The role of ATP signalling in response to mechanical stimulation studied in T24 cells using new microphysiological tools

Abstract

The capacity to store urine and initiate voiding is a valued characteristic of the human urinary bladder. To maintain this feature, it is necessary that the bladder can sense when it is full and when it is time to void. The bladder has a specialized epithelium called urothelium that is believed to be important for its sensory function. It has been suggested that autocrine ATP signalling contributes to this sensory function of the urothelium. There is well‐established evidence that ATP is released via vesicular exocytosis as well as by pannexin hemichannels upon mechanical stimulation. However, there are still many details that need elucidation and therefore there is a need for the development of new tools to further explore this fascinating field. In this work, we use new microphysiological systems to study mechanostimulation at a cellular level: a mechanostimulation microchip and a silicone‐based cell stretcher. Using these tools, we show that ATP is released upon cell stretching and that extracellular ATP contributes to a major part of Ca2+ signalling induced by stretching in T24 cells. These results contribute to the increasing body of evidence for ATP signalling as an important component for the sensory function of urothelial cells. This encourages the development of drugs targeting P2 receptors to relieve suffering from overactive bladder disorder and incontinence.

Stimuli‐Responsive Biomaterials: Scaffolds for Stem Cell Control

“…[134] Conductive polymers, commonly PPy, have been used to directly mechanically stimulate cells in "lab on a chip" type approaches and induce increases in low piezoelectrical activity of internal calcium concentration of stimulated cells. [135,136] This approach of using the conductive polymer's unique actuation properties in 3D scaffolds has recently been explored; PPy coated poly(lactic-co-glycolic acid) (PLGA) fibers underwent cyclical swelling and shrinking when an electrical signal was applied to the scaffold (biphasic waveform 0.2 to −1 V, 0.05 Hz for 600 s every 24 h for 3 consecutive days) which delivered omnidirectional strain (6-8%) and flow through the scaffold pores to the seeded iPSC, in addition to the electrical stimulation ( Figure 10A,B). This dual mechanical and electrical stimulation was observed to significantly downregulate Oct4, indicating differentiation of the iPSC, and upregulation of cardiomyocyte specific genes NKX2.5 and GATA4 both with and without stimulation on the PPy/PLGA scaffolds.…”

Pulmonary neuroendocrine cells: physiology, tissue homeostasis and disease

“…Furthermore, mechanical stretch enhances 5-HT release from NEBs in rabbit models, further suggesting that PNECs might be mechanosensitive and are possibly capable of transducing mechanical information into neurotransmission ( Pan et al, 2006 ). Another candidate mediator for PNEC mechanotransduction could be adenosine triphosphate (ATP), as known in various tissues ( Kringelbach et al, 2015 ; Guan et al, 2018 ). In an ex vivo lung slice model, depolarization of PNECs with high K + releases the ATP stored in DCVs ( De Proost et al, 2009 ).…”

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

“…In vivo , changes in intravesical pressure or bladder wall tension are physiologically relevant mechanical stimuli for the urothelium. To simulate these stimuli in vitro , common strategies include stretching of urothelial cells cultured on coverslips using various customized devices ( Miyamoto et al, 2014 ; Guan et al, 2018 ) or exposing urothelial cells to high hydrostatic pressure ( Olsen et al, 2011 ). For example, custom designed chambers, attached to an extension device, were used to stretch urothelial cells in one study ( Miyamoto et al, 2014 ).…”