Glial Cell Development and Reactivity in Reaggregating Brain Cell Culture

Abstract

Cell-cell interactions playing a crucial role in brain ontogeny appear to be mediated by the exchange of biologically active, diffusible substances as well as by direct cell-cell contacts. These different epigenetic factors may act on a given cell in such a complementary way, that the absence or alteration of one of these signals may critically change the cell’s responsiveness to other micro environmental stimuli. Therefore, in order to study the role of hormonal and humoral factors in the developing brain, it seems important to use model systems which allow the formation of natural cell-cell contacts. This requirement is fulfilled by rotation mediated aggregating cell cultures, in which dissociated cells reassemble spontaneously into three-dimensional structures. Thus they re-establish a maximum of histotypic organization and cell-cell interactions (1–7). In addition, this particular cellular configuration favors the use of chemically defined media for both the preparation and maintenance of these cultures (8). Owing to these unique features, aggregating brain cell cultures have proven to be valuable for developmental studies, such as investigations on the modulatory role of hormones in the brain (8 – 11). In order to give some view to the potentialities and limitation of this culture system, the present report reviews recent work on glial cell development in aggregating cell cultures, and their responsiveness to epidermal growth factor (EGF) as a function of developmental stage and culture conditions.