Functional characterization of transient receptor potential channels in mouse urothelial cells.
The bladder urothelium is currently believed to be a sensory structure, contributing to mechano- and chemosensation in the bladder. Transient receptor potential (TRP) cation channels act as polymodal sensors and may underlie some of the receptive properties of urothelial cells. However, the exact TRP channel expression profile of urothelial cells is unclear. In this study, we have performed a systematic analysis of the molecular and functional expression of various TRP channels in mouse urothelium. Urothelial cells from control and trpv4-/- mice were isolated, cultured (12-48 h), and used for quantitative real-time PCR, immunocytochemistry, calcium imaging, and whole cell patch-clamp experiments. At the mRNA level, TRPV4, TRPV2, and TRPM7 were the most abundantly expressed TRP genes. Immunohistochemistry showed a clear expression of TRPV4 in the plasma membrane, whereas TRPV2 was more prominent in the cytoplasm. TRPM7 was detected in the plasma membrane as well as cytoplasmic vesicles. Calcium imaging and patch-clamp experiments using TRP channel agonists and antagonists provided evidence for the functional expression of TRPV4, TRPV2, and TRPM7 but not of TRPA1, TRPV1, and TRPM8. In conclusion, we have demonstrated functional expression of TRPV4, TRPV2, and TRPM7 in mouse urothelial cells. These channels may contribute to the (mechano)sensory function of the urothelial layer and represent potential targets for the treatment of bladder dysfunction.
Everaerts
Wouter
W
Department of Molecular Cell Biology, Laboratory Ion Channel Research, Campus Gasthuisberg, Katholieke Universiteit Leuven, Leuven, Belgium. wouter.everaerts@med.kuleuven.be
Vriens
Joris
J
Owsianik
Grzegorz
G
Appendino
Giovanni
G
Voets
Thomas
T
De Ridder
Dirk
D
Nilius
Bernd
B
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D008564:Membrane Potentials; D049990:Membrane Transport Modulators / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D018408:Patch-Clamp Techniques; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D050053:TRPM Cation Channels / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism; D013997:Time Factors; D050051:Transient Receptor Potential Channels / Q000172:deficiency / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D001743:Urinary Bladder / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019459:Urothelium / Q000378:metabolism
D015220:Calcium Channels; D049990:Membrane Transport Modulators; D012333:RNA, Messenger; D050053:TRPM Cation Channels; D050916:TRPV Cation Channels; D050051:Transient Receptor Potential Channels; C485717:Trpv2 protein, mouse; C486576:Trpv4 protein, mouse; C421903:Trpm7 protein, mouse