Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
Department of Internal Medicine, Division of Infectious Diseases, College of Medicine, Korea University Anam Hospital, Korea University, Seoul 02841, Korea.
Int J Mol Sci. 2021 Nov 20;22(22):12520. doi: 10.3390/ijms222212520.
Carbapenem-resistant (CRAB) infection can cause acute host reactions that lead to high-fatality sepsis, making it important to develop new therapeutic options. Previously, we developed a short 9-meric peptide, Pro9-3D, with significant antibacterial and cytotoxic effects. In this study, we attempted to produce safer peptide antibiotics against CRAB by reversing the parent sequence to generate R-Pro9-3 and R-Pro9-3D. Among the tested peptides, R-Pro9-3D had the most rapid and effective antibacterial activity against Gram-negative bacteria, particularly clinical CRAB isolates. Analyses of antimicrobial mechanisms based on lipopolysaccharide (LPS)-neutralization, LPS binding, and membrane depolarization, as well as SEM ultrastructural investigations, revealed that R-Pro9-3D binds strongly to LPS and impairs the membrane integrity of CRAB by effectively permeabilizing its outer membrane. R-Pro9-3D was also less cytotoxic and had better proteolytic stability than Pro9-3D and killed biofilm forming CRAB. As an LPS-neutralizing peptide, R-Pro9-3D effectively reduced LPS-induced pro-inflammatory cytokine levels in RAW 264.7 cells. The antiseptic abilities of R-Pro9-3D were also investigated using a mouse model of CRAB-induced sepsis, which revealed that R-Pro9-3D reduced multiple organ damage and attenuated systemic infection by acting as an antibacterial and immunosuppressive agent. Thus, R-Pro9-3D displays potential as a novel antiseptic peptide for treating Gram-negative CRAB infections.
耐碳青霉烯类抗生素 （CRAB） 感染可引起急性宿主反应，导致高病死率脓毒症，因此开发新的治疗方法非常重要。先前，我们开发了一种具有显著抗菌和细胞毒性作用的短 9 肽 Pro9-3D。在这项研究中，我们试图通过反转亲本序列来生成 R-Pro9-3 和 R-Pro9-3D，从而产生针对 CRAB 的更安全的肽类抗生素。在测试的肽中，R-Pro9-3D 对革兰氏阴性菌，尤其是临床 CRAB 分离株具有最快和最有效的抗菌活性。基于脂多糖 （LPS） 中和、LPS 结合和膜去极化的抗菌机制分析以及 SEM 超微结构研究表明，R-Pro9-3D 与 LPS 强烈结合，并通过有效破坏其外膜来损害 CRAB 的膜完整性。与 Pro9-3D 相比，R-Pro9-3D 的细胞毒性更低，且具有更好的蛋白水解稳定性，并能杀死形成生物膜的 CRAB。作为一种 LPS 中和肽，R-Pro9-3D 可有效降低 LPS 诱导的 RAW 264.7 细胞中促炎细胞因子的水平。还使用 CRAB 诱导的脓毒症小鼠模型研究了 R-Pro9-3D 的防腐能力，结果表明 R-Pro9-3D 通过作为抗菌和免疫抑制剂来减少多个器官损伤并减轻全身感染。因此，R-Pro9-3D 具有作为治疗革兰氏阴性 CRAB 感染的新型防腐肽的潜力。
