scholarly journals TRPV4 blockade reduces voiding frequency, ATP release, and pelvic sensitivity in mice with chronic urothelial overexpression of NGF

2019 ◽  
Vol 317 (6) ◽  
pp. F1695-F1706 ◽  
Author(s):  
Beatrice M. Girard ◽  
Susan E. Campbell ◽  
Megan Perkins ◽  
Harrison Hsiang ◽  
Katharine Tooke ◽  
...  
Keyword(s):  
Urinary Bladder ◽  
Transient Receptor Potential ◽  
Atp Release ◽  
Brefeldin A ◽  
Receptor Potential ◽  
Fold Increase ◽  
Void Volume ◽  
Bladder Function ◽  
Transient Receptor Potential Vanilloid ◽  
Transient Receptor

Transient receptor potential vanilloid family member 4 (TRPV4) transcript and protein expression increased in the urinary bladder and lumbosacral dorsal root ganglia of transgenic mice with chronic urothelial overexpression of nerve growth factor (NGF-OE). We evaluated the functional role of TRPV4 in bladder function with open-outlet cystometry, void spot assays, and natural voiding (Urovoid) assays with the TRPV4 antagonist HC-067047 (1 μM) or vehicle in NGF-OE and littermate wild-type (WT) mice. Blockade of TRPV4 at the level of the urinary bladder significantly ( P ≤ 0.01) increased the intercontraction interval (2.2-fold) and void volume (2.6-fold) and decreased nonvoiding contractions (3.0-fold) in NGF-OE mice, with lesser effects (1.3-fold increase in the intercontraction interval and 1.3-fold increase in the void volume) in WT mice. Similar effects of TRPV4 blockade on bladder function in NGF-OE mice were demonstrated with natural voiding assays. Intravesical administration of HC-067047 (1 µM) significantly ( P ≤ 0.01) reduced pelvic sensitivity in NGF-OE mice but was without effect in littermate WT mice. Blockade of urinary bladder TRPV4 or intravesical infusion of brefeldin A significantly ( P ≤ 0.01) reduced (2-fold) luminal ATP release from the urinary bladder in NGF-OE and littermate WT mice. The results of the present study suggest that TRPV4 contributes to luminal ATP release from the urinary bladder and increased voiding frequency and pelvic sensitivity in NGF-OE mice.

Abstract 358: Transient Receptor Potential Vanilloid 2 (TRPV2) contributes to myocardial contractility and hypertrophy via sarcoplasmic reticulum calcium handling

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Jack Rubinstein ◽  
Vivek P Singh ◽  
Valerie M Lasko ◽  
Sheryl E Koch ◽  
Evangelia Kranias ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Fold Increase ◽  
Calcium Handling ◽  
Heart Weight ◽  
Transient Receptor Potential Vanilloid ◽  
Cardiomyocyte Contractility ◽  
Transient Receptor

Background: TRPV2 is a Ca2+ channel that we have recently discovered in cardiomyocytes. The absence of this channel negatively impacts baseline contractility while stimulation results in a positive inotropic response. What remains to be established is the mechanism of this receptor and its role, if any, in the development of hypertrophy. Methods and Results: We obtained isolated cardiomyocytes from wild type (WT) and TRPV2-/- (KO) mice and found that the sarcoplasmic reticulum Ca2+ content and Ca2+ transients were reduced along with fractional shortening in the KO cardiomyocytes (figure, panels A, B, C). In vivo echocardiography confirmed a decrease in ejection fraction in KO mice in comparison to the WT counterparts (panel D). The relevance of these findings was examined in 6 WT and 5 KO mice subjected to transverse aortic constriction (TAC). These mice were followed by echocardiography weekly for a total of 8 weeks post TAC. At the conclusion, the hearts were obtained for histological and molecular analyses. We demonstrated that the KO mice developed less LV hypertrophy in comparison to WT (via echocardiography and by heart weight/body weight ratios) (figure, panels E and F). Importantly, there was a 5 fold increase in TRPV2 expression assessed by PCR in TAC WT hearts, compared to WT not subjected to TAC (0.72±0.10 vs. 0.13±0.04; p<0.01). This suggests a role for TRPV2 not only in contractility, but also in the development of hypertrophy. Conclusions: We have discovered a novel cardiac channel that alters Ca2+ cycling and is capable of modulating cardiomyocyte contractility and hypertrophy, which could lead to novel therapeutic options in heart failure and hypertrophy.

scholarly journals Mechanosensor transient receptor potential vanilloid member 4 (TRPV4) regulates mouse cholangiocyte secretion and bile formation

2020 ◽  
Vol 318 (2) ◽  
pp. G277-G287
Author(s):  
Qin Li ◽  
Charles Kresge ◽  
Kristy Boggs ◽  
Julie Scott ◽  
Andrew Feranchak
Keyword(s):  
Fluid Flow ◽  
Bile Flow ◽  
Transient Receptor Potential ◽  
Atp Release ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Bile Formation ◽  
Transport Pathways ◽  
Transient Receptor

Mechanosensitive signaling has emerged as a mechanism for the regulation of cholangiocyte transport and bile formation. The mechanical effect of fluid-flow, or shear, at the apical membrane of cholangiocytes regulates secretion through a process involving increases in [Ca2+]i and activation of Ca2+-activated Cl− channels. However, the initiating steps translating shear force to increases in intracellular calcium concentration ([Ca2+]i) are unknown. Transient receptor potential vanilloid member 4 (TRPV4), a nonselective cation channel present in the apical membrane of cholangiocytes, has been proposed as a potential mechanosensor. The aim of the present studies was to determine the potential role of TRPV4 in initiating mechanosensitive signaling in response to fluid-flow in cholangiocytes. TRPV4 expression was confirmed in both small and large mouse cholangiocytes. Exposure of cells to either fluid flow or specific TRPV4 pharmacological agonists rapidly increased both [Ca2+]i and membrane cation currents. Both flow- and agonist-stimulated currents displayed identical biophysical properties and were inhibited in the presence of TRPV4 antagonists or in cells after transfection with TRPV4 small interfering RNA. Transfection of mouse cholangiocytes with a TRPV4-enhanced green fluorescent protein construct increased the expression of TRPV4 and the magnitude of flow-stimulated currents. A specific TRPV4 agonist significantly increased the biliary concentration of ATP and bile flow in live mice when administered intravenously and increased ATP release from cholangiocyte monolayers when applied exogenously. The findings are consistent with a model in which activation of cholangiocyte TRPV4 translates shear force into an acute rise in membrane cation permeability, [Ca2+]i, ATP release, and bile flow. Understanding the role of mechanosensitive transport pathways may provide novel insights to modulate bile flow for the treatment of cholestatic liver disorders. NEW & NOTEWORTHY These studies functionally characterize TRPV4 as a mechanosensitive channel in mouse cholangiocytes. By mediating a rapid rise in intracellular Ca2+, necessary for Ca2+-dependent secretion, TRPV4 represents a mechanosensor responsible for translating fluid flow into intracellular signaling and biliary secretion. Furthermore, intravenous infusion of a specific TRPV4 agonist increases bile flow in live mice. Understanding the role of TRPV4 in mechanosensitive transport pathways may provide novel insights to modulate bile flow during cholestasis.

PAR-2 activation enhances weak acid-induced ATP release through TRPV1 and ASIC sensitization in human esophageal epithelial cells

2015 ◽  
Vol 309 (8) ◽  
pp. G695-G702 ◽  
Author(s):  
Liping Wu ◽  
Tadayuki Oshima ◽  
Jing Shan ◽  
Hiroo Sei ◽  
Toshihiko Tomita ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Transient Receptor Potential ◽  
Atp Release ◽  
Receptor Potential ◽  
Weak Acid ◽  
Transient Receptor Potential Vanilloid ◽  
Esophageal Epithelial Cells ◽  
Transient Receptor ◽  
Esophageal Hypersensitivity ◽  
Interfering Rna

Esophageal visceral hypersensitivity has been proposed to be the pathogenesis of heartburn sensation in nonerosive reflux disease. Protease-activated receptor-2 (PAR-2) is expressed in human esophageal epithelial cells and is believed to play a role in inflammation and sensation. PAR-2 activation may modulate these responses through adenosine triphosphate (ATP) release, which is involved in transduction of sensation and pain. The transient receptor potential vanilloid receptor 1 (TRPV1) and acid-sensing ion channels (ASICs) are both acid-sensitive nociceptors. However, the interaction among these molecules and the mechanisms of heartburn sensation are still not clear. We therefore examined whether ATP release in human esophageal epithelial cells in response to acid is modulated by TRPV1 and ASICs and whether PAR-2 activation influences the sensitivity of TRPV1 and ASICs. Weak acid (pH 5) stimulated the release of ATP from primary human esophageal epithelial cells (HEECs). This effect was significantly reduced after pretreatment with 5-iodoresiniferatoxin (IRTX), a TRPV1-specific antagonist, or with amiloride, a nonselective ASIC blocker. TRPV1 and ASIC3 small interfering RNA (siRNA) transfection also decreased weak acid-induced ATP release. Pretreatment of HEECs with trypsin, tryptase, or a PAR-2 agonist enhanced weak acid-induced ATP release. Trypsin treatment led to the phosphorylation of TRPV1. Acid-induced ATP release enhancement by trypsin was partially blocked by IRTX, amiloride, or a PAR-2 antagonist. Conversely, acid-induced ATP release was augmented by PAR-2 activation through TRPV1 and ASICs. These findings suggested that the pathophysiology of heartburn sensation or esophageal hypersensitivity may be associated with the activation of PAR-2, TRPV1, and ASICs.

Transient Receptor Potential Vanilloid 4 Dependent Calcium Influx and ATP Release in Mouse Esophageal Keratinocytes

2011 ◽  
Vol 140 (5) ◽  
pp. S-625
Author(s):  
Hiroshi Mihara ◽  
Ammar Boudaka ◽  
Toshiro Sugiyama ◽  
Yoshinori Moriyama ◽  
Makoto Tominaga
Keyword(s):  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Atp Release ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Transient Receptor

scholarly journals Active Intestinal Calcium Transport in the Absence of Transient Receptor Potential Vanilloid Type 6 and Calbindin-D9k

Endocrinology ◽  
2008 ◽  
Vol 149 (6) ◽  
pp. 3196-3205 ◽  
Author(s):  
Bryan S. Benn ◽  
Dare Ajibade ◽  
Angela Porta ◽  
Puneet Dhawan ◽  
Matthias Hediger ◽  
...  
Keyword(s):  
Vitamin D ◽  
Calcium Transport ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Fold Increase ◽  
Transient Receptor Potential Vanilloid ◽  
Low Calcium Diet ◽  
Calbindin D9k ◽  
Intestinal Calcium Transport ◽  
Transient Receptor

To study the role of the epithelial calcium channel transient receptor potential vanilloid type 6 (TRPV6) and the calcium-binding protein calbindin-D9k in intestinal calcium absorption, TRPV6 knockout (KO), calbindin-D9k KO, and TRPV6/calbindin-D9k double-KO (DKO) mice were generated. TRPV6 KO, calbindin-D9k KO, and TRPV6/calbindin-D9k DKO mice have serum calcium levels similar to those of wild-type (WT) mice (∼10 mg Ca2+/dl). In the TRPV6 KO and the DKO mice, however, there is a 1.8-fold increase in serum PTH levels (P &lt; 0.05 compared with WT). Active intestinal calcium transport was measured using the everted gut sac method. Under low dietary calcium conditions there was a 4.1-, 2.9-, and 3.9-fold increase in calcium transport in the duodenum of WT, TRPV6 KO, and calbindin-D9k KO mice, respectively (n = 8–22 per group; P &gt; 0.1, WT vs. calbindin-D9k KO, and P &lt; 0.05, WT vs. TRPV6 KO on the low-calcium diet). Duodenal calcium transport was increased 2.1-fold in the TRPV6/calbindin-D9k DKO mice fed the low-calcium diet (P &lt; 0.05, WT vs. DKO). Active calcium transport was not stimulated by low dietary calcium in the ileum of the WT or KO mice. 1,25-Dihydroxyvitamin D3 administration to vitamin D-deficient null mutant and WT mice also resulted in a significant increase in duodenal calcium transport (1.4- to 2.0-fold, P &lt; 0.05 compared with vitamin D-deficient mice). This study provides evidence for the first time using null mutant mice that significant active intestinal calcium transport occurs in the absence of TRPV6 and calbindin-D9k, thus challenging the dogma that TRPV6 and calbindin-D9k are essential for vitamin D-induced active intestinal calcium transport.

scholarly journals Transient receptor potential vanilloid 4-dependent calcium influx and ATP release in mouse and rat gastric epithelia

2016 ◽  
Vol 22 (24) ◽  
pp. 5512 ◽  
Author(s):  
Hiroshi Mihara ◽  
Nobuhiro Suzuki ◽  
Ammar Abdullkader Boudaka ◽  
Jibran Sualeh Muhammad ◽  
Makoto Tominaga ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Atp Release ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Transient Receptor
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