A 120 kDa nuclear phospholipase Cgamma1 protein fragment is stimulated in vivo by EGF signal phosphorylating nuclear membrane EGFR.

Intraperitoneal injection of epidermal growth factor (EGF) into mice resulted in the phosphorylation of liver nuclei phospholipase Cgamma1 (PLCgamma1) at the tyrosine, coincident with the time course of nuclear membrane epidermal growth factor receptor (EGFR) activation. The function of PLCgamma1 in mice liver nuclei was attributed to a 120 kDa protein fragment. This 120 kDa protein was immunoprecipitated with the isozyme specific PLCgamma1 antibody and was found to be sensitive to a PLCgamma1 specific blocking peptide.

Differential upregulation of extracellular matrix molecules associated with the appearance of granule cell dispersion and mossy fiber sprouting during epileptogenesis in a murine model of temporal lobe epilepsy.

We have investigated changes in the extracellular matrix of the hippocampus associated with the early progression of epileptogenesis in a murine model of temporal lobe epilepsy using immunohistochemistry. In the first week following intrahippocampal injection of the glutamate agonist, domoate, there is a latent period at the end of which begins a sequential upregulation of extracellular matrix (ECM) molecules in the granule cell layer of the dentate gyrus, beginning with neurocan and tenascin-C. This expression precedes the characteristic dispersion of the granule cell layer which is evident at 14 days post-injection when the first recurrent seizures can be recorded.

Immunoelectron microscopic localization of the M6a antigen in rat brain.

The monoclonal antibody M6-7, which recognizes both native and denatured immunopurified M6a antigen, was used in the present immunocytochemical study to localize its corresponding antigen in young rat brain. Strong labelling was observed in the cerebellar molecular layer, which corresponds to heavily stained axon terminals originating from granule cells. The immunodeposit, as observed by electron microscopy, is present only on the cytoplasmic side of the presynaptic membrane and on the membrane of synaptic vesicles.

Paternal alcohol exposure: developmental and behavioral effects on the offspring of rats.

The effect of paternal alcohol exposure on neurochemical and behavioral parameters was investigated using as a model system glial cells derived from newborn rat brain and cultured for 4 weeks. The total brain neurochemical parameters from rats born to mothers sired by an alcohol treated father were also investigated. Enzymatic markers of nerve cell development (enolase isoenzymes and glutamine synthetase) and the defense system (superoxide dismutase) against free radicals formed during alcohol degradation were measured in order to evaluate nerve cell damage.

Distribution of mitochondrial manganese superoxide dismutase among rat glial cells in culture.

Enzymatic antioxidant defense systems, like superoxide dismutase (SOD), may protect neuronal and glial cells from reactive oxygen species (ROS) damage. Beside the cytosolic constitutive CuZn SOD, mitochondrial manganese SOD (Mn SOD) represents a ROS inducible enzyme which should allow the adaptation of brain cells to variation in ROS concentrations resulting from their oxidative metabolism. Using immunocytochemistry, the distribution of Mn SOD among the various representatives of the rat brain glial population (astroglia and microglia in primary culture as well as oligodendroglia in secondary culture) has been examined.

Oligodendrocytes express different isoforms of beta-amyloid precursor protein in chemically defined cell culture conditions: in situ hybridization and immunocytochemical detection.

The expression of beta-amyloid precursor protein (betaAPP) by astrocytes is well documented; however, data concerning oligodendrocytes remain controversial. The main goal of the present study was to determine whether or not oligodendrocytes in culture constitutively express the different betaAPP isoforms. Oligodendrocytes were cultured in a chemically defined medium that avoids putative effects of unknown serum factors on oligodendrocyte development.

Trophic action of pharmacological substances with a guanidine group on mouse neuroblastoma cells and chick ganglionic neurons in culture.

A series of substances (designated CTQ compounds) with a guanidine group have been synthesized and tested for their ability to promote neuronal survival and neurite outgrowth. Mouse neuroblastoma clonal cell lines grown in serum-containing medium for 10 days as well as primary cultures of embryonic chicken ganglion neurons grown in serum-free defined medium for 1 or 2 days have been used for the experiments. Among the various CTQ compounds (CTQ1-CTQ20) tested, only CTQ8 exerted positive neurotrophic effects on these peripheral neuronal cells.

Modelling of the binding site of the human m1 muscarinic receptor: experimental validation and refinement.

Our model of the human m1 muscarinic receptor has been refined on the basis of the recently published projection map of bovine rhodopsin. The refined model has a slightly different helix arrangement, which reveals the presence of an extra hydrophobic pocket located between helices 3, 4 and 5. The interaction of series of agonists and antagonists with the m1 muscarinic receptor has been studied experimentally by site-directed mutagenesis.

A comparative study of the distribution of alpha- and gamma-enolase subunits in cultured rat neural cells and fibroblasts.

We report the presence and distribution of alpha (ubiquitous) and gamma (neuron-specific) subunits of the dimeric glycolytic enzyme enolase (2-phospho-D-glycerate hydrolase) in cultured neural cells. The gamma gamma enolase is found in vivo at high levels only in neurons and neuroendocrine cells. Neuronal cells in culture also contain relatively high levels of alpha gamma and gamma gamma enolase.

[Cloning of testican/SPOCK in man and mouse. Neuromuscular expression perspectives in pathology].

We have recently cloned a novel proteoglycan initially identified in human testis and hence previously called testican. A close examination of the overall protein structure reveals three main regions: four osteonectin/SPARC-like domains encompassing the amino-terminal and central part of the deduced protein, a Kazal-like motif overlapping the third domain, and the CWCV domain in the carboxyl-terminal end region of the protein core. We propose to call it SPOCK, the acronym of SPARC/Osteonectin CWCV and Kazal-like domains proteoglycan, according to its specific multidomain structure.

Basic fibroblast growth factor (bFGF) injection activates the glial reaction in the injured adult rat brain.

Reactive gliosis is a reaction of glial cells to trauma which is characterized by a phenotypic modification of astrocytes, as well as by a proliferation and a migration of some of these cells to form a glial scar. This scar is currently considered as a physical impediment to neuronal regrowth but it may also be involved in wound healing since the astrocytes beside microglia play a phagocytic role in the clearance of post-traumatic debris. Growth factors are released in the area of the injury and at least some of them could be involved in gliosis.

Lectin activities of cytokines and growth factors: function and implications for pathology.

The discovery that certain cytokines have carbohydrate-binding (lectin) properties opens new concepts in the understanding of their mechanism of action. The carbohydrate-recognition domain, which is localized opposite to the receptor-binding domain, makes these molecules bi-functional. The expression of the biological activity of the cytokine relies on its carbohydrate-binding activity which allows the association of the cytokine receptor with molecular complexes comprising the specific kinase involved in receptor phosphorylation and in specific signal transduction.

Interleukin 2 is a lectin that associates its receptor with the T-cell receptor complex.

To determine the nature of the mechanism by which the binding of interleukin-2 (IL-2) to its receptor (IL-2R beta) induces IL-2R beta phosphorylation by the tyrosine kinase p56lck associated with the T-cell receptor (TCR) complex, we investigated the possibility that this mechanism was due to the putative lectin activity of IL-2 ([Sherblom, Sathyamoorthy, Decker and Muchmore (1989) J. Immunol. 143, 939-944].

Development of glial cells cultured from prenatally alcohol treated rat brain: effect of supplementation of the maternal alcohol diet with a grape extract.

The aim of this work was to investigate the effect of supplementation of a maternal alcohol diet with a grape extract on glial cell development. Glial cells were cultured during 4 weeks from cortical brain cells of the new born offspring in DMEM medium supplemented with fetal calf serum. Enzymatic markers of nerve cell development were measured (enolase isoenzymes and glutamine synthetase).

Expression of the neuron-specific enolase gene by rat oligodendroglial cells during their differentiation.

We have examined the regulation of neuron-specific gamma-enolase gene (NSE) expression in oligodendrocytes at various steps of their differentiation/maturation. We have demonstrated for the first time that NSE is expressed in oligodendroglial cells in vitro and in vivo, and only at a certain stage of differentiation. A heterogeneity of the gamma subunit was observed in cultured oligodendrocytes and the same one was found in adult rat brain.

Influence of basic fibroblast growth factor and astroglial cells on the ultrastructure of developing rat brain neuronal precursors in vitro.

We have examined the ultrastructural aspect of neuronal precursors derived from 14-day-old rat embryos during their development under various culture conditions. Cells maintained in serum-free medium which have developed for 1 week in vitro present ultrastructural features of young neurons. They contain many free ribosomes and microtubules, but few other organelles and incompletely developed Golgi apparatus.

Phospholipids inhibit proteolysis of protein kinase C alpha by mM calcium-requiring calpain.

The alpha isoform of protein kinase C (PKC alpha) is rapidly hydrolyzed by mM Ca(2+)-requiring calpain (calcium-activated neutral proteinase) under cell-free conditions (Shea et al, 1994, FEBS Lett. 350:223). In the present study, we demonstrate that this hydrolysis is inhibited by phosphatidyl serine, diacylglycerol, phosphatidyl choline, phosphatidyl inositol, and phosphatidic acid.

Human lymphocyte activation is associated with the early and high-level expression of the endogenous lectin CSL at the cell surface.

Lymphocytes undergo activation in response to antigens, cytokines, lectins and antibodies interacting with specific cell-surface molecules or through substances influencing signal transduction pathways. This study shows that human T- and B-cells stimulated using phorbol esters or plant lectins express early (2 h using phorbol esters and 24 h using plant lectins) a high level of a polyvalent carbohydrate-binding protein, the cerebellar soluble lectin (CSL), which is in part externalized. The lectin, immunologically related to CDw70, interacts with specific glycoprotein ligands of the lymphocyte surface, including CD3 on T-cells and CD24 on B-cells.

Molecular species analysis of 1,2-diglycerides on phorbol ester stimulation of LA-N-1 neuroblastoma cells during proliferation and differentiation.

1,2-Diacyl-sn-glycerol (DAG) is a product of cell activation that has emerged as an important intracellular messenger whose primary function appears to be the activation of protein kinase C. They originate by the activation of phospholipases, which hydrolyze different phospholipids depending on the external stimulus and the nature of the cells, leading to the production of different molecular species. In the present study the quantitative changes in the total mass and the molecular species of DAG formed on phorbol ester (12-O-tetradecanoyl-phorbol 13-acetate) stimulation were investigated in proliferating and retinoic acid (RA)-differentiated human LA-N-1 cells.

Effect of manganese on the development of glial cells cultured from prenatally alcohol exposed rats.

Maternal alcohol abuse is known to produce retardation in brain maturation and brain functions. Using cultured glial cells as a model system to study these effects of alcohol we found an alcohol antagonizing property for manganese (Mn). Mn was added to the alcohol diet (MnCl2 25 mg/l of 20% v/v ethanol) of pregnant rats.

Comparative immunohistochemical study of C1G5F2 antigen and myelin/oligodendrocyte glycoprotein (MOG) expression in brain of several animal species.

The localisation of the myelin/oligodendrocyte specific antigen C1G5F2 and the myelin/oligodendrocyte glycoprotein (MOG) was studied in parallel in the brain of various species throughout the phylogenetic line of vertebrates. This immunofluorescence study was performed on unfixed brain sections by using the newly described monoclonal antibody C1G5F2 and polyclonal anti-MOG antibody. The antigen C1G5F2 is detected from the reptilian class onwards whereas MOG is only found in mammals.

70-kDa heat shock protein expression in cultured rat astrocytes after hypoxia: regulatory effect of almitrine.

Induction of heat shock proteins (Hsps), especially the 70-kDa family, is well observed in nervous tissues in response to various stressful conditions. By using rat astrocytes in primary culture, the expression of the inducible (Hsp70) and the constitutive (Hsc70) 70-kDa Hsps immunoreactivity of cells exposed to hypoxic conditions has been investigated. We observed that exposure of astroglial cells to an hypoxic-normoxic sequence induces a significant decrease of Hsc70 immunoreactivity.

A new oligodendrocyte specific plasma membrane surface protein identified by a monoclonal antibody produced in vitro.

This paper describes a novel monoclonal antibody (C1G5F2) derived from mice splenocytes immunized in vitro with a wheat germ agglutinin glycoprotein fraction isolated from bovine central nervous system (CNS) myelin. Immunohistochemical reactions with C1G5F2 were investigated on rat brain sections during the active period of myelination. From day 10 to 13 postnatally, no stained structures were observed throughout the whole brain.