ABSTRACT

Objectives: The aim of the study was to design and synthesise novel lactotransferrin-derived antimicrobial peptides (AMPs) with enhanced antibacterial activity against cariogenic bacteria.

Methods: We obtained the LF-1 (WKLLRKAWKLLRKA) and LF-2 (GKLIWKLLRKAWKLLRKA) AMPs, based on the N-terminal functional sequence of lactotransferrin, and characterised their physicochemical properties and secondary structure. Their antibacterial activity against caries-associated bacteria was evaluated using bacterial susceptibility and time-killing assays, as well as transmission electron microscopy (TEM). The antibiofilm activity against Streptococcus mutans biofilms was determined using biofilm susceptibility assays and confocal laser scanning microscopy (CLSM). A rodent model of dental caries was adopted to evaluate their anticaries effectiveness in vivo.

Results: Both peptides possessed an α-helical structure with excellent amphipathicity. LF-1 was effective against S. mutans and Actinomyces species, whereas LF-2 showed more potent antibacterial activity than LF-1 against a broader spectrum of tested strains. Both peptides inhibited the formation of S. mutans biofilm starting at 8 μmol/L and exerted effective eradication of S. mutans in preformed biofilms. Both peptides exhibited satisfactory biocompatibility and exerted significant anticaries effects in a rodent model.

Conclusions: Both lactotransferrin-derived peptides displayed strong antimicrobial activity against cariogenic bacteria and S. mutans biofilm in vitro and effectively inhibited dental caries in vivo.

摘要

目的：该研究的目的是设计和合成新型乳转铁蛋白衍生的抗菌肽 (AMP)，其对致龋菌具有增强的抗菌活性。

方法：我们基于乳转铁蛋白的 N 端功能序列获得了 LF-1 (WKLLRKAWKLLRKA) 和 LF-2 (GKLIWKLLRKAWKLLRKA) AMP，并表征了它们的理化性质和二级结构。使用细菌敏感性和时间杀伤试验以及透射电子显微镜 (TEM) 评估了它们对龋齿相关细菌的抗菌活性。使用生物膜敏感性测定和共聚焦激光扫描显微镜 (CLSM) 确定了对变形链球菌生物膜的抗生物膜活性。采用啮齿动物龋齿模型评价其体内抗龋效果。

结果：两种肽均具有α-螺旋结构，具有优异的两亲性。LF-1 对S. mutans和放线菌种有效，而 LF-2 对更广谱的测试菌株显示出比 LF-1 更强的抗菌活性。两种肽从 8 μmol/L 开始抑制变形链球菌生物膜的形成，并有效根除预形成的生物膜中的变形链球菌。这两种肽都表现出令人满意的生物相容性，并在啮齿动物模型中发挥了显着的抗龋作用。

结论S：两种乳运衍生肽显示对抗致龋菌和强抗菌活性的变异链球菌生物膜体外和有效地抑制龋齿体内。