Effect of peroxisome proliferator-activated receptor-gamma ligands on the expression of retinoic acid-inducible gene-I in endothelial cells stimulated with lipopolysaccharide.
Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH box protein family and designated as a putative RNA helicase. RIG-I is implicated in host defense and inflammatory reactions by regulating the expression of various genes. RIG-I is expressed in endothelial cells and upregulated with lipopolysaccharide (LPS). Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a nuclear hormone receptor and regulates gene expressions in response to its specific ligands. In the present study, we examined the effect of PPAR-gamma ligands on the LPS-induced RIG-I expression in cultured human umbilical vein endothelial cells (HUVEC). 15-Deoxy-Delta(12,14)-prostaglandin J2 (15d-PGJ2), a metabolite of PGD2, is a natural ligand for PPAR-gamma and known to modulate inflammatory reactions by regulating the expression of various genes in PPAR-gamma-dependent and -independent manners. LPS-induced RIG-I expression in HUVEC was inhibited by pretreatment of the cells with 15d-PGJ2 in time-and concentration-dependent manners. However, ciglitazone and bisphenol A diglycide ether, authentic and specific ligands for PPAR-gamma, did not affect the RIG-I expression. These results suggest that 15d-PGJ2 inhibits LPS-induced RIG-I expression through a mechanism independent on PPAR-gamma. 15d-PGJ2 may regulate inflammatory reactions, at least in part, by inhibiting the expression of RIG-I.
Imaizumi
Tadaatsu
T
Department of Vascular Biology, Institute of Brain Science, Hirosaki University School of Medicine, Hirosaki 036-8562, Japan. timaizum@cc.hirosaki-u.ac.jp
Yamashita
Koji
K
Taima
Kageaki
K
Ishikawa
Akira
A
Yoshida
Hidemi
H
Satoh
Kei
K
D001483:Base Sequence; D002478:Cells, Cultured; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D047495:PPAR gamma / Q000378:metabolism*; D020365:RNA Helicases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D011971:Receptors, Immunologic; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D047495:PPAR gamma; D012333:RNA, Messenger; D011971:Receptors, Immunologic; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases