Pigment epithelium-derived factor inhibits TNF-alpha-induced interleukin-6 expression in endothelial cells by suppressing NADPH oxidase-mediated reactive oxygen species generation.
Pigment epithelium-derived factor (PEDF) has recently been shown to be involved in the pathogenesis of proliferative diabetic retinopathy. Atherosclerosis is an inflammatory-fibroproliferative disease as well. Oxidative stress plays a major role in retinopathy and atherosclerosis. Accordingly, we investigated effects of PEDF on reactive oxygen species (ROS) generation, NF-kappaB activation and interleukin (IL)-6 expression in TNF-alpha-exposed HUVEC. TNF-alpha significantly increased intracellular ROS generation, which was completely blocked by PEDF or diphenylene iodonium, an inhibitor of NADPH oxidase. Further, PEDF completely prevented the TNF-alpha-induced increase in NADPH oxidase activity. PEDF or an antioxidant, N-acetylcysteine, significantly inhibited the TNF-alpha-induced NF-kappaB activation. PEDF inhibited TNF-alpha-induced expression of IL-6 at both mRNA and protein levels. Moreover, TNF-alpha downregulated PEDF mRNA levels. Ligand blot analysis revealed that HUVEC possessed a membrane protein with binding affinity for PEDF. The results demonstrated that PEDF inhibited TNF-alpha-induced NF-kappaB activation and subsequent IL-6 overexpression in HUVEC by suppressing NADPH oxidase-mediated ROS generation. Our present study suggests that PEDF may play an important role in the development and progression of atherosclerosis.
Yamagishi
Sho-Ichi
S
Department of Internal Medicine III, Kurume University School of Medicine, Kurume 830 0011, Japan. shoichi@med.kurume-u.ac.jp
Inagaki
Yosuke
Y
Nakamura
Kazuo
K
Abe
Riichiro
R
Shimizu
Tadamichi
T
Yoshimura
Akihiko
A
Imaizumi
Tsutomu
T
D002478:Cells, Cultured; D042783:Endothelial Cells / Q000737:chemistry / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005136:Eye Proteins / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D019255:NADPH Oxidases / Q000032:analysis / Q000378:metabolism*; D016328:NF-kappa B / Q000032:analysis / Q000378:metabolism; D009414:Nerve Growth Factors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism*; D015843:Serpins / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
D005136:Eye Proteins; D015850:Interleukin-6; D019255:NADPH Oxidases; D016328:NF-kappa B; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D015843:Serpins; D014409:Tumor Necrosis Factor-alpha; D020830:rac1 GTP-Binding Protein; D000099174:Pigment Epithelium-Derived Factor