(Pro)renin promotes fibrosis gene expression in HEK cells through a Nox4-dependent mechanism

• Published in: American journal of physiology. Renal physiology 2011-06, Vol.300 (6), p.F1310-F1318
• Main Authors: Clavreul, Nicolas, Sansilvestri-Morel, Patricia, Magard, Delphine, Verbeuren, Tony J, Rupin, Alain
• Format: Article
• Language: English
• Subjects: ACE inhibitors; Analysis of Variance; Blotting, Western; Cells; Cells, Cultured; Effects; Fibrosis - genetics; Fibrosis - metabolism; Gene expression; HEK293 Cells; Humans; Kidney diseases; Medical treatment; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; NADPH Oxidase 2; NADPH Oxidase 4; NADPH Oxidases - genetics; NADPH Oxidases - metabolism; Phosphoproteins - genetics; Phosphoproteins - metabolism; Plasminogen Activator Inhibitor 1 - genetics; Plasminogen Activator Inhibitor 1 - metabolism; Receptors, Cell Surface - metabolism; Renin - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Superoxides - metabolism; Transforming Growth Factor beta - genetics; Transforming Growth Factor beta - metabolism
• ISSN: 1931-857X; 1522-1466
• DOI: 10.1152/ajprenal.00119.2010

The (pro)renin receptor (PRR) has recently been demonstrated to bind equally well renin and its precursor, prorenin, leading to a similar intracellular signaling independent of angiotensin II. In this study, we report that human embryonic kidney cells (HEK) exposed to renin or prorenin for 24 h in the presence of a blocking concentration of the angtiotensin-converting enzyme inhibitor perindoprilate increased superoxide anion production as measured by luminescence (lucigenin) and electron spin resonance spectroscopy (hydroxylamine radical transition). Also, both renin and prorenin increased Nox4 expression while Nox2, p47(phox), and p67(phox) remained unchanged. In an investigation of the effects of renin and prorenin on fibrosis genes, it appeared that both proteins stimulated transforming growth factor-β (TGF-β), fibronectin, and plasminogen activator inhibitor type 1 (PAI-1) expression and therefore participated to an overall switch toward a profibrotic state of the kidney cells. When the cells were transfected with a siRNA targeting the PRR, Nox4 expression was efficiently prevented as well as the increase in superoxide production, TGF-β, fibronectin, and PAI-1. Finally, we demonstrated that transfection of the cells with a Nox4-specific small interfering (si) RNA also prevented fibrosis gene expression following treatment with renin or prorenin. The results demonstrate that renin and prorenin, through their specific membrane receptor and independently of angiotensin II, promote fibrosis gene expression via a Nox4-dependent mechanism.