Optogenetic urothelial cell stimulation induces bladder contractions and pelvic nerve afferent firing

Abstract

Urothelial cells, which play an essential role in the barrier function, are also thought to play a sensory role in bladder physiology by releasing signaling molecules in response to sensory stimuli that act upon adjacent sensory neurons. However, it is challenging to study this communication due to the overlap in receptor expression and proximity of urothelial cells to sensory neurons. To overcome this challenge, we have developed a mouse model where we can directly stimulate urothelial cells using optogenetics. We have crossed a uroplakin II-cre mouse (UPK2-Cre) with a mouse that expresses the light-activated cation channel, Channelrhodopsin-2 (ChR2), in the presence of cre-expression. Optogenetic stimulation of urothelial cells cultured from UPK2-ChR2 initiates cellular depolarization and release of adenosine triphosphate. Cystometry recordings demonstrate that optical stimulation of urothelial cells increases bladder pressure and pelvic nerve activity. Increases in bladder pressure persisted, albeit to a lesser extent, when the bladder was excised in an in vitro preparation. The P2X receptor antagonist, PPADS, significantly reduced optically evoked bladder contractions in vivo and ex vivo. Further, corresponding nerve activity was also inhibited with PPADS. Our data suggest that urothelial cells can initiate robust bladder contractions via sensory nerve signaling or contractions through local signaling mechanisms. This data supports a foundation of literature demonstrating communication between sensory neurons and urothelial cells. Importantly, with further use of these optogenetic tools, we hope to scrutinize this signaling mechanism, its importance for normal micturition and nociception, and how it may be altered in pathophysiologic conditions.

Blocking P2Y2 purinergic receptor prevents the development of lipopolysaccharide-induced acute respiratory distress syndrome

“…Notably, our current study does not exclude the potential contribution of P2X receptors in ARDS. Indeed, we observed similar effects of non-selective P2Y receptors antagonist suramin ( 60 , 61 ) or P2 receptors antagonist PPADS ( 62 , 63 ) on reducing cytokine concentrations and microvascular plasma leakage measurements in the therapeutic regime experiments. In addition, we found that expression of P2x receptors including P2x4 and P2x7 at mRNA level increased in macrophages of LPS-treated mice.…”

How does the lower urinary tract contribute to bladder sensation? ICI‐RS 2023

“…There is accumulating evidence that urothelial chemical transduction mediates increases in bladder wall strain and raised afferent firing. 30,36 Various neurotransmitters, including adenosine triphosphate (ATP), acetylcholine (ACh), nitric oxide (NO•), and prostaglandins released from the urothelium have been proposed to activate and/ or modulate the firing of bladder innervating sensory nerves or underlying bladder wall cells. 30 Receptors for these urothelial neurotransmitters are expressed on bladder-innervating sensory afferents, interstitial cells of the lamina propria, and the urothelium, providing the cellular architecture for autocrine or paracrine signaling of urothelial mediators to potentially influence bladder sensation and function.…”

Optical EUS Activation to Relax Sensitized Micturition Response

“…Recently, optogenetics has been applied in research for micturition control to modulate its complex neural networks. This includes targeting the central nervous system [17][18][19][20][21], the peripheral nervous system [22][23][24], and the bladder [25][26][27]. However, most of the results so far have focused on controlling bladder activity.…”