目的:设计一种新的酸活化抗菌肽。
背景:龋齿是一种与微生物生物膜感染相关的口腔疾病。致龋细菌的代谢活性导致菌斑生物膜的pH降低,导致牙齿脱矿。这种酸性环境有利于对强酸具有高度抗性的致龋细菌的生长,which,反过来,产生更多的酸,导致斑块生物膜的pH进一步降低。因此,利用酸性牙菌斑微环境防治龋病的策略已成为近年来研究的热点,例如开发pH敏感的药物递送系统。
目的:设计并合成具有GWHFFHFFHFF序列的酸靶向抗菌肽。
方法:最小抑制浓度(MIC)和最小细菌浓度(MBC)测试证实了其抗菌活性。碘化丙啶(PI)染色用于检测核酸渗漏。通过生物膜抑制测定法测定抗生物膜活性。光毒性研究证实了PPIX-P12的光毒性。
结果:MIC和MBC检测证实P12具有酸激活的抗变形链球菌活性。杀菌动力学实验和碘化丙啶(PI)染色实验表明,P12杀死了浮游变形链球菌UA159细胞,导致酸性介质中核酸的泄漏。此外,P12在早期和成熟生物膜阶段显示出酸活化的抗生物膜。P12与光治疗剂原卟啉IX(PpIX)缀合以构建原卟啉衍生物PpIX-P12。体外实验表明,PpIX-P12在pH5.5培养基中表现出比在pH7.2培养基中更好的抗菌活性。
结论:结论:我们设计了一种酸激活的AMP,在中性pH下没有抗菌活性,但在酸性pH值下具有抗菌活性。
BACKGROUND: Dental caries is an oral disease associated with infection by microbial biofilm. The metabolic activity of cariogenic bacteria results in a pH decrease in the plaque biofilm, causing tooth demineralization. This acidic environment favors the growth of cariogenic bacteria that are highly resistant to strong acids, which, in turn, produce more acid resulting in a further decrease in the pH of the plaque biofilm. Therefore, the strategy of utilizing the acidic dental plaque microenvironment to prevent and treat dental caries has become a hot research topic in recent years, such as the development of pH-sensitive drug delivery systems.
OBJECTIVE: Design of a new acid-activated antibacterial peptide.
OBJECTIVE: To design and synthesis an acid targeted antimicrobial peptide with the GWHHFFHFFHFF sequence.
METHODS: Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) testing confirmed its antibacterial activity. Propidium iodide (PI) staining was used to detect nucleic acid leakage. Determination of anti-biofilm activity by biofilm inhibition assay. A phototoxicity study confirmed the phototoxicity of PPIX-P12.
RESULTS: MIC and MBC testing confirmed that P12 possessed acid-activated anti-Streptococcus mutans activity. Bactericidal kinetic experiments and propidium iodide (PI) staining experiments showed that P12 killed planktonic S. mutans UA159 cells leading to the leakage of nucleic acids in the acidic medium. Moreover, P12 showed acid-activated anti-biofilms at the early and mature biofilm stages. P12 was conjugated with the phototherapeutic agent protoporphyrin IX (PpIX) to construct the protoporphyrin derivative PpIX-P12. In vitro experiments revealed that PpIX-P12 displayed better antibacterial activity in pH 5.5 medium than in pH 7.2 medium.
CONCLUSIONS: In conclusion, we designed an acid-activated AMP, which had no antimicrobial activity at neutral pH, but had antimicrobial activity at an acidic pH.