Nijhuis Manon M Oude, Pasterkamp Gerard, Sluis Nienke I, de Kleijn Dominique P V, Laman Jon D, Ulfman Laurien H
Experimental Cardiology Laboratory, University Medical Center Utrecht, Utrecht, The Netherlands.
J Vasc Res. 2007;44(3):214-22. doi: 10.1159/000100420. Epub 2007 Feb 28.
The Toll-like receptor (TLR) 2/nucleotide-binding oligomerization domain ligand peptidoglycan (PG) has been shown to be present in macrophage-rich regions within atherosclerotic lesions, and stimulation of TLR2 promotes atherosclerotic plaque and intima formation in in vivo mouse models. We determined the effect of a PG preparation and Pam(3)Cys-SK(4), a synthetic TLR2 activator, on (1) adhesion molecule expression by flow cytometry; (2) monocyte adhesion under flow conditions, and (3) monocyte migration. The total adhesion (rolling and firm adhesion) of the PG-preparation-stimulated monocytes to L cells, constitutively expressing ICAM-1 (intercellular adhesion molecule-1) and E-selectin, was decreased. This was most likely due to the L-selectin shedding, since monocyte incubation with a blocking L-selectin antibody resulted in a comparable number of adherent monocytes as PG-stimulated cells. The PG preparation induced an increased percentage of firmly adherent, polarized cells and a beta(2)-integrin-dependent binding to ICAM-1-coated beads. Interestingly, the PG preparation induced a priming of the monocytes for increased migration towards the chemoattractant C5a which was TLR2 and beta(2)-integrin dependent. Pam(3)Cys-SK(4) gave comparable results to the PG preparation in all assays tested. This study demonstrates that PG activation of monocytes results in an increase in adhesive and migratory capacities of these cells. This might be a mechanism by which PG promotes atherosclerotic disease in vivo.
Toll样受体（TLR）2/核苷酸结合寡聚化结构域配体肽聚糖（PG）已被证明存在于动脉粥样硬化病变中富含巨噬细胞的区域，并且在体内小鼠模型中，刺激TLR2可促进动脉粥样硬化斑块和内膜形成。我们测定了PG制剂和合成TLR2激活剂Pam(3)Cys-SK(4)对以下方面的影响：（1）通过流式细胞术检测黏附分子表达；（2）流动条件下单核细胞黏附；（3）单核细胞迁移。PG制剂刺激的单核细胞与组成性表达细胞间黏附分子-1（ICAM-1）和E-选择素的L细胞的总黏附（滚动黏附和牢固黏附）减少。这很可能是由于L-选择素脱落，因为单核细胞与抗L-选择素阻断抗体孵育后，黏附的单核细胞数量与PG刺激的细胞相当。PG制剂诱导牢固黏附的极化细胞百分比增加，并诱导与ICAM-1包被微珠的β2整合素依赖性结合。有趣的是，PG制剂诱导单核细胞引发，使其向趋化因子C5a的迁移增加，这是TLR2和β2整合素依赖性的。在所有测试的实验中，Pam(3)Cys-SK(4)给出了与PG制剂类似的结果。这项研究表明，PG激活单核细胞会导致这些细胞的黏附能力和迁移能力增加。这可能是PG在体内促进动脉粥样硬化疾病的一种机制。
