胶质瘢痕和胶质细胞(英文)

A pericyte origin of spinal cord scar tissue G ritz C Dias DO Tomilin N Barbacid M Shupliakov O Fris n J Source Department of Cell and Molecular Biology Karolinska Institute Stockholm Sweden Abstract There is limited regeneration of lost tissue after central nervous system injury and the lesion is sealed with a scar The role of the scar which often is referred to as the glial scar because of its abundance of astrocytes is complex and has been discussed for more than a century Here we show that a specific pericyte subtype gives rise to scar forming stromal cells which outnumber astrocytes in the injured spinal cord Blocking the generation of progeny by this pericyte subtype results in failure to seal the injured tissue The formation of connective tissue is common to many injuries and pathologies and here we demonstrate a cellular origin of fibrosis Hepatic stellate cells and astrocytes Stars of scar formation and tissue repair Schachtrup C Le Moan N Passino MA Akassoglou K Source University of California at San Francisco San Francisco CA USA Abstract Scar formation inhibits tissue repair and regeneration in the liver and central nervous system Activation of hepatic stellate cells HSCs after liver injury or of astrocytes after nervous system damage is considered to drive scar formation HSCs are the fibrotic cells of the liver as they undergo activation and acquire fibrogenic properties after liver injury HSC activation has been compared to reactive gliosis of astrocytes which acquire a reactive phenotype and contribute to scar formation after nervous system injury much like HSCs after liver injury It is intriguing that a wide range of neuroglia related molecules are expressed by HSCs We identified an unexpected role for the p75 neurotrophin receptor in regulating HSC activation and liver repair Here we discuss the molecular mechanisms that regulate HSC activation and reactive gliosis and their contributions to scar formation and tissue repair Juxtaposing key mechanistic and functional similarities in HSC and astrocyte activation might provide novel insight into liver regeneration and nervous system repair PMID 21555919 PubMed in process PMCID PMC3142460 Available on 2012 6 1 The unusual response of serotonergic neurons after CNS Injury lack of axonal dieback and enhanced sprouting within the inhibitory environment of the glial scar Hawthorne AL Hu H Kundu B Steinmetz MP Wylie CJ Deneris ES Silver J Source Department of Neurosciences Case Western Reserve University Cleveland Ohio 44106 and Department of Neurosurgery Cleveland Clinic Foundation Cleveland Ohio 44195 USA Abstract Serotonergic neurons possess an enhanced ability to regenerate or sprout after many types of injury To understand the mechanisms that underlie their unusual properties we used a combinatorial approach comparing the behavior of serotonergic and cortical axon tips over time in the same injury environment in vivo and to growth promoting or growth inhibitory substrates in vitro After a thermocoagulatory lesion in the rat frontoparietal cortex callosal axons become dystrophic and die back Serotonergic axons however persist within the lesion edge At the third week post injury 5 HT axons sprout robustly The lesion environment contains both growth inhibitory chondroitin sulfate proteoglycans CSPGs and growth promoting laminin Transgenic mouse serotonergic neurons specifically labeled by enhanced yellow fluorescent protein under control of the Pet 1 promoter enhancer or cortical neurons were cultured on low amounts of laminin with or without relatively high concentrations of the CSPG aggrecan Serotonergic neurons extended considerably longer neurites than did cortical neurons on low laminin and exhibited a remarkably more active growth cone on low laminin plus aggrecan during time lapse imaging than did cortical neurons Chondroitinase ABC treatment of laminin CSPG substrates resulted in significantly longer serotonergic but not cortical neurite lengths This increased ability of serotonergic neurons to robustly grow on high amounts of CSPG may be partially due to significantly higher amounts of growth associated protein 43 and or 1 integrin than cortical neurons Blocking 1 integrin decreased serotonergic and cortical outgrowth on laminin Determining the mechanism by which serotonergic fibers persist and sprout after lesion could lead to therapeutic strategies for both stroke and spinal cord injury Human neuropathological and animal model evidence supporting a role for Fas mediated apoptosis and inflammation in cervical spondylotic myelopathy Yu WR Liu T Kiehl TR Fehlings MG Source Department of Pathology Toronto Western Research Institute Krembil Neuroscience Centre Toronto Western Hospital University Health Network and University of Toronto Room 4W 449 399 Bathurst Street Toronto Ontario M5T 2S8 Canada Abstract Although cervical spondylotic myelopathy is a common cause of chronic spinal cord dysfunction in humans little is known about the molecular mechanisms underlying the progressive neural degeneration characterized by this condition Based on animal models of cervical spondylotic myelopathy and traumatic spinal cord injury we hypothesized that Fas mediated apoptosis and inflammation may play an important role in the pathobiology of human cervical spondylotic myelopathy We further hypothesized that neutralization of the Fas ligand using a function blocking antibody would reduce cell death attenuate inflammation promote axonal repair and enhance functional neurological outcomes in animal models of cervical spondylotic myelopathy We examined molecular changes in post mortem human spinal cord tissue from eight patients with cervical spondylotic myelopathy and four control cases Complementary studies were conducted using a mouse model of cervical spondylotic myelopathy twy twy mice that develop spontaneous cord compression at C2 C3 We observed Fas mediated apoptosis of neurons and oligodendrocytes and an increase in inflammatory cells in the compressed spinal cords of patients with cervical spondylotic myelopathy Furthermore neutralization of Fas ligand with a function blocking antibody in twy twy mice reduced neural inflammation at the lesion mediated by macrophages and activated microglia glial scar formation and caspase 9 activation It was also associated with increased expression of Bcl 2 and promoted dramatic functional neurological recovery Our data demonstrate for the first time in humans the potential contribution of Fas mediated cell death and inflammation to the pathobiology of cervical spondylotic myelopathy Complementary data in a murine model of cervical spondylotic myelopathy further suggest that targeting the Fas death receptor pathway is a viable neuroprotective strategy to attenuate neural degeneration and optimize neurological recovery in cervical spondylotic myelopathy Our findings highlight the possibility of medical treatments for cervical spondylotic myelopathy that are complementary to surgical decompression Spinal cord injury induced astrocyte migration and glial scar formation effects of magnetic stimulation frequency Li Z Fang ZY Xiong L Huang XL Source Department of Rehabilitation Medicine WHO Collaborating Centre for Training and Research in Rehabilitaion CHN 60 Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Abstract The effects of magnetic stimulation on spinal cord injury induced migration of white matter astrocytes were studied using an established animal model Ethidium bromide was injected into the dorsal spinal cord funiculus of adult Sprague Dawley rats on the left side at T10 11 Animals then received 1 52 Tesla pulsed magnetic stimulation for 5 min at different frequencies 0 20 Hz for 14 consecutive days Selected animals received the non competitive MEK1 2 inhibitor U0126 10 microM prior to stimulation at 10 Hz Lesion volumes were measured in hematoxylin eosin stained sections Expression of glial fibrillary acidic protein GFAP microtubule associated protein 2 MAP 2 and extra cellular signal regulated kinasel 2 ERK1 2 near the epicenter of injury was examined by Western blotting with quantification using an image analysis system Lesion volumes decreased and GFAP and p ERK1 2 expression increased with increasing magnetic stimulation frequency 0 10 Hz MAP 2 expression was not affected at any frequency Pretreatment with U0126 reduced GFAP and ERK1 2 expression and increased lesion volumes in response to stimulation at 10 Hz It is concluded that magnetic stimulation increases the migration of astrocytes to spinal cord lesions Activation of the ERK1 2 signaling pathway is proposed to mediate astrocyte migration and glial scar formation in response to spinal cord injury Transplantation of human glial restricted progenitors and derived astrocytes into a contusion model of spinal cord injury Jin Y Neuhuber B Singh A Bouyer J Lepore A Bonner J Himes T Campanelli JT Fischer I Source Department of Neurobiology and Anatomy Drexel University College of Medicine Philadelphia Pennsylvania 19129 USA Abstract Transplantation of neural progenitors remains a promising therapeutic approach to spinal cord injury SCI but the anatomical and functional evaluation of their effects is complex particularly when using human cells We investigated the outcome of transplanting human glial restricted progenitors hGRP and astrocytes derived from hGRP hGDA in spinal cord contusion with respect to cell fate and host response using athymic rats to circumvent xenograft immune issues Nine days after injury hGRP hGDA or medium were injected into the lesion center and rostral and caudal to the lesion followed by behavioral testing for 8 weeks Both hGRP and hGDA showed robust graft survival and extensive migration The total number of cells increased 3 5 fold for hGRP and twofold for hGDA indicating graft expansion but few proliferating cells remained by 8 weeks Grafted cells differentiated into glia predominantly astrocytes and few remained at progenitor state About 80 of grafted cells around the injury were glial fibrillary acidic protein GFAP positive gradually decreasing to 40 50 at a distance of 6 mm Conversely there were few graft derived oligodendrocytes at the lesion but their numbers increased away from the injury to 30 40 Both cell grafts reduced cyst and scar formation at the injury site compared to controls Microglia macrophages were present at and around the lesion area and axons grew along the spared tissue with no differences among groups There were no significant improvements in motor function recovery as measured by the Basso Beattie and Bresnahan BBB scale and grid tests in all experimental groups Cystometry revealed that hGRP grafts attenuated hyperactive bladder reflexes Importantly there was no increased sensory or tactile sensitivity associated with pain and the hGDA group showed sensory function returning to normal Although the improved lesion environment was not sufficient for robust functional recovery the permissive properties and lack of sensory hypersensitivity indicate that human GRP and astrocytes remain promising candidates for therapy after SCI PMID 21222572 PubMed indexed for MEDLINE PMCID PMC3070147 Available on 2012 4 1 Interaction of olfactory ensheathing cells with other cell types in vitro and after transplantation glial scars and inflammation Chuah MI Hale DM West AK Source Menzies Research Institute University of Tasmania Hobart 7001 Australia Inn Chuah utas edu au Abstract Olfactory ensheathing cells OECs have been investigated extensively as a therapy to promote repair in the injured CNS with variable efficacy in numerous studies over the previous decade In many studies that report anatomical and functional recovery the beneficial effects have been attributed to the ability of OECs to cross the PNS CNS boundary their production of growth factors cell adhesion molecules and extracellular matrix proteins that promote and guide axon growth and their ability to remyelinate axons In this brief review we focus on the interaction between OECs and astrocytes in vivo and in vitro in the context of how OECs may be overcoming the deleterious effects of the glial scar Drawing from a selection of different experimental models of spinal injury we discuss the morphological alterations of the glial scar associated with OEC transplants and the in vitro research that has begun to elucidate the interaction between OECs and the cell types that compose the glial scar We also discuss recent research showing that OECs bear properties of immune cells and the consequent implication that they may modulate neuroinflammation when transplanted into CNS injury sites Future studies in unraveling the molecular interaction between OECs and other glial cells may help explain some of the variability in outcomes when OECs are used as transplants in CNS injury and more importantly contribute to the optimization of OECs as a cell based therapy for CNS injury This article is part of a Special Issue entitled Understanding olfactory ensheathing glia and their prospect for nervous system repair Copyright 2010 Elsevier Inc All rights reserved Spinal cord injury induces different