Functional Transient Receptor Potential Vanilloid 1 is Expressed in Human Urothelial Cells
is companion of
Abstract
Purpose:
We investigated the expression and functional status of TRPV1 receptor in human urothelial cells.
Material and Methods:
Human urothelium was cultured and TRPV1 receptor expression was studied by immunocytochemistry and reverse transcriptase-polymerase chain reaction. The influence of inflammatory mediators on TRPV1 mRNA levels was also studied. Functional assays (cobalt uptake measurements and whole cell voltage clamp records) were used to study the response of urothelial cells to capsaicin, temperature, low pH and inflammatory mediators. Capsaicin induced adenosine triphosphate release from urothelial cells was assessed by bioluminescence.
Results:
TRPV1 protein and mRNA were detected in human urothelial cells and mRNA more than tripled in the presence of inflammatory mediators. Nerve growth factor treatment alone did not affect TRPV1 mRNA expression. Capsaicin (100 nM and 1 μM) and heat (41C and 45C) evoked cobalt uptake and inflammatory mediators lowered the temperature threshold for TRPV1 activation to 37C. Capsaicin (1 μM) induced TRPV1 desensitization to further applications of the agonist. In whole cell patch clamp experiments 1 μM capsaicin and a heat ramp from 37C to 50C caused inward currents. The same concentration of capsaicin induced the release of about 7 fmol adenosine triphosphate per mg.
Conclusions:
TRPV1 receptors expressed by human urothelial cells respond to capsaicin and thermal stimuli. Capsaicin evoked release of adenosine triphosphate suggests that human urothelial TRPV1 is involved in the afferent branch of the micturition reflex. Inflammatory mediators decrease the TRPV1 thermal threshold of activation to body temperature and increase its expression. This finding may be relevant for symptoms associated with cystitis.
References
- 1 : TRPV1: a therapeutic target for novel analgesic drugs?. TIMM2006; 12: 545. Google Scholar
- 2 : The vanilloid receptor TRPV1: 10 years from channel cloning to antagonist proof-of-concept. Nat Rev Drug Discov2007; 6: 357. Google Scholar
- 3 : Vanilloid receptor-1 is essential for inflammatory thermal hyperalgesia. Nature2000; 405: 183. Google Scholar
- 4 : TRPV1 is essential for the generation of noxious bladder input and bladder overactivity in cystitis. J Urol2007; 177: 1537. Link, Google Scholar
- 5 : Capsaicin receptor VR1 and ATP-gated ion channel P2X3 in human urinary bladder. BJU Int2001; 87: 774. Google Scholar
- 6 : Vanilloid receptor 1 expression in the rat urinary tract. Neuroscience2002; 109: 787. Google Scholar
- 7 : The cloned capsaicin receptor integrates multiple pain-producing stimuli. Neuron1998; 21: 531. Google Scholar
- 8 : Vanilloid receptor expression suggests a sensory role for urinary bladder epithelial cells. PNAS2001; 98: 13396. Google Scholar
- 9 : The capsaicin receptor: a heat-activated ion channel in the pain pathway. Nature1997; 389: 816. Crossref, Medline, Google Scholar
- 10 : Functional TRP and ASIC-like channels in cultured urothelial cells from the rat. Am J Physiol Renal Physiol2009; 296: F892. Google Scholar
- 11 : Functional TRPV4 channels and absence of capsaicin-evoked currents in freshly-isolated, guinea-pig urothelial cells. Channels (Austin)2009; 3: 156. Google Scholar
- 12 : Immunohistochemical evidence of vanilloid receptor 1 in normal human urinary bladder. Eur Urol2004; 46: 792. Google Scholar
- 13 Charrua A, Avelino A, Nagy I et al: Functional properties of TRPV1 expressed in human urothelial cells. Presented at annual meeting of International Continence Society, Christchurch, New Zealand, November 27, 2006. Google Scholar
- 14 :
Culture of human urothelium . In: Culture of Epithelial Cells. Edited by . New York: Wiley-Liss2002: 381. chapt 12. Google Scholar - 15 : TRPV3 is a temperature-sensitive vanilloid receptor-like protein. Nature2002; 418: 186. Google Scholar
- 16 : Decreased sensory receptors P2X3 and TRPV1 in suburothelial nerve fibers following intradetrusor injections of botulinum toxin for human detrusor overactivity. J Urol2005; 174: 977. Link, Google Scholar
- 17 : DRG11 immunohistochemical expression during embryonic development in the mouse. Dev Dyn2007; 236: 2653. Google Scholar
- 18 : Inflammatory mediators convert anandamide into a potent activator of the vanilloid type 1 transient receptor potential receptor in nociceptive primary sensory neurons. Neuroscience2005; 136: 539. Google Scholar
- 19 : Where is TRPV1 expressed in the bladder, do we see the real channel?. Naunyn Schmiedebergs Arch Pharmacol2009; 379: 421. Google Scholar
- 20 : Proton activation does not alter antagonist interaction with the capsaicin-binding pocket of TRPV1. Mol Pharmacol2005; 68: 1524. Google Scholar
- 21 : TRPV1 (vanilloid receptor) in the urinary tract: expression, function and clinical applications. Naunyn Schmiedebergs Arch Pharmacol2006; 373: 287. Google Scholar
- 22 : Transcription of rat TRPV1 utilizes a dual promoter system that is positively regulated by nerve growth factor. J Neurochem2007; 101: 212. Google Scholar
- 23 : p38 MAPK activation by NGF in primary sensory neurons after inflammation increases TRPV1 levels and maintains heat hyperalgesia. Neuron2002; 36: 57. Google Scholar
- 24 : Urinary bladder hyporeflexia and reduced pain-related behaviour in P2X3-deficient mice. Nature2000; 407: 1011. Crossref, Medline, Google Scholar
- 25 : Augmented stretch activated adenosine triphosphate release from bladder uroepithelial cells in patients with interstitial cystitis. J Urol2001; 166: 1951. Link, Google Scholar
