Effect of nitric oxide donors on renal tubular epithelial cell-matrix adhesion.

Nitric oxide (NO) and its metabolite, peroxynitrite (ONOO^-), are involved in renal tubular cell injury. We postulated that if NO/ONOO^- has an effect to reduce cell adhesion to the basement membrane, this may contribute to tubular obstruction and may be partially responsible for the harmful effect of NO on the tubular epithelium during acute renal failure (ARF).

We examined the effect of the NO donors (z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA/NO), spermine NONOate (SpNO), and the ONOO^- donor 3-morpholinosydnonimine (SIN-1) on cell-matrix adhesion to collagen types I and IV and fibronectin using three renal tubular epithelial cell lines: LLC-PK₁, BSC-1, and OK.

In LLC-PK₁ cells, DETA/NO (500 μm) had no effect, and SpNO (500 μm) had a modest effect on cell adhesion compared with controls. Exposure to SIN-1 caused a dose-dependent impairment in cell-matrix adhesion. Similar results were obtained in the different cell types and matrix proteins. The effect of SIN-1 (500 μm) on LLC-PK₁ cell adhesion was not associated with either cell death or alteration of matrix protein and was attenuated by either the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, the superoxide scavenger superoxide dismutase, or the ONOO^- scavenger uric acid in a dose-dependent manner.

These results therefore support the possibility that ONOO^- generated in the tubular epithelium during ischemia/reperfusion has the potential to impair the adhesion properties of tubular cells, which then may contribute to the tubular obstruction in ARF.