Role of urotensin II in advanced glycation end product-induced extracellular matrix synthesis in rat proximal tubular epithelial cells

摘要

Urotensin II (UII) was first recognized for its constrictive and natriuretic properties in fish almost 40 years ago, and recent studies have suggested that it exerts pro-fibrotic effects in a number of cell lines. In this study, we aimed to evaluate the role of UII in extracellular matrix (ECM) synthesis and secretion in advanced glycation end product (AGE)-stimulated rat proximal tubular epithelial cells (NRK-52E cells). UII promoted the proliferation of the NRK-52E cells in a dose-dependent manner over a concentration range of 10(-10)-10(-8) mol/l and this effect was partly inhibited by both nimodipine and EDTA. Furthermore, AGE-BSA promoted the mRNA and protein expression of UII, fibronectin (FN) and collagen IV (ColIV) in the NRK-52E cells in a dose- and time-dependent manner. In addition, UII promoted the mRNA expression and protein secretion of transforming growth factor (TGF)-beta 1, FN and Col IV by the NRK-52E cells. Our results suggest that UII promotes the proliferation of NRK-52E cells, an effect which is mediated by the influx of extracellular calcium ions. In addition, our data indicate that AGEs promote UII expression in NRK-52E cells, and that TGF-beta 1 signaling is a candidate pathway mediating the involvement of UII in renal fibrosis. Collectively, our data suggest that the UII-TGF-beta 1 signaling may be an important factor in tubulointerstitial nephropathy in diabetes.