Background Piperaquine, used in combination with dihydroartemisinin, has been identified as a promising partner drug for uncomplicated treatment and chemoprevention of Plasmodium falciparum malaria in Africa. In light of the earlier spread of piperaquine resistance in Southeast Asia, mediated primarily by mutations in the drug efflux transporter PfCRT, we have explored whether PfCRT mutations would represent a probable path to piperaquine resistance becoming established in Africa. Methods We edited PfCRT mutations known to mediate piperaquine resistance in Southeast Asia into P. falciparum asexual blood stage parasites expressing three prevalent African mutant PfCRT haplotypes. Gene-edited clones were profiled in antimalarial concentration-response and competitive fitness assays. Results pfcrt-edited parasites expressing the contemporary Southeast Asian T93S or I218F mutations added to the GB4 and Cam783 haplotypes common in Africa did not mediate piperaquine resistance, with partial survival only at low drug concentrations. In contrast, parasites expressing these mutations on the rare PfCRT FCB haplotype, observed mostly in North-East Africa, acquired a moderate level of piperaquine resistance. Dd2GB4, Dd2Cam783, and Dd2FCB lines edited to express the T93S or I218F mutations showed increased susceptibility to chloroquine. Piperaquine-resistant African PfCRT isoforms conferred a substantial fitness cost, manifesting as reduced asexual blood stage parasite growth rates. Conclusions These findings suggest that piperaquine-resistant PfCRT mutations that emerged in Southeast Asia mediate resistance only in a limited subset of African PfCRT haplotypes, with fitness costs that we suspect would likely preclude dissemination in high-transmission malaria-endemic African regions.

中文翻译：

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有利于哌喹耐药性的恶性疟原虫非洲 PfCRT 突变亚型并不常见，并且会带来很大的适应成本


背景 哌喹与双氢青蒿素联合使用，已被确定为非洲恶性疟原虫疟疾简单治疗和化学预防的有前途的合作伙伴药物。鉴于哌喹耐药性在东南亚的早期传播，主要由药物外排转运蛋白 PfCRT 的突变介导，我们探讨了 PfCRT 突变是否代表哌喹耐药性在非洲建立的可能途径。方法 我们将已知介导东南亚哌喹耐药性的 PfCRT 突变编辑成表达三种普遍非洲突变 PfCRT 单倍型的恶性疟原虫无性血期寄生虫。在抗疟药浓度反应和竞争性健身测定中分析基因编辑克隆。结果 表达当代东南亚 T93S 或 I218F 突变的 pfcrt 编辑寄生虫添加到非洲常见的 GB4 和 Cam783 单倍型中，不介导哌喹耐药，仅在低药物浓度下部分存活。相比之下，在罕见的 PfCRT FCB 单倍型上表达这些突变的寄生虫（主要在东北非观察到）获得了中等水平的哌喹耐药性。编辑表达 T93S 或 I218F 突变的 Dd2GB4 、 Dd2Cam783 和 Dd2FCB 细胞系显示对氯喹的敏感性增加。耐哌喹的非洲 PfCRT 亚型赋予了巨大的健身成本，表现为无性血期寄生虫生长速率降低。结论 这些发现表明，东南亚出现的哌喹耐药 PfCRT 突变仅在有限的非洲 PfCRT 单倍型子集中介导耐药性，我们怀疑其适应成本可能会阻止在疟疾高传播地区的非洲流行地区传播。