title: Fluid shear stress attenuates hydrogen peroxide-induced c-Jun NH2-terminal kinase activation via a glutathione reductase-mediated mechanism.
abstract: c-Jun NH2-terminal kinase (JNK) is activated by a number of cellular stimuli including reactive oxygen species (ROS). Previous studies have demonstrated that fluid shear stress (flow) inhibits cytokine-induced JNK activation in endothelial cells (ECs). In the present study, we show JNK activation by ROS in ECs and hypothesized that flow inhibits ROS-induced JNK activation in ECs via modulation of cellular protection systems against ROS. JNK was activated by 300 micro mol/L hydrogen peroxide (H2O2) in bovine lung microvascular ECs (BLMVECs) with a peak at 60 minutes after stimulation (6.3+/-1.2-fold increase). Preexposure of BLMVECs to physiological steady laminar flow (shear stress=12 dyne/cm2) for 10 minutes significantly decreased H2O2-induced JNK activation. Thioredoxin and glutathione are cellular antioxidants that protect cells against ROS. Flow induced a significant increase in the ratio of reduced glutathione to oxidized glutathione consistent with a 1.6-fold increase in glutathione reductase (GR) activity. Preincubation of BLMVECs with the GR inhibitor, 1,3 bis-(2 chloroethyl)-1-nitrosourea, abolished the inhibitory effect of flow. In contrast, preincubation of BLMVECs with azelaic acid, a specific inhibitor for thioredoxin reductase, did not alter the effect of flow on H2O2-induced JNK activation. Overexpression of GR mimicked the effect of flow to inhibit JNK activation. These results suggest that flow activates GR, an important regulator of the intracellular redox state of glutathione, and exerts a protective mechanism against oxidative stress in endothelial cells.
authors.affiliation: Center for Cardiovascular Research, Cardiology Unit, Department of Medicine, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Hojo
authors.forename: Yuji
authors.initials: Y
authors.lastname: Saito
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Tanimoto
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Hoefen
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Baines
authors.forename: Kei
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Judith
authors.initials: J
authors.lastname: Haendeler
authors.forename: Reto
authors.initials: R
authors.lastname: Asmis
authors.forename: Bradford C
authors.initials: BC
authors.lastname: Berk
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D004789:Enzyme Activation; D005978:Glutathione / Q000502:physiology; D005980:Glutathione Reductase / Q000235:genetics / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors*; D048031:JNK Mitogen-Activated Protein Kinases; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008956:Models, Chemical; D016877:Oxidants / Q000037:antagonists & inhibitors*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D015398:Signal Transduction; D013314:Stress, Mechanical; D013879:Thioredoxins / Q000378:metabolism; D014162:Transfection
chemical_list: D016877:Oxidants; D013879:Thioredoxins; D006861:Hydrogen Peroxide; D005980:Glutathione Reductase; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D005978:Glutathione