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Sample records for activated microglia play

  1. Factors regulating microglia activation

    PubMed Central

    Kierdorf, Katrin; Prinz, Marco

    2013-01-01

    Microglia are resident macrophages of the central nervous system (CNS) that display high functional similarities to other tissue macrophages. However, it is especially important to create and maintain an intact tissue homeostasis to support the neuronal cells, which are very sensitive even to minor changes in their environment. The transition from the “resting” but surveying microglial phenotype to an activated stage is tightly regulated by several intrinsic (e.g., Runx-1, Irf8, and Pu.1) and extrinsic factors (e.g., CD200, CX3CR1, and TREM2). Under physiological conditions, minor changes of those factors are sufficient to cause fatal dysregulation of microglial cell homeostasis and result in severe CNS pathologies. In this review, we discuss recent achievements that gave new insights into mechanisms that ensure microglia quiescence. PMID:23630462

  2. PI3k/Akt signalling pathway plays a crucial role in the anti-inflammatory effects of curcumin in LPS-activated microglia.

    PubMed

    Cianciulli, Antonia; Calvello, Rosa; Porro, Chiara; Trotta, Teresa; Salvatore, Rosaria; Panaro, Maria Antonietta

    2016-07-01

    Microglia are resident macrophages in the central nervous system (CNS) deputed to defend against pathogens. Persistent or acute inflammation of microglia leads to CNS disorders, so regulation of pro-inflammatory responses of microglial cells is thought to be a promising therapeutic strategy to attenuate abnormal inflammatory responses observed in neurodegenerative disease. We hypothesized that curcumin supplementation could reduce the inflammatory responses of activated microglial cells modulating PI3K/Akt pathway. Different curcumin concentrations were administered as BV-2 microglia pre-treatment 1h prior to LPS stimulation. Nitric oxide (NO) and inducible nitric oxide synthase (iNOS) expression were determined by Griess reagent and western blotting, respectively. Inflammatory cytokines release was evaluated by ELISA and qRT-PCR. PI3K/Akt expression was analyzed by western blotting analysis. Curcumin significantly attenuated, in a dose-dependent manner, LPS-induced release of NO and pro-inflammatory cytokines, as well as iNOS expression. Interestingly, curcumin was able to reduce, again in a dose-dependent manner, PI3K/Akt phosphorylation as well as NF-κB activation in LPS-activated microglial cells. Overall these results suggest that curcumin plays an important role in the attenuation of LPS-induced inflammatory responses in microglial cells and that the mechanisms involve down-regulation of the PI3K/Akt signalling. PMID:27208432

  3. Microgliosis in the Injured Brain: Infiltrating Cells and Reactive Microglia Both Play a Role.

    PubMed

    Li, Ting; Zhang, Shengxiang

    2016-04-01

    Microgliosis is an intense reaction of CNS microglia to pathogenic insults. One of the characteristic features of microgliosis is an increase in the number of activated microglia at the site of lesion. Ontogenically, microglia are considered to be of mesodermal lineage in the adult CNS, but the origin of the accumulated microglia in pathological conditions remains controversial. Some studies indicate that circulating cells from the bloodstream can infiltrate the CNS and contribute to microglial pool, but some studies suggest that local expansion of reactive microglia is the sole source for parenchymal microglia. Recent data suggest that latent progenitors may also exist in the CNS. Available evidence suggests that multiple sources of microglia may exist under various neurological conditions. In this review, we compare the prevalent views and supporting evidence from different experimental models and provide an overview on the origins of microgliosis. PMID:25672621

  4. Telmisartan prevention of LPS-induced microglia activation involves M2 microglia polarization via CaMKKβ-dependent AMPK activation.

    PubMed

    Xu, Yuan; Xu, Yazhou; Wang, Yurong; Wang, Yunjie; He, Ling; Jiang, Zhenzhou; Huang, Zhangjian; Liao, Hong; Li, Jia; Saavedra, Juan M; Zhang, Luyong; Pang, Tao

    2015-11-01

    Brain inflammation plays an important role in the pathophysiology of many psychiatric and neurological diseases. During brain inflammation, microglia cells are activated, producing neurotoxic molecules and neurotrophic factors depending on their pro-inflammatory M1 and anti-inflammatory M2 phenotypes. It has been demonstrated that Angiotensin II type 1 receptor blockers (ARBs) ameliorate brain inflammation and reduce M1 microglia activation. The ARB telmisartan suppresses glutamate-induced upregulation of inflammatory genes in cultured primary neurons. We wished to clarify whether telmisartan, in addition, prevents microglia activation through polarization to an anti-inflammatory M2 phenotype. We found that telmisartan promoted M2 polarization and reduced M1 polarization in LPS-stimulated BV2 and primary microglia cells, effects partially dependent on PPARγ activation. The promoting effects of telmisartan on M2 polarization, were attenuated by an AMP-activated protein kinase (AMPK) inhibitor or AMPK knockdown, indicating that AMPK activation participates on telmisartan effects. Moreover, in LPS-stimulated BV2 cells, telmisartan enhancement of M2 gene expression was prevented by the inhibitor STO-609 and siRNA of calmodulin-dependent protein kinase kinase β (CaMKKβ), an upstream kinase of AMPK. Furthermore, telmisartan enhanced brain AMPK activation and M2 gene expression in a mouse model of LPS-induced neuroinflammation. In addition, telmisartan reduced the LPS-induced sickness behavior in this in vivo model, and this effect was prevented by prior administration of an AMPK inhibitor. Our results indicate that telmisartan can be considered as a novel AMPK activator, suppressing microglia activation by promoting M2 polarization. Telmisartan may provide a novel, safe therapeutic approach to treat brain disorders associated with enhanced inflammation. PMID:26188187

  5. Selective Activation of Microglia Facilitates Synaptic Strength

    PubMed Central

    Clark, Anna K.; Gruber-Schoffnegger, Doris; Drdla-Schutting, Ruth; Gerhold, Katharina J.; Malcangio, Marzia

    2015-01-01

    Synaptic plasticity is thought to be initiated by neurons only, with the prevailing view assigning glial cells mere specify supportive functions for synaptic transmission and plasticity. We now demonstrate that glial cells can control synaptic strength independent of neuronal activity. Here we show that selective activation of microglia in the rat is sufficient to rapidly facilitate synaptic strength between primary afferent C-fibers and lamina I neurons, the first synaptic relay in the nociceptive pathway. Specifically, the activation of the CX3CR1 receptor by fractalkine induces the release of interleukin-1β from microglia, which modulates NMDA signaling in postsynaptic neurons, leading to the release of an eicosanoid messenger, which ultimately enhances presynaptic neurotransmitter release. In contrast to the conventional view, this form of plasticity does not require enhanced neuronal activity to trigger the events leading to synaptic facilitation. Augmentation of synaptic strength in nociceptive pathways represents a cellular model of pain amplification. The present data thus suggest that, under chronic pain states, CX3CR1-mediated activation of microglia drives the facilitation of excitatory synaptic transmission in the dorsal horn, which contributes to pain hypersensitivity in chronic pain states. PMID:25788673

  6. Soluble complement complex C5b-9 promotes microglia activation.

    PubMed

    Yang, Chao; Yang, Li; Liu, Yong

    2014-02-15

    Soluble C5b-9 has been described as a pro-inflammatory mediator that triggers cell activation rather than inducing cell death. Microglia is the most important immune cell involved in inflammatory response in the CNS. Although microglia activation induced by various stimuli has been well characterized, the role of C5b-9 in microglia has not been well studied. In the current experiment, we utilized assembled functional C5b-9 to treat microglia and analyzed the function. We found that soluble C5b-9 could promote microglia activation by up-regulation of costimulatory molecules and increase cytokine secretion. Our results suggested that soluble C5b-9 possessed immunoregulatory potential on microglia. PMID:24434076

  7. 18β-glycyrrhetinic acid suppresses experimental autoimmune encephalomyelitis through inhibition of microglia activation and promotion of remyelination.

    PubMed

    Zhou, Jieru; Cai, Wei; Jin, Min; Xu, Jingwei; Wang, Yanan; Xiao, Yichuan; Hao, Li; Wang, Bei; Zhang, Yanyun; Han, Jie; Huang, Rui

    2015-01-01

    Microglia are intrinsic immune cells in the central nervous system (CNS). The under controlled microglia activation plays important roles in inflammatory demyelination diseases, such as multiple sclerosis (MS). However, the means to modulate microglia activation as a therapeutic modality and the underlying mechanisms remain elusive. Here we show that administration of 18β-glycyrrhetinic acid (GRA), by using both preventive and therapeutic treatment protocols, significantly suppresses disease severity of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. The treatment effect of GRA on EAE is attributed to its regulatory effect on microglia. GRA-modulated microglia significantly decreased pro-inflammatory profile in the CNS through suppression of MAPK signal pathway. The ameliorated CNS pro-inflammatory profile prevented the recruitment of encephalitogenic T cells into the CNS, which alleviated inflammation-induced demyelination. In addition, GRA treatment promoted remyelination in the CNS of EAE mice. The induced remyelination can be mediated by the overcome of inflammation-induced blockade of brain-derived neurotrophic factor expression in microglia, as well as enhancing oligodendrocyte precursor cell proliferation. Collectively, our results demonstrate that GRA-modulated microglia suppresses EAE through inhibiting microglia activation-mediated CNS inflammation, and promoting neuroprotective effect of microglia, which represents a potential therapeutic strategy for MS and maybe other neuroinflammatory diseases associated with microglia activation. PMID:26329786

  8. Aldose reductase mediates retinal microglia activation.

    PubMed

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

    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(GFP) mice carrying AR mutant alleles to evaluate the role of AR on RMG activation and migration in vivo. When tested on an AR(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. PMID:27033597

  9. Microglia and neuroprotection.

    PubMed

    Chen, Zhihong; Trapp, Bruce D

    2016-01-01

    Microglia were first identified over a century ago, but our knowledge about their ontogeny and functions has significantly expanded only recently. Microglia colonize the central nervous system (CNS) in utero and play essential roles in brain development. Once neural development is completed, microglia function as the resident innate immune cells of the CNS by surveying their microenvironment and becoming activated when the CNS is challenged by infection, injury, or disease. Despite the traditional view of microglia as being destructive in neurological diseases, recent studies have shown that microglia maintain CNS homeostasis and protect the CNS under various pathological conditions. Microglia can be prophylactically activated by modeling infection with systemic lipopolysaccharide injections and these activated microglia can protect the brain from traumatic injury through modulation of neuronal synapses. Microglia can also protect the CNS by promoting neurogenesis, clearing debris, and suppressing inflammation in diseases such as stroke, autism, and Alzheimer's. Microglia are the resident innate immune cells of the CNS. Despite the traditional view of microglia as being destructive in neurological diseases, recent studies have shown that they maintain tissue homeostasis and protect the CNS under various pathological conditions. They achieve so by clearing debris, promoting neurogenesis, suppressing inflammation and stripping inhibitory synapses. This review summarizes recent advances of our understanding on the multi-dimensional neuroprotective roles of microglia. PMID:25693054

  10. Early microglia activation in a mouse model of chronic glaucoma

    PubMed Central

    Bosco, Alejandra; Steele, Michael R.; Vetter, Monica L.

    2014-01-01

    Changes in microglial cell activation and distribution are associated with neuronal decline in the CNS, particularly under pathological conditions. Activated microglia converge on the initial site of axonal degeneration in human glaucoma, yet, their part in its pathophysiology remains unresolved. To begin with, it is unknown whether microglia activation precedes or is a late consequence of retinal ganglion cell (RGC) neurodegeneration. Here, we address this critical element in DBA/2J (D2) mice, an established model of chronic inherited glaucoma, using as a control the congenic substrain DBA/2J Gpnmb+/SjJ (D2G), which is not affected by glaucoma. We analyzed the spatial distribution and timecourse of microglial changes in the retina, as well as within the proximal optic nerve prior to and throughout ages when neurodegeneration has been reported. Exclusively in D2 mice, we detected early microglia clustering in the inner central retina and unmyelinated optic nerve regions, with microglia activation peaking by 3 months of age. Between 5 and 8 months of age, activated microglia persisted and concentrated in the optic disc, but also localized to the retinal periphery. Collectively, our findings suggest microglia activation is an early alteration in the retina and optic nerve in D2 glaucoma, potentially contributing to disease onset or progression. Ultimately, detection of microglial activation may have value in early disease diagnosis, while modulation of microglial responses may alter disease progression. PMID:21246546

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

    PubMed Central

    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. PMID:26388737

  12. Microglia Sculpt Postnatal Neural Circuits in an Activity and Complement-Dependent Manner

    PubMed Central

    Schafer, Dorothy P; Lehrman, Emily K; Kautzman, Amanda G; Koyama, Ryuta; Mardinly, Alan R; Yamasaki, Ryo; Ransohoff, Richard M; Greenberg, Michael E; Barres, Ben A; Stevens, Beth

    2012-01-01

    SUMMARY Microglia are the resident CNS immune cells and active surveyors of the extracellular environment. While past work has focused on the role of these cells during disease, recent imaging studies reveal dynamic interactions between microglia and synaptic elements in the healthy brain. Despite these intriguing observations, the precise function of microglia at remodeling synapses and the mechanisms that underlie microglia-synapse interactions remain elusive. In the current study, we demonstrate a role for microglia in activity-dependent synaptic pruning in the postnatal retinogeniculate system. We show that microglia engulf presynaptic inputs during peak retinogeniculate pruning and engulfment is dependent upon neural activity and the microglia-specific phagocytic signaling pathway, complement receptor 3(CR3)/C3. Furthermore, disrupting microglia-specific CR3/C3 signaling resulted in sustained deficits in synaptic connectivity. These results define a role for microglia during postnatal development and identify underlying mechanisms by which microglia engulf and remodel developing synapses. PMID:22632727

  13. Activation of Bone Marrow-Derived Microglia Promotes Photoreceptor Survival in Inherited Retinal Degeneration

    PubMed Central

    Sasahara, Manabu; Otani, Atsushi; Oishi, Akio; Kojima, Hiroshi; Yodoi, Yuko; Kameda, Takanori; Nakamura, Hajime; Yoshimura, Nagahisa

    2008-01-01

    The role of microglia in neurodegeneration is controversial, although microglial activation in the retina has been shown to provide an early response against infection, injury, ischemia, and degeneration. Here we show that endogenous bone marrow (BM)-derived microglia play a protective role in vascular and neural degeneration in the retinitis pigmentosa model of inherited retinal degeneration. BM-derived cells were recruited to the degenerating retina where they differentiated into microglia and subsequently localized to the degenerating vessels and neurons. Inhibition of stromal-derived factor-1 in the retina reduced the number of BM-derived microglia and accelerated the rate of neurovascular degeneration. Systemic depletion of myeloid progenitors also accelerated the degenerative process. Conversely, activation of BM-derived myeloid progenitors by systemic administration of both granulocyte colony-stimulating factor and erythropoietin resulted in the deceleration of retinal degeneration and the promotion of cone cell survival. These data indicate that BM-derived microglia may play a protective role in retinitis pigmentosa. Functional activation of BM-derived myeloid progenitors by cytokine therapy may provide a novel strategy for the treatment of inherited retinal degeneration and other neurodegenerative diseases, regardless of the underlying genetic defect. PMID:18483210

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

    PubMed Central

    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. PMID:27533766

  15. Activated microglia in acute encephalopathy with biphasic seizures and late reduced diffusion.

    PubMed

    Fujita, Yuji; Takanashi, Jun-Ichi; Takei, Haruka; Ota, Setsuo; Fujii, Katsunori; Sakuma, Hiroshi; Hayashi, Masaharu

    2016-07-15

    Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype of infectious pediatric encephalopathy in Japan. The exact pathogenesis of and the best therapeutic strategy for AESD are uncertain. We firstly performed a brain biopsy in a 2-year-old boy with AESD associated with RS viral infection, which revealed activated ameoboid microglia accumulation around degenerated neuron, and astrogliosis in the affected cortex. Glutamate released from activated microglia may play an important role in the pathogenesis of AESD, which is compatible with the previous report of magnetic resonance spectroscopy showing elevated glutamate. PMID:27288783

  16. Differential Pro-Inflammatory Responses of Astrocytes and Microglia Involve STAT3 Activation in Response to 1800 MHz Radiofrequency Fields

    PubMed Central

    Lu, Yonghui; He, Mindi; Zhang, Yang; Xu, Shangcheng; Zhang, Lei; He, Yue; Chen, Chunhai; Liu, Chuan; Pi, Huifeng; Yu, Zhengping; Zhou, Zhou

    2014-01-01

    Microglia and astrocytes play important role in maintaining the homeostasis of central nervous system (CNS). Several CNS impacts have been postulated to be associated with radiofrequency (RF) electromagnetic fields exposure. Given the important role of inflammation in neural physiopathologic processes, we investigated the pro-inflammatory responses of microglia and astrocytes and the involved mechanism in response to RF fields. Microglial N9 and astroglial C8-D1A cells were exposed to 1800 MHz RF for different time with or without pretreatment with STAT3 inhibitor. Microglia and astrocytes were activated by RF exposure indicated by up-regulated CD11b and glial fibrillary acidic protein (GFAP). However, RF exposure induced differential pro-inflammatory responses in astrocytes and microglia, characterized by different expression and release profiles of IL-1β, TNF-α, IL-6, PGE2, nitric oxide (NO), inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). Moreover, the RF exposure activated STAT3 in microglia but not in astrocytes. Furthermore, the STAT3 inhibitor Stattic ameliorated the RF-induced release of pro-inflammatory cytokines in microglia but not in astrocytes. Our results demonstrated that RF exposure differentially induced pro-inflammatory responses in microglia and astrocytes, which involved differential activation of STAT3 in microglia and astrocytes. Our data provide novel insights into the potential mechanisms of the reported CNS impacts associated with mobile phone use and present STAT3 as a promising target to protect humans against increasing RF exposure. PMID:25275372

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

    SciTech Connect

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

    2009-07-01

    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{sub 2} (PGE{sub 2}) in the proliferation of astrocytes. The proliferation of astrocytes was measured by BrdU incorporation. The level of PGE{sub 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{sub 2} in enhanced astrocyte proliferation was suggested by the findings that PGE{sub 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{sub 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{sub 2} to the media significantly induced astrocyte proliferation. These results indicate that microglial PGE{sub 2} plays an important role in astrocyte proliferation, identifying PGE{sub 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{sub 2} in astrocyte proliferation and in suggesting a potential avenue in the use of anti-inflammatory agents for the therapy of astroglioma.

  18. Minocycline attenuates microglia activation and blocks the long-term epileptogenic effects of early-life seizures.

    PubMed

    Abraham, Jayne; Fox, Patrick D; Condello, Carlo; Bartolini, Alyssa; Koh, Sookyong

    2012-05-01

    Innate immunity mediated by microglia appears to play a crucial role in initiating and propagating seizure-induced inflammatory responses. To address the role of activated microglia in the pathogenesis of childhood epilepsy, we first examined the time course of microglia activation following kainic acid-induced status epilepticus (KA-SE) in Cx3cr1(GFP/+) transgenic mice whose microglia are fluorescently labeled. We then determined whether this seizure-induced microglia activation primes the central immune response to overreact and to increase the susceptibility to a second seizure later in life. We used an inhibitor of microglia activation, minocycline, to block the seizure-induced inflammation to determine whether innate immunity plays a causal role in mediating the long-term epileptogenic effects of early-life seizure. First status epilepticus was induced at postnatal day (P) 25 and a second status at P39. KA-SE at P25 caused nearly a two-fold increase in microglia activation within 24h. Significant seizure-induced activation persisted for 7 days and returned to baseline by 14 days. P39 animals with prior exposure to KA-SE not only responded with greater microglial activation in response to "second hit" of KA, but shorter latency to express seizures. Inhibition of seizure-induced inflammation by 7 day minocycline post-treatment abrogated both the exaggerated microglia activation and the increased susceptibility to the second seizure later in life. The priming effect of early-life seizures is accompanied by modified and rapidly reactivated microglia. Our results suggest that anti-inflammatory therapy after SE may be useful to block the epileptogenic process and mitigate the long-term damaging effects of early-life seizures. PMID:22366182

  19. Differential activation of microglia after experimental spinal cord injury.

    PubMed

    Watanabe, T; Yamamoto, T; Abe, Y; Saito, N; Kumagai, T; Kayama, H

    1999-03-01

    This study sought to experimentally clarify time-dependent, differential microglial activation at various spinal cord locations in response to injury. The spinal cords of Wistar rats were either sharply transected at the Th 11 or subjected to compression at the same site. Immediately to 4 weeks after injury, each spinal cord was fixed and cut into longitudinal frozen sections, and was immunostained with OX42 for resident and activated microglia, OX-6 for activated microglia, GFAP for activated astrocytes, and biotinylated BS-I, a lectin for both resident and activated microglia. From three to 24 hours after injury, we observed a narrow belt around the transection site in which OX42 positive microglia were dramatically reduced in number, or often absent. BS-I labeling of the zone disclosed the rapid transformation of those microglia possessing typical antler-like processes to macrophage-like cells. At day 1 and thereafter, the zone of reduced OX42 immunoreactivity was gradually replaced by macrophage-like OX42-positive round cells, and the lesion itself was ultimately capped by fibrogliotic scar tissue. By 2-4 weeks postinjury, another phase of microglial activation was observed in those white matter tracts undergoing Wallerian degeneration. These microglia characterized by the presence of newly-expressed MHC class II antigens. We posit that the decreased OX42 immunoreactivity suggests that CR3 is quickly saturated by activated iC3b and internalized, but not down-regulated. The trigger for this transformation most likely occurs through signaling by iC3b-saturated CR3. In contrast, microglia activation along those degenerating tracts undergoing Wallerian degeneration does not appear to be CR3-related, as the CR3 is upregulated. These observations indicate microglia have at least two different spatial and temporal patterns of activation. One is rapid and most likely involves the blood-borne complement activating system. The other accompanies Wallerian degeneration and

  20. Microglia mechanics: immune activation alters traction forces and durotaxis

    PubMed Central

    Bollmann, Lars; Koser, David E.; Shahapure, Rajesh; Gautier, Hélène O. B.; Holzapfel, Gerhard A.; Scarcelli, Giuliano; Gather, Malte C.; Ulbricht, Elke; Franze, Kristian

    2015-01-01

    Microglial cells are key players in the primary immune response of the central nervous system. They are highly active and motile cells that chemically and mechanically interact with their environment. While the impact of chemical signaling on microglia function has been studied in much detail, the current understanding of mechanical signaling is very limited. When cultured on compliant substrates, primary microglial cells adapted their spread area, morphology, and actin cytoskeleton to the stiffness of their environment. Traction force microscopy revealed that forces exerted by microglia increase with substrate stiffness until reaching a plateau at a shear modulus of ~5 kPa. When cultured on substrates incorporating stiffness gradients, microglia preferentially migrated toward stiffer regions, a process termed durotaxis. Lipopolysaccharide-induced immune-activation of microglia led to changes in traction forces, increased migration velocities and an amplification of durotaxis. We finally developed a mathematical model connecting traction forces with the durotactic behavior of migrating microglial cells. Our results demonstrate that microglia are susceptible to mechanical signals, which could be important during central nervous system development and pathologies. Stiffness gradients in tissue surrounding neural implants such as electrodes, for example, could mechanically attract microglial cells, thus facilitating foreign body reactions detrimental to electrode functioning. PMID:26441534

  1. Microglia is activated by astrocytes in trimethyltin intoxication

    SciTech Connect

    Roehl, Claudia . E-mail: claudia.roehl@gmx.net; Sievers, Jobst

    2005-04-01

    Microglia participates in most acute and chronic neuropathologies and its activation appears to involve interactions with neurons and other glial cells. Trimethyltin (TMT)-induced brain damage is a well-characterized model of neurodegeneration, in which microglial activation occurs before neuronal degeneration. The aim of this in vitro study was to investigate the role of astroglia in TMT-induced microgliosis by using nitric oxide (NO), inducible NO synthase (iNOS), and morphological changes as parameters for microglial activation. Our investigation discusses (a) whether microglial cells can be activated directly by TMT; (b) if astroglial cells are capable of triggering or modulating microglial activation; (c) how the morphology and survival of microglia and astrocytes are affected by TMT treatment; and (d) whether microglial-astroglial interactions depend on direct cell contact or on soluble factors. Our results show that microglia are more vulnerable to TMT than astrocytes are and cannot be activated directly by TMT with regard to the examined parameters. In bilayer coculture with viable astroglial cells, microglia produce NO in significant amounts at subcytotoxic concentrations of TMT (20 {mu}mol/l). At these TMT concentrations, microglial cells in coculture convert into small round cells without cell processes, whereas flat, fibroblast-like astrocytes convert into thin process bearing stellate cells with a dense and compact cell body. We conclude that astrocytes trigger microglial activation after treatment with TMT, although the mechanisms of this interaction remain unknown.

  2. miR-Let7A Modulates Autophagy Induction in LPS-Activated Microglia

    PubMed Central

    Song, Juhyun; Oh, Yumi

    2015-01-01

    Microglia regulate the secretion of various immunomediators in central nervous system diseases. Microglial autophagy is the crucial process for cell's survival and cytokine productions. Recent studies have reported that several microRNAs are involved in the autophagy system. miR-Let7A is such a microRNA that plays a role in various inflammation responses, and is magnified as a key modulator particularly in the autophagy system. In present study, we investigated whether miR-Let7A is involved in autophagy in activating microglia. Overexpression of miR-Let7A in LPS-stimulated BV2 microglial cells promoted the induction of the autophagy related factors such as LC3II, Beclin1, and ATG3. Our results suggest a potential role of miR-Let7A in the autophagy process of microglia during CNS inflammation. PMID:26113790

  3. Functionally charged nanosize particles differentially activate BV2 microglia.

    EPA Science Inventory

    The effect of particle surface charge on the biological activation of immortalized mouse microglia (BV2) was examined. Nanosize (860-950 nm) spherical polystyrene microparticles (SPM) were coated with carboxyl (COOH-) or dimethyl amino (CH3)2-N- groups to give a net negative or p...

  4. Beta-glucan activates microglia without inducing cytokine production in Dectin-1-dependent manner.

    PubMed

    Shah, Vaibhav B; Huang, Yongcheng; Keshwara, Rohan; Ozment-Skelton, Tammy; Williams, David L; Keshvara, Lakhu

    2008-03-01

    Microglia are the resident mononuclear phagocytic cells that are critical for innate and adaptive responses within the CNS. Like other immune cells, microglia recognize and are activated by various pathogen-associated molecular patterns. beta-glucans are pathogen-associated molecular patterns present within fungal cell walls that are known to trigger protective responses in a number of immune cells. In an effort to better understand microglial responses to beta-glucans and the underlying response pathways, we sought to determine whether Dectin-1, a major beta-glucan receptor recently identified in leukocytes, plays a similar role in beta-glucan-induced activation in microglia. In this study, we report that Dectin-1 is indeed expressed on the surface of murine primary microglia, and engagement of the receptor with particulate beta-glucan resulted in an increase in tyrosine phosphorylation of spleen tyrosine kinase, a hallmark feature of the Dectin-1 signaling pathway. Moreover, phagocytosis of beta-glucan particles and subsequent intracellular production of reactive oxygen species were also mediated by Dectin-1. However, unlike in macrophages and dendritic cells, beta-glucan-mediated microglial activation did not result in significant production of cytokines or chemokines; thus, the interaction of microglial Dectin-1 with glucan elicits a unique response. Our results suggest that the Dectin-1 pathway may play an important role in antifungal immunity in the CNS. PMID:18292498

  5. Inhibition of Neuroinflammation in LPS-Activated Microglia by Cryptolepine.

    PubMed

    Olajide, Olumayokun A; Bhatia, Harsharan S; de Oliveira, Antonio C P; Wright, Colin W; Fiebich, Bernd L

    2013-01-01

    Cryptolepine, an indoloquinoline alkaloid in Cryptolepis sanguinolenta, has anti-inflammatory property. In this study, we aimed to evaluate the effects of cryptolepine on lipopolysaccharide (LPS)- induced neuroinflammation in rat microglia and its potential mechanisms. Microglial activation was induced by stimulation with LPS, and the effects of cryptolepine pretreatment on microglial activation and production of proinflammatory mediators, PGE2/COX-2, microsomal prostaglandin E2 synthase and nitric oxide/iNOS were investigated. We further elucidated the role of Nuclear Factor-kappa B (NF- κ B) and the mitogen-activated protein kinases in the antiinflammatory actions of cryptolepine in LPS-stimulated microglia. Our results showed that cryptolepine significantly inhibited LPS-induced production of tumour necrosis factor-alpha (TNF α ), interleukin-6 (IL-6), interleukin-1beta (IL-1 β ), nitric oxide, and PGE2. Protein and mRNA levels of COX-2 and iNOS were also attenuated by cryptolepine. Further experiments on intracellular signalling mechanisms show that I κ B-independent inhibition of NF- κ B nuclear translocation contributes to the anti-neuroinflammatory actions of cryptolepine. Results also show that cryptolepine inhibited LPS-induced p38 and MAPKAPK2 phosphorylation in the microglia. Cell viability experiments revealed that cryptolepine (2.5 and 5  μ M) did not produce cytotoxicity in microglia. Taken together, our results suggest that cryptolepine inhibits LPS-induced microglial inflammation by partial targeting of NF- κ B signalling and attenuation of p38/MAPKAPK2. PMID:23737832

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

    PubMed Central

    Yang, Qingchan; Wang, Yan; Feng, Jing; Cao, Jie; Chen, Baoyuan

    2013-01-01

    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. PMID:23950649

  7. Presenilin 2 influences miR146 level and activity in microglia.

    PubMed

    Jayadev, Suman; Case, Amanda; Alajajian, Betty; Eastman, Alison J; Möller, Thomas; Garden, Gwenn A

    2013-12-01

    Microglia, the resident innate immune cells of the CNS, are the primary defenders against microbes and critical to CNS remodeling. Dysregulation of microglial behavior can lead to unchecked pro-inflammatory activity and subsequent neurodegeneration. The molecular mechanisms leading to chronic inflammation and microglial dysfunction in neurodegenerative diseases are not well-understood. It is known that patients with Presenilin 2 (PS2) mutations develop autosomal dominant Alzheimer disease. We have shown that a lack of normal PS2 function is associated with exaggerated microglia pro-inflammatory responses in vitro. To identify pathways by which PS2 regulates microglia and determine how PS2 dysfunction may lead to altered inflammatory pathways, we pursued an unbiased array approach to assess differential expression of microRNAs between murine PS2 knockout (KO) and wild-type microglia. We identified miR146, a negative regulator of monocyte pro-inflammatory response, as constitutively down-regulated in PS2 KO microglia. Consistent with a state of miR146 suppression, we found that PS2 KO microglia express higher levels of the miR146 target protein interleukin-1 receptor-associated kinase-1, and have increased NFκB transcriptional activity. We hypothesize that PS2 impacts microglial responses through modulation of miR146a. PS2 dysfunction, through aging or mutation, may contribute to neurodegeneration by influencing the pro-inflammatory behavior of microglia. Presenilin 2 (PS2), a membrane associated protease, has been implicated in the pathogenesis of Alzheimer disease. We have previously shown that PS2 plays an important role in curbing the proinflammatory response in microglia. Here, we report the novel finding that PS2 participates in maintaining the basal and cytokine induced expression of the innate immunity regulating microRNA, miR146. These data suggest one mechanism by which PS2 works to reign in proinflammatory microglial behavior and that PS2 dysfunction or

  8. Satellite microglia show spontaneous electrical activity that is uncorrelated with activity of the attached neuron.

    PubMed

    Wogram, Emile; Wendt, Stefan; Matyash, Marina; Pivneva, Tatyana; Draguhn, Andreas; Kettenmann, Helmut

    2016-06-01

    Microglia are innate immune cells of the brain. We have studied a subpopulation of microglia, called satellite microglia. This cell type is defined by a close morphological soma-to-soma association with a neuron, indicative of a direct functional interaction. Indeed, ultrastructural analysis revealed closely attached plasma membranes of satellite microglia and neurons. However, we found no apparent morphological specializations of the contact, and biocytin injection into satellite microglia showed no dye-coupling with the apposed neurons or any other cell. Likewise, evoked local field potentials or action potentials and postsynaptic potentials of the associated neuron did not lead to any transmembrane currents or non-capacitive changes in the membrane potential of the satellite microglia in the cortex and hippocampus. Both satellite and non-satellite microglia, however, showed spontaneous transient membrane depolarizations that were not correlated with neuronal activity. These events could be divided into fast-rising and slow-rising depolarizations, which showed different characteristics in satellite and non-satellite microglia. Fast-rising and slow-rising potentials differed with regard to voltage dependence. The frequency of these events was not affected by the application of tetrodotoxin, but the fast-rising event frequency decreased after application of GABA. We conclude that microglia show spontaneous electrical activity that is uncorrelated with the activity of adjacent neurons. PMID:27060918

  9. Greater Glucocorticoid Receptor Activation in Hippocampus of Aged Rats Sensitizes Microglia

    PubMed Central

    Barrientos, Ruth M.; Thompson, Vanessa M.; Kitt, Meagan M.; Amat, Jose; Hale, Matthew W.; Frank, Matthew G.; Crysdale, Nicole Y.; Stamper, Christopher E.; Hennessey, Patrick A.; Watkins, Linda R.; Spencer, Robert L.; Lowry, Christopher A.; Maier, Steven F.

    2014-01-01

    Healthy aging individuals are more likely to suffer profound memory impairments following an immune challenge than are younger adults. These challenges produce a brain inflammatory response that is exaggerated with age. Sensitized microglia found in the normal aging brain are responsible for this amplified response, which in turn interferes with processes involved in memory formation. Here, we examine factors that may lead aging to sensitize microglia. Aged rats exhibited higher CORT levels in the hippocampus, but not in plasma, throughout the daytime (diurnal inactive phase). These elevated hippocampal CORT levels were associated with increased hippocampal 11β-HSD1 protein expression, the enzyme that catalyzes glucocorticoid formation, and greater hippocampal glucocorticoid receptor (GR) activation. Intracisternal administration of mifepristone, a GR antagonist, effectively reduced immune-activated proinflammatory responses, specifically from hippocampal microglia, and prevented E. coli-induced memory impairments in aged rats. Voluntary exercise as a therapeutic intervention significantly reduced total hippocampal GR expression. These data strongly suggest that increased GR activation in the aged hippocampus plays a critical role in sensitizing microglia. PMID:25559333

  10. Activated microglia are less vulnerable to hemin toxicity due to nitric oxide-dependent inhibition of JNK and p38 MAPK activation.

    PubMed

    Cai, Ying; Cho, Geum-Sil; Ju, Chung; Wang, Si-Ling; Ryu, Jong Hoon; Shin, Chan Young; Kim, Hee-Sun; Nam, Kung-Woo; Jalin, Angela M A Anthony; Sun, Woong; Choi, In-Young; Kim, Won-Ki

    2011-08-01

    In intracerebral hemorrhage, microglia become rapidly activated and remove the deposited blood and cellular debris. To survive in a harmful hemorrhagic or posthemorrhagic condition, activated microglia must be equipped with appropriate self-defensive mechanism(s) to resist the toxicity of hemin, a component released from damaged RBCs. In the current study, we found that activation of microglia by pretreatment with LPS markedly reduced their vulnerability to hemin toxicity in vitro. Similarly, intracorpus callosum microinjection of LPS prior to hemin treatment reduced the brain tissue damage caused by hemin and increased microglial density in the penumbra in rats. LPS induced the expressions of inducible NO synthase (iNOS) and heme oxygenase (HO)-1, the rate-limiting enzyme in heme degradation in microglia. The preventive effect by LPS was significantly diminished by an iNOS inhibitor, L-N(6)-(1-iminoethyl)lysine, whereas it was mimicked by a NO donor, diethylamine-NONOate, both suggesting the crucial role of NO in the modulation of hemin-induced toxicity in activated microglia. We further found that NO reduced hemin toxicity via inhibition of hemin-induced activation of JNK and p38 MAPK pathways in microglia. Whereas HO-1 expression in LPS-stimulated microglia was markedly blocked by L-N(6)-(1-iminoethyl)lysine, the HO-1 inhibitor, tin protoporphyrin, increased iNOS expression and decreased the susceptibility of LPS-activated microglia to hemin toxicity. The data indicate that the mutual interaction between NO and HO-1 plays a critical role in modulating the adaptive response of activated microglia to hemin toxicity. Better understanding of the survival mechanism of activated microglia may provide a therapeutic strategy to attenuate the devastating intracerebral hemorrhagic injury. PMID:21709153

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

    PubMed

    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

  12. Systemic and Intravitreal Delivery of Dendrimers to Activated Microglia/Macrophage in Ischemia/Reperfusion Mouse Retina

    PubMed Central

    Kambhampati, Siva P.; Clunies-Ross, Alexander J. M.; Bhutto, Imran; Mishra, Manoj K.; Edwards, Malia; McLeod, D. Scott; Kannan, Rangaramanujam M.; Lutty, Gerard

    2015-01-01

    Purpose Microglial activation and associated neuroinflammation play a key role in the pathogenesis of many diseases of the retina, including viral infection, diabetes, and retinal degeneration. Strategies to target activated microglia and macrophages and attenuate inflammation may be valuable in treating these diseases. We seek to develop dendrimer-based formulations that target retinal microglia and macrophages in a pathology-dependent manner, and deliver drugs, either intravenously or intravitreally. Methods Retinal uptake of cyanine dye (Cy5)-conjugated dendrimer (D-Cy5) was assessed in normal and ischemia/reperfusion (I/R) mouse eyes. Microglia/macrophage uptake of the dendrimer was assessed with immunofluorescence using rabbit Iba-1 antibody with Cy3-tagged secondary antibody (microglia/macrophage). Uptake in retina and other organs was quantified using fluorescence spectroscopy. Results Clearance of D-Cy5 from normal eyes was almost complete by 72 hours after intravitreal injection and 24 hours after intravenous delivery. In eyes with activated microglia after I/R injury, D-Cy5 was retained by activated microglia/macrophage (Iba1+ cells) up to 21 days after intravitreal and intravenous administration. In I/R eyes, the relative retention of intravitreal and intravenous D-Cy5 was comparable, if a 30-fold higher intravenous dose was used. Conclusions Intravitreal and systemic dendrimers target activated microglia and show qualitatively similar retinal biodistribution when administered by either route. Results provide proof-of-concept insights for developing dendrimer drug formulations as treatment options for retinal diseases associated with microglia or macrophage activation such as age-related macular degeneration, diabetic retinopathy, and retinal degenerations. PMID:26193917

  13. Inhibition of Neuroinflammation in LPS-Activated Microglia by Cryptolepine

    PubMed Central

    Olajide, Olumayokun A.; Bhatia, Harsharan S.; de Oliveira, Antonio C. P.; Wright, Colin W.; Fiebich, Bernd L.

    2013-01-01

    Cryptolepine, an indoloquinoline alkaloid in Cryptolepis sanguinolenta, has anti-inflammatory property. In this study, we aimed to evaluate the effects of cryptolepine on lipopolysaccharide (LPS)- induced neuroinflammation in rat microglia and its potential mechanisms. Microglial activation was induced by stimulation with LPS, and the effects of cryptolepine pretreatment on microglial activation and production of proinflammatory mediators, PGE2/COX-2, microsomal prostaglandin E2 synthase and nitric oxide/iNOS were investigated. We further elucidated the role of Nuclear Factor-kappa B (NF-κB) and the mitogen-activated protein kinases in the antiinflammatory actions of cryptolepine in LPS-stimulated microglia. Our results showed that cryptolepine significantly inhibited LPS-induced production of tumour necrosis factor-alpha (TNFα), interleukin-6 (IL-6), interleukin-1beta (IL-1β), nitric oxide, and PGE2. Protein and mRNA levels of COX-2 and iNOS were also attenuated by cryptolepine. Further experiments on intracellular signalling mechanisms show that IκB-independent inhibition of NF-κB nuclear translocation contributes to the anti-neuroinflammatory actions of cryptolepine. Results also show that cryptolepine inhibited LPS-induced p38 and MAPKAPK2 phosphorylation in the microglia. Cell viability experiments revealed that cryptolepine (2.5 and 5 μM) did not produce cytotoxicity in microglia. Taken together, our results suggest that cryptolepine inhibits LPS-induced microglial inflammation by partial targeting of NF-κB signalling and attenuation of p38/MAPKAPK2. PMID:23737832

  14. Microglia protect against brain injury and their selective elimination dysregulates neuronal network activity after stroke

    PubMed Central

    Szalay, Gergely; Martinecz, Bernadett; Lénárt, Nikolett; Környei, Zsuzsanna; Orsolits, Barbara; Judák, Linda; Császár, Eszter; Fekete, Rebeka; West, Brian L.; Katona, Gergely; Rózsa, Balázs; Dénes, Ádám

    2016-01-01

    Microglia are the main immune cells of the brain and contribute to common brain diseases. However, it is unclear how microglia influence neuronal activity and survival in the injured brain in vivo. Here we develop a precisely controlled model of brain injury induced by cerebral ischaemia combined with fast in vivo two-photon calcium imaging and selective microglial manipulation. We show that selective elimination of microglia leads to a striking, 60% increase in infarct size, which is reversed by microglial repopulation. Microglia-mediated protection includes reduction of excitotoxic injury, since an absence of microglia leads to dysregulated neuronal calcium responses, calcium overload and increased neuronal death. Furthermore, the incidence of spreading depolarization (SD) is markedly reduced in the absence of microglia. Thus, microglia are involved in changes in neuronal network activity and SD after brain injury in vivo that could have important implications for common brain diseases. PMID:27139776

  15. Microglia protect against brain injury and their selective elimination dysregulates neuronal network activity after stroke.

    PubMed

    Szalay, Gergely; Martinecz, Bernadett; Lénárt, Nikolett; Környei, Zsuzsanna; Orsolits, Barbara; Judák, Linda; Császár, Eszter; Fekete, Rebeka; West, Brian L; Katona, Gergely; Rózsa, Balázs; Dénes, Ádám

    2016-01-01

    Microglia are the main immune cells of the brain and contribute to common brain diseases. However, it is unclear how microglia influence neuronal activity and survival in the injured brain in vivo. Here we develop a precisely controlled model of brain injury induced by cerebral ischaemia combined with fast in vivo two-photon calcium imaging and selective microglial manipulation. We show that selective elimination of microglia leads to a striking, 60% increase in infarct size, which is reversed by microglial repopulation. Microglia-mediated protection includes reduction of excitotoxic injury, since an absence of microglia leads to dysregulated neuronal calcium responses, calcium overload and increased neuronal death. Furthermore, the incidence of spreading depolarization (SD) is markedly reduced in the absence of microglia. Thus, microglia are involved in changes in neuronal network activity and SD after brain injury in vivo that could have important implications for common brain diseases. PMID:27139776

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

    PubMed Central

    2013-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    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

  18. Rifampicin attenuates rotenone-induced inflammation via suppressing NLRP3 inflammasome activation in microglia.

    PubMed

    Liang, Yanran; Jing, Xiuna; Zeng, Zhifen; Bi, Wei; Chen, Ying; Wu, Xia; Yang, Lianhong; Liu, Jun; Xiao, Songhua; Liu, Shuqiong; Lin, Danyu; Tao, Enxiang

    2015-10-01

    A growing body of evidence has supported that environmental factors, such as exposure to heavy metal and pesticides, play an important role in the pathogenesis of Parkinson׳s disease (PD). Rotenone, the active ingredient in various pesticides, has been identified as an inducer of PD. It has been revealed that rotenone induces activation of microglia and generation of pro-inflammatory factors in PD. Our previous studies demonstrated that rifampicin possessed neural protective effect in PD. In this study, we aimed to study the effect of rifampicin on the inflammation induced by rotenone in microglia and the underlying mechanisms. Results demonstrated that rifampicin pretreatment significantly reduced rotenone-induced cytotoxicity and gene expression of IL-1β in BV2 microglia. Moreover, western blot analysis verified that rifampicin pretreatment suppressed NLRP3 inflammasome activation via inhibiting caspase-1 cleavage and protein expression of NLRP3. As it is indicated that reactive oxidative stress (ROS) is one of the activators for NLRP3 inflammasome, we further employed 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining and Rhodamine123 staining to detect intracellular ROS and mitochondrial membrane potential (MMP), respectively. Results confirmed that rifampicin obviously reduced intracellular ROS and reversed loss of MMP in BV2 cells treated by rotenone. Taken together, our data indicate that rifampicin pretreatment inhibits maturation of IL-1β and neuroinflammation induced by rotenone via attenuating NLRP3 inflammasome activation. Rifampicin might emerge as a promising candidate for modulating neuroinflammation in PD. PMID:26086368

  19. Progranulin Deficiency Promotes Circuit-Specific Synaptic Pruning by Microglia via Complement Activation.

    PubMed

    Lui, Hansen; Zhang, Jiasheng; Makinson, Stefanie R; Cahill, Michelle K; Kelley, Kevin W; Huang, Hsin-Yi; Shang, Yulei; Oldham, Michael C; Martens, Lauren Herl; Gao, Fuying; Coppola, Giovanni; Sloan, Steven A; Hsieh, Christine L; Kim, Charles C; Bigio, Eileen H; Weintraub, Sandra; Mesulam, Marek-Marsel; Rademakers, Rosa; Mackenzie, Ian R; Seeley, William W; Karydas, Anna; Miller, Bruce L; Borroni, Barbara; Ghidoni, Roberta; Farese, Robert V; Paz, Jeanne T; Barres, Ben A; Huang, Eric J

    2016-05-01

    Microglia maintain homeostasis in the brain, but whether aberrant microglial activation can cause neurodegeneration remains controversial. Here, we use transcriptome profiling to demonstrate that deficiency in frontotemporal dementia (FTD) gene progranulin (Grn) leads to an age-dependent, progressive upregulation of lysosomal and innate immunity genes, increased complement production, and enhanced synaptic pruning in microglia. During aging, Grn(-/-) mice show profound microglia infiltration and preferential elimination of inhibitory synapses in the ventral thalamus, which lead to hyperexcitability in the thalamocortical circuits and obsessive-compulsive disorder (OCD)-like grooming behaviors. Remarkably, deleting C1qa gene significantly reduces synaptic pruning by Grn(-/-) microglia and mitigates neurodegeneration, behavioral phenotypes, and premature mortality in Grn(-/-) mice. Together, our results uncover a previously unrecognized role of progranulin in suppressing aberrant microglia activation during aging. These results represent an important conceptual advance that complement activation and microglia-mediated synaptic pruning are major drivers, rather than consequences, of neurodegeneration caused by progranulin deficiency. PMID:27114033

  20. 15-O-Acetyl-3-O-benzoylcharaciol and helioscopinolide A, two diterpenes isolated from Euphorbia helioscopia suppress microglia activation.

    PubMed

    Wang, Hao; Liu, Yu; Zhang, Jingling; Xu, Jing; Cui, Chun-Ai; Guo, Yuanqiang; Jin, Da-Qing

    2016-01-26

    Microglia activation plays an important role in the pathogenesis of various neurodegenerative diseases by producing neurotoxic factors. In the present study, we found that two diterpenes isolated from Euphorbia helioscopia, 15-O-Acetyl-3-O-benzoylcharaciol and helioscopinolide A suppressed NO and PGE2 production by inhibition of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in lipopolysaccharide (LPS)-stimulated BV2 microglia cells. The diterpenes also inhibited the production of ROS and proinflammatory cytokines including interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α, the mechanism involved the NF-κB but not Akt and mitogen-activated protein kinase (MAPK) pathway. Moreover, the two diterpenes also attenuate microglia activation-mediated neuronal death. These results suggest that 15-O-Acetyl-3-O-benzoylcharaciol and helioscopinolide A may provide potential therapeutic strategy for various neuroinflammatory diseases. PMID:26683904

  1. Modulation of Hexadecyl-LPA-Mediated Activation of Mast Cells and Microglia by a Chemical Probe for LPA5.

    PubMed

    Kozian, Detlef H; von Haeften, Elisabeth; Joho, Sabrina; Czechtizky, Werngard; Anumala, Upendra R; Roux, Pascale; Dudda, Angela; Evers, Andreas; Nazare, Marc

    2016-05-01

    Mast cells and microglia play a critical role in innate immunity and inflammation and can be activated by a wide range of endogenous and exogenous stimuli. Lysophosphatidic acid (LPA) has recently been reported to activate mast cells and microglia. Using the human mast cell line HMC-1 and the mouse microglia cell line BV-2, we show that LPA-mediated activation can be prevented by blockade of the LPA receptor 5 (LPA5) in both cell lines. The identification of new LPA5-specific antagonists as tool compounds to probe and modulate the LPA5/LPA axis in relevant in vitro and in vivo assays should contribute to better understanding of the underlying role of LPAs in the development and progression of (neuro-) inflammatory diseases. PMID:26812365

  2. Anti-Inflammatory and Antioxidant Mechanism of Tangeretin in Activated Microglia.

    PubMed

    Lee, Yu Young; Lee, Eun-Jung; Park, Jin-Sun; Jang, Se-Eun; Kim, Dong-Hyun; Kim, Hee-Sun

    2016-06-01

    Tangeretin, a flavonoid from citrus fruit peels, has been proven to play an important role in anti-inflammatory responses and neuroprotective effects in several disease models, but further study is necessary for elucidating the detailed mechanisms of these effects. In this study, we examined the anti-inflammatory effect of tangeretin in lipopolysaccharide (LPS)-stimulated microglia. We first observed that tangeretin inhibited LPS-induced production of nitric oxide, tumor necrosis factor alpha, interleukin (IL)-6, and IL-1β, as well as LPS-induced mRNA expression of inducible nitric oxide synthases and cytokines. Additionally, we found that the activities, mRNA levels, and protein levels of matrix metalloproteinase (MMP)-3 and MMP-8 were inhibited, while the expression of tissue inhibitor of metalloproteinase-2 was enhanced by tangeretin in LPS-stimulated microglia. Further mechanistic study showed that tangeretin suppressed LPS-induced phosphorylation of mitogen-activated protein kinases and Akt. Also, tangeretin inhibited nuclear factor-κB by upregulating sirtuin 1 and 5'-adenosine monophosphate-activated protein kinase. We further demonstrated the antioxidant effect of tangeretin by showing that tangeretin inhibited reactive oxygen species production and p47(phox) phosphorylation, while enhancing the expression of heme oxygenase-1 and the DNA binding activity of nuclear factor-erythroid 2-related factor 2 to the antioxidant response element in LPS-stimulated microglia. Taken together, the results of the present study demonstrate that tangeretin possesses a potent anti-inflammatory and antioxidant effect in microglia. PMID:26899309

  3. Neuroinflammation and Depression: Microglia Activation, Extracellular Microvesicles and microRNA Dysregulation.

    PubMed

    Brites, Dora; Fernandes, Adelaide

    2015-01-01

    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 15-20 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 0.1-1 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 critical pathways associated with

  4. Neuroinflammation and Depression: Microglia Activation, Extracellular Microvesicles and microRNA Dysregulation

    PubMed Central

    Brites, Dora; Fernandes, Adelaide

    2015-01-01

    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 15–20 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 0.1–1 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 critical pathways associated with

  5. Microglia-derived TNFα induces apoptosis in neural precursor cells via transcriptional activation of the Bcl-2 family member Puma

    PubMed Central

    Guadagno, J; Xu, X; Karajgikar, M; Brown, A; Cregan, S P

    2013-01-01

    Neuroinflammation is a common feature of acute neurological conditions such as stroke and spinal cord injury, as well as neurodegenerative conditions such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. Previous studies have demonstrated that acute neuroinflammation can adversely affect the survival of neural precursor cells (NPCs) and thereby limit the capacity for regeneration and repair. However, the mechanisms by which neuroinflammatory processes induce NPC death remain unclear. Microglia are key mediators of neuroinflammation and when activated to induce a pro-inflammatory state produce a number of factors that could affect NPC survival. Importantly, in the present study we demonstrate that tumor necrosis factor α (TNFα) produced by lipopolysaccharide-activated microglia is necessary and sufficient to trigger apoptosis in mouse NPCs in vitro. Furthermore, we demonstrate that microglia-derived TNFα induces NPC apoptosis via a mitochondrial pathway regulated by the Bcl-2 family protein Bax. BH3-only proteins are known to play a key role in regulating Bax activation and we demonstrate that microglia-derived TNFα induces the expression of the BH3-only family member Puma in NPCs via an NF-κB-dependent mechanism. Specifically, we show that NF-κB is activated in NPCs treated with conditioned media from activated microglia and that Puma induction and NPC apoptosis is blocked by the NF-κB inhibitor BAY-117082. Importantly, we have determined that NPC apoptosis induced by activated microglia-derived TNFα is attenuated in Puma-deficient NPCs, indicating that Puma induction is required for NPC death. Consistent with this, we demonstrate that Puma-deficient NPCs exhibit an ∼13-fold increase in survival as compared with wild-type NPCs following transplantation into the inflammatory environment of the injured spinal cord in vivo. In summary, we have identified a key signaling pathway that regulates neuroinflammation induced apoptosis

  6. Microglia-derived TNFα induces apoptosis in neural precursor cells via transcriptional activation of the Bcl-2 family member Puma.

    PubMed

    Guadagno, J; Xu, X; Karajgikar, M; Brown, A; Cregan, S P

    2013-01-01

    Neuroinflammation is a common feature of acute neurological conditions such as stroke and spinal cord injury, as well as neurodegenerative conditions such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. Previous studies have demonstrated that acute neuroinflammation can adversely affect the survival of neural precursor cells (NPCs) and thereby limit the capacity for regeneration and repair. However, the mechanisms by which neuroinflammatory processes induce NPC death remain unclear. Microglia are key mediators of neuroinflammation and when activated to induce a pro-inflammatory state produce a number of factors that could affect NPC survival. Importantly, in the present study we demonstrate that tumor necrosis factor α (TNFα) produced by lipopolysaccharide-activated microglia is necessary and sufficient to trigger apoptosis in mouse NPCs in vitro. Furthermore, we demonstrate that microglia-derived TNFα induces NPC apoptosis via a mitochondrial pathway regulated by the Bcl-2 family protein Bax. BH3-only proteins are known to play a key role in regulating Bax activation and we demonstrate that microglia-derived TNFα induces the expression of the BH3-only family member Puma in NPCs via an NF-κB-dependent mechanism. Specifically, we show that NF-κB is activated in NPCs treated with conditioned media from activated microglia and that Puma induction and NPC apoptosis is blocked by the NF-κB inhibitor BAY-117082. Importantly, we have determined that NPC apoptosis induced by activated microglia-derived TNFα is attenuated in Puma-deficient NPCs, indicating that Puma induction is required for NPC death. Consistent with this, we demonstrate that Puma-deficient NPCs exhibit an ∼13-fold increase in survival as compared with wild-type NPCs following transplantation into the inflammatory environment of the injured spinal cord in vivo. In summary, we have identified a key signaling pathway that regulates neuroinflammation induced apoptosis

  7. An automated method to quantify microglia morphology and application to monitor activation state longitudinally in vivo.

    PubMed

    Kozlowski, Cleopatra; Weimer, Robby M

    2012-01-01

    Microglia are specialized immune cells of the brain. Upon insult, microglia initiate a cascade of cellular responses including a characteristic change in cell morphology. To study the dynamics of microglia immune response in situ, we developed an automated image analysis method that enables the quantitative assessment of microglia activation state within tissue based solely on cell morphology. Per cell morphometric analysis of fluorescently labeled microglia is achieved through local iterative threshold segmentation, which reduces errors caused by signal-to-noise variation across large volumes. We demonstrate, utilizing systemic application of lipopolysaccharide as a model of immune challenge, that several morphological parameters, including cell perimeter length, cell roundness and soma size, quantitatively distinguish resting versus activated populations of microglia within tissue comparable to traditional immunohistochemistry methods. Furthermore, we provide proof-of-concept data that monitoring soma size enables the longitudinal assessment of microglia activation in the mouse neocortex imaged via 2-photon in vivo microscopy. The ability to quantify microglia activation automatically by shape alone allows unbiased and rapid analysis of both fixed and in vivo central nervous system tissue. PMID:22457705

  8. RNF11 modulates microglia activation through NF-κB signalling cascade

    PubMed Central

    Dalal, Nirjari V.; Pranski, Elaine L.; Tansey, Malu G.; Lah, James J.; Levey, Allan I.; Betarbet, Ranjita S.

    2012-01-01

    Microglia are resident macrophages in the central nervous system (CNS) that play a major role in neuroinflammation and pathogenesis of several neurodegenerative diseases. Upon activation, microglia releases a multitude of pro-inflammatory factors that initiate and sustain an inflammatory response by activating various signalling pathways, including the NF-κB pathway in a feed forward cycle. In microglial cells, activation of NF-κB signalling is normally transient, while sustained NF-κB activation is associated with persistent neuroinflammation. RING finger protein 11 (RNF11), in association with A20 ubiquitin-editing complex, is one of the key negative regulators of NF-κB signalling pathway in neurons. In this study, we have demonstrated and confirmed this role of RNF11 in microglia, the immune cells of the CNS. Coimmunoprecipitation experiments showed that RNF11 and A20 interact in a microglial cell line, suggesting the presence of A20 ubiquitin-editing protein complex in microglial cells. Next, using targeted short hairpin RNA (shRNA) knockdown and over-expression of RNF11, we established that RNF11 expression levels are inversely related to NF-κB activation, as evident from altered expression of NF-κB transcribed genes. Moreover our studies, illustrated that RNF11 confers protection against LPS-induced cell cytotoxicity. Thus our investigations clearly demonstrated that microglial RNF11 is a negative regulator of NF-κB signalling pathway and could be a strong potential target for modulating inflammatory responses in neurodegenerative diseases. PMID:22975135

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

    PubMed

    Liu, Ming-Chao; Liu, Xin-Qin; Wang, Wen; Shen, Xue-Feng; Che, Hong-Lei; Guo, Yan-Yan; Zhao, Ming-Gao; Chen, Jing-Yuan; Luo, Wen-Jing

    2012-01-01

    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. PMID:22952811

  10. P2Y12 expression and function in alternatively activated human microglia

    PubMed Central

    Ase, Ariel R.; Kinsara, Angham; Rao, Vijayaraghava T.S.; Michell-Robinson, Mackenzie; Leong, Soo Yuen; Butovsky, Oleg; Ludwin, Samuel K.; Séguéla, Philippe; Bar-Or, Amit; Antel, Jack P.

    2015-01-01

    Objective: To investigate and measure the functional significance of altered P2Y12 expression in the context of human microglia activation. Methods: We performed in vitro and in situ experiments to measure how P2Y12 expression can influence disease-relevant functional properties of classically activated (M1) and alternatively activated (M2) human microglia in the inflamed brain. Results: We demonstrated that compared to resting and classically activated (M1) human microglia, P2Y12 expression is increased under alternatively activated (M2) conditions. In response to ADP, the endogenous ligand of P2Y12, M2 microglia have increased ligand-mediated calcium responses, which are blocked by selective P2Y12 antagonism. P2Y12 antagonism was also shown to decrease migratory and inflammatory responses in human microglia upon exposure to nucleotides that are released during CNS injury; no effects were observed in human monocytes or macrophages. In situ experiments confirm that P2Y12 is selectively expressed on human microglia and elevated under neuropathologic conditions that promote Th2 responses, such as parasitic CNS infection. Conclusion: These findings provide insight into the roles of M2 microglia in the context of neuroinflammation and suggest a mechanism to selectively target a functionally unique population of myeloid cells in the CNS. PMID:25821842

  11. Presenilin 2 influences miR146 level and activity in microglia

    PubMed Central

    Jayadev, Suman; Case, Amanda; Alajajian, Betty; Eastman, Alison J.; Möller, Thomas; Garden, Gwenn A.

    2014-01-01

    Microglia, the resident innate immune cells of the CNS, are the primary defenders against microbes and critical to CNS remodeling. Dysregulation of microglial behavior can lead to unchecked pro-inflammatory activity and subsequent neurodegeneration. The molecular mechanisms leading to chronic inflammation and microglial dysfunction in neurodegenerative diseases are not well-understood. It is known that patients with Presenilin 2 (PS2) mutations develop autosomal dominant Alzheimer disease. We have shown that a lack of normal PS2 function is associated with exaggerated microglia pro-inflammatory responses in vitro. To identify pathways by which PS2 regulates microglia and determine how PS2 dysfunction may lead to altered inflammatory pathways, we pursued an unbiased array approach to assess differential expression of microRNAs between murine PS2 knockout (KO) and wild-type microglia. We identified miR146, a negative regulator of monocyte pro-inflammatory response, as constitutively down-regulated in PS2 KO microglia. Consistent with a state of miR146 suppression, we found that PS2 KO microglia express higher levels of the miR146 target protein interleukin-1 receptor-associated kinase-1, and have increased NFκB transcriptional activity. We hypothesize that PS2 impacts microglial responses through modulation of miR146a. PS2 dysfunction, through aging or mutation, may contribute to neurodegeneration by influencing the pro-inflammatory behavior of microglia. PMID:23952003

  12. Manganese exposure induces microglia activation and dystrophy in the substantia nigra of non-human primates

    PubMed Central

    Verina, Tatyana; Kiihl, Samara F; Schneider, Jay S; Guilarte, Tomás R

    2011-01-01

    Chronic manganese (Mn) exposure produces neurological deficits including a form of parkinsonism that is different from Parkinson's disease (PD). In chronic Mn exposure, dopamine neurons in the substantia nigra (SN) do not degenerate but they appear to be dysfunctional. Further, previous studies have suggested that the substantia nigra pars reticulata (SNr) is affected by Mn. In the present study, we investigated whether chronic Mn exposure induces microglia activation in the substantia nigra pars compacta (SNc) and SNr in Cynomolgus macaques. Animals were exposed to different weekly doses of Mn (3.3–5.0, 5.0-6.7, 8.3-10 mg Mn/kg body weight) and microglia were examined in the substantia nigra using LN3 immunohistochemistry. We observed that in control animals, LN3 labeled microglia were characterized by a resting phenotype. However, in Mn-treated animals, microglia increased in number and displayed reactive changes with increasing Mn exposure. This effect was more prominent in the SNr than in the SNc. In the SNr of animals administered the highest Mn dose, microglia activation was the most advanced and included dystrophic changes. Reactive microglia expressed increased iNOS, L-ferritin, and intracellular ferric iron which were particularly prominent in dystrophic compartments. Our observations indicate that moderate Mn exposure produces structural changes on microglia, which may have significant consequences on their function. PMID:21112353

  13. Rapidly activated epidermal growth factor receptor mediates lipopolysaccharide-triggered migration of microglia.

    PubMed

    Qu, Wen-Sheng; Liu, Jun-Li; Li, Chun-Yu; Li, Xiao; Xie, Min-Jie; Wang, Wei; Tian, Dai-Shi

    2015-11-01

    Previous reports have suggested that epidermal growth factor receptor (EGFR) is involved in microglia activation characterized by cell morphology changes, cytokine production and cell migration; and the biochemical regulation of the microglia migration is a potential therapeutic target following CNS inflammatory damages. However, the role of EGFR in microglia motility after inflammatory stimulation remains unknown. In the present study, lipopolysaccharide (LPS) was found to trigger rapid EGFR phosphorylation within 10 min, which was sustained during long-term stimulation in both primary microglial cells and the cultured BV2 microglial cells, furthermore, blocking EGFR phosphorylation by AG1478 significantly attenuated the LPS-induced chemotactic and chemokinetic migration of microglia. In addition, LPS could initiate calcium oscillation in microglia during live-cell recording, however, an intracellular calcium chelator and a selective inhibitor of calcium/calmodulin-dependent protein kinase II, but not an extracellular calcium chelator, remarkably suppressed the LPS-induced EGFR phosphorylation in BV2 microglia cells. As EGFR is not a traditional receptor for LPS, these findings suggest that the rapid phosphorylation of EGFR is attributed to the LPS-triggered intracellular calcium mobilization. By examining the downstream signals of EGFR, we further proved that extracellular signal-regulated kinase (ERK) is essential for EGFR-mediated microglia migration, because ERK inhibition attenuated the chemotactic and chemokinetic migration of microglia that had been induced by either LPS or EGF. Collectively, these results suggest that LPS could trigger the rapid phosphorylation of EGFR and subsequent ERK activation through mobilizing calcium activity, which underlies the microglia migration in an inflammatory condition. PMID:26209152

  14. Vitamin D3 alters microglia immune activation by an IL-10 dependent SOCS3 mechanism.

    PubMed

    Boontanrart, Mandy; Hall, Samuel D; Spanier, Justin A; Hayes, Colleen E; Olson, Julie K

    2016-03-15

    Microglia become activated immune cells during infection or disease in the central nervous system (CNS). However, the mechanisms that downregulate activated microglia to prevent immune-mediated damage are not completely understood. Vitamin D3 has been suggested to have immunomodulatory affects, and high levels of vitamin D3 have been correlated with a decreased risk for developing some neurological diseases. Recent studies have demonstrated the synthesis of active vitamin D3, 1,25-dihydroxyvitamin D3, within the CNS, but its cellular source and neuroprotective actions remain unknown. Therefore, we wanted to determine whether microglia can respond to vitamin D3 and whether vitamin D3 alters immune activation of microglia. We have previously shown that microglia become activated by IFNγ or LPS or by infection with virus to express pro-inflammatory cytokines, chemokines, and effector molecules. In this study, activated microglia increased the expression of the vitamin D receptor and Cyp27b1, which encodes the enzyme for converting vitamin D3 into its active form, thereby enhancing their responsiveness to vitamin D3. Most importantly, the activated microglia exposed to vitamin D3 had reduced expression of pro-inflammatory cytokines, IL-6, IL-12, and TNFα, and increased expression of IL-10. The reduction in pro-inflammatory cytokines was dependent on IL-10 induction of suppressor of cytokine signaling-3 (SOCS3). Therefore, vitamin D3 increases the expression of IL-10 creating a feedback loop via SOCS3 that downregulates the pro-inflammatory immune response by activated microglia which would likewise prevent immune mediated damage in the CNS. PMID:26943970

  15. Minocycline, a tetracycline derivative, is neuroprotective against excitotoxicity by inhibiting activation and proliferation of microglia.

    PubMed

    Tikka, T; Fiebich, B L; Goldsteins, G; Keinanen, R; Koistinaho, J

    2001-04-15

    Minocycline, a semisynthetic tetracycline derivative, protects brain against global and focal ischemia in rodents. We examined whether minocycline reduces excitotoxicity in primary neuronal cultures. Minocycline (0.02 microm) significantly increased neuronal survival in mixed spinal cord (SC) cultures treated with 500 microm glutamate or 100 microm kainate for 24 hr. Treatment with these excitotoxins induced a dose-dependent proliferation of microglia that was associated with increased release of interleukin-1beta (IL-1beta) and was followed by increased lactate dehydrogenase (LDH) release. The excitotoxicity was enhanced when microglial cells were cultured on top of SC cultures. Minocycline prevented excitotoxin-induced microglial proliferation and the increased release of nitric oxide (NO) metabolites and IL-1beta. Excitotoxins induced microglial proliferation and increased the release of NO metabolites and IL-1beta also in pure microglia cultures, and these responses were inhibited by minocycline. In both SC and pure microglia cultures, excitotoxins activated p38 mitogen-activated protein kinase (p38 MAPK) exclusively in microglia. Minocycline inhibited p38 MAPK activation in SC cultures, and treatment with SB203580, a p38 MAPK inhibitor, but not with PD98059, a p44/42 MAPK inhibitor, increased neuronal survival. In pure microglia cultures, glutamate induced transient activation of p38 MAPK, and this was inhibited by minocycline. These findings indicate that the proliferation and activation of microglia contributes to excitotoxicity, which is inhibited by minocycline, an antibiotic used in severe human infections. PMID:11306611

  16. Neuromelanin activates microglia and induces degeneration of dopaminergic neurons: implications for progression of Parkinson's disease

    PubMed Central

    Zhang, Wei; Phillips, Kester; Wielgus, Albert R.; Liu, Jie; Albertini, Alberto; Zucca, Fabio A.; Faust, Rudolph; Qian, Steven Y.; Miller, David S.; Chignell, Colin F.; Wilson, Belinda; Jackson-Lewis, Vernice; Przedborski, Serge; Joset, Danielle; Loike, John; Hong, Jau-Shyong; Sulzer, David; Zecca, Luigi

    2013-01-01

    In Parkinson's disease (PD), there is a progressive loss of neuromelanin (NM)-containing dopamine (DA) neurons in substantia nigra (SN) which is associated with microgliosis and presence of extracellular NM. Herein, we have investigated the interplay between microglia and human NM on the degeneration of SN dopaminergic neurons. Although NM particles are phagocytised and degraded by microglia within minutes in vitro, extracellular NM particles induce microglial activation and ensuing production of superoxide, nitric oxide (NO), hydrogen peroxide (H2O2), and pro-inflammatory factors. Furthermore, NM produces, in a microglia-depended manner, neurodegeneration in primary ventral midbrain cultures. Neurodegeneration was effectively attenuated with microglia derived from mice deficient in macrophage antigen complex-1 (Mac-1), a microglial integrin receptor involved in the initiation of phagocytosis. Neuronal loss was also attenuated with microglia derived from mice deficient in phagocytic oxidase (PHOX), a subunit of NADPH oxidase, that is responsible for superoxide and H2O2 production, or apocyanin, a NADPH oxidase inhibitor. In vivo, NM injected into rat SN produces microgliosis and a loss of tyrosine hydroxylase (TH) neurons. Thus, these results show that extracellular NM can activate microglia, which in turn, may induce dopaminergic neurodegeneration in PD. Our study may have far-reaching implications, both pathogenic and therapeutic. PMID:19957214

  17. Granulocyte colony-stimulating factor improves alternative activation of microglia under microenvironment of spinal cord injury.

    PubMed

    Guo, Y; Zhang, H; Yang, J; Liu, S; Bing, L; Gao, J; Hao, A

    2013-05-15

    Granulocyte colony-stimulating factor (G-CSF) was investigated in the present study to examine whether it could affect the activation status of microglia under microenvironment of spinal cord injury and provide a potential therapeutic treatment for spinal cord injury. We established mouse spinal cord hemisection model and injected recombinant human G-CSF (rhG-CSF) subcutaneously. The results demonstrated that G-CSF could recruit microglia to the injury site in the first 72h after spinal cord injury. Moreover, G-CSF inhibits the expression of pro-inflammatory factors and promotes the expression of neurotrophic factors. Additionally, G-CSF also increases the expression of markers of M2 macrophage and inhibits the expression of markers of M1 macrophage in BV2 microglia in vitro model, favoring the M2 polarization of microglia under the microenvironment of spinal cord hemisection. NFκB signal pathway was involved in G-CSF-induced polarization of BV2 microglia. As a conclusion, we suggested that administration of G-CSF within the first 72h after spinal cord injury might reduce early inflammation-induced detrimental effect and promote an anti-inflammatory response that favors repair via improving alternative activation of microglia. Administration of G-CSF in the acute phase of spinal cord injury may be a promising strategy in restorative therapy after spinal cord injury. PMID:23419550

  18. Bipolar/rod-shaped microglia are proliferating microglia with distinct M1/M2 phenotypes.

    PubMed

    Tam, Wing Yip; Ma, Chi Him Eddie

    2014-01-01

    Microglia are generally considered the resident immune cells in the central nervous system (CNS) that regulate the primary events of neuroinflammatory responses. Microglia also play key roles in repair and neurodegeneration of the CNS after injury. Recent studies showed that trains of bipolar/rod-shaped microglia align end-to-end along the CNS injury site during the initial recovery phase. However, the cellular characteristics of bipolar/rod-shaped microglia remain largely unknown. Here, we established a highly reproducible in vitro culture model system to enrich and characterize bipolar/rod-shaped microglia by simply generating multiple scratches on a poly-d-lysine/laminin-coated culture dish. Trains of bipolar/rod-shaped microglia formed and aligned along the scratches in a manner that morphologically resembled microglial trains observed in injured brain. These bipolar/rod-shaped microglia were highly proliferative and expressed various M1/M2 markers. Further analysis revealed that these bipolar/rod-shaped microglia quickly transformed into amoeboid microglia within 30 minutes of lipopolysaccharide treatment, leading to the upregulation of pro-inflammatory cytokine gene expression and the activation of Jak/Stat. In summary, our culture system provides a model to further characterize this highly dynamic cell type. We suggest that bipolar/rod-shaped microglia are crucial for repairing the damaged CNS and that the molecular mechanisms underlying their morphological changes may serve as therapeutic biomarkers. PMID:25452009

  19. Stimulation of the NADPH oxidase in activated rat microglia removes nitric oxide but induces peroxynitrite production.

    PubMed

    Bal-Price, Anna; Matthias, Anita; Brown, Guy C

    2002-01-01

    Cultured rat microglia produced extracellular superoxide at a rate of 814 +/- 52 pmol/min/million cells when stimulated with phorbol 12-myristate 13-acetate (PMA) as measured by extracellular cytochrome c reduction. This superoxide production resulted in a rapid rate of superoxide dismutase-sensitive nitric oxide (NO) breakdown (155 +/- 30 pmol of NO/min/million cells) when NO was added to PMA stimulated microglia. Lipopolysaccharide/interferon-gamma (LPS/IFN-gamma)-activated microglia produce NO at the rate of 145 +/- 42 pmol/min/million cells and activated astrocytes at the rate of 51 +/- 9 pmol/min/million cells as estimated by NO electrode. Both types of cells maintained a steady-state level of 0.5-0.7 microm NO, only in the presence of L-arginine. Addition of PMA to activated microglia (but not activated astrocytes) caused the rapid and complete disappearance of all extracellular NO (but was restored in the presence of superoxide dismutase) followed by the production of peroxynitrite (as measured by urate-sensitive oxidation of dihydrorhodamine). Co-incubation of activated microglia with cerebellar granule neurones resulted in NO inhibition of neuronal respiration, but this was rapidly removed by PMA-induced breakdown of the NO. Thus, microglial NADPH oxidase can regulate the bioavailability of NO and the production of peroxynitrite. PMID:11796745

  20. Inhibition of Microglia Activation as a Phenotypic Assay in Early Drug Discovery

    PubMed Central

    Figuera-Losada, Mariana; Rojas, Camilo; Slusher, Barbara S.

    2014-01-01

    Complex biological processes such as inflammation, cell death, migration, proliferation, and the release of biologically active molecules can be used as outcomes in phenotypic assays during early stages of drug discovery. Although target-based approaches have been widely used over the past decades, a disproportionate number of first-in-class drugs have been identified using phenotypic screening. This review details phenotypic assays based on inhibition of microglial activation and their utility in primary and secondary screening, target validation, and pathway elucidation. The role of microglia, both in normal as well as in pathological conditions such as chronic neurodegenerative diseases, is reviewed. Methodologies to assess microglia activation in vitro are discussed in detail, and classes of therapeutic drugs known to decrease the proinflammatory and cytotoxic responses of activated microglia are appraised, including inhibitors of glutaminase, cystine/glutamate antiporter, nuclear factor κB, and mitogen-activated protein kinases. PMID:23945875

  1. Experimental autoimmune neuritis induces differential microglia activation in the rat spinal cord.

    PubMed

    Beiter, Thomas; Artelt, Matthias R; Trautmann, Katrin; Schluesener, Hermann J

    2005-03-01

    The reactive spatial and temporal activation pattern of parenchymal spinal cord microglia was analyzed in rat experimental autoimmune neuritis (EAN). We observed a differential activation of spinal cord microglial cells. A significant increase in ED1(+) microglia predominantly located in the dorsal horn grey matter of lumbar and thoracic spinal cord levels was observed on Day 12. As revealed by morphological criteria and by staining with further activation markers [allograft inflammatory factor 1 (AIF-1), EMAPII, OX6, P2X(4)R], reactive microglia did not reach a macrophage-like state of full activation. On Day 12, a significant proliferative response could be observed, affecting all spinal cord areas and including ED1(+) microglial cells and a wide range of putative progenitor cells. Thus, in rat EAN, a reactive localized and distinct microglial activation correlating with a generalized proliferative response could be observed. PMID:15710454

  2. Migration and Phagocytic Ability of Activated Microglia During Post-natal Development is Mediated by Calcium-Dependent Purinergic Signalling.

    PubMed

    Sunkaria, Aditya; Bhardwaj, Supriya; Halder, Avishek; Yadav, Aarti; Sandhir, Rajat

    2016-03-01

    Microglia play an important role in synaptic pruning and controlled phagocytosis of neuronal cells during developmental stages. However, the mechanisms that regulate these functions are not completely understood. The present study was designed to investigate the role of purinergic signalling in microglial migration and phagocytic activity during post-natal brain development. One-day-old BALB/c mice received lipopolysaccharide (LPS) and/or a purinergic analogue (2-methylthioladenosine-5'-diphosphate; 2MeSADP), intracerebroventrically (i.c.v.). Combined administration of LPS and 2MeSADP resulted in activation of microglia as evident from increased expression of ionised calcium-binding adapter molecule 1 (Iba1). Activated microglia showed increased expression of purinergic receptors (P2Y2, P2Y6 and P2Y12). LPS either alone or in combination with 2MeSADP induced the expression of Na(+)/Ca(2+) exchanger (NCX-1) and P/Q-type Ca(2+) channels along with MARCKS-related protein (MRP), which is an integral component of cell migration machinery. In addition, LPS and 2MeSADP administration induced the expression of microglial CD11b and DAP12 (DNAX-activation protein 12), which are known to be involved in phagocytosis of neurons during development. Interestingly, administration of thapsigargin (TG), a specific Ca(2+)-ATPase inhibitor of endoplasmic reticulum, prevented the LPS/2MeSADP-induced microglial activation and migration by down-regulating the expression of Iba1 and MRP, respectively. Moreover, TG also reduced the LPS/2MeSADP-induced expression of CD11b/DAP12. Taken together, the findings reveal for the first time that Ca(2+)-mediated purinergic receptors regulate the migration and phagocytic ability of microglia during post-natal brain development. PMID:25575683

  3. Activation of p38 signaling in the microglia in the nucleus accumbens contributes to the acquisition and maintenance of morphine-induced conditioned place preference.

    PubMed

    Zhang, Xue-Qin; Cui, Yu; Cui, Yue; Chen, Yu; Na, Xiao-Dong; Chen, Feng-Ying; Wei, Xu-Hong; Li, Yong-Yong; Liu, Xian-Guo; Xin, Wen-Jun

    2012-02-01

    Several lines of evidence have suggested that activated glia contributes to morphine-induced reward (conditioned place preference, CPP). Compared to well-defined roles of astrocyte in morphine CPP, the role of microglia in the nucleus accumbens (NAc) remains poorly characterized. The aim of the present study was to investigate the distinct role of microglia in morphine-induced CPP. Systemic administration of morphine (7.5 mg/kg for 5 days) induced significant preference for the morphine-paired compartment in rats, which lasted for at least 6 days after cessation of morphine treatment. Immunohistochemistry results showed that activation of p38 in the NAc microglia induced by chronic morphine treatment maintained on day 11. Bilateral intra-NAc injection of minocycline, a putative microglia inhibitor, or SB203580, an inhibitor of p38, prior to morphine administration not only inhibited p38 activation in the microglia but impaired the acquisition of CPP. On the day following the acquisition of morphine CPP, a single injection of minocycline or SB203580 failed to block the expression of CPP. Notably, pretreatment with minocycline or SB203580 for 5 days following the acquisition of morphine CPP significantly suppressed the activation of p38 and attenuated the maintenance of morphine CPP. Collectively, our present study indicates that the p38 signaling in the NAc microglia may play an important role in the acquisition and maintenance but not the expression of morphine CPP, and provides new evidence that microglia might be a potential target for the therapy of morphine addiction. PMID:22004988

  4. Aspirin-Triggered Lipoxin A4 Stimulates Alternative Activation of Microglia and Reduces Alzheimer Disease–Like Pathology in Mice

    PubMed Central

    Medeiros, Rodrigo; Kitazawa, Masashi; Passos, Giselle F.; Baglietto-Vargas, David; Cheng, David; Cribbs, David H.; LaFerla, Frank M.

    2014-01-01

    Microglia play an essential role in innate immunity, homeostasis, and neurotropic support in the central nervous system. In Alzheimer disease (AD), these cells may affect disease progression by modulating the buildup of β-amyloid (Aβ) or releasing proinflammatory cytokines and neurotoxic substances. Discovering agents capable of increasing Aβ uptake by phagocytic cells is of potential therapeutic interest for AD. Lipoxin A4 (LXA4) is an endogenous lipid mediator with potent anti-inflammatory properties directly involved in inflammatory resolution, an active process essential for appropriate host responses, tissue protection, and the return to homeostasis. Herein, we demonstrate that aspirin-triggered LXA4 (15 μg/kg) s.c., twice a day, reduced NF-κB activation and levels of proinflammatory cytokines and chemokines, as well as increased levels of anti-inflammatory IL-10 and transforming growth factor-β. Such changes in the cerebral milieu resulted in recruitment of microglia in an alternative phenotype, as characterized by the up-regulation of YM1 and arginase-1 and the down-regulation of inducible nitric oxide synthase expression. Microglia in an alternative phenotype–positive cells demonstrated improved phagocytic function, promoting clearance of Aβ deposits and ultimately leading to reduction in synaptotoxicity and improvement in cognition. Our data indicate that activating LXA4 signaling may represent a novel therapeutic approach for AD. PMID:23506847

  5. Cerebral microglia activation in hepatitis C virus infection correlates to cognitive dysfunction.

    PubMed

    Pflugrad, H; Meyer, G-J; Dirks, M; Raab, P; Tryc, A B; Goldbecker, A; Worthmann, H; Wilke, F; Boellaard, R; Yaqub, M; Berding, G; Weissenborn, K

    2016-05-01

    Hepatitis C virus (HCV) infection may induce chronic fatigue and cognitive dysfunction. Virus replication was proven within the brain and HCV-positive cells were identified as microglia and astrocytes. We hypothesized that cerebral dysfunction in HCV-afflicted patients is associated with microglia activation. Microglia activation was assessed in vivo in 22 patients with chronic HCV infection compared to six healthy controls using [(11) C]-PK11195 Positron Emission Tomography (PET) combined with magnetic resonance tomography for anatomical localization. Patients were subdivided with regard to their PCR status, Fatigue Impact Scale score (FIS) and attention test sum score (ATS). A total of 12 patients (54.5%) were HCV PCR positive [of which 7 (58.3%) had an abnormal FIS and 7 (58.3%) an abnormal ATS], 10 patients (45.5%) were HCV PCR negative (5 (50%) each with an abnormal FIS or ATS). Patients without attention deficits showed a significantly higher accumulation of [(11) C]-PK11195 in the putamen (P = 0.05), caudate nucleus (P = 0.03) and thalamus (P = 0.04) compared to controls. Patients with and without fatigue did not differ significantly with regard to their specific tracer binding in positron emission tomography. Preserved cognitive function was associated with significantly increased microglia activation with predominance in the basal ganglia. This indicates a probably neuroprotective effect of microglia activation in HCV-infected patients. PMID:26768955

  6. Activated microglia cause reversible apoptosis of pheochromocytoma cells, inducing their cell death by phagocytosis

    PubMed Central

    Hornik, Tamara C.; Vilalta, Anna; Brown, Guy C.

    2016-01-01

    ABSTRACT Some apoptotic processes, such as phosphatidylserine exposure, are potentially reversible and do not necessarily lead to cell death. However, phosphatidylserine exposure can induce phagocytosis of a cell, resulting in cell death by phagocytosis: phagoptosis. Phagoptosis of neurons by microglia might contribute to neuropathology, whereas phagoptosis of tumour cells by macrophages might limit cancer. Here, we examined the mechanisms by which BV-2 microglia killed co-cultured pheochromocytoma (PC12) cells that were either undifferentiated or differentiated into neuronal cells. We found that microglia activated by lipopolysaccharide rapidly phagocytosed PC12 cells. Activated microglia caused reversible phosphatidylserine exposure on and reversible caspase activation in PC12 cells, and caspase inhibition prevented phosphatidylserine exposur and decreased subsequent phagocytosis. Nitric oxide was necessary and sufficient to induce the reversible phosphatidylserine exposure and phagocytosis. The PC12 cells were not dead at the time they were phagocytised, and inhibition of their phagocytosis left viable cells. Cell loss was inhibited by blocking phagocytosis mediated by phosphatidylserine, MFG-E8, vitronectin receptors or P2Y6 receptors. Thus, activated microglia can induce reversible apoptosis of target cells, which is insufficient to cause apoptotic cell death, but sufficient to induce their phagocytosis and therefore cell death by phagoptosis. PMID:26567213

  7. 17β-estradiol attenuates injury-induced microglia activation in the oculomotor nucleus.

    PubMed

    Gyenes, A; Hoyk, Z; Csakvari, E; Siklos, L; Parducz, A

    2010-12-15

    Recent studies provide increasing data indicating the prominent role of estrogens in protecting the nervous system against the noxious consequences of nerve injury. It is also clear that in the process of nerve injury and recovery not only the neurons, but the glial cells are also involved and they are important components of the protective mechanisms. In the present article the effect of 17β-estradiol on injury-induced microglia activation was studied in an animal model. Peripheral axotomy of the oculomotor neurons was achieved by the removal of the right eyeball including the extraocular muscles of ovariectomized adult mice. The time course and the extent of microglia activation was followed by the unbiased morphometric analysis of CD11b immunoreactive structures within the oculomotor nucleus. The first sign of microglia activation appeared after 24 h following injury, the maximal effect was found on the fourth day. In ovariectomized females hormone treatment (daily injection of 17β-estradiol, 5 μg/100 g b.w.) decreased significantly the microglia reaction at postoperative day 4. Our results show that microglia response to nerve injury is affected by estradiol, that is these cells may mediate some of the hormonal effects and may contribute to protective mechanisms resulting in the structural and functional recovery of the nervous system. PMID:20870014

  8. Two Faces of Chondroitin Sulfate Proteoglycan in Spinal Cord Repair: A Role in Microglia/Macrophage Activation

    PubMed Central

    London, Anat; Segev, Yifat; Jacob-Hirsch, Jasmin; Amariglio, Ninette; Rechavi, Gidon; Schwartz, Michal

    2008-01-01

    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-α) 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 these cells

  9. The immune theory of psychiatric diseases: a key role for activated microglia and circulating monocytes.

    PubMed

    Beumer, Wouter; Gibney, Sinead M; Drexhage, Roosmarijn C; Pont-Lezica, Lorena; Doorduin, Janine; Klein, Hans C; Steiner, Johann; Connor, Thomas J; Harkin, Andrew; Versnel, Marjan A; Drexhage, Hemmo A

    2012-11-01

    This review describes a key role for mononuclear phagocytes in the pathogenesis of major psychiatric disorders. There is accumulating evidence for activation of microglia (histopathology and PET scans) and circulating monocytes (enhanced gene expression of immune genes, an overproduction of monocyte/macrophage-related cytokines) in patients with bipolar disorder, major depressive disorder, and schizophrenia. These data are strengthened by observations in animal models, such as the MIA models, the chronic stress models, and the NOD mouse model. In these animal models of depressive-, anxiety-, and schizophrenia-like behavior, similar activations of microglia and circulating monocytes can be found. These animal models also make in-depth pathogenic studies possible and show that microglia activation impacts neuronal development and function in brain areas congruent with the altered depressive and schizophrenia-like behaviors. PMID:22875882

  10. Linking Activation of Microglia and Peripheral Monocytic Cells to the Pathophysiology of Psychiatric Disorders

    PubMed Central

    Takahashi, Yuta; Yu, Zhiqian; Sakai, Mai; Tomita, Hiroaki

    2016-01-01

    A wide variety of studies have identified microglial activation in psychiatric disorders, such as schizophrenia, bipolar disorder, and major depressive disorder. Relatively fewer, but robust, studies have detected activation of peripheral monocytic cells in psychiatric disorders. Considering the origin of microglia, as well as neuropsychoimmune interactions in the context of the pathophysiology of psychiatric disorders, it is reasonable to speculate that microglia interact with peripheral monocytic cells in relevance with the pathogenesis of psychiatric disorders; however, these interactions have drawn little attention. In this review, we summarize findings relevant to activation of microglia and monocytic cells in psychiatric disorders, discuss the potential association between these cell types and disease pathogenesis, and propose perspectives for future research on these processes. PMID:27375431

  11. Microglia Activate Migration of Glioma Cells through a Pyk2 Intracellular Pathway

    PubMed Central

    Rolón-Reyes, Kimberleve; Kucheryavykh, Yuriy V.; Cubano, Luis A.; Inyushin, Mikhail; Skatchkov, Serguei N.; Eaton, Misty J.; Harrison, Jeffrey K.; Kucheryavykh, Lilia Y.

    2015-01-01

    Glioblastoma is one of the most aggressive and fatal brain cancers due to the highly invasive nature of glioma cells. Microglia infiltrate most glioma tumors and, therefore, make up an important component of the glioma microenvironment. In the tumor environment, microglia release factors that lead to the degradation of the extracellular matrix and stimulate signaling pathways to promote glioma cell invasion. In the present study, we demonstrated that microglia can promote glioma migration through a mechanism independent of extracellular matrix degradation. Using western blot analysis, we found upregulation of proline rich tyrosine kinase 2 (Pyk2) protein phosphorylated at Tyr579/580 in glioma cells treated with microglia conditioned medium. This upregulation occurred in rodent C6 and GL261 as well as in human glioma cell lines with varying levels of invasiveness (U-87MG, A172, and HS683). siRNA knock-down of Pyk2 protein and pharmacological blockade by the Pyk2/focal-adhesion kinase (FAK) inhibitor PF-562,271 reversed the stimulatory effect of microglia on glioma migration in all cell lines. A lower concentration of PF-562,271 that selectively inhibits FAK, but not Pyk2, did not have any effect on glioma cell migration. Moreover, with the use of the CD11b-HSVTK microglia ablation mouse model we demonstrated that elimination of microglia in the implanted tumors (GL261 glioma cells were used for brain implantation) by the local in-tumor administration of Ganciclovir, significantly reduced the phosphorylation of Pyk2 at Tyr579/580 in implanted tumor cells. Taken together, these data indicate that microglial cells activate glioma cell migration/dispersal through the pro-migratory Pyk2 signaling pathway in glioma cells. PMID:26098895

  12. Microglia Activate Migration of Glioma Cells through a Pyk2 Intracellular Pathway.

    PubMed

    Rolón-Reyes, Kimberleve; Kucheryavykh, Yuriy V; Cubano, Luis A; Inyushin, Mikhail; Skatchkov, Serguei N; Eaton, Misty J; Harrison, Jeffrey K; Kucheryavykh, Lilia Y

    2015-01-01

    Glioblastoma is one of the most aggressive and fatal brain cancers due to the highly invasive nature of glioma cells. Microglia infiltrate most glioma tumors and, therefore, make up an important component of the glioma microenvironment. In the tumor environment, microglia release factors that lead to the degradation of the extracellular matrix and stimulate signaling pathways to promote glioma cell invasion. In the present study, we demonstrated that microglia can promote glioma migration through a mechanism independent of extracellular matrix degradation. Using western blot analysis, we found upregulation of proline rich tyrosine kinase 2 (Pyk2) protein phosphorylated at Tyr579/580 in glioma cells treated with microglia conditioned medium. This upregulation occurred in rodent C6 and GL261 as well as in human glioma cell lines with varying levels of invasiveness (U-87MG, A172, and HS683). siRNA knock-down of Pyk2 protein and pharmacological blockade by the Pyk2/focal-adhesion kinase (FAK) inhibitor PF-562,271 reversed the stimulatory effect of microglia on glioma migration in all cell lines. A lower concentration of PF-562,271 that selectively inhibits FAK, but not Pyk2, did not have any effect on glioma cell migration. Moreover, with the use of the CD11b-HSVTK microglia ablation mouse model we demonstrated that elimination of microglia in the implanted tumors (GL261 glioma cells were used for brain implantation) by the local in-tumor administration of Ganciclovir, significantly reduced the phosphorylation of Pyk2 at Tyr579/580 in implanted tumor cells. Taken together, these data indicate that microglial cells activate glioma cell migration/dispersal through the pro-migratory Pyk2 signaling pathway in glioma cells. PMID:26098895

  13. Electromagnetic pulse activated brain microglia via the p38 MAPK pathway.

    PubMed

    Yang, Long-Long; Zhou, Yan; Tian, Wei-Dong; Li, Hai-Juan; Kang-Chu-Li; Miao, Xia; An, Guang-Zhou; Wang, Xiao-Wu; Guo, Guo-Zhen; Ding, Gui-Rong

    2016-01-01

    Previously, we found that electromagnetic pulses (EMP) induced an increase in blood brain barrier permeability and the leakage of albumin from blood into brain tissue. Albumin is known to activate microglia cells. Thus, we hypothesised that microglia activation could occur in the brain after EMP exposure. To test this hypothesis, the morphology and secretory function of microglia cells, including the expression of OX-42 (a marker of microglia activation), and levels of TNF-α, IL-10, IL-1β, and NO were determined in the rat cerebral cortex after EMP exposure. In addition, to examine the signalling pathway of EMP-induced microglia activation, protein and phosphorylated protein levels of p38, JNK and ERK were determined. It was found that the expression of OX-42increased significantly at 1, 6 and 12h (p<0.05) and recovered to the sham group level at 24h after EMP exposure. Levels of NO, TNF-α and IL-10 also changed significantly in vivo and in vitro after EMP exposure. The protein level of p38 and phosphorylated p38 increased significantly after EMP exposure (p<0.05) and recovered to sham levels at 12 and 24h, respectively. Protein and phosphorylated protein levels of ERK and JNK did not change. SB203580 (p38 inhibitor) partly prevented the change in NO, IL-10, IL-1β, TNF-α levels induced by EMP exposure. Taken together, these results suggested that EMP exposure (200kV/m, 200 pulses) could activate microglia in rat brain and affect its secretory function both in vivo and in vitro, and the p38 pathway is involved in this process. PMID:26688329

  14. Kainic acid induces expression of caveolin-1 in activated microglia in rat brain.

    PubMed

    Takeuchi, Shigeko; Matsuda, Wakoto; Tooyama, Ikuo; Yasuhara, Osamu

    2013-01-01

    Caveolin-1, a major constituent of caveolae, has been implicated in endocytosis, signal transduction and cholesterol transport in a wide variety of cells. In the present study, the expression of caveolin-1 was examined by immunohistochemistry in rat brain with or without systemic injection of kainic acid (KA). Caveolin-1 immunoreactivity was observed in capillary walls in brains of control rats. From one to seven days after KA injection, caveolin-1 immunoreactivity appeared in activated microglia in the cerebral cortex, hippocampus and other brain regions. The strongest immunoreactivity of microglia was seen after 3 days after KA administration. The expression of caveolin-1 was confirmed by RT-PCR and Western blot analysis, respectively. The induction of caveolin-1 expression in microglia activated in response to kainic acid administration suggests its possible role in a modulation of inflammation. PMID:23690214

  15. Fluoride-Induced Neuron Apoptosis and Expressions of Inflammatory Factors by Activating Microglia in Rat Brain.

    PubMed

    Yan, Nan; Liu, Yan; Liu, Shengnan; Cao, Siqi; Wang, Fei; Wang, Zhengdong; Xi, Shuhua

    2016-09-01

    Excessive exposure to fluoride results in structural and functional damages to the central nervous system (CNS), and neurotoxicity of fluoride may be associated with neurodegenerative changes. Chronic microglial activation appears to cause neuronal damage through producing proinflammatory cytokines and is involved in many neurodegenerative disorders. It is not known about effects on microglia of fluoride. In the present study, healthy adult Wistar rats were exposed to 60 and 120 ppm fluoride in drinking water for 10 weeks, and control rats received deionized water. After 10 weeks, rats were sacrificed under anesthesia then apoptosis in neuron and inflammatory factors secreted by microglia were determined. We found that apoptosis of neurons in fluoride-treated rat brain increased and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive immunofluorescence increased with increasing fluoride concentrations. Bax protein expression increased and Bcl-2 protein expression decreased in fluoride-treated rat brain compared with that of the control rat brain. The microglia in the hippocampus and cortex of fluoride-treated rats were activated by immunostaining with OX-42, a marker of activated microglia, and OX-42-positive microglia cells were more abundant in the hippocampus than in the cortex. The levels of IL-1β and IL-6 protein expression in OX-42-labeled microglial cells were significantly increased in the cortex and hippocampus of rats exposed to fluoride, and TNF-α immunoreactivity in microglial cells of the hippocampus was significantly higher in the 120 ppm fluoride-treated group than that in the control group. Our results indicate that fluoride induced neuron apoptosis and expressions of inflammatory factors by activating microglia in rat brain. PMID:26253724

  16. Chronic caffeine ingestion causes microglia activation, but not proliferation in the healthy brain

    PubMed Central

    Steger, Rob; Kamal, Arifa; Lutchman, Sara; Intrabartolo, Liliana; Sohail, Rabia; Brumberg, Joshua C.

    2014-01-01

    Caffeine is the most popular psychoactive drug in the world which contributes to behavioral and metabolic changes when ingested. Within the central nervous system (CNS), caffeine has a high affinity for A1 and A2a adenosine receptors. Serving as an antagonist, caffeine affects the ability for adenosine to bind to these receptors. Caffeine has been shown to alter neuronal functioning through increasing spontaneous firing. However, the effects of caffeine on non-neuronal cells in the CNS has been not been studied extensively. Microglia are one phenotype of non-neuronal glia within the CNS. Acting as phagocytes, they contribute to the immune defense system of the brain and express A1 and A2a adenosine receptors. Caffeine, therefore, may affect microglia. In order to test this hypothesis, CD-1 mice were randomly placed into one of three groups: control, low caffeine (0.3g/L water) and high caffeine (1.0g/L water) and were allowed to drink freely for 30 days. Following 30 days, brain sections were stained to reveal microglia. Morphological reconstructions and density measurements were examined in cortical and subcortical areas including the primary sensory cortex, primary motor cortex and striatum. Results indicate that microglial density throughout the brain is decreased in the caffeine groups as compared to the control. Caffeine also impacted microglia morphology shortening process length and decreasing branching. These results suggest that chronic caffeine ingestion has a systemic impact on microglia density and their activation. PMID:24881873

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

    PubMed

    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. PMID:27339657

  18. Activated iron-containing microglia in the human hippocampus identified by magnetic resonance imaging in Alzheimer disease.

    PubMed

    Zeineh, Michael M; Chen, Yuanxin; Kitzler, Hagen H; Hammond, Robert; Vogel, Hannes; Rutt, Brian K

    2015-09-01

    Although amyloid plaques and neurofibrillary pathology play important roles in Alzheimer disease (AD), our understanding of AD is incomplete, and the contribution of microglia and iron to neurodegeneration is unknown. High-field magnetic resonance imaging (MRI) is exquisitely sensitive to microscopic iron. To explore iron-associated neuroinflammatory AD pathology, we studied AD and control human brain specimens by (1) performing ultra-high resolution ex vivo 7 Tesla MRI, (2) coregistering the MRI with successive histologic staining for iron, microglia, amyloid beta, and tau, and (3) quantifying the relationship between magnetic resonance signal intensity and histological staining. In AD, we identified numerous small MR hypointensities primarily within the subiculum that were best explained by the combination of microscopic iron and activated microglia (p = 0.025), in contradistinction to the relatively lesser contribution of tau or amyloid. Neuropathologically, this suggests that microglial-mediated neurodegeneration may occur in the hippocampal formation in AD and is detectable by ultra-high resolution MRI. PMID:26190634

  19. Activated iron-containing microglia in the human hippocampus identified by magnetic resonance imaging in Alzheimer disease

    PubMed Central

    Zeineh, Michael M.; Chen, Yuanxin; Kitzler, Hagen H.; Hammond, Robert; Vogel, Hannes; Rutt, Brian K.

    2016-01-01

    Although amyloid plaques and neurofibrillary pathology play important roles in Alzheimer disease (AD), our understanding of AD is incomplete, and the contribution of microglia and iron to neurodegeneration is unknown. High-field magnetic resonance imaging (MRI) is exquisitely sensitive to microscopic iron. To explore iron-associated neuroinflammatory AD pathology, we studied AD and control human brain specimens by (1) performing ultra-high resolution ex vivo 7 Tesla MRI, (2) coregistering the MRI with successive histologic staining for iron, microglia, amyloid beta, and tau, and (3) quantifying the relationship between magnetic resonance signal intensity and histological staining. In AD, we identified numerous small MR hypointensities primarily within the subiculum that were best explained by the combination of microscopic iron and activated microglia (p = 0.025), in contradistinction to the relatively lesser contribution of tau or amyloid. Neuropathologically, this suggests that microglial-mediated neurodegeneration may occur in the hippocampal formation in AD and is detectable by ultra-high resolution MRI. PMID:26190634

  20. AUTOTAXIN DOWNREGULATES LPS – INDUCED MICROGLIA ACTIVATION AND PRO-INFLAMMATORY CYTOKINES PRODUCTION

    PubMed Central

    Awada, Rana; Saulnier-Blache, Jean Sébastien; Grès, Sandra; Bourdon, Emmanuel; Rondeau, Philippe; Parimisetty, Avinash; Orihuela, Ruben; Harry, G. Jean; d’Hellencourt, Christian Lefebvre

    2014-01-01

    Inflammation is essential in defense against infection or injury. It is tightly regulated, as over-response can be detrimental, especially in immune-privileged organs such as the central nervous system (CNS). Microglia constitutes the major source of inflammatory factors, but are also involved in the regulation of the inflammation and in the reparation. Autotaxin (ATX), a phospholipase D, converts lysophosphatidylcholine into lysophosphatidic acid (LPA) and is upregulated in several CNS injuries. LPA, a pleiotropic immunomodulatory factor, can induce multiple cellular processes including morphological changes, proliferation, death and survival. We investigated ATX effects on microglia inflammatory response to lipopolysaccharide (LPS), mimicking gram-negative infection. Murine BV-2 microglia and stable transfected, overexpressing ATX-BV-2 (A+) microglia were treated with LPS. Tumor necrosis factor α (TNFα), interleukin (IL)-6 and IL-10 mRNA and proteins levels were examined by qRT-PCR and ELISA, respectively. Secreted LPA was quantified by a radioenzymatic assay and microglial activation markers (CD11b, CD14, B7.1 and B7.2) were determined by flow cytometry. ATX expression and LPA production were significantly enhanced in LPS treated BV-2 cells. LPS induction of mRNA and protein level for TNFα and IL-6 were inhibited in A+ cells, while IL-10 was increased. CD11b, CD14, and B7.1 and B7.2 expressions were reduced in A+ cells. Our results strongly suggest deactivation of microglia and an IL-10 inhibitory of ATX with LPS induced microglia activation. PMID:25053164

  1. Microglia activation regulates GluR1 phosphorylation in chronic unpredictable stress-induced cognitive dysfunction.

    PubMed

    Liu, Mingchao; Li, Juan; Dai, Peng; Zhao, Fang; Zheng, Gang; Jing, Jinfei; Wang, Jiye; Luo, Wenjing; Chen, Jingyuan

    2015-01-01

    Chronic stress is considered to be a major risk factor in the development of psychopathological syndromes in humans. Cognitive impairments and long-term potentiation (LTP) impairments are increasingly recognized as major components of depression, anxiety disorders and other stress-related chronic psychological illnesses. It seems timely to systematically study the potentially underlying neurobiological mechanisms of altered cognitive and synaptic plasticity in the course of chronic stress. In the present study, a rat model of chronic unpredictable stress (CUS) induced a cognitive impairment in spatial memory in the Morris water maze (MWM) test and a hippocampal LTP impairment. CUS also induced hippocampal microglial activation and attenuated phosphorylation of glutamate receptor 1 (GluR1 or GluA1). Moreover, chronic treatment with the selective microglial activation blocker, minocycline (120 mg/kg per day), beginning 3 d before CUS treatment and continuing through the behavioral testing period, prevented the CUS-induced impairments of spatial memory and LTP induction. Additional studies showed that minocycline-induced inhibition of microglia activation was associated with increased phosphorylation of GluR1. These results suggest that hippocampal microglial activation modulates the level of GluR1 phosphorylation and might play a causal role in CUS-induced cognitive and LTP disturbances. PMID:25472821

  2. Microglia activation as a biomarker for traumatic brain injury.

    PubMed

    Hernandez-Ontiveros, Diana G; Tajiri, Naoki; Acosta, Sandra; Giunta, Brian; Tan, Jun; Borlongan, Cesar V

    2013-01-01

    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. PMID:23531681

  3. Microglia Activation as a Biomarker for Traumatic Brain Injury

    PubMed Central

    Hernandez-Ontiveros, Diana G.; Tajiri, Naoki; Acosta, Sandra; Giunta, Brian; Tan, Jun; Borlongan, Cesar V.

    2013-01-01

    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. PMID:23531681

  4. Functionally Charged Polystyrene Particles Activate Immortalized Mouse Microglia (BV2): Cellular and Genomic Response

    EPA Science Inventory

    The effect of particle surface charge on the biological activation of immortalized mouse microglia (BV2) was examined. Same size (~850-950 nm) spherical polystyrene microparticles (SPM) with net negative (carboxyl, COOH-) or positive (dimethyl amino, CH3)2

  5. Transcranial Direct Current Stimulation Modulates Neurogenesis and Microglia Activation in the Mouse Brain

    PubMed Central

    Pikhovych, Anton; Stolberg, Nina Paloma; Jessica Flitsch, Lea; Walter, Helene Luise; Graf, Rudolf; Fink, Gereon Rudolf; Schroeter, Michael

    2016-01-01

    Transcranial direct current stimulation (tDCS) has been suggested as an adjuvant tool to promote recovery of function after stroke, but the mechanisms of its action to date remain poorly understood. Moreover, studies aimed at unraveling those mechanisms have essentially been limited to the rat, where tDCS activates resident microglia as well as endogenous neural stem cells. Here we studied the effects of tDCS on microglia activation and neurogenesis in the mouse brain. Male wild-type mice were subjected to multisession tDCS of either anodal or cathodal polarity; sham-stimulated mice served as control. Activated microglia in the cerebral cortex and neuroblasts generated in the subventricular zone as the major neural stem cell niche were assessed immunohistochemically. Multisession tDCS at a sublesional charge density led to a polarity-dependent downregulation of the constitutive expression of Iba1 by microglia in the mouse cortex. In contrast, both anodal and, to an even greater extent, cathodal tDCS induced neurogenesis from the subventricular zone. Data suggest that tDCS elicits its action through multifacetted mechanisms, including immunomodulation and neurogenesis, and thus support the idea of using tDCS to induce regeneration and to promote recovery of function. Furthermore, data suggest that the effects of tDCS may be animal- and polarity-specific. PMID:27403166

  6. Increased lysosomal biogenesis in activated microglia and exacerbated neuronal damage after traumatic brain injury in progranulin-deficient mice.

    PubMed

    Tanaka, Y; Matsuwaki, T; Yamanouchi, K; Nishihara, M

    2013-10-10

    Progranulin (PGRN) is known to play a role in the pathogenesis of neurodegenerative diseases. Recently, it has been demonstrated that patients with the homozygous mutation in the GRN gene present with neuronal ceroid lipofuscinosis, and there is growing evidence that PGRN is related to lysosomal function. In the present study, we investigated the possible role of PGRN in the lysosomes of activated microglia in the cerebral cortex after traumatic brain injury (TBI). We showed that the mouse GRN gene has two possible coordinated lysosomal expression and regulation (CLEAR) sequences that bind to transcription factor EB (TFEB), a master regulator of lysosomal genes. PGRN was colocalized with Lamp1, a lysosomal marker, and Lamp1-positive areas in GRN-deficient (KO) mice were significantly expanded compared with wild-type (WT) mice after TBI. Expression of all the lysosome-related genes examined in KO mice was significantly higher than that in WT mice. The number of activated microglia with TFEB localized to the nucleus was also significantly increased in KO as compared with WT mice. Since the TFEB translocation is regulated by the mammalian target of rapamycin complex 1 (mTORC1) activity in the lysosome, we compared ribosomal S6 kinase 1 (S6K1) phosphorylation that reflects mTORC1 activity. S6K1 phosphorylation in KO mice was significantly lower than that in WT mice. In addition, the number of nissl-positive and fluoro-jade B-positive cells around the injury was significantly decreased and increased, respectively, in KO as compared with WT mice. These results suggest that PGRN localized in the lysosome is involved in the activation of mTORC1, and its deficiency leads to increased TFEB nuclear translocation with a resultant increase in lysosomal biogenesis in activated microglia and exacerbated neuronal damage in the cerebral cortex after TBI. PMID:23830905

  7. [MicroRNAs in microglia polarization and CNS diseases: mechanism and functions].

    PubMed

    Fang, Xue; Tan, Wei-Xing; He, Cheng; Cao, Li

    2015-02-25

    Microglia are resident macrophages of central nervous system (CNS), and thus act as the crucial stuff of immune response and play very important roles in the progress of various CNS diseases. There are two different polarization statuses of activated microglia, M1 and M2 phenotypes. M1 polarized microglia are important for eradicating bacterial and promoting inflammation, whereas M2 cells are characterized by anti-inflammation and tissue remodeling. Recently, more and more evidence indicated that different polarized microglia showed diverse microRNA (miRNA) expression profiles. MiRNAs regulate microglia polarization, and thus affect the progress of CNS diseases. Fully exploring the polarization status of microglia during CNS diseases and the role of miRNAs in microglia polarization will be very helpful for a deep understanding of the roles of microglia in immunopathologic mechanism of different CNS diseases and offer the theoretical foundation of searching more effective therapies for these disorders. PMID:25672624

  8. Prenatal stress is a vulnerability factor for altered morphology and biological activity of microglia cells.

    PubMed

    Ślusarczyk, Joanna; Trojan, Ewa; Głombik, Katarzyna; Budziszewska, Bogusława; Kubera, Marta; Lasoń, Władysław; Popiołek-Barczyk, Katarzyna; Mika, Joanna; Wędzony, Krzysztof; Basta-Kaim, Agnieszka

    2015-01-01

    Several lines of evidence suggest that the dysregulation of the immune system is an important factor in the development of depression. Microglia are the resident macrophages of the central nervous system and a key player in innate immunity of the brain. We hypothesized that prenatal stress (an animal model of depression) as a priming factor could affect microglial cells and might lead to depressive-like disturbances in adult male rat offspring. We investigated the behavioral changes (sucrose preference test, Porsolt test), the expression of C1q and CD40 mRNA and the level of microglia (Iba1 positive) in 3-month-old control and prenatally stressed male offspring rats. In addition, we characterized the morphological and biochemical parameters of potentially harmful (NO, iNOS, IL-1β, IL-18, IL-6, TNF-α, CCL2, CXCL12, CCR2, CXCR4) and beneficial (insulin-like growth factor-1 (IGF-1), brain derived neurotrophic factor (BDNF)) phenotypes in cultures of microglia obtained from the cortices of 1-2 days old control and prenatally stressed pups. The adult prenatally stressed rats showed behavioral (anhedonic- and depression-like) disturbances, enhanced expression of microglial activation markers and an increased number of Iba1-immunopositive cells in the hippocampus and frontal cortex. The morphology of glia was altered in cultures from prenatally stressed rats, as demonstrated by immunofluorescence microscopy. Moreover, in these cultures, we observed enhanced expression of CD40 and MHC II and release of pro-inflammatory cytokines, including IL-1β, IL-18, TNF-α and IL-6. Prenatal stress significantly up-regulated levels of the chemokines CCL2, CXCL12 and altered expression of their receptors, CCR2 and CXCR4 while IGF-1 production was suppressed in cultures of microglia from prenatally stressed rats. Our results suggest that prenatal stress may lead to excessive microglia activation and contribute to the behavioral changes observed in depression in adulthood. PMID

  9. Rapid light-induced activation of retinal microglia in mice lacking Arrestin-1

    PubMed Central

    Levine, Emily S.; Zam, Azhar; Zhang, Pengfei; Pechko, Alina; Wang, Xinlei; FitzGerald, Paul; Pugh, Edward N.; Zawadzki, Robert J.; Burns, Marie E.

    2014-01-01

    Microglia dynamically prune synaptic contacts during development, and digest waste that accumulates in degeneration and aging. In many neurodegenerative diseases, microglial activation and phagocytosis gradually increase over months or years, with poorly defined initial triggering events. Here, we describe rapid retinal microglial activation in response to physiological light levels in a mouse model of photoreceptor degeneration that arises from defective rhodopsin deactivation and prolonged signaling. Activation, migration and proliferation of microglia proceeded along a well-defined time course apparent within 12 hours of light onset. Retinal imaging in vivo with optical coherence tomography (OCT) revealed dramatic increases in light-scattering from photoreceptors prior to the outer nuclear layer thinning classically used as a measure of retinal neurodegeneration. This model is valuable for mechanistic studies of microglial activation in a well-defined and optically accessible neural circuit, and for the development of novel methods for detecting early signs of pending neurodegeneration in vivo. PMID:25091460

  10. Forsythiaside A Exhibits Anti-inflammatory Effects in LPS-Stimulated BV2 Microglia Cells Through Activation of Nrf2/HO-1 Signaling Pathway.

    PubMed

    Wang, Yue; Zhao, Hongfei; Lin, Chuangxin; Ren, Jie; Zhang, Shizhong

    2016-04-01

    Inflammation and oxidative stress have been reported to play critical roles in the pathogenesis of neurodegenerative disease. Forsythiaside A, a phenylethanoside product isolated from air-dried fruits of Forsythia suspensa, has been reported to have anti-inflammatory and antioxidant effects. In this study, the anti-inflammatory effects of forsythiaside A on LPS-stimulated BV2 microglia cells and primary microglia cells were investigated. The production of inflammatory mediators TNF-α, IL-1β, NO and PGE2 were detected in this study. NF-κB, nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) expression were detected by western blot analysis. Our results showed that forsythiaside A significantly inhibited LPS-induced inflammatory mediators TNF-α, IL-1β, NO and PGE2 production. LPS-induced NF-κB activation was suppressed by forsythiaside A. Furthermore, forsythiaside A was found to up-regulate the expression of Nrf2 and HO-1. In conclusion, this study demonstrates that forsythiaside A inhibits LPS-induced inflammatory responses in BV2 microglia cells and primary microglia cells through inhibition of NF-κB activation and activation of Nrf2/HO-1 signaling pathway. PMID:26498935

  11. Inhibitory activity of plant stilbenoids against nitric oxide production by lipopolysaccharide-activated microglia.

    PubMed

    Nassra, Merian; Krisa, Stéphanie; Papastamoulis, Yorgos; Kapche, Gilbert Deccaux; Bisson, Jonathan; André, Caroline; Konsman, Jan-Pieter; Schmitter, Jean-Marie; Mérillon, Jean-Michel; Waffo-Téguo, Pierre

    2013-07-01

    Microglia-driven inflammatory processes are thought to play an important role in ageing and several neurological disorders. Since consumption of a diet rich in polyphenols has been associated with anti-inflammatory and neuroprotective effects, we studied the effects of twenty-five stilbenoids isolated from Milicia excelsa, Morus alba, Gnetum africanum, and Vitis vinifera. These compounds were tested at 5 and 10 µM on BV-2 microglial cells stimulated with bacterial lipopolysaccharide. Ten stilbenoids reduced lipopolysaccharide-induced nitric oxide production at 5 and/or 10 µM. Two tetramers, E-vitisin A and E-vitisin B, were the most effective molecules. Moreover, they attenuated the expression of the inducible NO synthase protein and gene. PMID:23807809

  12. Astragaloside IV inhibits microglia activation via glucocorticoid receptor mediated signaling pathway

    PubMed Central

    Liu, Hong-Shuai; Shi, Hai-Lian; Huang, Fei; Peterson, Karin E.; Wu, Hui; Lan, Yun-Yi; Zhang, Bei-Bei; He, Yi-Xin; Woods, Tyson; Du, Min; Wu, Xiao-Jun; Wang, Zheng-Tao

    2016-01-01

    Inhibition of microglia activation may provide therapeutic treatment for many neurodegenerative diseases. Astragaloside IV (ASI) with anti-inflammatory properties has been tested as a therapeutic drug in clinical trials of China. However, the mechanism of ASI inhibiting neuroinflammation is unknown. In this study, we showed that ASI inhibited microglia activation both in vivo and in vitro. It could enhance glucocorticoid receptor (GR)-luciferase activity and facilitate GR nuclear translocation in microglial cells. Molecular docking and TR-FRET GR competitive binding experiments demonstrated that ASI could bind to GR in spite of relative low affinity. Meanwhile, ASI modulated GR-mediated signaling pathway, including dephosphorylation of PI3K, Akt, I κB and NF κB, therefore, decreased downstream production of proinflammatory mediators. Suppression of microglial BV-2 activation by ASI was abrogated by GR inhibitor, RU486 or GR siRNA. Similarly, RU486 counteracted the alleviative effect of ASI on microgliosis and neuronal injury in vivo. Our findings demonstrated that ASI inhibited microglia activation at least partially by activating the glucocorticoid pathway, suggesting its possible therapeutic potential for neuroinflammation in neurological diseases. PMID:26750705

  13. TDP-43 activates microglia through NF-κB and NLRP3 inflammasome.

    PubMed

    Zhao, Weihua; Beers, David R; Bell, Shaughn; Wang, Jinghong; Wen, Shixiang; Baloh, Robert H; Appel, Stanley H

    2015-11-01

    Transactive response DNA-binding protein-43 (TDP-43) is a multifunctional nucleic acid binding protein present in ubiquitinated inclusions in tissues of patients with amyotrophic lateral sclerosis (ALS) and fronto-temporal lobar degeneration (FTLD). The ALS-associated mutations in the glycine-rich C-terminal domain of TDP-43 established a causal link between TDP-43 and disease, and conferred both loss- and gain-of-function properties in neurons. Since it has not been established whether these intra-neuronal changes are sufficient to cause ALS or whether non-cell autonomous neuronal-glial signaling could be involved, we investigated the extracellular effects of TDP-43 proteins on microglial activation and motoneuron toxicity. Wild-type, truncated 25kD C-terminal fragments, or mutant forms of TDP-43 all activated microglia and upregulated NOX2, TNF-α, and IL-1β, with WT forms being significantly less effective in activating microglia. This response to TDP-43 was mediated by its interaction with the microglial surface CD14 receptor and subsequent stimulation of the NF-κB and AP-1 pathways, as well as the intracellular inflammasome. At the cell surface, CD14 blocking antibodies suppressed microglial NF-κB activation and proinflammatory cytokine production mediated by TDP-43. Intracellularly, the NLRP3 inflammasome was induced and functional caspase-1 was produced augmenting the release of mature IL-1β. Further, TDP-43-mediated activation of microglia caused a proinflammatory cascade that was toxic to motoneurons. In the absence of microglia, TDP-43 was not toxic to motoneurons. The ability of TDP-43 to promote CD14-mediated activation of microglial NF-κB and AP-1 pathways, as well as the NLRP3 inflammasome, suggests the involvement of a non-cell autonomous proinflammatory signaling that enhances motoneuron injury, and may offer novel therapeutic targets in ALS. PMID:26222336

  14. Aryl hydrocarbon receptor mediates both proinflammatory and anti-inflammatory effects in lipopolysaccharide-activated microglia.

    PubMed

    Lee, Yi-Hsuan; Lin, Chun-Hua; Hsu, Pei-Chien; Sun, Yu-Yo; Huang, Yu-Jie; Zhuo, Jiun-Horng; Wang, Chen-Yu; Gan, Yu-Ling; Hung, Chia-Chi; Kuan, Chia-Yi; Shie, Feng-Shiun

    2015-07-01

    The aryl hydrocarbon receptor (AhR) regulates peripheral immunity; but its role in microglia-mediated neuroinflammation in the brain remains unknown. Here, we demonstrate that AhR mediates both anti-inflammatory and proinflammatory effects in lipopolysaccharide (LPS)-activated microglia. Activation of AhR by its ligands, formylindolo[3,2-b]carbazole (FICZ) or 3-methylcholanthrene (3MC), attenuated LPS-induced microglial immune responses. AhR also showed proinflammatory effects, as evidenced by the findings that genetic silence of AhR ameliorated the LPS-induced microglial immune responses and LPS-activated microglia-mediated neurotoxicity. Similarly, LPS-induced expressions of tumor necrosis factor α (TNFα) and inducible nitric oxide synthase (iNOS) were reduced in the cerebral cortex of AhR-deficient mice. Intriguingly, LPS upregulated and activated AhR in the absence of AhR ligands via the MEK1/2 signaling pathway, which effects were associated with a transient inhibition of cytochrome P450 1A1 (CYP1A1). Although AhR ligands synergistically enhance LPS-induced AhR activation, leading to suppression of LPS-induced microglial immune responses, they cannot do so on their own in microglia. Chromatin immunoprecipitation results further revealed that LPS-FICZ co-treatment, but not LPS alone, not only resulted in co-recruitment of both AhR and NFκB onto the κB site of TNFα gene promoter but also reduced LPS-induced AhR binding to the DRE site of iNOS gene promoter. Together, we provide evidence showing that microglial AhR, which can be activated by LPS, exerts bi-directional effects on the regulation of LPS-induced neuroinflammation, depending on the availability of external AhR ligands. These findings confer further insights into the potential link between environmental factors and the inflammatory brain disorders. PMID:25690886

  15. Prenatal immune activation causes hippocampal synaptic deficits in the absence of overt microglia anomalies.

    PubMed

    Giovanoli, Sandra; Weber-Stadlbauer, Ulrike; Schedlowski, Manfred; Meyer, Urs; Engler, Harald

    2016-07-01

    Prenatal exposure to infectious or inflammatory insults can increase the risk of developing neuropsychiatric disorder in later life, including schizophrenia, bipolar disorder, and autism. These brain disorders are also characterized by pre- and postsynaptic deficits. Using a well-established mouse model of maternal exposure to the viral mimetic polyriboinosinic-polyribocytidilic acid [poly(I:C)], we examined whether prenatal immune activation might cause synaptic deficits in the hippocampal formation of pubescent and adult offspring. Based on the widely appreciated role of microglia in synaptic pruning, we further explored possible associations between synaptic deficits and microglia anomalies in offspring of poly(I:C)-exposed and control mothers. We found that prenatal immune activation induced an adult onset of presynaptic hippocampal deficits (as evaluated by synaptophysin and bassoon density). The early-life insult further caused postsynaptic hippocampal deficits in pubescence (as evaluated by PSD95 and SynGAP density), some of which persisted into adulthood. In contrast, prenatal immune activation did not change microglia (or astrocyte) density, nor did it alter their activation phenotypes. The prenatal manipulation did also not cause signs of persistent systemic inflammation. Despite the absence of overt glial anomalies or systemic inflammation, adult offspring exposed to prenatal immune activation displayed increased hippocampal IL-1β levels. Taken together, our findings demonstrate that age-dependent synaptic deficits and abnormal pro-inflammatory cytokine expression can occur during postnatal brain maturation in the absence of microglial anomalies or systemic inflammation. PMID:26408796

  16. Rapid inflammasome activation in microglia contributes to brain disease in HIV/AIDS

    PubMed Central

    2014-01-01

    Background Human immunodeficiency virus type 1(HIV-1) infects and activates innate immune cells in the brain resulting in inflammation and neuronal death with accompanying neurological deficits. Induction of inflammasomes causes cleavage and release of IL-1β and IL-18, representing pathogenic processes that underlie inflammatory diseases although their contribution HIV-associated brain disease is unknown. Results Investigation of inflammasome-associated genes revealed that IL-1β, IL-18 and caspase-1 were induced in brains of HIV-infected persons and detected in brain microglial cells. HIV-1 infection induced pro-IL-1β in human microglia at 4 hr post-infection with peak IL-1β release at 24 hr, which was accompanied by intracellular ASC translocation and caspase-1 activation. HIV-dependent release of IL-1β from a human macrophage cell line, THP-1, was inhibited by NLRP3 deficiency and high extracellular [K+]. Exposure of microglia to HIV-1 gp120 caused IL-1β production and similarly, HIV-1 envelope pseudotyped viral particles induced IL-1β release, unlike VSV-G pseudotyped particles. Infection of cultured feline macrophages by the related lentivirus, feline immunodeficiency virus (FIV), also resulted in the prompt induction of IL-1β. In vivo FIV infection activated multiple inflammasome-associated genes in microglia, which was accompanied by neuronal loss in cerebral cortex and neurological deficits. Multivariate analyses of data from FIV-infected and uninfected animals disclosed that IL-1β, NLRP3 and caspase-1 expression in cerebral cortex represented key molecular determinants of neurological deficits. Conclusions NLRP3 inflammasome activation was an early and integral aspect of lentivirus infection of microglia, which was associated with lentivirus-induced brain disease. Inflammasome activation in the brain might represent a potential target for therapeutic interventions in HIV/AIDS. PMID:24886384

  17. Minocycline and Risperidone Prevent Microglia Activation and Rescue Behavioral Deficits Induced by Neonatal Intrahippocampal Injection of Lipopolysaccharide in Rats

    PubMed Central

    Ding, Yu-qiang; Liu, Yong; Zhang, Xianghui; Wu, Renrong; Guo, Xiaofeng; Zhao, Jingping

    2014-01-01

    Background Various signs of activation of microglia have been reported in schizophrenia, and it is hypothesized that microglia activation is closely associated with the neuropathology of schizophrenia. Methods Neonatal intrahippocampal injection of lipopolysaccharide (LPS), an activator of microglia, was performed in rats at postnatal day 7 (P7), and they were separately given saline, risperidone (0.5 mg/kg), minocycline (40 mg/kg) or a combination of both of them at P42 for consecutive 14 days. Behavioral changes (locomotion activity, social interaction, novel object recognition and prepulse inhibition) were examined and the number of microglia was assessed by using immunohistochemistry in adulthood. Results The adult rats in LPS-injected group showed obvious behavioral alteration (e. g. deficits in social interaction, novel object recognition and prepulse inhibition) and a dramatic increase of number of activated microglial cells in the hippocampus and other brain regions such as cerebral cortex and thalamus compared to those in saline-injected group. Interestingly, application of either minocycline, risperidone or both of them significantly rescued behavioral deficits and attenuated microglia activation. Conclusion Our results suggest that inhibition of microglia activation may be one of mechanisms underlying the antipsychotic effect of minocycline and risperidone. PMID:24705495

  18. Microglia activation is associated with IFN-α induced depressive-like behavior.

    PubMed

    Wachholz, Simone; Eßlinger, Manuela; Plümper, Jennifer; Manitz, Marie-Pierre; Juckel, Georg; Friebe, Astrid

    2016-07-01

    Inflammatory immune activation has been frequently associated with the development of major depression. This association was confirmed in patients receiving long-term treatment with pro-inflammatory interferon-α (IFN-α). Microglia, the resident immune cells in the brain, might serve as an important interface in this immune system-to-brain communication. The aim of the present study was to investigate the role of microglia in an IFN-α mouse model of immune-mediated depression. Male BALB/c mice were treated with daily injections of IFN-α for two weeks. Depressive-like behavior was analyzed in the forced swim and tail suspension test. Activation of microglia was measured by flow cytometry. Pro-inflammatory M1 type (MHC-II, CD40, CD54, CD80, CD86, CCR7), anti-inflammatory M2 type (CD206, CD200R), and maturation markers (CD11c, CCR7) were tested, as well as the chemokine receptor CCR2. IFN-α led to a significant increase in depressive-like behavior and expression of the pro-inflammatory surface markers MHC-II, CD86, and CD54, indicating M1 polarization. Because IFN-α-treated mice showed great individual variance in the behavioral response to IFN-α, they were further divided into vulnerable and non-vulnerable subgroups. Only IFN-α vulnerable mice (characterized by their development of depressive-like behavior in response to IFN-α) showed an increased expression of MHC-II and CD86, while CD54 was similarly enhanced in both subgroups. Thus, IFN-α-induced activation of microglia was specifically associated with depressive-like behavior. PMID:26408795

  19. Microglia in neuronal plasticity: Influence of stress.

    PubMed

    Delpech, Jean-Christophe; Madore, Charlotte; Nadjar, Agnes; Joffre, Corinne; Wohleb, Eric S; Layé, Sophie

    2015-09-01

    The central nervous system (CNS) has previously been regarded as an immune-privileged site with the absence of immune cell responses but this dogma was not entirely true. Microglia are the brain innate immune cells and recent findings indicate that they participate both in CNS disease and infection as well as facilitate normal CNS function. Microglia are highly plastic and play integral roles in sculpting the structure of the CNS, refining neuronal circuitry and connectivity, and contribute actively to neuronal plasticity in the healthy brain. Interestingly, psychological stress can perturb the function of microglia in association with an impaired neuronal plasticity and the development of emotional behavior alterations. As a result it seemed important to describe in this review some findings indicating that the stress-induced microglia dysfunction may underlie neuroplasticity deficits associated to many mood disorders. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'. PMID:25582288

  20. Glucosamine suppresses platelet-activating factor-induced activation of microglia through inhibition of store-operated calcium influx.

    PubMed

    Park, Jae-Hyung; Kim, Jeong-Nam; Jang, Byeong-Churl; Im, Seung-Soon; Song, Dae-Kyu; Bae, Jae-Hoon

    2016-03-01

    Microglia activation and subsequent release of inflammatory mediators are implicated in the pathophysiology of neurodegenerative diseases. Platelet-activating factor (PAF), a potent lipid mediator synthesized by microglia, is known to stimulate microglia functional responses. In this study, we determined that endogenous PAF exert autocrine effects on microglia activation, as well as the underlying mechanism involved. We also investigated the effect of D-glucosamine (GlcN) on PAF-induced cellular activation in human HMO6 microglial cells. PAF induced sustained intracellular Ca(2+) ([Ca(2+)]i) increase through store-operated Ca(2+) channels (SOC) and reactive oxygen species (ROS) generation. PAF also induced pro-inflammatory markers through NFκB/COX-2 signaling. GlcN significantly inhibited PAF-induced Ca(2+) influx and ROS generation without significant cytotoxicity. GlcN downregulated excessive expression of pro-inflammatory markers and promoted filopodia formation through NFκB/COX-2 inhibition in PAF-stimulated HMO6 cells. Taken together, these data suggest that GlcN may offer substantial therapeutic potential for treating inflammatory and neurodegenerative diseases accompanied by microglial activation. PMID:26745504

  1. Effect of rottlerin, a PKC-{delta} inhibitor, on TLR-4-dependent activation of murine microglia

    SciTech Connect

    Kim, Dong-Chan; Kim, Sun-Hee; Jeong, Min-Woo; Baek, Nam-in; Kim, Kyong-Tai . E-mail: ktk@postech.ac.kr

    2005-11-11

    In microglia, Toll-like receptors have been shown to recognize pathogen-associated molecular patterns and initiate innate immune responses upon interaction with infectious agents. The effect of rottlerin, a PKC-{delta} specific inhibitor, on TLR-4-mediated signaling was investigated in murine microglia stimulated with lipopolysaccharide and taxol. Pretreatment of microglia cells with rottlerin decreased LPS- and taxol-induced nitric oxide production in a concentration-dependent manner (IC{sub 50} = 99.1 {+-} 1.5 nM). Through MTT and FACS analysis, we found that the inhibition effect of rottlerin was not due to microglial cell death. Rottlerin pretreatment also attenuated LPS-induced phosphorylation of I{kappa}B-{alpha}, nuclear translocation of NF-{kappa}B, and expression of type II nitric oxide synthase. In addition, microglial phagocytosis in response to TLR-4 activation was diminished in which rottlerin was pretreated. Together, these data raise the possibility that certain PKC-{delta} specific inhibitors can modulate TLR-4-derived signaling and inflammatory target gene expression, and can alter susceptibility to microbial infection and chronic inflammatory diseases in central nervous system.

  2. Neurogenic Niche Microglia Undergo Positional Remodeling and Progressive Activation Contributing to Age-Associated Reductions in Neurogenesis.

    PubMed

    Solano Fonseca, Rene; Mahesula, Swetha; Apple, Deana M; Raghunathan, Rekha; Dugan, Allison; Cardona, Astrid; O'Connor, Jason; Kokovay, Erzsebet

    2016-04-01

    Neural stem cells (NSCs) exist throughout life in the ventricular-subventricular zone (V-SVZ) of the mammalian forebrain. During aging NSC function is diminished through an unclear mechanism. In this study, we establish microglia, the immune cells of the brain, as integral niche cells within the V-SVZ that undergo age-associated repositioning in the V-SVZ. Microglia become activated early before NSC deficits during aging resulting in an antineurogenic microenvironment due to increased inflammatory cytokine secretion. These age-associated changes were not observed in non-neurogenic brain regions, suggesting V-SVZ microglia are specialized. Using a sustained inflammatory model in young adult mice, we induced microglia activation and inflammation that was accompanied by reduced NSC proliferation in the V-SVZ. Furthermore, in vitro studies revealed secreted factors from activated microglia reduced proliferation and neuron production compared to secreted factors from resting microglia. Our results suggest that age-associated chronic inflammation contributes to declines in NSC function within the aging neurogenic niche. PMID:26857912

  3. Reciprocal modulation of C/EBP-α and C/EBP-β by IL-13 in activated microglia prevents neuronal death.

    PubMed

    Pan, Hung Chuan; Yang, Cheng Ning; Hung, Yi Wen; Lee, Wen Jane; Tien, Hsing Ru; Shen, Chin Chang; Sheehan, Jason; Chou, Chiang Ting; Sheu, Meei Ling

    2013-11-01

    In response to aggravation by activated microglia, IL-13 can significantly enhance ER stress induction, apoptosis, and death via reciprocal signaling through CCAAT/enhancer-binding protein alpha (C/EBP-α) and C/EBP-beta (C/EBP-β). This reciprocal signaling promotes neuronal survival. Since the induction of cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor gamma/heme oxygenase 1 (PPAR-γ/HO-1) by IL-13 plays a crucial role in the promotion of and protection from activated microglia, respectively; here, we investigated the role of IL-13 in regulating C/EBPs in activated microglia and determined its correlation with neuronal function. The results revealed that IL-13 significantly enhanced C/EBP-α/COX-2 expression and PGE2 production in LPS-treated microglial cells. Paradoxically, IL-13 abolished C/EBP-β/PPAR-γ/HO-1 expression. IL-13 also enhanced ER stress-evoked calpain activation by promoting the association of C/EBP-β and PPAR-γ. SiRNA-C/EBP-α effectively reversed the combined LPS-activated caspase-12 activation and IL-13-induced apoptosis. In contrast, siRNA-C/EBP-β partially increased microglial cell apoptosis. By NeuN immunochemistry and CD11b staining, there was improvement in the loss of CA3 neuronal cells after intrahippocampal injection of IL-13. This suggests that IL-13-enhanced PLA2 activity regulates COX-2/PGE2 expression through C/EBP-α activation. In parallel, ER stress-related calpain downregulates the PPAR-γ/HO-1 pathway via C/EBP-β and leads to aggravated death of activated microglia via IL-13, thereby preventing cerebral inflammation and neuronal injury. PMID:23881867

  4. ELECTROSTATIC CHARGE ON NANO-PARTICLES ACTIVATES CNS MACROPHAGES (MICROGLIA).

    EPA Science Inventory

    Nanometer size particles carry free radical activity on their surface and can produce oxidative stress (OS)-mediated damage upon impact to target cells. The initiating event of phage cell activation (i.e., the oxidative burst) is unknown, although many proximal events have been i...

  5. Neurotransmitter signaling in the pathophysiology of microglia

    PubMed Central

    Domercq, María; Vázquez-Villoldo, Nuria; Matute, Carlos

    2013-01-01

    Microglial cells are the resident immune cells of the central nervous system. In the resting state, microglia are highly dynamic and control the environment by rapidly extending and retracting motile processes. Microglia are closely associated with astrocytes and neurons, particularly at the synapses, and more recent data indicate that neurotransmission plays a role in regulating the morphology and function of surveying/resting microglia, as they are endowed with receptors for most known neurotransmitters. In particular, microglia express receptors for ATP and glutamate, which regulate microglial motility. After local damage, the release of ATP induces microgliosis and activated microglial cells migrate to the site of injury, proliferate, and phagocytose cells, and cellular compartments. However, excessive activation of microglia could contribute to the progression of chronic neurodegenerative diseases, though the underlying mechanisms are still unclear. Microglia have the capacity to release a large number of substances that can be detrimental to the surrounding neurons, including glutamate, ATP, and reactive oxygen species. However, how altered neurotransmission following acute insults or chronic neurodegenerative conditions modulates microglial functions is still poorly understood. This review summarizes the relevant data regarding the role of neurotransmitter receptors in microglial physiology and pathology. PMID:23626522

  6. Protective action of erythropoietin on neuronal damage induced by activated microglia.

    PubMed

    Wenker, Shirley D; Chamorro, María E; Vittori, Daniela C; Nesse, Alcira B

    2013-04-01

    Inflammation is a physiological defense response, but may also represent a potential pathological process in neurological diseases. In this regard, microglia have a crucial role in either progression or amelioration of degenerative neuronal damage. Because of the role of hypoxia in pro-inflammatory mechanisms in the nervous system, and the potential anti-inflammatory protective effect of erythropoietin (Epo), we focused our investigation on the role of this factor on activation of microglia and neuroprotection. Activation of microglial cells (EOC-2) was achieved by chemical hypoxia induced by cobalt chloride (CoCl2 ) and characterized by increased levels of nitrite, tumor necrosis factor-α and reactive oxygen species production, as well as up-regulation of inducible nitric oxide synthase expression. Under these conditions, cell proliferation data and proliferating cell nuclear antigen (PCNA) staining demonstrated a mitogenic effect of chemical hypoxia. Even though pre-treatment with Epo did not prevent nitrite production, inducible nitric oxide synthase protein expression or tumor necrosis factor-α secretion, it prevented the oxidative stress induced by CoCl2 as well as cell proliferation. Neuronal cells (SH-SY5Y) cultured in the presence of conditioned medium from activated EOC-2 cells or macrophages (RAW 264.7) developed significant apoptosis, an effect that was abolished by Epo via Epo/Epo receptor activation. The results show that even though Epo did not exert a direct anti-inflammatory effect on microglia activation, it did increase the resistance of neurons to subsequent damage from pro-inflammatory agents. In addition to its anti-apoptotic ability, the Epo antioxidant effect may have an indirect influence on neuronal survival by modulation of the pro-inflammatory environment. PMID:23384249

  7. Selective up-regulation of GLT-1 in cultured astrocytes exposed to soluble mediators released by activated microglia.

    PubMed

    Tilleux, Sébastien; Goursaud, Stéphanie; Hermans, Emmanuel

    2009-01-01

    Impaired glial glutamate uptake is commonly involved in neuronal damages observed in acute and chronic nervous disorders. As nervous insults are frequently associated with local inflammation involving microglia, this study aims at exploring the link between activated microglia and altered glutamate uptake in astrocytes. The regulation of the expression and activity of type 1 glutamate transporter (GLT-1) was examined after exposing cultures of rat astrocytes to conditioned medium from lipopolysaccharide-activated microglia cultures. Significant increases in GLT-1 mRNA expression and dihydrokainate sensitive uptake of aspartate were observed after 72h of treatment. These effects were reproduced by direct exposure of the astrocyte cultures to tumor necrosis factor alpha, a major cytokine released by activated microglia. The regulation of GLT-1 activity in response to inflammatory stimuli was also evidenced in cells exposed to dibutyryl cAMP, recognised as a model of reactive astrocytes in which the expression of this glutamate transporter is constitutively enhanced. Taken together, these results suggest that the GLT-1-dependent control of glutamate neurotransmission by either naive or chemically activated astrocytes is influenced by microglia-mediated inflammation. PMID:19428805

  8. Microglia development follows a stepwise program to regulate brain homeostasis.

    PubMed

    Matcovitch-Natan, Orit; Winter, Deborah R; Giladi, Amir; Vargas Aguilar, Stephanie; Spinrad, Amit; Sarrazin, Sandrine; Ben-Yehuda, Hila; David, Eyal; Zelada González, Fabiola; Perrin, Pierre; Keren-Shaul, Hadas; Gury, Meital; Lara-Astaiso, David; Thaiss, Christoph A; Cohen, Merav; Bahar Halpern, Keren; Baruch, Kuti; Deczkowska, Aleksandra; Lorenzo-Vivas, Erika; Itzkovitz, Shalev; Elinav, Eran; Sieweke, Michael H; Schwartz, Michal; Amit, Ido

    2016-08-19

    Microglia, the resident myeloid cells of the central nervous system, play important roles in life-long brain maintenance and in pathology. Despite their importance, their regulatory dynamics during brain development have not been fully elucidated. Using genome-wide chromatin and expression profiling coupled with single-cell transcriptomic analysis throughout development, we found that microglia undergo three temporal stages of development in synchrony with the brain--early, pre-, and adult microglia--which are under distinct regulatory circuits. Knockout of the gene encoding the adult microglia transcription factor MAFB and environmental perturbations, such as those affecting the microbiome or prenatal immune activation, led to disruption of developmental genes and immune response pathways. Together, our work identifies a stepwise microglia developmental program integrating immune response pathways that may be associated with several neurodevelopmental disorders. PMID:27338705

  9. Persistent activation of microglia and NADPH drive hippocampal dysfunction in experimental multiple sclerosis

    PubMed Central

    Di Filippo, Massimiliano; de Iure, Antonio; Giampà, Carmela; Chiasserini, Davide; Tozzi, Alessandro; Orvietani, Pier Luigi; Ghiglieri, Veronica; Tantucci, Michela; Durante, Valentina; Quiroga-Varela, Ana; Mancini, Andrea; Costa, Cinzia; Sarchielli, Paola; Fusco, Francesca Romana; Calabresi, Paolo

    2016-01-01

    Cognitive impairment is common in multiple sclerosis (MS). Unfortunately, the synaptic and molecular mechanisms underlying MS-associated cognitive dysfunction are largely unknown. We explored the presence and the underlying mechanism of cognitive and synaptic hippocampal dysfunction during the remission phase of experimental MS. Experiments were performed in a chronic-relapsing experimental autoimmune encephalomyelitis (EAE) model of MS, after the resolution of motor deficits. Immunohistochemistry and patch-clamp recordings were performed in the CA1 hippocampal area. The hole-board was utilized as cognitive/behavioural test. In the remission phase of experimental MS, hippocampal microglial cells showed signs of activation, CA1 hippocampal synapses presented an impaired long-term potentiation (LTP) and an alteration of spatial tests became evident. The activation of hippocampal microglia mediated synaptic and cognitive/behavioural alterations during EAE. Specifically, LTP blockade was found to be caused by the reactive oxygen species (ROS)-producing enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. We suggest that in the remission phase of experimental MS microglia remains activated, causing synaptic dysfunctions mediated by NADPH oxidase. Inhibition of microglial activation and NADPH oxidase may represent a promising strategy to prevent neuroplasticity impairment associated with active neuro-inflammation, with the aim to improve cognition and counteract MS disease progression. PMID:26887636

  10. In vivo imaging of activated microglia in a mouse model of focal cerebral ischemia by two-photon microscopy.

    PubMed

    Bok, Seoyeon; Wang, Taejun; Lee, Chan-Ju; Jeon, Seong-Uk; Kim, Young-Eun; Kim, Jeongwoo; Hong, Beom-Ju; Yoon, Calvin Jinse; Kim, Sungjee; Lee, Seung-Hoon; Kim, Hak Jae; Kim, Il Han; Kim, Ki Hean; Ahn, G-One

    2015-09-01

    Microglia are brain resident macrophages rapidly responding to various stimuli to exert appropriate inflammatory responses. Although they have recently been exploited as an attractive candidate for imaging neuroinflammation, it is still difficult to visualize them at the cellular and molecular levels. Here we imaged activated microglia by establishing intracranial window chamber (ICW) in a mouse model of focal cerebral ischemia by using two-photon microscopy (TPM), in vivo. Intravenous injection of fluorescent antibodies allowed us to detect significantly elevated levels of Iba-1 and CD68 positive activated microglia in the ipsilateral compared to the contralateral side of the infarct. We further observed that indomethacin, a non-steroidal anti-inflammatory drug significantly attenuated CD68-positive microglial activation in ICW, which was further confirmed by qRT-PCR biochemical analyses. In conclusion, we believe that in vivo TPM imaging of ICW would be a useful tool to screen for therapeutic interventions lowering microglial activation hence neuroinflammation. PMID:26417502

  11. In vivo imaging of activated microglia in a mouse model of focal cerebral ischemia by two-photon microscopy

    PubMed Central

    Bok, Seoyeon; Wang, Taejun; Lee, Chan-Ju; Jeon, Seong-Uk; Kim, Young-Eun; Kim, Jeongwoo; Hong, Beom-Ju; Yoon, Calvin Jinse; Kim, Sungjee; Lee, Seung-Hoon; Kim, Hak Jae; Kim, Il Han; Kim, Ki Hean; Ahn, G-One

    2015-01-01

    Microglia are brain resident macrophages rapidly responding to various stimuli to exert appropriate inflammatory responses. Although they have recently been exploited as an attractive candidate for imaging neuroinflammation, it is still difficult to visualize them at the cellular and molecular levels. Here we imaged activated microglia by establishing intracranial window chamber (ICW) in a mouse model of focal cerebral ischemia by using two-photon microscopy (TPM), in vivo. Intravenous injection of fluorescent antibodies allowed us to detect significantly elevated levels of Iba-1 and CD68 positive activated microglia in the ipsilateral compared to the contralateral side of the infarct. We further observed that indomethacin, a non-steroidal anti-inflammatory drug significantly attenuated CD68-positive microglial activation in ICW, which was further confirmed by qRT-PCR biochemical analyses. In conclusion, we believe that in vivo TPM imaging of ICW would be a useful tool to screen for therapeutic interventions lowering microglial activation hence neuroinflammation. PMID:26417502

  12. Blocking mPTP on Neural Stem Cells and Activating the Nicotinic Acetylcholine Receptor α7 Subunit on Microglia Attenuate Aβ-Induced Neurotoxicity on Neural Stem Cells.

    PubMed

    Chen, Qingzhuang; Wang, Kewan; Jiang, Deqi; Wang, Yan; Xiao, Xiaodan; Zhu, Ning; Li, Mingxing; Jia, Siyuan; Wang, Yong

    2016-06-01

    β-Amyloid (Aβ) can stimulate microglia to release a variety of proinflammatory cytokines and induce neurotoxicity. Nicotine has been reported to inhibit TNF-α, IL-1, and ROS production in microglia. Mitochondrial permeability transition pore (mPTP) plays an important role in neurotoxicity as well. Here, we investigated whether activating the microglial α7-nAChR has a neuroprotective role on neural stem cells (NSCs) and the function of mPTP in NSCs in this process. The expression of α7-nAChR in rat NSCs was detected by immunocytochemistry and RT-PCR. The viability of microglia and NSCs was examined by MTT assay. The mitochondrial membrane potential (ΔΨm) and morphological characteristics of NSCs was measured by JC-1 staining and transmission electron microscopy respectively. The distribution of cytochrome c in the subcellular regions of NSCs was visualized by confocal laser scanning microscopy, and the expression levels of cyclophilin D and cleaved caspase-3 were assayed by western blot. The apoptotic rate of NSCs was measured by flow cytometry. The expression of α7-nAChR was detected in microglial cells, but no expression was found in NSCs. The viability of rat microglial cells and NSCs was not affected by reagents or coculture itself. Aβ1-42-mediated microglial activation impaired the morphology and the ΔΨm of mitochondria of NSCs as well as increased cell apoptosis. However, the damage was attenuated when the α7-nAChRs on microglial cells were activated or the mPTPs on NSCs were blocked. Blockade of mPTPs on NSCs and activation of α7-nAChRs on microglia exhibit neuroprotective roles in Aβ-induced neurotoxicity of NSCs. PMID:26875732

  13. Fumarates modulate microglia activation through a novel HCAR2 signaling pathway and rescue synaptic dysregulation in inflamed CNS.

    PubMed

    Parodi, Benedetta; Rossi, Silvia; Morando, Sara; Cordano, Christian; Bragoni, Alberto; Motta, Caterina; Usai, Cesare; Wipke, Brian T; Scannevin, Robert H; Mancardi, Giovanni L; Centonze, Diego; Kerlero de Rosbo, Nicole; Uccelli, Antonio

    2015-08-01

    Dimethyl fumarate (DMF), recently approved as an oral immunomodulatory treatment for relapsing-remitting multiple sclerosis (MS), metabolizes to monomethyl fumarate (MMF) which crosses the blood-brain barrier and has demonstrated neuroprotective effects in experimental studies. We postulated that MMF exerts neuroprotective effects through modulation of microglia activation, a critical component of the neuroinflammatory cascade that occurs in neurodegenerative diseases such as MS. To ascertain our hypothesis and define the mechanistic pathways involved in the modulating effect of fumarates, we used real-time PCR and biochemical assays to assess changes in the molecular and functional phenotype of microglia, quantitative Western blotting to monitor activation of postulated pathway components, and ex vivo whole-cell patch clamp recording of excitatory post-synaptic currents in corticostriatal slices from mice with experimental autoimmune encephalomyelitis (EAE), a model for MS, to study synaptic transmission. We show that exposure to MMF switches the molecular and functional phenotype of activated microglia from classically activated, pro-inflammatory type to alternatively activated, neuroprotective one, through activation of the hydroxycarboxylic acid receptor 2 (HCAR2). We validate a downstream pathway mediated through the AMPK-Sirt1 axis resulting in deacetylation, and thereby inhibition, of NF-κB and, consequently, of secretion of pro-inflammatory molecules. We demonstrate through ex vivo monitoring of spontaneous glutamate-mediated excitatory post-synaptic currents of single neurons in corticostriatal slices from EAE mice that the neuroprotective effect of DMF was exerted on neurons at pre-synaptic terminals by modulating glutamate release. By exposing control slices to untreated and MMF-treated activated microglia, we confirm the modulating effect of MMF on microglia function and, thereby, its indirect neuroprotective effect at post-synaptic level. These

  14. Multimodal imaging reveals temporal and spatial microglia and matrix metalloproteinase activity after experimental stroke

    PubMed Central

    Zinnhardt, Bastian; Viel, Thomas; Wachsmuth, Lydia; Vrachimis, Alexis; Wagner, Stefan; Breyholz, Hans-Jörg; Faust, Andreas; Hermann, Sven; Kopka, Klaus; Faber, Cornelius; Dollé, Frédéric; Pappata, Sabina; Planas, Anna M; Tavitian, Bertrand; Schäfers, Michael; Sorokin, Lydia M; Kuhlmann, Michael T; Jacobs, Andreas H

    2015-01-01

    Stroke is the most common cause of death and disability from neurologic disease in humans. Activation of microglia and matrix metalloproteinases (MMPs) is involved in positively and negatively affecting stroke outcome. Novel, noninvasive, multimodal imaging methods visualizing microglial and MMP alterations were employed. The spatio-temporal dynamics of these parameters were studied in relation to blood flow changes. Micro positron emission tomography (μPET) using [18F]BR-351 showed MMP activity within the first days after transient middle cerebral artery occlusion (tMCAo), followed by increased [18F]DPA-714 uptake as a marker for microglia activation with a maximum at 14 days after tMCAo. The inflammatory response was spatially located in the infarct core and in adjacent (penumbral) tissue. For the first time, multimodal imaging based on PET, single photon emission computed tomography, and magnetic resonance imaging revealed insight into the spatio-temporal distribution of critical parameters of poststroke inflammation. This allows further evaluation of novel treatment paradigms targeting the postischemic inflammation. PMID:26126867

  15. Multimodal imaging reveals temporal and spatial microglia and matrix metalloproteinase activity after experimental stroke.

    PubMed

    Zinnhardt, Bastian; Viel, Thomas; Wachsmuth, Lydia; Vrachimis, Alexis; Wagner, Stefan; Breyholz, Hans-Jörg; Faust, Andreas; Hermann, Sven; Kopka, Klaus; Faber, Cornelius; Dollé, Frédéric; Pappata, Sabina; Planas, Anna M; Tavitian, Bertrand; Schäfers, Michael; Sorokin, Lydia M; Kuhlmann, Michael T; Jacobs, Andreas H

    2015-11-01

    Stroke is the most common cause of death and disability from neurologic disease in humans. Activation of microglia and matrix metalloproteinases (MMPs) is involved in positively and negatively affecting stroke outcome. Novel, noninvasive, multimodal imaging methods visualizing microglial and MMP alterations were employed. The spatio-temporal dynamics of these parameters were studied in relation to blood flow changes. Micro positron emission tomography (μPET) using [(18)F]BR-351 showed MMP activity within the first days after transient middle cerebral artery occlusion (tMCAo), followed by increased [(18)F]DPA-714 uptake as a marker for microglia activation with a maximum at 14 days after tMCAo. The inflammatory response was spatially located in the infarct core and in adjacent (penumbral) tissue. For the first time, multimodal imaging based on PET, single photon emission computed tomography, and magnetic resonance imaging revealed insight into the spatio-temporal distribution of critical parameters of poststroke inflammation. This allows further evaluation of novel treatment paradigms targeting the postischemic inflammation. PMID:26126867

  16. The molecular profile of microglia under the influence of glioma

    PubMed Central

    Li, Wei; Graeber, Manuel B.

    2012-01-01

    Microglia, which contribute substantially to the tumor mass of glioblastoma, have been shown to play an important role in glioma growth and invasion. While a large number of experimental studies on functional attributes of microglia in glioma provide evidence for their tumor-supporting roles, there also exist hints in support of their anti-tumor properties. Microglial activities during glioma progression seem multifaceted. They have been attributed to the receptors expressed on the microglia surface, to glioma-derived molecules that have an effect on microglia, and to the molecules released by microglia in response to their environment under glioma control, which can have autocrine effects. In this paper, the microglia and glioma literature is reviewed. We provide a synopsis of the molecular profile of microglia under the influence of glioma in order to help establish a rational basis for their potential therapeutic use. The ability of microglia precursors to cross the blood–brain barrier makes them an attractive target for the development of novel cell-based treatments of malignant glioma. PMID:22573310

  17. The molecular profile of microglia under the influence of glioma.

    PubMed

    Li, Wei; Graeber, Manuel B

    2012-08-01

    Microglia, which contribute substantially to the tumor mass of glioblastoma, have been shown to play an important role in glioma growth and invasion. While a large number of experimental studies on functional attributes of microglia in glioma provide evidence for their tumor-supporting roles, there also exist hints in support of their anti-tumor properties. Microglial activities during glioma progression seem multifaceted. They have been attributed to the receptors expressed on the microglia surface, to glioma-derived molecules that have an effect on microglia, and to the molecules released by microglia in response to their environment under glioma control, which can have autocrine effects. In this paper, the microglia and glioma literature is reviewed. We provide a synopsis of the molecular profile of microglia under the influence of glioma in order to help establish a rational basis for their potential therapeutic use. The ability of microglia precursors to cross the blood-brain barrier makes them an attractive target for the development of novel cell-based treatments of malignant glioma. PMID:22573310

  18. β-Arrestin 2-dependent activation of ERK1/2 is required for ADP-induced paxillin phosphorylation at Ser83 and microglia chemotaxis

    PubMed Central

    Lee, Sang-Hyun; Hollingsworth, Ryan; Kwon, Hyeok-Yil; Lee, Narae; Chung, Chang Y.

    2014-01-01

    Microglia play crucial roles in increased inflammation in the CNS upon brain injuries and diseases. Extracellular ADP has been reported to induce microglia chemotaxis and membrane ruffle formation through P2Y12 receptor. In this study, we examined the role of ERK1/2 activation in ADP-induced microglia chemotaxis. ADP stimulation increases the phosphorylation of ERK1/2 and paxillin phosphorylation at Tyr31 and Ser83. Inhibition of ERK1/2 significantly inhibited paxillin phosphorylation at Ser83 and the retraction of membrane ruffles, causing inefficient chemotaxis. Close examination of dynamics of focal adhesion formation with GFP-paxillin revealed that the disassembly of focal adhesions in U0126-treated cells was significantly impaired. Depletion of β-Arr2 with shRNA markedly reduced the phosphorylation of ERK1/2 and Pax/Ser83, indicating that β-Arr2 is required for ERK1/2 activation upon ADP stimulation. A large fraction of phosphorylated ERK1/2 and β-Arr2 were translocated and co-localized at focal contacts in the newly forming lamellipodia. Examination of kinetics and rate constant of paxillin formation and disassembly revealed that the phosphorylation of paxillin at Tyr31 by c-Src appears to be involved in adhesion formation upon ADP stimulation while Ser83 required for adhesion disassembly. PMID:22638989

  19. CD36 Participates in PrP106–126-Induced Activation of Microglia

    PubMed Central

    Tan, Rongrong; Shi, Fushan; Lu, Yun; Zhang, Siming; Yin, Xiaomin; Zhou, Xiangmei; Zhao, Deming

    2012-01-01

    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 (PrP106–126). We first examined the time course of CD36 mRNA expression upon exposure to PrP106–126 in BV2 microglia. We then analyzed different parameters of microglial activation in PrP106–126-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 PrP106–126. The results showed that PrP106–126 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 PrP106–126-stimulated NF-κB activation and TNF-α protein release, abrogated the PrP106–126-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 PrP106–126 –treatment, but had no effect on caspase-1 activation after treatment with a high concentration of PrP106–126. Together, these results suggest that CD36 is involved in PrP106–126-induced microglial activation and that the participation of CD36 in the interaction between PrP106–126 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

  20. Early Reduction of Microglia Activation by Irradiation in a Model of Chronic Glaucoma

    PubMed Central

    Bosco, Alejandra; Crish, Samuel D.; Steele, Michael R.; Romero, Cesar O.; Inman, Denise M.; Horner, Philip J.; Calkins, David J.; Vetter, Monica L.

    2012-01-01

    Glaucoma is a neurodegenerative disease that results in the progressive decline and ultimate death of retinal ganglion cells (RGCs). While multiple risk factors are associated with glaucoma, the mechanisms leading to onset and progression of the disease remain unknown. Molecular analysis in various glaucoma models has revealed involvement of non-neuronal cell populations, including astrocytes, Mueller glia and microglia, at early stages of glaucoma. High-dose irradiation was reported to have a significant long-term protective effect in the DBA/2J (D2) mouse model of glaucoma, although the cellular and molecular basis for this effect remains unclear. In particular, the acute effects of irradiation on specific cell populations, including non-neuronal cells, in the D2 retina and nerve have not been assessed. Here we report that irradiation induces transient reduction in proliferating microglia within the optic nerve head and glial lamina within the first week post-irradiation. This was accompanied by reduced microglial activation, with no effect on astrocyte gliosis in those regions. At later stages we confirm that early high-dose irradiation of the mouse head results in improvement of axonal structural integrity and anterograde transport function, without reduction of intraocular pressure. Thus reduced microglial activation induced by irradiation at early stages is associated with reduced optic nerve and retinal neurodegeneration in the D2 mouse model of glaucoma. PMID:22952717

  1. What is microglia neurotoxicity (Not)?

    PubMed

    Biber, Knut; Owens, Trevor; Boddeke, Erik

    2014-06-01

    Microglia most likely appeared early in evolution as they are not only present in vertebrates, but are also found in nervous systems of various nonvertebrate organisms. Mammalian microglia are derived from a specific embryonic, self-renewable myeloid cell population that is throughout lifetime not replaced by peripheral myeloid cells. These phylogenic and ontogenic features suggest that microglia serve vital functions. Yet, microglia often are described as neurotoxic cells, that actively kill (healthy) neurons. Since it is from an evolutionary point of view difficult to understand why an important 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 are normally important protective elements in the brain. This might change in chronic disease or the aged brain, where; however, it remains to be established whether microglia simply lose their protective capacities or whether microglia become truly neurotoxic cells. PMID:24590682

  2. PACAP27 prevents Parkinson-like neuronal loss and motor deficits but not microglia activation induced by prostaglandin J2.

    PubMed

    Shivers, Kai-Yvonne; Nikolopoulou, Anastasia; Machlovi, Saima Ishaq; Vallabhajosula, Shankar; Figueiredo-Pereira, Maria E

    2014-09-01

    Neuroinflammation is a major risk factor in Parkinson's disease (PD). Alternative approaches are needed to treat inflammation, as anti-inflammatory drugs such as NSAIDs that inhibit cyclooxygenase-2 (COX-2) can produce devastating side effects, including heart attack and stroke. New therapeutic strategies that target factors downstream of COX-2, such as prostaglandin J2 (PGJ2), hold tremendous promise because they will not alter the homeostatic balance offered by COX-2 derived prostanoids. In the current studies, we report that repeated microinfusion of PGJ2 into the substantia nigra of non-transgenic mice, induces three stages of pathology that mimic the slow-onset cellular and behavioral pathology of PD: mild (one injection) when only motor deficits are detectable, intermediate (two injections) when neuronal and motor deficits as well as microglia activation are detectable, and severe (four injections) when dopaminergic neuronal loss is massive accompanied by microglia activation and motor deficits. Microglia activation was evaluated in vivo by positron emission tomography (PET) with [(11)C](R)PK11195 to provide a regional estimation of brain inflammation. PACAP27 reduced dopaminergic neuronal loss and motor deficits induced by PGJ2, without preventing microglia activation. The latter could be problematic in that persistent microglia activation can exert long-term deleterious effects on neurons and behavior. In conclusion, this PGJ2-induced mouse model that mimics in part chronic inflammation, exhibits slow-onset PD-like pathology and is optimal for testing diagnostic tools such as PET, as well as therapies designed to target the integrated signaling across neurons and microglia, to fully benefit patients with PD. PMID:24970746

  3. TLR4-activated microglia require IFN-γ to induce severe neuronal dysfunction and death in situ.

    PubMed

    Papageorgiou, Ismini E; Lewen, Andrea; Galow, Lukas V; Cesetti, Tiziana; Scheffel, Jörg; Regen, Tommy; Hanisch, Uwe-Karsten; Kann, Oliver

    2016-01-01

    Microglia (tissue-resident macrophages) represent the main cell type of the innate immune system in the CNS; however, the mechanisms that control the activation of microglia are widely unknown. We systematically explored microglial activation and functional microglia-neuron interactions in organotypic hippocampal slice cultures, i.e., postnatal cortical tissue that lacks adaptive immunity. We applied electrophysiological recordings of local field potential and extracellular K(+) concentration, immunohistochemistry, design-based stereology, morphometry, Sholl analysis, and biochemical analyses. We show that chronic activation with either bacterial lipopolysaccharide through Toll-like receptor 4 (TLR4) or leukocyte cytokine IFN-γ induces reactive phenotypes in microglia associated with morphological changes, population expansion, CD11b and CD68 up-regulation, and proinflammatory cytokine (IL-1β, TNF-α, IL-6) and nitric oxide (NO) release. Notably, these reactive phenotypes only moderately alter intrinsic neuronal excitability and gamma oscillations (30-100 Hz), which emerge from precise synaptic communication of glutamatergic pyramidal cells and fast-spiking, parvalbumin-positive GABAergic interneurons, in local hippocampal networks. Short-term synaptic plasticity and extracellular potassium homeostasis during neural excitation, also reflecting astrocyte function, are unaffected. In contrast, the coactivation of TLR4 and IFN-γ receptors results in neuronal dysfunction and death, caused mainly by enhanced microglial inducible nitric oxide synthase (iNOS) expression and NO release, because iNOS inhibition is neuroprotective. Thus, activation of TLR4 in microglia in situ requires concomitant IFN-γ receptor signaling from peripheral immune cells, such as T helper type 1 and natural killer cells, to unleash neurotoxicity and inflammation-induced neurodegeneration. Our findings provide crucial mechanistic insight into the complex process of microglia activation, with

  4. PACAP27 prevents Parkinson-like neuronal loss and motor deficits but not microglia activation induced by prostaglandin J2

    PubMed Central

    Shivers, Kai-Yvonne; Nikolopoulou, Anastasia; Machlovi, Saima Ishaq; Vallabhajosula, Shankar; Figueiredo-Pereira, Maria E.

    2014-01-01

    Neuroinflammation is a major risk factor in Parkinson disease (PD). Alternative approaches are needed to treat inflammation, as anti-inflammatory drugs such as NSAIDs that inhibit cyclooxygenase-2 (COX-2) can produce devastating side effects, including heart attack and stroke. New therapeutic strategies that target factors downstream of COX-2, such as prostaglandin J2 (PGJ2), hold tremendous promise because they will not alter the homeostatic balance offered by COX-2 derived prostanoids. In the current studies, we report that repeated microinfusion of PGJ2 into the substantia nigra of non-transgenic mice, induces three stages of pathology that mimic the slow-onset cellular and behavioral pathology of PD: mild (one injection) when only motor deficits are detectable, intermediate (two injections) when neuronal and motor deficits as well as microglia activation are detectable, and severe (four injections) when dopaminergic neuronal loss is massive accompanied by microglia activation and motor deficits. Microglia activation was evaluated in vivo by positron emission tomography (PET) with [11C](R)PK11195 to provide a regional estimation of brain inflammation. PACAP27 reduced dopaminergic neuronal loss and motor deficits induced by PGJ2, without preventing microglia activation. The latter could be problematic in that persistent microglia activation can exert long-term deleterious effects on neurons and behavior. In conclusion, this PGJ2-induced mouse model that mimics in part chronic inflammation, exhibits slow-onset PD-like pathology and is optimal for testing diagnostic tools such as PET, as well as therapies designed to target the integrated signaling across neurons and microglia, to fully benefit patients with PD. PMID:24970746

  5. S100B/RAGE-dependent activation of microglia via NF-kappaB and AP-1 Co-regulation of COX-2 expression by S100B, IL-1beta and TNF-alpha.

    PubMed

    Bianchi, Roberta; Giambanco, Ileana; Donato, Rosario

    2010-04-01

    Extracellular S100B is known to affect astrocytic, neuronal and microglial activities, with different effects depending on its concentration. Whereas at relatively low concentrations S100B exerts trophic effects on neurons and astrocytes, at relatively high concentrations the protein causes neuronal apoptosis and activates astrocytes and microglia, thus potentially representing an endogenous factor implicated in neuroinflammation. We have reported that RAGE ligation by S100B in BV-2 microglia results in the upregulation of expression of the pro-inflammatory cyclo-oxygenase 2 (COX-2) via parallel Ras-Cdc42-Rac1-dependent activation of c-Jun NH(2) terminal protein kinase (JNK) and Ras-Rac1-dependent stimulation of NF-kappaB transcriptional activity. We show here that: (1) S100B also stimulates AP-1 transcriptional activity in microglia via RAGE-dependent activation of JNK; (2) S100B upregulates IL-1beta and TNF-alpha expression in microglia via RAGE engagement; and (3) S100B/RAGE-induced upregulation of COX-2, IL-1beta and TNF-alpha expression requires the concurrent activation of NF-kappaB and AP-1. We also show that S100B synergizes with IL-1beta and TNF-alpha to upregulate on COX-2 expression in microglia. Given the crucial roles of COX-2, IL-1beta and TNF-alpha in the inflammatory response, we propose that, by engaging RAGE, S100B might play an important role in microglia activation in the course of brain damage. PMID:18599158

  6. Increase in Blood Brain Barrier Permeability, Oxidative Stress, and Activated Microglia in a Rat Model of Blast Induced Traumatic Brain Injury

    PubMed Central

    Readnower, Ryan D.; Chavko, Mikulas; Adeeb, Saleena; Conroy, Michael D.; Pauly, James R.; McCarron, Richard M.; Sullivan, Patrick G.

    2010-01-01

    Traumatic brain injury (TBI) as a consequence of exposure to blast is increasingly prevalent in military populations, with the underlying pathophysiological mechanisms mostly unknown. In the present study, we utilized an air-driven shock tube to investigate the effects of blast exposure (120 kPa) on rat brains. Immediately following exposure to blast neurological function was reduced. BBB permeability was measured using IgG antibody and evaluating its immunoreactivity in the brain. At 3 and 24 h post-exposure there was a transient significant increase in IgG staining in the cortex. At 3 days post-exposure IgG immunoreactivity returned to control levels. Quantitative immunostaining was employed to determine the temporal course of brain oxidative stress following exposure to blast. Levels of 4-hydroxynonenal (4HNE) and 3-nitrotyrosine (3NT) were significantly increased at 3 h post-exposure and returned to control levels at 24 h post-exposure. The response of microglia to blast exposure was determined by autoradiographic localization of 3H-PK11195 binding. At 5 days post-exposure increased binding was observed in the contralateral and ipsilateral dentate gyrus. These regions also displayed increased binding at 10 days post-exposure; in addition to these regions there was increased binding in the contralateral ventral hippocampus and substantia nigra at this time point. Using antibodies against CD11b/c, microglia morphology characteristic of activated microglia was observed in the hippocampus and substantia nigra of animals exposed to blast. These results indicate that BBB breakdown, oxidative stress, and microglia activation likely play a role in the neuropathology associated with TBI as a result of blast exposure. PMID:20882564

  7. The Toll-like receptor 4-activated neuroprotective microglia subpopulation survives via granulocyte macrophage colony-stimulating factor and JAK2/STAT5 signaling.

    PubMed

    Kamigaki, Mayumi; Hide, Izumi; Yanase, Yuhki; Shiraki, Hiroko; Harada, Kana; Tanaka, Yoshiki; Seki, Takahiro; Shirafuji, Toshihiko; Tanaka, Shigeru; Hide, Michihiro; Sakai, Norio

    2016-02-01

    Toll-like receptor (TLR) 4 mediates inflammation and is also known to trigger apoptosis in microglia. Our time-lapse observations showed that lipopolysaccharide (LPS) stimulation induced rapid death in primary cultures of rat microglia, while a portion of the microglia escaped from death and survived for much longer than 2 days, in which time, all of the control cells had died. However, it remains unclear how the LPS-stimulated microglia subpopulation could continue to survive in the absence of any supplied growth factors. In the present study, to clarify the mechanism underlying the LPS-stimulated survival, we investigated whether microglia could produce their own survival factors in response to LPS, focusing on macrophage colony-stimulating factor (M-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-34, which are mainly supplied by astrocytes or neurons. The LPS-stimulated microglia drastically induced the expression of the GM-CSF mRNA and protein, while M-CSF and IL-34 levels were unchanged. The surviving microglia also significantly upregulated the expression of GM-CSF receptor (GM-CSFR) mRNA without affecting M-CSFR. As for the GM-CSFR downstream signal, LPS resulted in the phosphorylation of STAT5 and its translocation to the nucleus in the surviving microglia. Moreover, a specific JAK2 inhibitor, NVP-BSK805, suppressed STAT5 phosphorylation and microglia survival in response to LPS, indicating a critical role of the JAK2/STAT5 pathway in this survival mechanism. Together, these results suggest that a subpopulation of TLR4-activated microglia may survive by producing GM-CSF and up-regulating GM-CSFR. This autocrine GM-CSF pathway may activate the JAK2/STAT5 signaling pathway, which controls the transcription of survival-related genes. Finally, these surviving microglia may have neuroprotective functions because the neurons remained viable in co-cultures with these microglia. PMID:26802935

  8. The Role of Microglia in Diabetic Retinopathy

    PubMed Central

    Grigsby, Jeffery G.; Cardona, Sandra M.; Pouw, Cindy E.; Muniz, Alberto; Mendiola, Andrew S.; Tsin, Andrew T. C.; Allen, Donald M.; Cardona, Astrid E.

    2014-01-01

    There is growing evidence that chronic inflammation plays a role in both the development and progression of diabetic retinopathy. There is also evidence that molecules produced as a result of hyperglycemia can activate microglia. However the exact contribution of microglia, the resident immune cells of the central nervous system, to retinal tissue damage during diabetes remains unclear. Current data suggest that dysregulated microglial responses are linked to their deleterious effects in several neurological diseases associated with chronic inflammation. As inflammatory cytokines and hyperglycemia disseminate through the diabetic retina, microglia can change to an activated state, increase in number, translocate through the retina, and themselves become the producers of inflammatory and apoptotic molecules or alternatively exert anti-inflammatory effects. In addition, microglial genetic variations may account for some of the individual differences commonly seen in patient's susceptibility to diabetic retinopathy. PMID:25258680

  9. CX3CR1 deficiency suppresses activation and neurotoxicity of microglia/macrophage in experimental ischemic stroke

    PubMed Central

    2014-01-01

    Background Chemokine (C-X3-C motif) ligand 1 (CX3CL1)/ CX3C chemokine receptor 1 (CX3CR1) signaling is important in modulating the communication between neurons and resident microglia/migrated macrophages in the central nervous system (CNS). Although CX3CR1 deficiency is associated with an improved outcome following ischemic brain injury, the mechanism of this observation is largely unknown. The aim of this study was to investigate how CX3CR1 deficiency influences microglia/macrophage functions in the context of its protection following brain ischemia. Methods Wild-type (WT) and CX3CR1-deficient (CX3CR1-/-) mice were subjected to transient middle cerebral artery occlusion (MCAO) and reperfusion. The ischemic brain damage was monitored by rodent high-field magnetic resonance imaging. Neurological deficit was assessed daily. Neuronal apoptotic death and reactive oxygen species (ROS) production were analyzed by immunostaining and live imaging. Activation/inflammatory response of microglia/macrophage were assessed using immunohistochemistry, flow cytometry, 5-bromo-2-deoxyuridine labeling, cytokine ELISA, and real-time PCR. Results CX3CR1-/- mice displayed significantly smaller infarcts and less severe neurological deficits compared to WT controls, following MCAO. In addition, CX3CR1-/- MCAO mice displayed fewer apoptotic neurons and reduced ROS levels. Impaired CX3CR1 signaling abrogated the recruitment of monocyte-derived macrophages from the periphery, suppressed the proliferation of CNS microglia and infiltrated macrophage, facilitated the alternative activation (M2 state) of microglia/macrophages, and attenuated their ability to synthesize and release inflammatory cytokines. Conclusion Our results suggest that inhibition of CX3CR1 signaling could function as a therapeutic modality in ischemic brain injury, by reducing recruitment of peripheral macrophages and expansion/activation of CNS microglia and macrophages, resulting in protection of neurological function

  10. TRAM1 Promotes Microglia M1 Polarization.

    PubMed

    Wang, Hanxiang; Liu, Chun; Han, Ming; Cheng, Chun; Zhang, Dongmei

    2016-02-01

    Microglia, the major immune cells of the central nervous system (CNS), can be driven to adopt M1 and M2 phenotypes. Recently, the distinct functions of M1 and M2 microglia have been intensively studied. M1-activation microglia are pro-inflammatory and may contribute to the development of several CSN disorders, while M2-activation microglia are anti-inflammatory and may promote tissue reconstruction. TRAM1 is a protein involved in translocation of nascent polypeptides and functions as a sorting adaptor of TLR4. Here, we found that TRAM1 plays an important role in microglia M1 polarization. Our results showed that the expression of TRAM1 is highly induced in LPS/interferon (IFN)-γ-stimulated BV2 cells and primary microglia cells. Flag-TRAM1 transfection, but not Flag-GFP used as a control, significantly enhanced M1 polarization by strongly increasing expression of M1 makers, such as IL-6, IL-1β, iNOS, and so on. Silence of TRAM1 effectively inhibited LPS/IFN-γ-induced expression of M1-related genes in BV2 cells. In addition, TRAM1 was found to cooperate with TLR4 to induce an M1 genetic program in Flag-TRAM1-transfected and LPS/IFN-γ-induced BV2 cells. TRAM1 is essential for LPS/IFN-γ induced expressions of adapter molecule (IRAK1, phosphorylation of TBK1, and IRF3) of TLR4. TRAM1 is also essential for phosphorylation of IκB and P65 and for P65-NF-kB translocation to nucleus. Overall, our findings showed that TRAM1 could promote microglia M1 polarization. PMID:26563450

  11. Active Gaming: The Future of Play?

    ERIC Educational Resources Information Center

    Witherspoon, Lisa; Manning, John P.

    2012-01-01

    The authors examine technology-driven games--especially active gaming--as an evolving form of children's play. They offer an overview of play and its developmental benefits, describe the literature on the emergence of technology-driven play, and reflect on the diminishment of physical play in contemporary culture. They suggest that active gaming,…

  12. Anti-Inflammatory Effects of α-Galactosylceramide Analogs in Activated Microglia: Involvement of the p38 MAPK Signaling Pathway

    PubMed Central

    Chung, Young Sun; Park, Seung Bum; Kim, Hee-Sun

    2014-01-01

    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. PMID:24523867

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

    PubMed

    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. PMID:26214311

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

    PubMed

    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. PMID:25782915

  15. CHF5074 (CSP-1103) induces microglia alternative activation in plaque-free Tg2576 mice and primary glial cultures exposed to beta-amyloid.

    PubMed

    Porrini, V; Lanzillotta, A; Branca, C; Benarese, M; Parrella, E; Lorenzini, L; Calzà, L; Flaibani, R; Spano, P F; Imbimbo, B P; Pizzi, M

    2015-08-27

    Activation of microglia associated with neuroinflammation and loss of phagocytic activity is considered to play a prominent role in the pathogenesis of Alzheimer's disease (AD). CHF5074 (CSP-1103) has been shown to improve cognition and reduce brain inflammation in patients with mild cognitive impairment (MCI). CHF5074 was also found to reverse impairments in recognition memory and improve hippocampal long-term potentiation when administered to plaque-free Tg2576 mice (5-month-old) for 4 weeks. Though, no investigation has focused on the consequence of CHF5074 treatment on microglia polarization yet. In this study we evaluated the effect of CHF5074 administration (375 ppm in the diet) to 5-month-old Tg2576 mice on the expression of pro-inflammatory (M1) genes, Interleukin 1 beta (IL-1β), Tumor Necrosis Factor alpha (TNFα) and inducible Nitric Oxide Synthase (iNOS), and anti-inflammatory/phagocytic (M2) markers Mannose Receptor type C 1 (MRC1/CD206), Triggering Receptor Expressed on Myeloid cells 2 (TREM2) and Chitinase 3-like 3 (Ym1). No changes of pro-inflammatory gene transcription but a reduced expression of MRC1/CD206, TREM2 and Ym1 were detected in the hippocampus of young Tg2576 mice receiving normal diet, when compared to wild-type littermates. CHF5074 did not affect the pro-inflammatory transcription but significantly increased the expression of MRC1/CD206 and Ym1. CHF5074 effects appeared to be hippocampus-specific, as the M2 transcripts were only slightly modified in the cerebral cortex. In primary cultures of mouse astrocyte-microglia, CHF5074 totally suppressed the expression of TNF-α, IL-1β and iNOS induced by 10 μM β-amyloid1-42 (Aβ42). Moreover, CHF5074 significantly increased the expression of anti-inflammatory/phagocytic markers MRC1/CD206 and TREM2, reduced by the Aβ42 application alone. The effect of CHF5074 was not reproduced by ibuprofen (3 μM or 500 μM) or R-flurbiprofen (3 μM or 100 μM), as both compounds limited the pro

  16. The Biphasic Role of Microglia in Alzheimer's Disease

    PubMed Central

    Mizuno, Tetsuya

    2012-01-01

    Neuroinflammation is involved in the pathogenesis of Alzheimer's disease (AD). Microglia, macrophage-like resident immune cells in the brain, play critical roles in the inflammatory aspects of AD. Microglia may be activated by oligomeric and fibrillar species of amyloid β (Aβ) that are constituents of senile plaques and by molecules derived from degenerated neurons, such as purines and chemokines, which enhance their migration and phagocytosis. The main neurotoxic molecules produced by activated microglia may be reactive oxygen species, glutamate, and inflammatory cytokines such as tumor-necrosis-factor-α and interleukin- (IL-) 1β These molecules differentially induce neurotoxicity. Aβ itself directly damages neurons. In terms of neuroprotective properties, microglia treated with fractalkine or IL-34 attenuate Aβ neurotoxicity by Aβ clearance and the production of antioxidants. Therefore, regulation of the microglial role in neuroprotection may be a useful therapeutic strategy for AD. PMID:22655214

  17. Pedunculopontine cell loss and protein aggregation direct microglia activation in parkinsonian rats.

    PubMed

    Elson, Joanna L; Yates, Abi; Pienaar, Ilse S

    2016-05-01

    We previously reported a loss of cholinergic neurons within the pedunculopontine tegmental nucleus (PPTg) in rats that had been intra-nigrally lesioned with the proteasomal inhibitor lactacystin, with levels of neuronal loss corresponding to that seen in the post-mortem pedunculopontine nucleus (PPN) of advanced Parkinson's disease (PD) patients. Here we reveal lower expression values of the acetylcholine synthesising enzyme, choline acetyltransferase, within the remaining PPTg cholinergic neurons of lesioned rats compared to sham controls. We further characterise this animal model entailing dopaminergic- and non-dopaminergic neurodegeneration by reporting on stereological counts of non-cholinergic neurons, to determine whether the toxin is neuro-type specific. Cell counts between lesioned and sham-lesioned rats were analysed in terms of the topological distribution pattern across the rostro-caudal extent of the PPTg. The study also reports somatic hypotrophy in the remaining non-cholinergic neurons, particularly on the side closest to the nigral lesion. The cytotoxicity affecting the PPTg in this rat model of PD involves overexpression and accumulation of alpha-synuclein (αSYN), affecting cholinergic and non-cholinergic neurons as well as microglia on the lesioned hemispheric side. We ascertained that microglia within the PPTg become fully activated due to the extensive neuronal damage and neuronal death resulting from a lactacystin nigral lesion, displaying a distinct rostro-caudal distribution profile which correlates with PPTg neuronal loss, with the added implication that lactacystin-induced αSYN aggregation might trigger neuronophagia for promoting PPTg cell loss. The data provide critical insights into the mechanisms underlying the lactacystin rat model of PD, for studying the PPTg in health and when modelling neurodegenerative disease. PMID:25989851

  18. Microglia activation: one of the checkpoints in the CNS inflammation caused by Angiostrongylus cantonensis infection in rodent model.

    PubMed

    Wei, Jie; Wu, Feng; He, Ai; Zeng, Xin; Ouyang, Li-si; Liu, Ming-she; Zheng, Huan-qin; Lei, Wan-long; Wu, Zhong-dao; Lv, Zhi-yue

    2015-09-01

    Angiostrongylus cantonensis (A. cantonensis) is a rodent nematode. Adult worms of A. cantonensis live in the pulmonary arteries of rats; humans are non-permissive hosts like the mice. The larva cannot develop into an adult worm and only causes serious eosinophilic meningitis or meningo-encephalitis if humans or mice eat food containing larva of A. cantonensis in the third stage. The differing consequences largely depend on differing immune responses of hosts to parasite during A. cantonensis invasion and development. To further understand the reasons why mice and rats attain different outcomes in A. cantonensis infection, we used the HE staining to observe the pathological changes of infected mice and rats. In addition, we measured mRNA levels of some cytokines (IL-5, IL-6, IL-13, Eotaxin, IL-4, IL-10, TGF-β, IFN-γ, IL-17A, TNF-α, IL-1β, and iNOS) in brain tissues of mice and rats by real-time PCR. The result showed that brain inflammation in mice was more serious than in rats. Meanwhile, mRNA expression levels of IL-6, IL-1β, TNF-α, and iNOS increased after mice were infected. In contrast, mRNA levels of these cytokines in rats brain tissues decreased at post- infection 21 days. These cytokines mostly were secreted by activated microglia in central nervous system. Microglia of mice and rats were showed by Iba-1 (microglia marker) staining. In micee brains, microglia got together and had more significant activation than in rats brains. The results demonstrate that mice and rats have different CNS inflammation after infection by A. cantonensis, and it is in line with other researchers' reported findings. In conclusion, it is suggested that microglia activation is probably to be one of the most important factors in angiostrongyliasis from our study. PMID:26002828

  19. Go with your gut: microbiota meet microglia

    PubMed Central

    Mosher, Kira Irving; Wyss-Coray, Tony

    2016-01-01

    Discovering the environmental factors that control microglia is key to understanding and managing brain health. A new study finds that microbiota in the gut are essential for regulating microglia maturation and activation. PMID:26108718

  20. PARP-1 Inhibition Attenuates Neuronal Loss, Microglia Activation and Neurological Deficits after Traumatic Brain Injury

    PubMed Central

    Loane, David J.; Zhao, Zaorui; Kabadi, Shruti V.; Hanscom, Marie; Byrnes, Kimberly R.; Faden, Alan I.

    2014-01-01

    Abstract Traumatic brain injury (TBI) causes neuronal cell death as well as microglial activation and related neurotoxicity that contribute to subsequent neurological dysfunction. Poly (ADP-ribose) polymerase (PARP-1) induces neuronal cell death through activation of caspase-independent mechanisms, including release of apoptosis inducing factor (AIF), and microglial activation. Administration of PJ34, a selective PARP-1 inhibitor, reduced cell death of primary cortical neurons exposed to N-Methyl-N'-Nitro-N-Nitrosoguanidine (MNNG), a potent inducer of AIF-dependent cell death. PJ34 also attenuated lipopolysaccharide and interferon-γ-induced activation of BV2 or primary microglia, limiting NF-κB activity and iNOS expression as well as decreasing generation of reactive oxygen species and TNFα. Systemic administration of PJ34 starting as late as 24 h after controlled cortical impact resulted in improved motor function recovery in mice with TBI. Stereological analysis demonstrated that PJ34 treatment reduced the lesion volume, attenuated neuronal cell loss in the cortex and thalamus, and reduced microglial activation in the TBI cortex. PJ34 treatment did not improve cognitive performance in a Morris water maze test or reduce neuronal cell loss in the hippocampus. Overall, our data indicate that PJ34 has a significant, albeit selective, neuroprotective effect after experimental TBI, and its therapeutic effect may be from multipotential actions on neuronal cell death and neuroinflammatory pathways. PMID:24476502

  1. Microglia contact induces synapse formation in developing somatosensory cortex.

    PubMed

    Miyamoto, Akiko; Wake, Hiroaki; Ishikawa, Ayako Wendy; Eto, Kei; Shibata, Keisuke; Murakoshi, Hideji; Koizumi, Schuichi; Moorhouse, Andrew J; Yoshimura, Yumiko; Nabekura, Junichi

    2016-01-01

    Microglia are the immune cells of the central nervous system that play important roles in brain pathologies. Microglia also help shape neuronal circuits during development, via phagocytosing weak synapses and regulating neurogenesis. Using in vivo multiphoton imaging of layer 2/3 pyramidal neurons in the developing somatosensory cortex, we demonstrate here that microglial contact with dendrites directly induces filopodia formation. This filopodia formation occurs only around postnatal day 8-10, a period of intense synaptogenesis and when microglia have an activated phenotype. Filopodia formation is preceded by contact-induced Ca(2+) transients and actin accumulation. Inhibition of microglia by genetic ablation decreases subsequent spine density, functional excitatory synapses and reduces the relative connectivity from layer 4 neurons. Our data provide the direct demonstration of microglial-induced spine formation and provide further insights into immune system regulation of neuronal circuit development, with potential implications for developmental disorders of immune and brain dysfunction. PMID:27558646

  2. Microglia contact induces synapse formation in developing somatosensory cortex

    PubMed Central

    Miyamoto, Akiko; Wake, Hiroaki; Ishikawa, Ayako Wendy; Eto, Kei; Shibata, Keisuke; Murakoshi, Hideji; Koizumi, Schuichi; Moorhouse, Andrew J.; Yoshimura, Yumiko; Nabekura, Junichi

    2016-01-01

    Microglia are the immune cells of the central nervous system that play important roles in brain pathologies. Microglia also help shape neuronal circuits during development, via phagocytosing weak synapses and regulating neurogenesis. Using in vivo multiphoton imaging of layer 2/3 pyramidal neurons in the developing somatosensory cortex, we demonstrate here that microglial contact with dendrites directly induces filopodia formation. This filopodia formation occurs only around postnatal day 8–10, a period of intense synaptogenesis and when microglia have an activated phenotype. Filopodia formation is preceded by contact-induced Ca2+ transients and actin accumulation. Inhibition of microglia by genetic ablation decreases subsequent spine density, functional excitatory synapses and reduces the relative connectivity from layer 4 neurons. Our data provide the direct demonstration of microglial-induced spine formation and provide further insights into immune system regulation of neuronal circuit development, with potential implications for developmental disorders of immune and brain dysfunction. PMID:27558646

  3. Activated microglia mediate axo-glial disruption that contributes to axonal injury in multiple sclerosis

    PubMed Central

    Garg, Anurag; Komada, Masayuki; Brophy, Peter. J.; Reynolds, Richard

    2015-01-01

    The complex symptoms of chronic multiple sclerosis (MS) are due, in part, to widespread axonal pathology affecting lesioned and non-lesioned areas of the CNS. Here we describe an association between microglial activation and axon/ oligodendrocyte pathology at nodal and paranodal domains in normal appearing white matter (NAWM) of MS and experimental allergic encephalomyelitis (EAE). The extent of paranodal axo-glial (neurofascin-155+/Caspr1+) disruption correlated with the local degree of microglial inflammation and axonal injury (expression of nonphosphorylated neurofilaments) in MS NAWM. These changes were independent of demyelinating lesions and did not correlate with the density of infiltrating lymphocytes. Similar axo-glial alterations were seen in pre-symptomatic EAE, at a time-point characterised by microglia activation prior to the infiltration of immune cells. Disruption of the axo-glial unit in adjuvant immunised animals was reversible and coincided with the resolution of microglial inflammation, whereas paranodal damage and microglial inflammation persisted in chronic EAE. We were able to preserve axo-glial integrity by administering minocycline, which inhibited microglial activation, in actively immunised animals. Therefore, permanent disruption to axo-glial domains in an environment of microglial inflammation is an early indicator of axonal injury that would affect normal nerve conduction contributing to pathology outside of the demyelinated lesion. PMID:20838243

  4. Experimental manipulations of microglia in mouse models of Alzheimer’s pathology. Activation reduces amyloid but hastens tau pathology

    PubMed Central

    Lee, Daniel C.; Rizer, Justin; Hunt, Jerry B.; Selenica, Maj-Linda B.; Gordon, Marcia N.; Morgan, Dave

    2015-01-01

    The inflammation hypothesis of Alzheimer’s pathogenesis has directed much scientific effort towards ameliorating this disease. The development of mouse models of amyloid deposition permitted direct tests of the proposal that amyloid-activated microglia could cause neurodegeneration in vivo. Many approaches to manipulating microglial activation have been applied to these mouse models, and are the subject of this review. In general, these results do not support a direct neuricidal action of microglia in mouse amyloid models under any activation state. Some of the manipulations cause both a reduction in pathology, and a reduction in microglial activation. However, at least for agents like ibuprofen, this outcome may result from a direct action on amyloid production, and a reduction in the microglial provoking amyloid deposits, rather than from reduced microglial activation leading to a decline in amyloid deposition. Instead, a surprising number of the experimental manipulations which increase microglial activation lead to enhanced clearance of the amyloid deposits. Both the literature and new data presented here suggest that either classical or alternative activation of microglia can lead to enhanced amyloid clearance. However, a limited number of studies comparing the same treatments in amyloid-depositing vs tau-depositing mice find the opposite effects. Treatments that benefit amyloid pathology accelerate tau pathology. This observation argues strongly that potential treatments be tested for impact on both amyloid and tau pathology before consideration of testing in humans. PMID:23171029

  5. Microglia in mouse retina contralateral to experimental glaucoma exhibit multiple signs of activation in all retinal layers

    PubMed Central

    2014-01-01

    Background Glaucomatous optic neuropathy, a leading cause of blindness, can progress despite control of intraocular pressure - currently the main risk factor and target for treatment. Glaucoma progression shares mechanisms with neurodegenerative disease, including microglia activation. In the present model of ocular hypertension (OHT), we have recently described morphological signs of retinal microglia activation and MHC-II upregulation in both the untreated contralateral eyes and OHT eyes. By using immunostaining, we sought to analyze and quantify additional signs of microglia activation and differences depending on the retinal layer. Methods Two groups of adult Swiss mice were used: age-matched control (naïve, n = 12), and lasered (n = 12). In the lasered animals, both OHT eyes and contralateral eyes were analyzed. Retinal whole-mounts were immunostained with antibodies against Iba-1, MHC-II, CD68, CD86, and Ym1. The Iba-1+ cell number in the plexiform layers (PL) and the photoreceptor outer segment (OS), Iba-1+ arbor area in the PL, and area of the retina occupied by Iba-1+ cells in the nerve fiber layer-ganglion cell layer (NFL-GCL) were quantified. Results The main findings in contralateral eyes and OHT eyes were: i) ameboid microglia in the NFL-GCL and OS; ii) the retraction of processes in all retinal layers; iii) a higher level of branching in PL and in the OS; iv) soma displacement to the nearest cell layers in the PL and OS; v) the reorientation of processes in the OS; vi) MHC-II upregulation in all retinal layers; vii) increased CD68 immunostaining; and viii) CD86 immunolabeling in ameboid cells. In comparison with the control group, a significant increase in the microglial number in the PL, OS, and in the area occupied by Iba-1+ cells in the NFL-GCL, and significant reduction of the arbor area in the PL. In addition, rounded Iba-1+ CD86+ cells in the NFL-GCL, OS and Ym1+ cells, and rod-like microglia in the NFL-GCL were restricted to OHT eyes

  6. Inhibition of phagocytosis and lysosomal acidification suppresses neurotoxic prion peptide-induced NALP3 inflammasome activation in BV2 microglia.

    PubMed

    Shi, Fushan; Yang, Yang; Kouadir, Mohammed; Fu, Yongyao; Yang, Lifeng; Zhou, Xiangmei; Yin, Xiaomin; Zhao, Deming

    2013-07-15

    Prion diseases are neurodegenerative disorders characterized by the accumulation of misfolded prion protein. In a previous study, we showed that neurotoxic prion peptide (PrP106-126) induced NALP3 inflammasome activation in mouse primary and immortalized microglia. In the present work, we examined the relevance of phagocytosis and lysosomal acidification to the activation of the NALP3 inflammasome in PrP106-126-stimulated microglia. Our results showed that the inhibition of phagocytosis or lysosomal acidification significantly reduced IL-1β and IL-18 production, downregulated NALP3 and ASC expression, and decreased the expression of proinflammatory factors. We concluded that phagocytosis and lysosomal acidification are necessary for PrP106-126-induced NALP3 activation in BV2 cells. PMID:23680490

  7. Amelioration of LPS-Induced Inflammation Response in Microglia by AMPK Activation

    PubMed Central

    Chen, Chin-Chen; Lin, Jiun-Tsai; Cheng, Yi-Fang; Kuo, Cheng-Yi; Huang, Chun-Fang; Kao, Shao-Hsuan; Liang, Yao-Jen; Cheng, Ching-Yi; Chen, Han-Min

    2014-01-01

    Adenosine 5′-monophosphate-activated protein kinase (AMPK) is a key regulator of cellular energy homeostasis via modulating metabolism of glucose, lipid, and protein. In addition to energy modulation, AMPK has been demonstrated to associate with several important cellular events including inflammation. The results showed that ENERGI-F704 identified from bamboo shoot extract was nontoxic in concentrations up to 80 μM and dose-dependently induced phosphorylation of AMPK (Thr-172) in microglia BV2 cells. Our findings also showed that the treatment of BV2 with ENERGI-F704 ameliorated the LPS-induced elevation of IL-6 and TNF-α production. In addition, ENERGI-F704 reduced increased production of nitric oxide (NO) and prostaglandin E2 (PGE2) via downregulating the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2), respectively. Moreover, ENERGI-F704 decreased activated nuclear translocation and protein level of NF-κB. Inhibition of AMPK with compound C restored decreased NF-κB translocation by ENERGI-F704. In conclusion, ENERGI-F704 exerts inhibitory activity on LPS-induced inflammation through manipulating AMPK signaling and exhibits a potential therapeutic agent for neuroinflammatory disease. PMID:25025067

  8. CCR2 overexpression promotes the efficient recruitment of retinal microglia in vitro

    PubMed Central

    Jiang, Xiao-shuang; Liu, Tian-jin; Zhang, Meng; Ren, Hui; Jiang, Rui; Huang, Xin; Xu, Ge-zhi

    2012-01-01

    Purpose Retinal microglia can be activated and recruited by chemokines and play a protective role in early retinal degeneration. CC-chemokine ligand 2 (CCL2) and its receptor, CC-chemokine receptor 2 (CCR2), have been implicated as key mediators for the trafficking and accumulation of microglial cells in lesioned tissue. The current study investigates whether the overexpression of CCR2 allows microglia to migrate toward CCL2 more efficiently. Methods Primary microglial cells were transduced with lentivirus carrying green fluorescent protein (GFP)-tagged CCR2 (CCR2-GFP). Overexpression of CCR2 was assessed by western blot analysis and fluorescence-assisted cell sorting. The chemotaxis of primary microglia transduced with lentivirus carrying CCR2-GFP was compared to either those transduced with GFP alone or those not transduced, using a chemotaxis chamber assay. Results Primary microglia showed a high transduction rate following lentivirus application and maintained normal microglial morphology and a significant overexpression of CCR2 protein. We found that CCL2-mediated chemotaxis is concentration and time dependent in microglia. The chemotactic response of microglia cells overexpressing CCR2-GFP was significantly increased compared to that of nontransduced and GFP-expressing microglia. Conclusions These findings suggest that microglia can be efficiently transduced with CCR2-GFP lentiviral vectors and that the overexpression of CCR2 in retinal microglia promotes their chemotaxis in response to chemokines, suggesting that these cells may be promising targets for cell-based therapeutic manipulation in retinal disease. PMID:23288990

  9. The Ca2+ release-activated Ca2+ current (I(CRAC)) mediates store-operated Ca2+ entry in rat microglia.

    PubMed

    Ohana, Lily; Newell, Evan W; Stanley, Elise F; Schlichter, Lyanne C

    2009-01-01

    Ca2+ signaling plays a central role in microglial activation, and several studies have demonstrated a store-operated Ca2+ entry (SOCE) pathway to supply this ion. Due to the rapid pace of discovery of novel Ca2+ permeable channels, and limited electrophysiological analyses of Ca2+ currents in microglia, characterization of the SOCE channels remains incomplete. At present, the prime candidates are 'transient receptor potential' (TRP) channels and the recently cloned Orai1, which produces a Ca2+-release-activated Ca2+ (CRAC) current. We used cultured rat microglia and real-time RT-PCR to compare expression levels of Orai1, Orai2, Orai3, TRPM2, TRPM7, TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6 and TRPC7 channel genes. Next, we used Fura-2 imaging to identify a store-operated Ca2+ entry pathway that was reduced by depolarization and blocked by Gd3+, SKF-96365, diethylstilbestrol (DES), and a high concentration of 2-aminoethoxydiphenyl borate (50 microM 2-APB). The Fura-2 signal was increased by hyperpolarization, and by a low concentration of 2-APB (5 microM), and exhibited Ca(2+)-dependent potentiation. These properties are entirely consistent with Orai1/CRAC, rather than any known TRP channel and this conclusion was supported by patch-clamp electrophysiological analysis. We identified a store-operated Ca2+ current with the same properties, including high selectivity for Ca2+ over monovalent cations, pronounced inward rectification and a very positive reversal potential, Ca(2+)-dependent current potentiation, and block by SKF-96365, DES and 50 microM 2-APB. Determining the contribution of Orai1/CRAC in different cell types is crucial to future mechanistic and therapeutic studies; this comprehensive multi-strategy analysis demonstrates that Orai1/CRAC channels are responsible for SOCE in primary microglia. PMID:19411837

  10. Nanostructured TiO2 surfaces promote polarized activation of microglia, but not astrocytes, toward a proinflammatory profile

    NASA Astrophysics Data System (ADS)

    de Astis, Silvia; Corradini, Irene; Morini, Raffaella; Rodighiero, Simona; Tomasoni, Romana; Lenardi, Cristina; Verderio, Claudia; Milani, Paolo; Matteoli, Michela

    2013-10-01

    Activation of glial cells, including astrocytes and microglia, has been implicated in the inflammatory responses underlying brain injury and neurodegenerative diseases including Alzheimer's and Parkinson's diseases. The classic activation state (M1) is characterized by high capacity to present antigens, high production of nitric oxide (NO) and reactive oxygen species (ROS) and proinflammatory cytokines. Classically activated cells act as potent effectors that drive the inflammatory response and may mediate detrimental effects on neural cells. The second phenotype (M2) is an alternative, apparently beneficial, activation state, more related to a fine tuning of inflammation, scavenging of debris, promotion of angiogenesis, tissue remodeling and repair. Specific environmental chemical signals are able to induce these different polarization states. We provide here evidence that nanostructured substrates are able, exclusively in virtue of their physical properties, to push microglia toward the proinflammatory activation phenotype, with an efficacy which reflects the graded nanoscale rugosity. The acquisition of a proinflammatory phenotype appears specific for microglia and not astrocytes, indicating that these two cell types, although sharing common innate immune responses, respond differently to external physical stimuli.

  11. Blockade of gap junction hemichannel protects secondary spinal cord injury from activated microglia-mediated glutamate exitoneurotoxicity.

    PubMed

    Umebayashi, Daisuke; Natsume, Atsushi; Takeuchi, Hideyuki; Hara, Masahito; Nishimura, Yusuke; Fukuyama, Ryuichi; Sumiyoshi, Naoyuki; Wakabayashi, Toshihiko

    2014-12-15

    We previously demonstrated that activated microglia release excessive glutamate through gap junction hemichannels and identified a novel gap junction hemichannel blocker, INI-0602, that was proven to penetrate the blood-brain barrier and be an effective treatment in mouse models of amyotrophic lateral sclerosis and Alzheimer disease. Spinal cord injury causes tissue damage in two successive waves. The initial injury is mechanical and directly causes primary tissue damage, which induces subsequent ischemia, inflammation, and neurotoxic factor release resulting in the secondary tissue damage. These lead to activation of glial cells. Activated glial cells such as microglia and astrocytes are common pathological observations in the damaged lesion. Activated microglia release glutamate, the major neurotoxic factor released into the extracellular space after neural injury, which causes neuronal death at high concentration. In the present study, we demonstrate that reduction of glutamate-mediated exitotoxicity via intraperitoneal administration of INI-0602 in the microenvironment of the injured spinal cord elicited neurobehavioral recovery and extensive suppression of glial scar formation by reducing secondary tissue damage. Further, this intervention stimulated anti-inflammatory cytokines, and subsequently elevated brain-derived neurotrophic factor. Thus, preventing microglial activation by a gap junction hemichannel blocker, INI-0602, may be a promising therapeutic strategy in spinal cord injury. PMID:24588281

  12. Involvement of endoplasmic reticulum stress in the necroptosis of microglia/macrophages after spinal cord injury.

    PubMed

    Fan, H; Tang, H-B; Kang, J; Shan, L; Song, H; Zhu, K; Wang, J; Ju, G; Wang, Y-Z

    2015-12-17

    Microglia/macrophages play a crucial role in inflammation after spinal cord injury (SCI). Although extensive studies have been performed on the mechanisms of microglia/macrophage activation and recruitment, how microglia/macrophages are eliminated remains unclear. In the present study, we observed a high-level expression of mixed lineage kinase domain-like protein (MLKL), a key molecule in the execution of necroptosis, in microglia/macrophages after SCI in mice. In vivo PI-labeling and Necrostatin-1 treatment confirmed the necroptosis of microglia/macrophages. Interestingly, our electronic microscopic (EM) study revealed that MLKL localized not only at the membrane but also on the endoplasmic reticulum (ER) of necroptotic microglia/macrophages. Furthermore, receptor-interacting protein 3 (RIP3), another necrosome component, was also found on the ER of necroptotic microglia/macrophages. And Glucose-regulated protein 78 (GRP78), an ER stress sensor, was up-regulated in MLKL-positive microglia/macrophages after SCI, suggesting a possible link between necroptosis and ER stress. In vitro, oxygen-glucose deprivation (OGD) stress induced ER stress and necroptosis in microglia. Inhibiting ER stress by 4-phenylbutyrate (4-PBA) significantly blocked the OGD-induced necroptosis of microglia. In the end, our data showed that, GRP78 and phosphorylated MLKL were co-expressed by the microglia/macrophages in the injured human spinal cord. Taken together, these results suggested that microglia/macrophages undergo an ER-stress involved necroptosis after SCI, implying that ER stress and necroptosis could be manipulated for modulating inflammation post-SCI. PMID:26523978

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

    PubMed

    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. PMID:27335254

  14. Caspase-1 inhibition attenuates activation of BV2 microglia induced by LPS-treated RAW264.7 macrophages

    PubMed Central

    Pan, Yang; Shen, Bo; Gao, Qin; Zhu, Jun; Dong, Jingde; Zhang, Li; Zhang, Yingdong

    2016-01-01

    Abstract Neuroinflammation has been recognized as a factor in the pathogenesis of neurodegenerative diseases. Emerging evidence suggests that peripheral inflammation, besides neuroinflammation, functions as a modulator of disease progression and neuropathology in several neurodegenerative diseases. However, detailed correlations among peripheral inflammation, neuroinflammation and neurodegeneration remain unknown. In the present study, we prepared a peripheral inflammation model with lipopolysaccharides (LPS)-stimulated RAW264.7 macrophages to explore its activation on BV2 microglia. We found that LPS induced the production of IL-1β, IL-6 and TNF-α in the culture medium of RAW264.7 macrophages. We further showed that LPS plus ATP activated inflammasome, evidenced by the upregulation of caspase-1 and IL-1β, which was suppressed by ZYVAD, a caspase-1 inhibitor. Furthermore, the conditioned medium obtained from LPS-treated RAW264.7 macrophages activated BV2 microglia, stimulating the release of IL-1β, IL-6 and TNF-α from BV2 cells. ZYVAD pretreatment markedly suppressed BV2 microglia activation induced by RAW264.7 cells conditioned medium. Taken together, our study indicates that macrophage-mediated peripheral inflammation subsequently evokes neuroinflammation and may aggravate neural damage. Inflammasome and caspase-1 may be potential targets for modulating systemic inflammatory responses in neurodegenerative diseases.

  15. Girls' Physically Active Play and Parental Behavior.

    ERIC Educational Resources Information Center

    Tauber, Margaret A.

    Sex differences in children's physical activity levels, and associations between girls' activity level, childrearing characteristics and parent-child play behavior were investigated in a quasi-naturalistic situation. As part of a longitudinal project, 144 third grade children were videotaped in a 1-hour play session with one of their parents. A…

  16. Microglia Ontology and Signaling

    PubMed Central

    ElAli, Ayman; Rivest, Serge

    2016-01-01

    Microglia constitute the powerhouse of the innate immune system in the brain. It is now widely accepted that they are monocytic-derived cells that infiltrate the developing brain at the early embryonic stages, and acquire a resting phenotype characterized by the presence of dense branching processes, called ramifications. Microglia use these dynamic ramifications as sentinels to sense and detect any occurring alteration in brain homeostasis. Once a danger signal is detected, such as molecular factors associated to brain damage or infection, they get activated by acquiring a less ramified phenotype, and mount adequate responses that range from phagocyting cell debris to secreting inflammatory and trophic factors. Here, we review the origin of microglia and we summarize the main molecular signals involved in controlling their function under physiological conditions. In addition, their implication in the pathogenesis of multiple sclerosis and stress is discussed. PMID:27446922

  17. Microglia and astrocyte activation in the frontal cortex of rats with experimental autoimmune encephalomyelitis.

    PubMed

    Chanaday, N L; Roth, G A

    2016-02-01

    Experimental autoimmune encephalomyelitis (EAE) is a widely used animal model for the human disease multiple sclerosis (MS), a demyelinating and neurodegenerative pathology of the central nervous system. Both diseases share physiopathological and clinical characteristics, mainly associated with a neuroinflammatory process that leads to a set of motor, sensory, and cognitive symptoms. In MS, gray matter atrophy is related to the emergence of cognitive deficits and contributes to clinical progression. In particular, injury and dysfunction in certain areas of the frontal cortex (FrCx) have been related to the development of cognitive impairments with high incidence, like central fatigue and executive dysfunction. In the present work we show the presence of region-specific microglia and astrocyte activation in the FrCx, during the first hours of acute EAE onset. It is accompanied by the production of the pro-inflammatory cytokines IL-6 and TNF-α, in the absence of detectable leukocyte infiltration. These findings expand previous studies showing presynaptic neural dysfunction occurring at the FrCx and might contribute to the understanding of the mechanisms involved in the genesis and prevalence of common MS symptoms. PMID:26679600

  18. Chronic stress enhances microglia activation and exacerbates death of nigral dopaminergic neurons under conditions of inflammation

    PubMed Central

    2014-01-01

    Background Parkinson’s disease is an irreversible neurodegenerative disease linked to progressive movement disorders and is accompanied by an inflammatory reaction that is believed to contribute to its pathogenesis. Since sensitivity to inflammation is not the same in all brain structures, the aim of this work was to test whether physiological conditions as stress could enhance susceptibility to inflammation in the substantia nigra, where death of dopaminergic neurons takes place in Parkinson’s disease. Methods To achieve our aim, we induced an inflammatory process in nonstressed and stressed rats (subject to a chronic variate stress) by a single intranigral injection of lipopolysaccharide, a potent proinflammogen. The effect of this treatment was evaluated on inflammatory markers as well as on neuronal and glial populations. Results Data showed a synergistic effect between inflammation and stress, thus resulting in higher microglial activation and expression of proinflammatory markers. More important, the higher inflammatory response seen in stressed animals was associated with a higher rate of death of dopaminergic neurons in the substantia nigra, the most characteristic feature seen in Parkinson’s disease. This effect was dependent on glucocorticoids. Conclusions Our data demonstrate that stress sensitises midbrain microglia to further inflammatory stimulus. This suggests that stress may be an important risk factor in the degenerative processes and symptoms of Parkinson’s disease. PMID:24565378

  19. Impaired Spatial Learning Memory after Isoflurane Anesthesia or Appendectomy in Aged Mice is Associated with Microglia Activation

    PubMed Central

    Wang, Hui-Lin; Ma, Rui-Hua; Fang, Hao; Xue, Zhang-Gang; Liao, Qing-Wu

    2015-01-01

    Postoperative cognitive dysfunction (POCD) has been one of the most common problems in elderly patients following surgery. But the specific mechanism of POCD is still not clear. To further understand the reason of these postoperative behavioral deficits, we evaluated the spatial learning memory of both adult (3 months) and aged (18 months) male mice, 3 or 28 days after isoflurane (Iso) exposure for two hours or appendectomy (App). Hippocampal microglia activation and IL-1β, TNF-α, and IFN-γ expression were also evaluated at day 3, day 14 and day 28 after Iso exposure or appendectomy. Results showed that spatial learning memory of aged, but not adult, mice was impaired after Iso exposure or appendectomy, accompanied with more hippocampal microglia activation and IL-1β, TNF-α, and IFN-γ overexpression. These findings suggest that the cognitive deficits of elderly patients who have undergone surgeries are quite possibly caused by hippocampal microglia overactivation and the subsequent inflammation. PMID:26380557

  20. Isolation of highly enriched primary human microglia for functional studies.

    PubMed

    Rustenhoven, Justin; Park, Thomas I-H; Schweder, Patrick; Scotter, John; Correia, Jason; Smith, Amy M; Gibbons, Hannah M; Oldfield, Robyn L; Bergin, Peter S; Mee, Edward W; Faull, Richard L M; Curtis, Maurice A; Scott Graham, E; Dragunow, Mike

    2016-01-01

    Microglia, the resident macrophages of the central nervous system play vital roles in brain homeostasis through clearance of pathogenic material. Microglia are also implicated in neurological disorders through uncontrolled activation and inflammatory responses. To date, the vast majority of microglial studies have been performed using rodent models. Human microglia differ from rodent counterparts in several aspects including their response to pharmacological substances and their inflammatory secretions. Such differences highlight the need for studies on primary adult human brain microglia and methods to isolate them are therefore required. Our procedure generates microglial cultures of >95% purity from both biopsy and autopsy human brain tissue using a very simple media-based culture procedure that takes advantage of the adherent properties of these cells. Microglia obtained in this manner can be utilised for research within a week. Isolated microglia demonstrate phagocytic ability and respond to inflammatory stimuli and their purity makes them suitable for numerous other forms of in vitro studies, including secretome and transcriptome analysis. Furthermore, this protocol allows for the simultaneous isolation of neural precursor cells during the microglial isolation procedure. As human brain tissue is such a precious and valuable resource the simultaneous isolation of multiple cell types is highly beneficial. PMID:26778406

  1. Do Microglia Default on Network Maintenance in Alzheimer’s Disease?

    PubMed Central

    Southam, Katherine A.; Vincent, Adele J.; Small, David H.

    2016-01-01

    Although the cause of Alzheimer’s disease (AD) remains unknown, a number of new findings suggest that the immune system may play a critical role in the early stages of the disease. Genome-wide association studies have identified a wide array of risk-associated genes for AD, many of which are associated with abnormal functioning of immune cells. Microglia are the brain’s immune cells. They play an important role in maintaining the brain’s extracellular environment, including clearance of aggregated proteins such as amyloid-β (Aβ). Recent studies suggest that microglia play a more active role in the brain than initially considered. Specifically, microglia provide trophic support to neurons and also regulate synapses. Microglial regulation of neuronal activity may have important consequences for AD. In this article we review the function of microglia in AD and examine the possible relationship between microglial dysfunction and network abnormalities, which occur very early in disease pathogenesis. PMID:26890782

  2. Regulation of caspase-3 processing by cIAP2 controls the switch between pro-inflammatory activation and cell death in microglia

    PubMed Central

    Kavanagh, E; Rodhe, J; Burguillos, M A; Venero, J L; Joseph, B

    2014-01-01

    The activation of microglia, resident immune cells of the central nervous system, and inflammation-mediated neurotoxicity are typical features of neurodegenerative diseases, for example, Alzheimer's and Parkinson's diseases. An unexpected role of caspase-3, commonly known to have executioner role for apoptosis, was uncovered in the microglia activation process. A central question emerging from this finding is what prevents caspase-3 during the microglia activation from killing those cells? Caspase-3 activation occurs as a two-step process, where the zymogen is first cleaved by upstream caspases, such as caspase-8, to form intermediate, yet still active, p19/p12 complex; thereafter, autocatalytic processing generates the fully mature p17/p12 form of the enzyme. Here, we show that the induction of cellular inhibitor of apoptosis protein 2 (cIAP2) expression upon microglia activation prevents the conversion of caspase-3 p19 subunit to p17 subunit and is responsible for restraining caspase-3 in terms of activity and subcellular localization. We demonstrate that counteracting the repressive effect of cIAP2 on caspase-3 activation, using small interfering RNA targeting cIAP2 or a SMAC mimetic such as the BV6 compound, reduced the pro-inflammatory activation of microglia cells and promoted their death. We propose that the different caspase-3 functions in microglia, and potentially other cell types, reside in the active caspase-3 complexes formed. These results also could indicate cIAP2 as a possible therapeutic target to modulate microglia pro-inflammatory activation and associated neurotoxicity observed in neurodegenerative disorders. PMID:25501826

  3. Regulation of caspase-3 processing by cIAP2 controls the switch between pro-inflammatory activation and cell death in microglia.

    PubMed

    Kavanagh, E; Rodhe, J; Burguillos, M A; Venero, J L; Joseph, B

    2014-01-01

    The activation of microglia, resident immune cells of the central nervous system, and inflammation-mediated neurotoxicity are typical features of neurodegenerative diseases, for example, Alzheimer's and Parkinson's diseases. An unexpected role of caspase-3, commonly known to have executioner role for apoptosis, was uncovered in the microglia activation process. A central question emerging from this finding is what prevents caspase-3 during the microglia activation from killing those cells? Caspase-3 activation occurs as a two-step process, where the zymogen is first cleaved by upstream caspases, such as caspase-8, to form intermediate, yet still active, p19/p12 complex; thereafter, autocatalytic processing generates the fully mature p17/p12 form of the enzyme. Here, we show that the induction of cellular inhibitor of apoptosis protein 2 (cIAP2) expression upon microglia activation prevents the conversion of caspase-3 p19 subunit to p17 subunit and is responsible for restraining caspase-3 in terms of activity and subcellular localization. We demonstrate that counteracting the repressive effect of cIAP2 on caspase-3 activation, using small interfering RNA targeting cIAP2 or a SMAC mimetic such as the BV6 compound, reduced the pro-inflammatory activation of microglia cells and promoted their death. We propose that the different caspase-3 functions in microglia, and potentially other cell types, reside in the active caspase-3 complexes formed. These results also could indicate cIAP2 as a possible therapeutic target to modulate microglia pro-inflammatory activation and associated neurotoxicity observed in neurodegenerative disorders. PMID:25501826

  4. Bee venom phospholipase A2 ameliorates motor dysfunction and modulates microglia activation in Parkinson's disease alpha-synuclein transgenic mice.

    PubMed

    Ye, Minsook; Chung, Hwan-Suck; Lee, Chanju; Hyun Song, Joo; Shim, Insop; Kim, Youn-Sub; Bae, Hyunsu

    2016-01-01

    α-Synuclein (α-Syn) has a critical role in microglia-mediated neuroinflammation, which leads to the development of Parkinson's disease (PD). Recent studies have shown that bee venom (BV) has beneficial effects on PD symptoms in human patients or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxin-induced PD mice. This study investigated whether treatment with BV-derived phospholipase A2 (bvPLA2) would improve the motor dysfunction and pathological features of PD in human A53T α-Syn mutant transgenic (A53T Tg) mice. The motor dysfunction of A53T Tg mice was assessed using the pole test. The levels of α-Syn, microglia and the M1/M2 phenotype in the spinal cord were evaluated by immunofluorescence. bvPLA2 treatment significantly ameliorated motor dysfunction in A53T Tg mice. In addition, bvPLA2 significantly reduced the expression of α-Syn, the activation and numbers of microglia, and the ratio of M1/M2 in A53T Tg mice. These results suggest that bvPLA2 could be a promising treatment option for PD. PMID:27388550

  5. Bee venom phospholipase A2 ameliorates motor dysfunction and modulates microglia activation in Parkinson's disease alpha-synuclein transgenic mice

    PubMed Central

    Ye, Minsook; Chung, Hwan-Suck; Lee, Chanju; Hyun Song, Joo; Shim, Insop; Kim, Youn-Sub; Bae, Hyunsu

    2016-01-01

    α-Synuclein (α-Syn) has a critical role in microglia-mediated neuroinflammation, which leads to the development of Parkinson's disease (PD). Recent studies have shown that bee venom (BV) has beneficial effects on PD symptoms in human patients or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxin-induced PD mice. This study investigated whether treatment with BV-derived phospholipase A2 (bvPLA2) would improve the motor dysfunction and pathological features of PD in human A53T α-Syn mutant transgenic (A53T Tg) mice. The motor dysfunction of A53T Tg mice was assessed using the pole test. The levels of α-Syn, microglia and the M1/M2 phenotype in the spinal cord were evaluated by immunofluorescence. bvPLA2 treatment significantly ameliorated motor dysfunction in A53T Tg mice. In addition, bvPLA2 significantly reduced the expression of α-Syn, the activation and numbers of microglia, and the ratio of M1/M2 in A53T Tg mice. These results suggest that bvPLA2 could be a promising treatment option for PD. PMID:27388550

  6. IMM-H004, a novel coumarin derivative compound, attenuates the production of inflammatory mediatory mediators in lipopolysaccharide-activated BV2 microglia.

    PubMed

    Song, Xiu-Yun; Hu, Jin-Feng; Sun, Ming-Na; Li, Zhi-Peng; Zhu, Zhi-Xiang; Song, Lian-Kun; Yuan, Yu-He; Liu, Gang; Chen, Nai-Hong

    2014-07-01

    Therapeutic strategies designed to inhibit the activation of microglia may lead to significant advancement in the treatment of most neurodegenerative diseases. 7-hydroxy-5-methoxy-4-methyl-3-(4-methylpiperazin-1-yl)-coumarin (IMM-H004) is a novel compound and has been reported exerting potent neuroprotective effects which may be related to anti-inflammation. In the present study, the anti-inflammatory effects of IMM-H004 were investigated in lipopolysaccharide (LPS)-treated BV2 microglia. Our observations indicated that treatment with IMM-H004 significantly inhibited BV2 microglia activation, protected PC12 cells and primary neurons against indirect toxicity mediated by exposure to conditioned medium (CM) from LPS-treated BV2 cells. Additionally, IMM-H004 significantly suppressed the release of TNF-α, IL-1β and NO, and suppressed the expression of pro-inflammatory mediators and cytokines such as iNOS, COX-2, and IL-6 in LPS-stimulated BV2 microglia. The nuclear translocation of NF-κB and the phosphorylation level of JNK and p38 MAPK pathways were also inhibited by IMM-H004 in LPS-treated BV2 microglia. Moreover, IMM-H004 also was a strong selective OH scavenger whose effect was similar with vitamin C. Overall, our findings suggested that IMM-H004 might be a promising therapeutic agent for alleviating the progress of neurodegenerative diseases associated with microglia activation. PMID:24878446

  7. Scutellarin as a Potential Therapeutic Agent for Microglia-Mediated Neuroinflammation in Cerebral Ischemia.

    PubMed

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

    2016-09-01

    The cerebral ischemia is one of the most common diseases in the central nervous system that causes progressive disability or even death. In this connection, the inflammatory response mediated by the activated microglia is believed to play a central role in this pathogenesis. In the event of brain injury, activated microglia can clear the cellular debris and invading pathogens, release neurotrophic factors, etc., but in chronic activation microglia may cause neuronal death through the release of excessive inflammatory mediators. Therefore, suppression of microglial over-reaction and microglia-mediated neuroinflammation is deemed to be a therapeutic strategy of choice for cerebral ischemic damage. In the search for potential herbal extracts that are endowed with the property in suppressing the microglial activation and amelioration of neuroinflammation, attention has recently been drawn to scutellarin, a Chinese herbal extract. Here, we review the roles of activated microglia and the effects of scutellarin on activated microglia in pathological conditions especially in ischemic stroke. We have further extended the investigation with special reference to the effects of scutellarin on Notch signaling, one of the several signaling pathways known to be involved in microglial activation. Furthermore, in light of our recent experimental evidence that activated microglia can regulate astrogliosis, an interglial "cross-talk" that was amplified by scutellarin, it is suggested that in designing of a more effective therapeutic strategy for clinical management of cerebral ischemia both glial types should be considered collectively. PMID:27103430

  8. Role of Microglia in Neurotrauma

    PubMed Central

    Loane, David J.; Byrnes, Kimberly R.

    2010-01-01

    Microglia are the primary mediators of the central nervous system's (CNS) immune defense system and are integral to the subsequent inflammatory response. The role of microglia in the injured CNS is under scrutiny as research has begun to fully explore how post-injury inflammation contributes to secondary damage and recovery of function. Whether microglia are ‘good’ or ‘bad’ is under debate, with strong support for a dual role or differential activation of microglia. Microglia release a number of factors that modulate secondary injury and recovery after injury, including pro- and anti-inflammatory cytokines, chemokines, nitric oxide, prostaglandins, growth factors and superoxide species. Here we review experimental work on the complex and varied responses of microglia in terms of both detrimental and beneficial effects. In addition, the impact of microglial activation in two examples of CNS injury - spinal cord and traumatic brain injury - will be discussed. Microglial activation is integral to the response of CNS tissue to injury. As such, future research should now focus on clarifying the signals and mechanisms by which microglia can be guided to promote optimal functional recovery. PMID:20880501

  9. Position Statement on Active Outdoor Play

    PubMed Central

    Tremblay, Mark S.; Gray, Casey; Babcock, Shawna; Barnes, Joel; Costas Bradstreet, Christa; Carr, Dawn; Chabot, Guylaine; Choquette, Louise; Chorney, David; Collyer, Cam; Herrington, Susan; Janson, Katherine; Janssen, Ian; Larouche, Richard; Pickett, William; Power, Marlene; Sandseter, Ellen Beate Hansen; Simon, Brenda; Brussoni, Mariana

    2015-01-01

    A diverse, cross-sectorial group of partners, stakeholders and researchers, collaborated to develop an evidence-informed Position Statement on active outdoor play for children aged 3–12 years. The Position Statement was created in response to practitioner, academic, legal, insurance and public debate, dialogue and disagreement on the relative benefits and harms of active (including risky) outdoor play. The Position Statement development process was informed by two systematic reviews, a critical appraisal of the current literature and existing position statements, engagement of research experts (N = 9) and cross-sectorial individuals/organizations (N = 17), and an extensive stakeholder consultation process (N = 1908). More than 95% of the stakeholders consulted strongly agreed or somewhat agreed with the Position Statement; 14/17 participating individuals/organizations endorsed it; and over 1000 additional individuals and organizations requested their name be listed as a supporter. The final Position Statement on Active Outdoor Play states: “Access to active play in nature and outdoors—with its risks— is essential for healthy child development. We recommend increasing children’s opportunities for self-directed play outdoors in all settings—at home, at school, in child care, the community and nature.” The full Position Statement provides context for the statement, evidence supporting it, and a series of recommendations to increase active outdoor play opportunities to promote healthy child development. PMID:26062040

  10. Position Statement on Active Outdoor Play.

    PubMed

    Tremblay, Mark S; Gray, Casey; Babcock, Shawna; Barnes, Joel; Bradstreet, Christa Costas; Carr, Dawn; Chabot, Guylaine; Choquette, Louise; Chorney, David; Collyer, Cam; Herrington, Susan; Janson, Katherine; Janssen, Ian; Larouche, Richard; Pickett, William; Power, Marlene; Sandseter, Ellen Beate Hansen; Simon, Brenda; Brussoni, Mariana

    2015-06-01

    A diverse, cross-sectorial group of partners, stakeholders and researchers, collaborated to develop an evidence-informed Position Statement on active outdoor play for children aged 3-12 years. The Position Statement was created in response to practitioner, academic, legal, insurance and public debate, dialogue and disagreement on the relative benefits and harms of active (including risky) outdoor play. The Position Statement development process was informed by two systematic reviews, a critical appraisal of the current literature and existing position statements, engagement of research experts (N=9) and cross-sectorial individuals/organizations (N=17), and an extensive stakeholder consultation process (N=1908). More than 95% of the stakeholders consulted strongly agreed or somewhat agreed with the Position Statement; 14/17 participating individuals/organizations endorsed it; and over 1000 additional individuals and organizations requested their name be listed as a supporter. The final Position Statement on Active Outdoor Play states: "Access to active play in nature and outdoors--with its risks--is essential for healthy child development. We recommend increasing children's opportunities for self-directed play outdoors in all settings--at home, at school, in child care, the community and nature." The full Position Statement provides context for the statement, evidence supporting it, and a series of recommendations to increase active outdoor play opportunities to promote healthy child development. PMID:26062040

  11. Increased neuroplasticity and hippocampal microglia activation in a mice model of rapid antidepressant treatment.

    PubMed

    Muzio, Luca; Brambilla, Valentina; Calcaterra, Lorenza; D'Adamo, Patrizia; Martino, Gianvito; Benedetti, Francesco

    2016-09-15

    The search for biomarkers of antidepressant effects focused on pathways regulating synaptic plasticity, and on activated inflammatory markers. Repeated Sleep Deprivation (SD) provides a model treatment to reverse-translate antidepressant effects from in vivo clinical psychiatry to model organisms. We studied the effects of repeated SD alone (ASD) or combined with exercise on a slow spinning wheel (SSW), in 116 C57BL/6J male mice divided in three groups (ASD, SSW, untreated). Forced Swimming Test (FST) was used to detect antidepressant-like effects. Unbiased evaluation of the transcriptional responses were obtained in the hippocampus by Illumina Bead Chip Array system, then confirmed with real time PCR. Spine densities in granular neurons of the dentate gyrus (DG) were assayed by standard Golgi staining. Activation of Microglial/Macrophages cells was evaluated by immunufluorescence analysis for Iba1. Rates of cell proliferation was estimated pulsing mice with the S-phase tracer 5-Iodo-2'-deoxyuridine (IdU). All SD procedures caused a decreasing of floating time at FST, and increased expression of the immediate early gene Arc/Arg3.1. In addition, SSW also increased expression of the Microglia/Macrophages genes Iba-1 and chemokine receptors Cx3cR1 and CxcR4, of the canonical Wnt signaling gene Wnt7a, and of dendritic spines in CA4 neurons of the DG. SSW up-regulated both the number of Iba1+ cells and rates of cell proliferation in the subgranular region of the DG. The antidepressant-like effects of SD dissociated both, from hippocampal neuroplasticity in the DG (not occurring after ASD), and from microglial activation (not preventing behavioral response when occurring). The increase in dendritic spine density in the DG after SD and exercise was associated with an up-regulation of Wnt 7a, and with activation of the innate immune system of the brain. Increased Arc/Arg3.1 suggests however increased neuroplasticity, which could be common to all fast-acting antidepressants

  12. Histamine modulates microglia function

    PubMed Central

    2012-01-01

    Background Histamine is commonly acknowledged as an inflammatory mediator in peripheral tissues, leaving its role in brain immune responses scarcely studied. Therefore, our aim was to uncover the cellular and molecular mechanisms elicited by this molecule and its receptors in microglia-induced inflammation by evaluating cell migration and inflammatory mediator release. Methods Firstly, we detected the expression of all known histamine receptor subtypes (H1R, H2R, H3R and H4R), using a murine microglial cell line and primary microglia cell cultures from rat cortex, by real-time PCR analysis, immunocytochemistry and Western blotting. Then, we evaluated the role of histamine in microglial cell motility by performing scratch wound assays. Results were further confirmed using murine cortex explants. Finally, interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels were evaluated by ELISA measurements to determine the role of histamine on the release of these inflammatory mediators. Results After 12 h of treatment, 100 μM histamine and 10 μg/ml histamine-loaded poly (lactic-co-glycolic acid) microparticles significantly stimulated microglia motility via H4R activation. In addition, migration involves α5β1 integrins, and p38 and Akt signaling pathways. Migration of microglial cells was also enhanced in the presence of lipopolysaccharide (LPS, 100 ng/ml), used as a positive control. Importantly, histamine inhibited LPS-stimulated migration via H4R activation. Histamine or H4R agonist also inhibited LPS-induced IL-1β release in both N9 microglia cell line and hippocampal organotypic slice cultures. Conclusions To our knowledge, we are the first to show a dual role of histamine in the modulation of microglial inflammatory responses. Altogether, our data suggest that histamine per se triggers microglia motility, whereas histamine impedes LPS-induced microglia migration and IL-1β release. This last datum assigns a new putative anti-inflammatory role for

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

    SciTech Connect

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

    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. Acetylsalicylic acid enhances the anti-inflammatory effect of fluoxetine through inhibition of NF-κB, p38-MAPK and ERK1/2 activation in lipopolysaccharide-induced BV-2 microglia cells.

    PubMed

    Yang, J M; Rui, B B; Chen, C; Chen, H; Xu, T J; Xu, W P; Wei, W

    2014-09-01

    The latest advancements in neurobiological research provide increasing evidence that inflammatory and neurodegenerative pathways play an important role in depression. According to the cytokine hypothesis, depression could be due to the increased production of pro-inflammatory cytokines by microglia activation. Thus, using the BV-2 microglial cell line, the aim of the present study was to investigate whether fluoxetine (FLX) or acetylsalicylic acid (ASA) could inhibit this microglia activation and could achieve better results in combination. Our results showed that FLX could attenuate lipopolysaccharide (LPS)-induced production of interleukin-1β (IL-1β), the expression of the indoleamine 2,3 dioxygenase (IDO) enzyme and the depletion of 5-HT. Moreover, FLX could inhibit phosphorylation of nuclear factor-κB (NF-κB) and phosphorylation of p38 mitogen-activated protein kinase (MAPK), and the combined use with ASA could enhance these effects. Notably, the adjunctive agent ASA could also inhibit phosphorylation of extracellular-regulated kinase 1/2 (ERK1/2). Taken together, our results suggest that FLX may have some anti-inflammatory effects by modulating microglia activation and that ASA served as an effective adjunctive agent by enhancing these therapeutic effects. PMID:24952332

  15. Third Harmonic Generation microscopy as a diagnostic tool for the investigation of microglia BV-2 and breast cancer cells activation

    NASA Astrophysics Data System (ADS)

    Gavgiotaki, E.; Filippidis, G.; Psilodimitrakopoulos, S.; Markomanolaki, H.; Kalognomou, M.; Agelaki, S.; Georgoulias, V.; Athanassakis, I.

    2015-07-01

    Nonlinear optical imaging techniques have created new opportunities of research in the biomedical field. Specifically, Third Harmonic Generation (THG) seems to be a suitable noninvasive imaging tool for the delineation and quantification of biological structures at the microscopic level. The aim of this study was to extract information as to the activation state of different cell types by using the THG imaging microscopy as a diagnostic tool. BV-2 microglia cell line was used as a representative biological model enabling the study of resting and activated state of the cells linked to various pathological conditions. Third Harmonic Generation (THG) and Two Photon Excitation Fluorescence (TPEF) measurements were simultaneously collected from stained breast cancer cells, by employing a single homemade experimental apparatus and it was shown that high THG signals mostly arise from lipid bodies. Continuously, BV-2 microglia cells were examined with or without activation by lipopolysaccharide (LPS) in order to discriminate between control and activated cells based on the quantification of THG signals. Statistically quantification was accomplished in both mean area and mean intensity values of THG. The values for mean total area and mean THG intensity values have been increased in activated versus the non-activated cells. Similar studies of quantification are underway in breast cancer cells for the exact discrimination on different cell lines. Furthermore, laser polarization dependence of SHG and THG signal in unstained biological samples is investigated.

  16. Microglia Control Neuronal Network Excitability via BDNF Signalling

    PubMed Central

    2013-01-01

    Microglia-neuron interactions play a crucial role in several neurological disorders characterized by altered neural network excitability, such as epilepsy and neuropathic pain. While a series of potential messengers have been postulated as substrates of the communication between microglia and neurons, including cytokines, purines, prostaglandins, and nitric oxide, the specific links between messengers, microglia, neuronal networks, and diseases have remained elusive. Brain-derived neurotrophic factor (BDNF) released by microglia emerges as an exception in this riddle. Here, we review the current knowledge on the role played by microglial BDNF in controlling neuronal excitability by causing disinhibition. The efforts made by different laboratories during the last decade have collectively provided a robust mechanistic paradigm which elucidates the mechanisms involved in the synthesis and release of BDNF from microglia, the downstream TrkB-mediated signals in neurons, and the biophysical mechanism by which disinhibition occurs, via the downregulation of the K+-Cl− cotransporter KCC2, dysrupting Cl−homeostasis, and hence the strength of GABAA- and glycine receptor-mediated inhibition. The resulting altered network activity appears to explain several features of the associated pathologies. Targeting the molecular players involved in this canonical signaling pathway may lead to novel therapeutic approach for ameliorating a wide array of neural dysfunctions. PMID:24089642

  17. Indomethacin treatment reduces microglia activation and increases numbers of neuroblasts in the subventricular zone and ischaemic striatum after focal ischaemia.

    PubMed

    Lopes, Rosana S; Cardoso, Marcelo M; Sampaio, Arthur O; Barbosa, Mario Santos; Souza, Celice C; DA Silva, Michelle C; Ferreira, Elane Magno N; Freire, Marco Aurelio M; Lima, Rafael Rodrigues; Gomes-Leal, Walace

    2016-09-01

    Neuroblasts from the subventricular zone (SVZ) migrate to striatum following stroke, but most of them die in the ischaemic milieu and this can be related to exacerbated microglial activation. Here, we explored the effects of the non-steroidal anti-inflammatory indomethacin on microglial activation, neuronal preservation and neuroblast migration following experimental striatal stroke in adult rats. Animals were submitted to endothelin-1 (ET-1)-induced focal striatal ischaemia and were treated with indomethacin or sterile saline (i.p.) for 7 days, being perfused after 8 or 14 days. Immunohistochemistry was performed to assess neuronal loss (anti-NeuN), microglial activation (anti-Iba1, ED1) and migrating neuroblasts (anti-DCX) by counting NeuN, ED1 and DCX-positive cells in the ischaemic striatum or SVZ. Indomethacin treatment reduced microglia activation and the number of ED1+ cells in both 8 and 14 days post injury as compared with controls. There was an increase in the number of DCX+ cells in both SVZ and striatum at the same survival times. Moreover, there was a decrease in the number of NeuN+ cells in indomethacin-treated animals as compared with the control group at 8 days but not after 14 days post injury. Our results suggest that indomethacin treatment modulates microglia activation, contributing to increased neuroblast proliferation in the SVZ and migration to the ischaemic striatum following stroke. PMID:27581930

  18. Microglia retard dengue virus-induced acute viral encephalitis

    PubMed Central

    Tsai, Tsung-Ting; Chen, Chia-Ling; Lin, Yee-Shin; Chang, Chih-Peng; Tsai, Cheng-Chieh; Cheng, Yi-Lin; Huang, Chao-Ching; Ho, Chien-Jung; Lee, Yi-Chao; Lin, Liang-Tzung; Jhan, Ming-Kai; Lin, Chiou-Feng

    2016-01-01

    Patients with dengue virus (DENV) infection may also present acute viral encephalitis through an unknown mechanism. Here, we report that encephalitic DENV-infected mice exhibited progressive hunchback posture, limbic seizures, limbic weakness, paralysis, and lethality 7 days post-infection. These symptoms were accompanied by CNS inflammation, neurotoxicity, and blood-brain barrier destruction. Microglial cells surrounding the blood vessels and injured hippocampus regions were activated by DENV infection. Pharmacologically depleting microglia unexpectedly increased viral replication, neuropathy, and mortality in DENV-infected mice. In microglia-depleted mice, the DENV infection-mediated expression of antiviral cytokines and the infiltration of CD8-positive cytotoxic T lymphocytes (CTLs) was abolished. DENV infection prompted the antigen-presenting cell-like differentiation of microglia, which in turn stimulated CTL proliferation and activation. These results suggest that microglial cells play a key role in facilitating antiviral immune responses against DENV infection and acute viral encephalitis. PMID:27279150

  19. Microglia retard dengue virus-induced acute viral encephalitis.

    PubMed

    Tsai, Tsung-Ting; Chen, Chia-Ling; Lin, Yee-Shin; Chang, Chih-Peng; Tsai, Cheng-Chieh; Cheng, Yi-Lin; Huang, Chao-Ching; Ho, Chien-Jung; Lee, Yi-Chao; Lin, Liang-Tzung; Jhan, Ming-Kai; Lin, Chiou-Feng

    2016-01-01

    Patients with dengue virus (DENV) infection may also present acute viral encephalitis through an unknown mechanism. Here, we report that encephalitic DENV-infected mice exhibited progressive hunchback posture, limbic seizures, limbic weakness, paralysis, and lethality 7 days post-infection. These symptoms were accompanied by CNS inflammation, neurotoxicity, and blood-brain barrier destruction. Microglial cells surrounding the blood vessels and injured hippocampus regions were activated by DENV infection. Pharmacologically depleting microglia unexpectedly increased viral replication, neuropathy, and mortality in DENV-infected mice. In microglia-depleted mice, the DENV infection-mediated expression of antiviral cytokines and the infiltration of CD8-positive cytotoxic T lymphocytes (CTLs) was abolished. DENV infection prompted the antigen-presenting cell-like differentiation of microglia, which in turn stimulated CTL proliferation and activation. These results suggest that microglial cells play a key role in facilitating antiviral immune responses against DENV infection and acute viral encephalitis. PMID:27279150

  20. Activated Microglia-Induced Deficits in Excitatory Synapses Through IL-1β: Implications for Cognitive Impairment in Sepsis.

    PubMed

    Moraes, Carolina A; Santos, Gabriel; de Sampaio e Spohr, Tania Cristina Leite; D'Avila, Joana C; Lima, Flávia Regina Souza; Benjamim, Claudia Farias; Bozza, Fernando A; Gomes, Flávia Carvalho Alcantara

    2015-08-01

    Recent clinical studies have shown that sepsis survivors may develop long-term cognitive impairments. The cellular and molecular mechanisms involved in these events are not well understood. This study investigated synaptic deficits in sepsis and the involvement of glial cells in this process. Septic animals showed memory impairment and reduced numbers of hippocampal and cortical excitatory synapses, identified by synaptophysin/PSD-95 co-localization, 9 days after disease onset. The behavioral deficits and synaptophysin/PSD-95 co-localization were rescued to normal levels within 30 days post-sepsis. Septic mice presented activation of microglia and reactive astrogliosis, which are hallmarks of brain injury and could be involved in the associated synaptic deficits. We treated neuronal cultures with conditioned medium derived from cultured astrocytes (ACM) and microglia (MCM) that were either non-stimulated or stimulated with lipopolysaccharide (LPS) to investigate the molecular mechanisms underlying synaptic deficits in sepsis. ACM and MCM increased the number of synapses between cortical neurons in vitro, and these effects were antagonized by LPS stimulation. LPS-MCM reduced the number of synapses by 50%, but LPS-ACM increased the number of synapses by 500%. Analysis of the composition of these conditioned media revealed increased levels of IL-1β in LPS-MCM. Furthermore, inhibition of IL-1β signaling through the addition of a soluble IL-1β receptor antagonist (IL-1 Ra) fully prevented the synaptic deficit induced by LPS-MCM. These results suggest that sepsis induces a transient synaptic deficit associated with memory impairments mediated by IL-1β secreted by activated microglia. PMID:25257696

  1. Active Play Opportunities at Child Care

    PubMed Central

    Saelens, Brian E.; Christakis, Dimitri A.

    2015-01-01

    BACKGROUND AND OBJECTIVES: Physical activity (PA) is important for children’s health and development, yet preschoolers are not meeting PA recommendations. The objective of this study was to examine different PA opportunities at child care and how variation in indoor versus outdoor and free versus teacher-led opportunities relate to children’s PA. METHODS: An observational study of 98 children (mean age 4.5 years, 49% girls) from 10 child care centers. Classrooms were observed for at least 4 full days per center (total 50 days) to categorize time into (1) not an active play opportunity (APO); (2) naptime; (3) APO, outdoor free play; (4) APO, outdoor teacher-led; (5) APO, indoor free play; and (6) APO, indoor teacher-led. Children wore accelerometers during observations. Linear regression models examined the influence of APO categories on moderate-vigorous physical activity (MVPA) and sedentary time. RESULTS: Children’s activity was 73% sedentary, 13% light, and 14% MVPA. For 88% of time children did not have APOs, including 26% time as naptime. On average, 48 minutes per day were APOs (41% sedentary, 18% light, and 41% MVPA), 33 minutes per day were outdoors. The most frequent APO was outdoor free play (8% of time); outdoor teacher-led time was <1%. Children were more active and less sedentary outdoors versus indoors and during the child-initiated APOs (indoors and outdoors) versus teacher-led APOs. CONCLUSIONS: Preschoolers were presented with significantly fewer than recommended opportunities for PA at child care. More APOs are needed for children to meet recommendations, particularly those that encourage more outdoor time, more teacher-led and child-initiated active play, and flexibility in naptime for preschoolers. PMID:25986016

  2. World History Plays, Puzzles and Activities.

    ERIC Educational Resources Information Center

    Stevens, Lawrence

    This instructional resource, for grades 7-10, includes a collection of 10 plays with related learning activities. Units of study include: (1) "Alexander the Great and the Greeks"; (2) "The Black Death and the End of the Middle Ages"; (3) "Robert Clive and Imperialism"; (4) "Christopher Columbus and the Age of Exploration"; (5) "Fall of the…

  3. JAK2-STAT3 signaling pathway mediates thrombin-induced proinflammatory actions of microglia in vitro.

    PubMed

    Huang, Chengfang; Ma, Rong; Sun, Shenggang; Wei, Guirong; Fang, Yuan; Liu, Rengang; Li, Gang

    2008-11-15

    The present study shows that JAK2-STAT3 inflammatory signaling mediates thrombin-stimulated microglia activation. In rat primary microglia, thrombin rapidly activated JAK2 and induced phosphorylation of STAT3. In addition, thrombin increased transcription of the inflammation-associated genes tumor necrosis factor (TNF)-alpha, inducible nitric oxide synthase (iNOS), production of TNF-alpha, NO and induced neurodegeneration of dopaminergic neurons in mesencephalic cultures. AG490, a JAK inhibitor, markedly reduced activation of JAK2 and STAT3 in thrombin-treated microglia. AG490 also inhibited thrombin-induced transcription and expression of TNF-alpha, iNOS and/or NO release, moreover rescued dopaminergic neurons. These results suggest that JAK2-STAT3 signaling pathway plays a critical role in mediating thrombin-induced activation of microglia and degeneration of dopaminergic neurons. PMID:18710787

  4. Effects of F/G-actin ratio and actin turn-over rate on NADPH oxidase activity in microglia

    PubMed Central

    2010-01-01

    Background Most in vivo studies that have addressed the role of actin dynamics in NADPH oxidase function in phagocytes have used toxins to modulate the polymerization state of actin and mostly effects on actin has been evaluated by end point measurements of filamentous actin, which says little about actin dynamics, and without consideration for the subcellular distribution of the perturbed actin cytoskeleton. Results Here, we in addition to toxins use conditional expression of the major actin regulatory protein LIM kinase-1 (LIMK1), and shRNA knock-down of cofilin to modulate the cellular F/G-actin ratio in the Ra2 microglia cell line, and we use Fluorescence Recovery after Photobleaching (FRAP) in β-actin-YFP-transduced cells to obtain a dynamic measure of actin recovery rates (actin turn-over rates) in different F/G-actin states of the actin cytoskeleton. Our data demonstrate that stimulated NADPH oxidase function was severely impaired only at extreme actin recovery rates and F/G-actin ratios, and surprisingly, that any moderate changes of these parameters of the actin cytoskeleton invariably resulted in an increased NADPH oxidase activity. Conclusion moderate actin polymerization and depolymerization both increase the FMLP and PMA-stimulated NADPH oxidase activity of microglia, which is directly correlated with neither actin recovery rate nor F/G- actin ratio. Our results indicate that NADPH oxidase functions in an enhanced state of activity in stimulated phagocytes despite widely different states of the actin cytoskeleton. PMID:20825680

  5. How microglia kill neurons.

    PubMed

    Brown, Guy C; Vilalta, Anna

    2015-12-01

    Microglia are resident brain macrophages that become inflammatory activated in most brain pathologies. Microglia normally protect neurons, but may accidentally kill neurons when attempting to limit infections or damage, and this may be more common with degenerative disease as there was no significant selection pressure on the aged brain in the past. A number of mechanisms by which activated microglia kill neurons have been identified, including: (i) stimulation of the phagocyte NADPH oxidase (PHOX) to produce superoxide and derivative oxidants, (ii) expression of inducible nitric oxide synthase (iNOS) producing NO and derivative oxidants, (iii) release of glutamate and glutaminase, (iv) release of TNFα, (v) release of cathepsin B, (vi) phagocytosis of stressed neurons, and (vii) decreased release of nutritive BDNF and IGF-1. PHOX stimulation contributes to microglial activation, but is not directly neurotoxic unless NO is present. NO is normally neuroprotective, but can react with superoxide to produce neurotoxic peroxynitrite, or in the presence of hypoxia inhibit mitochondrial respiration. Glutamate can be released by glia or neurons, but is neurotoxic only if the neurons are depolarised, for example as a result of mitochondrial inhibition. TNFα is normally neuroprotective, but can become toxic if caspase-8 or NF-κB activation are inhibited. If the above mechanisms do not kill neurons, they may still stress the neurons sufficiently to make them susceptible to phagocytosis by activated microglia. We review here whether microglial killing of neurons is an artefact, makes evolutionary sense or contributes in common neuropathologies and by what mechanisms. This article is part of a Special Issue entitled SI: Neuroprotection. PMID:26341532

  6. Neuroprotective effect of endogenous cannabinoids on ischemic brain injury induced by the excess microglia-mediated inflammation

    PubMed Central

    Guo, Shuyun; Liu, Yanwu; Ma, Rui; Li, Jun; Su, Binxiao

    2016-01-01

    Increasing evidence has demonstrated the role of endogenous cannabinoids system (ECS) on protecting brain injury caused by ischemia (IMI). Papers reported that microglia-mediated inflammation has become one of the most pivotal mechanisms for IMI. This study was aimed to investigate the potential roles of ECS on neuron protection under microglia-mediated inflammation. Inflammatory cytokines level both in vitro (BV-2 cells) and in vivo (brain tissue from constructed IMI model and brain-isolated microglia) was detected. ECS levels were detected, and its effects on inflammations was also analyzed. Influence of microglia-mediated inflammation on neuron injury was analyzed. Moreover, the effects of ECS on protecting neuron injury were also analyzed. Our results showed that the levels of inflammatory cytokines including TNFα and IL-1β were higher while IKBα was lower in IMI model brain tissue, brain-isolated microglia and BV-2 cells compared to the control. Inflammation was activated in microglia, as well as the activation of ECS characterized by the increasing level of AEA and 2-AG. Furthermore, the activated microglia-mediated self-inflammation performed harmful influence on neurons via suppressing cell viability and inducing apoptosis. Moreover, ECS functioned as a protector on neuron injury though promoting cell proliferation and suppressing cell apoptosis which were caused by the activated BV-2 cells (LPS induced for 3 h). Our data suggested that ECS may play certain neuroprotective effects on microglia-mediated inflammations-induced IMI through anti-inflammatory function. PMID:27398146

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

    PubMed Central

    Ribeiro Xavier, Anna L.; Kress, Benjamin T.; Goldman, Steven A.; Lacerda de Menezes, João R.

    2015-01-01

    Microglia are involved in synaptic pruning both in development and in the mature CNS. In this study, we investigated whether microglia might further contribute to circuit plasticity by modulating neuronal recruitment from the neurogenic subventricular zone (SVZ) of the adult mouse striatum. We 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 expression of purinoceptors and lack of ATP-elicitable chemotaxis. Furthermore, the in vivo depletion of these microglia hampered the survival and migration of newly generated neuroblasts through the RMS to the olfactory bulb. SVZ and RMS microglia thus appear to comprise a functionally distinct class that is selectively adapted to the support and direction of neuronal integration into the olfactory circuitry. Therefore, this unique microglial subpopulation may serve as a novel target with which to modulate cellular addition from endogenous neural stem and progenitor cells of the adult brain. SIGNIFICANCE 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 circuitry sculpture. Here, we addressed microglial functions in the subventricular zone (SVZ), the major postnatal neurogenic niche. Our results depict microglia as a conspicuous component of SVZ and its anterior extension, the rostral migratory stream, a pathway used by neuroblasts during their transit toward olfactory bulb layers. In addition to other unique populations residing in the SVZ niche, microglia display distinct morphofunctional properties that boost neuronal

  8. Microglia and inflammation: conspiracy, controversy or control?

    PubMed

    Fernandes, Adelaide; Miller-Fleming, Leonor; Pais, Teresa F

    2014-10-01

    Microglial cells contribute to normal function of the central nervous system (CNS). Besides playing a role in the innate immunity, they are also involved in neuronal plasticity and homeostasis of the CNS. While microglial cells get activated and undergo phenotypic changes in different disease contexts, they are far from being the "villains" in the CNS. Mounting evidence indicates that microglial dysfunction can exacerbate the pathogenesis of several diseases in the CNS. Several molecular mechanisms tightly regulate the production of inflammatory and toxic factors released by microglia. These mechanisms involve the interaction with other glial cells and neurons and the fine regulation of signaling and transcription activation pathways. The purpose of this review is to discuss microglia activation and to highlight the molecular pathways that can counteract the detrimental role of microglia in several neurologic diseases. Recent work presented in this review support that the understanding of microglial responses can pave the way to design new therapies for inflammatory diseases of the CNS. PMID:25008043

  9. NLRP3 Inflammasome Is Expressed and Functional in Mouse Brain Microglia but Not in Astrocytes

    PubMed Central

    Gustin, Audrey; Kirchmeyer, Mélanie; Koncina, Eric; Felten, Paul; Losciuto, Sophie; Heurtaux, Tony; Tardivel, Aubry; Heuschling, Paul; Dostert, Catherine

    2015-01-01

    Neuroinflammation is the local reaction of the brain to infection, trauma, toxic molecules or protein aggregates. The brain resident macrophages, microglia, are able to trigger an appropriate response involving secretion of cytokines and chemokines, resulting in the activation of astrocytes and recruitment of peripheral immune cells. IL-1β plays an important role in this response; yet its production and mode of action in the brain are not fully understood and its precise implication in neurodegenerative diseases needs further characterization. Our results indicate that the capacity to form a functional NLRP3 inflammasome and secretion of IL-1β is limited to the microglial compartment in the mouse brain. We were not able to observe IL-1β secretion from astrocytes, nor do they express all NLRP3 inflammasome components. Microglia were able to produce IL-1β in response to different classical inflammasome activators, such as ATP, Nigericin or Alum. Similarly, microglia secreted IL-18 and IL-1α, two other inflammasome-linked pro-inflammatory factors. Cell stimulation with α-synuclein, a neurodegenerative disease-related peptide, did not result in the release of active IL-1β by microglia, despite a weak pro-inflammatory effect. Amyloid-β peptides were able to activate the NLRP3 inflammasome in microglia and IL-1β secretion occurred in a P2X7 receptor-independent manner. Thus microglia-dependent inflammasome activation can play an important role in the brain and especially in neuroinflammatory conditions. PMID:26091541

  10. Raf-kinase inhibitor protein attenuates microglia inflammation in an in vitro model of intracerebral hemorrhage.

    PubMed

    Wang, J; Du, J; Miao, C; Lian, H

    2016-01-01

    Microglia mediated neuroinflammation plays a crucial role in intracerebral hemorrhage (ICH). Raf kinase inhibitor protein (RKIP), a member of the phosphatidylethanolamine-binding protein (PEBP) family, is a negative regulator of inflammatory responses. However, the expression and anti-inflammatory effects of RKIP in microglia after ICH have not been reported. Therefore, in the current study, we investigated the effects of RKIP on inflammatory responses in erythrocyte lysate-treated BV2 microglia. Furthermore, we analyzed the detailed molecular mechanisms underlying the anti-inflammatory effects of RKIP in microglia. Our results showed that the expression level of RKIP was significantly decreased by erythrocyte lysate treatment in BV2 microglia. Overexpression of RKIP inhibited the production of pro-inflammatory molecules. In addition, overexpression of RKIP attenuated neuronal cell death induced by activated microglia. Moreover, RKIP suppressed the activation of NF-κB signaling pathway in erythrocyte lysis-treated BV2 cells. In conclusion, these data suggest that overexpression of RKIP attenuated microglia inflammation through inhibiting the NF-κB signaling pathway in erythrocyte lysis-treated BV2 cells. The present study provides evidence that RKIP may be used as an effective molecular target for the treatment of ICH. PMID:27262809

  11. Expression and Contributions of TRPM7 and KCa2.3/SK3 Channels to the Increased Migration and Invasion of Microglia in Anti-Inflammatory Activation States

    PubMed Central

    Ferreira, Roger; Wong, Raymond; Schlichter, Lyanne C.

    2014-01-01

    Microglia rapidly respond to CNS injury and disease and can assume a spectrum of activation states. While changes in gene expression and production of inflammatory mediators have been extensively described after classical (LPS-induced) and alternative (IL4-induced) microglial activation, less is known about acquired de-activation in response to IL10. It is important to understand how microglial activation states affect their migration and invasion; crucial functions after injury and in the developing CNS. We reported that LPS-treated rat microglia migrate very poorly, while IL4-treated cells migrate and invade much better. Having discovered that the lamellum of migrating microglia contains a large ring of podosomes – microscopic structures that are thought to mediate adhesion, migration and invasion – we hypothesized that IL4 and IL10 would differentially affect podosome expression, gene induction, migration and invasion. Further, based on the enrichment of the KCa2.3/SK3 Ca2+-activated potassium channel in microglial podosomes, we predicted that it regulates migration and invasion. We found both similarities and differences in gene induction by IL4 and IL10 and, while both cytokines increased migration and invasion, only IL10 affected podosome expression. KCa2.3 currents were recorded in microglia under all three activation conditions and KCNN3 (KCa2.3) expression was similar. Surprisingly then, of three KCa2.3 inhibitors (apamin, tamapin, NS8593), only NS8593 abrogated the increased migration and invasion of IL4 and IL10-treated microglia (and invasion of unstimulated microglia). This discrepancy was explained by the observed block of TRPM7 currents in microglia by NS8593, which occurred under all three activation conditions. A similar inhibition of both migration and invasion was seen with a TRPM7 inhibitor (AA-861) that does not block KCa2.3 channels. Thus, we conclude that TRPM7 (not KCa2.3) contributes to the enhanced ability of microglia to migrate and

  12. Bioaccessible (poly)phenol metabolites from raspberry protect neural cells from oxidative stress and attenuate microglia activation.

    PubMed

    Garcia, Gonçalo; Nanni, Sara; Figueira, Inês; Ivanov, Ines; McDougall, Gordon J; Stewart, Derek; Ferreira, Ricardo B; Pinto, Paula; Silva, Rui F M; Brites, Dora; Santos, Cláudia N

    2017-01-15

    Neuroinflammation is an integral part of the neurodegeneration process inherent to several aging dysfunctions. Within the central nervous system, microglia are the effective immune cells, responsible for neuroinflammatory responses. In this study, raspberries were subjected to in vitro digestion simulation to obtain the components that result from the gastrointestinal (GI) conditions, which would be bioaccessible and available for blood uptake. Both the original raspberry extract and the gastrointestinal bioaccessible (GIB) fraction protected neuronal and microglia cells against H2O2-induced oxidative stress and lipopolysaccharide (LPS)-induced inflammation, at low concentrations. Furthermore, this neuroprotective capacity was independent of intracellular ROS scavenging mechanisms. We show for the first time that raspberry metabolites present in the GIB fraction significantly inhibited microglial pro-inflammatory activation by LPS, through the inhibition of Iba1 expression, TNF-α release and NO production. Altogether, this study reveals that raspberry polyphenols may present a dietary route to the retardation or amelioration of neurodegenerative-related dysfunctions. PMID:27542476

  13. Prenatal immune activation in mice blocks the effects of environmental enrichment on exploratory behavior and microglia density.

    PubMed

    Buschert, Jens; Sakalem, Marna E; Saffari, Roja; Hohoff, Christa; Rothermundt, Matthias; Arolt, Volker; Zhang, Weiqi; Ambrée, Oliver

    2016-06-01

    Adverse environmental factors including prenatal maternal infection are capable of inducing long-lasting behavioral and neural alterations which can enhance the risk to develop schizophrenia. It is so far not clear whether supportive postnatal environments are able to modify such prenatally-induced alterations. In rodent models, environmental enrichment influences behavior and cognition, for instance by affecting endocrinologic, immunologic, and neuroplastic parameters. The current study was designed to elucidate the influence of postnatal environmental enrichment on schizophrenia-like behavioral alterations induced by prenatal polyI:C immune stimulation at gestational day 9 in mice. Adult offspring were tested for amphetamine-induced locomotion, social interaction, and problem-solving behavior as well as expression of dopamine D1 and D2 receptors and associated molecules, microglia density and adult neurogenesis. Prenatal polyI:C treatment resulted in increased dopamine sensitivity and dopamine D2 receptor expression in adult offspring which was not reversed by environmental enrichment. Prenatal immune activation prevented the effects of environmental enrichment which increased exploratory behavior and microglia density in NaCl treated mice. Problem-solving behavior as well as the number of immature neurons was affected by neither prenatal immune stimulation nor postnatal environmental enrichment. The behavioral and neural alterations that persist into adulthood could not generally be modified by environmental enrichment. This might be due to early neurodevelopmental disturbances which could not be rescued or compensated for at a later developmental stage. PMID:26776071

  14. Differential effects of ginsenosides on NO and TNF-alpha production by LPS-activated N9 microglia.

    PubMed

    Wu, Chun Fu; Bi, Xiu Li; Yang, Jing Yu; Zhan, Jia Yang; Dong, Ying Xu; Wang, Jin Hui; Wang, Ji Ming; Zhang, Ruiwen; Li, Xian

    2007-03-01

    Ginsenosides, the main active components of ginseng, have been reported to exert neuroprotective effects in the central nervous system. In this report, the effects of ginsenoside-Rd and -Rb2, two protopanaxadiols, and ginsenoside-Rg1 and -Re, two protopanaxatriols, on the production of nitric oxide (NO) and TNF-alpha (TNF-alpha) by lipopolysaccharide (LPS)-activated N9 microglial cells were studied. All ginsenosides studied potently suppressed TNF-alpha production in LPS-activated N9 cells. Ginsenoside-Rg1 and -Re, but not ginsenoside-Rb2 and -Rd, inhibited the production of NO in LPS-activated N9 cells. Ginsenosides inhibited the phosphorylation of c-Jun NH2-terminal kinase (JNK), c-Jun and extracellular signal-regulated kinase (ERK), The findings herein show that the inhibition of LPS-induced ERK1/2 and JNK activation may be a contributing factor to the main mechanisms by which ginsenosides inhibits RAW264.7. To clarify the mechanistic basis for its ability to inhibit TNF-alpha and NO induction, the effect of ginsenosides on transcription factor NF-kappaB protein level was also examined. These activities were associated with the down-regulation of inhibitor kappaB (IkappaB). These findings suggest that the inhibition of LPS-induced NO formation and TNF-alpha production in microglia by ginsenosides is due to its inhibition of NF-kappaB, which may be the mechanistic basis for the anti-inflammatory effects of ginsenosides. The significant suppressive effects of ginsenosides on proinflammatory responses of microglia implicate their therapeutic potential in neurodegenerative diseases accompanied by microglial activation. PMID:17276889

  15. Overexpression of Heat Shock Protein 72 Attenuates NF-κB Activation Using a Combination of Regulatory Mechanisms in Microglia

    PubMed Central

    Khammash, Mustafa; Giffard, Rona G.

    2014-01-01

    Overexpression of the inducible heat shock protein 70, Hsp72, has broadly cytoprotective effects and improves outcome following stroke. A full understanding of how Hsp72 protects cells against injury is elusive, though several distinct mechanisms are implicated. One mechanism is its anti-inflammatory effects. We study the effects of Hsp72 overexpression on activation of the transcription factor NF-κB in microglia combining experimentation and mathematical modeling, using TNFα to stimulate a microglial cell line stably overexpressing Hsp72. We find that Hsp72 overexpression reduces the amount of NF-κB DNA binding activity, activity of the upstream kinase IKK, and amount of IκBα inhibitor phosphorylated following TNFα application. Simulations evaluating several proposed mechanisms suggest that inhibition of IKK activation is an essential component of its regulatory activities. Unexpectedly we find that Hsp72 overexpression reduces the initial amount of the RelA/p65 NF-κB subunit in cells, contributing to the attenuated response. Neither mechanism in isolation, however, is sufficient to attenuate the response, providing evidence that Hsp72 relies upon multiple mechanisms to attenuate NF-κB activation. An additional observation from our study is that the induced expression of IκBα is altered significantly in Hsp72 expressing cells. While the mechanism responsible for this observation is not known, it points to yet another means by which Hsp72 may alter the NF-κB response. This study illustrates the multi-faceted nature of Hsp72 regulation of NF-κB activation in microglia and offers further clues to a novel mechanism by which Hsp72 may protect cells against injury. PMID:24516376

  16. Minocycline attenuates post-operative cognitive impairment in aged mice by inhibiting microglia activation.

    PubMed

    Wang, Hui-Lin; Liu, Hua; Xue, Zhang-Gang; Liao, Qing-Wu; Fang, Hao

    2016-09-01

    Although it is known that isoflurane exposure or surgery leads to post-operative cognitive dysfunction in aged rodents, there are few clinical interventions and treatments available to prevent this disorder. Minocycline (MINO) produces neuroprotection from several neurodegenerative diseases and various experimental animal models. Therefore, we set out to investigate the effects of MINO pre-treatment on isoflurane or surgery induced cognitive impairment in aged mice by assessing the hippocampal-dependent spatial memory performance using the Morris water maze task. Hippocampal tissues were isolated from mice and evaluated by Western blot analysis, immunofluorescence procedures and protein array system. Our results elucidate that MINO down-regulated the isoflurane-induced and surgery-induced enhancement in the protein levels of pro-inflammatory cytokine tumour necrosis factor alpha, interleukin (IL)-1β, interferon-γ and microglia marker Iba-1, and up-regulated protein levels of the anti-inflammatory cytokine IL-4 and IL-10. These findings suggest that pre-treatment with MINO attenuated isoflurane or surgery induced cognitive impairment by inhibiting the overactivation of microglia in aged mice. PMID:27061744

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

    SciTech Connect

    Park, Hye Young; Kim, Nam Deuk; Kim, Gi-Young; Hwang, Hye Jin; Kim, Byung-Woo; Kim, Wun Jae; Choi, Yung Hyun

    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.

  18. Spreading Depression Requires Microglia and is Decreased by their M2a Polarization from Environmental Enrichment

    PubMed Central

    Pusic, Kae M.; Pusic, Aya D.; Kemme, Jordan; Kraig, Richard P.

    2014-01-01

    Microglia play an important role in fine-tuning neuronal activity. In part, this involves their production of tumor necrosis factor alpha (TNFα), which increases neuronal excitability. Excessive synaptic activity is necessary to initiate spreading depression (SD). Increased microglial production of pro-inflammatory cytokines promotes initiation of SD, which, when recurrent, may play a role in conversion of episodic to high frequency and chronic migraine. Previous work shows that this potentiation of SD occurs through increased microglial production of TNFα and reactive oxygen species, both of which are associated with an M1-skewed microglial population. Hence, we explored the role of microglia and their M1 polarization in SD initiation. Selective ablation of microglia from rat hippocampal slice cultures confirmed that microglia are essential for initiation of SD. Application of minocycline to dampen M1 signaling led to increased SD threshold. In addition, we found that SD threshold was increased in rats exposed to environmental enrichment. These rats had increased neocortical levels of interleukin-11 (IL-11), which decreases TNFα signaling and polarized microglia to an M2a-dominant phenotype. M2a microglia reduce pro-inflammatory signaling and increase production of anti-inflammatory cytokines, and therefore may protect against SD. Nasal administration of IL-11 to mimic effects of environmental enrichment likewise increased M2a polarization and increased SD threshold, an effect also seen in vitro. Similarly, application of conditioned medium from M2a polarized primary microglia to slice cultures also increased SD threshold. Thus, microglia and their polarization state play an essential role in SD initiation, and perhaps by extension migraine with aura and migraine. PMID:24723305

  19. Microglia in ischemic brain injury

    PubMed Central

    Weinstein, Jonathan R; Koerner, Ines P; Möller, Thomas

    2010-01-01

    Microglia are resident CNS immune cells that are active sensors in healthy brain and versatile effectors under pathological conditions. Cerebral ischemia induces a robust neuroinflammatory response that includes marked changes in the gene-expression profile and phenotype of a variety of endogenous CNS cell types (astrocytes, neurons and microglia), as well as an influx of leukocytic cells (neutrophils, macrophages and T-cells) from the periphery. Many molecules and conditions can trigger a transformation of surveying microglia to microglia of an alerted or reactive state. Here we review recent developments in the literature that relate to microglial activation in the experimental setting of in vitro and in vivo ischemia. We also present new data from our own laboratory demonstrating the direct effects of in vitro ischemic conditions on the microglial phenotype and genomic profile. In particular, we focus on the role of specific molecular signaling systems, such as hypoxia inducible factor-1 and Toll-like receptor-4, in regulating the microglial response in this setting. We then review histological and novel radiological data that confirm a key role for microglial activation in the setting of ischemic stroke in humans. We also discuss recent progress in the pharmacologic and molecular targeting of microglia in acute ischemic stroke. Finally, we explore how recent studies on ischemic preconditioning have increased interest in pre-emptively targeting microglial activation in order to reduce stroke severity. PMID:20401171

  20. Activated microglia mediate synapse loss and short-term memory deficits in a mouse model of transthyretin-related oculoleptomeningeal amyloidosis.

    PubMed

    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

    2013-01-01

    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. PMID:24008733

  1. Walnut extract inhibits LPS-induced activation of BV-2 microglia via internalization of TLR4: possible involvement of phospholipase D2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Walnuts are a rich source of essential fatty acids, including the polyunsaturated fatty acids alpha-linolenic acid (ALA) and linoleic acid (LA). Essential fatty acids have been shown to modulate a number of cellular processes in the brain, including the activation state of microglia. Microglial acti...

  2. Probucol inhibits LPS-induced microglia activation and ameliorates brain ischemic injury in normal and hyperlipidemic mice

    PubMed Central

    Jung, Yeon Suk; Park, Jung Hwa; Kim, Hyunha; Kim, So Young; Hwang, Ji Young; Hong, Ki Whan; Bae, Sun Sik; Choi, Byung Tae; Lee, Sae-Won; Shin, Hwa Kyoung

    2016-01-01

    Aim: Increasing evidence suggests that probucol, a lipid-lowering agent with anti-oxidant activities, may be useful for the treatment of ischemic stroke with hyperlipidemia via reduction in cholesterol and neuroinflammation. In this study we examined whether probucol could protect against brain ischemic injury via anti-neuroinflammatory action in normal and hyperlipidemic mice. Methods: Primary mouse microglia and murine BV2 microglia were exposed to lipopolysaccharide (LPS) for 3 h, and the release NO, PGE2, IL-1β and IL-6, as well as the changes in NF-κB, MAPK and AP-1 signaling pathways were assessed. ApoE KO mice were fed a high-fat diet containing 0.004%, 0.02%, 0.1% (wt/wt) probucol for 10 weeks, whereas normal C57BL/6J mice received probucol (3, 10, 30 mg·kg-1·d-1, po) for 4 d. Then all the mice were subjected to focal cerebral ischemia through middle cerebral artery occlusion (MCAO). The neurological deficits were scored 24 h after the surgery, and then brains were removed for measuring the cerebral infarct size and the production of pro-inflammatory mediators. Results: In LPS-treated BV2 cells and primary microglial cells, pretreatment with probucol (1, 5, 10 μmol/L) dose-dependently inhibited the release of NO, PGE2, IL-1β and IL-6, which occurred at the transcription levels. Furthermore, the inhibitory actions of probucol were associated with the downregulation of the NF-κB, MAPK and AP-1 signaling pathways. In the normal mice with MCAO, pre-administration of probucol dose-dependently decreased the infarct volume and improved neurological function. These effects were accompanied by the decreased production of pro-inflammatory mediators (iNOS, COX-2, IL-1, IL-6). In ApoE KO mice fed a high-fat diet, pre-administration of 0.1% probucol significantly reduced the infarct volume, improved the neurological deficits following MCAO, and decreased the total- and LDL-cholesterol levels. Conclusion: Probucol inhibits LPS-induced microglia activation and

  3. Dark microglia: A new phenotype predominantly associated with pathological states.

    PubMed

    Bisht, Kanchan; Sharma, Kaushik P; Lecours, Cynthia; Sánchez, Maria Gabriela; El Hajj, Hassan; Milior, Giampaolo; Olmos-Alonso, Adrián; Gómez-Nicola, Diego; Luheshi, Giamal; Vallières, Luc; Branchi, Igor; Maggi, Laura; Limatola, Cristina; Butovsky, Oleg; Tremblay, Marie-Ève

    2016-05-01

    The past decade has witnessed a revolution in our understanding of microglia. These immune cells were shown to actively remodel neuronal circuits, leading to propose new pathogenic mechanisms. To study microglial implication in the loss of synapses, the best pathological correlate of cognitive decline across chronic stress, aging, and diseases, we recently conducted ultrastructural analyses. Our work uncovered the existence of a new microglial phenotype that is rarely present under steady state conditions, in hippocampus, cerebral cortex, amygdala, and hypothalamus, but becomes abundant during chronic stress, aging, fractalkine signaling deficiency (CX3 CR1 knockout mice), and Alzheimer's disease pathology (APP-PS1 mice). Even though these cells display ultrastructural features of microglia, they are strikingly distinct from the other phenotypes described so far at the ultrastructural level. They exhibit several signs of oxidative stress, including a condensed, electron-dense cytoplasm and nucleoplasm making them as "dark" as mitochondria, accompanied by a pronounced remodeling of their nuclear chromatin. Dark microglia appear to be much more active than the normal microglia, reaching for synaptic clefts, while extensively encircling axon terminals and dendritic spines with their highly ramified and thin processes. They stain for the myeloid cell markers IBA1 and GFP (in CX3 CR1-GFP mice), and strongly express CD11b and microglia-specific 4D4 in their processes encircling synaptic elements, and TREM2 when they associate with amyloid plaques. Overall, these findings suggest that dark microglia, a new phenotype that we identified based on their unique properties, could play a significant role in the pathological remodeling of neuronal circuits, especially at synapses. PMID:26847266

  4. Amyloid-β(1-42) protofibrils formed in modified artificial cerebrospinal fluid bind and activate microglia.

    PubMed

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

    2013-03-01

    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. Involvement of nitric oxide through endocannabinoids release in microglia activation during the course of CNS regeneration in the medicinal leech.

    PubMed

    Arafah, Karim; Croix, Dominique; Vizioli, Jacopo; Desmons, Annie; Fournier, Isabelle; Salzet, Michel

    2013-04-01

    The medicinal leech is notable for its capacity to regenerate its central nervous system (CNS) following mechanical trauma. Using an electrochemical nitric oxide (NO)-selective electrode to measure NO levels, we found that the time course of NO release in the injured leech CNS is partially under the control of endocannabinoids, namely, N-arachidonyl ethanolamide (AEA) and 2-arachidonyl glycerol (2-AG). Relative quantification of these endocannabinoids was performed by stable isotope dilution (2AGd8 and AAEd8) coupled to mass spectrometry in course of regeneration process or adenosine triphosphate (ATP) treatment. Data show that 2-AG levels rose to a maximum about 30 min after injury or ATP treatment, and returned to baseline levels 4 h after injury. In same conditions, AEA levels also rapidly (within 5 min) dropped after injury or ATP treatment to the nerve cord, but did not fully return to baseline levels within 4 h of injury. In correlation with these data, chemoattraction activities of endocannabinoids on isolated leech microglial cells have been shown in vitro and in vivo reflecting that control over NO production is accompanied by the controlled chemoattraction of microglia directed from the periphery to the lesion site for neuronal repair purposes. Taken together, our results show that in the leech, after injury concurrent with ATP production, purinergic receptor activation, NO production, microglia recruitment, and accumulation to lesion site, a fine imbalance occurs in the endocannabinoid system. These events can bring explanations about the ability of the leech CNS to regenerate after a trauma and the key role of endocannabinoids in this phenomenon. PMID:23355252

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

    PubMed Central

    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

  7. Immediate and Ultimate Functions of Physical Activity Play.

    ERIC Educational Resources Information Center

    McCune, Lorraine

    1998-01-01

    Play has been difficult to define because it is an aspect of many activities rather than of just a specific kind of activity. Classic theorists such as Piaget and Vygotsky emphasized representational play as play in its purist form, but both immediate and ultimate functions of play can be discerned in simple physical activity play. (Author)

  8. Play.

    ERIC Educational Resources Information Center

    Rogers, Fred; Sharapan, Hedda

    1993-01-01

    Contends that, in childhood, work and play seem to come together. Says that for young children their play is their work, and the more adults encourage children to play, the more they emphasize important lifelong resource. Examines some uses of children's play, making and building, artwork, dramatic play, monsters and superheroes, gun play, and…

  9. Microglia replenished OHSC: A culture system to study in vivo like adult microglia.

    PubMed

    Masuch, Annette; van der Pijl, Rianne; Füner, Lisa; Wolf, Yochai; Eggen, Bart; Boddeke, Erik; Biber, Knut

    2016-08-01

    Recent data suggest that ramified microglia fulfil various tasks in the brain. However, to investigate this unique cell type cultured primary microglia are only a poor model. We here describe a method to deplete and repopulate organotypic hippocampal slice cultures (OHSC) with ramified microglia isolated from adult mouse brain creating microglia-replenished OHSC (Mrep-OHSC). Replenished microglia integrate into the tissue and ramify to a degree indistinguishable from their counterparts in the mouse brain. Moreover, wild-type slices replenished with microglia from TNFα-deficient animals provide similar results as OHSC prepared from microglia-specific TNFα-knockout mice (CX3CR1(cre) /TNFα(fl/fl) ). Furthermore, this study demonstrates that replenished microglia in OHSC maintain original functions and properties acquired in vivo. Microglia from ERCC1(Δ/ko) mice, a mouse model of accelerated aging, maintain enhanced Mac2 expression and their activated phenotype after replenishment to wild-type OHSC tissue. Thus, the present study demonstrates that Mrep-OHSC are a unique tool to construct chimeric brain slices allowing studying the function of different phenotypes of in vivo like microglia in a tissue culture setting. GLIA 2016 GLIA 2016;64:1285-1297. PMID:27145902

  10. Inflammation, Microglia and Alzheimer's Disease

    PubMed Central

    Cameron, Brent; Landreth, Gary E.

    2009-01-01

    Microglia are the brain's tissue macrophage and representative of the innate immune system. These cells normally provide tissue maintenance and immune surveillance of the brain. In the Alzheimer's disease brain amyloid deposition provokes the phenotypic activation of microglia and their elaboration of proinflammatory molecules. Recent work has implicated Toll-like receptors in microglial recognition and response to amyloid fibrils. It is now evident that these cells exhibit more complex and heterogeneous phenotypes than previously appreciated that reflect both the plasticity of cells in this lineage and their ability to transition between activation states. The phenotypic diversity is associated with inactivation of the inflammatory response and tissue repair. We discuss recent evidence that the brain can be infiltrated by circulating monocytes in the diseased brain and that these cells may comprise a unique subpopulation of myeloid cells that may be functionally distinct from the endogenous microglia. PMID:19833208

  11. 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.

    PubMed

    Yang, Chongfei; Yu, Lifeng; Kong, Lingbo; Ma, Rui; Zhang, Juliang; Zhu, Qingsheng; Zhu, Jinyu; Hao, Dingjun

    2014-01-01

    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. PMID:25314304

  12. Learning To Play, Playing To Learn. Games and Activities To Teach Sharing, Caring, and Compromise.

    ERIC Educational Resources Information Center

    Steffens, Charlie; Gorin, Spencer

    This book demonstrates that therapeutic play can provide a solution to contemporary socialization problems. It provides a selection of games and activities that teach children about living in the world through the dynamics of play. Section 1, "Introduction," defines "play" and the philosophy and rules behind a healthy play program. Section 2,…

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

    SciTech Connect

    Fanarraga, M.L.

    2009-02-01

    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.

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

    PubMed Central

    Kato, Takahiro A.; Kanba, Shigenobu

    2013-01-01

    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 the normal brain, have defied the common traditional belief that microglia do not contribute 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. PMID:23443737

  15. Nutrients, Microglia Aging, and Brain Aging

    PubMed Central

    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. PMID:26941889

  16. Gamma-decanolactone inhibits iNOS and TNF-alpha production by lipopolysaccharide-activated microglia in N9 cells.

    PubMed

    Pflüger, Pricila; Viau, Cassiana Macagnan; Coelho, Vanessa Rodrigues; Berwig, Natália Alice; Staub, Renata Bartolomeu; Pereira, Patrícia; Saffi, Jenifer

    2016-06-01

    Activated microglia that produce reactive nitrogen species (RNS), inflammatory factors, reactive oxygen species (ROS), and other neurovirulent factors may lead to the development of neurodegenerative diseases. Certain compounds can inhibit the activation of microglia. However, these mechanisms remain unclear. In the present study, we investigated the inhibitory effect of Gamma-decanolactone (GD) on the production of reactive oxygen species and inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS) - stimulated N9 murine microglial cells through the p38 MAPK signaling pathway. The results showed that GD attenuated the activation of N9 cells and inhibited intracellular reactive oxygen species and the expression of iNOS and TNF-α induced by LPS in the cells. In addition, GD blocked the phosphorylation of p38 and inhibited cleaved caspase-9 and DNA damage. These data indicate that GD has therapeutic potential for the treatment of neurodegenerative diseases, and that it exerts its effects by inhibiting inflammation. PMID:27012990

  17. 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

    PubMed Central

    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

  18. Characterization of a SILAC method for proteomic analysis of primary rat microglia

    PubMed Central

    Zhang, Ping; Culver-Cochran, Ashley E.; Stevens, Stanley M.; Liu, Bin

    2016-01-01

    Microglia play important and dynamic roles in mediating a variety of physiological and pathological processes during the development, normal function and degeneration of the central nervous system. Application of SILAC-based proteomic analysis would greatly facilitate the identification of cellular pathways regulating the multifaceted phenotypes of microglia. We and others have successfully SILAC-labeled immortalized murine microglial cell lines in previous studies. In this study, we report the development and evaluation of a SILAC-labeled primary rat microglia model. Although the isotope labeling scheme for primary microglia is drastically different from that of immortalized cell lines, our de novo and uninterrupted primary culture labeling protocol (DUP-SILAC) resulted in sufficient incorporation of SILAC labels for mass spectrometry-based proteomic profiling. In addition, label incorporation did not alter their morphology and response to endotoxin stimulation. Proteomic analysis of the endotoxin-stimulated SILAC-labeled primary microglia identified expected as well as potentially novel activation markers and pro-inflammatory pathways that could be quantified in a more physiologically relevant cellular model system compared to immortalized cell lines. The establishment of primary microglia SILAC model will further expand our capacity for global scale proteomic profiling of pathways under various physiological and pathological conditions. Proteomic data are available via ProteomeXchange with identifier PXD002759. PMID:26936193

  19. Identification of genes preferentially expressed by microglia and upregulated during cuprizone-induced inflammation.

    PubMed

    Bédard, Andréanne; Tremblay, Pierrot; Chernomoretz, Ariel; Vallières, Luc

    2007-06-01

    Microglia, monocytes, and peripheral macrophages share a common origin and many characteristics, but what distinguishes them from each other at the level of gene expression remains largely unknown. In this study, we compared the transcriptional profiles of freshly purified microglia, monocytes, and spleen macrophages using Affymetrix Mouse Genome arrays to identify genes predominantly expressed by microglia. Among tens of thousands of genes assayed, 127 potential candidates were found, including nine newly discovered genes encoding plasma membrane and extracellular proteins. In the brain, the latter were selectively expressed by microglia, as revealed by in situ hybridization. Three of them were confirmed to be exclusively (MSR2) or predominantly (GPR12, GPR34) expressed in the brain compared to the other tissues examined. Furthermore, all of these genes were upregulated in activated microglia after treatment with the demyelinating toxin cuprizone, suggesting that they play roles in neuroinflammation. In conclusion, this study reports the identification of new selective markers for microglia, which should prove useful not only to identify and isolate these cells, but also to better understand their distinctive properties. PMID:17285589

  20. Microglia in central nervous system repair after injury.

    PubMed

    Jin, Xuemei; Yamashita, Toshihide

    2016-05-01

    Accumulating evidence suggests that immune cells perform crucial inflammation-related functions including clearing dead tissue and promoting wound healing. Thus, they provide a conducive environment for better neuronal regeneration and functional recovery after adult mammalian central nervous system (CNS) injury. However, activated immune cells can also induce secondary damage of intact tissue and inhibit post-injury CNS repair. The inflammation response is due to the microglial production of cytokines and chemokines for the recruitment of peripheral immune cell populations, such as monocytes, neutrophils, dendritic cells and T lymphocytes. Interestingly, microglia and T lymphocytes can be detected at the injured site in both the early and later stages after nerve injury, whereas other peripheral immune cells infiltrate the injured parenchyma of the brain and spinal cord only in the early post-injury phase, and subsequently disappear. This suggests that microglia and T cells may play crucial roles in the post-injury functional recovery of the CNS. In this review, we summarize the current studies on microglia that examined neuronal regeneration and the molecular signalling mechanisms in the injured CNS. Better understanding of the effects of microglia on neural regeneration will aid the development of therapy strategies to enhance CNS functional recovery after injury. PMID:26861995

  1. Supporting Emergent Literacy in Play-based Activities.

    ERIC Educational Resources Information Center

    Hanline, Mary Frances

    2001-01-01

    This article presents ideas for using play activities to support the development of emergent literacy skills in young children, including those with disabilities. Four principles of promoting early literacy skills are explained and applied to activities in block and microsymbolic play, macrosymbolic play, and fluid construction play. The…

  2. Microblogging Activities: Language Play and Tool Transformation

    ERIC Educational Resources Information Center

    Hattem, David

    2014-01-01

    The following is a qualitative case study presenting three vignettes exploring the use of language play while microblogging during an academically sanctioned task. Ten students and one teacher used "Twitter" in an intensive, English as a second language advanced grammar course to practice writing sentences with complex grammatical…

  3. Microglia in Alzheimer's disease: A multifaceted relationship.

    PubMed

    ElAli, Ayman; Rivest, Serge

    2016-07-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting elderly people worldwide, which is mainly characterized by cerebral amyloid-beta (Aβ) plaque deposition and neurofibrillary tangle formation. The interest in microglia arose from the overwhelming experimental evidence that outlined a key role of neuroinflammation in AD pathology. Microglia constitute the powerhouse of the innate immune system in the brain. It is now widely accepted that microglia are myeloid-derived cells that infiltrate the developing brain at the early embryonic stages, and acquire a highly ramified phenotype postnatally. Microglia use these dynamic ramifications as sentinels to sense and detect any occurring alteration in brain homeostasis. Once a danger signal is detected, microglia get activated by acquiring a less ramified phenotype, and mount adequate responses that range from phagocyting cell debris to secreting inflammatory and trophic factors. Earlier reports have demonstrated, unequivocally, that microglia surround Aβ plaques and internalize Aβ microaggregates. However, the implication of these observations in AD pathology, and consequently treatment, is still a matter of debate. Nonetheless, targeting the activity of these cells constituted a convergent point in this debate. Unfortunately, the conflicting experimental findings obtained following the modulation of microglial activity in AD, further fueled the debate. This review aims at providing an overview regarding what we know about the implication of microglia in AD pathology, and treatment. The emerging role of monocytes is also discussed. PMID:26254232

  4. Microglia During Development and Aging

    PubMed Central

    Harry, G. Jean

    2013-01-01

    Microglia are critical nervous system-specific cells influencing brain development, maintenance of the neural environment, response to injury, and repair. They contribute to neuronal proliferation and differentiation, pruning of dying neurons, synaptic remodeling and clearance of debris and aberrant proteins. Colonization of the brain occurs during gestation with an expansion following birth with localization stimulated by programmed neuronal death, synaptic pruning, andaxonal degeneration. Changes inmicroglia phenotype relate to cellular processes including specific neurotransmitter, pattern recognition, or immune-related receptor activation. Upon activation, microglia cells have the capacity to release a number of substances, e.g., cytokines, chemokines, nitric oxide, and reactive oxygen species, which could be detrimental or beneficial to the surrounding cells. With aging, microglia shift their morphology and may display diminished capacity for normal functions related to migration, clearance, and the ability to shift from a pro-inflammatory to an anti-inflammatory state to regulate injury and repair. This shift in microgliapotentially contributes to increased susceptibility and neurodegeneration as a function of age. In the current review, information is provided on the colonization of the brain by microglia, the expression of various pattern recognition receptors to regulate migration and phagocytosis, and the shift in related functions that occur in normal aging. PMID:23644076

  5. Dark microglia: A new phenotype predominantly associated with pathological states

    PubMed Central

    Bisht, Kanchan; Sharma, Kaushik P.; Lecours, Cynthia; Gabriela Sánchez, Maria; El Hajj, Hassan; Milior, Giampaolo; Olmos‐Alonso, Adrián; Gómez‐Nicola, Diego; Luheshi, Giamal; Vallières, Luc; Branchi, Igor; Maggi, Laura; Limatola, Cristina; Butovsky, Oleg

    2016-01-01

    The past decade has witnessed a revolution in our understanding of microglia. These immune cells were shown to actively remodel neuronal circuits, leading to propose new pathogenic mechanisms. To study microglial implication in the loss of synapses, the best pathological correlate of cognitive decline across chronic stress, aging, and diseases, we recently conducted ultrastructural analyses. Our work uncovered the existence of a new microglial phenotype that is rarely present under steady state conditions, in hippocampus, cerebral cortex, amygdala, and hypothalamus, but becomes abundant during chronic stress, aging, fractalkine signaling deficiency (CX3CR1 knockout mice), and Alzheimer's disease pathology (APP‐PS1 mice). Even though these cells display ultrastructural features of microglia, they are strikingly distinct from the other phenotypes described so far at the ultrastructural level. They exhibit several signs of oxidative stress, including a condensed, electron‐dense cytoplasm and nucleoplasm making them as “dark” as mitochondria, accompanied by a pronounced remodeling of their nuclear chromatin. Dark microglia appear to be much more active than the normal microglia, reaching for synaptic clefts, while extensively encircling axon terminals and dendritic spines with their highly ramified and thin processes. They stain for the myeloid cell markers IBA1 and GFP (in CX3CR1‐GFP mice), and strongly express CD11b and microglia‐specific 4D4 in their processes encircling synaptic elements, and TREM2 when they associate with amyloid plaques. Overall, these findings suggest that dark microglia, a new phenotype that we identified based on their unique properties, could play a significant role in the pathological remodeling of neuronal circuits, especially at synapses. GLIA 2016;64:826–839 PMID:26847266

  6. Long-term treadmill exercise improves spatial memory of male APPswe/PS1dE9 mice by regulation of BDNF expression and microglia activation.

    PubMed

    Xiong, J Y; Li, S C; Sun, Y X; Zhang, X S; Dong, Z Z; Zhong, P; Sun, X R

    2015-11-01

    Increasing evidence suggests that physical activity could delay or attenuate the symptoms of Alzheimer's disease (AD). But the underlying mechanisms are still not fully understood. To investigate the effect of long-term treadmill exercise on the spatial memory of AD mice and the possible role of β-amyloid, brain-derived neurotrophic factor (BDNF) and microglia in the effect, male APPswe/PS1dE9 AD mice aged 4 months were subjected to treadmill exercise for 5 months with 6 sessions per week and gradually increased load. A Morris water maze was used to evaluate the spatial memory. Expression levels of β-amyloid, BDNF and Iba-1 (a microglia marker) in brain tissue were detected by immunohistochemistry. Sedentary AD mice and wildtype C57BL/6J mice served as controls. The results showed that 5-month treadmill exercise significantly decreased the escape latencies (P < 0.01 on the 4th day) and improved the spatial memory of the AD mice in the water maze test. Meanwhile, treadmill exercise significantly increased the number of BDNF-positive cells and decreased the ratios of activated microglia in both the cerebral cortex and the hippocampus. However, treadmill exercise did not significantly alleviate the accumulation of β-amyloid in either the cerebral cortex or the hippocampus of the AD mice (P > 0.05). The study suggested that long-term treadmill exercise could improve the spatial memory of the male APPswe/PS1dE9 AD mice. The increase in BDNF-positive cells and decrease in activated microglia might underpin the beneficial effect. PMID:26681831

  7. Long-term treadmill exercise improves spatial memory of male APPswe/PS1dE9 mice by regulation of BDNF expression and microglia activation

    PubMed Central

    Xiong, JY; Li, SC; Sun, YX; Zhang, XS; Dong, ZZ; Zhong, P

    2015-01-01

    Increasing evidence suggests that physical activity could delay or attenuate the symptoms of Alzheimer's disease (AD). But the underlying mechanisms are still not fully understood. To investigate the effect of long-term treadmill exercise on the spatial memory of AD mice and the possible role of β-amyloid, brain-derived neurotrophic factor (BDNF) and microglia in the effect, male APPswe/PS1dE9 AD mice aged 4 months were subjected to treadmill exercise for 5 months with 6 sessions per week and gradually increased load. A Morris water maze was used to evaluate the spatial memory. Expression levels of β-amyloid, BDNF and Iba-1 (a microglia marker) in brain tissue were detected by immunohistochemistry. Sedentary AD mice and wildtype C57BL/6J mice served as controls. The results showed that 5-month treadmill exercise significantly decreased the escape latencies (P < 0.01 on the 4th day) and improved the spatial memory of the AD mice in the water maze test. Meanwhile, treadmill exercise significantly increased the number of BDNF-positive cells and decreased the ratios of activated microglia in both the cerebral cortex and the hippocampus. However, treadmill exercise did not significantly alleviate the accumulation of β-amyloid in either the cerebral cortex or the hippocampus of the AD mice (P > 0.05). The study suggested that long-term treadmill exercise could improve the spatial memory of the male APPswe/PS1dE9 AD mice. The increase in BDNF-positive cells and decrease in activated microglia might underpin the beneficial effect. PMID:26681831

  8. Playing It Smart: Safety in Extracurricular Activities

    ERIC Educational Resources Information Center

    Armenta, Tony

    2011-01-01

    An integral part of the school experience for many students is involvement in extracurricular activities such as athletics, cheerleading, band, and others. Likewise, cocurricular activities, such as field trips, provide a chance for students to connect off-campus experiences to the material learned in the classroom. These types of activities,…

  9. EP4 Receptor-Associated Protein in Microglia Promotes Inflammation in the Brain.

    PubMed

    Fujikawa, Risako; Higuchi, Sei; Nakatsuji, Masato; Yasui, Mika; Ikedo, Taichi; Nagata, Manabu; Yokode, Masayuki; Minami, Manabu

    2016-08-01

    Microglial cells play a key role in neuronal damage in neurodegenerative disorders. Overactivated microglia induce detrimental neurotoxic effects through the excess production of proinflammatory cytokines. However, the mechanisms of microglial activation are poorly understood. We focused on prostaglandin E2 type 4 receptor-associated protein (EPRAP), which suppresses macrophage activation. We demonstrated that EPRAP exists in microglia in the brain. Furthermore, EPRAP-deficient mice displayed less microglial accumulation, and intraperitoneal administration of lipopolysaccharide (LPS) led to reduced expression of tumor necrosis factor-α and monocyte chemoattractant protein-1 mRNA in the brains of EPRAP-deficient mice. Consistently, EPRAP-deficient microglia showed a marked decrease in the production of tumor necrosis factor-α and monocyte chemoattractant protein-1 induced by LPS treatment compared with wild-type controls. In addition, EPRAP deficiency decreased microglial activation and neuronal cell death induced by intraventricular injection of kainic acid. EPRAP deficiency impaired the LPS-induced phosphorylation of c-jun N-terminal kinase and p38 mitogen-activated protein kinase in microglia. The phosphorylation levels of mitogen-activated protein kinase kinase 4-which phosphorylates c-jun N-terminal kinase and p38 mitogen-activated protein kinase-were also decreased in EPRAP-deficient microglia after LPS stimulation. Although EPRAP in macrophages plays a role in the attenuation of inflammation, EPRAP promotes proinflammatory activation of microglia through mitogen-activated protein kinase kinase 4-mediated signaling and may be key to the deteriorating neuronal damage brought on by brain inflammation. PMID:27315781

  10. Changes in Neuronal Excitability by Activated Microglia: Differential Na+ Current Upregulation in Pyramid-Shaped and Bipolar Neurons by TNF-α and IL-18

    PubMed Central

    Klapal, Lars; Igelhorst, Birte A.; Dietzel-Meyer, Irmgard D.

    2016-01-01

    Microglia are activated during pathological events in the brain and are capable of releasing various types of inflammatory cytokines. Here, we demonstrate that the addition of 5% microglia activated by 1 μg/ml lipopolysaccharides (LPS) to hippocampal cultures upregulates Na+ current densities (INavD) of bipolar as well as pyramid-shaped neurons, thereby increasing their excitability. Deactivation of microglia by the addition of 10 ng/ml transforming growth factor-β (TGF-β) decreases INavD below control levels suggesting that the residual activated microglial cells influence neuronal excitability in control cultures. Preincubation of hippocampal cultures with 10 ng/ml tumor necrosis factor-α (TNF-α), a major cytokine released by activated microglia, upregulated INavD significantly by ~30% in bipolar cells, whereas in pyramid-shaped cells, the upregulation only reached an increase of ~14%. Incubation of the cultures with antibodies against either TNF-receptor 1 or 2 blocked the upregulation of INavD in bipolar cells, whereas in pyramid-shaped cells, increases in INavD were exclusively blocked by antibodies against TNF-receptor 2, suggesting that both cell types respond differently to TNF-α exposure. Since additional cytokines, such as interleukin-18 (IL-18), are released from activated microglia, we tested potential effects of IL-18 on INavD in both cell types. Exposure to 5–10 ng/ml IL-18 for 4 days increased INavD in both pyramid-shaped as well as bipolar neurons, albeit the dose–response curves were shifted to lower concentrations in bipolar cells. Our results suggest that by secretion of cytokines, microglial cells upregulate Na+ current densities in bipolar and pyramid-shaped neurons to some extent differentially. Depending on the exact cytokine composition and concentration released, this could change the balance between the activity of inhibitory bipolar and excitatory pyramid-shaped cells. Since bipolar cells show a larger upregulation of

  11. Immunohistochemical characterization of CD33 expression on microglia in Nasu-Hakola disease brains.

    PubMed

    Satoh, Jun-ichi; Kino, Yoshihiro; Motohashi, Nobutaka; Ishida, Tsuyoshi; Yagishita, Saburo; Jinnai, Kenji; Arai, Nobutaka; Nakamagoe, Kiyotaka; Tamaoka, Akira; Saito, Yuko; Arima, Kunimasa

    2015-12-01

    Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder, characterized by formation of multifocal bone cysts and development of leukoencephalopathy, caused by genetic mutations of either DNAX-activation protein 12 (DAP12) or triggering receptor expressed on myeloid cells 2 (TREM2). Although increasing evidence suggests a defect in microglial TREM2/DAP12 function in NHD, the molecular mechanism underlying leukoencephalopathy with relevance to microglial dysfunction remains unknown. TREM2, by transmitting signals via the immunoreceptor tyrosine-based activation motif (ITAM) of DAP12, stimulates phagocytic activity of microglia, and ITAM signaling is counterbalanced by sialic acid-binding immunoglobulin (Ig)-like lectins (Siglecs)-mediated immunoreceptor tyrosine-based inhibitory motif (ITIM) signaling. To investigate a role of CD33, a member of the Siglecs family acting as a negative regulator of microglia activation, in the pathology of NHD, we studied CD33 expression patterns in five NHD brains and 11 controls by immunohistochemistry. In NHD brains, CD33 was identified exclusively on ramified and amoeboid microglia accumulated in demyelinated white matter lesions but not expressed in astrocytes, oligodendrocytes, or neurons. However, the number of CD33-immunoreactive microglia showed great variability from case to case and from lesion to lesion without significant differences between NHD and control brains. These results do not support the view that CD33-expressing microglia play a central role in the development of leukoencephalopathy in NHD brains. PMID:26087043

  12. Host microbiota constantly control maturation and function of microglia in the CNS.

    PubMed

    Erny, Daniel; Hrabě de Angelis, Anna Lena; Jaitin, Diego; Wieghofer, Peter; Staszewski, Ori; David, Eyal; Keren-Shaul, Hadas; Mahlakoiv, Tanel; Jakobshagen, Kristin; Buch, Thorsten; Schwierzeck, Vera; Utermöhlen, Olaf; Chun, Eunyoung; Garrett, Wendy S; McCoy, Kathy D; Diefenbach, Andreas; Staeheli, Peter; Stecher, Bärbel; Amit, Ido; Prinz, Marco

    2015-07-01

    As the tissue macrophages of the CNS, microglia are critically involved in diseases of the CNS. However, it remains unknown what controls their maturation and activation under homeostatic conditions. We observed substantial contributions of the host microbiota to microglia homeostasis, as germ-free (GF) mice displayed global defects in microglia with altered cell proportions and an immature phenotype, leading to impaired innate immune responses. Temporal eradication of host microbiota severely changed microglia properties. Limited microbiota complexity also resulted in defective microglia. In contrast, recolonization with a complex microbiota partially restored microglia features. We determined that short-chain fatty acids (SCFA), microbiota-derived bacterial fermentation products, regulated microglia homeostasis. Accordingly, mice deficient for the SCFA receptor FFAR2 mirrored microglia defects found under GF conditions. These findings suggest that host bacteria vitally regulate microglia maturation and function, whereas microglia impairment can be rectified to some extent by complex microbiota. PMID:26030851

  13. Novel Molecular Insights into Classical and Alternative Activation States of Microglia as Revealed by Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC)-based Proteomics*

    PubMed Central

    Bell-Temin, Harris; Culver-Cochran, Ashley E.; Chaput, Dale; Carlson, Christina M.; Kuehl, Melanie; Burkhardt, Brant R.; Bickford, Paula C.; Liu, Bin; Stevens, Stanley M.

    2015-01-01

    Microglia, the resident immune cells of the brain, have been shown to display a complex spectrum of roles that span from neurotrophic to neurotoxic depending on their activation status. Microglia can be classified into four stages of activation, M1, which most closely matches the classical (pro-inflammatory) activation stage, and the alternative activation stages M2a, M2b, and M2c. The alternative activation stages have not yet been comprehensively analyzed through unbiased, global-scale protein expression profiling. In this study, BV2 mouse immortalized microglial cells were stimulated with agonists specific for each of the four stages and total protein expression for 4644 protein groups was quantified using SILAC-based proteomic analysis. After validating induction of the various stages through a targeted cytokine assay and Western blotting of activation states, the data revealed novel insights into the similarities and differences between the various states. The data identify several protein groups whose expression in the anti-inflammatory, pro-healing activation states are altered presumably to curtail inflammatory activation through differential protein expression, in the M2a state including CD74, LYN, SQST1, TLR2, and CD14. The differential expression of these proteins promotes healing, limits phagocytosis, and limits activation of reactive nitrogen species through toll-like receptor cascades. The M2c state appears to center around the down-regulation of a key member in the formation of actin-rich phagosomes, SLP-76. In addition, the proteomic data identified a novel activation marker, DAB2, which is involved in clathrin-mediated endocytosis and is significantly different between M2a and either M1 or M2b states. Western blot analysis of mouse primary microglia stimulated with the various agonists of the classical and alternative activation states revealed a similar trend of DAB2 expression compared with BV2 cells. PMID:26424600

  14. Novel Molecular Insights into Classical and Alternative Activation States of Microglia as Revealed by Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC)-based Proteomics.

    PubMed

    Bell-Temin, Harris; Culver-Cochran, Ashley E; Chaput, Dale; Carlson, Christina M; Kuehl, Melanie; Burkhardt, Brant R; Bickford, Paula C; Liu, Bin; Stevens, Stanley M

    2015-12-01

    Microglia, the resident immune cells of the brain, have been shown to display a complex spectrum of roles that span from neurotrophic to neurotoxic depending on their activation status. Microglia can be classified into four stages of activation, M1, which most closely matches the classical (pro-inflammatory) activation stage, and the alternative activation stages M2a, M2b, and M2c. The alternative activation stages have not yet been comprehensively analyzed through unbiased, global-scale protein expression profiling. In this study, BV2 mouse immortalized microglial cells were stimulated with agonists specific for each of the four stages and total protein expression for 4644 protein groups was quantified using SILAC-based proteomic analysis. After validating induction of the various stages through a targeted cytokine assay and Western blotting of activation states, the data revealed novel insights into the similarities and differences between the various states. The data identify several protein groups whose expression in the anti-inflammatory, pro-healing activation states are altered presumably to curtail inflammatory activation through differential protein expression, in the M2a state including CD74, LYN, SQST1, TLR2, and CD14. The differential expression of these proteins promotes healing, limits phagocytosis, and limits activation of reactive nitrogen species through toll-like receptor cascades. The M2c state appears to center around the down-regulation of a key member in the formation of actin-rich phagosomes, SLP-76. In addition, the proteomic data identified a novel activation marker, DAB2, which is involved in clathrin-mediated endocytosis and is significantly different between M2a and either M1 or M2b states. Western blot analysis of mouse primary microglia stimulated with the various agonists of the classical and alternative activation states revealed a similar trend of DAB2 expression compared with BV2 cells. PMID:26424600

  15. The suppressive effects of gx-50 on Aβ-induced chemotactic migration of microglia.

    PubMed

    Guo, Yubing; Shi, Shi; Tang, Maoping; Liang, Dongli; Xu, Wangjie; Wang, Lianyun; Wang, Zhaoxia; Qiao, Zhongdong

    2014-04-01

    Microglia, the main immune cells of the central nervous system (CNS), play a vital role in the development of AD. Once microglia are activated, they migrate to neuritic plaques and persistently release pro-inflammatory mediators that lead to neuroinflammation and neuronal degeneration, accelerating the progression of AD. In this study, we analyzed whether an AD candidate drug, N-[2-(3,4-dimethoxyphenyl)ethyl]-3-phenyl-acrylamide (gx-50), a compound extracted from Sichuan pepper (Zanthoxylum bungeanum), exhibited suppressive effects on the chemotactic migration of microglia induced by Aβ. At first, the effects of gx-50 on the migration of primary cultured microglia to Aβ were detected by transwell assay, and the secretion of chemokine CCL5 was measured by ELISA assay. Then, the release of TGF-β1 was detected by ELISA and quantitative real-time PCR, and the activation of the TGF-β1-Smad2 pathway was analyzed by Western blotting. The LDH assay revealed that cell viability was not affected by gx-50 at concentrations from 0.01 to 100 μM; thus, combined with our previous studies, 1 μM was chosen as the treatment concentration. The cell transwell measurement demonstrated that gx-50 suppressed the chemotactic migration of microglia by nearly 50% and inhibited the increase in CCL5 triggered by Aβ. Moreover, the analysis of the TGF-β1-Smad2 pathway revealed that gx-50 can antagonize Aβ-induced down-regulation of TGF-β1 at both the mRNA and protein levels and stimulate the signal pathway activation. Simultaneously, gx-50 pretreatment also significantly enhanced the phosphorylation of glycogen synthase kinase-3β (GSK-3β), which correlated closely with the migration of microglia. In conclusion, in the presence of Aβ, gx-50 pretreatment inhibited the excessive chemotactic migration of microglia. PMID:24508536

  16. β2-adrenergic receptor activation prevents rodent dopaminergic neurotoxicity by inhibiting microglia via a novel signaling pathway

    PubMed Central

    Qian, Li; Wu, Hung-ming; Chen, Shih-Heng; Zhang, Dan; Ali, Syed F.; Peterson, Lynda; Wilson, Belinda; Lu, Ru-Band; Hong, Jau-Shyong; Flood, Patrick M

    2013-01-01

    The role of the β2 Adrenergic Receptor (β2AR) in the regulation of chronic neurodegenerative inflammation within the CNS is poorly understood. The purpose of this study was to determine neuroprotective effects of long-acting β2AR agonists such as salmeterol in rodent models of Parkinson’s disease. Results showed salmeterol exerted potent neuroprotection against both LPS and MPTP/MPP+-induced dopaminergic neurotoxicity both in primary neuron-glia cultures (at sub-nanomolar concentrations) and in mice (1–10 μg/kg/day doses). Further studies demonstrated that salmeterol-mediated neuroprotection is not a direct effect on neurons; instead, it is mediated through the inhibition of LPS-induced microglial activation. Salmeterol significantly inhibited LPS-induced production of microglial pro-inflammatory neurotoxic mediators, such as TNFα, superoxide and nitric oxide, as well as the inhibition of TAK1-mediated phosphorylation of MAPK and p65 NF-κB. The anti-inflammatory effects of salmeterol required β2AR expression in microglia, but were not mediated through the conventional GPCR/cAMP pathway. Rather, salmeterol failed to induce microglial cAMP production, could not be reversed by either PKA inhibitors or an EPAC agonist, and was dependent on beta-arrestin2 expression. Together, our results demonstrate that administration of extremely low doses of salmeterol exhibit potent neuroprotective effects by inhibiting microglial cell activation through a β2AR/β-arrestin2-dependent but cAMP/PKA independent pathway. PMID:21335487

  17. Transition Problems and Play as Transitory Activity

    ERIC Educational Resources Information Center

    Brostrom, Stig

    2005-01-01

    Because too many children experience the transition to school as a culture shock, during the past decade teachers have implemented so-called transition activities in order to bridge the gap between preschool and school. However, transition to school also calls for a development of higher mental functions, among others the development of children's…

  18. Pay for Play: Fees for Cocurricular Activities.

    ERIC Educational Resources Information Center

    Pepe, Thomas J.; Tufts, Alice L.

    1984-01-01

    As school budgets face serious problems, one area under examination is the cocurricular activities section of the school budget. Many districts are charging user fees to students participating in school sports, band, drama, and even elective courses. Since no direct reference is made to education in the United States Constitution, education is a…

  19. Activation of corticotropin-releasing factor neurons and microglia in paraventricular nucleus precipitates visceral hypersensitivity induced by colorectal distension in rats.

    PubMed

    Zhang, Gongliang; Yu, Le; Chen, Zi-Yang; Zhu, Jun-Sheng; Hua, Rong; Qin, Xia; Cao, Jun-Li; Zhang, Yong-Mei

    2016-07-01

    Visceral hypersensitivity is a major contributor to irritable bowel syndrome and other disorders with visceral pain. Substantial evidence has established that glial activation and neuro-glial interaction play a key role in the establishment and maintenance of visceral hypersensitivity. We recently demonstrated that activation of spinal microglial toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor κB (NF-κB) signaling facilitated the development of visceral hypersensitivity in a rat model developed by neonatal and adult colorectal distensions (CRDs). Hypothalamic paraventricular nucleus (PVN) plays a pivotal role in the pathogenesis of chronic pain. In this study, we examined the mechanism by which microglia and neurons in PVN establish and maintain visceral hypersensitivity and the involvement of TLR4 signaling. Visceral hypersensitivity was precipitated by adult colorectal distension (CRD) only in rats that experienced neonatal CRDs. Visceral hypersensitivity was associated with an increase in the expression of c-fos, corticotropin-releasing factor (CRF) protein and mRNA in PVN, which could be prevented by intra-PVN infusion of lidocaine or small interfering RNA targeting the CRF gene. These results suggest PVN CRF neurons modulate visceral hypersensitivity. Adult CRD induced an increase in the expression of Iba-1 (a microglial marker), TLR4 protein, and its downstream effectors MyD88, NF-κB, as well as proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) only in rats that experienced neonatal CRDs. Intra-PVN infusion of minocycline, a nonselective microglial inhibitor, attenuated the hyperactivity of TLR4 signaling cascade, microglial activation, and visceral hypersensitivity. Taken together, these data suggest that neonatal CRDs induce a glial activation in PVN. Adult CRD potentiates the glial and CRF neuronal activity, and precipitates visceral hypersensitivity and pain. TLR4 signaling and

  20. Play

    NASA Astrophysics Data System (ADS)

    Harteveld, Casper

    Designing a game with a serious purpose involves considering the worlds of Reality and Meaning yet it is undeniably impossible to create a game without a third world, one that is specifically concerned with what makes a game a game: the play elements. This third world, the world of people like designers and artists, and disciplines as computer science and game design, I call the world of Play and this level is devoted to it. The level starts off with some of the misperceptions people have of play. Unlike some may think, we play all the time, even when we grow old—this was also very noticeable in designing the game Levee Patroller as the team exhibited very playful behavior at many occasions. From there, I go into the aspects that characterize this world. The first concerns the goal of the game. This relates to the objectives people have to achieve within the game. This is constituted by the second aspect: the gameplay. Taking actions and facing challenges is subsequently constituted by a gameworld, which concerns the third aspect. And all of it is not possible without the fourth and final aspect, the type of technology that creates and facilitates the game. The four aspects together make up a “game concept” and from this world such a concept can be judged on the basis of three closely interrelated criteria: engagement, immersion, and fun.

  1. Microglia-Induced Maladaptive Plasticity Can Be Modulated by Neuropeptides In Vivo

    PubMed Central

    Morara, Stefano; Colangelo, Anna Maria; Provini, Luciano

    2015-01-01

    Microglia-induced maladaptive plasticity is being recognized as a major cause of deleterious self-sustaining pathological processes that occur in neurodegenerative and neuroinflammatory diseases. Microglia, the primary homeostatic guardian of the central nervous system, exert critical functions both during development, in neural circuit reshaping, and during adult life, in the brain physiological and pathological surveillance. This delicate critical role can be disrupted by neural, but also peripheral, noxious stimuli that can prime microglia to become overreactive to a second noxious stimulus or worsen underlying pathological processes. Among regulators of microglia, neuropeptides can play a major role. Their receptors are widely expressed in microglial cells and neuropeptide challenge can potently influence microglial activity in vitro. More relevantly, this regulator activity has been assessed also in vivo, in experimental models of brain diseases. Neuropeptide action in the central nervous system has been associated with beneficial effects in neurodegenerative and neuroinflammatory pathological experimental models. This review describes some of the mechanisms of the microglia maladaptive plasticity in vivo and how neuropeptide activity can represent a useful therapeutical target in a variety of human brain pathologies. PMID:26273481

  2. Resveratrol induces the expression of interleukin-10 and brain-derived neurotrophic factor in BV2 microglia under hypoxia.

    PubMed

    Song, Juhyun; Cheon, So Yeong; Jung, Wonsug; Lee, Won Taek; Lee, Jong Eun

    2014-01-01

    Microglia are the resident macrophages of the central nervous system (CNS) and play an important role in neuronal recovery by scavenging damaged neurons. However, overactivation of microglia leads to neuronal death that is associated with CNS disorders. Therefore, regulation of microglial activation has been suggested to be an important target for treatment of CNS diseases. In the present study, we investigated the beneficial effect of resveratrol, a natural phenol with antioxidant effects, in the microglial cell line, BV2, in a model of hypoxia injury. Resveratrol suppressed the mRNA expression of the pro-inflammatory molecule, tumor necrosis factor-α, and promoted the mRNA expression of the anti-inflammatory molecule, interleukin-10, in BV2 microglia under hypoxic conditions. In addition, resveratrol inhibited the activation of the transcription factor, nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), which is upstream in the control of inflammatory reactions in hypoxia-injured BV2 microglia. Moreover, resveratrol promoted the expression of brain-derived neurotrophic factor (BDNF) in BV2 microglia under hypoxic stress. Overall, resveratrol may promote the beneficial function of microglia in ischemic brain injury. PMID:25184950

  3. Microglia are crucial regulators of neuro-immunity during central nervous system tuberculosis

    PubMed Central

    Spanos, Jonathan Paul; Hsu, Nai-Jen; Jacobs, Muazzam

    2015-01-01

    Mycobacterium tuberculosis (M. tuberculosis) infection of the central nervous system (CNS) is the most devastating manifestation of tuberculosis (TB), with both high mortality and morbidity. Although research has been fueled by the potential therapeutic target microglia offer against neurodegenerative inflammation, their part in TB infection of the CNS has not been fully evaluated nor elucidated. Yet, as both the preferential targets of M. tuberculosis and the immune-effector cells of the CNS, microglia are likely to be key determinants of disease severity and clinical outcomes. Following pathogen recognition, bacilli are internalized and capable of replicating within microglia. Cellular activation ensues, utilizing signaling molecules that may be neurotoxic. Central to initiating, orchestrating and modulating the tuberculous immune response is microglial secretion of cytokines and chemokines. However, the neurological environment is unique in that inflammatory signals, which appear to be damaging in the periphery, could be beneficial by governing neuronal survival, regeneration and differentiation. Furthermore, microglia are important in the recruitment of peripheral immune cells and central to defining the pro-inflammatory milieu of which neurotoxicity may result from many of the participating local or recruited cell types. Microglia are capable of both presenting antigen to infiltrating CD4+ T-lymphocytes and inducing their differentiation—a possible correlate of protection against M. tuberculosis infection. Clarifying the nature of the immune effector molecules secreted by microglia, and the means by which other CNS-specific cell types govern microglial activation or modulate their responses is critical if improved diagnostic and therapeutic strategies are to be attained. Therefore, this review evaluates the diverse roles microglia play in the neuro-immunity to M. tuberculosis infection of the CNS. PMID:26041993

  4. Microglia Activated with the Toll-Like Receptor 9 Ligand CpG Attenuate Oligomeric Amyloid β Neurotoxicity in in Vitro and in Vivo Models of Alzheimer’s Disease

    PubMed Central

    Doi, Yukiko; Mizuno, Tetsuya; Maki, Yuki; Jin, Shijie; Mizoguchi, Hiroyuki; Ikeyama, Masayoshi; Doi, Minoru; Michikawa, Makoto; Takeuchi, Hideyuki; Suzumura, Akio

    2009-01-01

    Soluble oligomeric amyloid β (oAβ) 1-42 causes synaptic dysfunction and neuronal injury in Alzheimer’s disease (AD). Although accumulation of microglia around senile plaques is a hallmark of AD pathology, the role of microglia in oAβ1-42 neurotoxicity is not fully understood. Here, we showed that oAβ but not fibrillar Aβ was neurotoxic, and microglia activated with unmethylated DNA CpG motif (CpG), a ligand for Toll-like receptor 9, attenuated oAβ1-42 neurotoxicity in primary neuron-microglia co-cultures. CpG enhanced microglial clearance of oAβ1-42 and induced higher levels of the antioxidant enzyme heme oxygenase-1 in microglia without producing neurotoxic molecules such as nitric oxide and glutamate. Among subclasses of CpGs, class B and class C activated microglia to promote neuroprotection. Moreover, intracerebroventricular administration of CpG ameliorated both the cognitive impairments induced by oAβ1-42 and the impairment of associative learning in Tg2576 mouse model of AD. We propose that CpG may be an effective therapeutic strategy for limiting oAβ1-42 neurotoxicity in AD. PMID:19834064

  5. Maternal inflammation leads to impaired glutamate homeostasis and up-regulation of glutamate carboxypeptidase II in activated microglia in the fetal/newborn rabbit brain.

    PubMed

    Zhang, Zhi; Bassam, Bassam; Thomas, Ajit G; Williams, Monica; Liu, Jinhuan; Nance, Elizabeth; Rojas, Camilo; Slusher, Barbara S; Kannan, Sujatha

    2016-10-01

    Astrocyte dysfunction and excessive activation of glutamatergic systems have been implicated in a number of neurologic disorders, including periventricular leukomalacia (PVL) and cerebral palsy (CP). However, the role of chorioamnionitis on glutamate homeostasis in the fetal and neonatal brains is not clearly understood. We have previously shown that intrauterine endotoxin administration results in intense microglial 'activation' and increased pro-inflammatory cytokines in the periventricular region (PVR) of the neonatal rabbit brain. In this study, we assessed the effect of maternal inflammation on key components of the glutamate pathway and its relationship to astrocyte and microglial activation in the fetal and neonatal New Zealand white rabbit brain. We found that intrauterine endotoxin exposure at gestational day 28 (G28) induced acute and prolonged glutamate elevation in the PVR of fetal (G29, 1day post-injury) and postnatal day 1 (PND1, 3days post-injury) brains along with prominent morphological changes in the astrocytes (soma hypertrophy and retracted processes) in the white matter tracts. There was a significant increase in glutaminase and N-Methyl-d-Aspartate receptor (NMDAR) NR2 subunit expression along with decreased glial L-glutamate transporter 1 (GLT-1) in the PVR at G29, that would promote acute dysregulation of glutamate homeostasis. This was accompanied with significantly decreased TGF-β1 at PND1 in CP kits indicating ongoing neuroinflammation. We also show for the first time that glutamate carboxypeptidase II (GCPII) was significantly increased in the activated microglia at the periventricular white matter area in both G29 and PND1 CP kits. This was confirmed by in vitro studies demonstrating that LPS activated primary microglia markedly upregulate GCPII enzymatic activity. These results suggest that maternal intrauterine endotoxin exposure results in early onset and long-lasting dysregulation of glutamate homeostasis, which may be mediated by

  6. Curcumin suppresses Janus kinase-STAT inflammatory signaling through activation of Src homology 2 domain-containing tyrosine phosphatase 2 in brain microglia.

    PubMed

    Kim, Hee Young; Park, Eun Jung; Joe, Eun-Hye; Jou, Ilo

    2003-12-01

    Curcumin has been strongly implicated as an anti-inflammatory agent, but the precise mechanisms of its action are largely unknown. In this study, we show that the inhibitory action of curcumin on Janus kinase (JAK)-STAT signaling can contribute to its anti-inflammatory activity in the brain. In both rat primary microglia and murine BV2 microglial cells, curcumin effectively suppressed the ganglioside-, LPS-, or IFN-gamma-stimulated induction of cyclooxygenase-2 and inducible NO synthase, important enzymes that mediate inflammatory processes. These anti-inflammatory effects appear to be due, at least in part, to the suppression of the JAK-STAT inflammatory signaling cascade. Curcumin markedly inhibited the phosphorylation of STAT1 and 3 as well as JAK1 and 2 in microglia activated with gangliosides, LPS, or IFN-gamma. Curcumin consistently suppressed not only NF binding to IFN-gamma-activated sequence/IFN-stimulated regulatory element, but also the expression of inflammation-associated genes, including ICAM-1 and monocyte chemoattractant protein 1, whose promoters contain STAT-binding elements. We further show that activation of Src homology 2 domain-containing protein tyrosine phosphatases (SHP)-2, a negative regulator of JAK activity, is likely to be one of the mechanisms underlying the curcumin-mediated inhibition of JAK-STAT signaling. Treatment of microglial cells with curcumin led to an increase in phosphorylation and association with JAK1/2 of SHP-2, which inhibit the initiation of JAK-STAT inflammatory signaling in activated microglia. Taken together, these data suggest curcumin suppresses JAK-STAT signaling via activation of SHP-2, thus attenuating inflammatory response of brain microglial cells. PMID:14634121

  7. Antibody-mediated inhibition of integrin α5β1 blocks neurotoxic prion peptide PrP106-126-induced activation of BV2 microglia.

    PubMed

    Chang, Jiaxin; Yang, Lifeng; Kouadir, Mohammed; Peng, Yun; Zhang, Siming; Shi, Fushan; Zhou, Xiangmei; Yin, Xiaomin; Zhao, Deming

    2012-09-01

    Microglial activation is a characteristic feature of the pathogenesis of prion diseases. The identification of cell surface molecules that mediate the prion protein (PrP) synthetic peptide interaction with microglia is of great significance as it represents potential target molecules to modulate the events leading to the pathophysiology of prion diseases. Here, we carried out in vitro experiments to investigate the involvement of α5β1 integrin in neurotoxic prion peptide PrP(106-126)-induced activation of BV2 microglia. The results showed that the exposure to PrP(106-126) upregulated the mRNA expression of proinflammatory factors (IL-1 β, IL-6, and iNOS) and NALP3 inflammasome components (NALP3 and ASC), increased the release of iNOS and its product nitric oxide, and stimulated NF-κB activation. Blockade of α5β1 integrin with monoclonal antibody BMC5 prior to PrP(106-126) treatment abrogated the upregulation of the mRNA expression of IL-1 β, IL-6, iNOS, and ASC, but had no effect on the mRNA expression of NALP3, blocked the release of iNOS and nitric oxide, and inhibited NF-κB activation. These results suggest that α5β1 integrin is involved in the PrP(106-126)-induced microglial activation through the participation in the activation of NF-κB and NALP3/ASC inflammasome. Our study unveils a previously unidentified role of α5β1 integrin as an intermediate signaling molecule in neurotoxic prion peptides-microglia interactions and identifies a potential molecular target for the modulation of prion-induced microglial activation. PMID:22648512

  8. Actin dynamics shape microglia effector functions.

    PubMed

    Uhlemann, Ria; Gertz, Karen; Boehmerle, Wolfgang; Schwarz, Tobias; Nolte, Christiane; Freyer, Dorette; Kettenmann, Helmut; Endres, Matthias; Kronenberg, Golo

    2016-06-01

    Impaired actin filament dynamics have been associated with cellular senescence. Microglia, the resident immune cells of the brain, are emerging as a central pathophysiological player in neurodegeneration. Microglia activation, which ranges on a continuum between classical and alternative, may be of critical importance to brain disease. Using genetic and pharmacological manipulations, we studied the effects of alterations in actin dynamics on microglia effector functions. Disruption of actin dynamics did not affect transcription of genes involved in the LPS-triggered classical inflammatory response. By contrast, in consequence of impaired nuclear translocation of phospho-STAT6, genes involved in IL-4 induced alternative activation were strongly downregulated. Functionally, impaired actin dynamics resulted in reduced NO secretion and reduced release of TNFalpha and IL-6 from LPS-stimulated microglia and of IGF-1 from IL-4 stimulated microglia. However, pathological stabilization of the actin cytoskeleton increased LPS-induced release of IL-1beta and IL-18, which belong to an unconventional secretory pathway. Reduced NO release was associated with decreased cytoplasmic iNOS protein expression and decreased intracellular arginine uptake. Furthermore, disruption of actin dynamics resulted in reduced microglia migration, proliferation and phagocytosis. Finally, baseline and ATP-induced [Ca(2+)]int levels were significantly increased in microglia lacking gelsolin, a key actin-severing protein. Together, the dynamic state of the actin cytoskeleton profoundly and distinctly affects microglia behaviours. Disruption of actin dynamics attenuates M2 polarization by inhibiting transcription of alternative activation genes. In classical activation, the role of actin remodelling is complex, does not relate to gene transcription and shows a major divergence between cytokines following conventional and unconventional secretion. PMID:25989853

  9. Centrally Delivered BACE1 Inhibitor Activates Microglia, and Reverses Amyloid Pathology and Cognitive Deficit in Aged Tg2576 Mice.

    PubMed

    Thakker, Deepak R; Sankaranarayanan, Sethu; Weatherspoon, Marcy R; Harrison, Jonathan; Pierdomenico, Maria; Heisel, Jennifer M; Thompson, Lorin A; Haskell, Roy; Grace, James E; Taylor, Sarah J; Albright, Charles F; Shafer, Lisa L

    2015-04-29

    Multiple small-molecule inhibitors of the β-secretase enzyme (BACE1) are under preclinical or clinical investigation for Alzheimer's disease (AD). Prior work has illustrated robust lowering of central amyloid β (Aβ) after acute administration of BACE1 inhibitors. However, very few studies have assessed the overall impact of chronically administered BACE1 inhibitors on brain amyloid burden, neuropathology, and behavioral function in aged preclinical models. We investigated the effects of a potent nonbrain-penetrant BACE1 inhibitor, delivered directly to the brain using intracerebroventricular infusion in an aged transgenic mouse model. Intracerebroventricular infusion of the BACE1 inhibitor (0.3-23.5 μg/d) for 8 weeks, initiated in 17-month-old Tg2576 mice, produced dose-dependent increases in brain inhibitor concentrations (0.2-13 μm). BACE1 inhibition significantly reversed the behavioral deficit in contextual fear conditioning, and reduced brain Aβ levels, plaque burden, and associated pathology (e.g., dystrophic neurites), with maximal effects attained with ∼1 μg/d dose. Strikingly, the BACE1 inhibitor also reversed amyloid pathology below baseline levels (amyloid burden at the start of treatment), without adversely affecting cerebral amyloid angiopathy, microhemorrhages, myelination, or neuromuscular function. Inhibitor-mediated decline in brain amyloid pathology was associated with an increase in microglial ramification. This is the first demonstration of chronically administered BACE1 inhibitor to activate microglia, reverse brain amyloid pathology, and elicit functional improvement in an aged transgenic mouse model. Thus, engagement of novel glial-mediated clearance mechanisms may drive disease-modifying therapeutic benefit with BACE1 inhibition in AD. PMID:25926467

  10. Small molecule glutaminase inhibitors block glutamate release from stimulated microglia.

    PubMed

    Thomas, Ajit G; O'Driscoll, Cliona M; Bressler, Joseph; Kaufmann, Walter; Rojas, Camilo J; Slusher, Barbara S

    2014-01-01

    Glutaminase plays a critical role in the generation of glutamate, a key excitatory neurotransmitter in the CNS. Excess glutamate release from activated macrophages and microglia correlates with upregulated glutaminase suggesting a pathogenic role for glutaminase. Both glutaminase siRNA and small molecule inhibitors have been shown to decrease excess glutamate and provide neuroprotection in multiple models of disease, including HIV-associated dementia (HAD), multiple sclerosis and ischemia. Consequently, inhibition of glutaminase could be of interest for treatment of these diseases. Bis-2-(5-phenylacetimido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES) and 6-diazo-5-oxo-l-norleucine (DON), two most commonly used glutaminase inhibitors, are either poorly soluble or non-specific. Recently, several new BPTES analogs with improved physicochemical properties were reported. To evaluate these new inhibitors, we established a cell-based microglial activation assay measuring glutamate release. Microglia-mediated glutamate levels were significantly augmented by tumor necrosis factor (TNF)-α, phorbol 12-myristate 13-acetate (PMA) and Toll-like receptor (TLR) ligands coincident with increased glutaminase activity. While several potent glutaminase inhibitors abrogated the increase in glutamate, a structurally related analog devoid of glutaminase activity was unable to block the increase. In the absence of glutamine, glutamate levels were significantly attenuated. These data suggest that the in vitro microglia assay may be a useful tool in developing glutaminase inhibitors of therapeutic interest. PMID:24269238

  11. The Need for Play & Play-Like Activities in the Junior Classroom.

    ERIC Educational Resources Information Center

    Silver, Allan

    1992-01-01

    Draws from personal experiences in teaching a fourth-grade class in Canada to highlight the benefits for students of incorporating into the curriculum such playlike activities as shaping plasticine models, painting, cutting and pasting, and playing games. Identifies skills reinforced by particular activities and the benefits of the activities to…

  12. Microglia and the urokinase plasminogen activator receptor/uPA system in innate brain inflammation.

    PubMed

    Cunningham, Orla; Campion, Suzanne; Perry, V Hugh; Murray, Carol; Sidenius, Nicolai; Docagne, Fabian; Cunningham, Colm

    2009-12-01

    The urokinase plasminogen activator (uPA) receptor (uPAR) is a GPI-linked cell surface protein that facilitates focused plasmin proteolytic activity at the cell surface. uPAR has been detected in macrophages infiltrating the central nervous system (CNS) and soluble uPAR has been detected in the cerebrospinal fluid during a number of CNS pathologies. However, its expression by resident microglial cells in vivo remains uncertain. In this work, we aimed to elucidate the murine CNS expression of uPAR and uPA as well as that of tissue plasminogen activator and plasminogen activator inhibitor 1 (PAI-1) during insults generating distinct and well-characterized inflammatory responses; acute intracerebral lipopolysaccharide (LPS), acute kainate-induced neurodegeneration, and chronic neurodegeneration induced by prion disease inoculation. All three insults induced marked expression of uPAR at both mRNA and protein level compared to controls (naïve, saline, or control inoculum-injected). uPAR expression was microglial in all cases. Conversely, uPA transcription and activity was only markedly increased during chronic neurodegeneration. Dissociation of uPA and uPAR levels in acute challenges is suggestive of additional proteolysis-independent roles for uPAR. PAI-1 was most highly expressed upon LPS challenge, whereas tissue plasminogen activator mRNA was constitutively present and less responsive to all insults studied. These data are novel and suggest much wider involvement of the uPAR/uPA system in CNS function and pathology than previously supposed. PMID:19459212

  13. Activation of microglia with zymosan promotes excitatory amino acid release via volume-regulated anion channels: the role of NADPH oxidases

    PubMed Central

    Harrigan, Timothy J.; Abdullaev, Iskandar F.; Jourd'heuil, David; Mongin, Alexander A.

    2008-01-01

    Microglia are the resident immune cells of the CNS, which are important for preserving neural tissue functions, but may also contribute to neurodegeneration. Activation of these cells in infection, inflammation, or trauma leads to the release of various toxic molecules, including reactive oxygen species (ROS) and the excitatory amino acid glutamate. In this study we used an electrophysiological approach and a D-[3H]aspartate (glutamate) release assay to explore the ROS-dependent regulation of glutamate-permeable volume-regulated anion channels (VRACs). Exposure of rat microglia to hypoosmotic media stimulated Cl− currents and D-[3H]aspartate release, both of which were inhibited by the selective VRAC blocker DCPIB. Exogenously applied H2O2 potently increased swelling-activated glutamate release. Stimulation of microglia with zymosan triggered production of endogenous ROS and strongly enhanced glutamate release via VRAC in swollen cells. The effects of zymosan were attenuated by the ROS scavenger MnTMPyP, and by two inhibitors of NADPH oxidase (NOX) diphenyliodonium and thioridazine. However, zymosan-stimulated glutamate release was insensitive to other NOX blockers, apocynin and AEBSF. This pharmacological profile pointed to the potential involvement of apocynin-insensitive NOX4. Using RT-PCR we confirmed that NOX4 is expressed in rat microglial cells, along with NOX1 and NOX2. To check for potential involvement of phagocytic NOX2 we stimulated this isoform using protein kinase C (PKC) activator PMA, or inhibited it with the broad spectrum PKC blocker Gö6983. Both agents potently modulated endogenous ROS production by NOX2, but not VRAC activity. Taken together, these data suggest that the anion channel VRAC may contribute to microglial glutamate release, and that its activity is regulated by endogenous ROS originating from NOX4. PMID:18624925

  14. Repurposing psychiatric medicines to target activated microglia in anxious mild cognitive impairment and early Parkinson's disease.

    PubMed

    Lauterbach, Edward C

    2016-01-01

    Anxiety is common in the Mild Cognitive Impairment (MCI) stage of Alzheimer's disease (AD) and the pre-motor stages of Parkinson's disease (PD). A concomitant and possible cause of this anxiety is microglial activation, also considered a key promoter of neurodegeneration in MCI and early PD via inflammatory mechanisms and the generation of degenerative proinflammatory cytokines. Psychiatric disorders, prevalent in AD and PD, are often treated with psychiatric drugs (psychotropics), raising the question of whether psychotropics might therapeutically affect microglial activation, MCI, and PD. The literature of common psychotropics used in treating psychiatric disorders was reviewed for preclinical and clinical findings regarding microglial activation. Findings potentially compatible with reduced microglial activation or reduced microglial inflammogen release were evident for: antipsychotics including neuroleptics (chlorpromazine, thioridazine, loxapine) and atypicals (aripiprazole, olanzapine, quetiapine, risperidone, ziprasidone); mood stabilizers (carbamazepine, valproate, lithium); antidepressants including tricyclics (amitriptyline, clomipramine, imipramine, nortriptyline), SSRIs (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline), venlafaxine, and bupropion; benzodiazepine anxiolytics (clonazepam, diazepam); cognitive enhancers (donepezil, galantamine, memantine); and other drugs (dextromethorphan, quinidine, amantadine). In contrast, pramipexole and methylphenidate might promote microglial activation. The most promising replicated findings of reduced microglial activation are for quetiapine, valproate, lithium, fluoxetine, donepezil, and memantine but further study is needed and translation of their microglial effects to human disease still requires investigation. In AD-relevant models, risperidone, valproate, lithium, fluoxetine, bupropion, donepezil, and memantine have therapeutic microglial effects in need of replication. Limited

  15. Defining the Microglia Response during the Time Course of Chronic Neurodegeneration

    PubMed Central

    Vincenti, James E.; Murphy, Lita; Grabert, Kathleen; McColl, Barry W.; Cancellotti, Enrico; Freeman, Tom C.

    2015-01-01

    ABSTRACT Inflammation has been proposed as a major component of neurodegenerative diseases, although the precise role it plays has yet to be defined. We examined the role of key contributors to this inflammatory process, microglia, the major resident immune cell population of the brain, in a prion disease model of chronic neurodegeneration. Initially, we performed an extensive reanalysis of a large study of prion disease, where the transcriptome of mouse brains had been monitored throughout the time course of disease. Our analysis has provided a detailed classification of the disease-associated genes based on cell type of origin and gene function. This revealed that the genes upregulated during disease, regardless of the strain of mouse or prion protein, are expressed predominantly by activated microglia. In order to study the microglia contribution more specifically, we established a mouse model of prion disease in which the 79A murine prion strain was introduced by an intraperitoneal route into BALB/cJFms-EGFP/− mice, which express enhanced green fluorescent protein under the control of the c-fms operon. Samples were taken at time points during disease progression, and histological analysis of the brain and transcriptional analysis of isolated microglia was carried out. The analysis of isolated microglia revealed a disease-specific, highly proinflammatory signature in addition to an upregulation of genes associated with metabolism and respiratory stress. This study strongly supports the growing recognition of the importance of microglia within the prion disease process and identifies the nature of the response through gene expression analysis of isolated microglia. IMPORTANCE Inflammation has been proposed as a major component of neurodegenerative diseases. We have examined the role of key contributors to this inflammatory process, microglia, the major resident immune cell population of the brain, in a murine prion disease model of chronic neurodegeneration

  16. A Comparative Study of Active Play on Differently Designed Playgrounds

    ERIC Educational Resources Information Center

    Luchs, Antje; Fikus, Monika

    2013-01-01

    The physical and social environment of children in cities is continuously changing. Knowledge about the positive effects of natural play experiences within the child's development is becoming widely known. Affordances of diverse landscape elements and especially loose parts for play in natural environments influence play activities. New…

  17. Nutritional and Nanotechnological Modulators of Microglia

    PubMed Central

    Maysinger, Dusica; Zhang, Issan

    2016-01-01

    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. PMID:27471505

  18. Nutritional and Nanotechnological Modulators of Microglia.

    PubMed

    Maysinger, Dusica; Zhang, Issan

    2016-01-01

    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. PMID:27471505

  19. The azetidine derivative, KHG26792 protects against ATP-induced activation of NFAT and MAPK pathways through P2X7 receptor in microglia.

    PubMed

    Kim, Eun-A; Cho, Chang Hun; Kim, Jiae; Hahn, Hoh-Gyu; Choi, Soo Young; Yang, Seung-Ju; Cho, Sung-Woo

    2015-12-01

    Azetidine derivatives are of interest for drug development because they may be useful therapeutic agents. However, their mechanisms of action remain to be completely elucidated. Here, we have investigated the effects of 3-(naphthalen-2-yl(propoxy)methyl)azetidine hydrochloride (KHG26792) on ATP-induced activation of NFAT and MAPK through P2X7 receptor in the BV-2 mouse microglial cell line. KHG26792 decreased ATP-induced TNF-α release from BV-2 microglia by suppressing, at least partly, P2X7 receptor stimulation. KHG26792 also inhibited the ATP-induced increase in IL-6, PGE2, NO, ROS, CXCL2, and CCL3. ATP induced NFAT activation through P2X7 receptor, with KHG26792 reducing the ATP-induced NFAT activation. KHG26792 inhibited an ATP-induced increase in iNOS protein and ERK phosphorylation. KHG26792 prevented an ATP-induced increase in MMP-9 activity through the P2X7 receptor as a result of degradation of TIMP-1 by cathepsin B. Our data provide mechanistic insights into the role of KHG26792 in the inhibition of TNF-α produced via P2X7 receptor-mediated activation of NFAT and MAPK pathways in ATP-treated BV-2 cells. This study highlights the potential use of KHG26792 as a therapeutic agent for the many diseases of the CNS related to activated microglia. PMID:26522449

  20. Induction of microglia activation after infection with the non-neurotropic A/CA/04/2009 H1N1 influenza virus.

    PubMed

    Sadasivan, Shankar; Zanin, Mark; O'Brien, Kevin; Schultz-Cherry, Stacey; Smeyne, Richard J

    2015-01-01

    Although influenza is primarily a respiratory disease, it has been shown, in some cases, to induce encephalitis, including people acutely infected with the pandemic A/California/04/2009 (CA/09) H1N1 virus. Based on previous studies showing that the highly pathogenic avian influenza (HPAI) A/Vietnam/1203/2004 H5N1 virus was neurotropic, induced CNS inflammation and a transient parkinsonism, we examined the neurotropic and inflammatory potential of the CA/09 H1N1 virus in mice. Following intranasal inoculation, we found no evidence for CA/09 H1N1 virus neurotropism in the enteric, peripheral or central nervous systems. We did, however, observe a robust increase in microglial activity in the brain characterized by an increase in the number of activated Iba-1-positive microglia in the substantia nigra (SN) and the hippocampus, despite the absence of virus in the brain. qPCR analysis in SN tissue showed that the induction of microgliosis was preceded by reduced gene expression of the neurotrophic factors bdnf, and gdnf and increases in the immune modulatory chemokine chemokine (C-C motif) ligand 4 (ccl4). We also noted changes in the expression of transforming growth factor-1 (tgfβ1) in the SN starting at 7 days post-infection (dpi) that was sustained through 21 dpi, coupled with increases in arginase-1 (arg1) and csf1, M2 markers for microglia. Given that neuroinflammation contributes to generation and progression of a number of neurodegenerative disorders, these findings have significant implications as they highlight the possibility that influenza and perhaps other non-neurotropic viruses can initiate inflammatory signals via microglia activation in the brain and contribute to, but not necessarily be the primary cause of, neurodegenerative disorders. PMID:25861024

  1. SEMA4D compromises blood-brain barrier, activates microglia, and inhibits remyelination in neurodegenerative disease.

    PubMed

    Smith, Ernest S; Jonason, Alan; Reilly, Christine; Veeraraghavan, Janaki; Fisher, Terrence; Doherty, Michael; Klimatcheva, Ekaterina; Mallow, Crystal; Cornelius, Chad; Leonard, John E; Marchi, Nicola; Janigro, Damir; Argaw, Azeb Tadesse; Pham, Trinh; Seils, Jennifer; Bussler, Holm; Torno, Sebold; Kirk, Renee; Howell, Alan; Evans, Elizabeth E; Paris, Mark; Bowers, William J; John, Gareth; Zauderer, Maurice

    2015-01-01

    Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by immune cell infiltration of CNS, blood-brain barrier (BBB) breakdown, localized myelin destruction, and progressive neuronal degeneration. There exists a significant need to identify novel therapeutic targets and strategies that effectively and safely disrupt and even reverse disease pathophysiology. Signaling cascades initiated by semaphorin 4D (SEMA4D) induce glial activation, neuronal process collapse, inhibit migration and differentiation of oligodendrocyte precursor cells (OPCs), and disrupt endothelial tight junctions forming the BBB. To target SEMA4D, we generated a monoclonal antibody that recognizes mouse, rat, monkey and human SEMA4D with high affinity and blocks interaction between SEMA4D and its cognate receptors. In vitro, anti-SEMA4D reverses the inhibitory effects of recombinant SEMA4D on OPC survival and differentiation. In vivo, anti-SEMA4D significantly attenuates experimental autoimmune encephalomyelitis in multiple rodent models by preserving BBB integrity and axonal myelination and can be shown to promote migration of OPC to the site of lesions and improve myelin status following chemically-induced demyelination. Our study underscores SEMA4D as a key factor in CNS disease and supports the further development of antibody-based inhibition of SEMA4D as a novel therapeutic strategy for MS and other neurologic diseases with evidence of demyelination and/or compromise to the neurovascular unit. PMID:25461192

  2. Shuttling protein nucleolin is a microglia receptor for amyloid beta peptide 1-42.

    PubMed

    Ozawa, Daisuke; Nakamura, Takashi; Koike, Masanori; Hirano, Kazuya; Miki, Yuichi; Beppu, Masatoshi

    2013-01-01

    Amyloid-beta peptide 1-42 (Aβ42) plays a key role in the neurotoxicity found in Alzheimer's disease. Mononuclear phagocytes in the brain (microglia), can potentially clear Aβ via phagocytosis. Recently, the shuttling-protein nucleolin has been shown to possess scavenger receptor-activity. Here, we investigated whether this receptor interacts specifically with Aβ type 1-42 and mediates its phagocytosis by microglia. While monomeric and fibril Aβ42 were phagocytosed by mouse microglial EOC2 cells, amyloid β peptide 1-40 (Aβ40) was only weakly phagocytosed. Surface plasmon-resonance analysis revealed that nucleolin strongly associates with Aβ42, but only weakly associates with Aβ40. Immunofluorescence staining of anti-nucleolin antibody revealed that EOC2 cells and rat primary microglia express nucleolin on their cell surfaces. Further, pretreating EOC2 cells with anti-nucleolin antibody, but not immunoglobulin G (IgG), inhibited phagocytosis of monomeric Aβ42 by microglia. Additionally, nucleolin-transfected HEK293 cells phagocytosed monomeric and fibril Aβ42 but not monomeric and fibril Aβ40. Moreover, AGRO, a nucleolin-specific oligonucleotide aptamer, inhibited phagocytosis of monomeric and fibril Aβ42, but not monomeric and fibril Aβ40. These results indicate that nucleolin is a receptor that allows microglia to recognize monomeric and fibril Aβ42. PMID:23912744

  3. Missing and Possible Link between Neuroendocrine Factors, Neuropsychiatric Disorders, and Microglia

    PubMed Central

    Kato, Takahiro A.; Hayakawa, Kohei; Monji, Akira; Kanba, Shigenobu

    2013-01-01

    Endocrine systems have long been suggested to be one of the important factors in neuropsychiatric disorders, while the underlying mechanisms have not been well understood. Traditionally, neuropsychiatric disorders have been mainly considered the consequence of abnormal conditions in neural circuitry. Beyond the neuronal doctrine, microglia, one of the glial cells with inflammatory/immunological functions in the central nervous system (CNS), have recently been suggested to play important roles in neuropsychiatric disorders. However, the crosstalk between neuroendocrine factors, neuropsychiatric disorders, and microglia has been unsolved. Therefore, we herein introduce and discuss a missing and possible link between these three factors; especially highlighting the following hormones; (1) Hypothalamic-Pituitary-Adrenal (HPA) axis-related hormones such as corticotropin-releasing hormone (CRH) and glucocorticoids, (2) sex-related hormones such as estrogen and progesterone, and (3) oxytocin. A growing body of evidence has suggested that these hormones have a direct effect on microglia. We hypothesize that hormone-induced microglial activation and the following microglia-derived mediators may lead to maladaptive neuronal networks including synaptic dysfunctions, causing neuropsychiatric disorders. Future investigations to clarify the correlation between neuroendocrine factors and microglia may contribute to a novel understanding of the pathophysiology of neuropsychiatric disorders. PMID:23874274

  4. Endogenous microglia regulate development of embryonic cortical precursor cells.

    PubMed

    Antony, Joseph M; Paquin, Annie; Nutt, Stephen L; Kaplan, David R; Miller, Freda D

    2011-03-01

    Microglia play important roles in the damaged or degenerating adult nervous system. However, the role of microglia in embryonic brain development is still largely uncharacterized. Here we show that microglia are present in regions of the developing brain that contain neural precursors from E11 onward. To determine whether these microglia are important for neural precursor maintenance or self-renewal, we cultured embryonic neural precursors from the cortex of PU.1(-/-) mice, which we show lack resident microglia during embryogenesis. Cell survival and neurogenesis were similar in cultures from PU.1(-/-) vs. PU.1(+/+) mice, but precursor proliferation and astrogenesis were both reduced. Cortical precursors depleted of microglia also displayed decreased precursor proliferation and astrogenesis, and these deficits could be rescued when microglia were added back to the cultures. Moreover, when the number of microglia present in cortical precursor cultures was increased above normal levels, astrogenesis but not neurogenesis was increased. Together these results demonstrate that microglia present within the embryonic neural precursor niche can regulate neural precursor development and suggest that alterations in microglial number as a consequence of genetic or pathological events could perturb neural development by directly affecting embryonic neural precursors. PMID:21259316

  5. Children's Physical Activity: The Contribution of Playing and Walking

    ERIC Educational Resources Information Center

    Mackett, Roger L.; Paskins, James

    2008-01-01

    This paper draws on research in which 200 children were fitted with motion sensors and asked to keep travel and activity diaries. The findings show that walking and playing away from home can contribute significantly to children's volume of physical activity, with consequent implications for their health. Not only do both playing and walking…

  6. Activated microglia in ischemic stroke penumbra upregulate MCP-1 and CCR2 expression in response to lysophosphatidylcholine derived from adjacent neurons and astrocytes.

    PubMed

    Inose, Yuri; Kato, Yoichiro; Kitagawa, Kazuo; Uchiyama, Shinichiro; Shibata, Noriyuki

    2015-06-01

    In acute stage of ischemic stroke, the surrounding zone of fresh infarcts is termed penumbra, where microglia are activated in response to damaged cell-derived proinflammatory mediators. Rescuing penumbra by regulating inflammatory activity would minimize infarct volume, which positively correlates with functional outcome. To elucidate mechanisms by which inflammation occurs in penumbra, we performed immunohistochemical investigations using autopsied human brains affected by acute, subacute and chronic stages of cerebral infarction as well as cell culture experiments using a murine microglia-derived cell line (BV-2). In penumbra of fresh infarcts, immunoreactivity for secretory phospholipase A2 group X (sPLA2 -X), which is responsible for the production and release of the proinflammatory mediator lysophosphatidylcholine (LPC), was intensely detected in neurons and astrocytes. Furthermore, immunoreactivities for the LPC receptors G protein-coupled receptor 132 (G2A) and P2X purinoreceptor 7 (P2X7R), as well as the CC chemokine monocyte chemoattractant protein-1 (MCP-1) and its receptor CCR2, were detectable in activated microglia. Prior to cell culture experiments, it was confirmed that BV-2 cells were immunoreactive for ionized Ca(2+) -binding adaptor molecule 1 (Iba1), G2A, P2X7R, MCP-1 and CCR2. Reverse transcription-quantitative polymerase chain reaction analysis revealed that MCP-1 and CCR2 mRNA expression levels were significantly increased by LPC stimulation. The LPC-driven increase in MCP-1 transcripts was lowered by blockade of G2A or P2X7R or by inhibition of Rho-associated protein kinase (ROCK) or inhibitor of κBα kinase. The LPC-driven increase in CCR2 transcripts was lowered by blockade of G2A or P2X7R or by inhibition of ROCK, phosphatidylinositide 3-kinanse, extracellular signal-regulated kinase kinase, or p38 mitogen-activated protein kinase. The present results provide in vivo and in vitro evidence that in acute stage of ischemic stroke, the sPLA2

  7. The type 1 Interleukin 1 receptor is not required for the death of murine hippocampal dentate granule cells and microglia activation

    PubMed Central

    Harry, G. Jean; Funk, Jason; Lefebvre d’Hellencourt, Christian; Aoyama, Mineyoshi

    2008-01-01

    Alterations in the inflammatory process, neuronal death, and glia response have been observed under manipulation of the interleukin-1 (IL-1) cytokine and subsequent signaling through the type 1 IL-1 receptor (IL-1R1). To investigate the influence of IL-1R1 activation in the pathophysiology of a chemical-induced injury to the murine hippocampus, we examined the level and pattern of neuronal death and neuroinflammation in 25-day-old male mice exposed to trimethyltin hydroxide (2.0 mg/kg, i.p.). In IL-1R1 null (IL-1R1−/−) mice, the pattern and severity of dentate granule cell death was similar as compared to wild type mice. In both groups of mice, mRNA levels for TNFα and MIP-1α were elevated and the early activation of microglia, including their ability to progress to a phagocytic phenotype, was maintained. Compared to WT mice, IL-1R1−/− mice displayed a limited glial fibrillary acidic protein (GFAP) astrocytic response, as well as a preferential induction in mRNA levels of Fas signaling components. Cumulatively, these results indicate that IL-1R1 activation is not necessary for TMT-induced death of dentate granule neurons or local activation of microglia; however, IL-1R1 signaling is involved in mediating the structural response of astrocytes to injury and may also regulate apoptotic mechanisms by influencing Fas signaling components. PMID:18191113

  8. ROCK inhibition with fasudil promotes early functional recovery of spinal cord injury in rats by enhancing microglia phagocytosis.

    PubMed

    Fu, Pei-cai; Tang, Rong-hua; Wan, Yue; Xie, Min-jie; Wang, Wei; Luo, Xiang; Yu, Zhi-yuan

    2016-02-01

    Emerging evidence indicates that microglia activation plays an important role in spinal cord injury (SCI) caused by trauma. Studies have found that inhibiting the Rho/Rho-associated protein kinase (ROCK) signaling pathway can reduce inflammatory cytokine production by microglia. In this study, Western blotting was conducted to detect ROCK2 expression after the SCI; the ROCK Activity Assay kit was used for assay of ROCK pathway activity; microglia morphology was examined using the CD11b antibody; electron microscopy was used to detect microglia phagocytosis; TUNEL was used to detect tissue cell apoptosis; myelin staining was performed using an antibody against myelin basic protein (MBP); behavioral outcomes were evaluated according to the methods of Basso, Beattie, and Bresnahan (BBB). We observed an increase in ROCK activity and microglial activation after SCI. The microglia became larger and rounder and contained myelin-like substances. Furthermore, treatment with fasudil inhibited neuronal cells apoptosis, alleviated demyelination and the formation of cavities, and improved motor recovery. The experimental evidence reveals that the ROCK inhibitor fasudil can regulate microglial activation, promote cell phagocytosis, and improve the SCI microenvironment to promote SCI repair. Thus, fasudil may be useful for the treatment of SCI. PMID:26838736

  9. Activation of TRPV1 by capsaicin induces functional Kinin B1 receptor in rat spinal cord microglia

    PubMed Central

    2012-01-01

    NMDA receptor (DL-AP5, 10 μg/site, i.t.), substance P NK-1 receptor (RP-67580, 10 μg/site, i.t.) and nitric oxide synthase (L-NNA, 10 μg/site, i.t.). The B1R fluorescent agonist was co-localized with an immunomarker of microglia (Iba-1) in spinal cord dorsal horn of capsaicin-treated rats. Conclusion This study highlights a new mechanism for B1R induction via TRPV1 activation and establishes a link between these two pro-nociceptive receptors in inflammatory pain. PMID:22264228

  10. Electrophysiological and Histological Characterization of Rod-Cone Retinal Degeneration and Microglia Activation in a Mouse Model of Mucopolysaccharidosis Type IIIB.

    PubMed

    Tse, Dennis Y; Lotfi, Parisa; Simons, David L; Sardiello, Marco; Wu, Samuel M

    2015-01-01

    Sanfilippo syndrome Type B or Mucopolysaccharidosis IIIB (MPS IIIB) is a neurodegenerative autosomal recessive lysosomal storage disorder in which patients suffer severe vision loss from associated retinopathy. Here we sought to study the underlying retinal functional and morphological changes associated with MPS IIIB disease progression using the established model of MPS IIIB, the B6.129S6-Naglu(tm1Efn)/J mouse line. Electroretinogram (ERG) was recorded from MPS IIIB and wild-type (WT) mice at the age of 28 and 46 weeks, and retinal tissues were subsequently collected for immunohistochemistry analysis. At the 28th week, rod a- and b-wave amplitudes were significantly diminished in MPS IIIB compared to WT mice. The cone a- and b-waves of MPS IIIB mice were not significantly different from those of the control at the 28th week but were significantly diminished at the 46 th week, when MPS IIIB mice showed a major loss of rods and rod bipolar cells in both central and peripheral regions and a minor loss of cones in the periphery. Activation of microglia and neovascularization were also detected in the MPS IIIB retina. The new findings that cones and rod bipolar cells also undergo degeneration, and that retinal microglia are activated, will inform future development of therapeutic strategies. PMID:26607664

  11. The influence of microglia activation on the efficacy of amitriptyline, doxepin, milnacipran, venlafaxine and fluoxetine in a rat model of neuropathic pain.

    PubMed

    Zychowska, Magdalena; Rojewska, Ewelina; Makuch, Wioletta; Przewlocka, Barbara; Mika, Joanna

    2015-02-15

    The analgesic properties of antidepressants are often used in the treatment of neuropathy; however their influence on glial cells in maintaining neuropathic pain is unknown. Our studies examined the neuropathic pain-relieving properties after intraperitoneal injection of amitriptyline, doxepin, milnacipran, venlafaxine and fluoxetine 7 days after sciatic nerve injury (CCI) in rats and its influence on microglia/macrophages (IBA-1) and astroglia (GFAP) activation in the spinal cord and dorsal root ganglia (DRG) using Western blot. All tested antidepressants significantly reduced CCI-induced allodynia but hyperalgesia was only antagonised by fluoxetine, doxepine and venlafaxine. The strongest analgesia was observed after fluoxetine administration. Western blot analysis showed the upregulation of the IBA-1 in the lumbar spinal cord and DRG after amitriptyline or milnacipran administration in CCI-exposed rats, whereas after fluoxetine the downregulation was observed. The administration of doxepin did not change the IBA-1 protein level in both studied structures; however venlafaxine decreased the IBA-1 only in the DRG. No changes in the GFAP level in both structures were observed after any of listed above antidepressants administration. Chronic minocycline treatment enhanced amitriptyline and milnacipran, but did not fluoxetine analgesia under neuropathic pain in rats. Our results suggest that nerve injury-induced pain is related with the activation of microglia, which is diminished by fluoxetine treatment in the neuropathic pain model. PMID:25460025

  12. Electrophysiological and Histological Characterization of Rod-Cone Retinal Degeneration and Microglia Activation in a Mouse Model of Mucopolysaccharidosis Type IIIB

    PubMed Central

    Tse, Dennis Y.; Lotfi, Parisa; Simons, David L.; Sardiello, Marco; Wu, Samuel M.

    2015-01-01

    Sanfilippo syndrome Type B or Mucopolysaccharidosis IIIB (MPS IIIB) is a neurodegenerative autosomal recessive lysosomal storage disorder in which patients suffer severe vision loss from associated retinopathy. Here we sought to study the underlying retinal functional and morphological changes associated with MPS IIIB disease progression using the established model of MPS IIIB, the B6.129S6-Naglu(tm1Efn)/J mouse line. Electroretinogram (ERG) was recorded from MPS IIIB and wild-type (WT) mice at the age of 28 and 46 weeks, and retinal tissues were subsequently collected for immunohistochemistry analysis. At the 28th week, rod a- and b-wave amplitudes were significantly diminished in MPS IIIB compared to WT mice. The cone a- and b-waves of MPS IIIB mice were not significantly different from those of the control at the 28th week but were significantly diminished at the 46th week, when MPS IIIB mice showed a major loss of rods and rod bipolar cells in both central and peripheral regions and a minor loss of cones in the periphery. Activation of microglia and neovascularization were also detected in the MPS IIIB retina. The new findings that cones and rod bipolar cells also undergo degeneration, and that retinal microglia are activated, will inform future development of therapeutic strategies. PMID:26607664

  13. Superhero Toys and Boys' Physically Active and Imaginative Play

    ERIC Educational Resources Information Center

    Parsons, Amy; Howe, Nina

    2006-01-01

    The influence of superhero versus nonsuperhero toys on boys' physically active and imaginative play was studied in 29 dyads (n = 58 middle-class preschool boys; M age = 54.95 mos, SD = 5.28 mos). Each dyad participated in two play sessions: 1) superhero toys (media related) and 2) nonsuperhero (nonmedia related) toys. Dyads were observed for the…

  14. CHILDREN'S MOVEMENT SKILLS WHEN PLAYING ACTIVE VIDEO GAMES.

    PubMed

    Hulteen, Ryan M; Johnson, Tara M; Ridgers, Nicola D; Mellecker, Robin R; Barnett, Lisa M

    2015-12-01

    Active video games (AVGs) may be useful for movement skill practice. This study examined children's skill execution while playing Xbox Kinect™ and during movement skill assessment. Nineteen children (10 boys, 9 girls; M age=7.9 yr., SD=1.4) had their skills assessed before AVG play and then were observed once a week for 6 wk. while playing AVGs for 50 min. While AVG play showed evidence of correct skill performance (at least 30-50% of the time when playing table tennis, tennis, and baseball), nearly all skills were more correctly performed during skill assessment (generally more than 50% of the time). This study may help researchers to better understand the role AVGs could play in enhancing real life movement skills. PMID:26654991

  15. sTREM2 cerebrospinal fluid levels are a potential biomarker for microglia activity in early-stage Alzheimer's disease and associate with neuronal injury markers.

    PubMed

    Suárez-Calvet, Marc; Kleinberger, Gernot; Araque Caballero, Miguel Ángel; Brendel, Matthias; Rominger, Axel; Alcolea, Daniel; Fortea, Juan; Lleó, Alberto; Blesa, Rafael; Gispert, Juan Domingo; Sánchez-Valle, Raquel; Antonell, Anna; Rami, Lorena; Molinuevo, José L; Brosseron, Frederic; Traschütz, Andreas; Heneka, Michael T; Struyfs, Hanne; Engelborghs, Sebastiaan; Sleegers, Kristel; Van Broeckhoven, Christine; Zetterberg, Henrik; Nellgård, Bengt; Blennow, Kaj; Crispin, Alexander; Ewers, Michael; Haass, Christian

    2016-01-01

    TREM2 is an innate immune receptor expressed on the surface of microglia. Loss-of-function mutations of TREM2 are associated with increased risk of Alzheimer's disease (AD). TREM2 is a type-1 protein with an ectodomain that is proteolytically cleaved and released into the extracellular space as a soluble variant (sTREM2), which can be measured in the cerebrospinal fluid (CSF). In this cross-sectional multicenter study, we investigated whether CSF levels of sTREM2 are changed during the clinical course of AD, and in cognitively normal individuals with suspected non-AD pathology (SNAP). CSF sTREM2 levels were higher in mild cognitive impairment due to AD than in all other AD groups and controls. SNAP individuals also had significantly increased CSF sTREM2 compared to controls. Moreover, increased CSF sTREM2 levels were associated with higher CSF total tau and phospho-tau181P, which are markers of neuronal degeneration and tau pathology. Our data demonstrate that CSF sTREM2 levels are increased in the early symptomatic phase of AD, probably reflecting a corresponding change of the microglia activation status in response to neuronal degeneration. PMID:26941262

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

    SciTech Connect

    Koshida, Ryusuke Oishi, Hisashi 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.

  17. Macrophage subsets and microglia in multiple sclerosis.

    PubMed

    Bogie, Jeroen F J; Stinissen, Piet; Hendriks, Jerome J A

    2014-08-01

    Along with microglia and monocyte-derived macrophages, macrophages in the perivascular space, choroid plexus, and meninges are the principal effector cells in neuroinflammatory and neurodegenerative disorders. These phagocytes are highly heterogeneous cells displaying spatial- and temporal-dependent identities in the healthy, injured, and inflamed CNS. In the last decade, researchers have debated on whether phagocytes subtypes and phenotypes are pathogenic or protective in CNS pathologies. In the context of this dichotomy, we summarize and discuss the current knowledge on the spatiotemporal physiology of macrophage subsets and microglia in the healthy and diseased CNS, and elaborate on factors regulating their behavior. In addition, the impact of macrophages present in lymphoid organs on CNS pathologies is defined. The prime focus of this review is on multiple sclerosis (MS), which is characterized by inflammation, demyelination, neurodegeneration, and CNS repair, and in which microglia and macrophages have been extensively scrutinized. On one hand, microglia and macrophages promote neuroinflammatory and neurodegenerative events in MS by releasing inflammatory mediators and stimulating leukocyte activity and infiltration into the CNS. On the other hand, microglia and macrophages assist in CNS repair through the production of neurotrophic factors and clearance of inhibitory myelin debris. Finally, we define how microglia and macrophage physiology can be harnessed for new therapeutics aimed at suppressing neuroinflammatory and cytodegenerative events, as well as promoting CNS repair. We conclude that microglia and macrophages are highly dynamic cells displaying disease stage and location-specific fates in neurological disorders. Changing the physiology of divergent phagocyte subsets at particular disease stages holds promise for future therapeutics for CNS pathologies. PMID:24952885

  18. Novel endogenous N-acyl amides activate TRPV1-4 receptors, BV-2 microglia, and are regulated in brain in an acute model of inflammation

    PubMed Central

    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

  19. Investigating the role of ankyrin-rich membrane spanning protein in Human Immunodeficiency Virus Type-1 Tat-induced microglia activation

    PubMed Central

    Singh, Vir B.; Wooten, Alicia K.; Jackson, Joseph W.; Maggirwar, Sanjay B.; Kiebala, Michelle

    2015-01-01

    Long-term persistence of Human Immunodeficiency Virus Type-1 (HIV) in the central nervous system (CNS) results in mild to severe neurocognitive impairment in a significant proportion of the HIV infected population. These neurological deficits are known as HIV-Associated Neurocognitive Disorders (HAND). Microglia are CNS resident immune cells that are directly infected by HIV, and consequently secrete proinflammatory molecules that contribute to HIV-induced neuroinflammation. Indeed, the number of activated macrophage and microglia in the brain is more highly correlated with cognitive impairment than the amount of neuronal apoptosis. Ankyrin–rich membrane spanning protein (ARMS/Kidins220) is a multidomain transmembrane protein that is involved with neurotrophin signaling in the CNS. We have previously established the role of ARMS in mediating neuronal survival via a neurotrophin-dependent mechanism. Recent reports also have suggested that ARMS is involved with cell signaling in multiple immune cell types. In this study we aim to investigate the role of ARMS in HIV Tat-mediated microglial cell activation by employing in vitro methods. Following ARMS depletion by a lentivirus encoding ARMS-specific shRNA, we observed a marked reduction in the HIV Tat-induced proinflammatory response, associated with loss of tumor necrosis factor alpha production and nuclear factor-kappa B (NF-κB) activation. Furthermore, co-immunoprecipitation studies suggested that ARMS physically interacts with inhibitory kappa B kinase subunits in order to facilitate NF-κB activation. Our results establish the role of ARMS in microglial activation by HIV Tat and warrant additional studies to better understand these molecular mechanisms, which may uncover novel therapeutic targets for the treatment of HAND. PMID:25636783

  20. A Comprehensive Profile of ChIP-Seq-Based PU.1/Spi1 Target Genes in Microglia

    PubMed Central

    Satoh, Jun-ichi; Asahina, Naohiro; Kitano, Shouta; Kino, Yoshihiro

    2014-01-01

    Microglia are resident mononuclear phagocytes that play a principal role in the maintenance of normal tissue homeostasis in the central nervous system (CNS). Microglia, rapidly activated in response to proinflammatory stimuli, are accumulated in brain lesions of neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. The E26 transformation-specific (ETS) family transcription factor PU.1/Spi1 acts as a master regulator of myeloid and lymphoid development. PU.1-deficient mice show a complete loss of microglia, indicating that PU.1 plays a pivotal role in microgliogenesis. However, the comprehensive profile of PU.1/Spi1 target genes in microglia remains unknown. By analyzing a chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) dataset numbered SRP036026 with the Strand NGS program, we identified 5,264 Spi1 target protein-coding genes in BV2 mouse microglial cells. They included Spi1, Irf8, Runx1, Csf1r, Csf1, Il34, Aif1 (Iba1), Cx3cr1, Trem2, and Tyrobp. By motif analysis, we found that the PU-box consensus sequences were accumulated in the genomic regions surrounding ChIP-Seq peaks. By using pathway analysis tools of bioinformatics, we found that ChIP-Seq-based Spi1 target genes show a significant relationship with diverse pathways essential for normal function of monocytes/macrophages, such as endocytosis, Fc receptor-mediated phagocytosis, and lysosomal degradation. These results suggest that PU.1/Spi1 plays a crucial role in regulation of the genes relevant to specialized functions of microglia. Therefore, aberrant regulation of PU.1 target genes might contribute to the development of neurodegenerative diseases with accumulation of activated microglia. PMID:25574134

  1. Microglia activation in multiple sclerosis black holes predicts outcome in progressive patients: an in vivo [(11)C](R)-PK11195-PET pilot study.

    PubMed

    Giannetti, Paolo; Politis, Marios; Su, Paul; Turkheimer, Federico; Malik, Omar; Keihaninejad, Shiva; Wu, Kit; Reynolds, Richard; Nicholas, Richard; Piccini, Paola

    2014-05-01

    The pathophysiological correlates and the contribution to persisting disability of hypointense T1-weighted MRI lesions, black holes (BH), in multiple sclerosis (MS) are still unclear. In order to study the in vivo functional correlates of this MRI finding, we used 11C-PK11195 PET (PK-PET) to investigate changes in microglial activity. Ten relapsing and 9 progressive MS subjects had a PK-PET scan and a MRI scan alongside a full clinical assessment, including the expanded disability status scale (EDSS) for evaluation of disability. We studied the PK binding potential of the specifically bound radioligand relative to the non-displaceable radioligand in tissue (BPND) in T1 BHs. Out of a total of 1242 BHs identified, 947 were PK enhancing. The PKBPND was correlated with the EDSS (r=0.818; p<0.05) only in the progressive group. In the relapsing patients there was an inverse correlation between PKBPND and BH total lesion volume in whole brain (r=-0.781; p<0.05). When progressive patients were grouped according to the disability outcome at 2years from the PK-PET scan, the total PKBPND in BHs was found to be a significant outcome predictor of disability (p<0.01). Our findings show that relapsing and progressive patients have heterogeneous patterns of PKBPND in T1 BHs and indicate that BHs are not just "holes" representing loss of axons and myelin, but display inflammatory activity in the form of activated microglia. The significant association between PKBPND, neurological impairment and outcome in progressive subjects supports a role for activated microglia in disability progression. PMID:24508617

  2. Engagement, enjoyment, and energy expenditure during active video game play

    PubMed Central

    Lyons, Elizabeth J.; Tate, Deborah F.; Ward, Dianne S.; Ribisl, Kurt M.; Bowling, J. Michael; Kalyanaraman, Sriram

    2014-01-01

    Objective Playing active video games can produce moderate levels of physical activity, but little is known about how these games motivate players to be active. Several psychological predictors, such as perceptions of competence, control, and engagement, may be associated with enjoyment of a game, which has in turn been hypothesized to predict energy expended during play. However, these relationships have yet to be tested in active video games. Methods Young adults aged 18–35 (N = 97, 50 female) < 300 pounds played a Dance Dance Revolution game for 13 minutes while energy expenditure was measured using indirect calorimetry. Self-reported measures of engagement, perceived competence, perceived control, and enjoyment were taken immediately afterwards. Mediation was analyzed using path analysis. Results A path model in which enjoyment mediated the effects of engagement, perceived competence, and perceived control on energy expenditure and BMI directly affected energy expenditure was an adequate fit to the data, χ2(1, N = 97) = .199, p = .655; CFI = 1.00; RMSEA < .001; 90% CI = .000 - .206; p = .692. Enjoyment mediated the relationship between engagement and energy expenditure (indirect effect = .138, p = .028), but other mediated effects were not significant. Conclusion Engagement, enjoyment, and BMI affect energy expended during active video game play. Games that are more enjoyable and engaging may produce greater intensity activity. Developers, practitioners, and researchers should consider characteristics that influence these predictors when creating or recommending active video games. PMID:23527520

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

    PubMed

    Gan, Ping; Zhang, Li; Chen, Yanke; Zhang, Yu; Zhang, Fali; Zhou, Xiang; Zhang, Xiaohu; Gao, Bo; Zhen, Xuechu; Zhang, Jian; Zheng, Long Tai

    2015-05-01

    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. PMID:26003084

  4. Spatial and Cellular Characterization of mTORC1 Activation after Spinal Cord Injury Reveals Biphasic Increase Mainly Attributed to Microglia/Macrophages

    PubMed Central

    Kjell, Jacob; Codeluppi, Simone; Josephson, Anna; Abrams, Mathew B

    2014-01-01

    Mechanistic target of rapamycin complex 1 (mTORC1) is an intracellular kinase complex that regulates energy homeostasis and transcription. Modulation of mTORC1 has proven beneficial in experimental spinal cord injury, making this molecular target a candidate for therapeutic intervention in spinal cord injury. However, both inactivation and activation of mTORC1 have been reported beneficial for recovery. To obtain a more complete picture of mTORC1 activity, we aimed to characterize the spatiotemporal activation pattern of mTORC1 and identify activation in particular cell types after contusion spinal cord injury in rats. To be able to provide a spatial characterization of mTORC1 activation, we monitored activation of downstream target S6. We found robust mTORC1 activation both at the site of injury and in spinal segments rostral and caudal to the injury. There was constitutive mTORC1 activation in neurons that was biphasically reduced caudally after injury. We found biphasic mTORC1 activation in glial cells, primarily activated microglia/macrophages. Furthermore, we found mTORC1 activation in proliferating cells, suggesting this may be a function affected by mTORC1 modulation. Our results reveal potential windows of opportunity for therapeutic interference with mTORC1 signaling and immune cells as targets for inhibition of mTORC1 in spinal cord injury. PMID:24576152

  5. Pycnogenol Attenuates the Release of Proinflammatory Cytokines and Expression of Perilipin 2 in Lipopolysaccharide-Stimulated Microglia in Part via Inhibition of NF-κB and AP-1 Activation.

    PubMed

    Fan, Bin; Dun, Sai-Hong; Gu, Jian-Qiu; Guo, Yang; Ikuyama, Shoichiro

    2015-01-01

    Over activation of microglia results in the production of proinflammatory agents that have been implicated in various brain diseases. Pycnogenol is a patented extract from French maritime pine bark (Pinus pinaster Aiton) with strong antioxidant and anti-inflammatory potency. The present study investigated whether pycnogenol may be associated with the production of proinflammatory mediators in lipopolysaccharide-stimulated BV2 (mouse-derived) microglia. It was found that pycnogenol treatment was dose-dependently associated with significantly less release of nitricoxide (NO), TNF-α, IL-6 and IL-1β, and lower levels of intercellular adhesion molecule1 (ICAM-1) and perilipin 2 (PLIN2). Furthermore, this effect was replicated in primary brain microglia. Levels of inducible NO synthase mRNA and protein were attenuated, whereas there was no change in the production of the anti-inflammatory cytokine IL-10. Further evidence indicated that pycnogenol treatment led to the suppression of NF-κB activation through inhibition of p65 translocation into the nucleus and inhibited DNA binding of AP-1, suggesting that these proinflammatory factors are associated with NF-κB and AP-1. We conclude that pycnogenol exerts anti-inflammatory effects through inhibition of the NF-κB and AP-1pathway, and may be useful as a therapeutic agent in the prevention of diseases caused by over activation of microglia. PMID:26367267

  6. Pycnogenol Attenuates the Release of Proinflammatory Cytokines and Expression of Perilipin 2 in Lipopolysaccharide-Stimulated Microglia in Part via Inhibition of NF-κB and AP-1 Activation

    PubMed Central

    Fan, Bin; Dun, Sai-Hong; Gu, Jian-Qiu; Guo, Yang; Ikuyama, Shoichiro

    2015-01-01

    Over activation of microglia results in the production of proinflammatory agents that have been implicated in various brain diseases. Pycnogenol is a patented extract from French maritime pine bark (Pinus pinaster Aiton) with strong antioxidant and anti-inflammatory potency. The present study investigated whether pycnogenol may be associated with the production of proinflammatory mediators in lipopolysaccharide-stimulated BV2 (mouse-derived) microglia. It was found that pycnogenol treatment was dose-dependently associated with significantly less release of nitricoxide (NO), TNF-α, IL-6 and IL-1β, and lower levels of intercellular adhesion molecule1 (ICAM-1) and perilipin 2 (PLIN2). Furthermore, this effect was replicated in primary brain microglia. Levels of inducible NO synthase mRNA and protein were attenuated, whereas there was no change in the production of the anti-inflammatory cytokine IL-10. Further evidence indicated that pycnogenol treatment led to the suppression of NF-κB activation through inhibition of p65 translocation into the nucleus and inhibited DNA binding of AP-1, suggesting that these proinflammatory factors are associated with NF-κB and AP-1. We conclude that pycnogenol exerts anti-inflammatory effects through inhibition of the NF-κB and AP-1pathway, and may be useful as a therapeutic agent in the prevention of diseases caused by over activation of microglia. PMID:26367267

  7. Influence of playing wind instruments on activity of masticatory muscles.

    PubMed

    Gotouda, A; Yamaguchi, T; Okada, K; Matsuki, T; Gotouda, S; Inoue, N

    2007-09-01

    The aim of this study was to elucidate the influence of change in sound tone of playing wind instruments on activity of jaw-closing muscles and the effect of sustained playing for a long time on fatigue of jaw-closing muscles. Electromyograms (EMG) of 19 brass instrument players and 14 woodwind instrument players were measured while playing instruments in tuning tone and high tone and under other conditions. Nine brass instrument players and nine woodwind instrument players played instruments for 90 min. Before and after the exercise, power spectral analyses of EMG from masseter muscles at 50% of maximum voluntary clenching level were performed and mean power frequency (MPF) were calculated. Root mean square (RMS) of EMG in masseter and temporal muscles while playing were slightly larger than those at rest but extremely small in comparison with those during maximum clenching. Root mean square in orbicularis oris and digastric muscles were relatively large when playing instruments. In the brass instrument group, RMS in high tone was significantly higher than that in tuning tone in all muscles examined. In the woodwind instrument group, RMS in high tone was not significantly higher than that in tuning tone in those muscles. Mean power frequency was not decreased after sustained playing in both instrument groups. These findings indicate that contractive load to jaw-closing muscles when playing a wind instrument in both medium and high tone is very small and playing an instrument for a long time does not obviously induce fatigue of jaw-closing muscles. PMID:17716263

  8. Microglia modulate respiratory rhythm generation and autoresuscitation.

    PubMed

    Lorea-Hernández, Jonathan-Julio; Morales, Teresa; Rivera-Angulo, Ana-Julia; Alcantara-Gonzalez, David; Peña-Ortega, Fernando

    2016-04-01

    Inflammation has been linked to the induction of apneas and Sudden Infant Death Syndrome, whereas proinflammatory mediators inhibit breathing when applied peripherally or directly into the CNS. Considering that peripheral inflammation can activate microglia in the CNS and that this cell type can directly release all proinflammatory mediators that modulate breathing, it is likely that microglia can modulate breathing generation. It might do so also in hypoxia, since microglia are sensitive to hypoxia, and peripheral proinflammatory conditions affect gasping generation and autoresuscitation. Here, we tested whether microglial activation or inhibition affected respiratory rhythm generation. By measuring breathing as well as the activity of the respiratory rhythm generator (the preBötzinger complex), we found that several microglial activators or inhibitors, applied intracisternally in vivo or in the recording bath in vitro, affect the generation of the respiratory rhythms both in normoxia and hypoxia. Furthermore, microglial activation with lipopolysaccharide affected the ability of the animals to autoresuscitate after hypoxic conditions, an effect that is blocked when lipopolysaccharide is co-applied with the microglial inhibitor minocycline. Moreover, we found that the modulation of respiratory rhythm generation induced in vitro by microglial inhibitors was reproduced by microglial depletion. In conclusion, our data show that microglia can modulate respiratory rhythm generation and autoresuscitation. PMID:26678570

  9. Different mechanisms of apolipoprotein E isoform–dependent modulation of prostaglandin E2 production and triggering receptor expressed on myeloid cells 2 (TREM2) expression after innate immune activation of microglia

    PubMed Central

    Li, Xianwu; Montine, Kathleen S.; Keene, C. Dirk; Montine, Thomas J.

    2015-01-01

    Several lines of evidence support immune response in brain as a mechanism of injury in Alzheimer disease (AD). Moreover, immune activation is heightened in apolipoprotein E (APOE) ε4 carriers; inhibitors of prostaglandin (PG) synthesis show a partially protective effect on AD risk from APOE ε4; and genetic variants in triggering receptor expressed on myeloid cells 2 (TREM2) are a rare but potent risk for AD. We tested the hypothesis that APOE ε4 inheritance modulates both the PGE2 pathway and TREM2 expression using primary murine microglia from targeted replacement (TR) APOE3/3 and APOE4/4 mice. Microglial cyclooxygenase-2, microsomal PGE synthase, and PGE2 expression were increased 2- to 25-fold in both genotypes by TLR activators; however, this induction was significantly (P < 0.01) greater in TR APOE4/4 microglia with TLR3 and TLR4 activators. Microglial TREM2 expression was reduced approximately 85% by all TLR activators; this reduction was approximately one-third greater in microglia from TR APOE4/4 mice. Importantly, both receptor-associated protein and a nuclear factor κ-light-chain-enhancer inhibitor blocked TR APOE4/4–dependent effects on the PGE2 pathway but not on TREM2 expression. These data demonstrate complementary, but mechanistically distinct, regulation of pro- and anti-inflammatory mediators in TR APOE4/4 murine microglia that yields a more proinflammatory state than with TR APOE3/3.—Li, X., Montine, K. S., Keene, C. D., Montine, T. J. Different mechanisms of apolipoprotein E isoform–dependent modulation of prostaglandin E2 production and triggering receptor expressed on myeloid cells 2 (TREM2) expression after innate immune activation of microglia. PMID:25593125

  10. Characterizing Newly Repopulated Microglia in the Adult Mouse: Impacts on Animal Behavior, Cell Morphology, and Neuroinflammation

    PubMed Central

    Elmore, Monica R. P.; Lee, Rafael J.; West, Brian L.; Green, Kim N.

    2015-01-01

    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 similarly to the

  11. Should Our Students Pay to Play Extracurricular Activities?

    ERIC Educational Resources Information Center

    Hoff, Dianne L.; Mitchell, Sidney N.

    2007-01-01

    This article talks about the "Pay-to-play" issue in some districts. State constitutions across the nation include guarantees of "free public education." Simply put, that means that school programs may not charge fees for participation. In this article, the authors examine the issue on whether extracurricular activities are integral parts of the…

  12. Gross Activity of Children at Play. (Internal Report).

    ERIC Educational Resources Information Center

    Wuellner, Lance

    Time-lapse photography was used to record the gross play activity of preschool children, rated according to three measures of equipment use and three measures of movement. The definition and derivation of these measures was outlined, and five hypotheses were presented and tested concerning the variability and interrelation of the measures.…

  13. Physical Activity Pattern of Malaysian Preschoolers: Environment, Barriers, and Motivators for Active Play.

    PubMed

    Lee, Shoo Thien; Wong, Jyh Eiin; Ong, Wei Wen; Ismail, Mohd Noor; Deurenberg, Paul; Poh, Bee Koon

    2016-07-01

    Children's physical activity has been correlated with child characteristics and social or physical environment. This study aimed to compare preschoolers' physical activity among various sociodemographic characteristics and to determine barriers, motivators, and environmental factors for active play. A total of 835 preschoolers were included in this analysis. Time spent on active play, quiet play, and screen time was reported by parents. Boys spent significantly more time on active play and screen time than girls. Time spent on quiet play was highest in East Coast Peninsular Malaysia and lowest in Sarawak. Some 40% of children achieved active play recommendation while 27% exceeded daily screen time recommendation. Most parents reported that their child played actively in the house area; and that the main barrier and motivator to active play were safety and child's enjoyment, respectively. These findings demonstrate that sociodemographic characteristics and environment should be considered in designing physical activity intervention programs. PMID:27026634

  14. The Ischemic Environment Drives Microglia and Macrophage Function

    PubMed Central

    Fumagalli, Stefano; Perego, Carlo; Pischiutta, Francesca; Zanier, Elisa R.; De Simoni, Maria-Grazia

    2015-01-01

    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 affect 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 and 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 brain

  15. Function of microglia and macrophages in secondary damage after spinal cord injury

    PubMed Central

    Zhou, Xiang; He, Xijing; Ren, Yi

    2014-01-01

    Spinal cord injury (SCI) is a devastating type of neurological trauma with limited therapeutic opportunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary injury mechanisms, the inflammatory response is the major contributor and results in expansion of the lesion and further loss of neurologic function. Meanwhile, the inflammation directly and indirectly dominates the outcomes of SCI, including not only pain and motor dysfunction, but also preventingneuronal regeneration. Microglia and macrophages play very important roles in secondary injury. Microglia reside in spinal parenchyma and survey the microenvironment through the signals of injury or infection. Macrophages are derived from monocytes recruited to injured sites from the peripheral circulation. Activated resident microglia and monocyte-derived macrophages induce and magnify immune and inflammatory responses not only by means of their secretory moleculesand phagocytosis, but also through their influence on astrocytes, oligodendrocytes and demyelination. In this review, we focus on the roles of microglia and macrophages in secondary injury and how they contribute to the sequelae of SCI. PMID:25422640

  16. SMAD4 is Involved in the Development of Endotoxin Tolerance in Microglia.

    PubMed

    Liu, Xiaorong; Qin, Yongwei; Dai, Aihua; Zhang, Yu; Xue, Huaqing; Ni, Haidan; Han, Lijian; Zhu, Liang; Yuan, Debin; Tao, Tao; Cao, Maohong

    2016-07-01

    Initial exposure of macrophages to LPS induces hyporesponsiveness to a second challenge with LPS, a phenomenon termed LPS tolerance. Smad4 plays important roles in the induction of LPS tolerance. However, the function of Smad4 in microglia remains unknown. Here we show that expression of Smad4 was highly up-regulated in LPS-tolerized mouse cerebral cortex. Smad4 was mostly colocalized with microglia, rarely with neurons. Using a microglia cell line, BV2, we find that LPS activates endogenous Smad4, inducing its migration into the nucleus and increasing its expression. Smad4 significantly suppressed TLR-triggered production of proinflammatory cytokines (IL-6), increased anti-inflammatory cytokine in LPS-tolerized microglia. Moreover, IL-6 concentrations in culture supernatants after second LPS challenge are higher in SMAD4 small interfering RNA (siRNA) BV2 cells than control siRNA BV2 cells, indicating failure to induce tolerance in absence of Smad4 signaling. In our study, we conclude that both in vivo and in vitro, Smad4 signaling is required for maximal induction of endotoxin tolerance. PMID:26758028

  17. Differential roles of astrocyte and microglia in supporting oligodendrocyte development and myelination in vitro

    PubMed Central

    Pang, Yi; Fan, Lir-Wan; Tien, Lu-Tai; Dai, XueMei; Zheng, Baoying; Cai, Zhengwei; Lin, Rick C S; Bhatt, Abhay

    2013-01-01

    Oligodendrocyte (OL) development relies on many extracellular cues, most of which are secreted cytokines from neighboring neural cells. Although it is generally accepted that both astrocytes and microglia are beneficial for OL development, there is a lack of understanding regarding whether astrocytes and microglia play similar or distinct roles. The current study examined the effects of astrocytes and microglia on OL developmental phenotypes including cell survival, proliferation, differentiation, and myelination in vitro. Our data reveal that, although both astrocytes- and microglia-conditioned medium (ACDM and MCDM, respectively) protect OL progenitor cells (OPCs) against growth factor withdrawal-induced apoptosis, ACDM is significantly more effective than MCDM in supporting long-term OL survival. In contrast, MCDM preferentially promotes OL differentiation and myelination. These differential effects of ACDM and MCDM on OL development are highlighted by distinct pattern of cytokine/growth factors in the conditioned medium, which correlates with differentially activated intracellular signaling pathways in OPCs upon exposure to the conditioned medium. PMID:24392271

  18. Energy expended by boys playing active video games.

    PubMed

    White, Kate; Schofield, Grant; Kilding, Andrew E

    2011-03-01

    The purpose of this study was to: (1) determine energy expenditure (EE) during a range of active video games (AVGs) and (2) determine whether EE during AVGs is influenced by gaming experience or fitness. Twenty-six boys (11.4±0.8 years) participated and performed a range of sedentary activities (resting, watching television and sedentary gaming), playing AVGs (Nintendo® Wii Bowling, Boxing, Tennis, and Wii Fit Skiing and Step), walking and running including a maximal fitness test. During all activities, oxygen uptake, heart rate and EE were determined. The AVGs resulted in a significantly higher EE compared to rest (63-190%, p≤0.001) and sedentary screen-time activities (56-184%, p≤0.001). No significant differences in EE were found between the most active video games and walking. There was no evidence to suggest that gaming experience or aerobic fitness influenced EE when playing AVGs. In conclusion, boys expended more energy during active gaming compared to sedentary activities. Whilst EE during AVG is game-specific, AVGs are not intense enough to contribute towards the 60min of daily moderate-to-vigorous physical activity that is currently recommended for children. PMID:20810313

  19. Polyphenols from the stems of Morus alba and their inhibitory activity against nitric oxide production by lipopolysaccharide-activated microglia.

    PubMed

    Rivière, Céline; Krisa, Stéphanie; Péchamat, Laurent; Nassra, Merian; Delaunay, Jean-Claude; Marchal, Axel; Badoc, Alain; Waffo-Téguo, Pierre; Mérillon, Jean-Michel

    2014-09-01

    Neuroinflammatory processes are involved in the pathogenesis of many neurodegenerative disorders. Microglial cells, the main immune cells of the central nervous system, represent a target of interest to search for naturally occurring anti-inflammatory products. In this study, we evaluated the anti-inflammatory properties of polyphenols obtained from the stems of Morus alba. This edible species, known as white mulberry, is frequently studied because of its traditional use in Asian medicine and its richness in different types of polyphenols, some of which are known to be phytoalexins. One new coumarin glycoside, isoscopoletin 6-(6-O-β-apiofuranosyl-β-glucopyranoside) (1) was mainly isolated by CPC (centrifugal partition chromatography) from this plant, together with seven known polyphenols (2-8). Their structures were established on the basis of spectroscopic analyses including extensive 2D NMR studies. The eight isolated compounds were evaluated for their inhibitory activities on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. The absence of cell toxicity is checked by a MTT assay. PMID:24912117

  20. Microglia contribute to circuit defects in Mecp2 null mice independent of microglia-specific loss of Mecp2 expression

    PubMed Central

    Schafer, Dorothy P; Heller, Christopher T; Gunner, Georgia; Heller, Molly; Gordon, Christopher; Hammond, Timothy; Wolf, Yochai; Jung, Steffen; Stevens, Beth

    2016-01-01

    Microglia, the resident CNS macrophages, have been implicated in the pathogenesis of Rett Syndrome (RTT), an X-linked neurodevelopmental disorder. However, the mechanism by which microglia contribute to the disorder is unclear and recent data suggest that microglia do not play a causative role. Here, we use the retinogeniculate system to determine if and how microglia contribute to pathogenesis in a RTT mouse model, the Mecp2 null mouse (Mecp2tm1.1Bird/y). We demonstrate that microglia contribute to pathogenesis by excessively engulfing, thereby eliminating, presynaptic inputs at end stages of disease (≥P56 Mecp2 null mice) concomitant with synapse loss. Furthermore, loss or gain of Mecp2 expression specifically in microglia (Cx3cr1CreER;Mecp2fl/yor Cx3cr1CreER; Mecp2LSL/y) had little effect on excessive engulfment, synapse loss, or phenotypic abnormalities. Taken together, our data suggest that microglia contribute to end stages of disease by dismantling neural circuits rendered vulnerable by loss of Mecp2 in other CNS cell types. DOI: http://dx.doi.org/10.7554/eLife.15224.001 PMID:27458802

  1. Microglia contribute to circuit defects in Mecp2 null mice independent of microglia-specific loss of Mecp2 expression.

    PubMed

    Schafer, Dorothy P; Heller, Christopher T; Gunner, Georgia; Heller, Molly; Gordon, Christopher; Hammond, Timothy; Wolf, Yochai; Jung, Steffen; Stevens, Beth

    2016-01-01

    Microglia, the resident CNS macrophages, have been implicated in the pathogenesis of Rett Syndrome (RTT), an X-linked neurodevelopmental disorder. However, the mechanism by which microglia contribute to the disorder is unclear and recent data suggest that microglia do not play a causative role. Here, we use the retinogeniculate system to determine if and how microglia contribute to pathogenesis in a RTT mouse model, the Mecp2 null mouse (Mecp2(tm1.1Bird/y)). We demonstrate that microglia contribute to pathogenesis by excessively engulfing, thereby eliminating, presynaptic inputs at end stages of disease (≥P56 Mecp2 null mice) concomitant with synapse loss. Furthermore, loss or gain of Mecp2 expression specifically in microglia (Cx3cr1(CreER);Mecp2(fl/y)or Cx3cr1(Cr)(eER); Mecp2(LSL/y)) had little effect on excessive engulfment, synapse loss, or phenotypic abnormalities. Taken together, our data suggest that microglia contribute to end stages of disease by dismantling neural circuits rendered vulnerable by loss of Mecp2 in other CNS cell types. PMID:27458802

  2. Dysfunction of Glutamate Receptors in Microglia May Cause Neurodegeneration.

    PubMed

    Noda, Mami

    2016-01-01

    Dysregulation of glutamate signalling is important in Alzheimer's disease and other pathologies. There has been a focus on changes in neuronal glutamate signalling, but microglia also express glutamate receptors (GluRs), which are known to modulate their responses to neuropathology. Microglia express both metabotropic and ionotropic GluRs. Among ionotropic GluRs, microglial AMPA (α-amino-hydroxy-5-methyl-isoxazole-4-propionate)-type of GluRs (AMPA-Rs) are Ca2+ impermeable due to the expression of subunit GluA2. Upon activation of microglia, expression level of surface GluA2 subunits significantly increase, while expression of GluA1, A3 and A4 subunits on membrane surface significantly decrease. Owing to the GluA2 subunits-dominant composition, AMPA-Rs in activated microglia show little response to Glu. On the other hand, microglia lacking GluA2 show higher Ca(2+)-permeability, consequently inducing a significant increase in the release of the pro-inflammatory cytokine, such as TNF-α. It is suggested that membrane translocation of GluA2-containing AMPA-Rs in activated microglia has functional importance. Thus, dysfunction or decreased expression of GluA2 reported in patients with neurodegenerative diseases such as Alzheimer's and Creutzfeldt-Jakob disease may accelerate Glu neurotoxicity via excess release of proinflammatory cytokines from microglia, causing more neuronal death. PMID:26567741

  3. Grooming and growing with microglia.

    PubMed

    Antony, Joseph Mathew

    2010-01-01

    Microglia mediate neuroprotection and neuropathogenesis but have not been directly associated with behavior. As gatekeepers of the brain's immune system, microglia protect the brain from pathogens but also contribute to inflammation, which may negatively affect neurons. A recent study demonstrates a role for Hoxb8-expressing microglia in modulating behavior, a finding that is interesting from both the pathology and developmental biology perspectives. PMID:21062990

  4. Minocycline Transiently Reduces Microglia/Macrophage Activation but Exacerbates Cognitive Deficits Following Repetitive Traumatic Brain Injury in the Neonatal Rat.

    PubMed

    Hanlon, Lauren A; Huh, Jimmy W; Raghupathi, Ramesh

    2016-03-01

    Elevated microglial/macrophage-associated biomarkers in the cerebrospinal fluid of infant victims of abusive head trauma (AHT) suggest that these cells play a role in the pathophysiology of the injury. In a model of AHT in 11-day-old rats, 3 impacts (24 hours apart) resulted in spatial learning and memory deficits and increased brain microglial/macrophage reactivity, traumatic axonal injury, neuronal degeneration, and cortical and white-matter atrophy. The antibiotic minocycline has been effective in decreasing injury-induced microglial/macrophage activation while simultaneously attenuating cellular and functional deficits in models of neonatal hypoxic ischemia, but the potential for this compound to rescue deficits after impact-based trauma to the immature brain remains unexplored. Acute minocycline administration in this model of AHT decreased microglial/macrophage reactivity in the corpus callosum of brain-injured animals at 3 days postinjury, but this effect was lost by 7 days postinjury. Additionally, minocycline treatment had no effect on traumatic axonal injury, neurodegeneration, tissue atrophy, or spatial learning deficits. Interestingly, minocycline-treated animals demonstrated exacerbated injury-induced spatial memory deficits. These results contrast with previous findings in other models of brain injury and suggest that minocycline is ineffective in reducing microglial/macrophage activation and ameliorating injury-induced deficits following repetitive neonatal traumatic brain injury. PMID:26825312

  5. Running activity profile of adolescent tennis players during match play.

    PubMed

    Hoppe, Matthias W; Baumgart, Christian; Bornefeld, Jutta; Sperlich, Billy; Freiwald, Jürgen; Holmberg, Hans-Christer

    2014-08-01

    The aims of this study were (1) to assess the running activities of adolescent tennis players during match play with respect to velocity, acceleration, and deceleration; (2) to characterize changes in these activities during the course of a match; and (3) to identify potential differences between winners and losers. Twenty well-trained adolescent male athletes (13 ± 1 y) played one simulated match each (giving a total of 10 matches), during which distances covered at different velocity categories (0 to < 1, 1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 m·s(-1)) and number of running activities involving high velocity (≥ 3 m·s(-1)), acceleration (≥ 2 m·s(-2)), and deceleration (≤ -2 m·s(-2)) were monitored using a global positioning system (10 Hz). Heart rate was also assessed. The total match time, total distance covered, peak velocity, and mean heart rate were 81.2 ± 14.6 min, 3362 ± 869 m, 4.4 ± 0.8 m·s(-1), and 159 ± 12 beats·min(-1), respectively. Running activities involving high acceleration (0.6 ± 0.2 n·min(-1)) or deceleration (0.6 ± 0.2 n·min(-1)) were three times as frequent as those involving high velocity (0.2 ± 0.1 n·min(-1)). No change in the pattern of running activities (P ≥ .13, d ≤ 0.39) and no differences between winners and losers (P ≥ .22, d ≤ 0.53) were evident during match play. We conclude that training of well-trained adolescent male tennis players need not focus on further development of their running abilities, since this physical component of multifactorial tennis performance does not change during the course of a match and does not differ between the winners and losers. PMID:25111161

  6. Microglia receptors and their implications in the response to amyloid β for Alzheimer’s disease pathogenesis

    PubMed Central

    2014-01-01

    Alzheimer’s disease (AD) is a major public health problem with substantial economic and social impacts around the world. The hallmarks of AD pathogenesis include deposition of amyloid β (Aβ), neurofibrillary tangles, and neuroinflammation. For many years, research has been focused on Aβ accumulation in senile plaques, as these aggregations were perceived as the main cause of the neurodegeneration found in AD. However, increasing evidence suggests that inflammation also plays a critical role in the pathogenesis of AD. Microglia cells are the resident macrophages of the brain and act as the first line of defense in the central nervous system. In AD, microglia play a dual role in disease progression, being essential for clearing Aβ deposits and releasing cytotoxic mediators. Aβ activates microglia through a variety of innate immune receptors expressed on these cells. The mechanisms through which amyloid deposits provoke an inflammatory response are not fully understood, but it is believed that these receptors cooperate in the recognition, internalization, and clearance of Aβ and in cell activation. In this review, we discuss the role of several receptors expressed on microglia in Aβ recognition, uptake, and signaling, and their implications for AD pathogenesis. PMID:24625061

  7. Image processing methods to elucidate spatial characteristics of retinal microglia after optic nerve transection.

    PubMed

    Zhang, Yudong; Peng, Bo; Wang, Shuihua; Liang, Yu-Xiang; Yang, Jiquan; So, Kwok-Fai; Yuan, Ti-Fei

    2016-01-01

    Microglia are the mononuclear phagocytes with various functions in the central nervous system, and the morphologies of microglia imply the different stages and functions. In optical nerve transection model of the retina, the retrograde degeneration of retinal ganglion cells induces microglial activations to a unique morphology termed rod microglia. A few studies described the rod microglia in the cortex and retina; however, the spatial characteristic of rod microglia is not fully understood. In this study, we built a mathematical model to characterize the spatial trait of rod microglia. In addition, we developed a Matlab-based image processing pipeline that consists of log enhancement, image segmentation, mathematical morphology based cell detection, area calculation and angle analysis. This computer program provides researchers a powerful tool to quickly analyze the spatial trait of rod microglia. PMID:26888347

  8. Image processing methods to elucidate spatial characteristics of retinal microglia after optic nerve transection

    PubMed Central

    Zhang, Yudong; Peng, Bo; Wang, Shuihua; Liang, Yu-Xiang; Yang, Jiquan; So, Kwok-Fai; Yuan, Ti-Fei

    2016-01-01

    Microglia are the mononuclear phagocytes with various functions in the central nervous system, and the morphologies of microglia imply the different stages and functions. In optical nerve transection model of the retina, the retrograde degeneration of retinal ganglion cells induces microglial activations to a unique morphology termed rod microglia. A few studies described the rod microglia in the cortex and retina; however, the spatial characteristic of rod microglia is not fully understood. In this study, we built a mathematical model to characterize the spatial trait of rod microglia. In addition, we developed a Matlab-based image processing pipeline that consists of log enhancement, image segmentation, mathematical morphology based cell detection, area calculation and angle analysis. This computer program provides researchers a powerful tool to quickly analyze the spatial trait of rod microglia. PMID:26888347

  9. Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates

    PubMed Central

    Daniele, Stefano G.; Edwards, Amanda A.; Maguire-Zeiss, Kathleen A.

    2014-01-01

    Isolation of microglia from CNS tissue is a powerful investigative tool used to study microglial biology ex vivo. The present method details a procedure for isolation of microglia from neonatal murine cortices by mechanical agitation with a rotary shaker. This microglia isolation method yields highly pure cortical microglia that exhibit morphological and functional characteristics indicative of quiescent microglia in normal, nonpathological conditions in vivo. This procedure also preserves the microglial immunophenotype and biochemical functionality as demonstrated by the induction of morphological changes, nuclear translocation of the p65 subunit of NF-κB (p65), and secretion of the hallmark proinflammatory cytokine, tumor necrosis factor-α (TNF-α), upon lipopolysaccharide (LPS) and Pam3CSK4 (Pam) challenges. Therefore, the present isolation procedure preserves the immunophenotype of both quiescent and activated microglia, providing an experimental method of investigating microglia biology in ex vivo conditions. PMID:24513797

  10. Microglia participate in neurogenic regulation of hypertension.

    PubMed

    Shen, Xiao Z; Li, You; Li, Liang; Shah, Kandarp H; Bernstein, Kenneth E; Lyden, Patrick; Shi, Peng

    2015-08-01

    Hypertension is associated with neuroinflammation and increased sympathetic tone. Interference with neuroinflammation by an anti-inflammatory reagent or overexpression of interleukin-10 in the brain was found to attenuate hypertension. However, the cellular mechanism of neuroinflammation, as well as its impact on neurogenic regulation of blood pressure, is unclear. Here, we found that hypertension, induced by either angiotensin II or l-N(G)-nitro-l-arginine methyl ester, is accompanied by microglial activation as manifested by microgliosis and proinflammatory cytokine upregulation. Targeted depletion of microglia significantly attenuated neuroinflammation, glutamate receptor expression in the paraventricular nucleus, plasma vasopressin level, kidney norepinephrine concentration, and blood pressure. Furthermore, when microglia were preactivated and transferred into the brains of normotensive mice, there was a significantly prolonged pressor response to intracerebroventricular injection of angiotensin II, and inactivation of microglia eliminated these effects. These data demonstrate that microglia, the resident immune cells in the brain, are the major cellular factors in mediating neuroinflammation and modulating neuronal excitation, which contributes to the elevated blood pressure. PMID:26056339

  11. A Death Trap for Microglia.

    PubMed

    Du, Xu-Fei; Du, Jiu-Lin

    2016-07-25

    Microglia, immune cells of the brain, originate from erythromyeloid precursors, far from the central nervous system. Xu et al. (2016) in this issue of Developmental Cell and Casano et al. (2016) recently in Cell Reports show that apoptotic neurons act as bait to "trap" microglia into colonizing the developing brain. PMID:27459061

  12. Antiprion Activity of DB772 and Related Monothiophene- and Furan-Based Analogs in a Persistently Infected Ovine Microglia Culture System

    PubMed Central

    Dinkel, Kelcey D.; Stanton, James B.; Boykin, David W.; Stephens, Chad E.; Madsen-Bouterse, Sally A.

    2016-01-01

    The transmissible spongiform encephalopathies are fatal neurodegenerative disorders characterized by the misfolding of the native cellular prion protein (PrPC) into the accumulating, disease-associated isoform (PrPSc). Despite extensive research into the inhibition of prion accumulation, no effective treatment exists. Previously, we demonstrated the inhibitory activity of DB772, a monocationic phenyl-furan-benzimidazole, against PrPSc accumulation in sheep microglial cells. In an effort to determine the effect of structural substitutions on the antiprion activity of DB772, we employed an in vitro strategy to survey a library of structurally related, monothiophene- and furan-based compounds for improved inhibitory activity. Eighty-nine compounds were screened at 1 μM for effects on cell viability and prion accumulation in a persistently infected ovine microglia culture system. Eleven compounds with activity equivalent to or higher than that of DB772 were identified as preliminary hit compounds. For the preliminary hits, cytotoxicities and antiprion activities were compared to calculate the tissue culture selectivity index. A structure-activity relationship (SAR) analysis was performed to determine molecular components contributing to antiprion activity. To investigate potential mechanisms of inhibition, effects on PrPC and PrPSc were examined. While inhibition of total PrPC was not observed, the results suggest that a potential target for inhibition at biologically relevant concentrations is through PrPC misfolding to PrPSc. Further, SAR analysis suggests that two structural elements were associated with micromolar antiprion activity. Taken together, the described data provide a foundation for deeper investigation into untested DB compounds and in the design of effective therapeutics. PMID:27381401

  13. Antiprion Activity of DB772 and Related Monothiophene- and Furan-Based Analogs in a Persistently Infected Ovine Microglia Culture System.

    PubMed

    Dinkel, Kelcey D; Stanton, James B; Boykin, David W; Stephens, Chad E; Madsen-Bouterse, Sally A; Schneider, David A

    2016-09-01

    The transmissible spongiform encephalopathies are fatal neurodegenerative disorders characterized by the misfolding of the native cellular prion protein (PrP(C)) into the accumulating, disease-associated isoform (PrP(Sc)). Despite extensive research into the inhibition of prion accumulation, no effective treatment exists. Previously, we demonstrated the inhibitory activity of DB772, a monocationic phenyl-furan-benzimidazole, against PrP(Sc) accumulation in sheep microglial cells. In an effort to determine the effect of structural substitutions on the antiprion activity of DB772, we employed an in vitro strategy to survey a library of structurally related, monothiophene- and furan-based compounds for improved inhibitory activity. Eighty-nine compounds were screened at 1 μM for effects on cell viability and prion accumulation in a persistently infected ovine microglia culture system. Eleven compounds with activity equivalent to or higher than that of DB772 were identified as preliminary hit compounds. For the preliminary hits, cytotoxicities and antiprion activities were compared to calculate the tissue culture selectivity index. A structure-activity relationship (SAR) analysis was performed to determine molecular components contributing to antiprion activity. To investigate potential mechanisms of inhibition, effects on PrP(C) and PrP(Sc) were examined. While inhibition of total PrP(C) was not observed, the results suggest that a potential target for inhibition at biologically relevant concentrations is through PrP(C) misfolding to PrP(Sc) Further, SAR analysis suggests that two structural elements were associated with micromolar antiprion activity. Taken together, the described data provide a foundation for deeper investigation into untested DB compounds and in the design of effective therapeutics. PMID:27381401

  14. Imaging P2X4 Receptor Lateral Mobility in Microglia

    PubMed Central

    Toulme, Estelle; Khakh, Baljit S.

    2012-01-01

    ATP-gated ionotropic P2X4 receptors are up-regulated in activated microglia and are critical for the development of neuropathic pain, a microglia-associated disorder. However, the nature of how plasma membrane P2X4 receptors are regulated in microglia is not fully understood. We used single-molecule imaging to track quantum dot-labeled P2X4 receptors to explore P2X4 receptor mobility in the processes of resting and activated microglia. We find that plasma membrane P2X4 receptor lateral mobility in resting microglial processes is largely random, consisting of mobile and slowly mobile receptors. Moreover, lateral mobility is P2X subunit- and cell-specific, increased in an ATP activation and calcium-dependent manner, and enhanced in activated microglia by the p38 MAPK pathway that selectively regulates slowly mobile receptors. Thus, our data indicate that P2X4 receptors are dynamically regulated mobile ATP sensors, sampling more of the plasma membrane in response to ATP and during the activated state of microglia that is associated with nervous system dysfunction. PMID:22393055

  15. Hepatic ERK activity plays a role in energy metabolism.

    PubMed

    Jiao, Ping; Feng, Bin; Li, Yujie; He, Qin; Xu, Haiyan

    2013-08-15

    Mitogen activated protein kinases (MAPKs), such as c-Jun N-terminal kinase (JNK) and P38, have been reported to play important roles in energy homeostasis. In this study, we show that the activity of extracellular signal-regulated kinase (ERK) is increased in the livers of diet induced and genetically obese mice. Activation of ERK in the livers of lean mice by over-expressing the constitutively active MAPK kinase 1 (MEK CA) results in decreased energy expenditure, lowered expression of genes involved in fatty acid oxidation, increases fasting hyperglycemia and causes systemic insulin resistance. Interestingly, hepatic glycogen content is markedly increased and expression of G6Pase gene is decreased in mice over-expressing MEK CA compared to control mice expressing green fluorescent protein (GFP), therefore hepatic glucose output is not likely the major contributor of hyperglycemia. One potential mechanism of decreased expression of G6Pase gene by MEK CA is likely due to ERK mediated phosphorylation and cytosolic retention of FOXO1. Adipocytes isolated from MEK CA mice display increased lipolysis. Circulating levels of free fatty acids (FFAs) in these mice are also increased, which possibly contribute to systemic insulin resistance and subsequent hyperglycemia. Consistent with these results, knocking down ERK expression in the liver of diet induced obese (DIO) mice improves systemic insulin and glucose tolerance. These results indicate that increased hepatic ERK activity in DIO mice may contribute to increased liver glycogen content and decreased energy expenditure in obesity. PMID:23732116

  16. Relevance of chronic stress and the two faces of microglia in Parkinson’s disease

    PubMed Central

    Herrera, Antonio J.; Espinosa-Oliva, Ana M.; Carrillo-Jiménez, Alejandro; Oliva-Martín, María J.; García-Revilla, Juan; García-Quintanilla, Alberto; de Pablos, Rocío M.; Venero, José L.

    2015-01-01

    This review is aimed to highlight the importance of stress and glucocorticoids (GCs) in modulating the inflammatory response of brain microglia and hence its potential involvement in Parkinson’s disease (PD). The role of inflammation in PD has been reviewed extensively in the literature and it is supposed to play a key role in the course of the disease. Historically, GCs have been strongly associated as anti-inflammatory hormones. However, accumulating evidence from the peripheral and central nervous system have clearly revealed that, under specific conditions, GCs may promote brain inflammation including pro-inflammatory activation of microglia. We have summarized relevant data linking PD, neuroinflamamation and chronic stress. The timing and duration of stress response may be critical for delineating an immune response in the brain thus probably explain the dual role of GCs and/or chronic stress in different animal models of PD. PMID:26321913

  17. The activity intensities reached when playing active tennis gaming relative to sedentary gaming, tennis game-play, and current activity recommendations in young adults.

    PubMed

    Scanlan, Aaron T; Arkinstall, Hayley; Dalbo, Vincent J; Humphries, Brendan J; Jennings, Cameron T; Kingsley, Michael I C

    2013-09-01

    Although active gaming is popular and can increase energy expenditure in young adults, its efficacy as a prescriptive exercise tool is not well understood. This study aimed to: (a) compare the activity intensities experienced by young adults while playing active tennis gaming with conventional sedentary gaming, tennis game-play, and current activity recommendations for health; and (b) identify changes in activity intensities across playing time. After habitualization, 10 active young adults (age: 20.2 ± 0.4 years; stature: 1.74 ± 0.03 m; body mass: 67.7 ± 3.3 kg) completed 3 experimental trials (sedentary gaming, active tennis gaming, and tennis game-play) on separate days in a randomized order. Heart rate (HR) and metabolic equivalents (METs) were averaged across 5 minutes and 10 minutes intervals, and the entire 20 minutes bout within each condition. Active gaming produced greater intensities across 5-10, 10-15, and 15-20 minutes time intervals compared with sedentary gaming (p < 0.01). Tennis game-play elicited greater HR (67 ± 5% HR(max)) and METs (5.0 ± 0.2) responses than both sedentary (40 ± 2% HR(max), 1.1 ± 0.1 METs) and active gaming (45 ± 2% HR(max), 1.4 ± 0.1 METs) (p < 0.001). Only tennis game-play produced activity intensities meeting current recommendations for health benefit. Lower HR intensities were reached across 0-5 minutes than during later time intervals during active gaming (6%) and tennis game-play (9%) (p < 0.01). Activity intensities elicited by active gaming were greater than sedentary gaming but less than tennis game-play and insufficient to contribute toward promoting and maintaining good health in young adults. These data suggest that active tennis gaming should not be recommended by exercise professionals as a substitute for actual sports participation in young adults. PMID:23238089

  18. Metal ions potentiate microglia responsiveness to endotoxin.

    PubMed

    Rachmawati, Dessy; Peferoen, Laura A N; Vogel, Daphne Y S; Alsalem, Inás W A; Amor, Sandra; Bontkes, Hetty J; von Blomberg, B Mary E; Scheper, Rik J; van Hoogstraten, Ingrid M W

    2016-02-15

    Oral metal exposure has been associated with diverse adverse reactions, including neurotoxicity. We showed previously that dentally applied metals activate dendritic cells (MoDC) via TLR4 (Ni, Co, Pd) and TLR3 (Au). It is still unknown whether the low levels of dental metals reaching the brain can trigger local innate cells or prime them to become more responsive. Here we tested whether dentally applied metals (Cr, Fe, Co, Ni, Cu, Zn, Au, Hg) activate primary human microglia in vitro and, as a model, monocytic THP-1-cells, in high non-toxic as well as near-physiological concentrations. In addition the effects of 'near-physiological' metal exposure on endotoxin (LPS) responsiveness of these cells were evaluated. IL-8 and IL-6 production after 24h was used as read out. In high, non-toxic concentrations all transition metals except Cr induced IL-8 and IL-6 production in microglia, with Ni and Co providing the strongest stimulation. When using near-physiological doses (up to 10× the normal plasma concentration), only Zn and Cu induced significant IL-8 production. Of note, the latter metals also markedly potentiated LPS responsiveness of microglia and THP-1 cells. In conclusion, transition metals activate microglia similar to MoDCs. In near-physiological concentrations Zn and Cu are the most effective mediators of innate immune activation. A clear synergism between innate responses to Zn/Cu and LPS was observed, shedding new light on the possible relation between oral metal exposure and neurotoxicity. PMID:26857501

  19. Chronic stress alters the density and morphology of microglia in a subset of stress-responsive brain regions.

    PubMed

    Tynan, Ross J; Naicker, Sundresan; Hinwood, Madeleine; Nalivaiko, Eugene; Buller, Kathryn M; Pow, David V; Day, Trevor A; Walker, Frederick R

    2010-10-01

    The current study, in parallel experiments, evaluated the impact of chronic psychological stress on physiological and behavioural measures, and on the activation status of microglia in 15 stress-responsive brain regions. Rats were subjected, for 14 days, to two 30 min sessions of restraint per day, applied at random times each day. In one experiment the effects of stress on sucrose preference, weight gain, core body temperature, and struggling behaviour during restraint, were determined. In the second experiment we used immunohistochemistry to investigate stress-induced changes in ionized calcium-binding adaptor molecule-1 (Iba1), a marker constitutively expressed by microglia, and major histocompatibility complex-II (MHC-II), a marker often expressed on activated microglia, in a total of 15 stress-responsive nuclei. We also investigated cellular proliferation in these regions using Ki67 immunolabelling, to check for the possibility of microglial proliferation. Collectively, the results we obtained showed that chronic stress induced a significant increase in anhedonia, a decrease in weight gain across the entire observation period, a significant elevation in core body temperature during restraint, and a progressive decrease in struggling behaviour within and over sessions. With regard to microglial activation, chronic stress induced a significant increase in the density of Iba1 immunolabelling (nine of 15 regions) and the number of Iba1-positive cells (eight of 15 regions). Within the regions that exhibited an increased number of Iba1-positive cells after chronic stress, we found no evidence of a between group difference in the number of MHC-II or Ki67 positive cells. In summary, these results clearly demonstrate that chronic stress selectively increases the number of microglia in certain stress-sensitive brain regions, and also causes a marked transition of microglia from a ramified-resting state to a non-resting state. These findings are consistent with the view

  20. ATP increases the migration of microglia across the brain endothelial cell monolayer.

    PubMed

    Maeda, Tomoji; Inagaki, Manato; Fujita, Yu; Kimoto, Takehiro; Tanabe-Fujimura, Chiaki; Zou, Kun; Liu, Junjun; Liu, Shuyu; Komano, Hiroto

    2016-01-01

    The cerebral microcapillary endothelium, known as the blood-brain barrier (BBB), acts as a barrier between the blood and the interstitial fluid of the brain. The BBB therefore controls the passage of nutrients into the central nervous system (CNS). Microglia show a specific affinity for migration into the CNS, and this migration appears to occur independently of BBB integrity. To study the migration of microglia across the BBB, we developed an in vitro co-culture system of mouse brain endothelial cells (MBECs) and Ra2 microglia using Transwell inserts. We first investigated the influence of microglia or ATP, a microglial chemotactic factor, on MBEC barrier integrity. The addition of microglia or ATP led to the disruption of the MBEC monolayer and significantly decreased barrier function as measured by trans-endothelial electrical resistance (TEER) and electric cell-substrate impedance sensing (ECIS). Furthermore, ATP promoted the migration of microglia but not macrophages across the MBEC monolayer. An inhibitor of matrix metalloproteinases (MMPs) decreased the transmigration of microglia in our system, indicating that MMPs play a role in microglial chemotaxis. We specifically identify a role for microglia-derived MMP-2. In conclusion, we offer evidence that microglia migration across the brain endothelial cell monolayer is increased in the presence of ATP in a manner that involves MMP secretion. PMID:26934979

  1. Morphological and Phagocytic Profile of Microglia in the Developing Rat Cerebellum1,2,3

    PubMed Central

    VanRyzin, Jonathan W.

    2015-01-01

    Abstract Microglia are being increasingly recognized as playing important roles in neurodevelopment. The cerebellum matures postnatally, undergoing major growth, but the role of microglia in the developing cerebellum is not well understood. Using the laboratory rat we quantified and morphologically categorized microglia throughout the vermis and across development using a design-based unbiased stereology method. We found that microglial morphology changed from amoeboid to ramified during the first 3 postnatal weeks in a region specific manner. These morphological changes were accompanied by the sudden appearance of phagocytic cups during the third postnatal week from P17 to P19, with an approximately fourfold increase compared with the first week, followed by a prompt decline at the end of the third week. The microglial phagocytic cups were significantly higher in the granular layer (∼69%) than in the molecular layer (ML; ∼31%) during a 3 d window, and present on ∼67% of microglia with thick processes and ∼33% of microglia with thin processes. Similar proportions of phagocytic cups associated to microglia with either thick or thin processes were found in the ML. We observed cell nuclei fragmentation and cleaved caspase-3 expression within some microglial phagocytic cups, presumably from dying granule neurons. At P17 males showed an approximately twofold increase in microglia with thin processes compared with females. Our findings indicate a continuous process of microglial maturation and a nonuniform distribution of microglia in the cerebellar cortex that implicates microglia as an important cellular component of the developing cerebellum. PMID:26464992

  2. Increased tauopathy drives microglia-mediated clearance of beta-amyloid.

    PubMed

    Chen, Wesley; Abud, Edsel A; Yeung, Stephen T; Lakatos, Anita; Nassi, Trevor; Wang, Jane; Blum, David; Buée, Luc; Poon, Wayne W; Blurton-Jones, Mathew

    2016-01-01

    Alzheimer disease is characterized by the accumulation of β-amyloid (Aβ) plaques and tau-laden neurofibrillary tangles. Emerging studies suggest that in neurodegenerative diseases, aggregation of one protein species can promote other proteinopathies and that inflammation plays an important role in this process. To study the interplay between Aβ deposition, tau pathology, and microgliosis, we established a new AD transgenic mouse model by crossing 5xfAD mice with Thy-Tau22 transgenic mice. The resulting 'T5x' mice exhibit a greater than three-fold increase in misfolded and hyperphosphorylated tau and further substantiates the hypothesis that Aβ accelerates tau pathology. Surprisingly, T5x mice exhibit a 40-50 % reduction in Aβ plaque load and insoluble Aβ species when compared with aged-matched 5xfAD littermates. T5x mice exhibit significant changes in cytokine production, an almost doubling of microglial number, and a dramatic shift in microglia activation state. Furthermore, T5x microglia exhibit increased phagocytic capacity that enhances the clearance of insoluble Aβ and decreasing plaque load. Therefore, our results suggest that strategies to increase the phagocytic ability of microglia can be employed to reduce Aβ and that tau-induced changes in microglial activation state can promote the clearance of Aβ. PMID:27339073

  3. Microglia engulf viable newborn cells in the epileptic dentate gyrus.

    PubMed

    Luo, Cong; Koyama, Ryuta; Ikegaya, Yuji

    2016-09-01

    Microglia, which are the brain's resident immune cells, engulf dead neural progenitor cells during adult neurogenesis in the subgranular zone (SGZ) of the dentate gyrus (DG). The number of newborn cells in the SGZ increases significantly after status epilepticus (SE), but whether and how microglia regulate the number of newborn cells after SE remain unclear. Here, we show that microglia rapidly eliminate newborn cells after SE by primary phagocytosis, a process by which viable cells are engulfed, thereby regulating the number of newborn cells that are incorporated into the DG. The number of newborn cells in the DG was increased at 5 days after SE in the adult mouse brain but rapidly decreased to the control levels within a week. During this period, microglia in the DG were highly active and engulfed newborn cells. We found that the majority of engulfed newborn cells were caspase-negative viable cells. Finally, inactivation of microglia with minocycline maintained the increase in the number of newborn cells after SE. Furthermore, minocycline treatment after SE induced the emergence of hilar ectopic granule cells. Thus, our findings suggest that microglia may contribute to homeostasis of the dentate neurogenic niche by eliminating excess newborn cells after SE via primary phagocytosis. GLIA 2016;64:1508-1517. PMID:27301702

  4. Time lapse in vivo microscopy reveals distinct dynamics of microglia-tumor environment interactions-a new role for the tumor perivascular space as highway for trafficking microglia.

    PubMed

    Bayerl, Simon Heinrich; Niesner, Raluca; Cseresnyes, Zoltan; Radbruch, Helena; Pohlan, Julian; Brandenburg, Susan; Czabanka, Marcus Alexander; Vajkoczy, Peter

    2016-07-01

    Microglial cells are critical for glioma growth and progression. However, only little is known about intratumoral microglial behavior and the dynamic interaction with the tumor. Currently the scarce understanding of microglial appearance in malignant gliomas merely originates from histological studies and in vitro investigations. In order to understand the pattern of microglia activity, motility and migration we designed an intravital study in an orthotopic murine glioma model using CX3CR1-eGFP(GFP/wt) mice. We analysed the dynamics of intratumoral microglia accumulation and activity, as well as microglia/tumor blood vessel interaction by epi-illumination and 2-photon laser scanning microscopy. We further investigated cellular and tissue function, including the enzyme activity of intratumoral and microglial NADPH oxidase measured by in vivo fluorescence lifetime imaging. We identified three morphological phenotypes of tumor-associated microglia cells with entirely different motility patterns. We found that NADPH oxidase activation is highly divergent in these microglia subtypes leading to different production levels of reactive oxygen species (ROS). We observed that microglia motility is highest within the perivascular niche, suggesting relevance of microglia/tumor blood vessel interactions. In line, reduction of tumor blood vessels by antivascular therapy confirmed the relevance of the tumor vessel compartment on microglia biology in brain tumors. In summary, we provide new insights into in vivo microglial behavior, regarding both morphology and function, in malignant gliomas. GLIA 2016;64:1210-1226. PMID:27143298

  5. Dynamic changes in pro- and anti-inflammatory cytokines in microglia after PPAR-γ agonist neuroprotective treatment in the MPTPp mouse model of progressive Parkinson's disease.

    PubMed

    Pisanu, Augusta; Lecca, Daniela; Mulas, Giovanna; Wardas, Jadwiga; Simbula, Gabriella; Spiga, Saturnino; Carta, Anna R

    2014-11-01

    Neuroinflammatory changes play a pivotal role in the progression of Parkinson's disease (PD) pathogenesis. Recent findings have suggested that activated microglia may polarize similarly to peripheral macrophages in the central nervous system (CNS), assuming a pro-inflammatory M1 phenotype or the alternative anti-inflammatory M2 phenotype via cytokine production. A skewed M1 activation over M2 has been related to disease progression in Alzheimer disease, and modulation of microglia polarization may be a therapeutic target for neuroprotection. By using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-probenecid (MPTPp) mouse model of progressive PD, we investigated dynamic changes in the production of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β, and anti-inflammatory cytokines, such as transforming growth factor (TGF)-β and IL-10, within Iba-1-positive cells in the substantia nigra compacta (SNc). In addition, to further characterize changes in the M2 phenotype, we measured CD206 in microglia. Moreover, in order to target microglia polarization, we evaluated the effect of the peroxisome-proliferator-activated receptor (PPAR)-γ agonist rosiglitazone, which has been shown to exert neuroprotective effects on nigral dopaminergic neurons in PD models, and acts as a modulator of cytokine production and phenotype in peripheral macrophages. Chronic treatment with MPTPp induced a progressive degeneration of SNc neurons. The neurotoxin treatment was associated with a gradual increase in both TNF-α and IL-1β colocalization with Iba-1-positive cells, suggesting an increase in pro-inflammatory microglia. In contrast, TGF-β colocalization was reduced by the neurotoxin treatment, while IL-10 was mostly unchanged. Administration of rosiglitazone during the full duration of MPTPp treatment reverted both TNF-α and IL-1β colocalization with Iba-1 to control levels. Moreover, rosiglitazone induced an increase in TGF-β and IL-10

  6. Reactive retinal microglia, neuronal survival and the formation of retinal folds and detachments

    PubMed Central

    Fischer, Andy J.; Zelinka, Christopher; Milani-Nejad, Nima

    2014-01-01

    Reactive microglia and macrophages are prevalent in damaged retinas. Accordingly, we investigate how the activation or ablation of microglia/macrophages influences the survival of neurons in the chick retina in vivo. We applied intraocular injections of interleukin 6 (IL6) to stimulate the reactivity of microglia/macrophages and clodronate-liposomes to ablate microglia/macrophages. Activation of the microglia/macrophages with IL6 delays the death of retinal neurons from N-methyl-D-aspartate (NMDA) -induced excitotoxicity. In addition, activation of microglia/macrophages combined with colchicine-mediated retinal damage diminished the survival of ganglion cells. Application of IL6 after an excitotoxic insult greatly exacerbates the damage, and causes widespread retinal detachments and folds, accompanied by accumulation of microglia/macrophages in the subretinal space. Damage-induced retinal folds and detachments were significantly reduced by the ablation of microglia/macrophages. We conclude that microglial reactivity is detrimental to the survival of ganglion cells in colchicine-damaged retinas and detrimental to the survival of photoreceptors in retinal folds. In addition, we conclude that IL6-treatment transiently protects amacrine and bipolar cells against an excitotoxic insult. We propose that suppressing reactivity of microglia/macrophages may be an effective means to lessen the damage and vision loss resulting from damage, in particular during retinal detachment injuries. PMID:25231952

  7. Influence of ball-in-play time on the activity profiles of rugby league match-play.

    PubMed

    Gabbett, Tim J

    2015-03-01

    Most investigations of the activity profiles of rugby league match-play have reported the physical demands across the entire match irrespective of stoppages in play. This study investigated the activity profiles of rugby league match-play, accounting for time when the ball was "in" and "out-of-play." One-hundred four players (mean age, 24.0 ± 3.0 years) from 11 semiprofessional rugby league teams underwent global positioning system analysis during 22 matches. Matches were coded for activity and recovery cycles. Time when the ball was continuously in play was considered activity, whereas any stoppages during the match (e.g., for scrums, penalties, line drop-outs, and tries) were considered recovery. The relative distance (125.1 ± 16.1 m·min vs. 86.7 ± 9.8 m·min), low-speed activity (115.3 ± 15.7 m·min vs. 81.7 ± 9.8 m·min), and high-speed running (9.5 ± 2.9 m·min vs. 5.0 ± 1.8 m·min) demands were significantly (p < 0.0001) higher when accounting for ball-in-play time. The frequency of collisions (0.67 ± 0.28 per minute vs. 0.41 ± 0.17 per minute) and repeated high-intensity effort (RHIE) bouts (1 every 6.1 ± 4.7 minutes vs. 1 every 10.7 ± 8.3 minutes) were also higher when stoppage time was excluded. Large negative correlations (p ≤ 0.001) were found between total ball-in-play time and relative measures of total distance (r = -0.67) and low-speed activity (r = -0.60). These results demonstrate the greater movement, contact, and RHIE demands when rugby league time-motion data are expressed relative to ball-in-play time. Furthermore, the reduction in relative intensity with longer total ball-in-play time suggests that during prolonged passages of play, players adopt a pacing strategy to maintain high-intensity performance and manage fatigue. PMID:25474332

  8. Brain macrophages: evaluation of microglia and their functions.

    PubMed

    Thomas, W E

    1992-01-01

    There is now evidence approaching, if not having already surpassed, overwhelming in support of microglial cells as macrophages. Consistent with this cellular identity, they appear to arise from monocytes in developing brain where amoeboid microglia function in removing cell death-associated debris and in regulating gliogenesis. In normal adult tissue, ramified microglial cells with down-regulated macrophage functional properties may serve a constitutive role in cleansing the extracellular fluid. Under all conditions of brain injury, microglia appear to activate and convert into active macrophages. Activated and reactive microglia participate in inflammation, removal of cellular debris and wound-healing, the latter through regulation of gliosis in scar formation and a potential contribution to neural regeneration and neovascularization. In the activated state, microglia also express MHC's and, thus, may function in antigen presentation and lymphocyte activation for CNS immune responses. As uniquely adapted tissue resident macrophages within the CNS, microglia serve a variety of functional roles over the lifespan of this tissue. These cells may therefore be involved in or contribute to some disease states; such has been indicated in multiple sclerosis and AIDS dementia complex. PMID:1638276

  9. Inhibitory effects of Blueberry Extract on the Production of Inflammatory Mediators in LPS-activated BV2 Microglia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustained microglial activation in the central nervous system (CNS) has been extensively investigated in age-related neurodegenerative diseases and has been postulated to lead to neuronal cell loss in these conditions. Recent studies have shown that anti-inflammatory drugs may suppress microglial ac...

  10. Repurposing psychiatric medicines to target activated microglia in anxious mild cognitive impairment and early Parkinson’s disease

    PubMed Central

    Lauterbach, Edward C

    2016-01-01

    Anxiety is common in the Mild Cognitive Impairment (MCI) stage of Alzheimer’s disease (AD) and the pre-motor stages of Parkinson’s disease (PD). A concomitant and possible cause of this anxiety is microglial activation, also considered a key promoter of neurodegeneration in MCI and early PD via inflammatory mechanisms and the generation of degenerative proinflammatory cytokines. Psychiatric disorders, prevalent in AD and PD, are often treated with psychiatric drugs (psychotropics), raising the question of whether psychotropics might therapeutically affect microglial activation, MCI, and PD. The literature of common psychotropics used in treating psychiatric disorders was reviewed for preclinical and clinical findings regarding microglial activation. Findings potentially compatible with reduced microglial activation or reduced microglial inflammogen release were evident for: antipsychotics including neuroleptics (chlorpromazine, thioridazine, loxapine) and atypicals (aripiprazole, olanzapine, quetiapine, risperidone, ziprasidone); mood stabilizers (carbamazepine, valproate, lithium); antidepressants including tricyclics (amitriptyline, clomipramine, imipramine, nortriptyline), SSRIs (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline), venlafaxine, and bupropion; benzodiazepine anxiolytics (clonazepam, diazepam); cognitive enhancers (donepezil, galantamine, memantine); and other drugs (dextromethorphan, quinidine, amantadine). In contrast, pramipexole and methylphenidate might promote microglial activation. The most promising replicated findings of reduced microglial activation are for quetiapine, valproate, lithium, fluoxetine, donepezil, and memantine but further study is needed and translation of their microglial effects to human disease still requires investigation. In AD-relevant models, risperidone, valproate, lithium, fluoxetine, bupropion, donepezil, and memantine have therapeutic microglial effects in need of replication. Limited

  11. Deacetylation of TFEB promotes fibrillar Aβ degradation by upregulating lysosomal biogenesis in microglia.

    PubMed

    Bao, Jintao; Zheng, Liangjun; Zhang, Qi; Li, Xinya; Zhang, Xuefei; Li, Zeyang; Bai, Xue; Zhang, Zhong; Huo, Wei; Zhao, Xuyang; Shang, Shujiang; Wang, Qingsong; Zhang, Chen; Ji, Jianguo

    2016-06-01

    Microglia play a pivotal role in clearance of Aβ by degrading them in lysosomes, countering amyloid plaque pathogenesis in Alzheimer's disease (AD). Recent evidence suggests that lysosomal dysfunction leads to insufficient elimination of toxic protein aggregates. We tested whether enhancing lysosomal function with transcription factor EB (TFEB), an essential regulator modulating lysosomal pathways, would promote Aβ clearance in microglia. Here we show that microglial expression of TFEB facilitates fibrillar Aβ (fAβ) degradation and reduces deposited amyloid plaques, which are further enhanced by deacetylation of TFEB. Using mass spectrometry analysis, we firstly confirmed acetylation as a previously unreported modification of TFEB and found that SIRT1 directly interacted with and deacetylated TFEB at lysine residue 116. Subsequently, SIRT1 overexpression enhanced lysosomal function and fAβ degradation by upregulating transcriptional levels of TFEB downstream targets, which could be inhibited when TFEB was knocked down. Furthermore, overexpression of deacetylated TFEB at K116R mutant in microglia accelerated intracellular fAβ degradation by stimulating lysosomal biogenesis and greatly reduced the deposited amyloid plaques in the brain slices of APP/PS1 transgenic mice. Our findings reveal that deacetylation of TFEB could regulate lysosomal biogenesis and fAβ degradation, making microglial activation of TFEB a possible strategy for attenuating amyloid plaque deposition in AD. PMID:27209302

  12. Serotonin Modulates Developmental Microglia via 5-HT2B Receptors: Potential Implication during Synaptic Refinement of Retinogeniculate Projections.

    PubMed

    Kolodziejczak, Marta; Béchade, Catherine; Gervasi, Nicolas; Irinopoulou, Theano; Banas, Sophie M; Cordier, Corinne; Rebsam, Alexandra; Roumier, Anne; Maroteaux, Luc

    2015-07-15

    Maturation of functional neuronal circuits during central nervous system development relies on sophisticated mechanisms. First, axonal and dendritic growth should reach appropriate targets for correct synapse elaboration. Second, pruning and neuronal death are required to eliminate redundant or inappropriate neuronal connections. Serotonin, in addition to its role as a neurotransmitter, actively participates in postnatal establishment and refinement of brain wiring in mammals. Brain resident macrophages, that is, microglia, also play an important role in developmentally regulated neuronal death as well as in synaptic maturation and elimination. Here, we tested the hypothesis of cross-regulation between microglia and serotonin during postnatal brain development in a mouse model of synaptic refinement. We found expression of the serotonin 5-HT2B receptor on postnatal microglia, suggesting that serotonin could participate in temporal and spatial synchronization of microglial functions. Using two-photon microscopy, acute brain slices, and local delivery of serotonin, we observed that microglial processes moved rapidly toward the source of serotonin in Htr2B(+/+) mice, but not in Htr2B(-/-) mice lacking the 5-HT2B receptor. We then investigated whether some developmental steps known to be controlled by serotonin could potentially result from microglia sensitivity to serotonin. Using an in vivo model of synaptic refinement during early brain development, we investigated the maturation of the retinal projections to the thalamus and observed that Htr2B(-/-) mice present anatomical alterations of the ipsilateral projecting area of retinal axons into the thalamus. In addition, activation markers were upregulated in microglia from Htr2B(-/-) compared to control neonates, in the absence of apparent morphological modifications. These results support the hypothesis that serotonin interacts with microglial cells and these interactions participate in brain maturation. PMID

  13. Sustained Systemic Glucocerebrosidase Inhibition Induces Brain α-Synuclein Aggregation, Microglia and Complement C1q Activation in Mice

    PubMed Central

    Rocha, Emily M.; Smith, Gaynor A.; Park, Eric; Cao, Hongmei; Graham, Anne-Renee; Brown, Eilish; McLean, Jesse R.; Hayes, Melissa A.; Beagan, Jonathan; Izen, Sarah C.; Perez-Torres, Eduardo

    2015-01-01

    Abstract Aims: Loss-of-function mutations in GBA1, which cause the autosomal recessive lysosomal storage disease, Gaucher disease (GD), are also a key genetic risk factor for the α-synucleinopathies, including Parkinson's disease (PD) and dementia with Lewy bodies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase and reductions in this enzyme result in the accumulation of the glycolipid substrates glucosylceramide and glucosylsphingosine. Deficits in autophagy and lysosomal degradation pathways likely contribute to the pathological accumulation of α-synuclein in PD. In this report we used conduritol-β-epoxide (CBE), a potent selective irreversible competitive inhibitor of glucocerebrosidase, to model reduced glucocerebrosidase activity in vivo, and tested whether sustained glucocerebrosidase inhibition in mice could induce neuropathological abnormalities including α-synucleinopathy, and neurodegeneration. Results: Our data demonstrate that daily systemic CBE treatment over 28 days caused accumulation of insoluble α-synuclein aggregates in the substantia nigra, and altered levels of proteins involved in the autophagy lysosomal system. These neuropathological changes were paralleled by widespread neuroinflammation, upregulation of complement C1q, abnormalities in synaptic, axonal transport and cytoskeletal proteins, and neurodegeneration. Innovation: A reduction in brain GCase activity has been linked to sporadic PD and normal aging, and may contribute to the susceptibility of vulnerable neurons to degeneration. This report demonstrates that systemic reduction of GCase activity using chemical inhibition, leads to neuropathological changes in the brain reminiscent of α-synucleinopathy. Conclusions: These data reveal a link between reduced glucocerebrosidase and the development of α-synucleinopathy and pathophysiological abnormalities in mice, and support the development of GCase therapeutics to reduce α-synucleinopathy in PD and related disorders

  14. Children's Well-Being and Involvement in Physically Active Outdoors Play in a Norwegian Kindergarten: Playful Sharing of Physical Experiences

    ERIC Educational Resources Information Center

    Bjørgen, Kathrine

    2015-01-01

    This qualitative study explores the conditions of children's level of well-being and their involvement in physically active play during kindergarten outdoors time. Observations of three to five year olds from one kindergarten in central Norway were conducted. The researcher followed the children around the kindergarten's outdoors playground and…

  15. HIV-1 Tat disrupts CX3CL1-CX3CR1 axis in microglia via the NF-κB-YY1 pathway

    PubMed Central

    Duan, Ming; Yao, Honghong; Cai, Yu; Liao, Ke; Seth, Pankaj; Buch, Shilpa

    2016-01-01

    Microglia play a central role in the pathogenesis of HIV-associated dementia not only by acting as conduits of viral entry but also as reservoirs for productive and latent virus infection, and as producers of neurotoxins. Interaction between CX3CL1 (fractalkine) and FKN receptor (CX3CR1) is highly functional in the brain, and is known to regulate a complex network of paracrine and autocrine interactions between neurons and microglia. The purpose of the present study was to determine what extent HIV-1 Tat protein causes the alteration of CX3CR1 expression and to investigate the regulatory mechanism for CX3CR1 expression. Here we showed that exposure of primary microglia and BV2 cells to exogenous Tat protein resulted in down-regulation of CX3CR1 expression at both the mRNA and protein levels, with a concomitant induction of proinflammatory responses. Next, we further showed that NF-κB activation by Tat treatment negatively regulated CX3CR1 expression. Since a YY1 binding site ~10kb upstream of CX3CR1 promoter was predicted in rats, mice and humans, the classical NF-κB-YY1 regulatory pathway was considered. Our findings indicated that Tat repressed CX3CR1 expression via NF-κB-YY1 regulatory pathway. To gain insight into the effect of Tat on CX3CL1-CX3CR1 communication, calcium mobilization, MAPK activation and microglial migration, respectively, were tested in microglial cells after successive treatment with Tat and CX3CL1. The results suggested that Tat disrupted the responses of microglia to CX3CL1. Taken together, these results demonstrate that HIV-1 Tat protein suppresses CX3CR1 expression in microglia via NF-κB-YY1 pathway and attenuates CX3CL1-induced functional response of microglia. PMID:24862326

  16. Active Adult Play: Improving Children's Health and Behavior while Having Fun

    ERIC Educational Resources Information Center

    Nelson, Bryan G.; Uba, Gregory

    2009-01-01

    All teachers can be supportive of children's active play by running, jumping, and playing with them and by reducing the time spent simply standing around "supervising" their play. In this article, the authors describe the benefits of active play and offer some encouragement that will get teachers and their coworkers to run around with children.…

  17. The role of microglia and the TLR4 pathway in neuronal apoptosis and vasospasm after subarachnoid hemorrhage

    PubMed Central

    2013-01-01

    Background Although microglia and the Toll-like receptor (TLR) pathway have long been thought to play a role in the pathogenesis of aneurysmal subarachnoid hemorrhage (aSAH), thus far only correlations have been made. In this study, we attempted to solidify the relationship between microglia and the TLR pathway using depletion and genetic knockouts, respectively. Methods Subarachnoid hemorrhage was induced in TLR4−/−, TRIF−/−, MyD88−/− and wild type C57BL/6 mice by injecting 60 μl of autologous blood near the mesencephalon; animals were euthanized 1 to 15 days after SAH for immunohistochemical analysis to detect microglia or apoptotic cells. Lastly, microglial depletion was performed by intracerebroventricular injection of clodronate liposomes. Results On post operative day (POD) 7 (early phase SAH), neuronal apoptosis was largely TLR4-MyD88-dependent and microglial-dependent. By POD 15 (late phase SAH), neuronal apoptosis was characterized by TLR4- toll receptor associated activator of interferon (TRIF)-dependence and microglial-independence. Similarly, vasospasm was also characterized by an early and late phase with MyD88 and TRIF dependence, respectively. Lastly, microglia seem to be both necessary and sufficient to cause vasospasm in both the early and late phases of SAH in our model. Conclusion Our results suggest that SAH pathology could have different phases. These results could explain why therapies tailored to aSAH patients have failed for the most part. Perhaps a novel strategy utilizing immunotherapies that target Toll like receptor signaling and microglia at different points in the patient’s hospital course could improve outcomes. PMID:23849248

  18. Kid's Play. Activities for Adults and the Children They Love.

    ERIC Educational Resources Information Center

    Spanos-Hawkey, Dena, Ed.

    Intended for literacy students who want to share the pleasure of reading with the children they love, this book describes 26 easy, inexpensive activities to expose children to reading. Each activity explains the type of activity, lists materials needed, and provides instructions or suggestions for extending the activity. A suggested book list…

  19. Dissociation of Innate Immune Responses in Microglia Infected with Listeria monocytogenes

    PubMed Central

    Frande-Cabanes, Elisabet; Fernandez-Prieto, Lorena; Calderon-Gonzalez, Ricardo; Rodríguez-Del Río, Estela; Yañez-Diaz, Sonsoles; López-Fanarraga, Monica; Alvarez-Domínguez, Carmen

    2014-01-01

    Microglia, the innate immune cells of the brain, plays a central role in cerebral listeriosis. Here, we present evidence that microglia control Listeria infection differently than macrophages. Infection of primary microglial cultures and murine cell lines with Listeria resulted in a dual function of the two gene expression programmes involved in early and late immune responses in macrophages. Whereas the bacterial gene hly seems responsible for both transcriptional programmes in macrophages, Listeria induces in microglia only the tumor necrosis factor (TNF)-regulated transcriptional programme. Listeria also represses in microglia the late immune response gathered in two clusters, microbial degradation, and interferon (IFN)-inducible genes. The bacterial gene actA was required in microglia to induce TNF-regulated responses and to repress the late response. Isolation of microglial phagosomes revealed a phagosomal environment unable to destroy Listeria. Microglial phagosomes were also defective in several signaling and trafficking components reported as relevant for Listeria innate immune responses. This transcriptional strategy in microglia induced high levels of TNF-α and monocyte chemotactic protein-1 and low production of other neurotoxic compounds such as nitric oxide, hydrogen peroxide, and Type I IFNs. These cytokines and toxic microglial products are also released by primary microglia, and this cytokine and chemokine cocktail display a low potential to trigger neuronal apoptosis. This overall bacterial strategy strongly suggests that microglia limit Listeria inflammation pattern exclusively through TNF-mediated responses to preserve brain integrity. GLIA 2014;62:233–246 PMID:24311463

  20. Dissociation of innate immune responses in microglia infected with Listeria monocytogenes.

    PubMed

    Frande-Cabanes, Elisabet; Fernandez-Prieto, Lorena; Calderon-Gonzalez, Ricardo; Rodríguez-Del Río, Estela; Yañez-Diaz, Sonsoles; López-Fanarraga, Monica; Alvarez-Domínguez, Carmen

    2014-02-01

    Microglia, the innate immune cells of the brain, plays a central role in cerebral listeriosis. Here, we present evidence that microglia control Listeria infection differently than macrophages. Infection of primary microglial cultures and murine cell lines with Listeria resulted in a dual function of the two gene expression programmes involved in early and late immune responses in macrophages. Whereas the bacterial gene hly seems responsible for both transcriptional programmes in macrophages, Listeria induces in microglia only the tumor necrosis factor (TNF)-regulated transcriptional programme. Listeria also represses in microglia the late immune response gathered in two clusters, microbial degradation, and interferon (IFN)-inducible genes. The bacterial gene actA was required in microglia to induce TNF-regulated responses and to repress the late response. Isolation of microglial phagosomes revealed a phagosomal environment unable to destroy Listeria. Microglial phagosomes were also defective in several signaling and trafficking components reported as relevant for Listeria innate immune responses. This transcriptional strategy in microglia induced high levels of TNF-α and monocyte chemotactic protein-1 and low production of other neurotoxic compounds such as nitric oxide, hydrogen peroxide, and Type I IFNs. These cytokines and toxic microglial products are also released by primary microglia, and this cytokine and chemokine cocktail display a low potential to trigger neuronal apoptosis. This overall bacterial strategy strongly suggests that microglia limit Listeria inflammation pattern exclusively through TNF-mediated responses to preserve brain integrity. PMID:24311463

  1. Elimination of microglia improves cognitive function following cranial irradiation

    PubMed Central

    Acharya, Munjal M.; Green, Kim N.; Allen, Barrett D.; Najafi, Allison R.; Syage, Amber; Minasyan, Harutyun; Le, Mi T.; Kawashita, Takumi; Giedzinski, Erich; Parihar, Vipan K.; West, Brian L.; Baulch, Janet E.; Limoli, Charles L.

    2016-01-01

    Cranial irradiation for the treatment of brain cancer elicits progressive and severe cognitive dysfunction that is associated with significant neuropathology. Radiation injury in the CNS has been linked to persistent microglial activation, and we find upregulation of pro-inflammatory genes even 6 weeks after irradiation. We hypothesize that depletion of microglia in the irradiated brain would have a neuroprotective effect. Adult mice received acute head only irradiation (9 Gy) and were administered a dietary inhibitor (PLX5622) of colony stimulating factor-1 receptor (CSF1R) to deplete microglia post-irradiation. Cohorts of mice maintained on a normal and PLX5662 diet were analyzed for cognitive changes using a battery of behavioral tasks 4–6 weeks later. PLX5622 treatment caused a rapid and near complete elimination of microglia in the brain within 3 days of treatment. Irradiation of animals given a normal diet caused characteristic behavioral deficits designed to test medial pre-frontal cortex (mPFC) and hippocampal learning and memory and caused increased microglial activation. Animals receiving the PLX5622 diet exhibited no radiation-induced cognitive deficits, and exhibited near complete loss of IBA-1 and CD68 positive microglia in the mPFC and hippocampus. Our data demonstrate that elimination of microglia through CSF1R inhibition can ameliorate radiation-induced cognitive deficits in mice. PMID:27516055

  2. Aging-like Changes in the Transcriptome of Irradiated Microglia

    PubMed Central

    Li, Matthew D.; Burns, Terry C.; Kumar, Sunny; Morgan, Alexander A.; Sloan, Steven A.; Palmer, Theo D.

    2014-01-01

    Whole brain irradiation remains important in the management of brain tumors. Although necessary for improving survival outcomes, cranial irradiation also results in cognitive decline in long-term survivors. A chronic inflammatory state characterized by microglial activation has been implicated in radiation-induced brain injury. We here provide the first comprehensive transcriptional profile of irradiated microglia. Fluorescence-activated cell sorting (FACS) was used to isolate CD11b+ microglia from the hippocampi of C57BL/6 and Balb/c mice 1 month after 10Gy cranial irradiation. Affymetrix gene expression profiles were evaluated using linear modeling, rank product analyses. One month after irradiation, a conserved irradiation signature across strains was identified, comprising 448 and 85 differentially up- and down-regulated genes, respectively. Gene set enrichment analysis (GSEA) demonstrated enrichment for inflammation, including M1 macrophage-associated genes, but also an unexpected enrichment for extracellular matrix and blood coagulation-related gene sets, in contrast previously described microglial states. Weighted gene co-expression network analysis (WGCNA) confirmed these findings and further revealed alterations in mitochondrial function. The RNA-seq transcriptome of microglia 24h post-radiation proved similar to the 1-month transcriptome, but additionally featured alterations in apoptotic and lysosomal gene expression. Re-analysis of published aging mouse microglia transcriptome data demonstrated striking similarity to the 1 month irradiated microglia transcriptome, suggesting that shared mechanisms may underlie aging and chronic irradiation-induced cognitive decline. PMID:25690519

  3. Elimination of microglia improves cognitive function following cranial irradiation.

    PubMed

    Acharya, Munjal M; Green, Kim N; Allen, Barrett D; Najafi, Allison R; Syage, Amber; Minasyan, Harutyun; Le, Mi T; Kawashita, Takumi; Giedzinski, Erich; Parihar, Vipan K; West, Brian L; Baulch, Janet E; Limoli, Charles L

    2016-01-01

    Cranial irradiation for the treatment of brain cancer elicits progressive and severe cognitive dysfunction that is associated with significant neuropathology. Radiation injury in the CNS has been linked to persistent microglial activation, and we find upregulation of pro-inflammatory genes even 6 weeks after irradiation. We hypothesize that depletion of microglia in the irradiated brain would have a neuroprotective effect. Adult mice received acute head only irradiation (9 Gy) and were administered a dietary inhibitor (PLX5622) of colony stimulating factor-1 receptor (CSF1R) to deplete microglia post-irradiation. Cohorts of mice maintained on a normal and PLX5662 diet were analyzed for cognitive changes using a battery of behavioral tasks 4-6 weeks later. PLX5622 treatment caused a rapid and near complete elimination of microglia in the brain within 3 days of treatment. Irradiation of animals given a normal diet caused characteristic behavioral deficits designed to test medial pre-frontal cortex (mPFC) and hippocampal learning and memory and caused increased microglial activation. Animals receiving the PLX5622 diet exhibited no radiation-induced cognitive deficits, and exhibited near complete loss of IBA-1 and CD68 positive microglia in the mPFC and hippocampus. Our data demonstrate that elimination of microglia through CSF1R inhibition can ameliorate radiation-induced cognitive deficits in mice. PMID:27516055

  4. CX3CR1 in microglia regulates brain amyloid deposition through selective protofibrillar Aβ phagocytosis

    PubMed Central

    Liu, Zhiqiang; Condello, Carlo; Schain, Aaron; Harb, Roa; Grutzendler, Jaime

    2010-01-01

    In Alzheimer’s disease (AD), amyloid-β (Aβ) deposits are frequently surrounded by activated microglia but the precise role of these cells in disease progression remains unclear. The chemokine receptor CX3CR1 is selectively expressed in microglia and is thought to modulate their activity. To study the specific effects of microglia activation on amyloid pathology in vivo, we crossbred mice lacking CX3CR1 with the Alzheimer’s mouse model CRND8. Surprisingly, we found that CX3CR1 deficient mice had lower brain levels of Aβ40 and Aβ42 and reduced amyloid deposits. Quantification of Aβ within microglia and time-lapse two photon microscopy in live mice revealed that these cells were highly effective at the uptake of protofibrillar amyloid but were incapable of phagocytosis of fibrillar congophilic Aβ. CX3CR1 deletion was associated with increased phagocytic ability which led to greater amyloid content within microglial phagolysosomes. Furthermore, CX3CR1 deficient mice had an increased number of microglia around individual plaques due to higher proliferative rates, which likely contributed to an overall greater phagocytic capacity. CX3CR1 deletion did not affect the degree of neuronal or synaptic damage around plaques despite increased microglia density. Our results demonstrate that microglia can regulate brain Aβ levels and plaque deposition via selective protofibrillar Aβ phagocytosis. Modulation of microglia activity and proliferation by CX3CR1 signaling may represent a therapeutic strategy for AD. PMID:21159979

  5. Microglia recapitulate a hematopoietic master regulator network in the aging human frontal cortex

    PubMed Central

    Wehrspaun, Claudia C.; Haerty, Wilfried; Ponting, Chris P.

    2015-01-01

    Microglia form the immune system of the brain. Previous studies in cell cultures and animal models suggest altered activation states and cellular senescence in the aged brain. Instead, we analyzed 3 transcriptome data sets from the postmortem frontal cortex of 381 control individuals to show that microglia gene markers assemble into a transcriptional module in a gene coexpression network. These markers predominantly represented M1 and M1/M2b activation phenotypes. Expression of genes in this module generally declines over the adult life span. This decrease was more pronounced in microglia surface receptors for microglia and/or neuron crosstalk than in markers for activation state phenotypes. In addition to these receptors for exogenous signals, microglia are controlled by brain-expressed regulatory factors. We identified a subnetwork of transcription factors, including RUNX1, IRF8, PU.1, and TAL1, which are master regulators (MRs) for the age-dependent microglia module. The causal contributions of these MRs on the microglia module were verified using publicly available ChIP-Seq data. Interactions of these key MRs were preserved in a protein-protein interaction network. Importantly, these MRs appear to be essential for regulating microglia homeostasis in the adult human frontal cortex in addition to their crucial roles in hematopoiesis and myeloid cell-fate decisions during embryogenesis. PMID:26002684

  6. Microglia recapitulate a hematopoietic master regulator network in the aging human frontal cortex.

    PubMed

    Wehrspaun, Claudia C; Haerty, Wilfried; Ponting, Chris P

    2015-08-01

    Microglia form the immune system of the brain. Previous studies in cell cultures and animal models suggest altered activation states and cellular senescence in the aged brain. Instead, we analyzed 3 transcriptome data sets from the postmortem frontal cortex of 381 control individuals to show that microglia gene markers assemble into a transcriptional module in a gene coexpression network. These markers predominantly represented M1 and M1/M2b activation phenotypes. Expression of genes in this module generally declines over the adult life span. This decrease was more pronounced in microglia surface receptors for microglia and/or neuron crosstalk than in markers for activation state phenotypes. In addition to these receptors for exogenous signals, microglia are controlled by brain-expressed regulatory factors. We identified a subnetwork of transcription factors, including RUNX1, IRF8, PU.1, and TAL1, which are master regulators (MRs) for the age-dependent microglia module. The causal contributions of these MRs on the microglia module were verified using publicly available ChIP-Seq data. Interactions of these key MRs were preserved in a protein-protein interaction network. Importantly, these MRs appear to be essential for regulating microglia homeostasis in the adult human frontal cortex in addition to their crucial roles in hematopoiesis and myeloid cell-fate decisions during embryogenesis. PMID:26002684

  7. Nurr1 expression is modified by inflammation in microglia.

    PubMed

    Lallier, Scott W; Graf, Amanda E; Waidyarante, Gavisha R; Rogers, Lynette K

    2016-10-19

    Advances in neonatal care have allowed premature infants to survive at earlier gestational ages, but they are often afflicted with neurological delays or deficits. Maternal inflammation has been identified as a major risk factor for premature birth and once born, infants often require supplemental oxygen for survival. Nurr1 (NR4A2) is an orphan nuclear receptor with no known binding site and is essential for the growth of midbrain dopamine neurons. Others have reported that Nurr1 can act as an anti-inflammatory transcription factor in microglia and astrocytes and respond lipopolysaccharide (LPS). We have previously reported decreased numbers of oligodendrocytes and increased numbers of microglia in the mice exposed to both maternal inflammation and neonatal hyperoxia in the perinatal period. These studies tested the hypothesis that the combined exposures to inflammation and hyperoxia would increase Nurr1 expression in microglia in our mouse model and in an immortalized microglia cell line, BV2 cells. Our data indicate that Nurr1 protein expression is increased at postnatal day 0 and postnatal day 28 in whole-brain homogenates from mice exposed to LPS and hyperoxia. Alternatively, Nurr1 message is decreased at postnatal day 60 in isolated microglia, indicating that the increases in whole-brain homogenates may be due to other cell types. In BV2 cells, Nurr1 message in increased by exposure to hyperoxia, but this increase is attenuated in cells exposed to both LPS and hyperoxia. Although Nurr1 regulation is not straightforward, these data indicate that Nurr1 expression is increased in whole-brain homogenates in response to inflammation, but is decreased in isolated primary microglia and BV2 cells in response to similar inflammation. Our data support the hypothesis that Nurr1 expression may play a significant role in regulating inflammation in the brain and understanding the complex regulation of Nurr1 could lead to new therapeutic strategies. PMID:27532877

  8. Serotonin stimulates secretion of exosomes from microglia cells.

    PubMed

    Glebov, Konstantin; Löchner, Marie; Jabs, Ronald; Lau, Thorsten; Merkel, Olaf; Schloss, Patrick; Steinhäuser, Christian; Walter, Jochen

    2015-04-01

    Microglia are resident immune cells in the brain and exert important functions in the regulation of inflammatory processes during infection or cellular damage. Upon activation, microglia undergo complex morphological and functional transitions, including increased motility, phagocytosis and cytokine secretion. Recent findings indicate that exosomes, small vesicles that derive from fusion of multivesicular bodies with the plasma membrane, are involved in secretion of certain cytokines. The presence of specific receptors on the surface of microglia suggests communication with neurons by neurotransmitters. Here, we demonstrate expression of serotonin receptors, including 5-HT2a,b and 5-HT4 in microglial cells and their functional involvement in the modulation of exosome release by serotonin. Our data demonstrate the involvement of cAMP and Ca(2+) dependent signaling pathways in the regulation of exosome secretion. Co-culture of microglia with embryonic stem cell-derived serotonergic neurons further demonstrated functional signaling between neurons and microglia. Together, these data provide evidence for neurotransmitter-dependent signaling pathways in microglial cells that regulate exosome release. PMID:25451814

  9. Microglia in dementia with Lewy bodies.

    PubMed

    Streit, Wolfgang J; Xue, Qing-Shan

    2016-07-01

    Microglial activation (neuroinflammation) is often cited as a pathogenic factor in the development of neurodegenerative diseases. However, there are significant caveats associated with the idea that inflammation directly causes either α-synuclein pathology or neurofibrillary degeneration (NFD). We have performed immunohistochemical studies on microglial cells in five cases of dementia with Lewy bodies (DLB), median age 87, and nine cases of non-demented (ND) controls, median age 74, using tissue samples from the temporal lobe and the superior frontal gyrus. Three different antibodies known to label microglia and macrophages were employed: iba1, anti-CD68, and anti-ferritin. All DLB cases showed both α-synuclein pathology (Lewy bodies and neurites) and NFD ranging from Braak stage II to IV. In contrast, all controls were devoid of α-synuclein pathology but did show NFD ranging from Braak stage I to III. Using iba1 labeling, our current results show a notable absence of activated microglia in all cases with the exception of two controls that showed small focal areas of microglial activation and macrophage formation. Both iba1 and ferritin antibodies revealed a mixture of ramified and dystrophic microglial cells throughout the regions examined, and there were no measurable differences in the prevalence of dystrophic microglial cells between DLB and controls. Double-labeling for α-synuclein and iba1-positive microglia showed that cortical Lewy bodies were surrounded by both ramified and dystrophic microglial cells. We found an increase in CD68 expression in DLB cases relative to controls. Since microglial dystrophy has been linked to NFD and since it did not appear to be worse in DLB cases over controls, our findings support the idea that the additional Lewy body pathology in DLB is not the result of intensified microglial dystrophy. CD68 is likely associated with lipofuscin deposits in microglial cells which may be increased in DLB cases because of impaired

  10. Piano Playing Reduces Stress More than Other Creative Art Activities

    ERIC Educational Resources Information Center

    Toyoshima, Kumiko; Fukui, Hajime; Kuda, Kiyoto

    2011-01-01

    Few studies have been conducted on the physiological effects of creative art activities. In this study, the effects of creative art activities on human stress were investigated, and their effects were compared in 57 healthy college students (27 males and 30 females). Subjects were divided into four groups, each of which participated in 30-minute…

  11. Spondylolysis in Active Adolescents: Expediting Return to Play.

    ERIC Educational Resources Information Center

    Moeller, James L.; Rifat, Sami F.

    2001-01-01

    Spondylolysis is a common cause of back pain in active adolescents. For prolonged pain, an aggressive workup and specific diagnosis are needed. History and physical exam findings are not diagnostic. Tests beyond radiographs (computed tomography, bone scans, and magnetic resonance imaging) are necessary to determine metabolic activity and full…

  12. "LET US Play": Maximizing Physical Activity "in" Physical Education

    ERIC Educational Resources Information Center

    Weaver, R. Glenn; Webster, Collin; Beets, Michael W.

    2013-01-01

    Schools have been identified as a promising setting for increasing youth physical activity levels because of their broad reach and the amount of time youth spend in attendance. Specifically, physical education is one key time during the school day where youth can accumulate health-enhancing levels of physical activity. Indicators of quality…

  13. Role of microglia in embryonic neurogenesis

    PubMed Central

    Tong, Chih Kong

    2016-01-01

    Microglia begin colonizing the developing brain as early as embryonic day 9, prior to the emergence of neurons and other glia. Their ontogeny is also distinct from other central nervous system cells, as they derive from yolk sac hematopoietic progenitors and not neural progenitors. In this review, we feature these unique characteristics of microglia and assess the spatiotemporal similarities between microglia colonization of the central nervous system and embryonic neurogenesis. We also infer to existing evidence for microglia function from embryonic through to postnatal neurodevelopment to postulate roles for microglia in neurogenesis. PMID:27555616

  14. Role of microglia in embryonic neurogenesis.

    PubMed

    Tong, Chih Kong; Vidyadaran, Sharmili

    2016-09-01

    Microglia begin colonizing the developing brain as early as embryonic day 9, prior to the emergence of neurons and other glia. Their ontogeny is also distinct from other central nervous system cells, as they derive from yolk sac hematopoietic progenitors and not neural progenitors. In this review, we feature these unique characteristics of microglia and assess the spatiotemporal similarities between microglia colonization of the central nervous system and embryonic neurogenesis. We also infer to existing evidence for microglia function from embryonic through to postnatal neurodevelopment to postulate roles for microglia in neurogenesis. PMID:27555616

  15. Footballs versus Barbies: Childhood Play Activities as Predictors of Sport Participation by Women.

    ERIC Educational Resources Information Center

    Guiliano, Traci A.; Popp, Kathryn E.; Knight, Jennifer L.

    2000-01-01

    Examined the extent to which women's childhood play activities predicted future sport participation. College athletes and nonathletes completed a survey on childhood play and adult sports experiences. Playing with masculine toys and games, playing in predominantly male or mixed groups, and being a tomboy characterized women who later became…

  16. A neuroprotective role for microglia in prion diseases.

    PubMed

    Zhu, Caihong; Herrmann, Uli S; Falsig, Jeppe; Abakumova, Irina; Nuvolone, Mario; Schwarz, Petra; Frauenknecht, Katrin; Rushing, Elisabeth J; Aguzzi, Adriano

    2016-05-30

    Microglial activation is a hallmark of most neurodegenerative disorders, and is particularly conspicuous in prion diseases. However, the role of microglia, which function as both primary immune effector cells and professional phagocytes in the central nervous system, remains contentious in the context of neurodegeneration. Here, we evaluated the effect of microglial depletion/deficiency on prion pathogenesis. We found that ganciclovir-mediated microglial ablation on tga20/CD11b-thymidine kinase of Herpes simplex virus (HSVTK) cerebellar organotypic cultured slices markedly aggravated prion-induced neurotoxicity. A similar deterioration of disease was recapitulated in in vivo microglial depletion in prion-infected tga20/CD11b-HSVTK mice. Additionally, deficiency of microglia in interleukin 34 knockout (IL34(-/-)) mice again resulted in significantly augmented proteinase K-resistant prion protein deposition and accelerated prion disease progression. These results provide unambiguous evidence for a general protective role of microglia in prion pathogenesis. PMID:27185853

  17. Contribution of Microglia-Mediated Neuroinflammation to Retinal Degenerative Diseases

    PubMed Central

    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. PMID:25873768

  18. Microglia in the pathogenesis of autism spectrum disorders.

    PubMed

    Koyama, Ryuta; Ikegaya, Yuji

    2015-11-01

    Proper synaptic pruning is essential for the development of functional neural circuits. Impairments in synaptic pruning disrupt the excitatory versus inhibitory balance (E/I balance) of synapses, which may cause neurodevelopmental disorders such as autism spectrum disorder (ASD). Recent studies have determined molecular mechanisms by which microglia, the brain's resident immune cells, engulf inappropriate and less active synapses. Thus, microglial dysfunction may be involved in the pathogenesis of ASD through attenuated or excess synaptic pruning. In this review, we discuss recent animal and human studies that report an E/I imbalance and the characteristics of microglia in ASD. We will further discuss whether and how synaptic pruning by microglia is involved in the pathogenesis of ASD. PMID:26116891

  19. Microglia toxicity in preterm brain injury

    PubMed Central

    Baburamani, Ana A.; Supramaniam, Veena G.; Hagberg, Henrik; Mallard, Carina

    2014-01-01

    Microglia are the resident phagocytic cells of the central nervous system. During brain development they are also imperative for apoptosis of excessive neurons, synaptic pruning, phagocytosis of debris and maintaining brain homeostasis. Brain damage results in a fast and dynamic microglia reaction, which can influence the extent and distribution of subsequent neuronal dysfunction. As a consequence, microglia responses can promote tissue protection and repair following brain injury, or become detrimental for the tissue integrity and functionality. In this review, we will describe microglia responses in the human developing brain in association with injury, with particular focus on the preterm infant. We also explore microglia responses and mechanisms of microglia toxicity in animal models of preterm white matter injury and in vitro primary microglia cell culture experiments. PMID:24768662

  20. Active Learning by Play Dough Modeling in the Medical Profession

    ERIC Educational Resources Information Center

    Herur, Anita; Kolagi, Sanjeev; Chinagudi, Surekharani; Manjula, R.; Patil, Shailaja

    2011-01-01

    Active learning produces meaningful learning, improves attitudes toward learning, and increases knowledge and retention, but is still not fully institutionalized in the undergraduate sciences. A few studies have compared the effectiveness of PowerPoint presentations, student seminars, quizzes, and use of CD-ROMs with blackboard teaching and…

  1. Physically Active Play and Cognition: An Academic Matter?

    ERIC Educational Resources Information Center

    Sattelmair, Jacob; Ratey, John J.

    2009-01-01

    The authors discuss the growing evidence that strenuous physical activity is not only healthy for students but improves their academic performance. Based on such research, they argue that schools in the United States need to stop eliminating physical-education programs under the current political pressures to emphasize academics and instead to…

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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

  5. Active Learning in the Classroom: The Use of Group Role Plays.

    ERIC Educational Resources Information Center

    Kitzerow, Phyllis

    1990-01-01

    Describes group role-playing activities that have been used to teach about education, criminology, and sex roles. Suggests that role play helps students to absorb and retain many of the insights about the issues involved. (DB)

  6. Chemical constituents of Polygala tenuifolia roots and their inhibitory activity on lipopolysaccharide-induced nitric oxide production in BV2 microglia.

    PubMed

    Cho, Namki; Huh, Jungmoo; Yang, Heejung; Jeong, Eun Ju; Kim, Young Choong; Kim, Jinwoong; Sung, Sang Hyun

    2012-02-01

    A methanolic extract of the roots of Polygala tenuifolia (Polygalaceae) significantly attenuated nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated BV2 microglia cells. Five xanthones, 1-hydroxy-7-methoxyxanthone (1), 3,6-dihydroxy-1,2,7-trimethoxyxanthone (2), 1,3,6-trihydroxy-2,7-dimethoxyxanthone (3), 1,7-dihydroxy-2,3-dimethoxyxanthone (4) and 1,7-dihydroxy-3-methoxyxanthone (5), and five phenylpropanoids, 4-hydroxy-3-methoxypropiophenone (6), methyl 4-hydroxy-3-methoxycinnamic acid (7), 3,4,5-trimethoxycinnamic acid (8), 4-methoxycinnamic acid (9) and β-d-(3-O-sinapoyl) fructofuranosyl-α-d-(6-O-sinapoyl)glucopyranoside (10), were isolated from CHCl(3) fraction using bioactivity-guided fractionation. Among these compounds, compounds 1, 2, 4, 5 and 7 showed significant inhibitory effects on LPS-induced NO production in BV2 microglia cells at the concentration ranging from 10.0 to 100.0 μM. PMID:21740104

  7. Early modulation of pro-inflammatory microglia by minocycline loaded nanoparticles confers long lasting protection after spinal cord injury.

    PubMed

    Papa, Simonetta; Caron, Ilaria; Erba, Eugenio; Panini, Nicolò; De Paola, Massimiliano; Mariani, Alessandro; Colombo, Claudio; Ferrari, Raffaele; Pozzer, Diego; Zanier, Elisa R; Pischiutta, Francesca; Lucchetti, Jacopo; Bassi, Andrea; Valentini, Gianluca; Simonutti, Giulio; Rossi, Filippo; Moscatelli, Davide; Forloni, Gianluigi; Veglianese, Pietro

    2016-01-01

    Many efforts have been performed in order to understand the role of recruited macrophages in the progression of spinal cord injury (SCI). Different studies revealed a pleiotropic effect played by these cells associated to distinct phenotypes (M1 and M2), showing a predictable spatial and temporal distribution in the injured site after SCI. Differently, the role of activated microglia in injury progression has been poorly investigated, mainly because of the challenges to target and selectively modulate them in situ. A delivery nanovector tool (poly-ε-caprolactone-based nanoparticles) able to selectively treat/target microglia has been developed and used here to clarify the temporal and spatial involvement of the pro-inflammatory response associated to microglial cells in SCI. We show that a treatment with nanoparticles loaded with minocycline, the latter a well-known anti-inflammatory drug, when administered acutely in a SCI mouse model is able to efficiently modulate the resident microglial cells reducing the pro-inflammatory response, maintaining a pro-regenerative milieu and ameliorating the behavioral outcome up to 63 days post injury. Furthermore, by using this selective delivery tool we demonstrate a mechanistic link between early microglia activation and M1 macrophages recruitment to the injured site via CCL2 chemokine, revealing a detrimental contribution of pro-inflammatory macrophages to injury progression after SCI. PMID:26474039

  8. Parent participation plays an important part in promoting physical activity

    PubMed Central

    Lindqvist, Anna-Karin; Kostenius, Catrine; Gard, Gunvor; Rutberg, Stina

    2015-01-01

    Although physical activity (PA) is an important and modifiable determinant of health, in Sweden only 15% of boys and 10% of girls aged 15 years old achieve the recommended levels of PA 7 days per week. Adolescents’ PA levels are associated with social influence exerted by parents, friends, and teachers. The purpose of this study was to describe parents’ experiences of being a part of their adolescents’ empowerment-inspired PA intervention. A qualitative interview study was performed at a school in the northern part of Sweden. A total of 10 parents were interviewed, and the collected data were analyzed with qualitative content analysis. Three subthemes were combined into one main theme, demonstrating that parents are one important part of a successful PA intervention. The life of an adolescent has many options and demands that make it difficult to prioritize PA. Although parents felt that they were important in supporting their adolescent, a successful PA intervention must have multiple components. Moreover, the parents noted that the intervention had a positive effect upon not only their adolescents’, but also their own PA. Interventions aimed at promoting PA among adolescents should include measures to stimulate parent participation, have an empowerment approach, and preferably be school-based. PMID:26282870

  9. Cyanobacterial Microcystis aeruginosa lipopolysaccharide elicits release of superoxide anion, thromboxane B₂, cytokines, chemokines, and matrix metalloproteinase-9 by rat microglia.

    PubMed

    Mayer, Alejandro M S; Clifford, Jonathan A; Aldulescu, Monica; Frenkel, Jeffrey A; Holland, Michael A; Hall, Mary L; Glaser, Keith B; Berry, John

    2011-05-01

    Microcystis aeruginosa (M. aeruginosa) is a cosmopolitan Gram-negative cyanobacterium that may contaminate freshwater by releasing toxins, such as lipopolysaccharide (LPS) during aquatic blooms, affecting environmental and human health. The putative toxic effects of cyanobacterial LPS on brain microglia, a glial cell type that constitutes the main leukocyte-dependent source of reactive oxygen species in the central nervous system, are presently unknown. We tested the hypothesis that in vitro concentration- and time-dependent exposure to M. aeruginosa LPS strain UTCC 299 would activate rat microglia and the concomitant generation of superoxide anion (O₂⁻). After a 17-h exposure of microglia to M.aeruginosa LPS, the following concentration-dependent responses were observed: 0.1-100 ng/ml M. aeruginosa LPS enhanced O₂⁻ generation, with limited inflammatory mediator generation; 1000-10,000 ng/ml M. aeruginosa LPS caused thromboxane B₂ (TXB₂), matrix metalloproteinase-9 (MMP-9), and macrophage inflammatory protein-2 (MIP-2/CXCL2) release, concurrent with maximal O₂⁻ generation; 100,000 ng/mL M. aeruginosa LPS deactivated O₂⁻ production but maintained elevated levels of TXB₂, MMP-9, tumor necrosis factor-α (TNF-α), interleukin 1-α (IL-1α), and interleukin-6 (IL-6), macrophage inflammatory protein 1α (MIP-1α/CCL3), and MIP-2/CXCL2, with concomitant lactic dehydrogenase release. Although M. aeruginosa LPS was consistently less potent than Escherichia coli LPS, with the exception of O₂⁻, TXB₂, and MCP-1/CCL2 generation, it was more efficacious because higher levels of MMP-9, TNF-α, IL-1α, IL-6, MIP-1α/CCL3, and MIP-2/CXCL2 were produced. Our in vitro studies suggest that one or more of the inflammatory mediators released during M. aeruginosa LPS stimulation of microglia may play a critical role in the subsequent ability of microglia to generate O₂⁻. To our knowledge, this is the first experimental evidence that LPS isolated from a M

  10. Schizandrin A Inhibits Microglia-Mediated Neuroninflammation through Inhibiting TRAF6-NF-κB and Jak2-Stat3 Signaling Pathways

    PubMed Central

    Song, Fangjiao; Zeng, Kewu; Liao, Lixi; Yu, Qian; Tu, Pengfei; Wang, Xuemei

    2016-01-01

    Microglial-mediated neuroinflammation has been established as playing a vital role in pathogenesis of neurodegenerative disorders. Thus, rational regulation of microglia functions to inhibit inflammation injury may be a logical and promising approach to neurodegenerative disease therapy. The purposes of the present study were to explore the neuroprotective effects and potential molecular mechanism of Schizandrin A (Sch A), a lignin compound isolated from Schisandra chinesnesis. Our observations showed that Sch A could significantly down-regulate the increased production of nitric oxide (NO), tumor necrosis factor (TNF)-α and interleukin (IL)-6 induced by lipopolysaccharide (LPS) both in BV-2 cells and primary microglia cells. Moreover, Sch A exerted obvious neuroprotective effects against inflammatory injury in neurons when exposed to microglia-conditioned medium. Investigations of the mechanism showed the anti-inflammatory effect of Sch A involved the inhibition of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expression levels and inhibition of the LPS-induced TRAF6-IKKβ-NF-κB pathway. Furthermore, inhibition of Jak2-Stat3 pathway activation and Stat3 nuclear translocation also was observed. In conclusion, SchA can exert anti-inflammatory and neuroprotective effects by alleviating microglia-mediated neuroinflammation injury through inhibiting the TRAF6-IKKβ-NF-κB and Jak2-Stat3 signaling pathways. PMID:26919063

  11. p21-Activated Kinase 1 Plays a Critical Role in Cellular Activation by Nef

    PubMed Central

    Fackler, Oliver T.; Lu, Xiaobin; Frost, Jeffrey A.; Geyer, Matthias; Jiang, Bing; Luo, Wen; Abo, Arie; Alberts, Arthur S.; Peterlin, B. Matija

    2000-01-01

    The activation of Nef-associated kinase (NAK) by Nef from human and simian immunodeficiency viruses is critical for efficient viral replication and pathogenesis. This induction occurs via the guanine nucleotide exchange factor Vav and the small GTPases Rac1 and Cdc42. In this study, we identified NAK as p21-activated kinase 1 (PAK1). PAK1 bound to Nef in vitro and in vivo. Moreover, the induction of cytoskeletal rearrangements such as the formation of trichopodia, the activation of Jun N-terminal kinase, and the increase of viral production were blocked by an inhibitory peptide that targets the kinase activity of PAK1 (PAK1 83-149). These results identify NAK as PAK1 and emphasize the central role its kinase activity plays in cytoskeletal rearrangements and cellular signaling by Nef. PMID:10713183

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

    SciTech Connect

    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

    2013-05-15

    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.

  13. Benfotiamine Attenuates Inflammatory Response in LPS Stimulated BV-2 Microglia

    PubMed Central

    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

  14. Early morphofunctional plasticity of microglia in response to acute lipopolysaccharide.

    PubMed

    Madore, C; Joffre, C; Delpech, J C; De Smedt-Peyrusse, V; Aubert, A; Coste, L; Layé, S; Nadjar, A

    2013-11-01

    Within the central nervous system (CNS) the traditional role of microglia has been in brain infection and disease, phagocytosing debris and secreting factors to modify disease progression. This led to the concept of "resting" versus "activated" microglia. However, this is misleading because multiple phenotypic and morphological stages of microglia can influence neuronal structure and function in any condition and recent evidence extends their role to healthy brain homeostasis. The present work was thus aimed at reappraising the concept of morphofunctional activity of microglia in a context of peripheral acute immune challenge, where microglial activity is known to be modified, using the new state-of-the-art techniques available. To do so, mice were injected peripherally with lipopolysaccharide, a potent inducer of cerebral inflammation, and we assessed early cytokines production, phenotype, motility and morphology of microglial cells. Our results showed that LPS induced a widespread inflammatory response both peripherally and centrally, as revealed by the quantification of cytokines levels. We also found an alteration of microglial motility that was confirmed by in vivo studies showing an overall reduction of microglial processes length in the hippocampus of LPS-treated animals. Finally, analysis of various surface receptors expression revealed that LPS did not significantly impact microglial phenotype 2h after the injection but rather induced an increase of CD11b(+)/CD45(high) cells. These latter may be at the vasculature, at the CNS vicinity, or may have invaded the CNS. PMID:23994463

  15. Microglia in Infectious Diseases of the Central Nervous System

    PubMed Central

    Mariani, Monica M.; Kielian, Tammy

    2010-01-01

    Microglia are the resident macrophage population in the central nervous system (CNS) parenchyma and, as such, are poised to provide a first line of defense against invading pathogens. Microglia are endowed with a vast repertoire of pattern recognition receptors that include such family members as Toll-like receptors and phagocytic receptors, which collectively function to sense and eliminate microbes invading the CNS parenchyma. In addition, microglial activation elicits a broad range of pro-inflammatory cytokines and chemokines that are involved in the recruitment and subsequent activation of peripheral immune cells infiltrating the infected CNS. Studies from several laboratories have demonstrated the ability of microglia to sense and respond to a wide variety of pathogens capable of colonizing the CNS including bacterial, viral, and fungal species. This review will highlight the role of microglia in microbial recognition and the resultant antipathogen response that ensues in an attempt to clear these infections. Implications as to whether microglial activation is uniformly beneficial to the CNS or in some circumstances may exacerbate pathology will also be discussed. PMID:19728102

  16. Serum- and glucocorticoid-inducible kinases in microglia.

    PubMed

    Inoue, Koichi; Sakuma, Eisuke; Morimoto, Hiroyuki; Asai, Hayato; Koide, Yoshinori; Leng, Tiandong; Wada, Ikuo; Xiong, Zhi-Gang; Ueki, Takatoshi

    2016-09-01

    Microglia are derived from myelogenous cells and contribute to immunological and inflammatory responses in central nervous system. They play important roles not only in infectious diseases and inflammation after stroke, but also in psychiatric diseases such as schizophrenia. While recent studies suggest the significances of serum- and glucocorticoid-inducible kinases (SGKs) in other immune cells such as macrophages, T cells and dendritic cells, their role in microglia remains unknown. Here we, for the first time, report that SGK1 and SGK3 are expressed in multiple microglial cell lines. An SGK inhibitor, gsk650394, inhibits cell viability. In addition, lipopolysaccharide-induced expression of inflammatory regulators iNOS and TNFα was enhanced by gsk650394. Furthermore, translocation of NF-κB was enhanced by gsk650394. Taken together, these findings suggest that SGKs may play an important role in regulating microglial viability and inflammatory responses. PMID:27457803

  17. 'Active play may be lots of fun, but it's certainly not frivolous': the emergence of active play as a health practice in Canadian public health.

    PubMed

    Alexander, Stephanie A; Frohlich, Katherine L; Fusco, Caroline

    2014-11-01

    In the context of what has been termed a childhood obesity epidemic, public health institutions have recently begun to promote active play as a means of addressing childhood obesity, thus advancing play for health. Drawing on Foucault, this article problematises the way that children's play is being taken up as a health practice and further considers some of the effects this may have for children. Six Canadian public health websites were examined, from which 150 documents addressing children's health, physical activity, obesity, leisure activities and play were selected and coded deductively (theoretical themes) and inductively (emerging themes). Bacchi's () question-posing approach to critical discourse analysis deepened our analysis of dominant narratives. Our findings suggest that several taken-for-granted assumptions and practices underlie this discourse: (i) play is viewed as a productive activity legitimises it as a health practice; (ii) tropes of 'fun' and 'pleasure' are drawn on to promote physical activity; (iii) children are encouraged to self-govern their leisure time to promote health. We underscore the need to recognise this discourse as contingent and as only one of many ways of conceptualising children's leisure activities and their health and social lives more generally. PMID:24915830

  18. Role of iPLA2 in the regulation of Src trafficking and microglia chemotaxis

    PubMed Central

    Lee, Sang-Hyun; Schneider, Claus; Higdon, Ashlee N; Darley-Usmar, Victor M.; Chung, Chang Y.

    2011-01-01

    Microglia are immune effector cells in the CNS and their activation, migration, and proliferation play crucial roles in brain injuries and diseases. We examined the role of iPLA2 in the regulation of microglia chemotaxis toward ADP. Inhibition of iPLA2 by BEL or iPLA2 knock-down exerted a significant inhibition on PI3K activation and chemotaxis. Further examination revealed that iPLA2 knock-down abrogated Src activation which is required for PI3K activation and chemotaxis. Colocalization studies demonstrated that cSrc-GFP was retained in the endosomal recycling compartment (ERC) in iPLA2 knock-down cells, but addition of arachidonic acid (AA) could restore cSrc trafficking to the plasma membrane by allowing the formation/release of recycling endosomes associated with cSrc-GFP. Using BODIPY-AA, we showed that AA is selectively enriched in recycling endosomes. These results suggest that AA is required for the cSrc trafficking to the plasma membrane by controlling the formation/release of recycling endosomes from the ERC. PMID:21438970

  19. Development of ramified microglia from early macrophages in the zebrafish optic tectum.

    PubMed

    Svahn, Adam J; Graeber, Manuel B; Ellett, Felix; Lieschke, Graham J; Rinkwitz, Silke; Bennett, Maxwell R; Becker, Thomas S

    2013-01-01

    Microglia, the resident macrophage precursors of the brain, are necessary for the maintenance of tissue homeostasis and activated by a wide range of pathological stimuli. They have a key role in immune and inflammatory responses. Early microglia stem from primitive macrophages, however the transition from early motile forms to the ramified mature resident microglia has not been assayed in real time. In order to provide such an assay, we used zebrafish transgenic lines in which fluorescent reporter expression is driven by the promoter of macrophage expressed gene 1 (mpeg1; Ellet et al. [2011]: Blood 117(4): e49-e56,). This enabled the investigation of the development of these cells in live, intact larvae. We show that microglia develop from highly motile amoeboid cells that are engaged in phagocytosis of apoptotic cell bodies into a microglial cell type that rapidly morphs back and forth between amoeboid and ramified morphologies. These morphing microglia eventually settle into a typical mature ramified morphology. Developing microglia frequently come into contact with blood capillaries in the brain, and also frequently contact each other. Up to 10 days postfertilization, microglia were observed to undergo symmetric division. In the adult optic tectum, the microglia are highly branched, resembling mammalian microglia. In addition, the mpeg1 transgene also labeled highly branched cells in the skin overlying the optic tectum from 8-9 days postfertilization, which likely represent Langerhans cells. Thus, the development of zebrafish microglia and their cellular interactions was studied in the intact developing brain in real time and at cellular resolution. PMID:22648905

  20. Plasticity of primary microglia on micropatterned geometries and spontaneous long-distance migration in microfluidic channels

    PubMed Central

    2013-01-01

    Background Microglia possess an elevated grade of plasticity, undergoing several structural changes based on their location and state of activation. The first step towards the comprehension of microglia’s biology and functional responses to an extremely mutable extracellular milieu, consists in discriminating the morphological features acquired by cells maintained in vitro under diverse environmental conditions. Previous work described neither primary microglia grown on artificially patterned environments which impose physical cues and constraints, nor long distance migration of microglia in vitro. To this aim, the present work exploits artificial bio-mimetic microstructured substrates with pillar-shaped or line-grating geometries fabricated on poly(dimethylsiloxane) by soft lithography, in addition to microfluidic devices, and highlights some morphological/functional characteristics of microglia which were underestimated or unknown so far. Results We report that primary microglia selectively adapt to diverse microstructured substrates modifying accordingly their morphological features and behavior. On micropatterned pillar-shaped geometries, microglia appear multipolar, extend several protrusions in all directions and form distinct pseudopodia. On both micropatterned line-grating geometries and microfluidic channels, microglia extend the cytoplasm from a roundish to a stretched, flattened morphology and assume a filopodia-bearing bipolar structure. Finally, we show that in the absence of any applied chemical gradient, primary microglia spontaneously moves through microfluidic channels for a distance of up to 500 μm in approximately 12 hours, with an average speed of 0.66 μm/min. Conclusions We demonstrate an elevated grade of microglia plasticity in response to a mutable extracellular environment, thus making these cells an appealing population to be further exploited for lab on chip technologies. The development of microglia-based microstructured

  1. Influences of Technology-Related Playful Activity and Thought on Moral Development

    ERIC Educational Resources Information Center

    Bergen, Doris; Davis, Darrel

    2011-01-01

    Many early developmental theorists such as Freud, Erikson, Piaget, and Vygotsky suggested that play--which the authors of this article define as both playful activity and playful thought--had the power to influence the moral emotions, behaviors, and reasoning of children. More recent researchers have also found evidence of moral development in…

  2. PDE4B as a microglia target to reduce neuroinflammation.

    PubMed

    Pearse, Damien D; Hughes, Zoë A

    2016-10-01

    The importance of microglia in immune homeostasis within the brain is undisputed. Their role in a diversity of neurological and psychiatric diseases as well as CNS injury is the subject of much investigation. Cyclic adenosine monophosphate (AMP) is a critical regulator of microglia homeostasis; as the predominant negative modulator of cyclic AMP signaling within microglia, phosphodiesterase 4 (PDE4) represents a promising target for modulating immune function. PDE4 expression is regulated by inflammation, and in turn, PDE4 inhibition can alter microglia reactivity. As the prototypic PDE4 inhibitor, rolipram, was tested clinically in the 1980s, drug discovery and clinical development of PDE4 inhibitors have been severely hampered by tolerability issues involving nausea and emesis. The two PDE4 inhibitors approved for peripheral inflammatory disorders (roflumilast and apremilast) lack brain penetration and are dose-limited by side effects making them unsuitable for modulating microglial function. Subtype selective inhibitors targeting PDE4B are of high interest given the critical role PDE4B plays in immune function versus the association of PDE4D with nausea and emesis. The challenges and requirements for successful development of a novel brain-penetrant PDE4B inhibitor are discussed in the context of early clinical development strategies. Furthermore, the challenges of monitoring the state of microglia in vivo are highlighted, including a description of the currently available tools and their limitations. Continued drug discovery efforts to identify safe and well-tolerated, brain-penetrant PDE4 inhibitors are a reflection of the confidence in the rationale for modulation of this target to produce meaningful therapeutic benefit in a wide range of neurological conditions and injury. GLIA 2016;64:1698-1709. PMID:27038323

  3. Inflammatory signals induce the expression of tonicity-responsive enhancer binding protein (TonEBP) in microglia.

    PubMed

    Jeong, Ga Ram; Im, Sun-Kyoung; Bae, Yun-Hee; Park, Eun Su; Jin, Byung Kwan; Kwon, Hyug Moo; Lee, Beom-Joon; Bu, Youngmin; Hur, Eun-Mi; Lee, Byoung Dae

    2016-06-15

    Tonicity-responsive enhancer (TonE) binding protein (TonEBP) is known as an osmosensitive transcription factor that regulates cellular homeostasis during states of hypo- and hypertonic stress. In addition to its role in osmoadaptation, growing lines of evidence suggest that TonEBP might have tonicity-independent functions. In particular, a number of studies suggest that inflammatory stimuli induce the expression and activation of TonEBP in peripheral immune cells. However, whether TonEBP is expressed in microglia, resident immune cells of the central nervous system, is unknown. Here we show that inflammatory signals induce the expression of TonEBP in microglia both in vitro and in vitro. In cultured primary microglia, treatment with lipopolysaccharide (LPS), interferon-γ, and interleukin 4 increased the expression of TonEBP. Moreover, we found that stereotaxic injection of LPS into the substantia nigra region of rat brain increased TonEBP expression in OX-42-positive cells. Furthermore, expression of TonEBP was induced in OX-42-positive cells in a rat model of transient middle cerebral artery occlusion. Together these results show that the expression of TonEBP is regulated by inflammatory signals in mammalian brain, suggesting that TonEBP might play a part during neuroinflammation. PMID:27235345

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

    PubMed

    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'. PMID:25549562

  5. Effects of dexmedetomidine on P2X4Rs, p38-MAPK and BDNF in spinal microglia in rats with spared nerve injury.

    PubMed

    Zhou, Tian-tian; Wu, Jing-ru; Chen, Zi-yang; Liu, Zhen-xiu; Miao, Bei

    2014-06-01

    Microglia in the spinal cord is evidenced to play a crucial role in neuropathic pain. Spinal P2X4 receptors (P2X4Rs), which are mainly expressed in microglia, have been investigated for their roles in neuropathic pain. Dexmedetomidine (DEX), a highly selective agonist of α2-adrenergic receptors, is clinically applied to sedation and analgesia. Despite the proposed mechanisms underlying DEX-induced analgesia, the possible interactions between DEX and P2X4Rs at a molecular level have not been elucidated. We designated the spared nerve injury (SNI) to establish the neuropathic pain model. Mechanical paw withdrawal threshold (MWT) was measured to evaluate the sensitivity of neuropathic pain in rats. MWT was significantly decreased in SNI rats versus control rats. Expressions of spinal P2X4Rs, phosphorylated p38-mitogen-activated protein kinase (p-p38-MAPK) and brain-derived neurotrophic factor (BDNF) were upregulated in SNI rats. Immunofluorescence assay indicated higher densities of microglia and P2X4Rs, which appeared yellow in colour, suggesting they were co-labelled. Intraperitoneal injections of DEX 40μg/kg for 14 consecutive days markedly reversed the SNI-induced decline of MWT; the activation of microglia was markedly inhibited; in addition, the protein expressions of P2X4Rs, p-p38-MAPK and BDNF were significantly downregulated. Thus, DEX could attenuate the neuropathic pain in SNI rats, of which the mechanism might be related to the down-expressed P2X4Rs, p-p38 and BDNF in microglia of spinal dorsal horn. PMID:24792496

  6. Energy expended playing video console games: an opportunity to increase children's physical activity?

    PubMed

    Maddison, Ralph; Mhurchu, Cliona Ni; Jull, Andrew; Jiang, Yannan; Prapavessis, Harry; Rodgers, Anthony

    2007-08-01

    This study sought to quantify the energy expenditure and physical activity associated with playing the "new generation" active and nonactive console-based video games in 21 children ages 10-14 years. Energy expenditure (kcal) derived from oxygen consumption (VO2) was continuously assessed while children played nonactive and active console video games. Physical activity was assessed continuously using the Actigraph accelerometer. Significant (p < .001) increases from baseline were found for energy expenditure (129-400%), heart rate (43-84%), and activity counts (122-1288 versus 0-23) when playing the active console video games. Playing active console video games over short periods of time is similar in intensity to light to moderate traditional physical activities such as walking, skipping, and jogging. PMID:18019591

  7. Integration of Structured Expressive Activities within a Humanistic Group Play Therapy Format for Preadolescents

    ERIC Educational Resources Information Center

    Bratton, Sue C.; Ceballos, Peggy L.; Ferebee, Kelly Webb

    2009-01-01

    The integration of expressive activities in play groups with preadolescents encourages them to reach more deeply into their own resources, enabling them to handle future challenges more effectively. Developmental and therapeutic rationale, along with research support, is given for the integration of creative activities into a humanistic play group…

  8. Comparing Role-Playing Activities in Second Life and Face-to-Face Environments

    ERIC Educational Resources Information Center

    Gao, Fei; Noh, Jeongmin J.; Koehler, Matthew J.

    2009-01-01

    This study compared student performances in role-playing activities in both a face-to-face (FTF) environment and a virtual 3D environment, Second Life (SL). We found that students produced a similar amount of communication in the two environments, but the communication styles were different. In SL role-playing activities, students took more…

  9. Teachers' Beliefs Related to Activity Play in the Preschool Setting: A Phenomenological Investigation

    ERIC Educational Resources Information Center

    Pisha, Lorelei Emma

    2012-01-01

    The purpose of the present study was to investigate how early childhood teachers working in Head Start programs made meaning of preschool-age children's physical activity play by exploring their personal childhood and professional experiences with physical activity play. The study was conducted to contribute research-based recommendations for…

  10. Activation of mitochondrial transient receptor potential vanilloid 1 channel contributes to microglial migration.

    PubMed

    Miyake, Takahito; Shirakawa, Hisashi; Nakagawa, Takayuki; Kaneko, Shuji

    2015-10-01

    Microglia, the resident immune cells in the brain, survey the environment of the healthy brain. Microglial migration is essential for many physiological and pathophysiological processes. Although microglia express some members of the transient receptor potential (TRP) channel family, there is little knowledge regarding the physiological roles of TRP channels in microglia. Here, we explored the role of TRP vanilloid 1 (TRPV1), a channel opened by capsaicin, heat, protons, and endovanilloids, in microglia. We found that application of capsaicin induced concentration-dependent migration in microglia derived from wild-type mice but not in those derived from TRPV1 knockout (TRPV1-KO) mice. Capsaicin-induced microglial migration was significantly inhibited by co-application of the TRPV1 blocker SB366791 and the Ca(2+) chelator BAPTA-AM. Using RT-PCR and immunocytochemistry, we validated that TRPV1 was expressed in microglia. Electrophysiological recording, intracellular Ca(2+) imaging, and immunocytochemistry indicated that TRPV1 was localized primarily in intracellular organelles. Treatment with capsaicin induced an increase in intramitochondrial Ca(2+) concentrations and mitochondrial depolarization. Furthermore, microglia derived from TRPV1-KO mice showed delayed Ca(2+) efflux compared with microglia derived from wild-type mice. Capsaicin-induced microglial migration was inhibited by membrane-permeable antioxidants and MAPK inhibitors, suggesting that mitochondrial TRPV1 activation induced Ca(2+) -dependent production of ROS followed by MAPK activation, which correlated with an augmented migration of microglia. Moreover, a mixture of three endovanilloids augmented microglial migration via TRPV1 activation. Together, these results indicate that mitochondrial TRPV1 plays an important role in inducing microglial migration. Activation of TRPV1 triggers an increase in intramitochondrial Ca(2+) concentration and following depolarization of mitochondria, which results in mt

  11. Sodium channels in astroglia and microglia.

    PubMed

    Pappalardo, Laura W; Black, Joel A; Waxman, Stephen G

    2016-10-01

    Voltage-gated sodium channels are required for electrogenesis in excitable cells. Their activation, triggered by membrane depolarization, generates transient sodium currents that initiate action potentials in neurons, cardiac, and skeletal muscle cells. Cells that have not traditionally been considered to be excitable (nonexcitable cells), including glial cells, also express sodium channels in physiological conditions as well as in pathological conditions. These channels contribute to multiple functional roles that are seemingly unrelated to the generation of action potentials. Here, we discuss the dynamics of sodium channel expression in astrocytes and microglia, and review evidence for noncanonical roles in effector functions of these cells including phagocytosis, migration, proliferation, ionic homeostasis, and secretion of chemokines/cytokines. We also examine possible mechanisms by which sodium channels contribute to the activity of glial cells, with an eye toward therapeutic implications for central nervous system disease. GLIA 2016;64:1628-1645. PMID:26919466

  12. Physical Activity Play and Preschool Children's Peer Acceptance: Distinctions between Rough-and-Tumble and Exercise Play

    ERIC Educational Resources Information Center

    Lindsey, Eric W.

    2014-01-01

    Research Findings: Two forms of exercise play (toy mediated and non-mediated) and 2 forms of rough-and-tumble (R&T) play (chase and fighting) were examined in relation to preschoolers' peer competence. A total of 148 preschoolers (78 boys, 89 Euro-Americans) were observed during free play at their university-sponsored child care center.…

  13. Microglia of Prefrontal White Matter in Suicide

    PubMed Central

    Schnieder, Tatiana P.; Trencevska, Iskra; Rosoklija, Gorazd; Stankov, Aleksandr; Mann, J. John; Smiley, John; Dwork, Andrew J.

    2014-01-01

    Immune functions in the brain are associated with psychiatric illness and with temporary alteration of mental state. Microglia, the principal brain immunological cells, respond to changes in the internal brain milieu through a sequence of activated states, each with characteristic function and morphology. To assess a possible association of frontal white matter pathology with suicide, autopsy brain tissue samples from 11 suicide and 25 non-suicide subjects were stained for ionized calcium-binding adapter molecule 1 (Iba-1), CD68, and myelin. Groups were matched by age, sex, and psychiatric diagnosis. We classified Iba-1-immunoreactive cells on the basis of shape, immunoreactivity for CD68, and association with blood vessels to obtain stereologic estimates of densities of resting microglia, activated phagocytes, and perivascular cells. We found no effect of psychiatric diagnosis but 2 statistically significant effects of suicide: 1) the dorsal-ventral difference in activated microglial density was reversed such that with suicide, the density was greater in ventral than in dorsal prefrontal white matter, whereas in the absence of suicide, the opposite was true; and 2) with suicide there was a greater density of Iba-1-immunoreactive cells within or in contact with blood vessel walls in dorsal prefrontal white matter. These observations could reflect a mechanism for the stress/diathesis (state/trait) model of suicide whereby an acute stress activates a reactive process in the brain, either directly or by compromising the blood-brain barrier, and creates a suicidal state in an individual at risk. They also indicate the theoretical potential of imaging studies in live, vulnerable individuals for the assessment of suicide risk. Further studies are needed to investigate specific phenotypes of perivascular cells and blood-brain barrier changes associated with suicide. PMID:25101704

  14. Phagocytosis of neuronal debris by microglia is associated with neuronal damage in multiple sclerosis.

    PubMed

    Huizinga, Ruth; van der Star, Baukje J; Kipp, Markus; Jong, Rosa; Gerritsen, Wouter; Clarner, Tim; Puentes, Fabiola; Dijkstra, Christine D; van der Valk, Paul; Amor, Sandra

    2012-03-01

    Neuroaxonal degeneration is a pathological hallmark of multiple sclerosis (MS) contributing to irreversible neurological disability. Pathological mechanisms leading to axonal damage include autoimmunity to neuronal antigens. In actively demyelinating lesions, myelin is phagocytosed by microglia and blood-borne macrophages, whereas the fate of degenerating or damaged axons is unclear. Phagocytosis is essential for clearing neuronal debris to allow repair and regeneration. However, phagocytosis may lead to antigen presentation and autoimmunity, as has been described for neuroaxonal antigens. Despite this notion, it is unknown whether phagocytosis of neuronal antigens occurs in MS. Here, we show using novel, well-characterized antibodies to axonal antigens, that axonal damage is associated with HLA-DR expressing microglia/macrophages engulfing axonal bulbs, indicative of axonal damage. Neuronal proteins were frequently observed inside HLA-DR(+) cells in areas of axonal damage. In vitro, phagocytosis of neurofilament light (NF-L), present in white and gray matter, was observed in human microglia. The number of NF-L or myelin basic protein (MBP) positive cells was quantified using the mouse macrophage cell line J774.2. Intracellular colocalization of NF-L with the lysosomal membrane protein LAMP1 was observed using confocal microscopy confirming that NF-L is taken up and degraded by the cell. In vivo, NF-L and MBP was observed in cerebrospinal fluid cells from patients with MS, suggesting neuronal debris is drained by this route after axonal damage. In summary, neuroaxonal debris is engulfed, phagocytosed, and degraded by HLA-DR(+) cells. Although uptake is essential for clearing neuronal debris, phagocytic cells could also play a role in augmenting autoimmunity to neuronal antigens. PMID:22161990

  15. Inefficient clearance of myelin debris by microglia impairs remyelinating processes

    PubMed Central

    Lampron, Antoine; Larochelle, Antoine; Laflamme, Nathalie; Préfontaine, Paul; Plante, Marie-Michèle; Sánchez, Maria Gabriela; Yong, V. Wee; Stys, Peter K.; Tremblay, Marie-Ève

    2015-01-01

    An imbalance between remyelinating and demyelinating rates underlies degenerative processes in demyelinating diseases such as multiple sclerosis. An optimal therapeutic strategy would be to stimulate remyelination while limiting demyelination. Although accumulation of myelin debris impairs remyelination, the mechanisms regulating the clearance of such debris by mononuclear phagocytic cells are poorly understood. We demonstrate that after cuprizone intoxication, CCR2-dependent infiltration of mouse bone marrow–derived cells is abundant in demyelinating areas, but that these cells do not impact demyelination. However, in CX3CR1-deficient mice, the clearance of myelin debris by microglia was blocked greatly, affecting the integrity of the axon and myelin sheaths and thus preventing proper remyelination. These results highlight the crucial role played by CX3CR1 in myelin removal and show that there can be no efficient remyelination after a primary demyelinating insult if myelin clearance by microglia is impaired. PMID:25779633

  16. S100B protein stimulates microglia migration via RAGE-dependent up-regulation of chemokine expression and release.

    PubMed

    Bianchi, Roberta; Kastrisianaki, Eirini; Giambanco, Ileana; Donato, Rosario

    2011-03-01

    The Ca(2+)-binding protein of the EF-hand type, S100B, is abundantly expressed in and secreted by astrocytes, and release of S100B from damaged astrocytes occurs during the course of acute and chronic brain disorders. Thus, the concept has emerged that S100B might act an unconventional cytokine or a damage-associated molecular pattern protein playing a role in the pathophysiology of neurodegenerative disorders and inflammatory brain diseases. S100B proinflammatory effects require relatively high concentrations of the protein, whereas at physiological concentrations S100B exerts trophic effects on neurons. Most if not all of the extracellular (trophic and toxic) effects of S100B in the brain are mediated by the engagement of RAGE (receptor for advanced glycation end products). We show here that high S100B stimulates murine microglia migration in Boyden chambers via RAGE-dependent activation of Src kinase, Ras, PI3K, MEK/ERK1/2, RhoA/ROCK, Rac1/JNK/AP-1, Rac1/NF-κB, and, to a lesser extent, p38 MAPK. Recruitment of the adaptor protein, diaphanous-1, a member of the formin protein family, is also required for S100B/RAGE-induced migration of microglia. The S100B/RAGE-dependent activation of diaphanous-1/Rac1/JNK/AP-1, Ras/Rac1/NF-κB and Src/Ras/PI3K/RhoA/diaphanous-1 results in the up-regulation of expression of the chemokines, CCL3, CCL5, and CXCL12, whose release and activity are required for S100B to stimulate microglia migration. Lastly, RAGE engagement by S100B in microglia results in up-regulation of the chemokine receptors, CCR1 and CCR5. These results suggests that S100B might participate in the pathophysiology of brain inflammatory disorders via RAGE-dependent regulation of several inflammation-related events including activation and migration of microglia. PMID:21209080

  17. Analysis of upper arm muscle activation using surface electromyography signals during drum playing.

    PubMed

    Chong, Hyun Ju; Kwon, Chun-Ki; Kang, Hyun-Joo; Kim, Soo Ji

    2016-06-01

    This study measured surface electromyography of the biceps brachii and triceps brachii during repeated drum playing with and without a drumstick to better understand activation of the upper arm muscles and inform the use of instrument playing for motor rehabilitation. A total of 40 healthy college students participated in this study. All participants were asked to strike a drum with their hand and with a drumstick at three different levels of stroke: soft, medium, and strong. The stroke order was randomly assigned to participants. A sound level meter was used to record the intensity of the drum playing. Surface electromyography signals were recorded at every hit during drum playing both with and without the drumstick in each of the three stroke conditions. The results demonstrated that the highest muscle activation was observed in both biceps brachii and triceps brachii with strong drum playing with and without the drumstick. A two-way repeated measures analysis of variance showed that there was a significant main effect for stroke intensity in muscle activation and produced sound level. While higher activation of the triceps brachii was observed for drum playing without a drumstick, no significant differences were found between the biceps brachii and sound level. This study demonstrated via surface electromyography data that greater muscle activation of the biceps brachii and triceps brachii does not occur with the use of drumsticks in drum playing. With the drum sound controlled, drum playing by hand can be an effective therapeutic intervention for the upper arm muscles. PMID:27419114

  18. Analysis of upper arm muscle activation using surface electromyography signals during drum playing

    PubMed Central

    Chong, Hyun Ju; Kwon, Chun-Ki; Kang, Hyun-Joo; Kim, Soo Ji

    2016-01-01

    This study measured surface electromyography of the biceps brachii and triceps brachii during repeated drum playing with and without a drumstick to better understand activation of the upper arm muscles and inform the use of instrument playing for motor rehabilitation. A total of 40 healthy college students participated in this study. All participants were asked to strike a drum with their hand and with a drumstick at three different levels of stroke: soft, medium, and strong. The stroke order was randomly assigned to participants. A sound level meter was used to record the intensity of the drum playing. Surface electromyography signals were recorded at every hit during drum playing both with and without the drumstick in each of the three stroke conditions. The results demonstrated that the highest muscle activation was observed in both biceps brachii and triceps brachii with strong drum playing with and without the drumstick. A two-way repeated measures analysis of variance showed that there was a significant main effect for stroke intensity in muscle activation and produced sound level. While higher activation of the triceps brachii was observed for drum playing without a drumstick, no significant differences were found between the biceps brachii and sound level. This study demonstrated via surface electromyography data that greater muscle activation of the biceps brachii and triceps brachii does not occur with the use of drumsticks in drum playing. With the drum sound controlled, drum playing by hand can be an effective therapeutic intervention for the upper arm muscles. PMID:27419114

  19. Anthocyanin effects on microglia M1/M2 phenotype: Consequence on neuronal fractalkine expression.

    PubMed

    Meireles, Manuela; Marques, Cláudia; Norberto, Sónia; Santos, Paulo; Fernandes, Iva; Mateus, Nuno; Faria, Ana; Calhau, Conceição

    2016-05-15

    Microglia mediate multiple aspects of neuroinflammation, including cytotoxicity, repair, regeneration, and immunosuppression due to their ability to acquire diverse activation states, or phenotypes. Modulation of microglial phenotype or microglia-neuron crosstalk can be an appealing neurotherapeutic strategy. Anthocyanins are a class of flavonoids found e.g., in berries that has been attracting interest due to its neuroprotective potential. However, there are no data clarifying the impact of anthocyanins on microglial phenotype or on microglia-neuron crosstalk (CX3CR1/CX3CL1). N9 microglia cell line was treated with 1μM cyanidin (Cy), cyanidin-3-glucose (Cy3glc) and a methylated form of cyanidin-3-glucose (Met-Cy3glc) in basal conditions and with LPS/IL-4 stimulation. SH-SY5Y cell line was treated with the conditioned medium of microglia and with the anthocyanins alone. At basal conditions, microglia treatment with anthocyanins for 24h induced a less pro-inflammatory profile. Decreased TNF-α mRNA expression was induced either by Cy and Met-Cy3glc. LPS markedly increase IL-6 mRNA expression, which was lowered by Cy3glc. IL-1β LPS-induced expression was reverted by Cy. Cy increased CX3CL1 mRNA expression in SH-SY5Y comparing either with control or LPS. Anthocyanins and metabolites were not able to shift microglia to an M2 strict phenotype however they did interact with microglia biology. There was an attenuation of M1 phenotype and increase of neuronal expression of CX3CL1 mRNA. Understanding how flavonoids modulate microglia-neuron crosstalk can open new directions for future nutritional interventions. PMID:26965567

  20. In Situ Dividing and Phagocytosing Retinal Microglia Express Nestin, Vimentin, and NG2 In Vivo

    PubMed Central

    Wohl, Stefanie G.; Schmeer, Christian W.; Friese, Thomas; Witte, Otto W.; Isenmann, Stefan

    2011-01-01

    Background Following injury, microglia become activated with subsets expressing nestin as well as other neural markers. Moreover, cerebral microglia can give rise to neurons in vitro. In a previous study, we analysed the proliferation potential and nestin re-expression of retinal macroglial cells such as astrocytes and Müller cells after optic nerve (ON) lesion. However, we were unable to identify the majority of proliferative nestin+ cells. Thus, the present study evaluates expression of nestin and other neural markers in quiescent and proliferating microglia in naïve retina and following ON transection in adult rats in vivo. Methodology/Principal Findings For analysis of cell proliferation and cells fates, rats received BrdU injections. Microglia in retinal sections or isolated cells were characterized using immunofluorescence labeling with markers for microglia (e.g., Iba1, CD11b), cell proliferation, and neural cells (e.g., nestin, vimentin, NG2, GFAP, Doublecortin etc.). Cellular analyses were performed using confocal laser scanning microscopy. In the naïve adult rat retina, about 60% of resting ramified microglia expressed nestin. After ON transection, numbers of nestin+ microglia peaked to a maximum at 7 days, primarily due to in situ cell proliferation of exclusively nestin+ microglia. After 8 weeks, microglia numbers re-attained control levels, but 20% were still BrdU+ and nestin+, although no further local cell proliferation occurred. In addition, nestin+ microglia co-expressed vimentin and NG2, but not GFAP or neuronal markers. Fourteen days after injury and following retrograde labeling of retinal ganglion cells (RGCs) with Fluorogold (FG), nestin+NG2+ microglia were positive for the dye indicating an active involvement of a proliferating cell population in phagocytosing apoptotic retinal neurons. Conclusions/Significance The current study provides evidence that in adult rat retina, a specific resident population of microglia expresses proteins of

  1. Microglia are less pro-inflammatory than myeloid infiltrates in the hippocampus of mice exposed to status epilepticus.

    PubMed

    Vinet, Jonathan; Vainchtein, Ilia D; Spano, Carlotta; Giordano, Carmela; Bordini, Domenico; Curia, Giulia; Dominici, Massimo; Boddeke, Hendrikus W G M; Eggen, Bart J L; Biagini, Giuseppe

    2016-08-01

    Activated microglia, astrogliosis, expression of pro-inflammatory cytokines, blood brain barrier (BBB) leakage and peripheral immune cell infiltration are features of mesial temporal lobe epilepsy. Numerous studies correlated the expression of pro-inflammatory cytokines with the activated morphology of microglia, attributing them a pro-epileptogenic role. However, microglia and myeloid cells such as macrophages have always been difficult to distinguish due to an overlap in expressed cell surface molecules. Thus, the detrimental role in epilepsy that is attributed to microglia might be shared with myeloid infiltrates. Here, we used a FACS-based approach to discriminate between microglia and myeloid infiltrates isolated from the hippocampus 24 h and 96 h after status epilepticus (SE) in pilocarpine-treated CD1 mice. We observed that microglia do not express MHCII whereas myeloid infiltrates express high levels of MHCII and CD40 96 h after SE. This antigen-presenting cell phenotype correlated with the presence of CD4(pos) T cells. Moreover, microglia only expressed TNFα 24 h after SE while myeloid infiltrates expressed high levels of IL-1β and TNFα. Immunofluorescence showed that astrocytes but not microglia expressed IL-1β. Myeloid infiltrates also expressed matrix metalloproteinase (MMP)-9 and 12 while microglia only expressed MMP-12, suggesting the involvement of both cell types in the BBB leakage that follows SE. Finally, both cell types expressed the phagocytosis receptor Axl, pointing to phagocytosis of apoptotic cells as one of the main functions of microglia. Our data suggests that, during early epileptogenesis, microglia from the hippocampus remain rather immune supressed whereas myeloid infiltrates display a strong inflammatory profile. GLIA 2016 GLIA 2016;64:1350-1362. PMID:27246930

  2. Cellular activation in limbic brain systems during social play behaviour in rats

    PubMed Central

    van Kerkhof, Linda W.M.; Trezza, Viviana; Mulder, Tessa; Gao, Ping; Voorn, Pieter; Vanderschuren, Louk J.M.J.

    2013-01-01

    Positive social interactions during the juvenile and adolescent phases of life are essential for proper social and cognitive development in mammals, including humans. During this developmental period, there is a marked increase in peer-peer interactions, signified by the abundance of social play behaviour. Despite its importance for behavioural development, our knowledge of the neural underpinnings of social play behaviour is limited. Therefore, the purpose of this study was to map the neural circuits involved in social play behaviour in rats. This was achieved by examining cellular activity after social play using the immediate early gene c-fos as a marker. After a session of social play behaviour, pronounced increases in c-fos expression were observed in the medial prefrontal cortex, medial and ventral orbitofrontal cortex, dorsal striatum, nucleus accumbens core and shell, lateral amygdala, several thalamic nuclei, dorsal raphe and the pedunculopontine tegmental nucleus. Importantly, the cellular activity patterns after social play were topographically organised in this network, as indicated by play-specific correlations in c-fos activity between regions with known direct connections. These correlations suggest involvement in social play behaviour of the projections from the medial prefrontal cortex to the striatum, and of amygdala and monoaminergic inputs to frontal cortex and striatum. The analyses presented here outline a topographically organised neural network implicated in processes such as reward, motivation and cognitive control over behaviour, which mediates social play behaviour in rats. PMID:23670540

  3. Motivation within Role-Playing as a Means to Intensify College Students' Educational Activity

    ERIC Educational Resources Information Center

    Burenkova, Olga Mikhailovna; Arkhipova, Irina Vladimirovna; Semenov, Sergei Aleksandrovich; Samarenkina, Saniya Zakirzyanovna

    2015-01-01

    This article covers college students' educational activity issues while studying a foreign language; analyzes special aspects of motivation introduction, their specific features. It also defines role and structure of role-playing. The authors come to the conclusion that introduction of role-playing in an educational process will bring it closer to…

  4. Using Activity Theory to Understand Intergenerational Play: The Case of Family Quest

    ERIC Educational Resources Information Center

    Siyahhan, Sinem; Barab, Sasha A.; Downton, Michael P.

    2010-01-01

    We implemented a five-week family program called "Family Quest" where parents and children ages 9 to 13 played Quest Atlantis, a multiuser 3D educational computer game, at a local after-school club for 90-minute sessions. We used activity theory as a conceptual and an analytical framework to study the nature of intergenerational play, the…

  5. Enhanced immune response to MMP3 stimulation in microglia expressing mutant huntingtin.

    PubMed

    Connolly, C; Magnusson-Lind, A; Lu, G; Wagner, P K; Southwell, A L; Hayden, M R; Björkqvist, M; Leavitt, B R

    2016-06-14

    Huntington's Disease (HD) is an inherited neurodegenerative disease caused by a polyglutamine expansion in the huntingtin protein. The YAC128 mouse model of HD expresses the full-length human huntingtin protein with 128 CAG repeats and replicates the phenotype and neurodegeneration that occur in HD. Several studies have implicated a role for neuroinflammation in HD pathogenesis. Studies on presymptomatic HD patients have illustrated microgliosis (activated microglia) in brain regions affected in HD. Mutant huntingtin expressing isolated primary monocytes (human HD patients) and primary macrophages (YAC128) are overactive in response to lipopolysaccharide (LPS) stimulation. In this study we demonstrate that cultured primary microglia (the resident immune cells of the brain cells) from YAC128 mice differentially express a wide number of cytokines compared to wildtype microglia cultures in response to LPS. Furthermore, this study outlines a direct interaction between mutant huntingtin and cytokine secretion in HD microglia. Increased cytokine release in YAC128 microglia can be blocked by cannabinoid activation or by mutant huntingtin knockdown with anti-sense oligonucleotide treatment. Matrix metalloprotease 3 (MMP3), an endogenous neuronal activator of microglia, also induces increased cytokine release from YAC128 microglia compared to wildtype microglia. We found elevated MMP levels in HD CSF, and MMP levels correlate with disease severity in HD. These data support a novel role for MMPs and microglial activation in HD pathogenesis. With an improved understanding of the specific cellular processes involved in HD neuroinflammation, novel therapeutic agents targeting these processes can be developed and hold great promise in the treatment of HD. PMID:27033979

  6. kappa opioid receptors in human microglia downregulate human immunodeficiency virus 1 expression.

    PubMed Central

    Chao, C C; Gekker, G; Hu, S; Sheng, W S; Shark, K B; Bu, D F; Archer, S; Bidlack, J M; Peterson, P K

    1996-01-01

    Microglial cells, the resident macrophages of the brain, play an important role in the neuropathogenesis of human immunodeficiency virus type 1 (HIV-1), and recent studies suggest that opioid peptides regulate the function of macrophages from somatic tissues. We report herein the presence of kappa opioid receptors (KORs) in human fetal microglia and inhibition of HIV-1 expression in acutely infected microglial cell cultures treated with KOR ligands. Using reverse transcriptase-polymerase chain reaction and sequencing analyses, we found that mRNA for the KOR was constitutively expressed in microglia and determined that the nucleotide sequence of the open reading frame was identical to that of the human brain KOR gene. The expression of KOR in microglial cells was confirmed by membrane binding of [3H]U69,593, a kappa-selective ligand, and by indirect immunofluorescence. Treatment of microglial cell cultures with U50,488 or U69,593 resulted in a dose-dependent inhibition of expression of the monocytotropic HIV-1 SF162 strain. This antiviral effect of the kappa ligands was blocked by the specific KOR antagonist, nor-binaltrophimine. These findings suggest that kappa opioid agonists have immunomodulatory activity in the brain, and that these compounds could have potential in the treatment of HIV-1-associated encephalopathy. Images Fig. 2 Fig. 4 PMID:8755601

  7. Prostaglandin E2 Reverses Aberrant Production of an Inflammatory Chemokine by Microglia from Sandhoff Disease Model Mice through the cAMP-PKA Pathway

    PubMed Central

    Kawashita, Eri; Tsuji, Daisuke; Toyoshima, Masahiro; Kanno, Yosuke; Matsuno, Hiroyuki; Itoh, Kohji

    2011-01-01

    Background Sandhoff disease (SD) is a neurodegenerative lysosomal β-hexosaminidase (Hex) deficiency involving excessive accumulation of undegraded substrates, including terminal GlcNAc-oligosaccharides and GM2 ganglioside. Microglia-mediated neuroinflammation contributes to the pathogenesis and progression of SD. Our previous study demonstrated that MIP-1α, a putative pathogenic factor for SD, is up-regulated in microglial cells derived from SD model mice (SD-Mg) through activation of Akt and JNK. Methodology/Principal Findings In this study, we first demonstrated that prostaglandin E2 (PGE2), which is one of the lipid mediators derived from arachidonic acid and is known to suppress activation of microglia, reduced the aberrant MIP-1α production by SD-Mg to the same level as by WT-Mg. PGE2 also attenuated the activation of Akt and JNK. The inhibition of MIP-1α production and the activation of Akt and JNK occurred through the EP2 and 4/cAMP/PKA signaling pathway in the murine microglia derived from SD model mice. Conclusions/Significance We propose that PGE2 plays a role as a negative regulator of MIP-1α production in the pathogenesis of SD, and that PGE2-EP2 and 4/cAMP/PKA signaling could be a target pathway for therapy for SD. PMID:21298000

  8. Creative Play Activities for Children with Disabilities: A Resource Book for Teachers and Parents. Second Edition.

    ERIC Educational Resources Information Center

    Morris, Lisa Rappaport; Schulz, Linda

    This book provides 250 games and activities designed to help infants to 8-year-olds with all types of disabilities grow through play. Many activities come with special adaptations for children with physical, visual, hearing, emotional, and cognitive impairments. Each chapter focuses on a particular "world" or activity theme. Topics of individual…

  9. Role of dietary phenols in mitigating microglia-mediated neuroinflammation.

    PubMed

    Rangarajan, Parakalan; Karthikeyan, Aparna; Dheen, S T

    2016-09-01

    Chronic neuroinflammation is a pathological feature of a number of central nervous system (CNS) diseases and is mediated by sustained activation of microglial cells, the innate immune cells of the CNS. Studies have mainly focused on identifying the molecular and epigenetic mechanisms of microglial activation. This is crucial in designing therapeutic strategies for neuropathologies in which prolonged microglial activation is known to exacerbate disease condition. In recent years, increasing evidence show that naturally occurring compounds present in regular diet could function as "nutraceuticals," arresting microglial activation, and thus conferring neuroprotection. This review summarizes our understanding of the role of dietary phenolic nutraceuticals in mitigating microglia-mediated neuroinflammation. Studies show that these natural phenols inhibit key signaling pathways in activated microglia such as the NFκB, MAPK and JAK-STAT that trigger microglia-mediated inflammation in various neuropathological conditions such as injury, infection, stroke, autism and neurodegenerative diseases, i.e., Alzheimer's disease and Parkinson's disease. The anti-inflammatory and antioxidant effect exerted by these natural phenols have shown considerable success in improving disease condition in animal models of neuropathologies, and thus seem to be suitable candidates for developing therapeutic strategies. PMID:27465151

  10. The Benefits and Detriments of Macrophages/Microglia in Models of Multiple Sclerosis

    PubMed Central

    Rawji, Khalil S.; Yong, V. Wee

    2013-01-01

    The central nervous system (CNS) is immune privileged with access to leukocytes being limited. In several neurological diseases, however, infiltration of immune cells from the periphery into the CNS is largely observed and accounts for the increased representation of macrophages within the CNS. In addition to extensive leukocyte infiltration, the activation of microglia is frequently observed. The functions of activated macrophages/microglia within the CNS are complex. In three animal models of multiple sclerosis (MS), namely, experimental autoimmune encephalomyelitis (EAE) and cuprizone- and lysolecithin-induced demyelination, there have been many reported detrimental roles associated with the involvement of macrophages and microglia. Such detriments include toxicity to neurons and oligodendrocyte precursor cells, release of proteases, release of inflammatory cytokines and free radicals, and recruitment and reactivation of T lymphocytes in the CNS. Many studies, however, have also reported beneficial roles of macrophages/microglia, including axon regenerative roles, assistance in promoting remyelination, clearance of inhibitory myelin debris, and the release of neurotrophic factors. This review will discuss the evidence supporting the detrimental and beneficial aspects of macrophages/microglia in models of MS, provide a discussion of the mechanisms underlying the dichotomous roles, and describe a few therapies in clinical use in MS that impinge on the activity of macrophages/microglia. PMID:23840244

  11. Is traumatic axonal injury (AI) associated with an early microglial activation? Application of a double-labeling technique for simultaneous detection of microglia and AI.

    PubMed

    Oehmichen, M; Theuerkauf, I; Meissner, C

    1999-05-01

    The aim of the present study was to determine whether axonal injury (AI) induces a microglial reaction within 15 days after brain trauma. In 40 selected cases of confirmed AI, the topographical relation of AI and microglial reaction was assessed using an immunohistochemical double-labeling technique for simultaneous demonstration of AI using beta-amyloid precursor protein (beta-APP) antibody and of microglia using CD68 antibody. Although traumatic injury was usually followed by a moderate early diffuse rise in the number of CD68-reactive cells in the white matter, increases in macrophages in areas of AI accumulation were only sporadic and did not occur until after 4 days. At survival intervals of 5-15 days a moderate microglial reaction in regions of beta-APP-positive injured axons was detected, at maximum, in half of the case material. During this interval AI-associated satellitosis-like clusters or stars described by other authors after a survival time of more than 7 weeks were an isolated phenomenon. The prolonged microglial reaction as well as the reduction of beta-APP-positive AI during longer survival periods supports the hypothesis that AI is not primarily chemotactically attractive and that the damage to a portion of beta-APPstained axons may be partly reversible. Most cases clearly require a prolonged interval of more than 15 days before initiation of the final scavenger reaction. For forensic purposes the increase in the number of microglial cells within the region of AI accumulation after a survival time of more than 5 days and the multiple and distinct demonstration of star-like microglial reactions within the white matter after survival times exceeding 7 weeks may provide valuable postmortem information on the timing of a traumatic event. PMID:10334486

  12. The Rag-Ragulator Complex Regulates Lysosome Function and Phagocytic Flux in Microglia

    PubMed Central

    Shen, Kimberle; Sidik, Harwin; Talbot, William S.

    2016-01-01

    Microglia are resident macrophages of the CNS that are essential for phagocytosis of apoptotic neurons and weak synapses during development. We show that RagA and Lamtor4, two components of the Rag-Ragulator complex, are essential regulators of lysosomes in microglia. In zebrafish lacking RagA function, microglia exhibit an expanded lysosomal compartment but are unable to properly digest apoptotic neuronal debris. Previous biochemical studies have placed the Rag-Ragulator complex upstream of mTORC1 activation in response to cellular nutrient availability. Nonetheless, RagA and mTOR mutant zebrafish have distinct phenotypes, indicating that the Rag-Ragulator complex has functions independent of mTOR signaling. Our analysis reveals an essential role of the Rag-Ragulator complex in proper lysosome function and phagocytic flux in microglia. PMID:26774477

  13. Effect of NDP-α-MSH on PPAR-γ and –β Expression and Anti-Inflammatory Cytokine Release in Rat Astrocytes and Microglia

    PubMed Central

    Carniglia, Lila; Durand, Daniela; Caruso, Carla; Lasaga, Mercedes

    2013-01-01

    Brain inflammation plays a central role in numerous brain pathologies. Microglia and astrocytes are the main effector cells that become activated when an inflammatory process takes place within the central nervous system. α-melanocyte-stimulating hormone (α-MSH) is a neuropeptide with proven anti-inflammatory properties. It binds with highest affinity to the melanocortin receptor 4 (MC4R), which is present in astrocytes and upon activation triggers anti-inflammatory pathways. The aim of this research was to identify anti-inflammatory mediators that may participate in the immunomodulatory effects of melanocortins in glial cells. Since peroxisome proliferator-activated receptors (PPARs) have recently been implicated in the modulation of inflammation, we investigated the effect of an α-MSH analog, [Nle4, D-Phe7]-α-MSH (NDP-α-MSH), on PPAR-β and PPAR-γ gene and protein expression in rat primary astrocytes and microglia. We initially demonstrated that rat primary microglia express MC4R and showed that treatment with NDP-α-MSH increases PPAR-γ protein levels and strongly decreases PPAR-β levels in both astrocytes and microglia. We also showed that extracellular signal-regulated kinase 1/2 (ERK1/2)–mediated signaling is partially involved in these effects in a cell-specific fashion. Finally, we showed that NDP-α-MSH stimulates the release of the anti-inflammatory cytokines IL-10 and TGF-β from microglia and astrocytes, respectively. The presented data suggest a role for IL-10 and TGF-β in the protective action of melanocortins and a connection between MC4R pathway and that of the nuclear receptor PPAR-γ. This is the first report providing evidence that MC4R is expressed in rat primary microglia and that melanocortins modulate PPAR levels in glial cells. Our findings provide new insights into the mechanisms underlying the activation of glial MC4R and open perspectives for new therapeutic strategies for the treatment of inflammation-mediated brain diseases

  14. Construction of AAV-rat-IL4 and Evaluation of its Modulating Effect on Aβ (1-42)-Induced Proinflammatory Cytokines in Primary Microglia and the B92 Cell Line by Quantitative PCR Assay

    PubMed Central

    Jamalidoust, Marzieh; Ravanshad, Mehrdad; Namayandeh, Mandana; Zare, Maryam; Asaei, Sadaf; Ziyaeyan, Mazyar

    2016-01-01

    Background Interleukin-4 (IL-4), as the most prominent anti-inflammatory cytokine, plays an important role in modulating microglial activation and inflammatory responses in Alzheimer’s disease (AD), a chronic inflammatory disorder. Objectives The current study aimed to develop a new recombinant Adeno-associated viral (rAAV) vector that delivers IL-4 and then assess the counterbalancing effect of the new construct along with recombinant IL-4 (rIL-4) protein in in-vitro models of AD. Materials and Methods The rAAV-IL4 was originally prepared and then employed along with rIL-4 protein to counter Amyloid β (1-42)-induced proinflammatory cytokines in a primary microglia cell culture and the B92 rat microglia continuous cell line, using relative Real-Time PCR assay. Results Aβ (1-42) stimulated the production of the proinflammatory cytokines IL6, IL1β, TNFα, and IL18 in both the primary microglia cell culture and the B92 cell line. Both the rAAV-IL4 construct and the rIL-4 protein were found to inhibit production of the most important Aβ (1-42)-induced proinflammatory cytokine mRNAs in the two types of cells with different patterns. Conclusions It seems that the new construct can serve as an appropriate option in the modulation of Aβ-induced proinflammatory cytokine gene expression and microglia activation in patients affected by AD. PMID:27217922

  15. Measurements of Heart Rate and Accelerometry to Determine the Physical Activity Level in Boys Playing Paintball

    PubMed Central

    JARVI, MICHELLE; BROWN, GREGORY A; SHAW, BRANDON S.; SHAW, INA

    2013-01-01

    Paintball is a popular recreational sport played by 3.655 million Americans and may be sufficient physical activity to promote health. Paintball has been played as an organized sport since the 1980’s and is essentially a game of tag, except instead of touching an opponent by hand opponents are tagged by shooting them with a paintball that leaves a mark indicating who has been eliminated. A previous evaluation of paintball as physical activity had 13 subjects undergo a VO2max test to develop a heart rate (HR) /oxygen consumption relationship, and it was observed that heart rates during paintball were 68–73% of the measured maximal HR. The present study used accelerometry and HR monitors to evaluate the quantity and intensity of physical activity in boys playing paintball. Eleven boys (12.7 ± 1.0 y, 51.5 ± 11.3 kg, 161.8 ± 10.1 cm) engaged in a VO2max test to develop a HR/oxygen consumption correlation. On a separate day the boys played 7 games of outdoor paintball while wearing a HR monitor and accelerometer. The boys played paintball for 11.5 ± 6.2 minutes/game for a total of 80.6 ± 10.0 minutes of game play. Average HR during paintball play was 129.6 ± 6.6 beats/min, representing 39.9 ± 12.9% VO2max. Based on accelerometry, the boys accumulated 63.2 ± 15.6 minutes of moderate intensity activity and 2.6 ± 2.8 minutes of vigorous activity during paintball. These data suggest that playing paintball may be considered as physical activity that is > 3 METs, and thus health promoting. PMID:27182396

  16. Microglia: Architects of the Developing Nervous System.

    PubMed

    Frost, Jeffrey L; Schafer, Dorothy P

    2016-08-01

    Microglia are resident macrophages of the central nervous system (CNS), representing 5-10% of total CNS cells. Recent findings reveal that microglia enter the embryonic brain, take up residence before the differentiation of other CNS cell types, and become critical regulators of CNS development. Here, we discuss exciting new work implicating microglia in a range of developmental processes, including regulation of cell number and spatial patterning of CNS cells, myelination, and formation and refinement of neural circuits. Furthermore, we review studies suggesting that these cellular functions result in the modulation of behavior, which has important implications for a variety of neurological disorders. PMID:27004698

  17. Anti-Inflammatory Effects of 3-(4'-Hydroxyl-3',5'-Dimethoxyphenyl)Propionic Acid, an Active Component of Korean Cabbage Kimchi, in Lipopolysaccharide-Stimulated BV2 Microglia.

    PubMed

    Jeong, Jin-Woo; Choi, Il-Whan; Jo, Guk-Heui; Kim, Gi-Young; Kim, Jinwoo; Suh, Hongsuk; Ryu, Chung-Ho; Kim, Wun-Jae; Park, Kun-Young; Choi, Yung Hyun

    2015-06-01

    We investigated the protective ability of 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA), an active principle in Korean cabbage kimchi, against the production of proinflammatory mediators and cytokines, and the mechanisms involved in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. HDMPPA significantly suppressed the production of nitric oxide (NO) and prostaglandin E2, along with the expression of inducible NO synthase and cyclooxygenase-2 in LPS-stimulated BV2 cells, at concentrations with no cytotoxicity. HDMPPA also attenuated the LPS-induced expression and secretion of proinflammatory cytokines, such as tumor necrosis factor-α and interleukin-1β. Furthermore, HDMPPA inhibited LPS-induced nuclear factor-κB (NF-κB) activation, which was associated with the abrogation of IκB-α degradation and phosphorylation, and subsequent decreases in NF-κB p65 levels. Moreover, the phosphorylation of mitogen-activated protein kinases (MAPKs) and Akt, a downstream molecule of phosphatidylinositol-3-kinase (PI3K), in LPS-stimulated BV2 cells was suppressed markedly by HDMPPA. This effect was associated with a significant reduction in the formation of intracellular reactive oxygen species. The findings in this study suggest that HDMPPA may exert anti-inflammatory responses by suppressing LPS-induced expression of proinflammatory mediators and cytokines through blockage of NF-κB, MAPKs, and PI3K/Akt signaling pathways and oxidative stress in microglia. PMID:25919915

  18. Janus-faced microglia: beneficial and detrimental consequences of microglial phagocytosis

    PubMed Central

    Sierra, Amanda; Abiega, Oihane; Shahraz, Anahita; Neumann, Harald

    2012-01-01

    Microglia are the resident brain macrophages and they have been traditionally studied as orchestrators of the brain inflammatory response during infections and disease. In addition, microglia has a more benign, less explored role as the brain professional phagocytes. Phagocytosis is a term coined from the Greek to describe the receptor-mediated engulfment and degradation of dead cells and microbes. In addition, microglia phagocytoses brain-specific cargo, such as axonal and myelin debris in spinal cord injury or multiple sclerosis, amyloid-β deposits in Alzheimer's disease, and supernumerary synapses in postnatal development. Common mechanisms of recognition, engulfment, and degradation of the different types of cargo are assumed, but very little is known about the shared and specific molecules involved in the phagocytosis of each target by microglia. More importantly, the functional consequences of microglial phagocytosis remain largely unexplored. Overall, phagocytosis is considered a beneficial phenomenon, since it eliminates dead cells and induces an anti-inflammatory response. However, phagocytosis can also activate the respiratory burst, which produces toxic reactive oxygen species (ROS). Phagocytosis has been traditionally studied in pathological conditions, leading to the assumption that microglia have to be activated in order to become efficient phagocytes. Recent data, however, has shown that unchallenged microglia phagocytose apoptotic cells during development and in adult neurogenic niches, suggesting an overlooked role in brain remodeling throughout the normal lifespan. The present review will summarize the current state of the literature regarding the role of microglial phagocytosis in maintaining tissue homeostasis in health as in disease. PMID:23386811

  19. Eliminating microglia in Alzheimer's mice prevents neuronal loss without modulating amyloid-β pathology.

    PubMed

    Spangenberg, Elizabeth E; Lee, Rafael J; Najafi, Allison R; Rice, Rachel A; Elmore, Monica R P; Blurton-Jones, Mathew; West, Brian L; Green, Kim N

    2016-04-01

    In addition to amyloid-β plaque and tau neurofibrillary tangle deposition, neuroinflammation is considered a key feature of Alzheimer's disease pathology. Inflammation in Alzheimer's disease is characterized by the presence of reactive astrocytes and activated microglia surrounding amyloid plaques, implicating their role in disease pathogenesis. Microglia in the healthy adult mouse depend on colony-stimulating factor 1 receptor (CSF1R) signalling for survival, and pharmacological inhibition of this receptor results in rapid elimination of nearly all of the microglia in the central nervous system. In this study, we set out to determine if chronically activated microglia in the Alzheimer's disease brain are also dependent on CSF1R signalling, and if so, how these cells contribute to disease pathogenesis. Ten-month-old 5xfAD mice were treated with a selective CSF1R inhibitor for 1 month, resulting in the elimination of ∼80% of microglia. Chronic microglial elimination does not alter amyloid-β levels or plaque load; however, it does rescue dendritic spine loss and prevent neuronal loss in 5xfAD mice, as well as reduce overall neuroinflammation. Importantly, behavioural testing revealed improvements in contextual memory. Collectively, these results demonstrate that microglia contribute to neuronal loss, as well as memory impairments in 5xfAD mice, but do not mediate or protect from amyloid pathology. PMID:26921617

  20. Participation in play activities: a single-case study focusing on a child with obesity experiences.

    PubMed

    Skär, Lisa; Prellwitz, Maria

    2008-06-01

    The purpose of this study was to describe how a child with obesity perceived participation in play activities. A single-case study design was chosen to optimize the understanding of the complexities of the research question. A 9-year-old boy diagnosed with obesity was studied. This is a typical case and is studied mainly to provide understanding to the issue. The data were collected from interviews with the boy, his mother and his teacher. Data were also collected through observations and a self-report assessment instrument called Kid Play Profile. The results showed that the boy was ridiculed by his peers and that at times he felt excluded from them, which prevented him from participating in play activities. The boy's experience came from different perceived problems such as lack of friends to play with, his inability to know how to perform in different play activities, and lack of proper support and encouragement from adults. Supporting children to overcome social skills deficits could prevent them from being teased and may have a positive effect on health. To optimize children's participation in play activities, it is important for adults to give them proper support and encouragement. The results were discussed with regard to earlier research, and topics for further research are suggested. PMID:18489691

  1. Read, Play, and Learn! Storybook Activities for Young Children. The Transdisciplinary Play-Based Curriculum. Collection 1: Modules 1-8.

    ERIC Educational Resources Information Center

    Linder, Toni W.

    Read, Play, and Learn is a play-based curriculum designed to promote growth across all of the areas of development important to a young child. With a school-year's worth of ready-to-use lessons or modules, the curriculum provides story-related activities centered around themes such as enjoying seasonal festivities, sharing emotions, making…

  2. Read, Play, and Learn! Storybook Activities for Young Children. The Transdisciplinary Play-Based Curriculum. Collection 2: Modules 9-16.

    ERIC Educational Resources Information Center

    Linder, Toni W.

    Read, Play, and Learn is a play-based curriculum designed to promote growth across all of the areas of development important to a young child. With a school-year's worth of ready-to-use lessons or modules, the curriculum provides story-related activities centered around themes such as enjoying seasonal festivities, sharing emotions, making…

  3. Solitary-Functional Play and Solitary-Pretend Play: Another Look at the Construct of Solitary-Active Behavior Using Playground Observations

    ERIC Educational Resources Information Center

    Nelson, Larry J.; Hart, Craig H.; Evans, Cortney A.

    2008-01-01

    Although the construct of solitary-active behavior calls for the aggregation of solitary-functional play and solitary-pretend play, there is little empirical support for combining them into one construct. Furthermore, little work has been done in early childhood to examine these behaviors on the playground. The purpose of this study was to observe…

  4. Integrated Expression Profiles of mRNA and miRNA in Polarized Primary Murine Microglia

    PubMed Central

    Freilich, Robert W.; Woodbury, Maya E.; Ikezu, Tsuneya

    2013-01-01

    Neuroinflammation contributes to many neurologic disorders including Alzheimer’s disease, multiple sclerosis, and stroke. Microglia is brain resident myeloid cells and have emerged as a key driver of the neuroinflammatory responses. MicroRNAs (miRNAs) provide a novel layer of gene regulation and play a critical role in regulating the inflammatory response of peripheral macrophages. However, little is known about the miRNA in inflammatory activation of microglia. To elucidate the role that miRNAs have on microglial phenotypes under classical (M1) or alternative (M2) activation under lipopolysaccharide (‘M1’-skewing) and interleukin-4 (‘M2a’-skewing) stimulation conditions, we performed microarray expression profiling and bioinformatics analysis of both mRNA and miRNA using primary cultured murine microglia. miR-689, miR-124, and miR-155 were the most strongly associated miRNAs predicted to mediate pro-inflammatory pathways and M1-like activation phenotype. miR-155, the most strongly up-regulated miRNA, regulates the signal transducer and activator of transcription 3 signaling pathway enabling the late phase response to M1-skewing stimulation. Reduced expression in miR-689 and miR-124 are associated with dis-inhibition of many canonical inflammatory pathways. miR-124, miR-711, miR-145 are the strongly associated miRNAs predicted to mediate anti-inflammatory pathways and M2-like activation phenotype. Reductions in miR-711 and miR-124 may regulate inflammatory signaling pathways and peroxisome proliferator-activated receptor-gamma pathway. miR-145 potentially regulate peripheral monocyte/macrophage differentiation and faciliate the M2-skewing phenotype. Overall, through combined miRNA and mRNA expression profiling and bioinformatics analysis we have identified six miRNAs and their putative roles in M1 and M2-skewing of microglial activation through different signaling pathways. PMID:24244499

  5. Children with Autism Spectrum Disorder and Patterns of Participation in Daily Physical and Play Activities

    PubMed Central

    Memari, Amir Hossein; Panahi, Nekoo; Ranjbar, Elaheh; Moshayedi, Pouria; Shafiei, Masih; Kordi, Ramin; Ziaee, Vahid

    2015-01-01

    Autism spectrum disorder (ASD) indicates several neurodevelopmental impairments which may end in impairments in motor or physical activities. Daily physical activity involvement was investigated in a total of 83 children (52 boys and 31 girls) with ASD aged 6–15 years. Results indicated that only 10 (12%) of children with ASD were physically active. Children were predominantly engaged in solitary play rather than social play activities. Gender, family income, and household structure were found to be associated with activity scores. Financial burden and lack of opportunities were noted as the leading barriers to physical activities. In conclusion, findings indicated a low rate of physical activity participation in children with ASD that is closely associated with sociodemographic variables. PMID:26171247

  6. Is Father-Child Rough-and-Tumble Play Associated with Attachment or Activation Relationships?

    ERIC Educational Resources Information Center

    Paquette, Daniel; Dumont, Caroline

    2013-01-01

    The activation relationship theory, primarily focused on parental stimulation of risk-taking along with parental control during exploration, predicts that boys will be activated more than girls by their fathers. This theory may explain why fathers engage in rough-and-tumble play (RTP) with children more frequently than mothers, especially with…

  7. Understanding Our Environment: Challenge. Clear Water Challenge: A Role Play Activity.

    ERIC Educational Resources Information Center

    Lieblich, Suzanne, Ed.

    Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activity and direct experience, this unit contains a role-play activity in the form of a public inquiry into the cause of a fish kill on a river that runs through the fictional town of Oakwood. A…

  8. Playing "The Ladybug Game": Parent Guidance of Young Children's Numeracy Activities

    ERIC Educational Resources Information Center

    Vandermaas-Peeler, Maureen; Ferretti, Larissa; Loving, Sara

    2012-01-01

    Parent guidance for numeracy activities and preschoolers' numeracy performance were examined in the context of playing a board game in three sessions over a two-week period. Twenty-eight parent-child dyads were randomly assigned to a numeracy awareness group in which parents were provided with suggested numeracy activities to incorporate into the…

  9. Affordances in Outdoor Environments and Children's Physically Active Play in Pre-School

    ERIC Educational Resources Information Center

    Storli, Rune; Hagen, Trond Loge

    2010-01-01

    The purpose of this article is to quantitatively and qualitatively explore children's physically active play outdoors in a traditional playground and natural (nature) environment and discuss how these environments influence children's physical activity. Fjortoft has previously explored the relationship between environmental affordances and…

  10. Role Play Simulations: The Assessment of an Active Learning Technique and Comparisons with Traditional Lectures.

    ERIC Educational Resources Information Center

    DeNeve, Kristina; Heppner, Mary J.

    1997-01-01

    Use of active learning techniques of role-playing and simulation in an industrial psychology course (n=29 students) is described and assessed. Subjective reports and objective assessments of knowledge retention indicate the approach was effective. The differential importance of active learning and passive learning (lecture) in the college…

  11. Influencing Preschoolers' Free-Play Activity Preferences: An Evaluation of Satiation and Embedded Reinforcement

    ERIC Educational Resources Information Center

    Hanley, Gregory P.; Tiger, Jeffrey H.; Ingvarsson, Einar T.; Cammilleri, Anthony P.

    2009-01-01

    The present study evaluated the effects of classwide satiation and embedded reinforcement procedures on preschoolers' activity preferences during scheduled free-play periods. The goal of the study was to increase time allocation to originally nonpreferred, but important, activities (instructional zone, library, and science) while continuing to…

  12. Plan before You Play: An Activity for Teaching the Managerial Process

    ERIC Educational Resources Information Center

    Althouse, Norm R.; Hedges, Peggy L.

    2015-01-01

    This article describes a 60-minute classroom activity using LEGO® bricks that demonstrates and reinforces the importance of the managerial process. The activity, Plan Before You Play (PBP), is targeted to introductory business classes, and differs from others in that it requires little investment or up-front planning, is easily scalable, and, with…

  13. Narrative increases step counts during active video game play among children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Active video games (AVGs) capable of inducing physical activity (PA) level offer a novel alternative to child obesity. Unfortunately, children's motivation to play AVG decreases quickly, underscoring the need to find new methods to maintain their engagement. According to narrative transportation th...

  14. 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*

    PubMed Central

    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

    2014-01-01

    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 Ca2+ concentration ([Ca2+]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 [Ca2+]i in rodent microglial cells. We observed that canonical transient receptor potential 3 (TRPC3) channels contribute to the maintenance of BDNF-induced sustained intracellular Ca2+ 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 Ca2+ 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. PMID:24811179

  15. 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.

    PubMed

    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. PMID:24811179

  16. Neuroprotection of Neuro2a cells and the cytokine suppressive and anti-inflammatory mode of action of resveratrol in activated RAW264.7 macrophages and C8-B4 microglia.

    PubMed

    Steiner, Nicole; Balez, Rachelle; Karunaweera, Niloo; Lind, Joanne M; Münch, Gerald; Ooi, Lezanne

    2016-05-01

    Chronic inflammation is a hallmark of neurodegenerative disease and cytotoxic levels of nitric oxide (NO) and pro-inflammatory cytokines can initiate neuronal death pathways. A range of cellular assays were used to assess the anti-inflammatory and neuroprotective action of resveratrol using murine microglial (C8-B4), macrophage (RAW264.7) and neuronal-like (Neuro2a) cell lines. We examined the release of NO by Griess assay and used a Bioplex array to measure a panel of pro- and anti-inflammatory cytokines and chemokines, in response to the inflammatory stimuli lipopolysaccharide (LPS) and interferon-γ (IFN-γ). Resveratrol was a potent inhibitor of NO and cytokine release in activated macrophages and microglia. The activity of resveratrol increased marginally in potency with longer pre-incubation times in cell culture that was not due to cytotoxicity. Using an NO donor we show that resveratrol can protect Neuro2a cells from cytotoxic concentrations of NO. The protective effect of resveratrol from pro-inflammatory signalling in RAW264.7 cells was confirmed in co-culture experiments leading to increased survival of Neuro2a cells. Together our data are indicative of the potential neuroprotective effect of resveratrol during nitrosative stress and neuroinflammation. PMID:26522689

  17. Where they live, how they play: Neighborhood greenness and outdoor physical activity among preschoolers

    PubMed Central

    2011-01-01

    Background Emerging empirical evidence suggests exposure to "green" environments may encourage higher levels of physical activity among children. Few studies, however, have explored this association exclusively in pre-school aged children in the United States. We examined whether residing in neighborhoods with higher levels of greenness was associated with higher levels of outdoor physical activity among preschoolers. In addition, we also explored whether outdoor playing behaviors (e.g., active vs. quiet) were influenced by levels of neighborhood greenness independent of demographic and parental support factors. Results Higher levels of neighborhood greenness as measured by the Normalized Difference Vegetation Index (NDVI) was associated with higher levels of outdoor playing time among preschool-aged children in our sample. Specifically, a one unit increase in neighborhood greenness increased a child's outdoor playing time by approximately 3 minutes. A dose-response relationship was observed between increasing levels of parental support for physical activity (e.g., time spent playing with children) and child outdoor physical activity (p < 0.01). Conclusions Consistent with previous studies, neighborhood greenness influences physical activity behavior. However, for preschoolers, parental involvement may be more critical for improving physical activity levels. PMID:22165919

  18. HybridPLAY: A New Technology to Foster Outdoors Physical Activity, Verbal Communication and Teamwork.

    PubMed

    Díaz, Diego José; Boj, Clara; Portalés, Cristina

    2016-01-01

    This paper presents HybridPLAY, a novel technology composed of a sensor and mobile-based video games that transforms urban playgrounds into game scenarios. With this technology we aim to stimulate physical activity and playful learning by creating an entertaining environment in which users can actively participate and collaborate. HybridPLAY is different from other existing technologies that enhance playgrounds, as it is not integrated in them but can be attached to the different elements of the playgrounds, making its use more ubiquitous (i.e., not restricted to the playgrounds). HybridPLAY was born in 2007 as an artistic concept, and evolved after different phases of research and testing by almost 2000 users around the world (in workshops, artistic events, conferences, etc.). Here, we present the temporal evolution of HybridPLAY with the different versions of the sensors and the video games, and a detailed technical description of the sensors and the way interactions are produced. We also present the outcomes after the evaluation by users at different events and workshops. We believe that HybridPLAY has great potential to contribute to increased physical activity in kids, and also to improve the learning process and monitoring at school centres by letting users create the content of the apps, leading to new narratives and fostering creativity. PMID:27120601

  19. HybridPLAY: A New Technology to Foster Outdoors Physical Activity, Verbal Communication and Teamwork

    PubMed Central

    Díaz, Diego José; Boj, Clara; Portalés, Cristina

    2016-01-01

    This paper presents HybridPLAY, a novel technology composed of a sensor and mobile-based video games that transforms urban playgrounds into game scenarios. With this technology we aim to stimulate physical activity and playful learning by creating an entertaining environment in which users can actively participate and collaborate. HybridPLAY is different from other existing technologies that enhance playgrounds, as it is not integrated in them but can be attached to the different elements of the playgrounds, making its use more ubiquitous (i.e., not restricted to the playgrounds). HybridPLAY was born in 2007 as an artistic concept, and evolved after different phases of research and testing by almost 2000 users around the world (in workshops, artistic events, conferences, etc.). Here, we present the temporal evolution of HybridPLAY with the different versions of the sensors and the video games, and a detailed technical description of the sensors and the way interactions are produced. We also present the outcomes after the evaluation by users at different events and workshops. We believe that HybridPLAY has great potential to contribute to increased physical activity in kids, and also to improve the learning process and monitoring at school centres by letting users create the content of the apps, leading to new narratives and fostering creativity. PMID:27120601

  20. Microglia/Macrophages Migrate through Retinal Epithelium Barrier by a Transcellular Route in Diabetic Retinopathy

    PubMed Central

    Omri, Samy; Behar-Cohen, Francine; de Kozak, Yvonne; Sennlaub, Florian; Mafra Verissimo, Lourena; Jonet, Laurent; Savoldelli, Michèle; Omri, Boubaker; Crisanti, Patricia

    2011-01-01

    Diabetic retinopathy is associated with ocular inflammation, leading to retinal barrier breakdown, macular edema, and visual cell loss. We investigated the molecular mechanisms involved in microglia/macrophages trafficking in the retina and the role of protein kinase Cζ (PKCζ) in this process. Goto Kakizaki (GK) rats, a model for spontaneous type 2 diabetes were studied until 12 months of hyperglycemia. Up to 5 months, sparse microglia/macrophages were detected in the subretinal space, together with numerous pores in retinal pigment epithelial (RPE) cells, allowing inflammatory cell traffic between the retina and choroid. Intercellular adhesion molecule–1 (ICAM-1), caveolin-1 (CAV-1), and PKCζ were identified at the pore border. At 12 months of hyperglycemia, the significant reduction of pores density in RPE cell layer was associated with microglia/macrophages accumulation in the subretinal space together with vacuolization of RPE cells and disorganization of photoreceptors outer segments. The intraocular injection of a PKCζ inhibitor at 12 months reduced iNOS expression in microglia/macrophages and inhibited their migration through the retina, preventing their subretinal accumulation. We show here that a physiological transcellular pathway takes place through RPE cells and contributes to microglia/macrophages retinal trafficking. Chronic hyperglycemia causes alteration of this pathway and subsequent subretinal accumulation of activated microglia/macrophages. PMID:21712024

  1. De novo expression of dopamine D2 receptors on microglia after stroke.

    PubMed

    Huck, Jojanneke H J; Freyer, Dorette; Böttcher, Chotima; Mladinov, Mihovil; Muselmann-Genschow, Claudia; Thielke, Mareike; Gladow, Nadine; Bloomquist, Dana; Mergenthaler, Philipp; Priller, Josef

    2015-11-01

    Dopamine is the predominant catecholamine in the brain and functions as a neurotransmitter. Dopamine is also a potent immune modulator. In this study, we have characterized the expression of dopamine receptors on murine microglia. We found that cultured primary microglia express dopamine D1, D2, D3, D4, and D5 receptors. We specifically focused on the D2 receptor (D2R), a major target of antipsychotic drugs. Whereas D2Rs were strongly expressed on striatal neurons in vivo, we did not detect any D2R expression on resident microglia in the healthy brains of wild-type mice or transgenic mice expressing the green fluorescent protein (GFP) under the control of the Drd2 promoter. However, cerebral ischemia induced the expression of D2R on Iba1-immunoreactive inflammatory cells in the infarct core and penumbra. Notably, D2R expression was confined to CD45(hi) cells, and GFP BM chimeras revealed that D2R was expressed on activated resident microglia as well as on peripherally derived macrophages in the ischemic brain. Importantly, the D2/3R agonist, pramipexole, enhanced the secretion of nitrite by cultured microglia in response to proinflammatory stimuli. Thus, dopamine may serve as a modulator of microglia function during neuroinflammation. PMID:26104289

  2. When human immunodeficiency virus meets chemokines and microglia: neuroprotection or neurodegeneration?

    PubMed

    Mocchetti, Italo; Campbell, Lee A; Harry, G Jean; Avdoshina, Valeriya

    2013-03-01

    Chemokines are chemotactic cytokines that were originally discovered as promoters of leukocyte proliferation and mobility. In recent years, however, evidence has demonstrated constitutive expression of chemokines and chemokine receptors in a variety of cells in the central and peripheral nervous system and has proposed a role for chemokines in neurodegenerative diseases characterized by inflammation and microglia proliferation. In addition, chemokine receptors, and in particular CXCR4 and CCR5, mediate human immunodeficiency virus type 1 (HIV) infection of immunocompetent cells as well as microglia. Subsequently, HIV, through a variety of mechanisms, promotes synapto-dendritic alterations and neuronal loss that ultimately lead to motor and cognitive impairments. These events are accompanied by microglia activation. Nevertheless, a microglia-mediated mechanism of neuronal degeneration alone cannot fully explain some of the pathological features of HIV infected brain such as synaptic simplification. In this article, we present evidence that some of the microglia responses to HIV are beneficial and neuroprotective. These include the ability of microglia to release anti-inflammatory cytokines, to remove dying cells and to promote axonal sprouting. PMID:22527632

  3. Anti-inflammatory role of the isoflavone diadzein in lipopolysaccharide-stimulated microglia: implications for Parkinson's disease.

    PubMed

    Chinta, Shankar J; Ganesan, Abirami; Reis-Rodrigues, Pedro; Lithgow, Gordon J; Andersen, Julie K

    2013-02-01

    Microglial activation and subsequent release of toxic pro-inflammatory factors are believed to play an important role in neuronal cell death associated with Parkinson's disease (PD). Compounds that inhibit microglia activation and suppress pro-inflammatory factor release have been reported to have neuroprotective effects in animal models of PD. In this study, we tested whether diadzein, a natural isoflavone found in soybean, attenuated lipopolysaccharide (LPS)-induced release of inflammatory mediators in BV-2, a murine microglial cell line. Diadzein pretreatment was found to significantly suppress the production of the pro-inflammatory factors nitric oxide and IL-6 as well as their mRNA expression in conjunction with reductions in ROS production, p38 MAPK phosphorylation, and NF-κB activation. Furthermore, transfer of conditioned media (CM) from BV-2 cells pretreated with diadzein resulted in a significantly reduction in dopaminergic neurotoxicity compared with CM from microglia stimulated with LPS alone. Together, our results suggest that diadzein's neuroprotective properties may be due to its ability to dampen induction of microglial activation and the subsequent release of soluble pro-inflammatory factors. This appears to be via inhibition of oxidative induction of the p38 MAP kinase-NFκB pathway, resulting in reduced expression of pro-inflammatory genes and release of their corresponding gene products. PMID:22573480

  4. Differential Transcriptome Networks between IDO1-Knockout and Wild-Type Mice in Brain Microglia and Macrophages

    PubMed Central

    Gonzalez-Pena, Dianelys; Nixon, Scott E.; Southey, Bruce R.; Lawson, Marcus A.; McCusker, Robert H.; Hernandez, Alvaro G.; Dantzer, Robert; Kelley, Keith W.; Rodriguez-Zas, Sandra L.

    2016-01-01

    Microglia in the brain and macrophages in peripheral organs are cell types responsible for immune response to challenges. Indoleamine 2,3-dioxygenase 1 (IDO1) is an immunomodulatory enzyme of the tryptophan pathway that is expressed in the brain. The higher activity of IDO1 in response to immune challenge has been implicated in behavioral disorders. The impact of IDO1 depletion on the microglia transcriptome has not been studied. An investigation of the transcript networks in the brain microglia from IDO1-knockout (IDO1-KO) mice was undertaken, relative to peripheral macrophages and to wild-type (WT) mice under unchallenged conditions. Over 105 transcript isoforms were differentially expressed between WT and IDO1-KO within cell type. Within microglia, Saa3 and Irg1 were over-expressed in IDO1-KO relative to WT. Within macrophages, Csf3 and Sele were over-expressed in IDO1-KO relative to WT. Among the genes differentially expressed between strains, enriched biological processes included ion homeostasis and ensheathment of neurons within microglia, and cytokine and chemokine expression within macrophages. Over 11,110 transcript isoforms were differentially expressed between microglia and macrophages and of these, over 10,800 transcripts overlapped between strains. Enriched biological processes among the genes over- and under-expressed in microglia relative to macrophages included cell adhesion and apoptosis, respectively. Detected only in microglia or macrophages were 421 and 43 transcript isoforms, respectively. Alternative splicing between cell types based on differential transcript isoform abundance was detected in 210 genes including Phf11d, H2afy, and Abr. Across strains, networks depicted a predominance of genes under-expressed in microglia relative to macrophages that may be a precursor for the different response of both cell types to challenges. The detected transcriptome differences enhance the understanding of the role of IDO1 in the microglia transcriptome

  5. Human and Mouse Microglia Express Connexin36, and Functional Gap Junctions Are Formed Between Rodent Microglia and Neurons

    PubMed Central

    Dobrenis, K.; Chang, H.-Y.; Pina-Benabou, M.H.; Woodroffe, A.; Lee, S.C.; Rozental, R.; Spray, D.C.; Scemes, E.

    2008-01-01

    Microglia, the tissue macrophages of the central nervous system (CNS), intimately interact with neurons physically and through soluble factors that can affect microglial activation state and neuronal survival and physiology. We report here a new mechanism of interaction between these cells, provided by the formation of gap junctions composed of connexin (Cx) 36. Among eight Cxs tested, expression of Cx36 mRNA and protein was found in microglial cultures prepared from human and mouse, and Cx45 mRNA was found in mouse microglial cultures. Electrophysiological measurements found coupling between one-third of human or mouse microglial pairs that averaged below 30 pico-Siemens and displayed electrical properties consistent with Cx36 gap junctions. Importantly, similar frequency of low-strength electrical coupling was also obtained between microglia and neurons in cocultures prepared from neocortical or hippocampal rodent tissue. Lucifer yellow dye coupling between neurons and microglia was observed in 4% of pairs tested, consistent with the low strength and incidence of electrical coupling. Cx36 expression level and/or the degree of coupling between microglia did not significantly change in the presence of activating agents, including lipopolysaccharide, granulocyte-macrophage colony-stimulating factor, interferon-γ, and tumor necrosis factor-α, except for some reduction of Cx36 protein when exposed to the latter two agents. Our findings that intercellular coupling occurs between neuronal and microglial populations through Cx36 gap junctions have potentially important implications for normal neural physiology and microglial responses in neuronopathology in the mammalian CNS. PMID:16211561

  6. Age-dependent accumulation of lipofuscin in perivascular and subretinal microglia in experimental mice.

    PubMed

    Xu, Heping; Chen, Mei; Manivannan, Ayyakkannu; Lois, Noemi; Forrester, John V

    2008-01-01

    Fundus autofluorescence (AF) imaging by confocal scanning laser ophthalmoscopy has been widely used by ophthalmologists in the diagnosis/monitoring of various retinal disorders. It is believed that fundus AF is derived from lipofuscin in retinal pigment epithelial (RPE) cells; however, direct clinicopathological correlation has not been possible in humans. We examined fundus AF by confocal scanning laser ophthalmoscopy and confocal microscopy in normal C57BL/6 mice of different ages. Increasingly strong AF signals were observed with age in the neuroretina and subretinal/RPE layer by confocal scanning laser ophthalmoscopy. Unlike fundus AF detected in normal human subjects, mouse fundus AF appeared as discrete foci distributed throughout the retina. Most of the AF signals in the neuroretina were distributed around retinal vessels. Confocal microscopy of retinal and choroid/RPE flat mounts demonstrated that most of the AF signals were derived from Iba-1+ perivascular and subretinal microglia. An age-dependent accumulation of Iba-1+ microglia at the subretinal space was observed. Lipofuscin granules were detected in large numbers in subretinal microglia by electron microscopy. The number of AF+ microglia and the amount of AF granules/cell increased with age. AF granules/lipofuscin were also observed in RPE cells in mice older than 12 months, but the number of AF+ RPE cells was very low (1.48 mm(-2) and 5.02 mm(-2) for 12 and 24 months, respectively) compared to the number of AF+ microglial cells (20.63 mm(-2) and 76.36 mm(-2) for 6 and 24 months, respectively). The fluorescence emission fingerprints of AF granules in subretinal microglia were the same as those in RPE cells. Our observation suggests that perivascular and subretinal microglia are the main cells producing lipofuscin in normal aged mouse retina and are responsible for in vivo fundus AF. Microglia may play an important role in retinal aging and age-related retinal diseases. PMID:17988243

  7. Can we switch microglia's phenotype to foster neuroprotection? Focus on multiple sclerosis

    PubMed Central

    Giunti, Debora; Parodi, Benedetta; Cordano, Christian; Uccelli, Antonio; Kerlero de Rosbo, Nicole

    2014-01-01

    Microglia cells, the resident innate immune cells in the brain, are highly active, extending and retracting highly motile processes through which they continuously survey their microenvironment for ‘danger signals’ and interact dynamically with surrounding cells. Upon sensing changes in their central nervous system microenvironment, microglia become activated, undergoing morphological and functional changes. Microglia activation is not an ‘all-or-none’ process, but rather a continuum depending on encountered stimuli, which is expressed through a spectrum of molecular and functional phenotypes ranging from so-called ‘classically activated’, with a highly pro-inflammatory profile, to ‘alternatively activated’ associated with a beneficial, less inflammatory, neuroprotective profile. Microglia activation has been demonstrated in most neurological diseases of diverse aetiology and has been implicated as a contributor to neurodegeneration. The possibility to promote microglia’s neuroprotective phenotype has therefore become a therapeutic goal. We have focused our discussion on the role of microglia in multiple sclerosis, a prototype of inflammatory, demyelinating, neurodegenerative disease, and on the effect of currently approved or on-trial anti-inflammatory therapeutic strategies that might mediate neuroprotection at least in part through their effect on microglia by modifying their behaviour via a switch of their functional phenotype from a detrimental to a protective one. In addition to pharmaceutical approaches, such as treatment with glatiramer acetate, interferon-β, fingolimod or dimethyl fumarate, we address the alternative therapeutic approach of treatment with mesenchymal stem cells and their potential role in neuroprotection through their ‘calming’ effect on microglia. PMID:24116890

  8. Expression of Inducible Nitric Oxide Synthase (iNOS) in Microglia of the Developing Quail Retina

    PubMed Central

    Sierra, Ana; Navascués, Julio; Cuadros, Miguel A.; Calvente, Ruth; Martín-Oliva, David; Ferrer-Martín, Rosa M.; Martín-Estebané, María; Carrasco, María-Carmen; Marín-Teva, José L.

    2014-01-01

    Inducible nitric oxide synthase (iNOS), which produce large amounts of nitric oxide (NO), is induced in macrophages and microglia in response to inflammatory mediators such as LPS and cytokines. Although iNOS is mainly expressed by microglia that become activated in different pathological and experimental situations, it was recently reported that undifferentiated amoeboid microglia can also express iNOS during normal development. The aim of this study was to investigate the pattern of iNOS expression in microglial cells during normal development and after their activation with LPS by using the quail retina as model. iNOS expression was analyzed by iN