Center of Excellence in Infectious Disease, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA.
Proc Natl Acad Sci U S A. 2012 Dec 18;109(51):21052-7. doi: 10.1073/pnas.1216195109. Epub 2012 Dec 3.
Hypersecretion of cytokines by innate immune cells is thought to initiate multiple organ failure in murine models of sepsis. Whether human cytokine storm also plays a similar role is not clear. Here, we show that human hematopoietic cells are required to induce sepsis-induced mortality following cecal ligation and puncture (CLP) in the severely immunodeficient nonobese diabetic (NOD)/SCID/IL2Rγ(-/-) mice, and siRNA treatment to inhibit HMGB1 release by human macrophages and dendritic cells dramatically reduces sepsis-induced mortality. Following CLP, compared with immunocompetent WT mice, NOD/SCID/IL2Rγ(-/-) mice did not show high levels of serum HMGB1 or murine proinflammatory cytokines and were relatively resistant to sepsis-induced mortality. In contrast, NOD/SCID/IL2Rγ(-/-) mice transplanted with human hematopoietic stem cells [humanized bone marrow liver thymic mice (BLT) mice] showed high serum levels of HMGB1, as well as multiple human but not murine proinflammatory cytokines, and died uniformly, suggesting human cytokines are sufficient to induce organ failure in this model. Moreover, targeted delivery of HMGB1 siRNA to human macrophages and dendritic cells using a short acetylcholine receptor (AchR)-binding peptide [rabies virus glycoprotein (RVG)-9R] effectively suppressed secretion of HMGB1, reduced the human cytokine storm, human lymphocyte apoptosis, and rescued humanized mice from CLP-induced mortality. siRNA treatment was also effective when started after the appearance of sepsis symptoms. These results show that CLP in humanized mice provides a model to study human sepsis, HMGB1 siRNA might provide a treatment strategy for human sepsis, and RVG-9R provides a tool to deliver siRNA to human macrophages and dendritic cells that could potentially be used to suppress a variety of human inflammatory diseases.
先天免疫细胞的细胞因子过度分泌被认为是引发脓毒症小鼠模型多器官衰竭的原因。人类细胞因子风暴是否也起类似作用尚不清楚。在这里，我们显示，在严重免疫缺陷的非肥胖型糖尿病（NOD）/SCID/IL2Rγ（-/-）小鼠的盲肠结扎和穿孔（CLP）后，需要人造血细胞来诱导脓毒症诱导的死亡率，并且 siRNA 处理抑制人巨噬细胞和树突状细胞释放 HMGB1 可显著降低脓毒症诱导的死亡率。与免疫功能正常的 WT 小鼠相比，在 CLP 后，NOD/SCID/IL2Rγ（-/-）小鼠没有表现出高水平的血清 HMGB1 或鼠前炎性细胞因子，并且对脓毒症诱导的死亡率相对具有抗性。相比之下，用人类造血干细胞移植的 NOD/SCID/IL2Rγ（-/-）小鼠 [人源化骨髓肝胸腺小鼠（BLT）] 显示出高水平的血清 HMGB1 以及多种人类而非鼠类前炎性细胞因子，并且均匀死亡，表明人类细胞因子足以在该模型中诱导器官衰竭。此外，使用短乙酰胆碱受体（AchR）结合肽[狂犬病病毒糖蛋白（RVG）-9R]将 HMGB1 siRNA 靶向递送至人巨噬细胞和树突状细胞，可有效抑制 HMGB1 的分泌，减少人类细胞因子风暴，减少人淋巴细胞凋亡，并将人源化小鼠从 CLP 诱导的死亡率中挽救出来。在出现脓毒症症状后开始 siRNA 治疗也是有效的。这些结果表明，在人源化小鼠中的 CLP 提供了一种研究人类脓毒症的模型，HMGB1 siRNA 可能为人类脓毒症提供一种治疗策略，并且 RVG-9R 提供了一种将 siRNA 递送至人巨噬细胞和树突状细胞的工具，可能用于抑制多种人类炎症性疾病。
