ISOLATION AND CHARACTERIZATION OF CHONDROITIN SULFATE PROTEOGLYCANS FROM EMBRYONIC QUAIL THAT INFLUENCE NEURAL CREST CELL BEHAVIOR

The movement of neural crest cells is controlled in part by extracellu lar matrix. Aggrecan, the chondroitin sulfate proteoglycan from adult cartilage, curtails the ability of neural crest cells to adhere, sprea d, and move across otherwise favorable matrix substrates in vitro. Our aim was to isolate, characterize, and compare the structure and effec t on neural crest cells of aggrecan and proteoglycans purified from th e tissues through which neural crest cells migrate. We metabolically r adiolabeled proteoglycans in E2.5 quail embryos and isolated and chara cterized proteoglycans from E3.3 quail trunk and limb bud. The major l abeled proteoglycan was highly negatively charged, similar in hydrodyn amic size to chick limb bud versican/PG-M, smaller than adult cartilag e aggrecan but larger than reported for embryonic sternal cartilage ag grecan. The molecular weight of the iodinated core protein was about 4 00 kDa, which is more than reported for aggrecan but less than that of chick versican/PG-M. The proteoglycan bore chondroitin sulfate glycos aminoglycan chains of 45 kDa, which is larger than those of aggrecan. It lacked dermatan sulfate, heparan sulfate, or keratan sulfate chains . It bound to collagen type I, like aggrecan, but not to fibronectin ( unlike versican/PG-M), collagen type IV, or laminin-1 in solid phase a ssays and it bound to hyaluronate in gel-shift assays. When added at c oncentrations between 10 and 30 mu g/ml to substrates of fibronectin, trunk proteoglycan inhibited neural crest cell spreading and migration . Attenuation of cell spreading was shown to be the most sensitive and titratable measure of the effect on neural crest cells. This effect w as sensitive to digestion with chondroitinase ABC. Similar cell behavi or was also produced by aggrecan and the small dermatan sulfate proteo glycan decorin; however, 30-fold more aggrecan was required to produce an effect of similar magnitude. When added in solution to neural cres t cells which were already spread and migrating on fibronectin, the em bryonic proteoglycan rapidly and reversibly caused complete rounding o f the cells, being at least 30-fold more potent than aggrecan in this activity. (C) 1997 Academic Press.