To examine the effects of specific inhibition of geranylgeranyl transferase I on the expression of types I and III collagen genes in normal and systemic sclerosis (SSc) dermal fibroblasts in vitro.Methods
Fibroblasts from 2 normal subjects and 4 SSc patients were incubated with 2–10 μM of GGTI-298, a specific geranylgeranyl transferase inhibitor. Type I collagen and fibronectin production were determined by enzyme-linked immunosorbent assay. Steady-state messenger RNA (mRNA) levels for α1(I), α2(I), and α1(III) collagens and fibronectin were assessed by Northern hybridization, and the transcription of the α1(I) collagen gene was examined by transient transfections with a reporter construct containing −5.3 kb of the gene.ResultsGGTI-298 caused a dose-dependent inhibition of type I collagen production and a reduction in the steady-state levels of α1(I), α2(I), and α1(III) mRNA in normal and SSc cells. A 60–70% inhibition of type I collagen production and a 70–80% reduction in the mRNA levels for α1(I), α2(I), and α1(III) were observed at 10 μM GGTI-298. In contrast, the expression of fibronectin, cyclooxygenase 1, and GAPDH was not affected. The effects on α1(I) collagen mRNA resulted from a profound reduction in transcription of the α1(I) collagen gene promoter. GGTI-298 did not affect cellular viability or morphology.Conclusion
These results demonstrate that specific inhibition of geranylgeranyl prenylation causes a potent and selective inhibition of expression of the genes encoding types I and III collagens, without affecting cellular viability. The findings indicate that inhibition of geranylgeranyl prenylation should be further studied as a potential therapeutic approach for SSc and other fibrosing diseases.
Arthritis & Rheumatism 06/2000; 43(7):1624 - 1632. · 7.87 Impact Factor