Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2005805 | Peptides | 2016 | 9 Pages |
Abstract
Adropin is a peptide encoded by the energy homeostasis associated gene (Enho) and plays a critical role in the regulation of lipid metabolism, insulin sensitivity, and endothelial function. Little is known of the effects of adropin in the brain and whether this peptide modulates ischemia-induced blood-brain barrier (BBB) injury. Here, we used an in vitro BBB model of rat brain microvascular endothelial cells (RBE4) and hypothesized that adropin would reduce endothelial permeability during ischemic conditions. To mimic ischemic conditions in vitro, RBE4 cell monolayers were subjected to 16Â h hypoxia/low glucose (HLG). This resulted in a significant increase in paracellular permeability to FITC-labeled dextran (40Â kDa), a dramatic upregulation of vascular endothelial growth factor (VEGF), and the loss of junction proteins occludin and VE-cadherin. Notably, HLG also significantly decreased Enho expression and adropin levels. Treatment of RBE4 cells with synthetic adropin (1, 10 and 100Â ng/ml) concentration-dependently reduced endothelial permeability after HLG, but this was not mediated through protection to junction proteins or through reduced levels of VEGF. We found that HLG dramatically increased myosin light chain 2 (MLC2) phosphorylation in RBE4 cells, which was significantly reduced by adropin treatment. We also found that HLG significantly increased Rho-associated kinase (ROCK) activity, a critical upstream effector of MLC2 phosphorylation, and that adropin treatment attenuated that effect. These data indicate that treatment with adropin reduces endothelial cell permeability after HLG insult by inhibition of the ROCK-MLC2 signaling pathway. These promising findings suggest that adropin protects against endothelial barrier dysfunction during ischemic conditions.
Keywords
HLGRBE4ZO-1MLCPHIF-1αOGDeNOSMLCKFITC-dextranMLC2HBMECsERK1/2VE-cadherinAdropinAktTight junctionELISAEnzyme-linked immunosorbent assayCNSMyosin light chain 2myosin light chain kinaseBBBRat brain microvascular endothelial cellsHuman brain microvascular endothelial cellsendothelial nitric oxide synthasecentral nervous systemapparent permeability coefficientHypoxia inducible factor-1alphaVascular endothelial growth factorVascular Endothelial Growth Factor (VEGF)Myosin light chain phosphataseBlood-brain barrierOxygen-glucose deprivationParacellular permeabilityZonula occludens-1HypoxiaPappTight junction proteinsprotein kinase BAdherens junctionvascular endothelial cadherinRho-associated kinaseextracellular signal-regulated kinases 1 and 2Rock
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Authors
Changjun Yang, Kelly M. DeMars, Kimberly E. Hawkins, Eduardo Candelario-Jalil,