The Malaria Parasite's Lactate Transporter PfFNT Is the Target of Antiplasmodial Compounds Identified in Whole Cell Phenotypic Screens.
The Malaria Parasite's Lactate Transporter PfFNT Is the Target of Antiplasmodial Compounds Identified in Whole Cell Phenotypic Screens.
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DOI：
10.1371/journal.ppat.1006180
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发表时间：
2017-02
期刊：
影响因子：
6.7
通讯作者：
Lehane AM
中科院分区：
文献类型：
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作者：
Hapuarachchi SV;Cobbold SA;Shafik SH;Dennis AS;McConville MJ;Martin RE;Kirk K;Lehane AM
在这项研究中，我们对包含400种具有抗疟活性的化合物的“疟疾盒子”化学文库进行了筛选，以寻找扰乱疟疾寄生虫恶性疟原虫内部pH的化合物。15种化合物诱导了寄生虫胞质的酸化。其中两个是通过抑制寄生虫的甲酸盐亚硝酸盐转运蛋白(PfFNT)来实现的，PfFNT介导了寄生虫通过糖酵解产生的乳酸的H+偶联外流。这两种化合物均能抑制乳酸通过寄生虫质膜的转运，并抑制非洲爪哇卵母细胞表达的PfFNT对乳酸的转运。抑制PfFNT可引起寄生虫红细胞中乳酸的积累，以及寄生虫和寄生虫红细胞的肿胀。寄生虫长期暴露于其中一种抑制剂会导致具有PfFNT突变形式的抗药性寄生虫，该突变形式显示出抑制剂敏感性降低。这项研究首次证明PfFNT是一种可用药的抗疟疾靶点。对主要抗疟疾药物产生抗药性的恶性疟原虫菌株的出现和传播，加剧了发现和开发通过新机制杀死这种寄生虫的药物的必要性。在这里，我们筛选了已知的抑制恶性疟原虫生长的化合物，以了解它们对寄生虫体内pH的影响。我们鉴定了15种降低寄生虫体内pH值的化合物，并确定了其中两种化合物MMV007839和MMV000972扰乱pH值并杀死寄生虫的机制。这两个化合物被发现抑制恶性疟原虫甲酸盐亚硝酸盐转运蛋白(PfFNT)，PfFNT是一种位于寄生虫表面的转运蛋白，用于从寄生虫中清除废弃的乳酸。这些化合物既抑制了H+偶联的乳酸跨寄生虫质膜的转运，也抑制了非洲爪哇卵母细胞表达的PfFNT对乳酸的转运。除了破坏pH，PfFNT抑制还会导致寄生虫感染的红细胞中乳酸的积聚，以及寄生虫和受感染的红细胞的肿胀。长期暴露在MMV007839下的寄生虫会产生对该化合物不太敏感的PfFNT突变形式的抗药性寄生虫。这项研究证实PfFNT是一种新的抗疟疾药物靶点。
In this study the ‘Malaria Box’ chemical library comprising 400 compounds with antiplasmodial activity was screened for compounds that perturb the internal pH of the malaria parasite, Plasmodium falciparum. Fifteen compounds induced an acidification of the parasite cytosol. Two of these did so by inhibiting the parasite’s formate nitrite transporter (PfFNT), which mediates the H+-coupled efflux from the parasite of lactate generated by glycolysis. Both compounds were shown to inhibit lactate transport across the parasite plasma membrane, and the transport of lactate by PfFNT expressed in Xenopus laevis oocytes. PfFNT inhibition caused accumulation of lactate in parasitised erythrocytes, and swelling of both the parasite and parasitised erythrocyte. Long-term exposure of parasites to one of the inhibitors gave rise to resistant parasites with a mutant form of PfFNT that showed reduced inhibitor sensitivity. This study provides the first evidence that PfFNT is a druggable antimalarial target. The emergence and spread of Plasmodium falciparum strains resistant to leading antimalarial drugs has intensified the need to discover and develop drugs that kill the parasite via new mechanisms. Here we screened compounds that are known to inhibit P. falciparum growth for their effects on the pH inside the parasite. We identified fifteen compounds that decrease the pH inside the parasite, and determined the mechanism by which two of these, MMV007839 and MMV000972, disrupt pH and kill the parasite. The two compounds were found to inhibit the P. falciparum formate nitrite transporter (PfFNT), a transport protein that is located on the parasite surface and that serves to remove the waste product lactic acid from the parasite. The compounds inhibited both the H+-coupled transport of lactate across the parasite plasma membrane and the transport of lactate by PfFNT expressed in Xenopus oocytes. In addition to disrupting pH, PfFNT inhibition led to a build-up of lactate in the parasite-infected red blood cell and the swelling of both the parasite and the infected red blood cell. Exposing parasites to MMV007839 over a prolonged time period gave rise to resistant parasites with a mutant form of PfFNT that was less sensitive to the compound. This study validates PfFNT as a novel antimalarial drug target.