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Sample records for activated microglia play

  1. Activated microglia enhance neurogenesis via trypsinogen secretion.

    PubMed

    Nikolakopoulou, Angeliki M; Dutta, Ranjan; Chen, Zhihong; Miller, Robert H; Trapp, Bruce D

    2013-05-21

    White matter neurons in multiple sclerosis brains are destroyed during demyelination and then replaced in some chronic multiple sclerosis lesions that exhibit a morphologically distinct population of activated microglia [Chang A, et al. (2008) Brain 131(Pt 9):2366-2375]. Here we investigated whether activated microglia secrete factors that promote the generation of neurons from white matter cells. Adult rat brain microglia (resting or activated with lipopolysaccharide) were isolated by flow cytometry and cocultured with neonatal rat optic nerve cells in separate but media-connected chambers. Optic nerve cells cocultured with activated microglia showed a significant increase in the number of cells of neuronal phenotype, identified by neuron-specific class III beta-tubulin (TUJ-1) labeling, compared with cultures with resting microglia. To investigate the possible source of the TUJ-1-positive cells, A2B5-positive oligodendrocyte progenitor cells and A2B5-negative cells were isolated and cocultured with resting and activated microglia. Significantly more TUJ-1-positive cells were generated from A2B5-negative cells (∼70%) than from A2B5-positive cells (~30%). Mass spectrometry analysis of microglia culture media identified protease serine 2 (PRSS2) as a factor secreted by activated, but not resting, microglia. When added to optic nerve cultures, PRSS2 significantly increased neurogenesis, whereas the serine protease inhibitor, secretory leukocyte protease inhibitor, decreased activated microglia-induced neurogenesis. Collectively our data provide evidence that activated microglia increase neurogenesis through secretion of PRSS2.

  2. 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.

  3. 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

  4. Microglia activity modulated by T cell Ig and mucin domain protein 3 (Tim-3).

    PubMed

    Wang, Hong-wei; Zhu, Xin-li; Qin, Li-ming; Qian, Hai-jun; Wang, Yiner

    2015-01-01

    Microglia are the main innate immune cells in the central nervous system that are actively involved in maintaining brain homeostasis and diseases. T cell Ig and mucin domain protein 3 (Tim-3) plays critical roles in both the adaptive and the innate immune system and is an emerging therapeutic target for treatment of various disorders. In the brain Tim-3 is specifically expressed on microglia but its functional role is unclear. Here, we showed that Tim-3 was up-regulated on microglia by ATP or LPS stimulation. Tim-3 activation with antibodies increased microglia expression of TGF-β, TNF-α and IL-1β. Blocking of Tim-3 with antibodies decreased the microglial phagocytosis of apoptotic neurons. Tim-3 blocking alleviated the detrimental effect of microglia on neurons and promoted NG2 cell differentiation in co-cultures. Finally, MAPKs namely ERK1/2 and JNK proteins were phosphorylated upon Tim-3 activation in microglia. Data indicated that Tim-3 modulates microglia activity and regulates the interaction of microglia-neural cells.

  5. 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.

  6. Microglia.

    PubMed

    Perry, V Hugh

    2016-06-01

    The concept of the immunological privilege of the central nervous system (CNS) has had a profound influence on studies of interactions between the immune system and the CNS. At one time there was considerable debate as to whether there were any cells in the CNS of myeloid origin, but we now know that there are a number of populations of myeloid cells in specialized compartments of the CNS and that there is an ongoing bidirectional dialogue between the CNS and the immune system. We briefly review what we know of the different myeloid populations, in particular the microglia: their phenotype and function; their role in CNS homeostasis; and also their role in pathology, focusing on chronic neurodegeneration.

  7. 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.

  8. The role of N-glycan modification of TNFR1 in inflammatory microglia activation.

    PubMed

    Han, Lijian; Zhang, Dongmei; Tao, Tao; Sun, Xiaolei; Liu, Xiaojuan; Zhu, Guizhou; Xu, Zhiwei; Zhu, Liang; Zhang, Yu; Liu, Wangrui; Ke, Kaifu; Shen, Aiguo

    2015-12-01

    Accumulating evidences demonstrated that microglia activation and the autocrine loop of tumor necrosis factor-α (TNFα) greatly contribute to the pathogenesis of several CNS diseases. TNFα exerts its biological effects by interacting with two different receptors: TNF receptor 1 (TNFR1) and TNFR2. The classic proinflammatory activity of TNFα is mainly mediated by TNFR1. In the present study, we found that TNFR1 was modificated by N-glycosylation on Asn151 and Asn202 in microglia. The N-glycosylation of TNFR1 could facilitate its capability of binding to TNFα and further promote the formation of TNFα autocrine loop in microglia stimulated by TNFα, resulting in excessive microglia activation and CNS inflammation. All these processes were related to TNFR1-mediated NF-κB pathways. Elimination of N-glycosylation did not affect the subcellular transportation and cell surface localization of TNFR1, but suppressed ligand-binding affinity. These findings indicated that the N-glycosylation of TNFR1 played an important role during microglia activation in CNS inflammation. By this study, we aimed to provide some valuable experimental evidence for a better understanding of the significance of protein glycosylation in microglia inflammatory activation and CNS disease.

  9. 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

  10. 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.

  11. Neuroprotective potential of molecular hydrogen against perinatal brain injury via suppression of activated microglia.

    PubMed

    Imai, Kenji; Kotani, Tomomi; Tsuda, Hiroyuki; Mano, Yukio; Nakano, Tomoko; Ushida, Takafumi; Li, Hua; Miki, Rika; Sumigama, Seiji; Iwase, Akira; Hirakawa, Akihiro; Ohno, Kinji; Toyokuni, Shinya; Takeuchi, Hideyuki; Mizuno, Tetsuya; Suzumura, Akio; Kikkawa, Fumitaka

    2016-02-01

    Exposure to inflammation in utero is related to perinatal brain injury, which is itself associated with high rates of long-term morbidity and mortality in children. Novel therapeutic interventions during the perinatal period are required to prevent inflammation, but its pathogenesis is incompletely understood. Activated microglia are known to play a central role in brain injury by producing a variety of pro-inflammatory cytokines and releasing oxidative products. The study is aimed to investigate the preventative potential of molecular hydrogen (H2), which is an antioxidant and anti-inflammatory agent without mutagenicity. Pregnant ICR mice were injected with lipopolysaccharide (LPS) intraperitoneally on embryonic day 17 to create a model of perinatal brain injury caused by prenatal inflammation. In this model, the effect of maternal administration of hydrogen water (HW) on pups was also evaluated. The levels of pro-inflammatory cytokines, oxidative damage and activation of microglia were determined in the fetal brains. H2 reduced the LPS-induced expression of pro-inflammatory cytokines, oxidative damage and microglial activation in the fetal brains. Next, we investigated how H2 contributes to neuroprotection, focusing on microglia, using primary cultured microglia and neurons. H2 prevented LPS- or cytokine-induced generation of reactive oxidative species by microglia and reduced LPS-induced microglial neurotoxicity. Finally, we identified several molecules influenced by H2, involved in the process of activating microglia. These results suggested that H2 holds promise for the prevention of inflammation related to perinatal brain injury. PMID:26709014

  12. Neural progenitor cells regulate microglia functions and activity.

    PubMed

    Mosher, Kira I; Andres, Robert H; Fukuhara, Takeshi; Bieri, Gregor; Hasegawa-Moriyama, Maiko; He, Yingbo; Guzman, Raphael; Wyss-Coray, Tony

    2012-11-01

    We found mouse neural progenitor cells (NPCs) to have a secretory protein profile distinct from other brain cells and to modulate microglial activation, proliferation and phagocytosis. NPC-derived vascular endothelial growth factor was necessary and sufficient to exert at least some of these effects in mice. Thus, neural precursor cells may not only be shaped by microglia, but also regulate microglia functions and activity.

  13. 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

  14. Effects of tetramethylpyrazine on microglia activation in spinal cord compression injury of mice.

    PubMed

    Shin, Jung-Won; Moon, Ja-Young; Seong, Ju-Won; Song, Sang-Hoon; Cheong, Young-Jin; Kang, Chulhun; Sohn, Nak-Won

    2013-01-01

    Secondary mechanisms, including inflammation and microglia activation, serve as targets for the development and application of pharmacological strategies in the management of spinal cord injury (SCI). Tetramethylpyrazine (TMP), an active ingredient of Ligusticum wallichii (chuanxiong), has shown anti-inflammatory and neuroprotective effects against SCI. However, it remains uncertain whether the inflammation-suppressive effects of TMP play a modulatory role over microglia activation in SCI. The present study investigated the effects of TMP on microglia activation and pro-inflammatory cytokines in spinal cord compression injury in mice. For a real-time PCR measurement of pro-inflammatory cytokines, SCI was induced in mice by the clip compression method (30 g force, 1 min) and TMP (15 or 30 mg/kg, i.p.) was administered once, 30 minutes before the SCI induction. For immunohistochemistry, TMP (30 mg/kg, i.p.) treatment was given three times during the first 48 hours after the SCI. 30 mg/kg of TMP treatment reduced the up-regulation of TNF-α, IL-1β and COX-2 mRNA in the spinal tissue at four hours after the SCI induction. TMP also significantly attenuated microglia activation and neutrophil infiltration at 48 hours after the SCI induction. In addition, iNOS expression in the spinal tissue was attenuated with TMP treatment. These results suggest that TMP plays a modulatory role in microglia activation and may protect the spinal cord from or potentially delay secondary spinal cord injury. PMID:24228606

  15. 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

  16. Lipopolysaccharide-activated microglia induce death of oligodendrocyte progenitor cells and impede their development.

    PubMed

    Pang, Y; Campbell, L; Zheng, B; Fan, L; Cai, Z; Rhodes, P

    2010-03-17

    Damage to oligodendrocyte (OL) progenitor cells (OPCs) and hypomyelination are two hallmark features of periventricular leukomalacia (PVL), the most common form of brain damage in premature infants. Clinical and animal studies have linked the incidence of PVL to maternal infection/inflammation, and activated microglia have been proposed to play a central role. However, the precise mechanism of how activated microglia adversely affects the survival and development of OPCs is still not clear. Here we demonstrate that lipopolysaccharide (LPS)-activated microglia are deleterious to OPCs, that is, impeding OL lineage progression, reducing the production of myelin basic protein (MBP), and mediating OPC death. We further demonstrate that LPS-activated microglia mediate OPC death by two distinct mechanisms in a time-dependent manner. The early phase of cell damage occurs within 24 h after LPS treatment, which is mediated by nitric oxide (NO)-dependent oxidative damage and is prevented by N(G)-nitro-l-arginine methyl ester (l-NAME), a general inhibitor of nitric oxide synthase. The delayed cell death is evident at 48 h after LPS treatment, is mediated by cytokines, and is prevented by blocking the activity of tumor necrosis factor-alpha (TNF-alpha) and pro-nerve growth factor (proNGF), but not by l-NAME. Furthermore, microglia-derived insulin-like growth factor-1 (IGF-1) and ciliary neurotrophic factor (CNTF) were significantly suppressed by LPS, and exogenous IGF-1 and CNTF synergistically protected OLs from death induced by LPS-treated microglia conditioned medium, indicating that a deficiency in trophic support may also be involved in OL death. Our finding that LPS-activated microglia not only induce two waves of cell death but also greatly impair OL development may shed some light on the mechanisms underlying selective white matter damage and hypomyelination in PVL.

  17. 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

  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. 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

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

    PubMed

    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. 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

  2. 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.

  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. 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

  5. Pinoresinol from the fruits of Forsythia koreana inhibits inflammatory responses in LPS-activated microglia.

    PubMed

    Jung, Hyo Won; Mahesh, Ramalingam; Lee, Jong Gu; Lee, Seung Ho; Kim, Young Shik; Park, Yong-Ki

    2010-08-23

    The activation of microglia plays an important role in a variety of brain disorders by the excessive production of inflammatory mediators such as nitric oxide (NO), prostaglandin E(2) (PGE(2)) and proinflammatory cytokines. We investigated here whether pinoresinol isolated from the fruits of Forsythia koreana Nakai inhibits the inflammatory responses in LPS-activated microglia. Pinoresinol inhibited the production of NO, PGE(2), TNF-alpha, IL-1beta and IL-6 in LPS-activated primary microglia. Also, pinoresinol attenuated mRNA and protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and proinflammatory cytokines in LPS-activation. However, most of these inhibitory effects of pinoresinol have been mediated by extracellular-signal-regulated kinase (ERK) 1/2 mitogen-activated protein kinase (MAPK) phosphorylation and the NF-kappaB dependent. The results suggest that pinoresinol attenuates inflammatory responses of microglia and could be potentially useful in modulation of inflammatory status in brain disorders.

  6. 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.

  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. 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

  9. Greater glucocorticoid receptor activation in hippocampus of aged rats sensitizes microglia.

    PubMed

    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

    2015-03-01

    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 corticosterone levels in the hippocampus, but not in plasma, throughout the daytime (diurnal inactive phase). These elevated hippocampal corticosterone levels were associated with increased hippocampal 11β-hydroxysteroid dehydrogenase type 1 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 Escherichia 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.

  10. 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

  11. 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

  12. 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

  13. Up-regulation of glutamine synthesis in microglia activated with endotoxin.

    PubMed

    Nakajima, Kazuyuki; Kanamatsu, Tomoyuki; Takezawa, Yosuke; Kohsaka, Shinichi

    2015-03-30

    We previously verified that newborn rat brain-derived microglia have the ability to uptake (14)C-glutamate (Glu) through glutamate transporter-1. A given amount of Glu incorporated into microglia was suspected to be metabolized to glutamine (Gln). However, the ability of microglia to do this had not been demonstrated. Thus, in the present study we examined the possibility that primary rat microglia metabolize Glu into Gln. Immunocytochemical and immunoblotting studies indicated that the microglia express glutamine synthetase (GS) protein. As expected from these results, GS activity was actually detected in microglia, although the specific activity was lower than that of astrocytes. Considering this microglial property, it seemed possible that the taken Glu is metabolized to Gln in the cells. To investigate this possibility, we exposed microglia to [(13)C]Glu-containing medium and analyzed the change of Glu to Gln in a nuclear magnetic resonance examination. The results clarified that non-stimulated microglia hardly changed Glu to Gln, but when stimulated with lipopolysaccharide the microglia significantly metabolized [(13)C]Glu to [(13)C]Gln. Microglia were thus, strongly suggested to metabolize Glu to Gln via GS activity when activated in the inflammatory/pathological state of the nervous system. PMID:25681623

  14. Up-regulation of glutamine synthesis in microglia activated with endotoxin.

    PubMed

    Nakajima, Kazuyuki; Kanamatsu, Tomoyuki; Takezawa, Yosuke; Kohsaka, Shinichi

    2015-03-30

    We previously verified that newborn rat brain-derived microglia have the ability to uptake (14)C-glutamate (Glu) through glutamate transporter-1. A given amount of Glu incorporated into microglia was suspected to be metabolized to glutamine (Gln). However, the ability of microglia to do this had not been demonstrated. Thus, in the present study we examined the possibility that primary rat microglia metabolize Glu into Gln. Immunocytochemical and immunoblotting studies indicated that the microglia express glutamine synthetase (GS) protein. As expected from these results, GS activity was actually detected in microglia, although the specific activity was lower than that of astrocytes. Considering this microglial property, it seemed possible that the taken Glu is metabolized to Gln in the cells. To investigate this possibility, we exposed microglia to [(13)C]Glu-containing medium and analyzed the change of Glu to Gln in a nuclear magnetic resonance examination. The results clarified that non-stimulated microglia hardly changed Glu to Gln, but when stimulated with lipopolysaccharide the microglia significantly metabolized [(13)C]Glu to [(13)C]Gln. Microglia were thus, strongly suggested to metabolize Glu to Gln via GS activity when activated in the inflammatory/pathological state of the nervous system.

  15. Activation status of human microglia is dependent on lesion formation stage and remyelination in multiple sclerosis.

    PubMed

    Peferoen, Laura A N; Vogel, Daphne Y S; Ummenthum, Kimberley; Breur, Marjolein; Heijnen, Priscilla D A M; Gerritsen, Wouter H; Peferoen-Baert, Regina M B; van der Valk, Paul; Dijkstra, Christine D; Amor, Sandra

    2015-01-01

    Similar to macrophages, microglia adopt diverse activation states and contribute to repair and tissue damage in multiple sclerosis. Using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, we show that in vitro M1-polarized (proinflammatory) human adult microglia express the distinctive markers CD74, CD40, CD86, and CCR7, whereas M2 (anti-inflammatory) microglia express mannose receptor and the anti-inflammatory cytokine CCL22. The expression of these markers was assessed in clusters of activated microglia in normal-appearing white matter (preactive lesions) and areas of remyelination, representing reparative multiple sclerosis lesions. We show that activated microglia in preactive and remyelinating lesions express CD74, CD40, CD86, and the M2 markers CCL22 and CD209, but not mannose receptor. To examine whether this intermediate microglia profile is static or dynamic and thus susceptible to changes in the microenvironment, we polarized microglia into M1 or M2 phenotype in vitro and then subsequently treated them with the opposing polarization regimen. These studies revealed that expression of CD40, CXCL10, and mannose receptor is dynamic and that microglia, like macrophages, can switch between M1 and M2 phenotypic profiles. Taken together, our data define the differential activation states of microglia during lesion development in multiple sclerosis-affected CNS tissues and underscore the plasticity of human adult microglia in vitro.

  16. Cell type-specific roles for tissue plasminogen activator released by neurons or microglia after excitotoxic injury.

    PubMed

    Siao, Chia-Jen; Fernandez, Susana R; Tsirka, Stella E

    2003-04-15

    Tissue plasminogen activator (tPA) plays important roles in the brain after excitotoxic injury. It is released by both neurons and microglia and mediates neuronal death and microglial activation. Mice lacking tPA are resistant to excitotoxicity and show very limited microglial activation. Activated microglia are neurotoxic in culture, but this phenomenon is not well documented in vivo. To further understand the sequence of events through which tPA mediates microglial activation and neurodegeneration, we have generated mice that exhibit restricted expression of tPA through introduction of tPA transgenes under the control of neuronal- or microglial-specific promoters into tPA-deficient mice. Neither strain of transgenic mice shows abnormal brain morphology or inflammation in the absence of injury, and unilateral intrahippocampal kainate injections into the transgenic mice induced excitotoxicity and microglial activation reminiscent of wild-type mice. However, there are differences in the kinetics of the resulting pathology. The neuronal tPA-expressing mice exhibit accelerated microglial activation compared with wild-type or microglial tPA-expressing mice. However, microglial tPA-expressing mice exhibit greater neurodegeneration. These data suggest a model in which tPA plays different roles after kainate injection depending on whether it is released by neurons or microglia. We propose that tPA, initially secreted from injured neurons, acts as a cytokine to activate microglia at the site of injury. These activated microglia then secrete additional tPA, which promotes extracellular matrix degradation, neurodegeneration, and self-proliferation. We suggest that an approach to attenuate microglia-mediated neuronal death in vivo might be to pharmacologically prevent microglial activation.

  17. Exercise reduces activation of microglia isolated from hippocampus and brain of aged mice

    PubMed Central

    2013-01-01

    Background Aging is associated with low-grade neuroinflammation that includes basal increases in proinflammatory cytokines and expression of inflammatory markers on microglia. Exercise can reduce neuroinflammation following infection in aged animals, but whether exercise modulates basal changes in microglia activation is unknown. Therefore, we evaluated changes in basal microglia activation in cells isolated from the hippocampus and remaining brain following running-wheel access. Methods Adult (4 months) and aged (22 months) male and female BALB/c mice were housed with or without running wheels for 10 weeks. Microglia were isolated from the hippocampus or remaining brain. Flow cytometry was used to determine microglia (CD11b+ and CD45low) that co-labeled with CD86, CD206, and MHC II. Results Aged mice showed a greater proportion of CD86 and MHC II positive microglia. In aged females, access to a running wheel decreased proportion of CD86+ and MHC II+ microglia in the hippocampus whereas aged males in the running group showed a decrease in the proportion of CD86+ microglia in the brain and an increase in the proportion of MHC II+ microglia in hippocampus and brain. Conclusion Overall, these data indicate that running-wheel access modulates microglia activation, but these effects vary by age, sex, and brain region. PMID:24044641

  18. 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.

  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.

  1. 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

  2. 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

  3. 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

  4. 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

  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. Thymosin β4 inhibits microglia activation through microRNA 146a in neonatal rats following hypoxia injury.

    PubMed

    Zhou, Tian; Huang, Yan-xia; Song, Jian-wen; Ma, Qiao-mei

    2015-12-01

    Neuroinflammation mediated by activated microglia plays a pivotal role in the pathogenesis of neurological disorders, including hypoxic injury of the developing brain. Thymosin β4 (Tβ4), the major G-actin-sequestering molecule, has an anti-inflammatory effect and has been used to treat various neurological diseases. However, the effect of Tβ4 on hypoxia-induced microglia activation in the developing brain remains unclear. We investigate here the effect of Tβ4 on microglia activation of neonatal rats after hypoxia exposure. Tβ4 treatment was carried out on 1-day-old rats and BV-2 cells. Tβ4 expression in microglia was determined by quantitative real time-PCR, western blotting, and immunofluorescence staining. Secretion of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and nitric oxide (NO) was assessed by enzyme-linked immunosorbent assay and colorimetric assay. mRNA expression of TNF-α and IL-1β, and microRNA 146a expression was determined by quantitative real time-PCR. We showed that Tβ4 treatment significantly inhibited secretion of inflammatory mediators in the cerebellum of neonatal rats following hypoxia injury. Increased expression of endogenous Tβ4 in microglia was observed both in hypoxic rats and in BV-2 cells. Tβ4 treatment significantly inhibited the expression and secretion of hypoxia-induced TNF-α, IL-1β, and NO. Remarkably, microRNA 146a expression was found to have increased in Tβ4-treated BV-2 cells. We demonstrated the anti-inflammatory effect of Tβ4 in neonatal rats following hypoxic brain injury. More importantly, our data reveal, for the first time, that Tβ4 inhibits microglia activation in vitro. Therefore, this study contributes to understanding the role and mechanism of Tβ4 function in central nervous system diseases.

  7. Endotoxin-Induced Systemic Inflammation Activates Microglia: [11C]PBR28 Positron Emission Tomography in Nonhuman Primates

    PubMed Central

    Hannestad, Jonas; Gallezot, Jean-Dominique; Schafbauer, Thomas; Lim, Keunpoong; Kloczynski, Tracy; Morris, Evan D.; Carson, Richard E; Ding, Yu-Shin; Cosgrove, Kelly

    2013-01-01

    Microglia play an essential role in many brain diseases. Microglia are activated by local tissue damage or inflammation, but systemic inflammation can also activate microglia. An important clinical question is whether the effects of systemic inflammation on microglia mediates the deleterious effects of systemic inflammation in diseases such as Alzheimer's dementia, multiple sclerosis, and stroke. Positron Emission Tomography (PET) imaging with ligands that bind to Translocator Protein (TSPO) can be used to detect activated microglia. The aim of this study was to evaluate whether the effect of systemic inflammation on microglia could be measured with PET imaging in nonhuman primates, using the TSPO ligand [11C]PBR28. Methods Six female baboons (Papio anubis) were scanned before and at 1 h and/or 4h and/or 22h after intravenous administration of E. coli lipopolysaccharide (LPS; 0.1 mg/kg), which induces systemic inflammation. Regional time-activity data from regions of interest (ROIs) were fitted to the two-tissue compartmental model, using the metabolite-corrected arterial plasma curve as input function. Total volume of distribution (VT) of [11C]PBR28 was used as a measure of total ligand binding. The primary outcome was change in VT from baseline. Serum levels of tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8) were used to assess correlations between systemic inflammation and microglial activation. In one baboon, immunohistochemistry was used to identify cells expressing TSPO. Results LPS administration increased [11C]PBR28 binding (F(3,6)=5.1, p=.043) with a 29±16 % increase at 1h (n = 4) and a 62±34% increase at 4h (n = 3) post-LPS. There was a positive correlation between serum IL-1β and IL-6 levels and the increase in [11C]PBR28 binding. TSPO immunoreactivity occurred almost exclusively in microglia and rarely in astrocytes. Conclusion In the nonhuman-primate brain, LPS-induced systemic

  8. A three-dimensional collagen construct to model lipopolysaccharide-induced activation of BV2 microglia

    PubMed Central

    2014-01-01

    Background We report a novel method of culturing microglia in three dimension (3D) using collagen as a substrate. By culturing microglia within a matrix, we aim to emulate the physical state of microglia embedded within parenchyma. Methods BV2 microglia cell suspensions were prepared with type I collagen and cast into culture plates. To characterise the BV2 microglia cultured in 3D, the cultures were evaluated for their viability, cell morphology and response to lipopolysaccharide (LPS) activation. Conventional monolayer cultures (grown on uncoated and collagen-coated polystyrene) were set up concurrently for comparison. Results BV2 microglia in 3D collagen matrices were viable at 48 hrs of culture and exhibit a ramified morphology with multiplanar cytoplasmic projections. Following stimulation with 1 μg/ml LPS, microglia cultured in 3D collagen gels increase their expression of nitric oxide (NO) and CD40, indicating their capacity to become activated within the matrix. Up to 97.8% of BV2 microglia grown in 3D cultures gained CD40 positivity in response to LPS, compared to approximately 60% of cells grown in a monolayer (P < .05). BV2 microglia in 3D collagen gels also showed increased mRNA and protein expression of inflammatory cytokines IL-6, TNF-α and the chemoattractant MCP-1 following LPS stimulation. Conclusions In summary, BV2 microglia cultured in 3D collagen hydrogels exhibit multiplanar cytoplasmic projections and undergo a characteristic and robust activation response to LPS. This culture system is accessible to a wide range of analyses and provides a useful new in vitro tool for research into microglial activation. PMID:25074682

  9. Involvement of Microglia Activation in the Lead Induced Long-Term Potentiation Impairment

    PubMed Central

    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. 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

  11. 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.

  12. Somatostatin modulates insulin-degrading-enzyme metabolism: implications for the regulation of microglia activity in AD.

    PubMed

    Tundo, Grazia; Ciaccio, Chiara; Sbardella, Diego; Boraso, Mariaserena; Viviani, Barbara; Coletta, Massimiliano; Marini, Stefano

    2012-01-01

    The deposition of β-amyloid (Aβ) into senile plaques and the impairment of somatostatin-mediated neurotransmission are key pathological events in the onset of Alzheimer's disease (AD). Insulin-degrading-enzyme (IDE) is one of the main extracellular protease targeting Aβ, and thus it represents an interesting pharmacological target for AD therapy. We show that the active form of somatostatin-14 regulates IDE activity by affecting its expression and secretion in microglia cells. A similar effect can also be observed when adding octreotide. Following a previous observation where somatostatin directly interacts with IDE, here we demonstrate that somatostatin regulates Aβ catabolism by modulating IDE proteolytic activity in IDE gene-silencing experiments. As a whole, these data indicate the relevant role played by somatostatin and, potentially, by analogue octreotide, in preventing Aβ accumulation by partially restoring IDE activity.

  13. 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

  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.

  15. Progranulin promotes activation of microglia/macrophage after pilocarpine-induced status epilepticus.

    PubMed

    Zhu, Shanshan; Tai, Chao; Petkau, Terri L; Zhang, Si; Liao, Chengyong; Dong, Zhifang; Wen, Wendy; Chang, Qing; Tian Wang, Yu; MacVicar, Brian A; Leavitt, Blair R; Jia, William; Cynader, Max S

    2013-09-12

    Progranulin (PGRN) haploinsufficiency accounts for up to 10% of frontotemporal lobe dementia. PGRN has also been implicated in neuroinflammation in acute and chronic neurological disorders. Here we report that both protein and mRNA levels of cortical and hippocampal PGRN are significantly enhanced following pilocarpine-induced status epilepticus. We also identify intense PGRN immunoreactivity that colocalizes with CD11b in seizure-induced animals, suggesting that PGRN elevation occurs primarily in activated microglia and macrophages. To test the role of PGRN in activation of microglia/macrophages, we apply recombinant PGRN protein directly into the hippocampal formation, and observe no change in the number of CD11b(+) microglia/macrophages in the dentate gyrus. However, with pilocarpine-induced status epilepticus, PGRN application significantly increases the number of CD11b(+) microglia/macrophages in the dentate gyrus, without affecting the extent of hilar cell death. In addition, the number of CD11b(+) microglia/macrophages induced by status epilepticus is not significantly different between PGRN knockout mice and wildtype. Our findings suggest that status epilepticus induces PGRN expression, and that PGRN potentiates but is not required for seizure-induced microglia/macrophage activation.

  16. Neural progenitor cell apoptosis and differentiation were affected by activated microglia in spinal cord slice culture.

    PubMed

    Liu, Xuqing; Chu, Tak-Ho; Su, Huanxing; Guo, Anchen; Wu, Wutian

    2014-03-01

    Neural progenitor cell (NPC) transplantation offers great potential to treat spinal cord injury (SCI). NPCs may replace lost neurons or oligodendrocytes and act as a source of neurotrophic factors to support survival of remaining cells. However, their efficiency was limited by poor survival after transplantation, and they tended more to differentiate into astrocytes, but not neurons and oligodendrocytes. This study investigated whether activated microglia is a factor that contributes to this phenomenon. Organotypic spinal cord slice (SCS) culture was used to mimic the local environment after SCI, and NPCs were co-cultured with them to share the culture medium. After specific depletion of microglia in the SCSs with clodronate loaded liposome, the apoptotic rate of NPCs decreased, more NPCs differentiated into neurons, and glial differentiation was impaired. This suggested that microglia may impair NPC survival, and neuronal differentiation, but improve astrocyte differentiation. In NPC transplantation strategy for SCI, microglia would be manipulated to improve the survival and neuronal differentiation of NPCs.

  17. 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

  18. 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

  19. 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

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

    PubMed

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

    2016-01-01

    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.

  1. MicroRNA-125b regulates microglia activation and motor neuron death in ALS

    PubMed Central

    Parisi, C; Napoli, G; Amadio, S; Spalloni, A; Apolloni, S; Longone, P; Volonté, C

    2016-01-01

    Understanding the means by which microglia self-regulate the neuroinflammatory response helps modulating their reaction during neurodegeneration. In amyotrophic lateral sclerosis (ALS), classical NF-κB pathway is related to persistent microglia activation and motor neuron injury; however, mechanisms of negative control of NF-κB activity remain unexplored. One of the major players in the termination of classical NF-κB pathway is the ubiquitin-editing enzyme A20, which has recognized anti-inflammatory functions. Lately, microRNAs are emerging as potent fine-tuners of neuroinflammation and reported to be regulated in ALS, for instance, by purinergic P2X7 receptor activation. In this work, we uncover an interplay between miR-125b and A20 protein in the modulation of classical NF-κB signaling in microglia. In particular, we establish the existence of a pathological circuit in which termination of A20 function by miR-125b strengthens and prolongs the noxious P2X7 receptor-dependent activation of NF-κB in microglia, with deleterious consequences on motor neurons. We prove that, by restoring A20 levels, miR-125b inhibition then sustains motor neuron survival. These results introduce miR-125b as a key mediator of microglia dynamics in ALS. PMID:26794445

  2. Distinct activation profiles in microglia of different ages: a systematic study in isolated embryonic to aged microglial cultures.

    PubMed

    Lai, A Y; Dibal, C D; Armitage, G A; Winship, I R; Todd, K G

    2013-12-19

    Microglia have been implicated in disease progression for several age-related brain disorders. However, while microglia's contribution to the progression of these disorders is accepted, the effect of aging on their endogenous cellular characteristics has received limited attention. In fact, a comprehensive study of how the structure and function of microglia changes as a function of developmental age has yet to be performed. Here, we describe the functional response characteristics of primary microglial cultures prepared from embryonic, neonatal (Neo), 2-3month-old, 6-8month-old, 9-11month-old, and 13-15month-old rats. Microglial morphology, glutamate (GLU) uptake, and release of trophic and inflammatory factors were assessed under basal conditions and in microglia activated with adenosine 5'-triphosphate (ATP) or lipopolysaccharide. We found that microglia from different age groups were both morphologically and functionally distinct. Upon activation by ATP, Neo microglia were the most reactive, upregulating nitric oxide, tumor necrosis factor-α, and brain-derived neurotrophic factor release as well as GLU uptake. This upregulation translated into neurotoxicity in microglia-neuron co-cultures that were not observed with microglia of different developmental ages. Interestingly, 13-15month-old microglia exhibited similar activation profiles to Neo microglia, whereas microglia from younger adults and embryos were activated less by ATP. Our data also identify age-dependent differences in purinergic receptor subtype expression that contribute to the regulation of neuronal survival. Combined, our data demonstrate that microglial activation and purinergic receptor profiles vary non-linearly with developmental age, a potentially important finding for studies examining the role of microglia in neurodegenerative disorders.

  3. Microvesicles released from microglia stimulate synaptic activity via enhanced sphingolipid metabolism

    PubMed Central

    Antonucci, Flavia; Turola, Elena; Riganti, Loredana; Caleo, Matteo; Gabrielli, Martina; Perrotta, Cristiana; Novellino, Luisa; Clementi, Emilio; Giussani, Paola; Viani, Paola; Matteoli, Michela; Verderio, Claudia

    2012-01-01

    Microvesicles (MVs) released into the brain microenvironment are emerging as a novel way of cell-to-cell communication. We have recently shown that microglia, the immune cells of the brain, shed MVs upon activation but their possible role in microglia-to-neuron communication has never been explored. To investigate whether MVs affect neurotransmission, we analysed spontaneous release of glutamate in neurons exposed to MVs and found a dose-dependent increase in miniature excitatory postsynaptic current (mEPSC) frequency without changes in mEPSC amplitude. Paired-pulse recording analysis of evoked neurotransmission showed that MVs mainly act at the presynaptic site, by increasing release probability. In line with the enhancement of excitatory transmission in vitro, injection of MVs into the rat visual cortex caused an acute increase in the amplitude of field potentials evoked by visual stimuli. Stimulation of synaptic activity occurred via enhanced sphingolipid metabolism. Indeed, MVs promoted ceramide and sphingosine production in neurons, while the increase of excitatory transmission induced by MVs was prevented by pharmacological or genetic inhibition of sphingosine synthesis. These data identify microglia-derived MVs as a new mechanism by which microglia influence synaptic activity and highlight the involvement of neuronal sphingosine in this microglia-to-neuron signalling pathway. PMID:22246184

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

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

    PubMed

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

    2014-07-01

    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 of 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 have 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 (0.3 g/L water) and high caffeine (1.0 g/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.

  11. 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

  12. 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

  13. 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

  14. Microglia activated by IL-4 or IFN-gamma differentially induce neurogenesis and oligodendrogenesis from adult stem/progenitor cells.

    PubMed

    Butovsky, Oleg; Ziv, Yaniv; Schwartz, Adi; Landa, Gennady; Talpalar, Adolfo E; Pluchino, Stefano; Martino, Gianvito; Schwartz, Michal

    2006-01-01

    Cell renewal in the adult central nervous system (CNS) is limited, and is blocked in inflammatory brain conditions. We show that both neurogenesis and oligodendrogenesis of adult neural progenitor cells in mice are blocked by inflammation-associated (endotoxin-activated) microglia, but induced by microglia activated by cytokines (IL-4 or low level of IFN-gamma) associated with T-helper cells. Blockage was correlated with up-regulation of microglial production of tumor necrosis factor-alpha. The effect induced by IL-4-activated microglia was mediated, at least in part, by insulin-like growth factor-I. The IL-4-activated microglia showed a bias towards oligodendrogenesis whereas the IFN-gamma-activated microglia showed a bias towards neurogenesis. It thus appears that microglial phenotype critically affects their ability to support or impair cell renewal from adult stem cell.

  15. Dual role of superoxide dismutase 2 induced in activated microglia: oxidative stress tolerance and convergence of inflammatory responses.

    PubMed

    Ishihara, Yasuhiro; Takemoto, Takuya; Itoh, Kouichi; Ishida, Atsuhiko; Yamazaki, Takeshi

    2015-09-11

    Microglia are activated quickly in response to external pathogens or cell debris and clear these substances via the inflammatory response. However, excessive activation of microglia can be harmful to host cells due to the increased production of reactive oxygen species and proinflammatory cytokines. Superoxide dismutase 2 (SOD2) is reportedly induced under various inflammatory conditions in the central nervous system. We herein demonstrated that activated microglia strongly express SOD2 and examined the role of SOD2, focusing on regulation of the microglial activity and the susceptibility of microglia to oxidative stress. When rat primary microglia were treated with LPS, poly(I:C), peptidoglycan, or CpG oligodeoxynucleotide, respectively, the mRNA and protein levels of SOD2 largely increased. However, an increased expression of SOD2 was not detected in the primary neurons or astrocytes, indicating that SOD2 is specifically induced in microglia under inflammatory conditions. The activated microglia showed high tolerance to oxidative stress, whereas SOD2 knockdown conferred vulnerability to oxidative stress. Interestingly, the production of proinflammatory cytokines was increased in the activated microglia treated with SOD2 siRNA compared with that observed in the control siRNA-treated cells. Pretreatment with NADPH oxidase inhibitors, diphenylene iodonium and apocynin, decreased in not only reactive oxygen species generation but also the proinflammatory cytokine expression. Notably, SOD2 knockdown largely potentiated the nuclear factor κB activity in the activated microglia. Taken together, increased SOD2 conferred tolerance to oxidative stress in the microglia and decreased proinflammatory cytokine production by attenuating the nuclear factor κB activity. Therefore, SOD2 might regulate neuroinflammation by controlling the microglial activities.

  16. Electron transport chain inhibitors induce microglia activation through enhancing mitochondrial reactive oxygen species production.

    PubMed

    Ye, Junli; Jiang, Zhongxin; Chen, Xuehong; Liu, Mengyang; Li, Jing; Liu, Na

    2016-01-15

    Reactive oxygen species (ROS) are believed to be mediators of excessive microglial activation, yet the resources and mechanism are not fully understood. Here we stimulated murine microglial BV-2 cells and primary microglial cells with different inhibitors of electron transport chain (ETC), rotenone, thenoyltrifluoroacetone (TTFA), antimycin A, and NaN3 to induce mitochondrial ROS production and we observed the role of mitochondrial ROS in microglial activation. Our results showed that ETC inhibitors resulted in significant changes in cell viability, microglial morphology, cell cycle arrest and mitochondrial ROS production in a dose-dependent manner in both primary cultural microglia and BV-2 cell lines. Moreover, ETC inhibitors, especially rotenone and antimycin A stimulated secretion of interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) by microglia with marked activation of mitogen-activated proteinkinases (MAPKs) and nuclear factor κB (NF-κB), which could be blocked by specific inhibitors of MAPK and NF-κB and mitochondrial antioxidants, Mito-TEMPO. Taken together, our results demonstrated that inhibition of mitochondrial respiratory chain in microglia led to production of mitochondrial ROS and therefore may activate MAPK/NF-кB dependent inflammatory cytokines release in microglia, which indicated that mitochondrial-derived ROS were contributed to microglial activation.

  17. Immune activation promotes depression one month after diffuse brain injury: a role for primed microglia

    PubMed Central

    Fenn, Ashley M.; Gensel, John C.; Huang, Yan; Popovich, Phillip G.; Lifshitz, Jonathan; Godbout, Jonathan P.

    2014-01-01

    Background Traumatic brain injury (TBI) is associated with a higher incidence of depression. The majority of individuals who suffer a TBI are juveniles and young adults and thus, the risk of a lifetime of depressive complications is a significant concern. The etiology of increased TBI-associated depression is unclear, but may be inflammatory-related with increased brain sensitivity to secondary inflammatory challenges (e.g., stressors, infection, and injury). Methods Adult male BALB/c mice received a sham (n=52) or midline fluid percussion injury (TBI) (n=57). Neuroinflammation, motor coordination (rotarod), and depressive behaviors (social withdrawal, immobility in the tail suspension test, and anhedonia) were assessed 4 h, 24 h, 72 h, 7 d, or 30 d later. Moreover, 30 d after surgery, sham and TBI mice received a peripheral injection of saline or lipopolysaccharide (LPS) and microglia activation and behavior were determined. Results Diffuse TBI caused inflammation, peripheral cell recruitment, and microglia activation immediately after injury coinciding with motor coordination deficits. These transient events resolved within 7 d. Nonetheless, 30 days post-TBI a population of de-ramified and major histocompatibility complex (MHC)II+ (primed) microglia were detected. After a peripheral LPS challenge, the inflammatory cytokine response in primed microglia of TBI mice was exaggerated compared to microglia of controls. Furthermore, this LPS-induced microglia reactivity 30 d after TBI was associated with the onset of depressive-like behavior. Conclusions These results implicate a primed and immune-reactive microglial population as a possible triggering mechanism for the development of depressive complications after TBI. PMID:24289885

  18. Activated microglia impairs neuroglial interaction by opening Cx43 hemichannels in hippocampal astrocytes.

    PubMed

    Abudara, Verónica; Roux, Lisa; Dallérac, Glenn; Matias, Isabelle; Dulong, Jérôme; Mothet, Jean Pierre; Rouach, Nathalie; Giaume, Christian

    2015-05-01

    Glia plays an active role in neuronal functions and dysfunctions, some of which depend on the expression of astrocyte connexins, the gap junction channel and hemichannel proteins. Under neuroinflammation triggered by the endotoxin lipopolysacharide (LPS), microglia is primary stimulated and releases proinflammatory agents affecting astrocytes and neurons. Here, we investigate the effects of such microglial activation on astrocyte connexin-based channel functions and their consequences on synaptic activity in an ex vivo model. We found that LPS induces astroglial hemichannel opening in acute hippocampal slices while no change is observed in gap junctional communication. Based on pharmacological and genetic approaches we found that the LPS-induced hemichannel opening is mainly due to Cx43 hemichannel activity. This process primarily requires a microglial stimulation resulting in the release of at least two proinflammatory cytokines, IL-1β and TNF-α. Consequences of the hemichannel-mediated increase in membrane permeability are a calcium rise in astrocytes and an enhanced glutamate release associated to a reduction in excitatory synaptic activity of pyramidal neurons in response to Schaffer's collateral stimulation. As a whole our findings point out astroglial hemichannels as key determinants of the impairment of synaptic transmission during neuroinflammation.

  19. Pleiotrophin promotes microglia proliferation and secretion of neurotrophic factors by activating extracellular signal-regulated kinase 1/2 pathway.

    PubMed

    Miao, Jiayin; Ding, Minghui; Zhang, Aiwu; Xiao, Zijian; Qi, Weiwei; Luo, Ning; Di, Wei; Tao, Yuqian; Fang, Yannan

    2012-12-01

    Pleiotrophin (PTN) is an effective neuroprotective factor and its expression is strikingly increased in microglia after ischemia/reperfusion injury. However, whether PTN could provide neurotrophic support to neurons by regulating microglia function is not clear. In this study, we demonstrated that the expression of PTN was induced in microglia after oxygen-glucose deprivation/reperfusion. PTN promoted the proliferation of microglia by enhancing the G1 to S phase transition. PTN also stimulated the secretion of brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and nerve growth factor (NGF) in microglia, but did not upregulate the expression of proinflammatory factors such as TNF-α, IL-1β and iNOS. Mechanistically, we found that PTN increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 in microglia in both concentration-dependent and time-dependent manners. In addition, ERK1/2 inhibitor U0126 abolished the proliferation and G1 to S phase transition of microglia stimulated by PTN, and inhibited the production of BDNF, CNTF and NGF induced by PTN. In conclusion, our results demonstrated that PTN-ERK1/2 pathway plays important role in regulating microglia growth and secretion of neurotrophic factors. These findings provide new insight into the neuroprotective role of PTN and suggest that PTN is a new target for therapeutic intervention of stroke.

  20. Macroglia-microglia interactions via TSPO signaling regulates microglial activation in the mouse retina.

    PubMed

    Wang, Minhua; Wang, Xu; Zhao, Lian; Ma, Wenxin; Rodriguez, Ignacio R; Fariss, Robert N; Wong, Wai T

    2014-03-01

    Chronic retinal inflammation in the form of activated microglia and macrophages are implicated in the etiology of neurodegenerative diseases of the retina, including age-related macular degeneration, diabetic retinopathy, and glaucoma. However, molecular biomarkers and targeted therapies for immune cell activation in these disorders are currently lacking. To address this, we investigated the involvement and role of translocator protein (TSPO), a biomarker of microglial and astrocyte gliosis in brain degeneration, in the context of retinal inflammation. Here, we find that TSPO is acutely and specifically upregulated in retinal microglia in separate mouse models of retinal inflammation and injury. Concomitantly, its endogenous ligand, diazepam-binding inhibitor (DBI), is upregulated in the macroglia of the mouse retina such as astrocytes and Müller cells. In addition, we discover that TSPO-mediated signaling in microglia via DBI-derived ligands negatively regulates features of microglial activation, including reactive oxygen species production, TNF-α expression and secretion, and microglial proliferation. The inducibility and effects of DBI-TSPO signaling in the retina reveal a mechanism of coordinated macroglia-microglia interactions, the function of which is to limit the magnitude of inflammatory responses after their initiation, facilitating a return to baseline quiescence. Our results indicate that TSPO is a promising molecular marker for imaging inflammatory cell activation in the retina and highlight DBI-TSPO signaling as a potential target for immodulatory therapies.

  1. 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

  2. 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.

  3. 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

  4. Classical and Alternative Activation of Cyanobacterium Oscillatoria sp. Lipopolysaccharide-Treated Rat Microglia in vitro.

    PubMed

    Mayer, Alejandro M S; Murphy, Joseph; MacAdam, David; Osterbauer, Christopher; Baseer, Imaan; Hall, Mary L; Feher, Domonkos; Williams, Phillip

    2016-02-01

    The purpose of this investigation was to test the hypothesis that an in vitro exposure to cyanobacterium Oscillatoria sp. Lipopolysaccharide (LPS) might result in classical and alternative activation of rat neonatal microglia. Using Escherichia coli LPS-primed microglia as a positive control, this study revealed that treatment of rat microglia with Oscillatoria sp. LPS for 17 h in vitro resulted in both classical and alternative activation as well as concomitant pro-inflammatory and anti-inflammatory mediator release, in a concentration-dependent manner: (1) treatment with 0.1-10 000 ng/ml Oscillatoria sp. LPS resulted in minimal lactic dehydrogenase (LDH) release, induced concentration-dependent and statistically significant O2 (-) generation, matrix metalloproteinase-9 (MMP-9) release, generation of the cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and the chemokines macrophage inflammatory protein-2 (MIP-2/CXCL2), interferon γ-induced protein 10 kDa (IP-10/CXCL-10), (MIP-1α/CCL3), monocyte chemotactic protein-1 (MCP-1/CCL2), regulated on activation, normal T cell expressed and secreted (RANTES/CCL5), and the alternative activation cytokine IL-10; (3) in contrast, treatment with 100 000 ng/ml Oscillatoria sp. LPS appeared to damage the microglia cell membrane, because it resulted in minimal O2 (-) generation, statistically significant LDH release, and a decrease in the generation of all the cytokines and chemokines investigated, with the exception of IL-1α and cytokine-induced neutrophil chemoattractant 1 (CINC-1/CXCL1) generation, which was increased. Thus, our results provide experimental support for our working hypothesis, namely that Oscillatoria sp. LPS induces classical and alternative activation of rat brain microglia in vitro in a concentration-dependent manner, namely 0.1-10 000 ng/ml Oscillatoria sp. LPS, when microglia cells were shown to be viable. Furthermore, should cyanobacterium Oscillatoria sp. LPS gain

  5. [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

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

    PubMed Central

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

    2011-01-01

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

  7. Activation and function of murine primary microglia in the absence of the prion protein.

    PubMed

    Pinheiro, Lívia P; Linden, Rafael; Mariante, Rafael M

    2015-09-15

    The prion protein (PrP(C)) is predominantly expressed in the nervous and immune systems and is involved in relevant cell signaling. Microglia participate in neuroimmune interactions, and their regulatory mechanisms are critical for both health and disease. Despite recent reports with a microglial cell line, little is known about the relevance of PrP(C) in brain microglia. We investigated the role of PrP(C) in mouse primary microglia, and found no differences between wild type and Prnp-null cells in cell morphology or the expression of a microglial marker. Translocation of NF-κB to the nucleus also did not differ, nor did cytokine production. The levels of iNOS were also similar and, finally, microglia of either genotype showed no differences in either rates of phagocytosis or migration, even following activation. Thus, functional roles of PrP(C) in primary microglial cells are - if present - much more subtle than in transformed microglial cell lines.

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

    SciTech Connect

    Lee, Jongseok; Shin, Sooan; Teng, C.-H.; Hong, Suk Jin; Kim, Kwang Sik . E-mail: kwangkim@jhmi.edu

    2005-09-02

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

  9. Toll-like receptor 2-mediated alternative activation of microglia is protective after spinal cord injury.

    PubMed

    Stirling, David P; Cummins, Karen; Mishra, Manoj; Teo, Wulin; Yong, V Wee; Stys, Peter

    2014-03-01

    Improving neurological outcome after spinal cord injury is a major clinical challenge because axons, once severed, do not regenerate but 'dieback' from the lesion site. Although microglia, the immunocompetent cells of the brain and spinal cord respond rapidly to spinal cord injury, their role in subsequent injury or repair remains unclear. To assess the role of microglia in spinal cord white matter injury we used time-lapse two-photon and spectral confocal imaging of green fluorescent protein-labelled microglia, yellow fluorescent protein-labelled axons, and Nile Red-labelled myelin of living murine spinal cord and revealed dynamic changes in white matter elements after laser-induced spinal cord injury in real time. Importantly, our model of acute axonal injury closely mimics the axonopathy described in well-characterized clinically relevant models of spinal cord injury including contusive-, compressive- and transection-based models. Time-lapse recordings revealed that microglia were associated with some acute pathophysiological changes in axons and myelin acutely after laser-induced spinal cord injury. These pathophysiological changes included myelin and axonal spheroid formation, spectral shifts in Nile Red emission spectra in axonal endbulbs detected with spectral microscopy, and 'bystander' degeneration of axons that survived the initial injury, but then succumbed to secondary degeneration. Surprisingly, modulation of microglial-mediated release of neurotoxic molecules failed to protect axons and myelin. In contrast, sterile stimulation of microglia with the specific toll-like receptor 2 agonist Pam2CSK4 robustly increased the microglial response to ablation, reduced secondary degeneration of central myelinated fibres, and induced an alternative (mixed M1:M2) microglial activation profile. Conversely, Tlr2 knock out: Thy1 yellow fluorescent protein double transgenic mice experienced greater axonal dieback than littermate controls. Thus, promoting an alternative

  10. Structure-activity relationship study of dibenzocyclooctadiene lignans isolated from Schisandra chinensis on lipopolysaccharide-induced microglia activation.

    PubMed

    Hu, Di; Han, Na; Yao, Xuechun; Liu, Zhihui; Wang, Yu; Yang, Jingyu; Yin, Jun

    2014-06-01

    To explore the relationship of the dibenzocyclooctadiene lignans from Schisandra chinensis to their anti-inflammatory activities, series of dibenzocyclooctadiene lignans were isolated and assessed by testing their inhibitory effects on nitric oxide production in lipopolysaccharide-induced BV2 mouse microglia. It was found, for the first time, that dibenzocyclooctadiene lignans which have S-biphenyl and methylenedioxy groups strongly inhibited LPS-induced microglia activation. The methoxy group on the cyclooctadiene introduced more effectiveness, but the presence of an acetyl group on the cyclooctadiene or hydroxyl group on C-7 decreased the inhibitory activity.

  11. C/EBPβ expression in activated microglia in amyotrophic lateral sclerosis.

    PubMed

    Valente, Tony; Mancera, Pilar; Tusell, Josep M; Serratosa, Joan; Saura, Josep

    2012-09-01

    Neuroinflammation is thought to play a pathogenic role in many neurodegenerative disorders including amyotrophic lateral sclerosis (ALS). In this study we demonstrate that the expression of nitric oxide (NO) synthase-2 (NOS2), and cyclooxygenase (COX)-2 induced by lipopolysaccharide (LPS) with interferon-γ is higher in microglial-enriched cultures from G93A-SOD1 mice, an ALS animal model, than from wild type mice. The levels of CCAAT/enhancer binding protein β (C/EBPβ), a transcription factor that regulates proinflammatory gene expression, are also upregulated in activated G93A-SOD1 microglial cells. In vivo, systemic lipopolysaccharide also induces an exacerbated neuroinflammatory response in G93A-SOD1 mice versus wild type mice, with increased expression of glial fibrillary acidic protein (GFAP), CD11b, nitric oxide synthase-2, cyclooxygenase-2, proinflammatory cytokines, and C/EBPβ. Finally, we report that C/EBPβ is expressed by microglia in the spinal cord of ALS patients. This is the first demonstration to our knowledge of microglial C/EBPβ expression in human disease. Altogether these findings indicate that G93A-SOD1 expression results in an exacerbated pattern of neuroinflammation and suggest that C/EBPβ is a candidate to regulate the expression of potentially neurotoxic genes in microglial cells in ALS.

  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. A novel technique for morphometric quantification of subarachnoid hemorrhage-induced microglia activation

    PubMed Central

    Plog, Benjamin A.; Moll, Katherine M.; Kang, Hongyi; Iliff, Jeffrey J.; Nedergaard, Maiken; Vates, G. Edward

    2014-01-01

    Background Subarachnoid hemorrhage (SAH) is a neurologic catastrophe and poor outcome is typically attributed to vasospasm; however, there is also evidence that SAH causes a pro-inflammatory state and these two phenomena may be interrelated. SAH causes activation of microglia, but the time course and degree of microglial activation after SAH and its link to poor patient outcome and vasospasm remains unknown. New Method Transgenic mice expressing eGFP under the control of the CX3CR1 locus, in which microglia are endogenously fluorescent, were randomly assigned to control or SAH groups. Immunohistochemistry for CD-68 and CD-31 was performed at different time points after SAH. Using confocal microscopy and MatLab software, we have developed a novel technique to detect and quantify the stages of microglial activation and return to quiescence using an automated computerized morphometric analysis. Results We detected a statistically significant decrease in microglial process complexity 2 and 7 days following SAH. In addition, we detected a statistically significant increase in microglial domain volume 1 day following SAH; however, microglial domain volume returned to baseline by 2 days. Comparison with Existing Method Most techniques for microglia assessment are qualitative, not quantitative, and are therefore inadequate to address the effects of anti-inflammatory drug treatment or other therapies after SAH. Conclusions Using novel image analysis techniques we were able to reproducibly quantify activation of microglia following SAH, which will improve our ability to study the biology of microglial activation, and may ultimately improve management of disease progression and response to therapies directed at microglial activation. PMID:24735531

  14. 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.

  15. Lipopolysaccharide preconditioning facilitates M2 activation of resident microglia after spinal cord injury.

    PubMed

    Hayakawa, Kentaro; Okazaki, Rentaro; Morioka, Kazuhito; Nakamura, Kozo; Tanaka, Sakae; Ogata, Toru

    2014-12-01

    The inflammatory response following spinal cord injury (SCI) has both harmful and beneficial effects; however, it can be modulated for therapeutic benefit. Endotoxin/lipopolysaccharide (LPS) preconditioning, a well-established method for modifying the immune reaction, has been shown to attenuate damage induced by stroke and brain trauma in rodent models. Although such effects likely are conveyed by tissue-repairing functions of the inflammatory response, the mechanisms that control the effects have not yet been elucidated. The present study preconditioned C57BL6/J mice with 0.05 mg/kg of LPS 48 hr before inducing contusion SCI to investigate the effect of LPS preconditioning on the activation of macrophages/microglia. We found that LPS preconditioning promotes the polarization of M1/M2 macrophages/microglia toward an M2 phenotype in the injured spinal cord on quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical analyses. Flow cytometric analyses reveal that LPS preconditioning facilitates M2 activation in resident microglia but not in infiltrating macrophages. Augmented M2 activation was accompanied by vascularization around the injured lesion, resulting in improvement in both tissue reorganization and functional recovery. Furthermore, we found that M2 activation induced by LPS preconditioning is regulated by interleukin-10 gene expression, which was preceded by the transcriptional activation of interferon regulatory factor (IRF)-3, as demonstrated by Western blotting and an IRF-3 binding assay. Altogether, our findings demonstrate that LPS preconditioning has a therapeutic effect on SCI through the modulation of M1/M2 polarization of resident microglia. The present study suggests that controlling M1/M2 polarization through endotoxin signal transduction could become a promising therapeutic strategy for various central nervous system diseases. © 2014 Wiley Periodicals, Inc.

  16. A Nurr1/CoREST transrepression pathway attenuates neurotoxic inflammation in activated microglia and astrocytes

    PubMed Central

    Saijo, Kaoru; Winner, Beate; Carson, Christian T.; Collier, Jana G.; Boyer, Leah; Rosenfeld, Michael G.; Gage, Fred H.; Glass, Christopher K.

    2009-01-01

    Nurr1, an orphan nuclear receptor, plays an essential role in the generation and maintenance of dopaminergic neurons in the brain. Rare mutations in Nurr1 are associated with familial Parkinson’s disease, but the underlying basis for this relationship has not been established. Here, we demonstrate that Nurr1 unexpectedly functions to inhibit expression of pro-inflammatory neurotoxic mediators in both microglia and astrocytes. Reduced Nurr1 expression results in exaggerated inflammatory responses in microglia that are further amplified by astrocytes, leading to the production of factors that cause death of tyrosine hydroxylase-expressing neurons. Nurr1 exerts anti-inflammatory effects by docking to NF-κB-p65 on target inflammatory gene promoters in a signal-dependent manner. Subsequently, Nurr1 recruits the CoREST corepressor complex, resulting in clearance of NF-κB-p65 and transcriptional repression. These studies suggest that Nurr1 protects against loss of dopaminergic neurons in Parkinson’s disease in part by limiting the production of neurotoxic mediators by microglia and astrocytes. PMID:19345186

  17. Selective nanovector mediated treatment of activated proinflammatory microglia/macrophages in spinal cord injury.

    PubMed

    Papa, Simonetta; Rossi, Filippo; Ferrari, Raffaele; Mariani, Alessandro; De Paola, Massimiliano; Caron, Ilaria; Fiordaliso, Fabio; Bisighini, Cinzia; Sammali, Eliana; Colombo, Claudio; Gobbi, Marco; Canovi, Mara; Lucchetti, Jacopo; Peviani, Marco; Morbidelli, Massimo; Forloni, Gianluigi; Perale, Giuseppe; Moscatelli, Davide; Veglianese, Pietro

    2013-11-26

    Much evidence shows that acute and chronic inflammation in spinal cord injury (SCI), characterized by immune cell infiltration and release of inflammatory mediators, is implicated in development of the secondary injury phase that occurs after spinal cord trauma and in the worsening of damage. Activation of microglia/macrophages and the associated inflammatory response appears to be a self-propelling mechanism that leads to progressive neurodegeneration and development of persisting pain state. Recent advances in polymer science have provided a huge amount of innovations leading to increased interest for polymeric nanoparticles (NPs) as drug delivery tools to treat SCI. In this study, we tested and evaluated in vitro and in vivo a new drug delivery nanocarrier: minocycline loaded in NPs composed by a polymer based on poly-ε-caprolactone and polyethylene glycol. These NPs are able to selectively target and modulate, specifically, the activated proinflammatory microglia/macrophages in subacute progression of the secondary injury in SCI mouse model. After minocycline-NPs treatment, we demonstrate a reduced activation and proliferation of microglia/macrophages around the lesion site and a reduction of cells with round shape phagocytic-like phenotype in favor of a more arborized resting-like phenotype with low CD68 staining. Treatment here proposed limits, up to 15 days tested, the proinflammatory stimulus associated with microglia/macrophage activation. This was demonstrated by reduced expression of proinflammatory cytokine IL-6 and persistent reduced expression of CD68 in traumatized site. The nanocarrier drug delivery tool developed here shows potential advantages over the conventionally administered anti-inflammatory therapy, maximizing therapeutic efficiency and reducing side effects.

  18. 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

  19. Linalool Inhibits LPS-Induced Inflammation in BV2 Microglia Cells by Activating Nrf2.

    PubMed

    Li, Yang; Lv, Ou; Zhou, Fenggang; Li, Qingsong; Wu, Zhichao; Zheng, Yongri

    2015-07-01

    Linalool, a natural compound of the essential oils, has been reported to have anti-inflammatory effects. This study aimed to investigate the anti-inflammatory effects and mechanism of linalool in LPS-stimulated BV2 microglia cells. BV2 microglia cells were stimulated with LPS in the presence or absence of linalool. The production of inflammatory mediators TNF-α, IL-1β, NO, and PGE2 as well as Nrf2, HO-1 expression were detected. Our results showed that linalool inhibited LPS-induced TNF-α, IL-1β, NO, and PGE2 production in a dose-dependent manner. Linalool also inhibited LPS-induced NF-κB activation. Treatment of linalool induced nuclear translocation of Nrf2 and expression of HO-1. In addition, our results showed that the anti-inflammatory effect of linalool was attenuated by transfection with Nrf2 siRNA. In conclusion, these results suggested that linalool inhibits LPS-induced inflammation in BV2 microglia cells by activating Nrf2/HO-1 signaling pathway.

  20. Microglia in Glia-Neuron Co-cultures Exhibit Robust Phagocytic Activity Without Concomitant Inflammation or Cytotoxicity.

    PubMed

    Adams, Alexandra C; Kyle, Michele; Beaman-Hall, Carol M; Monaco, Edward A; Cullen, Matthew; Vallano, Mary Lou

    2015-10-01

    A simple method to co-culture granule neurons and glia from a single brain region is described, and microglia activation profiles are assessed in response to naturally occurring neuronal apoptosis, excitotoxin-induced neuronal death, and lipopolysaccharide (LPS) addition. Using neonatal rat cerebellar cortex as a tissue source, glial proliferation is regulated by omission or addition of the mitotic inhibitor cytosine arabinoside (AraC). After 7-8 days in vitro, microglia in AraC(-) cultures are abundant and activated based on their amoeboid morphology, expressions of ED1 and Iba1, and ability to phagocytose polystyrene beads and the majority of neurons undergoing spontaneous apoptosis. Microglia and phagocytic activities are sparse in AraC(+) cultures. Following exposure to excitotoxic kainate concentrations, microglia in AraC(-) cultures phagocytose most dead neurons within 24 h without exacerbating neuronal loss or mounting a strong or sustained inflammatory response. LPS addition induces a robust inflammatory response, based on microglial expressions of TNF-α, COX-2 and iNOS proteins, and mRNAs, whereas these markers are essentially undetectable in control cultures. Thus, the functional effector state of microglia is primed for phagocytosis but not inflammation or cytotoxicity even after kainate exposure that triggers death in the majority of neurons. This model should prove useful in studying the progressive activation states of microglia and factors that promote their conversion to inflammatory and cytotoxic phenotypes.

  1. 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

  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. Identification of a chronic non-neurodegenerative microglia activation state in a mouse model of peroxisomal β-oxidation deficiency.

    PubMed

    Verheijden, Simon; Beckers, Lien; Casazza, Andrea; Butovsky, Oleg; Mazzone, Massimiliano; Baes, Myriam

    2015-09-01

    The functional diversity and molecular adaptations of reactive microglia in the chronically inflamed central nervous system (CNS) are poorly understood. We previously showed that mice lacking multifunctional protein 2 (MFP2), a pivotal enzyme in peroxisomal β-oxidation, persistently accumulate reactive myeloid cells in the gray matter of the CNS. Here, we show that the increased numbers of myeloid cells solely derive from the proliferation of resident microglia and not from infiltrating monocytes. We defined the signature of Mfp2(-/-) microglia by gene expression profiling after acute isolation, which was validated by quantitative polymerase reaction (qPCR), immunohistochemical, and flow cytometric analysis. The features of Mfp2(-/-) microglia were compared with those from SOD1(G93A) mice, an amyotrophic lateral sclerosis model. In contrast to the neurodegenerative milieu of SOD1(G93A) spinal cord, neurons were intact in Mfp2(-/-) brain and Mfp2(-/-) microglia lacked signs of phagocytic and neurotoxic activity. The chronically reactive state of Mfp2(-/-) microglia was accompanied by the downregulation of markers that specify the unique microglial signature in homeostatic conditions. In contrast, mammalian target of rapamycin (mTOR) and downstream glycolytic and protein translation pathways were induced, indicative of metabolic adaptations. Mfp2(-/-) microglia were immunologically activated but not polarized to a pro- or anti-inflammatory phenotype. A peripheral lipopolysaccharide challenge provoked an exaggerated inflammatory response in Mfp2(-/-) brain, consistent with a primed state. Taken together, we demonstrate that chronic activation of resident microglia does not necessarily lead to phagocytosis nor overt neurotoxicity.

  4. 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.

  5. Fluoxetine prevents oligodendrocyte cell death by inhibiting microglia activation after spinal cord injury.

    PubMed

    Lee, Jee Y; Kang, So R; Yune, Tae Y

    2015-05-01

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

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

    PubMed Central

    Lee, Jee Y.; Kang, So R.

    2015-01-01

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

  7. 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...

  8. 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

  9. 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

  10. 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.

  11. Activation of microglia and astrocytes in the nucleus tractus solitarius during ventilatory acclimatization to 10% hypoxia in unanesthetized mice.

    PubMed

    Tadmouri, A; Champagnat, J; Morin-Surun, M P

    2014-05-01

    Nucleus tractus solitarius (NTS) is the integrative sensory relay of autonomic functions in the brainstem. To explore the nonneuronal cellular basis of central chemosensitivity during the first 24 hr of ventilatory acclimatization to hypoxia (VHA), we have investigated glial activation markers in the NTS. Conscious mice (C57/BL6) were placed in a hermetic hypoxia chamber containing a plethysmograph to record ventilation. After 4 days of habituation to the normoxic environment, mice were subjected to physiological hypoxia (10% O2 ) for 1, 6, or 24 hr. To dissociate interactions between microglia and astrocytes, another group received daily minocycline, a microglia activation blocker. By immunochemical localization of astrocytes (GFAP), activated microglia (Cd11b), and total microglia (Iba-1), we identified an oxygen-sensing glial layer in the NTS, in which astrocytes are first activated after 1-6 hr of hypoxia, followed by microglia after 6-24 hr of hypoxia. Minocycline administration suppressed microglial activation and decreased astrocyte activation at 6 hr and VHA at 24 hr of hypoxia. These results suggest that astrocytes contribute to the neuronal response during the first hour of hypoxia, whereas microglial cells, via cross-talk with astrocytes, are involved in the VHA during the first 24 hr of acclimatization.

  12. 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

  13. TGFβ1 inhibits IFNγ-mediated microglia activation and protects mDA neurons from IFNγ-driven neurotoxicity.

    PubMed

    Zhou, Xiaolai; Zöller, Tanja; Krieglstein, Kerstin; Spittau, Björn

    2015-07-01

    Microglia-mediated neuroinflammation has been reported as a common feature of familial and sporadic forms of Parkinson's disease (PD), and a growing body of evidence indicates that onset and progression of PD correlates with the extent of neuroinflammatory responses involving Interferon γ (IFNγ). Transforming growth factor β1 (TGFβ1) has been shown to be a major player in the regulation of microglia activation states and functions and, thus, might be a potential therapeutic agent by shaping microglial activation phenotypes during the course of neurodegenerative diseases such as PD. In this study, we demonstrate that TGFβ1 is able to block IFNγ-induced microglia activation by attenuating STAT1 phosphorylation and IFNγRα expression. Moreover, we identified a set of genes involved in microglial IFNγ signaling transduction that were significantly down-regulated upon TGFβ1 treatment, resulting in decreased sensitivity of microglia toward IFNγ stimuli. Interestingly, genes mediating negative regulation of IFNγ signaling, such as SOCS2 and SOCS6, were up-regulated after TGFβ1 treatment. Finally, we demonstrate that TGFβ1 is capable of protecting midbrain dopaminergic (mDA) neurons from IFNγ-driven neurotoxicity in mixed neuron-glia cultures derived from embryonic day 14 (E14) midbrain tissue. Together, these data underline the importance of TGFβ1 as a key immunoregulatory factor for microglia by silencing IFNγ-mediated microglia activation and, thereby, rescuing mDA neurons from IFNγ-induced neurotoxicity. Interferon γ (IFNγ) is a potent pro-inflammatory factor that triggers the activation of microglia and the subsequent release of neurotoxic factors. Transforming growth factor β1 (TGFβ1) is able to inhibit the IFNγ-mediated activation of microglia, which is characterized by the release of nitric oxide (NO) and tumor necrosis factor α (TNFα). By decreasing the expression of IFNγ-induced genes as well as the signaling receptor IFNγR1, TGFβ1

  14. Stress is critical for LPS-induced activation of microglia and damage in the rat hippocampus.

    PubMed

    Espinosa-Oliva, A M; de Pablos, R M; Villarán, R F; Argüelles, S; Venero, J L; Machado, A; Cano, J

    2011-01-01

    The hippocampus is insensitive to strong inflammatory stimulus under normal conditions and one of the most severely affected areas in Alzheimer's disease. We have analyzed the effect of chronic stress for 9 days in the hippocampus unilaterally injected with LPS. In non-stressed rats, LPS injection failed to activate microglia although a subset of degenerating cells in the CA1 area was evident. This effect was not accompanied by loss of Neu-N positive neurons in the CA1 area. In stressed rats, LPS injection had a dramatic effect in activating microglia along with astrogliosis and BDNF mRNA induction. NeuN immunostaining demonstrated a loss of about 50% of CA1 pyramidal neurons under these conditions. Fluoro jade B histochemistry demonstrated the presence of degenerating cells in most of CA1 area. Mechanistically, combination of chronic stress and LPS resulted in prominent activation of MAPKs including JNK, p38 and ERK clearly different from LPS injection in controls. Further, LPS+stress induced a dramatic decrease in phosphorylated levels of both Akt and CREB, which fully supports a consistent deleterious state in the hippocampal system under these conditions. Treatment with RU486, a potent inhibitor of glucocorticoid receptor activation, significantly protected animals against the deleterious effects observed in LPS-stressed animals.

  15. 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

  16. 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

  17. 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

  18. Regulation of vacuolar H(+)-ATPase in microglia by RANKL.

    PubMed

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

    2009-11-01

    Vacuolar H(+)-ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPases play specialized roles in certain cell types, a capacity that is linked to cell type selective expression of isoforms of some of the subunits. We detected low levels of the a3 isoform of the a-subunit in mouse brain extracts. Examination of various brain-derived cell types by immunoblotting showed a3 was expressed in the N9 microglia cell line and in primary microglia, but not in other cell types. The expression of a3 in osteoclasts requires stimulation by Receptor Activator of Nuclear Factor kappaB-ligand (RANKL). We found that Receptor Activator of Nuclear Factor kappaB (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.

  19. Regulation of Vacuolar H+-ATPase in Microglia by RANKL

    PubMed Central

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

    2009-01-01

    Vacuolar H+-ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPase 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 κ B -ligand (RANKL). We found that Receptor Activator of Nuclear Factor κ 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. PMID:19715671

  20. 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.

  1. 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

  2. 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

  3. Suppression of nuclear factor-κB activation and inflammation in microglia by physically modified saline.

    PubMed

    Khasnavis, Saurabh; Jana, Arundhati; Roy, Avik; Mazumder, Monalisa; Bhushan, Bharat; Wood, Tony; Ghosh, Supurna; Watson, Richard; Pahan, Kalipada

    2012-08-24

    Chronic inflammation involving activated microglia and astroglia is becoming a hallmark of many human diseases, including neurodegenerative disorders. Although NF-κB is a multifunctional transcription factor, it is an important target for controlling inflammation as the transcription of many proinflammatory molecules depends on the activation of NF-κB. Here, we have undertaken a novel approach to attenuate NF-κB activation and associated inflammation in activated glial cells. RNS60 is a 0.9% saline solution containing charge-stabilized nanostructures that are generated by subjecting normal saline to Taylor-Couette-Poiseuille (TCP) flow under elevated oxygen pressure. RNS60, but not normal saline, RNS10.3 (TCP-modified saline without excess oxygen), and PNS60 (saline containing excess oxygen without TCP modification) were found to inhibit the production of nitric oxide (NO) and the expression of inducible NO synthase in activated microglia. Similarly, RNS60 also inhibited the expression of inducible NO synthase in activated astroglia. Inhibition of NF-κB activation by RNS60 suggests that RNS60 exerts its anti-inflammatory effect through the inhibition of NF-κB. Interestingly, RNS60 induced the activation of type IA phosphatidylinositol (PI) 3-kinase and Akt and rapidly up-regulated IκBα, a specific endogenous inhibitor of NF-κB. Inhibition of PI 3-kinase and Akt by either chemical inhibitors or dominant-negative mutants abrogated the RNS60-mediated up-regulation of IκBα. Furthermore, we demonstrate that RNS60 induced the activation of cAMP-response element-binding protein (CREB) via the PI 3-kinase-Akt pathway and that RNS60 up-regulated IκBα via CREB. These results describe a novel anti-inflammatory property of RNS60 via type IA PI 3-kinase-Akt-CREB-mediated up-regulation of IκBα, which may be of therapeutic benefit in neurodegenerative disorders.

  4. Suppression of Nuclear Factor-κB Activation and Inflammation in Microglia by Physically Modified Saline*

    PubMed Central

    Khasnavis, Saurabh; Jana, Arundhati; Roy, Avik; Mazumder, Monalisa; Bhushan, Bharat; Wood, Tony; Ghosh, Supurna; Watson, Richard; Pahan, Kalipada

    2012-01-01

    Chronic inflammation involving activated microglia and astroglia is becoming a hallmark of many human diseases, including neurodegenerative disorders. Although NF-κB is a multifunctional transcription factor, it is an important target for controlling inflammation as the transcription of many proinflammatory molecules depends on the activation of NF-κB. Here, we have undertaken a novel approach to attenuate NF-κB activation and associated inflammation in activated glial cells. RNS60 is a 0.9% saline solution containing charge-stabilized nanostructures that are generated by subjecting normal saline to Taylor-Couette-Poiseuille (TCP) flow under elevated oxygen pressure. RNS60, but not normal saline, RNS10.3 (TCP-modified saline without excess oxygen), and PNS60 (saline containing excess oxygen without TCP modification) were found to inhibit the production of nitric oxide (NO) and the expression of inducible NO synthase in activated microglia. Similarly, RNS60 also inhibited the expression of inducible NO synthase in activated astroglia. Inhibition of NF-κB activation by RNS60 suggests that RNS60 exerts its anti-inflammatory effect through the inhibition of NF-κB. Interestingly, RNS60 induced the activation of type IA phosphatidylinositol (PI) 3-kinase and Akt and rapidly up-regulated IκBα, a specific endogenous inhibitor of NF-κB. Inhibition of PI 3-kinase and Akt by either chemical inhibitors or dominant-negative mutants abrogated the RNS60-mediated up-regulation of IκBα. Furthermore, we demonstrate that RNS60 induced the activation of cAMP-response element-binding protein (CREB) via the PI 3-kinase-Akt pathway and that RNS60 up-regulated IκBα via CREB. These results describe a novel anti-inflammatory property of RNS60 via type IA PI 3-kinase-Akt-CREB-mediated up-regulation of IκBα, which may be of therapeutic benefit in neurodegenerative disorders. PMID:22753407

  5. Early activation of microglia and astrocytes in mouse models of spinocerebellar ataxia type 1.

    PubMed

    Cvetanovic, M; Ingram, M; Orr, H; Opal, P

    2015-03-19

    Spinocerebellar ataxia type 1 (SCA1) is an incurable, dominantly inherited neurodegenerative disease of the cerebellum caused by a polyglutamine-repeat expansion in the protein ataxin-1 (ATXN1). While analysis of human autopsy material indicates significant glial pathology in SCA1, previous research has focused on characterizing neuronal dysfunction. In this study, we characterized astrocytic and microglial response in SCA1 using a comprehensive array of mouse models. We have discovered that astrocytes and microglia are activated very early in SCA1 pathogenesis even when mutant ATXN1 expression was limited to Purkinje neurons. Glial activation occurred in the absence of neuronal death, suggesting that glial activation results from signals emanating from dysfunctional neurons. Finally, in all different models examined glial activation closely correlated with disease progression, supporting the development of glial-based biomarkers to follow disease progression.

  6. Type II Activation of Macrophages and Microglia by Immune Complexes Enhances Th17 Biasing in an IL-6-Independent Manner

    PubMed Central

    Stone, Sarrabeth; La Flamme, Anne Camille

    2016-01-01

    Macrophages can be activated into several distinct activation states. One of these states, type II activation, has a regulatory phenotype characterized by decreased IL-12 and increased IL-10, and has been shown to bias naïve CD4+ T cells to a Th2 response. Microglia, the resident macrophage-like cells in the central nervous system (CNS), are important contributors to neuroinflammation and, thus, we investigated if type II activated microglia could bias CD4+ T cell responses in a similar manner as type II activated macrophages. Using immune complex ligation in the presence of LPS to induce type II activation, we found that both type II macrophages and type II microglia biased CD4+ T cell responses in vitro to express increased levels of IL-17A and CD124. The enhanced IL-17A production occurred independently of IL-6, and IL-10 and IL-12, which were key regulators of IFN-γ production, but were not involved in the increased IL-17A. Finally, we found that another type II-activating compound, glatiramer acetate, did not bias CD4+ T cells to produce enhanced IL-17A. Taken together, this study demonstrates that microglia can be type II activated and, similarly to type II macrophages, can bias CD4+ T cell responses; however, depending on the type II stimulus, the effect on CD4+ T cell subset differentiation may vary. PMID:27732670

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

    PubMed Central

    Derkow, Katja; Krüger, Christina; Dembny, Paul; Lehnardt, Seija

    2015-01-01

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

  8. Minocycline attenuates pain by inhibiting spinal microglia activation in diabetic rats.

    PubMed

    Sun, Jin-Shan; Yang, Yu-Jie; Zhang, Yong-Zhen; Huang, Wen; Li, Zhao-Shen; Zhang, Yong

    2015-08-01

    The mechanisms associated with diabetes-induced neuropathic pain are complex and poorly understood. In order to understand the involvement of spinal microglia activity in diabetic pain, the present study investigated whether minocycline treatment is able to attenuate diabetic pain using a rat model. Diabetes was induced using a single intraperitoneal injection of streptozotocin (STZ). Minocycline was then intrathecally administered to the rats. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were tested weekly. The expression of OX-42, Iba-1, phospho-p38 mitogen-activated protein kinase (MAPK), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS), were examined in the spinal cord in order to evaluate the activation of microglia. The present study demonstrated that rats with STZ-induced diabetes exhibited increased mean plasma glucose concentration, decreased mean body weight and significant pain hypersensitivity compared with control rats. PWT and PWL values of rats with STZ-induced diabetes increased following treatment with minocycline. No differences were observed in expression levels of the microglial activity markers (OX-42, Iba-1 and phospho-p38 MAPK) between rats with STZ-induced diabetes and control rats. However, TNF-α, IL-1β and iNOS expression levels were higher in rats with STZ-induced diabetes compared with control rats. Following treatment with minocycline markers of microglial activation, including cytokines and iNOS, were downregulated in rats with STZ-induced diabetes. The results of the present study indicated that minocycline treatment may inhibit spinal microglial activation and attenuate diabetic pain in rats with STZ-induced diabetes.

  9. Deletion of caspase-8 in mouse myeloid cells blocks microglia pro-inflammatory activation and confers protection in MPTP neurodegeneration model

    PubMed Central

    Kavanagh, Edel; Burguillos, Miguel Angel; Carrillo-Jimenez, Alejandro; Oliva-Martin, María José; Santiago, Martiniano; Rodhe, Johanna; Joseph, Bertrand; Venero, Jose Luis

    2015-01-01

    Increasing evidence involves sustained pro-inflammatory microglia activation in the pathogenesis of different neurodegenerative diseases, particularly Parkinson's disease (PD). We recently uncovered a completely novel and unexpected role for caspase-8 and its downstream substrates caspase-3/7 in the control of microglia activation and associated neurotoxicity to dopaminergic cells. To demonstrate the genetic evidence, mice bearing a floxed allele of CASP8 were crossed onto a transgenic line expressing Cre under the control of Lysozyme 2 gene. Analysis of caspase-8 gene deletion in brain microglia demonstrated a high efficiency in activated but not in resident microglia. Mice were challenged with lipopolysaccharide, a potent inducer of microglia activation, or with MPTP, which promotes specific dopaminergic cell damage and consequent reactive microgliosis. In neither of these models, CASP8 deletion appeared to affect the overall number of microglia expressing the pan specific microglia marker, Iba1. In contrast, CD16/CD32 expression, a microglial pro-inflammatory marker, was found to be negatively affected upon CASP8 deletion. Expression of additional proinflammatory markers were also found to be reduced in response to lipopolysaccharide. Of importance, reduced pro-inflammatory microglia activation was accompanied by a significant protection of the nigro-striatal dopaminergic system in the MPTP mouse model of PD. PMID:26405176

  10. Deletion of caspase-8 in mouse myeloid cells blocks microglia pro-inflammatory activation and confers protection in MPTP neurodegeneration model.

    PubMed

    Kavanagh, Edel; Burguillos, Miguel Angel; Carrillo-Jimenez, Alejandro; Oliva-Martin, María José; Santiago, Martiniano; Rodhe, Johanna; Joseph, Bertrand; Venero, Jose Luis

    2015-09-01

    Increasing evidence involves sustained pro-inflammatory microglia activation in the pathogenesis of different neurodegenerative diseases, particularly Parkinson's disease (PD). We recently uncovered a completely novel and unexpected role for caspase-8 and its downstream substrates caspase-3/7 in the control of microglia activation and associated neurotoxicity to dopaminergic cells. To demonstrate the genetic evidence, mice bearing a floxed allele ofCASP8 were crossed onto a transgenic line expressing Cre under the control of Lysozyme 2 gene. Analysis of caspase-8 gene deletion in brain microglia demonstrated a high efficiency in activated but not in resident microglia. Mice were challenged with lipopolysaccharide, a potent inducer of microglia activation, or with MPTP, which promotes specific dopaminergic cell damage and consequent reactive microgliosis. In neither of these models, CASP8 deletion appeared to affect the overall number of microglia expressing the pan specific microglia marker, Iba1. In contrast, CD16/CD32 expression, a microglial pro-inflammatory marker, was found to be negatively affected upon CASP8 deletion. Expression of additional proinflammatory markers were also found to be reduced in response to lipopolysaccharide. Of importance, reduced pro-inflammatory microglia activation was accompanied by a significant protection of the nigro-striatal dopaminergic system in the MPTP mouse model of PD.

  11. Neuroprotective Effect of 6-Paradol in Focal Cerebral Ischemia Involves the Attenuation of Neuroinflammatory Responses in Activated Microglia

    PubMed Central

    Park, Sung Hyuk; Chun, Kwang-Hoon; Kim, Sun Yeou; Shin, Dong Yun; Choi, Ji Woong

    2015-01-01

    Paradols are non-pungent and biotransformed metabolites of shogaols and reduce inflammatory responses as well as oxidative stress as shogaols. Recently, shogaol has been noted to possess therapeutic potential against several central nervous system (CNS) disorders, including cerebral ischemia, by reducing neuroinflammation in microglia. Therefore, paradol could be used to improve neuroinflammation-associated CNS disorders. Here, we synthesized paradol derivatives (2- to 10-paradols). Through the initial screening for anti-inflammatory activities using lipopolysaccharide (LPS)-stimulated BV2 microglia, 6-paradol was chosen to be the most effective compound without cytotoxicity. Pretreatment with 6-paradol reduced neuroinflammatory responses in LPS-stimulated BV2 microglia by a concentration-dependent manner, which includes reduced NO production by inhibiting iNOS upregulation and lowered secretion of proinflammatory cytokines (IL-6 and TNF-α). To pursue whether the beneficial in vitro effects of 6-paradol leads towards in vivo therapeutic effects on transient focal cerebral ischemia characterized by neuroinflammation, we employed middle cerebral artery occlusion (MCAO)/reperfusion (M/R). Administration of 6-paradol immediately after reperfusion significantly reduced brain damage in M/R-challenged mice as assessed by brain infarction, neurological deficit, and neural cell survival and death. Furthermore, as observed in cultured microglia, 6-paradol administration markedly reduced neuroinflammation in M/R-challenged brains by attenuating microglial activation and reducing the number of cells expressing iNOS and TNF-α, both of which are known to be produced in microglia following M/R challenge. Collectively, this study provides evidences that 6-paradol effectively protects brain after cerebral ischemia, likely by attenuating neuroinflammation in microglia, suggesting it as a potential therapeutic agent to treat cerebral ischemia. PMID:25789481

  12. 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,…

  13. Brain-derived neurotrophic factor contributes to spinal long-term potentiation and mechanical hypersensitivity by activation of spinal microglia in rat.

    PubMed

    Zhou, Li-Jun; Yang, Tao; Wei, Xiao; Liu, Yong; Xin, Wen-Jun; Chen, Yuan; Pang, Rui-Ping; Zang, Ying; Li, Yong-Yong; Liu, Xian-Guo

    2011-02-01

    It has been shown that following peripheral nerve injury brain-derived neurotrophic factor (BDNF) released by activated microglia contributes to neuropathic pain, but whether BDNF affects the function of microglia is still unknown. In the present work we found that spinal application of BDNF, which induced long-term potentiation (LTP) of C-fiber evoked field potentials, activated spinal microglia in naïve animals, while pretreatment with microglia inhibitor minocycline blocked BDNF-induced LTP. In addition, following LTP induction by BDNF, both phosphorylated Src-family kinases (p-SFKs) and phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) were up-regulated only in spinal microglia but not in neurons and astrocytes, whilst spinal application of SFKs inhibitor (PP2 or SU6656) or p38 MAPK inhibitor (SB203580) blocked BDNF-induced LTP and suppressed microglial activation. As spinal LTP at C-fiber synapses is considered to underlie neuropathic pain, we subsequently examined whether BDNF may contribute to mechanical hypersensitivity by activation of spinal microglia using spared nerve injury (SNI) model. Following SNI BDNF and TrkB receptor were up-regulated mainly in dorsal horn neurons and in activated microglia, and p-SFKs and p-p38 MAPK were increased exclusively in microglia. Intrathecal injection of BDNF scavenger TrkB-Fc starting before SNI, which prevented the behavioral sign of neuropathic pain, suppressed both microglial activation and the up-regulation of p-SFKs and p-p38 MAPK produced by SNI. Thus, the increased BDNF/TrkB signaling in spinal dorsal horn may contribute to neuropathic pain by activation of microglia following peripheral nerve injury and inhibition of SFKs or p38 MAPK may selectively inhibit microglia in spinal dorsal horn.

  14. 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

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

    PubMed Central

    Madeddu, Silvia; Woods, Tyson A.; Mukherjee, Piyali; Sturdevant, Dan; 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

  16. 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

  17. 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.

  18. Sequential activation of microglia and astrocyte cytokine expression precedes increased Iba-1 or GFAP immunoreactivity following systemic immune challenge.

    PubMed

    Norden, Diana M; Trojanowski, Paige J; Villanueva, Emmanuel; Navarro, Elisa; Godbout, Jonathan P

    2016-02-01

    Activation of the peripheral immune system elicits a coordinated response from the central nervous system. Key to this immune to brain communication is that glia, microglia, and astrocytes, interpret and propagate inflammatory signals in the brain that influence physiological and behavioral responses. One issue in glial biology is that morphological analysis alone is used to report on glial activation state. Therefore, our objective was to compare behavioral responses after in vivo immune (lipopolysaccharide, LPS) challenge to glial specific mRNA and morphological profiles. Here, LPS challenge induced an immediate but transient sickness response with decreased locomotion and social interaction. Corresponding with active sickness behavior (2-12 h), inflammatory cytokine mRNA expression was elevated in enriched microglia and astrocytes. Although proinflammatory cytokine expression in microglia peaked 2-4 h after LPS, astrocyte cytokine, and chemokine induction was delayed and peaked at 12 h. Morphological alterations in microglia (Iba-1(+)) and astrocytes (GFAP(+)), however, were undetected during this 2-12 h timeframe. Increased Iba-1 immunoreactivity and de-ramified microglia were evident 24 and 48 h after LPS but corresponded to the resolution phase of activation. Morphological alterations in astrocytes were undetected after LPS. Additionally, glial cytokine expression did not correlate with morphology after four repeated LPS injections. In fact, repeated LPS challenge was associated with immune and behavioral tolerance and a less inflammatory microglial profile compared with acute LPS challenge. Overall, induction of glial cytokine expression was sequential, aligned with active sickness behavior, and preceded increased Iba-1 or GFAP immunoreactivity after LPS challenge.

  19. Dibenzocyclooctadiene lignans from Schisandra chinensis and their inhibitory activity on NO production in lipopolysaccharide-activated microglia cells.

    PubMed

    Hu, Di; Yang, Zhiyou; Yao, Xuechun; Wang, Hua; Han, Na; Liu, Zhihui; Wang, Yu; Yang, Jingyu; Yin, Jun

    2014-08-01

    Four dibenzocyclooctadiene lignans, schisanchinins A-D, and 10 known compounds were isolated from the EtOAc extract of fruits of Schisandra chinensis (Turcz.) Baill. Structures of compounds 1-4 were elucidated using a combination of spectroscopic techniques, including MS, UV and IR, NMR ((1)H NMR, (13)C NMR, HMQC, HMBC). The stereochemistry of the chiral centers and the biphenyl configuration were determined using NOESY, as well as analysis of CD spectra. In vitro activity assays showed that 11 of the 14 compounds exhibited inhibitory activity on lipopolysaccharide (LPS)-induced NO release in primary murine BV2 microglia cells.

  20. 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

  1. Inhibition of the activation and recruitment of microglia-like cells protects against neomycin-induced ototoxicity.

    PubMed

    Sun, Shan; Yu, Huiqian; Yu, Hui; Honglin, Mei; Ni, Wenli; Zhang, Yanping; Guo, Luo; He, Yingzi; Xue, Zhen; Ni, Yusu; Li, Jin; Feng, Yi; Chen, Yan; Shao, Ruijin; Chai, Renjie; Li, Huawei

    2015-02-01

    One of the most unfortunate side effects of aminoglycoside (AG) antibiotics such as neomycin is that they target sensory hair cells (HCs) and can cause permanent hearing impairment. We have observed HC loss and microglia-like cell (MLC) activation in the inner ear (cochlea) following neomycin administration. We focused on CX3CL1, a membrane-bound glycoprotein expressed on neurons and endothelial cells, as a way to understand how the MLCs are activated and the role these cells play in HC loss. CX3CL1 is the exclusive ligand for CX3CR1, which is a chemokine receptor expressed on the surface of macrophages and MLCs. In vitro experiments showed that the expression levels of CX3CL1 and CX3CR1 increased in the cochlea upon neomycin treatment, and CX3CL1 was expressed on HCs, while CX3CR1 was expressed on MLCs. When cultured with 1 μg/mL exogenous CX3CL1, MLCs were activated by CX3CL1, and the cytokine level was increased in the cochleae leading to apoptosis in the HCs. In CX3CR1 knockout mice, a significantly greater number of cochlear HCs survived than in wild-type mice when the cochlear explants were cultured with neomycin in vitro. Furthermore, inhibiting the activation of MLCs with minocycline reduced the neomycin-induced HC loss and improved the hearing function in neomycin-treated mice in vivo. Our results demonstrate that CX3CL1-induced MLC activation plays an important role in the induction of HC death and provide evidence for CX3CL1 and CX3CR1 as promising new therapeutic targets for the prevention of hearing loss.

  2. 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

  3. 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

  4. Anti-inflammatory effects of Thymoquinone in activated BV-2 microglia cells

    PubMed Central

    Taka, Equar; Mazzio, Elizabeth A; Goodman, Carl B.; Redmon, Natalie; Flores-Rozas, Hernan; Reams, Renee; Darling-Reed, Selina; Soliman, Karam F.A.

    2015-01-01

    Thymoquinone (TQ), the main pharmacological active ingredient within the black cumin seed (Nigella sativa) is believed to be responsible for therapeutic effects on chronic inflammatory conditions such as arthritis, asthma and neurodegeneration. In this study, we evaluated the potential anti-inflammatory role of TQ in lipopolysaccharide (LPS)-stimulated BV-2 murine microglia cells. The results obtained indicated that TQ was effective in reducing NO2- with an IC50 of 5.04 μM, relative to selective iNOS inhibitor LNIL- L-N6-(1-Iminoethyl)lysine (IC50 4.09 μM). TQ mediated reduction in NO2- was found to parallel the decline of iNOS protein expression as confirmed by immunocytochemistry. In the next study, we evaluated the anti-inflammatory effects of TQ on ninety – six (96) cytokines using a RayBio AAM-CYT-3 and 4 cytokine antibody protein array. Data obtained establish a baseline protein expression profile characteristic of resting BV-2 cells in the order of osteopontin > MIP-1alpha > MIP-1g > IGF-1 and MCP-I. In the presence of LPS [1ug/ml], activated BV-2 cells produced a sharp rise in specific pro-inflammatory cytokines/chemokine’s IL-6, IL-12p40/70, CCL12 /MCP-5, CCL2 / MCP-1, and G-CSF which were attenuated by the addition of TQ (10μM). The TQ mediated attenuation of MCP-5, MCP-1 and IL-6 protein in supernatants from activated BV-2 cells were corroborated by independent ELISA and mRNA expression profiling using RT2 Profiler PCR cytokine arrays. Moreover, the data obtained from the RT2 PCR demonstrated a similar pattern where the LPS mediated elevation of mRNA for IL-6, CCL12 /MCP-5, CCL2 / MCP-1 were significantly attenuated by TQ (10μM). Also, in this study, consistent data were obtained for both protein antibody array densitometry and ELISA assays. In addition, TQ was found to reduce LPS mediated elevation in gene expression of Cxcl10 and a number of other cytokines in the panel. These findings demonstrate the significant anti-inflammatory properties of

  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. 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.

  7. 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.

  8. 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…

  9. Thromboxane A2 receptor antagonist SQ29548 reduces ischemic stroke-induced microglia/macrophages activation and enrichment, and ameliorates brain injury

    PubMed Central

    Yan, Aijuan; Zhang, Tingting; Yang, Xiao; Shao, Jiaxiang; Fu, Ningzhen; Shen, Fanxia; Fu, Yi; Xia, Weiliang

    2016-01-01

    Thromboxane A2 receptor (TXA2R) activation is thought to be involved in thrombosis/hemostasis and inflammation responses. We have previously shown that TXA2R antagonist SQ29548 attenuates BV2 microglia activation by suppression of ERK pathway, but its effect is not tested in vivo. The present study aims to explore the role of TXA2R on microglia/macrophages activation after ischemia/reperfusion brain injury in mice. Adult male ICR mice underwent 90-min transient middle cerebral artery occlusion (tMCAO). Immediately and 24 h after reperfusion, SQ29548 was administered twice to the ipsilateral ventricle (10 μl, 2.6 μmol/ml, per dose). Cerebral infarction volume, inflammatory cytokines release and microglia/macrophages activation were measured using the cresyl violet method, quantitative polymerase chain reaction (qPCR), and immunofluorescence double staining, respectively. Expression of TXA2R was significantly increased in the ipsilateral brain tissue after ischemia/reperfusion, which was also found to co-localize with activated microglia/macrophages in the infarct area. Administration of SQ29548 inhibited microglia/macrophages activation and enrichment, including both M1 and M2 phenotypes, and attenuated ischemia-induced IL-1ß, IL-6, and TNF-α up-regulation and iNOS release. TXA2R antagonist SQ29548 inhibited ischemia-induced inflammatory response and furthermore reduced microglia/macrophages activation and ischemic/reperfusion brain injury. PMID:27775054

  10. 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

  11. Respiratory Viral Infection in Neonatal Piglets Causes Marked Microglia Activation in the Hippocampus and Deficits in Spatial Learning

    PubMed Central

    Elmore, Monica R. P.; Burton, Michael D.; Conrad, Matthew S.; Rytych, Jennifer L.; Van Alstine, William G.

    2014-01-01

    Environmental insults during sensitive periods can affect hippocampal development and function, but little is known about peripheral infection, especially in humans and other animals whose brain is gyrencephalic and experiences major perinatal growth. Using a piglet model, the present study showed that inoculation on postnatal day 7 with the porcine reproductive and respiratory syndrome virus (PRRSV) caused microglial activation within the hippocampus with 82% and 43% of isolated microglia being MHC II+ 13 and 20 d after inoculation, respectively. In control piglets, <5% of microglia isolated from the hippocampus were MHC II+. PRRSV piglets were febrile (p < 0.0001), anorectic (p < 0.0001), and weighed less at the end of the study (p = 0.002) compared with control piglets. Increased inflammatory gene expression (e.g., IL-1β, IL-6, TNF-α, and IFN-γ) was seen across multiple brain regions, including the hippocampus, whereas reductions in CD200, NGF, and MBP were evident. In a test of spatial learning, PRRSV piglets took longer to acquire the task, had a longer latency to choice, and had a higher total distance moved. Overall, these data demonstrate that viral respiratory infection is associated with a marked increase in activated microglia in the hippocampus, neuroinflammation, and impaired performance in a spatial cognitive task. As respiratory infections are common in human neonates and infants, approaches to regulate microglial cell activity are likely to be important. PMID:24501353

  12. Brazilian Green Propolis Suppresses the Hypoxia-Induced Neuroinflammatory Responses by Inhibiting NF-κB Activation in Microglia

    PubMed Central

    Zhu, Aiqin; Takayama, Fumiko; Liu, Yicong; Harada, Yuka; Wu, Shizheng; Nakanishi, Hiroshi

    2013-01-01

    Hypoxia has been recently proposed as a neuroinflammatogen, which drives microglia to produce proinflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6. Considering the fact that propolis has hepatoprotective, antitumor, antioxidative, and anti-inflammatory effects, propolis may have protective effects against the hypoxia-induced neuroinflammatory responses. In this study, propolis (50 μg/mL) was found to significantly inhibit the hypoxia-induced cytotoxicity and the release of proinflammatory cytokines, including IL-1β, TNF-α, and IL-6, by MG6 microglia following hypoxic exposure (1% O2, 24 h). Furthermore, propolis significantly inhibited the hypoxia-induced generation of reactive oxygen species (ROS) from mitochondria and the activation of nuclear factor-κB (NF-κB) in microglia. Moreover, systemic treatment with propolis (8.33 mg/kg, 2 times/day, i.p.) for 7 days significantly suppressed the microglial expression of IL-1β, TNF-α, IL-6, and 8-oxo-deoxyguanosine, a biomarker for oxidative damaged DNA, in the somatosensory cortex of mice subjected to hypoxia exposure (10% O2, 4 h). These observations indicate that propolis suppresses the hypoxia-induced neuroinflammatory responses through inhibition of the NF-κB activation in microglia. Furthermore, increased generation of ROS from the mitochondria is responsible for the NF-κB activation. Therefore, propolis may be beneficial in preventing hypoxia-induced neuroinflammation. PMID:23983903

  13. 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

  14. 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

  15. Perineuronal nets of extracellular matrix around hippocampal interneurons resist destruction by activated microglia in trimethyltin-treated rats.

    PubMed

    Schüppel, Karin; Brauer, Kurt; Härtig, Wolfgang; Grosche, Jens; Earley, Bernadette; Leonard, Brian E; Brückner, Gert

    2002-12-27

    The destruction of the extracellular matrix by inflammatory processes may induce neuronal dysfunction and accelerate neurodegeneration. We describe that chondroitin sulphate proteoglycan-immunoreactive perineuronal nets and the enwrapped interneurons persisted 2 weeks after trimethyltin intoxication of rats (TMT, 8 mg/kg, i.p.) in all regions of the severely affected hippocampus and dentate gyrus, whereas the diffuse immunoreactivity around the CA2 pyramidal cells was reduced. Fluoro-Jade staining of degenerating neurons and staining of microglia by Griffonia simplicifolia agglutinin showed that net-associated neurons survived in the vicinity of damaged pyramidal cells and that perineuronal nets were not removed by activated microglia. We conclude that the extracellular matrix of perineuronal nets resists destruction after TMT treatment in the inflamed neural tissue. A permanent reconstitution of matrix components may be one of the factors that may support the viability of distinct types of neurons during neurodegenerative diseases.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

    2015-06-08

    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.

  4. 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

  5. [Functions of microglia in the healthy brain: focus on neuroplasticity].

    PubMed

    Tishkina, A O; Stepanichev, M Iu; Aniol, V A; Guliaeva, N V

    2014-01-01

    Microglia is in the center of modern research because it is involved in neuroinflammation processes, which is considered as an important part of pathogenesis of many brain pathologies. On the contrary, normal physiological functions of microglia are less studied. Here we review modern data on functioning of microglia in the healthy brain. We consider involvement of microglia in angiogenesis, neurogenesis, synaptogenesis, long-term potentiation, and the mechanisms of microglia-neuron interaction. We further consider modern concept on active interaction of microglia with neurons in developing and healthy mature brain and the essential role of microglia in neuroplasticity mechanisms at various levels.

  6. Effects of local lidocaine treatment before and after median nerve injury on mechanical hypersensitivity and microglia activation in rat cuneate nucleus.

    PubMed

    Lin, Shih-Chang; Yeh, Jiann-Horng; Chen, Chih-Li; Chou, Shiu-Huey; Tsai, Yi-Ju

    2011-04-01

    This study examined the relationship between microglia activation in the cuneate nucleus (CN) and behavioral hypersensitivity after chronic constriction injury (CCI) of the median nerve. We also investigated effects of local lidocaine pre- and post-treatment on microglia activation and development of hypersensitivity in this model. By immunohistochemistry and immunoblotting, little immunoreactivity of OX-42, a microglia activation marker, was detected in the CN of normal rats. As early as 1 day after CCI, there was a significant increase in OX-42 immunoreactivity in the lesion side of CN, which reached a maximum at 14 days. Microinjection of minocycline, a microglia activation inhibitor, into the CN 1 day after CCI attenuated injury-induced behavioral hypersensitivity in a dose-dependent manner. Furthermore, the animals received 1%, 2% or 5% lidocaine 15 min prior to median nerve CCI (pre-treatment), 5h (early post-treatment) or 1 day (late post-treatment) after median nerve CCI. Pre-treatment and early post-treatment with 2% and 5% lidocaine, but not 1% lidocaine, attenuated OX-42 immunoreactivity and behavioral hypersensitivity following median nerve injury. Late post-treatment with 1%, 2%, or 5% lidocaine failed to decrease OX-42 immunoreactivity and mechanical hypersensitivity in CCI rats. In conclusion, median nerve injury-induced microglia activation in the CN modulated development of behavioral hypersensitivity. High-concentration lidocaine was effective in decreasing microglia activation in the CN and in attenuating neuropathic pain sensations at the early stage following nerve injury, when microglia had not yet been activated.

  7. Activation of microglia by endotoxin suppresses the secretion of glial cell line-derived neurotrophic factor (GDNF) through the action of protein kinase C alpha (PKCalpha) and mitogen-activated protein kinases (MAPKS).

    PubMed

    Matsushita, Yuichi; Nakajima, Kazuyuki; Tohyama, Yoko; Kurihara, Tadashi; Kohsaka, Shinichi

    2008-07-01

    The ability of microglia to produce/secrete glial cell line-derived neurotrophic factor (GDNF) in vitro was examined. Immunoblotting analysis revealed that nonstimulated microglia release limited amounts of GDNF with molecular sizes of 14 and 17 kDa. However, the secreted amounts significantly decreased when the microglia were activated with the endotoxin lipopolysaccharide (LPS). Comparison of the amounts of GDNF in the cells and the conditioned medium between the nonstimulated microglia and LPS-stimulated microglia clarified that the secretion of GDNF, but not its production, is strongly suppressed when the microglia are activated with LPS. The inhibitor experiments suggested that the GDNF secretion is depressed by a signaling cascade associated with protein kinase C alpha (PKCalpha) and/or mitogen-activated protein kinases (MAPKs). As expected from the above results, a PKC activator suppressed the secretion of GDNF in nonstimulated microglia. Taken together, these results demonstrated that microglia have the ability to produce and secrete GDNF in vitro, and that the secretion is suppressed by stimulation with endotoxin, probably due to a signaling mechanism involving PKCalpha and/or MAPKs.

  8. Active Play: Exploring the Influences on Children's School Playground Activities

    ERIC Educational Resources Information Center

    Hyndman, Brendon; Benson, Amanda; Telford, Amanda

    2016-01-01

    Because children spend so much of their time in schools, their playgrounds offer a good setting for promoting active play in young lives. Teachers, instead of considering active play a taxing demand on their busy day, have begun to develop an informal curriculum for it. The authors review the research on children's active play and explores its…

  9. 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.

  10. 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.

  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. 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.

  13. Secreted phospholipase A2-IIA-induced a phenotype of activated microglia in BV-2 cells requires epidermal growth factor receptor transactivation and proHB-EGF shedding

    PubMed Central

    2012-01-01

    Background Activation of microglia, the primary component of the innate immune response in the brain, is a hallmark of neuroinflammation in neurodegenerative disorders, including Alzheimer’s disease (AD) and other pathological conditions such as stroke or CNS infection. In response to a variety of insults, microglial cells produce high levels of inflammatory cytokines that are often involved in neuronal injury, and play an important role in the recognition, engulfment, and clearance of apoptotic cells and/or invading microbes. Secreted phospholipase A2-IIA (sPLA2-IIA), an enzyme that interacts with cells involved in the systemic immune/inflammatory response, has been found up-regulated in the cerebrospinal fluid and brain of AD patients. However, despite several approaches, its functions in mediating CNS inflammation remain unknown. In the present study, the role of sPLA2-IIA was examined by investigating its direct effects on microglial cells. Methods Primary and immortalized microglial cells were stimulated by sPLA2-IIA in order to characterize the cytokine-like actions of the phospholipase. The hallmarks of activated microglia analyzed include: mitogenic response, phagocytic capabilities and induction of inflammatory mediators. In addition, we studied several of the potential molecular mechanisms involved in those events. Results The direct exposure of microglial cells to sPLA2-IIA stimulated, in a time- and dose-dependent manner, their phagocytic and proliferative capabilities. sPLA2-IIA also triggered the synthesis of the inflammatory proteins COX-2 and TNFα. In addition, EGFR phosphorylation and shedding of the membrane-anchored heparin-binding EGF-like growth factor (pro-HB-EGF) ectodomain, as well as a rapid activation/phosphorylation of the classical survival proteins ERK, P70S6K and rS6 were induced upon sPLA2-IIA treatment. We further demonstrated that the presence of an EGFR inhibitor (AG1478), a matrix metalloproteinase inhibitor (GM6001), an ADAM

  14. Valproic acid attenuates microgliosis in injured spinal cord and purinergic P2X4 receptor expression in activated microglia.

    PubMed

    Lu, Wen-Hsin; Wang, Chih-Yen; Chen, Po-See; Wang, Jing-Wen; Chuang, De-Maw; Yang, Chung-Shi; Tzeng, Shun-Fen

    2013-05-01

    Peripheral injection with a high dose of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, into animals with mild or moderate spinal cord injury (SCI) for 1 week can reduce spinal cord tissue loss and promote hindlimb locomotor recovery. A purinergic adenosine triphosphate (ATP) receptor subtype, P2X4 receptor (P2X4 R), has been considered as a potential target to diminish SCI-associated inflammatory responses. In this study, using a minipump-based infusion system, we found that intraspinal infusion with VPA for 3 days into injured spinal cord significantly improved hindlimb locomotion of rats with severe SCI induced by a 10-g NYU impactor dropping from the height of 50 mm onto the spinal T9/10 segment. The neuronal fibers in the injured spinal cord tissues were significantly preserved in VPA-treated rats compared with those observed in vehicle-treated animals. Moreover, the accumulation of microglia/macrophages and astrocytes in the injured spinal cord was attenuated in the animal group receiving VPA infusion. VPA also significantly reduced P2X4 R expression post-SCI. Furthermore, in vitro study indicated that VPA, but not the other HDAC inhibitors, sodium butyrate and trichostatin A (TSA), caused downregulation of P2X4 R in microglia activated with lipopolysaccharide (LPS). Moreover, p38 mitogen-activated protein kinase (MAPK)-triggered signaling was involved in the effect of VPA on the inhibition of P2X4 R gene expression. In addition to the findings from others, our results also provide important evidence to show the inhibitory effect of VPA on P2X4 R expression in activated microglia, which may contribute to reduction of SCI-induced gliosis and subsequently preservation of spinal cord tissues. © 2013 Wiley Periodicals, Inc.

  15. 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

  16. 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

  17. 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

  18. 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

  19. Intracerebral transplantation of adipose-derived mesenchymal stem cells alternatively activates microglia and ameliorates neuropathological deficits in Alzheimer's disease mice.

    PubMed

    Ma, Tuo; Gong, Kai; Ao, Qiang; Yan, Yufang; Song, Bo; Huang, Hongyun; Zhang, Xiufang; Gong, Yandao

    2013-01-01

    Recent studies suggest that transplantation of mesenchymal stem cells might have therapeutic effects in preventing pathogenesis of several neurodegenerative disorders. Adipose-derived mesenchymal stem cells (ADSCs) are a promising new cell source for regenerative therapy. However, whether transplantation of ADSCs could actually ameliorate the neuropathological deficits in Alzheimer's disease (AD) and the mechanisms involved has not yet been established. Here, we evaluated the therapeutic effects of intracerebral ADSC transplantation on AD pathology and spatial learning/memory of APP/PS1 double transgenic AD model mice. Results showed that ADSC transplantation dramatically reduced β-amyloid (Aβ) peptide deposition and significantly restored the learning/memory function in APP/PS1 transgenic mice. It was observed that in both regions of the hippocampus and the cortex there were more activated microglia, which preferentially surrounded and infiltrated into plaques after ADSC transplantation. The activated microglia exhibited an alternatively activated phenotype, as indicated by their decreased expression levels of proinflammatory factors and elevated expression levels of alternative activation markers, as well as Aβ-degrading enzymes. In conclusion, ADSC transplantation could modulate microglial activation in AD mice, mitigate AD symptoms, and alleviate cognitive decline, all of which suggest ADSC transplantation as a promising choice for AD therapy. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.

  20. 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…

  1. 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

  2. Microglia in Health and Disease.

    PubMed

    Ransohoff, Richard M; El Khoury, Joseph

    2015-09-09

    Microglia, the major myeloid cells of the central nervous system (CNS) are implicated in physiologic processes and in the pathogenesis of several CNS disorders. Since their initial description early in the 20th century, our ability to identify and isolate microglia has significantly improved and new research is providing insight into the functions of these cells in sickness and in health. Here, we review recent advances in our understanding of the role of microglia in physiological and pathological processes of the CNS with a focus on multiple sclerosis and Alzheimer's disease. Because of the prominent roles CX3CR1 and its ligand fractalkine played in bringing about these advances, we discuss the physiological and pathological roles of microglia as viewed from the CX3CR1-fractalkine perspective, providing a unique viewpoint. Based on the most recent studies of molecular profiling of microglia, we also propose a molecular and functional definition of microglia that incorporates the properties attributed to these cells in recent years.

  3. 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

  4. Microglia Lacking E Prostanoid Receptor Subtype 2 Have Enhanced Aβ Phagocytosis yet Lack Aβ-Activated Neurotoxicity

    PubMed Central

    Shie, Feng-Shiun; Breyer, Richard M.; Montine, Thomas J.

    2005-01-01

    Experimental therapies for Alzheimer’s disease (AD) are focused on enhanced clearance of neurotoxic Aβ peptides from brain. Microglia can be neuroprotective by phagocytosing Aβ; however, this comes at the cost of activated innate immunity that causes paracrine damage to neurons. Here, we show that ablation of E prostanoid receptor subtype 2 (EP2) significantly increased microglial-mediated clearance of Aβ peptides from AD brain sections and enhanced microglial Aβ phagocytosis in cell culture. The enhanced phagocytosis was PKC-dependent and was associated with elevated microglial secretion of the chemoattractant chemokines, macrophage inflammatory protein-1α and macrophage chemoattractant protein-1. This suggested that microglial activation is negatively regulated by EP2 signaling through suppression of prophagocytic cytokine secretion. However, despite this enhancement of Aβ phagocytosis, lack of EP2 completely suppressed Aβ-activated microglia-mediated paracrine neurotoxicity. These data demonstrate that blockade of microglial EP2 is a highly desirable mechanism for AD therapy that can maximize neuroprotective actions while minimizing bystander damage to neurons. PMID:15793296

  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.

  6. 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

  7. Soluble factors released by Toxoplasma gondii-infected astrocytes down-modulate nitric oxide production by gamma interferon-activated microglia and prevent neuronal degeneration.

    PubMed

    Rozenfeld, Claudia; Martinez, Rodrigo; Figueiredo, Rodrigo T; Bozza, Marcelo T; Lima, Flávia R S; Pires, Ana Lúcia; Silva, Patrícia M; Bonomo, Adriana; Lannes-Vieira, Joseli; De Souza, Wanderley; Moura-Neto, Vivaldo

    2003-04-01

    The maintenance of a benign chronic Toxoplasma gondii infection is mainly dependent on the persistent presence of gamma interferon (IFN-gamma) in the central nervous system (CNS). However, IFN-gamma-activated microglia are paradoxically involved in parasitism control and in tissue damage during a broad range of CNS pathologies. In this way, nitric oxide (NO), the main toxic metabolite produced by IFN-gamma-activated microglia, may cause neuronal injury during T. gondii infection. Despite the potential NO toxicity, neurodegeneration is not a common finding during chronic T. gondii infection. In this work, we describe a significant down-modulation of NO production by IFN-gamma-activated microglia in the presence of conditioned medium of T. gondii-infected astrocytes (CMi). The inhibition of NO production was paralleled with recovery of neurite outgrowth when neurons were cocultured with IFN-gamma-activated microglia in the presence of CMi. Moreover, the modulation of NO secretion and the neuroprotective effect were shown to be dependent on prostaglandin E(2) (PGE(2)) production by T. gondii-infected astrocytes and autocrine secretion of interleukin-10 (IL-10) by microglia. These events were partially eliminated when infected astrocytes were treated with aspirin and cocultures were treated with anti-IL-10 neutralizing antibodies and RP-8-Br cyclic AMP (cAMP), a protein kinase A inhibitor. Further, the modulatory effects of CMi were mimicked by the presence of exogenous PGE(2) and by forskolin, an adenylate cyclase activator. Altogether, these data point to a T. gondii-triggered regulatory mechanism involving PGE(2) secretion by astrocytes and cAMP-dependent IL-10 secretion by microglia. This may reduce host tissue inflammation, thus avoiding neuron damage during an established Th1 protective immune response. PMID:12654825

  8. Microglia during development and aging.

    PubMed

    Harry, G Jean

    2013-09-01

    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, and axonal degeneration. Changes in microglia 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 microglia potentially 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.

  9. 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

  10. 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.

  11. Resveratrol potently reduces prostaglandin E2 production and free radical formation in lipopolysaccharide-activated primary rat microglia

    PubMed Central

    Candelario-Jalil, Eduardo; de Oliveira, Antonio C Pinheiro; Gräf, Sybille; Bhatia, Harsharan S; Hüll, Michael; Muñoz, Eduardo; Fiebich, Bernd L

    2007-01-01

    Background Neuroinflammatory responses are triggered by diverse ethiologies and can provide either beneficial or harmful results. Microglial cells are the major cell type involved in neuroinflammation, releasing several mediators, which contribute to the neuronal demise in several diseases including cerebral ischemia and neurodegenerative disorders. Attenuation of microglial activation has been shown to confer protection against different types of brain injury. Recent evidence suggests that resveratrol has anti-inflammatory and potent antioxidant properties. It has been also shown that resveratrol is a potent inhibitor of cyclooxygenase (COX)-1 activity. Previous findings have demonstrated that this compound is able to reduce neuronal injury in different models, both in vitro and in vivo. The aim of this study was to examine whether resveratrol is able to reduce prostaglandin E2 (PGE2) and 8-iso-prostaglandin F2α (8-iso-PGF2α) production by lipopolysaccharide (LPS)-activated primary rat microglia. Methods Primary microglial cell cultures were prepared from cerebral cortices of neonatal rats. Microglial cells were stimulated with 10 ng/ml of LPS in the presence or absence of different concentrations of resveratrol (1–50 μM). After 24 h incubation, culture media were collected to measure the production of PGE2 and 8-iso-PGF2α using enzyme immunoassays. Protein levels of COX-1, COX-2 and microsomal prostaglandin E synthase-1 (mPGES-1) were studied by Western blotting after 24 h of incubation with LPS. Expression of mPGES-1 at the mRNA level was investigated using reverse transcription-polymerase chain reaction (RT-PCR) analysis. Results Our results indicate that resveratrol potently reduced LPS-induced PGE2 synthesis and the formation of 8-iso-PGF2α, a measure of free radical production. Interestingly, resveratrol dose-dependently reduced the expression (mRNA and protein) of mPGES-1, which is a key enzyme responsible for the synthesis of PGE2 by activated

  12. Spreading depression requires microglia and is decreased by their M2a polarization from environmental enrichment.

    PubMed

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

    2014-07-01

    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 proinflammatory 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 proinflammatory 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.

  13. 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

  14. Neonatal peripheral immune challenge activates microglia and inhibits neurogenesis in the developing murine hippocampus.

    PubMed

    Smith, Peter L P; Hagberg, Henrik; Naylor, Andrew S; Mallard, Carina

    2014-01-01

    The early postnatal period represents an important window in rodent hippocampal development with peak hilar neurogenesis and widespread microgliogenesis occurring in the first week of life. Inflammation occurring during this period may negatively influence development, potentially facilitating or increasing susceptibility to later-life pathology. We administered the Gram-negative bacterial coat protein lipopolysaccharide (LPS) systemically at postnatal day 5 (1 mg/kg i.p.) and assessed potential effects on microgliogenesis, inflammation and neurogenesis in the developing hippocampus. LPS administration led to an acute but transient increase in absolute number and density of ionized calcium-binding adaptor molecule 1-immunoreactive microglia, a change attributable to increased proliferation of central nervous system-resident microglia/microglial precursor cells but not infiltration of peripheral monocyte-derived macrophages. qRT-PCR analysis of hippocampal gene expression showed these LPS-mediated changes to be associated with persistent dysregulation of genes associated with both M1 and M2 microglial phenotypes, indicating prolonged alteration in hippocampal inflammatory status. Further, analysis of progenitor cell regulation in the hippocampal subgranular zone revealed a transient inhibition of the neuronal differentiation pathway up to 2 weeks after LPS administration, a change occurring specifically through effects on type 3 neural progenitor cells and independently of altered cell proliferation or survival of newly born cells. Together, our results show that systemic inflammation occurring during the early neonatal period is sufficient to alter inflammatory status and dysregulate the ongoing process of neurogenesis in the developing hippocampal germinal niche.

  15. 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.

  16. Folic Acid Is Able to Polarize the Inflammatory Response in LPS Activated Microglia by Regulating Multiple Signaling Pathways

    PubMed Central

    Salvatore, Rosaria; Porro, Chiara; Trotta, Teresa

    2016-01-01

    We investigated the ability of folic acid to modulate the inflammatory responses of LPS activated BV-2 microglia cells and the signal transduction pathways involved. To this aim, the BV-2 cell line was exposed to LPS as a proinflammatory response inducer, in presence or absence of various concentrations of folic acid. The production of nitric oxide (NO) was determined by the Griess test. The levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-10 were determined by ELISA. Inducible NO synthase (iNOS), nuclear transcription factor-kappa B (NF-κB) p65, MAPKs protein, and suppressors of cytokine signaling (SOCS)1 and SOCS3 were analyzed by western blotting. TNF-α and IL-1β, as well as iNOS dependent NO production, resulted significantly inhibited by folic acid pretreatment in LPS-activated BV-2 cells. We also observed that folic acid dose-dependently upregulated both SOCS1 and SOCS3 expression in BV-2 cells, leading to an increased expression of the anti-inflammatory cytokine IL-10. Finally, p-IκBα, which indirectly reflects NF-κB complex activation, and JNK phosphorylation resulted dose-dependently downregulated by folic acid pretreatment of LPS-activated cells, whereas p38 MAPK phosphorylation resulted significantly upregulated by folic acid treatment. Overall, these results demonstrated that folic acid was able to modulate the inflammatory response in microglia cells, shifting proinflammatory versus anti-inflammatory responses through regulating multiple signaling pathways. PMID:27738387

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

    PubMed

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

    2013-09-01

    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.

  18. Fluoro-Jade B staining as useful tool to identify activated microglia and astrocytes in a mouse transgenic model of Alzheimer's disease.

    PubMed

    Damjanac, Milena; Rioux Bilan, Agnès; Barrier, Laurence; Pontcharraud, Raymond; Anne, Cantereau; Hugon, Jacques; Page, Guylène

    2007-01-12

    Fluoro-Jade B is known as a high affinity fluorescent marker for the localization of neuronal degeneration during acute neuronal distress. However, one study suggested that fluoro-Jade B stains reactive astroglia in the primate cerebral cortex. In this study, we analyzed the staining of fluoro-Jade B alone or combined with specific markers for detection of glial fibrillary acidic protein (GFAP) or activated CD68 microglia in the double APP(SL)/PS1 KI transgenic mice of Alzheimer's disease (AD), which display a massive neuronal loss in the CA1 region of the hippocampus. Our results showed that fluoro-Jade B did not stain normal and degenerating neurons in this double mouse transgenic model. Fluoro-Jade B was co-localized with Abeta in the core of amyloid deposits and in glia-like cells expressing Abeta. Furthermore, fluoro-Jade B was co-localized with CD68/macrosialin, a specific marker of activated microglia, and with GFAP for astrocytes in APP(SL)/PS1 KI transgenic mice of AD. Taken together, these findings showed that fluoro-Jade B can be used to label activated microglia and astrocytes which are abundant in the brain of these AD transgenic mice. It could stain degenerating neurons as a result of acute insult while it could label activated microglia and astrocytes during a chronic neuronal degenerative process such as AD for example.

  19. 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...

  20. 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

  1. 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

  2. Physical Activity Play: The Nature and Function of a Neglected Aspect of Play.

    ERIC Educational Resources Information Center

    Pellegrini, A. D.; Smith, Peter K.

    1998-01-01

    Considers the nature and developmental functions of physical activity play. Distinguishes three kinds of physical activity play with consecutive age peaks: rhythmic stereotypies, exercise play, and rough-and-tumble play. Considers gender differences and function in terms of immediate and deferred consequences in physical, cognitive, and social…

  3. Involvement of microRNA in microglia-mediated immune response.

    PubMed

    Guedes, J; Cardoso, A L C; Pedroso de Lima, M C

    2013-01-01

    MicroRNAs (miRNAs) are an abundant class of small noncoding RNA molecules that play an important role in the regulation of gene expression at the posttranscriptional level. Due to their ability to simultaneously modulate the fate of different genes, these molecules are particularly well suited to act as key regulators during immune cell differentiation and activation, and their dysfunction can contribute to pathological conditions associated with neuroinflammation. Recent studies have addressed the role of miRNAs in the differentiation of progenitor cells into microglia and in the activation process, aiming at clarifying the origin of adult microglia cells and the contribution of the central nervous system (CNS) environment to microglia phenotype, in health and disease. Altered expression of several miRNAs has been associated with Alzheimer's disease, multiple sclerosis, and ischemic injury, hence strongly advocating the use of these small molecules as disease markers and new therapeutic targets. This review summarizes the recent advances in the field of miRNA-mediated regulation of microglia development and activation. We discuss the role of specific miRNAs in the maintenance and switching of microglia activation states and illustrate the potential of this class of nucleic acids both as biomarkers of inflammation and new therapeutic tools for the modulation of microglia behavior in the CNS.

  4. Neuron-derived IgG protects dopaminergic neurons from insult by 6-OHDA and activates microglia through the FcγR I and TLR4 pathways.

    PubMed

    Zhang, Jie; Niu, Na; Wang, Mingyu; McNutt, Michael A; Zhang, Donghong; Zhang, Baogang; Lu, Shijun; Liu, Yuqing; Liu, Zhihui

    2013-08-01

    Oxidative and immune attacks from the environment or microglia have been implicated in the loss of dopaminergic neurons of Parkinson's disease. The role of IgG which is an important immunologic molecule in the process of Parkinson's disease has been unclear. Evidence suggests that IgG can be produced by neurons in addition to its traditionally recognized source B lymphocytes, but its function in neurons is poorly understood. In this study, extensive expression of neuron-derived IgG was demonstrated in dopaminergic neurons of human and rat mesencephalon. With an in vitro Parkinson's disease model, we found that neuron-derived IgG can improve the survival and reduce apoptosis of dopaminergic neurons induced by 6-hydroxydopamine toxicity, and also depress the release of NO from microglia triggered by 6-hydroxydopamine. Expression of TNF-α and IL-10 in microglia was elevated to protective levels by neuron-derived IgG at a physiologic level via the FcγR I and TLR4 pathways and microglial activation could be attenuated by IgG blocking. All these data suggested that neuron-derived IgG may exert a self-protective function by activating microglia properly, and IgG may be involved in maintaining immunity homeostasis in the central nervous system and serve as an active factor under pathological conditions such as Parkinson's disease.

  5. Reduced Alzheimer's disease pathology by St. John's Wort treatment is independent of hyperforin and facilitated by ABCC1 and microglia activation in mice.

    PubMed

    Hofrichter, Jacqueline; Krohn, Markus; Schumacher, Toni; Lange, Cathleen; Feistel, Björn; Walbroel, Bernd; Heinze, Hans-Jochen; Crockett, Sara; Sharbel, Timothy F; Pahnke, Jens

    2013-12-01

    Soluble β-amyloid peptides (Aβ) and small Aβ oligomers represent the most toxic peptide moieties recognized in brains affected by Alzheimer's disease (AD). Here we provide the first evidence that specific St. John's wort (SJW) extracts both attenuate Aβ-induced histopathology and alleviate memory impairments in APP-transgenic mice. Importantly, these effects are attained independently of hyperforin. Specifically, two extracts characterized by low hyperforin content (i) significantly decrease intracerebral Aβ42 levels, (ii) decrease the number and size of amyloid plaques, (iii) rescue neocortical neurons, (iv) restore cognition to normal levels, and (iv) activate microglia in vitro and in vivo. Mechanistically, we reveal that the reduction of soluble Aβ42 species is the consequence of a highly increased export activity in the bloodbrain barrier ABCC1transporter, which was found to play a fundamental role in Aβ excretion into the bloodstream. These data (i) support the significant beneficial potential of SJW extracts on AD proteopathy, and (ii) demonstrate for the first time that hyperforin concentration does not necessarily correlate with their therapeutic effects. Hence, by activating ABC transporters, specific extracts of SJW may be used to treat AD and other diseases involving peptide accumulation and cognition impairment. We propose that the anti-depressant and anti-dementia effects of these hyperforin-reduced phytoextracts could be combined for treatment of the elderly, with a concomitant reduction in deleterious hyperforin-related side effects.

  6. 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

  7. 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…

  8. Mechanisms involved in the modulation of astroglial resistance to oxidative stress induced by activated microglia: antioxidative systems, peroxide elimination, radical generation, lipid peroxidation.

    PubMed

    Röhl, Claudia; Armbrust, Elisabeth; Herbst, Eva; Jess, Anne; Gülden, Michael; Maser, Edmund; Rimbach, Gerald; Bösch-Saadatmandi, Christine

    2010-05-01

    Microglia and astrocytes are the cellular key players in many neurological disorders associated with oxidative stress and neuroinflammation. Previously, we have shown that microglia activated by lipopolysaccharides (LPS) induce the expression of antioxidative enzymes in astrocytes and render them more resistant to hydrogen peroxide (H2O2). In this study, we examined the mechanisms involved with respect to the cellular action of different peroxides, the ability to detoxify peroxides, and the status of further antioxidative systems. Astrocytes were treated for 3 days with medium conditioned by purified quiescent (microglia-conditioned medium, MCM[-]) or LPS-activated (MCM[+]) microglia. MCM[+] reduced the cytotoxicity of the organic cumene hydroperoxide in addition to that of H2O2. Increased peroxide resistance was not accompanied by an improved ability of astrocytes to remove H2O2 or an increased expression/activity of peroxide eliminating antioxidative enzymes. Neither peroxide-induced radical generation nor lipid peroxidation were selectively affected in MCM[+] treated astrocytes. The glutathione content of peroxide resistant astrocytes, however, was increased and superoxide dismutase and heme oxygenase were found to be upregulated. These changes are likely to contribute to the higher peroxide resistance of MCM[+] treated astrocytes by improving their ability to detoxify reactive oxygen radicals and oxidation products. For C6 astroglioma cells a protective effect of microglia-derived factors could not be observed, underlining the difference of primary cells and cell lines concerning their mechanisms of oxidative stress resistance. Our results indicate the importance of microglial-astroglial cell interactions during neuroinflammatory processes.

  9. 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.

  10. 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 Central

    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

  11. COL-3, a chemically modified tetracycline, inhibits lipopolysaccharide-induced microglia activation and cytokine expression in the brain.

    PubMed

    Edan, Rawan Abdulhameed; Luqmani, Yunus A; Masocha, Willias

    2013-01-01

    Microglia activation results in release of proinflammatory molecules including cytokines, which contribute to neuronal damage in the central nervous system (CNS) if not controlled. Tetracycline antibiotics such as minocycline inhibit microglial activation and cytokine expression during CNS inflammation. In the present study we found that administration of chemically modified tetracycline-3 (COL-3), inhibits lipopolysaccharide (LPS)-induced microglial and p38 MAPK activation, as well as the increase in TNF-α, but not IL-1β expression, in the brains of BALB/c mice. COL-3 has been described to have no antibacterial activity. We observed that COL-3 had no activity against a Gram-negative bacteria, Escherichia coli; however surprisingly, COL-3 had antibacterial activity against a Gram-positive bacteria Staphylococcus aureus, with a minimum inhibitory concentration of 1 mg/ml. Our data show that COL-3 has some antibacterial activity against S. aureus, inhibits LPS-induced neuroinflammation, and displays potential as a therapeutic agent for treatment of conditions involving CNS inflammation.

  12. 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.

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

    PubMed Central

    Nau, Roland; Ribes, Sandra; Djukic, Marija; Eiffert, Helmut

    2014-01-01

    In healthy individuals, infections of the central nervous system (CNS) are comparatively rare. Based on the ability of microglial cells to phagocytose and kill pathogens and on clinical findings in immunocompromised patients with CNS infections, we hypothesize that an intact microglial function is crucial to protect the brain from infections. Phagocytosis of pathogens by microglial cells can be stimulated by agonists of receptors of the innate immune system. Enhancing this pathway to increase the resistance of the brain to infections entails the risk of inducing collateral damage to the nervous tissue. The diversity of microglial cells opens avenue to selectively stimulate sub-populations responsible for the defence against pathogens without stimulating sub-populations which are responsible for collateral damage to the nervous tissue. Palmitoylethanolamide (PEA), an endogenous lipid, increased phagocytosis of bacteria by microglial cells in vitro without a measurable proinflammatory effect. It was tested clinically apparently without severe side effects. Glatiramer acetate increased phagocytosis of latex beads by microglia and monocytes, and dimethyl fumarate enhanced elimination of human immunodeficiency virus from infected macrophages without inducing a release of proinflammatory compounds. Therefore, the discovery of compounds which stimulate the elimination of pathogens without collateral damage of neuronal structures appears an achievable goal. PEA and, with limitations, glatiramer acetate and dimethyl fumarate appear promising candidates. PMID:24904283

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

    PubMed

    Nau, Roland; Ribes, Sandra; Djukic, Marija; Eiffert, Helmut

    2014-01-01

    In healthy individuals, infections of the central nervous system (CNS) are comparatively rare. Based on the ability of microglial cells to phagocytose and kill pathogens and on clinical findings in immunocompromised patients with CNS infections, we hypothesize that an intact microglial function is crucial to protect the brain from infections. Phagocytosis of pathogens by microglial cells can be stimulated by agonists of receptors of the innate immune system. Enhancing this pathway to increase the resistance of the brain to infections entails the risk of inducing collateral damage to the nervous tissue. The diversity of microglial cells opens avenue to selectively stimulate sub-populations responsible for the defence against pathogens without stimulating sub-populations which are responsible for collateral damage to the nervous tissue. Palmitoylethanolamide (PEA), an endogenous lipid, increased phagocytosis of bacteria by microglial cells in vitro without a measurable proinflammatory effect. It was tested clinically apparently without severe side effects. Glatiramer acetate increased phagocytosis of latex beads by microglia and monocytes, and dimethyl fumarate enhanced elimination of human immunodeficiency virus from infected macrophages without inducing a release of proinflammatory compounds. Therefore, the discovery of compounds which stimulate the elimination of pathogens without collateral damage of neuronal structures appears an achievable goal. PEA and, with limitations, glatiramer acetate and dimethyl fumarate appear promising candidates. PMID:24904283

  15. 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

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

    PubMed

    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

  17. MMP-3 secreted from endothelial cells of blood vessels after spinal cord injury activates microglia, leading to oligodendrocyte cell death.

    PubMed

    Lee, Jee Y; Choi, Hae Y; Yune, Tae Y

    2015-10-01

    The activation of microglia after spinal cord injury (SCI) contributes to secondary damage by producing pro-inflammatory cytokines and mediators, leading to cell death of oligodendrocytes and neurons. Here, we show that matrix metalloprotease-3 (MMP-3) produced and secreted in the endothelial cells of blood vessels after SCI mediates microglial activation. MMP-3 was produced and secreted in bEnd.3 cells, a mouse brain-derived endothelial cell line, by oxygen-glucose deprivation/reoxygenation (OGD/RO). OGD/RO-induced MMP-3 expression and activity was also significantly inhibited by ghrelin, which was dependent on the ghrelin receptor GHS-R1a. Furthermore, the secreted MMP-3 from OGD/RO-induced bEnd.3 cells activated BV-2 cells, a murine microglial cell line. We also found that microglial activation after SCI was attenuated in MMP-3 knockout (KO) mice compared with wild type (WT) mice. Both p38 mitogen-activated protein kinase (MAPK) activation and pro-nerve growth factor (proNGF) production were more inhibited in MMP-3 KO than WT mice at 5d after injury. When WT mice were treated with Mmp-3 siRNA after injury, MMP-3 activity, microglial activation, p38MAPK activation and proNGF expression were significantly inhibited. Ghrelin treatment also significantly inhibited MMP-3 expression and activation after SCI, which was dependent on GHS-R1a. Finally, RhoA activation and oligodendrocyte cell death after injury were attenuated by Mmp-3 siRNA or ghrelin treatment compared with vehicle control. Thus, our study indicates that MMP-3 produced in blood vessel endothelial cells after SCI serves as an endogenous molecule for microglial activation followed by p38MAPK activation and proNGF production, and further indicates that the protective effect of ghrelin on oligodendrocytes cell death may be at least partly mediated by the inhibition of MMP-3-induced microglial activation after SCI.

  18. Nutrients, Microglia Aging, and Brain Aging.

    PubMed

    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

  19. Age-related decline of myelin proteins is highly correlated with activation of astrocytes and microglia in the rat CNS.

    PubMed

    Xie, Fang; Zhang, Jiu-Cong; Fu, Han; Chen, Jun

    2013-11-01

    It has been shown that aging can greatly influence the integrity and ultrastructure of white matter and the myelin sheath; however, studies regarding the effects of aging on the expression of myelin proteins are still limited. In the present study, immunohistochemical mapping was used to investigate the overall expression of myelin basic protein (Mbp) and myelin oligodendrocyte glycoprotein (Mog) in the central nervous system (CNS) of rats in postnatal months 2, 5, 18 and 26. Astrocyte and microglia activation was also detected by glial fibrillary acidic protein (GFAP) or ionized calcium-binding adaptor molecule 1 (Iba1) staining and western blotting. A significant decline of Mbp and Mog was identified as a universal alteration in the CNS of aged rats. Aging also induced significant astrocyte and microglial activation. Correlation analysis indicated a negative correlation between the reduction of age‑related myelin proteins and glial activation in aging. This correlation of myelin breakdown and glial activation in aging may reveal new evidence in connecting the inflammation and myelin breakdown mechanism of age‑related neurodegenerative diseases.

  20. Dual polarization of microglia isolated from mixed glial cell cultures.

    PubMed

    Ju, Lili; Zeng, Hui; Chen, Yun; Wu, Yanhong; Wang, Beibei; Xu, Qunyuan

    2015-09-01

    Microglia are versatile immune effector cells of the CNS and are sensitive to various stimuli. The different methods used to isolate microglia may affect some of their characteristics, such as their polarization state. The influence of cell sorting methods on the polarization state of microglia has never been studied. Mixed glial culture system (MGCS) and magnetic activated cell sorting (MACS) are two methods that are commonly used to purify microglia. This study compares the immunological states between microglia isolated by MGCS and microglia isolated by MACS. We show that microglia isolated by MGCS exhibit a stronger immune-activated state than microglia isolated by MACS. They present an elevated phagocytic ability and high levels of markers associated with classical activation (M1) and alternative activation (M2). In addition, high levels of M1-type and M2-type chemokine (C-C motif) ligand 2 and transforming growth factor-β1 were detected in the culture medium of mixed glial cells. Our results show that microglia isolated by MGCS are in an immune-activated state, whereas microglia isolated by MACS appear to be closer to their primary in vivo state. Therefore, the immune status of microglia, depending on the protocol used to purify them, should be carefully considered in neuropathology research.

  1. 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

  2. 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

  3. 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…

  4. 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…

  5. 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,…

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

    PubMed Central

    Gentile, Antonietta; De Vito, Francesca; Fresegna, Diego; Musella, Alessandra; Buttari, Fabio; Bullitta, Silvia; Mandolesi, Georgia; Centonze, Diego

    2015-01-01

    Microglia is increasingly recognized to play a crucial role in the pathogenesis of psychiatric diseases. In particular, microglia may be the cellular link between inflammation and behavioral alterations: by releasing a number of soluble factors, among which pro-inflammatory cytokines, that can regulate synaptic activity, thereby leading to perturbation of behavior. In multiple sclerosis (MS), the most common neuroinflammatory disorder affecting young adults, microglia activation and dysfunction may account for mood symptoms, like depression and anxiety, that are often diagnosed in patients even in the absence of motor disability. Behavioral studies in experimental autoimmune encephalomyelitis (EAE), the animal model of MS, have shown that emotional changes occur early in the disease and in correlation to inflammatory mediator and neurotransmitter level alterations. However, such studies lack a full and comprehensive analysis of the role played by microglia in EAE-behavioral syndrome. We review the experimental studies addressing behavioral symptoms in EAE, and propose the study of neuron-glia interaction as a powerful but still poorly explored tool to investigate the burden of microglia in mood alterations associated to MS. PMID:26161070

  7. 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

  8. 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.

  9. 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

  10. Microglia and their CX3CR1 signaling are involved in hippocampal- but not olfactory bulb-related memory and neurogenesis.

    PubMed

    Reshef, Ronen; Kreisel, Tirzah; Beroukhim Kay, Dorsa; Yirmiya, Raz

    2014-10-01

    Recent studies demonstrate that microglia play an important role in cognitive and neuroplasticity processes, at least partly via microglial CX3C receptor 1 (CX3CR1) signaling. Furthermore, microglia are responsive to environmental enrichment (EE), which modulates learning, memory and neurogenesis. In the present study we examined the role of microglial CX3CR1 signaling in hippocampal- and olfactory-bulb (OB)-related memory and neurogenesis in homozygous mice with microglia-specific transgenic expression of GFP under the CX3CR1 promoter (CX3CR1(-/-) mice), in which the CX3CR1 gene is functionally deleted, as well as heterozygous CX3CR1(+/-) and WT controls. We report that the CX3CR1-deficient mice displayed better hippocampal-dependent memory functioning and olfactory recognition, along with increased number and soma size of hippocampal microglia, suggestive of mild activation status, but no changes in OB microglia. A similar increase in hippocampal-dependent memory functioning and microglia number was also induced by pharmacological inhibition of CX3CR1 signaling, using chronic (2weeks) i.c.v. administration of CX3CR1 blocking antibody. In control mice, EE improved hippocampal-dependent memory and neurogenesis, and increased hippocampal microglia number and soma size, whereas odor enrichment (OE) improved olfactory recognition and OB neurogenesis without changing OB microglia status. In CX3CR1-deficient mice, EE and OE did not produce any further improvement in memory functioning or neurogenesis and had no effect on microglial status. These results support the notion that in the hippocampus microglia and their interactions with neurons via the CX3CR1 play an important role in memory functioning and neurogenesis, whereas in the OB microglia do not seem to be involved in these processes.

  11. Protective Microglia and Their Regulation in Parkinson’s Disease

    PubMed Central

    Le, Weidong; Wu, Junjiao; Tang, Yu

    2016-01-01

    Microglia-mediated neuroinflammation is a hallmark of Parkinson’s disease (PD). In the brains of patients with PD, microglia have both neurotoxic and neuroprotective effects, depending on their activation state. In this review, we focus on recent research demonstrating the neuroprotective role of microglia in PD. Accumulating evidence indicates that the protective mechanisms of microglia may result from their regulation of transrepression pathways via nuclear receptors, anti-inflammatory responses, neuron–microglia crosstalk, histone modification, and microRNA regulation. All of these mechanisms work together to suppress the production of neurotoxic inflammatory components. However, during the progression of PD, the detrimental effects of inflammation overpower the protective actions of microglia. Therefore, an in-depth exploration of the mechanisms underlying microglial neuroprotection, and a means of promoting the transformation of microglia to the protective phenotype, are urgently needed for the treatment of PD. PMID:27708561

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

    PubMed

    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

  13. 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

  14. Children's active play: self-reported motivators, barriers and facilitators

    PubMed Central

    2011-01-01

    Background Physical activity has important benefits for children's physical health and mental wellbeing, but many children do not meet recommended levels. Research suggests that active play has the potential to make a valuable contribution to children's overall physical activity, whilst providing additional cognitive, social and emotional benefits. However, relatively little is known about the determinants of UK children's active play. Understanding these factors provides the critical first step in developing interventions to increase children's active play, and therefore overall physical activity. Methods Eleven focus groups were conducted with 77, 10-11 year old children from four primary schools in Bristol, UK. Focus groups examined: (i) factors which motivate children to take part in active play; (ii) factors which limit children's active play and (iii) factors which facilitate children's active play. All focus groups were audio-taped and transcribed verbatim. Data were analysed using a thematic approach. Results Children were motivated to engage in active play because they perceived it to be enjoyable, to prevent boredom, to have physical and mental health benefits and to provide freedom from adult control, rules and structure. However, children's active play was constrained by a number of factors, including rainy weather and fear of groups of teenagers in their play spaces. Some features of the physical environment facilitated children's active play, including the presence of green spaces and cul-de-sacs in the neighbourhood. Additionally, children's use of mobile phones when playing away from home was reported to help to alleviate parents' safety fears, and therefore assist children's active play. Conclusions Children express a range of motivational and environmental factors that constrain and facilitate their active play. Consideration of these factors should improve effectiveness of interventions designed to increase active play. PMID:21663605

  15. The microglia in healthy and diseased retina.

    PubMed

    Li, Lu; Eter, Nicole; Heiduschka, Peter

    2015-07-01

    The microglia are the immune cells of the central nervous system and, also the retina. They fulfil several tasks of surveillance in the healthy retina. In case of an injury or disease, microglia become activated and tries to repair the damage. However, in a lot of cases it does not work, and microglia deteriorate the situation by releasing toxic and pro-inflammatory compounds. Moreover, they further promote degenerative processes by attacking and phagocytosing damaged neurones and photoreceptors that otherwise would possibly have the chance to survive. Such deleterious action of the microglia has been observed in degeneration of retinal ganglion cells and photoreceptors, and it takes place in hereditary diseases, infections as well as in case of traumatic or light injuries. Therefore, a number of attempts has been undertaken so far to inhibit the microglia, with varying success. The task remains to study behaviour of the microglia and their interaction with other retinal cell populations in more detail with respect to released factors and expressed receptors including the time points of the corresponding events. The goal has to be to find a better balance between helpful and detrimental actions of the microglia.

  16. 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

  17. 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.

  18. Child's Play: An Activities and Materials Handbook.

    ERIC Educational Resources Information Center

    Trencher, Barbara R.

    This handbook, the third printing of the original 1976 edition, presents an eclectic combination of activities gathered from parents and teachers of preschool children, with a focus on the process rather than the product of learning. Its goal is the establishment of positive experiences and sound interpersonal relationships between adults and…

  19. 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

  20. 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

  1. 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.

  2. 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…

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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…

  8. S100b counteracts effects of the neurotoxicant trimethyltin on astrocytes and microglia.

    PubMed

    Reali, Camilla; Scintu, Franca; Pillai, Rita; Donato, Rosario; Michetti, Fabrizio; Sogos, Valeria

    2005-09-01

    Central nervous system degenerative diseases are often characterized by an early, strong reaction of astrocytes and microglia. Both these cell types can play a double role, protecting neurons against degeneration through the synthesis and secretion of trophic factors or inducing degeneration through the secretion of toxic molecules. Therefore, we studied the effects of S100B and trimethyltin (TMT) on human astrocytes and microglia with two glial models, primary cultures of human fetal astrocytes and a microglia cell line. After treatment with 10(-5) M TMT, astrocytes showed morphological alterations associated with an increase in glial fibrillary acidic protein (GFAP) expression and changes in GFAP filament organization. Administration of S100B before TMT treatment prevented TMT-induced changes in morphology and GFAP expression. A decrease in inducible nitric oxide synthase expression was observed in astrocytes treated with TMT, whereas the same treatment induced iNOS expression in microglia. In both cases, S100B prevented TMT-induced changes. Tumor necrosis factor-alpha mRNA expression in astrocytes was not modified by TMT treatment, whereas it was increased in microglia cells. S100B pretreatment blocked the TMT-induced increase in TNF-alpha expression in microglia. To trace the mechanisms involved in S100B activity, the effect of BAY 11-7082, an inhibitor of nuclear factor-kappaB (NF-kappaB) activation, and of PD98059, an inhibitor of MEK-ERK1/2, were investigated. Results showed that the protective effects of S100B against TMT toxicity in astrocytes depend on NF-kappaB, but not on ERK1/2 activation. These results might help in understanding the role played by glial cells in brain injury after exposure to chemical neurotoxicants and support the view that S100B may protect brain cells in case of injury. (c) 2005 Wiley-Liss, Inc.

  9. Classical activation of microglia in CD200-deficient mice is a consequence of blood brain barrier permeability and infiltration of peripheral cells.

    PubMed

    Denieffe, Stephanie; Kelly, Ronan J; McDonald, Claire; Lyons, Anthony; Lynch, Marina A

    2013-11-01

    The interaction between CD200, expressed on several cell types, and its receptor CD200R, expressed on cells of the myeloid lineage, has been shown to be an important factor in modulating inflammation in macrophage function in several conditions including colitis and arthritis. More recently its modulatory effect on microglial activation has been identified and CD200-deficiency has been associated with increased microglial activation accompanied by increased production of inflammatory cytokines. The response of glia prepared from CD200-deficient mice to stimuli like lipopolysaccharide (LPS) is markedly greater than the response of cells prepared from wildtype mice and, consistent with this, is the recent observation that expression of Toll-like receptor (TLR)4 and signalling through NFκB are increased in microglia prepared from CD200-deficient mice. Here we show that glia from CD200-deficient mice are also more responsive to interferon-γ (IFNγ) which triggers classical activation of microglia. We investigated the effects of CD200-deficiency in vivo and report that there is an increase in expression of several markers of microglial activation including tumor necrosis factor (TNF)-α, which is a hallmark of classically-activated microglia. These changes are accompanied by increased IFNγ, and the evidence suggests that this is produced by infiltrating cells including T cells and macrophages. We propose that these cells enter the brain as a consequence of increased blood brain barrier (BBB) permeability in CD200-deficient mice and that infiltration is assisted by increased expression of the chemokines, monocyte chemotactic protein-1 (MCP-1), IFNγ-induced protein-10 (IP-10) and RANTES. This may have implications in neurodegenerative diseases where BBB permeability is compromised.

  10. 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

  11. 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.

  12. Inhibition of UDP/P2Y6 purinergic signaling prevents phagocytosis of viable neurons by activated microglia in vitro and in vivo.

    PubMed

    Neher, Jonas J; Neniskyte, Urte; Hornik, Tamara; Brown, Guy C

    2014-09-01

    Microglia activated through Toll-like receptor (TLR)-2 or -4 can cause neuronal death by phagocytosing otherwise-viable neurons-a form of cell death called "phagoptosis." UDP release from neurons has been shown to provoke microglial phagocytosis of neurons via microglial P2Y6 receptors, but whether inhibition of this process affects neuronal survival is unknown. We tested here whether inhibition of P2Y6 signaling could prevent neuronal death in inflammatory conditions, and whether UDP signaling can induce phagoptosis of stressed but viable neurons. We find that delayed neuronal loss and death in mixed neuronal/glial cultures induced by the TLR ligands lipopolysaccharide (LPS) or lipoteichoic acid was prevented by: apyrase (to degrade nucleotides), Reactive Blue 2 (to inhibit purinergic signaling), or MRS2578 (to specifically block P2Y6 receptors). In each case, inflammatory activation of microglia was not affected, and the rescued neurons remained viable for at least 7 days. Blocking P2Y6 receptors with MRS2578 also prevented phagoptosis of neurons induced by 250 nM amyloid beta 1-42, 5 μM peroxynitrite, or 50 μM 3-morpholinosydnonimine (which releases reactive oxygen and nitrogen species). Furthermore, the P2Y6 receptor agonist UDP by itself was sufficient to stimulate microglial phagocytosis and to induce rapid neuronal loss that was prevented by eliminating microglia or inhibiting phagocytosis. In vivo, injection of LPS into rat striatum induced microglial activation and delayed neuronal loss and blocking P2Y6 receptors with MRS2578 prevented this neuronal loss. Thus, blocking UDP/P2Y6 signaling is sufficient to prevent neuronal loss and death induced by a wide range of stimuli that activate microglial phagocytosis of neurons.

  13. Activated microglia mediate axoglial disruption that contributes to axonal injury in multiple sclerosis.

    PubMed

    Howell, Owain W; Rundle, Jon L; Garg, Anurag; Komada, Masayuki; Brophy, Peter J; Reynolds, Richard

    2010-10-01

    The complex manifestations of chronic multiple sclerosis (MS)are due in part to widespread axonal abnormalities that affect lesional and nonlesional areas in the central nervous system. We describe an association between microglial activation and axon/oligodendrocyte pathology at nodal and paranodal domains in normal-appearing white matter (NAWM) of MS cases and in experimental autoimmune encephalomyelitis (EAE). The extent of paranodal axoglial (neurofascin-155(+)/Caspr1(+)) disruption correlated with local 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 axoglial alterations were seen in the subcortical white matter of Parkinson disease cases and in preclinical EAE, at a time point when there is microglial activation before the infiltration of immune cells. Disruption of the axoglial unit in adjuvant-immunized animals was reversible and coincided with the resolution of microglial inflammation; paranodal damage and microglial inflammation persisted in chronic EAE. Axoglial integrity could be preserved by the administration of minocycline, which inhibited microglial activation, in actively immunized animals. These data indicate that, in MS NAWM, permanent disruption to axoglial domains in an environment of microglial inflammation is an early indicator of axonal injury that likely affects nerve conduction and may contribute to physiologic dysfunction.

  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. 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.

  16. 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

  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. 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

  19. IgM-Dependent Phagocytosis in Microglia Is Mediated by Complement Receptor 3, Not Fcα/μ Receptor.

    PubMed

    Weinstein, Jonathan R; Quan, Yi; Hanson, Josiah F; Colonna, Lucrezia; Iorga, Michael; Honda, Shin-ichiro; Shibuya, Kazuko; Shibuya, Akira; Elkon, Keith B; Möller, Thomas

    2015-12-01

    Microglia play an important role in receptor-mediated phagocytosis in the CNS. In brain abscess and other CNS infections, invading bacteria undergo opsonization with Igs or complement. Microglia recognize these opsonized pathogens by Fc or complement receptors triggering phagocytosis. In this study, we investigated the role of Fcα/μR, the less-studied receptor for IgM and IgA, in microglial phagocytosis. We showed that primary microglia, as well as N9 microglial cells, express Fcα/μR. We also showed that anti-Staphylococcus aureus IgM markedly increased the rate of microglial S. aureus phagocytosis. To unequivocally test the role of Fcα/μR in IgM-mediated phagocytosis, we performed experiments in microglia from Fcα/μR(-/-) mice. Surprisingly, we found that IgM-dependent phagocytosis of S. aureus was similar in microglia derived from wild-type or Fcα/μR(-/-) mice. We hypothesized that IgM-dependent activation of complement receptors might contribute to the IgM-mediated increase in phagocytosis. To test this, we used immunologic and genetic inactivation of complement receptor 3 components (CD11b and CD18) as well as C3. IgM-, but not IgG-mediated phagocytosis of S. aureus was reduced in wild-type microglia and macrophages following preincubation with an anti-CD11b blocking Ab. IgM-dependent phagocytosis of S. aureus was also reduced in microglia derived from CD18(-/-) and C3(-/-) mice. Taken together, our findings implicate complement receptor 3 and C3, but not Fcα/μR, in IgM-mediated phagocytosis of S. aureus by microglia.

  20. Protection of neurons and microglia against ethanol in a mouse model of fetal alcohol spectrum disorders by peroxisome proliferator-activated receptor-γ agonists.

    PubMed

    Kane, Cynthia J M; Phelan, Kevin D; Han, Lihong; Smith, Renea R; Xie, Jin; Douglas, James C; Drew, Paul D

    2011-06-01

    Fetal alcohol spectrum disorders (FASD) result from ethanol exposure to the developing fetus and are the most common cause of mental retardation in the United States. These disorders are characterized by a variety of neurodevelopmental and neurodegenerative anomalies which result in significant lifetime disabilities. Thus, novel therapies are required to limit the devastating consequences of FASD. Neuropathology associated with FASD can occur throughout the central nervous system (CNS), but is particularly well characterized in the developing cerebellum. Rodent models of FASD have previously demonstrated that both Purkinje cells and granule cells, which are the two major types of neurons in the cerebellum, are highly susceptible to the toxic effects of ethanol. The current studies demonstrate that ethanol decreases the viability of cultured cerebellar granule cells and microglial cells. Interestingly, microglia have dual functionality in the CNS. They provide trophic and protective support to neurons. However, they may also become pathologically activated and produce inflammatory molecules toxic to parenchymal cells including neurons. The findings in this study demonstrate that the peroxisome proliferator-activated receptor-γ agonists 15-deoxy-Δ12,15 prostaglandin J2 and pioglitazone protect cultured granule cells and microglia from the toxic effects of ethanol. Furthermore, investigations using a newly developed mouse model of FASD and stereological cell counting methods in the cerebellum elucidate that ethanol administration to neonates is toxic to both Purkinje cell neurons as well as microglia, and that in vivo administration of PPAR-γ agonists protects these cells. In composite, these studies suggest that PPAR-γ agonists may be effective in limiting ethanol-induced toxicity to the developing CNS.

  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. 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.

  3. 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

  4. 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.

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

    PubMed

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

    2015-11-01

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

  6. Microglia-derived interleukin-6 and leukaemia inhibitory factor promote astrocytic differentiation of neural stem/progenitor cells.

    PubMed

    Nakanishi, Masaya; Niidome, Tetsuhiro; Matsuda, Satoru; Akaike, Akinori; Kihara, Takeshi; Sugimoto, Hachiro

    2007-02-01

    Neural stem/progenitor cells (NSPCs) proliferate and differentiate depending on their intrinsic properties and local environment. It has been recognized that astrocytes promote neurogenic differentiation of NSPCs, suggesting the importance of cell-cell interactions between glial cells and NSPCs. Recent studies have demonstrated that microglia, one type of glial cells, play an important role in neurogenesis. However, little is known about how activated microglia control the proliferation and differentiation of NSPCs. In this study, we investigated the possibility that microglia-derived soluble factors regulate the behaviour of NSPCs. To this end, NSPCs and microglial cultures were obtained from rat embryonic day 16 subventricular zone (SVZ) and rat postnatal 1 day cortex, respectively, and the conditioned medium from microglia was prepared. Microglial-conditioned medium had no significant effect on the proliferation of NSPCs. In contrast, it increased the percentage of cells positive for a marker of astrocytes, glial fibrillary acidic protein (GFAP) during differentiation. The induction of astrocytic differentiation by microglial-conditioned medium was reduced by the inhibition of the Janus kinase/signal transducer and activation of transcription (JAK/STAT) and mitogen-activated protein kinase (MAPK) pathways. Furthermore, microglia-derived interleukin (IL)-6 and leukaemia inhibitory factor (LIF) were identified as essential molecules for this astrocytic differentiation using neutralizing antibodies and recombinant cytokines. Our results suggest that microglia as well as astrocytes contribute to the integrity of the local environment of NSPCs, and at least IL-6 and LIF released by activated microglia promote astrocytic differentiation of NSPCs via the activation of the JAK/STAT and MAPK pathways.

  7. Mas-related gene (Mrg) C receptors inhibit mechanical allodynia and spinal microglia activation in the early phase of neuropathic pain in rats.

    PubMed

    Wang, Dongmei; Xue, Yaping; Chen, Yajuan; Ruan, Liqin; Hong, Yanguo

    2016-04-01

    Mas-related gene (Mrg) C receptors are exclusively expressed in the trigeminal and dorsal root ganglia (DRG). However, their functional roles are poorly understood. This study was aimed to determine the effect of MrgC receptors on pain hypersensitivity in the early phase of neuropathic pain and its underlying mechanisms. Intrathecal (i.t.) administration of the selective MrgC receptor agonist bovine adrenal medulla 8-22 (BAM8-22) at 1 or 10nmol attenuated mechanical allodynia one day after L5 spinal nerve ligation (SNL) surgery. I.t. BAM8-22 (10 nmol) inhibited SNL-induced microglia activation in the spinal dorsal horn on day 2 post-SNL. The BAM8-22 treatment also abolished SNL-induced upregulation of neuronal nitric oxide synthesis (nNOS) in the dorsal root ganglia (DRG). On the other hand, SNL, but not sham, surgery reduced the expression of MrgC receptor mRNA in the injured L5 DRG without changing thier levels in the adjacent uninjured L4 or L6 DRG on day 2 following the surgery. These results suggest that the activation of MrgC receptors can relieve pain hypersensitivity by the inhibition of nNOS increase in DRG neurons and microglia activation in the spinal dorsal horn in the early time following peripheral nerve injury. This study provides evidence that MrgC receptors could be targeted as a novel therapy for neuropathic pain with limited unwanted effects.

  8. 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…

  9. 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

  10. 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

  11. Developing Geometric Thinking through Activities That Begin with Play.

    ERIC Educational Resources Information Center

    van Hiele, Pierre M.

    1999-01-01

    Rich and stimulating instruction in geometry can be provided through playful activities with mosaics such as pattern blocks or design tiles. Presents an intriguing mosaic puzzle to describe activities at various developmental levels and how the activities can help develop children's geometric thinking. (ASK)

  12. The Critical Role of Proteolytic Relay through Cathepsins B and E in the Phenotypic Change of Microglia/Macrophage.

    PubMed

    Ni, Junjun; Wu, Zhou; Peterts, Christoph; Yamamoto, Kenji; Qing, Hong; Nakanishi, Hiroshi

    2015-09-01

    Proteinase cascades are part of the basic machinery of neuronal death pathways. Neuronal cathepsin B (CatB), a typical cysteine lysosomal protease, plays a critical role in neuronal death through lysosomal leakage or excessive autophagy. On the other hand, much attention has been paid to microglial CatB in neuronal death. We herein show the critical role of proteolytic relay through microglial CatB and CatE in the polarization of microglia/macrophages in the neurotoxic phenotype, leading to hypoxia/ischemia (HI)-induced hippocampal neuronal damage in neonatal mice. HI caused extensive brain injury in neonatal wild-type mice, but not in CatB(-/-) mice. Furthermore, HI-induced polarization of microglia/macrophages in the neurotoxic phenotype followed by the neuroprotective phenotype in wild-type mice. On the other hand, microglia/macrophages exhibited only the early and transient polarization in the neuroprotective phenotype in CatB(-/-) mice. CA-074Me, a specific CatB inhibitor, significantly inhibited the neuronal death of primary cultured hippocampal neurons induced by the conditioned medium from cultured microglia polarized in the neurotoxic phenotype. Furthermore, CA-074Me prevented the activation of nuclear factor-κB (NF-κB) in cultured microglia by inhibiting autophagic inhibitor of κBα degradation following exposure to oxygen-glucose deprivation. Rather surprisingly, CatE increased the CatB expression after HI by the liberation of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) from microglia through the proteasomal pathway. A significant increase in CatB and CatE levels was found exclusively in microglia/macrophages after HI. Thus, a proteolytic relay through the early CatE/TRAIL-dependent proteosomal and late CatB-dependent autophagic pathways for NF-κB activation may play a critical role in the polarization of microglia/macrophages in the neurotoxic phenotype. Significance statement: Proteinase cascades are part of the basic

  13. Modulation of BV-2 microglia functions by novel quercetin pivaloyl ester.

    PubMed

    Mrvová, Nataša; Škandík, Martin; Kuniaková, Marcela; Račková, Lucia

    2015-11-01

    Chronic inflammation in brain plays a critical role in major neurodegenerative diseases such as Alzheimer's, Parkinson's disease, stroke or multiple sclerosis. Microglia, resident macrophages and intristinc components of CNS, appear to be main effectors in this pathological process. Quercetin, a naturally occurring flavonoid, was proven to downregulate inflammatory genes in microglia. Synthetically modified quercetin, 3'-O-(3-chloropivaloyl) quercetin (CPQ), is assumed to possess better biological availability and enhanced antioxidant properties. In the present study, antineuroinflammatory capability of the novel compound CPQ was assessed in BV-2 microglial cells. Our data show that treatment with CPQ attenuated the production of the inflammatory mediators, nitric oxide (NO) and tumour necrosis factor-α (TNF-α), in LPS-stimulated microglia somewhat more efficiently than did quercetin (p > 0.05 for CPQ vs. quercetin-treated group). Also, protein level of inducible NO synthase (iNOS) in LPS-activated BV-2 microglia was to some extent more effectively supressed by CPQ than by unmodified flavonoid. In consistence with the extent of their effects on pro-inflammatory markers, CPQ and quercetin showed down-regulation of NFκB activation. This quercetin analogue caused also a decline in BV-2 microglia proliferation with interfering with cell cycle progression (p < 0.001 for CPQ vs. quercetin-treated group). However, CPQ did not remarkably affect cell viability. In addition, CPQ showed a minor better suppression of PMA-induced generation of superoxide than did quercetin. Neither CPQ nor quercetin influenced phagocytosis of BV-2 cells. These results point to the therapeutic potential of 3'-O-(3-chloropivaloyl)quercetin (CPQ) as a novel antiinflammatory drug in neurodegenerative diseases, mediating favourable modulation of pro-inflammatory functions of microglia.

  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. 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.

  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. 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

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

    PubMed

    Koshida, Ryusuke; Oishi, Hisashi; Hamada, Michito; Takahashi, Satoru

    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.

  19. 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.

  20. α-Asarone attenuates microglia-mediated neuroinflammation by inhibiting NF kappa B activation and mitigates MPTP-induced behavioral deficits in a mouse model of Parkinson's disease.

    PubMed

    Kim, Byung-Wook; Koppula, Sushruta; Kumar, Hemant; Park, Ju-Young; Kim, Il-Woung; More, Sandeep V; Kim, In-Su; Han, Sang-Don; Kim, Si-Kwan; Yoon, Sung-Hwa; Choi, Dong-Kug

    2015-10-01

    The selective loss of dopaminergic neurons in Parkinson's disease (PD) is associated with microglial activation. Therefore, the importance of early therapeutic intervention to inhibit microglial activation would be an effective strategy to alleviate the progression of PD. α-Asarone, an active compound found in Araceae and Annonaceae plant species has been used to improve various disease conditions including central nervous system disorders. In the present study the in vitro and in vivo therapeutic effects of α-asarone isolated from the rhizome of Acorus gramineus Solander was evaluated on microglia-mediated neuroinflammation and neuroprotection. Lipopolysaccharide (LPS)-stimulated BV-2 microglial cells were used to evaluate in vitro effects. 1-methyl-4 phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced mouse model of PD was developed to study the neuroprotective effects of α-asarone in vivo. The results indicated that α-asarone significantly attenuated the LPS-stimulated increase in neuroinflammatory responses and suppressed pro-inflammatory cytokine production in BV-2 cells. Mechanistic study revealed that α-asarone inhibited the LPS-stimulated activation via regulation of nuclear factor kappa-B by blocking degradation of inhibitor kappa B-alpha signaling in BV-2 microglial cells. In in vivo studies, MPTP intoxication to mice resulted in brain microglial activation and significant behavioral deficits. Prophylactic treatment with α-asarone suppressed microglial activation and attenuated PD-like behavioral impairments as assessed by the Y-maze and pole tests. Taken together, these data demonstrate that α-asarone is a promising neuroprotective agent that should be further evaluated and developed for future prevention and treatment of microglia-mediated neuroinflammatory conditions including PD.

  1. Microglia in the TBI brain: The good, the bad, and the dysregulated.

    PubMed

    Loane, David J; Kumar, Alok

    2016-01-01

    As the major cellular component of the innate immune system in the central nervous system (CNS) and the first line of defense whenever injury or disease occurs, microglia play a critical role in neuroinflammation following a traumatic brain injury (TBI). In the injured brain microglia can produce neuroprotective factors, clear cellular debris and orchestrate neurorestorative processes that are beneficial for neurological recovery after TBI. However, microglia can also become dysregulated and can produce high levels of pro-inflammatory and cytotoxic mediators that hinder CNS repair and contribute to neuronal dysfunction and cell death. The dual role of microglial activation in promoting beneficial and detrimental effects on neurons may be accounted for by their polarization state and functional responses after injury. In this review article we discuss emerging research on microglial activation phenotypes in the context of acute brain injury, and the potential role of microglia in phenotype-specific neurorestorative processes such as neurogenesis, angiogenesis, oligodendrogenesis and regeneration. We also describe some of the known molecular mechanisms that regulate phenotype switching, and highlight new therapeutic approaches that alter microglial activation state balance to enhance long-term functional recovery after TBI. An improved understanding of the regulatory mechanisms that control microglial phenotypic shifts may advance our knowledge of post-injury recovery and repair, and provide opportunities for the development of novel therapeutic strategies for TBI.

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

    PubMed

    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.

  3. 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.

  4. 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

  5. Programmed death 1 deficiency induces the polarization of macrophages/microglia to the M1 phenotype after spinal cord injury in mice.

    PubMed

    Yao, Anhui; Liu, Fangfang; Chen, Kun; Tang, Liang; Liu, Ling; Zhang, Kun; Yu, Caiyong; Bian, Ganlan; Guo, Hongmin; Zheng, Jingjing; Cheng, Peng; Ju, Gong; Wang, Jian

    2014-07-01

    The inflammatory response following spinal cord injury (SCI) involves the activation of resident microglia and the infiltration of macrophages. Macrophages and microglia can be polarized into the classically activated proinflammatory M1 phenotype or the alternatively activated anti-inflammatory M2 phenotype. Programmed cell death 1 (PD-1) is a critical immune inhibitory receptor involved in innate and adaptive immune responses. However, whether PD-1 is involved in the modulation of macrophage/microglial polarization is unknown. In this study, the mRNA levels of pd1 gradually increased after SCI, and PD-1 protein was found in macrophages/microglia in injured spinal cord sections. PD-1 knockout (KO) mice showed poor locomotor recovery after spinal cord crushing compared with wild-type mice. M1-type macrophages/microglia accumulated in greater numbers in the injured spinal cord of PD-1-KO mice. Under polarized stimulation, induced expression of PD-1 occurred in cultured macrophages and microglia. PD-1 suppressed M1 polarization by reducing the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and promoted M2 polarization by increasing STAT6 phosphorylation. In PD-1-KO mice, the M1 response was enhanced via the activation of STAT1 and nuclear factor-kappa B. Furthermore, PD-1 played various roles in phagocytosis in macrophages and microglia. Therefore, our results suggest that PD-1 signaling plays an important role in the regulation of macrophage/microglial polarization. Thus, deregulated PD-1 signaling may induce the polarization of macrophages/microglia toward the M1 phenotype. Overall, our results provide new insights into the modulatory mechanisms of macrophage/microglial polarization, thereby possibly facilitating the development of new therapies for SCI via the regulation of macrophage/microglial polarization through PD-1 signaling.

  6. Cross-talk between the epidermal growth factor-like repeats/fibronectin 6-8 repeats domains of Tenascin-R and microglia modulates neural stem/progenitor cell proliferation and differentiation.

    PubMed

    Liao, Hong; Huang, Wenhui; Niu, Rui; Sun, Lixin; Zhang, Luyong

    2008-01-01

    Mounting evidence has demonstrated that the microenvironment of stem/progenitor cells plays an important role in their proliferation and commitment to their fate. However, it remains unclear how all elements, such as astrocytes, microglia, extracellular matrix molecules, soluble factors, and their cross-talk interactions in the microenvironments, affect neural stem/progenitor cell fate. This work explored the influences of cross-talk between Tenascin-R (TN-R) and microglia on neural stem/progenitor cell proliferation and differentiation. Our results show that microglia triggered by TN-R distinct domains EGF-like repeats (EGFL) and fibronectin 6-8 repeats (FN6-8) significantly enhanced the proliferation of neural stem/progenitor cells and also obviously induced the differentiation into neurons but not oligodendrocytes. Neurite processes of neurons generated from neural progenitor cells were promoted by both EGFL and FN6-8 domains-activated microglia. Microglia triggered by EGFL and FN6-8 secreted brain-derived neurotrophic factor (BDNF) and transforming growth factor-beta (TGF-beta); interestingly, FN6-8 could activate microglia to secrete nerve growth factor in addition to BDNF and TGF-beta, but EGFL domain could not. All these data implied that the cross-talk between TN-R distinct domains EGFL/FN6-8 and microglia promoted neural stem/progenitor cell proliferation and induced their differentiation into neurons.

  7. A Chimeric Cfh Transgene Leads to Increased Retinal Oxidative Stress, Inflammation, and Accumulation of Activated Subretinal Microglia in Mice

    PubMed Central

    Aredo, Bogale; Li, Tao; Chen, Xiao; Zhang, Kaiyan; Wang, Cynthia Xin-Zhao; Gou, Darlene; Zhao, Biren; He, Yuguang; Ufret-Vincenty, Rafael L.

    2015-01-01

    Purpose. Variants of complement factor H (Cfh) affecting short consensus repeats (SCRs) 6 to 8 increase the risk of age-related macular degeneration. Our aim was to explore the effect of expressing a Cfh variant on the in vivo susceptibility of the retina and RPE to oxidative stress and inflammation, using chimeric Cfh transgenic mice (chCfhTg). Methods. The chCfhTg and age-matched C57BL/6J (B6) mice were subjected to oxidative stress by either normal aging, or by exposure to a combination of oral hydroquinone (0.8% HQ) and increased light. Eyes were collected for immunohistochemistry of RPE–choroid flat mounts and of retinal sections, ELISA, electron microscopy, and RPE/microglia gene expression analysis. Results. Aging mice to 2 years led to an increased accumulation of basal laminar deposits, subretinal microglia/macrophages (MG/MΦ) staining for CD16 and for malondialdehyde (MDA), and MDA-modified proteins in the retina in chCfhTg compared to B6 mice. The chCfhTg mice maintained on HQ diet and increased light showed greater deposition of basal laminar deposits, more accumulation of fundus spots suggestive of MG/MΦ, and increased deposition of C3d in the sub-RPE space, compared to controls. In addition, chCfhTg mice demonstrated upregulation of NLRP3, IP-10, CD68, and TREM-2 in the RNA isolates from RPE/MG/MΦ. Conclusions. Expression of a Cfh transgene introducing a variant in SCRs 6 to 8 was sufficient to lead to increased retinal/RPE susceptibility to oxidative stress, a proinflammatory MG/MΦ phenotype, and a proinflammatory RPE/MG/MΦ gene expression profile in a transgenic mouse model. Our data suggest that altered interactions of Cfh with MDA-modified proteins may be relevant in explaining the effects of the Cfh variant. PMID:26030099

  8. 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

  9. Spatial and cellular characterization of mTORC1 activation after spinal cord injury reveals biphasic increase mainly attributed to microglia/macrophages.

    PubMed

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

    2014-11-01

    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.

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

    PubMed

    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

  12. 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.

  13. 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…

  14. Intrathecal Infusion of Hydrogen-Rich Normal Saline Attenuates Neuropathic Pain via Inhibition of Activation of Spinal Astrocytes and Microglia in Rats

    PubMed Central

    Sun, Xuejun; Xiang, Zhenghua; Yang, Liqun; Huang, Shengdong; Lu, Zhijie; Sun, Yuming; Yu, Wei-Feng

    2014-01-01

    Background Reactive oxygen and nitrogen species are key molecules that mediate neuropathic pain. Although hydrogen is an established antioxidant, its effect on chronic pain has not been characterized. This study was to investigate the efficacy and mechanisms of hydrogen-rich normal saline induced analgesia. Methodology/Principal findings In a rat model of neuropathic pain induced by L5 spinal nerve ligation (L5 SNL), intrathecal injection of hydrogen-rich normal saline relieved L5 SNL-induced mechanical allodynia and thermal hyperalgesia. Importantly, repeated administration of hydrogen-rich normal saline did not lead to tolerance. Preemptive treatment with hydrogen-rich normal saline prevented development of neuropathic pain behavior. Immunofluorochrome analysis revealed that hydrogen-rich normal saline treatment significantly attenuated L5 SNL-induced increase of 8-hydroxyguanosine immunoreactive cells in the ipsilateral spinal dorsal horn. Western blot analysis of SDS/PAGE-fractionated tyrosine-nitrated proteins showed that L5 SNL led to increased expression of tyrosine-nitrated Mn-containing superoxide dismutase (MnSOD) in the spinal cord, and hydrogen-rich normal saline administration reversed the tyrosine-nitrated MnSOD overexpression. We also showed that the analgesic effect of hydrogen-rich normal saline was associated with decreased activation of astrocytes and microglia, attenuated expression of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the spinal cord. Conclusion/Significance Intrathecal injection of hydrogen-rich normal saline produced analgesic effect in neuropathic rat. Hydrogen-rich normal saline-induced analgesia in neuropathic rats is mediated by reducing the activation of spinal astrocytes and microglia, which is induced by overproduction of hydroxyl and peroxynitrite. PMID:24857932

  15. 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.

  16. 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

  17. 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.

  18. Beyond Physical Activity: The Importance of Play and Nature-Based Play Spaces for Children's Health and Development.

    PubMed

    Herrington, Susan; Brussoni, Mariana

    2015-12-01

    The reduction of child obesity continues to be a challenge worldwide. Research indicates that playing outdoors, particularly in natural play spaces, boosts children's physical activity, potentially decreasing childhood obesity. We present evidence that natural play spaces also provide for more diverse forms of play for children of varying ages and competencies. This is crucial because play spaces designed expressly for physical activity may not increase physical activity among less active children. Moreover, when researchers only examine physical activity in play, they overlook the valuable contributions that play makes to other aspects of children's health and development. To enhance research on children and their play environments, we introduce the theory of play affordances. To assist in the creation of more natural play spaces, we describe the Seven Cs, an evidence-based approach for designing children's play spaces that promotes diverse play. We end with some preliminary insights from our current research using the Seven Cs to illustrate the connections between play, nature, and children's healthy development.

  19. Beyond Physical Activity: The Importance of Play and Nature-Based Play Spaces for Children's Health and Development.

    PubMed

    Herrington, Susan; Brussoni, Mariana

    2015-12-01

    The reduction of child obesity continues to be a challenge worldwide. Research indicates that playing outdoors, particularly in natural play spaces, boosts children's physical activity, potentially decreasing childhood obesity. We present evidence that natural play spaces also provide for more diverse forms of play for children of varying ages and competencies. This is crucial because play spaces designed expressly for physical activity may not increase physical activity among less active children. Moreover, when researchers only examine physical activity in play, they overlook the valuable contributions that play makes to other aspects of children's health and development. To enhance research on children and their play environments, we introduce the theory of play affordances. To assist in the creation of more natural play spaces, we describe the Seven Cs, an evidence-based approach for designing children's play spaces that promotes diverse play. We end with some preliminary insights from our current research using the Seven Cs to illustrate the connections between play, nature, and children's healthy development. PMID:26399254

  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. 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

  2. Endocannabinoids drive the acquisition of an alternative phenotype in microglia.

    PubMed

    Mecha, M; Feliú, A; Carrillo-Salinas, F J; Rueda-Zubiaurre, A; Ortega-Gutiérrez, S; de Sola, R García; Guaza, C

    2015-10-01

    The ability of microglia to acquire diverse states of activation, or phenotypes, reflects different features that are determinant for their contribution to homeostasis in the adult CNS, and their activity in neuroinflammation, repair or immunomodulation. Despite the widely reported immunomodulatory effects of cannabinoids in both the peripheral immune system and the CNS, less is known about how the endocannabinoid signaling system (eCBSS) influence the microglial phenotype. The general aim of the present study was to investigate the role of endocannabinoids in microglia polarization by using microglia cell cultures. We show that alternative microglia (M2a) and acquired deactivated microglia (M2c) exhibit changes in the eCB machinery that favor the selective synthesis of 2-AG and AEA, respectively. Once released, these eCBs might be able to act through CB1 and/or CB2 receptors in order to influence the acquisition of an M2 phenotype. We present three lines of evidence that the eCBSS is critical for the acquisition of the M2 phenotype: (i) M2 polarization occurs on exposure to the two main endocannabinoids 2-AG and AEA in microglia cultures; (ii) cannabinoid receptor antagonists block M2 polarization; and (iii) M2 polarization is dampened in microglia from CB2 receptor knockout mice. Taken together, these results indicate the interest of eCBSS for the regulation of microglial activation in normal and pathological conditions.

  3. A novel in vitro human microglia model: characterization of human monocyte-derived microglia.

    PubMed

    Etemad, Samar; Zamin, Rasheeda Mohd; Ruitenberg, Marc J; Filgueira, Luis

    2012-07-30

    Microglia are the innate immune cells of the central nervous system. They help maintaining physiological homeostasis and contribute significantly to inflammatory responses in the course of infection, injury and degenerative processes. To date, there is no standardized simple model available to investigate the biology of human microglia. The aim of this study was to establish a new human microglia model. For that purpose, human peripheral blood monocytes were cultured in serum free medium in the presence of M-CSF, GM-CSF, NGF and CCL2 to generate monocyte-derived microglia (M-MG). M-MG were clearly different in morphology, phenotype and function from freshly isolated monocytes, cultured monocytes in the absence of the cytokines and monocyte-derived dendritic cells (M-DC) cultured in the presence of GM-CSF and IL-4. M-MG acquired a ramified morphology with primary and secondary processes. M-MG displayed a comparable phenotype to the human microglia cell line HMC3, expressing very low levels of CD45, CD14 and HLA-DR, CD11b and CD11c; and undetectable levels of CD40, CD80 and CD83, and a distinct pattern of chemokine receptors (positive for CCR1, CCR2, CCR4, CCR5, CXCR1, CXCR3, CX3CR1; negative for CCR6 and CCR7). In comparison with M-DC, M-MG displayed lower T-lymphocyte stimulatory capacity, as well as lower phagocytosis activity. The described protocol for the generation of human monocyte-derived microglia is feasible, well standardized and reliable, as it uses well defined culture medium and recombinant cytokines, but no serum or conditioned medium. This protocol will certainly be very helpful for future studies investigating the biology and pathology of human microglia. PMID:22659341

  4. 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.

  5. 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

  6. Primary cultures of rat cortical microglia treated with nicotine increases in the expression of excitatory amino acid transporter 1 (GLAST) via the activation of the α7 nicotinic acetylcholine receptor.

    PubMed

    Morioka, N; Tokuhara, M; Nakamura, Y; Idenoshita, Y; Harano, S; Zhang, F F; Hisaoka-Nakashima, K; Nakata, Y

    2014-01-31

    Although the clearance of glutamate from the synapse under physiological conditions is performed by astrocytic glutamate transporters, their expression might be diminished under pathological conditions. Microglia glutamate transporters, however, might serve as a back-up system when astrocytic glutamate uptake is impaired, and could have a prominent neuroprotective function under pathological conditions. In the current study, the effect of nicotine, well known as a neuroprotective molecule, on the function of glutamate transporters in cultured rat cortical microglia was examined. Reverse transcription polymerase chain reaction and pharmacological approaches demonstrated that, glutamate/aspartate transporter (GLAST), not glutamate transporter 1 (GLT-1), is the major functional glutamate transporter in cultured cortical microglia. Furthermore, the α7 subunit was demonstrated to be the key subunit comprising nicotinic acetylcholine (nACh) receptors in these cells. Treatment of cortical microglia with nicotine led to a significant increase of GLAST mRNA expression and (14)C-glutamate uptake in a concentration- and time-dependent manner, which were markedly inhibited by pretreatment with methyllycaconitine, a selective α7 nACh receptor antagonist. The nicotine-induced expression of GLAST mRNA and protein is mediated through an inositol trisphosphate (IP3) and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) depend intracellular pathway, since pretreatment with either xestospongin C, an IP3 receptor antagonist, or KN-93, a CaMKII inhibitor, blocked GLAST expression. Together, these findings indicate that activation of nACh receptors, specifically those expressing the α7 subunit, on cortical microglia could be a key mechanism of the neuroprotective effect of nACh receptor ligands such as nicotine.

  7. Effects of Microglia on Neurogenesis.

    PubMed

    Sato, Kaoru

    2015-08-01

    This review summarizes and organizes the literature concerning the effects of microglia on neurogenesis, particularly focusing on the subgranular zone (SGZ) of the hippocampus and subventricular zone (SVZ) of the lateral ventricles, in which the neurogenic potential is progressively restricted during the life of the organism. A comparison of microglial roles in neurogenesis in these two regions indicates that microglia regulate neurogenesis in a temporally and spatially specific manner. Microglia may also sense signals from the surrounding environment and have regulatory effects on neurogenesis. We speculate microglia function as a hub for the information obtained from the inner and outer brain regions for regulating neurogenesis.

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

    PubMed

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

    2013-01-01

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

  9. scAAV9-VEGF prolongs the survival of transgenic ALS mice by promoting activation of M2 microglia and the PI3K/Akt pathway.

    PubMed

    Wang, Ying; Duan, Weisong; Wang, Wan; Di Wen; Liu, Yaling; Liu, Yakun; Li, Zhongyao; Hu, Haojie; Lin, Huiqian; Cui, Can; Li, Dongxiao; Dong, Hui; Li, Chunyan

    2016-10-01

    Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease that leads to paralysis and death three to five years after diagnosis in most patients. The disease is incurable, and the mechanism of motoneuron degeneration remains unknown, although research has demonstrated that activated microglia are involved in motor neuron death. Here, we used a simple method to deliver AAV9 virus by direct intrathecal injection and found that scAAV9-VEGF-165 improved the motor performance and prolonged the life span of SOD1-G93A mice. Furthermore, scAAV9-VEGF-165 activated the PI3K/Akt survival pathway and increased the level of Bcl-2, which contributed to the protection of motor neurons. Additionally, scAAV9-VEGF-165 attenuated the expression of classically activated (M1) microglial markers and enhanced the expression of alternatively activated (M2) microglial markers. Taken together, the results of our study suggest that simple, direct intrathecal injection of scAAV9-VEGF-165 may have a curative effect for ALS. PMID:27392886

  10. Selective depletion of Mac-1-expressing microglia in rat subventricular zone does not alter neurogenic response early after stroke.

    PubMed

    Heldmann, Ursula; Mine, Yutaka; Kokaia, Zaal; Ekdahl, Christine T; Lindvall, Olle

    2011-06-01

    Ischemic stroke induces migration of newly formed neuroblasts, generated by neural stem cells in the adult rat subventricular zone (SVZ), towards the injured striatum where they differentiate into mature neurons. Stroke also leads to accumulation of microglia in the SVZ but their role for neurogenesis is unclear. Here we developed a method for selective depletion of the macrophage antigen complex-1 (Mac-1)-expressing microglia population in the SVZ by intraventricular injection of the immunotoxin Mac-1-saporin in rats. We found that the vast majority of Mac-1+ cells were Iba-1+ microglia. The Mac-1+ population was heterogeneous and included both a small proliferative pool of cells, which was not affected by middle cerebral artery occlusion (MCAO), and a larger subpopulation that changed morphologically into a semi-activated state in response to the insult. This subpopulation did not increase its expression of the phagocytic marker ED1 but exhibited high levels of triggering receptor expressed on myeloid cells-2 (TREM-2), associated with alternative microglia activation. A minor portion of the SVZ Mac-1+ cells originated from the blood early after stroke, but this macrophage population became much more substantial at later stages. Almost 80% reduction of Mac-1-expressing microglia, caused by Mac-1 saporin delivered just before and at 1 week after MCAO, did not alter the numbers of newly formed neuroblasts in the striatum or their migratory distance. These findings indicate that the Mac-1-expressing microglia in the SVZ do not play a major role either for the number of neuroblasts which exit the SVZ or their migration in the striatum early following stroke.

  11. 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.

  12. 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

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

    PubMed

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

    2015-10-15

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

  14. Platelet-activating factor receptor (PAFR) plays a crucial role in experimental global cerebral ischemia and reperfusion.

    PubMed

    Toscano, Eliana Cristina de Brito; Silva, Bruno Costa; Victoria, Edna Constaza Gómez; Cardoso, Ana Clara de Souza; Miranda, Aline Silva de; Sugimoto, Michelle Adriane; Sousa, Lirlândia Pires; Carvalho, Bárbara Andrade de; Kangussu, Lucas Miranda; Silva, Daniele Gonçalves da; Rodrigues, Flávia Guimarães; Barcelos, Lucíola da Silva; Vasconcelos, Anilton César; Amaral, Flávio Almeida; Teixeira, Mauro Martins; Teixeira, Antônio Lúcio; Rachid, Milene Alvarenga

    2016-06-01

    Stroke is one of the most frequent causes of death and disability worldwide leading to a significant clinical and socioeconomic burden. Although different mechanisms are involved in the pathogenesis of stroke, inflammatory response occurs after ischemia and contributes to the expansion of brain injury. Platelet-activating factor receptor (PAF) plays crucial roles in both physiological and pathological conditions in the brain. PAF receptor (PAFR) may be expressed on cellular and nuclear membranes of various cell types, especially leukocytes, platelets, endothelial cells, neuronal cells and microglia. Herein, using mice lacking the PAFR receptor (PAFR(-/-)), we investigate a potential role for this receptor during experimental transient global cerebral ischemia and reperfusion (BCCAo). In PAFR deficiency, we observed a significant improvement in the neurological deficits, which were associated with a reduction of brain infarcted area as evaluated by triphenyltetrazolium chloride (TTC). Moreover, a decrease in the percentage of necrotic cavities areas and in the frequency of ischemic neurons was also found by employing histometric analysis. In addition, in PAFR(-/-) mice there was prevention of caspase-3 activation and decreased vascular permeability and brain edema. Decreased brain levels of the cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and the chemokine (C-X-C motif) ligand 1 (CXCL1) by ELISA were also detected in PAFR(-/-) BCCAo animals. Taken together, our results suggest that PAFR activation might be crucial for the global brain ischemia and reperfusion injury.

  15. Transient Receptor Potential Channels in Microglia: Roles in Physiology and Disease.

    PubMed

    Echeverry, Santiago; Rodriguez, María Juliana; Torres, Yolima P

    2016-10-01

    Microglia modulate the nervous system cellular environment and induce neuroprotective and neurotoxic effects. Various molecules are involved in these processes, including families of ion channels expressed in microglial cells, such as transient receptor potential (TRP) channels. TRP channels comprise a family of non-selective cation channels that can be activated by mechanical, thermal, and chemical stimuli, and which contribute to the regulation of intracellular calcium concentrations. TRP channels have been shown to be involved in cellular processes such as osmotic regulation, cytokine production, proliferation, activation, cell death, and oxidative stress responses. Given the significance of these processes in microglial activity, studies of TRP channels in microglia have focused on determining their roles in both neuroprotective and neurotoxic processes. TRP channel activity has been proposed to play an important function in neurodegenerative diseases, ischemia, inflammatory responses, and neuropathic pain. Modulation of TRP channel activity may thus be considered as a potential therapeutic strategy for the treatment of various diseases associated with alterations of the central nervous system (CNS). In this review, we describe the expression of different subfamilies of TRP channels in microglia, focusing on their physiological and pathophysiological roles, and consider their potential use as therapeutic targets in CNS diseases. PMID:27260222

  16. Transient Receptor Potential Channels in Microglia: Roles in Physiology and Disease.

    PubMed

    Echeverry, Santiago; Rodriguez, María Juliana; Torres, Yolima P

    2016-10-01

    Microglia modulate the nervous system cellular environment and induce neuroprotective and neurotoxic effects. Various molecules are involved in these processes, including families of ion channels expressed in microglial cells, such as transient receptor potential (TRP) channels. TRP channels comprise a family of non-selective cation channels that can be activated by mechanical, thermal, and chemical stimuli, and which contribute to the regulation of intracellular calcium concentrations. TRP channels have been shown to be involved in cellular processes such as osmotic regulation, cytokine production, proliferation, activation, cell death, and oxidative stress responses. Given the significance of these processes in microglial activity, studies of TRP channels in microglia have focused on determining their roles in both neuroprotective and neurotoxic processes. TRP channel activity has been proposed to play an important function in neurodegenerative diseases, ischemia, inflammatory responses, and neuropathic pain. Modulation of TRP channel activity may thus be considered as a potential therapeutic strategy for the treatment of various diseases associated with alterations of the central nervous system (CNS). In this review, we describe the expression of different subfamilies of TRP channels in microglia, focusing on their physiological and pathophysiological roles, and consider their potential use as therapeutic targets in CNS diseases.

  17. 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

  18. 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

  19. Anti-inflammatory Effects of Oxymatrine Through Inhibition of Nuclear Factor-kappa B and Mitogen-activated Protein Kinase Activation in Lipopolysaccharide-induced BV2 Microglia Cells.

    PubMed

    Dong, Xiao-Qiao; Du, Quan; Yu, Wen-Hua; Zhang, Zu-Yong; Zhu, Qiang; Che, Zhi-Hao; Chen, Feng; Wang, Hao; Chen, Jun

    2013-01-01

    Oxymatrine, a potent monosomic alkaloid extracted from Chinese herb Sophora japonica (Sophora flavescens Ait.). possesses anti-inflammatory activittyes. This study was designed to investigate the effects of oxymatrine on nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK)-dependent inflammatory responses in lipopolysaccharide (LPS)-activated microglia. In this paper, BV2 microglia were pretreated with different concentrations of oxymatrine (1, 10 and 20 μg/mL) for 30 min as followed by stimulation with LPS (1 μg/mL) for different times (30 min, 1 h, 3 h, and 6 h). Concentrations of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and interleukin-6 (IL-6) in supernatant, mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), cytosolic inhibitor of kappa B-alpha (I-κBα) and phospho- I-κBα and nuclear p65 protein levels, and the phosphorylations of MAPK molecules such as extracellular-signal-regulated kinase (ERK) 1/2, p38 MAPK and c-Jun N-terminal kinase (JNK) were determined. It was shown that oxymatrine inhibited the productions of NO, PGE2, TNF-α, IL-1β and IL-6, attenuated the mRNA levels of iNOS and COX-2, suppressed the phosphorylation of I-κBα in cytosol, decreased the nuclear levels of p65, and also blocked ERK, p38 and JNK pathway in LPS-stimulated BV2 microglial cells in a dose-dependent manner. According to the results; It is suggested that oxymatrine may attenuate inflammatory responses of microglia and could be potentially useful in modulation of inflammatory status in the brain disorders. PMID:24250585

  20. 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

  1. 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

  2. A role of fluoride on free radical generation and oxidative stress in BV-2 microglia cells.

    PubMed

    Shuhua, Xi; Ziyou, Liu; Ling, Yan; Fei, Wang; Sun, Guifan

    2012-01-01

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

  3. A Friend in Need may not be a Friend Indeed: Role of Microglia in Neurodegenerative Diseases.

    PubMed

    Kaushik, D K; Basu, A

    2013-09-19

    Inflammation plays a critical role in the progression of neurodegenerative diseases. Microglia are the resident macrophages of the central nervous system (CNS) which actively take part in the neuronal development of CNS and are involved in clearance of pathogens as well as cellular debris from the system upon insult to this organization. Chronic activation of microglia in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) as well as inflammatory conditions of CNS such as multiple sclerosis (MS) results in overall upregulation of pro-inflammatory cytokines and chemokines in the brain parenchyma. This compromises the neuronal health which further activates microglia by releasing death associated molecules such as neuromelanin, Aβ peptides and cellular debris at the lesion site thereby forming a vicious cycle of disease advancement. Targeting microglial activation has proven to be a viable option in the treatment of inflammation related neurodegenerative diseases. This review will discuss the central position of inflammation and therapeutic strategies aiming to alleviate disease progression in some of the important inflammatory conditions of CNS.

  4. A friend in need may not be a friend indeed: role of microglia in neurodegenerative diseases.

    PubMed

    Kaushik, Deepak Kumar; Basu, Anirban

    2013-09-01

    Inflammation plays a critical role in the progression of neurodegenerative diseases. Microglia are the resident macrophages of the central nervous system (CNS) which actively take part in the neuronal development of CNS and are involved in clearance of pathogens as well as cellular debris from the system upon insult to this organization. Chronic activation of microglia in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) as well as inflammatory conditions of CNS such as multiple sclerosis (MS) results in overall upregulation of pro-inflammatory cytokines and chemokines in the brain parenchyma. This compromises the neuronal health which further activates microglia by releasing death associated molecules such as neuromelanin, Aβ peptides and cellular debris at the lesion site thereby forming a vicious cycle of disease advancement. Targeting microglial activation has proven to be a viable option in the treatment of inflammation related neurodegenerative diseases. This review will discuss the central position of inflammation and therapeutic strategies aiming to alleviate disease progression in some of the important inflammatory conditions of CNS.

  5. Retinal microglia: just bystander or target for therapy?

    PubMed

    Karlstetter, Marcus; Scholz, Rebecca; Rutar, Matt; Wong, Wai T; Provis, Jan M; Langmann, Thomas

    2015-03-01

    Resident microglial cells can be regarded as the immunological watchdogs of the brain and the retina. They are active sensors of their neuronal microenvironment and rapidly respond to various insults with a morphological and functional transformation into reactive phagocytes. There is strong evidence from animal models and in situ analyses of human tissue that microglial reactivity is a common hallmark of various retinal degenerative and inflammatory diseases. These include rare hereditary retinopathies such as retinitis pigmentosa and X-linked juvenile retinoschisis but also comprise more common multifactorial retinal diseases such as age-related macular degeneration, diabetic retinopathy, glaucoma, and uveitis as well as neurological disorders with ocular manifestation. In this review, we describe how microglial function is kept in balance under normal conditions by cross-talk with other retinal cells and summarize how microglia respond to different forms of retinal injury. In addition, we present the concept that microglia play a key role in local regulation of complement in the retina and specify aspects of microglial aging relevant for chronic inflammatory processes in the retina. We conclude that this resident immune cell of the retina cannot be simply regarded as bystander of disease but may instead be a potential therapeutic target to be modulated in the treatment of degenerative and inflammatory diseases of the retina.

  6. 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.

  7. Phytoestrogens mediated anti-inflammatory effect through suppression of IRF-1 and pSTAT1 expressions in lipopolysaccharide-activated microglia.

    PubMed

    Jantaratnotai, Nattinee; Utaisincharoen, Pongsak; Sanvarinda, Pimtip; Thampithak, Anusorn; Sanvarinda, Yupin

    2013-10-01

    Microglial activation has been implicated in various neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and HIV encephalopathy. Phytoestrogens have been shown to be neuroprotective in neurotoxicity models; however, their effect on microglia has not been well established. In the current study, we report that the soy phytoestrogens, genistein, daidzein, and coumestrol, decreased nitric oxide (NO) production induced by lipopolysaccharide (LPS) in the rat microglial cell line (HAPI). The levels of inducible NO synthase (iNOS) mRNA and protein expression were also reduced. Transcription factors known to govern iNOS expression including interferon regulatory factor-1 (IRF-1) and phosphorylated STAT1 were down regulated. These observations explain, at least in part, the inhibitory effect of phytoestrogens on NO production. The levels of monocyte chemoattractant protein-1 and interleukin-6 mRNA, proinflammatory chemokine and cytokine associated with various neurological disorders, were also reduced following LPS stimulation when HAPI cells were pretreated with phytoestrogens. Hence, genistein, daidzein, and coumestrol could serve as anti-inflammatory agents and may have beneficial effects in the treatment of neurodegenerative diseases.

  8. Estrogen anti-inflammatory activity in brain: a therapeutic opportunity for menopause and neurodegenerative diseases

    PubMed Central

    Vegeto, Elisabetta; Benedusi, Valeria; Maggi, Adriana

    2008-01-01

    Recent studies highlight the prominent role played by estrogens in protecting the central nervous system (CNS) against the noxious consequences of a chronic inflammatory reaction. The neurodegenerative process of several CNS diseases, including Multiple Sclerosis, Alzheimer’s and Parkinson’s Diseases, is associated with the activation of microglia cells, which drive the resident inflammatory response. Chronically stimulated during neurodegeneration, microglia cells are thought to provide detrimental effects on surrounding neurons. The inhibitory activity of estrogens on neuroinflammation and specifically on microglia might thus be considered as a beneficial therapeutic opportunity for delaying the onset or progression of neurodegenerative diseases; in addition, understanding the peculiar activity of this female hormone on inflammatory signalling pathways will possibly lead to the development of selected anti-inflammatory molecules. This review summarises the evidence for the involvement of microglia in neuroinflammation and the anti-inflammatory activity played by estrogens specifically in microglia. PMID:18522863

  9. 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.

  10. 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

  11. 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

  12. HIV-infected microglia mediate cathepsin B-induced neurotoxicity.

    PubMed

    Zenón, Frances; Cantres-Rosario, Yisel; Adiga, Radhika; Gonzalez, Mariangeline; Rodriguez-Franco, Eillen; Langford, Dianne; Melendez, Loyda M

    2015-10-01

    HIV-1-infected mononuclear phagocytes release soluble factors that affect the homeostasis in tissue. HIV-1 can prompt metabolic encephalopathy with the addition of neuronal dysfunction and apoptosis. Recently, we reported that HIV-1 enhances the expression and secretion of bioactive cathepsin B in monocyte-derived macrophages, ultimately contributing to neuronal apoptosis. In this research, we asked if microglia respond to HIV infection similarly by modifying the expression, secretion, and neurotoxic potential of cathepsin B and determined the in vivo relevance of these findings. HIV-1ADA-infected human primary microglia and CHME-5 microglia cell line were assessed for expression and activity of cathepsin B, its inhibitors, cystatins B and C, and the neurotoxicity associated with these changes. Human primary neurons were exposed to supernatants from HIV-infected and uninfected microglia in the presence of cathepsin B inhibitors and apoptosis was assessed by TUNEL. Microglial expression of cathepsin B was validated in brain tissue from HIV encephalitis (HIVE) patients. HIV-infected microglia secreted significantly greater levels of cathepsin B, cystatin B, and cystatin C compared to uninfected cells. Increased apoptosis was observed in neurons exposed to supernatants from HIV-1 infected microglia at day 12 post-infection. The cathepsin B inhibitor CA-074 and cathepsin B antibody prevented neuronal apoptosis. Increased microglia-derived cathepsin B, cystatin B, and cystatin C and caspase-3+ neurons were detected in HIVE brains compared to controls. Our results suggest that HIV-1-induced cathepsin B production in microglia contributes to neuronal apoptosis and may be an important factor in neuronal death associated with HIVE.

  13. 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.

  14. Direct anti-inflammatory effects of angiotensin-(1-7) on microglia.

    PubMed

    Liu, Meng; Shi, Peng; Sumners, Colin

    2016-01-01

    Much evidence indicates that pro-inflammatory effects of the renin-angiotensin system within the hypothalamus, including microglial activation and production of pro-inflammatory cytokines, play a role in chronic neurogenic hypertension. Our objective here was to examine whether angiotensin-(1-7) [Ang-(1-7)], a protective component of the renin-angiotensin system, exerts direct actions at microglia to counteract these pro-inflammatory effects. Mas, the Ang-(1-7) receptor, was shown to be present on cultured hypothalamic microglia. Treatment of these cells with Ang-(1-7) (100-1000 nM, 3-12 h) elicited significant decreases in basal levels of mRNAs for the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumor-necrosis factor α (TNFα) and of the microglia-macrophage marker CD11b, and increases in basal levels of the anti-inflammatory cytokine interleukin-10. Incubation of microglial cultures with (pro)renin (PRO) (10-50 nM; 6 h) elicited significant increases in mRNAs for IL-1β, TNFα and CD11b. The effects of PRO (10 nM) on IL-1β and TNFα mRNAs, and TNFα protein, were significantly attenuated by co-treatment with Ang-(1-7) (100 nM). Lastly, these actions of Ang-(1-7) were abolished by the Mas antagonist A-779, and were associated with reductions in NF-κB subunit expression. Collectively, these data provide the first evidence that Ang-(1-7) can exert direct effects at microglia to lower baseline and counteract PRO-induced increases in pro-inflammatory cytokines. Renin-Angiotensin system mediated microglial activation and pro-inflammatory cytokine production within the hypothalamus are components of the chronic neuroinflammation associated with 'neurogenic' hypertension. We demonstrated that angiotension-(1-7) acting via its receptor Mas on hypothalamic microglia lessens baseline and (pro)renin-induced increases in pro-inflammatory cytokine production by these cells. This is the first evidence that angiotensin-(1-7) has direct anti-inflammatory effects

  15. 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.

  16. Effects of Microglia on Neurogenesis

    PubMed Central

    2015-01-01

    This review summarizes and organizes the literature concerning the effects of microglia on neurogenesis, particularly focusing on the subgranular zone (SGZ) of the hippocampus and subventricular zone (SVZ) of the lateral ventricles, in which the neurogenic potential is progressively restricted during the life of the organism. A comparison of microglial roles in neurogenesis in these two regions indicates that microglia regulate neurogenesis in a temporally and spatially specific manner. Microglia may also sense signals from the surrounding environment and have regulatory effects on neurogenesis. We speculate microglia function as a hub for the information obtained from the inner and outer brain regions for regulating neurogenesis. GLIA 2015;63:1394–1405 PMID:26010551

  17. Parents' Perceptions of Preschool Activities: Exploring Outdoor Play

    ERIC Educational Resources Information Center

    Jayasuriya, Avanthi; Williams, Marcia; Edwards, Todd; Tandon, Pooja

    2016-01-01

    Research Findings: Outdoor play is important for children's health and development, yet many preschool-age children in child care settings do not receive the recommended 60 min/day of outdoor play. Child care providers have previously described parent-related barriers to increasing outdoor playtime, including parents not providing appropriate…

  18. 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.

  19. 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.

  20. Embryonic stem cell-derived neural stem cells fuse with microglia and mature neurons.

    PubMed

    Cusulin, Carlo; Monni, Emanuela; Ahlenius, Henrik; Wood, James; Brune, Jan Claas; Lindvall, Olle; Kokaia, Zaal

    2012-12-01

    Transplantation of neural stem cells (NSCs) is a novel strategy to restore function in the diseased brain, acting through multiple mechanisms, for example, neuronal replacement, neuroprotection, and modulation of inflammation. Whether transplanted NSCs can operate by fusing with microglial cells or mature neurons is largely unknown. Here, we have studied the interaction of a mouse embryonic stem cell-derived neural stem (NS) cell line with rat and mouse microglia and neurons in vitro and in vivo. We show that NS cells spontaneously fuse with cocultured cortical neurons, and that this process requires the presence of microglia. Our in vitro data indicate that the NS cells can first fuse with microglia and then with neurons. The fused NS/microglial cells express markers and retain genetic and functional characteristics of both parental cell types, being able to respond to microglia-specific stimuli (LPS and IL-4/IL-13) and to differentiate to neurons and astrocytes. The NS cells fuse with microglia, at least partly, through interaction between phosphatidylserine exposed on the surface of NS cells and CD36 receptor on microglia. Transplantation of NS cells into rodent cortex results in fusion with mature pyramidal neurons, which often carry two nuclei, a process probably mediated by microglia. The fusogenic role of microglia could be even more important after NSC transplantation into brains affected by neurodegenerative diseases associated with microglia activation. It remains to be elucidated how the occurrence of the fused cells will influence the functional outcome after NSC transplantation in the diseased brain.

  1. 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...

  2. 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

  3. ME-03BONE MARROW DERIVED MICROGLIA AND THEIR FUNCTION WITHIN TUMOR MICROENVIRONMENT

    PubMed Central

    Burrell, Kelly; Singh, Sanjay; Agnihotri, Sameer; Hill, Richard; Aldape, Kenneth; Zadeh, Gelareh

    2014-01-01

    We have previously demonstrated that BMDC are recruited to Glioblastoma Multiforme (GBM), in a highly tumor-growth and region-dependent pattern, demonstrating that the majority of BMDCs differentiate into inflammatory cells, MAC3 + , and CD11b+ IBA1+ microglia-like cells. The majority of microglia seen in GBM microenvironment are derived from the BMDC rather than being resident brain microglia. The role of microglial cells in GBMs remains unknown, with evidence supporting both an anti- and pro- tumorgenic function. In this study we aimed to understand the contribution of microglia to GBM growth and tumor vascularity. Chimeric mice with reconstituted green-fluorescent bone marrow were used to create intracranial GBM xenografts, by implanting red fluorescent glioma stem cells or U87 into the frontal lobe. Using a known inhibitor of microglial activation, minocycline, we show that treatment with this agent increased tumor cell growth and invasiveness and reduced animal survival compared to controls. We show that Minocycline decreases activation of microglia, inhibits the phagocytic activity of microglia in GBMs and decreases the perivascular localization of microglia. The mRNA expression profile of microglia isolated from the GBM microenvironment showed, through Ingenuity Pathway Analysis (IPA), a loss of engulfment and migration of cells and phaocytotic pathways in BM-derived microglia, additionally we see a reorganization of cytoskeletal pathways leading to an increase in the migration and invasiveness of GBM cells following treatment with Minocycline. We also have preliminary data to suggest that this property of Minocycline is dependent on VEGF levels, where in the context of low VEGF Minocycline does not provide a significant anti-angiogenic role. We demonstrate that microglia in GBM microenvironment, are primarily recruited and differentiated from the BM and not resident, and that these cells have an anti-tumorgenic functions, and inhibition of the activated

  4. Amyloid-β42 protofibrils are internalized by microglia more extensively than monomers.

    PubMed

    Gouwens, Lisa K; Makoni, Nyasha J; Rogers, Victoria A; Nichols, Michael R

    2016-10-01

    One pathological hallmark of Alzheimer's disease (AD) is the accumulation of amyloid-β peptide (Aβ) in the affected brain. While there are numerous deleterious effects of Aβ accumulation, there is general agreement that a sustained inflammatory response to aggregated Aβ contributes to progressive neurodegeneration in AD and microglial cells play a significant role in this process. Our laboratory and others have shown that small soluble aggregates of Aβ activate a microglia-mediated inflammatory response. One component of the response involves internalization of extracellular Aβ, and this process is likely very sensitive to Aβ structure. In this study we analyzed the proclivity of microglia for internalization of Aβ42 monomers and protofibrils using fluorescently-labeled Aβ. Both Aβ42 species were labeled directly via amino linkage with an Alexa Fluor 488 tetrafluorophenyl ester (AF488-TFP) and then isolated individually by chromatography. Aβ42 protofibrils retained their size and morphological properties after labeling but monomers had a much higher stoichiometry of labeling compared to protofibrils. Primary murine microglia internalized AF488-Aβ42 protofibrils rapidly and in significant amounts compared to AF488-Aβ42 monomers. Microglial internalization of protofibrils was dependent on time and concentration, and corresponded with tumor necrosis factor α secretion. In competition studies, unlabeled Aβ42 protofibril internalization, detected by immunostaining, did not diminish AF488-protofibril uptake. Internalized AF488-Aβ42 protofibrils were found widely dispersed in the cytosol with some lysosomal accumulation but little degradation. These studies highlight the sensitivity that microglia exhibit to Aβ structure in the internalization process and emphasize their affinity for soluble Aβ protofibrils. PMID:27531183

  5. Postmortem Adult Human Microglia Proliferate in Culture to High Passage and Maintain Their Response to Amyloid-β

    PubMed Central

    Guo, Ling; Rezvanian, Aras; Kukreja, Lokesh; Hoveydai, Ramez; Bigio, Eileen H.; Mesulam, M.-Marsel; El Khoury, Joseph; Geula, Changiz

    2016-01-01

    Microglia are immune cells of the brain that display a range of functions. Most of our knowledge about microglia biology and function is based on cells from the rodent brain. Species variation in the complexity of the brain and differences in microglia response in the primate when compared with the rodent, require use of adult human microglia in studies of microglia biology. While methods exist for isolation of microglia from postmortem human brains, none allow culturing cells to high passage. Thus cells from the same case could not be used in parallel studies and multiple conditions. Here we report a method, which includes use of growth factors such as granulocyte macrophage colony stimulating factor, for successful culturing of adult human microglia from postmortem human brains up to 28 passages without significant loss of proliferation. Such cultures maintained their phenotype, including uptake of the scavenger receptor ligand acetylated low density lipoprotein and response to the amyloid-β peptide, and were used to extend in vivo studies in the primate brain demonstrating that inhibition of microglia activation protects neurons from amyloid-β toxicity. Significantly, microglia cultured from brains with pathologically confirmed Alzheimer’s disease displayed the same characteristics as microglia cultured from normal aged brains. The method described here provides the scientific community with a new and reliable tool for mechanistic studies of human microglia function in health from childhood to old age, and in disease, enhancing the relevance of the findings to the human brain and neurodegenerative conditions. PMID:27567845

  6. 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…

  7. 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.…

  8. 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…

  9. 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.

  10. 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

  11. HIV-infected microglia mediate cathepsin B induced neurotoxicity

    PubMed Central

    Zenón, Frances; Cantres-Rosario, Yisel; Adiga, Radhika; Gonzalez, Mariangeline; Rodriguez-Franco, Eillen; Langford, Dianne; Melendez, Loyda M.

    2015-01-01

    BACKGROUND HIV-1-infected mononuclear phagocytes release soluble factors that affect the homeostasis in tissue. HIV-1 can prompt metabolic encephalopathy with the addition of neuronal dysfunction and apoptosis. Recently, we reported that HIV-1 enhances the expression and secretion of bioactive cathepsin B in monocyte-derived macrophages, ultimately contributing to neuronal apoptosis. In this research, we request if microglia respond to HIV infection similarly by modifying the expression, secretion, neurotoxic potential of cathepsin B and the in vivo relevance of these findings. METHODS HIV-ADA infected human primary microglia and CHME-5 were assessed for expression and activity of cathepsin B, its inhibitors, cystatins B and C, and neurotoxicity associated with these changes. Human primary neurons were exposed to supernatants from HIV-infected and uninfected microglia in the presence of cathepsin B inhibitors and apoptosis was assessed by TUNEL. Microglial expression of cathepsin B was validated in brain tissue from HIVE patients. RESULTS HIV-infected microglia secreted significantly greater levels of cathepsin B, cystatin B, and cystatin C compared to uninfected cells. Increased apoptosis was observed in neurons exposed to supernatants from HIV-1 infected microglia at days 12 post-infection. The cathepsin B inhibitor CA-074 and cathepsin B antibody prevented neuronal apoptosis. Increased microglia-derived cathepsin B, cystatin B, and cystatin C and caspase-3+ neurons were detected in HIVE brains compared to controls. CONCLUSIONS Our results suggest that HIV-1-induced cathepsin B production in microglia contributes to neuronal apoptosis and may be an important factor in neuronal death associated with HIVE. PMID:26092112

  12. 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

  13. 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

  14. Recombinant adeno-associated viral (rAAV) vectors mediate efficient gene transduction in cultured neonatal and adult microglia.

    PubMed

    Su, Wei; Kang, John; Sopher, Bryce; Gillespie, James; Aloi, Macarena S; Odom, Guy L; Hopkins, Stephanie; Case, Amanda; Wang, David B; Chamberlain, Jeffrey S; Garden, Gwenn A

    2016-01-01

    Microglia are a specialized population of myeloid cells that mediate CNS innate immune responses. Efforts to identify the cellular and molecular mechanisms that regulate microglia behaviors have been hampered by the lack of effective tools for manipulating gene expression. Cultured microglia are refractory to most chemical and electrical transfection methods, yielding little or no gene delivery and causing toxicity and/or inflammatory activation. Recombinant adeno-associated viral (rAAVs) vectors are non-enveloped, single-stranded DNA vectors commonly used to transduce many primary cell types and tissues. In this study, we evaluated the feasibility and efficiency of utilizing rAAV serotype 2 (rAAV2) to modulate gene expression in cultured microglia. rAAV2 yields high transduction and causes minimal toxicity or inflammatory response in both neonatal and adult microglia. To demonstrate that rAAV transduction can induce functional protein expression, we used rAAV2 expressing Cre recombinase to successfully excise a LoxP-flanked miR155 gene in cultured microglia. We further evaluated rAAV serotypes 5, 6, 8, and 9, and observed that all efficiently transduced cultured microglia to varying degrees of success and caused little or no alteration in inflammatory gene expression. These results provide strong encouragement for the application of rAAV-mediated gene expression in microglia for mechanistic and therapeutic purposes. Neonatal microglia are functionally distinct from adult microglia, although the majority of in vitro studies utilize rodent neonatal microglia cultures because of difficulties of culturing adult cells. In addition, cultured microglia are refractory to most methods for modifying gene expression. Here, we developed a novel protocol for culturing adult microglia and evaluated the feasibility and efficiency of utilizing Recombinant Adeno-Associated Virus (rAAV) to modulate gene expression in cultured microglia.

  15. Transcription factor IRF1 is responsible for IRF8-mediated IL-1β expression in reactive microglia.

    PubMed

    Masuda, Takahiro; Iwamoto, Shosuke; Mikuriya, Satsuki; Tozaki-Saitoh, Hidetoshi; Tamura, Tomohiko; Tsuda, Makoto; Inoue, Kazuhide

    2015-08-01

    Interferon regulatory factor-8 (IRF8) plays a crucial role in the transformation of microglia to a reactive state by regulating the expression of various genes. In the present study, we show that IRF1 is required for IRF8-induced gene expression in microglia. Peripheral nerve injury induced IRF1 gene upregulation in the spinal microglia in an IRF8-dependent manner. IRF8 transduction in cultured microglia induced de novo gene expression of IRF1. Importantly, knockdown of the IRF1 gene in IRF8-transduced microglia prevented upregulation of interleukin-1β (IL-1β). Therefore, our findings suggest that expression of IL-1β is dependent on IRF1 in IRF8-expressing reactive microglia.

  16. 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

  17. 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.

  18. "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…

  19. 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…

  20. 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…

  1. Online-offline activities and game-playing behaviors of avatars in a massive multiplayer online role-playing game

    NASA Astrophysics Data System (ADS)

    Jiang, Zhi-Qiang; Zhou, Wei-Xing; Tan, Qun-Zhao

    2009-11-01

    Massive multiplayer online role-playing games (MMORPGs) are very popular in China, which provides a potential platform for scientific research. We study the online-offline activities of avatars in an MMORPG to understand their game-playing behavior. The statistical analysis unveils that the active avatars can be classified into three types. The avatars of the first type are owned by game cheaters who go online and offline in preset time intervals with the online duration distributions dominated by pulses. The second type of avatars is characterized by a Weibull distribution in the online durations, which is confirmed by statistical tests. The distributions of online durations of the remaining individual avatars differ from the above two types and cannot be described by a simple form. These findings have potential applications in the game industry.

  2. 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

  3. Nurr1 expression is modified by inflammation in microglia

    PubMed Central

    Lallier, Scott W.; Graf, Amanda E.; Waidyarante, Gavisha R.

    2016-01-01

    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

  4. The relation between α-synuclein and microglia in Parkinson's disease: Recent developments.

    PubMed

    Sanchez-Guajardo, V; Tentillier, N; Romero-Ramos, M

    2015-08-27

    Recent research suggests a complex role for microglia not only in Parkinson's disease but in other disorders involving alpha-synuclein aggregation, such as multiple system atrophy. In these neurodegenerative processes, the activation of microglia is a common pathological finding, which disturbs the homeostasis of the neuronal environment otherwise maintained, among others, by microglia. The term activation comprises any deviation from what otherwise is considered normal microglia status, including cellular abundance, morphology or protein expression. The microglial response during disease will sustain survival or otherwise promote cell degeneration. The novel concepts of alpha-synuclein being released and uptaken by neighboring cells, and their importance in disease progression, positions microglia as the main cell that can clear and handle alpha-synuclein efficiently. Microglia's behavior will therefore be a determinant on the disease's progression. For this reason we believe that the better understanding of microglia's response to alpha-synuclein pathological accumulation across brain areas and disease stages is essential to develop novel therapeutic tools for Parkinson's disease and other alpha-synucleinopathies. In this review we will revise the most recent findings and developments with regard to alpha-synuclein and microglia in Parkinson's disease.

  5. Reactive microglia and macrophage facilitate the formation of Müller glia-derived retinal progenitors.

    PubMed

    Fischer, Andy J; Zelinka, Christopher; Gallina, Donika; Scott, Melissa A; Todd, Levi

    2014-10-01

    In retinas where Müller glia have been stimulated to become progenitor cells, reactive microglia are always present. Thus, we investigated how the activation or ablation of microglia/macrophage influences the formation of Müller glia-derived progenitor cells (MGPCs) in the retina in vivo. Intraocular injections of the Interleukin-6 (IL6) stimulated the reactivity of microglia/macrophage, whereas other types of retinal glia appear largely unaffected. In acutely damaged retinas where all of the retinal microglia/macrophage were ablated, the formation of proliferating MGPCs was greatly diminished. With the microglia ablated in damaged retinas, levels of Notch and related genes were unchanged or increased, whereas levels of ascl1a, TNFα, IL1β, complement component 3 (C3) and C3a receptor were significantly reduced. In the absence of retinal damage, the combination of insulin and Fibroblast growth factor 2 (FGF2) failed to stimulate the formation of MGPCs when the microglia/macrophage were ablated. In addition, intraocular injections of IL6 and FGF2 stimulated the formation of MGPCs in the absence of retinal damage, and this generation of MGPCs was blocked when the microglia/macrophage were absent. We conclude that the activation of microglia and/or infiltrating macrophage contributes to the formation of proliferating MGPCs, and these effects may be mediated by components of the complement system and inflammatory cytokines.

  6. 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…

  7. Selective Depletion of Microglia from Cerebellar Granule Cell Cultures Using L-leucine Methyl Ester.

    PubMed

    Jebelli, Joseph; Piers, Thomas; Pocock, Jennifer

    2015-01-01

    Microglia, the resident immunocompetent cells of the CNS, play multifaceted roles in modulating and controlling neuronal function, as well as mediating innate immunity. Primary rodent cell culture models have greatly advanced our understanding of neuronal-glial interactions, but only recently have methods to specifically eliminate microglia from mixed cultures been utilized. One such technique - described here - is the use of L-leucine methyl ester, a lysomotropic agent that is internalized by macrophages and microglia, wherein it causes lysosomal disruption and subsequent apoptosis(13,14). Experiments using L-leucine methyl ester have the power to identify the contribution of microglia to the surrounding cellular environment under diverse culture conditions. Using a protocol optimized in our laboratory, we describe how to eliminate microglia from P5 rodent cerebellar granule cell culture. This approach allows one to assess the relative impact of microglia on experimental data, as well as determine whether microglia are playing a neuroprotective or neurotoxic role in culture models of neurological conditions, such as stroke, Alzheimer's or Parkinson's disease.

  8. Microglia in Close Vicinity of Glioma Cells: Correlation Between Phenotype and Metabolic Alterations

    PubMed Central

    Voisin, Pierre; Bouchaud, Véronique; Merle, Michel; Diolez, Philippe; Duffy, Laura; Flint, Kristian; Franconi, Jean-Michel; Bouzier-Sore, Anne-Karine

    2010-01-01

    Microglia are immune cells within the central nervous system. In brain-developing tumors, gliomas are able to silence the defense and immune functions of microglia, a phenomenon which strongly contributes to tumor progression and treatment resistance. Being activated and highly motile, microglia infiltrate tumors and secrete macrophagic chemoattractant factors. Thereafter, the tumor cells shut down their immune properties and stimulate the microglia to release tumor growth-promoting factors. The result of such modulation is that a kind of symbiosis occurs between microglia and tumor cells, in favor of tumor growth. However, little is known about microglial phenotype and metabolic modifications in a tumoral environment. Co-cultures were performed using CHME5 microglia cells grown on collagen beads or on coverslips and placed on monolayer of C6 cells, limiting cell/cell contacts. Phagocytic behavior and expression of macrophagic and cytoskeleton markers were monitored. Respiratory properties and energetic metabolism were also studied with regard to the activated phenotype of microglia. In co-cultures, transitory modifications of microglial morphology and metabolism were observed linked to a concomitant transitory increase of phagocytic properties. Therefore, after 1 h of co-culture, microglia were activated but when longer in contact with tumor cells, phagocytic properties appear silenced. Like the behavior of the phenotype, microglial respiration showed a transitory readjustment although the mitochondria maintained their perinuclear relocation. Nevertheless, the energetic metabolism of the microglia was altered, suggesting a new energetic steady state. The results clearly indicate that like the depressed immune properties, the macrophagic and metabolic status of the microglia is quickly driven by the glioma environment, despite short initial phagocytic activation. Such findings question the possible contribution of diffusible tumor factors to the microglial

  9. 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

  10. 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

  11. 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…

  12. 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…

  13. 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

  14. Hypothesis: are neoplastic macrophages/microglia present in glioblastoma multiforme?

    PubMed Central

    Huysentruyt, Leanne C; Akgoc, Zeynep; Seyfried, Thomas N

    2011-01-01

    Most malignant brain tumours contain various numbers of cells with characteristics of activated or dysmorphic macrophages/microglia. These cells are generally considered part of the tumour stroma and are often described as TAM (tumour-associated macrophages). These types of cells are thought to either enhance or inhibit brain tumour progression. Recent evidence indicates that neoplastic cells with macrophage characteristics are found in numerous metastatic cancers of non-CNS (central nervous system) origin. Evidence is presented here suggesting that subpopulations of cells within human gliomas, specifically GBM (glioblastoma multiforme), are neoplastic macrophages/microglia. These cells are thought to arise following mitochondrial damage in fusion hybrids between neoplastic stem cells and macrophages/microglia. PMID:21834792

  15. 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

  16. Astrocyte-microglia cooperation in the expression of a pro-inflammatory phenotype.

    PubMed

    Barbierato, Massimo; Facci, Laura; Argentini, Carla; Marinelli, Carla; Skaper, Stephen D; Giusti, Pietro

    2013-08-01

    Glial cells not only serve supportive and nutritive roles for neurons, but also respond to protracted stress and insults by up-regulating inflammatory processes. The complexity of studying glial activation in vivo has led to the widespread adoption of in vitro approaches, for example the use of the bacterial toxin lipopolysaccharide (LPS, a ligand for toll-like receptor 4 (TLR4)) as an experimental model of glial activation. Astrocyte cultures frequently contain minor numbers of microglia, which can complicate interpretation of responses. In the present study, enriched (≤5% microglia) astrocytes cultured from neonatal rat cortex and spinal cord were treated with the lysosomotropic agent L-leucyl-L-leucine methyl ester to eliminate residual microglia, as confirmed by loss of microglia-specific marker genes. L-Leucyl-L-leucine methyl ester treatment led to a loss of LPS responsiveness, in terms of nitric oxide and cytokine gene up-regulation and mediator (pro-inflammatory cytokines, nitric oxide) output into the culture medium. Surprisingly, when astrocyte/microglia co-cultures were then reconstituted by adding defined numbers of purified microglia to microglia-depleted astrocytes, the LPS-induced up-regulation of pro-inflammatory gene and mediator output far exceeded that observed from cultures containing the same numbers of microglia only. Similar behaviors were found when examining interleukin-1β release caused by activation of the purinergic P2X7 receptor. Given that astrocytes greatly outnumber microglia in the central nervous system, these data suggest that a similar interaction between microglia and astrocytes in vivo may be an important element in the evolution of an inflammatory pathology.

  17. 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)

  18. 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

  19. 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.

  20. Complement and microglia mediate early synapse loss in Alzheimer mouse models.

    PubMed

    Hong, Soyon; Beja-Glasser, Victoria F; Nfonoyim, Bianca M; Frouin, Arnaud; Li, Shaomin; Ramakrishnan, Saranya; Merry, Katherine M; Shi, Qiaoqiao; Rosenthal, Arnon; Barres, Ben A; Lemere, Cynthia A; Selkoe, Dennis J; Stevens, Beth

    2016-05-01

    Synapse loss in Alzheimer's disease (AD) correlates with cognitive decline. Involvement of microglia and complement in AD has been attributed to neuroinflammation, prominent late in disease. Here we show in mouse models that complement and microglia mediate synaptic loss early in AD. C1q, the initiating protein of the classical complement cascade, is increased and associated with synapses before overt plaque deposition. Inhibition of C1q, C3, or the microglial complement receptor CR3 reduces the number of phagocytic microglia, as well as the extent of early synapse loss. C1q is necessary for the toxic effects of soluble β-amyloid (Aβ) oligomers on synapses and hippocampal long-term potentiation. Finally, microglia in adult brains engulf synaptic material in a CR3-dependent process when exposed to soluble Aβ oligomers. Together, these findings suggest that the complement-dependent pathway and microglia that prune excess synapses in development are inappropriately activated and mediate synapse loss in AD.

  1. Minocycline attenuates Aβ oligomers-induced pro-inflammatory phenotype in primary microglia while enhancing Aβ fibrils phagocytosis.

    PubMed

    El-Shimy, Ismail Amr; Heikal, Ola Ahmed; Hamdi, Nabila

    2015-11-16

    Microglia, the brain innate immune cells, are activated in response to amyloid beta (Aβ) resulting in neuroinflammation in AD brains. Recently, two phenotypes have been described for microglia: the pro-inflammatory classical and the anti-inflammatory alternative. Changes in microglia phenotype that control their phagocytic function are yet to be determined. The highly neurotoxic Aβ oligomers (oAβ) formed at an early disease stage induce pro-inflammatory microglia activation releasing neurotoxic mediators and contributing to neurodegeneration. A novel strategy for AD treatment is to attenuate microglia-induced inflammation while maintaining efficient Aβ clearance. Minocycline effectively crosses the blood-brain barrier and has widely reported neuroprotective effects. Yet, its exact mechanism of neuroprotection and its effects on microglia are still unknown. The aim of this study is to investigate the effect of minocycline on the phagocytic uptake of fAβ by primary microglia in relation to their activation state in an inflammatory milieu generated by oAβ or LPS. The study shows that minocycline is able to attenuate oAβ-induced neuroinflammatory response of microglia by inhibiting their pro-inflammatory phenotype activation. In addition, a significant enhancement of fAβ phagocytosis by minocycline- treated microglia is reported for the first time, providing novel insight into its neuroprotective role in AD.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Expression of Nogo receptor 1 in microglia during development and following traumatic brain injury.

    PubMed

    Liu, Gaoxiang; Ni, Jie; Mao, Lei; Yan, Ming; Pang, Tao; Liao, Hong

    2015-11-19

    As the receptor of myelin associated inhibitory factors Nogo receptor 1 (NgR1) plays an important role in central nervous system (CNS) injury and regeneration. It is found that NgR1 complex acts in neurons to transduce the signals intracelluarly including induction of growth cone collapse, inhibition of axonal regeneration and regulation of nerve inflammation. In recent studies, NgR1 has also been found to be expressed in the microglia. However, NgR1 expressed in microglia in the developing nervous systems and following CNS injury have not been widely investigated. In this study, we detected the expression and cellular localization of NgR1 in microglia during development and following traumatic brain injury (TBI) in mice. The results showed that NgR1 was mainly expressed in microglia during embryonic and postnatal periods. The expression levels peaked at P4 and decreased thereafter into adulthood, while increased significantly with aging representatively at 17 mo. On the other hand, there was no significant difference in the number of double positive NgR1(+)Iba1(+) cells between normal and TBI group. In summary, we first detected the expression of NgR1 in microglia during development and found that NgR1 protein expression increased significantly in microglia with aging. These findings will contribute to make a foundation for subsequent study about the role of NgR1 expressed in microglia on the CNS disorders.

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

    PubMed

    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

  9. 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…

  10. A Taxonomy of Pretend Play Activity with Some Implications for Literacy Development.

    ERIC Educational Resources Information Center

    Roskos, K.

    A 6-month, qualitative study of the nature of literate behavior in the pretend play episodes of eight preschool children resulted in a taxonomy of their pretend play activity. Data were gathered in a setting where teachers implemented a cognitively oriented curriculum that encouraged language development and problem solving through play.…

  11. 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

  12. 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

  13. Selective estrogen receptor modulators regulate reactive microglia after penetrating brain injury

    PubMed Central

    Barreto, George E.; Santos-Galindo, Maria; Garcia-Segura, Luis Miguel

    2014-01-01

    Following brain injury, microglia assume a reactive-like state and secrete pro-inflammatory molecules that can potentiate damage. A therapeutic strategy that may limit microgliosis is of potential interest. In this context, selective estrogen receptor modulators, such as raloxifene and tamoxifen, are known to reduce microglia activation induced by neuroinflammatory stimuli in young animals. In the present study, we have assessed whether raloxifene and tamoxifen are able to affect microglia activation after brain injury in young and aged animals in time points relevant to clinics, which is hours after brain trauma. Volume fraction of MHC-II+ microglia was estimated according to the point-counting method of Weibel within a distance of 350 μm from the lateral border of the wound, and cellular morphology was measured by fractal analysis. Two groups of animals were studied: (1) young rats, ovariectomized at 2 months of age; and (2) aged rats, ovariectomized at 18 months of age. Fifteen days after ovariectomy animals received a stab wound brain injury and the treatment with estrogenic compounds. Our findings indicate that raloxifene and tamoxifen reduced microglia activation in both young and aged animals. Although the volume fraction of reactive microglia was found lower in aged animals, this was accompanied by important changes in cell morphology, where aged microglia assume a bushier and hyperplasic aspect when compared to young microglia. These data suggest that early regulation of microglia activation provides a mechanism by which selective estrogen receptors modulators (SERMs) may exert a neuroprotective effect in the setting of a brain trauma. PMID:24999330

  14. 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

  15. 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

  16. Mechanism of microglia neuroprotection: Involvement of P2X7, TNFα, and valproic acid.

    PubMed

    Masuch, Annette; Shieh, Chu-Hsin; van Rooijen, Nico; van Calker, Dietrich; Biber, Knut

    2016-01-01

    Recently, we have demonstrated that ramified microglia are neuroprotective in N-methyl-D-aspartate (NMDA)-induced excitotoxicity in organotypic hippocampal slice cultures (OHSCs). The present study aimed to elucidate the underlying neuron-glia communication mechanism. It is shown here that pretreatment of OHSC with high concentrations of adenosine 5'-triphosphate (ATP) reduced NMDA-induced neuronal death only in presence of microglia. Specific agonists and antagonists identified the P2X7 receptor as neuroprotective receptor which was confirmed by absence of ATP-dependent neuroprotection in P2X7-deficient OHSC. Microglia replenished chimeric OHSC consisting of wild-type tissue replenished with P2X7-deficient microglia confirmed the involvement of microglial P2X7 receptor in neuroprotection. Stimulation of P2X7 in primary microglia induced tumor necrosis factor α (TNFα) release and blocking TNFα by a neutralizing antibody in OHSC abolished neuroprotection by ATP. OHSC from TNFα-deficient mice show increased exicitoxicity and activation of P2X7 did not rescue neuronal survival in the absence of TNFα. The neuroprotective effect of valproic acid (VPA) was strictly dependent on the presence of microglia and was mediated by upregulation of P2X7 in the cells. The present study demonstrates that microglia-mediated neuroprotection depends on ATP-activated purine receptor P2X7 and induction of TNFα release. This neuroprotective pathway was strengthened by VPA elucidating a novel mechanism for the neuroprotective function of VPA.

  17. 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…

  18. 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…

  19. 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.…

  20. Microglia overexpressing the macrophage colony-stimulating factor receptor are neuroprotective in a microglial-hippocampal organotypic coculture system.

    PubMed

    Mitrasinovic, Olivera M; Grattan, Alicia; Robinson, Christopher C; Lapustea, Nicolae B; Poon, Clara; Ryan, Heather; Phong, Connie; Murphy, Greer M

    2005-04-27

    Microglia with increased expression of the macrophage colony-stimulating factor receptor (M-CSFR; c-fms) are found surrounding plaques in Alzheimer's disease (AD) and in mouse models for AD and after ischemic or traumatic brain injury. Increased expression of M-CSFR causes microglia to adopt an activated state that results in proliferation, release of cytokines, and enhanced phagocytosis. To determine whether M-CSFR-induced microglial activation affects neuronal survival, we assembled a coculture system consisting of BV-2 microglia transfected to overexpress the M-CSFR and hippocampal organotypic slices treated with NMDA. Twenty-four hours after assembly of the coculture, microglia overexpressing M-CSFR proliferated at a higher rate than nontransfected control cells and exhibited enhanced migration toward NMDA-injured hippocampal cultures. Surprisingly, coculture with c-fms-transfected microglia resulted in a dramatic reduction in NMDA-induced neurotoxicity. Similar results were observed when cocultures were treated with the teratogen cyclophosphamide. Biolistic overexpression of M-CSFR on microglia endogenous to the organotypic culture also rescued neurons from excitotoxicity. Furthermore, c-fms-transfected microglia increased neuronal expression of macrophage colony-stimulating factor (M-CSF), the M-CSFR, and neurotrophin receptors in the NMDA-treated slices, as determined with laser capture microdissection. In the coculture system, direct contact between the exogenous microglia and the slice was necessary for neuroprotection. Finally, blocking expression of the M-CSF ligand by exogenous c-fms-transfected microglia with a hammerhead ribozyme compromised their neuroprotective properties. These results demonstrate a protective role for microglia overexpressing M-CSFR in our coculture system and suggest under certain circumstances, activated microglia can help rather than harm neurons subjected to excitotoxic and teratogen-induced injury.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Cellular activation in limbic brain systems during social play behaviour in rats.

    PubMed

    van Kerkhof, Linda W M; Trezza, Viviana; Mulder, Tessa; Gao, Ping; Voorn, Pieter; Vanderschuren, Louk J M J

    2014-07-01

    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 organized 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 organized neural network implicated in processes such as reward, motivation and cognitive control over behaviour, which mediates social play behaviour in rats. PMID:23670540

  10. Cellular activation in limbic brain systems during social play behaviour in rats.

    PubMed

    van Kerkhof, Linda W M; Trezza, Viviana; Mulder, Tessa; Gao, Ping; Voorn, Pieter; Vanderschuren, Louk J M J

    2014-07-01

    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 organized 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 organized neural network implicated in processes such as reward, motivation and cognitive control over behaviour, which mediates social play behaviour in rats.

  11. SnapShot: Microglia in Disease.

    PubMed

    Beggs, Simon; Salter, Michael W

    2016-05-19

    The development and maintenance of the central nervous system is dependent upon regulated, homeostatic actions of microglia, which sculpt and refine neuronal circuitry. By contrast, dysregulation of microglia contributes to the pathology of neurodevelopmental disorders such as autism spectrum disorders; neurodegenerative disorders such as Alzheimer's disease; and schizophrenia and chronic neuropathic pain.

  12. Increasing Play Skills of Children with Autism Using Activity Schedules and Correspondence Training.

    ERIC Educational Resources Information Center

    Morrison, Rebecca S.; Sainato, Diane M.; BenChaaban, Delia; Endo, Sayaka

    2002-01-01

    A study investigated the effectiveness of correspondence training and photographic activity schedules on the on-task and play correspondence behavior of four preschool children with autism in an inclusive setting. Results indicate that all participants' on-task and play correspondence behavior increased, while experimenter prompts gradually…

  13. A Spatio-Pedagogical Approach to Symbolic Play as Kindergarten Activity in Early Childhood.

    ERIC Educational Resources Information Center

    Michalopoulou, Aikaterini

    2001-01-01

    Studied the symbolic play that occurs in activity corners set up around toy-objects in Greek kindergartens. Found notable differences in levels of symbolism and complexity of the play. Concluded that the most favored groups were those in which: (1) classroom space was polyvalent, permitting its informal re-organization; and (2) the teacher was an…

  14. 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…

  15. USP18 lack in microglia causes destructive interferonopathy of the mouse brain

    PubMed Central

    Goldmann, Tobias; Zeller, Nicolas; Raasch, Jenni; Kierdorf, Katrin; Frenzel, Kathrin; Ketscher, Lars; Basters, Anja; Staszewski, Ori; Brendecke, Stefanie M; Spiess, Alena; Tay, Tuan Leng; Kreutz, Clemens; Timmer, Jens; Mancini, Grazia MS; Blank, Thomas; Fritz, Günter; Biber, Knut; Lang, Roland; Malo, Danielle; Merkler, Doron; Heikenwälder, Mathias; Knobeloch, Klaus-Peter; Prinz, Marco

    2015-01-01

    Microglia are tissue macrophages of the central nervous system (CNS) that control tissue homeostasis. Microglia dysregulation is thought to be causal for a group of neuropsychiatric, neurodegenerative and neuroinflammatory diseases, called “microgliopathies”. However, how the intracellular stimulation machinery in microglia is controlled is poorly understood. Here, we identified the ubiquitin-specific protease (Usp) 18 in white matter microglia that essentially contributes to microglial quiescence. We further found that microglial Usp18 negatively regulates the activation of Stat1 and concomitant induction of interferon-induced genes, thereby terminating IFN signaling. The Usp18-mediated control was independent from its catalytic activity but instead required the interaction with Ifnar2. Additionally, the absence of Ifnar1 restored microglial activation, indicating a tonic IFN signal which needs to be negatively controlled by Usp18 under non-diseased conditions. These results identify Usp18 as a critical negative regulator of microglia activation and demonstrate a protective role of Usp18 for microglia function by regulating the Ifnar pathway. The findings establish Usp18 as a new molecule preventing destructive microgliopathy. PMID:25896511

  16. Language through the Seasons: Dramatic Play Activities for Early Childhood Learners.

    ERIC Educational Resources Information Center

    Amdur, Judith

    This workbook brings together activities to aid in motivating children to concentrate, listen, respond, think, and learn. The activities rely upon play-like tasks involving drama, music, and other forms of creative expression. The activities are organized by the season in which they are appropriate and include songs, dramatic sequences, stories,…

  17. 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…

  18. 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

  19. Impairment of in vivo calcium signaling in amyloid plaque-associated microglia.

    PubMed

    Brawek, Bianca; Schwendele, Bernd; Riester, Karin; Kohsaka, Shinichi; Lerdkrai, Chommanad; Liang, Yajie; Garaschuk, Olga

    2014-04-01

    Neuroinflammation is a hallmark of Alzheimer's disease (AD) both in man and in multiple mouse models, and epidemiological studies link the use of anti-inflammatory drugs with a reduced risk of developing the disease. AD-related neuroinflammation is largely mediated by microglia, the main immune cells of the central nervous system. In vitro, executive functions of microglia are regulated by intracellular Ca(2+) signals, but little is known about microglial Ca(2+) signaling in vivo. Here we analyze in vivo properties of these cells in two mouse models of AD. In both strains plaque-associated microglia had hypertrophic/amoeboid morphology and were strongly positive for markers of activation such as CD11b and CD68. Activated microglia failed to respond reliably to extracellular release of adenosine triphosphate (ATP, mimicking tissue damage) and showed an increased incidence of spontaneous intracellular Ca(2+) transients. These Ca(2+) transients required activation of ATP receptors and Ca(2+) release from the intracellular Ca(2+) stores, and were not induced by neuronal or astrocytic hyperactivity. Neuronal silencing, however, selectively increased the frequency of Ca(2+) transients in plaque-associated microglia. Thus, our in vivo data reveal substantial dysfunction of plaque-associated microglia and identify a novel Ca(2+) signal possibly triggering a Ca(2+)-dependent release of toxic species in the plaque vicinity.

  20. Development of various reaction abilities and their relationships with favorite play activities in preschool children.

    PubMed

    Miyaguchi, Kazuyoshi; Demura, Shinich; Sugiura, Hiroki; Uchiyama, Masanobu; Noda, Masahiro

    2013-10-01

    This study examines the development of various reaction movements in preschool children and the relationship between reaction times and favorite play activities. The subjects were 167 healthy preschool children aged 4-6 (96 boys and 71 girls). This study focused on the reaction times of the upper limbs (reaction 1: release; reaction 2: press) and the whole body (reaction 3: forward jump). The activities frequently played in preschools are largely divided into dynamic play activities (tag, soccer, gymnastics set, dodge ball, and jump rope) and static play activities (drawing, playing house, reading, playing with sand, and building blocks). The subjects chose 3 of 10 cards picturing their favorite play activities, depicting 10 different activities. All intraclass correlation coefficients of measured reaction times were high (0.73-0.79). In addition, each reaction time shortened with age. Reaction 1 showed a significant and low correlation with reaction 3 (r = 0.37). The effect size of the whole body reaction time was the largest. Whole body reaction movement, which is largely affected by the exercise output function, develops remarkably in childhood. Children who liked "tag" were faster in all reaction times. The children who chose "soccer" were faster in reactions 2 and 3. In contrast, children who liked "playing house" tended to have slower reaction times. Dynamic activities, such as tag and soccer, promote development of reaction speed and agility in movements involving the whole body. Preschool teachers and physical educators should re-examine the effect of tag and use it periodically as one of the exercise programs to avoid unexpected falls and injuries in everyday life. PMID:23302758

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. Radixin expression in microglia after cortical stroke lesion.

    PubMed

    Persson, Åsa; Osman, Ahmed; Bolouri, Hayde; Mallard, Carina; Kuhn, H Georg

    2013-05-01

    Stroke induces extensive tissue remodeling, resulting in the activation of several cell types in the brain as well as recruitment of blood-borne leucocytes. Radixin is part of a cytoskeleton linker protein family with the ability to connect transmembrane proteins to the actin cytoskeleton, promoting cell functions involving a dynamic cytoskeleton such as morphological changes, cell division and migration which are common events of different cell types after stroke. In the healthy adult brain radixin is expressed in Olig2(+) cells throughout the brain and in neural progenitor cells in the subventricular zone. In the current study, we detected a 2.5 fold increase in the number of radixin positive cells in the peri-infarct cortex two weeks after the induction of cortical stroke by photothrombosis. Similarly, the number of Olig2(+) cells increased in the peri-infarct area after stroke; however, the number of radixin(+)/Olig2(+) cells was unchanged. Neural progenitor cells maintained radixin expression on their route to the infarct. More surprising however, was the expression of radixin in activated microglia in the peri-infarct cortex. Seventy percent of Iba1(+) cells expressed radixin after stroke, a population which was not present in the control brain. Furthermore, activation of radixin was predominantly detected in the peri-infarct region of oligodendrocyte progenitors and microglia. The specific location of radixin(+) cells in the peri-infarct region and in microglia suggests a role for radixin in microglial activation after stroke.

  8. HIV-1 gp120 enhances outward potassium current via CXCR4 and cAMP-dependent PKA signaling in cultured rat microglia

    PubMed Central

    Xu, Changshui; Liu, Jianuo; Chen, Lina; Liang, Shangdong; Fujii, Nobutaka; Tamamura, Hirokazu; Xiong, Huangui

    2011-01-01

    Microglia are critical cells in mediating the pathophysiology of neurodegenerative disorders such as HIV-associated neurocognitive disorders. We hypothesize that HIV-1 glycoprotein 120 (gp120) activates microglia by enhancing outward K+ currents, resulting in microglia secretion of neurotoxins and consequent neuronal dysfunction and death. To test this hypothesis, we studied the effects of gp120 on outward K+ current in cultured rat microglia. Application of gp120 enhanced outward K+ current in a dose-dependent manner, which was blocked by voltage-gated K+ (Kv) channel blockers. Western blot analysis revealed that gp120 produced an elevated expression of Kv channel proteins. Examination of activation and inactivation of outward K+ currents showed that gp120 shifted membrane potentials for activation and steady-state inactivation. The gp120-associated enhancement of outward K+ current was blocked by a CXCR4 receptor antagonist T140 or by a specific protein kinase A (PKA) inhibitor H89, suggesting the involvement of chemokine receptor CXCR4 and PKA in gp120-mediated enhancement of outward K+ current. Biological significance of gp120-induced enhancement of microglia outward K+ current was demonstrated by experimental results showing the neurotoxic activity of gp120-stimulated microglia, evaluated by TUNEL staining and MTT assay, was significantly attenuated by Kv channel blockers. Taken together, these results suggest that gp120 induces microglia neurotoxic activity by enhancing microglia outward K+ current and that microglia Kv channels may function as a potential target for the development of therapeutic strategies. PMID:21438014

  9. 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

  10. 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.

  11. The role of microglia in brain maintenance: implications for Rett syndrome.

    PubMed

    Derecki, Noël C; Cronk, James C; Kipnis, Jonathan

    2013-03-01

    The role of microglia in central nervous system (CNS) pathology has been studied extensively, and more recently, examination of microglia in the healthy brain has yielded important insights into their many functions. It was long assumed that microglia were essentially quiescent cells, unless provoked into activation, which was considered a hallmark of disease. More recently, however, it has become increasingly clear that they are extraordinarily dynamic cells, constantly sampling their environment and adjusting to exquisitely delicate stimuli. Along these lines, our laboratory has identified a new and unexpected role for microglial phagocytosis - or lack thereof - in the pathophysiology of Rett syndrome, a neurodevelopmental disease caused by mutation of the gene encoding methyl-CpG binding protein (MECP)2. We have shown that specific expression of wild type Mecp2 in myeloid cells of Mecp2-null mice is sufficient to arrest major symptoms associated with this devastating disease. This beneficial effect, however, is abolished if phagocytic activity of microglia is inhibited. Here, we discuss microglial origins, the role of microglia in brain development and maintenance, and the phenomenon of microglial augmentation by myeloid progenitor cells in the adult brain. Finally, we address in some detail the beneficial roles of microglia as clinical targets in Rett syndrome and other neurological disorders.

  12. Changes in cue-induced, prefrontal cortex activity with video-game play.

    PubMed

    Han, Doug Hyun; Kim, Yang Soo; Lee, Yong Sik; Min, Kyung Joon; Renshaw, Perry F

    2010-12-01

    Brain responses, particularly within the orbitofrontal and cingulate cortices, to Internet video-game cues in college students are similar to those observed in patients with substance dependence in response to the substance-related cues. In this study, we report changes in brain activity between baseline and following 6 weeks of Internet video-game play. We hypothesized that subjects with high levels of self-reported craving for Internet video-game play would be associated with increased activity in the prefrontal cortex, particularly the orbitofrontal and anterior cingulate cortex. Twenty-one healthy university students were recruited. At baseline and after a 6-week period of Internet video-game play, brain activity during presentation of video-game cues was assessed using 3T blood oxygen level dependent functional magnetic resonance imaging. Craving for Internet video-game play was assessed by self-report on a 7-point visual analogue scale following cue presentation. During a standardized 6-week video-game play period, brain activity in the anterior cingulate and orbitofrontal cortex of the excessive Internet game-playing group (EIGP) increased in response to Internet video-game cues. In contrast, activity observed in the general player group (GP) was not changed or decreased. In addition, the change of craving for Internet video games was positively correlated with the change in activity of the anterior cingulate in all subjects. These changes in frontal-lobe activity with extended video-game play may be similar to those observed during the early stages of addiction.

  13. 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

  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

    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.

  15. A high resolution EEG study of dynamic brain activity during video game play.

    PubMed

    Sheikholeslami, C; Yuan, H; He, E J; Bai, X; Yang, L; He, B

    2007-01-01

    A high resolution EEG study was conducted on healthy human subjects during video game play. Throughout the game playing experiment short time segments of spontaneous activity were recorded. Spectral analysis was performed on these segments for the theta-wave (4-8 Hz) and alpha-wave (8-13 Hz) bands to investigate the modulatory effects of long-lasting game play and the dynamic changes of spectral contribution in range of alpha-and theta-wave. The present results revealed that a) the frontal midline theta-wave activity increased over time relative to the eye open resting condition and b) the parietal alpha-wave activity initially decreased relative to the resting condition, then followed by a slow increase. These experimental results indicate the high resolution EEG provides a useful quantitative analysis tool for studying dynamic brain activity.

  16. 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…

  17. Recipes for Fun: Play Activities and Games for Young Children with Disabilities and Their Families.

    ERIC Educational Resources Information Center

    Rappaport, Lisa

    Intended for friends and families of children with disabilities, the book contains information and suggestions on play activities, toys, and games for children (0-8) with mild and moderate disabilities. Activities are sequenced from simpler to more developmentally advanced within six major categories (1) exploring the senses (hid and find,…

  18. 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…

  19. 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…

  20. 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…

  1. 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...

  2. 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…

  3. Read, Play, and Learn! Storybook Activities for Young Children. The Transdisciplinary Play-Based