Phospholipase D2 restores endothelial barrier function by promoting PTPN14-mediated VE-cadherin dephosphorylation

Panfeng Fu,Ramaswamy Ramchandran,Mark Shaaya,Longshuang Huang,David L Ebenezer,Ying Jiang,Yulia Komarova,Stephen M Vogel,Asrar B Malik,Richard D Minshall,Guangwei Du,Nicholas K Tonks,Viswanathan Natarajan

doi:10.1074/jbc.ra119.011801

Abstract

Increased permeability of vascular lung tissues is a hallmark of acute lung injury and is often caused by edemagenic insults resulting in inflammation. Vascular endothelial (VE)-cadherin undergoes internalization in response to inflammatory stimuli and is recycled at cell adhesion junctions during endothelial barrier re-establishment. Here, we hypothesized that phospholipase D (PLD)-generated phosphatidic acid (PA) signaling regulates VE-cadherin recycling and promotes endothelial barrier recovery by dephosphorylating VE-cadherin. Genetic deletion of PLD2 impaired recovery from protease-activated receptor-1-activating peptide (PAR-1-AP)-induced lung vascular permeability and potentiated inflammation in vivo In human lung microvascular endothelial cells (HLMVECs), inhibition or deletion of PLD2, but not of PLD1, delayed endothelial barrier recovery after thrombin stimulation. Thrombin stimulation of HLMVECs increased co-localization of PLD2-generated PA and VE-cadherin at cell-cell adhesion junctions. Inhibition of PLD2 activity resulted in prolonged phosphorylation of Tyr-658 in VE-cadherin during the recovery phase 3 h post-thrombin challenge. Immunoprecipitation experiments revealed that after HLMVECs are thrombin stimulated, PLD2, VE-cadherin, and protein-tyrosine phosphatase nonreceptor type 14 (PTPN14), a PLD2-dependent protein-tyrosine phosphatase, strongly associate with each other. PTPN14 depletion delayed VE-cadherin dephosphorylation, reannealing of adherens junctions, and barrier function recovery. PLD2 inhibition attenuated PTPN14 activity and reversed PTPN14-dependent VE-cadherin dephosphorylation after thrombin stimulation. Our findings indicate that PLD2 promotes PTPN14-mediated dephosphorylation of VE-cadherin and that redistribution of VE-cadherin at adherens junctions is essential for recovery of endothelial barrier function after an edemagenic insult.

Highlights

Increased permeability of vascular lung tissues is a hallmark of acute lung injury and is often caused by edemagenic insults resulting in inflammation
These results demonstrate that PLD2/phosphatidic acid (PA) signaling is essential for proper endothelial cell (EC) barrier recovery and protein-tyrosine phosphatase nonreceptor type 14 (PTPN14) is a novel PA-regulated proteintyrosine phosphatases (PTPs) that mediates Vascular endothelial (VE)-cadherin de-phosphorylation and restoration at adhesion junctions (AJ)
Pld2Ϫ/Ϫ mice showed significantly higher bronchoalveolar lavage (BAL) fluid protein content (Fig. 1C), and a small but significant increase in the IL-6 level in BAL fluids compared with WT, and Pld1Ϫ/Ϫ mice after a 3-h PAR-1–AP challenge (Fig. 1F) with no significant difference in BAL tumor necrosis factor (TNF)␣ levels (Fig. 1G)

Summary

Introduction

Increased permeability of vascular lung tissues is a hallmark of acute lung injury and is often caused by edemagenic insults resulting in inflammation.

Results

Conclusion