摘要:

AbstractNucleoside diphosphatase (NDP‐ase) labelled microglial cells were examined in retinas of three strains of rabbit, the New Zealand White (albino), the Canberra Half‐Lop, and the Dutch Belted. The distribution in the nerve fibre and inner plexiform layers was similar in all strains. However, the outer plexiform layer (OPL) of Dutch‐Belted rabbits was completely covered with a population of non‐overlapping NDP‐ase positive microglia while the OPL of New Zealand White and Half‐Lop strains contained only occasional isolated cells. In the Dutch‐Belted strain the area covered by the processes of each cell was less in central than peripheral retina where the cell density was lower. In the central retina of the New Zealand White and Half‐Lop strains the cells covered an area similar to that of peripheral Dutch‐Belted cells, suggesting that they were at a low density and there was no hidden population of cells. This finding was confirmed by Griffonia simplicifolia lectin labelling. Therefore the data is consistent with there being a strain variation in OPL microglia. The intensity of NDP‐ase label in the IPL and GCL was less in the New Zealand White and Half‐Lop strains and although the intensity increased after retinal injury it never reached that of the Dutch‐Belted retinas. These variations in the intensity of NDP‐ase expression and the localization of microglial cells may be important in inflammation and also for CNS functio

ISSN:0894-1491    

DOI:10.1002/glia.440150402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAdhesion molecule on glia (AMOG) represents the β2‐subunit of murine Na, K‐ATPase. Mice carrying a targeted deletion of the AMOG/β2 gene exhibit tremor and limb paralysis at postnatal day (P) 15 and die 2 days after the onset of symptoms. The brains of these mice show edema and swelling of astrocytic end feet However, the cause of death has remained unclear. To identify long‐term consequences of AMOG/β2 deficiency, we have grafted parts of the embryonic telencephalic anlage of AMOG/β2deficient mice into the caudoputamen of wild‐type mice and analyzed the grafts up to 500 days after transplantation. Histological, immunocytochemical, and in situ hybridization techniques were applied to examine histoarchitecture, proliferation, differentiation, and long‐term survival of grafts.AMOG/β2‐deficient telencephalic grafts develop normally and form solid neural tissue that cannot be distinguished from control grafts by morphological features or with immunocytochemical stains for neuronal and glial markers. No signs of degeneration can be found. Expression analysis, however, revealed that no AMOG/β2 protein of possible host origin can be detected in AMOG/β2‐deficient grafts. Graft‐borne astrocytes express neither the AMOG/β1 nor the AMOG/β2 subunit of Na, K‐ATPase as examined with immunocytochemistry and in situ hybridization. These findings indicate that AMOG/β2 is not necessary for loner‐term survival of telenceohalic eraft t

ISSN:0894-1491    

DOI:10.1002/glia.440150403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractMonoclonal antibody 3CB2 recognizes an antigen expressed in discrete cell types derived from ectoderm and mesoderm. Biochemical and immunohistochemical studies indicate that the antigen recognized by the antibody is a 55 kDa cytoplasmic protein that may be an intermediate filament associated protein (IFAP). Developmental studies show that 3CB2 antigen is intensely expressed very early in the chick embryo, in the neural tube, myotomes, and in mesenchymal cells of visceral arches and the presumptive facial area. As development proceeds, antigen expression becomes restricted to astrocytes and radial glia cells throughout the brain.A detailed immunohistochemical study of the developing chick retina shows that the expression of 3CB2 antigen at embryonic day 8 (E8) is restricted to Müller cells, with the pattern of expression closely related to their degree of differentiation. We show, by immunocytochemistry labeling of entire Müller cells dissociated from retinas of E16‐E20, that 3CB2 monoclonal is labeling the whole cell. 3CB2 selectively labels Müller cells in the rat and chameleon, but not their retinal horizontal cell axons.3CB2 monoclonal is a very sensitive marker for early differentiating Müller cells. Our results provide evidence that 3CB2 antigen is a cytoskeletal component which may be involved in the morphogenesis of these cells, and also perhaps in the outgrowth of some axons. © 1995 Wiley‐L

ISSN:0894-1491    

DOI:10.1002/glia.440150404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractNeural cells are classically identified in vivo and in vitro by a combination of morphological and immunocytochemical criteria. Here, we demonstrate that antibodies used to identify mammalian oligodendrocytes, neurons, and astrocytes recognize these cell types in the developing spiny dogfish central nervous system and in cultures prepared from this tissue. Oligodendrocyte‐lineage‐specific antibodies O1, O4, and R‐mAb labeled cells in the 9 cm dogfish brain stem's medial longitudinal fascicle (MLF) and in areas lateral to it. Process‐bearing cells, cultured from the dogfish brain stem, were also labeled with these antibodies. An anti‐lamprey neurofilament antibody (LCM), which recognized 60 and 150 kDa proteins in dogfish brain stem homogenates, labeled axons and neurons in the brain stem and axons in the cerebellum of the dogfish embryo. It also labeled cell bodies and/or processes of some cultured cerebellar cells. An anti‐bovine glial fibrillary acidic protein antibody, which recognized 42–44 kDa protein(s) in dogfish brain stem homogenates, labeled astrocyte‐like processes in the brain stem and cerebellum of the dogfish embryo and numerous large and small flat cells in the cerebellar cultures. These results demonstrate that dogfish oligodendrocytes, neurons, and astrocytes express antigens that are conserved in mammalian neural cells. The ability to culture and identify neural cell types from cartilaginous fish sets the stage for studies to determine if proliferation, migration, and differentiation of these cell types are regulated in a similar fashion to mammalian cells. © 1995

ISSN:0894-1491    

DOI:10.1002/glia.440150405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have examined both how the molecular phenotype of Schwann cells in vitro is regulated by transforming growth factor β (TGF‐β), using immunohistochemistry and immunoblotting, and the distribution of TGF‐β2 and 3 in embryonic and mature nerves and ganglia, using immunohistochemistry and in situ hybridisation. We find that TGF‐β2 and ‐3 upregulate expression of the neural cell adhesion molecules NCAM and L1. In TGF‐β‐treated cultures, in addition to the 140 and 120 kD isoforms known to be present in Schwann cells, small amounts of the 180 kD isoform can be detected. TGF‐βs also block cAMP‐induced expression of the lipid antigens galactocerebroside (GalC) and O4, in addition to blocking expression of protein zero (P0), the major peripheral myelin glycoprotein, as previously shown.Using antibodies specific to TGF‐β2 and −3, respectively, we confirm the presence of these proteins in myelin‐forming Schwann cells and show also that TGF‐β2 and −3 are clearly expressed by peripheral glia that are not involved in myelination. This includes Schwann cell precursors, embryonic Schwann cells, non‐myelin‐forming Schwann cells and satellite cells from adult nerves and ganglia, and neonatal Schwann cells in purified cultures without neurones. In situ hybridisation with a digoxygenin‐labelled riboprobe reveals a strong TGF‐β3 mRNA signal in Schwann cells, satellite cells, and some neurones. Schwann cells in culture also secrete TGF‐β in a latent form, whereas purified cultures of dorsal root ganglion neurones from 1‐day‐old rats secrete active TGFß during

ISSN:0894-1491    

DOI:10.1002/glia.440150406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractClinical signs of experimental autoimmune encephalomyelitis (EAE) in rats can be suppressed by treatment with liposomes containing dichloromethylene diphosphonate (Cl2MDP liposomes). Here we investigated whether besides the blood‐borne macrophages also ED2+perivascular cells and microglia are affected by this treatment. For this purpose we examined the central nervous system of bone marrow chimeras in which EAE was induced with encephalitogenic T cells. Quantification of cell numbers of various cell types in inflammatory lesions in the spinal cord showed that after treatment with Cl2MDP liposomes more than 95% of the bone marrow derived (I1‐69+) macrophages were eliminated. In addition the number of ED2+perivascular cells were seen to be decreased by 68% as compared to ED2+cells in control liposome treated animals. However the number of these perivascular cells in Cl2MDP liposome treated animals did not differ from the number of perivascular cells in naive animals, indicating that only newly recruited, inflammation associated, ED2+macrophages were eliminated. Moreover, detection of degenerating nuclei by in situ nick translation (ISNT) in combination with staining for ED1 or ED2 showed that in the perivascular space no degenerating cells were present. Cl2MDP liposome treatment furthermore decreased the numbers of T cells infiltrating the parenchyma by more than 50%. Instead T cells were found in large numbers in the perivascular space. Microglia did not seem to be eliminated by Cl2MDP liposome treatment as shown by the absence of ED1+/ISNT+cells in the CNS parenchyma. However the number of ED1+(I1‐69−) microglial cells decreased by more than 80%, indicating that the activation of this cell type was impaired. It is concluded that bone marrow derived macrophages play an important role in the pathogenesis of EAE via interactions with lymphocytes and the activation of resident microglia. © 1995 Wiley

ISSN:0894-1491    

DOI:10.1002/glia.440150407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractFactors affecting gene expression in microglial cells were investigated using the induction of immediate early genes in cultured microglia as a model. In particular, the actions of calcitonin gene‐related peptide (CGRP) and ATP, both of which have been proposed as signalling molecules in the activation of glial cells, were evaluated using Northern blotting and in situ hybridization methods. In the presence of CGRP, c‐fos and junB mRNAs accumulated in microglial cultures, whereas no significant change in c‐jun and TIS11 mRNAs occurred. A similar pattern of immediate early gene activation was obtained when adenylate cyclase was stimulated with forskolin. CGRP also stimulated cyclic AMP accumulation with a half‐maximal effect in the range 2–5 nM, suggesting a possible role for cyclic AMP as a mediator of the effects of CGRP on gene expression.In contrast to the selective induction of c‐fos and junB by CGRP and forskolin, ATP led to the accumulation of all four immediate early genes studied, i.e., c‐fos, junB, c‐jun, and TIS11. Similar results were obtained when protein kinase C was stimulated with phorbol ester indicating that the induction of immediate early gene expression by ATP and CGRP involves different intracellular mechanisms. The action of ATP was mimicked by ADP and the poorly hydrolyzable analogues, ADPβS and 2‐methylthio ATP, but not by β,γ‐methylene ATP, AMP, or adenosine, indicating that the receptor mediating the actions of ATP on microglial gene expression is probably of the P2Y‐purinoreceptor type. The results suggest roles for CGRP and ATP as transcriptional activators in microglial cells

ISSN:0894-1491    

DOI:10.1002/glia.440150408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have investigated the ontogeny of MHC class I, class II, CD45, and macrophage antigens in wholemounts of normal human fetal retina at 10–25 weeks gestation (WG) using monoclonal antibodies and immunogold histochemistry. MHC class I antigens were expressed on retinal vascular endothelial cells and provided a useful marker of vessel organization from 14–25 WG. Microglial cells expressed immunoreactivity to MHC class I, class II, and CD45 antigens from 10 WG (pre‐vascularization) and macrophage S22 (Mac S22) antigen from 14 WG (post‐vascularization), although none of the antigens tested were detected on neuronal or macroglial elements. Microglia expressing MHC, CD45, and macrophage antigens occurred in both ramified and rounded forms with no close correlation being observed between morphology and antigenicity. The numbers of immunoreactive cells labeled with each of the four markers increased steadily throughout gestation in all specimens studied. Equivalent numbers of microglia expressed MHC class I, class II, and CD45 antigens in retinae at similar gestational ages; however, our data indicate that microglia expressing Mac S22 antigen comprise approximately 40% or less of the population of MHC and CD45‐immunoreactive cells during development. Topographical analyses suggest that MHC class I, class II, and CD45‐positive microglia enter the retina from both the peripheral retinal margin and the optic disc from at least 10 WG; Mac S22‐positive cells appear in association with the development of the retinal vasculature and enter the retina via the optic disc after 14 WG. © 1995 W

ISSN:0894-1491    

DOI:10.1002/glia.440150409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe creatine kinase isoenzymes play an important role in maintaining ATP levels in some cell types during times of high energy demand. We have previously shown in primary cell cultures from rat brain that glial cells express much higher levels of brain creatine kinase (CKB) mRNA than neurons. In a separate earlier study we observed that transcription of CKB mRNA in glial cells can be stimulated by a forskolin‐mediated increase in cAMP via a pathway involving protein kinase A (PKA). In this report, we show that the level of CKB mRNA in human U87 glioblastoma cells can be increased by either prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), or cholera toxin (an activator of GαSproteins). The induction of CKB mRNA occurs rapidly (with maximal induction after 6 h), is at the level of transcription, and is mediated specifically through PKA. In addition, the results indicate that both PGE1 and PGE2 use the same or related signal transduction pathways to increase CKB transcription. These results suggest that in glial cells CKB mRNA can be regulated by extracellular signals acting through G‐protein‐coupled receptors. This study may contribute to an understanding of the mechanisms underlying the previously‐reported, early postnatal increase in CKB enzyme activity in rat brain. The results are also discussed with regard to the potential involvement of the expression of prostaglandins and CKB during hypoxia and ischemia. © 1995 Wiley

ISSN:0894-1491    

DOI:10.1002/glia.440150410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractOur previous in vivo analyses have suggested that astrocytes play a key role in retinal vascularization by inducing endothelial cell differentiation. Here we demonstrate that medium conditioned by cultured rat brain astrocytes (ACM) contains factors, including transforming growth factor‐β (TGF‐β), that inhibit endothelial cell growth. Serum‐free medium conditioned for 1–3 days was tested on exponentially growing bovine retinal microvascular endothelial, aortic endothelial, mink lung epithelial CCL‐64, and Swiss mouse 3T3 fibroblast cells. The growth of all four cell types was inhibited in a dose and time‐dependent manner. CCL cells, which are used as a model for assaying TGF‐β activity, were more sensitive than the endothelial cells, suggesting that ACM contains TGF‐β. Moreover, acid treatment significantly increased the inhibitory activity of ACM, indicating that TGF‐β in ACM is predominantly in the latent form. Mouse fibroblasts, which are not affected by TGF‐β treatment under the same conditions, were also inhibited by ACM. This suggests that other inhibitory factors in addition to TGF‐β may be involved. Adsorption by an anti‐TGF‐β polyclonal antibody column substantially reduced but did not eliminate the inhibitory activity of ACM for CCL and endothelial cells. Western blot analysis of ACM and proteins eluted from the affinity column revealed a 25 kDa band that co‐migrates with TGF‐β. Comparative densitometry of the 25 kDa bands on Western blot indicated that the amount of TGF‐β in ACM is not sufficient to account for the total growth‐inhibitory activity. These experiments demonstrate directly that rat brain astrocytes express TGF‐β. They also indicate that astrocytes may produce other growth‐inhibitory factor

ISSN:0894-1491    

DOI:10.1002/glia.440150411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY