Activation of the mechanosensitive Ca2+ channel TRPV4 induces endothelial barrier permeability via the disruption of mitochondrial bioenergetics

Abstract

Mechanical ventilation is a life-saving intervention in critically ill patients with respiratory failure due to acute respiratory distress syndrome (ARDS), a refractory lung disease with an unacceptable high mortality rate. Paradoxically, mechanical ventilation also creates excessive mechanical stress that directly augments lung injury, a syndrome known as ventilator-induced lung injury (VILI). The specific mechanisms involved in VILI-induced pulmonary capillary leakage, a key pathologic feature of VILI are still far from resolved. The mechanoreceptor, transient receptor potential cation channel subfamily V member 4, TRPV4 plays a key role in the development of VILI through unresolved mechanism. Endothelial nitric oxide synthase (eNOS) uncoupling plays an important role in sepsis-mediated ARDS so in this study we investigated whether there is a role for eNOS uncoupling in the barrier disruption associated with TRPV4 activation during VILI. Our data indicate that the TRPV4 agonist, 4α-Phorbol 12,13-didecanoate (4αPDD) induces pulmonary arterial endothelial cell (EC) barrier disruption through the disruption of mitochondrial bioenergetics. Mechanistically, this occurs via the mitochondrial redistribution of uncoupled eNOS secondary to a PKC-dependent phosphorylation of eNOS at Threonine 495 (T495). A specific decoy peptide to prevent T495 phosphorylation reduced eNOS uncoupling and mitochondrial redistribution and preserved PAEC barrier function under 4αPDD challenge. Further, our eNOS decoy peptide was able to preserve lung vascular integrity in a mouse model of VILI. Thus, we have revealed a functional link between TRPV4 activation, PKC-dependent eNOS phosphorylation at T495, and EC barrier permeability. Reducing pT495-eNOS could be a new therapeutic approach for the prevention of VILI.

Role of Transient Receptor Potential Vanilloid 4 in Vascular Function

“…TRPV4 agonist 4α-PDD causes endothelial blebs and/or breaks in rat and mouse lungs, and increases lung endothelial permeability in a Ca 2+ -entry dependent manner ( Alvarez et al, 2006 ). Mechanically, 4α-PDD induces pulmonary arterial endothelial cell barrier disruption through the mitochondrial redistribution of uncoupled eNOS secondary to a protein kinase C-dependent phosphorylation of eNOS at Threonine 495 (T495) ( Lu et al, 2021 ). TRPV4 inhibition or deletion ameliorates endothelial permeability and fluid-induced lung injury, involving the release of Ang II and P-selectin ( Bihari et al, 2017 ).…”

Calcium Signal Profiles in Vascular Endothelium from Cdh5-GCaMP8 and Cx40-GCaMP2 Mice

“…Current evidence suggests that venous endothelium is more permeable than the arterial endothelium [40]. In this regard, endothelial TRPV4 channels have been shown to promote vascular permeability [41, 42]. Therefore, it is plausible that TRPV4 channels regulate venous endothelial perme­ability.…”

TRPV4-mediated Ca2+ influx is essential to glomerular endothelial inflammation in sepsis associated acute kidney injury

“…In the skin, TRPV4 contributes to the development and maturation of cell-cell junctions in epithelia of the skin (32). It directly interacts with β-catenin and E-cadherin, thereby results in strengthened cell-cell adhesion structures between keratinocytes and the basal membrane (21,32), thus forming a physical barrier against external environmental insults. Of note, TRPV4 is prominently expressed in endothelial cells, where it is involved in the hyper-in ammatory response and mortality associated with sepsis (9).…”