Medical College of Wisconsin
CTSICores SearchResearch InformaticsREDCap

Optogenetic urothelial cell stimulation induces bladder contractions and pelvic nerve afferent firing. Am J Physiol Renal Physiol 2023 Aug 01;325(2):F150-F163

Date

06/15/2023

Pubmed ID

37318991

DOI

10.1152/ajprenal.00035.2023

Scopus ID

2-s2.0-85164303227 (requires institutional sign-in at Scopus site)   3 Citations

Abstract

Urothelial cells, which play an essential role in 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 developed a mouse model where we can directly stimulate urothelial cells using optogenetics. We crossed a uroplakin II (UPK2) cre mouse 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 mice initiates cellular depolarization and release of ATP. Cystometry recordings demonstrated 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. Furthermore, 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. These data support 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 pathophysiological conditions.NEW & NOTEWORTHY Urothelial cells play a sensory role in bladder function. However, it has been particularly challenging to study this communication as both sensory neurons and urothelial cells express similar sensory receptors. Here we demonstrate using an optogenetic technique, that specific urothelial stimulation alone resulted in bladder contractions. This approach will have a long-lasting impact on how we study urothelial-to-sensory neuron communication and the changes that occur under disease conditions.

Author List

Robilotto GL, Yang OJ, Alom F, Johnson RD, Mickle AD

Author

Aaron D. Mickle PhD Associate Professor in the Physiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adenosine Triphosphate
Animals
Epithelial Cells
Mice
Neurons, Afferent
Optogenetics
Pelvis
Sensory Receptor Cells
Urinary Bladder
Urothelium