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

Mengmeng Zhao,Jiaxin Liu,Jiliang Wen,Lei Liu,Xiulin Zhang,Shulu Zu,Ning Ding,Nan Ge,Guoqing Chen,Zhenghao Chen,Wenzhen Wang,Wei Song

doi:10.3389/fphys.2021.762847

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.

Highlights

Interstitial cells (ICs) in the bladder have attracted much research attention in recent years (Andersson and Mccloskey, 2014; Koh et al, 2018)
An immunohistochemistrybased study (Gevaert et al, 2014) on human bladder tissue revealed that alpha-smooth muscle actin (α-SMA) + Vim + ICs were located mainly in the upper lamina propria (ULP) and packed densely in the sub-urothelial layer (Figure 1A). α-SMA-ICs were located at the deeper lamina propria (DLP) as well as between or within the detrusor (Figure 1B), which suggested that most of our cultured ICs were from the ULP
We cultured ICs from the bladder mucosa, so we could not exclude the presence of DLP-ICs

Summary

Introduction

Interstitial cells (ICs) in the bladder have attracted much research attention in recent years (Andersson and Mccloskey, 2014; Koh et al, 2018). Based on their location, two populations of ICs in the bladder have been characterized: LP-ICs, which are between the urothelium and detrusor and ICs in the detrusor (detrusor-ICs) (Andersson and Mccloskey, 2014; Gevaert et al, 2014). DLP-ICs are Vim + /αSMA-/PDGFRα + /c-kit-. Detrusor-ICs have a similar phenotype to that of DLP-ICs (Monaghan et al, 2012; Gevaert et al, 2014; Steiner et al, 2018)

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