Translational Research Laboratory, Advanced Centre for Treatment, Research and Education in Cancer, Tata Memorial Centre, Kharghar, Navi Mumbai, India.
PLoS One. 2020 Mar 4;15(3):e0229017. doi: 10.1371/journal.pone.0229017. eCollection 2020.
We have earlier reported that cell-free chromatin (cfCh) particles that are released from dying cells, or those that circulate blood, can readily enter into healthy cells, illegitimately integrate into their genomes and induce dsDNA breaks, apoptosis and intense activation of inflammatory cytokines. We hypothesized that sepsis is caused by cfCh released from dying host cells following microbial infection leading to bystander host cell apoptosis and inflammation which are perpetuated in a vicious cycle with release of more cfCh from dying host cells. To test this hypothesis we used three cfCh inactivating agents namely 1) anti-histone antibody complexed nanoparticles which inactivate cfCh by binding to histones; 2) DNase I which inactivates cfCh by degrading its DNA component, and 3) a novel pro-oxidant combination of Resveratrol and Copper which, like DNase I, inactivates cfCh by degrading its DNA component. Female C57 BL/6 mice, 6-8 weeks old, were administered a single i.p. injection of LPS at a dose of 10 mg/Kg or 20 mg/Kg with or without concurrent treatment with the above cfCh inactivating agents. Administration of cfCh inactivating agents concurrently with LPS resulted in prevention of following pathological parameters: 1) release of cfCh in extra-cellular spaces of brain, lung and heart and in circulation; 2) release of inflammatory cytokines in circulation; 3) activation of DNA damage, apoptosis and inflammation in cells of thymus, spleen and in PBMCs; 4) DNA damage, apoptosis and inflammation in cells of lung, liver, heart, brain, kidney and small intestine; 5) liver and kidney dysfunction and elevation of serum lactate; 6) coagulopathy, fibrinolysis and thrombocytopenia; 7) lethality. We conclude that cfCh that are released from dying host cells in response to bacterial endotoxin represents a global instigator of sepsis. cfCh inactivation may provide a novel approach to management of sepsis in humans.
我们之前曾报道过，来自死亡细胞或循环血液的无细胞染色质（cfCh）颗粒很容易进入健康细胞，非法整合到其基因组中，并诱导双链 DNA 断裂、细胞凋亡和强烈的炎症细胞因子激活。我们假设，败血症是由微生物感染后死亡的宿主细胞释放的 cfCh 引起的，导致旁观者宿主细胞凋亡和炎症，而这些又通过更多来自死亡宿主细胞的 cfCh 的释放而在恶性循环中持续存在。为了验证这一假设，我们使用了三种 cfCh 失活剂，即 1）与组蛋白结合的抗组蛋白抗体复合物纳米颗粒，通过与组蛋白结合来失活 cfCh；2）DNase I 通过降解其 DNA 成分来失活 cfCh；3）一种新型的白藜芦醇和铜的促氧化剂组合，与 DNase I 类似，通过降解其 DNA 成分来失活 cfCh。6-8 周龄的雌性 C57BL/6 小鼠接受单次腹腔注射 LPS，剂量为 10mg/Kg 或 20mg/Kg，并同时给予上述 cfCh 失活剂。cfCh 失活剂与 LPS 同时给药可预防以下病理参数：1）cfCh 在脑、肺和心脏的细胞外空间以及循环中的释放；2）循环中炎症细胞因子的释放；3）胸腺、脾脏和 PBMC 中 DNA 损伤、细胞凋亡和炎症的激活；4）肺、肝、心、脑、肾和小肠细胞中的 DNA 损伤、细胞凋亡和炎症；5）肝肾功能障碍和血清乳酸升高；6）凝血功能障碍、纤维蛋白溶解和血小板减少；7）致死性。我们得出结论，细菌内毒素作用下死亡的宿主细胞释放的 cfCh 是败血症的全身性引发因素。cfCh 失活可能为人类败血症的治疗提供一种新方法。
