Role of LOX-1 in Ang II-induced oxidative functional damage in renal tubular epithelial cells

2010 International Journal of Molecular Medicine  
The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), plays an important role in angiotension II (Ang II)-induced hypertensive renal injury associated with pro-inflammatory responses, tubular functional damage and cellular apotosis. In this study, we report on the role of LOX-1 in Ang II-induced oxidative functional damage and underlying signaling in human renal proximal tubular epithelial cells (HRPTEpiCs). The exposure to Ang II enhanced the expression of the NADPH oxidases
more » ... p22phox, p47phox and Nox4 subunits), LOX-1 and the adhesion molecule, ICAM-1. It also promoted monocytic U937 cell adherences to HRPTEpiCs, increased reactive oxygen species formation and stimulated apotosis, which was concomitant with an increase in the activation of p38 and p44/42 mitogen-activated protein kinases (MAPK). Furthermore, the Ang II treatment disturbed the balance of the Bcl-2 family proteins, destabilized mitochondrial membrane potential, and subsequently triggered the release of cytochrome c into the cytosol, causing the activation of caspase-3. The NADPH oxidase inhibitors and LOX-1 small interfering RNA markedly ameliorated these detrimental effects by reducing LOX-1 expression and MAPK activation. The p38 and p44/42MAPK inhibitors also inhibited the Ang II-induced functional damage without affecting LOX-1 expression in the HRPTEpiCs. These observations suggest that LOX-1 mediates Ang II-induced renal tubular epithelial dysfunction. In addition, MAPK pathway activation occurs downstream of the Ang II/reactive oxygen species/ LOX-1 cascade.
doi:10.3892/ijmm_00000514 pmid:20878090 fatcat:au3xzwg2mvdy7p2ix4ul6uh57q