Endothelial repair subsequent to inflammation-induced vascular damage is a poorly understood process. Inthis application, we propose a novel role for adenosine monophosphate kinase (AMPK) in promoting cadherinadhesion assembly critical for endothelial repair. We hypothesize that AMPK 1 and N-cadherin function intandem as a rapid response mechanism allowing pulmonary microvascular endothelial cells (PMVECs) torepair barrier disruptions quickly and limit increased capillary permeability. AMPK is most frequently describedas a metabolic sensor that maintains ATP levels during periods of metabolic stress. However, recent studiesindicate that AMPK also acts as a feedback mechanism that counters the destabilizing effects of elevated[Ca2+]i by promoting protein-protein interactions that strengthen cell-cell junctions. Thus, in this parallelsignaling manner, an initially barrier disruptive Ca2+ signal can secondarily activate protective mechanisms.This application expands on this idea of time and location dependent Ca2+ signaling to suggest a novel role forAMPK in Ca2+ dependent cadherin adhesion assembly and barrier repair. Our preliminary results indicate thatmembrane associated AMPK 1 subsequent to activation by inflammation-induced Ca2+ entry, activates adiscrete Ca2+ entry mechanism. This Ca2+ pathway, in contrast to inflammatory Ca2+ signaling, reorganizes thecytoskeleton crucial for N-cadherin adherens' junction assembly and endothelial cell-cell adhesion. Specifically,our preliminary data indicate capillary-derived PMVECs selectively express the AMPK 1 catalytic subunit, andpro-inflammatory challenges increase its expression in the alveolar/capillary segment in-vivo. We utilizedshRNA techniques to inhibit AMPK 1 activity and observed an attenuated increase in Ca2+ induced by theinflammatory mimetic thapsigargin suggesting AMPK activated a discrete Ca2+ pathway. Moreover, AMPKinhibition blocked wound resealing in PMVECs. AMPK 1 co-immunoprecipitates with the adherens junctionalprotein N-cadherin and co-localizes with N-cadherin to regions of cell-cell contact in PMVECs suggestingAMPK 1 and N-cadherin function in concert to regulate cytoskeletal mechanisms necessary for establishinglung capillary endothelial integrity. This proposal tests the overall HYPOTHESIS that AMPK 1 forms a functionalmembrane complex with N-cadherin essential for pulmonary endothelial barrier repair.
Specific Aims test therelated hypotheses that: [1] AMPK 1 at the membrane forms a functional complex with N-cadherin necessaryfor establishing cell-cell adhesion in PMVECs.[2] AMPK 1 activates a discrete Ca2+ entry mechanism thatpromotes N-cadherin adhesion in PMVECs. [3] Inflammatory stimuli, through Ca2+ signaling, initiate AMPK 1mediated PMVEC repair.

Public Health Relevance

Endothelial dysfunction results in disruption of cell-cell adhesions leading to vascular damage and edema formation. Our research indicates that AMPK?1 functioning in tandem with N-cadherin forms a rapid response system necessary for endothelial barrier repair. Insight gained from this research can be directly applied to development of clinically applicable vascular therapies.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Respiratory Integrative Biology and Translational Research Study Section (RIBT)
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Moore, Timothy M
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University of Alabama Birmingham
Schools of Medicine
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Jian, Ming-Yuan; Liu, Yanping; Li, Qian et al. (2016) N-cadherin coordinates AMP kinase-mediated lung vascular repair. Am J Physiol Lung Cell Mol Physiol 310:L71-85
Zhao, Xiangmin; Zhang, Wei; Xing, Dongqi et al. (2013) Endothelial cells overexpressing IL-8 receptor reduce cardiac remodeling and dysfunction following myocardial infarction. Am J Physiol Heart Circ Physiol 305:H590-8
Jiang, Shaoning; Park, Dae Won; Stigler, William S et al. (2013) Mitochondria and AMP-activated protein kinase-dependent mechanism of efferocytosis. J Biol Chem 288:26013-26
Creighton, Judy (2013) Factors controlling vascular permeability: transmitting mechanical signals. Focus on ""Mechanical induction of group V phospholipase A? causes lung inflammation and acute lung injury"". Am J Physiol Lung Cell Mol Physiol 305:L279-81
Jian, Ming-Yuan; Alexeyev, Mikhail F; Wolkowicz, Paul E et al. (2013) Metformin-stimulated AMPK-?1 promotes microvascular repair in acute lung injury. Am J Physiol Lung Cell Mol Physiol 305:L844-55
Creighton, Judy (2011) Targeting therapeutic effects: subcellular location matters. Focus on ""Pharmacological AMP-kinase activators have compartment-specific effects on cell physiology"". Am J Physiol Cell Physiol 301:C1293-5
Creighton, Judy; Jian, MingYuan; Sayner, Sarah et al. (2011) Adenosine monophosphate-activated kinase alpha1 promotes endothelial barrier repair. FASEB J 25:3356-65