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Activation of AMP‐activated protein kinase protects endothelial barrier against reperfusion‐induced failure
Author(s) -
Assad Muhammad,
Arshad Muhammad,
Haertel Frauke V.,
Aslam Muhammad,
Fleming Ingrid,
Piper H Michael,
Noll Thomas
Publication year - 2009
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.23.1_supplement.763.13
Subject(s) - ampk , chemistry , protein kinase a , ischemia , reperfusion injury , microbiology and biotechnology , medicine , phosphorylation , biology , biochemistry
Ischemia‐reperfusion causes capillary leakage leading to edema formation and organ failure. AMPK has been shown to stabilize barrier function of endothelial cells (EC). we hypothesized that targeted activation of AMPK protects EC barrier against reperfusion‐induced failure. Methods and Results: Downregulation of AMPK by siRNA (~80%) leads to disintegration of VE‐cadherin‐mediated cell adhesion structures, alterations in actin cytoskeleton (confocal microscopy) and gap formation (GF: video‐imaging technique) between EC. Exposure of EC to ischemia (40 min, Po2<5 mmHg; pH 6.4) caused an increase in GF and a 3‐fold increase in AMPK activity (AMPK~P: AMPK phosphorylation; Western blot) after 40 min. During reperfusion (40 min, Po2=140 mm Hg; pH 7.4) GF was further increased by 307+ 9 % (P<0.05, n=5) within 40 min. In contrast, AMPK~P declined to basal level within first 10 min. of reperfusion. Addition of AICAR (AMPK activator; 5‐aminoimidizole‐4‐carboxamide riboside) at the onset of reperfusion induced AMPK~P above the endischemic level, VE‐cadherin translocation to cell borders and abolished reperfusion‐induced GF. Conclusion AMPK is involved in maintenance of endothelial barrier. Activation of AMPK at the onset of reperfusion abolishes reperfusion‐induced hyperpermeability. Hence, AMPK activation may provide a new therapeutic option to prevent reperfusion‐induced endothelial barrier failure.