Cell Deformation at the Air-Liquid Interface Evokes Intracellular Ca 2+ Increase and ATP Release in Cultured Rat Urothelial Cells

• Published in: Frontiers in physiology 2021, Vol.12, p.631022
• Main Authors: Wen, Jiliang, Chen, Zhenghao, Zhao, Mengmeng, Zu, Shulu, Zhao, Shengtian, Wang, Shaoyong, Zhang, Xiulin
• Format: Article
• Language: English
• ISSN: 1664-042X; 1664-042X
• DOI: 10.3389/fphys.2021.631022

Urothelial cells have been implicated in bladder mechanosensory transduction, and thus, initiation of the micturition reflex. Cell deformation caused by tension forces at an air-liquid interface (ALI) can induce an increase in intracellular Ca concentration ([Ca ] ) and ATP release in some epithelial cells. In this study, we aimed to examine the cellular mechanisms underlying ALI-induced [Ca ] increase in cultured urothelial cells. The ALI was created by stopping the influx of the perfusion but maintaining efflux. The [Ca ] increase was measured using the Ca imaging method. The ALI evoked a reversible [Ca ] increase and ATP release in urothelial cells, which was almost abolished by GdCl . The specific antagonist of the transient receptor potential vanilloid (TRPV4) channel (HC0674) and the antagonist of the pannexin 1 channel ( panx) both diminished the [Ca ] increase. The blocker of Ca -ATPase pumps on the endoplasmic reticulum (thapsigargin), the IP3 receptor antagonist (Xest-C), and the ryanodine receptor antagonist (ryanodine) all attenuated the [Ca ] increase. Degrading extracellular ATP with apyrase or blocking ATP receptors (P2X or P2Y) with pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) significantly attenuated the [Ca ] increase. Our results suggest that both Ca influx TRPV4 or pannexin 1 and Ca release from intracellular Ca stores IP3 or ryanodine receptors contribute to the mechanical responses of urothelial cells. The release of ATP further enhances the [Ca ] increase by activating P2X and P2Y receptors autocrine or paracrine mechanisms.