ABSTRACT

Chronic bone degenerative diseases represent a major threat to the health and well-being of the population, particularly those with advanced age. This study isolated exosomes (EXO), natural nano-particles, from dendritic cells, the “directors” of the immune response, to examine the immunobiology of DC EXO in mice, and their ability to reprogram immune cells responsible for experimental alveolar bone loss in vivo. Distinct DC EXO subtypes including immune-regulatory (regDC EXO), loaded with TGFB1 and IL10 after purification, along with immune stimulatory (stimDC EXO) and immune “null” immature (iDCs EXO) unmodified after purification, were delivered via I.V. route or locally into the soft tissues overlying the alveolar bone. Locally administrated regDC EXO showed high affinity for inflamed sites, and were taken up by both DCs and T cells in situ. RegDC EXO-encapsulated immunoregulatory cargo (TGFB1 and IL10) was protected from proteolytic degradation. Moreover, maturation of recipient DCs and induction of Th17 effectors was suppressed by regDC EXO, while T-regulatory cell recruitment was promoted, resulting in inhibition of bone resorptive cytokines and reduction in osteoclastic bone loss. This work is the first demonstration of DC exosome-based therapy for a degenerative alveolar bone disease and provides the basis for a novel treatment strategy.

摘要

慢性骨退行性疾病是对人口健康和福祉的主要威胁，尤其是高龄人群。本研究从树突状细胞（免疫反应的“指导者”）中分离出外泌体 (EXO)、天然纳米颗粒，以检查 DC EXO 在小鼠中的免疫生物学，以及它们重新编程导致实验性牙槽骨丢失的免疫细胞的能力体内. 不同的 DC EXO 亚型，包括免疫调节型 (regDC EXO)，纯化后装载 TGFB1 和 IL10，以及纯化后未修饰的免疫刺激型 (stimDC EXO) 和免疫“无效”未成熟型 (iDCs EXO)，通过 IV 途径或局部递送进入覆盖牙槽骨的软组织。局部给药的 regDC EXO 对炎症部位表现出高亲和力，并被 DCs 和 T 细胞原位吸收. RegDC EXO 封装的免疫调节货物（TGFB1 和 IL10）受到保护免受蛋白水解降解。此外，regDC EXO 抑制受体 DC 的成熟和 Th17 效应子的诱导，同时促进 T 调节细胞募集，从而抑制骨吸收细胞因子和减少破骨细胞骨丢失。这项工作首次展示了基于 DC 外泌体的退行性牙槽骨疾病治疗，并为新的治疗策略提供了基础。