Harada Ayaka, Tsutsuki Hiroyasu, Zhang Tianli, Yahiro Kinnosuke, Sawa Tomohiro, Niidome Takuro
Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan.
Nanomaterials (Basel). 2022 Jun 23;12(13):2161. doi: 10.3390/nano12132161.
Advances in drug delivery systems (DDSs) have enabled the specific delivery of drugs to target cells. Subtilase cytotoxin (SubAB) produced by certain enterohemorrhagic strains induces endoplasmic reticulum (ER) stress and suppresses nitric oxide generation in macrophages. We previously reported that modification of SubAB with poly(D,L-lactide-co-glycolic) acid (PLGA) nanoparticles (SubAB-PLGA NPs) increased intracellular uptake of SubAB and had an anti-inflammatory effect on macrophages. However, specific delivery of SubAB to macrophages could not be achieved because its effects on other cell types were not negligible. Therefore, to suppress non-specific SubAB binding, we used low-binding mutant SubAB (S35A) in which the 35th serine of the B subunit was mutated to alanine. In a macrophage cell line, PLGA NPs modified with S35A (S35A-PLGA NPs) induced ER stress and had anti-inflammatory effects similar to WT-PLGA NPs. However, in an epithelial cell line, S35A-PLGA NPs induced lower ER stress than WT-PLGA NPs. These results suggest that S35A is selectively delivered to macrophages rather than epithelial cells by modification with PLGA NPs and exerts anti-inflammatory effects. Our findings provide a useful technique for protein delivery to macrophages and encourage medical applications of DDSs for the treatment of inflammatory diseases.
药物递送系统（DDSs）的进展使得药物能够特异性地递送至靶细胞。某些肠出血性菌株产生的枯草杆菌蛋白酶细胞毒素（SubAB）可诱导内质网（ER）应激并抑制巨噬细胞中一氧化氮的生成。我们之前报道过，用聚（D，L-丙交酯-共-乙交酯）酸（PLGA）纳米颗粒（SubAB-PLGA NPs）修饰SubAB可增加SubAB的细胞内摄取，并对巨噬细胞具有抗炎作用。然而，由于SubAB对其他细胞类型的影响不可忽略，因此无法实现将SubAB特异性递送至巨噬细胞。因此，为了抑制SubAB的非特异性结合，我们使用了低结合突变体SubAB（S35A），其中B亚基的第35位丝氨酸被突变为丙氨酸。在巨噬细胞系中，用S35A修饰的PLGA NPs（S35A-PLGA NPs）诱导ER应激并具有与野生型PLGA NPs相似的抗炎作用。然而，在上皮细胞系中，S35A-PLGA NPs诱导的ER应激低于野生型PLGA NPs。这些结果表明，通过用PLGA NPs修饰，S35A可选择性地递送至巨噬细胞而非上皮细胞，并发挥抗炎作用。我们的研究结果为蛋白质递送至巨噬细胞提供了一种有用的技术，并促进了DDSs在炎症性疾病治疗中的医学应用。
