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Involvement of FAK and Src in microvascular hyperpermeability caused by fibrinogen‐gamma C‐terminal fragments
Author(s) -
Guo Xiaohua,
Yuan Sarah Y,
Wu Mack H
Publication year - 2013
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.27.1_supplement.896.9
Subject(s) - proto oncogene tyrosine protein kinase src , focal adhesion , rhoa , chemistry , phosphorylation , vascular permeability , microbiology and biotechnology , signal transduction , biology , biochemistry , endocrinology
Fibrinogen degradation products have been associated with microvascular dysfunction during traumatic injury. We previously reported that fibrinogen‐gamma C‐terminal fragments (gC) was capable of causing microvascular leakage via integrin‐mediated and RhoA‐dependent pathway. In this study, we further explored the potential roles of focal adhesion kinase (FAK) and Src in the gC‐induced microvascular hyperpermeability. Albumin permeability was measured using Intravital microscopy in mouse mesenteric microvasculature. The fluid permeability was assessed by measuring capillary filtration coefficient ( K fc ) in isolated and perfused mouse lungs. In addition, transcellular electric resistance (TER) was measured in cultured endothelial cell monolayers as an indicator of barrier function. The results showed that inhibition of FAK with PF‐573228 or Src with PP2 significantly attenuated gC‐induced microvascular hyperpermeability in vivo. Correspondingly, Western blot analyses revealed that gC promoted phosphorylation of FAK (Y397) and Src (Y416) in time‐dependent fashion comparable to that of gC‐induced microvascular permeability. FAK or Src gene silencing and pharmacological inhibition greatly attenuated gC‐elicited reduction in TER in endothelial monolayers. Furthermore, inhibition of FAK blocked gC‐induced Src phosphorylation, indicating FAK activation as a signaling event upstream from Src activation. Additionally, we found that gc was able to cause adherence junction responses characterized by VE‐cadherin phosphorylation and dissociation between VE‐cadherin and b‐catenin coupled with junction disorganization. These responses were attenuated during inhibition of FAK or Src. Taken together, the data suggest that the FAK‐Src pathway plays an important role in mediating microvascular endothelial barrier dysfunction caused by gC stimulation. Supported by NIH RO1HL‐096640 and HL‐070752.