ABSTRACT
Cellular drug delivery can improve efficacy and render intracellular pathogens susceptible to compounds that cannot permeate cells. The transport of physiologically active compounds across membranes into target cells can be facilitated by cell-penetrating peptides (CPPs), such as oligoarginines. Here, we investigated whether intracellular delivery of the drug fosmidomycin can be improved by combination with the CPP octaarginine. Fosmidomycin is an antibiotic that inhibits the second reaction in the nonmevalonate pathway of isoprenoid biosynthesis, an essential pathway for many obligate intracellular pathogens, including mycobacteria and apicomplexan parasites. We observed a strict correlation between octaarginine host cell permeability and its ability to improve the efficacy of fosmidomycin.
Plasmodium berghei
liver-stage parasites were only partially susceptible to an octaarginine-fosmidomycin complex. Similarly,
Toxoplasma gondii
was only susceptible during the brief extracellular stages. In marked contrast, a salt complex of octaarginine and fosmidomycin greatly enhanced efficacy against blood-stage
Plasmodium falciparum
. This complex and a covalently linked conjugate of octaarginine and fosmidomycin also reverted resistance of
Mycobacteria
to fosmidomycin. These findings provide chemical genetic evidence for vital roles of the nonmevalonate pathway of isoprenoid biosynthesis in a number of medically relevant pathogens. Our results warrant further investigation of octaarginine as a delivery vehicle and alternative fosmidomycin formulations for malaria and tuberculosis drug development.
摘要
细胞给药可以提高药效,并使细胞内病原体对无法渗透细胞的化合物产生敏感性。细胞穿透肽(CPPs)(如寡精氨酸)可促进生理活性化合物跨膜转运至靶细胞。在此,我们研究了结合 CPP 八精氨酸是否能改善药物吩霉素的细胞内输送。磷霉素是一种抗生素,可抑制异戊二烯类生物合成的非甲基戊二酸途径中的第二反应,而这一途径是包括分枝杆菌和 apicomplexan 寄生虫在内的许多强制性细胞内病原体所必需的。我们观察到,八精氨酸宿主细胞的渗透性与其提高磷霉素疗效的能力之间存在着严格的相关性。
疟原虫
肝期寄生虫仅对八精-osmidomycin 复合物有部分敏感性。同样、
弓形虫
也仅在短暂的细胞外阶段对其敏感。与此形成鲜明对比的是,八精霉素和霉素盐复合物大大提高了对血期
恶性疟原虫
.这种复合物和共价连接的八精霉素和磷霉素轭合物还能逆转霉菌的抗药性。
分枝杆菌
对福美霉素的抗药性。这些发现为异戊二烯类生物合成的非甲基丙酮酸途径在一些医学相关病原体中的重要作用提供了化学遗传学证据。我们的研究结果为进一步研究八精氨酸作为输送载体以及用于疟疾和结核病药物开发的替代性磷霉素制剂提供了依据。