In the continuing search for novel antibiotics, antimicrobial peptides are promising molecules, due to different mechanisms of action compared to classic antibiotics and to their selectivity for interaction with microorganism cells rather than with mammalian cells. Previously, our research group has isolated the antimicrobial peptide LyeTx I from the venom of the spider Lycosa erythrognatha. Here, we proposed to synthesize three novel shortened derivatives from LyeTx I (LyeTx I mn; LyeTx I mnΔK; LyeTx I mnΔKAc) and to evaluate their toxicity and biological activity as potential antimicrobial agents. Peptides were synthetized by Fmoc strategy and circular dichroism analysis was performed, showing that the three novel shortened derivatives may present membranolytic activity, like the original LyeTx I, once they folded as an alpha helix in 2.2.2-trifluorethanol and sodium dodecyl sulfate. In vitro assays revealed that the shortened derivative LyeTx I mnΔK presents the best score between antimicrobial (↓ MIC) and hemolytic (↑ EC₅₀) activities among the synthetized shortened derivatives, and LUHMES cell-based NeuriTox test showed that it is less neurotoxic than the original LyeTx I (EC₅₀ [LyeTx I mnΔK] ⋙ EC₅₀ [LyeTx I]). In vivo data, obtained in a mouse model of septic arthritis induced by Staphylococcus aureus, showed that LyeTx I mnΔK is able to reduce infection, as demonstrated by bacterial recovery assay (∼10-fold reduction) and scintigraphic imaging (less technetium-99m labeled-Ceftizoxime uptake by infectious site). Infection reduction led to inflammatory process and pain decreases, as shown by immune cells recruitment reduction and threshold nociception increment, when compared to positive control group. Therefore, among the three shortened peptide derivatives, LyeTx I mnΔK is the best candidate as antimicrobial agent, due to its smaller amino acid sequence and toxicity, and its greater biological activity.

在不断寻找新型抗生素的过程中，抗菌肽是有前途的分子，因为与经典抗生素相比，其作用机制不同，而且它们对与微生物细胞而不是与哺乳动物细胞相互作用的选择性。此前，我们课题组从红颌狼蛛的毒液中分离出了抗菌肽LyeTx I。在这里，我们建议合成 LyeTx I 的三种新型缩短衍生物（LyeTx I mn；LyeTx I mnΔK；LyeTx I mnΔKAc），并评估它们作为潜在抗菌剂的毒性和生物活性。通过Fmoc策略合成肽并进行圆二色性分析，表明这三种新型缩短的衍生物一旦在2.2.2-三氟乙醇和十二烷基硫酸钠中折叠成α螺旋，就可能呈现出膜溶解活性，就像原始的LyeTx I一样。体外试验显示，缩短的衍生物 LyeTx I mnΔK 在合成的缩短的衍生物中抗菌 (↓ MIC) 和溶血 (↑ EC ₅₀ ) 活性之间表现出最佳得分，并且基于 LUHMES 细胞的 NeuriTox 测试表明，它的神经毒性比原始 LyeTx I（EC ₅₀ [LyeTx I mnΔK] ⋙ EC ₅₀ [LyeTx I]）。在金黄色葡萄球菌诱导的化脓性关节炎小鼠模型中获得的体内数据表明，LyeTx I mnΔK 能够减少感染，如细菌回收测定（减少约 10 倍）和闪烁成像（较少的 Technetium-99m 标记）所证明的那样。 -感染部位对头孢唑肟的吸收）。与阳性对照组相比，感染减少导致炎症过程和疼痛减轻，如免疫细胞招募减少和伤害感受阈值增加所示。因此，在三种短肽衍生物中，LyeTx I mnΔK 因其更小的氨基酸序列和毒性以及更大的生物活性而成为抗菌剂的最佳候选者。