Activation of Piezo1 channels enhances spontaneous contractions of isolated human bladder strips via acetylcholine release from the mucosa

Enhanced spontaneous bladder contractions (SBCs) have been thought one of the important underlying mechanisms for detrusor overactivity (DO). Piezo1 channel has been demonstrated involved in bladder function and dysfunction in rodents. We aimed to investigate the modulating role of Piezo1 in SBCs activity of human bladder. Human bladder tissues were obtained from 24 organ donors. SBCs of isolated bladder strips were recorded in organ bath. Piezo1 expression was examined with reverse transcription-quantitative polymerase chain reaction and immunofluorescence staining. ATP and acetylcholine release in cultured human urothelial cells was measured. Piezo1 is abundantly expressed in the bladder mucosa. Activation of Piezo1 with its specific agonist Yoda1 (100 nM-100 μM) enhanced the SBCs activity in isolated human bladder strips in a concentration-dependent manner. The effect of Yoda1 mimicked the effect of a low concentration (30 nM) of carbachol, which can be attenuated by removing the mucosa, blocking muscarinic receptors with atropine (1 μM), and blocking purinergic receptors with pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS, 30 μM), but not by tetrodotoxin (1 μM). Activation of urothelial Piezo1 with Yoda1 (30 μM) or hypotonic solution induced the release of ATP and acetylcholine in cultured human urothelial cells. In patients with benign prostatic hyperplasia, greater Piezo1 expression was observed in bladder mucosa from patients with DO than patients without DO. We conclude that upregulation and activation of Piezo1 may contribute to DO generation in patients with bladder outlet obstruction by promoting the urothelial release of ATP and acetylcholine. Inhibition of Piezo1 may be a novel therapeutic approach in the treatment of overactive bladder.

ATP; Acetylcholine; Overactive bladder; Piezo1 channel.