Local overexpression of toll-like receptors at the vessel wall induces atherosclerotic lesion formation: synergism of TLR2 and TLR4.
OBJECTIVE
Atherosclerosis is now considered as a chronic inflammatory disease, and inflammation is closely related to immune systems, which consist of innate-immunity and adaptive-immunity. Recently, toll-like receptors (TLRs) have been identified as key components of innate-immunity. We examined the role of local expressions of TLRs at the vessel wall in atherosclerosis.


RESULTS
We transfected cDNA encoding human TLR2 and TLR4 into the carotid arterial vessel wall of rabbits fed high-cholesterol diets with the use of HVJ-liposome. The rabbits were transfected with (1) pCMV-beta-gal, (2) empty vector, (3) TLR2, (4) TLR4, (5) TLR2+4. X-gal staining and immunohistochemical analysis showed that the transfected plasmids were mainly expressed in the media. Neither TLR2 nor TLR4 transfection induced significant augmentation of atherosclerosis. Transfection of TLR2- and TLR4-containing HVJ synergistically accelerated atherosclerosis and increased expressions of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and MCP-1. Moreover, transfection of TLR2 and TLR4 resulted in synergistic activation of NF-kappaB at the vessel wall in vivo, and in vascular smooth muscle cells in vitro.


CONCLUSIONS
Expressions of both TLR2 and TLR4 at the vessel wall synergistically accelerated atherosclerosis. The present study revealed the role of TLRs expressed locally at the vessel wall in the early stage of atherosclerosis.
Shinohara
Masakazu
M
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan.
Hirata
Ken-ichi
K
Yamashita
Tomoya
T
Takaya
Tomofumi
T
Sasaki
Naoto
N
Shiraki
Rio
R
Ueyama
Tomomi
T
Emoto
Noriaki
N
Inoue
Nobutaka
N
Yokoyama
Mitsuhiro
M
Kawashima
Seinosuke
S
D000818:Animals; D030801:Animals, Genetically Modified; D002339:Carotid Arteries / Q000276:immunology* / Q000503:physiopathology; D002340:Carotid Artery Diseases / Q000276:immunology* / Q000503:physiopathology; D004036:Diet, Atherogenic; D004195:Disease Models, Animal; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D011817:Rabbits; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4