N-((1S)-1-{[4-((2S)-2-{[(2,4-Dichlorophenyl)sulfonyl]amino}-3-hydroxypropanoyl)-1-piperazinyl]carbonyl}-3-methylbutyl)-1-benzothiophene-2-carboxamide (GSK1016790A), a Novel and Potent Transient Receptor Potential Vanilloid 4 Channel Agonist Induces Urinary Bladder Contraction and Hyperactivity: Part I

Abstract

The transient receptor potential (TRP) vanilloid 4 (TRPV4) member of the TRP superfamily has recently been implicated in numerous physiological processes. In this study, we describe a small molecule TRPV4 channel activator, (N-, which we have used as a valuable tool in investigating the role of TRPV4 in the urinary bladder. GSK1016790A elicited Ca 2ϩ influx in mouse and human TRPV4-expressing human embryonic kidney (HEK) cells (EC 50 values of 18 and 2.1 nM, respectively), and it evoked a dose-dependent activation of TRPV4 whole-cell currents at concentrations above 1 nM. In contrast, the TRPV4 activator 4␣-phorbol 12,13-didecanoate (4␣-PDD) was 300-fold less potent than GSK1016790A in activating TRPV4 currents. TRPV4 mRNA was detected in urinary bladder smooth muscle (UBSM) and urothelium of TRPV4 ϩ/ϩ mouse bladders. Western blotting and immunohistochemistry demonstrated protein expression in both the UBSM and urothelium that was absent in TRPV4 Ϫ/Ϫ bladders. TRPV4 activation with GSK1016790A contracted TRPV4 ϩ/ϩ mouse bladders in vitro, both in the presence and absence of the urothelium, an effect that was undetected in TRPV4 Ϫ/Ϫ bladders. Consistent with the effects on TRPV4 HEK whole-cell currents, 4␣-PDD demonstrated a weak ability to contract bladder strips compared with GSK1016790A. In vivo, urodynamics in TRPV4 ϩ/ϩ and TRPV4 Ϫ/Ϫ mice revealed an enhanced bladder capacity in the TRPV4 Ϫ/Ϫ mice. Infusion of GSK1016790A into the bladders of TRPV4 ϩ/ϩ mice induced bladder overactivity with no effect in TRPV4 Ϫ/Ϫ mice. Overall TRPV4 plays an important role in urinary bladder function that includes an ability to contract the bladder as a result of the expression of TRPV4 in the UBSM.Transient receptor potential (TRP) vanilloid 4 (TRPV4), a member of the TRP superfamily of cation channels, has been implicated in a number of physiological processes, including osmoregulation (Liedtke and Friedman, 2003;Mizuno et al., 2003), hearing (Tabuchi et al., 2005), thermal and mechaniThis work was supported by GlaxoSmithKline Pharmaceuticals. Article, publication date, and citation information can be found at

Inhibition of the cation channel TRPV4 improves bladder function in mice and rats with cyclophosphamide-induced cystitis

“…At this point, we cannot exclude that inhibition of TRPV4 in other cell types contributes to the observed effects of HC-067047 on bladder function. In the bladder, TRPV4 is also expressed in the detrusor muscle layer, albeit at an ∼20-fold lower expression level than in urothelium (13), and in endothelial cells surrounding blood vessels. Moreover, TRPV4 expression has been documented in dorsal root ganglion neurons innervating the viscera and has been implicated in tonicity-induced neurogenic inflammation and release of substance P and calcitonin gene-related peptide (CGRP) from bladder tissue (29,30).…”

“…Recent research has identified TRPV4 as an important regulator of normal bladder function (12)(13)(14)(15)(16)25), but its involvement in the development of cystitis and the associated changes in bladder function was unknown. In this article, we show that the development of reduced functional bladder capacity and pollakisuria after cyclophosphamide treatment is strongly impaired in Trpv4 −/− mice, despite clear signs of severe hemorrhagic cystitis.…”

“…Recent research has shown that TRPV4, a cation channel of the transient receptor potential (TRP) superfamily (10,11), is highly expressed in the urothelial cell layer of the bladder, where it is implicated in sensing the filling state of the bladder (12)(13)(14)(15)(16). Importantly, Trpv4 −/− mice exhibited a lower voiding frequency and larger voided volume than wild type (WT) mice did.…”

Function of Transient Receptor Potential Cation Channel Subfamily V Member 4 (TRPV4) as a Mechanical Transducer in Flow-sensitive Segments of Renal Collecting Duct System

“…Using fluorescence ratiometric imaging of the Ca 2ϩ -sensitive probe, fura-2, [Ca 2ϩ ] i was monitored and presented as the ratio F 340 /F 380 (or [Ca 2ϩ ] i in summary figures) as described previously (3,4). To activate TRPV4 selectively, we took advantage of the TRPV4 agonist, GSK101, to demonstrate specific activation of TRPV4 (19,24). As shown in Fig.…”

TRPV4 channels stimulate Ca 2 + -induced Ca 2+ release in astrocytic endfeet and amplify neurovascular coupling responses

“…1D, a. Exposure of brain slices to the selective TRPV4 agonist, GSK1016790A (hereafter GSK; 100 nM) (30), induced rapid, high-amplitude Ca 2+ oscillations in endfeet, increasing oscillation frequency by 417% ± 113% (Fig. 1C, b).…”