Endothelial focal adhesion kinase contributes to intestinal microvascular leakage during ischemia/reperfusion injury

Abstract

Ischemia/reperfusion (I/R) injury triggers a series of inflammatory responses in the microcirculation characterized by vascular leakage and leukocyte activation leading to organ dysfunction. In this study, we examine whether focal adhesion kinase (FAK) contributes to endothelial barrier dysfunction in response to I/R in splanchnic tissues. Using an in vivo model of intestinal I/R injury, we showed that the increase of microvascular leakage induced by I/R injury was greatly attenuated in endothelial specific, tamoxifen inducible, FAK knockout animals as well as wild type animals given pharmacological inhibition of FAK with PF‐573228. Using murine intestinal endothelial cells, we performed electric cell‐substrate impedance sensing (ECIS) assays with or without FAK inhibitor in the presence of H2O2. Results showed that FAK inhibition significantly attenuated endothelial barrier dysfunction induced by H2O2. Western blot analysis showed that H2O2 promoted FAK phosphorylation in a time course similar to that of endothelial barrier dysfunction. Confocal imaging analysis demonstrated that H2O2 increases the disruption of junctional proteins. The effect was blocked by FAK inhibitor. Taken together, the results suggested that FAK plays an important role in mediating intestinal vascular leakage during I/R injury.Support or Funding InformationNIH HL120954, VA BX000799