B in microglia cells

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    Ping Gan

    2015-05-01

    Full Text Available Over-activated microglia is involved in various kinds of neurodegenerative process including Parkinson, Alzheimer and HIV dementia. Suppression of microglial over activation has emerged as a novel strategy for treatment of neuroinflammation-based neurodegeneration. In the current study, anti-inflammatory and neuroprotective effects of the ent-kauranoid diterpenoids, which were isolated from the aerial parts of Rabdosia japonica (Burm. f. var. glaucocalyx (Maxim. Hara, were investigated in cultured microglia cells. Glaucocalyxin B (GLB, one of five ent-kauranoid diterpenoids, significantly decreased the generation of nitric oxide (NO, tumor necrosis factor (TNF-α, interleukin (IL-1β, cyclooxygenase (COX-2 and inducible nitric oxide synthase (iNOS in the lipopolysaccharide (LPS-activated microglia cells. In addition, GLB inhibited activation of nuclear factor-κB (NF-κB, p38 mitogen-activated protein kinase (MAPK and generation of reactive oxygen species (ROS in LPS-activated microglia cells. Furthermore, GLB strongly induced the expression of heme oxygenase (HO-1 in BV-2 microglia cells. Finally, GLB exhibited neuroprotective effect by preventing over-activated microglia induced neurotoxicity in a microglia/neuron co-culture model. Taken together, the present study demonstrated that the GLB possesses anti-nueroinflammatory activity, and might serve as a potential therapeutic agent for treating neuroinflammatory diseases.

  4. Benfotiamine upregulates antioxidative system in activated BV-2 microglia cells

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    Iva eBozic

    2015-09-01

    Full Text Available Chronic microglial activation and resulting sustained neuroinflammatory reaction are generally associated with neurodegeneration. Activated microglia acquires proinflammatory cellular profile that generates oxidative burst. Their persistent activation exacerbates inflammation, which damages healthy neurons via cytotoxic mediators, such as superoxide radical anion and nitric oxide. In our recent study, we have shown that benfotiamine (S-benzoylthiamine O-monophosphate possesses anti-inflammatory effects. Here, the effects of benfotiamine on the pro-oxidative component of activity of LPS-stimulated BV-2 cells were investigated. The activation of microglia was accompanied by upregulation of intracellular antioxidative defense, which was further promoted in the presence of benfotiamine. Namely, activated microglia exposed to non-cytotoxic doses of benfotiamine showed increased levels and activities of hydrogen peroxide- and superoxide-removing enzymes – catalase and glutathione system, and superoxide dismutase. In addition, benfotiamine showed the capacity to directly scavenge superoxide radical anion. As a consequence, benfotiamine suppressed the activation of microglia and provoked a decrease in NO and •O2- production and lipid peroxidation. In conclusion, benfotiamine might silence pro-oxidative activity of microglia to alleviate/prevent oxidative damage of neighboring CNS cells.

  5. Benfotiamine upregulates antioxidative system in activated BV-2 microglia cells.

    Science.gov (United States)

    Bozic, Iva; Savic, Danijela; Stevanovic, Ivana; Pekovic, Sanja; Nedeljkovic, Nadezda; Lavrnja, Irena

    2015-01-01

    Chronic microglial activation and resulting sustained neuroinflammatory reaction are generally associated with neurodegeneration. Activated microglia acquires proinflammatory cellular profile that generates oxidative burst. Their persistent activation exacerbates inflammation, which damages healthy neurons via cytotoxic mediators, such as superoxide radical anion and nitric oxide. In our recent study, we have shown that benfotiamine (S-benzoylthiamine O-monophosphate) possesses anti-inflammatory effects. Here, the effects of benfotiamine on the pro-oxidative component of activity of LPS-stimulated BV-2 cells were investigated. The activation of microglia was accompanied by upregulation of intracellular antioxidative defense, which was further promoted in the presence of benfotiamine. Namely, activated microglia exposed to non-cytotoxic doses of benfotiamine showed increased levels and activities of hydrogen peroxide- and superoxide-removing enzymes-catalase and glutathione system, and superoxide dismutase. In addition, benfotiamine showed the capacity to directly scavenge superoxide radical anion. As a consequence, benfotiamine suppressed the activation of microglia and provoked a decrease in NO and (·)O(-) 2 production and lipid peroxidation. In conclusion, benfotiamine might silence pro-oxidative activity of microglia to alleviate/prevent oxidative damage of neighboring CNS cells.

  6. Directed Differentiation of Human Pluripotent Stem Cells to Microglia

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    Panagiotis Douvaras

    2017-06-01

    Full Text Available Microglia, the immune cells of the brain, are crucial to proper development and maintenance of the CNS, and their involvement in numerous neurological disorders is increasingly being recognized. To improve our understanding of human microglial biology, we devised a chemically defined protocol to generate human microglia from pluripotent stem cells. Myeloid progenitors expressing CD14/CX3CR1 were generated within 30 days of differentiation from both embryonic and induced pluripotent stem cells (iPSCs. Further differentiation of the progenitors resulted in ramified microglia with highly motile processes, expressing typical microglial markers. Analyses of gene expression and cytokine release showed close similarities between iPSC-derived (iPSC-MG and human primary microglia as well as clear distinctions from macrophages. iPSC-MG were able to phagocytose and responded to ADP by producing intracellular Ca2+ transients, whereas macrophages lacked such response. The differentiation protocol was highly reproducible across several pluripotent stem cell lines.

  7. Proliferating resident microglia express the stem cell antigen CD34 in response to acute neural injury

    DEFF Research Database (Denmark)

    Ladeby, Rune; Wirenfeldt, Martin; Dalmau, Ishar

    2005-01-01

    -activated microglia in the facial motor nucleus following peripheral axotomy. The results suggest lesion-reactive microglia to consist of functionally distinct subpopulations of cells; a major population of activated resident CD34(+)Mac-1(+) microglia with a high capacity for self-renewal, and a subpopulation of CD34...

  8. Functional Studies of Missense TREM2 Mutations in Human Stem Cell-Derived Microglia

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    Philip W. Brownjohn

    2018-04-01

    Full Text Available Summary: The derivation of microglia from human stem cells provides systems for understanding microglial biology and enables functional studies of disease-causing mutations. We describe a robust method for the derivation of human microglia from stem cells, which are phenotypically and functionally comparable with primary microglia. We used stem cell-derived microglia to study the consequences of missense mutations in the microglial-expressed protein triggering receptor expressed on myeloid cells 2 (TREM2, which are causal for frontotemporal dementia-like syndrome and Nasu-Hakola disease. We find that mutant TREM2 accumulates in its immature form, does not undergo typical proteolysis, and is not trafficked to the plasma membrane. However, in the absence of plasma membrane TREM2, microglia differentiate normally, respond to stimulation with lipopolysaccharide, and are phagocytically competent. These data indicate that dementia-associated TREM2 mutations have subtle effects on microglia biology, consistent with the adult onset of disease in individuals with these mutations. : Brownjohn and colleagues report methods to generate microglia from induced pluripotent human stem cells, which they demonstrate are highly similar to cultured primary human microglia. Microglia differentiated from patient-derived stem cells carrying neurological disease-causing mutations in the TREM2 receptor differentiate normally and respond appropriately to pathogenic stimuli, despite the absence of functional TREM2 receptor on the plasma membrane. Keywords: dementia, microglia, TREM2, Nasu-Hakola disease, frontotemporal dementia, iPSC-microglia, neuroinflammation

  9. Characterizing newly repopulated microglia in the adult mouse: impacts on animal behavior, cell morphology, and neuroinflammation.

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    Monica R P Elmore

    Full Text Available Microglia are the primary immune cell in the brain and are postulated to play important roles outside of immunity. Administration of the dual colony-stimulating factor 1 receptor (CSF1R/c-Kit kinase inhibitor, PLX3397, to adult mice results in the elimination of ~99% of microglia, which remain eliminated for as long as treatment continues. Upon removal of the inhibitor, microglia rapidly repopulate the entire adult brain, stemming from a central nervous system (CNS resident progenitor cell. Using this method of microglial elimination and repopulation, the role of microglia in both healthy and diseased states can be explored. Here, we examine the responsiveness of newly repopulated microglia to an inflammatory stimulus, as well as determine the impact of these cells on behavior, cognition, and neuroinflammation. Two month-old wild-type mice were placed on either control or PLX3397 diet for 21 d to eliminate microglia. PLX3397 diet was then removed in a subset of animals to allow microglia to repopulate and behavioral testing conducted beginning at 14 d repopulation. Finally, inflammatory profiling of the microglia-repopulated brain in response to lipopolysaccharide (LPS; 0.25 mg/kg or phosphate buffered saline (PBS was determined 21 d after inhibitor removal using quantitative real time polymerase chain reaction (RT-PCR, as well as detailed analyses of microglial morphologies. We find mice with repopulated microglia to perform similarly to controls by measures of behavior, cognition, and motor function. Compared to control/resident microglia, repopulated microglia had larger cell bodies and less complex branching in their processes, which resolved over time after inhibitor removal. Inflammatory profiling revealed that the mRNA gene expression of repopulated microglia was similar to normal resident microglia and that these new cells appear functional and responsive to LPS. Overall, these data demonstrate that newly repopulated microglia function

  10. Microglia and Beyond: Innate Immune Cells As Regulators of Brain Development and Behavioral Function

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    Kathryn M. Lenz

    2018-04-01

    Full Text Available Innate immune cells play a well-documented role in the etiology and disease course of many brain-based conditions, including multiple sclerosis, Alzheimer’s disease, traumatic brain and spinal cord injury, and brain cancers. In contrast, it is only recently becoming clear that innate immune cells, primarily brain resident macrophages called microglia, are also key regulators of brain development. This review summarizes the current state of knowledge regarding microglia in brain development, with particular emphasis on how microglia during development are distinct from microglia later in life. We also summarize the effects of early life perturbations on microglia function in the developing brain, the role that biological sex plays in microglia function, and the potential role that microglia may play in developmental brain disorders. Finally, given how new the field of developmental neuroimmunology is, we highlight what has yet to be learned about how innate immune cells shape the development of brain and behavior.

  11. Microglia and Beyond: Innate Immune Cells As Regulators of Brain Development and Behavioral Function.

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    Lenz, Kathryn M; Nelson, Lars H

    2018-01-01

    Innate immune cells play a well-documented role in the etiology and disease course of many brain-based conditions, including multiple sclerosis, Alzheimer's disease, traumatic brain and spinal cord injury, and brain cancers. In contrast, it is only recently becoming clear that innate immune cells, primarily brain resident macrophages called microglia, are also key regulators of brain development. This review summarizes the current state of knowledge regarding microglia in brain development, with particular emphasis on how microglia during development are distinct from microglia later in life. We also summarize the effects of early life perturbations on microglia function in the developing brain, the role that biological sex plays in microglia function, and the potential role that microglia may play in developmental brain disorders. Finally, given how new the field of developmental neuroimmunology is, we highlight what has yet to be learned about how innate immune cells shape the development of brain and behavior.

  12. Primary microglia isolation from mixed glial cell cultures of neonatal rat brain tissue.

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    Tamashiro, Tami T; Dalgard, Clifton Lee; Byrnes, Kimberly R

    2012-08-15

    Microglia account for approximately 12% of the total cellular population in the mammalian brain. While neurons and astrocytes are considered the major cell types of the nervous system, microglia play a significant role in normal brain physiology by monitoring tissue for debris and pathogens and maintaining homeostasis in the parenchyma via phagocytic activity. Microglia are activated during a number of injury and disease conditions, including neurodegenerative disease, traumatic brain injury, and nervous system infection. Under these activating conditions, microglia increase their phagocytic activity, undergo morpohological and proliferative change, and actively secrete reactive oxygen and nitrogen species, pro-inflammatory chemokines and cytokines, often activating a paracrine or autocrine loop. As these microglial responses contribute to disease pathogenesis in neurological conditions, research focused on microglia is warranted. Due to the cellular heterogeneity of the brain, it is technically difficult to obtain sufficient microglial sample material with high purity during in vivo experiments. Current research on the neuroprotective and neurotoxic functions of microglia require a routine technical method to consistently generate pure and healthy microglia with sufficient yield for study. We present, in text and video, a protocol to isolate pure primary microglia from mixed glia cultures for a variety of downstream applications. Briefly, this technique utilizes dissociated brain tissue from neonatal rat pups to produce mixed glial cell cultures. After the mixed glial cultures reach confluency, primary microglia are mechanically isolated from the culture by a brief duration of shaking. The microglia are then plated at high purity for experimental study. The principle and protocol of this methodology have been described in the literature. Additionally, alternate methodologies to isolate primary microglia are well described. Homogenized brain tissue may be separated

  13. Bone marrow-derived cells in the population of spinal microglia after peripheral nerve injury

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    Tashima, Ryoichi; Mikuriya, Satsuki; Tomiyama, Daisuke; Shiratori-Hayashi, Miho; Yamashita, Tomohiro; Kohro, Yuta; Tozaki-Saitoh, Hidetoshi; Inoue, Kazuhide; Tsuda, Makoto

    2016-01-01

    Accumulating evidence indicates that peripheral nerve injury (PNI) activates spinal microglia that are necessary for neuropathic pain. Recent studies using bone marrow (BM) chimeric mice have reported that after PNI, circulating BM-derived cells infiltrate into the spinal cord and differentiate into microglia-like cells. This raises the possibility that the population of spinal microglia after PNI may be heterogeneous. However, the infiltration of BM cells in the spinal cord remains controversial because of experimental adverse effects of strong irradiation used for generating BM chimeric mice. In this study, we evaluated the PNI-induced spinal infiltration of BM-derived cells not only by irradiation-induced myeloablation with various conditioning regimens, but also by parabiosis and mice with genetically labelled microglia, models without irradiation and BM transplantation. Results obtained from these independent approaches provide compelling evidence indicating little contribution of circulating BM-derived cells to the population of spinal microglia after PNI. PMID:27005516

  14. Modulation of Hematopoietic Lineage Specification Impacts TREM2 Expression in Microglia-Like Cells Derived From Human Stem Cells.

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    Amos, Peter J; Fung, Susan; Case, Amanda; Kifelew, Jerusalem; Osnis, Leah; Smith, Carole L; Green, Kevin; Naydenov, Alipi; Aloi, Macarena; Hubbard, Jesse J; Ramakrishnan, Aravind; Garden, Gwenn A; Jayadev, Suman

    2017-01-01

    Microglia are the primary innate immune cell type in the brain, and their dysfunction has been linked to a variety of central nervous system disorders. Human microglia are extraordinarily difficult to obtain for experimental investigation, limiting our ability to study the impact of human genetic variants on microglia functions. Previous studies have reported that microglia-like cells can be derived from human monocytes or pluripotent stem cells. Here, we describe a reproducible relatively simple method for generating microglia-like cells by first deriving embryoid body mesoderm followed by exposure to microglia relevant cytokines. Our approach is based on recent studies demonstrating that microglia originate from primitive yolk sac mesoderm distinct from peripheral macrophages that arise during definitive hematopoiesis. We hypothesized that functional microglia could be derived from human stem cells by employing BMP-4 mesodermal specification followed by exposure to microglia-relevant cytokines, M-CSF, GM-CSF, IL-34, and TGF-β. Using immunofluorescence microscopy, flow cytometry, and reverse transcription polymerase chain reaction, we observed cells with microglia morphology expressing a repertoire of markers associated with microglia: Iba1, CX3CR1, CD11b, TREM2, HexB, and P2RY12. These microglia-like cells maintain myeloid functional phenotypes including Aβ peptide phagocytosis and induction of pro-inflammatory gene expression in response to lipopolysaccharide stimulation. Addition of small molecules BIO and SB431542, previously demonstrated to drive definitive hematopoiesis, resulted in decreased surface expression of TREM2. Together, these data suggest that mesodermal lineage specification followed by cytokine exposure produces microglia-like cells in vitro from human pluripotent stem cells and that this phenotype can be modulated by factors influencing hematopoietic lineage in vitro.

  15. Cellular and Molecular Characterization of Microglia : A Unique Immune Cell Population

    NARCIS (Netherlands)

    Sousa, Carole; Biber, Knut; Michelucci, Alessandro

    2017-01-01

    Microglia are essential for the development and function of the adult brain. Microglia arise from erythro-myeloid precursors in the yolk sac and populate the brain rudiment early during development. Unlike monocytes that are constantly renewed from bone marrow hematopoietic stem cells throughout

  16. Benfotiamine upregulates antioxidative system in activated BV-2 microglia cells

    OpenAIRE

    Bozic, Iva; Savic, Danijela; Stevanovic, Ivana; Pekovic, Sanja; Nedeljkovic, Nadezda; Lavrnja, Irena

    2015-01-01

    Chronic microglial activation and resulting sustained neuroinflammatory reaction are generally associated with neurodegeneration. Activated microglia acquires proinflammatory cellular profile that generates oxidative burst. Their persistent activation exacerbates inflammation, which damages healthy neurons via cytotoxic mediators, such as superoxide radical anion and nitric oxide. In our recent study, we have shown that benfotiamine (S-benzoylthiamine O-monophosphate) possesses anti-inflammat...

  17. Comparison of microglia and infiltrating CD11c+ cells as antigen presenting cells for T cell proliferation and cytokine response

    DEFF Research Database (Denmark)

    Wlodarczyk, Agnieszka; Løbner, Morten; Cédile, Oriane

    2014-01-01

    BACKGROUND: Tissue-resident antigen-presenting cells (APC) exert a major influence on the local immune environment. Microglia are resident myeloid cells in the central nervous system (CNS), deriving from early post-embryonic precursors, distinct from adult hematopoietic lineages. Dendritic cells...... (DC) and macrophages infiltrate the CNS during experimental autoimmune encephalomyelitis (EAE). Microglia are not considered to be as effective APC as DC or macrophages. METHODS: In this work we compared the antigen presenting capacity of CD11c+ and CD11c- microglia subsets with infiltrating CD11c......+ APC, which include DC. The microglial subpopulations (CD11c- CD45dim CD11b+ and CD11c+ CD45dim CD11b+) as well as infiltrating CD11c+ CD45high cells were sorted from CNS of C57BL/6 mice with EAE. Sorted cells were characterised by flow cytometry for surface phenotype and by quantitative real-time PCR...

  18. Anti-inflammatory effects of tanshinone IIA on radiation-induced microglia BV-2 cells inflammatory response

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    Dong, Xiaorong; Dong, Jihua; Zhang, Ruiguang

    2009-01-01

    AIM: The aim of this study was to explore the inhibitory effects of Tanshinone II(A) on the production of proinflammation cytokines in radiation-stimulated microglia. METHODS: Microglia cells were treated with 2, 4, 8, 16, and 32 Gy of irradiation or sham-irradiated in the presence or absence of ...

  19. RAE-1 expression is induced during experimental autoimmune encephalomyelitis and is correlated with microglia cell proliferation.

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    Djelloul, Mehdi; Popa, Natalia; Pelletier, Florence; Raguénez, Gilda; Boucraut, José

    2016-11-01

    Retinoic acid early induced transcript-1 (RAE-1) glycoproteins are ligands of the activating immune receptor NKG2D. They are known as stress molecules induced in pathological conditions. We previously reported that progenitor cells express RAE-1 in physiological conditions and we described a correlation between RAE-1 expression and cell proliferation. In addition, we showed that Raet1 transcripts are induced in the spinal cord of experimental autoimmune encephalomyelitis (EAE) mice. EAE is a model for multiple sclerosis which is accompanied by microglia proliferation and activation, recruitment of immune cells and neurogenesis. We herein studied the time course expression of the two members of the Raet1 gene family present in C57BL/6 mice, namely Raet1d and Raet1e, in the spinal cord during EAE. We report that Raet1d and Raet1e genes are induced early upon EAE onset and reach a maximal expression at the peak of the pathology. We show that myeloid cells, i.e. macrophages as well as microglia, are cellular sources of Raet1 transcripts. We also demonstrate that only Raet1d expression is induced in microglia, whereas macrophages expressed both Raet1d and Raet1e. Furthermore, we investigated the dynamics of RAE-1 expression in microglia cultures. RAE-1 induction correlated with cell proliferation but not with M1/M2 phenotypic orientation. We finally demonstrate that macrophage colony-stimulating factor (M-CSF) is a major factor controlling RAE-1 expression in microglia. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. A Role of Fluoride on Free Radical Generation and Oxidative Stress in BV-2 Microglia Cells

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    Xi Shuhua

    2012-01-01

    Full Text Available The generation of ROS and lipid peroxidation has been considered to play an important role in the pathogenesis of chronic fluoride toxicity. In the present study, we observed that fluoride activated BV-2 microglia cell line by observing OX-42 expression in immunocytochemistry. Intracellular superoxide dismutase (SOD, glutathione (GSH, malondialdehyde (MDA, reactive oxygen species (ROS, superoxide anions (O2∙-, nitric oxide synthase (NOS, nitrotyrosine (NT and nitric oxide (NO, NOS in cell medium were determined for oxidative stress assessment. Our study found that NaF of concentration from 5 to 20 mg/L can stimuli BV-2 cells to change into activated microglia displaying upregulated OX-42 expression. SOD activities significantly decreased in fluoride-treated BV-2 cells as compared with control, and MDA concentrations and contents of ROS and O2∙- increased in NaF-treated cells. Activities of NOS in cells and medium significantly increased with fluoride concentrations in a dose-dependent manner. NT concentrations also increased significantly in 10 and 50 mg/L NaF-treated cells compared with the control cells. Our present study demonstrated that toxic effects of fluoride on the central nervous system possibly partly ascribed to activiting of microglia, which enhanced oxidative stress induced by ROS and reactive nitrogen species.

  1. Isolation of murine postnatal brain microglia for phenotypic characterization using magnetic cell separation technology.

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    Harms, Ashley S; Tansey, Malú G

    2013-01-01

    To shorten the time between brain harvesting and microglia isolation, and characterization, we utilized the MACS(®) neural dissociation kit followed by OctoMACS(®) CD11b magnetic bead isolation technique to positively select for brain microglia expressing the pan-microglial marker CD11b, a key subunit of the membrane attack complex (MAC). This protocol yields a viable and highly pure (>95%) microglial population of approximately 500,000 cells per pup that is amenable for in vitro characterization within hours or days after being harvested from brain tissue. Primary microglia from C57Bl/6 mice were plated for next-day analyses of morphology and cellular markers by immunocytochemistry or for analysis of gene expression under resting or LPS-stimulated conditions. The ease of isolation enables investigators to perform molecular and cellular analyses without having to wait 1-2 weeks to isolate microglia by conventional methods involving mechanical agitation to dislodge these from astrocyte beds.

  2. Cell cycle-dependent regulation of kainate-induced inward currents in microglia

    International Nuclear Information System (INIS)

    Yamada, Jun; Sawada, Makoto; Nakanishi, Hiroshi

    2006-01-01

    Microglia are reported to have α-amino-hydroxy-5-methyl-isoxazole-4-propionate/kainate (KA) types. However, only small population of primary cultured rat microglia (approximately 20%) responded to KA. In the present study, we have attempted to elucidate the regulatory mechanism of responsiveness to KA in GMIR1 rat microglial cell line. When the GMIR1 cells were plated at a low density in the presence of granulocyte macrophage colony-stimulating factor, the proliferation rate increased and reached the peak after 2 days in culture and then gradually decreased because of density-dependent inhibition. At cell proliferation stage, approximately 80% of the GMIR1 cells exhibited glutamate (Glu)- and KA-induced inward currents at cell proliferation stage, whereas only 22.5% of the cells showed responsiveness to Glu and KA at cell quiescent stage. Furthermore, the mean amplitudes of inward currents induced by Glu and KA at cell proliferation stage (13.8 ± 3.0 and 8.4 ± 0.6 pA) were significantly larger than those obtained at cell quiescent stage (4.7 ± 0.8 and 6.2 ± 1.2 pA). In the GMIR1 cells, KA-induced inward currents were markedly inhibited by (RS)-3-(2-carboxybenzyl) willardiine (UBP296), a selective antagonist for KA receptors. The KA-responsive cells also responded to (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a selective agonist for GluR5, in both GMIR1 cells and primary cultured rat microglia. Furthermore, mRNA levels of the KA receptor subunits, GluR5 and GluR6, at the cell proliferation stage were significantly higher than those at the cell quiescent stage. Furthermore, the immunoreactivity for GluR6/7 was found to increase in activated microglia in the post-ischemic hippocampus. These results strongly suggest that microglia have functional KA receptors mainly consisting of GluR5 and GluR6, and the expression levels of these subunits are closely regulated by the cell cycle mechanism

  3. JNK and NADPH Oxidase Involved in Fluoride-Induced Oxidative Stress in BV-2 Microglia Cells

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    Ling Yan

    2013-01-01

    Full Text Available Excessive fluoride may cause central nervous system (CNS dysfunction, and oxidative stress is a recognized mode of action of fluoride toxicity. In CNS, activated microglial cells can release more reactive oxygen species (ROS, and NADPH oxidase (NOX is the major enzyme for the production of extracellular superoxide in microglia. ROS have been characterized as an important secondary messenger and modulator for various mammalian intracellular signaling pathways, including the MAPK pathways. In this study we examined ROS production and TNF-α, IL-1β inflammatory cytokines releasing, and the expression of MAPKs in BV-2 microglia cells treated with fluoride. We found that fluoride increased JNK phosphorylation level of BV-2 cells and pretreatment with JNK inhibitor SP600125 markedly reduced the levels of intracellular and NO. NOX inhibitor apocynin and iNOS inhibitor SMT dramatically decreased NaF-induced ROS and NO generations, respectively. Antioxidant melatonin (MEL resulted in a reduction in JNK phosphorylation in fluoride-stimulated BV-2 microglia. The results confirmed that NOX and iNOS played an important role in fluoride inducing oxidative stress and NO production and JNK took part in the oxidative stress induced by fluoride and meanwhile also could be activated by ROS in fluoride-treated BV-2 cells.

  4. JNK and NADPH Oxidase Involved in Fluoride-Induced Oxidative Stress in BV-2 Microglia Cells

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    Yan, Ling; Liu, Shengnan; Wang, Chen; Wang, Fei; Song, Yingli; Yan, Nan; Xi, Shuhua; Liu, Ziyou; Sun, Guifan

    2013-01-01

    Excessive fluoride may cause central nervous system (CNS) dysfunction, and oxidative stress is a recognized mode of action of fluoride toxicity. In CNS, activated microglial cells can release more reactive oxygen species (ROS), and NADPH oxidase (NOX) is the major enzyme for the production of extracellular superoxide in microglia. ROS have been characterized as an important secondary messenger and modulator for various mammalian intracellular signaling pathways, including the MAPK pathways. In this study we examined ROS production and TNF-α, IL-1β inflammatory cytokines releasing, and the expression of MAPKs in BV-2 microglia cells treated with fluoride. We found that fluoride increased JNK phosphorylation level of BV-2 cells and pretreatment with JNK inhibitor SP600125 markedly reduced the levels of intracellular O2 ·− and NO. NOX inhibitor apocynin and iNOS inhibitor SMT dramatically decreased NaF-induced ROS and NO generations, respectively. Antioxidant melatonin (MEL) resulted in a reduction in JNK phosphorylation in fluoride-stimulated BV-2 microglia. The results confirmed that NOX and iNOS played an important role in fluoride inducing oxidative stress and NO production and JNK took part in the oxidative stress induced by fluoride and meanwhile also could be activated by ROS in fluoride-treated BV-2 cells. PMID:24072958

  5. Microglia immunophenotyping in gliomas

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    Annovazzi, Laura; Mellai, Marta; Bovio, Enrica; Mazzetti, Samanta; Pollo, Bianca; Schiffer, Davide

    2018-01-01

    Microglia, once assimilated to peripheral macrophages, in gliomas has long been discussed and currently it is hypothesized to play a pro-tumor role in tumor progression. Uncertain between M1 and M2 polarization, it exchanges signals with glioma cells to create an immunosuppressive microenvironment and stimulates cell proliferation and migration. Four antibodies are currently used for microglia/macrophage identification in tissues that exhibit different cell forms and cell localization. The aim of the present work was to describe the distribution of the different cell forms and to deduce their significance on the basis of what is known on their function from the literature. Normal resting microglia, reactive microglia, intermediate and bumpy forms and macrophage-like cells can be distinguished by Iba1, CD68, CD16 and CD163 and further categorized by CD11b, CD45, c-MAF and CD98. The number of microglia/macrophages strongly increased from normal cortex and white matter to infiltrating and solid tumors. The ramified microglia accumulated in infiltration areas of both high- and low-grade gliomas, when hypertrophy and hyperplasia occur. In solid tumors, intermediate and bumpy forms prevailed and there is a large increase of macrophage-like cells in glioblastoma. The total number of microglia cells did not vary among the three grades of malignancy, but macrophage-like cells definitely prevailed in high-grade gliomas and frequently expressed CD45 and c-MAF. CD98+ cells were present. Microglia favors tumor progression, but many aspects suggest that the phagocytosing function is maintained. CD98+ cells can be the product of fusion, but also of phagocytosis. Microglia correlated with poorer survival in glioblastoma, when considering CD163+ cells, whereas it did not change prognosis in isocitrate dehydrogenase-mutant low grade gliomas. PMID:29399160

  6. Distinct spatial distribution of microglia and macrophages following mesenchymal stem cell implantation in mouse brain.

    Science.gov (United States)

    Le Blon, Debbie; Hoornaert, Chloé; Daans, Jasmijn; Santermans, Eva; Hens, Niel; Goossens, Herman; Berneman, Zwi; Ponsaerts, Peter

    2014-09-01

    Although implantation of cellular material in the central nervous system (CNS) is a key direction in CNS regenerative medicine, this approach is currently limited by the occurrence of strong endogenous immune cell responses. In a model of mesenchymal stem cell (MSC) grafting in the CNS of immune-competent mice, we previously described that MSC grafts become highly surrounded and invaded by Iba1(+) myeloid cells (microglia and/or macrophages). Here, following grafting of blue fluorescent protein (BFP)-expressing MSC in the CNS of CX3CR1(+/-) and CX3CR1(-/-) mice, our results indicate: (1) that the observed inflammatory response is independent of the fractalkine signalling axis, and (2) that a significant spatial distribution of Iba1(+) inflammatory cells occurs, in which Iba1(+) CX3CR1(+) myeloid cells mainly surround the MSC graft and Iba1(+) CX3CR1(-) myeloid cells mainly invade the graft at 10 days post transplantation. Although Iba1(+) CX3CR1(+) myeloid cells are considered to be of resident microglial origin, Iba1(+) CX3CR1(-) myeloid cells are most likely of peripheral monocyte/macrophage origin. In order to confirm the latter, we performed MSC-BFP grafting experiments in the CNS of eGFP(+) bone marrow chimeric C57BL/6 mice. Analysis of MSC-BFP grafts in the CNS of these mice confirmed our observation that peripheral monocytes/macrophages invade the MSC graft and that resident microglia surround the MSC graft site. Furthermore, analysis of major histocompatibility complex class II (MHCII) expression revealed that mainly macrophages, but not microglia, express this M1 pro-inflammatory marker in the context of MSC grafting in the CNS. These results again highlight the complexity of cell implantation immunology in the CNS.

  7. Plasma Membrane Protein Profiling in Beta-Amyloid-Treated Microglia Cell Line.

    Science.gov (United States)

    Correani, Virginia; Di Francesco, Laura; Mignogna, Giuseppina; Fabrizi, Cinzia; Leone, Stefano; Giorgi, Alessandra; Passeri, Alessia; Casata, Roberto; Fumagalli, Lorenzo; Maras, Bruno; Schininà, M Eugenia

    2017-09-01

    In the responsiveness of microglia to toxic stimuli, plasma membrane proteins play a key role. In this study we treated with a synthetic beta amyloid peptide murine microglial cells metabolically differently labelled with stable isotope amino acids (SILAC). The plasma membrane was selectively enriched by a multi-stage aqueous two-phase partition system. We were able to identify by 1D-LC-MS/MS analyses 1577 proteins, most of them are plasma membrane proteins according to the Gene Ontology annotation. An unchanged level of amyloid receptors in this data set suggests that microglia preserve their responsiveness capability to the environment even after 24-h challenge with amyloid peptides. On the other hand, 14 proteins were observed to change their plasma membrane abundance to a statistically significant extent. Among these, we proposed as reliable biomarkers of the inflammatory microglia phenotype in AD damaged tissues MAP/microtubule affinity-regulating kinase 3 (MARK3), Interferon-induced transmembrane protein 3 (IFITM3), Annexins A5 and A7 (ANXA5, ANXA7) and Neuropilin-1 (NRP1), all proteins known to be involved in the inflammation processes and in microtubule network assembly rate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Fluoxetine Prevents Oligodendrocyte Cell Death by Inhibiting Microglia Activation after Spinal Cord Injury

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    Lee, Jee Y.; Kang, So R.

    2015-01-01

    Abstract Oligodendrocyte cell death and axon demyelination after spinal cord injury (SCI) are known to be important secondary injuries contributing to permanent neurological disability. Thus, blocking oligodendrocyte cell death should be considered for therapeutic intervention after SCI. Here, we demonstrated that fluoxetine, an antidepressant drug, alleviates oligodendrocyte cell death by inhibiting microglia activation after SCI. After injury at the T9 level with a Precision Systems and Instrumentation (Lexington, KY) device, fluoxetine (10 mg/kg, intraperitoneal) was administered once a day for the indicated time points. Immunostaining with CD11b (OX-42) antibody and quantification analysis showed that microglia activation was significantly inhibited by fluoxetine at 5 days after injury. Fluoxetine also significantly inhibited activation of p38 mitogen-activated protein kinase (p38-MAPK) and expression of pro-nerve growth factor (pro-NGF), which is known to mediate oligodendrocyte cell death through the p75 neurotrophin receptor after SCI. In addition, fluoxetine attenuated activation of Ras homolog gene family member A and decreased the level of phosphorylated c-Jun and, ultimately, alleviated caspase-3 activation and significantly reduced cell death of oligodendrocytes at 5 days after SCI. Further, the decrease of myelin basic protein, myelin loss, and axon loss in white matter was also significantly blocked by fluoxetine, as compared to vehicle control. These results suggest that fluoxetine inhibits oligodendrocyte cell death by inhibiting microglia activation and p38-MAPK activation, followed by pro-NGF production after SCI, and provide a potential usage of fluoxetine for a therapeutic agent after acute SCI in humans. PMID:25366938

  9. Leptomeningeal Cells Transduce Peripheral Macrophages Inflammatory Signal to Microglia in Reponse to Porphyromonas gingivalis LPS

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    Yicong Liu

    2013-01-01

    Full Text Available We report here that the leptomeningeal cells transduce inflammatory signals from peripheral macrophages to brain-resident microglia in response to Porphyromonas gingivalis (P.g. LPS. The expression of Toll-like receptor 2 (TLR2, TLR4, TNF-α, and inducible NO synthase was mainly detected in the gingival macrophages of chronic periodontitis patients. In in vitro studies, P.g. LPS induced the secretion of TNF-α and IL-1β from THP-1 human monocyte-like cell line and RAW264.7 mouse macrophages. Surprisingly, the mean mRNA levels of TNF-α and IL-1β in leptomeningeal cells after treatment with the conditioned medium from P.g. LPS-stimulated RAW264.7 macrophages were significantly higher than those after treatment with P.g. LPS alone. Furthermore, the mean mRNA levels of TNF-α and IL-1β in microglia after treatment with the conditioned medium from P.g. LPS-stimulated leptomeningeal cells were significantly higher than those after P.g. LPS alone. These observations suggest that leptomeninges serve as an important route for transducing inflammatory signals from macrophages to microglia by secretion of proinflammatory mediators during chronic periodontitis. Moreover, propolis significantly reduced the P.g. LPS-induced TNF-α and IL-1 β production by leptomeningeal cells through inhibiting the nuclear factor-κB signaling pathway. Together with the inhibitory effect on microglial activation, propolis may be beneficial in preventing neuroinflammation during chronic periodontitis.

  10. Microglia Induce Neurotoxic IL-17+ γδ T Cells Dependent on TLR2, TLR4, and TLR9 Activation.

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    Katja Derkow

    Full Text Available Interleukin-17 (IL-17 acts as a key regulator in central nervous system (CNS inflammation. γδ T cells are an important innate source of IL-17. Both IL-17+ γδ T cells and microglia, the major resident immune cells of the brain, are involved in various CNS disorders such as multiple sclerosis and stroke. Also, activation of Toll-like receptor (TLR signaling pathways contributes to CNS damage. However, the mechanisms underlying the regulation and interaction of these cellular and molecular components remain unclear.In this study, we investigated the crosstalk between γδ T cells and microglia activated by TLRs in the context of neuronal damage. To this end, co-cultures of IL-17+ γδ T cells, neurons, and microglia were analyzed by immunocytochemistry, flow cytometry, ELISA and multiplex immunoassays.We report here that IL-17+ γδ T cells but not naïve γδ T cells induce a dose- and time-dependent decrease of neuronal viability in vitro. While direct stimulation of γδ T cells with various TLR ligands did not result in up-regulation of CD69, CD25, or in IL-17 secretion, supernatants of microglia stimulated by ligands specific for TLR2, TLR4, TLR7, or TLR9 induced activation of γδ T cells through IL-1β and IL-23, as indicated by up-regulation of CD69 and CD25 and by secretion of vast amounts of IL-17. This effect was dependent on the TLR adaptor myeloid differentiation primary response gene 88 (MyD88 expressed by both γδ T cells and microglia, but did not require the expression of TLRs by γδ T cells. Similarly to cytokine-primed IL-17+ γδ T cells, IL-17+ γδ T cells induced by supernatants derived from TLR-activated microglia also caused neurotoxicity in vitro. While these neurotoxic effects required stimulation of TLR2, TLR4, or TLR9 in microglia, neuronal injury mediated by bone marrow-derived macrophages did not require TLR signaling. Neurotoxicity mediated by IL-17+ γδ T cells required a direct cell-cell contact between T

  11. Simvastatin affects cell motility and actin cytoskeleton distribution of microglia

    NARCIS (Netherlands)

    Kuipers, HF; Rappert, Angelika A.C.; Mommaas, AM; Van Haastert, ES; Van der Valk, P; Boddeke, HWGM; Biber, KPH; Van den Elsen, PJ

    2006-01-01

    Statin treatment is proposed to be a new potential therapy for multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system. The effects of statin treatment on brain cells, however, are hardly understood. We therefore evaluated the effects of simvastatin treatment on

  12. What is microglia neurotoxicity (Not)?

    DEFF Research Database (Denmark)

    Biber, Knut; Owens, Trevor; Boddeke, Erik

    2014-01-01

    and vulnerable organ like the brain should host numerous potential killers, we here review the concept of microglia neurotoxicity. On one hand it is discussed that most of our understanding about how microglia kill neurons is based on in vitro experiments or correlative staining studies that suffer from...... the difficulty to discriminate microglia and peripheral myeloid cells in the diseased brain. On the other hand it is described that a more functional approach by mutating, inactivating or deleting microglia is seldom associated with a beneficial outcome in an acute injury situation, suggesting that microglia...

  13. Microglia antioxidant systems and redox signaling

    DEFF Research Database (Denmark)

    Vilhardt, F; Haslund-Vinding, J; Jaquet, V

    2017-01-01

    For many years microglia, the resident CNS macrophages, have been considered only in the context of pathology, but microglia are also glia cells with important physiological functions. Microglia-derived oxidant production by NADPH oxidase (NOX2) is implicated in many CNS disorders. Oxidants don...

  14. Association of Glioblastoma Multiforme Stem Cell Characteristics, Differentiation, and Microglia Marker Genes with Patient Survival

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    Sandra Bien-Möller

    2018-01-01

    Full Text Available Patients with glioblastoma multiforme (GBM are at high risk to develop a relapse despite multimodal therapy. Assumedly, glioma stem cells (GSCs are responsible for treatment resistance of GBM. Identification of specific GSC markers may help to develop targeted therapies. Here, we performed expression analyses of stem cell (ABCG2, CD44, CD95, CD133, ELF4, Nanog, and Nestin as well as differentiation and microglia markers (GFAP, Iba1, and Sparc in GBM compared to nonmalignant brain. Furthermore, the role of these proteins for patient survival and their expression in LN18 stem-like neurospheres was analyzed. At mRNA level, ABCG2 and CD95 were reduced, GFAP was unchanged; all other investigated markers were increased in GBM. At protein level, CD44, ELF4, Nanog, Nestin, and Sparc were elevated in GBM, but only CD133 and Nestin were strongly associated with survival time. In addition, ABCG2 and GFAP expression was decreased in LN18 neurospheres whereas CD44, CD95, CD133, ELF4, Nanog, Nestin, and Sparc were upregulated. Altogether only CD133 and Nestin were associated with survival rates. This raises concerns regarding the suitability of the other target structures as prognostic markers, but makes both CD133 and Nestin candidates for GBM therapy. Nevertheless, a search for more specific marker proteins is urgently needed.

  15. ROLE OF MELATONIN IN EXPRESSION OF MALONDIALDEHYDE ON MICROGLIA CELLS OF RAT INDUCED HEAD INJURY

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    K. I. Nasution

    2015-08-01

    Full Text Available Background: brain injury is condition that harm human life. This study examines the application of melatonin in reducing oxidant status and barriers to the formation of cerebral edema in a rat brain injury model. The main purpose of this study is to prove the role of melatonin on the expression of Malondialdehyde (MDA and histological injury in a rat head injury model. Methods: This study was a randomized experimental posttest only control group design. This experimental was carried out on male Sprague Dawley strain Rattus novergicus, aged of 10-12 weeks, and weight of 300 g. Rat brain injury model was performed based on Marmarou (1994.1 Histology were observed using hematoxilen-eosin staining and immunohistochemistry, MDA was assessed using antibodies specific to each MDA protein. Observation and calculation of immunohistochemistry studies were also performed. Results: In this study, histological observation area covers an area of bleeding, number of immune-competent cells and the diameter of the arteries. Histology observation results showed that there is a significant reduction in diameter of arterial blood vessels of the brain injury tissue. Immunohisto-chemistry results showed that there is a significant reduction of MDA expression amount microglia cells of brain injury tissue. Conclusion: From this study, it can be concluded that Melatonin is a potent hydrogen peroxide scavenger that reduce the production of MDA. 

  16. Association of Glioblastoma Multiforme Stem Cell Characteristics, Differentiation, and Microglia Marker Genes with Patient Survival

    Science.gov (United States)

    Balz, Ellen; Herzog, Susann; Plantera, Laura; Vogelgesang, Silke; Seifert, Carolin; Bialke, Angela; Venugopal, Chitra; Singh, Sheila K.; Hoffmann, Wolfgang; Schroeder, Henry W. S.

    2018-01-01

    Patients with glioblastoma multiforme (GBM) are at high risk to develop a relapse despite multimodal therapy. Assumedly, glioma stem cells (GSCs) are responsible for treatment resistance of GBM. Identification of specific GSC markers may help to develop targeted therapies. Here, we performed expression analyses of stem cell (ABCG2, CD44, CD95, CD133, ELF4, Nanog, and Nestin) as well as differentiation and microglia markers (GFAP, Iba1, and Sparc) in GBM compared to nonmalignant brain. Furthermore, the role of these proteins for patient survival and their expression in LN18 stem-like neurospheres was analyzed. At mRNA level, ABCG2 and CD95 were reduced, GFAP was unchanged; all other investigated markers were increased in GBM. At protein level, CD44, ELF4, Nanog, Nestin, and Sparc were elevated in GBM, but only CD133 and Nestin were strongly associated with survival time. In addition, ABCG2 and GFAP expression was decreased in LN18 neurospheres whereas CD44, CD95, CD133, ELF4, Nanog, Nestin, and Sparc were upregulated. Altogether only CD133 and Nestin were associated with survival rates. This raises concerns regarding the suitability of the other target structures as prognostic markers, but makes both CD133 and Nestin candidates for GBM therapy. Nevertheless, a search for more specific marker proteins is urgently needed. PMID:29535786

  17. Regionally distinct responses of microglia and glial progenitor cells to whole brain irradiation in adult and aging rats.

    Science.gov (United States)

    Hua, Kun; Schindler, Matthew K; McQuail, Joseph A; Forbes, M Elizabeth; Riddle, David R

    2012-01-01

    Radiation therapy has proven efficacy for treating brain tumors and metastases. Higher doses and larger treatment fields increase the probability of eliminating neoplasms and preventing reoccurrence, but dose and field are limited by damage to normal tissues. Normal tissue injury is greatest during development and in populations of proliferating cells but also occurs in adults and older individuals and in non-proliferative cell populations. To better understand radiation-induced normal tissue injury and how it may be affected by aging, we exposed young adult, middle-aged, and old rats to 10 Gy of whole brain irradiation and assessed in gray- and white matter the responses of microglia, the primary cellular mediators of radiation-induced neuroinflammation, and oligodendrocyte precursor cells, the largest population of proliferating cells in the adult brain. We found that aging and/or irradiation caused only a few microglia to transition to the classically "activated" phenotype, e.g., enlarged cell body, few processes, and markers of phagocytosis, that is seen following more damaging neural insults. Microglial changes in response to aging and irradiation were relatively modest and three markers of reactivity - morphology, proliferation, and expression of the lysosomal marker CD68- were regulated largely independently within individual cells. Proliferation of oligodendrocyte precursors did not appear to be altered during normal aging but increased following irradiation. The impacts of irradiation and aging on both microglia and oligodendrocyte precursors were heterogeneous between white- and gray matter and among regions of gray matter, indicating that there are regional regulators of the neural response to brain irradiation. By several measures, the CA3 region of the hippocampus appeared to be differentially sensitive to effects of aging and irradiation. The changes assessed here likely contribute to injury following inflammatory challenges like brain irradiation and

  18. Regionally distinct responses of microglia and glial progenitor cells to whole brain irradiation in adult and aging rats.

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    Kun Hua

    Full Text Available Radiation therapy has proven efficacy for treating brain tumors and metastases. Higher doses and larger treatment fields increase the probability of eliminating neoplasms and preventing reoccurrence, but dose and field are limited by damage to normal tissues. Normal tissue injury is greatest during development and in populations of proliferating cells but also occurs in adults and older individuals and in non-proliferative cell populations. To better understand radiation-induced normal tissue injury and how it may be affected by aging, we exposed young adult, middle-aged, and old rats to 10 Gy of whole brain irradiation and assessed in gray- and white matter the responses of microglia, the primary cellular mediators of radiation-induced neuroinflammation, and oligodendrocyte precursor cells, the largest population of proliferating cells in the adult brain. We found that aging and/or irradiation caused only a few microglia to transition to the classically "activated" phenotype, e.g., enlarged cell body, few processes, and markers of phagocytosis, that is seen following more damaging neural insults. Microglial changes in response to aging and irradiation were relatively modest and three markers of reactivity - morphology, proliferation, and expression of the lysosomal marker CD68- were regulated largely independently within individual cells. Proliferation of oligodendrocyte precursors did not appear to be altered during normal aging but increased following irradiation. The impacts of irradiation and aging on both microglia and oligodendrocyte precursors were heterogeneous between white- and gray matter and among regions of gray matter, indicating that there are regional regulators of the neural response to brain irradiation. By several measures, the CA3 region of the hippocampus appeared to be differentially sensitive to effects of aging and irradiation. The changes assessed here likely contribute to injury following inflammatory challenges like

  19. Microglia in the mouse retina alter the structure and function of retinal pigmented epithelial cells: a potential cellular interaction relevant to AMD.

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    Wenxin Ma

    2009-11-01

    Full Text Available Age-related macular degeneration (AMD is a leading cause of legal blindness in the elderly in the industrialized word. While the immune system in the retina is likely to be important in AMD pathogenesis, the cell biology underlying the disease is incompletely understood. Clinical and basic science studies have implicated alterations in the retinal pigment epithelium (RPE layer as a locus of early change. Also, retinal microglia, the resident immune cells of the retina, have been observed to translocate from their normal position in the inner retina to accumulate in the subretinal space close to the RPE layer in AMD eyes and in animal models of AMD.In this study, we examined the effects of retinal microglia on RPE cells using 1 an in vitro model where activated retinal microglia are co-cultured with primary RPE cells, and 2 an in vivo mouse model where retinal microglia are transplanted into the subretinal space. We found that retinal microglia induced in RPE cells 1 changes in RPE structure and distribution, 2 increased expression and secretion of pro-inflammatory, chemotactic, and pro-angiogenic molecules, and 3 increased extent of in vivo choroidal neovascularization in the subretinal space.These findings share similarities with important pathological features found in AMD and suggest the relevance of microglia-RPE interactions in AMD pathogenesis. We speculate that the migration of retinal microglia into the subretinal space in early stages of the disease induces significant changes in RPE cells that perpetuate further microglial accumulation, increase inflammation in the outer retina, and fosters an environment conducive for the formation of neovascular changes responsible for much of vision loss in advanced AMD.

  20. Introducing directly induced microglia-like (iMG cells from fresh human monocytes: A novel translational research tool for psychiatric disorders.

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    Masahiro eOhgidani

    2015-05-01

    Full Text Available Microglia, glial cells with immunological functions, have been implicated in various neurological diseases and psychiatric disorders in rodent studies, and human postmortem and PET studies. However, the deeper molecular implications of living human microglia have not been clarified.Here, we introduce a novel translational research approach focusing on human microglia. We have recently developed a new technique for creating induced microglia-like (iMG cells from human peripheral blood. Two cytokines, GM-CSF and IL-34, converted human monocytes into the iMG cells within 14 days, which show various microglial characterizations; expressing markers, forming a ramified morphology, and phagocytic activity with various cytokine releases. We have already confirmed the applicability of this technique by analyzing iMG cells from a patient of Nasu-Hakola disease (Ohgidani et al., Sci Rep 2014. We herein show possible applications of the iMG cells in translational research.We believe that this iMG technique will open the door to explore various unknown dynamic aspects of human microglia in psychiatric disorders. This also opens new routes for psychopharmacological approach such as drug efficacy screening and personalized medicine.

  1. A dual role for microglia in promoting tissue inhibitor of metalloproteinase (TIMP expression in glial cells in response to neuroinflammatory stimuli

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    Milner Richard

    2011-06-01

    Full Text Available Abstract Background By neutralizing the effect of the matrix metalloproteinases (MMPs, the tissue inhibitors of matrix metalloproteinases (TIMPs play a critical role in maintaining tissue proteolysis in balance. As the major reactive glial cell types in the central nervous system (CNS, microglia and astrocytes play fundamental roles in mediating tissue breakdown and repair. As such, it is important to define the TIMP expression profile in these cells, as well as the mechanisms of regulation by neuroinflammatory stimuli. Methods Primary mixed glial cultures (MGC, pure microglia, and pure astrocytes were used in this study. To study astrocytes, we employed a recently described pure astrocyte culture system, which has the major advantage of totally lacking microglia. The three different types of culture were treated with lipopolysaccharide (LPS or individual cytokines, and cell culture supernatants assayed for TIMP-1 or TIMP-2 protein expression by western blot. Results LPS induced TIMP-1 expression in MGC, but not in pure astrocyte or microglial cultures. When pure astrocytes were treated with the cytokines IL-1β, IFN-γ, TNF or TGF-β1, only IL-1β induced TIMP-1 expression. Significantly, astrocyte TIMP-1 expression was restored in LPS-treated astrocyte cultures after the addition of microglia, or conditioned medium taken from LPS-activated microglia (MG-CM. Furthermore, this effect was lost after depletion of IL-1β from MG-CM. By contrast, TIMP-2 was constitutively expressed by astrocytes, whereas microglia expressed TIMP-2 only after exposure to serum. Conclusions Taken together, these results demonstrate an important concept in glial interactions, by showing that microglia play a central role in regulating glial cell expression of TIMPs, and identify microglial IL-1β as playing a key role in mediating microglial-astrocyte communication.

  2. Neuroprotective effects of glyceryl nonivamide against microglia-like cells and 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y human dopaminergic neuroblastoma cells.

    Science.gov (United States)

    Lin, Yi-Chin; Uang, Hao-Wei; Lin, Rong-Jyh; Chen, Ing-Jun; Lo, Yi-Ching

    2007-12-01

    Glyceryl nonivamide (GLNVA), a vanilloid receptor (VR) agonist, has been reported to have calcitonin gene-related peptide-associated vasodilatation and to prevent subarachnoid hemorrhage-induced cerebral vasospasm. In this study, we investigated the neuroprotective effects of GLNVA on activated microglia-like cell mediated- and proparkinsonian neurotoxin 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in human dopaminergic neuroblastoma SH-SY5Y cells. In coculture conditions, we used lipopolysaccharide (LPS)-stimulated BV-2 cells as a model of activated microglia. LPS-induced neuronal death was significantly inhibited by diphenylene iodonium (DPI), an inhibitor of NADPH oxidase. However, capsazepine, the selective VR1 antagonist, did not block the neuroprotective effects of GLNVA. GLNVA reduced LPS-activated microglia-mediated neuronal death, but it lacked protection in DPI-pretreated cultures. GLNVA also decreased LPS activated microglia induced overexpression of neuronal nitric-oxide synthase (nNOS) and glycoprotein 91 phagocyte oxidase (gp91(phox)) on SH-SY5Y cells. Pretreatment of BV-2 cells with GLNVA diminished LPS-induced nitric oxide production, overexpression of inducible nitric-oxide synthase (iNOS), and gp91(phox) and intracellular reactive oxygen species (iROS). GLNVA also reduced cyclooxygenase (COX)-2 expression, inhibitor of nuclear factor (NF)-kappaB (IkappaB)alpha/IkappaBbeta degradation, NF-kappaB activation, and the overproduction of tumor necrosis factor-alpha, interleukin (IL)-1beta, and prostaglandin E2 in BV-2 cells. However, GLNVA augmented anti-inflammatory cytokine IL-10 production on LPS-stimulated BV-2 cells. Furthermore, in 6-OHDA-treated SH-SY5Y cells, GLNVA rescued the changes in condensed nuclear and apoptotic bodies, prevented the decrease in mitochondrial membrane potential, and reduced cells death. GLNVA also suppressed accumulation of iROS and up-regulated heme oxygenase-1 expression. 6-OHDA-induced overexpression of nNOS, i

  3. Nutrients, Microglia Aging, and Brain Aging

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    Zhou Wu

    2016-01-01

    Full Text Available As the life expectancy continues to increase, the cognitive decline associated with Alzheimer’s disease (AD becomes a big major issue in the world. After cellular activation upon systemic inflammation, microglia, the resident immune cells in the brain, start to release proinflammatory mediators to trigger neuroinflammation. We have found that chronic systemic inflammatory challenges induce differential age-dependent microglial responses, which are in line with the impairment of learning and memory, even in middle-aged animals. We thus raise the concept of “microglia aging.” This concept is based on the fact that microglia are the key contributor to the acceleration of cognitive decline, which is the major sign of brain aging. On the other hand, inflammation induces oxidative stress and DNA damage, which leads to the overproduction of reactive oxygen species by the numerous types of cells, including macrophages and microglia. Oxidative stress-damaged cells successively produce larger amounts of inflammatory mediators to promote microglia aging. Nutrients are necessary for maintaining general health, including the health of brain. The intake of antioxidant nutrients reduces both systemic inflammation and neuroinflammation and thus reduces cognitive decline during aging. We herein review our microglia aging concept and discuss systemic inflammation and microglia aging. We propose that a nutritional approach to controlling microglia aging will open a new window for healthy brain aging.

  4. Nutrients, Microglia Aging, and Brain Aging.

    Science.gov (United States)

    Wu, Zhou; Yu, Janchun; Zhu, Aiqin; Nakanishi, Hiroshi

    2016-01-01

    As the life expectancy continues to increase, the cognitive decline associated with Alzheimer's disease (AD) becomes a big major issue in the world. After cellular activation upon systemic inflammation, microglia, the resident immune cells in the brain, start to release proinflammatory mediators to trigger neuroinflammation. We have found that chronic systemic inflammatory challenges induce differential age-dependent microglial responses, which are in line with the impairment of learning and memory, even in middle-aged animals. We thus raise the concept of "microglia aging." This concept is based on the fact that microglia are the key contributor to the acceleration of cognitive decline, which is the major sign of brain aging. On the other hand, inflammation induces oxidative stress and DNA damage, which leads to the overproduction of reactive oxygen species by the numerous types of cells, including macrophages and microglia. Oxidative stress-damaged cells successively produce larger amounts of inflammatory mediators to promote microglia aging. Nutrients are necessary for maintaining general health, including the health of brain. The intake of antioxidant nutrients reduces both systemic inflammation and neuroinflammation and thus reduces cognitive decline during aging. We herein review our microglia aging concept and discuss systemic inflammation and microglia aging. We propose that a nutritional approach to controlling microglia aging will open a new window for healthy brain aging.

  5. Discovery of a novel, monocationic, small-molecule inhibitor of scrapie prion accumulation in cultured sheep microglia and Rov cells.

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    James B Stanton

    Full Text Available Prion diseases, including sheep scrapie, are neurodegenerative diseases with the fundamental pathogenesis involving conversion of normal cellular prion protein (PrP(C to disease-associated prion protein (PrP(Sc. Chemical inhibition of prion accumulation is widely investigated, often using rodent-adapted prion cell culture models. Using a PrP(Sc-specific ELISA we discovered a monocationic phenyl-furan-benzimidazole (DB772, which has previously demonstrated anti-pestiviral activity and represents a chemical category previously untested for anti-prion activity, that inhibited PrP(Sc accumulation and prion infectivity in primary sheep microglial cell cultures (PRNP 136VV/154RR/171QQ and Rov9 cultures (VRQ-ovinized RK13 cells. We investigated potential mechanisms of this anti-prion activity by evaluating PrP(C expression with quantitative RT-PCR and PrP ELISA, comparing the concentration-dependent anti-prion and anti-pestiviral effects of DB772, and determining the selectivity index. Results demonstrate at least an approximate two-log inhibition of PrP(Sc accumulation in the two cell systems and confirmed that the inhibition of PrP(Sc accumulation correlates with inhibition of prion infectivity. PRNP transcripts and total PrP protein concentrations within cell lysates were not decreased; thus, decreased PrP(C expression is not the mechanism of PrP(Sc inhibition. PrP(Sc accumulation was multiple logs more resistant than pestivirus to DB772, suggesting that the anti-PrP(Sc activity was independent of anti-pestivirus activity. The anti-PrP(Sc selectivity index in cell culture was approximately 4.6 in microglia and 5.5 in Rov9 cells. The results describe a new chemical category that inhibits ovine PrP(Sc accumulation in primary sheep microglia and Rov9 cells, and can be used for future studies into the treatment and mechanism of prion diseases.

  6. Neuroprotective function for ramified microglia in hippocampal excitotoxicity

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    Vinet Jonathan

    2012-01-01

    Full Text Available Abstract Background Most of the known functions of microglia, including neurotoxic and neuroprotective properties, are attributed to morphologically-activated microglia. Resting, ramified microglia are suggested to primarily monitor their environment including synapses. Here, we show an active protective role of ramified microglia in excitotoxicity-induced neurodegeneration. Methods Mouse organotypic hippocampal slice cultures were treated with N-methyl-D-aspartic acid (NMDA to induce excitotoxic neuronal cell death. This procedure was performed in slices containing resting microglia or slices that were chemically or genetically depleted of their endogenous microglia. Results Treatment of mouse organotypic hippocampal slice cultures with 10-50 μM N-methyl-D-aspartic acid (NMDA induced region-specific excitotoxic neuronal cell death with CA1 neurons being most vulnerable, whereas CA3 and DG neurons were affected less. Ablation of ramified microglia severely enhanced NMDA-induced neuronal cell death in the CA3 and DG region rendering them almost as sensitive as CA1 neurons. Replenishment of microglia-free slices with microglia restored the original resistance of CA3 and DG neurons towards NMDA. Conclusions Our data strongly suggest that ramified microglia not only screen their microenvironment but additionally protect hippocampal neurons under pathological conditions. Morphological activation of ramified microglia is thus not required to influence neuronal survival.

  7. Strategies for repair of white matter: influence of osmolarity and microglia on proliferation and apoptosis of oligodendrocyte precursor cells in different basal culture media.

    Science.gov (United States)

    Kleinsimlinghaus, Karolina; Marx, Romy; Serdar, Meray; Bendix, Ivo; Dietzel, Irmgard D

    2013-01-01

    The aim of the present study has been to obtain high yields of oligodendrocyte precursor cells (OPCs) in culture. This is a first step in facilitation of myelin repair. We show that, in addition to factors, known to promote proliferation, such as basic fibroblast growth factor (FGF-2) and platelet derived growth factor (PDGF) the choice of the basal medium exerts a significant influence on the yield of OPCs in cultures from newborn rats. During a culture period of up to 9 days we observed larger numbers of surviving cells in Dulbecco's Modified Eagle Medium (DMEM), and Roswell Park Memorial Institute Medium (RPMI) compared with Neurobasal Medium (NB). A larger number of A2B5-positive OPCs was found after 6 days in RPMI based media compared with NB. The percentage of bromodeoxyuridine (BrdU)-positive cells was largest in cultures maintained in DMEM and RPMI. The percentage of caspase-3 positive cells was largest in NB, suggesting that this medium inhibits OPC proliferation and favors apoptosis. A difference between NB and DMEM as well as RPMI is the reduced Na(+)-content. The addition of equiosmolar supplements of mannitol or NaCl to NB medium rescued the BrdU-incorporation rate. This suggested that the osmolarity influences the proliferation of OPCs. Plating density as well as residual microglia influence OPC survival, BrdU incorporation, and caspase-3 expression. We found, that high density cultures secrete factors that inhibit BrdU incorporation whereas the presence of additional microglia induces an increase in caspase-3 positive cells, indicative of enhanced apoptosis. An enhanced number of microglia could thus also explain the stronger inhibition of OPC differentiation observed in high density cultures in response to treatment with the cytokines TNF-α and IFN-γ. We conclude that a maximal yield of OPCs is obtained in a medium of an osmolarity higher than 280 mOsm plated at a relatively low density in the presence of as little microglia as technically

  8. Inflammation leads to distinct populations of extracellular vesicles from microglia

    DEFF Research Database (Denmark)

    Yang, Yiyi; Boza-Serrano, Antonio; Dunning, Christopher J.R.

    2018-01-01

    Background: Activated microglia play an essential role in inflammatory responses elicited in the central nervous system (CNS). Microglia-derived extracellular vesicles (EVs) are suggested to be involved in propagation of inflammatory signals and in the modulation of cell-to-cell communication...

  9. The neuropathological basis to the functional role of microglia/macrophages in gliomas.

    Science.gov (United States)

    Schiffer, Davide; Mellai, Marta; Bovio, Enrica; Annovazzi, Laura

    2017-09-01

    The paper wants to be a tracking shot of the main recent acquisitions on the function and significance of microglia/macrophages in gliomas. The observations have been principally carried out on in vitro cultures and on tumor transplants in animals. Contrary to what is deduced from microglia in non-neoplastic pathologic conditions of central nervous system (CNS), most conclusions indicate that microglia acts favoring tumor proliferation through an immunosuppression induced by glioma cells. By immunohistochemistry, different microglia phenotypes are recognized in gliomas, from ramified microglia to frank macrophagic aspect. One wonders whether the functional conclusions drawn from many microglia studies, but not in conditions of human pathology, apply to all the phenotypes recognizable in them. It is difficult to verify in human pathology a prognostic significance of microglia. Only CD163-positive microglia/macrophages inversely correlate with glioma patients' survival, whereas the total number of microglia does not change with the malignancy grade.

  10. Activated microglia induce bone marrow mesenchymal stem cells to produce glial cell-derived neurotrophic factor and protect neurons against oxygen-glucose deprivation injury

    Directory of Open Access Journals (Sweden)

    Bingke Lv

    2016-12-01

    Full Text Available In this study, we investigated interactions among microglia (MG, bone marrow mesenchymal stem cells (BMSCs and neurons in cerebral ischemia and the potential mechanisms using an in vitro oxygen-glucose deprivation (OGD model. Rat BMSCs were incubated with conditioned medium (CM from in vitro cultures of OGD-activated rat MG and murine BV2 MG cells. Effects of glial cell-derived neurotrophic factor (GDNF on rat neuron viability, apoptosis, lactate dehydrogenase (LDH leakage and mitochondrial membrane potential (MMP were analyzed in this model. OGD-activated MG promoted GDNF production by BMSCs (P < 0.01. TNFα, but not IL6 or IL1β, promoted GDNF production by BMSCs (P < 0.001. GDNF or CM pre-treated BMSCs elevated neuronal viability and suppressed apoptosis (P < 0.05 or P < 0.01; these effects were inhibited by the RET antibody. GDNF activated MEK/ERK and PI3K/AKT signaling but not JNK/c-JUN. Furthermore, GDNF upregulated B cell lymphoma 2 (BCL2 and heat shock 60 kDa protein 1 (HSP60 levels, suppressed LDH leakage, and promoted MMP. Thus, activated MG produce TNFα to stimulate GDNF production by BMSCs, which prevents and repairs OGD-induced neuronal injury, possibly via regulating MEK/ERK and PI3K/AKT signaling. These findings will facilitate the prevention and treatment of neuronal injury by cerebral ischemia.

  11. Huperzine A protects neural stem cells against Aβ-induced apoptosis in a neural stem cells and microglia co-culture system

    Science.gov (United States)

    Zhu, Ning; Lin, Jizong; Wang, Kewan; Wei, Meidan; Chen, Qingzhuang; Wang, Yong

    2015-01-01

    Objectives: This study aims to explore whether Huperzine A (HupA) could protect neural stem cells against amyloid beta-peptide Aβ induced apoptosis in a neural stem cells (NSCs) and microglia co-culture system. Methods: Rat NSCs and microglial cells were isolated, cultured and identified with immunofluorescence Assays (IFA). Co-culture systems of NSCs and microglial cells were employed using Transwell Permeable Supports. The effects of Aβ1-42 on NSCs were studied in 4 groups using co-culture systems: NSCs, Aβ+NSCs, co-culture and Aβ+co-culture groups. Bromodeoxyuridine (BrdU) incorporation and flow cytometry were utilized to assess the differences of proliferation, differentiation and apoptosis of NSCs between the groups. LQ test was performed to assess the amounts of IL-6, TNF-α and MIP-α secreted, and flow cytometry and Western blotting were used to assess apoptosis of NSCs and the expressions of Bcl-2 and Bax in each group. Results: IFA results showed that isolated rat NSCs were nestin-positive and microglial cells were CD11b/c-positive. Among all the groups, the Aβ+co-culture group has the lowest BrdU expression level, the lowest MAP2-positive, ChAT-positive cell counts and the highest NSC apoptosis rate. Smaller amounts of IL-6, TNF-α and MIP-α were being secreted by microglial cells in the HupA+Aβ+co-culture group compared with those in the Aβ+ co-culture group. Also the Bcl-2: Bax ratio was much higher in the HupA+Aβ+co-culture group than in the Aβ+co-culture group. Conclusions: HupA inhibits cell apoptosis through restraining microglia’s inflammatory response induced by Aβ1-42. PMID:26261518

  12. Nutritional and nanotechnological modulators of microglia

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    Dusica Maysinger

    2016-07-01

    Full Text Available Microglia are the essential responders to alimentary, pharmacological and nanotechnological immunomodulators. These neural cells play multiple roles as surveyors, sculptors, and guardians of essential parts of complex neural circuitries. Microglia can play dual roles in the central nervous system; they can be deleterious and/or protective. The immunomodulatory effects of alimentary components, gut microbiota and nanotechnological products have been investigated in microglia at the single cell level and in vivo using intravital imaging approaches, and different biochemical assays. This review highlights some of the emerging questions and topics from studies involving alimentation, microbiota, nanotechnological products, and associated problems in this area of research. Some of the advantages and limitations of in vitro and in vivo models used to study the neuromodulatory effects of these factors, as well as the merits and pitfalls of intravital imaging modalities employed are presented.

  13. Nuclear uptake of an amino-terminal fragment of apolipoprotein E4 promotes cell death and localizes within microglia of the Alzheimer's disease brain.

    Science.gov (United States)

    Love, Julia E; Day, Ryan J; Gause, Justin W; Brown, Raquel J; Pu, Xinzhu; Theis, Dustin I; Caraway, Chad A; Poon, Wayne W; Rahman, Abir A; Morrison, Brad E; Rohn, Troy T

    2017-01-01

    Although harboring the apolipoprotein E4 ( APOE4 ) allele is a well known risk factor in Alzheimer's disease (AD), the mechanism by which it contributes to disease risk remains elusive. To investigate the role of proteolysis of apoE4 as a potential mechanism, we designed and characterized a site-directed cleavage antibody directed at position D151 of the mature form of apoE4 and E3. Characterization of this antibody indicated a high specificity for detecting synthesized recombinant proteins corresponding to the amino acid sequences 1-151 of apoE3 and E4 that would generate the 17 kDa (p17) fragment. In addition, this antibody also detected a ~17 kDa amino-terminal fragment of apoE4 following incubation with collagenase and matrix metalloproteinase-9 (MMP-9), but did not react with full-length apoE4. Application of this amino-terminal apoE cleavage-fragment (nApoECFp17) antibody, revealed nuclear labeling within glial cells and labeling of a subset of neurofibrillary tangles in the human AD brain. A quantitative analysis indicated that roughly 80% of labeled nuclei were microglia. To confirm these findings, cultured BV2 microglia cells were incubated with the amino-terminal fragment of apoE4 corresponding to the cleavage site at D151. The results indicated efficient uptake of this fragment and trafficking to the nucleus that also resulted in significant cell death. In contrast, a similarly designed apoE3 fragment showed no toxicity and primarily localized within the cytoplasm. These data suggest a novel cleavage event by which apoE4 is cleaved by the extracellular proteases, collagenase and MMP-9, generating an amino-terminal fragment that is then taken up by microglia, traffics to the nucleus and promotes cell death. Collectively, these findings provide important mechanistic insights into the mechanism by which harboring the APOE4 allele may elevate dementia risk observed in AD.

  14. Noninvasive Quantification of Retinal Microglia Using Widefield Autofluorescence Imaging.

    Science.gov (United States)

    Kokona, Despina; Schneider, Nadia; Giannakaki-Zimmermann, Helena; Jovanovic, Joel; Ebneter, Andreas; Zinkernagel, Martin

    2017-04-01

    To validate widefield autofluorescence (AF) in vivo imaging of the retina in mice expressing green fluorescent protein (gfp) in microglia, and to monitor retinal microglia reconstitution in vivo after lethal irradiation and bone marrow transplantation. Transgenic Cx3cr1gfp/gfp and wildtype Balb/c mice were used in this study. A confocal scanning laser ophthalmoscope was used for AF imaging with a 55° and a widefield 102° lens. Intrasession reproducibility was assessed for each lens. To investigate reconstitution in vivo, bone marrow from Cx3cr1gfp/gfp mice was used to rescue lethally irradiated wildtype mice. Data were compared to confocal microscopy of retinal flat mounts. Both the 55° and the 102° lens produced high resolution images of retinal microglia with similar microglia density. However, compared to the 55° lens, the widefield 102° lens captured approximately 3.6 times more microglia cells (1515 ± 123 cells versus 445 ± 76 cells [mean ± SD], for 102° and 55°, respectively, P < 0.001). No statistical difference in the number of gfp positive cells within corresponding areas was observed within the same imaging session. Imaging of microglia reconstitution showed a similar time course compared to flat mount preparations with an excellent correlation between microglia cell numbers in AF and gfp-stained flat mounts (R = 0.92, P < 0.0001). Widefield AF imaging of mice with gfp expressing microglia can be used to quantify retinal microglia. In vivo microglia counts corresponded very well with ex vivo counts on retinal flat mounts. As such, AF imaging can largely replace ex vivo quantification.

  15. MafB antagonizes phenotypic alteration induced by GM-CSF in microglia

    Energy Technology Data Exchange (ETDEWEB)

    Koshida, Ryusuke, E-mail: rkoshida-myz@umin.ac.jp; Oishi, Hisashi, E-mail: hoishi@md.tsukuba.ac.jp; Hamada, Michito; Takahashi, Satoru

    2015-07-17

    Microglia are tissue-resident macrophages which are distributed throughout the central nervous system (CNS). Recent studies suggest that microglia are a unique myeloid population distinct from peripheral macrophages in terms of origin and gene expression signature. Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic cytokine regulating myeloid development, has been shown to stimulate proliferation and alter phenotype of microglia in vitro. However, how its signaling is modulated in microglia is poorly characterized. MafB, a bZip transcriptional factor, is highly expressed in monocyte-macrophage lineage cells including microglia, although its role in microglia is largely unknown. We investigated the crosstalk between GM-CSF signaling and MafB by analyzing primary microglia. We found that Mafb-deficient microglia grew more rapidly than wild-type microglia in response to GM-CSF. Moreover, the expression of genes associated with microglial differentiation was more downregulated in Mafb-deficient microglia cultured with GM-CSF. Notably, such differences between the genotypes were not observed in the presence of M-CSF. In addition, we found that Mafb-deficient microglia cultured with GM-CSF barely extended their membrane protrusions, probably due to abnormal activation of RhoA, a key regulator of cytoskeletal remodeling. Altogether, our study reveals that MafB is a negative regulator of GM-CSF signaling in microglia. These findings could provide new insight into the modulation of cytokine signaling by transcription factors in microglia. - Highlights: • GM-CSF alters the phenotype of microglia in vitro more potently than M-CSF. • Transcription factor MafB antagonizes the effect of GM-CSF on microglia in vitro. • MafB deficiency leads to RhoA activation in microglia in response to GM-CSF. • We show for the first time the function of MafB in microglia.

  16. ifn-γ-dependent secretion of IL-10 from Th1 cells and microglia/macrophages contributes to functional recovery after spinal cord injury

    Science.gov (United States)

    Ishii, H; Tanabe, S; Ueno, M; Kubo, T; Kayama, H; Serada, S; Fujimoto, M; Takeda, K; Naka, T; Yamashita, T

    2013-01-01

    Transfer of type-1 helper T-conditioned (Th1-conditioned) cells promotes functional recovery with enhanced axonal remodeling after spinal cord injury (SCI). This study explored the molecular mechanisms underlying the beneficial effects of pro-inflammatory Th1-conditioned cells after SCI. The effect of Th1-conditioned cells from interferon-γ (ifn-γ) knockout mice (ifn-γ−/− Th1 cells) on the recovery after SCI was reduced. Transfer of Th1-conditioned cells led to the activation of microglia (MG) and macrophages (MΦs), with interleukin 10 (IL-10) upregulation. This upregulation of IL-10 was reduced when ifn-γ−/− Th1 cells were transferred. Intrathecal neutralization of IL-10 in the spinal cord attenuated the effects of Th1-conditioned cells. Further, IL-10 is robustly secreted from Th1-conditioned cells in an ifn-γ-dependent manner. Th1-conditioned cells from interleukin 10 knockout (il-10−/−) mice had no effects on recovery from SCI. These findings demonstrate that ifn-γ-dependent secretion of IL-10 from Th1 cells, as well as native MG/MΦs, is required for the promotion of motor recovery after SCI. PMID:23828573

  17. Small molecule activators of the Nrf2-HO-1 antioxidant axis modulate heme metabolism and inflammation in BV2 microglia cells.

    Science.gov (United States)

    Foresti, Roberta; Bains, Sandip K; Pitchumony, Tamil Selvi; de Castro Brás, Lisandra E; Drago, Filippo; Dubois-Randé, Jean-Luc; Bucolo, Claudio; Motterlini, Roberto

    2013-10-01

    The nuclear factor erythroid derived 2-related factor 2 (Nrf2) and the antioxidant protein heme oxygenase-1 (HO-1) are crucial components of the cellular stress response. These two systems work together to combat oxidative stress and inflammation and are attractive drug targets for counteracting different pathologies, including neuroinflammation. We aimed to identify the most effective Nrf2/HO-1 activators that modulate the inflammatory response in microglia cells. In the present study, we searched the literature and selected 56 compounds reported to activate Nrf2 or HO-1 and analyzed them for HO-1 induction at 6 and 24h and cytotoxicity in BV2 microglial cells in vitro. Approximately 20 compounds up-regulated HO-1 at the concentrations tested (5-20 μM) with carnosol, supercurcumin, cobalt protoporphyrin-IX and dimethyl fumarate exhibiting the best induction/low cytotoxicity profile. Up-regulation of HO-1 by some compounds resulted in increased cellular bilirubin levels but did not augment the expression of proteins involved in heme synthesis (ALAS 1) or biliverdin reductase. Bilirubin production by HO-1 inducers correlated with their potency in inhibiting nitrite production after challenge with interferon-γ (INF-γ) or lipopolysaccharide (LPS). The compounds down-regulated the inflammatory response (TNF-α, PGE2 and nitrite) more strongly in cells challenged with INF-γ than LPS, and silencing HO-1 or Nrf2 with shRNA differentially affected the levels of inflammatory markers. These findings indicate that some small activators of Nrf2/HO-1 are effective modulators of microglia inflammation and highlight the chemical scaffolds that can serve for the synthesis of potent new derivatives to counteract neuroinflammation and neurodegeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. The ischemic environment drives microglia and macrophage function

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    Stefano eFumagalli

    2015-04-01

    Full Text Available Cells of myeloid origin such as microglia and macrophages act at the crossroads of several inflammatory mechanisms during pathophysiology. Besides pro-inflammatory activity (M1 polarization, myeloid cells acquire protective functions (M2 and participate in the neuroprotective innate mechanisms after brain injury. Experimental research is making considerable efforts to understand the rules that regulate the balance between toxic and protective brain innate immunity. Environmental changes affects microglia/macrophage functions. Hypoxia can affect myeloid cell distribution, activity and phenotype. With their intrinsic differences, microglia and macrophages respond differently to hypoxia, the former depending on ATP to activate, the latter switching to anaerobic metabolism and adapting to hypoxia. Myeloid cell functions include homeostasis control, damage-sensing activity, chemotaxis and phagocytosis, all distinctive features of these cells. Specific markers and morphologies enable to recognize each functional state. To ensure homeostasis and activate when needed, microglia/macrophage physiology is finely tuned. Microglia are controlled by several neuron-derived components, including contact-dependent inhibitory signals and soluble molecules. Changes in this control can cause chronic activation or priming with specific functional consequences. Strategies such as stem cell treatment may enhance microglia protective polarization. This review presents data from the literature that has greatly advanced our understanding of myeloid cell action in brain injury. We discuss the selective responses of microglia and macrophages to hypoxia after stroke and review relevant markers with the aim of defining the different subpopulations of myeloid cells that are recruited to the injured site. We also cover the functional consequences of chronically active microglia and review pivotal works on microglia regulation that offer new therapeutic possibilities for acute

  19. The Lifespan and Turnover of Microglia in the Human Brain

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    Pedro Réu

    2017-07-01

    Full Text Available The hematopoietic system seeds the CNS with microglial progenitor cells during the fetal period, but the subsequent cell generation dynamics and maintenance of this population have been poorly understood. We report that microglia, unlike most other hematopoietic lineages, renew slowly at a median rate of 28% per year, and some microglia last for more than two decades. Furthermore, we find no evidence for the existence of a substantial population of quiescent long-lived cells, meaning that the microglia population in the human brain is sustained by continuous slow turnover throughout adult life.

  20. Regulation of vacuolar H+-ATPase in microglia by RANKL

    International Nuclear Information System (INIS)

    Serrano, Eric M.; Ricofort, Ryan D.; Zuo, Jian; Ochotny, Noelle; Manolson, Morris F.; Holliday, L. Shannon

    2009-01-01

    Vacuolar H + -ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPases play specialized roles in certain cell types, a capacity that is linked to cell type selective expression of isoforms of some of the subunits. We detected low levels of the a3 isoform of the a-subunit in mouse brain extracts. Examination of various brain-derived cell types by immunoblotting showed a3 was expressed in the N9 microglia cell line and in primary microglia, but not in other cell types. The expression of a3 in osteoclasts requires stimulation by Receptor Activator of Nuclear Factor κB-ligand (RANKL). We found that Receptor Activator of Nuclear Factor κB (RANK) was expressed by microglia. Stimulation of microglia with RANKL triggered increased expression of a3. V-ATPases in microglia were shown to bind microfilaments, and stimulation with RANKL increased the proportion of V-ATPase associated with the detergent-insoluble cytoskeletal fraction and with actin. In summary, microglia express the a3-subunit of V-ATPase. The expression of a3 and the interaction between V-ATPases and microfilaments was modulated by RANKL. These data suggest a novel molecular pathway for regulating microglia.

  1. NADPH oxidases in Microglia oxidant production

    DEFF Research Database (Denmark)

    Haslund-Vinding, J; McBean, G; Jaquet, V

    2017-01-01

    inhibitors. Finally, we review the recent literature on NOX and other sources of ROS that are involved in activation of the inflammasome and discuss the potential influence of microglia-derived oxidants on neurogenesis, neural differentiation and culling of surplus progenitor cells. The degree to which...

  2. Neuron-microglia interactions in mental health disorders: 'For better, and for worse'

    Directory of Open Access Journals (Sweden)

    Eric S Wohleb

    2016-11-01

    Full Text Available Persistent cognitive and behavioral symptoms that characterize many mental health disorders arise from impaired neuroplasticity in several key corticolimbic brain regions. Recent evidence suggest that reciprocal neuron-microglia interactions shape neuroplasticity during physiological conditions, implicating microglia in the neurobiology of mental health disorders. Neuron-microglia interactions are modulated by several molecular and cellular pathways and dysregulation of these pathways often have neurobiological consequences, including aberrant neuronal responses and microglia activation. The interactions between neurons and microglia have implications for mental health disorders as rodent stress models cause concomitant neuronal dystrophy and alterations in microglia morphology and function. In this context, functional changes in microglia may be indicative of an immune state termed parainflammation in which tissue-resident macrophages (i.e., microglia respond to malfunctioning cells by initiating modest inflammation in an attempt to restore homeostasis. Thus, aberrant neuronal activity and release of damage-associated signals during repeated stress exposure may contribute to functional changes in microglia and resultant parainflammation. Furthermore, accumulating evidence shows that uncoupling neuron-microglia interactions may contribute to altered neuroplasticity and associated anxiety- or depressive-like behaviors. Additional work shows that microglia have varied phenotypes in specific brain regions, which may underlie divergent neuroplasticity observed in corticolimbic structures following stress exposure. These findings indicate that neuron-microglia interactions are critical mediators of the interface between adaptive, homeostatic neuronal function and the neurobiology of mental health disorders.

  3. Astrocytes play a key role in activation of microglia by persistent Borna disease virus infection

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    Sauder Christian

    2008-11-01

    Full Text Available Abstract Neonatal Borna disease virus (BDV infection of the rat brain is associated with microglial activation and damage to certain neuronal populations. Since persistent BDV infection of neurons is nonlytic in vitro, activated microglia have been suggested to be responsible for neuronal cell death in vivo. However, the mechanisms of activation of microglia in neonatally BDV-infected rat brains remain unclear. Our previous studies have shown that activation of microglia by BDV in culture requires the presence of astrocytes as neither the virus nor BDV-infected neurons alone activate microglia. Here, we evaluated the mechanisms whereby astrocytes can contribute to activation of microglia in neuron-glia-microglia mixed cultures. We found that persistent infection of neuronal cells leads to activation of uninfected astrocytes as measured by elevated expression of RANTES. Activation of astrocytes then produces activation of microglia as evidenced by increased formation of round-shaped, MHCI-, MHCII- and IL-6-positive microglia cells. Our analysis of possible molecular mechanisms of activation of astrocytes and/or microglia in culture indicates that the mediators of activation may be soluble heat-resistant, low molecular weight factors. The findings indicate that astrocytes may mediate activation of microglia by BDV-infected neurons. The data are consistent with the hypothesis that microglia activation in the absence of neuronal damage may represent initial steps in the gradual neurodegeneration observed in brains of neonatally BDV-infected rats.

  4. Microglia Modulate Wiring of the Embryonic Forebrain

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    Paola Squarzoni

    2014-09-01

    Full Text Available Dysfunction of microglia, the tissue macrophages of the brain, has been associated with the etiology of several neuropsychiatric disorders. Consistently, microglia have been shown to regulate neurogenesis and synaptic maturation at perinatal and postnatal stages. However, microglia invade the brain during mid-embryogenesis and thus could play an earlier prenatal role. Here, we show that embryonic microglia, which display a transiently uneven distribution, regulate the wiring of forebrain circuits. Using multiple mouse models, including cell-depletion approaches and cx3cr1−/−, CR3−/−, and DAP12−/− mutants, we find that perturbing microglial activity affects the outgrowth of dopaminergic axons in the forebrain and the laminar positioning of subsets of neocortical interneurons. Since defects in both dopamine innervation and cortical networks have been linked to neuropsychiatric diseases, our study provides insights into how microglial dysfunction can impact forebrain connectivity and reveals roles for immune cells during normal assembly of brain circuits.

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

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    Walther Haenseler

    2017-06-01

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

  6. Microglia from neurogenic and non-neurogenic regions display differential proliferative potential and neuroblast support

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    Gregory Paul Marshall

    2014-07-01

    Full Text Available Microglia isolated from the neurogenic subependymal zone (SEZ and hippocampus (HC are capable of massive in vitro population expansion that is not possible with microglia isolated from non-neurogenic regions. We asked if this regional heterogeneity in microglial proliferative capacity is cell intrinsic, or is conferred by interaction with respective neurogenic or non-neurogenic niches. By combining SEZ and cerebral cortex (CTX primary tissue dissociates to generate heterospatial cultures, we find that exposure to the SEZ environment does not enhance CTX microglia expansion; however, the CTX environment exerts a suppressive effect on SEZ microglia expansion. Furthermore, addition of purified donor SEZ microglia to either CTX- or SEZ-derived cultures suppresses the expansion of host microglia, while the addition of donor CTX microglia enhances the over-all microglia yield. These data suggest that SEZ and CTX microglia possess intrinsic, spatially restricted characteristics that are independent of their in vitro environment, and that they represent unique and functionally distinct populations. Finally, we determined that the repeated supplementation of neurogenic SEZ cultures with expanded SEZ microglia allows for sustained levels of inducible neurogenesis, provided that the ratio of microglia to total cells remains within a fairly narrow range.

  7. Microglia and neuroprotection: implications for Alzheimer's disease.

    Science.gov (United States)

    Streit, Wolfgang J

    2005-04-01

    The first part of this paper summarizes some of the key observations from experimental work in animals that support a role of microglia as neuroprotective cells after acute neuronal injury. These studies point towards an important role of neuronal-microglial crosstalk in the facilitation of neuroprotection. Conceptually, injured neurons are thought to generate rescue signals that trigger microglial activation and, in turn, activated microglia produce trophic or other factors that help damaged neurons recover from injury. Against this background, the second part of this paper summarizes recent work from postmortem studies conducted in humans that have revealed the occurrence of senescent, or dystrophic, microglial cells in the aged and Alzheimer's disease brain. These findings suggest that microglial cells become increasingly dysfunctional with advancing age and that a loss of microglial cell function may involve a loss of neuroprotective properties that could contribute to the development of aging-related neurodegeneration.

  8. Developmental stage of oligodendrocytes determines their response to activated microglia in vitro

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    Bresnahan Jacqueline C

    2007-11-01

    Full Text Available Abstract Background Oligodendrocyte progenitor cells (OPCs and mature oligodendrocytes are both lost in central nervous system injury and disease. Activated microglia may play a role in OPC and oligodendrocyte loss or replacement, but it is not clear how the responses of OPCs and oligodendrocytes to activated microglia differ. Methods OPCs and microglia were isolated from rat cortex. OPCs were induced to differentiate into oligodendrocytes with thyroid hormone in defined medium. For selected experiments, microglia were added to OPC or oligodendrocyte cultures. Lipopolysaccharide was used to activate microglia and microglial activation was confirmed by TNFα ELISA. Cell survival was assessed with immunocytochemistry and cell counts. OPC proliferation and oligodendrocyte apoptosis were also assessed. Results OPCs and oligodendrocytes displayed phenotypes representative of immature and mature oligodendrocytes, respectively. Activated microglia reduced OPC survival, but increased survival and reduced apoptosis of mature oligodendrocytes. Activated microglia also underwent cell death themselves. Conclusion Activated microglia may have divergent effects on OPCs and mature oligodendrocytes, reducing OPC survival and increasing mature oligodendrocyte survival. This may be of importance because activated microglia are present in several disease states where both OPCs and mature oligodendrocytes are also reacting to injury. Activated microglia may simultaneously have deleterious and helpful effects on different cells after central nervous system injury.

  9. Involvement of Heme Oxygenase-1 Induction in the Cytoprotective and Immunomodulatory Activities of Viola patrinii in Murine Hippocampal and Microglia Cells

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    Bin Li

    2012-01-01

    Full Text Available A number of diseases that lead to injury of the central nervous system are caused by oxidative stress and inflammation in the brain. In this study, NNMBS275, consisting of the ethanol extract of Viola patrinii, showed potent antioxidative and anti-inflammatory activity in murine hippocampal HT22 cells and BV2 microglia. NNMBS275 increased cellular resistance to oxidative injury caused by glutamate-induced neurotoxicity and reactive oxygen species generation in HT22 cells. In addition, the anti-inflammatory effects of NNMBS275 were demonstrated by the suppression of proinflammatory mediators, including proinflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2 and cytokines (tumor necrosis factor-α and interleukin-1β. Furthermore, we found that the neuroprotective and anti-inflammatory effects of NNMBS275 were linked to the upregulation of nuclear transcription factor-E2-related factor 2-dependent expression of heme oxygenase-1 in HT22 and BV2 cells. These results suggest that NNMBS275 possesses therapeutic potential against neurodegenerative diseases that are induced by oxidative stress and neuroinflammation.

  10. Liposomal TriCurin, A Synergistic Combination of Curcumin, Epicatechin Gallate and Resveratrol, Repolarizes Tumor-Associated Microglia/Macrophages, and Eliminates Glioblastoma (GBM) and GBM Stem Cells.

    Science.gov (United States)

    Mukherjee, Sumit; Baidoo, Juliet N E; Sampat, Samay; Mancuso, Andrew; David, Lovena; Cohen, Leah S; Zhou, Shuiqin; Banerjee, Probal

    2018-01-18

    Glioblastoma (GBM) is a deadly brain tumor with a current mean survival of 12-15 months. Despite being a potent anti-cancer agent, the turmeric ingredient curcumin (C) has limited anti-tumor efficacy in vivo due to its low bioavailability. We have reported earlier a strategy involving the use two other polyphenols, epicatechin gallate (E) from green tea and resveratrol (R) from red grapes at a unique, synergistic molar ratio with C (C:E:R: 4:1:12.5, termed TriCurin) to achieve superior potency against HPV+ tumors than C alone at C:E:R (μM): 32:8:100 (termed 32 μM+ TriCurin). We have now prepared liposomal TriCurin (TrLp) and demonstrated that TrLp boosts activated p53 in cultured GL261 mouse GBM cells to trigger apoptosis of GBM and GBM stem cells in vitro. TrLp administration into mice yielded a stable plasma concentration of 210 nM C for 60 min, which, though sub-lethal for cultured GL261 cells, was able to cause repolarization of M2-like tumor (GBM)-associated microglia/macrophages to the tumoricidal M1-like phenotype and intra-GBM recruitment of activated natural killer cells. The intratumor presence of such tumoricidal immune cells was associated with concomitant suppression of tumor-load, and apoptosis of GBM and GBM stem cells. Thus, TrLp is a potential onco-immunotherapeutic agent against GBM tumors.

  11. Liposomal TriCurin, A Synergistic Combination of Curcumin, Epicatechin Gallate and Resveratrol, Repolarizes Tumor-Associated Microglia/Macrophages, and Eliminates Glioblastoma (GBM and GBM Stem Cells

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    Sumit Mukherjee

    2018-01-01

    Full Text Available Glioblastoma (GBM is a deadly brain tumor with a current mean survival of 12–15 months. Despite being a potent anti-cancer agent, the turmeric ingredient curcumin (C has limited anti-tumor efficacy in vivo due to its low bioavailability. We have reported earlier a strategy involving the use two other polyphenols, epicatechin gallate (E from green tea and resveratrol (R from red grapes at a unique, synergistic molar ratio with C (C:E:R: 4:1:12.5, termed TriCurin to achieve superior potency against HPV+ tumors than C alone at C:E:R (μM: 32:8:100 (termed 32 μM+ TriCurin. We have now prepared liposomal TriCurin (TrLp and demonstrated that TrLp boosts activated p53 in cultured GL261 mouse GBM cells to trigger apoptosis of GBM and GBM stem cells in vitro. TrLp administration into mice yielded a stable plasma concentration of 210 nM C for 60 min, which, though sub-lethal for cultured GL261 cells, was able to cause repolarization of M2-like tumor (GBM-associated microglia/macrophages to the tumoricidal M1-like phenotype and intra-GBM recruitment of activated natural killer cells. The intratumor presence of such tumoricidal immune cells was associated with concomitant suppression of tumor-load, and apoptosis of GBM and GBM stem cells. Thus, TrLp is a potential onco-immunotherapeutic agent against GBM tumors.

  12. Microglia Responses in Acute and Chronic Neurological Diseases: What Microglia-Specific Transcriptomic Studies Taught (and did Not Teach Us

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    Hélène E. Hirbec

    2017-07-01

    Full Text Available Over the last decade, microglia have been acknowledged to be key players in central nervous system (CNS under both physiological and pathological conditions. They constantly survey the CNS environment and as immune cells, in pathological contexts, they provide the first host defense and orchestrate the immune response. It is well recognized that under pathological conditions microglia have both sequential and simultaneous, beneficial and detrimental effects. Cell-specific transcriptomics recently became popular in Neuroscience field allowing concurrent monitoring of the expression of numerous genes in a given cell population. Moreover, by comparing two or more conditions, these approaches permit to unbiasedly identify deregulated genes and pathways. A growing number of studies have thus investigated microglial transcriptome remodeling over the course of neuropathological conditions and highlighted the molecular diversity of microglial response to different diseases. In the present work, we restrict our review to microglia obtained directly from in vivo samples and not cell culture, and to studies using whole-genome strategies. We first critically review the different methods developed to decipher microglia transcriptome. In particular, we compare advantages and drawbacks of flow cytometry and laser microdissection to isolate pure microglia population as well as identification of deregulated microglial genes obtained via RNA sequencing (RNA-Seq vs. microarrays approaches. Second, we summarize insights obtained from microglia transcriptomes in traumatic brain and spinal cord injuries, pain and more chronic neurological conditions including Amyotrophic lateral sclerosis (ALS, Alzheimer disease (AD and Multiple sclerosis (MS. Transcriptomic responses of microglia in other non-neurodegenerative CNS disorders such as gliomas and sepsis are also addressed. Third, we present a comparison of the most activated pathways in each neuropathological condition

  13. Microglia kill amyloid-beta1-42 damaged neurons by a CD14-dependent process

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    Bate, Clive; Veerhuis, Robert; Eikelenboom, Piet; Williams, Alun

    2004-01-01

    Activated microglia are closely associated with neuronal damage in Alzheimer's disease. In the present study, neurons exposed to low concentrations of amyloid-beta1-42, a toxic fragment of the amyloid-beta protein, were killed by microglia in a process that required cell-cell contact. Pre-treating

  14. ATP Modifies the Proteome of Extracellular Vesicles Released by Microglia and Influences Their Action on Astrocytes

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    Francesco Drago

    2017-12-01

    Full Text Available Extracellular ATP is among molecules promoting microglia activation and inducing the release of extracellular vesicles (EVs, which are potent mediators of intercellular communication between microglia and the microenvironment. We previously showed that EVs produced under ATP stimulation (ATP-EVs propagate a robust inflammatory reaction among astrocytes and microglia in vitro and in mice with subclinical neuroinflammation (Verderio et al., 2012. However, the proteome of EVs released upon ATP stimulation has not yet been elucidated. In this study we applied a label free proteomic approach to characterize the proteome of EVs released constitutively and during microglia activation with ATP. We show that ATP drives sorting in EVs of a set of proteins implicated in cell adhesion/extracellular matrix organization, autophagy-lysosomal pathway and cellular metabolism, that may influence the response of recipient astrocytes to EVs. These data provide new clues to molecular mechanisms involved in microglia response to ATP and in microglia signaling to the environment via EVs.

  15. Recent Advances in the Study of Bipolar/Rod-Shaped Microglia and their Roles in Neurodegeneration

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    Ngan Pan Bennett Au

    2017-05-01

    Full Text Available Microglia are the resident immune cells of the central nervous system (CNS and they contribute to primary inflammatory responses following CNS injuries. The morphology of microglia is closely associated with their functional activities. Most previous research efforts have attempted to delineate the role of ramified and amoeboid microglia in the pathogenesis of neurodegenerative diseases. In addition to ramified and amoeboid microglia, bipolar/rod-shaped microglia were first described by Franz Nissl in 1899 and their presence in the brain was closely associated with the pathology of infectious diseases and sleeping disorders. However, studies relating to bipolar/rod-shaped microglia are very limited, largely due to the lack of appropriate in vitro and in vivo experimental models. Recent studies have reported the formation of bipolar/rod-shaped microglia trains in in vivo models of CNS injury, including diffuse brain injury, focal transient ischemia, optic nerve transection and laser-induced ocular hypertension (OHT. These bipolar/rod-shaped microglia formed end-to-end alignments in close proximity to the adjacent injured axons, but they showed no interactions with blood vessels or other types of glial cell. Recent studies have also reported on a highly reproducible in vitro culture model system to enrich bipolar/rod-shaped microglia that acts as a powerful tool with which to characterize this form of microglia. The molecular aspects of bipolar/rod-shaped microglia are of great interest in the field of CNS repair. This review article focuses on studies relating to the morphology and transformation of microglia into the bipolar/rod-shaped form, along with the differential gene expression and spatial distribution of bipolar/rod-shaped microglia in normal and pathological CNSs. The spatial arrangement of bipolar/rod-shaped microglia is crucial in the reorganization and remodeling of neuronal and synaptic circuitry following CNS injuries. Finally, we

  16. Dopamine inhibits lipopolysaccharide-induced nitric oxide production through the formation of dopamine quinone in murine microglia BV-2 cells

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    Yasuhiro Yoshioka

    2016-02-01

    Full Text Available Dopamine (DA has been suggested to modulate functions of glial cells including microglial cells. To reveal the regulatory role of DA in microglial function, in the present study, we investigated the effect of DA on lipopolysaccharide (LPS-induced nitric oxide (NO production in murine microglial cell line BV-2. Pretreatment with DA for 24 h concentration-dependently attenuated LPS-induced NO production in BV-2 cells. The inhibitory effect of DA on LPS-induced NO production was not inhibited by SCH-23390 and sulpiride, D1-like and D2-like DA receptor antagonists, respectively. In addition, pretreatment with (−-(6aR,12bR-4,6,6a,7,8,12b-Hexahydro-7-methylindolo[4,3-a]phenanthridin (CY 208–243 and bromocriptine, D1-like and D2-like DA receptor agonists, respectively, did not affect the LPS-induced NO production. N-Acetylcysteine, which inhibits DA oxidation, completely inhibited the effect of DA. Tyrosinase, which catalyzes the oxidation of DA to DA quionone (DAQ, accelerated the inhibitory effect of DA on LPS-induced NO production. These results suggest that DA attenuates LPS-induced NO production through the formation of DAQ in BV-2 cells.

  17. Microglia change from a reactive to an age-like phenotype with the time in culture

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    Caldeira, Cláudia; Oliveira, Ana F.; Cunha, Carolina; Vaz, Ana R.; Falcão, Ana S.; Fernandes, Adelaide; Brites, Dora

    2014-01-01

    Age-related neurodegenerative diseases have been associated with chronic neuroinflammation and microglia activation. However, cumulative evidence supports that inflammation only occurs at an early stage once microglia change the endogenous characteristics with aging and switch to irresponsive/senescent and dystrophic phenotypes with disease progression. Thus, it will be important to have the means to assess the role of reactive and aged microglia when studying advanced brain neurodegeneration processes and age-associated related disorders. Yet, most studies are done with microglia from neonates since there are no adequate means to isolate degenerating microglia for experimentation. Indeed, only a few studies report microglia isolation from aged animals, using either short-term cultures or high concentrations of mitogens in the medium, which trigger microglia reactivity. The purpose of this study was to develop an experimental process to naturally age microglia after isolation from neonatal mice and to characterize the cultured cells at 2 days in vitro (DIV), 10 DIV, and 16 DIV. We found that 2 DIV (young) microglia had predominant amoeboid morphology and markers of stressed/reactive phenotype. In contrast, 16 DIV (aged) microglia evidenced ramified morphology and increased matrix metalloproteinase (MMP)-2 activation, as well as reduced MMP-9, glutamate release and nuclear factor kappa-B activation, in parallel with decreased expression of Toll-like receptor (TLR)-2 and TLR-4, capacity to migrate and phagocytose. These findings together with the reduced expression of microRNA (miR)-124, and miR-155, decreased autophagy, enhanced senescence associated beta-galactosidase activity and elevated miR-146a expression, are suggestive that 16 DIV cells mainly correspond to irresponsive/senescent microglia. Data indicate that the model represent an opportunity to understand and control microglial aging, as well as to explore strategies to recover microglia surveillance

  18. Key Aging-Associated Alterations in Primary Microglia Response to Beta-Amyloid Stimulation

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    Cláudia Caldeira

    2017-08-01

    Full Text Available Alzheimer’s disease (AD is characterized by a progressive cognitive decline and believed to be driven by the self-aggregation of amyloid-β (Aβ peptide into oligomers and fibrils that accumulate as senile plaques. It is widely accepted that microglia-mediated inflammation is a significant contributor to disease pathogenesis; however, different microglia phenotypes were identified along AD progression and excessive Aβ production was shown to dysregulate cell function. As so, the contribution of microglia to AD pathogenesis remains to be elucidated. In this study, we wondered if isolated microglia cultured for 16 days in vitro (DIV would react differentially from the 2 DIV cells upon treatment with 1000 nM Aβ1–42 for 24 h. No changes in cell viability were observed and morphometric alterations associated to microglia activation, such as volume increase and process shortening, were obvious in 2 DIV microglia, but less evident in 16 DIV cells. These cells showed lower phagocytic, migration and autophagic properties after Aβ treatment than the 2 DIV cultured microglia. Reduced phagocytosis may derive from increased CD33 expression, reduced triggering receptor expressed on myeloid cells 2 (TREM2 and milk fat globule-EGF factor 8 protein (MFG-E8 levels, which were mainly observed in 16 DIV cells. Activation of inflammatory mediators, such as high mobility group box 1 (HMGB1 and pro-inflammatory cytokines, as well as increased expression of Toll-like receptor 2 (TLR2, TLR4 and fractalkine/CX3C chemokine receptor 1 (CX3CR1 cell surface receptors were prominent in 2 DIV microglia, while elevation of matrix metalloproteinase 9 (MMP9 was marked in 16 DIV cells. Increased senescence-associated β-galactosidase (SA-β-gal and upregulated miR-146a expression that were observed in 16 DIV cells showed to increase by Aβ in 2 DIV microglia. Additionally, Aβ downregulated miR-155 and miR-124, and reduced the CD11b+ subpopulation in 2 DIV microglia, while

  19. Profiling of cytosolic and mitochondrial H2O2 production using the H2O2-sensitive protein HyPer in LPS-induced microglia cells.

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    Park, Junghyung; Lee, Seunghoon; Lee, Hyun-Shik; Lee, Sang-Rae; Lee, Dong-Seok

    2017-07-27

    Dysregulation of the production of pro-inflammatory mediators in microglia exacerbates the pathologic process of neurodegenerative disease. ROS actively affect microglia activation by regulating transcription factors that control the expression of pro-inflammatory genes. However, accurate information regarding the function of ROS in different subcellular organelles has not yet been established. Here, we analyzed the pattern of cytosolic and mitochondrial H 2 O 2 formation in LPS-activated BV-2 microglia using the H 2 O 2- sensitive protein HyPer targeted to specific subcellular compartments. Our results show that from an early time, cytosolic H 2 O 2 started increasing constantly, whereas mitochondrial H 2 O 2 rapidly increased later. In addition, we found that MAPK affected cytosolic H 2 O 2 , but not mitochondrial H 2 O 2 . Consequently, our study provides the basic information about subcellular H 2 O 2 generation in activated microglia, and a useful tool for investigating molecular targets that can modulate neuroinflammatory responses. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Maternal inflammation induces immune activation of fetal microglia and leads to disrupted microglia immune responses, behavior, and learning performance in adulthood.

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    Schaafsma, Wandert; Basterra, Laura Bozal; Jacobs, Sabrina; Brouwer, Nieske; Meerlo, Peter; Schaafsma, Anne; Boddeke, Erik W G M; Eggen, Bart J L

    2017-10-01

    Maternal inflammation during pregnancy can have detrimental effects on embryonic development that persist during adulthood. However, the underlying mechanisms and insights in the responsible cell types are still largely unknown. Here we report the effect of maternal inflammation on fetal microglia, the innate immune cells of the central nervous system (CNS). In mice, a challenge with LPS during late gestation stages (days 15-16-17) induced a pro-inflammatory response in fetal microglia. Adult whole brain microglia of mice that were exposed to LPS during embryonic development displayed a persistent reduction in pro-inflammatory activation in response to a re-challenge with LPS. In contrast, hippocampal microglia of these mice displayed an increased inflammatory response to an LPS re-challenge. In addition, a reduced expression of brain-derived neurotrophic factor (BDNF) was observed in hippocampal microglia of LPS-offspring. Microglia-derived BDNF has been shown to be important for learning and memory processes. In line with these observations, behavioral- and learning tasks with mice that were exposed to maternal inflammation revealed reduced home cage activity, reduced anxiety and reduced learning performance in a T-maze. These data show that exposure to maternal inflammation during late gestation results in long term changes in microglia responsiveness during adulthood, which is different in nature in hippocampus compared to total brain microglia. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Activation of microglial cells triggers a release of brain-derived neurotrophic factor (BDNF) inducing their proliferation in an adenosine A2A receptor-dependent manner: A2A receptor blockade prevents BDNF release and proliferation of microglia

    Science.gov (United States)

    2013-01-01

    Background Brain-derived neurotrophic factor (BDNF) has been shown to control microglial responses in neuropathic pain. Since adenosine A2A receptors (A2ARs) control neuroinflammation, as well as the production and function of BDNF, we tested to see if A2AR controls the microglia-dependent secretion of BDNF and the proliferation of microglial cells, a crucial event in neuroinflammation. Methods Murine N9 microglial cells were challenged with lipopolysaccharide (LPS, 100 ng/mL) in the absence or in the presence of the A2AR antagonist, SCH58261 (50 nM), as well as other modulators of A2AR signaling. The BDNF cellular content and secretion were quantified by Western blotting and ELISA, A2AR density was probed by Western blotting and immunocytochemistry and cell proliferation was assessed by BrdU incorporation. Additionally, the A2AR modulation of LPS-driven cell proliferation was also tested in primary cultures of mouse microglia. Results LPS induced time-dependent changes of the intra- and extracellular levels of BDNF and increased microglial proliferation. The maximal LPS-induced BDNF release was time-coincident with an LPS-induced increase of the A2AR density. Notably, removing endogenous extracellular adenosine or blocking A2AR prevented the LPS-mediated increase of both BDNF secretion and proliferation, as well as exogenous BDNF-induced proliferation. Conclusions We conclude that A2AR activation plays a mandatory role controlling the release of BDNF from activated microglia, as well as the autocrine/paracrine proliferative role of BDNF. PMID:23363775

  2. Bidirectional Microglia-Neuron Communication in the Healthy Brain

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    Ukpong B. Eyo

    2013-01-01

    Full Text Available Unlike other resident neural cells that are of neuroectodermal origin, microglia are resident neural cells of mesodermal origin. Traditionally recognized for their immune functions during disease, new roles are being attributed to these cells in the development and maintenance of the central nervous system (CNS including specific communication with neurons. In this review, we highlight some of the recent findings on the bidirectional interaction between neurons and microglia. We discuss these interactions along two lines. First, we review data that suggest that microglial activity is modulated by neuronal signals, focusing on evidence that (i neurons are capable of regulating microglial activation state and influence basal microglial activities; (ii classic neurotransmitters affect microglial behavior; (iii chemotactic signals attract microglia during acute neuronal injury. Next, we discuss some of the recent data on how microglia signal to neurons. Signaling mechanisms include (i direct physical contact of microglial processes with neuronal elements; (ii microglial regulation of neuronal synapse and circuit by fractalkine, complement, and DAP12 signaling. In addition, we discuss the use of microglial depletion strategies in studying the role of microglia in neuronal development and synaptic physiology. Deciphering the mechanisms of bidirectional microglial-neuronal communication provides novel insights in understanding microglial function in both the healthy and diseased brain.

  3. A starring role for microglia in brain sex differences.

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    Lenz, Kathryn M; McCarthy, Margaret M

    2015-06-01

    Microglia, the resident innate immune cells in the brain, have long been understood to be crucial to maintenance in the nervous system, by clearing debris, monitoring for infiltration of infectious agents, and mediating the brain's inflammatory and repair response to traumatic injury, stroke, or neurodegeneration. A wave of new research has shown that microglia are also active players in many basic processes in the healthy brain, including cell proliferation, synaptic connectivity, and physiology. Microglia, both in their capacity as phagocytic cells and via secretion of many neuroactive molecules, including cytokines and growth factors, play a central role in early brain development, including sexual differentiation of the brain. In this review, we present the vast roles microglia play in normal brain development and how perturbations in the normal neuroimmune environment during development may contribute to the etiology of brain-based disorders. There are notable differences between microglia and neuroimmune signaling in the male and female brain throughout the life span, and these differences may contribute to the vast differences in the incidence of neuropsychiatric and neurological disorders between males and females. © The Author(s) 2014.

  4. CD40 in Retinal Müller Cells Induces P2X7-Dependent Cytokine Expression in Macrophages/Microglia in Diabetic Mice and Development of Early Experimental Diabetic Retinopathy.

    Science.gov (United States)

    Portillo, Jose-Andres C; Lopez Corcino, Yalitza; Miao, Yanling; Tang, Jie; Sheibani, Nader; Kern, Timothy S; Dubyak, George R; Subauste, Carlos S

    2017-02-01

    Müller cells and macrophages/microglia are likely important for the development of diabetic retinopathy; however, the interplay between these cells in this disease is not well understood. An inflammatory process is linked to the onset of experimental diabetic retinopathy. CD40 deficiency impairs this process and prevents diabetic retinopathy. Using mice with CD40 expression restricted to Müller cells, we identified a mechanism by which Müller cells trigger proinflammatory cytokine expression in myeloid cells. During diabetes, mice with CD40 expressed in Müller cells upregulated retinal tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), intracellular adhesion molecule 1 (ICAM-1), and nitric oxide synthase (NOS2), developed leukostasis and capillary degeneration. However, CD40 did not cause TNF-α or IL-1β secretion in Müller cells. TNF-α was not detected in Müller cells from diabetic mice with CD40 + Müller cells. Rather, TNF-α was upregulated in macrophages/microglia. CD40 ligation in Müller cells triggered phospholipase C-dependent ATP release that caused P2X 7 -dependent production of TNF-α and IL-1β by macrophages. P2X 7 -/- mice and mice treated with a P2X 7 inhibitor were protected from diabetes-induced TNF-α, IL-1β, ICAM-1, and NOS2 upregulation. Our studies indicate that CD40 in Müller cells is sufficient to upregulate retinal inflammatory markers and appears to promote experimental diabetic retinopathy and that Müller cells orchestrate inflammatory responses in myeloid cells through a CD40-ATP-P2X 7 pathway. © 2017 by the American Diabetes Association.

  5. Unique inflammatory RNA profiles of microglia in Creutzfeldt-Jakob disease

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    Baker, Christopher A.; Manuelidis, Laura

    2003-01-01

    Previous studies in Creutzfeldt-Jakob disease (CJD) have shown that myeloid cells in the periphery as well as derivative microglial cells in the brain are infectious. Microglia can show an activated phenotype before prion protein (PrP) pathology is detectable in brain, and isolated infectious microglia contain very little PrP. To find whether a set of inflammatory genes are significantly induced or suppressed with infection, we analyzed RNA from isolated microglia with relevant cDNA arrays, and identified 30 transcripts not previously examined in any transmissible spongiform encephalopathy. This CJD expression profile contrasted with that of uninfected microglia exposed to prototypic inflammatory stimuli such as lipopolysaccharide and IFN-, as well as PrP amyloid. These findings underscore inflammatory pathways evoked by the infectious agent in brain. Transcript profiles unique for CJD microglia and other myeloid cells provide opportunities for more sensitive preclinical diagnoses of infectious and noninfectious neurodegenerative diseases.

  6. Microglia in Alzheimer's Disease: It's All About Context

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    Tara M. Weitz

    2012-01-01

    Full Text Available Neuroinflammation is now regarded as both an early event and prime mover in the pathobiology of Alzheimer disease (AD, a neurodegenerative disease that represents a growing public health threat. As the resident innate immune cells within the central nervous system, microglia are centrally positioned as key orchestrators of brain inflammation. It is now accepted that numerous forms of activated microglia exist. Furthermore, while some types of reactive microglia are detrimental, others can actually be beneficial. In the context of AD etiopathology, much debate surrounds whether these enigmatic cells play “good” or “bad” roles. In this article, we distill a complex clinical and experimental literature focused on the contribution of microglia to AD pathology and progression. A synthesis of the literature only seems possible when considering context– the conditions under which microglia encounter and mount immunological responses to AD pathology. In order to carry out these diverse contextual responses, a number of key receptors and signaling pathways are variously activated. It will be critically important for future studies to address molecular mediators that lead to beneficial microglial responses and therefore represent important therapeutic targets for AD.

  7. Histone deacetylase inhibitors suppress immune activation in primary mouse microglia

    NARCIS (Netherlands)

    Kannan, Vishnu; Brouwer, Nieske; Hanisch, Uwe-Karsten; Regen, Tommy; Eggen, Bart J. L.; Boddeke, Hendrikus W. G. M.

    Neuroinflammation is required for tissue clearance and repair after infections or insults. To prevent excessive damage, it is crucial to limit the extent of neuroinflammation and thereby the activation of its principal effector cell, microglia. The two main major innate immune cell types in the CNS

  8. Liposomal clodronate selectively eliminates microglia from primary astrocyte cultures

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    Kumamaru Hiromi

    2012-05-01

    Full Text Available Abstract Background There is increasing interest in astrocyte biology because astrocytes have been demonstrated to play prominent roles in physiological and pathological conditions of the central nervous system, including neuroinflammation. To understand astrocyte biology, primary astrocyte cultures are most commonly used because of the direct accessibility of astrocytes in this system. However, this advantage can be hindered by microglial contamination. Although several authors have warned regarding microglial contamination in this system, complete microglial elimination has never been achieved. Methods The number and proliferative potential of contaminating microglia in primary astrocyte cultures were quantitatively assessed by immunocytologic and flow cytometric analyses. To examine the utility of clodronate for microglial elimination, primary astrocyte cultures or MG-5 cells were exposed to liposomal or free clodronate, and then immunocytologic, flow cytometric, and gene expression analyses were performed. The gene expression profiles of microglia-eliminated and microglia-contaminated cultures were compared after interleukin-6 (IL-6 stimulation. Results The percentage of contaminating microglia exceeded 15% and continued to increase because of their high proliferative activity in conventional primary astrocyte cultures. These contaminating microglia were selectively eliminated low concentration of liposomal clodronate. Although primary microglia and MG-5 cells were killed by both liposomal and free clodronate, free clodronate significantly affected the viability of astrocytes. In contrast, liposomal clodronate selectively eliminated microglia without affecting the viability, proliferation or activation of astrocytes. The efficacy of liposomal clodronate was much higher than that of previously reported methods used for decreasing microglial contamination. Furthermore, we observed rapid tumor necrosis factor-α and IL-1b gene induction in

  9. High-fat diet-induced brain region-specific phenotypic spectrum of CNS resident microglia.

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    Baufeld, Caroline; Osterloh, Anja; Prokop, Stefan; Miller, Kelly R; Heppner, Frank L

    2016-09-01

    Diets high in fat (HFD) are known to cause an immune response in the periphery as well as the central nervous system. In peripheral adipose tissue, this immune response is primarily mediated by macrophages that are recruited to the tissue. Similarly, reactivity of microglia, the innate immune cells of the brain, has been shown to occur in the hypothalamus of mice fed a high-fat diet. To characterize the nature of the microglial response to diets high in fat in a temporal fashion, we studied the phenotypic spectrum of hypothalamic microglia of mice fed high-fat diet for 3 days and 8 weeks by assessing their tissue reaction and inflammatory signature. While we observed a significant increase in Iba1+ myeloid cells and a reaction of GFAP+ astrocytes in the hypothalamus after 8 weeks of HFD feeding, we found the hypothalamic myeloid cell reaction to be limited to endogenous microglia and not mediated by infiltrating myeloid cells. Moreover, obese humans were found to present with signs of hypothalamic gliosis and exacerbated microglia dystrophy, suggesting a targeted microglia response to diet in humans as well. Notably, the glial reaction occurring in the mouse hypothalamus was not accompanied by an increase in pro-inflammatory cytokines, but rather by an anti-inflammatory reaction. Gene expression analyses of isolated microglia not only confirmed this observation, but also revealed a downregulation of microglia genes important for sensing signals in the microenvironment. Finally, we demonstrate that long-term exposure of microglia to HFD in vivo does not impair the cell's ability to respond to additional stimuli, like lipopolysaccharide. Taken together, our findings support the notion that microglia react to diets high in fat in a region-specific manner in rodents as well as in humans; however, this response changes over time as it is not exclusively pro-inflammatory nor does exposure to HFD prime microglia in the hypothalamus.

  10. Microglia show altered morphology and reduced arborization in human brain during aging and Alzheimer's disease.

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    Davies, Danielle S; Ma, Jolande; Jegathees, Thuvarahan; Goldsbury, Claire

    2017-11-01

    Changes in microglia function are involved in Alzheimer's disease (AD) for which ageing is the major risk factor. We evaluated microglial cell process morphologies and their gray matter coverage (arborized area) during ageing and in the presence and absence of AD pathology in autopsied human neocortex. Microglial cell processes were reduced in length, showed less branching and reduced arborized area with aging (case range 52-98 years). This occurred during normal ageing and without microglia dystrophy or changes in cell density. There was a larger reduction in process length and arborized area in AD compared to aged-matched control microglia. In AD cases, on average, 49%-64% of microglia had discontinuous and/or punctate Iba1 labeled processes instead of continuous Iba1 distribution. Up to 16% of aged-matched control microglia displayed discontinuous or punctate features. There was no change in the density of microglial cell bodies in gray matter during ageing or AD. This demonstrates that human microglia show progressive cell process retraction without cell loss during ageing. Additional changes in microglia occur with AD including Iba1 protein puncta and discontinuity. We suggest that reduced microglial arborized area may be an aging-related correlate of AD in humans. These variations in microglial cells during ageing and in AD could reflect changes in neural-glial interactions which are emerging as key to mechanisms involved in ageing and neurodegenerative disease. © 2016 International Society of Neuropathology.

  11. Brain omega-3 polyunsaturated fatty acids modulate microglia cell number and morphology in response to intracerebroventricular amyloid-β 1-40 in mice.

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    Hopperton, Kathryn E; Trépanier, Marc-Olivier; Giuliano, Vanessa; Bazinet, Richard P

    2016-09-29

    Neuroinflammation is a proposed mechanism by which Alzheimer's disease (AD) pathology potentiates neuronal death and cognitive decline. Consumption of omega-3 polyunsaturated fatty acids (PUFA) is associated with a decreased risk of AD in human observational studies and exerts protective effects on cognition and pathology in animal models. These fatty acids and molecules derived from them are known to have anti-inflammatory and pro-resolving properties, presenting a potential mechanism for these protective effects. Here, we explore this mechanism using fat-1 transgenic mice and their wild type littermates weaned onto either a fish oil diet (high in n-3 PUFA) or a safflower oil diet (negligible n-3 PUFA). The fat-1 mouse carries a transgene that enables it to convert omega-6 to omega-3 PUFA. At 12 weeks of age, mice underwent intracerebroventricular (icv) infusion of amyloid-β 1-40. Brains were collected between 1 and 28 days post-icv, and hippocampal microglia, astrocytes, and degenerating neurons were quantified by immunohistochemistry with epifluorescence microscopy, while microglia morphology was assessed with confocal microscopy and skeleton analysis. Fat-1 mice fed with the safflower oil diet and wild type mice fed with the fish oil diet had higher brain DHA in comparison with the wild type mice fed with the safflower oil diet. Relative to the wild type mice fed with the safflower oil diet, fat-1 mice exhibited a lower peak in the number of labelled microglia, wild type mice fed with fish oil had fewer degenerating neurons, and both exhibited alterations in microglia morphology at 10 days post-surgery. There were no differences in astrocyte number at any time point and no differences in the time course of microglia or astrocyte activation following infusion of amyloid-β 1-40. Increasing brain DHA, through either dietary or transgenic means, decreases some elements of the inflammatory response to amyloid-β in a mouse model of AD. This supports the

  12. A quantitative spatiotemporal analysis of microglia morphology during ischemic stroke and reperfusion

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    Morrison Helena W

    2013-01-01

    Full Text Available Abstract Background Microglia cells continuously survey the healthy brain in a ramified morphology and, in response to injury, undergo progressive morphological and functional changes that encompass microglia activation. Although ideally positioned for immediate response to ischemic stroke (IS and reperfusion, their progressive morphological transformation into activated cells has not been quantified. In addition, it is not well understood if diverse microglia morphologies correlate to diverse microglia functions. As such, the dichotomous nature of these cells continues to confound our understanding of microglia-mediated injury after IS and reperfusion. The purpose of this study was to quantitatively characterize the spatiotemporal pattern of microglia morphology during the evolution of cerebral injury after IS and reperfusion. Methods Male C57Bl/6 mice were subjected to focal cerebral ischemia and periods of reperfusion (0, 8 and 24 h. The microglia process length/cell and number of endpoints/cell was quantified from immunofluorescent confocal images of brain regions using a skeleton analysis method developed for this study. Live cell morphology and process activity were measured from movies acquired in acute brain slices from GFP-CX3CR1 transgenic mice after IS and 24-h reperfusion. Regional CD11b and iNOS expressions were measured from confocal images and Western blot, respectively, to assess microglia proinflammatory function. Results Quantitative analysis reveals a significant spatiotemporal relationship between microglia morphology and evolving cerebral injury in the ipsilateral hemisphere after IS and reperfusion. Microglia were both hyper- and de-ramified in striatal and cortical brain regions (respectively after 60 min of focal cerebral ischemia. However, a de-ramified morphology was prominent when ischemia was coupled to reperfusion. Live microglia were de-ramified, and, in addition, process activity was severely blunted proximal to

  13. Regulation of vacuolar H{sup +}-ATPase in microglia by RANKL

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Eric M.; Ricofort, Ryan D.; Zuo, Jian [Department of Orthodontics, University of Florida College of Dentistry, Gainesville, FL 32610 (United States); Ochotny, Noelle [Department of Pharmacology, University of Toronto, Toronto, Ont., Canada M5G 1G6 (Canada); Manolson, Morris F. [Faculty of Dentistry, University of Toronto, Toronto, Ont., Canada M5G 1G6 (Canada); Holliday, L. Shannon, E-mail: sholliday@dental.ufl.edu [Department of Orthodontics, University of Florida College of Dentistry, Gainesville, FL 32610 (United States); Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL 32610 (United States)

    2009-11-06

    Vacuolar H{sup +}-ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPases play specialized roles in certain cell types, a capacity that is linked to cell type selective expression of isoforms of some of the subunits. We detected low levels of the a3 isoform of the a-subunit in mouse brain extracts. Examination of various brain-derived cell types by immunoblotting showed a3 was expressed in the N9 microglia cell line and in primary microglia, but not in other cell types. The expression of a3 in osteoclasts requires stimulation by Receptor Activator of Nuclear Factor {kappa}B-ligand (RANKL). We found that Receptor Activator of Nuclear Factor {kappa}B (RANK) was expressed by microglia. Stimulation of microglia with RANKL triggered increased expression of a3. V-ATPases in microglia were shown to bind microfilaments, and stimulation with RANKL increased the proportion of V-ATPase associated with the detergent-insoluble cytoskeletal fraction and with actin. In summary, microglia express the a3-subunit of V-ATPase. The expression of a3 and the interaction between V-ATPases and microfilaments was modulated by RANKL. These data suggest a novel molecular pathway for regulating microglia.

  14. The Indispensable Roles of Microglia and Astrocytes during Brain Development

    NARCIS (Netherlands)

    Reemst, K.; Noctor, S.C.; Lucassen, P.J.; Hol, E.M.

    2016-01-01

    Glia are essential for brain functioning during development and in the adult brain. Here, we discuss the various roles of both microglia and astrocytes, and their interactions during brain development. Although both cells are fundamentally different in origin and function, they often affect the same

  15. Love and death: microglia, NLRP3 and the Alzheimer's brain.

    Science.gov (United States)

    Goldmann, Tobias; Tay, Tuan Leng; Prinz, Marco

    2013-05-01

    Microglia were previously attributed to be vital brain guardians for neuronal survival and synaptic pruning during development as well as for the brain's fight against environmental pathogens. A new report in Nature by the Heneka, Latz and Golenbock groups, however, sheds new light on these distinct myeloid cells by revealing their deadly nature for mature neurons during neurodegeneration.

  16. The indispensable roles of microglia and astrocytes during brain development

    NARCIS (Netherlands)

    Reemst, Kitty; Noctor, Stephen C.; Lucassen, Paul J.; Hol, Elly M.

    2016-01-01

    Glia are essential for brain functioning during development and in the adult brain. Here, we discuss the various roles of both microglia and astrocytes, and their interactions during brain development. Although both cells are fundamentally different in origin and function, they often affect the same

  17. A Distinct Population of Microglia Supports Adult Neurogenesis in the Subventricular Zone

    DEFF Research Database (Denmark)

    Ribeiro Xavier, Anna L.; Kress, Benjamin T.; Goldman, Steven A.

    2015-01-01

    found that microglia residing in the SVZ and adjacent rostral migratory stream (RMS) comprise a morphologically and antigenically distinct phenotype of immune effectors. Whereas exhibiting characteristics of alternatively activated microglia, the SVZ/RMS microglia were clearly distinguished by their low...... STATEMENT: Microglial cells are a specialized population of macrophages in the CNS, playing key roles as immune mediators. As integral components in the CNS, the microglia stand out for using the same mechanisms, phagocytosis and cytochemokine release, to promote homeostasis, synaptic pruning, and neural...... toward olfactory bulb layers. In addition to other unique populations residing in the SVZ niche, microglia display distinct morphofunctional properties that boost neuronal progenitor survival and migration in the mammalian brain....

  18. Microglia Gone Rogue: Impacts on Psychiatric Disorders across the Lifespan

    Directory of Open Access Journals (Sweden)

    Tuan Leng Tay

    2018-01-01

    Full Text Available Microglia are the predominant immune response cells and professional phagocytes of the central nervous system (CNS that have been shown to be important for brain development and homeostasis. These cells present a broad spectrum of phenotypes across stages of the lifespan and especially in CNS diseases. Their prevalence in all neurological pathologies makes it pertinent to reexamine their distinct roles during steady-state and disease conditions. A major question in the field is determining whether the clustering and phenotypical transformation of microglial cells are leading causes of pathogenesis, or potentially neuroprotective responses to the onset of disease. The recent explosive growth in our understanding of the origin and homeostasis of microglia, uncovering their roles in shaping of the neural circuitry and synaptic plasticity, allows us to discuss their emerging functions in the contexts of cognitive control and psychiatric disorders. The distinct mesodermal origin and genetic signature of microglia in contrast to other neuroglial cells also make them an interesting target for the development of therapeutics. Here, we review the physiological roles of microglia, their contribution to the effects of environmental risk factors (e.g., maternal infection, early-life stress, dietary imbalance, and their impact on psychiatric disorders initiated during development (e.g., Nasu-Hakola disease (NHD, hereditary diffuse leukoencephaly with spheroids, Rett syndrome, autism spectrum disorders (ASDs, and obsessive-compulsive disorder (OCD or adulthood (e.g., alcohol and drug abuse, major depressive disorder (MDD, bipolar disorder (BD, schizophrenia, eating disorders and sleep disorders. Furthermore, we discuss the changes in microglial functions in the context of cognitive aging, and review their implication in neurodegenerative diseases of the aged adult (e.g., Alzheimer’s and Parkinson’s. Taking into account the recent identification of

  19. Microglia Gone Rogue: Impacts on Psychiatric Disorders across the Lifespan.

    Science.gov (United States)

    Tay, Tuan Leng; Béchade, Catherine; D'Andrea, Ivana; St-Pierre, Marie-Kim; Henry, Mathilde S; Roumier, Anne; Tremblay, Marie-Eve

    2017-01-01

    Microglia are the predominant immune response cells and professional phagocytes of the central nervous system (CNS) that have been shown to be important for brain development and homeostasis. These cells present a broad spectrum of phenotypes across stages of the lifespan and especially in CNS diseases. Their prevalence in all neurological pathologies makes it pertinent to reexamine their distinct roles during steady-state and disease conditions. A major question in the field is determining whether the clustering and phenotypical transformation of microglial cells are leading causes of pathogenesis, or potentially neuroprotective responses to the onset of disease. The recent explosive growth in our understanding of the origin and homeostasis of microglia, uncovering their roles in shaping of the neural circuitry and synaptic plasticity, allows us to discuss their emerging functions in the contexts of cognitive control and psychiatric disorders. The distinct mesodermal origin and genetic signature of microglia in contrast to other neuroglial cells also make them an interesting target for the development of therapeutics. Here, we review the physiological roles of microglia, their contribution to the effects of environmental risk factors (e.g., maternal infection, early-life stress, dietary imbalance), and their impact on psychiatric disorders initiated during development (e.g., Nasu-Hakola disease (NHD), hereditary diffuse leukoencephaly with spheroids, Rett syndrome, autism spectrum disorders (ASDs), and obsessive-compulsive disorder (OCD)) or adulthood (e.g., alcohol and drug abuse, major depressive disorder (MDD), bipolar disorder (BD), schizophrenia, eating disorders and sleep disorders). Furthermore, we discuss the changes in microglial functions in the context of cognitive aging, and review their implication in neurodegenerative diseases of the aged adult (e.g., Alzheimer's and Parkinson's). Taking into account the recent identification of microglia

  20. CpG-ODNs induces up-regulated expression of chemokine CCL9 in mouse macrophages and microglia

    Digital Repository Service at National Institute of Oceanography (India)

    Ravindran, C.; Cheng, Y.-C.; Liang, S.-M.

    G-ODNs on macrophage/microglial cells are investigated. CpG-ODNs enhanced the expression of TLR9 mRNA of RAW264.7 macrophage and BV2 microglia cells time dependently. The expression of CCL9 of macrophages/microglia showed different responsiveness upon stimulation...

  1. Benfotiamine attenuates inflammatory response in LPS stimulated BV-2 microglia.

    Science.gov (United States)

    Bozic, Iva; Savic, Danijela; Laketa, Danijela; Bjelobaba, Ivana; Milenkovic, Ivan; Pekovic, Sanja; Nedeljkovic, Nadezda; Lavrnja, Irena

    2015-01-01

    Microglial cells are resident immune cells of the central nervous system (CNS), recognized as key elements in the regulation of neural homeostasis and the response to injury and repair. As excessive activation of microglia may lead to neurodegeneration, therapeutic strategies targeting its inhibition were shown to improve treatment of most neurodegenerative diseases. Benfotiamine is a synthetic vitamin B1 (thiamine) derivate exerting potentially anti-inflammatory effects. Despite the encouraging results regarding benfotiamine potential to alleviate diabetic microangiopathy, neuropathy and other oxidative stress-induced pathological conditions, its activities and cellular mechanisms during microglial activation have yet to be elucidated. In the present study, the anti-inflammatory effects of benfotiamine were investigated in lipopolysaccharide (LPS)-stimulated murine BV-2 microglia. We determined that benfotiamine remodels activated microglia to acquire the shape that is characteristic of non-stimulated BV-2 cells. In addition, benfotiamine significantly decreased production of pro-inflammatory mediators such as inducible form of nitric oxide synthase (iNOS) and NO; cyclooxygenase-2 (COX-2), heat-shock protein 70 (Hsp70), tumor necrosis factor alpha α (TNF-α), interleukin-6 (IL-6), whereas it increased anti-inflammatory interleukin-10 (IL-10) production in LPS stimulated BV-2 microglia. Moreover, benfotiamine suppressed the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK) and protein kinase B Akt/PKB. Treatment with specific inhibitors revealed that benfotiamine-mediated suppression of NO production was via JNK1/2 and Akt pathway, while the cytokine suppression includes ERK1/2, JNK1/2 and Akt pathways. Finally, the potentially protective effect is mediated by the suppression of translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the nucleus. Therefore, benfotiamine may

  2. Activated microglia in the spinal cord underlies diabetic neuropathic pain.

    Science.gov (United States)

    Wang, Dongmei; Couture, Réjean; Hong, Yanguo

    2014-04-05

    Diabetes mellitus is an increasingly common chronic medical condition. Approximately 30% of diabetic patients develop neuropathic pain, manifested as spontaneous pain, hyperalgesia and allodynia. Hyperglycemia induces metabolic changes in peripheral tissues and enhances oxidative stress in nerve fibers. The damages and subsequent reactive inflammation affect structural properties of Schwann cells and axons leading to the release of neuropoietic mediators, such as pro-inflammatory cytokines and pro-nociceptive mediators. Therefore, diabetic neuropathic pain (DNP) shares some histological features and underlying mechanisms with traumatic neuropathy. DNP displays, however, other distinct features; for instance, sensory input to the spinal cord decreases rather than increasing in diabetic patients. Consequently, development of central sensitization in DNP involves mechanisms that are distinct from traumatic neuropathic pain. In DNP, the contribution of spinal cord microglia activation to central sensitization and pain processes is emerging as a new concept. Besides inflammation in the periphery, hyperglycemia and the resulting production of reactive oxygen species affect the local microenvironment in the spinal cord. All these alterations could trigger resting and sessile microglia to the activated phenotype. In turn, microglia synthesize and release pro-inflammatory cytokines and neuroactive molecules capable of inducing hyperactivity of spinal nociceptive neurons. Hence, it is imperative to elucidate glial mechanisms underlying DNP for the development of effective therapeutic agents. The present review highlights the recent developments regarding the contribution of spinal microglia as compelling target for the treatment of DNP. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Microglia are essential to masculinization of brain and behavior

    Science.gov (United States)

    Lenz, Kathryn M.; Nugent, Bridget M.; Haliyur, Rachana; McCarthy, Margaret M.

    2013-01-01

    Brain sexual differentiation in rodents results from the perinatal testicular androgen surge. In the preoptic area (POA), estradiol aromatized from testosterone upregulates the production of the proinflammatory molecule, prostaglandin E2 (PGE2) to produce sex-specific brain development. PGE2 produces a two-fold greater density of dendritic spines in males than in females and masculinizes adult copulatory behavior. One neonatal dose of PGE2 masculinizes the POA and behavior, and simultaneous treatment with an inhibitor of additional prostaglandin synthesis prevents this masculinization, indicating a positive feed-forward process that leads to sustained increases in PGE2. The mechanisms underlying this feed-forward process were unknown. Microglia, the primary immunocompetent cells in the brain, are active neonatally, contribute to normal brain development, and both produce and respond to prostaglandins. We investigated whether there are sex differences in microglia in the POA and whether they influence developmental masculinization. Neonatal males had twice as many ameboid microglia as females and a more activated morphological profile, and both estradiol and PGE2 masculinized microglial number and morphology in females. Microglial inhibition during the critical period for sexual differentiation prevented sex differences in microglia, estradiol-induced masculinization of dendritic spine density, and adult copulatory behavior. Microglial inhibition also prevented the estradiol-induced upregulation of PGE2, indicating that microglia are essential to the feed-forward process through which estradiol upregulates prostaglandin production. These studies demonstrate that immune cells in the brain interact with the nervous and endocrine systems during development, and are crucial for sexual differentiation of brain and behavior. PMID:23407936

  4. Tubulin cofactor B regulates microtubule densities during microglia transition to the reactive states

    International Nuclear Information System (INIS)

    Fanarraga, M.L.; Villegas, J.C.; Carranza, G.; Castano, R.; Zabala, J.C.

    2009-01-01

    Microglia are highly dynamic cells of the CNS that continuously survey the welfare of the neural parenchyma and play key roles modulating neurogenesis and neuronal cell death. In response to injury or pathogen invasion parenchymal microglia transforms into a more active cell that proliferates, migrates and behaves as a macrophage. The acquisition of these extra skills implicates enormous modifications of the microtubule and actin cytoskeletons. Here we show that tubulin cofactor B (TBCB), which has been found to contribute to various aspects of microtubule dynamics in vivo, is also implicated in microglial cytoskeletal changes. We find that TBCB is upregulated in post-lesion reactive parenchymal microglia/macrophages, in interferon treated BV-2 microglial cells, and in neonate amoeboid microglia where the microtubule densities are remarkably low. Our data demonstrate that upon TBCB downregulation both, after microglia differentiation to the ramified phenotype in vivo and in vitro, or after TBCB gene silencing, microtubule densities are restored in these cells. Taken together these observations support the view that TBCB functions as a microtubule density regulator in microglia during activation, and provide an insight into the understanding of the complex mechanisms controlling microtubule reorganization during microglial transition between the amoeboid, ramified, and reactive phenotypes

  5. Dystrophic microglia in the aging human brain.

    Science.gov (United States)

    Streit, Wolfgang J; Sammons, Nicole W; Kuhns, Amanda J; Sparks, D Larry

    2004-01-15

    We have studied microglial morphology in the human cerebral cortex of two nondemented subjects using high-resolution LN-3 immunohistochemistry. Several abnormalities in microglial cytoplasmic structure, including deramification, spheroid formation, gnarling, and fragmentation of processes, were identified. These changes were determined to be different from the morphological changes that occur during microglial activation and they were designated collectively as microglial dystrophy. Quantitative evaluation of dystrophic changes in microglia revealed that these were much more prevalent in the older subject (68-year-old) than in the younger one (38-year-old). Thus, we conclude that microglial dystrophy is a sign of microglial cell senescence. We hypothesize that microglial senescence could be important for understanding age-related declines in cognitive function. Copyright 2003 Wiley-Liss, Inc.

  6. High Morphologic Plasticity of Microglia/Macrophages Following Experimental Intracerebral Hemorrhage in Rats

    Directory of Open Access Journals (Sweden)

    Shu-Sheng Yang

    2016-07-01

    Full Text Available As current efforts have limited effects on the clinical outcome of intracerebral hemorrhage (ICH, the mechanisms including microglia/macrophages that involved inflammation need further investigation. Here, 0.4 units of collagenase VII were injected into the left caudate putamen (CPu to duplicate ICH rat models. In the brains of ICH rats, microglia/macrophages, the nearest cells to the hemorrhagic center, were observed as ameboid and Prussian-blue positive. Furthermore, the ameboid microglia/macrophages were differentiation (CD 68 and interleukin-1β (IL-1β positive, and neither CD206 nor chitinase3-like 3 (Ym1 positive, suggesting their strong abilities of phagocytosis and secretion of IL-1β. According to the distance to the hemorrhagic center, we selected four areas—I, II, III, and IV—to analyze the morphology of microglia/macrophages. The processes decreased successively from region I to region IV. Microglia/macrophages in region IV had no processes. The processes in region I were radially distributed, however, they showed obvious directivity towards the hemorrhagic center in regions II and III. Region III had the largest density of compactly arrayed microglia/macrophages. All these in vivo results present the high morphologic plasticity of microglia/macrophages and their functions in the pathogenesis of ICHs.

  7. The role of glucocorticoid, interleukin-1β, and antioxidants in prenatal stress effects on embryonic microglia.

    Science.gov (United States)

    Bittle, Jada; Stevens, Hanna E

    2018-02-16

    Maternal stress during pregnancy is associated with an increased risk of psychopathology in offspring. Resident immune cells of the brain, microglia, may be mediators of prenatal stress and altered neurodevelopment. Here, we demonstrate that neither the exogenous pro-inflammatory cytokine, interleukin-1β (IL-1β), nor the glucocorticoid hormone, corticosterone, recapitulated the full effects of prenatal stress on the morphology of microglial cells in the cortical plate of embryonic mice; IL-1β effects showed greater similarity to prenatal stress effects on microglia. Unexpectedly, oil vehicle alone, which has antioxidant properties, moderated the effects of prenatal stress on microglia. Microglia changes with prenatal stress were also sensitive to the antioxidant, N-acetylcysteine, suggesting redox dysregulation as a mechanism of prenatal stress.

  8. Surveillance, Phagocytosis, and Inflammation: How Never-Resting Microglia Influence Adult Hippocampal Neurogenesis

    Directory of Open Access Journals (Sweden)

    Amanda Sierra

    2014-01-01

    Full Text Available Microglia cells are the major orchestrator of the brain inflammatory response. As such, they are traditionally studied in various contexts of trauma, injury, and disease, where they are well-known for regulating a wide range of physiological processes by their release of proinflammatory cytokines, reactive oxygen species, and trophic factors, among other crucial mediators. In the last few years, however, this classical view of microglia was challenged by a series of discoveries showing their active and positive contribution to normal brain functions. In light of these discoveries, surveillant microglia are now emerging as an important effector of cellular plasticity in the healthy brain, alongside astrocytes and other types of inflammatory cells. Here, we will review the roles of microglia in adult hippocampal neurogenesis and their regulation by inflammation during chronic stress, aging, and neurodegenerative diseases, with a particular emphasis on their underlying molecular mechanisms and their functional consequences for learning and memory.

  9. Innate immune functions of microglia isolated from human glioma patients

    Directory of Open Access Journals (Sweden)

    Grimm Elizabeth

    2006-03-01

    Full Text Available Abstract Background Innate immunity is considered the first line of host defense and microglia presumably play a critical role in mediating potent innate immune responses to traumatic and infectious challenges in the human brain. Fundamental impairments of the adaptive immune system in glioma patients have been investigated; however, it is unknown whether microglia are capable of innate immunity and subsequent adaptive anti-tumor immune responses within the immunosuppressive tumor micro-environment of human glioma patients. We therefore undertook a novel characterization of the innate immune phenotype and function of freshly isolated human glioma-infiltrating microglia (GIM. Methods GIM were isolated by sequential Percoll purification from patient tumors immediately after surgical resection. Flow cytometry, phagocytosis and tumor cytotoxicity assays were used to analyze the phenotype and function of these cells. Results GIM expressed significant levels of Toll-like receptors (TLRs, however they do not secrete any of the cytokines (IL-1β, IL-6, TNF-α critical in developing effective innate immune responses. Similar to innate macrophage functions, GIM can mediate phagocytosis and non-MHC restricted cytotoxicity. However, they were statistically less able to mediate tumor cytotoxicity compared to microglia isolated from normal brain. In addition, the expression of Fas ligand (FasL was low to absent, indicating that apoptosis of the incoming lymphocyte population may not be a predominant mode of immunosuppression by microglia. Conclusion We show for the first time that despite the immunosuppressive environment of human gliomas, GIM are capable of innate immune responses such as phagocytosis, cytotoxicity and TLR expression but yet are not competent in secreting key cytokines. Further understanding of these innate immune functions could play a critical role in understanding and developing effective immunotherapies to malignant human gliomas.

  10. Microglia energy metabolism in metabolic disorder

    NARCIS (Netherlands)

    Kalsbeek, Martin J. T.; Mulder, Laurie; Yi, Chun-Xia

    2016-01-01

    Microglia are the resident macrophages of the CNS, and are in charge of maintaining a healthy microenvironment to ensure neuronal survival. Microglia carry out a non-stop patrol of the CNS, make contact with neurons and look for abnormalities, all of which requires a vast amount of energy. This

  11. Selective Estrogen Receptor Modulators regulate reactive microglia after penetrating brain injury

    Directory of Open Access Journals (Sweden)

    George E. Barreto

    2014-06-01

    Full Text Available Following brain injury, microglia assume a reactive-like state and secrete pro-inflammatory molecules that can potentiate damage. A therapeutic strategy that may limit microgliosis is of potential interest. In this context, selective estrogen receptor modulators, such as raloxifene and tamoxifen, are known to reduce microglia activation induced by neuroinflammatory stimuli in young animals. In the present study, we have assessed whether raloxifene and tamoxifen are able to affect microglia activation after brain injury in young and aged animals in time points relevant to clinics, which is hours after brain trauma. Volume fraction of MHC-II+ microglia was estimated according to the point-counting method of Weibel within a distance of 350 μm from the lateral border of the wound, and cellular morphology was measured by fractal analysis. Two groups of animals were studied: 1 young rats, ovariectomized at 2 months of age; and 2 aged rats, ovariectomized at 18 months of age. Fifteen days after ovariectomy animals received a stab wound brain injury and the treatment with estrogenic compounds. Our findings indicate that raloxifene and tamoxifen reduced microglia activation in both young and aged animals. Although the volume fraction of reactive microglia was found lower in aged animals, this was accompanied by important changes in cell morphology, where aged microglia assume a bushier and hyperplasic aspect when compared to young microglia. These data suggest that early regulation of microglia activation provides a mechanism by which SERMs may exert a neuroprotective effect in the setting of a brain trauma.

  12. Microglia in diffuse plaques in hereditary cerebral hemorrhage with amyloidosis (Dutch). An immunohistochemical study.

    Science.gov (United States)

    Maat-Schieman, M L; Rozemuller, A J; van Duinen, S G; Haan, J; Eikelenboom, P; Roos, R A

    1994-09-01

    In hereditary cerebral hemorrhage with amyloidosis (Dutch) (HCHWA-D) beta/A4 amyloid deposition is found in meningocortical blood vessels and in diffuse plaques in the cerebral cortex. Diffuse plaques putatively represent early stages in the formation of senile plaques. Microglia are intimately associated with congophilic plaques in Alzheimer's disease (AD), but microglial involvement in diffuse plaque formation is controversial. Therefore, we studied the relationship between microglia and diffuse plaques in the cerebral cortex of four patients with HCHWA-D using a panel of macrophage/microglia markers (mAbs LCA, LeuM5, LeuM3, LN3, KP1, OKIa, CLB54, Mac1, Ki-M6, AMC30 and the lectin RCA-1). Eight AD patients, one demented Down's syndrome (DS) patient and four non-demented controls were included for comparison. In controls and HCHWA-D patients ramified or "resting" microglia formed a reticular array in cortical gray and subcortical white matter. Microglial cells in or near HCHWA-D diffuse plaques retained their normal regular spacing and ramified morphology. In AD/DS gray matter more microglial cells were stained than in controls and HCHWA-D patients. Intensely immunoreactive microglia with enlarged cell bodies and short, thick processes clustered in congophilic plaques. In contrast to the resting microglia, these "activated microglia" strongly expressed class II major histocompatibility complex antigen, HLA-DR, and were AMC30-immunoreactive. These findings support the view that microglia play a role in the formation of congophilic plaques but do not initiate diffuse plaque formation. Another finding in this study is the presence of strong monocyte/macrophage marker immunoreactivity in the wall of cortical congophilic blood vessels in HCHWA-D.

  13. Isolation of primary microglia from the human post-mortem brain: effects of ante- and post-mortem variables.

    Science.gov (United States)

    Mizee, Mark R; Miedema, Suzanne S M; van der Poel, Marlijn; Adelia; Schuurman, Karianne G; van Strien, Miriam E; Melief, Jeroen; Smolders, Joost; Hendrickx, Debbie A; Heutinck, Kirstin M; Hamann, Jörg; Huitinga, Inge

    2017-02-17

    Microglia are key players in the central nervous system in health and disease. Much pioneering research on microglia function has been carried out in vivo with the use of genetic animal models. However, to fully understand the role of microglia in neurological and psychiatric disorders, it is crucial to study primary human microglia from brain donors. We have developed a rapid procedure for the isolation of pure human microglia from autopsy tissue using density gradient centrifugation followed by CD11b-specific cell selection. The protocol can be completed in 4 h, with an average yield of 450,000 and 145,000 viable cells per gram of white and grey matter tissue respectively. This method allows for the immediate phenotyping of microglia in relation to brain donor clinical variables, and shows the microglia population to be distinguishable from autologous choroid plexus macrophages. This protocol has been applied to samples from over 100 brain donors from the Netherlands Brain Bank, providing a robust dataset to analyze the effects of age, post-mortem delay, brain acidity, and neurological diagnosis on microglia yield and phenotype. Our data show that cerebrospinal fluid pH is positively correlated to microglial cell yield, but donor age and post-mortem delay do not negatively affect viable microglia yield. Analysis of CD45 and CD11b expression showed that changes in microglia phenotype can be attributed to a neurological diagnosis, and are not influenced by variation in ante- and post-mortem parameters. Cryogenic storage of primary microglia was shown to be possible, albeit with variable levels of recovery and effects on phenotype and RNA quality. Microglial gene expression substantially changed due to culture, including the loss of the microglia-specific markers, showing the importance of immediate microglia phenotyping. We conclude that primary microglia can be isolated effectively and rapidly from human post-mortem brain tissue, allowing for the study of the

  14. In vitro modeling of HIV proviral activity in microglia.

    Science.gov (United States)

    Campbell, Lee A; Richie, Christopher T; Zhang, Yajun; Heathward, Emily J; Coke, Lamarque M; Park, Emily Y; Harvey, Brandon K

    2017-12-01

    Microglia, the resident macrophages of the brain, play a key role in the pathogenesis of HIV-associated neurocognitive disorders (HAND) due to their productive infection by HIV. This results in the release of neurotoxic viral proteins and pro-inflammatory compounds which negatively affect the functionality of surrounding neurons. Because models of HIV infection within the brain are limited, we aimed to create a novel microglia cell line with an integrated HIV provirus capable of recreating several hallmarks of HIV infection. We utilized clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing technology and integrated a modified HIV provirus into CHME-5 immortalized microglia to create HIV-NanoLuc CHME-5. In the modified provirus, the Gag-Pol region is replaced with the coding region for NanoLuciferase (NanoLuc), which allows for the rapid assay of HIV long terminal repeat activity using a luminescent substrate, while still containing the necessary genetic material to produce established neurotoxic viral proteins (e.g. tat, nef, gp120). We confirmed that HIV-NanoLuc CHME-5 microglia express NanoLuc, along with the HIV viral protein Nef. We subsequently exposed these cells to a battery of experiments to modulate the activity of the provirus. Proviral activity was enhanced by treating the cells with pro-inflammatory factors lipopolysaccharide (LPS) and tumor necrosis factor alpha and by overexpressing the viral regulatory protein Tat. Conversely, genetic modification of the toll-like receptor-4 gene by CRISPR/Cas9 reduced LPS-mediated proviral activation, and pharmacological application of NF-κB inhibitor sulfasalazine similarly diminished proviral activity. Overall, these data suggest that HIV-NanoLuc CHME-5 may be a useful tool in the study of HIV-mediated neuropathology and proviral regulation. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  15. Glucose pathways adaptation supports acquisition of activated microglia phenotype.

    Science.gov (United States)

    Gimeno-Bayón, J; López-López, A; Rodríguez, M J; Mahy, N

    2014-06-01

    With its capacity to survey the environment and phagocyte debris, microglia assume a diversity of phenotypes to respond specifically through neurotrophic and toxic effects. Although these roles are well accepted, the underlying energetic mechanisms associated with microglial activation remain largely unclear. This study investigates microglia metabolic adaptation to ATP, NADPH, H(+) , and reactive oxygen species production. To this end, in vitro studies were performed with BV-2 cells before and after activation with lipopolysaccharide + interferon-γ. Nitric oxide (NO) was measured as a marker of cell activation. Our results show that microglial activation triggers a metabolic reprogramming based on an increased glucose uptake and a strengthening of anaerobic glycolysis, as well as of the pentose pathway oxidative branch, while retaining the mitochondrial activity. Based on this energy commitment, microglial defense capacity increases rapidly as well as ribose-5-phosphate and nucleic acid formation for gene transcription, essential to ensure the newly acquired functions demanded by central nervous system signaling. We also review the role of NO in this microglial energy commitment that positions cytotoxic microglia within the energetics of the astrocyte-neuron lactate shuttle. Copyright © 2014 Wiley Periodicals, Inc.

  16. Learned helplessness activates hippocampal microglia in rats: A potential target for the antidepressant imipramine.

    Science.gov (United States)

    Iwata, Masaaki; Ishida, Hisahito; Kaneko, Koichi; Shirayama, Yukihiko

    An accumulating body of evidence has demonstrated that inflammation is associated with the pathology of depression. We recently found that psychological stress induces inflammation in the hippocampus of the rat brain through the inflammasome, a component of the innate immune system. Microglia, the resident macrophages in the brain, play a central role in the innate immune system and express inflammasomes; thus, we hypothesized that hippocampal microglia would be key mediators in the development of depression via stress-induced inflammation. To test this hypothesis and to determine how antidepressants modulate microglial function, we used immunohistochemistry to examine the morphological changes that occur in the hippocampal microglia of rats exposed to the learned helplessness (LH) paradigm. We noted significantly increased numbers of activated microglia in the granule cell layer, hilus, CA1, and CA3 regions of the hippocampi of LH rats. Conversely, administering imipramine to LH rats for 7days produced a significant decrease in the number of activated microglia in the hilus, but not in the other examined regions. Nonetheless, there were no significant differences in the combined number of activated and non-activated microglia either in LH or LH+imipramine rats relative to control rats. In addition, treating the naïve rats with imipramine or fluvoxamine produced no discernible microglial changes. These data suggest that stress activates hippocampal microglia, while certain antidepressants decrease the number of activated microglia in the hilus, but not in other hippocampal regions. Therefore, the hilus represents a candidate target region for the antidepressant imipramine. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Priming of microglia in a DNA-repair deficient model of accelerated aging.

    Science.gov (United States)

    Raj, Divya D A; Jaarsma, Dick; Holtman, Inge R; Olah, Marta; Ferreira, Filipa M; Schaafsma, Wandert; Brouwer, Nieske; Meijer, Michel M; de Waard, Monique C; van der Pluijm, Ingrid; Brandt, Renata; Kreft, Karim L; Laman, Jon D; de Haan, Gerald; Biber, Knut P H; Hoeijmakers, Jan H J; Eggen, Bart J L; Boddeke, Hendrikus W G M

    2014-09-01

    Aging is associated with reduced function, degenerative changes, and increased neuroinflammation of the central nervous system (CNS). Increasing evidence suggests that changes in microglia cells contribute to the age-related deterioration of the CNS. The most prominent age-related change of microglia is enhanced sensitivity to inflammatory stimuli, referred to as priming. It is unclear if priming is due to intrinsic microglia ageing or induced by the ageing neural environment. We have studied this in Ercc1 mutant mice, a DNA repair-deficient mouse model that displays features of accelerated aging in multiple tissues including the CNS. In Ercc1 mutant mice, microglia showed hallmark features of priming such as an exaggerated response to peripheral lipopolysaccharide exposure in terms of cytokine expression and phagocytosis. Specific targeting of the Ercc1 deletion to forebrain neurons resulted in a progressive priming response in microglia exemplified by phenotypic alterations. Summarizing, these data show that neuronal genotoxic stress is sufficient to switch microglia from a resting to a primed state. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Molecular Targets for PET Imaging of Activated Microglia: The Current Situation and Future Expectations.

    Science.gov (United States)

    Tronel, Claire; Largeau, Bérenger; Santiago Ribeiro, Maria Joao; Guilloteau, Denis; Dupont, Anne-Claire; Arlicot, Nicolas

    2017-04-11

    Microglia, as cellular mediators of neuroinflammation, are implicated in the pathogenesis of a wide range of neurodegenerative diseases. Positron emission tomography (PET) imaging of microglia has matured over the last 20 years, through the development of radiopharmaceuticals targeting several molecular biomarkers of microglial activation and, among these, mainly the translocator protein-18 kDa (TSPO). Nevertheless, current limitations of TSPO as a PET microglial biomarker exist, such as low brain density, even in a neurodegenerative setting, expression by other cells than the microglia (astrocytes, peripheral macrophages in the case of blood brain barrier breakdown), genetic polymorphism, inducing a variation for most of TSPO PET radiopharmaceuticals' binding affinity, or similar expression in activated microglia regardless of its polarization (pro- or anti-inflammatory state), and these limitations narrow its potential interest. We overview alternative molecular targets, for which dedicated radiopharmaceuticals have been proposed, including receptors (purinergic receptors P2X7, cannabinoid receptors, α7 and α4β2 nicotinic acetylcholine receptors, adenosine 2A receptor, folate receptor β) and enzymes (cyclooxygenase, nitric oxide synthase, matrix metalloproteinase, β-glucuronidase, and enzymes of the kynurenine pathway), with a particular focus on their respective contribution for the understanding of microglial involvement in neurodegenerative diseases. We discuss opportunities for these potential molecular targets for PET imaging regarding their selectivity for microglia expression and polarization, in relation to the mechanisms by which microglia actively participate in both toxic and neuroprotective actions in brain diseases, and then take into account current clinicians' expectations.

  19. The effects of electromagnetic irradiation on activation of microglia and JAKs in rat hippocampus

    International Nuclear Information System (INIS)

    Chen Chunhai; Yang Xuesen; Hao Yutong; Zhang Guangbin; Yu Zhengping

    2008-01-01

    Objective: To determine the activation of microglia and the phosphorylation of Jaks, the upstream factors of JAK/STAT(janus activated kinase/signal transducers and activators of transcription) signaling pathway, after electromagnetic irradiation. Methods: Rats were irradiated by 90 mW/cm 2 EMF for 20 min. The phosphorylation of Jaks was determined by western blot at different time after electromagnetic irradiation. The activation of microglia was determined by immuno- chemistry. Results: GSA-IB4 was upregulated in microglia, which indicated microglia was activated after electromagnetic irradiation. The phosphorylation of Jak1, Jak2 and Jak3 in rat hippocampus was upregulated after electromagnetic irradiation. The phosphorylation of Jakl was upregulated after microwave exposure and peaked at 12 h. Jak2 peaked at 0 h after electro-magnetic irradiation and sustained in a high level. Jak3 was slightly affected by electromagnetic irradiation. All the three members of JAKs return to normal at 72 h after electromagnetic irradiation. Conclusion: Microglia cells was activated after electromagnetic irradiation. The phosphorylation of Jaks was upregulated by electromagnetic irradiation. It suggested that JAK/ STAT singnaling pathway was activated after electromagnetic irradiation, which indicated that JAK/STAT signaling pathway may participate in brain microglia activation induced by electromagnetic irradiation. (authors)

  20. Benfotiamine attenuates inflammatory response in LPS stimulated BV-2 microglia.

    Directory of Open Access Journals (Sweden)

    Iva Bozic

    Full Text Available Microglial cells are resident immune cells of the central nervous system (CNS, recognized as key elements in the regulation of neural homeostasis and the response to injury and repair. As excessive activation of microglia may lead to neurodegeneration, therapeutic strategies targeting its inhibition were shown to improve treatment of most neurodegenerative diseases. Benfotiamine is a synthetic vitamin B1 (thiamine derivate exerting potentially anti-inflammatory effects. Despite the encouraging results regarding benfotiamine potential to alleviate diabetic microangiopathy, neuropathy and other oxidative stress-induced pathological conditions, its activities and cellular mechanisms during microglial activation have yet to be elucidated. In the present study, the anti-inflammatory effects of benfotiamine were investigated in lipopolysaccharide (LPS-stimulated murine BV-2 microglia. We determined that benfotiamine remodels activated microglia to acquire the shape that is characteristic of non-stimulated BV-2 cells. In addition, benfotiamine significantly decreased production of pro-inflammatory mediators such as inducible form of nitric oxide synthase (iNOS and NO; cyclooxygenase-2 (COX-2, heat-shock protein 70 (Hsp70, tumor necrosis factor alpha α (TNF-α, interleukin-6 (IL-6, whereas it increased anti-inflammatory interleukin-10 (IL-10 production in LPS stimulated BV-2 microglia. Moreover, benfotiamine suppressed the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2, c-Jun N-terminal kinases (JNK and protein kinase B Akt/PKB. Treatment with specific inhibitors revealed that benfotiamine-mediated suppression of NO production was via JNK1/2 and Akt pathway, while the cytokine suppression includes ERK1/2, JNK1/2 and Akt pathways. Finally, the potentially protective effect is mediated by the suppression of translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB in the nucleus. Therefore

  1. Aldose reductase mediates retinal microglia activation

    International Nuclear Information System (INIS)

    Chang, Kun-Che; Shieh, Biehuoy; Petrash, J. Mark

    2016-01-01

    Retinal microglia (RMG) are one of the major immune cells in charge of surveillance of inflammatory responses in the eye. In the absence of an inflammatory stimulus, RMG reside predominately in the ganglion layer and inner or outer plexiform layers. However, under stress RMG become activated and migrate into the inner nuclear layer (INL) or outer nuclear layer (ONL). Activated RMG in cell culture secrete pro-inflammatory cytokines in a manner sensitive to downregulation by aldose reductase inhibitors. In this study, we utilized CX3CR1"G"F"P mice carrying AR mutant alleles to evaluate the role of AR on RMG activation and migration in vivo. When tested on an AR"W"T background, IP injection of LPS induced RMG activation and migration into the INL and ONL. However, this phenomenon was largely prevented by AR inhibitors or in AR null mice, or was exacerbated in transgenic mice that over-express AR. LPS-induced increases in ocular levels of TNF-α and CX3CL-1 in WT mice were substantially lower in AR null mice or were reduced by AR inhibitor treatment. These studies demonstrate that AR expression in RMG may contribute to the proinflammatory phenotypes common to various eye diseases such as uveitis and diabetic retinopathy. - Highlights: • AR inhibition prevents retinal microglial activation. • Endotoxin-induced ocular cytokine production is reduced in AR null mice. • Overexpression of AR spontaneously induces retinal microglial activation.

  2. Aldose reductase mediates retinal microglia activation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kun-Che; Shieh, Biehuoy; Petrash, J. Mark, E-mail: mark.petrash@ucdenver.edu

    2016-04-29

    Retinal microglia (RMG) are one of the major immune cells in charge of surveillance of inflammatory responses in the eye. In the absence of an inflammatory stimulus, RMG reside predominately in the ganglion layer and inner or outer plexiform layers. However, under stress RMG become activated and migrate into the inner nuclear layer (INL) or outer nuclear layer (ONL). Activated RMG in cell culture secrete pro-inflammatory cytokines in a manner sensitive to downregulation by aldose reductase inhibitors. In this study, we utilized CX3CR1{sup GFP} mice carrying AR mutant alleles to evaluate the role of AR on RMG activation and migration in vivo. When tested on an AR{sup WT} background, IP injection of LPS induced RMG activation and migration into the INL and ONL. However, this phenomenon was largely prevented by AR inhibitors or in AR null mice, or was exacerbated in transgenic mice that over-express AR. LPS-induced increases in ocular levels of TNF-α and CX3CL-1 in WT mice were substantially lower in AR null mice or were reduced by AR inhibitor treatment. These studies demonstrate that AR expression in RMG may contribute to the proinflammatory phenotypes common to various eye diseases such as uveitis and diabetic retinopathy. - Highlights: • AR inhibition prevents retinal microglial activation. • Endotoxin-induced ocular cytokine production is reduced in AR null mice. • Overexpression of AR spontaneously induces retinal microglial activation.

  3. Rod microglia: elongation, alignment, and coupling to form trains across the somatosensory cortex after experimental diffuse brain injury

    Directory of Open Access Journals (Sweden)

    Ziebell Jenna M

    2012-10-01

    Full Text Available Abstract Background Since their discovery, the morphology of microglia has been interpreted to mirror their function, with ramified microglia constantly surveying the micro-environment and rapidly activating when changes occur. In 1899, Franz Nissl discovered what we now recognize as a distinct microglial activation state, microglial rod cells (Stäbchenzellen, which he observed adjacent to neurons. These rod-shaped microglia are typically found in human autopsy cases of paralysis of the insane, a disease of the pre-penicillin era, and best known today from HIV-1-infected brains. Microglial rod cells have been implicated in cortical ‘synaptic stripping’ but their exact role has remained unclear. This is due at least in part to a scarcity of experimental models. Now we have noted these rod microglia after experimental diffuse brain injury in brain regions that have an associated sensory sensitivity. Here, we describe the time course, location, and surrounding architecture associated with rod microglia following experimental diffuse traumatic brain injury (TBI. Methods Rats were subjected to a moderate midline fluid percussion injury (mFPI, which resulted in transient suppression of their righting reflex (6 to 10 min. Multiple immunohistochemistry protocols targeting microglia with Iba1 and other known microglia markers were undertaken to identify the morphological activation of microglia. Additionally, labeling with Iba1 and cell markers for neurons and astrocytes identified the architecture that surrounds these rod cells. Results We identified an abundance of Iba1-positive microglia with rod morphology in the primary sensory barrel fields (S1BF. Although present for at least 4 weeks post mFPI, they developed over the first week, peaking at 7 days post-injury. In the absence of contusion, Iba1-positive microglia appear to elongate with their processes extending from the apical and basal ends. These cells then abut one another and lay adjacent

  4. Single-wall carbon nanohorns inhibited activation of microglia induced by lipopolysaccharide through blocking of Sirt3

    Science.gov (United States)

    Li, Lihong; Zhang, Jinqian; Yang, Yang; Wang, Qiang; Gao, Li; Yang, Yanlong; Chang, Tao; Zhang, Xingye; Xiang, Guoan; Cao, Yongmei; Shi, Zujin; Zhao, Ming; Gao, Guodong

    2013-02-01

    Single-wall carbon nanohorns (SWNHs) have been demonstrated to accumulate in cytotoxic levels within organs of various animal models and cell types, which emerge as a wide range of promising biomedical imaging. Septic encephalopathy (SE) is an early sign of sepsis and associated with an increased rate of morbidity and mortality. Microglia activation plays an important role in neuroinflammation, which contributes to neuronal damage. Inhibition of microglia activation may have therapeutic benefits, which can alleviate the progression of neurodegeneration. Therefore, we investigated the functional changes of mice microglia cell lines pre-treated with or without lipopolysaccharide (LPS) induced by SWNHs. To address this question, the research about direct role of SWNHs on the growth, proliferation, and apoptosis of microglia cell lines in mice (N9 and BV2) pre-treated with or without LPS had been performed. Our results indicate that the particle diameter of SWNHs in water is between 342 to 712 nm. The images in scanning electron microscope showed that SWNHs on polystyrene surface are individual particles. LPS induced activation of mice microglia, promoted its growth and proliferation, and inhibited its apoptosis. SWNHs inhibited proliferation, delayed mitotic entry, and promoted apoptosis of mice microglia cells. The effects followed gradually increasing cultured time and concentrations of SWNHs, especially in cells pre-treated with LPS. SWNHs induced a significantly increase in G1 phase and inhibition of S phase of mice microglia cells in a dose-manner dependent of SWNHs, especially in cells pre-treated with LPS. The transmission electron microscope images showed that individual spherical SWNH particles smaller than 100 nm in diameters were localized inside lysosomes of mice microglia cells. SWNHs inhibited mitotic entry, growth and proliferation of mice microglia cells, and promoted its apoptosis, especially in cells pre-treated with LPS. SWNHs inhibited expression

  5. Autophagy and Microglia: Novel Partners in Neurodegeneration and Aging.

    Science.gov (United States)

    Plaza-Zabala, Ainhoa; Sierra-Torre, Virginia; Sierra, Amanda

    2017-03-09

    Autophagy is emerging as a core regulator of Central Nervous System (CNS) aging and neurodegeneration. In the brain, it has mostly been studied in neurons, where the delivery of toxic molecules and organelles to the lysosome by autophagy is crucial for neuronal health and survival. However, we propose that the (dys)regulation of autophagy in microglia also affects innate immune functions such as phagocytosis and inflammation, which in turn contribute to the pathophysiology of aging and neurodegenerative diseases. Herein, we first describe the basic concepts of autophagy and its regulation, discuss key aspects for its accurate monitoring at the experimental level, and summarize the evidence linking autophagy impairment to CNS senescence and disease. We focus on acute, chronic, and autoimmunity-mediated neurodegeneration, including ischemia/stroke, Alzheimer's, Parkinson's, and Huntington's diseases, and multiple sclerosis. Next, we describe the actual and potential impact of autophagy on microglial phagocytic and inflammatory function. Thus, we provide evidence of how autophagy may affect microglial phagocytosis of apoptotic cells, amyloid-β, synaptic material, and myelin debris, and regulate the progression of age-associated neurodegenerative diseases. We also discuss data linking autophagy to the regulation of the microglial inflammatory phenotype, which is known to contribute to age-related brain dysfunction. Overall, we update the current knowledge of autophagy and microglia, and highlight as yet unexplored mechanisms whereby autophagy in microglia may contribute to CNS disease and senescence.

  6. Arsenic trioxide mediates HAPI microglia inflammatory response and subsequent neuron apoptosis through p38/JNK MAPK/STAT3 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Jiamin [Department of Environmental Health, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Yang, Jianbing [Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001 (China); Zhang, Yan [Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Li, Ting [Department of Environmental Health, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Wang, Cheng [Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Xu, Lingfei; Hu, Qiaoyun; Wang, Xiaoke; Jiang, Shengyang [Department of Environmental Health, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Nie, Xiaoke [Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Chen, Gang, E-mail: chengang@ntu.edu.cn [Department of Environmental Health, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China)

    2016-07-15

    Arsenic is a widely distributed toxic metalloid all over the world. Inorganic arsenic species are supposed to affect astrocytic functions and to cause neuron apoptosis in CNS. Microglias are the key cell type involved in innate immune responses in CNS, and microglia activation has been linked to inflammation and neurotoxicity. In this study, using ELISA, we showed that Arsenic trioxide up-regulated the expression and secretion of IL-1β in a dose-dependent manner and a time-dependent manner in cultured HAPI microglia cells. The secretion of IL-1β caused the apoptosis of SH-SY5Y. These pro-inflammatory responses were inhibited by the STAT3 blocker, AG490 and P38/JNK MAPK blockers SB202190, SP600125. Further, Arsenic trioxide exposure could induce phosphorylation and activation of STAT3, and the translocation of STAT3 from the cytosol to the nucleus in this HAPI microglia cell line. Thus, the STAT3 signaling pathway can be activated after Arsenic trioxide treatment. However, P38/JNK MAPK blockers SB202190, SP600125 also obviously attenuated STAT3 activation and transnuclear transport induced by Arsenic trioxide. In concert with these results, we highlighted that the secretion of IL-1β and STAT3 activation induced by Arsenic trioxide can be mediated by elevation of P38/JNK MAPK in HAPI microglia cells and then induced the toxicity of neurons. - Highlights: • Arsenic trioxide exposure induced expression of IL-β in HAPI microglia. • Arsenic trioxide exposure induced activation of MAPK pathways in HAPI microglia. • Arsenic trioxide exposure induced activation of STAT3 pathways in HAPI microglia. • The expression of IL-β though P38/JNK MAPK/STAT3 pathways in HAPI microglia.

  7. Arsenic trioxide mediates HAPI microglia inflammatory response and subsequent neuron apoptosis through p38/JNK MAPK/STAT3 pathway

    International Nuclear Information System (INIS)

    Mao, Jiamin; Yang, Jianbing; Zhang, Yan; Li, Ting; Wang, Cheng; Xu, Lingfei; Hu, Qiaoyun; Wang, Xiaoke; Jiang, Shengyang; Nie, Xiaoke; Chen, Gang

    2016-01-01

    Arsenic is a widely distributed toxic metalloid all over the world. Inorganic arsenic species are supposed to affect astrocytic functions and to cause neuron apoptosis in CNS. Microglias are the key cell type involved in innate immune responses in CNS, and microglia activation has been linked to inflammation and neurotoxicity. In this study, using ELISA, we showed that Arsenic trioxide up-regulated the expression and secretion of IL-1β in a dose-dependent manner and a time-dependent manner in cultured HAPI microglia cells. The secretion of IL-1β caused the apoptosis of SH-SY5Y. These pro-inflammatory responses were inhibited by the STAT3 blocker, AG490 and P38/JNK MAPK blockers SB202190, SP600125. Further, Arsenic trioxide exposure could induce phosphorylation and activation of STAT3, and the translocation of STAT3 from the cytosol to the nucleus in this HAPI microglia cell line. Thus, the STAT3 signaling pathway can be activated after Arsenic trioxide treatment. However, P38/JNK MAPK blockers SB202190, SP600125 also obviously attenuated STAT3 activation and transnuclear transport induced by Arsenic trioxide. In concert with these results, we highlighted that the secretion of IL-1β and STAT3 activation induced by Arsenic trioxide can be mediated by elevation of P38/JNK MAPK in HAPI microglia cells and then induced the toxicity of neurons. - Highlights: • Arsenic trioxide exposure induced expression of IL-β in HAPI microglia. • Arsenic trioxide exposure induced activation of MAPK pathways in HAPI microglia. • Arsenic trioxide exposure induced activation of STAT3 pathways in HAPI microglia. • The expression of IL-β though P38/JNK MAPK/STAT3 pathways in HAPI microglia.

  8. Anti-neuroinflammatory Activity of Elephantopus scaber L. via Activation of Nrf2/HO-1 Signaling and Inhibition of p38 MAPK Pathway in LPS-Induced Microglia BV-2 Cells

    Directory of Open Access Journals (Sweden)

    Chim-Kei Chan

    2017-06-01

    Full Text Available Elephantopus scaber L. (family: Asteraceae has been traditionally utilized as a folkloric medicine and scientifically shown to exhibit anti-inflammatory activities in various in vivo inflammatory models. Given the lack of study on the effect of E. scaber in neuroinflammation, this study aimed to investigate the anti-neuroinflammatory effect and the underlying mechanisms of ethyl acetate fraction from the leaves of E. scaber (ESEAF on the release of pro-inflammatory mediators in lipopolysaccharide (LPS-induced microglia cells (BV-2. Present findings showed that ESEAF markedly attenuated the translocation of NF-κB to nucleus concomitantly with the significant mitigation on the LPS-induced production of NO, iNOS, COX-2, PGE2, IL-1β, and TNF-α. These inflammatory responses were reduced via the inhibition of p38. Besides, ESEAF was shown to possess antioxidant activities evident by the DPPH and SOD scavenging activities. The intracellular catalase enzyme activity was enhanced by ESEAF in the LPS-stimulated BV-2 cells. Furthermore, the formation of ROS induced by LPS in BV-2 cells was reduced upon the exposure to ESEAF. Intriguingly, the reduction of ROS was found in concerted with the activation of Nrf2 and HO-1. It is conceivable that the activation promotes the scavenging power of antioxidant enzymes as well as to ameliorate the inflammatory response in LPS-stimulated BV-2 cells. Finally, the safety profile analysis through oral administration of ESEAF at 2000 mg/kg did not result in any mortalities, adverse effects nor histopathologic abnormalities of organs in mice. Taken altogether, the cumulative findings suggested that ESEAF holds the potential to develop as nutraceutical for the intervention of neuroinflammatory disorders.

  9. Immunosenescence of microglia and macrophages: impact on the ageing central nervous system.

    Science.gov (United States)

    Rawji, Khalil S; Mishra, Manoj K; Michaels, Nathan J; Rivest, Serge; Stys, Peter K; Yong, V Wee

    2016-03-01

    Ageing of the central nervous system results in a loss of both grey and white matter, leading to cognitive decline. Additional injury to both the grey and white matter is documented in many neurological disorders with ageing, including Alzheimer's disease, traumatic brain and spinal cord injury, stroke, and multiple sclerosis. Accompanying neuronal and glial damage is an inflammatory response consisting of activated macrophages and microglia, innate immune cells demonstrated to be both beneficial and detrimental in neurological repair. This article will propose the following: (i) infiltrating macrophages age differently from central nervous system-intrinsic microglia; (ii) several mechanisms underlie the differential ageing process of these two distinct cell types; and (iii) therapeutic strategies that selectively target these diverse mechanisms may rejuvenate macrophages and microglia for repair in the ageing central nervous system. Most responses of macrophages are diminished with senescence, but activated microglia increase their expression of pro-inflammatory cytokines while diminishing chemotactic and phagocytic activities. The senescence of macrophages and microglia has a negative impact on several neurological diseases, and the mechanisms underlying their age-dependent phenotypic changes vary from extrinsic microenvironmental changes to intrinsic changes in genomic integrity. We discuss the negative effects of age on neurological diseases, examine the response of senescent macrophages and microglia in these conditions, and propose a theoretical framework of therapeutic strategies that target the different mechanisms contributing to the ageing phenotype in these two distinct cell types. Rejuvenation of ageing macrophage/microglia may preserve neurological integrity and promote regeneration in the ageing central nervous system. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions

  10. Protective microglia and its regulation in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Weidong Le

    2016-09-01

    Full Text Available Microglia mediated neuroinflammation is a hallmark of Parkinson’s disease (PD. It has been reported that microglia in the brain of PD have both neurotoxic and neuroprotective effects, depending on the microglial activation states. In this review, we will focus on the recent research findings of the neuroprotective role of microglia-mediated neuroinflammation in PD. Accumulating new evidences have indicated that the protective mechanisms of microglia may result from its regulation of transrepression pathways via nuclear receptors, anti-inflammatory responses, neuron-microglia crosstalk, histone modification and microRNA regulation. All of these protective mechanisms of microglia orchestrate with each other to repress the production of neurotoxic inflammatory components. Since the detrimental effects of inflammation overwhelm the protective effects of microglia during the disease progression of PD, exploring an in-depth understanding of the protective mechanisms of microglia and promoting the transformation of beneficial microglia are urgently important for the treatment of PD.

  11. Microglia modulate hippocampal neural precursor activity in response to exercise and aging.

    Science.gov (United States)

    Vukovic, Jana; Colditz, Michael J; Blackmore, Daniel G; Ruitenberg, Marc J; Bartlett, Perry F

    2012-05-09

    Exercise has been shown to positively augment adult hippocampal neurogenesis; however, the cellular and molecular pathways mediating this effect remain largely unknown. Previous studies have suggested that microglia may have the ability to differentially instruct neurogenesis in the adult brain. Here, we used transgenic Csf1r-GFP mice to investigate whether hippocampal microglia directly influence the activation of neural precursor cells. Our results revealed that an exercise-induced increase in neural precursor cell activity was mediated via endogenous microglia and abolished when these cells were selectively removed from hippocampal cultures. Conversely, microglia from the hippocampi of animals that had exercised were able to activate latent neural precursor cells when added to neurosphere preparations from sedentary mice. We also investigated the role of CX(3)CL1, a chemokine that is known to provide a more neuroprotective microglial phenotype. Intraparenchymal infusion of a blocking antibody against the CX(3)CL1 receptor, CX(3)CR1, but not control IgG, dramatically reduced the neurosphere formation frequency in mice that had exercised. While an increase in soluble CX(3)CL1 was observed following running, reduced levels of this chemokine were found in the aged brain. Lower levels of CX(3)CL1 with advancing age correlated with the natural decline in neural precursor cell activity, a state that could be partially alleviated through removal of microglia. These findings provide the first direct evidence that endogenous microglia can exert a dual and opposing influence on neural precursor cell activity within the hippocampus, and that signaling through the CX(3)CL1-CX(3)CR1 axis critically contributes toward this process.

  12. In vivo analysis of the time and spatial activation pattern of microglia in the retina following laser-induced choroidal neovascularization.

    Science.gov (United States)

    Crespo-Garcia, Sergio; Reichhart, Nadine; Hernandez-Matas, Carlos; Zabulis, Xenophon; Kociok, Norbert; Brockmann, Claudia; Joussen, Antonia M; Strauss, Olaf

    2015-10-01

    Microglia play a major role in retinal neovascularization and degeneration and are thus potential targets for therapeutic intervention. In vivo assessment of microglia behavior in disease models can provide important information to understand patho-mechanisms and develop therapeutic strategies. Although scanning laser ophthalmoscope (SLO) permits the monitoring of microglia in transgenic mice with microglia-specific GFP expression, there are fundamental limitations in reliable identification and quantification of activated cells. Therefore, we aimed to improve the SLO-based analysis of microglia using enhanced image processing with subsequent testing in laser-induced neovascularization (CNV). CNV was induced by argon laser in MacGreen mice. Microglia was visualized in vivo by SLO in the fundus auto-fluorescence (FAF) mode and verified ex vivo using retinal preparations. Three image processing algorithms based on different analysis of sequences of images were tested. The amount of recorded frames was limiting the effectiveness of the different algorithms. Best results from short recordings were obtained with a pixel averaging algorithm, further used to quantify spatial and temporal distribution of activated microglia in CNV. Morphologically, different microglia populations were detected in the inner and outer retinal layers. In CNV, the peak of microglia activation occurred in the inner layer at day 4 after laser, lacking an acute reaction. Besides, the spatial distribution of the activation changed by the time over the inner retina. No significant time and spatial changes were observed in the outer layer. An increase in laser power did not increase number of activated microglia. The SLO, in conjunction with enhanced image processing, is suitable for in vivo quantification of microglia activation. This surprisingly revealed that laser damage at the outer retina led to more reactive microglia in the inner retina, shedding light upon a new perspective to approach

  13. Maternal inflammation induces immune activation of fetal microglia and leads to disrupted microglia immune responses, behavior, and learning performance in adulthood

    NARCIS (Netherlands)

    Schaafsma, Wandert; Basterra, Laura Bozal; Jacobs, Sabrina; Brouwer, Nieske; Meerlo, Peter; Schaafsma, Anne; Boddeke, Erik W. G. M.; Eggen, Bart J. L.

    2017-01-01

    Maternal inflammation during pregnancy can have detrimental effects on embryonic development that persist during adulthood. However, the underlying mechanisms and insights in the responsible cell types are still largely unknown. Here we report the effect of maternal inflammation on fetal microglia,

  14. Microglia energy metabolism in metabolic disorder.

    Science.gov (United States)

    Kalsbeek, Martin J T; Mulder, Laurie; Yi, Chun-Xia

    2016-12-15

    Microglia are the resident macrophages of the CNS, and are in charge of maintaining a healthy microenvironment to ensure neuronal survival. Microglia carry out a non-stop patrol of the CNS, make contact with neurons and look for abnormalities, all of which requires a vast amount of energy. This non-signaling energy demand increases after activation by pathogens, neuronal damage or other kinds of stimulation. Of the three major energy substrates - glucose, fatty acids and glutamine - glucose is crucial for microglia survival and several glucose transporters are expressed to supply sufficient glucose influx. Fatty acids are another source of energy for microglia and have also been shown to strongly influence microglial immune activity. Glutamine, although possibly suitable for use as an energy substrate by microglia, has been shown to have neurotoxic effects when overloaded. Microglial fuel metabolism might be associated with microglial reactivity under different pathophysiological conditions and a microglial fuel switch may thus be the underlying cause of hypothalamic dysregulation, which is associated with obesity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Melanocortin peptides inhibit production of proinflammatory cytokines and nitric oxide by activated microglia.

    Science.gov (United States)

    Delgado, R; Carlin, A; Airaghi, L; Demitri, M T; Meda, L; Galimberti, D; Baron, P; Lipton, J M; Catania, A

    1998-06-01

    Inflammatory processes contribute to neurodegenerative disease, stroke, encephalitis, and other central nervous system (CNS) disorders. Activated microglia are a source of cytokines and other inflammatory agents within the CNS and it is therefore important to control glial function in order to preserve neural cells. Melanocortin peptides are pro-opiomelanocortin-derived amino acid sequences that include alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropic hormone (ACTH). These peptides have potent and broad anti-inflammatory effects. We tested effects of alpha-MSH (1-13), alpha-MSH (11-13), and ACTH (1-24) on production of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and nitric oxide (NO) in a cultured murine microglial cell line (N9) stimulated with lipopolysaccharide (LPS) plus interferon gamma (IFN-gamma). Melanocortin peptides inhibited production of these cytokines and NO in a concentration-related fashion, probably by increasing intracellular cAMP. When stimulated with LPS + IFN-gamma, microglia increased release of alpha-MSH. Production of TNF-alpha, IL-6, and NO was greater in activated microglia after innmunoneutralization of endogenous alpha-MSH. The results suggest that alpha-MSH is an autocrine factor in microglia. Because melanocortin peptides inhibit production of pro-inflammatory mediators by activated microglia they might be useful in treatment of inflammatory/degenerative brain disorders.

  16. NDRG2 promoted secreted miR-375 in microvesicles shed from M1 microglia, which induced neuron damage.

    Science.gov (United States)

    Tang, Li-li; Wu, Yuan-bo; Fang, Chuan-qin; Qu, Ping; Gao, Zong-liang

    2016-01-15

    Microglia microvesicles (MVs) has shown to have significant biological functions under normal conditions. A diversity of miRNAs is involved in neuronal development, survival, function, and plasticity, but the exact functional role of NDRG2 and secreted miR-375 in MVs in neuron damage is poorly understood. We investigated the effect of NDRG2 and secreted miR-375 in MVs shed from M1 microglia on neuron damage. Expression of Nos2, Arg-1, miR-375, syntaxin-1A, NDRG2 and Pdk 1 were evaluated using RT-PCR or western blotting. Cell viability of N2A neuron was quantified by a MTT assay. Microglia can be polarized into different functional phenotypes. Expression of NDRG2 and Nos2 were significantly increased by LPS treatment on N9 cells, whereas treatment with IL-4 dramatically suppressed the expression of NDRG2 and remarkably elevated expression of Arg-1. Besides, MVs shed from LPS-treated N9 microglia significantly inhibited cell viability of N2A neurons and expression of syntaxin-1A, and NDRG2 interference reversed the up-regulated miR-375 in LPS-treated N9 microglia and MVs shed from LPS-treated N9 cells. Furthermore, NDRG2 could modulate miR-375 expression in N9 microglia and MVs. And miR-375 inhibitor remarkably elevated Pdk1 expression in N2A neurons. Finally, miR-375 inhibitor could reverse suppression effect of NDRG2 overexpression on cell viability of N2A neurons and expression of syntaxin-1A. Our results demonstrated that NDRG2 promoted secreted miR-375 in microvesicles shed from M1 microglia, which induced neuron damage. The suppression of NDRG2 and secreted miR-375 in MVs shed from M1 microglia may be potential targets for alleviation of neuron damage. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. PLD$ is involved in phagocytosis of microglia: expression and localization changes of PLD4 are correlated with activation state of microglia.

    Directory of Open Access Journals (Sweden)

    Yoshinori Otani

    Full Text Available Phospholipase D4 (PLD4 is a recently identified protein that is mainly expressed in the ionized calcium binding adapter molecule 1 (Iba1-positive microglia in the early postnatal mouse cerebellar white matter. Unlike PLD1 and PLD2, PLD4 exhibits no enzymatic activity for conversion of phosphatidylcholine into choline and phosphatidic acid, and its function is completely unknown. In the present study, we examined the distribution of PLD4 in mouse cerebellar white matter during development and under pathological conditions. Immunohistochemical analysis revealed that PLD4 expression was associated with microglial activation under such two different circumstances. A primary cultured microglia and microglial cell line (MG6 showed that PLD4 was mainly present in the nucleus, except the nucleolus, and expression of PLD4 was upregulated by lipopolysaccharide (LPS stimulation. In the analysis of phagocytosis of LPS-stimulated microglia, PLD4 was co-localized with phagosomes that contained BioParticles. Inhibition of PLD4 expression using PLD4 specific small interfering RNA (siRNA in MG6 cells significantly reduced the ratio of phagocytotic cell numbers. These results suggest that the increased PLD4 in the activation process is involved in phagocytosis of activated microglia in the developmental stages and pathological conditions of white matter.

  18. Resveratrol regulates microglia M1/M2 polarization via PGC-1α in conditions of neuroinflammatory injury.

    Science.gov (United States)

    Yang, Xiaodong; Xu, Shaoqing; Qian, Yiwei; Xiao, Qin

    2017-08-01

    Microglia are the primary cells that exert immune function in the central nervous system (CNS), and accumulating evidence suggests that microglia act as key players in the initiation of neurodegenerative diseases. It is now well recognized that microglia have functional plasticity and dual phenotypes, proinflammatory M1 and anti-inflammatory M2 phenotypes. Inhibiting the M1 phenotype while stimulating the M2 phenotype has been suggested as a potential therapeutic approach for the treatment of neuroinflammation-related diseases. Resveratrol has been demonstrated to exert anti-inflammatory effects by suppressing M1 microglia activation. However, the role of resveratrol in regulating microglia polarization and the molecular mechanisms involved have not been fully clarified. In this study, we tested whether resveratrol could suppress microglia activation by promoting microglia polarization toward the M2 phenotype via PGC-1α by measuring M1 and M2 markers in vitro and in vivo. Our study demonstrated that resveratrol reduced inflammatory damage and promoted microglia polarization to the M2 phenotype in LPS-induced neuroinflammation. In addition, resveratrol ameliorated LPS-induced sickness behavior in mice. The promoting effects of resveratrol on M2 polarization were attenuated by knocking down PGC-1α. PGC-1α not only suppressed LPS-evoked M1 marker expression by inhibition of NF-κB activity but also increased M2 marker expression by coactivation of the STAT6 and STAT3 pathways. We propose that overexpression PGC-1α by resveratrol could be a potential therapeutic approach to suppress neuroinflammation by regulating microglia polarization. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Diclofenac enhances proinflammatory cytokine-induced phagocytosis of cultured microglia via nitric oxide production

    International Nuclear Information System (INIS)

    Kakita, Hiroki; Aoyama, Mineyoshi; Nagaya, Yoshiaki; Asai, Hayato; Hussein, Mohamed Hamed; Suzuki, Mieko; Kato, Shin; Saitoh, Shinji; Asai, Kiyofumi

    2013-01-01

    Influenza-associated encephalopathy (IAE) is a central nervous system complication with a high mortality rate, which is increased significantly by the non-steroidal anti-inflammatory drug diclofenac sodium (DCF). In the present study, we investigated the effects of DCF on brain immune cells (i.e. microglia) stimulated with three proinflammatory cytokines, namely tumor necrosis factor-α, interleukin-1β, and interferon-γ. Similar to previous findings in astrocytes, all three cytokines induced the expression of inducible NO synthase (iNOS), as well as NO production, in microglia. The addition of DCF to the culture system augmented iNOS expression and NO production. Immunocytochemical analysis and the phagocytosis assay revealed that cytokine treatment induced morphological changes to and phagocytosis by the microglia. The addition of DCF to the culture system enhanced microglial activation, as well as the phagocytic activity of cytokine-stimulated microglia. Inhibitors of nuclear factor (NF)-κB inhibited iNOS gene expression in cytokine-stimulated microglia with or without DCF, suggesting that the NF-κB pathway is one of the main signaling pathways involved. The iNOS inhibitor N G -monomethyl-L-arginine (L-NMMA) reduced both cytokine-induced phagocytosis and phagocytosis induced by the combination of cytokines plus DCF. Furthermore, the NO donor sodium nitroprusside induced phagocytosis, indicating that NO production is a key regulator of microglial phagocytosis. In conclusion, DCF acts synergistically with proinflammatory cytokines to increase the production of NO in microglia, leading to phagocytic activity of the activated microglia. These findings, together with previous observations regarding astrocytes, may explain the significant increase in mortality of IAE patients treated with DCF. - Highlights: ► Influenza-associated encephalopathy (IAE) is associated with a high mortality rate. ► Hyperimmunization in the brain is believed to be responsible for IAE

  20. Diclofenac enhances proinflammatory cytokine-induced phagocytosis of cultured microglia via nitric oxide production

    Energy Technology Data Exchange (ETDEWEB)

    Kakita, Hiroki [Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Aoyama, Mineyoshi, E-mail: ao.mine@med.nagoya-cu.ac.jp [Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Nagaya, Yoshiaki; Asai, Hayato [Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Hussein, Mohamed Hamed [Neonatal Intensive Care Unit, Pediatric Hospital, Cairo University, Cairo 11559 (Egypt); Maternal and Child Health Department, VACSERA, 51 Wizaret El-Zeraa-Agouza, Giza 22311 (Egypt); Suzuki, Mieko [Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Kato, Shin [Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Saitoh, Shinji [Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan)

    2013-04-15

    Influenza-associated encephalopathy (IAE) is a central nervous system complication with a high mortality rate, which is increased significantly by the non-steroidal anti-inflammatory drug diclofenac sodium (DCF). In the present study, we investigated the effects of DCF on brain immune cells (i.e. microglia) stimulated with three proinflammatory cytokines, namely tumor necrosis factor-α, interleukin-1β, and interferon-γ. Similar to previous findings in astrocytes, all three cytokines induced the expression of inducible NO synthase (iNOS), as well as NO production, in microglia. The addition of DCF to the culture system augmented iNOS expression and NO production. Immunocytochemical analysis and the phagocytosis assay revealed that cytokine treatment induced morphological changes to and phagocytosis by the microglia. The addition of DCF to the culture system enhanced microglial activation, as well as the phagocytic activity of cytokine-stimulated microglia. Inhibitors of nuclear factor (NF)-κB inhibited iNOS gene expression in cytokine-stimulated microglia with or without DCF, suggesting that the NF-κB pathway is one of the main signaling pathways involved. The iNOS inhibitor N{sup G}-monomethyl-L-arginine (L-NMMA) reduced both cytokine-induced phagocytosis and phagocytosis induced by the combination of cytokines plus DCF. Furthermore, the NO donor sodium nitroprusside induced phagocytosis, indicating that NO production is a key regulator of microglial phagocytosis. In conclusion, DCF acts synergistically with proinflammatory cytokines to increase the production of NO in microglia, leading to phagocytic activity of the activated microglia. These findings, together with previous observations regarding astrocytes, may explain the significant increase in mortality of IAE patients treated with DCF. - Highlights: ► Influenza-associated encephalopathy (IAE) is associated with a high mortality rate. ► Hyperimmunization in the brain is believed to be responsible for

  1. The leech nervous system: a valuable model to study the microglia involvement in regenerative processes.

    Science.gov (United States)

    Le Marrec-Croq, Françoise; Drago, Francesco; Vizioli, Jacopo; Sautière, Pierre-Eric; Lefebvre, Christophe

    2013-01-01

    Microglia are intrinsic components of the central nervous system (CNS). During pathologies in mammals, inflammatory processes implicate the resident microglia and the infiltration of blood cells including macrophages. Functions of microglia appear to be complex as they exhibit both neuroprotective and neurotoxic effects during neuropathological conditions in vivo and in vitro. The medicinal leech Hirudo medicinalis is a well-known model in neurobiology due to its ability to naturally repair its CNS following injury. Considering the low infiltration of blood cells in this process, the leech CNS is studied to specify the activation mechanisms of only resident microglial cells. The microglia recruitment is known to be essential for the usual sprouting of injured axons and does not require any other glial cells. The present review will describe the questions which are addressed to understand the nerve repair. They will discuss the implication of leech factors in the microglial accumulation, the identification of nerve cells producing these molecules, and the study of different microglial subsets. Those questions aim to better understand the mechanisms of microglial cell recruitment and their crosstalk with damaged neurons. The study of this dialog is necessary to elucidate the balance of the inflammation leading to the leech CNS repair.

  2. The Leech Nervous System: A Valuable Model to Study the Microglia Involvement in Regenerative Processes

    Directory of Open Access Journals (Sweden)

    Françoise Le Marrec-Croq

    2013-01-01

    Full Text Available Microglia are intrinsic components of the central nervous system (CNS. During pathologies in mammals, inflammatory processes implicate the resident microglia and the infiltration of blood cells including macrophages. Functions of microglia appear to be complex as they exhibit both neuroprotective and neurotoxic effects during neuropathological conditions in vivo and in vitro. The medicinal leech Hirudo medicinalis is a well-known model in neurobiology due to its ability to naturally repair its CNS following injury. Considering the low infiltration of blood cells in this process, the leech CNS is studied to specify the activation mechanisms of only resident microglial cells. The microglia recruitment is known to be essential for the usual sprouting of injured axons and does not require any other glial cells. The present review will describe the questions which are addressed to understand the nerve repair. They will discuss the implication of leech factors in the microglial accumulation, the identification of nerve cells producing these molecules, and the study of different microglial subsets. Those questions aim to better understand the mechanisms of microglial cell recruitment and their crosstalk with damaged neurons. The study of this dialog is necessary to elucidate the balance of the inflammation leading to the leech CNS repair.

  3. Coupled Proliferation and Apoptosis Maintain the Rapid Turnover of Microglia in the Adult Brain

    Directory of Open Access Journals (Sweden)

    Katharine Askew

    2017-01-01

    Full Text Available Summary: Microglia play key roles in brain development, homeostasis, and function, and it is widely assumed that the adult population is long lived and maintained by self-renewal. However, the precise temporal and spatial dynamics of the microglial population are unknown. We show in mice and humans that the turnover of microglia is remarkably fast, allowing the whole population to be renewed several times during a lifetime. The number of microglial cells remains steady from late postnatal stages until aging and is maintained by the spatial and temporal coupling of proliferation and apoptosis, as shown by pulse-chase studies, chronic in vivo imaging of microglia, and the use of mouse models of dysregulated apoptosis. Our results reveal that the microglial population is constantly and rapidly remodeled, expanding our understanding of its role in the maintenance of brain homeostasis. : The mechanism or mechanisms underlying microglial homeostasis are unknown. Askew et al. show that microglia self-renewal is maintained by coupled proliferation and apoptosis, resulting in a stable microglia number over a mouse or human lifetime. Keywords: self-renewal, BrdU, CSF1R, CX3CR1, Macgreen, Vav-Bcl2, RNA-seq

  4. Brucella abortus-activated microglia induce neuronal death through primary phagocytosis.

    Science.gov (United States)

    Rodríguez, Ana M; Delpino, M Victoria; Miraglia, M Cruz; Costa Franco, Miriam M; Barrionuevo, Paula; Dennis, Vida A; Oliveira, Sergio C; Giambartolomei, Guillermo H

    2017-07-01

    Inflammation has long been implicated as a contributor to pathogenesis in neurobrucellosis. Many of the associated neurocognitive symptoms of neurobrucellosis may be the result of neuronal dysfunction resulting from the inflammatory response induced by Brucella abortus infection in the central nervous system. In this manuscript, we describe an immune mechanism for inflammatory activation of microglia that leads to neuronal death upon B. abortus infection. B. abortus was unable to infect or harm primary cultures of mouse neurons. However, when neurons were co-cultured with microglia and infected with B. abortus significant neuronal loss occurred. This phenomenon was dependent on TLR2 activation by Brucella lipoproteins. Neuronal death was not due to apoptosis, but it was dependent on the microglial release of nitric oxide (NO). B. abortus infection stimulated microglial proliferation, phagocytic activity and engulfment of neurons. NO secreted by B. abortus-activated microglia induced neuronal exposure of the "eat-me" signal phosphatidylserine (PS). Blocking of PS-binding to protein milk fat globule epidermal growth factor-8 (MFG-E8) or microglial vitronectin receptor-MFG-E8 interaction was sufficient to prevent neuronal loss by inhibiting microglial phagocytosis without affecting their activation. Taken together, our results indicate that B. abortus is not directly toxic to neurons; rather, these cells become distressed and are killed by phagocytosis in the inflammatory surroundings generated by infected microglia. Neuronal loss induced by B. abortus-activated microglia may explain, in part, the neurological deficits observed during neurobrucellosis. © 2017 Wiley Periodicals, Inc.

  5. Are microglia minding us? Digging up the unconscious mind-brain relationship from a neuropsychoanalytic approach.

    Directory of Open Access Journals (Sweden)

    Takahiro A. Kato

    2013-02-01

    Full Text Available The unconscious mind-brain relationship remains unresolved. From the perspective of neuroscience, neuronal networks including synapses have been dominantly believed to play crucial roles in human mental activities, while glial contribution to mental activities has long been ignored. Recently, it has been suggested that microglia, glial cells with immunological/inflammatory functions, play important roles in psychiatric disorders. Newly revealed microglial roles, such as constant direct contact with synapses even in normal brain, have defied the common traditional belief that microglia do not contribution to neuronal networks. Recent human neuroeconomic investigations with healthy volunteers using minocycline, an antibiotic with inhibitory effects on microglial activation, suggest that microglia may unconsciously modulate human social behaviors as noise.We herein propose a novel unconscious mind structural system in the brain centering on microglia from a neuropsychoanalytic approach. At least to some extent, microglial activation in the brain may activate unconscious drives as psychological immune memory/reaction in the mind, and result in various emotions, traumatic reactions, psychiatric symptoms including suicidal behaviors, and (psychoanalytic transference during interpersonal relationships. Microglia have the potential to bridge the huge gap between neuroscience, biological psychiatry, psychology and psychoanalysis as a key player to connect the conscious and the unconscious world.

  6. TNF-α from hippocampal microglia induces working memory deficits by acute stress in mice.

    Science.gov (United States)

    Ohgidani, Masahiro; Kato, Takahiro A; Sagata, Noriaki; Hayakawa, Kohei; Shimokawa, Norihiro; Sato-Kasai, Mina; Kanba, Shigenobu

    2016-07-01

    The role of microglia in stress responses has recently been highlighted, yet the underlying mechanisms of action remain unresolved. The present study examined disruption in working memory due to acute stress using the water-immersion resistant stress (WIRS) test in mice. Mice were subjected to acute WIRS, and biochemical, immunohistochemical, and behavioral assessments were conducted. Spontaneous alternations (working memory) significantly decreased after exposure to acute WIRS for 2h. We employed a 3D morphological analysis and site- and microglia-specific gene analysis techniques to detect microglial activity. Morphological changes in hippocampal microglia were not observed after acute stress, even when assessing ramification ratios and cell somata volumes. Interestingly, hippocampal tumor necrosis factor (TNF)-α levels were significantly elevated after acute stress, and acute stress-induced TNF-α was produced by hippocampal-ramified microglia. Conversely, plasma concentrations of TNF-α were not elevated after acute stress. Etanercept (TNF-α inhibitor) recovered working memory deficits in accordance with hippocampal TNF-α reductions. Overall, results suggest that TNF-α from hippocampal microglia is a key contributor to early-stage stress-to-mental responses. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. [Knockdown of PRDX6 in microglia reduces neuron viability after OGD/R injury].

    Science.gov (United States)

    Tan, Li; Zhao, Yong; Jiang, Beibei; Yang, Bo; Zhang, Hui

    2016-08-01

    Objective To observe the effects of peroxiredoxin 6 (PRDX6) knockdown in the microglia on neuron viability after oxygen-glucose deprivation and reoxygenation (OGD/R). Methods Microglia was treated with lentivirus PRDX6-siRNA and Ca(2+)-independent phospholipase A2 (iPLA2) inhibitor, 1-hexadecyl-3-(trifluoroethgl)-sn-glycerol-2 phosphomethanol (MJ33). Twenty-four hours later, it was co-cultured with primary neuron to establish the microglia-neuron co-culture OGD/R model. According to the different treatment of microglia, the cells were divided into normal group, OGD/R group, negative control-siRNA treated OGD/R group, PRDX6-siRNA treated OGD/R group and PRDX6-siRNA combined with MJ33 treated OGD/R group. Western blot analysis and real-time quantitative PCR were respectively performed to detect PRDX6 protein and mRNA levels after knockdown of PRDX6 in microglia. The iPLA2 activity was measured by ELISA. MTS and lactate dehydrogenase (LDH) assay were used to measure neuron viability and cell damage. The oxidative stress level of neuron was determined by measuring superoxide dismutase (SOD) and malonaldehyde (MDA) content. Results In PRDX6-siRNA group, neuron viability was inhibited and oxidative stress damage was aggravated compared with OGD/R group. In PRDX6-siRNA combined with MJ33 group, cell viability was promoted and oxidative stress damage was alleviated compared with PRDX6-siRNA group. Conclusion PRDX6 in microglia protects neuron against OGD/R-induced injury, and iPLA2 activity has an effect on PRDX6.

  8. Population control of resident and immigrant microglia by mitosis and apoptosis

    DEFF Research Database (Denmark)

    Wirenfeldt, Martin; Dissing-Olesen, Lasse; Babcock, Alicia

    2007-01-01

    microglia often occurred in clusters, some having recently incorporated bromodeoxyuridine, showing that proliferation had occurred. Annexin V labeling and staining for activated caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling showed that apoptotic mechanisms participate...... in dissolution of the microglial response. Using bone marrow chimeric mice, we found that the lesion-induced proliferative capacity of resident microglia superseded that of immigrant microglia, whereas lesion-induced kinetics of apoptosis were comparable. Microglial numbers and responses were severely reduced...... in bone marrow chimeric mice. These results broaden our understanding of the microglial response to neural damage by demonstrating that simultaneously occurring mitosis and apoptosis regulate expansion and reduction of both resident and immigrant microglial cell populations....

  9. In Vivo Imaging of Microglia Turnover in the Mouse Retina After Ionizing Radiation and Dexamethasone Treatment

    DEFF Research Database (Denmark)

    Alt, C.; Runnels, J. M.; Mortensen, L. J.

    2014-01-01

    irradiation with a confocal scanning laser ophthalmoscope that we custom-built specifically for multicolor imaging of the murine retina. RESULTS. Ionizing radiation resulted in loss of 75% of the resident retinal microglia population after 70 days. Recruitment of BMDCs was delayed with respect...... dexamethasone preserves resident microglia and minimizes recruitment of BMDCs after ionizing radiation exposure and BMT.......PURPOSE. Gamma irradiation and bone marrow transplantation (BMT) are established clinical procedures for the treatment of hematologic malignancies. The radiation targets cells in the bone marrow, but injury to other tissues, including the central nervous system (CNS), have been reported. Here, we...

  10. Human glioblastoma-associated microglia/monocytes express a distinct RNA profile compared to human control and murine samples.

    Science.gov (United States)

    Szulzewsky, Frank; Arora, Sonali; de Witte, Lot; Ulas, Thomas; Markovic, Darko; Schultze, Joachim L; Holland, Eric C; Synowitz, Michael; Wolf, Susanne A; Kettenmann, Helmut

    2016-08-01

    Glioblastoma (GBM) is the most aggressive brain tumor in adults. It is strongly infiltrated by microglia and peripheral monocytes that support tumor growth. In the present study we used RNA sequencing to compare the expression profile of CD11b(+) human glioblastoma-associated microglia/monocytes (hGAMs) to CD11b(+) microglia isolated from non-tumor samples. Hierarchical clustering and principal component analysis showed a clear separation of the two sample groups and we identified 334 significantly regulated genes in hGAMs. In comparison to human control microglia hGAMs upregulated genes associated with mitotic cell cycle, cell migration, cell adhesion, and extracellular matrix organization. We validated the expression of several genes associated with extracellular matrix organization in samples of human control microglia, hGAMs, and the hGAMs-depleted fraction via qPCR. The comparison to murine GAMs (mGAMs) showed that both cell populations share a significant fraction of upregulated transcripts compared with their respective controls. These genes were mostly related to mitotic cell cycle. However, in contrast to murine cells, human GAMs did not upregulate genes associated to immune activation. Comparison of human and murine GAMs expression data to several data sets of in vitro-activated human macrophages and murine microglia showed that, in contrast to mGAMs, hGAMs share a smaller overlap to these data sets in general and in particular to cells activated by proinflammatory stimulation with LPS + INFγ or TNFα. Our findings provide new insights into the biology of human glioblastoma-associated microglia/monocytes and give detailed information about the validity of murine experimental models. GLIA 2016 GLIA 2016;64:1416-1436. © 2016 Wiley Periodicals, Inc.

  11. Acid sphingomyelinase (aSMase) deficiency leads to abnormal microglia behavior and disturbed retinal function

    Energy Technology Data Exchange (ETDEWEB)

    Dannhausen, Katharina; Karlstetter, Marcus; Caramoy, Albert [Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne (Germany); Volz, Cornelia; Jägle, Herbert [Department of Ophthalmology, University Hospital Regensburg, Regensburg (Germany); Liebisch, Gerhard [Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg (Germany); Utermöhlen, Olaf [Institute for Medical Microbiology, Immunology and Hygiene and Center for Molecular Medicine Cologne, University of Cologne, Cologne (Germany); Langmann, Thomas, E-mail: thomas.langmann@uk-koeln.de [Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne (Germany)

    2015-08-21

    Mutations in the acid sphingomyelinase (aSMase) coding gene sphingomyelin phosphodiesterase 1 (SMPD1) cause Niemann-Pick disease (NPD) type A and B. Sphingomyelin storage in cells of the mononuclear phagocyte system cause hepatosplenomegaly and severe neurodegeneration in the brain of NPD patients. However, the effects of aSMase deficiency on retinal structure and microglial behavior have not been addressed in detail yet. Here, we demonstrate that retinas of aSMase{sup −/−} mice did not display overt neuronal degeneration but showed significantly reduced scotopic and photopic responses in electroretinography. In vivo fundus imaging of aSMase{sup −/−} mice showed many hyperreflective spots and staining for the retinal microglia marker Iba1 revealed massive proliferation of retinal microglia that had significantly enlarged somata. Nile red staining detected prominent phospholipid inclusions in microglia and lipid analysis showed significantly increased sphingomyelin levels in retinas of aSMase{sup −/−} mice. In conclusion, the aSMase-deficient mouse is the first example in which microglial lipid inclusions are directly related to a loss of retinal function. - Highlights: • aSMase-deficient mice show impaired retinal function and reactive microgliosis. • aSMase-deficient microglia express pro-inflammatory transcripts. • aSMase-deficient microglia proliferate and have increased cell body size. • In vivo imaging shows hyperreflective spots in the fundus of aSMase-deficient mice. • aSMase-deficient microglia accumulate sphingolipid-rich intracellular deposits.

  12. Reactive oxygen species mediate nitric oxide production through ERK/JNK MAPK signaling in HAPI microglia after PFOS exposure

    International Nuclear Information System (INIS)

    Wang, Cheng; Nie, Xiaoke; Zhang, Yan; Li, Ting; Mao, Jiamin; Liu, Xinhang; Gu, Yiyang; Shi, Jiyun; Xiao, Jing; Wan, Chunhua; Wu, Qiyun

    2015-01-01

    Perfluorooctane sulfonate (PFOS), an emerging persistent contaminant that is commonly encountered during daily life, has been shown to exert toxic effects on the central nervous system (CNS). However, the molecular mechanisms underlying the neurotoxicity of PFOS remain largely unknown. It has been widely acknowledged that the inflammatory mediators released by hyper-activated microglia play vital roles in the pathogenesis of various neurological diseases. In the present study, we examined the impact of PFOS exposure on microglial activation and the release of proinflammatory mediators, including nitric oxide (NO) and reactive oxidative species (ROS). We found that PFOS exposure led to concentration-dependent NO and ROS production by rat HAPI microglia. We also discovered that there was rapid activation of the ERK/JNK MAPK signaling pathway in the HAPI microglia following PFOS treatment. Moreover, the PFOS-induced iNOS expression and NO production were attenuated after the inhibition of ERK or JNK MAPK by their corresponding inhibitors, PD98059 and SP600125. Interestingly, NAC, a ROS inhibitor, blocked iNOS expression, NO production, and activation of ERK and JNK MAPKs, which suggested that PFOS-mediated microglial NO production occurs via a ROS/ERK/JNK MAPK signaling pathway. Finally, by exposing SH-SY5Y cells to PFOS-treated microglia-conditioned medium, we demonstrated that NO was responsible for PFOS-mediated neuronal apoptosis. - Highlights: • PFOS exposure induced expression of iNOS and production of NO in HAPI microglia. • PFOS induced the production of ROS in HAPI microglia. • ERK/JNK MAPK pathways were activated following PFOS exposure in HAPI microglia. • NO released by HAPI microglia participated in the apoptosis of SH-SY5Y cells.

  13. Reactive oxygen species mediate nitric oxide production through ERK/JNK MAPK signaling in HAPI microglia after PFOS exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng; Nie, Xiaoke; Zhang, Yan [Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Li, Ting; Mao, Jiamin [Department of Labor and Environmental Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Liu, Xinhang [Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Gu, Yiyang; Shi, Jiyun [Department of Labor and Environmental Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Xiao, Jing [Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Wan, Chunhua [Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China); Wu, Qiyun, E-mail: wqy@ntu.edu.cn [Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu 226001 (China)

    2015-10-15

    Perfluorooctane sulfonate (PFOS), an emerging persistent contaminant that is commonly encountered during daily life, has been shown to exert toxic effects on the central nervous system (CNS). However, the molecular mechanisms underlying the neurotoxicity of PFOS remain largely unknown. It has been widely acknowledged that the inflammatory mediators released by hyper-activated microglia play vital roles in the pathogenesis of various neurological diseases. In the present study, we examined the impact of PFOS exposure on microglial activation and the release of proinflammatory mediators, including nitric oxide (NO) and reactive oxidative species (ROS). We found that PFOS exposure led to concentration-dependent NO and ROS production by rat HAPI microglia. We also discovered that there was rapid activation of the ERK/JNK MAPK signaling pathway in the HAPI microglia following PFOS treatment. Moreover, the PFOS-induced iNOS expression and NO production were attenuated after the inhibition of ERK or JNK MAPK by their corresponding inhibitors, PD98059 and SP600125. Interestingly, NAC, a ROS inhibitor, blocked iNOS expression, NO production, and activation of ERK and JNK MAPKs, which suggested that PFOS-mediated microglial NO production occurs via a ROS/ERK/JNK MAPK signaling pathway. Finally, by exposing SH-SY5Y cells to PFOS-treated microglia-conditioned medium, we demonstrated that NO was responsible for PFOS-mediated neuronal apoptosis. - Highlights: • PFOS exposure induced expression of iNOS and production of NO in HAPI microglia. • PFOS induced the production of ROS in HAPI microglia. • ERK/JNK MAPK pathways were activated following PFOS exposure in HAPI microglia. • NO released by HAPI microglia participated in the apoptosis of SH-SY5Y cells.

  14. Priming of microglia in a DNA-repair deficient model of accelerated aging

    NARCIS (Netherlands)

    Raj, Divya D. A.; Jaarsma, Dick; Holtman, Inge R.; Olah, Marta; Ferreira, Filipa M.; Schaafsma, Wandert; Brouwer, Nieske; Meijer, Michel M.; de Waard, Monique C.; van der Pluijm, Ingrid; Brandt, Renata; Kreft, Karim L.; Laman, Jon D.; de Haan, Gerald; Biber, Knut P. H.; Hoeijmakers, Jan H. J.; Eggen, Bart J. L.; Boddeke, Hendrikus W. G. M.

    Aging is associated with reduced function, degenerative changes, and increased neuroinflammation of the central nervous system (CNS). Increasing evidence suggests that changes in microglia cells contribute to the age-related deterioration of the CNS. The most prominent age-related change of

  15. Feeding the beast: can microglia in the senescent brain be regulated by diet?

    Science.gov (United States)

    Johnson, Rodney W

    2015-01-01

    Microglial cells, resident macrophages in the central nervous system (CNS), are relatively quiescent but can respond to signals from the peripheral immune system and induce neuroinflammation. In aging, microglia tend to transition to the M1 pro-inflammatory state and become hypersensitive to messages emerging from immune-to-brain signaling pathways. Thus, whereas in younger individuals where microglia respond to signals from the peripheral immune system and induce a well-controlled neuroinflammatory response that is adaptive (e.g., when well controlled, fever and sickness behavior facilitate recovery from infection), in older individuals with an infection, microglia overreact and produce excessive levels of inflammatory cytokines causing behavioral pathology including cognitive dysfunction. Importantly, recent studies indicate a number of naturally occurring bioactive compounds present in certain foods have anti-inflammatory properties and are capable of mitigating brain microglial cells. These include, e.g., flavonoid and non-flavonoid compounds in fruits and vegetables, and n-3 polyunsaturated fatty acids (PUFA) in oily fish. Thus, dietary bioactives have potential to restore the population of microglial cells in the senescent brain to a more quiescent state. The pragmatic concept to constrain microglia through dietary intervention is significant because neuroinflammation and cognitive deficits are co-morbid factors in many chronic inflammatory diseases. Controlling microglial cell reactivity has important consequences for preserving adult neurogenesis, neuronal structure and function, and cognition. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Progranulin Is a Chemoattractant for Microglia and Stimulates Their Endocytic Activity

    Science.gov (United States)

    Pickford, Fiona; Marcus, Jacob; Camargo, Luiz Miguel; Xiao, Qiurong; Graham, Danielle; Mo, Jan-Rung; Burkhardt, Matthew; Kulkarni, Vinayak; Crispino, Jamie; Hering, Heike; Hutton, Michael

    2011-01-01

    Mutations resulting in progranulin haploinsufficiency cause disease in patients with a subset of frontotemporal lobar degeneration; however, the biological functions of progranulin in the brain remain unknown. To address this subject, the present study initially assessed changes in gene expression and cytokine secretion in rat primary cortical neurons treated with progranulin. Molecular pathways enriched in the progranulin gene set included cell adhesion and cell motility pathways and pathways involved in growth and development. Secretion of cytokines and several chemokines linked to chemoattraction but not inflammation were also increased from progranulin-treated primary neurons. Therefore, whether progranulin is involved in recruitment of immune cells in the brain was investigated. Localized lentiviral expression of progranulin in C57BL/6 mice resulted in an increase of Iba1-positive microglia around the injection site. Moreover, progranulin alone was sufficient to promote migration of primary mouse microglia in vitro. Primary microglia and C4B8 cells demonstrated more endocytosis of amyloid β1-42 when treated with progranulin. These data demonstrate that progranulin acts as a chemoattractant in the brain to recruit or activate microglia and can increase endocytosis of extracellular peptides such as amyloid β. PMID:21224065

  17. Microglia - insights into immune system structure, function, and reactivity in the central nervous system

    DEFF Research Database (Denmark)

    Wirenfeldt, Martin; Babcock, Alicia A; Vinters, Harry V

    2011-01-01

    Microglia are essential cellular components of a well-functioning central nervous system (CNS). The development and establishment of the microglial population differs from the other major cell populations in the CNS i.e. neurons and macroglia (astrocytes and oligodendrocytes). This different onto...

  18. Arginase-1 expressing microglia in close proximity to motor neurons were increased early in disease progression in canine degenerative myelopathy, a model of amyotrophic lateral sclerosis.

    Science.gov (United States)

    Toedebusch, Christine M; Snyder, John C; Jones, Maria R; Garcia, Virginia B; Johnson, Gayle C; Villalón, Eric L; Coates, Joan R; Garcia, Michael L

    2018-04-01

    Toxicity within superoxide dismutase-1 (SOD1)-associated familial amyotrophic lateral sclerosis (ALS) is non-cell autonomous with direct contribution from microglia. Microglia exhibit variable expression of neuroprotective and neurotoxic molecules throughout disease progression. The mechanisms regulating microglial phenotype within ALS are not well understood. This work presents a first study to examine the specific microglial phenotypic response in close association to motor neurons in a naturally occurring disease model of ALS, canine degenerative myelopathy (DM). Microglia closely associated with motor neurons were increased in all stages of DM progression, although only DM Late reached statistical significance. Furthermore, the number of arginase-1 expressing microglia per motor neuron were significantly increased in early stages of DM, whereas the number of inducible nitric oxide synthase (iNOS)-expressing microglia per motor neuron was indistinguishable from aged controls at all stages of disease. Fractalkine, a chemotactic molecule for microglia, was expressed in motor neurons, and the fractalkine receptor was specifically localized to microglia. However, we found no correlation between microglial response and lumbar spinal cord fractalkine levels. Taken together, these data suggest that arginase-1-expressing microglia are recruited to the motor neuron early in DM disease through a fractalkine-independent mechanism. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Neuroprotective effect of curcumin against oxidative damage in BV-2 microglia and high intraocular pressure animal model.

    Science.gov (United States)

    Yue, Yan-Kun; Mo, Bin; Zhao, Jun; Yu, Ya-Jie; Liu, Lu; Yue, Chang-Li; Liu, Wu

    2014-10-01

    The involvement of local and systemic oxidative stress in intraocular pressure (IOP) elevation and optic nerve damage has been hypothesized in the pathogenesis of glaucoma. In this study, we aim to evaluate the antioxidant effects of curcumin in BV-2 microglia oxidative damage and assess its neuroprotective effects in a chronic high IOP rat model. BV-2 microglia cell line was used in an in vitro study and Wistar rats were used in an in vivo study. Cultured BV-2 microglia cells were pretreated with 10, 1, or 0.1 μM curcumin for 1 h, and sustained oxidative stress was induced by subjecting BV-2 microglia to 200 μM hydrogen peroxide (H2O2) for 24 h. MTT assay was used to determine cell viability. Changes of intracellular reactive oxygen species (ROS) and apoptosis were analyzed by flow cytometry. Three episcleral veins were cauterized to induce high IOP in Wistar rats and measured by Tonopen. After 6 weeks of treatment with curcumin (10 mg/kg/day) by intragastric administration, surviving of retinal ganglion cells was quantified. Activation of caspase 3, cytochrome c, BAX, and BCL2 was quantified by Western blotting both in BV-2 microglia and in animal model. Data were analyzed with the GraphPad Prism 5.0 software, and Pcurcumin, the cell viability increased and the intracellular ROS and apoptosis significantly decreased. In the in vivo study, chronic mild IOP elevation was induced for 4 weeks. In the curcumin-treated group, curcumin protected rat BV-2 microglia from death significantly. In both H2O2-treated BV-2 microglia and glaucoma models, caspase 3, cytochrome c, and BAX were downregulated and BCL2 was upregulated in the curcumin-treated group. Curcumin affords neuroprotective effects by inhibiting oxidative damage and could be a new or adjunctive treatment for glaucoma.

  20. The subpopulation of microglia sensitive to neurotransmitters/neurohormones is modulated by stimulation with LPS, interferon-γ, and IL-4.

    Science.gov (United States)

    Pannell, Maria; Szulzewsky, Frank; Matyash, Vitali; Wolf, Susanne A; Kettenmann, Helmut

    2014-05-01

    Recently, neurotransmitters/neurohormones have been identified as factors controlling the function of microglia, the immune competent cells of the central nervous system. In this study, we compared the responsiveness of microglia to neurotransmitters/neurohormones. We freshly isolated microglia from healthy adult C57Bl/6 mice and found that only a small fraction (1-20%) responded to the application of endothelin, histamine, substance P, serotonin, galanin, somatostatin, angiotensin II, vasopressin, neurotensin, dopamine, or nicotine. In cultured microglia from neonatal and adult mice, a similarly small population of cells responded to these neurotransmitters/neurohormones. To induce a proinflammatory phenotype, we applied lipopolysaccaride (LPS) or interferon-gamma (IFN-γ) to the cultures for 24 h. Several of the responding populations increased; however, there was no uniform pattern when comparing adult with neonatal microglia or LPS with IFN-γ treatment. IL-4 as an anti-inflammatory substance increased the histamine-, substance P-, and somatostatin-sensitive populations only in microglia from adult, but not in neonatal cells. We also found that the expression of different receptors was not strongly correlated, indicating that there are many different populations of microglia with a distinct set of receptors. Our results demonstrate that microglial cells are a heterogeneous population with respect to their sensitivity to neurotransmitters/neurohormones and that they are more responsive in defined activation states. Copyright © 2014 Wiley Periodicals, Inc.

  1. Bone marrow-derived microglia infiltrate into the paraventricular nucleus of chronic psychological stress-loaded mice.

    Directory of Open Access Journals (Sweden)

    Koji Ataka

    Full Text Available BACKGROUND: Microglia of the central nervous system act as sentinels and rapidly react to infection or inflammation. The pathophysiological role of bone marrow-derived microglia is of particular interest because they affect neurodegenerative disorders and neuropathic pain. The hypothesis of the current study is that chronic psychological stress (chronic PS induces the infiltration of bone marrow-derived microglia into hypothalamus by means of chemokine axes in brain and bone marrow. METHODS AND FINDINGS: Here we show that bone marrow-derived microglia specifically infiltrate the paraventricular nucleus (PVN of mice that received chronic PS. Bone marrow derived-microglia are CX3CR1(lowCCR2(+CXCR4(high, as distinct from CX3CR1(highCCR2(-CXCR4(low resident microglia, and express higher levels of interleukin-1β (IL-1β but lower levels of tumor necrosis factor-α (TNF-α. Chronic PS stimulates the expression of monocyte chemotactic protein-1 (MCP-1 in PVN neurons, reduces stromal cell-derived factor-1 (SDF-1 in the bone marrow and increases the frequency of CXCR4(+ monocytes in peripheral circulation. And then a chemokine (C-C motif receptor 2 (CCR2 or a β3-adrenoceptor blockade prevents infiltration of bone marrow-derived microglia in the PVN. CONCLUSION: Chronic PS induces the infiltration of bone marrow-derived microglia into PVN, and it is conceivable that the MCP-1/CCR2 axis in PVN and the SDF-1/CXCR4 axis in bone marrow are involved in this mechanism.

  2. Nanometer size diesel exhaust particles are selectively toxic to dopaminergic neurons: the role of microglia, phagocytosis, and NADPH oxidase.

    Science.gov (United States)

    Block, M L; Wu, X; Pei, Z; Li, G; Wang, T; Qin, L; Wilson, B; Yang, J; Hong, J S; Veronesi, B

    2004-10-01

    The contributing role of environmental factors to the development of Parkinson's disease has become increasingly evident. We report that mesencephalic neuron-glia cultures treated with diesel exhaust particles (DEP; 0.22 microM) (5-50 microg/ml) resulted in a dose-dependent decrease in dopaminergic (DA) neurons, as determined by DA-uptake assay and tyrosine-hydroxylase immunocytochemistry (ICC). The selective toxicity of DEP for DA neurons was demonstrated by the lack of DEP effect on both GABA uptake and Neu-N immunoreactive cell number. The critical role of microglia was demonstrated by the failure of neuron-enriched cultures to exhibit DEP-induced DA neurotoxicity, where DEP-induced DA neuron death was reinstated with the addition of microglia to neuron-enriched cultures. OX-42 ICC staining of DEP treated neuron-glia cultures revealed changes in microglia morphology indicative of activation. Intracellular reactive oxygen species and superoxide were produced from enriched-microglia cultures in response to DEP. Neuron-glia cultures from NADPH oxidase deficient (PHOX-/-) mice were insensitive to DEP neurotoxicity when compared with control mice (PHOX+/+). Cytochalasin D inhibited DEP-induced superoxide production in enriched-microglia cultures, implying that DEP must be phagocytized by microglia to produce superoxide. Together, these in vitro data indicate that DEP selectively damages DA neurons through the phagocytic activation of microglial NADPH oxidase and consequent oxidative insult.

  3. Glial Cells: The Other Cells of the Nervous System

    Indian Academy of Sciences (India)

    secrete growth factors that act on neurons and other glial cells. from activated microglia. .... Microglia in Alzheimer's disease: Alzheimer's disease is charac- terized by deposition of ... trigger the recruitment ofT lymphocytes into the inflammatory.

  4. Microglia: An Interface between the Loss of Neuroplasticity and Depression

    Directory of Open Access Journals (Sweden)

    Gaurav Singhal

    2017-09-01

    Full Text Available Depression has been widely accepted as a major psychiatric disease affecting nearly 350 million people worldwide. Research focus is now shifting from studying the extrinsic and social factors of depression to the underlying molecular causes. Microglial activity is shown to be associated with pathological conditions, such as psychological stress, pathological aging, and chronic infections. These are primary immune effector cells in the CNS and regulate the extensive dialogue between the nervous and the immune systems in response to different immunological, physiological, and psychological stressors. Studies have suggested that during stress and pathologies, microglia play a significant role in the disruption of neuroplasticity and have detrimental effects on neuroprotection causing neuroinflammation and exacerbation of depression. After a systematic search of literature databases, relevant articles on the microglial regulation of bidirectional neuroimmune pathways affecting neuroplasticity and leading to depression were reviewed. Although, several hypotheses have been proposed for the microglial role in the onset of depression, it is clear that all molecular pathways to depression are linked through microglia-associated neuroinflammation and hippocampal degeneration. Molecular factors such as an excess of glucocorticoids and changes in gene expression of neurotrophic factors, as well as neuro active substances secreted by gut microbiota have also been shown to affect microglial morphology and phenotype resulting in depression. This review aims to critically analyze the various molecular pathways associated with the microglial role in depression.

  5. Scutellarin Attenuates Microglia-Mediated Neuroinflammation and Promotes Astrogliosis in Cerebral Ischemia - A Therapeutic Consideration.

    Science.gov (United States)

    Wu, Chun-Yun; Fang, Ming; Karthikeyan, Aparna; Yuan, Yun; Ling, Eng-Ang

    2017-01-01

    Neuroinflammation plays an important role in different brain diseases including acute brain injuries such as cerebral ischemic stroke and chronic neurodegenerative diseases e.g. Alzheimer's disease etc. The central player in this is the activated microglia, which produce substantial amounts of proinflammatory mediators that may exacerbate the disease. Associated with microglia activation is astrogliosis characterized by hypertrophic astrocytes with increased expression of proinflammatory cytokines, neurotrophic factors, stem cell, neuronal and proliferation markers, all these are crucial for reconstruction of damaged tissue and ultimate restoration of neurological functions. Here, we review the roles of activated microglia and reactive astrocytes in brain diseases with special reference to cerebral ischemia, and the effects of scutellarin, a Chinese herbal extract on both glial cells. We first reviewed the close spatial relation between activated microglia and reactive astrocytes as it suggests that both glial cells work in concert for tissue reconstruction and repair. Secondly, we have identified scutellarin as a putative therapeutic agent as it has been found to not only suppress microglial activation thus ameliorating neuroinflammation, but also enhance astrocytic reaction. In the latter, scutellarin amplified the astrocytic reaction by upregulating the expression of neurotrophic factors among others thus indicating its neuroprotective role. Remarkably, the effects of scutellarin on reactive astrocytes were mediated by activated microglia supporting a functional "cross-talk" between the two glial types. This review highlights some of our recent findings taking into consideration of others demonstrating the beneficial effects of scutellarin on both glial cell types in cerebral ischemia as manifested by improvement of neurological functions. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Minocycline counter-regulates pro-inflammatory microglia responses in the retina and protects from degeneration.

    Science.gov (United States)

    Scholz, Rebecca; Sobotka, Markus; Caramoy, Albert; Stempfl, Thomas; Moehle, Christoph; Langmann, Thomas

    2015-11-17

    retina and down-regulated the expression of the microglial activation marker translocator protein (18 kDa) (TSPO), CD68, and activated microglia/macrophage whey acidic protein (AMWAP) already 1 day after light exposure. Furthermore, RNA-seq analyses revealed the potential of minocycline to globally counter-regulate pro-inflammatory gene transcription in the light-damaged retina. The severe thinning of the outer retina and the strong induction of photoreceptor apoptosis induced by light challenge were nearly completely prevented by minocycline treatment as indicated by a preserved retinal structure and a low number of apoptotic cells. Minocycline potently counter-regulates microgliosis and light-induced retinal damage, indicating a promising concept for the treatment of retinal pathologies.

  7. Presenilin 2 is the predominant γ-secretase in microglia and modulates cytokine release.

    Directory of Open Access Journals (Sweden)

    Suman Jayadev

    2010-12-01

    Full Text Available Presenilin 1 (PS1 and Presenilin 2 (PS2 are the enzymatic component of the γ-secretase complex that cleaves amyloid precursor protein (APP to release amyloid beta (Aβ peptide. PS deficiency in mice results in neuroinflammation and neurodegeneration in the absence of accumulated Aβ. We hypothesize that PS influences neuroinflammation through its γ-secretase action in CNS innate immune cells. We exposed primary murine microglia to a pharmacological γ-secretase inhibitor which resulted in exaggerated release of TNFα and IL-6 in response to lipopolysaccharide. To determine if this response was mediated by PS1, PS2 or both we used shRNA to knockdown each PS in a murine microglia cell line. Knockdown of PS1 did not lead to decreased γ-secretase activity while PS2 knockdown caused markedly decreased γ-secretase activity. Augmented proinflammatory cytokine release was observed after knockdown of PS2 but not PS1. Proinflammatory stimuli increased microglial PS2 gene transcription and protein in vitro. This is the first demonstration that PS2 regulates CNS innate immunity. Taken together, our findings suggest that PS2 is the predominant γ-secretase in microglia and modulates release of proinflammatory cytokines. We propose PS2 may participate in a negative feedback loop regulating inflammatory behavior in microglia.

  8. Population control of resident and immigrant microglia by mitosis and apoptosis.

    Science.gov (United States)

    Wirenfeldt, Martin; Dissing-Olesen, Lasse; Anne Babcock, Alicia; Nielsen, Marianne; Meldgaard, Michael; Zimmer, Jens; Azcoitia, Iñigo; Leslie, Robert Graham Quinton; Dagnaes-Hansen, Frederik; Finsen, Bente

    2007-08-01

    Microglial population expansion occurs in response to neural damage via processes that involve mitosis and immigration of bone marrow-derived cells. However, little is known of the mechanisms that regulate clearance of reactive microglia, when microgliosis diminishes days to weeks later. We have investigated the mechanisms of microglial population control in a well-defined model of reactive microgliosis in the mouse dentate gyrus after perforant pathway axonal lesion. Unbiased stereological methods and flow cytometry demonstrate significant lesion-induced increases in microglial numbers. Reactive microglia often occurred in clusters, some having recently incorporated bromodeoxyuridine, showing that proliferation had occurred. Annexin V labeling and staining for activated caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling showed that apoptotic mechanisms participate in dissolution of the microglial response. Using bone marrow chimeric mice, we found that the lesion-induced proliferative capacity of resident microglia superseded that of immigrant microglia, whereas lesion-induced kinetics of apoptosis were comparable. Microglial numbers and responses were severely reduced in bone marrow chimeric mice. These results broaden our understanding of the microglial response to neural damage by demonstrating that simultaneously occurring mitosis and apoptosis regulate expansion and reduction of both resident and immigrant microglial cell populations.

  9. The Role of Microglia in Diabetic Retinopathy: Inflammation, Microvasculature Defects and Neurodegeneration

    Science.gov (United States)

    Altmann, Christine

    2018-01-01

    Diabetic retinopathy is a common complication of diabetes mellitus, which appears in one third of all diabetic patients and is a prominent cause of vision loss. First discovered as a microvascular disease, intensive research in the field identified inflammation and neurodegeneration to be part of diabetic retinopathy. Microglia, the resident monocytes of the retina, are activated due to a complex interplay between the different cell types of the retina and diverse pathological pathways. The trigger for developing diabetic retinopathy is diabetes-induced hyperglycemia, accompanied by leukostasis and vascular leakages. Transcriptional changes in activated microglia, mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and extracellular signal–regulated kinase (ERK) signaling pathways, results in release of various pro-inflammatory mediators, including cytokines, chemokines, caspases and glutamate. Activated microglia additionally increased proliferation and migration. Among other consequences, these changes in microglia severely affected retinal neurons, causing increased apoptosis and subsequent thinning of the nerve fiber layer, resulting in visual loss. New potential therapeutics need to interfere with these diabetic complications even before changes in the retina are diagnosed, to prevent neuronal apoptosis and blindness in patients. PMID:29301251

  10. Enriched environment decreases microglia and brain macrophages inflammatory phenotypes through adiponectin-dependent mechanisms: Relevance to depressive-like behavior.

    Science.gov (United States)

    Chabry, Joëlle; Nicolas, Sarah; Cazareth, Julie; Murris, Emilie; Guyon, Alice; Glaichenhaus, Nicolas; Heurteaux, Catherine; Petit-Paitel, Agnès

    2015-11-01

    Regulation of neuroinflammation by glial cells plays a major role in the pathophysiology of major depression. While astrocyte involvement has been well described, the role of microglia is still elusive. Recently, we have shown that Adiponectin (ApN) plays a crucial role in the anxiolytic/antidepressant neurogenesis-independent effects of enriched environment (EE) in mice; however its mechanisms of action within the brain remain unknown. Here, we show that in a murine model of depression induced by chronic corticosterone administration, the hippocampus and the hypothalamus display increased levels of inflammatory cytokines mRNA, which is reversed by EE housing. By combining flow cytometry, cell sorting and q-PCR, we show that microglia from depressive-like mice adopt a pro-inflammatory phenotype characterized by higher expression levels of IL-1β, IL-6, TNF-α and IκB-α mRNAs. EE housing blocks pro-inflammatory cytokine gene induction and promotes arginase 1 mRNA expression in brain-sorted microglia, indicating that EE favors an anti-inflammatory activation state. We show that microglia and brain-macrophages from corticosterone-treated mice adopt differential expression profiles for CCR2, MHC class II and IL-4recα surface markers depending on whether the mice are kept in standard environment or EE. Interestingly, the effects of EE were abolished when cells are isolated from ApN knock-out mouse brains. When injected intra-cerebroventricularly, ApN, whose level is specifically increased in cerebrospinal fluid of depressive mice raised in EE, rescues microglia phenotype, reduces pro-inflammatory cytokine production by microglia and blocks depressive-like behavior in corticosterone-treated mice. Our data suggest that EE-induced ApN increase within the brain regulates microglia and brain macrophages phenotype and activation state, thus reducing neuroinflammation and depressive-like behaviors in mice. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Microglia and Aging: The Role of the TREM2–DAP12 and CX3CL1-CX3CR1 Axes

    Directory of Open Access Journals (Sweden)

    Carmen Mecca

    2018-01-01

    Full Text Available Depending on the species, microglial cells represent 5–20% of glial cells in the adult brain. As the innate immune effector of the brain, microglia are involved in several functions: regulation of inflammation, synaptic connectivity, programmed cell death, wiring and circuitry formation, phagocytosis of cell debris, and synaptic pruning and sculpting of postnatal neural circuits. Moreover, microglia contribute to some neurodevelopmental disorders such as Nasu-Hakola disease (NHD, and to aged-associated neurodegenerative diseases, such as Alzheimer’s disease (AD, Parkinson’s disease (PD, and others. There is evidence that human and rodent microglia may become senescent. This event determines alterations in the microglia activation status, associated with a chronic inflammation phenotype and with the loss of neuroprotective functions that lead to a greater susceptibility to the neurodegenerative diseases of aging. In the central nervous system (CNS, Triggering Receptor Expressed on Myeloid Cells 2-DNAX activation protein 12 (TREM2-DAP12 is a signaling complex expressed exclusively in microglia. As a microglial surface receptor, TREM2 interacts with DAP12 to initiate signal transduction pathways that promote microglial cell activation, phagocytosis, and microglial cell survival. Defective TREM2-DAP12 functions play a central role in the pathogenesis of several diseases. The CX3CL1 (fractalkine-CX3CR1 signaling represents the most important communication channel between neurons and microglia. The expression of CX3CL1 in neurons and of its receptor CX3CR1 in microglia determines a specific interaction, playing fundamental roles in the regulation of the maturation and function of these cells. Here, we review the role of the TREM2-DAP12 and CX3CL1-CX3CR1 axes in aged microglia and the involvement of these pathways in physiological CNS aging and in age-associated neurodegenerative diseases.

  12. Involvement of Phosphatidylinositol 3-Kinase-Mediated Up-Regulation of IκBα in Anti-Inflammatory Effect of Gemfibrozil in Microglia1

    OpenAIRE

    Jana, Malabendu; Jana, Arundhati; Liu, Xiaojuan; Ghosh, Sankar; Pahan, Kalipada

    2007-01-01

    The present study underlines the importance of PI3K in mediating the anti-inflammatory effect of gemfibrozil, a prescribed lipid-lowering drug for humans, in mouse microglia. Gemfibrozil inhibited LPS-induced expression of inducible NO synthase (iNOS) and proinflammatory cytokines in mouse BV-2 microglial cells and primary microglia. By overexpressing wild-type and dominant-negative constructs of peroxisome proliferator-activated receptor-α (PPAR-α) in microglial cells and isolating primary m...

  13. VEGF receptor blockade markedly reduces retinal microglia/macrophage infiltration into laser-induced CNV.

    Directory of Open Access Journals (Sweden)

    Hu Huang

    Full Text Available Although blocking VEGF has a positive effect in wet age-related macular degeneration (AMD, the effect of blocking its receptors remains unclear. This was an investigation of the effect of VEGF receptor (VEGFR 1 and/or 2 blockade on retinal microglia/macrophage infiltration in laser-induced choroidal neovascularization (CNV, a model of wet AMD. CNV lesions were isolated by laser capture microdissection at 3, 7, and 14 days after laser and analyzed by RT-PCR and immunofluorescence staining for mRNA and protein expression, respectively. Neutralizing antibodies for VEGFR1 or R2 and the microglia inhibitor minocycline were injected intraperitoneally (IP. Anti-CD11b, CD45 and Iba1 antibodies were used to confirm the cell identity of retinal microglia/macrophage, in the RPE/choroidal flat mounts or retinal cross sections. CD11b(+, CD45(+ or Iba1(+ cells were counted. mRNA of VEGFR1 and its three ligands, PlGF, VEGF-A (VEGF and VEGF-B, were expressed at all stages, but VEGFR2 were detected only in the late stage. PlGF and VEGF proteins were expressed at 3 and 7 days after laser. Anti-VEGFR1 (MF1 delivered IP 3 days after laser inhibited infiltration of leukocyte populations, largely retinal microglia/macrophage to CNV, while anti-VEGFR2 (DC101 had no effect. At 14 days after laser, both MF1 and DC101 antibodies markedly inhibited retinal microglia/macrophage infiltration into CNV. Therefore, VEGFR1 and R2 play differential roles in the pathogenesis of CNV: VEGFR1 plays a dominant role at 3 days after laser; but both receptors play pivotal roles at 14 days after laser. In vivo imaging demonstrated accumulation of GFP-expressing microglia into CNV in both CX3CR1(gfp/gfp and CX3CR1(gfp/+ mice. Minocycline treatment caused a significant increase in lectin(+ cells in the sub-retinal space anterior to CNV and a decrease in dextran-perfused neovessels compared to controls. Targeting the chemoattractant molecules that regulate trafficking of retinal microglia

  14. MICROGLIA ACTIVATION AS A BIOMARKER FOR TRAUMATIC BRAIN INJURY

    Directory of Open Access Journals (Sweden)

    Diana G Hernadez-Ontiveros

    2013-03-01

    Full Text Available Traumatic brain injury (TBI has become the signature wound of wars in Afghanistan and Iraq. Injury may result from a mechanical force, a rapid acceleration-deceleration movement, or a blast wave. A cascade of secondary cell death events ensues after the initial injury. In particular, multiple inflammatory responses accompany TBI. A series of inflammatory cytokines and chemokines spreads to normal brain areas juxtaposed to the core impacted tissue. Among the repertoire of immune cells involved, microglia is a key player in propagating inflammation to tissues neighboring the core site of injury. Neuroprotective drug trials in TBI have failed, likely due to their sole focus on abrogating neuronal cell death and ignoring the microglia response despite these inflammatory cells’ detrimental effects on the brain. Another relevant point to consider is the veracity of results of animal experiments due to deficiencies in experimental design, such as incomplete or inadequate method description, data misinterpretation and reporting may introduce bias and give false-positive results. Thus, scientific publications should follow strict guidelines that include randomization, blinding, sample-size estimation and accurate handling of all data (Landis et al., 2012. A prolonged state of inflammation after brain injury may linger for years and predispose patients to develop other neurological disorders, such as Alzheimer’s disease. TBI patients display progressive and long-lasting impairments in their physical, cognitive, behavioral, and social performance. Here, we discuss inflammatory mechanisms that accompany TBI in an effort to increase our understanding of the dynamic pathological condition as the disease evolves over time and begin to translate these findings for defining new and existing inflammation-based biomarkers and treatments for TBI.

  15. Protective effects of agmatine on lipopolysaccharide-injured microglia and inducible nitric oxide synthase activity.

    Science.gov (United States)

    Ahn, Soo Kyung; Hong, Samin; Park, Yu Mi; Choi, Ja Yong; Lee, Won Taek; Park, Kyung Ah; Lee, Jong Eun

    2012-12-17

    Proinflammatory factors released from activated microglia contribute to maintaining homeostasis against various noxious stimuli in the central nervous system. If excessive, however, they may initiate a pathologic neuroinflammatory process. In this investigation, we evaluated whether agmatine, a primary polyamine known to protect neurons, reduces lipopolysaccharide (LPS)-induced damage to microglia in vitro and in vivo. For in vitro study, BV2-immortalized murine microglia were exposed to LPS with agmatine treatment. After 24hours, cell viability and the amount of nitrite generated were determined. For in vivo study, LPS was microinjected into the corpus callosum of adult male albino mice. Agmatine was intraperitoneally administered at the time of injury. Brains were evaluated 24hours after LPS microinjection to check for immunoreactivity with a microglial marker of ionized calcium binding adaptor molecule 1 (Iba1) and inducible nitric oxide synthase (iNOS). Using western blot analysis, protein expression of iNOS as well as that of the proinflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1β, was determined. Agmatine significantly reduced the LPS-induced BV2 microglial cytotoxicity from over 80% to less than 60% (pAgmatine also decreased the activities of microglia and iNOS induced by LPS microinjection into corpus callosum. Our findings reveal that agmatine attenuates LPS-induced microglial damage and suggest that agmatine may serve as a novel therapeutic strategy for neuroinflammatory diseases. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. E3 Ubiquitin Ligase c-cbl Inhibits Microglia Activation After Chronic Constriction Injury.

    Science.gov (United States)

    Xue, Pengfei; Liu, Xiaojuan; Shen, Yiming; Ju, Yuanyuan; Lu, Xiongsong; Zhang, Jinlong; Xu, Guanhua; Sun, Yuyu; Chen, Jiajia; Gu, Haiyan; Cui, Zhiming; Bao, Guofeng

    2018-06-22

    E3 ubiquitin ligase c-Caritas B cell lymphoma (c-cbl) is associated with negative regulation of receptor tyrosine kinases, signal transduction of antigens and cytokine receptors, and immune response. However, the expression and function of c-cbl in the regulation of neuropathic pain after chronic constriction injury (CCI) are unknown. In rat CCI model, c-cbl inhibited the activation of spinal cord microglia and the release of pro-inflammatory factors including tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and interleukin 6 (IL-6), which alleviated mechanical and heat pain through down-regulating extracellular signal-regulated kinase (ERK) pathway. Additionally, exogenous TNF-α inhibited c-cbl protein level vice versa. In the primary microglia transfected with c-cbl siRNA, when treated with TNF-α or TNF-α inhibitor, the corresponding secretion of IL-1β and IL-6 did not change. In summary, CCI down-regulated c-cbl expression and induced the activation of microglia, then activated microglia released inflammatory factors via ERK signaling to cause pain. Our data might supply a novel molecular target for the therapy of CCI-induced neuropathic pain.

  17. Modulation of Toll-like receptor-mediated activation of Microglia

    NARCIS (Netherlands)

    Putten, C. M.-T. van der

    2015-01-01

    Microglia are the resident macrophages of the central nervous system (CNS). Like other tissue macrophages, microglia have many different functions under physiological as well as pathological conditions. Microglia can contribute to the initiation, progression and resolution of disease processes and

  18. P2X7 signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand

    Directory of Open Access Journals (Sweden)

    Lu Ying-mei

    2012-07-01

    Full Text Available Abstract Background The cerebral microvascular occlusion elicits microvascular injury which mimics the different degrees of stroke severity observed in patients, but the mechanisms underlying these embolic injuries are far from understood. The Fas ligand (FasL-Fas system has been implicated in a number of pathogenic states. Here, we examined the contribution of microglia-derived FasL to brain inflammatory injury, with a focus on the potential to suppress the FasL increase by inhibition of the P2X7-FasL signaling with pharmacological or genetic approaches during ischemia. Methods The cerebral microvascular occlusion was induced by microsphere injection in experimental animals. Morphological changes in microglial cells were studied immunohistochemically. The biochemical analyses were used to examine the intracellular changes of P2X7/FasL signaling. The BV-2 cells and primary microglia from mice genetically deficient in P2X7 were used to further establish a linkage between microglia activation and FasL overproduction. Results The FasL expression was continuously elevated and was spatiotemporally related to microglia activation following microsphere embolism. Notably, P2X7 expression concomitantly increased in microglia and presented a distribution pattern that was similar to that of FasL in ED1-positive cells at pathological process of microsphere embolism. Interestingly, FasL generation in cultured microglia cells subjected to oxygen-glucose deprivation-treated neuron-conditioned medium was prevented by the silencing of P2X7. Furthermore, FasL induced the migration of BV-2 microglia, whereas the neutralization of FasL with a blocking antibody was highly effective in inhibiting ischemia-induced microglial mobility. Similar results were observed in primary microglia from wild-type mice or mice genetically deficient in P2X7. Finally, the degrees of FasL overproduction and neuronal death were consistently reduced in P2X7−/− mice compared with wild

  19. Regulation of progranulin expression in human microglia and proteolysis of progranulin by matrix metalloproteinase-12 (MMP-12.

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    Hyeon-Sook Suh

    Full Text Available The essential role of progranulin (PGRN as a neurotrophic factor has been demonstrated by the discovery that haploinsufficiency due to GRN gene mutations causes frontotemporal lobar dementia. In addition to neurons, microglia in vivo express PGRN, but little is known about the regulation of PGRN expression by microglia.In the current study, we examined the regulation of expression and function of PGRN, its proteolytic enzyme macrophage elastase (MMP-12, as well as the inhibitor of PGRN proteolysis, secretory leukocyte protease inhibitor (SLPI, in human CNS cells.Cultures of primary human microglia and astrocytes were stimulated with the TLR ligands (LPS or poly IC, Th1 cytokines (IL-1/IFNγ, or Th2 cytokines (IL-4, IL-13. Results were analyzed by Q-PCR, immunoblotting or ELISA. The roles of MMP-12 and SLPI in PGRN cleavage were also examined.Unstimulated microglia produced nanogram levels of PGRN, and PGRN release from microglia was suppressed by the TLR ligands or IL-1/IFNγ, but increased by IL-4 or IL-13. Unexpectedly, while astrocytes stimulated with proinflammatory factors released large amounts of SLPI, none were detected in microglial cultures. We also identified MMP-12 as a PGRN proteolytic enzyme, and SLPI as an inhibitor of MMP-12-induced PGRN proteolysis. Experiments employing PGRN siRNA demonstrated that microglial PGRN was involved in the cytokine and chemokine production following TLR3/4 activation, with its effect on TNFα being the most conspicuous.Our study is the first detailed examination of PGRN in human microglia. Our results establish microglia as a significant source of PGRN, and MMP-12 and SLPI as modulators of PGRN proteolysis. Negative and positive regulation of microglial PGRN release by the proinflammatory/Th1 and the Th2 stimuli, respectively, suggests a fundamentally different aspect of PGRN regulation compared to other known microglial activation products. Microglial PGRN appears to function as an endogenous

  20. Microglia Transcriptome Changes in a Model of Depressive Behavior after Immune Challenge.

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    Dianelys Gonzalez-Pena

    Full Text Available 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

  1. Enhanced uptake of multiple sclerosis-derived myelin by THP-1 macrophages and primary human microglia.

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    Hendrickx, Debbie A E; Schuurman, Karianne G; van Draanen, Michael; Hamann, Jörg; Huitinga, Inge

    2014-03-31

    The pathological hallmark of multiple sclerosis (MS) is myelin phagocytosis. It remains unclear why microglia and macrophages demyelinate axons in MS, but previously found or yet-unknown changes in the myelin of MS patients could contribute to this process. We therefore studied whether myelin from normal-appearing white matter (NAWM) of MS donors is phagocytosed more efficiently than myelin from control donors. Myelin was isolated from 11 MS and 12 control brain donors and labeled with the pH-sensitive fluorescent dye pHrodo to quantify uptake in lysosomes. Phagocytosis by differentiated THP-1 macrophages and by primary human microglia was quantified with flow cytometry. Whereas myelin uptake by THP-1 macrophages reached a plateau after approximately 24 hours, uptake by primary human microglia showed an almost linear increase over a 72-hour period. Data were statistically analyzed with the Mann-Whitney U test. MS-derived myelin was phagocytosed more efficiently by THP-1 macrophages after 6-hour incubation (P = 0.001 for the percentage of myelin-phagocytosing cells and P = 0.0005 for total myelin uptake) and after 24-hour incubation (P = 0.0006 and P = 0.0001, respectively), and by microglia after 24-hour incubation (P = 0.0106 for total myelin uptake). This enhanced uptake was not due to differences in the oxidation status of the myelin. Interestingly, myelin phagocytosis correlated negatively with the age of myelin donors, whereas the age of microglia donors showed a positive trend with myelin phagocytosis. Myelin isolated from normal-appearing white matter of MS donors was phagocytosed more efficiently than was myelin isolated from control brain donors by both THP-1 macrophages and primary human microglia. These data indicate that changes in MS myelin might precede phagocyte activation and subsequent demyelination in MS. Identifying these myelin changes responsible for enhancing phagocytic ability could be an interesting therapeutic target to

  2. Polysaccharides from Ganoderma lucidum attenuate microglia-mediated neuroinflammation and modulate microglial phagocytosis and behavioural response.

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    Cai, Qing; Li, Yuanyuan; Pei, Gang

    2017-03-24

    Ganoderma lucidum (GL) has been widely used in Asian countries for hundreds of years to promote health and longevity. The pharmacological functions of which had been classified, including the activation of innate immune responses, suppression of tumour and modulation of cell proliferations. Effective fractions of Ganoderma lucidum polysaccharides (GLP) had already been reported to regulate the immune system. Nevertheless, the role of GLP in the microglia-mediated neuroinflammation has not been sufficiently elucidated. Further, GLP effect on microglial behavioural modulations in correlation with the inflammatory responses remains to be unravelled. The aim of this work was to quantitatively analyse the contributions of GLP on microglia. The BV2 microglia and primary mouse microglia were stimulated by lipopolysaccharides (LPS) and amyloid beta 42 (Aβ 42 ) oligomer, respectively. Investigation on the effect of GLP was carried by quantitative determination of the microglial pro- and anti-inflammatory cytokine expressions and behavioural modulations including migration, morphology and phagocytosis. Analysis of microglial morphology and phagocytosis modulations was confirmed in the zebrafish brain. Quantitative results revealed that GLP down-regulates LPS- or Aβ-induced pro-inflammatory cytokines and promotes anti-inflammatory cytokine expressions in BV-2 and primary microglia. In addition, GLP attenuates inflammation-related microglial migration, morphological alterations and phagocytosis probabilities. We also showed that modulations of microglial behavioural responses were associated with MCP-1 and C1q expressions. Overall, our study provides an insight into the GLP regulation of LPS- and Aβ-induced neuroinflammation and serves an implication that the neuroprotective function of GLP might be achieved through modulation of microglial inflammatory and behavioural responses.

  3. In acute experimental autoimmune encephalomyelitis, infiltrating macrophages are immune activated, whereas microglia remain immune suppressed.

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    Vainchtein, I D; Vinet, J; Brouwer, N; Brendecke, S; Biagini, G; Biber, K; Boddeke, H W G M; Eggen, B J L

    2014-10-01

    Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system (CNS) characterized by loss of myelin accompanied by infiltration of T-lymphocytes and monocytes. Although it has been shown that these infiltrates are important for the progression of MS, the role of microglia, the resident macrophages of the CNS, remains ambiguous. Therefore, we have compared the phenotypes of microglia and macrophages in a mouse model for MS, experimental autoimmune encephalomyelitis (EAE). In order to properly discriminate between these two cell types, microglia were defined as CD11b(pos) CD45(int) Ly-6C(neg) , and infiltrated macrophages as CD11b(pos) CD45(high) Ly-6C(pos) . During clinical EAE, microglia displayed a weakly immune-activated phenotype, based on the expression of MHCII, co-stimulatory molecules (CD80, CD86, and CD40) and proinflammatory genes [interleukin-1β (IL-1β) and tumour necrosis factor- α (TNF-α)]. In contrast, CD11b(pos) CD45(high) Ly-6C(pos) infiltrated macrophages were strongly activated and could be divided into two populations Ly-6C(int) and Ly-6C(high) , respectively. Ly-6C(high) macrophages contained less myelin than Ly-6C(int) macrophages and expression levels of the proinflammatory cytokines IL-1β and TNF-α were higher in Ly-6C(int) macrophages. Together, our data show that during clinical EAE, microglia are only weakly activated whereas infiltrated macrophages are highly immune reactive. © 2014 Wiley Periodicals, Inc.

  4. Neurodegeneration severity can be predicted from early microglia alterations monitored in vivo in a mouse model of chronic glaucoma

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    Alejandra Bosco

    2015-05-01

    Full Text Available Microglia serve key homeostatic roles, and respond to neuronal perturbation and decline with a high spatiotemporal resolution. The course of all chronic CNS pathologies is thus paralleled by local microgliosis and microglia activation, which begin at early stages of the disease. However, the possibility of using live monitoring of microglia during early disease progression to predict the severity of neurodegeneration has not been explored. Because the retina allows live tracking of fluorescent microglia in their intact niche, here we investigated their early changes in relation to later optic nerve neurodegeneration. To achieve this, we used the DBA/2J mouse model of inherited glaucoma, which develops progressive retinal ganglion cell degeneration of variable severity during aging, and represents a useful model to study pathogenic mechanisms of retinal ganglion cell decline that are similar to those in human glaucoma. We imaged CX3CR1+/GFP microglial cells in vivo at ages ranging from 1 to 5 months by confocal scanning laser ophthalmoscopy (cSLO and quantified cell density and morphological activation. We detected early microgliosis at the optic nerve head (ONH, where axonopathy first manifests, and could track attenuation of this microgliosis induced by minocycline. We also observed heterogeneous and dynamic patterns of early microglia activation in the retina. When the same animals were aged and analyzed for the severity of optic nerve pathology at 10 months of age, we found a strong correlation with the levels of ONH microgliosis at 3 to 4 months. Our findings indicate that live imaging and monitoring the time course and levels of early retinal microgliosis and microglia activation in glaucoma could serve as indicators of future neurodegeneration severity.

  5. 6-Mercaptopurine attenuates tumor necrosis factor-? production in microglia through Nur77-mediated transrepression and PI3K/Akt/mTOR signaling-mediated translational regulation

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    Huang, Hsin-Yi; Chang, Hui-Fen; Tsai, Ming-Jen; Chen, Jhih-Si; Wang, Mei-Jen

    2016-01-01

    Background The pathogenesis of several neurodegenerative diseases often involves the microglial activation and associated inflammatory processes. Activated microglia release pro-inflammatory factors that may be neurotoxic. 6-Mercaptopurine (6-MP) is a well-established immunosuppressive drug. Common understanding of their immunosuppressive properties is largely limited to peripheral immune cells. However, the effect of 6-MP in the central nervous system, especially in microglia in the context ...

  6. Microglia P2Y13 Receptors Prevent Astrocyte Proliferation Mediated by P2Y1 Receptors

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    Clara Quintas

    2018-05-01

    Full Text Available Cerebral inflammation is a common feature of several neurodegenerative diseases that requires a fine interplay between astrocytes and microglia to acquire appropriate phenotypes for an efficient response to neuronal damage. During brain inflammation, ATP is massively released into the extracellular medium and converted into ADP. Both nucleotides acting on P2 receptors, modulate astrogliosis through mechanisms involving microglia-astrocytes communication. In previous studies, primary cultures of astrocytes and co-cultures of astrocytes and microglia were used to investigate the influence of microglia on astroglial proliferation induced by ADPβS, a stable ADP analog. In astrocyte cultures, ADPβS increased cell proliferation through activation of P2Y1 and P2Y12 receptors, an effect abolished in co-cultures (of astrocytes with ∼12.5% microglia. The possibility that the loss of the ADPβS-mediated effect could have been caused by a microglia-induced degradation of ADPβS or by a preferential microglial localization of P2Y1 or P2Y12 receptors was excluded. Since ADPβS also activates P2Y13 receptors, the contribution of microglial P2Y13 receptors to prevent the proliferative effect of ADPβS in co-cultures was investigated. The results obtained indicate that P2Y13 receptors are low expressed in astrocytes and mainly expressed in microglia. Furthermore, in co-cultures, ADPβS induced astroglial proliferation in the presence of the selective P2Y13 antagonist MRS 2211 (3 μM and of the selective P2Y12 antagonist AR-C66096 (0.1 μM, suggesting that activation of microglial P2Y12 and P2Y13 receptors may induce the release of messengers that inhibit astroglial proliferation mediated by P2Y1,12 receptors. In this microglia-astrocyte paracrine communication, P2Y12 receptors exert opposite effects in astroglial proliferation as a result of its cellular localization: cooperating in astrocytes with P2Y1 receptors to directly stimulate proliferation and in

  7. Microglia M2A Polarization as Potential Link between Food Allergy and Autism Spectrum Disorders

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    Hans O. Kalkman

    2017-12-01

    Full Text Available Atopic diseases are frequently co-morbid with autism spectrum disorders (ASD. Allergic responses are associated with an activation of mast cells, innate lymphoid cells, and Th2 cells. These cells produce type-2 cytokines (IL4 and IL13, which stimulate microglia and macrophages to adopt a phenotype referred to as ‘alternative activation’ or ‘M2A’. M2A-polarized macrophages and microglia play a physiological role in tissue repair by secreting growth factors such as brain-derived neurotrophic factor (BDNF and insulin-like growth factor-1. In ASD there is evidence for increased type-2 cytokines, microglia activation, M2A polarization, and increased levels of growth factors. In neurons, these growth factors drive a signal transduction pathway that leads to activation of the enzyme mammalian Target of Rapamycin (mTOR, and thereby to the inhibition of autophagy. Activation of mTOR is an effect that is also common to several of the genetic forms of autism. In the central nervous system, redundant synapses are removed via an autophagic process. Activation of mTOR would diminish the pruning of redundant synapses, which in the context of ASD is likely to be undesired. Based on this line of reasoning, atopic diseases like food allergy, eczema or asthma would represent risk factors for autism spectrum disorders.

  8. FimH adhesin of Escherichia coli K1 type 1 fimbriae activates BV-2 microglia

    International Nuclear Information System (INIS)

    Lee, Jongseok; Shin, Sooan; Teng, C.-H.; Hong, Suk Jin; Kim, Kwang Sik

    2005-01-01

    The generation of intense inflammation in the subarachnoid space in response to meningitis-causing bacteria contributes to brain dysfunction and neuronal injury in bacterial meningitis. Microglia, the major immune effector cells in the central nervous system (CNS), become activated by bacterial components to produce proinflammatory immune mediators. In this study, we showed that FimH adhesin, a tip component of type 1 fimbriae of meningitis-causing Escherichia coli K1, activated the murine microglial cell line, BV-2, which resulted in the production of nitric oxide and the release of tumor necrosis factor-α. Mitogen-activated protein kinases, ERK and p-38, and nuclear factor-κB were involved in FimH adhesin-mediated microglial activation. These findings suggest that FimH adhesin contributes to the CNS inflammatory response by virtue of activating microglia in E. coli meningitis

  9. Neuroinflammation and depression: microglia activation, extracellular microvesicles and microRNA dysregulation

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    Dora eBrites

    2015-12-01

    Full Text Available Patients with chronic inflammation are often associated with the emergence of depression symptoms, while diagnosed depressed patients show increased levels of circulating cytokines. Further studies revealed the activation of the brain immune cell microglia in depressed patients with a greater magnitude in individuals that committed suicide, indicating a crucial role for neuroinflammation in depression brain pathogenesis. Rapid advances in the understanding of microglial and astrocytic neurobiology were obtained in the past fifteen to twenty years. Indeed, recent data reveal that microglia play an important role in managing neuronal cell death, neurogenesis, and synaptic interactions, besides their involvement in immune-response generating cytokines. The communication between microglia and neurons is essential to synchronize these diverse functions with brain activity. Evidence is accumulating that secreted extracellular vesicles (EVs, comprising ectosomes and exosomes with a size ranging from 0.1 to 1 μm, are key players in intercellular signaling. These EVs may carry specific proteins, mRNAs and microRNAs (miRNAs. Transfer of exosomes to neurons was shown to be mediated by oligodendrocytes, microglia and astrocytes that may either be supportive to neurons, or instead disseminate the disease. Interestingly, several recent reports have identified changes in miRNAs in depressed patients, which target not only crucial pathways associated with synaptic plasticity, learning and memory but also the production of neurotrophic factors and immune cell modulation. In this article, we discuss the role of neuroinflammation in the emergence of depression, namely dynamic alterations in the status of microglia response to stimulation, and how their activation phenotypes may have an etiological role in neurodegeneneration, in particular in depressive-like behavior. We will overview the involvement of miRNAs, exosomes, ectosomes and microglia in regulating

  10. Transcriptome analysis of amoeboid and ramified microglia isolated from the corpus callosum of rat brain

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    Parakalan Rangarajan

    2012-06-01

    Full Text Available Abstract Background Microglia, the resident immune cells of the central nervous system (CNS, have two distinct phenotypes in the developing brain: amoeboid form, known to be amoeboid microglial cells (AMC and ramified form, known to be ramified microglial cells (RMC. The AMC are characterized by being proliferative, phagocytic and migratory whereas the RMC are quiescent and exhibit a slow turnover rate. The AMC transform into RMC with advancing age, and this transformation is indicative of the gradual shift in the microglial functions. Both AMC and RMC respond to CNS inflammation, and they become hypertrophic when activated by trauma, infection or neurodegenerative stimuli. The molecular mechanisms and functional significance of morphological transformation of microglia during normal development and in disease conditions is not clear. It is hypothesized that AMC and RMC are functionally regulated by a specific set of genes encoding various signaling molecules and transcription factors. Results To address this, we carried out cDNA microarray analysis using lectin-labeled AMC and RMC isolated from frozen tissue sections of the corpus callosum of 5-day and 4-week old rat brain respectively, by laser capture microdissection. The global gene expression profiles of both microglial phenotypes were compared and the differentially expressed genes in AMC and RMC were clustered based on their functional annotations. This genome wide comparative analysis identified genes that are specific to AMC and RMC. Conclusions The novel and specific molecules identified from the trancriptome explains the quiescent state functioning of microglia in its two distinct morphological states.

  11. Markers of microglia in post-mortem brain samples from patients with Alzheimer's disease: a systematic review.

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    Hopperton, K E; Mohammad, D; Trépanier, M O; Giuliano, V; Bazinet, R P

    2018-02-01

    Neuroinflammation is proposed as one of the mechanisms by which Alzheimer's disease pathology, including amyloid-β plaques, leads to neuronal death and dysfunction. Increases in the expression of markers of microglia, the main neuroinmmune cell, are widely reported in brains from patients with Alzheimer's disease, but the literature has not yet been systematically reviewed to determine whether this is a consistent pathological feature. A systematic search was conducted in Medline, Embase and PsychINFO for articles published up to 23 February 2017. Papers were included if they quantitatively compared microglia markers in post-mortem brain samples from patients with Alzheimer's disease and aged controls without neurological disease. A total of 113 relevant articles were identified. Consistent increases in markers related to activation, such as major histocompatibility complex II (36/43 studies) and cluster of differentiation 68 (17/21 studies), were identified relative to nonneurological aged controls, whereas other common markers that stain both resting and activated microglia, such as ionized calcium-binding adaptor molecule 1 (10/20 studies) and cluster of differentiation 11b (2/5 studies), were not consistently elevated. Studies of ionized calcium-binding adaptor molecule 1 that used cell counts almost uniformly identified no difference relative to control, indicating that increases in activation occurred without an expansion of the total number of microglia. White matter and cerebellum appeared to be more resistant to these increases than other brain regions. Nine studies were identified that included high pathology controls, patients who remained free of dementia despite Alzheimer's disease pathology. The majority (5/9) of these studies reported higher levels of microglial markers in Alzheimer's disease relative to controls, suggesting that these increases are not solely a consequence of Alzheimer's disease pathology. These results show that increased markers

  12. Activation of Microglia by Histamine and Substance P

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    Jin Zhu

    2014-08-01

    Full Text Available Background: Activated microglia perform many of the immune effector functions typically associated with macrophages. However, the regulators involved in microglial activation are not well defined. Because microglia play a pivotal role in immune surveillance of the CNS, we studied the effect of the neuromediators histamine and substance P on microglia. Methods: The induction of microglial activation by histamine and substance P was examined using primary cultured microglia. Fluorescent images were acquired with a confocal microscope. The levels of TNF-α and IL-6 were measured with a commercial ELISA kit. Intracellular reactive oxygen species (ROS levels were determined by dichlorodihydrofluorescein oxidation. The mitochondrial membrane potential was assessed with the MitoProbe™ JC-1 assay kit. Results: We found that the neuromediators histamine and substance P were able to stimulate microglial activation and the subsequent production of ROS and proinflammatory factors TNF-α and IL-6. These effects were partially abolished by antagonists of the histamine receptors H1 and H4 and of the substance P receptors NK-1, NK-2 and NK-3. Histamine induced mitochondrial membrane depolarization in microglia. Conclusions: These results indicate that the neuromediators histamine and SP can trigger microglial activation and release of pro-inflammatory factors from microglia, thus contributing to the development of microglia-mediated inflammation in the brain.

  13. Immune priming of microglia in a DNA repair deficient model of accelerated aging

    NARCIS (Netherlands)

    Raj, D. A.; Jaarsma, D.; Brouwer, N.; Hoeijmakers, J. H. J.; Eggen, B. J. L.; Biber, K. P. H.; Boddeke, H. W. G. M.

    2012-01-01

    Ageing of brain tissue has been associated with enhanced activity and immune priming of microglia in mice, rats and primates. It is, however, not clear yet whether this age-related microglia activation is due to the intrinsic process of microglia aging or is an adapted response of microglia to the

  14. The combination of vitamins and omega-3 fatty acids has an enhanced anti-inflammatory effect on microglia

    NARCIS (Netherlands)

    Kurtys, E.; Eisel, U. L. M.; Verkuyl, J. M.; Broersen, L. M.; Dierckx, R. A. J. O.; de Vries, E. F. J.

    2016-01-01

    Neuroinflammation is a common phenomenon in the pathology of many brain diseases. In this paper we explore whether selected vitamins and fatty acids known to modulate inflammation exert an effect on microglia, the key cell type involved in neuroinflammation. Previously these nutrients have been

  15. Injury-stimulated Sonic hedgehog expression in microglia contributes to neuroinflammatory response in the MPTP model of Parkinson's disease

    International Nuclear Information System (INIS)

    Lee, Jeong Hwi; Chung, Young Cheul; Bok, Eugene; Lee, Hankyu; Huh, Sue Hee; Lee, Ji Eun; Jin, Byung Kwan; Ko, Hyuk Wan

    2017-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disorder in which dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) region are selectively destroyed. Sonic hedgehog (Shh) has been well known to play a key role in a variety of processes such as embryogenesis, cell proliferation and protection, and tissue repair during inflammation. However, the evidences for the innate role of Shh in adult brain injury are presently lacking and studies have been needed to unveil the importance of Shh in the process of neurodegeneration. Here, we investigated the role of Shh in the pathologic progress of Parkinson's disease in MPTP-induced animal model system. Interestingly, we observed that Shh expression was gradually increased in MPTP affected SNpc region. Activated microglia exclusively expressed SHH in vivo and we could recapitulate Shh induction in activated cultured primary microglia cells. Using the SHH responsive Cre-loxP binary genetic reporter transgenic mouse system, we also found that most of the cell types except for oligodendrocyte in the SNpc region reacted to the SHH by MPTP injection. Taken together, activated microglia induced Shh expression and most neural cells except oligodendrocyte responded to microglia-derived SHH in MPTP-treated SN. These results suggest that SHH in activated microglia by MPTP-injection might be involved in the innate processes of recovery from neurotoxin induced injury in the PD animal model system. - Highlights: • Sonic hedgehog (Shh) was induced by MPTP neurotoxin at the Substantia Nigra (SN) in vivo. • Activated microglia are major cell type for SHH expression in vivo and in vitro. • Different types of cells in the brain, except oligodendrocyte, respond to microglia-derived SHH in SN region.

  16. Rod-like microglia are restricted to eyes with laser-induced ocular hypertension but absent from the microglial changes in the contralateral untreated eye.

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    Rosa de Hoz

    Full Text Available In the mouse model of unilateral laser-induced ocular hypertension (OHT the microglia in both the treated and the normotensive untreated contralateral eye have morphological signs of activation and up-regulation of MHC-II expression in comparison with naïve. In the brain, rod-like microglia align to less-injured neurons in an effort to limit damage. We investigate whether: i microglial activation is secondary to laser injury or to a higher IOP and; ii the presence of rod-like microglia is related to OHT. Three groups of mice were used: age-matched control (naïve, n=15; and two lasered: limbal (OHT, n=15; and non-draining portion of the sclera (scleral, n=3. In the lasered animals, treated eyes as well as contralateral eyes were analysed. Retinal whole-mounts were immunostained with antibodies against, Iba-1, NF-200, MHC-II, CD86, CD68 and Ym1. In the scleral group (normal ocular pressure no microglial signs of activation were found. Similarly to naïve eyes, OHT-eyes and their contralateral eyes had ramified microglia in the nerve-fibre layer related to the blood vessel. However, only eyes with OHT had rod-like microglia that aligned end-to-end, coupling to form trains of multiple cells running parallel to axons in the retinal surface. Rod-like microglia were CD68+ and were related to retinal ganglion cells (RGCs showing signs of degeneration (NF-200+RGCs. Although MHC-II expression was up-regulated in the microglia of the NFL both in OHT-eyes and their contralateral eyes, no expression of CD86 and Ym1 was detected in ramified or in rod-like microglia. After 15 days of unilateral lasering of the limbal and the non-draining portion of the sclera, activated microglia was restricted to OHT-eyes and their contralateral eyes. However, rod-like microglia were restricted to eyes with OHT and degenerated NF-200+RGCs and were absent from their contralateral eyes. Thus, rod-like microglia seem be related to the neurodegeneration associated with HTO.

  17. Intermittent hypoxia reduces microglia proliferation and induces DNA damage in vitro

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    Song Liu

    2016-05-01

    Full Text Available Objective(s:Intermittent hypoxia (IH, caused by obstructive sleep apnea (OSA, could cause hippocampus or neuron damage through multiple signaling pathways, while the underlying mechanisms are still unclear. Thus, the present study aimed to explore the effect of IH on the biological functions of microglia cells. Materials and Methods:Cell proliferation of BV2 cells after exposure to IH were observed by MTT assay and then DNA damage was detected by comet assay. RNA-sequencing assay was performed in cells under IH condition and normal conditions to find out the differentially expressed genes, which were further confirmed by reverse transcriptase polymerase chain reaction (RT-PCR and Western blot assay. Results:As results, IH inhibited the proliferation of BV2 cells, as well as caused DNA damage. RNA-sequencing assay revealed 4 differentially expressed genes (p21, Cyclin D1, Cyclin E2, and Gadd45α which were associated with the network of P53 signaling pathways in BV2 cells, among which, p21 and Gadd45α were dramatically increased while Cyclin D1 and Cyclin E2 were both decreased significantly. Moreover, inflammatory factors including IL-6, TNF-α and iNOS were significantly up-regulated in microglia cells under IH conditions for 8 hr. Conclusion:Our results indicated that IH could inhibit cyclin D1 and cyclin E2 expression via initiating multiple P53 pathways, which further blocked cell cycle transition and attenuated proliferative capability of BV2 cells. Meanwhile, IH activated inflammation reactions in BV2 cells. Present study elaborate the effects of IH on biological functions of microglia and provide theoretical foundation for further study on new therapy methods for OSA.

  18. Toll-like receptor 4 mediates microglial activation and production of inflammatory mediators in neonatal rat brain following hypoxia: role of TLR4 in hypoxic microglia

    Science.gov (United States)

    2013-01-01

    Background Hypoxia induces microglial activation which causes damage to the developing brain. Microglia derived inflammatory mediators may contribute to this process. Toll-like receptor 4 (TLR4) has been reported to induce microglial activation and cytokines production in brain injuries; however, its role in hypoxic injury remains uncertain. We investigate here TLR4 expression and its roles in neuroinflammation in neonatal rats following hypoxic injury. Methods One day old Wistar rats were subjected to hypoxia for 2 h. Primary cultured microglia and BV-2 cells were subjected to hypoxia for different durations. TLR4 expression in microglia was determined by RT-PCR, western blot and immunofluorescence staining. Small interfering RNA (siRNA) transfection and antibody neutralization were employed to downregulate TLR4 in BV-2 and primary culture. mRNA and protein expression of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) was assessed. Reactive oxygen species (ROS), nitric oxide (NO) and NF-κB levels were determined by flow cytometry, colorimetric and ELISA assays respectively. Hypoxia-inducible factor-1 alpha (HIF-1α) mRNA and protein expression was quantified and where necessary, the protein expression was depleted by antibody neutralization. In vivo inhibition of TLR4 with CLI-095 injection was carried out followed by investigation of inflammatory mediators expression via double immunofluorescence staining. Results TLR4 immunofluorescence and protein expression in the corpus callosum and cerebellum in neonatal microglia were markedly enhanced post-hypoxia. In vitro, TLR4 protein expression was significantly increased in both primary microglia and BV-2 cells post-hypoxia. TLR4 neutralization in primary cultured microglia attenuated the hypoxia-induced expression of TNF-α, IL-1β and iNOS. siRNA knockdown of TLR4 reduced hypoxia-induced upregulation of TNF-α, IL-1β, iNOS, ROS and NO in BV-2 cells. TLR4

  19. Cyclic AMP is a key regulator of M1 to M2a phenotypic conversion of microglia in the presence of Th2 cytokines.

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    Ghosh, Mousumi; Xu, Yong; Pearse, Damien D

    2016-01-13

    Microglia and macrophages play a central role in neuroinflammation. Pro-inflammatory cytokines trigger their conversion to a classically activated (M1) phenotype, sustaining inflammation and producing a cytotoxic environment. Conversely, anti-inflammatory cytokines polarize the cells towards an alternatively activated (M2), tissue reparative phenotype. Elucidation of the signal transduction pathways involved in M1 to M2 phenotypic conversion may provide insight into how the innate immune response can be harnessed during distinct phases of disease or injury to mediate neuroprotection and neurorepair. Microglial cells (cell line and primary) were subjected to combined cyclic adenosine monophosphate (cyclic AMP) and IL-4, or either alone, in the presence of pro-inflammatory mediators, lipopolysaccharide (LPS), or tumor necrosis factor-α (TNF-α). Their effects on the expression of characteristic markers for M1 and M2 microglia were assessed. Similarly, the M1 and M2 phenotypes of microglia and macrophages within the lesion site were then evaluated following a contusive spinal cord injury (SCI) to the thoracic (T8) spinal cord of rats and mice when the agents were administered systemically. It was demonstrated that cyclic AMP functions synergistically with IL-4 to promote M1 to M2 conversion of microglia in culture. The combination of cyclic AMP and IL-4, but neither alone, induced an Arg-1(+)/iNOS(-)cell phenotype with concomitant expression of other M2-specific markers including TG2 and RELM-α. M2-converted microglia showed ameliorated production of pro-inflammatory cytokines (TNF-α and IP-10) and reactive oxygen species, with no alteration in phagocytic properties. M2a conversion required protein kinase A (PKA), but not the exchange protein directly activated by cyclic AMP (EPAC). Systemic delivery of cyclic AMP and IL-4 after experimental SCI also promoted a significant M1 to M2a phenotypic change in microglia and macrophage population dynamics in the lesion

  20. Protective roles for potassium SK/KCa2 channels in microglia and neurons

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    Amalia M Dolga

    2012-11-01

    Full Text Available New concepts on potassium channel function in neuroinflammation suggest that they regulate mechanisms of microglial activation, including intracellular calcium homeostasis, morphological alterations, pro-inflammatory cytokine release, antigen presentation, and phagocytosis. Although little is known about voltage independent potassium channels in microglia, special attention emerges on small (SK/KCNN1-3/KCa2 and intermediate (IK/KCNN4/KCa3.1-conductance calcium-activated potassium channels as regulators of microglial activation in the field of research on neuroinflammation and neurodegeneration. In particular, recent findings suggested that SK/KCa2 channels, by regulating calcium homeostasis, may elicit a dual mechanism of action with protective properties in neurons and inhibition of inflammatory responses in microglia. Thus, modulating SK/KCa2 channels and calcium signaling may provide novel therapeutic strategies in neurological disorders, where neuronal cell death and inflammatory responses concomitantly contribute to disease progression. Here, we review the particular role of SK/KCa2 channels for [Ca2+]i regulation in microglia and neurons, and we discuss the potential impact for further experimental approaches addressing novel therapeutic strategies in neurological diseases, where neuronal cell death and neuroinflammatory processes are prominent.

  1. Behavioral stress alters corticolimbic microglia in a sex- and brain region-specific manner.

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    Bollinger, Justin L; Collins, Kaitlyn E; Patel, Rushi; Wellman, Cara L

    2017-01-01

    Women are more susceptible to numerous stress-linked psychological disorders (e.g., depression) characterized by dysfunction of corticolimbic brain regions critical for emotion regulation and cognitive function. Although sparsely investigated, a number of studies indicate sex differences in stress effects on neuronal structure, function, and behaviors associated with these regions. We recently demonstrated a basal sex difference in- and differential effects of stress on- microglial activation in medial prefrontal cortex (mPFC). The resident immune cells of the brain, microglia are implicated in synaptic and dendritic plasticity, and cognitive-behavioral function. Here, we examined the effects of acute (3h/day, 1 day) and chronic (3h/day, 10 days) restraint stress on microglial density and morphology, as well as immune factor expression in orbitofrontal cortex (OFC), basolateral amygdala (BLA), and dorsal hippocampus (DHC) in male and female rats. Microglia were visualized, classified based on their morphology, and stereologically counted. Microglia-associated transcripts (CD40, iNOS, Arg1, CX3CL1, CX3CR1, CD200, and CD200R) were assessed in brain punches from each region. Expression of genes linked with cellular stress, neuroimmune state, and neuron-microglia communication varied between unstressed male and female rats in a region-specific manner. In OFC, chronic stress upregulated a wider variety of immune factors in females than in males. Acute stress increased microglia-associated transcripts in BLA in males, whereas chronic stress altered immune factor expression in BLA more broadly in females. In DHC, chronic stress increased immune factor expression in males but not females. Moreover, acute and chronic stress differentially affected microglial morphological activation state in male and female rats across all brain regions investigated. In males, chronic stress altered microglial activation in a pattern consistent with microglial involvement in stress

  2. Behavioral stress alters corticolimbic microglia in a sex- and brain region-specific manner

    Science.gov (United States)

    Bollinger, Justin L.; Collins, Kaitlyn E.; Patel, Rushi

    2017-01-01

    Women are more susceptible to numerous stress-linked psychological disorders (e.g., depression) characterized by dysfunction of corticolimbic brain regions critical for emotion regulation and cognitive function. Although sparsely investigated, a number of studies indicate sex differences in stress effects on neuronal structure, function, and behaviors associated with these regions. We recently demonstrated a basal sex difference in- and differential effects of stress on- microglial activation in medial prefrontal cortex (mPFC). The resident immune cells of the brain, microglia are implicated in synaptic and dendritic plasticity, and cognitive-behavioral function. Here, we examined the effects of acute (3h/day, 1 day) and chronic (3h/day, 10 days) restraint stress on microglial density and morphology, as well as immune factor expression in orbitofrontal cortex (OFC), basolateral amygdala (BLA), and dorsal hippocampus (DHC) in male and female rats. Microglia were visualized, classified based on their morphology, and stereologically counted. Microglia-associated transcripts (CD40, iNOS, Arg1, CX3CL1, CX3CR1, CD200, and CD200R) were assessed in brain punches from each region. Expression of genes linked with cellular stress, neuroimmune state, and neuron-microglia communication varied between unstressed male and female rats in a region-specific manner. In OFC, chronic stress upregulated a wider variety of immune factors in females than in males. Acute stress increased microglia-associated transcripts in BLA in males, whereas chronic stress altered immune factor expression in BLA more broadly in females. In DHC, chronic stress increased immune factor expression in males but not females. Moreover, acute and chronic stress differentially affected microglial morphological activation state in male and female rats across all brain regions investigated. In males, chronic stress altered microglial activation in a pattern consistent with microglial involvement in stress

  3. Anti-inflammatory effects of progesterone in lipopolysaccharide-stimulated BV-2 microglia.

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    Beilei Lei

    Full Text Available Female sex is associated with improved outcome in experimental brain injury models, such as traumatic brain injury, ischemic stroke, and intracerebral hemorrhage. This implies female gonadal steroids may be neuroprotective. A mechanism for this may involve modulation of post-injury neuroinflammation. As the resident immunomodulatory cells in central nervous system, microglia are activated during acute brain injury and produce inflammatory mediators which contribute to secondary injury including proinflammatory cytokines, and nitric oxide (NO and prostaglandin E2 (PGE2, mediated by inducible NO synthase (iNOS and cyclooxygenase-2 (COX-2, respectively. We hypothesized that female gonadal steroids reduce microglia mediated neuroinflammation. In this study, the progesterone's effects on tumor necrosis factor alpha (TNF-α, iNOS, and COX-2 expression were investigated in lipopolysaccharide (LPS-stimulated BV-2 microglia. Further, investigation included nuclear factor kappa B (NF-κB and mitogen activated protein kinase (MAPK pathways. LPS (30 ng/ml upregulated TNF-α, iNOS, and COX-2 protein expression in BV-2 cells. Progesterone pretreatment attenuated LPS-stimulated TNF-α, iNOS, and COX-2 expression in a dose-dependent fashion. Progesterone suppressed LPS-induced NF-κB activation by decreasing inhibitory κBα and NF-κB p65 phosphorylation and p65 nuclear translocation. Progesterone decreased LPS-mediated phosphorylation of p38, c-Jun N-terminal kinase and extracellular regulated kinase MAPKs. These progesterone effects were inhibited by its antagonist mifepristone. In conclusion, progesterone exhibits pleiotropic anti-inflammatory effects in LPS-stimulated BV-2 microglia by down-regulating proinflammatory mediators corresponding to suppression of NF-κB and MAPK activation. This suggests progesterone may be used as a potential neurotherapeutic to treat inflammatory components of acute brain injury.

  4. Minocycline Modulates Human Social Decision-Making: Possible Impact of Microglia on Personality-Oriented Social Behaviors

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    Tsuboi, Sho; Ishikawa, Katsuhiko; Hashiya, Kazuhide; Monji, Akira; Utsumi, Hideo; Kanba, Shigenobu

    2012-01-01

    Background Microglia, one of the glial cells, play important roles in various brain pathologies including psychiatric disorders. In addition, microglia have recently been proved to monitor synaptic reactions via direct-touching even in normal brain. Human microglia may modulate various social/mental functions, while microglial social/mental roles remain unresolved especially in healthy humans. There is no known drug with the specific effect of modulating microglia. Therefore, using minocycline, a tetracycline antibiotic and the most famous microglial inhibitor, is one of the best alternative approaches to clarify microglial functions on human social/mental activities. Methodology/Principal Findings We conducted a double-blind randomized trial of trust game, a monetary decision-making experiment, with ninety-nine human adult males who decided how much to trust an anonymous partner after a four-day administration of minocycline. Our previous pilot trial indicated a positive effect of minocycline, while the underlying mechanisms were not clarified. Therefore, in this trial with larger samples, we additionally measured the effects of anxiety and personality. The monetary score in trust game was significantly lower in the minocycline group. Interestingly, participants’ ways of decision-making were significantly shifted; cooperativeness, one component of personality, proved to be the main modulating factor of decision-making in the placebo group, on the other hand, the minocycline group was mainly modulated by state anxiety and trustworthiness. Conclusions/Significance Our results suggest that minocycline led to more situation-oriented decision-making, possibly by suppressing the effects of personality traits, and furthermore that personality and social behaviors might be modulated by microglia. Early-life events may activate human microglia, establish a certain neuro-synaptic connection, and this formation may determine each human’s personality and personality

  5. Neuroserpin Protects Rat Neurons and Microglia-Mediated Inflammatory Response Against Oxygen-Glucose Deprivation- and Reoxygenation Treatments in an In Vitro Study

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    Xuelian Yang

    2016-04-01

    Full Text Available Background/Aims: Neuroserpin (NSP is known for its neuroprotective role in cerebral ischemic animal models and patients. Our laboratory conducted a series of investigations on the neuroprotection of NSP in different cells in the brain. In the present study, we further observe the effects of NSP on neurons and microglia-mediated inflammatory response following oxygen-glucose deprivation (OGD, and explore possible mechanisms related to neuroprotection of OGD in the central nervous system (CNS. Methods: Neurons and microglia from neonatal rats were treated with OGD followed by reoxygenation (OGD/R. To confirm the effects of NSP, the neuronal survival, neuronal apoptosis, and lactate dehydrogenase (LDH release were measured in cultured neurons. Furthermore, the levels of IL-1β and nitric oxide (NO release were also detected in cultured microglia. The possible mechanisms for the neuroprotective effect of NSP were explored using Western blot analysis. Results: NSP administration can reverse abnormal variations in neurons and microglia-mediated inflammatory response induced by OGD/R processes. The neuronal survival rate, neuronal apoptosis rate, and LDH release were significantly improved by NSP administration in neurons. Simultaneously, the release of IL-1β and NO were significantly reduced by NSP in microglia. Western blot showed that the expression of ERK, P38, and JNK was upregulated in microglia by the OGD/R treatment, and these effects were significantly inhibited by NSP. Conclusion: These data verified the neuroprotective effects of NSP on neurons and microglia-mediated inflammatory response. Inhibition of the mitogen-activated protein kinase (MAPK signaling pathways might play a potential role in NSP neuroprotection on microglia-mediated inflammatory response, which needs further verification.

  6. Identification of Glial Activation Markers by Comparison of Transcriptome Changes between Astrocytes and Microglia following Innate Immune Stimulation.

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    Madeddu, Silvia; Woods, Tyson A; Mukherjee, Piyali; Sturdevant, Dan; Butchi, Niranjan B; Peterson, Karin E

    2015-01-01

    The activation of astrocytes and microglia is often associated with diseases of the central nervous system (CNS). Understanding how activation alters the transcriptome of these cells may offer valuable insight regarding how activation of these cells mediate neurological damage. Furthermore, identifying common and unique pathways of gene expression during activation may provide new insight into the distinct roles these cells have in the CNS during infection and inflammation. Since recent studies indicate that TLR7 recognizes not only viral RNA but also microRNAs that are released by damaged neurons and elevated during neurological diseases, we first examined the response of glial cells to TLR7 stimulation using microarray analysis. Microglia were found to generate a much stronger response to TLR7 activation than astrocytes, both in the number of genes induced as well as fold induction. Although the primary pathways induced by both cell types were directly linked to immune responses, microglia also induced pathways associated with cellular proliferation, while astrocytes did not. Targeted analysis of a subset of the upregulated genes identified unique mRNA, including Ifi202b which was only upregulated by microglia and was found to be induced during both retroviral and bunyavirus infections in the CNS. In addition, other genes including Birc3 and Gpr84 as well as two expressed sequences AW112010 and BC023105 were found to be induced in both microglia and astrocytes and were upregulated in the CNS following virus infection. Thus, expression of these genes may a useful measurement of glial activation during insult or injury to the CNS.

  7. Identification of Glial Activation Markers by Comparison of Transcriptome Changes between Astrocytes and Microglia following Innate Immune Stimulation.

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    Silvia Madeddu

    Full Text Available The activation of astrocytes and microglia is often associated with diseases of the central nervous system (CNS. Understanding how activation alters the transcriptome of these cells may offer valuable insight regarding how activation of these cells mediate neurological damage. Furthermore, identifying common and unique pathways of gene expression during activation may provide new insight into the distinct roles these cells have in the CNS during infection and inflammation. Since recent studies indicate that TLR7 recognizes not only viral RNA but also microRNAs that are released by damaged neurons and elevated during neurological diseases, we first examined the response of glial cells to TLR7 stimulation using microarray analysis. Microglia were found to generate a much stronger response to TLR7 activation than astrocytes, both in the number of genes induced as well as fold induction. Although the primary pathways induced by both cell types were directly linked to immune responses, microglia also induced pathways associated with cellular proliferation, while astrocytes did not. Targeted analysis of a subset of the upregulated genes identified unique mRNA, including Ifi202b which was only upregulated by microglia and was found to be induced during both retroviral and bunyavirus infections in the CNS. In addition, other genes including Birc3 and Gpr84 as well as two expressed sequences AW112010 and BC023105 were found to be induced in both microglia and astrocytes and were upregulated in the CNS following virus infection. Thus, expression of these genes may a useful measurement of glial activation during insult or injury to the CNS.

  8. Intermittent hypoxia from obstructive sleep apnea may cause neuronal impairment and dysfunction in central nervous system: the potential roles played by microglia

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    Yang Q

    2013-08-01

    Full Text Available Qingchan Yang,1,* Yan Wang,2,* Jing Feng,2 Jie Cao,2 Baoyuan Chen2 1Graduate School of Tianjin Medical University, 2Respiratory Department, Tianjin Medical University General Hospital, Tianjin, People's Republic of China *These authors contributed equally to this work Abstract: Obstructive sleep apnea (OSA is a common condition characterized by repetitive episodes of complete (apnea or partial (hypopnea obstruction of the upper airway during sleep, resulting in oxygen desaturation and arousal from sleep. Intermittent hypoxia (IH resulting from OSA may cause structural neuron damage and dysfunction in the central nervous system (CNS. Clinically, it manifests as neurocognitive and behavioral deficits with oxidative stress and inflammatory impairment as its pathophysiological basis, which are mediated by microglia at the cellular level. Microglia are dominant proinflammatory cells in the CNS. They induce CNS oxidative stress and inflammation, mainly through mitochondria, reduced nicotinamide adenine dinucleotide phosphate oxidase, and the release of excitatory toxic neurotransmitters. The balance between neurotoxic versus protective and anti- versus proinflammatory microglial factors might determine the final roles of microglia after IH exposure from OSA. Microglia inflammatory impairments will continue and cascade persistently upon activation, ultimately resulting in clinically significant neuron damage and dysfunction in the CNS. In this review article, we summarize the mechanisms of structural neuron damage in the CNS and its concomitant dysfunction due to IH from OSA, and the potential roles played by microglia in this process. Keywords: intermittent hypoxia, obstructive sleep apnea, microglia, inflammation, apoptosis

  9. Microglia acquire distinct activation profiles depending on the degree of alpha-synuclein neuropathology in a rAAV based model of Parkinson's disease.

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    Vanesa Sanchez-Guajardo

    Full Text Available Post-mortem analysis of brains from Parkinson's disease (PD patients strongly supports microglia activation and adaptive immunity as factors contributing to disease progression. Such responses may be triggered by alpha-synuclein (alpha-syn, which is known to be the main constituent of the aggregated proteins found in Lewy bodies in the brains of PD patients. To investigate this we used a recombinant viral vector to express human alpha-syn in rat midbrain at levels that induced neuronal pathology either in the absence or the presence of dopaminergic cell death, thereby mimicking early or late stages of the disease. Microglia activation was assessed by stereological quantification of Mac1+ cells, as well as the expression patterns of CD68 and MCH II. In our study, when alpha-syn induced neuronal pathology but not cell death, a fast transient increase in microglia cell numbers resulted in the long-term induction of MHC II+ microglia, denoting antigen-presenting ability. On the other hand, when alpha-syn induced both neuronal pathology and cell death, there was a delayed increase in microglia cell numbers, which correlated with long-lasting CD68 expression and a morphology reminiscent of peripheral macrophages. In addition T-lymphocyte infiltration, as judged by the presence of CD4+ and CD8+ cells, showed distinct kinetics depending on the degree of neurodegeneration, and was significantly higher when cell death occurred. We have thus for the first time shown that the microglial response differs depending on whether alpha-syn expression results on cell death or not, suggesting that microglia may play different roles during disease progression. Furthermore, our data suggest that the microglial response is modulated by early events related to alpha-syn expression in substantia nigra and persists at the long term.

  10. Chronic methamphetamine exposure significantly decreases microglia activation in the arcuate nucleus.

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    Lloyd, Steven A; Corkill, Beau; Bruster, Matthew C; Roberts, Rick L; Shanks, Ryan A

    2017-07-01

    Methamphetamine is a powerful psychostimulant drug and its use and abuse necessitates a better understanding of its neurobiobehavioral effects. The acute effects of binge dosing of methamphetamine on the neurons in the CNS are well studied. However, the long-term effects of chronic, low-dose methamphetamine are less well characterized, especially in other cell types and areas outside of the major dopamine pathways. Mice were administered 5mg/kg/day methamphetamine for ten days and brain tissue was analyzed using histochemistry and image analysis. Increased microglia activity in the striatum confirmed toxic effects of methamphetamine in this brain region using this dosing paradigm. A significant decrease in microglia activity in the arcuate nucleus of the hypothalamus was observed with no effect noted on dopamine neurons in the arcuate nucleus. Given the importance of this area in homeostatic and neuroendocrine regulation, the current study highlights the need to more fully understand the systemic effects of chronic, low-dose methamphetamine use. The novel finding of microglia downregulation after chronic methamphetamine could lead to advances in understanding neuroinflammatory responses towards addiction treatment and protection from psychostimulant-induced neurotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. [Ultrastructural pathology of oligodendrocytes in the white matter in continuous paranoid schizophrenia: a role for microglia].

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    Uranova, N A; Vikhreva, O V; Rakhmanova, V I; Orlovskaya, D D

    Previously the authors have reported the ultrastructural pathology and deficit of oligodendrocytes in gray and white matter of the prefrontal cortex in schizophrenia. The aim of the study was to determine of the effects of microglia on the ultrastructure of oligodendrocytes in the white matter underlying the prefrontal cortex in continuous schizophrenia. Postmortem morphometric electron microscopic study of oligodendrocytes in close apposition to microglia was performed in white matter underlying the prefrontal cortex (BA10). Eleven cases of chronic continuous schizophrenia and 11 normal controls were studied. Areas of oligodendrocytes, of their nuclei and cytoplasm, volume density (Vv) and the number of mitochondria, vacuoles of endoplasmic reticulum and lipofuscin granules were estimated. Group comparison was performed using ANCOVA. The schizophrenia group differed from the control group by paucity of ribosomes in the cytoplasm of oligodendrocytes, a significant decrease in Vv and the number of mitochondria and increase in the number of lipofuscin granules. Significant correlations between the parameters of lipofuscin granules, mitochondria and vacuoles were found only in the schizophrenia group. The number of lipofuscin granules were correlated positively with the illness duration. Dystrophic alterations of oligodendrocytes attached to microglial cells were found in the white matter of the prefrontal cortex in chronic paranoid schizophrenia as compared to controls. The data obtained suggest that microglia might contribute to abnormalities of energy, lipid and protein metabolism of oligodendrocytes in schizophrenia.

  12. Sensing of HSV-1 by the cGAS-STING pathway in microglia orchestrates antiviral defence in the CNS

    DEFF Research Database (Denmark)

    Reinert, Line S; Lopušná, Katarína; Winther, Henriette

    2016-01-01

    Herpes simplex encephalitis (HSE) is the most common form of acute viral encephalitis in industrialized countries. Type I interferon (IFN) is important for control of herpes simplex virus (HSV-1) in the central nervous system (CNS). Here we show that microglia are the main source of HSV-induced t......Herpes simplex encephalitis (HSE) is the most common form of acute viral encephalitis in industrialized countries. Type I interferon (IFN) is important for control of herpes simplex virus (HSV-1) in the central nervous system (CNS). Here we show that microglia are the main source of HSV......-induced type I IFN expression in CNS cells and these cytokines are induced in a cGAS-STING-dependent manner. Consistently, mice defective in cGAS or STING are highly susceptible to acute HSE. Although STING is redundant for cell-autonomous antiviral resistance in astrocytes and neurons, viral replication...... is strongly increased in neurons in STING-deficient mice. Interestingly, HSV-infected microglia confer STING-dependent antiviral activities in neurons and prime type I IFN production in astrocytes through the TLR3 pathway. Thus, sensing of HSV-1 infection in the CNS by microglia through the cGAS-STING pathway...

  13. Blockade of NMDA receptors decreased spinal microglia activation in bee venom induced acute inflammatory pain in rats.

    Science.gov (United States)

    Li, Li; Wu, Yongfang; Bai, Zhifeng; Hu, Yuyan; Li, Wenbin

    2017-03-01

    Microglial cells in spinal dorsal horn can be activated by nociceptive stimuli and the activated microglial cells release various cytokines enhancing the nociceptive transmission. However, the mechanisms underlying the activation of spinal microglia during nociceptive stimuli have not been well understood. In order to define the role of NMDA receptors in the activation of spinal microglia during nociceptive stimuli, the present study was undertaken to investigate the effect of blockade of NMDA receptors on the spinal microglial activation induced by acute peripheral inflammatory pain in rats. The acute inflammatory pain was induced by subcutaneous bee venom injection to the plantar surface of hind paw of rats. Spontaneous pain behavior, thermal withdrawal latency and mechanical withdrawal threshold were rated. The expression of specific microglia marker CD11b/c was assayed by immunohistochemistry and western blot. After bee venom treatment, it was found that rats produced a monophasic nociception characterized by constantly lifting and licking the injected hind paws, decreased thermal withdrawal latency and mechanical withdrawal threshold; immunohistochemistry displayed microglia with enlarged cell bodies, thickened, extended cellular processes with few ramifications, small spines, and intensive immunostaining; western blot showed upregulated expression level of CD11b/c within the period of hyperalgesia. Prior intrathecal injection of MK-801, a selective antagonist of NMDA receptors, attenuated the pain behaviors and suppressed up-regulation of CD11b/c induced by bee venom. It can be concluded that NMDA receptors take part in the mediation of spinal microglia activation in bee venom induced peripheral inflammatory pain and hyperalgesia in rats.

  14. Role of microglia in neuropathic pain, postoperative pain, and morphine tolerance

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    Wen, Yeong-Ray; Tan, Ping-Heng; Cheng, Jen-Kun; Liu, Yen-Chin; Ji, Ru-Rong

    2011-01-01

    Management of chronic pain such as nerve injury-induced neuropathic pain associated with diabetic neuropathy, viral infection, and cancer is a real clinical challenge. Major surgeries such as breast and thoracic surgery, leg amputation, and coronary artery bypass surgery also lead to chronic pain in 10–50% of individuals after acute postoperative pain, in part due to surgery-induced nerve injury. Current treatments mainly focus on blocking neurotransmission in the pain pathway and have only resulted in limited success. Ironically, chronic opioid exposure may lead to paradoxical pain. Development of effective therapeutic strategies requires a better understanding of cellular mechanisms underlying the pathogenesis of neuropathic pain. An important progress in pain research points to important role of microglial cells in the development of chronic pain. Spinal cord microglia are strongly activated after nerve injury, surgical incision, and chronic opioid exposure. Increasing evidence suggests that under all these conditions the activated microglia not only exhibit increased expression of microglial markers CD11b and Iba1 but also display elevated phosphorylation of p38 MAP kinase. Inhibition of spinal cord p38 has been shown to attenuate neuropathic pain and postoperative pain, as well as morphine-induced antinociceptive tolerance. Activation of p38 in spinal microglia results in increased synthesis and release of the neurotrophin BDNF and the proinflammatory cytokines IL-1β, IL-6, and TNF-α. These microglia-released mediators can powerfully modulate spinal cord synaptic transmission, leading to increased excitability of dorsal horn neurons, i.e. central sensitization, in part via suppressing inhibitory synaptic transmission. We review the studies that support the pronociceptive role of microglia in conditions of neuropathic pain, post-surgical pain, and opioid tolerance. Some of these studies have been accomplished by four Taiwanese anesthesiologists who are also

  15. The spider effect: morphological and orienting classification of microglia in response to stimuli in vivo.

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    Rahul A Jonas

    Full Text Available The different morphological stages of microglial activation have not yet been described in detail. We transected the olfactory bulb of rats and examined the activation of the microglial system histologically. Six stages of bidirectional microglial activation (A and deactivation (R were observed: from stage 1A to 6A, the cell body size increased, the cell process number decreased, and the cell processes retracted and thickened, orienting toward the direction of the injury site; until stage 6A, when all processes disappeared. In contrast, in deactivation stages 6R to 1R, the microglia returned to the original site exhibiting a stepwise retransformation to the original morphology. Thin highly branched processes re-formed in stage 1R, similar to those in stage 1A. This reverse transformation mirrored the forward transformation except in stages 6R to 1R: cells showed multiple nuclei which were slowly absorbed. Our findings support a morphologically defined stepwise activation and deactivation of microglia cells.

  16. Contribution of TRPV1 to microglia-derived IL-6 and NFkappaB translocation with elevated hydrostatic pressure.

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    Sappington, Rebecca M; Calkins, David J

    2008-07-01

    The authors investigated the contributions of the transient receptor potential vanilloid-1 receptor (TRPV1) and Ca(2+) to microglial IL-6 and nuclear factor kappa B (NFkappaB) translocation with elevated hydrostatic pressure. The authors first examined IL-6 colocalization with the microglia marker Iba-1 in the DBA/2 mouse model of glaucoma to establish relevance. They isolated microglia from rat retina and maintained them at ambient or elevated (+70 mm Hg) hydrostatic pressure in vitro and used ELISA and immunocytochemistry to measure changes in the IL-6 concentration and NFkappaB translocation induced by the Ca(2+) chelator EGTA, the broad-spectrum Ca(2+) channel inhibitor ruthenium red, and the TRPV1 antagonist iodo-resiniferatoxin (I-RTX). They applied the Ca(2+) dye Fluo-4 AM to measure changes in intracellular Ca(2+) at elevated pressure induced by I-RTX and confirmed TRPV1 expression in microglia using PCR and immunocytochemistry. In DBA/2 retina, elevated intraocular pressure increased microglial IL-6 in the ganglion cell layer. Elevated hydrostatic pressure (24 hours) increased microglial IL-6 release, cytosolic NFkappaB, and NFkappaB translocation in vitro. These effects were reduced substantially by EGTA and ruthenium red. Antagonism of TRPV1 in microglia partially inhibited pressure-induced increases in IL-6 release and NFkappaB translocation. Brief elevated pressure (1 hour) induced a significant increase in microglial intracellular Ca(2+) that was partially attenuated by TRPV1 antagonism. Elevated pressure induces an influx of extracellular Ca(2+) in retinal microglia that precedes the activation of NFkappaB and the subsequent production and release of IL-6 and is at least partially dependent on the activation of TRPV1 and other ruthenium red-sensitive channels.

  17. Contribution of microglia-mediated neuroinflammation to retinal degenerative diseases.

    Science.gov (United States)

    Madeira, Maria H; Boia, Raquel; Santos, Paulo F; Ambrósio, António F; Santiago, Ana R

    2015-01-01

    Retinal degenerative diseases are major causes of vision loss and blindness worldwide and are characterized by chronic and progressive neuronal loss. One common feature of retinal degenerative diseases and brain neurodegenerative diseases is chronic neuroinflammation. There is growing evidence that retinal microglia, as in the brain, become activated in the course of retinal degenerative diseases, having a pivotal role in the initiation and propagation of the neurodegenerative process. A better understanding of the events elicited and mediated by retinal microglia will contribute to the clarification of disease etiology and might open new avenues for potential therapeutic interventions. This review aims at giving an overview of the roles of microglia-mediated neuroinflammation in major retinal degenerative diseases like glaucoma, age-related macular degeneration, and diabetic retinopathy.

  18. Microglia in Alzheimer’s Disease: Activated, Dysfunctional or Degenerative

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    Victoria Navarro

    2018-05-01

    Full Text Available Microglial activation has been considered a crucial player in the pathological process of multiple human neurodegenerative diseases. In some of these pathologies, such as Amyotrophic Lateral Sclerosis or Multiple Sclerosis, the immune system and microglial cells (as part of the cerebral immunity play a central role. In other degenerative processes, such as Alzheimer’s disease (AD, the role of microglia is far to be elucidated. In this “mini-review” article, we briefly highlight our recent data comparing the microglial response between amyloidogenic transgenic models, such as APP/PS1 and AD patients. Since the AD pathology could display regional heterogeneity, we focus our work at the hippocampal formation. In APP based models a prominent microglial response is triggered around amyloid-beta (Aβ plaques. These strongly activated microglial cells could drive the AD pathology and, in consequence, could be implicated in the neurodegenerative process observed in models. On the contrary, the microglial response in human samples is, at least, partial or attenuated. This patent difference could simply reflect the lower and probably slower Aβ production observed in human hippocampal samples, in comparison with models, or could reflect the consequence of a chronic long-standing microglial activation. Beside this differential response, we also observed microglial degeneration in Braak V–VI individuals that, indeed, could compromise their normal role of surveying the brain environment and respond to the damage. This microglial degeneration, particularly relevant at the dentate gyrus, might be mediated by the accumulation of toxic soluble phospho-tau species. The consequences of this probably deficient immunological protection, observed in AD patients, are unknown.

  19. Pyrroloquinoline quinone (PQQ inhibits lipopolysaccharide induced inflammation in part via downregulated NF-κB and p38/JNK activation in microglial and attenuates microglia activation in lipopolysaccharide treatment mice.

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    Chongfei Yang

    Full Text Available Therapeutic strategies designed to inhibit the activation of microglia may lead to significant advancement in the treatment of most neurodegenerative diseases. Pyrroloquinoline quinone (PQQ is a naturally occurring redox cofactor that acts as an essential nutrient, antioxidant, and has been reported to exert potent immunosuppressive effects. In the present study, the anti-inflammatory effects of PQQ was investigated in LPS treated primary microglia cells. Our observations showed that pretreatment with PQQ significantly inhibited the production of NO and PGE2 and suppressed the expression of pro-inflammatory mediators such as iNOS, COX-2, TNF-a, IL-1b, IL-6, MCP-1 and MIP-1a in LPS treated primary microglia cells. The nuclear translocation of NF-κB and the phosphorylation level of p65, p38 and JNK MAP kinase pathways were also inhibited by PQQ in LPS stimulated primary microglia cells. Further a systemic LPS treatment acute inflammation murine brain model was used to study the suppressive effects of PQQ against neuroinflammation in vivo. Mice treated with PQQ demonstrated marked attenuation of neuroinflammation based on Western blotting and immunohistochemistry analysis of Iba1-against antibody in the brain tissue. Indicated that PQQ protected primary cortical neurons against microglia-mediated neurotoxicity. These results collectively suggested that PQQ might be a promising therapeutic agent for alleviating the progress of neurodegenerative diseases associated with microglia activation.

  20. Alterations in the Interplay between Neurons, Astrocytes and Microglia in the Rat Dentate Gyrus in Experimental Models of Neurodegeneration

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    Daniele Lana

    2017-09-01

    Full Text Available The hippocampus is negatively affected by aging and neurodegenerative diseases leading to impaired learning and memory abilities. A diverse series of progressive modifications in the intercellular communication among neurons, astrocytes and microglia occur in the hippocampus during aging or inflammation. A detailed understanding of the neurobiological modifications that contribute to hippocampal dysfunction may reveal new targets for therapeutic intervention. The current study focussed on the interplay between neurons and astroglia in the Granule Layer (GL and the Polymorphic Layer (PL of the Dentate Gyrus (DG of adult, aged and LPS-treated rats. In GL and PL of aged and LPS-treated rats, astrocytes were less numerous than in adult rats. In GL of LPS-treated rats, astrocytes acquired morphological features of reactive astrocytes, such as longer branches than was observed in adult rats. Total and activated microglia increased in the aged and LPS-treated rats, as compared to adult rats. In the GL of aged and LPS-treated rats many neurons were apoptotic. Neurons decreased significantly in GL and PL of aged but not in rats treated with LPS. In PL of aged and LPS-treated rats many damaged neurons were embraced by microglia cells and were infiltrated by branches of astrocyte, which appeared to be bisecting the cell body, forming triads. Reactive microglia had a scavenging activity of dying neurons, as shown by the presence of neuronal debris within their cytoplasm. The levels of the chemokine fractalkine (CX3CL1 increased in hippocampal homogenates of aged rats and rats treated with LPS, and CX3CL1 immunoreactivity colocalized with activated microglia cells. Here we demonstrated that in the DG of aged and LPS-treated rats, astrocytes and microglia cooperate and participate in phagocytosis/phagoptosis of apoptotic granular neurons. The differential expression/activation of astroglia and the alteration of their intercommunication may be responsible for

  1. Human microglia and astrocytes express cGAS-STING viral sensing components.

    Science.gov (United States)

    Jeffries, Austin M; Marriott, Ian

    2017-09-29

    While microglia and astrocytes are known to produce key inflammatory and anti-viral mediators following infection with replicative DNA viruses, the mechanisms by which these cell types perceive such threats are poorly understood. Recently, cyclic GMP-AMP synthase (cGAS) has been identified as an important cytosolic sensor for DNA viruses and retroviruses in peripheral leukocytes. Here we confirm the ability of human microglial and astrocytic cell lines and primary human glia to respond to foreign intracellular double stranded DNA. Importantly, we provide the first demonstration that human microglia and astrocytes show robust levels of cGAS protein expression at rest and following activation. Furthermore, we show these cell types also constitutively express the critical downstream cGAS adaptor protein, stimulator of interferon genes (STING). The present finding that human glia express the principle components of the cGAS-STING pathway provides a foundation for future studies to investigate the relative importance of these molecules in clinically relevant viral CNS infections. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Curcumin Delays Retinal Degeneration by Regulating Microglia Activation in the Retina of rd1 Mice.

    Science.gov (United States)

    Wang, Yanhe; Yin, Zhiyuan; Gao, Lixiong; Sun, Dayu; Hu, Xisu; Xue, Langyue; Dai, Jiaman; Zeng, YuXiao; Chen, Siyu; Pan, Boju; Chen, Min; Xie, Jing; Xu, Haiwei

    2017-01-01

    Retinitis pigmentosa (RP) is characterized by degeneration of photoreceptors, and there are currently no effective treatments for this disease. However, curcumin has shown neuroprotectant efficacy in a RP rat and swine model, and thus, may have neuroprotective effects in this disease. Immunofluorescence staining, electroretinogram recordings, and behavioral tests were used to analyze the effects of curcumin and the underlying mechanism in retinal degeneration 1 (rd1) mice. The number of apoptotic cells in the retina of rd1 mice at postnatal day 14 significantly decreased with curcumin treatment and visual function was improved. The activation of microglia and secretion of chemokines and matrix metalloproteinases in the retina were inhibited by curcumin. These effects were also observed in a co-culture of BV2 microglial cells and retina-derived 661W cells. Curcumin delayed retinal degeneration by suppressing microglia activation in the retina of rd1 mice. Thus, it may be an effective treatment for neurodegenerative disorders such as RP. © 2017 The Author(s). Published by S. Karger AG, Basel.

  3. Curcumin Delays Retinal Degeneration by Regulating Microglia Activation in the Retina of rd1 Mice

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    Yanhe Wang

    2017-11-01

    Full Text Available Background/Aims: Retinitis pigmentosa (RP is characterized by degeneration of photoreceptors, and there are currently no effective treatments for this disease. However, curcumin has shown neuroprotectant efficacy in a RP rat and swine model, and thus, may have neuroprotective effects in this disease. Methods: Immunofluorescence staining, electroretinogram recordings, and behavioral tests were used to analyze the effects of curcumin and the underlying mechanism in retinal degeneration 1 (rd1 mice. Results: The number of apoptotic cells in the retina of rd1 mice at postnatal day 14 significantly decreased with curcumin treatment and visual function was improved. The activation of microglia and secretion of chemokines and matrix metalloproteinases in the retina were inhibited by curcumin. These effects were also observed in a co-culture of BV2 microglial cells and retina-derived 661W cells. Conclusions: Curcumin delayed retinal degeneration by suppressing microglia activation in the retina of rd1 mice. Thus, it may be an effective treatment for neurodegenerative disorders such as RP.

  4. Evidence that spinal astrocytes but not microglia contribute to the pathogenesis of paclitaxel-induced painful neuropathy

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    Zhang, Haijun; Yoon, Seo-Yeon; Zhang, Hongmei; Dougherty, Patrick M.

    2012-01-01

    Paclitaxel often induces persistent painful neuropathy as its most common treatment limiting side effect. Little is known concerning the underlying mechanisms. Given the prominent role of glial cells in many types of neuropathic pain, we investigated here the morphological and functional changes of spinal astrocytes and microglia in a rat model of paclitaxel-induced neuropathy. Immunohistochemistry, western blotting and real-time polymerase chain reaction (rt-PCR) were performed with samples ...

  5. Enrichment increases hippocampal neurogenesis independent of blood monocyte-derived microglia presence following high-dose total body irradiation.

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    Ruitenberg, Marc J; Wells, Julia; Bartlett, Perry F; Harvey, Alan R; Vukovic, Jana

    2017-06-01

    Birth of new neurons in the hippocampus persists in the brain of adult mammals and critically underpins optimal learning and memory. The process of adult neurogenesis is significantly reduced following brain irradiation and this correlates with impaired cognitive function. In this study, we aimed to compare the long-term effects of two environmental paradigms (i.e. enriched environment and exercise) on adult neurogenesis following high-dose (10Gy) total body irradiation. When housed in standard (sedentary) conditions, irradiated mice revealed a long-lasting (up to 4 months) deficit in neurogenesis in the granule cell layer of the dentate gyrus, the region that harbors the neurogenic niche. This depressive effect of total body irradiation on adult neurogenesis was partially alleviated by exposure to enriched environment but not voluntary exercise, where mice were single-housed with unlimited access to a running wheel. Exposure to voluntary exercise, but not enriched environment, did lead to significant increases in microglia density in the granule cell layer of the hippocampus; our study shows that these changes result from local microglia proliferation rather than recruitment and infiltration of circulating Cx 3 cr1 +/gfp blood monocytes that subsequently differentiate into microglia-like cells. In summary, latent neural precursor cells remain present in the neurogenic niche of the adult hippocampus up to 8 weeks following high-dose total body irradiation. Environmental enrichment can partially restore the adult neurogenic process in this part of the brain following high-dose irradiation, and this was found to be independent of blood monocyte-derived microglia presence. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  6. Botanical Polyphenols Mitigate Microglial Activation and Microglia-Induced Neurotoxicity: Role of Cytosolic Phospholipase A2.

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    Chuang, Dennis Y; Simonyi, Agnes; Cui, Jiankun; Lubahn, Dennis B; Gu, Zezong; Sun, Grace Y

    2016-09-01

    Microglia play a significant role in the generation and propagation of oxidative/nitrosative stress, and are the basis of neuroinflammatory responses in the central nervous system. Upon stimulation by endotoxins such as lipopolysaccharides (LPS), these cells release pro-inflammatory factors which can exert harmful effects on surrounding neurons, leading to secondary neuronal damage and cell death. Our previous studies demonstrated the effects of botanical polyphenols to mitigate inflammatory responses induced by LPS, and highlighted an important role for cytosolic phospholipase A2 (cPLA2) upstream of the pro-inflammatory pathways (Chuang et al. in J Neuroinflammation 12(1):199, 2015. doi: 10.1186/s12974-015-0419-0 ). In this study, we investigate the action of botanical compounds and assess whether suppression of cPLA2 in microglia is involved in the neurotoxic effects on neurons. Differentiated SH-SY5Y neuroblastoma cells were used to test the neurotoxicity of conditioned medium from stimulated microglial cells, and WST-1 assay was used to assess for the cell viability of SH-SY5Y cells. Botanicals such as quercetin and honokiol (but not cyanidin-3-O-glucoside, 3CG) were effective in inhibiting LPS-induced nitric oxide (NO) production and phosphorylation of cPLA2. Conditioned medium from BV-2 cells stimulated with LPS or IFNγ caused neurotoxicity to SH-SY5Y cells. Decrease in cell viability could be ameliorated by pharmacological inhibitors for cPLA2 as well as by down-regulating cPLA2 with siRNA. Botanicals effective in inhibition of LPS-induced NO and cPLA2 phosphorylation were also effective in ameliorating microglial-induced neurotoxicity. Results demonstrated cytotoxic factors from activated microglial cells to cause damaging effects to neurons and potential use of botanical polyphenols to ameliorate the neurotoxic effects.

  7. Molecular Mechanisms Modulating the Phenotype of Macrophages and Microglia

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    Stephanie A. Amici

    2017-11-01

    Full Text Available Macrophages and microglia play crucial roles during central nervous system development, homeostasis and acute events such as infection or injury. The diverse functions of tissue macrophages and microglia are mirrored by equally diverse phenotypes. A model of inflammatory/M1 versus a resolution phase/M2 macrophages has been widely used. However, the complexity of macrophage function can only be achieved by the existence of varied, plastic and tridimensional macrophage phenotypes. Understanding how tissue macrophages integrate environmental signals via molecular programs to define pathogen/injury inflammatory responses provides an opportunity to better understand the multilayered nature of macrophages, as well as target and modulate cellular programs to control excessive inflammation. This is particularly important in MS and other neuroinflammatory diseases, where chronic inflammatory macrophage and microglial responses may contribute to pathology. Here, we perform a comprehensive review of our current understanding of how molecular pathways modulate tissue macrophage phenotype, covering both classic pathways and the emerging role of microRNAs, receptor-tyrosine kinases and metabolism in macrophage phenotype. In addition, we discuss pathway parallels in microglia, novel markers helpful in the identification of peripheral macrophages versus microglia and markers linked to their phenotype.

  8. Inhibition of nitric oxide synthase expression in activated microglia and peroxynitrite scavenging activity by Opuntia ficus indica var. saboten.

    Science.gov (United States)

    Lee, Ming Hong; Kim, Jae Yeon; Yoon, Jeong Hoon; Lim, Hyo Jin; Kim, Tae Hee; Jin, Changbae; Kwak, Wie-Jong; Han, Chang-Kyun; Ryu, Jae-Ha

    2006-09-01

    Activated microglia by neuronal injury or inflammatory stimulation overproduce nitric oxide (NO) by inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS) such as superoxide anion, resulting in neurodegenerative diseases. The toxic peroxynitrite (ONOO-), the reaction product of NO and superoxide anion further contributes to oxidative neurotoxicity. A butanol fraction obtained from 50% ethanol extracts of Opuntia ficus indica var. saboten (Cactaceae) stem (SK OFB901) and its hydrolysis product (SK OFB901H) inhibited the production of NO in LPS-activated microglia in a dose dependent manner (IC50 15.9, 4.2 microg/mL, respectively). They also suppressed the expression of protein and mRNA of iNOS in LPS-activated microglial cells at higher than 30 microg/mL as observed by western blot analysis and RT-PCR experiment. They also inhibited the degradation of I-kappaB-alpha in activated microglia. Moreover, they showed strong activity of peroxynitrite scavenging in a cell free bioassay system. These results imply that Opuntia ficus indica may have neuroprotective activity through the inhibition of NO production by activated microglial cells and peroxynitrite scavenging activity. Copyright (c) 2006 John Wiley & Sons, Ltd.

  9. Markers of microglia in post-mortem brain samples from patients with Alzheimer’s disease: a systematic review

    Science.gov (United States)

    Hopperton, K E; Mohammad, D; Trépanier, M O; Giuliano, V; Bazinet, R P

    2018-01-01

    Neuroinflammation is proposed as one of the mechanisms by which Alzheimer’s disease pathology, including amyloid-β plaques, leads to neuronal death and dysfunction. Increases in the expression of markers of microglia, the main neuroinmmune cell, are widely reported in brains from patients with Alzheimer’s disease, but the literature has not yet been systematically reviewed to determine whether this is a consistent pathological feature. A systematic search was conducted in Medline, Embase and PsychINFO for articles published up to 23 February 2017. Papers were included if they quantitatively compared microglia markers in post-mortem brain samples from patients with Alzheimer’s disease and aged controls without neurological disease. A total of 113 relevant articles were identified. Consistent increases in markers related to activation, such as major histocompatibility complex II (36/43 studies) and cluster of differentiation 68 (17/21 studies), were identified relative to nonneurological aged controls, whereas other common markers that stain both resting and activated microglia, such as ionized calcium-binding adaptor molecule 1 (10/20 studies) and cluster of differentiation 11b (2/5 studies), were not consistently elevated. Studies of ionized calcium-binding adaptor molecule 1 that used cell counts almost uniformly identified no difference relative to control, indicating that increases in activation occurred without an expansion of the total number of microglia. White matter and cerebellum appeared to be more resistant to these increases than other brain regions. Nine studies were identified that included high pathology controls, patients who remained free of dementia despite Alzheimer’s disease pathology. The majority (5/9) of these studies reported higher levels of microglial markers in Alzheimer’s disease relative to controls, suggesting that these increases are not solely a consequence of Alzheimer’s disease pathology. These results show that

  10. Microglia Dictate the Impact of Saturated Fat Consumption on Hypothalamic Inflammation and Neuronal Function

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    Martin Valdearcos

    2014-12-01

    Full Text Available Diets rich in saturated fat produce inflammation, gliosis, and neuronal stress in the mediobasal hypothalamus (MBH. Here, we show that microglia mediate this process and its functional impact. Although microglia and astrocytes accumulate in the MBH of mice fed a diet rich in saturated fatty acids (SFAs, only the microglia undergo inflammatory activation, along with a buildup of hypothalamic SFAs. Enteric gavage specifically with SFAs reproduces microglial activation and neuronal stress in the MBH, and SFA treatment activates murine microglia, but not astrocytes, in culture. Moreover, depleting microglia abrogates SFA-induced inflammation in hypothalamic slices. Remarkably, depleting microglia from the MBH of mice abolishes inflammation and neuronal stress induced by excess SFA consumption, and in this context, microglial depletion enhances leptin signaling and reduces food intake. We thus show that microglia sense SFAs and orchestrate an inflammatory process in the MBH that alters neuronal function when SFA consumption is high.

  11. Regulation of microglia activity by glaucocalyxin-A: attenuation of lipopolysaccharide-stimulated neuroinflammation through NF-κB and p38 MAPK signaling pathways.

    Directory of Open Access Journals (Sweden)

    Byung-Wook Kim

    Full Text Available Microglial cells are the resident macrophages and intrinsic arm of the central nervous system innate immune defense. Microglial cells become activated in response to injury, infection, environmental toxins, and other stimuli that threaten neuronal survival. Therefore, regulating microglial activation may have therapeutic benefits that lead to alleviating the progression of inflammatory-mediated neurodegeneration. In the present study, we investigated the effect of glaucocalyxin A (GLA isolated from Rabdosia japonica on the production of pro-inflammatory mediators in lipopolysaccharide (LPS-stimulated primary microglia and BV-2 cells. GLA significantly inhibited LPS-induced production of nitric oxide and reversed the morphological changes in primary microglia. Further, GLA suppressed expression of inducible nitric oxide synthase and cyclooxygenase-2 dose-dependently at the mRNA and protein levels. The production of proinflammatory cytokines such as tumor necrosis factor-α, interleukin-1β (IL-1β, and IL-6 were inhibited by suppressing their transcriptional activity. Furthermore, GLA suppressed nuclear factor-κB activation by blocking degradation of IκB-α and inhibited the induction of lipocalin-2 expression in LPS-stimulated BV-2 cells. Mechanistic study revealed that the inhibitory effects of GLA were accompanied by blocking the p38 mitogen activated protein kinase signaling pathway in activated microglia. In conclusion, given that microglial activation contributes to the pathogenesis of neurodegenerative diseases, GLA could be developed as a potential therapeutic agent for treating microglia-mediated neuroinflammatory diseases.

  12. Costunolide inhibits proinflammatory cytokines and iNOS in activated murine BV2 microglia.

    Science.gov (United States)

    Rayan, Nirmala Arul; Baby, Nimmi; Pitchai, Daisy; Indraswari, Fransisca; Ling, Eng-Ang; Lu, Jia; Dheen, Thameem

    2011-06-01

    Costunolide, a sesquiterpene lactone present in Costus speciosus root exerts a variety of pharmacological activity but its effects on neuroinflammation have not been studied. Microglia, the resident phagocytic cells in the central nervous system respond to neuroinflammation and their overwhelming response in turn aggravate brain damage during infection, ischemia and neurodegenerative diseases. In this study, we report the effect of Costunolide on the production of proinflammatory mediators and mechanisms involved in BV2 microglial cells stimulated with LPS. Costunolide attenuated the expression of tumour necrosis factor-alpha, interleukin-1,6, inducible nitric oxide synthase, monocyte chemotactic protein 1 and cyclooxygenase 2 in activated microglia. This Costunolide-mediated inhibition was correspondent with the inhibition of NFkappaB activation. It has been further shown that Costunolide suppressed MAPK pathway activation by inducing MKP-1 production. Collectively our results suggest that Costunolide shows an ability to inhibit expression of multiple neuroinflammatory mediators and this is attributable to the compounds inhibition of NFkappaB and MAPK activation. This novel role of Costunolide upon investigation may aid in developing better therapeutic strategies for treatment of neuroinflammatory diseases.

  13. The Role of the Innate Immune System in Alzheimer’s Disease and Frontotemporal Lobar Degeneration: An Eye on Microglia

    Directory of Open Access Journals (Sweden)

    Elisa Ridolfi

    2013-01-01

    Full Text Available In the last few years, genetic and biomolecular mechanisms at the basis of Alzheimer’s disease (AD and frontotemporal lobar degeneration (FTLD have been unraveled. A key role is played by microglia, which represent the immune effector cells in the central nervous system (CNS. They are extremely sensitive to the environmental changes in the brain and are activated in response to several pathologic events within the CNS, including altered neuronal function, infection, injury, and inflammation. While short-term microglial activity has generally a neuroprotective role, chronic activation has been implicated in the pathogenesis of neurodegenerative disorders, including AD and FTLD. In this framework, the purpose of this review is to give an overview of clinical features, genetics, and novel discoveries on biomolecular pathogenic mechanisms at the basis of these two neurodegenerative diseases and to outline current evidence regarding the role played by activated microglia in their pathogenesis.

  14. The role of the innate immune system in Alzheimer's disease and frontotemporal lobar degeneration: an eye on microglia.

    Science.gov (United States)

    Ridolfi, Elisa; Barone, Cinzia; Scarpini, Elio; Galimberti, Daniela

    2013-01-01

    In the last few years, genetic and biomolecular mechanisms at the basis of Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD) have been unraveled. A key role is played by microglia, which represent the immune effector cells in the central nervous system (CNS). They are extremely sensitive to the environmental changes in the brain and are activated in response to several pathologic events within the CNS, including altered neuronal function, infection, injury, and inflammation. While short-term microglial activity has generally a neuroprotective role, chronic activation has been implicated in the pathogenesis of neurodegenerative disorders, including AD and FTLD. In this framework, the purpose of this review is to give an overview of clinical features, genetics, and novel discoveries on biomolecular pathogenic mechanisms at the basis of these two neurodegenerative diseases and to outline current evidence regarding the role played by activated microglia in their pathogenesis.

  15. Selective enhancement of wnt4 expression by cyclic AMP-associated cooperation between rat central astrocytes and microglia

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    Ohnishi, Masatoshi, E-mail: ohnishi@fupharm.fukuyama-u.ac.jp [Department of Pharmacotherapeutics, Graduate School of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Department of Pharmacotherapeutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Urasaki, Tomoka [Department of Pharmacotherapeutics, Graduate School of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Ochiai, Hiroyuki; Matsuoka, Kohei; Takeo, Shin; Harada, Tomoki; Ohsugi, Yoshihito [Department of Pharmacotherapeutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Inoue, Atsuko [Department of Pharmacotherapeutics, Graduate School of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Department of Pharmacotherapeutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan)

    2015-11-13

    The wnt protein family has important members involved in cell differentiation, proliferation and plasticity expression; however, little is known about its biosynthesis processes. On the other hand, an increase in the intracerebral cyclic adenosine 3′, 5’-monophosphate (cAMP) level leads to synaptic plasticity via the de novo synthesis of any protein. Here, the effect of dibutyryl cAMP (dbcAMP), a membrane permeability cAMP analog, on the wnt family was investigated in rat primary-cultured glial cells containing astrocytes and microglia. Among wnt3a, 4, 5a, 7a and 11 mRNA, only wnt4 expression was increased by longer treatment (24 h), compared with short treatment (2 h), with dbcAMP in a concentration-dependent manner, and its effect reached statistical significance at 1 mM. In cultures of isolated astrocytes or microglia, wnt4 expression was not affected by 1 mM dbcAMP for 24 h, and microglial wnt4 protein was undetectable even when cells were treated with the drug. Mixed glial cells treated for 24 h with 1 mM dbcAMP showed significantly increased wnt4 protein, as well as mRNA. Immunofluorescence manifested that cells that expressed wnt4 protein were astrocytes, but not microglia. Intraperitoneal injection of 1.25 mg/kg rolipram, a phosphodiesterase (PDE) IV inhibitor that can pass through the blood brain barrier and inhibits cAMP degradation specifically, showed a tendency to increase wnt4 expression in the adult rat brain after 24 h, and the increases in wnt4 mRNA and protein levels reached statistical significance in the hippocampus and striatum, respectively. This is the first finding to help elucidate the selective biosynthesis of central wnt4 through cAMP-stimulated microglia and astrocytes interaction. - Highlights: • Dibutyryl cAMP increased wnt4, but not wnt3a, 5a, 7a and 11, mRNA in mixed glia. • Wnt4 protein increased in astrocytes co-cultivated with microglia. • It took a long time to robustly increase wnt4 expression. • Rolipram

  16. Selective enhancement of wnt4 expression by cyclic AMP-associated cooperation between rat central astrocytes and microglia

    International Nuclear Information System (INIS)

    Ohnishi, Masatoshi; Urasaki, Tomoka; Ochiai, Hiroyuki; Matsuoka, Kohei; Takeo, Shin; Harada, Tomoki; Ohsugi, Yoshihito; Inoue, Atsuko

    2015-01-01

    The wnt protein family has important members involved in cell differentiation, proliferation and plasticity expression; however, little is known about its biosynthesis processes. On the other hand, an increase in the intracerebral cyclic adenosine 3′, 5’-monophosphate (cAMP) level leads to synaptic plasticity via the de novo synthesis of any protein. Here, the effect of dibutyryl cAMP (dbcAMP), a membrane permeability cAMP analog, on the wnt family was investigated in rat primary-cultured glial cells containing astrocytes and microglia. Among wnt3a, 4, 5a, 7a and 11 mRNA, only wnt4 expression was increased by longer treatment (24 h), compared with short treatment (2 h), with dbcAMP in a concentration-dependent manner, and its effect reached statistical significance at 1 mM. In cultures of isolated astrocytes or microglia, wnt4 expression was not affected by 1 mM dbcAMP for 24 h, and microglial wnt4 protein was undetectable even when cells were treated with the drug. Mixed glial cells treated for 24 h with 1 mM dbcAMP showed significantly increased wnt4 protein, as well as mRNA. Immunofluorescence manifested that cells that expressed wnt4 protein were astrocytes, but not microglia. Intraperitoneal injection of 1.25 mg/kg rolipram, a phosphodiesterase (PDE) IV inhibitor that can pass through the blood brain barrier and inhibits cAMP degradation specifically, showed a tendency to increase wnt4 expression in the adult rat brain after 24 h, and the increases in wnt4 mRNA and protein levels reached statistical significance in the hippocampus and striatum, respectively. This is the first finding to help elucidate the selective biosynthesis of central wnt4 through cAMP-stimulated microglia and astrocytes interaction. - Highlights: • Dibutyryl cAMP increased wnt4, but not wnt3a, 5a, 7a and 11, mRNA in mixed glia. • Wnt4 protein increased in astrocytes co-cultivated with microglia. • It took a long time to robustly increase wnt4 expression. • Rolipram

  17. Agonists for G-protein-coupled receptor 84 (GPR84) alter cellular morphology and motility but do not induce pro-inflammatory responses in microglia.

    Science.gov (United States)

    Wei, Li; Tokizane, Kyohei; Konishi, Hiroyuki; Yu, Hua-Rong; Kiyama, Hiroshi

    2017-10-03

    Several G-protein-coupled receptors (GPCRs) have been shown to be important signaling mediators between neurons and glia. In our previous screening for identification of nerve injury-associated GPCRs, G-protein-coupled receptor 84 (GPR84) mRNA showed the highest up-regulation by microglia after nerve injury. GPR84 is a pro-inflammatory receptor of macrophages in a neuropathic pain mouse model, yet its function in resident microglia in the central nervous system is poorly understood. We used endogenous, natural, and surrogate agonists for GPR84 (capric acid, embelin, and 6-OAU, respectively) and examined their effect on mouse primary cultured microglia in vitro. 6-n-Octylaminouracil (6-OAU), embelin, and capric acid rapidly induced membrane ruffling and motility in cultured microglia obtained from C57BL/6 mice, although these agonists failed to promote microglial pro-inflammatory cytokine expression. Concomitantly, 6-OAU suppressed forskolin-induced increase of cAMP in cultured microglia. Pertussis toxin, an inhibitor of Gi-coupled signaling, completely suppressed 6-OAU-induced microglial membrane ruffling and motility. In contrast, no 6-OAU-induced microglial membrane ruffling and motility was observed in microglia from DBA/2 mice, a mouse strain that does not express functional GPR84 protein due to endogenous nonsense mutation of the GPR84 gene. GPR84 mediated signaling causes microglial motility and membrane ruffling but does not promote pro-inflammatory responses. As GPR84 is a known receptor for medium-chain fatty acids, those released from damaged brain cells may be involved in the enhancement of microglial motility through GPR84 after neuronal injury.

  18. Expression and contributions of the Kir2.1 inward-rectifier K+ channel to proliferation, migration and chemotaxis of microglia in unstimulated and anti-inflammatory states

    Directory of Open Access Journals (Sweden)

    Doris eLam

    2015-05-01

    Full Text Available When microglia respond to CNS damage, they can range from pro-inflammatory (classical, M1 to anti-inflammatory, alternative (M2 and acquired deactivation states. It is important to determine how microglial functions are affected by these activation states, and to identify molecules that regulate their behavior. Microglial proliferation and migration are crucial during development and following damage in the adult, and both functions are Ca2+-dependent. In many cell types, the membrane potential and driving force for Ca2+ influx are regulated by inward-rectifier K+ channels, including Kir2.1, which is prevalent in microglia. However, it is not known whether Kir2.1 expression and contributions are altered in anti-inflammatory states. We tested the hypothesis that Kir2.1 contributes to Ca2+ entry, proliferation and migration of rat microglia. Kir2.1 (KCNJ2 transcript expression, current amplitude, and proliferation were comparable in unstimulated microglia and following alternative activation (IL-4 stimulated and acquired deactivation (IL-10 stimulated. To examine functional roles of Kir2.1 in microglia, we first determined that ML133 was more effective than the commonly used blocker, Ba2+; i.e., ML133 was potent (IC50=3.5 M and voltage independent. Both blockers slightly increased proliferation in unstimulated or IL-4 (but not IL-10-stimulated microglia. Stimulation with IL-4 or IL-10 increased migration and ATP-induced chemotaxis, and blocking Kir2.1 greatly reduced both but ML133 was more effective. In all three activation states, blocking Kir2.1 with ML133 dramatically reduced Ca2+ influx through Ca2+-release-activated Ca2+ (CRAC channels. Thus, Kir2.1 channel activity is necessary for microglial Ca2+ signaling and migration under resting and anti-inflammatory states but the channel weakly inhibits proliferation.

  19. Interaction of inflammatory and anti-inflammatory responses in microglia by Staphylococcus aureus-derived lipoteichoic acid

    International Nuclear Information System (INIS)

    Huang, Bor-Ren; Tsai, Cheng-Fang; Lin, Hsiao-Yun; Tseng, Wen-Pei; Huang, Shiang-Suo; Wu, Chi-Rei; Lin, Chingju; Yeh, Wei-Lan; Lu, Dah-Yuu

    2013-01-01

    We investigated the interaction between proinflammatory and inflammatory responses caused by Staphylococcus aureus-derived lipoteichoic acid (LTA) in primary cultured microglial cells and BV-2 microglia. LTA induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein levels increase in a concentration- and time-dependent manner. Meanwhile, LTA also increased nitric oxide (NO) and PGE 2 production in microglia. Administration of TLR2 antagonist effectively inhibited LTA-induced NO, iNOS, and COX-2 expression. Moreover, treatment of cells with LTA caused a time-dependent activation of ERK, p38, JNK, as well as AKT. We also found that LTA-induced iNOS and COX-2 up-regulation were attenuated by p38, JNK, and PI3-kinase inhibitors. On the other hand, LTA-enhanced HO-1 expression was attenuated by p38 and PI3-kinase inhibitors. Treatment of cells with NF-κB and AP-1 inhibitors antagonized LTA-induced iNOS and COX-2 expression. However, only NF-κB inhibitors reduced LTA-induced HO-1 expression in microglia. Furthermore, stimulation of cells with LTA also activated IκBα phosphorylation, p65 phosphorylation at Ser 536 , and c-Jun phosphorylation. Moreover, LTA-induced increases of κB-DNA and AP-1-DNA binding activity were inhibited by p38, JNK, and PI3-kinase inhibitors. HO-1 activator CoPP IX dramatically reversed LTA-induced iNOS expression. Our results provided mechanisms linking LTA and inflammation/anti-inflammation, and indicated that LTA plays a regulatory role in microglia activation. - Highlights: • LTA causes an increase in iNOS, COX-2, and HO-1 expression in microglia. • LTA induces iNOS and COX-2 expression through TLR-2/NF-κB and AP-1 pathways. • HO-1 expression is regulated through p38, JNK, PI3K/AKT and AP-1 pathways. • Induced HO-1 reduces LTA-induced iNOS expression. • LTA plays a regulatory role on inflammatory/anti-inflammatory responses

  20. Interaction of inflammatory and anti-inflammatory responses in microglia by Staphylococcus aureus-derived lipoteichoic acid

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    Huang, Bor-Ren [Department of Neurosurgery, Buddhist Tzu Chi General Hospital, Taichung Branch, Taichung, Taiwan (China); Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan (China); Tsai, Cheng-Fang [Department of Biotechnology, Asia University, Taichung, Taiwan (China); Lin, Hsiao-Yun [Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan (China); Tseng, Wen-Pei [Graduate Institute of Sports and Health, National Changhua University of Education, Changhua County, Taiwan (China); Huang, Shiang-Suo [Department of Pharmacology and Institute of Medicine, College of Medicine, Chung Shan Medical University, Taiwan (China); Wu, Chi-Rei [Graduate Institute of Chinese Pharmaceutical Sciences, College of Pharmacy, China Medical University, Taiwan (China); Lin, Chingju [Department of Physiology, School of Medicine, China Medical University, Taichung, Taiwan (China); Yeh, Wei-Lan [Cancer Research Center, Department of Medical Research, Changhua Christian Hospital, Changhua, Taiwan (China); Lu, Dah-Yuu, E-mail: dahyuu@mail.cmu.edu.tw [Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan (China)

    2013-05-15

    We investigated the interaction between proinflammatory and inflammatory responses caused by Staphylococcus aureus-derived lipoteichoic acid (LTA) in primary cultured microglial cells and BV-2 microglia. LTA induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein levels increase in a concentration- and time-dependent manner. Meanwhile, LTA also increased nitric oxide (NO) and PGE{sub 2} production in microglia. Administration of TLR2 antagonist effectively inhibited LTA-induced NO, iNOS, and COX-2 expression. Moreover, treatment of cells with LTA caused a time-dependent activation of ERK, p38, JNK, as well as AKT. We also found that LTA-induced iNOS and COX-2 up-regulation were attenuated by p38, JNK, and PI3-kinase inhibitors. On the other hand, LTA-enhanced HO-1 expression was attenuated by p38 and PI3-kinase inhibitors. Treatment of cells with NF-κB and AP-1 inhibitors antagonized LTA-induced iNOS and COX-2 expression. However, only NF-κB inhibitors reduced LTA-induced HO-1 expression in microglia. Furthermore, stimulation of cells with LTA also activated IκBα phosphorylation, p65 phosphorylation at Ser{sup 536}, and c-Jun phosphorylation. Moreover, LTA-induced increases of κB-DNA and AP-1-DNA binding activity were inhibited by p38, JNK, and PI3-kinase inhibitors. HO-1 activator CoPP IX dramatically reversed LTA-induced iNOS expression. Our results provided mechanisms linking LTA and inflammation/anti-inflammation, and indicated that LTA plays a regulatory role in microglia activation. - Highlights: • LTA causes an increase in iNOS, COX-2, and HO-1 expression in microglia. • LTA induces iNOS and COX-2 expression through TLR-2/NF-κB and AP-1 pathways. • HO-1 expression is regulated through p38, JNK, PI3K/AKT and AP-1 pathways. • Induced HO-1 reduces LTA-induced iNOS expression. • LTA plays a regulatory role on inflammatory/anti-inflammatory responses.

  1. G protein-coupled receptor 84, a microglia-associated protein expressed in neuroinflammatory conditions.

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    Bouchard, Caroline; Pagé, Julie; Bédard, Andréanne; Tremblay, Pierrot; Vallières, Luc

    2007-06-01

    G protein-coupled receptor 84 (GPR84) is a recently discovered member of the seven transmembrane receptor superfamily whose function and regulation are unknown. Here, we report that in mice suffering from endotoxemia, microglia express GPR84 in a strong and sustained manner. This property is shared by subpopulations of peripheral macrophages and, to a much lesser extent, monocytes. The induction of GPR84 expression by endotoxin is mediated, at least in part, by proinflammatory cytokines, notably tumor necrosis factor (TNF) and interleukin-1 (IL-1), because mice lacking either one or both of these molecules have fewer GPR84-expressing cells in their cerebral cortex than wild-type mice during the early phase of endotoxemia. Moreover, when injected intracerebrally or added to microglial cultures, recombinant TNF stimulates GPR84 expression through a dexamethasone-insensitive mechanism. Finally, we show that microglia produce GPR84 not only during endotoxemia, but also during experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. In conclusion, this study reports the identification of a new sensitive marker of microglial activation, which may play an important regulatory role in neuroimmunological processes, acting downstream to the effects of proinflammatory mediators.

  2. Visfatin Triggers Anorexia and Body Weight Loss through Regulating the Inflammatory Response in the Hypothalamic Microglia

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    Thai Hien Tu

    2017-01-01

    Full Text Available Visfatin is an adipokine that is secreted from adipose tissue, and it is involved in a variety of physiological processes. In particular, visfatin has been implicated in metabolic diseases, such as obesity and type 2 diabetes, which are directly linked to systemic inflammation. However, the potential impacts of visfatin on the hypothalamic control of energy homeostasis, which is involved in microglial inflammation, have not fully been investigated. In this study, we found that treatment with exogenous recombinant visfatin protein led to the activation of the inflammatory response in a microglial cell line. In addition, we observed that central administration of visfatin led to the activation of microglia in the hypothalamus. Finally, we found that visfatin reduced food intake and body weight through activating POMC neurons in association with microglia activation in mice. These findings indicate that elevation of central visfatin levels may be associated with homeostatic feeding behavior in response to metabolic shifts, such as increased adiposity following inflammatory processes in the hypothalamus.

  3. Surface functionality affects the biodistribution and microglia-targeting of intra-amniotically delivered dendrimers.

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    Zhang, Fan; Nance, Elizabeth; Zhang, Zhi; Jasty, Venkatasai; Kambhampati, Siva P; Mishra, Manoj K; Burd, Irina; Romero, Roberto; Kannan, Sujatha; Kannan, Rangaramanujam M

    2016-09-10

    Cerebral Palsy (CP) is a chronic childhood disorder with limited therapeutic options. Maternal intrauterine inflammation/infection is a major risk factor in the pathogenesis of CP. In pre-clinical models, dendrimer-based therapies are viable in postnatal period, attenuating inflammation and improving motor function in vivo. However, treatment to the mother, in the prenatal period, may provide the possibility of preventing/resolving inflammation at early stages. Towards this goal, we used a maternal intrauterine inflammation-induced rabbit model of CP to study fetal-maternal transport and neuroinflammation targeting of intra-amniotically administrated dendrimers with neutral/anionic surface functionality. Our study suggested both hydroxyl-terminated 'neutral' (D-OH) and carboxyl-terminated 'anionic' (D-COOH) Polyamidoamine (PAMAM) dendrimers were absorbed by fetuses and demonstrated bi-directional transport between fetuses and mother. D-OH was more effective in crossing the fetal blood-brain barrier, and targeting activated microglia. The cell-specific targeting was associated with the extent of microglia activation. This study demonstrated intra-amniotically administered hydroxyl PAMAM dendrimers could be an effective drug delivery vehicle for targeting fetal inflammation and preventing subsequent neurologic injury associated with chorioamnionitis. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Surface functionality affects the biodistribution and microglia-targeting of intra-amniotically delivered dendrimers☆

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    Zhang, Fan; Nance, Elizabeth; Zhang, Zhi; Jasty, Venkatasai; Kambhampati, Siva P.; Mishra, Manoj K.; Burd, Irina; Romero, Roberto; Kannan, Sujatha; Kannan, Rangaramanujam M.

    2017-01-01

    Cerebral Palsy (CP) is a chronic childhood disorder with limited therapeutic options. Maternal intrauterine inflammation/infection is a major risk factor in the pathogenesis of CP. In pre-clinical models, dendrimer-based therapies are viable in postnatal period, attenuating inflammation and improving motor function in vivo. However, treatment to the mother, in the prenatal period, may provide the possibility of preventing/resolving inflammation at early stages. Towards this goal, we used a maternal intrauterine inflammation-induced rabbit model of CP to study fetal-maternal transport and neuroinflammation targeting of intra-amniotically administrated dendrimers with neutral/anionic surface functionality. Our study suggested both hydroxyl-terminated ‘neutral’ (D-OH) and carboxyl-terminated ‘anionic’ (D-COOH) Polyamidoamine (PAMAM) dendrimers were absorbed by fetuses and demonstrated bi-directional transport between fetuses and mother. D-OH was more effective in crossing the fetal blood-brain barrier, and targeting activated microglia. The cell-specific targeting was associated with the extent of microglia activation. This study demonstrated intra-amniotically administered hydroxyl PAMAM dendrimers could be an effective drug delivery vehicle for targeting fetal inflammation and preventing subsequent neurologic injury associated with chorioamnionitis. PMID:27378700

  5. Lithium limits trimethyltin-induced cytotoxicity and proinflammatory response in microglia without affecting the concurrent autophagy impairment.

    Science.gov (United States)

    Fabrizi, Cinzia; Pompili, Elena; Somma, Francesca; De Vito, Stefania; Ciraci, Viviana; Artico, Marco; Lenzi, Paola; Fornai, Francesco; Fumagalli, Lorenzo

    2017-02-01

    Trimethyltin (TMT) is a highly toxic molecule present as an environmental contaminant causing neurodegeneration particularly of the limbic system both in humans and in rodents. We recently described the occurrence of impairment in the late stages of autophagy in TMT-intoxicated astrocytes. Here we show that similarly to astrocytes also in microglia, TMT induces the precocious block of autophagy indicated by the accumulation of the autophagosome marker, microtubule associated protein light chain 3. Consistent with autophagy impairment we observe in TMT-treated microglia the accumulation of p62/SQSTM1, a protein specifically degraded through this pathway. Lithium has been proved effective in limiting neurodegenerations and, in particular, in ameliorating symptoms of TMT intoxication in rodents. In our in vitro model, lithium displays a pro-survival and anti-inflammatory action reducing both cell death and the proinflammatory response of TMT-treated microglia. In particular, lithium exerts these activities without reducing TMT-induced accumulation of light chain 3 protein. In fact, the autophagic block imposed by TMT is unaffected by lithium administration. These results are of interest as defects in the execution of autophagy are frequently observed in neurodegenerative diseases and lithium is considered a promising therapeutic agent for these pathologies. Thus, it is relevant that this cation can still maintain its pro-survival and anti-inflammatory role in conditions of autophagy block. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Immune dysregulation and cognitive vulnerability in the aging brain: Interactions of microglia, IL-1β, BDNF and synaptic plasticity.

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    Patterson, Susan L

    2015-09-01

    Older individuals often experience declines in cognitive function after events (e.g. infection, or injury) that trigger activation of the immune system. This occurs at least in part because aging sensitizes the response of microglia (the brain's resident immune cells) to signals triggered by an immune challenge. In the aging brain, microglia respond to these signals by producing more pro-inflammatory cytokines (e.g. interleukin-1beta or IL-1β) and producing them for longer than microglia in younger brains. This exaggerated inflammatory response can compromise processes critical for optimal cognitive functioning. Interleukin-1β is central to the inflammatory response and is a key mediator and modulator of an array of associated biological functions; thus its production and release is usually very tightly regulated. This review will focus on the impact of dysregulated production of IL-1β on hippocampus dependent-memory systems and associated synaptic plasticity processes. The neurotrophin brain-derived neurotrophic factor (BNDF) helps to protect neurons from damage caused by infection or injury, and it plays a critical role in many of the same memory and hippocampal plasticity processes compromised by dysregulated production of IL-1β. This suggests that an exaggerated brain inflammatory response, arising from aging and a secondary immune challenge, may erode the capacity to provide the BDNF needed for memory-related plasticity processes at hippocampal synapses. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Effect of the semen extract of Cuscuta chinensis on inflammatory responses in LPS-stimulated BV-2 microglia.

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    Kang, Seok Yong; Jung, Hyo Won; Lee, Mi-Young; Lee, Hye Won; Chae, Seong Wook; Park, Yong-Ki

    2014-08-01

    To investigate the anti-inflammatory activities of the semen extract of Cuscuta chinensis Lam. (Cuscutae Semen; CS) on the production of inflammatory mediators, nitric oxide (NO), prostaglandin 2 (PGE2), and proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated BV-2 microglia. BV-2 cells were treated with CS extract for 30 min, and then stimulated with LPS or without for 24 h. The levels of NO, PGE2 and proinflammatory cytokines were measured by Griess assay and ELISA. The expression of inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 mRNA and protein was determined by RT-PCR and Western blot, respectively. The phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK), and the nuclear expression of nuclear factor (NF)-κB p65 were investigated by Western blot analysis. CS extract significantly decreased the production of NO and PGE2 by suppressing the expression of iNOS and COX-2 in activated microglia. CS extract decreased the production of TNF-α, IL-1β, and IL-6 by down-regulating their transcription levels. In addition, CS extract suppressed the phosphorylation of ERK1/2, JNK, and p38 MAPK, and the nuclear translocation of NF-κB p65 in activated microglia. These results indicate that CS extract is capable of suppressing the inflammatory response by microglia activation, suggesting that CS extract has potential in the treatment of brain inflammation. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  8. Two faces of chondroitin sulfate proteoglycan in spinal cord repair: a role in microglia/macrophage activation.

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    Asya Rolls

    2008-08-01

    Full Text Available BACKGROUND: Chondroitin sulfate proteoglycan (CSPG is a major component of the glial scar. It is considered to be a major obstacle for central nervous system (CNS recovery after injury, especially in light of its well-known activity in limiting axonal growth. Therefore, its degradation has become a key therapeutic goal in the field of CNS regeneration. Yet, the abundant de novo synthesis of CSPG in response to CNS injury is puzzling. This apparent dichotomy led us to hypothesize that CSPG plays a beneficial role in the repair process, which might have been previously overlooked because of nonoptimal regulation of its levels. This hypothesis is tested in the present study. METHODS AND FINDINGS: We inflicted spinal cord injury in adult mice and examined the effects of CSPG on the recovery process. We used xyloside to inhibit CSPG formation at different time points after the injury and analyzed the phenotype acquired by the microglia/macrophages in the lesion site. To distinguish between the resident microglia and infiltrating monocytes, we used chimeric mice whose bone marrow-derived myeloid cells expressed GFP. We found that CSPG plays a key role during the acute recovery stage after spinal cord injury in mice. Inhibition of CSPG synthesis immediately after injury impaired functional motor recovery and increased tissue loss. Using the chimeric mice we found that the immediate inhibition of CSPG production caused a dramatic effect on the spatial organization of the infiltrating myeloid cells around the lesion site, decreased insulin-like growth factor 1 (IGF-1 production by microglia/macrophages, and increased tumor necrosis factor alpha (TNF-alpha levels. In contrast, delayed inhibition, allowing CSPG synthesis during the first 2 d following injury, with subsequent inhibition, improved recovery. Using in vitro studies, we showed that CSPG directly activated microglia/macrophages via the CD44 receptor and modulated neurotrophic factor secretion by

  9. Receptor-heteromer mediated regulation of endocannabinoid signaling in activated microglia. Role of CB1 and CB2 receptors and relevance for Alzheimer's disease and levodopa-induced dyskinesia.

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    Navarro, Gemma; Borroto-Escuela, Dasiel; Angelats, Edgar; Etayo, Íñigo; Reyes-Resina, Irene; Pulido-Salgado, Marta; Rodríguez-Pérez, Ana I; Canela, Enric I; Saura, Josep; Lanciego, José Luis; Labandeira-García, José Luis; Saura, Carlos A; Fuxe, Kjell; Franco, Rafael

    2018-01-01

    Endocannabinoids are important regulators of neurotransmission and, acting on activated microglia, they are postulated as neuroprotective agents. Endocannabinoid action is mediated by CB 1 and CB 2 receptors, which may form heteromeric complexes (CB 1 -CB 2 Hets) with unknown function in microglia. We aimed at establishing the expression and signaling properties of cannabinoid receptors in resting and LPS/IFN-γ-activated microglia. In activated microglia mRNA transcripts increased (2 fold for CB 1 and circa 20 fold for CB 2 ), whereas receptor levels were similar for CB 1 and markedly upregulated for CB 2 ; CB 1 -CB 2 Hets were also upregulated. Unlike in resting cells, CB 2 receptors became robustly coupled to G i in activated cells, in which CB 1 -CB 2 Hets mediated a potentiation effect. Hence, resting cells were refractory while activated cells were highly responsive to cannabinoids. Interestingly, similar results were obtained in cultures treated with ß-amyloid (Aß 1-42 ). Microglial activation markers were detected in the striatum of a Parkinson's disease (PD) model and, remarkably, in primary microglia cultures from the hippocampus of mutant β-amyloid precursor protein (APP Sw,Ind ) mice, a transgenic Alzheimer's disease (AD) model. Also of note was the similar cannabinoid receptor signaling found in primary cultures of microglia from APP Sw,Ind and in cells from control animals activated using LPS plus IFN-γ. Expression of CB 1 -CB 2 Hets was increased in the striatum from rats rendered dyskinetic by chronic levodopa treatment. In summary, our results showed sensitivity of activated microglial cells to cannabinoids, increased CB 1 -CB 2 Het expression in activated microglia and in microglia from the hippocampus of an AD model, and a correlation between levodopa-induced dyskinesia and striatal microglial activation in a PD model. Cannabinoid receptors and the CB 1 -CB 2 heteroreceptor complex in activated microglia have potential as targets in the

  10. The endogenous hallucinogen and trace amine N,N-dimethyltryptamine (DMT displays potent protective effects against hypoxia via sigma-1 receptor activation in human primary iPSC-derived cortical neurons and microglia-like immune cells

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    Attila Szabo

    2016-09-01

    Full Text Available N,N-dimethyltryptamine (DMT is a potent endogenous hallucinogen present in the brain of humans and other mammals. Despite extensive research, its physiological role remains largely unknown. Recently, DMT has been found to activate the sigma-1 receptor (Sig-1R, an intracellular chaperone fulfilling an interface role between the endoplasmic reticulum (ER and mitochondria. It ensures the correct transmission of ER stress into the nucleus resulting in the enhanced production of antistress and antioxidant proteins. Due to this function, the activation of Sig-1R can mitigate the outcome of hypoxia or oxidative stress. In this paper we aimed to test the hypothesis that DMT plays a neuroprotective role in the brain by activating the Sig-1R. We tested whether DMT can mitigate hypoxic stress in in vitro cultured human cortical neurons (derived from induced pluripotent stem cells, and in monocyte-derived macrophages and dendritic cells. Here we report that DMT robustly increases the survival of these cell types in severe hypoxia (0.5% O2 through the Sig-1R. Furthermore, this phenomenon is associated with the decreased expression and function of the alpha subunit of the hypoxia-inducible factor 1 (HIF-1 suggesting that DMT-mediated Sig-1R activation may alleviate hypoxia-induced cellular stress and increase survival in a HIF-1-independent manner. Our results reveal a novel and important role of DMT in human cellular physiology. We postulate that this compound may be endogenously generated in situations of stress, ameliorating the adverse effects of hypoxic/ischemic insult to the brain.

  11. The Endogenous Hallucinogen and Trace Amine N,N-Dimethyltryptamine (DMT) Displays Potent Protective Effects against Hypoxia via Sigma-1 Receptor Activation in Human Primary iPSC-Derived Cortical Neurons and Microglia-Like Immune Cells.

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    Szabo, Attila; Kovacs, Attila; Riba, Jordi; Djurovic, Srdjan; Rajnavolgyi, Eva; Frecska, Ede

    2016-01-01

    N,N-dimethyltryptamine (DMT) is a potent endogenous hallucinogen present in the brain of humans and other mammals. Despite extensive research, its physiological role remains largely unknown. Recently, DMT has been found to activate the sigma-1 receptor (Sig-1R), an intracellular chaperone fulfilling an interface role between the endoplasmic reticulum (ER) and mitochondria. It ensures the correct transmission of ER stress into the nucleus resulting in the enhanced production of antistress and antioxidant proteins. Due to this function, the activation of Sig-1R can mitigate the outcome of hypoxia or oxidative stress. In this paper, we aimed to test the hypothesis that DMT plays a neuroprotective role in the brain by activating the Sig-1R. We tested whether DMT can mitigate hypoxic stress in in vitro cultured human cortical neurons (derived from induced pluripotent stem cells, iPSCs), monocyte-derived macrophages (moMACs), and dendritic cells (moDCs). Results showed that DMT robustly increases the survival of these cell types in severe hypoxia (0.5% O2) through the Sig-1R. Furthermore, this phenomenon is associated with the decreased expression and function of the alpha subunit of the hypoxia-inducible factor 1 (HIF-1) suggesting that DMT-mediated Sig-1R activation may alleviate hypoxia-induced cellular stress and increase survival in a HIF-1-independent manner. Our results reveal a novel and important role of DMT in human cellular physiology. We postulate that this compound may be endogenously generated in situations of stress, ameliorating the adverse effects of hypoxic/ischemic insult to the brain.

  12. Seizure progression and inflammatory mediators promote pericytosis and pericyte-microglia clustering at the cerebrovasculature.

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    Klement, Wendy; Garbelli, Rita; Zub, Emma; Rossini, Laura; Tassi, Laura; Girard, Benoit; Blaquiere, Marine; Bertaso, Federica; Perroy, Julie; de Bock, Frederic; Marchi, Nicola

    2018-05-01

    Cerebrovascular dysfunction and inflammation occur in epilepsy. Here we asked whether pericytes, a pivotal cellular component of brain capillaries, undergo pathological modifications during experimental epileptogenesis and in human epilepsy. We evaluated whether pro-inflammatory cytokines, present in the brain during seizures, contribute to pericyte morphological modifications. In vivo, unilateral intra-hippocampal kainic acid (KA) injections were performed in NG2DsRed/C57BL6 mice to induce status epilepticus (SE), epileptogenesis, and spontaneous recurrent seizures (SRS). NG2DsRed mice were used to visualize pericytes during seizure progression. The effect triggered by recombinant IL-1β, TNFα, or IL-6 on pericytes was evaluated in NG2DsRed hippocampal slices and in human-derived cell culture. Human brain specimens obtained from temporal lobe epilepsy (TLE) with or without sclerosis (HS) and focal cortical dysplasia (FCD-IIb) were evaluated for pericyte-microglial cerebrovascular assembly. A disarray of NG2DsRed + pericyte soma and ramifications was found 72 h post-SE and 1 week post-SE (epileptogenesis) in the hippocampus. Pericyte modifications topographically overlapped with IBA1 + microglia clustering around the capillaries with cases of pericytes lodged within the microglial cells. Microglial clustering around the NG2DsRed pericytes lingered at SRS. Pericyte proliferation (Ki67 + ) occurred 72 h post-SE and during epileptogenesis and returned towards control levels at SRS. Human epileptic brain tissues showed pericyte-microglia assemblies with IBA1/HLA microglial cells outlining the capillary wall in TLE-HS and FCD-IIb specimens. Inflammatory mediators contributed to pericyte modifications, in particular IL-1β elicited pericyte morphological changes and pericyte-microglia clustering in NG2DsRed hippocampal slices. Modifications also occurred when pro-inflammatory cytokines were added to an in vitro culture of pericytes. These results indicate the

  13. Microglia P2Y6 receptor is related to Parkinson’s disease through neuroinflammatory process

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    Xiaodong Yang

    2017-02-01

    Full Text Available Abstract Background Microglia in the central nervous system (CNS were reported to play crucial role in neurodegeneration. Previous studies showed that P2Y6 receptor (P2Y6R mainly contributed to microglia activation and phagocytosis in CNS. However, the level of P2Y6R in Parkinson’s disease (PD patients is unclear. Therefore, we measured the level of P2Y6R in PD patients and speculated whether it could be a potential biomarker for PD. Given on the basis that P2Y6R was higher in PD patients, we further explored the mechanisms underlying P2Y6R in the pathogenesis of PD. Methods We tested the expression level of P2Y6R in the peripheral blood mononuclear cells (PBMCs among 145 PD patients, 170 healthy controls, and 30 multiple system atrophy (MSA patients. We also used a lipopolysaccharide (LPS-stimulated microglial cell culture model to investigate (i the effects of LPS on P2Y6R expression with western blot and RT-PCR, (ii the effects of LPS on UDP expression using HPLC, (iii the effects of UDP/P2Y6R signaling on cytokine expression using western blot, RT-PCR, and ELISA, and (iv the signaling pathways activated by the P2Y6R involved in the neuroinflammation. Results Expression levels of P2Y6R in PD patients were higher than healthy controls and MSA patients. P2Y6R could be a good biomarker of PD. P2Y6R was also upregulated in LPS-treated BV-2 cells and involved in proinflammatory cytokine release through an autocrine loop based on LPS-triggered UDP secretion and accelerated neuroinflammatory responses through the ERK1/2 pathway. Importantly, blocking UDP/P2Y6R signaling could reverse these pathological processes. Conclusions P2Y6R may be a potential clinical biomarker of PD. Blocking P2Y6R may be a potential therapeutic approach to the treatment of PD patients through inhibition of microglia-activated neuroinflammation.

  14. Involvement of Phosphatidylinositol 3-Kinase-Mediated Up-Regulation of IκBα in Anti-Inflammatory Effect of Gemfibrozil in Microglia1

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    Jana, Malabendu; Jana, Arundhati; Liu, Xiaojuan; Ghosh, Sankar; Pahan, Kalipada

    2008-01-01

    The present study underlines the importance of PI3K in mediating the anti-inflammatory effect of gemfibrozil, a prescribed lipid-lowering drug for humans, in mouse microglia. Gemfibrozil inhibited LPS-induced expression of inducible NO synthase (iNOS) and proinflammatory cytokines in mouse BV-2 microglial cells and primary microglia. By overexpressing wild-type and dominant-negative constructs of peroxisome proliferator-activated receptor-α (PPAR-α) in microglial cells and isolating primary microglia from PPAR-α−/− mice, we have demonstrated that gemfibrozil inhibits the activation of microglia independent of PPAR-α. Interestingly, gemfibrozil induced the activation of p85α-associated PI3K (p110β but not p110α) and inhibition of that PI3K by either chemical inhibitors or dominant-negative mutants abrogated the inhibitory effect of gemfibrozil. Conversely, overexpression of the constitutively active mutant of p110 enhanced the inhibitory effect of gemfibrozil on LPS-induced expression of proinflammatory molecules. Similarly, gemfibrozil also inhibited fibrillar amyloid β (Aβ)-, prion peptide (PrP)-, dsRNA (poly IC)-, HIV-1 Tat-, and 1-methyl-4-phenylpyridinium (MPP+)-, but not IFN-γ-, induced microglial expression of iNOS. Inhibition of PI3K also abolished the inhibitory effect of gemfibrozil on Aβ-, PrP-, poly IC-, Tat-, and MPP+-induced microglial expression of iNOS. Involvement of NF-κB activation in LPS-, Aβ-, PrP-, poly IC-, Tat-, and MPP+-, but not IFN-γ-, induced microglial expression of iNOS and stimulation of IκBα expression and inhibition of NF-κB activation by gemfibrozil via the PI3K pathway suggests that gemfibrozil inhibits the activation of NF-κB and the expression of proinflammatory molecules in microglia via PI3K-mediated up-regulation of IκBα. PMID:17785853

  15. Heterotrimeric G protein-dependent WNT-5A signaling to ERK1/2 mediates distinct aspects of microglia proinflammatory transformation

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    Halleskog Carina

    2012-05-01

    Thus, WNT-5A-induced and G protein-dependent signaling to ERK1/2 is important for the regulation of proinflammatory responses in mouse primary microglia cells. We show for the first time that WNT-5A/G protein signaling mediates physiologically important processes in primary mammalian cells with natural receptor and G protein stochiometry. Consequently, WNT-5A emerges as an important means of astrocyte-microglia communication and we, therefore, suggest WNT-5A as a new player in neuroinflammatory conditions, such as neurodegenerative disease, hypoxia, stroke, injury and infection.

  16. CD36 participates in PrP(106-126-induced activation of microglia.

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    Mohammed Kouadir

    Full Text Available Microglial activation is a characteristic feature of the pathogenesis of prion diseases. The molecular mechanisms that underlie prion-induced microglial activation are not very well understood. In the present study, we investigated the role of the class B scavenger receptor CD36 in microglial activation induced by neurotoxic prion protein (PrP fragment 106-126 (PrP(106-126. We first examined the time course of CD36 mRNA expression upon exposure to PrP(106-126 in BV2 microglia. We then analyzed different parameters of microglial activation in PrP(106-126-treated cells in the presence or not of anti-CD36 monoclonal antibody (mAb. The cells were first incubated for 1 h with CD36 monoclonal antibody to block the CD36 receptor, and were then treated with neurotoxic prion peptides PrP(106-126. The results showed that PrP(106-126 treatment led to a rapid yet transitory increase in the mRNA expression of CD36, upregulated mRNA and protein levels of proinflammatory cytokines (IL-1β, IL-6 and TNF-α, increased iNOS expression and nitric oxide (NO production, stimulated the activation of NF-κB and caspase-1, and elevated Fyn activity. The blockade of CD36 had no effect on PrP(106-126-stimulated NF-κB activation and TNF-α protein release, abrogated the PrP(106-126-induced iNOS stimulation, downregulated IL-1β and IL-6 expression at both mRNA and protein levels as well as TNF-α mRNA expression, decreased NO production and Fyn phosphorylation, reduced caspase-1 cleavage induced by moderate PrP(106-126-treatment, but had no effect on caspase-1 activation after treatment with a high concentration of PrP(106-126. Together, these results suggest that CD36 is involved in PrP(106-126-induced microglial activation and that the participation of CD36 in the interaction between PrP(106-126 and microglia may be mediated by Src tyrosine kinases. Our findings provide new insights into the mechanisms underlying the activation of microglia by neurotoxic prion peptides

  17. Long-term impact of systemic bacterial infection on the cerebral vasculature and microglia

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    Püntener Ursula

    2012-06-01

    Full Text Available Abstract Background Systemic infection leads to generation of inflammatory mediators that result in metabolic and behavioural changes. Repeated or chronic systemic inflammation leads to a state of innate immune tolerance: a protective mechanism against overactivity of the immune system. In this study, we investigated the immune adaptation of microglia and brain vascular endothelial cells in response to systemic inflammation or bacterial infection. Methods Mice were given repeated doses of lipopolysaccharide (LPS or a single injection of live Salmonella typhimurium. Inflammatory cytokines were measured in serum, spleen and brain, and microglial phenotype studied by immunohistochemistry. To assess priming of the innate immune response in the brain, mice were infected with Salmonella typhimurium and subsequently challenged with a focal unilateral intracerebral injection of LPS. Results Repeated systemic LPS challenges resulted in increased brain IL-1β, TNF-α and IL-12 levels, despite attenuated systemic cytokine production. Each LPS challenge induced significant changes in burrowing behaviour. In contrast, brain IL-1β and IL-12 levels in Salmonella typhimurium-infected mice increased over three weeks, with high interferon-γ levels in the circulation. Behavioural changes were only observed during the acute phase of the infection. Microglia and cerebral vasculature display an activated phenotype, and focal intracerebral injection of LPS four weeks after infection results in an exaggerated local inflammatory response when compared to non-infected mice. Conclusions These studies reveal that the innate immune cells in the brain do not become tolerant to systemic infection, but are primed instead. This may lead to prolonged and damaging cytokine production that may have a profound effect on the onset and/or progression of pre-existing neurodegenerative disease.

  18. Optimized isolation enables Ex vivo analysis of microglia from various central nervous system regions

    NARCIS (Netherlands)

    De Haas, Alexander H.; Boddeke, Hendricus W. G. M.; Brouwer, Nieske; Biber, Knut

    2007-01-01

    Ex vivo analysis is an accurate and convenient way to study in vivo microglia phenotype and function. However, current microglia isolation protocols for ex vivo analysis show many differences in isolation steps (perfusion, removal of meninges and blood vessels, mechanical dissociation, enzymatic

  19. Microglia Activation, Herpes Infection, and NMDA Receptor Inhibition : Common Pathways to Psychosis?

    NARCIS (Netherlands)

    Klein, Hans C.; Doorduin, Janine; de Witte, Lot; de Vries, Erik; Müller, Norbert; Myint, Aye-Mu; Schwarz, Markus J.

    2015-01-01

    Microglia are the resident macrophages of the brain. Microglia play important housekeeping roles during brain development and during exposure to psychosocial stress, toxins, and infectious pathogens. The hippocampus is a vulnerable brain region in response to these external stressors. In patients

  20. Toll-like receptor activation reveals developmental reorganization and unmasks responder subsets of microglia

    NARCIS (Netherlands)

    Scheffel, Joerg; Regen, Tommy; Van Rossum, Denise; Seifert, Stefanie; Ribes, Sandra; Nau, Roland; Parsa, Roham; Harris, Robert A.; Boddeke, Hendrikus W. G. M.; Chuang, Han-Ning; Pukrop, Tobias; Wessels, Johannes T.; Juergens, Tanja; Merkler, Doron; Brueck, Wolfgang; Schnaars, Mareike; Simons, Mikael; Kettenmann, Helmut; Hanisch, Uwe-Karsten

    2012-01-01

    The sentinel and immune functions of microglia require rapid and appropriate reactions to infection and damage. Their Toll-like receptors (TLRs) sense both as threats. However, whether activated microglia mount uniform responses or whether subsets conduct selective tasks is unknown. We demonstrate

  1. The Interplay between Cyclic AMP, MAPK, and NF-κB Pathways in Response to Proinflammatory Signals in Microglia

    Directory of Open Access Journals (Sweden)

    Mousumi Ghosh

    2015-01-01

    Full Text Available Cyclic AMP is an important intracellular regulator of microglial cell homeostasis and its negative perturbation through proinflammatory signaling results in microglial cell activation. Though cytokines, TNF-α and IL-1β, decrease intracellular cyclic AMP, the mechanism by which this occurs is poorly understood. The current study examined which signaling pathways are responsible for decreasing cyclic AMP in microglia following TNF-α stimulation and sought to identify the role cyclic AMP plays in regulating these pathways. In EOC2 microglia, TNF-α produced a dramatic reduction in cyclic AMP and increased cyclic AMP-dependent PDE activity that could be antagonized by Rolipram, myristoylated-PKI, PD98059, or JSH-23, implicating a role for PDE4, PKA, MEK, and NF-κB in this regulation. Following TNF-α there were significant increases in iNOS and COX-2 immunoreactivity, phosphorylated ERK1/2 and NF-κB-p65, IκB degradation, and NF-κB p65 nuclear translocation, which were reduced in the presence of high levels of cyclic AMP, indicating that reductions in cyclic AMP during cytokine stimulation are important for removing its inhibitory action on NF-κB activation and subsequent proinflammatory gene expression. Further elucidation of the signaling crosstalk involved in decreasing cyclic AMP in response to inflammatory signals may provide novel therapeutic targets for modulating microglial cell activation during neurological injury and disease.

  2. MW151 Inhibited IL-1β Levels after Traumatic Brain Injury with No Effect on Microglia Physiological Responses.

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    Adam D Bachstetter

    Full Text Available A prevailing neuroinflammation hypothesis is that increased production of proinflammatory cytokines contributes to progressive neuropathology, secondary to the primary damage caused by a traumatic brain injury (TBI. In support of the hypothesis, post-injury interventions that inhibit the proinflammatory cytokine surge can attenuate the progressive pathology. However, other post-injury neuroinflammatory responses are key to endogenous recovery responses. Therefore, it is critical that pharmacological attenuation of detrimental or dysregulated neuroinflammatory processes avoid pan-suppression of inflammation. MW151 is a CNS-penetrant, small molecule experimental therapeutic that restores injury- or disease-induced overproduction of proinflammatory cytokines towards homeostasis without immunosuppression. Post-injury administration of MW151 in a closed head injury model of mild TBI suppressed acute cytokine up-regulation and downstream cognitive impairment. Here, we report results from a diffuse brain injury model in mice using midline fluid percussion. Low dose (0.5-5.0 mg/kg administration of MW151 suppresses interleukin-1 beta (IL-1β levels in the cortex while sparing reactive microglia and astrocyte responses. To probe molecular mechanisms, we used live cell imaging of the BV-2 microglia cell line to demonstrate that MW151 does not affect proliferation, migration, or phagocytosis of the cells. Our results provide insight into the roles of glial responses to brain injury and indicate the feasibility of using appropriate dosing for selective therapeutic modulation of injurious IL-1β increases while sparing other glial responses to injury.

  3. The critical role of Nramp1 in degrading α-synuclein oligomers in microglia under iron overload condition.

    Science.gov (United States)

    Wu, Kuo-Chen; Liou, Horng-Huei; Kao, Yu-Han; Lee, Chih-Yu; Lin, Chun-Jung

    2017-08-01

    Oligomeric α-synuclein is a key mediator in the pathogenesis of Parkinson's disease (PD) and is mainly cleared by autophagy-lysosomal pathway, whose dysfunction results in the accumulation and cell-to-cell transmission of α-synuclein. In this study, concomitant with the accumulation of iron and oligomeric α-synuclein, higher expression of a lysosomal iron transporter, natural resistance-associated macrophage protein-1 (Nramp1), was observed in microglia in post-mortem striatum of sporadic PD patients. Using Nramp1-deficient macrophage (RAW264.7) and microglial (BV-2) cells as in-vitro models, iron exposure significantly reduced the degradation rate of the administered human α-synuclein oligomers, which can be restored by the expression of the wild-type, but not mutant (D543N), Nramp1. Likewise, under iron overload condition, mice with functional Nramp1 (DBA/2 and C57BL/6 congenic mice carrying functional Nramp1) had a better ability to degrade infused human α-synuclein oligomers than mice with nonfunctional Nramp1 (C57BL/6) in the brain and microglia. The interplay between iron and Nramp1 exhibited parallel effects on the clearance of α-synuclein and the activity of lysosomal cathepsin D in vitro and in vivo. Collectively, these findings suggest that the function of Nramp1 contributes to microglial degradation of oligomeric α-synuclein under iron overload condition and may be implicated in the pathogenesis of PD. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Neurodegeneration with inflammation is accompanied by accumulation of iron and ferritin in microglia and neurons.

    Science.gov (United States)

    Thomsen, Maj Schneider; Andersen, Michelle Vandborg; Christoffersen, Pia Rægaard; Jensen, Malene Duedal; Lichota, Jacek; Moos, Torben

    2015-09-01

    Chronic inflammation in the substantia nigra (SN) accompanies conditions with progressive neurodegeneration. This inflammatory process contributes to gradual iron deposition that may catalyze formation of free-radical mediated damage, hence exacerbating the neurodegeneration. This study examined proteins related to iron-storage (ferritin) and iron-export (ferroportin) (aka metal transporter protein 1, MTP1) in a model of neurodegeneration. Ibotenic acid injected stereotactically into the striatum leads to loss of GABAergic neurons projecting to SN pars reticulata (SNpr), which subsequently leads to excitotoxicity in the SNpr as neurons here become vulnerable to their additional glutamatergic projections from the subthalamic nucleus. This imbalance between glutamate and GABA eventually led to progressive shrinkage of the SNpr and neuronal loss. Neuronal cell death was accompanied by chronic inflammation as revealed by the presence of cells expressing ED1 and CD11b in the SNpr and the adjacent white matter mainly denoted by the crus cerebri. The SNpr also exhibited changes in iron metabolism seen as a marked accumulation of inflammatory cells containing ferric iron and ferritin with morphology corresponding to macrophages and microglia. Ferritin was detected in neurons of the lesioned SNpr in contrast to the non-injected side. Compared to non-injected rats, surviving neurons of the SNpr expressed ferroportin at unchanged level. Analyses of dissected SNpr using RT-qPCR showed a rise in ferritin-H and -L transcripts with increasing age but no change was observed in the lesioned side compared to the non-lesioned side, indicating that the increased expression of ferritin in the lesioned side occurred at the post-transcriptional level. Hepcidin transcripts were higher in the lesioned side in contrast to ferroportin mRNA that remained unaltered. The continuous entry of iron-containing inflammatory cells into the degenerating SNpr and their subsequent demise is probably

  5. Strategies to increase the activity of microglia as efficient protectors of the brain against infections

    Directory of Open Access Journals (Sweden)

    Roland eNau

    2014-05-01

    Full Text Available In healthy individuals, infections of the CNS are comparatively rare. Based on the ability of microglial cells to phagocytose and kill pathogens and on clinical findings in immunocompromized patients with CNS infections, we hypothesize that an intact microglial function is crucial to protect the brain from infections. Phagocytosis of pathogens by microglial cells can be stimulated by agonists of receptors of the innate immune system. Enhancing this pathway to increase the resistance of the brain to infections entails the risk of inducing collateral damage to the nervous tissue. The diversity of microglial cells opens avenue to selectively stimulate sub-populations responsible for the defence against pathogens without stimulating sub-populations which are responsible for collateral damage to the nervous tissue. Palmitoylethanolamide (PEA, an endogenous lipid, increased phagocytosis of bacteria by microglial cells in vitro without a measurable proinflammatory effect. It was tested clinically apparently without severe side effects. Glatiramer acetate increased phagocytosis of latex beads by microglia and monocytes, and dimethyl fumarate enhanced elimination of human immunodeficiency virus from infected macrophages without inducing a release of proinflammatory compounds. Therefore, the discovery of compounds which stimulate the elimination of pathogens without collateral damage of neuronal structures appears an achievable goal. PEA and, with limitations, glatiramer acetate and dimethyl fumarate appear promising candidates.

  6. Granulocyte-colony-stimulating factor (G-CSF) signaling in spinal microglia drives visceral sensitization following colitis.

    Science.gov (United States)

    Basso, Lilian; Lapointe, Tamia K; Iftinca, Mircea; Marsters, Candace; Hollenberg, Morley D; Kurrasch, Deborah M; Altier, Christophe

    2017-10-17

    Pain is a main symptom of inflammatory diseases and often persists beyond clinical remission. Although we have a good understanding of the mechanisms of sensitization at the periphery during inflammation, little is known about the mediators that drive central sensitization. Recent reports have identified hematopoietic colony-stimulating factors as important regulators of tumor- and nerve injury-associated pain. Using a mouse model of colitis, we identify the proinflammatory cytokine granulocyte-colony-stimulating factor (G-CSF or Csf-3) as a key mediator of visceral sensitization. We report that G-CSF is specifically up-regulated in the thoracolumbar spinal cord of colitis-affected mice. Our results show that resident spinal microglia express the G-CSF receptor and that G-CSF signaling mediates microglial activation following colitis. Furthermore, healthy mice subjected to intrathecal injection of G-CSF exhibit pronounced visceral hypersensitivity, an effect that is abolished by microglial depletion. Mechanistically, we demonstrate that G-CSF injection increases Cathepsin S activity in spinal cord tissues. When cocultured with microglia BV-2 cells exposed to G-CSF, dorsal root ganglion (DRG) nociceptors become hyperexcitable. Blocking CX3CR1 or nitric oxide production during G-CSF treatment reduces excitability and G-CSF-induced visceral pain in vivo. Finally, administration of G-CSF-neutralizing antibody can prevent the establishment of persistent visceral pain postcolitis. Overall, our work uncovers a DRG neuron-microglia interaction that responds to G-CSF by engaging Cathepsin S-CX3CR1-inducible NOS signaling. This interaction represents a central step in visceral sensitization following colonic inflammation, thereby identifying spinal G-CSF as a target for treating chronic abdominal pain.

  7. Toll-like receptor 9 is required for opioid-induced microglia apoptosis.

    Directory of Open Access Journals (Sweden)

    Lei He

    2011-04-01

    Full Text Available Opioids have been widely applied in clinics as one of the most potent pain relievers for centuries, but their abuse has deleterious physiological effects beyond addiction. However, the underlying mechanism by which microglia in response to opioids remains largely unknown. Here we show that morphine induces the expression of Toll-like receptor 9 (TLR9, a key mediator of innate immunity and inflammation. Interestingly, TLR9 deficiency significantly inhibited morphine-induced apoptosis in microglia. Similar results were obtained when endogenous TLR9 expression was suppressed by the TLR9 inhibitor CpGODN. Inhibition of p38 MAPK by its specific inhibitor SB203580 attenuated morphine-induced microglia apoptosis in wild type microglia. Morphine caused a dramatic decrease in Bcl-2 level but increase in Bax level in wild type microglia, but not in TLR9 deficient microglia. In addition, morphine treatment failed to induce an increased levels of phosphorylated p38 MAPK and MAP kinase kinase 3/6 (MKK3/6, the upstream MAPK kinase of p38 MAPK, in either TLR9 deficient or µ-opioid receptor (µOR deficient primary microglia, suggesting an involvement of MAPK and µOR in morphine-mediated TLR9 signaling. Moreover, morphine-induced TLR9 expression and microglia apoptosis appears to require μOR. Collectively, these results reveal that opioids prime microglia to undergo apoptosis through TLR9 and µOR as well. Taken together, our data suggest that inhibition of TLR9 and/or blockage of µOR is capable of preventing opioid-induced brain damage.

  8. Low-Fat Diet With Caloric Restriction Reduces White Matter Microglia Activation During Aging

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    Zhuoran Yin

    2018-03-01

    Full Text Available Rodent models of both aging and obesity are characterized by inflammation in specific brain regions, notably the corpus callosum, fornix, and hypothalamus. Microglia, the resident macrophages of the central nervous system, are important for brain development, neural support, and homeostasis. However, the effects of diet and lifestyle on microglia during aging are only partly understood. Here, we report alterations in microglia phenotype and functions in different brain regions of mice on a high-fat diet (HFD or low-fat diet (LFD during aging and in response to voluntary running wheel exercise. We compared the expression levels of genes involved in immune response, phagocytosis, and metabolism in the hypothalamus of 6-month-old HFD and LFD mice. We also compared the immune response of microglia from HFD or LFD mice to peripheral inflammation induced by intraperitoneal injection of lipopolysaccharide (LPS. Finally, we investigated the effect of diet, physical exercise, and caloric restriction (40% reduction compared to ad libitum intake on microglia in 24-month-old HFD and LFD mice. Changes in diet caused morphological changes in microglia, but did not change the microglia response to LPS-induced systemic inflammation. Expression of phagocytic markers (i.e., Mac-2/Lgals3, Dectin-1/Clec7a, and CD16/CD32 in the white matter microglia of 24-month-old brain was markedly decreased in calorically restricted LFD mice. In conclusion, LFD resulted in reduced activation of microglia, which might be an underlying mechanism for the protective role of caloric restriction during aging-associated decline.

  9. Low-Fat Diet With Caloric Restriction Reduces White Matter Microglia Activation During Aging.

    Science.gov (United States)

    Yin, Zhuoran; Raj, Divya D; Schaafsma, Wandert; van der Heijden, Roel A; Kooistra, Susanne M; Reijne, Aaffien C; Zhang, Xiaoming; Moser, Jill; Brouwer, Nieske; Heeringa, Peter; Yi, Chun-Xia; van Dijk, Gertjan; Laman, Jon D; Boddeke, Erik W G M; Eggen, Bart J L

    2018-01-01

    Rodent models of both aging and obesity are characterized by inflammation in specific brain regions, notably the corpus callosum, fornix, and hypothalamus. Microglia, the resident macrophages of the central nervous system, are important for brain development, neural support, and homeostasis. However, the effects of diet and lifestyle on microglia during aging are only partly understood. Here, we report alterations in microglia phenotype and functions in different brain regions of mice on a high-fat diet (HFD) or low-fat diet (LFD) during aging and in response to voluntary running wheel exercise. We compared the expression levels of genes involved in immune response, phagocytosis, and metabolism in the hypothalamus of 6-month-old HFD and LFD mice. We also compared the immune response of microglia from HFD or LFD mice to peripheral inflammation induced by intraperitoneal injection of lipopolysaccharide (LPS). Finally, we investigated the effect of diet, physical exercise, and caloric restriction (40% reduction compared to ad libitum intake) on microglia in 24-month-old HFD and LFD mice. Changes in diet caused morphological changes in microglia, but did not change the microglia response to LPS-induced systemic inflammation. Expression of phagocytic markers (i.e., Mac-2/Lgals3, Dectin-1/Clec7a, and CD16/CD32) in the white matter microglia of 24-month-old brain was markedly decreased in calorically restricted LFD mice. In conclusion, LFD resulted in reduced activation of microglia, which might be an underlying mechanism for the protective role of caloric restriction during aging-associated decline.

  10. Involvement of microglia activation in the lead induced long-term potentiation impairment.

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    Ming-Chao Liu

    Full Text Available Exposure of Lead (Pb, a known neurotoxicant, can impair spatial learning and memory probably via impairing the hippocampal long-term potentiation (LTP as well as hippocampal neuronal injury. Activation of hippocampal microglia also impairs spatial learning and memory. Thus, we raised the hypothesis that activation of microglia is involved in the Pb exposure induced hippocampal LTP impairment and neuronal injury. To test this hypothesis and clarify its underlying mechanisms, we investigated the Pb-exposure on the microglia activation, cytokine release, hippocampal LTP level as well as neuronal injury in in vivo or in vitro model. The changes of these parameters were also observed after pretreatment with minocycline, a microglia activation inhibitor. Long-term low dose Pb exposure (100 ppm for 8 weeks caused significant reduction of LTP in acute slice preparations, meanwhile, such treatment also significantly increased hippocampal microglia activation as well as neuronal injury. In vitro Pb-exposure also induced significantly increase of microglia activation, up-regulate the release of cytokines including tumor necrosis factor-alpha (TNF-α, interleukin-1β (IL-1β and inducible nitric oxide synthase (iNOS in microglia culture alone as well as neuronal injury in the co-culture with hippocampal neurons. Inhibiting the microglia activation with minocycline significantly reversed the above-mentioned Pb-exposure induced changes. Our results showed that Pb can cause microglia activation, which can up-regulate the level of IL-1β, TNF-α and iNOS, these proinflammatory factors may cause hippocampal neuronal injury as well as LTP deficits.

  11. Persistent activation of microglia is associated with neuronal dysfunction of callosal projecting pathways and multiple sclerosis-like lesions in relapsing--remitting experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Rasmussen, Stine; Wang, Yue; Kivisäkk, Pia

    2007-01-01

    callosal projecting neurons. There was significant impairment of retrograde labeling of NeuN-positive callosal projecting neurons and reduction in the labelling of their transcallosal axons. These data demonstrate a novel paradigm of cortical and callosal neuropathology in a mouse model of MS, perpetuated......Cortical pathology, callosal atrophy and axonal loss are substrates of progression in multiple sclerosis (MS). Here we describe cortical, periventricular subcortical lesions and callosal demyelination in relapsing-remitting experimental autoimmune encephalomyelitis in SJL mice that are similar...... to lesions found in MS. Unlike the T-cell infiltrates that peak during acute disease, we found that microglia activation persists through the chronic disease phase. Microglia activation correlated with abnormal phosphorylation of neurofilaments in the cortex and stripping of synaptic proteins in cortical...

  12. A local anesthetic, ropivacaine, suppresses activated microglia via a nerve growth factor-dependent mechanism and astrocytes via a nerve growth factor-independent mechanism in neuropathic pain

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    Sakamoto Atsuhiro

    2011-01-01

    Full Text Available Abstract Background Local anesthetics alleviate neuropathic pain in some cases in clinical practice, and exhibit longer durations of action than those predicted on the basis of the pharmacokinetics of their blocking effects on voltage-dependent sodium channels. Therefore, local anesthetics may contribute to additional mechanisms for reversal of the sensitization of nociceptive pathways that occurs in the neuropathic pain state. In recent years, spinal glial cells, microglia and astrocytes, have been shown to play critical roles in neuropathic pain, but their participation in the analgesic effects of local anesthetics remains largely unknown. Results Repetitive epidural administration of ropivacaine reduced the hyperalgesia induced by chronic constrictive injury of the sciatic nerve. Concomitantly with this analgesia, ropivacaine suppressed the increases in the immunoreactivities of CD11b and glial fibrillary acidic protein in the dorsal spinal cord, as markers of activated microglia and astrocytes, respectively. In addition, epidural administration of a TrkA-IgG fusion protein that blocks the action of nerve growth factor (NGF, which was upregulated by ropivacaine in the dorsal root ganglion, prevented the inhibitory effect of ropivacaine on microglia, but not astrocytes. The blockade of NGF action also abolished the analgesic effect of ropivacaine on neuropathic pain. Conclusions Ropivacaine provides prolonged analgesia possibly by suppressing microglial activation in an NGF-dependent manner and astrocyte activation in an NGF-independent manner in the dorsal spinal cord. Local anesthetics, including ropivacaine, may represent a new approach for glial cell inhibition and, therefore, therapeutic strategies for neuropathic pain.

  13. Modulation of microglia in the retina: new insights into diabetic retinopathy.

    Science.gov (United States)

    Arroba, Ana I; Valverde, Ángela M

    2017-06-01

    During last decades, the diagnosis of diabetes has been associated with several chronic complications such as diabetic retinopathy (DR). Recent studies of DR have revealed an inflammatory component, which precedes the detection of alterations in the visual function. During DR, the inflammatory process presents two opposite roles depending on the polarization of resident immune cells of the retina triggering proinflammatory (M1) or antiinflammatory (M2) actions. In an early stage of DR, the M2 response concurs with the M1 and is able to ameliorate inflammation and delay the progression of the disease. However, during the progression of DR, the M1 response is maintained whereas the M2 declines and, in this scenario, the classical proinflammatory signaling pathways are chronically activated leading to retinal neurodegeneration and the loss of visual function. The M1/M2 responses are closely related to the activation and polarization of microglial cells. This review aims to offer an overview of the recent insights into the role of microglial cells during inflammation in DR. We have focused on the possibility of modulating microglia polarization as a new therapeutic strategy in DR treatments.

  14. Quinolinic acid neurotoxicity: Differential roles of astrocytes and microglia via FGF-2-mediated signaling in redox-linked cytoskeletal changes.

    Science.gov (United States)

    Pierozan, Paula; Biasibetti, Helena; Schmitz, Felipe; Ávila, Helena; Parisi, Mariana M; Barbe-Tuana, Florencia; Wyse, Angela T S; Pessoa-Pureur, Regina

    2016-12-01

    QUIN is a glutamate agonist playing a role in the misregulation of the cytoskeleton, which is associated with neurodegeneration in rats. In this study, we focused on microglial activation, FGF2/Erk signaling, gap junctions (GJs), inflammatory parameters and redox imbalance acting on cytoskeletal dynamics of the in QUIN-treated neural cells of rat striatum. FGF-2/Erk signaling was not altered in QUIN-treated primary astrocytes or neurons, however cytoskeleton was disrupted. In co-cultured astrocytes and neurons, QUIN-activated FGF2/Erk signaling prevented the cytoskeleton from remodeling. In mixed cultures (astrocyte, neuron, microglia), QUIN-induced FGF-2 increased level failed to activate Erk and promoted cytoskeletal destabilization. The effects of QUIN in mixed cultures involved redox imbalance upstream of Erk activation. Decreased connexin 43 (Cx43) immunocontent and functional GJs, was also coincident with disruption of the cytoskeleton in primary astrocytes and mixed cultures. We postulate that in interacting astrocytes and neurons the cytoskeleton is preserved against the insult of QUIN by activation of FGF-2/Erk signaling and proper cell-cell interaction through GJs. In mixed cultures, the FGF-2/Erk signaling is blocked by the redox imbalance associated with microglial activation and disturbed cell communication, disrupting the cytoskeleton. Thus, QUIN signal activates differential mechanisms that could stabilize or destabilize the cytoskeleton of striatal astrocytes and neurons in culture, and glial cells play a pivotal role in these responses preserving or disrupting a combination of signaling pathways and cell-cell interactions. Taken together, our findings shed light into the complex role of the active interaction of astrocytes, neurons and microglia in the neurotoxicity of QUIN. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Gestational Exposure to Air Pollution Alters Cortical Volume, Microglial Morphology, and Microglia-Neuron Interactions in a Sex-Specific Manner

    Directory of Open Access Journals (Sweden)

    Jessica L. Bolton

    2017-05-01

    Full Text Available Microglia are the resident immune cells of the brain, important for normal neural development in addition to host defense in response to inflammatory stimuli. Air pollution is one of the most pervasive and harmful environmental toxicants in the modern world, and several large scale epidemiological studies have recently linked prenatal air pollution exposure with an increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD. Diesel exhaust particles (DEP are a primary toxic component of air pollution, and markedly activate microglia in vitro and in vivo in adult rodents. We have demonstrated that prenatal exposure to DEP in mice, i.e., to the pregnant dams throughout gestation, results in a persistent vulnerability to behavioral deficits in adult offspring, especially in males, which is intriguing given the greater incidence of ASD in males to females (∼4:1. Moreover, there is a striking upregulation of toll-like receptor (TLR 4 gene expression within the brains of the same mice, and this expression is primarily in microglia. Here we explored the impact of gestational exposure to DEP or vehicle on microglial morphology in the developing brains of male and female mice. DEP exposure increased inflammatory cytokine protein and altered the morphology of microglia, consistent with activation or a delay in maturation, only within the embryonic brains of male mice; and these effects were dependent on TLR4. DEP exposure also increased cortical volume at embryonic day (E18, which switched to decreased volume by post-natal day (P30 in males, suggesting an impact on the developing neural stem cell niche. Consistent with this hypothesis, we found increased microglial-neuronal interactions in male offspring that received DEP compared to all other groups. Taken together, these data suggest a mechanism by which prenatal exposure to environmental toxins may affect microglial development and long-term function, and thereby contribute

  16. Progesterone therapy induces an M1 to M2 switch in microglia phenotype and suppresses NLRP3 inflammasome in a cuprizone-induced demyelination mouse model.

    Science.gov (United States)

    Aryanpour, Roya; Pasbakhsh, Parichehr; Zibara, Kazem; Namjoo, Zeinab; Beigi Boroujeni, Fatemeh; Shahbeigi, Saeed; Kashani, Iraj Ragerdi; Beyer, Cordian; Zendehdel, Adib

    2017-10-01

    Demyelination of the central nervous system (CNS) has been associated to reactive microglia in neurodegenerative disorders, such as multiple sclerosis (MS). The M1 microglia phenotype plays a pro-inflammatory role while M2 is involved in anti-inflammatory processes in the brain. In this study, CPZ-induced demyelination mouse model was used to investigate the effect of progesterone (PRO) therapy on microglia activation and neuro-inflammation. Results showed that progesterone therapy (CPZ+PRO) decreased neurological behavioral deficits, as demonstrated by significantly decreased escape latencies, in comparison to CPZ mice. In addition, CPZ+PRO caused a significant reduction in the mRNA expression levels of M1-markers (iNOS, CD86, MHC-II and TNF-α) in the corpus callosum region, whereas the expression of M2-markers (Trem-2, CD206, Arg-1 and TGF-β) was significantly increased, in comparison to CPZ mice. Moreover, CPZ+PRO resulted in a significant decrease in the number of iNOS + and Iba-1 + /iNOS + cells (M1), whereas TREM-2 + and Iba-1 + /TREM-2 + cells (M2) significantly increased, in comparison to CPZ group. Furthermore, CPZ+PRO caused a significant decrease in mRNA and protein expression levels of NLRP3 and IL-18 (~2-fold), in comparison to the CPZ group. Finally, CPZ+PRO therapy was accompanied with reduced levels of demyelination, compared to CPZ, as confirmed by immunofluorescence to myelin basic protein (MBP) and Luxol Fast Blue (LFB) staining, as well as transmission electron microscopy (TEM) analysis. In summary, we reported for the first time that PRO therapy causes polarization of M2 microglia, attenuation of M1 phenotype, and suppression of NLRP3 inflammasome in a CPZ-induced demyelination model of MS. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Extended magnetic resonance imaging studies on the effect of classically activated microglia transplantation on white matter regeneration following spinal cord focal injury in adult rats

    Science.gov (United States)

    Marcol, Wiesław; Ślusarczyk, Wojciech; Larysz-Brysz, Magdalena; Łabuzek, Krzysztof; Kapustka, Bartosz; Staszkiewicz, Rafał; Rosicka, Paulina; Kalita, Katarzyna; Węglarz, Władysław; Lewin-Kowalik, Joanna

    2017-01-01

    Spinal cord injuries are still a serious problem for regenerative medicine. Previous research has demonstrated that activated microglia accumulate in spinal lesions, influencing the injured tissues in various ways. Therefore, transplantation of activated microglia may have a beneficial role in the regeneration of the nervous system. The present study examined the influence of transplanted activated microglial cells in adult rats with injured spinal cords. Rats were randomly divided into an experimental (M) and control (C) group, and were subjected to non-laminectomy focal injury of spinal cord white matter by means of a high-pressured air stream. In group M, activated cultured microglial cells were injected twice into the site of injury. Functional outcome and morphological features of regeneration were analyzed during a 12-week follow-up. The lesions were characterized by means of magnetic resonance imaging (MRI). Neurons in the brain stem and motor cortex were labeled with FluoroGold (FG). A total of 12 weeks after surgery, spinal cords and brains were collected and subjected to histopathological and immunohistochemical examinations. Lesion sizes in the spinal cord were measured and the number of FG-positive neurons was counted. Rats in group M demonstrated significant improvement of locomotor performance when compared with group C (PMRI analysis demonstrated moderate improvement in water diffusion along the spinal cord in the group M following microglia treatment, as compared with group C. The water diffusion perpendicular to the spinal cord in group M was closer to the reference values for a healthy spinal cord than it was in group C. The sizes of lesions were also significantly smaller in group M than in the group C (P<0.05). The number of brain stem and motor cortex FG-positive neurons in group M was significantly higher than in group C. The present study demonstrated that delivery of activated microglia directly into the injured spinal cord gives some

  18. A homologous form of human interleukin 16 is implicated in microglia recruitment following nervous system injury in leech Hirudo medicinalis.

    Science.gov (United States)

    Croq, Françoise; Vizioli, Jacopo; Tuzova, Marina; Tahtouh, Muriel; Sautiere, Pierre-Eric; Van Camp, Christelle; Salzet, Michel; Cruikshank, William W; Pestel, Joel; Lefebvre, Christophe

    2010-11-01

    In contrast to mammals, the medicinal leech Hirudo medicinalis can completely repair its central nervous system (CNS) after injury. This invertebrate model offers unique opportunities to study the molecular and cellular basis of the CNS repair processes. When the leech CNS is injured, microglial cells migrate and accumulate at the site of lesion, a phenomenon known to be essential for the usual sprouting of injured axons. In the present study, we demonstrate that a new molecule, designated HmIL-16, having functional homologies with human interleukin-16 (IL-16), has chemotactic activity on leech microglial cells as observed using a gradient of human IL-16. Preincubation of microglial cells either with an anti-human IL-16 antibody or with anti-HmIL-16 antibody significantly reduced microglia migration induced by leech-conditioned medium. Functional homology was demonstrated further by the ability of HmIL-16 to promote human CD4+ T cell migration which was inhibited by antibody against human IL-16, an IL-16 antagonist peptide or soluble CD4. Immunohistochemistry of leech CNS indicates that HmIL-16 protein present in the neurons is rapidly transported and stored along the axonal processes to promote the recruitment of microglial cells to the injured axons. To our knowledge, this is the first identification of a functional interleukin-16 homologue in invertebrate CNS. The ability of HmIL-16 to recruit microglial cells to sites of CNS injury suggests a role for HmIL-16 in the crosstalk between neurons and microglia in the leech CNS repair.

  19. Depletion of microglia and inhibition of exosome synthesis halt tau propagation

    Science.gov (United States)

    Asai, Hirohide; Ikezu, Seiko; Tsunoda, Satoshi; Medalla, Maria; Luebke, Jennifer; Haydar, Tarik; Wolozin, Benjamin; Butovsky, Oleg; Kügler, Sebastian; Ikezu, Tsuneya

    2015-01-01

    Accumulation of pathological tau protein is a major hallmark of Alzheimer’s disease. Tau protein spreads from the entorhinal cortex to the hippocampal region early in the disease. Microglia, the primary phagocytes in the brain, are positively correlated with tau pathology, but their involvement in tau propagation is unknown. We developed an adeno-associated virus–based model exhibiting rapid tau propagation from the entorhinal cortex to the dentate gyrus in 4 weeks. We found that depleting microglia dramatically suppressed the propagation of tau and reduced excitability in the dentate gyrus in this mouse model. Moreover, we demonstrate that microglia spread tau via exosome secretion, and inhibiting exosome synthesis significantly reduced tau propagation in vitro and in vivo. These data suggest that microglia and exosomes contribute to the progression of tauopathy and that the exosome secretion pathway may be a therapeutic target. PMID:26436904

  20. Low-Fat Diet With Caloric Restriction Reduces White Matter Microglia Activation During Aging

    NARCIS (Netherlands)

    Yin, Zhuoran; Raj, Divya D.; Schaafsma, Wandert; van der Heijden, Roel A.; Kooistra, Susanne M.; Reijne, Aaffien C.; Zhang, Xiaoming; Moser, Jill; Brouwer, Nieske; Heeringa, Peter; Yi, Chun-Xia; van Dijk, Gertjan; Laman, Jon D.; Boddeke, Erik W. G. M.; Eggen, Bart J. L.

    2018-01-01

    Rodent models of both aging and obesity are characterized by inflammation in specific brain regions, notably the corpus callosum, fornix, and hypothalamus. Microglia, the resident macrophages of the central nervous system, are important for brain development, neural support, and homeostasis.

  1. Treating Gulf War Illness with Novel Anti-Inflammatories: A Screening of Botantical Microglia Modulators

    Science.gov (United States)

    2016-10-01

    AWARD NUMBER: W81XWH-14-1-0623 TITLE: Treating Gulf War Illness with Novel Anti-Inflammatories: A Screening of Botantical Microglia Modulators...Report 3. DATES COVERED 30 Sep 2015 - 29 Sep 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Treating Gulf War Illness with Novel Anti...SUBJECT TERMS Gulf War Illness, botanical, anti-inflammatory, biomarker, microglia, improvement, treatment 16. SECURITY CLASSIFICATION OF: 17

  2. From development to dysfunction: microglia and the complement cascade in CNS homeostasis.

    Science.gov (United States)

    Zabel, Matthew K; Kirsch, Wolff M

    2013-06-01

    Of the many mysteries that surround the brain, few surpass the awe-inspiring complexity of its development. The intricate wiring of the brain at both the system and molecular level is both spatially and temporally regulated in perfect synchrony. How such a delicate, yet elegant, system arises from an embryo's most basic cells remains at the forefront of neuroscientific research. At the cellular level, the competitive dance between synapses struggling to gain dominance seems to be refereed by both neurons themselves and microglia, the innate immune cells of the nervous system. Additionally, the unexpected complement cascade, a major effecter arm of the innate immune system, is almost certainly involved in synaptic remodeling by tagging destined neurons and synapses for destruction. As suddenly as they appear, the mechanisms of neurogenesis recede entering into adulthood. However, with age and insult, these mechanisms boisterously return, resulting in neurodegeneration. This review describes some of the mechanisms involved in synaptogenesis and wiring of the brain from the point of view of the innate immune system and then covers how similar molecular processes return with age and disease, specifically in the context of Alzheimer's disease. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Degradation of Alzheimer's amyloid fibrils by microglia requires delivery of ClC-7 to lysosomes

    Science.gov (United States)

    Majumdar, Amitabha; Capetillo-Zarate, Estibaliz; Cruz, Dana; Gouras, Gunnar K.; Maxfield, Frederick R.

    2011-01-01

    Incomplete lysosomal acidification in microglia inhibits the degradation of fibrillar forms of Alzheimer's amyloid β peptide (fAβ). Here we show that in primary microglia a chloride transporter, ClC-7, is not delivered efficiently to lysosomes, causing incomplete lysosomal acidification. ClC-7 protein is synthesized by microglia but it is mistargeted and appears to be degraded by an endoplasmic reticulum–associated degradation pathway. Activation of microglia with macrophage colony-stimulating factor induces trafficking of ClC-7 to lysosomes, leading to lysosomal acidification and increased fAβ degradation. ClC-7 associates with another protein, Ostm1, which plays an important role in its correct lysosomal targeting. Expression of both ClC-7 and Ostm1 is increased in activated microglia, which can account for the increased delivery of ClC-7 to lysosomes. Our findings suggest a novel mechanism of lysosomal pH regulation in activated microglia that is required for fAβ degradation. PMID:21441306

  4. Spinal microglia: A potential target in the treatment of chronic visceral pain

    Directory of Open Access Journals (Sweden)

    Ching-Liang Lu

    2014-01-01

    Full Text Available Chronic visceral pain is the predominant symptom of functional gastrointestinal disorders and chronic pancreatitis. Such pain can impair the patients' quality of life, and can also serve as one of the principal reasons for these patients to seek medical help. Nevertheless, the underlying mechanisms of chronic visceral pain have remained unclear, and much of what we know about visceral pain has been derived from studies of somatic nociception. Current treatment of chronic visceral pain has continued to be unsatisfactory, because of unclear pathophysiology. However, recent progress in pain research has identified the important role of spinal microglia in the development of somatic nociception. For visceral pain, several animal studies have demonstrated that spinal cord microglia is activated during the development of visceral hyperalgesia, which can be induced by neonatal colorectal irritation, psychological stress, and trinitrobenzene sulfonic acid-induced pancreatitis. This visceral hyperalgesia is also associated with elevated phosphorylation of p38 mitogen-activated protein kinase. Minocycline (a microglia inhibitor reversed the hyperalgesia in rat models of chronic visceral pain, whereas fractalkine (FKN, a microglia activator reproduced the visceral nociception in naïve rats. These preliminary results support the pronociceptive role of spinal microglia in mediating visceral hyperalgesia. Consequently, spinal microglia may serve as a promising target for controlling the chronic visceral pain.

  5. The "Big-Bang" for modern glial biology: Translation and comments on Pío del Río-Hortega 1919 series of papers on microglia.

    Science.gov (United States)

    Sierra, Amanda; de Castro, Fernando; Del Río-Hortega, Juan; Rafael Iglesias-Rozas, José; Garrosa, Manuel; Kettenmann, Helmut

    2016-11-01

    The word "glia" was coined in the mid-19th century and defined as "the nerve glue". For decades, it was assumed to be a uniform matrix, until cell theorists raised the "neuron doctrine" which stipulated that nervous tissue was composed of individual cells. The term "astrocytes" was introduced in the late 19th century as a synonym for glial cells, but it was Santiago Ramón y Cajal who defined a "third element" distinct from glial cells (astrocytes) and neurons. It was not until 1919 when Pío del Río-Hortega, an alumnus of the Cajal School, introduced the modern terms we use today, and thoroughly described both "oligodendrocytes" and "microglia" to clearly distinguish them from astrocytes. In a series of four papers published that year in Spanish, Río-Hortega described the distribution and morphological phenotype of microglia. He also noted that these cells were the origin of the rod cells described earlier in pathologic tissue, and recognized that resting microglia transformed into an ameboid phenotype in different types of brain diseases and pathologies. He also noted the mesodermal origin of these cells and recognized their phagocytic capacity. We here provide the first English translation of these landmark series of papers, which paved the way for modern glial research. To heighten the value and accessibility of these classic papers and their original figures, an introduction to this critical period of neuroscience is provided, along with unpublished photographs. By adding comments to the translated text, we provide sufficient context so that contemporary scientists may fully appreciate it. GLIA 2016;64:1801-1840. © 2016 Wiley Periodicals, Inc.

  6. Amyloid β oligomers induce interleukin-1β production in primary microglia in a cathepsin B- and reactive oxygen species-dependent manner

    Energy Technology Data Exchange (ETDEWEB)

    Taneo, Jun; Adachi, Takumi [Department of Animal Development and Physiology, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto 606-8501 (Japan); Yoshida, Aiko; Takayasu, Kunio [Responses to Environmental Signals and Stresses, Graduate School of Biostudies, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto, Kyoto 606-8501 (Japan); Takahara, Kazuhiko, E-mail: ktakahar@zoo.zool.kyoto-u.ac.jp [Department of Animal Development and Physiology, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto 606-8501 (Japan); Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Tokyo 102-0081 (Japan); Inaba, Kayo [Department of Animal Development and Physiology, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto 606-8501 (Japan); Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Tokyo 102-0081 (Japan)

    2015-03-13

    Amyloid β (Aβ) peptide, a causative agent of Alzheimer's disease, forms two types of aggregates: oligomers and fibrils. These aggregates induce inflammatory responses, such as interleukin-1β (IL-1β) production by microglia, which are macrophage-like cells located in the brain. In this study, we examined the effect of the two forms of Aβ aggregates on IL-1β production in mouse primary microglia. We prepared Aβ oligomer and fibril from Aβ (1–42) peptide in vitro. We analyzed the characteristics of these oligomers and fibrils by electrophoresis and atomic force microscopy. Interestingly, Aβ oligomers but not Aβ monomers or fibrils induced robust IL-1β production in the presence of lipopolysaccharide. Moreover, Aβ oligomers induced endo/phagolysosome rupture, which released cathepsin B into the cytoplasm. Aβ oligomer-induced IL-1β production was inhibited not only by the cathepsin B inhibitor CA-074-Me but also by the reactive oxygen species (ROS) inhibitor N-acetylcysteine. Random chemical crosslinking abolished the ability of the oligomers to induce IL-1β. Thus, multimerization and fibrillization causes Aβ oligomers to lose the ability to induce IL-1β. These results indicate that Aβ oligomers, but not fibrils, induce IL-1β production in primary microglia in a cathepsin B- and ROS-dependent manner. - Highlights: • We prepared amyloid β (Aβ) fibrils with minimum contamination of Aβ oligomers. • Primary microglia (MG) produced IL-1β in response to Aβ oligomers, but not fibrils. • Only Aβ oligomers induced leakage of cathepsin B from endo/phagolysosomes. • IL-1β production in response to Aβ oligomers depended on both cathepsin B and ROS. • Crosslinking reduced the ability of the Aβ oligomers to induce IL-1β from MG.

  7. Nucleotide transmitters ATP and ADP mediate intercellular calcium wave communication via P2Y12/13 receptors among BV-2 microglia.

    Directory of Open Access Journals (Sweden)

    Pengchong Jiang

    Full Text Available Nerve injury is accompanied by a liberation of diverse nucleotides, some of which act as 'find/eat-me' signals in mediating neuron-glial interplay. Intercellular Ca2+ wave (ICW communication is the main approach by which glial cells interact and coordinate with each other to execute immune defense. However, the detailed mechanisms on how these nucleotides participate in ICW communication remain largely unclear. In the present work, we employed a mechanical stimulus to an individual BV-2 microglia to simulate localized injury. Remarkable ICW propagation was observed no matter whether calcium was in the environment or not. Apyrase (ATP/ADP-hydrolyzing enzyme, suramin (broad-spectrum P2 receptor antagonist, 2-APB (IP3 receptor blocker and thapsigargin (endoplasmic reticulum calcium pump inhibitor potently inhibited these ICWs, respectively, indicating the dependence of nucleotide signals and P2Y receptors. Then, we detected the involvement of five naturally occurring nucleotides (ATP, ADP, UTP, UDP and UDP-glucose by desensitizing receptors. Results showed that desensitization with ATP and ADP could block ICW propagation in a dose-dependent manner, whereas other nucleotides had little effect. Meanwhile, the expression of P2Y receptors in BV-2 microglia was identified and their contributions were analyzed, from which we suggested P2Y12/13 receptors activation mostly contributed to ICWs. Besides, we estimated that extracellular ATP and ADP concentration sensed by BV-2 microglia was about 0.3 μM during ICWs by analyzing calcium dynamic characteristics. Taken together, these results demonstrated that the nucleotides ATP and ADP were predominant signal transmitters in mechanical stimulation-induced ICW communication through acting on P2Y12/13 receptors in BV-2 microglia.

  8. TRPM2 Channel Aggravates CNS Inflammation and Cognitive Impairment via Activation of Microglia in Chronic Cerebral Hypoperfusion.

    Science.gov (United States)

    Miyanohara, Jun; Kakae, Masashi; Nagayasu, Kazuki; Nakagawa, Takayuki; Mori, Yasuo; Arai, Ken; Shirakawa, Hisashi; Kaneko, Shuji

    2018-04-04

    Chronic cerebral hypoperfusion is a characteristic seen in widespread CNS diseases, including neurodegenerative and mental disorders, and is commonly accompanied by cognitive impairment. Recently, several studies demonstrated that chronic cerebral hypoperfusion can induce the excessive inflammatory responses that precede neuronal dysfunction; however, the precise mechanism of cognitive impairment due to chronic cerebral hypoperfusion remains unknown. Transient receptor potential melastatin 2 (TRPM2) is a Ca 2+ -permeable channel that is abundantly expressed in immune cells and is involved in aggravation of inflammatory responses. Therefore, we investigated the pathophysiological role of TRPM2 in a mouse chronic cerebral hypoperfusion model with bilateral common carotid artery stenosis (BCAS). When male mice were subjected to BCAS, cognitive dysfunction and white matter injury at day 28 were significantly improved in TRPM2 knock-out (TRPM2-KO) mice compared with wild-type (WT) mice, whereas hippocampal damage was not observed. There were no differences in blood-brain barrier breakdown and H 2 O 2 production between the two genotypes at 14 and 28 d after BCAS. Cytokine production was significantly suppressed in BCAS-operated TRPM2-KO mice compared with WT mice at day 28. In addition, the number of Iba1-positive cells gradually decreased from day 14. Moreover, daily treatment with minocycline significantly improved cognitive perturbation. Surgical techniques using bone marrow chimeric mice revealed that activated Iba1-positive cells in white matter could be brain-resident microglia, not peripheral macrophages. Together, these findings suggest that microglia contribute to the aggravation of cognitive impairment by chronic cerebral hypoperfusion, and that TRPM2 may be a potential target for chronic cerebral hypoperfusion-related disorders. SIGNIFICANCE STATEMENT Chronic cerebral hypoperfusion is manifested in a wide variety of CNS diseases, including neurodegenerative

  9. Brain-derived neurotrophic factor (BDNF) induces sustained intracellular Ca2+ elevation through the up-regulation of surface transient receptor potential 3 (TRPC3) channels in rodent microglia.

    Science.gov (United States)

    Mizoguchi, Yoshito; Kato, Takahiro A; Seki, Yoshihiro; Ohgidani, Masahiro; Sagata, Noriaki; Horikawa, Hideki; Yamauchi, Yusuke; Sato-Kasai, Mina; Hayakawa, Kohei; Inoue, Ryuji; Kanba, Shigenobu; Monji, Akira

    2014-06-27

    Microglia are immune cells that release factors, including proinflammatory cytokines, nitric oxide (NO), and neurotrophins, following activation after disturbance in the brain. Elevation of intracellular Ca(2+) concentration ([Ca(2+)]i) is important for microglial functions such as the release of cytokines and NO from activated microglia. There is increasing evidence suggesting that pathophysiology of neuropsychiatric disorders is related to the inflammatory responses mediated by microglia. Brain-derived neurotrophic factor (BDNF) is a neurotrophin well known for its roles in the activation of microglia as well as in pathophysiology and/or treatment of neuropsychiatric disorders. In this study, we sought to examine the underlying mechanism of BDNF-induced sustained increase in [Ca(2+)]i in rodent microglial cells. We observed that canonical transient receptor potential 3 (TRPC3) channels contribute to the maintenance of BDNF-induced sustained intracellular Ca(2+) elevation. Immunocytochemical technique and flow cytometry also revealed that BDNF rapidly up-regulated the surface expression of TRPC3 channels in rodent microglial cells. In addition, pretreatment with BDNF suppressed the production of NO induced by tumor necrosis factor α (TNFα), which was prevented by co-adiministration of a selective TRPC3 inhibitor. These suggest that BDNF induces sustained intracellular Ca(2+) elevation through the up-regulation of surface TRPC3 channels and TRPC3 channels could be important for the BDNF-induced suppression of the NO production in activated microglia. We show that TRPC3 channels could also play important roles in microglial functions, which might be important for the regulation of inflammatory responses and may also be involved in the pathophysiology and/or the treatment of neuropsychiatric disorders. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Microglia and neurons in the hippocampus of migratory sandpipers

    Directory of Open Access Journals (Sweden)

    C.G. Diniz

    2016-01-01

    Full Text Available The semipalmated sandpiper Calidris pusilla and the spotted sandpiper Actitis macularia are long- and short-distance migrants, respectively. C. pusilla breeds in the sub-arctic and mid-arctic tundra of Canada and Alaska and winters on the north and east coasts of South America. A. macularia breeds in a broad distribution across most of North America from the treeline to the southern United States. It winters in the southern United States, and Central and South America. The autumn migration route of C. pusilla includes a non-stop flight over the Atlantic Ocean, whereas autumn route of A. macularia is largely over land. Because of this difference in their migratory paths and the visuo-spatial recognition tasks involved, we hypothesized that hippocampal volume and neuronal and glial numbers would differ between these two species. A. macularia did not differ from C. pusilla in the total number of hippocampal neurons, but the species had a larger hippocampal formation and more hippocampal microglia. It remains to be investigated whether these differences indicate interspecies differences or neural specializations associated with different strategies of orientation and navigation.

  11. Lanostane triterpenoids from Ganoderma curtisii and their NO production inhibitory activities of LPS-induced microglia.

    Science.gov (United States)

    Jiao, Yang; Xie, Ting; Zou, Lu-Hui; Wei, Qian; Qiu, Li; Chen, Li-Xia

    2016-08-01

    Twenty-nine lanostane triterpenoids (1-29) were obtained from the EtOH extract of fruiting bodies of the Ganoderma curtisii. Among them, compound 1 was a new lanostane triterpenoid and compounds 2-5 were isolated from the genus Ganoderma for the first time and their structures were unambiguously identified in this work. The NMR data of the four known lanostane triterpenoids (2-5) were reported for the first time because their structures were all tentatively characterized by interpreting the MS data from the methanol extract of Ganoderma lucidum or from the metabolites in rat bile after oral administration of crude extract of the fruiting bodies of G. lucidum using fragmentation rules. Their anti-inflammatory activities were tested by measuring their inhibitory effects on nitric oxide (NO) production in BV-2 microglia cells activated by lipopolysaccharide. Their IC50 values were in a range from 3.65±0.41 to 28.04±2.81μM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Aquaporin-4 mediates communication between astrocyte and microglia: Implications of neuroinflammation in experimental Parkinson's disease.

    Science.gov (United States)

    Sun, H; Liang, R; Yang, B; Zhou, Y; Liu, M; Fang, F; Ding, J; Fan, Y; Hu, G

    2016-03-11

    Aquaporin-4 (AQP4), a water-selective membrane transport protein, is up-regulated in astrocytes in various inflammatory lesions, including Parkinson disease (PD). However, the exact functional roles of AQP4 in neuroinflammation remain unknown. In the present study, we investigated how AQP4 participates in the neuroinflammation of PD using AQP4 knockout (KO) mice and astrocyte-microglial co-cultures. We found that AQP4 KO mice exhibited increased basal and inducible canonical NF-κB activity, and showed significantly enhanced gliosis (astrocytosis and microgliosis) in chronic MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)/probenecid PD models, companying with the increase in the production of IL-1β and TNF-α in the midbrain. Similarly, AQP4 deficiency augmented the activation of the NF-κB pathway and the production of IL-1β and TNF-α in midbrain astrocyte cultures treated with MPP(+) (1-methyl-4-phenylpyridinium). Furthermore, AQP4 deficiency promoted activation of microglial cells in the co-cultured system. Our data provide the first evidence that AQP4 modulates astrocyte-to-microglia communication in neuroinflammation, although its effect on astrocyte inflammatory activation remains to be explored. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. LXW7 ameliorates focal cerebral ischemia injury and attenuates inflammatory responses in activated microglia in rats

    International Nuclear Information System (INIS)

    Fang, T.; Zhou, D.; Lu, L.; Tong, X.; Wu, J.; Yi, L.

    2016-01-01

    Inflammation plays a pivotal role in ischemic stroke, when activated microglia release excessive pro-inflammatory mediators. The inhibition of integrin αvβ3 improves outcomes in rat focal cerebral ischemia models. However, the mechanisms by which microglia are neuroprotective remain unclear. This study evaluated whether post-ischemic treatment with another integrin αvβ3 inhibitor, the cyclic arginine-glycine-aspartic acid (RGD) peptide-cGRGDdvc (LXW7), alleviates cerebral ischemic injury. The anti-inflammatory effect of LXW7 in activated microglia within rat focal cerebral ischemia models was examined. A total of 108 Sprague-Dawley rats (250–280 g) were subjected to middle cerebral artery occlusion (MCAO). After 2 h, the rats were given an intravenous injection of LXW7 (100 μg/kg) or phosphate-buffered saline (PBS). Neurological scores, infarct volumes, brain water content (BWC) and histology alterations were determined. The expressions of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)], and Iba1-positive activated microglia, within peri-ischemic brain tissue, were assessed with ELISA, western blot and immunofluorescence staining. Infarct volumes and BWC were significantly lower in LXW7-treated rats compared to those in the MCAO + PBS (control) group. The LXW7 treatment lowered the expression of pro-inflammatory cytokines. There was a reduction of Iba1-positive activated microglia, and the TNF-α and IL-1β expressions were attenuated. However, there was no difference in the Zea Longa scores between the ischemia and LXW7 groups. The results suggest that LXW7 protected against focal cerebral ischemia and attenuated inflammation in activated microglia. LXW7 may be neuroprotective during acute MCAO-induced brain damage and microglia-related neurodegenerative diseases

  14. Prostaglandin E2 released from activated microglia enhances astrocyte proliferation in vitro

    International Nuclear Information System (INIS)

    Zhang Dan; Hu Xiaoming; Qian Li; Wilson, Belinda; Lee, Christopher; Flood, Patrick; Langenbach, Robert; Hong, J.-S.

    2009-01-01

    Microglial activation has been implicated in many astrogliosis-related pathological conditions including astroglioma; however, the detailed mechanism is not clear. In this study, we used primary enriched microglia and astrocyte cultures to determine the role of microglial prostaglandin E 2 (PGE 2 ) in the proliferation of astrocytes. The proliferation of astrocytes was measured by BrdU incorporation. The level of PGE 2 was measured by ELISA method. Pharmacological inhibition or genetic ablation of COX-2 in microglia were also applied in this study. We found that proliferation of astrocytes increased following lipopolysaccharide (LPS) treatment in the presence of microglia. Furthermore, increased proliferation of astrocytes was observed in the presence of conditioned media from LPS-treated microglia. The potential involvement of microglial PGE 2 in enhanced astrocyte proliferation was suggested by the findings that PGE 2 production and COX-2 expression in microglia were increased by LPS treatment. In addition, activated microglia-induced increases in astrocyte proliferation were blocked by the PGE 2 antagonist AH6809, COX-2 selective inhibitor DuP-697 or by genetic knockout of microglial COX-2. These findings were further supported by the finding that addition of PGE 2 to the media significantly induced astrocyte proliferation. These results indicate that microglial PGE 2 plays an important role in astrocyte proliferation, identifying PGE 2 as a key neuroinflammatory molecule that triggers the pathological response related to uncontrollable astrocyte proliferation. These findings are important in elucidating the role of activated microglia and PGE 2 in astrocyte proliferation and in suggesting a potential avenue in the use of anti-inflammatory agents for the therapy of astroglioma.

  15. LXW7 ameliorates focal cerebral ischemia injury and attenuates inflammatory responses in activated microglia in rats

    Energy Technology Data Exchange (ETDEWEB)

    Fang, T.; Zhou, D.; Lu, L.; Tong, X.; Wu, J.; Yi, L. [Department of Neurology, Shenzhen Hospital, Peking University, Shenzhen (China)

    2016-08-01

    Inflammation plays a pivotal role in ischemic stroke, when activated microglia release excessive pro-inflammatory mediators. The inhibition of integrin αvβ3 improves outcomes in rat focal cerebral ischemia models. However, the mechanisms by which microglia are neuroprotective remain unclear. This study evaluated whether post-ischemic treatment with another integrin αvβ3 inhibitor, the cyclic arginine-glycine-aspartic acid (RGD) peptide-cGRGDdvc (LXW7), alleviates cerebral ischemic injury. The anti-inflammatory effect of LXW7 in activated microglia within rat focal cerebral ischemia models was examined. A total of 108 Sprague-Dawley rats (250–280 g) were subjected to middle cerebral artery occlusion (MCAO). After 2 h, the rats were given an intravenous injection of LXW7 (100 μg/kg) or phosphate-buffered saline (PBS). Neurological scores, infarct volumes, brain water content (BWC) and histology alterations were determined. The expressions of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)], and Iba1-positive activated microglia, within peri-ischemic brain tissue, were assessed with ELISA, western blot and immunofluorescence staining. Infarct volumes and BWC were significantly lower in LXW7-treated rats compared to those in the MCAO + PBS (control) group. The LXW7 treatment lowered the expression of pro-inflammatory cytokines. There was a reduction of Iba1-positive activated microglia, and the TNF-α and IL-1β expressions were attenuated. However, there was no difference in the Zea Longa scores between the ischemia and LXW7 groups. The results suggest that LXW7 protected against focal cerebral ischemia and attenuated inflammation in activated microglia. LXW7 may be neuroprotective during acute MCAO-induced brain damage and microglia-related neurodegenerative diseases.

  16. α-Iso-cubebene exerts neuroprotective effects in amyloid beta stimulated microglia activation.

    Science.gov (United States)

    Park, Sun Young; Park, Se Jin; Park, Nan Jeong; Joo, Woo Hong; Lee, Sang-Joon; Choi, Young-Whan

    2013-10-25

    Schisandra chinensis is commonly used for food and as a traditional remedy for the treatment of neuronal disorders. However, it is unclear which component of S. chinensis is responsible for its neuropharmacological effects. To answer this question, we isolated α-iso-cubebene, a dibenzocyclooctadiene lignin, from S. chinensis and determined if it has any anti-neuroinflammatory and neuroprotective properties against amyloid β-induced neuroinflammation in microglia. Microglia that are stimulated by amyloid β increased their production of pro-inflammatory cytokines and chemokines, prostaglandin E2 (PGE2), nitric oxide (NO) and reactive oxygen species (ROS) and the enzymatic activity of matrix metalloproteinase 9 (MMP-9). We found this was all inhibited by α-iso-cubebene. Consistent with these results, α-iso-cubebene inhibited the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) and MMP-9 in amyloid β-stimulated microglia. Subsequent mechanistic studies revealed that α-iso-cubebene inhibited the phosphorylation and degradation of IκB-α, the phosphorylation and transactivity of NF-κB, and the phosphorylation of MAPK in amyloid β-stimulated microglia. These results suggest that α-iso-cubebene impairs the amyloid β-induced neuroinflammatory response of microglia by inhibiting the NF-κB and MAPK signaling pathways. Importantly, α-iso-cubebene can provide critical neuroprotection for primary cortical neurons against amyloid β-stimulated microglia-mediated neurotoxicity. To the best of our knowledge, this is the first report showing that α-iso-cubebene can provide neuroprotection against, and influence neuroinflammation triggered by, amyloid β activation of microglia. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Curcumin protects microglia and primary rat cortical neurons against HIV-1 gp120-mediated inflammation and apoptosis.

    Directory of Open Access Journals (Sweden)

    Luyan Guo

    Full Text Available Curcumin is a molecule found in turmeric root that has anti-inflammatory, antioxidant, and anti-tumor properties and has been widely used as both an herbal drug and a food additive to treat or prevent neurodegenerative diseases. To explore whether curcumin is able to ameliorate HIV-1-associated neurotoxicity, we treated a murine microglial cell line (N9 and primary rat cortical neurons with curcumin in the presence or absence of neurotoxic HIV-1 gp120 (V3 loop protein. We found that HIV-1 gp120 profoundly induced N9 cells to produce reactive oxygen species (ROS, tumor necrosis factor-α (TNF-α and monocyte chemoattractant protein-1 (MCP-1. HIV-1 gp120 also induced apoptosis of primary rat cortical neurons. Curcumin exerted a powerful inhibitory effect against HIV-1 gp120-induced neuronal damage, reducing the production of ROS, TNF-α and MCP-1 by N9 cells and inhibiting apoptosis of primary rat cortical neurons. Curcumin may exert its biological activities through inhibition of the delayed rectification and transient outward potassium (K(+ current, as curcumin effectively reduced HIV-1 gp120-mediated elevation of the delayed rectification and transient outward K(+ channel current in neurons. We conclude that HIV-1 gp120 increases ROS, TNF-α and MCP-1 production in microglia, and induces cortical neuron apoptosis by affecting the delayed rectification and transient outward K(+ channel current. Curcumin reduces production of ROS and inflammatory mediators in HIV-1-gp120-stimulated microglia, and protects cortical neurons against HIV-1-mediated apoptosis, most likely through inhibition of HIV-1 gp120-induced elevation of the delayed rectification and transient outward K(+ current.

  18. 6-Mercaptopurine attenuates tumor necrosis factor-α production in microglia through Nur77-mediated transrepression and PI3K/Akt/mTOR signaling-mediated translational regulation.

    Science.gov (United States)

    Huang, Hsin-Yi; Chang, Hui-Fen; Tsai, Ming-Jen; Chen, Jhih-Si; Wang, Mei-Jen

    2016-04-13

    The pathogenesis of several neurodegenerative diseases often involves the microglial activation and associated inflammatory processes. Activated microglia release pro-inflammatory factors that may be neurotoxic. 6-Mercaptopurine (6-MP) is a well-established immunosuppressive drug. Common understanding of their immunosuppressive properties is largely limited to peripheral immune cells. However, the effect of 6-MP in the central nervous system, especially in microglia in the context of neuroinflammation is, as yet, unclear. Tumor necrosis factor-α (TNF-α) is a key cytokine of the immune system that initiates and promotes neuroinflammation. The present study aimed to investigate the effect of 6-MP on TNF-α production by microglia to discern the molecular mechanisms of this modulation. Lipopolysaccharide (LPS) was used to induce an inflammatory response in cultured primary microglia or murine BV-2 microglial cells. Released TNF-α was measured by enzyme-linked immunosorbent assay (ELISA). Gene expression was determined by real-time reverse transcription polymerase chain reaction (RT-PCR). Signaling molecules were analyzed by western blotting, and activation of NF-κB was measured by ELISA-based DNA binding analysis and luciferase reporter assay. Chromatin immunoprecipitation (ChIP) analysis was performed to examine NF-κB p65 and coactivator p300 enrichments and histone modifications at the endogenous TNF-α promoter. Treatment of LPS-activated microglia with 6-MP significantly attenuated TNF-α production. In 6-MP pretreated microglia, LPS-induced MAPK signaling, IκB-α degradation, NF-κB p65 nuclear translocation, and in vitro p65 DNA binding activity were not impaired. However, 6-MP suppressed transactivation activity of NF-κB and TNF-α promoter by inhibiting phosphorylation and acetylation of p65 on Ser276 and Lys310, respectively. ChIP analyses revealed that 6-MP dampened LPS-induced histone H3 acetylation of chromatin surrounding the TNF-α promoter

  19. Maximal COX-2 and ppRb expression in neurons occurs during early Braak stages prior to the maximal activation of astrocytes and microglia in Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Arendt Thomas

    2005-11-01

    Full Text Available Abstract Neuronal expression of cyclooxygenase-2 (COX-2 and cell cycle proteins is suggested to contribute to neurodegeneration during Alzheimer's disease (AD. The stimulus that induces COX-2 and cell cycle protein expression in AD is still elusive. Activated glia cells are shown to secrete substances that can induce expression of COX-2 and cell cycle proteins in vitro. Using post mortem brain tissue we have investigated whether activation of microglia and astrocytes in AD brain can be correlated with the expression of COX-2 and phosphorylated retinoblastoma protein (ppRb. The highest levels of neuronal COX-2 and ppRb immunoreactivity are observed in the first stages of AD pathology (Braak 0–II, Braak A. No significant difference in COX-2 or ppRb neuronal immunoreactivity is observed between Braak stage 0 and later Braak stages for neurofibrillary changes or amyloid plaques. The mean number of COX-2 or ppRb immunoreactive neurons is significantly decreased in Braak stage C compared to Braak stage A for amyloid deposits. Immunoreactivity for glial markers KP1, CR3/43 and GFAP appears in the later Braak stages and is significantly increased in Braak stage V-VI compared to Braak stage 0 for neurofibrillary changes. In addition, a significant negative correlation is observed between the presence of KP1, CR3/43 and GFAP immunoreactivity and the presence of neuronal immunoreactivity for COX-2 and ppRb. These data show that maximal COX-2 and ppRb immunoreactivity in neurons occurs during early Braak stages prior to the maximal activation of astrocytes and microglia. In contrast to in vitro studies, post mortem data do not support a causal relation between the activation of microglia and astrocytes and the expression of neuronal COX-2 and ppRb in the pathological cascade of AD.

  20. Exploring the role of microglia in mood disorders associated with experimental multiple sclerosis

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    Antonietta eGentile

    2015-06-01

    Full Text Available Microglia is increasingly recognized to play a crucial role in the pathogenesis of psychiatric diseases. In particular, microglia may be the cellular link between inflammation and behavioural alterations: by releasing a number of soluble factors, among which pro-inflammatory cytokines, they can regulate synaptic activity, thereby leading to perturbation of behaviour.In multiple sclerosis (MS, the most common neuroinflammatory disorder affecting young adults, microglia activation and dysfunction may account for mood symptoms, like depression and anxiety, that are often diagnosed in patients even in the absence of motor disability. Behavioural studies in experimental autoimmune encephalomyelitis (EAE, the animal model of MS, have shown that emotional changes occur early in the disease and in correlation to inflammatory mediator and neurotransmitter level alterations. However, such studies lack a full and comprehensive analysis of the role played by microglia in EAE-behavioural syndrome. We review the experimental studies addressing behavioural symptoms in EAE, and propose the study of neuron-glia interaction as a powerful but still poorly explored tool to investigate the burden of microglia in mood alterations associated to MS.

  1. Astroglia-Microglia Cross Talk during Neurodegeneration in the Rat Hippocampus

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    Montserrat Batlle

    2015-01-01

    Full Text Available Brain injury triggers a progressive inflammatory response supported by a dynamic astroglia-microglia interplay. We investigated the progressive chronic features of the astroglia-microglia cross talk in the perspective of neuronal effects in a rat model of hippocampal excitotoxic injury. N-Methyl-D-aspartate (NMDA injection triggered a process characterized within 38 days by atrophy, neuronal loss, and fast astroglia-mediated S100B increase. Microglia reaction varied with the lesion progression. It presented a peak of tumor necrosis factor-α (TNF-α secretion at one day after the lesion, and a transient YM1 secretion within the first three days. Microglial glucocorticoid receptor expression increased up to day 5, before returning progressively to sham values. To further investigate the astroglia role in the microglia reaction, we performed concomitant transient astroglia ablation with L-α-aminoadipate and NMDA-induced lesion. We observed a striking maintenance of neuronal death associated with enhanced microglial reaction and proliferation, increased YM1 concentration, and decreased TNF-α secretion and glucocorticoid receptor expression. S100B reactivity only increased after astroglia recovery. Our results argue for an initial neuroprotective microglial reaction, with a direct astroglial control of the microglial cytotoxic response. We propose the recovery of the astroglia-microglia cross talk as a tissue priority conducted to ensure a proper cellular coordination that retails brain damage.

  2. Vascular consequences of passive Aβ immunization for Alzheimer's disease. Is avoidance of "malactivation" of microglia enough?

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    Barger Steven W

    2005-01-01

    Full Text Available Abstract The role of inflammation in Alzheimer's disease (AD has been controversial since its first consideration. As with most instances of neuroinflammation, the possibility must be considered that activation of glia and cytokine networks in AD arises merely as a reaction to neurodegeneration. Active, healthy neurons produce signals that suppress inflammatory events, and dying neurons activate phagocytic responses in microglia at the very least. But simultaneous with the arrival of a more complex view of microglia, evidence that inflammation plays a causal or exacerbating role in AD etiology has been boosted by genetic, physiological, and epidemiological studies. In the end, it may be that the semantics of "inflammation" and glial "activation" must be regarded as too simplistic for the advancement of our understanding in this regard. It is clear that elaboration of the entire repertoire of activated microglia – a phenomenon that may be termed "malactivation" – must be prevented for healthy brain structure and function. Nevertheless, recent studies have suggested that phagocytosis of Aβ by microglia plays an important role in clearance of amyloid plaques, a process boosted by immunization paradigms. To the extent that this clearance might produce clinical improvements (still an open question, this relationship thus obligates a more nuanced consideration of the factors that indicate and control the various activities of microglia and other components of neuroinflammation.

  3. Astroglia-Microglia Cross Talk during Neurodegeneration in the Rat Hippocampus

    Science.gov (United States)

    Batlle, Montserrat; Ferri, Lorenzo; Andrade, Carmen; Ortega, Francisco-Javier; Vidal-Taboada, Jose M.; Pugliese, Marco; Mahy, Nicole; Rodríguez, Manuel J.

    2015-01-01

    Brain injury triggers a progressive inflammatory response supported by a dynamic astroglia-microglia interplay. We investigated the progressive chronic features of the astroglia-microglia cross talk in the perspective of neuronal effects in a rat model of hippocampal excitotoxic injury. N-Methyl-D-aspartate (NMDA) injection triggered a process characterized within 38 days by atrophy, neuronal loss, and fast astroglia-mediated S100B increase. Microglia reaction varied with the lesion progression. It presented a peak of tumor necrosis factor-α (TNF-α) secretion at one day after the lesion, and a transient YM1 secretion within the first three days. Microglial glucocorticoid receptor expression increased up to day 5, before returning progressively to sham values. To further investigate the astroglia role in the microglia reaction, we performed concomitant transient astroglia ablation with L-α-aminoadipate and NMDA-induced lesion. We observed a striking maintenance of neuronal death associated with enhanced microglial reaction and proliferation, increased YM1 concentration, and decreased TNF-α secretion and glucocorticoid receptor expression. S100B reactivity only increased after astroglia recovery. Our results argue for an initial neuroprotective microglial reaction, with a direct astroglial control of the microglial cytotoxic response. We propose the recovery of the astroglia-microglia cross talk as a tissue priority conducted to ensure a proper cellular coordination that retails brain damage. PMID:25977914

  4. Amyloid-β(1–42) Protofibrils Formed in Modified Artificial Cerebrospinal Fluid Bind and Activate Microglia

    Science.gov (United States)

    Paranjape, Geeta S.; Terrill, Shana E.; Gouwens, Lisa K.; Ruck, Benjamin M.; Nichols, Michael R.

    2012-01-01

    Soluble aggregated forms of amyloid-β protein (Aβ) have garnered significant attention recently for their role in Alzheimer’s disease (AD). Protofibrils are a subset of these soluble species and are considered intermediates in the aggregation pathway to mature Aβ fibrils. Biological studies have demonstrated that protofibrils exhibit both toxic and inflammatory activities. It is important in these in vitro studies to prepare protofibrils using solution conditions that are appropriate for cellular studies as well as conducive to biophysical characterization of protofibrils. Here we describe the preparation and characterization of Aβ(1–42) protofibrils in modified artificial cerebrospinal fluid (aCSF) and demonstrate their prominent binding and activation of microglial cells. A simple phosphate/bicarbonate buffer system was prepared that maintained the ionic strength and cell compatibility of F-12 medium but did not contain numerous supplements that interfere with spectroscopic analyses of Aβ protofibrils. Reconstitution of Aβ(1–42) in aCSF and isolation with size exclusion chromatography (SEC) revealed curvilinear β-sheet protofibrils <100 nm in length and hydrodynamic radii of 21 nm. Protofibril concentration determination by BCA assay, which was not possible in F-12 medium, was more accurately measured in aCSF. Protofibrils formed and isolated in aCSF, but not monomers, markedly stimulated TNFα production in BV-2 and primary microglia and bound in significant amounts to microglial membranes. This report demonstrates the suitability of a modified aCSF system for preparing SEC-isolated Aβ(1–42) protofibrils and underscores the unique ability of protofibrils to functionally interact with microglia. PMID:23242692

  5. Kynurenine pathway metabolic balance influences microglia activity: Targeting kynurenine monooxygenase to dampen neuroinflammation.

    Science.gov (United States)

    Garrison, Allison M; Parrott, Jennifer M; Tuñon, Arnulfo; Delgado, Jennifer; Redus, Laney; O'Connor, Jason C

    2018-08-01

    Chronic stress or inflammation increases tryptophan metabolism along the kynurenine pathway (KP), and the generation of neuroactive kynurenine metabolites contributes to subsequent depressive-like behaviors. Microglia regulate KP balance by preferentially producing oxidative metabolites, including quinolinic acid. Research has focused on the interplay between cytokines and HPA axis-derived corticosteroids in regulating microglial activity and effects of KP metabolites directly on neurons; however, the potential role that KP metabolites have directly on microglial activity is unknown. Here, murine microglia were stimulated with lipopolysaccharide(LPS). After 6 h, mRNA expression of interleukin(IL)-1β, IL-6, tumor necrosis factor(TNF)-α and inducible nitric oxide synthase(iNOS) was dose-dependently increased along with the rate-limiting enzymes for oxidative KP metabolism, indoleamine-2,3-dioxygenase(IDO)-1 and kynurenine 3-monooxygenase(KMO). By 24 h post-LPS, kynurenine and quinolinic acid in the media was elevated. Inhibiting KMO with Ro 61-8048 during LPS challenge attenuated extracellular nitrite accumulation and expression of KMO and TNF-α in response to LPS. Similarly, primary microglia isolated from KMO -/- mice exhibited a significantly reduced pro-inflammatory response to LPS compared to WT controls. To determine whether the substrate (kynurenine) or end product (quinolinic acid) of KMO-dependent metabolism modulates the LPS response, microglia were treated with increasing concentrations of L-kynurenine or quinolinic acid in combination with LPS or saline. Interestingly, quinolinic acid did not impact the microglial LPS response. However, L-kynurenine had dose-dependent inhibitory effect on the LPS response. These data are the first to show an anti-inflammatory effect of KMO inhibition on microglia during immune challenge and suggest that KP metabolic balance may play a direct role in regulating microglia activity. Published by Elsevier Ltd.

  6. Vesicle-mediated transport and release of CCL21 in endangered neurons : A possible explanation for microglia activation remote from a primary lesion

    NARCIS (Netherlands)

    de Jong, EK; Dijkstra, IM; Hensens, M; Brouwer, N; van Amerongen, M; Liem, RSB; Boddeke, HWGM; Biber, K

    2005-01-01

    Whenever neurons in the CNS are injured, microglia become activated. In addition to local activation, microglia remote from the primary lesion site are stimulated. Because this so-called secondary activation of microglia is instrumental for long-term changes after neuronal injury, it is important to

  7. RAGE-Specific Inhibitor FPS-ZM1 Attenuates AGEs-Induced Neuroinflammation and Oxidative Stress in Rat Primary Microglia.

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    Shen, Chao; Ma, Yingjuan; Zeng, Ziling; Yin, Qingqing; Hong, Yan; Hou, Xunyao; Liu, Xueping

    2017-10-01

    Advanced glycation end products (AGEs) enhance microglial activation and intensify the inflammatory response and oxidative stress in the brain. This process may occur due to direct cytotoxicity or interacting with AGEs receptors (RAGE), which are expressed on the surface of microglia. FPS-ZM1 is a high-affinity but nontoxic RAGE-specific inhibitor that has been recently shown to attenuate the Aβ-induced inflammatory response by blocking the ligation of Aβ to RAGE. In this study, we further investigated the effect of FPS-ZM1 on the AGEs/RAGE interaction and downstream elevation of neuroinflammation and oxidative stress in primary microglia cells. The results suggested that FPS-ZM1 significantly suppressed AGEs-induced RAGE overexpression, RAGE-dependent microglial activation, nuclear translocation of nuclear factor kappaB p65 (NF-κB p65), and the expression of downstream inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) and inducible nitric oxide synthase (iNOS)/nitric oxide (NO). Furthermore, FPS-ZM1 attenuated AGEs-stimulated NADPH oxidase (NOX) activation and reactive oxygen species (ROS) expression. Finally, FPS-ZM1 elevated the levels of transcription factors nuclear-factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1), as well as decreased antioxidant capacity and increased production of oxidative species. Our results suggest that FPS-ZM1 may be neuroprotective through attenuating microglial activation, oxidative stress and inflammation by blocking RAGE.

  8. Differentially Severe Cognitive Effects of Compromised Cerebral Blood Flow in Aged Mice: Association with Myelin Degradation and Microglia Activation

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    Gilly Wolf

    2017-06-01

    Full Text Available Bilateral common carotid artery stenosis (BCAS models the effects of compromised cerebral blood flow on brain structure and function in mice. We compared the effects of BCAS in aged (21 month and young adult (3 month female mice, anticipating a differentially more severe effect in the older mice. Four weeks after surgery there was a significant age by time by treatment interaction on the radial-arm water maze (RAWM; p = 0.014: on the first day of the test, latencies of old mice were longer compared to the latencies of young adult mice, independent of BCAS. However, on the second day of the test, latencies of old BCAS mice were significantly longer than old control mice (p = 0.049, while latencies of old controls were similar to those of the young adult mice, indicating more severe impairment of hippocampal dependent learning and working memory by BCAS in the older mice. Fluorescence staining of myelin basic protein (MBP showed that old age and BCAS both induced a significant decrease in fluorescence intensity. Evaluation of the number oligodendrocyte precursor cells demonstrated augmented myelin replacement in old BCAS mice (p < 0.05 compared with young adult BCAS and old control mice. While microglia morphology was assessed as normal in young adult control and young adult BCAS mice, microglia of old BCAS mice exhibited striking activation in the area of degraded myelin compared to young adult BCAS (p < 0.01 and old control mice (p < 0.05. These findings show a differentially more severe effect of cerebral hypoperfusion on cognitive function, myelin integrity and inflammatory processes in aged mice. Hypoperfusion may exacerbate degradation initiated by aging, which may induce more severe neuronal and cognitive phenotypes.

  9. Inhibitory effects of diallyl disulfide on the production of inflammatory mediators and cytokines in lipopolysaccharide-activated BV2 microglia

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hye Young [Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-714 (Korea, Republic of); Department of Pharmacy, Pusan National University, Busan 609-735 (Korea, Republic of); Kim, Nam Deuk [Department of Pharmacy, Pusan National University, Busan 609-735 (Korea, Republic of); Kim, Gi-Young [Department of Marine Life Sciences, Jeju National University, Jeju 690-756 (Korea, Republic of); Hwang, Hye Jin [Anti-Aging Research Center and Blue-Bio Industry RIC, Dongeui University, Busan 614-714 (Korea, Republic of); Department of Food and Nutrition, College of Human Ecology, Dongeui University, Busan 614-714 (Korea, Republic of); Kim, Byung-Woo [Anti-Aging Research Center and Blue-Bio Industry RIC, Dongeui University, Busan 614-714 (Korea, Republic of); Department of Life Science and Biotechnology, College of Natural Science, Dongeui University, Busan 614-714 (Korea, Republic of); Department of Biomaterial Control, Graduate School, Dongeui University, Busan 614-714 (Korea, Republic of); Kim, Wun Jae [Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Choi, Yung Hyun, E-mail: choiyh@deu.ac.kr [Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-714 (Korea, Republic of); Anti-Aging Research Center and Blue-Bio Industry RIC, Dongeui University, Busan 614-714 (Korea, Republic of); Department of Biomaterial Control, Graduate School, Dongeui University, Busan 614-714 (Korea, Republic of)

    2012-07-15

    Diallyl disulfide (DADS), a main organosulfur component responsible for the diverse biological effects of garlic, displays a wide variety of internal biological activities. However, the cellular and molecular mechanisms underlying DADS' anti-inflammatory activity remain poorly understood. In this study, therefore, the anti-inflammatory effects of DADS were studied to investigate its potential therapeutic effects in lipopolysaccharide (LPS)-stimulated BV2 microglia. We found that pretreatment with DADS prior to treatment with LPS significantly inhibited excessive production of nitric oxide (NO) and prostaglandin E{sub 2} (PGE{sub 2}) in a dose-dependent manner. The inhibition was associated with down-regulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. DADS also attenuated the production of pro-inflammatory cytokines and chemokines, including interleukin-1β (IL-1β), tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein-1 (MCP-1) by suppressing the expression of mRNAs for these proteins. The mechanism underlying this protective effect might be related to the inhibition of nuclear factor-kappaB, Akt and mitogen-activated protein kinase signaling pathway activation in LPS-stimulated microglial cells. These findings indicated that DADS is potentially a novel therapeutic candidate for the treatment of various neurodegenerative diseases. -- Highlights: ► DADS attenuates production of NO and PGE2 in LPS-activated BV2 microglia. ► DADS downregulates levels of iNOS and COX-2. ► DADS inhibits production and expression of inflammatory cytokines and chemokine. ► DADS exhibits these effects by suppression of NF-κB, PI3K/Akt and MAPKs pathways.

  10. Extended magnetic resonance imaging studies on the effect of classically activated microglia transplantation on white matter regeneration following spinal cord focal injury in adult rats.

    Science.gov (United States)

    Marcol, Wiesław; Ślusarczyk, Wojciech; Larysz-Brysz, Magdalena; Łabuzek, Krzysztof; Kapustka, Bartosz; Staszkiewicz, Rafał; Rosicka, Paulina; Kalita, Katarzyna; Węglarz, Władysław; Lewin-Kowalik, Joanna

    2017-11-01

    Spinal cord injuries are still a serious problem for regenerative medicine. Previous research has demonstrated that activated microglia accumulate in spinal lesions, influencing the injured tissues in various ways. Therefore, transplantation of activated microglia may have a beneficial role in the regeneration of the nervous system. The present study examined the influence of transplanted activated microglial cells in adult rats with injured spinal cords. Rats were randomly divided into an experimental (M) and control (C) group, and were subjected to non-laminectomy focal injury of spinal cord white matter by means of a high-pressured air stream. In group M, activated cultured microglial cells were injected twice into the site of injury. Functional outcome and morphological features of regeneration were analyzed during a 12-week follow-up. The lesions were characterized by means of magnetic resonance imaging (MRI). Neurons in the brain stem and motor cortex were labeled with FluoroGold (FG). A total of 12 weeks after surgery, spinal cords and brains were collected and subjected to histopathological and immunohistochemical examinations. Lesion sizes in the spinal cord were measured and the number of FG-positive neurons was counted. Rats in group M demonstrated significant improvement of locomotor performance when compared with group C (Pspinal cord in the group M following microglia treatment, as compared with group C. The water diffusion perpendicular to the spinal cord in group M was closer to the reference values for a healthy spinal cord than it was in group C. The sizes of lesions were also significantly smaller in group M than in the group C (Pspinal cord gives some positive effects for the regeneration of the white matter.

  11. Transformation of Astrocytes to a Neuroprotective Phenotype by Microglia via P2Y1 Receptor Downregulation

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    Youichi Shinozaki

    2017-05-01

    Full Text Available Microglia and astrocytes become reactive following traumatic brain injury (TBI. However, the coordination of this reactivity and its relation to pathophysiology are unclear. Here, we show that microglia transform astrocytes into a neuroprotective phenotype via downregulation of the P2Y1 purinergic receptor. TBI initially caused microglial activation in the injury core, followed by reactive astrogliosis in the peri-injured region and formation of a neuroprotective astrocyte scar. Equivalent changes to astrocytes were observed in vitro after injury. This change in astrocyte phenotype resulted from P2Y1 receptor downregulation, mediated by microglia-derived cytokines. In mice, astrocyte-specific P2Y1 receptor overexpression (Astro-P2Y1OE counteracted scar formation, while astrocyte-specific P2Y1 receptor knockdown (Astro-P2Y1KD facilitated scar formation, suggesting critical roles of P2Y1 receptors in the transformation. Astro-P2Y1OE and Astro-P2Y1KD mice showed increased and reduced neuronal damage, respectively. Altogether, our findings indicate that microglia-astrocyte interaction, involving a purinergic signal, is essential for the formation of neuroprotective astrocytes.

  12. Microglia PACAP and glutamate: Friends or foes in seizure-induced autonomic dysfunction and SUDEP?

    Science.gov (United States)

    Bhandare, Amol M; Kapoor, Komal; Farnham, Melissa M J; Pilowsky, Paul M

    2016-06-01

    Seizure-induced cardiorespiratory autonomic dysfunction is a major cause of sudden unexpected death in epilepsy (SUDEP), and the underlying mechanism is unclear. Seizures lead to increased synthesis, and release of glutamate, pituitary adenylate cyclase activating polypeptide (PACAP), and other neurotransmitters, and cause extensive activation of microglia at multiple regions in the brain including central autonomic cardiorespiratory brainstem nuclei. Glutamate contributes to neurodegeneration, and inflammation in epilepsy. PACAP has neuroprotective, and anti-inflammatory properties, whereas microglia are key players in inflammatory responses in CNS. Seizure-induced increase in PACAP is neuroprotective. PACAP produces neuroprotective effects acting on microglial PAC1 and VPAC1 receptors. Microglia also express glutamate transporters, and their expression can be increased by PACAP in response to harmful or stressful situations such as seizures. Here we discuss the mechanism of autonomic cardiorespiratory dysfunction in seizure, and the role of PACAP, glutamate and microglia in regulating cardiorespiratory brainstem neurons in their physiological state that could provide future therapeutic options for SUDEP. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Critical Data-Based Re-Evaluation of Minocycline as a Putative Specific Microglia Inhibitor

    NARCIS (Netherlands)

    Moller, Thomas; Bard, Frederique; Bhattacharya, Anindya; Biber, Knut; Campbell, Brian; Dale, Elena; Eder, Claudia; Gan, Li; Garden, Gwenn A.; Hughes, Zoe A.; Pearse, Damien D.; Staal, Roland G. W.; Sayed, Faten A.; Wes, Paul D.; Boddeke, Hendrikus W. G. M.

    2016-01-01

    Minocycline, a second generation broad-spectrum antibiotic, has been frequently postulated to be a "microglia inhibitor." A considerable number of publications have used minocycline as a tool and concluded, after achieving a pharmacological effect, that the effect must be due to "inhibition" of

  14. Microglia in diffuse plaques in hereditary cerebral hemorrhage with amyloidosis (Dutch). An immunohistochemical study

    NARCIS (Netherlands)

    Maat-Schieman, M. L.; Rozemuller, A. J.; van Duinen, S. G.; Haan, J.; Eikelenboom, P.; Roos, R. A.

    1994-01-01

    In hereditary cerebral hemorrhage with amyloidosis (Dutch) (HCHWA-D) beta/A4 amyloid deposition is found in meningocortical blood vessels and in diffuse plaques in the cerebral cortex. Diffuse plaques putatively represent early stages in the formation of senile plaques. Microglia are intimately

  15. Evidence of Tau Hyperphosphorylation and Dystrophic Microglia in the Common Marmoset.

    Science.gov (United States)

    Rodriguez-Callejas, Juan D; Fuchs, Eberhard; Perez-Cruz, Claudia

    2016-01-01

    Common marmosets ( Callithrix jacchus ) have recently gained popularity in biomedical research as models of aging research. Basically, they confer advantages from other non-human primates due to their shorter lifespan with onset of appearance of aging at 8 years. Old marmosets present some markers linked to neurodegeneration in the brain such as amyloid beta (Aβ) 1-42 and Aβ 1-40 . However, there are no studies exploring other cellular markers associated with neurodegenerative diseases in this non-human primate. Using immunohistochemistry, we analyzed brains of male adolescent, adult, old, and aged marmosets. We observed accumulation of Aβ 1-40 and Aβ 1-42 in the cortex of aged subjects. Tau hyperphosphorylation was already detected in the brain of adolescent animals and increased with aging in a more fibrillary form. Microglia activation was also observed in the aging process, while a dystrophic phenotype accumulates in aged subjects. Interestingly, dystrophic microglia contained hyperphosphorylated tau, but active microglia did not. These results support previous findings regarding microglia dysfunctionality in aging and neurodegenerative diseases as Alzheimer's disease. Further studies should explore the functional consequences of these findings to position this non-human primate as animal model of aging and neurodegeneration.

  16. Microglia protect neurons against ischemia by synthesis of tumor necrosis factor

    DEFF Research Database (Denmark)

    Lambertsen, Kate Lykke; Clausen, Bettina Hjelm; Babcock, Alicia

    2009-01-01

    Microglia and infiltrating leukocytes are considered major producers of tumor necrosis factor (TNF), which is a crucial player in cerebral ischemia and brain inflammation. We have identified a neuroprotective role for microglial-derived TNF in cerebral ischemia in mice. We show that cortical...

  17. Myelin down-regulates myelin phagocytosis by microglia and macrophages through interactions between CD47 on myelin and SIRPα (signal regulatory protein-α on phagocytes

    Directory of Open Access Journals (Sweden)

    Reichert Fanny

    2011-03-01

    Full Text Available Abstract Background Traumatic injury to axons produces breakdown of axons and myelin at the site of the lesion and then further distal to this where Wallerian degeneration develops. The rapid removal of degenerated myelin by phagocytosis is advantageous for repair since molecules in myelin impede regeneration of severed axons. Thus, revealing mechanisms that regulate myelin phagocytosis by macrophages and microglia is important. We hypothesize that myelin regulates its own phagocytosis by simultaneous activation and down-regulation of microglial and macrophage responses. Activation follows myelin binding to receptors that mediate its phagocytosis (e.g. complement receptor-3, which has been previously studied. Down-regulation, which we test here, follows binding of myelin CD47 to the immune inhibitory receptor SIRPα (signal regulatory protein-α on macrophages and microglia. Methods CD47 and SIRPα expression was studied by confocal immunofluorescence microscopy, and myelin phagocytosis by ELISA. Results We first document that myelin, oligodendrocytes and Schwann cells express CD47 without SIRPα and further confirm that microglia and macrophages express both CD47 and SIRPα. Thus, CD47 on myelin can bind to and subsequently activate SIRPα on phagocytes, a prerequisite for CD47/SIRPα-dependent down-regulation of CD47+/+ myelin phagocytosis by itself. We then demonstrate that phagocytosis of CD47+/+ myelin is augmented when binding between myelin CD47 and SIRPα on phagocytes is blocked by mAbs against CD47 and SIRPα, indicating that down-regulation of phagocytosis indeed depends on CD47-SIRPα binding. Further, phagocytosis in serum-free medium of CD47+/+ myelin is augmented after knocking down SIRPα levels (SIRPα-KD in phagocytes by lentiviral infection with SIRPα-shRNA, whereas phagocytosis of myelin that lacks CD47 (CD47-/- is not. Thus, myelin CD47 produces SIRPα-dependent down-regulation of CD47+/+ myelin phagocytosis in phagocytes

  18. Histamine Regulates the Inflammatory Profile of SOD1-G93A Microglia and the Histaminergic System Is Dysregulated in Amyotrophic Lateral Sclerosis

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    Savina Apolloni

    2017-11-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a late-onset motor neuron disease where activated glia release pro-inflammatory cytokines that trigger a vicious cycle of neurodegeneration in the absence of resolution of inflammation. Given the well-established role of histamine as a neuron-to-glia alarm signal implicated in brain disorders, the aim of this study was to investigate the expression and regulation of the histaminergic pathway in microglial activation in ALS mouse model and in humans. By examining the contribution of the histaminergic system to ALS, we found that particularly via H1 and H4 receptors, histamine promoted an anti-inflammatory profile in microglia from SOD1-G93A mice by modulating their activation state. A decrease in NF-κB and NADPH oxidase 2 with an increase in arginase 1 and P2Y12 receptor was induced by histamine only in the ALS inflammatory environment, but not in the healthy microglia, together with an increase in IL-6, IL-10, CD163, and CD206 phenotypic markers in SOD1-G93A cells. Moreover, histaminergic H1, H2, H3, and H4 receptors, and histamine metabolizing enzymes histidine decarboxylase, histamine N-methyltransferase, and diamine oxidase were found deregulated in spinal cord, cortex, and hypothalamus of SOD1-G93A mice during disease progression. Finally, by performing a meta-analysis study, we found a modulated expression of histamine-related genes in cortex and spinal cord from sporadic ALS patients. Our findings disclose that histamine acts as anti-inflammatory agent in ALS microglia and suggest a dysregulation of the histaminergic signaling in ALS.

  19. Histone Acetylation in Microglia Contributes to Exercise-Induced Hypoalgesia in Neuropathic Pain Model Mice.

    Science.gov (United States)

    Kami, Katsuya; Taguchi, Satoru; Tajima, Fumihiro; Senba, Emiko

    2016-05-01

    Physical exercise can attenuate neuropathic pain (NPP), but the exact mechanism underlying exercise-induced hypoalgesia (EIH) remains unclear. Recent studies have shown that histone hyperacetylation via pharmacological inhibition of histone deacetylases in the spinal cord attenuates NPP, and that histone acetylation may lead to the production of analgesic factors including interleukin 10. We intended to clarify whether histone acetylation in microglia in the spinal dorsal horn contributes to EIH in NPP model mice. C57BL/6J mice underwent partial sciatic nerve ligation (PSL) and PSL- and sham-runner mice ran on a treadmill at a speed of 7 m/min for 60 min/d, 5 days per week, from 2 days after the surgery. PSL-sedentary mice developed mechanical allodynia and heat hyperalgesia, but such behaviors were significantly attenuated in PSL-runner mice. In immunofluorescence analysis, PSL surgery markedly increased the number of histone deacetylase 1-positive/CD11b-positive microglia in the ipsilateral superficial dorsal horn, and they were significantly decreased by treadmill-running. Moreover, the number of microglia with nuclear expression of acetylated H3K9 in the ipsilateral superficial dorsal horn was maintained at low levels in PSL-sedentary mice, but running exercise significantly increased them. Therefore, we conclude that the epigenetic modification that causes hyperacetylation of H3K9 in activated microglia may play a role in producing EIH. This article presents the importance of epigenetic modification in microglia in producing EIH. The current research is not only helpful for developing novel nonpharmacological therapy for NPP, but will also enhance our understanding of the mechanisms and availability of exercise in our daily life. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  20. Microglia are involve in pain related behaviors during the acute and chronic phase of arthritis inflammation

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    Behzad Nasseri

    2016-08-01

    Full Text Available AbstractBackground: Pain is one of the main protests of inflammatory diseases, hence, understanding the mechanisms which involved in the induction and persistence of pain is essential. Microglia is a contributing factor in the onset and maintenance of inflammation. Increased microglial   activation increases the level of central pro-inflammatory cytokines and the development of central sensitization following inflammation. The aim of this study was evaluate the relation of spinal microglia activity with pain related behaviors during Complete Freund’s adjuvant (CFA-induced inflammation.Materials and Methods: Inflammation caused by subcutaneous injection of Complete Freund’s adjuvant (CFA in a single dose to the animals right hind paw. The edema and hyperalgesia caused by inflammation, respectively are measured by Plethysmometer and Radiant Heat, on days 0,7,14 and 21. Spinal Iba-1 protein expression was detected by Western blotting. Minocycline hydrochloride (Sigma, U.S.A was administered i.p. at a dose of 40mg/kg daily.Results: Our study findings indicated that CFA injection to right hindpaw of rats increased paw volume and hyperalgesia significantly during different stages of study, while Minocycline treatment significantly reduced paw volume and hyperalgesia. CFA injection into the right hindpaw of the rat increases the expression of molecules Ionized calcium binding adaptor molecule -1 (Iba-1 on different days of study, while Minocycline administration reduced spinal Iba-1 expression significantly compared to the CFA group.Conclusion: The results of this study indicated the significant roles of microglia activation in deterioration of pain related behaviors during different stages of CFA-induced inflammation. The steady injection of Minocycline (as a microglia inhibitor could reduce the inflammatory symptoms.Keywords: Inflammation, pain, microglia, minocycline

  1. The Plant-Derived Chalcone 2,2′,5′-Trihydroxychalcone Provides Neuroprotection against Toll-Like Receptor 4 Triggered Inflammation in Microglia

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    Manasi Jiwrajka

    2016-01-01

    Full Text Available Chalcones are plant metabolites with potential for therapeutic exploitation as antioxidant, anti-inflammatory, and antiproliferative agents. Here we explored the neuroprotective effects of 2,2′,5′-trihydroxychalcone (225THC, a potent antioxidant with radical-scavenging properties. 225THC was found to be a potent inhibitor of apoptosis in stimulated primary rat neuronal cultures. This was likely mediated by an anti-inflammatory effect on microglial cells since 225THC inhibited LPS-stimulated TNF-α and IL-6 secretion from primary rat microglia and modulated the cytokine/chemokine profile of BV2 microglial cells. Additionally, 225THC inhibited LPS-evoked inducible nitric oxide synthase expression but did not influence endogenous superoxide generation. Microglial flow cytometric analyses indicated the 225THC treatment induced a shift from an M1-like phenotype to a more downregulated microglial profile. Taken together these data suggest that the chalcone 2,2′,5′-trihydroxychalcone can modulate neuroinflammatory activation in brain-derived microglia and holds promise as a therapeutic in neuroinflammatory conditions.

  2. Human endogenous retrovirus W env increases nitric oxide production and enhances the migration ability of microglia by regulating the expression of inducible nitric oxide synthase.

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    Xiao, Ran; Li, Shan; Cao, Qian; Wang, Xiuling; Yan, Qiujin; Tu, Xiaoning; Zhu, Ying; Zhu, Fan

    2017-06-01

    Human endogenous retrovirus W env (HERV-W env) plays a critical role in many neuropsychological diseases such as schizophrenia and multiple sclerosis (MS). These diseases are accompanied by immunological reactions in the central nervous system (CNS). Microglia are important immunocytes in brain inflammation that can produce a gasotransmitter-nitric oxide (NO). NO not only plays a role in the function of neuronal cells but also participates in the pathogenesis of various neuropsychological diseases. In this study, we reported increased NO production in CHME-5 microglia cells after they were transfected with HERV-W env. Moreover, HERV-W env increased the expression and function of human inducible nitric oxide synthase (hiNOS) and enhanced the promoter activity of hiNOS. Microglial migration was also enhanced. These data revealed that HERV-W env might contribute to increase NO production and microglial migration ability in neuropsychological disorders by regulating the expression of inducible NOS. Results from this study might lead to the identification of novel targets for the treatment of neuropsychological diseases, including neuroinflammatory diseases, stroke, and neurodegenerative diseases.

  3. Phospholipase D family member 4, a transmembrane glycoprotein with no phospholipase D activity, expression in spleen and early postnatal microglia.

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    Fumio Yoshikawa

    Full Text Available BACKGROUND: Phospholipase D (PLD catalyzes conversion of phosphatidylcholine into choline and phosphatidic acid, leading to a variety of intracellular signal transduction events. Two classical PLDs, PLD1 and PLD2, contain phosphatidylinositide-binding PX and PH domains and two conserved His-x-Lys-(x(4-Asp (HKD motifs, which are critical for PLD activity. PLD4 officially belongs to the PLD family, because it possesses two HKD motifs. However, it lacks PX and PH domains and has a putative transmembrane domain instead. Nevertheless, little is known regarding expression, structure, and function of PLD4. METHODOLOGY/PRINCIPAL FINDINGS: PLD4 was analyzed in terms of expression, structure, and function. Expression was analyzed in developing mouse brains and non-neuronal tissues using microarray, in situ hybridization, immunohistochemistry, and immunocytochemistry. Structure was evaluated using bioinformatics analysis of protein domains, biochemical analyses of transmembrane property, and enzymatic deglycosylation. PLD activity was examined by choline release and transphosphatidylation assays. Results demonstrated low to modest, but characteristic, PLD4 mRNA expression in a subset of cells preferentially localized around white matter regions, including the corpus callosum and cerebellar white matter, during the first postnatal week. These PLD4 mRNA-expressing cells were identified as Iba1-positive microglia. In non-neuronal tissues, PLD4 mRNA expression was widespread, but predominantly distributed in the spleen. Intense PLD4 expression was detected around the marginal zone of the splenic red pulp, and splenic PLD4 protein recovered from subcellular membrane fractions was highly N-glycosylated. PLD4 was heterologously expressed in cell lines and localized in the endoplasmic reticulum and Golgi apparatus. Moreover, heterologously expressed PLD4 proteins did not exhibit PLD enzymatic activity. CONCLUSIONS/SIGNIFICANCE: Results showed that PLD4 is a non

  4. Histamine induces microglia activation and dopaminergic neuronal toxicity via H1 receptor activation.

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    Rocha, Sandra M; Saraiva, Tatiana; Cristóvão, Ana C; Ferreira, Raquel; Santos, Tiago; Esteves, Marta; Saraiva, Cláudia; Je, Goun; Cortes, Luísa; Valero, Jorge; Alves, Gilberto; Klibanov, Alexander; Kim, Yoon-Seong; Bernardino, Liliana

    2016-06-04

    Histamine is an amine widely known as a peripheral inflammatory mediator and as a neurotransmitter in the central nervous system. Recently, it has been suggested that histamine acts as an innate modulator of microglial activity. Herein, we aimed to disclose the role of histamine in microglial phagocytic activity and reactive oxygen species (ROS) production and to explore the consequences of histamine-induced neuroinflammation in dopaminergic (DA) neuronal survival. The effect of histamine on phagocytosis was assessed both in vitro by using a murine N9 microglial cell line and primary microglial cell cultures and in vivo. Cells were exposed to IgG-opsonized latex beads or phosphatidylserine (PS) liposomes to evaluate Fcγ or PS receptor-mediated microglial phagocytosis, respectively. ROS production and protein levels of NADPH oxidases and Rac1 were assessed as a measure of oxidative stress. DA neuronal survival was evaluated in vivo by counting the number of tyrosine hydroxylase-positive neurons in the substantia nigra (SN) of mice. We found that histamine triggers microglial phagocytosis via histamine receptor 1 (H1R) activation and ROS production via H1R and H4R activation. By using apocynin, a broad NADPH oxidase (Nox) inhibitor, and Nox1 knockout mice, we found that the Nox1 signaling pathway is involved in both phagocytosis and ROS production induced by histamine in vitro. Interestingly, both apocynin and annexin V (used as inhibitor of PS-induced phagocytosis) fully abolished the DA neurotoxicity induced by the injection of histamine in the SN of adult mice in vivo. Blockade of H1R protected against histamine-induced Nox1 expression and death of DA neurons in vivo. Overall, our results highlight the relevance of histamine in the modulation of microglial activity that ultimately may interfere with neuronal survival in the context of Parkinson's disease (PD) and, eventually, other neurodegenerative diseases which are accompanied by microglia

  5. Sesquiterpene dimmer (DSF-27) inhibits the release of neuroinflammatory mediators from microglia by targeting spleen tyrosine kinase (Syk) and Janus kinase 2 (Jak2): Two major non-receptor tyrosine signaling proteins involved in inflammatory events

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    Zeng, Ke-Wu [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Wang, Shu [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Department of Medicinal Chemistry and Pharmaceutical Analysis, Logistics College of Chinese People' s Armed Police Forces, Tianjin 300162 (China); Dong, Xin; Jiang, Yong; Jin, Hong-Wei [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Tu, Peng-Fei, E-mail: pengfeitu@vip.163.com [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China)

    2014-03-15

    Non-receptor protein tyrosine kinases (NRPTKs)-dependent inflammatory signal transduction cascades play key roles in immunoregulation. However, drug intervention through NRPTKs-involved immunoregulation mechanism in microglia (the major immune cells of the central nervous system) has not been widely investigated. A main aim of the present study is to elucidate the contribution of two major NRPTKs (Syk and Jak2) in neuroinflammation suppression by a bioactive sesquiterpene dimmer (DSF-27). We found that LPS-stimulated BV-2 cells activated Syk and further initiated Akt/NF-κB inflammatory pathway. This Syk-dependent Akt/NF-κB inflammatory pathway can be effectively ameliorated by DSF-27. Moreover, Jak2 was activated by LPS, which was followed by transcriptional factor Stat3 activation. The Jak2/Stat3 signal was suppressed by DSF-27 through inhibition of Jak2 and Stat3 phosphorylation, promotion of Jak/Stat3 inhibitory factors PIAS3 expression, and down-regulation of ERK and p38 MAPK phosphorylation. Furthermore, DSF-27 protected cortical and mesencephalic dopaminergic neurons against neuroinflammatory injury. Taken together, our findings indicate NRPTK signaling pathways including Syk/NF-κB and Jak2/Stat3 cascades are potential anti-neuroinflammatory targets in microglia, and may also set the basis for the use of sesquiterpene dimmer as a therapeutic approach for neuroinflammation via interruption of these pathways. - Highlights: • Sesquiterpene dimmer DSF-27 inhibits inflammatory mediators' production in microglia. • Syk-dependent Akt/NF-κB pathway is important for DSF-27's anti-inflammation activity. • Jak2/Stat3 pathway is important for DSF-27's anti-inflammation activity. • Jak2/Stat3 signaling pathway is partly regulated by ERK and p38 MAPKs and PIAS3. • DSF-27 protects neurons against microglia-mediated neuroinflammatory injury.

  6. Activated Microglia Targeting Dendrimer-Minocycline Conjugate as Therapeutics for Neuroinflammation.

    Science.gov (United States)

    Sharma, Rishi; Kim, Soo-Young; Sharma, Anjali; Zhang, Zhi; Kambhampati, Siva Pramodh; Kannan, Sujatha; Kannan, Rangaramanujam M

    2017-11-15

    Brain-related disorders have outmatched cancer and cardiovascular diseases worldwide as the leading cause of morbidity and mortality. The lack of effective therapies and the relatively dry central nervous system (CNS) drug pipeline pose formidable challenge. Superior, targeted delivery of current clinically approved drugs may offer significant potential. Minocycline has shown promise for the treatment of neurological diseases owing to its ability to penetrate the blood-brain barrier (BBB) and potency. Despite its potential in the clinic and in preclinical models, the high doses needed to affect a positive therapeutic response have led to side effects. Targeted delivery of minocycline to the injured site and injured cells in the brain can be highly beneficial. Systemically administered hydroxyl poly(amidoamine) (PAMAM) generation-6 (G6) dendrimers have a longer blood circulation time and have been shown to cross the impaired BBB. We have successfully prepared and characterized the in vitro efficacy and in vivo targeting ability of hydroxyl-G6 PAMAM dendrimer-9-amino-minocycline conjugate (D-mino). Minocycline is a challenging drug to carry out chemical transformations due to its inherent instability. We used a combination of a highly efficient and mild copper catalyzed azide-alkyne click reaction (CuAAC) along with microwave energy to conjugate 9-amino-minocycline (mino) to the dendrimer surface via enzyme responsive linkages. D-mino was further evaluated for anti-inflammatory and antioxidant activity in lipopolysaccharides-activated murine microglial cells. D-mino conjugates enhanced the intracellular availability of the drug due to their rapid uptake, suppressed inflammatory cytokine tumor necrosis factor α (TNF-α) production, and reduced oxidative stress by suppressing nitric oxide production, all significantly better than the free drug. Fluorescently labeled dendrimer conjugate (Cy5-D-mino) was systematically administered (intravenous, 55 mg/kg) on postnatal

  7. Neuronal CCL2 is upregulated during hepatic encephalopathy and contributes to microglia activation and neurological decline.

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    McMillin, Matthew; Frampton, Gabriel; Thompson, Michelle; Galindo, Cheryl; Standeford, Holly; Whittington, Eric; Alpini, Gianfranco; DeMorrow, Sharon

    2014-07-10

    Acute liver failure leads to systemic complications with one of the most dangerous being a decline in neurological function, termed hepatic encephalopathy. Neurological dysfunction is exacerbated by an increase of toxic metabolites in the brain that lead to neuroinflammation. Following various liver diseases, hepatic and circulating chemokines, such as chemokine ligand 2 (CCL2), are elevated, though their effects on the brain following acute liver injury and subsequent hepatic encephalopathy are unknown. CCL2 is known to activate microglia in other neuropathies, leading to a proinflammatory response. However, the effects of CCL2 on microglia activation and the pathogenesis of hepatic encephalopathy following acute liver injury remain to be determined. Hepatic encephalopathy was induced in mice via injection of azoxymethane (AOM) in the presence or absence of INCB 3284 dimesylate (INCB), a chemokine receptor 2 inhibitor, or C 021 dihydrochloride (C021), a chemokine receptor 4 inhibitor. Mice were monitored for neurological decline and time to coma (loss of all reflexes) was recorded. Tissue was collected at coma and used for real-time PCR, immunoblots, ELISA, or immunostaining analyses to assess the activation of microglia and consequences on pro-inflammatory cytokine expression. Following AOM administration, microglia activation was significantly increased in AOM-treated mice compared to controls. Concentrations of CCL2 in the liver, serum, and cortex were significantly elevated in AOM-treated mice compared to controls. Systemic administration of INCB or C021 reduced liver damage as assessed by serum liver enzyme biochemistry. Administration of INCB or C021 significantly improved the neurological outcomes of AOM-treated mice, reduced microglia activation, reduced phosphorylation of ERK1/2, and alleviated AOM-induced cytokine upregulation. These findings suggest that CCL2 is elevated systemically following acute liver injury and that CCL2 is involved in both the

  8. Hippocampal activation of microglia may underlie the shared neurobiology of comorbid posttraumatic stress disorder and chronic pain.

    Science.gov (United States)

    Sun, Rao; Zhang, Zuoxia; Lei, Yishan; Liu, Yue; Lu, Cui'e; Rong, Hui; Sun, Yu'e; Zhang, Wei; Ma, Zhengliang; Gu, Xiaoping

    2016-01-01

    The high comorbidity rates of posttraumatic stress disorder and chronic pain have been widely reported, but the underlying mechanisms remain unclear. Emerging evidence suggested that an excess of inflammatory immune activities in the hippocampus involved in the progression of both posttraumatic stress disorder and chronic pain. Considering that microglia are substrates underlying the initiation and propagation of the neuroimmune response, we hypothesized that stress-induced activation of hippocampal microglia may contribute to the pathogenesis of posttraumatic stress disorder-pain comorbidity. We showed that rats exposed to single prolonged stress, an established posttraumatic stress disorder model, exhibited persistent mechanical allodynia and anxiety-like behavior, which were accompanied by increased activation of microglia and secretion of pro-inflammatory cytokines in the hippocampus. Correlation analyses showed that hippocampal activation of microglia was significantly correlated with mechanical allodynia and anxiety-like behavior. Our data also showed that both intraperitoneal and intra-hippocampal injection of minocycline suppressed single prolonged stress-induced microglia activation and inflammatory cytokines accumulation in the hippocampus, and attenuated both single prolonged stress-induced mechanical allodynia and anxiety-like behavior. Taken together, the present study suggests that stress-induced microglia activation in the hippocampus may serve as a critical mechanistic link in the comorbid relationship between posttraumatic stress disorder and chronic pain. The novel concept introduces the possibility of cotreating chronic pain and posttraumatic stress disorder. © The Author(s) 2016.

  9. Selective activation of microglia in spinal cord but not higher cortical regions following nerve injury in adult mouse

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    Shang Yuze

    2008-04-01

    Full Text Available Abstract Neuronal plasticity along the pathway for sensory transmission including the spinal cord and cortex plays an important role in chronic pain, including inflammatory and neuropathic pain. While recent studies indicate that microglia in the spinal cord are involved in neuropathic pain, a systematic study has not been performed in other regions of the central nervous system (CNS. In the present study, we used heterozygous Cx3cr1GFP/+mice to characterize the morphological phenotypes of microglia following common peroneal nerve (CPN ligation. We found that microglia showed a uniform distribution throughout the CNS, and peripheral nerve injury selectively activated microglia in the spinal cord dorsal horn and related ventral horn. In contrast, microglia was not activated in supraspinal regions of the CNS, including the anterior cingulate cortex (ACC, prefrontal cortex (PFC, primary and secondary somatosensory cortex (S1 and S2, insular cortex (IC, amygdala, hippocampus, periaqueductal gray (PAG and rostral ventromedial medulla (RVM. Our results provide strong evidence that nerve injury primarily activates microglia in the spinal cord of adult mice, and pain-related cortical plasticity is likely mediated by neurons.

  10. Microglia in Glia-Neuron Co-cultures Exhibit Robust Phagocytic Activity Without Concomitant Inflammation or Cytotoxicity.

    Science.gov (United States)

    Adams, Alexandra C; Kyle, Michele; Beaman-Hall, Carol M; Monaco, Edward A; Cullen, Matthew; Vallano, Mary Lou

    2015-10-01

    A simple method to co-culture granule neurons and glia from a single brain region is described, and microglia activation profiles are assessed in response to naturally occurring neuronal apoptosis, excitotoxin-induced neuronal death, and lipopolysaccharide (LPS) addition. Using neonatal rat cerebellar cortex as a tissue source, glial proliferation is regulated by omission or addition of the mitotic inhibitor cytosine arabinoside (AraC). After 7-8 days in vitro, microglia in AraC(-) cultures are abundant and activated based on their amoeboid morphology, expressions of ED1 and Iba1, and ability to phagocytose polystyrene beads and the majority of neurons undergoing spontaneous apoptosis. Microglia and phagocytic activities are sparse in AraC(+) cultures. Following exposure to excitotoxic kainate concentrations, microglia in AraC(-) cultures phagocytose most dead neurons within 24 h without exacerbating neuronal loss or mounting a strong or sustained inflammatory response. LPS addition induces a robust inflammatory response, based on microglial expressions of TNF-α, COX-2 and iNOS proteins, and mRNAs, whereas these markers are essentially undetectable in control cultures. Thus, the functional effector state of microglia is primed for phagocytosis but not inflammation or cytotoxicity even after kainate exposure that triggers death in the majority of neurons. This model should prove useful in studying the progressive activation states of microglia and factors that promote their conversion to inflammatory and cytotoxic phenotypes.

  11. Icariin Reduces Dopaminergic Neuronal Loss and Microglia-Mediated Inflammation in Vivo and in Vitro

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    Guo-Qing Wang

    2018-01-01

    Full Text Available Parkinson’s disease (PD is one of the most common neurodegenerative diseases characterized with a gradual loss of midbrain substantia nigra (SN dopamine (DA neurons. An excessive evidence demonstrated that microglia-mediated inflammation might be involved in the pathogenesis of PD. Thus, inhibition of neuroinflammation might possess a promising potential for PD treatment. Icariin (ICA, a single active component extracted from the Herba Epimedii, presents amounts of pharmacological properties, such as anti-inflammation, anti-oxidant, and anti-aging. Recent studies show ICA produced neuroprotection against brain dysfunction. However, the mechanisms underlying ICA-exerted neuroprotection are fully illuminated. In the present study, two different neurotoxins of 6-hydroxydopamine (6-OHDA and lipopolysaccharide (LPS-induced rat midbrain DA neuronal damage were applied to investigate the neuroprotective effects of ICA. In addition, primary rat midbrain neuron-glia co-cultures were performed to explore the mechanisms underlying ICA-mediated DA neuroprotection. In vitro data showed that ICA protected DA neurons from LPS/6-OHDA-induced DA neuronal damage and inhibited microglia activation and pro-inflammatory factors production via the suppression of nuclear factor-κB (NF-κB pathway activation. In animal results, ICA significantly reduced microglia activation and significantly attenuated LPS/6-OHDA-induced DA neuronal loss and subsequent animal behavior changes. Together, ICA could protect DA neurons against LPS- and 6-OHDA-induced neurotoxicity both in vivo and in vitro. These actions might be closely associated with the inhibition of microglia-mediated neuroinflammation.

  12. The established and emerging roles of astrocytes and microglia in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia.

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    Rowan Andrew Warren Radford

    2015-10-01

    Full Text Available Amyotrophic lateral sclerosis (ALS and Frontotemporal Dementia (FTD are two progressive, fatal neurodegenerative syndromes with considerable clinical, genetic and pathological overlap. Clinical symptoms of FTD can be seen in ALS patients and vice versa, recent genetic discoveries conclusive link the two diseases, and several common molecular players have been identified (TDP-43, FUS, C9ORF72.The definitive aetiologies of ALS and FTD are currently unknown and both disorders lack a cure. Glia, specifically astrocytes and microglia are heavily implicated in the onset and progression of neurodegeneration witnessed in ALS and FTD. In this review, we summarise the current understanding of the role of microglia and astrocytes involved in ALS and FTD, highlighting their recent implications in neuroinflammation, alterations in waste clearance involving phagocytosis and the newly described glymphatic system, and vascular abnormalities. Elucidating the precise mechanisms of how astrocytes and microglia are involved in ALS and FTD will be crucial in characterising these two disorders and may represent more effective interventions for disease progression and treatment options in the future.

  13. The established and emerging roles of astrocytes and microglia in amyotrophic lateral sclerosis and frontotemporal dementia.

    Science.gov (United States)

    Radford, Rowan A; Morsch, Marco; Rayner, Stephanie L; Cole, Nicholas J; Pountney, Dean L; Chung, Roger S

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two progressive, fatal neurodegenerative syndromes with considerable clinical, genetic and pathological overlap. Clinical symptoms of FTD can be seen in ALS patients and vice versa. Recent genetic discoveries conclusively link the two diseases, and several common molecular players have been identified (TDP-43, FUS, C9ORF72). The definitive etiologies of ALS and FTD are currently unknown and both disorders lack a cure. Glia, specifically astrocytes and microglia are heavily implicated in the onset and progression of neurodegeneration witnessed in ALS and FTD. In this review, we summarize the current understanding of the role of microglia and astrocytes involved in ALS and FTD, highlighting their recent implications in neuroinflammation, alterations in waste clearance involving phagocytosis and the newly described glymphatic system, and vascular abnormalities. Elucidating the precise mechanisms of how astrocytes and microglia are involved in ALS and FTD will be crucial in characterizing these two disorders and may represent more effective interventions for disease progression and treatment options in the future.

  14. The FTD-like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism.

    Science.gov (United States)

    Kleinberger, Gernot; Brendel, Matthias; Mracsko, Eva; Wefers, Benedikt; Groeneweg, Linda; Xiang, Xianyuan; Focke, Carola; Deußing, Maximilian; Suárez-Calvet, Marc; Mazaheri, Fargol; Parhizkar, Samira; Pettkus, Nadine; Wurst, Wolfgang; Feederle, Regina; Bartenstein, Peter; Mueggler, Thomas; Arzberger, Thomas; Knuesel, Irene; Rominger, Axel; Haass, Christian

    2017-07-03

    Genetic variants in the triggering receptor expressed on myeloid cells 2 (TREM2) increase the risk for several neurodegenerative diseases including Alzheimer's disease and frontotemporal dementia (FTD). Homozygous TREM2 missense mutations, such as p.T66M, lead to the FTD-like syndrome, but how they cause pathology is unknown. Using CRISPR/Cas9 genome editing, we generated a knock-in mouse model for the disease-associated Trem2 p.T66M mutation. Consistent with a loss-of-function mutation, we observe an intracellular accumulation of immature mutant Trem2 and reduced generation of soluble Trem2 similar to patients with the homozygous p.T66M mutation. Trem2 p.T66M knock-in mice show delayed resolution of inflammation upon in vivo lipopolysaccharide stimulation and cultured macrophages display significantly reduced phagocytic activity. Immunohistochemistry together with in vivo TSPO small animal positron emission tomography (μPET) demonstrates an age-dependent reduction in microglial activity. Surprisingly, perfusion magnetic resonance imaging and FDG-μPET imaging reveal a significant reduction in cerebral blood flow and brain glucose metabolism. Thus, we demonstrate that a TREM2 loss-of-function mutation causes brain-wide metabolic alterations pointing toward a possible function of microglia in regulating brain glucose metabolism. © 2017 The Authors.

  15. The translocator protein ligand [{sup 18}F]DPA-714 images glioma and activated microglia in vivo

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    Winkeler, Alexandra; Boisgard, Raphael; Awde, Ali R.; Dubois, Albertine; Theze, Benoit; Zheng, Jinzi [Universite Paris Sud, Inserm, U1023, Laboratoire d' Imagerie Moleculaire Experimentale, Orsay (France); CEA, I2BM, SHFJ, Orsay (France); Ciobanu, Luisa [CEA, DSV, I2BM, NeuroSpin, LRMN, Gif sur Yvette (France); Dolle, Frederic [CEA, I2BM, SHFJ, Orsay (France); Viel, Thomas; Jacobs, Andreas H. [Westfaelische Wilhelm-Universitaet Muenster (WWU), European Institute for Molecular Imaging (EIMI), Muenster (Germany); Tavitian, Bertrand [Universite Paris Sud, Inserm, U1023, Laboratoire d' Imagerie Moleculaire Experimentale, Orsay (France)

    2012-05-15

    In recent years there has been an increase in the development of radioligands targeting the 18-kDa translocator protein (TSPO). TSPO expression is well documented in activated microglia and serves as a biomarker for imaging neuroinflammation. In addition, TSPO has also been reported to be overexpressed in a number of cancer cell lines and human tumours including glioma. Here we investigated the use of [{sup 18}F]DPA-714, a new TSPO positron emission tomography (PET) radioligand to image glioma in vivo. We studied the uptake of [{sup 18}F]DPA-714 in three different rat strains implanted with 9L rat glioma cells: Fischer (F), Wistar (W) and Sprague Dawley (SD) rats. Dynamic [{sup 18}F]DPA-714 PET imaging, kinetic modelling of PET data and in vivo displacement studies using unlabelled DPA-714 and PK11195 were performed. Validation of TSPO expression in 9L glioma cell lines and intracranial 9L gliomas were investigated using Western blotting and immunohistochemistry of brain tissue sections. All rats showed significant [{sup 18}F]DPA-714 PET accumulation at the site of 9L tumour implantation compared to the contralateral brain hemisphere with a difference in uptake among the three strains (F > W > SD). The radiotracer showed high specificity for TSPO as demonstrated by the significant reduction of [{sup 18}F]DPA-714 binding in the tumour after administration of unlabelled DPA-714 or PK11195. TSPO expression was confirmed by Western blotting in 9L cells in vitro and by immunohistochemistry ex vivo. The TSPO radioligand [{sup 18}F]DPA-714 can be used for PET imaging of intracranial 9L glioma in different rat strains. This preclinical study demonstrates the feasibility of employing [{sup 18}F]DPA-714 as an alternative radiotracer to image human glioma. (orig.)

  16. Etiogenic factors present in the cerebrospinal fluid from amyotrophic lateral sclerosis patients induce predominantly pro-inflammatory responses in microglia.

    Science.gov (United States)

    Mishra, Pooja-Shree; Vijayalakshmi, K; Nalini, A; Sathyaprabha, T N; Kramer, B W; Alladi, Phalguni Anand; Raju, T R

    2017-12-16

    Microglial cell-associated neuroinflammation is considered as a potential contributor to the pathophysiology of sporadic amyotrophic lateral sclerosis. However, the specific role of microglia in the disease pathogenesis remains to be elucidated. We studied the activation profiles of the microglial cultures exposed to the cerebrospinal fluid from these patients which recapitulates the neurodegeneration seen in sporadic amyotrophic lateral sclerosis. This was done by investigating the morphological and functional changes including the expression levels of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), TNF-α, IL-6, IFN-γ, IL-10, inducible nitric oxide synthase (iNOS), arginase, and trophic factors. We also studied the effect of chitotriosidase, the inflammatory protein found upregulated in the cerebrospinal fluid from amyotrophic lateral sclerosis patients, on these cultures. We report that the cerebrospinal fluid from amyotrophic lateral sclerosis patients could induce an early and potent response in the form of microglial activation, skewed primarily towards a pro-inflammatory profile. It was seen in the form of upregulation of the pro-inflammatory cytokines and factors including IL-6, TNF-α, iNOS, COX-2, and PGE2. Concomitantly, a downregulation of beneficial trophic factors and anti-inflammatory markers including VEGF, glial cell line-derived neurotrophic factor, and IFN-γ was seen. In addition, chitotriosidase-1 appeared to act specifically via the microglial cells. Our findings demonstrate that the cerebrospinal fluid from amyotrophic lateral sclerosis patients holds enough cues to induce microglial inflammatory processes as an early event, which may contribute to the neurodegeneration seen in the sporadic amyotrophic lateral sclerosis. These findings highlight the dynamic role of microglial cells in the pathogenesis of the disease, thus suggesting the need for a multidimensional and temporally guarded therapeutic approach targeting the inflammatory

  17. Microglia: An Interface between the Loss of Neuroplasticity and Depression

    OpenAIRE

    Singhal, Gaurav; Baune, Bernhard T.

    2017-01-01

    Depression has been widely accepted as a major psychiatric disease affecting nearly 350 million people worldwide. Research focus is now shifting from studying the extrinsic and social factors of depression to the underlying molecular causes. Microglial activity is shown to be associated with pathological conditions, such as psychological stress, pathological aging, and chronic infections. These are primary immune effector cells in the CNS and regulate the extensive dialogue between the nervou...

  18. Paeoniflorin Suppressed High Glucose-Induced Retinal Microglia MMP-9 Expression and Inflammatory Response via Inhibition of TLR4/NF-κB Pathway Through Upregulation of SOCS3 in Diabetic Retinopathy.

    Science.gov (United States)

    Zhu, Su-Hua; Liu, Bing-Qian; Hao, Mao-Juan; Fan, Yi-Xin; Qian, Cheng; Teng, Peng; Zhou, Xiao-Wei; Hu, Liang; Liu, Wen-Tao; Yuan, Zhi-Lan; Li, Qing-Ping

    2017-10-01

    Diabetic retinopathy (DR) is a serious-threatening complication of diabetes and urgently needed to be treated. Evidence has accumulated indicating that microglia inflammation within the retina plays a critical role in DR. Microglial matrix metalloproteinase 9 (MMP-9) has an important role in the destruction of the integrity of the blood-retinal barrier (BRB) associated with the development of DR. MMP-9 was also considered important for regulating inflammatory responses. Paeoniflorin, a monoterpene glucoside, has a potent immunomodulatory effect on microglia. We hypothesized that paeoniflorin could significantly suppress microglial MMP-9 activation induced by high glucose and further relieve DR. BV2 cells were used to investigate the effects and mechanism of paeoniflorin. The activation of MMP-9 was measured by gelatin zymography. Cell signaling was measured by western blot assay and immunofluorescence assay. High glucose increased the activation of MMP-9 in BV2 cells, which was abolished by HMGB1, TLR4, p38 MAPK, and NF-κB inhibition. Phosphorylation of p38 MAPK induced by high glucose was decreased by TLR4 inhibition in BV2 cells. Paeoniflorin induced suppressor of cytokine signaling 3 (SOCS3) expression and reduced MMP-9 activation in BV2 cells. The effect of paeoniflorin on SOCS3 was abolished by the TLR4 inhibitor. In streptozotocin (STZ)-induced diabetes mice, paeoniflorin induced SOCS3 expression and reduced MMP-9 activation. Paeoniflorin suppressed STZ-induced IBA-1 and IL-1β expression and decreased STZ-induced high blood glucose level. In conclusion, paeoniflorin suppressed high glucose-induced retinal microglia MMP-9 expression and inflammatory response via inhibition of the TLR4/NF-κB pathway through upregulation of SOCS3 in diabetic retinopathy.

  19. Methyl salicylate 2-O-β-D-lactoside, a novel salicylic acid analogue, acts as an anti-inflammatory agent on microglia and astrocytes.

    Science.gov (United States)

    Lan, Xi; Liu, Rui; Sun, Lan; Zhang, Tiantai; Du, Guanhua

    2011-08-11

    Neuroinflammation has been known to play a critical role in the pathogenesis of Alzheimer's disease (AD). Activation of microglia and astrocytes is a characteristic of brain inflammation. Epidemiological studies have shown that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) delays the onset of AD and suppresses its progression. Methyl salicylate-2-O-β-D-lactoside (DL0309) is a new molecule chemically related to salicylic acid. The present study aimed to evaluate the anti-inflammatory effects of DL0309. Our studies show that DL0309 significantly inhibits lipopolysaccharide (LPS)-induced release of the pro-inflammatory cytokines IL-6, IL-1β, and TNF-α; and the expression of the inflammation-related proteins iNOS, COX-1, and COX-2 by microglia and astrocytes. At a concentration of 10 μM, DL0309 prominently inhibited LPS-induced activation of NF-κB in glial cells by blocking phosphorylation of IKK and p65, and by blocking IκB degradation. We demonstrate here for the first time that DL0309 exerts anti-inflammatory effects in glial cells by suppressing different pro-inflammatory cytokines and iNOS/NO. Furthermore, it also regulates the NF-κB signaling pathway by blocking IKK and p65 activation and IκB degradation. DL0309 also acts as a non-selective COX inhibitor in glial cells. These studies suggest that DL0309 may be effective in the treatment of neuroinflammatory disorders, including AD.

  20. Methyl salicylate 2-O-β-D-lactoside, a novel salicylic acid analogue, acts as an anti-inflammatory agent on microglia and astrocytes

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    Du Guanhua

    2011-08-01

    Full Text Available Abstract Background Neuroinflammation has been known to play a critical role in the pathogenesis of Alzheimer's disease (AD. Activation of microglia and astrocytes is a characteristic of brain inflammation. Epidemiological studies have shown that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs delays the onset of AD and suppresses its progression. Methyl salicylate-2-O-β-D-lactoside (DL0309 is a new molecule chemically related to salicylic acid. The present study aimed to evaluate the anti-inflammatory effects of DL0309. Findings Our studies show that DL0309 significantly inhibits lipopolysaccharide (LPS-induced release of the pro-inflammatory cytokines IL-6, IL-1β, and TNF-α; and the expression of the inflammation-related proteins iNOS, COX-1, and COX-2 by microglia and astrocytes. At a concentration of 10 μM, DL0309 prominently inhibited LPS-induced activation of NF-κB in glial cells by blocking phosphorylation of IKK and p65, and by blocking IκB degradation. Conclusions We demonstrate here for the first time that DL0309 exerts anti-inflammatory effects in glial cells by suppressing different pro-inflammatory cytokines and iNOS/NO. Furthermore, it also regulates the NF-κB signaling pathway by blocking IKK and p65 activation and IκB degradation. DL0309 also acts as a non-selective COX inhibitor in glial cells. These studies suggest that DL0309 may be effective in the treatment of neuroinflammatory disorders, including AD.

  1. Induction of Microglial Activation by Mediators Released from Mast Cells

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    Xiang Zhang

    2016-04-01

    Full Text Available Background/Aims: Microglia are the resident immune cells in the brain and play a pivotal role in immune surveillance in the central nervous system (CNS. Brain mast cells are activated in CNS disorders and induce the release of several mediators. Thus, brain mast cells, rather than microglia, are the “first responders” due to injury. However, the functional aspects of mast cell-microglia interactions remain uninvestigated. Methods: Conditioned medium from activated HMC-1 cells induces microglial activation similar to co-culture of microglia with HMC-1 cells. Primary cultured microglia were examined by flow cytometry analysis and confocal microscopy. TNF- alpha and IL-6 were measured with commercial ELISA kits. Cell signalling was analysed by Western blotting. Results: In the present study, we found that the conditioned medium from activated HMC-1 cells stimulated microglial activation and the subsequent production of the pro-inflammatory factors TNF-α and IL-6. Co-culture of microglia and HMC-1 cells with corticotropin-releasing hormone (CRH for 24, 48 and 72 hours increased TNF-α and IL-6 production. Antagonists of histamine receptor 1 (H1R, H4R, proteinase-activated receptor 2 (PAR2 or Toll-like receptor 4 (TLR4 reduced HMC-1-induced pro-inflammatory factor production and MAPK and PI3K/AKT pathway activation. Conclusions: These results imply that activated mast cells trigger microglial activation. Interactions between mast cells and microglia could constitute a new and unique therapeutic target for CNS inflammation-related diseases.

  2. Cytokine-producing microglia have an altered beta-amyloid load in aged APP/PS1 Tg mice

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    Babcock, Alicia A; Ilkjær, Laura; Clausen, Bettina H

    2015-01-01

    of CD11b, TNF, and IL-1Ra. Cytokine production and Aβ load were assessed in neocortical CD11b(+)(CD45(+)) microglia by flow cytometry. Whereas most microglia in aged mice produced IL-1Ra, relatively low proportions of microglia produced TNF, IL-1α, and IL-1β. However, microglial production......, however the inter-relationship between these processes is poorly understood. Here we show that % Aβ plaque load followed a sigmoidal trajectory with age in the neocortex of APPswe/PS1ΔE9 Tg mice, and correlated positively with soluble Aβ40 and Aβ42. Aβ measures were moderately correlated with mRNA levels...... of these latter cytokines was generally increased in APP/PS1 Tg mice. Microglia that phagocytosed endogenously-produced Aβ were only observed in APP/PS1 Tg mice. Differences in phagocytic index and total Aβ load were observed in microglia with specific cytokine profiles. Both phagocytic index and total Aβ load...

  3. Gemfibrozil, a lipid lowering drug, inhibits the activation of primary human microglia via peroxisome proliferator-activated receptor β.

    Science.gov (United States)

    Jana, Malabendu; Pahan, Kalipada

    2012-08-01

    Microglial activation participates in the pathogenesis of various neuroinflammatory and neurodegenerative diseases. However, mechanisms by which microglial activation could be controlled are poorly understood. Peroxisome proliferator-activated receptors (PPAR) are transcription factors belonging to the nuclear receptor super family with diverse effect. This study underlines the importance of PPARβ/δ in mediating the anti-inflammatory effect of gemfibrozil, an FDA-approved lipid-lowering drug, in primary human microglia. Bacterial lipopolysachharides (LPS) induced the expression of various proinflammatory molecules and upregulated the expression of microglial surface marker CD11b in human microglia. However, gemfibrozil markedly suppressed proinflammatory molecules and CD11b in LPS-stimulated microglia. Human microglia expressed PPAR-β and -γ, but not PPAR-α. Interestingly, either antisense knockdown of PPAR-β or antagonism of PPAR-β by a specific chemical antagonist abrogated gemfibrozil-mediated inhibition of microglial activation. On the other hand, blocking of PPAR-α and -γ had no effect on gemfibrozil-mediated anti-inflammatory effect in microglia. These results highlight the fact that gemfibrozil regulates microglial activation by inhibiting inflammatory gene expression in a PPAR-β dependent pathway and further reinforce its therapeutic application in several neuroinflammatory and neurodegenerative diseases.

  4. Gamma-Secretase Inhibitors Attenuate Neurotrauma and Neurogenic Acute Lung Injury in Rats by Rescuing the Accumulation of Hypertrophic Microglia

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    Hung-Jung Lin

    2017-12-01

    Full Text Available Background/Aims: In response to traumatic brain injury (TBI, activated microglia exhibit changes in their morphology from the resting ramified phenotype toward the activated hypertrophic or amoeboid phenotype. Here, we provide the first description of the mechanism underlying the neuroprotective effects of γ-secretase inhibitors on TBI outcomes in rats. Methods: The neuroprotective effects of γ-secretase inhibitors such as LY411575 or CHF5074 on TBI-induced neurotoxicity were analysed using a neurological motor function evaluation, cerebral contusion assay, immunohistochemical staining for microglia phenotypes, lung injury score and Evans Blue dye extravasation assay of brain and lung oedema. Results: Hypertrophic or amoeboid microglia accumulated in the injured cortex, the blood-brain-barrier was disrupted and neurological deficits and acute lung injury were observed 4 days after TBI in adult rats. However, a subcutaneous injection of LY411575 (5 mg/kg or CHF5074 (30 mg/kg immediately after TBI and once daily for 3 consecutive days post-TBI significantly attenutaed the accumulation of hypertrophic microglia in the injured brain, neurological injury, and neurogenic acute lung injury. Conclusion: Gamma-secretase inhibitors attenuated neurotrauma and neurogenic acute lung injury in rats by reducing the accumulation of hypertrophic microglia in the vicinity of the lesion.

  5. Deficiency of leptin receptor in myeloid cells disrupts hypothalamic metabolic circuits and causes body weight increase

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    Yuanqing Gao

    2018-01-01

    Conclusions: Myeloid cell leptin receptor deficient mice partially replicate the db/db phenotype. Leptin signaling in hypothalamic microglia is important for microglial function and a correct formation of the hypothalamic neuronal circuit regulating metabolism.

  6. Tumour-associated microglia/macrophages predict poor prognosis in high-grade gliomas and correlate with an aggressive tumour subtype

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    Sørensen, M D; Dahlrot, R H; Boldt, H B

    2018-01-01

    AIMS: Glioblastomas are highly aggressive and treatment resistant. Increasing evidence suggests that tumour-associated macrophages/microglia (TAMs) facilitate tumour progression by acquiring a M2-like phenotype. Our objective was to investigate the prognostic value of TAMs in gliomas using...... automated quantitative double immunofluorescence. METHODS: Samples from 240 patients with primary glioma were stained with antibodies against ionized calcium-binding adaptor molecule-1 (IBA-1) and cluster of differentiation 204 (CD204) to detect TAMs and M2-like TAMs. The expression levels were quantified...... by software-based classifiers. The associations between TAMs, gemistocytic cells and glioblastoma subtype were examined with immuno- and haematoxylin-eosin stainings. Three tissue arrays containing glioblastoma specimens were included to study IBA-1/CD204 levels in central tumour and tumour periphery...

  7. Estrogen alleviates neuropathic pain induced after spinal cord injury by inhibiting microglia and astrocyte activation.

    Science.gov (United States)

    Lee, Jee Youn; Choi, Hae Young; Ju, Bong-Gun; Yune, Tae Young

    2018-04-16

    Neuropathic pain after spinal cord injury (SCI) is developed in about 80% of SCI patients and there is no efficient therapeutic drug to alleviate SCI-induced neuropathic pain. Here we examined the effect of estrogen on SCI-induced neuropathic pain at below-level and its effect on neuroinflammation as underlying mechanisms. Neuropathic pain is developed at late phase after SCI and a single dose of 17β-estradiol (100, 300 μg/kg) were administered to rats with neuropathic pain after SCI through intravenous injection. As results, both mechanical allodynia and thermal hyperalgesia were significantly reduced by 17β-estradiol compared to vehicle control. Both microglia and astrocyte activation in the lamina I and II of L4-5 dorsal horn was also inhibited by 17β-estradiol. In addition, the levels of p-p38MAPK and p-ERK known to be activated in microglia and p-JNK known to be activated in astrocyte were significantly decreased by 17β-estradiol. Furthermore, the mRNA expression of inflammatory mediators such as Il-1β, Il-6, iNos, and Cox-2 was more attenuated in 17β-estradiol-treated group than in vehicle-treated group. Particularly, we found that the analgesic effect by 17β-estradiol was mediated via estrogen receptors, which are expressed in dorsal horn neurons. These results suggest that 17β-estradiol may attenuate SCI-induced neuropathic pain by inhibiting microglia and astrocyte activation followed inflammation. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. NOSH-NBP, a Novel Nitric Oxide and Hydrogen Sulfide- Releasing Hybrid, Attenuates Ischemic Stroke-Induced Neuroinflammatory Injury by Modulating Microglia Polarization

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    Jing Ji

    2017-05-01

    Full Text Available NOSH-NBP, a novel nitric oxide (NO and hydrogen sulfide (H2S-releasing hybrid, protects brain from ischemic stroke. This study mainly aimed to investigate the therapeutic effect of NOSH-NBP on ischemic stroke and the underlying mechanisms. In vivo, transient middle cerebral artery occlusion (tMCAO was performed in C57BL/6 mice, with NO-NBP and H2S-NBP as controls. NO and H2S scavengers, carboxy-PTIO and BSS, respectively, were used to quench NO and H2S of NOSH-NBP. In vitro, BV2 microglia/BMDM were induced to the M1/2 phenotype, and conditioned medium (CM experiments in BV2 microglia, neurons and b.End3 cerebral microvascular endothelial cells (ECs were performed. Microglial/macrophage activation/polarization was assessed by flow cytometry, Western blot, RT-qPCR, and ELISA. Neuronal and EC survival was measured by TUNEL, flow cytometry, MTT and LDH assays. Transmission electron microscopy, EB extravasation, brain water content, TEER measurement and Western blot were used to detect blood–brain barrier (BBB integrity and function. Interestingly, NOSH-NBP significantly reduced cerebral infarct volume and ameliorated neurological deficit, with superior effects compared with NO-NBP and/or H2S-NBP in mice after tMCAO. Both NO and H2S-releasing groups contributed to protection by NOSH-NBP. Additionally, NOSH-NBP decreased neuronal death and attenuated BBB dysfunction in tMCAO-treated mice. Furthermore, NOSH-NBP promoted microglia/macrophage switch from an inflammatory M1 phenotype to the protective M2 phenotype in vivo and in vitro. Moreover, the TLR4/MyD88/NF-κB pathway and NLRP3 inflammasome were involved in the inhibitory effects of NOSH-NBP on M1 polarization, while peroxisome proliferator activated receptor gamma signaling contributed to NOSH-NBP induced M2 polarization. These findings indicated that NOSH-NBP is a potential therapeutic agent that preferentially promotes microglial/macrophage M1–M2 switch in ischemic stroke.

  9. Microglia are required for astroglial toll-like receptor 4 response and for optimal TLR2 and TLR3 response

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    Holm, Thomas H; Draeby, Dina; Owens, Trevor

    2012-01-01

    Within the central nervous system, astrocytes and microglia are the primary responders to endogenous ligands released upon injury and stress, as well as to infectious pathogens. Toll-like receptors (TLRs) are implicated in recognition of both types of stimulus. Whether astrocytes respond as stron......Within the central nervous system, astrocytes and microglia are the primary responders to endogenous ligands released upon injury and stress, as well as to infectious pathogens. Toll-like receptors (TLRs) are implicated in recognition of both types of stimulus. Whether astrocytes respond...... astrocytes from mixed glial cultures and measured their response to TLR agonists. Our results show that the response of astrocytes to TLR2 and TLR3 agonists is greatly enhanced by, and response to TLR4 agonists is completely dependent on, the presence of functional microglia. In the case of the TLR4 response...

  10. Transient cerebral ischemia induces albumin expression in microglia only in the CA1 region of the gerbil hippocampus.

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    Park, Joon Ha; Park, Jin-A; Ahn, Ji Hyeon; Kim, Yang Hee; Kang, Il Jun; Won, Moo-Ho; Lee, Choong-Hyun

    2017-07-01

    Albumin, the most abundant plasma protein, is known to exhibit a neuroprotective effect in animal models of focal and global cerebral ischemia. In the present study, the expression and immunoreactivity of albumin was examined in the hippocampus following 5 min of transient cerebral ischemia in gerbils. Albumin immunoreactivity was observed in microglia of the CA1 hippocampal region 2 days post‑ischemic insult, and it was significantly increased at 4 days following ischemia-reperfusion. In addition, at 4 days post‑ischemic insult, albumin‑immunoreactive microglia were abundant in the stratum pyramidale of the CA1 region. The present results demonstrated that albumin was newly expressed post‑injury in microglia in the CA1 region, suggesting ischemia‑induced neuronal loss. Albumin expression may therefore be associated with ischemia‑induced delayed neuronal death in the CA1 region following transient cerebral ischemia.

  11. Microglia-Secreted Galectin-3 Acts as a Toll-like Receptor 4 Ligand and Contributes to Microglial Activation

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    Miguel Angel Burguillos

    2015-03-01

    Full Text Available Inflammatory response induced by microglia plays a critical role in the demise of neuronal populations in neuroinflammatory diseases. Although the role of toll-like receptor 4 (TLR4 in microglia’s inflammatory response is fully acknowledged, little is known about endogenous ligands that trigger TLR4 activation. Here, we report that galectin-3 (Gal3 released by microglia acts as an endogenous paracrine TLR4 ligand. Gal3-TLR4 interaction was further confirmed in a murine neuroinflammatory model (intranigral lipopolysaccharide [LPS] injection and in human stroke subjects. Depletion of Gal3 exerted neuroprotective and anti-inflammatory effects following global brain ischemia and in the neuroinflammatory LPS model. These results suggest that Gal3-dependent-TLR4 activation could contribute to sustained microglia activation, prolonging the inflammatory response in the brain.

  12. Contribution of microglia and astrocytes to the central sensitization, inflammatory and neuropathic pain in the juvenile rat

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    Ikeda Hiroshi

    2012-06-01

    Full Text Available Abstract Background The development of pain after peripheral nerve and tissue injury involves not only neuronal pathways but also immune cells and glia. Central sensitization is thought to be a mechanism for such persistent pain, and ATP involves in the process. We examined the contribution of glia to neuronal excitation in the juvenile rat spinal dorsal horn which is subjected to neuropathic and inflammatory pain. Results In rats subjected to neuropathic pain, immunoreactivity for the microglial marker OX42 was markedly increased. In contrast, in rats subjected to inflammatory pain, immunoreactivity for the astrocyte marker glial fibrillary acidic protein was increased slightly. Optically-recorded neuronal excitation induced by single-pulse stimulation to the dorsal root was augmented in rats subjected to neuropathic and inflammatory pain compared to control rats. The bath application of a glial inhibitor minocycline and a p38 mitogen-activated protein kinase inhibitor SB203580 inhibited the neuronal excitation in rats subjected to neuropathic pain. A specific P2X1,2,3,4 antagonist TNP-ATP largely inhibited the neuronal excitation only in rats subjected to neuropathic pain rats. In contrast, an astroglial toxin L-alpha-aminoadipate, a gap junction blocker carbenoxolone and c-Jun N-terminal kinase inhibitor SP600125 inhibited the neuronal excitation only in rats subjected to inflammatory pain. A greater number of cells in spinal cord slices from rats subjected to neuropathic pain showed Ca2+ signaling in response to puff application of ATP. This Ca2+ signaling was inhibited by minocycline and TNP-ATP. Conclusions These results directly support the notion that microglia is more involved in neuropathic pain and astrocyte in inflammatory pain.

  13. Mast cells in neuroinflammation and brain disorders

    NARCIS (Netherlands)

    Hendriksen, Erik|info:eu-repo/dai/nl/304841900; van Bergeijk, Doris; Oosting, Ronald S|info:eu-repo/dai/nl/087179695; Redegeld, Frank A|info:eu-repo/dai/nl/074752464

    2017-01-01

    It is well recognized that neuroinflammation is involved in the pathogenesis of various neurodegenerative diseases. Microglia and astrocytes are major pathogenic components within this process and known to respond to proinflammatory mediators released from immune cells such as mast cells. Mast cells

  14. p38 phosphorylation in medullary microglia mediates ectopic orofacial inflammatory pain in rats.

    Science.gov (United States)

    Kiyomoto, Masaaki; Shinoda, Masamichi; Honda, Kuniya; Nakaya, Yuka; Dezawa, Ko; Katagiri, Ayano; Kamakura, Satoshi; Inoue, Tomio; Iwata, Koichi

    2015-08-12

    Orofacial inflammatory pain is likely to accompany referred pain in uninflamed orofacial structures. The ectopic pain precludes precise diagnosis and makes treatment problematic, because the underlying mechanism is not well understood. Using the established ectopic orofacial pain model induced by complete Freund's adjuvant (CFA) injection into trapezius muscle, we analyzed the possible role of p38 phosphorylation in activated microglia in ectopic orofacial pain. Mechanical allodynia in the lateral facial skin was induced following trapezius muscle inflammation, which accompanied microglial activation with p38 phosphorylation and hyperexcitability of wide dynamic range (WDR) neurons in the trigeminal spinal subnucleus caudalis (Vc). Intra-cisterna successive administration of a p38 mitogen-activated protein kinase selective inhibitor, SB203580, suppressed microglial activation and its phosphorylation of p38. Moreover, SB203580 administration completely suppressed mechanical allodynia in the lateral facial skin and enhanced WDR neuronal excitability in Vc. Microglial interleukin-1β over-expression in Vc was induced by trapezius muscle inflammation, which was significantly suppressed by SB203580 administration. These findings indicate that microglia, activated via p38 phosphorylation, play a pivotal role in WDR neuronal hyperexcitability, which accounts for the mechanical hypersensitivity in the lateral facial skin associated with trapezius muscle inflammation.

  15. Microglia and their CX3CR1 signaling are involved in hippocampal- but not olfactory bulb-related memory and neurogenesis.

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    Reshef, Ronen; Kreisel, Tirzah; Beroukhim Kay, Dorsa; Yirmiya, Raz

    2014-10-01

    Recent studies demonstrate that microglia play an important role in cognitive and neuroplasticity processes, at least partly via microglial CX3C receptor 1 (CX3CR1) signaling. Furthermore, microglia are responsive to environmental enrichment (EE), which modulates learning, memory and neurogenesis. In the present study we examined the role of microglial CX3CR1 signaling in hippocampal- and olfactory-bulb (OB)-related memory and neurogenesis in homozygous mice with microglia-specific transgenic expression of GFP under the CX3CR1 promoter (CX3CR1(-/-) mice), in which the CX3CR1 gene is functionally deleted, as well as heterozygous CX3CR1(+/-) and WT controls. We report that the CX3CR1-deficient mice displayed better hippocampal-dependent memory functioning and olfactory recognition, along with increased number and soma size of hippocampal microglia, suggestive of mild activation status, but no changes in OB microglia. A similar increase in hippocampal-dependent memory functioning and microglia number was also induced by pharmacological inhibition of CX3CR1 signaling, using chronic (2weeks) i.c.v. administration of CX3CR1 blocking antibody. In control mice, EE improved hippocampal-dependent memory and neurogenesis, and increased hippocampal microglia number and soma size, whereas odor enrichment (OE) improved olfactory recognition and OB neurogenesis without changing OB microglia status. In CX3CR1-deficient mice, EE and OE did not produce any further improvement in memory functioning or neurogenesis and had no effect on microglial status. These results support the notion that in the hippocampus microglia and their interactions with neurons via the CX3CR1 play an important role in memory functioning and neurogenesis, whereas in the OB microglia do not seem to be involved in these processes. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Novel endogenous N-acyl amides activate TRPV1-4 receptors, BV-2 microglia, and are regulated in brain in an acute model of inflammation

    Science.gov (United States)

    Raboune, Siham; Stuart, Jordyn M.; Leishman, Emma; Takacs, Sara M.; Rhodes, Brandon; Basnet, Arjun; Jameyfield, Evan; McHugh, Douglas; Widlanski, Theodore; Bradshaw, Heather B.

    2014-01-01

    A family of endogenous lipids, structurally analogous to the endogenous cannabinoid, N-arachidonoyl ethanolamine (Anandamide), and called N-acyl amides have emerged as a family of biologically active compounds at TRP receptors. N-acyl amides are constructed from an acyl group and an amine via an amide bond. This same structure can be modified by changing either the fatty acid or the amide to form potentially hundreds of lipids. More than 70 N-acyl amides have been identified in nature. We have ongoing studies aimed at isolating and characterizing additional members of the family of N-acyl amides in both central and peripheral tissues in mammalian systems. Here, using a unique in-house library of over 70 N-acyl amides we tested the following three hypotheses: (1) Additional N-acyl amides will have activity at TRPV1-4, (2) Acute peripheral injury will drive changes in CNS levels of N-acyl amides, and (3) N-acyl amides will regulate calcium in CNS-derived microglia. Through these studies, we have identified 20 novel N-acyl amides that collectively activate (stimulating or inhibiting) TRPV1-4. Using lipid extraction and HPLC coupled to tandem mass spectrometry we showed that levels of at least 10 of these N-acyl amides that activate TRPVs are regulated in brain after intraplantar carrageenan injection. We then screened the BV2 microglial cell line for activity with this N-acyl amide library and found overlap with TRPV receptor activity as well as additional activators of calcium mobilization from these lipids. Together these data provide new insight into the family of N-acyl amides and their roles as signaling molecules at ion channels, in microglia, and in the brain in the context of inflammation. PMID:25136293

  17. Protection against septic shock and suppression of tumor necrosis factor alpha and nitric oxide production on macrophages and microglia by a standard aqueous extract of Mangifera indica L. (VIMANG). Role of mangiferin isolated from the extract.

    Science.gov (United States)

    Garrido, Gabino; Delgado, René; Lemus, Yeny; Rodríguez, Janet; García, Dagmar; Núñez-Sellés, Alberto J

    2004-08-01

    The present study illustrates the effects of a standard aqueous extract, used in Cuba under the brand name of VIMANG, from the stem bark of Mangifera indica L. on the production of tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) in in vivo and in vitro experiments. In vivo was determined by the action of the extract and its purified glucosylxanthone (mangiferin) on TNFalpha in a murine model of endotoxic shock using Balb/c mice pre-treated with lipopolysaccharide (LPS) 0.125 mg kg(-1), i.p. In vitro, M. indica extract and mangiferin were tested on TNFalpha and NO production in activated macrophages (RAW264.7 cell line) and microglia (N9 cell line) stimulated with LPS (10ng ml(-1)) and interferon gamma (IFNgamma, 2U ml(-1)). M. indica extract reduced dose-dependently TNFalpha production in the serum (ED50 = 64.5 mg kg(-1)) and the TNFalpha mRNA expression in the lungs and livers of mice. Mangiferin also inhibited systemic TNFalpha at 20 mg kg(-1). In RAW264.7, the extract inhibited TNFalpha (IC50 = 94.1 microg ml(-1)) and NO (IC50 = 64.4 microg ml(-1)). In microglia the inhibitions of the extract were IC50 = 76.0 microg ml(-1) (TNFalpha) and 84.0 microg ml(-1) (NO). These findings suggest that the anti-inflammatory response observed during treatment with M. indica extract must be related with inhibition of TNFalpha and NO production. Mangiferin, a main component in the extract, is involved in these effects. The TNFalpha and NO inhibitions by M. indica extract and mangiferin on endotoxic shock and microglia are reported here for the first time. Copyright 2004 Elsevier Ltd.

  18. Fractalkine Attenuates Microglial Cell Activation Induced by Prenatal Stress

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    Joanna Ślusarczyk

    2016-01-01

    Full Text Available The potential contribution of inflammation to the development of neuropsychiatric diseases has recently received substantial attention. In the brain, the main immune cells are the microglia. As they are the main source of inflammatory factors, it is plausible that the regulation of their activation may be a potential therapeutic target. Fractalkine (CX3CL1 and its receptor CX3CR1 play a crucial role in the control of the biological activity of the microglia. In the present study, using microglial cultures we investigated whether fractalkine is able to reverse changes in microglia caused by a prenatal stress procedure. Our study found that the microglia do not express fractalkine. Prenatal stress decreases the expression of the fractalkine receptor, which in turn is enhanced by the administration of exogenous fractalkine. Moreover, treatment with fractalkine diminishes the prenatal stress-induced overproduction of proinflammatory factors such as IL-1β, IL-18, IL-6, TNF-α, CCL2, or NO in the microglial cells derived from prenatally stressed newborns. In conclusion, the present results revealed that the pathological activation of microglia in prenatally stressed newborns may be attenuated by fractalkine administration. Therefore, understanding of the role of the CX3CL1-CX3CR1 system may help to elucidate the mechanisms underlying the neuron-microglia interaction and its role in pathological conditions in the brain.

  19. The organotin compounds trimethyltin (TMT) and triethyltin (TET) but not tributyltin (TBT) induce activation of microglia co-cultivated with astrocytes.

    Science.gov (United States)

    Röhl, C; Grell, M; Maser, E

    2009-12-01

    The organotin compounds trimethyltin (TMT), triethyltin (TET) and tributyltin (TBT) show different organotoxicities in vivo. While TMT and TET induce a strong neurotoxicity accompanied by microglial and astroglial activation, TBT rather effects the immune system. Previously, we have shown in an in vitro co-culture model that microglial cells can be activated by TMT in the presence of astrocytes. In this study, we wanted to investigate (a) if the neurotoxic organotin compound TET can also activate microglial cells in vitro similar to TMT and (b) if differences between the neurotoxicants TMT and TET on the one side and TBT on the other exist concerning microglial activation. Therefore, purified microglial and astroglial cell cultures from neonatal rat brains were treated either alone or in co-cultures for 24h with different concentrations of TMT, TET or TBT and the basal cytotoxicity and nitric oxide formation was determined. Furthermore, morphological changes of astrocytes were examined. Our results show that microglial activation can be increased in subcytolethal concentrations, but only in the presence of astrocytes and not in microglial cell cultures alone. This increase was induced by the neurotoxicants TMT and TET but not by TBT. Taken together, the differing microglia activating effect of the organotin compounds may contribute to the differing neurotoxic potential of this group of chemicals in vivo. In addition, our results emphasize the need for co-culture systems when studying interactions between different cell types for toxicity assessment.

  20. Anti-inflammatory effects of α-galactosylceramide analogs in activated microglia: involvement of the p38 MAPK signaling pathway.

    Directory of Open Access Journals (Sweden)

    Yeon-Hui Jeong

    Full Text Available Microglial activation plays a pivotal role in the development and progression of neurodegenerative diseases. Thus, anti-inflammatory agents that control microglial activation can serve as potential therapeutic agents for neurodegenerative diseases. Here, we designed and synthesized α-galactosylceramide (α-GalCer analogs to exert anti-inflammatory effects in activated microglia. We performed biological evaluations of 25 α-GalCer analogs and observed an interesting preliminary structure-activity relationship in their inhibitory influence on NO release and TNF-α production in LPS-stimulated BV2 microglial cells. After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis. We confirmed that 4d and 4e regulate the expression of iNOS, COX-2, IL-1β, and IL-6 at the mRNA level and the expression of TNF-α at the post-transcriptional level. In addition, both 4d and 4e inhibited LPS-induced DNA binding activities of NF-κB and AP-1 and phosphorylation of p38 MAPK without affecting other MAP kinases. When we examined the anti-inflammatory effect of a p38 MAPK-specific inhibitor, SB203580, on microglial activation, we observed an identical inhibitory pattern as that of 4d and 4e, not only on NO and TNF-α production but also on the DNA binding activities of NF-κB and AP-1. Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.

  1. Interleukin-4 ameliorates the functional recovery of intracerebral hemorrhage through the alternative activation of microglia/macrophage

    Directory of Open Access Journals (Sweden)

    Jianjing eYang

    2016-03-01

    Full Text Available Neuro-inflammation plays an important role in the recovery of brain injury after stroke. Microglia/macrophage is the major executor in the neuro-inflammation, which can be polarized into two distinct phenotypes: injurious/toxic classical activation (M1 phenotype and protective alternative activation (M2 phenotype. Here, we investigated whether intracerebral administration of interleukin-4 (IL-4 at an early stage could affect the activation of microglia/macrophage and the corresponding outcome after intracerebral hemorrhage (ICH. The neuro-behavior was recorded between different groups in the rat ICH model. The M1 and M2 markers were then determined by qRT-PCR, western blotting, ELISA and immunofluorescence, respectively. We observed aberrant activation of microglia/macrophage after ICH. After intracerebral injection of IL-4, M1 activation was greatly inhibited while M2 activation was enhanced, along with improving neurobehavioral recovery from deficits after ICH. Our study showed that early intracerebral injection of IL-4 potentially promotes neuro-functional recovery, probably through enhancing the alternative activation of microglia/macrophage.

  2. Adult human microglia secrete cytokines when exposed to neurotoxic prion protein peptide: no intermediary role for prostaglandin E2

    NARCIS (Netherlands)

    Veerhuis, Robert; Hoozemans, Jeroen J. M.; Janssen, Ingrid; Boshuizen, Ronald S.; Langeveld, Jan P. M.; Eikelenboom, Piet

    2002-01-01

    Prion diseases are characterized by accumulation of protease resistant isoforms of prion protein (termed PrP(SC)), glial activation and neurodegeneration. The time course of PrP deposition, appearance of activated microglia, and of neuronal apoptosis in experimentally-induced prion disease suggests

  3. Microglia and macrophages express tumor necrosis factor receptor p75 following middle cerebral artery occlusion in mice

    DEFF Research Database (Denmark)

    Lambertsen, Kate Lykke; Clausen, Bettina Hjelm; Fenger, Claus

    2007-01-01

    The proinflammatory and potential neurotoxic cytokine tumor necrosis factor (TNF) is produced by activated CNS resident microglia and infiltrating blood-borne macrophages in infarct and peri-infarct areas following induction of focal cerebral ischemia. Here, we investigated the expression of the ...

  4. Apolipoproteins E and J interfere with amyloid-beta uptake by primary human astrocytes and microglia in vitro

    NARCIS (Netherlands)

    Mulder, S.D.; Nielsen, H.M.; Blankenstein, M.A.; Eikelenboom, P.; Veerhuis, R.

    2014-01-01

    Defective clearance of the amyloid-β peptide (Aβ) from the brain is considered a strong promoter in Alzheimer's disease (AD) pathogenesis. Astrocytes and microglia are important mediators of Aβ clearance and Aβ aggregation state and the presence of amyloid associated proteins (AAPs), such as

  5. Tachykinin NK₁ receptor antagonist co-administration attenuates opioid withdrawal-mediated spinal microglia and astrocyte activation.

    Science.gov (United States)

    Tumati, Suneeta; Largent-Milnes, Tally M; Keresztes, Attila I; Yamamoto, Takashi; Vanderah, Todd W; Roeske, William R; Hruby, Victor J; Varga, Eva V

    2012-06-05

    Prolonged morphine treatment increases pain sensitivity in many patients. Enhanced spinal Substance P release is one of the adaptive changes associated with sustained opioid exposure. In addition to pain transmitting second order neurons, spinal microglia and astrocytes also express functionally active Tachykinin NK₁ (Substance P) receptors. In the present work we investigated the role of glial Tachykinin NK₁ receptors in morphine withdrawal-mediated spinal microglia and astrocyte activation. Our data indicate that intrathecal co-administration (6 days, twice daily) of a selective Tachykinin NK₁ receptor antagonist (N-acetyl-L-tryptophan 3,5-bis(trifluoromethyl)benzylester (L-732,138; 20 μg/injection)) attenuates spinal microglia and astrocyte marker and pro-inflammatory mediator immunoreactivity as well as hyperalgesia in withdrawn rats. Furthermore, covalent linkage of the opioid agonist with a Tachykinin NK₁ antagonist pharmacophore yielded a bivalent compound that did not augment spinal microglia or astrocyte marker or pro-inflammatory mediator immunoreactivity and did not cause paradoxical pain sensitization upon drug withdrawal. Thus, bivalent opioid/Tachykinin NK₁ receptor antagonists may provide a novel paradigm for long-term pain management.

  6. Sequential activation of microglia and astrocyte cytokine expression precedes increased Iba-1 or GFAP immunoreactivity following systemic immune challenge.

    Science.gov (United States)

    Norden, Diana M; Trojanowski, Paige J; Villanueva, Emmanuel; Navarro, Elisa; Godbout, Jonathan P

    2016-02-01

    Activation of the peripheral immune system elicits a coordinated response from the central nervous system. Key to this immune to brain communication is that glia, microglia, and astrocytes, interpret and propagate inflammatory signals in the brain that influence physiological and behavioral responses. One issue in glial biology is that morphological analysis alone is used to report on glial activation state. Therefore, our objective was to compare behavioral responses after in vivo immune (lipopolysaccharide, LPS) challenge to glial specific mRNA and morphological profiles. Here, LPS challenge induced an immediate but transient sickness response with decreased locomotion and social interaction. Corresponding with active sickness behavior (2-12 h), inflammatory cytokine mRNA expression was elevated in enriched microglia and astrocytes. Although proinflammatory cytokine expression in microglia peaked 2-4 h after LPS, astrocyte cytokine, and chemokine induction was delayed and peaked at 12 h. Morphological alterations in microglia (Iba-1(+)) and astrocytes (GFAP(+)), however, were undetected during this 2-12 h timeframe. Increased Iba-1 immunoreactivity and de-ramified microglia were evident 24 and 48 h after LPS but corresponded to the resolution phase of activation. Morphological alterations in astrocytes were undetected after LPS. Additionally, glial cytokine expression did not correlate with morphology after four repeated LPS injections. In fact, repeated LPS challenge was associated with immune and behavioral tolerance and a less inflammatory microglial profile compared with acute LPS challenge. Overall, induction of glial cytokine expression was sequential, aligned with active sickness behavior, and preceded increased Iba-1 or GFAP immunoreactivity after LPS challenge. © 2015 Wiley Periodicals, Inc.

  7. Amitriptyline induces brain-derived neurotrophic factor (BDNF) mRNA expression through ERK-dependent modulation of multiple BDNF mRNA variants in primary cultured rat cortical astrocytes and microglia.

    Science.gov (United States)

    Hisaoka-Nakashima, Kazue; Kajitani, Naoto; Kaneko, Masahiro; Shigetou, Takahiro; Kasai, Miho; Matsumoto, Chie; Yokoe, Toshiki; Azuma, Honami; Takebayashi, Minoru; Morioka, Norimitsu; Nakata, Yoshihiro

    2016-03-01

    A significant role of brain-derived neurotrophic factor (BDNF) has been previously implicated in the therapeutic effect of antidepressants. To ascertain the contribution of specific cell types in the brain that produce BDNF following antidepressant treatment, the effects of the tricyclic antidepressant amitriptyline on rat primary neuronal, astrocytic and microglial cortical cultures were examined. Amitriptyline increased the expression of BDNF mRNA in astrocytic and microglial cultures but not neuronal cultures. Antidepressants with distinct mechanisms of action, such as clomipramine, duloxetine and fluvoxamine, also increased BDNF mRNA expression in astrocytic and microglial cultures. There are multiple BDNF mRNA variants (exon I, IIA, IV and VI) expressed in astrocytes and microglia and the variant induced by antidepressants has yet to be elaborated. Treatment with antidepressants increased the expression of exon I, IV and VI in astrocyte and microglia. Clomipramine alone significantly upregulated expression of exon IIA. The amitriptyline-induced expression of both total and individual BDNF mRNA variants (exon I, IV and VI) were blocked by MEK inhibitor U0126, indicating MEK/ERK signaling is required in the expression of BDNF. These findings indicate that non-neural cells are a significant target of antidepressants and further support the contention that glial production of BDNF is crucial role in the therapeutic effect of antidepressants. The current data suggest that targeting of glial function could lead to the development of antidepressants with a truly novel mechanism of action. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Peripheral innate immune challenge exaggerated microglia activation, increased the number of inflammatory CNS macrophages, and prolonged social withdrawal in socially defeated mice.

    Science.gov (United States)

    Wohleb, Eric S; Fenn, Ashley M; Pacenta, Ann M; Powell, Nicole D; Sheridan, John F; Godbout, Jonathan P

    2012-09-01

    Repeated social defeat (RSD) activates neuroendocrine pathways that have a significant influence on immunity and behavior. Previous studies from our lab indicate that RSD enhances the inflammatory capacity of CD11b⁺ cells in the brain and promotes anxiety-like behavior in an interleukin (IL)-1 and β-adrenergic receptor-dependent manner. The purpose of this study was to determine the degree to which mice subjected to RSD were more responsive to a secondary immune challenge. Therefore, RSD or control (HCC) mice were injected with saline or lipopolysaccharide (LPS) and activation of brain CD11b⁺ cells and behavioral responses were determined. Peripheral LPS (0.5 mg/kg) injection caused an extended sickness response with exaggerated weight loss and prolonged social withdrawal in socially defeated mice. LPS injection also amplified mRNA expression of IL-1β, tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), and CD14 in enriched CD11b⁺ cells isolated from socially defeated mice. In addition, IL-1β mRNA levels in enriched CD11b⁺ cells remained elevated in socially defeated mice 24 h and 72 h after LPS. Moreover, microglia and CNS macrophages isolated from socially defeated mice had the highest CD14 expression after LPS injection. Both social defeat and LPS injection increased the percentage of CD11b⁺/CD45(high) macrophages in the brain and the number of inflammatory macrophages (CD11b⁺/CD45(high)/CCR2⁺) was highest in RSD-LPS mice. Anxiety-like behavior was increased by social defeat, but was not exacerbated by the LPS challenge. Nonetheless, reduced locomotor activity and increased social withdrawal were still present in socially defeated mice 72 h after LPS. Last, LPS-induced microglia activation was most evident in the hippocampus of socially defeated mice. Taken together, these findings demonstrate that repeated social defeat enhanced the neuroinflammatory response and caused prolonged sickness following innate immune challenge

  9. Estimation of absolute microglial cell numbers in mouse fascia dentata using unbiased and efficient stereological cell counting principles

    DEFF Research Database (Denmark)

    Wirenfeldt, Martin; Dalmau, Ishar; Finsen, Bente

    2003-01-01

    Stereology offers a set of unbiased principles to obtain precise estimates of total cell numbers in a defined region. In terms of microglia, which in the traumatized and diseased CNS is an extremely dynamic cell population, the strength of stereology is that the resultant estimate is unaffected...... of microglia, although with this thickness, the intensity of the staining is too high to distinguish single cells. Lectin histochemistry does not visualize microglia throughout the section and, accordingly, is not suited for the optical fractionator. The mean total number of Mac-1+ microglial cells...... in the unilateral dentate gyrus of the normal young adult male C57BL/6 mouse was estimated to be 12,300 (coefficient of variation (CV)=0.13) with a mean coefficient of error (CE) of 0.06. The perspective of estimating microglial cell numbers using stereology is to establish a solid basis for studying the dynamics...

  10. Anti-inflammatory and neuroprotective effect of a phytoestrogen compound on rat microglia.

    Science.gov (United States)

    Marotta, F; Mao, G S; Liu, T; Chui, D H; Lorenzetti, A; Xiao, Y; Marandola, P

    2006-11-01

    Ovariectomized Wistar rats received orally 15 mg/kg of a phytoestrogen compound (genistein, daidzein, glycitein, black cohosh, angelica sin., licorice, vitex agnus) for 2 weeks to test its ability to modulate inflammatory microglia response. Microglial proliferation was tested by trypan blue and by absorbance. Serial supernatant sampling was performed for 24 h to check TNF-alpha, IL-beta, IL-6, and TGF-beta. LPS caused a time course increase of all cytokines, with IL-beta and TNF-alpha peaking at the 12th hour, whereas IL-6 and TGF-beta peaked at the 24 h observation. Rats fed with the phytoestrogen displayed a significantly lower level of proinflammatory cytokines and a higher level of TGF-beta, as shown also by Western blot analysis. This finding may offer promise in the field of nutraceutical intervention.

  11. TNF-alpha expression by resident microglia and infiltrating leukocytes in the central nervous system of mice with experimental allergic encephalomyelitis

    DEFF Research Database (Denmark)

    Renno, T; Krakowski, M; Piccirillo, C

    1995-01-01

    in the pathology of multiple sclerosis and its animal model experimental allergic encephalomyelitis (EAE). We used reverse transcriptase (RT)-PCR to study the kinetics, cellular source, and regulation of cytokine gene expression in the central nervous system (CNS) of SJL/J mice with myelin basic protein......, the majority of which were identified as microglia and macrophages by their Mac-1 phenotype. Microglia could be discriminated by their low expression of CD45. Incubation of freshly derived, adult microglia from normal, uninfiltrated, CNS with activated Th1 supernatant induced the production of TNF-alpha m...

  12. 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine inhibit TNF-α and CXCL10 production from activated primary murine microglia via A2A receptors.

    Science.gov (United States)

    Newell, Elizabeth A; Exo, Jennifer L; Verrier, Jonathan D; Jackson, Travis C; Gillespie, Delbert G; Janesko-Feldman, Keri; Kochanek, Patrick M; Jackson, Edwin K

    2015-01-12

    Some cells, tissues and organs release 2',3'-cAMP (a positional isomer of 3',5'-cAMP) and convert extracellular 2',3'-cAMP to 2'-AMP plus 3'-AMP and convert these AMPs to adenosine (called the extracellular 2',3'-cAMP-adenosine pathway). Recent studies show that microglia have an extracellular 2',3'-cAMP-adenosine pathway. The goal of the present study was to investigate whether the extracellular 2',3'-cAMP-adenosine pathway could have functional consequences on the production of cytokines/chemokines by activated microglia. Experiments were conducted in cultures of primary murine microglia. In the first experiment, the effect of 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine on LPS-induced TNF-α and CXCL10 production was determined. In the next experiment, the first protocol was replicated but with the addition of 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX) (0.1 μM; antagonist of adenosine receptors). The last experiment compared the ability of 2-chloro-N(6)-cyclopentyladenosine (CCPA) (10 μM; selective A1 agonist), 5'-N-ethylcarboxamide adenosine (NECA) (10 μM; agonist for all adenosine receptor subtypes) and CGS21680 (10 μM; selective A2A agonist) to inhibit LPS-induced TNF-α and CXCL10 production. (1) 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine similarly inhibited LPS-induced TNF-α and CXCL10 production; (2) DPSPX nearly eliminated the inhibitory effects of 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine on LPS-induced TNF-α and CXCL10 production; (3) CCPA did not affect LPS-induced TNF-α and CXCL10; (4) NECA and CGS21680 similarly inhibited LPS-induced TNF-α and CXCL10 production. 2',3'-cAMP and its metabolites (3'-AMP, 2'-AMP and adenosine) inhibit LPS-induced TNF-α and CXCL10 production via A2A-receptor activation. Adenosine and its precursors, via A2A receptors, likely suppress TNF-α and CXCL10 production by activated microglia in brain diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. 2’,3’-cAMP, 3’-AMP, 2’-AMP and Adenosine Inhibit TNF-α and CXCL10 Production From Activated Primary Murine Microglia via A2A Receptors

    Science.gov (United States)

    Newell, Elizabeth A.; Exo, Jennifer L.; Verrier, Jonathan D.; Jackson, Travis C.; Gillespie, Delbert G.; Janesko-Feldman, Keri; Kochanek, Patrick M.

    2014-01-01

    Background Some cells, tissues and organs release 2’,3’-cAMP (a positional isomer of 3’,5’-cAMP) and convert extracellular 2’,3’-cAMP to 2’-AMP plus 3’-AMP and convert these AMPs to adenosine (called the extracellular 2’,3’-cAMP-adenosine pathway). Recent studies show that microglia have an extracellular 2’,3’-cAMP-adenosine pathway. The goal of the present study was to investigate whether the extracellular 2’,3’-cAMP-adenosine pathway could have functional consequences on the production of cytokines/chemokines by activated microglia. Methods Experiments were conducted in cultures of primary murine microglia. In the first experiment, the effect of 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine on LPS-induced TNF-α and CXCL10 production was determined. In the next experiment, the first protocol was replicated but with the addition of 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX) (0.1 µM; antagonist of adenosine receptors). The last experiment compared the ability of 2-chloro-N6-cyclopentyladenosine (CCPA) (10 µM; selective A1 agonist), 5’-N-ethylcarboxamide adenosine (NECA) (10 µM; agonist for all adenosine receptor subtypes) and CGS21680 (10 µM; selective A2A agonist) to inhibit LPS-induced TNF-α and CXCL10 production. Results 1) 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine similarly inhibited LPS-induced TNF-α and CXCL10 production; 2) DPSPX nearly eliminated the inhibitory effects of 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine on LPS-induced TNF-α and CXCL10 production; 3) CCPA did not affect LPS-induced TNF-α and CXCL10; 4) NECA and CGS21680 similarly inhibited LPS-induced TNF-α and CXCL10 production. Conclusions 2’,3’-cAMP and its metabolites (3’-AMP, 2’-AMP and adenosine) inhibit LPS-induced TNF-α and CXCL10 production via A2A-receptor activation. Adenosine and its precursors, via A2A receptors, likely suppress TNF-α and CXCL10 production by activated microglia in brain diseases. PMID:25451117

  14. Glial Cells: The Other Cells of the Nervous System-Microglia–The ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 10. Glial Cells: The Other Cells of the Nervous System - Microglia – The Guardians of the CNS. Medha S Rajadhyaksha Daya Manghani. Series Article Volume 7 Issue 10 October 2002 pp 23-29 ...

  15. Anti-Inflammatory Effect of Methylpenicinoline from a Marine Isolate of Penicillium sp. (SF-5995: Inhibition of NF-κB and MAPK Pathways in Lipopolysaccharide-Induced RAW264.7 Macrophages and BV2 Microglia

    Directory of Open Access Journals (Sweden)

    Dong-Cheol Kim

    2014-11-01

    Full Text Available In the course of a search for anti-inflammatory metabolites from marine-derived fungi, methylpenicinoline (1 was isolated from a marine isolate of Penicillin sp. Compound 1 inhibited lipopolysaccharide (LPS-stimulated nitric oxide (NO production by suppressing the expression of inducible NO synthase (iNOS in RAW264.7 macrophages and BV2 microglia. It also attenuated prostaglandin E2 (PGE2 production by suppressing cyclooxygenase-2 (COX-2 expression in a concentration-dependent manner (from 10 μM to 80 μM without affecting cell viability. In addition, compound 1 reduced the production of the pro-inflammatory cytokine interleukin-1β (IL-1β. In a further study designed to elucidate the mechanism of its anti-inflammatory effects, compound 1 was shown to block nuclear factor-kappa B (NF-κB activation in LPS-induced RAW264.7 macrophages and BV2 microglia by inhibiting the phosphorylation of inhibitor kappa B-α (IκB-α, thereby suppressing the nuclear translocation of NF-κB dimers, namely p50 and p65, that are known to be crucial molecules associated with iNOS and COX-2 expression. In addition, compound 1 inhibited the activation of mitogen-activated protein kinase (MAPK pathways. Taken together, the results suggest that compound 1 might be a valuable therapeutic agent for the treatment of anti-inflammatory and anti-neuroinflammatory diseases.

  16. Protective Effect of Cactus Cladode Extracts on Peroxisomal Functions in Microglial BV-2 Cells Activated by Different Lipopolysaccharides

    OpenAIRE

    Saih, Fatima-Ezzahra; Andreoletti, Pierre; Mandard, Stéphane; Latruffe, Norbert; El Kebbaj, M'Hammed Saïd; Lizard, Gérard; Nasser, Boubker; Cherkaoui-Malki, Mustapha

    2017-01-01

    International audience; In this study, we aimed to evaluate the antioxidant and anti-inflammatory properties of Opuntia ficus-indica cactus cladode extracts in microglia BV-2 cells. Inflammation associated with microglia activation in neuronal injury can be achieved by LPS exposure. Using four different structurally and biologically well-characterized LPS serotypes, we revealed a structure-related differential effect of LPS on fatty acid β-oxidation and antioxidant enzymes in peroxisomes: Esc...

  17. Quinolinic acid induced neurodegeneration in the striatum: a combined in vivo and in vitro analysis of receptor changes and microglia activation

    International Nuclear Information System (INIS)

    Moresco, R.M.; Lavazza, T.; Belloli, S.; Todde, S.; Matarrese, M.; Carpinelli, A.; Turolla, E.; Fazio, F.; Lecchi, M.; Pezzola, A.; Popoli, P.; Zimarino, V.; Malgaroli, A.

    2008-01-01

    Huntington's disease (HD) is a progressive neurodegenerative disorder, which is characterised by prominent neuronal cell loss in the basal ganglia with motor and cognitive disturbances. One of the most well-studied pharmacological models of HD is produced by local injection in the rat brain striatum of the excitotoxin quinolinic acid (QA), which produces many of the distinctive features of this human neurodegenerative disorder. Here, we report a detailed analysis, obtained both in vivo and in vitro of this pharmacological model of HD. By combining emission tomography (PET) with autoradiographic and immunocytochemical confocal laser techniques, we quantified in the QA-injected striatum the temporal behavior (from 1 to 60 days from the excitotoxic insult) of neuronal cell density and receptor availability (adenosine A 2A and dopamine D 2 receptors) together with the degree of microglia activation. Both approaches showed a loss of adenosine A 2A and dopamine D 2 receptors paralleled by an increase of microglial activation. This combined longitudinal analysis of the disease progression, which suggested an impairment of neurotransmission, neuronal integrity and a reversible activation of brain inflammatory processes, might represent a more quantitative approach to compare the differential effects of treatments in slowing down or reversing HD in rodent models with potential applications to human patients. (orig.)

  18. Having a Coffee Break: The Impact of Caffeine Consumption on Microglia-Mediated Inflammation in Neurodegenerative Diseases.

    Science.gov (United States)

    Madeira, Maria H; Boia, Raquel; Ambrósio, António F; Santiago, Ana R

    2017-01-01

    Caffeine is the major component of coffee and the most consumed psychostimulant in the world and at nontoxic doses acts as a nonselective adenosine receptor antagonist. Epidemiological evidence suggests that caffeine consumption reduces the risk of several neurological and neurodegenerative diseases. However, despite the beneficial effects of caffeine consumption in human health and behaviour, the mechanisms by which it impacts the pathophysiology of neurodegenerative diseases still remain to be clarified. A promising hypothesis is that caffeine controls microglia-mediated neuroinflammatory response associated with the majority of neurodegenerative conditions. Accordingly, it has been already described that the modulation of adenosine receptors, namely, the A 2A receptor, affords neuroprotection through the control of microglia reactivity and neuroinflammation. In this review, we will summarize the main effects of caffeine in the modulation of neuroinflammation in neurodegenerative diseases.

  19. Having a Coffee Break: The Impact of Caffeine Consumption on Microglia-Mediated Inflammation in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Maria H. Madeira

    2017-01-01

    Full Text Available Caffeine is the major component of coffee and the most consumed psychostimulant in the world and at nontoxic doses acts as a nonselective adenosine receptor antagonist. Epidemiological evidence suggests that caffeine consumption reduces the risk of several neurological and neurodegenerative diseases. However, despite the beneficial effects of caffeine consumption in human health and behaviour, the mechanisms by which it impacts the pathophysiology of neurodegenerative diseases still remain to be clarified. A promising hypothesis is that caffeine controls microglia-mediated neuroinflammatory response associated with the majority of neurodegenerative conditions. Accordingly, it has been already described that the modulation of adenosine receptors, namely, the A2A receptor, affords neuroprotection through the control of microglia reactivity and neuroinflammation. In this review, we will summarize the main effects of caffeine in the modulation of neuroinflammation in neurodegenerative diseases.

  20. Xinnao Shutong Modulates the Neuronal Plasticity Through Regulation of Microglia/Macrophage Polarization Following Chronic Cerebral Hypoperfusion in Rats

    Directory of Open Access Journals (Sweden)

    Liye Wang

    2018-05-01

    Full Text Available Xinnao shutong (XNST capsules have been clinically used in China to treat cerebrovascular diseases. Previous studies have demonstrated that XNST has significant neuroprotective effects against acute cerebral ischemic stroke. The present study investigated the effects and mechanisms of XNST treatment following chronic cerebral hypoperfusion. Thirty-six adult male Sprague-Dawley rats were treated with XNST or vehicle following permanent bilateral common carotid artery (BCCA ligation. Body weight was recorded on days 0, 3, 7, 14, 28, and 42 post-surgery. The Morris water maze (MWM test was used to assess cognitive function in rats. Immunofluorescent staining and western blot were used to assess the severity of neuronal plasticity, white matter injury, and the numbers and/or phenotypic changes incurred to microglia. Protein levels of p-AKT (Thr308 and p-ERK (Thr202/Tyr204 were detected 42 days after BCCA ligation was performed. The results indicate that XNST treatment significantly reduced escape latency, decreased the frequency of platform crossing compared to the vehicle group. Synaptophysin, protein levels improved and white matter injury ameliorated following XNST treatment. Meanwhile, XNST reduced the number of M1 microglia and increased the number of M2 microglia. Furthermore, p-AKT (Thr308 and p-ERK (Thr202/Tyr204 levels were increased 42 days following BCCA ligation. In summary, our results suggest that XNST mitigates memory impairments by restoration of neuronal plasticity and by modulation of microglial polarization following chronic cerebral hypoperfusion in rats.

  1. Hypoxia-inducible factor-1α upregulation in microglia following hypoxia protects against ischemia-induced cerebral infarction.

    Science.gov (United States)

    Huang, Tao; Huang, Weiyi; Zhang, Zhiqiang; Yu, Lei; Xie, Caijun; Zhu, Dongan; Peng, Zizhuang; Chen, Jiehan

    2014-10-01

    Activated microglia were considered to be the toxic inflammatory mediators that induce neuron degeneration after brain ischemia. Hypoxia can enhance the expression of hypoxia-inducible factor-1α (HIF-1α) in microglia and cause microglial activation. However, intermittent hypoxia has been reported recently to be capable of protecting the body from myocardial ischemia. We established a high-altitude environment as the hypoxic condition in this study. The hypoxic condition displayed a neuroprotective effect after brain ischemia, and mice exposed to this condition presented better neurological performance and smaller infarct size. At the same time, a high level of HIF-1α, low level of isoform of nitric oxide synthase, and a reduction in microglial activation were also seen in ischemic focus of hypoxic mice. However, this neuroprotective effect could be blocked by 2-methoxyestradiol, the HIF-1α inhibitor. Our finding suggested that HIF-1α expression was involved in microglial activation in vitro and was regulated by oxygen supply. The microglia were inactivated by re-exposure to hypoxia, which might be due to overexpression of HIF-1α. These results indicated that hypoxic conditions can be exploited to achieve maximum neuroprotection after brain ischemia. This mechanism possibly lies in microglial inactivation through regulation of the expression of HIF-1α.

  2. P2Y12 receptor-mediated activation of spinal microglia and p38MAPK pathway contribute to cancer-induced bone pain

    Directory of Open Access Journals (Sweden)

    Liu MJ

    2017-02-01

    Full Text Available Mingjuan Liu,1 Ming Yao,1,2 Hanqi Wang,1 Longsheng Xu,1 Ying Zheng,1 Bing Huang,1 Huadong Ni,1 Shijie Xu,1 Xuyan Zhou,1 Qingquan Lian2 1Department of Anesthesiology and Pain Medicine, The First Hospital of Jiaxing, The First Affiliated Hospital of Jiaxing University, Jiaxing, 2Department of Anesthesiology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China Background: Cancer-induced bone pain (CIBP is one of the most challenging clinical problems due to a lack of understanding the mechanisms. Recent evidence has demonstrated that activation of microglial G-protein-coupled P2Y12 receptor (P2Y12R and proinflammatory cytokine production play an important role in neuropathic pain generation and maintenance. However, whether P2Y12R is involved in CIBP remains unknown.Methods: The purpose of this study was to investigate the role of P2Y12R in CIBP and its molecular mechanisms. Using the bone cancer model inoculated with Walker 256 tumor cells into the left tibia of Sprague Dawley rat, we blocked spinal P2Y12R through intrathecal administration of its selective antagonist MRS2395 (400 pmol/µL, 15 µL.Results: We found that not only the ionized calcium-binding adapter molecule 1 (Iba-1-positive microglia in the ipsilateral spinal cord but also mechanical allodynia was significantly inhibited. Furthermore, it decreased the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK and the production of proinflammatory cytokines interleukin-1β (IL-1β and interleukin-6 (IL-6, whereas it increased tumor necrosis factor-α (TNF-α.Conclusion: Taken together, our present results suggest that microglial P2Y12R in the spinal cord may contribute to CIBP by the activation of spinal microglia and p38MAPK pathway, thus identifying a potential therapeutic target for the treatment of CIBP. Keywords: P2Y12 receptor, cancer-induced bone pain, p38MAPK pathway, cytokines

  3. Herpes simplex virus induces neural oxidative damage via microglial cell Toll-like receptor-2

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    Little Morgan R

    2010-06-01

    Full Text Available Abstract Background Using a murine model of herpes simplex virus (HSV-1 encephalitis, our laboratory has determined that induction of proinflammatory mediators in response to viral infection is largely mediated through a Toll-like receptor-2 (TLR2-dependent mechanism. Published studies have shown that, like other inflammatory mediators, reactive oxygen species (ROS are generated during viral brain infection. It is increasingly clear that ROS are responsible for facilitating secondary tissue damage during central nervous system infection and may contribute to neurotoxicity associated with herpes encephalitis. Methods Purified microglial cell and mixed neural cell cultures were prepared from C57B/6 and TLR2-/- mice. Intracellular ROS production in cultured murine microglia was measured via 2', 7'-Dichlorofluorescin diacetate (DCFH-DA oxidation. An assay for 8-isoprostane, a marker of lipid peroxidation, was utilized to measure free radical-associated cellular damage. Mixed neural cultures obtained from β-actin promoter-luciferase transgenic mice were used to detect neurotoxicity induced by HSV-infected microglia. Results Stimulation with HSV-1 elevated intracellular ROS in wild-type microglial cell cultures, while TLR2-/- microglia displayed delayed and attenuated ROS production following viral infection. HSV-infected TLR2-/- microglia produced less neuronal oxidative damage to mixed neural cell cultures in comparison to HSV-infected wild-type microglia. Further, HSV-infected TLR2-/- microglia were found to be less cytotoxic to cultured neurons compared to HSV-infected wild-type microglia. These effects were associated with decreased activation of p38 MAPK and p42/p44 ERK in TLR2-/- mice. Conclusions These studies demonstrate the importance of microglial cell TLR2 in inducing oxidative stress and neuronal damage in response to viral infection.

  4. α-Asarone Attenuates Cognitive Deficit in a Pilocarpine-Induced Status Epilepticus Rat Model via a Decrease in the Nuclear Factor-κB Activation and Reduction in Microglia Neuroinflammation

    Directory of Open Access Journals (Sweden)

    Hui-juan Liu

    2017-12-01

    Full Text Available BackgroundTemporal lobe epilepsy (TLE is one of the most drug-resistant types of epilepsy with about 80% of TLE patients falling into this category. Increasing evidence suggests that neuroinflammation, which has a critical role in the epileptogenesis of TLE, is associated with microglial activation. Therefore, agents that act toward the alleviation in microglial activation and the attenuation of neuroinflammation are promising candidates to treat TLE. α-Asarone is a major active ingredient of the Acori Graminei Rhizoma used in Traditional Chinese Medicine, which has been used to improve various disease conditions including stroke and convulsions. In addition, an increasing number of studies suggested that α-asarone can attenuate microglia-mediated neuroinflammation. Thus, we hypothesized that α-asarone is a promising neuroprotective agent for the treatment of the TLE.MethodsThe present study evaluated the therapeutic effects of α-asarone on microglia-mediated neuroinflammation and neuroprotection in vitro and in vivo, using an untreated control group, a status epilepticus (SE-induced group, and an SE-induced α-asarone pretreated group. A pilocarpine-induced rat model of TLE was established to investigate the neuroprotective effects of α-asarone in vivo. For the in vitro study, lipopolysaccharide (LPS-stimulated primary cultured microglial cells were used.ResultsThe results indicated that the brain microglial activation in the rats of the SE rat model led to important learning and memory deficit. Preventive treatment with α-asarone restrained microglial activation and reduced learning and memory deficit. In the in vitro studies, α-asarone significantly suppressed proinflammatory cytokine production in primary cultured microglial cells and attenuated the LPS-stimulated neuroinflammatory responses. Our mechanistic study revealed that α-asarone inhibited inflammatory processes by regulation the transcription levels of kappa-B, by blocking

  5. Different distribution patterns of lymphocytes and microglia in the hippocampus of patients with residual versus paranoid schizophrenia: further evidence for disease course-related immune alterations?

    Science.gov (United States)

    Busse, Stefan; Busse, Mandy; Schiltz, Kolja; Bielau, Hendrik; Gos, Tomasz; Brisch, Ralf; Mawrin, Christian; Schmitt, Andrea; Jordan, Wolfgang; Müller, Ulf J; Bernstein, Hans-Gert; Bogerts, Bernhard; Steiner, Johann

    2012-11-01

    Certain cytokines have been identified in the peripheral blood as trait markers of schizophrenia, while others are considered relapse-related state markers. Furthermore, data from peripheral blood, cerebrospinal fluid (CSF) and nuclear imaging studies suggest that (1) blood-brain barrier (BBB) dysfunction (e.g., immigration of lymphocytes into brain tissue and intrathecal antibody production) correlates with the development of negative symptoms, while (2) the brain's mononuclear phagocyte system (microglial cells) is activated during acute psychosis. Based on these neuroinflammatory hypotheses, we have quantified the numerical density of immunostained CD3+ T-lymphocytes, CD20+ B-lymphocytes, and HLA-DR+ microglial cells in the posterior hippocampus of 17 schizophrenia patients and 11 matched controls. Disease course-related immune alterations were considered by a separate analysis of residual (prevailing negative symptoms, n=7) and paranoid (prominent positive symptoms, n=10) schizophrenia cases. Higher densities of CD3+ and CD20+ lymphocytes were observed in residual versus paranoid schizophrenia (CD 3: left: P=0.047, right: P=0.038; CD20: left: P=0.020, right: P=0.010) and controls (CD3: left: P=0.057, right: P=0.069; CD20: left: P=0.008, right: P=0.006). In contrast, HLA-DR+ microglia were increased in paranoid schizophrenia versus residual schizophrenia (left: P=0.030, right: P=0.012). A similar trend emerged when this group was compared to controls (left: P=0.090, right: P=0.090). BBB impairment and infiltration of T cells and B cells may contribute to the pathophysiology of residual schizophrenia, while microglial activation seems to play a role in paranoid schizophrenia. The identification of diverse immune endophenotypes may facilitate the development of distinct anti-inflammatory schizophrenia therapies to normalize BBB function, (auto)antibody production or microglial activity. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Myelin-specific T cells induce interleukin-1beta expression in lesion-reactive microglial-like cells in zones of axonal degeneration

    DEFF Research Database (Denmark)

    Grebing, Manuela; Nielsen, Helle H; Fenger, Christina D

    2016-01-01

    lesion-reactive CD11b(+) ramified microglia. These results suggest that myelin-specific T cells stimulate lesion-reactive microglial-like cells to produce IL-1β. These findings are relevant to understand the consequences of T-cell infiltration in white and gray matter lesions in patients with MS. GLIA...

  7. Differential Response of Neural Cells to Trauma-Induced Swelling In Vitro.

    Science.gov (United States)

    Jayakumar, A R; Taherian, M; Panickar, K S; Shamaladevi, N; Rodriguez, M E; Price, B G; Norenberg, M D

    2018-02-01

    Brain edema and the associated increase in intracranial pressure are major consequences of traumatic brain injury (TBI) that accounts for most early deaths after TBI. We recently showed that acute severe trauma to cultured astrocytes results in cell swelling. We further examined whether trauma induces cell swelling in neurons and microglia. We found that severe trauma also caused cell swelling in cultured neurons, whereas no swelling was observed in microglia. While severe trauma caused cell swelling in both astrocytes and neurons, mild trauma to astrocytes, neurons, and microglia failed to cell swelling. Since extracellular levels of glutamate are increased in brain post-TBI and microglia are known to release cytokine, and direct exposure of astrocytes to these molecules are known to stimulate cell swelling, we examined whether glutamate or cytokines have any additive effect on trauma-induced cell swelling. Exposure of cultured astrocytes to trauma caused cell swelling, and such swelling was potentiated by the exposure of traumatized astrocytes to glutamate and cytokines. Conditioned medium (CM) from traumatized astrocytes had no effect on neuronal swelling post-trauma, while CM from traumatized neurons and microglia potentiated the effect of trauma on astrocyte swelling. Further, trauma significantly increased the Na-K-Cl co-transporter (NKCC) activity in neurons, and that inhibition of NKCC activity diminished the trauma-induced neuronal swelling. Our results indicate that a differential sensitivity to trauma-induced cell swelling exists in neural cells and that neurons and microglia are likely to be involved in the potentiation of the astrocyte swelling post-trauma.

  8. The temporal profile of the reaction of microglia, astrocytes, and macrophages in the delayed onset paraplegia after transient spinal cord ischemia in rabbits.

    Science.gov (United States)

    Matsumoto, Satoshi; Matsumoto, Mishiya; Yamashita, Atsuo; Ohtake, Kazunobu; Ishida, Kazuyoshi; Morimoto, Yasuhiro; Sakabe, Takefumi

    2003-06-01

    In the present study, we sought to elucidate the temporal profile of the reaction of microglia, astrocytes, and macrophages in the progression of delayed onset motor dysfunction after spinal cord ischemia (15 min) in rabbits. At 2, 4, 8, 12, 24, and 48 h after reperfusion (9 animals in each), hind limb motor function was assessed, and the lumbar spinal cord was histologically examined. Delayed motor dysfunction was observed in most animals at 48 h after ischemia, which could be predicted by a poor recovery of segmental spinal cord evoked potentials at 15 min of reperfusion. In the gray matter of the lumbar spinal cord, both microglia and astrocytes were activated early (2 h) after reperfusion. Microglia were diffusely activated and engulfed motor neurons irrespective of the recovery of segmental spinal cord evoked potentials. In contrast, early astrocytic activation was confined to the area where neurons started to show degeneration. Macrophages were first detected at 8 h after reperfusion and mainly surrounded the infarction area later. Although the precise roles of the activation of microglia, astrocytes, and macrophages are to be further determined, the results indicate that understanding functional changes of astrocytes may be important in the mechanism of delayed onset motor dysfunction including paraplegia. Microglia and macrophages play a role in removing tissue debris after transient spinal cord ischemia. Disturbance of astrocytic defense mechanism, breakdown of the blood-spinal cord barrier, or both seemed to be involved in the development of delayed motor dysfunction.

  9. The evaluation of role of NMDA receptor and spinal microglia on age dependent differences of neuropathic pain in SNL model in male rats

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    Hussain zeinali

    2015-04-01

    Full Text Available Background: Induced neuropathic pain following nerve injury has behavioral signs such as allodynia and hyperalgesia. There are reports about the age dependent differences in severity and incidence and even therapeutic response of this pain. In this study, we have tried to evaluate behavioral differences of this pain in an induced neuropathic model in different ages, according to important role of N-methyl, D-aspartate (NMDA receptor and spinal microglia on induction and maintenance of pain. Material and methods: Male rats were grouped in young (5-6 week and mature (10-11 week. Under general anesthesia, the spinal nerve ligation (SNL surgery was operated on right leg. The effect of different doses of dextromethorphan (NMDA blocker and minocycline (microglia inhibitor on 5th day after surgery was evaluated and compared in two age-groups. Results: In this study, both Minocycline and dextromethorphan diminished neuropathic pain in a dose dependent manner in these two ages. Minocycline in contrast to dextromethorphan was more effective in young rats. The co-administration of ineffective doses of minocycline and dextromethorphan could be effective. Conclusion: Microglia and NMDA receptor function in neuropathic pain is different in different ages and the role of microglia is more evident. On the other hand the inhibition of both microglia and NMDA receptor can be considered for lowering neuropathic pain.

  10. Reversible neural stem cell niche dysfunction in a model of multiple sclerosis

    DEFF Research Database (Denmark)

    Rasmussen, Stine; Imitola, Jaime; Ayuso-Sacido, Angel

    2011-01-01

    during EAE, we quantified the number of proliferating and differentiating progenitors, and evaluated the structure of the SVZ by electron microscopy. In vivo minocycline treatment during EAE was used to address the effect of microglia inactivation on SVZ dysfunction. RESULTS: In vivo treatment...... with minocycline, an inhibitor of microglia activation, increases stem cell proliferation in both naive and EAE animals. Minocycline treatment decreases cortical and periventricular pathology in the chronic phase of EAE, improving the proliferation of Sox2 stem cells and NG2 oligodendrocyte precursors cells...

  11. Formation of multinucleated giant cells and microglial degeneration in rats expressing a mutant Cu/Zn superoxide dismutase gene

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    Streit Wolfgang J

    2007-02-01

    Full Text Available Abstract Background Microglial neuroinflammation is thought to play a role in the pathogenesis of amyotrophic lateral sclerosis (ALS. The purpose of this study was to provide a histopathological evaluation of the microglial neuroinflammatory response in a rodent model of ALS, the SOD1G93A transgenic rat. Methods Multiple levels of the CNS from spinal cord to cerebral cortex were studied in SOD1G93A transgenic rats during three stages of natural disease progression, including presymptomatic, early symptomatic (onset, and late symptomatic (end stage, using immuno- and lectin histochemical markers for microglia, such as OX-42, OX-6, and Griffonia simplicifolia isolectin B4. Results Our studies revealed abnormal aggregates of microglia forming in the spinal cord as early as the presymptomatic stage. During the symptomatic stages there was prominent formation of multinucleated giant cells through fusion of microglial cells in the spinal cord, brainstem, and red nucleus of the midbrain. Other brain regions, including substantia nigra, cranial nerve nuclei, hippocampus and cortex showed normal appearing microglia. In animals during end stage disease at 4–5 months of age virtually all microglia in the spinal cord gray matter showed extensive fragmentation of their cytoplasm (cytorrhexis, indicative of widespread microglial degeneration. Few microglia exhibiting nuclear fragmentation (karyorrhexis indicative of apoptosis were identified at any stage. Conclusion The current findings demonstrate the occurrence of severe abnormalities in microglia, such as cell fusions and cytorrhexis, which may be the result of expression of mutant SOD1 in these cells. The microglial changes observed are different from those that accompany normal microglial activation, and they demonstrate that aberrant activation and degeneration of microglia is part of the pathogenesis of motor neuron disease.

  12. Agonists for G-protein-coupled receptor 84 (GPR84) alter cellular morphology and motility but do not induce pro-inflammatory responses in microglia

    OpenAIRE

    Wei, Li; Tokizane, Kyohei; Konishi, Hiroyuki; Yu, Hua-Rong; Kiyama, Hiroshi

    2017-01-01

    Background Several G-protein-coupled receptors (GPCRs) have been shown to be important signaling mediators between neurons and glia. In our previous screening for identification of nerve injury-associated GPCRs, G-protein-coupled receptor 84 (GPR84) mRNA showed the highest up-regulation by microglia after nerve injury. GPR84 is a pro-inflammatory receptor of macrophages in a neuropathic pain mouse model, yet its function in resident microglia in the central nervous system is poorly understood...

  13. Proliferation of differentiated glial cells in the brain stem

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    P.C. Barradas

    1998-02-01

    Full Text Available Classical studies of macroglial proliferation in muride rodents have provided conflicting evidence concerning the proliferating capabilities of oligodendrocytes and microglia. Furthermore, little information has been obtained in other mammalian orders and very little is known about glial cell proliferation and differentiation in the subclass Metatheria although valuable knowledge may be obtained from the protracted period of central nervous system maturation in these forms. Thus, we have studied the proliferative capacity of phenotypically identified brain stem oligodendrocytes by tritiated thymidine radioautography and have compared it with known features of oligodendroglial differentiation as well as with proliferation of microglia in the opossum Didelphis marsupialis. We have detected a previously undescribed ephemeral, regionally heterogeneous proliferation of oligodendrocytes expressing the actin-binding, ensheathment-related protein 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNPase, that is not necessarily related to the known regional and temporal heterogeneity of expression of CNPase in cell bodies. On the other hand, proliferation of microglia tagged by the binding of Griffonia simplicifolia B4 isolectin, which recognizes an alpha-D-galactosyl-bearing glycoprotein of the plasma membrane of macrophages/microglia, is known to be long lasting, showing no regional heterogeneity and being found amongst both ameboid and differentiated ramified cells, although at different rates. The functional significance of the proliferative behavior of these differentiated cells is unknown but may provide a low-grade cell renewal in the normal brain and may be augmented under pathological conditions.

  14. Deficiency of PTP1B Attenuates Hypothalamic Inflammation via Activation of the JAK2-STAT3 Pathway in Microglia.

    Science.gov (United States)

    Tsunekawa, Taku; Banno, Ryoichi; Mizoguchi, Akira; Sugiyama, Mariko; Tominaga, Takashi; Onoue, Takeshi; Hagiwara, Daisuke; Ito, Yoshihiro; Iwama, Shintaro; Goto, Motomitsu; Suga, Hidetaka; Sugimura, Yoshihisa; Arima, Hiroshi

    2017-02-01

    Protein tyrosine phosphatase 1B (PTP1B) regulates leptin signaling in hypothalamic neurons via the JAK2-STAT3 pathway. PTP1B has also been implicated in the regulation of inflammation in the periphery. However, the role of PTP1B in hypothalamic inflammation, which is induced by a high-fat diet (HFD), remains to be elucidated. Here, we showed that STAT3 phosphorylation (p-STAT3) was increased in microglia in the hypothalamic arcuate nucleus of PTP1B knock-out mice (KO) on a HFD, accompanied by decreased Tnf and increased Il10 mRNA expression in the hypothalamus compared to wild-type mice (WT). In hypothalamic organotypic cultures, incubation with TNFα led to increased p-STAT3, accompanied by decreased Tnf and increased Il10 mRNA expression, in KO compared to WT. Incubation with p-STAT3 inhibitors or microglial depletion eliminated the differences in inflammation between genotypes. These data indicate an important role of JAK2-STAT3 signaling negatively regulated by PTP1B in microglia, which attenuates hypothalamic inflammation under HFD conditions. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Deficiency of PTP1B Attenuates Hypothalamic Inflammation via Activation of the JAK2-STAT3 Pathway in Microglia

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    Taku Tsunekawa

    2017-02-01

    Full Text Available Protein tyrosine phosphatase 1B (PTP1B regulates leptin signaling in hypothalamic neurons via the JAK2-STAT3 pathway. PTP1B has also been implicated in the regulation of inflammation in the periphery. However, the role of PTP1B in hypothalamic inflammation, which is induced by a high-fat diet (HFD, remains to be elucidated. Here, we showed that STAT3 phosphorylation (p-STAT3 was increased in microglia in the hypothalamic arcuate nucleus of PTP1B knock-out mice (KO on a HFD, accompanied by decreased Tnf and increased Il10 mRNA expression in the hypothalamus compared to wild-type mice (WT. In hypothalamic organotypic cultures, incubation with TNFα led to increased p-STAT3, accompanied by decreased Tnf and increased Il10 mRNA expression, in KO compared to WT. Incubation with p-STAT3 inhibitors or microglial depletion eliminated the differences in inflammation between genotypes. These data indicate an important role of JAK2-STAT3 signaling negatively regulated by PTP1B in microglia, which attenuates hypothalamic inflammation under HFD conditions.

  16. Microglial cell dysregulation in Brain Aging and Neurodegeneration.

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    Rommy eVon Bernhardi

    2015-07-01

    Full Text Available Aging is the main risk factor for neurodegenerative diseases. In aging, microglia undergo phenotypic changes compatible with their activation. Glial activation can lead to neuroinflammation, which is increasingly accepted as part of the pathogenesis of neurodegenerative diseases, including Alzheimer’s disease (AD. We hypothesize that in aging, aberrant microglia activation leads to a deleterious environment and neurodegeneration. In aged mice, microglia exhibit an increased expression of cytokines and an exacerbated inflammatory response to pathological changes. Whereas LPS increases nitric oxide secretion in microglia from young mice, induction of reactive oxygen species (ROS predominates in older mice. Furthermore, there is accumulation of DNA oxidative damage in mitochondria of microglia during aging, and also an increased intracellular ROS production. Increased ROS activates the redox-sensitive nuclear factor kappa B, which promotes more neuroinflammation, and can be translated in functional deficits, such as cognitive impairment. Mitochondria-derived ROS and cathepsin B, are also necessary for the microglial cell production of interleukin-1β, a key inflammatory cytokine. Interestingly, whereas the regulatory cytokine TGFβ1 is also increased in the aged brain, neuroinflammation persists. Assessing this apparent contradiction, we have reported that TGFβ1 induction and activation of Smad3 signaling after inflammatory stimulation are reduced in adult mice. Other protective functions, such as phagocytosis, although observed in aged animals, become not inducible by inflammatory stimuli and TGFβ1. Here, we discuss data suggesting that mitochondrial and endolysosomal dysfunction could at least partially mediate age-associated microglial cell changes, and, together with the impairment of the TGFβ1-Smad3 pathway, could result in a reduction of protective activation and a facilitation of cytotoxic activation of microglia, resulting in the

  17. Increase in the density of resting microglia precedes neuritic plaque formation and microglial activation in a transgenic model of Alzheimer´s disease

    Czech Academy of Sciences Publication Activity Database

    Rodríguez Arellano, Jose Julio; Witton, J.; Olabarria, M.; Noristani, H. N.; Verkhratsky, Alexei

    2010-01-01

    Roč. 1, č. 1 (2010), e1-e6 ISSN 2041-4889 R&D Projects: GA ČR GA309/09/1696; GA ČR GA305/08/1384 Institutional research plan: CEZ:AV0Z50390703 Keywords : microglia * Alzheimer ´s disease * hippocampus Subject RIV: FH - Neurology

  18. Activated microglia mediate synapse loss and short-term memory deficits in a mouse model of transthyretin-related oculoleptomeningeal amyloidosis.

    Science.gov (United States)

    Azevedo, E P; Ledo, J H; Barbosa, G; Sobrinho, M; Diniz, L; Fonseca, A C C; Gomes, F; Romão, L; Lima, F R S; Palhano, F L; Ferreira, S T; Foguel, D

    2013-09-05

    Oculoleptomeningeal amyloidosis (OA) is a fatal and untreatable hereditary disease characterized by the accumulation of transthyretin (TTR) amyloid within the central nervous system. The mechanisms underlying the pathogenesis of OA, and in particular how amyloid triggers neuronal damage, are still unknown. Here, we show that amyloid fibrils formed by a mutant form of TTR, A25T, activate microglia, leading to the secretion of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and nitric oxide. Further, we found that A25T amyloid fibrils induce the activation of Akt, culminating in the translocation of NFκB to the nucleus of microglia. While A25T fibrils were not directly toxic to neurons, the exposure of neuronal cultures to media conditioned by fibril-activated microglia caused synapse loss that culminated in extensive neuronal death via apoptosis. Finally, intracerebroventricular (i.c.v.) injection of A25T fibrils caused microgliosis, increased brain TNF-α and IL-6 levels and cognitive deficits in mice, which could be prevented by minocycline treatment. These results indicate that A25T fibrils act as pro-inflammatory agents in OA, activating microglia and causing neuronal damage.

  19. Reciprocal signals between microglia and neurons regulate alpha-synuclein secretion by exophagy through a neuronal cJU-N-Nterminal kinase-signaling axis

    DEFF Research Database (Denmark)

    Christensen, Dan Ploug; Ejlerskov, Patrick; Rasmussen, Izabela

    2016-01-01

    implicate stress kinases of the JNK family in the regulation of exophagy and release of alpha-SNC following endogenous or exogenous stimulation. In a wider scope, our results imply that microglia not only inflict bystander damage to neurons in late phases of inflammatory brain disease but may also be active...

  20. Anti-Inflammatory Modulation of Microglia via CD163-Targeted Glucocorticoids Protects Dopaminergic Neurons in the 6-OHDA Parkinson's Disease Model

    DEFF Research Database (Denmark)

    Tentillier, Noemie; Etzerodt, Anders; Olesen, Mads N

    2016-01-01

    intravenous CD163-targeted liposomes with Dexa for 3 weeks exhibited better motor performance than the control groups and had minimal glucocorticoid-driven side effects. Furthermore, these animals showed better survival of dopaminergic neurons in substantia nigra and an increased number of microglia...

  1. Interleukin-1beta and tumor necrosis factor-alpha are expressed by different subsets of microglia and macrophages after ischemic stroke in mice

    DEFF Research Database (Denmark)

    Clausen, Bettina H; Lambertsen, Kate L; Babcock, Alicia A

    2008-01-01

    BACKGROUND: Interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) are expressed by microglia and infiltrating macrophages following ischemic stroke. Whereas IL-1beta is primarily neurotoxic in ischemic stroke, TNF-alpha may have neurotoxic and/or neuroprotective effects. We inv...

  2. Neuron-derived IgG protects dopaminergic neurons from insult by 6-OHDA and activates microglia through the FcγR I and TLR4 pathways.

    Science.gov (United States)

    Zhang, Jie; Niu, Na; Wang, Mingyu; McNutt, Michael A; Zhang, Donghong; Zhang, Baogang; Lu, Shijun; Liu, Yuqing; Liu, Zhihui

    2013-08-01

    Oxidative and immune attacks from the environment or microglia have been implicated in the loss of dopaminergic neurons of Parkinson's disease. The role of IgG which is an important immunologic molecule in the process of Parkinson's disease has been unclear. Evidence suggests that IgG can be produced by neurons in addition to its traditionally recognized source B lymphocytes, but its function in neurons is poorly understood. In this study, extensive expression of neuron-derived IgG was demonstrated in dopaminergic neurons of human and rat mesencephalon. With an in vitro Parkinson's disease model, we found that neuron-derived IgG can improve the survival and reduce apoptosis of dopaminergic neurons induced by 6-hydroxydopamine toxicity, and also depress the release of NO from microglia triggered by 6-hydroxydopamine. Expression of TNF-α and IL-10 in microglia was elevated to protective levels by neuron-derived IgG at a physiologic level via the FcγR I and TLR4 pathways and microglial activation could be attenuated by IgG blocking. All these data suggested that neuron-derived IgG may exert a self-protective function by activating microglia properly, and IgG may be involved in maintaining immunity homeostasis in the central nervous system and serve as an active factor under pathological conditions such as Parkinson's disease. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  3. Edaravone Attenuates the Proinflammatory Response in Amyloid-β-Treated Microglia by Inhibiting NLRP3 Inflammasome-Mediated IL-1β Secretion

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    Hong-Mei Wang

    2017-10-01

    Full Text Available Background/Aims: Microglial activation is an important pathological feature in the brains of patients with Alzheimer’s disease (AD, and amyloid-β (Aβ peptides play a crucial role in microglial activation. In addition, edaravone (EDA was recently shown to suppress oxidative stress and proinflammatory cytokine production in APPswePS1dE9 (APP/PS1 mice. However, the mechanism by which EDA inhibits the Aβ-induced proinflammatory response in microglia is poorly understood. Methods: The mitochondrial membrane potential (∆ψm was evaluated using JC-1 staining. Intracellular reactive oxygen species (ROS and mitochondrial ROS levels were detected using CM-H2DCFDA and MitoSOXTM Red, respectively. The levels of CD11b, NLRP3, pro-caspase-1 and manganese superoxide dismutase (SOD-2 were observed by western blotting, and the levels of interleukin-1beta (IL-1β in culture supernatants were quantified using an ELISA kit. Results: Aβ induced microglia activation and mitochondrial dysfunction. In addition, mitochondrial dysfunction was associated with ROS accumulation and activation of the NLRP3 inflammasome. Importantly, Aβ induced activation of the NLRP3 inflammasome, leading to caspase-1 activation and IL-1β release in microglia. Moreover, EDA obviously attenuated the depolarization of ∆ψm, reduced mitochondria-derived ROS production and increased SOD-2 activity, resulting in the suppression of NLRP3 inflammasome-mediated IL-1β secretion in Aβ-treated microglia. Conclusion: EDA is a mitochondria-targeted antioxidant and exhibits anti-inflammatory effects on Aβ-treated microglia.

  4. Neural progenitor cells but not astrocytes respond distally to thoracic spinal cord injury in rat models

    Directory of Open Access Journals (Sweden)

    Tara Nguyen

    2017-01-01

    Full Text Available Traumatic spinal cord injury (SCI is a detrimental condition that causes loss of sensory and motor function in an individual. Many complex secondary injury cascades occur after SCI and they offer great potential for therapeutic targeting. In this study, we investigated the response of endogenous neural progenitor cells, astrocytes, and microglia to a localized thoracic SCI throughout the neuroaxis. Twenty-five adult female Sprague-Dawley rats underwent mild-contusion thoracic SCI (n = 9, sham surgery (n = 8, or no surgery (n = 8. Spinal cord and brain tissues were fixed and cut at six regions of the neuroaxis. Immunohistochemistry showed increased reactivity of neural progenitor cell marker nestin in the central canal at all levels of the spinal cord. Increased reactivity of astrocyte-specific marker glial fibrillary acidic protein was found only at the lesion epicenter. The number of activated microglia was significantly increased at the lesion site, and activated microglia extended to the lumbar enlargement. Phagocytic microglia and macrophages were significantly increased only at the lesion site. There were no changes in nestin, glial fibrillary acidic protein, microglia and macrophage response in the third ventricle of rats subjected to mild-contusion thoracic SCI compared to the sham surgery or no surgery. These findings indicate that neural progenitor cells, astrocytes and microglia respond differently to a localized SCI, presumably due to differences in inflammatory signaling. These different cellular responses may have implications in the way that neural progenitor cells can be manipulated for neuroregeneration after SCI. This needs to be further investigated.

  5. Alkaloids from the leaves of Uncaria rhynchophylla and their inhibitory activity on NO production in lipopolysaccharide-activated microglia.

    Science.gov (United States)

    Yuan, Dan; Ma, Bin; Wu, Chunfu; Yang, Jingyu; Zhang, Lijia; Liu, Suiku; Wu, Lijun; Kano, Yoshihiro

    2008-07-01

    Two new isomeric alkaloids, 18,19-dehydrocorynoxinic acid B (1) and 18,19-dehydrocorynoxinic acid (2), were isolated from the CHCl3 extract of the leaves of Uncaria rhynchophylla, together with four known rhynchophylline-type alkaloids, corynoxeine (3), isocorynoxeine (4), rhynchophylline (5), and isorhynchophylline (6), and an indole alkaloid glucoside, vincoside lactam (7). The structures of compounds 1 and 2 were elucidated by spectroscopic methods including UV, IR, HREIMS, 1D and 2D NMR, and CD experiments. The activity assay showed that compounds 3-6, with a C-16 carboxylic ester group, and 7 exhibited inhibitory activity on lipopolysaccharide (LPS)-induced NO release in primary cultured rat cortical microglia (IC 50: 13.7-19.0 microM). However, only weak inhibitory activity was observed for compounds 1 and 2, with a C-16 carboxylic acid group (IC 50: >100 microM).

  6. Microglia Polarization, Gene-Environment Interactions and Wnt/β-Catenin Signaling: Emerging Roles of Glia-Neuron and Glia-Stem/Neuroprogenitor Crosstalk for Dopaminergic Neurorestoration in Aged Parkinsonian Brain

    Directory of Open Access Journals (Sweden)

    Francesca L'Episcopo

    2018-02-01

    Full Text Available Neuroinflammatory processes are recognized key contributory factors in Parkinson's disease (PD physiopathology. While the causes responsible for the progressive loss of midbrain dopaminergic (mDA neuronal cell bodies in the subtantia nigra pars compacta are poorly understood, aging, genetics, environmental toxicity, and particularly inflammation, represent prominent etiological factors in PD development. Especially, reactive astrocytes, microglial cells, and infiltrating monocyte-derived macrophages play dual beneficial/harmful effects, via a panel of pro- or anti-inflammatory cytokines, chemokines, neurotrophic and neurogenic transcription factors. Notably, with age, microglia may adopt a potent neurotoxic, pro-inflammatory “primed” (M1 phenotype when challenged with inflammatory or neurotoxic stimuli that hamper brain's own restorative potential and inhibit endogenous neurorepair mechanisms. In the last decade we have provided evidence for a major role of microglial crosstalk with astrocytes, mDA neurons and neural stem progenitor cells (NSCs in the MPTP- (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine- mouse model of PD, and identified Wnt/β-catenin signaling, a pivotal morphogen for mDA neurodevelopment, neuroprotection, and neuroinflammatory modulation, as a critical actor in glia-neuron and glia-NSCs crosstalk. With age however, Wnt signaling and glia-NSC-neuron crosstalk become dysfunctional with harmful consequences for mDA neuron plasticity and repair. These findings are of importance given the deregulation of Wnt signaling in PD and the emerging link between most PD related genes, Wnt signaling and inflammation. Especially, in light of the expanding field of microRNAs and inflammatory PD-related genes as modulators of microglial-proinflammatory status, uncovering the complex molecular circuitry linking PD and neuroinflammation will permit the identification of new druggable targets for the cure of the disease. Here we summarize

  7. Effectors of Th1 and Th17 cells act on astrocytes and augment their neuroinflammatory properties.

    Science.gov (United States)

    Prajeeth, Chittappen K; Kronisch, Julius; Khorooshi, Reza; Knier, Benjamin; Toft-Hansen, Henrik; Gudi, Viktoria; Floess, Stefan; Huehn, Jochen; Owens, Trevor; Korn, Thomas; Stangel, Martin

    2017-10-16

    Autoreactive Th1 and Th17 cells are believed to mediate the pathology of multiple sclerosis in the central nervous system (CNS). Their interaction with microglia and astrocytes in the CNS is crucial for the regulation of the neuroinflammation. Previously, we have shown that only Th1 but not Th17 effectors activate microglia. However, it is not clear which cells are targets of Th17 effectors in the CNS. To understand the effects driven by Th17 cells in the CNS, we induced experimental autoimmune encephalomyelitis in wild-type mice and CD4 + T cell-specific integrin α4-deficient mice where trafficking of Th1 cells into the CNS was affected. We compared microglial and astrocyte response in the brain and spinal cord of these mice. We further treated astrocytes with supernatants from highly pure Th1 and Th17 cultures and assessed the messenger RNA expression of neurotrophic factors, cytokines and chemokines, using real-time PCR. Data obtained was analyzed using the Kruskal-Wallis test. We observed in α4-deficient mice weak microglial activation but comparable astrogliosis to that of wild-type mice in the regions of the brain populated with Th17 infiltrates, suggesting that Th17 cells target astrocytes and not microglia. In vitro, in response to supernatants from Th1 and Th17 cultures, astrocytes showed altered expression of neurotrophic factors, pro-inflammatory cytokines and chemokines. Furthermore, increased expression of chemokines in Th1- and Th17-treated astrocytes enhanced recruitment of microglia and transendothelial migration of Th17 cells in vitro. Our results demonstrate the delicate interaction between T cell subsets and glial cells and how they communicate to mediate their effects. Effectors of Th1 act on both microglia and astrocytes whereas Th17 effectors preferentially target astrocytes to promote neuroinflammation.

  8. Glia and immune cell signaling in bipolar disorder: insights from neuropharmacology and molecular imaging to clinical application.

    Science.gov (United States)

    Watkins, C C; Sawa, A; Pomper, M G

    2014-01-21

    Bipolar disorder (BD) is a debilitating mental illness characterized by severe fluctuations in mood, sleep, energy and executive functioning. Pharmacological studies of selective serotonin reuptake inhibitors and the monoamine system have helped us to clinically understand bipolar depression. Mood stabilizers such as lithium and valproic acid, the first-line treatments for bipolar mania and depression, inhibit glycogen synthase kinase-3 beta (GSK-3β) and regulate the Wnt pathway. Recent investigations suggest that microglia, the resident immune cells of the brain, provide a physiological link between the serotonin system and the GSK-3β/Wnt pathway through neuroinflammation. We review the pharmacological, translational and brain imaging studies that support a role for microglia in regulating neurotransmitter synthesis and immune cell activation. These investigations provide a model for microglia involvement in the pathophysiology and phenotype of BD that may translate into improved therapies.

  9. Thrombin-induced, TNFR-dependent miR-181c downregulation promotes MLL1 and NF-κB target gene expression in human microglia.

    Science.gov (United States)

    Yin, Min; Chen, Zhiying; Ouyang, Yetong; Zhang, Huiyan; Wan, Zhigang; Wang, Han; Wu, Wei; Yin, Xiaoping

    2017-06-29

    Controlling thrombin-driven microglial activation may serve as a therapeutic target for intracerebral hemorrhage (ICH). Here, we investigated microRNA (miRNA)-based regulation of thrombin-driven microglial activation using an in vitro thrombin toxicity model applied to primary human microglia. A miRNA array identified 22 differential miRNA candidates. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) identified miR-181c as the most significantly downregulated miRNA. TargetScan analysis identified mixed lineage leukemia-1 (MLL1) as a putative gene target for miR-181c. qRT-PCR was applied to assess tumor necrosis factor-alpha (TNF-α), miR-181c, and MLL1 levels following thrombin or proteinase-activated receptor-4-specific activating peptide (PAR4AP) exposure. Anti-TNF-α antibodies and tumor necrosis factor receptor (TNFR) silencing were employed to test TNF-α/TNFR dependence. A dual-luciferase reporter system and miR-181c mimic transfection assessed whether mir-181c directly binds to and negatively regulates MLL1. Nuclear factor kappa-B (NF-κB)-dependent luciferase reporter assays and NF-κB target gene expression were assessed in wild-type (MLL1+) and MLL1-silenced cells. Thrombin or PAR4AP-induced miR-181c downregulation (p < 0.05) and MLL1 upregulation (p < 0.05) that were dependent upon TNF-α/TNFR. miR-181c decreased wild-type MLL1 3'-UTR luciferase reporter activity (p < 0.05), and a miR-181c mimic suppressed MLL1 expression (p < 0.05). Thrombin treatment increased, while miR-181c reduced, NF-κB activity and NF-κB target gene expression in both wild-type (MLL1+) and MLL1-silenced cells (p < 0.05). Thrombin-induced, TNF-α/TNFR-dependent miR-181c downregulation promotes MLL1 expression, increases NF-κB activity, and upregulates NF-κB target gene expression. As miR-181c opposes thrombin's stimulation of pro-inflammatory NF-κB activity, miR-181c mimic therapy may show promise in controlling thrombin

  10. Immunomodulation-accelerated neuronal regeneration following selective rod photoreceptor cell ablation in the zebrafish retina.

    Science.gov (United States)

    White, David T; Sengupta, Sumitra; Saxena, Meera T; Xu, Qingguo; Hanes, Justin; Ding, Ding; Ji, Hongkai; Mumm, Jeff S

    2017-05-02

    Müller glia (MG) function as inducible retinal stem cells in zebrafish, completely repairing the eye after damage. The innate immune system has recently been shown to promote tissue regeneration in which classic wound-healing responses predominate. However, regulatory roles for leukocytes during cellular regeneration-i.e., selective cell-loss paradigms akin to degenerative disease-are less well defined. To investigate possible roles innate immune cells play during retinal cell regeneration, we used intravital microscopy to visualize neutrophil, macrophage, and retinal microglia responses to induced rod photoreceptor apoptosis. Neutrophils displayed no reactivity to rod cell loss. Peripheral macrophage cells responded to rod cell loss, as evidenced by morphological transitions and increased migration, but did not enter the retina. Retinal microglia displayed multiple hallmarks of immune cell activation: increased migration, translocation to the photoreceptor cell layer, proliferation, and phagocytosis of dying cells. To test function during rod cell regeneration, we coablated microglia and rod cells or applied immune suppression and quantified the kinetics of ( i ) rod cell clearance, ( ii ) MG/progenitor cell proliferation, and ( iii ) rod cell replacement. Coablation and immune suppressants applied before cell loss caused delays in MG/progenitor proliferation rates and slowed the rate of rod cell replacement. Conversely, immune suppressants applied after cell loss had been initiated led to accelerated photoreceptor regeneration kinetics, possibly by promoting rapid resolution of an acute immune response. Our findings suggest that microglia control MG responsiveness to photoreceptor loss and support the development of immune-targeted therapeutic strategies for reversing cell loss associated with degenerative retinal conditions.

  11. Lentiviral-mediated administration of IL-25 in the CNS induces alternative activation of microglia

    DEFF Research Database (Denmark)

    Maiorino, C; Khorooshi, R; Ruffini, F

    2013-01-01

    Interleukin-25 (IL-25) is the only anti-inflammatory cytokine of the IL-17 family, and it has been shown to be efficacious in inhibiting neuroinflammation. Known for its effects on cells of the adaptive immune system, it has been more recently described to be effective also on cells of the innate...... was partly inhibited and the CNS protected from immune-mediated damage. To our knowledge, this is the first example of M2 shift (alternative activation) induced in vivo on CNS-resident myeloid cells by gene therapy, and may constitute a promising strategy to investigate the potential role of protective...

  12. Altered cerebellar development in nuclear receptor TAK1/ TR4 null mice is associated with deficits in GLAST(+) glia, alterations in social behavior, motor learning, startle reactivity, and microglia.

    Science.gov (United States)

    Kim, Yong-Sik; Harry, G Jean; Kang, Hong Soon; Goulding, David; Wine, Rob N; Kissling, Grace E; Liao, Grace; Jetten, Anton M

    2010-09-01

    Previously, deficiency in the expression of the nuclear orphan receptor TAK1 was found to be associated with delayed cerebellar granule cell migration and Purkinje cell maturation with a permanent deficit in foliation of lobules VI–VII, suggesting a role for TAK1 in cerebellum development. In this study, we confirm that TAK1-deficient (TAK1(−/−)) mice have a smaller cerebellum and exhibit a disruption of lobules VI–VII. We extended these studies and show that at postnatal day 7, TAK1(−/−) mice exhibit a delay in monolayer maturation of dysmorphic calbindin 28K-positive Purkinje cells. The astrocyte-specific glutamate transporter (GLAST) was expressed within Bergmann fibers and internal granule cell layer at significantly lower levels in the cerebellum of TAK1(−/−) mice. At PND21, Golgi-positive Purkinje cells in TAK1(−/−) mice displayed a smaller soma (18%) and shorter distance to first branch point (35%). Neuronal death was not observed in TAK1(−/−) mice at PND21; however, activated microglia were present in the cerebellum, suggestive of earlier cell death. These structural deficits in the cerebellum were not sufficient to alter motor strength, coordination, or activity levels; however, deficits in acoustic startle response, prepulse startle inhibition, and social interactions were observed. Reactions to a novel environment were inhibited in a light/dark chamber, open-field, and home-cage running wheel. TAK1(−/−) mice displayed a plateau in performance on the running wheel, suggesting a deficit in learning to coordinate performance on a motor task. These data indicate that TAK1 is an important transcriptional modulator of cerebellar development and neurodevelopmentally regulated behavior.

  13. Progranulin Is a Chemoattractant for Microglia and Stimulates Their Endocytic Activity

    OpenAIRE

    Pickford, Fiona; Marcus, Jacob; Camargo, Luiz Miguel; Xiao, Qiurong; Graham, Danielle; Mo, Jan-Rung; Burkhardt, Matthew; Kulkarni, Vinayak; Crispino, Jamie; Hering, Heike; Hutton, Michael

    2011-01-01

    Mutations resulting in progranulin haploinsufficiency cause disease in patients with a subset of frontotemporal lobar degeneration; however, the biological functions of progranulin in the brain remain unknown. To address this subject, the present study initially assessed changes in gene expression and cytokine secretion in rat primary cortical neurons treated with progranulin. Molecular pathways enriched in the progranulin gene set included cell adhesion and cell motility pathways and pathway...

  14. Gc-protein-derived macrophage activating factor counteracts the neuronal damage induced by oxaliplatin.

    Science.gov (United States)

    Morucci, Gabriele; Branca, Jacopo J V; Gulisano, Massimo; Ruggiero, Marco; Paternostro, Ferdinando; Pacini, Alessandra; Di Cesare Mannelli, Lorenzo; Pacini, Stefania

    2015-02-01

    Oxaliplatin-based regimens are effective in metastasized advanced cancers. However, a major limitation to their widespread use is represented by neurotoxicity that leads to peripheral neuropathy. In this study we evaluated the roles of a proven immunotherapeutic agent [Gc-protein-derived macrophage activating factor (GcMAF)] in preventing or decreasing oxaliplatin-induced neuronal damage and in modulating microglia activation following oxaliplatin-induced damage. The effects of oxaliplatin and of a commercially available formula of GcMAF [oleic acid-GcMAF (OA-GcMAF)] were studied in human neurons (SH-SY5Y cells) and in human microglial cells (C13NJ). Cell density, morphology and viability, as well as production of cAMP and expression of vascular endothelial growth factor (VEGF), markers of neuron regeneration [neuromodulin or growth associated protein-43 (Gap-43)] and markers of microglia activation [ionized calcium binding adaptor molecule 1 (Iba1) and B7-2], were determined. OA-GcMAF reverted the damage inflicted by oxaliplatin on human neurons and preserved their viability. The neuroprotective effect was accompanied by increased intracellular cAMP production, as well as by increased expression of VEGF and neuromodulin. OA-GcMAF did not revert the effects of oxaliplatin on microglial cell viability. However, it increased microglial activation following oxaliplatin-induced damage, resulting in an increased expression of the markers Iba1 and B7-2 without any concomitant increase in cell number. When neurons and microglial cells were co-cultured, the presence of OA-GcMAF significantly counteracted the toxic effects of oxaliplatin. Our results demonstrate that OA-GcMAF, already used in the immunotherapy of advanced cancers, may significantly contribute to neutralizing the neurotoxicity induced by oxaliplatin, at the same time possibly concurring to an integrated anticancer effect. The association between these two powerful anticancer molecules would probably produce

  15. Quantification of the functional expression of the Ca(2+) -activated K(+) channel KCa 3.1 on microglia from adult human neocortical tissue

    DEFF Research Database (Denmark)

    Blomster, Linda V; Strøbaek, Dorte; Hougaard, Charlotte

    2016-01-01

    by full inhibition upon co-application with NS6180, a highly selective KCa 3.1 inhibitor. A major fraction (79%) of unstimulated human microglia expressed KCa 3.1, and the difference in current between full activation and inhibition (ΔKCa 3.1) was estimated at 292 ± 48 pA at -40 mV (n = 75), which equals...... in neuropathological processes. GLIA 2016;64:2065-2078....

  16. Electroacupunctre improves motor impairment via inhibition of microglia-mediated neuroinflammation in the sensorimotor cortex after ischemic stroke.

    Science.gov (United States)

    Liu, Weilin; Wang, Xian; Yang, Shanli; Huang, Jia; Xue, Xiehua; Zheng, Yi; Shang, Guanhao; Tao, Jing; Chen, Lidian

    2016-04-15

    Electroacupuncture (EA) is one of the safety and effective therapies for improving neurological and sensorimotor impairment via blockade of inappropriate inflammatory responses. However, the mechanisms of anti-inflammation involved is far from been fully elucidated. Focal cerebral ischemic stroke was administered by the middle cerebral artery occlusion and reperfusion (MCAO/R) surgery. The MCAO/R rats were accepted EA treatment at the LI 11 and ST 36 acupoints for consecutive 3days. The neurological outcome, animal behaviors test and molecular biology assays were used to evaluate the MCAO/R model and therapeutic effect of EA. EA treatment for MCAO rats showed a significant reduction in the infarct volumes accompanied by functional recovery in mNSS outcomes, motor function performances. The possible mechanisms that EA treatment attenuated the over-activation of Iba-1 and ED1 positive microglia in the peri-infract sensorimotor cortex. Simultaneously, both tissue and serum protein levels of the tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were decreased by EA treatment in MCAO/R injured rats. The levels of inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) were decreased in the peri-infract sensorimotor cortex and blood serum of MCAO/R injured rats after EA treatment. Furthermore, we found that EA treatment prevented from the nucleus translocation of NF-κB p65 and suppressed the expression of p38 mitogen-activated protein kinase (p38 MAPK) and myeloid differentiation factor 88 (MyD88) in the peri-infract sensorimotor cortex. The findings from this study indicated that EA improved the motor impairment via inhibition of microglia-mediated neuroinflammation that invoked NF-κB p65, p38 MAPK and MyD88 produced proinflammatory cytokine in the peri-infract sensorimotor cortex of rats following ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Early Postoperative Nociceptive Threshold and Production of Brain-Derived Neurotrophic Factor Induced by Plantar Incision Are Not Influenced with Minocycline in a Rat: Role of Spinal Microglia

    Directory of Open Access Journals (Sweden)

    Eiji Masaki

    2016-03-01

    Full Text Available Background: Brain-derived neurotrophic factor (BDNF from spinal microglia is crucial for aberrant nociceptive signaling in several pathological pain conditions, including postoperative pain. We assess the contribution of spinal microglial activation and associated BDNF overexpression to the early post-incisional nociceptive threshold. Methods: Male Sprague-Dawley rats were implanted with an intrathecal catheter. A postoperative pain model was established by plantar incision. Thermal and mechanical nociceptive responses were assessed by infrared radiant heat and von Frey filaments before and after plantar incision. Rats were injected intrathecally the microglial activation inhibitor minocycline before incision, 24 h after incision, or both. Other groups were subjected to the same treatments and the L4-L5 spinal cord segment removed for immunohistochemical analysis of microglia activation and BNDF expression. Results: Plantar incision reduced both thermal latency and mechanical threshold, indicating thermal hypersensitivity and mechanical allodynia. Minocycline temporally reduced thermal withdrawal latency but had no effect on mechanical withdrawal threshold, spinal microglial activity, or dorsal horn BDNF overexpression during the early post-incision period. Conclusion: These results suggest that spinal microglia does not contribute substantially to post-incisional nociceptive threshold. The BDNF overexpression response that may contribute to postoperative hyperalgesia and allodynia is likely derived from other sources.

  18. Next generation transcriptomics and genomics elucidate biological complexity of microglia in health and disease

    NARCIS (Netherlands)

    Wes, Paul D; Holtman, Inge R; Boddeke, Erik W G M; Möller, Thomas; Eggen, Bart J L

    2015-01-01

    Genome-wide expression profiling technology has resulted in detailed transcriptome data for a wide range of tissues, conditions and diseases. In neuroscience, expression datasets were mostly generated using whole brain tissue samples, resulting in data from a mixture of cell types, including glial

  19. Astrocyte Hypertrophy and Microglia Activation in the Rat Auditory Midbrain Is Induced by Electrical Intracochlear Stimulation.

    Science.gov (United States)

    Rosskothen-Kuhl, Nicole; Hildebrandt, Heika; Birkenhäger, Ralf; Illing, Robert-Benjamin

    2018-01-01

    Neuron-glia interactions contribute to tissue homeostasis and functional plasticity in the mammalian brain, but it remains unclear how this is achieved. The potential of central auditory brain tissue for stimulation-dependent cellular remodeling was studied in hearing-experienced and neonatally deafened rats. At adulthood, both groups received an intracochlear electrode into the left cochlea and were continuously stimulated for 1 or 7 days after waking up from anesthesia. Normal hearing and deafness were assessed by auditory brainstem responses (ABRs). The effectiveness of stimulation was verified by electrically evoked ABRs as well as immunocytochemistry and in situ hybridization for the immediate early gene product Fos on sections through the auditory midbrain containing the inferior colliculus (IC). Whereas hearing-experienced animals showed a tonotopically restricted Fos response in the IC contralateral to electrical intracochlear stimulation, Fos-positive neurons were found almost throughout the contralateral IC in deaf animals. In deaf rats, the Fos response was accompanied by a massive increase of GFAP indicating astrocytic hypertrophy, and a local activation of microglial cells identified by IBA1. These glia responses led to a noticeable increase of neuron-glia approximations. Moreover, staining for the GABA synthetizing enzymes GAD65 and GAD67 rose significantly in neuronal cell bodies and presynaptic boutons in the contralateral IC of deaf rats. Activation of neurons and glial cells and tissue re-composition were in no case accompanied by cell death as would have been apparent by a Tunel reaction. These findings suggest that growth and activity of glial cells is crucial for the local adjustment of neuronal inhibition to neuronal excitation.

  20. COL-3, a chemically modified tetracycline, inhibits lipopolysaccharide-induced microglia activation and cytokine expression in the brain.

    Directory of Open Access Journals (Sweden)

    Rawan Abdulhameed Edan

    Full Text Available Microglia activation results in release of proinflammatory molecules including cytokines, which contribute to neuronal damage in the central nervous system (CNS if not controlled. Tetracycline antibiotics such as minocycline inhibit microglial activation and cytokine expression during CNS inflammation. In the present study we found that administration of chemically modified tetracycline-3 (COL-3, inhibits lipopolysaccharide (LPS-induced microglial and p38 MAPK activation, as well as the increase in TNF-α, but not IL-1β expression, in the brains of BALB/c mice. COL-3 has been described to have no antibacterial activity. We observed that COL-3 had no activity against a Gram-negative bacteria, Escherichia coli; however surprisingly, COL-3 had antibacterial activity against a Gram-positive bacteria Staphylococcus aureus, with a minimum inhibitory concentration of 1 mg/ml. Our data show that COL-3 has some antibacterial activity against S. aureus, inhibits LPS-induced neuroinflammation, and displays potential as a therapeutic agent for treatment of conditions involving CNS inflammation.

  1. Cognitive deficits develop 1month after diffuse brain injury and are exaggerated by microglia-associated reactivity to peripheral immune challenge.

    Science.gov (United States)

    Muccigrosso, Megan M; Ford, Joni; Benner, Brooke; Moussa, Daniel; Burnsides, Christopher; Fenn, Ashley M; Popovich, Phillip G; Lifshitz, Jonathan; Walker, Fredrick Rohan; Eiferman, Daniel S; Godbout, Jonathan P

    2016-05-01

    Traumatic brain injury (TBI) elicits immediate neuroinflammatory events that contribute to acute cognitive, motor, and affective disturbance. Despite resolution of these acute complications, significant neuropsychiatric and cognitive issues can develop and progress after TBI. We and others have provided novel evidence that these complications are potentiated by repeated injuries, immune challenges and stressors. A key component to this may be increased sensitization or priming of glia after TBI. Therefore, our objectives were to determine the degree to which cognitive deterioration occurred after diffuse TBI (moderate midline fluid percussion injury) and ascertain if glial reactivity induced by an acute immune challenge potentiated cognitive decline 30 days post injury (dpi). In post-recovery assessments, hippocampal-dependent learning and memory recall were normal 7 dpi, but anterograde learning was impaired by 30 dpi. Examination of mRNA and morphological profiles of glia 30 dpi indicated a low but persistent level of inflammation with elevated expression of GFAP and IL-1β in astrocytes and MHCII and IL-1β in microglia. Moreover, an acute immune challenge 30 dpi robustly interrupted memory consolidation specifically in TBI mice. These deficits were associated with exaggerated microglia-mediated inflammation with amplified (IL-1β, CCL2, TNFα) and prolonged (TNFα) cytokine/chemokine expression, and a marked reactive morphological profile of microglia in the CA3 of the hippocampus. Collectively, these data indicate that microglia remain sensitized 30 dpi after moderate TBI and a secondary inflammatory challenge elicits robust microglial reactivity that augments cognitive decline. Traumatic brain injury (TBI) is a major risk factor in development of neuropsychiatric problems long after injury, negatively affecting quality of life. Mounting evidence indicates that inflammatory processes worsen with time after a brain injury and are likely mediated by glia. Here

  2. Extracellular histone H1 is neurotoxic and drives a pro-inflammatory response in microglia [v1; ref status: indexed, http://f1000r.es/18z

    Directory of Open Access Journals (Sweden)

    Jonathan D Gilthorpe

    2013-07-01

    Full Text Available In neurodegenerative conditions and following brain trauma it is not understood why neurons die while astrocytes and microglia survive and adopt pro-inflammatory phenotypes. We show here that the damaged adult brain releases diffusible factors that can kill cortical neurons and we have identified histone H1 as a major extracellular candidate that causes neurotoxicity and activation of the innate immune system. Extracellular core histones H2A, H2B H3 and H4 were not neurotoxic. Innate immunity in the central nervous system is mediated through microglial cells and we show here for the first time that histone H1 promotes their survival, up-regulates MHC class II antigen expression and is a powerful microglial chemoattractant. We propose that when the central nervous system is degenerating, histone H1 drives a positive feedback loop that drives further degeneration and activation of immune defences which can themselves be damaging. We suggest that histone H1 acts as an antimicrobial peptide and kills neurons through mitochondrial damage and apoptosis.

  3. From development to dysfunction: Microglia and the complement cascade in CNS homeostasis

    OpenAIRE

    Zabel, Matthew K.; Kirsch, Wolff M.

    2013-01-01

    Of the many mysteries that surround the brain, few surpass the awe-inspiring complexity of its development. The intricate wiring of the brain at both the system and molecular level is both spatially and temporally regulated in perfect synchrony. How such a delicate, yet elegant, system arises from an embryo’s most basic cells remains at the forefront of neuroscientific research. At the cellular level, the competitive dance between synapses struggling to gain dominance seems to be refereed by ...

  4. Salidroside Reduces Cell Mobility via NF-κB and MAPK Signaling in LPS-Induced BV2 Microglial Cells

    Directory of Open Access Journals (Sweden)

    Haixia Hu

    2014-01-01

    Full Text Available The unregulated activation of microglia following stroke results in the production of toxic factors that propagate secondary neuronal injury. Salidroside has been shown to exhibit protective effects against neuronal death induced by different insults. However, the molecular mechanisms responsible for the anti-inflammatory activity of salidroside have not been elucidated clearly in microglia. In the present study, we investigated the molecular mechanism underlying inhibiting LPS-stimulated BV2 microglial cell mobility of salidroside. The protective effect of salidroside was investigated in microglial BV2 cell, subjected to stretch injury. Moreover, transwell migration assay demonstrated that salidroside significantly reduced cell motility. Our results also indicated that salidroside suppressed LPS-induced chemokines production in a dose-dependent manner, without causing cytotoxicity in BV2 microglial cells. Moreover, salidroside suppressed LPS-induced activation of nuclear factor kappa B (NF-κB by blocking degradation of IκBα and phosphorylation of MAPK (p38, JNK, ERK1/2, which resulted in inhibition of chemokine expression. These results suggest that salidroside possesses a potent suppressive effect on cell migration of BV2 microglia and this compound may offer substantial therapeutic potential for treatment of ischemic strokes that are accompanied by microglial activation.

  5. Voluntary Exercise Promotes Glymphatic Clearance of Amyloid Beta and Reduces the Activation of Astrocytes and Microglia in Aged Mice.

    Science.gov (United States)

    He, Xiao-Fei; Liu, Dong-Xu; Zhang, Qun; Liang, Feng-Ying; Dai, Guang-Yan; Zeng, Jin-Sheng; Pei, Zhong; Xu, Guang-Qing; Lan, Yue

    2017-01-01

    Age is characterized by chronic inflammation, leading to synaptic dysfunction and dementia because the clearance of protein waste is reduced. The clearance of proteins depends partly on the permeation of the blood-brain barrier (BBB) or on the exchange of water and soluble contents between the cerebrospinal fluid (CSF) and the interstitial fluid (ISF). A wealth of evidence indicates that physical exercise improves memory and cognition in neurodegenerative diseases during aging, such as Alzheimer's disease (AD), but the influence of physical training on glymphatic clearance, BBB permeability and neuroinflammation remains unclear. In this study, glymphatic clearance and BBB permeability were evaluated in aged mice using in vivo two-photon imaging. The mice performed voluntary wheel running exercise and their water-maze cognition was assessed; the expression of the astrocytic water channel aquaporin 4 (AQP4), astrocyte and microglial activation, and the accumulation of amyloid beta (Aβ) were evaluated with immunofluorescence or an enzyme-linked immunosorbent assay (ELISA); synaptic function was investigated with Thy1 -green fluorescent protein (GFP) transgenic mice and immunofluorescent staining. Voluntary wheel running significantly improved water-maze cognition in the aged mice, accelerated the efficiency of glymphatic clearance, but which did not affect BBB permeability. The numbers of activated astrocytes and microglia decreased, AQP4 expression increased, and the distribution of astrocytic AQP4 was rearranged. Aβ accumulation decreased, whereas dendrites, dendritic spines and postsynaptic density protein (PSD95) increased. Our study suggests that voluntary wheel running accelerated glymphatic clearance but not BBB permeation, improved astrocytic AQP4 expression and polarization, attenuated the accumulation of amyloid plaques and neuroinflammation, and ultimately protected mice against synaptic dysfunction and a decline in spatial cognition. These data suggest

  6. Voluntary Exercise Promotes Glymphatic Clearance of Amyloid Beta and Reduces the Activation of Astrocytes and Microglia in Aged Mice

    Directory of Open Access Journals (Sweden)

    Xiao-fei He

    2017-05-01

    Full Text Available Age is characterized by chronic inflammation, leading to synaptic dysfunction and dementia because the clearance of protein waste is reduced. The clearance of proteins depends partly on the permeation of the blood–brain barrier (BBB or on the exchange of water and soluble contents between the cerebrospinal fluid (CSF and the interstitial fluid (ISF. A wealth of evidence indicates that physical exercise improves memory and cognition in neurodegenerative diseases during aging, such as Alzheimer’s disease (AD, but the influence of physical training on glymphatic clearance, BBB permeability and neuroinflammation remains unclear. In this study, glymphatic clearance and BBB permeability were evaluated in aged mice using in vivo two-photon imaging. The mice performed voluntary wheel running exercise and their water-maze cognition was assessed; the expression of the astrocytic water channel aquaporin 4 (AQP4, astrocyte and microglial activation, and the accumulation of amyloid beta (Aβ were evaluated with immunofluorescence or an enzyme-linked immunosorbent assay (ELISA; synaptic function was investigated with Thy1–green fluorescent protein (GFP transgenic mice and immunofluorescent staining. Voluntary wheel running significantly improved water-maze cognition in the aged mice, accelerated the efficiency of glymphatic clearance, but which did not affect BBB permeability. The numbers of activated astrocytes and microglia decreased, AQP4 expression increased, and the distribution of astrocytic AQP4 was rearranged. Aβ accumulation decreased, whereas dendrites, dendritic spines and postsynaptic density protein (PSD95 increased. Our study suggests that voluntary wheel running accelerated glymphatic clearance but not BBB permeation, improved astrocytic AQP4 expression and polarization, attenuated the accumulation of amyloid plaques and neuroinflammation, and ultimately protected mice against synaptic dysfunction and a decline in spatial cognition

  7. Acetate supplementation reduces microglia activation and brain interleukin-1β levels in a rat model of Lyme neuroborreliosis

    Directory of Open Access Journals (Sweden)

    Brissette Catherine A

    2012-11-01

    Full Text Available Abstract Background We have found that acetate supplementation significantly reduces neuroglia activation and pro-inflammatory cytokine release in a rat model of neuroinflammation induced with lipopolysaccharide. To test if the anti-inflammatory effect of acetate supplementation is specific to a TLR4-mediated injury, we measured markers of neuroglia activation in rats subjected to B. burgdorferi-induced neuroborreliosis that is mediated in large part by a TLR2-type mechanism. Methods In this study, rats were subjected to Lyme neuroborreliosis following an intravenous infusion of B. burgdorferi (B31-MI-16. Acetate supplementation was induced using glyceryl triacetate (6g/kg by oral gavage. Immunohistochemistry, qPCR, and western blot analyses were used to measure bacterial invasion into the brain, neuroglial activation, and brain and circulating levels of interleukin 1β. Statistical analysis was performed using one-way analysis of variance (ANOVA followed by a Tukey’s post hoc tests or using a Student’s t test assuming unequal variances when appropriate. Results We found that acetate supplementation