Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB104

Poster Communications

UT-B Osmoregulation in RT4 Urothelial Cell Line

A. Farrell1, J. Fitzgerald1, M. Torella Planas1, M. O'Neill1, G. Stewart1

1. School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland.


UT-B urea transporters are essential for normal bladder function. They protect bladder cells from the damaging effects of high urea concentrations (1). RT4 cells, derived from a human bladder papilloma, are a well-established cell model system for the human urothelium (2). UT-B1 urea transporters are highly expressed in human bladder tissue (3.). Aquaporin 3 (AQP3) transmembrane transporters are highly expressed in bladder cells and are subject to osmoregulation in the presence of NaCl (4). This study employed RT4 cells to test the hypothesis that UT-B urea transporters are subject to osmoregulation when exposed to increased NaCl concentrations. RT4 cells were cultured in media with a range of osmolalities for 48 hours, using either mannitol or sodium chloride. End-point polymerase chain reaction (PCR) and Western blotting experiments were carried out. Densitometry measurements were analysed. Western blotting results for mannitol treatments show visibly significant increases in AQP3 protein abundance (P<0.05, n= 9, ANOVA). UT-B, GAPDH and NaKATPase gave no statistically significant change with increasing mannitol concentration. NaCl-treated cells had statistically significant changes in protein expression for both UT-B (P<0.01, n= 7, ANOVA) and AQP3 (P<0.01, n=7, ANOVA), while GAPDH and NaKATPase protein expression remained unchanged. NaCl-induced, but not mannitol-induced, changes in external osmolality appear to regulate UT-B protein abundance in the RT4 cell line.

Where applicable, experiments conform with Society ethical requirements