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At least 199 records · Page 11Linked to original sources
PubMed1988

Rat ependyma and microglia cells express class II MHC antigens after intravenous infusion of recombinant gamma interferon.

Recombinant rat gamma-interferon was administered to Lewis rats by continuous intravenous infusion. After a 3-day administration period, at various dosages, a constant pattern of class II major histocompatibility complex (MHC) antigen induction was found in the brains and cerebella. Immunohistological double staining for class II antigens and glial fibrillary acidic protein showed that the majority of newly induced cells were microglia. The endothelium of large blood vessels and ependymal cells also expressed class II antigens. These findings demonstrate that systemically raised interferon levels can affect MHC antigen expression in the brain. Astrocytes are obviously not the primary cell type to acquire class II reactivity, and thus potential antigen-presenting capacity, in this situation.

Animals↗
PubMed1996

Presence of macrophage migration inhibitory factor (MIF) in ependyma, astrocytes and neurons in the bovine brain.

We investigated the immunohistochemical localization of a cytokine macrophage migration inhibitory factor (MIF) in the bovine brain. MIF was present in the ependymal cell linings of the cerebral ventricles throughout. Double immunostaining of the section with anti-glial fibrillary acidic protein (GFAP) antibody and with anti-MIF antibody showed that the astrocytes present in subependymal layer were immunoreactive for MIF. In the hippocampus, the pyramidal cells in the CA3 and CA4 subfields and the granule cells of the dentate gyrus were immunoreactive. The bundles of mossy fibers were stained along their projections to CA3 and CA4 regions. The nuclei of the subpopulation of these MIF-immunoreactive cells were also immunostained. These results indicated the widespread distribution of a cytokine, MIF, in the bovine brain and suggested the possibility that MIF might play additional roles than a proinflammatory mediator role in the brain.

Animals↗
PubMed2006

A TAT-modified fusion protein efficiently penetrates mouse hypoglossal nuclei from transduced ependyma.

Future gene therapy for brainstem variant amyotrophic lateral sclerosis may be technically difficult if gene therapy vectors are injected near vital cardiorespiratory centers or if large portions of the tongue and pharyngeal muscles must be peripherally injected for retrograde transport of vectors to motor neurons. In this study we show that it is possible to deliver recombinant proteins to the hypoglossal nuclei without brainstem or muscle injections, by taking advantage of enhanced uptake of fusion proteins containing the protein transduction domain from the human immunodeficiency virus TAT protein. Adenoviral vectors expressing either TAT-modified or native beta-glucuronidase (beta-gluc) were injected into the lateral cerebral ventricles of mice, transducing ventricular epithelium down to the level of the obex in the brainstem. There was significant uptake into the hypoglossal nuclei of TAT-modified but not native beta-glucuronidase. The TAT-modified beta-gluc appeared to encompass half or more of the hypoglossal nuclei as visualized by retrograde labeling with cholera toxin subunit b in adjacent sections. TAT-modification of gene products may allow a relatively non-invasive approach to brainstem gene therapy via cerebroventricular injection.

Adenoviridae↗
PubMed2003

Localization of angiotensin II (AT1)-receptor-immunoreactive fibres in the hypothalamus of rats: angiotensin II-sensitive tanycytes in the ependyma of the third ventricle?

Scanning the hypothalamus of rats for receptor binding sites of the octapeptide hormone angiotensin II (ANG II), we observed ANG II-sensitive fibres in the ventrolateral hypothalamus. The ANG II (AT(1))-receptor-immunoreactive processes originate from cells-probably tanycytes-embedded in the base and the ventrolateral walls of the third ventricle and reach into the retrochiasmatic area, the ventrolateral hypothalamus and the median eminence.

Angiotensin II↗
PubMed1983

Filipin resistance in intermediate junction membranes of guinea pig ependyma: possible relationship to filamentous underlying.

Plasma membranes in intermediate junctions of ependymal cells are found to show considerable resistance to the antibiotic filipin, suggesting low cholesterol in these membranes. Further, ependymal cells were treated with cytochalasin B (CB) infused into the cerebral ventricle in vivo, and then incubated with filipin. When treated with CB, intermediate junctions show a decrease in their underlying density, mainly composed of microfilaments, and their membranes are found to be more affected by filipin. This reduction of resistance to the antibiotic is clearly demonstrated by thin-section and freeze-fracture as well as quantitative analysis. Nonjunctional lateral membranes, however, show no significant difference in the degree of filipin effect whether treated with CB or not. Although biochemical data on lipid composition have not been available for the intermediate junction membranes, we bring forward a possibility that resistance to filipin in these membranes may come not from less cholesterol but from morphological membrane stability brought about by the filamentous underlying.

Animals↗
PubMed2003

Immunocytochemical localization of zinc transporter 3 in the ependyma of the mouse spinal cord.

We report, for the first time, the light microscopical and ultrastructural appearance of ZnT3-immunoreactivities in the ependymal cells of the central canal of the mouse spinal cord. Light microscopy revealed the presence of ZnT3-immunoreactive (Ir) ependymal cells in 1 microm thick epon sections stained by the ABC method. The ZnT3-Ir cells were observed at all levels of the spinal cord, but were a little more numerous in lumbosacral segments than in cervicothoracic segments. The ZnT3-Ir cells had large, ovoid nuclei with abundant cytoplasm, and protruded into the lumen of the central canal. Our ultrastructural findings suggest that the ZnT3-Ir ependymal cells possess secretory activity directed towards the central canal. We propose that they may play a role in the trans-ependymal mechanism responsible for zinc homeostasis between cerebrospinal fluid and the central area of the gray matter.

Animals↗
PubMed1998

Localization of a G protein Gi2 in the cilia of rat ependyma, oviduct and trachea.

In previous studies, the localization of a pertussis toxin-sensitive G protein was demonstrated in ependymal cilia, but the identification of the subtype of G protein was inconsistent. To clarify this issue, we studied the localization of Goalpha, Gi1alpha, Gi3alpha and Gi2alpha in the ciliated ependymal cells and in the cilia of some other tissues of rats using specific antibodies. The cilia of the ependymal cells that line the ventricular cavity of the brain were intensely immunoreactive for Gi2alpha, but not for Goalpha, Gi1alpha or Gi3alpha. Immunoblot analysis demonstrated higher levels of Gi2alpha in the ependymal cilia-rich pellet than in the motor area of the parietal cortex. At the ultrastructural level, the immunoreactivity specific for Gi2alpha was found predominantly in the cilia, but rarely in the microvilli or the basal bodies of ependymal cells. In cross-sections, the immunoreactivity specific for Gi2alpha was observed only in cell membranes, in particular, in the inner electron-dense leaflet of the trilaminar structure. In addition to that in the ependymal cilia, such specific localization of Gi2alpha was observed in the motile cilia in other tissues, including the oviduct and trachea. By contrast, the stereocilia in the ductus deferens were not immunopositive for Gi2alpha. These findings suggest that Gi2 might play an important role in the signal transduction in ciliary membrane-associated function(s) of the ependymal cells, oviduct and trachea.

Animals↗
PubMed2005

Transduction of the choroid plexus and ependyma in neonatal mouse brain by vesicular stomatitis virus glycoprotein-pseudotyped lentivirus and adeno-associated virus type 5 vectors.

Evaluation of gene transfer into the developing mouse brain has shown that when adeno-associated virus serotype 1 (AAV1) or AAV2 vectors are injected into the cerebral lateral ventricles at birth, widespread parenchymal transduction occurs. Lentiviral vectors have not been tested by this route. In this study, we found that injection of lentiviral vectors pseudotyped with vesicular stomatitis virus glycoprotein (VSV-G) resulted in targeted transduction of the ependymal cells lining the ventricular system and the choroid plexus along the entire rostrocaudal axis of the brain, whereas a Mokola pseudotype transduced only a few cells after injection into the neonatal ventricle. In contrast, when lentiviral vectors pseudotyped with either VSV-G or Mokola glycoprotein are injected into the adult mouse brain, they transduce similar patterns of cells. An Ebola-Zaire-pseudotyped vector did not transduce any neonatal CNS cells, as was also the case for adult parenchymal injections. Long-term gene expression (12 months) occurred with a constitutively active mammalian promoter and a self-inactivating long terminal repeat (LTR), whereas the cytomegalovirus promoter in a vector with an intact LTR was expressed only in short-term experiments. We found that an AAV5 vector also targeted the ependymal and choroid plexus cells throughout the ventricular system. This vector exhibited limited penetration from the ventricle to other structures, which was significantly different from the previously reported patterns of transduction after intraventricular injection of AAV1 and AAV2 vectors.

Animals↗
PubMed2001

Presence of sst2(a) receptor immunoreactivity in rat ependyma and tanycytes.

Somatostatin sst2(a) receptor was observed, by immunofluorescence, in ependymal cells and in tanycytes of the wall of the ventricle and the hypothalamic recess of the male rat median eminence. Strong immunoreactivity for the receptor protein was observed in lateral tanycytes (alpha-type) while a moderate signal was seen in medial tanycytes (beta-type). In high magnification the immunoreactive material, of moderate intensity, had a coarse granular appearance. Only few of the alpha-tanycytes also displayed immunoreactive GFAP. The apical portion of the ependymal cells as well as of tanycytes contained immunoreactive S-100 (alphabeta). Since rather high levels of somatostatin are demonstrated to occur in the cerebrospinal fluid of the third ventricle, it is suggested that somatostatin via the sst2(a) receptor may regulate the physiology of tanycytes.

Animals↗
PubMed1990

Repair of the ependyma in hydrocephalic brains.

Hydrocephalus was induced in 12-day-old rats by the cisternal infusion of concentrated kaolin suspension. At 19 days of age, a lesion, 100 or 150 microns in diameter, was made in the ependymal lining of the lateral ventricles. Animals were killed at intervals from 1 h to 20 days after the lesion was made. The damaged area was examined by scanning electron microscopy, light and transmission electron microscopy. Between 1 h and 48 h the hole was still open. Small round cells, identified as free subependymal cells, were associated with the edges of the hole from 1 h after the lesion was made. From 48 h, the lesion was completely covered with cell bodies and their processes and no hole was present. Signs of differentiation were seen in the free subependymal cells from 4 days, the cells becoming more electron lucent. By 15 days, three types of cell arrangement were seen within the damaged area: 1 clusters of small cells, with few processes, resembling subependymal cells; 2 small numbers of cells with flat cytoplasmic processes which formed the lining of the ventricular wall; 3 clusters of cells with long thin processes attached to the surface of the ventricular wall but not forming the ependymal lining. The results of this study suggest that, in the hydrocephalic brain, ependymal damage and the repair of a defect within the ventricular wall is initiated by subependymal cells.

Animals↗
PubMed1992

Ependyma of the goat. Part IV. Ependymal lining of the median eminence in goats under physiological and experimental conditions.

The sexual differentiation of the ME ependymal lining surface structure has been proved in goats. Suitable hormonal preparations applied to females during anestrus induced on the median eminence the same picture as that during estrus. Only after gonadectomy in both the females and males there were dense macrophages-like SEC on the ME protruding from the deeper layers of the eminence. Their potential function is discussed.

Anestrus↗
PubMed1980

Ventricular ependyma of normal and hydrocephalic subjects: a scanning electronmicroscopic study.

Recent scanning electronmicroscopic studies of the ependymal surfaces of the lateral, third and fourth ventricles of a variety of animals have shown that most areas are covered by numerous cilia. In this paper, the density of the ciliary population in each of the ventricles is illustrated with material taken from human and rat brains. The authors' examination of Hy3 mice with hydrocephalus, and a number of other reports of examinations of animals with genetic and artificially induced hydrocephalus, have shown that the cilia are lost only from the ependymal surfaces covering those parts of the ventricular wall which are stretched and thinned by the raised intraventricular pressure. Thus the loss of the cilia is most probably the result of the hydrocephalus, and not its cause. Theories concerning the functions of the cilia are reviewed, and a new one accounting for why they are present in such large numbers is suggested. It is proposed that the cilia, together with the ventricular system and the cerebrospinal fluid, provide a cooling system for the brain.

Animals↗
PubMed1981

Cytadsorption of Mycoplasma pulmonis to rat ependyma.

Mycoplasma pulmonis was inoculated intracerebrally into neonatal rats. Hydrocephalus was induced, and the lateral ventricles and aqueduct were examined by scanning electron microscopy. Mycoplasmas were observed to be cytadsorbed to the ependymal surface.

Adsorption↗