Long-term adaptation to hypotonicity in human Müller cells involve a decrease in AQP4 expression and cell proliferation

DI GIUSTO, GISELA; CAPURRO, CLAUDIA; NATALIA BELTRAMONE; VANINA NETTI; ALAN WHITE; FORD, PAULA

Mar del Plata

Congreso; Reunión Anual de la Sociedad Argentina de Investigación Clínica, LXVI Reunión Anual de la sociedad Argentina de Inmunología y Reunión Anual de la Sociedad Argentina de Fisiología.; 2018

During neuronal activity, Müller cells are surrounded by a hypotonic environment, leading to cell swelling and consequently to a regulatory volume decrease (RVD) response. We previously demonstrated in human Müller cells (MIO-M1) that RVD depends on the efflux of KCl, Taurine and Glutamate, as well as water outflow through Aquaporin-4 (AQP4). However, adaptive changes to long-term hypotonicity (HT) are largely unknown. It was reported that AQP4 was also involved in cell growth in astrocytes, although the mechanisms were not described yet. The aim of this study was to correlate HT-related changes in gene expression triggered by MIO-M1 cell swelling with physiological processes necessary for long-term HT adaptation. Gene transcription by MIO-M1 cells exposed to control or HT (ΔOsm:100 mOsm) for 30 minutes was compared using Affymetrix microarray for 10000 genes. Microarray data analysis was performed with GenArise software and DAVID Bioinformatics Resources Database. AQP4 expression was evaluated by Western Blot and cell proliferation by cell count experiments in both experimental conditions. HT induced the upregulation (Z-score>2SD) of 241 genes and downregulation (Z-score