PRODUCTION OF INFLAMMATORY MEDIATORS AND CYTOKINE RESPONSIVENESS OF AN SV40-TRANSFORMED HUMAN PROXIMAL TUBULAR EPITHELIAL-CELL LINE

Proximal tubular epithelial cells (PTEC) play a central role in the ph ysiology of the renal tubulointerstitium. To be able to study the rela tionship between tubular cells and inflammatory renal diseases the ava ilability of cultured cells is of importance. This study describes an immortalized proximal tubular epithelial cell line which was generated using SV40 DNA. To determine whether the transformation altered the c ell line, the transformed cell line was characterized phenotypically u sing different monoclonal antibodies directed against peptidases, whic h are characteristic of PTEC, such as adenosine deaminase binding prot ein (CD26), leucine amino peptidase and carboxy peptidase M by immunof luorescent staining and FAGS analysis. All peptidases were clearly pre sent on the parental cell line and the transformed cell line. However, the level of expression of the peptidases was lower on the transforme d cell line as compared to the parental nontransfected cells. The morp hology of the transformed cell line, determined using a transwell cult ure system and electron microscopy, showed a polarized morphology of t he tubular cells, tight junctions and microvilli. The transformed cell line was compared with the parental proximal tubular epithelial cells in its ability to respond to inflammatory cytokines such as IL-1 alph a, TNF-alpha, IFN-gamma. Stimulation with these cytokines resulted in enhanced production of complement components C2, C3, C4 and factor H, IL-6 and the chemokines IL-8 and MCP-1. The transformed cell line resp onded in a similar fashion as the parental cell line, although the amo unt of the different proteins produced was significantly higher in the transformed cell line. Overall, the transformed tubular cell line see ms to be a suitable model to study different effects on tubular cells in relation to inflammatory kidney diseases.