1. Rap1 GTPase Inhibits Tumor Necrosis Factor-α-Induced Choroidal Endothelial Migration via NADPH Oxidase- and NF-κB-Dependent Activation of Rac1.
- Author
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Wang H, Fotheringham L, Wittchen ES, and Hartnett ME
- Subjects
- Animals, Cell Movement physiology, Cells, Cultured, Choroid metabolism, Choroidal Neovascularization genetics, Choroidal Neovascularization pathology, Endothelial Cells physiology, Enzyme Activation physiology, Female, Mice, Inbred C57BL, Neuropeptides physiology, Reactive Oxygen Species metabolism, Signal Transduction physiology, Tumor Necrosis Factor-alpha biosynthesis, Tumor Necrosis Factor-alpha genetics, Up-Regulation physiology, rac1 GTP-Binding Protein physiology, Choroidal Neovascularization metabolism, NADPH Oxidases physiology, NF-kappa B physiology, Neuropeptides metabolism, Tumor Necrosis Factor-alpha physiology, rac1 GTP-Binding Protein metabolism
- Abstract
Macrophage-derived tumor necrosis factor (TNF)-α has been found in choroidal neovascularization (CNV) surgically removed from patients with age-related macular degeneration. However, the role of TNF-α in CNV development remains unclear. In a murine laser-induced CNV model, compared with un-lasered controls, TNF-α mRNA was increased in retinal pigment epithelial and choroidal tissue, and TNF-α colocalized with lectin-stained migrating choroidal endothelial cells (CECs). Inhibition of TNF-α with a neutralizing antibody reduced CNV volume and reactive oxygen species (ROS) level around CNV. In CECs, pretreatment with the antioxidant apocynin or knockdown of p22phox, a subunit of NADPH oxidase, inhibited TNF-α-induced ROS generation. Apocynin reduced TNF-α-induced NF-κB and Rac1 activation, and inhibited TNF-α-induced CEC migration. TNF-α-induced Rac1 activation and CEC migration were inhibited by NF-κB inhibitor Bay11-7082. Overexpression of Rap1a prevented TNF-α-induced ROS generation and reduced NF-κB and Rac1 activation. Activation of Rap1 by 8-(4-chlorophenylthio)adenosine-2'-O-Me-cAMP prevented TNF-α-induced CEC migration and reduced laser-induced CNV volume, ROS generation, and activation of NF-κB and Rac1. These findings provide evidence that active Rap1a inhibits TNF-α-induced CEC migration by inhibiting NADPH oxidase-dependent NF-κB and Rac1 activation and suggests that Rap1a de-escalates CNV development by interfering with ROS-dependent signaling in several steps of the pathogenic process., (Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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