Inducible nitric oxide synthase inhibitor 1400W increases Na⁺,K⁺‐ATPase levels and activity and ameliorates mitochondrial dysfunction in Ctns null kidney proximal tubular epithelial cells

Abstract

Nitric oxide (NO) has been shown to play an important role in renal physiology and pathophysiology partly through its influence on various transport systems in the kidney proximal tubule. The role of NO in kidney dysfunction associated with lysosomal storage disorder, cystinosis, is largely unknown. In the present study, the effects of inducible nitric oxide synthase (iNOS)-specific inhibitor, 1400W, on Na ,K -ATPase activity and expression, mitochondrial integrity and function, nutrient metabolism, and apoptosis were investigated in Ctns null proximal tubular epithelial cells (PTECs). Ctns null PTECs exhibited an increase in iNOS expression, augmented NO and nitrite/nitrate production, and reduced Na ,K -ATPase expression and activity. In addition, these cells displayed depolarized mitochondria, reduced adenosine triphosphate content, altered nutrient metabolism, and elevated apoptosis. Treatment of Ctns null PTECs with 1400W abolished these effects which culminated in the mitigation of apoptosis in these cells. These findings indicate that uncontrolled NO production may constitute the upstream event that leads to the molecular and biochemical alterations observed in Ctns null PTECs and may explain, at least in part, the generalized proximal tubular dysfunction associated with cystinosis. Further studies are needed to realize the potential benefits of anti-nitrosative therapies in improving renal function and/or attenuating renal injury in cystinosis.

The Role of Cystinosin in the Intermediary Thiol Metabolism and Redox Homeostasis in Kidney Proximal Tubular Cells

“…The mitochondria-targeted superoxide dismutase mimetic, mito-TEMPO, repaired dysfunctional mitochondria and improved epithelial function and integrity in these mice, presumably by attenuating the overproduction of ROS in the mitochondria. In agreement with these observations, we observed a dramatic reduction in the mitochondrial transmembrane potential and ATP content in Ctns −/− murine PTCs [67].…”

Endothelial nitric oxide synthase limits host immunity to control disseminated Candida albicans infections in mice

“…Inflammatory signals can also induce iNOS expression via NFκB in renal proximal tubule epithelial cells [40,41]. These are the most abundant cells in the kidney cortex, and they also express eNOS [40,42]. Further studies are needed to determine which cell types in infected WT kidneys have altered eNOS activity and the mechanism by which this limits iNOS expression.…”