Nitric oxide and Hsp70 might modulate cellular survival during neonatal ureteral obstruction

MANUCHA WALTER; CACCIAMANI VALERIA; GARRAMUÑO VALLÉS, PATRICIA

Cordoba

Congreso; XVI Annual Scientific Meeting of Cordoba Biology Society; 2007

299. NITRIC OXIDE AND HSP70 INTERACTION MIGHT MODULATE CELLULAR SURVIVAL DURING NEONATAL UNILATERAL URETERAL OBSTRUCTION Manucha W1,2, Cacciamani V1 , Vallés P1,2. 1 Fac. Cs. Médicas U.N. de Cuyo, 2IMBECU-CONICET, Mendoza. In neonatal obstructive nephropathy, apoptosis tubular cell induction leads to tubular atrophy and loss of renal tissue. Nitric oxide (NO) has been reported as a bifunctional apoptotic regulator. A citoprotector role, interfering with the apoptosis process has been attributed to the heat shock protein 70 (HSP70) in obstruction. Objective: To study the probable NO interaction with HSP70 in the modulation of the mitochondrial apoptotic pathway during neonatal unilateral ureteral obstruction (UUO). Methodology: ?In vivo? and ?in vitro? experiments were performed in control and neonatal UUO rats after 5 and 14 days of obstruction. In vitro experiments: aliquots of control cortex homogenates were incubated in the presence of Sodium nitroprusiate (200μmol/L) and L-NAME (20mmol/L). In vivo and in vitro experiments, NO levels (Griess), inducible nitric oxide synthase expression (iNOS), procaspase 3 and HSP70 (WB). Bax and BcL2 (RT-PCR, WB), caspase 3 and NADPH oxidase activity (Fluorescence) were determinated. Coimmunoprecipitation of BcL2 and HSP70 was performed. Results: Chronic UUO (14 days) demonstrated marked apoptosis with increased caspase 3 activity, increased NADPH oxidase activity and decreased endogenous NO, BcL2 and HSP70 expression compared to control. Conversely, in vitro imposed NO demonstrated increased HSP70, BcL2 expression with decreased caspase 3 and decreased NADPH oxidase activity. Coimmunoprecipitation showed BcL2 and HSP70 interaction in the presence of exogenous NO. After 5 days of obstruction, absence of apoptosis induction and increased NO, iNOS and HSP70 protein were demonstrated. Conclusions: The results allow us to suggest that NO bioavailability might modulate HSP70 expression suppressing mithocondrial apoptotic signals through the preservation/stabilization of BcL2 and caspase 3 inhibition, during neonatal UUO.