Khreiss Tarek, József Levente, Potempa Lawrence A, Filep János G
Research Center, Maisonneuve-Rosemont Hospital and Department of Medicine , University of Montreal, Montreal, QC, Canada.
Circulation. 2004 Apr 27;109(16):2016-22. doi: 10.1161/01.CIR.0000125527.41598.68. Epub 2004 Mar 29.
C-reactive protein (CRP) has been suggested to actively amplify the inflammatory response underlying coronary heart diseases by directly activating endothelial cells. In this study, we investigated whether loss of the cyclic pentameric structure of CRP, resulting in formation of modified or monomeric CRP (mCRP), is a prerequisite for endothelial cell activation.
We examined the impact of native CRP and mCRP on the production of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8), key regulators of leukocyte recruitment, and on the expression of intercellular adhesion molecule-1 (ICAM-1), E-selectin, and vascular adhesion molecule-1 (VCAM-1) in human cultured coronary artery endothelial cells (HCAECs). Incubation with mCRP for 4 hours increased MCP-1 and IL-8 secretion and mRNA levels and expression of ICAM-1, E-selectin, and VCAM-1 protein and mRNA. Significant induction occurred at 1 to 5 microg/mL, reached a maximum at 30 microg/mL, and did not require the presence of serum. Native CRP was without detectable effects at 4 hours, whereas it enhanced cytokine release after a 24-hour incubation. An anti-FcgammaRIII (CD16) but not an anti-FcgammaRII (CD32) antibody produced a 14% to 32% reduction of the mCRP effects (P<0.05). mCRP but not CRP evoked phosphorylation of p38 mitogen-activated protein kinase, and inhibition of this kinase with SB 203580 reversed the effects of mCRP. Furthermore, culture of HCAECs in the presence of SB203580 markedly decreased mCRP-stimulated E-selectin and ICAM-1-dependent adhesion of neutrophils to HCAECs (P<0.001).
Loss of pentameric symmetry in CRP, resulting in formation of mCRP, promotes a proinflammatory HCAEC phenotype through a p38 MAPK-dependent mechanism.
有人提出C反应蛋白（CRP）可通过直接激活内皮细胞来积极放大冠心病潜在的炎症反应。在本研究中，我们调查了CRP环状五聚体结构的丧失，导致形成修饰型或单体型CRP（mCRP），是否是内皮细胞激活的先决条件。
我们检测了天然CRP和mCRP对单核细胞趋化蛋白-1（MCP-1）和白细胞介素-8（IL-8）的产生的影响，这两种蛋白是白细胞募集的关键调节因子，还检测了它们对人培养的冠状动脉内皮细胞（HCAECs）中细胞间黏附分子-1（ICAM-1）、E-选择素和血管细胞黏附分子-1（VCAM-1）表达的影响。用mCRP孵育4小时可增加MCP-1和IL-8的分泌以及mRNA水平，同时增加ICAM-1、E-选择素和VCAM-1蛋白及mRNA的表达。在1至5μg/mL时出现显著诱导，在30μg/mL时达到最大值，且不需要血清存在。天然CRP在4小时时无明显作用，而在孵育24小时后可增强细胞因子释放。抗FcγRIII（CD16）抗体而非抗FcγRII（CD32）抗体可使mCRP的作用降低14%至32%（P<0.05）。mCRP而非CRP可引起p38丝裂原活化蛋白激酶的磷酸化，用SB 203580抑制该激酶可逆转mCRP的作用。此外，在SB203580存在的情况下培养HCAECs可显著降低mCRP刺激的E-选择素和ICAM-1依赖的中性粒细胞与HCAECs黏附（P<0.001）。
CRP中五聚体对称性的丧失，导致mCRP的形成，通过p38丝裂原活化蛋白激酶依赖的机制促进促炎性HCAEC表型。
