Producción CyT
Medicina - Functional interaction between Aquaporin-1 (AQP1) and Epithelial Sodium Channel (ENaC). Their role in cellular volume and biomechanic
Congreso
Fecha:
2017Editorial y Lugar de Edición:
Fundación Revista MedicinaISSN:
1669-9106Resumen *
AQP1 and ENaC are both expressed in vascular endothelium. Their functions in this tissue would not be related to their canonical functions. It has been published that ENaC acts as mechano sensor stimulated by a non-genomic action of aldosterone hormone. In addition, we have reported that AQP1 permeability (Pf) is modulated by changes in membrane tension. Our aim was to study a possible functional interaction between AQP1 and ENaC which regulates cellular volume and biomechanic. The experimental model was Xenopus laevis oocyte expressing AQP1, ENaC or both protein by mRNA injection. We measured the osmotic response (OR) and the intracellular pressure (PIC) of these phenotypes challenged by different hypotonic gradients during short times (minutes). Also, these phenotypes were treated with amiloride, an ENaC inhibitor, or aldosterone. In all conditions, intra and extracellular Na+ remains in balance. We estimated the two classical parameters, Pf and water flux (Jw), to describe the OR obtained for the defined phenotypes. Both parameters were significantly greater in the AQP1-ENaC phenotype than the AQP1 one (p<0,05) and this phenomenon was independent of the value of osmotic gradient (OG). Interestingly, the experiments with amiloride showed that the OR-raise only occurred with a functional ENaC. Furthermore, aldosterone enhanced the OR and different Pf and Jw values were obtained comparing to the control (p<0,05). Regarding to the PIC, we estimated the elastic module (ξ), that reflects membrane stiffness. A significant difference (p<0,0001) in ξ values between both AQP1 phenotypes was observed. Evenmore, since AQP1 Pf behaves as a variable parameter for high OGs, we observed an enhanced deviation from linearity in the AQP1-ENaC phenotype. As a conclusion, we proposed a functional interaction between AQP1 and ENaC where the sodium channel softens cellular membrane, turning it more permeable to water. This phenomenon is improved by aldosterone short action. Información suministrada por el agente en SIGEVAPalabras Clave
NON-GENOMIC ALDOSTERONE ACTIONMEMBRANE STIFFNESSOSMOTIC RESPONSEAQP1-ENaC CO-EXPRESSION