Expression and significance of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-1 in an animal model of renal interstitial fibrosis induced by unilateral ureteral obstruction

To evaluate the pathological roles of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-1 in rat renal interstitial fibrosis, we examined the expression, localization and effect on growth of ADAMTS-1 in a normal rat kidney cell line (NRK-49F). Increased ADAMTS-1 mRNA expression was observed in the kidney by in situ hybridization after induction of unilateral ureteral obstruction (UUO) in male Wistar rats, the mRNA was localized in the renal tubular epithelial cells in the outer stripe of the outer medulla in the UUO kidney. On the other hand, no positive signals were observed in the sham-operated-kidney. Western-blot analysis of stable human embryonic kidney 293 (HEK293) transformant cells expressing rat ADAMTS-1 containing the V5 tag using anti-V5 tag monoclonal antibody revealed the presence of two post-translationally processed bands in the cells: an 87-kDa band with a metalloproteinase motif and 65-kDa band with a thrombospondin motifs. On the other hand, secretion of the 65-kDa protein into the culture supernatants from the transformant cells was confirmed. Treatment with the culture supernatant of the transformant cells potently reduced the uptake of 3H-thymidine in the NRK-49F cells, no such inhibitory effect was observed with the culture medium of the HEK293 cells. These results suggest that the UUO-induced expression of ADAMTS-1 in the rat renal tubular epithelial cells may actively contribute to the inhibition of DNA synthesis in the renal interstitial fibroblasts via the 65-kDa moiety with thrombospondin motifs.