MODULATION OF COLLAGEN GEL CONTRACTION BY DECORIN

The small dermatan sulphate protein decorin interacts via its core pro tein with fibrillar collagens, and its glycosaminoglycan chains were p roposed to be capable of self-association. It was therefore of interes t to study the role of decorin in the contraction of cell-populated co llagen lattices. Stable transection of dihydrofolate reductase-deficie nt CHO cells with decorin cDNA resulted in impaired collagen lattice c ontraction. Using normal human skin fibroblasts in serum-free cultures , inclusion of 0.3 mu M decorin in the culture medium also led to a de layed collagen gel contraction. Protein-free dermatan sulphate and the dermatan sulphate-degrading enzyme chondroitin ABC lyase were ineffec tive. Potential interactions between dermatan sulphate chains were stu died by gel filtration. A shift in the elution position of [S-35]sulph ate-labelled decorin-derived glycosaminoglycans by unlabelled decorin could be observed only when the chains were prepared by trypsin. Chain s liberated by beta-elimination or by cathepsin C were eluted at ident ical positions in the presence or absence of decorin. It is therefore unlikely, that the effect of decorin on collagen-gel retraction is bro ught about solely by glycosaminoglycan-glycosaminoglycan interactions.