The effect of nitric oxide on tubular epithelial cell apoptosis in response to mechanical strain

LUCIANA MAZZEI; NEIL G. DOCHERTY; WALTER MANUCHA

San Luis

Congreso; XXXII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2014

Sociedad de Biología de Cuyo

Obstruction to the outflow of urine in the renal pelvis or ureter, leads to retrograde mechanical pressure transfer to the renal tubular compartment. This is the principal injury stimulus that sets in chain the inflammatory and fibrotic processes that characterize obstructive nephropathy. A primary event in this sequence is tubular cell stress and the induction of apoptosis. Wilms tumor 1 (WT-1), a key regulator of mesenchymal-epithelial transformation, is downregulated during congenital obstructive nephropathy. Of great interest, nitric oxide (NO) bioavailability associated with heat shock protein 70 (Hsp70) interaction might modulate WT-1 expression, preventing obstruction-induced cell death during neonatal unilateral ureteral obstruction (UUO). Hence, the goal of this study was to examine the effect of NO on apoptosis in response to mechanical stretch in derived tubular epithelial rat cells (NRK52E). NRK52E (N=3) were exposed to 48 hours of graded mechanical strain using the Flexcell system in the presence or absence of NG-nitro-L-arginine methyl ester (L-NAME,1mmol), L-arginine (1mmol) and sodium nitroprusside (NPS, 2mmol) or combinations and assess thereafter apoptosis by Annexin V/Propidium Iodide based flow cytometric. NRK52E submitted to mechanical stretch showed an apoptosis induction in relation to control cells. The cells with L-arginine or NPS treatments and the combination of both showed a reduction in apoptosis even in the control cells with no stress. In addition, L-NAME as well as L-NAME/L-arginine treatment, increased the apoptosis in the groups exposed to mechanical strain but not in the control group. We concluded that NO availability protects against mechanical stretch- induced apoptosis.