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Sample records for nervous system myelin

  1. Myelin synthesis in the peripheral nervous system.

    PubMed

    Garbay, B; Heape, A M; Sargueil, F; Cassagne, C

    2000-06-01

    By imposing saltatory conduction on the nervous impulse, the principal role of the myelin sheath is to allow the faster propagation of action potentials along the axons which it surrounds. Peripheral nervous system (PNS) myelin is formed by the differentiation of the plasma membrane of Schwann cells. One of the biochemical characteristics that distinguishes myelin from other biological membranes is its high lipid-to-protein ratio. All the major lipid classes are represented in the myelin membrane, while several myelin-specific proteins have been identified. During development, the presence of axons is required for the initiation of myelination, but the nature of the axonal signal is still unknown. The only certainties are that this signal is synthesized by axons whose diameter is greater than 0.7 microm, and that the signal(s) include(s) a diffusible molecule. Morphological studies have provided us with information concerning the timing of myelination, the mechanism by which immature Schwann cells differentiate into a myelinating phenotype and lay down the myelin sheath around the axon, and the accumulation and the structure of the myelin membrane. The last 20 years have seen the identification and the cDNA and gene cloning of the major PNS myelin proteins, which signalled the beginning of the knock-out decade: transgenic null-mutant mice have been created for almost every protein gene. The study of these animals shows that the formation of myelin is considerably less sensitive to molecular alterations than the maintenance of myelin. During the same period, important data has been gathered concerning the synthesis and function of lipids in PNS myelin, although this field has received relatively little attention compared with that of their protein counterparts. PMID:10727776

  2. Signals that initiate myelination in the developing mammalian nervous system.

    PubMed

    Colello, R J; Pott, U

    1997-08-01

    The myelination of axons by oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system is essential for the establishment of saltatory conduction. In the absence or destruction of the myelin sheath, as seen in demyelinating diseases, impulse conduction is impeded resulting in severe sensory and motor deficits. Axon myelination is the culmination of a sequence of events that begins with the differentiation of glial cells and proceeds to the transcription and translation of myelin genes, the elaboration of a myelin sheath, and the recognition and ensheathment of axons. This review examines the regulatory mechanisms for each of these steps and compares and contrasts the role of the axon in initiating myelination in the central and peripheral nervous system. PMID:9396006

  3. Review: Glial lineages and myelination in the central nervous system

    PubMed Central

    COMPSTON, ALASTAIR; ZAJICEK, JOHN; SUSSMAN, JON; WEBB, ANNA; HALL, GILLIAN; MUIR, DAVID; SHAW, CHRISTOPHER; WOOD, ANDREW; SCOLDING, NEIL

    1997-01-01

    Oligodendrocytes, derived from stem cell precursors which arise in subventricular zones of the developing central nervous system, have as their specialist role the synthesis and maintenance of myelin. Astrocytes contribute to the cellular architecture of the central nervous system and act as a source of growth factors and cytokines; microglia are bone-marrow derived macrophages which function as primary immunocompetent cells in the central nervous system. Myelination depends on the establishment of stable relationships between each differentiated oligodendrocyte and short segments of several neighbouring axons. There is growing evidence, especially from studies of glial cell implantation, that oligodendrocyte precursors persist in the adult nervous system and provide a limited capacity for the restoration of structure and function in myelinated pathways damaged by injury or disease. PMID:9061442

  4. Molecular mechanisms regulating myelination in the peripheral nervous system.

    PubMed

    Pereira, Jorge A; Lebrun-Julien, Frédéric; Suter, Ueli

    2012-02-01

    Glial cells and neurons are engaged in a continuous and highly regulated bidirectional dialog. A remarkable example is the control of myelination. Oligodendrocytes in the central nervous system (CNS) and Schwann cells (SCs) in the peripheral nervous system (PNS) wrap their plasma membranes around axons to organize myelinated nerve fibers that allow rapid saltatory conduction. The functionality of this system is critical, as revealed by numerous neurological diseases that result from deregulation of the system, including multiple sclerosis and peripheral neuropathies. In this review we focus on PNS myelination and present a conceptual framework that integrates crucial signaling mechanisms with basic SC biology. We will highlight signaling hubs and overarching molecular mechanisms, including genetic, epigenetic, and post-translational controls, which together regulate the interplay between SCs and axons, extracellular signals, and the transcriptional network. PMID:22192173

  5. Progesterone Synthesis in the Nervous System: Implications for Myelination and Myelin Repair

    PubMed Central

    Schumacher, Michael; Hussain, Rashad; Gago, Nathalie; Oudinet, Jean-Paul; Mattern, Claudia; Ghoumari, Abdel M.

    2011-01-01

    Progesterone is well known as a female reproductive hormone and in particular for its role in uterine receptivity, implantation, and the maintenance of pregnancy. However, neuroendocrine research over the past decades has established that progesterone has multiple functions beyond reproduction. Within the nervous system, its neuromodulatory and neuroprotective effects are much studied. Although progesterone has been shown to also promote myelin repair, its influence and that of other steroids on myelination and remyelination is relatively neglected. Reasons for this are that hormonal influences are still not considered as a central problem by most myelin biologists, and that neuroendocrinologists are not sufficiently concerned with the importance of myelin in neuron functions and viability. The effects of progesterone in the nervous system involve a variety of signaling mechanisms. The identification of the classical intracellular progesterone receptors as therapeutic targets for myelin repair suggests new health benefits for synthetic progestins, specifically designed for contraceptive use and hormone replacement therapies. There are also major advantages to use natural progesterone in neuroprotective and myelin repair strategies, because progesterone is converted to biologically active metabolites in nervous tissues and interacts with multiple target proteins. The delivery of progesterone however represents a challenge because of its first-pass metabolism in digestive tract and liver. Recently, the intranasal route of progesterone administration has received attention for easy and efficient targeting of the brain. Progesterone in the brain is derived from the steroidogenic endocrine glands or from local synthesis by neural cells. Stimulating the formation of endogenous progesterone is currently explored as an alternative strategy for neuroprotection, axonal regeneration, and myelin repair. PMID:22347156

  6. Data supporting the role of Fyn in initiating myelination in the peripheral nervous system.

    PubMed

    Miyamoto, Yuki; Tamano, Moe; Torii, Tomohiro; Kawahara, Kazuko; Nakamura, Kazuaki; Tanoue, Akito; Takada, Shuji; Yamauchi, Junji

    2016-06-01

    Transgenic mice, which express active Fyn tyrosine kinase under the control of a glial fibrillary acidic protein promoter, have been produced. This promoter induces protein expression in the initiation stage of myelination in the peripheral nervous system (PNS) "Phosphorylation of cytohesin-1 by Fyn is required for initiation of myelination and the extent of myelination during development (Yamauchi et al., 2015 [1])". Herein we provide the data regarding myelination-related protein markers and myelin ultrastructure in transgenic mice. PMID:27115022

  7. Data supporting the role of Fyn in initiating myelination in the peripheral nervous system

    PubMed Central

    Miyamoto, Yuki; Tamano, Moe; Torii, Tomohiro; Kawahara, Kazuko; Nakamura, Kazuaki; Tanoue, Akito; Takada, Shuji; Yamauchi, Junji

    2016-01-01

    Transgenic mice, which express active Fyn tyrosine kinase under the control of a glial fibrillary acidic protein promoter, have been produced. This promoter induces protein expression in the initiation stage of myelination in the peripheral nervous system (PNS) “Phosphorylation of cytohesin-1 by Fyn is required for initiation of myelination and the extent of myelination during development (Yamauchi et al., 2015 [1])”. Herein we provide the data regarding myelination-related protein markers and myelin ultrastructure in transgenic mice. PMID:27115022

  8. Septin/anillin filaments scaffold central nervous system myelin to accelerate nerve conduction.

    PubMed

    Patzig, Julia; Erwig, Michelle S; Tenzer, Stefan; Kusch, Kathrin; Dibaj, Payam; Möbius, Wiebke; Goebbels, Sandra; Schaeren-Wiemers, Nicole; Nave, Klaus-Armin; Werner, Hauke B

    2016-01-01

    Myelination of axons facilitates rapid impulse propagation in the nervous system. The axon/myelin-unit becomes impaired in myelin-related disorders and upon normal aging. However, the molecular cause of many pathological features, including the frequently observed myelin outfoldings, remained unknown. Using label-free quantitative proteomics, we find that the presence of myelin outfoldings correlates with a loss of cytoskeletal septins in myelin. Regulated by phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2)-levels, myelin septins (SEPT2/SEPT4/SEPT7/SEPT8) and the PI(4,5)P2-adaptor anillin form previously unrecognized filaments that extend longitudinally along myelinated axons. By confocal microscopy and immunogold-electron microscopy, these filaments are localized to the non-compacted adaxonal myelin compartment. Genetic disruption of these filaments in Sept8-mutant mice causes myelin outfoldings as a very specific neuropathology. Septin filaments thus serve an important function in scaffolding the axon/myelin-unit, evidently a late stage of myelin maturation. We propose that pathological or aging-associated diminishment of the septin/anillin-scaffold causes myelin outfoldings that impair the normal nerve conduction velocity. PMID:27504968

  9. Septin/anillin filaments scaffold central nervous system myelin to accelerate nerve conduction

    PubMed Central

    Patzig, Julia; Erwig, Michelle S; Tenzer, Stefan; Kusch, Kathrin; Dibaj, Payam; Möbius, Wiebke; Goebbels, Sandra; Schaeren-Wiemers, Nicole; Nave, Klaus-Armin; Werner, Hauke B

    2016-01-01

    Myelination of axons facilitates rapid impulse propagation in the nervous system. The axon/myelin-unit becomes impaired in myelin-related disorders and upon normal aging. However, the molecular cause of many pathological features, including the frequently observed myelin outfoldings, remained unknown. Using label-free quantitative proteomics, we find that the presence of myelin outfoldings correlates with a loss of cytoskeletal septins in myelin. Regulated by phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2)-levels, myelin septins (SEPT2/SEPT4/SEPT7/SEPT8) and the PI(4,5)P2-adaptor anillin form previously unrecognized filaments that extend longitudinally along myelinated axons. By confocal microscopy and immunogold-electron microscopy, these filaments are localized to the non-compacted adaxonal myelin compartment. Genetic disruption of these filaments in Sept8-mutant mice causes myelin outfoldings as a very specific neuropathology. Septin filaments thus serve an important function in scaffolding the axon/myelin-unit, evidently a late stage of myelin maturation. We propose that pathological or aging-associated diminishment of the septin/anillin-scaffold causes myelin outfoldings that impair the normal nerve conduction velocity. DOI: http://dx.doi.org/10.7554/eLife.17119.001 PMID:27504968

  10. The Polarity Protein Scribble Regulates Myelination and Remyelination in the Central Nervous System

    PubMed Central

    Jarjour, Andrew A.; Boyd, Amanda; Dow, Lukas E.; Holloway, Rebecca K.; Goebbels, Sandra; Humbert, Patrick O.; Williams, Anna; ffrench-Constant, Charles

    2015-01-01

    The development and regeneration of myelin by oligodendrocytes, the myelin-forming cells of the central nervous system (CNS), requires profound changes in cell shape that lead to myelin sheath initiation and formation. Here, we demonstrate a requirement for the basal polarity complex protein Scribble in CNS myelination and remyelination. Scribble is expressed throughout oligodendroglial development and is up-regulated in mature oligodendrocytes where it is localised to both developing and mature CNS myelin sheaths. Knockdown of Scribble expression in cultured oligodendroglia results in disrupted morphology and myelination initiation. When Scribble expression is conditionally eliminated in the myelinating glia of transgenic mice, myelin initiation in CNS is disrupted, both during development and following focal demyelination, and longitudinal extension of the myelin sheath is disrupted. At later stages of myelination, Scribble acts to negatively regulate myelin thickness whilst suppressing the extracellular signal-related kinase (ERK)/mitogen-activated protein kinase (MAP) kinase pathway, and localises to non-compact myelin flanking the node of Ranvier where it is required for paranodal axo-glial adhesion. These findings demonstrate an essential role for the evolutionarily-conserved regulators of intracellular polarity in myelination and remyelination. PMID:25807062

  11. The polarity protein Scribble regulates myelination and remyelination in the central nervous system.

    PubMed

    Jarjour, Andrew A; Boyd, Amanda; Dow, Lukas E; Holloway, Rebecca K; Goebbels, Sandra; Humbert, Patrick O; Williams, Anna; ffrench-Constant, Charles

    2015-03-01

    The development and regeneration of myelin by oligodendrocytes, the myelin-forming cells of the central nervous system (CNS), requires profound changes in cell shape that lead to myelin sheath initiation and formation. Here, we demonstrate a requirement for the basal polarity complex protein Scribble in CNS myelination and remyelination. Scribble is expressed throughout oligodendroglial development and is up-regulated in mature oligodendrocytes where it is localised to both developing and mature CNS myelin sheaths. Knockdown of Scribble expression in cultured oligodendroglia results in disrupted morphology and myelination initiation. When Scribble expression is conditionally eliminated in the myelinating glia of transgenic mice, myelin initiation in CNS is disrupted, both during development and following focal demyelination, and longitudinal extension of the myelin sheath is disrupted. At later stages of myelination, Scribble acts to negatively regulate myelin thickness whilst suppressing the extracellular signal-related kinase (ERK)/mitogen-activated protein kinase (MAP) kinase pathway, and localises to non-compact myelin flanking the node of Ranvier where it is required for paranodal axo-glial adhesion. These findings demonstrate an essential role for the evolutionarily-conserved regulators of intracellular polarity in myelination and remyelination. PMID:25807062

  12. The transcriptome of mouse central nervous system myelin

    PubMed Central

    Thakurela, Sudhir; Garding, Angela; Jung, Ramona B.; Müller, Christina; Goebbels, Sandra; White, Robin; Werner, Hauke B.; Tiwari, Vijay K.

    2016-01-01

    Rapid nerve conduction in the CNS is facilitated by insulation of axons with myelin, a specialized oligodendroglial compartment distant from the cell body. Myelin is turned over and adapted throughout life; however, the molecular and cellular basis of myelin dynamics remains elusive. Here we performed a comprehensive transcriptome analysis (RNA-seq) of myelin biochemically purified from mouse brains at various ages and find a surprisingly large pool of transcripts enriched in myelin. Further computational analysis showed that the myelin transcriptome is closely related to the myelin proteome but clearly distinct from the transcriptomes of oligodendrocytes and brain tissues, suggesting a highly selective incorporation of mRNAs into the myelin compartment. The mRNA-pool in myelin displays maturation-dependent dynamic changes of composition, abundance, and functional associations; however ageing-dependent changes after 6 months were minor. We suggest that this transcript pool enables myelin turnover and the local adaptation of individual pre-existing myelin sheaths. PMID:27173133

  13. The transcriptome of mouse central nervous system myelin.

    PubMed

    Thakurela, Sudhir; Garding, Angela; Jung, Ramona B; Müller, Christina; Goebbels, Sandra; White, Robin; Werner, Hauke B; Tiwari, Vijay K

    2016-01-01

    Rapid nerve conduction in the CNS is facilitated by insulation of axons with myelin, a specialized oligodendroglial compartment distant from the cell body. Myelin is turned over and adapted throughout life; however, the molecular and cellular basis of myelin dynamics remains elusive. Here we performed a comprehensive transcriptome analysis (RNA-seq) of myelin biochemically purified from mouse brains at various ages and find a surprisingly large pool of transcripts enriched in myelin. Further computational analysis showed that the myelin transcriptome is closely related to the myelin proteome but clearly distinct from the transcriptomes of oligodendrocytes and brain tissues, suggesting a highly selective incorporation of mRNAs into the myelin compartment. The mRNA-pool in myelin displays maturation-dependent dynamic changes of composition, abundance, and functional associations; however ageing-dependent changes after 6 months were minor. We suggest that this transcript pool enables myelin turnover and the local adaptation of individual pre-existing myelin sheaths. PMID:27173133

  14. Hedgehog signaling regulates myelination in the peripheral nervous system through primary cilia.

    PubMed

    Yoshimura, Kentaro; Takeda, Sen

    2012-02-01

    Myelination is an essential prerequisite for the nervous system to transmit an impulse efficiently by a saltatory conduction. In the peripheral nervous system (PNS), Schwann cells (SCs) engage in myelination. However, a detailed molecular mechanism underlying myelination still remains unclear. In this study, we hypothesized that the primary cilia of SCs are the regulators of Hedgehog (Hh) signaling-mediated myelination. To confirm our hypothesis, we used mouse dorsal root ganglion (DRG)/SC co-cultures, wherein the behavior of SCs could be analyzed by maintaining the interaction of SCs with DRG neurons. Under these conditions, SCs had primary cilia, and Hh signaling molecules accumulated on the primary cilia. When the SCs were stimulated by the addition of desert hedgehog or smoothened agonist, formation of myelin segments on the DRG axons was facilitated. On the contrary, upon administration of cyclopamine, an inhibitor of Hh signaling, myelin segments became comparable to those of controls. Of note, the ratio of SCs harboring primary cilium reached the highest point during the early phase of myelination. Furthermore, the strongest effects of Hh on myelination were encountered during the same stage. These results collectively indicate that Hh signaling regulates myelin formation through primary cilia in the PNS. PMID:22101064

  15. Induction of myelination in the central nervous system by electrical activity.

    PubMed Central

    Demerens, C; Stankoff, B; Logak, M; Anglade, P; Allinquant, B; Couraud, F; Zalc, B; Lubetzki, C

    1996-01-01

    The oligodendrocyte is the myelin-forming cell in the central nervous system. Despite the close interaction between axons and oligodendrocytes, there is little evidence that neurons influence myelinogenesis. On the contrary, newly differentiated oligodendrocytes, which mature in culture in the total absence of neurons, synthesize the myelin-specific constituents of oligodendrocytes differentiated in vivo and even form myelin-like figures. Neuronal electrical activity may be required, however, for the appropriate formation of the myelin sheath. To investigate the role of electrical activity on myelin formation, we have used highly specific neurotoxins, which can either block (tetrodotoxin) or increase (alpha-scorpion toxin) the firing of neurons. We show that myelination can be inhibited by blocking the action potential of neighboring axons or enhanced by increasing their electrical activity, clearly linking neuronal electrical activity to myelinogenesis. Images Fig. 1 Fig. 2 Fig. 3 PMID:8790426

  16. Human central nervous system myelin inhibits neurite outgrowth.

    PubMed

    Ng, W P; Cartel, N; Roder, J; Roach, A; Lozano, A

    1996-05-13

    In vitro and animal studies have identified molecules in mammalian CNS myelin which inhibit neuritic extension and which may be responsible, at least in part, for the lack of axonal regeneration after injury in the injured brain, optic nerve and spinal cord. To determine whether such inhibitory activity may be present in human CNS myelin, we used a bioassay to characterize neurite outgrowth on this substrate. Human CNS myelin strongly inhibited neuritic outgrowth from newborn rat dorsal root ganglion neurons and NG-108-15 cells, a neuroblastoma-glioma hybrid cell line. Similar but less potent inhibitory activity was identified in human gray matter. The CNS myelin inhibition of neuritic outgrowth appeared to be dependent on direct contact between the myelin substrate and neurites. The inhibitory activity in human CNS myelin closely resembled that described in adult rodents. Inhibition of neurite growth by human CNS myelin in this in vitro bioassay mirrors the lack of regeneration in vivo and can be used as a model to develop strategies designed to enhance axonal regeneration and neural recovery. PMID:8782892

  17. Galactosphingolipids and axono-glial interaction in myelin of the central nervous system.

    PubMed

    Bosio, A; Büssow, H; Adam, J; Stoffel, W

    1998-05-01

    The myelin of central and peripheral nervous system of UDP-galactose-ceramide galactosyltransferase deficient mice (cgt-/-) is completely depleted of its major lipid constituents, galactocerebrosides and sulfatides. The deficiency of these glycolipids affects the biophysical properties of the myelin sheath and causes the loss of the rapid saltatory conduction velocity of myelinated axons. With the onset of myelination, null mutant cgt-/- mice develop fatal neurological defects. CNS and PNS analysis of cgt-/- mice revealed (1) hypomyelination of axons of the spinal cord and optic nerves, but no apoptosis of oligodendrocytes, (2) redundant myelin in younger mice leading to vacuolated nerve fibers in cgt-/- mice, (3) the occurrence of multiple myelinated CNS axons, and (4) severely distorted lateral loops in CNS paranodes. The loss of saltatory conduction is not associated with a randomization of voltage-gated sodium channels in the axolemma of PNS fibers. We conclude that cerebrosides (GalC) and sulfatides (sGalC) play a major role in CNS axono-glial interaction. A close axono-glial contact is not a prerequisite for the spiraling and compaction process of myelin. Axonal sodium channels remain clustered at the nodes of Ranvier independent of the change in the physical properties of myelin membrane devoid of galactosphingolipids. Increased intracellular concentrations of free ceramides do not trigger apoptosis of oligodendrocytes. PMID:9560463

  18. Molecular domains of myelinated axons in the peripheral nervous system.

    PubMed

    Salzer, James L; Brophy, Peter J; Peles, Elior

    2008-11-01

    Myelinated axons are organized into a series of specialized domains with distinct molecular compositions and functions. These domains, which include the node of Ranvier, the flanking paranodal junctions, the juxtaparanodes, and the internode, form as the result of interactions with myelinating Schwann cells. This domain organization is essential for action potential propagation by saltatory conduction and for the overall function and integrity of the axon. PMID:18803321

  19. The role of myelin in Theiler's virus persistence in the central nervous system.

    PubMed

    Roussarie, Jean-Pierre; Ruffié, Claude; Brahic, Michel

    2007-02-01

    Theiler's virus, a picornavirus, persists for life in the central nervous system of mouse and causes a demyelinating disease that is a model for multiple sclerosis. The virus infects neurons first but persists in white matter glial cells, mainly oligodendrocytes and macrophages. The mechanism, by which the virus traffics from neurons to glial cells, and the respective roles of oligodendrocytes and macrophages in persistence are poorly understood. We took advantage of our previous finding that the shiverer mouse, a mutant with a deletion in the myelin basic protein gene (Mbp), is resistant to persistent infection to examine the role of myelin in persistence. Using immune chimeras, we show that resistance is not mediated by immune responses or by an efficient recruitment of inflammatory cells into the central nervous system. With both in vivo and in vitro experiments, we show that the mutation does not impair the permissiveness of neurons, oligodendrocytes, and macrophages to the virus. We demonstrate that viral antigens are present in cytoplasmic channels of myelin during persistent infection of wild-type mice. Using the optic nerve as a model, we show that the virus traffics from the axons of retinal ganglion cells to the cytoplasmic channels of myelin, and that this traffic is impaired by the shiverer mutation. These results uncover an unsuspected axon to myelin traffic of Theiler's virus and the essential role played by the infection of myelin/oligodendrocyte in persistence. PMID:17305428

  20. The Lin28/let-7 axis is critical for myelination in the peripheral nervous system

    PubMed Central

    Gökbuget, Deniz; Pereira, Jorge A.; Bachofner, Sven; Marchais, Antonin; Ciaudo, Constance; Stoffel, Markus; Schulte, Johannes H.; Suter, Ueli

    2015-01-01

    MicroRNAs (miRNAs) are crucial regulators of myelination in the peripheral nervous system (PNS). However, the miRNAs species involved and the underlying mechanisms are largely unknown. We found that let-7 miRNAs are highly abundant during PNS myelination and that their levels are inversely correlated to the expression of lin28 homolog B (Lin28B), an antagonist of let-7 accumulation. Sustained expression of Lin28B and consequently reduced levels of let-7 miRNAs results in a failure of Schwann cell myelination in transgenic mouse models and in cell culture. Subsequent analyses revealed that let-7 miRNAs promote expression of the myelination-driving master transcription factor Krox20 (also known as Egr2) through suppression of myelination inhibitory Notch signalling. We conclude that the Lin28B/let-7 axis acts as a critical driver of PNS myelination, in particular by regulating myelination onset, identifying this pathway also as a potential therapeutic target in demyelinating diseases. PMID:26466203

  1. The Lin28/let-7 axis is critical for myelination in the peripheral nervous system.

    PubMed

    Gökbuget, Deniz; Pereira, Jorge A; Bachofner, Sven; Marchais, Antonin; Ciaudo, Constance; Stoffel, Markus; Schulte, Johannes H; Suter, Ueli

    2015-01-01

    MicroRNAs (miRNAs) are crucial regulators of myelination in the peripheral nervous system (PNS). However, the miRNAs species involved and the underlying mechanisms are largely unknown. We found that let-7 miRNAs are highly abundant during PNS myelination and that their levels are inversely correlated to the expression of lin28 homolog B (Lin28B), an antagonist of let-7 accumulation. Sustained expression of Lin28B and consequently reduced levels of let-7 miRNAs results in a failure of Schwann cell myelination in transgenic mouse models and in cell culture. Subsequent analyses revealed that let-7 miRNAs promote expression of the myelination-driving master transcription factor Krox20 (also known as Egr2) through suppression of myelination inhibitory Notch signalling. We conclude that the Lin28B/let-7 axis acts as a critical driver of PNS myelination, in particular by regulating myelination onset, identifying this pathway also as a potential therapeutic target in demyelinating diseases. PMID:26466203

  2. Selective and antigen-dependent effects of myelin degeneration on central nervous system inflammation.

    PubMed

    Aboul-Enein, Fahmy; Bauer, Jan; Klein, Matthias; Schubart, Anna; Flügel, Alexander; Ritter, Thomas; Kawakami, Naoto; Siedler, Frank; Linington, Christopher; Wekerle, Hartmut; Lassmann, Hans; Bradl, Monika

    2004-12-01

    Damage to myelin sheath or oligodendrocytes may precede or even provoke inflammation of the central nervous system (CNS), but the extent to which these degenerative changes affect inflammation remains largely undefined. To study these processes in more detail, we used CNS antigen-specific T cells in the presence or absence of anti-myelin antibodies to induce experimental autoimmune encephalomyelitis (EAE) in transgenic Lewis rats with low-grade subclinical myelin degeneration and associated microglia cell activation, and in wild-type Lewis rats with an intact CNS. We found that myelin degeneration affects the localization of inflammatory lesions, the numbers of T cells recruited to these lesions, and the severity of the resulting clinical disease. In addition, myelin degeneration and associated microglia cell activation jointly enhance the susceptibility of the CNS to the action of anti-myelin antibodies. Our data show that even subtle alterations of myelin and oligodendrocytes may massively amplify the extent of demyelination and tissue damage, involving different immune effector mechanisms. A similar causal relationship might also operate in human patients with multiple sclerosis, where T cell-mediated inflammation and antibody-mediated demyelination have been documented, and where genetic factors might determine the susceptibility of the target tissue for immune-mediated injury. PMID:15624765

  3. A model of tight junction function in central nervous system myelinated axons.

    PubMed

    Gow, Alexander; Devaux, Jerome

    2008-11-01

    The insulative properties of myelin sheaths in the central and peripheral nervous systems (CNS and PNS) are widely thought to derive from the high resistance and low capacitance of the constituent membranes. Although this view adequately accounts for myelin function in large diameter fibers, it poorly reflects the behavior of small fibers that are prominent in many regions of the CNS. Herein, we develop a computational model to more accurately represent conduction in small fibers. By incorporating structural features that, hitherto, have not been simulated, we demonstrate that myelin tight junctions (TJs) improve saltatory conduction by reducing current flow through the myelin, limiting axonal membrane depolarization and restraining the activation of ion channels beneath the myelin sheath. Accordingly, our simulations provide a novel view of myelin by which TJs minimize charging of the membrane capacitance and lower the membrane time constant to improve the speed and accuracy of transmission in small diameter fibers. This study establishes possible mechanisms whereby TJs affect conduction in the absence of overt perturbations to myelin architecture and may in part explain the tremor and gait abnormalities observed in Claudin 11-null mice. PMID:20102674

  4. The intrinsic fluorescence of isolated central-nervous-system myelin-sheath preparations.

    PubMed Central

    Crang, A J; Rumsby, M G

    1979-01-01

    The intrinsic fluorescence characteristics of tyrosine and tryptophan residues in the proteins of isolated central-nervous-system myelin were investigated to gain information concerning the location of these residues within the intact membrane system. Tryptophan fluorescence from isolated myelin has an emission maximum at 325 nm that appears to arise from at least two different populations of tryptophan residues. Further evidence for heterogeneity of tryptophan location in the membrane is obtained from quenching studies with chloroform and acrylamide. It is speculated that one tryptophan population is hydrophobically situated and may be derived from the proteolipid protein of myelin, whereas the other tryptophan population is located at the membrane surface and may arise from the extrinsic basic protein. A significant tyrosine fluorescence is detected from isolated myelin, indicating that some of these residues are not quenched by structural interactions within the lipid--protein membrane system. Studies with freeze-dried resuspended myelin suggest that the structural arrangement of protein components in the dried rehydrated membrane system differs significantly from that of the freshly isolated myelin membrane. PMID:435264

  5. Actin filament turnover drives leading edge growth during myelin sheath formation in the central nervous system

    PubMed Central

    Schmitt, Sebastian; Snaidero, Nicolas; Mitkovski, Mišo; Velte, Caroline; Brückner, Bastian R.; Alexopoulos, Ioannis; Czopka, Tim; Jung, Sang Y.; Rhee, Jeong S.; Janshoff, Andreas; Witke, Walter; Schaap, Iwan A.T.; Lyons, David A.; Simons, Mikael

    2016-01-01

    Summary During central nervous system development, oligodendrocytes wrap their plasma membrane around axons to generate multi-lamellar myelin sheaths. To drive growth at the leading edge of myelin at the interface with the axon, mechanical forces are necessary, but the underlying mechanisms are not known. Using an interdisciplinary approach that combines morphological, genetic and biophysical analyses, we identified a key role for actin filament network turnover in myelin growth. At the onset of myelin biogenesis, F-actin is redistributed to the leading edge, where its polymerization-based forces push out non-adhesive and motile protrusions. F-actin disassembly converts protrusions into sheets by reducing surface tension and in turn inducing membrane spreading and adhesion. We identified the actin depolymerizing factor ADF/Cofilin1, which mediates high F-actin turnover rates, as essential factor in this process. We propose that F-actin turnover is the driving force in myelin wrapping by regulating repetitive cycles of leading edge protrusion and spreading. PMID:26166299

  6. MicroRNA-23a promotes myelination in the central nervous system.

    PubMed

    Lin, Shu-Ting; Huang, Yong; Zhang, Luoying; Heng, Mary Y; Ptácek, Louis J; Fu, Ying-Hui

    2013-10-22

    Demyelinating disorders including leukodystrophies are devastating conditions that are still in need of better understanding, and both oligodendrocyte differentiation and myelin synthesis pathways are potential avenues for developing treatment. Overexpression of lamin B1 leads to leukodystrophy characterized by demyelination of the central nervous system, and microRNA-23 (miR-23) was found to suppress lamin B1 and enhance oligodendrocyte differentiation in vitro. Here, we demonstrated that miR-23a-overexpressing mice have increased myelin thickness, providing in vivo evidence that miR-23a enhances both oligodendrocyte differentiation and myelin synthesis. Using this mouse model, we explored possible miR-23a targets and revealed that the phosphatase and tensin homologue/phosphatidylinositol trisphosphate kinase/Akt/mammalian target of rapamycin pathway is modulated by miR-23a. Additionally, a long noncoding RNA, 2700046G09Rik, was identified as a miR-23a target and modulates phosphatase and tensin homologue itself in a miR-23a-dependent manner. The data presented here imply a unique role for miR-23a in the coordination of proteins and noncoding RNAs in generating and maintaining healthy myelin. PMID:24101522

  7. Osteodysplastic primordial dwarfism type II with normal intellect but delayed central nervous system myelination.

    PubMed

    Halder, A; Pahi, J; Sharma, A K; Bhatia, V L; Phadke, R V; Gujral, R; Agarwal, S S

    1998-10-30

    We describe a 7-year-boy with severe prenatal and postnatal growth retardation, skeletal changes, normal intellect, and unusual facial appearance. The skeletal changes are suggestive of osteodysplastic primordial dwarfism type II (OPD II). He is the first patient of this kind from the Indian subcontinent and the 18th to be reported, based on a literature search (MEDLINE; 1982 to April 1997). He also represents the first case of OPD-II with normal intellect but delayed central nervous system myelination. PMID:9800906

  8. Myocilin mediates myelination in the peripheral nervous system through ErbB2/3 signaling.

    PubMed

    Kwon, Heung Sun; Johnson, Thomas V; Joe, Myung Kuk; Abu-Asab, Mones; Zhang, Jun; Chan, Chi Chao; Tomarev, Stanislav I

    2013-09-13

    The glaucoma-associated gene, myocilin, is expressed in ocular and non-ocular tissues including the peripheral nervous system, but its functions in these tissues remain poorly understood. We demonstrate that in sciatic nerve, myocilin is expressed in Schwann cells with high concentrations at the nodes of Ranvier. There, myocilin interacts with gliomedin, neurofascin, and NrCAM, which are essential for node formation and function. Treatment of isolated dorsal root ganglion cultures with myocilin stimulates clustering of the nodal proteins neurofascin and sodium channel Nav1.2. Sciatic nerves of myocilin null mice express reduced levels of several myelin-associated and basal membrane proteins compared with those of wild-type littermates. They also demonstrate reduced myelin sheath thickness and partial disorganization of the nodes. Myocilin signaling through ErbB2/3 receptors may contribute to these observed effects. Myocilin binds to ErbB2/ErbB3, activates these receptors, and affects the downstream PI3K-AKT signaling pathway. These data implicate a role for myocilin in the development and/or maintenance of myelination and nodes of Ranvier in sciatic nerve. PMID:23897819

  9. Signaling through ERK1/2 controls myelin thickness during myelin repair in the adult central nervous system.

    PubMed

    Fyffe-Maricich, Sharyl L; Schott, Alexandra; Karl, Molly; Krasno, Janet; Miller, Robert H

    2013-11-20

    Oligodendrocytes, the myelin-forming cells of the CNS, exquisitely tailor the thickness of individual myelin sheaths to the diameter of their target axons to maximize the speed of action potential propagation, thus ensuring proper neuronal connectivity and function. Following demyelinating injuries to the adult CNS, newly formed oligodendrocytes frequently generate new myelin sheaths. Following episodes of demyelination such as those that occur in patients with multiple sclerosis, however, the matching of myelin thickness to axon diameter fails leaving remyelinated axons with thin myelin sheaths potentially compromising function and leaving axons vulnerable to damage. How oligodendrocytes determine the appropriate thickness of myelin for an axon of defined size during repair is unknown and identifying the signals that regulate myelin thickness has obvious therapeutic implications. Here, we show that sustained activation of extracellular-regulated kinases 1 and 2 (ERK1/2) in oligodendrocyte lineage cells results in accelerated myelin repair after injury, and is sufficient for the generation of thick myelin sheaths around remyelinated axons in the adult mouse spinal cord. Our findings suggest a model where ERK1/2 MAP kinase signaling acts as a myelin thickness rheostat that instructs oligodendrocytes to generate axon-appropriate quantities of myelin. PMID:24259565

  10. A critical role for the cholesterol-associated proteolipids PLP and M6B in myelination of the central nervous system.

    PubMed

    Werner, Hauke B; Krämer-Albers, Eva-Maria; Strenzke, Nicola; Saher, Gesine; Tenzer, Stefan; Ohno-Iwashita, Yoshiko; De Monasterio-Schrader, Patricia; Möbius, Wiebke; Moser, Tobias; Griffiths, Ian R; Nave, Klaus-Armin

    2013-04-01

    The formation of central nervous system myelin by oligodendrocytes requires sterol synthesis and is associated with a significant enrichment of cholesterol in the myelin membrane. However, it is unknown how oligodendrocytes concentrate cholesterol above the level found in nonmyelin membranes. Here, we demonstrate a critical role for proteolipids in cholesterol accumulation. Mice lacking the most abundant myelin protein, proteolipid protein (PLP), are fully myelinated, but PLP-deficient myelin exhibits a reduced cholesterol content. We therefore hypothesized that "high cholesterol" is not essential in the myelin sheath itself but is required for an earlier step of myelin biogenesis that is fully compensated for in the absence of PLP. We also found that a PLP-homolog, glycoprotein M6B, is a myelin component of low abundance. By targeting the Gpm6b-gene and crossbreeding, we found that single-mutant mice lacking either PLP or M6B are fully myelinated, while double mutants remain severely hypomyelinated, with enhanced neurodegeneration and premature death. As both PLP and M6B bind membrane cholesterol and associate with the same cholesterol-rich oligodendroglial membrane microdomains, we suggest a model in which proteolipids facilitate myelination by sequestering cholesterol. While either proteolipid can maintain a threshold level of cholesterol in the secretory pathway that allows myelin biogenesis, lack of both proteolipids results in a severe molecular imbalance of prospective myelin membrane. However, M6B is not efficiently sorted into mature myelin, in which it is 200-fold less abundant than PLP. Thus, only PLP contributes to the high cholesterol content of myelin by association and co-transport. PMID:23322581

  11. Molecular anatomy and genetics of myelin proteins in the peripheral nervous system.

    PubMed Central

    Snipes, G J; Suter, U

    1995-01-01

    Myelin contains a number of proteins, the major examples of which are protein zero (Po), P2 protein, peripheral myelin protein 22 (PMP22), myelin basic proteins (MBPs), myelin-associated glycoprotein (MAG) and the recently described connexin 32 (Cx32). This list is probably still incomplete. The localisation and possible functions of these proteins are reviewed. In the past few years a number of inherited demyelinating neuropathies in mice and the human have been shown to be due to mutations affecting the genes PMP22, Po and Cx32 so that it has become possible to characterise the molecular pathology of the majority of these disorders. This has provided important insights into the relationships between the structure of myelin and the function of its constituent proteins. Images Fig. 1 PMID:7559122

  12. Schwann cell invasion of the central nervous system of the myelin mutants

    PubMed Central

    DUNCAN, I. D.; HOFFMAN, R. L.

    1997-01-01

    Schwann cells are excluded from the CNS during development by the glial limiting membrane, an area of astrocytic specialisation present at the nerve root transitional zone, and at blood vessels in the neuropil. This barrier, however, can be disrupted and, with the highly migratory nature of Schwann cells, can result in their invasion and myelination of the CNS in many pathological situations. In this paper we demonstrate that this occurs in a number of myelin mutants, including the myelin deficient (md) and taiep rats and the canine shaking (sh) pup. While it is still relatively uncommon in the rodent mutants, the sh pup shows extensive Schwann cell invasion along the neuraxis. This invasion involves the spinal cord, brain stem, and cerebellum and increases in amount and distribution with age. In situ hybridisation studies using a P0 riboprobe suggest that the likely origin of these cells in the sh pup is the nerve roots, primarily the dorsal roots. Paradoxically, Schwann cell myelination of the CNS increases with time in the sh pup despite a marked, progressive gliosis involving the glia limitans and neuropil. Thus the mechanism by which these cells migrate into the CNS through the gliosed nerve root transitional zone or from vasa nervorum remains unknown. Extensive Schwann cell CNS myelination may have therapeutic significance in human myelin disease. PMID:9034880

  13. Myelin Oligodendrocyte Glycoprotein-Associated Pediatric Central Nervous System Demyelination: Clinical Course, Neuroimaging Findings, and Response to Therapy.

    PubMed

    Thulasirajah, Salini; Pohl, Daniela; Davila-Acosta, Jorge; Venkateswaran, Sunita

    2016-08-01

    Under the umbrella of pediatric-acquired demyelinating syndromes, there is a multitude of disorders, including optic neuritis, transverse myelitis, acute disseminated encephalomyelitis (ADEM), multiple sclerosis (MS), and neuromyelitis optica spectrum disorders (NMOSD). Due to overlapping clinical and magnetic resonance imaging (MRI) features, it can be challenging to provide an accurate diagnosis. In view of therapeutic and prognostic implications, an early and reliable diagnosis is however of utmost importance. Recent studies of myelin oligodendrocyte glycoprotein (MOG) identify MOG, as a promising target for antibody-mediated demyelination and a biomarker for a relatively benign and non-MS disease course. We describe the clinical and MRI presentation of five children presenting with an acute, severe central nervous system inflammatory disease involving the brain and spinal cord, all of whom were positive for MOG-IgG antibody. Encephalopathy was uncommon at presentation and all had quick resolution of symptoms with intravenous steroid and intravenous immunoglobulin (IVIG) treatment. All patients recovered well, and have been treated with IVIG to potentially prevent relapses. PMID:27128728

  14. Myelin proteolipid protein (PLP) as a marker antigen of central nervous system contaminations for routine food control.

    PubMed

    Villmann, Carmen; Sandmeier, Barbara; Seeber, Silke; Hannappel, Ewald; Pischetsrieder, Monika; Becker, Cord-Michael

    2007-08-22

    Spreading transmissible spongiform encephalopathies (TSE) have been widely attributed to transmission by ingestion of mammalian central nervous system (CNS) tissue. Reliable exclusion of this epidemiological important route of transmission relies on an effective surveillance of food contamination. Here, myelin proteolipid protein (PLP) is identified as a specific and largely heat-resistant marker for detection of food contaminations by CNS tissue. PLP is a component of oligodendritic glial sheaths of neuronal processes that is specifically expressed in the CNS. A highly selective polyclonal antibody was developed directed against an epitope present in the full-length PLP protein, but absent from the developmentally regulated splice variant DM-20. In combination with a hydrophobic extraction of PLP from tissue samples, the antibody reliably detected PLP from spinal cord, cerebellum, and cortex of different mammalian species. Consistent with earlier reports on PLP expression, no cross-reactivity was observed with peripheral nerve or extraneural tissue, except for a very faint signal obtained with heart. When applied to an artificial CNS contamination present in sausages, the antibody reliably detected a low concentration (1%) of the contaminant. Application of heat, as used during conventional sausage manufacturing, led to a predominant alteration of arginine residues in the PLP protein and a partial loss of immunoreactivity. In contrast, a stretch of hydrophilic amino acids(112-122) proved to be heat-resistant, preserving the immunogenicity of this PLP epitope during heating. Taken together, the excellent CNS specificity of PLP immunodetection and the presence of a heat-resistant epitope have permitted the development of a highly sensitive immunoassay for CNS contamination in routine food control. PMID:17629299

  15. Transplantation of mesenchymal stem cells promotes the functional recovery of the central nervous system following cerebral ischemia by inhibiting myelin-associated inhibitor expression and neural apoptosis

    PubMed Central

    FENG, NIANPING; HAO, GUANG; YANG, FENGGANG; QU, FUJUN; ZHENG, HAIHONG; LIANG, SONGLAN; JIN, YONGHUA

    2016-01-01

    Cerebral ischemia, which may lead to cerebral hypoxia and damage of the brain tissue, is a leading cause of human mortality and adult disability. Mesenchymal stem cells (MSCs) are a class of adult progenitor cells with the ability to differentiate into multiple cell types. The transplantation of bone marrow-derived MSCs is a potential therapeutic strategy for cerebral ischemia. However, the underlying mechanism has yet to be elucidated. In the present study, primary MSCs were isolated from healthy rats, labeled and transplanted into the brains of middle cerebral artery occlusion rat models. The location of the labeled MSCs in the rat brains were determined by fluorescent microscopy, and the neurological functions of the rats were scored. Immunohistochemical analyses demonstrated that the protein expression levels of myelin-associated inhibitors of regeneration, including Nogo-A, oligodendrocyte myelin glycoprotein and myelin-associated glycoprotein, were decreased following transplantation of the bone marrow-derived MSCs. Furthermore, the mRNA expression levels of Capase-3 and B-cell lymphoma 2, as determined by reverse transcription-quantitative polymerase chain reactions, were downregulated and upregulated, respectively, in the MSC-transplanted rats; thus suggesting that neural apoptosis was inhibited. The results of the present study suggested that the transplantation of bone marrow-derived MSCs was able to promote the functional recovery of the central nervous system following cerebral ischemia. Accordingly, inhibitors targeting myelin-associated inhibitors and apoptosis may be of clinical significance for cerebral ischemia in the future. PMID:27168778

  16. Role of IL-33 and ST2 signalling pathway in multiple sclerosis: expression by oligodendrocytes and inhibition of myelination in central nervous system.

    PubMed

    Allan, Debbie; Fairlie-Clarke, Karen J; Elliott, Christina; Schuh, Cornelia; Barnett, Susan C; Lassmann, Hans; Linnington, Christopher; Jiang, Hui-Rong

    2016-01-01

    Recent research findings have provided convincing evidence indicating a role for Interleukin-33 (IL-33) signalling pathway in a number of central nervous system (CNS) diseases including multiple sclerosis (MS) and Alzheimer's disease. However, the exact function of IL-33 molecule within the CNS under normal and pathological conditions is currently unknown. In this study, we have mapped cellular expression of IL-33 and its receptor ST2 by immunohistochemistry in the brain tissues of MS patients and appropriate controls; and investigated the functional significance of these findings in vitro using a myelinating culture system. Our results demonstrate that IL-33 is expressed by neurons, astrocytes and microglia as well as oligodendrocytes, while ST2 is expressed in the lesions by oligodendrocytes and within and around axons. Furthermore, the expression levels and patterns of IL-33 and ST2 in the lesions of acute and chronic MS patient brain samples are enhanced compared with the healthy brain tissues. Finally, our data using rat myelinating co-cultures suggest that IL-33 may play an important role in MS development by inhibiting CNS myelination. PMID:27455844

  17. 2',3'-cyclic nucleotide 3'-phosphodiesterase, an oligodendrocyte-Schwann cell and myelin-associated enzyme of the nervous system.

    PubMed

    Sprinkle, T J

    1989-01-01

    2',3'-Cyclic nucleotide 3'-phosphohydrolase (E.C. 3.1.4.37; CNPase) is a myelin-associated enzyme. In central and peripheral nervous system tissues, the enzyme is localized almost exclusively in the two cell types that elaborate myelin, the oligodendrocyte and the Schwann cell, respectively. Nonneural sources of CNPase have also been described, but they all have much lower activities than those found in brain. The freshly isolated brain enzymes appear as closely spaced doublets at approximately 46 and 48 kDa on SDS-PAGE. The primary sequence appears highly conserved between these two proteins, designated CNP1 and CNP2. Major structural differences between these two proteins are most likely due to posttranslational modifications of the enzyme itself (certainly phosphorylation, possibly others) or to alternative splicing. The primary sequences of rat and bovine brain CNPase have now been deduced from the cDNA sequences and the enzymes appear to be unique. Current research suggests that CNPase is involved in the very rapid growth of myelin membrane during early oligodendrocyte membrane biogenesis and possibly maintenance. The absolute hydrolysis specificity, yielding 2'-mononucleotides from 2',3'-cyclic substrates, strongly suggests that CNPase is a nucleic acid enzyme, possibly related to RNA metabolism. PMID:2537684

  18. Reduced BACE1 activity enhances clearance of myelin debris and regeneration of axons in the injured peripheral nervous system

    PubMed Central

    Farah, Mohamed H.; Pan, Bao Han; Hoffman, Paul N.; Ferraris, Dana; Tsukamoto, Takashi; Nguyen, Thien; Wong, Philip C.; Price, Donald L.; Slusher, Barbara S.; Griffin, John W.

    2012-01-01

    β- site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is an aspartyl protease best known for its role in generating the amyloid β peptides that are present in plaques of Alzheimer's Disease. BACE1 has been an attractive target for drug development. In cultured embryonic neurons BACE1-cleaved N-terminal APP is further processed to generate a fragment that can trigger axonal degeneration, suggesting a vital role for BACE1 in axonal health. In addition, BACE1 cleaves neuregulin 1 type III, a protein critical for myelination of peripheral axons by Schwann cells during development. Here, we asked if axonal degeneration or axonal regeneration in adult nerves might be affected by inhibition or elimination of BACE1. We report that BACE1 knockout and wild-type nerves degenerated at a similar rate after axotomy and to a similar extent in the experimental neuropathies produced by administration of paclitaxel and acrylamide. These data indicate N-APP is not the sole culprit in axonal degeneration in adult nerves. Unexpectedly, however, we observed that BACE1 knockout mice had markedly enhanced clearance of axonal and myelin debris from degenerated fibers, accelerated axonal regeneration, and earlier reinnervation of neuromuscular junctions, compared to littermate controls. These observations were reproduced in part by pharmacological inhibition of BACE1. These data suggest BACE1 inhibition as a therapeutic approach to accelerate regeneration and recovery after peripheral nerve damage. PMID:21490216

  19. Essential role of B-Raf in oligodendrocyte maturation and myelination during postnatal central nervous system development

    PubMed Central

    Galabova-Kovacs, Gergana; Catalanotti, Federica; Matzen, Dana; Reyes, Gloria X.; Zezula, Jürgen; Herbst, Ruth; Silva, Alcino; Walter, Ingrid; Baccarini, Manuela

    2008-01-01

    Mutations in the extracellular signal-regulated kinase (ERK) pathway, particularly in the mitogen-activated protein kinase/ERK kinase (MEK) activator B-Raf, are associated with human tumorigenesis and genetic disorders. Hence, B-Raf is a prime target for molecule-based therapies, and understanding its essential biological functions is crucial for their success. B-Raf is expressed preferentially in cells of neuronal origin. Here, we show that in mice, conditional ablation of B-Raf in neuronal precursors leads to severe dysmyelination, defective oligodendrocyte differentiation, and reduced ERK activation in brain. Both B-Raf ablation and chemical inhibition of MEK impair oligodendrocyte differentiation in vitro. In glial cell cultures, we find B-Raf in a complex with MEK, Raf-1, and kinase suppressor of Ras. In B-Raf–deficient cells, more Raf-1 is recruited to MEK, yet MEK/ERK phosphorylation is impaired. These data define B-Raf as the rate-limiting MEK/ERK activator in oligodendrocyte differentiation and myelination and have implications for the design and use of Raf inhibitors. PMID:18332218

  20. The human myelin basic protein gene is included within a 179-kilobase transcription unit: Expression in the immune and central nervous systems

    SciTech Connect

    Pribyl, T.M.; Campagnoni, C.W.; Kampf, K.; Kashima, T.; Handley, V.W.; Campagnoni, A.T. ); McMahon, J. )

    1993-11-15

    Two human Golli (for gene expressed in the oligodendrocyte lineage)-MBP (for myelin basic protein) cDNAs have been isolated from a human oligodendroglioma cell line. Analysis of these cDNAs has enabled the authors to determine the entire structure of the human Golli-MBP gene. The Golli-MBP gene, which encompasses the MBP transcription unit, is [approx] 179 kb in length and consists of 10 exons, seven of which constitute the MBP gene. The human Golli-MBP gene contains two transcription start sites, each of which gives rise to a family of alternatively spliced transcipts. At least two Golli-MBP transcripts, containing the first three exons of the gene and one or more MBP exons, are produced from the first transcription start site. The second family of transcripts contains only MBP exons and produces the well-known MBPs. In humans, RNA blot analysis revealed that Golli-MBP transcripts were expressed in fetal thymus, spleen, and human B-cell and macrophage cell lines, as well as in fetal spinal cord. These findings clearly link the expression of exons encoding the autoimmunogen/encephalitogen MBP in the central nervous system to cells and tissues of the immune system through normal expression of the Golli-MBP gene. They also establish that this genetic locus, which includes the MBP gene, is conserved among species, providing further evidence that the MBP transcription unit is an integral part of the Golli transcription unit and suggest that this structural arrangement is important for the genetic function and/or regulation of these genes.

  1. Autonomic Nervous System Disorders

    MedlinePlus

    Your autonomic nervous system is the part of your nervous system that controls involuntary actions, such as the beating ... with breathing and swallowing Erectile dysfunction in men Autonomic nervous system disorders can occur alone or as ...

  2. Autonomic Nervous System Disorders

    MedlinePlus

    Your autonomic nervous system is the part of your nervous system that controls involuntary actions, such as the beating of your heart ... breathing and swallowing Erectile dysfunction in men Autonomic nervous system disorders can occur alone or as the result ...

  3. Transfer of myelin-reactive th17 cells impairs endogenous remyelination in the central nervous system of cuprizone-fed mice.

    PubMed

    Baxi, Emily G; DeBruin, Joseph; Tosi, Dominique M; Grishkan, Inna V; Smith, Matthew D; Kirby, Leslie A; Strasburger, Hayley J; Fairchild, Amanda N; Calabresi, Peter A; Gocke, Anne R

    2015-06-01

    Multiple sclerosis (MS) is a demyelinating disease of the CNS characterized by inflammation and neurodegeneration. Animal models that enable the study of remyelination in the context of ongoing inflammation are greatly needed for the development of novel therapies that target the pathological inhibitory cues inherent to the MS plaque microenvironment. We report the development of an innovative animal model combining cuprizone-mediated demyelination with transfer of myelin-reactive CD4(+) T cells. Characterization of this model reveals both Th1 and Th17 CD4(+) T cells infiltrate the CNS of cuprizone-fed mice, with infiltration of Th17 cells being more efficient. Infiltration correlates with impaired spontaneous remyelination as evidenced by myelin protein expression, immunostaining, and ultrastructural analysis. Electron microscopic analysis further reveals that demyelinated axons are preserved but reduced in caliber. Examination of the immune response contributing to impaired remyelination highlights a role for peripheral monocytes with an M1 phenotype. This study demonstrates the development of a novel animal model that recapitulates elements of the microenvironment of the MS plaque and reveals an important role for T cells and peripheral monocytes in impairing endogenous remyelination in vivo. This model could be useful for testing putative MS therapies designed to enhance remyelination in the setting of active inflammation, and may also facilitate modeling the pathophysiology of denuded axons, which has been a challenge in rodents because they typically remyelinate very quickly. PMID:26041928

  4. Central nervous system

    MedlinePlus

    The central nervous system is composed of the brain and spinal cord. Your brain and spinal cord serve as the main "processing center" for your entire nervous system. They control all the workings of your body.

  5. Nerve Regeneration in the Peripheral Nervous System versus the Central Nervous System and the Relevance to Speech and Hearing after Nerve Injuries

    ERIC Educational Resources Information Center

    Gordon, Tessa; Gordon, Karen

    2010-01-01

    Schwann cells normally form myelin sheaths around axons in the peripheral nervous system (PNS) and support nerve regeneration after nerve injury. In contrast, nerve regeneration in the central nervous system (CNS) is not supported by the myelinating cells known as oligodendrocytes. We have found that: 1) low frequency electrical stimulation can be…

  6. Remyelination of the central nervous system: a valuable contribution from the periphery.

    PubMed

    Zujovic, Violetta; Bachelin, Corinne; Baron-Van Evercooren, Anne

    2007-08-01

    The loss of myelin, a major element involved in the saltatory conduction of the electrical impulse of the nervous system, is a major target of current research. Serious long-term disabilities are observed in patients with demyelinating disease of the central nervous system, such as multiple sclerosis. New therapeutic strategies aimed at overcoming myelin damage and axonal loss focus on the repair potential of myelin-forming cells. This review examines the use of peripheral myelin-forming cells, the Schwann cells, to promote myelin repair. PMID:17644768

  7. Normal adult ramified microglia separated from other central nervous system macrophages by flow cytometric sorting: Phenotypic differences defined and direct ex vivo antigen presentation to myelin basic protein-reactive CD4{sup +} T cells compared

    SciTech Connect

    Ford, A.L.; Goodsall, A.L.; Sedgwick, J.D.

    1995-05-01

    Ramified microglia in the adult central nervous system (CNS) are the principal glial element up-regulating MHC class I and II expression in response to inflammatory events or neuronal damage. A proportion of these cells also express MHC class II constitutively in the normal CNS. The role of microglia as APCs for CD4{sup +} cells extravasating into the CNS remains undefined. In this study, using irradiation bone marrow chimeras in CD45-congenic rats, the phenotype CD45{sup low}CD11b/c{sup +} is shown to identify microglial cells specifically within the CNS. Highly purified populations of microglia and nonmicroglial but CNS-associated macrophages (CD45{sup high}CD11b/c{sup +}) have been obtained directly from the adult CNS, by using flow cytometric sorting. Morphologically, freshly isolated microglia vs other CNS macrophages are quite distinct. Of the two populations recovered from the normal CNS, it is the minority CD45{sup high}CD11 b/c{sup +} transitional macrophage population, and not microglia, that is the effective APC for experimental autoimmune encephalomyelitis-inducing CD4{sup +} myelin basic protein (MBP)-reactive T cells. CD45{sup high}CD11b/c{sup +} CNS macrophages also stimulate MBP-reactive T cells without addition of MBP to culture suggesting presentation of endogenous Ag. This is the first study in which microglia vs other CNS macrophages have been analyzed for APC ability directly from the CNS, with substantial cross-contamination between the two populations eliminated. The heterogeneity of these populations in terms of APC function is clearly demonstrated. Evidence is still lacking that adult CNS microglia have the capacity to interact with and stimulate CD4{sup +} T cells to proliferate or secrete IL-2. 60 refs., 6 figs., 1 tab.

  8. Subcortical cytoskeleton periodicity throughout the nervous system.

    PubMed

    D'Este, Elisa; Kamin, Dirk; Velte, Caroline; Göttfert, Fabian; Simons, Mikael; Hell, Stefan W

    2016-01-01

    Superresolution fluorescence microscopy recently revealed a ~190 nm periodic cytoskeleton lattice consisting of actin, spectrin, and other proteins underneath the membrane of cultured hippocampal neurons. Whether the periodic cytoskeleton lattice is a structural feature of all neurons and how it is modified when axons are ensheathed by myelin forming glial cells is not known. Here, STED nanoscopy is used to demonstrate that this structure is a commonplace of virtually all neuron types in vitro. To check how the subcortical meshwork is modified during myelination, we studied sciatic nerve fibers from adult mice. Periodicity of both actin and spectrin was uncovered at the internodes, indicating no substantial differences between unmyelinated and myelinated axons. Remarkably, the actin/spectrin pattern was also detected in glial cells such as cultured oligodendrocyte precursor cells. Altogether our work shows that the periodic subcortical cytoskeletal meshwork is a fundamental characteristic of cells in the nervous system and is not a distinctive feature of neurons, as previously thought. PMID:26947559

  9. Nervous System Lyme Disease.

    PubMed

    Halperin, John J

    2015-12-01

    Nervous system involvement occurs in 10% to 15% of patients infected with the tick-borne spirochetes Borrelia burgdorferi, B afzelii, and B garinii. Peripheral nervous system involvement is common. Central nervous system (CNS) involvement, most commonly presenting with lymphocytic meningitis, causes modest cerebrospinal fluid (CSF) pleocytosis. Parenchymal CNS infection is rare. If the CNS is invaded, however, measuring local production of anti-B burgdorferi antibodies in the CSF provides a useful marker of infection. Most cases of neuroborreliosis can be cured with oral doxycycline; parenteral regimens should be reserved for patients with particularly severe disease. PMID:26593257

  10. MYELIN BASIC PROTEIN-MESSENGER RNA (MBP-MRNA) EXPRESSION DURING TRIETHYLTIN-INDUCED MYELIN EDEMA

    EPA Science Inventory

    Triethyltin (TET) is a neurotoxicant that produces severe but transient cerebral edema, characterized ultrastructurally by vacuolation of the intraperiod line of central nervous system (CNS) myelin. ET has been reported to depress levels of myelin basic protein (MBP), a glycoprot...

  11. The Nervous System Game

    ERIC Educational Resources Information Center

    Corbitt, Cynthia; Carpenter, Molly

    2006-01-01

    For many children, especially those with reading difficulties, a motor-kinesthetic learning activity may be an effective tool to teach complex concepts. With this in mind, the authors developed and tested a game designed to teach fourth- to sixth-grade children some basic principles of nervous system function by allowing the children themselves to…

  12. LGI proteins in the nervous system.

    PubMed

    Kegel, Linde; Aunin, Eerik; Meijer, Dies; Bermingham, John R

    2013-01-01

    The development and function of the vertebrate nervous system depend on specific interactions between different cell types. Two examples of such interactions are synaptic transmission and myelination. LGI1-4 (leucine-rich glioma inactivated proteins) play important roles in these processes. They are secreted proteins consisting of an LRR (leucine-rich repeat) domain and a so-called epilepsy-associated or EPTP (epitempin) domain. Both domains are thought to function in protein-protein interactions. The first LGI gene to be identified, LGI1, was found at a chromosomal translocation breakpoint in a glioma cell line. It was subsequently found mutated in ADLTE (autosomal dominant lateral temporal (lobe) epilepsy) also referred to as ADPEAF (autosomal dominant partial epilepsy with auditory features). LGI1 protein appears to act at synapses and antibodies against LGI1 may cause the autoimmune disorder limbic encephalitis. A similar function in synaptic remodelling has been suggested for LGI2, which is mutated in canine Benign Familial Juvenile Epilepsy. LGI4 is required for proliferation of glia in the peripheral nervous system and binds to a neuronal receptor, ADAM22, to foster ensheathment and myelination of axons by Schwann cells. Thus, LGI proteins play crucial roles in nervous system development and function and their study is highly important, both to understand their biological functions and for their therapeutic potential. Here, we review our current knowledge about this important family of proteins, and the progress made towards understanding their functions. PMID:23713523

  13. LGI proteins in the nervous system

    PubMed Central

    Kegel, Linde; Aunin, Eerik; Meijer, Dies; Bermingham, John R.

    2013-01-01

    The development and function of the vertebrate nervous system depend on specific interactions between different cell types. Two examples of such interactions are synaptic transmission and myelination. LGI1-4 (leucine-rich glioma inactivated proteins) play important roles in these processes. They are secreted proteins consisting of an LRR (leucine-rich repeat) domain and a so-called epilepsy-associated or EPTP (epitempin) domain. Both domains are thought to function in protein–protein interactions. The first LGI gene to be identified, LGI1, was found at a chromosomal translocation breakpoint in a glioma cell line. It was subsequently found mutated in ADLTE (autosomal dominant lateral temporal (lobe) epilepsy) also referred to as ADPEAF (autosomal dominant partial epilepsy with auditory features). LGI1 protein appears to act at synapses and antibodies against LGI1 may cause the autoimmune disorder limbic encephalitis. A similar function in synaptic remodelling has been suggested for LGI2, which is mutated in canine Benign Familial Juvenile Epilepsy. LGI4 is required for proliferation of glia in the peripheral nervous system and binds to a neuronal receptor, ADAM22, to foster ensheathment and myelination of axons by Schwann cells. Thus, LGI proteins play crucial roles in nervous system development and function and their study is highly important, both to understand their biological functions and for their therapeutic potential. Here, we review our current knowledge about this important family of proteins, and the progress made towards understanding their functions. PMID:23713523

  14. Microglia: Architects of the Developing Nervous System.

    PubMed

    Frost, Jeffrey L; Schafer, Dorothy P

    2016-08-01

    Microglia are resident macrophages of the central nervous system (CNS), representing 5-10% of total CNS cells. Recent findings reveal that microglia enter the embryonic brain, take up residence before the differentiation of other CNS cell types, and become critical regulators of CNS development. Here, we discuss exciting new work implicating microglia in a range of developmental processes, including regulation of cell number and spatial patterning of CNS cells, myelination, and formation and refinement of neural circuits. Furthermore, we review studies suggesting that these cellular functions result in the modulation of behavior, which has important implications for a variety of neurological disorders. PMID:27004698

  15. Subcortical cytoskeleton periodicity throughout the nervous system

    PubMed Central

    D’Este, Elisa; Kamin, Dirk; Velte, Caroline; Göttfert, Fabian; Simons, Mikael; Hell, Stefan W.

    2016-01-01

    Superresolution fluorescence microscopy recently revealed a ~190 nm periodic cytoskeleton lattice consisting of actin, spectrin, and other proteins underneath the membrane of cultured hippocampal neurons. Whether the periodic cytoskeleton lattice is a structural feature of all neurons and how it is modified when axons are ensheathed by myelin forming glial cells is not known. Here, STED nanoscopy is used to demonstrate that this structure is a commonplace of virtually all neuron types in vitro. To check how the subcortical meshwork is modified during myelination, we studied sciatic nerve fibers from adult mice. Periodicity of both actin and spectrin was uncovered at the internodes, indicating no substantial differences between unmyelinated and myelinated axons. Remarkably, the actin/spectrin pattern was also detected in glial cells such as cultured oligodendrocyte precursor cells. Altogether our work shows that the periodic subcortical cytoskeletal meshwork is a fundamental characteristic of cells in the nervous system and is not a distinctive feature of neurons, as previously thought. PMID:26947559

  16. Role of the Thyroid System in Myelination and Neural Connectivity.

    PubMed

    Calzà, Laura; Fernández, Mercedes; Giardino, Luciana

    2015-07-01

    The role of thyroid hormone on brain development is dramatically illustrated by "cretinism," a severe mental retardation due to iodine deficiency and maternal hypothyroidism during gestation. In the last decades, the molecular bases of the cellular action of thyroid hormone in the nervous tissue have been at least partially elucidated, and the emerged picture is much more complex than expected. In this article, the main mechanisms determining thyroid hormone availability, nuclear and membrane receptor occupancy and downstream action, gene expression, and nongenomic mechanism are reviewed, focusing on myelination and myelin turnover. PMID:26140723

  17. Connexin32 expression in central and peripheral nervous systems

    SciTech Connect

    Deschenes, S.M.; Scherer, S.S.; Fischbeck, K.H.

    1994-09-01

    Mutations have been identified in the gap junction gene, connexin32 (Cx32), in patients affected with the X-linked form of the demyelinating neuropathy, Charcot-Marie-Tooth disease (CMTX). Gap junctions composed of Cx32 are present and developmentally regulated in a wide variety of tissues. In peripheral nerve, our immunohistochemical analysis localized Cx32 to the noncompacted myelin of the paranodal regions and the Schmidt-Lantermann incisures, where previous studies describe gap junctions. In contrast to the location of Cx32 in peripheral nerve and the usual restriction of clinical manifestations to the peripheral nervous system (PNS) (abstract by Paulson describes an exception), preliminary studies show that Cx32 is present in the compacted myelin of the central nervous system (CNS), as demonstrated by radial staining through the myelin sheath of oligodendrocytes in rat spinal cord. Analysis of Cx32 expression in various regions of rat CNS during development shows that the amount of Cx32 mRNA and protein increases as myelination increases, a pattern observed for other myelin genes. Studies in the PNS provide additional evidence that Cx32 and myelin genes are coordinately regulated at the transcriptional level; Cx32 and peripheral myelin gene PMP-22 mRNAs are expressed in parallel following transient or permanent nerve injury. Differences in post-translational regulation of Cx32 in the CNS and PNS may be indicated by the presence of a faster migrating form of Cs32 in cerebrum versus peripheral nerve. Studies are currently underway to determine the unique role of Cx32 in peripheral nerve.

  18. Localization and characterization of gelsolin in nervous tissues: gelsolin is specifically enriched in myelin-forming cells.

    PubMed

    Tanaka, J; Sobue, K

    1994-03-01

    Gelsolin is a Ca(2+)-sensitive actin filament-severing protein. To elucidate the role of gelsolin in nervous tissues, we have investigated localization and expression of gelsolin in rat CNS and PNS using biochemical and morphological methods with a polyclonal antibody against the COOH-terminal fragment of plasma gelsolin. Immunohistochemical study showed that gelsolin was specifically enriched in oligodendrocytes and Schwann cells, and was also detected in myelin sheath, especially around the Ranvier's nodes. The immunohistochemical stainings using indirect immunofluorescence, avidin-biotin-peroxidase complex, and immunogold methods were carefully confirmed by immunoblotting against the tissue homogenates. The expressional changes of gelsolin in developing brain were investigated. The protein was detectable in newborn rat brain; however, it began to increase at 8-10 d after birth and reached maximal at 20-30 d when myelinogenesis actively occurred. After this period, the protein decreased gradually, although myelin basic protein was increasing until 6 months after birth. The immunostaining of gelsolin in Schwann cells was enhanced upon regeneration of injured sciatic nerves by freezing. Immunoelectron microscopy revealed that gelsolin was present not only in the cytoplasm but also in compact myelin. Following solubilization by detergents, gelsolin in the myelin fraction could be purified using anion exchange and blue Sepharose column chromatographies. The purified protein possessed a Ca(2+)-dependent severing activity against actin filaments similar to that of cytoplasmic and plasma gelsolin. These data strongly suggest that gelsolin in nervous tissues might be involved in lamellipodial movement to wrap axons of myelin-forming cells by modulating actin polymerization. PMID:8120612

  19. Central Nervous System Lipoproteins

    PubMed Central

    Mahley, Robert W.

    2016-01-01

    ApoE on high-density lipoproteins is primarily responsible for lipid transport and cholesterol homeostasis in the central nervous system (CNS). Normally produced mostly by astrocytes, apoE is also produced under neuropathologic conditions by neurons. ApoE on high-density lipoproteins is critical in redistributing cholesterol and phospholipids for membrane repair and remodeling. The 3 main structural isoforms differ in their effectiveness. Unlike apoE2 and apoE3, apoE4 has markedly altered CNS metabolism, is associated with Alzheimer disease and other neurodegenerative disorders, and is expressed at lower levels in brain and cerebrospinal fluid. ApoE4-expressing cultured astrocytes and neurons have reduced cholesterol and phospholipid secretion, decreased lipid-binding capacity, and increased intracellular degradation. Two structural features are responsible for apoE4 dysfunction: domain interaction, in which arginine-61 interacts ionically with glutamic acid-255, and a less stable conformation than apoE3 and apoE2. Blocking domain interaction by gene targeting (replacing arginine-61 with threonine) or by small-molecule structure correctors increases CNS apoE4 levels and lipid-binding capacity and decreases intracellular degradation. Small molecules (drugs) that disrupt domain interaction, so-called structure correctors, could prevent the apoE4-associated neuropathology by blocking the formation of neurotoxic fragments. Understanding how to modulate CNS cholesterol transport and metabolism is providing important insights into CNS health and disease. PMID:27174096

  20. Nervous System Complexity Baffles Scientists.

    ERIC Educational Resources Information Center

    Fox, Jeffrey L.

    1982-01-01

    New research findings about how nerve cells transmit signals are forcing researchers to overhaul their simplistic ideas about the nervous system. Topics highlighted include the multiple role of peptides in the nervous system, receptor molecules, and molecules that form ion channels within membranes. (Author/JN)

  1. Adaptive myelination from fish to man.

    PubMed

    Baraban, Marion; Mensch, Sigrid; Lyons, David A

    2016-06-15

    Myelinated axons with nodes of Ranvier are an evolutionary elaboration common to essentially all jawed vertebrates. Myelin made by Schwann cells in our peripheral nervous system and oligodendrocytes in our central nervous system has been long known to facilitate rapid energy efficient nerve impulse propagation. However, it is now also clear, particularly in the central nervous system, that myelin is not a simple static insulator but that it is dynamically regulated throughout development and life. New myelin sheaths can be made by newly differentiating oligodendrocytes, and mature myelin sheaths can be stimulated to grow again in the adult. Furthermore, numerous studies in models from fish to man indicate that neuronal activity can affect distinct stages of oligodendrocyte development and the process of myelination itself. This begs questions as to how these effects of activity are mediated at a cellular and molecular level and whether activity-driven adaptive myelination is a feature common to all myelinated axons, or indeed all oligodendrocytes, or is specific to cells or circuits with particular functions. Here we review the recent literature on this topic, elaborate on the key outstanding questions in the field, and look forward to future studies that incorporate investigations in systems from fish to man that will provide further insight into this fundamental aspect of nervous system plasticity. This article is part of a Special Issue entitled SI: Myelin Evolution. PMID:26498877

  2. Brain and nervous system (image)

    MedlinePlus

    The nervous system controls the many complicated and interconnected functions of the body and mind. Motor, sensory cognitive and autonomic function are all coordinated and driven by the brain and nerves. As people age, ...

  3. Brain and nervous system (image)

    MedlinePlus

    The nervous system controls the many complicated and interconnected functions of the body and mind. Motor, sensory cognitive and autonomic function are all coordinated and driven by the brain and nerves. As people age, nerve ...

  4. In vitro myelin formation using embryonic stem cells

    PubMed Central

    Kerman, Bilal E.; Kim, Hyung Joon; Padmanabhan, Krishnan; Mei, Arianna; Georges, Shereen; Joens, Matthew S.; Fitzpatrick, James A. J.; Jappelli, Roberto; Chandross, Karen J.; August, Paul; Gage, Fred H.

    2015-01-01

    Myelination in the central nervous system is the process by which oligodendrocytes form myelin sheaths around the axons of neurons. Myelination enables neurons to transmit information more quickly and more efficiently and allows for more complex brain functions; yet, remarkably, the underlying mechanism by which myelination occurs is still not fully understood. A reliable in vitro assay is essential to dissect oligodendrocyte and myelin biology. Hence, we developed a protocol to generate myelinating oligodendrocytes from mouse embryonic stem cells and established a myelin formation assay with embryonic stem cell-derived neurons in microfluidic devices. Myelin formation was quantified using a custom semi-automated method that is suitable for larger scale analysis. Finally, early myelination was followed in real time over several days and the results have led us to propose a new model for myelin formation. PMID:26015546

  5. Loss of Myelin Basic Protein Function Triggers Myelin Breakdown in Models of Demyelinating Diseases.

    PubMed

    Weil, Marie-Theres; Möbius, Wiebke; Winkler, Anne; Ruhwedel, Torben; Wrzos, Claudia; Romanelli, Elisa; Bennett, Jeffrey L; Enz, Lukas; Goebels, Norbert; Nave, Klaus-Armin; Kerschensteiner, Martin; Schaeren-Wiemers, Nicole; Stadelmann, Christine; Simons, Mikael

    2016-07-12

    Breakdown of myelin sheaths is a pathological hallmark of several autoimmune diseases of the nervous system. We employed autoantibody-mediated animal models of demyelinating diseases, including a rat model of neuromyelitis optica (NMO), to target myelin and found that myelin lamellae are broken down into vesicular structures at the innermost region of the myelin sheath. We demonstrated that myelin basic proteins (MBP), which form a polymer in between the myelin membrane layers, are targeted in these models. Elevation of intracellular Ca(2+) levels resulted in MBP network disassembly and myelin vesiculation. We propose that the aberrant phase transition of MBP molecules from their cohesive to soluble and non-adhesive state is a mechanism triggering myelin breakdown in NMO and possibly in other demyelinating diseases. PMID:27346352

  6. Antigen-specific down-regulation of myelin basic protein-reactive T cells during spontaneous recovery from experimental autoimmune encephalomyelitis: further evidence of apoptotic deletion of autoreactive T cells in the central nervous system.

    PubMed

    Tabi, Z; McCombe, P A; Pender, M P

    1995-06-01

    Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats by the i.v. injection of 10(7) cloned V beta 8.2+ T cells specific for the 72-89 peptide of guinea pig myelin basic protein (MBP). Some animals were injected simultaneously with 10(7) cloned T cells specific for ovalbumin (OVA). Lymphocytes were isolated from the spinal cord and from the peripheral lymphoid organs of these rats and the frequencies of MBP-peptide-specific or OVA-specific proliferating cells were estimated by limiting dilution analysis at different times after cell transfer. The frequencies of cells specific for MBP72-89 or OVA in the spinal cord were highest 5 days after cell transfer (MBP72-89, 1 in 1149; OVA, 1 in 1116). On day 7, when the rats were recovering, the frequency of cells specific for MBP72-89 in the spinal cord fell dramatically to < 1 in 10(5), while that of OVA-specific cells decreased to a much lesser extent (1 in 7001). The frequencies of MBP72-89-specific cells in the peripheral lymphoid organs during and after recovery were also much lower than those of OVA-specific cells. A similar pattern of down-regulation of the MBP-peptide-specific, but not the OVA-specific, T cell response was observed in the spleen and mesenteric lymph nodes (MLN) of rats 38 days after the active induction of EAE by immunization with equal amounts of MBP and OVA in adjuvants. In the passively transferred model, cells isolated from the spinal cord and MLN on day 7 did not regain responsiveness to MBP72-89 after incubation with high levels of IL-2, indicating that the unresponsiveness was not due to T cell anergy. Thus this study demonstrates that there is a specific down-regulation of the MBP72-89-specific T cell response during spontaneous recovery from EAE.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7577805

  7. [Vesalius and the nervous system].

    PubMed

    Van Laere, J

    1993-01-01

    Before we comment the subject of this lecture, we attract the reader's attention towards two remarks. We first want to point out that, although Vesalius is rightly considered as "the father of anatomy", in physiological matters--such as e.g. the physiology of the nervous system--he remained a faithful follower of Galen. A second preliminary remark explains why the books Vesalius devoted to the nervous system, namely the fourth and seventh books, as well as a part of the third book, don't belong to the best parts of the Fabrica, when we compare them with his Osteology and his Myology. We should not forget that some technical discoveries such as keeping brain-tissue in alcohol in order to harden it and colouring methods of Weigert, Marchi and Nissl, that made a refined macro- and microscopic examination of the nervous system possible, were only invented in the 19th century. The fourth book considers the peripheral nervous system. According to Vesalius, there are seven pairs of brain-nerves. His first pair corresponds to our Nervous opticus; his second pair concerns our Nervi oculomotorius, trochlearis and abducens; this third pair embraces a great part of our Nervus trigeminus; his fourth pair corresponds to our Nervus maxillaris; his fifth pair includes our Nervi facialis and acusticus; his sixth pair includes our Nervi vagus and accessorius; his seventh pair our Nervi hypoglossus and pharyngeus. Vesalius counts thirty pairs of spinal nerves. His description of the Plexus brachialis and the Plexus ischiadicus is closely related to the modern views in these matters. However, his teleologic views about them are remarkable, e.g. about the course of the Nervi recurrentes. The seventh book covers the brain. He successively and truly describes the cerebral membranes, the Ventriculi, the Cerebrum; his description relies on a series of horizontal slices. He also describes the brain-stem and the Cerebellum. Vesalius, who had doubts about the existence of the Plexus

  8. Lipids in the nervous system: from biochemistry and molecular biology to patho-physiology.

    PubMed

    Cermenati, Gaia; Mitro, Nico; Audano, Matteo; Melcangi, Roberto C; Crestani, Maurizio; De Fabiani, Emma; Caruso, Donatella

    2015-01-01

    Lipids in the nervous system accomplish a great number of key functions, from synaptogenesis to impulse conduction, and more. Most of the lipids of the nervous system are localized in myelin sheaths. It has long been known that myelin structure and brain homeostasis rely on specific lipid-protein interactions and on specific cell-to-cell signaling. In more recent years, the growing advances in large-scale technologies and genetically modified animal models have provided valuable insights into the role of lipids in the nervous system. Key findings recently emerged in these areas are here summarized. In addition, we briefly discuss how this new knowledge can open novel approaches for the treatment of diseases associated with alteration of lipid metabolism/homeostasis in the nervous system. This article is part of a Special Issue entitled Linking transcription to physiology in lipidomics. PMID:25150974

  9. Intravital assessment of myelin molecular order with polarimetric multiphoton microscopy

    PubMed Central

    Turcotte, Raphaël; Rutledge, Danette J.; Bélanger, Erik; Dill, Dorothy; Macklin, Wendy B.; Côté, Daniel C.

    2016-01-01

    Myelin plays an essential role in the nervous system and its disruption in diseases such as multiple sclerosis may lead to neuronal death, thus causing irreversible functional impairments. Understanding myelin biology is therefore of fundamental and clinical importance, but no tools currently exist to describe the fine spatial organization of myelin sheaths in vivo. Here we demonstrate intravital quantification of the myelin molecular structure using a microscopy method based on polarization-resolved coherent Raman scattering. Developmental myelination was imaged noninvasively in live zebrafish. Longitudinal imaging of individual axons revealed changes in myelin organization beyond the diffraction limit. Applied to promyelination drug screening, the method uniquely enabled the identification of focal myelin regions with differential architectures. These observations indicate that the study of myelin biology and the identification of therapeutic compounds will largely benefit from a method to quantify the myelin molecular organization in vivo. PMID:27538357

  10. Intravital assessment of myelin molecular order with polarimetric multiphoton microscopy.

    PubMed

    Turcotte, Raphaël; Rutledge, Danette J; Bélanger, Erik; Dill, Dorothy; Macklin, Wendy B; Côté, Daniel C

    2016-01-01

    Myelin plays an essential role in the nervous system and its disruption in diseases such as multiple sclerosis may lead to neuronal death, thus causing irreversible functional impairments. Understanding myelin biology is therefore of fundamental and clinical importance, but no tools currently exist to describe the fine spatial organization of myelin sheaths in vivo. Here we demonstrate intravital quantification of the myelin molecular structure using a microscopy method based on polarization-resolved coherent Raman scattering. Developmental myelination was imaged noninvasively in live zebrafish. Longitudinal imaging of individual axons revealed changes in myelin organization beyond the diffraction limit. Applied to promyelination drug screening, the method uniquely enabled the identification of focal myelin regions with differential architectures. These observations indicate that the study of myelin biology and the identification of therapeutic compounds will largely benefit from a method to quantify the myelin molecular organization in vivo. PMID:27538357

  11. Paraneoplastic nervous system syndromes.

    PubMed

    Jaeckle, K A

    1996-05-01

    Recent progress in the understanding of the paraneoplastic neurologic syndromes has included further deliniation of the clinical syndromes and their treatment, attempts at standardization of the diagnostic nomenclature, investigations of pathogenetic mechanisms, and molecular characterization of the paraneoplastic antigens with implications as to their biologic relevance. Despite more than 30 years of investigation, the pathogenesis of these presumably autoimmune conditions remains unclear. Furthermore, no effective therapy has been identified for these conditions, with the possible exception of the opsoclonus-myoclonus ataxia and Lambert-Eaton myasthenic syndromes. Future investigations must focus on the disrupted genetic regulatory events involved in generation and propagation of the autoimmune response, antigen presentation and processing; target cell destruction, and consideration of alternative pathologic causes. Effective management strategies are most likely to develop from a better understanding of the disease pathogenesis, the development of animal model systems, and a creative look beyond the usual therapies employed in autoimmune conditions. PMID:8794147

  12. Novel central nervous system drug delivery systems.

    PubMed

    Stockwell, Jocelyn; Abdi, Nabiha; Lu, Xiaofan; Maheshwari, Oshin; Taghibiglou, Changiz

    2014-05-01

    For decades, biomedical and pharmaceutical researchers have worked to devise new and more effective therapeutics to treat diseases affecting the central nervous system. The blood-brain barrier effectively protects the brain, but poses a profound challenge to drug delivery across this barrier. Many traditional drugs cannot cross the blood-brain barrier in appreciable concentrations, with less than 1% of most drugs reaching the central nervous system, leading to a lack of available treatments for many central nervous system diseases, such as stroke, neurodegenerative disorders, and brain tumors. Due to the ineffective nature of most treatments for central nervous system disorders, the development of novel drug delivery systems is an area of great interest and active research. Multiple novel strategies show promise for effective central nervous system drug delivery, giving potential for more effective and safer therapies in the future. This review outlines several novel drug delivery techniques, including intranasal drug delivery, nanoparticles, drug modifications, convection-enhanced infusion, and ultrasound-mediated drug delivery. It also assesses possible clinical applications, limitations, and examples of current clinical and preclinical research for each of these drug delivery approaches. Improved central nervous system drug delivery is extremely important and will allow for improved treatment of central nervous system diseases, causing improved therapies for those who are affected by central nervous system diseases. PMID:24325540

  13. Human nervous system function emulator.

    PubMed

    Frenger, P

    2000-01-01

    This paper describes a modular, extensible, open-systems design for a multiprocessor network which emulates the major functions of the human nervous system. Interchangeable hardware/software components, a socketed software bus with plug-and-play capability and self diagnostics are included. The computer hardware is based on IEEE P996.1 bus cards. Its operating system utilizes IEEE 1275 standard software. Object oriented design techniques and programming are featured. A machine-independent high level script-based command language was created for this project. Neural anatomical structures which were emulated include the cortex, brainstem, cerebellum, spinal cord, autonomic and peripheral nervous systems. Motor, sensory, autoregulatory, and higher cognitive artificial intelligence, behavioral and emotional functions are provided. The author discusses how he has interfaced this emulator to machine vision, speech recognition/speech synthesis, an artificial neural network and a dexterous hand to form an android robotic platform. PMID:10834247

  14. Phylogenetic development of myelin glycosphingolipids.

    PubMed

    Kishimoto, Y

    1986-12-15

    Myelin is a highly specialized membrane, which enwraps axons and facilitates saltatory nerve conduction in vertebrates. Galactocerebroside and its sulfate ester, sulfatide, are highly localized in myelin. To understand the role played by these galactosphingolipids we investigated the changes of these myelin-specific compounds during the course of the evolution of myelin. We found that urodele nerve myelin lacks alpha-hydroxy fatty acid-containing galactosphingolipids. Our morphological and physiological studies of urodele nerves indicated that these hydroxy fatty acid-containing galactosphingolipids probably contribute to fast nerve conduction. Also it is suspected that they are involved in the regulation of the thickness of myelin in relation to the size of the axon. In another study, we discovered that glucocerebroside, which has glucose instead of galactose as its carbohydrate component, is abundantly present in the myelin-like sheath membrane of crustacean nerves. Subsequently, the phylogenetic study indicated that galactocerebrosides were limited to the nervous system of deuterostomes, while all protostome nerves contain glucocerebrosides. The role of glucocerebrosides in multilayered membranes and in the conduction velocity of the protostome nervous system is discussed. PMID:3549016

  15. Nonsynaptic junctions on myelinating glia promote preferential myelination of electrically active axons

    PubMed Central

    Wake, Hiroaki; Ortiz, Fernando C.; Woo, Dong Ho; Lee, Philip R.; Angulo, María Cecilia; Fields, R. Douglas

    2015-01-01

    The myelin sheath on vertebrate axons is critical for neural impulse transmission, but whether electrically active axons are preferentially myelinated by glial cells, and if so, whether axo-glial synapses are involved, are long-standing questions of significance to nervous system development, plasticity and disease. Here we show using an in vitro system that oligodendrocytes preferentially myelinate electrically active axons, but synapses from axons onto myelin-forming oligodendroglial cells are not required. Instead, vesicular release at nonsynaptic axo-glial junctions induces myelination. Axons releasing neurotransmitter from vesicles that accumulate in axon varicosities induces a local rise in cytoplasmic calcium in glial cell processes at these nonsynaptic functional junctions, and this signalling stimulates local translation of myelin basic protein to initiate myelination. PMID:26238238

  16. Infections of the nervous system

    PubMed Central

    Parikh, Vevek; Tucci, Veronica; Galwankar, Sagar

    2012-01-01

    Glycemic control is an important aspect of patient care in the surgical Infections of the nervous system are among the most difficult infections in terms of the morbidity and mortality posed to patients, and thereby require urgent and accurate diagnosis. Although viral meningitides are more common, it is the bacterial meningitides that have the potential to cause a rapidly deteriorating condition that the physician should be familiar with. Viral encephalitis frequently accompanies viral meningitis, and can produce focal neurologic findings and cognitive difficulties that can mimic other neurologic disorders. Brain abscesses also have the potential to mimic and present like other neurologic disorders, and cause more focal deficits. Finally, other infectious diseases of the central nervous system, such as prion disease and cavernous sinus thrombosis, are explored in this review. PMID:22837896

  17. Septins in the glial cells of the nervous system.

    PubMed

    Patzig, Julia; Dworschak, Michelle S; Martens, Ann-Kristin; Werner, Hauke B

    2014-02-01

    The capacity of cytoskeletal septins to mediate diverse cellular processes is related to their ability to assemble as distinct heterooligomers and higher order structures. However, in many cell types the functional relevance of septins is not well understood. This minireview provides a brief overview of our current knowledge about septins in the non-neuronal cells of the vertebrate nervous system, collectively termed 'glial cells', i.e., astrocytes, microglia, oligodendrocytes, and Schwann cells. The dysregulation of septins observed in various models of myelin pathology is discussed with respect to implications for hereditary neuralgic amyotrophy (HNA) caused by mutations of the human SEPT9-gene. PMID:24047595

  18. Clinical implications of thyroid hormones effects on nervous system development.

    PubMed

    Carreón-Rodríguez, Alfonso; Pérez-Martínez, Leonor

    2012-03-01

    Thyroid hormones have an important role throughout prenatal and postnatal nervous system development. They are involved in several processes such as neurogenesis, gliogenesis, myelination, synaptogenesis, etc., as shown in many cases of deficiency like congenital hypothyroidism or hypothyroxinemia. Those pathologies if untreated could lead to severe damages in cognitive, motor, neudoendocrine functions among other effects. Some could be reversed after adequate supplementation of thyroid hormones at birth, however there are other cellular processes highly sensitive to low levels of thyroid hormones and lasting a limited period of time during which if thyroid hormone action is lacking or deficient, the functional and structural damages would produce permanent defects. PMID:22523832

  19. Extracellular vesicles round off communication in the nervous system

    PubMed Central

    Budnik, Vivian; Ruiz-Cañada, Catalina; Wendler, Franz

    2016-01-01

    Functional neural competence and integrity require interactive exchanges among sensory and motor neurons, interneurons and glial cells. Recent studies have attributed some of the tasks needed for these exchanges to extracellular vesicles (such as exosomes and microvesicles), which are most prominently involved in shuttling reciprocal signals between myelinating glia and neurons, thus promoting neuronal survival, the immune response mediated by microglia, and synapse assembly and plasticity. Such vesicles have also been identified as important factors in the spread of neurodegenerative disorders and brain cancer. These extracellular vesicle functions add a previously unrecognized level of complexity to transcellular interactions within the nervous system. PMID:26891626

  20. Maturation of the Central Nervous System as Related to Communication and Cognitive Development.

    ERIC Educational Resources Information Center

    Hallett, Terry; Proctor, Adele

    1996-01-01

    Major events in the maturation of the central nervous system (CNS) are reviewed relative to milestones for communication, speech, language, and cognition. Early insults to the CNS and their neuropsychological consequences are discussed. The role of patterns of myelination and dendritic branching to evolving stages of language and cognition are…

  1. Diversity Matters: A Revised Guide to Myelination.

    PubMed

    Tomassy, Giulio Srubek; Dershowitz, Lori Bowe; Arlotta, Paola

    2016-02-01

    The evolutionary success of the vertebrate nervous system is largely due to a unique structural feature--the myelin sheath, a fatty envelope that surrounds the axons of neurons. By increasing the speed by which electrical signals travel along axons, myelin facilitates neuronal communication between distant regions of the nervous system. We review the cellular and molecular mechanisms that regulate the development of myelin as well as its homeostasis in adulthood. We discuss how finely tuned neuron-oligodendrocyte interactions are central to myelin formation during development and in the adult, and how these interactions can have profound implications for the plasticity of the adult brain. We also speculate how the functional diversity of both neurons and oligodendrocytes may impact on the myelination process in both health and disease. PMID:26442841

  2. Aging changes in the nervous system

    MedlinePlus

    ... ency/article/004023.htm Aging changes in the nervous system To use the sharing features on this page, please enable JavaScript. The brain and nervous system are your body's central control center. They control ...

  3. HIV Infection Seems to Affect Nervous System

    MedlinePlus

    ... fullstory_159344.html HIV Infection Seems to Affect Nervous System But symptoms tend to subside once antiretroviral drugs ... mild, it is clear that HIV affects the nervous system within days of infection," she said in a ...

  4. The history of myelin.

    PubMed

    Boullerne, Anne Isabelle

    2016-09-01

    Andreas Vesalius is attributed the discovery of white matter in the 16th century but van Leeuwenhoek is arguably the first to have observed myelinated fibers in 1717. A globular myelin theory followed, claiming all elements of the nervous system except for Fontana's primitive cylinder with outer sheath in 1781. Remak's axon revolution in 1836 relegated myelin to the unknown. Ehrenberg described nerve tubes with double borders in 1833, and Schwann with nuclei in 1839, but the medullary sheath acquired its name of myelin, coined by Virchow, only in 1854. Thanks to Schultze's osmium specific staining in 1865, myelin designates the structure known today. The origin of myelin though was baffling. Only after Ranvier discovered a periodic segmentation, which came to us as nodes of Ranvier, did he venture suggesting in 1872 that the nerve internode was a fatty cell secreting myelin in cytoplasm. Ranvier's hypothesis was met with high skepticism, because nobody could see the cytoplasm, and the term Schwann cell very slowly emerged into the vocabulary with von Lenhossék in 1895. When Cajal finally admitted the concept of Schwann cell internode in 1912, he still firmly believed myelin was secreted by the axon. Del Río-Hortega re-discovered oligodendrocytes in 1919 (after Robertson in 1899) and named them oligodendroglia in 1921, thereby antagonizing Cajal for discovering a second cell type in his invisible third element. Penfield had to come to del Río-Hortega's rescue in 1924 for oligodendrocytes to be accepted. They jointly hypothesized myelin could be made by oligodendrocytes, considered the central equivalent of Schwann cells. Meanwhile myelin birefringence properties observed by Klebs in 1865 then Schmidt in 1924 confirmed its high fatty content, ascertained by biochemistry by Thudichum in 1884. The 20th century saw X-ray diffraction developed by Schmitt, who discovered in 1935 the crystal-like organization of this most peculiar structure, and devised the g

  5. [The role of metalloprotease in pathogenesis of nervous system diseases].

    PubMed

    Mirowska, D; Członkowska, A

    2001-01-01

    Matrix Metalloproteases (MMPs) comprise a big family of proteolytic enzymes secreted into extracellular matrix and involved in remodelling of many tissues. The MMPs' activity is regulated on many levels. It is also determined by specific inhibitors known as tissue inhibitors of metalloproteases (TIMPs). Several studies revealed that MMPs have a role not only in physiological processes but also in pathophysiology of nervous system diseases, such as multiplex sclerosis, Guillan-Barré syndrome and strokes. Concerning demyelination MMPs are responsible for degradation of myelin components and facilitation of immune cells migration into inflammatory sites by degrading vascular basement membrane. We still investigate substances with positive clinical effect on the nervous system diseases due to MMPs inactivation. PMID:11464705

  6. The Nervous System and Gastrointestinal Function

    ERIC Educational Resources Information Center

    Altaf, Muhammad A.; Sood, Manu R.

    2008-01-01

    The enteric nervous system is an integrative brain with collection of neurons in the gastrointestinal tract which is capable of functioning independently of the central nervous system (CNS). The enteric nervous system modulates motility, secretions, microcirculation, immune and inflammatory responses of the gastrointestinal tract. Dysphagia,…

  7. α-Synuclein-induced myelination deficit defines a novel interventional target for multiple system atrophy.

    PubMed

    Ettle, Benjamin; Kerman, Bilal E; Valera, Elvira; Gillmann, Clarissa; Schlachetzki, Johannes C M; Reiprich, Simone; Büttner, Christian; Ekici, Arif B; Reis, André; Wegner, Michael; Bäuerle, Tobias; Riemenschneider, Markus J; Masliah, Eliezer; Gage, Fred H; Winkler, Jürgen

    2016-07-01

    Multiple system atrophy (MSA) is a rare atypical parkinsonian disorder characterized by a rapidly progressing clinical course and at present without any efficient therapy. Neuropathologically, myelin loss and neurodegeneration are associated with α-synuclein accumulation in oligodendrocytes, but underlying pathomechanisms are poorly understood. Here, we analyzed the impact of oligodendrocytic α-synuclein on the formation of myelin sheaths to define a potential interventional target for MSA. Post-mortem analyses of MSA patients and controls were performed to quantify myelin and oligodendrocyte numbers. As pre-clinical models, we used transgenic MSA mice, a myelinating stem cell-derived oligodendrocyte-neuron co-culture, and primary oligodendrocytes to determine functional consequences of oligodendrocytic α-synuclein overexpression on myelination. We detected myelin loss accompanied by preserved or even increased numbers of oligodendrocytes in post-mortem MSA brains or transgenic mouse forebrains, respectively, indicating an oligodendrocytic dysfunction in myelin formation. Corroborating this observation, overexpression of α-synuclein in primary and stem cell-derived oligodendrocytes severely impaired myelin formation, defining a novel α-synuclein-linked pathomechanism in MSA. We used the pro-myelinating activity of the muscarinic acetylcholine receptor antagonist benztropine to analyze the reversibility of the myelination deficit. Transcriptome profiling of primary pre-myelinating oligodendrocytes demonstrated that benztropine readjusts myelination-related processes such as cholesterol and membrane biogenesis, being compromised by oligodendrocytic α-synuclein. Additionally, benztropine restored the α-synuclein-induced myelination deficit of stem cell-derived oligodendrocytes. Strikingly, benztropine also ameliorated the myelin deficit in transgenic MSA mice, resulting in a prevention of neuronal cell loss. In conclusion, this study defines the

  8. Molecular targets to promote central nervous system regeneration.

    PubMed

    Ferraro, Gino B; Alabed, Yazan Z; Fournier, Alyson E

    2004-01-01

    Trauma in the adult mammalian central nervous system (CNS) results in devastating clinical consequences due to the failure of injured axons to spontaneously regenerate. This regenerative failure can be attributed to both a lack of positive cues and to the presence of inhibitory cues that actively prevent regeneration. Substantial progress has been made in elucidating the molecular identity of negative cues present at the CNS injury site following injury. In the past several years, multiple myelin-associated inhibitors including Nogo, Myelin-associated glycoprotein and Oligodendrocyte-myelin glycoprotein have been characterized. Furthermore a neuronal receptor complex and several intracellular substrates leading to outgrowth inhibition have been identified. Rapid progress has also been made in identifying the role of neurotrophins and other positive cues in promoting axonal regrowth. The most recent advances in our understanding of positive stimuli for axon regeneration come from transplantation studies at the CNS lesion site. A number of artificial substrates, tissues, and cells including fetal cells, neural stem cells, Schwann cells and olfactory-ensheathing cells have been tested in animal models of CNS injury. Based on our expanded knowledge of inhibitory influences and on the positive characteristics of various transplants, a number of interventions have been tested to promote recovery in models of CNS trauma. These advances represent the first steps in developing a viable therapy to promote axon regeneration following CNS trauma. PMID:16181067

  9. Glucocorticoids and nervous system plasticity

    PubMed Central

    Madalena, Kathryn M.; Lerch, Jessica K.

    2016-01-01

    Glucocorticoid and glucocorticoid receptor (GC/GR) interactions alter numerous aspects of neuronal function. These consequences (e.g., anti-inflammatory vs. pro-inflammatory) can vary depending on the duration of GC exposure or central nervous system (CNS) injury model. In this review we discuss how GC/GR interactions impact neuronal recovery after a central or peripheral nerve injury and discuss how GC exposure duration can produce divergent CNS neuronal growth responses. Finally we consider how new findings on gender specific immune cell responses after a nerve injury could intersect with GC/GR interactions to impact pain processing. PMID:26981074

  10. Infections of the nervous system.

    PubMed

    Pruitt, A A

    1998-05-01

    Epidemiologic trends causing infections of the nervous system remain a significant source of morbidity and mortality one half-century after the introduction of penicillin. This article outlines common causes of bacterial meningitis, aseptic meningitis syndrome, encephalitis, abscess, spinal cord syndromes, and cranial and peripheral nerve problems. Recommendations for diagnostic evaluation and both empiric and definitive antimicrobial therapy are offered; controversial management issues are also discussed. The protean manifestations of varicella-zoster virus and Lyme diseases are outlined. In addition, special considerations in the immunocompromised host, including organ transplant recipients, cancer patients, and HIV-positive persons are explained, and antimicrobial therapy is discussed. PMID:9537969

  11. Lavender and the Nervous System

    PubMed Central

    Koulivand, Peir Hossein; Khaleghi Ghadiri, Maryam; Gorji, Ali

    2013-01-01

    Lavender is traditionally alleged to have a variety of therapeutic and curative properties, ranging from inducing relaxation to treating parasitic infections, burns, insect bites, and spasm. There is growing evidence suggesting that lavender oil may be an effective medicament in treatment of several neurological disorders. Several animal and human investigations suggest anxiolytic, mood stabilizer, sedative, analgesic, and anticonvulsive and neuroprotective properties for lavender. These studies raised the possibility of revival of lavender therapeutic efficacy in neurological disorders. In this paper, a survey on current experimental and clinical state of knowledge about the effect of lavender on the nervous system is given. PMID:23573142

  12. CFTR-deficient pigs display peripheral nervous system defects at birth

    PubMed Central

    Reznikov, Leah R.; Dong, Qian; Chen, Jeng-Haur; Moninger, Thomas O.; Park, Jung Min; Zhang, Yuzhou; Hildebrand, Michael S.; Smith, Richard J. H.; Randak, Christoph O.; Stoltz, David A.; Welsh, Michael J.

    2013-01-01

    Peripheral nervous system abnormalities, including neuropathy, have been reported in people with cystic fibrosis. These abnormalities have largely been attributed to secondary manifestations of the disease. We tested the hypothesis that disruption of the cystic fibrosis transmembrane conductance regulator (CFTR) gene directly influences nervous system function by studying newborn CFTR−/− pigs. We discovered CFTR expression and activity in Schwann cells, and loss of CFTR caused ultrastructural myelin sheath abnormalities similar to those in known neuropathies. Consistent with neuropathic changes, we found increased transcripts for myelin protein zero, a gene that, when mutated, can cause axonal and/or demyelinating neuropathy. In addition, axon density was reduced and conduction velocities of the trigeminal and sciatic nerves were decreased. Moreover, in vivo auditory brainstem evoked potentials revealed delayed conduction of the vestibulocochlear nerve. Our data suggest that loss of CFTR directly alters Schwann cell function and that some nervous system defects in people with cystic fibrosis are likely primary. PMID:23382208

  13. CFTR-deficient pigs display peripheral nervous system defects at birth.

    PubMed

    Reznikov, Leah R; Dong, Qian; Chen, Jeng-Haur; Moninger, Thomas O; Park, Jung Min; Zhang, Yuzhou; Du, Jianyang; Hildebrand, Michael S; Smith, Richard J H; Randak, Christoph O; Stoltz, David A; Welsh, Michael J

    2013-02-19

    Peripheral nervous system abnormalities, including neuropathy, have been reported in people with cystic fibrosis. These abnormalities have largely been attributed to secondary manifestations of the disease. We tested the hypothesis that disruption of the cystic fibrosis transmembrane conductance regulator (CFTR) gene directly influences nervous system function by studying newborn CFTR(-/-) pigs. We discovered CFTR expression and activity in Schwann cells, and loss of CFTR caused ultrastructural myelin sheath abnormalities similar to those in known neuropathies. Consistent with neuropathic changes, we found increased transcripts for myelin protein zero, a gene that, when mutated, can cause axonal and/or demyelinating neuropathy. In addition, axon density was reduced and conduction velocities of the trigeminal and sciatic nerves were decreased. Moreover, in vivo auditory brainstem evoked potentials revealed delayed conduction of the vestibulocochlear nerve. Our data suggest that loss of CFTR directly alters Schwann cell function and that some nervous system defects in people with cystic fibrosis are likely primary. PMID:23382208

  14. Aquaporin Biology and Nervous System

    PubMed Central

    Barbara, Buffoli

    2010-01-01

    Our understanding of the movement of water through cell membranes has been greatly advanced by the discovery of a family of water-specific, membrane-channel proteins: the Aquaporins (AQPs). These proteins are present in organisms at all levels of life, and their unique permeability characteristics and distribution in numerous tissues indicate diverse roles in the regulation of water homeostasis. Phenotype analysis of AQP knock-out mice has confirmed the predicted role of AQPs in osmotically driven transepithelial fluid transport, as occurs in the urinary concentrating mechanism and glandular fluid secretion. Regarding their expression in nervous system, there are evidences suggesting that AQPs are differentially expressed in the peripheral versus central nervous system and that channel-mediated water transport mechanisms may be involved in cerebrospinal fluid formation, neuronal signal transduction and information processing. Moreover, a number of recent studies have revealed the importance of mammalian AQPs in both physiological and pathophysiological mechanisms and have suggested that pharmacological modulation of AQP expression and activity may provide new tools for the treatment of variety of human disorders in which water and small solute transport may be involved. For all the AQPs, new contributions to physiological functions are likely to be discovered with ongoing work in this rapidly expanding field of research. PMID:21119880

  15. [Primary central nervous system vasculitis].

    PubMed

    Schuster, S; Magnus, T

    2015-12-01

    Primary angiitis of the central nervous system (PACNS) is a rare disorder. However, it is often considered in the differential diagnosis of vascular or inflammatory CNS diseases. Diagnosis is challenging, as specific biomarkers are lacking and the clinical presentation can be variable. A definitive diagnosis can only be established by biopsy of the inflammatory changes in the vascular wall. Alternatively, the diagnosis of PACNS can also be based on the synopsis of clinical, radiological, and laboratory findings. Different subtypes of PACNS have been described in recent years, depending on the size of the affected vessels or histopathological patterns. Based on selective literature research in the database PubMed on the subject of CNS vasculitis, this article reviews the diagnostic characteristics and differential diagnosis of the condition. We suggest a diagnostic algorithm customized to the size of the affected vessels. Lastly, therapeutic options and the outcome of PACNS are briefly outlined. PMID:26589203

  16. Binding of epsilon-toxin from Clostridium perfringens in the nervous system.

    PubMed

    Dorca-Arévalo, Jonatan; Soler-Jover, Alex; Gibert, Maryse; Popoff, Michel R; Martín-Satué, Mireia; Blasi, Juan

    2008-09-18

    Epsilon-toxin (epsilon-toxin), produced by Clostridium perfringens type D, is the main agent responsible for enterotoxaemia in livestock. Neurological disorders are a characteristic of the onset of toxin poisoning. Epsilon-Toxin accumulates specifically in the central nervous system, where it produces a glutamatergic-mediated excitotoxic effect. However, no detailed study of putative binding structures in the nervous tissue has been carried out to date. Here we attempt to identify specific acceptor moieties and cell targets for epsilon-toxin, not only in the mouse nervous system but also in the brains of sheep and cattle. An epsilon-toxin-GFP fusion protein was produced and used to incubate brain sections, which were then analyzed by confocal microscopy. The results clearly show specific binding of epsilon-toxin to myelin structures. epsilon-Prototoxin-GFP and epsilon-toxin-GFP, the inactive and active forms of the toxin, respectively, showed identical results. By means of pronase E treatment, we found that the binding was mainly associated to a protein component of the myelin. Myelinated peripheral nerve fibres were also stained by epsilon-toxin. Moreover, the binding to myelin was not only restricted to rodents, but was also found in humans, sheep and cattle. Curiously, in the brains of both sheep and cattle, the toxin strongly stained the vascular endothelium, a result that may explain the differences in potency and effect between species. Although the binding of epsilon-toxin to myelin does not directly explain its neurotoxic effect, this feature opens up a new line of enquiry into its mechanism of toxicity and establishes the usefulness of this toxin for the study of the mammalian nervous system. PMID:18406080

  17. IκB kinase 2 determines oligodendrocyte loss by non-cell-autonomous activation of NF-κB in the central nervous system

    PubMed Central

    Raasch, Jenni; Zeller, Nicolas; van Loo, Geert; Merkler, Doron; Mildner, Alexander; Erny, Daniel; Knobeloch, Klaus-Peter; Bethea, John R.; Waisman, Ari; Knust, Markus; Del Turco, Domenico; Deller, Thomas; Blank, Thomas; Priller, Josef; Brück, Wolfgang

    2011-01-01

    The IκB kinase complex induces nuclear factor kappa B activation and has recently been recognized as a key player of autoimmunity in the central nervous system. Notably, IκB kinase/nuclear factor kappa B signalling regulates peripheral myelin formation by Schwann cells, however, its role in myelin formation in the central nervous system during health and disease is largely unknown. Surprisingly, we found that brain-specific IκB kinase 2 expression is dispensable for proper myelin assembly and repair in the central nervous system, but instead plays a fundamental role for the loss of myelin in the cuprizone model. During toxic demyelination, inhibition of nuclear factor kappa B activation by conditional ablation of IκB kinase 2 resulted in strong preservation of central nervous system myelin, reduced expression of proinflammatory mediators and a significantly attenuated glial response. Importantly, IκB kinase 2 depletion in astrocytes, but not in oligodendrocytes, was sufficient to protect mice from myelin loss. Our results reveal a crucial role of glial cell-specific IκB kinase 2/nuclear factor kappa B signalling for oligodendrocyte damage during toxic demyelination. Thus, therapies targeting IκB kinase 2 function in non-neuronal cells may represent a promising strategy for the treatment of distinct demyelinating central nervous system diseases. PMID:21310728

  18. Structural and dynamical properties of reconstituted myelin sheaths in the presence of myelin proteins MBP and P2 studied by neutron scattering.

    PubMed

    Knoll, Wiebke; Peters, Judith; Kursula, Petri; Gerelli, Yuri; Ollivier, Jacques; Demé, Bruno; Telling, Mark; Kemner, Ewout; Natali, Francesca

    2014-01-21

    The myelin sheath is a tightly packed, multilayered membrane structure wrapped around selected nerve axons in the central and the peripheral nervous system. Because of its electrical insulation of the axons, which allows fast, saltatory nerve impulse conduction, myelin is crucial for the proper functioning of the vertebrate nervous system. A subset of myelin-specific proteins is well-defined, but their influence on membrane dynamics, i.e. myelin stability, has not yet been explored in detail. We investigated the structure and the dynamics of reconstituted myelin membranes on a pico- to nanosecond timescale, influenced by myelin basic protein (MBP) and myelin protein 2 (P2), using neutron diffraction and quasi-elastic neutron scattering. A model for the scattering function describing molecular lipid motions is suggested. Although dynamical properties are not affected significantly by MBP and P2 proteins, they act in a highly synergistic manner influencing the membrane structure. PMID:24651633

  19. Schwann cell autophagy, myelinophagy, initiates myelin clearance from injured nerves

    PubMed Central

    Gomez-Sanchez, Jose A.; Carty, Lucy; Iruarrizaga-Lejarreta, Marta; Palomo-Irigoyen, Marta; Varela-Rey, Marta; Griffith, Megan; Hantke, Janina; Macias-Camara, Nuria; Azkargorta, Mikel; Aurrekoetxea, Igor; De Juan, Virginia Gutiérrez; Jefferies, Harold B.J.; Aspichueta, Patricia; Elortza, Félix; Aransay, Ana M.; Martínez-Chantar, María L.; Baas, Frank; Mato, José M.; Mirsky, Rhona

    2015-01-01

    Although Schwann cell myelin breakdown is the universal outcome of a remarkably wide range of conditions that cause disease or injury to peripheral nerves, the cellular and molecular mechanisms that make Schwann cell–mediated myelin digestion possible have not been established. We report that Schwann cells degrade myelin after injury by a novel form of selective autophagy, myelinophagy. Autophagy was up-regulated by myelinating Schwann cells after nerve injury, myelin debris was present in autophagosomes, and pharmacological and genetic inhibition of autophagy impaired myelin clearance. Myelinophagy was positively regulated by the Schwann cell JNK/c-Jun pathway, a central regulator of the Schwann cell reprogramming induced by nerve injury. We also present evidence that myelinophagy is defective in the injured central nervous system. These results reveal an important role for inductive autophagy during Wallerian degeneration, and point to potential mechanistic targets for accelerating myelin clearance and improving demyelinating disease. PMID:26150392

  20. Characterization of the Shark Myelin Po Protein

    PubMed Central

    Rotenstein, L.; Herath, K.; Gould, R.M.; de Bellard, M.E.

    2008-01-01

    Myelin, the insulating sheath made by extensive plasma membrane wrappings is dependent on the presence of highly adhesive molecules that keep the two sides of the membrane in tight contact. The Po glycoprotein (Po) is the major component of the peripheral nervous system (PNS) myelin of mammals. The exact role that Po protein has played in the evolution of myelin is still unclear, but several phylogenetic observations point to it as a crucial component in the development of myelin as a multi-lamellar membrane structure. Sharks, which appeared in evolution about 400 million years ago, are the first fully myelinated organisms. In this study we set out to investigate the expression pattern of shark myelin Po as a way of understanding how it might have played a role in the evolution of myelin in the central nervous system. We found that shark have more than two isoforms (32, 28 and 25kD), and that some of these might not be fully functional because they lack the domains known for Po homophilic adhesion. PMID:18635929

  1. Strategies for myelin regeneration: lessons learned from development

    PubMed Central

    Bhatt, Abhay; Fan, Lir-Wan; Pang, Yi

    2014-01-01

    Myelin regeneration is indispensably important for patients suffering from several central nervous system (CNS) disorders such as multiple sclerosis (MS) and spinal cord injury (SCI), because it is not only essential for restoring neurophysiology, but also protects denuded axons for secondary degeneration. Understanding the cellular and molecular mechanisms underlying remyelination is critical for the development of remyelination-specific therapeutic approaches. As remyelination shares certain common mechanisms with developmental myelination, knowledge from study of developmental myelination contributes greatly to emerging myelin regeneration therapies, best evidenced as the recently developed human anti-Nogo receptor interacting protein-1 (LINGO-1) monoclonal antibodies to treat MS patients in clinical trials. PMID:25221590

  2. Plasmalogen phospholipids protect internodal myelin from oxidative damage.

    PubMed

    Luoma, Adrienne M; Kuo, Fonghsu; Cakici, Ozgur; Crowther, Michelle N; Denninger, Andrew R; Avila, Robin L; Brites, Pedro; Kirschner, Daniel A

    2015-07-01

    Reactive oxygen species (ROS) are implicated in a range of degenerative conditions, including aging, neurodegenerative diseases, and neurological disorders. Myelin is a lipid-rich multilamellar sheath that facilitates rapid nerve conduction in vertebrates. Given the high energetic demands and low antioxidant capacity of the cells that elaborate the sheaths, myelin is considered intrinsically vulnerable to oxidative damage, raising the question whether additional mechanisms prevent structural damage. We characterized the structural and biochemical basis of ROS-mediated myelin damage in murine tissues from both central nervous system (CNS) and peripheral nervous system (PNS). To determine whether ROS can cause structural damage to the internodal myelin, whole sciatic and optic nerves were incubated ex vivo with a hydroxyl radical-generating system consisting of copper (Cu), hydrogen peroxide (HP), and ortho-phenanthroline (OP). Quantitative assessment of unfixed tissue by X-ray diffraction revealed irreversible compaction of myelin membrane stacking in both sciatic and optic nerves. Incubation in the presence of the hydroxyl radical scavenger sodium formate prevented this damage, implicating hydroxyl radical species. Myelin membranes are particularly enriched in plasmalogens, a class of ether-linked phospholipids proposed to have antioxidant properties. Myelin in sciatic nerve from plasmalogen-deficient (Pex7 knockout) mice was significantly more vulnerable to Cu/OP/HP-mediated ROS-induced compaction than myelin from WT mice. Our results directly support the role of plasmalogens as endogenous antioxidants providing a defense that protects ROS-vulnerable myelin. PMID:25801291

  3. Prolonged myelination in human neocortical evolution

    PubMed Central

    Miller, Daniel J.; Duka, Tetyana; Stimpson, Cheryl D.; Schapiro, Steven J.; Baze, Wallace B.; McArthur, Mark J.; Fobbs, Archibald J.; Sousa, André M. M.; Šestan, Nenad; Wildman, Derek E.; Lipovich, Leonard; Kuzawa, Christopher W.; Hof, Patrick R.; Sherwood, Chet C.

    2012-01-01

    Nerve myelination facilitates saltatory action potential conduction and exhibits spatiotemporal variation during development associated with the acquisition of behavioral and cognitive maturity. Although human cognitive development is unique, it is not known whether the ontogenetic progression of myelination in the human neocortex is evolutionarily exceptional. In this study, we quantified myelinated axon fiber length density and the expression of myelin-related proteins throughout postnatal life in the somatosensory (areas 3b/3a/1/2), motor (area 4), frontopolar (prefrontal area 10), and visual (areas 17/18) neocortex of chimpanzees (N = 20) and humans (N = 33). Our examination revealed that neocortical myelination is developmentally protracted in humans compared with chimpanzees. In chimpanzees, the density of myelinated axons increased steadily until adult-like levels were achieved at approximately the time of sexual maturity. In contrast, humans displayed slower myelination during childhood, characterized by a delayed period of maturation that extended beyond late adolescence. This comparative research contributes evidence crucial to understanding the evolution of human cognition and behavior, which arises from the unfolding of nervous system development within the context of an enriched cultural environment. Perturbations of normal developmental processes and the decreased expression of myelin-related molecules have been related to psychiatric disorders such as schizophrenia. Thus, these species differences suggest that the human-specific shift in the timing of cortical maturation during adolescence may have implications for vulnerability to certain psychiatric disorders. PMID:23012402

  4. Prolonged myelination in human neocortical evolution.

    PubMed

    Miller, Daniel J; Duka, Tetyana; Stimpson, Cheryl D; Schapiro, Steven J; Baze, Wallace B; McArthur, Mark J; Fobbs, Archibald J; Sousa, André M M; Sestan, Nenad; Wildman, Derek E; Lipovich, Leonard; Kuzawa, Christopher W; Hof, Patrick R; Sherwood, Chet C

    2012-10-01

    Nerve myelination facilitates saltatory action potential conduction and exhibits spatiotemporal variation during development associated with the acquisition of behavioral and cognitive maturity. Although human cognitive development is unique, it is not known whether the ontogenetic progression of myelination in the human neocortex is evolutionarily exceptional. In this study, we quantified myelinated axon fiber length density and the expression of myelin-related proteins throughout postnatal life in the somatosensory (areas 3b/3a/1/2), motor (area 4), frontopolar (prefrontal area 10), and visual (areas 17/18) neocortex of chimpanzees (N = 20) and humans (N = 33). Our examination revealed that neocortical myelination is developmentally protracted in humans compared with chimpanzees. In chimpanzees, the density of myelinated axons increased steadily until adult-like levels were achieved at approximately the time of sexual maturity. In contrast, humans displayed slower myelination during childhood, characterized by a delayed period of maturation that extended beyond late adolescence. This comparative research contributes evidence crucial to understanding the evolution of human cognition and behavior, which arises from the unfolding of nervous system development within the context of an enriched cultural environment. Perturbations of normal developmental processes and the decreased expression of myelin-related molecules have been related to psychiatric disorders such as schizophrenia. Thus, these species differences suggest that the human-specific shift in the timing of cortical maturation during adolescence may have implications for vulnerability to certain psychiatric disorders. PMID:23012402

  5. [Parasitic diseases of the central nervous system].

    PubMed

    Schmutzhard, E

    2010-02-01

    Central nervous system infections and infestations by protozoa and helminths constitute a problem of increasing importance throughout all of central European and northern/western countries. This is partially due to the globalisation of our society, tourists and business people being more frequently exposed to parasitic infection/infestation in tropical countries than in moderate climate countries. On top of that, migrants may import chronic infestations and infections with parasitic pathogens, eventually also--sometimes exclusively--involving the nervous system. Knowledge of epidemiology, initial clinical signs and symptoms, diagnostic procedures as well as specific chemotherapeutic therapies and adjunctive therapeutic strategies is of utmost important in all of these infections and infestations of the nervous systems, be it by protozoa or helminths. This review lists, mainly in the form of tables, all possible infections and infestations of the nervous systems by protozoa and by helminths. Besides differentiating parasitic diseases of the nervous system seen in migrants, tourists etc., it is very important to have in mind that disease-related (e.g. HIV) or iatrogenic immunosuppression has led to the increased occurrence of a wide variety of parasitic infections and infestations of the nervous system (e. g. babesiosis, Chagas disease, Strongyloides stercoralis infestation, toxoplasmosis, etc.). PMID:20111855

  6. Degenerative disease affecting the nervous system.

    PubMed

    Eadie, M J

    1974-03-01

    The term "degenerative disease" is one which is rather widely used in relation to the nervous system and yet one which is rarely formally and carefully defined. The term appears to be applied to disorders of the nervous system which often occur in later life and which are of uncertain cause. In the Shorter Oxford Dictionary the word degeneration is defined as "a change of structure by which an organism, or an organ, assumes the form of a lower type". However this is not quite the sense in which the word is applied in human neuropathology, where it is conventional to restrict the use of the word to those organic disorders which are of uncertain or poorly understood cause and in which there is a deterioration or regression in the level of functioning of the nervous system. The concept of degenerative disorder is applied to other organs as well as to the brain, and as disease elsewhere in the body may affect the nervous system, it seems reasonable to include within the topic of degenerative disorder affecting the nervous system those conditions in which the nervous system is involved as a result of primary degenerations in other parts of the body. PMID:25026144

  7. Axonal Elongation into Peripheral Nervous System ``Bridges'' after Central Nervous System Injury in Adult Rats

    NASA Astrophysics Data System (ADS)

    David, Samuel; Aguayo, Albert J.

    1981-11-01

    The origin, termination, and length of axonal growth after focal central nervous system injury was examined in adult rats by means of a new experimental model. When peripheral nerve segments were used as ``bridges'' between the medulla and spinal cord, axons from neurons at both these levels grew approximately 30 millimeters. The regenerative potential of these central neurons seems to be expressed when the central nervous system glial environment is changed to that of the peripheral nervous system.

  8. Social Experience-Dependent Myelination: An Implication for Psychiatric Disorders

    PubMed Central

    Toritsuka, Michihiro; Kishimoto, Toshifumi

    2015-01-01

    Myelination is one of the strategies to promote the conduction velocity of axons in order to adjust to evolving environment in vertebrates. It has been shown that myelin formation depends on genetic programing and experience, including multiple factors, intracellular and extracellular molecules, and neuronal activities. Recently, accumulating studies have shown that myelination in the central nervous system changes more dynamically in response to neuronal activities and experience than expected. Among experiences, social experience-dependent myelination draws attention as one of the critical pathobiologies of psychiatric disorders. In this review, we summarize the mechanisms of neuronal activity-dependent and social experience-dependent myelination and discuss the contribution of social experience-dependent myelination to the pathology of psychiatric disorders. PMID:26078885

  9. Zeb2: A multifunctional regulator of nervous system development.

    PubMed

    Hegarty, Shane V; Sullivan, Aideen M; O'Keeffe, Gerard W

    2015-09-01

    Zinc finger E-box binding homeobox (Zeb) 2 is a transcription factor, identified due its ability to bind Smad proteins, and consists of multiple functional domains which interact with a variety of transcriptional co-effectors. The complex nature of the Zeb2, both at its genetic and protein levels, underlie its multifunctional properties, with Zeb2 capable of acting individually or as part of a transcriptional complex to repress, and occasionally activate, target gene expression. This review introduces Zeb2 as an essential regulator of nervous system development. Zeb2 is expressed in the nervous system throughout its development, indicating its importance in neurogenic and gliogenic processes. Indeed, mutation of Zeb2 has dramatic neurological consequences both in animal models, and in humans with Mowat-Wilson syndrome, which results from heterozygous ZEB2 mutations. The mechanisms by which Zeb2 regulates the induction of the neuroectoderm (CNS primordium) and the neural crest (PNS primordium) are reviewed herein. We then describe how Zeb2 acts to direct the formation, delamination, migration and specification of neural crest cells. Zeb2 regulation of the development of a number of cerebral regions, including the neocortex and hippocampus, are then described. The diverse molecular mechanisms mediating Zeb2-directed development of various neuronal and glial populations are reviewed. The role of Zeb2 in spinal cord and enteric nervous system development is outlined, while its essential function in CNS myelination is also described. Finally, this review discusses how the neurodevelopmental defects of Zeb2 mutant mice delineate the developmental dysfunctions underpinning the multiple neurological defects observed in Mowat-Wilson syndrome patients. PMID:26193487

  10. Evolution of myelin ultrastructure and the major structural myelin proteins.

    PubMed

    Inouye, Hideyo; Kirschner, Daniel A

    2016-06-15

    Myelin sheaths, as the specialized tissue wrapping the nerve fibers in the central and peripheral nervous systems (CNS and PNS), are responsible for rapid conduction of electrical signals in these fibers. We compare the nerve myelin sheaths of different phylogenetic origins-including mammal, rodent, bird, reptile, amphibian, lungfish, teleost, and elasmobranch-with respect to periodicities and inter-membrane separations at their cytoplasmic and extracellular appositions, and correlate these structural parameters with biochemical composition. P0 glycoprotein and P0-like proteins are present in PNS of terrestrial species or land vertebrates (Tetrapod) and in CNS and PNS of aquatic species. Proteolipid protein (PLP) is a major component only in the CNS myelin of terrestrial species and is involved in compaction of the extracellular apposition. The myelin structures of aquatic garfish and lungfish, which contain P0-like protein both in CNS and PNS, are similar to those of terrestrial species, indicating that they may be transitional organisms between water and land species. This article is part of a Special Issue entitled SI: Myelin Evolution. PMID:26519753

  11. Arf6 mediates Schwann cell differentiation and myelination.

    PubMed

    Torii, Tomohiro; Miyamoto, Yuki; Yamamoto, Masahiro; Ohbuchi, Katsuya; Tsumura, Hideki; Kawahara, Kazuko; Tanoue, Akito; Sakagami, Hiroyuki; Yamauchi, Junji

    2015-09-25

    During development of the peripheral nervous system (PNS), Schwann cells wrap neuronal axons, becoming the myelin sheaths that help axonal functions. While the intercellular signals controlling the myelination process between Schwann cells and peripheral neurons are well studied, the transduction of these signals in Schwann cells still remains elusive. Here, we show that Arf6, an Arf protein of the small GTPase family, is involved in promoting the myelination process. Knockdown of Arf6 with the small-interfering (si)RNA in primary Schwann cells markedly decreases dibutyl-cyclic AMP-induced myelin marker protein expression, indicating that Arf6 plays a role in differentiation-like phenotypic changes. To obtain in vivo evidence, we generated small-hairpin (sh)RNA transgenic mice targeting Arf6 for Schwann cells. Transgenic mice exhibited reduced myelin thickness compared to littermate controls, consistent with the defective myelin formation observed in the transgenic mouse-derived Schwann cell and neuronal culture system. Transgenic mice also exhibited decreased phosphorylation of myelination-related signaling molecules such as Akt kinase cascade proteins as well as downregulation of myelin marker proteins. These results suggest that signaling through Arf6 is required for Schwann cell myelination, adding Arf6 to the list of intracellular signaling molecules involved in the myelination process. PMID:26277388

  12. Autoantibodies to nervous system-specific proteins are elevated in sera of flight crew members: biomarkers for nervous system injury.

    PubMed

    Abou-Donia, Mohamed B; Abou-Donia, Martha M; ElMasry, Eman M; Monro, Jean A; Mulder, Michel F A

    2013-01-01

    This descriptive study reports the results of assays performed to detect circulating autoantibodies in a panel of 7 proteins associated with the nervous system (NS) in sera of 12 healthy controls and a group of 34 flight crew members including both pilots and attendants who experienced adverse effects after exposure to air emissions sourced to the ventilation system in their aircrafts and subsequently sought medical attention. The proteins selected represent various types of proteins present in nerve cells that are affected by neuronal degeneration. In the sera samples from flight crew members and healthy controls, immunoglobin (IgG) was measured using Western blotting against neurofilament triplet proteins (NFP), tubulin, microtubule-associated tau proteins (tau), microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and glial S100B protein. Significant elevation in levels of circulating IgG-class autoantibodies in flight crew members was found. A symptom-free pilot was sampled before symptoms and then again afterward. This pilot developed clinical problems after flying for 45 h in 10 d. Significant increases in autoantibodies were noted to most of the tested proteins in the serum of this pilot after exposure to air emissions. The levels of autoantibodies rose with worsening of his condition compared to the serum sample collected prior to exposure. After cessation of flying for a year, this pilot's clinical condition improved, and eventually he recovered and his serum autoantibodies against nervous system proteins decreased. The case study with this pilot demonstrates a temporal relationship between exposure to air emissions, clinical condition, and level of serum autoantibodies to nervous system-specific proteins. Overall, these results suggest the possible development of neuronal injury and gliosis in flight crew members anecdotally exposed to cabin air emissions containing organophosphates. Thus, increased

  13. Local Nitric Oxide Production in Viral and Autoimmune Diseases of the Central Nervous System

    NASA Astrophysics Data System (ADS)

    Hooper, D. Craig; Tsuyoshi Ohnishi, S.; Kean, Rhonda; Numagami, Yoshihiro; Dietzschold, Bernhard; Koprowski, Hilary

    1995-06-01

    Because of the short half-life of NO, previous studies implicating NO in central nervous system pathology during infection had to rely on the demonstration of elevated levels of NO synthase mRNA or enzyme expression or NO metabolites such as nitrate and nitrite in the infected brain. To more definitively investigate the potential causative role of NO in lesions of the central nervous system in animals infected with neurotropic viruses or suffering from experimental allergic encephalitis, we have determined directly the levels of NO present in the central nervous system of such animals. Using spin trapping of NO and electron paramagnetic resonance spectroscopy, we confirm here that copious amounts of NO (up to 30-fold more than control) are elaborated in the brains of rats infected with rabies virus or borna disease virus, as well as in the spinal cords of rats that had received myelin basic protein-specific T cells.

  14. Adult myelination: wrapping up neuronal plasticity

    PubMed Central

    O’Rourke, Megan; Gasperini, Robert; Young, Kaylene M.

    2014-01-01

    In this review, we outline the major neural plasticity mechanisms that have been identified in the adult central nervous system (CNS), and offer a perspective on how they regulate CNS function. In particular we examine how myelin plasticity can operate alongside neurogenesis and synaptic plasticity to influence information processing and transfer in the mature CNS. PMID:25221576

  15. Myelin alters the inflammatory phenotype of macrophages by activating PPARs

    PubMed Central

    2013-01-01

    Background Foamy macrophages, containing myelin degradation products, are abundantly found in active multiple sclerosis (MS) lesions. Recent studies have described an altered phenotype of macrophages after myelin internalization. However, mechanisms by which myelin affects the phenotype of macrophages and how this phenotype influences lesion progression remain unclear. Results We demonstrate that myelin as well as phosphatidylserine (PS), a phospholipid found in myelin, reduce nitric oxide production by macrophages through activation of peroxisome proliferator-activated receptor β/δ (PPARβ/δ). Furthermore, uptake of PS by macrophages, after intravenous injection of PS-containing liposomes (PSLs), suppresses the production of inflammatory mediators and ameliorates experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The protective effect of PSLs in EAE animals is associated with a reduced immune cell infiltration into the central nervous system and decreased splenic cognate antigen specific proliferation. Interestingly, PPARβ/δ is activated in foamy macrophages in active MS lesions, indicating that myelin also activates PPARβ/δ in macrophages in the human brain. Conclusion Our data show that myelin modulates the phenotype of macrophages by PPAR activation, which may subsequently dampen MS lesion progression. Moreover, our results suggest that myelin-derived PS mediates PPARβ/δ activation in macrophages after myelin uptake. The immunoregulatory impact of naturally-occurring myelin lipids may hold promise for future MS therapeutics. PMID:24252308

  16. The Injured Nervous System: A Darwinian Perspective

    PubMed Central

    Weil, Zachary M.; Norman, Greg J.; DeVries, A. Courtney; Nelson, Randy J.

    2008-01-01

    Much of the permanent damage that occurs in response to nervous system damage (trauma, infection, ischemia, etc.) is mediated by endogenous secondary processes that can contribute to cell death and tissue damage (excitotoxicity, oxidative damage and inflammation). For humans to evolve mechanisms to minimize secondary pathophysiological events following CNS injuries, selection must occur for individuals who survive such insults. Two major factors limit the selection for beneficial responses to CNS insults: for many CNS disease states the principal risk factor is advanced, post-reproductive age and virtually all severe CNS traumas are fatal in the absence of modern medical intervention. An alternative hypothesis for the persistence of apparently maladaptive responses to CNS damage is that the secondary exacerbation of damage is the result of unavoidable evolutionary constraints. That is, the nervous system could not function under normal conditions if the mechanisms that caused secondary damage (e.g., excitotoxicity) in response to injury were decreased or eliminated. However, some vertebrate species normally inhabit environments (e.g. hypoxia in underground burrows) that could potentially damage their nervous systems. Yet, profound neuroprotective mechanisms have evolved in these animals indicating that natural selection can occur for traits that protect animals from nervous system damage. Many of the secondary processes and regeneration-inhibitory factors that exacerbate injuries likely persist because they have been adaptive over evolutionary time in the healthy nervous system. Therefore, it remains important that researchers consider the role of the processes in the healthy or developing nervous system to understand how they become dysregulated following injury. PMID:18602443

  17. Neutron scattering from myelin revisited: bilayer asymmetry and water-exchange kinetics

    SciTech Connect

    Denninger, Andrew R.; Demé, Bruno; Cristiglio, Viviana; LeDuc, Géraldine; Feller, W. Bruce; Kirschner, Daniel A.

    2014-12-01

    The structure of internodal myelin in the rodent central and peripheral nervous systems has been determined using neutron diffraction. The kinetics of water exchange in these tissues is also described. Rapid nerve conduction in the central and peripheral nervous systems (CNS and PNS, respectively) of higher vertebrates is brought about by the ensheathment of axons with myelin, a lipid-rich, multilamellar assembly of membranes. The ability of myelin to electrically insulate depends on the regular stacking of these plasma membranes and on the presence of a number of specialized membrane-protein assemblies in the sheath, including the radial component, Schmidt–Lanterman incisures and the axo–glial junctions of the paranodal loops. The disruption of this fine-structure is the basis for many demyelinating neuropathies in the CNS and PNS. Understanding the processes that govern myelin biogenesis, maintenance and destabilization requires knowledge of myelin structure; however, the tight packing of internodal myelin and the complexity of its junctional specializations make myelin a challenging target for comprehensive structural analysis. This paper describes an examination of myelin from the CNS and PNS using neutron diffraction. This investigation revealed the dimensions of the bilayers and aqueous spaces of myelin, asymmetry between the cytoplasmic and extracellular leaflets of the membrane, and the distribution of water and exchangeable hydrogen in internodal multilamellar myelin. It also uncovered differences between CNS and PNS myelin in their water-exchange kinetics.

  18. Interplay between exercise and dietary fat modulates myelinogenesis in the central nervous system.

    PubMed

    Yoon, Hyesook; Kleven, Andrew; Paulsen, Alex; Kleppe, Laurel; Wu, Jianmin; Ying, Zhe; Gomez-Pinilla, Fernando; Scarisbrick, Isobel A

    2016-04-01

    Here we show that the interplay between exercise training and dietary fat regulates myelinogenesis in the adult central nervous system. Mice consuming high fat with coordinate voluntary running wheel exercise for 7weeks showed increases in the abundance of the major myelin membrane proteins, proteolipid (PLP) and myelin basic protein (MBP), in the lumbosacral spinal cord. Expression of MBP and PLP RNA, as well that for Myrf1, a transcription factor driving oligodendrocyte differentiation were also differentially increased under each condition. Furthermore, expression of IGF-1 and its receptor IGF-1R, known to promote myelinogenesis, were also increased in the spinal cord in response to high dietary fat or exercise training. Parallel increases in AKT signaling, a pro-myelination signaling intermediate activated by IGF-1, were also observed in the spinal cord of mice consuming high fat alone or in combination with exercise. Despite the pro-myelinogenic effects of high dietary fat in the context of exercise, high fat consumption in the setting of a sedentary lifestyle reduced OPCs and mature oligodendroglia. Whereas 7weeks of exercise training alone did not alter OPC or oligodendrocyte numbers, it did reverse reductions seen with high fat. Evidence is presented suggesting that the interplay between exercise and high dietary fat increase SIRT1, PGC-1α and antioxidant enzymes which may permit oligodendroglia to take advantage of diet and exercise-related increases in mitochondrial activity to yield increases in myelination despite higher levels of reactive oxygen species. PMID:26826016

  19. Expression pattern of neuregulin-1 type III during the development of the peripheral nervous system.

    PubMed

    Huang, Liang-Liang; Liu, Zhong-Yang; Huang, Jing-Hui; Luo, Zhuo-Jing

    2015-01-01

    Neuregulin-1 type III is a key regulator in Schwann cell proliferation, committing to a myelinating fate and regulating myelin sheath thickness. However, the expression pattern of neuregulin-1 type III in the peripheral nervous system during developmental periods (such as the premyelinating stage, myelinating stage and postmyelinating stage) has rarely been studied. In this study, dorsal root ganglia were isolated from rats between postnatal day 1 and postnatal day 56. The expression pattern of neuregulin-1 type III in dorsal root ganglia neurons at various developmental stages were compared by quantitative real-time polymerase chain reaction, western blot assay and immunofluorescent staining. The expression of neuregulin-1 type III mRNA reached its peak at postnatal day 3 and then stabilized at a relative high expression level from postnatal day 3 to postnatal day 56. The expression of neuregulin-1 type III protein increased gradually from postnatal day 1, reached a peak at postnatal day 28, and then decreased at postnatal day 56. Immunofluorescent staining results showed a similar tendency to western blot assay results. Experimental findings indicate that the expression of neuregulin-1 type III in rat dorsal root ganglion was increased during the premyelinating (from postnatal day 2 to postnatal day 5) and myelinating stage (from postnatal day 5 to postnatal day 10), but remained at a high level in the postmyelinating stage (after postnatal day 10). PMID:25788922

  20. The effect of space radiation of the nervous system

    NASA Astrophysics Data System (ADS)

    Gauger, Grant E.; Tobias, Cornelius A.; Yang, Tracy; Whitney, Monroe

    The long-term effects of irradiation by accelerated heavy ions on the structure and function of the nervous system have not been studied extensively. Although the adult brain is relatively resistant to low LET radiation, cellular studies indicate that individual heavy ions can produce serious membrane lesions and multiple chromatin breaks. Capillary hemorrhages may follow high LET particle irradiation of the developing brain as high RBE effects. Evidence has been accumulating that the glial system and blood-brain barrier (BBB) are relatively sensitive to injury by ionizing radiation. While DNA repair is active in neural systems, it may be assumed that a significant portion of this molecular process is misrepair. Since the expression of cell lethality usually requires cell division, and nerve cells have an extremely low rate of division, it is possible that some of the characteristic changes of premature aging may represent a delayed effect of chromatin misrepair in brain. Altered microcirculation, decreased local metabolism, entanglement and reduction in synaptic density, premature loss of neurons, myelin degeneration, and glial proliferation are late signs of such injuries. HZE particles are very efficient in producing carcinogenic cell transformation, reaching a peak for iron particles. The promotion of viral transformation is also efficient up to an energy transfer of approximately 300 keV/micron. The RBE for carcinogenesis in nerve tissues remains unknown. On the basis of available information concerning HZE particle flux in interplanetary space, only general estimates of the magnitude of the effects of long-term spaceflight on some nervous system parameters may be constructed.

  1. Zebrafish as a model to investigate CNS myelination.

    PubMed

    Preston, Marnie A; Macklin, Wendy B

    2015-02-01

    Myelin plays a critical role in proper neuronal function by providing trophic and metabolic support to axons and facilitating energy-efficient saltatory conduction. Myelination is influenced by numerous molecules including growth factors, hormones, transmembrane receptors and extracellular molecules, which activate signaling cascades that drive cellular maturation. Key signaling molecules and downstream signaling cascades controlling myelination have been identified in cell culture systems. However, in vitro systems are not able to faithfully replicate the complex in vivo signaling environment that occurs during development or following injury. Currently, it remains time-consuming and expensive to investigate myelination in vivo in rodents, the most widely used model for studying mammalian myelination. As such, there is a need for alternative in vivo myelination models, particularly ones that can test molecular mechanisms without removing oligodendrocyte lineage cells from their native signaling environment or disrupting intercellular interactions with other cell types present during myelination. Here, we review the ever-increasing role of zebrafish in studies uncovering novel mechanisms controlling vertebrate myelination. These innovative studies range from observations of the behavior of single cells during in vivo myelination as well as mutagenesis- and pharmacology-based screens in whole animals. Additionally, we discuss recent efforts to develop novel models of demyelination and oligodendrocyte cell death in adult zebrafish for the study of cellular behavior in real time during repair and regeneration of damaged nervous systems. PMID:25263121

  2. Illuminating viral infections in the nervous system

    PubMed Central

    McGavern, Dorian B.; Kang, Silvia S.

    2016-01-01

    Viral infections are a major cause of human disease. Although most viruses replicate in peripheral tissues, some have developed unique strategies to move into the nervous system, where they establish acute or persistent infections. Viral infections in the central nervous system (CNS) can alter homeostasis, induce neurological dysfunction and result in serious, potentially life-threatening inflammatory diseases. This Review focuses on the strategies used by neurotropic viruses to cross the barrier systems of the CNS and on how the immune system detects and responds to viral infections in the CNS. A special emphasis is placed on immune surveillance of persistent and latent viral infections and on recent insights gained from imaging both protective and pathogenic antiviral immune responses. PMID:21508982

  3. Gravitational Study of the Central Nervous System

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.

    1983-01-01

    A series of experiments conducted at 1G are discussed with reference to the role of calcium ions in information processing by the central nervous system. A technique is described which allows thin sections of a mammalian hippocampus to be isolated while maintaining neural activity. Two experiments carried out in hypergravic fields are also addressed; one investigating altered stimulation in the auditory system, the other determining temperature regulation responses in hypergravic fields.

  4. Distinct profiles of myelin distribution along single axons of pyramidal neurons in the neocortex.

    PubMed

    Tomassy, Giulio Srubek; Berger, Daniel R; Chen, Hsu-Hsin; Kasthuri, Narayanan; Hayworth, Kenneth J; Vercelli, Alessandro; Seung, H Sebastian; Lichtman, Jeff W; Arlotta, Paola

    2014-04-18

    Myelin is a defining feature of the vertebrate nervous system. Variability in the thickness of the myelin envelope is a structural feature affecting the conduction of neuronal signals. Conversely, the distribution of myelinated tracts along the length of axons has been assumed to be uniform. Here, we traced high-throughput electron microscopy reconstructions of single axons of pyramidal neurons in the mouse neocortex and built high-resolution maps of myelination. We find that individual neurons have distinct longitudinal distribution of myelin. Neurons in the superficial layers displayed the most diversified profiles, including a new pattern where myelinated segments are interspersed with long, unmyelinated tracts. Our data indicate that the profile of longitudinal distribution of myelin is an integral feature of neuronal identity and may have evolved as a strategy to modulate long-distance communication in the neocortex. PMID:24744380

  5. Oligodendroglial membrane dynamics in relation to myelin biogenesis.

    PubMed

    Ozgen, Hande; Baron, Wia; Hoekstra, Dick; Kahya, Nicoletta

    2016-09-01

    In the central nervous system, oligodendrocytes synthesize a specialized membrane, the myelin membrane, which enwraps the axons in a multilamellar fashion to provide fast action potential conduction and to ensure axonal integrity. When compared to other membranes, the composition of myelin membranes is unique with its relatively high lipid to protein ratio. Their biogenesis is quite complex and requires a tight regulation of sequential events, which are deregulated in demyelinating diseases such as multiple sclerosis. To devise strategies for remedying such defects, it is crucial to understand molecular mechanisms that underlie myelin assembly and dynamics, including the ability of specific lipids to organize proteins and/or mediate protein-protein interactions in healthy versus diseased myelin membranes. The tight regulation of myelin membrane formation has been widely investigated with classical biochemical and cell biological techniques, both in vitro and in vivo. However, our knowledge about myelin membrane dynamics, such as membrane fluidity in conjunction with the movement/diffusion of proteins and lipids in the membrane and the specificity and role of distinct lipid-protein and protein-protein interactions, is limited. Here, we provide an overview of recent findings about the myelin structure in terms of myelin lipids, proteins and membrane microdomains. To give insight into myelin membrane dynamics, we will particularly highlight the application of model membranes and advanced biophysical techniques, i.e., approaches which clearly provide an added value to insight obtained by classical biochemical techniques. PMID:27141942

  6. Myelin Membrane Assembly Is Driven by a Phase Transition of Myelin Basic Proteins Into a Cohesive Protein Meshwork

    PubMed Central

    Aggarwal, Shweta; Snaidero, Nicolas; Pähler, Gesa; Frey, Steffen; Sánchez, Paula; Zweckstetter, Markus; Janshoff, Andreas; Schneider, Anja; Weil, Marie-Theres; Schaap, Iwan A. T.; Görlich, Dirk; Simons, Mikael

    2013-01-01

    Rapid conduction of nerve impulses requires coating of axons by myelin. To function as an electrical insulator, myelin is generated as a tightly packed, lipid-rich multilayered membrane sheath. Knowledge about the mechanisms that govern myelin membrane biogenesis is required to understand myelin disassembly as it occurs in diseases such as multiple sclerosis. Here, we show that myelin basic protein drives myelin biogenesis using weak forces arising from its inherent capacity to phase separate. The association of myelin basic protein molecules to the inner leaflet of the membrane bilayer induces a phase transition into a cohesive mesh-like protein network. The formation of this protein network shares features with amyloid fibril formation. The process is driven by phenylalanine-mediated hydrophobic and amyloid-like interactions that provide the molecular basis for protein extrusion and myelin membrane zippering. These findings uncover a physicochemical mechanism of how a cytosolic protein regulates the morphology of a complex membrane architecture. These results provide a key mechanism in myelin membrane biogenesis with implications for disabling demyelinating diseases of the central nervous system. PMID:23762018

  7. Myelin membrane assembly is driven by a phase transition of myelin basic proteins into a cohesive protein meshwork.

    PubMed

    Aggarwal, Shweta; Snaidero, Nicolas; Pähler, Gesa; Frey, Steffen; Sánchez, Paula; Zweckstetter, Markus; Janshoff, Andreas; Schneider, Anja; Weil, Marie-Theres; Schaap, Iwan A T; Görlich, Dirk; Simons, Mikael

    2013-01-01

    Rapid conduction of nerve impulses requires coating of axons by myelin. To function as an electrical insulator, myelin is generated as a tightly packed, lipid-rich multilayered membrane sheath. Knowledge about the mechanisms that govern myelin membrane biogenesis is required to understand myelin disassembly as it occurs in diseases such as multiple sclerosis. Here, we show that myelin basic protein drives myelin biogenesis using weak forces arising from its inherent capacity to phase separate. The association of myelin basic protein molecules to the inner leaflet of the membrane bilayer induces a phase transition into a cohesive mesh-like protein network. The formation of this protein network shares features with amyloid fibril formation. The process is driven by phenylalanine-mediated hydrophobic and amyloid-like interactions that provide the molecular basis for protein extrusion and myelin membrane zippering. These findings uncover a physicochemical mechanism of how a cytosolic protein regulates the morphology of a complex membrane architecture. These results provide a key mechanism in myelin membrane biogenesis with implications for disabling demyelinating diseases of the central nervous system. PMID:23762018

  8. Maintaining Genome Stability in the Nervous System

    PubMed Central

    McKinnon, Peter J.

    2014-01-01

    Active maintenance of genome stability is a prerequisite for the development and function of the nervous system. The high replication index during neurogenesis and the long life of mature neurons highlight the need for efficient cellular programs to safeguard genetic fidelity. Multiple DNA damage response pathways ensure that replication stress and other types of DNA lesions such as oxidative damage do not impact neural homeostasis. Numerous human neurologic syndromes result from defective DNA damage signaling and compromised genome integrity. These syndromes can involve different neuropathology, which highlights the diverse maintenance roles required for genome stability in the nervous system. Understanding how DNA damage signaling pathways promote neural development and preserve homeostasis is essential for understanding fundamental brain function. PMID:24165679

  9. Imaging the fetal central nervous system

    PubMed Central

    De Keersmaecker, B.; Claus, F.; De Catte, L.

    2011-01-01

    The low prevalence of fetal central nervous system anomalies results in a restricted level of exposure and limited experience for most of the obstetricians involved in prenatal ultrasound. Sonographic guidelines for screening the fetal brain in a systematic way will probably increase the detection rate and enhance a correct referral to a tertiary care center, offering the patient a multidisciplinary approach of the condition. This paper aims to elaborate on prenatal sonographic and magnetic resonance imaging (MRI) diagnosis and outcome of various central nervous system malformations. Detailed neurosonographic investigation has become available through high resolution vaginal ultrasound probes and the development of a variety of 3D ultrasound modalities e.g. ultrasound tomographic imaging. In addition, fetal MRI is particularly helpful in the detection of gyration and neurulation anomalies and disorders of the gray and white matter. PMID:24753859

  10. Regeneration in the nervous system with erythropoietin

    PubMed Central

    Maiese, Kenneth

    2015-01-01

    Globally, greater than 30 million individuals are afflicted with disorders of the nervous system accompanied by tens of thousands of new cases annually with limited, if any, treatment options. Erythropoietin (EPO) offers an exciting and novel therapeutic strategy to address both acute and chronic neurodegenerative disorders. EPO governs a number of critical protective and regenerative mechanisms that can impact apoptotic and autophagic programmed cell death pathways through protein kinase B (Akt), sirtuins, mammalian forkhead transcription factors, and wingless signaling. Translation of the cytoprotective pathways of EPO into clinically effective treatments for some neurodegenerative disorders has been promising, but additional work is necessary. In particular, development of new treatments with erythropoiesis-stimulating agents such as EPO brings several important challenges that involve detrimental vascular outcomes and tumorigenesis. Future work that can effectively and safely harness the complexity of the signaling pathways of EPO will be vital for the fruitful treatment of disorders of the nervous system. PMID:26549969

  11. Remodeling myelination: implications for mechanisms of neural plasticity

    PubMed Central

    Chang, Kae-Jiun; Redmond, Stephanie A; Chan, Jonah R

    2016-01-01

    One of the most significant paradigm shifts in membrane remodeling is the emerging view that membrane transformation is not exclusively controlled by cytoskeletal rearrangement, but also by biophysical constraints, adhesive forces, membrane curvature and compaction. One of the most exquisite examples of membrane remodeling is myelination. The advent of myelin was instrumental in advancing the nervous system during vertebrate evolution. With more rapid and efficient communication between neurons, faster and more complex computations could be performed in a given time and space. Our knowledge of how myelin-forming oligodendrocytes select and wrap axons has been limited by insufficient spatial and temporal resolution. By virtue of recent technological advances, progress has clarified longstanding controversies in the field. Here we review insights into myelination, from target selection to axon wrapping and membrane compaction, and discuss how understanding these processes has unexpectedly opened new avenues of insight into myelination-centered mechanisms of neural plasticity. PMID:26814588

  12. The Yin and Yang of YY1 in the nervous system.

    PubMed

    He, Ye; Casaccia-Bonnefil, Patrizia

    2008-08-01

    The transcription factor Yin Yang 1 (YY1) is a multifunctional protein that can activate or repress gene expression depending on the cellular context. YY1 is ubiquitously expressed and highly conserved between species. However, its role varies in diverse cell types and includes proliferation, differentiation, and apoptosis. This review will focus on the function of YY1 in the nervous system including its role in neural development, neuronal function, developmental myelination, and neurological disease. The multiple functions of YY1 in distinct cell types are reviewed and the possible mechanisms underlying the cell specificity for these functions are discussed. PMID:18485096

  13. Computed tomography of the central nervous system

    SciTech Connect

    Bentson, J.R.

    1982-01-01

    The objective of this chapter is to review the most pertinent articles published during the past year on the subject of computed tomography of the central nervous system. The chapter contains sections on pediatric computed tomography, and on the diagnostic use of CT in white matter disease, in infectious disease, for intracranial aneurysms, trauma, and intracranial tumors. Metrizamide flow studies and contrast enhancement are also examined. (KRM)

  14. Peripheral Nervous System Manifestations of Infectious Diseases

    PubMed Central

    Brizzi, Kate T.

    2014-01-01

    Infectious causes of peripheral nervous system (PNS) disease are underrecognized but potentially treatable. Heightened awareness educed by advanced understanding of the presentations and management of these infections can aid diagnosis and facilitate treatment. In this review, we discuss the clinical manifestations, diagnosis, and treatment of common bacterial, viral, and parasitic infections that affect the PNS. We additionally detail PNS side effects of some frequently used antimicrobial agents. PMID:25360209

  15. Zygomycotic invasion of the central nervous system.

    PubMed

    Sasaki, Tomoaki; Mineta, Masayuki; Kobayashi, Keigo; Ando, Masakatsu; Obata, Masahiko

    2010-06-01

    Zygomycosis is an opportunistic fungal infection that affects the central nervous system (CNS). In this report, we present three cases of zygomycosis with CNS involvement. In two patients zygomycosis developed after neurosurgery, and in the third patient zygomycosis developed after bone marrow transplantation for leukemia. All patients developed persistent fever and neurological deficits. They presented with progressive cerebral infarction accompanied by hemorrhage. Intraoperative findings and histopathological examinations revealed that zygomycotic hyphae caused mycotic aneurysm, vasculitis, and venous occlusion. PMID:20585927

  16. Stress, sex, and the enteric nervous system.

    PubMed

    Million, M; Larauche, M

    2016-09-01

    Made up of millions of enteric neurons and glial cells, the enteric nervous system (ENS) is in a key position to modulate the secretomotor function and visceral pain of the gastrointestinal tract. The early life developmental period, through which most of the ENS development occurs, is highly susceptible to microenvironmental perturbation. Over the past decade, accumulating evidence has shown the impact of stress and early life adversity (ELA) on host gastrointestinal pathophysiology. While most of the focus has been on alterations in brain structure and function, limited experimental work in rodents suggest that the enteric nervous system can also be directly affected, as shown by changes in the number, phenotype, and reactivity of enteric nerves. The work of Medland et al. in the current issue of this journal demonstrates that such alterations also occur in pigs, a larger mammalian species with high translational value to human. This work also highlights a sex-differential susceptibility of the ENS to the effect of ELA, which could contribute to the higher prevalence of GI disorders in women. In this mini-review, we will discuss the development and composition of the ENS and related gastrointestinal sensory motor and secretory functions. We will then focus on the influence of stress on the enteric nervous system, with a particular emphasis on neurodevelopmental changes. Finally, we will discuss the influence of sex on those parameters. PMID:27561694

  17. Comparative anatomy of the autonomic nervous system.

    PubMed

    Nilsson, Stefan

    2011-11-16

    This short review aims to point out the general anatomical features of the autonomic nervous systems of non-mammalian vertebrates. In addition it attempts to outline the similarities and also the increased complexity of the autonomic nervous patterns from fish to tetrapods. With the possible exception of the cyclostomes, perhaps the most striking feature of the vertebrate autonomic nervous system is the similarity between the vertebrate classes. An evolution of the complexity of the system can be seen, with the segmental ganglia of elasmobranchs incompletely connected longitudinally, while well developed paired sympathetic chains are present in teleosts and the tetrapods. In some groups the sympathetic chains may be reduced (dipnoans and caecilians), and have yet to be properly described in snakes. Cranial autonomic pathways are present in the oculomotor (III) and vagus (X) nerves of gnathostome fish and the tetrapods, and with the evolution of salivary and lachrymal glands in the tetrapods, also in the facial (VII) and glossopharyngeal (IX) nerves. PMID:20444653

  18. The molecular physiology of the axo-myelinic synapse.

    PubMed

    Micu, Ileana; Plemel, Jason R; Lachance, Celia; Proft, Juliane; Jansen, Andrew J; Cummins, Karen; van Minnen, Jan; Stys, Peter K

    2016-02-01

    Myelinated axons efficiently transmit information over long distances. The apposed myelin sheath confers favorable electrical properties, but restricts access of the axon to its extracellular milieu. Therefore, axonal metabolic support may require specific axo-myelinic communication. Here we explored activity-dependent glutamate-mediated signaling from axon to myelin. 2-Photon microscopy was used to image Ca(2+) changes in myelin in response to electrical stimulation of optic nerve axons ex vivo. We show that optic nerve myelin responds to axonal action potentials by a rise in Ca(2+) levels mediated by GluN2D and GluN3A-containing NMDA receptors. Glutamate is released from axons in a vesicular manner that is tetanus toxin-sensitive. The Ca(2+) source for vesicular fusion is provided by ryanodine receptors on axonal Ca(2+) stores, controlled by L-type Ca(2+) channels that sense depolarization of the internodal axolemma. Genetic ablation of GluN2D and GluN3A subunits results in greater lability of the compact myelin. Our results support the existence of a novel synapse between the axon and its myelin, suggesting a means by which traversing action potentials can signal the overlying myelin sheath. This may be an important physiological mechanism by which an axon can signal companion glia for metabolic support or adjust properties of its myelin in a dynamic manner. The axo-myelinic synapse may contribute to learning, while its disturbances may play a role in the pathophysiology of central nervous system disorders such as schizophrenia, where subtle abnormalities of myelinated white matter tracts have been shown in the human, or to frank demyelinating disorders such as multiple sclerosis. PMID:26515690

  19. Classical Neurotransmitters and their Significance within the Nervous System.

    ERIC Educational Resources Information Center

    Veca, A.; Dreisbach, J. H.

    1988-01-01

    Describes some of the chemical compounds involved in the nervous system and their roles in transmitting nerve signals. Discusses acetylcholine, dopamine, norepinephrine, serotonin, histamine, glycine, glutemate, and gamma-aminobutyric acid and their effects within the nervous system. (CW)

  20. NERVOUS-SYSTEM SPECIFIC PROTEINS AS BIOCHEMICAL INDICATORS OF NEUROTOXICITY

    EPA Science Inventory

    Recent advances in neuroimmunology and protein purification methodology have led to the identification of nervous-system specific proteins. Their intimate relationship to the cellular and functional heterogeneity of the nervous system, makes these proteins ideal biochemical marke...

  1. What Are the Parts of the Nervous System?

    MedlinePlus

    ... Research Planning Scientific Resources Research A-Z Topics Neuroscience Overview Condition Information Parts of the nervous system ... functions does the nervous system control? Why study neuroscience? What are the areas of neuroscience? NICHD Research ...

  2. Organization and maintenance of molecular domains in myelinated axons.

    PubMed

    Buttermore, Elizabeth D; Thaxton, Courtney L; Bhat, Manzoor A

    2013-05-01

    Over a century ago, Ramon y Cajal first proposed the idea of a directionality involved in nerve conduction and neuronal communication. Decades later, it was discovered that myelin, produced by glial cells, insulated axons with periodic breaks where nodes of Ranvier (nodes) form to allow for saltatory conduction. In the peripheral nervous system (PNS), Schwann cells are the glia that can either individually myelinate the axon from one neuron or ensheath axons of many neurons. In the central nervous system (CNS), oligodendrocytes are the glia that myelinate axons from different neurons. Review of more recent studies revealed that this myelination created polarized domains adjacent to the nodes. However, the molecular mechanisms responsible for the organization of axonal domains are only now beginning to be elucidated. The molecular domains in myelinated axons include the axon initial segment (AIS), where various ion channels are clustered and action potentials are initiated; the node, where sodium channels are clustered and action potentials are propagated; the paranode, where myelin loops contact with the axolemma; the juxtaparanode (JXP), where delayed-rectifier potassium channels are clustered; and the internode, where myelin is compactly wrapped. Each domain contains a unique subset of proteins critical for the domain's function. However, the roles of these proteins in axonal domain organization are not fully understood. In this review, we highlight recent advances on the molecular nature and functions of some of the components of each axonal domain and their roles in axonal domain organization and maintenance for proper neuronal communication. PMID:23404451

  3. The BIRN Project: Imaging the Nervous System

    SciTech Connect

    Ellisman, Mark

    2006-05-22

    The grand goal in neuroscience research is to understand how the interplay of structural, chemical and electrical signals in nervous tissue gives rise to behavior. Experimental advances of the past decades have given the individual neuroscientist an increasingly powerful arsenal for obtaining data, from the level of molecules to nervous systems. Scientists have begun the arduous and challenging process of adapting and assembling neuroscience data at all scales of resolution and across disciplines into computerized databases and other easily accessed sources. These databases will complement the vast structural and sequence databases created to catalogue, organize and analyze gene sequences and protein products. The general premise of the neuroscience goal is simple; namely that with 'complete' knowledge of the genome and protein structures accruing rapidly we next need to assemble an infrastructure that will facilitate acquisition of an understanding for how functional complexes operate in their cell and tissue contexts.

  4. The BIRN Project: Imaging the Nervous System

    SciTech Connect

    Ellisman, Mark

    2006-05-22

    The grand goal in neuroscience research is to understand how the interplay of structural, chemical and electrical signals in nervous tissue gives rise to behavior. Experimental advances of the past decades have given the individual neuroscientist an increasingly powerful arsenal for obtaining data, from the level of molecules to nervous systems. Scientists have begun the arduous and challenging process of adapting and assembling neuroscience data at all scales of resolution and across disciplines into computerized databases and other easily accessed sources. These databases will complement the vast structural and sequence databases created to catalogue, organize and analyze gene sequences and protein products. The general premise of the neuroscience goal is simple; namely that with "complete" knowledge of the genome and protein structures accruing rapidly we next need to assemble an infrastructure that will facilitate acquisition of an understanding for how functional complexes operate in their cell and tissue contexts.

  5. Lysophosphatidic Acid signaling in the nervous system.

    PubMed

    Yung, Yun C; Stoddard, Nicole C; Mirendil, Hope; Chun, Jerold

    2015-02-18

    The brain is composed of many lipids with varied forms that serve not only as structural components but also as essential signaling molecules. Lysophosphatidic acid (LPA) is an important bioactive lipid species that is part of the lysophospholipid (LP) family. LPA is primarily derived from membrane phospholipids and signals through six cognate G protein-coupled receptors (GPCRs), LPA1-6. These receptors are expressed on most cell types within central and peripheral nervous tissues and have been functionally linked to many neural processes and pathways. This Review covers a current understanding of LPA signaling in the nervous system, with particular focus on the relevance of LPA to both physiological and diseased states. PMID:25695267

  6. MHC-I and PirB Upregulation in the Central and Peripheral Nervous System following Sciatic Nerve Injury

    PubMed Central

    Bombeiro, André Luis; Thomé, Rodolfo; Oliveira Nunes, Sérgio Luiz; Monteiro Moreira, Bárbara; Verinaud, Liana; de Oliveira, Alexandre Leite Rodrigues

    2016-01-01

    Major histocompatibility complex class one (MHC-I) antigen-presenting molecules participate in central nervous system (CNS) synaptic plasticity, as does the paired immunoglobulin-like receptor B (PirB), an MHC-I ligand that can inhibit immune-cells and bind to myelin axon growth inhibitors. Based on the dual roles of both molecules in the immune and nervous systems, we evaluated their expression in the central and peripheral nervous system (PNS) following sciatic nerve injury in mice. Increased PirB and MHC-I protein and gene expression is present in the spinal cord one week after nerve transection, PirB being mostly expressed in the neuropile region. In the crushed nerve, MHC-I protein levels increased 2 weeks after lesion (wal) and progressively decreased over the next eight weeks. The same kinetics were observed for infiltrating cytotoxic T lymphocytes (CTLs) but not for PirB expression, which continuously increased. Both MHC-I and PirB were found in macrophages and Schwann cells but rarely in axons. Interestingly, at 8 wal, PirB was mainly restricted to the myelin sheath. Our findings reinforce the participation of MHC-I and PirB in CNS plasticity events. In contrast, opposing expression levels of these molecules were found in the PNS, so that MHC-I and PirB seem to be mostly implicated in antigen presentation to CTLs and axon myelination, respectively. PMID:27551751

  7. MHC-I and PirB Upregulation in the Central and Peripheral Nervous System following Sciatic Nerve Injury.

    PubMed

    Bombeiro, André Luis; Thomé, Rodolfo; Oliveira Nunes, Sérgio Luiz; Monteiro Moreira, Bárbara; Verinaud, Liana; Oliveira, Alexandre Leite Rodrigues de

    2016-01-01

    Major histocompatibility complex class one (MHC-I) antigen-presenting molecules participate in central nervous system (CNS) synaptic plasticity, as does the paired immunoglobulin-like receptor B (PirB), an MHC-I ligand that can inhibit immune-cells and bind to myelin axon growth inhibitors. Based on the dual roles of both molecules in the immune and nervous systems, we evaluated their expression in the central and peripheral nervous system (PNS) following sciatic nerve injury in mice. Increased PirB and MHC-I protein and gene expression is present in the spinal cord one week after nerve transection, PirB being mostly expressed in the neuropile region. In the crushed nerve, MHC-I protein levels increased 2 weeks after lesion (wal) and progressively decreased over the next eight weeks. The same kinetics were observed for infiltrating cytotoxic T lymphocytes (CTLs) but not for PirB expression, which continuously increased. Both MHC-I and PirB were found in macrophages and Schwann cells but rarely in axons. Interestingly, at 8 wal, PirB was mainly restricted to the myelin sheath. Our findings reinforce the participation of MHC-I and PirB in CNS plasticity events. In contrast, opposing expression levels of these molecules were found in the PNS, so that MHC-I and PirB seem to be mostly implicated in antigen presentation to CTLs and axon myelination, respectively. PMID:27551751

  8. Adhesion G protein-coupled receptors in nervous system development and disease.

    PubMed

    Langenhan, Tobias; Piao, Xianhua; Monk, Kelly R

    2016-09-01

    Members of the adhesion G protein-coupled receptor (aGPCR) class have emerged as crucial regulators of nervous system development, with important implications for human health and disease. In this Review, we discuss the current understanding of aGPCR functions during key steps in neural development, including cortical patterning, dendrite and synapse formation, and myelination. We focus on aGPCR modulation of cell-cell and cell-matrix interactions and signalling to control these varied aspects of neural development, and we discuss how impaired aGPCR function leads to neurological disease. We further highlight the emerging hypothesis that aGPCRs can be mechanically activated and the implications of this property in the nervous system. PMID:27466150

  9. Neuroimaging in Central Nervous System Lymphoma.

    PubMed

    Nabavizadeh, Seyed Ali; Vossough, Arastoo; Hajmomenian, Mehrdad; Assadsangabi, Reza; Mohan, Suyash

    2016-08-01

    Primary central nervous system lymphoma (PCNSL) is a rare aggressive high-grade type of extranodal lymphoma. PCNSL can have a variable imaging appearance and can mimic other brain disorders such as encephalitis, demyelination, and stroke. In addition to PCNSL, the CNS can be secondarily involved by systemic lymphoma. Computed tomography and conventional MRI are the initial imaging modalities to evaluate these lesions. Recently, however, advanced MRI techniques are more often used in an effort to narrow the differential diagnosis and potentially inform diagnostic and therapeutic decisions. PMID:27443998

  10. Viral Diseases of the Central Nervous System

    PubMed Central

    Swanson, Phillip A.; McGavern, Dorian B.

    2015-01-01

    Virus-induced diseases of the central nervous system (CNS) represent a significant burden to human health worldwide. The complexity of these diseases is influenced by the sheer number of different neurotropic viruses, the diverse routes of CNS entry, viral tropism, and the immune system. Using a combination of human pathological data and experimental animal models, we have begun to uncover many of the mechanisms that viruses use to enter the CNS and cause disease. This review highlights a selection of neurotropic viruses that infect the CNS and explores the means by which they induce neurological diseases such as meningitis, encephalitis, and myelitis. PMID:25681709

  11. The myelin oligodendrocyte glycoprotein directly binds nerve growth factor to modulate central axon circuitry

    PubMed Central

    Mei, Feng; Greenfield, Ariele; Jahn, Sarah; Shen, Yun-An A.; Reid, Hugh H.; McKemy, David D.

    2015-01-01

    Myelin oligodendrocyte glycoprotein (MOG) is a central nervous system myelin-specific molecule expressed on the outer lamellae of myelin. To date, the exact function of MOG has remained unknown, with MOG knockout mice displaying normal myelin ultrastructure and no apparent specific phenotype. In this paper, we identify nerve growth factor (NGF) as a binding partner for MOG and demonstrate that this interaction is capable of sequestering NGF from TrkA-expressing neurons to modulate axon growth and survival. Deletion of MOG results in aberrant sprouting of nociceptive neurons in the spinal cord. Binding of NGF to MOG may offer widespread implications into mechanisms that underlie pain pathways. PMID:26347141

  12. Macrophage-mediated myelin-related mitogenic factor for cultured Schwann cells.

    PubMed Central

    Baichwal, R R; Bigbee, J W; DeVries, G H

    1988-01-01

    Conditioned medium from cultured peritoneal macrophages that have phagocytosed a myelin membrane fraction is mitogenic for cultured Schwann cells. Production of the mitogenic supernatant was time- and dose-dependent with a maximal Schwann cell-proliferative response from supernatants after 48-hr incubation of cultured macrophages with myelin-enriched fraction (200 micrograms of protein per ml). The response was specific for myelin membrane: supernatants derived from macrophages incubated with axolemma, liver microsomes, polystyrene beads, or lipopolysaccharide were not mitogenic. Lysosomal processing of the myelin membrane was necessary for the production of the mitogenic factor, which was shown to be heat labile and trypsin sensitive. There was no species specificity because myelin membranes isolated from the central and peripheral nervous systems of rat, bovine, and human were equally potent in eliciting mitogenic supernatant. However, supernatants derived from central nervous system myelin membranes were two to three times more mitogenic than those obtained from peripheral nervous system fractions of the same species. Previous observations that myelin is mitogenic for cultured Schwann cells may, in part, involve the intermediate processing of myelin by macrophages that are present in Schwann cell cultures. These results suggest that macrophages play a crucial role in Schwann cell proliferation during Wallerian degeneration. Images PMID:3422757

  13. Photoplethysmographic measurements from central nervous system tissue

    NASA Astrophysics Data System (ADS)

    Phillips, J. P.; Kyriacou, P. A.; Chang, S. H.; Maney, K.; George, K. J.; Langford, R. M.

    2007-10-01

    A new system for measuring the oxygen saturation of blood within tissue has been developed, for a number of potential patient monitoring applications. This proof of concept project aims to address the unmet need of real-time measurement of oxygen saturation in the central nervous system (CNS) for patients recovering from neurosurgery or trauma, by developing a fibre optic signal acquisition system for internal placement through small apertures. The development and testing of a two-wavelength optical fibre reflectance photoplethysmography (PPG) system is described together with measurements in rats and preliminary results from a clinical trial of the system in patients undergoing neurosurgery. It was found that good quality red and near-infrared PPG signals could be consistently obtained from the rat spinal cord (n=6) and human cerebral cortex (n=4) using the fibre optic probe. These findings justify further development and clinical evaluation of this fibre optic system.

  14. The central nervous system of ascidian larvae.

    PubMed

    Hudson, Clare

    2016-09-01

    Ascidians are marine invertebrate chordates. Their tadpole larvae contain a dorsal tubular nervous system, resulting from the rolling up of a neural plate. Along the anterior-posterior (A-P) axis, the central nervous system (CNS) is organized into a sensory vesicle, neck, trunk ganglion, and tail nerve cord and consists of approximately only 330 cells, of which around 100 are thought to be neurons. The organization of distinct neuronal cell types and neurotransmitter gene expression within the CNS has been described. The unique developmental mode of ascidians, with a small number of cells and a fixed cell division pattern, allows individual cells to be traced throughout development. This feature has led to the complete documentation of the cell lineages of certain cell types in the CNS. Thus, a step-by-step understanding of nervous system development from the initial stages of neural induction to the neurogenesis of individual neurons is a feasible goal. The genetic control of neural fate induction and early neural plate patterning are now well understood. The molecular mechanisms specifying the cholinergic neurons of the trunk ganglion as well as the pigment cells of the sensory organs are also well elucidated. In addition, studies have begun on the morphogenetic processes of neurulation. Remaining challenges include building an embryonic atlas integrating gene expression patterns, cell lineage, and neuronal cell types as well as developing the gene regulatory networks of cell fate specification and integrating them with the genetic control of morphogenesis. WIREs Dev Biol 2016, 5:538-561. doi: 10.1002/wdev.239 For further resources related to this article, please visit the WIREs website. PMID:27328318

  15. Autoimmune demyelination in the central nervous system.

    PubMed

    Tabira, T

    1988-01-01

    Autoimmune demyelination was studied in EAE induced by active challenge or by transfer of effector T-cell lines or clones specific for myelin basic protein or proteolipid apoprotein. The following points became clear: (1) Proteolipid apoprotein is responsible for widespread demyelination; (2) demyelination is more significant in EAE with a more chronic disease process; (3) a single T-cell clone can mediate significant demyelination without the aid of recipient-derived T-cell populations; (4) the difference in vulnerability between axons and myelin may account for the T-cell-mediated demyelination; and (5) effector T-cell clones can be activated by allogeneic antigens. PMID:2462801

  16. Tamoxifen accelerates the repair of demyelinated lesions in the central nervous system

    PubMed Central

    Gonzalez, Ginez A.; Hofer, Matthias P.; Syed, Yasir A.; Amaral, Ana I.; Rundle, Jon; Rahman, Saifur; Zhao, Chao; Kotter, Mark R. N.

    2016-01-01

    Enhancing central nervous system (CNS) myelin regeneration is recognized as an important strategy to ameliorate the devastating consequences of demyelinating diseases such as multiple sclerosis. Previous findings have indicated that myelin proteins, which accumulate following demyelination, inhibit remyelination by blocking the differentiation of rat oligodendrocyte progenitor cells (OPCs) via modulation of PKCα. We therefore screened drugs for their potential to overcome this differentiation block. From our screening, tamoxifen emerges as a potent inducer of OPC differentiation in vitro. We show that the effects of tamoxifen rely on modulation of the estrogen receptors ERα, ERβ, and GPR30. Furthermore, we demonstrate that administration of tamoxifen to demyelinated rats in vivo accelerates remyelination. Tamoxifen is a well-established drug and is thus a promising candidate for a drug to regenerate myelin, as it will not require extensive safety testing. In addition, Tamoxifen plays an important role in biomedical research as an activator of inducible genetic models. Our results highlight the importance of appropriate controls when using such models. PMID:27554391

  17. Axon growth inhibition by RhoA/ROCK in the central nervous system

    PubMed Central

    Fujita, Yuki; Yamashita, Toshihide

    2014-01-01

    Rho kinase (ROCK) is a serine/threonine kinase and a downstream target of the small GTPase Rho. The RhoA/ROCK pathway is associated with various neuronal functions such as migration, dendrite development, and axonal extension. Evidence from animal studies reveals that RhoA/ROCK signaling is involved in various central nervous system (CNS) diseases, including optic nerve and spinal cord injuries, stroke, and neurodegenerative diseases. Given that RhoA/ROCK plays a critical role in the pathophysiology of CNS diseases, the development of therapeutic agents targeting this pathway is expected to contribute to the treatment of CNS diseases. The RhoA/ROCK pathway mediates the effects of myelin-associated axon growth inhibitors—Nogo, myelin-associated glycoprotein (MAG), oligodendrocyte-myelin glycoprotein (OMgp), and repulsive guidance molecule (RGM). Blocking RhoA/ROCK signaling can reverse the inhibitory effects of these molecules on axon outgrowth, and promotes axonal sprouting and functional recovery in animal models of CNS injury. To date, several RhoA/ROCK inhibitors have been under development or in clinical trials as therapeutic agents for neurological disorders. In this review, we focus on the RhoA/ROCK signaling pathway in neurological disorders. We also discuss the potential therapeutic approaches of RhoA/ROCK inhibitors for various neurological disorders. PMID:25374504

  18. Histoplasmosis of the central nervous system.

    PubMed Central

    Tan, V; Wilkins, P; Badve, S; Coppen, M; Lucas, S; Hay, R; Schon, F

    1992-01-01

    Histoplasma capsulatum infection of the central nervous system is extremely rare in the United Kingdom partly because the organism is not endemic. However, because the organism can remain quiescent in the lungs or the adrenal glands for over 40 years before dissemination, it increasingly needs to be considered in unexplained neurological disease particularly in people who lived in endemic areas as children. In this paper a rapidly progressive fatal myelopathy in an English man brought up in India was shown at necropsy to be due to histoplasmosis. The neurological features of this infection are reviewed. Images PMID:1640242

  19. Did the ctenophore nervous system evolve independently?

    PubMed

    Ryan, Joseph F

    2014-08-01

    Recent evidence supports the placement of ctenophores as the most distant relative to all other animals. This revised animal tree means that either the ancestor of all animals possessed neurons (and that sponges and placozoans apparently lost them) or that ctenophores developed them independently. Differentiating between these possibilities is important not only from a historical perspective, but also for the interpretation of a wide range of neurobiological results. In this short perspective paper, I review the evidence in support of each scenario and show that the relationship between the nervous system of ctenophores and other animals is an unsolved, yet tractable problem. PMID:24986234

  20. Physiology of the Autonomic Nervous System

    PubMed Central

    2007-01-01

    This manuscript discusses the physiology of the autonomic nervous system (ANS). The following topics are presented: regulation of activity; efferent pathways; sympathetic and parasympathetic divisions; neurotransmitters, their receptors and the termination of their activity; functions of the ANS; and the adrenal medullae. In addition, the application of this material to the practice of pharmacy is of special interest. Two case studies regarding insecticide poisoning and pheochromocytoma are included. The ANS and the accompanying case studies are discussed over 5 lectures and 2 recitation sections during a 2-semester course in Human Physiology. The students are in the first-professional year of the doctor of pharmacy program. PMID:17786266

  1. Vascularisation of the central nervous system

    PubMed Central

    Tata, Mathew; Ruhrberg, Christiana; Fantin, Alessandro

    2015-01-01

    The developing central nervous system (CNS) is vascularised through the angiogenic invasion of blood vessels from a perineural vascular plexus, followed by continued sprouting and remodelling until a hierarchical vascular network is formed. Remarkably, vascularisation occurs without perturbing the intricate architecture of the neurogenic niches or the emerging neural networks. We discuss the mouse hindbrain, forebrain and retina as widely used models to study developmental angiogenesis in the mammalian CNS and provide an overview of key cellular and molecular mechanisms regulating the vascularisation of these organs. PMID:26222953

  2. Catastrophic primary central nervous system vasculitis.

    PubMed

    Salvarani, Carlo; Brown, Robert D; Morris, Jonathan M; Huston, John; Hunder, Gene G

    2014-01-01

    Primary central nervous system vasculitis (PCNSV) is an uncommon condition that affects the brain and the spinal cord. It is heterogeneous in presenting characteristics and outcomes. We report a patient with a catastrophic rapidly progressive course refractory to intensive treatment with pulses of methylprednisolone and iv cyclophosphamide. The condition rapidly deteriorated and the patient died 6 weeks after presentation. Rapidly progressive PCNSV represents the worst end of the clinical spectrum of PCNSV. These patients are characterised by bilateral, multiple, large cerebral vessel lesions on angiograms and multiple bilateral cerebral infarctions. PMID:24854370

  3. Central Nervous System Complications of Oncologic Therapy.

    PubMed

    Hoeffner, Ellen G

    2016-08-01

    Traditional and newer agents used to treat cancer can cause significant toxicity to the central nervous system. MRI of the brain and spine is the imaging modality of choice for patients with cancer who develop neurologic symptoms. It is important to be aware of the agents that can cause neurotoxicity and their associated imaging findings so that patients are properly diagnosed and treated. In some instances conventional MRI may not be able to differentiate posttreatment effects from disease progression. In these instances advanced imaging techniques may be helpful, although further research is still needed. PMID:27444003

  4. Mold Infections of the Central Nervous System

    PubMed Central

    McCarthy, Matthew; Rosengart, Axel; Schuetz, Audrey N.; Kontoyiannis, Dimitrios P.; Walsh, Thomas J.

    2016-01-01

    The recent outbreak of exserohilum rostratum meningitis linked to epidural injections of methylprednisolone acetate has brought renewed attention to mold infections of the central nervous system (CNS).1 Although uncommon, these infections are often devastating and difficult to treat. This focused review of the epidemiologic aspects, clinical characteristics, and treatment of mold infections of the CNS covers a group of common pathogens: aspergillus, fusarium, and scedosporium species, molds in the order Mucorales, and dematiaceous molds. Infections caused by these pathogen groups have distinctive epidemiologic profiles, clinical manifestations, microbiologic characteristics, and therapeutic implications, all of which clinicians should understand. PMID:25006721

  5. [Sports injuries of the nervous system].

    PubMed

    Lang, C; Stefan, H

    1999-08-01

    Almost 1% of all Germans suffer sports injuries each year, almost 5% of all peripheral nerve lesions are due to sports. A review is given on various activities detailing the specific risks for traumata of the central and peripheral nervous system. Specifically these are volleyball, handball, basketball, American football, soccer, bowling, hockey, baseball, tennis, golf, javelin, fencing, wrestling, judo, boxing, running, jumping, dancing, mountain climbing, weight lifting, gymnastics, horse-back riding, swimming, rowing, skiing, skating, shooting, (motor) biking, car racing, flying, and sports for the disabled. The knowledge of typical traumata should enable the neurologist to rapidly and reliably recognize related lesions and to contribute to their prevention or improvement. PMID:10478302

  6. Formation of compact myelin is required for maturation of the axonal cytoskeleton

    NASA Technical Reports Server (NTRS)

    Brady, S. T.; Witt, A. S.; Kirkpatrick, L. L.; de Waegh, S. M.; Readhead, C.; Tu, P. H.; Lee, V. M.

    1999-01-01

    Although traditional roles ascribed to myelinating glial cells are structural and supportive, the importance of compact myelin for proper functioning of the nervous system can be inferred from mutations in myelin proteins and neuropathologies associated with loss of myelin. Myelinating Schwann cells are known to affect local properties of peripheral axons (de Waegh et al., 1992), but little is known about effects of oligodendrocytes on CNS axons. The shiverer mutant mouse has a deletion in the myelin basic protein gene that eliminates compact myelin in the CNS. In shiverer mice, both local axonal features like phosphorylation of cytoskeletal proteins and neuronal perikaryon functions like cytoskeletal gene expression are altered. This leads to changes in the organization and composition of the axonal cytoskeleton in shiverer unmyelinated axons relative to age-matched wild-type myelinated fibers, although connectivity and patterns of neuronal activity are comparable. Remarkably, transgenic shiverer mice with thin myelin sheaths display an intermediate phenotype indicating that CNS neurons are sensitive to myelin sheath thickness. These results indicate that formation of a normal compact myelin sheath is required for normal maturation of the neuronal cytoskeleton in large CNS neurons.

  7. Involvement of the Tyro3 receptor and its intracellular partner Fyn signaling in Schwann cell myelination.

    PubMed

    Miyamoto, Yuki; Torii, Tomohiro; Takada, Shuji; Ohno, Nobuhiko; Saitoh, Yurika; Nakamura, Kazuaki; Ito, Akihito; Ogata, Toru; Terada, Nobuo; Tanoue, Akito; Yamauchi, Junji

    2015-10-01

    During early development of the peripheral nervous system, Schwann cell precursors proliferate, migrate, and differentiate into premyelinating Schwann cells. After birth, Schwann cells envelop neuronal axons with myelin sheaths. Although some molecular mechanisms underlying myelination by Schwann cells have been identified, the whole picture remains unclear. Here we show that signaling through Tyro3 receptor tyrosine kinase and its binding partner, Fyn nonreceptor cytoplasmic tyrosine kinase, is involved in myelination by Schwann cells. Impaired formation of myelin segments is observed in Schwann cell neuronal cultures established from Tyro3-knockout mouse dorsal root ganglia (DRG). Indeed, Tyro3-knockout mice exhibit reduced myelin thickness. By affinity chromatography, Fyn was identified as the binding partner of the Tyro3 intracellular domain, and activity of Fyn is down-regulated in Tyro3-knockout mice, suggesting that Tyro3, acting through Fyn, regulates myelination. Ablating Fyn in mice results in reduced myelin thickness. Decreased myelin formation is observed in cultures established from Fyn-knockout mouse DRG. Furthermore, decreased kinase activity levels and altered expression of myelination-associated transcription factors are observed in these knockout mice. These results suggest the involvement of Tyro3 receptor and its binding partner Fyn in Schwann cell myelination. This constitutes a newly recognized receptor-linked signaling mechanism that can control Schwann cell myelination. PMID:26224309

  8. Nutritional stimulation of the autonomic nervous system.

    PubMed

    Luyer, Misha D P; Habes, Quirine; van Hak, Richard; Buurman, Wim

    2011-09-14

    Disturbance of the inflammatory response in the gut is important in several clinical diseases ranging from inflammatory bowel disease to postoperative ileus. Several feedback mechanisms exist that control the inflammatory cascade and avoid collateral damage. In the gastrointestinal tract, it is of particular importance to control the immune response to maintain the balance that allows dietary uptake and utilization of nutrients on one hand, while preventing invasion of bacteria and toxins on the other hand. The process of digestion and absorption of nutrients requires a relative hyporesponsiveness of the immune cells in the gut to luminal contents which is not yet fully understood. Recently, the autonomic nervous system has been identified as an important pathway to control local and systemic inflammation and gut barrier integrity. Activation of the pathway is possible via electrical or via pharmacological interventions, but is also achieved in a physiological manner by ingestion of dietary lipids. Administration of dietary lipids has been shown to be very effective in reducing the inflammatory cascade and maintaining intestinal barrier integrity in several experimental studies. This beneficial effect of nutrition on the inflammatory response and intestinal barrier integrity opens new therapeutic opportunities for treatment of certain gastrointestinal disorders. Furthermore, this neural feedback mechanism provides more insight in the relative hyporesponsiveness of the immune cells in the gut. Here, we will discuss the regulatory function of the autonomic nervous system on the inflammatory response and gut barrier function and the potential benefit in a clinical setting. PMID:22025873

  9. Nutritional stimulation of the autonomic nervous system

    PubMed Central

    Luyer, Misha DP; Habes, Quirine; van Hak, Richard; Buurman, Wim

    2011-01-01

    Disturbance of the inflammatory response in the gut is important in several clinical diseases ranging from inflammatory bowel disease to postoperative ileus. Several feedback mechanisms exist that control the inflammatory cascade and avoid collateral damage. In the gastrointestinal tract, it is of particular importance to control the immune response to maintain the balance that allows dietary uptake and utilization of nutrients on one hand, while preventing invasion of bacteria and toxins on the other hand. The process of digestion and absorption of nutrients requires a relative hyporesponsiveness of the immune cells in the gut to luminal contents which is not yet fully understood. Recently, the autonomic nervous system has been identified as an important pathway to control local and systemic inflammation and gut barrier integrity. Activation of the pathway is possible via electrical or via pharmacological interventions, but is also achieved in a physiological manner by ingestion of dietary lipids. Administration of dietary lipids has been shown to be very effective in reducing the inflammatory cascade and maintaining intestinal barrier integrity in several experimental studies. This beneficial effect of nutrition on the inflammatory response and intestinal barrier integrity opens new therapeutic opportunities for treatment of certain gastrointestinal disorders. Furthermore, this neural feedback mechanism provides more insight in the relative hyporesponsiveness of the immune cells in the gut. Here, we will discuss the regulatory function of the autonomic nervous system on the inflammatory response and gut barrier function and the potential benefit in a clinical setting. PMID:22025873

  10. A Novel Fluorescent Probe That Is Brain Permeable and Selectively Binds to Myelin

    PubMed Central

    Wu, Chunying; Tian, Donghua; Feng, Yue; Polak, Paul; Wei, Jingjun; Sharp, Adam; Stankoff, Bruno; Lubetzki, Catherine; Zalc, Bernard; Mufson, Elliott J.; Gould, Robert M.; Feinstein, Douglas L.; Wang, Yanming

    2011-01-01

    SUMMARY Myelin is a multilayered glial cell membrane that forms segmented sheaths around large-caliber axons of both the central nervous system (CNS) and peripheral nervous system (PNS). Myelin covering insures rapid and efficient transmission of nerve impulses. Direct visual assessment of local changes of myelin content in vivo could greatly facilitate diagnosis and therapeutic treatments of myelin-related diseases. Current histologic probes for the visualization of myelin are based on antibodies or charged histochemical reagents that do not enter the brain. We have developed a series of chemical compounds including (E,E)-1,4-bis(4′-aminostyryl)-2-dimethoxy-benzene termed BDB and the subject of this report, which readily penetrates the blood–brain barrier and selectively binds to the myelin sheath in brain. BDB selectively stains intact myelinated regions in wild-type mouse brain, which allows for delineation of cuprizone-induced demyelinating lesions in mouse brain. BDB can be injected IV into the brain and selectively detect demyelinating lesions in cuprizone-treated mice in situ. These studies justified further investigation of BDB as a potential myelin-imaging probe to monitor myelin pathology in vivo. PMID:16709728

  11. Noninvasive harmonics optical microscopy for long-term observation of embryonic nervous system development in vivo.

    PubMed

    Chen, Szu-Yu; Hsieh, Cho-Shuen; Chu, Shi-Wei; Lin, Cheng-Yung; Ko, Ching-Yi; Chen, Yi-Chung; Tsai, Huai-Jen; Hu, Chin-Hwa; Sun, Chi-Kuang

    2006-01-01

    Nervous system development is a complicated dynamic process, and many mechanisms remain unknown. By utilizing endogenous second-harmonic-generation as the contrast of polarized nerve fibers and third-harmonic-generation (THG) to reveal morphological changes, we have successfully observed the vertebrate embryonic nervous development from the very beginning based on a 1230-nm light source. The dynamic development of the nerve system within a live zebrafish embryo can be recorded continuously more than 20 hr without fluorescence markers. Since the THG process is not limited by the time of gene expression and differentiation as fluorescence-based techniques are, the observable stages can be advanced to the very beginning of the development process. The complete three-dimensional brain development from a neural plate to a neural tube can be uncovered with a submicron lateral resolution. We have, for the first time, also reported the generation of SHG from myelinated nerve fibers and the outer segment of the photoreceptors with a stacked membrane structure. Our study clearly indicates the fact that higher-harmonics-based optical microscopy has the strong potential to long-term in vivo study of the nervous system, including genetic disorders of the nervous system, axon pathfinding, neural regeneration, neural repair, and neural stem cell development. PMID:17092171

  12. Tuning PAK Activity to Rescue Abnormal Myelin Permeability in HNPP.

    PubMed

    Hu, Bo; Arpag, Sezgi; Zhang, Xuebao; Möbius, Wiebke; Werner, Hauke; Sosinsky, Gina; Ellisman, Mark; Zhang, Yang; Hamilton, Audra; Chernoff, Jonathan; Li, Jun

    2016-09-01

    Schwann cells in the peripheral nervous systems extend their membranes to wrap axons concentrically and form the insulating sheath, called myelin. The spaces between layers of myelin are sealed by myelin junctions. This tight insulation enables rapid conduction of electric impulses (action potentials) through axons. Demyelination (stripping off the insulating sheath) has been widely regarded as one of the most important mechanisms altering the action potential propagation in many neurological diseases. However, the effective nerve conduction is also thought to require a proper myelin seal through myelin junctions such as tight junctions and adherens junctions. In the present study, we have demonstrated the disruption of myelin junctions in a mouse model (Pmp22+/-) of hereditary neuropathy with liability to pressure palsies (HNPP) with heterozygous deletion of Pmp22 gene. We observed a robust increase of F-actin in Pmp22+/- nerve regions where myelin junctions were disrupted, leading to increased myelin permeability. These abnormalities were present long before segmental demyelination at the late phase of Pmp22+/- mice. Moreover, the increase of F-actin levels correlated with an enhanced activity of p21-activated kinase (PAK1), a molecule known to regulate actin polymerization. Pharmacological inhibition of PAK normalized levels of F-actin, and completely prevented the progression of the myelin junction disruption and nerve conduction failure in Pmp22+/- mice. Our findings explain how abnormal myelin permeability is caused in HNPP, leading to impaired action potential propagation in the absence of demyelination. We call it "functional demyelination", a novel mechanism upstream to the actual stripping of myelin that is relevant to many demyelinating diseases. This observation also provides a potential therapeutic approach for HNPP. PMID:27583434

  13. Central nervous system toxicity of metallic nanoparticles

    PubMed Central

    Feng, Xiaoli; Chen, Aijie; Zhang, Yanli; Wang, Jianfeng; Shao, Longquan; Wei, Limin

    2015-01-01

    Nanomaterials (NMs) are increasingly used for the therapy, diagnosis, and monitoring of disease- or drug-induced mechanisms in the human biological system. In view of their small size, after certain modifications, NMs have the capacity to bypass or cross the blood–brain barrier. Nanotechnology is particularly advantageous in the field of neurology. Examples may include the utilization of nanoparticle (NP)-based drug carriers to readily cross the blood–brain barrier to treat central nervous system (CNS) diseases, nanoscaffolds for axonal regeneration, nanoelectromechanical systems in neurological operations, and NPs in molecular imaging and CNS imaging. However, NPs can also be potentially hazardous to the CNS in terms of nano-neurotoxicity via several possible mechanisms, such as oxidative stress, autophagy, and lysosome dysfunction, and the activation of certain signaling pathways. In this review, we discuss the dual effect of NMs on the CNS and the mechanisms involved. The limitations of the current research are also discussed. PMID:26170667

  14. High-resolution fluorescence microscopy of myelin without exogenous probes.

    PubMed

    Christensen, Pia Crone; Brideau, Craig; Poon, Kelvin W C; Döring, Axinia; Yong, V Wee; Stys, Peter K

    2014-02-15

    Myelin is a critical element of the central and peripheral nervous systems of all higher vertebrates. Any disturbance in the integrity of the myelin sheath interferes with the axon's ability to conduct action potentials. Thus, the study of myelin structure and biochemistry is critically important. Accurate and even staining of myelin is often difficult because of its lipid-rich nature and multiple tight membrane wraps, hindering penetration of immunoprobes. Here we show a method of visualizing myelin that is fast, inexpensive and reliable using the cross-linking fixative glutaraldehyde that produces strong, broad-spectrum auto-fluorescence in fixed tissue. Traditionally, effort is generally aimed at eliminating this auto-fluorescence. However, we show that this intrinsic signal, which is very photostable and particularly strong in glutaraldehyde-fixed myelin, can be exploited to visualize this structure to produce very detailed images of myelin morphology. We imaged fixed rodent tissues from the central and peripheral nervous systems using spectral confocal microscopy to acquire high-resolution 3-dimensional images spanning the visual range of wavelengths (400-750 nm). Mathematical post-processing allows accurate and unequivocal separation of broadband auto-fluorescence from exogenous fluorescent probes such as DAPI and fluorescently-tagged secondary antibodies. We additionally show the feasibility of immunohistochemistry with antigen retrieval, which allows co-localization of proteins of interest together with detailed myelin morphology. The lysolecithin model of de- and remyelination is shown as an example of a practical application of this technique, which can be routinely applied when high-resolution microscopy of central or peripheral myelinated tracts is required. PMID:24188810

  15. Myelin regeneration in multiple sclerosis: targeting endogenous stem cells.

    PubMed

    Huang, Jeffrey K; Fancy, Stephen P J; Zhao, Chao; Rowitch, David H; Ffrench-Constant, Charles; Franklin, Robin J M

    2011-10-01

    Regeneration of myelin sheaths (remyelination) after central nervous system demyelination is important to restore saltatory conduction and to prevent axonal loss. In multiple sclerosis, the insufficiency of remyelination leads to the irreversible degeneration of axons and correlated clinical decline. Therefore, a regenerative strategy to encourage remyelination may protect axons and improve symptoms in multiple sclerosis. We highlight recent studies on factors that influence endogenous remyelination and potential promising pharmacological targets that may be considered for enhancing central nervous system remyelination. PMID:21904791

  16. Novel nervous system mechanisms in visceral pain.

    PubMed

    De Winter, B Y; Deiteren, A; De Man, J G

    2016-03-01

    Visceral hypersensitivity is an important factor underlying abdominal pain in functional gastrointestinal disorders such as irritable bowel syndrome (IBS) and can result from aberrant signaling from the gut to the brain or vice versa. Over the last two decades, research has identified several selective, intertwining pathways that underlie IBS-related visceral nociception, including specific receptors on afferent and efferent nerve fibers such as transient receptor potential channels (TRP) channels, opioid, and cannabinoid receptors. In this issue of Neurogastroenterology and Motility Gil et al. demonstrate that in an animal model with reduced descending inhibitory control, the sympathetic nervous system outflow is enhanced, contributing to visceral and somatic hypersensitivity. They also provide evidence that interfering with the activation of adrenergic receptors on sensory nerves can be an interesting new strategy to treat visceral pain in IBS. This mini-review places these findings in a broader perspective by providing an overview of promising novel mechanisms to alter the nervous control of visceral pain interfering with afferent or efferent neuronal signaling. PMID:26891060

  17. Central nervous system regeneration: from leech to opossum.

    PubMed

    Mladinic, M; Muller, K J; Nicholls, J G

    2009-06-15

    A major problem of neurobiology concerns the failure of injured mammalian spinal cord to repair itself. This review summarizes work done on two preparations in which regeneration can occur: the central nervous system of an invertebrate, the leech, and the spinal cord of an immature mammal, the opossum. The aim is to understand cellular and molecular mechanisms that promote and prevent regeneration. In the leech, an individual axon regrows successfully to re-establish connections with its synaptic target, while avoiding other neurons. Functions that were lost are thereby restored. Moreover, pairs of identified neurons become re-connected with appropriate synapses in culture. It has been shown that microglial cells and nitric oxide play key roles in leech CNS regeneration. In the opossum, the neonatal brain and spinal cord are so tiny that they survive well in culture. Fibres grow across spinal cord lesions in neonatal animals and in vitro, but axon regeneration stops abruptly between postnatal days 9 and 12. A comprehensive search has been made in spinal cords that can and cannot regenerate to identify genes and establish their locations. At 9 days, growth-promoting genes, their receptors and key transcription molecules are up-regulated. By contrast at 12 days, growth-inhibitory molecules associated with myelin are prominent. The complete sequence of the opossum genome and new methods for transfecting genes offer ways to determine which molecules promote and which inhibit spinal cord regeneration. These results lead to questions about how basic research on mechanisms of regeneration could be 'translated' into effective therapies for patients with spinal cord injuries. PMID:19525562

  18. Central nervous system phenotypes in craniosynostosis

    PubMed Central

    Aldridge, Kristina; Marsh, Jeffrey L; Govier, Daniel; Richtsmeier, Joan T

    2002-01-01

    Though reduction in the number of cranial elements through loss of a suture is a recognized trend in vertebrate evolution, the premature closure of cranial sutures in humans, craniosynostosis, is considered a pathological condition. Previous research on craniosynostosis has focused primarily on the skeletal phenotype, but the intimate relationship between the developing central nervous system (CNS) and skull is well documented. We investigate the morphology of the CNS in patients with isolated craniosynostosis through an analysis of cortical and subcortical features using 3-D magnetic resonance images (MRI). Results show that a distinct CNS phenotype can be defined for specific diagnostic categories. Many differences in CNS morphology observed in the patient samples may be anticipated based on skeletal morphology, but others are not reflected in the skull. We propose a developmental approach to determining the cause of premature suture fusion, which includes investigation of the craniofacial complex as a system, rather than study of isolated tissues. PMID:12171474

  19. Disruption of Cnp1 uncouples oligodendroglial functions in axonal support and myelination.

    PubMed

    Lappe-Siefke, Corinna; Goebbels, Sandra; Gravel, Michel; Nicksch, Eva; Lee, John; Braun, Peter E; Griffiths, Ian R; Nave, Klaus-Armin

    2003-03-01

    Myelination of axons by oligodendrocytes enables rapid impulse propagation in the central nervous system. But long-term interactions between axons and their myelin sheaths are poorly understood. Here we show that Cnp1, which encodes 2',3'-cyclic nucleotide phosphodiesterase in oligodendrocytes, is essential for axonal survival but not for myelin assembly. In the absence of glial cyclic nucleotide phosphodiesterase, mice developed axonal swellings and neurodegeneration throughout the brain, leading to hydrocephalus and premature death. But, in contrast to previously studied myelin mutants, the ultrastructure, periodicity and physical stability of myelin were not altered in these mice. Genetically, the chief function of glia in supporting axonal integrity can thus be completely uncoupled from its function in maintaining compact myelin. Oligodendrocyte dysfunction, such as that in multiple sclerosis lesions, may suffice to cause secondary axonal loss. PMID:12590258

  20. A zinc finger protein that regulates oligodendrocyte specification, migration and myelination in zebrafish.

    PubMed

    Sidik, Harwin; Talbot, William S

    2015-12-01

    Precise control of oligodendrocyte migration and development is crucial for myelination of axons in the central nervous system (CNS), but important questions remain unanswered about the mechanisms controlling these processes. In a zebrafish screen for myelination mutants, we identified a mutation in zinc finger protein 16-like (znf16l). znf16l mutant larvae have reduced myelin basic protein (mbp) expression and reduced CNS myelin. Marker, time-lapse and ultrastructural studies indicated that oligodendrocyte specification, migration and myelination are disrupted in znf16l mutants. Transgenic studies indicated that znf16l acts autonomously in oligodendrocytes. Expression of Zfp488 from mouse rescued mbp expression in znf16l mutants, indicating that these homologs have overlapping functions. Our results defined the function of a new zinc finger protein with specific function in oligodendrocyte specification, migration and myelination in the developing CNS. PMID:26459222

  1. Neuronal Activity Promotes Oligodendrogenesis and Adaptive Myelination in the Mammalian Brain

    PubMed Central

    Gibson, Erin M.; Purger, David; Mount, Christopher W.; Goldstein, Andrea K.; Lin, Grant L.; Wood, Lauren S.; Inema, Ingrid; Miller, Sarah E.; Bieri, Gregor; Zuchero, J. Bradley; Barres, Ben A.; Woo, Pamelyn J.; Vogel, Hannes; Monje, Michelle

    2014-01-01

    Myelination of the central nervous system requires the generation of functionally mature oligodendrocytes from oligodendrocyte precursor cells (OPCs). Electrically active neurons may influence OPC function and selectively instruct myelination of an active neural circuit. In this work, we use optogenetic stimulation of the premotor cortex in awake, behaving mice to demonstrate that neuronal activity elicits a mitogenic response of neural progenitor cells and OPCs, promotes oligodendrogenesis, and increases myelination within the deep layers of the premotor cortex and subcortical white matter. We further show that this neuronal activity–regulated oligodendrogenesis and myelination is associated with improved motor function of the corresponding limb. Oligodendrogenesis and myelination appear necessary for the observed functional improvement, as epigenetic blockade of oligodendrocyte differentiation and myelin changes prevents the activity-regulated behavioral improvement. PMID:24727982

  2. Oligodendroglia and Myelin in Neurodegenerative Diseases: More Than Just Bystanders?

    PubMed

    Ettle, Benjamin; Schlachetzki, Johannes C M; Winkler, Jürgen

    2016-07-01

    Oligodendrocytes, the myelinating cells of the central nervous system, mediate rapid action potential conduction and provide trophic support for axonal as well as neuronal maintenance. Their progenitor cell population is widely distributed in the adult brain and represents a permanent cellular reservoir for oligodendrocyte replacement and myelin plasticity. The recognition of oligodendrocytes, their progeny, and myelin as contributing factors for the pathogenesis and the progression of neurodegenerative disease has recently evolved shaping our understanding of these disorders. In the present review, we aim to highlight studies on oligodendrocytes and their progenitors in neurodegenerative diseases. We dissect oligodendroglial biology and illustrate evolutionary aspects in regard to their importance for neuronal functionality and maintenance of neuronal circuitries. After covering recent studies on oligodendroglia in different neurodegenerative diseases mainly in view of their function as myelinating cells, we focus on the alpha-synucleinopathy multiple system atrophy, a prototypical disorder with a well-defined oligodendroglial pathology. PMID:25966971

  3. Emerging infections of the central nervous system.

    PubMed

    Lyons, Jennifer; McArthur, Justin

    2013-12-01

    Emerging infections affecting the central nervous system often present as encephalitis and can cause substantial morbidity and mortality. Diagnosis requires not only careful history taking, but also the application of newly developed diagnostic tests. These diseases frequently occur in outbreaks stemming from viruses that have mutated from an animal host and gained the ability to infect humans. With globalization, this can translate to the rapid emergence of infectious clusters or the establishment of endemicity in previously naïve locations. Since these infections are often vector borne and effective treatments are almost uniformly lacking, prevention is at least as important as prompt diagnosis and institution of supportive care. In this review, we focus on some of the recent literature addressing emerging and resurging viral encephalitides in the United States and around the world-specifically, West Nile virus, dengue, polio, and cycloviruses. We also discuss new, or "emerging," techniques for the precise and rapid diagnosis of encephalitides. PMID:24136412

  4. Advances in Primary Central Nervous System Lymphoma.

    PubMed

    Patrick, Lauren B; Mohile, Nimish A

    2015-12-01

    Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma that is limited to the CNS. Although novel imaging techniques aid in discriminating lymphoma from other brain tumors, definitive diagnosis requires brain biopsy, vitreoretinal biopsy, or cerebrospinal fluid analysis. Survival rates in clinical studies have improved over the past 20 years due to the addition of high-dose methotrexate-based chemotherapy regimens to whole-brain radiotherapy. Long-term survival, however, is complicated by clinically devastating delayed neurotoxicity. Newer regimens are attempting to reduce or eliminate radiotherapy from first-line treatment with chemotherapy dose intensification. Significant advances have also been made in the fields of pathobiology and treatment, with more targeted treatments on the horizon. The rarity of the disease makes conducting of prospective clinical trials challenging, requiring collaborative efforts between institutions. This review highlights recent advances in the biology, detection, and treatment of PCNSL in immunocompetent patients. PMID:26475775

  5. The autonomic nervous system and renal physiology

    PubMed Central

    D’Elia, John A; Weinrauch, Larry A

    2013-01-01

    Research in resistant hypertension has again focused on autonomic nervous system denervation – 50 years after it had been stopped due to postural hypotension and availability of newer drugs. These (ganglionic blockers) drugs have all been similarly stopped, due to postural hypotension and yet newer antihypertensive agents. Recent demonstration of the feasibility of limited regional transcatheter sympathetic denervation has excited clinicians due to potential therapeutic implications. Standard use of ambulatory blood pressure recording equipment may alter our understanding of the diagnosis, potential treatment strategies, and health care outcomes – when faced with patients whose office blood pressure remains in the hypertensive range – while under treatment with three antihypertensive drugs at the highest tolerable doses, plus a diuretic. We review herein clinical relationships between autonomic function, resistant hypertension, current treatment strategies, and reflect upon the possibility of changes in our approach to resistant hypertension. PMID:24039445

  6. Varicella Zoster Virus in the Nervous System

    PubMed Central

    Gilden, Don; Nagel, Maria; Cohrs, Randall; Mahalingam, Ravi; Baird, Nicholas

    2015-01-01

    Varicella zoster virus (VZV) is a ubiquitous, exclusively human alphaherpesvirus. Primary infection usually results in varicella (chickenpox), after which VZV becomes latent in ganglionic neurons along the entire neuraxis. As VZV-specific cell-mediated immunity declines in elderly and immunocompromised individuals, VZV reactivates and causes herpes zoster (shingles), frequently complicated by postherpetic neuralgia. VZV reactivation also produces multiple serious neurological and ocular diseases, such as cranial nerve palsies, meningoencephalitis, myelopathy, and VZV vasculopathy, including giant cell arteritis, with or without associated rash. Herein, we review the clinical, laboratory, imaging, and pathological features of neurological complications of VZV reactivation as well as diagnostic tests to verify VZV infection of the nervous system. Updates on the physical state of VZV DNA and viral gene expression in latently infected ganglia, neuronal, and primate models to study varicella pathogenesis and immunity are presented along with innovations in the immunization of elderly individuals to prevent VZV reactivation. PMID:26918131

  7. VIIP: Central Nervous System (CNS) Modeling

    NASA Technical Reports Server (NTRS)

    Vera, Jerry; Mulugeta, Lealem; Nelson, Emily; Raykin, Julia; Feola, Andrew; Gleason, Rudy; Samuels, Brian; Ethier, C. Ross; Myers, Jerry

    2015-01-01

    Current long-duration missions to the International Space Station and future exploration-class missions beyond low-Earth orbit expose astronauts to increased risk of Visual Impairment and Intracranial Pressure (VIIP) syndrome. It has been hypothesized that the headward shift of cerebrospinal fluid (CSF) and blood in microgravity may cause significant elevation of intracranial pressure (ICP), which in turn may then induce VIIP syndrome through interaction with various biomechanical pathways. However, there is insufficient evidence to confirm this hypothesis. In this light, we are developing lumped-parameter models of fluid transport in the central nervous system (CNS) as a means to simulate the influence of microgravity on ICP. The CNS models will also be used in concert with the lumped parameter and finite element models of the eye described in the related IWS works submitted by Nelson et al., Feola et al. and Ethier et al.

  8. Antihypertensive drugs and the sympathetic nervous system.

    PubMed

    Del Colle, Sara; Morello, Fulvio; Rabbia, Franco; Milan, Alberto; Naso, Diego; Puglisi, Elisabetta; Mulatero, Paolo; Veglio, Franco

    2007-11-01

    Hypertension has been associated with several modifications in the function and regulation of the sympathetic nervous system (SNS). Although it is unclear whether this dysfunction is primary or secondary to the development of hypertension, these alterations are considered to play an important role in the evolution, maintenance, and development of hypertension and its target organ damage. Several pharmacological antihypertensive classes are currently available. The main drugs that have been clearly shown to affect SNS function are beta-blockers, alpha-blockers, and centrally acting drugs. On the contrary, the effects of ACE inhibitors (ACE-Is), AT1 receptor blockers (ARBs), calcium channel blockers (CCBs), and diuretics on SNS function remain controversial. These properties are pharmacologically and pathophysiologically relevant and should be considered in the choice of antihypertensive treatments and combination therapies in order to achieve, beyond optimal blood pressure control, a normalization of SNS physiology and the most effective prevention of target organ damage. PMID:18030057

  9. [Histopathology of central nervous system cavernomas].

    PubMed

    Mosnier, J-F; Brunon, J; Nuti, C

    2007-06-01

    Central nervous system cavernomas are vascular malformations, which occur in two circumstances: sporadic forms and familial autosomal dominant forms. The lesion consists of enlarged, closely packed vessels without interposition of brain parenchyma, surrounded by hemosiderin and gliosis, calcified in few cases. In 80% of sporadic forms the lesion is unique, multiple lesions are rare (median: 4). In familial forms the lesions are always multiple. Cavernomas are often associated with other vascular malformations, especially with venous developmental anomalies. The size of cavernomas is variable from 1 mm to several centimeters. About 70% of cases are supratentorial and 30% in the posterior fossa, particularly in the brain stem. Macroscopic and histopathological findings are typical and the diagnostic is generally easy. PMID:17498756

  10. Scaffolds for central nervous system tissue engineering

    NASA Astrophysics Data System (ADS)

    He, Jin; Wang, Xiu-Mei; Spector, Myron; Cui, Fu-Zhai

    2012-03-01

    Traumatic injuries to the brain and spinal cord of the central nervous system (CNS) lead to severe and permanent neurological deficits and to date there is no universally accepted treatment. Owing to the profound impact, extensive studies have been carried out aiming at reducing inflammatory responses and overcoming the inhibitory environment in the CNS after injury so as to enhance regeneration. Artificial scaffolds may provide a suitable environment for axonal regeneration and functional recovery, and are of particular importance in cases in which the injury has resulted in a cavitary defect. In this review we discuss development of scaffolds for CNS tissue engineering, focusing on mechanism of CNS injuries, various biomaterials that have been used in studies, and current strategies for designing and fabricating scaffolds.

  11. Environmentally related disorders of the nervous system

    SciTech Connect

    Baker, E.L.; Feldman, R.G.; French, J.G. )

    1990-03-01

    Specific physical and chemical agents found in the workplace and in the general environment are responsible for characteristic pathologic processes within the nervous system. It has been shown that many neurotoxic agents produce a dose-related spectrum of impairment ranging from mild slowing of nerve conducting velocity or prolongation in reaction time to neuropathy and frank encephalopathy. Clinical manifestations are determined by the agent involved, by the dose of exposure, the vulnerability of the cellular target, the ability of the organism to metabolize and excrete the agent, and the ability to repair damage. An occupational history, including evaluation of evidence of specific agents and job history, is a critical component in the clinical management of individuals with suspect neurotoxic disease. Environmentally-induced disorders can be prevented by appropriate environmental controls. Prevention of neurotoxic disease is a complex process requiring continuous involvement of public health agencies and strong scientific research.

  12. Gangliosides of the Vertebrate Nervous System.

    PubMed

    Schnaar, Ronald L

    2016-08-14

    Gangliosides, sialylated glycosphingolipids, found on all vertebrate cells and tissues, are major molecular determinants on the surfaces of vertebrate nerve cells. Composed of a sialylated glycan attached to a ceramide lipid, the same four structures-GM1, GD1a, GD1b, and GT1b-represent the vast majority (>90%) of gangliosides in the brains of all mammals and birds. Primarily found on the outer surface of the plasma membrane with their glycans facing outward, gangliosides associate laterally with each other, sphingomyelin, cholesterol, and select proteins in lipid rafts-the dynamic functional subdomains of the plasma membrane. The functions of gangliosides in the human nervous system are revealed by congenital mutations in ganglioside biosynthetic genes. Mutations in ST3GAL5, which codes for an enzyme early in brain ganglioside biosynthesis, result in an early-onset seizure disorder with profound motor and cognitive decay, whereas mutations in B4GALNT1, a gene encoding a later step, result in hereditary spastic paraplegia accompanied by intellectual deficits. The molecular functions of brain gangliosides include regulation of receptors in the same membrane via lateral (cis) associations and regulation of cell-cell recognition by trans interaction with ganglioside binding proteins on apposing cells. Gangliosides also affect the aggregation of Aβ (Alzheimer's disease) and α-synuclein (Parkinson's Disease). As analytical, biochemical, and genetic tools advance, research on gangliosides promises to reveal mechanisms of molecular control related to nerve and glial cell differentiation, neuronal excitability, axon outgrowth after nervous system injury, and protein folding in neurodegenerative diseases. PMID:27261254

  13. CNS Myelination Requires Cytoplasmic Dynein Function

    PubMed Central

    Yang, Michele L.; Shin, Jimann; Kearns, Christina A.; Langworthy, Melissa M.; Snell, Heather; Walker, Macie B.; Appel, Bruce

    2014-01-01

    Background Cytoplasmic dynein provides the main motor force for minus-end-directed transport of cargo on microtubules. Within the vertebrate central nervous system (CNS), proliferation, neuronal migration and retrograde axon transport are among the cellular functions known to require dynein. Accordingly, mutations of DYNC1H1, which encodes the heavy chain subunit of cytoplasmic dynein, have been linked to developmental brain malformations and axonal pathologies. Oligodendrocytes, the myelinating glial cell type of the CNS, migrate from their origins to their target axons and subsequently extend multiple long processes that ensheath axons with specialized insulating membrane. These processes are filled with microtubules, which facilitate molecular transport of myelin components. However, whether oligodendrocytes require cytoplasmic dynein to ensheath axons with myelin is not known. Results We identified a mutation of zebrafish dync1h1 in a forward genetic screen that caused a deficit of oligodendrocytes. Using in vivo imaging and gene expression analyses, we additionally found evidence that dync1h1 promotes axon ensheathment and myelin gene expression. Conclusions In addition to its well known roles in axon transport and neuronal migration, cytoplasmic dynein contributes to neural development by promoting myelination. PMID:25488883

  14. Neutron scattering from myelin revisited: bilayer asymmetry and water-exchange kinetics

    PubMed Central

    Denninger, Andrew R.; Demé, Bruno; Cristiglio, Viviana; LeDuc, Géraldine; Feller, W. Bruce; Kirschner, Daniel A.

    2014-01-01

    Rapid nerve conduction in the central and peripheral nervous systems (CNS and PNS, respectively) of higher vertebrates is brought about by the ensheathment of axons with myelin, a lipid-rich, multilamellar assembly of membranes. The ability of myelin to electrically insulate depends on the regular stacking of these plasma membranes and on the presence of a number of specialized membrane-protein assemblies in the sheath, including the radial component, Schmidt–Lanterman incisures and the axo–glial junctions of the paranodal loops. The disruption of this fine-structure is the basis for many demyelinating neuropathies in the CNS and PNS. Understanding the processes that govern myelin biogenesis, maintenance and destabilization requires knowledge of myelin structure; however, the tight packing of internodal myelin and the complexity of its junctional specializations make myelin a challenging target for comprehensive structural analysis. This paper describes an examination of myelin from the CNS and PNS using neutron diffraction. This investigation revealed the dimensions of the bilayers and aqueous spaces of myelin, asymmetry between the cytoplasmic and extracellular leaflets of the membrane, and the distribution of water and exchangeable hydrogen in internodal multilamellar myelin. It also uncovered differences between CNS and PNS myelin in their water-exchange kinetics. PMID:25478838

  15. Single myelin fiber imaging in living rodents without labeling by deep optical coherence microscopy

    NASA Astrophysics Data System (ADS)

    Ben Arous, Juliette; Binding, Jonas; Léger, Jean-François; Casado, Mariano; Topilko, Piotr; Gigan, Sylvain; Claude Boccara, A.; Bourdieu, Laurent

    2011-11-01

    Myelin sheath disruption is responsible for multiple neuropathies in the central and peripheral nervous system. Myelin imaging has thus become an important diagnosis tool. However, in vivo imaging has been limited to either low-resolution techniques unable to resolve individual fibers or to low-penetration imaging of single fibers, which cannot provide quantitative information about large volumes of tissue, as required for diagnostic purposes. Here, we perform myelin imaging without labeling and at micron-scale resolution with >300-μm penetration depth on living rodents. This was achieved with a prototype [termed deep optical coherence microscopy (deep-OCM)] of a high-numerical aperture infrared full-field optical coherence microscope, which includes aberration correction for the compensation of refractive index mismatch and high-frame-rate interferometric measurements. We were able to measure the density of individual myelinated fibers in the rat cortex over a large volume of gray matter. In the peripheral nervous system, deep-OCM allows, after minor surgery, in situ imaging of single myelinated fibers over a large fraction of the sciatic nerve. This allows quantitative comparison of normal and Krox20 mutant mice, in which myelination in the peripheral nervous system is impaired. This opens promising perspectives for myelin chronic imaging in demyelinating diseases and for minimally invasive medical diagnosis.

  16. 2',3'-cyclic nucleotide-3'-phosphodiesterase in the central nervous system is fatty-acylated by thioester linkage.

    PubMed

    Agrawal, H C; Sprinkle, T J; Agrawal, D

    1990-07-15

    2',3'-Cyclic nucleotide-3'-phosphodiesterase (CNP1 and CNP2 with Mr of 46,000 and 48,000, respectively) is the major enzyme of central nervous system myelin. It is associated with oligodendroglial plasma membrane and uncompacted myelin (myelin-like fraction), which are in contact with glial cytoplasm. Proteins of the myelin-like fraction were labeled with [3H]palmitic acid in brain slices from 17-day-old rats and immunoprecipitated with anti-CNP antiserum. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material revealed intense acylation of CNP1 and CNP2, and radioactivity was released by hydroxylamine. Palmitic acid was covalently bound to CNP because radioactivity was not removed by extraction of immunoprecipitated CNP with organic solvent or by boiling in sodium dodecyl sulfate and dithiothreitol. However, treatment of immunoprecipitated CNP with (a) hydroxylamine-released palmitohydroxamate and palmitic acid, (b) sodium borohydride-released hexadecanol, and (c) methanolic-KOH-released methyl palmitate. Synthesis, acylation, or transport of CNP was not affected by monensin or colchicine. However, acylation of CNP was inhibited 24-32% by cycloheximide. These results provide conclusive evidence that CNP1 and CNP2 are fatty acid acylated with palmitate through a thioester linkage and is posttranslationally modified sometime after synthesis. PMID:2164018

  17. Design, Synthesis, and Evaluation of Fluorinated Radioligands for Myelin Imaging.

    PubMed

    Tiwari, Anand Dev; Wu, Chunying; Zhu, Junqing; Zhang, Sheng; Zhu, Jinle; Wang, William R; Zhang, Jinming; Tatsuoka, Curtis; Matthews, Paul M; Miller, Robert H; Wang, Yanming

    2016-04-28

    Myelination is one of the fundamental processes in vertebrates. A major challenge is to quantitatively image myelin distribution in the central nervous system. For this reason, we designed and synthesized a series of fluorinated radioligands that can be radiolabeled as radiotracers for positron emission tomography (PET) imaging of myelin. These newly developed radioligands readily penetrate the blood-brain barrier and selectively bind to myelin membranes in the white matter region. Structure-activity relationship studies of such ligands suggested that optimal permeability could be achieved with calculated lipophilicty in the range of 3-4. After radiolabeling with fluorine-18, the brain uptake and retention of each radioligand were determined by microPET/CT imaging studies. These pharmacokinetic studies led us to identify a lead compound ([(18)F]FMeDAS, 32) with promising in vivo binding properties, which was subsequently validated by ex vivo autoradiography. PMID:27070324

  18. Prenatal diagnosis of central nervous system abnormalities.

    PubMed

    Angtuaco, E E; Angtuaco, T L; Angtuaco, E J

    1994-01-01

    Fetal anomalies have been the subject of innumerable publications both in the prenatal and neonatal literature. This has significantly increased in the last 10 years, mainly because of the advent of high-resolution ultrasound equipment and improvement of scanning techniques. In addition, guidelines issued by professional organizations involved in prenatal diagnosis have encouraged a more universal approach to the imaging and documentation of prenatal findings. The fetal central nervous system is the most frequently investigated organ system, mainly because of its easy accessibility and prominence even in the early stages of embryologic development. The biparietal diameter was the first fetal measurement to be widely used in determining gestational age. As investigators gained more experience, the appearance of ultrasound images achieved the resolution that allows direct comparisons with gross specimens and more recent sophisticated techniques of computed tomography and magnetic resonance imaging. Now endovaginal ultrasound can document early first trimester development and compare it to known embryologic landmarks. Interest in demonstrating the ultrasound counterpart of central nervous system structures in the early stages of development has resulted in a plethora of articles proving the unique ability of ultrasound in imaging the developing fetus. In view of all these developments, the beginning ultrasound specialist is faced with the challenge and responsibility not only of being familiar with the literature but also of the mastery of scanning techniques that allow accurate prenatal diagnosis. It is therefore helpful to review key developmental milestones in embryologic life and correlate them with the corresponding prenatal ultrasound appearance. In addition, the changing appearance of the developing fetus has created a need for a systematic approach in the evaluation of structures so routine protocols can be established. This has been the subject of other

  19. Cdon, a cell surface protein, mediates oligodendrocyte differentiation and myelination.

    PubMed

    Wang, Li-Chun; Almazan, Guillermina

    2016-06-01

    During central nervous system development, oligodendrocyte progenitors (OLPs) establish multiple branched processes and axonal contacts to initiate myelination. A complete understanding of the molecular signals implicated in cell surface interaction to initiate myelination/remyelination is currently lacking. The objective of our study was to assess whether Cdon, a cell surface protein that was shown to participate in muscle and neuron cell development, is involved in oligodendrocyte (OLG) differentiation and myelination. Here, we demonstrate that endogenous Cdon protein is expressed in OLPs, increasing in the early differentiation stages and decreasing in mature OLGs. Immunocytochemistry of endogenous Cdon showed localization on both OLG cell membranes and cellular processes exhibiting puncta- or varicosity-like structures. Cdon knockdown with siRNA decreased protein levels by 62% as well as two myelin-specific proteins, MBP and MAG. Conversely, overexpression of full-length rat Cdon increased myelin proteins in OLGs. The complexity of OLGs branching and contact point numbers with axons were also increased in Cdon overexpressing cells growing alone or in coculture with dorsal root ganglion neurons (DRGNs). Furthermore, myelination of DRGNs was decreased when OLPs were transfected with Cdon siRNA. Altogether, our results suggest that Cdon participates in OLG differentiation and myelination, most likely in the initial stages of development. GLIA 2016;64:1021-1033. PMID:26988125

  20. [Diagnostic imaging of central nervous system vasculitis].

    PubMed

    Yokota, Hajime; Yamada, Kei

    2015-03-01

    Vasculitis involving the central nervous system presents with infarction and hemorrhage, which are often nonspecific findings. Laboratory examinations are essential for diagnosis of vasculitis in addition to comprehensive and systematic review of the clinical course. Although most findings tend to be nonspecific, enhancement and thickening of the vascular wall indicate vasculitis. Visualization of the vascular wall requires selection of the appropriate imaging modality and mode of image acquisition. Contrast-enhanced CT, MRI, and FDG-PET are useful for visualizing large vessel vasculitis, while CT, MRI, and angiography are effective for medium vessel vasculitis. The use of ultrasound is limited to evaluating vessels on the body surface. Although relatively thick vessels can be demonstrated by angiography, complete survey of small vessels is difficult. Here, we summarize the characteristics of each imaging modality and imaging findings of typical vasculitides-Takayasu arteritis, giant cell arteritis, ANCA-associated vasculitis, Behçet's disease, primary angiitis of the CNS, and vasculitis associated with systemic disease. Differential diagnoses are also shown, including infective endocarditis, tuberculous meningitis, Ehlers-Danlos syndrome, and reversible cerebral vasoconstriction syndrome. PMID:25846439

  1. Molecular Disruptions of the Panglial Syncytium Block Potassium Siphoning and Axonal Saltatory Conduction: Pertinence to Neuromyelitis Optica and other Demyelinating Diseases of the Central Nervous System

    PubMed Central

    Rash, John E.

    2009-01-01

    The panglial syncytium maintains ionic conditions required for normal neuronal electrical activity in the central nervous system (CNS). Vital among these homeostatic functions is “potassium siphoning”, a process originally proposed to explain astrocytic sequestration and long-distance disposal of K+ released from unmyelinated axons during each action potential. Fundamentally different, more efficient processes are required in myelinated axons, where axonal K+ efflux occurs exclusively beneath and enclosed within the myelin sheath, precluding direct sequestration of K+ by nearby astrocytes. Molecular mechanisms for entry of excess K+ and obligatorily-associated osmotic water from axons into innermost myelin are not well characterized, whereas at the output end, axonally-derived K+ and associated osmotic water are known to be expelled by Kir4.1 and aquaporin-4 channels concentrated in astrocyte endfeet that surround capillaries and that form the glia limitans. Between myelin (input end) and astrocyte endfeet (output end) is a vast network of astrocyte “intermediaries” that are strongly inter-linked, including with myelin, by abundant gap junctions that disperse excess K+ and water throughout the panglial syncytium, thereby greatly reducing K+-induced osmotic swelling of myelin. Here, I review original reports that established the concept of potassium siphoning in unmyelinated CNS axons, summarize recent revolutions in our understanding of K+ efflux during axonal saltatory conduction, then describe additional components required by myelinated axons for a newly-described process of voltage-augmented “dynamic” potassium siphoning. If any of several molecular components of the panglial syncytium are compromised, K+ siphoning is blocked, myelin is destroyed, and axonal saltatory conduction ceases. Thus, a common thread linking several CNS demyelinating diseases is the disruption of potassium siphoning/water transport within the panglial syncytium. Continued

  2. Molecular disruptions of the panglial syncytium block potassium siphoning and axonal saltatory conduction: pertinence to neuromyelitis optica and other demyelinating diseases of the central nervous system.

    PubMed

    Rash, J E

    2010-07-28

    The panglial syncytium maintains ionic conditions required for normal neuronal electrical activity in the central nervous system (CNS). Vital among these homeostatic functions is "potassium siphoning," a process originally proposed to explain astrocytic sequestration and long-distance disposal of K(+) released from unmyelinated axons during each action potential. Fundamentally different, more efficient processes are required in myelinated axons, where axonal K(+) efflux occurs exclusively beneath and enclosed within the myelin sheath, precluding direct sequestration of K(+) by nearby astrocytes. Molecular mechanisms for entry of excess K(+) and obligatorily-associated osmotic water from axons into innermost myelin are not well characterized, whereas at the output end, axonally-derived K(+) and associated osmotic water are known to be expelled by Kir4.1 and aquaporin-4 channels concentrated in astrocyte endfeet that surround capillaries and that form the glia limitans. Between myelin (input end) and astrocyte endfeet (output end) is a vast network of astrocyte "intermediaries" that are strongly inter-linked, including with myelin, by abundant gap junctions that disperse excess K(+) and water throughout the panglial syncytium, thereby greatly reducing K(+)-induced osmotic swelling of myelin. Here, I review original reports that established the concept of potassium siphoning in unmyelinated CNS axons, summarize recent revolutions in our understanding of K(+) efflux during axonal saltatory conduction, then describe additional components required by myelinated axons for a newly-described process of voltage-augmented "dynamic" potassium siphoning. If any of several molecular components of the panglial syncytium are compromised, K(+) siphoning is blocked, myelin is destroyed, and axonal saltatory conduction ceases. Thus, a common thread linking several CNS demyelinating diseases is the disruption of potassium siphoning/water transport within the panglial syncytium

  3. Myelin-phagocytosing macrophages modulate autoreactive T cell proliferation

    PubMed Central

    2011-01-01

    Introduction Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease of the central nervous system (CNS) in which macrophages play a central role. Initially, macrophages where thought to be merely detrimental in MS, however, recent evidence suggests that their functional phenotype is altered following myelin phagocytosis. Macrophages that have phagocytosed myelin may be less inflammatory and may exert beneficial effects. The presence of myelin-containing macrophages in CNS-draining lymph nodes and perivascular spaces of MS patients suggests that these cells are ideally positioned to exert an immune regulatory role. Therefore we evaluated in this study the effect of myelin-phagocytosing macrophages on lymphocyte reactivity. Methods Thioglycolate-elicited rat peritoneal macrophages were loaded with myelin and cocultured with myelin-basic protein (MBP) or ovalbumin (OVA) reactive lymphocytes. Lymphocyte proliferation was determined by CFSE-labeling. The role of nitric oxide in regulating lymphocyte proliferation was assessed by addition of an inhibitor of inducible nitric oxide synthase to the coculture. In vivo immune regulation was investigated by treating MBP- and OVA-immunized animals subcutaneously with myelin. Cognate antigen specific lymphocyte proliferation and nitric oxide production were determined 9d post-immunization. Results In this study we demonstrate that myelin-phagocytosing macrophages inhibit TCR-triggered lymphocyte proliferation in an antigen-independent manner. The observed immune suppression is mediated by an increase in NO production by myelin-phagocytosing macrophages upon contact with lymphocytes. Additionally, myelin delivery to primarily CD169+ macrophages in popliteal lymph nodes of OVA-immunized animals results in a reduced cognate antigen specific proliferation. In contrast to OVA-immunized animals, lymphocytes from MBP-immunized animals displayed an increased proliferation after stimulation with their cognate antigen

  4. Ex vivo and in vivo coherent Raman imaging of the peripheral and central nervous system

    NASA Astrophysics Data System (ADS)

    Huff, Terry Brandon

    A hallmark of nervous system disorders is damage or degradation of the myelin sheath. Unraveling the mechanisms underlying myelin degeneration and repair represent one of the great challenges in medicine. This thesis work details the development and utilization of advanced optical imaging methods to gain insight into the structure and function of myelin in both healthy and diseased states in the in vivo environment. This first part of this thesis discusses ex vivo studies of the effects of high-frequency stimulation of spinal tissues on the structure of the node of Ranvier as investigated by coherent anti-Stokes Raman scattering (CARS) imaging (manuscript submitted to Journal of Neurosciece). Reversible paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation, beginning minutes after the onset and continuing for up to 10 min after stimulation was ceased. A mechanistic study revealed a Ca2+ dependent pathway: high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down. Also, the construction of dual-scanning CARS microscope for large area mapping of CNS tissues is detailed (Optics Express, 2008, 16:19396-193409). A confocal scanning head equipped with a rotating polygon mirror provides high speed, high resolution imaging and is coupled with a motorized sample stage to generate high-resolution large-area images of mouse brain coronal section and guinea pig spinal cord cross section. The polygon mirror decreases the mosaic acquisition time significantly without reducing the resolution of individual images. The ex vivo studies are then extended to in vivo imaging of mouse sciatic nerve tissue by CARS and second harmonic generation (SHG) imaging (Journal of Microscopy, 2007, 225: 175-182). Following a minimally invasive surgery to open the skin, CARS imaging of myelinated axons and SHG imaging of the

  5. Central nervous system stimulants and sport practice

    PubMed Central

    Avois, L; Robinson, N; Saudan, C; Baume, N; Mangin, P; Saugy, M

    2006-01-01

    Background and objectives Central nervous system (CNS) stimulants may be used to reduce tiredness and increase alertness, competitiveness, and aggression. They are more likely to be used in competition but may be used during training to increase the intensity of the training session. There are several potential dangers involving their misuse in contact sports. This paper reviews the three main CNS stimulants, ephedrine, amfetamine, and cocaine, in relation to misuse in sport. Methods Description of the pharmacology, actions, and side effects of amfetamine, cocaine, and ephedrine. Results CNS stimulants have psychotropic effects that may be perceived to be ergogenic. Some are prescription drugs, such as Ephedra alkaloids, and there are issues regarding their appropriate therapeutic use. Recently attention has been given to their widespread use by athletes, despite the lack of evidence regarding any ergogenic or real performance benefit, and their potentially serious side effects. Recreational drugs, some of which are illegal (cocaine, amfetamines), are commonly used by athletes and cause potential ergolytic effects. Overall, these drugs are important for their frequent use and mention in anti‐doping laboratories statistics and the media, and their potentially serious adverse effects. Conclusions Doping with CNS stimulants is a real public health problem and all sports authorities should participate in its prevention. Dissemination of information is essential to prevent doping in sport and to provide alternatives. Adequate training and education in this domain should be introduced. PMID:16799095

  6. Time Perception Mechanisms at Central Nervous System.

    PubMed

    Fontes, Rhailana; Ribeiro, Jéssica; Gupta, Daya S; Machado, Dionis; Lopes-Júnior, Fernando; Magalhães, Francisco; Bastos, Victor Hugo; Rocha, Kaline; Marinho, Victor; Lima, Gildário; Velasques, Bruna; Ribeiro, Pedro; Orsini, Marco; Pessoa, Bruno; Leite, Marco Antonio Araujo; Teixeira, Silmar

    2016-04-01

    The five senses have specific ways to receive environmental information and lead to central nervous system. The perception of time is the sum of stimuli associated with cognitive processes and environmental changes. Thus, the perception of time requires a complex neural mechanism and may be changed by emotional state, level of attention, memory and diseases. Despite this knowledge, the neural mechanisms of time perception are not yet fully understood. The objective is to relate the mechanisms involved the neurofunctional aspects, theories, executive functions and pathologies that contribute the understanding of temporal perception. Articles form 1980 to 2015 were searched by using the key themes: neuroanatomy, neurophysiology, theories, time cells, memory, schizophrenia, depression, attention-deficit hyperactivity disorder and Parkinson's disease combined with the term perception of time. We evaluated 158 articles within the inclusion criteria for the purpose of the study. We conclude that research about the holdings of the frontal cortex, parietal, basal ganglia, cerebellum and hippocampus have provided advances in the understanding of the regions related to the perception of time. In neurological and psychiatric disorders, the understanding of time depends on the severity of the diseases and the type of tasks. PMID:27127597

  7. Time Perception Mechanisms at Central Nervous System

    PubMed Central

    Fontes, Rhailana; Ribeiro, Jéssica; Gupta, Daya S.; Machado, Dionis; Lopes-Júnior, Fernando; Magalhães, Francisco; Bastos, Victor Hugo; Rocha, Kaline; Marinho, Victor; Lima, Gildário; Velasques, Bruna; Ribeiro, Pedro; Orsini, Marco; Pessoa, Bruno; Leite, Marco Antonio Araujo; Teixeira, Silmar

    2016-01-01

    The five senses have specific ways to receive environmental information and lead to central nervous system. The perception of time is the sum of stimuli associated with cognitive processes and environmental changes. Thus, the perception of time requires a complex neural mechanism and may be changed by emotional state, level of attention, memory and diseases. Despite this knowledge, the neural mechanisms of time perception are not yet fully understood. The objective is to relate the mechanisms involved the neurofunctional aspects, theories, executive functions and pathologies that contribute the understanding of temporal perception. Articles form 1980 to 2015 were searched by using the key themes: neuroanatomy, neurophysiology, theories, time cells, memory, schizophrenia, depression, attention-deficit hyperactivity disorder and Parkinson’s disease combined with the term perception of time. We evaluated 158 articles within the inclusion criteria for the purpose of the study. We conclude that research about the holdings of the frontal cortex, parietal, basal ganglia, cerebellum and hippocampus have provided advances in the understanding of the regions related to the perception of time. In neurological and psychiatric disorders, the understanding of time depends on the severity of the diseases and the type of tasks. PMID:27127597

  8. Environmental effects on the central nervous system.

    PubMed Central

    Paulson, G W

    1977-01-01

    The central nervous system (CNS) is designed to respond to the environment and is peculiarly vulnerable to many of the influences found in the environment. Utilizing an anatomical classification (cortex, cerebellum, peripheral nerves) major toxins and stresses are reviewed with selections from recent references. Selective vulnerability of certain areas to particular toxins is apparent at all levels of the CNS, although the amount of damage produced by any noxious agent depends on the age and genetic substrate of the subject. It is apparent that the effects of certain well known and long respected environmental toxins such as lead, mercury, etc., deserve continued surveillance. In addition, the overwhelming impact on the CNS of social damages such as trauma, alcohol, and tobacco cannot be ignored by environmentalists. The effect of the hospital and therapeutic environment has become apparent in view of increased awareness of iatrogenic disorders. The need for particular laboratory tests, for example, examination of CSF and nerve conduction toxicity studies, is suggested. Epidemics such as the recent solvent neuropathies suggest a need for continued animal studies that are chronic, as well as acute evaluations when predicting the potential toxic effects of industrial compounds. PMID:202447

  9. Central Nervous System Immune Reconstitution Inflammatory Syndrome

    PubMed Central

    Boulware, David R.; Marais, Suzaan; Scriven, James; Wilkinson, Robert J.; Meintjes, Graeme

    2013-01-01

    Central nervous system immune reconstitution inflammatory syndrome (CNS-IRIS) develops in 9 %–47 % of persons with HIV infection and a CNS opportunistic infection who start antiretroviral therapy and is associated with a mortality rate of 13 %–75 %. These rates vary according to the causative pathogen. Common CNS-IRIS events occur in relation to Cryptococcus, tuberculosis (TB), and JC virus, but several other mycobacteria, fungi, and viruses have been associated with IRIS. IRIS symptoms often mimic the original infection, and diagnosis necessitates consideration of treatment failure, microbial resistance, and an additional neurological infection. These diagnostic challenges often delay IRIS diagnosis and treatment. Corticosteroids have been used to treat CNS-IRIS, with variable responses; the best supportive evidence exists for the treatment of TB-IRIS. Pathogenic mechanisms vary: Cryptococcal IRIS is characterized by a paucity of cerebrospinal inflammation prior to antiretroviral therapy, whereas higher levels of inflammatory markers at baseline predispose to TB meningitis IRIS. This review focuses on advances in the understanding of CNS-IRIS over the past 2 years. PMID:24173584

  10. Plants and the central nervous system.

    PubMed

    Carlini, E A

    2003-06-01

    This review article draws the attention to the many species of plants possessing activity on the central nervous system (CNS). In fact, they cover the whole spectrum of central activity such as psychoanaleptic, psycholeptic and psychodysleptic effects, and several of these plants are currently used in therapeutics to treat human ailments. Among the psychoanaleptic (stimulant) plants, those utilized by human beings to reduce body weight [Ephedra spp. (Ma Huang), Paullinia spp. (guaraná), Catha edulis Forssk. (khat)] and plants used to improve general health conditions (plant adaptogens) were scrutinized. Many species of hallucinogenic (psychodysleptic) plants are used by humans throughout the world to achieve states of mind distortions; among those, a few have been used for therapeutic purposes, such as Cannabis sativa L., Tabernanthe iboga Baill. and the mixture of Psychotria viridis Ruiz and Pav. and Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton. Plants showing central psycholeptic activities, such as analgesic or anxiolytic actions (Passiflora incarnata L., Valeriana spp. and Piper methysticum G. Forst.), were also analysed.Finally, the use of crude or semipurified extracts of such plants instead of the active substances seemingly responsible for their therapeutic effect is discussed. PMID:12895668

  11. In vivo peripheral nervous system insulin signaling

    PubMed Central

    Grote, Caleb W.; Ryals, Janelle M.; Wright, Douglas E.

    2014-01-01

    Alterations in peripheral nervous system (PNS) insulin support may contribute to diabetic neuropathy (DN); yet, PNS insulin signaling is not fully defined. Here, we investigated in vivo insulin signaling in the PNS and compared the insulin-responsiveness to that of muscle, liver, and adipose. Nondiabetic mice were administered increasing doses of insulin to define a dose response relationship between insulin and Akt activation in the DRG and sciatic nerve. Resulting EC50 doses were used to characterize the PNS insulin signaling time course and make comparisons between insulin signaling in the PNS and other peripheral tissues (i.e., muscle, liver, adipose). The results demonstrate that the PNS is responsive to insulin and that differences in insulin signaling pathway activation exist between PNS compartments. At a therapeutically relevant dose, Akt was activated in the muscle, liver, and adipose at 30 minutes, correlating with the changes in blood glucose levels. Interestingly, the sciatic nerve showed a similar signaling profile as insulin-sensitive tissues, however there was not a comparable activation in the DRG or spinal cord. These results present new evidence regarding PNS insulin signaling pathways in vivo and provide a baseline for studies investigating the contribution of disrupted PNS insulin signaling to DN pathogenesis. PMID:24028189

  12. Diabetes and the enteric nervous system.

    PubMed

    Chandrasekharan, B; Srinivasan, S

    2007-12-01

    Diabetes is associated with several changes in gastrointestinal (GI) motility and associated symptoms such as nausea, bloating, abdominal pain, diarrhoea and constipation. The pathogenesis of altered GI functions in diabetes is multifactorial and the role of the enteric nervous system (ENS) in this respect has gained significant importance. In this review, we summarize the research carried out on diabetes-related changes in the ENS. Changes in the inhibitory and excitatory enteric neurons are described highlighting the role of loss of inhibitory neurons in early diabetic enteric neuropathy. The functional consequences of these neuronal changes result in altered gastric emptying, diarrhoea or constipation. Diabetes can also affect GI motility through changes in intestinal smooth muscle or alterations in extrinsic neuronal control. Hyperglycaemia and oxidative stress play an important role in the pathophysiology of these ENS changes. Antioxidants to prevent or treat diabetic GI motility problems have therapeutic potential. Recent research on the nerve-immune interactions demonstrates inflammation-associated neurodegeneration which can lead to motility related problems in diabetes. PMID:17971027

  13. Early animal evolution and the origins of nervous systems

    PubMed Central

    Budd, Graham E.

    2015-01-01

    Understanding the evolution of early nervous systems is hazardous because we lack good criteria for determining homology between the systems of distant taxa; the timing of the evolutionary events is contested, and thus the relevant ecological and geological settings for them are also unclear. Here I argue that no simple approach will resolve the first issue, but that it remains likely that animals evolved relatively late, and that their nervous systems thus arose during the late Ediacaran, in a context provided by the changing planktonic and benthic environments of the time. The early trace fossil provides the most concrete evidence for early behavioural diversification, but it cannot simply be translated into increasing nervous system complexity: behavioural complexity does not map on a one-to-one basis onto nervous system complexity, both because of possible limitations to behaviour caused by the environment and because we know that even organisms without nervous systems are capable of relatively complex behaviour. PMID:26554037

  14. Early animal evolution and the origins of nervous systems.

    PubMed

    Budd, Graham E

    2015-12-19

    Understanding the evolution of early nervous systems is hazardous because we lack good criteria for determining homology between the systems of distant taxa; the timing of the evolutionary events is contested, and thus the relevant ecological and geological settings for them are also unclear. Here I argue that no simple approach will resolve the first issue, but that it remains likely that animals evolved relatively late, and that their nervous systems thus arose during the late Ediacaran, in a context provided by the changing planktonic and benthic environments of the time. The early trace fossil provides the most concrete evidence for early behavioural diversification, but it cannot simply be translated into increasing nervous system complexity: behavioural complexity does not map on a one-to-one basis onto nervous system complexity, both because of possible limitations to behaviour caused by the environment and because we know that even organisms without nervous systems are capable of relatively complex behaviour. PMID:26554037

  15. Marchi-positive myelinoid bodies at the transition between the central and the peripheral nervous system in some vertebrates.

    PubMed Central

    Corneliuson, O; Berthold, C H; Fabricius, C; Gatzinsky, K; Carlstedt, T

    1989-01-01

    The CNS-PNS (central nervous system-peripheral nervous system) transitional region of cranial and spinal nerve roots in some vertebrate species was analysed with respect to the occurrence and the distribution of myelinoid Marchi-positive bodies. Both cranial and spinal nerve roots contained more Marchi-positive bodies in their CNS than in their PNS segments. An accumulation of Marchi-positive bodies was usually noted just central to the CNS-PNS borderline. Comparisons between calibre spectra and Marchi index in the cat revealed a particularly high number of Marchi-positive bodies in nerve roots with a high content of myelinated fibres with diameters greater than or equal to 5 microns. Marchi-positive bodies were absent in CNS tissue lacking myelinated nerve fibres. CNS borderline internodes measuring between 200 and 300 microns in length were noted in fibres as thick as 15 microns in feline S1 ventral and dorsal roots. The general picture was similar in all analysed species. Noteworthy however, was the small difference in number of Marchi-positive bodies between CNS and PNS tissue in Xenopus. The chicken contained many myelinoid bodies of similar size and texture as the Marchi-positive bodies but without the Marchi-positive staining properties. The results show that normally occurring Marchi-positive bodies in the CNS are more numerous along paranodal segments than along mid-internodal segments of myelinated nerve fibres and thus support the hypothesis that Marchi-positive bodies are preferentially derived from paranodal myelin. Images Fig. 3 Fig. 4 PMID:2558098

  16. Influence of myelin proteins on the structure and dynamics of a model membrane with emphasis on the low temperature regime

    NASA Astrophysics Data System (ADS)

    Knoll, W.; Peters, J.; Kursula, P.; Gerelli, Y.; Natali, F.

    2014-11-01

    Myelin is an insulating, multi-lamellar membrane structure wrapped around selected nerve axons. Increasing the speed of nerve impulses, it is crucial for the proper functioning of the vertebrate nervous system. Human neurodegenerative diseases, such as multiple sclerosis, are linked to damage to the myelin sheath through demyelination. Myelin exhibits a well defined subset of myelin-specific proteins, whose influence on membrane dynamics, i.e., myelin flexibility and stability, has not yet been explored in detail. In a first paper [W. Knoll, J. Peters, P. Kursula, Y. Gerelli, J. Ollivier, B. Demé, M. Telling, E. Kemner, and F. Natali, Soft Matter 10, 519 (2014)] we were able to spotlight, through neutron scattering experiments, the role of peripheral nervous system myelin proteins on membrane stability at room temperature. In particular, the myelin basic protein and peripheral myelin protein 2 were found to synergistically influence the membrane structure while keeping almost unchanged the membrane mobility. Further insight is provided by this work, in which we particularly address the investigation of the membrane flexibility in the low temperature regime. We evidence a different behavior suggesting that the proton dynamics is reduced by the addition of the myelin basic protein accompanied by negligible membrane structural changes. Moreover, we address the importance of correct sample preparation and characterization for the success of the experiment and for the reliability of the obtained results.

  17. Influence of myelin proteins on the structure and dynamics of a model membrane with emphasis on the low temperature regime

    SciTech Connect

    Knoll, W.; Peters, J.; Kursula, P.; Gerelli, Y.; Natali, F.

    2014-11-28

    Myelin is an insulating, multi-lamellar membrane structure wrapped around selected nerve axons. Increasing the speed of nerve impulses, it is crucial for the proper functioning of the vertebrate nervous system. Human neurodegenerative diseases, such as multiple sclerosis, are linked to damage to the myelin sheath through demyelination. Myelin exhibits a well defined subset of myelin-specific proteins, whose influence on membrane dynamics, i.e., myelin flexibility and stability, has not yet been explored in detail. In a first paper [W. Knoll, J. Peters, P. Kursula, Y. Gerelli, J. Ollivier, B. Demé, M. Telling, E. Kemner, and F. Natali, Soft Matter 10, 519 (2014)] we were able to spotlight, through neutron scattering experiments, the role of peripheral nervous system myelin proteins on membrane stability at room temperature. In particular, the myelin basic protein and peripheral myelin protein 2 were found to synergistically influence the membrane structure while keeping almost unchanged the membrane mobility. Further insight is provided by this work, in which we particularly address the investigation of the membrane flexibility in the low temperature regime. We evidence a different behavior suggesting that the proton dynamics is reduced by the addition of the myelin basic protein accompanied by negligible membrane structural changes. Moreover, we address the importance of correct sample preparation and characterization for the success of the experiment and for the reliability of the obtained results.

  18. Myelin tetraspan family proteins but no non-tetraspan family proteins are present in the ascidian (Ciona intestinalis) genome.

    PubMed

    Gould, Robert M; Morrison, Hilary G; Gilland, Edwin; Campbell, Robert K

    2005-08-01

    Several of the proteins used to form and maintain myelin sheaths in the central nervous system (CNS) and the peripheral nervous system (PNS) are shared among different vertebrate classes. These proteins include one-to-several alternatively spliced myelin basic protein (MBP) isoforms in all sheaths, proteolipid protein (PLP) and DM20 (except in amphibians) in tetrapod CNS sheaths, and one or two protein zero (P0) isoforms in fish CNS and in all vertebrate PNS sheaths. Several other proteins, including 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP), myelin and lymphocyte protein (MAL), plasmolipin, and peripheral myelin protein 22 (PMP22; prominent in PNS myelin), are localized to myelin and myelin-associated membranes, though class distributions are less well studied. Databases with known and identified sequences of these proteins from cartilaginous and teleost fishes, amphibians, reptiles, birds, and mammals were prepared and used to search for potential homologs in the basal vertebrate, Ciona intestinalis. Homologs of lipophilin proteins, MAL/plasmolipin, and PMP22 were identified in the Ciona genome. In contrast, no MBP, P0, or CNP homologs were found. These studies provide a framework for understanding how myelin proteins were recruited during evolution and how structural adaptations enabled them to play key roles in myelination. PMID:16110093

  19. Melatonin Metabolism in the Central Nervous System

    PubMed Central

    Hardeland, Rüdiger

    2010-01-01

    The metabolism of melatonin in the central nervous system is of interest for several reasons. Melatonin enters the brain either via the pineal recess or by uptake from the blood. It has been assumed to be also formed in some brain areas. Neuroprotection by melatonin has been demonstrated in numerous model systems, and various attempts have been undertaken to counteract neurodegeneration by melatonin treatment. Several concurrent pathways lead to different products. Cytochrome P450 subforms have been demonstrated in the brain. They either demethylate melatonin to N-acetylserotonin, or produce 6-hydroxymelatonin, which is mostly sulfated already in the CNS. Melatonin is deacetylated, at least in pineal gland and retina, to 5-methoxytryptamine. N1-acetyl-N2-formyl-5-methoxykynuramine is formed by pyrrole-ring cleavage, by myeloperoxidase, indoleamine 2,3-dioxygenase and various non-enzymatic oxidants. Its product, N1-acetyl-5-methoxykynuramine, is of interest as a scavenger of reactive oxygen and nitrogen species, mitochondrial modulator, downregulator of cyclooxygenase-2, inhibitor of cyclooxygenase, neuronal and inducible NO synthases. Contrary to other nitrosated aromates, the nitrosated kynuramine metabolite, 3-acetamidomethyl-6-methoxycinnolinone, does not re-donate NO. Various other products are formed from melatonin and its metabolites by interaction with reactive oxygen and nitrogen species. The relative contribution of the various pathways to melatonin catabolism seems to be influenced by microglia activation, oxidative stress and brain levels of melatonin, which may be strongly changed in experiments on neuroprotection. Many of the melatonin metabolites, which may appear in elevated concentrations after melatonin administration, possess biological or pharmacological properties, including N-acetylserotonin, 5-methoxytryptamine and some of its derivatives, and especially the 5-methoxylated kynuramines. PMID:21358968

  20. Embryonic development of glial cells and myelin in the shark, Chiloscyllium punctatum

    PubMed Central

    Rotenstein, Lisa; Milanes, Anthony; Juarez, Marilyn; Reyes, Michelle; de Bellard, Maria Elena

    2009-01-01

    Glial cells are responsible for a wide range of functions in the nervous system of vertebrates. The myelinated nervous systems of extant elasmobranchs have the longest independent history of all gnathostomes. Much is known about the development of glia in other jawed vertebrates, but research in elasmobranchs is just beginning to reveal the mechanisms guiding neurodevelopment. This study examines the development of glial cells in the bamboo shark, Chiloscyllium punctatum, by identifying the expression pattern of several classic glial and myelin proteins. We show for the first time that glial development in the bamboo shark (Ch. punctamum) embryo follows closely the one observed in other vertebrates and that neural development seems to proceed at a faster rate in the PNS than in the CNS. In addition, we observed more myelinated tracts in the PNS than in the CNS, and as early as stage 32, suggesting that the ontogeny of myelin in sharks is closer to osteichthyans than agnathans. PMID:19733690

  1. G protein-coupled receptor 37 is a negative regulator of oligodendrocyte differentiation and myelination

    PubMed Central

    Yang, Hyun-Jeong; Vainshtein, Anna; Maik-Rachline, Galia; Peles, Elior

    2016-01-01

    While the formation of myelin by oligodendrocytes is critical for the function of the central nervous system, the molecular mechanism controlling oligodendrocyte differentiation remains largely unknown. Here we identify G protein-coupled receptor 37 (GPR37) as an inhibitor of late-stage oligodendrocyte differentiation and myelination. GPR37 is enriched in oligodendrocytes and its expression increases during their differentiation into myelin forming cells. Genetic deletion of Gpr37 does not affect the number of oligodendrocyte precursor cells, but results in precocious oligodendrocyte differentiation and hypermyelination. The inhibition of oligodendrocyte differentiation by GPR37 is mediated by suppression of an exchange protein activated by cAMP (EPAC)-dependent activation of Raf-MAPK-ERK1/2 module and nuclear translocation of ERK1/2. Our data suggest that GPR37 regulates central nervous system myelination by controlling the transition from early-differentiated to mature oligodendrocytes. PMID:26961174

  2. Carbon monoxide and the nervous system.

    PubMed

    Raub, J A; Benignus, V A

    2002-12-01

    Carbon monoxide (CO) is a colorless, tasteless, odorless, and non-irritating gas formed when carbon in fuel is not burned completely. It enters the bloodstream through the lungs and attaches to hemoglobin (Hb), the body's oxygen carrier, forming carboxyhemoglobin (COHb) and thereby reducing oxygen (O(2)) delivery to the body's organs and tissues. High COHb concentrations are poisonous. Central nervous system (CNS) effects in individuals suffering acute CO poisoning cover a wide range, depending on severity of exposure: headache, dizziness, weakness, nausea, vomiting, disorientation, confusion, collapse, and coma. At lower concentrations, CNS effects include reduction in visual perception, manual dexterity, learning, driving performance, and attention level. Earlier work is frequently cited to justify the statement that CO exposure sufficient to produce COHb levels of ca. 5% would be sufficient to produce visual sensitivity reduction and various neurobehavioral performance deficits. In a recent literature re-evaluation, however, the best estimate was that [COHb] would have to rise to 15-20% before a 10% reduction in any behavioral or visual measurement could be observed. This conclusion was based on (1) critical review of the literature on behavioral and sensory effects, (2) review and interpretation of the physiological effects of COHb on the CNS, (3) extrapolation from the effects of hypoxic hypoxia to the effects of CO hypoxia, and (4) extrapolation from rat behavioral effects of CO to humans. Also covered in this review article are effects of chronic CO exposure, the discovery of neuroglobin, a summary of the relatively new role for endogenous CO in neurotransmission and vascular homeostasis, groups which might be especially sensitive to CO, and recommendations on further research. The interested reader is directed to other published reviews of the literature on CO and historically seminal references that form our understanding of this ubiquitous gas. PMID

  3. Mechanosensitivity in the enteric nervous system

    PubMed Central

    Mazzuoli-Weber, Gemma; Schemann, Michael

    2015-01-01

    The enteric nervous system (ENS) autonomously controls gut muscle activity. Mechanosensitive enteric neurons (MEN) initiate reflex activity by responding to mechanical deformation of the gastrointestinal wall. MEN throughout the gut primarily respond to compression or stretch rather than to shear force. Some MEN are multimodal as they respond to compression and stretch. Depending on the region up to 60% of the entire ENS population responds to mechanical stress. MEN fire action potentials after mechanical stimulation of processes or soma although they are more sensitive to process deformation. There are at least two populations of MEN based on their sensitivity to different modalities of mechanical stress and on their firing pattern. (1) Rapidly, slowly and ultra-slowly adapting neurons which encode compressive forces. (2) Ultra-slowly adapting stretch-sensitive neurons encoding tensile forces. Rapid adaptation of firing is typically observed after compressive force while slow adaptation or ongoing spike discharge occurs often during tensile stress (stretch). All MEN have some common properties: they receive synaptic input, are low fidelity mechanoreceptors and are multifunctional in that some serve interneuronal others even motor functions. Consequently, MEN possess processes with mechanosensitive as well as efferent functions. This raises the intriguing hypothesis that MEN sense and control muscle activity at the same time as servo-feedback loop. The mechanosensitive channel(s) or receptor(s) expressed by the different MEN populations are unknown. Future concepts have to incorporate compressive and tensile-sensitive MEN into neural circuits that controls muscle activity. They may interact to control various forms of a particular motor pattern or regulate different motor patterns independently from each other. PMID:26528136

  4. Radiation response of the central nervous system

    SciTech Connect

    Schultheiss, T.E.; Kun, L.E.; Stephens, L.C.

    1995-03-30

    This report reviews the anatomical, pathophysiological, and clinical aspects of radiation injury to the central nervous system (CNS). Despite the lack of pathoGyomonic characteristics for CNS radiation lesions, demyelination and malacia are consistently the dominant morphological features of radiation myelopathy. In addition, cerebral atrophy is commonly observed in patients with neurological deficits related to chemotherapy and radiation, and neurocognitive deficits are associated with diffuse white matter changes. Clinical and experimental dose-response information have been evaluated and summarized into specific recommendations for the spinal cord and brain. The common spinal cord dose limit of 45 Gn in 22 to 25 fractions is conservative and can be relaxed if respecting this limit materially reduces the probability of tumor control. It is suggested that the 5% incidence of radiation myelopathy probably lies between 57 and 61 Gy to the spinal cord in the absence of dose modifying chemotherapy. A clinically detectable length effect for the spinal cord has not been observed. The effects of chemotherapy and altered fractionation are also discussed. Brain necrosis in adults is rarely noted below 60 Gy in conventional fractionation, with imaging and clinical changes being observed generally only above 50 Gy. However, neurocognitive effects are observed at lower doses, especially in children. A more pronounced volume effect is believed to exist in the brain than in the spinal cord. Tumor progression may be hard to distinguish from radiation and chemotherapy effects. Diffuse white matter injury can be attributed to radiation and associated with neurological deficits, but leukoencephalopathy is rarely observed in the absence of chemotherapy. Subjective, objective, management, and analytic (SOMA) parameters related to radiation spinal cord and brain injury have been developed and presented on ordinal scales. 140 refs., 3 figs., 6 tabs.

  5. Is There Anything "Autonomous" in the Nervous System?

    ERIC Educational Resources Information Center

    Rasia-Filho, Alberto A.

    2006-01-01

    The terms "autonomous" or "vegetative" are currently used to identify one part of the nervous system composed of sympathetic, parasympathetic, and gastrointestinal divisions. However, the concepts that are under the literal meaning of these words can lead to misconceptions about the actual nervous organization. Some clear-cut examples indicate…

  6. Evolution of the CNS myelin gene regulatory program.

    PubMed

    Li, Huiliang; Richardson, William D

    2016-06-15

    Myelin is a specialized subcellular structure that evolved uniquely in vertebrates. A myelinated axon conducts action potentials many times faster than an unmyelinated axon of the same diameter; for the same conduction speed, the unmyelinated axon would need a much larger diameter and volume than its myelinated counterpart. Hence myelin speeds information transfer and saves space, allowing the evolution of a powerful yet portable brain. Myelination in the central nervous system (CNS) is controlled by a gene regulatory program that features a number of master transcriptional regulators including Olig1, Olig2 and Myrf. Olig family genes evolved from a single ancestral gene in non-chordates. Olig2, which executes multiple functions with regard to oligodendrocyte identity and development in vertebrates, might have evolved functional versatility through post-translational modification, especially phosphorylation, as illustrated by its evolutionarily conserved serine/threonine phospho-acceptor sites and its accumulation of serine residues during more recent stages of vertebrate evolution. Olig1, derived from a duplicated copy of Olig2 in early bony fish, is involved in oligodendrocyte development and is critical to remyelination in bony vertebrates, but is lost in birds. The origin of Myrf orthologs might be the result of DNA integration between an invading phage or bacterium and an early protist, producing a fusion protein capable of self-cleavage and DNA binding. Myrf seems to have adopted new functions in early vertebrates - initiation of the CNS myelination program as well as the maintenance of mature oligodendrocyte identity and myelin structure - by developing new ways to interact with DNA motifs specific to myelin genes. This article is part of a Special Issue entitled SI: Myelin Evolution. PMID:26474911

  7. Robust axonal regeneration occurs in the injured CAST/Ei mouse central nervous system

    PubMed Central

    Omura, Takao; Omura, Kumiko; Tedeschi, Andrea; Riva, Priscilla; Painter, Michio W; Rojas, Leticia; Martin, Joshua; Lisi, Véronique; Huebner, Eric A; Latremoliere, Alban; Yin, Yuqin; Barrett, Lee; Singh, Bhagat; Lee, Stella; Crisman, Tom; Gao, Fuying; Li, Songlin; Kapur, Kush; Geschwind, Daniel H; Kosik, Kenneth S; Coppola, Giovanni; He, Zhigang; Carmichael, S Thomas; Benowitz, Larry I; Costigan, Michael; Woolf, Clifford J

    2015-01-01

    SUMMARY Axon regeneration in the central nervous system (CNS) requires reactivating injured neurons’ intrinsic growth state and enabling growth in an inhibitory environment. Using an inbred mouse neuronal phenotypic screen, we find that CAST/Ei mouse adult dorsal root ganglion neurons extend axons more on CNS myelin than the other eight strains tested, especially when pre-injured. Injury-primed CAST/Ei neurons also regenerate markedly in the spinal cord and optic nerve more than those from C57BL/6 mice and show greater spouting following ischemic stroke. Heritability estimates indicate that extended growth in CAST/Ei neurons on myelin is genetically determined, and two whole-genome expression screens yield the Activin transcript Inhba as most correlated with this ability. Inhibition of Activin signaling in CAST/Ei mice diminishes their CNS regenerative capacity whereas its activation in C57BL/6 animals boosts regeneration. This screen demonstrates that mammalian CNS regeneration can occur and reveals a molecular pathway that contributes to this ability. PMID:26004914

  8. BMP7 retards peripheral myelination by activating p38 MAPK in Schwann cells

    PubMed Central

    Liu, Xiaoyu; Zhao, Yahong; Peng, Su; Zhang, Shuqiang; Wang, Meihong; Chen, Yeyue; Zhang, Shan; Yang, Yumin; Sun, Cheng

    2016-01-01

    Schwann cell (SC) myelination is pivotal for the proper physiological functioning of the nervous system, but the underlying molecular mechanism remains less well understood. Here, we showed that the expression of bone morphogenetic protein 7 (BMP7) inversely correlates with myelin gene expression during peripheral myelination, which suggests that BMP7 is likely a negative regulator for myelin gene expression. Our experiments further showed that the application of BMP7 attenuates the cAMP induced myelin gene expression in SCs. Downstream pathway analysis suggested that both p38 MAPK and SMAD are activated by exogenous BMP7 in SCs. The pharmacological intervention and gene silence studies revealed that p38 MAPK, not SMAD, is responsible for BMP7-mediated suppression of myelin gene expression. In addition, c-Jun, a potential negative regulator for peripheral myelination, was up-regulated by BMP7. In vivo experiments showed that BMP7 treatment greatly impaired peripheral myelination in newborn rats. Together, our results established that BMP7 is a negative regulator for peripheral myelin gene expression and that p38 MAPK/c-Jun axis might be the main downstream target of BMP7 in this process. PMID:27491681

  9. A genetic screen identifies genes essential for development of myelinated axons in zebrafish.

    PubMed

    Pogoda, Hans-Martin; Sternheim, Nitzan; Lyons, David A; Diamond, Brianne; Hawkins, Thomas A; Woods, Ian G; Bhatt, Dimple H; Franzini-Armstrong, Clara; Dominguez, Claudia; Arana, Naomi; Jacobs, Jennifer; Nix, Rebecca; Fetcho, Joseph R; Talbot, William S

    2006-10-01

    The myelin sheath insulates axons in the vertebrate nervous system, allowing rapid propagation of action potentials via saltatory conduction. Specialized glial cells, termed Schwann cells in the PNS and oligodendrocytes in the CNS, wrap axons to form myelin, a compacted, multilayered sheath comprising specific proteins and lipids. Disruption of myelinated axons causes human diseases, including multiple sclerosis and Charcot-Marie-Tooth peripheral neuropathies. Despite the progress in identifying human disease genes and other mutations disrupting glial development and myelination, many important unanswered questions remain about the mechanisms that coordinate the development of myelinated axons. To address these questions, we began a genetic dissection of myelination in zebrafish. Here we report a genetic screen that identified 13 mutations, which define 10 genes, disrupting the development of myelinated axons. We present the initial characterization of seven of these mutations, defining six different genes, along with additional characterization of mutations that we have described previously. The different mutations affect the PNS, the CNS, or both, and phenotypic analyses indicate that the genes affect a wide range of steps in glial development, from fate specification through terminal differentiation. The analysis of these mutations will advance our understanding of myelination, and the mutants will serve as models of human diseases of myelin. PMID:16875686

  10. Arf6 guanine-nucleotide exchange factor cytohesin-2 regulates myelination in nerves.

    PubMed

    Torii, Tomohiro; Ohno, Nobuhiko; Miyamoto, Yuki; Kawahara, Kazuko; Saitoh, Yurika; Nakamura, Kazuaki; Takashima, Shou; Sakagami, Hiroyuki; Tanoue, Akito; Yamauchi, Junji

    2015-05-01

    In postnatal development of the peripheral nervous system (PNS), Schwann cells differentiate to insulate neuronal axons with myelin sheaths, increasing the nerve conduction velocity. To produce the mature myelin sheath with its multiple layers, Schwann cells undergo dynamic morphological changes. While extracellular molecules such as growth factors and cell adhesion ligands are known to regulate the myelination process, the intracellular molecular mechanism underlying myelination remains unclear. In this study, we have produced Schwann cell-specific conditional knockout mice for cytohesin-2, a guanine-nucleotide exchange factor (GEF) specifically activating Arf6. Arf6, a member of the Ras-like protein family, participates in various cellular functions including cell morphological changes. Cytohesin-2 knockout mice exhibit decreased Arf6 activity and reduced myelin thickness in the sciatic nerves, with decreased expression levels of myelin protein zero (MPZ), the major myelin marker protein. These results are consistent with those of experiments in which Schwann cell-neuronal cultures were treated with pan-cytohesin inhibitor SecinH3. On the other hand, the numbers of Ki67-positive cells in knockout mice and controls are comparable, indicating that cytohesin-2 does not have a positive effect on cell numbers. Thus, signaling through cytohesin-2 is required for myelination by Schwann cells, and cytohesin-2 is added to the list of molecules known to underlie PNS myelination. PMID:25824033

  11. BMP7 retards peripheral myelination by activating p38 MAPK in Schwann cells.

    PubMed

    Liu, Xiaoyu; Zhao, Yahong; Peng, Su; Zhang, Shuqiang; Wang, Meihong; Chen, Yeyue; Zhang, Shan; Yang, Yumin; Sun, Cheng

    2016-01-01

    Schwann cell (SC) myelination is pivotal for the proper physiological functioning of the nervous system, but the underlying molecular mechanism remains less well understood. Here, we showed that the expression of bone morphogenetic protein 7 (BMP7) inversely correlates with myelin gene expression during peripheral myelination, which suggests that BMP7 is likely a negative regulator for myelin gene expression. Our experiments further showed that the application of BMP7 attenuates the cAMP induced myelin gene expression in SCs. Downstream pathway analysis suggested that both p38 MAPK and SMAD are activated by exogenous BMP7 in SCs. The pharmacological intervention and gene silence studies revealed that p38 MAPK, not SMAD, is responsible for BMP7-mediated suppression of myelin gene expression. In addition, c-Jun, a potential negative regulator for peripheral myelination, was up-regulated by BMP7. In vivo experiments showed that BMP7 treatment greatly impaired peripheral myelination in newborn rats. Together, our results established that BMP7 is a negative regulator for peripheral myelin gene expression and that p38 MAPK/c-Jun axis might be the main downstream target of BMP7 in this process. PMID:27491681

  12. General Information about Childhood Central Nervous System Embryonal Tumors

    MedlinePlus

    ... System Embryonal Tumors Treatment (PDQ®)–Patient Version General Information About Childhood Central Nervous System Embryonal Tumors Go ... in patients with a high-risk tumor. The information from tests and procedures done to detect (find) ...

  13. Animal-microbe interactions and the evolution of nervous systems.

    PubMed

    Eisthen, Heather L; Theis, Kevin R

    2016-01-01

    Animals ubiquitously interact with environmental and symbiotic microbes, and the effects of these interactions on animal physiology are currently the subject of intense interest. Nevertheless, the influence of microbes on nervous system evolution has been largely ignored. We illustrate here how taking microbes into account might enrich our ideas about the evolution of nervous systems. For example, microbes are involved in animals' communicative, defensive, predatory and dispersal behaviours, and have likely influenced the evolution of chemo- and photosensory systems. In addition, we speculate that the need to regulate interactions with microbes at the epithelial surface may have contributed to the evolutionary internalization of the nervous system. PMID:26598731

  14. NMDA receptors mediate calcium accumulation in myelin during chemical ischaemia.

    PubMed

    Micu, I; Jiang, Q; Coderre, E; Ridsdale, A; Zhang, L; Woulfe, J; Yin, X; Trapp, B D; McRory, J E; Rehak, R; Zamponi, G W; Wang, W; Stys, P K

    2006-02-23

    Central nervous system myelin is a specialized structure produced by oligodendrocytes that ensheaths axons, allowing rapid and efficient saltatory conduction of action potentials. Many disorders promote damage to and eventual loss of the myelin sheath, which often results in significant neurological morbidity. However, little is known about the fundamental mechanisms that initiate myelin damage, with the assumption being that its fate follows that of the parent oligodendrocyte. Here we show that NMDA (N-methyl-d-aspartate) glutamate receptors mediate Ca2+ accumulation in central myelin in response to chemical ischaemia in vitro. Using two-photon microscopy, we imaged fluorescence of the Ca2+ indicator X-rhod-1 loaded into oligodendrocytes and the cytoplasmic compartment of the myelin sheath in adult rat optic nerves. The AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)/kainate receptor antagonist NBQX completely blocked the ischaemic Ca2+ increase in oligodendroglial cell bodies, but only modestly reduced the Ca2+ increase in myelin. In contrast, the Ca2+ increase in myelin was abolished by broad-spectrum NMDA receptor antagonists (MK-801, 7-chlorokynurenic acid, d-AP5), but not by more selective blockers of NR2A and NR2B subunit-containing receptors (NVP-AAM077 and ifenprodil). In vitro ischaemia causes ultrastructural damage to both axon cylinders and myelin. NMDA receptor antagonism greatly reduced the damage to myelin. NR1, NR2 and NR3 subunits were detected in myelin by immunohistochemistry and immunoprecipitation, indicating that all necessary subunits are present for the formation of functional NMDA receptors. Our data show that the mature myelin sheath can respond independently to injurious stimuli. Given that axons are known to release glutamate, our finding that the Ca2+ increase was mediated in large part by activation of myelinic NMDA receptors suggests a new mechanism of axo-myelinic signalling. Such a mechanism may represent a

  15. The Human Sympathetic Nervous System Response to Spaceflight

    NASA Technical Reports Server (NTRS)

    Ertl, Andrew C.; Diedrich, Andre; Paranjape, Sachin Y.; Biaggioni, Italo; Robertson, Rose Marie; Lane, Lynda D.; Shiavi, Richard; Robertson, David

    2003-01-01

    The sympathetic nervous system is an important part of the autonomic (or automatic) nervous system. When an individual stands up, the sympathetic nervous system speeds the heart and constricts blood vessels to prevent a drop in blood pressure. A significant number of astronauts experience a drop in blood pressure when standing for prolonged periods after they return from spaceflight. Difficulty maintaining blood pressure with standing is also a daily problem for many patients. Indirect evidence available before the Neurolab mission suggested the problem in astronauts while in space might be due partially to reduced sympathetic nervous system activity. The purpose of this experiment was to identify whether sympathetic activity was reduced during spaceflight. Sympathetic nervous system activity can be determined in part by measuring heart rate, nerve activity going to blood vessels, and the release of the hormone norepinephrine into the blood. Norepinephrine is a neurotransmitter discharged from active sympathetic nerve terminals, so its rate of release can serve as a marker of sympathetic nervous system action. In addition to standard cardiovascular measurements (heart rate, blood pressure), we determined sympathetic nerve activity as well as norepinephrine release and clearance on four crewmembers on the Neurolab mission. Contrary to our expectation, the results demonstrated that the astronauts had mildly elevated resting sympathetic nervous system activity in space. Sympathetic nervous system responses to stresses that simulated the cardiovascular effects of standing (lower body negative pressure) were brisk both during and after spaceflight. We concluded that, in the astronauts tested, the activity and response of the sympathetic nervous system to cardiovascular stresses appeared intact and mildly elevated both during and after spaceflight. These changes returned to normal within a few days.

  16. Evolution of eumetazoan nervous systems: insights from cnidarians

    PubMed Central

    Kelava, Iva; Rentzsch, Fabian; Technau, Ulrich

    2015-01-01

    Cnidarians, the sister group to bilaterians, have a simple diffuse nervous system. This morphological simplicity and their phylogenetic position make them a crucial group in the study of the evolution of the nervous system. The development of their nervous systems is of particular interest, as by uncovering the genetic programme that underlies it, and comparing it with the bilaterian developmental programme, it is possible to make assumptions about the genes and processes involved in the development of ancestral nervous systems. Recent advances in sequencing methods, genetic interference techniques and transgenic technology have enabled us to get a first glimpse into the molecular network underlying the development of a cnidarian nervous system—in particular the nervous system of the anthozoan Nematostella vectensis. It appears that much of the genetic network of the nervous system development is partly conserved between cnidarians and bilaterians, with Wnt and bone morphogenetic protein (BMP) signalling, and Sox genes playing a crucial part in the differentiation of neurons. However, cnidarians possess some specific characteristics, and further studies are necessary to elucidate the full regulatory network. The work on cnidarian neurogenesis further accentuates the need to study non-model organisms in order to gain insights into processes that shaped present-day lineages during the course of evolution. PMID:26554048

  17. Oligodendrocyte, Astrocyte, and Microglia Crosstalk in Myelin Development, Damage, and Repair.

    PubMed

    Domingues, Helena S; Portugal, Camila C; Socodato, Renato; Relvas, João B

    2016-01-01

    Oligodendrocytes are the myelinating glia of the central nervous system. Myelination of axons allows rapid saltatory conduction of nerve impulses and contributes to axonal integrity. Devastating neurological deficits caused by demyelinating diseases, such as multiple sclerosis, illustrate well the importance of the process. In this review, we focus on the positive and negative interactions between oligodendrocytes, astrocytes, and microglia during developmental myelination and remyelination. Even though many lines of evidence support a crucial role for glia crosstalk during these processes, the nature of such interactions is often neglected when designing therapeutics for repair of demyelinated lesions. Understanding the cellular and molecular mechanisms underlying glial cell communication and how they influence oligodendrocyte differentiation and myelination is fundamental to uncover novel therapeutic strategies for myelin repair. PMID:27551677

  18. Oligodendrocyte, Astrocyte, and Microglia Crosstalk in Myelin Development, Damage, and Repair

    PubMed Central

    Domingues, Helena S.; Portugal, Camila C.; Socodato, Renato; Relvas, João B.

    2016-01-01

    Oligodendrocytes are the myelinating glia of the central nervous system. Myelination of axons allows rapid saltatory conduction of nerve impulses and contributes to axonal integrity. Devastating neurological deficits caused by demyelinating diseases, such as multiple sclerosis, illustrate well the importance of the process. In this review, we focus on the positive and negative interactions between oligodendrocytes, astrocytes, and microglia during developmental myelination and remyelination. Even though many lines of evidence support a crucial role for glia crosstalk during these processes, the nature of such interactions is often neglected when designing therapeutics for repair of demyelinated lesions. Understanding the cellular and molecular mechanisms underlying glial cell communication and how they influence oligodendrocyte differentiation and myelination is fundamental to uncover novel therapeutic strategies for myelin repair. PMID:27551677

  19. Strategies for Enhanced Drug Delivery to the Central Nervous System

    PubMed Central

    Dwibhashyam, V. S. N. M.; Nagappa, A. N.

    2008-01-01

    Treating central nervous system diseases is very challenging because of the presence of a variety of formidable obstacles that impede drug delivery. Physiological barriers like the blood-brain barrier and blood-cerebrospinal fluid barrier as well as various efflux transporter proteins make the entry of drugs into the central nervous system very difficult. The present review provides a brief account of the blood brain barrier, the P-glycoprotein efflux and various strategies for enhancing drug delivery to the central nervous system. PMID:20046703

  20. Cryptococcosis of the central nervous system

    PubMed Central

    Edwards, V. E.; Sutherland, J. M.; Tyrer, J. H.

    1970-01-01

    (1) A survey of cryptococcal infections of the nervous system in Queensland, Australia, revealed the nine year prevalence rate for the Australian aboriginal to be some 17 times greater than that of the white population. Uncommon in the first decade of life, the disease was developed by 79% of 29 patients between 20 and 59 years, males being affected twice as commonly as females. (2) Cryptococcosis appears to be more common in Australia than in the United Kingdom, and in Queensland the nine year incidence of neurological cryptococcosis was 4·7 per 100,000 in the tropical north compared with 1·8 per 100,000 in the southern parts of the State. Because of this, and since 20 of the 29 patients were regarded as having outdoor occupations, it is suggested that a high environmental exposure to the fungus may be associated with an animal reservoir and with dry, dusty conditions. It is also possible that geographical and occupational factors rather than racial predisposition account for the high incidence of the disease in the Australian aborigine. However, individual resistance and susceptibility are probably also important factors, since the clinical disease appears to be positively correlated with certain other diseases, or with steroid therapy, which would impair the immune responses of the body. (3) Headache is the outstanding symptom of neurological cryptococcosis and fever or evidence of meningeal reaction, though often present, may be absent. An awareness of the possibility of neurological cryptococcosis in the differential diagnosis of various intracranial disorders should lead to identification of the encapsulated C. neoformans in the cerebrospinal fluid. Although in eight of 26 patients the lumbar cerebrospinal fluid was sterile on repeated examination, in five cases C. neoformans was found on direct examination of cerebrospinal fluid obtained by ventricular puncture. The remaining three died before further investigations could be performed. (4) Before the

  1. Myelin Recovery in Multiple Sclerosis: The Challenge of Remyelination

    PubMed Central

    Podbielska, Maria; Banik, Naren L.; Kurowska, Ewa; Hogan, Edward L.

    2013-01-01

    Multiple sclerosis (MS) is the most common demyelinating and an autoimmune disease of the central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. T cell subsets (Th1, Th2, Th17, CD8+, NKT, CD4+CD25+ T regulatory cells) and B cells are involved in this disorder, thus new MS therapies seek damage prevention by resetting multiple components of the immune system. The currently approved therapies are immunoregulatory and reduce the number and rate of lesion formation but are only partially effective. This review summarizes current understanding of the processes at issue: myelination, demyelination and remyelination—with emphasis upon myelin composition/architecture and oligodendrocyte maturation and differentiation. The translational options target oligodendrocyte protection and myelin repair in animal models and assess their relevance in human. Remyelination may be enhanced by signals that promote myelin formation and repair. The crucial question of why remyelination fails is approached is several ways by examining the role in remyelination of available MS medications and avenues being actively pursued to promote remyelination including: (i) cytokine-based immune-intervention (targeting calpain inhibition), (ii) antigen-based immunomodulation (targeting glycolipid-reactive iNKT cells and sphingoid mediated inflammation) and (iii) recombinant monoclonal antibodies-induced remyelination. PMID:24961530

  2. High-resolution structural model of porcine P2 myelin membrane protein with associated fatty acid ligand: fact or artifact?

    PubMed

    Sedzik, Jan; Jastrzebski, Jan Pawel

    2011-06-01

    Myelin membrane is a biological complex of glial cells origin; it is composed of 25% (w/w) proteins and 75% lipids, and more than 300 proteins are associated with central nervous system myelin (for peripheral nervous system myelin, such data are lacking). Myelin plays an important role in maintaining propagation of nerve signals. To uncover the nature of propagation phenomena, it is essential to study biochemistry of myelin proteins and lipids, myelin composition, and myelin structure. Nearly all myelin proteins are like antigens, causing clinically well-defined devastating diseases; multiple sclerosis and Guillain-Barré syndrome are two of them. In this article, a high-resolution study (1.8 Å) of porcine myelin P2 protein is presented. Myelin was purified from porcine intradural spinal roots, which were stored at -80°C for 10 years before myelin and P2 protein were purified (spinal roots were a gift of Prof. Kunio Kitamura, Saitama Medical School). The three-dimensional structural analysis uncovered embedded 18-carbons-long fatty acid. Some speculative interpretation is presented, to uncover how this ligand of fatty acid may form cholesterol ester and stabilize the myelin structure or form simple raft microdomain. Protein crystallography indicates that the ligand may be 18-carbons-long fatty acid. This is unlike previous work with mass spectrometry, in which three ligands were determined. In other protein crystallography-based studies of P2 (bovine), an oleic fatty acid was suggested, but, for recombinant (human) protein, palmitic acid was found. There is no fatty acid ligand in equine P2 protein. PMID:21425316

  3. The eye and visual nervous system: anatomy, physiology and toxicology.

    PubMed Central

    McCaa, C S

    1982-01-01

    The eyes are at risk to environmental injury by direct exposure to airborne pollutants, to splash injury from chemicals and to exposure via the circulatory system to numerous drugs and bloodborne toxins. In addition, drugs or toxins can destroy vision by damaging the visual nervous system. This review describes the anatomy and physiology of the eye and visual nervous system and includes a discussion of some of the more common toxins affecting vision in man. Images FIGURE 1. FIGURE 2. PMID:7084144

  4. Individual Neuronal Subtypes Exhibit Diversity in CNS Myelination Mediated by Synaptic Vesicle Release.

    PubMed

    Koudelka, Sigrid; Voas, Matthew G; Almeida, Rafael G; Baraban, Marion; Soetaert, Jan; Meyer, Martin P; Talbot, William S; Lyons, David A

    2016-06-01

    Regulation of myelination by oligodendrocytes in the CNS has important consequences for higher-order nervous system function (e.g., [1-4]), and there is growing consensus that neuronal activity regulates CNS myelination (e.g., [5-9]) through local axon-oligodendrocyte synaptic-vesicle-release-mediated signaling [10-12]. Recent analyses have indicated that myelination along axons of distinct neuronal subtypes can differ [13, 14], but it is not known whether regulation of myelination by activity is common to all neuronal subtypes or only some. This limits insight into how specific neurons regulate their own conduction. Here, we use a novel fluorescent fusion protein reporter to study myelination along the axons of distinct neuronal subtypes over time in zebrafish. We find that the axons of reticulospinal and commissural primary ascending (CoPA) neurons are among the first myelinated in the zebrafish CNS. To investigate how activity regulates myelination by different neuronal subtypes, we express tetanus toxin (TeNT) in individual reticulospinal or CoPA neurons to prevent synaptic vesicle release. We find that the axons of individual tetanus toxin expressing reticulospinal neurons have fewer myelin sheaths than controls and that their myelin sheaths are 50% shorter than controls. In stark contrast, myelination along tetanus-toxin-expressing CoPA neuron axons is entirely normal. These results indicate that while some neuronal subtypes modulate myelination by synaptic vesicle release to a striking degree in vivo, others do not. These data have implications for our understanding of how different neurons regulate myelination and thus their own function within specific neuronal circuits. PMID:27161502

  5. The evolution of vertebrate and invertebrate myelin: a theoretical computational study.

    PubMed

    Castelfranco, Ann M; Hartline, Daniel K

    2015-06-01

    Multilayered, lipid-rich myelin increases nerve impulse conduction velocity, contributes to compact nervous systems, and reduces metabolic costs of neural activity. Based on the hypothesis that increased impulse conduction velocity provides a selective advantage that drives the evolution of myelin, we simulated a sequence of plausible intermediate stages of myelin evolution, each of which providing an enhancement of conduction speed. We started with the expansion of insulating glial coverage, which led first to a single layer of myelin surrounding the axon and then to multiple myelin wraps with well-organized nodes. The myelinated fiber was modeled at three levels of complexity as the hypothesized evolutionary progression became more quantitatively exacting: 1) representing the fiber as a mathematically-tractable uniform active cylinder with the effect of myelination approximated by changing its specific capacitance (C(m)); 2) representing it as a chain of simple, cable-model compartments having alternating nodal and internodal parameters subject to optimization, and 3) representing it in a double cable model with the axon and myelin sheath treated separately. Conduction velocity was optimized at each stage. To maintain optimal conduction velocities, increased myelin coverage of axonal surface must be accompanied by an increase in channel density at the evolving nodes, but along with increases in myelin thickness, a reduction in overall average channel density must occur. Leakage under the myelin sheath becomes more of a problem with smaller fiber diameters, which may help explain the tendency for myelin to occur preferentially in larger nerve fibers in both vertebrates and invertebrates. PMID:25832903

  6. Kif13b Regulates PNS and CNS Myelination through the Dlg1 Scaffold

    PubMed Central

    Noseda, Roberta; Guerrero-Valero, Marta; Alberizzi, Valeria; Previtali, Stefano C.; Sherman, Diane L.; Palmisano, Marilena; Huganir, Richard L.; Nave, Klaus-Armin; Cuenda, Ana; Feltri, Maria Laura; Brophy, Peter J.; Bolino, Alessandra

    2016-01-01

    Microtubule-based kinesin motors have many cellular functions, including the transport of a variety of cargos. However, unconventional roles have recently emerged, and kinesins have also been reported to act as scaffolding proteins and signaling molecules. In this work, we further extend the notion of unconventional functions for kinesin motor proteins, and we propose that Kif13b kinesin acts as a signaling molecule regulating peripheral nervous system (PNS) and central nervous system (CNS) myelination. In this process, positive and negative signals must be tightly coordinated in time and space to orchestrate myelin biogenesis. Here, we report that in Schwann cells Kif13b positively regulates myelination by promoting p38γ mitogen-activated protein kinase (MAPK)-mediated phosphorylation and ubiquitination of Discs large 1 (Dlg1), a known brake on myelination, which downregulates the phosphatidylinositol 3-kinase (PI3K)/v-AKT murine thymoma viral oncogene homolog (AKT) pathway. Interestingly, Kif13b also negatively regulates Dlg1 stability in oligodendrocytes, in which Dlg1, in contrast to Schwann cells, enhances AKT activation and promotes myelination. Thus, our data indicate that Kif13b is a negative regulator of CNS myelination. In summary, we propose a novel function for the Kif13b kinesin in glial cells as a key component of the PI3K/AKT signaling pathway, which controls myelination in both PNS and CNS. PMID:27070899

  7. Kif13b Regulates PNS and CNS Myelination through the Dlg1 Scaffold.

    PubMed

    Noseda, Roberta; Guerrero-Valero, Marta; Alberizzi, Valeria; Previtali, Stefano C; Sherman, Diane L; Palmisano, Marilena; Huganir, Richard L; Nave, Klaus-Armin; Cuenda, Ana; Feltri, Maria Laura; Brophy, Peter J; Bolino, Alessandra

    2016-04-01

    Microtubule-based kinesin motors have many cellular functions, including the transport of a variety of cargos. However, unconventional roles have recently emerged, and kinesins have also been reported to act as scaffolding proteins and signaling molecules. In this work, we further extend the notion of unconventional functions for kinesin motor proteins, and we propose that Kif13b kinesin acts as a signaling molecule regulating peripheral nervous system (PNS) and central nervous system (CNS) myelination. In this process, positive and negative signals must be tightly coordinated in time and space to orchestrate myelin biogenesis. Here, we report that in Schwann cells Kif13b positively regulates myelination by promoting p38γ mitogen-activated protein kinase (MAPK)-mediated phosphorylation and ubiquitination of Discs large 1 (Dlg1), a known brake on myelination, which downregulates the phosphatidylinositol 3-kinase (PI3K)/v-AKT murine thymoma viral oncogene homolog (AKT) pathway. Interestingly, Kif13b also negatively regulates Dlg1 stability in oligodendrocytes, in which Dlg1, in contrast to Schwann cells, enhances AKT activation and promotes myelination. Thus, our data indicate that Kif13b is a negative regulator of CNS myelination. In summary, we propose a novel function for the Kif13b kinesin in glial cells as a key component of the PI3K/AKT signaling pathway, which controls myelination in both PNS and CNS. PMID:27070899

  8. Complex Homology and the Evolution of Nervous Systems

    PubMed Central

    Liebeskind, Benjamin J.; Hillis, David M.; Zakon, Harold H.; Hofmann, Hans A.

    2016-01-01

    We examine the complex evolution of animal nervous systems and discuss the ramifications of this complexity for inferring the nature of early animals. Although reconstructing the origins of nervous systems remains a central challenge in biology, and the phenotypic complexity of early animals remains controversial, a compelling picture is emerging. We now know that the nervous system and other key animal innovations contain a large degree of homoplasy, at least on the molecular level. Conflicting hypotheses about early nervous system evolution are due primarily to differences in the interpretation of this homoplasy. We highlight the need for explicit discussion of assumptions and discuss the limitations of current approaches for inferring ancient phenotypic states. PMID:26746806

  9. Improving and Accelerating Drug Development for Nervous System Disorders

    PubMed Central

    Pankevich, Diana E.; Altevogt, Bruce M.; Dunlop, John; Gage, Fred H.; Hyman, Steve E.

    2014-01-01

    Advances in the neurosciences have placed the field in the position where it is poised to significantly reduce the burden of nervous system disorders. However, drug discovery, development and translation for nervous system disorders still pose many unique challenges. The key scientific challenges can be summarized as follows: mechanisms of disease, target identification and validation, predictive models, biomarkers for patient stratification and as endpoints for clinical trials, clear regulatory pathways, reliability and reproducibility of published data, and data sharing and collaboration. To accelerate nervous system drug development the Institute of Medicine’s Forum on Neuroscience and Nervous System Disorders has hosted a series of public workshops that brought together representatives of industry, government (including both research funding and regulatory agencies), academia, and patient groups to discuss these challenges and offer potential strategies to improve the translational neuroscience. PMID:25442933

  10. Nervous system in the fibrillar theory of Giorgio Baglivi.

    PubMed

    Zurak, N

    2000-01-01

    The drafts, epistles, headwords, and conceptual basis known as the fibrillar theory of Giorgio Baglivi, published in his book entitled De fibra motrice et morbosa, were analyzed in an attempt to re-evaluate Baglivi's contribution, generally considered quite modest, to the development of scientific thought on the nervous system functions. The analysis revealed Baglivi's identification of the reflex organization, vegetative nervous system function, and neural aspect of the vasomotor function to be surprisingly valuable. I believe that the lucidity and genuine contemporariness of Baglivi's standpoints arise the question of the historical precedence in the discovery of these functions (it is usually attributed to F.X. Bichat for vegetative nervous system, and to Claude Bernard for vasomotor nerves). In the light of these facts, the need of an expert revision of the history of discovering nervous system functions is suggested. PMID:11624709