Suchergebnisse

The role of the neurovascular niche in CNS myelin regeneration is incompletely understood. Here, we show that, upon demyelination, CNS-resident pericytes (PCs) proliferate, and parenchymal non-vessel-associated PC-like cells (PLCs) rapidly develop. During remyelination, mature oligodendrocytes were found in close proximity to PCs. In Pdgfbret/ret mice, which have reduced PC numbers, oligodendrocyte progenitor cell (OPC) differentiation was delayed, although remyelination proceeded to completion. PC-conditioned medium accelerated and enhanced OPC differentiation in vitro and increased the rate of remyelination in an ex vivo cerebellar slice model of demyelination. We identified Lama2 as a PC-derived factor that promotes OPC differentiation. Thus, the functional role of PCs is not restricted to vascular homeostasis but includes the modulation of adult CNS progenitor cells involved in regeneration. ; This work was supported by research funds from Chilean FONDECYT Program CONICYT Grants 1161787 (to F.J.R.) and 1141015 (to L.F.B); Direccion de Investigación y Desarrollo-Universidad Austral de Chile (DID-UACh); Paracelsus Medical University PMU-FFF Long-Term Fellowship L-12/01/001-RIV (to F.J.R.) and Stand-Alone Grant E-12/15/077-RIT (to F.J.R. and A.T.); the European Union Seventh Framework Program (FP7/2007-2013) under Grant Agreements HEALTH-F2-2011-278850 (INMiND), HEALTH-F2-2011-279288 (IDEA), and FP7-REGPOT-316120 (GlowBrain); Austrian Science Fund FWF Special Research Program (SFB) F44 (F4413-B23) "Cell Signaling in Chronic CNS Disorders"; and State Government of Salzburg, Austria (Stiftungsprofessur and 20204-WISS/80/199-2014). In addition, this study was supported by grants from a core support grant from the Wellcome Trust (203151/Z/16/Z) and MRC to the Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute, the UK Multiple Sclerosis Society (941/11), the David and Isobel Walker Trust, "Investissements d'avenir" IHU-A-ICM and Obra Social La Caixa, the Swedish Science Council (2015-00550), the Swedish Cancer Foundation (15 0735), the Knut and Alice Wallenberg Foundation (2015.0030), the European Research Council (AdG 294556 BBBARRIER), and the Leducq Foundation (Sphingonet; 14CVD02). P.v.W. was supported by National Health & Medical Research Council of Australia Early Career Fellowship 628928. Work in A.K.'s group was funded by the Swiss National Science Foundation (31003A_159514/1; http://www.snf.ch/en) and The Synapsis Foundation (http://www.alzheimer-synapsis.ch).

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Upon demyelination, oligodendrocyte progenitor cells (OPCs) are activated and they proliferate, migrate and differentiate into myelin-producing oligodendrocytes. Besides OPCs, neural stem cells (NSCs) may respond to demyelination and generate oligodendrocytes. We have recently shown that CNS-resident pericytes (PCs) respond to demyelination, proliferate and secrete Laminin alpha2 (Lama2) that, in turn, enhances OPC differentiation. Here, we aimed to evaluate whether PCs influence the fate choice of NSCs in vitro, towards the production of new myelin-producing cells. Indeed, upon exposure to conditioned medium derived from PCs (PC-CM), the majority of NSCs gave rise to GalC- and myelin basic protein (MBP)-expressing oligodendrocytes at the expense of the generation of GFAP-positive astrocytes. Consistent with these findings, PC-CM induces an increase in the expression of the oligodendrocyte fate determinant Olig2, while the expression level of the astrocyte determinant ID2 is decreased. Finally, pre-incubation of PC-CM with an anti-Lama2 antibody prevented the generation of oligodendrocytes. Our findings indicate that PCs-derived Lama2 instructs NSCs to an oligodendrocyte fate choice favoring the generation of myelin-producing cells at the expense of astrocytes in vitro. Further studies aiming to reveal the role of PCs during remyelination may pave the way for the development of new therapies for the treatment of MS. ; The authors would like to thank the following funding agencies for their support: Paracelsus Medical University PMU-FFF Long-Term Fellowship L-12/01/001-RIV (to and Stand-Alone Grant E-12/15/077-RIT (both to F.J.R.); Chilean FONDECYT Program CONICYT Grant Nº 1161787 (F.J.R.), Grant Nº 1141015 (L.F.B); Chilean PCI Program CONICYT Grant Nº REDES170233, Grant Nº REDES180139 and Grant Nº REDI170037 (all to F.J.R); Chilean FONDEF-IDeA Program Grant Nº ID17AM0043 (M.E.S. and F.J.R.); the Bavarian State Ministry of Sciences, Research and the Arts (ForNeuroCell grant) (L.A.); the Germany Federal Ministry of Education and Research (BMBF grants #0312134, #01GG0706 and #01GN0505); European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreements n° HEALTH-F2-2011-278850 (INMiND) and HEALTH-F2-2011-279288 (IDEA). The work in the Franklin laboratory was supported by a programme grant from the UK Multiple Sclerosis Society and Adelson Medical Research Foundation and a core support grant from the Wellcome Trust and MRC to the Wellcome Trust-MRC Cambridge Stem Cell Institute. In addition, the present work was supported by the state of Salzburg (to L.A.).

We demonstrate enhanced differentiation of oligodendrocytes during neurogenesis of human embryonic stem cells (hESCs) using an extracellular matrix protein, vitronectin (VN). We show that VN is expressed in the ventral part of the developing human spinal cord. Combined treatment of retinoic acid, sonic hedgehog, and noggin in the presence of VN allows hESCs to differentiate into O4-positive oligodendrocytes. Particularly, VN profoundly promotes the derivation of oligodendrocyte progenitors that proliferate and differentiate into oligodendrocytes in response to mitogenic and survival factors. These results support the beneficial effect of VN on oligodendrocytic differentiation of hESCs. ; This research was supported by the Seoul Research and Business Development Program (10574) and by a Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea Government(MOST) (R01-2006-000-11364-0).

Oligodendrocyte progenitor cells (OPCs), which differentiate into myelinating oligodendrocytes during central nervous system (CNS) development, are the main proliferative cells in the adult brain. OPCs are conventionally considered a homogeneous population, particularly with respect to their electrophysiological properties, but this has been debated. We show, by using single-cell electrophysiological recordings, that OPCs start out as a homogeneous population, but become functionally heterogeneous, varying both within and between brain regions and with age. These electrophysiological changes in OPCs correlate with the differentiation potential of OPCs; thus, they may underlie the differentiational differences in OPCs between regions and likewise differentiation failure with age. ; We acknowledge the support of the Wellcome - MRC Cambridge Stem Cell Institute core facility managers, in particular for this work Dr Maike Paramor and Miss Victoria Murray with RNA sequencing, and all staff members of the University Biomedical Services (UBS). This project has received funding from: the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 771411; R.T.K, K.A.E); the Wellcome Trust, a Research Career Development Fellowship (R.T.K. and K.A.E. 091543/Z/10/Z) and a Studentship (102160/Z/13/Z; Y.K); The Paul G Allen Frontiers Group, Allen Distinguished Investigator Award (12076, R.T.K., D.K.V.); The Medical Research Council, a studentship (S.O.S.); The Gates Foundation, a Gates Scholarship (S.S.), The Biotechnology and Biological Sciences Research Council, a studentship (S.A.); Homerton College Cambridge, a Junior Research Fellowship (D.K.V); The UK MS Society, a Cambridge Myelin Repair Centre grant (50; R.T.K, O.D.F.); The Fonds de recherche du Québec-Santé, a scholarship (Y.K.); The Cambridge Commonwealth European & International Trust, a scholarship (Y.K.); and the Lister Institute, a Research Prize (R.T.K., K.A.E, SOS).

Acknowledgments: This study was supported by Instituto de Salud Carlos III (ISCiii) of Spain, co-financed by FEDER funds from European Union, through grants PI18/01557 (to AG), PI18/01556 (to JV), and CIBERNED (CB06/05/1116 to AG and CB06/05/0094 to JV); by Junta de Andalucia through Consejería de Economía y Conocimiento grants UMA18-FEDERJA-211 (to AG), PY18-RT-2233 (to AG) and US-1262734 (to JV) co-financed by Programa Operativo FEDER 2014-2020 and Consejeria de Salud grant PI-0276-2018 (to JAGL). ; Oligodendrocytes (OLs) are highly specialized cells of the central nervous system responsible for myelin production and metabolic support of neurons. Defects in OLs are crucial in several neurodegenerative diseases including multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Scarce access to primary samples and lack of efficient protocols to generate OLs from human pluripotent stem cells (hPSCs) are hampering our understanding of OL biology and the development of novel therapies. To promote the conversion of hPSCs into OLs, we have screened for a number of transcription factors (TFs) previously reported to be involved in OL generation. We found that the overexpression of SOX10 was sufficient to generate O4+ oligodendrocyte precursor cells (OPCs) from hPSCs only 10 days after SOX10 induction. Generated OPCs expressed mature OL proteins as MBP or MOG. At the transcriptome level, generated OPCs resembled primary OPCs. To test the functionality of generated OPCs, O4+ cells were co-cultured together with neurons, finding that O4+ cells were able to myelinate the neurons. Moreover, O4+ cells were injected intracerebrally in newborn shiverer RAG2-/- mice, finding that generated OLs extended within the corpus callosum and generated functional myelin, demonstrating the functionality of generated cells also in vivo. The protocol also describes an alternative for viral transduction, by incorporating an inducible SOX10 in the safe harbor locus AAVS1, yielding ~100% pure OPCs. O4+ OPCs can be co-cultured with maturing hPSC-derived neurons in 96/384-well- format plates, allowing the screening of pro-myelinating compounds. We have developed a novel methodology for a fast (20 days from hPSC stage) and efficient generation of functional OLs, which allow testing of compounds involved in myelination. This technology will allow further studies to better understand human OL biology and the screening of potential compounds involved in myelination in a human setting. ; Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

Research journal article in the field of Neuroscience. The paper reports research data on EBI2 receptor expression in the cells of the CNS (oligodendrocyte progenitor cells, oligodendrocytes, microglia, neurons and astrocytes) and the effects of EBI2 receptor on remyelination in organotypic cerebellar slices. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 665778. National Science Centre, Poland, fellowship registration number POLONEZ 2: 2016/21/P/NZ3/00897.

The most frequent variant of multiple sclerosis (MS) is the relapsing-remitting form, characterized by symptomatic phases followed by periods of total/partial recovery. Hence, it is possible that these patients can benefit from endogenous agents that control the inflammatory process and favor spontaneous remyelination. In this context, there is increasing interest in the role of myeloid-derived suppressor cells (MDSCs) during the clinical course of experimental autoimmune encephalomyelitis (EAE). MDSCs speed up infiltrated T-cell anergy and apoptosis. In different animal models of MS, a milder disease course is related to higher presence/density of MDSCs in the periphery, and smaller demyelinated lesions in the central nervous system (CNS). These observations lead us to wonder whether MDSCs might not only exert an anti-inflammatory effect but might also have direct influence on oligodendrocyte precursor cells (OPCs) and remyelination. In the present work, we reveal for the first time the relationship between OPCs and MDSCs in EAE, relationship that is guided by the distance from the inflammatory core. We describe the effects of MDSCs on survival, proliferation, as well as potent promoters of OPC differentiation toward mature phenotypes. We show for the first time that osteopontin is remarkably present in the analyzed secretome of MDSCs. The ablation of this cue from MDSCs-secretome demonstrates that osteopontin is the main MDSC effector on these oligodendroglial cells. These data highlight a crucial pathogenic interaction between innate immunity and the CNS, opening ways to develop MDSC- and/or osteopontin-based therapies to promote effective myelin preservation and repair in MS patients. ; This work was supported by the Spanish Ministerio de Economía, Industria y Competitividad-MINEICO (currently Ministerio de Ciencia e Innovación: grants SAF2012-40023, SAF2015-72325-EXP, SAF2016-77575-R, and PID2019-109858RB-I00); the Instituto de Salud Carlos III (grants RD12-0032-12, RD16-0015-0019, PI15-00963, and PI18-00357—partially financed by F.E.D.E.R.: European Union "Una manera de hacer Europa"-); the Spanish Research Council/Consejo Superior de Investigaciones Científicas-CSIC (grants CSIC-2015201023, 2019AEP033, and LINKA20268); and ADEM-TO (Spain), ATORDEM (Spain), AELEM (Spain), and ARSEP Foundations (France). D. C. and R. L. G. were financed by SESCAM. C. M.-J. held a BES-2013-062630 predoctoral Research Training contract from MINEICO (associated with SAF2012-40023 and PI15-00963) and a contract under SAF2015-72325-EXP and SAF2016-77575-R. B. F.-G. is currently contracted under IND2018/BMD-9751 (Comunidad de Madrid, Spain). M. C. O holds a postdoctoral contract from the Consejería de Sanidad de Castilla-La Mancha (II-2018_07). Dr Clemente's group was sponsored by Aciturri Aeronáutica SLA, Fundación Galletas Coral, and Embutidos y Jamones España e Hijos.

The establishment and operation of the nervous system requires genetic regulation by a network of DNA‐binding proteins, among which is the zinc finger superfamily of transcription factors. We have cloned and characterized a member of the unusual Cys‐Cys‐His‐Cys (also referred to as Cys2HisCys, CCHC, or C2HC) class of zinc finger proteins in the developing nervous system. The novel gene, Myt1‐like (Myt1l), is highly homologous to the original representative of this class, Myelin transcription factor 1 (Myt1) (Kim and Hudson, 1992). The MYT1 gene maps to human chromosome 20, while MYT1L maps to a region of human chromosome 2. Both zinc finger proteins are found in neurons at early stages of differentiation, with germinal zone cells displaying intense staining for MyT1. Unlike Myt1, Myt1l has not been detected in the glial lineage. Neurons that express Myt1l also express TuJ1, which marks neurons around the period of terminal mitosis. The Myt1l protein resides in distinct domains within the neuronal nucleus, analogous to the discrete pattern previously noted for Myt1 (Armstrong et al.: 14:303–321, 1995). The developmental expression and localization of these two multifingered CCHC proteins suggests that each may play a role in the development of neurons and oligodendroglia in the mammalian central nervous system. J. Neurosci. Res. 50:272–290, 1997. This article is a US government work and, as such, is in the public domain in the United States of America.

Publisher's version (útgefin grein) ; Plasticity in the central nervous system (CNS) allows for responses to changing environmental signals. While the majority of studies on brain plasticity focus on neuronal synapses, myelin plasticity has now begun to emerge as a potential modulator of neuronal networks. Oligodendrocytes (OLs) produce myelin, which provides fast signal transmission, allows for synchronization of neuronal inputs, and helps to maintain neuronal function. Thus, myelination is also thought to be involved in learning. OLs differentiate from oligodendrocyte precursor cells (OPCs), which are distributed throughout the adult brain, and myelination continues into late adulthood. This process is orchestrated by numerous cellular and molecular signals, such as axonal diameter, growth factors, extracellular signaling molecules, and neuronal activity. However, the relative importance of, and cooperation between, these signaling pathways is currently unknown. In this review, we focus on the current knowledge about myelin plasticity in the CNS. We discuss new insights into the link between this type of plasticity, learning and behavior, as well as mechanistic aspects of myelin formation that may underlie myelin plasticity, highlighting OPC diversity in the CNS. ; This work was supported by the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (Grant Agreement No. 771411; RK, GB, and KE); a Wellcome Studentship (102160/Z/13/Z; YK), the Fonds de recherche du Québec-Santé, a scholarship (YK); the Cambridge Commonwealth European and International Trust, a scholarship (YK); and the Lister Institute, a Research Prize (RK). ; Peer Reviewed

When the central-peripheral transitional node first appears it lies immediately distal to the astrocyte processes delineating the cord surface. Its initial location may be influenced indirectly by the astrocytes, since they determine the position of the transitional Schwann cell by preventing it from invading the central nervous system. The central end of the Schwann cell becomes specialised to form a narrow cytoplasmic collar which closely envelopes, and so may influence, the developing nodal axon segment. The earliest nodal specializations include subaxolemmal undercoating which first appears as discrete plaques. These soon fuse to form a complete layer. The transitional node is closely related to the Schwann cell collar throughout its maturation. However, the presumptive oligodendrocyte paranode lies a considerable distance central to the node for some time. The intervening axon segment is enveloped by astrocyte processes. Terminal pockets of the oligodendrocyte gradually extend distally along this segment until they reach the node. Here the distal end of the oligodendrocyte is at first apposed to the Schwann cell collar. With maturation, astrocyte processes extend into the node gap, intervening between the two. The Schwann collar gradually becomes retracted distally as it gives rise to microvilli which project into the node gap space. With maturation, the astrocyte processes form a progressively more complete barrier between the oligodendrocyte and the node gap space. As the myelin sheaths on either side of the transitional node become thicker, the angles through which their turns incline inwards towards the axon progressively increase. The node gap thus tends to become deeper and to be bounded by steeper walls. However, in small fibres and in a proportion of large fibres, this angle remains relatively small and the node gap is therefore relatively open. Axonal protrusions commonly arise from the nodal and the paranodal segments of the axon. With maturation they become more frequent at the latter. Small ...

Graphene, graphene-based nanomaterials (GBNs), and carbon nanotubes (CNTs) are being investigated as potential substrates for the growth of neural cells. However, in most in vitro studies, the cells were seeded on these materials coated with various proteins implying that the observed effects on the cells could not solely be attributed to the GBN and CNT properties. Here, we studied the biocompatibility of uncoated thermally reduced graphene (TRG) and poly(vinylidene fluoride) (PVDF) membranes loaded with multi-walled CNTs (MWCNTs) using neural stem cells isolated from the adult mouse olfactory bulb (termed aOBSCs). When aOBSCs were induced to differentiate on coverslips treated with TRG or control materials (polyethyleneimine-PEI and polyornithine plus fibronectin-PLO/F) in a serum-free medium, neurons, astrocytes, and oligodendrocytes were generated in all conditions, indicating that TRG permits the multi-lineage differentiation of aOBSCs. However, the total number of cells was reduced on both PEI and TRG. In a serum-containing medium, aOBSC-derived neurons and oligodendrocytes grown on TRG were more numerous than in controls; the neurons developed synaptic boutons and oligodendrocytes were more branched. In contrast, neurons growing on PVDF membranes had reduced neurite branching, and on MWCNTs-loaded membranes oligodendrocytes were lower in numbers than in controls. Overall, these findings indicate that uncoated TRG may be biocompatible with the generation, differentiation, and maturation of aOBSC-derived neurons and glial cells, implying a potential use for TRG to study functional neuronal networks. ; This work was funded by grants from the European Union in the 7th Framework Program research project "HARCANA" (Grant Agreement No. NMP3-LA-2008-213277) to CV-A, ML-M, VA, and CJ, and the Spanish Ministerio de Economía y Competitividad (MINECO: CIBERNED CB06/05/0065, SAF2013-47596R, and CSIC 201220E098) to CV-A, and MINECO (MAT2013-48107-C3) to RV, and from Millipore Iberica (Ref. no: 050601140007) to RM-M. CERM is grateful to IAP (7-05 FS2) and FRS-FNRS for financial support. ; Peer reviewed ; Peer Reviewed