ROLE OF THE NA+/H+ EXCHANGER NHE1 IN THE AQP2-DEPENDENT RENAL CELL MIGRATION

DI GIUSTO GISELA; PIZZONI ALEJANDRO; WHITE ALAN; BELTRAMONE NATALIA; RIVAROLA VALERIA; FORD PAULA; CAPURRO CLAUDIA

Mar del Plata

Congreso; Reunión Conjunta SAIC SAI SAFIS 2018; 2018

SAFIS

Cell migration is the basis for many physiological and pathophysiological processes such us wound healing or metastasis. We have previously shown that Aquaporin 2 (AQP2) promotes renal cell migration. Moreover, we have already demonstrated the participation of NHE1 in the increment observed in the % of migration of AQP2-expressing cells. However, it is well known that NHE1 may contribute to cell migration in several different ways: affecting cell volume, regulating intracellular pH (pHi) and controlling cell adhesion, anchoring the cytoskeleton proteins to plasma membrane. The aim of the present work was to perform pHi measurements to evaluate if the activity of NHE1 exchanger influences the microenvironment of the lamellipodia in migrating cells. For experimental procedures two renal cell lines were used: WT-RCCD1 (not expressing AQPs) and AQP2-RCCD1 (stably transfected with AQP2). Fluorescence videomicroscopy measurements were performed in scratched monolayers: for ratiometric pHi measurements cells were loaded with the pH-sensitive probe BCECF/AM. Fluorescence data were acquired every 10s using a charge coupled-device camera connected to a computer and the Metafluor acquisition program. Changes in pHi were inferred from the ratio 490/440 of the fluorescence emitted from the lamellipodia of dye-loaded cells localized in the migrating front. Cells were incubated in control isosmotic solution or with HOE-694 (1uM) to inhibit NHE1 activity. Results showed that after incubation with HOE only AQP2-expressing cells present an acidification of their lamellipodia (Control-HOE; AQP2-RCCD1: 0.70±0.24 pH-units, n=40 cells in N=7 experiments, p