Involvement of the PI3K/Akt/GSK3β pathway in photodynamic injury of neurons and glial cells

NASA Astrophysics Data System (ADS)

Komandirov, M. A.; Knyazeva, E. A.; Fedorenko, Y. P.; Rudkovskii, M. V.; Stetsurin, D. A.; Uzdensky, A. B.

2011-03-01

Photodynamic treatment causes intense oxidative stress and kills cells. It is currently used in neurooncology. However, along with tumor it damages surrounding healthy neuronal and glial cells. In order to study the possible role of the phosphatidylinositol 3-kinase/protein kinase Akt/glycogen synthase kinase-3β signaling pathway in photodynamic damage to normal neurons and glia, we used isolated crayfish stretch receptor that consists only of a single neuron surrounded by glial cells. It was photosensitized with alumophthalocyanine Photosens (100 nM). The laser diode (670nm, 0.4W/cm2) was used as a light source. Application of specific inhibitors of the enzymes involved in this pathway showed that phosphatidylinositol 3-kinase did not participate in photoinduced death of neurons and glia. Protein kinase Akt was involved in photoinduced necrosis but not in apoptosis of neurons and glia. Glycogen synthase kinase-3β participated in photoinduced apoptosis of glial cells and in necrosis of neurons. Therefore, the phosphatidylinositol 3-kinase/protein kinase Akt/glycogen synthase kinase-3β pathway was not involved as a whole in photodynamic injury of crayfish neurons and glial cells but its components, protein kinase Akt and glycogen synthase kinase-3β, independently and cell-specifically regulated photoinduced death of neurons and glial cells. These data showed that in this system necrosis was not non-regulated and catastrophic mode of cell death. It was controlled by some signaling proteins. The obtained results may be used for search of pharmacological agents that selectively modulate injury of normal neurons and glial cells during photodynamic therapy of brain tumors.

On the role of phosphatidylinositol 3-kinase, protein kinase b/Akt, and glycogen synthase kinase-3β in photodynamic injury of crayfish neurons and glial cells.

PubMed

Komandirov, Maxim A; Knyazeva, Evgeniya A; Fedorenko, Yulia P; Rudkovskii, Mikhail V; Stetsurin, Denis A; Uzdensky, Anatoly B

2011-10-01

Photodynamic treatment that causes intense oxidative stress and cell death is currently used in neurooncology. However, along with tumor cells, it may damage healthy neurons and glia. To study the involvement of signaling processes in photodynamic injury or protection of neurons and glia, we used crayfish mechanoreceptor consisting of a single neuron surrounded by glial cells. It was photosensitized with alumophthalocyanine Photosens. Application of specific inhibitors showed that phosphatidylinositol 3-kinase did not participate in photoinduced death of neurons and glia. Akt was involved in photoinduced necrosis but not in apoptosis of neurons and glia. Glycogen synthase kinase-3β participated in photoinduced apoptosis of glial cells and in necrosis of neurons. Therefore, phosphatidylinositol 3-kinase/protein kinase Akt/glycogen synthase kinase-3β pathway was not involved as a whole in photodynamic injury of crayfish neurons and glia but its components, Akt and glycogen synthase kinase-3β, independently and cell specifically regulated death of neurons and glial cells. According to these data, necrosis in this system was a controlled but not a non-regulated cell death mode. The obtained results may be used for the search of pharmacological agents selectively modulating death and survival of normal neurons and glial cells during photodynamic therapy of brain tumors.

Molecular mechanism of central nervous system repair by the Drosophila NG2 homologue kon-tiki

PubMed Central

Harrison, Neale

2016-01-01

Neuron glia antigen 2 (NG2)–positive glia are repair cells that proliferate upon central nervous system (CNS) damage, promoting functional recovery. However, repair is limited because of the failure of the newly produced glial cells to differentiate. It is a key goal to discover how to regulate NG2 to enable glial proliferation and differentiation conducive to repair. Drosophila has an NG2 homologue called kon-tiki (kon), of unknown CNS function. We show that kon promotes repair and identify the underlying mechanism. Crush injury up-regulates kon expression downstream of Notch. Kon in turn induces glial proliferation and initiates glial differentiation by activating glial genes and prospero (pros). Two negative feedback loops with Notch and Pros allow Kon to drive the homeostatic regulation required for repair. By modulating Kon levels in glia, we could prevent or promote CNS repair. Thus, the functional links between Kon, Notch, and Pros are essential for, and can drive, repair. Analogous mechanisms could promote CNS repair in mammals. PMID:27551055

Calcium signal communication in the central nervous system.

PubMed

Braet, Katleen; Cabooter, Liesbet; Paemeleire, Koen; Leybaert, Luc

2004-02-01

The communication of calcium signals between cells is known to be operative between neurons where these signals integrate intimately with electrical and chemical signal communication at synapses. Recently, it has become clear that glial cells also exchange calcium signals between each other in cultures and in brain slices. This communication pathway has received utmost attention since it is known that astrocytic calcium signals can be induced by neuronal stimulation and can be communicated back to the neurons to modulate synaptic transmission. In addition to this, cells that are generally not considered as brain cells become progressively incorporated in the picture, as astrocytic calcium signals are reported to be communicated to endothelial cells of the vessel wall and can affect smooth muscle cell tone to influence the vessel diameter and thus blood flow. We review the available evidence for calcium signal communication in the central nervous system, taking into account a basic functional unit -the brain cell tripartite- consisting of neurons, glial cells and vascular cells and with emphasis on glial-vascular calcium signaling aspects.

GABA as a rising gliotransmitter

PubMed Central

Yoon, Bo-Eun; Lee, C. Justin

2014-01-01

Gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter that is known to be synthesized and released from GABAergic neurons in the brain. However, recent studies have shown that not only neurons but also astrocytes contain a considerable amount of GABA that can be released and activate GABA receptors in neighboring neurons. These exciting new findings for glial GABA raise further interesting questions about the source of GABA, its mechanism of release and regulation and the functional role of glial GABA. In this review, we highlight recent studies that identify the presence and release of GABA in glial cells, we show several proposed potential pathways for accumulation and modulation of glial intracellular and extracellular GABA content, and finally we discuss functional roles for glial GABA in the brain. PMID:25565970

Glial diffusion barriers during aging and pathological states.

PubMed

Syková, E

2001-01-01

In conclusion, glial cells control not only ECS ionic composition, but also ECS size and geometry. Since ECS ionic and volume changes have been shown to play an important role in modulating the complex synaptic and extrasynaptic signal transmission in the CNS, glial cells may thus affect neuronal interaction, synchronization and neuron-glia communication. As shown in Fig. 2, a link between ionic and volume changes and signal transmission has been proposed as a model for the non-specific feedback mechanism suppressing neuronal activity (Syková, 1997; Ransom, 2000). First, neuronal activity results in the accumulation of [K+]e, which in turn depolarizes glial cells, and this depolarization induces an alkaline shift in glial pHi. Second, the glial cells extrude acid and the resulting acid shift causes a decrease in the neuronal excitability. Because ionic transmembrane shifts are always accompanied by water, this feedback mechanism is amplified by activity-related glial swelling compensated for by ECS volume shrinkage and by increased tortuosity, presumably by the crowding of molecules of the ECS matrix and/or by the swelling of fine glial processes. This, in turn, results in a larger accumulation of ions and other neuroactive substances in the brain due to increased diffusion hinderance in the ECS. Astrocyte hypertrophy, proliferation and swelling influence the size of the ECS volume and tortuosity around neurons, slowing diffusion in the ECS. Their organization may also affect diffusion anisotropy, which could be an underlying mechanism for the specificity of extrasynaptic transmission, including 'cross-talk' between distinct synapses (Barbour and Hausser, 1997; Kullmann and Asztely, 1998). An increased concentration of transmitter released into a synapse (e.g. repetitive adequate stimuli or during high frequency electrical stimulation which induces LTP) results in a significant activation of high-affinity receptors at neighboring synapses. The efficacy of such synaptic cross-talk would be dependent on the extracellular space surrounding the synapses, i.e. on intersynaptic geometry and diffusion parameters. Other recent studies have also suggested an important role for proteoglycans, known to participate in multiple cellular processes, such as axonal outgrowth, axonal branching and synaptogenesis (Hardington and Fosang, 1992; Margolis and Margolis, 1993) that are important for the formation of memory traces. Recent observation of a decrease of fibronectin and chondroitin sulfate proteoglycan staining in the hippocampus of behaviorally impaired aged rats (Syková et al., 1998a,b) supports this hypothesis. It is reasonable to assume that besides neuronal and glial processes, macromolecules of the extracellular matrix contribute to diffusion barriers in the ECS. It is therefore apparent that glial cells play an important role in the local architecture of the CNS and they may also be involved in the modulation of signal transmission, in plastic changes, LTP, LTD and in changes of behavior and memory formation.

Targeting Glia with N-Acetylcysteine Modulates Brain Glutamate and Behaviors Relevant to Neurodevelopmental Disorders in C57BL/6J Mice

PubMed Central

Durieux, Alice M. S.; Fernandes, Cathy; Murphy, Declan; Labouesse, Marie Anais; Giovanoli, Sandra; Meyer, Urs; Li, Qi; So, Po-Wah; McAlonan, Grainne

2015-01-01

An imbalance between excitatory (E) glutamate and inhibitory (I) GABA transmission may underlie neurodevelopmental conditions such as autism spectrum disorder (ASD) and schizophrenia. This may be direct, through alterations in synaptic genes, but there is increasing evidence for the importance of indirect modulation of E/I balance through glial mechanisms. Here, we used C57BL/6J mice to test the hypothesis that striatal glutamate levels can be shifted by N-acetylcysteine (NAC), which acts at the cystine-glutamate antiporter of glial cells. Striatal glutamate was quantified in vivo using proton magnetic resonance spectroscopy. The effect of NAC on behaviors relevant to ASD was examined in a separate cohort. NAC induced a time-dependent decrease in striatal glutamate, which recapitulated findings of lower striatal glutamate reported in ASD. NAC-treated animals were significantly less active and more anxious in the open field test; and NAC-treated females had significantly impaired prepulse inhibition of startle response. This at least partly mimics greater anxiety and impaired sensorimotor gating reported in neurodevelopmental disorders. Thus glial mechanisms regulate glutamate acutely and have functional consequences even in adulthood. Glial cells may be a potential drug target for the development of new therapies for neurodevelopmental disorders across the life-span. PMID:26696857

The role of NO synthase isoforms in PDT-induced injury of neurons and glial cells

NASA Astrophysics Data System (ADS)

Kovaleva, V. D.; Berezhnaya, E. V.; Uzdensky, A. B.

2015-03-01

Nitric oxide (NO) is an important second messenger, involved in the implementation of various cell functions. It regulates various physiological and pathological processes such as neurotransmission, cell responses to stress, and neurodegeneration. NO synthase is a family of enzymes that synthesize NO from L-arginine. The activity of different NOS isoforms depends both on endogenous and exogenous factors. In particular, it is modulated by oxidative stress, induced by photodynamic therapy (PDT). We have studied the possible role of NOS in the regulation of survival and death of neurons and surrounding glial cells under photo-oxidative stress induced by photodynamic treatment (PDT). The crayfish stretch receptor consisting of a single identified sensory neuron enveloped by glial cells is a simple but informative model object. It was photosensitized with alumophthalocyanine photosens (10 nM) and irradiated with a laser diode (670 nm, 0.4 W/cm2). Antinecrotic and proapoptotic effects of NO on the glial cells were found using inhibitory analysis. We have shown the role of inducible NO synthase in photoinduced apoptosis and involvement of neuronal NO synthase in photoinduced necrosis of glial cells in the isolated crayfish stretch receptor. The activation of NO synthase was evaluated using NADPH-diaphorase histochemistry, a marker of neurons expressing the enzyme. The activation of NO synthase in the isolated crayfish stretch receptor was evaluated as a function of time after PDT. Photodynamic treatment induced transient increase in NO synthase activity and then slowly inhibited this enzyme.

Molecular mechanism of central nervous system repair by the Drosophila NG2 homologue kon-tiki.

PubMed

Losada-Perez, Maria; Harrison, Neale; Hidalgo, Alicia

2016-08-29

Neuron glia antigen 2 (NG2)-positive glia are repair cells that proliferate upon central nervous system (CNS) damage, promoting functional recovery. However, repair is limited because of the failure of the newly produced glial cells to differentiate. It is a key goal to discover how to regulate NG2 to enable glial proliferation and differentiation conducive to repair. Drosophila has an NG2 homologue called kon-tiki (kon), of unknown CNS function. We show that kon promotes repair and identify the underlying mechanism. Crush injury up-regulates kon expression downstream of Notch. Kon in turn induces glial proliferation and initiates glial differentiation by activating glial genes and prospero (pros). Two negative feedback loops with Notch and Pros allow Kon to drive the homeostatic regulation required for repair. By modulating Kon levels in glia, we could prevent or promote CNS repair. Thus, the functional links between Kon, Notch, and Pros are essential for, and can drive, repair. Analogous mechanisms could promote CNS repair in mammals. © 2016 Losada-Perez et al.

Neuropeptides and Microglial Activation in Inflammation, Pain, and Neurodegenerative Diseases

PubMed Central

2017-01-01

Microglial cells are responsible for immune surveillance within the CNS. They respond to noxious stimuli by releasing inflammatory mediators and mounting an effective inflammatory response. This is followed by release of anti-inflammatory mediators and resolution of the inflammatory response. Alterations to this delicate process may lead to tissue damage, neuroinflammation, and neurodegeneration. Chronic pain, such as inflammatory or neuropathic pain, is accompanied by neuroimmune activation, and the role of glial cells in the initiation and maintenance of chronic pain has been the subject of increasing research over the last two decades. Neuropeptides are small amino acidic molecules with the ability to regulate neuronal activity and thereby affect various functions such as thermoregulation, reproductive behavior, food and water intake, and circadian rhythms. Neuropeptides can also affect inflammatory responses and pain sensitivity by modulating the activity of glial cells. The last decade has witnessed growing interest in the study of microglial activation and its modulation by neuropeptides in the hope of developing new therapeutics for treating neurodegenerative diseases and chronic pain. This review summarizes the current literature on the way in which several neuropeptides modulate microglial activity and response to tissue damage and how this modulation may affect pain sensitivity. PMID:28154473

Bergmann glia modulate cerebellar Purkinje cell bistability via Ca2+-dependent K+ uptake

PubMed Central

Wang, Fushun; Xu, Qiwu; Wang, Weishan; Takano, Takahiro; Nedergaard, Maiken

2012-01-01

Recent studies have shown that cerebellar Bergmann glia display coordinated Ca2+ transients in live mice. However, the functional significance of Bergmann glial Ca2+ signaling remains poorly understood. Using transgenic mice that allow selective stimulation of glial cells, we report here that cytosolic Ca2+ regulates uptake of K+ by Bergmann glia, thus providing a powerful mechanism for control of Purkinje cell-membrane potential. The decline in extracellular K+ evoked by agonist-induced Ca2+ in Bergmann glia transiently increased spike activity of Purkinje cells in cerebellar slices as well as in live anesthetized mice. Thus, Bergmann glia play a previously unappreciated role in controlling the membrane potential and thereby the activity of adjacent Purkinje cells. PMID:22547829

Effects of memantine on soluble Alphabeta(25-35)-induced changes in peptidergic and glial cells in Alzheimer's disease model rat brain regions.

PubMed

Arif, M; Chikuma, T; Ahmed, Md M; Nakazato, M; Smith, M A; Kato, T

2009-12-15

Soluble forms of amyloid-beta (Abeta) have been considered responsible for cognitive dysfunction prior to senile plaque formation in Alzheimer's disease (AD). As its mechanism is not well understood, we examined the effects of repeated i.c.v. infusion of soluble Alphabeta(25-35) on peptidergic system and glial cells in the pathogenesis of AD. The present study aims to investigate the protective effects of memantine on Abeta(25-35)-induced changes in peptidergic and glial systems. Infusion of Alphabeta(25-35) decreased the level of immunoreactive somatostatin (SS) and substance P (SP) in the hippocampus prior to neuronal loss or caspase activation, which is correlated with the loss of spine density and activation of inducible nitric-oxide synthase (iNOS). Biochemical experiment with peptide-degrading enzymes, prolyl oligopeptidase (POP) and endopeptidase 24.15 (EP 24.15) activities demonstrated a concomitant increase with the activation of glial marker proteins, glial fibrillary acidic protein (GFAP) and CD11b in the Abeta-treated hippocampus. Double immunostaining experiments of EP 24.15 and GFAP/CD11b antibodies clearly demonstrated the co-localization of neuro peptidases with astrocytes and microglia. Treatment with memantine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist significantly attenuated Abeta(25-35)-induced changes of neuropeptides, their metabolizing enzymes, glial marker proteins, and activation of iNOS. Taken together, the data implies that memantine exerts its protective effects by modulating the neuropeptide system as a consequence of suppressing the glial cells and oxidative stress in AD model rat brain regions.

Glial cell migration in the eye disc.

PubMed

Silies, Marion; Yuva, Yeliz; Engelen, Daniel; Aho, Annukka; Stork, Tobias; Klämbt, Christian

2007-11-28

Any complex nervous system is made out of two major cell types, neurons and glial cells. A hallmark of glial cells is their pronounced ability to migrate. En route to their final destinations, glial cells are generally guided by neuronal signals. Here we show that in the developing visual system of Drosophila glial cell migration is largely controlled by glial-glial interactions and occurs independently of axonal contact. Differentiation into wrapping glia is initiated close to the morphogenetic furrow. Using single cell labeling experiments we identified six distinct glial cell types in the eye disc. The migratory glial population is separated from the wrapping glial cells by the so-called carpet cells, extraordinary large glial cells, each covering a surface area of approximately 10,000 epithelial cells. Subsequent cell ablation experiments demonstrate that the carpet glia regulates glial migration in the eye disc epithelium and suggest a new model underlying glial migration and differentiation in the developing visual system.

Diverse Physiological Roles of Calcitonin Gene-Related Peptide in Migraine Pathology: Modulation of Neuronal-Glial-Immune Cells to Promote Peripheral and Central Sensitization

PubMed Central

Durham, Paul L.

2018-01-01

The neuropeptide calcitonin gene-related peptide (CGRP) is implicated in the underlying pathology of migraine by promoting the development of a sensitized state of primary and secondary nociceptive neurons. The ability of CGRP to initiate and maintain peripheral and central sensitization is mediated by modulation of neuronal, glial, and immune cells in the trigeminal nociceptive signaling pathway. There is accumulating evidence to support a key role of CGRP in promoting cross excitation within the trigeminal ganglion that may help to explain the high co-morbidity of migraine with rhinosinusitis and temporomandibular joint disorder. In addition, there is emerging evidence that CGRP facilitates and sustains a hyperresponsive neuronal state in migraineurs mediated by reported risk factors such as stress and anxiety. In this review, the significant role of CGRP as a modulator of the trigeminal system will be discussed to provide a better understanding of the underlying pathology associated with the migraine phenotype. PMID:27334137

Glial-released proteins in clonal cultures and their modulation by hydrocortisone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arenander, A.T.; de Vellis, J.

Rat glial C6 cells release into the culture medium a reproducible spectrum of soluble proteins of 12 major peaks over a broad molecular weight range as determined by fractionation on SDS-gel electrophoresis. Exposing C6 monolayers to hydrocortisone (HC) results in a selective alteration in the pattern of glial-released protein (GRP). The selective HC-induced increase or decrease in GRP peaks is specific to HC in that 17 ..beta..-estradiol, dibutyryl cyclic AMP, isoproterenol, and melatonin exert either no detectable or a qualitatively different influence on the GRP pattern. The HC influence is dose dependent over a physiological range of concentrations from 10/supmore » -9/ to 10/sup -6/ M. Differences in culture age and in subclones of C6 can influence both the normal and the HC-induced pattern of GRP. The origin of the GRP is unknown, but pattern reproducibility, viability tests, surface labelling studies, and metabolic labelling studies of soluble and particulate compartment proteins and glycoproteins support the position that cell lysis is not an important source of GRP. More importantly, these studies indicate that GRP and HC-induced changes in GRP pattern are physiologically significant aspects of glial cell behavior.« less

Sleep and immune function: glial contributions and consequences of aging

PubMed Central

Ingiosi, Ashley M.; Opp, Mark R.; Krueger, James M.

2013-01-01

The reciprocal interactions between sleep and immune function are well-studied. Insufficient sleep induces innate immune responses as evidenced by increased expression of pro-inflammatory mediators in the brain and periphery. Conversely, immune challenges upregulate immunomodulator expression, which alters central nervous system-mediated processes and behaviors, including sleep. Recent studies indicate that glial cells, namely microglia and astrocytes, are active contributors to sleep and immune system interactions. Evidence suggests glial regulation of these interactions is mediated, in part, by adenosine and adenosine 5′-triphosphate actions at purinergic type 1 and type 2 receptors. Furthermore, microglia and astrocytes may modulate declines in sleep-wake behavior and immunity observed in aging. PMID:23452941

Sleep and immune function: glial contributions and consequences of aging.

PubMed

Ingiosi, Ashley M; Opp, Mark R; Krueger, James M

2013-10-01

The reciprocal interactions between sleep and immune function are well-studied. Insufficient sleep induces innate immune responses as evidenced by increased expression of pro-inflammatory mediators in the brain and periphery. Conversely, immune challenges upregulate immunomodulator expression, which alters central nervous system-mediated processes and behaviors, including sleep. Recent studies indicate that glial cells, namely microglia and astrocytes, are active contributors to sleep and immune system interactions. Evidence suggests glial regulation of these interactions is mediated, in part, by adenosine and adenosine 5'-triphosphate actions at purinergic type 1 and type 2 receptors. Furthermore, microglia and astrocytes may modulate declines in sleep-wake behavior and immunity observed in aging. Copyright © 2013. Published by Elsevier Ltd.

Glial and Neuroimmune Mechanisms as Critical Modulators of Drug Use and Abuse.

PubMed

Lacagnina, Michael J; Rivera, Phillip D; Bilbo, Staci D

2017-01-01

Drugs of abuse cause persistent alterations in synaptic plasticity that may underlie addiction behaviors. Evidence suggests glial cells have an essential and underappreciated role in the development and maintenance of drug abuse by influencing neuronal and synaptic functions in multifaceted ways. Microglia and astrocytes perform critical functions in synapse formation and refinement in the developing brain, and there is growing evidence that disruptions in glial function may be implicated in numerous neurological disorders throughout the lifespan. Linking evidence of function in health and under pathological conditions, this review will outline the glial and neuroimmune mechanisms that may contribute to drug-abuse liability, exploring evidence from opioids, alcohol, and psychostimulants. Drugs of abuse can activate microglia and astrocytes through signaling at innate immune receptors, which in turn influence neuronal function not only through secretion of soluble factors (eg, cytokines and chemokines) but also potentially through direct remodeling of the synapses. In sum, this review will argue that neural-glial interactions represent an important avenue for advancing our understanding of substance abuse disorders.

Differentiation of Drosophila glial cells.

PubMed

Sasse, Sofia; Neuert, Helen; Klämbt, Christian

2015-01-01

Glial cells are important constituents of the nervous system and a hallmark of these cells are their pronounced migratory abilities. In Drosophila, glial lineages have been well described and some of the molecular mechanisms necessary to guide migrating glial cells to their final target sites have been identified. With the onset of migration, glial cells are already specified into one of five main glial cell types. The perineurial and subperineurial glial cells are eventually located at the outer surface of the Drosophila nervous system and constitute the blood-brain barrier. The cortex glial cells ensheath all neuroblasts and their progeny and reside within the central nervous system. Astrocyte-like cells invade the neuropil to control synaptic function and ensheathing glial cells encase the entire neuropil. Within the peripheral nervous system, wrapping glial cells ensheath individual axons or axon fascicles. Here, we summarize the current knowledge on how differentiation of glial cells into the specific subtypes is orchestrated. Furthermore, we discuss sequencing data that will facilitate further analyses of glial differentiation in the fly nervous system. © 2015 Wiley Periodicals, Inc.

ATP-dependent paracrine communication between enteric neurons and glia in a primary cell culture derived from embryonic mice.

PubMed

Gomes, P; Chevalier, J; Boesmans, W; Roosen, L; van den Abbeel, V; Neunlist, M; Tack, J; Vanden Berghe, P

2009-08-01

The importance of dynamic interactions between glia and neurons is increasingly recognized, both in the central and enteric nervous system. However, apart from their protective role, little is known about enteric neuro-glia interaction. The aim was to investigate neuro-glia intercellular communication in a mouse culture model using optical techniques. Complete embryonic (E13) guts were enzymatically dissociated, seeded on coverslips and studied with immunohistochemistry and Ca(2+)-imaging. Putative progenitor-like cells (expressing both PGP9.5 and S-100) differentiated over approximately 5 days into glia or neurons expressing typical cell-specific markers. The glia-neuron ratio could be manipulated by specific supplements (N2, G5). Neurons and glia were functionally identified both by their Ca(2+)-response to either depolarization (high K(+)) or lysophosphatidic acid and by the expression of typical markers. Neurons responded to ACh, DMPP, 5-HT, ATP and electrical stimulation, while glia responded to ATP and ADPbetas. Inhibition of glial responses by MRS2179 suggests involvement of P2Y1 receptors. Neuronal stimulation also caused delayed glial responses, which were reduced by suramin and by exogenous apyrases that catalyse nucleotide breakdown. Conversely, glial responses were enhanced by ARL-67156, an ecto-ATPase inhibitor. In this mouse enteric co-culture, functional glia and neurons can be easily monitored using optical techniques. Glial cells can be activated directly by ATP or ADPbetas. Activation of neuronal cells (DMPP, K(+)) causes secondary responses in glial cells, which can be modulated by tuning ATP and ADP breakdown. This strongly supports the involvement of paracrine purinergic communication between enteric neurons and glia.

On Variations in the Level of PER in Glial Clocks of Drosophila Optic Lobe and Its Negative Regulation by PDF Signaling.

PubMed

Górska-Andrzejak, Jolanta; Chwastek, Elżbieta M; Walkowicz, Lucyna; Witek, Kacper

2018-01-01

We show that the level of the core protein of the circadian clock Period (PER) expressed by glial peripheral oscillators depends on their location in the Drosophila optic lobe. It appears to be controlled by the ventral lateral neurons (LNvs) that release the circadian neurotransmitter Pigment Dispersing Factor (PDF). We demonstrate that glial cells of the distal medulla neuropil (dMnGl) that lie in the vicinity of the PDF-releasing terminals of the LNvs possess receptors for PDF (PDFRs) and express PER at significantly higher level than other types of glia. Surprisingly, the amplitude of PER molecular oscillations in dMnGl is increased twofold in PDF-free environment, that is in Pdf 0 mutants. The Pdf 0 mutants also reveal an increased level of glia-specific protein REPO in dMnGl. The photoreceptors of the compound eye (R-cells) of the PDF-null flies, on the other hand, exhibit de-synchrony of PER molecular oscillations, which manifests itself as increased variability of PER-specific immunofluorescence among the R-cells. Moreover, the daily pattern of expression of the presynaptic protein Bruchpilot (BRP) in the lamina terminals of the R-cells is changed in Pdf 0 mutant. Considering that PDFRs are also expressed by the marginal glia of the lamina that surround the R-cell terminals, the LNv pacemakers appear to be the likely modulators of molecular cycling in the peripheral clocks of both the glial cells and the photoreceptors of the compound eye. Consequently, some form of PDF-based coupling of the glial clocks and the photoreceptors of the eye with the central LNv pacemakers must be operational.

On Variations in the Level of PER in Glial Clocks of Drosophila Optic Lobe and Its Negative Regulation by PDF Signaling

PubMed Central

Górska-Andrzejak, Jolanta; Chwastek, Elżbieta M.; Walkowicz, Lucyna; Witek, Kacper

2018-01-01

We show that the level of the core protein of the circadian clock Period (PER) expressed by glial peripheral oscillators depends on their location in the Drosophila optic lobe. It appears to be controlled by the ventral lateral neurons (LNvs) that release the circadian neurotransmitter Pigment Dispersing Factor (PDF). We demonstrate that glial cells of the distal medulla neuropil (dMnGl) that lie in the vicinity of the PDF-releasing terminals of the LNvs possess receptors for PDF (PDFRs) and express PER at significantly higher level than other types of glia. Surprisingly, the amplitude of PER molecular oscillations in dMnGl is increased twofold in PDF-free environment, that is in Pdf0 mutants. The Pdf0 mutants also reveal an increased level of glia-specific protein REPO in dMnGl. The photoreceptors of the compound eye (R-cells) of the PDF-null flies, on the other hand, exhibit de-synchrony of PER molecular oscillations, which manifests itself as increased variability of PER-specific immunofluorescence among the R-cells. Moreover, the daily pattern of expression of the presynaptic protein Bruchpilot (BRP) in the lamina terminals of the R-cells is changed in Pdf0 mutant. Considering that PDFRs are also expressed by the marginal glia of the lamina that surround the R-cell terminals, the LNv pacemakers appear to be the likely modulators of molecular cycling in the peripheral clocks of both the glial cells and the photoreceptors of the compound eye. Consequently, some form of PDF-based coupling of the glial clocks and the photoreceptors of the eye with the central LNv pacemakers must be operational. PMID:29615925

Resveratrol Confers Protection against Rotenone-Induced Neurotoxicity by Modulating Myeloperoxidase Levels in Glial Cells

PubMed Central

Chang, Chi Young; Choi, Dong-Kug; Lee, Dae Kee; Hong, Young Jun; Park, Eun Jung

2013-01-01

Myeloperoxidase (MPO) functions as a key molecular component of the host defense system against diverse pathogens. We have previously reported that increased MPO levels and activity is a distinguishing feature of rotenone-exposed glial cells, and that either overactivation or deficiency of MPO leads to pathological conditions in the brain. Here, we provide that modulation of MPO levels in glia by resveratrol confers protective effects on rotenone-induced neurotoxicity. We show that resveratrol significantly reduced MPO levels but did not trigger abnormal nitric oxide (NO) production in microglia and astrocytes. Resveratrol-induced down-regulation of MPO, in the absence of an associated overproduction of NO, markedly attenuated rotenone-triggered inflammatory responses including phagocytic activity and reactive oxygen species production in primary microglia and astrocytes. In addition, impaired responses of primary mixed glia from Mpo −/− mice to rotenone were relieved by treatment with resveratrol. We further show that rotenone-induced neuronal injury, particularly dopaminergic cell death, was attenuated by resveratrol in neuron-glia co-cultures, but not in neurons cultured alone. Similar regulatory effects of resveratrol on MPO levels were observed in microglia treated with MPP+, another Parkinson’s disease-linked neurotoxin, supporting the beneficial effects of resveratrol on the brain. Collectively, our findings provide that resveratrol influences glial responses to rotenone by regulating both MPO and NO, and thus protects against rotenone-induced neuronal injury. PMID:23593274

Spirulina non-protein components induce BDNF gene transcription via HO-1 activity in C6 glioma cells.

PubMed

Morita, Kyoji; Itoh, Mari; Nishibori, Naoyoshi; Her, Song; Lee, Mi-Sook

2015-01-01

Blue-green algae are known to contain biologically active proteins and non-protein substances and considered as useful materials for manufacturing the nutritional supplements. Particularly, Spirulina has been reported to contain a variety of antioxidants, such as flavonoids, carotenoids, and vitamin C, thereby exerting their protective effects against the oxidative damage to the cells. In addition to their antioxidant actions, polyphenolic compounds have been speculated to cause the protection of neuronal cells and the recovery of neurologic function in the brain through the production of brain-derived neurotrophic factor (BDNF) in glial cells. Then, the protein-deprived extract was prepared by removing the most part of protein components from aqueous extract of Spirulina platensis, and the effect of this extract on BDNF gene transcription was examined in C6 glioma cells. Consequently, the protein-deprived extract was shown to cause the elevation of BDNF mRNA levels following the expression of heme oxygenase-1 (HO-1) in the glioma cells. Therefore, the non-protein components of S. platensis are considered to stimulate BDNF gene transcription through the HO-1 induction in glial cells, thus proposing a potential ability of the algae to indirectly modulate the brain function through the glial cell activity.

Primary culture of glial cells from mouse sympathetic cervical ganglion: a valuable tool for studying glial cell biology.

PubMed

de Almeida-Leite, Camila Megale; Arantes, Rosa Maria Esteves

2010-12-15

Central nervous system glial cells as astrocytes and microglia have been investigated in vitro and many intracellular pathways have been clarified upon various stimuli. Peripheral glial cells, however, are not as deeply investigated in vitro despite its importance role in inflammatory and neurodegenerative diseases. Based on our previous experience of culturing neuronal cells, our objective was to standardize and morphologically characterize a primary culture of mouse superior cervical ganglion glial cells in order to obtain a useful tool to study peripheral glial cell biology. Superior cervical ganglia from neonatal C57BL6 mice were enzymatically and mechanically dissociated and cells were plated on diluted Matrigel coated wells in a final concentration of 10,000cells/well. Five to 8 days post plating, glial cell cultures were fixed for morphological and immunocytochemical characterization. Glial cells showed a flat and irregular shape, two or three long cytoplasm processes, and round, oval or long shaped nuclei, with regular outline. Cell proliferation and mitosis were detected both qualitative and quantitatively. Glial cells were able to maintain their phenotype in our culture model including immunoreactivity against glial cell marker GFAP. This is the first description of immunocytochemical characterization of mouse sympathetic cervical ganglion glial cells in primary culture. This work discusses the uses and limitations of our model as a tool to study many aspects of peripheral glial cell biology. Copyright © 2010 Elsevier B.V. All rights reserved.

Rapid modulation of the silent information regulator 1 by melatonin after hypoxia-ischemia in the neonatal rat brain.

PubMed

Carloni, Silvia; Riparini, Giulia; Buonocore, Giuseppe; Balduini, Walter

2017-10-01

Increasing evidence indicates that melatonin possesses protective effects toward different kinds of damage in various organs, including the brain. In a neonatal model of hypoxia-ischemia (HI), melatonin was neuroprotective and preserved the expression of the silent information regulator 1 (SIRT1) 24 hours after the insult. This study aimed to gain more insight into the role of SIRT1 in the protective effect of melatonin after HI by studying the early (1 hour) modulation of SIRT1 and its downstream targets, and the consequences on necrosis, apoptosis, autophagy, and glial cell activation. We found that melatonin administered 5 minutes after the ischemic insult significantly reduced necrotic cell death assessed 1 hour after its administration. In parallel, we found a reduced activation of the early phases of intrinsic apoptosis, detected by reduced BAX translocation to the mitochondria and preservation of the mitochondrial expression of cytochrome C, indicating a reduced outer mitochondrial membrane permeabilization in the melatonin-treated ischemic animals. These effects were concomitant to increased expression and activity of SIRT1, reduced expression and acetylation of p53, and increased autophagy activation. Melatonin also reduced HI-induced glial cells activation. SIRT1 was expressed in neurons after HI and melatonin but not in reactive glial cells expressing GFAP. Colocalization between SIRT1 and GFAP was found in some cells in control conditions. In summary, our results provide more insight into the connection between SIRT1 and melatonin in neuroprotection. The possibility that melatonin-induced SIRT1 activity might contribute to differentiate neuronal progenitor cells during the neurodegenerative process needs to be further investigated. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Retinal vasculopathy is reduced by dietary salt restriction: involvement of Glia, ENaCα, and the renin-angiotensin-aldosterone system.

PubMed

Deliyanti, Devy; Armani, Roksana; Casely, David; Figgett, William A; Agrotis, Alex; Wilkinson-Berka, Jennifer L

2014-09-01

Neovascularization and vaso-obliteration are vision-threatening events that develop by interactions between retinal vascular and glial cells. A high-salt diet is causal in cardiovascular and renal disease, which is linked to modulation of the renin-angiotensin-aldosterone system. However, it is not known whether dietary salt influences retinal vasculopathy and if the renin-angiotensin-aldosterone system is involved. We examined whether a low-salt (LS) diet influenced vascular and glial cell injury and the renin-angiotensin-aldosterone system in ischemic retinopathy. Pregnant Sprague Dawley rats were fed LS (0.03% NaCl) or normal salt (0.3% NaCl) diets, and ischemic retinopathy was induced in the offspring. An LS diet reduced retinal neovascularization and vaso-obliteration, the mRNA and protein levels of the angiogenic factors, vascular endothelial growth factor, and erythropoietin. Microglia, which influence vascular remodeling in ischemic retinopathy, were reduced by LS as was tumor necrosis factor-α. Macroglial Müller cells maintain the integrity of the blood-retinal barrier, and in ischemic retinopathy, LS reduced their gliosis and also vascular leakage. In retina, LS reduced mineralocorticoid receptor, angiotensin type 1 receptor, and renin mRNA levels, whereas, as expected, plasma levels of aldosterone and renin were increased. The aldosterone/mineralocorticoid receptor-sensitive epithelial sodium channel alpha (ENaCα), which is expressed in Müller cells, was increased in ischemic retinopathy and reduced by LS. In cultured Müller cells, high salt increased ENaCα, which was prevented by mineralocorticoid receptor and angiotensin type 1 receptor blockade. Conversely, LS reduced ENaCα, angiotensin type 1 receptor, and mineralocorticoid receptor expression. An LS diet reduced retinal vasculopathy, by modulating glial cell function and the retinal renin-angiotensin-aldosterone system. © 2014 American Heart Association, Inc.

Early evolution of radial glial cells in Bilateria

PubMed Central

Karl, Anett; Beckers, Patrick; Kaul-Strehlow, Sabrina; Ulbricht, Elke; Kourtesis, Ioannis; Kuhrt, Heidrun; Hausen, Harald; Reichenbach, Andreas; Bleidorn, Christoph

2017-01-01

Bilaterians usually possess a central nervous system, composed of neurons and supportive cells called glial cells. Whereas neuronal cells are highly comparable in all these animals, glial cells apparently differ, and in deuterostomes, radial glial cells are found. These particular secretory glial cells may represent the archetype of all (macro) glial cells and have not been reported from protostomes so far. This has caused controversial discussions of whether glial cells represent a homologous bilaterian characteristic or whether they (and thus, centralized nervous systems) evolved convergently in the two main clades of bilaterians. By using histology, transmission electron microscopy, immunolabelling and whole-mount in situ hybridization, we show here that protostomes also possess radial glia-like cells, which are very likely to be homologous to those of deuterostomes. Moreover, our antibody staining indicates that the secretory character of radial glial cells is maintained throughout their various evolutionary adaptations. This implies an early evolution of radial glial cells in the last common ancestor of Protostomia and Deuterostomia. Furthermore, it suggests that an intraepidermal nervous system—composed of sensory cells, neurons and radial glial cells—was probably the plesiomorphic condition in the bilaterian ancestor. PMID:28724733

[Fine structure of glial cells in the central nervous system of the tapeworm Grillotia erinaceus (Cestoda: Trypanorhyncha)].

PubMed

Biserova, N M

2008-01-01

The problem of glial cells existing in parasitic and free living flatworms is correlated with organization of parenchyma in platyhelmintes. In the contrary to the widespread opinion that myelin-like envelopes and glial cells do not exist in the nervous system of parasitic flatworms, it has been shown by ultrastructural researches that Amphilina foliacea (Cestoda, Amphilinidea) has well developed glial cells and myelin-like envelopes in the ganglia and main cords, which include both glial cells and intercellular components. The aim of our research was to reveal and investigate in details structural components corresponding to the concept of the glial cell in the CNS of Grillotia erinaceus (Cestoda: Trypanorhyncha). Three types of glial cells have been found. The first type is the fibroblast-like glial cells; cells locate in the cerebral ganglion, contain in cytoplasm and extract out fibrillar matrix, form desmosomes and have supporting function. The glial cells of the second type form myeline-like envelope of the giant axons and bulbar nerves in scolex and have laminar cytoplasm. These cells are numerous and exceed in number the neurons bodies into the nerve. The glial cells of the third type form multilayer envelopes in the main nerve cords; extra cellular fibers and gap-junctions take place between the layers. There are contacts between the glial cells of the third type and excretory epithelium but specialized contacts with neurons have been not found. The existing of glial cells in free living and parasitic flatworms is discussed.

Nonlinear Gap Junctions Enable Long-Distance Propagation of Pulsating Calcium Waves in Astrocyte Networks

PubMed Central

Goldberg, Mati; De Pittà, Maurizio; Volman, Vladislav; Berry, Hugues; Ben-Jacob, Eshel

2010-01-01

A new paradigm has recently emerged in brain science whereby communications between glial cells and neuron-glia interactions should be considered together with neurons and their networks to understand higher brain functions. In particular, astrocytes, the main type of glial cells in the cortex, have been shown to communicate with neurons and with each other. They are thought to form a gap-junction-coupled syncytium supporting cell-cell communication via propagating Ca2+ waves. An identified mode of propagation is based on cytoplasm-to-cytoplasm transport of inositol trisphosphate (IP3) through gap junctions that locally trigger Ca2+ pulses via IP3-dependent Ca2+-induced Ca2+ release. It is, however, currently unknown whether this intracellular route is able to support the propagation of long-distance regenerative Ca2+ waves or is restricted to short-distance signaling. Furthermore, the influence of the intracellular signaling dynamics on intercellular propagation remains to be understood. In this work, we propose a model of the gap-junctional route for intercellular Ca2+ wave propagation in astrocytes. Our model yields two major predictions. First, we show that long-distance regenerative signaling requires nonlinear coupling in the gap junctions. Second, we show that even with nonlinear gap junctions, long-distance regenerative signaling is favored when the internal Ca2+ dynamics implements frequency modulation-encoding oscillations with pulsating dynamics, while amplitude modulation-encoding dynamics tends to restrict the propagation range. As a result, spatially heterogeneous molecular properties and/or weak couplings are shown to give rise to rich spatiotemporal dynamics that support complex propagation behaviors. These results shed new light on the mechanisms implicated in the propagation of Ca2+ waves across astrocytes and the precise conditions under which glial cells may participate in information processing in the brain. PMID:20865153

Astrocytes Can Adopt Endothelial Cell Fates in a p53-Dependent Manner.

PubMed

Brumm, Andrew J; Nunez, Stefanie; Doroudchi, Mehdi M; Kawaguchi, Riki; Duan, Jinhzu; Pellegrini, Matteo; Lam, Larry; Carmichael, S Thomas; Deb, Arjun; Hinman, Jason D

2017-08-01

Astrocytes respond to a variety of CNS injuries by cellular enlargement, process outgrowth, and upregulation of extracellular matrix proteins that function to prevent expansion of the injured region. This astrocytic response, though critical to the acute injury response, results in the formation of a glial scar that inhibits neural repair. Scar-forming cells (fibroblasts) in the heart can undergo mesenchymal-endothelial transition into endothelial cell fates following cardiac injury in a process dependent on p53 that can be modulated to augment cardiac repair. Here, we sought to determine whether astrocytes, as the primary scar-forming cell of the CNS, are able to undergo a similar cellular phenotypic transition and adopt endothelial cell fates. Serum deprivation of differentiated astrocytes resulted in a change in cellular morphology and upregulation of endothelial cell marker genes. In a tube formation assay, serum-deprived astrocytes showed a substantial increase in vessel-like morphology that was comparable to human umbilical vein endothelial cells and dependent on p53. RNA sequencing of serum-deprived astrocytes demonstrated an expression profile that mimicked an endothelial rather than astrocyte transcriptome and identified p53 and angiogenic pathways as specifically upregulated. Inhibition of p53 with genetic or pharmacologic strategies inhibited astrocyte-endothelial transition. Astrocyte-endothelial cell transition could also be modulated by miR-194, a microRNA downstream of p53 that affects expression of genes regulating angiogenesis. Together, these studies demonstrate that differentiated astrocytes retain a stimulus-dependent mechanism for cellular transition into an endothelial phenotype that may modulate formation of the glial scar and promote injury-induced angiogenesis.

Adult oligodendrocyte progenitor cells - multifaceted regulators of the CNS in health and disease

PubMed Central

Fernandez-Castaneda, Anthony; Gaultier, Alban

2016-01-01

Oligodendrocyte progenitor cells (OPCs) are the often-overlooked fourth glial cell type in the central nervous system (CNS), comprising about 5% of the CNS. For a long time, our vision of OPC function was limited to the generation of mature oligodendrocytes. However, new studies have highlighted the multifaceted nature of the OPCs. During homeostatic and pathological conditions, OPCs are the most proliferative cell type in the CNS, a property not consistent with the need to generate new oligodendrocytes. Indeed, OPCs modulate neuronal activity and OPC depletion in the brain can trigger depressive-like behavior. More importantly, OPCs are actively recruited to injury sites, where they orchestrate glial scar formation and contribute to the immune response. The following is a comprehensive analysis of the literature on OPC function beyond myelination, in the context of the healthy and diseased adult CNS. PMID:26796621

Expression of membrane progesterone receptors (mPRs) in rat peripheral glial cell membranes and their potential role in the modulation of cell migration and protein expression.

PubMed

Castelnovo, Luca F; Magnaghi, Valerio; Thomas, Peter

2017-09-28

The role played by progestogens in modulating Schwann cell pathophysiology is well established. Progestogens exert their effects in these cells through both classical genomic and non-genomic mechanisms, the latter mediated by the GABA-A receptor. However, there is evidence that other receptors may be involved. Membrane progesterone receptors (mPRs) are novel 7-transmembrane receptors coupled to G proteins that have been characterized in different tissues and cells, including the central nervous system (CNS). The mPRs were shown to mediate some of progestogens' neuroprotective effects in the CNS, and to be upregulated in glial cells after traumatic brain injury. Based on this evidence, this paper investigated the possible involvement of mPRs in mediating progestogen actions in S42 Schwann cells. All five mPR isoforms and progesterone receptor membrane component 1 (PGRMC1) were detected in Schwann cells, and were present on the cell membrane. Progesterone and the mPR-specific agonist, Org-OD-02-0 (02) bound to these membranes, indicating the presence of functional mPRs. The mPR agonist 02 rapidly increased cell migration in an in vitro assay, suggesting a putative role of mPRs in the nerve regeneration process. Treatment with pertussis toxin and 8-Br-cAMP blocked 02-induced cell migration, suggesting this progestogen action is mediated by activation of an inhibitory G protein, leading to a decrease in intracellular cAMP levels. In contrast, long-term mPR activation led to increased expression levels of myelin associated glycoprotein (MAG). Taken together, these findings show that mPRs are present and active in Schwann cells and have a role in modulating their physiological processes. Copyright © 2017 Elsevier Inc. All rights reserved.

NG2 glial cells regulate neuroimmunological responses to maintain neuronal function and survival.

PubMed

Nakano, Masayuki; Tamura, Yasuhisa; Yamato, Masanori; Kume, Satoshi; Eguchi, Asami; Takata, Kumi; Watanabe, Yasuyoshi; Kataoka, Yosky

2017-02-14

NG2-expressing neural progenitor cells (i.e., NG2 glial cells) maintain their proliferative and migratory activities even in the adult mammalian central nervous system (CNS) and produce myelinating oligodendrocytes and astrocytes. Although NG2 glial cells have been observed in close proximity to neuronal cell bodies in order to receive synaptic inputs, substantive non-proliferative roles of NG2 glial cells in the adult CNS remain unclear. In the present study, we generated NG2-HSVtk transgenic rats and selectively ablated NG2 glial cells in the adult CNS. Ablation of NG2 glial cells produced defects in hippocampal neurons due to excessive neuroinflammation via activation of the interleukin-1 beta (IL-1β) pro-inflammatory pathway, resulting in hippocampal atrophy. Furthermore, we revealed that the loss of NG2 glial cell-derived hepatocyte growth factor (HGF) exacerbated these abnormalities. Our findings suggest that NG2 glial cells maintain neuronal function and survival via the control of neuroimmunological function.

Reactive glia promote development of CD103+ CD69+ CD8+ T-cells through programmed cell death-ligand 1 (PD-L1).

PubMed

Prasad, Sujata; Hu, Shuxian; Sheng, Wen S; Chauhan, Priyanka; Lokensgard, James R

2018-06-01

Previous work from our laboratory has demonstrated in vivo persistence of CD103 + CD69 + brain resident memory CD8 + T-cells (bT RM ) following viral infection, and that the PD-1: PD-L1 pathway promotes development of these T RM cells within the brain. Although glial cells express low basal levels of PD-L1, its expression is upregulated upon IFN-γ-treatment, and they have been shown to modulate antiviral T-cell effector responses through the PD-1: PD-L1 pathway. We performed flow cytometric analysis of cells from co-cultures of mixed glia and CD8 + T-cells obtained from wild type mice to investigate the role of glial cells in the development of bT RM . In this study, we show that interactions between reactive glia and anti-CD3 Ab-stimulated CD8 + T-cells promote development of CD103 + CD69 + CD8 + T-cells through engagement of the PD-1: PD-L1 pathway. These studies used co-cultures of primary murine glial cells obtained from WT animals along with CD8 + T-cells obtained from either WT or PD-1 KO mice. We found that αCD3 Ab-stimulated CD8 + T-cells from WT animals increased expression of CD103 and CD69 when co-cultured with primary murine glial cells. In contrast, significantly reduced expression of CD103 and CD69 was observed using CD8 + T-cells from PD-1 KO mice. We also observed that reactive glia promoted high levels of CD127, a marker of memory precursor effector cells (MPEC), on CD69 + CD8 + T-cells, which promotes development of T RM cells. Interestingly, results obtained using T-cells from PD-1 KO animals showed significantly reduced expression of CD127 on CD69 + CD8 + cells. Additionally, blocking of glial PD-L1 resulted in decreased expression of CD103, along with reduced CD127 on CD69 + CD8 + T-cells. Taken together, these results demonstrate a role for activated glia in promoting development of bT RM through the PD-1: PD-L1 pathway. © 2018 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.

Age-Dependent Netrin-1 Signaling Regulates NG2+ Glial Cell Spatial Homeostasis in Normal Adult Gray Matter

PubMed Central

Birey, Fikri

2015-01-01

Neuron–glial antigen 2-positive (NG2+) glial cells are the most proliferative glia type in the adult CNS, and their tile-like arrangement in adult gray matter is under tight regulation. However, little is known about the cues that govern this unique distribution. To this end, using a NG2+ glial cell ablation model in mice, we examined the repopulation dynamics of NG2+ glial cells in the mature and aged mice gray matter. We found that some resident NG2+ glial cells that escaped depletion rapidly enter the cell cycle to repopulate the cortex with altered spatial distribution. We reveal that netrin-1 signaling is involved in the NG2+ glial cell early proliferative, late repopulation, and distribution response after ablation in the gray matter. However, ablation of NG2+ glial cell in older animals failed to stimulate a similar repopulation response, possibly because of a decrease in the sensitivity to netrin-1. Our findings indicate that endogenous netrin-1 plays a role in NG2+ glial cell homeostasis that is distinct from its role in myelination. PMID:25926469

RCCS bioreactor-based modelled microgravity induces significant changes on in vitro 3D neuroglial cell cultures.

PubMed

Morabito, Caterina; Steimberg, Nathalie; Mazzoleni, Giovanna; Guarnieri, Simone; Fanò-Illic, Giorgio; Mariggiò, Maria A

2015-01-01

We propose a human-derived neuro-/glial cell three-dimensional in vitro model to investigate the effects of microgravity on cell-cell interactions. A rotary cell-culture system (RCCS) bioreactor was used to generate a modelled microgravity environment, and morphofunctional features of glial-like GL15 and neuronal-like SH-SY5Y cells in three-dimensional individual cultures (monotypic aggregates) and cocultures (heterotypic aggregates) were analysed. Cell survival was maintained within all cell aggregates over 2 weeks of culture. Moreover, compared to cells as traditional static monolayers, cell aggregates cultured under modelled microgravity showed increased expression of specific differentiation markers (e.g., GL15 cells: GFAP, S100B; SH-SY5Y cells: GAP43) and modulation of functional cell-cell interactions (e.g., N-CAM and Cx43 expression and localisation). In conclusion, this culture model opens a wide range of specific investigations at the molecular, biochemical, and morphological levels, and it represents an important tool for in vitro studies into dynamic interactions and responses of nervous system cell components to microgravity environmental conditions.

RCCS Bioreactor-Based Modelled Microgravity Induces Significant Changes on In Vitro 3D Neuroglial Cell Cultures

PubMed Central

Mazzoleni, Giovanna; Fanò-Illic, Giorgio; Mariggiò, Maria A.

2015-01-01

We propose a human-derived neuro-/glial cell three-dimensional in vitro model to investigate the effects of microgravity on cell-cell interactions. A rotary cell-culture system (RCCS) bioreactor was used to generate a modelled microgravity environment, and morphofunctional features of glial-like GL15 and neuronal-like SH-SY5Y cells in three-dimensional individual cultures (monotypic aggregates) and cocultures (heterotypic aggregates) were analysed. Cell survival was maintained within all cell aggregates over 2 weeks of culture. Moreover, compared to cells as traditional static monolayers, cell aggregates cultured under modelled microgravity showed increased expression of specific differentiation markers (e.g., GL15 cells: GFAP, S100B; SH-SY5Y cells: GAP43) and modulation of functional cell-cell interactions (e.g., N-CAM and Cx43 expression and localisation). In conclusion, this culture model opens a wide range of specific investigations at the molecular, biochemical, and morphological levels, and it represents an important tool for in vitro studies into dynamic interactions and responses of nervous system cell components to microgravity environmental conditions. PMID:25654124

Activation of glial FGFRs is essential in glial migration, proliferation, and survival and in glia-neuron signaling during olfactory system development.

PubMed

Gibson, Nicholas J; Tolbert, Leslie P; Oland, Lynne A

2012-01-01

Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells.

Activation of Glial FGFRs Is Essential in Glial Migration, Proliferation, and Survival and in Glia-Neuron Signaling during Olfactory System Development

PubMed Central

Gibson, Nicholas J.; Tolbert, Leslie P.; Oland, Lynne A.

2012-01-01

Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells. PMID:22493675

Glial S100B protein modulates mutant ataxin-1 aggregation and toxicity: TRTK12 peptide, a potential candidate for SCA1 therapy.

PubMed

Vig, Parminder J S; Hearst, Scoty; Shao, Qingmei; Lopez, Mariper E; Murphy, Henry A; Safaya, Eshan

2011-06-01

Non-cell autonomous involvement of glial cells in the pathogenesis of polyglutamine diseases is gaining recognition in the ataxia field. We previously demonstrated that Purkinje cells (PCs) in polyglutamine disease spinocerebellar ataxia-1 (SCA1) contain cytoplasmic vacuoles rich in Bergmann glial protein S100B. The vacuolar formation in SCA1 PCs is accompanied with an abnormal morphology of dendritic spines. In addition, S100B messenger RNA (mRNA) expression levels are significantly high in the cerebella of asymptomatic SCA1 transgenic (Tg) mice and increase further with age when compared with the age-matched wild-type animals. This higher S100B mRNA expression positively correlates with an increase in the number of vacuoles. To further characterize the function of S100B in SCA1 pathology, we explored the effects of S100B protein on GFP-ataxin-1 (ATXN1) with expanded polyglutamines [82Q] in HEK stable cell line. Externally added S100B protein to these cells induced S100B-positive vacuoles similar to those seen in SCA1 PCs in vivo. Further, we found that both externally added and internally expressed S100B significantly reduced GFP-ATXN1[82Q] inclusion body formation. In contrast, the addition of S100B inhibitory peptide TRTK12 reversed S100B-mediated effects. Interestingly, in SCA1 Tg mice, PCs containing S100B vacuoles also showed the lack of nuclear inclusions, whereas PCs without vacuoles contained nuclear inclusions. Additionally, TRTK12 treatment reduced abnormal dendritic growth and morphology of PCs in cerebellar slice cultures prepared from SCA1 Tg mice. Moreover, intranasal administration of TRTK12 to SCA1 Tg mice reduced cerebellar S100B levels in the particulate fractions, and these mice displayed a significant improvement in their performance deficit on the Rotarod test. Taken together, our results suggest that glial S100B may augment degenerative changes in SCA1 PCs by modulating mutant ataxin-1 toxicity/solubility through an unknown signaling pathway.

Glial S100B protein modulates mutant ataxin-1 aggregation and toxicity: TRTK12 peptide, a potential candidate for SCA1 therapy

PubMed Central

Vig, Parminder J.S.; Hearst, Scoty; Shao, Qingmei; Lopez, Maripar E; Murphy, Henry A; Safaya, Eshan

2011-01-01

Non-cell autonomous involvement of glial cells in the pathogenesis of polyglutamine diseases is gaining recognition in the ataxia field. We previously demonstrated that Purkinje cells (PCs) in polyglutamine disease spinocerebellar ataxia-1 (SCA1) contain cytoplasmic vacuoles rich in Bergmann glial (BG) protein S100B. The vacuolar formation in SCA1 PCs is accompanied with an abnormal morphology of dendritic spines. In addition, S100B mRNA expression levels are significantly high in the cerebella of asymptomatic SCA1 transgenic (Tg) mice and increase further with age when compared with the age-matched wildtype animals. This higher S100B mRNA expression positively correlates with an increase in the number of vacuoles. To further characterize the function of S100B in SCA1 pathology, we explored the effects of S100B protein on GFP-ataxin-1 (ATXN1) with expanded polyglutamines [82Q] in HEK stable cell line. Externally added S100B protein to these cells induced S100B positive vacuoles similar to those seen in SCA1 PCs in vivo. Further, we found that both externally added and internally expressed S100B significantly reduced GFP-ATXN1[82Q] inclusion body formation. In contrast, the addition of S100B inhibitory peptide TRTK12 reversed S100B mediated effects. Interestingly, in SCA1 Tg mice, PCs containing S100B vacuoles also showed the lack of nuclear inclusions, whereas, PCs without vacuoles contained nuclear inclusions. Additionally, TRTK12 treatment reduced abnormal dendritic growth and morphology of PCs in cerebellar slice cultures prepared from SCA1 Tg mice. Moreover, intranasal administration of TRTK12 to SCA1 Tg mice reduced cerebellar S100B levels in the particulate fractions and these mice displayed a significant improvement in their performance deficit on the Rotarod test. Taken together our results suggest that glial S100B may augment degenerative changes in SCA1 PCs by modulating mutant ataxin-1 toxicity/solubility through an unknown signaling pathway. PMID:21384195

Age-Dependent Netrin-1 Signaling Regulates NG2+ Glial Cell Spatial Homeostasis in Normal Adult Gray Matter.

PubMed

Birey, Fikri; Aguirre, Adan

2015-04-29

Neuron-glial antigen 2-positive (NG2(+)) glial cells are the most proliferative glia type in the adult CNS, and their tile-like arrangement in adult gray matter is under tight regulation. However, little is known about the cues that govern this unique distribution. To this end, using a NG2(+) glial cell ablation model in mice, we examined the repopulation dynamics of NG2(+) glial cells in the mature and aged mice gray matter. We found that some resident NG2(+) glial cells that escaped depletion rapidly enter the cell cycle to repopulate the cortex with altered spatial distribution. We reveal that netrin-1 signaling is involved in the NG2(+) glial cell early proliferative, late repopulation, and distribution response after ablation in the gray matter. However, ablation of NG2(+) glial cell in older animals failed to stimulate a similar repopulation response, possibly because of a decrease in the sensitivity to netrin-1. Our findings indicate that endogenous netrin-1 plays a role in NG2(+) glial cell homeostasis that is distinct from its role in myelination. Copyright © 2015 the authors 0270-6474/15/356946-06$15.00/0.

Driver or passenger effects of augmented c-Myc and Cdc20 in gliomagenesis.

PubMed

Ji, Ping; Zhou, Xinhui; Liu, Qun; Fuller, Gregory N; Phillips, Lynette M; Zhang, Wei

2016-04-26

Cdc20 and c-Myc are commonly overexpressed in a broad spectrum of cancers, including glioblastoma (GBM). Despite this clear association, whether c-Myc and Cdc20 overexpression is a driver or passenger event in gliomagenesis remains unclear. Both c-Myc and Cdc20 induced the proliferation of primary glial progenitor cells. c-Myc also promoted the formation of soft agar anchorage-independent colonies. In the RCAS/Ntv-a glia-specific transgenic mouse model, c-Myc increased the GBM incidence from 19.1% to 47.4% by 12 weeks of age when combined with kRas and Akt3 in Ntv-a INK4a-ARF (also known as CDKN2A)-null mice. In contrast, Cdc20 decreased the GBM incidence from 19.1% to 9.1%. Moreover, cell differentiation was modulated by c-Myc in kRas/Akt3-induced GBM on the basis of Nestin/GFAP expression (glial progenitor cell differentiation), while Cdc20 had no effect on primary glial progenitor cell differentiation. We used glial progenitor cells from Ntv-a newborn mice to evaluate the role of c-Myc and Cdc20 in the proliferation and transformation of GBM in vitro and in vivo. We further determined whether c-Myc and Cdc20 have a driver or passenger role in GBM development using kRas/Akt3 signals in a RCAS/Ntv-a mouse model. These results suggest that the driver or passenger of oncogene signaling is dependent on cellular status. c-Myc is a driver when combined with kRas/Akt3 oncogenic signals in gliomagenesis, whereas Cdc20 overexpression is a passenger. Inhibition of cell differentiation of c-Myc may be a target for anti-glioma therapy.

Arrays of MicroLEDs and Astrocytes: Biological Amplifiers to Optogenetically Modulate Neuronal Networks Reducing Light Requirement

PubMed Central

Berlinguer-Palmini, Rolando; Narducci, Roberto; Merhan, Kamyar; Dilaghi, Arianna; Moroni, Flavio; Masi, Alessio; Scartabelli, Tania; Landucci, Elisa; Sili, Maria; Schettini, Antonio; McGovern, Brian; Maskaant, Pleun; Degenaar, Patrick; Mannaioni, Guido

2014-01-01

In the modern view of synaptic transmission, astrocytes are no longer confined to the role of merely supportive cells. Although they do not generate action potentials, they nonetheless exhibit electrical activity and can influence surrounding neurons through gliotransmitter release. In this work, we explored whether optogenetic activation of glial cells could act as an amplification mechanism to optical neural stimulation via gliotransmission to the neural network. We studied the modulation of gliotransmission by selective photo-activation of channelrhodopsin-2 (ChR2) and by means of a matrix of individually addressable super-bright microLEDs (μLEDs) with an excitation peak at 470 nm. We combined Ca2+ imaging techniques and concurrent patch-clamp electrophysiology to obtain subsequent glia/neural activity. First, we tested the μLEDs efficacy in stimulating ChR2-transfected astrocyte. ChR2-induced astrocytic current did not desensitize overtime, and was linearly increased and prolonged by increasing μLED irradiance in terms of intensity and surface illumination. Subsequently, ChR2 astrocytic stimulation by broad-field LED illumination with the same spectral profile, increased both glial cells and neuronal calcium transient frequency and sEPSCs suggesting that few ChR2-transfected astrocytes were able to excite surrounding not-ChR2-transfected astrocytes and neurons. Finally, by using the μLEDs array to selectively light stimulate ChR2 positive astrocytes we were able to increase the synaptic activity of single neurons surrounding it. In conclusion, ChR2-transfected astrocytes and μLEDs system were shown to be an amplifier of synaptic activity in mixed corticalneuronal and glial cells culture. PMID:25265500

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koike, Taro, E-mail: koiket@hirakata.kmu.ac.jp; Wakabayashi, Taketoshi; Mori, Tetsuji

Sox2 is a transcriptional factor expressed in neural stem cells. It is known that Sox2 regulates cell differentiation, proliferation and survival of the neural stem cells. Our previous study showed that Sox2 is expressed in all satellite glial cells of the adult rat dorsal root ganglion. In this study, to examine the role of Sox2 in satellite glial cells, we establish a satellite glial cell-enriched culture system. Our culture method succeeded in harvesting satellite glial cells with the somata of neurons in the dorsal root ganglion. Using this culture system, Sox2 was downregulated by siRNA against Sox2. The knockdown ofmore » Sox2 downregulated ErbB2 and ErbB3 mRNA at 2 and 4 days after siRNA treatment. MAPK phosphorylation, downstream of ErbB, was also inhibited by Sox2 knockdown. Because ErbB2 and ErbB3 are receptors that support the survival of glial cells in the peripheral nervous system, apoptotic cells were also counted. TUNEL-positive cells increased at 5 days after siRNA treatment. These results suggest that Sox2 promotes satellite glial cell survival through the MAPK pathway via ErbB receptors. - Highlights: • We established satellite glial cell culture system. • Function of Sox2 in satellite glial cell was examined using siRNA. • Sox2 knockdown downregulated expression level of ErbB2 and ErbB3 mRNA. • Sox2 knockdown increased apoptotic satellite glial cell. • Sox2 promotes satellite glial cell survival through ErbB signaling.« less

Texturing Silicon Nanowires for Highly Localized Optical Modulation of Cellular Dynamics.

PubMed

Fang, Yin; Jiang, Yuanwen; Acaron Ledesma, Hector; Yi, Jaeseok; Gao, Xiang; Weiss, Dara E; Shi, Fengyuan; Tian, Bozhi

2018-06-18

Engineered silicon-based materials can display photoelectric and photothermal responses under light illumination, which may lead to further innovations at the silicon-biology interfaces. Silicon nanowires have small radial dimensions, promising as highly localized cellular modulators, however the single crystalline form typically has limited photothermal efficacy due to the poor light absorption and fast heat dissipation. In this work, we report strategies to improve the photothermal response from silicon nanowires by introducing nanoscale textures on the surface and in the bulk. We next demonstrate high-resolution extracellular modulation of calcium dynamics in a number of mammalian cells including glial cells, neurons, and cancer cells. The new materials may be broadly used in probing and modulating electrical and chemical signals at the subcellular length scale, which is currently a challenge in the field of electrophysiology or cellular engineering.

All brains are made of this: a fundamental building block of brain matter with matching neuronal and glial masses.

PubMed

Mota, Bruno; Herculano-Houzel, Suzana

2014-01-01

How does the size of the glial and neuronal cells that compose brain tissue vary across brain structures and species? Our previous studies indicate that average neuronal size is highly variable, while average glial cell size is more constant. Measuring whole cell sizes in vivo, however, is a daunting task. Here we use chi-square minimization of the relationship between measured neuronal and glial cell densities in the cerebral cortex, cerebellum, and rest of brain in 27 mammalian species to model neuronal and glial cell mass, as well as the neuronal mass fraction of the tissue (the fraction of tissue mass composed by neurons). Our model shows that while average neuronal cell mass varies by over 500-fold across brain structures and species, average glial cell mass varies only 1.4-fold. Neuronal mass fraction varies typically between 0.6 and 0.8 in all structures. Remarkably, we show that two fundamental, universal relationships apply across all brain structures and species: (1) the glia/neuron ratio varies with the total neuronal mass in the tissue (which in turn depends on variations in average neuronal cell mass), and (2) the neuronal mass per glial cell, and with it the neuronal mass fraction and neuron/glia mass ratio, varies with average glial cell mass in the tissue. We propose that there is a fundamental building block of brain tissue: the glial mass that accompanies a unit of neuronal mass. We argue that the scaling of this glial mass is a consequence of a universal mechanism whereby numbers of glial cells are added to the neuronal parenchyma during development, irrespective of whether the neurons composing it are large or small, but depending on the average mass of the glial cells being added. We also show how evolutionary variations in neuronal cell mass, glial cell mass and number of neurons suffice to determine the most basic characteristics of brain structures, such as mass, glia/neuron ratio, neuron/glia mass ratio, and cell densities.

Age-related changes in the hippocampus (loss of synaptophysin and glial-synaptic interaction) are modified by systemic treatment with an NCAM-derived peptide, FGL.

PubMed

Ojo, Bunmi; Rezaie, Payam; Gabbott, Paul L; Davies, Heather; Colyer, Frances; Cowley, Thelma R; Lynch, Marina; Stewart, Michael G

2012-07-01

Altered synaptic morphology, progressive loss of synapses and glial (astrocyte and microglial) cell activation are considered as characteristic hallmarks of aging. Recent evidence suggests that there is a concomitant age-related decrease in expression of the presynaptic protein, synaptophysin, and the neuronal glycoprotein CD200, which, by interacting with its receptor, plays a role in maintaining microglia in a quiescent state. These age-related changes may be indicative of reduced neuroglial support of synapses. FG Loop (FGL) peptide synthesized from the second fibronectin type III module of neural cell adhesion molecule (NCAM), has previously been shown to attenuate age-related glial cell activation, and to 'restore' cognitive function in aged rats. The mechanisms by which FGL exerts these neuroprotective effects remain unclear, but could involve regulation of CD200, modifying glial-synaptic interactions (affecting neuroglial 'support' at synapses), or impacting directly on synaptic function. Light and electron microscopic (EM) analyses were undertaken to investigate whether systemic treatment with FGL (i) alters CD200, synaptophysin (presynaptic) and PSD-95 (postsynaptic) immunohistochemical expression levels, (ii) affects synaptic number, or (iii) exerts any effects on glial-synaptic interactions within young (4 month-old) and aged (22 month-old) rat hippocampus. Treatment with FGL attenuated the age-related loss of synaptophysin immunoreactivity (-ir) within CA3 and hilus (with no major effect on PSD-95-ir), and of CD200-ir specifically in the CA3 region. Ultrastructural morphometric analyses showed that FGL treatment (i) prevented age-related loss in astrocyte-synaptic contacts, (ii) reduced microglia-synaptic contacts in the CA3 stratum radiatum, but (iii) had no effect on the mean number of synapses in this region. These data suggest that FGL mediates its neuroprotective effects by regulating glial-synaptic interaction. Copyright © 2011 Elsevier Inc. All rights reserved.

Heterotypic binding between neuronal membrane vesicles and glial cells is mediated by a specific cell adhesion molecule

PubMed Central

1984-01-01

By means of a multistage quantitative assay, we have identified a new kind of cell adhesion molecule (CAM) on neuronal cells of the chick embryo that is involved in their adhesion to glial cells. The assay used to identify the binding component (which we name neuron-glia CAM or Ng-CAM) was designed to distinguish between homotypic binding (e.g., neuron to neuron) and heterotypic binding (e.g., neuron to glia). This distinction was essential because a single neuron might simultaneously carry different CAMs separately mediating each of these interactions. The adhesion of neuronal cells to glial cells in vitro was previously found to be inhibited by Fab' fragments prepared from antisera against neuronal membranes but not by Fab' fragments against N-CAM, the neural cell adhesion molecule. This suggested that neuron-glia adhesion is mediated by specific cell surface molecules different from previously isolated CAMs . To verify that this was the case, neuronal membrane vesicles were labeled internally with 6-carboxyfluorescein and externally with 125I-labeled antibodies to N-CAM to block their homotypic binding. Labeled vesicles bound to glial cells but not to fibroblasts during a 30-min incubation period. The specific binding of the neuronal vesicles to glial cells was measured by fluorescence microscopy and gamma spectroscopy of the 125I label. Binding increased with increasing concentrations of both glial cells and neuronal vesicles. Fab' fragments prepared from anti-neuronal membrane sera that inhibited binding between neurons and glial cells were also found to inhibit neuronal vesicle binding to glial cells. The inhibitory activity of the Fab' fragments was depleted by preincubation with neuronal cells but not with glial cells. Trypsin treatment of neuronal membrane vesicles released material that neutralized Fab' fragment inhibition; after chromatography, neutralizing activity was enriched 50- fold. This fraction was injected into mice to produce monoclonal antibodies; an antibody was obtained that interacted with neurons, inhibited binding of neuronal membrane vesicles to glial cells, and recognized an Mr = 135,000 band in immunoblots of embryonic chick brain membranes. These results suggest that this molecule is present on the surfaces of neurons and that it directly or indirectly mediates adhesion between neurons and glial cells. Because the monoclonal antibody as well as the original polyspecific antibodies that were active in the assay did not bind to glial cells, we infer that neuron- glial interaction is heterophilic, i.e., it occurs between Ng-CAM on neurons and an as yet unidentified CAM present on glial cells. PMID:6725397

Oxytocin signaling in mouse taste buds.

PubMed

Sinclair, Michael S; Perea-Martinez, Isabel; Dvoryanchikov, Gennady; Yoshida, Masahide; Nishimori, Katsuhiko; Roper, Stephen D; Chaudhari, Nirupa

2010-08-05

The neuropeptide, oxytocin (OXT), acts on brain circuits to inhibit food intake. Mutant mice lacking OXT (OXT knockout) overconsume salty and sweet (i.e. sucrose, saccharin) solutions. We asked if OXT might also act on taste buds via its receptor, OXTR. Using RT-PCR, we detected the expression of OXTR in taste buds throughout the oral cavity, but not in adjacent non-taste lingual epithelium. By immunostaining tissues from OXTR-YFP knock-in mice, we found that OXTR is expressed in a subset of Glial-like (Type I) taste cells, and also in cells on the periphery of taste buds. Single-cell RT-PCR confirmed this cell-type assignment. Using Ca2+ imaging, we observed that physiologically appropriate concentrations of OXT evoked [Ca2+]i mobilization in a subset of taste cells (EC50 approximately 33 nM). OXT-evoked responses were significantly inhibited by the OXTR antagonist, L-371,257. Isolated OXT-responsive taste cells were neither Receptor (Type II) nor Presynaptic (Type III) cells, consistent with our immunofluorescence observations. We also investigated the source of OXT peptide that may act on taste cells. Both RT-PCR and immunostaining suggest that the OXT peptide is not produced in taste buds or in their associated nerves. Finally, we also examined the morphology of taste buds from mice that lack OXTR. Taste buds and their constituent cell types appeared very similar in mice with two, one or no copies of the OXTR gene. We conclude that OXT elicits Ca2+ signals via OXTR in murine taste buds. OXT-responsive cells are most likely a subset of Glial-like (Type I) taste cells. OXT itself is not produced locally in taste tissue and is likely delivered through the circulation. Loss of OXTR does not grossly alter the morphology of any of the cell types contained in taste buds. Instead, we speculate that OXT-responsive Glial-like (Type I) taste bud cells modulate taste signaling and afferent sensory output. Such modulation would complement central pathways of appetite regulation that employ circulating homeostatic and satiety signals.

Purinergic Modulation of Spinal Neuroglial Maladaptive Plasticity Following Peripheral Nerve Injury.

PubMed

Cirillo, Giovanni; Colangelo, Anna Maria; Berbenni, Miluscia; Ippolito, Vita Maria; De Luca, Ciro; Verdesca, Francesco; Savarese, Leonilde; Alberghina, Lilia; Maggio, Nicola; Papa, Michele

2015-12-01

Modulation of spinal reactive gliosis following peripheral nerve injury (PNI) is a promising strategy to restore synaptic homeostasis. Oxidized ATP (OxATP), a nonselective antagonist of purinergic P2X receptors, was found to recover a neuropathic behavior following PNI. We investigated the role of intraperitoneal (i.p.) OxATP treatment in restoring the expression of neuronal and glial markers in the mouse spinal cord after sciatic spared nerve injury (SNI). Using in vivo two-photon microscopy, we imaged Ca(2+) transients in neurons and astrocytes of the dorsal horn of spinal cord at rest and upon right hind paw electrical stimulation in sham, SNI, and OxATP-treated mice. Neuropathic behavior was investigated by von Frey and thermal plantar test. Glial [glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule 1 (Iba1)] and GABAergic [vesicular GABA transporter (vGAT) and glutamic acid decarboxylase 65/76 (GAD65/67)] markers and glial [glutamate transporter (GLT1) and GLAST] and neuronal amino acid [EAAC1, vesicular glutamate transporter 1 (vGLUT1)] transporters have been evaluated. In SNI mice, we found (i) increased glial response, (ii) decreased glial amino acid transporters, and (iii) increased levels of neuronal amino acid transporters, and (iv) in vivo analysis of spinal neurons and astrocytes showed a persistent increase of Ca(2+) levels. OxATP administration reduced glial activation, modulated the expression of glial and neuronal glutamate/GABA transporters, restored neuronal and astrocytic Ca(2+) levels, and prevented neuropathic behavior. In vitro studies validated that OxATP (i) reduced levels of reactive oxygen species (ROS), (ii) reduced astrocytic proliferation, (iii) increase vGLUT expression. All together, these data support the correlation between reactive gliosis and perturbation of the spinal synaptic homeostasis and the role played by the purinergic system in modulating spinal plasticity following PNI.

Photodynamic damage of glial cells in crayfish ventral nerve cord

NASA Astrophysics Data System (ADS)

Kolosov, M. S.; Duz, E.; Uzdensky, A. B.

2011-03-01

Photodynamic therapy (PDT) is a promising method for treatment of brain tumors, the most of which are of glial origin. In the present work we studied PDT-mediated injury of glial cells in nerve tissue, specifically, in abdominal connectives in the crayfish ventral nerve cord. The preparation was photosensitized with alumophthalocyanine Photosens and irradiated 30 min with the diode laser (670 nm, 0.1 or 0.15 W/cm2). After following incubation in the darkness during 1- 10 hours it was fluorochromed with Hoechst 33342 and propidium iodide to reveal nuclei of living, necrotic and apoptotic cells. The chain-like location of the glial nuclei allowed visualization of those enveloping giant axons and blood vessels. The level of glial necrosis in control preparations was about 2-5 %. Apoptosis was not observed in control preparations. PDT significantly increased necrosis of glial cells to 52 or 67 % just after irradiation with 0.1 or 0.15 W/cm2, respectively. Apoptosis of glial cells was observed only at 10 hours after light exposure. Upper layers of the glial envelope of the connectives were injured stronger comparing to deep ones: the level of glial necrosis decreased from 100 to 30 % upon moving from the connective surface to the plane of the giant axon inside the connective. Survival of glial cells was also high in the vicinity of blood vessels. One can suggest that giant axons and blood vessels protect neighboring glial cells from photodynamic damage. The mechanism of such protective action remains to be elucidated.

Idiopathic preretinal glia in aging and age-related macular degeneration

PubMed Central

Edwards, Malia M.; McLeod, D. Scott; Bhutto, Imran A.; Villalonga, Mercedes B.; Seddon, Johanna M.; Lutty, Gerard A.

2015-01-01

During analysis of glia in wholemount aged human retinas, frequent projections onto the vitreal surface of the inner limiting membrane (ILM) were noted. The present study characterized these preretinal glial structures. The amount of glial cells on the vitreal side of the ILM was compared between eyes with age-related macular degeneration (AMD) and age-matched control eyes. Retinal wholemounts were stained for markers of retinal astrocytes and activated Müller cells (glial fibrillary acidic protein, GFAP), Müller cells (vimentin, glutamine synthetase) and microglia/hyalocytes (IBA-1). Retinal vessels were labeled with UEA lectin. Images were collected using a Zeiss 710 confocal microscope. Retinas were then cryopreserved. Laminin labeling of cryosections determined the location of glial structures in relation to the ILM. All retinas investigated herein had varied amounts of preretinal glial. These glial structures were classified into three groups based on size: sprouts, blooms, and membranes. The simplest of the glial structures observed were focal sprouts of singular GFAP-positive cells or processes on the vitreal surface of the ILM. The intermediate structures observed, glial blooms, were created by multiple cells/processes exiting from a single point and extending along the vitreoretinal surface. The most extensive structures, glial membranes, consisted of compact networks of cells and processes. Preretinal glia were observed in all areas of the retina but they were most prominent over large vessels. While all glial blooms and membranes contained vimentin and GFAP-positive cells, these proteins did not always co-localize. Many areas had no preretinal GFAP but had numerous vimentin only glial sprouts. In double labelled glial sprouts, vimentin staining extended beyond that of GFAP. Hyalocytes and microglia were detected along with glial sprouts, blooms, and membranes. They did not, however, concentrate in the retina below these structures. Cross sectional analysis identified small breaks in the ILM above large retinal vessels through which glial cells exited the retina. Preretinal glial structures of varied sizes are a common occurrence in aged retinas and, in most cases, are subclinical. While all retinal glia are found in blooms, vimentin labeling suggests that Müller cells form the leading edge. All retinas investigated from eyes with active choroidal neovascularization (CNV) had extensive glial membranes on the vitreal surface of the ILM. Although these structures may be benign, they may exert traction on the retina as they spread along the vitreoretinal interface. In cases with CNV, glial cells in the vitreous could bind intravitreally injected anti-vascular endothelial growth factor. These preretinal glial structures indicate the remodeling of both astrocytes and Müller cells in aged retinas, in particular those with advanced AMD. PMID:26220834

Short communication: Tryptic β-casein hydrolysate modulates enteric nervous system development in primary culture.

PubMed

Cossais, F; Clawin-Rädecker, I; Lorenzen, P C; Klempt, M

2017-05-01

The intestinal tract of the newborn is particularly sensitive to gastrointestinal disorders, such as infantile diarrhea or necrotizing colitis. Perinatal development of the gut also encompasses the maturation of the enteric nervous system (ENS), a main regulator of intestinal motility and barrier functions. It was recently shown that ENS maturation can be enhanced by nutritional factors to improve intestinal maturation. Bioactivity of milk proteins is often latent, requiring the release of bioactive peptides from inactive native proteins. Several casein-derived hydrolysates presenting immunomodulatory properties have been described recently. Furthermore, accumulating data indicate that milk-derived hydrolysate can enhance gut maturation and enrichment of milk formula with such hydrolysates has recently been proposed. However, the capability of milk-derived bioactive hydrolysate to target ENS maturation has not been analyzed so far. We, therefore, investigated the potential of a recently described tryptic β-casein hydrolysate to modulate ENS growth parameters in an in vitro model of rat primary culture of ENS. Rat primary cultures of ENS were incubated with a bioactive tryptic β-casein hydrolysate and compared with untreated controls or to cultures treated with native β-casein or a Prolyve β-casein hydrolysate (Lyven, Colombelles, France). Differentiation of enteric neurons and enteric glial cells, and establishment of enteric neural network were analyzed using immunohistochemistry and quantitative PCR. Effect of tryptic β-casein hydrolysate on bone morphogenetic proteins (BMP)/Smad pathway, an essential regulator of ENS development, was further assessed using quantitative PCR and immunochemistry. Tryptic β-casein hydrolysate stimulated neurite outgrowth and simultaneously modulated the formation of enteric ganglia-like structures, whereas native β-casein or Prolyve β-casein hydrolysate did not. Additionally, treatment with tryptic bioactive β-casein hydrolysate increased the expression of the glial marker glial fibrillary acidic protein and induced profound modifications of enteric glial cells morphology. Finally, expression of BMP2 and BMP4 and activation of Smad1/5 was altered after treatment with tryptic bioactive β-casein hydrolysate. Our data suggests that this milk-derived bioactive hydrolysate modulates ENS maturation through the regulation of BMP/Smad-signaling pathway. This study supports the need for further investigation on the influence of milk-derived bioactive peptides on ENS and intestinal maturation in vivo. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Localization of a GABA transporter to glial cells in the developing and adult olfactory pathway of the moth Manduca sexta1

PubMed Central

Oland, Lynne A; Gibson, Nicholas J; Tolbert, Leslie P

2010-01-01

Glial cells have several critical roles in the developing and adult olfactory (antennal) lobe of the moth Manduca sexta. Early in development, glial cells occupy discrete regions of the developing olfactory pathway and processes of GABAergic neurons extend into some of these regions. Because GABA is known to have developmental effects in a variety of systems, we explored the possibility that the glial cells express a GABA transporter that could regulate GABA levels to which olfactory neurons and glial cells are exposed. Using an antibody raised against a characterized high-affinity M. sexta GABA transporter with high sequence homology to known mammalian GABA transporters (Mbungu et al., 1995; Umesh and Gill, 2002), we found that the GABA transporter is localized to subsets of centrally derived glial cells during metamorphic adult development. The transporter persists into adulthood in a subset of the neuropil-associated glial cells, but its distribution pattern as determined by light- and electron-microscopic-level immunocytochemistry indicates that it could not serve to regulate GABA concentration in the synaptic cleft. Rather its role is more likely to regulate extracellular GABA levels within the glomerular neuropil. Expression in the sorting zone glial cells disappears after the period of olfactory receptor axon ingrowth, but may be important during ingrowth if GABA regulates axon growth. Glial cells take up GABA, and that uptake can be blocked by DABA. This is the first molecular evidence that the central glial cell population in this pathway is heterogeneous. PMID:20058309

Isolated dorsal root ganglion neurones inhibit receptor-dependent adenylyl cyclase activity in associated glial cells

PubMed Central

Ng, KY; Yeung, BHS; Wong, YH; Wise, H

2013-01-01

Background and Purpose Hyper-nociceptive PGE2 EP4 receptors and prostacyclin (IP) receptors are present in adult rat dorsal root ganglion (DRG) neurones and glial cells in culture. The present study has investigated the cell-specific expression of two other Gs-protein coupled hyper-nociceptive receptor systems: β-adrenoceptors and calcitonin gene-related peptide (CGRP) receptors in isolated DRG cells and has examined the influence of neurone–glial cell interactions in regulating adenylyl cyclase (AC) activity. Experimental Approach Agonist-stimulated AC activity was determined in mixed DRG cell cultures from adult rats and compared with activity in DRG neurone-enriched cell cultures and pure DRG glial cell cultures. Key Results Pharmacological analysis showed the presence of Gs-coupled β2-adrenoceptors and CGRP receptors, but not β1-adrenoceptors, in all three DRG cell preparations. Agonist-stimulated AC activity was weakest in DRG neurone-enriched cell cultures. DRG neurones inhibited IP receptor-stimulated glial cell AC activity by a process dependent on both cell–cell contact and neurone-derived soluble factors, but this is unlikely to involve purine or glutamine receptor activation. Conclusions and Implications Gs-coupled hyper-nociceptive receptors are readily expressed on DRG glial cells in isolated cell cultures and the activity of CGRP, EP4 and IP receptors, but not β2-adrenoceptors, in glial cells is inhibited by DRG neurones. Studies using isolated DRG cells should be aware that hyper-nociceptive ligands may stimulate receptors on glial cells in addition to neurones, and that variable numbers of neurones and glial cells will influence absolute measures of AC activity and affect downstream functional responses. PMID:22924655

The Drosophila blood-brain barrier: development and function of a glial endothelium.

PubMed

Limmer, Stefanie; Weiler, Astrid; Volkenhoff, Anne; Babatz, Felix; Klämbt, Christian

2014-01-01

The efficacy of neuronal function requires a well-balanced extracellular ion homeostasis and a steady supply with nutrients and metabolites. Therefore, all organisms equipped with a complex nervous system developed a so-called blood-brain barrier, protecting it from an uncontrolled entry of solutes, metabolites or pathogens. In higher vertebrates, this diffusion barrier is established by polarized endothelial cells that form extensive tight junctions, whereas in lower vertebrates and invertebrates the blood-brain barrier is exclusively formed by glial cells. Here, we review the development and function of the glial blood-brain barrier of Drosophila melanogaster. In the Drosophila nervous system, at least seven morphologically distinct glial cell classes can be distinguished. Two of these glial classes form the blood-brain barrier. Perineurial glial cells participate in nutrient uptake and establish a first diffusion barrier. The subperineurial glial (SPG) cells form septate junctions, which block paracellular diffusion and thus seal the nervous system from the hemolymph. We summarize the molecular basis of septate junction formation and address the different transport systems expressed by the blood-brain barrier forming glial cells.

Endogenous purinergic signaling is required for osmotic volume regulation of retinal glial cells.

PubMed

Wurm, Antje; Lipp, Stephan; Pannicke, Thomas; Linnertz, Regina; Krügel, Ute; Schulz, Angela; Färber, Katrin; Zahn, Dirk; Grosse, Johannes; Wiedemann, Peter; Chen, Ju; Schöneberg, Torsten; Illes, Peter; Reichenbach, Andreas; Bringmann, Andreas

2010-03-01

Intense neuronal activity in the sensory retina is associated with a volume increase of neuronal cells (Uckermann et al., J. Neurosci. 2004, 24:10149) and a decrease in the osmolarity of the extracellular space fluid (Dmitriev et al., Vis. Neurosci. 1999, 16:1157). Here, we show the existence of an endogenous purinergic mechanism that prevents hypoosmotic swelling of retinal glial (Müller) cells in mice. In contrast to the cells from wild-type mice, hypoosmotic stress induced rapid swelling of glial cell somata in retinal slices from mice deficient in P2Y(1), adenosine A(1) receptors, or ecto-5'-nucleotidase (CD73). Consistently, glial cell bodies in retinal slices from wild-type mice displayed osmotic swelling when P2Y(1) or A(1) receptors, or CD73, were pharmacologically blocked. Exogenous ATP, UTP, and UDP inhibited glial swelling in retinal slices, while the swelling of isolated glial cells was prevented by ATP but not by UTP or UDP, suggesting that uracil nucleotides indirectly regulate the glial cell volume via activation of neuronal P2Y(4/6) and neuron-to-glia signaling. It is suggested that autocrine/paracrine activation of purinergic receptors and enzymes is crucially involved in the regulation of the glial cell volume.

Oxytocin Modulates Expression of Neuron and Glial Markers in the Rat Hippocampus.

PubMed

Havránek, T; Lešťanová, Z; Mravec, B; Štrbák, V; Bakoš, J; Bačová, Z

2017-01-01

Neuropeptides including oxytocin belong to the group of factors that may play a role in the control of neuronal cell survival, proliferation and differentiation. The aim of the present study was to investigate potential contribution of oxytocin to neuronal differentiation by measuring gene and protein expression of specific neuron and glial markers in the brain. Neonatal and adult oxytocin administration was used to reveal developmental and/or acute effects of oxytocin in Wistar rats. Gene and protein expression of neuron-specific enolase (NSE) in the hippocampus was increased in 21-day and 2-month old rats in response to neonatal oxytocin administration. Neonatal oxytocin treatment induced a significant increase of gene and protein expression of the marker of astrocytes - glial fibrillary acid protein (GFAP). Oxytocin treatment resulted in a decrease of oligodendrocyte marker mRNA - 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) - in 21-day and 2-month old rats, while no change of CD68 mRNA, marker of microglia, was observed. Central oxytocin administration in adult rats induced a significant increase of gene expression of NSE and CNPase. The present study provides the first data revealing the effect of oxytocin on the expression of neuron and glial markers in the brain. It may be suggested that the oxytocin system is involved in the regulation of development of neuronal precursor cells in the brain.

Honeybee retinal glial cells transform glucose and supply the neurons with metabolic substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsacopoulos, M.; Evequoz-Mercier, V.; Perrottet, P.

1988-11-01

The retina of the honeybee drone is a nervous tissue in which glial cells and photoreceptor cells (sensory neurons) constitute two distinct metabolic compartments. Retinal slices incubated with 2-deoxy(/sup 3/H)glucose convert this glucose analogue to 2-deoxy(/sup 3/H)glucose 6-phosphate, but this conversion is made only in the glial cells. Hence, glycolysis occurs only in glial cells. In contrast, the neurons consume O/sub 2/ and this consumption is sustained by the hydrolysis of glycogen, which is contained in large amounts in the glia. During photostimulation the increased oxidative metabolism of the neurons is sustained by a higher supply of carbohydrates from themore » glia. This clear case of metabolic interaction between neurons and glial cells supports Golgi's original hypothesis, proposed nearly 100 years ago, about the nutritive function of glial cells in the nervous system.« less

Honeybee Retinal Glial Cells Transform Glucose and Supply the Neurons with Metabolic Substrate

NASA Astrophysics Data System (ADS)

Tsacopoulos, M.; Evequoz-Mercier, V.; Perrottet, P.; Buchner, E.

1988-11-01

The retina of the honeybee drone is a nervous tissue in which glial cells and photoreceptor cells (sensory neurons) constitute two distinct metabolic compartments. Retinal slices incubated with 2-deoxy[3H]glucose convert this glucose analogue to 2-deoxy[3H]glucose 6-phosphate, but this conversion is made only in the glial cells. Hence, glycolysis occurs only in glial cells. In contrast, the neurons consume O2 and this consumption is sustained by the hydrolysis of glycogen, which is contained in large amounts in the glia. During photostimulation the increased oxidative metabolism of the neurons is sustained by a higher supply of carbohydrates from the glia. This clear case of metabolic interaction between neurons and glial cells supports Golgi's original hypothesis, proposed nearly 100 years ago, about the nutritive function of glial cells in the nervous system.

Specialized Cortex Glial Cells Accumulate Lipid Droplets in Drosophila melanogaster.

PubMed

Kis, Viktor; Barti, Benjámin; Lippai, Mónika; Sass, Miklós

2015-01-01

Lipid droplets (LDs) are common organelles of the majority of eukaryotic cell types. Their biological significance has been extensively studied in mammalian liver cells and white adipose tissue. Although the central nervous system contains the highest relative amount and the largest number of different lipid species, neither the spatial nor the temporal distribution of LDs has been described. In this study, we used the brain of the fruitfly, Drosophila melanogaster, to investigate the neuroanatomy of LDs. We demonstrated that LDs are exclusively localised in glial cells but not in neurons in the larval nervous system. We showed that the brain's LD pool, rather than being constant, changes dynamically during development and reaches its highest value at the beginning of metamorphosis. LDs are particularly enriched in cortex glial cells located close to the brain surface. These specialized superficial cortex glial cells contain the highest amount of LDs among glial cell types and encapsulate neuroblasts and their daughter cells. Superficial cortex glial cells, combined with subperineurial glial cells, express the Drosophila fatty acid binding protein (Dfabp), as we have demonstrated through light- and electron microscopic immunocytochemistry. To the best of our best knowledge this is the first study that describes LD neuroanatomy in the Drosophila larval brain.

Activation of satellite glial cells in trigeminal ganglion following dental injury and inflammation.

PubMed

Liu, Haichao; Zhao, Lei; Gu, Wenzhen; Liu, Qin; Gao, Zhixiong; Zhu, Xiao; Wu, Zhi; He, Hongwen; Huang, Fang; Fan, Wenguo

2018-06-01

Satellite glial cells (SGCs), a peripheral neuroglial cell, surround neurons and form a complete envelope around individual sensory neurons in the trigeminal ganglia (TG), which may be involved in modulating neurons in inflammation. The purpose of this study was to determine the effect of dental injury and inflammation on SGCs in the TG. Pulp exposure (PX) was performed on the first maxillary molar of 28 rats. The neurons innervating injured tooth in TG were labeled by the retrograde transport of fluoro-gold (FG). Specimens were collected at 1, 3, 7, 14, 21 and 28 days after PX and stained immunohistochemically for glial fibrillary acid protein (GFAP), a marker of SGCs activation, in the TG. We observed that GFAP-immunoreactivity (IR) SGCs enclosed FG-labeled neurons increased in a time-dependent manner after PX. The neurons surrounded by GFAP-IR SGCs were mainly small and medium in size. The GFAP-IR SGCs encircled neurons increased significantly in the maxillary nerve region of the TG at 7-28 days following PX. The results show that dental injury and inflammation induced SGCs activation in the TG. It indicates that activation of SGCs might be implicated in the peripheral mechanisms of pain following dental injury and inflammation.

Tumour-associated glial host cells display a stem-like phenotype with a distinct gene expression profile and promote growth of GBM xenografts.

PubMed

Leiss, Lina; Mutlu, Ercan; Øyan, Anne; Yan, Tao; Tsinkalovsky, Oleg; Sleire, Linda; Petersen, Kjell; Rahman, Mohummad Aminur; Johannessen, Mireille; Mitra, Sidhartha S; Jacobsen, Hege K; Talasila, Krishna M; Miletic, Hrvoje; Jonassen, Inge; Li, Xingang; Brons, Nicolaas H; Kalland, Karl-Henning; Wang, Jian; Enger, Per Øyvind

2017-02-07

Little is known about the role of glial host cells in brain tumours. However, supporting stromal cells have been shown to foster tumour growth in other cancers. We isolated stromal cells from patient-derived glioblastoma (GBM) xenografts established in GFP-NOD/scid mice. With simultaneous removal of CD11b + immune and CD31 + endothelial cells by fluorescence activated cell sorting (FACS), we obtained a population of tumour-associated glial cells, TAGs, expressing markers of terminally differentiaed glial cell types or glial progenitors. This cell population was subsequently characterised using gene expression analyses and immunocytochemistry. Furthermore, sphere formation was assessed in vitro and their glioma growth-promoting ability was examined in vivo. Finally, the expression of TAG related markers was validated in human GBMs. TAGs were highly enriched for the expression of glial cell proteins including GFAP and myelin basic protein (MBP), and immature markers such as Nestin and O4. A fraction of TAGs displayed sphere formation in stem cell medium. Moreover, TAGs promoted brain tumour growth in vivo when co-implanted with glioma cells, compared to implanting only glioma cells, or glioma cells and unconditioned glial cells from mice without tumours. Genome-wide microarray analysis of TAGs showed an expression profile distinct from glial cells from healthy mice brains. Notably, TAGs upregulated genes associated with immature cell types and self-renewal, including Pou3f2 and Sox2. In addition, TAGs from highly angiogenic tumours showed upregulation of angiogenic factors, including Vegf and Angiopoietin 2. Immunohistochemistry of three GBMs, two patient biopsies and one GBM xenograft, confirmed that the expression of these genes was mainly confined to TAGs in the tumour bed. Furthermore, their expression profiles displayed a significant overlap with gene clusters defining prognostic subclasses of human GBMs. Our data demonstrate that glial host cells in brain tumours are functionally distinct from glial cells of healthy mice brains. Furthermore, TAGs display a gene expression profile with enrichment for genes related to stem cells, immature cell types and developmental processes. Future studies are needed to delineate the biological mechanisms regulating the brain tumour-host interplay.

Glutamate-mediated protection of crayfish glial cells from PDT-induced apoptosis

NASA Astrophysics Data System (ADS)

Rudkovskii, M. V.; Romanenko, N. P.; Berezhnaya, E. V.; Kovaleva, V. D.; Uzdensky, A. B.

2011-03-01

Photodynamic treatment that causes intense oxidative stress and kills cells is currently used in neurooncology. However, along with tumor it damages surrounding healthy neurons and glial cells. In order to study the possible role of glutamate-related signaling pathways in photodynamic injury of neurons and glia, we investigated photodynamic effect of alumophthalocyanine Photosens on isolated crayfish stretch receptor that consists of a single neuron surrounded by glial cells. The laser diode (670 nm, 0.4 W/cm2) was used for dye photoexcitation. Application of glutamate increased photodynamically induced necrosis of neurons and glial cells but significantly decreased glial apoptosis. The natural neuroglial mediator N-acetylaspartylglutamate, which releases glutamate after cleavage in the extracellular space by glutamate carboxypeptidase II, also inhibited photoinduced apoptosis. Inhibition of glutamate carboxypeptidase II, oppositely, enhanced apoptosis of glial cells. These data confirm the anti-apoptotic activity of glutamate. Application of NMDA or inhibition of NMDA receptors by MK801 did not influence photodynamic death of neurons and glial cells that indicated nonparticipation of NMDA receptors in these processes. Inhibition of metabotropic glutamate receptors by AP-3 decreased PDT-induced apoptosis. One can suggest that crayfish neurons naturally secrete NAAG, which being cleaved by GCOP produces glutamate. Glutamate prevents photoinduced apoptosis of glial cells possibly through metabotropic but not ionotropic glutamate receptors.

Macrophage-Mediated Glial Cell Elimination in the Postnatal Mouse Cochlea

PubMed Central

Brown, LaShardai N.; Xing, Yazhi; Noble, Kenyaria V.; Barth, Jeremy L.; Panganiban, Clarisse H.; Smythe, Nancy M.; Bridges, Mary C.; Zhu, Juhong; Lang, Hainan

2017-01-01

Hearing relies on the transmission of auditory information from sensory hair cells (HCs) to the brain through the auditory nerve. This relay of information requires HCs to be innervated by spiral ganglion neurons (SGNs) in an exclusive manner and SGNs to be ensheathed by myelinating and non-myelinating glial cells. In the developing auditory nerve, mistargeted SGN axons are retracted or pruned and excessive cells are cleared in a process referred to as nerve refinement. Whether auditory glial cells are eliminated during auditory nerve refinement is unknown. Using early postnatal mice of either sex, we show that glial cell numbers decrease after the first postnatal week, corresponding temporally with nerve refinement in the developing auditory nerve. Additionally, expression of immune-related genes was upregulated and macrophage numbers increase in a manner coinciding with the reduction of glial cell numbers. Transient depletion of macrophages during early auditory nerve development, using transgenic CD11bDTR/EGFP mice, resulted in the appearance of excessive glial cells. Macrophage depletion caused abnormalities in myelin formation and transient edema of the stria vascularis. Macrophage-depleted mice also showed auditory function impairment that partially recovered in adulthood. These findings demonstrate that macrophages contribute to the regulation of glial cell number during postnatal development of the cochlea and that glial cells play a critical role in hearing onset and auditory nerve maturation. PMID:29375297

Modulation of Brain Hemichannels and Gap Junction Channels by Pro-Inflammatory Agents and Their Possible Role in Neurodegeneration

PubMed Central

Sáez, Pablo J.; Shoji, Kenji F.; Schalper, Kurt A.; Palacios–Prado, Nicolás; Velarde, Victoria; Giaume, Christian; Bennett, Michael V.L.; Sáez, Juan C.

2009-01-01

Abstract In normal brain, neurons, astrocytes, and oligodendrocytes, the most abundant and active cells express pannexins and connexins, protein subunits of two families forming membrane channels. Most available evidence indicates that in mammals endogenously expressed pannexins form only hemichannels and connexins form both gap junction channels and hemichannels. Whereas gap junction channels connect the cytoplasm of contacting cells and coordinate electric and metabolic activity, hemichannels communicate the intra- and extracellular compartments and serve as a diffusional pathway for ions and small molecules. A subthreshold stimulation by acute pathological threatening conditions (e.g., global ischemia subthreshold for cell death) enhances neuronal Cx36 and glial Cx43 hemichannel activity, favoring ATP release and generation of preconditioning. If the stimulus is sufficiently deleterious, microglia become overactivated and release bioactive molecules that increase the activity of hemichannels and reduce gap junctional communication in astroglial networks, depriving neurons of astrocytic protective functions, and further reducing neuronal viability. Continuous glial activation triggered by low levels of anomalous proteins expressed in several neurodegenerative diseases induce glial hemichannel and gap junction channel disorders similar to those of acute inflammatory responses triggered by ischemia or infectious diseases. These changes are likely to occur in diverse cell types of the CNS and contribute to neurodegeneration during inflammatory process. Antiox. Redox Signal. 11, 369–399. PMID:18816186

Exposure of cultured astroglial and microglial brain cells to 900 MHz microwave radiation.

PubMed

Thorlin, Thorleif; Rouquette, Jean-Michel; Hamnerius, Yngve; Hansson, Elisabeth; Persson, Mikael; Björklund, Ulrika; Rosengren, Lars; Rönnbäck, Lars; Persson, Mikael

2006-08-01

The rapid rise in the use of mobile communications has raised concerns about health issues related to low-level microwave radiation. The head and brain are usually the most exposed targets in mobile phone users. In the brain, two types of glial cells, the astroglial and the microglial cells, are interesting in the context of biological effects from microwave exposure. These cells are widely distributed in the brain and are directly involved in the response to brain damage as well as in the development of brain cancer. The aim of the present study was to investigate whether 900 MHz radiation could affect these two different glial cell types in culture by studying markers for damage-related processes in the cells. Primary cultures enriched in astroglial cells were exposed to 900 MHz microwave radiation in a temperature-controlled exposure system at specific absorption rates (SARs) of 3 W/kg GSM modulated wave (mw) for 4, 8 and 24 h or 27 W/kg continuous wave (cw) for 24 h, and the release into the extracellular medium of the two pro-inflammatory cytokines interleukin 6 (Il6) and tumor necrosis factor-alpha (Tnfa) was analyzed. In addition, levels of the astroglial cell-specific reactive marker glial fibrillary acidic protein (Gfap), whose expression dynamics is different from that of cytokines, were measured in astroglial cultures and in astroglial cell-conditioned cell culture medium at SARs of 27 and 54 W/kg (cw) for 4 or 24 h. No significant differences could be detected for any of the parameters studied at any time and for any of the radiation characteristics. Total protein levels remained constant during the experiments. Microglial cell cultures were exposed to 900 MHz radiation at an SAR of 3 W/kg (mw) for 8 h, and I16, Tnfa, total protein and the microglial reactivity marker ED-1 (a macrophage activation antigen) were measured. No significant differences were found. The morphology of the cultured astroglial cells and microglia was studied and appeared to be unaffected by microwave irradiation. Thus this study does not provide evidence for any effect of the microwave radiation used on damage-related factors in glial cells in culture.

Astrocyte–endothelial interactions and blood–brain barrier permeability*

PubMed Central

Abbott, N Joan

2002-01-01

The blood–brain barrier (BBB) is formed by brain endothelial cells lining the cerebral microvasculature, and is an important mechanism for protecting the brain from fluctuations in plasma composition, and from circulating agents such as neurotransmitters and xenobiotics capable of disturbing neural function. The barrier also plays an important role in the homeostatic regulation of the brain microenvironment necessary for the stable and co-ordinated activity of neurones. The BBB phenotype develops under the influence of associated brain cells, especially astrocytic glia, and consists of more complex tight junctions than in other capillary endothelia, and a number of specific transport and enzyme systems which regulate molecular traffic across the endothelial cells. Transporters characteristic of the BBB phenotype include both uptake mechanisms (e.g. GLUT-1 glucose carrier, L1 amino acid transporter) and efflux transporters (e.g. P-glycoprotein). In addition to a role in long-term barrier induction and maintenance, astrocytes and other cells can release chemical factors that modulate endothelial permeability over a time-scale of seconds to minutes. Cell culture models, both primary and cell lines, have been used to investigate aspects of barrier induction and modulation. Conditioned medium taken from growing glial cells can reproduce some of the inductive effects, evidence for involvement of diffusible factors. However, for some features of endothelial differentiation and induction, the extracellular matrix plays an important role. Several candidate molecules have been identified, capable of mimicking aspects of glial-mediated barrier induction of brain endothelium; these include TGFβ, GDNF, bFGF, IL-6 and steroids. In addition, factors secreted by brain endothelial cells including leukaemia inhibitory factor (LIF) have been shown to induce astrocytic differentiation. Thus endothelium and astrocytes are involved in two-way induction. Short-term modulation of brain endothelial permeability has been shown for a number of small chemical mediators produced by astrocytes and other nearby cell types. It is clear that endothelial cells are involved in both long- and short-term chemical communication with neighbouring cells, with the perivascular end feet of astrocytes being of particular importance. The role of barrier induction and modulation in normal physiology and in pathology is discussed. PMID:12162730

At the Origin of the History of Glia.

PubMed

Fan, Xue; Agid, Yves

2018-06-08

The history of brain science is dominated by the study of neurons. However, there are as many glial cells as neurons in the human brain, their complexity increases during evolution, and glial cells play important roles in brain function, behavior, and neurological disorders. Although neurons and glial cells were first described at the same time in the early 19th century, why did the physiological study of glial cells only begin in the 1950s? What are the scientific breakthroughs and conceptual shifts that determined the history of glial cells in relation to that of neurons? What is the impact of the history of glia on the evolution of neuroscience? In order to answer these questions, we reconstructed the history of glial cells, from their first description until the mid-20th century, by examining the relative role of technical developments and scientific interpretations. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Photodynamic therapy-induced nitric oxide production in neuronal and glial cells

NASA Astrophysics Data System (ADS)

Kovaleva, Vera D.; Uzdensky, Anatoly B.

2016-10-01

Nitric oxide (NO) has been recently demonstrated to enhance apoptosis of glial cells induced by photodynamic therapy (PDT), but to protect glial cells from PDT-induced necrosis in the crayfish stretch receptor, a simple neuroglial preparation that consists of a single mechanosensory neuron enveloped by satellite glial cells. We used the NO-sensitive fluorescent probe 4,5-diaminofluorescein diacetate to study the distribution and dynamics of PDT-induced NO production in the mechanosensory neuron and surrounding glial cells. The NO production in the glial envelope was higher than in the neuronal soma axon and dendrites both in control and in experimental conditions. In dark NO generator, DEA NONOate or NO synthase substrate L-arginine hydrochloride significantly increased the NO level in glial cells, whereas NO scavenger 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) or inhibitors of NO synthase L-NG-nitro arginine methyl ester and Nω-nitro-L-arginine decreased it. PDT induced the transient increase in NO production with a maximum at 4 to 7 min after the irradiation start followed by its inhibition at 10 to 40 min. We suggested that PDT stimulated neuronal rather than inducible NO synthase isoform in glial cells, and the produced NO could mediate PDT-induced apoptosis.

Induction of neuronal phenotypes from NG2+ glial progenitors by inhibiting epidermal growth factor receptor in mouse spinal cord injury.

PubMed

Ju, Peijun; Zhang, Si; Yeap, Yeeshan; Feng, Zhiwei

2012-11-01

Besides neural stem cells, some glial cells, such as GFAP+ cells, radial glia, and oligodendrocyte progenitor cells can produce neuronal cells. Attractively, NG2+ glial progenitors exhibit lineage plasticity, and they rapidly proliferate and differentiate in response to central nervous system (CNS) injuries. These attributes of NG2+ glial progenitors make them a promising source of neurons. However, the potential of neuronal regeneration from NG2+ glial progenitors in CNS pathologies remains to be investigated. In this study, we showed that antagonizing epidermal growth factor receptor (EGFR) function with EGFR inhibitor caused a significant number of proliferative NG2+ glial progenitors to acquire neuronal phenotypes in contusive spinal cord injury (SCI), which presumably led to an accumulation of newly generated neurons and contributed to the improved neural behavioral performance of animals. In addition, the neuronal differentiation of glial progenitors induced by EGFR inhibitor was further confirmed with two different cell lines either in vitro or through ex vivo transplantation experiment. The inhibition of EGFR signaling pathway under the gliogenic conditions could induce these cells to acquire neuronal phenotypes. Furthermore, we find that the Ras-ERK axis played a key role in neuronal differentiation of NG2+ glial progenitors upon EGFR inhibition. Taken together, our studies suggest that the EGFR inhibitor could promote neurogenesis post SCI, mainly from the NG2+ glial progenitors. These findings support the possibility of evoking endogenous neuronal replacement from NG2+ glial progenitors and suggest that EGFR inhibition may be beneficial to CNS trauma. Copyright © 2012 Wiley Periodicals, Inc.

TDP-43 causes differential pathology in neuronal versus glial cells in the mouse brain

PubMed Central

Yan, Sen; Wang, Chuan-En; Wei, Wenjie; Gaertig, Marta A.; Lai, Liangxue; Li, Shihua; Li, Xiao-Jiang

2014-01-01

Mutations in TAR DNA-binding protein 43 (TDP-43) are associated with familial forms of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Although recent studies have revealed that mutant TDP-43 in neuronal and glial cells is toxic, how mutant TDP-43 causes primarily neuronal degeneration in an age-dependent manner remains unclear. Using adeno-associated virus (AAV) that expresses mutant TDP-43 (M337V) ubiquitously, we found that mutant TDP-43 accumulates preferentially in neuronal cells in the postnatal mouse brain. We then ubiquitously or selectively expressed mutant TDP-43 in neuronal and glial cells in the striatum of adult mouse brains via stereotaxic injection of AAV vectors and found that it also preferentially accumulates in neuronal cells. Expression of mutant TDP-43 in neurons in the striatum causes more severe degeneration, earlier death and more robust symptoms in mice than expression of mutant TDP-43 in glial cells; however, aging increases the expression of mutant TDP-43 in glial cells, and expression of mutant TDP-43 in older mice caused earlier onset of phenotypes and more severe neuropathology than that in younger mice. Although expression of mutant TDP-43 in glial cells via stereotaxic injection does not lead to robust neurological phenotypes, systemic inhibition of the proteasome activity via MG132 in postnatal mice could exacerbate glial TDP-43-mediated toxicity and cause mice to die earlier. Consistently, this inhibition increases the expression of mutant TDP-43 in glial cells in mouse brains. Thus, the differential accumulation of mutant TDP-43 in neuronal versus glial cells contributes to the preferential toxicity of mutant TDP-43 in neuronal cells and age-dependent pathology. PMID:24381309

TDP-43 causes differential pathology in neuronal versus glial cells in the mouse brain.

PubMed

Yan, Sen; Wang, Chuan-En; Wei, Wenjie; Gaertig, Marta A; Lai, Liangxue; Li, Shihua; Li, Xiao-Jiang

2014-05-15

Mutations in TAR DNA-binding protein 43 (TDP-43) are associated with familial forms of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Although recent studies have revealed that mutant TDP-43 in neuronal and glial cells is toxic, how mutant TDP-43 causes primarily neuronal degeneration in an age-dependent manner remains unclear. Using adeno-associated virus (AAV) that expresses mutant TDP-43 (M337V) ubiquitously, we found that mutant TDP-43 accumulates preferentially in neuronal cells in the postnatal mouse brain. We then ubiquitously or selectively expressed mutant TDP-43 in neuronal and glial cells in the striatum of adult mouse brains via stereotaxic injection of AAV vectors and found that it also preferentially accumulates in neuronal cells. Expression of mutant TDP-43 in neurons in the striatum causes more severe degeneration, earlier death and more robust symptoms in mice than expression of mutant TDP-43 in glial cells; however, aging increases the expression of mutant TDP-43 in glial cells, and expression of mutant TDP-43 in older mice caused earlier onset of phenotypes and more severe neuropathology than that in younger mice. Although expression of mutant TDP-43 in glial cells via stereotaxic injection does not lead to robust neurological phenotypes, systemic inhibition of the proteasome activity via MG132 in postnatal mice could exacerbate glial TDP-43-mediated toxicity and cause mice to die earlier. Consistently, this inhibition increases the expression of mutant TDP-43 in glial cells in mouse brains. Thus, the differential accumulation of mutant TDP-43 in neuronal versus glial cells contributes to the preferential toxicity of mutant TDP-43 in neuronal cells and age-dependent pathology.

Activation of the P2X₇ receptor induces migration of glial cells by inducing cathepsin B degradation of tissue inhibitor of metalloproteinase 1.

PubMed

Murphy, Niamh; Lynch, Marina A

2012-12-01

The P2X(7) receptor is an ion-gated channel, which is activated by high extracellular concentrations of adenosine triphosphate (ATP). Activation of P2X(7) receptors has been shown to induce neuroinflammatory changes associated with several neurological conditions. The matrix metalloproteinases (MMPs) are a family of endopeptidases that have several functions including degradation of the extracellular matrix, cell migration and modulation of bioactive molecules. The actions of MMPs are prevented by a family of protease inhibitors called tissue inhibitors of metalloproteinases (TIMPs). In this study, we show that ATP-treated glial cultures from neonatal C57BL/6 mice release and increase MMP-9 activity, which is coupled with a decrease in release of TIMP-1 and an increase in activated cathepsin B within the extracellular space. This process occurs independently of NLRP3-inflammasome formation. Treatment with a P2X(7) receptor antagonist prevents ATP-induced MMP-9 activity, inhibition of active cathepsin B release and allows for TIMP-1 to be released from the cell. We have shown that cathepsin B degrades TIMP-1, and inhibition of cathepsin B allows for release of TIMP-1 and inhibits MMP-9 activity. We also present data that indicate that ATP or cell damage induces glial cell migration, which is inhibited by P2X(7) antagonism, depletion of MMP-9 or inhibition of cathepsin B. © 2012 International Society for Neurochemistry.

The glial cell line-derived neurotrophic factor (GDNF) does not acutely change acetylcholine release in developing and adult neuromuscular junction.

PubMed

Garcia, Neus; Santafé, Manel M; Tomàs, Marta; Lanuza, Maria A; Besalduch, Nuria; Priego, Merche; Tomàs, Josep

2010-08-16

We use immunocytochemistry to show that the trophic molecule glial cell line-derived neurotrophic factor (GDNF) and its receptor GDNF family receptor alpha-1 (GFRalpha-1) are present in both neonatal (P6) and adult (P45) rodent neuromuscular junctions (NMJ) colocalized with several synaptic markers. However, incubation with exogenous GDNF (10-200ng/ml, 1-3h), does not affect spontaneous ACh release. Moreover, GDNF does not change the size of the evoked ACh release from the weak and the strong axonal inputs on dually innervated postnatal endplates nor in the most developed singly-innervated synapses at P6 and P45. Our findings indicate that GDNF (unlike neurotrophins) does not acutely modulate transmitter release during the developmental process of synapse elimination nor as the NMJ matures. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

ATM kinase inhibition in glial cells activates the innate immune response and causes neurodegeneration in Drosophila.

PubMed

Petersen, Andrew J; Rimkus, Stacey A; Wassarman, David A

2012-03-13

To investigate the mechanistic basis for central nervous system (CNS) neurodegeneration in the disease ataxia-telangiectasia (A-T), we analyzed flies mutant for the causative gene A-T mutated (ATM). ATM encodes a protein kinase that functions to monitor the genomic integrity of cells and control cell cycle, DNA repair, and apoptosis programs. Mutation of the C-terminal amino acid in Drosophila ATM inhibited the kinase activity and caused neuron and glial cell death in the adult brain and a reduction in mobility and longevity. These data indicate that reduced ATM kinase activity is sufficient to cause neurodegeneration in A-T. ATM kinase mutant flies also had elevated expression of innate immune response genes in glial cells. ATM knockdown in glial cells, but not neurons, was sufficient to cause neuron and glial cell death, a reduction in mobility and longevity, and elevated expression of innate immune response genes in glial cells, indicating that a non-cell-autonomous mechanism contributes to neurodegeneration in A-T. Taken together, these data suggest that early-onset CNS neurodegeneration in A-T is similar to late-onset CNS neurodegeneration in diseases such as Alzheimer's in which uncontrolled inflammatory response mediated by glial cells drives neurodegeneration.

Glial activation in the collagenase model of nociception associated with osteoarthritis.

PubMed

Adães, Sara; Almeida, Lígia; Potes, Catarina S; Ferreira, Ana Rita; Castro-Lopes, José M; Ferreira-Gomes, Joana; Neto, Fani L

2017-01-01

Background Experimental osteoarthritis entails neuropathic-like changes in dorsal root ganglia (DRG) neurons. Since glial activation has emerged as a key player in nociception, being reported in numerous models of neuropathic pain, we aimed at evaluating if glial cell activation may also occur in the DRG and spinal cord of rats with osteoarthritis induced by intra-articular injection of collagenase. Methods Osteoarthritis was induced by two injections, separated by three days, of 500 U of type II collagenase into the knee joint of rats. Movement-induced nociception was evaluated by the Knee-Bend and CatWalk tests during the following six weeks. Glial fibrillary acidic protein (GFAP) expression in satellite glial cells of the DRG was assessed by immunofluorescence and Western Blot analysis; the pattern of GFAP and activating transcription factor-3 (ATF-3) expression was also compared through double immunofluorescence analysis. GFAP expression in astrocytes and IBA-1 expression in microglia of the L3-L5 spinal cord segments was assessed by immunohistochemistry and Western Blot analysis. The effect of the intrathecal administration of fluorocitrate, an inhibitor of glial activation, on movement-induced nociception was evaluated six weeks after the first collagenase injection. Results GFAP expression in satellite glial cells of collagenase-injected animals was significantly increased six weeks after osteoarthritis induction. Double immunofluorescence showed GFAP upregulation in satellite glial cells surrounding ATF-3-positive neurons. In the spinal cord of collagenase-injected animals, an ipsilateral upregulation of GFAP and IBA-1 was also observed. The inhibition of glial activation with fluorocitrate decreased movement- and loading-induced nociception. Conclusion Collagenase-induced knee osteoarthritis leads to the development of nociception associated with movement of the affected joint and to the activation of glial cells in both the DRG and the spinal cord. Inhibition of glial cell activation by fluorocitrate decreases these osteoarthritis-associated nociceptive behaviours. These results suggest that glial cell activation may play a role in the development of chronic pain in this experimental model of osteoarthritis.

Resveratrol Prevents Ammonia Toxicity in Astroglial Cells

PubMed Central

Guerra, Maria Cristina; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Gottfried, Carmem

2012-01-01

Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity. PMID:23284918

Modulation of neuroinflammation: Role and therapeutic potential of TRPV1 in the neuro-immune axis.

PubMed

Kong, Wei-Lin; Peng, Yuan-Yuan; Peng, Bi-Wen

2017-08-01

Transient receptor potential vanilloid type 1 channel (TRPV1), as a ligand-gated non-selective cation channel, has recently been demonstrated to have wide expression in the neuro-immune axis, where its multiple functions occur through regulation of both neuronal and non-neuronal activities. Growing evidence has suggested that TRPV1 is functionally expressed in glial cells, especially in the microglia and astrocytes. Glial cells perform immunological functions in response to pathophysiological challenges through pro-inflammatory or anti-inflammatory cytokines and chemokines in which TRPV1 is involved. Sustaining inflammation might mediate a positive feedback loop of neuroinflammation and exacerbate neurological disorders. Accumulating evidence has suggested that TRPV1 is closely related to immune responses and might be recognized as a molecular switch in the neuroinflammation of a majority of seizures and neurodegenerative diseases. In this review, we evidenced that inflammation modulates the expression and activity of TRPV1 in the central nervous system (CNS) and TRPV1 exerts reciprocal actions over neuroinflammatory processes. Together, the literature supports the hypothesis that TRPV1 may represent potential therapeutic targets in the neuro-immune axis. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of oxidative stress on hyperglycaemia-induced brain malformations in a diabetes mouse model.

PubMed

Jin, Ya; Wang, Guang; Han, Sha-Sha; He, Mei-Yao; Cheng, Xin; Ma, Zheng-Lai; Wu, Xia; Yang, Xuesong; Liu, Guo-Sheng

2016-09-10

Pregestational diabetes mellitus (PGDM) enhances the risk of fetal neurodevelopmental defects. However, the mechanism of hyperglycaemia-induced neurodevelopmental defects is not fully understood. In this study, several typical neurodevelopmental defects were identified in the streptozotocin-induced diabetes mouse model. The neuron-specific class III beta-tubulin/forkhead box P1-labelled neuronal differentiation was suppressed and glial fibrillary acidic protein-labelled glial cell lineage differentiation was slightly promoted in pregestational diabetes mellitus (PGDM) mice. Various concentrations of glucose did not change the U87 cell viability, but glial cell line-derived neurotrophic factor expression was altered with varying glucose concentrations. Mouse maternal hyperglycaemia significantly increased Tunel(+) apoptosis but did not dramatically affect PCNA(+) cell proliferation in the process. To determine the cause of increased apoptosis, we determined the SOD activity, the expression of Nrf2 as well as its downstream anti-oxidative factors NQO1 and HO1, and found that all of them significantly increased in PGDM fetal brains compared with controls. However, Nrf2 expression in U87 cells was not significantly changed by different glucose concentrations. In mouse telencephalon, we observed the co-localization of Tuj-1 and Nrf2 expression in neurons, and down-regulating of Nrf2 in SH-SY5Y cells altered the viability of SH-SY5Y cells exposed to high glucose concentrations. Taken together, the data suggest that Nrf2-modulated antioxidant stress plays a crucial role in maternal hyperglycaemia-induced neurodevelopmental defects. Copyright © 2016 Elsevier Inc. All rights reserved.

D-serine signalling as a prominent determinant of neuronal-glial dialogue in the healthy and diseased brain.

PubMed

Billard, J-M

2008-10-01

Rather different from their initial image as passive supportive cells of the CNS, the astrocytes are now considered as active partners at synapses, able to release a set of gliotransmitter-like substances to modulate synaptic communication within neuronal networks. Whereas glutamate and ATP were first regarded as main determinants of gliotransmission, growing evidence indicates now that the amino acid D-serine is another important player in the neuronal-glial dialogue. Through the regulation of glutamatergic neurotransmission through both N-methyl-D-aspartate (NMDA-R) and non-NMDA-R, D-serine is helping in modelling the appropriate connections in the developing brain and influencing the functional plasticity within neuronal networks throughout lifespan. The understanding of D-serine signalling, which has increased linearly in the last few years, gives new insights into the critical role of impaired neuronal-glial communication in the diseased brain, and offers new opportunities for developing relevant strategies to treat cognitive deficits associated to brain disorders.

D-serine signalling as a prominent determinant of neuronal-glial dialogue in the healthy and diseased brain

PubMed Central

Billard, J-M

2008-01-01

Rather different from their initial image as passive supportive cells of the CNS, the astrocytes are now considered as active partners at synapses, able to release a set of gliotransmitter-like substances to modulate synaptic communication within neuronal networks. Whereas glutamate and ATP were first regarded as main determinants of gliotransmission, growing evidence indicates now that the amino acid D-serine is another important player in the neuronal-glial dialogue. Through the regulation of glutamatergic neurotransmission through both N-methyl-D-aspartate (NMDA-R) and non-NMDA-R, D-serine is helping in modelling the appropriate connections in the developing brain and influencing the functional plasticity within neuronal networks throughout lifespan. The understanding of D-serine signalling, which has increased linearly in the last few years, gives new insights into the critical role of impaired neuronal-glial communication in the diseased brain, and offers new opportunities for developing relevant strategies to treat cognitive deficits associated to brain disorders. PMID:18363840

Trimethyltin-activated cyclooxygenase stimulates tumor necrosis factor-alpha release from glial cells through reactive oxygen species.

PubMed

Viviani, B; Corsini, E; Pesenti, M; Galli, C L; Marinovich, M

2001-04-15

Exposure of a primary culture of glial cells to the classical neurotoxicant trimethyltin (TMT) results in the release of prostaglandin (PG)E(2) and tumor necrosis factor (TNF)-alpha. Prior treatment of glial cells with either the nonspecific inhibitor of cyclooxygenase and lypoxygenase eicosatetraynoic acid (ETYA) or the cyclooxygenase inhibitor indomethacin completely prevented TMT-induced PGE(2) production and TNF-alpha release, suggesting a role for cyclooxygenase metabolites in TMT-induced TNF-alpha release. Exposure of glial cells to increasing concentrations of PGE(2) or other prostanoids did not increase TNF-alpha synthesis, while the presence of exogenous PGE(2) during treatment of glial cells with TMT actually suppressed TNF-alpha release. The activation of arachidonic acid metabolism produces reactive oxygen species (ROS). Scavenging of ROS by means of the antioxidant trolox prevented the TMT-induced release of TNF-alpha from glial cells, while indomethacin was found to suppress ROS formation induced by 1 microM TMT in glial cells. These results suggest that activation of arachidonic acid metabolism causes TNF-alpha release through the production of ROS rather than PGE(2). Indeed, PGE(2) may exert negative feedback on the release of TNF-alpha. Copyright 2001 Academic Press.

Glial cell biology in the Great Lakes region.

PubMed

Feinstein, Douglas L; Skoff, Robert P

2016-03-31

We report on the tenth bi-annual Great Lakes Glial meeting, held in Traverse City, Michigan, USA, September 27-29 2015. The GLG meeting is a small conference that focuses on current research in glial cell biology. The array of functions that glial cells (astrocytes, microglia, oligodendrocytes, Schwann cells) play in health and disease is constantly increasing. Despite this diversity, GLG meetings bring together scientists with common interests, leading to a better understanding of these cells. This year's meeting included two keynote speakers who presented talks on the regulation of CNS myelination and the consequences of stress on Schwann cell biology. Twenty-two other talks were presented along with two poster sessions. Sessions covered recent findings in the areas of microglial and astrocyte activation; age-dependent changes to glial cells, Schwann cell development and pathology, and the role of stem cells in glioma and neural regeneration.

Nonyloxytryptamine Mimics Polysialic Acid and Modulates Neuronal and Glial Functions in Cell Culture

DTIC Science & Technology

2014-01-01

polysialic acid (PSA) and 5-nonyloxytryptamine oxalate (5- NOT). (a) Shape and chemistry of PSA, shown as a surface, superimposed with the 3D structure of...process formation of Schwann cells (c) was determined in the presence and absence of colominic acid (CA), 5-nonyloxytryptamine oxalate (5-NOT) and 5-HT1B... oxalate (5-NOT) competes with colominic acid for binding to the PSA-specific antibody 735 (mAb 735). Figure S2. Representative images of (a) cerebellar

The LHRH-astroglial network of signals as a model to study neuroimmune interactions: assessment of messenger systems and transduction mechanisms at cellular and molecular levels.

PubMed

Marchetti, B

1996-01-01

Neurons and astrocytes have a close anatomic and functional relationship that plays a crucial role during development and in the adult brain. Astrocytes in the central nervous system (CNS) express receptors for a variety of growth factors (GFs), neurotransmitters and/or neuromodulators; in turn, neuronal cells can respond to astrocyte-derived GFs and control astrocyte function via a common set of signaling molecules and intracellular transducing pathways. There is also increasing evidence that soluble factors from lymphoid/mononuclear cells are able to modulate the growth and function of cells found in the CNS, specifically macroglial and microglial cells. Furthermore, glial cells can secrete immunoregulatory molecules that influence immune cells as well as the glial cells themselves. As neuronal and immune cells share common signaling systems, the potential exists for bidirectional communication not only between lymphoid and glial cells, but also between neuronal cells and immune and glial cells. In the present work, interactions of luteinizing-hormone-releasing hormone (LHRH) and the astroglial cell are proposed as a prototype for the study of neuroimmune communication within the CNS in the light of (1) the commonality of signal molecules (hormones, neurotransmitters and cytokines) and transduction mechanisms shared by glia LHRH neurons and lymphoid cells; (2) the central role of glia in the developmental organization and pattern of LHRH neuronal migration during embryogenesis, and (3) the strong modulatory role played by sex steroids in mechanisms involved in synaptic and interneuronal organization, as well as in the sexual dimorphisms of neuroendocrine-immune functions. During their maturation and differentiation in vitro, astroglial cells release factors able to accelerate markedly the LHRH neuronal phenotypic differentiation as well as the acquisition of mature LHRH secretory potential, with a potency depending on both the 'age' and the specific brain localization of the astroglia, as well as the degree of LHRH neuronal differentiation in vitro. Regional differences in astroglial sensitivity to estrogens were also measured. Different experimental paradigms such as coculture and mixed-culture models between the immortalized LHRH (GT1-1) neuronal cell line and astroglial cells in primary culture, disclosed the presence of a bidirectional flow of informational molecules regulating both proliferative and secretory capacities of each cell type. The importance of adhesive mechanisms in such cross-talk is underscored by the complete abolition of GT1-1 LHRH production and cell proliferation following the counteraction of neuronal-neuronal/neuronal-glial interactions through addition of neural-cell adhesion molecule antiserum. Other information came from pharmacological experiments manipulating the astroglia-derived cytokines and/or nitric oxide, which revealed cross-talk between the neuronal and astroglial compartments. From the bulk of this information, it seems likely that interactions between astroglia and LHRH neurons play a major role in the integration of the multiplicity of brain signals converging on the LHRH neurons that govern reproduction. Another important facet of neuronal-glial interactions is that concerning neuron-guided migration, and unraveling astroglial/LHRH-neuronal networks might then constitute an additional effort in the comprehension of defective LHRH-neuronal migration in Kallman's syndrome.

G5G2.5 core-shell tecto-dendrimer specifically targets reactive glia in brain ischemia.

PubMed

Murta, Veronica; Schilrreff, Priscila; Rosciszewski, Gerardo; Morilla, Maria Jose; Ramos, Alberto Javier

2018-03-01

Secondary neuronal death is a serious stroke complication. This process is facilitated by the conversion of glial cells to the reactive pro-inflammatory phenotype that induces neurodegeneration. Therefore, regulation of glial activation is a compelling strategy to reduce brain damage after stroke. However, drugs have difficulties to access the CNS, and to specifically target glial cells. In the present work, we explored the use core-shell polyamidoamine tecto-dendrimer (G5G2.5 PAMAM) and studied its ability to target distinct populations of stroke-activated glial cells. We found that G5G2.5 tecto-dendrimer is actively engulfed by primary glial cells in a time- and dose-dependent manner showing high cellular selectivity and lysosomal localization. In addition, oxygen-glucose deprivation or lipopolysaccharides exposure in vitro and brain ischemia in vivo increase glial G5G2.5 uptake; not being incorporated by neurons or other cell types. We conclude that G5G2.5 tecto-dendrimer is a highly suitable carrier for targeted drug delivery to reactive glial cells in vitro and in vivo after brain ischemia. © 2017 International Society for Neurochemistry.

On the role of adenylate cyclase, tyrosine kinase, and tyrosine phosphatase in the response of nerve and glial cells to photodynamic impact

NASA Astrophysics Data System (ADS)

Kolosov, Mikhail S.; Bragin, D. E.; Dergacheva, Olga Y.; Vanzha, O.; Oparina, L.; Uzdensky, Anatoly B.

2004-08-01

The role of different intercellular signaling pathways involving adenylate cyclase (AC), receptor tyrosine kinase (RTK), tyrosine and serine/threonine protein phosphatases (PTP or PP, respectively) in the response of crayfish mechanoreceptor neuron (MRN) and surrounding glial cells to photodynamic effect of aluminum phthalocyanine Photosens have been studied. AC inhibition by MDL-12330A decreased neuron lifetime, whereas AC activation by forskolin increase it. Thus, increase in cAMP produced by activated AC protects SRN against photodynamic inactivation. Similarly, RTK inhibition by genistein decreased neuron lifetime, while inhibition of PTP or PP that remove phosphate groups from proteins, prolonged neuronal activity. AC inhibition reduced photoinduced damage of the plasma membrane, and, therefore, necrosis in neuronal and glial cells. RTK inhibition protected only neurons against PDT-induced membrane permeabilization while glial cells became lesser permeable under ortovanadate-mediated PTP inhibition. AC activation also prevented PDT-induced apoptosis in glial cells. PP inhibition enhanced apoptotic processes in photosensitized glial cells. Therefore, both intercellular signaling pathways involving AC and TRK are involved in the maintenance of neuronal activity, integrity of the neuronal and glial plasma membranes and in apoptotic processes in glia under photosensitization.

The glia doctrine: addressing the role of glial cells in healthy brain ageing.

PubMed

Nagelhus, Erlend A; Amiry-Moghaddam, Mahmood; Bergersen, Linda H; Bjaalie, Jan G; Eriksson, Jens; Gundersen, Vidar; Leergaard, Trygve B; Morth, J Preben; Storm-Mathisen, Jon; Torp, Reidun; Walhovd, Kristine B; Tønjum, Tone

2013-10-01

Glial cells in their plurality pervade the human brain and impact on brain structure and function. A principal component of the emerging glial doctrine is the hypothesis that astrocytes, the most abundant type of glial cells, trigger major molecular processes leading to brain ageing. Astrocyte biology has been examined using molecular, biochemical and structural methods, as well as 3D brain imaging in live animals and humans. Exosomes are extracelluar membrane vesicles that facilitate communication between glia, and have significant potential for biomarker discovery and drug delivery. Polymorphisms in DNA repair genes may indirectly influence the structure and function of membrane proteins expressed in glial cells and predispose specific cell subgroups to degeneration. Physical exercise may reduce or retard age-related brain deterioration by a mechanism involving neuro-glial processes. It is most likely that additional information about the distribution, structure and function of glial cells will yield novel insight into human brain ageing. Systematic studies of glia and their functions are expected to eventually lead to earlier detection of ageing-related brain dysfunction and to interventions that could delay, reduce or prevent brain dysfunction. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Glial Cells and Chronic Pain

PubMed Central

GOSSELIN, ROMAIN-DANIEL; SUTER, MARC R.; JI, RU-RONG; DECOSTERD, ISABELLE

2010-01-01

Over the past few years, the control of pain exerted by glial cells has emerged as a promising target against pathological pain. Indeed, changes in glial phenotypes have been reported throughout the entire nociceptive pathway, from peripheral nerves to higher integrative brain regions and pharmacological inhibition of such glial reactions reduces the manifestation of pain in animal models. This complex interplay between glia and neurons relies on various mechanisms depending both on glial cell types considered (astrocytes, microglia, satellite cells or Schwann cells), the anatomical location of the regulatory process (peripheral nerve, spinal cord or brain) and the nature of the chronic pain paradigm. Intracellularly, recent advances have pointed out to the activation of specific cascades, such as mitogen associated protein kinases (MAPK) in the underlying processes behind glial activation. In addition, given the large number of functions accomplished by glial cells, various mechanisms might sensitize nociceptive neurons including a release of pronociceptive cytokines and neurotrophins or changes in neurotransmitter scavenging capacity. The authors review the conceptual advances made in the recent years about the implication of central and peripheral glia in animal models of chronic pain and discuss the possibility to translate it into human therapies in the future. PMID:20581331

Electrical Coupling Between Glial Cells in the Rat Retina

PubMed Central

Ceelen, Paul W.; Lockridge, Amber; Newman, Eric A.

2008-01-01

The strength of electrical coupling between retinal glial cells was quantified with simultaneous whole-cell current-clamp recordings from astrocyte–astrocyte, astrocyte–Müller cell, and Müller cell–Müller cell pairs in the acutely isolated rat retina. Experimental results were fit and space constants determined using a resistive model of the glial cell network that assumed a homogeneous two-dimensional glial syncytium. The effective space constant (the distance from the point of stimulation to where the voltage falls to 1/e) equaled 12.9, 6.2, and 3.7 µm, respectively for astrocyte–astrocyte, astrocyte–Müller cell, and Müller cell–Müller cell coupling. The addition of 1 mM Ba2+ had little effect on network space constants, while 0.5 mM octanol shortened the space constants to 4.7, 4.4, and 2.6 µm for the three types of coupling. For a given distance separating cell pairs, the strength of coupling showed considerable variability. This variability in coupling strength was reproduced accurately by a second resistive model of the glial cell network (incorporating discrete astrocytes spaced at varying distances from each other), demonstrating that the variability was an intrinsic property of the glial cell network. Coupling between glial cells in the retina may permit the intercellular spread of ions and small molecules, including messengers mediating Ca2+ wave propagation, but it is too weak to carry significant K+ spatial buffer currents. PMID:11424187

Acute and subacute IL-1β administrations differentially modulate neuroimmune and neurotrophic systems: possible implications for neuroprotection and neurodegeneration

PubMed Central

2013-01-01

Background In Alzheimer’s disease, stroke and brain injuries, activated microglia can release proinflammatory cytokines, such as interleukin (IL)-1β. These cytokines may change astrocyte and neurotrophin functions, which influences neuronal survival and induces apoptosis. However, the interaction between neuroinflammation and neurotrophin functions in different brain conditions is unknown. The present study hypothesized that acute and subacute elevated IL-1β differentially modulates glial and neurotrophin functions, which are related to their role in neuroprotection and neurodegeneration. Method Rats were i.c.v. injected with saline or IL-1β for 1 or 8 days and tested in a radial maze. mRNA and protein expressions of glial cell markers, neurotrophins, neurotrophin receptors, β-amyloid precursor protein (APP) and the concentrations of pro- and anti-inflammatory cytokines were measured in the hippocampus. Results When compared to controls, memory deficits were found 4 days after IL-1 administrations, however the deficits were attenuated by IL-1 receptor antagonist (RA). Subacute IL-1 administrations increased expressions of APP, microglial active marker CD11b, and p75 neurotrophin receptor, and the concentration of tumor necrosis factor (TNF)-α and IL-1β, but decreased expressions of astrocyte active marker glial fibrillary acidic protein (GFAP), brain-derived neurotrophic factor (BDNF) and TrK B. By contrast, up-regulations of NGF, BDNF and TrK B expressions were found after acute IL-1 administration, which are associated with the increase in both glial marker expressions and IL-10 concentrations. However, TrK A was down-regulated by acute and up-regulated by subacute IL-1 administrations. Subacute IL-1-induced changes in the glial activities, cytokine concentrations and expressions of BDNF and p75 were reversed by IL-1RA treatment. Conclusion These results indicate that acute and subacute IL-1 administrations induce different changes toward neuroprotection after acute IL-1 administrations but neurodegeneration after subacute ones. PMID:23651534

Axonal ensheathment and septate junction formation in the peripheral nervous system of Drosophila.

PubMed

Banerjee, Swati; Pillai, Anilkumar M; Paik, Raehum; Li, Jingjun; Bhat, Manzoor A

2006-03-22

Axonal insulation is critical for efficient action potential propagation and normal functioning of the nervous system. In Drosophila, the underlying basis of nerve ensheathment is the axonal insulation by glial cells and the establishment of septate junctions (SJs) between glial cell membranes. However, the details of the cellular and molecular mechanisms underlying axonal insulation and SJ formation are still obscure. Here, we report the characterization of axonal insulation in the Drosophila peripheral nervous system (PNS). Targeted expression of tau-green fluorescent protein in the glial cells and ultrastructural analysis of the peripheral nerves allowed us to visualize the glial ensheathment of axons. We show that individual or a group of axons are ensheathed by inner glial processes, which in turn are ensheathed by the outer perineurial glial cells. SJs are formed between the inner and outer glial membranes. We also show that Neurexin IV, Contactin, and Neuroglian are coexpressed in the peripheral glial membranes and that these proteins exist as a complex in the Drosophila nervous system. Mutations in neurexin IV, contactin, and neuroglian result in the disruption of blood-nerve barrier function in the PNS, and ultrastructural analyses of the mutant embryonic peripheral nerves show loss of glial SJs. Interestingly, the murine homologs of Neurexin IV, Contactin, and Neuroglian are expressed at the paranodal SJs and play a key role in axon-glial interactions of myelinated axons. Together, our data suggest that the molecular machinery underlying axonal insulation and axon-glial interactions may be conserved across species.

Effects of oxidative stress on hyperglycaemia-induced brain malformations in a diabetes mouse model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Ya; Wang, Guang; Han, Sha-Sha

Pregestational diabetes mellitus (PGDM) enhances the risk of fetal neurodevelopmental defects. However, the mechanism of hyperglycaemia-induced neurodevelopmental defects is not fully understood. In this study, several typical neurodevelopmental defects were identified in the streptozotocin-induced diabetes mouse model. The neuron-specific class III beta-tubulin/forkhead box P1-labelled neuronal differentiation was suppressed and glial fibrillary acidic protein-labelled glial cell lineage differentiation was slightly promoted in pregestational diabetes mellitus (PGDM) mice. Various concentrations of glucose did not change the U87 cell viability, but glial cell line-derived neurotrophic factor expression was altered with varying glucose concentrations. Mouse maternal hyperglycaemia significantly increased Tunel{sup +} apoptosis but didmore » not dramatically affect PCNA{sup +} cell proliferation in the process. To determine the cause of increased apoptosis, we determined the SOD activity, the expression of Nrf2 as well as its downstream anti-oxidative factors NQO1 and HO1, and found that all of them significantly increased in PGDM fetal brains compared with controls. However, Nrf2 expression in U87 cells was not significantly changed by different glucose concentrations. In mouse telencephalon, we observed the co-localization of Tuj-1 and Nrf2 expression in neurons, and down-regulating of Nrf2 in SH-SY5Y cells altered the viability of SH-SY5Y cells exposed to high glucose concentrations. Taken together, the data suggest that Nrf2-modulated antioxidant stress plays a crucial role in maternal hyperglycaemia-induced neurodevelopmental defects. - Highlights: • Typical neurodevelopmental defects could be observed in STZ-treated mouse fetuses. • Nrf2 played a crucial role in hyperglycaemia-induced brain malformations. • The effects of hyperglycaemia on neurons and glia cells were not same.« less

Neuroglia in ageing and disease.

PubMed

Verkhratsky, Alexei; Rodríguez, José J; Parpura, Vladimir

2014-08-01

The proper operation of the mammalian brain requires dynamic interactions between neurones and glial cells. Various types of glial cells are susceptible to morpho-functional changes in a variety of brain pathological states, including toxicity, neurodevelopmental, neurodegenerative and psychiatric disorders. Morphological modifications include a change in the glial cell size and shape; the latter is evident by changes of the appearance and number of peripheral processes. The most blatant morphological change is associated with the alteration of the sheer number of neuroglia cells in the brain. Functionally, glial cells can undergo various metabolic and biochemical changes, the majority of which reflect upon homeostasis of neurotransmitters, in particular that of glutamate, as well as on defence mechanisms provided by neuroglia. Not only glial cells exhibit changes associated with the pathology of the brain but they also change with brain aging.

Multifunctional glial support by Semper cells in the Drosophila retina

PubMed Central

Charlton-Perkins, Mark A.

2017-01-01

Glial cells play structural and functional roles central to the formation, activity and integrity of neurons throughout the nervous system. In the retina of vertebrates, the high energetic demand of photoreceptors is sustained in part by Müller glia, an intrinsic, atypical radial glia with features common to many glial subtypes. Accessory and support glial cells also exist in invertebrates, but which cells play this function in the insect retina is largely undefined. Using cell-restricted transcriptome analysis, here we show that the ommatidial cone cells (aka Semper cells) in the Drosophila compound eye are enriched for glial regulators and effectors, including signature characteristics of the vertebrate visual system. In addition, cone cell-targeted gene knockdowns demonstrate that such glia-associated factors are required to support the structural and functional integrity of neighboring photoreceptors. Specifically, we show that distinct support functions (neuronal activity, structural integrity and sustained neurotransmission) can be genetically separated in cone cells by down-regulating transcription factors associated with vertebrate gliogenesis (pros/Prox1, Pax2/5/8, and Oli/Olig1,2, respectively). Further, we find that specific factors critical for glial function in other species are also critical in cone cells to support Drosophila photoreceptor activity. These include ion-transport proteins (Na/K+-ATPase, Eaat1, and Kir4.1-related channels) and metabolic homeostatic factors (dLDH and Glut1). These data define genetically distinct glial signatures in cone/Semper cells that regulate their structural, functional and homeostatic interactions with photoreceptor neurons in the compound eye of Drosophila. In addition to providing a new high-throughput model to study neuron-glia interactions, the fly eye will further help elucidate glial conserved "support networks" between invertebrates and vertebrates. PMID:28562601

The Search for True Numbers of Neurons and Glial Cells in the Human Brain: A Review of 150 Years of Cell Counting

PubMed Central

von Bartheld, Christopher S.; Bahney, Jami; Herculano-Houzel, Suzana

2016-01-01

For half a century, the human brain was believed to contain about 100 billion neurons and one trillion glial cells, with a glia:neuron ratio of 10:1. A new counting method, the isotropic fractionator, has challenged the notion that glia outnumber neurons and revived a question that was widely thought to have been resolved. The recently validated isotropic fractionator demonstrates a glia:neuron ratio of less than 1:1 and a total number of less than 100 billion glial cells in the human brain. A survey of original evidence shows that histological data always supported a 1:1 ratio of glia to neurons in the entire human brain, and a range of 40–130 billion glial cells. We review how the claim of one trillion glial cells originated, was perpetuated, and eventually refuted. We compile how numbers of neurons and glial cells in the adult human brain were reported and we examine the reasons for an erroneous consensus about the relative abundance of glial cells in human brains that persisted for half a century. Our review includes a brief history of cell counting in human brains, types of counting methods that were and are employed, ranges of previous estimates, and the current status of knowledge about the number of cells. We also discuss implications and consequences of the new insights into true numbers of glial cells in the human brain, and the promise and potential impact of the newly validated isotropic fractionator for reliable quantification of glia and neurons in neurological and psychiatric diseases. PMID:27187682

The search for true numbers of neurons and glial cells in the human brain: A review of 150 years of cell counting.

PubMed

von Bartheld, Christopher S; Bahney, Jami; Herculano-Houzel, Suzana

2016-12-15

For half a century, the human brain was believed to contain about 100 billion neurons and one trillion glial cells, with a glia:neuron ratio of 10:1. A new counting method, the isotropic fractionator, has challenged the notion that glia outnumber neurons and revived a question that was widely thought to have been resolved. The recently validated isotropic fractionator demonstrates a glia:neuron ratio of less than 1:1 and a total number of less than 100 billion glial cells in the human brain. A survey of original evidence shows that histological data always supported a 1:1 ratio of glia to neurons in the entire human brain, and a range of 40-130 billion glial cells. We review how the claim of one trillion glial cells originated, was perpetuated, and eventually refuted. We compile how numbers of neurons and glial cells in the adult human brain were reported and we examine the reasons for an erroneous consensus about the relative abundance of glial cells in human brains that persisted for half a century. Our review includes a brief history of cell counting in human brains, types of counting methods that were and are employed, ranges of previous estimates, and the current status of knowledge about the number of cells. We also discuss implications and consequences of the new insights into true numbers of glial cells in the human brain, and the promise and potential impact of the newly validated isotropic fractionator for reliable quantification of glia and neurons in neurological and psychiatric diseases. J. Comp. Neurol. 524:3865-3895, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

C-Phycocyanin protects against acute tributyltin chloride neurotoxicity by modulating glial cell activity along with its anti-oxidant and anti-inflammatory property: A comparative efficacy evaluation with N-acetyl cysteine in adult rat brain.

PubMed

Mitra, Sumonto; Siddiqui, Waseem A; Khandelwal, Shashi

2015-08-05

Spirulina is a widely used health supplement and is a dietary source of C-Phycocyanin (CPC), a potent anti-oxidant. We have previously reported the neurotoxic potential of tributyltin chloride (TBTC), an environmental pollutant and potent biocide. In this study, we have evaluated the protective efficacy of CPC against TBTC induced neurotoxicity. To evaluate the extent of neuroprotection offered by CPC, its efficacy was compared with the degree of protection offered by N-acetylcysteine (NAC) (a well known neuroprotective drug, taken as a positive control). Male Wistar rats (28 day old) were administered with 20mg/kg TBTC (oral) and 50mg/kg CPC or 50mg/kg NAC (i.p.), alone or in combination, and various parameters were evaluated. These include blood-brain barrier (BBB) damage; redox parameters (ROS, GSH, redox pathway associated enzymes, oxidative stress markers); inflammatory, cellular, and stress markers; apoptotic proteins and in situ cell death assay (TUNEL). We observed increased CPC availability in cortical tissue following its administration. Although BBB associated proteins like claudin-5, p-glycoprotein and ZO-1 were restored, CPC/NAC failed to protect against TBTC induced overall BBB permeability (Evans blue extravasation). Both CPC and NAC remarkably reduced oxidative stress and inflammation. NAC effectively modulated redox pathway associated enzymes whereas CPC countered ROS levels efficiently. Interestingly, CPC and NAC were equivalently capable of reducing apoptotic markers, astroglial activation and cell death. This study illustrates the various pathways involved in CPC mediated neuroprotection against this environmental neurotoxicant and highlights its capability to modulate glial cell activity. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Label-free distinguishing between neurons and glial cells based on two-photon excited fluorescence signal of neuron perinuclear granules

NASA Astrophysics Data System (ADS)

Du, Huiping; Jiang, Liwei; Wang, Xingfu; Liu, Gaoqiang; Wang, Shu; Zheng, Liqin; Li, Lianhuang; Zhuo, Shuangmu; Zhu, Xiaoqin; Chen, Jianxin

2016-08-01

Neurons and glial cells are two critical cell types of brain tissue. Their accurate identification is important for the diagnosis of psychiatric disorders such as depression and schizophrenia. In this paper, distinguishing between neurons and glial cells by using the two-photon excited fluorescence (TPEF) signals of intracellular intrinsic sources was performed. TPEF microscopy combined with TUJ-1 and GFAP immunostaining and quantitative image analysis demonstrated that the perinuclear granules of neurons in the TPEF images of brain tissue and the primary cultured cortical cells were a unique characteristic of neurons compared to glial cells which can become a quantitative feature to distinguish neurons from glial cells. With the development of miniaturized TPEF microscope (‘two-photon fiberscopes’) imaging devices, TPEF microscopy can be developed into an effective diagnostic and monitoring tool for psychiatric disorders such as depression and schizophrenia.

Oligodendrocyte-Neuron Interactions: Impact on Myelination and Brain Function.

PubMed

Shimizu, Takeshi; Osanai, Yasuyuki; Ikenaka, Kazuhiro

2018-01-01

In the past, glial cells were considered to be 'glue' cells whose primary role was thought to be merely filling gaps in neural circuits. However, a growing number of reports have indicated the role of glial cells in higher brain function through their interaction with neurons. Myelin was originally thought to be just a sheath structure surrounding neuronal axons, but recently it has been shown that myelin exerts effects on the conduction velocity of neuronal axons even after myelin formation. Therefore, the investigation of glial cell properties and the neuron-glial interactions is important for understanding higher brain function. Moreover, since there are many neurological disorders caused by glial abnormalities, further understanding of glial cell-related diseases and the development of effective therapeutic strategies are warranted. In this review, we focused on oligodendrocyte-neuron interactions, with particular attention on (1) axonal signals underlying oligodendrocyte differentiation and myelination, (2) neuronal activity-dependent myelination and (3) the effects of myelination on higher brain function.

Motile membrane protrusions regulate cell-cell adhesion and migration of olfactory ensheathing glia.

PubMed

Windus, Louisa C E; Claxton, Christina; Allen, Chelsea L; Key, Brian; St John, James A

2007-12-01

Olfactory ensheathing cells (OECs) are candidates for therapeutic approaches for neural regeneration due to their ability to assist axon regrowth in central nervous system lesion models. However, little is understood about the processes and mechanisms underlying migration of these cells. We report here that novel lamellipodial protrusions, termed lamellipodial waves, are integral to OEC migration. Time-lapse imaging of migrating OECs revealed that these highly dynamic waves progress along the shaft of the cells and are crucial for mediating cell-cell adhesion. Without these waves, cell-cell adhesion does not occur and migrational rates decline. The activity of waves is modulated by both glial cell line-derived neurotrophic factor and inhibitors of the JNK and SRC kinases. Furthermore, the activity of lamellipodial waves can be modulated by Mek1, independently of leading edge activity. The ability to selectively regulate cell migration via lamellipodial waves has implications for manipulating the migratory behavior of OECs during neural repair. (c) 2007 Wiley-Liss, Inc.

Endogenous pleiotrophin and midkine regulate LPS-induced glial responses.

PubMed

Fernández-Calle, Rosalía; Vicente-Rodríguez, Marta; Gramage, Esther; de la Torre-Ortiz, Carlos; Pérez-García, Carmen; Ramos, María P; Herradón, Gonzalo

2018-01-01

Pleiotrophin (PTN) and Midkine (MK) are two growth factors that modulate neuroinflammation. PTN overexpression in the brain prevents LPS-induced astrocytosis in mice but potentiates microglial activation. The modest astrocytic response caused by a low dose of LPS (0.5mg/kg) is blocked in the striatum of MK-/- mice whereas microglial response is unaffected. We have now tested the effects of an intermediate dose of LPS (7.5mg/kg) in glial response in PTN-/- and MK-/- mice. We found that LPS-induced astrocytosis is prevented in prefrontal cortex and striatum of both PTN-/- and MK-/- mice. Some of the morphological changes of microglia induced by LPS tended to increase in both genotypes, particularly in PTN-/- mice. Since we previously showed that PTN potentiates LPS-induced activation of BV2 microglial cells, we tested the activation of FYN kinase, a substrate of the PTN receptor RPTPβ/ζ, and the subsequent ERK1/2 phosphorylation on LPS and PTN-treated BV2 cells. LPS effects on BV2 cells were not affected by the addition of PTN, suggesting that PTN does not recruit the FYN-MAP kinase signaling pathway in order to modulate LPS effects on microglial cells. Taking together, evidences demonstrate that regulation of astroglial responses to LPS administration are highly dependent on the levels of expression of PTN and MK. Further studies are needed to clarify the possible roles of endogenous expression of PTN and MK in LPS-induced microglial responses. Copyright © 2017 Elsevier B.V. All rights reserved.

c-erbA and v-erbA modulate growth and gene expression of a mouse glial precursor cell line.

PubMed

Iglesias, T; Llanos, S; López-Barahona, M; Pérez-Aranda, A; Rodríguez-Peña, A; Bernal, J; Höhne, A; Seliger, B; Muñoz, A

1994-07-01

The c-erbA alpha protooncogene coding for the thyroid hormone (T3) receptor (TR alpha 1) and the viral, mutated v-erbA oncogene were expressed in an immortal mouse glial cell line (B3.1) using retroviral vectors. c-erbA alpha expression led to a decrease in cell proliferation in high and low serum conditions, both in the presence and in the absence of T3. In serum-free medium, c-erbA-expressing cells (B3.1 + TR alpha 1) were completely arrested, whereas cells expressing v-erbA (B3.1 + v-erbA) showed a higher DNA synthesis rate than normal B3.1 cells. Although proliferation of all three cell types was stimulated by platelet-derived growth factor and basic fibroblast growth factor, differences were also observed in the response to these agents. B3.1 + TR alpha 1 cells were more sensitive to platelet-derived growth factor than B3.1 and B3.1 + v-erbA cells. In contrast, B3.1 cells responded to basic fibroblast growth factor better than B3.1 + TR alpha 1 or B3.1 + v-erbA cells. Insulin-like growth factor I potentiated the action of platelet-derived growth factor and basic fibroblast growth factor. Again, different responses to treatment with insulin-like growth factor I alone were observed; B3.1 + TR alpha 1 cells did not respond to it, whereas B3.1 + v-erbA cells showed a dramatic stimulation by this agent. Interestingly, in the presence of T3, the blockade in B3.1 + TR alpha 1 cell proliferation was accompanied by the down-regulation of the typical astrocytic genes, glial fibrillary acidic protein and vimentin. These hormone effects were not found in v-erbA-expressing cells. In addition, v-erbA inhibited the basal expression of the cyclic nucleotide phosphodiesterase gene, an oligodendrocytic marker.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a cis-acting element involved in cell-specific expression of the zebrafish brain aromatase gene.

PubMed

Le Page, Yann; Menuet, Arnaud; Kah, Olivier; Pakdel, Farzad

2008-10-01

The cytochrome P450 Aromatase is the key enzyme catalyzing the conversion of androgens into estrogens. In zebrafish, the brain aromatase is encoded by cyp19b. Expression of cyp19b is restricted to radial glial cells bordering forebrain ventricles and is strongly stimulated by estrogens during development. At the promoter level, we have previously shown that an estrogen responsive element (ERE) is required for induction by estrogens. Here, we investigated the role of ERE flanking regions in the control of cell-specific expression. First, we show that a 20 bp length motif, named G x RE (glial x responsive element), acts in synergy with the ERE to mediate the estrogenic induction specifically in glial cells. Second, we demonstrate that, in vitro, this sequence binds factors exclusively present in glial or neuro-glial cells and is able to confer a glial specificity to an artificial estrogen-dependent gene. Taken together, these results contribute to the understanding of the molecular mechanisms allowing cyp19b regulation by estrogens and allowed to identify a promoter sequence involved in the strong estrogen inducibility of cyp19b which is specific for glial cells. The exceptional aromatase activity measured in the brain of teleost fish could rely on such mechanisms.

Ghrelin is involved in the paracrine communication between neurons and glial cells.

PubMed

Avau, B; De Smet, B; Thijs, T; Geuzens, A; Tack, J; Vanden Berghe, P; Depoortere, I

2013-09-01

Ghrelin is the only known peripherally active orexigenic hormone produced by the stomach that activates vagal afferents to stimulate food intake and to accelerate gastric emptying. Vagal sensory neurons within the nodose ganglia are surrounded by glial cells, which are able to receive and transmit chemical signals. We aimed to investigate whether ghrelin activates or influences the interaction between both types of cells. The effect of ghrelin was compared with that of leptin and cholecystokinin (CCK). Cultures of rat nodose ganglia were characterized by immunohistochemistry and the functional effects of peptides, neurotransmitters, and pharmacological blockers were measured by Ca(2+) imaging using Fluo-4-AM as an indicator. Neurons responded to KCl and were immunoreactive for PGP-9.5 whereas glial cells responded to lysophosphatidic acid and had the typical SOX-10-positive nuclear staining. Neurons were only responsive to CCK (31 ± 5%) whereas glial cells responded equally to the applied stimuli: ghrelin (27 ± 2%), leptin (21 ± 2%), and CCK (30 ± 2%). In contrast, neurons stained more intensively for the ghrelin receptor than glial cells. ATP induced [Ca(2+) ]i rises in 90% of the neurons whereas ACh and the NO donor, SIN-1, mainly induced [Ca(2+) ]i changes in glial cells (41 and 51%, respectively). The percentage of ghrelin-responsive glial cells was not affected by pretreatment with suramin, atropine, hexamethonium or 1400 W, but was reduced by l-NAME and by tetrodotoxin. Neurons were shown to be immunoreactive for neuronal NO-synthase (nNOS). Our data show that ghrelin induces Ca(2+) signaling in glial cells of the nodose ganglion via the release of NO originating from the neurons. © 2013 John Wiley & Sons Ltd.

Hybrid Thin Film Organosilica Sol-Gel Coatings To Support Neuronal Growth and Limit Astrocyte Growth.

PubMed

Capeletti, Larissa Brentano; Cardoso, Mateus Borba; Dos Santos, João Henrique Zimnoch; He, Wei

2016-10-07

Thin films of silica prepared by a sol-gel process are becoming a feasible coating option for surface modification of implantable neural sensors without imposing adverse effects on the devices' electrical properties. In order to advance the application of such silica-based coatings in the context of neural interfacing, the characteristics of silica sol-gel are further tailored to gain active control of interactions between cells and the coating materials. By incorporating various readily available organotrialkoxysilanes carrying distinct organic functional groups during the sol-gel process, a library of hybrid organosilica coatings is developed and investigated. In vitro neural cultures using PC12 cells and primary cortical neurons both reveal that, among these different types of hybrid organosilica, the introduction of aminopropyl groups drastically transforms the silica into robust neural permissive substrate, supporting neuron adhesion and neurite outgrowth. Moreover, when this organosilica is cultured with astrocytes, a key type of glial cells responsible for glial scar response toward neural implants, such cell growth promoting effect is not observed. These findings highlight the potential of organo-group-bearing silica sol-gel to function as advanced coating materials to selectively modulate cell response and promote neural integration with implantable sensing devices.

Activation of mixed glia by Abeta-specific Th1 and Th17 cells and its regulation by Th2 cells.

PubMed

McQuillan, K; Lynch, Marina A; Mills, Kingston H G

2010-05-01

Microglia are innate immune cells of the CNS, that act as antigen-presenting cells (APC) for antigen-specific T cells and respond to inflammatory stimuli, such as amyloid-beta (Abeta), resulting in the release of neurotoxic factors and pro-inflammatory cytokines. Astrocytes can also act as APC and modulate the function of microglia. However, the role of distinct T cell subtypes, in particular Th17 cells, in glial activation and subsequent modulatory effects of Th2 cells are poorly understood. Here, we generated Abeta-specific Th1, Th2, and Th17 cells and examined their role in modulating Abeta-induced activation of microglia in a mixed glial culture, a preparation which mimics the complex APC types in the brain. We demonstrated that mixed glia acted as an effective APC for Abeta-specific Th1 and Th17 cells. Addition of Abeta-specific Th2 cells suppressed the Abeta-induced IFN-gamma production by Th1 cells and IL-17 production by Th17 cells with glia as the APC. Co-culture of Abeta-specific Th1 or Th17 cells with glia markedly enhanced Abeta-induced pro-inflammatory cytokine production and expression of MHC class II and co-stimulatory molecules on the microglia. Addition of Abeta-specific Th2 cells inhibited Th17 cell-induced IL-1beta and IL-6 production by mixed glia and attenuated Th1 cell-induced CD86 and CD40 expression on microglia. The modest enhancement of MHC class II and CD86 expression on astrocytes by Abeta-specific Th1 and Th17 was not attenuated by Th2 cells. These data indicate that Abeta-specific Th1 and Th17 cells induce inflammatory activation of glia, and that this is in part regulated by Th2 cells. Copyright 2010 Elsevier Inc. All rights reserved.

Comparative survival study of glial cells and cells composing walls of blood vessels in crustacean ventral nerve cord after photodynamic treatment

NASA Astrophysics Data System (ADS)

Kolosov, Mikhail S.; Shubina, Elena

2015-03-01

Photodynamic therapy is a prospective treatment modality of brain cancers. It is of importance to have information about relative survival rate of different cell types in nerve tissue during photodynamic treatment. Particularly, for development of sparing strategy of the photodynamic therapy of brain tumors, which pursuits both total elimination of malignant cells, which are usually of glial origin, and, at the same time, preservation of normal blood circulation as well as normal glial cells in the brain. The aim of this work was to carry out comparative survival study of glial cells and cells composing walls of blood vessels after photodynamic treatment, using simple model object - ventral nerve cord of crustacean.

Live Imaging of Glial Cell Migration in the Drosophila Eye Imaginal Disc

PubMed Central

Cafferty, Patrick; Xie, Xiaojun; Browne, Kristen; Auld, Vanessa J.

2009-01-01

Glial cells of both vertebrate and invertebrate organisms must migrate to final target regions in order to ensheath and support associated neurons. While recent progress has been made to describe the live migration of glial cells in the developing pupal wing (1), studies of Drosophila glial cell migration have typically involved the examination of fixed tissue. Live microscopic analysis of motile cells offers the ability to examine cellular behavior throughout the migratory process, including determining the rate of and changes in direction of growth. Paired with use of genetic tools, live imaging can be used to determine more precise roles for specific genes in the process of development. Previous work by Silies et al. (2) has described the migration of glia originating from the optic stalk, a structure that connects the developing eye and brain, into the eye imaginal disc in fixed tissue. Here we outline a protocol for examining the live migration of glial cells into the Drosophila eye imaginal disc. We take advantage of a Drosophila line that expresses GFP in developing glia to follow glial cell progression in wild type and in mutant animals. PMID:19590493

Radial glia - from boring cables to stem cell stars.

PubMed

Malatesta, Paolo; Götz, Magdalena

2013-02-01

The discovery in the year 2000 that radial glial cells act as neural stem and progenitor cells in development has led to a change in the concept of neural stem cells in the adult brain. Not only are adult stem cells in the neurogenic niches glial in nature, but also glial cells outside these niches display greater potential when reacting to brain injury. Thus, a concept that emerged from developmental studies may hold the clue for neural repair.

Distinctive glial and neuronal interfacing on nanocrystalline diamond.

PubMed

Bendali, Amel; Agnès, Charles; Meffert, Simone; Forster, Valérie; Bongrain, Alexandre; Arnault, Jean-Charles; Sahel, José-Alain; Offenhäusser, Andreas; Bergonzo, Philippe; Picaud, Serge

2014-01-01

Direct electrode/neuron interfacing is a key challenge to achieve high resolution of neuronal stimulation required for visual prostheses. Neuronal interfacing on biomaterials commonly requires the presence of glial cells and/or protein coating. Nanocrystalline diamond is a highly mechanically stable biomaterial with a remarkably large potential window for the electrical stimulation of tissues. Using adult retinal cell cultures from rats, we found that glial cells and retinal neurons grew equally well on glass and nanocrystalline diamond. The use of a protein coating increased cell survival, particularly for glial cells. However, bipolar neurons appeared to grow even in direct contact with bare diamond. We investigated whether the presence of glial cells contributed to this direct neuron/diamond interface, by using purified adult retinal ganglion cells to seed diamond and glass surfaces with and without protein coatings. Surprisingly, these fully differentiated spiking neurons survived better on nanocrystalline diamond without any protein coating. This greater survival was indicated by larger cell numbers and the presence of longer neurites. When a protein pattern was drawn on diamond, neurons did not grow preferentially on the coated area, by contrast to their behavior on a patterned glass. This study highlights the interesting biocompatibility properties of nanocrystalline diamond, allowing direct neuronal interfacing, whereas a protein coating was required for glial cell growth.

Distinctive Glial and Neuronal Interfacing on Nanocrystalline Diamond

PubMed Central

Bendali, Amel; Agnès, Charles; Meffert, Simone; Forster, Valérie; Bongrain, Alexandre; Arnault, Jean-Charles; Sahel, José-Alain; Offenhäusser, Andreas; Bergonzo, Philippe; Picaud, Serge

2014-01-01

Direct electrode/neuron interfacing is a key challenge to achieve high resolution of neuronal stimulation required for visual prostheses. Neuronal interfacing on biomaterials commonly requires the presence of glial cells and/or protein coating. Nanocrystalline diamond is a highly mechanically stable biomaterial with a remarkably large potential window for the electrical stimulation of tissues. Using adult retinal cell cultures from rats, we found that glial cells and retinal neurons grew equally well on glass and nanocrystalline diamond. The use of a protein coating increased cell survival, particularly for glial cells. However, bipolar neurons appeared to grow even in direct contact with bare diamond. We investigated whether the presence of glial cells contributed to this direct neuron/diamond interface, by using purified adult retinal ganglion cells to seed diamond and glass surfaces with and without protein coatings. Surprisingly, these fully differentiated spiking neurons survived better on nanocrystalline diamond without any protein coating. This greater survival was indicated by larger cell numbers and the presence of longer neurites. When a protein pattern was drawn on diamond, neurons did not grow preferentially on the coated area, by contrast to their behavior on a patterned glass. This study highlights the interesting biocompatibility properties of nanocrystalline diamond, allowing direct neuronal interfacing, whereas a protein coating was required for glial cell growth. PMID:24664111

Negative regulation of glial engulfment activity by Draper terminates glial responses to axon injury

PubMed Central

Logan, Mary A.; Hackett, Rachel; Doherty, Johnna; Sheehan, Amy; Speese, Sean D.; Freeman, Marc R.

2012-01-01

Neuronal injury elicits potent cellular responses from glia, but molecular pathways modulating glial activation, phagocytic function, and termination of reactive responses remain poorly defined. Here we show that positive or negative regulation of glial reponses to axon injury are molecularly encoded by unique isoforms of the Drosophila engulfment receptor Draper. Draper-I promotes engulfment of axonal debris through an immunoreceptor tyrosine-based activation motif (ITAM). In contrast, Draper-II, an alternative splice variant, potently inhibits glial engulfment function. Draper-II suppresses Draper-I signaling through a novel immunoreceptor tyrosine-based inhibitory motif (ITIM)-like domain and the tyrosine phosphatase Corkscrew (Csw). Intriguingly, loss of Draper-II/Csw signaling prolongs expression of glial engulfment genes after axotomy and reduces the ability of glia to respond to secondary axotomy. Our work highlights a novel role for Draper-II in inhibiting glial responses to neurodegeneration, and indicates a balance of opposing Draper-I/-II signaling events is essential to maintain glial sensitivity to brain injury. PMID:22426252

Role of Estrogens in the Size of Neuronal Somata of Paravaginal Ganglia in Ovariectomized Rabbits

PubMed Central

Hernández-Aragón, Laura G.; García-Villamar, Verónica; Carrasco-Ruiz, María de los Ángeles; Nicolás-Toledo, Leticia; Ortega, Arturo; Cuevas-Romero, Estela; Martínez-Gómez, Margarita

2017-01-01

We aimed to determine the role of estrogens in modulating the size of neuronal somata of paravaginal ganglia. Rabbits were allocated into control (C), ovariectomized (OVX), and OVX treated with estradiol benzoate (OVX + EB) groups to evaluate the neuronal soma area; total serum estradiol (E2) and testosterone (T) levels; the percentage of immunoreactive (ir) neurons anti-aromatase, anti-estrogen receptor (ERα, ERβ) and anti-androgen receptor (AR); the intensity of the immunostaining anti-glial cell line-derived neurotrophic factor (GDNF) and the GDNF family receptor alpha type 1 (GFRα1); and the number of satellite glial cells (SGCs) per neuron. There was a decrease in the neuronal soma size for the OVX group, which was associated with low T, high percentages of aromatase-ir and neuritic AR-ir neurons, and a strong immunostaining anti-GDNF and anti-GFRα1. The decrease in the neuronal soma size was prevented by the EB treatment that increased the E2 without affecting the T levels. Moreover, there was a high percentage of neuritic AR-ir neurons, a strong GDNF immunostaining in the SGC, and an increase in the SGCs per neuron. Present findings show that estrogens modulate the soma size of neurons of the paravaginal ganglia, likely involving the participation of the SGC. PMID:28316975

[Satellite glial cells in sensory ganglia: its role in pain].

PubMed

Costa, Filipa Alexandra Leite; Moreira Neto, Fani Lourença

2015-01-01

Satellite glial cells in sensory ganglia are a recent subject of research in the field of pain and a possible therapeutic target in the future. Therefore, the aim of this study was to summarize some of the important physiological and morphological characteristics of these cells and gather the most relevant scientific evidence about its possible role in the development of chronic pain. In the sensory ganglia, each neuronal body is surrounded by satellite glial cells forming distinct functional units. This close relationship enables bidirectional communication via a paracrine signaling between those two cell types. There is a growing body of evidence that glial satellite cells undergo structural and biochemical changes after nerve injury, which influence neuronal excitability and consequently the development and/or maintenance of pain in different animal models of chronic pain. Satellite glial cells are important in the establishment of physiological pain, in addition to being a potential target for the development of new pain treatments. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Modulation of Central Synapses by Astrocyte-Released ATP and Postsynaptic P2X Receptors

PubMed Central

Pankratov, Yuriy

2017-01-01

Communication between neuronal and glial cells is important for neural plasticity. P2X receptors are ATP-gated cation channels widely expressed in the brain where they mediate action of extracellular ATP released by neurons and/or glia. Recent data show that postsynaptic P2X receptors underlie slow neuromodulatory actions rather than fast synaptic transmission at brain synapses. Here, we review these findings with a particular focus on the release of ATP by astrocytes and the diversity of postsynaptic P2X-mediated modulation of synaptic strength and plasticity in the CNS. PMID:28845311

Characterization of glial-restricted precursors from rhesus monkey embryonic stem cells.

PubMed

Chen, Hongwei; Mao, Yu; Wang, Shufen; Li, Bin; Wang, Jinhuan; Li, Jian; Ma, Yuanye

2015-01-01

Glial-restricted precursor (GRP) cells, the earliest glial progenitors for both astrocytes and oligodendrocytes, have been derived from embryos and embryonic stem cells (ESC) in rodents. However, knowledge regarding the equivalent cell type in primates is limited due to restrictions imposed by ethics and resources. Here we report successful derivation and characterization of primate GRP cells from rhesus monkey ESC. The purified monkey GRP cells were A 2 B 5 -positive and FGF2-dependent for survival and proliferation. The differentiation assays indicated that they were tri-potential in vitro and bi-potential in vivo . These newly purified GRP cells will help to facilitate understanding of the molecular mechanism of glial development in primates as well as provide a source of therapeutic donor cells for use in neuroregenerative medicine.

Pharmacological blockade of either cannabinoid CB1 or CB2 receptors prevents both cocaine-induced conditioned locomotion and cocaine-induced reduction of cell proliferation in the hippocampus of adult male rat

PubMed Central

Blanco-Calvo, Eduardo; Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Pavón, Francisco Javier; Serrano, Antonia; Castilla-Ortega, Estela; Galeano, Pablo; Rubio, Leticia; Suárez, Juan; Rodriguez de Fonseca, Fernando

2014-01-01

Addiction to major drugs of abuse, such as cocaine, has recently been linked to alterations in adult neurogenesis in the hippocampus. The endogenous cannabinoid system modulates this proliferative response as demonstrated by the finding that pharmacological activation/blockade of cannabinoid CB1 and CB2 receptors not only modulates neurogenesis but also modulates cell death in the brain. In the present study, we evaluated whether the endogenous cannabinoid system affects cocaine-induced alterations in cell proliferation. To this end, we examined whether pharmacological blockade of either CB1 (Rimonabant, 3 mg/kg) or CB2 receptors (AM630, 3 mg/kg) would affect cell proliferation [the cells were labeled with 5-bromo-2′-deoxyuridine (BrdU)] in the subventricular zone (SVZ) of the lateral ventricle and the dentate subgranular zone (SGZ). Additionally, we measured cell apoptosis (as monitored by the expression of cleaved caspase-3) and glial activation [by analyzing the expression of glial fibrillary acidic protein (GFAP) and Iba-1] in the striatum and hippocampus during acute and repeated (4 days) cocaine administration (20 mg/kg). The results showed that acute cocaine exposure decreased the number of BrdU-immunoreactive (ir) cells in the SVZ and SGZ. In contrast, repeated cocaine exposure reduced the number of BrdU-ir cells only in the SVZ. Both acute and repeated cocaine exposure increased the number of cleaved caspase-3-, GFAP- and Iba1-ir cells in the hippocampus, and this effect was counteracted by AM630 or Rimonabant, which increased the number of BrdU-, GFAP-, and Iba1-ir cells in the hippocampus. These results indicate that the changes in neurogenic, apoptotic and gliotic processes that were produced by repeated cocaine administration were normalized by pharmacological blockade of CB1 and CB2. The restorative effects of cannabinoid receptor blockade on hippocampal cell proliferation were associated with the prevention of the induction of conditioned locomotion but not with the prevention of cocaine-induced sensitization. PMID:24409127

Endosomal accumulation of Toll-like receptor 4 causes constitutive secretion of cytokines and activation of signal transducers and activators of transcription in Niemann-Pick disease type C (NPC) fibroblasts: a potential basis for glial cell activation in the NPC brain.

PubMed

Suzuki, Michitaka; Sugimoto, Yuko; Ohsaki, Yuki; Ueno, Makoto; Kato, Shinsuke; Kitamura, Yukisato; Hosokawa, Hiroshi; Davies, Joanna P; Ioannou, Yiannis A; Vanier, Marie T; Ohno, Kousaku; Ninomiya, Haruaki

2007-02-21

Niemann-Pick disease type C (NPC) is an inherited lipid storage disorder caused by mutations in NPC1 or NPC2 genes. Loss of function of either protein results in the endosomal accumulation of cholesterol and other lipids, progressive neurodegeneration, and robust glial cell activation. Here, we report that cultured human NPC fibroblasts secrete interferon-beta, interleukin-6 (IL-6), and IL-8, and contain increased levels of signal transducers and activators of transcription (STATs). These cells also contained increased levels of Toll-like receptor 4 (TLR4) that accumulated in cholesterol-enriched endosomes/lysosomes, and small interfering RNA knockdown of this receptor reduced cytokine secretion. In the NPC1-/- mouse brain, glial cells expressed TLR4 and IL-6, whereas both glial and neuronal cells expressed STATs. Genetic deletion of TLR4 in NPC1-/- mice reduced IL-6 secretion by cultured fibroblasts but failed to alter STAT levels or glial cell activation in the brain. In contrast, genetic deletion of IL-6 normalized STAT levels and suppressed glial cell activation. These findings indicate that constitutive cytokine secretion leads to activation of STATs in NPC fibroblasts and that this secretion is partly caused by an endosomal accumulation of TLR4. These results also suggest that similar signaling events may underlie glial cell activation in the NPC1-/- mouse brain.

New tools for the analysis of glial cell biology in Drosophila.

PubMed

Awasaki, Takeshi; Lee, Tzumin

2011-09-01

Because of its genetic, molecular, and behavioral tractability, Drosophila has emerged as a powerful model system for studying molecular and cellular mechanisms underlying the development and function of nervous systems. The Drosophila nervous system has fewer neurons and exhibits a lower glia:neuron ratio than is seen in vertebrate nervous systems. Despite the simplicity of the Drosophila nervous system, glial organization in flies is as sophisticated as it is in vertebrates. Furthermore, fly glial cells play vital roles in neural development and behavior. In addition, powerful genetic tools are continuously being created to explore cell function in vivo. In taking advantage of these features, the fly nervous system serves as an excellent model system to study general aspects of glial cell development and function in vivo. In this article, we review and discuss advanced genetic tools that are potentially useful for understanding glial cell biology in Drosophila. Copyright © 2011 Wiley-Liss, Inc.

Sodium channels in axons and glial cells of the optic nerve of Necturus maculosa.

PubMed

Tang, C M; Strichartz, G R; Orkand, R K

1979-11-01

Experiments investigating both the binding of radioactively labelled saxitoxin (STX) and the electrophysiological response to drugs that increase the sodium permeability of excitable membranes were conducted in an effort to detect sodium channels in glial cells of the optic nerve of Necturus maculosa, the mudpuppy. Glial cells in nerves from chronically enucleated animals, which lack optic nerve axons, show no saturable uptake of STX whereas a saturable uptake is clearly present in normal optic nerves. The normal nerve is depolarized by aconitine, batrachotoxin, and veratridine (10(-6)-10(-5) M), whereas the all-glial preparation is only depolarized by veratridine and at concentrations greater than 10(-3) M. Unlike the depolarization caused by veratridine in normal nerves, the response in the all-glial tissue is not blocked by tetrodotoxin nor enhanced by scorpion venom (Leiurus quinquestriatus). In glial cells of the normal nerve, where axons are also present, the addition of 10(-5) M veratridine does lead to a transient depolarization; however, it is much briefer than the axonal response to veratridine in this same tissue. This glial response to veratridine could be caused by the efflux of K+ from the drug-depolarized axons, and is similar to the glial response to extracellular K+ accumulation resulting from action potentials in the axon.

Sodium channels in axons and glial cells of the optic nerve of Necturus maculosa

PubMed Central

1979-01-01

Experiments investigating both the binding of radioactively labelled saxitoxin (STX) and the electrophysiological response to drugs that increase the sodium permeability of excitable membranes were conducted in an effort to detect sodium channels in glial cells of the optic nerve of Necturus maculosa, the mudpuppy. Glial cells in nerves from chronically enucleated animals, which lack optic nerve axons, show no saturable uptake of STX whereas a saturable uptake is clearly present in normal optic nerves. The normal nerve is depolarized by aconitine, batrachotoxin, and veratridine (10(-6)-10(-5) M), whereas the all-glial preparation is only depolarized by veratridine and at concentrations greater than 10(-3) M. Unlike the depolarization caused by veratridine in normal nerves, the response in the all-glial tissue is not blocked by tetrodotoxin nor enhanced by scorpion venom (Leiurus quinquestriatus). In glial cells of the normal nerve, where axons are also present, the addition of 10(-5) M veratridine does lead to a transient depolarization; however, it is much briefer than the axonal response to veratridine in this same tissue. This glial response to veratridine could be caused by the efflux of K+ from the drug- depolarized axons, and is similar to the glial response to extracellular K+ accumulation resulting from action potentials in the axon. PMID:512633

The L1-CAM, Neuroglian, functions in glial cells for Drosophila antennal lobe development.

PubMed

Chen, Weitao; Hing, Huey

2008-07-01

Although considerable progress has been made in understanding the roles of olfactory receptor neurons (ORNs) and projection neurons (PNs) in Drosophila antennal lobe (AL) development, the roles of glia have remained largely mysterious. Here, we show that during Drosophila metamorphosis, a population of midline glial cells in the brain undergoes extensive cellular remodeling and is closely associated with the collateral branches of ORN axons. These glial cells are required for ORN axons to project across the midline and establish the contralateral wiring in the ALs. We find that Neuroglian (Nrg), the Drosophila homolog of the vertebrate cell adhesion molecule, L1, is expressed and functions in the midline glial cells to regulate their proper development. Loss of Nrg causes the disruption in glial morphology and the agenesis of the antennal commissural tract. Our genetic analysis further demonstrates that the functions of Nrg in the midline glia require its ankyrin-binding motif. We propose that Nrg is an important regulator of glial morphogenesis and axon guidance in AL development. (Copyright) 2008 Wiley Periodicals, Inc.

The chemokine CXCL16 induces migration and invasion of glial precursor cells via its receptor CXCR6.

PubMed

Hattermann, Kirsten; Ludwig, Andreas; Gieselmann, Volkmar; Held-Feindt, Janka; Mentlein, Rolf

2008-09-01

Chemokines are implicated in developmental and inflammatory processes in the brain. The transmembrane chemokine CXCL16 is produced in brain endothelial and reactive astroglial cells and released by shedding. Its receptor CXCR6 is detected during brain development highest at postnatal day 6, found in glial precursor cells differentiated from neural stem cells and in an A2B5-positive glial precursor cell line. Their stimulation by soluble CXCL16 induces the PI3-kinase/Akt and Erk pathways resulting in the activation of the transcription factor AP-1. As biological responses, soluble CXCL16 upregulates its own receptor, increases cell proliferation, stimulates cell migration in wound-healing and in spheroid confrontation assays. Invasion of CXCR6-positive glial cells into CXCL16-expressing spheroids can be blocked by sheddase inhibitors and CXCL16-antibody. Since CXCL16 is induced by cytokines at sites of inflammation, neurodegeneration, ischemia and malignant transformation, it should attract CXCR6-positive glial precursor cells, enhance their invasion and proliferation and thus favor astrogliosis.

Targeting Microglia to Prevent Post-Traumatic Epilepsy

DTIC Science & Technology

2012-07-01

long-term effects of nigral lipopolysaccharide administration on dopaminergic dysfunction and glial cell activation. Eur J Neurosci 22 :317-330...attenuating damaging effects of hyperexcitability in the brain induced by inflammation resulting from glial cell immune responses to trauma. We are...damaging effects of hyperexcitability in the brain induced by inflammation resulting from glial cell immune responses to trauma. We are exploring two

Targeting Microglia to Prevent Post-Traumatic Epilepsy

DTIC Science & Technology

2013-07-01

LFPI). Our focus is on attenuating damaging effects of hyperexcitability in the brain induced by inflammation resulting from glial cell immune...explore the effectiveness of glial cell (neuroimmune) attenuation in preventing or limiting epileptogenesis (development of epilepsy) in this rapidly...with biomarker analysis in the pilocarpine model and looking at the effect of glial cell suppressant MN166 following SE on epileptogenesis (indexed by

The ubiquitin proteasome system in glia and its role in neurodegenerative diseases

PubMed Central

Jansen, Anne H. P.; Reits, Eric A. J.; Hol, Elly M.

2014-01-01

The ubiquitin proteasome system (UPS) is crucial for intracellular protein homeostasis and for degradation of aberrant and damaged proteins. The accumulation of ubiquitinated proteins is a hallmark of many neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer’s, Parkinson’s, and Huntington’s disease, leading to the hypothesis that proteasomal impairment is contributing to these diseases. So far, most research related to the UPS in neurodegenerative diseases has been focused on neurons, while glial cells have been largely disregarded in this respect. However, glial cells are essential for proper neuronal function and adopt a reactive phenotype in neurodegenerative diseases, thereby contributing to an inflammatory response. This process is called reactive gliosis, which in turn affects UPS function in glial cells. In many neurodegenerative diseases, mostly neurons show accumulation and aggregation of ubiquitinated proteins, suggesting that glial cells may be better equipped to maintain proper protein homeostasis. During an inflammatory reaction, the immunoproteasome is induced in glia, which may contribute to a more efficient degradation of disease-related proteins. Here we review the role of the UPS in glial cells in various neurodegenerative diseases, and we discuss how studying glial cell function might provide essential information in unraveling mechanisms of neurodegenerative diseases. PMID:25152710

Neuron-Glia Adhesion is Inhibited by Antibodies to Neural Determinants

NASA Astrophysics Data System (ADS)

Grumet, M.; Rutishauser, U.; Edelman, G. M.

1983-10-01

Suspensions of embryonic chick neuronal cells adhered to monolayers of glial cells, but few neurons bound to control monolayers of fibroblastic cells from meninges or skin. Neuronal cell-glial cell adhesion was inhibited by prior incubation of the neurons with Fab' fragments of antibodies to neuronal membranes. In contrast, antibodies to the neural cell adhesion molecule (N-CAM) did not inhibit the binding. These results suggest that a specific adhesive mechanism between neurons and glial cells exists and that it is mediated by CAM's that differ from those so far identified.

Perineurial Glial Plasticity and the Role of TGF-β in the Development of the Blood-Nerve Barrier.

PubMed

Morris, Angela D; Lewis, Gwendolyn M; Kucenas, Sarah

2017-05-03

Precisely orchestrated interactions between spinal motor axons and their ensheathing glia are vital for forming and maintaining functional spinal motor nerves. Following perturbations to peripheral myelinating glial cells, centrally derived oligodendrocyte progenitor cells (OPCs) ectopically exit the spinal cord and myelinate peripheral nerves in myelin with CNS characteristics. However, whether remaining peripheral ensheathing glia, such as perineurial glia, properly encase the motor nerve despite this change in glial cell and myelin composition, remains unknown. Using zebrafish mutants in which OPCs migrate out of the spinal cord and myelinate peripheral motor axons, we assayed perineurial glial development, maturation, and response to injury. Surprisingly, in the presence of OPCs, perineurial glia exited the CNS normally. However, aspects of their development, response to injury, and function were altered compared with wildtype larvae. In an effort to better understand the plasticity of perineurial glia in response to myelin perturbations, we identified transforming growth factor-β1 as a partial mediator of perineurial glial development. Together, these results demonstrate the incredible plasticity of perineurial glia in the presence of myelin perturbations. SIGNIFICANCE STATEMENT Peripheral neuropathies can result from damage or dysregulation of the insulating myelin sheath surrounding spinal motor axons, causing pain, inefficient nerve conduction, and the ectopic migration of oligodendrocyte progenitor cells (OPCs), the resident myelinating glial cell of the CNS, into the periphery. How perineurial glia, the ensheathing cells that form the protective blood-nerve barrier, are impacted by this myelin composition change is unknown. Here, we report that certain aspects of perineurial glial development and injury responses are mostly unaffected in the presence of ectopic OPCs. However, perineurial glial function is disrupted along nerves containing centrally derived myelin, demonstrating that, although perineurial glial cells display plasticity despite myelin perturbations, the blood-nerve barrier is compromised in the presence of ectopic OPCs. Copyright © 2017 the authors 0270-6474/17/374790-18$15.00/0.

Investigation of tissue cysts in the retina in a mouse model of ocular toxoplasmosis: distribution and interaction with glial cells.

PubMed

Song, Hyun Beom; Jung, Bong-Kwang; Kim, Jin Hyoung; Lee, Young-Ha; Choi, Min-Ho; Kim, Jeong Hun

2018-06-02

The conversion of tachyzoites into bradyzoites is a way for Toxoplasma gondii to establish a chronic and asymptomatic infection and achieve lifelong persistence in the host. The bradyzoites form tissue cysts in the retina, but not much is known about the horizontal distribution of the cysts or their interactions with glial cells in the retina. A chronic ocular toxoplasmosis model was induced by per oral administration of T. gondii Me49 strain cysts to BALB/c mice. Two months after the infection, retinas were flat-mounted and immunostained to detect cysts, ganglion cells, Müller cells, astrocytes, and microglial cells, followed by observation under fluorescence and confocal microscope. The horizontal distribution showed a rather clustered pattern, but the clusters were not restricted to certain location of the retina. Axial distribution was confined to the inner retina, mostly in ganglion cell layer or the inner plexiform layer. Both ganglion cells, a type of retinal neurons, and Müller cells, predominant retinal glial cells, could harbor cysts. The cysts were spatially separated from astrocytes, the most abundant glial cells in the ganglion cell layer, while close spatial distribution of microglial cells was observed in two thirds of retinal cysts. In this study, we demonstrated that the retinal cysts were not evenly distributed horizontally and were confined to the inner retina axially. Both neurons and one type of glial cells could harbor cysts, and topographic analysis of other glial cells suggests role of microglial cells in chronic ocular toxoplasmosis.

Targeting Microglia to Prevent Post-Traumatic Epilepsy

DTIC Science & Technology

2014-07-01

and the long-term effects of nigral lipopolysaccharide administration on dopaminergic dysfunction and glial cell activation. Eur J Neurosci 22 :317...LFPI). Our focus is on attenuating damaging effects of hyperexcitability in the brain induced by inflammation resulting from glial cell immune responses...biomarker analysis in the pilocarpine model and looking at the effect of glial cell suppressant MN166 following SE on epileptogenesis (indexed by seizures

Engraftment of enteric neural progenitor cells into the injured adult brain.

PubMed

Belkind-Gerson, Jaime; Hotta, Ryo; Whalen, Michael; Nayyar, Naema; Nagy, Nandor; Cheng, Lily; Zuckerman, Aaron; Goldstein, Allan M; Dietrich, Jorg

2016-01-25

A major area of unmet need is the development of strategies to restore neuronal network systems and to recover brain function in patients with neurological disease. The use of cell-based therapies remains an attractive approach, but its application has been challenging due to the lack of suitable cell sources, ethical concerns, and immune-mediated tissue rejection. We propose an innovative approach that utilizes gut-derived neural tissue for cell-based therapies following focal or diffuse central nervous system injury. Enteric neuronal stem and progenitor cells, able to differentiate into neuronal and glial lineages, were isolated from the postnatal enteric nervous system and propagated in vitro. Gut-derived neural progenitors, genetically engineered to express fluorescent proteins, were transplanted into the injured brain of adult mice. Using different models of brain injury in combination with either local or systemic cell delivery, we show that transplanted enteric neuronal progenitor cells survive, proliferate, and differentiate into neuronal and glial lineages in vivo. Moreover, transplanted cells migrate extensively along neuronal pathways and appear to modulate the local microenvironment to stimulate endogenous neurogenesis. Our findings suggest that enteric nervous system derived cells represent a potential source for tissue regeneration in the central nervous system. Further studies are needed to validate these findings and to explore whether autologous gut-derived cell transplantation into the injured brain can result in functional neurologic recovery.

Microarray analysis of glial cells resistant to JCV infection suggests a correlation between viral infection and inflammatory cytokine gene expression

PubMed Central

Manley, Kate; Gee, Gretchen V; Simkevich, Carl P; Sedivy, John M; Atwood, Walter J

2007-01-01

The human polyomavirus, JCV, has a highly restricted tropism and primarily infects glial cells. The mechanisms restricting infection of cells by JCV are poorly understood. Previously we developed and described a glial cell line that was resistant to JCV infection with the aim of using these cells to identify factors that determine JCV tropism. Gene expression profiling of susceptible and resistant glial cells revealed a direct correlation between the expression of inflammatory cytokines and susceptibility to JCV infection. This correlation manifested at the level of viral gene transcription. Previous studies have suggested a link between an increase in cytokine gene expression in HIV patients and the development of PML and these data support this hypothesis. PMID:17555786

dMyc is required in retinal progenitors to prevent JNK-mediated retinal glial activation

PubMed Central

Correia, Andreia; Santos, Marília A.; Relvas, João B.; Pereira, Paulo S.

2017-01-01

In the nervous system, glial cells provide crucial insulation and trophic support to neurons and are important for neuronal survival. In reaction to a wide variety of insults, glial cells respond with changes in cell morphology and metabolism to allow repair. Additionally, these cells can acquire migratory and proliferative potential. In particular, after axonal damage or pruning the clearance of axonal debris by glial cells is key for a healthy nervous system. Thus, bidirectional neuron-glial interactions are crucial in development, but little is known about the cellular sensors and signalling pathways involved. In here, we show that decreased cellular fitness in retinal progenitors caused by reduced Drosophila Myc expression triggers non cell-autonomous activation of retinal glia proliferation and overmigration. Glia migration occurs beyond its normal limit near the boundary between differentiated photoreceptors and precursor cells, extending into the progenitor domain. This overmigration is stimulated by JNK activation (and the function of its target Mmp1), while proliferative responses are mediated by Dpp/TGF-β signalling activation. PMID:28267791

Effect of NDP-α-MSH on PPAR-γ and –β Expression and Anti-Inflammatory Cytokine Release in Rat Astrocytes and Microglia

PubMed Central

Carniglia, Lila; Durand, Daniela; Caruso, Carla; Lasaga, Mercedes

2013-01-01

Brain inflammation plays a central role in numerous brain pathologies. Microglia and astrocytes are the main effector cells that become activated when an inflammatory process takes place within the central nervous system. α-melanocyte-stimulating hormone (α-MSH) is a neuropeptide with proven anti-inflammatory properties. It binds with highest affinity to the melanocortin receptor 4 (MC4R), which is present in astrocytes and upon activation triggers anti-inflammatory pathways. The aim of this research was to identify anti-inflammatory mediators that may participate in the immunomodulatory effects of melanocortins in glial cells. Since peroxisome proliferator-activated receptors (PPARs) have recently been implicated in the modulation of inflammation, we investigated the effect of an α-MSH analog, [Nle4, D-Phe7]-α-MSH (NDP-α-MSH), on PPAR-β and PPAR-γ gene and protein expression in rat primary astrocytes and microglia. We initially demonstrated that rat primary microglia express MC4R and showed that treatment with NDP-α-MSH increases PPAR-γ protein levels and strongly decreases PPAR-β levels in both astrocytes and microglia. We also showed that extracellular signal-regulated kinase 1/2 (ERK1/2)–mediated signaling is partially involved in these effects in a cell-specific fashion. Finally, we showed that NDP-α-MSH stimulates the release of the anti-inflammatory cytokines IL-10 and TGF-β from microglia and astrocytes, respectively. The presented data suggest a role for IL-10 and TGF-β in the protective action of melanocortins and a connection between MC4R pathway and that of the nuclear receptor PPAR-γ. This is the first report providing evidence that MC4R is expressed in rat primary microglia and that melanocortins modulate PPAR levels in glial cells. Our findings provide new insights into the mechanisms underlying the activation of glial MC4R and open perspectives for new therapeutic strategies for the treatment of inflammation-mediated brain diseases. PMID:23468969

An electrically resistive sheet of glial cells for amplifying signals of neuronal extracellular recordings

PubMed Central

Matsumura, R.; Yamamoto, H.; Niwano, M.; Hirano-Iwata, A.

2016-01-01

Electrical signals of neuronal cells can be recorded non-invasively and with a high degree of temporal resolution using multielectrode arrays (MEAs). However, signals that are recorded with these devices are small, usually 0.01%–0.1% of intracellular recordings. Here, we show that the amplitude of neuronal signals recorded with MEA devices can be amplified by covering neuronal networks with an electrically resistive sheet. The resistive sheet used in this study is a monolayer of glial cells, supportive cells in the brain. The glial cells were grown on a collagen-gel film that is permeable to oxygen and other nutrients. The impedance of the glial sheet was measured by electrochemical impedance spectroscopy, and equivalent circuit simulations were performed to theoretically investigate the effect of covering the neurons with such a resistive sheet. Finally, the effect of the resistive glial sheet was confirmed experimentally, showing a 6-fold increase in neuronal signals. This technique feasibly amplifies signals of MEA recordings. PMID:27703279

Glial hemichannels and their involvement in aging and neurodegenerative diseases.

PubMed

Orellana, Juan A; von Bernhardi, Rommy; Giaume, Christian; Sáez, Juan C

2012-01-26

During the last two decades, it became increasingly evident that glial cells accomplish a more important role in brain function than previously thought. Glial cells express pannexins and connexins, which are member subunits of two protein families that form membrane channels termed hemichannels. These channels communicate intra- and extracellular compartments and allow the release of autocrine/paracrine signaling molecules [e.g., adenosine triphosphate (ATP), glutamate, nicotinamide adenine dinucleotide, and prostaglandin E2] to the extracellular milieu, as well as the uptake of small molecules (e.g., glucose). An increasing body of evidence has situated glial hemichannels as potential regulators of the beginning and maintenance of homeostatic imbalances observed in diverse brain diseases. Here, we review and discuss the current evidence about the possible role of glial hemichannels on neurodegenerative diseases. A subthreshold pathological threatening condition leads to microglial activation, which keeps active defense and restores the normal function of the central nervous system. However, if the stimulus is deleterious, microglial cells and the endothelium become overactivated, both releasing bioactive molecules (e.g., glutamate, cytokines, prostaglandins, and ATP), which increase the activity of glial hemichannels, reducing the astroglial neuroprotective functions, and further reducing neuronal viability. Because ATP and glutamate are released via glial hemichannels in neurodegenerative conditions, it is expected that they contribute to neurotoxicity. More importantly, toxic molecules released via glial hemichannels could increase the Ca2+ entry in neurons also via neuronal hemichannels, leading to neuronal death. Therefore, blockade of hemichannels expressed by glial cells and/or neurons during neuroinflammation might prevent neurodegeneration.

GnRH Episodic Secretion Is Altered by Pharmacological Blockade of Gap Junctions: Possible Involvement of Glial Cells.

PubMed

Pinet-Charvet, Caroline; Geller, Sarah; Desroziers, Elodie; Ottogalli, Monique; Lomet, Didier; Georgelin, Christine; Tillet, Yves; Franceschini, Isabelle; Vaudin, Pascal; Duittoz, Anne

2016-01-01

Episodic release of GnRH is essential for reproductive function. In vitro studies have established that this episodic release is an endogenous property of GnRH neurons and that GnRH secretory pulses are associated with synchronization of GnRH neuron activity. The cellular mechanisms by which GnRH neurons synchronize remain largely unknown. There is no clear evidence of physical coupling of GnRH neurons through gap junctions to explain episodic synchronization. However, coupling of glial cells through gap junctions has been shown to regulate neuron activity in their microenvironment. The present study investigated whether glial cell communication through gap junctions plays a role in GnRH neuron activity and secretion in the mouse. Our findings show that Glial Fibrillary Acidic Protein-expressing glial cells located in the median eminence in close vicinity to GnRH fibers expressed Gja1 encoding connexin-43. To study the impact of glial-gap junction coupling on GnRH neuron activity, an in vitro model of primary cultures from mouse embryo nasal placodes was used. In this model, GnRH neurons possess a glial microenvironment and were able to release GnRH in an episodic manner. Our findings show that in vitro glial cells forming the microenvironment of GnRH neurons expressed connexin-43 and displayed functional gap junctions. Pharmacological blockade of the gap junctions with 50 μM 18-α-glycyrrhetinic acid decreased GnRH secretion by reducing pulse frequency and amplitude, suppressed neuronal synchronization and drastically reduced spontaneous electrical activity, all these effects were reversed upon 18-α-glycyrrhetinic acid washout.

Glial kon/NG2 gene network for central nervous system repair.

PubMed

Losada-Perez, Maria; Harrison, Neale; Hidalgo, Alicia

2017-01-01

The glial regenerative response to central nervous system (CNS) injury, although limited, can be harnessed to promote regeneration and repair. Injury provokes the proliferation of ensheathing glial cells, which can differentiate to remyelinate axons, and partially restore function. This response is evolutionarily conserved, strongly implying an underlying genetic mechanism. In mammals, it is elicited by NG2 glia, but most often newly generated cells fail to differentiate. Thus an important goal had been to find out how to promote glial differentiation following the proliferative response. A gene network involving Notch and prospero (pros) controls the balance between glial proliferation and differentiation in flies and mice, and promotes CNS repair at least in fruit-flies. A key missing link had been how to relate the function of NG2 to this gene network. Recent findings by Losada-Perez et al., published in JCB, demonstrated that the Drosophila NG2 homologue kon-tiki (kon) is functionally linked to Notch and pros in glia. By engaging in two feedback loops with Notch and Pros, in response to injury, Kon can regulate both glial cell number and glial shape homeostasis, essential for repair. Drosophila offers powerful genetics to unravel the control of stem and progenitor cells for regeneration and repair.

Scavenger Receptor-A deficiency impairs immune response of microglia and astrocytes potentiating Alzheimer's disease pathophysiology.

PubMed

Cornejo, Francisca; Vruwink, Marianne; Metz, Claudia; Muñoz, Paola; Salgado, Nicole; Poblete, Joaquín; Andrés, María Estela; Eugenín, Jaime; von Bernhardi, Rommy

2018-03-01

Late onset Alzheimer disease's (LOAD) main risk factor is aging. Although it is not well known which age-related factors are involved in its development, evidence points out to the involvement of an impaired amyloid-β (Aβ) clearance in the aged brain among possible causes. Glial cells are the main scavengers of the brain, where Scavenger Receptor class A (SR-A) emerges as a relevant player in AD because of its participation in Aβ uptake and in the modulation of glial cell inflammatory response. Here, we show that SR-A expression is reduced in the hippocampus of aged animals and APP/PS1 mice. Given that Aβ deposition increases in the aging brain, we generated a triple transgenic mouse, which accumulates Aβ and is knockout for SR-A (APP/PS1/SR-A -/- ) to evaluate Aβ accumulation and the inflammatory outcome of SR-A depletion in the aged brain. The lifespan of APP/PS1/SR-A -/- mice was greatly reduced, accompanied by a 3-fold increase in plasmatic pro-inflammatory cytokines, and reduced performance in a working memory behavioral assessment. Microglia and astrocytes lacking SR-A displayed impaired oxidative response and nitric oxide production, produced up to 7-fold more pro-inflammatory cytokines and showed a 12-fold reduction in anti-inflammatory cytokines release, with conspicuous changes in lipopolysaccharide-induced glial activation. Isolated microglia from young and adult mice lacking SR-A showed a 50% reduction in phagocytic activity. Our results indicate that reduced expression of SR-A can deregulate glial inflammatory response and potentiate Aβ accumulation, two mechanisms that could contribute to AD progression. Copyright © 2017 Elsevier Inc. All rights reserved.

Supradural inflammatory soup in awake and freely moving rats induces facial allodynia that is blocked by putative immune modulators.

PubMed

Wieseler, Julie; Ellis, Amanda; McFadden, Andrew; Stone, Kendra; Brown, Kimberley; Cady, Sara; Bastos, Leandro F; Sprunger, David; Rezvani, Niloofar; Johnson, Kirk; Rice, Kenner C; Maier, Steven F; Watkins, Linda R

2017-06-01

Facial allodynia is a migraine symptom that is generally considered to represent a pivotal point in migraine progression. Treatment before development of facial allodynia tends to be more successful than treatment afterwards. As such, understanding the underlying mechanisms of facial allodynia may lead to a better understanding of the mechanisms underlying migraine. Migraine facial allodynia is modeled by applying inflammatory soup (histamine, bradykinin, serotonin, prostaglandin E2) over the dura. Whether glial and/or immune activation contributes to such pain is unknown. Here we tested if trigeminal nucleus caudalis (Sp5C) glial and/or immune cells are activated following supradural inflammatory soup, and if putative glial/immune inhibitors suppress the consequent facial allodynia. Inflammatory soup was administered via bilateral indwelling supradural catheters in freely moving rats, inducing robust and reliable facial allodynia. Gene expression for microglial/macrophage activation markers, interleukin-1β, and tumor necrosis factor-α increased following inflammatory soup along with robust expression of facial allodynia. This provided the basis for pursuing studies of the behavioral effects of 3 diverse immunomodulatory drugs on facial allodynia. Pretreatment with either of two compounds broadly used as putative glial/immune inhibitors (minocycline, ibudilast) prevented the development of facial allodynia, as did treatment after supradural inflammatory soup but prior to the expression of facial allodynia. Lastly, the toll-like receptor 4 (TLR4) antagonist (+)-naltrexone likewise blocked development of facial allodynia after supradural inflammatory soup. Taken together, these exploratory data support that activated glia and/or immune cells may drive the development of facial allodynia in response to supradural inflammatory soup in unanesthetized male rats. Copyright © 2017 Elsevier B.V. All rights reserved.

Long term imaging of living brain cancer cells

NASA Astrophysics Data System (ADS)

Farias, Patricia M. A.; Galembeck, André; Milani, Raquel; Andrade, Arnaldo C. D. S.; Stingl, Andreas

2018-02-01

QDs synthesized in aqueous medium and functionalized with polyethylene glycol were used as fluorescent probes. They label and monitor living healthy and cancer brain glial cells in culture. Physical-chemical characterization was performed. Toxicological studies were performed by in vivo short and long-term inhalation in animal models. Healthy and cancer glial living cells were incubated in culture media with highly controlled QDs. Specific features of glial cancer cells were enhanced by QD labelling. Cytoplasmic labelling pattern was clearly distinct for healthy and cancer cells. Labelled cells kept their normal activity for same period as non-labelled control samples.

Complex and differential glial responses in Alzheimer's disease and ageing.

PubMed

Rodríguez, José J; Butt, Arthur M; Gardenal, Emanuela; Parpura, Vladimir; Verkhratsky, Alexei

2016-01-01

Glial cells and their association with neurones are fundamental for brain function. The emergence of complex neurone-glial networks assures rapid information transfer, creating a sophisticated circuitry where both types of neural cells work in concert, serving different activities. All glial cells, represented by astrocytes, oligodendrocytes, microglia and NG2-glia, are essential for brain homeostasis and defence. Thus, glia are key not only for normal central nervous system (CNS) function, but also to its dysfunction, being directly associated with all forms of neuropathological processes. Therefore, the progression and outcome of neurological and neurodegenerative diseases depend on glial reactions. In this review, we provide a concise account of recent data obtained from both human material and animal models demonstrating the pathological involvement of glia in neurodegenerative processes, including Alzheimer's disease (AD), as well as physiological ageing.

Gastrin Induces Nuclear Export and Proteasome Degradation of Menin in Enteric Glial Cells.

PubMed

Sundaresan, Sinju; Meininger, Cameron A; Kang, Anthony J; Photenhauer, Amanda L; Hayes, Michael M; Sahoo, Nirakar; Grembecka, Jolanta; Cierpicki, Tomasz; Ding, Lin; Giordano, Thomas J; Else, Tobias; Madrigal, David J; Low, Malcolm J; Campbell, Fiona; Baker, Ann-Marie; Xu, Haoxing; Wright, Nicholas A; Merchant, Juanita L

2017-12-01

The multiple endocrine neoplasia, type 1 (MEN1) locus encodes the nuclear protein and tumor suppressor menin. MEN1 mutations frequently cause neuroendocrine tumors such as gastrinomas, characterized by their predominant duodenal location and local metastasis at time of diagnosis. Diffuse gastrin cell hyperplasia precedes the appearance of MEN1 gastrinomas, which develop within submucosal Brunner's glands. We investigated how menin regulates expression of the gastrin gene and induces generation of submucosal gastrin-expressing cell hyperplasia. Primary enteric glial cultures were generated from the VillinCre:Men1 FL/FL :Sst -/- mice or C57BL/6 mice (controls), with or without inhibition of gastric acid by omeprazole. Primary enteric glial cells from C57BL/6 mice were incubated with gastrin and separated into nuclear and cytoplasmic fractions. Cells were incubated with forskolin and H89 to activate or inhibit protein kinase A (a family of enzymes whose activity depends on cellular levels of cyclic AMP). Gastrin was measured in blood, tissue, and cell cultures using an ELISA. Immunoprecipitation with menin or ubiquitin was used to demonstrate post-translational modification of menin. Primary glial cells were incubated with leptomycin b and MG132 to block nuclear export and proteasome activity, respectively. We obtained human duodenal, lymph node, and pancreatic gastrinoma samples, collected from patients who underwent surgery from 1996 through 2007 in the United States or the United Kingdom. Enteric glial cells that stained positive for glial fibrillary acidic protein (GFAP+) expressed gastrin de novo through a mechanism that required PKA. Gastrin-induced nuclear export of menin via cholecystokinin B receptor (CCKBR)-mediated activation of PKA. Once exported from the nucleus, menin was ubiquitinated and degraded by the proteasome. GFAP and other markers of enteric glial cells (eg, p75 and S100B), colocalized with gastrin in human duodenal gastrinomas. MEN1-associated gastrinomas, which develop in the submucosa, might arise from enteric glial cells through hormone-dependent PKA signaling. This pathway disrupts nuclear menin function, leading to hypergastrinemia and associated sequelae. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

[New concepts on the role of cytokines in the central nervous system].

PubMed

Jacque, C; Tchélingérian, J L

1994-11-01

Initially described as modulatory molecules in the peripheral immune system and during haematopoiesis, several cytokines also play a role in the brain. Their synthesis in the central nervous system (CNS) is not due solely to glial cell activation or invading immune cells. On the one hand, several functions of central neurons are modulated by cytokines such as IL-1, TNF alpha, IL-2 and IL-6. Thus, IL-1 and TNF alpha modulate the synthesis of several neuromediators and modify ion influxes. IL-2 regulates the effects of central dopaminergic neurons on cholinergic, noradrenergic, serotoninergic and glutamatergic functions. On the other hand, neurons have recently been shown to be able to synthesize some of these cytokines under specific traumatic conditions. For example, a lesion to the hippocampus induces neuronal synthesis of IL-1 alpha and TNF alpha. This induction through neuronal circuits may operate at a distance in contrast to the glial reaction operating only locally. The recent demonstration of the expression by central neurons of receptors specific for these cytokines support a potentially crucial role for these molecules in brain function. Some data emerge in the literature demonstrating a potent expression of cytokines in the central nervous system in numerous pathological situations. Then, it appears that, at the interface between nervous and immune systems, cytokines may bear a pivotal role in the development of specific symptoms in neuroimmune diseases.

Sonic Hedgehog modulates EGFR dependent proliferation of neural stem cells during late mouse embryogenesis through EGFR transactivation

PubMed Central

Reinchisi, Gisela; Parada, Margarita; Lois, Pablo; Oyanadel, Claudia; Shaughnessy, Ronan; Gonzalez, Alfonso; Palma, Verónica

2013-01-01

Sonic Hedgehog (Shh/GLI) and EGFR signaling pathways modulate Neural Stem Cell (NSC) proliferation. How these signals cooperate is therefore critical for understanding normal brain development and function. Here we report a novel acute effect of Shh signaling on EGFR function. We show that during late neocortex development, Shh mediates the activation of the ERK1/2 signaling pathway in Radial Glial cells (RGC) through EGFR transactivation. This process is dependent on metalloprotease activity and accounts for almost 50% of the EGFR-dependent mitogenic response of late NSCs. Furthermore, in HeLa cancer cells, a well-known model for studying the EGFR receptor function, Shh also induces cell proliferation involving EGFR activation, as reflected by EGFR internalization and ERK1/2 phosphorylation. These findings may have important implications for understanding the mechanisms that regulate NSC proliferation during neurogenesis and may lead to novel approaches to the treatment of tumors. PMID:24133411

Flow Cytometric Detection of PrPSc in Neurons and Glial Cells from Prion-Infected Mouse Brains.

PubMed

Yamasaki, Takeshi; Suzuki, Akio; Hasebe, Rie; Horiuchi, Motohiro

2018-01-01

In prion diseases, an abnormal isoform of prion protein (PrP Sc ) accumulates in neurons, astrocytes, and microglia in the brains of animals affected by prions. Detailed analyses of PrP Sc -positive neurons and glial cells are required to clarify their pathophysiological roles in the disease. Here, we report a novel method for the detection of PrP Sc in neurons and glial cells from the brains of prion-infected mice by flow cytometry using PrP Sc -specific staining with monoclonal antibody (MAb) 132. The combination of PrP Sc staining and immunolabeling of neural cell markers clearly distinguished neurons, astrocytes, and microglia that were positive for PrP Sc from those that were PrP Sc negative. The flow cytometric analysis of PrP Sc revealed the appearance of PrP Sc -positive neurons, astrocytes, and microglia at 60 days after intracerebral prion inoculation, suggesting the presence of PrP Sc in the glial cells, as well as in neurons, from an early stage of infection. Moreover, the kinetic analysis of PrP Sc revealed a continuous increase in the proportion of PrP Sc -positive cells for all cell types with disease progression. Finally, we applied this method to isolate neurons, astrocytes, and microglia positive for PrP Sc from a prion-infected mouse brain by florescence-activated cell sorting. The method described here enables comprehensive analyses specific to PrP Sc -positive neurons, astrocytes, and microglia that will contribute to the understanding of the pathophysiological roles of neurons and glial cells in PrP Sc -associated pathogenesis. IMPORTANCE Although formation of PrP Sc in neurons is associated closely with neurodegeneration in prion diseases, the mechanism of neurodegeneration is not understood completely. On the other hand, recent studies proposed the important roles of glial cells in PrP Sc -associated pathogenesis, such as the intracerebral spread of PrP Sc and clearance of PrP Sc from the brain. Despite the great need for detailed analyses of PrP Sc -positive neurons and glial cells, methods available for cell type-specific analysis of PrP Sc have been limited thus far to microscopic observations. Here, we have established a novel high-throughput method for flow cytometric detection of PrP Sc in cells with more accurate quantitative performance. By applying this method, we succeeded in isolating PrP Sc -positive cells from the prion-infected mouse brains via fluorescence-activated cell sorting. This allows us to perform further detailed analysis specific to PrP Sc -positive neurons and glial cells for the clarification of pathological changes in neurons and pathophysiological roles of glial cells. Copyright © 2017 American Society for Microbiology.

Glutamate-dependent transcriptional regulation in bergmann glia cells: involvement of p38 MAP kinase.

PubMed

Zepeda, Rossana C; Barrera, Iliana; Castelán, Francisco; Soto-Cid, Abraham; Hernández-Kelly, Luisa C; López-Bayghen, Esther; Ortega, Arturo

2008-07-01

Glutamate (Glu) is the major excitatory neurotransmitter in the Central Nervous System (CNS). Ionotropic and metabotropic glutamate receptors (GluRs) are present in neurons and glial cells and are involved in gene expression regulation. Mitogen-activated proteins kinases (MAPK) are critical for all the membrane to nuclei signaling pathways described so far. In cerebellar Bergmann glial cells, glutamate-dependent transcriptional regulation is partially dependent on p42/44 MAPK activity. Another member of this kinase family, p38 MAPK is activated by non-mitogenic stimuli through its Thr180/Tyr182 phosphorylation and phosphorylates cytoplasmic and nuclear protein targets involved in translational and transcriptional events. Taking into consideration that the role of p38MAPK in glial cells is not well understood, we demonstrate here that glutamate increases p38 MAPK phosphorylation in a time and dose dependent manner in cultured chick cerebellar Bergmann glial cells (BGC). Moreover, p38 MAPK is involved in the glutamate-induced transcriptional activation in these cells. Ionotropic as well as metabotropic glutamate receptors participate in p38 MAPK activation. The present findings demonstrate the involvement of p38 MAPK in glutamate-dependent gene expression regulation in glial cells.

The Impact of Oxidative Stress Factors on the Viability, Senescence, and Methylation Status of Olfactory Bulb-Derived Glial Cells Isolated from Human Cadaver Donors.

PubMed

Marycz, Krzysztof; Kornicka, Katarzyna; Grzesiak, Jakub; Tomaszewski, Krzysztof A; Szarek, Dariusz; Kopacz, Paweł

2017-01-01

The olfactory bulb (OB) is a unique structure in the central nervous system that retains the ability to create new neuronal connections. Glial cells isolated from the OB have been recently considered as a novel and promising tool to establish an effective therapy for central nervous system injuries. Due to the hindered access to autologous tissue for cell isolation, an allogeneic source of tissues obtained postmortem has been proposed. In this study, we focused on the morphological and molecular characteristics of human OB-derived glial cells isolated postmortem, at different time points after a donor's death. We evaluated the proliferative activity of the isolated cells, and investigated the ultrastructure of the mitochondria, the accumulation of intracellular reactive oxygen species, and the activity of superoxide dismutase. The data obtained clearly indicate that the duration of ischemia is crucial for the viability/senescence rate of OB-derived glial cells. The OB can be isolated during autopsy and still stand as a source of viable glial cells, but ischemia duration is a major factor limiting its potential usefulness in therapies. © 2017 S. Karger AG, Basel.

Cloning and characteristics of fish glial fibrillary acidic protein: implications for optic nerve regeneration.

PubMed

Cohen, I; Shani, Y; Schwartz, M

1993-08-15

Mammalian central nervous system neurons do not regenerate after axonal injury, unlike their counterparts in fish and amphibians. After axonal injury, glial cells in mammals do not support regrowth of axons, while in fish they support the regeneration process. Controversy exists as to whether or not the intact fish optic nerve expresses glial fibrillary acidic protein, a well-known marker for mature astrocytes, and thus whether its astrocytes differ in this respect from those of the brain and spinal cord, as well as from optic nerve astrocytes of other species. In an attempt to resolve this question we cloned fish glial fibrillary acidic protein. Two different complementary DNA clones were isolated from a carp brain complementary DNA library, each encoding a different form of glial fibrillary acidic protein apparently originating from different genes. Monospecific polyclonal antibodies were raised against a peptide synthesized according to the predicted amino acid sequence, and used to identify and localize the fish glial fibrillary acidic protein. Two glial fibrillary acidic proteins (of 49 kDa and 51 kDa) were identified by the antibodies in all tested fish central nervous system tissues. The antibodies were then used to examine glial fibrillary acidic protein immunoreactivity in sections taken from uninjured and injured optic nerves of goldfish. Injury was followed by an elevation in glial fibrillary acidic protein immunoreactivity along the whole length of the nerve, except at the site of the injury, where--as in the case of vimentin--no immunoreactivity was detectable. However, in contrast to vimentin-positive glial cells, which repopulate the site of the injury soon after the optic nerve is injured, glial fibrillary acidic protein-positive glial cells remained outside the injury site for as long as 6 weeks after the injury. Despite the injury-induced changes in glial fibrillary acidic protein immunoreactivity, no change was observed in the level of transcript encoding glial fibrillary acidic protein after injury, while there was an increase in the amount of glial fibrillary acidic protein associated with the cytoskeleton and a reduction in the soluble form. These results suggest that the injury-induced changes in immunoreactivity on sections involve changes not in transcription or translation of glial fibrillary acidic protein, but in glial fibrillary acidic protein compartmentalization.

Imaging of glial cell morphology, SOD1 distribution and elemental composition in the brainstem and hippocampus of the ALS hSOD1G93A rat.

PubMed

Stamenković, Stefan; Dučić, Tanja; Stamenković, Vera; Kranz, Alexander; Andjus, Pavle R

2017-08-15

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting motor and cognitive domains of the CNS. Mutations in the Cu,Zn-superoxide dismutase (SOD1) cause 20% of familial ALS and provoke formation of intracellular aggregates and copper and zinc unbinding, leading to glial activation and neurodegeneration. Therefore, we investigated glial cell morphology, intracellular SOD1 distribution, and elemental composition in the brainstem and hippocampus of the hSOD1 G93A transgenic rat model of ALS. Immunostaining for astrocytes, microglia and SOD1 revealed glial proliferation and progressive tissue accumulation of SOD1 in both brain regions of ALS rats starting already at the presymptomatic stage. Glial cell morphology analysis in the brainstem of ALS rats revealed astrocyte activation occurring before disease symptoms onset, followed by activation of microglia. Hippocampal ALS astrocytes exhibited an identical reactive profile, while microglial morphology was unchanged. Additionally, ALS brainstem astrocytes demonstrated progressive SOD1 accumulation in the cell body and processes, while microglial SOD1 levels were reduced and its distribution limited to distal cell processes. In the hippocampus both glial cell types exhibited SOD1 accumulation in the cell body. X-ray fluorescence imaging revealed decreased P and increased Ca, Cl, K, Ni, Cu and Zn in the brainstem, and higher levels of Cl, Ni and Cu, but lower levels of Zn in the hippocampus of symptomatic ALS rats. These results bring new insights into the glial response during disease development and progression in motor as well as in non-motor CNS structures, and indicate disturbed tissue elemental homeostasis as a prominent hallmark of disease pathology. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Intact working memory in the absence of forebrain neuronal glycine transporter 1

PubMed Central

Dubroqua, Sylvain; Serrano, Lucas; Boison, Detlev; Feldon, Joram; Gargiulo, Pascual A.; Yee, Benjamin K.

2012-01-01

Glycine transporter 1 (GlyT1) is a potential pharmacological target to ameliorate memory deficits attributable to N-methyl-d-aspartate receptor (NMDAR) hypofunction. Disruption of glycine-reuptake near excitatory synapses is expected to enhance NMDAR function by increasing glycine-B site occupancy. Genetic models with conditional GlyT1 deletion restricted to forebrain neurons have yielded several promising promnesic effects, yet its impact on working memory function remains essentially unanswered because a previous attempt had yielded un-interpretable outcomes. The present study clarified this important outstanding lacuna using a within-subject multi-paradigm approach. Here, a consistent lack of effects was convincingly demonstrated across three working memory test paradigms – the radial arm maze, the cheeseboard maze, and the water maze. These null outcomes contrasted with the phenotype of enhanced working memory performance seen in mutant mice with GlyT1 deletion extended to cortical/hippocampal glial cells. It follows that glial-based GlyT1 might be more closely linked to the modulation of working memory function, and raises the possibility that neuronal and glial GlyT1 may regulate cognitive functions via dissociable mechanisms. PMID:22342492

Axonal sprouting and laminin appearance after destruction of glial sheaths.

PubMed Central

Masuda-Nakagawa, L M; Muller, K J; Nicholls, J G

1993-01-01

Laminin, a large extracellular matrix molecule, is associated with axonal outgrowth during development and regeneration of the nervous system in a variety of animals. In the leech central nervous system, laminin immunoreactivity appears after axon injury in advance of the regenerating axons. Although studies of vertebrate nervous system in culture have implicated glial and Schwann cells as possible sources, the cells that deposit laminin at sites crucial for regeneration in the living animal are not known. We have made a direct test to determine whether, in the central nervous system of the leech, cells other than ensheathing glial cells can produce laminin. Ensheathing glial cells of adult leeches were ablated selectively by intracellular injection of a protease. As a result, leech laminin accumulated within 10 days in regions of the central nervous system where it is not normally found, and undamaged, intact axons began to sprout extensively. In normal leeches laminin immunoreactivity is situated only in the basement membrane that surrounds the central nervous system, whereas after ablation of ensheathing glia it appeared in spaces through which neurons grew. Within days of ablation of the glial cell, small mobile phagocytes, or microglia, accumulated in the spaces formerly occupied by the glial cell. Microglia were concentrated at precisely the sites of new laminin appearance and axon sprouting. These results suggest that in the animal, as in culture, leech laminin promotes sprouting and that microglia may be responsible for its appearance. Images Fig. 1 Fig. 2 Fig. 3 PMID:8506343

A New Outlook on Mental Illnesses: Glial Involvement Beyond the Glue.

PubMed

Elsayed, Maha; Magistretti, Pierre J

2015-01-01

Mental illnesses have long been perceived as the exclusive consequence of abnormalities in neuronal functioning. Until recently, the role of glial cells in the pathophysiology of mental diseases has largely been overlooked. However recently, multiple lines of evidence suggest more diverse and significant functions of glia with behavior-altering effects. The newly ascribed roles of astrocytes, oligodendrocytes and microglia have led to their examination in brain pathology and mental illnesses. Indeed, abnormalities in glial function, structure and density have been observed in postmortem brain studies of subjects diagnosed with mental illnesses. In this review, we discuss the newly identified functions of glia and highlight the findings of glial abnormalities in psychiatric disorders. We discuss these preclinical and clinical findings implicating the involvement of glial cells in mental illnesses with the perspective that these cells may represent a new target for treatment.

A New Outlook on Mental Illnesses: Glial Involvement Beyond the Glue

PubMed Central

Elsayed, Maha; Magistretti, Pierre J.

2015-01-01

Mental illnesses have long been perceived as the exclusive consequence of abnormalities in neuronal functioning. Until recently, the role of glial cells in the pathophysiology of mental diseases has largely been overlooked. However recently, multiple lines of evidence suggest more diverse and significant functions of glia with behavior-altering effects. The newly ascribed roles of astrocytes, oligodendrocytes and microglia have led to their examination in brain pathology and mental illnesses. Indeed, abnormalities in glial function, structure and density have been observed in postmortem brain studies of subjects diagnosed with mental illnesses. In this review, we discuss the newly identified functions of glia and highlight the findings of glial abnormalities in psychiatric disorders. We discuss these preclinical and clinical findings implicating the involvement of glial cells in mental illnesses with the perspective that these cells may represent a new target for treatment. PMID:26733803

Exocytosis of ATP From Astrocytes Modulates Phasic and Tonic Inhibition in the Neocortex

PubMed Central

Rasooli-Nejad, Seyed; Andrew, Jemma; Haydon, Philip G.; Pankratov, Yuriy

2014-01-01

Communication between neuronal and glial cells is important for many brain functions. Astrocytes can modulate synaptic strength via Ca2+-stimulated release of various gliotransmitters, including glutamate and ATP. A physiological role of ATP release from astrocytes was suggested by its contribution to glial Ca2+-waves and purinergic modulation of neuronal activity and sleep homeostasis. The mechanisms underlying release of gliotransmitters remain uncertain, and exocytosis is the most intriguing and debated pathway. We investigated release of ATP from acutely dissociated cortical astrocytes using “sniff-cell” approach and demonstrated that release is vesicular in nature and can be triggered by elevation of intracellular Ca2+ via metabotropic and ionotropic receptors or direct UV-uncaging. The exocytosis of ATP from neocortical astrocytes occurred in the millisecond time scale contrasting with much slower nonvesicular release of gliotransmitters via Best1 and TREK-1 channels, reported recently in hippocampus. Furthermore, we discovered that elevation of cytosolic Ca2+ in cortical astrocytes triggered the release of ATP that directly activated quantal purinergic currents in the pyramidal neurons. The glia-driven burst of purinergic currents in neurons was followed by significant attenuation of both synaptic and tonic inhibition. The Ca2+-entry through the neuronal P2X purinoreceptors led to phosphorylation-dependent down-regulation of GABAA receptors. The negative purinergic modulation of postsynaptic GABA receptors was accompanied by small presynaptic enhancement of GABA release. Glia-driven purinergic modulation of inhibitory transmission was not observed in neurons when astrocytes expressed dn-SNARE to impair exocytosis. The astrocyte-driven purinergic currents and glia-driven modulation of GABA receptors were significantly reduced in the P2X4 KO mice. Our data provide a key evidence to support the physiological importance of exocytosis of ATP from astrocytes in the neocortex. PMID:24409095

Proteomic profiling reveals dopaminergic regulation of progenitor cell functions of goldfish radial glial cells in vitro.

PubMed

Xing, Lei; Martyniuk, Christopher J; Esau, Crystal; Da Fonte, Dillon F; Trudeau, Vance L

2016-07-20

Radial glial cells (RGCs) are stem-like cells found in the developing and adult central nervous system. They function as both a scaffold to guide neuron migration and as progenitor cells that support neurogenesis. Our previous study revealed a close anatomical relationship between dopamine neurons and RGCs in the telencephalon of female goldfish. In this study, label-free proteomics was used to identify the proteins in a primary RGC culture and to determine the proteome response to the selective dopamine D1 receptor agonist SKF 38393 (10μM), in order to better understand dopaminergic regulation of RGCs. A total of 689 unique proteins were identified in the RGCs and these were classified into biological and pathological pathways. Proteins such as nucleolin (6.9-fold) and ependymin related protein 1 (4.9-fold) were increased in abundance while proteins triosephosphate isomerase (10-fold) and phosphoglycerate dehydrogenase (5-fold) were decreased in abundance. Pathway analysis revealed that proteins that consistently changed in abundance across biological replicates were related to small molecules such as ATP, lipids and steroids, hormones, glucose, cyclic AMP and Ca(2+). Sub-network enrichment analysis suggested that estrogen receptor signaling, among other transcription factors, is regulated by D1 receptor activation. This suggests that these signaling pathways are correlated to dopaminergic regulation of radial glial cell functions. Most proteins down-regulated by SKF 38393 were involved in cell cycle/proliferation, growth, death, and survival, which suggests that dopamine inhibits the progenitor-related processes of radial glial cells. Examples of differently expressed proteins including triosephosphate isomerase, nucleolin, phosphoglycerate dehydrogenase and capping protein (actin filament) muscle Z-line beta were validated by qPCR and western blot, which were consistent with MS/MS data in the direction of change. This is the first study to characterize the RGC proteome on a large scale in a vertebrate species. These data provide novel insight into glial protein networks that are associated with neuroendocrine function and neurogenesis in the teleost brain. While the role of radial glial cells in organizing brain structure and neurogenesis has been well studied, protein profiling experiments in this unique cell type has not been conducted. This study is the first to profile the proteome of goldfish radial glial cells in culture and to study the regulation of progenitor functions of radial glial cells by the neurotransmitter dopamine. This study provides the foundation for molecular network analysis in fish radial glial cells, and identifies cellular processes and signaling pathways in these cells with roles in neurogenesis and neuroendocrine function. Lastly, this study begins to characterize signatures and biomarkers for specific neuroendocrine and neurogenesis disruptors. Copyright © 2016 Elsevier B.V. All rights reserved.

Immunocytochemical localization of glial fibrillary acidic protein (GFAP) in the area postrema of the cat - Light and electron microscopic study

NASA Technical Reports Server (NTRS)

Damelio, F. E.; Gibbs, M. A.; Mehler, W. R.; Eng, L. F.

1985-01-01

Glial fibrillary acidic protein (GFAP) was demonstrated in the cytoplasm and processes of ependymal cells and astroglial components of the area postrema of the cat. These observations differ from the findings in the ependyma of the ventricular cavities which are consistently negative for the protein. Since some studies have suggested sensory functions of the glial cells in this emetic chemoreceptor trigger zone, a careful consideration of morphological and biochemical attributes of these cells seems appropriate.

Pathophysiological roles of P2 receptors in glial cells.

PubMed

Abbracchio, Maria P; Verderio, Claudia

2006-01-01

Extracellular nucleotides act through specific receptors on target cells: the seven ionotropic P2X and the eight G protein-coupled P2Y receptors. All these receptors are expressed by brain astroglia and microglia. In astrocytes, P2 receptors have been implicated in short-term calcium-dependent cell-cell communication. Upon mechanical stimulation or activation by other transmitters, astrocytes release ATP and respond to ATP with a propagating wave of intracellular calcium increases, allowing a homotypic astrocyte-astrocyte communication, as well as an heterotypic signalling which also involves neurons, oligodendrocytes and microglia. Astrocytic P2 receptors also mediate reactive astrogliosis, a reaction contributing to neuronal death in neurodegenerative diseases. Signalling leading to inflammatory astrogliosis involves induction of cyclo-oxygenase 2 through stimulation of ERK1,2 and of the transcriptional factors AP-1 and NF-kappaB. Microglia also express several P2 receptors linked to intracellular calcium increases. P2 receptor subtypes are differentially regulated by typical proinflammatory signals for these cells (e.g. lipopolysaccharide), suggesting specific roles in brain immune responses. Globally, these findings highlight the roles of P2 receptors in glial cell pathophysiology suggesting a contribution to neurodegenerative diseases characterized by excessive gliosis and neuro-inflammation. They also open up the possibility of modulating brain damage by ligands selectively targeting the specific P2 receptor subtypes involved in the gliotic response.

Neural stem/progenitor cell properties of glial cells in the adult mouse auditory nerve

PubMed Central

Lang, Hainan; Xing, Yazhi; Brown, LaShardai N.; Samuvel, Devadoss J.; Panganiban, Clarisse H.; Havens, Luke T.; Balasubramanian, Sundaravadivel; Wegner, Michael; Krug, Edward L.; Barth, Jeremy L.

2015-01-01

The auditory nerve is the primary conveyor of hearing information from sensory hair cells to the brain. It has been believed that loss of the auditory nerve is irreversible in the adult mammalian ear, resulting in sensorineural hearing loss. We examined the regenerative potential of the auditory nerve in a mouse model of auditory neuropathy. Following neuronal degeneration, quiescent glial cells converted to an activated state showing a decrease in nuclear chromatin condensation, altered histone deacetylase expression and up-regulation of numerous genes associated with neurogenesis or development. Neurosphere formation assays showed that adult auditory nerves contain neural stem/progenitor cells (NSPs) that were within a Sox2-positive glial population. Production of neurospheres from auditory nerve cells was stimulated by acute neuronal injury and hypoxic conditioning. These results demonstrate that a subset of glial cells in the adult auditory nerve exhibit several characteristics of NSPs and are therefore potential targets for promoting auditory nerve regeneration. PMID:26307538

Unusual Case of Combined Gliomeningeal Heterotopia on the Nose of an Infant.

PubMed

Schauer, Anna; Harvey, Nathan T; Vijayasekaran, Shyan; Wood, Benjamin A

2017-10-24

Nasal glial heterotopia ("nasal glioma") and cutaneous heterotopic meningeal nodules ("primary cutaneous meningioma") are rare congenital lesions characterized by the presence of heterotopic mature cerebral tissues. Nasal glial heterotopia occurs predominantly in the nasal area and typically does not contain meningothelial elements, whereas heterotopic meningeal nodules occur predominantly on the scalp and do not contain glial elements. In this article, we report an unusual case of cutaneous heterotopia on the nose of an infant composed of both glial and meningothelial elements. The glial component was characterized by irregular islands of predominantly astrocytic cells, on a fibrillary background. The meningothelial component was characterized by bland ovoid cells with focal intranuclear inclusions forming whorled arrangements, with associated psammomatous calcification. To our knowledge, this is the first time such a lesion has been documented. It has also provided us with an opportunity to review the literature regarding heterotopic deposits of both glial and meningothelial tissues.

Petrosal ganglion: a more complex role than originally imagined.

PubMed

Retamal, Mauricio A; Reyes, Edison P; Alcayaga, Julio

2014-01-01

The petrosal ganglion (PG) is a peripheral sensory ganglion, composed of pseudomonopolar sensory neurons that innervate the posterior third of the tongue and the carotid sinus and body. According to their electrical properties PG neurons can be ascribed to one of two categories: (i) neurons with action potentials presenting an inflection (hump) on its repolarizing phase and (ii) neurons with fast and brisk action potentials. Although there is some correlation between the electrophysiological properties and the sensory modality of the neurons in some species, no general pattern can be easily recognized. On the other hand, petrosal neurons projecting to the carotid body are activated by several transmitters, with acetylcholine and ATP being the most conspicuous in most species. Petrosal neurons are completely surrounded by a multi-cellular sheet of glial (satellite) cells that prevents the formation of chemical or electrical synapses between neurons. Thus, PG neurons are regarded as mere wires that communicate the periphery (i.e., carotid body) and the central nervous system. However, it has been shown that in other sensory ganglia satellite glial cells and their neighboring neurons can interact, partly by the release of chemical neuro-glio transmitters. This intercellular communication can potentially modulate the excitatory status of sensory neurons and thus the afferent discharge. In this mini review, we will briefly summarize the general properties of PG neurons and the current knowledge about the glial-neuron communication in sensory neurons and how this phenomenon could be important in the chemical sensory processing generated in the carotid body.

Vesicular stomatitis virus infects resident cells of the central nervous system and induces replication-dependent inflammatory responses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chauhan, Vinita S.; Furr, Samantha R.; Sterka, David G.

2010-05-10

Vesicular stomatitis virus (VSV) infection of mice via intranasal administration results in a severe encephalitis with rapid activation and proliferation of microglia and astrocytes. We have recently shown that these glial cells express RIG-I and MDA5, cytosolic pattern recognition receptors for viral RNA. However, it is unclear whether VSV can replicate in glial cells or if such replication is required for their inflammatory responses. Here we demonstrate that primary microglia and astrocytes are permissive for VSV infection and limited productive replication. Importantly, we show that viral replication is required for robust inflammatory mediator production by these cells. Finally, we havemore » confirmed that in vivo VSV administration can result in viral infection of glial cells in situ. These results suggest that viral replication within resident glial cells might play an important role in CNS inflammation following infection with VSV and possibly other neurotropic nonsegmented negative-strand RNA viruses.« less

Neocortical glial cell numbers in human brains.

PubMed

Pelvig, D P; Pakkenberg, H; Stark, A K; Pakkenberg, B

2008-11-01

Stereological cell counting was applied to post-mortem neocortices of human brains from 31 normal individuals, age 18-93 years, 18 females (average age 65 years, range 18-93) and 13 males (average age 57 years, range 19-87). The cells were differentiated in astrocytes, oligodendrocytes, microglia and neurons and counting were done in each of the four lobes. The study showed that the different subpopulations of glial cells behave differently as a function of age; the number of oligodendrocytes showed a significant 27% decrease over adult life and a strong correlation to the total number of neurons while the total astrocyte number is constant through life; finally males have a 28% higher number of neocortical glial cells and a 19% higher neocortical neuron number than females. The overall total number of neocortical neurons and glial cells was 49.3 billion in females and 65.2 billion in males, a difference of 24% with a high biological variance. These numbers can serve as reference values in quantitative studies of the human neocortex.

Intraoperative electroacupuncture relieves remifentanil-induced postoperative hyperalgesia via inhibiting spinal glial activation in rats.

PubMed

Shi, Changxi; Liu, Yue; Zhang, Wei; Lei, Yishan; Lu, Cui'e; Sun, Rao; Sun, Yu'e; Jiang, Ming; Gu, Xiaoping; Ma, Zhengliang

2017-01-01

Background Accumulating studies have suggested that remifentanil, the widely-used opioid analgesic in clinical anesthesia, can activate the pronociceptive systems and enhance postoperative pain. Glial cells are thought to be implicated in remifentanil-induced hyperalgesia. Electroacupuncture is a complementary therapy to relieve various pain conditions with few side effects, and glial cells may be involved in its antinociceptive effect. In this study, we investigated whether intraoperative electroacupuncture could relieve remifentanil-induced postoperative hyperalgesia by inhibiting the activation of spinal glial cells, the production of spinal proinflammatory cytokines, and the activation of spinal mitogen-activated protein kinases. Methods A rat model of remifentanil-induced postoperative hyperalgesia was used in this study. Electroacupuncture during surgery was conducted at bilateral Zusanli (ST36) acupoints. Behavior tests, including mechanical allodynia and thermal hyperalgesia, were performed at different time points. Astrocytic marker glial fibrillary acidic protein, microglial marker Iba1, proinflammatory cytokines, and phosphorylated mitogen-activated protein kinases in the spinal cord were detected by Western blot and/or immunofluorescence. Results Mechanical allodynia and thermal hyperalgesia were induced by both surgical incision and remifentanil infusion, and remifentanil infusion significantly exaggerated and prolonged incision-induced pronociceptive effects. Glial fibrillary acidic protein, Iba1, proinflammatory cytokines (interleukin-1β and tumor necrosis factor-α), and phosphorylated mitogen-activated protein kinases (p-p38, p-JNK, and p-ERK1/2) were upregulated after surgical incision, remifentanil infusion, and especially after their combination. Intraoperative electroacupuncture significantly attenuated incision- and/or remifentanil-induced pronociceptive effects, spinal glial activation, proinflammatory cytokine upregulation, and phosphorylated mitogen-activated protein kinase upregulation. Conclusions Our study suggests that remifentanil-induced postoperative hyperalgesia can be relieved by intraoperative electroacupuncture via inhibiting the activation of spinal glial cells, the upregulation of spinal proinflammatory cytokines, and the activation of spinal mitogen-activated protein kinases.

Peripheral Glial Cells in the Development of Diabetic Neuropathy.

PubMed

Gonçalves, Nádia Pereira; Vægter, Christian Bjerggaard; Pallesen, Lone Tjener

2018-01-01

The global prevalence of diabetes is rapidly increasing, affecting more than half a billion individuals within the next few years. As diabetes negatively affects several physiological systems, this dramatic increase represents not only impaired quality of life on the individual level but also a huge socioeconomic challenge. One of the physiological consequences affecting up to half of diabetic patients is the progressive deterioration of the peripheral nervous system, resulting in spontaneous pain and eventually loss of sensory function, motor weakness, and organ dysfunctions. Despite intense research on the consequences of hyperglycemia on nerve functions, the biological mechanisms underlying diabetic neuropathy are still largely unknown, and treatment options lacking. Research has mainly focused directly on the neuronal component, presumably from the perspective that this is the functional signal-transmitting unit of the nerve. However, it is noteworthy that each single peripheral sensory neuron is intimately associated with numerous glial cells; the neuronal soma is completely enclosed by satellite glial cells and the length of the longest axons covered by at least 1,000 Schwann cells. The glial cells are vital for the neuron, but very little is still known about these cells in general and especially how they respond to diabetes in terms of altered neuronal support. We will discuss current knowledge of peripheral glial cells and argue that increased research in these cells is imperative for a better understanding of the mechanisms underlying diabetic neuropathy.

Peripheral Glial Cells in the Development of Diabetic Neuropathy

PubMed Central

Gonçalves, Nádia Pereira; Vægter, Christian Bjerggaard; Pallesen, Lone Tjener

2018-01-01

The global prevalence of diabetes is rapidly increasing, affecting more than half a billion individuals within the next few years. As diabetes negatively affects several physiological systems, this dramatic increase represents not only impaired quality of life on the individual level but also a huge socioeconomic challenge. One of the physiological consequences affecting up to half of diabetic patients is the progressive deterioration of the peripheral nervous system, resulting in spontaneous pain and eventually loss of sensory function, motor weakness, and organ dysfunctions. Despite intense research on the consequences of hyperglycemia on nerve functions, the biological mechanisms underlying diabetic neuropathy are still largely unknown, and treatment options lacking. Research has mainly focused directly on the neuronal component, presumably from the perspective that this is the functional signal-transmitting unit of the nerve. However, it is noteworthy that each single peripheral sensory neuron is intimately associated with numerous glial cells; the neuronal soma is completely enclosed by satellite glial cells and the length of the longest axons covered by at least 1,000 Schwann cells. The glial cells are vital for the neuron, but very little is still known about these cells in general and especially how they respond to diabetes in terms of altered neuronal support. We will discuss current knowledge of peripheral glial cells and argue that increased research in these cells is imperative for a better understanding of the mechanisms underlying diabetic neuropathy. PMID:29770116

Metabolic enzymes in glial cells of the honeybee brain and their associations with aging, starvation and food response.

PubMed

Shah, Ashish K; Kreibich, Claus D; Amdam, Gro V; Münch, Daniel

2018-01-01

The honey bee has been extensively studied as a model for neuronal circuit and memory function and more recently has emerged as an unconventional model in biogerontology. Yet, the detailed knowledge of neuronal processing in the honey bee brain contrasts with the very sparse information available on glial cells. In other systems glial cells are involved in nutritional homeostasis, detoxification, and aging. These glial functions have been linked to metabolic enzymes, such as glutamine synthetase and glycogen phosphorylase. As a step in identifying functional roles and potential differences among honey bee glial types, we examined the spatial distribution of these enzymes and asked if enzyme abundance is associated with aging and other processes essential for survival. Using immunohistochemistry and confocal laser microscopy we demonstrate that glutamine synthetase and glycogen phosphorylase are abundant in glia but appear to co-localize with different glial sub-types. The overall spatial distribution of both enzymes was not homogenous and differed markedly between different neuropiles and also within each neuropil. Using semi-quantitative Western blotting we found that rapid aging, typically observed in shortest-lived worker bees (foragers), was associated with declining enzyme levels. Further, we found enzyme abundance changes after severe starvation stress, and that glutamine synthetase is associated with food response. Together, our data indicate that aging and nutritional physiology in bees are linked to glial specific metabolic enzymes. Enzyme specific localization patterns suggest a functional differentiation among identified glial types.

Injury-induced ctgfa directs glial bridging and spinal cord regeneration in zebrafish

PubMed Central

Mokalled, Mayssa H.; Patra, Chinmoy; Dickson, Amy L.; Endo, Toyokazu; Stainier, Didier Y. R.; Poss, Kenneth D.

2016-01-01

Unlike mammals, zebrafish efficiently regenerate functional nervous system tissue after major spinal cord injury. Whereas glial scarring presents a roadblock for mammalian spinal cord repair, glial cells in zebrafish form a bridge across severed spinal cord tissue and facilitate regeneration, a relatively unexplored process. Here, we performed a genome-wide profiling screen for secreted factors that are upregulated during zebrafish spinal cord regeneration. We find that connective tissue growth factor a (ctgfa) is induced in and around glial cells that participate in initial bridging events. Mutations in ctgfa disrupt spinal cord repair, while transgenic ctgfa overexpression and local human CTGF recombinant protein delivery accelerate bridging and functional regeneration. Our study reveals that CTGF is necessary and sufficient to stimulate glial bridging and natural spinal cord regeneration. PMID:27811277

Changes in flip/flop splicing of astroglial AMPA receptors in human temporal lobe epilepsy.

PubMed

Seifert, Gerald; Schröder, Wolfgang; Hinterkeuser, Stefan; Schumacher, Thekla; Schramm, Johannes; Steinhäuser, Christian

2002-01-01

Recent data suggested a role for glial cells in epilepsy. This study sought to identify and functionally characterize AMPA receptors expressed by astrocytes in human hippocampal tissue resected from patients with intractable temporal lobe epilepsy. Patch-clamp and fast application methods were combined to investigate astrocytes in situ and after fresh isolation from the stratum radiatum of the hippocampal CA1 subfield. Relying on presurgical and histopathologic analysis, we divided human specimens into two groups, Ammon's horn sclerosis (AHS) and lesion-associated epilepsy. Fast application of glutamate and kainate evoked receptor currents in all cells studied. Reversal-potential analysis revealed an intermediate Ca2+ permeability of the receptor channels that did not vary between the two groups of patients. However, preapplication of the AMPA receptor-specific modulator, cyclothiazide, disclosed differences in flip-flop splicing. This treatment considerably enhanced the receptor conductance, with potentiation being significantly stronger in cells from AHS specimens compared with lesion-associated cells, suggesting upregulation of AMPA receptor flip splice variants in astrocytes of the sclerotic tissue. Compelling evidence has been accumulated showing direct and rapid signaling between neurons and glial cells. Our data suggest that in AHS patients, neuronally released glutamate will lead to an enhanced and prolonged depolarization of astrocytes, which might be involved in seizure generation and spread in this particular condition of human temporal lobe epilepsy.

Age-Related Changes in the Expression of the Circadian Clock Protein PERIOD in Drosophila Glial Cells

PubMed Central

Long, Dani M.; Giebultowicz, Jadwiga M.

2018-01-01

Circadian clocks consist of molecular negative feedback loops that coordinate physiological, neurological, and behavioral variables into “circa” 24-h rhythms. Rhythms in behavioral and other circadian outputs tend to weaken during aging, as evident in progressive disruptions of sleep-wake cycles in aging organisms. However, less is known about the molecular changes in the expression of clock genes and proteins that may lead to the weakening of circadian outputs. Western blot studies have demonstrated that the expression of the core clock protein PERIOD (PER) declines in the heads of aged Drosophila melanogaster flies. This age-related decline in PER does not occur in the central pacemaker neurons but has been demonstrated so far in retinal photoreceptors. Besides photoreceptors, clock proteins are also expressed in fly glia, which play important roles in neuronal homeostasis and are further categorized into subtypes based on morphology and function. While previous studies of mammalian glial cells have demonstrated the presence of functional clocks in astrocytes and microglia, it is not known which glial cell types in Drosophila express clock proteins and how their expression may change in aged individuals. Here, we conducted immunocytochemistry experiments to identify which glial subtypes express PER protein suggestive of functional circadian clocks. Glial cell subtypes that showed night-time accumulation and day-time absence in PER consistent with oscillations reported in the pacemaker neurons were selected to compare the level of PER protein between young and old flies. Our data demonstrate that some glial subtypes show rhythmic PER expression and the relative PER levels become dampened with advanced age. Identification of glial cell types that display age-related dampening of PER levels may help to understand the cellular changes that contribute to the loss of homeostasis in the aging brain. PMID:29375400

WDR62 Regulates Early Neural and Glial Progenitor Specification of Human Pluripotent Stem Cells

PubMed Central

Alshawaf, Abdullah J.; Antonic, Ana; Skafidas, Efstratios

2017-01-01

Mutations in WD40-repeat protein 62 (WDR62) are commonly associated with primary microcephaly and other developmental cortical malformations. We used human pluripotent stem cells (hPSC) to examine WDR62 function during human neural differentiation and model early stages of human corticogenesis. Neurospheres lacking WDR62 expression showed decreased expression of intermediate progenitor marker, TBR2, and also glial marker, S100β. In contrast, inhibition of c-Jun N-terminal kinase (JNK) signalling during hPSC neural differentiation induced upregulation of WDR62 with a corresponding increase in neural and glial progenitor markers, PAX6 and EAAT1, respectively. These findings may signify a role of WDR62 in specifying intermediate neural and glial progenitors during human pluripotent stem cell differentiation. PMID:28690640

Electrogenic glutamate uptake is a major current carrier in the membrane of axolotl retinal glial cells

NASA Astrophysics Data System (ADS)

Brew, Helen; Attwell, David

1987-06-01

Glutamate is taken up avidly by glial cells in the central nervous system1. Glutamate uptake may terminate the transmitter action of glutamate released from neurons1, and keep extracellular glutamate at concentrations below those which are neurotoxic. We report here that glutamate evokes a large inward current in retinal glial cells which have their membrane potential and intracellular ion concentrations controlled by the whole-cell patch-clamp technique2. This current seems to be due to an electrogenic glutamate uptake carrier, which transports at least two sodium ions with every glutamate anion carried into the cell. Glutamate uptake is strongly voltage-dependent, decreasing at depolarized potentials: when fully activated, it contributes almost half of the conductance in the part of the glial cell membrane facing the retinal neurons. The spatial localization, glutamate affinity and magnitude of the uptake are appropriate for terminating the synaptic action of glutamate released from photoreceptors and bipolar cells. These data challenge present explanations of how the b-wave of the electroretinogram is generated, and suggest a mechanism for non-vesicular voltage-dependent release of glutamate from neurons.

Immunoreactive opsin and glial fibrillary acidic protein in persistent hyperplastic primary vitreous.

PubMed

Hara, S; Mito, T; Takahashi, M; Ohmura, M; Mizuno, K; Masuda, T

1988-08-01

An 8-month-old boy had an anterior type of persistent hyperplastic primary vitreous in the right eye. Results of needle biopsy, performed because of elevated intraocular pressure, disclosed clusters of blastic cells. The eye was enucleated on the suspicion of retinoblastoma. Histological examination showed retrolental fibrovascular tissue and retinal dysplasia. Immunoreactive opsin was detected in the innermost structures and in photoreceptor-like cells of rosettes. We conclude that photoreceptor cells differentiated to express opsin, even when neighbouring cells were abnormally arranged. An immunocytochemical study of glial fibrillary acidic protein demonstrated glial proliferation in the inner layer of the retina but not in the preretinal space.

Genetics Home Reference: megalencephalic leukoencephalopathy with subcortical cysts

MedlinePlus

... is unable to correctly transport GlialCAM and MLC1 proteins to cell junctions. It is unknown how a lack of functional MLC1 or GlialCAM protein at cell junctions in the brain impairs brain development and ...

Fetal Alcohol Spectrum Disorders: An Overview from the Glia Perspective.

PubMed

Wilhelm, Clare J; Guizzetti, Marina

2015-01-01

Alcohol consumption during pregnancy can produce a variety of central nervous system (CNS) abnormalities in the offspring resulting in a broad spectrum of cognitive and behavioral impairments that constitute the most severe and long-lasting effects observed in fetal alcohol spectrum disorders (FASD). Alcohol-induced abnormalities in glial cells have been suspected of contributing to the adverse effects of alcohol on the developing brain for several years, although much research still needs to be done to causally link the effects of alcohol on specific brain structures and behavior to alterations in glial cell development and function. Damage to radial glia due to prenatal alcohol exposure may underlie observations of abnormal neuronal and glial migration in humans with Fetal Alcohol Syndrome (FAS), as well as primate and rodent models of FAS. A reduction in cell number and altered development has been reported for several glial cell types in animal models of FAS. In utero alcohol exposure can cause microencephaly when alcohol exposure occurs during the brain growth spurt a period characterized by rapid astrocyte proliferation and maturation; since astrocytes are the most abundant cells in the brain, microenchephaly may be caused by reduced astrocyte proliferation or survival, as observed in in vitro and in vivo studies. Delayed oligodendrocyte development and increased oligodendrocyte precursor apoptosis has also been reported in experimental models of FASD, which may be linked to altered myelination/white matter integrity found in FASD children. Children with FAS exhibit hypoplasia of the corpus callosum and anterior commissure, two areas requiring guidance from glial cells and proper maturation of oligodendrocytes. Finally, developmental alcohol exposure disrupts microglial function and induces microglial apoptosis; given the role of microglia in synaptic pruning during brain development, the effects of alcohol on microglia may be involved in the abnormal brain plasticity reported in FASD. The consequences of prenatal alcohol exposure on glial cells, including radial glia and other transient glial structures present in the developing brain, astrocytes, oligodendrocytes and their precursors, and microglia contributes to abnormal neuronal development, reduced neuron survival and disrupted brain architecture and connectivity. This review highlights the CNS structural abnormalities caused by in utero alcohol exposure and outlines which abnormalities are likely mediated by alcohol effects on glial cell development and function.

Modulation of opioid actions by nitric oxide signaling.

PubMed

Toda, Noboru; Kishioka, Shiroh; Hatano, Yoshio; Toda, Hiroshi

2009-01-01

Nitric oxide (NO) plays pivotal roles in controlling physiological functions, participates in pathophysiological intervention, and is involved in mechanisms underlying beneficial or untoward actions of therapeutic agents. Endogenous nitric oxide is formed by three isoforms of nitric oxide synthase: endothelial, neurogenic and inducible. The former two are constitutively present mainly in the endothelium and nervous system, respectively, and the latter one is induced by lipopolysaccharides or cytokines mainly in mitochondria and glial cells. Constitutively formed nitric oxide modulates the actions of morphine and related analgesics by either enhancing or reducing antinociception. Tolerance to and dependence on morphine or its withdrawal syndrome are likely prevented by nitric oxide synthase inhibition. Information concerning modulation of morphine actions by nitric oxide is undoubtedly useful in establishing new strategies for efficient antinociceptive treatment and for minimizing noxious and unintended reactions.

Kif11 dependent cell cycle progression in radial glial cells is required for proper neurogenesis in the zebrafish neural tube.

PubMed

Johnson, Kimberly; Moriarty, Chelsea; Tania, Nessy; Ortman, Alissa; DiPietrantonio, Kristina; Edens, Brittany; Eisenman, Jean; Ok, Deborah; Krikorian, Sarah; Barragan, Jessica; Golé, Christophe; Barresi, Michael J F

2014-03-01

Radial glia serve as the resident neural stem cells in the embryonic vertebrate nervous system, and their proliferation must be tightly regulated to generate the correct number of neuronal and glial cell progeny in the neural tube. During a forward genetic screen, we recently identified a zebrafish mutant in the kif11 loci that displayed a significant increase in radial glial cell bodies at the ventricular zone of the spinal cord. Kif11, also known as Eg5, is a kinesin-related, plus-end directed motor protein responsible for stabilizing and separating the bipolar mitotic spindle. We show here that Gfap+ radial glial cells express kif11 in the ventricular zone and floor plate. Loss of Kif11 by mutation or pharmacological inhibition with S-trityl-L-cysteine (STLC) results in monoastral spindle formation in radial glial cells, which is characteristic of mitotic arrest. We show that M-phase radial glia accumulate over time at the ventricular zone in kif11 mutants and STLC treated embryos. Mathematical modeling of the radial glial accumulation in kif11 mutants not only confirmed an ~226× delay in mitotic exit (likely a mitotic arrest), but also predicted two modes of increased cell death. These modeling predictions were supported by an increase in the apoptosis marker, anti-activated Caspase-3, which was also found to be inversely proportional to a decrease in cell proliferation. In addition, treatment with STLC at different stages of neural development uncovered two critical periods that most significantly require Kif11 function for stem cell progression through mitosis. We also show that loss of Kif11 function causes specific reductions in oligodendroglia and secondary interneurons and motorneurons, suggesting these later born populations require proper radial glia division. Despite these alterations to cell cycle dynamics, survival, and neurogenesis, we document unchanged cell densities within the neural tube in kif11 mutants, suggesting that a mechanism of compensatory regulation may exist to maintain overall proportions in the neural tube. We propose a model in which Kif11 normally functions during mitotic spindle formation to facilitate the progression of radial glia through mitosis, which leads to the maturation of progeny into specific secondary neuronal and glial lineages in the developing neural tube. Copyright © 2014. Published by Elsevier Inc.

Kif11 dependent cell cycle progression in radial glial cells is required for proper neurogenesis in the zebrafish neural tube

PubMed Central

Johnson, Kimberly; Moriarty, Chelsea; Tania, Nessy; Ortman, Alissa; DiPietrantonio, Kristina; Edens, Brittany; Eisenman, Jean; Ok, Deborah; Krikorian, Sarah; Barragan, Jessica; Gole, Christophe; Barresi, Michael J.F.

2014-01-01

Radial glia serve as the resident neural stem cells in the embryonic vertebrate nervous system, and their proliferation must be tightly regulated to generate the correct number of neuronal and glial cell progeny in the neural tube. During a forward genetic screen, we recently identified a zebrafish mutant in the kif11 loci that displayed a significant increase in radial glial cell bodies at the ventricular zone of the spinal cord. Kif11, also known as Eg5, is a kinesin-related, plus-end directed motor protein responsible for stabilizing and separating the bipolar mitotic spindle. We show here that Gfap+ radial glial cells express kif11 in the ventricular zone and floor plate. Loss of Kif11 by mutation or pharmacological inhibition with S-trityl-L-cysteine (STLC) results in monoastral spindle formation in radial glial cells, which is characteristic of mitotic arrest. We show that M-phase radial glia accumulate over time at the ventricular zone in kif11 mutants and STLC treated embryos. Mathematical modeling of the radial glial accumulation in kif11 mutants not only confirmed an ~226x delay in mitotic exit (likely a mitotic arrest), but also predicted two modes of increased cell death. These modeling predictions were supported by an increase in the apoptosis marker, anti-activated Caspase-3, which was also found to be inversely proportional to a decrease in cell proliferation. In addition, treatment with STLC at different stages of neural development uncovered two critical periods that most significantly require Kif11 function for stem cell progression through mitosis. We also show that loss of Kif11 function causes specific reductions in oligodendroglia and secondary interneurons and motorneurons, suggesting these later born populations require proper radial glia division. Despite these alterations to cell cycle dynamics, survival, and neurogenesis, we document unchanged cell densities within the neural tube in kif11 mutants, suggesting that a mechanism of compensatory regulation may exist to maintain overall proportions in the neural tube. We propose a model in which Kif11 normally functions during mitotic spindle formation to facilitate the progression of radial glia through mitosis, which leads to the maturation of progeny into specific secondary neuronal and glial lineages in the developing neural tube. PMID:24370453

Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen.

PubMed

Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

2013-02-01

Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca(2+) waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of adult (8- to 15-week-old) and aging (48- to 80-week-old) ketamine-anesthetized mice after bolus loading with OGB-1/AM and SR101. We report that the occurrence of spontaneous waves is 20 times more frequent in the cerebellar cortex of aging as compared with adult mice, which correlated with a reduction in resting brain oxygen tension. In adult mice, spontaneous glial wave activity increased on reducing resting brain oxygen tension, and ATP-evoked glial waves reduced the tissue O(2) tension. Finally, although spontaneous Purkinje cell (PC) activity was not associated with increased glia wave activity, spontaneous glial waves did affect intracellular Ca(2+) activity in PCs. The increased wave activity during aging, as well as low resting brain oxygen tension, suggests a relationship between glial waves, brain energy homeostasis, and pathology.

The Reactivity, Distribution and Abundance of Non-Astrocytic Inner Retinal Glial (NIRG) Cells Are Regulated by Microglia, Acute Damage, and IGF1

PubMed Central

Zelinka, Christopher P.; Scott, Melissa A.; Volkov, Leo; Fischer, Andy J.

2012-01-01

Recent studies have described a novel type of glial cell that is scattered across the inner layers of the avian retina and possibly the retinas of primates. These cells have been termed Non-astrocytic Inner Retinal Glial (NIRG) cells. These cells are stimulated by insulin-like growth factor 1 (IGF1) to proliferate, migrate distally into the retina, and become reactive. These changes in glial activity correlate with increased susceptibility of retinal neurons and Müller glia to excitotoxic damage. The purpose of this study was to further study the NIRG cells in retinas treated with IGF1 or acute damage. In response to IGF1, the reactivity, proliferation and migration of NIRG cells persists through 3 days after treatment. At 7 days after treatment, the numbers and distribution of NIRG cells returns to normal, suggesting that homeostatic mechanisms are in place within the retina to maintain the numbers and distribution of these glial cells. By comparison, IGF1-induced microglial reactivity persists for at least 7 days after treatment. In damaged retinas, we find a transient accumulation of NIRG cells, which parallels the accumulation of reactive microglia, suggesting that the reactivity of NIRG cells and microglia are linked. When the microglia are selectively ablated by the combination of interleukin 6 and clodronate-liposomes, the NIRG cells down-regulate transitin and perish within the following week, suggesting that the survival and phenotype of NIRG cells are somehow linked to the microglia. We conclude that the abundance, reactivity and retinal distribution of NIRG cells can be dynamic, are regulated by homoestatic mechanisms and are tethered to the microglia. PMID:22973454

The glial investment of the adult and developing antennal lobe of Drosophila

PubMed Central

Oland, Lynne A.; Biebelhausen, John P.; Tolbert, Leslie P.

2009-01-01

In recent years, the Drosophila olfactory system, with its unparalleled opportunities for genetic dissection of development and functional organization, has been used to study the development of central olfactory neurons and the molecular basis of olfactory coding. The results of these studies have been interpreted in the absence of a detailed understanding of the steps in maturation of glial cells in the antennal lobe. Here, we present a high-resolution study of the glia associated with olfactory glomeruli in adult and developing antennal lobes. The study provides a basis for comparison of findings in Drosophila with those in the moth Manduca sexta that indicate a critical role for glia in antennal lobe development. Using flies expressing GFP under a Nervana2 driver to visualize glia for confocal microscopy, and probing at higher resolution with the electron microscope, we find that glial development in Drosophila differs markedly from that in moths: glial cell bodies remain in a rind around the glomerular neuropil; glial processes ensheathe axon bundles in the nerve layer but likely contribute little to axonal sorting; their processes insinuate between glomeruli only very late and then form only a sparse, open network around each glomerulus; and glial processes invade the synaptic neuropil. Taking our results in the context of previous studies, we conclude that glial cells in the developing Drosophila antennal lobe are unlikely to play a strong role in either axonal sorting or glomerulus stabilization and that in the adult, glial processes do not electrically isolate glomeruli from their neighbors. PMID:18537134

Glia: the not so innocent bystanders.

PubMed

Chao, C C; Hu, S; Peterson, P K

1996-08-01

Activated glial cells (microglia and astrocytes) are a hallmark of a variety of neurodegenerative diseases. Recent in vitro studies have suggested that mediators derived from reactive glial cells (eg, cytokines, reactive oxygen intermediates, nitric oxide, glutamate or quinolinic acids, and neurotoxins) contribute to neuronal injury. Several of these mediators have been implicated in the neuropathogenesis of HIV-1. Although the precise role of glial cell-mediated neurotoxicity in viral infections of the central nervous system has not been established, it is hoped that research in this field will yield new therapies for these infections as well as for immune-mediated neurodegenerative diseases.

The role of glia in late-life depression.

PubMed

Paradise, Matt Bennett; Naismith, Sharon Linda; Norrie, Louisa Margaret; Graeber, Manuel Benedikt; Hickie, Ian Bernard

2012-12-01

Late-life depression (LLD) has a complex and multifactoral etiology. There is growing interest in elucidating how glia, acting alone or as part of a glial-neuronal network, may contribute to the pathophysiology of depression. In this paper, we explore results from neuroimaging studies showing gray-matter volume loss in key frontal and subcortical structures implicated in LLD, and present the few histological studies that have examined neuronal and glial densities in these regions. Compared to results in younger people with depression, there appear to be age-dependent differences in neuronal pathology but the changes in glial pathology may be more subtle, perhaps reflecting a longer-term compensatory gliosis to earlier damage. We then consider the mechanisms by which both astrocytes and microglia may mediate and modulate neuronal dysfunction and possible degeneration in depression. These include a critical role in the response to peripheral inflammation and central microglial activation, as well as a key role in glutamate metabolism. Advances in our understanding of glia are highlighted, including the role of microglia as "electricians" of the brain and astrocytes as key communicating cells, an integral part of the tripartite synapse. Finally, implications for clinicians are discussed, including the consideration of glia as biomarkers for LLD and incorporation of glia into future therapeutic strategies.

Adaptive Calcified Matrix Response of Dental Pulp to Bacterial Invasion Is Associated with Establishment of a Network of Glial Fibrillary Acidic Protein+/Glutamine Synthetase+ Cells

PubMed Central

Farahani, Ramin M.; Nguyen, Ky-Anh; Simonian, Mary; Hunter, Neil

2010-01-01

We report evidence for anatomical and functional changes of dental pulp in response to bacterial invasion through dentin that parallel responses to noxious stimuli reported in neural crest-derived sensory tissues. Sections of resin-embedded carious adult molar teeth were prepared for immunohistochemistry, in situ hybridization, ultrastructural analysis, and microdissection to extract mRNA for quantitative analyses. In odontoblasts adjacent to the leading edge of bacterial invasion in carious teeth, expression levels of the gene encoding dentin sialo-protein were 16-fold greater than in odontoblasts of healthy teeth, reducing progressively with distance from this site of the carious lesion. In contrast, gene expression for dentin matrix protein-1 by odontoblasts was completely suppressed in carious teeth relative to healthy teeth. These changes in gene expression were related to a gradient of deposited reactionary dentin that displayed a highly modified structure. In carious teeth, interodontoblastic dentin sialo-protein− cells expressing glutamine synthetase (GS) showed up-regulation of glial fibrillary acidic protein (GFAP). These cells extended processes that associated with odontoblasts. Furthermore, connexin 43 established a linkage between adjacent GFAP+/GS+ cells in carious teeth only. These findings indicate an adaptive pulpal response to encroaching caries that includes the deposition of modified, calcified, dentin matrix associated with networks of GFAP+/GS+ interodontoblastic cells. A regulatory role for the networks of GFAP+/GS+ cells is proposed, mediated by the secretion of glutamate to modulate odontoblastic response. PMID:20802180

Monocrotophos Induces the Expression of Xenobiotic Metabolizing Cytochrome P450s (CYP2C8 and CYP3A4) and Neurotoxicity in Human Brain Cells.

PubMed

Tripathi, Vinay Kumar; Kumar, Vivek; Pandey, Ankita; Vatsa, Pankhi; Dhasmana, Anupam; Singh, Rajat Pratap; Appikonda, Sri Hari Chandan; Hwang, Inho; Lohani, Mohtashim

2017-07-01

Expression of various cytochrome P450s (CYPs) in mammalian brain cells is well documented. However, such studies are hampered in neural/glial cells of human origin due to nonavailability of human brain cells. To address this issue, we investigated the expression and inducibility of CYP2C8 and CYP3A4 and their responsiveness against cyclophosphamide (CPA) and organophosphorus pesticide monocrotophos (MCP), a known developmental neurotoxicant in human neural (SH-SY5Y) and glial (U373-MG) cell lines. CPA induced significant expression of CYP2C8 and CYP3A4 in both types of cells in a time-dependent manner. Neural cell line exhibited relatively higher constitutive and inducible expression of CYPs than the glial cell line. MCP exposure alone could not induce the significant expression of CYPs, whereas the cells preexposed to CPA showed a significant response to MCP. Similar to the case of CPA induced expressions, neural cells were found to be more vulnerable than glial cells. Our data indicate differential expressions of CYPs in cultured human neural and glial cell lines. The findings were synchronized with protein ligand docking studies, which showed a significant modulatory capacity of MCP by strong interaction with CYP regulators-CAR and PXR. Similarly, the known CYP inducer CPA has also shown significant high docking scores with the two studied CYP regulators. We also observed a significant induction in reactive oxygen species (ROS), lipid peroxides (LPO), micronucleus (MN), chromosomal aberration (CA), and reduction in reduced glutathione (GSH) and catalase following the exposure of MCP. Moreover, the expressions of apoptotic markers such as caspase-3, caspase-9, Bax, and p53 were significantly upregulated, whereas the levels of antiapoptotic marker, Bcl2, was downregulated after the exposure of MCP in both cell lines. These findings confirm the involvement of ROS-mediated oxidative stress, which subsequently triggers apoptosis pathways in both human neural (SH-SY5Y) and glial (U373-MG) cell lines following the exposure of MCP.

Comparison of Individual and Combined Effects of Four Endocrine Disruptors on Estrogen Receptor Beta Transcription in Cerebellar Cell Culture: The Modulatory Role of Estradiol and Triiodo-Thyronine

PubMed Central

Jocsak, Gergely; Kiss, David Sandor; Toth, Istvan; Goszleth, Greta; Bartha, Tibor; Frenyo, Laszlo V.; Horvath, Tamas L.; Zsarnovszky, Attila

2016-01-01

Background: Humans and animals are continuously exposed to a number of environmental substances that act as endocrine disruptors (EDs). While a growing body of evidence is available to prove their adverse health effects, very little is known about the consequences of simultaneous exposure to a combination of such chemicals; Methods: Here, we used an in vitro model to demonstrate how exposure to bisphenol A, zearalenone, arsenic, and 4-methylbenzylidene camphor, alone or in combination, affect estrogen receptor β (ERβ) mRNA expression in primary cerebellar cell cultures. Additionally, we also show the modulatory role of intrinsic biological factors, such as estradiol (E2), triiodo-thyronine (T3), and glial cells, as potential effect modulators; Results: Results show a wide diversity in ED effects on ERβ mRNA expression, and that the magnitude of these ED effects highly depends on the presence or absence of E2, T3, and glial cells; Conclusion: The observed potency of the EDs to influence ERβ mRNA expression, and the modulatory role of E2, T3, and the glia suggests that environmental ED effects may be masked as long as the hormonal milieu is physiological, but may tend to turn additive or superadditive in case of hormone deficiency. PMID:27338438

PACAP signaling to DREAM: a cAMP-dependent pathway that regulates cortical astrogliogenesis.

PubMed

Vallejo, Mario

2009-04-01

Astrocytes constitute a very abundant cell type in the mammalian central nervous system and play critical roles in brain function. During development, astrocytes are generated from neural progenitor cells only after these cells have generated neurons. This so called gliogenic switch is tightly regulated by intrinsic factors that inhibit the generation of astrocytes during the neurogenic period. Once neural progenitors acquire gliogenic competence, they differentiate into astrocytes in response to specific extracellular signals. Some of these signals are delivered by neurotrophic cytokines via activation of the gp130-JAK-signal transducer and activator of transcription system, whereas others depend on the activity of pituitary adenylate cyclase-activating polypeptide (PACAP) on specific PAC1 receptors that stimulate the production of cAMP. This results in the activation of the small GTPases Rap1 and Ras, and in the cAMP-dependent entry of extracellular calcium into the cell. Calcium, in turn, stimulates the transcription factor downstream regulatory element antagonist modulator (DREAM), which is bound to specific sites of the promoter of the glial fibrillary acidic protein gene, stimulating its expression during astrocyte differentiation. Lack of DREAM in vivo results in alterations in the number of neurons and astrocytes generated during development. Thus, the PACAP-cAMP-Ca(2+)-DREAM signaling cascade constitutes an important pathway to activate glial-specific gene expression during astrocyte differentiation.

Synergistic Toxicity of Polyglutamine-Expanded TATA-Binding Protein in Glia and Neuronal Cells: Therapeutic Implications for Spinocerebellar Ataxia 17

PubMed Central

Yang, Yang; Cui, Yiting; Tang, Beisha

2017-01-01

Spinocerebellar ataxia 17 (SCA17) is caused by polyglutamine (polyQ) repeat expansion in the TATA-binding protein (TBP) and is among a family of neurodegenerative diseases in which polyQ expansion leads to preferential neuronal loss in the brain. Although previous studies have demonstrated that expression of polyQ-expanded proteins in glial cells can cause neuronal injury via noncell-autonomous mechanisms, these studies investigated animal models that overexpress transgenic mutant proteins. Since glial cells are particularly reactive to overexpressed mutant proteins, it is important to investigate the in vivo role of glial dysfunction in neurodegeneration when mutant polyQ proteins are endogenously expressed. In the current study, we generated two conditional TBP-105Q knock-in mouse models that specifically express mutant TBP at the endogenous level in neurons or in astrocytes. We found that mutant TBP expression in neuronal cells or astrocytes alone only caused mild neurodegeneration, whereas severe neuronal toxicity requires the expression of mutant TBP in both neuronal and glial cells. Coculture of neurons and astrocytes further validated that mutant TBP in astrocytes promoted neuronal injury. We identified activated inflammatory signaling pathways in mutant TBP-expressing astrocytes, and blocking nuclear factor κB (NF-κB) signaling in astrocytes ameliorated neurodegeneration. Our results indicate that the synergistic toxicity of mutant TBP in neuronal and glial cells plays a critical role in SCA17 pathogenesis and that targeting glial inflammation could be a potential therapeutic approach for SCA17 treatment. SIGNIFICANCE STATEMENT Mutant TBP with polyglutamine expansion preferentially affects neuronal viability in SCA17 patients. Whether glia, the cells that support and protect neurons, contribute to neurodegeneration in SCA17 remains mostly unexplored. In this study, we provide both in vivo and in vitro evidence arguing that endogenous expression of mutant TBP in neurons and glia synergistically impacts neuronal survival. Hyperactivated inflammatory signaling pathways, particularly the NF-κB pathway, underlie glia-mediated neurotoxicity. Moreover, blocking NF-κB activity with small chemical inhibitors alleviated such neurotoxicity. Our study establishes glial dysfunction as an important component of SCA17 pathogenesis and suggests targeting glial inflammation as a potential therapeutic approach for SCA17 treatment. PMID:28821675

Medicinal cannabis: rational guidelines for dosing.

PubMed

Carter, Gregory T; Weydt, Patrick; Kyashna-Tocha, Muraco; Abrams, Donald I

2004-05-01

The medicinal value of cannabis (marijuana) is well documented in the medical literature. Cannabinoids, the active ingredients in cannabis, have many distinct pharmacological properties. These include analgesic, anti-emetic, anti-oxidative, neuroprotective and anti-inflammatory activity, as well as modulation of glial cells and tumor growth regulation. Concurrent with all these advances in the understanding of the physiological and pharmacological mechanisms of cannabis, there is a strong need for developing rational guidelines for dosing. This paper will review the known chemistry and pharmacology of cannabis and, on that basis, discuss rational guidelines for dosing.

Cannabis: old medicine with new promise for neurological disorders.

PubMed

Carter, Gregory T; Weydt, Patrick

2002-03-01

Marijuana is a complex substance containing over 60 different forms of cannabinoids, the active ingredients. Cannabinoids are now known to have the capacity for neuromodulation, via direct, receptor-based mechanisms at numerous levels within the nervous system. These have therapeutic properties that may be applicable to the treatment of neurological disorders; including anti-oxidative, neuroprotective, analgesic and anti-inflammatory actions; immunomodulation, modulation of glial cells and tumor growth regulation. This article reviews the emerging research on the physiological mechanisms of endogenous and exogenous cannabinoids in the context of neurological disease.

Medical marijuana: emerging applications for the management of neurologic disorders.

PubMed

Carter, Gregory T; Ugalde, Vivian

2004-11-01

Marijuana contains over 60 different types of cannabinoids, which are its medicinally active ingredients. Cannabinoids have the capacity for neuromodulation--through direct, receptor-based mechanisms--at many levels within the nervous system, providing therapeutic properties that may be applicable to the treatment of neurologic disorders. These include antioxidation, neuroprotection, analgesia, anti-inflammation, immunomodulation, modulation of glial cells, and tumor growth regulation. This article reviews the current and emerging research on the physiologic mechanisms of endogenous and exogenous cannabinoids and their applications in the management of neurologic disease.

Administration of the glial cell modulator, minocycline, in the nucleus accumbens attenuated the maintenance and reinstatement of morphine-seeking behavior.

PubMed

Arezoomandan, Reza; Haghparast, Abbas

2016-03-01

Relapse to drug use is one of the most difficult clinical problems in treating addiction. Glial activation has been linked with the drug abuse, and the glia modulators such as minocycline can modulate the drug abuse effects. The aim of the present study was to determine whether minocycline could attenuate the maintenance and reinstatement of morphine. Conditioned place preference (CPP) was induced by subcutaneous injection of morphine (5 mg/kg) for 3 days. Following the acquisition of the CPP, the rats were given daily bilateral intra-NAc injections of either minocycline (1, 5, and 10 μg/0.5 μL) or saline (0.5 μL). The animals were tested for conditioning score 60 min after each injection. To induce the reinstatement, a priming dose of morphine (1 mg/kg) was injected 1 day after the final extinction day. The morphine-induced CPP lasted for 7 days after cessation of morphine treatment. Our data revealed that a priming dose of morphine could reinstate the extinguished morphine-induced CPP. Daily intra-accumbal injection of minocycline during the extinction period blocked the maintenance of morphine CPP and also attenuated the priming-induced reinstatement. Our findings indicated that minocycline could facilitate the extinction and attenuate the reinstatement of morphine. These results provided new evidence that minocycline might be considered as a promising therapeutic agent for the treatment of several symptoms associated with morphine abuse.

Deficient GABAergic gliotransmission may cause broader sensory tuning in schizophrenia.

PubMed

Hoshino, Osamu

2013-12-01

We examined how the depression of intracortical inhibition due to a reduction in ambient GABA concentration impairs perceptual information processing in schizophrenia. A neural network model with a gliotransmission-mediated ambient GABA regulatory mechanism was simulated. In the network, interneuron-to-glial-cell and principal-cell-to-glial-cell synaptic contacts were made. The former hyperpolarized glial cells and let their transporters import (remove) GABA from the extracellular space, thereby lowering ambient GABA concentration, reducing extrasynaptic GABAa receptor-mediated tonic inhibitory current, and thus exciting principal cells. In contrast, the latter depolarized the glial cells and let the transporters export GABA into the extracellular space, thereby elevating the ambient GABA concentration and thus inhibiting the principal cells. A reduction in ambient GABA concentration was assumed for a schizophrenia network. Multiple dynamic cell assemblies were organized as sensory feature columns. Each cell assembly responded to one specific feature stimulus. The tuning performance of the network to an applied feature stimulus was evaluated in relation to the level of ambient GABA. Transporter-deficient glial cells caused a deficit in GABAergic gliotransmission and reduced ambient GABA concentration, which markedly deteriorated the tuning performance of the network, broadening the sensory tuning. Interestingly, the GABAergic gliotransmission mechanism could regulate local ambient GABA levels: it augmented ambient GABA around stimulus-irrelevant principal cells, while reducing ambient GABA around stimulus-relevant principal cells, thereby ensuring their selective responsiveness to the applied stimulus. We suggest that a deficit in GABAergic gliotransmission may cause a reduction in ambient GABA concentration, leading to a broadening of sensory tuning in schizophrenia. The GABAergic gliotransmission mechanism proposed here may have an important role in the regulation of local ambient GABA levels, thereby improving the sensory tuning performance of the cortex.

Early effects of iodine deficiency on radial glial cells of the hippocampus of the rat fetus. A model of neurological cretinism.

PubMed Central

Martínez-Galán, J R; Pedraza, P; Santacana, M; Escobar del Ray, F; Morreale de Escobar, G; Ruiz-Marcos, A

1997-01-01

The most severe brain damage associated with thyroid dysfunction during development is observed in neurological cretins from areas with marked iodine deficiency. The damage is irreversible by birth and related to maternal hypothyroxinemia before mid gestation. However, direct evidence of this etiopathogenic mechanism is lacking. Rats were fed diets with a very low iodine content (LID), or LID supplemented with KI. Other rats were fed the breeding diet with a normal iodine content plus a goitrogen, methimazole (MMI). The concentrations of -thyroxine (T4) and 3,5,3'triiodo--thyronine (T3) were determined in the brain of 21-d-old fetuses. The proportion of radial glial cell fibers expressing nestin and glial fibrillary acidic protein was determined in the CA1 region of the hippocampus. T4 and T3 were decreased in the brain of the LID and MMI fetuses, as compared to their respective controls. The number of immature glial cell fibers, expressing nestin, was not affected, but the proportion of mature glial cell fibers, expressing glial fibrillary acidic protein, was significantly decreased by both LID and MMI treatment of the dams. These results show impaired maturation of cells involved in neuronal migration in the hippocampus, a region known to be affected in cretinism, at a stage of development equivalent to mid gestation in humans. The impairment is related to fetal cerebral thyroid hormone deficiency during a period of development when maternal thyroxinemia is believed to play an important role. PMID:9169500

Acute Neuroimmune Modulation Attenuates the Development of Anxiety-Like Freezing Behavior in an Animal Model of Traumatic Brain Injury

PubMed Central

Rodgers, Krista M.; Bercum, Florencia M.; McCallum, Danielle L.; Rudy, Jerry W.; Frey, Lauren C.; Johnson, Kirk W.; Watkins, Linda R.

2012-01-01

Abstract Chronic anxiety is a common and debilitating result of traumatic brain injury (TBI) in humans. While little is known about the neural mechanisms of this disorder, inflammation resulting from activation of the brain's immune response to insult has been implicated in both human post-traumatic anxiety and in recently developed animal models. In this study, we used a lateral fluid percussion injury (LFPI) model of TBI in the rat and examined freezing behavior as a measure of post-traumatic anxiety. We found that LFPI produced anxiety-like freezing behavior accompanied by increased reactive gliosis (reflecting neuroimmune inflammatory responses) in key brain structures associated with anxiety: the amygdala, insula, and hippocampus. Acute peri-injury administration of ibudilast (MN166), a glial cell activation inhibitor, suppressed both reactive gliosis and freezing behavior, and continued neuroprotective effects were apparent several months post-injury. These results support the conclusion that inflammation produced by neuroimmune responses to TBI play a role in post-traumatic anxiety, and that acute suppression of injury-induced glial cell activation may have promise for the prevention of post-traumatic anxiety in humans. PMID:22435644

Transcranial amelioration of inflammation and cell death after brain injury

NASA Astrophysics Data System (ADS)

Roth, Theodore L.; Nayak, Debasis; Atanasijevic, Tatjana; Koretsky, Alan P.; Latour, Lawrence L.; McGavern, Dorian B.

2014-01-01

Traumatic brain injury (TBI) is increasingly appreciated to be highly prevalent and deleterious to neurological function. At present, no effective treatment options are available, and little is known about the complex cellular response to TBI during its acute phase. To gain insights into TBI pathogenesis, we developed a novel murine closed-skull brain injury model that mirrors some pathological features associated with mild TBI in humans and used long-term intravital microscopy to study the dynamics of the injury response from its inception. Here we demonstrate that acute brain injury induces vascular damage, meningeal cell death, and the generation of reactive oxygen species (ROS) that ultimately breach the glial limitans and promote spread of the injury into the parenchyma. In response, the brain elicits a neuroprotective, purinergic-receptor-dependent inflammatory response characterized by meningeal neutrophil swarming and microglial reconstitution of the damaged glial limitans. We also show that the skull bone is permeable to small-molecular-weight compounds, and use this delivery route to modulate inflammation and therapeutically ameliorate brain injury through transcranial administration of the ROS scavenger, glutathione. Our results shed light on the acute cellular response to TBI and provide a means to locally deliver therapeutic compounds to the site of injury.

Protective effect of naringin on 3-nitropropionic acid-induced neurodegeneration through the modulation of matrix metalloproteinases and glial fibrillary acidic protein.

PubMed

Gopinath, Kulasekaran; Sudhandiran, Ganapasam

2016-01-01

Naringin (4',5,7-trihydroxy-flavonone-7-rhamnoglucoside), a flavonone present in grapefruit, has recently been reported to protect against neurodegeration, induced with 3-nitropropionic acid (3-NP), through its antioxidant, anti-inflammatory, and antiapoptotic properties. This study used a rat model of 3-NP-induced neurodegeneration to investigate the neuroprotective effects of naringin exerted by modulating the expression of matrix metalloproteinases and glial fibrillary acidic protein. Neurodegeneration was induced with 3-NP (10 mg/kg body mass, by intraperitoneal injection) once a day for 2 weeks, and induced rats were treated with naringin (80 mg/kg body mass, by oral gavage, once a day for 2 weeks). Naringin ameliorated the motor abnormalities caused by 3-NP, and reduced blood-brain barrier dysfunction by decreasing the expression of matrix metalloproteinases 2 and 9, along with increasing the expression of the tissue inhibitors of metalloproteinases 1 and 2 in 3-NP-induced rats. Further, naringin reduced 3-NP-induced neuroinflammation by decreasing the expression of nuclear factor-kappa B and glial fibrillary acidic protein. Thus, naringin exerts protective effects against 3-NP-induced neurodegeneration by ameliorating the expressions of matrix metalloproteinases and glial fibrillary acidic protein.

Mechanisms underlying the protective effects of myricetin and quercetin following oxygen/glucose deprivation-induced cell swelling and the reduction in glutamate uptake in glial cells

USDA-ARS?s Scientific Manuscript database

C6 glial cells were exposed to oxygen-glucose deprivation (OGD) in cell culture for 5 hr and cell swelling was determined 90 min after the end of OGD. The OGD-induced increase in swelling was significantly blocked by the two flavonoids studied, quercetin and myricetin. The OGD-induced increase in ...

The glial growth factors deficiency and synaptic destabilization hypothesis of schizophrenia.

PubMed

Moises, Hans W; Zoega, Tomas; Gottesman, Irving I

2002-07-03

A systems approach to understanding the etiology of schizophrenia requires a theory which is able to integrate genetic as well as neurodevelopmental factors. Based on a co-localization of loci approach and a large amount of circumstantial evidence, we here propose that a functional deficiency of glial growth factors and of growth factors produced by glial cells are among the distal causes in the genotype-to-phenotype chain leading to the development of schizophrenia. These factors include neuregulin, insulin-like growth factor I, insulin, epidermal growth factor, neurotrophic growth factors, erbB receptors, phosphatidylinositol-3 kinase, growth arrest specific genes, neuritin, tumor necrosis factor alpha, glutamate, NMDA and cholinergic receptors. A genetically and epigenetically determined low baseline of glial growth factor signaling and synaptic strength is expected to increase the vulnerability for additional reductions (e.g., by viruses such as HHV-6 and JC virus infecting glial cells). This should lead to a weakening of the positive feedback loop between the presynaptic neuron and its targets, and below a certain threshold to synaptic destabilization and schizophrenia. Supported by informed conjectures and empirical facts, the hypothesis makes an attractive case for a large number of further investigations. The hypothesis suggests glial cells as the locus of the genes-environment interactions in schizophrenia, with glial asthenia as an important factor for the genetic liability to the disorder, and an increase of prolactin and/or insulin as possible working mechanisms of traditional and atypical neuroleptic treatments.

Intraoperative electroacupuncture relieves remifentanil-induced postoperative hyperalgesia via inhibiting spinal glial activation in rats

PubMed Central

Shi, Changxi; Liu, Yue; Zhang, Wei; Lei, Yishan; Lu, Cui’e; Sun, Rao; Sun, Yu’e; Jiang, Ming; Gu, Xiaoping; Ma, Zhengliang

2017-01-01

Background Accumulating studies have suggested that remifentanil, the widely-used opioid analgesic in clinical anesthesia, can activate the pronociceptive systems and enhance postoperative pain. Glial cells are thought to be implicated in remifentanil-induced hyperalgesia. Electroacupuncture is a complementary therapy to relieve various pain conditions with few side effects, and glial cells may be involved in its antinociceptive effect. In this study, we investigated whether intraoperative electroacupuncture could relieve remifentanil-induced postoperative hyperalgesia by inhibiting the activation of spinal glial cells, the production of spinal proinflammatory cytokines, and the activation of spinal mitogen-activated protein kinases. Methods A rat model of remifentanil-induced postoperative hyperalgesia was used in this study. Electroacupuncture during surgery was conducted at bilateral Zusanli (ST36) acupoints. Behavior tests, including mechanical allodynia and thermal hyperalgesia, were performed at different time points. Astrocytic marker glial fibrillary acidic protein, microglial marker Iba1, proinflammatory cytokines, and phosphorylated mitogen-activated protein kinases in the spinal cord were detected by Western blot and/or immunofluorescence. Results Mechanical allodynia and thermal hyperalgesia were induced by both surgical incision and remifentanil infusion, and remifentanil infusion significantly exaggerated and prolonged incision-induced pronociceptive effects. Glial fibrillary acidic protein, Iba1, proinflammatory cytokines (interleukin-1β and tumor necrosis factor-α), and phosphorylated mitogen-activated protein kinases (p-p38, p-JNK, and p-ERK1/2) were upregulated after surgical incision, remifentanil infusion, and especially after their combination. Intraoperative electroacupuncture significantly attenuated incision- and/or remifentanil-induced pronociceptive effects, spinal glial activation, proinflammatory cytokine upregulation, and phosphorylated mitogen-activated protein kinase upregulation. Conclusions Our study suggests that remifentanil-induced postoperative hyperalgesia can be relieved by intraoperative electroacupuncture via inhibiting the activation of spinal glial cells, the upregulation of spinal proinflammatory cytokines, and the activation of spinal mitogen-activated protein kinases. PMID:28825338

Connecting Malfunctioning Glial Cells and Brain Degenerative Disorders.

PubMed

Kaminsky, Natalie; Bihari, Ofer; Kanner, Sivan; Barzilai, Ari

2016-06-01

The DNA damage response (DDR) is a complex biological system activated by different types of DNA damage. Mutations in certain components of the DDR machinery can lead to genomic instability disorders that culminate in tissue degeneration, premature aging, and various types of cancers. Intriguingly, malfunctioning DDR plays a role in the etiology of late onset brain degenerative disorders such as Parkinson's, Alzheimer's, and Huntington's diseases. For many years, brain degenerative disorders were thought to result from aberrant neural death. Here we discuss the evidence that supports our novel hypothesis that brain degenerative diseases involve dysfunction of glial cells (astrocytes, microglia, and oligodendrocytes). Impairment in the functionality of glial cells results in pathological neuro-glial interactions that, in turn, generate a "hostile" environment that impairs the functionality of neuronal cells. These events can lead to systematic neural demise on a scale that appears to be proportional to the severity of the neurological deficit. Copyright © 2016 The Authors. Production and hosting by Elsevier Ltd.. All rights reserved.

TRPV4 and AQP4 Channels Synergistically Regulate Cell Volume and Calcium Homeostasis in Retinal Müller Glia

PubMed Central

Jo, Andrew O.; Phuong, Tam T.T.; Verkman, Alan S.; Yarishkin, Oleg; MacAulay, Nanna

2015-01-01

Brain edema formation occurs after dysfunctional control of extracellular volume partly through impaired astrocytic ion and water transport. Here, we show that such processes might involve synergistic cooperation between the glial water channel aquaporin 4 (AQP4) and the transient receptor potential isoform 4 (TRPV4), a polymodal swelling-sensitive cation channel. In mouse retinas, TRPV4 colocalized with AQP4 in the end feet and radial processes of Müller astroglia. Genetic ablation of TRPV4 did not affect the distribution of AQP4 and vice versa. However, retinas from Trpv4−/− and Aqp4−/− mice exhibited suppressed transcription of genes encoding Trpv4, Aqp4, and the Kir4.1 subunit of inwardly rectifying potassium channels. Swelling and [Ca2+]i elevations evoked in Müller cells by hypotonic stimulation were antagonized by the selective TRPV4 antagonist HC-067047 (2-methyl-1-[3-(4-morpholinyl)propyl]-5-phenyl-N-[3-(trifluoromethyl)phenyl]-1H-pyrrole-3-carboxamide) or Trpv4 ablation. Elimination of Aqp4 suppressed swelling-induced [Ca2+]i elevations but only modestly attenuated the amplitude of Ca2+ signals evoked by the TRPV4 agonist GSK1016790A [(N-((1S)-1-{[4-((2S)-2-{[(2,4-dichlorophenyl)sulfonyl]amino}-3-hydroxypropanoyl)-1-piperazinyl]carbonyl}-3-methylbutyl)-1-benzothiophene-2-carboxamide]. Glial cells lacking TRPV4 but not AQP4 showed deficits in hypotonic swelling and regulatory volume decrease. Functional synergy between TRPV4 and AQP4 during cell swelling was confirmed in the heterologously expressing Xenopus oocyte model. Importantly, when the swelling rate was osmotically matched for AQP4-positive and AQP4-negative oocytes, TRPV4 activation became independent of AQP4. We conclude that AQP4-mediated water fluxes promote the activation of the swelling sensor, whereas Ca2+ entry through TRPV4 channels reciprocally modulates volume regulation, swelling, and Aqp4 gene expression. Therefore, TRPV4–AQP4 interactions constitute a molecular system that fine-tunes astroglial volume regulation by integrating osmosensing, calcium signaling, and water transport and, when overactivated, triggers pathological swelling. SIGNIFICANCE STATEMENT We characterize the physiological features of interactions between the astroglial swelling sensor transient receptor potential isoform 4 (TRPV4) and the aquaporin 4 (AQP4) water channel in retinal Müller cells. Our data reveal an elegant and complex set of mechanisms involving reciprocal interactions at the level of glial gene expression, calcium homeostasis, swelling, and volume regulation. Specifically, water influx through AQP4 drives calcium influx via TRPV4 in the glial end foot, which regulates expression of Aqp4 and Kir4.1 genes and facilitates the time course and amplitude of hypotonicity-induced swelling and regulatory volume decrease. We confirm the crucial facets of the signaling mechanism in heterologously expressing oocytes. These results identify the molecular mechanism that contributes to dynamic regulation of glial volume but also provide new insights into the pathophysiology of glial reactivity and edema formation. PMID:26424896

Vanadium inhalation induces retinal Müller glial cell (MGC) alterations in a murine model.

PubMed

Cervantes-Yépez, Silvana; López-Zepeda, Lorena Sofía; Fortoul, Teresa I

2018-06-01

Vanadium (V) is a transition metal adhered to suspended particles. Previous studies demonstrated that V inhalation causes oxidative stress in the ependymal epithelium, the choroid plexus on brain lateral ventricles and in the retina. Inhaled-V reaches the eye´s retina through the systemic circulation; however, its effect on the retina has not been widely studied. The Müller glial cell provides support and structure to the retina, facilitates synapses and regulates the microenvironment and neuronal metabolism. Hence, it is of great interest to study the effect of V exposure on the expression and localization of specific biomarkers on this cell. Male CD-1 mice were exposed to V inhalation 1 h/twice/week for 4 and 8-Wk. Expression changes in the retina of Glial fibrillary acidic protein, highly expressed in Müller glial cell when retina is damaged, and Glutamine synthetase, important in preventing excitotoxicity in the retina, were analysed by immunohistochemistry. Glial fibrillary acidic protein expression increased at 4-Wk of V inhalation compared to the control and decreased at 8-Wk of exposure. A time-dependent gradual reduction in glutamine synthetase expression was observed. Changes in glial fibrillary acidic protein expression induced by V suggest retinal damage, whereas glutamine synthetase gradual reduction might indicate that photoreceptors, which produce most of the glutamine synthetase substrate in the retina, are degenerating, probably as a consequence of the oxidative stress induced by V.

Aquaporin 11, a regulator of water efflux at retinal Müller glial cell surface decreases concomitant with immune-mediated gliosis.

PubMed

Deeg, Cornelia A; Amann, Barbara; Lutz, Konstantin; Hirmer, Sieglinde; Lutterberg, Karina; Kremmer, Elisabeth; Hauck, Stefanie M

2016-04-23

Müller glial cells are important regulators of physiological function of retina. In a model disease of retinal inflammation and spontaneous recurrent uveitis in horses (ERU), we could show that retinal Müller glial cells significantly change potassium and water channel protein expression during autoimmune pathogenesis. The most significantly changed channel protein in neuroinflammatory ERU was aquaporin 11 (AQP11). Aquaporins (AQP, 13 members) are important regulators of water and small solute transport through membranes. AQP11 is an unorthodox member of this family and was assigned to a third group of AQPs because of its difference in amino acid sequence (conserved sequence is only 11 %) and especially its largely unknown function. In order to gain insight into the distribution, localization, and function of AQP11 in the retina, we first developed a novel monoclonal antibody for AQP11 enabling quantification, localization, and functional studies. In the horse retina, AQP11 was exclusively expressed at Müller glial cell membranes. In uveitic condition, AQP11 disappeared from gliotic Müller cells concomitant with glutamine synthase. Since function of AQP11 is still under debate, we assessed the impact of AQP11 channel on cell volume regulation of primary Müller glial cells under different osmotic conditions. We conclude a concomitant role for AQP11 with AQP4 in water efflux from these glial cells, which is disturbed in ERU. This could probably contribute to swelling and subsequent severe complication of retinal edema through impaired intracellular fluid regulation. Therefore, AQP11 is important for physiological Müller glia function and the expression pattern and function of this water channel seems to have distinct functions in central nervous system. The significant reduction in neuroinflammation points to a crucial role in pathogenesis of autoimmune uveitis.

Appearance of β-dystroglycan precedes the formation of glio-vascular end-feet in developing rat brain

PubMed Central

Kálmán, Mihály; Oszwald, Erzsébet; Adorján, István

2018-01-01

Dystroglycan has an important role in binding of perivascular glial end-feet to the basal lamina. Its β-subunit is localized in the glial end-feet. The investigation period lasted from E(embryonic day)12 to E20. Laminin and β-dystroglycan were detected by immunohistochemistry, the glial localization of the latter one was supported by electron microscopy. The immature glial structures were visualized by the immunostaining of nestin. The β-dystroglycan immunoreactivity appeared at E16 following the laminin of basal lamina but preceding the perivascular processes of radial glia (E18) and astrocyte-like cells (E20). It occurred in cell bodies which attached to the vessels directly but not with vascular processes and end-feet. The presence of β-dystroglycan in such immature cells may promote their differentiation to perivascular astrocytes and influence the formation of the glio-vascular processes.

Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen

PubMed Central

Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

2013-01-01

Glial calcium (Ca2+) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca2+ waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of adult (8- to 15-week-old) and aging (48- to 80-week-old) ketamine-anesthetized mice after bolus loading with OGB-1/AM and SR101. We report that the occurrence of spontaneous waves is 20 times more frequent in the cerebellar cortex of aging as compared with adult mice, which correlated with a reduction in resting brain oxygen tension. In adult mice, spontaneous glial wave activity increased on reducing resting brain oxygen tension, and ATP-evoked glial waves reduced the tissue O2 tension. Finally, although spontaneous Purkinje cell (PC) activity was not associated with increased glia wave activity, spontaneous glial waves did affect intracellular Ca2+ activity in PCs. The increased wave activity during aging, as well as low resting brain oxygen tension, suggests a relationship between glial waves, brain energy homeostasis, and pathology. PMID:23211964

Restraining reactive oxygen species in Listeria monocytogenes promotes the apoptosis of glial cells.

PubMed

Li, Sen; Li, Yixuan; Chen, Guowei; Zhang, Jingchen; Xu, Fei; Wu, Man

2017-07-01

Listeria monocytogenes is a facultative anaerobic foodborne pathogen that can traverse the blood-brain barrier and cause brain infection. L. monocytogenes infection induces host cell apoptosis in several cell types. In this study, we investigated the apoptosis of human glioma cell line U251 invaded by L. monocytogenes and evaluated the function of bacterial reactive oxygen species (ROS) during infection. Bacterial ROS level was reduced by carrying out treatment with N-acetyl cysteine (NAC) and diphenyleneiodonium chloride (DPI). After infection, the apoptosis of U251 cells was examined by flow cytometry assay and propidium iodide staining. DPI and NAC efficiently decreased ROS level in L. monocytogenes without affecting bacterial growth. Moreover, the apoptosis of glial cells was enhanced upon invasion of DPI- and NAC-pretreated L. monocytogenes. Results indicate that the apoptosis of glial cells can be induced by L. monocytogenes, and that the inhibition of bacterial ROS increases the apoptosis of host cells.

SUMO-1 is associated with a subset of lysosomes in glial protein aggregate diseases.

PubMed

Wong, Mathew B; Goodwin, Jacob; Norazit, Anwar; Meedeniya, Adrian C B; Richter-Landsberg, Christiane; Gai, Wei Ping; Pountney, Dean L

2013-01-01

Oligodendroglial inclusion bodies characterize a subset of neurodegenerative diseases. Multiple system atrophy (MSA) is characterized by α-synuclein glial cytoplasmic inclusions and progressive supranuclear palsy (PSP) is associated with glial tau inclusions. The ubiquitin homologue, SUMO-1, has been identified in inclusion bodies in MSA, located in discrete sub-domains in α-synuclein-positive inclusions. We investigated SUMO-1 associated with oligodendroglial inclusion bodies in brain tissue from MSA and PSP and in glial cell models. We examined MSA and PSP cases and compared to age-matched normal controls. Fluorescence immunohistochemistry revealed frequent SUMO-1 sub-domains within and surrounding inclusions bodies in both diseases and showed punctate co-localization of SUMO-1 and the lysosomal marker, cathepsin D, in affected brain regions. Cell counting data revealed that 70-75 % of lysosomes in inclusion body-positive oligodendrocytes were SUMO-1-positive consistently across MSA and PSP cases, compared to 20 % in neighbouring inclusion body negative oligodendrocytes and 10 % in normal brain tissue. Hsp90 co-localized with some SUMO-1 puncta. We examined the SUMO-1 status of lysosomes in 1321N1 human glioma cells over-expressing α-synuclein and in immortalized rat oligodendrocyte cells over-expressing the four repeat form of tau following treatment with the proteasome inhibitor, MG132. We also transfected 1321N1 cells with the inherently aggregation-prone huntingtin exon 1 mutant, HttQ74-GFP. Each cell model showed the association of SUMO-1-positive lysosomes around focal cytoplasmic accumulations of α-synuclein, tau or HttQ74-GFP, respectively. Association of SUMO-1 with lysosomes was also detected in glial cells bearing α-synuclein aggregates in a rotenone-lesioned rat model. SUMO-1 labelling of lysosomes showed a major increase between 24 and 48 h post-incubation of 1321N1 cells with MG132 resulting in an increase in a 90 kDa SUMO-1-positive band that was immunopositive for Hsp90 and immunoprecipitated with an anti-SUMO-1 antibody. That SUMO-1 co-localizes with a subset of lysosomes in neurodegenerative diseases with glial protein aggregates and in glial cell culture models of protein aggregation suggests a role for SUMO-1 in lysosome function.

The Sleep-inducing Lipid Oleamide Deconvolutes Gap Junction Communication and Calcium Wave Transmission in Glial Cells

PubMed Central

Guan, Xiaojun; Cravatt, Benjamin F.; Ehring, George R.; Hall, James E.; Boger, Dale L.; Lerner, Richard A.; Gilula, Norton B.

1997-01-01

Oleamide is a sleep-inducing lipid originally isolated from the cerebrospinal fluid of sleep-deprived cats. Oleamide was found to potently and selectively inactivate gap junction–mediated communication between rat glial cells. In contrast, oleamide had no effect on mechanically stimulated calcium wave transmission in this same cell type. Other chemical compounds traditionally used as inhibitors of gap junctional communication, like heptanol and 18β-glycyrrhetinic acid, blocked not only gap junctional communication but also intercellular calcium signaling. Given the central role for intercellular small molecule and electrical signaling in central nervous system function, oleamide- induced inactivation of glial cell gap junction channels may serve to regulate communication between brain cells, and in doing so, may influence higher order neuronal events like sleep induction. PMID:9412472

Heterogeneity and phenotypic plasticity of glial cells in the mammalian enteric nervous system.

PubMed

Boesmans, Werend; Lasrado, Reena; Vanden Berghe, Pieter; Pachnis, Vassilis

2015-02-01

Enteric glial cells are vital for the autonomic control of gastrointestinal homeostasis by the enteric nervous system. Several different functions have been assigned to enteric glial cells but whether these are performed by specialized subtypes with a distinctive phenotype and function remains elusive. We used Mosaic Analysis with Double Markers and inducible lineage tracing to characterize the morphology and dynamic molecular marker expression of enteric GLIA in the myenteric plexus. Functional analysis in individually identified enteric glia was performed by Ca(2+) imaging. Our experiments have identified four morphologically distinct subpopulations of enteric glia in the gastrointestinal tract of adult mice. Marker expression analysis showed that the majority of glia in the myenteric plexus co-express glial fibrillary acidic protein (GFAP), S100β, and Sox10. However, a considerable fraction (up to 80%) of glia outside the myenteric ganglia, did not label for these markers. Lineage tracing experiments suggest that these alternative combinations of markers reflect dynamic gene regulation rather than lineage restrictions. At the functional level, the three myenteric glia subtypes can be distinguished by their differential response to adenosine triphosphate. Together, our studies reveal extensive heterogeneity and phenotypic plasticity of enteric glial cells and set a framework for further investigations aimed at deciphering their role in digestive function and disease. © 2014 Wiley Periodicals, Inc.

Pharmacological modulation of spreading depolarizations.

PubMed

Sánchez-Porras, Renán; Zheng, Zelong; Sakowitz, Oliver W

2015-01-01

Spreading depolarization (SD) is a wave of almost complete depolarization of the neuronal and glial cells. Nowadays there is sufficient evidence demonstrating its pathophysiological effect in migraine with aura, transient global amnesia, stroke, subarachnoid hemorrhage, intracerebral hemorrhage, and traumatic brain injury. In these cases, occurrence of SD has been associated with functional neuronal damage, neuronal necrosis, neurological degeneration, and poor clinical outcome. Animal models show that SD can be modulated by drugs that interfere with its initiation and propagation. There are many pharmacological targets that may help to suppress SD occurrence, such as Na⁺, K⁺, Cl⁻, and Ca²⁺ channels; Na⁺/K⁺ -ATPase; gap junctions; and ligand-based receptors, for example, adrenergic, serotonin, sigma-1, calcitonin gene-related peptide, GABAA, and glutamate receptors. In this regard, N-methyl-d-aspartate (NMDA) receptor blockers, in particular, ketamine, have shown promising results. Therefore, theoretically pharmacologic modulation of SD could help diminish its pathological effects.

Molecular Insights into Metabotropic Glutamate Receptor Allosteric Modulation

PubMed Central

Gregory, Karen J.

2015-01-01

The metabotropic glutamate (mGlu) receptors are a group of eight family C G protein–coupled receptors that are expressed throughout the central nervous system (CNS) and periphery. Within the CNS the different subtypes are found in neurons, both pre- and/or postsynaptically, where they mediate modulatory roles and in glial cells. The mGlu receptor family provides attractive targets for numerous psychiatric and neurologic disorders, with the majority of discovery programs focused on targeting allosteric sites, with allosteric ligands now available for all mGlu receptor subtypes. However, the development of allosteric ligands remains challenging. Biased modulation, probe dependence, and molecular switches all contribute to the complex molecular pharmacology exhibited by mGlu receptor allosteric ligands. In recent years we have made significant progress in our understanding of this molecular complexity coupled with an increased understanding of the structural basis of mGlu allosteric modulation. PMID:25808929

Origin, lineage and function of cerebellar glia.

PubMed

Buffo, Annalisa; Rossi, Ferdinando

2013-10-01

The glial cells of the cerebellum, and particularly astrocytes and oligodendrocytes, are characterized by a remarkable phenotypic variety, in which highly peculiar morphological features are associated with specific functional features, unique among the glial cells of the entire CNS. Here, we provide a critical report about the present knowledge of the development of cerebellar glia, including lineage relationships between cerebellar neurons, astrocytes and oligodendrocytes, the origins and the genesis of the repertoire of glial types, and the processes underlying their acquisition of mature morphological and functional traits. In parallel, we describe and discuss some fundamental roles played by specific categories of glial cells during cerebellar development. In particular, we propose that Bergmann glia exerts a crucial scaffolding activity that, together with the organizing function of Purkinje cells, is necessary to achieve the normal pattern of foliation and layering of the cerebellar cortex. Moreover, we discuss some of the functional tasks of cerebellar astrocytes and oligodendrocytes that are distinctive of cerebellar glia throughout the CNS. Notably, we report about the regulation of synaptic signalling in the molecular and granular layer mediated by Bergmann glia and parenchymal astrocytes, and the functional interaction between oligodendrocyte precursor cells and neurons. On the whole, this review provides an extensive overview of the available literature and some novel insights about the origin and differentiation of the variety of cerebellar glial cells and their function in the developing and mature cerebellum. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of neurotrophin-3 on the differentiation of neural stem cells into neurons and oligodendrocytes

PubMed Central

Zhu, Guowei; Sun, Chongran; Liu, Weiguo

2012-01-01

In this study, cells from the cerebral cortex of fetal rats at pregnant 16 days were harvested and cultured with 20 μg/L neurotrophin-3. After 7 days of culture, immunocytochemical staining showed that, 22.4% of cells were positive for nestin, 10.5% were positive for β-III tubulin (neuronal marker), and 60.6% were positive for glial fibrillary acidic protein, but no cells were positive for O4 (oligodendrocytic marker). At 14 days, there were 5.6% nestin-, 9.6% β-III tubulin-, 81.1% glial fibrillary acidic protein-, and 2.2% O4-positive cells. In cells not treated with neurotrophin-3, some were nestin-positive, while the majority showed positive staining for glial fibrillary acidic protein. Our experimental findings indicate that neurotrophin-3 is a crucial factor for inducing neural stem cells differentiation into neurons and oligodendrocytes. PMID:25657683

Glial cell-expressed mechanosensitive channel TRPV4 mediates infrasound-induced neuronal impairment.

PubMed

Shi, Ming; Du, Fang; Liu, Yang; Li, Li; Cai, Jing; Zhang, Guo-Feng; Xu, Xiao-Fei; Lin, Tian; Cheng, Hao-Ran; Liu, Xue-Dong; Xiong, Li-Ze; Zhao, Gang

2013-11-01

Vibroacoustic disease, a progressive and systemic disease, mainly involving the central nervous system, is caused by excessive exposure to low-frequency but high-intensity noise generated by various heavy transportations and machineries. Infrasound is a type of low-frequency noise. Our previous studies demonstrated that infrasound at a certain intensity caused neuronal injury in rats but the underlying mechanism(s) is still largely unknown. Here, we showed that glial cell-expressed TRPV4, a Ca(2+)-permeable mechanosensitive channel, mediated infrasound-induced neuronal injury. Among different frequencies and intensities, infrasound at 16 Hz and 130 dB impaired rat learning and memory abilities most severely after 7-14 days exposure, a time during which a prominent loss of hippocampal CA1 neurons was evident. Infrasound also induced significant astrocytic and microglial activation in hippocampal regions following 1- to 7-day exposure, prior to neuronal apoptosis. Moreover, pharmacological inhibition of glial activation in vivo protected against neuronal apoptosis. In vitro, activated glial cell-released proinflammatory cytokines IL-1β and TNF-α were found to be key factors for this neuronal apoptosis. Importantly, infrasound induced an increase in the expression level of TRPV4 both in vivo and in vitro. Knockdown of TRPV4 expression by siRNA or pharmacological inhibition of TRPV4 in cultured glial cells decreased the levels of IL-1β and TNF-α, attenuated neuronal apoptosis, and reduced TRPV4-mediated Ca(2+) influx and NF-κB nuclear translocation. Finally, using various antagonists we revealed that calmodulin and protein kinase C signaling pathways were involved in TRPV4-triggered NF-κB activation. Thus, our results provide the first evidence that glial cell-expressed TRPV4 is a potential key factor responsible for infrasound-induced neuronal impairment.

IL-18 Contributes to Bone Cancer Pain by Regulating Glia Cells and Neuron Interaction.

PubMed

Liu, Su; Liu, Yue-Peng; Lv, You; Yao, Jun-Li; Yue, Dong-Mei; Zhang, Mao-Yin; Qi, Dun-Yi; Liu, Gong-Jian

2018-02-01

Glial cell hyperactivity has been proposed to be responsible for chronic pain, however, the mechanisms remain unclear. Interleukin (IL)-18, released from glial cells, has been reported to be involved in neuropathic pain. In this study, we investigated the role of IL-18 in bone cancer pain. Bone cancer pain was mimicked by injecting Walker-256 mammary gland carcinoma cells into the intramedullary space of the tibia in rats. Expression and location of IL-18 and the IL-18 receptor were tested. To investigate the contribution of IL-18 signaling to bone cancer pain, IL-18 binding protein and recombinant IL-18 were used. To investigate the mechanisms of glial cells effects, MK801, N-methyl-D-aspartate (NMDA) receptor inhibitor, and Src kinase-specific inhibitor PP1 were used. Tumor cell implantation (TCI) treatment increased expression of IL-18 and IL-18 receptor in spinal cord. The time course of IL-18 upregulation was correlated with TCI-induced pain behaviors. Blocking the IL-18 signaling pathway prevented and reversed bone cancer-related pain behaviors. Meanwhile, blocking IL-18 signaling also suppressed TCI-induced glial cell hyperactivity, as well as activation of GluN2B and subsequent Ca 2+ -dependent signaling. Spinal administration of recombinant IL-18 in naive rat induced significant mechanical allodynia, as well as GluN2B activation. However, intrathecal injection of MK801 failed to suppress recombinant IL-18-induced GluN2B phosphorylation, whereas Src kinase inhibitor PP1 significantly inhibited IL-18-induced GluN2B activation. IL-18-mediated glial-glia and glial-neuron interaction may facilitate bone cancer pain. Blocking IL-18 signaling may effectively prevent and/or suppress bone cancer pain. IL-18 signaling may be a new target for cancer pain therapy. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

A Phenotypic Change But Not Proliferation Underlies Glial Responses in Alzheimer Disease

PubMed Central

Serrano-Pozo, Alberto; Gómez-Isla, Teresa; Growdon, John H.; Frosch, Matthew P.; Hyman, Bradley T.

2014-01-01

Classical immunohistochemical studies in the Alzheimer disease (AD) brain reveal prominent glial reactions, but whether this pathological feature is due primarily to cell proliferation or to a phenotypic change of existing resting cells remains controversial. We performed double-fluorescence immunohistochemical studies of astrocytes and microglia, followed by unbiased stereology-based quantitation in temporal cortex of 40 AD patients and 32 age-matched nondemented subjects. Glial fibrillary acidic protein (GFAP) and major histocompatibility complex II (MHC2) were used as markers of astrocytic and microglial activation, respectively. Aldehyde dehydrogenase 1 L1 and glutamine synthetase were used as constitutive astrocytic markers, and ionized calcium-binding adaptor molecule 1 (IBA1) as a constitutive microglial marker. As expected, AD patients had higher numbers of GFAP+ astrocytes and MHC2+ microglia than the nondemented subjects. However, both groups had similar numbers of total astrocytes and microglia and, in the AD group, these total numbers remained essentially constant over the clinical course of the disease. The GFAP immunoreactivity of astrocytes, but not the MHC2 immunoreactivity of microglia, increased in parallel with the duration of the clinical illness in the AD group. Cortical atrophy contributed to the perception of increased glia density. We conclude that a phenotypic change of existing glial cells, rather than a marked proliferation of glial precursors, accounts for the majority of the glial responses observed in the AD brain. PMID:23602650

The glial growth factors deficiency and synaptic destabilization hypothesis of schizophrenia

PubMed Central

Moises, Hans W; Zoega, Tomas; Gottesman, Irving I

2002-01-01

Background A systems approach to understanding the etiology of schizophrenia requires a theory which is able to integrate genetic as well as neurodevelopmental factors. Presentation of the hypothesis Based on a co-localization of loci approach and a large amount of circumstantial evidence, we here propose that a functional deficiency of glial growth factors and of growth factors produced by glial cells are among the distal causes in the genotype-to-phenotype chain leading to the development of schizophrenia. These factors include neuregulin, insulin-like growth factor I, insulin, epidermal growth factor, neurotrophic growth factors, erbB receptors, phosphatidylinositol-3 kinase, growth arrest specific genes, neuritin, tumor necrosis factor alpha, glutamate, NMDA and cholinergic receptors. A genetically and epigenetically determined low baseline of glial growth factor signaling and synaptic strength is expected to increase the vulnerability for additional reductions (e.g., by viruses such as HHV-6 and JC virus infecting glial cells). This should lead to a weakening of the positive feedback loop between the presynaptic neuron and its targets, and below a certain threshold to synaptic destabilization and schizophrenia. Testing the hypothesis Supported by informed conjectures and empirical facts, the hypothesis makes an attractive case for a large number of further investigations. Implications of the hypothesis The hypothesis suggests glial cells as the locus of the genes-environment interactions in schizophrenia, with glial asthenia as an important factor for the genetic liability to the disorder, and an increase of prolactin and/or insulin as possible working mechanisms of traditional and atypical neuroleptic treatments. PMID:12095426

Formation and spreading of TDP-43 aggregates in cultured neuronal and glial cells demonstrated by time-lapse imaging

PubMed Central

Ishii, Tomohiro; Kawakami, Emiko; Endo, Kentaro; Misawa, Hidemi; Watabe, Kazuhiko

2017-01-01

TAR DNA-binding protein 43 (TDP-43) is a main constituent of cytoplasmic aggregates in neuronal and glial cells in cases of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. We have previously demonstrated that adenovirus-transduced artificial TDP-43 cytoplasmic aggregates formation is enhanced by proteasome inhibition in vitro and in vivo. However, the relationship between cytoplasmic aggregate formation and cell death remains unclear. In the present study, rat neural stem cell lines stably transfected with EGFP- or Sirius-expression vectors under the control of tubulin beta III, glial fibrillary acidic protein, or 2′,3′-cyclic nucleotide 3′-phosphodiesterase promoter were differentiated into neurons, astrocytes, and oligodendrocytes, respectively, in the presence of retinoic acid. The differentiated cells were then transduced with adenoviruses expressing DsRed-tagged human wild type and C-terminal fragment TDP-43 under the condition of proteasome inhibition. Time-lapse imaging analyses revealed growing cytoplasmic aggregates in the transduced neuronal and glial cells, followed by collapse of the cell. The aggregates remained insoluble in culture media, consisted of sarkosyl-insoluble granular materials, and contained phosphorylated TDP-43. Moreover, the released aggregates were incorporated into neighboring neuronal cells, suggesting cell-to-cell spreading. The present study provides a novel tool for analyzing the detailed molecular mechanisms of TDP-43 proteinopathy in vitro. PMID:28599005

The glia of the adult Drosophila nervous system

PubMed Central

Kremer, Malte C.; Jung, Christophe; Batelli, Sara; Rubin, Gerald M.

2017-01-01

Glia play crucial roles in the development and homeostasis of the nervous system. While the GLIA in the Drosophila embryo have been well characterized, their study in the adult nervous system has been limited. Here, we present a detailed description of the glia in the adult nervous system, based on the analysis of some 500 glial drivers we identified within a collection of synthetic GAL4 lines. We find that glia make up ∼10% of the cells in the nervous system and envelop all compartments of neurons (soma, dendrites, axons) as well as the nervous system as a whole. Our morphological analysis suggests a set of simple rules governing the morphogenesis of glia and their interactions with other cells. All glial subtypes minimize contact with their glial neighbors but maximize their contact with neurons and adapt their macromorphology and micromorphology to the neuronal entities they envelop. Finally, glial cells show no obvious spatial organization or registration with neuronal entities. Our detailed description of all glial subtypes and their regional specializations, together with the powerful genetic toolkit we provide, will facilitate the functional analysis of glia in the mature nervous system. GLIA 2017 GLIA 2017;65:606–638 PMID:28133822

Suppression of glutamate-induced excitotoxicity by 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride in rat glial cultures.

PubMed

Kim, Eun-A; Hahn, Hoh-Gyu; Kim, Key-Sun; Kim, Tae Ue; Choi, Soo Young; Cho, Sung-Woo

2010-07-01

We have screened new drugs with a view to developing effective drugs against glutamate-induced excitotoxicity. In the present work, we show effects of a new drug, 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride against glutamate-induced excitotoxicity in primary rat glial cultures. Pretreatment of glial cells with 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride for 2 h significantly protected glial cells against glutamate-induced excitotoxicity in a time- and dose-dependent manner with an optimum concentration of 100 microM. The drug significantly reduced production of proinflammatory cytokines, tumor necrosis factor-alpha, and interlukin-1beta in glutamate-induced excitotoxicity. The drug also prevented glutamate-induced intracellular Ca2+ influx and reduced the subsequent overproduction of nitric oxide and reactive oxygen species. Furthermore, the drug preserved the mitochondrial potential and inhibited the overproduction of cytochrome c. In addition, the drug effectively attenuated the protein level changes of beta-catenin and glycogen synthase kinase-3beta. These results suggest that 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride effectively protected primary cultures of rat glial cells against glutamate-induced excitotoxicity.

The impact of microglial activation on blood-brain barrier in brain diseases

PubMed Central

da Fonseca, Anna Carolina Carvalho; Matias, Diana; Garcia, Celina; Amaral, Rackele; Geraldo, Luiz Henrique; Freitas, Catarina; Lima, Flavia Regina Souza

2014-01-01

The blood-brain barrier (BBB), constituted by an extensive network of endothelial cells (ECs) together with neurons and glial cells, including microglia, forms the neurovascular unit (NVU). The crosstalk between these cells guarantees a proper environment for brain function. In this context, changes in the endothelium-microglia interactions are associated with a variety of inflammation-related diseases in brain, where BBB permeability is compromised. Increasing evidences indicate that activated microglia modulate expression of tight junctions, which are essential for BBB integrity and function. On the other hand, the endothelium can regulate the state of microglial activation. Here, we review recent advances that provide insights into interactions between the microglia and the vascular system in brain diseases such as infectious/inflammatory diseases, epilepsy, ischemic stroke and neurodegenerative disorders. PMID:25404894

PGE2 released by primary sensory neurons modulates Toll-like receptor 4 activities through an EP4 receptor-dependent process.

PubMed

Tse, Kai-Hei; Chow, Kevin B S; Wise, Helen

2016-04-15

Exogenous prostaglandin E2 (PGE2) displays mixed regulatory properties with regard to inflammatory gene expression in dorsal root ganglion (DRG) cells. We show here that endogenously-produced nanomolar concentrations of PGE2, such as that generated in response to Toll-like receptor 4 (TLR4) stimulation, inhibits both cyclooxygenase-2 (COX-2) and tumour necrosis factor alpha (TNFα) mRNA expression in DRG cells in an EP4 receptor-dependent manner. DRG neurons appear to be the major source of PGE2 in the DRG and likely serve as both an autocrine and paracrine system for limiting over-activation of both DRG neurons and glial cells in response to TLR4 stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Calcium-permeable α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptors Trigger Neuronal Nitric-oxide Synthase Activation to Promote Nerve Cell Death in an Src Kinase-dependent Fashion*

PubMed Central

Socodato, Renato; Santiago, Felipe N.; Portugal, Camila C.; Domingues, Ana F.; Santiago, Ana R.; Relvas, João B.; Ambrósio, António F.; Paes-de-Carvalho, Roberto

2012-01-01

In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2′,7′-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-dl-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death. PMID:22992730

Calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors trigger neuronal nitric-oxide synthase activation to promote nerve cell death in an Src kinase-dependent fashion.

PubMed

Socodato, Renato; Santiago, Felipe N; Portugal, Camila C; Domingues, Ana F; Santiago, Ana R; Relvas, João B; Ambrósio, António F; Paes-de-Carvalho, Roberto

2012-11-09

In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-DL-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death.

Stereological analysis of neuron, glial and endothelial cell numbers in the human amygdaloid complex.

PubMed

García-Amado, María; Prensa, Lucía

2012-01-01

Cell number alterations in the amygdaloid complex (AC) might coincide with neurological and psychiatric pathologies with anxiety imbalances as well as with changes in brain functionality during aging. This stereological study focused on estimating, in samples from 7 control individuals aged 20 to 75 years old, the number and density of neurons, glia and endothelial cells in the entire AC and in its 5 nuclear groups (including the basolateral (BL), corticomedial and central groups), 5 nuclei and 13 nuclear subdivisions. The volume and total cell number in these territories were determined on Nissl-stained sections with the Cavalieri principle and the optical fractionator. The AC mean volume was 956 mm(3) and mean cell numbers (x10(6)) were: 15.3 neurons, 60 glial cells and 16.8 endothelial cells. The numbers of endothelial cells and neurons were similar in each AC region and were one fourth the number of glial cells. Analysis of the influence of the individuals' age at death on volume, cell number and density in each of these 24 AC regions suggested that aging does not affect regional size or the amount of glial cells, but that neuron and endothelial cell numbers respectively tended to decrease and increase in territories such as AC or BL. These accurate stereological measures of volume and total cell numbers and densities in the AC of control individuals could serve as appropriate reference values to evaluate subtle alterations in this structure in pathological conditions.

Stereological Analysis of Neuron, Glial and Endothelial Cell Numbers in the Human Amygdaloid Complex

PubMed Central

García-Amado, María; Prensa, Lucía

2012-01-01

Cell number alterations in the amygdaloid complex (AC) might coincide with neurological and psychiatric pathologies with anxiety imbalances as well as with changes in brain functionality during aging. This stereological study focused on estimating, in samples from 7 control individuals aged 20 to 75 years old, the number and density of neurons, glia and endothelial cells in the entire AC and in its 5 nuclear groups (including the basolateral (BL), corticomedial and central groups), 5 nuclei and 13 nuclear subdivisions. The volume and total cell number in these territories were determined on Nissl-stained sections with the Cavalieri principle and the optical fractionator. The AC mean volume was 956 mm3 and mean cell numbers (x106) were: 15.3 neurons, 60 glial cells and 16.8 endothelial cells. The numbers of endothelial cells and neurons were similar in each AC region and were one fourth the number of glial cells. Analysis of the influence of the individuals’ age at death on volume, cell number and density in each of these 24 AC regions suggested that aging does not affect regional size or the amount of glial cells, but that neuron and endothelial cell numbers respectively tended to decrease and increase in territories such as AC or BL. These accurate stereological measures of volume and total cell numbers and densities in the AC of control individuals could serve as appropriate reference values to evaluate subtle alterations in this structure in pathological conditions. PMID:22719923

Choroid plexus carcinoma with neuronal and glial differentiation in a 7-week-old male Sprague-Dawley rat.

PubMed

Inohana, Mari; Eguchi, Ayumi; Nakamura, Misato; Nagahara, Rei; Watanabe, Yosuke; Yoshida, Toshinori; Shibutani, Makoto

2018-04-18

We describe a case of choroid plexus carcinoma arising in the cerebrum of a 7-week-old male Sprague-Dawley rat. The tumor mass occupied the right lateral ventricle of the cerebrum. Histological analyses revealed that the epithelial tumor cells had proliferated in tubular, cribriform, papillary and solid growth patterns in the vicinity of the choroid plexus, with slight invasion into the cerebrum parenchyma. We divided the tumor cells into cuboidal, elongated and intermediate cells. Immunohistochemical studies showed that these tumor cells expressed relatively high levels of cytokeratin AE1/AE3, vimentin and glial fibrillary acidic proteins, and low levels of nestin, oligodendrocyte transcription factor and doublecortin proteins. The present case was diagnosed as a choroid plexus carcinoma with neuronal and glial differentiation.

Nerve growth factor in the adult brain of a teleostean model for aging research: Nothobranchius furzeri.

PubMed

D'Angelo, L; Castaldo, L; Cellerino, A; de Girolamo, P; Lucini, C

2014-07-01

Nerve growth factor (NGF) acts on central nervous system neurons, regulating naturally occurring cell death, synaptic connectivity, fiber guidance and dendritic morphology. The dynamically regulated production of NGF beginning in development, extends throughout adult life and aging, exerting numerous roles through a surprising variety of neurons and glial cells. This study analyzes the localization of NGF in the brain of the teleost fish Nothobranchius furzeri, an emerging model for aging research due to its short lifespan. Immunochemical and immunohistochemical experiments were performed by employing an antibody mapping at the N-terminus of the mature chain human origin NGF. Western blot analysis revealed an intense and well defined band of 20 kDa, which corresponds to proNGF of N. furzeri. Immunohistochemistry revealed NGF immunoreactivity (IR) diffused throughout all regions of telencephalon, diencephalon, mesencephalon and rhomboencephalon. It was detected in neurons and in glial cells, the latter mostly lining the mesencephalic and rhomboencephalic ventricles. Particularly in neurons, NGF IR was localized in perikarya and, to a less extent, in fibers. The widespread distribution of proNGF suggests that it might modulate numerous physiological functions in the adult brain of N. furzeri. The present survey constitutes a baseline study to enhance the understanding of the mechanisms underlying the role of NGF during aging processes. Copyright © 2014 Elsevier GmbH. All rights reserved.

Gemfibrozil, a lipid-lowering drug, induces suppressor of cytokine signaling 3 in glial cells: implications for neurodegenerative disorders.

PubMed

Ghosh, Arunava; Pahan, Kalipada

2012-08-03

Glial inflammation is an important feature of several neurodegenerative disorders. Suppressor of cytokine signaling (SOCS) proteins play a crucial role in inhibiting cytokine signaling and inflammatory gene expression in various cell types, including glial cells. However, mechanisms by which SOCS genes could be up-regulated are poorly understood. This study underlines the importance of gemfibrozil, a Food and Drug Administration-approved lipid-lowering drug, in up-regulating the expression of SOCS3 in glial cells. Gemfibrozil increased the expression of Socs3 mRNA and protein in mouse astroglia and microglia in both a time- and dose-dependent manner. Interestingly, gemfibrozil induced the activation of type IA phosphatidylinositol (PI) 3-kinase and AKT. Accordingly, inhibition of PI 3-kinase and AKT by chemical inhibitors abrogated gemfibrozil-mediated up-regulation of SOCS3. Furthermore, we demonstrated that gemfibrozil induced the activation of Krüppel-like factor 4 (KLF4) via the PI 3-kinase-AKT pathway and that siRNA knockdown of KLF4 abrogated gemfibrozil-mediated up-regulation of SOCS3. Gemfibrozil also induced the recruitment of KLF4 to the distal, but not proximal, KLF4-binding site of the Socs3 promoter. This study delineates a novel property of gemfibrozil in up-regulating SOCS3 in glial cells via PI 3-kinase-AKT-mediated activation of KLF4 and suggests that gemfibrozil may find therapeutic application in neuroinflammatory and neurodegenerative disorders.

Gemfibrozil, a Lipid-lowering Drug, Induces Suppressor of Cytokine Signaling 3 in Glial Cells

PubMed Central

Ghosh, Arunava; Pahan, Kalipada

2012-01-01

Glial inflammation is an important feature of several neurodegenerative disorders. Suppressor of cytokine signaling (SOCS) proteins play a crucial role in inhibiting cytokine signaling and inflammatory gene expression in various cell types, including glial cells. However, mechanisms by which SOCS genes could be up-regulated are poorly understood. This study underlines the importance of gemfibrozil, a Food and Drug Administration-approved lipid-lowering drug, in up-regulating the expression of SOCS3 in glial cells. Gemfibrozil increased the expression of Socs3 mRNA and protein in mouse astroglia and microglia in both a time- and dose-dependent manner. Interestingly, gemfibrozil induced the activation of type IA phosphatidylinositol (PI) 3-kinase and AKT. Accordingly, inhibition of PI 3-kinase and AKT by chemical inhibitors abrogated gemfibrozil-mediated up-regulation of SOCS3. Furthermore, we demonstrated that gemfibrozil induced the activation of Krüppel-like factor 4 (KLF4) via the PI 3-kinase-AKT pathway and that siRNA knockdown of KLF4 abrogated gemfibrozil-mediated up-regulation of SOCS3. Gemfibrozil also induced the recruitment of KLF4 to the distal, but not proximal, KLF4-binding site of the Socs3 promoter. This study delineates a novel property of gemfibrozil in up-regulating SOCS3 in glial cells via PI 3-kinase-AKT-mediated activation of KLF4 and suggests that gemfibrozil may find therapeutic application in neuroinflammatory and neurodegenerative disorders. PMID:22685291

Host/parasite relationship in the in vitro infection of rat gliocytes by Neospora caninum: evaluation of cell respiration.

PubMed

Pinheiro, Alexandre M; Santos, Cláudia Valle; Costa, Maria de Fátima D; Rodrigues, Luiz Erlon A

2007-08-01

Neospora caninum is a protozoon that causes abortion in cattle and neuromuscular lesions in dogs, with the formation of cysts mainly in the central nervous system. Since N. caninum is an intracellular parasite with tropism for the cells of nervous system, this study evaluated the respiratory metabolism of glial cells infected by this* parasite. Glial cultures obtained from the cerebral cortex of newborn rats were kept in DMEM enriched with 10% fetal bovine serum, 1 mM pyruvic acid and 2 mM of L-glutamine. They were infected at a ratio of approximately 1:1 (cell/parasite). Oxygen consumption was evaluated by polarography in the non infected and N. caninum infected groups, 24 and 72 h following infection. Glial cell respiration after 24 and 72 h was 307.2 +/- 34.7 and 308.9 +/- 64.1 microL of oxygen per mug of total protein per minute, and 566.2 +/- 54.6 and 579 +/- 117.5 microL O2/microg of total protein/minute in the control and infected groups, respectively. These results show that N. caninum does not interfere with glial respiration in vitro.

Hydrogel scaffolds promote neural gene expression and structural reorganization in human astrocyte cultures.

PubMed

Knight, V Bleu; Serrano, Elba E

2017-01-01

Biomaterial scaffolds have the potential to enhance neuronal development and regeneration. Understanding the genetic responses of astrocytes and neurons to biomaterials could facilitate the development of synthetic environments that enable the specification of neural tissue organization with engineered scaffolds. In this study, we used high throughput transcriptomic and imaging methods to determine the impact of a hydrogel, PuraMatrix™, on human glial cells in vitro . Parallel studies were undertaken with cells grown in a monolayer environment on tissue culture polystyrene. When the Normal Human Astrocyte (NHA) cell line is grown in a hydrogel matrix environment, the glial cells adopt a structural organization that resembles that of neuronal-glial cocultures, where neurons form clusters that are distinct from the surrounding glia. Statistical analysis of next generation RNA sequencing data uncovered a set of genes that are differentially expressed in the monolayer and matrix hydrogel environments. Functional analysis demonstrated that hydrogel-upregulated genes can be grouped into three broad categories: neuronal differentiation and/or neural plasticity, response to neural insult, and sensory perception. Our results demonstrate that hydrogel biomaterials have the potential to transform human glial cell identity, and may have applications in the repair of damaged brain tissue.

A competitive advantage by neonatally engrafted human glial progenitors yields mice whose brains are chimeric for human glia.

PubMed

Windrem, Martha S; Schanz, Steven J; Morrow, Carolyn; Munir, Jared; Chandler-Militello, Devin; Wang, Su; Goldman, Steven A

2014-11-26

Neonatally transplanted human glial progenitor cells (hGPCs) densely engraft and myelinate the hypomyelinated shiverer mouse. We found that, in hGPC-xenografted mice, the human donor cells continue to expand throughout the forebrain, systematically replacing the host murine glia. The differentiation of the donor cells is influenced by the host environment, such that more donor cells differentiated as oligodendrocytes in the hypomyelinated shiverer brain than in myelin wild-types, in which hGPCs were more likely to remain as progenitors. Yet in each recipient, both the number and relative proportion of mouse GPCs fell as a function of time, concomitant with the mitotic expansion and spread of donor hGPCs. By a year after neonatal xenograft, the forebrain GPC populations of implanted mice were largely, and often entirely, of human origin. Thus, neonatally implanted hGPCs outcompeted and ultimately replaced the host population of mouse GPCs, ultimately generating mice with a humanized glial progenitor population. These human glial chimeric mice should permit us to define the specific contributions of glia to a broad variety of neurological disorders, using human cells in vivo. Copyright © 2014 the authors 0270-6474/14/3416153-09$15.00/0.

Connexin-deficiency affects expression levels of glial glutamate transporters within the cerebrum.

PubMed

Unger, Tina; Bette, Stefanie; Zhang, Jiong; Theis, Martin; Engele, Jürgen

2012-01-06

The glial glutamate transporter subtypes, GLT-1/EAAT-2 and GLAST/EAAT-1 clear the bulk of extracellular glutamate and are severely dysregulated in various acute and chronic brain diseases. Despite the previous identification of several extracellular factors modulating glial glutamate transporter expression, our knowledge of the regulatory network controlling glial glutamate transport in health and disease still remains incomplete. In studies with cultured cortical astrocytes, we previously obtained evidence that glial glutamate transporter expression is also affected by gap junctions/connexins. To assess whether gap junctions would likewise control the in vivo expression of glial glutamate transporters, we have now assessed their expression levels in brains of conditional Cx43 knockout mice, total Cx30 knockouts, as well as Cx43/Cx30 double knockouts. We found that either knocking out Cx30, Cx43, or both increases GLT-1/EAAT-2 protein levels in the cerebral cortex to a similar extent. By contrast, GLAST/EAAT-1 protein levels maximally increased in cerebral cortices of Cx30/Cx43 double knockouts, implying that gap junctions differentially affect the expression of GLT-1/EAAT-2 and GLAST/EAAT-1. Quantitative PCR analysis further revealed that increases in glial glutamate transporter expression are brought about by transcriptional and translational/posttranslational processes. Moreover, GLT-1/EAAT-2- and GLAST/EAAT-1 protein levels remained unchanged in the hippocampi of Cx43/Cx30 double knockouts when compared to Cx43fl/fl controls, indicating brain region-specific effects of gap junctions on glial glutamate transport. Since astrocytic gap junction coupling is affected in various forms of brain injuries, our findings point to gap junctions/connexins as important regulators of glial glutamate turnover in the diseased cerebral cortex. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The Role of NG2 Glial Cells in ALS Pathogenesis

DTIC Science & Technology

2014-12-01

NG2+ glial cells ( OPCs ), NPCs were further differentiated to pre- OPCs and OPCs , outlined in Figure 2, which showed reliable cell morphology and cell...marker expression. Pre- OPCs were determined by their expression of Olig2 and NKX2.2 (Figure 1). The majority of colonies showed Olig2+, NKX2.2...and Olig2+/NKX2.2+ cells, however the percentage of each marker expression varied among colonies. To further differentiate pre- OPCs to OPCs , the

Forebrain engraftment by human glial progenitor cells enhances synaptic plasticity and learning in adult mice.

PubMed

Han, Xiaoning; Chen, Michael; Wang, Fushun; Windrem, Martha; Wang, Su; Shanz, Steven; Xu, Qiwu; Oberheim, Nancy Ann; Bekar, Lane; Betstadt, Sarah; Silva, Alcino J; Takano, Takahiro; Goldman, Steven A; Nedergaard, Maiken

2013-03-07

Human astrocytes are larger and more complex than those of infraprimate mammals, suggesting that their role in neural processing has expanded with evolution. To assess the cell-autonomous and species-selective properties of human glia, we engrafted human glial progenitor cells (GPCs) into neonatal immunodeficient mice. Upon maturation, the recipient brains exhibited large numbers and high proportions of both human glial progenitors and astrocytes. The engrafted human glia were gap-junction-coupled to host astroglia, yet retained the size and pleomorphism of hominid astroglia, and propagated Ca2+ signals 3-fold faster than their hosts. Long-term potentiation (LTP) was sharply enhanced in the human glial chimeric mice, as was their learning, as assessed by Barnes maze navigation, object-location memory, and both contextual and tone fear conditioning. Mice allografted with murine GPCs showed no enhancement of either LTP or learning. These findings indicate that human glia differentially enhance both activity-dependent plasticity and learning in mice. Copyright © 2013 Elsevier Inc. All rights reserved.

Forebrain engraftment by human glial progenitor cells enhances synaptic plasticity and learning in adult mice

PubMed Central

Han, Xiaoning; Chen, Michael; Wang, Fushun; Windrem, Martha; Wang, Su; Shanz, Steven; Xu, Qiwu; Oberheim, Nancy Ann; Bekar, Lane; Betstadt, Sarah; Silva, Alcino J.; Takano, Takahiro; Goldman, Steven A.; Nedergaard, Maiken

2013-01-01

Human astrocytes are larger and more complex than those of infraprimate mammals, suggesting that their role in neural processing has expanded with evolution. To assess the cell-autonomous and species-selective properties of human glia, we engrafted human glial progenitor cells (GPCs) into neonatal immunodeficient mice. Upon maturation, the recipient brains exhibited large numbers and high proportions of both human glial progenitors and astrocytes. The engrafted human glia were gap junction-coupled to host astroglia, yet retained the size and pleomorphism of hominid astroglia, and propagated Ca2+ signals 3-fold faster than their hosts. Long term potentiation (LTP) was sharply enhanced in the human glial chimeric mice, as was their learning, as assessed by Barnes maze navigation, object-location memory, and both contextual and tone fear conditioning. Mice allografted with murine GPCs showed no enhancement of either LTP or learning. These findings indicate that human glia differentially enhance both activity-dependent plasticity and learning in mice. PMID:23472873

Painful purinergic receptors.

PubMed

Donnelly-Roberts, Diana; McGaraughty, Steve; Shieh, Char-Chang; Honore, Prisca; Jarvis, Michael F

2008-02-01

Multiple P2 receptor-mediated mechanisms exist by which ATP can alter nociceptive sensitivity following tissue injury. Evidence from a variety of experimental strategies, including genetic disruption studies and the development of selective antagonists, has indicated that the activation of P2X receptor subtypes, including P2X(3), P2X(2/3), P2X(4) and P2X(7), and P2Y (e.g., P2Y(2)) receptors, can modulate pain. For example, administration of a selective P2X(3) antagonist, A-317491, has been shown to effectively block both hyperalgesia and allodynia in different animal models of pathological pain. Intrathecally delivered antisense oligonucleotides targeting P2X(4) receptors decrease tactile allodynia following nerve injury. Selective antagonists for the P2X(7) receptor also reduce sensitization in animal models of inflammatory and neuropathic pain, providing evidence that purinergic glial-neural interactions are important modulators of noxious sensory neurotransmission. Furthermore, activation of P2Y(2) receptors leads to sensitization of polymodal transient receptor potential-1 receptors. Thus, ATP acting at multiple purinergic receptors, either directly on neurons (e.g., P2X(3), P2X(2/3), and P2Y receptors) or indirectly through neural-glial cell interactions (P2X(4) and P2X(7) receptors), alters nociceptive sensitivity. The development of selective antagonists for some of these P2 receptors has greatly aided investigations into the nociceptive role of ATP. This perspective highlights some of the recent advances to identify selective P2 receptor ligands, which has enhanced the investigation of ATP-related modulation of pain sensitivity.

Cell cycle inhibition limits development and maintenance of neuropathic pain following spinal cord injury

PubMed Central

Wu, Junfang; Zhao, Zaorui; Zhu, Xiya; Renn, Cynthia L.; Dorsey, Susan G.; Faden, Alan I.

2016-01-01

Chronic pain after spinal cord injury (SCI) may present as hyperalgesia, allodynia, and/or spontaneous pain and is often resistant to conventional pain medications. Identifying more effective interventions to manage SCI-Pain requires improved understanding of the pathophysiological mechanisms involved. Cell cycle activation (CCA) has been implicated as a key pathophysiological event following SCI. We have shown that early central or systemic administration of a cell cycle inhibitor reduces CCA, prevents glial changes, and limits SCI-induced hyperesthesia. Here we compared the effects of early versus late treatment with the pan-cyclin dependent kinase inhibitor flavopiridol on allodynia as well as spontaneous pain. Adult C57BL/6 male mice subjected to moderate SCI were treated with intraperitoneal injections of flavopiridol (1 mg/kg), daily for 7 days beginning either 3 h or 5 weeks after injury. Mechanical/thermal allodynia was evaluated, as well as spontaneous pain using the mouse grimace scale (MGS). We show that sensitivity to mechanical and thermal stimulation, and locomotor dysfunction were significantly reduced by early flavopiridol treatment compared to vehicle treated controls. SCI caused robust and extended increases of MGS up to 3 weeks after trauma. Early administration of flavopiridol significantly shortened duration of MGS changes. Late flavopiridol intervention significantly limited hyperesthesia at 7 days after treatment, associated with reduced glial changes, but without effect on locomotion. Thus, our data suggest that cell cycle modulation may provide an effective therapeutic strategy to reduce hyperesthesia after SCI, with a prolonged therapeutic window. PMID:26797506

Adult Mouse DRG Explant and Dissociated Cell Models to Investigate Neuroplasticity and Responses to Environmental Insults Including Viral Infection.

PubMed

Fornaro, Michele; Sharthiya, Harsh; Tiwari, Vaibhav

2018-03-09

This protocol describes an ex vivo model of mouse-derived dorsal root ganglia (DRG) explant and in vitro DRG-derived co-culture of dissociated sensory neurons and glial satellite cells. These are useful and versatile models to investigate a variety of biological responses associated with physiological and pathological conditions of the peripheral nervous system (PNS) ranging from neuron-glial interaction, neuroplasticity, neuroinflammation, and viral infection. The usage of DRG explant is scientifically advantageous compared to simplistic single cells models for multiple reasons. For instance, as an organotypic culture, the DRG explant allows ex vivo transfer of an entire neuronal network including the extracellular microenvironment that play a significant role in all the neuronal and glial functions. Further, DRG explants can also be maintained ex vivo for several days and the culture conditions can be perturbed as desired. In addition, the harvested DRG can be further dissociated into an in vitro co-culture of primary sensory neurons and satellite glial cells to investigate neuronal-glial interaction, neuritogenesis, axonal cone interaction with the extracellular microenvironment, and more general, any aspect associated with the neuronal metabolism. Therefore, the DRG-explant system offers a great deal of flexibility to study a wide array of events related to biological, physiological, and pathological conditions in a cost-effective manner.

Clinical Findings Documenting Cellular and Molecular Abnormalities of Glia in Depressive Disorders

PubMed Central

Czéh, Boldizsár; Nagy, Szilvia A.

2018-01-01

Depressive disorders are complex, multifactorial mental disorders with unknown neurobiology. Numerous theories aim to explain the pathophysiology. According to the “gliocentric theory”, glial abnormalities are responsible for the development of the disease. The aim of this review article is to summarize the rapidly growing number of cellular and molecular evidences indicating disturbed glial functioning in depressive disorders. We focus here exclusively on the clinical studies and present the in vivo neuroimaging findings together with the postmortem molecular and histopathological data. Postmortem studies demonstrate glial cell loss while the in vivo imaging data reveal disturbed glial functioning and altered white matter microstructure. Molecular studies report on altered gene expression of glial specific genes. In sum, the clinical findings provide ample evidences on glial pathology and demonstrate that all major glial cell types are affected. However, we still lack convincing theories explaining how the glial abnormalities develop and how exactly contribute to the emotional and cognitive disturbances. Abnormal astrocytic functioning may lead to disturbed metabolism affecting ion homeostasis and glutamate clearance, which in turn, affect synaptic communication. Abnormal oligodendrocyte functioning may disrupt the connectivity of neuronal networks, while microglial activation indicates neuroinflammatory processes. These cellular changes may relate to each other or they may indicate different endophenotypes. A theory has been put forward that the stress-induced inflammation—mediated by microglial activation—triggers a cascade of events leading to damaged astrocytes and oligodendroglia and consequently to their dysfunctions. The clinical data support the “gliocentric” theory, but future research should clarify whether these glial changes are truly the cause or simply the consequences of this devastating disorder. PMID:29535607

Physical and Functional Interaction of NCX1 and EAAC1 Transporters Leading to Glutamate-Enhanced ATP Production in Brain Mitochondria

PubMed Central

Arcangeli, Sara; Nasti, Annamaria Assunta; Giordano, Antonio; Amoroso, Salvatore

2012-01-01

Glutamate is emerging as a major factor stimulating energy production in CNS. Brain mitochondria can utilize this neurotransmitter as respiratory substrate and specific transporters are required to mediate the glutamate entry into the mitochondrial matrix. Glutamate transporters of the Excitatory Amino Acid Transporters (EAATs) family have been previously well characterized on the cell surface of neuronal and glial cells, representing the primary players for glutamate uptake in mammalian brain. Here, by using western blot, confocal microscopy and immunoelectron microscopy, we report for the first time that the Excitatory Amino Acid Carrier 1 (EAAC1), an EAATs member, is expressed in neuronal and glial mitochondria where it participates in glutamate-stimulated ATP production, evaluated by a luciferase-luciferin system. Mitochondrial metabolic response is counteracted when different EAATs pharmacological blockers or selective EAAC1 antisense oligonucleotides were used. Since EAATs are Na+-dependent proteins, this raised the possibility that other transporters regulating ion gradients across mitochondrial membrane were required for glutamate response. We describe colocalization, mutual activity dependency, physical interaction between EAAC1 and the sodium/calcium exchanger 1 (NCX1) both in neuronal and glial mitochondria, and that NCX1 is an essential modulator of this glutamate transporter. Only NCX1 activity is crucial for such glutamate-stimulated ATP synthesis, as demonstrated by pharmacological blockade and selective knock-down with antisense oligonucleotides. The EAAC1/NCX1-dependent mitochondrial response to glutamate may be a general and alternative mechanism whereby this neurotransmitter sustains ATP production, since we have documented such metabolic response also in mitochondria isolated from heart. The data reported here disclose a new physiological role for mitochondrial NCX1 as the key player in glutamate-induced energy production. PMID:22479505

Rho kinase inhibition following traumatic brain injury in mice promotes functional improvement and acute neuron survival but has little effect on neurogenesis, glial responses or neuroinflammation.

PubMed

Bye, Nicole; Christie, Kimberly J; Turbic, Alisa; Basrai, Harleen S; Turnley, Ann M

2016-05-01

Inhibition of the Rho/Rho kinase pathway has been shown to be beneficial in a variety of neural injuries and diseases. In this manuscript we investigate the role of Rho kinase inhibition in recovery from traumatic brain injury using a controlled cortical impact model in mice. Mice subjected to a moderately severe TBI were treated for 1 or 4 weeks with the Rho kinase inhibitor Y27632, and functional outcomes and neuronal and glial cell responses were analysed at 1, 7 and 35 days post-injury. We hypothesised that Y27632-treated mice would show functional improvement, with augmented recruitment of neuroblasts from the SVZ and enhanced survival of newborn neurons in the pericontusional cortex, with protection against neuronal degeneration, neuroinflammation and modulation of astrocyte reactivity and blood-brain-barrier permeability. While Rho kinase inhibition enhanced recovery of motor function after trauma, there were no substantial increases in the recruitment of DCX(+) neuroblasts or the number of BrdU(+) or EdU(+) labelled newborn neurons in the pericontusional cortex of Y27632-treated mice. Inhibition of Rho kinase significantly reduced the number of degenerating cortical neurons at 1day post-injury compared to saline controls but had no longer term effect on neuronal degeneration, with only modest effects on astrocytic reactivity and macrophage/microglial responses. Overall, this study showed that Rho kinase contributes to acute neurodegenerative processes in the injured cortex but does not play a significant role in SVZ neural precursor cell-derived adult neurogenesis, glial responses or blood-brain barrier permeability following a moderately severe brain injury. Copyright © 2016 Elsevier Inc. All rights reserved.

Genetic defects disrupting glial ion and water homeostasis in the brain.

PubMed

Min, Rogier; van der Knaap, Marjo S

2018-05-01

Electrical activity of neurons in the brain, caused by the movement of ions between intracellular and extracellular compartments, is the basis of all our thoughts and actions. Maintaining the correct ionic concentration gradients is therefore crucial for brain functioning. Ion fluxes are accompanied by the displacement of osmotically obliged water. Since even minor brain swelling leads to severe brain damage and even death, brain ion and water movement has to be tightly regulated. Glial cells, in particular astrocytes, play a key role in ion and water homeostasis. They are endowed with specific channels, pumps and carriers to regulate ion and water flow. Glial cells form a large panglial syncytium to aid the uptake and dispersal of ions and water, and make extensive contacts with brain fluid barriers for disposal of excess ions and water. Genetic defects in glial proteins involved in ion and water homeostasis disrupt brain functioning, thereby leading to neurological diseases. Since white matter edema is often a hallmark disease feature, many of these diseases are characterized as leukodystrophies. In this review we summarize our current understanding of inherited glial diseases characterized by disturbed brain ion and water homeostasis by integrating findings from MRI, genetics, neuropathology and animal models for disease. We discuss how mutations in different glial proteins lead to disease, and highlight the similarities and differences between these diseases. To come to effective therapies for this group of diseases, a better mechanistic understanding of how glial cells shape ion and water movement in the brain is crucial. © 2018 The Authors. Brain Pathology published by John Wiley & Sons Ltd on behalf of International Society of Neuropathology.

Identification of two novel glial-restricted cell populations in the embryonic telencephalon arising from unique origins

PubMed Central

Strathmann, Frederick G; Wang, Xi; Mayer-Pröschel, Margot

2007-01-01

Background Considerably less attention has been given to understanding the cellular components of gliogenesis in the telencephalon when compared to neuronogenesis, despite the necessity of normal glial cell formation for neurological function. Early proposals of exclusive ventral oligodendrocyte precursor cell (OPC) generation have been challenged recently with studies revealing the potential of the dorsal telencephalon to also generate oligodendrocytes. The identification of OPCs generated from multiple regions of the developing telencephalon, together with the need of the embryonic telencephalon to provide precursor cells for oligodendrocytes as well as astrocytes in ventral and dorsal areas, raises questions concerning the identity of the precursor cell populations capable of generating macroglial subtypes during multiple developmental windows and in differing locations. Results We have identified progenitor populations in the ventral and dorsal telencephalon restricted to the generation of astrocytes and oligodendrocytes. We further demonstrate that the dorsal glial progenitor cells can be generated de novo from the dorsal telencephalon and we demonstrate their capacity for in vivo production of both myelin-forming oligodendrocytes and astrocytes upon transplantation. Conclusion Based on our results we offer a unifying model of telencephalic gliogenesis, with the generation of both oligodendrocytes and astrocytes from spatially separate, but functionally similar, glial restricted populations at different developmental times in the dorsal and ventral CNS. PMID:17439658

Understanding direct neuronal reprogramming-from pioneer factors to 3D chromatin.

PubMed

Ninkovic, Jovica; Götz, Magdalena

2018-06-14

Cell replacement therapies aim at reestablishment of neuronal circuits after brain injury, stroke or neurodegeneration. Recently, direct reprogramming of resident glial cells into the affected neuronal subtypes has become a feasible and promising option for central nervous system regeneration. Direct reprogramming relies on the implementation of a new transcriptional program defining the desired neuronal identity in fully differentiated glial cells implying the more or less complete down-regulation of the program for the former identity of the glial cell. Despite the enormous progress achieved in this regard with highly efficient in vivo reprogramming after injury, a number of hurdles still need to be resolved. One way to further improve direct neuronal reprogramming is to understand the molecular hurdles which we discuss with the focus on chromatin states of the starting versus the reprogrammed cells. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stem cells for the treatment of neurological disorders

NASA Astrophysics Data System (ADS)

Lindvall, Olle; Kokaia, Zaal

2006-06-01

Many common neurological disorders, such as Parkinson's disease, stroke and multiple sclerosis, are caused by a loss of neurons and glial cells. In recent years, neurons and glia have been generated successfully from stem cells in culture, fuelling efforts to develop stem-cell-based transplantation therapies for human patients. More recently, efforts have been extended to stimulating the formation and preventing the death of neurons and glial cells produced by endogenous stem cells within the adult central nervous system. The next step is to translate these exciting advances from the laboratory into clinically useful therapies.

Social Behavior in Medulloblastoma: Functional Analysis of Tumor-Supporting Glial Cells

DTIC Science & Technology

2012-07-01

AD_________________ Award Number: W81XWH-11-1-0557 TITLE: Social behavior in medulloblastoma ...1 July 2011 – 30 June 2012 4. TITLE AND SUBTITLE Social behavior in medulloblastoma : functional analysis of tumor-supporting glial cells 5a...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Medulloblastoma is the most common malignant pediatric brain tumor. Granule neuron precursors

Social Behavior in Medulloblastoma: Functional Analysis of Tumor-Supporting Glial Cells

DTIC Science & Technology

2014-07-01

AD_________________ Award Number: W81XWH-11-1-0557 TITLE: Social behavior in Medulloblastoma ... Medulloblastoma : Functional Analysis of Tumor-Supporting 5a. CONTRACT NUMBER Glial Cells 5b. GRANT NUMBER W81XWH-11-1-0557 5c. PROGRAM ELEMENT...AVAILABILITY STATEMENT Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Medulloblastoma is the

Pleiotropic function of TRPV4 ion channels in the central nervous system

PubMed Central

Kanju, Patrick; Liedtke, Wolfgang

2016-01-01

TRPV4 ion channels are osmo-mechano-TRP channels with pleiotropic function and expression in many different types of tissues and cells. They have also been found involved in pain and inflammation. Studies have focused on the role of TRPV4 in peripheral sensory neurons, but its expression and function in central nervous glial cells and neurons has also been documented. In this overview, based on the senior author’s lecture at the recent physiology meeting in Dublin, we concisely review evidence of TRPV4 expression and function in the CNS, and how TRPV4 function can be modulated for therapeutic benefit of neuro-psychiatric disorders. Novel TRPV4-inhibitory compounds developed recently in the authors’ lab will also be discussed PMID:27701788

A Systems Level, Functional Genomics Analysis of Chronic Epilepsy

PubMed Central

Bragin, Anatol; Kudo, Lili C.; Gehman, Lauren; Ruidera, Josephine; Geschwind, Daniel H.; Engel, Jerome

2011-01-01

Neither the molecular basis of the pathologic tendency of neuronal circuits to generate spontaneous seizures (epileptogenicity) nor anti-epileptogenic mechanisms that maintain a seizure-free state are well understood. Here, we performed transcriptomic analysis in the intrahippocampal kainate model of temporal lobe epilepsy in rats using both Agilent and Codelink microarray platforms to characterize the epileptic processes. The experimental design allowed subtraction of the confounding effects of the lesion, identification of expression changes associated with epileptogenicity, and genes upregulated by seizures with potential homeostatic anti-epileptogenic effects. Using differential expression analysis, we identified several hundred expression changes in chronic epilepsy, including candidate genes associated with epileptogenicity such as Bdnf and Kcnj13. To analyze these data from a systems perspective, we applied weighted gene co-expression network analysis (WGCNA) to identify groups of co-expressed genes (modules) and their central (hub) genes. One such module contained genes upregulated in the epileptogenic region, including multiple epileptogenicity candidate genes, and was found to be involved the protection of glial cells against oxidative stress, implicating glial oxidative stress in epileptogenicity. Another distinct module corresponded to the effects of chronic seizures and represented changes in neuronal synaptic vesicle trafficking. We found that the network structure and connectivity of one hub gene, Sv2a, showed significant changes between normal and epileptogenic tissue, becoming more highly connected in epileptic brain. Since Sv2a is a target of the antiepileptic levetiracetam, this module may be important in controlling seizure activity. Bioinformatic analysis of this module also revealed a potential mechanism for the observed transcriptional changes via generation of longer alternatively polyadenlyated transcripts through the upregulation of the RNA binding protein HuD. In summary, combining conventional statistical methods and network analysis allowed us to interpret the differentially regulated genes from a systems perspective, yielding new insight into several biological pathways underlying homeostatic anti-epileptogenic effects and epileptogenicity. PMID:21695113

The cells of cajal-retzius: still a mystery one century after.

PubMed

Soriano, Eduardo; Del Río, José Antonio

2005-05-05

Cajal-Retzius (CR) cells are an enigmatic class of neurons located at the surface of the cerebral cortex, playing a major role in cortical development. In this review, we discuss several distinct features of these neurons and the mechanisms by which they regulate cortical development. Many CR cells likely have extracortical origin and undergo cell death during development. Recent genetic studies report unique patterns of gene expression in CR cells, which may help to explain the developmental processes in which they participate. Moreover, a number of studies indicate that CR cells, and their secreted gene product, reelin, are involved in neuronal migration by acting on two key partners, migrating neurons and radial glial cells. Emerging data show that these neurons are a critical part of an early and complex network of neural activity in layer I, supporting the notion that CR cells modulate cortical maturation. Given these key and complex developmental properties, it is therefore conceivable for CR cells to be implicated in the pathogenesis of a variety of neurological disorders.

Short-term block of Na+/K+-ATPase in neuro-glial cell cultures of cerebellum induces glutamate dependent damage of granule cells.

PubMed

Stelmashook, E V; Weih, M; Zorov, D; Victorov, I; Dirnagl, U; Isaev, N

1999-07-30

Granule cells in a dissociated neuro-glial cell culture of cerebellum when exposed to ouabain (10(-3) M) for 25 min apparently swell, increase their [Ca2+]i with obvious depolarization of the mitochondrial membrane. In 3 h after ouabain was omitted from the solution, 62 +/- 3% of granule cells had pycnotic nuclei. The supplement of a solution with competitive specific antagonist of NMDA receptors, L-2-amino-7-phosphonoheptanoate (10(-4) M, APH) together with ouabain prevented cells from swelling, mitochondrial deenergization, neuronal death and increase of [Ca2+]i. These data suggest that cellular Na+/K+-ATPase inactivation in neuro-glial cell cultures of cerebellum leads to glutamate (Glu) accumulation, hyperstimulation of glutamate receptors, higher Ca2+ and Na+ influxes into the cells through the channels activated by Glu. This process leads to cell swelling, mitochondrial deenergization and death of granule cells. Possibly, the decrease of Na+/K+-ATPase activity in brain cells can lead to the onset of at least some chronic neurological disorders.

Neuron-Glia Crosstalk and Neuropathic Pain: Involvement in the Modulation of Motor Activity in the Orofacial Region.

PubMed

Hossain, Mohammad Zakir; Unno, Shumpei; Ando, Hiroshi; Masuda, Yuji; Kitagawa, Junichi

2017-09-26

Neuropathic orofacial pain (NOP) is a debilitating condition. Although the pathophysiology remains unclear, accumulating evidence suggests the involvement of multiple mechanisms in the development of neuropathic pain. Recently, glial cells have been shown to play a key pathogenetic role. Nerve injury leads to an immune response near the site of injury. Satellite glial cells are activated in the peripheral ganglia. Various neural and immune mediators, released at the central terminals of primary afferents, lead to the sensitization of postsynaptic neurons and the activation of glia. The activated glia, in turn, release pro-inflammatory factors, further sensitizing the neurons, and resulting in central sensitization. Recently, we observed the involvement of glia in the alteration of orofacial motor activity in NOP. Microglia and astroglia were activated in the trigeminal sensory and motor nuclei, in parallel with altered motor functions and a decreased pain threshold. A microglial blocker attenuated the reduction in pain threshold, reduced the number of activated microglia, and restored motor activity. We also found an involvement of the astroglial glutamate-glutamine shuttle in the trigeminal motor nucleus in the alteration of the jaw reflex. Neuron-glia crosstalk thus plays an important role in the development of pain and altered motor activity in NOP.

Neuron–Glia Crosstalk and Neuropathic Pain: Involvement in the Modulation of Motor Activity in the Orofacial Region

PubMed Central

Unno, Shumpei; Ando, Hiroshi; Masuda, Yuji; Kitagawa, Junichi

2017-01-01

Neuropathic orofacial pain (NOP) is a debilitating condition. Although the pathophysiology remains unclear, accumulating evidence suggests the involvement of multiple mechanisms in the development of neuropathic pain. Recently, glial cells have been shown to play a key pathogenetic role. Nerve injury leads to an immune response near the site of injury. Satellite glial cells are activated in the peripheral ganglia. Various neural and immune mediators, released at the central terminals of primary afferents, lead to the sensitization of postsynaptic neurons and the activation of glia. The activated glia, in turn, release pro-inflammatory factors, further sensitizing the neurons, and resulting in central sensitization. Recently, we observed the involvement of glia in the alteration of orofacial motor activity in NOP. Microglia and astroglia were activated in the trigeminal sensory and motor nuclei, in parallel with altered motor functions and a decreased pain threshold. A microglial blocker attenuated the reduction in pain threshold, reduced the number of activated microglia, and restored motor activity. We also found an involvement of the astroglial glutamate–glutamine shuttle in the trigeminal motor nucleus in the alteration of the jaw reflex. Neuron–glia crosstalk thus plays an important role in the development of pain and altered motor activity in NOP. PMID:28954391

Intradiencephalon injection of histamine inhibited the recovery of locomotor function of spinal cord injured zebrafish.

PubMed

Huang, Shu-Bing; Zhao, Hou-De; Wang, Lin-Fang; Sun, Meng-Fei; Zhu, Ying-Li; Wu, Yi-Bo; Xu, Yi-Da; Peng, Shi-Xiao; Cui, Chun; Shen, Yan-Qin

2017-07-29

Human spinal cord injury (SCI) usually causes irreversible disability beneath the injured site due to poor neural regeneration. On the contrary, zebrafish show significant regenerative ability after SCI, thus is usually worked as an animal model for studying neuroregeneration. Most of the previous SCI studies focused on the local site of SCI, the supraspinal-derived signals were rarely mentioned. Here we showed that intradiencephalon injection of histamine (HA) inhibited the locomotor recovery in adult zebrafish post-SCI. Immunofluorescence results showed that intradiencephalon HA administration increased the activated microglia 3 days post injury (dpi), promoted the proliferation of radial glial cells at 7 dpi and affected the morphology of radial glial cells at 11 dpi. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) results showed that intradiencephalon HA administration also reduced the expression of neurotrophic factors including brain-derived neurotrophic factor (BDNF) and insulin-like growth factor1 (IGF-1) at the lesion site, however, had no effect on the expression of pro-inflammatory factors such as TNF-alpha and IL-1 beta. Hence, our data suggested that exogenous intradiencephalon HA retarded locomotor recovery in spinal cord injured zebrafish via modulating the repair microenvironment. Copyright © 2017 Elsevier Inc. All rights reserved.

Pineal gland function is required for colon antipreneoplastic effects of physical exercise in rats.

PubMed

Frajacomo, F T T; de Paula Garcia, W; Fernandes, C R; Garcia, S B; Kannen, V

2015-10-01

Light-at-night exposure enhances the risk of cancer. Colon cancer is among the most dangerous tumors affecting humankind. Physical exercise has shown positive effects against colon cancer. Here, we investigated whether pineal gland modulates antipreneoplastic effects of physical exercise in the colon. Surgical and non-surgical pineal impairments were performed to clarify the relationship between the pineal gland activity and manifestation of colonic preneoplastic lesions. Next, a progressive swimming training was applied in rats exposed or not to either non-surgical pineal impairment or carcinogen treatment for 10 weeks. Both surgical and non-surgical pineal impairments increased the development of colon preneoplasia. It was further found that impairing the pineal gland function, higher rates of DNA damage were induced in colonic epithelial and enteric glial cells. Physical exercise acted positively against preneoplasia, whereas impairing the pineal function with constant light exposure disrupts its positive effects on the development of preneoplastic lesions in the colon. This was yet related to increased DNA damage in glial cells and enteric neuronal activation aside from serum melatonin levels. Our findings suggest that protective effects of physical exercise against colon cancer are dependent on the pineal gland activity. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Pediatric Glial Heterotopia in the Medial Canthus.

PubMed

Kim, Soung Min; Amponsah, Emmanuel Kofi; Eo, Mi Young; Cho, Yun Ju; Lee, Suk Keun

2017-11-01

Glial heterotopias are rare, benign, congenital, midline, and nonteratomatous extracranial glial tissue. They may be confused as encephalocele or dermoid cysts and are mostly present in the nose.An 8-month-old African female child presented with a slow growing paranasal mass. The mass had been present at the left upper medial canthus since birth and had slowly and progressively enlarged. There was no communication between the mass and the cranial cavity during the operational procedure. The mass was immunohistochemically positive for S-100 protein as well as for glial fibrillary acidic protein, but negative for proliferating cell nuclear antigen. This suggested that the mass was composed of benign glial tissues with many astrocytes.The purpose of this report is to demonstrate the first patient with pediatric glial heterotopic tissue in the medial canthus and to report the clinical importance of its immunohistochemical findings.

N-CADHERIN MEDIATES NITRIC OXIDE-INDUCED NEUROGENESIS IN YOUNG AND RETIRED BREEDER NEUROSPHERES

PubMed Central

CHEN, J.; ZACHAREK, A.; LI, Y.; LI, A.; WANG, L.; KATAKOWSKI, M.; ROBERTS, C.; LU, M.; CHOPP, M.

2009-01-01

Neurogenesis may contribute to functional recovery after neural injury. Nitric oxide donors such as DETA-NONOate promote functional recovery after stroke. However, the mechanisms underlying functional improvement have not been ascertained. We therefore investigated the effects of DETA-NONOate on neural progenitor/stem cell neurospheres derived from the subventricular zone from young and retired breeder rat brain. Subventricular zone cells were dissociated from normal young adult male Wistar rats (2–3 months old) and retired breeder rats (14 months old), treated with or without DETA-NONOate. Subventricular zone neurosphere formation, proliferation, telomerase activity, and Neurogenin 1 mRNA expression were significantly decreased and glial fibrillary acidic protein expression was significantly increased in subventricular zone neurospheres from retired breeder rats compared with young rats. Treatment of neurospheres with DETA-NONOate significantly decreased neurosphere formation and telomerase activity, and promoted neuronal differentiation and neurite outgrowth concomitantly with increased N-cadherin and β-catenin mRNA expression in both young and old neurospheres. DETA-NONOate selectively increased Neurogenin 1 and decreased glial fibrillary acidic protein mRNA expression in retired breeder neurospheres. N-cadherin significantly increased Neurogenin 1 mRNA expression in young and old neurospheres. Anti-N-cadherin reversed DETA-NONOate-induced neurosphere adhesion, neuronal differentiation, neurite outgrowth, and β-catenin mRNA expression. Our data indicate that age has a potent effect on the characteristics of subventricular zone neurospheres; neurospheres from young rats show significantly higher formation, proliferation and telomerase activity than older neurospheres. In contrast, older neurospheres exhibit significantly increased glial differentiation than young neurospheres. DETA-NONOate promotes neuronal differentiation and neurite outgrowth in both young and older neurospheres. The molecular mechanisms associated with the DETA-NONOate modulation of neurospheres from young and older animals as well age dependent effects of neurospheres appear to be controlled by N-cadherin and β-catenin gene expression, which subsequently regulates the neuronal differentiating factor Neurogenin expression in both young and old neural progenitor cells. PMID:16580782

Glial glycine transporter 1 function is essential for early postnatal survival but dispensable in adult mice.

PubMed

Eulenburg, Volker; Retiounskaia, Marina; Papadopoulos, Theofilos; Gomeza, Jesús; Betz, Heinrich

2010-07-01

The glycine transporter 1 (GlyT1) is expressed in astrocytes and selected neurons of the mammalian CNS. In newborn mice, GlyT1 is crucial for efficient termination of glycine-mediated inhibitory neurotransmission. Furthermore, GlyT1 has been implicated in the regulation of excitatory N-methyl-D-asparate (NMDA) receptors. To evaluate whether glial and neuronal GlyT1 have distinct roles at inhibitory synapses, we inactivated the GlyT1 gene cell type-specifically using mice carrying floxed GlyT1 alleles GlyT1((+)/+)). GlyT1((+)/(+)) mice expressing Cre recombinase in glial cells developed severe neuromotor deficits during the first postnatal week, which mimicked the phenotype of conventional GlyT1 knock-out mice and are consistent with glycinergic over-inhibition. In contrast, Cre-mediated inactivation of the GlyT1 gene in neuronal cells did not result in detectable motor impairment. Notably, some animals deficient for glial GlyT1 survived the first postnatal week and did not develop neuromotor deficits throughout adulthood, although GlyT1 expression was efficiently reduced. Thus, glial GlyT1 is critical for the regulation of glycine levels at inhibitory synapses only during early postnatal life. Copyright 2010 Wiley-Liss, Inc.

Is gliomatosis peritonei derived from the associated ovarian teratoma?

PubMed

Kwan, Man-Yee; Kalle, Wouter; Lau, Gene T C; Chan, John K C

2004-06-01

Gliomatosis peritonei, a rare condition that occurs almost exclusively in the setting of ovarian immature teratoma, is characterized by the occurrence of nodules of mature glial tissues in the peritoneum. It is controversial whether glial tissues are derived from maturation of the associated teratomatous tissue that has implanted in the peritoneum, or glial differentiation of subperitoneal stem cells. In this study, we employed the unique genetic characteristics of ovarian teratomas (often with a duplicated set of maternal chromosomes and thus homozygous at many polymorphic microsatellite loci) versus normal tissues (heterozygous pattern due to presence of maternal and paternal genetic materials) to investigate the origin of gliomatosis peritonei. DNA samples were extracted from microdissected paraffin-embedded tissues, including the glial implants, the associated ovarian teratomas, and normal tissues, to determine their patterns of microsatellite loci in a multiplex polymerase chain reaction system. Two cases were not informative because the ovarian teratoma showed a heterozygous microsatellite pattern. In the 5 informative cases, the normal tissues showed a heterozygous pattern in the microsatellite loci, the associated teratomas showed a homozygous pattern, and the glial tissues showed a heterozygous pattern. Thus, gliomatosis peritonei is genetically unrelated to the associated teratoma but is probably derived from nonteratomatous cells, such as through metaplasia of submesothelial cells.

Disrupting MLC1 and GlialCAM and ClC-2 interactions in leukodystrophy entails glial chloride channel dysfunction

NASA Astrophysics Data System (ADS)

Hoegg-Beiler, Maja B.; Sirisi, Sònia; Orozco, Ian J.; Ferrer, Isidre; Hohensee, Svea; Auberson, Muriel; Gödde, Kathrin; Vilches, Clara; de Heredia, Miguel López; Nunes, Virginia; Estévez, Raúl; Jentsch, Thomas J.

2014-03-01

Defects in the astrocytic membrane protein MLC1, the adhesion molecule GlialCAM or the chloride channel ClC-2 underlie human leukoencephalopathies. Whereas GlialCAM binds ClC-2 and MLC1, and modifies ClC-2 currents in vitro, no functional connections between MLC1 and ClC-2 are known. Here we investigate this by generating loss-of-function Glialcam and Mlc1 mouse models manifesting myelin vacuolization. We find that ClC-2 is unnecessary for MLC1 and GlialCAM localization in brain, whereas GlialCAM is important for targeting MLC1 and ClC-2 to specialized glial domains in vivo and for modifying ClC-2’s biophysical properties specifically in oligodendrocytes (OLs), the cells chiefly affected by vacuolization. Unexpectedly, MLC1 is crucial for proper localization of GlialCAM and ClC-2, and for changing ClC-2 currents. Our data unmask an unforeseen functional relationship between MLC1 and ClC-2 in vivo, which is probably mediated by GlialCAM, and suggest that ClC-2 participates in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts.

Moclobemide exerts anti-inflammatory effect in lipopolysaccharide-activated primary mixed glial cell culture.

PubMed

Bielecka, A M; Paul-Samojedny, M; Obuchowicz, E

2010-12-01

An increasing body of evidence indicates that glial activation and neuroinflammation play an important role in the pathogenesis of psychiatric and neurodegenerative diseases. Activated glial cells secrete various cytokines that influence neurotransmission, hypothalamus-pituitary-adrenal axis activity, neuronal plasticity and neurogenesis. It has been suggested that alterations in cytokine networks are involved in the mechanism of action of antidepressant drugs. Until now, only a few studies demonstrated that some tricyclic antidepressants and selective serotonin reuptake inhibitors reduced production of pro-inflammatory cytokines in brain glia cells. We have investigated for the first time whether the antidepressant, moclobemide (a reversible selective inhibitor of monoamine oxidase-A) has an influence on pro-inflammatory cytokines [interleukin (IL)-1β and tumor necrosis factor (TNF)-α] and anti-inflammatory cytokine (IL-10) in primary rat mixed glial cell cultures stimulated by lipopolysaccharide (LPS). Our results showed that moclobemide used in a wide range of concentrations diminished LPS-stimulated IL-1β and TNF-α mRNAs expression in cellular extracts and remarkably reduced the levels of both pro-inflammatory cytokines in culture medium. In opposite to this, the drug had no influence on IL-10 mRNA and slightly reduced IL-10 concentration. Moreover, moclobemide decreased LPS-stimulated translocation of NFκB p65 subunit into cellular nuclei. These results suggest that moclobemide exerts anti-inflammatory effect in the central nervous system because it affects the balance between pro- and anti-inflammatory cytokines (IL-1β, TNF-α/IL-10) in primary mixed glial cell cultures.

P2 receptor signaling in neurons and glial cells of the central nervous system.

PubMed

Köles, Laszlo; Leichsenring, Anna; Rubini, Patrizia; Illes, Peter

2011-01-01

Purine and pyrimidine nucleotides are extracellular signaling molecules in the central nervous system (CNS) leaving the intracellular space of various CNS cell types via nonexocytotic mechanisms. In addition, ATP is a neuro-and gliotransmitter released by exocytosis from neurons and neuroglia. These nucleotides activate P2 receptors of the P2X (ligand-gated cationic channels) and P2Y (G protein-coupled receptors) types. In mammalians, seven P2X and eight P2Y receptor subunits occur; three P2X subtypes form homomeric or heteromeric P2X receptors. P2Y subtypes may also hetero-oligomerize with each other as well as with other G protein-coupled receptors. P2X receptors are able to physically associate with various types of ligand-gated ion channels and thereby to interact with them. The P2 receptor homomers or heteromers exhibit specific sensitivities against pharmacological ligands and have preferential functional roles. They may be situated at both presynaptic (nerve terminals) and postsynaptic (somatodendritic) sites of neurons, where they modulate either transmitter release or the postsynaptic sensitivity to neurotransmitters. P2 receptors exist at neuroglia (e.g., astrocytes, oligodendrocytes) and microglia in the CNS. The neuroglial P2 receptors subserve the neuron-glia cross talk especially via their end-feets projecting to neighboring synapses. In addition, glial networks are able to communicate through coordinated oscillations of their intracellular Ca(2+) over considerable distances. P2 receptors are involved in the physiological regulation of CNS functions as well as in its pathophysiological dysregulation. Normal (motivation, reward, embryonic and postnatal development, neuroregeneration) and abnormal regulatory mechanisms (pain, neuroinflammation, neurodegeneration, epilepsy) are important examples for the significance of P2 receptor-mediated/modulated processes. Copyright © 2011 Elsevier Inc. All rights reserved.

Absence of Ret Signaling in Mice Causes Progressive and Late Degeneration of the Nigrostriatal System

PubMed Central

Kramer, Edgar R; Aron, Liviu; Ramakers, Geert M. J; Seitz, Sabine; Zhuang, Xiaoxi; Beyer, Klaus; Smidt, Marten P; Klein, Rüdiger

2007-01-01

Support of ageing neurons by endogenous neurotrophic factors such as glial cell line–derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) may determine whether the neurons resist or succumb to neurodegeneration. GDNF has been tested in clinical trials for the treatment of Parkinson disease (PD), a common neurodegenerative disorder characterized by the loss of midbrain dopaminergic (DA) neurons. BDNF modulates nigrostriatal functions and rescues DA neurons in PD animal models. The physiological roles of GDNF and BDNF signaling in the adult nigrostriatal DA system are unknown. We generated mice with regionally selective ablations of the genes encoding the receptors for GDNF (Ret) and BDNF (TrkB). We find that Ret, but not TrkB, ablation causes progressive and adult-onset loss of DA neurons specifically in the substantia nigra pars compacta, degeneration of DA nerve terminals in striatum, and pronounced glial activation. These findings establish Ret as a critical regulator of long-term maintenance of the nigrostriatal DA system and suggest conditional Ret mutants as useful tools for gaining insights into the molecular mechanisms involved in the development of PD. PMID:17298183

What determines neurogenic competence in glia?

PubMed

Costa, Marcos Romualdo; Götz, Magdalena; Berninger, Benedikt

2010-05-01

One of the most intriguing discoveries during the last decade of developmental neurobiology is the fact that both in the developing and adult nervous system neural stem cells often turn out to have a glial identity: Radial glia generates neurons in the developing telencephalon of fish, birds and mammals and astro/radial glial stem cells in specialized neurogenic zones give rise to new neurons throughout life. What are the extrinsic signals acting on and the intrinsic signals acting within these glial populations endowing these with a neurogenic potential, whilst most other glia seemingly lack it? Studies on postnatal astroglia shed interesting light on this question as they are the intermediate between neurogenic radial glia and mature parenchymal astrocytes. At least in vitro their decision to acquire a glial fate is not yet irrevocable as forced expression of a single neurogenic transcription factor enables them to transgress their lineage and to give rise to fully functional neurons acquiring specific subtype characteristics. But even bona fide non-neurogenic glia in the adult nervous system can regain some of their radial glial heritage following injury as exemplified by reactive astroglia in the cerebral cortex and Müller glia in the retina. In this review first we will follow the direction of the physiological times' arrow, along which radial glia become transformed on one side into mature astrocytes gradually losing their neurogenic potential, while some of them seem to escape this dire destiny to settle in the few neurogenic oases of the adult brain where they generate neurons and glia throughout life. But we will also see how pathophysiological conditions partially can reverse the arrow of time reactivating the parenchymal astroglia to re-acquire some of the hallmarks of neural stem cells or progenitors. We will close this review with some thoughts on the surprising compatibility of the co-existence of a neural stem cell and glial identity within the very same cell from the perspective of the concept of transcriptional core networks. Copyright 2010 Elsevier B.V. All rights reserved.

Glial Cells in the Genesis and Regulation of Circadian Rhythms

PubMed Central

Chi-Castañeda, Donají; Ortega, Arturo

2018-01-01

Circadian rhythms are biological oscillations with a period of ~24 h. These rhythms are orchestrated by a circadian timekeeper in the suprachiasmatic nucleus of the hypothalamus, the circadian “master clock,” which exactly adjusts clock outputs to solar time via photic synchronization. At the molecular level, circadian rhythms are generated by the interaction of positive and negative feedback loops of transcriptional and translational processes of the so-called “clock genes.” A large number of clock genes encode numerous proteins that regulate their own transcription and that of other genes, collectively known as “clock-controlled genes.” In addition to the sleep/wake cycle, many cellular processes are regulated by circadian rhythms, including synaptic plasticity in which an exquisite interplay between neurons and glial cells takes place. In particular, there is compelling evidence suggesting that glial cells participate in and regulate synaptic plasticity in a circadian fashion, possibly representing the missing cellular and physiological link between circadian rhythms with learning and cognition processes. Here we review recent studies in support of this hypothesis, focusing on the interplay between glial cells, synaptic plasticity, and circadian rhythmogenesis. PMID:29483880

Developmental distribution of CaM kinase II in the antennal lobe of the sphinx moth Manduca sexta.

PubMed

Lohr, Christian; Bergstein, Sandra; Hirnet, Daniela

2007-01-01

The antennal lobe (primary olfactory center of insects) is completely reorganized during metamorphosis. This reorganization is accompanied by changing patterns of calcium signaling in neurons and glial cells. In the present study, we investigated the developmental distribution of a major calcium-dependent protein, viz., calcium/calmodulin-dependent protein kinase II (CaM kinase II), in the antennal lobe of the sphinx moth Manduca sexta by using a monoclonal antibody. During synaptogenesis (developmental stages 6-10), we found a redistribution of CaM kinase II immunoreactivity, from a homogeneous distribution in the immature neuropil to an accumulation in the neuropil of the glomeruli. CaM kinase II immunoreactivity was less intense in olfactory receptor axons of the antennal nerve and antennal lobe glial cells. Western blot analysis revealed a growing content of CaM kinase II in antennal lobe tissue throughout metamorphosis. Injection of the CaM kinase inhibitor KN-93 into pupae resulted in a reduced number of antennal lobe glial cells migrating into the neuropil to form borders around glomeruli. The results suggest that CaM kinase II is involved in glial cell migration.

Silencing the Kir4.1 potassium channel subunit in satellite glial cells of the rat trigeminal ganglion results in pain-like behavior in the absence of nerve injury.

PubMed

Vit, Jean-Philippe; Ohara, Peter T; Bhargava, Aditi; Kelley, Kanwar; Jasmin, Luc

2008-04-16

Growing evidence suggests that changes in the ion buffering capacity of glial cells can give rise to neuropathic pain. In the CNS, potassium ion (K+) buffering is dependent on the glia-specific inward rectifying K+ channel Kir4.1. We recently reported that the satellite glial cells that surround primary sensory neurons located in sensory ganglia of the peripheral nervous system also express Kir4.1, whereas the neurons do not. In the present study, we show that, in the rat trigeminal ganglion, the location of the primary sensory neurons for face sensation, specific silencing of Kir4.1 using RNA interference leads to spontaneous and evoked facial pain-like behavior in freely moving rats. We also show that Kir4.1 in the trigeminal ganglion is reduced after chronic constriction injury of the infraorbital nerve. These findings suggests that neuropathic pain can result from a change in expression of a single K+ channel in peripheral glial cells, raising the possibility of targeting Kir4.1 to treat pain in general and particularly neuropathic pain that occurs in the absence of nerve injury.

Silencing the Kir4.1 potassium channel subunit in satellite glial cells of the rat trigeminal ganglion results in pain-like behavior in the absence of nerve injury

PubMed Central

Vit, Jean-Philippe; Ohara, Peter T.; Bhargava, Aditi; Kelley, Kanwar; Jasmin, Luc

2008-01-01

Growing evidence suggests that changes in the ion buffering capacity of glial cells can give rise to neuropathic pain. In the CNS, potassium ion (K+) buffering is dependent on the glia-specific inward rectifying K+ channel Kir4.1. We recently reported that the satellite glial cells (SGCs) that surround primary sensory neurons located in sensory ganglia of the peripheral nervous system also express Kir4.1 while the neurons do not. In the present study we show that in the rat trigeminal ganglion, the location of the primary sensory neurons for face sensation, specific silencing of Kir4.1 using RNA interference leads to spontaneous and evoked facial pain-like behavior in freely moving rats. We also show that Kir4.1 in the trigeminal ganglion is reduced following chronic constriction injury of the infraorbital nerve. These findings suggests that neuropathic pain can result from a change in expression of a single K+ channel in peripheral glial cells, raising the possibility of targeting Kir4.1 to treat pain in general, and particularly neuropathic pain that occurs in the absence of nerve injury. PMID:18417695

Neuroinflammation and physical exercise as modulators of adult hippocampal neural precursor cell behavior.

PubMed

Pérez-Domínguez, Martha; Tovar-Y-Romo, Luis B; Zepeda, Angélica

2018-01-26

The dentate gyrus of the hippocampus is a plastic structure where adult neurogenesis constitutively occurs. Cell components of the neurogenic niche are source of paracrine as well as membrane-bound factors such as Notch, Bone Morphogenetic Proteins, Wnts, Sonic Hedgehog, cytokines, and growth factors that regulate adult hippocampal neurogenesis and cell fate decision. The integration and coordinated action of multiple extrinsic and intrinsic cues drive a continuous decision process: if adult neural stem cells remain quiescent or proliferate, if they take a neuronal or a glial lineage, and if new cells proliferate, undergo apoptotic death, or survive. The proper balance in the molecular milieu of this neurogenic niche leads to the production of neurons in a higher rate as that of astrocytes. But this rate changes in face of microenvironment modifications as those driven by physical exercise or with neuroinflammation. In this work, we first review the cellular and molecular components of the subgranular zone, focusing on the molecules, active signaling pathways and genetic programs that maintain quiescence, induce proliferation, or promote differentiation. We then summarize the evidence regarding the role of neuroinflammation and physical exercise in the modulation of adult hippocampal neurogenesis with emphasis on the activation of progression from adult neural stem cells to lineage-committed progenitors to their progeny mainly in murine models.

ER stress and genomic instability induced by gamma radiation in mice primary cultured glial cells.

PubMed

Chatterjee, Jit; Nairy, Rajesha K; Langhnoja, Jaldeep; Tripathi, Ashutosh; Patil, Rajashekhar K; Pillai, Prakash P; Mustak, Mohammed S

2018-06-01

Ionizing radiation induces various pathophysiological conditions by altering central nervous system (CNS) homeostasis, leading to neurodegenerative diseases. However, the potential effect of ionizing radiation response on cellular physiology in glial cells is unclear. In the present study, micronucleus test, comet assay, and RT-PCR were performed to investigate the potential effect of gamma radiation in cultured oligodendrocytes and astrocytes with respect to genomic instability, Endoplasmic Reticulum (ER) stress, and inflammation. Further, we studied the effect of alteration in ER stress specific gene expression in cortex post whole body radiation in mice. Results showed that exposure of gamma radiation of 2Gy in-vitro cultured astrocytes and oligodendrocytes and 7Gy in-vivo induced ER stress and Inflammation along with profuse DNA damage and Chromosomal abnormality. Additionally, we observed downregulation of myelin basic protein levels in cultured oligodendrocytes exposed to radiation. The present data suggests that ER stress and pro inflammatory cytokines serve as the major players in inducing glial cell dysfunction post gamma irradiation along with induction of genomic instability. Taken together, these results indicate that ER stress, DNA damage, and inflammatory pathways may be critical events leading to glial cell dysfunction and subsequent cell death following exposure to ionizing radiation.

Differential Acute and Chronic Effects of Leptin on Hypothalamic Astrocyte Morphology and Synaptic Protein Levels

PubMed Central

García-Cáceres, Cristina; Fuente-Martín, Esther; Burgos-Ramos, Emma; Granado, Miriam; Frago, Laura M.; Barrios, Vicente; Horvath, Tamas

2011-01-01

Astrocytes participate in neuroendocrine functions partially through modulation of synaptic input density in the hypothalamus. Indeed, glial ensheathing of neurons is modified by specific hormones, thus determining the availability of neuronal membrane space for synaptic inputs, with the loss of this plasticity possibly being involved in pathological processes. Leptin modulates synaptic inputs in the hypothalamus, but whether astrocytes participate in this action is unknown. Here we report that astrocyte structural proteins, such as glial fibrillary acidic protein (GFAP) and vimentin, are induced and astrocyte morphology modified by chronic leptin administration (intracerebroventricular, 2 wk), with these changes being inversely related to modifications in synaptic protein densities. Similar changes in glial structural proteins were observed in adult male rats that had increased body weight and circulating leptin levels due to neonatal overnutrition (overnutrition: four pups/litter vs. control: 12 pups/litter). However, acute leptin treatment reduced hypothalamic GFAP levels and induced synaptic protein levels 1 h after administration, with no effect on vimentin. In primary hypothalamic astrocyte cultures leptin also reduced GFAP levels at 1 h, with an induction at 24 h, indicating a possible direct effect of leptin. Hence, one mechanism by which leptin may affect metabolism is by modifying hypothalamic astrocyte morphology, which in turn could alter synaptic inputs to hypothalamic neurons. Furthermore, the responses to acute and chronic leptin exposure are inverse, raising the possibility that increased glial activation in response to chronic leptin exposure could be involved in central leptin resistance. PMID:21343257

Phasor Fluorescence Lifetime Microscopy of Free and Protein-Bound NADH Reveals Neural Stem Cell Differentiation Potential

PubMed Central

Stringari, Chiara; Nourse, Jamison L.; Flanagan, Lisa A.; Gratton, Enrico

2012-01-01

In the stem cell field there is a lack of non invasive and fast methods to identify stem cell’s metabolic state, differentiation state and cell-lineage commitment. Here we describe a label-free method that uses NADH as an intrinsic biomarker and the Phasor approach to Fluorescence Lifetime microscopy to measure the metabolic fingerprint of cells. We show that different metabolic states are related to different cell differentiation stages and to stem cell bias to neuronal and glial fate, prior the expression of lineage markers. Our data demonstrate that the NADH FLIM signature distinguishes non-invasively neurons from undifferentiated neural progenitor and stem cells (NPSCs) at two different developmental stages (E12 and E16). NPSCs follow a metabolic trajectory from a glycolytic phenotype to an oxidative phosphorylation phenotype through different stages of differentiation. NSPCs are characterized by high free/bound NADH ratio, while differentiated neurons are characterized by low free/bound NADH ratio. We demonstrate that the metabolic signature of NPSCs correlates with their differentiation potential, showing that neuronal progenitors and glial progenitors have a different free/bound NADH ratio. Reducing conditions in NPSCs correlates with their neurogenic potential, while oxidative conditions correlate with glial potential. For the first time we show that FLIM NADH metabolic fingerprint provides a novel, and quantitative measure of stem cell potential and a label-free and non-invasive means to identify neuron- or glial- biased progenitors. PMID:23144844

Enteric glia.

PubMed

Rühl, A; Nasser, Y; Sharkey, K A

2004-04-01

The enteric nervous system is composed of both enteric neurones and enteric glia. Enteric glial cells were first described by Dogiel and are now known to outnumber neurones approximately 4 : 1. In the past, these cells were assumed to subserve a largely supportive role; however, recent evidence indicates that enteric glial cells may play a more active role in the control of gut function. In transgenic mouse models, where enteric glial cells are selectively ablated, the loss of glia results in intestinal inflammation and disruption of the epithelial barrier. Enteric glia are activated specifically by inflammatory insults and may contribute actively to inflammatory pathology via antigen presentation and cytokine synthesis. Enteric glia also express receptors for neurotransmitters and so may serve as intermediaries in enteric neurotransmission. Thus, enteric glia may serve as a link between the nervous and immune systems of the gut and may also have an important role in maintaining the integrity of the mucosal barrier and in other aspects of intestinal homeostasis.

ER stress upregulated PGE2/IFNγ-induced IL-6 expression and down-regulated iNOS expression in glial cells

NASA Astrophysics Data System (ADS)

Hosoi, Toru; Honda, Miya; Oba, Tatsuya; Ozawa, Koichiro

2013-12-01

The disruption of endoplasmic reticulum (ER) function can lead to neurodegenerative disorders, in which inflammation has also been implicated. We investigated the possible correlation between ER stress and immune function using glial cells. We demonstrated that ER stress synergistically enhanced prostaglandin (PG) E2 + interferon (IFN) γ-induced interleukin (IL)-6 production. This effect was mediated through cAMP. Immune-activated glial cells produced inducible nitric oxide synthase (iNOS). Interestingly, ER stress inhibited PGE2 + IFNγ-induced iNOS expression. Similar results were obtained when cells were treated with dbcAMP + IFNγ. Thus, cAMP has a dual effect on immune reactions; cAMP up-regulated IL-6 expression, but down-regulated iNOS expression under ER stress. Therefore, our results suggest a link between ER stress and immune reactions in neurodegenerative diseases.

MICEST: a Potential Tool for Non-invasive Detection of Molecular Changes in Alzheimer’s Disease

PubMed Central

Haris, Mohammad; Singh, Anup; Cai, Kejia; Nath, Kavindra; Crescenzi, Rachelle; Kogan, Feliks; Hariharan, Hari; Reddy, Ravinder

2012-01-01

Myo-Inositol (mIns) is a marker of glial cells proliferation and has been shown to increase in early Alzheimer’s disease (AD) pathology. mIns exhibits a concentration dependent chemical-exchange-saturation-transfer (CEST) effect (MICEST) between its hydroxyl groups and bulk water protons. Using the endogenous MICEST technique brain mIns concentration and glial cells proliferation can be mapped at high spatial resolution. The high resolution mapping of mIns was performed using MICEST technique on ~20 months old APP-PS1 transgenic mouse model of AD as well as on age matched wild type (WT) control (n=5). The APP-PS1 mice show ~50% higher MICEST contrast than WT control with concomitant increase in mIns concentration as measured through proton spectroscopy. Immunostaining against glial-fibric-acidic protein also depicts proliferative glial cells in larger extent in APP-PS1 than WT mice, which correspond to the higher mIns concentration. Potential significance of MICEST in early detection of AD pathology is discussed in detail. PMID:23041110

Nicotine Uses Neuron-Glia Communication to Enhance Hippocampal Synaptic Transmission and Long-term Memory

PubMed Central

López-Hidalgo, Mónica; Salgado-Puga, Karla; Alvarado-Martínez, Reynaldo; Medina, Andrea Cristina; Prado-Alcalá, Roberto A.; García-Colunga, Jesús

2012-01-01

Nicotine enhances synaptic transmission and facilitates long-term memory. Now it is known that bi-directional glia-neuron interactions play important roles in the physiology of the brain. However, the involvement of glial cells in the effects of nicotine has not been considered until now. In particular, the gliotransmitter D-serine, an endogenous co-agonist of NMDA receptors, enables different types of synaptic plasticity and memory in the hippocampus. Here, we report that hippocampal long-term synaptic plasticity induced by nicotine was annulled by an enzyme that degrades endogenous D-serine, or by an NMDA receptor antagonist that acts at the D-serine binding site. Accordingly, both effects of nicotine: the enhancement of synaptic transmission and facilitation of long-term memory were eliminated by impairing glial cells with fluoroacetate, and were restored with exogenous D-serine. Together, these results show that glial D-serine is essential for the long-term effects of nicotine on synaptic plasticity and memory, and they highlight the roles of glial cells as key participants in brain functions. PMID:23185511

Characterization of multiciliated ependymal cells that emerge in the neurogenic niche of the aged zebrafish brain.

PubMed

Ogino, Takashi; Sawada, Masato; Takase, Hiroshi; Nakai, Chiemi; Herranz-Pérez, Vicente; Cebrián-Silla, Arantxa; Kaneko, Naoko; García-Verdugo, José Manuel; Sawamoto, Kazunobu

2016-10-15

In mammals, ventricular walls of the developing brain maintain a neurogenic niche, in which radial glial cells act as neural stem cells (NSCs) and generate new neurons in the embryo. In the adult brain, the neurogenic niche is maintained in the ventricular-subventricular zone (V-SVZ) of the lateral wall of lateral ventricles and the hippocampal dentate gyrus. In the neonatal V-SVZ, radial glial cells transform into astrocytic postnatal NSCs and multiciliated ependymal cells. On the other hand, in zebrafish, radial glial cells continue to cover the surface of the adult telencephalic ventricle and maintain a higher neurogenic potential in the adult brain. However, the cell composition of the neurogenic niche of the aged zebrafish brain has not been investigated. Here we show that multiciliated ependymal cells emerge in the neurogenic niche of the aged zebrafish telencephalon. These multiciliated cells appear predominantly in the dorsal part of the ventral telencephalic ventricular zone, which also contains clusters of migrating new neurons. Scanning electron microscopy and live imaging analyses indicated that these multiple cilia beat coordinately and generate constant fluid flow within the ventral telencephalic ventricle. Analysis of the cell composition by transmission electron microscopy revealed that the neurogenic niche in the aged zebrafish contains different types of cells, with ultrastructures similar to those of ependymal cells, transit-amplifying cells, and migrating new neurons in postnatal mice. These data suggest that the transformation capacity of radial glial cells is conserved but that its timing is different between fish and mice. J. Comp. Neurol. 524:2982-2992, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Holographic Photolysis for Multiple Cell Stimulation in Mouse Hippocampal Slices

PubMed Central

Papagiakoumou, Eirini; Ventalon, Cathie; Angulo, María Cecilia; Emiliani, Valentina

2010-01-01

Background Advanced light microscopy offers sensitive and non-invasive means to image neural activity and to control signaling with photolysable molecules and, recently, light-gated channels. These approaches require precise and yet flexible light excitation patterns. For synchronous stimulation of subsets of cells, they also require large excitation areas with millisecond and micrometric resolution. We have recently developed a new method for such optical control using a phase holographic modulation of optical wave-fronts, which minimizes power loss, enables rapid switching between excitation patterns, and allows a true 3D sculpting of the excitation volumes. In previous studies we have used holographic photololysis to control glutamate uncaging on single neuronal cells. Here, we extend the use of holographic photolysis for the excitation of multiple neurons and of glial cells. Methods/Principal Findings The system combines a liquid crystal device for holographic patterned photostimulation, high-resolution optical imaging, the HiLo microscopy, to define the stimulated regions and a conventional Ca2+ imaging system to detect neural activity. By means of electrophysiological recordings and calcium imaging in acute hippocampal slices, we show that the use of excitation patterns precisely tailored to the shape of multiple neuronal somata represents a very efficient way for the simultaneous excitation of a group of neurons. In addition, we demonstrate that fast shaped illumination patterns also induce reliable responses in single glial cells. Conclusions/Significance We show that the main advantage of holographic illumination is that it allows for an efficient excitation of multiple cells with a spatiotemporal resolution unachievable with other existing approaches. Although this paper focuses on the photoactivation of caged molecules, our approach will surely prove very efficient for other probes, such as light-gated channels, genetically encoded photoactivatable proteins, photoactivatable fluorescent proteins, and voltage-sensitive dyes. PMID:20195547

Elevated Myo-Inositol, Choline, and Glutamate Levels in the Associative Striatum of Antipsychotic-Naive Patients With First-Episode Psychosis: A Proton Magnetic Resonance Spectroscopy Study With Implications for Glial Dysfunction

PubMed Central

Plitman, Eric; de la Fuente-Sandoval, Camilo; Reyes-Madrigal, Francisco; Chavez, Sofia; Gómez-Cruz, Gladys; León-Ortiz, Pablo; Graff-Guerrero, Ariel

2016-01-01

Glial disturbances are highly implicated in the pathophysiology of schizophrenia and may be linked with glutamatergic dysregulation. Myo-inositol (mI), a putative marker of glial cells, and choline (Cho), representative of membrane turnover, are both present in larger concentrations within glial cells than in neurons, and their elevation is often interpreted to reflect glial activation. Proton magnetic resonance spectroscopy (1H-MRS) allows for the evaluation of mI, Cho, glutamate, glutamate + glutamine (Glx), and N-acetylaspartate (NAA). A collective investigation of these measures in antipsychotic-naive patients experiencing their first nonaffective episode of psychosis (FEP) can improve the understanding of glial dysfunction and its implications in the early stages of schizophrenia. 3-Tesla 1H-MRS (echo time = 35ms) was performed in 60 antipsychotic-naive patients with FEP and 60 age- and sex-matched healthy controls. mI, Cho, glutamate, Glx, and NAA were estimated using LCModel and corrected for cerebrospinal fluid composition within the voxel. mI, Cho, and glutamate were elevated in the FEP group. After correction for multiple comparisons, mI positively correlated with grandiosity. The relationships between mI and glutamate, and Cho and glutamate, were more positive in the FEP group. These findings are suggestive of glial activation in the absence of neuronal loss and may thereby provide support for the presence of a neuroinflammatory process within the early stages of schizophrenia. Dysregulation of glial function might result in the disruption of glutamatergic neurotransmission, which may influence positive symptomatology in patients with FEP. PMID:26320195

Elevated Myo-Inositol, Choline, and Glutamate Levels in the Associative Striatum of Antipsychotic-Naive Patients With First-Episode Psychosis: A Proton Magnetic Resonance Spectroscopy Study With Implications for Glial Dysfunction.

PubMed

Plitman, Eric; de la Fuente-Sandoval, Camilo; Reyes-Madrigal, Francisco; Chavez, Sofia; Gómez-Cruz, Gladys; León-Ortiz, Pablo; Graff-Guerrero, Ariel

2016-03-01

Glial disturbances are highly implicated in the pathophysiology of schizophrenia and may be linked with glutamatergic dysregulation. Myo-inositol (mI), a putative marker of glial cells, and choline (Cho), representative of membrane turnover, are both present in larger concentrations within glial cells than in neurons, and their elevation is often interpreted to reflect glial activation. Proton magnetic resonance spectroscopy ((1)H-MRS) allows for the evaluation of mI, Cho, glutamate, glutamate + glutamine (Glx), and N-acetylaspartate (NAA). A collective investigation of these measures in antipsychotic-naive patients experiencing their first nonaffective episode of psychosis (FEP) can improve the understanding of glial dysfunction and its implications in the early stages of schizophrenia. 3-Tesla (1)H-MRS (echo time = 35 ms) was performed in 60 antipsychotic-naive patients with FEP and 60 age- and sex-matched healthy controls. mI, Cho, glutamate, Glx, and NAA were estimated using LCModel and corrected for cerebrospinal fluid composition within the voxel. mI, Cho, and glutamate were elevated in the FEP group. After correction for multiple comparisons, mI positively correlated with grandiosity. The relationships between mI and glutamate, and Cho and glutamate, were more positive in the FEP group. These findings are suggestive of glial activation in the absence of neuronal loss and may thereby provide support for the presence of a neuroinflammatory process within the early stages of schizophrenia. Dysregulation of glial function might result in the disruption of glutamatergic neurotransmission, which may influence positive symptomatology in patients with FEP. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Gliosarcomas arising from the pineal gland region: uncommon localization and rare tumors.

PubMed

Sugita, Yasuo; Terasaki, Mizuhiko; Tanigawa, Ken; Ohshima, Koichi; Morioka, Motohiro; Higaki, Koichi; Nakagawa, Setsuko; Shimokawa, Shoko; Nakashima, Susumu

2016-02-01

Gliosarcomas are a variant of glioblastomas and present a biphasic pattern, with coexisting glial and mesenchymal components. In this study, two unusual cases are presented. Case 1 is a 52-year-old woman with a headache and memory disturbance for a month. Case 2 is an 18-year-old man with a headache lasting two weeks. In both cases, an MRI revealed enhancing T1-low to iso, T2-iso to high intensity lesions in the pineal gland region. Histologically, in case 1, the tumor showed spindle cell proliferation with disorganized fascicles and cellular pleomorphism. Tumor cells variously exhibited oncocytic transformation. Immunohistochemically, most of the spindle tumor cells were positive for myoglobin and desmin. Some of the tumor cells were positive for GFAP and S-100 protein. On the other hand, all tumor cells were positive for CD133, Musashi1, and SOX-2 which are the markers of neural stem cells. In case 2, the tumor showed monotonous proliferation of short spindle cells with disorganized fascicles and cellular atypism. The morphological distinction between glial and mesenchymal components was not apparent. Immunohistochemically, most of the spindle tumor cells were positive for desmin. Glial tumor cells that were dispersed within the sarcoma as single cells were positive for GFAP. In addition, all tumor cells were positive for CD133, Musashi1 and SOX-2. Based on these microscopic appearances, and immunohistochemical findings, these cases were diagnosed as gliosarcomas arising from the pineal gland region. These results also indicated that pluripotential cancer stem cells differentiated into glial and muscle cell lines at the time of tumor growth. In a survey of previous publications on gliosarcoma arising from the pineal gland, these cases are the second and third reports found in English scientific writings. © 2015 Japanese Society of Neuropathology.

Establishment of a long-term spiral ganglion neuron culture with reduced glial cell number: Effects of AraC on cell composition and neurons.

PubMed

Schwieger, Jana; Esser, Karl-Heinz; Lenarz, Thomas; Scheper, Verena

2016-08-01

Sensorineural deafness is mainly caused by damage to hair cells and degeneration of the spiral ganglion neurons (SGN). Cochlear implants can functionally replace lost hair cells and stimulate the SGN electrically. The benefit from cochlear implantation depends on the number and excitability of these neurons. To identify potential therapies for SGN protection, in vitro tests are carried out on spiral ganglion cells (SGC). A glial cell-reduced and neuron-enhanced culture of neonatal rat SGC under mitotic inhibition (cytarabine (AraC)) for up to seven days is presented. Serum containing and neurotrophin-enriched cultures with and without AraC-addition were analyzed after 4 and 7 days. The total number of cells was significantly reduced, while the proportion of neurons was greatly increased by AraC-treatment. Cell type-specific labeling demonstrated that nearly all fibroblasts and most of the glial cells were removed. Neither the neuronal survival, nor the neurite outgrowth or soma diameter were negatively affected. Additionally neurites remain partly free of surrounding non-neuronal cells. Recent culture conditions allow only for short-term cultivation of neonatal SGC and lack information on the influence of non-neuronal cells on SGN and of direct contact of neurites with test-materials. AraC-addition reduces the number of non-neuronal cells and increases the ratio of SGN in culture, without negative impact on neuronal viability. This treatment allows longer-term cultivation of SGC and provides deeper insight into SGN-glial cell interaction and the attachment of neurites on test-material surfaces. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Setting the Stage for Personalized Treatment of Glioma | Center for Cancer Research

Cancer.gov

Gliomas, the most common type of primary brain tumors in adults, arise from different types of glial cells, which support and protect the neurons of the central nervous system. How a patient’s glioma is treated depends in part on the type of glial cell from which the tumor developed. Classification of gliomas has traditionally been done by microscopic analysis of tumor

Truncated tyrosine kinase B brain-derived neurotrophic factor receptor directs cortical neural stem cells to a glial cell fate by a novel signaling mechanism.

PubMed

Cheng, Aiwu; Coksaygan, Turhan; Tang, Hongyan; Khatri, Rina; Balice-Gordon, Rita J; Rao, Mahendra S; Mattson, Mark P

2007-03-01

During development of the mammalian cerebral cortex neural stem cells (NSC) first generate neurons and subsequently produce glial cells. The mechanism(s) responsible for this developmental shift from neurogenesis to gliogenesis is unknown. Brain-derived neurotrophic factor (BDNF) is believed to play important roles in the development of the mammalian cerebral cortex; it enhances neurogenesis and promotes the differentiation and survival of newly generated neurons. Here, we provide evidence that a truncated form of the BDNF receptor tyrosine kinase B (trkB-t) plays a pivotal role in directing embryonic mouse cortical NSC to a glial cell fate. Expression of trkB-t promotes differentiation of NSC toward astrocytes while inhibiting neurogenesis both in cell culture and in vivo. The mechanism by which trkB-t induces astrocyte genesis is not simply the result of inhibition of full-length receptor with intrinsic tyrosine kinase activity signaling. Instead, binding of BDNF to trkB-t activates a signaling pathway (involving a G-protein and protein kinase C) that induced NSC to become glial progenitors and astrocytes. Thus, the increased expression of trkB-t in the embryonic cerebral cortex that occurs coincident with astrocyte production plays a pivotal role in the developmental transition from neurogenesis to gliogenesis. Our findings suggest a mechanism by which a single factor (BDNF) regulates the production of the two major cell types in the mammalian cerebral cortex.

Invaginating Structures in Mammalian Synapses

PubMed Central

Petralia, Ronald S.; Wang, Ya-Xian; Mattson, Mark P.; Yao, Pamela J.

2018-01-01

Invaginating structures at chemical synapses in the mammalian nervous system exist in presynaptic axon terminals, postsynaptic spines or dendrites, and glial processes. These invaginating structures can be divided into three categories. The first category includes slender protrusions invaginating into axonal terminals, postsynaptic spines, or glial processes. Best known examples of this category are spinules extending from postsynaptic spines into presynaptic terminals in forebrain synapses. Another example of this category are protrusions from inhibitory presynaptic terminals invaginating into postsynaptic neuronal somas. Regardless of the direction and location, the invaginating structures of the first category do not have synaptic active zones within the invagination. The second category includes postsynaptic spines invaginating into presynaptic terminals, whereas the third category includes presynaptic terminals invaginating into postsynaptic spines or dendrites. Unlike the first category, the second and third categories have active zones within the invagination. An example of the second category are mossy terminal synapses of the hippocampal CA3 region, in which enlarged spine-like structures invaginate partly or entirely into mossy terminals. An example of the third category is the neuromuscular junction (NMJ) where substantial invaginations of the presynaptic terminals invaginate into the muscle fibers. In the retina, rod and cone synapses have invaginating processes from horizontal and bipolar cells. Because horizontal cells act both as post and presynaptic structures, their invaginating processes represent both the second and third category. These invaginating structures likely play broad yet specialized roles in modulating neuronal cell signaling. PMID:29674962

Uncovering Novel Roles of Nonneuronal Cells in Body Weight Homeostasis and Obesity

PubMed Central

Argente, Jesús

2013-01-01

Glial cells, which constitute more than 50% of the mass of the central nervous system and greatly outnumber neurons, are at the vanguard of neuroendocrine research in metabolic control and obesity. Historically relegated to roles of structural support and protection, diverse functions have been gradually attributed to this heterogeneous class of cells with their protagonism in crescendo in all areas of neuroscience during the past decade. However, this dramatic increase in attention bestowed upon glial cells has also emphasized our vast lack of knowledge concerning many aspects of their physiological functions, let alone their participation in numerous pathologies. This minireview focuses on the recent advances in our understanding of how glial cells participate in the physiological regulation of appetite and systemic metabolism as well as their role in the pathophysiological response to poor nutrition and secondary complications associated with obesity. Moreover, we highlight some of the existing lagoons of knowledge in this increasingly important area of investigation. PMID:23798599

The Role of Glia in Sleep Regulation and Function.

PubMed

Frank, Marcos G

2018-01-28

The cellular mechanisms governing the expression, regulation, and function of sleep are not entirely understood. The traditional view is that these mechanisms are neuronal. An alternative view is that glial brain cells may play important roles in these processes. Their ubiquity in the central nervous system makes them well positioned to modulate neuronal circuits that gate sleep and wake. Their ability to respond to chemical neuronal signals suggests that they form feedback loops with neurons that may globally regulate neuronal activity. Their potential role in detoxifying the brain, regulating neuronal metabolism, and promoting synaptic plasticity raises the intriguing possibility that glia mediate important functions ascribed to sleep.

Non-Neuronal Cells Are Required to Mediate the Effects of Neuroinflammation: Results from a Neuron-Enriched Culture System.

PubMed

Hui, Chin Wai; Zhang, Yang; Herrup, Karl

2016-01-01

Chronic inflammation is associated with activated microglia and reactive astrocytes and plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer's. Both in vivo and in vitro studies have demonstrated that inflammatory cytokine responses to immune challenges contribute to neuronal death during neurodegeneration. In order to investigate the role of glial cells in this phenomenon, we developed a modified method to remove the non-neuronal cells in primary cultures of E16.5 mouse cortex. We modified previously reported methods as we found that a brief treatment with the thymidine analog, 5-fluorodeoxyuridine (FdU), is sufficient to substantially deplete dividing non-neuronal cells in primary cultures. Cell cycle and glial markers confirm the loss of ~99% of all microglia, astrocytes and oligodendrocyte precursor cells (OPCs). More importantly, under this milder treatment, the neurons suffered neither cell loss nor any morphological defects up to 2.5 weeks later; both pre- and post-synaptic markers were retained. Further, neurons in FdU-treated cultures remained responsive to excitotoxicity induced by glutamate application. The immunobiology of the FdU culture, however, was significantly changed. Compared with mixed culture, the protein levels of NFκB p65 and the gene expression of several cytokine receptors were altered. Individual cytokines or conditioned medium from β-amyloid-stimulated THP-1 cells that were, potent neurotoxins in normal, mixed cultures, were virtually inactive in the absence of glial cells. The results highlight the importance of our glial-depleted culture system and identifies and offer unexpected insights into the complexity of -brain neuroinflammation.

Reduction in the number of astrocytes and their projections is associated with increased synaptic protein density in the hypothalamus of poorly controlled diabetic rats.

PubMed

Lechuga-Sancho, Alfonso M; Arroba, Ana I; Frago, Laura M; García-Cáceres, Cristina; de Célix, Arancha Delgado-Rubín; Argente, Jesús; Chowen, Julie A

2006-11-01

Processes under hypothalamic control, such as thermogenesis, feeding behavior, and pituitary hormone secretion, are disrupted in poorly controlled diabetes, but the underlying mechanisms are poorly understood. Because glial cells regulate neurosecretory neurons through modulation of synaptic inputs and function, we investigated the changes in hypothalamic glia in rats with streptozotocin-induced diabetes mellitus. Hypothalamic glial fibrillary acidic protein (GFAP) levels decreased significantly 6 wk after diabetes onset. This was coincident with decreased GFAP immunoreactive surface area, astrocyte number, and the extension of GFAP immunoreactive processes/astrocyte in the arcuate nucleus. Cell death, analyzed by terminal deoxyuridine 5-triphosphate nick-end labeling and ELISA, increased significantly at 4 wk of diabetes. Proliferation, measured by Western blot for proliferating cell nuclear antigen and immunostaining for phosphorylated histone H-3, decreased in the hypothalamus of diabetic rats throughout the study, becoming significantly reduced by 8 wk. Both proliferation and death affected astroctyes because both phosphorylated histone H-3- and terminal deoxyuridine 5-triphosphate nick-end labeling-labeled cells were GFAP positive. Western blot analysis revealed that postsynaptic density protein 95 and the presynaptic proteins synapsin I and synaptotagmin increased significantly at 8 wk of diabetes, suggesting increased hypothalamic synaptic density. Thus, in poorly controlled diabetic rats, there is a decrease in the number of hypothalamic astrocytes that is correlated with modifications in synaptic proteins and possibly synaptic inputs. These morphological changes in the arcuate nucleus could be involved in neurosecretory and metabolic changes seen in diabetic animals.

Bidirectional brain-gut interactions and chronic pathological changes after traumatic brain injury in mice.

PubMed

Ma, Elise L; Smith, Allen D; Desai, Neemesh; Cheung, Lumei; Hanscom, Marie; Stoica, Bogdan A; Loane, David J; Shea-Donohue, Terez; Faden, Alan I

2017-11-01

Traumatic brain injury (TBI) has complex effects on the gastrointestinal tract that are associated with TBI-related morbidity and mortality. We examined changes in mucosal barrier properties and enteric glial cell response in the gut after experimental TBI in mice, as well as effects of the enteric pathogen Citrobacter rodentium (Cr) on both gut and brain after injury. Moderate-level TBI was induced in C57BL/6mice by controlled cortical impact (CCI). Mucosal barrier function was assessed by transepithelial resistance, fluorescent-labelled dextran flux, and quantification of tight junction proteins. Enteric glial cell number and activation were measured by Sox10 expression and GFAP reactivity, respectively. Separate groups of mice were challenged with Cr infection during the chronic phase of TBI, and host immune response, barrier integrity, enteric glial cell reactivity, and progression of brain injury and inflammation were assessed. Chronic CCI induced changes in colon morphology, including increased mucosal depth and smooth muscle thickening. At day 28 post-CCI, increased paracellular permeability and decreased claudin-1 mRNA and protein expression were observed in the absence of inflammation in the colon. Colonic glial cell GFAP and Sox10 expression were significantly increased 28days after brain injury. Clearance of Cr and upregulation of Th1/Th17 cytokines in the colon were unaffected by CCI; however, colonic paracellular flux and enteric glial cell GFAP expression were significantly increased. Importantly, Cr infection in chronically-injured mice worsened the brain lesion injury and increased astrocyte- and microglial-mediated inflammation. These experimental studies demonstrate chronic and bidirectional brain-gut interactions after TBI, which may negatively impact late outcomes after brain injury. Copyright © 2017 Elsevier Inc. All rights reserved.

Patch-clamp, ion-sensing, and glutamate-sensing techniques to study glutamate transport in isolated retinal glial cells.

PubMed

Billups, B; Szatkowski, M; Rossi, D; Attwell, D

1998-01-01

We have described how a combination of electrical, ion-sensing, and glutamate-sensing techniques has advanced our understanding of glutamate uptake into isolated salamander retinal glial cells. The next steps in understanding glutamate transport will inevitably depend strongly on molecular biological methods, as described elsewhere in this book, but will also require more detailed study of transporters in their normal environment, perhaps by using patch-clamping or imaging techniques to study cells in situ.

Regulation of neuronal axon specification by glia-neuron gap junctions in C. elegans.

PubMed

Meng, Lingfeng; Zhang, Albert; Jin, Yishi; Yan, Dong

2016-10-21

Axon specification is a critical step in neuronal development, and the function of glial cells in this process is not fully understood. Here, we show that C. elegans GLR glial cells regulate axon specification of their nearby GABAergic RME neurons through GLR-RME gap junctions. Disruption of GLR-RME gap junctions causes misaccumulation of axonal markers in non-axonal neurites of RME neurons and converts microtubules in those neurites to form an axon-like assembly. We further uncover that GLR-RME gap junctions regulate RME axon specification through activation of the CDK-5 pathway in a calcium-dependent manner, involving a calpain clp-4 . Therefore, our study reveals the function of glia-neuron gap junctions in neuronal axon specification and shows that calcium originated from glial cells can regulate neuronal intracellular pathways through gap junctions.

Cellular complexity in subcortical white matter: a distributed control circuit?

PubMed

Colombo, Jorge A

2018-03-01

The subcortical white matter (SWM) has been traditionally considered as a site for passive-neutral-information transfer through cerebral cortex association and projection fibers. Yet, the presence of subcortical neuronal and glial "interstitial" cells expressing immunolabelled neurotransmitters/neuromodulators and synaptic vesicular proteins, and recent immunohistochemical and electrophysiological observations on the rat visual cortex as well as interactive regulation of myelinating processes support the possibility that SWM nests subcortical, regionally variable, distributed neuronal-glial circuits, that could influence information transfer. Their hypothetical involvement in regulating the timing and signal transfer probability at the SWM axonal components ought to be considered and experimentally analysed. Thus, the "interstitial" neuronal cells-associated with local glial cells-traditionally considered to be vestigial and functionally inert under normal conditions, they may well turn to be critical in regulating information transfer at the SWM.

Schwann Cell Phenotype Changes in Aging Human Dental Pulp.

PubMed

Couve, E; Lovera, M; Suzuki, K; Schmachtenberg, O

2018-03-01

Schwann cells are glial cells that support axonal development, maintenance, defense, and regeneration in the peripheral nervous system. There is limited knowledge regarding the organization, plasticity, and aging of Schwann cells within the dental pulp in adult permanent teeth. The present study sought to relate changes in the pattern of Schwann cell phenotypes between young and old adult teeth with neuronal, immune, and vascular components of the dental pulp. Schwann cells are shown to form a prominent glial network at the dentin-pulp interface, consisting of nonmyelinating and myelinating phenotypes, forming a multicellular neuroimmune interface in association with nerve fibers and dendritic cells. Schwann cell phenotypes are recognized by the expression of S100, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), Sox10, GAP43, and p75NTR markers. In young adult teeth, a dense population of nonmyelinating Schwann cells projects processes in close association with sensory nerve terminals through the odontoblast layer, reaching the adjacent predentin/dentin domain. While GAP43 and p75NTR are highly expressed in nonmyelinating Schwann cells from young adult teeth, the presence of these markers declines significantly in old adult teeth. Myelinated axons, identified by MBP expression, are mainly present at the Raschkow plexus and within nerve bundles in the dental pulp, but their density is significantly reduced in old adult versus young adult teeth. These data reveal age-related changes within the glial network of the dental pulp, in association with a reduction of coronal dental pulp innervation in old adult versus young adult teeth. The prominence of Schwann cells as a cellular component at the dentin-pulp interface supports the notion that their association with sensory nerve terminals and immune system components forms part of an integrated multicellular barrier for defense against pathogens and dentin repair.

Possible involvement of TLRs and hemichannels in stress-induced CNS dysfunction via mastocytes, and glia activation.

PubMed

Aguirre, Adam; Maturana, Carola J; Harcha, Paloma A; Sáez, Juan C

2013-01-01

In the central nervous system (CNS), mastocytes and glial cells (microglia, astrocytes and oligodendrocytes) function as sensors of neuroinflammatory conditions, responding to stress triggers or becoming sensitized to subsequent proinflammatory challenges. The corticotropin-releasing hormone and glucocorticoids are critical players in stress-induced mastocyte degranulation and potentiation of glial inflammatory responses, respectively. Mastocytes and glial cells express different toll-like receptor (TLR) family members, and their activation via proinflammatory molecules can increase the expression of connexin hemichannels and pannexin channels in glial cells. These membrane pores are oligohexamers of the corresponding protein subunits located in the cell surface. They allow ATP release and Ca(2+) influx, which are two important elements of inflammation. Consequently, activated microglia and astrocytes release ATP and glutamate, affecting myelinization, neuronal development, and survival. Binding of ligands to TLRs induces a cascade of intracellular events leading to activation of several transcription factors that regulate the expression of many genes involved in inflammation. During pregnancy, the previous responses promoted by viral infections and other proinflammatory conditions are common and might predispose the offspring to develop psychiatric disorders and neurological diseases. Such disorders could eventually be potentiated by stress and might be part of the etiopathogenesis of CNS dysfunctions including autism spectrum disorders and schizophrenia.

Immunological Demyelination Triggers Macrophage/Microglial Cells Activation without Inducing Astrogliosis

PubMed Central

Sears-Kraxberger, Ilse; Keirstead, Hans S.

2013-01-01

The glial scar formed by reactive astrocytes and axon growth inhibitors associated with myelin play important roles in the failure of axonal regeneration following central nervous system (CNS) injury. Our laboratory has previously demonstrated that immunological demyelination of the CNS facilitates regeneration of severed axons following spinal cord injury. In the present study, we evaluate whether immunological demyelination is accompanied with astrogliosis. We compared the astrogliosis and macrophage/microglial cell responses 7 days after either immunological demyelination or a stab injury to the dorsal funiculus. Both lesions induced a strong activated macrophage/microglial cells response which was significantly higher within regions of immunological demyelination. However, immunological demyelination regions were not accompanied by astrogliosis compared to stab injury that induced astrogliosis which extended several millimeters above and below the lesions, evidenced by astroglial hypertrophy, formation of a glial scar, and upregulation of intermediate filaments glial fibrillary acidic protein (GFAP). Moreover, a stab or a hemisection lesion directly within immunological demyelination regions did not induced astrogliosis within the immunological demyelination region. These results suggest that immunological demyelination creates a unique environment in which astrocytes do not form a glial scar and provides a unique model to understand the putative interaction between astrocytes and activated macrophage/microglial cells. PMID:24319469

Low levels of citrin (SLC25A13) expression in adult mouse brain restricted to neuronal clusters.

PubMed

Contreras, Laura; Urbieta, Almudena; Kobayashi, Keiko; Saheki, Takeyori; Satrústegui, Jorgina

2010-04-01

The mitochondrial aspartate-glutamate carriers (AGC) aralar (SLC25A12) and citrin (SLC25A13) are components of the malate aspartate shuttle (MAS), a major intracellular pathway to transfer reducing equivalents from NADH to the mitochondrial matrix. Aralar is the main AGC isoform present in the adult brain, and it is expressed mainly in neurons. To search for the other AGC isoform, citrin, in brain glial cells, we used a citrin knockout mouse in which the lacZ gene was inserted into the citrin locus as reporter gene. In agreement with the low citrin levels known to be present in the adult mouse brain, beta-galactosidase expression was very low. Surprisingly, unlike the case with astroglial cultures that express citrin, no beta-galactosidase was found in brain glial cells. It was confined to neuronal cells within discrete neuronal clusters. Double-immunolabelling experiments showed that beta-galactosidase colocalized not with glial cell markers but with the pan-neuronal marker NeuN. The deep cerebellar nuclei and a few midbrain nuclei (reticular tegmental pontine nuclei; magnocellular red nuclei) were the regions where beta-galactosidase expression was highest, and it was up-regulated in fasted mice, as was also the case for liver beta-galactosidase. The results support the notion that glial cells have much lower AGC levels and MAS activity than neurons. (c) 2009 Wiley-Liss, Inc.

Total numbers of neurons and glial cells in cortex and basal ganglia of aged brains with Down syndrome--a stereological study.

PubMed

Karlsen, Anna Schou; Pakkenberg, Bente

2011-11-01

The total numbers of neurons and glial cells in the neocortex and basal ganglia in adults with Down syndrome (DS) were estimated with design-based stereological methods, providing quantitative data on brains affected by delayed development and accelerated aging. Cell numbers, volume of regions, and densities of neurons and glial cell subtypes were estimated in brains from 4 female DS subjects (mean age 66 years) and 6 female controls (mean age 70 years). The DS subjects were estimated to have about 40% fewer neocortical neurons in total (11.1 × 10(9) vs. 17.8 × 10(9), 2p ≤ 0.001) and almost 30% fewer neocortical glial cells with no overlap to controls (12.8 × 10(9) vs. 18.2 × 10(9), 2p = 0.004). In contrast, the total number of neurons in the basal ganglia was the same in the 2 groups, whereas the number of oligodendrocytes in the basal ganglia was reduced by almost 50% in DS (405 × 10(6) vs. 816 × 10(6), 2p = 0.01). We conclude that trisomy 21 affects cortical structures more than central gray matter emphasizing the differential impairment of brain development. Despite concomitant Alzheimer-like pathology, the neurodegenerative outcome in a DS brain deviates from common Alzheimer disease.

Transplantation of autologous bone marrow-derived mesenchymal stem cells for traumatic brain injury☆

PubMed Central

Jiang, Jindou; Bu, Xingyao; Liu, Meng; Cheng, Peixun

2012-01-01

Results from the present study demonstrated that transplantation of autologous bone marrow-derived mesenchymal stem cells into the lesion site in rat brain significantly ameliorated brain tissue pathological changes and brain edema, attenuated glial cell proliferation, and increased brain-derived neurotrophic factor expression. In addition, the number of cells double-labeled for 5-bromodeoxyuridine/glial fibrillary acidic protein and cells expressing nestin increased. Finally, blood vessels were newly generated, and the rats exhibited improved motor and cognitive functions. These results suggested that transplantation of autologous bone marrow-derived mesenchymal stem cells promoted brain remodeling and improved neurological functions following traumatic brain injury. PMID:25806058

GABA and Glutamate Uptake and Metabolism in Retinal Glial (Müller) Cells

PubMed Central

Bringmann, Andreas; Grosche, Antje; Pannicke, Thomas; Reichenbach, Andreas

2013-01-01

Müller cells, the principal glial cells of the retina, support the synaptic activity by the uptake and metabolization of extracellular neurotransmitters. Müller cells express uptake and exchange systems for various neurotransmitters including glutamate and γ-aminobutyric acid (GABA). Müller cells remove the bulk of extracellular glutamate in the inner retina and contribute to the glutamate clearance around photoreceptor terminals. By the uptake of glutamate, Müller cells are involved in the shaping and termination of the synaptic activity, particularly in the inner retina. Reactive Müller cells are neuroprotective, e.g., by the clearance of excess extracellular glutamate, but may also contribute to neuronal degeneration by a malfunctioning or even reversal of glial glutamate transporters, or by a downregulation of the key enzyme, glutamine synthetase. This review summarizes the present knowledge about the role of Müller cells in the clearance and metabolization of extracellular glutamate and GABA. Some major pathways of GABA and glutamate metabolism in Müller cells are described; these pathways are involved in the glutamate-glutamine cycle of the retina, in the defense against oxidative stress via the production of glutathione, and in the production of substrates for the neuronal energy metabolism. PMID:23616782

Brain and Peripheral Atypical Inflammatory Mediators Potentiate Neuroinflammation and Neurodegeneration.

PubMed

Kempuraj, Duraisamy; Thangavel, Ramasamy; Selvakumar, Govindhasamy P; Zaheer, Smita; Ahmed, Mohammad E; Raikwar, Sudhanshu P; Zahoor, Haris; Saeed, Daniyal; Natteru, Prashant A; Iyer, Shankar; Zaheer, Asgar

2017-01-01

Neuroinflammatory response is primarily a protective mechanism in the brain. However, excessive and chronic inflammatory responses can lead to deleterious effects involving immune cells, brain cells and signaling molecules. Neuroinflammation induces and accelerates pathogenesis of Parkinson's disease (PD), Alzheimer's disease (AD) and Multiple sclerosis (MS). Neuroinflammatory pathways are indicated as novel therapeutic targets for these diseases. Mast cells are immune cells of hematopoietic origin that regulate inflammation and upon activation release many proinflammatory mediators in systemic and central nervous system (CNS) inflammatory conditions. In addition, inflammatory mediators released from activated glial cells induce neurodegeneration in the brain. Systemic inflammation-derived proinflammatory cytokines/chemokines and other factors cause a breach in the blood brain-barrier (BBB) thereby allowing for the entry of immune/inflammatory cells including mast cell progenitors, mast cells and proinflammatory cytokines and chemokines into the brain. These peripheral-derived factors and intrinsically generated cytokines/chemokines, α-synuclein, corticotropin-releasing hormone (CRH), substance P (SP), beta amyloid 1-42 (Aβ1-42) peptide and amyloid precursor proteins can activate glial cells, T-cells and mast cells in the brain can induce additional release of inflammatory and neurotoxic molecules contributing to chronic neuroinflammation and neuronal death. The glia maturation factor (GMF), a proinflammatory protein discovered in our laboratory released from glia, activates mast cells to release inflammatory cytokines and chemokines. Chronic increase in the proinflammatory mediators induces neurotoxic Aβ and plaque formation in AD brains and neurodegeneration in PD brains. Glial cells, mast cells and T-cells can reactivate each other in neuroinflammatory conditions in the brain and augment neuroinflammation. Further, inflammatory mediators from the brain can also enter into the peripheral system through defective BBB, recruit immune cells into the brain, and exacerbate neuroinflammation. We suggest that mast cell-associated inflammatory mediators from systemic inflammation and brain could augment neuroinflammation and neurodegeneration in the brain. This review article addresses the role of some atypical inflammatory mediators that are associated with mast cell inflammation and their activation of glial cells to induce neurodegeneration.

Extracellular Electrophysiological Measurements of Cooperative Signals in Astrocytes Populations

PubMed Central

Mestre, Ana L. G.; Inácio, Pedro M. C.; Elamine, Youssef; Asgarifar, Sanaz; Lourenço, Ana S.; Cristiano, Maria L. S.; Aguiar, Paulo; Medeiros, Maria C. R.; Araújo, Inês M.; Ventura, João; Gomes, Henrique L.

2017-01-01

Astrocytes are neuroglial cells that exhibit functional electrical properties sensitive to neuronal activity and capable of modulating neurotransmission. Thus, electrophysiological recordings of astroglial activity are very attractive to study the dynamics of glial signaling. This contribution reports on the use of ultra-sensitive planar electrodes combined with low noise and low frequency amplifiers that enable the detection of extracellular signals produced by primary cultures of astrocytes isolated from mouse cerebral cortex. Recorded activity is characterized by spontaneous bursts comprised of discrete signals with pronounced changes on the signal rate and amplitude. Weak and sporadic signals become synchronized and evolve with time to higher amplitude signals with a quasi-periodic behavior, revealing a cooperative signaling process. The methodology presented herewith enables the study of ionic fluctuations of population of cells, complementing the single cells observation by calcium imaging as well as by patch-clamp techniques. PMID:29109679

Extracellular Electrophysiological Measurements of Cooperative Signals in Astrocytes Populations.

PubMed

Mestre, Ana L G; Inácio, Pedro M C; Elamine, Youssef; Asgarifar, Sanaz; Lourenço, Ana S; Cristiano, Maria L S; Aguiar, Paulo; Medeiros, Maria C R; Araújo, Inês M; Ventura, João; Gomes, Henrique L

2017-01-01

Astrocytes are neuroglial cells that exhibit functional electrical properties sensitive to neuronal activity and capable of modulating neurotransmission. Thus, electrophysiological recordings of astroglial activity are very attractive to study the dynamics of glial signaling. This contribution reports on the use of ultra-sensitive planar electrodes combined with low noise and low frequency amplifiers that enable the detection of extracellular signals produced by primary cultures of astrocytes isolated from mouse cerebral cortex. Recorded activity is characterized by spontaneous bursts comprised of discrete signals with pronounced changes on the signal rate and amplitude. Weak and sporadic signals become synchronized and evolve with time to higher amplitude signals with a quasi-periodic behavior, revealing a cooperative signaling process. The methodology presented herewith enables the study of ionic fluctuations of population of cells, complementing the single cells observation by calcium imaging as well as by patch-clamp techniques.

Morphofunctional aspects of the blood-brain barrier.

PubMed

Nico, Beatrice; Ribatti, Domenico

2012-01-01

The blood-brain barrier (BBB) selectively controls the homeostasis of the Central Nervous System (CNS) environment by the specific structural and biochemical features of the endothelial cells, pericytes and glial endfeet, which represent the cellular components of the mature BBB. Endothelial tight junctions (TJs) are the most important structural component of the BBB, and molecular alteration in the phosphorylation state of some TJs proteins, like ZO-1 or occludin, are crucial in determining alterations in the control of BBB vascular permeability. Astrocytes endfeet enveloping the vessels wall, are considered important in the induction and maintenance of the BBB, through secretion of soluble factors, which modulate the expression of enzymatic complexes and antigens by endothelial cells and TJs - associated proteins. Moreover, astrocytes control water flux at BBB site by expressing a specific water channel, namely aquaporin-4 (AQP4), involved in the molecular composition of the orthogonal particles arrays (OAPs) on the perivascular glial endfeet and tightly coupled with the maintenance of the BBB integrity. Disruption of the BBB is a consistent event occurring in the development of several CNS diseases, including demyelinating lesions in the course of relapsing multiple sclerosis, stroke, Duchenne muscular dystrophy (DMD), but also mechanical injures, neurological insults, septic encephalopathy, brain tumors, permanent ischemia or transient ischemia followed by reperfusion. In most cases, these pathological conditions are associated with an increase in microvascular permeability, vasogenic edema, swollen atrocyte endfeet, and BBB disruption.

Anti-aging effects of guanosine in glial cells.

PubMed

Souza, Débora Guerini; Bellaver, Bruna; Bobermin, Larissa Daniele; Souza, Diogo Onofre; Quincozes-Santos, André

2016-12-01

Guanosine, a guanine-based purine, has been shown to exert beneficial roles in in vitro and in vivo injury models of neural cells. Guanosine is released from astrocytes and modulates important astroglial functions, including glutamatergic metabolism, antioxidant, and anti-inflammatory activities. Astrocytes are crucial for regulating the neurotransmitter system and synaptic information processes, ionic homeostasis, energy metabolism, antioxidant defenses, and the inflammatory response. Aging is a natural process that induces numerous changes in the astrocyte functionality. Thus, the search for molecules able to reduce the glial dysfunction associated with aging may represent an approach for avoiding the onset of age-related neurological diseases. Hence, the aim of this study was to evaluate the anti-aging effects of guanosine, using primary astrocyte cultures from newborn, adult, and aged Wistar rats. Concomitantly, we evaluated the role of heme oxygenase 1 (HO-1) in guanosine-mediated glioprotection. We observed age-dependent changes in glutamate uptake, glutamine synthetase (GS) activity, the glutathione (GSH) system, pro-inflammatory cytokine (tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β)) release, and the transcriptional activity of nuclear factor kB (NFkB), which were prevented by guanosine in an HO-1-dependent manner. Our findings suggest guanosine to be a promising therapeutic agent able to provide glioprotection during the aging process. Thus, this study contributes to the understanding of the cellular and molecular mechanisms of guanosine in the aging process.

Enteric nervous system specific deletion of Foxd3 disrupts glial cell differentiation and activates compensatory enteric progenitors.

PubMed

Mundell, Nathan A; Plank, Jennifer L; LeGrone, Alison W; Frist, Audrey Y; Zhu, Lei; Shin, Myung K; Southard-Smith, E Michelle; Labosky, Patricia A

2012-03-15

The enteric nervous system (ENS) arises from the coordinated migration, expansion and differentiation of vagal and sacral neural crest progenitor cells. During development, vagal neural crest cells enter the foregut and migrate in a rostro-to-caudal direction, colonizing the entire gastrointestinal tract and generating the majority of the ENS. Sacral neural crest contributes to a subset of enteric ganglia in the hindgut, colonizing the colon in a caudal-to-rostral wave. During this process, enteric neural crest-derived progenitors (ENPs) self-renew and begin expressing markers of neural and glial lineages as they populate the intestine. Our earlier work demonstrated that the transcription factor Foxd3 is required early in neural crest-derived progenitors for self-renewal, multipotency and establishment of multiple neural crest-derived cells and structures including the ENS. Here, we describe Foxd3 expression within the fetal and postnatal intestine: Foxd3 was strongly expressed in ENPs as they colonize the gastrointestinal tract and was progressively restricted to enteric glial cells. Using a novel Ednrb-iCre transgene to delete Foxd3 after vagal neural crest cells migrate into the midgut, we demonstrated a late temporal requirement for Foxd3 during ENS development. Lineage labeling of Ednrb-iCre expressing cells in Foxd3 mutant embryos revealed a reduction of ENPs throughout the gut and loss of Ednrb-iCre lineage cells in the distal colon. Although mutant mice were viable, defects in patterning and distribution of ENPs were associated with reduced proliferation and severe reduction of glial cells derived from the Ednrb-iCre lineage. Analyses of ENS-lineage and differentiation in mutant embryos suggested activation of a compensatory population of Foxd3-positive ENPs that did not express the Ednrb-iCre transgene. Our findings highlight the crucial roles played by Foxd3 during ENS development including progenitor proliferation, neural patterning, and glial differentiation and may help delineate distinct molecular programs controlling vagal versus sacral neural crest development. Copyright © 2012 Elsevier Inc. All rights reserved.

Ultrastructure of neurovascular changes in human diabetic retinopathy.

PubMed

Fehér, János; Taurone, Samanta; Spoletini, Marialuisa; Biró, Zsolt; Varsányi, Balázs; Scuderi, Gianluca; Orlando, Maria Patrizia; Turchetta, Rosaria; Micera, Alessandra; Artico, Marco

2018-01-01

The previous concept regarding diabetic retinopathy assigned a primary role to hyperglycemia-induced microvascular alterations, while neuronal and glial abnormalities were considered to be secondary to either ischemia or exudation. The aim of this study was to reveal the potential role of neuronal and glial cells in initial and advanced alterations of the retinopathy in human type 2 diabetes. Electron microscopy and histochemical studies were performed on 38 surgically removed human eyes (28 obtained from diabetic patients and 10 from non-diabetic patients). Morphometric analysis of basement membrane material and lipids was performed. An accumulation of metabolic by-products was found in the capillary wall with aging: this aspect was significantly more pronounced in diabetics. Müller glial cells were found to contribute to alterations of the capillary wall and to occlusion, as well as to the development of proliferative retinopathy and cystoid degeneration of the retina. Our results showed morphological evidence regarding the role of neuronal and glial cells in the pathology of diabetic retinopathy, prior and in addition to microangiopathy. These morphological findings support a neurovascular pathogenesis at the origin of diabetic retinopathy, thus the current treatment approach should be completed by neuroprotective measures.

Ebselen by modulating oxidative stress improves hypoxia-induced macroglial Müller cell and vascular injury in the retina.

PubMed

Tan, Sih Min; Deliyanti, Devy; Figgett, William A; Talia, Dean M; de Haan, Judy B; Wilkinson-Berka, Jennifer L

2015-07-01

Oxidative stress is an important contributor to glial and vascular cell damage in ischemic retinopathies. We hypothesized that ebselen via its ability to reduce reactive oxygen species (ROS) and augment nuclear factor-like 2 (Nrf2) anti-oxidants would attenuate hypoxia-induced damage to macroglial Müller cells and also lessen retinal vasculopathy. Primary cultures of rat Müller cells were exposed to normoxia (21% O2), hypoxia (0.5% O2) and ebselen (2.5 μM) for up to 72 h. Oxygen-induced retinopathy (OIR) was induced in C57BL/6J mice while control mice were housed in room air. Mice received vehicle (saline, 5% dimethyl sulfoxide) or ebselen (10 mg/kg) each day between postnatal days 6-18. In cultured Müller cells, flow cytometry for dihydroethidium revealed that ebselen reduced the hypoxia-induced increase in ROS levels, whilst increasing the expression of Nrf2-regulated anti-oxidant genes, heme oxygenase 1, glutathione peroxidase-1, NAD(P)H dehydrogenase quinone oxidoreductase 1 and glutamate-cysteine ligase. Moreover, in Müller cells, ebselen reduced the hypoxia-induced increase in protein levels of pro-angiogenic and pro-inflammatory factors including vascular endothelial growth factor, interleukin-6, monocyte chemoattractant-protein 1 and intercellular adhesion molecule-1, and the mRNA levels of glial fibrillary acidic protein (GFAP), a marker of Müller cell injury. Ebselen improved OIR by attenuating capillary vaso-obliteration and neovascularization and a concomitant reduction in Müller cell gliosis and GFAP. We conclude that ebselen protects against hypoxia-induced injury of retinal Müller cells and the microvasculature, which is linked to its ability to reduce oxidative stress, vascular damaging factors and inflammation. Agents such as ebselen may be potential treatments for retinopathies that feature oxidative stress-mediated damage to glia and the microvasculature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Immunoreactivity for GABA, GAD65, GAD67 and Bestrophin-1 in the meninges and the choroid plexus: implications for non-neuronal sources for GABA in the developing mouse brain.

PubMed

Tochitani, Shiro; Kondo, Shigeaki

2013-01-01

Neural progenitors in the developing neocortex, neuroepithelial cells and radial glial cells, have a bipolar shape with a basal process contacting the basal membrane of the meninge and an apical plasma membrane facing the lateral ventricle, which the cerebrospinal fluid is filled with. Recent studies revealed that the meninges and the cerebrospinal fluid have certain roles to regulate brain development. γ-aminobutyric acid (GABA) is a neurotransmitter which appears first during development and works as a diffusible factor to regulate the properties of neural progenitors. In this study, we examined whether GABA can be released from the meninges and the choroid plexus in the developing mouse brain. Immunohistochemical analyses showed that glutamic acid decarboxylase 65 and 67 (GAD65 and GAD67), both of which are GABA-synthesizing enzymes, are expressed in the meninges. The epithelial cells in the choroid plexus express GAD65. GABA immunoreactivity could be observed beneath the basal membrane of the meninge and in the epithelial cells of the choroid plexus. Expression analyses on Bestrophin-1, which is known as a GABA-permeable channel in differentiated glial cells, suggested that the cells in the meninges and the epithelial cells in the choroid plexus have the channels able to permeate non-synaptic GABA into the extracellular space. Further studies showed that GAD65/67-expressing meningeal cells appear in a manner with rostral to caudal and lateral to dorsal gradient to cover the entire neocortex by E14.5 during development, while the cells in the choroid plexus in the lateral ventricle start to express GAD65 on E11-E12, the time when the choroid plexus starts to develop in the developing brain. These results totally suggest that the meninges and the choroid plexus can work as non-neuronal sources for ambient GABA which can modulate the properties of neural progenitors during neocortical development.

Immunoreactivity for GABA, GAD65, GAD67 and Bestrophin-1 in the Meninges and the Choroid Plexus: Implications for Non-Neuronal Sources for GABA in the Developing Mouse Brain

PubMed Central

Tochitani, Shiro; Kondo, Shigeaki

2013-01-01

Neural progenitors in the developing neocortex, neuroepithelial cells and radial glial cells, have a bipolar shape with a basal process contacting the basal membrane of the meninge and an apical plasma membrane facing the lateral ventricle, which the cerebrospinal fluid is filled with. Recent studies revealed that the meninges and the cerebrospinal fluid have certain roles to regulate brain development. γ-aminobutyric acid (GABA) is a neurotransmitter which appears first during development and works as a diffusible factor to regulate the properties of neural progenitors. In this study, we examined whether GABA can be released from the meninges and the choroid plexus in the developing mouse brain. Immunohistochemical analyses showed that glutamic acid decarboxylase 65 and 67 (GAD65 and GAD67), both of which are GABA-synthesizing enzymes, are expressed in the meninges. The epithelial cells in the choroid plexus express GAD65. GABA immunoreactivity could be observed beneath the basal membrane of the meninge and in the epithelial cells of the choroid plexus. Expression analyses on Bestrophin-1, which is known as a GABA-permeable channel in differentiated glial cells, suggested that the cells in the meninges and the epithelial cells in the choroid plexus have the channels able to permeate non-synaptic GABA into the extracellular space. Further studies showed that GAD65/67-expressing meningeal cells appear in a manner with rostral to caudal and lateral to dorsal gradient to cover the entire neocortex by E14.5 during development, while the cells in the choroid plexus in the lateral ventricle start to express GAD65 on E11–E12, the time when the choroid plexus starts to develop in the developing brain. These results totally suggest that the meninges and the choroid plexus can work as non-neuronal sources for ambient GABA which can modulate the properties of neural progenitors during neocortical development. PMID:23437266

Non-Neuronal Cells Are Required to Mediate the Effects of Neuroinflammation: Results from a Neuron-Enriched Culture System

PubMed Central

Hui, Chin Wai; Zhang, Yang; Herrup, Karl

2016-01-01

Chronic inflammation is associated with activated microglia and reactive astrocytes and plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer’s. Both in vivo and in vitro studies have demonstrated that inflammatory cytokine responses to immune challenges contribute to neuronal death during neurodegeneration. In order to investigate the role of glial cells in this phenomenon, we developed a modified method to remove the non-neuronal cells in primary cultures of E16.5 mouse cortex. We modified previously reported methods as we found that a brief treatment with the thymidine analog, 5-fluorodeoxyuridine (FdU), is sufficient to substantially deplete dividing non-neuronal cells in primary cultures. Cell cycle and glial markers confirm the loss of ~99% of all microglia, astrocytes and oligodendrocyte precursor cells (OPCs). More importantly, under this milder treatment, the neurons suffered neither cell loss nor any morphological defects up to 2.5 weeks later; both pre- and post-synaptic markers were retained. Further, neurons in FdU-treated cultures remained responsive to excitotoxicity induced by glutamate application. The immunobiology of the FdU culture, however, was significantly changed. Compared with mixed culture, the protein levels of NFκB p65 and the gene expression of several cytokine receptors were altered. Individual cytokines or conditioned medium from β-amyloid-stimulated THP-1 cells that were, potent neurotoxins in normal, mixed cultures, were virtually inactive in the absence of glial cells. The results highlight the importance of our glial-depleted culture system and identifies and offer unexpected insights into the complexity of -brain neuroinflammation. PMID:26788729

Insulin-induced exocytosis regulates the cell surface level of low-density lipoprotein-related protein-1 in Müller Glial cells.

PubMed

Actis Dato, Virginia; Grosso, Rubén A; Sánchez, María C; Fader, Claudio M; Chiabrando, Gustavo A

2018-05-15

Low-density lipoprotein (LDL) receptor-related protein-1 (LRP1) is expressed in retinal Müller glial cells (MGCs) and regulates intracellular translocation to the plasma membrane (PM) of the membrane proteins involved in cellular motility and activity. Different functions of MGCs may be influenced by insulin, including the removal of extracellular glutamate in the retina. In the present work, we investigated whether insulin promotes LRP1 translocation to the PM in the Müller glial-derived cell line MIO-M1 (human retinal Müller glial cell-derived cell line). We demonstrated that LRP1 is stored in small vesicles containing an approximate size of 100 nm (mean diameter range of 100-120 nm), which were positive for sortilin and VAMP2, and also incorporated GLUT4 when it was transiently transfected. Next, we observed that LRP1 translocation to the PM was promoted by insulin-regulated exocytosis through intracellular activation of the IR/PI 3 K/Akt axis and Rab-GTPase proteins such as Rab8A and Rab10. In addition, these Rab-GTPases regulated both the constitutive and insulin-induced LRP1 translocation to the PM. Finally, we found that dominant-negative Rab8A and Rab10 mutants impaired insulin-induced intracellular signaling of the IR/PI3K/Akt axis, suggesting that these GTPase proteins as well as the LRP1 level at the cell surface are involved in insulin-induced IR activation. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Preferential and Increased Uptake of Hydroxyl-Terminated PAMAM Dendrimers by Activated Microglia in Rabbit Brain Mixed Glial Culture.

PubMed

Alnasser, Yossef; Kambhampati, Siva P; Nance, Elizabeth; Rajbhandari, Labchan; Shrestha, Shiva; Venkatesan, Arun; Kannan, Rangaramanujam M; Kannan, Sujatha

2018-04-27

Polyamidoamine (PAMAM) dendrimers are multifunctional nanoparticles with tunable physicochemical features, making them promising candidates for targeted drug delivery in the central nervous system (CNS). Systemically administered dendrimers have been shown to localize in activated glial cells, which mediate neuroinflammation in the CNS. These dendrimers delivered drugs specifically to activated microglia, producing significant neurological improvements in multiple brain injury models, including in a neonatal rabbit model of cerebral palsy. To gain further insight into the mechanism of dendrimer cell uptake, we utilized an in vitro model of primary glial cells isolated from newborn rabbits to assess the differences in hydroxyl-terminated generation 4 PAMAM dendrimer (D4-OH) uptake by activated and non-activated glial cells. We used fluorescently-labelled D4-OH (D-Cy5) as a tool for investigating the mechanism of dendrimer uptake. D4-OH PAMAM dendrimer uptake was determined by fluorescence quantification using confocal microscopy and flow cytometry. Our results indicate that although microglial cells in the mixed cell population demonstrate early uptake of dendrimers in this in vitro system, activated microglia take up more dendrimer compared to resting microglia. Astrocytes showed delayed and limited uptake. We also illustrated the differences in mechanism of uptake between resting and activated microglia using different pathway inhibitors. Both resting and activated microglia primarily employed endocytotic pathways, which are enhanced in activated microglial cells. Additionally, we demonstrated that hydroxyl terminated dendrimers are taken up by primary microglia using other mechanisms including pinocytosis, caveolae, and aquaporin channels for dendrimer uptake.

Amplification of progenitors in the mammalian telencephalon includes a new radial glial cell type.

PubMed

Pilz, Gregor-Alexander; Shitamukai, Atsunori; Reillo, Isabel; Pacary, Emilie; Schwausch, Julia; Stahl, Ronny; Ninkovic, Jovica; Snippert, Hugo J; Clevers, Hans; Godinho, Leanne; Guillemot, Francois; Borrell, Victor; Matsuzaki, Fumio; Götz, Magdalena

2013-01-01

The mechanisms governing the expansion of neuron number in specific brain regions are still poorly understood. Enlarged neuron numbers in different species are often anticipated by increased numbers of progenitors dividing in the subventricular zone. Here we present live imaging analysis of radial glial cells and their progeny in the ventral telencephalon, the region with the largest subventricular zone in the murine brain during neurogenesis. We observe lineage amplification by a new type of progenitor, including bipolar radial glial cells dividing at subapical positions and generating further proliferating progeny. The frequency of this new type of progenitor is increased not only in larger clones of the mouse lateral ganglionic eminence but also in cerebral cortices of gyrated species, and upon inducing gyrification in the murine cerebral cortex. This implies key roles of this new type of radial glia in ontogeny and phylogeny.

Identification of ganglion cell neurites in human subretinal and epiretinal membranes

PubMed Central

Lewis, Geoffrey P; Betts, Kellen E; Sethi, Charanjit S; Charteris, David G; Lesnik‐Oberstein, Sarit Y; Avery, Robert L; Fisher, Steven K

2007-01-01

Aim To determine whether neural elements are present in subretinal and epiretinal proliferative vitreoretinopathy (PVR) membranes as well as in diabetic, fibrovascular membranes removed from patients during vitrectomy surgery. Methods Human subretinal and epiretinal membranes of varying durations were immunolabelled with different combinations of antibodies to glial fibrillary acidic protein, vimentin, neurofilament protein and laminin. Results Anti‐neurofilament‐labelled neurites from presumptive ganglion cells were frequently found in epiretinal membranes and occasionally found in subretinal membranes. In addition, the neurites were only observed in regions that also contained glial processes. Conclusions These data demonstrate that neuronal processes are commonly found in human peri‐retinal cellular membranes similar to that demonstrated in animal models. These data also suggest that glial cells growing out of the neural retina form a permissive substrate for neurite growth and thus may hold clues to factors that support this growth. PMID:17108012

Leptin regulates glutamate and glucose transporters in hypothalamic astrocytes

PubMed Central

Fuente-Martín, Esther; García-Cáceres, Cristina; Granado, Miriam; de Ceballos, María L.; Sánchez-Garrido, Miguel Ángel; Sarman, Beatrix; Liu, Zhong-Wu; Dietrich, Marcelo O.; Tena-Sempere, Manuel; Argente-Arizón, Pilar; Díaz, Francisca; Argente, Jesús; Horvath, Tamas L.; Chowen, Julie A.

2012-01-01

Glial cells perform critical functions that alter the metabolism and activity of neurons, and there is increasing interest in their role in appetite and energy balance. Leptin, a key regulator of appetite and metabolism, has previously been reported to influence glial structural proteins and morphology. Here, we demonstrate that metabolic status and leptin also modify astrocyte-specific glutamate and glucose transporters, indicating that metabolic signals influence synaptic efficacy and glucose uptake and, ultimately, neuronal function. We found that basal and glucose-stimulated electrical activity of hypothalamic proopiomelanocortin (POMC) neurons in mice were altered in the offspring of mothers fed a high-fat diet. In adulthood, increased body weight and fasting also altered the expression of glucose and glutamate transporters. These results demonstrate that whole-organism metabolism alters hypothalamic glial cell activity and suggest that these cells play an important role in the pathology of obesity. PMID:23064363

Lentiviral-mediated targeted NF-kappaB blockade in dorsal spinal cord glia attenuates sciatic nerve injury-induced neuropathic pain in the rat.

PubMed

Meunier, Alice; Latrémolière, Alban; Dominguez, Elisa; Mauborgne, Annie; Philippe, Stéphanie; Hamon, Michel; Mallet, Jacques; Benoliel, Jean-Jacques; Pohl, Michel

2007-04-01

Neuropathic pain developing after peripheral nerve injury is associated with altered neuronal and glial cell functions in the spinal cord. Activated glia produces algogenic mediators, exacerbating pain. Among the different intracellular pathways possibly involved in the modified glial function, the nuclear factor kappaB (NF-kappaB) system is of particular interest, as numerous genes encoding inflammation- and pain-related molecules are controlled by this transcription factor. NF-kappaB is a pleiotropic factor also involved in central nervous system homeostasy. To study its role in chronic pain, it is thus essential to inhibit the NF-kappaB pathway selectively in activated spinal glial cells. Here, we show that when restricted to spinal cord and targeted to glial cells, lentiviral vector-mediated delivery of NF-kappaB super- repressor IkappaBalpha resulted in an inhibition of the NF-kappaB pathway activated in the rat spinal cord after sciatic nerve injury (chronic constriction injury, CCI). Concomitantly, IkappaBalpha overproduction prevented the enhanced expression of interleukin-6 and of inducible nitric oxide synthase associated with chronic constriction injury and resulted in prolonged antihyperalgesic and antiallodynic effects. These data show that targeted blockade of NF-kappaB activity in spinal glia efficiently alleviates pain behavior in CCI rats, demonstrating the active participation of the glial NF-kappaB pathway in the development of neuropathic pain after peripheral nerve injury.

Curcumin-loaded chitosan-alginate-STPP nanoparticles ameliorate memory deficits and reduce glial activation in pentylenetetrazol-induced kindling model of epilepsy.

PubMed

Hashemian, Mona; Anissian, Diana; Ghasemi-Kasman, Maryam; Akbari, Atefeh; Khalili-Fomeshi, Mohsen; Ghasemi, Shahram; Ahmadi, Fatemeh; Moghadamnia, Ali Akbar; Ebrahimpour, Anahita

2017-10-03

Despite several beneficial effects of curcumin, its medical application has been hampered due to low water solubility. To improve the aqueous solubility of curcumin, it has been loaded on chitosan (CS)-alginate (ALG) - sodium tripolyphosphate (STPP) nanoparticles (NPs). Then, the effect of curcumin NPs on memory improvement and glial activation was investigated in pentylenetetrazol (PTZ)-induced kindling model. Male NMRI mice have received the daily injection of curcumin NPs at dose of 12.5 or 25mg/kg. All interventions were injected intraperitoneally (i.p), 10days before PTZ administration and the injections were continued until 1h before each PTZ injection. Spatial learning and memory was evaluated using Morris water maze test after the 7th PTZ injection. Animals have received 10 injections of PTZ and then, brain tissues were removed for histological evaluation. Nissl staining was used to determine the level of cell death in hippocampus and immunostaining method was performed against NeuN and GFAP/Iba1 for assessment of neuronal density and glial activation respectively. Behavioral results showed that curcumin NPs exhibit anticonvulsant activity and prevent cognitive impairment in fully kindled animals. The level of cell death and glial activation reduced in animals which have received curcumin NPs compared to those received free curcumin. To conclude, these findings suggest that curcumin NPs effectively ameliorate memory impairment and attenuate the level of activated glial cells in a mice model of chronic epilepsy. Copyright © 2017. Published by Elsevier Inc.

Investigation of terahertz radiation influence on rat glial cells

PubMed Central

Borovkova, Mariia; Serebriakova, Maria; Fedorov, Viacheslav; Sedykh, Egor; Vaks, Vladimir; Lichutin, Alexander; Salnikova, Alina; Khodzitsky, Mikhail

2016-01-01

We studied an influence of continuous terahertz (THz) radiation (0.12 – 0.18 THz, average power density of 3.2 mW/cm2) on a rat glial cell line. A dose-dependent cytotoxic effect of THz radiation is demonstrated. After 1 minute of THz radiation exposure a relative number of apoptotic cells increased in 1.5 times, after 3 minutes it doubled. This result confirms the concept of biological hazard of intense THz radiation. Diagnostic applications of THz radiation can be restricted by the radiation power density and exposure time. PMID:28101417

The critical chemical and mechanical regulation of folic acid on neural engineering.

PubMed

Kim, Gloria B; Chen, Yongjie; Kang, Weibo; Guo, Jinshan; Payne, Russell; Li, Hui; Wei, Qiong; Baker, Julianne; Dong, Cheng; Zhang, Sulin; Wong, Pak Kin; Rizk, Elias B; Yan, Jiazhi; Yang, Jian

2018-04-03

The mandate of folic acid supplementation in grained products has reduced the occurrence of neural tube defects by one third in the U.S since its introduction by the Food and Drug Administration in 1998. However, the advantages and possible mechanisms of action of using folic acid for peripheral nerve engineering and neurological diseases still remain largely elusive. Herein, folic acid is described as an inexpensive and multifunctional niche component that modulates behaviors in different cells in the nervous system. The multiple benefits of modulation include: 1) generating chemotactic responses on glial cells, 2) inducing neurotrophin release, and 3) stimulating neuronal differentiation of a PC-12 cell system. For the first time, folic acid is also shown to enhance cellular force generation and global methylation in the PC-12 cells, thereby enabling both biomechanical and biochemical pathways to regulate neuron differentiation. These findings are evaluated in vivo for clinical translation. Our results suggest that folic acid-nerve guidance conduits may offer significant benefits as a low-cost, off-the-shelf product for reaching the functional recovery seen with autografts in large sciatic nerve defects. Consequently, folic acid holds great potential as a critical and convenient therapeutic intervention for neural engineering, regenerative medicine, medical prosthetics, and drug delivery. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heterogeneity and Fgf dependence of adult neural progenitors in the zebrafish telencephalon.

PubMed

Ganz, Julia; Kaslin, Jan; Hochmann, Sarah; Freudenreich, Dorian; Brand, Michael

2010-08-15

Adult telencephalic neurogenesis is a conserved trait of all vertebrates studied. It has been investigated in detail in rodents, but very little is known about the composition of neurogenic niches and the cellular nature of progenitors in nonmammalian vertebrates. To understand the components of the progenitor zones in the adult zebrafish telencephalon and the link between glial characteristics and progenitor state, we examined whether canonical glial markers are colocalized with proliferation markers. In the adult zebrafish telencephalon, we identify heterogeneous progenitors that reside in two distinct glial domains. We find that the glial composition of the progenitor zone is linked to its proliferative behavior. Analyzing both fast-cycling proliferating cells as well as slowly cycling progenitors, we find four distinct progenitor types characterized by differential expression of glial markers. Importantly, a significant proportion of progenitors do not display typical radial glia characteristics. By blocking or activating Fgf signaling by misexpression of a dominant negative Fgf-receptor 1 or Fgf8a, respectively, we find that ventral and dorsal progenitors in the telencephalon also differ in their requirement for Fgf signaling. Together with data on the expression of Fgf signaling components in the ventricular zone of the telencephalon, this suggests that Fgf signaling directly regulates proliferation of specific subsets of adult telencephalic progenitors in vivo. Taken together our results show that adult neural progenitor cells are heterogeneous with their respect to distribution into two distinct glial domains and their dependence upon Fgf signaling as a proliferative cue in the zebrafish telencephalon.

Glial architecture of the ghost shark (Callorhinchus milii, Holocephali, Chondrichthyes) as revealed by different immunohistochemical markers.

PubMed

Ari, Csilla; Kálmán, Mihály

2008-09-15

This article presents the first study on the glial architecture of a representative species of Holocephali, Callorhinchus milii (ghost shark). Holocephali are a small subclass of Chondrichthyes, with only a few extant genera, and those are considered to have a brain organization more similar to squalomorph sharks than to galeomorph sharks, skates, and rays. Three different astroglial markers--glial fibrillary acidic protein, S-100 protein, and glutamine synthetase (GS)--were investigated by immunohistochemical methods, applying both diaminobenzidine (DAB) and fluorescent techniques. They revealed similar glial structures, although most of them were detected by immunohistochemical reaction against GS and visualized by DAB. The predominant elements were radial ependymoglia spanning the area between the ventricular and meningeal surfaces, as in squalomorph sharks. Other similar features were the light appearance of myelinated neural tracts devoid of immunoreactivity, and the glial architecture of the reticular formation of the brain stem, cerebellum, and tectum, the latter with recognizable layers. The immunoreactivity of the vascular walls was similar; however, it is believed that different cell types form the blood-brain barrier in chimeras and in elasmobranchs. Some glial structures, however, resembled those of skates, rays, and galeomorph sharks. In C. milii astrocyte-like elements were observed in the telencephalon, using GS and S-100, although typical astrocyte-rich regions were not found. In some areas, especially the telencephalon, not only endfeet but also cell bodies were observed to be attached to the meningeal surface, with processes extending into the brain substance.

Environmental stress, ageing and glial cell senescence: a novel mechanistic link to Parkinson’s disease?

PubMed Central

Chinta, Shankar J; Lieu, Christopher A; DeMaria, Marco; Laberge, Remi-Martin; Campisi, Judith; Andersen, Julie K

2013-01-01

Exposure to environmental toxins is associated with a variety of age-related diseases including cancer and neurodegeneration. For example, in Parkinson’s disease (PD), chronic environmental exposure to certain toxins has been linked to the age-related development of neuropathology. Neuronal damage is believed to involve the induction of neuroinflammatory events as a consequence of glial cell activation. Cellular senescence is a potent anti-cancer mechanism that occurs in a number of proliferative cell types and causes the arrest of proliferation of cells at risk of malignant transformation following exposure to potentially oncogenic stimuli. With age, senescent cells accumulate and express a senescence-associated secretory phenotype (SASP; i.e. the robust secretion of many inflammatory cytokines, growth factors and proteases). Whereas cell senescence in peripheral tissues has been causally linked to a number of age-related pathologies, little is known about the induction of cellular senescence and the SASP in the brain. Based on recently reported findings, we propose that environmental stressors associated with PD may act in part by eliciting senescence and the SASP within non-neuronal glial cells in the ageing brain, thus contributing to the characteristic decline in neuronal integrity that occurs in this disorder. PMID:23600398

The Touch and Zap method for in vivo whole-cell patch recording of intrinsic and visual responses of cortical neurons and glial cells.

PubMed

Schramm, Adrien E; Marinazzo, Daniele; Gener, Thomas; Graham, Lyle J

2014-01-01

Whole-cell patch recording is an essential tool for quantitatively establishing the biophysics of brain function, particularly in vivo. This method is of particular interest for studying the functional roles of cortical glial cells in the intact brain, which cannot be assessed with extracellular recordings. Nevertheless, a reasonable success rate remains a challenge because of stability, recording duration and electrical quality constraints, particularly for voltage clamp, dynamic clamp or conductance measurements. To address this, we describe "Touch and Zap", an alternative method for whole-cell patch clamp recordings, with the goal of being simpler, quicker and more gentle to brain tissue than previous approaches. Under current clamp mode with a continuous train of hyperpolarizing current pulses, seal formation is initiated immediately upon cell contact, thus the "Touch". By maintaining the current injection, whole-cell access is spontaneously achieved within seconds from the cell-attached configuration by a self-limited membrane electroporation, or "Zap", as seal resistance increases. We present examples of intrinsic and visual responses of neurons and putative glial cells obtained with the revised method from cat and rat cortices in vivo. Recording parameters and biophysical properties obtained with the Touch and Zap method compare favourably with those obtained with the traditional blind patch approach, demonstrating that the revised approach does not compromise the recorded cell. We find that the method is particularly well-suited for whole-cell patch recordings of cortical glial cells in vivo, targeting a wider population of this cell type than the standard method, with better access resistance. Overall, the gentler Touch and Zap method is promising for studying quantitative functional properties in the intact brain with minimal perturbation of the cell's intrinsic properties and local network. Because the Touch and Zap method is performed semi-automatically, this approach is more reproducible and less dependent on experimenter technique.

The Touch and Zap Method for In Vivo Whole-Cell Patch Recording of Intrinsic and Visual Responses of Cortical Neurons and Glial Cells

PubMed Central

Schramm, Adrien E.; Marinazzo, Daniele; Gener, Thomas; Graham, Lyle J.

2014-01-01

Whole-cell patch recording is an essential tool for quantitatively establishing the biophysics of brain function, particularly in vivo. This method is of particular interest for studying the functional roles of cortical glial cells in the intact brain, which cannot be assessed with extracellular recordings. Nevertheless, a reasonable success rate remains a challenge because of stability, recording duration and electrical quality constraints, particularly for voltage clamp, dynamic clamp or conductance measurements. To address this, we describe “Touch and Zap”, an alternative method for whole-cell patch clamp recordings, with the goal of being simpler, quicker and more gentle to brain tissue than previous approaches. Under current clamp mode with a continuous train of hyperpolarizing current pulses, seal formation is initiated immediately upon cell contact, thus the “Touch”. By maintaining the current injection, whole-cell access is spontaneously achieved within seconds from the cell-attached configuration by a self-limited membrane electroporation, or “Zap”, as seal resistance increases. We present examples of intrinsic and visual responses of neurons and putative glial cells obtained with the revised method from cat and rat cortices in vivo. Recording parameters and biophysical properties obtained with the Touch and Zap method compare favourably with those obtained with the traditional blind patch approach, demonstrating that the revised approach does not compromise the recorded cell. We find that the method is particularly well-suited for whole-cell patch recordings of cortical glial cells in vivo, targeting a wider population of this cell type than the standard method, with better access resistance. Overall, the gentler Touch and Zap method is promising for studying quantitative functional properties in the intact brain with minimal perturbation of the cell's intrinsic properties and local network. Because the Touch and Zap method is performed semi-automatically, this approach is more reproducible and less dependent on experimenter technique. PMID:24875855

Learning-induced expression of meningeal ependymin mRNA and demonstration of ependymin in neurons and glial cells.

PubMed

Rother, S; Schmidt, R; Brysch, W; Schlingensiepen, K H

1995-10-01

The turnover of a CNS-specific cell adhesion glycoprotein, ependymin, has earlier been found to increase during periods of neuronal plasticity. Here, ependymin mRNA expression was analyzed by semiquantitative in situ hybridization in goldfish. Learning of an active avoidance response resulted in a significant increase in ependymin mRNA expression 20 min to 4 h after acquisition of the task. In contrast, yoked control animals that were exposed to the same numbers of conditioned and unconditioned stimuli in a random, unpaired manner exhibited a strong down-regulation of ependymin mRNA. Hybridization signals were also increased by injection of anti-ependymin antiserum into brain ventricles. Ependymin mRNA was exclusively localized to reticular-shaped fibroblasts of the inner endomeningeal cell layer. Immunoelectron microscopic investigation, however, revealed ependymin also in distinct neuronal and glial cell populations in which no ependymin mRNA had been detected. Uptake of meningeal protein factors into glial and neuronal cells may therefore be of functional importance for plastic adaptations of the CNS.

Intrathecal injection of fluorocitric acid inhibits the activation of glial cells causing reduced mirror pain in rats.

PubMed

Cao, Jing; Li, Zhihua; Zhang, Zhenhua; Ren, Xiuhua; Zhao, Qingzan; Shao, Jinping; Li, Ming; Wang, Jiannan; Huang, Puchao; Zang, Weidong

2014-01-01

Growing evidence has shown that unilateral nerve injury results in pain hypersensitivity in the ipsilateral and contralateral sides respective to the injury site. This phenomenon is known as mirror image pain (MIP). Glial cells have been indicated in the mechanism of MIP; however, it is not clear how glial cells are involved in MIP. To observe phenomenon MIP and the following mechanism, 20 adult male Sprague-Dawley rats (weighing 180-220 g) were separated into two groups: Sham Group (n = 10) and left L5 spinal nerve ligated and sectioned (SNL) group (n = 10). Thermal hyperalgesia and mechanical hypersensitivity were measured for both groups to determine if the SNL model had Mirror image of Pain (MIP). Nav1.7 protein expression in DRG was analyzed using immunohistochemistry and western-blotting. And then to observe the effect of fluorocitrate on MIP, 15 rats were separated into three Groups: Sham Group (n = 5); SNL + FC group: intrathecal injection of Fluorocitric acid(FC) 1 nmol/10 μL (n = 5); SNL + NS group: intrathecal injection of 0.9% Normal Saline (n = 5). Behavior testing, immunocytochemistry, and western-blotting using dorsal root ganglion (DRG) from both sides were then conducted. The results showed pain hypersensitivity in both hind-paws of the SNL animals, Mechanical tests showed the paw withdrawal threshold dropped from 13.30 ± 1.204 g to 2.57 ± 1.963 g at 14 d as will as the ipsilateral paw thermal withdrawal threshold dropped from 16.5 ± 2.236 s to 4.38 ± 2.544 s at 14 d. Mechanical tests showed the contralateral paw withdrawal threshold dropped from 14.01 ± 1.412 to 4.2 ± 1.789 g at 7d will the thermal withdrawal threshold dropped from 16.8 ± 2.176 s to 7.6 ± 1.517 s at 7d. Nav1.7 expression increased and glial cells actived in bilateral side DRG after SNL compared with sham group. After intrathecal injection of fluorocitrate, the glial cell in bilateral DRG were inhibited and the pain behavior were reversed in both hindpaws too. Fluorocitrate can inhibit the activation of glial cells in spinal cord and DRG, and reduce MIP.

Myricetin and quercetin attenuate ischemic injury in glial cultures by different mechanisms

USDA-ARS?s Scientific Manuscript database

We have demonstrated that polyphenols from cinnamon and green tea reduce cell swelling and mitochondrial dysfunction in C6 glial cultures following ischemic injury. We tested the protective effects of the flavonoid polyphenols, myricetin and quercetin, on key features of ischemic injury. C6 cultures...

Indoxyl Sulfate Affects Glial Function Increasing Oxidative Stress and Neuroinflammation in Chronic Kidney Disease: Interaction between Astrocytes and Microglia.

PubMed

Adesso, Simona; Magnus, Tim; Cuzzocrea, Salvatore; Campolo, Michela; Rissiek, Björn; Paciello, Orlando; Autore, Giuseppina; Pinto, Aldo; Marzocco, Stefania

2017-01-01

Indoxyl sulfate (IS) is a protein-bound uremic toxin resulting from the metabolism of dietary tryptophan which accumulates in patients with impaired renal function, such as chronic kidney disease (CKD). IS is a well-known nephrovascular toxin but little is known about its effects on central nervous system (CNS) cells. Considering the growing interest in the field of CNS comorbidities in CKD, we studied the effect of IS on CNS cells. IS (15-60 μM) treatment in C6 astrocyte cells increased reactive oxygen species release and decreased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activation, and heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone 1 expression. Moreover, IS increased Aryl hydrocarbon Receptor (AhR) and Nuclear Factor-kB (NF-kB) activation in these cells. Similiar observations were made in primary mouse astrocytes and mixed glial cells. Inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) expression, tumor necrosis factor-α and interleukin-6 release and nitrotyrosine formation were increased by IS (15-60 μM) in primary mouse astrocytes and mixed glial cells. IS increased AhR and NF-kB nuclear translocation and reduced Nrf2 translocation and HO-1 expression in primary glial cells. In addition, IS induced cell death in neurons in a dose dependent fashion. Injection of IS (800 mg/kg, i.p.) into mice induced histological changes and increased COX-2 expression and nitrotyrosine formation in thebrain tissue. Taken together, our results show a significant contribution of IS in generating a neurotoxic enviroment and it could also have a potential role in neurodegeneration. IS could be considered also a potential therapeutical target for CKD-associated neurodegenerative complications.

Gliotransmission and Brain Glucose Sensing

PubMed Central

Lanfray, Damien; Arthaud, Sébastien; Ouellet, Johanne; Compère, Vincent; Do Rego, Jean-Luc; Leprince, Jérôme; Lefranc, Benjamin; Castel, Hélène; Bouchard, Cynthia; Monge-Roffarello, Boris; Richard, Denis; Pelletier, Georges; Vaudry, Hubert; Tonon, Marie-Christine; Morin, Fabrice

2013-01-01

Hypothalamic glucose sensing is involved in the control of feeding behavior and peripheral glucose homeostasis, and glial cells are suggested to play an important role in this process. Diazepam-binding inhibitor (DBI) and its processing product the octadecaneuropeptide (ODN), collectively named endozepines, are secreted by astroglia, and ODN is a potent anorexigenic factor. Therefore, we investigated the involvement of endozepines in brain glucose sensing. First, we showed that intracerebroventricular administration of glucose in rats increases DBI expression in hypothalamic glial-like tanycytes. We then demonstrated that glucose stimulates endozepine secretion from hypothalamic explants. Feeding experiments indicate that the anorexigenic effect of central administration of glucose was blunted by coinjection of an ODN antagonist. Conversely, the hyperphagic response elicited by central glucoprivation was suppressed by an ODN agonist. The anorexigenic effects of centrally injected glucose or ODN agonist were suppressed by blockade of the melanocortin-3/4 receptors, suggesting that glucose sensing involves endozepinergic control of the melanocortin pathway. Finally, we found that brain endozepines modulate blood glucose levels, suggesting their involvement in a feedback loop controlling whole-body glucose homeostasis. Collectively, these data indicate that endozepines are a critical relay in brain glucose sensing and potentially new targets in treatment of metabolic disorders. PMID:23160530

Reductions in hypothalamic Gfap expression, glial cells and α-tanycytes in lean and hypermetabolic Gnasxl-deficient mice.

PubMed

Holmes, Andrew P; Wong, Shi Quan; Pulix, Michela; Johnson, Kirsty; Horton, Niamh S; Thomas, Patricia; de Magalhães, João Pedro; Plagge, Antonius

2016-04-14

Neuronal and glial differentiation in the murine hypothalamus is not complete at birth, but continues over the first two weeks postnatally. Nutritional status and Leptin deficiency can influence the maturation of neuronal projections and glial patterns, and hypothalamic gliosis occurs in mouse models of obesity. Gnasxl constitutes an alternative transcript of the genomically imprinted Gnas locus and encodes a variant of the signalling protein Gαs, termed XLαs, which is expressed in defined areas of the hypothalamus. Gnasxl-deficient mice show postnatal growth retardation and undernutrition, while surviving adults remain lean and hypermetabolic with increased sympathetic nervous system (SNS) activity. Effects of this knock-out on the hypothalamic neural network have not yet been investigated. RNAseq analysis for gene expression changes in hypothalami of Gnasxl-deficient mice indicated Glial fibrillary acid protein (Gfap) expression to be significantly down-regulated in adult samples. Histological analysis confirmed a reduction in Gfap-positive glial cell numbers specifically in the hypothalamus. This reduction was observed in adult tissue samples, whereas no difference was found in hypothalami of postnatal stages, indicating an adaptation in adult Gnasxl-deficient mice to their earlier growth phenotype and hypermetabolism. Especially noticeable was a loss of many Gfap-positive α-tanycytes and their processes, which form part of the ependymal layer that lines the medial and dorsal regions of the 3(rd) ventricle, while β-tanycytes along the median eminence (ME) and infundibular recesses appeared unaffected. This was accompanied by local reductions in Vimentin and Nestin expression. Hypothalamic RNA levels of glial solute transporters were unchanged, indicating a potential compensatory up-regulation in the remaining astrocytes and tanycytes. Gnasxl deficiency does not directly affect glial development in the hypothalamus, since it is expressed in neurons, and Gfap-positive astrocytes and tanycytes appear normal during early postnatal stages. The loss of Gfap-expressing cells in adult hypothalami appears to be a consequence of the postnatal undernutrition, hypoglycaemia and continued hypermetabolism and leanness of Gnasxl-deficient mice, which contrasts with gliosis observed in obese mouse models. Since α-tanycytes also function as adult neural progenitor cells, these findings might indicate further developmental abnormalities in hypothalamic formations of Gnasxl-deficient mice, potentially including neuronal composition and projections.

A Lifetime's Adventure in Extracellular K+ Regulation: The Scottish Connection.

PubMed

Brown, Angus M

2017-09-01

In a career that has spanned 45 years and shows no signs of slowing down, Dr Bruce Ransom has devoted considerable time and energy to studying regulation of interstitial K + . When Bruce commenced his studies in 1969 virtually nothing was known of the functions of glial cells, but Bruce's research contributed to the physiological assignation of function to mammalian astrocytes, namely interstitial K + buffering. The experiments that I describe in this review concern the response of the membrane potential (Em) of in vivo cat cortical astrocytes to changes in [K + ] o , an experimental manoeuvre that was achieved in two different ways. The first involved recording the Em of an astrocyte while the initial aCSF was switched to one with different K + , whereas in the second series of experiments the cortex was stimulated and the response of the astrocyte Em to the K + released from neighbouring neurons was recorded. The astrocytes responded in a qualitatively predictable manner, but quantitatively the changes were not as predicted by the Nernst equation. Elevations in interstitial K + are not sustained and K + returns to baseline rapidly due to the buffering capacity of astrocytes, a phenomenon studied by Bruce, and his son Chris, published 27 years after Bruce's initial publications. Thus, a lifetime spent investigating K + buffering has seen enormous advances in glial research, from the time cells were identified as 'presumed' glial cells or 'silent cells', to the present day, where glial cells are recognised as contributing to every important physiological brain function.

The Proteome of Native Adult Müller Glial Cells From Murine Retina*

PubMed Central

Hauser, Alexandra; Lepper, Marlen Franziska; Mayo, Rebecca

2016-01-01

To date, the proteomic profiling of Müller cells, the dominant macroglia of the retina, has been hampered because of the absence of suitable enrichment methods. We established a novel protocol to isolate native, intact Müller cells from adult murine retinae at excellent purity which retain in situ morphology and are well suited for proteomic analyses. Two different strategies of sample preparation - an in StageTips (iST) and a subcellular fractionation approach including cell surface protein profiling were used for quantitative liquid chromatography-mass spectrometry (LC-MSMS) comparing Müller cell-enriched to depleted neuronal fractions. Pathway enrichment analyses on both data sets enabled us to identify Müller cell-specific functions which included focal adhesion kinase signaling, signal transduction mediated by calcium as second messenger, transmembrane neurotransmitter transport and antioxidant activity. Pathways associated with RNA processing, cellular respiration and phototransduction were enriched in the neuronal subpopulation. Proteomic results were validated for selected Müller cell genes by quantitative real time PCR, confirming the high expression levels of numerous members of the angiogenic and anti-inflammatory annexins and antioxidant enzymes (e.g. paraoxonase 2, peroxiredoxin 1, 4 and 6). Finally, the significant enrichment of antioxidant proteins in Müller cells was confirmed by measurements on vital retinal cells using the oxidative stress indicator CM-H2DCFDA. In contrast to photoreceptors or bipolar cells, Müller cells were most efficiently protected against H2O2-induced reactive oxygen species formation, which is in line with the protein repertoire identified in the proteomic profiling. Our novel approach to isolate intact glial cells from adult retina in combination with proteomic profiling enabled the identification of novel Müller glia specific proteins, which were validated as markers and for their functional impact in glial physiology. This provides the basis to allow the discovery of novel glial specializations and will enable us to elucidate the role of Müller cells in retinal pathologies — a topic still controversially discussed. PMID:26324419

Transmitter-induced glycogenolysis and gluconeogenesis in leech segmental ganglia.

PubMed

Pennington, A J; Pentreath, V W

1987-01-01

1. The utilization and control of glycogen stores were studied in the isolated segmental ganglia of the horse leech, Haemopis sanguisuga. The glycogen in the ganglia was extracted and assayed fluorimetrically and its cellular localization and turnover studied by autoradiography in conjunction with [3H] glucose. 2. The glycogen levels were measured after incubation with different neurotransmitters for 60 min at 28 degrees C. The results for each experimental ganglion were compared to a paired control ganglion, and the results analysed by paired t-tests. 3. Several transmitter substances (5-HT, octopamine, dopamine, noradrenaline, histamine) produced reductions in glycogen (glycogenolysis); other transmitters (glutamate, GABA) produced increases in glycogen (gluconeogenesis); others (adenosine, glycine) produced reductions or increases, depending on concentration. Acetylcholine had no effect on the glycogen levels. 4. Most of the glycogen in the ganglia is localized in the packet glial cells, which surround the neuron perikarya. Autoradiographic analysis demonstrated that the effects of histamine and dopamine were principally on the glycogen in the glial cells. 5. Adenylate cyclase was demonstrated by electron microscope histochemistry to be localized on the plasma membranes of the glial cells, and to a lesser extent on the neuronal membranes. 6. It is concluded that the changes in glycogen in the glial cells may be party controlled by transmitters via adenylate cyclase. This may provide a sensitive mechanism for coupling neuronal activity with energy metabolism.

Ammonia impairs glutamatergic communication in astroglial cells: protective role of resveratrol.

PubMed

Bobermin, Larissa Daniele; Hansel, Gisele; Scherer, Emilene B S; Wyse, Angela T S; Souza, Diogo Onofre; Quincozes-Santos, André; Gonçalves, Carlos-Alberto

2015-12-01

Ammonia is a key toxin in the precipitation of hepatic encephalopathy (HE), a neuropsychiatric disorder associated with liver failure. In response to ammonia, various toxic events are triggered in astroglial cells, and alterations in brain glutamate communication are common. Resveratrol is a polyphenolic compound that has been extensively studied in pathological events because it presents several beneficial effects, including some in the central nervous system (CNS). We previously described that resveratrol is able to significantly modulate glial functioning and has a protective effect during ammonia challenge in vitro. In this study, we addressed the mechanisms by which resveratrol can protect C6 astroglial cells from glutamatergic alterations induced by ammonia. Resveratrol was able to prevent all the effects triggered by ammonia: (i) decrease in glutamate uptake activity and expression of the EAAC1 glutamate transporter, the main glutamate transporter present in C6 cells; (ii) increase of glutamate release, which was also dependent on the activation of the Na(+)-K(+)-Cl(-) co-transporter NKCC1; (iii) reduction in GS activity and intracellular GSH content; and (iv) impairment of Na(+)K(+)-ATPase activity. Interestingly, resveratrol, per se, also positively modulated the astroglial functions evaluated. Moreover, we demonstrated that heme oxygenase 1 (HO1), an enzyme that is part of the cellular defense system, mediated some of the effects of resveratrol. In conclusion, the mechanisms of the putative protective role of resveratrol against ammonia toxicity involve the modulation of pathways and molecules related to glutamate communication in astroglial cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Reciprocal interactions between neurons and glia are required for Drosophila peripheral nervous system development.

PubMed

Sepp, Katharine J; Auld, Vanessa J

2003-09-10

A major developmental role of peripheral glia is to mediate sensory axon guidance; however, it is not known whether sensory neurons influence peripheral glial development. To determine whether glia and neurons reciprocally interact during embryonic development, we ablated each cell type by overexpressing the apoptosis gene, grim, and observed the effects on peripheral nervous system (PNS) development. When neurons are ablated, glial defects occur as a secondary effect, and vice versa. Therefore glia and neurons are codependent during embryogenesis. To further explore glial-neuronal interactions, we genetically disrupted glial migration or differentiation and observed the secondary effects on sensory neuron development. Glial migration and ensheathment of PNS axons was blocked by overexpression of activated Rho GTPase, a regulator of actin dynamics. Here, sensory axons extended to the CNS without exhibiting gross pathfinding errors. In contrast, disrupting differentiation by expression of dominant-negative Ras GTPase in glia resulted in major sensory axon pathfinding errors, similar to those seen in glial ablations. Glial overexpression of transgenic components of the epidermal growth factor receptor (EGFR) signaling pathway yielded similar sensory neuron defects and also downregulated the expression of the glial marker Neuroglian. Mutant analysis also suggested that the EGFR ligands Spitz and Vein play roles in peripheral glial development. The observations support a model in which glia express genes necessary for sensory neuron development, and these genes are potentially under the control of the EGFR/Ras signaling pathway.

Use of a heterologous monoclonal antibody for cloning and detection of glial fibrillary acidic protein in the bovine ventricular ependyma.

PubMed

Bouchard, P; Ravet, V; Meiniel, R; Creveaux, I; Meiniel, A; Vellet, A; Vigues, B

1999-11-01

From protozoans to vertebrates, ciliated cells are characterized by well-developed cytoskeletal structures. An outstanding example is the epiplasm, a thick, submembranous skeleton that serves to anchor basal bodies and other cell surface-related organelles in ciliated protozoans. An epiplasm-like cytoskeleton has not yet been observed in metazoan ciliated cells. In a previous study, we reported on MAb E501, a monoclonal antibody raised against epiplasmin-C, the major membrane skeletal protein in the ciliate Tetrahymena pyriformis. It was shown that MAb E501 cross-reacts with glial fibrillary acidic protein (GFAP), the class III intermediate filament protein found in astrocytes and other related glial elements. Here we used a post-embedding immunogold-staining method to localize MAb E501 cross-reactive antigens in ciliated cells from the ventricular ependyma in bovine embryos. When ependymocytes were treated with MAb E501, the ciliated region of the cell cortex was devoid of significant labeling. Instead, a gold particle deposit was evident around the nucleus, with only conventional ependymocytes being immunostained. Similar results were obtained by utilizing a rabbit antiserum against GFAP, revealing glial filaments and indicating an astroglial lineage of conventional bovine ependymocytes. In contrast, secretory ependymocytes of the subcommissural organ (SCO) were not stained by either of the two antibodies. Using MAb E501 as a heterologous probe, we cloned bovine GFAP cDNA. In situ hybridization experiments failed to detect GFAP transcripts in SCO ependymocytes, confirming the abscence of immunoreactivity in these cells.

Diverse Neurotoxicants Target the Differentiation of Embryonic Neural Stem Cells into Neuronal and Glial Phenotypes

PubMed Central

Slotkin, Theodore A.; Skavicus, Samantha; Card, Jennifer; Levin, Edward D.; Seidler, Frederic J.

2016-01-01

The large number of compounds that need to be tested for developmental neurotoxicity drives the need to establish in vitro models to evaluate specific neurotoxic endpoints. We used neural stem cells derived from rat neuroepithelium on embryonic day 14 to evaluate the impact of diverse toxicants on their ability to differentiate into glia and neurons: a glucocorticoid (dexamethasone), organophosphate insecticides (chlorpyrifos, diazinon, parathion), insecticides targeting the GABAA receptor (dieldrin, fipronil), heavy metals (Ni2+, Ag+), nicotine and tobacco smoke extract. We found three broad groupings of effects. One diverse set of compounds, dexamethasone, the organophosphate pesticides, Ni2+ and nicotine, suppressed expression of the glial phenotype while having little or no effect on the neuronal phenotype. The second pattern was restricted to the pesticides acting on GABAA receptors. These compounds promoted the glial phenotype and suppressed the neuronal phenotype. Notably, the actions of compounds eliciting either of these differentiation patterns were clearly unrelated to deficits in cell numbers: dexamethasone, dieldrin and fipronil all reduced cell numbers, whereas organophosphates and Ni2+ had no effect. The third pattern, shared by Ag+ and tobacco smoke extract, clearly delineated cytotoxicity, characterized major cell loss with suppression of differentiation into both glial and neuronal phenotypes; but here again, there was some selectivity in that glia were suppressed more than neurons. Our results, from this survey with diverse compounds, point to convergence of neurotoxicant effects on a specific “decision node” that controls the emergence of neurons and glia from neural stem cells. PMID:27816694

Injury-activated glial cells promote wound healing of the adult skin in mice.

PubMed

Parfejevs, Vadims; Debbache, Julien; Shakhova, Olga; Schaefer, Simon M; Glausch, Mareen; Wegner, Michael; Suter, Ueli; Riekstina, Una; Werner, Sabine; Sommer, Lukas

2018-01-16

Cutaneous wound healing is a complex process that aims to re-establish the original structure of the skin and its functions. Among other disorders, peripheral neuropathies are known to severely impair wound healing capabilities of the skin, revealing the importance of skin innervation for proper repair. Here, we report that peripheral glia are crucially involved in this process. Using a mouse model of wound healing, combined with in vivo fate mapping, we show that injury activates peripheral glia by promoting de-differentiation, cell-cycle re-entry and dissemination of the cells into the wound bed. Moreover, injury-activated glia upregulate the expression of many secreted factors previously associated with wound healing and promote myofibroblast differentiation by paracrine modulation of TGF-β signalling. Accordingly, depletion of these cells impairs epithelial proliferation and wound closure through contraction, while their expansion promotes myofibroblast formation. Thus, injury-activated glia and/or their secretome might have therapeutic potential in human wound healing disorders.

The CXCL16-CXCR6 chemokine axis in glial tumors.

PubMed

Hattermann, Kirsten; Held-Feindt, Janka; Ludwig, Andreas; Mentlein, Rolf

2013-07-15

Since chemokines and their receptors play a pivotal role in tumors, we investigated the CXCL16-CXCR6-axis in human astroglial tumors. The transmembrane chemokine CXCL16 is heavily expressed by tumor, microglial and endothelial cells in situ and in vitro. In contrast, the receptor CXCR6 is restricted in glioblastomas to a small subset of proliferating cells positive for the stem-cell markers Musashi, Nanog, Sox2 and Oct4. In particular, the vast majority (about 90%) of Musashi-positive cells stained also for CXCR6. Thus, CXCL16 is highly expressed by glial tumor and stroma cells whereas CXCR6 defines a subset of cells with stem cell character. Copyright © 2013 Elsevier B.V. All rights reserved.

Sulfatase-mediated manipulation of the astrocyte-Schwann cell interface.

PubMed

O'Neill, Paul; Lindsay, Susan L; Pantiru, Andreea; Guimond, Scott E; Fagoe, Nitish; Verhaagen, Joost; Turnbull, Jeremy E; Riddell, John S; Barnett, Susan C

2017-01-01

Schwann cell (SC) transplantation following spinal cord injury (SCI) may have therapeutic potential. Functional recovery is limited however, due to poor SC interactions with host astrocytes and the induction of astrogliosis. Olfactory ensheathing cells (OECs) are closely related to SCs, but intermix more readily with astrocytes in culture and induce less astrogliosis. We previously demonstrated that OECs express higher levels of sulfatases, enzymes that remove 6-O-sulfate groups from heparan sulphate proteoglycans, than SCs and that RNAi knockdown of sulfatase prevented OEC-astrocyte mixing in vitro. As human OECs are difficult to culture in large numbers we have genetically engineered SCs using lentiviral vectors to express sulfatase 1 and 2 (SC-S1S2) and assessed their ability to interact with astrocytes. We demonstrate that SC-S1S2s have increased integrin-dependent motility in the presence of astrocytes via modulation of NRG and FGF receptor-linked PI3K/AKT intracellular signaling and do not form boundaries with astrocytes in culture. SC-astrocyte mixing is dependent on local NRG concentration and we propose that sulfatase enzymes influence the bioavailability of NRG ligand and thus influence SC behavior. We further demonstrate that injection of sulfatase expressing SCs into spinal cord white matter results in less glial reactivity than control SC injections comparable to that of OEC injections. Our data indicate that sulfatase-mediated modification of the extracellular matrix can influence glial interactions with astrocytes, and that SCs engineered to express sulfatase may be more OEC-like in character. This approach may be beneficial for cell transplant-mediated spinal cord repair. GLIA 2016 GLIA 2017;65:19-33. © 2016 The Authors. Glia Published by Wiley Periodicals, Inc.

The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology.

PubMed

Murk, Kai; Blanco Suarez, Elena M; Cockbill, Louisa M R; Banks, Paul; Hanley, Jonathan G

2013-09-01

Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult.

Anti-Obesity Sodium Tungstate Treatment Triggers Axonal and Glial Plasticity in Hypothalamic Feeding Centers

PubMed Central

Amigó-Correig, Marta; Barceló-Batllori, Sílvia; Soria, Guadalupe; Krezymon, Alice; Benani, Alexandre; Pénicaud, Luc; Tudela, Raúl; Planas, Anna Maria; Fernández, Eduardo

2012-01-01

Objective This study aims at exploring the effects of sodium tungstate treatment on hypothalamic plasticity, which is known to have an important role in the control of energy metabolism. Methods Adult lean and high-fat diet-induced obese mice were orally treated with sodium tungstate. Arcuate and paraventricular nuclei and lateral hypothalamus were separated and subjected to proteomic analysis by DIGE and mass spectrometry. Immunohistochemistry and in vivo magnetic resonance imaging were also performed. Results Sodium tungstate treatment reduced body weight gain, food intake, and blood glucose and triglyceride levels. These effects were associated with transcriptional and functional changes in the hypothalamus. Proteomic analysis revealed that sodium tungstate modified the expression levels of proteins involved in cell morphology, axonal growth, and tissue remodeling, such as actin, CRMP2 and neurofilaments, and of proteins related to energy metabolism. Moreover, immunohistochemistry studies confirmed results for some targets and further revealed tungstate-dependent regulation of SNAP25 and HPC-1 proteins, suggesting an effect on synaptogenesis as well. Functional test for cell activity based on c-fos-positive cell counting also suggested that sodium tungstate modified hypothalamic basal activity. Finally, in vivo magnetic resonance imaging showed that tungstate treatment can affect neuronal organization in the hypothalamus. Conclusions Altogether, these results suggest that sodium tungstate regulates proteins involved in axonal and glial plasticity. The fact that sodium tungstate could modulate hypothalamic plasticity and networks in adulthood makes it a possible and interesting therapeutic strategy not only for obesity management, but also for other neurodegenerative illnesses like Alzheimer’s disease. PMID:22802935

A glial palisade delineates the ipsilateral optic projection in Monodelphis.

PubMed

MacLaren, R E

1998-01-01

In developing marsupials, the path taken through the optic chiasm by ipsilaterally projecting retinal ganglion cells is complicated. Just prior to entry into the chiasm, ganglion cells destined for the ipsilateral optic tract separate from the remainder of axons by turning abruptly downwards to take a position in the ventral part of the optic nerve. In this report, it is shown that a discrete population of about 10-15 large glial cells transiently form a linear array across the prechiasmatic part of the optic nerve, precisely at this axon turning point. The distinct morphology of these cells and their novel location may reflect a specialized role in axon guidance.

Desmoplastic ganglioglioma of the spinal cord in a western European hedgehog (Erinaceus europaeus).

PubMed

Ulrich, Reiner; Stan, Alexandru C; Fehr, Michael; Mallig, Carolin; Puff, Christina

2010-11-01

Gangliogliomas are composed of neoplastic glial and neuronal cells and are extremely rare tumors of the central nervous system of domestic animals. The present report describes the clinical presentation and the pathomorphological and immunophenotypical characteristics of a desmoplastic ganglioglioma in the spinal cord of a 3-year-old male western European hedgehog (Erinaceus europaeus). Clinically, the hedgehog exhibited a skin wound and therapy-resistant paresis of the left hind limb. Necropsy showed dilatation of the urinary bladder. Histologic examination of the thoracic spinal cord revealed a focally extensive infiltrative mass, which consisted of multiple nodules of smaller bipolar or oligopolar glial cells and variably sized polygonal, ganglionic, neuron-like cells embedded in variable amounts of microcystic neuropilic matrix. An area of spindle-shaped cells arranged in interwoven fascicles and surrounded by a prominent network of reticulin fibers was interpreted as desmoplastic leptomeningeal stroma. Immunohistochemistry revealed a moderate number of glial fibrillary acidic protein and S-100-positive cells and processes. In addition, the ganglionic neuron-like cells expressed neurofilament, microtubule-associated protein-2, and neuron-specific enolase. In summary, this spinal cord tumor was composed of astroglial and neuronal cellular elements, justifying the diagnosis of a desmoplastic ganglioglioma.

Glucose Transporter 1 and Monocarboxylate Transporters 1, 2, and 4 Localization within the Glial Cells of Shark Blood-Brain-Barriers

PubMed Central

Balmaceda-Aguilera, Carolina; Cortés-Campos, Christian; Cifuentes, Manuel; Peruzzo, Bruno; Mack, Lauren; Tapia, Juan Carlos; Oyarce, Karina; García, María Angeles; Nualart, Francisco

2012-01-01

Although previous studies showed that glucose is used to support the metabolic activity of the cartilaginous fish brain, the distribution and expression levels of glucose transporter (GLUT) isoforms remained undetermined. Optic/ultrastructural immunohistochemistry approaches were used to determine the expression of GLUT1 in the glial blood-brain barrier (gBBB). GLUT1 was observed solely in glial cells; it was primarily located in end-feet processes of the gBBB. Western blot analysis showed a protein with a molecular mass of 50 kDa, and partial sequencing confirmed GLUT1 identity. Similar approaches were used to demonstrate increased GLUT1 polarization to both apical and basolateral membranes in choroid plexus epithelial cells. To explore monocarboxylate transporter (MCT) involvement in shark brain metabolism, the expression of MCTs was analyzed. MCT1, 2 and 4 were expressed in endothelial cells; however, only MCT1 and MCT4 were present in glial cells. In neurons, MCT2 was localized at the cell membrane whereas MCT1 was detected within mitochondria. Previous studies demonstrated that hypoxia modified GLUT and MCT expression in mammalian brain cells, which was mediated by the transcription factor, hypoxia inducible factor-1. Similarly, we observed that hypoxia modified MCT1 cellular distribution and MCT4 expression in shark telencephalic area and brain stem, confirming the role of these transporters in hypoxia adaptation. Finally, using three-dimensional ultrastructural microscopy, the interaction between glial end-feet and leaky blood vessels of shark brain was assessed in the present study. These data suggested that the brains of shark may take up glucose from blood using a different mechanism than that used by mammalian brains, which may induce astrocyte-neuron lactate shuttling and metabolic coupling as observed in mammalian brain. Our data suggested that the structural conditions and expression patterns of GLUT1, MCT1, MCT2 and MCT4 in shark brain may establish the molecular foundation of metabolic coupling between glia and neurons. PMID:22389700

Cytokine-induced activation of glial cells in the mouse brain is enhanced at an advanced age.

PubMed

Deng, X-H; Bertini, G; Xu, Y-Z; Yan, Z; Bentivoglio, M

2006-08-25

Numerous neurological diseases which include neuroinflammatory components exhibit an age-related prevalence. The aging process is characterized by an increase of inflammatory mediators both systemically and in the brain, which may prime glial cells. However, little information is available on age-related changes in the glial response of the healthy aging brain to an inflammatory challenge. This problem was here examined using a mixture of the proinflammatory cytokines interferon-gamma and tumor necrosis factor-alpha, which was injected intracerebroventricularly in young (2-3.5 months), middle-aged (10-11 months) and aged (18-21 months) mice. Vehicle (phosphate-buffered saline) was used as control. After a survival of 1 or 2 days (all age groups) or 4 days (young and middle-aged animals), immunohistochemically labeled astrocytes and microglia were investigated both qualitatively and quantitatively. In all age groups, astrocytes were markedly activated in periventricular as well as in deeper brain regions 2 days following cytokine treatment, whereas microglia activation was already evident at 24 h. Interestingly, cytokine-induced activation of both astrocytes and microglia was significantly more marked in the brain of aged animals, in which it included numerous ameboid microglia, than of younger age groups. Moderate astrocytic activation was also seen in the hippocampal CA1 field of vehicle-treated aged mice. FluoroJade B histochemistry and the terminal deoxynucleotidyl transferase-mediated UTP nick-end labeling technique, performed at 2 days after cytokine administration, did not reveal ongoing cell death phenomena in young or aged animals. This indicated that glial cell changes were not secondary to neuronal death. Altogether, the findings demonstrate for the first time enhanced activation of glial cells in the old brain, compared with young and middle-aged subjects, in response to cytokine exposure. Interestingly, the results also suggest that such enhancement does not develop gradually since youth, but appears characterized by relatively late onset.

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

PubMed

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

2016-11-01

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

pH modulation of glial glutamate transporters regulates synaptic transmission in the nucleus of the solitary tract

PubMed Central

McCrimmon, Donald R.; Martina, Marco

2013-01-01

The nucleus of the solitary tract (NTS) is the major site for termination of visceral sensory afferents contributing to homeostatic regulation of, for example, arterial pressure, gastric motility, and breathing. Whereas much is known about how different neuronal populations influence these functions, information about the role of glia remains scant. In this article, we propose that glia may contribute to NTS functions by modulating excitatory neurotransmission. We found that acidification (pH 7.0) depolarizes NTS glia by inhibiting K+-selective membrane currents. NTS glia also showed functional expression of voltage-sensitive glutamate transporters, suggesting that extracellular acidification regulates synaptic transmission by compromising glial glutamate uptake. To test this hypothesis, we evoked glutamatergic slow excitatory potentials (SEPs) in NTS neurons with repetitive stimulation (20 pulses at 10 Hz) of the solitary tract. This SEP depends on accumulation of glutamate following repetitive stimulation, since it was potentiated by blocking glutamate uptake with dl-threo-β-benzyloxyaspartic acid (TBOA) or a glia-specific glutamate transport blocker, dihydrokainate (DHK). Importantly, extracellular acidification (pH 7.0) also potentiated the SEP. This effect appeared to be mediated through a depolarization-induced inhibition of glial transporter activity, because it was occluded by TBOA and DHK. In agreement, pH 7.0 did not directly alter d-aspartate-induced responses in NTS glia or properties of presynaptic glutamate release. Thus acidification-dependent regulation of glial function affects synaptic transmission within the NTS. These results suggest that glia play a modulatory role in the NTS by integrating local tissue signals (such as pH) with synaptic inputs from peripheral afferents. PMID:23615553

Tramadol and propentofylline coadministration exerted synergistic effects on rat spinal nerve ligation-induced neuropathic pain.

PubMed

Zhang, Jin; Wu, Dan; Xie, Cheng; Wang, Huan; Wang, Wei; Zhang, Hui; Liu, Rui; Xu, Li-Xian; Mei, Xiao-Peng

2013-01-01

Neuropathic pain is an intractable clinical problem. Drug treatments such as tramadol have been reported to effectively decrease neuropathic pain by inhibiting the activity of nociceptive neurons. It has also been reported that modulating glial activation could also prevent or reverse neuropathic pain via the administration of a glial modulator or inhibitor, such as propentofylline. Thus far, there has been no clinical strategy incorporating both neuronal and glial participation for treating neuropathic pain. Therefore, the present research study was designed to assess whether coadministration of tramadol and propentofylline, as neuronal and glial activation inhibitors, respectively, would exert a synergistic effect on the reduction of rat spinal nerve ligation (SNL)-induced neuropathic pain. Rats underwent SNL surgery to induce neuropathic pain. Pain behavioral tests were conducted to ascertain the effect of drugs on SNL-induced mechanical allodynia with von-Frey hairs. Proinflammatory factor interleukin-1β (IL-1β) expression was also detected by Real-time RT-PCR. Intrathecal tramadol and propentofylline administered alone relieved SNL-induced mechanical allodynia in a dose-dependent manner. Tramadol and propentofylline coadministration exerted a more potent effect in a synergistic and dose dependent manner than the intrathecal administration of either drug alone. Real-time RT-PCR demonstrated IL-1β up-expression in the ipsilateral spinal dorsal horn after the lesion, which was significantly decreased by tramadol and propentofylline coadministration. Inhibiting proinflammatory factor IL-1β contributed to the synergistic effects of tramadol and propentofylline coadministration on rat peripheral nerve injury-induced neuropathic pain. Thus, our study provided a rationale for utilizing a novel strategy for treating neuropathic pain by blocking the proinflammatory factor related pathways in the central nervous system.

Tramadol and Propentofylline Coadministration Exerted Synergistic Effects on Rat Spinal Nerve Ligation-Induced Neuropathic Pain

PubMed Central

Wang, Huan; Wang, Wei; Zhang, Hui; Liu, Rui; Xu, Li-Xian; Mei, Xiao-Peng

2013-01-01

Neuropathic pain is an intractable clinical problem. Drug treatments such as tramadol have been reported to effectively decrease neuropathic pain by inhibiting the activity of nociceptive neurons. It has also been reported that modulating glial activation could also prevent or reverse neuropathic pain via the administration of a glial modulator or inhibitor, such as propentofylline. Thus far, there has been no clinical strategy incorporating both neuronal and glial participation for treating neuropathic pain. Therefore, the present research study was designed to assess whether coadministration of tramadol and propentofylline, as neuronal and glial activation inhibitors, respectively, would exert a synergistic effect on the reduction of rat spinal nerve ligation (SNL)-induced neuropathic pain. Rats underwent SNL surgery to induce neuropathic pain. Pain behavioral tests were conducted to ascertain the effect of drugs on SNL-induced mechanical allodynia with von-Frey hairs. Proinflammatory factor interleukin-1β (IL-1β) expression was also detected by Real-time RT-PCR. Intrathecal tramadol and propentofylline administered alone relieved SNL-induced mechanical allodynia in a dose-dependent manner. Tramadol and propentofylline coadministration exerted a more potent effect in a synergistic and dose dependent manner than the intrathecal administration of either drug alone. Real-time RT-PCR demonstrated IL-1β up-expression in the ipsilateral spinal dorsal horn after the lesion, which was significantly decreased by tramadol and propentofylline coadministration. Inhibiting proinflammatory factor IL-1β contributed to the synergistic effects of tramadol and propentofylline coadministration on rat peripheral nerve injury-induced neuropathic pain. Thus, our study provided a rationale for utilizing a novel strategy for treating neuropathic pain by blocking the proinflammatory factor related pathways in the central nervous system. PMID:24009718

The migrational patterns and developmental fates of glial precursors in the rat subventricular zone are temporally regulated.

PubMed

Levison, S W; Chuang, C; Abramson, B J; Goldman, J E

1993-11-01

Postnatal gliogenesis in the rodent forebrain was studied by infecting subventricular zone cells of either neonates or juvenile rats with replication-deficient retroviruses that encode reporter enzymes, enabling the migration and fate of these germinal zone cells to be traced over the ensuing several weeks. Neither neonatal nor juvenile subventricular zone cells migrated substantially along the rostral-caudal axis. Neonatal subventricular zone cells migrated dorsally and laterally into hemispheric gray and white matter and became both astrocytes and oligodendrocytes. Juvenile subventricular zone cells migrated into more medial areas of the subcortical white matter and on occasion appeared in the white matter of the contralateral hemisphere, but rarely migrated into the neocortex. Juvenile subventricular zone cells almost exclusively differentiated into oligodendrocytes. Thus, the migratory patterns and the developmental fates of subventricular zone cells change during the first 2 weeks of life. When either neonatal or juvenile subventricular zone cells were labeled in vivo and then removed and cultured, some generated homogeneous clones that contained either astrocytes with a 'type 1' phenotype or oligodendrocytes, but some generated heterogeneous clones that contained both glial types. These results provide additional evidence for a common progenitor for astrocytes and oligodendrocytes and strongly suggest that temporally and spatially regulated environmental signals control the destiny of glial progenitors during postnatal development.

Lentiviral-mediated Targeted NF-κB Blockade in Dorsal Spinal Cord Glia Attenuates Sciatic Nerve Injury-induced Neuropathic Pain in the Rat.

PubMed

Meunier, Alice; Latrémolière, Alban; Dominguez, Elisa; Mauborgne, Annie; Philippe, Stéphanie; Hamon, Michel; Mallet, Jacques; Benoliel, Jean-Jacques; Pohl, Michel

2007-04-01

Neuropathic pain developing after peripheral nerve injury is associated with altered neuronal and glial cell functions in the spinal cord. Activated glia produces algogenic mediators, exacerbating pain. Among the different intracellular pathways possibly involved in the modified glial function, the nuclear factor κB (NF-κB) system is of particular interest, as numerous genes encoding inflammation- and pain-related molecules are controlled by this transcription factor. NF-κB is a pleiotropic factor also involved in central nervous system homeostasy. To study its role in chronic pain, it is thus essential to inhibit the NF-κB pathway selectively in activated spinal glial cells. Here, we show that when restricted to spinal cord and targeted to glial cells, lentiviral vector-mediated delivery of NF-κB super- repressor IκBα resulted in an inhibition of the NF-κB pathway activated in the rat spinal cord after sciatic nerve injury (chronic constriction injury, CCI). Concomitantly, IκBα overproduction prevented the enhanced expression of interleukin-6 and of inducible nitric oxide synthase associated with chronic constriction injury and resulted in prolonged antihyperalgesic and antiallodynic effects. These data show that targeted blockade of NF-κB activity in spinal glia efficiently alleviates pain behavior in CCI rats, demonstrating the active participation of the glial NF-κB pathway in the development of neuropathic pain after peripheral nerve injury. Copyright © 2007 The American Society of Gene Therapy. Published by Elsevier Inc. All rights reserved.

Glial cell morphological and density changes through the lifespan of rhesus macaques.

PubMed

Robillard, Katelyn N; Lee, Kim M; Chiu, Kevin B; MacLean, Andrew G

2016-07-01

How aging impacts the central nervous system (CNS) is an area of intense interest. Glial morphology is known to affect neuronal and immune function as well as metabolic and homeostatic balance. Activation of glia, both astrocytes and microglia, occurs at several stages during development and aging. The present study analyzed changes in glial morphology and density through the entire lifespan of rhesus macaques, which are physiologically and anatomically similar to humans. We observed apparent increases in gray matter astrocytic process length and process complexity as rhesus macaques matured from juveniles through adulthood. These changes were not attributed to cell enlargement because they were not accompanied by proportional changes in soma or process volume. There was a decrease in white matter microglial process length as rhesus macaques aged. Aging was shown to have a significant effect on gray matter microglial density, with a significant increase in aged macaques compared with adults. Overall, we observed significant changes in glial morphology as macaques age indicative of astrocytic activation with subsequent increase in microglial density in aged macaques. Copyright © 2016 Elsevier Inc. All rights reserved.

History of Glial Cell Line-Derived Neurotrophic Factor (GDNF) and Its Use for Spinal Cord Injury Repair.

PubMed

Walker, Melissa J; Xu, Xiao-Ming

2018-06-13

Following an initial mechanical insult, traumatic spinal cord injury (SCI) induces a secondary wave of injury, resulting in a toxic lesion environment inhibitory to axonal regeneration. This review focuses on the glial cell line-derived neurotrophic factor (GDNF) and its application, in combination with other factors and cell transplantations, for repairing the injured spinal cord. As studies of recent decades strongly suggest that combinational treatment approaches hold the greatest therapeutic potential for the central nervous system (CNS) trauma, future directions of combinational therapies will also be discussed.

Orphan nuclear receptor TLX regulates astrogenesis by modulating BMP signaling

PubMed Central

Qin, Song; Niu, Wenze; Iqbal, Nida; Smith, Derek K.; Zhang, Chun-Li

2014-01-01

Neural stem cells (NSCs) are self-renewing multipotent progenitors that generate both neurons and glia. The precise control of NSC behavior is fundamental to the architecture and function of the central nervous system. We previously demonstrated that the orphan nuclear receptor TLX is required for postnatal NSC activation and neurogenesis in the neurogenic niche. Here, we show that TLX modulates bone morphogenetic protein (BMP)-SMAD signaling to control the timing of postnatal astrogenesis. Genes involved in the BMP signaling pathway, such as Bmp4, Hes1, and Id3, are upregulated in postnatal brains lacking Tlx. Chromatin immunoprecipitation and electrophoretic mobility shift assays reveal that TLX can directly bind the enhancer region of Bmp4. In accordance with elevated BMP signaling, the downstream effectors SMAD1/5/8 are activated by phosphorylation in Tlx mutant mice. Consequently, Tlx mutant brains exhibit an early appearance and increased number of astrocytes with marker expression of glial fibrillary acidic protein (GFAP) and S100B. Taken together, these results suggest that TLX tightly controls postnatal astrogenesis through the modulation of BMP-SMAD signaling pathway activity. PMID:24782704

Orphan nuclear receptor TLX regulates astrogenesis by modulating BMP signaling.

PubMed

Qin, Song; Niu, Wenze; Iqbal, Nida; Smith, Derek K; Zhang, Chun-Li

2014-01-01

Neural stem cells (NSCs) are self-renewing multipotent progenitors that generate both neurons and glia. The precise control of NSC behavior is fundamental to the architecture and function of the central nervous system. We previously demonstrated that the orphan nuclear receptor TLX is required for postnatal NSC activation and neurogenesis in the neurogenic niche. Here, we show that TLX modulates bone morphogenetic protein (BMP)-SMAD signaling to control the timing of postnatal astrogenesis. Genes involved in the BMP signaling pathway, such as Bmp4, Hes1, and Id3, are upregulated in postnatal brains lacking Tlx. Chromatin immunoprecipitation and electrophoretic mobility shift assays reveal that TLX can directly bind the enhancer region of Bmp4. In accordance with elevated BMP signaling, the downstream effectors SMAD1/5/8 are activated by phosphorylation in Tlx mutant mice. Consequently, Tlx mutant brains exhibit an early appearance and increased number of astrocytes with marker expression of glial fibrillary acidic protein (GFAP) and S100B. Taken together, these results suggest that TLX tightly controls postnatal astrogenesis through the modulation of BMP-SMAD signaling pathway activity.

Tibolone protects T98G cells from glucose deprivation.

PubMed

Ávila Rodriguez, Marco; Garcia-Segura, Luis Miguel; Cabezas, Ricardo; Torrente, Daniel; Capani, Francisco; Gonzalez, Janneth; Barreto, George E

2014-10-01

The steroidal drug Tibolone is used for the treatment of climacteric symptoms and osteoporosis in post-menopausal women. Although Tibolone has been shown to exert neuroprotective actions after middle cerebral artery occlusion, its specific actions on glial cells have received very little attention. In the present study we have assessed whether Tibolone exerts protective actions in a human astrocyte cell model, the T98G cells, subjected to glucose deprivation. Our findings indicate that Tibolone decreases the effects of glucose deprivation on cell death, nuclear fragmentation, superoxide ion production, mitochondrial membrane potential, cytoplasmic calcium concentration and morphological parameters. These findings suggest that glial cells may participate in the neuroprotective actions of Tibolone in the brain. Copyright © 2014 Elsevier Ltd. All rights reserved.

K+ channels of Müller glial cells in retinal disorders.

PubMed

Gao, Feng; Xu, Linjie; Zhao, Yuan; Sun, Xinghuai; Wang, Zhongfeng

2018-02-01

Müller cell is the major type glial cell in the vertebrate retina. Müller cells express various types of K+ channels, such as inwardly rectifying K+ (Kir) channels, big conductance Ca2+-activated K+ (BKCa) channels, delayed rectifier K+ channels (KDR), and transient A-type K+ channels. These K+ channels play important roles in maintaining physiological functions of Müller cells. Under some retinal pathological conditions, the changed expression and functions of K+ channels may contribute to retinal pathogenesis. In this article, we reviewed the physiological properties of K+ channels in retinal Müller cells and the functional changes of these channels in retinal disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Podoplanin increases migration and angiogenesis in malignant glioma

PubMed Central

Grau, Stefan J; Trillsch, Fabian; Tonn, Joerg-Christian; Goldbrunner, Roland H; Noessner, Elfriede; Nelson, Peter J; von Luettichau, Irene

2015-01-01

Expression of podoplanin in glial brain tumors is grade dependent. While serving as a marker for tumor progression and modulating invasion in various neoplasms, little is known about podoplanin function in gliomas. Therefore we stably transfected two human glioma cell lines (U373MG and U87MG) with expression plasmids encoding podoplanin. The efficacy of transfection was confirmed by FACS analysis, PCR and immunocytochemistry. Cells were then sorted for highly podoplanin expressing cells (U373Phigh/U87Phigh). Transfection did not influence the production of pro-angiogenic factors including VEGF, VEGF-C and D. Also, expression of VEGF receptors (VEGFR) remained unchanged except for U87Phigh, where a VEGFR3 expression was induced. U373Phigh showed significantly reduced proliferation as compared to mock transfected group. By contrast, podoplanin significantly increased migration and invasion into collagen matrix. Furthermore, conditioned media from Phigh glioma cells strongly induced tube formation on matrigel. In conclusion, podoplanin increased migration of tumor cells and enhanced tube formation activity in endothelial cells independent from VEGF. Thus, podoplanin expression may be an important step in tumor progression. PMID:26339454

Ammonia modifies enteric neuromuscular transmission through glial γ-aminobutyric acid signaling.

PubMed

Fried, David E; Watson, Ralph E; Robson, Simon C; Gulbransen, Brian D

2017-12-01

Impaired gut motility may contribute, at least in part, to the development of systemic hyperammonemia and systemic neurological disorders in inherited metabolic disorders, or in severe liver and renal disease. It is not known whether enteric neurotransmission regulates intestinal luminal and hence systemic ammonia levels by induced changes in motility. Here, we propose and test the hypothesis that ammonia acts through specific enteric circuits to influence gut motility. We tested our hypothesis by recording the effects of ammonia on neuromuscular transmission in tissue samples from mice, pigs, and humans and investigated specific mechanisms using novel mutant mice, selective drugs, cellular imaging, and enzyme-linked immunosorbent assays. Exogenous ammonia increased neurogenic contractions and decreased neurogenic relaxations in segments of mouse, pig, and human intestine. Enteric glial cells responded to ammonia with intracellular Ca 2+ responses. Inhibition of glutamine synthetase and the deletion of glial connexin-43 channels in hGFAP :: Cre ER T2+/- /connexin43 f/f mice potentiated the effects of ammonia on neuromuscular transmission. The effects of ammonia on neuromuscular transmission were blocked by GABA A receptor antagonists, and ammonia drove substantive GABA release as did the selective pharmacological activation of enteric glia in GFAP::hM3Dq transgenic mice. We propose a novel mechanism whereby local ammonia is operational through GABAergic glial signaling to influence enteric neuromuscular circuits that regulate intestinal motility. Therapeutic manipulation of these mechanisms may benefit a number of neurological, hepatic, and renal disorders manifesting hyperammonemia. NEW & NOTEWORTHY We propose that local circuits in the enteric nervous system sense and regulate intestinal ammonia. We show that ammonia modifies enteric neuromuscular transmission to increase motility in human, pig, and mouse intestine model systems. The mechanisms underlying the effects of ammonia on enteric neurotransmission include GABAergic pathways that are regulated by enteric glial cells. Our new data suggest that myenteric glial cells sense local ammonia and directly modify neurotransmission by releasing GABA. Copyright © 2017 the American Physiological Society.

Distribution of Clostridium perfringens epsilon toxin in the brains of acutely intoxicated mice and its effect upon glial cells.

PubMed

Soler-Jover, Alex; Dorca, Jonatan; Popoff, Michel R; Gibert, Maryse; Saura, Josep; Tusell, Josep Maria; Serratosa, Joan; Blasi, Juan; Martín-Satué, Mireia

2007-09-15

Epsilon toxin (epsilon-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxaemia in livestock. The disease is principally manifested as severe and often fatal neurological disturbance. Oedema of several organs, including the brain, is also a clinical sign related to microvascular damage. Recombinant epsilon-toxin-green fluorescence protein (epsilon-toxin-GFP) and epsilon-prototoxin-GFP have already been characterised as useful tools to track their distribution in intravenously injected mice, by means of direct fluorescence microscopy detection. The results shown here, using an acutely intoxicated mouse model, strongly suggest that epsilon-toxin-GFP, but not epsilon-prototoxin-GFP, not only causes oedema but is also able to cross the blood-brain barrier and accumulate in brain tissue. In some brain areas, epsilon-toxin-GFP is found bound to glial cells, both astrocytes and microglia. Moreover, cytotoxicity assays, performed with mixed glial primary cultures, demonstrate the cytotoxic effect of epsilon-toxin upon both astrocytes and microglial cells.

Glial cells isolated from dorsal root ganglia express prostaglandin E(2) (EP(4)) and prostacyclin (IP) receptors.

PubMed

Ng, Kai Yu; Wong, Yung Hou; Wise, Helen

2011-07-01

Isolated cells from adult rat dorsal root ganglia (DRG) are frequently used as a model system to study responses of primary sensory neurons to nociceptor sensitizing agents such as prostaglandin E(2) and prostacyclin, which are presumed to act only on the neurons in typical mixed cell cultures. In the present study, we evaluated the expression of prostaglandin E(2) (EP(4)) and prostacyclin (IP) receptors in cultures of mixed DRG cells and in purified DRG glia. We show here that EP(4) and IP receptor agonists stimulated adenylyl cyclase activity in both mixed DRG cells and in purified DRG glia, and that these responses were specifically inhibited by EP(4) and IP receptor antagonists, respectively. The presence of EP(4) and IP receptors in DRG glia was further confirmed by the expression of EP(4) and IP receptor immunoreactivity and mRNA. With the increasing awareness of neuron-glial interactions within intact DRG and the use of isolated DRG cells in the study of mechanisms underlying nociception, it will be essential to consider the role played by EP(4) and IP receptor-expressing glial cells when evaluating prostanoid-induced sensitization of DRG neurons. Copyright © 2011 Elsevier B.V. All rights reserved.

Environmental stress, ageing and glial cell senescence: a novel mechanistic link to Parkinson's disease?

PubMed

Chinta, S J; Lieu, C A; Demaria, M; Laberge, R-M; Campisi, J; Andersen, J K

2013-05-01

Exposure to environmental toxins is associated with a variety of age-related diseases including cancer and neurodegeneration. For example, in Parkinson's disease (PD), chronic environmental exposure to certain toxins has been linked to the age-related development of neuropathology. Neuronal damage is believed to involve the induction of neuroinflammatory events as a consequence of glial cell activation. Cellular senescence is a potent anti-cancer mechanism that occurs in a number of proliferative cell types and causes the arrest of proliferation of cells at risk of malignant transformation following exposure to potentially oncogenic stimuli. With age, senescent cells accumulate and express a senescence-associated secretory phenotype (SASP; that is the robust secretion of many inflammatory cytokines, growth factors and proteases). Whereas cell senescence in peripheral tissues has been causally linked to a number of age-related pathologies, little is known about the induction of cellular senescence and the SASP in the brain. On the basis of recently reported findings, we propose that environmental stressors associated with PD may act in part by eliciting senescence and the SASP within non neuronal glial cells in the ageing brain, thus contributing to the characteristic decline in neuronal integrity that occurs in this disorder. © 2013 The Association for the Publication of the Journal of Internal Medicine.

Glial reactions to argon laser photocoagulation injury in rabbit and rat retinas

NASA Astrophysics Data System (ADS)

Humphrey, Martin F.; Chu, Yi; Sharp, Claudia; Moore, Stephen; Mann, Krishna; Rakoczy, Piroska; Constable, Ian J.

1996-04-01

Argon laser photocoagulation is a standard and effective clinical technique for a variety of disease conditions. However there is evidence that coagulation produces more widespread alterations in the retina than the local scarring at the injury site. For example, in diabetic retinopathy multiple photocoagulations in the retinal periphery can control blood vessel growth in the central retina. Therefore we have studied the changes in retinal glial cells following photocoagulation using immunocytochemical techniques with an emphasis on the spread of cellular reactions by using whole, flatmounted retinal preparations. Muller glial cells do not normally express the cytoskeletal protein GFAP (glial fibrillary acidic protein) but do so after a variety of injuries. We found that there is a very widespread expression of GFAP by Muller cells even after very focal coagulations and that this persists for 1 - 1.5 months after coagulation. The microglial cells are primed to react to injury and can release very powerful effector molecules and we therefore also examined the microglial reaction to see whether it correlated with the Muller cell reaction. However, we found that the microglial response, in terms of anatomical changes, was very focally confined to regions of direct cellular injury. We also examined MHC II expression to see whether microglia expressed this activity related protein without anatomical changes but we found no evidence of wide spread changes. In summary we find that inflammatory reactions are very localized after coagulation but the macroglial changes are more widespread and therefore the distant effects of photocoagulation may be more related to macroglial reactions.

Homer1a protein expression in schizophrenia, bipolar disorder, and major depression.

PubMed

Leber, Stefan L; Llenos, Ida C; Miller, Christine L; Dulay, Jeannette R; Haybaeck, Johannes; Weis, Serge

2017-10-01

In recent years, there was growing interest in postsynaptic density proteins in the central nervous system. Of the most important candidates of this specialized region are proteins belonging to the Homer protein family. This family of scaffolding proteins is suspected to participate in the pathogenesis of a variety of diseases. The present study aims to compare Homer1a expression in the hippocampus and cingulate gyrus of patients with major psychiatric disorders including schizophrenia, bipolar disorder and major depression. Immunohistochemistry was used to analyze changes of Homer1a protein expression in the hippocampal formation and the cingulate gyrus from the respective disease groups. Glial cells of the cingulate gyrus gray matter showed decreased Homer1a levels in bipolar disorder when compared to controls. The same results were seen when comparing cingulate gyrus gray matter glial cells in bipolar disorder with major depression. Stratum oriens glial cells of the hippocampus showed decreased Homer1a levels in bipolar disorder when compared to controls and major depression. Stratum lacunosum glial cells showed decreased Homer1a levels in bipolar disorder when compared to major depression. In stratum oriens interneurons Homer1a levels were increased in all disease groups when compared to controls. Stratum lucidum axons showed decreased Homer1a levels in bipolar disorder when compared to controls. Our data demonstrate altered Homer1a levels in specific brain regions and cell types of patients suffering from schizophrenia, bipolar disorder and major depression. These findings support the role of Homer proteins as interesting candidates in neuropsychiatric pathophysiology and treatment.

Altered Functional Properties of Satellite Glial Cells in Compressed Spinal Ganglia

PubMed Central

Zhang, Haijun; Mei, Xiaofeng; Zhang, Pu; Ma, Chao; White, Fletcher A; Donnelly, David F; LaMotte, Robert H

2009-01-01

The cell bodies of sensory neurons in the dorsal root ganglion (DRG) are enveloped by satellite glial cells (SGCs). In an animal model of intervertebral foraminal stenosis and low-back pain, a chronic compression of the DRG (CCD) increases the excitability of neuronal cell bodies in the compressed ganglion. The morphological and electrophysiological properties of SGCs were investigated in both CCD and uninjured, control lumbar DRGs. SGCs responded within 12 hours of the onset of CCD as indicated by an increased expression of glial fibrillary acidic protein (GFAP) in the compressed DRG but to lesser extent in neighboring or contralateral DRGs. Within one week, coupling through gap junctions between SGCs was significantly enhanced in the compressed ganglion. Under whole-cell patch clamp recordings, inward and outward potassium currents, but not sodium currents, were detected in individual SGCs. SGCs enveloping differently sized neurons had similar electrophysiological properties. SGCs in the compressed vs. control DRG exhibited significantly reduced inwardly rectifying potassium currents (Kir), increased input resistances and positively shifted resting membrane potentials. The reduction in Kir was greater for nociceptive medium-sized neurons compared to non-nociceptive neurons. Kir currents of SGCs around spontaneously active neurons were significantly reduced one day after compression but recovered by 7 days. These data demonstrate rapid alterations in glial membrane currents and GFAP expression in close temporal association with the development of neuronal hyperexcitability in the CCD model of europathic pain. However, these alterations are not fully sustained and suggest other mechanisms for the maintenance of the hyperexcitable state. PMID:19330845

Glial β-oxidation regulates Drosophila energy metabolism.

PubMed

Schulz, Joachim G; Laranjeira, Antonio; Van Huffel, Leen; Gärtner, Annette; Vilain, Sven; Bastianen, Jarl; Van Veldhoven, Paul P; Dotti, Carlos G

2015-01-15

The brain's impotence to utilize long-chain fatty acids as fuel, one of the dogmas in neuroscience, is surprising, since the nervous system is the tissue most energy consuming and most vulnerable to a lack of energy. Challenging this view, we here show in vivo that loss of the Drosophila carnitine palmitoyltransferase 2 (CPT2), an enzyme required for mitochondrial β-oxidation of long-chain fatty acids as substrates for energy production, results in the accumulation of triacylglyceride-filled lipid droplets in adult Drosophila brain but not in obesity. CPT2 rescue in glial cells alone is sufficient to restore triacylglyceride homeostasis, and we suggest that this is mediated by the release of ketone bodies from the rescued glial cells. These results demonstrate that the adult brain is able to catabolize fatty acids for cellular energy production.

Different Levels of Expression of the Clock Protein PER and the Glial Marker REPO in Ensheathing and Astrocyte-Like Glia of the Distal Medulla of Drosophila Optic Lobe

PubMed Central

Krzeptowski, Wojciech; Walkowicz, Lucyna; Płonczyńska, Alicja; Górska-Andrzejak, Jolanta

2018-01-01

Circadian plasticity of the visual system of Drosophila melanogaster depends on functioning of both the neuronal and glial oscillators. The clock function of the former is already quite well-recognized. The latter, however, is much less known and documented. In this study we focus on the glial oscillators that reside in the distal part of the second visual neuropil, medulla (dMnGl), in vicinity of the PIGMENT-DISPERSING FACTOR (PDF) releasing terminals of the circadian clock ventral Lateral Neurons (LNvs). We reveal the heterogeneity of the dMnGl, which express the clock protein PERIOD (PER) and the pan-glial marker REVERSED POLARITY (REPO) at higher (P1) or lower (P2) levels. We show that the cells with stronger expression of PER display also stronger expression of REPO, and that the number of REPO-P1 cells is bigger during the day than during the night. Using a combination of genetic markers and immunofluorescent labeling with anti PER and REPO Abs, we have established that the P1 and P2 cells can be associated with two different types of the dMnGl, the ensheathing (EnGl), and the astrocyte-like glia (ALGl). Surprisingly, the EnGl belong to the P1 cells, whereas the ALGl, previously reported to play the main role in the circadian rhythms, display the characteristics of the P2 cells (express very low level of PER and low level of REPO). Next to the EnGl and ALGl we have also observed another type of cells in the distal medulla that express PER and REPO, although at very low levels. Based on their morphology we have identified them as the T1 interneurons. Our study reveals the complexity of the distal medulla circadian network, which appears to consist of different types of glial and neuronal peripheral clocks, displaying molecular oscillations of higher (EnGl) and lower (ALGl and T1) amplitudes. PMID:29695973

Different Levels of Expression of the Clock Protein PER and the Glial Marker REPO in Ensheathing and Astrocyte-Like Glia of the Distal Medulla of Drosophila Optic Lobe.

PubMed

Krzeptowski, Wojciech; Walkowicz, Lucyna; Płonczyńska, Alicja; Górska-Andrzejak, Jolanta

2018-01-01

Circadian plasticity of the visual system of Drosophila melanogaster depends on functioning of both the neuronal and glial oscillators. The clock function of the former is already quite well-recognized. The latter, however, is much less known and documented. In this study we focus on the glial oscillators that reside in the distal part of the second visual neuropil, medulla (dMnGl), in vicinity of the PIGMENT-DISPERSING FACTOR (PDF) releasing terminals of the circadian clock ventral Lateral Neurons (LNvs). We reveal the heterogeneity of the dMnGl, which express the clock protein PERIOD (PER) and the pan-glial marker REVERSED POLARITY (REPO) at higher (P1) or lower (P2) levels. We show that the cells with stronger expression of PER display also stronger expression of REPO, and that the number of REPO-P1 cells is bigger during the day than during the night. Using a combination of genetic markers and immunofluorescent labeling with anti PER and REPO Abs, we have established that the P1 and P2 cells can be associated with two different types of the dMnGl, the ensheathing (EnGl), and the astrocyte-like glia (ALGl). Surprisingly, the EnGl belong to the P1 cells, whereas the ALGl, previously reported to play the main role in the circadian rhythms, display the characteristics of the P2 cells (express very low level of PER and low level of REPO). Next to the EnGl and ALGl we have also observed another type of cells in the distal medulla that express PER and REPO, although at very low levels. Based on their morphology we have identified them as the T1 interneurons. Our study reveals the complexity of the distal medulla circadian network, which appears to consist of different types of glial and neuronal peripheral clocks, displaying molecular oscillations of higher (EnGl) and lower (ALGl and T1) amplitudes.

A procyanidin type A trimer from cinnamon extract attenuates glial cell swelling and the reduction in glutamate uptake following ischemia-like injury in vitro.

PubMed

Panickar, K S; Polansky, M M; Graves, D J; Urban, J F; Anderson, R A

2012-01-27

Dietary polyphenols exert neuroprotective effects in ischemic injury. The protective effects of a procyanidin type A trimer (trimer 1) isolated from a water soluble cinnamon extract (CE) were investigated on key features of ischemic injury, including cell swelling, increased free radical production, increased intracellular calcium ([Ca(2+)](i)), mitochondrial dysfunction, and the reduction in glutamate uptake. Astrocyte (glial) swelling is a major component of cytotoxic brain edema in ischemia and, along with vasogenic edema, may contribute to increased intracranial pressure, brain herniation, and additional ischemic injuries. C6 glial cultures were exposed to oxygen-glucose deprivation (OGD) for 5 h, and cell swelling was determined at 90 min after the end of OGD. OGD-induced increases in glial swelling were significantly blocked by trimer 1, but not by the major nonpolyphenol fractions of CE including cinnamaldehyde and coumarin. Increased free radical production, a contributing factor in cell swelling following ischemic injury, was also significantly reduced by trimer 1. Mitochondrial dysfunction, another key feature of ischemic injury, is hypothesized to contribute to glial swelling. Depolarization of the inner mitochondrial membrane potential (ΔΨ(m)) was assessed using a fluorescent dye (tetramethylrhodamine ethyl ester [TMRE]), and was significantly attenuated by trimer 1 as was OGD-induced increased [Ca(2+)](i). Taken together with our previous observation that blockers of [Ca(2+)](i) reduce cell swelling, our results indicate that trimer 1 may attenuate cell swelling by regulating [Ca(2+)](i). Trimer 1 also significantly attenuated the OGD-induced decrease in glutamate uptake. In addition, cyclosporin A, a blocker of the mitochondrial permeability pore (mPT), but not FK506 (that does not block the mPT), reduced the OGD-induced decline in glutamate uptake indicating a role of the mPT in such effects. Thus, the effects of trimer 1 in attenuating the reduction in glutamate uptake are likely mediated through their action on the mitochondria. Published by Elsevier Ltd on behalf of IBRO.

Glial cells as key players in schizophrenia pathology: recent insights and concepts of therapy.

PubMed

Bernstein, Hans-Gert; Steiner, Johann; Guest, Paul C; Dobrowolny, Henrik; Bogerts, Bernhard

2015-01-01

The past decade has witnessed an explosion of knowledge on the impact of glia for the neurobiological foundation of schizophrenia. A plethora of studies have shown structural and functional abnormalities in all three types of glial cells. There is convincing evidence of reduced numbers of oligodendrocytes, impaired cell maturation and altered gene expression of myelin/oligodendrocyte-related genes that may in part explain white matter abnormalities and disturbed inter- and intra-hemispheric connectivity, which are characteristic signs of schizophrenia. Earlier reports of astrogliosis could not be confirmed by later studies, although the expression of a variety of astrocyte-related genes is abnormal in psychosis. Since astrocytes play a key role in the synaptic metabolism of glutamate, GABA, monoamines and purines, astrocyte dysfunction may contribute to certain aspects of disturbed neurotransmission in schizophrenia. Finally, increased densities of microglial cells and aberrant expression of microglia-related surface markers in schizophrenia suggest that immunological/inflammatory factors are of considerable relevance for the pathophysiology of psychosis. This review describes current evidence for the multifaceted role of glial cells in schizophrenia and discusses efforts to develop glia-directed therapies for the treatment of the disease. Copyright © 2014 Elsevier B.V. All rights reserved.

A three dimensional in vitro glial scar model to investigate the local strain effects from micromotion around neural implants.

PubMed

Spencer, Kevin C; Sy, Jay C; Falcón-Banchs, Roberto; Cima, Michael J

2017-02-28

Glial scar formation remains a significant barrier to the long term success of neural probes. Micromotion coupled with mechanical mismatch between the probe and tissue is believed to be a key driver of the inflammatory response. In vitro glial scar models present an intermediate step prior to conventional in vivo histology experiments as they enable cell-device interactions to be tested on a shorter timescale, with the ability to conduct broader biochemical assays. No established in vitro models have incorporated methods to assess device performance with respect to mechanical factors. In this study, we describe an in vitro glial scar model that combines high-precision linear actuators to simulate axial micromotion around neural implants with a 3D primary neural cell culture in a collagen gel. Strain field measurements were conducted to visualize the local displacement within the gel in response to micromotion. Primary brain cell cultures were found to be mechanically responsive to micromotion after one week in culture. Astrocytes, as determined by immunohistochemical staining, were found to have significantly increased in cell areas and perimeters in response to micromotion compared to static control wells. These results demonstrate the importance of micromotion when considering the chronic response to neural implants. Going forward, this model provides advantages over existing in vitro models as it will enable critical mechanical design factors of neural implants to be evaluated prior to in vivo testing.

Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia

PubMed Central

Vit, Jean-Philippe; Ohara, Peter T; Sundberg, Christopher; Rubi, Blanca; Maechler, Pierre; Liu, Chunyan; Puntel, Mariana; Lowenstein, Pedro; Castro, Maria; Jasmin, Luc

2009-01-01

Background Our goal is to use gene therapy to alleviate pain by targeting glial cells. In an animal model of facial pain we tested the effect of transfecting the glutamic acid decarboxylase (GAD) gene into satellite glial cells (SGCs) of the trigeminal ganglion by using a serotype 5 adenovector with high tropisms for glial cells. We postulated that GABA produced from the expression of GAD would reduce pain behavior by acting on GABA receptors on neurons within the ganglion. Results Injection of adenoviral vectors (AdGAD65) directly into the trigeminal ganglion leads to sustained expression of the GAD65 isoform over the 4 weeks observation period. Immunohistochemical analysis showed that adenovirus-mediated GAD65 expression and GABA synthesis were mainly in SGCs. GABAA and GABAB receptors were both seen in sensory neurons, yet only GABAA receptors decorated the neuronal surface. GABA receptors were not found on SGCs. Six days after injection of AdGAD65 into the trigeminal ganglion, there was a statistically significant decrease of pain behavior in the orofacial formalin test, a model of inflammatory pain. Rats injected with control virus (AdGFP or AdLacZ) had no reduction in their pain behavior. AdGAD65-dependent analgesia was blocked by bicuculline, a selective GABAA receptor antagonist, but not by CGP46381, a selective GABAB receptor antagonist. Conclusion Transfection of glial cells in the trigeminal ganglion with the GAD gene blocks pain behavior by acting on GABAA receptors on neuronal perikarya. PMID:19656360

Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia.

PubMed

Vit, Jean-Philippe; Ohara, Peter T; Sundberg, Christopher; Rubi, Blanca; Maechler, Pierre; Liu, Chunyan; Puntel, Mariana; Lowenstein, Pedro; Castro, Maria; Jasmin, Luc

2009-08-05

Our goal is to use gene therapy to alleviate pain by targeting glial cells. In an animal model of facial pain we tested the effect of transfecting the glutamic acid decarboxylase (GAD) gene into satellite glial cells (SGCs) of the trigeminal ganglion by using a serotype 5 adenovector with high tropisms for glial cells. We postulated that GABA produced from the expression of GAD would reduce pain behavior by acting on GABA receptors on neurons within the ganglion. Injection of adenoviral vectors (AdGAD65) directly into the trigeminal ganglion leads to sustained expression of the GAD65 isoform over the 4 weeks observation period. Immunohistochemical analysis showed that adenovirus-mediated GAD65 expression and GABA synthesis were mainly in SGCs. GABAA and GABAB receptors were both seen in sensory neurons, yet only GABAA receptors decorated the neuronal surface. GABA receptors were not found on SGCs. Six days after injection of AdGAD65 into the trigeminal ganglion, there was a statistically significant decrease of pain behavior in the orofacial formalin test, a model of inflammatory pain. Rats injected with control virus (AdGFP or AdLacZ) had no reduction in their pain behavior. AdGAD65-dependent analgesia was blocked by bicuculline, a selective GABAA receptor antagonist, but not by CGP46381, a selective GABAB receptor antagonist. Transfection of glial cells in the trigeminal ganglion with the GAD gene blocks pain behavior by acting on GABAA receptors on neuronal perikarya.

Neuroimmune Basis of Methamphetamine Toxicity

PubMed Central

Loftis, Jennifer M.; Janowsky, Aaron

2015-01-01

Although it is not known which antigen-specific immune responses (or if antigen-specific immune responses) are relevant or required for methamphetamine's neurotoxic effects, it is apparent that methamphetamine exposure is associated with significant effects on adaptive and innate immunity. Alterations in lymphocyte activity and number, changes in cytokine signaling, impairments in phagocytic functions, and glial activation and gliosis have all been reported. These drug-induced changes in immune response, particularly within the CNS, are now thought to play a critical role in the addiction process for methamphetamine dependence as well as for other substance use disorders. In Section 2, methamphetamine's effects on glial cell (e.g., microglia and astrocytes) activity and inflammatory signaling cascades are summarized, including how alterations in immune cell function can induce the neurotoxic and addictive effects of methamphetamine. Section 2 also describes neurotransmitter involvement in the modulation of methamphetamine's inflammatory effects. Section 3 discusses the very recent use of pharmacological and genetic animal models which have helped elucidate the behavioral effects of methamphetamine's neurotoxic effects and the role of the immune system. Section 4 is focused on the effects of methamphetamine on blood–brain barrier integrity and associated immune consequences. Clinical considerations such as the combined effects of methamphetamine and HIV and/or HCV on brain structure and function are included in Section 4. Finally, in Section 5, immune-based treatment strategies are reviewed, with a focus on vaccine development, neuroimmune therapies, and other anti-inflammatory approaches. PMID:25175865

TGFβ signaling in the brain increases with aging and signals to astrocytes and innate immune cells in the weeks after stroke.

PubMed

Doyle, Kristian P; Cekanaviciute, Egle; Mamer, Lauren E; Buckwalter, Marion S

2010-10-11

TGFβ is both neuroprotective and a key immune system modulator and is likely to be an important target for future stroke therapy. The precise function of increased TGF-β1 after stroke is unknown and its pleiotropic nature means that it may convey a neuroprotective signal, orchestrate glial scarring or function as an important immune system regulator. We therefore investigated the time course and cell-specificity of TGFβ signaling after stroke, and whether its signaling pattern is altered by gender and aging. We performed distal middle cerebral artery occlusion strokes on 5 and 18 month old TGFβ reporter mice to get a readout of TGFβ responses after stroke in real time. To determine which cell type is the source of increased TGFβ production after stroke, brain sections were stained with an anti-TGFβ antibody, colocalized with markers for reactive astrocytes, neurons, and activated microglia. To determine which cells are responding to TGFβ after stroke, brain sections were double-labelled with anti-pSmad2, a marker of TGFβ signaling, and markers of neurons, oligodendrocytes, endothelial cells, astrocytes and microglia. TGFβ signaling increased 2 fold after stroke, beginning on day 1 and peaking on day 7. This pattern of increase was preserved in old animals and absolute TGFβ signaling in the brain increased with age. Activated microglia and macrophages were the predominant source of increased TGFβ after stroke and astrocytes and activated microglia and macrophages demonstrated dramatic upregulation of TGFβ signaling after stroke. TGFβ signaling in neurons and oligodendrocytes did not undergo marked changes. We found that TGFβ signaling increases with age and that astrocytes and activated microglia and macrophages are the main cell types that undergo increased TGFβ signaling in response to post-stroke increases in TGFβ. Therefore increased TGFβ after stroke likely regulates glial scar formation and the immune response to stroke.

Synaptic multistability and network synchronization induced by the neuron-glial interaction in the brain

NASA Astrophysics Data System (ADS)

Lazarevich, I. A.; Stasenko, S. V.; Kazantsev, V. B.

2017-02-01

The dynamics of a synaptic contact between neurons that forms a feedback loop through the interaction with glial cells of the brain surrounding the neurons is studied. It is shown that, depending on the character of the neuron-glial interaction, the dynamics of the signal transmission frequency in the synaptic contact can be bistable with two stable steady states or spiking with the regular generation of spikes with various amplitudes and durations. It is found that such a synaptic contact at the network level is responsible for the appearance of quasisynchronous network bursts.

Neuronal somatic ATP release triggers neuron–satellite glial cell communication in dorsal root ganglia

PubMed Central

Zhang, X.; Chen, Y.; Wang, C.; Huang, L.-Y. M.

2007-01-01

It has been generally assumed that the cell body (soma) of a neuron, which contains the nucleus, is mainly responsible for synthesis of macromolecules and has a limited role in cell-to-cell communication. Using sniffer patch recordings, we show here that electrical stimulation of dorsal root ganglion (DRG) neurons elicits robust vesicular ATP release from their somata. The rate of release events increases with the frequency of nerve stimulation; external Ca2+ entry is required for the release. FM1–43 photoconversion analysis further reveals that small clear vesicles participate in exocytosis. In addition, the released ATP activates P2X7 receptors in satellite cells that enwrap each DRG neuron and triggers the communication between neuronal somata and glial cells. Blocking L-type Ca2+ channels completely eliminates the neuron–glia communication. We further show that activation of P2X7 receptors can lead to the release of tumor necrosis factor-α (TNFα) from satellite cells. TNFα in turn potentiates the P2X3 receptor-mediated responses and increases the excitability of DRG neurons. This study provides strong evidence that somata of DRG neurons actively release transmitters and play a crucial role in bidirectional communication between neurons and surrounding satellite glial cells. These results also suggest that, contrary to the conventional view, neuronal somata have a significant role in cell–cell signaling. PMID:17525149

Impact of heme oxygenase-1 on cholesterol synthesis, cholesterol efflux and oxysterol formation in cultured astroglia.

PubMed

Hascalovici, Jacob R; Song, Wei; Vaya, Jacob; Khatib, Soliman; Fuhrman, Bianca; Aviram, Michael; Schipper, Hyman M

2009-01-01

Up-regulation of heme oxygenase-1 (HO-1) and altered cholesterol (CH) metabolism are characteristic of Alzheimer-diseased neural tissues. The liver X receptor (LXR) is a molecular sensor of CH homeostasis. In the current study, we determined the effects of HO-1 over-expression and its byproducts iron (Fe(2+)), carbon monoxide (CO) and bilirubin on CH biosynthesis, CH efflux and oxysterol formation in cultured astroglia. HO-1/LXR interactions were also investigated in the context of CH efflux. hHO-1 over-expression for 3 days ( approximately 2-3-fold increase) resulted in a 30% increase in CH biosynthesis and a two-fold rise in CH efflux. Both effects were abrogated by the competitive HO inhibitor, tin mesoporphyrin. CO, released from administered CORM-3, significantly enhanced CH biosynthesis; a combination of CO and iron stimulated CH efflux. Free iron increased oxysterol formation three-fold. Co-treatment with LXR antagonists implicated LXR activation in the modulation of CH homeostasis by heme degradation products. In Alzheimer's disease and other neuropathological states, glial HO-1 induction may transduce ambient noxious stimuli (e.g. beta-amyloid) into altered patterns of glial CH homeostasis. As the latter may impact synaptic plasticity and neuronal repair, modulation of glial HO-1 expression (by pharmacological or other means) may confer neuroprotection in patients with degenerative brain disorders.

Innate immune responses in central nervous system inflammation.

PubMed

Finsen, Bente; Owens, Trevor

2011-12-01

In autoimmune diseases of the central nervous system (CNS), innate glial cell responses play a key role in determining the outcome of leukocyte infiltration. Access of leukocytes is controlled via complex interactions with glial components of the blood-brain barrier that include angiotensin II receptors on astrocytes and immunoregulatory mediators such as Type I interferons which regulate cellular traffic. Myeloid cells at the blood-brain barrier present antigen to T cells and influence cytokine effector function. Myelin-specific T cells interact with microglia and promote differentiation of oligodendrocyte precursor cells in response to axonal injury. These innate responses offer potential targets for immunomodulatory therapy. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

AUTOSENSITIZATION REACTION IN VITRO

PubMed Central

Koprowski, Hilary; Fernandes, Mario V.

1962-01-01

Lymph node cells were obtained from an inbred strain of Lewis rats injected with guinea pig cord tissue in Freund's adjuvant. These cells, when added to tissue culture monolayers of puppy brain, aggregated on or around the glial elements. This reaction, called contactual agglutination, was followed by the specific destruction of glial cells, leaving cultures consisting only of fibroblasts. No such reaction was noted when lymph node cells obtained either from normal rats or those injected with adjuvant alone were used. Absorption of serum obtained from rats injected with guinea pig cord tissue by non-sensitized lymph node cells made them reactive in brain tissue culture. The contactual agglutination test seems to provide an opportunity for investigation of sensitization reaction in tissue culture systems. PMID:14034719

Neuroglial modulation in peripheral sensory systems.

PubMed

Pack, Adam K; Pawson, Lorraine J

2010-08-01

Glia are increasingly appreciated as active participants in central neural processing via calcium waves, electrical coupling, and even synaptic-like release of "neuro"-transmitters. In some sensory organs (e.g., retina, olfactory bulb), glia have been shown to interact with neurons in the same manner, although their role in perception has yet to be elucidated. In the organ of Corti, synapses occur between supporting cells and neurons. In one sensory organ, the Pacinian corpuscle (fine touch), glia have been shown to play just as important a role in sensory transduction as they do in neural processing in the brain, and the functional role is quite clear; the modified Schwann cells of the capsule are responsible for the rapid adaptation process of the PCs, integral to its function as a vibration detector. This complex glial/neuronal relationship may be a recent evolutionary phenomenon and may account for much of the relative sophistication of vertebrate nervous systems.

Neural differentiation of adipose-derived stem cells isolated from GFP transgenic mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fujimura, Juri; Department of Pediatrics, Nippon Medical School, Tokyo; E-mail: juri-f@nms.ac.jp

2005-07-22

Taking advantage of homogeneously marked cells from green fluorescent protein (GFP) transgenic mice, we have recently reported that adipose-derived stromal cells (ASCs) could differentiate into mesenchymal lineages in vitro. In this study, we performed neural induction using ASCs from GFP transgenic mice and were able to induce these ASCs into neuronal and glial cell lineages. Most of the neurally induced cells showed bipolar or multipolar appearance morphologically and expressed neuronal markers. Electron microscopy revealed their neuronal morphology. Some cells also showed glial phenotypes, as shown immunocytochemically. The present study clearly shows that ASCs derived from GFP transgenic mice differentiate intomore » neural lineages in vitro, suggesting that these cells might provide an ideal source for further neural stem cell research with possible therapeutic application for neurological disorders.« less

A complex between contactin-1 and the protein tyrosine phosphatase PTPRZ controls the development of oligodendrocyte precursor cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamprianou, Smaragda; Chatzopoulou, Elli; Thomas, Jean-Léon

The six members of the contactin (CNTN) family of neural cell adhesion molecules are involved in the formation and maintenance of the central nervous system (CNS) and have been linked to mental retardation and neuropsychiatric disorders such as autism. Five of the six CNTNs bind to the homologous receptor protein tyrosine phosphatases gamma (PTPRG) and zeta (PTPRZ), but the biological roles of these interactions remain unclear. We report here the cocrystal structure of the carbonic anhydrase-like domain of PTPRZ bound to tandem Ig repeats of CNTN1 and combine these structural data with binding assays to show that PTPRZ binds specificallymore » to CNTN1 expressed at the surface of oligodendrocyte precursor cells. Furthermore, analyses of glial cell populations in wild-type and PTPRZ-deficient mice show that the binding of PTPRZ to CNTN1 expressed at the surface of oligodendrocyte precursor cells inhibits their proliferation and promotes their development into mature oligodendrocytes. Overall, these results implicate the PTPRZ/CNTN1 complex as a previously unknown modulator of oligodendrogenesis.« less

The cholinergic anti-inflammatory pathway: An innovative treatment strategy for neurological diseases.

PubMed

Han, Bin; Li, Xiuping; Hao, Junwei

2017-06-01

Acetylcholine (ACh), as a classical neurotransmitter, regulates the neuronal network in response to internal and external stimuli. In recent decades, the biology of ACh has been endowed with unparalleled new insights, especially with respect to cholinergic anti-inflammatory properties in non-neuronal cells. In fact, a mechanism frequently referred to as the "cholinergic anti-inflammatory pathway" has been termed to describe interactions between the central nervous system (CNS) and the immune system via vagus nerve. As well documented, immune cells express choline acetyltransferase, a direct synthetase for ACh, and other corresponding cholinergic components. Alternatively, the ACh released from immune cells or cholinergic neurons modulates immune function in an autocrine/paracrine manner by acting on its receptors. Moreover, muscarinic or nicotinic ACh receptors on various immune cells and CNS glial cells administer the work of their respective agonists, causing functional and biochemical changes. In this review, we focus on the anti-inflammatory benefits of non-neuronal and neuronal ACh as a means of providing new insights into treating inflammation-related neurological diseases, as exemplified by those described herein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intracellular Protein Shuttling: A Mechanism Relevant for Myelin Repair in Multiple Sclerosis?

PubMed Central

Göttle, Peter; Küry, Patrick

2015-01-01

A prominent feature of demyelinating diseases such as multiple sclerosis (MS) is the degeneration and loss of previously established functional myelin sheaths, which results in impaired signal propagation and axonal damage. However, at least in early disease stages, partial replacement of lost oligodendrocytes and thus remyelination occur as a result of resident oligodendroglial precursor cell (OPC) activation. These cells represent a widespread cell population within the adult central nervous system (CNS) that can differentiate into functional myelinating glial cells to restore axonal functions. Nevertheless, the spontaneous remyelination capacity in the adult CNS is inefficient because OPCs often fail to generate new oligodendrocytes due to the lack of stimulatory cues and the presence of inhibitory factors. Recent studies have provided evidence that regulated intracellular protein shuttling is functionally involved in oligodendroglial differentiation and remyelination activities. In this review we shed light on the role of the subcellular localization of differentiation-associated factors within oligodendroglial cells and show that regulation of intracellular localization of regulatory factors represents a crucial process to modulate oligodendroglial maturation and myelin repair in the CNS. PMID:26151843

Early-life experience decreases drug-induced reinstatement of morphine CPP in adulthood via microglial-specific epigenetic programming of anti-inflammatory IL-10 expression.

PubMed

Schwarz, Jaclyn M; Hutchinson, Mark R; Bilbo, Staci D

2011-12-07

A critical component of drug addiction research involves identifying novel biological mechanisms and environmental predictors of risk or resilience to drug addiction and associated relapse. Increasing evidence suggests microglia and astrocytes can profoundly affect the physiological and addictive properties of drugs of abuse, including morphine. We report that glia within the rat nucleus accumbens (NAcc) respond to morphine with an increase in cytokine/chemokine expression, which predicts future reinstatement of morphine conditioned place preference (CPP) following a priming dose of morphine. This glial response to morphine is influenced by early-life experience. A neonatal handling paradigm that increases the quantity and quality of maternal care significantly increases baseline expression of the anti-inflammatory cytokine IL-10 within the NAcc, attenuates morphine-induced glial activation, and prevents the subsequent reinstatement of morphine CPP in adulthood. IL-10 expression within the NAcc and reinstatement of CPP are negatively correlated, suggesting a protective role for this specific cytokine against morphine-induced glial reactivity and drug-induced reinstatement of morphine CPP. Neonatal handling programs the expression of IL-10 within the NAcc early in development, and this is maintained into adulthood via decreased methylation of the IL-10 gene specifically within microglia. The effect of neonatal handling is mimicked by pharmacological modulation of glia in adulthood with ibudilast, which increases IL-10 expression, inhibits morphine-induced glial activation within the NAcc, and prevents reinstatement of morphine CPP. Taken together, we have identified a novel gene × early-life environment interaction on morphine-induced glial activation and a specific role for glial activation in drug-induced reinstatement of drug-seeking behavior.

Early-Life Experience Decreases Drug-Induced Reinstatement of Morphine CPP in Adulthood via Microglial-Specific Epigenetic Programming of Anti-Inflammatory IL-10 Expression

PubMed Central

Schwarz, Jaclyn M.; Hutchinson, Mark R.; Bilbo, Staci D.

2012-01-01

A critical component of drug addiction research involves identifying novel biological mechanisms and environmental predictors of risk or resilience to drug addiction and associated relapse. Increasing evidence suggests microglia and astrocytes can profoundly affect the physiological and addictive properties of drugs of abuse, including morphine. We report that glia within the rat Nucleus Accumbens (NAcc) respond to morphine with an increase in cytokine/chemokine expression, which predicts future reinstatement of morphine conditioned place preference (CPP) following a priming dose of morphine. This glial response to morphine is influenced by early-life experience. A neonatal handling paradigm that increases the quantity and quality of maternal care significantly increases baseline expression of the anti-inflammatory cytokine IL-10 within the NAcc, attenuates morphine-induced glial activation, and prevents the subsequent reinstatement of morphine CPP in adulthood. IL-10 expression within the NAcc and reinstatement of CPP are negatively correlated, suggesting a protective role for this specific cytokine against morphine-induced glial reactivity and drug-induced reinstatement of morphine CPP. Neonatal handling programs the expression of IL-10 within the NAcc early in development, and this is maintained into adulthood via decreased methylation of the IL-10 gene specifically within microglia. The effect of neonatal handling is mimicked by pharmacological modulation of glia in adulthood with Ibudilast, which increases IL-10 expression, inhibits morphine-induced glial activation within the NAcc, and prevents reinstatement of morphine CPP. Taken together, we have identified a novel gene X early-life environment interaction on morphine-induced glial activation, and a specific role for glial activation in drug-induced reinstatement of drug-seeking behavior. PMID:22159099

Hypoxia Response Element-Regulated MMP-9 Promotes Neurological Recovery via Glial Scar Degradation and Angiogenesis in Delayed Stroke.

PubMed

Cai, Hongxia; Ma, Yuanyuan; Jiang, Lu; Mu, Zhihao; Jiang, Zhen; Chen, Xiaoyan; Wang, Yongting; Yang, Guo-Yuan; Zhang, Zhijun

2017-06-07

Matrix metalloproteinase 9 (MMP-9) plays a beneficial role in the delayed phase of middle cerebral artery occlusion (MCAO). However, the mechanism is obscure. Here, we constructed hypoxia response element (HRE)-regulated MMP-9 to explore its effect on glial scars and neurogenesis in delayed ischemic stroke. Adult male Institute of Cancer Research (ICR) mice underwent MCAO and received a stereotactic injection of lentivirus carrying HRE-MMP-9 or normal saline (NS)/lentivirus-GFP 7 days after ischemia. We found that HRE-MMP-9 improved neurological outcomes, reduced ischemia-induced brain atrophy, and degraded glial scars (p < 0.05). Furthermore, HRE-MMP-9 increased the number of microvessels in the peri-infarct area (p < 0.001), which may have been due to the accumulation of endogenous endothelial progenitor cells (EPCs) in the peri-infarct area after glial scar degradation. Finally, HRE-MMP-9 increased the number of bromodeoxyuridine-positive (BrdU + )/NeuN + cells and the expression of PSD-95 in the peri-infarct area (p < 0.01). These changes could be blocked by vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor SU5416 and MMP-9 inhibitor 2-[[(4-phenoxyphenyl)sulfonyl]methyl]-thiirane (SB-3CT). Our results provided a novel mechanism by which glial scar degradation and vascular endothelial growth factor (VEGF)/VEGFR2-dependent angiogenesis may be key procedures for neurological recovery in delayed ischemic stroke after HRE-MMP-9 treatment. Therefore, HRE-MMP-9 overexpression in the delayed ischemic brain is a promising approach for neurological recovery. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Desired and side effects of the supplementation with l-glutamine and l-glutathione in enteric glia of diabetic rats.

PubMed

Panizzon, Cynthia Priscilla do Nascimento Bonato; Zanoni, Jacqueline Nelisis; Hermes-Uliana, Catchia; Trevizan, Aline Rosa; Sehaber, Camila Caviquioli; Pereira, Renata Virginia Fernandes; Linden, David Robert; Neto, Marcílio Hubner de Miranda

2016-07-01

Enteric neuropathy associated with Diabetes Mellitus causes dysfunction in the digestive system, such as: nausea, diarrhea, constipation, vomiting, among others. The aim of this study was to compare the effects of supplementation with 2% l-glutamine and 1% l-glutathione on neurons and enteric glial cells of ileum of diabetic rats. Thirty male Wistar rats have been used according to these group distributions: Normoglycemic (N), Normoglycemic supplemented with l-glutamine (NG), Normoglycemic supplemented with l-glutathione (NGO), Diabetic (D), Diabetic supplemented with l-glutamine (DG) and Diabetic supplemented with l-glutathione (DGO). After 120days, the ileum was processed for immunohistochemistry of HuC/D and S100β. Quantitative and morphometric analysis have been performed. Diabetic rats presented a decrease in the number of neurons when compared to normoglycemic animals. However, diabetes was not associated with a change in glial density. l-Glutathione prevented the neuronal death in diabetic rats. l-Glutathione increased a glial proliferation in diabetic rats. The neuronal area in diabetic rats increased in relation to the normoglycemics. The diabetic rats supplemented with l-glutamine and l-glutathione showed a smaller neuronal area in comparison to diabetic group. The glial cell area was a decreased in the diabetics. The diabetic rats supplemented with l-glutamine and l-glutathione did not have significant difference in the glial cell body area when compared to diabetic rats. It is concluded that the usage of l-glutamine and l-glutathione as supplements presents both desired and side effects that are different for the same substance in considering normoglycemic or diabetic animals. Copyright © 2016 Elsevier GmbH. All rights reserved.

Glial alterations from early to late stages in a model of Alzheimer's disease: Evidence of autophagy involvement in Aβ internalization.

PubMed

Pomilio, Carlos; Pavia, Patricio; Gorojod, Roxana Mayra; Vinuesa, Angeles; Alaimo, Agustina; Galvan, Veronica; Kotler, Monica Lidia; Beauquis, Juan; Saravia, Flavia

2016-02-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease without effective therapy. Brain amyloid deposits are classical histopathological hallmarks that generate an inflammatory reaction affecting neuronal and glial function. The identification of early cell responses and of brain areas involved could help to design new successful treatments. Hence, we studied early alterations of hippocampal glia and their progression during the neuropathology in PDAPP-J20 transgenic mice, AD model, at 3, 9, and 15 months (m) of age. At 3 m, before deposits formation, microglial Iba1+ cells from transgenic mice already exhibited signs of activation and larger soma size in the hilus, alterations appearing later on stratum radiatum. Iba1 immunohistochemistry revealed increased cell density and immunoreactive area in PDAPP mice from 9 m onward selectively in the hilus, in coincidence with prominent amyloid Congo red + deposition. At pre-plaque stages, GFAP+ astroglia showed density alterations while, at an advanced age, the presence of deposits was associated with important glial volume changes and apparently being intimately involved in amyloid degradation. Astrocytes around plaques were strongly labeled for LC3 until 15 m in Tg mice, suggestive of increased autophagic flux. Moreover, β-Amyloid fibrils internalization by astrocytes in in vitro conditions was dependent on autophagy. Co-localization of Iba1 with ubiquitin or p62 was exclusively found in microglia contacting deposits from 9 m onward, suggesting torpid autophagy. Our work characterizes glial changes at early stages of the disease in PDAPP-J20 mice, focusing on the hilus as an especially susceptible hippocampal subfield, and provides evidence that glial autophagy could play a role in amyloid processing at advanced stages. © 2015 Wiley Periodicals, Inc.

Glial Alterations From Early to Late Stages in a Model of Alzheimer’s Disease: Evidence of Autophagy Involvement in Aβ Internalization

PubMed Central

Pomilio, Carlos; Pavia, Patricio; Gorojod, Roxana Mayra; Vinuesa, Angeles; Alaimo, Agustina; Galvan, Veronica; Kotler, Monica Lidia; Beauquis, Juan; Saravia, Flavia

2017-01-01

Alzheimer’s disease (AD) is a progressive neurodegenerative disease without effective therapy. Brain amyloid deposits are classical histopathological hallmarks that generate an inflammatory reaction affecting neuronal and glial function. The identification of early cell responses and of brain areas involved could help to design new successful treatments. Hence, we studied early alterations of hippocampal glia and their progression during the neuropathology in PDAPP-J20 transgenic mice, AD model, at 3, 9, and 15 months (m) of age. At 3 m, before deposits formation, microglial Iba1 + cells from transgenic mice already exhibited signs of activation and larger soma size in the hilus, alterations appearing later on stratum radiatum. Iba1 immunohistochemistry revealed increased cell density and immunoreactive area in PDAPP mice from 9 m onward selectively in the hilus, in coincidence with prominent amyloid Congo red + deposition. At pre-plaque stages, GFAP+ astroglia showed density alterations while, at an advanced age, the presence of deposits was associated with important glial volume changes and apparently being intimately involved in amyloid degradation. Astrocytes around plaques were strongly labeled for LC3 until 15 m in Tg mice, suggestive of increased autophagic flux. Moreover, β-Amyloid fibrils internalization by astrocytes in in vitro conditions was dependent on autophagy. Co-localization of Iba1 with ubiquitin or p62 was exclusively found in microglia contacting deposits from 9 m onward, suggesting torpid autophagy. Our work characterizes glial changes at early stages of the disease in PDAPP-J20 mice, focusing on the hilus as an especially susceptible hippocampal subfield, and provides evidence that glial autophagy could play a role in amyloid processing at advanced stages. PMID:26235241

Glial activation and post-synaptic neurotoxicity: the key events in Streptozotocin (ICV) induced memory impairment in rats.

PubMed

Rai, Shivika; Kamat, Pradeep K; Nath, Chandishwar; Shukla, Rakesh

2014-02-01

In the present study the role of glial activation and post synaptic toxicity in ICV Streptozotocin (STZ) induced memory impaired rats was explored. In experiment set up 1: Memory deficit was found in Morris water maze test on 14-16 days after STZ (ICV; 3mg/Kg) administration. STZ causes increased expression of GFAP, CD11b and TNF-α indicating glial activation and neuroinflammation. STZ also significantly increased the level of ROS, nitrite, Ca(2+) and reduced the mitochondrial activity in synaptosomal preparation illustrating free radical generation and excitotoxicity. Increased expression and activity of Caspase-3 was also observed in STZ treated rat which specify apoptotic cell death in hippocampus and cortex. STZ treatment showed decrease expression of post synaptic markers CaMKIIα and PSD-95, while, expression of pre synaptic markers (synaptophysin and SNAP-25) remains unaltered indicating selective post synaptic neurotoxicity. Oral treatment with Memantine (10mg/kg) and Ibuprofen (50 mg/kg) daily for 13 days attenuated STZ induced glial activation, apoptotic cell death and post synaptic neurotoxicity in rat brain. Further, in experiment set up 2: where memory function was not affected i.e. 7-9 days after STZ treatment. The level of GFAP, CD11b, TNF-α, ROS and nitrite levels were increased. On the other hand, apoptotic marker, synaptic markers, mitochondrial activity and Ca(2+) levels remained unaffected. Collective data indicates that neuroinflammatory process and oxidative stress occurs earlier to apoptosis and does not affect memory function. Present study clearly suggests that glial activation and post synaptic neurotoxicity are the key factors in STZ induced memory impairment and neuronal cell death. Copyright © 2013 Elsevier Inc. All rights reserved.

Conditional Müller cell ablation causes independent neuronal and vascular pathologies in a novel transgenic model

PubMed Central

Shen, Weiyong; Fruttiger, Marcus; Zhu, Ling; Chung, Sook H.; Barnett, Nigel L.; Kirk, Joshua K.; Lee, SoRa; Coorey, Nathan J.; Killingsworth, Murray; Sherman, Larry S.; Gillies, Mark C.

2014-01-01

Müller cells are the major glia of the retina that serve numerous functions essential to retinal homeostasis, yet the contribution of Müller glial dysfunction to retinal diseases remains largely unknown. We have developed a transgenic model using a portion of the regulatory region of the retinaldehyde binding protein 1 gene for conditional Müller cell ablation and the consequences of primary Müller cell dysfunction have been studied in adult mice. We found that selective ablation of Müller cells led to photoreceptor apoptosis, vascular telangiectasis, blood-retinal barrier breakdown and, later, intraretinal neovascularization. These changes were accompanied by impaired retinal function and an imbalance between vascular endothelial growth factor-A (VEGF-A) and pigment epithelium derived factor. Intravitreal injection of cilliary neurotrophic factor inhibited photoreceptor injury but had no effect on the vasculopathy. Conversely, inhibition of VEGF-A activity attenuated vascular leak but did not protect photoreceptors. Our findings show that Müller glial deficiency may be an important upstream cause of retinal neuronal and vascular pathologies in retinal diseases. Combined neuroprotective and anti-angiogenic therapies may be required to treat Müller cell deficiency in retinal diseases and in other parts of the central nervous system associated with glial dysfunction. PMID:23136411

Glial cell adhesion and protein adsorption on SAM coated semiconductor and glass surfaces of a microfluidic structure

NASA Astrophysics Data System (ADS)

Sasaki, Darryl Y.; Cox, Jimmy D.; Follstaedt, Susan C.; Curry, Mark S.; Skirboll, Steven K.; Gourley, Paul L.

2001-05-01

The development of microsystems that merge biological materials with microfabricated structures is highly dependent on the successful interfacial interactions between these innately incompatible materials. Surface passivation of semiconductor and glass surfaces with thin organic films can attenuate the adhesion of proteins and cells that lead to biofilm formation and biofouling of fluidic structures. We have examined the adhesion of glial cells and serum albumin proteins to microfabricated glass and semiconductor surfaces coated with self-assembled monolayers of octadecyltrimethoxysilane and N-(triethoxysilylpropyl)-O- polyethylene oxide urethane, to evaluate the biocompatibility and surface passivation those coatings provide.

Vascular Endothelial Growth Factor in Eye Disease

PubMed Central

Penn, J.S.; Madan, A.; Caldwell, R.B.; Bartoli, M.; Caldwell, R.W.; Hartnett, M.E.

2012-01-01

Collectively, angiogenic ocular conditions represent the leading cause of irreversible vision loss in developed countries. In the U.S., for example, retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration are the principal causes of blindness in the infant, working age and elderly populations, respectively. Evidence suggests that vascular endothelial growth factor (VEGF), a 40 kDa dimeric glycoprotein, promotes angiogenesis in each of these conditions, making it a highly significant therapeutic target. However, VEGF is pleiotropic, affecting a broad spectrum of endothelial, neuronal and glial behaviors, and confounding the validity of anti-VEGF strategies, particularly under chronic disease conditions. In fact, among other functions VEGF can influence cell proliferation, cell migration, proteolysis, cell survival and vessel permeability in a wide variety of biological contexts. This article will describe the roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. The potential disadvantages of inhibiting VEGF will be discussed, as will the rationales for targeting other VEGF-related modulators of angiogenesis. PMID:18653375

Inhibition of hypoxia inducible factors combined with all-trans retinoic acid treatment enhances glial transdifferentiation of neuroblastoma cells.

PubMed

Cimmino, Flora; Pezone, Lucia; Avitabile, Marianna; Acierno, Giovanni; Andolfo, Immacolata; Capasso, Mario; Iolascon, Achille

2015-06-09

Neuroblastoma (NBL) is a heterogeneous tumor characterized by a wide range of clinical manifestations. A high tumor cell differentiation grade correlates to a favorable stage and positive outcome. Expression of the hypoxia inducible factors HIF1-α (HIF1A gene) and HIF2-α (EPAS1 gene) and/or hypoxia-regulated pathways has been shown to promote the undifferentiated phenotype of NBL cells. Our hypothesis is that HIF1A and EPAS1 expression represent one of the mechanisms responsible for the lack of responsiveness of NBL to differentiation therapy. Clinically, high levels of HIF1A and EPAS1 expression were associated with inferior survival in two NBL microarray datasets, and patient subgroups with lower expression of HIF1A and EPAS1 showed significant enrichment of pathways related to neuronal differentiation. In NBL cell lines, the combination of all-trans retinoic acid (ATRA) with HIF1A or EPAS1 silencing led to an acquired glial-cell phenotype and enhanced expression of glial-cell differentiation markers. Furthermore, HIF1A or EPAS1 silencing might promote cell senescence independent of ATRA treatment. Taken together, our data suggest that HIF inhibition coupled with ATRA treatment promotes differentiation into a more benign phenotype and cell senescence in vitro. These findings open the way for additional lines of attack in the treatment of NBL minimal residue disease.

Inhibition of hypoxia inducible factors combined with all-trans retinoic acid treatment enhances glial transdifferentiation of neuroblastoma cells

PubMed Central

Cimmino, Flora; Pezone, Lucia; Avitabile, Marianna; Acierno, Giovanni; Andolfo, Immacolata; Capasso, Mario; Iolascon, Achille

2015-01-01

Neuroblastoma (NBL) is a heterogeneous tumor characterized by a wide range of clinical manifestations. A high tumor cell differentiation grade correlates to a favorable stage and positive outcome. Expression of the hypoxia inducible factors HIF1-α (HIF1A gene) and HIF2-α (EPAS1 gene) and/or hypoxia-regulated pathways has been shown to promote the undifferentiated phenotype of NBL cells. Our hypothesis is that HIF1A and EPAS1 expression represent one of the mechanisms responsible for the lack of responsiveness of NBL to differentiation therapy. Clinically, high levels of HIF1A and EPAS1 expression were associated with inferior survival in two NBL microarray datasets, and patient subgroups with lower expression of HIF1A and EPAS1 showed significant enrichment of pathways related to neuronal differentiation. In NBL cell lines, the combination of all-trans retinoic acid (ATRA) with HIF1A or EPAS1 silencing led to an acquired glial-cell phenotype and enhanced expression of glial-cell differentiation markers. Furthermore, HIF1A or EPAS1 silencing might promote cell senescence independent of ATRA treatment. Taken together, our data suggest that HIF inhibition coupled with ATRA treatment promotes differentiation into a more benign phenotype and cell senescence in vitro. These findings open the way for additional lines of attack in the treatment of NBL minimal residue disease. PMID:26057707

Three-dimensional culture conditions differentially affect astrocyte modulation of brain endothelial barrier function in response to transforming growth factor β1.

PubMed

Hawkins, Brian T; Grego, Sonia; Sellgren, Katelyn L

2015-05-22

Blood-brain barrier (BBB) function is regulated by dynamic interactions among cell types within the neurovascular unit, including astrocytes and endothelial cells. Co-culture models of the BBB typically involve astrocytes seeded on two-dimensional (2D) surfaces, which recent studies indicate cause astrocytes to express a phenotype similar to that of reactive astrocytes in situ. We hypothesized that the culture conditions of astrocytes would differentially affect their ability to modulate BBB function in vitro. Brain endothelial cells were grown alone or in co-culture with astrocytes. Astrocytes were grown either as conventional (2D) monolayers, or in a collagen-based gel which allows them to grow in a three-dimensional (3D) construct. Astrocytes were viable in 3D conditions, and displayed a marked reduction in their expression of glial fibrillary acidic protein (GFAP), suggesting reduced activation. Stimulation of astrocytes with transforming growth factor (TGF)β1 decreased transendothelial electrical resistance (TEER) and reduced expression of claudin-5 in co-cultures, whereas treatment of endothelial cells in the absence of astrocytes was without effect. The effect of TGFβ1 on TEER was significantly more pronounced in endothelial cells cultured with 3D astrocytes compared to 2D astrocytes. These results demonstrate that astrocyte culture conditions differentially affect their ability to modulate brain endothelial barrier function, and suggest a direct relationship between reactive gliosis and BBB permeability. Moreover, these studies demonstrate the potential importance of physiologically relevant culture conditions to in vitro modeling of disease processes that affect the neurovascular unit. Copyright © 2015 Elsevier B.V. All rights reserved.

The gene coding for glial cell line derived neurotrophic factor (GDNF) maps to chromosome 5p12-p13.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schindelhauer, D.; Schuffenhauer, S.; Meitinger, T.

1995-08-10

The gene coding for glial cell line derived neurotrophic factor (GDNF) has biological properties that may have potential as a treatment for Parkinson`s and motoneuron diseases. Using the NIGMS Mapping Panel 2, we have localized the GDNF gene to human chromosome 5p12-p13.1. Large NruI and NotI fragments on chromosome 5 will facilitate the construction of a long-range map of the region. 26 refs., 1 fig., 1 tab.

Setting the Stage for Personalized Treatment of Glioma | Center for Cancer Research

Cancer.gov

Gliomas, the most common type of primary brain tumors in adults, arise from different types of glial cells, which support and protect the neurons of the central nervous system. How a patient’s glioma is treated depends in part on the type of glial cell from which the tumor developed. Classification of gliomas has traditionally been done by microscopic analysis of tumor sections. This process is subjective and prone to inconsistencies, which may explain in part the wide-ranging and often suboptimal responses of gliomas to treatment.  

Glio-vascular changes during ageing in wild-type and Alzheimer's disease-like APP/PS1 mice.

PubMed

Janota, C S; Brites, D; Lemere, C A; Brito, M A

2015-09-16

Vascular and glial involvement in the development of neurodegenerative disorders, such as Alzheimer's disease (AD), and age-related brain vulnerabilities have been suggested. Therefore, we sought to: (i) investigate which vascular and glial events are evident in ageing and/or AD, (ii) to establish the temporal evolution of vascular and glial changes in AD-like and wild-type (WT) mice and (iii) to relate them to amyloid-β (Aβ) peptide accumulation. We examined immunohistochemically hippocampi and cortex from APP/PS1dE9 and WT C57BL/6 mice along ageing and disease progression (young-adulthood, middle- and old-age). Ageing resulted in the increase in receptor for advanced glycation endproducts expression, as well as the entrance of thrombin and albumin in hippocampal parenchyma. In contrast, the loss of platelet-derived growth factor receptor-β (PDGFR-β) positive cells, in both regions, was only related to AD pathogenesis. Hypovascularization was affected by both ageing and AD in the hippocampus, but resulted from the interaction between both factors in the cortex. Astrogliosis was a result of AD in hippocampus and of both factors in cortex, while microgliosis was associated with fibrillar amyloid plaques in AD-like mice and with the interaction between both factors in each of the studied regions. In sum, these data show that senile plaques precede vascular and glial alterations only in hippocampus, whereas in cortex, vascular and glial alterations, namely the loss of PDGFR-β-positive cells and astrogliosis, accompanied the first senile plaques. Hence, this study points to vascular and glial events that co-exist in AD pathogenesis and age-related brain vulnerabilities. Copyright © 2015 Elsevier B.V. All rights reserved.

The use of glial data in human health assessments of environmental contaminants.

PubMed

Kraft, Andrew D

2015-07-03

Central nervous system (CNS) glia (i.e., astrocytes, microglia, and oligodendrocytes) are essential for maintaining neuronal homeostasis, and they orchestrate an organized cellular response to CNS injury. In addition to their beneficial roles, studies have demonstrated that disrupted glial function can have disastrous consequences on neuronal health. While effects on neuron-supportive glia are important to consider when evaluating neurotoxicity risk, interpreting glial changes is not always straightforward, particularly when attempting to discern pro-neurotoxic phenotypes from homeostatic processes or adaptive responses. To better understand how glia have been characterized and used in human health assessments of environmental contaminants (e.g., chemicals), an evaluation of all finalized assessments conducted by the U.S. Environmental Protection Agency's influential Integrated Risk Information System (IRIS) program between 1987 and 2013 was performed. Human health assessments to date have placed a clear emphasis on the neuronal cell response to potential toxicants, although more recent assessments increasingly include descriptions of glial changes. However, these descriptions are generally brief and non-specific, and they primarily consist of documenting gliosis following overt neuronal injury. As research interest in this topic continues to increase, methods for evaluating changes in glia continue to be expanded and refined, and assessors' confidence in the reliability of these data is likely to rise. Thus, glial data are anticipated to have an increasingly influential impact on the interpretation of neurotoxicity risk and underlying mechanisms. As our understanding of the complex roles these cells play grows, this knowledge is expected to support the inclusion of more extensive and specific descriptions of glial changes, including informed interpretations of the potential impact on CNS health, in future human health assessments. Published by Elsevier Ireland Ltd.

Hydrogen-rich saline protects retina against glutamate-induced excitotoxic injury in guinea pig.

PubMed

Wei, Lihua; Ge, Li; Qin, Shucun; Shi, Yunzhi; Du, Changqing; Du, Hui; Liu, Liwei; Yu, Yang; Sun, Xuejun

2012-01-01

Molecular hydrogen (H(2)) is an efficient antioxidant that can selectively reduce hydroxyl radicals and inhibit oxidative stress-induced injuries. We investigated the protective effects and mechanism of hydrogen-rich saline in a glutamate-induced retinal injury model. Retinal excitotoxicity was induced in healthy guinea pigs by injecting glutamate into the vitreous cavity. After 30 min, hydrogen-rich saline was injected into the vitreous cavity, the peritoneal cavity or both. Seven days later, the retinal stress response was evaluated by examining the stress biomarkers, inducible nitric-oxide synthase (iNOS) and glucose-regulated protein 78 (GRP78). The impaired glutamate uptake was assessed by the expression of the excitatory amino acid transporter 1(EAAT-1). The retinal histopathological changes were investigated, focusing on the thicknesses of the entire retina and its inner layer, the number of cells in the retinal ganglion cell layer (GCL) and the ultrastructure of the retinal ganglion cells (RGCs) and glial cells. Compared with the glutamate-induced injury group, the hydrogen-rich saline treatment reduced the loss of cells in the GCL and thinning of the retina and attenuated cellular morphological damage. These improvements were greatest in animals that received H(2) injections into both the vitreous and the peritoneal cavities. The hydrogen-rich saline also inhibited the expression of glial fibrillary acidic protein (GFAP) in Müller cells, CD11b in microglia, and iNOS and GRP78 in glial cells. Moreover, the hydrogen-rich saline increased the expression of EAAT-1. In conclusion, the administration of hydrogen-rich saline through the intravitreal or/and intraperitoneal routes could reduce the retinal excitotoxic injury and promote retinal recovery. This result likely occurs by inhibiting the activation of glial cells, decreasing the production of the iNOS and GRP78 and promoting glutamate clearance. Copyright © 2011 Elsevier Ltd. All rights reserved.

Chronic lead intoxication affects glial and neural systems and induces hypoactivity in adult rat.

PubMed

Sansar, Wafa; Ahboucha, Samir; Gamrani, Halima

2011-10-01

Lead is an environmental toxin and its effects are principally manifested in the brain. Glial and neuronal changes have been described during development following chronic or acute lead intoxication, however, little is known about the effects of chronic lead intoxication in adults. In this study we evaluated immunohistochemically the glial and dopaminergic systems in adult male Wistar rats. 0.5% (v/v) lead acetate in drinking water was administrated chronically over a 3-month period. Hypertrophic immunoreactive astrocytes were observed in the frontal cortex and other brain structures of the treated animals. Analysis of the astroglial features showed increased number of astrocyte cell bodies and processes in treated rats, an increase confirmed by Western blot. Particular distribution of glial fibrillary acidic protein immunoreactivity was observed within the blood vessel walls in which dense immunoreactive glial processes emanate from astrocytes. Glial changes in the frontal cortex were concomitant with reduced tyrosine hydroxylase immunoreactive neuronal processes, which seem to occur as a consequence of significantly reduced dopaminergic neurons within the nucleus of origin in the substantia nigra. These glial and neuronal changes following lead intoxication may affect animal behavior as evidenced by reduced locomotor activity in an open field test. These findings demonstrate that chronic lead exposure induces astroglial changes, which may compromise neuronal function and consequently animal behavior. Copyright © 2010 Elsevier GmbH. All rights reserved.

Three-dimensional slice cultures from murine fetal gut for investigations of the enteric nervous system.

PubMed

Metzger, Marco; Bareiss, Petra M; Nikolov, Ivan; Skutella, Thomas; Just, Lothar

2007-01-01

Three-dimensional intestinal cultures offer new possibilities for the examination of growth potential, analysis of time specific gene expression, and spatial cellular arrangement of enteric nervous system in an organotypical environment. We present an easy to produce in vitro model of the enteric nervous system for analysis and manipulation of cellular differentiation processes. Slice cultures of murine fetal colon were cultured on membrane inserts for up to 2 weeks without loss of autonomous contractility. After slice preparation, cultured tissue reorganized within the first days in vitro. Afterward, the culture possessed more than 35 cell layers, including high prismatic epithelial cells, smooth muscle cells, glial cells, and neurons analyzed by immunohistochemistry. The contraction frequency of intestinal slice culture could be modulated by the neurotransmitter serotonin and the sodium channel blocker tetrodotoxin. Coculture experiments with cultured neurospheres isolated from enhanced green fluorescent protein (eGFP) transgenic mice demonstrated that differentiating eGFP-positive neurons were integrated into the intestinal tissue culture. This slice culture model of enteric nervous system proved to be useful for studying cell-cell interactions, cellular signaling, and cell differentiation processes in a three-dimensional cell arrangement.

Evidence for a Role of Connexin 43 in Trigeminal Pain Using RNA Interference In Vivo

PubMed Central

Ohara, Peter T.; Vit, Jean-Philippe; Bhargava, Aditi; Jasmin, Luc

2008-01-01

The importance of glial cells in the generation and maintenance of neuropathic pain is becoming widely accepted. We examined the role of glial-specific gap junctions in nociception in the rat trigeminal ganglion in nerve-injured and -uninjured states. The connexin 43 (Cx43) gap-junction subunit was found to be confined to the satellite glial cells (SGCs) that tightly envelop primary sensory neurons in the trigeminal ganglion and we therefore used Cx43 RNA interference (RNAi) to alter gap-junction function in SGCs. Using behavioral evaluation, together with immunocytochemical and Western blot monitoring, we show that Cx43 increased in the trigeminal ganglion in rats with a chronic constriction injury (CCI) of the infraorbital nerve. Reducing Cx43 expression using RNAi in CCI rats reduced painlike behavior, whereas in non-CCI rats, reducing Cx43 expression increased painlike behavior. The degree of painlike behavior in CCI rats and intact, Cx43-silenced rats was similar. Our results support previous suggestions that increases in glial gap junctions after nerve injury increases nociceptive behavior but paradoxically the reduction of gap junctions in normal ganglia also increases nociceptive behavior, possibly a reflection of the multiple functions performed by glia. PMID:18715894

Low-dose/dose-rate γ radiation depresses neural differentiation and alters protein expression profiles in neuroblastoma SH-SY5Y cells and C17.2 neural stem cells.

PubMed

Bajinskis, Ainars; Lindegren, Heléne; Johansson, Lotta; Harms-Ringdahl, Mats; Forsby, Anna

2011-02-01

The effects of low doses of ionizing radiation on cellular development in the nervous system are presently unclear. The focus of the present study was to examine low-dose γ-radiation-induced effects on the differentiation of neuronal cells and on the development of neural stem cells to glial cells. Human neuroblastoma SH-SY5Y cells were exposed to (137)Cs γ rays at different stages of retinoic acid-induced neuronal differentiation, and neurite formation was determined 6 days after exposure. When SH-SY5Y cells were exposed to low-dose-rate γ rays at the onset of differentiation, the number of neurites formed per cell was significantly less after exposure to either 10, 30 or 100 mGy compared to control cells. Exposure to 10 and 30 mGy attenuated differentiation of immature C17.2 mouse-derived neural stem cells to glial cells, as verified by the diminished expression of glial fibrillary acidic protein. Proteomic analysis of the neuroblastoma cells by 2D-PAGE after 30 mGy irradiation showed that proteins involved in neuronal development were downregulated. Proteins involved in cell cycle and proliferation were altered in both cell lines after exposure to 30 mGy; however, the rate of cell proliferation was not affected in the low-dose range. The radiation-induced attenuation of differentiation and the persistent changes in protein expression is indicative of an epigenetic rather than a cytotoxic mechanism.

ATPergic signalling during seizures and epilepsy.

PubMed

Engel, Tobias; Alves, Mariana; Sheedy, Caroline; Henshall, David C

2016-05-01

Much progress has been made over the last few decades in the identification of new anti-epileptic drugs (AEDs). However, 30% of epilepsy patients suffer poor seizure control. This underscores the need to identify alternative druggable neurotransmitter systems and drugs with novel mechanisms of action. An emerging concept is that seizure generation involves a complex interplay between neurons and glial cells at the tripartite synapse and neuroinflammation has been proposed as one of the main drivers of epileptogenesis. The ATP-gated purinergic receptor family is expressed throughout the brain and is functional on neurons and glial cells. ATP is released in high amounts into the extracellular space after increased neuronal activity and during chronic inflammation and cell death to act as a neuro- and gliotransmitter. Emerging work shows pharmacological targeting of ATP-gated purinergic P2 receptors can potently modulate seizure generation, inflammatory processes and seizure-induced brain damage. To date, work showing the functional contribution of P2 receptors has been mainly performed in animal models of acute seizures, in particular, by targeting the ionotropic P2X7 receptor subtype. Other ionotropic P2X and metabotropic P2Y receptor family members have also been implicated in pathological processes following seizures such as the P2X4 receptor and the P2Y12 receptor. However, during epilepsy, the characterization of P2 receptors was mostly restricted to the study of expressional changes of the different receptor subtypes. This review summarizes the work to date on ATP-mediated signalling during seizures and the functional impact of targeting the ATP-gated purinergic receptors on seizures and seizure-induced pathology. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polyurethane/polylactide-based biomaterials combined with rat olfactory bulb-derived glial cells and adipose-derived mesenchymal stromal cells for neural regenerative medicine applications.

PubMed

Grzesiak, Jakub; Marycz, Krzysztof; Szarek, Dariusz; Bednarz, Paulina; Laska, Jadwiga

2015-01-01

Research concerning the elaboration and application of biomaterial which may support the nerve tissue regeneration is currently one of the most promising directions. Biocompatible polymer devices are noteworthy group among the numerous types of potentially attractive biomaterials for regenerative medicine application. Polylactides and polyurethanes may be utilized for developing devices for supporting the nerve regeneration, like nerve guide conduits or bridges connecting the endings of broken nerve tracts. Moreover, the combination of these biomaterial devices with regenerative cell populations, like stem or precursor cells should significantly improve the final therapeutic effect. Therefore, the composition and structure of final device should support the proper adhesion and growth of cells destined for clinical application. In current research, the three polymer mats elaborated for connecting the broken nerve tracts, made from polylactide, polyurethane and their blend were evaluated both for physical properties and in vitro, using the olfactory-bulb glial cells and mesenchymal stem cells. The evaluation of Young's modulus, wettability and roughness of obtained materials showed the differences between analyzed samples. The analysis of cell adhesion, proliferation and morphology showed that the polyurethane-polylactide blend was the most neutral for cells in culture, while in the pure polymer samples there were significant alterations observed. Our results indicated that polyurethane-polylactide blend is an optimal composition for culturing and delivery of glial and mesenchymal stem cells. Copyright © 2015. Published by Elsevier B.V.

Magnolol protects against trimethyltin-induced neuronal damage and glial activation in vitro and in vivo.

PubMed

Kim, Da Jung; Kim, Yong Sik

2016-03-01

Trimethyltin (TMT), an organotin with potent neurotoxic effects by selectively damaging to hippocampus, is used as a tool for creating an experimental model of neurodegeneration. In the present study, we investigated the protective effects of magnolol, a natural biphenolic compound, on TMT-induced neurodegeneration and glial activation in vitro and in vivo. In HT22 murine neuroblastoma cells, TMT induced necrotic/apoptotic cell death and oxidative stress, including intracellular reactive oxygen species (ROS), protein carbonylation, induction of heme oxygenase-1 (HO-1), and activation of all mitogen-activated protein kinases (MAPKs) family proteins. However, magnolol treatment significantly suppressed neuronal cell death by inhibiting TMT-mediated ROS generation and activation of JNK and p38 MAPKs. In BV-2 microglial cells, magnolol efficiently attenuated TMT-induced microglial activation via suppression of ROS generation and activation of JNK, p38 MAPKs, and nuclear factor-κB (NF-κB) signaling. In an in vivo mouse study, TMT induced massive neuronal damage and enhanced oxidative stress at day 2. We also observed a concomitant increase in glial cells and inducible nitric oxide synthase (iNOS) expression on the same day. These features of TMT toxicity were reversed by treatment of magnolol. We observed that p-JNK and p-p38 MAPK levels were increased in the mouse hippocampus at day 1 after TMT treatment and that magnolol blocked TMT-induced JNK and p38 MAPK activation. Magnolol administration prevented TMT-induced hippocampal neurodegeneration and glial activation, possibly through the regulation of TMT-mediated ROS generation and MAPK activation. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Calcium alters monoamine oxidase-A parameters in human cerebellar and rat glial C6 cell extracts: possible influence by distinct signalling pathways.

PubMed

Cao, Xia; Li, Xin-Min; Mousseau, Darrell D

2009-07-31

Calcium (Ca(2+)) is known to augment monoamine oxidase-A (MAO-A) activity in cell cultures as well as in brain extracts from several species. This association between Ca(2+) and MAO-A could contribute to their respective roles in cytotoxicity. However, the effect of Ca(2+) on MAO-A function in human brain has as yet to be examined as does the contribution of specific signalling cascades. We examined the effects of Ca(2+) on MAO-A activity and on [(3)H]Ro 41-1049 binding to MAO-A in human cerebellar extracts, and compared this to its effects on MAO-A activity in glial C6 cells following the targeting of signalling pathways using specific chemical inhibitors. Ca(2+) enhances MAO-A activity as well as the association of [(3)H]Ro 41-1049 to MAO-A in human cerebellar extracts. The screening of neuronal and glial cell cultures reveals that MAO-A activity does not always correlate with the expression of either mao-A mRNA or MAO-A protein. Inhibition of the individual PI3K/Akt, ERK and p38(MAPK) signalling pathways in glial C6 cells all augment basal MAO-A activity. Inhibition of the p38(MAPK) pathway also augments Ca(2+)-sensitive MAO-A activity. We also observe the inverse relation between p38(MAPK) activation and MAO-A function in C6 cultures grown to full confluence. The Ca(2+)-sensitive component to MAO-A activity is present in human brain and in vitro studies link it to the p38(MAPK) pathway. This means of influencing MAO-A function could explain its role in pathologies as diverse as neurodegeneration and cancers.

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

Calcineurin A beta deficiency ameliorates HFD-induced hypothalamic astrocytosis in mice.

PubMed

Pfuhlmann, Katrin; Schriever, Sonja C; Legutko, Beata; Baumann, Peter; Harrison, Luke; Kabra, Dhiraj G; Baumgart, Emily Violette; Tschöp, Matthias H; Garcia-Caceres, Cristina; Pfluger, Paul T

2018-02-08

ᅟ: Astrocytosis is a reactive process involving cellular, molecular, and functional changes to facilitate neuronal survival, myelin preservation, blood brain barrier function and protective glial scar formation upon brain insult. The overall pro- or anti-inflammatory impact of reactive astrocytes appears to be driven in a context- and disease-driven manner by modulation of astrocytic Ca 2+ homeostasis and activation of Ca 2+ /calmodulin-activated serine/threonine phosphatase calcineurin. Here, we aimed to assess whether calcineurin is dispensable for astrocytosis in the hypothalamus driven by prolonged high fat diet (HFD) feeding. Global deletion of calcineurin A beta (gene name: Ppp3cb) led to a decrease of glial fibrillary acidic protein (GFAP)-positive cells in the ventromedial hypothalamus (VMH), dorsomedial hypothalamus (DMH), and arcuate nucleus (ARC) of mice exposed chronically to HFD. The concomitant decrease in Iba1-positive microglia in the VMH further suggests a modest impact of Ppp3cb deletion on microgliosis. Pharmacological inhibition of calcineurin activity by Fk506 had no impact on IBA1-positive microglia in hypothalami of mice acutely exposed to HFD for 1 week. However, Fk506-treated mice displayed a decrease in GFAP levels in the ARC. In vivo effects could not be replicated in cell culture, where calcineurin inhibition by Fk506 had no effect on astrocytic morphology, astrocytic cell death, GFAP, and vimentin protein levels or microglia numbers in primary hypothalamic astrocytes and microglia co-cultures. Further, adenoviral overexpression of calcineurin subunit Ppp3r1 in primary glia culture did not lead to an increase in GFAP fluorescence intensity. Overall, our results point to a prominent role of calcineurin in mediating hypothalamic astrocytosis as response to acute and chronic HFD exposure. Moreover, discrepant findings in vivo and in cell culture indicate the necessity of studying astrocytes in their "natural" environment, i.e., preserving an intact hypothalamic microenvironment with neurons and non-neuronal cells in close proximity.

A novel enteric neuron-glia coculture system reveals the role of glia in neuronal development.

PubMed

Le Berre-Scoul, Catherine; Chevalier, Julien; Oleynikova, Elena; Cossais, François; Talon, Sophie; Neunlist, Michel; Boudin, Hélène

2017-01-15

Unlike astrocytes in the brain, the potential role of enteric glial cells (EGCs) in the formation of the enteric neuronal circuit is currently unknown. To examine the role of EGCs in the formation of the neuronal network, we developed a novel neuron-enriched culture model from embryonic rat intestine grown in indirect coculture with EGCs. We found that EGCs shape axonal complexity and synapse density in enteric neurons, through purinergic- and glial cell line-derived neurotrophic factor-dependent pathways. Using a novel and valuable culture model to study enteric neuron-glia interactions, our study identified EGCs as a key cellular actor regulating neuronal network maturation. In the nervous system, the formation of neuronal circuitry results from a complex and coordinated action of intrinsic and extrinsic factors. In the CNS, extrinsic mediators derived from astrocytes have been shown to play a key role in neuronal maturation, including dendritic shaping, axon guidance and synaptogenesis. In the enteric nervous system (ENS), the potential role of enteric glial cells (EGCs) in the maturation of developing enteric neuronal circuit is currently unknown. A major obstacle in addressing this question is the difficulty in obtaining a valuable experimental model in which enteric neurons could be isolated and maintained without EGCs. We adapted a cell culture method previously developed for CNS neurons to establish a neuron-enriched primary culture from embryonic rat intestine which was cultured in indirect coculture with EGCs. We demonstrated that enteric neurons grown in such conditions showed several structural, phenotypic and functional hallmarks of proper development and maturation. However, when neurons were grown without EGCs, the complexity of the axonal arbour and the density of synapses were markedly reduced, suggesting that glial-derived factors contribute strongly to the formation of the neuronal circuitry. We found that these effects played by EGCs were mediated in part through purinergic P2Y 1 receptor- and glial cell line-derived neurotrophic factor-dependent pathways. Using a novel and valuable culture model to study enteric neuron-glia interactions, our study identified EGCs as a key cellular actor required for neuronal network maturation. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The CD59 family member Leaky/Coiled is required for the establishment of the blood-brain barrier in Drosophila.

PubMed

Syed, Mubarak Hussain; Krudewig, Alice; Engelen, Daniel; Stork, Tobias; Klämbt, Christian

2011-05-25

The blood-brain barrier of Drosophila is established by the subperineurial glial cells that encase the CNS and PNS. The subperineurial glial cells are thin, highly interdigitated cells with epithelial character. The establishment of extensive septate junctions between these cells is crucial for the prevention of uncontrolled paracellular leakage of ions and solutes from the hemolymph into the nervous system. In the absence of septate junctions, macromolecules such as fluorescently labeled dextran can easily cross the blood-brain barrier. To identify additional components of the blood-brain barrier, we followed a genetic approach and injected Texas-Red-conjugated dextran into the hemolymph of embryos homozygous for chromosomal deficiencies. In this way, we identified the 153-aa-large protein Coiled, a new member of the Ly6 (leukocyte antigen 6) family, as being crucially required for septate junction formation and blood-brain barrier integrity. In coiled mutants, the normal distribution of septate junction markers such as NeurexinIV, Coracle, or Discs large is disturbed. EM analyses demonstrated that Coiled is required for the formation of septate junctions. We further show that Coiled is expressed by the subsperineurial glial cells in which it is anchored to the cell membrane via a glycosylphosphatidylinositol anchor and mediates adhesive properties. Clonal rescue studies indicate that the presence of Coiled is required symmetrically on both cells engaged in septate junction formation.

Substance P receptor binding sites are expressed by glia in vivo after neuronal injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mantyh, P.W.; Johnson, D.J.; Boehmer, C.G.

1989-07-01

In vitro studies have demonstrated that glia can express functional receptors for a variety of neurotransmitters. To determine whether similar neurotransmitter receptors are also expressed by glia in vivo, the authors examined the glial scar in the transected optic nerve of the albino rabbit by quantitative receptor autoradiography. Receptor binding sites for radiolabeled calcitonin gene-related peptide, cholecystokinin, galanin, glutamate, somatostatin, substance P, and vasoactive intestinal peptide were examined. Specific receptor binding sites for each of these neurotransmitters were identified in the rabbit forebrain but were not detected in the normal optic nerve or tract. In the transected optic nerve andmore » tract, only receptor binding sites for substance P were expressed at detectable levels. The density of substance P receptor binding sites observed in this glial scar is among the highest observed in the rabbit forebrain. Ligand displacement and saturation experiments indicate that the substance P receptor binding site expressed by the glial scar has pharmacological characteristics similar to those of substance P receptors in the rabbit striatum, rat brain, and rat and canine gut. The present study demonstrates that glial cells in vivo express high concentrations of substance P receptor binding sites after transection of retinal ganglion cell axons. Because substance P has been shown to regulate inflammatory and immune responses in peripheral tissues, substance P may also, by analogy, be involved in regulating the glial response to injury in the central nervous system.« less

[Expression of vimentin and GFAP and development of the retina in the trout].

PubMed

De Guevara, R; Pairault, C; Pinganaud, G

1994-08-01

The glial cell development was studied during the edification of the retina and the optic tract, in a teleost, the rainbow trout. The intermediate filament proteins, vimentin and glial fibrillary acidic protein (GFAP) were visualized by an indirect immunohistochemical method. Results show that both vimentin and GFAP are early expressed in the developing retina and, particularly in the Müller cells, a coexpression of vimentin and GFAP is observed from embryonic to adult stages. The ganglion cell layer and the optic fiber layer both exhibit GFAP-positive structures. The deep staining for GFAP is also seen in the optic nerve and induces us to credit astrocyte-like cells with a leading role in the pattern formation of this tract.

Ascl1 controls the number and distribution of astrocytes and oligodendrocytes in the gray matter and white matter of the spinal cord

PubMed Central

Vue, Tou Yia; Kim, Euiseok J.; Parras, Carlos M.; Guillemot, Francois; Johnson, Jane E.

2014-01-01

Glia constitute the majority of cells in the mammalian central nervous system and are crucial for neurological function. However, there is an incomplete understanding of the molecular control of glial cell development. We find that the transcription factor Ascl1 (Mash1), which is best known for its role in neurogenesis, also functions in both astrocyte and oligodendrocyte lineages arising in the mouse spinal cord at late embryonic stages. Clonal fate mapping in vivo reveals heterogeneity in Ascl1-expressing glial progenitors and shows that Ascl1 defines cells that are restricted to either gray matter (GM) or white matter (WM) as astrocytes or oligodendrocytes. Conditional deletion of Ascl1 post-neurogenesis shows that Ascl1 is required during oligodendrogenesis for generating the correct numbers of WM but not GM oligodendrocyte precursor cells, whereas during astrocytogenesis Ascl1 functions in balancing the number of dorsal GM protoplasmic astrocytes with dorsal WM fibrous astrocytes. Thus, in addition to its function in neurogenesis, Ascl1 marks glial progenitors and controls the number and distribution of astrocytes and oligodendrocytes in the GM and WM of the spinal cord. PMID:25249462

Effect of chronic antipsychotic exposure on astrocyte and oligodendrocyte numbers in macaque monkeys

PubMed Central

Konopaske, Glenn T.; Dorph-Petersen, Karl-Anton; Sweet, Robert A.; Pierri, Joseph N.; Zhang, Wei; Sampson, Allan R.; Lewis, David A.

2008-01-01

Background Both in vivo and post-mortem studies suggest that oligodendrocyte and myelination alterations are present in individuals with schizophrenia. However, it is unclear whether prolonged treatment with antipsychotic medications contributes to these disturbances. We recently reported that chronic exposure of macaque monkeys to haloperidol or olanzapine was associated with a 10−18% lower glial cell number in the parietal grey matter. Consequently, in this study we sought to determine whether the lower glial cell number was due to fewer oligodendrocytes as opposed to lower numbers of astrocytes. Methods Using fluorescent immunocytochemical techniques, we optimized the visualization of each cell type throughout the entire thickness of tissue sections, while minimizing final tissue shrinkage. As a result, we were able to obtain robust stereological estimates of total oligodendrocyte and astrocyte numbers in the parietal grey matter using the optical fractionator method. Results We found a significant 20.5% lower astrocyte number with a non-significant 12.9% lower oligodendrocyte number in the antipsychotic-exposed monkeys. Similar effects were seen in both the haloperidol and olanzapine groups. Conclusion These findings suggest that studies investigating glial cell alterations in schizophrenia must take into account the effect of antipsychotic treatment. PMID:17945195

Effects of Flavonoids from Food and Dietary Supplements on Glial and Glioblastoma Multiforme Cells.

PubMed

Vidak, Marko; Rozman, Damjana; Komel, Radovan

2015-10-23

Quercetin, catechins and proanthocyanidins are flavonoids that are prominently featured in foodstuffs and dietary supplements, and may possess anti-carcinogenic activity. Glioblastoma multiforme is the most dangerous form of glioma, a malignancy of the brain connective tissue. This review assesses molecular structures of these flavonoids, their importance as components of diet and dietary supplements, their bioavailability and ability to cross the blood-brain barrier, their reported beneficial health effects, and their effects on non-malignant glial as well as glioblastoma tumor cells. The reviewed flavonoids appear to protect glial cells via reduction of oxidative stress, while some also attenuate glutamate-induced excitotoxicity and reduce neuroinflammation. Most of the reviewed flavonoids inhibit proliferation of glioblastoma cells and induce their death. Moreover, some of them inhibit pro-oncogene signaling pathways and intensify the effect of conventional anti-cancer therapies. However, most of these anti-glioblastoma effects have only been observed in vitro or in animal models. Due to limited ability of the reviewed flavonoids to access the brain, their normal dietary intake is likely insufficient to produce significant anti-cancer effects in this organ, and supplementation is needed.

Characterization of Panglial Gap Junction Networks in the Thalamus, Neocortex, and Hippocampus Reveals a Unique Population of Glial Cells

PubMed Central

Griemsmann, Stephanie; Höft, Simon P.; Bedner, Peter; Zhang, Jiong; von Staden, Elena; Beinhauer, Anna; Degen, Joachim; Dublin, Pavel; Cope, David W.; Richter, Nadine; Crunelli, Vincenzo; Jabs, Ronald; Willecke, Klaus; Theis, Martin; Seifert, Gerald; Kettenmann, Helmut; Steinhäuser, Christian

2015-01-01

The thalamus plays important roles as a relay station for sensory information in the central nervous system (CNS). Although thalamic glial cells participate in this activity, little is known about their properties. In this study, we characterized the formation of coupled networks between astrocytes and oligodendrocytes in the murine ventrobasal thalamus and compared these properties with those in the hippocampus and cortex. Biocytin filling of individual astrocytes or oligodendrocytes revealed large panglial networks in all 3 gray matter regions. Combined analyses of mice with cell type-specific deletion of connexins (Cxs), semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and western blotting showed that Cx30 is the dominant astrocytic Cx in the thalamus. Many thalamic astrocytes even lack expression of Cx43, while in the hippocampus astrocytic coupling is dominated by Cx43. Deletion of Cx30 and Cx47 led to complete loss of panglial coupling, which was restored when one allele of either Cxs was present. Immunohistochemistry revealed a unique antigen profile of thalamic glia and identified an intermediate cell type expressing both Olig2 and Cx43. Our findings further the emerging concept of glial heterogeneity across brain regions. PMID:25037920

Müller Glial Cell-Provided Cellular Light Guidance through the Vital Guinea-Pig Retina

PubMed Central

Agte, Silke; Junek, Stephan; Matthias, Sabrina; Ulbricht, Elke; Erdmann, Ines; Wurm, Antje; Schild, Detlev; Käs, Josef A.; Reichenbach, Andreas

2011-01-01

In vertebrate eyes, images are projected onto an inverted retina where light passes all retinal layers on its way to the photoreceptor cells. Light scattering within this tissue should impair vision. We show that radial glial (Müller) cells in the living retina minimize intraretinal light scatter and conserve the diameter of a beam that hits a single Müller cell endfoot. Thus, light arrives at individual photoreceptors with high intensity. This leads to an optimized signal/noise ratio, which increases visual sensitivity and contrast. Moreover, we show that the ratio between Müller cells and cones—responsible for acute vision—is roughly 1. This suggests that high spatiotemporal resolution may be achieved by each cone receiving its part of the image via its individual Müller cell-light guide. PMID:22261048

Transcriptional differences between normal and glioma-derived glial progenitor cells identify a core set of dysregulated genes.

PubMed

Auvergne, Romane M; Sim, Fraser J; Wang, Su; Chandler-Militello, Devin; Burch, Jaclyn; Al Fanek, Yazan; Davis, Danielle; Benraiss, Abdellatif; Walter, Kevin; Achanta, Pragathi; Johnson, Mahlon; Quinones-Hinojosa, Alfredo; Natesan, Sridaran; Ford, Heide L; Goldman, Steven A

2013-06-27

Glial progenitor cells (GPCs) are a potential source of malignant gliomas. We used A2B5-based sorting to extract tumorigenic GPCs from human gliomas spanning World Health Organization grades II-IV. Messenger RNA profiling identified a cohort of genes that distinguished A2B5+ glioma tumor progenitor cells (TPCs) from A2B5+ GPCs isolated from normal white matter. A core set of genes and pathways was substantially dysregulated in A2B5+ TPCs, which included the transcription factor SIX1 and its principal cofactors, EYA1 and DACH2. Small hairpin RNAi silencing of SIX1 inhibited the expansion of glioma TPCs in vitro and in vivo, suggesting a critical and unrecognized role of the SIX1-EYA1-DACH2 system in glioma genesis or progression. By comparing the expression patterns of glioma TPCs with those of normal GPCs, we have identified a discrete set of pathways by which glial tumorigenesis may be better understood and more specifically targeted. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Lipid metabolism in myelinating glial cells: lessons from human inherited disorders and mouse models.

PubMed

Chrast, Roman; Saher, Gesine; Nave, Klaus-Armin; Verheijen, Mark H G

2011-03-01

The integrity of central and peripheral nervous system myelin is affected in numerous lipid metabolism disorders. This vulnerability was so far mostly attributed to the extraordinarily high level of lipid synthesis that is required for the formation of myelin, and to the relative autonomy in lipid synthesis of myelinating glial cells because of blood barriers shielding the nervous system from circulating lipids. Recent insights from analysis of inherited lipid disorders, especially those with prevailing lipid depletion and from mouse models with glia-specific disruption of lipid metabolism, shed new light on this issue. The particular lipid composition of myelin, the transport of lipid-associated myelin proteins, and the necessity for timely assembly of the myelin sheath all contribute to the observed vulnerability of myelin to perturbed lipid metabolism. Furthermore, the uptake of external lipids may also play a role in the formation of myelin membranes. In addition to an improved understanding of basic myelin biology, these data provide a foundation for future therapeutic interventions aiming at preserving glial cell integrity in metabolic disorders.

Lipid metabolism in myelinating glial cells: lessons from human inherited disorders and mouse models

PubMed Central

Chrast, Roman; Saher, Gesine; Nave, Klaus-Armin; Verheijen, Mark H. G.

2011-01-01

The integrity of central and peripheral nervous system myelin is affected in numerous lipid metabolism disorders. This vulnerability was so far mostly attributed to the extraordinarily high level of lipid synthesis that is required for the formation of myelin, and to the relative autonomy in lipid synthesis of myelinating glial cells because of blood barriers shielding the nervous system from circulating lipids. Recent insights from analysis of inherited lipid disorders, especially those with prevailing lipid depletion and from mouse models with glia-specific disruption of lipid metabolism, shed new light on this issue. The particular lipid composition of myelin, the transport of lipid-associated myelin proteins, and the necessity for timely assembly of the myelin sheath all contribute to the observed vulnerability of myelin to perturbed lipid metabolism. Furthermore, the uptake of external lipids may also play a role in the formation of myelin membranes. In addition to an improved understanding of basic myelin biology, these data provide a foundation for future therapeutic interventions aiming at preserving glial cell integrity in metabolic disorders. PMID:21062955

RNCR3 knockdown inhibits diabetes mellitus-induced retinal reactive gliosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chang; Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai; The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing

Retinal reactive gliosis is an important pathological feature of diabetic retinopathy. Identifying the underlying mechanisms causing reactive gliosis will be important for developing new therapeutic strategies for treating diabetic retinopathy. Herein, we show that long noncoding RNA-RNCR3 knockdown significantly inhibits retinal reactive gliosis. RNCR3 knockdown leads to a marked reduction in the release of several cytokines. RNCR3 knockdown alleviates diabetes mellitus-induced retinal neurodegeneration, as shown by less apoptotic retinal cells and ameliorative visual function. RNCR3 knockdown could also decrease Müller glial cell viability and proliferation, and reduce the expression of glial reactivity-related genes including GFAP and vimentin in vitro. Collectively, thismore » study shows that RNCR3 knockdown may be a promising strategy for the prevention of diabetes mellitus-induced retinal neurodegeneration. - Highlights: • RNCR3 knockdown inhibits retinal reactive gliosis. • RNCR3 knockdown causes a significant change in cytokine profile. • RNCR3 knockdown alleviates diabetes mellitus-induced retinal neurodegeneration. • RNCR3 knockdown affects Müller glial cell function in vitro.« less

MCT2 Expression and Lactate Influx in Anorexigenic and Orexigenic Neurons of the Arcuate Nucleus

PubMed Central

Cortes-Campos, Christian; Elizondo, Roberto; Carril, Claudio; Martínez, Fernando; Boric, Katica; Nualart, Francisco; Garcia-Robles, Maria Angeles

2013-01-01

Hypothalamic neurons of the arcuate nucleus control food intake, releasing orexigenic and anorexigenic neuropeptides in response to changes in glucose concentration. Several studies have suggested that the glucosensing mechanism is governed by a metabolic interaction between neurons and glial cells via lactate flux through monocarboxylate transporters (MCTs). Hypothalamic glial cells (tanycytes) release lactate through MCT1 and MCT4; however, similar analyses in neuroendocrine neurons have yet to be undertaken. Using primary rat hypothalamic cell cultures and fluorimetric assays, lactate incorporation was detected. Furthermore, the expression and function of MCT2 was demonstrated in the hypothalamic neuronal cell line, GT1-7, using kinetic and inhibition assays. Moreover, MCT2 expression and localization in the Sprague Dawley rat hypothalamus was analyzed using RT-PCR, in situ hybridization and Western blot analyses. Confocal immunohistochemistry analyses revealed MCT2 localization in neuronal but not glial cells. Moreover, MCT2 was localized to ∼90% of orexigenic and ∼60% of anorexigenic neurons as determined by immunolocalization analysis of AgRP and POMC with MCT2-positives neurons. Thus, MCT2 distribution coupled with lactate uptake by hypothalamic neurons suggests that hypothalamic neurons control food intake using lactate to reflect changes in glucose levels. PMID:23638108

Conditional Müllercell ablation causes independent neuronal and vascular pathologies in a novel transgenic model.

PubMed

Shen, Weiyong; Fruttiger, Marcus; Zhu, Ling; Chung, Sook H; Barnett, Nigel L; Kirk, Joshua K; Lee, SoRa; Coorey, Nathan J; Killingsworth, Murray; Sherman, Larry S; Gillies, Mark C

2012-11-07

Müller cells are the major glia of the retina that serve numerous functions essential to retinal homeostasis, yet the contribution of Müller glial dysfunction to retinal diseases remains largely unknown. We have developed a transgenic model using a portion of the regulatory region of the retinaldehyde binding protein 1 gene for conditional Müller cell ablation and the consequences of primary Müller cell dysfunction have been studied in adult mice. We found that selective ablation of Müller cells led to photoreceptor apoptosis, vascular telangiectasis, blood-retinal barrier breakdown and, later, intraretinal neovascularization. These changes were accompanied by impaired retinal function and an imbalance between vascular endothelial growth factor-A (VEGF-A) and pigment epithelium-derived factor. Intravitreal injection of ciliary neurotrophic factor inhibited photoreceptor injury but had no effect on the vasculopathy. Conversely, inhibition of VEGF-A activity attenuated vascular leak but did not protect photoreceptors. Our findings show that Müller glial deficiency may be an important upstream cause of retinal neuronal and vascular pathologies in retinal diseases. Combined neuroprotective and anti-angiogenic therapies may be required to treat Müller cell deficiency in retinal diseases and in other parts of the CNS associated with glial dysfunction.

Brain-Immune Interactions as the Basis of Gulf War Illness: Gulf War Illness Consortium (GWIC)

DTIC Science & Technology

2014-10-01

neuroinflammation as an end result of initial glial activation and subsequent priming of glial responses that cause a chronic activation loop of...infection, or physical trauma—that mobilizes CNS defense systems via activation of glia, the brain’s primary immune response cells, and release of...oligodendrocytes Microglial Activation (cytokine signaling) Behavioral Effects (fatigue, pain, cognitive problems) Astrocyte Activation (cytokine signaling

The signaling role for chloride in the bidirectional communication between neurons and astrocytes.

PubMed

Wilson, Corinne S; Mongin, Alexander A

2018-01-09

It is well known that the electrical signaling in neuronal networks is modulated by chloride (Cl - ) fluxes via the inhibitory GABA A and glycine receptors. Here, we discuss the putative contribution of Cl - fluxes and intracellular Cl - to other forms of information transfer in the CNS, namely the bidirectional communication between neurons and astrocytes. The manuscript (i) summarizes the generic functions of Cl - in cellular physiology, (ii) recaps molecular identities and properties of Cl - transporters and channels in neurons and astrocytes, and (iii) analyzes emerging studies implicating Cl - in the modulation of neuroglial communication. The existing literature suggests that neurons can alter astrocytic Cl - levels in a number of ways; via (a) the release of neurotransmitters and activation of glial transporters that have intrinsic Cl - conductance, (b) the metabotropic receptor-driven changes in activity of the electroneutral cation-Cl - cotransporter NKCC1, and (c) the transient, activity-dependent changes in glial cell volume which open the volume-regulated Cl - /anion channel VRAC. Reciprocally, astrocytes are thought to alter neuronal [Cl - ] i through either (a) VRAC-mediated release of the inhibitory gliotransmitters, GABA and taurine, which open neuronal GABA A and glycine receptor/Cl - channels, or (b) the gliotransmitter-driven stimulation of NKCC1. The most important recent developments in this area are the identification of the molecular composition and functional heterogeneity of brain VRAC channels, and the discovery of a new cytosolic [Cl - ] sensor - the Wnk family protein kinases. With new work in the field, our understanding of the role of Cl - in information processing within the CNS is expected to be significantly updated. Copyright © 2018 Elsevier B.V. All rights reserved.

The Selective Glucocorticoid Receptor Modulator Cort 113176 Reduces Neurodegeneration and Neuroinflammation in Wobbler Mice Spinal Cord.

PubMed

Meyer, Maria; Lara, Agustina; Hunt, Hazel; Belanoff, Joseph; de Kloet, E Ronald; Gonzalez Deniselle, Maria Claudia; De Nicola, Alejandro F

2018-06-08

Wobbler mice are experimental models for amyotrophic lateral sclerosis. As such they show motoneuron degeneration, motor deficits, and astrogliosis and microgliosis of the spinal cord. Additionally, Wobbler mice show increased plasma, spinal cord and brain corticosterone levels and focal adrenocortical hyperplasia, suggesting a pathogenic role for glucocorticoids in this disorder. Considering this endocrine background, we examined whether the glucocorticoid receptor (GR) modulator CORT 113176 prevents spinal cord neuropathology of Wobblers. CORT 113176 shows high affinity for the GR, with low or null affinity for other steroid receptors. We employed five-month-old genotyped Wobbler mice that received s.c. vehicle or 30 mg/kg/day for 4 days of CORT 113176 dissolved in sesame oil. The mice were used on the 4th day, 2 h after the last dose of CORT 113176. Vehicle-treated Wobbler mice presented vacuolated motoneurons, increased glial fibrillary acidic protein (GFAP)+ astrocytes and decreased glutamine synthase (GS)+ cells. There was strong neuroinflammation, shown by increased staining for IBA1+ microglia and CD11b mRNA, enhanced expression of tumor necrosis factor-α, its cognate receptor TNFR1, toll-like receptor 4, the inducible nitric oxide synthase, NFkB and the high-mobility group box 1 protein (HMGB1). Treatment of Wobbler mice with CORT 113176 reversed the abnormalities of motoneurons and down-regulated proinflammatory mediators and glial reactivity. Expression of glutamate transporters GLT1 and GLAST mRNAs and GLT1 protein was significantly enhanced over untreated Wobblers. In summary, antagonism of GR with CORT 113176 prevented neuropathology and showed anti-inflammatory and anti-glutamatergic effects in the spinal cord of Wobbler mice. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Estrogen in cycling rats alters gene expression in the temporomandibular joint, trigeminal ganglia and trigeminal subnucleus caudalis/upper cervical cord junction

PubMed Central

Puri, Jyoti; Bellinger, Larry L.; Kramer, Phillip R.

2011-01-01

Females report temporomandibular joint (TMJ) pain more than men and studies suggest estrogen modulates this pain response. Our goal in this study was to determine genes that are modulated by physiological levels of 17β-estradiol that could have a role in TMJ pain. To complete this goal, saline or complete Freund’s adjuvant was injected in the TMJ when plasma 17β-estradiol was low or when it was at a high proestrus level. TMJ, trigeminal ganglion and trigeminal subnucleus caudalis/upper cervical cord junction (Vc/C1–2) tissues were isolated from the treated rats and expression of 184 genes was quantitated in each tissue using real time PCR. Significant changes in the amount of specific transcripts were observed in the TMJ tissues, trigeminal ganglia and Vc/C1–2 region when comparing rats with high and low estrogen. GABA A receptor subunit α6 (Gabra6) and the glycine receptor α2 (Glra2) were two genes of interest because of their direct function in neuronal activity and a greater than 29 fold increase in the trigeminal ganglia was observed in proestrus rats with TMJ inflammation. Immunohistochemical studies showed that Gabrα6 and Glrα2 neuronal and not glial expression increased when comparing rats with high and low estrogen. Estrogen receptors α and β are present in neurons of the trigeminal ganglia, whereby 17β-estradiol can alter expression of Gabrα6 and Glrα2. Also, estrogen receptor α (ERα) but not ERβ was observed in satellite glial cells of the trigeminal ganglia. These results demonstrate that genes associated with neurogenic inflammation or neuronal excitability were altered by changes in the concentration of 17β-estradiol. PMID:21321935

TNFa/TNFR2 signaling is required for glial ensheathment at the dorsal root entry zone

PubMed Central

Smith, Cody J.; Bagnat, Michel; Deppmann, Christopher D.

2017-01-01

Somatosensory information from the periphery is routed to the spinal cord through centrally-projecting sensory axons that cross into the central nervous system (CNS) via the dorsal root entry zone (DREZ). The glial cells that ensheath these axons ensure rapid propagation of this information. Despite the importance of this glial-axon arrangement, how this afferent nerve is assembled during development is unknown. Using in vivo, time-lapse imaging we show that as centrally-projecting pioneer axons from dorsal root ganglia (DRG) enter the spinal cord, they initiate expression of the cytokine TNFalpha. This induction coincides with ensheathment of these axons by associated glia via a TNF receptor 2 (TNFR2)-mediated process. This work identifies a signaling cascade that mediates peripheral glial-axon interactions and it functions to ensure that DRG afferent projections are ensheathed after pioneer axons complete their navigation, which promotes efficient somatosensory neural function. PMID:28379965

Human induced pluripotent stem cell-derived glial cells and neural progenitors display divergent responses to Zika and dengue infections.

PubMed

Muffat, Julien; Li, Yun; Omer, Attya; Durbin, Ann; Bosch, Irene; Bakiasi, Grisilda; Richards, Edward; Meyer, Aaron; Gehrke, Lee; Jaenisch, Rudolf

2018-06-18

Maternal Zika virus (ZIKV) infection during pregnancy is recognized as the cause of an epidemic of microcephaly and other neurological anomalies in human fetuses. It remains unclear how ZIKV accesses the highly vulnerable population of neural progenitors of the fetal central nervous system (CNS), and which cell types of the CNS may be viral reservoirs. In contrast, the related dengue virus (DENV) does not elicit teratogenicity. To model viral interaction with cells of the fetal CNS in vitro, we investigated the tropism of ZIKV and DENV for different induced pluripotent stem cell-derived human cells, with a particular focus on microglia-like cells. We show that ZIKV infected isogenic neural progenitors, astrocytes, and microglia-like cells (pMGLs), but was only cytotoxic to neural progenitors. Infected glial cells propagated ZIKV and maintained ZIKV load over time, leading to viral spread to susceptible cells. DENV triggered stronger immune responses and could be cleared by neural and glial cells more efficiently. pMGLs, when cocultured with neural spheroids, invaded the tissue and, when infected with ZIKV, initiated neural infection. Since microglia derive from primitive macrophages originating in proximity to the maternal vasculature, they may act as a viral reservoir for ZIKV and establish infection of the fetal brain. Infection of immature neural stem cells by invading microglia may occur in the early stages of pregnancy, before angiogenesis in the brain rudiments. Our data are also consistent with ZIKV and DENV affecting the integrity of the blood-brain barrier, thus allowing infection of the brain later in life.

Regenerative Potential of Ependymal Cells for Spinal Cord Injuries Over Time.

PubMed

Li, Xiaofei; Floriddia, Elisa M; Toskas, Konstantinos; Fernandes, Karl J L; Guérout, Nicolas; Barnabé-Heider, Fanie

2016-11-01

Stem cells have a high therapeutic potential for the treatment of spinal cord injury (SCI). We have shown previously that endogenous stem cell potential is confined to ependymal cells in the adult spinal cord which could be targeted for non-invasive SCI therapy. However, ependymal cells are an understudied cell population. Taking advantage of transgenic lines, we characterize the appearance and potential of ependymal cells during development. We show that spinal cord stem cell potential in vitro is contained within these cells by birth. Moreover, juvenile cultures generate more neurospheres and more oligodendrocytes than adult ones. Interestingly, juvenile ependymal cells in vivo contribute to glial scar formation after severe but not mild SCI, due to a more effective sealing of the lesion by other glial cells. This study highlights the importance of the age-dependent potential of stem cells and post-SCI environment in order to utilize ependymal cell's regenerative potential. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Inkjet printing Schwann cells and neuronal analogue NG108-15 cells.

PubMed

Tse, Christopher; Whiteley, Robert; Yu, Tong; Stringer, Jonathan; MacNeil, Sheila; Haycock, John W; Smith, Patrick J

2016-03-01

Porcine Schwann cells and neuronal analogue NG108-15 cells were printed using a piezoelectric-inkjet-printer with a nozzle diameter of 60 μm, within the range of 70-230 V, with analysis of viability and quality after printing. Neuronal and glial cell viabilities of >86% and >90% were detected immediately after printing and no correlation between voltage applied and cell viability could be seen. Printed neuronal cells were shown to produce neurites earlier compared to controls, and over several days, produced longer neurites which become most evident by day 7. The number of neurites becomes similar by day 7 also, and cells proliferate with a similar viability to that of non-printed cells (controls). This method of inkjet printing cells provides a technical platform for investigating neuron-glial cell interactions with no significant difference to cell viability than standard cell seeding. Such techniques can be utilized for lab-on-a-chip technologies and to create printed neural networks for neuroscience applications.

Enteric Glial Cells: A New Frontier in Neurogastroenterology and Clinical Target for Inflammatory Bowel Diseases.

PubMed

Ochoa-Cortes, Fernando; Turco, Fabio; Linan-Rico, Andromeda; Soghomonyan, Suren; Whitaker, Emmett; Wehner, Sven; Cuomo, Rosario; Christofi, Fievos L

2016-02-01

The word "glia" is derived from the Greek word "γλoια," glue of the enteric nervous system, and for many years, enteric glial cells (EGCs) were believed to provide mainly structural support. However, EGCs as astrocytes in the central nervous system may serve a much more vital and active role in the enteric nervous system, and in homeostatic regulation of gastrointestinal functions. The emphasis of this review will be on emerging concepts supported by basic, translational, and/or clinical studies, implicating EGCs in neuron-to-glial (neuroglial) communication, motility, interactions with other cells in the gut microenvironment, infection, and inflammatory bowel diseases. The concept of the "reactive glial phenotype" is explored as it relates to inflammatory bowel diseases, bacterial and viral infections, postoperative ileus, functional gastrointestinal disorders, and motility disorders. The main theme of this review is that EGCs are emerging as a new frontier in neurogastroenterology and a potential therapeutic target. New technological innovations in neuroimaging techniques are facilitating progress in the field, and an update is provided on exciting new translational studies. Gaps in our knowledge are discussed for further research. Restoring normal EGC function may prove to be an efficient strategy to dampen inflammation. Probiotics, palmitoylethanolamide (peroxisome proliferator-activated receptor-α), interleukin-1 antagonists (anakinra), and interventions acting on nitric oxide, receptor for advanced glycation end products, S100B, or purinergic signaling pathways are relevant clinical targets on EGCs with therapeutic potential.

Long term effects of lipopolysaccharide on satellite glial cells in mouse dorsal root ganglia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blum, E.; Procacci, P.; Conte, V.

Lipopolysaccharide (LPS) has been used extensively to study neuroinflammation, but usually its effects were examined acutely (24 h<). We have shown previously that a single intraperitoneal LPS injection activated satellite glial cells (SGCs) in mouse dorsal root ganglia (DRG) and altered several functional parameters in these cells for at least one week. Here we asked whether the LPS effects would persist for 1 month. We injected mice with a single LPS dose and tested pain behavior, assessed SGCs activation in DRG using glial fibrillary acidic protein (GFAP) immunostaining, and injected a fluorescent dye intracellularly to study intercellular coupling. Electron microscopymore » was used to quantitate changes in gap junctions. We found that at 30 days post-LPS the threshold to mechanical stimulation was lower than in controls. GFAP expression, as well as the magnitude of dye coupling among SGCs were greater than in controls. Electron microscopy analysis supported these results, showing a greater number of gap junctions and an abnormal growth of SGC processes. These changes were significant, but less prominent than at 7 days post-LPS. We conclude that a single LPS injection exerts long-term behavioral and cellular changes. The results are consistent with the idea that SGC activation contributes to hyperalgesia. - Highlights: • A single lipopolysaccharides injection activated glia in mouse dorsal root ganglia for 30 days. • This was accompanied by increased communications by gap junctions among glia and by hyperalgesia. • Glial activation and coupling may contribute to chronic pain.« less

Control of neuronal morphology and connectivity: emerging developmental roles for gap junctional proteins.

PubMed

Baker, Michael W; Macagno, Eduardo R

2014-04-17

Recent evidence indicates that gap junction (GJ) proteins can play a critical role in controlling neuronal connectivity as well as cell morphology in the developing nervous system. GJ proteins may function analogously to cell adhesion molecules, mediating cellular recognition and selective neurite adhesion. Moreover, during synaptogenesis electrical synapses often herald the later establishment of chemical synapses, and thus may help facilitate activity-dependent sculpting of synaptic terminals. Recent findings suggest that the morphology and connectivity of embryonic leech neurons are fundamentally organized by the type and perhaps location of the GJ proteins they express. For example, ectopic expression in embryonic leech neurons of certain innexins that define small GJ-linked networks of cells leads to the novel coupling of the expressing cell into that network. Moreover, gap junctions appear to mediate interactions among homologous neurons that modulate process outgrowth and stability. We propose that the selective formation of GJs between developing neurons and perhaps glial cells in the CNS helps orchestrate not only cellular synaptic connectivity but also can have a pronounced effect on the arborization and morphology of those cells involved. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

ONO-2506 inhibits spike-wave discharges in a genetic animal model without affecting traditional convulsive tests via gliotransmission regulation.

PubMed

Yamamura, Satoshi; Hoshikawa, Masamitsu; Dai, Kato; Saito, Hiromitsu; Suzuki, Noboru; Niwa, Osamu; Okada, Motohiro

2013-03-01

Anticonvulsants have been developed according to the traditional neurotransmission imbalance hypothesis. However, the anticonvulsive pharmacotherapy currently available remains unsatisfactory. To develop new antiepileptic drugs with novel antiepileptic mechanisms, we have tested the antiepileptic actions of ONO-2506, a glial modulating agent, and its effects on tripartite synaptic transmission. Dose-dependent effects of ONO-2506 on maximal-electroshock seizure (MES), pentylenetetrazol-induced seizure (PTZ) and epileptic discharge were determined in a genetic model of absence epilepsy in mice (Cacna1a(tm2Nobs/tm2Nobs) strain). Antiepileptic mechanisms of ONO-2506 were analysed by examining the interaction between ONO-2506 and transmission-modulating toxins (tetanus toxin, fluorocitrate, tetrodotoxin) on release of l-glutamate, d-serine, GABA and kynurenic acid in the medial-prefrontal cortex (mPFC) of freely moving rats using microdialysis and primary cultured rat astrocytes. ONO-2506 inhibited spontaneous epileptic discharges in Cacna1a(tm2Nobs/tm2Nobs) mice without affecting MES or PTZ. Given systemically, ONO-2506 increased basal release of GABA and kynurenic acid in the mPFC through activation of both neuronal and glial exocytosis, but inhibited depolarization-induced releases of all transmitters. ONO-2506 increased basal glial release of kynurenic acid without affecting those of l-glutamate, d-serine or GABA. However, ONO-2506 inhibited AMPA-induced releases of l-glutamate, d-serine, GABA and kynurenic acid. ONO-2506 did not affect traditional convulsive tests but markedly inhibited epileptic phenomena in the genetic epilepsy mouse model. ONO-2506 enhanced release of inhibitory neuro- and gliotransmitters during the resting stage and inhibited tripartite transmission during the hyperactive stage. The results suggest that ONO-2506 is a novel potential glial-targeting antiepileptic drug. This article is commented on by Onat, pp. 1086-1087 of this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.12050. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

Ca2+ Responses in Enteric Glia are Mediated by Connexin-43 Hemichannels and Modulate Colonic Transit in Mice

PubMed Central

Fried, David; Gomez-Suarez, Roberto A.; Leinninger, Gina M.; Sévigny, Jean; Parpura, Vladimir; Gulbransen, Brian D.

2014-01-01

Background & Aims In the enteric nervous system, neurotransmitters initiate changes in Ca2+ (Ca2+ responses) in glia, but it is not clear how this process affects intestinal function. We investigated whether Ca2+-mediated responses in enteric glial are required to maintain gastrointestinal function. Methods We used in situ Ca2+ imaging to monitor glial Ca2+ responses, which were manipulated with pharmacologic agents or via glia-specific disruption of the gene encoding connexin-43 (Cx43) (hGFAP::creERT2+/−/Cx43f/f mice). Gastrointestinal function was assessed based on pellet output, total gut transit, colonic bead expulsion, and muscle tension recordings. Proteins were localized and quantified by immunohistochemistry, immunoblot, and reverse transcription PCR analyses. Results Ca2+ responses in enteric glia of mice were mediated by Cx43 hemichannels. Cx43 immunoreactivity was confined to enteric glia within the myenteric plexus of the mouse colon; the Cx43 inhibitors carbenoxolone and 43Gap26 inhibited the ability of enteric glia to propagate Ca2+ responses. In vivo attenuation of Ca2+ responses in the enteric glial network slowed gut transit overall and delayed colonic transit—these changes are also observed during normal aging. Altered motility with increasing age was associated with reduced glial Ca2+-mediated responses and changes in glial expression of Cx43 mRNA and protein. Conclusions Ca2+-mediated responses in enteric glia regulate gastrointestinal function in mice. Altered intercellular signaling between enteric glia and neurons might contribute to motility disorders. PMID:24211490

Survival, migration, and differentiation of Sox1-GFP embryonic stem cells in coculture with an auditory brainstem slice preparation.

PubMed

Glavaski-Joksimovic, Aleksandra; Thonabulsombat, Charoensri; Wendt, Malin; Eriksson, Mikael; Palmgren, Björn; Jonsson, Anna; Olivius, Petri

2008-03-01

The poor regeneration capability of the mammalian hearing organ has initiated different approaches to enhance its functionality after injury. To evaluate a potential neuronal repair paradigm in the inner ear and cochlear nerve we have previously used embryonic neuronal tissue and stem cells for implantation in vivo and in vitro. At present, we have used in vitro techniques to study the survival and differentiation of Sox1-green fluorescent protein (GFP) mouse embryonic stem (ES) cells as a monoculture or as a coculture with rat auditory brainstem slices. For the coculture, 300 microm-thick brainstem slices encompassing the cochlear nucleus and cochlear nerve were prepared from postnatal SD rats. The slices were propagated using the membrane interface method and the cochlear nuclei were prelabeled with DiI. After some days in culture a suspension of Sox1 cells was deposited next to the brainstem slice. Following deposition Sox1 cells migrated toward the brainstem and onto the cochlear nucleus. GFP was not detectable in undifferentiated ES cells but became evident during neural differentiation. Up to 2 weeks after transplantation the cocultures were fixed. The undifferentiated cells were evaluated with antibodies against progenitor cells whereas the differentiated cells were determined with neuronal and glial markers. The morphological and immunohistochemical data indicated that Sox1 cells in monoculture differentiated into a higher percentage of glial cells than neurons. However, when a coculture was used a significantly lower percentage of Sox1 cells differentiated into glial cells. The results demonstrate that a coculture of Sox1 cells and auditory brainstem present a useful model to study stem cell differentiation.

Amitriptyline induces brain-derived neurotrophic factor (BDNF) mRNA expression through ERK-dependent modulation of multiple BDNF mRNA variants in primary cultured rat cortical astrocytes and microglia.

PubMed

Hisaoka-Nakashima, Kazue; Kajitani, Naoto; Kaneko, Masahiro; Shigetou, Takahiro; Kasai, Miho; Matsumoto, Chie; Yokoe, Toshiki; Azuma, Honami; Takebayashi, Minoru; Morioka, Norimitsu; Nakata, Yoshihiro

2016-03-01

A significant role of brain-derived neurotrophic factor (BDNF) has been previously implicated in the therapeutic effect of antidepressants. To ascertain the contribution of specific cell types in the brain that produce BDNF following antidepressant treatment, the effects of the tricyclic antidepressant amitriptyline on rat primary neuronal, astrocytic and microglial cortical cultures were examined. Amitriptyline increased the expression of BDNF mRNA in astrocytic and microglial cultures but not neuronal cultures. Antidepressants with distinct mechanisms of action, such as clomipramine, duloxetine and fluvoxamine, also increased BDNF mRNA expression in astrocytic and microglial cultures. There are multiple BDNF mRNA variants (exon I, IIA, IV and VI) expressed in astrocytes and microglia and the variant induced by antidepressants has yet to be elaborated. Treatment with antidepressants increased the expression of exon I, IV and VI in astrocyte and microglia. Clomipramine alone significantly upregulated expression of exon IIA. The amitriptyline-induced expression of both total and individual BDNF mRNA variants (exon I, IV and VI) were blocked by MEK inhibitor U0126, indicating MEK/ERK signaling is required in the expression of BDNF. These findings indicate that non-neural cells are a significant target of antidepressants and further support the contention that glial production of BDNF is crucial role in the therapeutic effect of antidepressants. The current data suggest that targeting of glial function could lead to the development of antidepressants with a truly novel mechanism of action. Copyright © 2016 Elsevier B.V. All rights reserved.

Opiate Drugs with Abuse Liability Hijack the Endogenous Opioid System to Disrupt Neuronal and Glial Maturation in the Central Nervous System.

PubMed

Hauser, Kurt F; Knapp, Pamela E

2017-01-01

The endogenous opioid system, comprised of multiple opioid neuropeptide and receptor gene families, is highly expressed by developing neural cells and can significantly influence neuronal and glial maturation. In many central nervous system (CNS) regions, the expression of opioid peptides and receptors occurs only transiently during development, effectively disappearing with subsequent maturation only to reemerge under pathologic conditions, such as with inflammation or injury. Opiate drugs with abuse liability act to modify growth and development by mimicking the actions of endogenous opioids. Although typically mediated by μ-opioid receptors, opiate drugs can also act through δ- and κ-opioid receptors to modulate growth in a cell-type, region-specific, and developmentally regulated manner. Opioids act as biological response modifiers and their actions are highly contextual, plastic, modifiable, and influenced by other physiological processes or pathophysiological conditions, such as neuro-acquired immunodeficiency syndrome. To date, most studies have considered the acute effects of opiates on cellular maturation. For example, activating opioid receptors typically results in acute growth inhibition in both neurons and glia. However, with sustained opioid exposure, compensatory factors become operative, a concept that has been largely overlooked during CNS maturation. Accordingly, this article surveys prior studies on the effects of opiates on CNS maturation, and also suggests new directions for future research in this area. Identifying the cellular and molecular mechanisms underlying the adaptive responses to chronic opiate exposure (e.g., tolerance) during maturation is crucial toward understanding the consequences of perinatal opiate exposure on the CNS.

Identification of translational activators of glial glutamate transporter EAAT2 through cell-based high-throughput screening: an approach to prevent excitotoxicity.

PubMed

Colton, Craig K; Kong, Qiongman; Lai, Liching; Zhu, Michael X; Seyb, Kathleen I; Cuny, Gregory D; Xian, Jun; Glicksman, Marcie A; Lin, Chien-Liang Glenn

2010-07-01

Excitotoxicity has been implicated as the mechanism of neuronal damage resulting from acute insults such as stroke, epilepsy, and trauma, as well as during the progression of adult-onset neurodegenerative disorders such as Alzheimer's disease and amyotrophic lateral sclerosis (ALS). Excitotoxicity is defined as excessive exposure to the neurotransmitter glutamate or overstimulation of its membrane receptors, leading to neuronal injury or death. One potential approach to protect against excitotoxic neuronal damage is enhanced glutamate reuptake. The glial glutamate transporter EAAT2 is the quantitatively dominant glutamate transporter and plays a major role in clearance of glutamate. Expression of EAAT2 protein is highly regulated at the translational level. In an effort to identify compounds that can induce translation of EAAT2 transcripts, a cell-based enzyme-linked immunosorbent assay was developed using a primary astrocyte line stably transfected with a vector designed to identify modulators of EAAT2 translation. This assay was optimized for high-throughput screening, and a library of approximately 140,000 compounds was tested. In the initial screen, 293 compounds were identified as hits. These 293 hits were retested at 3 concentrations, and a total of 61 compounds showed a dose-dependent increase in EAAT2 protein levels. Selected compounds were tested in full 12-point dose-response experiments in the screening assay to assess potency as well as confirmed by Western blot, immunohistochemistry, and glutamate uptake assays to evaluate the localization and function of the elevated EAAT2 protein. These hits provide excellent starting points for developing therapeutic agents to prevent excitotoxicity.

Increased apoptosis and reduced neuronal and glial densities in the hippocampus due to nicotine and ethanol exposure in adolescent mice.

PubMed

Oliveira-da-Silva, Andreia; Vieira, Fernanda B; Cristina-Rodrigues, Fabiana; Filgueiras, Cláudio C; Manhães, Alex C; Abreu-Villaça, Yael

2009-10-01

It has been recently shown that nicotine and ethanol interact during adolescence affecting memory/learning and anxiety levels. Considering the role of the hippocampus in both anxiety and memory/learning, we investigated whether adolescent nicotine and/or ethanol administration elicit apoptotic cell death and whether this results in neuronal and/or glial density alterations in the following regions of the hippocampus: granular layer of the dentate gyrus (GrDG), molecular layer (Mol), CA1, CA2 and CA3. From the 30th to the 45th postnatal day, C57BL/6 male and female mice were exposed to nicotine free base (NIC) and/or ethanol (ETOH). Four groups were analyzed: (1) concomitant NIC (50mug/ml in 2% saccharin to drink) and ETOH (25%, 2g/kg i.p. injected every other day) exposure; (2) NIC exposure; (3) ETOH exposure; (4) vehicle. We evaluated cell degeneration (TUNEL assay), neuronal and glial densities (optical disector) and region thicknesses at the end of the period of exposure. Our results demonstrate that ETOH elicited an increase in TUNEL-positive cells relative to the vehicle group in all hippocampal regions. NIC elicited less severe region-dependent effects: the number of TUNEL-positive cells was significantly increased in the Mol and CA1 when compared to the vehicle group. These results were paralleled by reductions in neuronal and glial cells densities, which indicate that both cell types are sensitive to the neurotoxic effects of these drugs. There were no effects on region thicknesses. On the other hand, concomitant NIC and ETOH reduced the adverse effects of the drugs when administered separately. This ability of nicotine and ethanol co-exposure to lessen the adverse effects of nicotine and ethanol may contribute to adolescents co-use and co-abuse of tobacco and alcoholic beverages.

Synthesis and deposition of basement membrane proteins by primary brain capillary endothelial cells in a murine model of the blood-brain barrier.

PubMed

Thomsen, Maj Schneider; Birkelund, Svend; Burkhart, Annette; Stensballe, Allan; Moos, Torben

2017-03-01

The brain vascular basement membrane is important for both blood-brain barrier (BBB) development, stability, and barrier integrity and the contribution hereto from brain capillary endothelial cells (BCECs), pericytes, and astrocytes of the BBB is probably significant. The aim of this study was to analyse four different in vitro models of the murine BBB for expression and possible secretion of major basement membrane proteins from murine BCECs (mBCECs). mBCECs, pericytes and glial cells (mainly astrocytes and microglia) were prepared from brains of C57BL/6 mice. The mBCECs were grown as monoculture, in co-culture with pericytes or mixed glial cells, or as a triple-culture with both pericytes and mixed glial cells. The integrity of the BBB models was validated by measures of transendothelial electrical resistance (TEER) and passive permeability to mannitol. The expression of basement membrane proteins was analysed using RT-qPCR, mass spectrometry and immunocytochemistry. Co-culturing mBCECs with pericytes, mixed glial cells, or both significantly increased the TEER compared to the monoculture, and a low passive permeability was correlated with high TEER. The mBCECs expressed all major basement membrane proteins such as laminin-411, laminin-511, collagen [α1(IV)] 2 α2(IV), agrin, perlecan, and nidogen 1 and 2 in vitro. Increased expression of the laminin α5 subunit correlated with the addition of BBB-inducing factors (hydrocortisone, Ro 20-1724, and pCPT-cAMP), whereas increased expression of collagen IV α1 primarily correlated with increased levels of cAMP. In conclusion, BCECs cultured in vitro coherently form a BBB and express basement membrane proteins as a feature of maturation. Cover Image for this issue: doi: 10.1111/jnc.13789. © 2016 International Society for Neurochemistry.

Innate (inherent) control of brain infection, brain inflammation and brain repair: the role of microglia, astrocytes, "protective" glial stem cells and stromal ependymal cells.

PubMed

Hauwel, Mathieu; Furon, Emeline; Canova, Cecile; Griffiths, Mark; Neal, Jim; Gasque, Philippe

2005-04-01

In invertebrates and primitive vertebrates, the brain contains large numbers of "professional" macrophages associated with neurones, ependymal tanycytes and radial glia to promote robust regenerative capacity. In higher vertebrates, hematogenous cells are largely excluded from the brain, and innate immune molecules and receptors produced by the resident "amateur" macrophages (microglia, astrocytes and ependymal cells) control pathogen infiltration and clearance of toxic cell debris. However, there is minimal capacity for regeneration. The transfer of function from hematogenous cells to macroglia and microglia is associated with the sophistication of a yet poorly-characterized neurone-glia network. This evolutionary pattern may have been necessary to reduce the risk of autoimmune attack while preserving the neuronal web but the ability to repair central nervous system damage may have been sacrificed in the process. We herein argue that it may be possible to re-educate and stimulate the resident phagocytes to promote clearance of pathogens (e.g., Prion), toxic cell debris (e.g., amyloid fibrils and myelin) and apoptotic cells. Moreover, as part of this greater division of labour between cell types in vertebrate brains, it may be possible to harness the newly described properties of glial stem cells in neuronal protection (revitalization) rather than replacement, and to control brain inflammation. We will also highlight the emerging roles of stromal ependymal cells in controlling stem cell production and migration into areas of brain damage. Understanding the mechanisms involved in the nurturing of damaged neurons by protective glial stem cells with the safe clearance of cell debris could lead to remedial strategies for chronic brain diseases.

Glial Biomarkers in Human Central Nervous System Disease

PubMed Central

Garden, Gwenn A.; Campbell, Brian M.

2017-01-01

There is a growing understanding that aberrant GLIA function is an underlying factor in psychiatric and neurological disorders. As drug discovery efforts begin to focus on glia-related targets, a key gap in knowledge includes the availability of validated biomarkers to help determine which patients suffer from dysfunction of glial cells or who may best respond by targeting glia-related drug mechanisms. Biomarkers are biological variables with a significant relationship to parameters of disease states and can be used as surrogate markers of disease pathology, progression, and/or responses to drug treatment. For example, imaging studies of the CNS enable localization and characterization of anatomical lesions without the need to isolate tissue for biopsy. Many biomarkers of disease pathology in the CNS involve assays of glial cell function and/or response to injury. Each major glia subtype (oligodendroglia, astroglia and microglia) are connected to a number of important and useful biomarkers. Here, we describe current and emerging glial based biomarker approaches for acute CNS injury and the major categories of chronic nervous system dysfunction including neurodegenerative, neuropsychiatric, neoplastic, and autoimmune disorders of the CNS. These descriptions are highlighted in the context of how biomarkers are employed to better understand the role of glia in human CNS disease and in the development of novel therapeutic treatments. PMID:27228454

Sensory Response of Transplanted Astrocytes in Adult Mammalian Cortex In Vivo

PubMed Central

Zhang, Kuan; Chen, Chunhai; Yang, Zhiqi; He, Wenjing; Liao, Xiang; Ma, Qinlong; Deng, Ping; Lu, Jian; Li, Jingcheng; Wang, Meng; Li, Mingli; Zheng, Lianghong; Zhou, Zhuan; Sun, Wei; Wang, Liting; Jia, Hongbo; Yu, Zhengping; Zhou, Zhou; Chen, Xiaowei

2016-01-01

Glial precursor transplantation provides a potential therapy for brain disorders. Before its clinical application, experimental evidence needs to indicate that engrafted glial cells are functionally incorporated into the existing circuits and become essential partners of neurons for executing fundamental brain functions. While previous experiments supporting for their functional integration have been obtained under in vitro conditions using slice preparations, in vivo evidence for such integration is still lacking. Here, we utilized in vivo two-photon Ca2+ imaging along with immunohistochemistry, fluorescent indicator labeling-based axon tracing and correlated light/electron microscopy to analyze the profiles and the functional status of glial precursor cell-derived astrocytes in adult mouse neocortex. We show that after being transplanted into somatosensory cortex, precursor-derived astrocytes are able to survive for more than a year and respond with Ca2+ signals to sensory stimulation. These sensory-evoked responses are mediated by functionally-expressed nicotinic receptors and newly-established synaptic contacts with the host cholinergic afferents. Our results provide in vivo evidence for a functional integration of transplanted astrocytes into adult mammalian neocortex, representing a proof-of-principle for sensory cortex remodeling through addition of essential neural elements. Moreover, we provide strong support for the use of glial precursor transplantation to understand glia-related neural development in vivo. PMID:27405333

Neuronal and mixed neuronal glial tumors associated to epilepsy. A heterogeneous and related group of tumours.

PubMed

Moreno, A; de Felipe, J; García Sola, R; Navarro, A; Ramón y Cajal, S

2001-04-01

The group of brain tumors with mature components encompasses several pathological entities including: the ganglioneuroma; the gangliocytoma; the ganglioglioma; the desmoplastic ganglioglioma; the neurocitoma and a group of glioneuronal hamartomatous tumorous lesions, such as meningoangiomatosis. The dysembryoplastic neuroepithelial tumor is characterized by the presence of multiple cortical nodules made up of small, oligo-like cells and a myxoid pattern rich in mucopolysaccharides. Mature neuronal cells are frequently detected throughout the tumor. Most of them are associated with microhamartias in the adjacent brain and pharmacoresistant epilepsy. The excellent prognosis of the majority of these tumors and the potential for malignant transformation of the glial component in the ganglioglioma are the two most remarkable findings. Histological signs of anaplasia and greater mitotic and proliferative activities are associated with local recurrences. Atypical neurocytomas occur only exceptionally. Treatment choices are surgical resectioning and, in those cases presenting greater proliferative activity and cytological atypia, postoperative radiotherapy may be recommended. This paper reviews this heterogeneous group of neoplasms and hamartomatous lesions, pointing out presumable transitions among the different types of mixed neuronal and glial brain tumors. A single term of "mixed neuronal-glial tumors" is defended, distinguishing different subgroups of tumors, depending on the predominant cellular component.

Glial Draper Rescues Aβ Toxicity in a Drosophila Model of Alzheimer's Disease.

PubMed

Ray, Arpita; Speese, Sean D; Logan, Mary A

2017-12-06

Pathological hallmarks of Alzheimer's disease (AD) include amyloid-β (Aβ) plaques, neurofibrillary tangles, and reactive gliosis. Glial cells offer protection against AD by engulfing extracellular Aβ peptides, but the repertoire of molecules required for glial recognition and destruction of Aβ are still unclear. Here, we show that the highly conserved glial engulfment receptor Draper/MEGF10 provides neuroprotection in an AD model of Drosophila (both sexes). Neuronal expression of human Aβ42 arc in adult flies results in robust Aβ accumulation, neurodegeneration, locomotor dysfunction, and reduced lifespan. Notably, all of these phenotypes are more severe in draper mutant animals, whereas enhanced expression of glial Draper reverses Aβ accumulation, as well as behavioral phenotypes. We also show that the signal transducer and activator of transcription (Stat92E), c-Jun N-terminal kinase (JNK)/AP-1 signaling, and expression of matrix metalloproteinase-1 (Mmp1) are activated downstream of Draper in glia in response to Aβ42 arc exposure. Furthermore, Aβ42-induced upregulation of the phagolysosomal markers Atg8 and p62 was notably reduced in draper mutant flies. Based on our findings, we propose that glia clear neurotoxic Aβ peptides in the AD model Drosophila brain through a Draper/STAT92E/JNK cascade that may be coupled to protein degradation pathways such as autophagy or more traditional phagolysosomal destruction methods. SIGNIFICANCE STATEMENT Alzheimer's disease (AD) and similar dementias are common incurable neurodegenerative disorders in the aging population. As the primary immune responders in the brain, glial cells are implicated as key players in the onset and progression of AD and related disorders. Here we show that the glial engulfment receptor Draper is protective in a Drosophila model of AD, reducing levels of amyloid β (Aβ) peptides, reversing locomotor defects, and extending lifespan. We further show that protein degradation pathways are induced downstream of Draper in AD model flies, supporting a model in which glia engulf and destroy Aβ peptides to reduce amyloid-associated toxicity. Copyright © 2017 the authors 0270-6474/17/3711881-13$15.00/0.

Low-Dose Curcumin Stimulates Proliferation, Migration and Phagocytic Activity of Olfactory Ensheathing Cells

PubMed Central

Tello Velasquez, Johana; Watts, Michelle E.; Todorovic, Michael; Nazareth, Lynnmaria; Pastrana, Erika; Diaz-Nido, Javier; Lim, Filip; Ekberg, Jenny A. K.; Quinn, Ronald J.; John, James A. St

2014-01-01

One of the promising strategies for neural repair therapies is the transplantation of olfactory ensheathing cells (OECs) which are the glial cells of the olfactory system. We evaluated the effects of curcumin on the behaviour of mouse OECs to determine if it could be of use to further enhance the therapeutic potential of OECs. Curcumin, a natural polyphenol compound found in the spice turmeric, is known for its anti-cancer properties at doses over 10 µM, and often at 50 µM, and it exerts its effects on cancer cells in part by activation of MAP kinases. In contrast, we found that low-dose curcumin (0.5 µM) applied to OECs strikingly modulated the dynamic morphology, increased the rate of migration by up to 4-fold, and promoted significant proliferation of the OECs. Most dramatically, low-dose curcumin stimulated a 10-fold increase in the phagocytic activity of OECs. All of these potently stimulated behavioural characteristics of OECs are favourable for neural repair therapies. Importantly, low-dose curcumin gave a transient activation of p38 kinases, which is in contrast to the high dose curcumin effects on cancer cells in which these MAP kinases tend to undergo prolonged activation. Low-dose curcumin mediated effects on OECs demonstrate cell-type specific stimulation of p38 and ERK kinases. These results constitute the first evidence that low-dose curcumin can modulate the behaviour of olfactory glia into a phenotype potentially more favourable for neural repair and thereby improve the therapeutic use of OECs for neural repair therapies. PMID:25360677

Enterocolitis induced by autoimmune targeting of enteric glial cells: A possible mechanism in Crohn's disease?

NASA Astrophysics Data System (ADS)

Cornet, Anne; Savidge, Tor C.; Cabarrocas, Julie; Deng, Wen-Lin; Colombel, Jean-Frederic; Lassmann, Hans; Desreumaux, Pierre; Liblau, Roland S.

2001-11-01

Early pathological manifestations of Crohn's disease (CD) include vascular disruption, T cell infiltration of nerve plexi, neuronal degeneration, and induction of T helper 1 cytokine responses. This study demonstrates that disruption of the enteric glial cell network in CD patients represents another early pathological feature that may be modeled after CD8+ T cell-mediated autoimmune targeting of enteric glia in double transgenic mice. Mice expressing a viral neoself antigen in astrocytes and enteric glia were crossed with specific T cell receptor transgenic mice, resulting in apoptotic depletion of enteric glia to levels comparable in CD patients. Intestinal and mesenteric T cell infiltration, vasculitis, T helper 1 cytokine production, and fulminant bowel inflammation were characteristic hallmarks of disease progression. Immune-mediated damage to enteric glia therefore may participate in the initiation and/or the progression of human inflammatory bowel disease.

Potassium accumulation by the glial membrane pump as revealed by membrane potential recording from isolated rabbit retinal Müller cells.

PubMed

Reichenbach, A; Nilius, B; Eberhardt, W

1986-01-30

Müller (glial) cells were isolated from rabbit retinae by papaine and mechanical dissociation. In a special perfusion chamber, the cells were penetrated with a recording electrode. When high-K+ solutions were applied into the environment of the cells by means of a second micropipette, the cell membrane depolarized strongly. During prolonged application of high-K+ solutions, however, there occurred a marked repolarization, and after cessation of high-K+ application, a strong hyperpolarization was observed. Both effects disappeared under the influence of ouabain, suggesting the accumulation of intracellular K+ by an active membrane pump. The data were used for calculation of the membrane's Na+:K+ permeability ratio, the intracellular K+ concentration, the pump rate and the mean pump site density. The calculated values are in good agreement with published data from mammalian astrocytes and are compared with those from amphibian Müller cells.

Ultra-low dose naltrexone attenuates chronic morphine-induced gliosis in rats.

PubMed

Mattioli, Theresa-Alexandra M; Milne, Brian; Cahill, Catherine M

2010-04-16

The development of analgesic tolerance following chronic morphine administration can be a significant clinical problem. Preclinical studies demonstrate that chronic morphine administration induces spinal gliosis and that inhibition of gliosis prevents the development of analgesic tolerance to opioids. Many studies have also demonstrated that ultra-low doses of naltrexone inhibit the development of spinal morphine antinociceptive tolerance and clinical studies demonstrate that it has opioid sparing effects. In this study we demonstrate that ultra-low dose naltrexone attenuates glial activation, which may contribute to its effects on attenuating tolerance. Spinal cord sections from rats administered chronic morphine showed significantly increased immuno-labelling of astrocytes and microglia compared to saline controls, consistent with activation. 3-D images of astrocytes from animals administered chronic morphine had significantly larger volumes compared to saline controls. Co-injection of ultra-low dose naltrexone attenuated this increase in volume, but the mean volume differed from saline-treated and naltrexone-treated controls. Astrocyte and microglial immuno-labelling was attenuated in rats co-administered ultra-low dose naltrexone compared to morphine-treated rats and did not differ from controls. Glial activation, as characterized by immunohistochemical labelling and cell size, was positively correlated with the extent of tolerance developed. Morphine-induced glial activation was not due to cell proliferation as there was no difference observed in the total number of glial cells following chronic morphine treatment compared to controls. Furthermore, using 5-bromo-2-deoxyuridine, no increase in spinal cord cell proliferation was observed following chronic morphine administration. Taken together, we demonstrate a positive correlation between the prevention of analgesic tolerance and the inhibition of spinal gliosis by treatment with ultra-low dose naltrexone. This research provides further validation for using ultra-low dose opioid receptor antagonists in the treatment of various pain syndromes.

Characterization of cortical neuronal and glial alterations during culture of organotypic whole brain slices from neonatal and mature mice.

PubMed

Staal, Jerome A; Alexander, Samuel R; Liu, Yao; Dickson, Tracey D; Vickers, James C

2011-01-01

Organotypic brain slice culturing techniques are extensively used in a wide range of experimental procedures and are particularly useful in providing mechanistic insights into neurological disorders or injury. The cellular and morphological alterations associated with hippocampal brain slice cultures has been well established, however, the neuronal response of mouse cortical neurons to culture is not well documented. In the current study, we compared the cell viability, as well as phenotypic and protein expression changes in cortical neurons, in whole brain slice cultures from mouse neonates (P4-6), adolescent animals (P25-28) and mature adults (P50+). Cultures were prepared using the membrane interface method. Propidium iodide labeling of nuclei (due to compromised cell membrane) and AlamarBlue™ (cell respiration) analysis demonstrated that neonatal tissue was significantly less vulnerable to long-term culture in comparison to the more mature brain tissues. Cultures from P6 animals showed a significant increase in the expression of synaptic markers and a decrease in growth-associated proteins over the entire culture period. However, morphological analysis of organotypic brain slices cultured from neonatal tissue demonstrated that there were substantial changes to neuronal and glial organization within the neocortex, with a distinct loss of cytoarchitectural stratification and increased GFAP expression (p<0.05). Additionally, cultures from neonatal tissue had no glial limitans and, after 14 DIV, displayed substantial cellular protrusions from slice edges, including cells that expressed both glial and neuronal markers. In summary, we present a substantial evaluation of the viability and morphological changes that occur in the neocortex of whole brain tissue cultures, from different ages, over an extended period of culture.

The role of P2X7R/ERK signaling in dorsal root ganglia satellite glial cells in the development of chronic postsurgical pain induced by skin/muscle incision and retraction (SMIR).

PubMed

Song, Jingnian; Ying, Yanlu; Wang, Wei; Liu, Xianguo; Xu, Xuebing; Wei, Xuhong; Ruan, Xiangcai

2018-03-01

The mechanisms of chronic postsurgical pain remain to be elucidated. We reported here that skin/muscle incision and retraction (SMIR), a rat model of postsurgical pain, phosphorylated the extracellular regulated protein kinases (ERK) signaling components c-Raf, MEK (ERK kinase) and ERK1/2 in lumbar 3 dorsal root ganglion (L3 DRG) in rats. Intrathecal injection of ERK specific inhibitor SCH772984 suppressed the mechanical allodynia induced by SMIR. Furthermore, SMIR upregulated tumor necrosis factor alpha (TNFα) in L3 DRG, which could be inhibited by SCH772984. Intrathecal injection of TNF antagonist Etanercept could also inhibit the mechanical allodynia and the increased ERK phosphorylation in L3 DRG induced by SMIR. In addition, immunofluorescent data showed that P2X7R was located exclusively in GFAP labeled satellite glial cells and was highly colocalized with p-ERK1/2 following SMIR. Pretreatment with P2X7R antagonist Brilliant Blue G (BBG) could also block the mechanical allodynia, inhibited the phosphorylation of c-Raf, MEK, ERK1/2, and decrease the expression of TNF-α. Finally, intrathecal injection of BzATP produced mechanical allodynia and induced ERK phosphorylation in satellite glial cells in L3 DRG. Thus, P2X7R activation in satellite glial cells in L3 DRG, leading to a positive feedback between ERK pathway activation and TNF-α production, is suggested to be involved in the induction of chronic postsurgical pain following SMIR. Copyright © 2017 Elsevier Inc. All rights reserved.

The present and future of opioid analgesics in small animal practice.

PubMed

Simon, B T; Steagall, P V

2017-08-01

Opioids are the cornerstone for the treatment of acute pain in small animal patients. This is primarily because of their remarkable safety profile, high efficacy, and benefit of reversibility. There have been some significant advances in our knowledge on opioid pharmacology and clinical usage in companion animal medicine. This review discusses the progression of opioid use in small animal practice providing current misconceptions and controversies in light of routes of administration. Potential targets for research and drug development and novel therapies are discussed in addition to the concepts of glial cell modulators, individual variability, and opioid tolerance and hyperalgesia. The future brings an interesting perspective with the application of pharmacogenetics and individualized pain management in canine and feline practice. © 2016 John Wiley & Sons Ltd.

Gliogenesis: historical perspectives, 1839-1985.

PubMed

Webster, Henry deF; Aström, Karl E

2009-01-01

This historical review of gliogenesis begins with Schwann's introduction of the cell doctrine in 1839. Subsequent microscopic studies revealed the cellular structure of many organs and tissues, but the CNS was thought to be different. In 1864, Virchow created the concept that nerve cells are held together by a "Nervenkitte" which he called"glia" (for glue). He and his contemporaries thought that "glia" was an unstructured, connective tissue-like ground substance that separated nerve cells from each other and from blood vessels. Dieters, a pupil of Virchow, discovered that this ground substance contained cells, which he described and illustrated. Improvements in microscopes and discovery of metallic impregnation methods finally showed convincingly that the "glia" was not a binding substance. Instead, it was composed of cells, each separate and distinct from neighboring cells and each with its own characteristic array of processes. Light microscopic studies of developing and mature nervous tissue led to the discovery of different types of glial cells-astroglia, oligodendroglia, microglia, and ependymal cells in the CNS, and Schwann cells in the peripheral nervous system (PNS). Subsequent studies characterized the origins and development of each type of glial cell. A new era began with the introduction of electron microscopy, immunostaining, and in vitro maintenance of both central and peripheral nervous tissue. Other methods and models greatly expanded our understanding of how glia multiply, migrate, and differentiate. In 1985, almost a century and a half of study had produced substantial progress in our understanding of glial cells, including their origins and development. Major advances were associated with the discovery of new methods. These are summarized first. Then the origins and development of astroglia, oligodendroglia, microglia, ependymal cells, and Schwann cells are described and discussed. In general, morphology is emphasized. Findings related to cytodifferentiation, cellular interactions, functions, and regulation of developing glia have also been included.

Postnatal neurogenesis in the cow pineal gland: an immunohistochemical study.

PubMed

Gómez Esteban, M B; Muñoz Mosqueira, M I; Arroyo, A A; Muñoz Barragán, L

2013-03-01

In the pineal gland of cows and rats structures designated rosettes have been described both during embryonic development and in adult animals. In order to investigate the possible nature of the cells comprising such structures, in the present work we studied the pineal glands from 10 cows of one- or four-years-old using conventional immunocytochemical and confocal microscopy techniques. As markers of glial cells, we used anti-vimentin (Vim) and glial fibrillary acidic protein (GFAP) and anti-S-100 sera, and the pinealocytes were labelled with β-III tubulin. As a marker of stem cells, we used an antinestin serum, while an anti-PCNA serum was employed to label proliferating cells. To explore the neuronal nature of some cells of the rosettes, we used an anti-SRIF serum. The rosettes were seen to be present throughout the glandular parenchyma and displayed a central cavity surrounded by cells, most of which expressed all or just some of the above glial labels and nestin, although there were also some rosettes with cells that expressed β-III tubulin and other cells that expressed SRIF. Likewise, in the cells of the rosettes the cell nucleus showed strong expression of PCNA. Confocal microscopy revealed that the walls of the rosettes contained cells that coexpressed Vim/S-100, Vim/GFAP and Vim/nestin. The number of rosettes was significantly greater in the animals of one year of age with respect to the four-year-old cows. The present findings allow us to suggest that rosettes are evolving structures and that most of the cells present in their walls should be considered stem cells, and hence responsible for the postnatal neurogenesis occurring in the pineal gland of cows.

Emerging Targets in Pituitary Adenomas: Role of the CXCL12/CXCR4-R7 System.

PubMed

Barbieri, Federica; Thellung, Stefano; Würth, Roberto; Gatto, Federico; Corsaro, Alessandro; Villa, Valentina; Nizzari, Mario; Albertelli, Manuela; Ferone, Diego; Florio, Tullio

2014-01-01

Chemokines are chemotactic regulators of immune surveillance in physiological and pathological conditions such as inflammation, infection, and cancer. Several chemokines and cognate receptors are constitutively expressed in the central nervous system, not only in glial and endothelial cells but also in neurons, controlling neurogenesis, neurite outgrowth, and axonal guidance during development. In particular, the chemokine CXCL12 and its receptors, CXCR4 and CXCR7, form a functional network that controls plasticity in different brain areas, influencing neurotransmission, neuromodulation, and cell migration, and the dysregulation of this chemokinergic axis is involved in several neurodegenerative, neuroinflammatory, and malignant diseases. CXCR4 primarily mediates the transduction of proliferative signals, while CXCR7 seems to be mainly responsible for scavenging CXCL12. Importantly, the multiple intracellular signalling generated by CXCL12 interaction with its receptors influences hypothalamic modulation of neuroendocrine functions, although a direct modulation of pituitary functioning via autocrine/paracrine mechanisms was also reported. Both CXCL12 and CXCR4 are constitutively overexpressed in pituitary adenomas and their signalling induces cell survival and proliferation, as well as hormonal hypersecretion. In this review we focus on the physiological and pathological functions of immune-related cyto- and chemokines, mainly focusing on the CXCL12/CXCR4-7 axis, and their role in pituitary tumorigenesis. Accordingly, we discuss the potential targeting of CXCR4 as novel pharmacological approach for pituitary adenomas.

Trehalose rescues glial cell dysfunction in striatal cultures from HD R6/1 mice at early postnatal development.

PubMed

Perucho, Juan; Gómez, Ana; Muñoz, María Paz; de Yébenes, Justo García; Mena, María Ángeles; Casarejos, María José

2016-07-01

The pathological hallmark of Huntington disease (HD) is the intracellular aggregation of mutant huntingtin (mHTT) in striatal neurons and glia associated with the selective loss of striatal medium-sized spiny neurons. Up to the present, the role of glia in HD is poorly understood and has been classically considered secondary to neuronal disorder. Trehalose is a disaccharide known to possess many pharmacological properties, acting as an antioxidant, a chemical chaperone, and an inducer of autophagy. In this study, we analyzed at an early postnatal development stage the abnormalities observed in striatal glial cell cultures of postnatal R6/1 mice (HD glia), under baseline and stressing conditions and the protective effects of trehalose. Our data demonstrate that glial HD alterations already occur at early stages of postnatal development. After 20 postnatal days in vitro, striatal HD glia cultures showed more reactive astrocytes with increased expression of glial fibrillary acidic protein (GFAP) but with less replication capacity, less A2B5(+) glial progenitors and more microglia than wild-type (WT) cultures. HD glia had lower levels of intracellular glutathione (GSH) and was more susceptible to H2O2 and epoxomicin insults. The amount of expressed GDNF and secreted mature-BDNF by HD astrocytes were much lower than by WT astrocytes. In addition, HD glial cultures showed a deregulation of the major proteolytic systems, the ubiquitin-proteasomal system (UPS), and the autophagic pathway. This produces a defective protein quality control, indicated by the elevated levels of ubiquitination and p62 protein. Interestingly, we show that trehalose, through its capacity to induce autophagy, inhibited p62/SQSTM1 accumulation and facilitated the degradation of cytoplasmic aggregates from mHTT and α-synuclein proteins. Trehalose also reduced microglia activation and reversed the disrupted cytoskeleton of astrocytes accompanied with an increase in the replication capacity. In addition, trehalose up-regulated mature-BDNF neurotrophic factor expression and secretion, probably mediating cytoskeletal organization and helping in vesicular BDNF transport. Together, these findings indicate that glia suffers functional early changes in the disease process, changes that may contribute to HD neurodegeneration. Trehalose could be a very promising compound for treatment of HD and other diseases with abnormal protein aggregates. Furthermore our study identifies glial cells as a novel target for trehalose to induce neurotrophic and neuroprotective actions in HD. Copyright © 2016 Elsevier Inc. All rights reserved.

The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology

PubMed Central

Murk, Kai; Blanco Suarez, Elena M.; Cockbill, Louisa M. R.; Banks, Paul; Hanley, Jonathan G.

2013-01-01

Summary Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult. PMID:23843614

Acute in utero exposure to lipopolysaccharide induces inflammation in the pre- and postnatal brain and alters the glial cytoarchitecture in the developing amygdala.

PubMed

O'Loughlin, Elaine; Pakan, Janelle M P; Yilmazer-Hanke, Deniz; McDermott, Kieran W

2017-11-02

Maternal immune activation (MIA) is a risk factor for neurodevelopmental disorders such as autism and schizophrenia, as well as seizure development. The amygdala is a brain region involved in the regulation of emotions, and amygdalar maldevelopment due to infection-induced MIA may lead to amygdala-related disorders. MIA priming of glial cells during development has been linked to abnormalities seen in later life; however, little is known about its effects on amygdalar biochemical and cytoarchitecture integrity. Time-mated C57BL6J mice were administered a single intraperitoneal injection of 50 μg/kg lipopolysaccharide (LPS) on embryonic day 12 (E12), and the effects of MIA were examined at prenatal, neonatal, and postnatal developmental stages using immunohistochemistry, real-time quantitative PCR, and stereological quantification of cytoarchitecture changes. Fetal brain expression of pro-inflammatory cytokines (IL-1β, TNFα, and IL-6) was significantly upregulated at 4 h postinjection (E12) and remained elevated until the day of birth (P0). In offspring from LPS-treated dams, amygdalar expression of pro-inflammatory cytokines was also increased on day 7 (P7) and expression was sustained on day 40 (P40). Toll-like receptor (TLR-2, TLR-4) expression was also upregulated in fetal brains and in the postnatal amygdala in LPS-injected animals. Morphological examination of cells expressing ionized calcium-binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) suggested long-term microglial activation and astrogliosis in postnatal amygdalar regions. Our results showed that LPS-induced MIA at E12 induces a pro-inflammatory cytokine profile in the developing fetal brain that continues up to early adulthood in the amygdala. Inflammation elicited by MIA may activate cells in the fetal brain and lead to alterations in glial (microglia and astrocyte) cells observed in the postnatal amygdala. Moreover, increased pro-inflammatory cytokines and their effects on glial subpopulations may in turn have deleterious consequences for neuronal viability. These MIA-induced changes may predispose offspring to amygdala-related disorders such as heightened anxiety and depression and also neurodevelopmental disorders, such as autism spectrum disorders.

Minocycline blocks glial cell activation and ventilatory acclimatization to hypoxia.

PubMed

Stokes, Jennifer A; Arbogast, Tara E; Moya, Esteban A; Fu, Zhenxing; Powell, Frank L

2017-04-01

Ventilatory acclimatization to hypoxia (VAH) is the time-dependent increase in ventilation, which persists upon return to normoxia and involves plasticity in both central nervous system respiratory centers and peripheral chemoreceptors. We investigated the role of glial cells in VAH in male Sprague-Dawley rats using minocycline, an antibiotic that inhibits microglia activation and has anti-inflammatory properties, and barometric pressure plethysmography to measure ventilation. Rats received either minocycline (45mg/kg ip daily) or saline beginning 1 day before and during 7 days of chronic hypoxia (CH, Pi O 2  = 70 Torr). Minocycline had no effect on normoxic control rats or the hypercapnic ventilatory response in CH rats, but minocycline significantly ( P < 0.001) decreased ventilation during acute hypoxia in CH rats. However, minocycline administration during only the last 3 days of CH did not reverse VAH. Microglia and astrocyte activation in the nucleus tractus solitarius was quantified from 30 min to 7 days of CH. Microglia showed an active morphology (shorter and fewer branches) after 1 h of hypoxia and returned to the control state (longer filaments and extensive branching) after 4 h of CH. Astrocytes increased glial fibrillary acidic protein antibody immunofluorescent intensity, indicating activation, at both 4 and 24 h of CH. Minocycline had no effect on glia in normoxia but significantly decreased microglia activation at 1 h of CH and astrocyte activation at 24 h of CH. These results support a role for glial cells, providing an early signal for the induction but not maintenance of neural plasticity underlying ventilatory acclimatization to hypoxia. NEW & NOTEWORTHY The signals for neural plasticity in medullary respiratory centers underlying ventilatory acclimatization to chronic hypoxia are unknown. We show that chronic hypoxia activates microglia and subsequently astrocytes. Minocycline, an antibiotic that blocks microglial activation and has anti-inflammatory properties, also blocks astrocyte activation in respiratory centers during chronic hypoxia and ventilatory acclimatization. However, minocycline cannot reverse ventilatory acclimatization after it is established. Hence, glial cells may provide signals that initiate but do not sustain ventilatory acclimatization. Copyright © 2017 the American Physiological Society.

Minocycline blocks glial cell activation and ventilatory acclimatization to hypoxia

PubMed Central

Arbogast, Tara E.; Moya, Esteban A.; Fu, Zhenxing; Powell, Frank L.

2017-01-01

Ventilatory acclimatization to hypoxia (VAH) is the time-dependent increase in ventilation, which persists upon return to normoxia and involves plasticity in both central nervous system respiratory centers and peripheral chemoreceptors. We investigated the role of glial cells in VAH in male Sprague-Dawley rats using minocycline, an antibiotic that inhibits microglia activation and has anti-inflammatory properties, and barometric pressure plethysmography to measure ventilation. Rats received either minocycline (45mg/kg ip daily) or saline beginning 1 day before and during 7 days of chronic hypoxia (CH, PiO2 = 70 Torr). Minocycline had no effect on normoxic control rats or the hypercapnic ventilatory response in CH rats, but minocycline significantly (P < 0.001) decreased ventilation during acute hypoxia in CH rats. However, minocycline administration during only the last 3 days of CH did not reverse VAH. Microglia and astrocyte activation in the nucleus tractus solitarius was quantified from 30 min to 7 days of CH. Microglia showed an active morphology (shorter and fewer branches) after 1 h of hypoxia and returned to the control state (longer filaments and extensive branching) after 4 h of CH. Astrocytes increased glial fibrillary acidic protein antibody immunofluorescent intensity, indicating activation, at both 4 and 24 h of CH. Minocycline had no effect on glia in normoxia but significantly decreased microglia activation at 1 h of CH and astrocyte activation at 24 h of CH. These results support a role for glial cells, providing an early signal for the induction but not maintenance of neural plasticity underlying ventilatory acclimatization to hypoxia. NEW & NOTEWORTHY The signals for neural plasticity in medullary respiratory centers underlying ventilatory acclimatization to chronic hypoxia are unknown. We show that chronic hypoxia activates microglia and subsequently astrocytes. Minocycline, an antibiotic that blocks microglial activation and has anti-inflammatory properties, also blocks astrocyte activation in respiratory centers during chronic hypoxia and ventilatory acclimatization. However, minocycline cannot reverse ventilatory acclimatization after it is established. Hence, glial cells may provide signals that initiate but do not sustain ventilatory acclimatization. PMID:28100653

Astroglial and microglial contributions to iron metabolism disturbance in Parkinson's disease.

PubMed

Song, Ning; Wang, Jun; Jiang, Hong; Xie, Junxia

2018-03-01

Understandings of the disturbed iron metabolism in Parkinson's disease (PD) are largely from the perspectives of neurons. Neurodegenerative processes in PD trigger universal and conserved astroglial dysfunction and microglial activation. In this review, we start with astroglia and microglia in PD with an emphasis on their roles in spreading α-synuclein pathology, and then focus on their contributions in iron metabolism under normal conditions and the diseased state of PD. Elevated iron in the brain regions affects glial features, meanwhile, glial effects on neuronal iron metabolism are largely dependent on their releasing factors. These advances might be valuable for better understanding and modulating iron metabolism disturbance in PD. Copyright © 2018 Elsevier B.V. All rights reserved.

Glial activation and midkine and pleiotrophin transcription in the ventral tegmental area are modulated by morphine administration.

PubMed

García-Pérez, Daniel; Luisa Laorden, M; Núñez, Cristina; Victoria Milanés, M

2014-09-15

Opiates cause persistent restructuring in the mesolimbic reward system. Although a possible role for midkine and pleiotrophin cytokines in the field of synaptic plasticity has been proposed, it has not been assessed whether morphine administration regulates astrogliosis and midkine and pleiotrophin transcription. We observed that single morphine injection and chronic morphine increased glial fibrillary acidic protein expression in the ventral tegmental area (VTA). Interestingly, single morphine injection and chronic morphine increased VTA midkine and pleiotrophin mRNA expression. Given these results, we hypothesize a role for these cytokines in mediating, at least in part, acute neuroprotective effects and chronic neurotrophic adaptations that contribute to drug dependence. Copyright © 2014 Elsevier B.V. All rights reserved.

Neuronal and glial expression of inward rectifier potassium channel subunits Kir2.x in rat dorsal root ganglion and spinal cord.

PubMed

Murata, Yuzo; Yasaka, Toshiharu; Takano, Makoto; Ishihara, Keiko

2016-03-23

Inward rectifier K(+) channels of the Kir2.x subfamily play important roles in controlling the neuronal excitability. Although their cellular localization in the brain has been extensively studied, only a few studies have examined their expression in the spinal cord and peripheral nervous system. In this study, immunohistochemical analyses of Kir2.1, Kir2.2, and Kir2.3 expression were performed in rat dorsal root ganglion (DRG) and spinal cord using bright-field and confocal microscopy. In DRG, most ganglionic neurons expressed Kir2.1, Kir2.2 and Kir2.3, whereas satellite glial cells chiefly expressed Kir2.3. In the spinal cord, Kir2.1, Kir2.2 and Kir2.3 were all expressed highly in the gray matter of dorsal and ventral horns and moderately in the white matter also. Within the gray matter, the expression was especially high in the substantia gelatinosa (lamina II). Confocal images obtained using markers for neuronal cells, NeuN, and astrocytes, Sox9, showed expression of all three Kir2 subunits in both neuronal somata and astrocytes in lamina I-III of the dorsal horn and the lateral spinal nucleus of the dorsolateral funiculus. Immunoreactive signals other than those in neuronal and glial somata were abundant in lamina I and II, which probably located mainly in nerve fibers or nerve terminals. Colocalization of Kir2.1 and 2.3 and that of Kir2.2 and 2.3 were present in neuronal and glial somata. In the ventral horn, motor neurons and interneurons were also immunoreactive with the three Kir2 subunits. Our study suggests that Kir2 channels composed of Kir2.1-2.3 subunits are expressed in neuronal and glial cells in the DRG and spinal cord, contributing to sensory transduction and motor control. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Poly(ADP-ribose) polymerase-1 regulates microglia mediated decrease of endothelial tight junction integrity.

PubMed

Mehrabadi, Abbas Rezaeian; Korolainen, Minna A; Odero, Gary; Miller, Donald W; Kauppinen, Tiina M

2017-09-01

Alzheimer's disease pathology includes, beside neuronal damage, reactive gliosis and reduced blood-brain barrier (BBB) integrity. Microglia are intimately associated with the BBB and upon AD pathology, pro-inflammatory responses of microglia could contribute to BBB damage. To study whether microglia can directly affect BBB integrity, the effects of amyloid beta (Aβ) -stimulated primary murine microglia on co-cultured mouse brain endothelial cells (bEnd3) and murine astrocyte cultures were assessed. We also assessed whether microglial phenotype modulation via poly(ADP-ribose) polymerase-1 (PARP-1) inhibition/ablation can reverse microglial impact on these BBB forming cells. Unstimulated microglia promoted expression of tight junction proteins (TJPs), zonula ocluden-1 (ZO-1) and occludin in co-cultured endothelia cells, whereas Aβ-stimulated microglia reduced endothelial expression of ZO-1 and occludin. Astrocytes co-cultured with microglia showed elevated glial fibrillary acidic protein (GFAP) expression, which was further increased if microglia had been stimulated with Aβ. Aβ induced microglial release of nitric oxide (NO) and tumour necrosis factor alpha (TNFα), which resulted in reduced endothelial expression of TJPs and increased paracellular permeability. Microglial PARP-1 inhibition attenuated these Aβ-induced events. These findings demonstrate that PARP-1 mediated microglial responses (NO and TNFα) can directly reduce BBB integrity by promoting TJP degradation, increasing endothelial cell permeability and inducing astrogliosis. PARP-1 as a modulator of microglial phenotype can prevent microglial BBB damaging events, and thus is a potential therapeutic target. Copyright © 2017 Elsevier Ltd. All rights reserved.