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Adenosine monophosphate-activated kinase alpha1 promotes endothelial barrier repair.

ABSTRACT: 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?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?1 activity is required for the formation of PMVEC cell-cell networks in a prorepair environment and for monolayer resealing after wounding. Decreasing AMPK?1 expression reduces barrier resistance in PMVEC monolayers, results consistent with a role for AMPK?1 in cell-cell adhesion. AMPK?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?1 in Ca(2+) influx-mediated signaling and wound repair in the endothelium.

SUBMITTER: Creighton J

PROVIDER: S-EPMC3177581 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature

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Adenosine monophosphate-activated kinase alpha1 promotes endothelial barrier repair.

Creighton Judy J Jian MingYuan M Sayner Sarah S Alexeyev Mikhail M Insel Paul A PA

FASEB journal : official publication of the Federation of American Societies for Experimental Biology 20110616 10

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 AMPKα1 catalytic subunit, pharmacological and short hairpin RNA-m ...[more]

PMID: 21680893

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Project description:OBJECTIVE:Our goal was to determine the mechanism by which mitochondrial oxidative stress impairs collateral growth in the heart. APPROACH AND RESULTS:Rats were treated with rotenone (mitochondrial complex I inhibitor that increases reactive oxygen species production) or sham-treated with vehicle and subjected to repetitive ischemia protocol for 10 days to induce coronary collateral growth. In control rats, repetitive ischemia increased flow to the collateral-dependent zone; however, rotenone treatment prevented this increase suggesting that mitochondrial oxidative stress compromises coronary collateral growth. In addition, rotenone also attenuated mitochondrial complex I activity and led to excessive mitochondrial aggregation. To further understand the mechanistic pathway(s) involved, human coronary artery endothelial cells were treated with 50 ng/mL vascular endothelial growth factor, 1 µmol/L rotenone, and rotenone/vascular endothelial growth factor for 48 hours. Vascular endothelial growth factor induced robust tube formation; however, rotenone completely inhibited this effect (P<0.05 rotenone versus vascular endothelial growth factor treatment). Inhibition of tube formation by rotenone was also associated with significant increase in mitochondrial superoxide generation. Immunoblot analyses of human coronary artery endothelial cells with rotenone treatment showed significant activation of adenosine monophosphate activated kinase (AMPK)-? and inhibition of mammalian target of rapamycin and p70 ribosomal S6 kinase. Activation of AMPK-? suggested impairments in energy production, which was reflected by decrease in O2 consumption and bioenergetic reserve capacity of cultured cells. Knockdown of AMPK-? (siRNA) also preserved tube formation during rotenone, suggesting the negative effects were mediated by the activation of AMPK-?. Conversely, expression of a constitutively active AMPK-? blocked tube formation. CONCLUSIONS:We conclude that activation of AMPK-? during mitochondrial oxidative stress inhibits mammalian target of rapamycin signaling, which impairs phenotypic switching necessary for the growth of blood vessels.

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Adenosine monophosphate-activated kinase alpha1 promotes endothelial barrier repair.

Publications

Adenosine monophosphate-activated kinase alpha1 promotes endothelial barrier repair.

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