Immunohistochemical localization of glial fibrillary acidic protein (GFAP) and vimentin in the subcommissural organ of the Mongolian gerbil (Meriones unguiculatus)

Summary The chemical composition of intermediate filaments (IF's) in the ependyma of the subcommissural organ (SCO) of the Mongolian gerbil (Meriones unguiculatus) was investigated immunohistochemically in paraffin-embedded tissue. Antibodies against glial fibrillary acidic protein (GFAP), vimentin, neurofilament proteins and cytokeratins were used. Only GFAP and vimentin were detected in the non-specialized diencephalic ependyma and in the ependymocytes of the SCO. Staining could be observed in apical and basal processes of the SCO-cells. The latter processes extended into the posterior commissure up to the subpial surface, thus establishing a well-developed leptomeningeal route of ependymal projections. In contrast to the homogeneous vimentin-labeling, the SCO was particularly immunoreactive for GFAP in its lateral aspects and in the supraand precommissural parts. The coexpression of GFAP and vimentin in a subclass of SCO-ependymocytes was demonstrated on differentially immunostained semithin sections. The present study confirms the glial nature of the SCO-ependyma, which has been a matter of debate recently. It appears from this investigation that the high degree of secretory activity in the SCO does not necessarily lead to the disappearance of glial IF proteins. Moreover, the SCO-cells belong to the expanding group of mature astroglia, which is characterized by coexpression of GFAP and vimentin. The morphological similarity between SCO-ependymocytes and tanycytes is underscored by their common immunoreactivity against these two IF proteins. In view of the absence of GFAP from the rat SCO, interspecific differences must be considered in the evaluation of the IF protein composition.     

Immunohistochemical identification of supportive cell types in the enteric nervous system of the rat colon and rectum

Summary The non-neuronal, supportive cells of the enteric nerve plexus were investigated in the colon and rectum of adult and developing rats by means of immunohistochemistry, utilizing antisera against GFA protein and S-100 protein. Immunoreactivity to GFA protein was almost exclusively found in cells associated with the myenteric plexus and a small number of cells within the submucous ganglia. On the other hand, the use of S-100 protein antiserum resulted in the visualization of all supportive elements in the enteric nervous system. However, two types of supportive cells could be tentatively differentiated in the enteric nerve plexus during the second week of postnatal development, using GFA protein and S-100 protein antisera; GFA protein-positive cells were clearly discernible from S-100 protein-positive cells in terms of both the morphological profiles and immunohistochemical properties. It was assumed that at least two different types of supportive cells are contained in the enteric nerve plexus. We suggest that in the enteric nervous system the terms glial cells and Schwann cells should be employed to designate the supportive cells containing GFA and S-100 proteins, and cells containing S-100 protein, respectively. We discuss the possibility that glial cells are associated with the parasympathetic preganglionic fibres directly derived from the central nervous system, while Schwann cells originate from the neural crest.     

Developmental expression of glial markers in ependymocytes of the rat subcommissural organ: role of the environment

Summary The rat subcommissural organ (SCO), principally composed of modified ependymocytes (a type of glial cell), is a suitable model for the in vivo study of glial differentiation. An immunohistochemical study of the ontogenesis of rat SCO-ependymocytes from embryonic day 13 to postnatal day 10 shows that these cells express transitory glial fibrillary acidic protein (GFAP) from embryonic day 19 until postnatal day 3. However, S100 protein (S100) is never expressed in the SCO-cells, contrasting with the ventricle-lining cells of the third ventricle, which contain S100 as early as embryonic day 17. Environmental factors could be responsible for the repression of GFAP and S100 in adult rats, because GFAP and S100 are observed in ependymocytes of SCO 3 months after being grafted from newborn rat into the fourth ventricle of an adult rat. Neuronal factors might be involved in the control of the expression of S100, since after the destruction of serotonin innervation by neurotoxin at birth, S100 can be observed in some SCO-ependymocytes of adult rats. On the other hand, GFAP expression is apparently not affected by serotomin denervation, suggesting the existence of several factors involved in the differentiation of SCO-cells.     

Distribution of myosin and the glial fibrillary acidic protein (GFA Protein) in rat spinal cord and in the human frontal cortex as revealed by immunofluorescence microscopy

Summary The glial fibrillary acidic (GFA) protein and myosin were localized in rat spinal cord and human frontal cortex using specific antibodies against GFA protein from human spinal cord and highly purified smooth myosin from chicken gizzard by means of an indirect immunofluorescence microscopical approach. A strong GFA protein and myosin immunoreactivity was found in astrocytes of the white and grey matter and in the external glial limitans membrane. The very fine branches of astrocytic processes stained with antiGFA protein, but not with anti-myosin. Similar results were obtained with the human frontal cortex, where myosin antibodies failed to reveal the very fine branches of protoplasmic astrocytes.As a whole, staining with the GFA protein antiserum was more crisp than with the myosin antibody.Thanks are due to Professor J.R. Wolff, Max-Planck Institute for Biophysical Chemistry, Göttingen, for stimulating discussions, to Ursula König, Christa Mahlmeister and Renate Steffens for skilful technical assistance, and to Heidi Waluk for the photographic workSupported by grants from Deutsche Forschungsgemeinschaft (Br 634/1, Dr 91/1, Un 34/4, Ste 105/19)Dedicated to Prof. Dr. med. H. Leonhardt on the occasion of his 60. birthday     

Glial cells positive for glial fibrillary acidic protein in the neurohypophysis of the Djungarian hamster (Phodopus sungorus)

Summary The presence and distribution of the glial fibrillary acidic protein (GFAP; an astrocytic marker protein associated with glial filaments) in the neurohypophysis of the Djungarian hamster (Phodopus sungorus) were investigated immunohistochemically. Our study revealed characteristic GFAP-staining patterns within the median eminence, infundibular stem and neural lobe. In the whole neurohypophysis, few glial cells showed immunoreactivity. In the neural lobe, immunopositive pituicytes appeared preferentially in the periphery. At the ultrastructural level, we found some pituicytes containing filaments, most notably in their processes. We thus demonstrated that, in contrast to the GFAP-immunoreactivity of cultured pituicytes, pituicytic GFAP-expression in vivo coincides with the presence of electron-microscopically detectable filaments.     

Filiform papillae as a sensory apparatus in the tongue: An immunohistochemical study of nervous elements by use of neurofilamcnt protein (NFP) and S-100 protein antibodies

Summary Nervous elements supplying the filiform papillae of the tongue of cattle and rats were investigated using immunohistochemistry against neurofilament protein (NFP) and glia-specific S-100 protein. The rod-shaped bovine filiform papillae were heavily keratinized along their entire length and lacked the connective tissue core that occurs in other mammals. Instead, the core was located posterior to the filiform papilla. The base of the bovine filiform papillae was invaded vertically by laminar connective tissue papillae. The core contained a large number of NFP-positive nerve fibers, most of them terminating as free endings in its anterior margin. NFP-positive nerves gathered around the anterior ridge of the epithelium at the base of the core and occasionally penetrated into the epithelium. The laminar connective tissue papillae at the base of the filiform papilla also contained NFP-positive nerve fibers. The core contained S-100-immunoreactive lamellated corpuscles, which were identified as simple corpuscles in electron micrographs. The structure and innervation of the bovine filiform papilla suggest that they represent a specialized sensory apparatus. The pyramidal filiform papillae of the rat were smaller, each containing a simple connective tissue core. Few NFP-positive nerve fibers from the nerve plexus entered the core. Filiform papillae are thus less specialized in rats than in cattle.     

Immunocytochemical localization of S-100 protein in stellate cells (folliculo-stellate cells) of the adenohypophysis in the monkeys Macaca irus and Cercopithecus aethiops

Summary With the use of an antibody against bovine S-100 protein, it was possible to reveal a characteristic cell type in the pars distalis and the pars tuberalis of the monkey Macaca irus. In the adenohypophysis of Cercopithecus aethiops, labeled cells were present in the pars distalis, pars tuberalis, and pars intermedia. These cells, so-called folliculo-stellate cells, were found in all pituitaries studied. Surprisingly, an antibody against human S-100 protein did not label the stellate cells of the adenohypophysis. However, in Macaca irus, this antibody gave a strong positive reaction with various other cell types (interstitial cells of the pineal gland, Müller cells of the retina, autonomic ganglionic cells, glial cells of the central nervous system, Schwann cells, Bergmann glia of the cerebellum, fat cells, reticular cells of lymphoid organs). By use of double immunoenzymatic labeling, it was evident that stellate cells are spatially related either to somatotropes, prolactin cells, corticotropes, or to glycoprotein-containing cells. Thus, a specific relationship to a particular endocrine-cell type could not be observed.Dr. M.P. Dubois died in Tours (France) on March 30, 1986, aged 65     

Differential protein expression in ovaries of uninfected and Babesia-infected southern cattle ticks, Rhipicephalus (Boophilus) microplus

We used gel electrophoresis and mass spectrometry to investigate differences in protein expression in ovarian tissues from Babesia bovis-infected and uninfected southern cattle tick, Rhipicephalus (Boophilus) microplus. Soluble and membrane proteins were extracted from ovaries of adult female ticks, and analyzed by isoelectric focusing (IEF) and one-dimensional or two-dimensional (2-D) gel electrophoresis. Protein patterns were analyzed for differences in expression between infected and uninfected ticks. 2-D separation of proteins revealed a number of proteins that appeared to be up- or down-regulated in response to infection with Babesia, in particular membrane/membrane-associated proteins and proteins in a low molecular mass range between 6 and 36 kDa. A selection of differentially expressed proteins was subjected to analysis by capillary-HPLC-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). Among the ovarian proteins that were up-regulated in infected ticks were calreticulin, two myosin subunits, an endoplasmic reticulum protein, a peptidyl-prolyl cis–trans isomerase (PPIase), a cytochrome c oxidase subunit, a glutamine synthetase, and a family of Kunitz-type serine protease inhibitors. Among the down-regulated ovarian proteins were another PPIase, a hemoglobin subunit, and a lysozyme. This study is part of an ongoing effort to establish a proteome database that can be utilized to investigate specific proteins involved in successful pathogen transmission.