Neurobiology 7. (1999)

1. szám - Preliminary notes

Neurobiology; 7 (1) pp. 85-86 (1999) Preliminary note CHANGES IN CELL ADHESION AND CELL MOTILITY DURING INDUCED NEUROGENESIS, IN VITRO SCHLETT, K.,1 CZIROK, A.,2 TÁRNOK, К.,' HAIMAN, О.,2 VlCSEK, T.2 and MADARÁSZ, E.1 'Department of Comparative Physiology and 2Department of Atomic Physics, Eötvös Loránd University, Budapest, Hungary NE-4C immortalised neuroectodermal progenitor cells (1) isolated from embryonic brain vesicles of p53-deficient transgenic mice have been used to study the cellular interactions during in vitro neurone formation induced by all-trans retinoic acid. Previous studies on morphological pattern formation by NE-4C cells (2) revealed that induced cells assemble into aggregates in the early phases of the neurogenesis. Recent studies were addressed to investigate the time course of cell aggregation and the changes in cell motility during the first few days of neuronal induction. Computer-aided videomicroscopy developed in our laboratories allowed a real-time mapping and mathematical analyses of cell proliferation, migration, and cell association in the critical period of neuronal commitment. Immunocytochemical methods were used to check the presence of cell adhesion molecules NCAM and Cadherins in definite phases of neuron formation. In the first 48 hours of induction, treatment with retinoic acid resulted in a significant reduction of the average velocity of cell migration. In this period, the cells form compact but transient aggregates. By the fourth day of induction, neuronally non-committed cells migrate out of the aggregates, while neuronal cell bodies remain appearantly in close contact with each other. Mathematical analysis of migratory paths revealed that the aggregation ofNE-4C cells is controlled mainly by changes in cell adhesivity and not by any soluble cell-attractants. Immunocytochemical studies on cell adhesion molecules expressed by NE-4C cells demonstrated a continuous expression of Cadherins by induced cells. Heavy labelling with antiN-CAM antibodies, on the other hand, was first demonstrated within the transient aggregates, on the second day of retinoic acid induction. In later phases of neuronal differentiation, only cells 1218-8068/99 $ 5.00 © 1999 Akadémiai Kiadó, Budapest

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