Back
Acta Physiologica 2012; Volume 206, Supplement 693
Joint FEPS and Spanish Physiological Society Scientific Congress 2012
9/8/2012-9/11/2012
Santiago de Compostela, Spain
17BETA-ESTRADIOL INCREASES AMILORIDE-SENSITIVE NA+ CURRENT AND GAMMAENAC SURFACE EXPRESSION VIA ACTIVATION OF PKCDELTA IN RENAL COLLECTING DUCT M1 CELLS
Abstract number: P258
Yusef1 Yamil R., Thomas1 Warren, J Harvey1 Brian
1Molecular Medicine, Royal College of Surgeons in Ireland
Objectives:
17beta-estradiol (E2) exerts a gender-specific anti-secretory effect in distal colon 1. This could provide an explanation for the fluid retention observed in females during periods of high circulating plasma E2. However, the effect of E2 on ion transport in other organs contributing to electrolyte and fluid homeostasis has not been characterised. The aim of this study was to determine whether E2 had an effect on Na+ re-absorption in the renal cortical collecting duct using the M1-CCD cell line and to reveal the molecular mechanisms underlying effects of E2 on the amiloride-sensitive epithelial Na+ channel ENaC
Materials:
M1 cells were grown as polarized monolayer and then placed in Ussing chambers to measure changes in the short-circuit currents (ISC). PKCdelta autophosphorylation at the residue Ser643 was measured by Western-blot. Total and surface abundance of gammaENaC were measured by biotinylation, Western-blot and Immunostaining
Results:
Treatment with E2 (25 nM) for 15 min increased the amiloride-sensitive ISC (Control 1.5±0.4 uA/cm2, E2 2.8±0.4 uA/cm2; n=6). The response was abolished by rottlerin (5 uM) (E2 2.4±0.4 uA/cm2, E2+rottlerin 0.6±0.3 uA/cm2; n=6) and it was not attributable to changes in the ouabain-sensitive Na+/K+-ATPase current (Control 2.9±0.2 uA/cm2, E2 3.3±0.8 uA/cm2; n=4). E2 and the ERalpha agonist PPT (1 nM) stimulated PKCdelta autophosphorylation and the amiloride-sensitive ISC. The stimulatory effect of E2 on ENaC was blocked independently by inhibitors for MMP (GM6001, 1 uM), EGFR (AG1478, 10 uM) and PLC (U-73122, 10 uM). Treatment with E2 for 30 min induced an increase in the apical membrane abundance of gammaENaC (20±2%, n=4). This effect was abolished by rottlerin
Conclusions:
E2 rapidly increases the amplitude of the ENaC current and apical surface abundance of gammaENaC. Both processes are demonstrated to be dependent on a signalling cascade transduced via ERalpha and EGFR involving PKCdelta activation
1. O'Mahony F et al. (2007). J Biol Chem 282(34), 24563-73
To cite this abstract, please use the following information:
Acta Physiologica 2012; Volume 206, Supplement 693 :P258