Schoneveld A H, Oude Nijhuis M M, van Middelaar B, Laman J D, de Kleijn D P V, Pasterkamp G
Department of Cardiology, Experimental Cardiology Laboratory, UMC, Heidelberglaan 100, Room G02.523, 3584 CX Utrecht, The Netherlands.
Cardiovasc Res. 2005 Apr 1;66(1):162-9. doi: 10.1016/j.cardiores.2004.12.016. Epub 2005 Jan 13.
Toll like receptors (Tlr) are essential in activation of the innate immune system. We recently described that peptidoglycan, an exogenous Tlr2 specific ligand, is present in human atherosclerotic plaques and associated with histological markers for plaque vulnerability. Also, endogenous Tlr2 ligands can be expressed in atherosclerotic tissues. Here, we determined whether Tlr2 stimulation promotes pro-inflammatory cytokine/chemokine production in vitro and augments neointima formation and development of atherosclerotic plaques in vivo.
We detected Tlr2 using Western blot and RT-PCR in human coronary arteries and primary adventitial fibroblasts. RNAse protection assay demonstrated significant induction of IL-1, IL-6, IL-8 and MCP-1 mRNA after Tlr2 stimulation in human adventitial fibroblasts in vitro. ELISA demonstrated induction of IL-6, IL-8 and MCP-1. In vivo application of Pam(3)Cys-SK(4), a synthetic Tlr2 ligand, on femoral arteries of C57BL/6 wild type (WT) mice using a peri-adventitial cuff, significantly enhanced neointima formation compared to control arteries. This increased inflammatory response was not observed in Tlr2 knockout (Tlr2-/-) mice. In ApoE knockout mice (ApoE-/-), application of the same Tlr2 ligand led to a significant increase in atherosclerotic plaque development.
Local arterial Tlr2 stimulation induced neointima and atherosclerotic plaque formation in mouse femoral arteries. Tlr2 stimulation may be an important mediator in arterial occlusive disease.
Toll样受体（Tlr）在激活天然免疫系统中至关重要。我们最近报道，肽聚糖作为一种外源性Tlr2特异性配体，存在于人类动脉粥样硬化斑块中，并与斑块易损性的组织学标志物相关。此外，内源性Tlr2配体也可在动脉粥样硬化组织中表达。在此，我们确定Tlr2刺激是否能在体外促进促炎细胞因子/趋化因子的产生，并在体内增强新生内膜形成和动脉粥样硬化斑块的发展。
我们使用蛋白质印迹法和逆转录-聚合酶链反应（RT-PCR）在人冠状动脉和原代外膜成纤维细胞中检测Tlr2。核糖核酸酶保护试验表明，体外Tlr2刺激后人外膜成纤维细胞中白细胞介素-1（IL-1）、白细胞介素-6（IL-6）、白细胞介素-8（IL-8）和单核细胞趋化蛋白-1（MCP-1）的信使核糖核酸（mRNA）有显著诱导。酶联免疫吸附测定（ELISA）显示IL-6、IL-8和MCP-1有诱导作用。使用外膜袖带将合成的Tlr2配体Pam(3)Cys-SK(4)体内应用于C57BL/6野生型（WT）小鼠的股动脉，与对照动脉相比，显著增强了新生内膜形成。在Tlr2基因敲除（Tlr2-/-）小鼠中未观察到这种炎症反应增强。在载脂蛋白E基因敲除小鼠（ApoE-/-）中，应用相同的Tlr2配体导致动脉粥样硬化斑块发展显著增加。
局部动脉Tlr2刺激诱导小鼠股动脉新生内膜和动脉粥样硬化斑块形成。Tlr2刺激可能是动脉闭塞性疾病的重要介质。
