Role of TRPV4 Channel in Vasodilation and Neovascularization

Background: Pulmonary hypertension (PH) is a degenerative disorder that is characterized by elevated vascular resistance and pulmonary arterial pressure (PAP). Endothelial transient receptor potential vanilloid 4 (TRPV4 EC ) ion channels represent an important Ca 2+ influx signaling mechanism that promotes vasodilation of small pulmonary arteries (PAs). Scaffolding protein caveolin-1 (Cav-1) has been shown to precipitate with TRPV4 channels in pulmonary endothelial cells in culture. Hypothesis: We hypothesized that the endothelial Cav-1-TRPV4 channel signaling in small PAs lowers PAP, and is impaired in PH. Methods: Inducible endothelium-specific KO mice for TRPV4 channel or Cav-1 were used to study the role of Cav-1-TRPV4 signaling in the regulation of resting PAP. Endothelium-specific P2Y2 receptor KO mice were used to test if Cav-1 provides a signaling scaffold for purinergic activation of TRPV4 EC channels. Endothelial Cav-1-TRPV4 signaling was assessed in PAs from two PH mouse models and PH patients. The role of NADPH oxidase (NOX1)- and inducible nitric oxide synthase (iNOS)-mediated peroxynitrite (PN), an oxidant molecule, in impairing Cav-1-TRPV4 signaling in PH was evaluated using NOX1-/- and iNOS-/- mice and pharmacological inhibitors. Results: We show that endothelial Cav-1-TRPV4 signaling in small PAs lowers resting PAP, and protects against the pathogenesis of PH. Endothelial Cav-1 provides a signaling scaffold for the activation of TRPV4 channels by endogenous purinergic receptor signaling. Moreover, TRPV4 EC channel activity and Cav-1-TRPV4 signaling are impaired in small PAs from two mouse models of PH and PH patients. Elevated levels of NOX1 and iNOS enzymes in caveolae resulted in PN formation close to Cav-1 in PH. Elevated PN targeted Cav-1 to lower Cav-1-TRPV4 signaling, thereby contributing to impaired vasodilation and increased PAP. Pharmacological inhibition of NOX1, iNOS, or PN rescued TRPV4 EC channel activity and vasodilation in PH. Conclusion: This study provides novel evidence that endothelial Cav-1-TRPV4 signaling lowers PAP and is impaired in PH. Inhibiting NOX1 or iNOS activity, or lowering endothelial PN levels may represent a novel strategy for restoring TRPV4 EC channel activity, vasodilation, and PAP.

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Local Peroxynitrite Impairs Endothelial Transient Receptor Potential Vanilloid 4 Channels and Elevates Blood Pressure in Obesity

Circulation ◽

10.1161/circulationaha.119.043385 ◽

2020 ◽

Vol 141 (16) ◽

pp. 1318-1333 ◽

Cited By ~ 9

Author(s):

Matteo Ottolini ◽

Kwangseok Hong ◽

Eric L. Cope ◽

Zdravka Daneva ◽

Leon J. DeLalio ◽

...

Keyword(s):

Nitric Oxide ◽

Blood Pressure ◽

Transient Receptor Potential ◽

Regulatory Protein ◽

Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Channel Activity ◽

Transient Receptor ◽

Trpv4 Channel

Background: Impaired endothelium-dependent vasodilation is a hallmark of obesity-induced hypertension. The recognition that Ca 2+ signaling in endothelial cells promotes vasodilation has led to the hypothesis that endothelial Ca 2+ signaling is compromised during obesity, but the underlying abnormality is unknown. In this regard, transient receptor potential vanilloid 4 (TRPV4) ion channels are a major Ca 2+ influx pathway in endothelial cells, and regulatory protein AKAP150 (A-kinase anchoring protein 150) enhances the activity of TRPV4 channels. Methods: We used endothelium-specific knockout mice and high-fat diet–fed mice to assess the role of endothelial AKAP150-TRPV4 signaling in blood pressure regulation under normal and obese conditions. We further determined the role of peroxynitrite, an oxidant molecule generated from the reaction between nitric oxide and superoxide radicals, in impairing endothelial AKAP150-TRPV4 signaling in obesity and assessed the effectiveness of peroxynitrite inhibition in rescuing endothelial AKAP150-TRPV4 signaling in obesity. The clinical relevance of our findings was evaluated in arteries from nonobese and obese individuals. Results: We show that Ca 2+ influx through TRPV4 channels at myoendothelial projections to smooth muscle cells decreases resting blood pressure in nonobese mice, a response that is diminished in obese mice. Counterintuitively, release of the vasodilator molecule nitric oxide attenuated endothelial TRPV4 channel activity and vasodilation in obese animals. Increased activities of inducible nitric oxide synthase and NADPH oxidase 1 enzymes at myoendothelial projections in obese mice generated higher levels of nitric oxide and superoxide radicals, resulting in increased local peroxynitrite formation and subsequent oxidation of the regulatory protein AKAP150 at cysteine 36, to impair AKAP150-TRPV4 channel signaling at myoendothelial projections. Strategies that lowered peroxynitrite levels prevented cysteine 36 oxidation of AKAP150 and rescued endothelial AKAP150-TRPV4 signaling, vasodilation, and blood pressure in obesity. Peroxynitrite-dependent impairment of endothelial TRPV4 channel activity and vasodilation was also observed in the arteries from obese patients. Conclusions: These data suggest that a spatially restricted impairment of endothelial TRPV4 channels contributes to obesity-induced hypertension and imply that inhibiting peroxynitrite might represent a strategy for normalizing endothelial TRPV4 channel activity, vasodilation, and blood pressure in obesity.

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Activation of endothelial TRPV4 channels mediates flow-induced dilation in human coronary arterioles: role of Ca2+ entry and mitochondrial ROS signaling

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00717.2011 ◽

2012 ◽

Vol 302 (3) ◽

pp. H634-H642 ◽

Cited By ~ 80

Author(s):

Aaron H. Bubolz ◽

Suelhem A. Mendoza ◽

Xiaodong Zheng ◽

Natalya S. Zinkevich ◽

Rongshan Li ◽

...

Keyword(s):

Coronary Artery Disease ◽

Coronary Artery ◽

Transient Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Human Coronary Artery ◽

Mitochondrial Ros ◽

Artery Disease ◽

Trpv4 Channel ◽

Coronary Arterioles

In human coronary arterioles (HCAs) from patients with coronary artery disease, flow-induced dilation is mediated by a unique mechanism involving the release of H2O2 from the mitochondria of endothelial cells (ECs). How flow activates ECs to elicit the mitochondrial release of H2O2 remains unclear. Here, we examined the role of the transient receptor potential vanilloid type 4 (TRPV4) channel, a mechanosensitive Ca2+-permeable cation channel, in mediating ROS formation and flow-induced dilation in HCAs. Using RT-PCR, Western blot analysis, and immunohistochemical analysis, we detected the mRNA and protein expression of TRPV4 channels in ECs of HCAs and cultured human coronary artery ECs (HCAECs). In HCAECs, 4α-phorbol-12,13-didecanoate (4α-PDD), a selective TRPV4 agonist, markedly increased (via Ca2+ influx) intracellular Ca2+ concentration. In isolated HCAs, activation of TRPV4 channels by 4α-PDD resulted in a potent concentration-dependent dilation, and the dilation was inhibited by removal of the endothelium and by catalase, a H2O2-metabolizing enzyme. Fluorescence ROS assays showed that 4α-PDD increased the production of mitochondrial superoxide in HCAECs. 4α-PDD also enhanced the production of H2O2 and superoxide in HCAs. Finally, we found that flow-induced dilation of HCAs was markedly inhibited by different TRPV4 antagonists and TRPV4-specific small interfering RNA. In conclusion, the endothelial TRPV4 channel is critically involved in flow-mediated dilation of HCAs. TRPV4-mediated Ca2+ entry may be an important signaling event leading to the flow-induced release of mitochondrial ROS in HCAs. Elucidation of this novel TRPV4-ROS pathway may improve our understanding of the pathogenesis of coronary artery disease and/or other cardiovascular disorders.

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ROLE OF TRPV4 CHANNEL SIGNALING IN SHEAR STRESS RESPONSES

The FASEB Journal ◽

10.1096/fasebj.2020.34.s1.04328 ◽

2020 ◽

Vol 34 (S1) ◽

pp. 1-1

Author(s):

Kevin M. Aria

Keyword(s):

Shear Stress ◽

Stress Responses ◽

Trpv4 Channel

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Human TRPV4 channel splice variants revealed a key role of ankyrin domains in multimerization and trafficking. VOLUME 281 (2006) PAGES 1580-1586

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)56608-x ◽

2006 ◽

Vol 281 (13) ◽

pp. 8996

Author(s):

Maite Arniges ◽

José M. Fernández-Fernández ◽

Nadine Albrecht ◽

Michael Schaefer ◽

Miguel A. Valverde

Keyword(s):

Splice Variants ◽

Trpv4 Channel

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Mitochondria regulate TRPV4 mediated release of ATP

10.22541/au.161941863.34069176/v1 ◽

2021 ◽

Author(s):

Xun Zhang ◽

Matthew Lee ◽

Charlotte Buckley ◽

Calum Wilson ◽

John McCarron

Keyword(s):

Purinergic Receptors ◽

Experimental Approach ◽

Channel Blocker ◽

Atp Release ◽

Cyclopiazonic Acid ◽

Inositol Triphosphate ◽

Resistance Arteries ◽

Synthase Inhibitor ◽

Trpv4 Channel

Background and Purpose Ca influx via TRPV4 triggers Ca release from the IP-sensitive internal store to generate repetitive oscillations. While mitochondria are acknowledged regulators of IP-mediated Ca release, how TRPV4-mediated Ca signals are regulated by mitochondria is unknown. We show that depolarised mitochondria switch TRPV4 signalling from relying on Ca-induced Ca release at IP receptors, to being independent of Ca influx and instead mediated by ATP release via pannexins. Experimental Approach TRPV4 evoked Ca signals were individually examined in hundreds of cells in the endothelium of rat mesenteric resistance arteries using the indicator Cal520. Key ResultsTRPV4 activation with GSK1016790A(GSK) generated repetitive Ca oscillations that required Ca influx. However, when the mitochondrial membrane potential was depolarised, by the uncoupler CCCP or complex I inhibitor rotenone, TRPV4 activation generated large propagating, multicellular, Ca waves in the absence of external Ca. The ATP synthase inhibitor oligomycin did not potentiate TRPV4 mediated Ca signals. GSK-evoked Ca waves, when mitochondria were depolarised, were blocked by the TRPV4 channel blocker HC067047, the SERCA inhibitor cyclopiazonic acid, the phospholipase C (PLC) blocker U73122 and the inositol triphosphate receptor (IP R) blocker caffeine. The Ca waves were also inhibited by the extracellular ATP blockers suramin and apyrase and the pannexin blocker probenecid. Conclusion and Implications These results highlight a previously unknown role of mitochondria in shaping TRPV4 mediated Ca signalling by facilitating ATP release. When mitochondria are depolarised, TRPV4-mediated release of ATP via pannexin channels activates plasma membrane purinergic receptors to trigger IP evoked Ca release.

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