Abstract: Objective In order to investigate the role of adhesion between fibronectin and fibroblasts from scleroderma as well as tyrosine phosphorylated proteins induced by the adhesion on procollagen mRNA expression. Methods Fibroblasts from lesions of scleroderma were cultured in culture bottles absorbed with fibronectin. The levels of procollagen α1(I) mRNA and tyrosine phosphorylated proteins induced by the adhesion were detected by RT-PCR and immunoblotting, respectively. An inhibitor of tyrosine kinase, herbimycin A, was added to the medium to block the phosphorylation of tyrosine. The changes of procollagen mRNA and tyrosine phosphorylated proteins were further investigated. Results Adhesion between scleroderma fibroblasts and fibronectin not only induced the production of 98 000 and 65 000 tyrosine phosphorylated proteins, but also enhanced obviously the expression of procollagen α1(I) mRNA. When the phosphorylation of tyrosine was blocked, the level of procollagen α1(I) mRNA decreased significantly with the reduction of 98 000, 65 000 tyrosine phosphorylated proteins. Conclusion Adhesion between fibronectin and the fibroblasts plays an important role in enhanced expression of procollagen mRNA in scleroderma. Phosphorylation of tyrosine seems to be a key step in the process of expression of procollagen mRNA.

Key words: Scleroderma, Fibroblasts, Tyrosine phosphorylation