AUTHOR=Wen Jiliang , Chen Zhenghao , Zhao Mengmeng , Zu Shulu , Zhao Shengtian , Wang Shaoyong , Zhang Xiulin 

TITLE=Cell Deformation at the Air-Liquid Interface Evokes Intracellular Ca2+ Increase and ATP Release in Cultured Rat Urothelial Cells

JOURNAL=Frontiers in Physiology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.631022

DOI=10.3389/fphys.2021.631022

ISSN=1664-042X

ABSTRACT=Bladder urothelial cells have been implicated in bladder mechanosensory transduction. Cell deformation caused by tension forces at an air-liquid interface (ALI) can induce intracellular Ca2+ concentration ( [Ca2+]i) increase and ATP release in some epithelial cells. In this study, we aimed to examine the cellular mechanisms underlying ALI induced [Ca2+]i increase in cultured urothelial cells. ALI was created by stopping the influx of the perfusion but maintaining efflux. [Ca2+]i increase were measured using Ca2+ imaging method. ALI evoked reversible [Ca2+]i increase and ATP release in urothelial cells, which was almost abolished by GdCl3. The specific antagonist of TRPV4 channel (HC0674) and the antagonist of pannexin-1 channel (10panx) reduced [Ca2+]i increase, respectively. The blocker of Ca2+-ATPase pumps on ER (Thapsigargin), IP3 receptor antagonist (Xest-C), ryanodine receptor antagonist (ryanodine) reduced [Ca2+]i increase, respectively. Degrading extracellular ATP with apyrase, or blocking ATP receptors (P2X or P2Y) with PPADS significantly reduced [Ca2+]i increase. Our results suggest that both Ca2+ influx via TRPV4 or pannexin-1 and Ca2+ release from intracellular Ca2+ store via IP3 or ryanodine receptors contribute to mechanical responses of urothelial cells. ATP release further enhance [Ca2+]i increase by acting P2X and P2Y receptors via autocrine or paracrine mechanisms.