Role of aquaporin-2 during cell growth and cell death in renal cortical collecting duct cells

PILAR FLAMENCO; VALERIA RIVAROLA; LUCIANA MELAMUD; JUAN FERNADEZ; LUCIANO GALICIA; PAULA FORD; CLAUDIA CAPURRO

Pucón, Chile,

Congreso; XXIII Congresos de la Asociación Latinoamericana de Ciencias Fisiológicas (ALACF); 2009

We have reported that AQP2 expression is critical for a rapid regulatory volume response in renal collecting duct cells. Changes in cell volume may act as signals for basic cell functions such as proliferation and apoptosis. The aim of this work was to investigate the role of AQP2 during cell cycle progression and apoptosis in renal cells. WT (not expressing AQPs) and AQP2-RCCD1 cells (transfected with AQP2) were used. Cell growth/death was evaluated by different approaches (flow cytometry, fluorescence videomicroscopy, DNA laddering, etc). Results demonstrate that AQP2 expression raises the rate of cell proliferation linked to an increased proportion of cells in G0/G1 phase. When apoptosis occurs three features distinguish AQP2 from WT cells: (i) the rate of apoptosis is significantly increased; (ii) the pharmacological blockade of volume-regulatory K+ and Cl− channels prevented apoptosis only in AQP2 cells and (iii) the water permeability is reduced before DNA degradation only in AQP2 cells. These results suggest that under cell growth/death changes in cell volume occurs and AQP2 would act as a sensor leading to a co-ordinated activation of specific mechanisms controlling these events.