Adenosine monophosphate-activated kinase α1 promotes endothelial barrier repair

The vascular endothelium responds to damage through activation of multiple signaling events that restore cell-cell adhesion and vascular integrity. However, the molecular mechanisms that integrate these events are not clearly defined. Herein, we identify a previously unexpected role for adenosine monophosphate-activated protein kinase (AMPK) in pulmonary microvascular endothelial cell (PMVEC) repair. PMVECs selectively express the AMPK alpha 1 catalytic subunit, pharmacological and short hairpin RNA-mediated inhibition of which attenuates Ca(2+) entry in these cells induced by the inflammatory Ca(2+)-signaling mimetic thapsigargin. We find that AMPK alpha 1 activity is required for the formation of PMVEC cell-cell networks in a prorepair environment and for monolayer resealing after wounding. Decreasing AMPK alpha 1 expression reduces barrier resistance in PMVEC monolayers, results consistent with a role for AMPK alpha 1 in cell-cell adhesion. AMPK alpha 1 colocalizes and coimmunoprecipitates with the adherens junction protein N-cadherin and cofractionates with proteins selectively expressed in caveolar membranes. Assessment of permeability, by measuring the filtration coefficient (K(f)) in isolated perfused lungs, confirmed that AMPK activation contributes to barrier repair in vivo. Our findings thus provide novel evidence for AMPK alpha 1 in Ca(2+) influx-mediated signaling and wound repair in the endothelium.-Creighton, J., Jian, M., Sayner, S., Alexeyev, M., Insel, P. A. Adenosine monophosphate-activated kinase alpha 1 promotes endothelial barrier repair. FASEB J. 25, 3356-3365 (2011). www.fasebj.org