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

ABSTRACTOne of the most rapid (less than 4 ms) transmembrane cellular mechanotransduction events involves activation of transient receptor potential vanilloid 4 (TRPV4) ion channels by mechanical forces transmitted across cell surface β1 integrin receptors on endothelial cells, and the transmembrane solute carrier family 3 member 2 (herein denoted CD98hc, also known as SLC3A2) protein has been implicated in this response. Here, we show that β1 integrin, CD98hc and TRPV4 all tightly associate and colocalize in focal adhesions where mechanochemical conversion takes place. CD98hc knockdown inhibits TRPV4-mediated calcium influx induced by mechanical forces, but not by chemical activators, thus confirming the mechanospecificity of this signaling response. Molecular analysis reveals that forces applied to β1 integrin must be transmitted from its cytoplasmic C terminus via the CD98hc cytoplasmic tail to the ankyrin repeat domain of TRPV4 in order to produce ultrarapid, force-induced channel activation within the focal adhesion.

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

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00176.2019 ◽

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.

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

AJP Renal Physiology ◽

10.1152/ajprenal.00147.2019 ◽

2019 ◽

Vol 317 (6) ◽

pp. F1695-F1706 ◽

Cited By ~ 1

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.

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

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00162.2015 ◽

2015 ◽

Vol 309 (8) ◽

pp. G695-G702 ◽

Cited By ~ 14

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.

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Angiotensin II induces membrane trafficking of natively expressed transient receptor potential vanilloid type 4 channels in hypothalamic 4B cells

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00224.2014 ◽

2014 ◽

Vol 307 (8) ◽

pp. R945-R955 ◽

Cited By ~ 13

Author(s):

Ashwini Saxena ◽

Martha Bachelor ◽

Yong H. Park ◽

Flavia R. Carreno ◽

T. Prashant Nedungadi ◽

...

Keyword(s):

Angiotensin Ii ◽

Membrane Trafficking ◽

Transient Receptor Potential ◽

Calcium Influx ◽

Src Kinase ◽

Receptor Potential ◽

Family Type ◽

Transient Receptor Potential Vanilloid ◽

Ang Ii ◽

Transient Receptor

Transient receptor potential vanilloid family type 4 (TRPV4) channels are expressed in central neuroendocrine neurons and have been shown to be polymodal in other systems. We previously reported that in the rodent, a model of dilutional hyponatremia associated with hepatic cirrhosis, TRPV4 expression is increased in lipid rafts from the hypothalamus and that this effect may be angiotensin dependent. In this study, we utilized the immortalized neuroendocrine rat hypothalamic 4B cell line to more directly test the effects of angiotensin II (ANG II) on TRPV4 expression and function. Our results demonstrate the expression of corticotropin-releasing factor (CRF) transcripts, for sex-determining region Y (SRY) (male genotype), arginine vasopressin (AVP), TRPV4, and ANG II type 1a and 1b receptor in 4B cells. After a 1-h incubation in ANG II (100 nM), 4B cells showed increased TRPV4 abundance in the plasma membrane fraction, and this effect was prevented by the ANG II type 1 receptor antagonist losartan (1 μM) and by a Src kinase inhibitor PP2 (10 μM). Ratiometric calcium imaging experiments demonstrated that ANG II incubation potentiated TRPV4 agonist (GSK 1016790A, 20 nM)-induced calcium influx (control 18.4 ± 2.8% n = 5 and ANG II 80.5 ± 2.4% n = 5). This ANG II-induced increase in calcium influx was also blocked by 1 μM losartan and 10 μM PP2 (losartan 26.4 ± 3.8% n = 5 and PP2 19.7 ± 3.9% n = 5). Our data suggests that ANG II can increase TRPV4 channel membrane expression in 4B cells through its action on AT1R involving a Src kinase pathway.

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Transgene-free remote magnetothermal regulation of adrenal hormones

Science Advances ◽

10.1126/sciadv.aaz3734 ◽

2020 ◽

Vol 6 (15) ◽

pp. eaaz3734 ◽

Cited By ~ 6

Author(s):

Dekel Rosenfeld ◽

Alexander W. Senko ◽

Junsang Moon ◽

Isabel Yick ◽

Georgios Varnavides ◽

...

Keyword(s):

Heat Dissipation ◽

Transient Receptor Potential ◽

Calcium Influx ◽

Hormone Secretion ◽

Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Precise Control ◽

Endogenous Expression ◽

Transient Receptor ◽

Electrical Signaling

The field of bioelectronic medicines seeks to modulate electrical signaling within peripheral organs, providing temporally precise control of physiological functions. This is usually accomplished with implantable devices, which are often unsuitable for interfacing with soft and highly vascularized organs. Here, we demonstrate an alternative strategy for modulating peripheral organ function, which relies on the endogenous expression of a heat-sensitive cation channel, transient receptor potential vanilloid family member 1 (TRPV1), and heat dissipation by magnetic nanoparticles (MNPs) in remotely applied alternating magnetic fields. We use this approach to wirelessly control adrenal hormone secretion in genetically intact rats. TRPV1-dependent calcium influx into the cells of adrenal cortex and medulla is sufficient to drive rapid release of corticosterone and (nor)epinephrine. As altered levels of these hormones have been correlated with mental conditions such as posttraumatic stress disorder and major depression, our approach may facilitate the investigation of physiological and psychological impacts of stress.

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Blue Light Irradiation Induces Human Keratinocyte Cell Damage via Transient Receptor Potential Vanilloid 1 (TRPV1) Regulation

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/8871745 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Ju Ah. Yoo ◽

Eunbi Yu ◽

See-Hyoung Park ◽

Sae Woong Oh ◽

Kitae Kwon ◽

...

Keyword(s):

Cell Proliferation ◽

Blue Light ◽

Transient Receptor Potential ◽

Calcium Influx ◽

Receptor Potential ◽

Light Irradiation ◽

Transient Receptor Potential Vanilloid ◽

Skin Cells ◽

Tnf Α ◽

Transient Receptor

Although blue light has been reported to affect skin cells negatively, little is known about its action mechanisms in skin cells. Therefore, we investigated the role of the transient receptor potential vanilloid 1 (TRPV1) in blue light-induced effects on human keratinocytes and its underlying mechanisms. Blue light decreased cell proliferation and upregulated TRPV1 expression. Blue light also suppressed the epidermal growth factor receptor- (EGFR-) mediated signaling pathway by reducing the protein levels of EGFR and suppressing the EGFR/PI3K/AKT/GSK3β/FoxO3a pathway. The blue light-induced effect in cell proliferation was reversed by TRPV1 siRNA, but not capsazepine, a TRPV1-specific antagonist. In addition, blue light irradiation increased the production of reactive oxygen species (ROS) and tumor necrosis factor-α (TNF-α). Blue light irradiation also increased both phosphorylation levels of TRPV1 and calcium influx. The blue light-induced increase in production of ROS and TNF-α was reversed by capsazepine. Furthermore, the blue light-induced increase in production of TNF-α was attenuated by SP600125 or PDTC. These findings show that blue light regulates cell survival and production of ROS and TNF-α; its effects are mediated via TRPV1. Specifically, the effects of blue light on cell proliferation are mediated by upregulating TRPV1, a negative regulator of EGFR-FoxO3a signaling. Blue light-induced production of ROS and TNF-α is also mediated through increased calcium influx via TRPV1 activation.

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