Anti-Leishmanial drug therapy faces significant challenges related to cytotoxicity and drug resistance. Thus, new and efficient anti-Leishmanial drugs need to be identified. Due to their broad-spectrum antimicrobial and also immunomodulatory activities, antimicrobial peptides (AMPs) have attracted considerable attention. In this study, we comparatively assessed the anti-Leishmanial activities of two recently identified AMPs (dicentracin-like and moronecidine-like) and the well-known AMP piscidin from the hybrid striped bass. AMPs were first assessed against Leishmania major promastigotes using MTS. Subsequently, macrophages were infected with L. major and treated with AMPs to evaluate anti-amastigotes activity of AMPs, and non-infected macrophages were treated with AMPs to determine cytotoxicity against mammalian cells using MTS. The induction of factors limiting L. major growth (IL-12, TNF-α and reactive oxygen species (ROS)) by AMPs was measured by ELISA and dichlorofluorescin-diacetate (DCFH-DA) assay, respectively. Piscidin was more efficacious against L. major promastigotes as compared to dicentracine-like or moronocidin-like peptides, whereas, dicentracine-like and moronocidin-like peptide exhibited a higher activity against L. major amastigotes compared to piscidin. In turn, piscidin was most cytotoxic in non-infected macrophages compared to the other two AMPs. A direct association was observed between hydrophobicity of AMPs and their anti-promastigote and cytotoxic activities. Dicentracine-like or moronocidin-like peptides induced higher levels of IL-12, TNF-α and ROS in macrophages compared to piscidin. Collectively, our results suggest that dicentracine-like and moronocidin-like peptides represent potentially promising multi-functional therapeutic agents that might not only directly kill L. major but also induce anti-Leishmania factors that can limit L. major growth and intracellular survival.

抗Leishmanial药物疗法面临与细胞毒性和耐药性相关的重大挑战。因此，需要确定新的有效的抗利什曼药物。由于它们的广谱抗菌和免疫调节活性，抗菌肽（AMPs）引起了极大的关注。在这项研究中，我们比较评估了最近鉴定出的两种AMP（敌百丝辛样和莫洛尼西定样）和混合条纹鲈鱼中著名的AMP piscidin的抗Leishmanial活性。首先使用MTS对利什曼原虫主要前鞭毛体进行AMP评估。随后，巨噬细胞被大肠埃希氏菌感染并用AMPs处理以评估AMPs的抗融合活性，并用AMPs处理未感染的巨噬细胞以确定使用MTS对哺乳动物细胞的细胞毒性。分别通过ELISA和二氯二氟荧光素-二乙酸酯（DCFH-DA）测定法测量了由AMPs诱导的限制主要乳酸链球菌生长的因子（IL-12，TNF-α和活性氧（ROS））的诱导。Piscidin反对更有效硕大利什曼原虫相比dicentracine状或moronocidin样肽前鞭毛体，反之，dicentracine样和moronocidin样肽表现出对更高的活性硕大利什曼原虫相比于piscidin，amastigotes。反过来，与其他两种AMP相比，piscidin在未感染的巨噬细胞中最具细胞毒性。观察到AMPs的疏水性与其抗前鞭毛体和细胞毒性活性之间存在直接联系。与辣木素相比，类香茅素或莫罗西汀样肽在巨噬细胞中诱导更高水平的IL-12，TNF-α和ROS水平。总的来说，我们的研究结果表明，dicentracine样和moronocidin样肽代表潜在的有前途的多功能治疗剂不仅可能直接杀死利什曼原虫，而且诱导抗利什曼原虫因素可以限制L.主要生长和细胞内生存。