CELL-EXTRACELLULAR MATRIX INTERACTIONS UNDER IN-VIVO CONDITIONS DURING INTERSTITIAL CELL-MIGRATION IN HYDRA-VULGARIS

Interstitial cell (I-cell) migration in hydra is essential for establi shment of the regional cell differentiation pa:ttern in the organism. All previous in vivo studies have indicated that cell migration in hyd ra is a result of cell-cell interactions and chemotaxic gradients. Rec ently, in vitro cell adhesion studies indicated that isolated nematocy tes could bind to substrata coated with isolated hydra mesoglea, fibro nectin and type IV collagen. Under these conditions, nematocytes could be observed to migrate on some of these extracellular matrix componen ts. By modifying previously described hydra grafting techniques, two p rocedures were developed to test specifically the role of extracellula r matrix components during in vivo I-cell migration in hydra. In one a pproach, the extracellular matrix structure of the apical half of the hydra graft was perturbed using beta-aminopropionitrile and beta-xylos ide. In the second approach, grafts were treated with fibronectin, RGD S synthetic peptide and antibody to fibronectin after grafting was per formed. In both cases, I-cell migration from the basal half to the api cal half of the grafts was quantitatively analyzed. Statistical analys is indicated that beta-aminopropionitrile, fibronectin, RGDS synthetic peptide and antibody to fibronectin all were inhibitory to I-cell mig ration as compared to their respective controls. beta-xyloside treatme nt had no effect on interstitial cell migration. These results indicat e the potential importance of cell-extracellular matrix interactions d uring in vivo I-cell migration in hydra.