title: Activation of AMPK attenuates lipopolysaccharide-impaired integrity and function of blood-brain barrier in human brain microvascular endothelial cells.
abstract: The blood-brain barrier (BBB), formed by specialized brain endothelial cells that are interconnected by tight junctions, strictly regulates paracellular permeability to maintain an optimal extracellular environment for brain homeostasis. Lipopolysaccharide (LPS) is known to alter the integrity of the BBB in sepsis, although the underlying mechanism remains unknown. The aim of this study was to elucidate the molecular mechanisms underlying the disruption of the BBB in LPS-induced sepsis and to determine whether the activation of AMP-activated protein kinase (AMPK) prevents LPS-induced BBB dysfunction. The exposure of human brain microvascular endothelial cells (HBMECs) to LPS (1 μg/ml) for 4 to 24h a week dramatically increased the permeability of the BBB in parallel with the lowered expression levels of occludin and claudin-5, which are essential to maintain tight junctions in HBMECs. In addition, LPS significantly increased the reactive oxygen species (ROS) productions. All effects induced by LPS in HBVMCs were reversed by adenoviral overexpression of superoxide dismutase, inhibition of NAD(P)H oxidase by apocynin or gain-function of AMPK by adenoviral overexpression of constitutively active mutant (AMPK-CA) or by 5-amino-4-imidazole carboxamide riboside (AICAR). Finally, the upregulation of AMPK by either AMPK-CA or AICAR abolished the levels of LPS-enhanced NAD(P)H oxidase subunit protein expressions. We conclude that AMPK activation improves the integrity of the BBB disrupted by LPS through suppressing the induction of NAD(P)H oxidase-derived ROS in HBMECs.
authors.affiliation: Department of Neurology, The First Affiliated Hospital (People's Hospital of Hunan Province), Hunan Normal University, Changsha, Hunan, China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Changsha Central Hospital, Changsha, Hunan, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Neurology, The First Affiliated Hospital (People's Hospital of Hunan Province), Hunan Normal University, Changsha, Hunan, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Neurology, The First Affiliated Hospital (People's Hospital of Hunan Province), Hunan Normal University, Changsha, Hunan, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Liang
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital (People's Hospital of Hunan Province), Hunan Normal University, Changsha, Hunan, China. Electronic address: liuzhan2004@126.com.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Liu
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000201:enzymology / Q000473:pathology*; D015153:Blotting, Western; D002199:Capillary Permeability / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology / Q000473:pathology*; D004789:Enzyme Activation / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D008070:Lipopolysaccharides / Q000633:toxicity*; D019255:NADPH Oxidases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018805:Sepsis / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology
chemical_list: D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; D019255:NADPH Oxidases; D055372:AMP-Activated Protein Kinases
keywords: AMPK; Aging; BBB; LPS; NAD(P)H oxidase; ROS