Kers Johan A, Sharp Robert E, Defusco Anthony W, Park Jae H, Xu Jin, Pulse Mark E, Weiss William J, Handfield Martin
Industrial Products Division, Intrexon Corp., South San Francisco, CA, United States.
Oragenics, Inc., Tampa, FL, United States.
Front Microbiol. 2018 Mar 16;9:415. doi: 10.3389/fmicb.2018.00415. eCollection 2018.
Lantibiotics offer an untapped pipeline for the development of novel antibiotics to treat serious Gram-positive (+) infections including . Mutacin 1140 (MU1140) is a lantibiotic produced by and acts via a novel mechanism of action, which may limit the development of resistance. This study sought to identify a lead compound for the treatment of associated diarrhea (CDAD). Compounds were selected from a saturation mutagenesis library of 418 single amino acid variants of MU1140. Compounds were produced by small scale fermentation, purified, characterized and then subjected to a panel of assays aimed at identifying the best performers. The screening assays included: susceptibility testing [MIC against , , vancomycin-resistant enterococci (VRE), , , , and ; cytotoxicity screening on HepG2 hepatocytes; pharmacological profiling with the Safety Screen 44, metabolic and chemical stability in biologically relevant fluids (FaSSGF, FaSSIF and serum); and efficacy ]. Several lantibiotic compounds had better MIC against , compared to vancomycin, but not against other bacterial species tested. The Safety Screen 44 pharmacological profiling assay suggested that this class of compounds has relatively low overall toxicity and that compound OG253 (MU1140, Phe1Ile) is not likely to present inadvertent off-target effects, as evidenced by a low promiscuity score. The cytotoxicity assay also indicated that this class of compounds was characterized by low toxicity; the EC of OG253 was 636 mg/mL on HepG2 cells. The half-life in simulated gastric fluid was >240 min. for all compound tested. The stability in simulated intestinal fluid ranged between a half-life of 5 min to >240 min, and paralleled the half-life in serum. OG253 ultimately emerged as the lead compound based on superior efficacy along with an apparent lack of relapse in a hamster model of infection. The lessons learned from this report are applicable to therapeutic lanthipeptides in general and may assist in the design of novel molecules with improved pharmacological, therapeutic and physicochemical profiles. The data presented also support the continued clinical development of OG253 as a novel antibiotic against CDAD that could prevent recurrence of the infection.
羊毛硫抗生素为开发用于治疗严重革兰氏阳性（+）感染的新型抗生素提供了一个尚未开发的途径。变链菌素1140（MU1140）是由[具体产生菌未提及]产生的一种羊毛硫抗生素，其作用机制新颖，可能会限制耐药性的产生。本研究旨在确定一种用于治疗艰难梭菌相关性腹泻（CDAD）的先导化合物。化合物是从MU1140的418个单氨基酸变体的饱和诱变文库中筛选出来的。通过小规模发酵生产化合物，进行纯化、表征，然后进行一系列旨在鉴定最佳性能者的测定。筛选测定包括：对[多种细菌未提及]的药敏试验[最低抑菌浓度（MIC）]、对耐万古霉素肠球菌（VRE）、[多种细菌未提及]、[多种细菌未提及]、[多种细菌未提及]和[多种细菌未提及]的MIC；对HepG2肝细胞的细胞毒性筛选；使用安全筛选44进行药理学分析、在生物相关流体（FaSSGF、FaSSIF和血清）中的代谢和化学稳定性；以及疗效[具体疗效未提及]。与万古霉素相比，几种羊毛硫抗生素化合物对[多种细菌未提及]的MIC更好，但对其他测试细菌种类则不然。安全筛选44药理学分析试验表明，这类化合物总体毒性相对较低，并且化合物OG253（MU1140，苯丙氨酸1异亮氨酸）不太可能产生意外的脱靶效应，低混杂性评分证明了这一点。对[具体细胞未提及]的细胞毒性测定也表明，这类化合物的特点是毒性低；OG253在HepG2细胞上的半数有效浓度（EC）为636mg/mL。所有测试化合物在模拟胃液中的半衰期均>240分钟。在模拟肠液中的稳定性范围为半衰期5分钟至>240分钟，与血清中的半衰期相似。基于在仓鼠感染模型中卓越的[具体疗效未提及]疗效以及明显缺乏复发情况，OG253最终成为先导化合物。本报告中吸取的经验教训一般适用于治疗性羊毛硫肽，可能有助于设计具有改善的药理学、治疗学和物理化学特性的新型分子。所呈现的数据也支持将OG253作为一种针对CDAD的新型抗生素继续进行临床开发，该抗生素可预防感染复发。
