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

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.

PTPN14 aggravates inflammation through promoting proteasomal degradation of SOCS7 in acute liver failure

“…and redistribution of VE-cadherin at adherens junctions is essential for the recovery of endothelial barrier function after an edemagenic insult 9 . In this study, the interaction between PTPN14 and SOCS7 was discovered in the liver, and this opened up a pathway to elucidate the immunoregulatory role of PTPN14 in ALF.…”

“…Current studies on PTPN14 were mostly focused on cancer. Evidences suggest that in LPS-induced acute lung injury (ALI), phospholipase D2 (PLD2) promotes PTPN14-mediated dephosphorylation of VE-Cadherin and redistribution of VE-cadherin at adherens junctions is essential for the recovery of endothelial barrier function after an edemagenic insult 9 . In this study, the interaction between PTPN14 and SOCS7 was discovered in the liver, and this opened up a pathway to elucidate the immunoregulatory role of PTPN14 in ALF.…”

“…A wealth of information about the role of PTPN14 in cancer is available 6 – 8 ; however, much less has been reported about its effects on the immune response. A recent study indicated that PTPN14 mediated the dephosphorylation and restoration of vascular endothelial cadherin at adherens junctions in LPS-induced acute lung injury 9 , suggesting that PTPN14 may also have a role in the regulation of inflammation.…”

NOX4 Mediates Pseudomonas aeruginosa-Induced Nuclear Reactive Oxygen Species Generation and Chromatin Remodeling in Lung Epithelium

“…Depletion of endogenous PKC δ, SPHK2, and NOX proteins in lung epithelial cells was carried out using gene-specific small interfering RNA (siRNA), as described previously [ 15 , 20 ]. Briefly, pre-designed Pkc δ , Sphk2 , Nox2 , and Nox4 or nonspecific/non-targeting siRNA (Santa Cruz Biotech, Dallas, TX, USA) were used to transfect mouse lung epithelial (MLE) 12 cells.…”

Mechanisms of Endothelial Regeneration and Vascular Repair and Their Application to Regenerative Medicine

“…VE-cadherin recycling to AJs and dephosphorylation of tyrosine phosphorylated VE-cadherin promotes junctional re-assembly and restoration of endothelial barrier function. Fu et al show that inhibition of Phospholipase D2 (PLD2) activity resulted in prolonged phosphorylation of Tyr-658 in VE-cadherin in human lung microvascular ECs during the recovery phase after thrombin challenge and thus impaired endothelial barrier recovery via inhibition of protein tyrosine phosphatase non-receptor type 14 (PTPN14) 61 . After thrombin challenge, PLD2, PTPN14, and VE-cadherin form a complex to facilitate PTPN14 dephosphorylation of VE-cadherin.…”