Key Specifications Table
|Species Reactivity||Key Applications||Host||Format||Antibody Type|
|H, M, R||IHC, IH(P), WB||Rb||Purified||Polyclonal Antibody|
|Presentation||Liquid in 0.05 mol/L Tris-HCl, pH 7.6 with 15 mmol/L sodium azide.|
|Safety Information according to GHS|
|Storage and Shipping Information|
|Storage Conditions||Stable for 1 year at 2-8ºC from date of receipt.|
|Material Size||500 µL|
References | 46 Available | See All References
|Reference overview||Application||Pub Med ID|
|The pre- and post-somatic segments of the human type I spiral ganglion neurons--structural and functional considerations related to cochlear implantation. |
Liu, W; Edin, F; Atturo, F; Rieger, G; Löwenheim, H; Senn, P; Blumer, M; Schrott-Fischer, A; Rask-Andersen, H; Glueckert, R
Neuroscience 284 470-82 2015
Human auditory nerve afferents consist of two separate systems; one is represented by the large type I cells innervating the inner hair cells and the other one by the small type II cells innervating the outer hair cells. Type I spiral ganglion neurons (SGNs) constitute 96% of the afferent nerve population and, in contrast to other mammals, their soma and pre- and post-somatic segments are unmyelinated. Type II nerve soma and fibers are unmyelinated. Histopathology and clinical experience imply that human SGNs can persist electrically excitable without dendrites, thus lacking connection to the organ of Corti. The biological background to this phenomenon remains elusive. We analyzed the pre- and post-somatic segments of the type I human SGNs using immunohistochemistry and transmission electron microscopy (TEM) in normal and pathological conditions. These segments were found surrounded by non-myelinated Schwann cells (NMSCs) showing strong intracellular expression of laminin-β2/collagen IV. These cells also bordered the perikaryal entry zone and disclosed surface rugosities outlined by a folded basement membrane (BM) expressing laminin-β2 and collagen IV. It is presumed that human large SGNs are demarcated by three cell categories: (a) myelinated Schwann cells, (b) NMSCs and (c) satellite glial cells (SGCs). Their BMs express laminin-β2/collagen IV and reaches the BM of the sensory epithelium at the habenula perforata. We speculate that the NMSCs protect SGNs from further degeneration following dendrite loss. It may give further explanation why SGNs can persist as electrically excitable monopolar cells even after long-time deafness, a blessing for the deaf treated with cochlear implantation.
|Olig1 function is required for oligodendrocyte differentiation in the mouse brain. |
Dai, J; Bercury, KK; Ahrendsen, JT; Macklin, WB
The Journal of neuroscience : the official journal of the Society for Neuroscience 35 4386-402 2015
Oligodendrocyte differentiation and myelination are tightly regulated processes orchestrated by a complex transcriptional network. Two bHLH transcription factors in this network, Olig1 and Olig2, are expressed exclusively by oligodendrocytes after late embryonic development. Although the role of Olig2 in the lineage is well established, the role of Olig1 is still unclear. The current studies analyzed the function of Olig1 in oligodendrocyte differentiation and developmental myelination in brain. Both oligodendrocyte progenitor cell commitment and oligodendrocyte differentiation were impaired in the corpus callosum of Olig1-null mice, resulting in hypomyelination throughout adulthood in the brain. As seen in previous studies with this mouse line, although there was an early myelination deficit in the spinal cord, essentially full recovery with normal spinal cord myelination was seen. Intriguingly, this regional difference may be partially attributed to compensatory upregulation of Olig2 protein expression in the spinal cord after Olig1 deletion, which is not seen in brain. The current study demonstrates a unique role for Olig1 in promoting oligodendrocyte progenitor cell commitment, differentiation, and subsequent myelination primarily in brain, but not spinal cord.
|The adhesion G protein-coupled receptor GPR56 is a cell-autonomous regulator of oligodendrocyte development. |
Giera, S; Deng, Y; Luo, R; Ackerman, SD; Mogha, A; Monk, KR; Ying, Y; Jeong, SJ; Makinodan, M; Bialas, AR; Chang, BS; Stevens, B; Corfas, G; Piao, X
Nature communications 6 6121 2015
Mutations in GPR56, a member of the adhesion G protein-coupled receptor family, cause a human brain malformation called bilateral frontoparietal polymicrogyria (BFPP). Magnetic resonance imaging (MRI) of BFPP brains reveals myelination defects in addition to brain malformation. However, the cellular role of GPR56 in oligodendrocyte development remains unknown. Here, we demonstrate that loss of Gpr56 leads to hypomyelination of the central nervous system in mice. GPR56 levels are abundant throughout early stages of oligodendrocyte development, but are downregulated in myelinating oligodendrocytes. Gpr56-knockout mice manifest with decreased oligodendrocyte precursor cell (OPC) proliferation and diminished levels of active RhoA, leading to fewer mature oligodendrocytes and a reduced number of myelinated axons in the corpus callosum and optic nerves. Conditional ablation of Gpr56 in OPCs leads to a reduced number of mature oligodendrocytes as seen in constitutive knockout of Gpr56. Together, our data define GPR56 as a cell-autonomous regulator of oligodendrocyte development.
|TREM2 sustains microglial expansion during aging and response to demyelination. |
Poliani, PL; Wang, Y; Fontana, E; Robinette, ML; Yamanishi, Y; Gilfillan, S; Colonna, M
The Journal of clinical investigation 125 2161-70 2015
Microglia contribute to development, homeostasis, and immunity of the CNS. Like other tissue-resident macrophage populations, microglia express the surface receptor triggering receptor expressed on myeloid cells 2 (TREM2), which binds polyanions, such as dextran sulphate and bacterial LPS, and activates downstream signaling cascades through the adapter DAP12. Individuals homozygous for inactivating mutations in TREM2 exhibit demyelination of subcortical white matter and a lethal early onset dementia known as Nasu-Hakola disease. How TREM2 deficiency mediates demyelination and disease is unknown. Here, we addressed the basis for this genetic association using Trem2(-/-) mice. In WT mice, microglia expanded in the corpus callosum with age, whereas aged Trem2(-/-) mice had fewer microglia with an abnormal morphology. In the cuprizone model of oligodendrocyte degeneration and demyelination, Trem2(-/-) microglia failed to amplify transcripts indicative of activation, phagocytosis, and lipid catabolism in response to myelin damage. As a result, Trem2(-/-) mice exhibited impaired myelin debris clearance, axonal dystrophy, oligodendrocyte reduction, and persistent demyelination after prolonged cuprizone treatment. Moreover, myelin-associated lipids robustly triggered TREM2 signaling in vitro, suggesting that TREM2 may directly sense lipid components exposed during myelin damage. We conclude that TREM2 is required for promoting microglial expansion during aging and microglial response to insults of the white matter.
|IKAP deficiency in an FD mouse model and in oligodendrocyte precursor cells results in downregulation of genes involved in oligodendrocyte differentiation and myelin formation. |
Cheishvili, D; Dietrich, P; Maayan, C; Even, A; Weil, M; Dragatsis, I; Razin, A
PloS one 9 e94612 2014
The splice site mutation in the IKBKAP gene coding for IKAP protein leads to the tissue-specific skipping of exon 20, with concomitant reduction in IKAP protein production. This causes the neurodevelopmental, autosomal-recessive genetic disorder - Familial Dysautonomia (FD). The molecular hallmark of FD is the severe reduction of IKAP protein in the nervous system that is believed to be the main reason for the devastating symptoms of this disease. Our recent studies showed that in the brain of two FD patients, genes linked to oligodendrocyte differentiation and/or myelin formation are significantly downregulated, implicating IKAP in the process of myelination. However, due to the scarcity of FD patient tissues, these results awaited further validation in other models. Recently, two FD mouse models that faithfully recapitulate FD were generated, with two types of mutations resulting in severely low levels of IKAP expression. Here we demonstrate that IKAP deficiency in these FD mouse models affects a similar set of genes as in FD patients' brains. In addition, we identified two new IKAP target genes involved in oligodendrocyte cells differentiation and myelination, further underscoring the essential role of IKAP in this process. We also provide proof that IKAP expression is needed cell-autonomously for the regulation of expression of genes involved in myelin formation since knockdown of IKAP in the Oli-neu oligodendrocyte precursor cell line results in similar deficiencies. Further analyses of these two experimental models will compensate for the lack of human postmortem tissues and will advance our understanding of the role of IKAP in myelination and the disease pathology.
|Adrenomedullin protects from experimental autoimmune encephalomyelitis at multiple levels. |
Pedreño, M; Morell, M; Robledo, G; Souza-Moreira, L; Forte-Lago, I; Caro, M; O'Valle, F; Ganea, D; Gonzalez-Rey, E
Brain, behavior, and immunity 37 152-63 2014
Adrenomedullin is a neuropeptide known for its cardiovascular activities and anti-inflammatory effects. Here, we investigated the effect of adrenomedullin in a model of experimental autoimmune encephalomyelitis (EAE) that mirrors chronic progressive multiple sclerosis. A short-term systemic treatment with adrenomedullin reduced clinical severity and incidence of EAE, the appearance of inflammatory infiltrates in spinal cord and the subsequent demyelination and axonal damage. This effect was exerted at multiple levels affecting both early and late events of the disease. Adrenomedullin decreased the presence/activation of encephalitogenic Th1 and Th17 cells and down-regulated several inflammatory mediators in peripheral lymphoid organs and central nervous system. Noteworthy, adrenomedullin inhibited the production by encephalitogenic cells of osteopontin and of Granulocyte Macrophage Colony-Stimulating Factor (GM-CSF), two critical cytokines in the development of EAE. At the same time, adrenomedullin increased the number of IL-10-producing regulatory T cells with suppressive effects on the progression of EAE. Furthermore, adrenomedullin generated dendritic cells with a semi-mature phenotype that impaired encephalitogenic responses in vitro and in vivo. Finally, adrenomedullin regulated glial activity and favored an active program of neuroprotection/regeneration. Therefore, the use of adrenomedullin emerges as a novel multimodal therapeutic approach to treat chronic progressive multiple sclerosis.
|Functionally distinct PI 3-kinase pathways regulate myelination in the peripheral nervous system. |
Heller, BA; Ghidinelli, M; Voelkl, J; Einheber, S; Smith, R; Grund, E; Morahan, G; Chandler, D; Kalaydjieva, L; Giancotti, F; King, RH; Fejes-Toth, AN; Fejes-Toth, G; Feltri, ML; Lang, F; Salzer, JL
The Journal of cell biology 204 1219-36 2014
The PI 3-kinase (PI 3-K) signaling pathway is essential for Schwann cell myelination. Here we have characterized PI 3-K effectors activated during myelination by probing myelinating cultures and developing nerves with an antibody that recognizes phosphorylated substrates for this pathway. We identified a discrete number of phospho-proteins including the S6 ribosomal protein (S6rp), which is down-regulated at the onset of myelination, and N-myc downstream-regulated gene-1 (NDRG1), which is up-regulated strikingly with myelination. We show that type III Neuregulin1 on the axon is the primary activator of S6rp, an effector of mTORC1. In contrast, laminin-2 in the extracellular matrix (ECM), signaling through the α6β4 integrin and Sgk1 (serum and glucocorticoid-induced kinase 1), drives phosphorylation of NDRG1 in the Cajal bands of the abaxonal compartment. Unexpectedly, mice deficient in α6β4 integrin signaling or Sgk1 exhibit hypermyelination during development. These results identify functionally and spatially distinct PI 3-K pathways: an early, pro-myelinating pathway driven by axonal Neuregulin1 and a later-acting, laminin-integrin-dependent pathway that negatively regulates myelination.
|Coxsackievirus B exits the host cell in shed microvesicles displaying autophagosomal markers. |
Robinson, SM; Tsueng, G; Sin, J; Mangale, V; Rahawi, S; McIntyre, LL; Williams, W; Kha, N; Cruz, C; Hancock, BM; Nguyen, DP; Sayen, MR; Hilton, BJ; Doran, KS; Segall, AM; Wolkowicz, R; Cornell, CT; Whitton, JL; Gottlieb, RA; Feuer, R
PLoS pathogens 10 e1004045 2014
Coxsackievirus B3 (CVB3), a member of the picornavirus family and enterovirus genus, causes viral myocarditis, aseptic meningitis, and pancreatitis in humans. We genetically engineered a unique molecular marker, "fluorescent timer" protein, within our infectious CVB3 clone and isolated a high-titer recombinant viral stock (Timer-CVB3) following transfection in HeLa cells. "Fluorescent timer" protein undergoes slow conversion of fluorescence from green to red over time, and Timer-CVB3 can be utilized to track virus infection and dissemination in real time. Upon infection with Timer-CVB3, HeLa cells, neural progenitor and stem cells (NPSCs), and C2C12 myoblast cells slowly changed fluorescence from green to red over 72 hours as determined by fluorescence microscopy or flow cytometric analysis. The conversion of "fluorescent timer" protein in HeLa cells infected with Timer-CVB3 could be interrupted by fixation, suggesting that the fluorophore was stabilized by formaldehyde cross-linking reactions. Induction of a type I interferon response or ribavirin treatment reduced the progression of cell-to-cell virus spread in HeLa cells or NPSCs infected with Timer-CVB3. Time lapse photography of partially differentiated NPSCs infected with Timer-CVB3 revealed substantial intracellular membrane remodeling and the assembly of discrete virus replication organelles which changed fluorescence color in an asynchronous fashion within the cell. "Fluorescent timer" protein colocalized closely with viral 3A protein within virus replication organelles. Intriguingly, infection of partially differentiated NPSCs or C2C12 myoblast cells induced the release of abundant extracellular microvesicles (EMVs) containing matured "fluorescent timer" protein and infectious virus representing a novel route of virus dissemination. CVB3 virions were readily observed within purified EMVs by transmission electron microscopy, and infectious virus was identified within low-density isopycnic iodixanol gradient fractions consistent with membrane association. The preferential detection of the lipidated form of LC3 protein (LC3 II) in released EMVs harboring infectious virus suggests that the autophagy pathway plays a crucial role in microvesicle shedding and virus release, similar to a process previously described as autophagosome-mediated exit without lysis (AWOL) observed during poliovirus replication. Through the use of this novel recombinant virus which provides more dynamic information from static fluorescent images, we hope to gain a better understanding of CVB3 tropism, intracellular membrane reorganization, and virus-associated microvesicle dissemination within the host.
|Effects of adult neural precursor-derived myelination on axonal function in the perinatal congenitally dysmyelinated brain: optimizing time of intervention, developing accurate prediction models, and enhancing performance. |
Ruff, CA; Ye, H; Legasto, JM; Stribbell, NA; Wang, J; Zhang, L; Fehlings, MG
The Journal of neuroscience : the official journal of the Society for Neuroscience 33 11899-915 2013
Stem cell repair shows substantial translational potential for neurological injury, but the mechanisms of action remain unclear. This study aimed to investigate whether transplanted stem cells could induce comprehensive functional remyelination. Subventricular zone (SVZ)-derived adult neural precursor cells (aNPCs) were injected bilaterally into major cerebral white matter tracts of myelin-deficient shiverer mice on postnatal day (P) 0, P7, and P21. Tripotential NPCs, when transplanted in vivo, integrated anatomically and functionally into local white matter and preferentially became Olig2+, Myelin Associated Glycoprotein-positive, Myelin Basic Protein-positive oligodendrocytes, rather than Glial Fibrillary Acidic Protein-positive astrocytes or Neurofiliment 200-positive neurons. Processes interacted with axons and transmission electron microscopy showed multilamellar axonal ensheathment. Nodal architecture was restored and by quantifying these anatomical parameters a computer model was generated that accurately predicted action potential velocity, determined by ex vivo slice recordings. Although there was no obvious phenotypic improvement in transplanted shi/shis, myelinated axons exhibited faster conduction, lower activation threshold, less refractoriness, and improved response to high-frequency stimulation than dysmyelinated counterparts. Furthermore, they showed improved resilience to ischemic insult, a promising finding in the context of perinatal brain injury. This study describes, for the first time mechanistically, the functional characteristics and anatomical integration of nonimmortalized donor SVZ-derived murine aNPCs in the dysmyelinated brain at key developmental time points.
|Immunophenotyping of inflammatory cells associated with Schmallenberg virus infection of the central nervous system of ruminants. |
Herder, V; Hansmann, F; Wohlsein, P; Peters, M; Varela, M; Palmarini, M; Baumgärtner, W
PloS one 8 e62939 2013
Schmallenberg virus (SBV) is a recently discovered Bunyavirus associated mainly with abortions, stillbirths and malformations of the skeletal and central nervous system (CNS) in newborn ruminants. In this study, a detailed immunophenotyping of the inflammatory cells of the CNS of affected animals was carried out in order to increase our understanding of SBV pathogenesis. A total of 82 SBV-polymerase chain reaction (PCR) positive neonatal ruminants (46 sheep lambs, 34 calves and 2 goat kids) were investigated for the presence of inflammation in the brain and spinal cord. The study focused on 15 out of 82 animals (18.3%) showing inflammation in the CNS. All 15 neonates displayed lymphohistiocytic meningoencephalomyelitis affecting most frequently the mesencephalon and the parietal and temporal lobes. The majority of infiltrating cells were CD3-positive T cells, followed by CD79α-positive B cells and CD68-positive microglia/macrophages. Malformations like por- and hydranencephaly, frequently found in the temporal lobe, showed associated demyelination and axonal loss. SBV antigen was detected in 37 out of 82 (45.1%) neonatal brains by immunohistochemistry. In particular, SBV antigen was found in 93.3% (14 out of 15 ruminants) and 32.8% (22 out of 67 ruminants) of animals with and without encephalitis, respectively. Highest amounts of virus-protein expression levels were found in the temporal lobe. Our findings suggest that: (i) different brain regions display differential susceptibility to SBV infection; (ii) inflammatory cells in the CNS are found only in a minority of virus infected animals; (iii) malformations occur in association with and without inflammation in the CNS; and (iv) viral antigen is strongly associated with the presence of inflammation in naturally infected animals. Further studies are required to explore the cell tropism and pathogenesis of SBV infection in ruminants.
|PDGF is required for remyelination-promoting IgM stimulation of oligodendrocyte progenitor cell proliferation. |
Watzlawik, JO; Warrington, AE; Rodriguez, M
PloS one 8 e55149 2013
Promotion of remyelination is a major goal in treating demyelinating diseases such as multiple sclerosis (MS). The recombinant human monoclonal IgM, rHIgM22, targets myelin and oligodendrocytes (OLs) and promotes remyelination in animal models of MS. It is unclear whether rHIgM22-mediated stimulation of lesion repair is due to promotion of oligodendrocyte progenitor cell (OPC) proliferation and survival, OPC differentiation into myelinating OLs or protection of mature OLs. It is also unknown whether astrocytes or microglia play a functional role in IgM-mediated lesion repair.We assessed the effect of rHIgM22 on cell proliferation in mixed CNS glial and OPC cultures by tritiated-thymidine uptake and by double-label immunocytochemistry using the proliferation marker, Ki-67. Antibody-mediated signaling events, OPC differentiation and OPC survival were investigated and quantified by Western blots.rHIgM22 stimulates OPC proliferation in mixed glial cultures but not in purified OPCs. There is no proliferative response in astrocytes or microglia. rHIgM22 activates PDGFαR in OPCs in mixed glial cultures. Blocking PDGFR-kinase inhibits rHIgM22-mediated OPC proliferation in mixed glia. We confirm in isolated OPCs that rHIgM22-mediated anti-apoptotic signaling and inhibition of OPC differentiation requires PDGF and FGF-2. We observed no IgM-mediated effect in mature OLs in the absence of PDGF and FGF-2.Stimulation of OPC proliferation by rHIgM22 depends on co-stimulatory astrocytic and/or microglial factors. We demonstrate that rHIgM22-mediated activation of PDGFαR is required for stimulation of OPC proliferation. We propose that rHIgM22 lowers the PDGF threshold required for OPC proliferation and protection, which can result in remyelination of CNS lesions.
|A possible role for inflammation in mediating apoptosis of oligodendrocytes as induced by the Lyme disease spirochete Borrelia burgdorferi. |
Geeta Ramesh,Shemi Benge,Bapi Pahar,Mario T Philipp
Journal of neuroinflammation 9 2012
|Axon myelination and electrical stimulation in a microfluidic, compartmentalized cell culture platform. |
In Hong Yang,Devin Gary,Misti Malone,Stephen Dria,Thierry Houdayer,Visar Belegu,John W McDonald,Nitish Thakor
Neuromolecular medicine 14 2012
Axon demyelination contributes to the loss of sensory and motor function following injury or disease in the central nervous system. Numerous reports have demonstrated that myelination can be achieved in neuron/oligodendrocyte co-cultures. However, the ability to selectively treat neuron or oligodendrocyte (OL) cell bodies in co-cultures improves the value of these systems when designing mechanism-based therapeutics. We have developed a microfluidic-based compartmentalized culture system to achieve segregation of neuron and OL cell bodies while simultaneously allowing the formation of myelin sheaths. Our microfluidic platform allows for a high replicate number, minimal leakage, and high flexibility. Using a custom built lid, fit with platinum electrodes for electrical stimulation (10-Hz pulses at a constant 3 V with ~190 kΩ impedance), we employed the microfluidic platform to achieve activity-dependent myelin segment formation. Electrical stimulation of dorsal root ganglia resulted in a fivefold increase in the number of myelinated segments/mm² when compared to unstimulated controls (19.6 ± 3.0 vs. 3.6 ± 2.3 MBP+ segments/mm²). This work describes the modification of a microfluidic, multi-chamber system so that electrical stimulation can be used to achieve increased levels of myelination while maintaining control of the cell culture microenvironment.
|Olig1 function is required for remyelination potential of transplanted neural progenitor cells in a model of viral-induced demyelination. |
Whitman, LM; Blanc, CA; Schaumburg, CS; Rowitch, DH; Lane, TE
Experimental neurology 235 380-7 2012
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) resulting in cumulative neurologic deficits associated with progressive myelin loss. We have previously shown that transplantation of neural progenitor cells (NPCs) into mice persistently infected with the JHM strain of mouse hepatitis virus (JHMV) results in enhanced differentiation into oligodendrocyte progenitor cells (OPCs) that is associated with remyelination and axonal sparing. The current study examines the contributions of the transcription factor Olig1 on NPC differentiation and remyelination. Under defined conditions, NPCs preferentially differentiate into oligodendroglia whereas NPCs isolated from Olig1-deficient (Olig1-/-) mice exhibit enhanced differentiation into astrocytes. Transplantation of Olig1-/- and Olig1+/+ NPCs into JHMV-infected mice resulted in similar cell survival, proliferation, and selective migration to areas of demyelination. However, only recipients of wild type NPCs exhibited extensive remyelination compared to mice receiving Olig1-/- NPCs. In vivo characterization of NPCs revealed that Olig1+/+ NPCs preferentially differentiated into NG2-positive OPCs and formed processes expressing myelin basic protein that encircled axons. In contrast, the majority of transplanted Olig1-/- NPCs differentiated into GFAP-positive cells consistent with the astrocyte lineage. These results indicate that exogenous NPCs contribute to improved clinical and histological outcome and this is associated with remyelination by this donor population. Further, these findings reveal that Olig1function is required for the remyelination potential of NPCs after transplant, through specification and/or maintenance of oligodendroglial identity.
|Coxsackievirus preferentially replicates and induces cytopathic effects in undifferentiated neural progenitor cells. |
Tsueng, G; Tabor-Godwin, JM; Gopal, A; Ruller, CM; Deline, S; An, N; Frausto, RF; Milner, R; Crocker, SJ; Whitton, JL; Feuer, R
Journal of virology 85 5718-32 2011
Enteroviruses, including coxsackieviruses, exhibit significant tropism for the central nervous system, and these viruses are commonly associated with viral meningitis and encephalitis. Previously, we described the ability of coxsackievirus B3 (CVB3) to infect proliferating neuronal progenitor cells located in the neonatal subventricular zone and persist in the adult murine central nervous system (CNS). Here, we demonstrate that cultured murine neurospheres, which comprise neural stem cells and their progeny at different stages of development, were highly susceptible to CVB3 infection. Neurospheres, or neural progenitor and stem cells (NPSCs), isolated from neonatal C57BL/6 mice, supported high levels of infectious virus production and high viral protein expression levels following infection with a recombinant CVB3 expressing enhanced green fluorescent protein (eGFP) protein. Similarly, NPSCs isolated from neonatal actin-promoter-GFP transgenic mice (actin-GFP NPSCs) were highly susceptible to infection with a recombinant CVB3 expressing DsRed (Discosoma sp. red fluorescent protein). Both nestin-positive and NG2(+) progenitor cells within neurospheres were shown to preferentially express high levels of viral protein as soon as 24 h postinfection (p.i.). By day 3 p.i., viral protein expression and viral titers increased dramatically in NPSCs with resultant cytopathic effects (CPE) and eventual cell death. In contrast, reduced viral replication, lower levels of CPE, and diminished viral protein expression levels were observed in NPSCs differentiated for 5 or 16 days in the presence of fetal bovine serum (FBS). Despite the presence of CPE and high levels of cell death following early CVB3 infection, surviving neurospheres were readily observed and continued to express detectable levels of viral protein as long as 37 days after initial infection. Also, CVB3 infection of actin-GFP NPSCs increased the percentage of cells expressing neuronal class III β-tubulin following their differentiation in the presence of FBS. These results suggest that neural stem cells may be preferentially targeted by CVB3 and that neurogenic regions of the CNS may support persistent viral replication in the surviving host. In addition, normal progenitor cell differentiation may be altered in the host following infection.
|Polystyrene replicas of neuronal basal lamina act as excellent guides for regenerating neurites. |
Karlsson M, Johansson F, Kanje M
Acta biomaterialia 2011
Various scaffolds, natural or artificial, have been used for neural repair, including basal lamina scaffolds obtained through extraction of nerves. Here we tested whether plastic casts of such preparations could be used for neurite guidance. To this end, longitudinal micron thick sections of rat sciatic nerve were extracted with detergents and treated with Dnase, yielding an acellular basal lamina master. From the basal lamina master a polydimethylsiloxane (PDMS) mold was made. Then a polystyrene replica was made using the PDMS mold as the master. The polystyrene replica showed high similarity to the master within nanometer resolution as revealed by scanning electron microscopy. Organ cultured mouse dorsal root ganglia grown on the polystyrene replica and the master preparation exhibited guided outgrowth of neurites as assayed by two-dimensional fast Fourier transform analysis on preparations, where the neurites had been visualized by β-III-tubulin staining. The neurites aligned longitudally in the direction of the original basal lamina tubes. Thus, using inexpensive methods it is possible to make replicas of basal lamina which can be used for neurite guidance. This opens a new avenue for nerve reconstruction.Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
|Gas6 increases myelination by oligodendrocytes and its deficiency delays recovery following cuprizone-induced demyelination. |
Binder, MD; Xiao, J; Kemper, D; Ma, GZ; Murray, SS; Kilpatrick, TJ
PloS one 6 e17727 2011
Multiple sclerosis (MS) is a complex demyelinating disease of the central nervous system. Current research has shown that at least in some cases, the primary insult in MS could be directed at the oligodendrocyte, and that the earliest immune responses are primarily via innate immune cells. We have identified a family of receptor protein tyrosine kinases, known as the TAM receptors (Tyro3, Axl and Mertk), as potentially important in regulating both the oligodendrocyte and immune responses. We have previously shown that Gas6, a ligand for the TAM receptors, can affect the severity of demyelination in mice, with a loss of signalling via Gas6 leading to decreased oligodendrocyte survival and increased microglial activation during cuprizone-induced demyelination. We hypothesised TAM receptor signalling would also influence the extent of recovery in mice following demyelination. A significant effect of the absence of Gas6 was detected upon remyelination, with a lower level of myelination after 4 weeks of recovery in comparison with wild-type mice. The delay in remyelination was accompanied by a reduction in oligodendrocyte numbers. To understand the molecular mechanisms that drive the observed effects, we also examined the effect of exogenous Gas6 in in vitro myelination assays. We found that Gas6 significantly increased myelination in a dose-dependent manner, suggesting that TAM receptor signalling could be directly involved in myelination by oligodendrocytes. The reduced rate of remyelination in the absence of Gas6 could thus result from a lack of Gas6 at a critical time during myelin production after injury. These findings establish Gas6 as an important regulator of both CNS demyelination and remyelination.Full Text Article
|Differentiation of induced pluripotent stem cells into functional oligodendrocytes. |
Czepiel M, Balasubramaniyan V, Schaafsma W, Stancic M, Mikkers H, Huisman C, Boddeke E, Copray S
Glia 59 882-92 2011
The technology to generate autologous pluripotent stem cells (iPS cells) from almost any somatic cell type has brought various cell replacement therapies within clinical research. Besides the challenge to optimize iPS protocols to appropriate safety and GMP levels, procedures need to be developed to differentiate iPS cells into specific fully differentiated and functional cell types for implantation purposes. In this article, we describe a protocol to differentiate mouse iPS cells into oligodendrocytes with the aim to investigate the feasibility of IPS stem cell-based therapy for demyelinating disorders, such as multiple sclerosis. Our protocol results in the generation of oligodendrocyte precursor cells (OPCs) that can develop into mature, myelinating oligodendrocytes in-vitro (co-culture with DRG neurons) as well as in-vivo (after implantation in the demyelinated corpus callosum of cuprizone-treated mice). We report the importance of complete purification of the iPS-derived OPC suspension to prevent the contamination with teratoma-forming iPS cells. © 2011 Wiley-Liss, Inc. Copyright © 2011 Wiley-Liss, Inc.
|Isolation and characterization of adult neural stem cells. |
Florian A Siebzehnrubl,Vinata Vedam-Mai,Hassan Azari,Brent A Reynolds,Loic P Deleyrolle
Methods in molecular biology (Clifton, N.J.) 750 2011
It has been thought for a long time that the adult brain is incapable of generating new neurons, or that neurons cannot be added to its complex circuitry. However, recent technology has resulted in an explosion of research demonstrating that neurogenesis, or the birth of new neurons from adult stem cells constitutively occurs in two specific regions of the mammalian brain; namely the subventricular zone and hippocampal dentate gyrus. Adult CNS stem cells exhibit three main characteristics: (1) they are self-renewing, i.e., they possess a theoretically unlimited ability to produce progeny indistinguishable from themselves, (2) they are proliferative (undergoing mitosis) and (3) they are multipotent for the different neuroectodermal lineages of the CNS, including the different neuronal, and glial subtypes. CNS stem cells and all progenitor cell types are broadly termed precursors. In this chapter, we describe methods to identify, isolate and experimentally manipulate stem cells of the adult brain. We outline how to prepare a precursor cell culture from naive brain tissue and how to test the stemness potential of different cell types present in that culture, which is achieved in a three-step paradigm. Following their isolation, stem/progenitor cells are expanded in neurosphere culture. Single cells obtained from these neurospheres are sorted for the expression of surface markers by flow cytometry. Finally, putative stem cells from cell sorting will be subjected to the so-called neural colony-forming cell assay, which allows discrimination between stem and progenitor cells. At the end of this chapter we will also describe how to identify neural stem cells in vivo.
|Therapeutic value of prenatal rapamycin treatment in a mouse brain model of tuberous sclerosis complex. |
Anderl, S; Freeland, M; Kwiatkowski, DJ; Goto, J
Human molecular genetics 20 4597-604 2011
Epileptic seizures, particularly infantile spasms, are often seen in infants with tuberous sclerosis complex (TSC) soon after birth. It is feared that there are long-term developmental and cognitive consequences from ongoing, frequent epilepsy. In addition, the hallmark brain pathology of TSC, cortical tubers and giant cells are fully developed at late gestational ages. These observations have led us to examine the benefit of prenatal rapamycin in a new fetal brain model of TSC. In this Tsc1(cc) Nes-cre(+) mouse model, recombination and loss of Tsc1 in neural progenitor cells leads to brain enlargement, hyperactivation of mTOR, and neonatal death on P0 due to reduced pup-maternal interaction. A single dose of prenatal rapamycin given to pregnant dams (1 mg/kg, subcutaneous) rescued the lethality of mutant mice. This one dose of prenatal rapamycin treatment reduced hyperactivation of the mTOR pathway in the mutant brain without causing apparent pregnancy loss. Continued postnatal rapamycin beginning at day 8 extended the survival of these mice to a median of 12 days with complete suppression of hyperactive mTOR. However, the rapamycin-treated mutants developed enlarged brains with an increased number of brain cells, displaying marked runting and developmental delay. These observations demonstrate the therapeutic benefit and limitations of prenatal rapamycin in a prenatal-onset brain model of TSC. Our data also suggest the possibility and limitations of this approach for TSC infants and mothers.
|Increased p75 neurotrophin receptor expression in the canine distemper virus model of multiple sclerosis identifies aldynoglial schwann cells that emerge in response to axonal damage. |
Imbschweiler I, Seehusen F, Peck CT, Omar M, Baumgärtner W, Wewetzer K
Gliogenesis under pathophysiological conditions is of particular clinical relevance since it may provide regeneration-promoting cells recruitable for therapeutic purposes. There is accumulating evidence that aldynoglial cells with Schwann cell-like growth-promoting properties emerge in the lesioned CNS. However, the characterization of these cells and the signals triggering their in situ generation have remained enigmatic. In the present study, we used the p75 neurotrophin receptor (p75(NTR) ) as a marker for Schwann cells to study gliogenesis in the well-defined canine distemper virus (CDV)-induced demyelination model. White matter lesions of CDV-infected dogs contained bi- to multipolar, p75(NTR) -expressing cells that neither expressed MBP, GFAP, BS-1, or P0 identifying oligodendroglia, astrocytes, microglia, and myelinating Schwann cells nor CDV antigen. Interestingly, p75(NTR) -expression became apparent prior to the onset of demyelination in parallel to the expression of β-amyloid precursor protein (β-APP), nonphosphorylated neurofilament (n-NF), BS-1, and CD3, and peaked in subacute lesions with inflammation. To study the role of infiltrating immune cells during differentiation of Schwann cell-like glia, organotypic slice cultures from the normal olfactory bulb were established. Despite the absence of infiltrating lymphocytes and macrophages, a massive appearance of p75(NTR) -positive Schwann-like cells and BS-1-positive microglia was noticed at 10 days in vitro. It is concluded that axonal damage as an early signal triggers the differentiation of tissue-resident precursor cells into p75(NTR) -expressing aldynoglial Schwann cells that retain an immature pre-myelin state. Further studies have to address the role of microglia during this process and the regenerative potential of aldynoglial cells in CDV infection and other demyelinating diseases. © 2011 Wiley-Liss, Inc.Copyright © 2011 Wiley-Liss, Inc.
|The Discoidin domain receptor 1 gene has a functional A2RE sequence. |
Roig B, Moyano S, Martorell L, Costas J, Vilella E
Journal of neurochemistry 2011
Discoidin domain receptor 1 (DDR1) is expressed in myelin oligodendrocytes and co-localizes with myelin basic protein (MBP). Alternative splicing of DDR1 generates five isoforms designated DDR1a-e. The MBP mRNA contains an A2RE sequence that is recognized by heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, which is responsible for transport of the MBP mRNA to oligodendrocyte processes. We hypothesized that DDR1 could have a functional A2RE sequence. By in silico analysis, we identified an A2RE-like sequence in the human DDR1 mRNA. We observed nuclear and dendrite cytoplasmic immunofluorescence, indicating that DDR1 and hnRNP A2/B1 co-localize in human oligodendrocytes and in differentiated HOG16 cells. The A2RE-like sequence of DDR1 contains the SNP rs2267641, and we found that in the human brain, the minor allele is associated with lower and higher levels DDR1b and DDR1c mRNA expression, respectively. Moreover, a positive correlation between DDR1c and the myelin genes MAG and OLIG2 was found. Differentiated HOG16 cells transfected with an hnRNP A2/B1 siRNA simultaneously show a decrease and an increase in the DDR1c and DDR1b mRNA expression levels, respectively, which was accompanied by a decrease in DDR1 protein levels at the cytoplasmic edges. These results suggest that the DDR1 A2RE sequence is functionally involved in the hnRNP A2/B1-mediated splicing and transport of the DDR1c mRNA.Journal of Neurochemistry © 2011 International Society for Neurochemistry.
|Reduced inflammation accompanies diminished myelin damage and repair in the NG2 null mouse spinal cord. |
Kucharova, K; Chang, Y; Boor, A; Yong, VW; Stallcup, WB
Journal of neuroinflammation 8 158 2011
Multiple sclerosis (MS) is a demyelinating disease in which blood-derived immune cells and activated microglia damage myelin in the central nervous system. While oligodendrocyte progenitor cells (OPCs) are essential for generating oligodendrocytes for myelin repair, other cell types also participate in the damage and repair processes. The NG2 proteoglycan is expressed by OPCs, pericytes, and macrophages/microglia. In this report we investigate the effects of NG2 on these cell types during spinal cord demyelination/remyelination.Demyelinated lesions were created by microinjecting 1% lysolecithin into the lumbar spinal cord. Following demyelination, NG2 expression patterns in wild type mice were studied via immunostaining. Immunolabeling was also used in wild type and NG2 null mice to compare the extent of myelin damage, the kinetics of myelin repair, and the respective responses of OPCs, pericytes, and macrophages/microglia. Cell proliferation was quantified by studies of BrdU incorporation, and cytokine expression levels were evaluated using qRT-PCR.The initial volume of spinal cord demyelination in wild type mice is twice as large as in NG2 null mice. However, over the ensuing 5 weeks there is a 6-fold improvement in myelination in wild type mice, versus only a 2-fold improvement in NG2 null mice. NG2 ablation also results in reduced numbers of each of the three affected cell types. BrdU incorporation studies reveal that reduced cell proliferation is an important factor underlying NG2-dependent decreases in each of the three key cell populations. In addition, NG2 ablation reduces macrophage/microglial cell migration and shifts cytokine expression from a pro-inflammatory to anti-inflammatory phenotype.Loss of NG2 expression leads to decreased proliferation of OPCs, pericytes, and macrophages/microglia, reducing the abundance of all three cell types in demyelinated spinal cord lesions. As a result of these NG2-dependent changes, the course of demyelination and remyelination in NG2 null mice differs from that seen in wild type mice, with both myelin damage and repair being reduced in the NG2 null mouse. These studies identify NG2 as an important factor in regulating myelin processing, suggesting that therapeutic targeting of the proteoglycan might offer a means of manipulating cell behavior in demyelinating diseases.Full Text Article
|Levetiracetam exhibits protective properties on rat Schwann cells in vitro. |
Stettner M, Dehmel T, Mausberg AK, Köhne A, Rose CR, Kieseier BC.
Journal of the peripheral nervous system : JPNS 16 250-60 2011
Oxidative stress and inflammation represent pathways causing substantial damage to the peripheral nervous system. Levetiracetam (LEV) is a commonly used antiepileptic drug targeting high-voltage activated N-type calcium channels. Recent evidence suggests that LEV may also act as a histone deacetylase inhibitor, suggesting that this drug exhibits both anti-inflammatory and anti-oxidative effects, and as such may represent an interesting candidate for treating inflammatory diseases affecting the peripheral nerve. Therefore, we analysed the influence of LEV ex vivo on purified Schwann cells from neonatal P3 rats as well as on dorsal root ganglia prepared from E15 rat embryos. LEV diminished a lipopolysaccharide (LPS)-induced increase of the pro-inflammatory signature molecules tumour necrosis factor alpha, matrix metalloproteinase 9 (MMP-9), and caspase 6. Furthermore, LEV decreased LPS-induced cell death and protected cells against oxidative stress in a glutamate-based oxidative stress model. MMP-2 activity, usually elevated during myelination and repair, was also found to be up-regulated following LEV, while LEV exhibited no negative effects on myelination. Intracellular sodium or calcium concentrations were unaltered by LEV. Thus, LEV may be a promising, well-tolerated drug that - besides its antiepileptic potential - mediates anti-inflammatory, anti-oxidative, and anti-apoptotic properties that may potentially be useful in treating diseases of the peripheral nerve.
|IkappaB kinase 2 determines oligodendrocyte loss by non-cell-autonomous activation of NF-kappaB in the central nervous system. |
Raasch, J; Zeller, N; van Loo, G; Merkler, D; Mildner, A; Erny, D; Knobeloch, KP; Bethea, JR; Waisman, A; Knust, M; Del Turco, D; Deller, T; Blank, T; Priller, J; Brück, W; Pasparakis, M; Prinz, M
Brain : a journal of neurology 134 1184-98 2011
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.
|Low level primary blast injury in rodent brain. |
Pun, PB; Kan, EM; Salim, A; Li, Z; Ng, KC; Moochhala, SM; Ling, EA; Tan, MH; Lu, J
Frontiers in neurology 2 19 2011
The incidence of blast attacks and resulting traumatic brain injuries has been on the rise in recent years. Primary blast is one of the mechanisms in which the blast wave can cause injury to the brain. The aim of this study was to investigate the effects of a single sub-lethal blast over pressure (BOP) exposure of either 48.9 kPa (7.1 psi) or 77.3 kPa (11.3 psi) to rodents in an open-field setting. Brain tissue from these rats was harvested for microarray and histopathological analyses. Gross histopathology of the brains showed that cortical neurons were "darkened" and shrunken with narrowed vasculature in the cerebral cortex day 1 after blast with signs of recovery at day 4 and day 7 after blast. TUNEL-positive cells were predominant in the white matter of the brain at day 1 after blast and double-labeling of brain tissue showed that these DNA-damaged cells were both oligodendrocytes and astrocytes but were mainly not apoptotic due to the low caspase-3 immunopositivity. There was also an increase in amyloid precursor protein immunoreactive cells in the white matter which suggests acute axonal damage. In contrast, Iba-1 staining for macrophages or microglia was not different from control post-blast. Blast exposure altered the expression of over 5786 genes in the brain which occurred mostly at day 1 and day 4 post-blast. These genes were narrowed down to 10 overlapping genes after time-course evaluation and functional analyses. These genes pointed toward signs of repair at day 4 and day 7 post-blast. Our findings suggest that the BOP levels in the study resulted in mild cellular injury to the brain as evidenced by acute neuronal, cerebrovascular, and white matter perturbations that showed signs of resolution. It is unclear whether these perturbations exist at a milder level or normalize completely and will need more investigation. Specific changes in gene expression may be further evaluated to understand the mechanism of blast-induced neurotrauma.
|Bipolar electrocautery: A rodent model of Sunderland third-degree nerve injury. |
Moradzadeh A, Brenner MJ, Whitlock EL, Tong AY, Luciano JP, Hunter DA, Myckatyn TM, Mackinnon SE
Archives of facial plastic surgery : official publication for the American Academy of Facial Plastic and Reconstructive Surgery, Inc. and the International Federation of Facial Plastic Surgery Societies 12 40-7 2010
OBJECTIVE: To determine the Sunderland classification of a bipolar electrocautery injury. METHODS: Twenty-two rats received crush (a reproducible Sunderland second-degree injury) or bipolar electrocautery injury and were evaluated for functional, histomorphometric, and immunohistochemical recovery at 21 or 42 days. Animal experiments were performed between July 3 and December 12, 2007. Axonal regeneration and end plate reinnervation were evaluated in double transgenic cyan fluorescent protein-conjugated Thy1 and green fluorescent protein-conjugated S100 mice. RESULTS: Compared with crush injury, bipolar electrocautery injury caused greater disruption of myelin and neurofilament architecture at the injury site and decreased nerve fiber counts and percentage of neural tissue distal to the injury (P =.007). Complete functional recovery was seen after crush but not bipolar electrocautery injury. Serial live imaging demonstrated axonal regeneration at week 1 after crush and at week 3 after bipolar electrocautery injury. Qualitative assessment of motor end plate reinnervation at 42 days demonstrated complete neuromuscular end plate reinnervation in the crush group and only limited reinnervation in the bipolar electrocautery group. CONCLUSION: Bipolar electrocautery injury in a rodent model resulted in a Sunderland third-degree injury, characterized by gradual, incomplete recovery without intervention.
|Hypomyelination in three Weimaraner dogs. |
Y Millán,J Mascort,A Blanco,C Costa,D Masian,S Guil-Luna,M Pumarola,J Martin de Las Mulas
The Journal of small animal practice 51 2010
Hypomyelination syndrome of the Weimaraner dog is a disease characterised by a reduction or absence of myelin in the axons of the central nervous system (CNS) exclusively. The objective of this study was to analyse the cause of this deficiency of myelin. Tissue samples of the CNS of three Weimaraner dogs with neurological signs were fixed in 10% formalin and embedded in paraffin wax, and histochemical, immunohistochemical and ultrastructural studies were performed. Histochemical staining with haematoxylin and eosin and Kluver-Barrera techniques showed generalised pallor in the peripheral areas of the ventral and lateral funiculi of the spinal cord. Immunohistochemical analysis showed a weak expression of both proteolipid protein (PLP) and myelin basic protein (MBP) and a marked decrease of Olig2(+) cells in the demyelinated areas. The immunohistochemical findings suggested a myelination or remyelination failure because of the smaller population of oligodendrocytes. However, PLP gene mutations may also be the cause of the decrease of PLP expression as described in other species.
|Expression of the tyrosine kinase discoidin domain receptor 1 (DDR1) in human central nervous system myelin. |
Bàrbara Roig,Neus Franco-Pons,Lourdes Martorell,Jordi Tomàs,Wolfgang F Vogel,Elisabet Vilella
Brain research 1336 2010
During development of the mouse brain, the protein kinase discoidin domain receptor 1 (DDR1) is present prenatally in neurons of the proliferative areas, and postnatally, DDR1 expression is no longer detected in neurons, but a spatial-temporal expression pattern in oligodendrocytes that overlaps with the dynamics of the myelination process is detected. Notably, oligodendrocytic DDR1 expression is upregulated in mice during experimentally induced remyelination. Recently, we demonstrated that DDR1 expression is high in human brain and that there is an association between the gene and schizophrenia in a case-control study. However, data regarding expression of DDR1 in the human brain are scarce. Here, we describe the expression pattern of DDR1 in the human adult cerebral cortex. Using several immunohistological techniques and in situ hybridization, we identified DDR1 in the following: a) myelin, b) capillary endothelial cells in the gray as well as white matter, and c) in the soma of some oligodendrocytes and astrocytes in the white matter. The most important overall finding in this study was that DDR1 is present in myelin and is expressed by oligodendrocyte cells. We detected the presence of DDR1 mRNA and protein in myelin and observed that DDR1 co-localized with the classical myelin basic protein (MBP). Moreover, we found a strong positive correlation between expression levels of DDR1 and two myelin-associated genes, myelin-associated glycoprotein (MAG) and oligodendrocyte transcription factor 2 (OLIG2). These observations suggest that DDR1 could be an important constituent of myelin. Because defects in myelination are linked to several mental disorders such as schizophrenia, the function of DDR1 in the process of myelination warrants further investigation.
|Human embryonic stem cell neural differentiation and enhanced cell survival promoted by hypoxic preconditioning. |
Francis, KR; Wei, L
Cell death & disease 1 e22 2010
Transplantation of neural progenitors derived from human embryonic stem cells (hESCs) provides a potential therapy for ischemic stroke. However, poor graft survival within the host environment has hampered the benefits and applications of cell-based therapies. The present investigation tested a preconditioning strategy to enhance hESC tolerance, thereby improving graft survival and the therapeutic potential of hESC transplantation. UC06 hESCs underwent neural induction and terminal differentiation for up to 30 days, becoming neural lineage cells, exhibiting extensive neurites and axonal projections, generating synapses and action potentials. To induce a cytoprotective phenotype, hESC-derived neurospheres were cultured at 0.1% oxygen for 12 h, dissociated and plated for terminal differentiation under 21% oxygen. Immunocytochemistry and electrophysiology demonstrated the 'hypoxic preconditioning' promoted neuronal differentiation. Western blotting revealed significantly upregulated oxygen-sensitive transcription factors hypoxia-inducible factor (HIF)-1α and HIF-2α, while producing a biphasic response within HIF targets, including erythropoietin, vascular endothelial growth factor and Bcl-2 family members, during hypoxia and subsequent reoxygenation. This cytoprotective phenotype resulted in a 50% increase in both total and neural precursor cell survival after either hydrogen peroxide insult or oxygen-glucose deprivation. Cellular protection was maintained for at least 5 days and corresponded to upregulation of neuroprotective proteins. These results suggest that hypoxic preconditioning could be used to improve the effectiveness of human neural precursor transplantation therapies.Full Text Article
|Longitudinal study of Australian stringhalt cases in France. |
C Domange,A Casteignau,G Collignon,M Pumarola,N Priymenko
Journal of animal physiology and animal nutrition 94 2010
Seventy horses with clinical evidence of Australian stringhalt were studied in France from 2003 to 2008. All horses but one had history of bilateral stringhalt and grazed pastures infested with Hypochoeris radicata (L.). They displayed hind limbs hyperflexion and an abnormal gait because of a distal axonopathy with a skeletal muscle denervation and atrophy. Fifty percentage of them recovered spontaneously in 8 months, and only the more affected horses were unable to recover even if they looked healthy on dry and hot days. Clinical troubles revealed also depression or aggressive behaviour, suggesting that central nervous system might be affected. Treatment with phenytoin resulted in a rapid noticeable improvement of stringhalt in some horses but the administration of taurine seems to improve behavioural disorders. Deeply affected horses (grade III and more of Huntington's classification at the beginning) must be treated with phenytoin when the weather is muddy and damp because they still display stringhalt when they are afraid or at the beginning of the work.
|Brain-derived neurotrophic factor promotes central nervous system myelination via a direct effect upon oligodendrocytes. |
Xiao, J; Wong, AW; Willingham, MM; van den Buuse, M; Kilpatrick, TJ; Murray, SS
Neuro-Signals 18 186-202 2010
The extracellular factors that are responsible for inducing myelination in the central nervous system (CNS) remain elusive. We investigated whether brain-derived neurotrophic factor (BDNF) is implicated, by first confirming that BDNF heterozygous mice exhibit delayed CNS myelination during early postnatal development. We next established that the influence of BDNF upon myelination was direct, by acting on oligodendrocytes, using co-cultures of dorsal root ganglia neurons and oligodendrocyte precursor cells. Importantly, we found that BDNF retains its capacity to enhance myelination of neurons or by oligodendrocytes derived from p75NTR knockout mice, indicating the expression of p75NTR is not necessary for BDNF-induced myelination. Conversely, we observed that phosphorylation of TrkB correlated with myelination, and that inhibiting TrkB signalling also inhibited the promyelinating effect of BDNF, suggesting that BDNF enhances CNS myelination via activating oligodendroglial TrkB-FL receptors. Together, our data reveal a previously unknown role for BDNF in potentiating the normal development of CNS myelination, via signalling within oligodendrocytes.
|Extensive infiltration of neutrophils in the acute phase of experimental autoimmune encephalomyelitis in C57BL/6 mice. |
Fenglan Wu,Wei Cao,Yiqing Yang,Ailian Liu
Histochemistry and cell biology 133 2010
To determine the possible involvement of neutrophils in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), we examined their infiltration pattern during the course of MOG35-55-induced EAE in the C57BL/6 mice. Using immunohistochemistry and flow cytometry, we found that the number of neutrophils was significantly increased during onset of disease, remained high at the peak stage and dramatically declined thereafter. Moreover, dual labeling provided anatomical evidence of a prominent accumulation of neutrophils in the center and vicinity of lesion areas of demyelination, axonal loss or axonal degeneration at early stages of EAE. These observations provide evidence that neutrophils are one of the major sources of inflammatory cells to initiate EAE, which suggest that neutrophils may contribute to demyelination and axonal degeneration in the acute phase of EAE and play a greater role than previously thought in the pathogenesis of EAE.
|The NG2 proteoglycan promotes oligodendrocyte progenitor proliferation and developmental myelination. |
Kucharova, K; Stallcup, WB
Neuroscience 166 185-94 2010
The NG2 proteoglycan has been shown to promote proliferation and motility in a variety of cell types. The presence of NG2 on oligodendrocyte progenitor cells (OPCs) suggests that the proteoglycan may be a factor in expansion of the OPC pool to fill the entire CNS prior to OPC differentiation to form myelinating oligodendrocytes. Comparisons of postnatal cerebellar myelination in wild type and NG2 null mice reveal reduced numbers of OPCs in developing white matter of the NG2 null mouse. Quantification of BrdU incorporation shows that reduced proliferation is a key reason for this OPC shortage, with the peak of OPC proliferation delayed by 4-5 days in the absence of NG2. As a result of the subnormal pool of OPCs, there is also a delay in production of mature oligodendrocytes and myelinating processes in the NG2 null cerebellum. NG2 may promote OPC proliferation via enhancement of growth factor signaling or mediation of OPC interaction with unmyelinated axons.
|Human remyelination promoting antibody inhibits apoptotic signaling and differentiation through Lyn kinase in primary rat oligodendrocytes. |
Watzlawik, J; Holicky, E; Edberg, DD; Marks, DL; Warrington, AE; Wright, BR; Pagano, RE; Rodriguez, M
Glia 58 1782-93 2010
Human remyelination promoting IgM mAbs target oligodendrocytes (OLs) and function in animal models of multiple sclerosis (MS). However, their mechanism of action is unknown. This study seeks to identify the cellular mechanism of action of a recombinant human IgM on OL survival.Binding of rHIgM22 to the surface of rat OLs was studied by co-localization with various markers. RHIgM22-mediated effects on apoptotic signaling in OLs, differentiation markers, and signaling molecules were detected by Western blotting and immunoprecipitation.RHIgM22 co-localized with integrin β3 but not other integrin β-chains in OLs. Downstream of integrin β3 we identified Src family kinase (SFK) Lyn as a key player of rHIgM22-mediated actions in OLs. Lyn immunoprecipitated in a complex together with integrin αvβ3 and PDGFαR. Lyn expression was 9-fold up-regulated and Lyn activation was 3-fold higher inrHIgM22-treated OL cultures compared with controls. RHIgM22 inhibited apoptotic signaling by greater than 10-fold reduction of caspase-3 and capsase-9 cleavage and reduced by 4-fold expression of differentiation markers MBP and MOG in OLs. SFK inhibitors PP2 and SU6656 inhibited Lyn activity and restored caspase-cleavage in OLs. A human IgM that did not promote remyelination and medium wereused as controls.rHIgM22 prevented apoptotic signaling andinhibited OL differentiation by Lyn implying thatIgM-mediated remyelination is due toprotection of OPC and OLs rather than promotion of OPC differentiation.
|Inflammatory proprotein convertase-matrix metalloproteinase proteolytic pathway in antigen-presenting cells as a step to autoimmune multiple sclerosis. |
Shiryaev SA, Remacle AG, Savinov AY, Chernov AV, Cieplak P, Radichev IA, Williams R, Shiryaeva TN, Gawlik K, Postnova TI, Ratnikov BI, Eroshkin AM, Motamedchaboki K, Smith JW, Strongin AY
The Journal of biological chemistry 284 30615-26 2009
Multiple sclerosis (MS) is a disease of the central nervous system with autoimmune etiology. Susceptibility to MS is linked to viral and bacterial infections. Matrix metalloproteinases (MMPs) play a significant role in the fragmentation of myelin basic protein (MBP) and demyelination. The splice variants of the single MBP gene are expressed in the oligodendrocytes of the central nervous system (classic MBP) and in the immune cells (Golli-MBPs). Our data suggest that persistent inflammation caused by environmental risk factors is a step to MS. We have discovered biochemical evidence suggesting the presence of the inflammatory proteolytic pathway leading to MS. The pathway involves the self-activated furin and PC2 proprotein convertases and membrane type-6 MMP (MT6-MMP/MMP-25) that is activated by furin/PC2. These events are followed by MMP-25 proteolysis of the Golli-MBP isoforms in the immune system cells and stimulation of the specific autoimmune T cell clones. It is likely that the passage of these autoimmune T cell clones through the disrupted blood-brain barrier to the brain and the recognition of neuronal, classic MBP causes inflammation leading to the further up-regulation of the activity of the multiple individual MMPs, the massive cleavage of MBP in the brain, demyelination, and MS. In addition to the cleavage of Golli-MBPs, MMP-25 proteolysis readily inactivates crystallin alphaB that is a suppressor of MS. These data suggest that MMP-25 plays an important role in MS pathology and that MMP-25, especially because of its restricted cell/tissue expression pattern and cell surface/lipid raft localization, is a promising drug target in MS.Full Text Article
|Mutation in the myelin proteolipid protein gene alters BK and SK channel function in the caudal medulla. |
Mayer CA, Macklin WB, Avishai N, Balan K, Wilson CG, Miller MJ
Respiratory physiology & neurobiology 169 303-314 2009
Proteolipid protein (Plp) gene mutation in rodents causes severe CNS dysmyelination, early death, and lethal hypoxic ventilatory depression (Miller et al., 2004). To determine if Plp mutation alters neuronal function critical for control of breathing, the nucleus tractus solitarii (nTS) of four rodent strains were studied: myelin deficient rats (MD), myelin synthesis deficient (Plp(msd)), and Plp(null) mice, as well as shiverer (Mbp(shi)) mice, a myelin basic protein mutant. Current-voltage relationships were analyzed using whole-cell patch-clamp in 300 microm brainstem slices. Voltage steps were applied, and inward and outward currents quantified. MD, Plp(msd), and Plp(null), but not Mbp(shi) neurons exhibited reduced outward current in nTS at P21. Apamin blockade of SK calcium-dependent currents and iberiotoxin blockade of BK calcium-dependent currents in the P21 MD rat demonstrated reduced outward current due to dysfunction of these channels. These results provide evidence that Plp mutation specifically alters neuronal excitability through calcium-dependent potassium channels in nTS.
|Insulin and IGF-I prevent brain atrophy and DNA loss in diabetes. |
Serbedzija, P; Madl, JE; Ishii, DN
Brain research 1303 179-94 2009
The aim of this study was to identify factors that regulate the bulk of adult brain mass, and test the hypothesis that concomitantly reduced insulin and insulin-like growth factor (IGF) levels are pathogenic for brain atrophy associated with impaired learning and memory in diabetes. Doses of insulin, or insulin plus IGF-I that were too small to prevent hyperglycemia were infused for 12 weeks into the brain lateral ventricles of streptozotocin-diabetic adult rats. Brain wet, water and dry weights were significantly decreased in diabetic rats; insulin prevented these decreases. The decrease in brain DNA and protein contents in diabetic rats was prevented by the combination treatment, but not by insulin alone. Levels of several glia- and neuron-associated proteins were reduced in diabetes; these reductions were also prevented by the combination treatment. Although hyperglycemia was not prevented in plasma or cerebrospinal fluid, insulin prevented brain atrophy but not bulk DNA loss in diabetes, whereas the combination prevented both. Insulin actively prevented the loss of brain water content as well. Brain atrophy is associated with concomitantly reduced levels of insulin and IGF in other disorders such as Alzheimer's disease.
|Nogo-A and myelin-associated glycoprotein differently regulate oligodendrocyte maturation and myelin formation. |
Pernet, V; Joly, S; Christ, F; Dimou, L; Schwab, ME
The Journal of neuroscience : the official journal of the Society for Neuroscience 28 7435-44 2008
Nogo-A is one of the most potent oligodendrocyte-derived inhibitors for axonal regrowth in the injured adult CNS. However, the physiological function of Nogo-A in development and in healthy oligodendrocytes is still unknown. In the present study, we investigated the role of Nogo-A for myelin formation in the developing optic nerve. By quantitative real-time PCR, we found that the expression of Nogo-A increased faster in differentiating oligodendrocytes than that of the major myelin proteins MBP (myelin basic protein), PLP (proteolipid protein)/DM20, and CNP (2',3'-cyclic nucleotide 3'-phosphodiesterase). The analysis of optic nerves and cerebella of mice deficient for Nogo-A (Nogo-A(-/-)) revealed a marked delay of oligodendrocyte differentiation, myelin sheath formation, and axonal caliber growth within the first postnatal month. The combined deletion of Nogo-A and MAG caused a more severe transient hypomyelination. In contrast to MAG(-/-) mice, Nogo-A(-/-) mutants did not present abnormalities in the structure of myelin sheaths and Ranvier nodes. The common binding protein for Nogo-A and MAG, NgR1, was exclusively upregulated in MAG(-/-) animals, whereas the level of Lingo-1, a coreceptor, remained unchanged. Together, our results demonstrate that Nogo-A and MAG are differently involved in oligodendrocyte maturation in vivo, and suggest that Nogo-A may influence also remyelination in pathological conditions such as multiple sclerosis.
|Response of a neuronal model of tuberous sclerosis to mammalian target of rapamycin (mTOR) inhibitors: effects on mTORC1 and Akt signaling lead to improved survival and function. |
Meikle, L; Pollizzi, K; Egnor, A; Kramvis, I; Lane, H; Sahin, M; Kwiatkowski, DJ
The Journal of neuroscience : the official journal of the Society for Neuroscience 28 5422-32 2008
Tuberous sclerosis (TSC) is a hamartoma syndrome attributable to mutations in either TSC1 or TSC2 in which brain involvement causes epilepsy, mental retardation, and autism. We have reported recently (Meikle et al., 2007) a mouse neuronal model of TSC in which Tsc1 is ablated in most neurons during cortical development. We have tested rapamycin and RAD001 [40-O-(2-hydroxyethyl)-rapamycin], both mammalian target of rapamycin mTORC1 inhibitors, as potential therapeutic agents in this model. Median survival is improved from 33 d to more than 100 d; behavior, phenotype, and weight gain are all also markedly improved. There is brain penetration of both drugs, with accumulation over time with repetitive treatment, and effective reduction of levels of phospho-S6, a downstream target of mTORC1. In addition, there is restoration of phospho-Akt and phospho-glycogen synthase kinase 3 levels in the treated mice, consistent with restoration of Akt function. Neurofilament abnormalities, myelination, and cell enlargement are all improved by the treatment. However, dysplastic neuronal features persist, and there are only modest changes in dendritic spine density and length. Strikingly, mice treated with rapamycin or RAD001 for 23 d only (postnatal days 7-30) displayed a persistent improvement in phenotype, with median survival of 78 d. In summary, rapamycin/RAD001 are highly effective therapies for this neuronal model of TSC, with benefit apparently attributable to effects on mTORC1 and Akt signaling and, consequently, cell size and myelination. Although caution is appropriate, the results suggest the possibility that rapamycin/RAD001 may have benefit in the treatment of TSC brain disease, including infantile spasms.
|A mouse model of tuberous sclerosis: neuronal loss of Tsc1 causes dysplastic and ectopic neurons, reduced myelination, seizure activity, and limited survival. |
Meikle, L; Talos, DM; Onda, H; Pollizzi, K; Rotenberg, A; Sahin, M; Jensen, FE; Kwiatkowski, DJ
The Journal of neuroscience : the official journal of the Society for Neuroscience 27 5546-58 2007
Tuberous sclerosis (TSC) is a hamartoma syndrome caused by mutations in TSC1 or TSC2 in which cerebral cortical tubers and seizures are major clinical issues. We have engineered mice in which most cortical neurons lose Tsc1 expression during embryonic development. These Tsc1 mutant mice display several neurological abnormalities beginning at postnatal day 5 with subsequent failure to thrive and median survival of 35 d. The mice also display clinical and electrographic seizures both spontaneously and with physical stimulation, and some seizures end in a fatal tonic phase. Many cortical and hippocampal neurons are enlarged and/or dysplastic in the Tsc1 mutant mice, strongly express phospho-S6, and are ectopic in multiple sites in the cortex and hippocampus. There is a striking delay in myelination in the mutant mice, which appears to be caused by an inductive neuronal defect. This new TSC brain model replicates several features of human TSC brain lesions and implicates an important function of Tsc1/Tsc2 in neuronal development.
|Fate of endogenous stem/progenitor cells following spinal cord injury. |
Horky, LL; Galimi, F; Gage, FH; Horner, PJ
The Journal of comparative neurology 498 525-38 2006
The adult mammalian spinal cord contains neural stem and/or progenitor cells that slowly multiply throughout life and differentiate exclusively into glia. The contribution of adult progenitors to repair has been highlighted in recent studies, demonstrating extensive cell proliferation and gliogenesis following central nervous system (CNS) trauma. The present experiments aimed to determine the relative roles of endogenously dividing progenitor cells versus quiescent progenitor cells in posttraumatic gliogenesis. Using the mitotic indicator bromodeoxyuridine (BrdU) and a retroviral vector, we found that, in the adult female Fisher 344 rat, endogenously dividing neural progenitors are acutely vulnerable in response to T8 dorsal hemisection spinal cord injury. We then studied the population of cells that divide postinjury in the injury epicenter by delivering BrdU or retrovirus at 24 hours after spinal cord injury. Animals were euthanized at five timepoints postinjury, ranging from 6 hours to 9 weeks after BrdU delivery. At all timepoints, we observed extensive proliferation of ependymal and periependymal cells that immunohistochemically resembled stem/progenitor cells. BrdU+ incorporation was noted to be prominent in NG2-immunoreactive progenitors that matured into oligodendrocytes, and in a transient population of microglia. Using a green fluorescence protein (GFP) hematopoietic chimeric mouse, we determined that 90% of the dividing cells in this early proliferation event originate from the spinal cord, whereas only 10% originate from the bone marrow. Our results suggest that dividing, NG2-expressing progenitor cells are vulnerable to injury, but a separate, immature population of neural stem and/or progenitor cells is activated by injury and rapidly divides to replace this vulnerable population.
|Expression pattern of NOGO-A protein in the human nervous system. |
A Buss, B Sellhaus, A Wolmsley, J Noth, M E Schwab, G A Brook
Acta neuropathologica 110 113-9 2005
The distribution pattern of NOGO-A protein, an important axon growth inhibitory molecule and member of the reticulon family, has been investigated in the adult human brain, spinal cord, retina and dorsal root ganglia. Intense NOGO-A immunoreactivity was detected in oligodendroglial cell bodies and their myelin sheaths in nerve fibre tracts of the central nervous system. Furthermore, numerous populations of neurons in the brain and spinal cord expressed NOGO-A to a variable extent in their cell bodies and neurites, suggesting additional, as-yet-unknown, functions of this protein.
|Gradual loss of myelin and formation of an astrocytic scar during Wallerian degeneration in the human spinal cord. |
Buss, A; Brook, GA; Kakulas, B; Martin, D; Franzen, R; Schoenen, J; Noth, J; Schmitt, AB
Brain : a journal of neurology 127 34-44 2004
Axons undergo Wallerian degeneration distal to a point of injury. Experimental investigations have documented many of the cellular and molecular events that underlie this behaviour. Since relatively little is known about such events in human CNS pathologies and current experimental intervention strategies indicate the possibility of significant axon regeneration along the original degenerated fibre tract, we performed an immunohistochemical investigation of the dynamics of Wallerian degeneration in post mortem spinal cords of patients who died 2 days to 30 years after either cerebral infarction or traumatic spinal cord injury. Neurofilament (NF) staining demonstrated a spatio-temporal pattern of axonal loss within degenerating descending nerve fibre tracts that could be detected close to the lesion as early as 12 days after injury and progressed to an almost complete loss of NF immunoreactivity at survival times of 1 year and longer. Immunohistochemistry for glial fibrillary acidic protein revealed a late astrocytic reaction starting at 4 months after injury in the degenerating tracts, leading to the long-term deposition of a dense astrocytic scar. These events were accompanied by the gradual reduction of myelin basic protein in affected nerve fibre tracts, leading to almost complete loss by 3 years after injury. Since the extracellular matrix molecule chondroitin sulphate proteoglycan (CSPG) is known to be strongly inhibitory for axonal regeneration and to be a major component of gliotic scar tissues, we investigated the possible deposition of CSPG within the degenerating nerve fibre tracts. Apart from a local up-regulation close to the lesion site, our results show no enhanced CSPG expression within degenerated tracts at any survival time. This suggests that despite the apparent lack of CSPG in Wallerian degeneration, the slow reduction of CNS myelin and the long-term deposition of a dense astrocytic scar may present an environment that is non-supportive for axon regrowth.
|Remyelination of cytokine- or antibody-demyelinated CNS aggregate cultures is inhibited by macrophage supplementation. |
Lara T Diemel, Guus Wolswijk, Samuel J Jackson, M Louise Cuzner
Glia 45 278-86 2004
Remyelination in CNS aggregate cultures is determined both by macrophage enrichment and the mode of demyelination. Despite the same degree of myelin loss, accumulation of MBP in anti-MOG antibody-demyelinated aggregates overtakes that of controls, while recovery is significantly delayed following IFN-gamma-induced demyelination. In antibody-treated cultures, remyelination was associated with a significant increase in culture supernatant levels of TGF-beta1, FGF-2, and PDGF-AA as well as an induction of TNF-alpha immediately following removal of the demyelinating insult. The impaired recovery in IFN-gamma-treated cultures, denoted by a significant reduction in TGF-beta1, was reversed by treatment with hrTGF-beta1. Macrophage supplementation of the cultures prior to the addition of either demyelinating agent induced a greater degree of myelin loss followed by incomplete remyelination in both cases. This failure to remyelinate was associated in both groups with a several-fold elevation in TNF-alpha and with modest increases in PDGF-AA and FGF-2 in the antibody-treated cultures. In contrast, macrophage supplementation to mature cultures in the absence of any demyelinating treatment resulted in enhanced accumulation of MBP associated with a promyelinative growth factor and TNF-alpha profile similar to that in aggregates enriched with macrophages at the outset of the culture period. Hence, effector elements of the adaptive immune response appear to override promyelinogenic in favor of proinflammatory macrophage factors in mature CNS aggregates, counteracting the potential for myelin repair.
|Analysis of the K+ current profile of mature rat oligodendrocytes in situ. |
K Gipson, A Bordey
The Journal of membrane biology 189 201-12 2002
Previous studies have reported that mature oligodendrocytes (OLGs) in vitro display various voltage-dependent K+ currents while in situ OLGs show only voltage-independent K+ currents. Given this discrepancy and the lack of information on myelinating OLG ion channel expression in situ, we characterized mature OLG currents in myelinating corpus callosum slices from 17 to 36-day old rats. OLGs were recorded in cell-attached and whole-cell patch-clamp configurations, displayed morphology typical of mature OLGs, and stained positive for myelin basic protein. OLGs displayed large voltage-independent currents that decayed during the voltage pulse and small voltage-activated outward currents. The latter were blocked by TEA, activated between -40 and -50 mV, and decayed slowly. The former were composed of large voltage-independent, time-dependent Ba2+ (1 mM)-sensitive currents, and voltage-dependent Cs+ (5 mM) and Ba2+ (100 mM)-sensitive currents that reversed near the K+ equilibrium potential and inactivated at hyperpolarized potentials, identifying them as inwardly rectifying K+ currents. Inwardly rectifying single-channel K+currents could be recorded in the cell-attached configuration. The estimated single-channel slope conductance was 30 pS. The steady-state open probability was voltage-dependent and declined from 0.9 to 0.5 between -80 and -150 mV. Overall, mature OLGs in situ possess time- and also voltage-dependent K+ currents, which may facilitate clearance of K+ released during axonal firing.
|Anti-Myelin Basic Protein - Data Sheet|
|Reprogramming Cell Fate and Function Novel Strategies for iPSC Generation, Characterization, and Differentiation|