Functional Expression of Transient Receptor Potential and Piezo1 Channels in Cultured Interstitial Cells of Human-Bladder Lamina Propria

Abstract

The interstitial cells in bladder lamina propria (LP-ICs) are believed to be involved in sensing/afferent signaling in bladder mucosa. Transient receptor potential (TRP) cation channels act as mechano- or chemo-sensors and may underlie some of the sensing function of bladder LP-ICs. We aimed to investigate the molecular and functional expression of TRP channels implicated in bladder sensory function and Piezo1/Piezo2 channels in cultured LP-ICs of the human bladder. Bladder tissues were obtained from patients undergoing cystectomy. LP-ICs were isolated and cultured, and used for real-time reverse transcription-quantitative polymerase chain reaction, immunocytochemistry, and calcium-imaging experiments. At the mRNA level, TRPA1, TRPV2, and Piezo1 were expressed most abundantly. Immunocytochemical staining showed protein expression of TRPA1, TRPV1, TRPV2, TRPV4, TRPM8, as well as Piezo1 and Piezo2. Calcium imaging using channel agonists/antagonists provided evidence for functional expression of TRPA1, TRPV2, TRPV4, Piezo1, but not of TRPV1 or TRPM8. Activation of these channels with their agonist resulted in release of adenosine triphosphate (ATP) from LP-ICs. Inhibition of TRPV2, TRPV4 and Piezo1 blocked the stretch induced intracellular Ca2+ increase. Whereas inhibition of TRPA1 blocked H2O2 evoked response in LP-ICs. Our results suggest LP-ICs of the bladder can perceive stretch or chemical stimuli via activation of TRPV2, TRPV4, Piezo1 and TRPA1 channels. LP-ICs may work together with urothelial cells for perception and transduction of mechanical or chemical signals in human-bladder mucosa.

Activation of TRPA1 in Bladder Suburothelial Myofibroblasts Counteracts TGF-β1-Induced Fibrotic Changes

“…The expression of TRPA1 channels by human bladder subu−MyoFBs was previously reported in previously reports [26,27]. Consistent with these observations, we detected the expression of TRPA1 at both the mRNA and protein level (Figure 2A,B).…”

“…It was also reported that the vast majority (>90%) of subu−MyoFBs express TRPA1 channels in humans, guinea pigs, and pigs [26,27]. However, the functional role of these TRPA1 channels at this cellular localization remains to be elucidated.…”

Sensory Neurons, PIEZO Channels and PAC1 Receptors Regulate the Mechanosensitive Release of Soluble Ectonucleotidases in the Murine Urinary Bladder Lamina Propria

“…Information about the potential role of PIEZO proteins in extracellular purinergic signaling in the bladder is very limited. For example, the downregulation of PIEZO1 resulted in a decreased stretching-induced release of ATP in cultured mouse urothelial cells [ 50 ] and interstitial cells in human bladder LP [ 25 ]. The deletion of either PIEZO1 or PIEZO2 alone in the mouse bladder urothelium had no significant effect on the release of ATP from the serosal side of the urothelium in response to the distention of the bladder mucosa by filling of the bladder at a supraphysiological flow rate [ 47 ].…”

“…The mechanosensitivity of afferent neurons in the bladder wall is modulated by endogenous neuropeptides such as the pituitary adenylate cyclase activator peptide (PACAP) [ 21 ] and neurokinin A (NKA) [ 22 ]. While studies in different systems have suggested links between stretching, the activation of PIEZO channels, the activation of neuropeptide receptors and ATP efflux [ 22 , 23 , 24 , 25 ], it is currently unknown whether such mechanisms regulate the mechanosensitive release of s-ENTDs and, hence, the degradation of ATP in the bladder LP. Therefore, the present study was designed to examine the possible interplay between sensory neurons, PIEZO channels and endogenous PACAP38 and NKA in the regulation of the constitutive and distention-induced release of s-ENTDs in the bladder LP.…”

Imatinib Mesylate Reduces Neurotrophic Factors and pERK and pAKT Expression in Urinary Bladder of Female Mice With Cyclophosphamide-Induced Cystitis

“…Receptors associated with inflammation such as transient receptor potential (Trp) channels and the tyrosine kinase receptor, platelet-derived growth factor receptor alpha (PDGFRα), are expressed in a recently identified subset of urinary interstitial cells (Koh et al, 2012;Monaghan et al, 2012;Gevaert et al, 2014b;Heppner et al, 2017;Steiner et al, 2018;Zhao et al, 2021). PDGFRα + is also expressed in multiple tissue (e.g., lung, kidney, intestine, testes, lower urinary tract, CNS) and cell types of mesenchymal origin (e.g., fibroblasts, kidney mesangial cells, astrocytes, platelets, Leydig cells, GI interstitial cells of Cajal) at varying expression throughout development (Heldin and Westermark, 1999;Andrae et al, 2008).…”