Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada.
Cancer Research Institute, Queen's University, Kingston, Ontario, Canada.
J Thromb Haemost. 2016 Nov;14(11):2274-2286. doi: 10.1111/jth.13493.
Essentials Dysregulated DNA and histone release can promote pathological immunothrombosis. Weibel-Palade bodies (WPBs) are sentinel-like organelles that respond to proinflammatory stimuli. Histones induce WPB exocytosis in a caspase, calcium and charge-dependent mechanism. A targetable axis may exist between DNA/histones and WPBs in inflammation and immunothrombosis.
Background Damage-associated molecular patterns (DAMPs), including molecules such as DNA and histones, are released into the blood following cell death. DAMPs promote a procoagulant phenotype through enhancement of thrombin generation and platelet activation, thereby contributing to immunothrombosis. Weibel-Palade bodies (WPBs) are dynamic endothelial cell organelles that contain procoagulant and proinflammatory mediators, such as von Willebrand factor (VWF), and are released in response to cell stresses. VWF mediates platelet adhesion and aggregation, and has been implicated as a procoagulant component of the innate immune response. Objective To determine the influence of histones and DNA on WPB release, and characterize their association in models of inflammation. Methods We treated C57BL/6J mice and cultured endothelial cells with histones (unfractionated, lysine-rich or arginine-rich) and DNA, and measured WPB exocytosis. We used inhibitors to determine a mechanism of histone-induced WPB release in vitro. We characterized the release of DAMPs and WPBs in response to acute and chronic inflammation in human and murine models. Results and conclusions Histones, but not DNA, induced the release of VWF (1.46-fold) from WBPs and caused thrombocytopenia (0.74-fold), which impaired arterial thrombus formation in mice. Histones induced WPB release from endothelial cells in a caspase-dependent, calcium-dependent and charge-dependent manner, and promoted platelet capture in a flow chamber model of VWF-platelet string formation. The levels of DAMPs and WPB-released proteins were elevated during inflammation, and were positively correlated in chronic inflammation. These studies showed that DAMPs can regulate the function and level of VWF by inducing its release from endothelial WPBs. This DAMP-WPB axis may propagate immunothrombosis associated with inflammation.
DNA 和组蛋白的失调释放可促进病理性免疫血栓形成。Weibel-Palade 体（WPB）是对促炎刺激做出反应的类似哨兵的细胞器。组蛋白通过 caspase、钙和电荷依赖性机制诱导 WPB 胞吐。在炎症和免疫血栓形成中，可能存在一个针对 DNA/组蛋白和 WPB 的可靶向轴。
背景 损伤相关分子模式（DAMPs），包括 DNA 和组蛋白等分子，在细胞死亡后释放到血液中。DAMPs 通过增强凝血酶生成和血小板激活来促进促凝表型，从而导致免疫血栓形成。Weibel-Palade 体（WPB）是动态的内皮细胞细胞器，包含促凝和促炎介质，如血管性血友病因子（VWF），并在受到细胞应激时释放。VWF 介导血小板黏附和聚集，并被认为是先天免疫反应的促凝成分。目的 确定组蛋白和 DNA 对 WPB 释放的影响，并在炎症模型中描述它们的关联。方法 我们用组蛋白（未分级、富含赖氨酸或富含精氨酸）和 DNA 处理 C57BL/6J 小鼠和培养的内皮细胞，并测量 WPB 胞吐作用。我们使用抑制剂来确定组蛋白诱导 WPB 释放的机制。我们描述了在人类和小鼠模型中急性和慢性炎症对 DAMPs 和 WPB 释放的影响。结果和结论 组蛋白而非 DNA 诱导 WPB 释放 VWF（增加 1.46 倍）并导致血小板减少症（减少 0.74 倍），从而损害了小鼠的动脉血栓形成。组蛋白以 caspase 依赖性、钙依赖性和电荷依赖性方式诱导内皮细胞 WPB 释放，并在 VWF-血小板串形成的流动室模型中促进血小板捕获。在炎症过程中，DAMPs 和 WPB 释放蛋白的水平升高，在慢性炎症中呈正相关。这些研究表明，DAMPs 可以通过诱导其从内皮 WPB 释放来调节 VWF 的功能和水平。这个 DAMP-WPB 轴可能会传播与炎症相关的免疫血栓形成。
