From the University of Freiburg Medical Center, Department of Plastic and Hand Surgery (J.R.T., D.B., Y.S., K.G., V.M., H.B., G.B.S., S.U.E.) and Section of Endocrine Surgery, Clinic of General, Visceral and Thoracic Surgery, Academic Teaching Hospital University of Hamburg (E.v.D.), Reinbeck, Germany; Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (J.H., A.S., K.P.); Imperial College London, Department of Medicine, London, United Kingdom (K.J.W.); and CVPath Institute, Gaithersburg, MD (F.K., R.V.).
Circulation. 2014 Jul 1;130(1):35-50. doi: 10.1161/CIRCULATIONAHA.113.007124. Epub 2014 Apr 28.
The relevance of the dissociation of circulating pentameric C-reactive protein (pCRP) to its monomeric subunits (mCRP) is poorly understood. We investigated the role of conformational C-reactive protein changes in vivo.
We identified mCRP in inflamed human striated muscle, human atherosclerotic plaque, and infarcted myocardium (rat and human) and its colocalization with inflammatory cells, which suggests a general causal role of mCRP in inflammation. This was confirmed in rat intravital microscopy of lipopolysaccharide-induced cremasteric muscle inflammation. Intravenous pCRP administration significantly enhanced leukocyte rolling, adhesion, and transmigration via localized dissociation to mCRP in inflamed but not noninflamed cremaster muscle. This was confirmed in a rat model of myocardial infarction. Mechanistically, this process was dependent on exposure of lysophosphatidylcholine on activated cell membranes, which is generated after phospholipase A2 activation. These membrane changes could be visualized intravitally on endothelial cells, as could the colocalized mCRP generation. Blocking of phospholipase A2 abrogated C-reactive protein dissociation and thereby blunted the proinflammatory effects of C-reactive protein. Identifying the dissociation process as a therapeutic target, we stabilized pCRP using 1,6-bis(phosphocholine)-hexane, which prevented dissociation in vitro and in vivo and consequently inhibited the generation and proinflammatory activity of mCRP; notably, it also inhibited mCRP deposition and inflammation in rat myocardial infarction.
These results provide in vivo evidence for a novel mechanism that localizes and aggravates inflammation via phospholipase A2-dependent dissociation of circulating pCRP to mCRP. mCRP is proposed as a pathogenic factor in atherosclerosis and myocardial infarction. Most importantly, the inhibition of pCRP dissociation represents a promising, novel anti-inflammatory therapeutic strategy.
循环五聚体 C 反应蛋白（pCRP）与其单体亚基（mCRP）分离的相关性尚不清楚。我们研究了体内构象 C 反应蛋白变化的作用。
我们在人类横纹肌、人动脉粥样硬化斑块和梗死心肌（大鼠和人类）中鉴定出 mCRP，以及其与炎症细胞的共定位，这表明 mCRP 在炎症中具有普遍的因果作用。这在大鼠脂多糖诱导的提睾肌炎症的活体显微镜检查中得到了证实。静脉内给予 pCRP 可显著增强白细胞滚动、粘附和迁移，这是通过在炎症而不是非炎症的提睾肌中局部分离为 mCRP 实现的。这在大鼠心肌梗死模型中得到了证实。从机制上讲，这个过程依赖于激活细胞膜上溶血磷脂酰胆碱的暴露，而这是在磷脂酶 A2 激活后产生的。这些膜变化可以在血管内皮细胞上进行活体可视化，也可以可视化共定位的 mCRP 生成。阻断磷脂酶 A2 可阻断 C 反应蛋白的解离，从而减弱 C 反应蛋白的促炎作用。将解离过程确定为治疗靶点，我们使用 1,6-双（磷酸胆碱）-己烷稳定 pCRP，这可防止体外和体内的解离，并因此抑制 mCRP 的生成和促炎活性；值得注意的是，它还抑制了大鼠心肌梗死中的 mCRP 沉积和炎症。
这些结果提供了体内证据，证明了一种通过循环 pCRP 与 mCRP 的磷脂酶 A2 依赖性解离来局部加重炎症的新机制。mCRP 被提议作为动脉粥样硬化和心肌梗死的致病因素。最重要的是，抑制 pCRP 解离代表了一种有前途的新型抗炎治疗策略。
