CD36 signaling inhibits the translation of heat shock protein 70 induced by oxidized low density lipoprotein through activation of peroxisome proliferators-activated receptor gamma.
10.3858/emm.2008.40.6.658
- Author:
Kyoung Jin LEE
1
;
Eun Soo HA
;
Min Kyoung KIM
;
Sang Hoon LEE
;
Jae Sung SUH
;
Sun Hee LEE
;
Kyeong Han PARK
;
Jeong Hyun PARK
;
Dae Joong KIM
;
Dongmin KANG
;
Byung Chul KIM
;
Dooil JEOUNG
;
Young Kyoun KIM
;
Ho Dirk KIM
;
Jang Hee HAHN
Author Information
1. Department of Anatomy and Cell Biology, College of Medicine, Kangwon National University, Chunchon, Korea. jhahn@kangwon.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
antigens, CD36;
HSP70 heat-shock proteins;
oxidized low density lipoprotein;
PPAR gamma;
protein biosynthesis
- MeSH:
Antigens, CD36/*physiology;
Cell Line, Tumor;
Chromans/pharmacology;
Cycloheximide/pharmacology;
HSP70 Heat-Shock Proteins/*biosynthesis;
Humans;
Lipoproteins, LDL/pharmacology/*physiology;
Monocytes/drug effects/metabolism;
PPAR gamma/agonists/antagonists & inhibitors/*physiology;
Protein Synthesis Inhibitors/pharmacology;
Signal Transduction;
Thiazolidinediones/pharmacology
- From:Experimental & Molecular Medicine
2008;40(6):658-668
- CountryRepublic of Korea
- Language:English
-
Abstract:
Oxidized LDL (OxLDL), a causal factor in atherosclerosis, induces the expression of heat shock proteins (Hsp) in a variety of cells. In this study, we investigated the role of CD36, an OxLDL receptor, and peroxisome proliferator-activated receptor gamma (PPAR gamma) in OxLDL-induced Hsp70 expression. Overexpression of dominant-negative forms of CD36 or knockdown of CD36 by siRNA transfection increased OxLDL-induced Hsp70 protein expression in human monocytic U937 cells, suggesting that CD36 signaling inhibits Hsp70 expression. Similar results were obtained by the inhibition of PPAR gamma activity or knockdown of PPAR gamma expression. In contrast, overexpression of CD36, which is induced by treatment of MCF-7 cells with troglitazone, decreased Hsp70 protein expression induced by OxLDL. Interestingly, activation of PPAR gamma through a synthetic ligand, ciglitazone or troglitazone, decreased the expression levels of Hsp70 protein in OxLDL-treated U937 cells. However, major changes in Hsp70 mRNA levels were not observed. Cycloheximide studies demonstrate that troglitazone attenuates Hsp70 translation but not Hsp70 protein stability. PPAR gamma siRNA transfection reversed the inhibitory effects of troglitazone on Hsp70 translation. These results suggest that CD36 signaling may inhibit stress- induced gene expression by suppressing translation via activation of PPAR gamma in monocytes. These findings reveal a new molecular basis for the anti-inflammatory effects of PPAR gamma.
