This work establishes that Kupffer cell release of platelet activating factor (PAF), a lipidic molecule with pro-inflammatory and vasoactive signaling properties, dictates dose-limiting siRNA nanocarrier-associated toxicities. High-dose intravenous injection of siRNA-polymer nano-polyplexes (si-NPs) elicited acute, shock-like symptoms in mice, associated with increased plasma PAF and consequently reduced PAF acetylhydrolase (PAF-AH) activity. These symptoms were completely prevented by prophylactic PAF receptor inhibition or Kupffer cell depletion. Assessment of varied si-NP chemistries confirmed that toxicity level correlated to relative uptake of the carrier by liver Kupffer cells and that this toxicity mechanism is dependent on carrier endosome disruptive function. 4T1 tumor-bearing mice, which exhibit increased circulating leukocytes, displayed greater sensitivity to these toxicities. PAF-mediated toxicities were generalizable to commercial delivery reagent in vivo-jetPEI® and an MC3 lipid formulation matched to an FDA-approved nanomedicine. These collective results establish Kupffer cell release of PAF as a key mediator of siRNA nanocarrier toxicity and identify PAFR inhibition as an effective strategy to increase siRNA nanocarrier tolerated dose.

这项工作确立了库普弗细胞释放血小板激活因子 (PAF)，一种具有促炎和血管活性信号特性的脂质分子，决定了与剂量限制性 siRNA 纳米载体相关的毒性。高剂量静脉注射 siRNA 聚合物纳米复合物 (si-NPs) 在小鼠中引起急性休克样症状，与血浆 PAF 增加相关，从而降低 PAF 乙酰水解酶 (PAF-AH) 活性。这些症状通过预防性 PAF 受体抑制或枯否细胞耗竭完全预防。对各种 si-NP 化学物质的评估证实，毒性水平与肝库普弗细胞对载体的相对摄取相关，并且这种毒性机制取决于载体内体破坏功能。4T1 荷瘤小鼠，循环白细胞增多，对这些毒性表现出更高的敏感性。PAF 介导的毒性可推广到商业递送试剂 in vivo-jetPEI® 和与 FDA 批准的纳米药物相匹配的 MC3 脂质制剂。这些集体结果确定 PAF 的库普弗细胞释放是 siRNA 纳米载体毒性的关键介质，并将 PAFR 抑制确定为增加 siRNA 纳米载体耐受剂量的有效策略。