Cyclosporin A stimulates transcription and procollagen secretion in tubulointerstitial fibroblasts and proximal tubular cells.

The brief study described in this report was undertaken to determine whether cyclosporin A had any direct effect on the expression of tubulointerstitial procollagens in cultured renal cells. Our findings indicate that murine tubulointerstitial fibroblasts secreted significantly more procollagen type I after the addition of cyclosporin A, whereas syngeneic proximal tubular cells expressed significantly more types I and IV procollagen after cyclosporin stimulation. These increases in procollagen gene product correlated concordantly with changes in the levels of cytoplasmic mRNA with procollagen-specific cDNA probes. Transfection of these fibroblasts and proximal tubular cells with chimeric gene constructs containing enhancer/promoter elements for alpha2(I) and alpha 1(IV) procollagen linked to a chloramphenicol acetyltransferase reporter gene indicates that the stimulatory effect of cyclosporin on procollagen expression depends, at least to some extent, on an increase in transcriptional activity.