Department of Bioscience and Biotechnology, Research Institute for Bioactive-Metabolome Network, Konkuk University, Seoul 05029, Korea.
Chuncheon Center, Korea Basic Science Institute, Chuncheon 24341, Korea.
Int J Mol Sci. 2019 Oct 2;20(19):4895. doi: 10.3390/ijms20194895.
Recently, bioactive peptides have attracted attention for their therapeutic applications in the pharmaceutical industry. Among them, antimicrobial peptides are candidates for new antibiotic drugs. Since pseudin-2 (Ps), isolated from the skin of the paradoxical frog , shows broad-spectrum antibacterial activity with high cytotoxicity, we previously designed Ps-K18 with a Lys substitution for Leu in Ps, which showed high antibacterial activity and low toxicity. Here, we examined the potency of Ps-K18, aiming to develop antibiotics derived from bioactive peptides for the treatment of Gram-negative sepsis. We first investigated the antibacterial mechanism of Ps-K18 based on confocal micrographs and field emission scanning electron microscopy, confirming that Ps-K18 targets the bacterial membrane. Anti-inflammatory mechanism of Ps-K18 was investigated by secreted alkaline phosphatase reporter gene assays and RT-PCR, which revealed that Ps-K18 activates innate defense via Toll-like receptor 4-mediated nuclear factor-kappa B signaling pathways. Moreover, we investigated the antiseptic effect of Ps-K18 using a lipopolysaccharide or K1-induced septic shock mouse model. Ps-K18 significantly reduced bacterial growth and inflammatory responses in the septic shock model. Ps-K18 showed low renal and liver toxicity and attenuated lung damage effectively. This study suggests that Ps-K18 is a potent peptide antibiotic that could be applied therapeutically to Gram-negative sepsis.
最近，生物活性肽因其在制药行业的治疗应用而受到关注。其中，抗菌肽是新型抗生素药物的候选者。由于从矛盾蛙皮肤中分离得到的假肽-2（Ps）具有广谱抗菌活性和高细胞毒性，我们之前设计了 Ps-K18，它将 Ps 中的 Leu 替换为 Lys，显示出高抗菌活性和低毒性。在这里，我们研究了 Ps-K18 的效力，旨在开发源自生物活性肽的抗生素来治疗革兰氏阴性菌败血症。我们首先通过共聚焦显微镜和场发射扫描电子显微镜研究了 Ps-K18 的抗菌机制，证实 Ps-K18 靶向细菌膜。通过分泌碱性磷酸酶报告基因检测和 RT-PCR 研究了 Ps-K18 的抗炎机制，结果表明 Ps-K18 通过 Toll 样受体 4 介导的核因子-κB 信号通路激活先天防御。此外，我们使用脂多糖或 K1 诱导的败血症休克小鼠模型研究了 Ps-K18 的抗菌作用。Ps-K18 显著减少了败血症休克模型中的细菌生长和炎症反应。Ps-K18 显示出低肾和肝毒性，并有效减轻了肺损伤。这项研究表明，Ps-K18 是一种有效的肽类抗生素，可应用于治疗革兰氏阴性菌败血症。
