Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School Jerusalem, Israel.
Front Microbiol. 2014 Dec 9;5:673. doi: 10.3389/fmicb.2014.00673. eCollection 2014.
The discovery and therapeutic use of antibiotics made a major contribution to the reduction of human morbidity and mortality. However, the growing resistance to antibiotics has become a matter of huge concern. In this study we aimed to develop an innovative approach to treat bacterial infections utilizing two components: the human antibacterial peptide β-defensin-3 (BD3) and the bacterial protein flagellin (F). This combination was designed to provide an efficient weapon against bacterial infections with the peptide killing the bacteria directly, while the flagellin protein triggers the immune system and acts against bacteria escaping from the peptide's action. We designed, expressed and purified the fusion protein flagellin BD3 (FBD3) and its two components, the F protein and the native BD3 peptide. FBD3 fusion protein and native BD3 peptide had antibacterial activity in vitro against various bacterial strains. FBD3 and F proteins could also recognize their receptor expressed on target cells and stimulated secretion of IL-8. In addition, F and FBD3 proteins had a partial protective effect in mice infected by pathogenic Escherichia coli bacteria that cause a lethal disease. Moreover, we were able to show partial protection of mice infected with E. coli using a flagellin sequence from Salmonella. We also explored flagellin's basic mechanisms of action, focusing on its effects on CD4+ T cells from healthy donors. We found that F stimulation caused an increase in the mRNA levels of the Th1 response cytokines IL12A and IFNγ. In addition, F stimulation affected its own receptor.
抗生素的发现和治疗用途为降低人类发病率和死亡率做出了重大贡献。然而，抗生素耐药性的不断增加已成为一个巨大的问题。在这项研究中，我们旨在开发一种创新方法来利用两种成分治疗细菌感染：人抗菌肽β-防御素-3 (BD3) 和细菌蛋白鞭毛蛋白 (F)。这种组合旨在提供一种对抗细菌感染的有效武器，肽直接杀死细菌，而鞭毛蛋白触发免疫系统并对抗从肽的作用中逃脱的细菌。我们设计、表达和纯化了融合蛋白鞭毛蛋白 BD3 (FBD3) 及其两种成分，即 F 蛋白和天然 BD3 肽。FBD3 融合蛋白和天然 BD3 肽在体外对各种细菌菌株均具有抗菌活性。FBD3 和 F 蛋白还可以识别其在靶细胞上表达的受体，并刺激 IL-8 的分泌。此外，F 和 FBD3 蛋白对感染致病性大肠杆菌的小鼠具有部分保护作用，大肠杆菌可导致致命疾病。此外，我们能够使用来自沙门氏菌的鞭毛蛋白序列显示对感染大肠杆菌的小鼠具有部分保护作用。我们还研究了鞭毛蛋白的基本作用机制，重点关注其对健康供体 CD4+T 细胞的影响。我们发现 F 刺激导致 Th1 反应细胞因子 IL12A 和 IFNγ 的 mRNA 水平增加。此外，F 刺激还影响其自身的受体。
