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IIntracellular BiP/GRP78 Mediates Endothelial Cell Permeability and Inflammation Associated with Acute Lung Injury
Author(s) -
Leonard Antony,
Su PeiYi,
Millar Michelle,
Dubey Nikhil,
Yule David,
Rahman Arshad,
Fazal Fabeha
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.lb610
Subject(s) - proinflammatory cytokine , endoplasmic reticulum , microbiology and biotechnology , intracellular , unfolded protein response , thrombin , extracellular , endothelial stem cell , inflammation , chemistry , vascular permeability , endothelium , immunology , biology , biochemistry , endocrinology , platelet , in vitro
The role of endoplasmic reticulum (ER) chaperone and signaling regulator BiP/GRP78 in acute inflammatory injury, particularly in the context of lung endothelium, is poorly defined. Recent studies have shown that BiP/GRP78 not only resides in the ER but is present in extra‐ER regions as well, and perform different functions. In this study, we monitored the effect of intracellular versus cell surface BiP/GRP78 in EC permeability and inflammation associated with acute lung injury (ALI). Studies were performed using SubAB, a holoenzyme that cleaves and specifically inactivates intracellular BiP/GRP78 versus SubA, which cleaves and inactivates only the cell surface BiP/GRP78. Stimulation of endothelial cell (EC) with proinflammatory mediator thrombin showed a characteristic time‐dependent change in TER (trans‐endothelial resistance), a real time measurement of EC permeability, which was protected in the presence of SubAB but not in the presence of SubA and its inactive mutant SubA A272 B. In order to further dissect the mechanism of thrombin‐mediated EC permeability, we determined the role of BiP/GRP78 in mediating Ca 2+ signaling, a critical determinant of EC permeability. Interestingly, SubAB significantly reduced thrombin‐induced Ca 2+ release from the ER stores as well as Ca 2+ entry from the extracellular medium; however SubA and SubA A272 B failed to mediate the above response. Furthermore, mechanistic analysis revealed that thrombin‐induced activation of STIM‐1 (Stromal Interaction Molecule 1) via Y361 phosphorylation, which stimulates Ca 2+ entry across the plasma membrane, was blocked in the presence of SubAB. In addition, thrombin‐induced phosphorylation of eNOS at serine 1177 as well as the association of phosphorylated eNOS with p190GAP, which is a major mechanism responsible for AJ disassembly resulting in increased EC permeability, was significantly blocked by SubAB. Interestingly, thrombin‐induced inflammatory responses were not affected in the presence of SubA as opposed to SubAB. Together, these data highlight a novel role of intracellular BiP/GRP78 in mediating EC barrier disruption and inflammation associated with ALI Support or Funding Information NIH (HL096907 and HL130870) This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .