Search PubMed⌕ Search

Biomedical subjects

A Prochiantz

Publications and source records attributed to A Prochiantz.

At least 91 records · Page 5Linked to original sources
PubMed1988

A 140-kilodalton protein is released from cultured astrocytes by phosphatidylinositol phospholipase C.

Astrocytes in culture synthesize a 140-kilodalton (140-kD) protein (protein 140) that is released into the medium on incubation with phosphatidylinositol phospholipase C. This molecule therefore belongs to the class of proteins anchored to the external side of the cell membrane through a glycolipid moiety. Protein 140 is present in astrocyte cultures derived from two different regions of the brain and is not expressed by neurons in vitro. It differs from neuronal cell adhesion molecule 120 or 140 and is probably identical to a protein of 140 kD present in C6 glioma cells.

Animals↗
PubMed1987

Gabaergic neurons of the hippocampus: development in homotopic grafts and in dissociated cell cultures.

The hippocampus taken from E18-E19 rat embryos was dissociated into a cell suspension and was either grafted into the hippocampus of adult rats or cultured. The growth of GABAergic neurons was examined using a GABA directed antiserum. The implanted tissue was capable of survival and growth without exhibiting a laminar organization. Most of the various morphological neuronal types could be observed, establishing different types of synapses; however, granule neurons were rarely encountered. A substantial proportion of GABA-positive neurons was detected within the graft with profuse labelling of the neuropil. In cultures issued from the same cell suspension, GABA-immunoreactive neurons were numerous and had different morphologies. Altogether these data suggest that GABA neurons express a high potential for growth and sprouting in vitro and in vivo.

Animals↗
PubMed1987

MAP2 expression and neuritic outgrowth and branching are coregulated through region-specific neuro-astroglial interactions.

Embryonic neurons from the rat striatum and mesencephalon were plated on mesencephalic or striatal astrocytes in 4 possible combinations. It was found that specific traits are expressed by the neurons when they are grown on homotopic astrocytes (neurons and astrocytes from the same region). These traits are the following: 1. The number of cells stained with an antibody raised against the microtubule-associated protein 2 (MAP2) is higher in homotopic than in heterotopic cocultures. This is true for both mesencephalic and striatal neurons. 2. In homotopic conditions, there is an increase in the number of cells having more primary neurites and branching points. This effect is observed for both neuronal populations but is more pronounced in mesencephalic neurons. 3. The intensity of MAP2 staining was correlated with the branching ability of the neurons. First, on comparing MAP2-positive and MAP2-negative cells, it was found that, in any combination (homotopic and heterotopic cocultures), the number of primary neurites and branching points was much higher in MAP2-positive cells. In fact, almost no branching activity was found in MAP2-negative neurons. Second, within the MAP2-positive neuronal population, the higher number of branching points observed under homotopic neuro-astroglial conditions was mostly due to the neuritic compartment, which was strongly and homogeneously stained with the anti-MAP2 antibody. These observations strongly suggest that the astrocytic environment regulates the synthesis and/or intracellular distribution of MAP2, as well as the morphology of the neurons, and that this regulation is region specific.

Animals↗
PubMed1987

Further studies on the role of astroglia in brain neurons maturation and morphogenesis.

Using in vitro cultures of dissociated brain neurons and astrocytes, we have compared the morphologies of mesencephalic and striatal neurons cultured for two days on mesencephalic and striatal astrocytes in the four possible combinations. From these comparisons, it appears that: 1. Neurons grown on co-regionalized (homotopic) astrocytes have more primary neurites and branching points than neurons grown on heterotopic astrocytes. 2. The total neuritic length is only slightly affected by the type of co-culture. 3. The branched arborization which develop faster on homotopic astrocytes present several dendritic features. Following these morphological observations, we have been able to demonstrate: 1. That mesencephalic astrocytes (but not striatal astrocytes) secrete trypsin sensitive factors different from laminin and FGF that increase the number of primary neurites and branching points but have no or little effect on total neuritic length. 2. That mesencephalic astrocytes (but not striatal astrocytes) present at their surface a 190 KD glycoprotein specifically recognized by the fucose-specific lectin UEA.

Animals↗
PubMed1986

The rotating 6-hydroxydopamine-lesioned mouse as a model for assessing functional effects of neuronal grafting.

Mice were first administered intrastriatal injections of 6-hydroxydopamine and subsequently a sub-group was given neural cell suspension grafts prepared from 14-day-old fetal ventral mesencephalic mouse tissue. Six and 8 weeks after transplantation the mice in the grafted group exhibited a significant reduction in amphetamine-induced turning behaviour towards the lesioned side compared to non-grafted lesioned controls. Six of the 7 mice that had surviving grafts containing histofluorescent dopamine neurons eventually showed a reversed motor side bias with more amphetamine-induced turning in a direction away from the transplant.

Amphetamine↗
PubMed1986

Two simian virus 40 (SV40)-transformed cell lines from the mouse striatum and mesencephalon presenting astrocytic characters. I. Immunological and pharmacological properties.

Dissociate cultures were initiated from embryonic rostral mesencephalic and striatal tissues dissected from the mouse brain and previously incubated with a simian virus 40 (SV40) suspension. After several weeks in culture foci of fastly dividing cells were resuspended and cloned by successive dilutions. Several clones expressing the SV40 nuclear T antigen were obtained by these procedures and two of them, one mesencephalic (F7-Mes) and one striatal (F12-Str) were screened for the expression of glial or neuronal characters. Both clones possess adenylate cyclase-linked beta 2-adrenergic receptors. They also take up and synthesize gamma-aminobutyric acid (GABA) in amounts compatible with a glial origin. As is the case for astrocytes, the uptake of GABA is inhibited by beta-alanine and rather insensitive to the presence of diaminobutyric acid (DABA), a specific inhibitor of the neuronal GABA carrier. The most convincing evidence that F7-Mes and F12-Str belong to the astrocytic lineage comes from the fact that the two cell lines synthesize glial fibrillary acidic protein (GFAP) as demonstrated by immunofluorescence and immunoblotting. In an accompanying paper we also show that these lines behave like astrocytes when considered from the point of view of neuroglial interactions.

Animals↗
PubMed1986

Two simian virus 40 (SV40)-transformed cell lines from the mouse striatum and mesencephalon presenting astrocytic characters. II. Interactions with mesencephalic neurons.

In an accompanying paper we report the characterization on the basis of pharmacological and immunological criteria of two astrocytic cell lines originating from the rostral mesencephalon and the striatum of the embryonic mouse (F7-Mes and F12-Str). This report compares the interactions of primary mesencephalic neurons with the astrocytic clones to that displayed with either an SV40-transformed fibroblastic clone (BT2) or primary mesencephalic (G-Mes) and striatal (G-Str) astrocytes. We show that BT2 differs from all other cell types (F7-Mes, F12-Str, G-Mes and G-Str). Indeed, as opposed to these cells BT2 is a poor substratum for neuronal adhesion or neuritic growth. This was clearly demonstrated by morphological examination of cocultures of the tested cells with either mesencephalic explants or dissociated cells. In addition a statistical analysis is provided which only concerns the dopaminergic (DA) neurons visualized by autoradiography after specific uptake of [3H]DA. The number of DA cells attached, the total length of their neurites and the degree of branching behaviour were examined. With the help of these criteria we show that F7-Mes and F12-Str are very similar to primary astrocytes and differ highly significantly from BT2. However, although sharing the main astrocytic features, F7-Mes and F12-Str do not differ from one another in their ability to induce the branching of DA neurites as their non-transformed counterparts do.

Animals↗
PubMed1986

Two simian virus 40 (SV40)-transformed cell lines from the mouse striatum and mesencephalon presenting astrocytic characters. III. A light and electron microscopic study.

In two preceding papers we described the cloning of two astrocytic cell lines by simian virus 40 (SV40) transformation of embryonic mouse mesencephalon (F7-Mes) and striatum (F12-Str). The characterization of these lines as belonging to the astrocytic lineage is based on pharmacological, immunocytochemical and physiological data. Here we present quantitative and qualitative data on the morphological aspects of these two astrocytic clones observed under light and electron microscopy. We show that the clones present ultrastructural characters reminiscent of the morphology of young astrocytes. On one hand, they are rather similar to primary astrocytes in culture; on the other, they differ both from a clonal fibroblastic cell line (BT2) and from embryonic mouse fibroblasts in primary culture. These astroblastic clones display 4 morphologically different cell populations which we called types I, II, III and IV. Types II and III are very similar and represent the most predominant cells; their morphologies strongly remind of that of astroblasts. Type I corresponds to glioblasts and does not account for more than 15-20% of the total population. Type IV, which is very similar to differentiated velamentous astrocytes, normally represent ca. 5% of the cells. However, when the transformed cells are treated with mitomycin or mitomycin + dibutyryl cyclic AMP (dbcAMP), the proportion of type IV cells increases very much (up to more than 50% of the cells) while types I, II and III become less numerous. Morphological analysis therefore confirms that the two cell lines derived from the SV40 transformation of 14-day-old embryonic mesencephalic and striatal cells belong to the astrocytic lineage. Moreover, it seems that they can differentiate in vitro in cell culture conditions either spontaneously or under the action of pharmacological treatments known to enhance normal astrocyte maturation.

Animals↗
PubMed1985

Survival of intracerebrally grafted rat dopamine neurons previously cultured in vitro.

Fetal rat dopamine (DA) neurons were cultured in vitro for a 6-day period and transported, after redissociation, for 2 days prior to being grafted to the neostriatum of adult rats with 6-hydroxydopamine lesions of the ascending nigrostriatal pathway. In 2 of the 5 graft recipients that were tested for amphetamine-induced motor asymmetry, the grafts eliminated the lesion-induced turning behaviour within 3-6 weeks after transplantation. Fluorescence histochemistry revealed surviving grafts in all 6 recipients at 7 weeks after transplantation, containing between 42 and 125 DA neurons. The number of surviving DA neurons in the 3 non-compensated rats was below the minimum number of cells previously found to be necessary for functional effects on turning behaviour to occur.

Animals↗
PubMed1985

Astrocytic cerebellar cell clones synthesize the beta' isoforms of the beta-tubulin protein family.

We have analysed the isotubulin pattern of three astrocytic cell clones, derived from spontaneously established permanent cell cultures originating from 8-day postnatal mice cerebellar explants, in comparison with that of primary astroglial cultures from embryonic brain and cerebellum. These astrocytic clones, which may represent the different astroglial cell types of mouse cerebellum, did not produce the alpha- and beta-acidic isoforms, these being found only in cells of neuronal lineage. However, the three astrocytic clones, but not the primary astroglial cultures, did synthesize the beta'-tubulin isoforms; in addition quantitative analysis of the beta' proteins showed a positive correlation between the ability of the cells to extend processes and their synthesis of the beta' isoforms. These data suggest that the presence of beta'-tubulin is not specific for neuronal cells but may be related to the ability of cells from the nervous system to extend processes.

Animals↗
PubMed1985

Neuronal growth and shape.

Several aspects of neuronal growth related to the questions of shape acquisition, target attainment and target recognition are reviewed with an emphasis on how external cues and fields intervene in these developmental processes.

Animals↗
PubMed1985

In vitro studies on the maturation of mesencephalic dopaminergic neurons.

The use of neural culture is illustrated by the study of the in vitro development of a well defined neuronal system in the brain: the mesencephalic dopaminergic neurons of the rodent species. After a brief survey of its ontogenetic development, the various experimental techniques for its study in vitro are described. Such an approach has allowed the discovery of influences brought by a target area, like the striatum, on the maturation of these neurons. A new kind of local morphogenic interactions between these neurons and their glial partners is also reported.

Animals↗