Premium
PMN mediated endothelial cell TRPM2 activation regulates neutrophil trafficking and lung vascular permeability
Author(s) -
Mittal Manish,
Nepal Saroj,
Tiruppathi Chinnaswamy,
Malik Asrar B
Publication year - 2017
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.31.1_supplement.995.2
Subject(s) - trpm2 , transient receptor potential channel , vascular permeability , endothelial stem cell , chemistry , small interfering rna , microbiology and biotechnology , biology , receptor , biochemistry , endocrinology , in vitro , transfection , gene
TRPM2 (Transient receptor potential melastatin‐2) is a cation channel that mediates Ca 2+ entry in response to intracellular ADP ribose (ADPR) generated during oxidative stress. We tested the hypothesis that Reactive Oxygen Species (ROS) released by polymorphonuclear leukocytes (PMNs) during sepsis activate endothelial TRPM2 and induce trans‐endothelial PMN migration and cause lung vascular injury. To investigate the role of endothelial TRPM2 in PMN transmigration, we generated tamoxifen inducible endothelial cell‐restricted TRPM2 knockout ( Trpm2 ΔEC−/− ) mice. Lung vascular permeability and PMN transmigration following LPS challenge (10 mg/Kg) did not increase in these mice. Human lung microvascular endothelial cells (HLMVECs) treated with TRPM2‐siRNA or poly ADP ribose polymerase 1 (PARP1)‐siRNA showed significantly reduced Ca 2+ entry in response to activated PMNs (PMN‐to‐EC ratio of 5:1). PMNs isolated from gp91phox −/− mice or WT mice treated with DPI (10 μM) significantly reduced Ca 2+ entry in ECs as compared to WT PMNs. ECs treated with PARP1‐siRNA also showed significantly reduced ADPR generation in response to H 2 O 2 stimulation. Overexpression of the ADPR insensitive TRPM2 mutant channel (C1008A) in HLMVECs significantly suppressed the H 2 O 2 induced Ca 2+ entry. In vivo forced expression of the TRPM2 mutant channel or silencing of PARP‐1 protected against LPS‐induced increase in lung vascular permeability and PMN transmigration in mice. We conclude that endothelial Ca 2+ entry following activation of TRPM2 in PMNs disrupts endothelial barrier, thereby promotes lung vascular injury. Support or Funding Information RO1 HL 077806, RO1 HL 122157