Developments in mRNA/lipid nanoparticle (LNP) technology have advanced the fields of vaccinology and gene therapy, raising questions about immunogenicity. While some mRNA/LNPs generate an adjuvant-like environment in muscle tissue, other mRNA/LNPs are distinct in their capacity for multiple rounds of therapeutic delivery. We evaluate the adjuvancy of components of mRNA/LNPs by phenotyping cellular infiltrate at injection sites, tracking uptake by immune cells, and assessing the inflammatory state. Delivery of 9 common, but chemically distinct, LNPs to muscle revealed two classes of inflammatory gene expression programs: inflammatory (Class A) and noninflammatory (Class B). We find that intramuscular injection with Class A, but not Class B, empty LNPs (eLNPs) induce robust neutrophil infiltration into muscle within 2 h and a diverse myeloid population within 24 h. Single-cell RNA sequencing revealed SM-102-mediated expression of inflammatory chemokines by myeloid infiltrates within muscle 1 day after injection. Surprisingly, we found direct transfection of muscle infiltrating myeloid cells and splenocytes 24 h after intramuscular mRNA/LNP administration. Transfected myeloid cells within the muscle exhibit an activated phenotype 24 h after injection. Similarly, directly transfected splenic lymphocytes and dendritic cells (DCs) are differentially activated by Class A or Class B containing mRNA/LNP. Within the splenic DC compartment, type II conventional DCs (cDC2s) are directly transfected and activated by Class A mRNA/LNP. Together, we show that mRNA and LNPs work synergistically to provide the necessary innate immune stimuli required for effective vaccination. Importantly, this work provides a design framework for vaccines and therapeutics alike.

中文翻译：

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不同的炎症程序是肌内脂质纳米颗粒反应的基础


mRNA/脂质纳米颗粒 （LNP） 技术的发展推动了疫苗学和基因治疗领域的发展，引发了对免疫原性的问题。虽然一些 mRNA/LNP 在肌肉组织中产生类似佐剂的环境，但其他 mRNA/LNP 在多轮治疗递送的能力上是不同的。我们通过对注射部位的细胞浸润进行表型分析、跟踪免疫细胞的摄取和评估炎症状态来评估 mRNA/LNP 成分的佐剂。将 9 种常见但化学性质不同的 LNP 递送到肌肉揭示了两类炎症基因表达程序：炎症性（A 类）和非炎症性（B 类）。我们发现，用 A 类而不是 B 类空 LNP （eLNP） 肌肉注射在 2 小时内诱导强壮的中性粒细胞浸润到肌肉中，在 24 小时内诱导多样化的髓系群体。单细胞 RNA 测序显示注射后 1 天肌肉内髓系浸润介导的炎症趋化因子的 SM-102 介导表达。令人惊讶的是，我们发现肌肉注射 mRNA/LNP 给药后 24 小时肌肉浸润髓细胞和脾细胞的直接转染。注射后 24 小时，肌肉内转染的髓系细胞表现出活化的表型。同样，直接转染的脾淋巴细胞和树突状细胞 （DC） 被含有 mRNA/LNP 的 A 类或 B 类细胞差异激活。在脾 DC 区室内，II 型常规 DC （cDC2） 被 A 类 mRNA/LNP 直接转染和激活。我们共同表明，mRNA 和 LNP 协同作用，提供有效疫苗接种所需的必要先天免疫刺激。重要的是，这项工作为疫苗和治疗方法提供了一个设计框架。