TRANSCRIPTIONAL CONTROL OF HUMAN TENONS CAPSULE FIBROBLAST COLLAGEN-SYNTHESIS IN-VITRO BY GAMMA-INTERFERON

Purpose. Gamma-interferon (gamma-IFN) has been shown to be a potent in hibitor of collagenous protein production independent of its effects o n noncollagenous protein production and cell proliferation in vitro. T o understand further the processes controlling tissue fibrosis and the potential use of gamma-IFN as an antifibrotic treatment after glaucom a filtering surgery, the in vitro effects of recombinant gamma-IFN on procollagen mRNA production were studied. Methods. Subconfluent human Tenon's capsule fibroblast cultures were exposed to 10, 50, 500, and 1 000 U/ml of human recombinant gamma-IFN for 48 hours and to 500 U/ml f or 12, 24, and 72 hours. After the incubation period, polyA(+) mRNAs w ere isolated by oligo (dT) cellulose columns, separated according to s ize by electrophoresis through a denaturing agarose gel, and transferr ed to an activated nylon membrane for Northern blot analysis. The leve ls of type III (alpha(1)) procollagen, type I (alpha(1)) procollagen, and fibronectin (noncollagenous protein) mRNA were determined by hybri dization with radiolabeled cDNA probes specific for these components f ollowed by autoradiography. Results. Densitometric analysis showed gam ma-IFN selectively inhibited type III and type I procollagen mRNA synt hesis from 24% (10 U/ml) to 99% (1000 U/ml) while leaving fibronectin mRNA synthesis unaffected. The degree of inhibition was also time depe ndent; more inhibition occurred with increasing incubation time. Concl usions. These results indicate that gamma-IFN is able to regulate coll agen synthesis at the transcriptional level and that its inhibition is relatively specific. Gamma-interferon's specific inhibitory effects m ay offer advantages over current therapies in modulating the fibrotic response after glaucoma filtering surgery.