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1.
We have established a permanent cell line (CG-4) of rat central nervous system glial precursors from primary cultures of bipotential oligodendrocyte-type 2-astrocyte (O-2A) progenitor cells, which were kept proliferating with the mitogen(s) secreted by the neuronal B104 cell line. The CG-4 cells have a normal karyotype and display the properties of normal O-2A cells. CG-4 cells can be propagated in serum-free culture medium supplemented with medium conditioned by B104 cells for unrestricted periods of time as O-2A cells, characterized by the presence of the A2B5 surface marker and the absence of markers specific for oligodendrocytes (galactocerebroside, myelin basic protein) or type 2-astrocytes (glial acidic fibrillary protein). bFGF and PDGF are potent mitogens for CG-4 cells and their combination can substitute for the B104-derived mitogen(s). CG-4 cells are capable of differentiating into either oligodendrocytes or type 2-astrocytes. Differentiation into oligodendrocytes occurs after withdrawal of the mitogen. Replacement of the mitogen with fetal calf serum (20%), in contrast, induces 50% of the CG-4 cells to differentiate into type 2-astrocytes. Pure cultures of oligodendrocytes or type 2-astrocytes can be generated in substantial amounts from CG-4 cells and maintained for several weeks in medium containing 5% fetal calf serum.  相似文献   

2.
In this study we used as glial cell models, early and late passage C-6 glial cells, 2B clone, and advanced passages of glial cells derived from aged mouse cerebral hemispheres (MACH) to examine responsiveness to opioids. We have previously reported that early passage C-6 glial cells, 2B clone, are bipotential and can be geared toward oligodendrocyte or astrocytic expression, whereas late passage C-6 glial cells are astrocytic. In addition, MACH cultures have been previously characterized and consist of astrocytes type 1 and 2, some oligodendrocytes, and few glial precursors. In this study, early passage (17–20) and late passage (106–108) C-6 glial cells or MACH cells of passages 16–19 were grown from plating time until harvesting, day 7 or 8, in DMEM + 10% FBS in the presence or absence of opioid peptides, Leu-enkephalin (10?8 to 10?10 M) or its synthetic analog, dalargin (Tyr-D-Ala-Gly-Phe-Leu-Arg; 10?8 to 10?10 M). We examined for the activities of glutamine synthetase (GS) and cyclic nucleotide phosphohydrolase (CNP), enzyme markers for astrocytes and oligodendrocytes, respectively. We found that CNP activity was markedly increased in the early passage following opioid treatment, indicative of a shift to oligodendrocytic expression. In the late passage cells, already committed to astrocytic expression, opioid treatment enhanced GS activity suggesting that astrocytes respond to opioids. GS activity was markedly increased in MACH cultures grown in the presence of opioids with no changes in CNP. Thus, type 1 astrocytes, the predominant glial type in MACH cultures, responded to opioids. We conclude from these findings derived from two different glial models that regulation of astrocytes by microenvironmental signals appears to be maintained with aging. © 1993 Wiley-Liss, Inc.  相似文献   

3.
Dioxin is suspected to cause adverse effects on the development of the central nervous system (CNS). To investigate the neurotoxic effects of dioxin on the differentiation of astrocytes, rat C6 glial cell line was used as a model, because these cells are induced to express astrocyte markers and to change the cell morphology toward an astrocytic phenotype by increasing intracellular cAMP levels. When C6 cells were simultaneously exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and N(6),O(2')-dibutylyl cAMP (dbcAMP), the expression of cytochrome P-450 1A1 (CYP1A1) was dramatically increased, and the expression of aryl hydrocarbon receptor (AhR) was moderately decreased in a dose-dependent manner. In addition, extension of astrocytic processes was inhibited by 1 nM TCDD that did not reduce cell viability. TCDD also inhibited the induction of glial fibrillary acidic protein (GFAP) expression in a dose-dependent manner, until the end of a 72-hr exposure period. This inhibition was restored by the addition of an antagonist of AhR, alpha-naphthoflavone. These results indicate that TCDD inhibits astrocytic differentiation of C6 cells, which may be mediated by an AhR-dependent pathway.  相似文献   

4.
5.
An immortalized clonal cell line (AP-16) has been established from glial cultures obtained from neonatal mouse cerebra by multipassages under serum-free conditions. Immunofluorescent experiments showed that AP-16 cells expressed a marker for glial progenitors (A2B5) and did not express markers for oligodendrocytes (galactocerebroside) or mature astrocytes (glial fibrillary acidic protein: GFAP). Treatment with transforming growth factor-β1 (TGF-β1) or fetal calf serum (FCS) for 2 days induced AP-16 cells to differentiate into A2B5-negative, GFAP-positive, phenotypically mature astrocytes. AP-16 cells depended on epidermal growth factor for survival, and their growth was inhibited by FCS. These results indicate that AP-16 cells retained the properties of astrocyte progenitors. An enzyme-linked immunosorbent assay showed that AP-16 cells synthesized fibronectin and laminin, and that the expression of fibronectin was increased by TGF-β1. AP-16 cells should be useful for studying the roles of TGF-β1 in the differentiation of astrocyte progenitors. © 1993 Wiley-Liss, Inc.  相似文献   

6.
Cell interactions in the nervous system are frequently mediated by surface proteins that are attached to the membrane by a glycosyl phosphatidylinositol (GPI) anchor. In this study, we have characterized the expression of such proteins on glial cells. We have detected a major GPI-anchored protein on astrocytes and Schwann cells, with a molecular weight of 140 kD. When Schwann cells were treated with forskolin to promote a myelinating phenotype, expression of this 140-kD protein dramatically decreased, whereas another GPI-anchored protein of 80 kD was strongly induced; expression of other integral membrane proteins were likewise dramatically altered. The size and pattern of expression of the 140-kD protein suggested that it might correspond to the Ran-2 antigen, a glial lineage marker. This notion was confirmed by immunoprecipitating this 140-kD protein with the Ran-2 monoclonal antibody. The Ran-2 antigen is expressed over the entire Schwann cell surface in a punctate fashion; it is removed by phosphatidylinositol phospholipase C treatment, thereby confirming that it is GPI-anchored. When Schwann cells are cocultured with neurons, the Ran-2 antigen initially concentrates at sites of Schwann cell contact with neurons, suggesting that it may play a role in early Schwann cell–neuron interactions; it is then downregulated. Protein sequencing of the Ran-2 antigen immunopurified from rat brain membranes showed complete identity over two extended segments with the copper binding protein ceruloplasmin. These findings indicate that astrocytes and Schwann cells express a novel GPI-anchored form of ceruloplasmin and suggest that this GPI form plays a role in axonal–glial interactions. J. Neurosci. Res. 54:147–157, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

7.
Adult mesenchymal stem cells (MSCs) exhibit neuroprotective properties when introduced into the degenerating central nervous system through different putative mechanisms including secretion of growth factors and transdifferentiation. In the present study, we injected MSCs into the cerebrospinal fluid of symptomatic hSOD1G93A rats, a transgenic animal model of familial amyotrophic lateral sclerosis (ALS) expressing a mutated form of the human superoxide dismutase. MSCs were found to infiltrate the nervous parenchyma and migrate substantially into the ventral gray matter, where motor neurons degenerate. Even though overall astrogliosis was not modified, MSCs differentiated massively into astrocytes at the site of degeneration. The intrathecal delivery of MSCs and the subsequent generation of healthy astrocytes at symptomatic stage decreased motor neuron loss in the lumbar spinal cord, preserving motor functions and extending the survival of hSOD1G93A rats. This neuroprotection was correlated with decreased inflammation, as shown by the lower proliferation of microglial cells and the reduced expressiontion of COX‐2 and NOX‐2. Together, these data highlight the protective capacity of adult MSC‐derived astrocytes when grafted into the central nervous system and illustrate an attractive strategy to target excessive inflammation in ALS. © 2009 Wiley‐Liss, Inc.  相似文献   

8.
Neuronal differentiation is influenced by extracellular factors; however, only a few such factors have been identified for central neurons. To address this issue, we have screened media conditioned (CM) by several glial cell lines for neurotrophic effects on dopaminergic neurons in dissociated cell cultures of the E14.5 rat mesencephalon grown in serum-free conditions. To establish culture conditions under which dopaminergic cell survival depends on the exogenous support from neurotrophic factors, cell suspensions were seeded at varying densities and the number of tyrosine hydroxylase-immunoreactive (TH-IR) neurons was determined. This number was maximal at plating densities greater than 175,000 cells/cm2 and was 10-fold lower at the plating density of 80,000 cells/cm2. Cell density had only a minimal effect on [3H]dopamine uptake per TH-IR neuron. Treatment of cultures plated at 80,000 cells/cm2 with CM derived from the glial cell line, B49, the neural retina glial cell line, R33, and the Schwannoma cell line JS1, increased the number of surviving TH-IR neurons 160-330%. These effects were dose dependent and heat sensitive. All CM stimulated neurite elongation of TH-IR neurons, while only the B49-CM increased [3H]dopamine uptake. The neurotrophic effects of these media were not confined to dopaminergic neurons but increased overall neuronal density in culture by 50-100%. Moreover, all three CM were mitogenic for mesencephalic glia as demonstrated by glial fibrillary acidic protein (GFAP)-immunocytochemistry in combination with [3H]thymidine-autoradiography. By contrast, medium conditioned by the pheochromocytoma cell line, PC12, did not increase the number of astrocytes or promote the survival of dopaminergic neurons. Inhibition of glial proliferation reduced the neurotrophic effects of the B49-, R33-, and JS1-CM by 40-80%. These observations suggest that the glial cell lines B49, R33, and JS1 secrete factors that promote the survival of dopaminergic neurons and induce proliferation of glial precursors. The partial decrease of the survival-promoting effects of these CM on dopaminergic neurons in glial-free mesencephalic cultures further suggests that the observed neurotrophic effects result from the combined action of cell line-derived substances directly on neurons and indirectly via effects on mesencephalic astrocytes or astrocyte precursors.  相似文献   

9.
We have investigated the phenotypic and bioassay characteristics of bone marrow mesenchymal stromal cells (MSCs) differentiated along a Schwann cell lineage using glial growth factor. Expression of the Schwann cell markers S100, P75, and GFAP was determined by immunocytochemical staining and Western blotting. The levels of the stem cell markers Stro-1 and alkaline phosphatase and the neural progenitor marker nestin were also examined throughout the differentiation process. The phenotypic properties of cells differentiated at different passages were also compared. In addition to a phenotypic characterization, the functional ability of differentiated MSCs has been investigated employing a co-culture bioassay with dissociated primary sensory neurons. Following differentiation, MSCs underwent morphological changes similar to those of cultured Schwann cells and stained positively for all three Schwann cell markers. Quantitative Western blot analysis showed that the levels of S100 and P75 protein were significantly elevated upon differentiation. Differentiated MSCs were also found to enhance neurite outgrowth in co-culture with sensory neurons to a level equivalent or superior to that produced by Schwann cells. These findings support the assertion that MSCs can be differentiated into cells that are Schwann cell-like in terms of both phenotype and function.  相似文献   

10.
Lactate is an important metabolic substrate for the brain during the postnatal period and also plays a crucial role in the traffic of metabolites between astrocytes and neurons. However, to date there are no clues with regard to lactate utilization by oligodendrocytes, the myelin-forming cells in the brain. In the present work, lactate utilization by oligodendrocytes in culture was investigated and compared with its utilization by cultured neurons, type 1 and type 2 astrocytes. Our results clearly indicate that oligodendrocytes readily use lactate both as a metabolic fuel and as a precursor to build carbon skeletons. Oligodendrocytes oxidize lactate at a higher rate than that observed for neurons and astrocytes, and their rate of lipid synthesis from lactate was at least 6-fold higher than that found in astrocytes or neurons. The rate of glucose utilization through different pathways was also investigated. The flux of glucose through the pentose phosphate pathway and the rate of lipid synthesis were at least 2-fold higher in oligodendrocytes than in astrocytes or neurons. These findings indicate that oligodendrocyte metabolism is designed specifically for the synthesis of lipids, presumably those of myelin.  相似文献   

11.
A number of cytokines and growth factors may affect astrocyte proliferation and functions. Transforming growth factor-β1 (TGF-β1) is a pleiotropic cytokine which exerts multiple effects on growth and differentiation of different cell types. TGF-β1 is present in low amounts in the normal brain. TGF-β1 gene expression, however, is increased in the central nervous system (CNS) in several pathological conditions. In this study we examined the in vitro effects of TGF-β1 on the proliferative response of rat astrocytes to serum and growth factors. Astrocyte cultures were established from the cerebellum and cortex of newborn Lewis rats. The proliferative response of these cultures to serum and growth factors [platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin-like growth factor 1 (IGF-1), IGF-2, interleukin 1 (IL-1)] was studied by [3H]-thymidine incorporation test in the presence or absence of TGF-β1. TGF-β1 significantly inhibited the proliferative response of astrocyte cultures to both autologous and heterologous serum. In addition, a strong inhibition of bFGF-, EGF-, and PDGF-induced proliferation was observed. The effect of TGF-β1 on the proliferative response to IL-1 was less evident but still significant. No effect was observed when TGF-β1 was added to IGF-1 and IGF-2 stimulated cultures. These data confirm previous reports showing a down-regulating activity of TGF-β on astrocyte proliferation and suggest that this cytokine may play physiological and pharmacological roles in the regulation of reactive astrocytosis in the CNS. © 1995 Wiley-Liss, Inc.  相似文献   

12.
Injury to the adult brain results in abortive axon regeneration and the deposition of a dense fibrous glial scar. Therapeutic strategies to promote postinjury axon regeneration are likely to require antiscarring strategies. In neonatal brain wounds, scar material is not laid down and axons grow across the lesion site, either by de novo growth or regeneration. To achieve the therapeutic goal of recapitulating the nonscarring neonatal response in the injured adult, an understanding of how ontogenic differences in scarring reflect developmental diversities in the trophic response to injury is required. Fibrobast growth factor-2 (FGF-2) expression is developmentally regulated and has been implicated as a regulator of the wounding response of the adult rat central nervous system. We have investigated the expression of FGF-2 and fibroblast growth factor receptor 1 (FGFR1) after penetrating lesions to the cerebral cortex of 5 days post partum (dpp) (nonscarring) and 16 dpp and adult (scarring) rats. In situ hybridization, immunohistochemistry and Western blotting showed robust and sustained increases in FGF-2 and FGFR1 mRNA and protein in reactive astrocytes around the lesion in scarring rats, a response that was attenuated substantially in the nonscarring neonate. These results demonstrate that changes in astrocyte FGF-2 and FGFR1 expression are coincident with the establishment of a mature pattern of glial scarring after injury in the maturing central nervous system, but it is premature to infer a causal relationship without further experiments.  相似文献   

13.
In the mammalian central nervous system (CNS), multipotential neural stem cells in the neuroepithelium generate the three major types of neural cells, namely, neurons, astrocytes, and oligodendrocytes. To explore the molecular mechanisms underlying proliferation and differentiation of these neural stem cells, we established a cell line named MNS-57 from the embryonic day 12 rat neuroepithelium by introducing the mycer fusion gene, in which c-myc can be conditionally activated by adding oestrogen to the culture medium. MNS-57 cells expressed nestin, vimentin, and the RC1 antigen, which are potential markers for neural stem cells. We show that under particular culture conditions, MNS-57 cells can conditionally generate neurons, astrocytes, and oligodendrocytes in vitro, indicating that they are likely to originate from multipotential neural stem cells. Incubating MNS-57 cells with either oestrogen, which activates mycer, or growth factors such as basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) stimulated their growth, and the combination of oestrogen and bFGF (or EGF) had a synergistically stronger mitogenic effect than the single factors. Furthermore, both c-myc activation and bFGF appeared to be necessary for the differentiation of MNS-57 cells, and only when stimulated by both signals simultaneously, the cells committed to generating multiple neural cell types. Thus, the property of the cell line is unique in that its differentiation into neurons and glia can be conditionally manipulated invitro in an exogenous signal-dependent manner. We propose that the cell line described here will provide an useful in vitro model to understand genetic and environmental mechanisms that control the generation of neural cell diversity in the CNS. © 1995 Wiley-Liss, Inc.  相似文献   

14.
Transplantation of glial cells into the central nervous system (CNS) may be a promising approach for the treatment of myelin disorders such as multiple sclerosis (MS). Myelination by transplantation of oligodendrocyte precursors has been obtained in different animal models of demyelination. A strategy to favor CNS remyelination is to enrich the lesioned areas in growth factors to stimulate the quiescent population of oligodendrocyte precursors. In this context, we have developed a genetically modified CG4 cell line (CG4-FGF2), which are able to release significant amounts of fibroblast growth factor 2 (FGF2) in a controlable fashion in vitro. The data presented here demonstrate that upon induction with Dox, CG4-FGF2 cells retain their capacity to differentiate in vitro. Additionally, we provide evidence that FGF2 release by engineered cells enhance proliferation and migration of cells of the oligodendrocyte lineage without preventing them to differentiate and myelinate axons in vitro.  相似文献   

15.
目的建立稳定转染ndrg2基因的脑胶质瘤细胞系,以探索及研究该基因的功能。方法以低表达ndrg2基因的脑胶质瘤细胞系U251为材料,以ndrg2基因转染U251细胞系,经G418进行筛选后,挑取单克隆进行培养,用荧光显微镜观察、逆转录酶聚合酶链反应(RT—PCR)验证获得的表达细胞株。结果经转染和G418筛选后,荧光显微镜下见有明显表达ndrg2基因的细胞约占70%-80%,RT-PCR检测到转染基因ndrg2后细胞ndrg2的高表达,而转染空载体的细胞ndrg2低表达。结论成功建立了稳定转染基因ndrg2的脑胶质瘤细胞系U251,为进一步探讨该基因的功能奠定了一定基础。  相似文献   

16.
Peripheral nerve injury leads to the activation of spinal cord astrocytes, which contribute to maintaining neuropathic (NP) pain behavior. Fibroblast growth factor-2 (FGF-2), a neurotrophic and gliogenic factor, is upregulated by spinal cord astrocytes in response to ligation of spinal nerves L5 and L6 (spinal nerve ligation [SpNL]). To evaluate the contribution of spinal astroglial FGF-2 to mechanical allodynia following SpNL, neutralizing antibodies to FGF-2 were injected intrathecally. Administration of 18 μg of anti-FGF-2 antibodies attenuated mechanical allodynia at day 21 after SpNL and reduced FGF-2 and glial acidic fibrillary protein mRNA expression and immunoreactivity in the L5 spinal cord segment of rats with SpNL. These results suggest that endogenous astroglial FGF-2 contributes to maintaining NP tactile allodynia associated with reactivity of spinal cord astrocytes and that inhibition of spinal FGF-2 ameliorates NP pain signs.  相似文献   

17.
ATP is an important signaling molecule in the nervous system and it's signaling is mediated through the metabotropic P2Y and ionotropic P2X receptors. ATP is known to stimulate Ca(2+) influx and phospholipase D (PLD) activity in the type-2 astrocyte cell line, RBA-2; in this study, we show that the release of preloaded [(3)H]GABA from RBA-2 cells is mediated through the P2X(7) receptors. ATP and the ATP analogue 3'-O-(4-benoylbenoyl)-adenosine-5'-triphosphate (BzATP) both stimulated [(3)H]GABA release in a concentration dependent manner, while the nonselective P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), the P2X(7)-sensitive antagonist oxidized ATP (oATP), and high extracellular Mg(2+) all inhibited the ATP-stimulated [(3)H]GABA release. The ATP-stimulated [(3)H]GABA release was not affected neither by removing extracellular Na(+) nor by changes in the intracellular or extracellular Ca(2+) concentration. The GABA transporter inhibitors nipecotic acid and beta-alanine also had no effect. The ATP-stimulated [(3)H]GABA release was blocked, however, when media Cl(-) was replaced with gluconate and when extracellular HCO(3)(-) was removed. The Cl(-) channel/exchanger blockers 4,4'-diisothiocyanatostilbene-2',2'-disulfonic acid (DIDS) and 4-acetamido-4'- isothiocyanatostilbene-2',2'-disulfonic acids (SITS), but not diphenylamine-2-carboxylic acid (DPC) and furosemide, blocked the ATP-stimulated [(3)H]GABA release. The anionic selectivity of the process was F(-) > Cl(-) > Br(-) which is the same as that reported for volume-sensitive Cl(-) conductance. Treating cells with phorbol-12-myristate 13-acetate (PMA), forskolin, dibutyryl-cAMP, PD98059, neomycin, and D609 all inhibited the ATP-stimulated [(3)H]GABA release. We concluded that in RBA-2 cells, ATP stimulates [(3)H]GABA release through the P2X(7) receptors via a Cl(-)/HCO(3)(-)-dependent mechanism that is regulated by PKC, PKA, MEK/ERK, and PLD.  相似文献   

18.
Shetty AK  Hattiangady B  Shetty GA 《Glia》2005,51(3):173-186
Dentate neurogenesis, important for learning and memory, declines dramatically by middle age. Although studies have shown that this age-related decrease can be reversed to some extent by exogenous applications of mitogenic factors, it is unclear whether one or more of these factors exhibits decline by middle age. We hypothesize that multiple stem/progenitor cell proliferation factors exhibit early decline during the course of aging in the hippocampus, and some of these declines are linked to age-related alterations in hippocampal astrocytes. We measured the concentrations of fibroblast growth factor-2 (FGF-2), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF) in the hippocampus of young, middle-aged, and aged F344 rats, using enzyme-linked immunosorbent assay (ELISA). In addition, we quantified the total number of FGF-2 immunopositive (FGF-2+) and glial fibrillary acidic protein immunopositive (GFAP+) cells in the dentate gyrus and the entire hippocampus. Our results provide new evidence that the concentrations of FGF-2, IGF-1, and VEGF decline considerably by middle age but remain steady between middle age and old age. Further, decreased concentrations of FGF-2 during aging are associated with decreased numbers of FGF-2+ astrocytes. Quantification of GFAP+ cells, and GFAP and FGF-2 dual immunostaining analyses, reveal that aging does not decrease the total number of astrocytes but fractions of astrocytes that express FGF-2 decline considerably by middle age. Thus, dramatically decreased dentate neurogenesis by middle age is likely linked to reduced concentrations of FGF-2, IGF-1, and VEGF in the hippocampus, as each of these factors can individually influence the proliferation of stem/progenitor cells in the dentate gyrus. Additionally, the results demonstrate that decreased FGF-2 concentration during aging is a consequence of age-related impairment in FGF-2 synthesis by astrocytes.  相似文献   

19.
The transforming growth factor-betas (TGF-betas) are potent fibrogenic factors implicated in numerous central nervous system (CNS) pathologies in which fibrosis and neural dysfunction are causally associated. In this study, we aim to limit the fibrogenic process in a model of CNS scarring using a recombinant human monoclonal antibody, derived from phage display libraries and specific to the active form of the TGF-beta2 isoform. The implicit inference of the work was that, as such antibodies are potential pharmacological agents for the treatment of human CNS fibrotic diseases, validation of efficacy in a mammalian animal model is a first step towards this end. Treatment of cerebral wounds with the anti-TGF-beta2 antibody led to a marked attenuation of all aspects of CNS scarring, including matrix deposition, formation of an accessory glial-limiting membrane, inflammation and angiogenesis. For example, in the wound, levels of: (i) the connective tissue components fibronectin, laminin and chondroitin sulphate proteoglycan; and (ii) wound-responsive cells including astrocytes and macrophages/microglia, were markedly reduced. Our findings suggest that such synthetic anti-fibrotic TGF-beta antibodies are potentially applicable to a number of human CNS fibrotic diseases to arrest the deposition of excessive extracellular matrix components, and maintain and/or restore functional integrity.  相似文献   

20.
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