Exogenous basement-membrane-like matrix stimulates adrenergic development in avian neural crest cultures

The development of quail trunk neural crest cultures was dramatically altered when the cultures were overlaid with a gel of reconstituted basement membrane (RBM) components derived from the Engelbreth-Holm-Swarm sarcoma. In the presence of the RBM gel overlay, the number of catecholamine-positive (CA+) cells that developed was increased 50-fold, while the final number of melanocytes and total cells was only half that seen in the control cultures. The presence of the RBM gel overlay did not alter the time of onset of differentiation of the CA+ cells or melanocytes. The stimulation of CA+ cell number was not observed with type IV collagen substrates, laminin substrates or type I collagen gel overlays with or without added laminin. The stimulation of CA+ cell development was dependent on initial plating density. The number of CA+ cells that developed in the presence of the RBM gel was proportional to the initial plating density at 80-320 cells mm-2, whereas no CA+ cells were observed below 20 cells mm-2 and only a few CA+ cells were detected at 40 cells mm-2. There was, however, extensive cell division and differentiation of melanocytes and unpigmented cells at the lower initial plating densities. When the RBM gel was used as a substrate, rather than as an overlay, a striking rearrangement of cells into interconnected strands was observed. After several days in culture, melanocytes, CA+ cells and unpigmented cells were present in these strands. These results indicate that molecules associated with a reconstituted basement-membrane-like matrix are a potent stimulatory influence on adrenergic development and also act to inhibit the production of other cell types in neural crest cultures.