Control over Imidazoquinoline Immune Stimulation by pH-Degradable Poly(norbornene) Nanogels
作者:Johannes Kockelmann、Judith Stickdorn、Sabah Kasmi、Jana De Vrieze、Michaela Pieszka、David Yuen W. Ng、Sunil A. David、Bruno G. De Geest、Lutz Nuhn
DOI:10.1021/acs.biomac.0c00205
日期:2020.6.8
The reactivation of the innate immune system by toll-like receptor (TLR) agonists holds promise for anticancer immunotherapy. Severe side effects caused by unspecific and systemic activation of the immune system upon intravenous injection prevent the use of small-molecule TLR agonists for such purposes. However, a covalent attachment of small-molecule imidazoquinoline (IMDQ) TLR7/8 agonists to pH-degradable polymeric nanogels could be shown to drastically reduce the systemic inflammation but retain the activity to tumoral tissues and their draining lymph nodes. Here, we introduce the synthesis of poly(norbornene)-based, acid-degradable nanogels for the covalent ligation of IMDQs. While the intact nanogels trigger sufficient TLR7/8 receptor stimulation, their degraded version of soluble, IMDQ-conjugated poly(norbornene) chains hardly activates TLR7/8. This renders their clinical safety profile, as degradation products are obtained, which would not only circumvent nanoparticle accumulation in the body but also provide nonactive, polymer-bound IMDQ species. Their immunologically silent behavior guarantees both spatial and temporal control over immune activity and, thus, holds promise for improved clinical applications.
通过 Toll 样受体(TLR)激动剂重新激活固有免疫系统,为癌症免疫疗法带来了希望。然而,由于静脉注射时非特异性和全身性激活免疫系统所导致的严重副作用,限制了小分子TLR 激动剂在此类应用中的使用。但是,将小分子咪唑喹啉(IMDQ)TLR7/8 激动剂共价连接到 pH 可降解的聚合物纳米凝胶上,可以显著减少全身炎症反应,同时保留对肿瘤组织及其引流淋巴结的活性。本文介绍了基于聚降冰片烯的酸降解纳米凝胶的合成,用于 IMDQ 的共价连接。完整的纳米凝胶能够充分刺激 TLR7/8 受体,而降解后的可溶性 IMDQ 共轭聚降冰片烯链几乎无法激活 TLR7/8。这使其具有良好的临床安全性,因为降解产物不仅避免了纳米粒子在体内的积累,还提供了非活性的聚合物结合 IMDQ 物种。它们的免疫静默行为保证了空间和时间上对免疫活性的控制,从而有望改善临床应用。