Borges Ellyêssa Nascimento, Freitas E Silva Kleber Santiago, Souza Cardoso Éder Jéferson, Lima Eliana Martins, Mendanha Sebastião Antonio, Alonso Antonio
School of Pharmacy, Federal University of Goiás, Goiânia, GO, Brazil.
FarmaTec - Laboratory for RD&I in Pharmaceutical Nanotechnology and Drug Delivery Systems, Samambaia Technology Park, Goiânia, GO, Brazil.
Arch Biochem Biophys. 2025 Jul;769:110417. doi: 10.1016/j.abb.2025.110417. Epub 2025 Apr 7.
Miltefosine (MTF) and amphotericin B (AmB), drugs approved for leishmaniasis treatment, induce membrane rigidity in Leishmania amazonensis at concentrations that inhibit parasite growth, as demonstrated through spin-probe electron paramagnetic resonance (EPR) spectroscopy. Notably, the rigidity induced by MTF is not due to its direct interaction with the membrane, as shorter incubation periods instead increase fluidity. However, measurements taken following short-term drug exposure reflect conditions before possible oxidative stress has fully developed. AmB causes membrane rigidity, but only at concentration 100 times higher than those causing rigidity after 24 h of exposure. In contrast, oxidative stress-induced membrane rigidity was not observed in macrophages, suggesting that nitric oxide production by these cells may mitigate oxidative damage. Both drugs, however, induced significant membrane rigidity in Leishmania-infected macrophages at concentrations slightly above the IC for amastigotes. EPR data further suggest that oxidative processes can occur within the membranes of the macrophage-amastigote system even without drug exposure. This study also suggests that the primary mechanisms underlying the antileishmanial activity of these two membrane-active drugs are associated with their effects on the cell membrane. Membrane alterations likely lead to ionic imbalances, which may, in turn, disrupt mitochondrial membrane potential and thereby enhance reactive oxygen species (ROS) formation.
米替福新（MTF）和两性霉素B（AmB）是已获批准用于治疗利什曼病的药物，通过自旋探针电子顺磁共振（EPR）光谱法证明，它们在抑制寄生虫生长的浓度下会诱导亚马逊利什曼原虫的膜刚性。值得注意的是，MTF诱导的刚性并非因其与膜的直接相互作用，因为较短的孵育期反而会增加流动性。然而，短期药物暴露后的测量反映的是可能的氧化应激尚未完全发展之前的情况。AmB会导致膜刚性，但仅在比暴露24小时后导致刚性的浓度高100倍的浓度下才会如此。相比之下，在巨噬细胞中未观察到氧化应激诱导的膜刚性，这表明这些细胞产生的一氧化氮可能减轻氧化损伤。然而，两种药物在略高于无鞭毛体IC的浓度下，都会在感染利什曼原虫的巨噬细胞中诱导显著的膜刚性。EPR数据进一步表明，即使没有药物暴露，巨噬细胞-无鞭毛体系统的膜内也可能发生氧化过程。这项研究还表明，这两种膜活性药物的抗利什曼活性的主要机制与其对细胞膜的影响有关。膜改变可能导致离子失衡，进而可能破坏线粒体膜电位，从而增强活性氧（ROS）的形成。
