Department of Biopharmaceutics, Kyoto Pharmaceutical University.
Biol Pharm Bull. 2022;45(3):354-359. doi: 10.1248/bpb.b21-00924.
Since probiotic-derived extracellular vesicles (EVs) are capable of activating innate immunity, they are expected to be useful as novel adjuvants. To elucidate the mechanisms underlying the immunostimulatory effects of EVs released from probiotic cells, we newly investigated the role of Toll-like receptor 2 (TLR2) and immune cell downstream signaling in the generation of proinflammatory cytokines. Isolated Bifidobacterium- and Lactobacillus-derived EVs expressed peptidoglycan, one of the major pathogen-associated molecular patterns. EVs particle diameter were approximately 110-120 nm with a negative-zeta potential. The generation of proinflammatory cytokines (tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in TLR2-expressing mouse macrophage-like RAW264.7 cells and mouse dendritic DC2.4 cells treated with Bifidobacterium- and Lactobacillus-derived EVs decreased after the addition of T2.5, a TLR2 inhibitory antibody. Furthermore, we showed that the signaling pathways of c-Jun-NH2-terminal kinase (JNK)/mitogen-activated protein kinases (MAPK) and nuclear factor-kappaB (NF-κB) were also involved in the production of proinflammatory cytokines from EV-treated immune cells. These results provide valuable information for understanding of the host biological function induced by probiotic-derived EVs, which is helpful for developing an EV-based immunotherapeutic system.
由于益生菌衍生的细胞外囊泡（EVs）能够激活先天免疫，因此它们有望成为新型佐剂。为了阐明益生菌细胞释放的 EVs 免疫刺激作用的机制，我们新研究了 Toll 样受体 2（TLR2）和免疫细胞下游信号在促炎细胞因子产生中的作用。分离的双歧杆菌和乳杆菌衍生的 EVs 表达肽聚糖，这是主要的病原体相关分子模式之一。EVs 粒径约为 110-120nm，带负的 Zeta 电位。在 TLR2 表达的鼠巨噬细胞样 RAW264.7 细胞和经双歧杆菌和乳杆菌衍生的 EV 处理的鼠树突状 DC2.4 细胞中，促炎细胞因子（肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6））的产生在用 TLR2 抑制性抗体 T2.5 处理后降低。此外，我们还表明，c-Jun-NH2-末端激酶（JNK）/丝裂原活化蛋白激酶（MAPK）和核因子-κB（NF-κB）信号通路也参与了 EV 处理的免疫细胞中促炎细胞因子的产生。这些结果为理解益生菌衍生的 EV 诱导的宿主生物学功能提供了有价值的信息，这有助于开发基于 EV 的免疫治疗系统。
