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.
Department of Internal Medicine III, Kurume University School of Medicine, Kurume 830 0011, Japan. shoichi@med.kurume-u.ac.jp
Sho-Ichi
S
Yamagishi
Yosuke
Y
Inagaki
Kazuo
K
Nakamura
Riichiro
R
Abe
Tadamichi
T
Shimizu
Akihiko
A
Yoshimura
Tsutomu
T
Imaizumi
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