Stimulation of collagen secretion by factors released from injured arterial smooth muscle cells in culture.

Collagen secretion stimulating activity (CSSA) of bovine arterial smooth muscle cells (SMC) was released to the culture medium after injury of cultured SMC by dimethylsulphoxide-soluble particles from cigarette smoke, but not from uninjured cells. Total protein secretion and DNA synthesis were not stimulated in new SMC by the conditioned medium containing the CSSA. The presence of protease inhibitors before assay did not influence CSSA, but this activity was completely abolished if protease inhibitors were present before injury was induced. The sensitivity to trypsin and heat suggested a protein nature of the activity. CSSA exhibited marked charge and size heterogeneity when subjected to ion exchange and gel chromatographies, and the fraction procedures revealed CSSA peaks with approximate molecular weights greater than 1.5 X 10(6), 450 000, 250 000, 15 000 and less than 10 000, respectively. No CSSA peaks were seen when conditioned medium from uninjured cells was used. It is concluded that SMC injured by dimethylsulphoxide extractable material from cigarette smoke release protein(s) stimulating secretion of newly synthesized collagen, but not of total protein and DNA synthesis, in new SMC cultures.