Modulation of P2Y 2 R‐Dependent Vascular Barrier Function: Focal Adhesion Kinase

We found that stimulation of P2Y 2 receptor (P2Y 2 R) induced transient increase in venule permeability as 5‐folds greater than baseline in C57BL mouse cremaster skeletal muscle. Given that integrin mediates the P2Y 2 receptor signaling, we hypothesized that focal adhesion complex would be involved in signaling pathway to regulate P2Y 2 R‐induced hyperpermeability. To test the hypothesis, we isolated and cultured microvascular endothelial cells derived from both wild‐type mice and P2Y 2 R knockout mice as in vitro models to assess the focal adhesion kinase signaling mechanism underlying P2Y 2 R‐induced hyperpermeability. We found that endothelial permeability was 1.27‐fold (1.27 ± 0.09, n=5, P<0.05 ) greater vs the baseline by 10 −5 M UTP stimulation for 10 min in vitro, supporting the in vivo results. The increased permeability response to 10 −5 M UTP was inhibited by focal adhesion kinase inhibitor PF‐228 (10 −5 M). Phosphorylation of focal adhesion kinase at tyrosine‐397 increased (1.48 ± 0.11, n=3, P<0.05 compared with the basal level) in response to 10 −5 M UTP stimulation for 10 min in the wild type microvascular endothelial cells while there was no change in P2Y 2 R knockout microvascular endothelial cells. The findings demonstrates that focal adhesion kinase plays an important role in the regulation of P2Y 2 R‐dependent hyperpermeability. Support or Funding Information Missouri Sate University Faculty Research Grant