Shear-stress-responsive signal transduction mechanisms in renal proximal tubule cells

Purpose of review Phenotypic alterations resulting from flow-induced mechanical strains is a growing field of research in many cell types such as vascular endothelial and smooth muscle cells, chondrocytes or osteocytes. Although it has been acknowledged for several decades that tubular flow is a main determinant of tubular behavior in terms of vectorial transport of water and solutes, the effect of flow on other characteristics of proximal tubular cell phenotype was ignored until recently. The purpose of the review is to summarize the various effects of shear-stress, recently demonstrated in renal proximal cells. Recent findings New results demonstrate that tubular flow has pleiotropic effects on proximal tubular cells, affecting, in vitro and in vivo, the organization of the cytoskeleton, the synthesis of extracellular matrix proteases and the activity of specific transcription factors. Summary These results suggest that flow-induced mechanical strains could be one determinant of tubulointerstitial lesions during the progression of renal diseases.