2. Academic Validation
  3. PLD2 deletion alleviates disruption of tight junctions in sepsis-induced ALI by regulating PA/STAT3 phosphorylation pathway

PLD2 deletion alleviates disruption of tight junctions in sepsis-induced ALI by regulating PA/STAT3 phosphorylation pathway

  • Int Immunopharmacol. 2023 Jan:114:109561. doi: 10.1016/j.intimp.2022.109561.
Tiantian Qian 1,  Boyang Qi 2,  Yuxin Fei 1,  Jun Li 3,  Liqing Luo 4,  Bingjie Lv 1,  Yutong Song 1,  Shurui Sheng 1,  Wenhan Xiao 1,  Xiao Huang 5,  Xiaozhi Wang 6
Affiliations

Affiliations

  • 1 Department of Intensive Care Unit, Binzhou Medical University Hospital, Binzhou, Shandong, China.
  • 2 Cardiac Surgical Intensive Care Unit, Yantai yuhuangding Hospital of Qingdao University Medical College, Yantai, Shandong, China.
  • 3 Department of Pulmonary and Critical Care Medicine, Yantai Affiliated Hospitol of Binzhou Medical University, Yantai, Shandong, China.
  • 4 Department of Hematology, Binzhou Medical University Hospital, Binzhou, Shandong, China.
  • 5 Department of Intensive Care Unit, Binzhou Medical University Hospital, Binzhou, Shandong, China. Electronic address: huangxiao9008@163.com.
  • 6 Department of Intensive Care Unit, Binzhou Medical University Hospital, Binzhou, Shandong, China. Electronic address: hxicuwxz@163.com.
PMID: 36700766 DOI: 10.1016/j.intimp.2022.109561
Abstract

Background: Increased inflammatory exudation caused by endothelium and endothelial junction damage is a typical pathological feature of acute respiratory distress syndrome/acute lung injury (ARDS/ALI). Previous studies have shown that Phospholipase D2 (PLD2) can increase the inflammatory response and has a close relationship with the severity of sepsis-induced ALI and the mortality of sepsis, but its mechanism is unknown. This study explored the effect and mechanism of PLD2 deletion on the structure and function of endothelial tight junction (TJ) in lipopolysaccharide (LPS)-induced ALI.

Methods: We used C57BL/6 mice (wild-type and PLD2 knockout (PLD2-/-)) and human umbilical vein endothelial cell (HUVEC) models of sepsis-ALI. The pathological changes were evaluated by hematoxylin-eosin staining. Pulmonary vascular permeability was detected using wet-dry ratio, fluorescein isothiocyanate (FITC)-dextran, FITC-albumin, and immunoglobulin M concentration of bronchoalveolar lavage fluid. FITC-dextran and trans-endothelial electrical resistance assay were used to evaluate endothelial permeability on LPS-stimulated HUVECs. The mRNA expressions of TJ proteins were detected by real-time quantitative polymerase chain reaction. Then, protein levels were detected through Western blot analysis and immunofluorescence. The content of phosphatidic acid (PA), a downstream product of PLD2, was detected using an enzyme-linked immunosorbent assay kit.

Results: PLD2 deficiency not only alleviated lung histopathological changes and improved pulmonary vascular permeability but also increased the survival rate of ALI mice. Knockout of PLD2 or treatment with the PLD2 inhibitor can reduce the damage of endothelial TJ proteins, namely, claudin5, occludin and zonula occludens protein-1, in sepsis-ALI mice and LPS-stimulated HUVECs. The level of the PLD2 catalytic product PA increased in LPS-stimulated HUVECs, and exogenous PA can reduce the TJ protein expression and increase signal transducer and activator of transcription 3 (STAT3) phosphorylation in vitro. Inhibition of STAT3 phosphorylation attenuated PA-induced degradation of endothelial TJs.

Conclusion: PLD2 knockout or inhibition may protect against LPS-induced lung injury by regulating the PA/STAT3 phosphorylation/endothelial TJ axis.

Keywords

Acute respiratory distress syndrome/acute lung injury; Phospholipase D2; STAT3; Sepsis; Tight junction proteins.

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