Oroszlán Melinda, Herczenik Eszter, Rugonfalvi-Kiss Szabolcs, Roos Anja, Nauta Alma J, Daha Mohamed R, Gombos Imre, Karádi István, Romics László, Prohászka Zoltán, Füst George, Cervenak László
3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary.
Int Immunol. 2006 Jun;18(6):871-8. doi: 10.1093/intimm/dxl023. Epub 2006 Apr 24.
The role of C-reactive protein (CRP) in atherosclerosis is controversial. It is not clear, either, if the presumed endothelium-activating effect of CRP resides in native CRP (nCRP) or in a conformational isoform of CRP known as modified CRP (mCRP). In the present study we evaluated and compared the effect of nCRP, recombinant modified CRP (rmCRP) and urea-modified CRP (umCRP) on human umbilical vein endothelial cells (HUVECs). CRP preparations were carefully analyzed by biochemical, immunological and cell biological methods in order to avoid endotoxin or sodium azide contamination as well as inappropriate conformational changes, which together had possibly been the main reason for the previously published controversial results. Neither nCRP nor mCRP showed significant cytotoxicity up to 100 microg ml(-1) at 24 h but high concentrations of CRPs induced cell death at 48 h. rmCRP but not nCRP nor umCRP showed membrane binding to HUVEC by confocal microscopy. However, none of the CRP forms induced intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin expression or IL-8 production. Monocyte chemotactic protein-1 production was weakly inhibited by high concentration of both nCRP and rmCRP, analyzed by sandwich ELISA. Neither nCRP nor mCRP could induce pro-inflammatory changes in the phenotype of HUVECs. Therefore, our present findings do not support the notion that different isoforms of CRP alone have significant effects on inflammation of the vessel wall via an interaction with endothelial cells (ECs), although one cannot exclude the possibility that there may be significant differences among various types of ECs in the response to CRP.
C反应蛋白（CRP）在动脉粥样硬化中的作用存在争议。同样不清楚的是，CRP假定的内皮激活作用是存在于天然CRP（nCRP）中，还是存在于一种称为修饰CRP（mCRP）的CRP构象异构体中。在本研究中，我们评估并比较了nCRP、重组修饰CRP（rmCRP）和尿素修饰CRP（umCRP）对人脐静脉内皮细胞（HUVECs）的影响。通过生化、免疫和细胞生物学方法对CRP制剂进行了仔细分析，以避免内毒素或叠氮化钠污染以及不适当的构象变化，这些因素可能共同导致了先前发表的有争议结果的主要原因。在24小时时，nCRP和mCRP在浓度高达100μg/ml时均未显示出明显的细胞毒性，但高浓度的CRP在48小时时诱导细胞死亡。通过共聚焦显微镜观察，rmCRP而非nCRP和umCRP显示出与HUVECs的膜结合。然而，没有一种CRP形式能诱导细胞间黏附分子-1、血管细胞黏附分子-1、E-选择素表达或IL-8产生。通过夹心ELISA分析，高浓度的nCRP和rmCRP均微弱抑制单核细胞趋化蛋白-1的产生。nCRP和mCRP均不能诱导HUVECs表型发生促炎变化。因此，我们目前的研究结果不支持单独的不同CRP异构体通过与内皮细胞（ECs）相互作用对血管壁炎症有显著影响这一观点，尽管不能排除不同类型的ECs对CRP的反应可能存在显著差异的可能性。
