title: NAD(P)H oxidase-mediated reactive oxygen species production alters astrocyte membrane molecular order via phospholipase A2.
abstract: ROS (reactive oxygen species) overproduction is an important underlying factor for the activation of astrocytes in various neuropathological conditions. In the present study, we examined ROS production in astrocytes and downstream effects leading to changes in the signalling cascade, morphology and membrane dynamics using menadione, a redox-active compound capable of inducing intracellular ROS. NAD(P)H oxidase-mediated menadione-induced ROS production, which then stimulated phosphorylation of p38 MAPK (mitogen-activated protein kinase) and ERK1/2 (extracellular-signal-regulated kinase 1/2), and increased actin polymerization and cytoskeletal protrusions. We also showed that astrocyte plasma membranes became more molecularly ordered under oxidative stress, which was abrogated by down-regulating cPLA2 (cytosolic phospholipase A2) either with a pharmacological inhibitor or by RNA interference. In addition, mild disruption of F-actin with cytochalasin D suppressed menadione-enhanced phosphorylation of cPLA2 and membrane alterations. Taken together, these results suggest an important role for ROS derived from NAD(P)H oxidase in activation of astrocytes to elicit biochemical, morphological and biophysical changes reminiscent of reactive astrocytes in pathological conditions.
authors.affiliation: Department of Biological Engineering, University of Missouri, Columbia, MO 65211, USA. donghui_zhu@urmc.rochester.edu
authors.forename: Donghui
authors.initials: D
authors.lastname: Zhu
authors.forename: Chunhua
authors.initials: C
authors.lastname: Hu
authors.forename: Wenwen
authors.initials: W
authors.lastname: Sheng
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Tan
authors.forename: Mark A
authors.initials: MA
authors.lastname: Haidekker
authors.forename: Albert Y
authors.initials: AY
authors.lastname: Sun
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Sun
authors.forename: James C-M
authors.initials: JC
authors.lastname: Lee
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000201:enzymology* / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology* / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D018613:Microscopy, Confocal; D019255:NADPH Oxidases / Q000378:metabolism*; D054467:Phospholipases A2 / Q000378:metabolism*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D024483:Vitamin K 3 / Q000494:pharmacology
chemical_list: D017382:Reactive Oxygen Species; D024483:Vitamin K 3; D019255:NADPH Oxidases; D054467:Phospholipases A2