Mechanosensitive Piezo1 channel activation promotes ventilator-induced lung injury via disruption of endothelial junctions in ARDS rats.

OBJECTIVE

This study aimed to investigate the role of endothelial Piezo1 in mediating ventilator-induced lung injury secondary to acute respiratory distress syndrome (ARDS).

METHODS

Rats and lung endothelial cells (ECs) were transfected with Piezo1 shRNA (shPiezo1) and Piezo1 siRNA, respectively, to knock down Piezo1. Intratracheal instillation or incubation with lipopolysaccharide (LPS) was used to establish an ARDS model, and high tidal volume (HVT) ventilation or 20% cyclic stretch (CS) was administered to simulate a two-hit injury. Lung injury, alterations in lung endothelial barrier, disruption of adherens junctions (AJs), and Ca2+ influx were assessed.

RESULTS

Lung vascular hyperpermeability was further increased in ARDS rats following HVT ventilation, which was abrogated in shPiezo1-treated rats. 20% CS led to severer rupture of AJs following LPS stimulation as indicated by immunofluorescence staining. The internalization and degradation of VE-cadherin were blocked by knockdown of Piezo1. Additionally, 20% CS induced Piezo1 activation, manifesting as elevated intracellular Ca2+ concentration in LPS-treated ECs, and subsequently increased calcium-dependent calpain activity. Pharmacological inhibition of calpain or Piezo1 knockdown prevented the loss of VE-cadherin, p120-catenin, and β-catenin in ARDS rats undergoing HVT ventilation and LPS-treated ECs exposed to 20% CS.

CONCLUSION

Excessive mechanical stretch during ARDS induces the activation of Piezo1 channel and its downstream target, calpain, via Ca2+ influx. This results in the disassembly of endothelial AJs and further facilitates lung endothelial barrier breakdown and vascular hyperpermeability.