Heller Laura E, Goggins Eibhlin, Roepe Paul D
Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States.
Biochemistry. 2018 Dec 26;57(51):6935-6945. doi: 10.1021/acs.biochem.8b00960. Epub 2018 Dec 13.
Previously (Heller, L. E., and Roepe, P. D. Quantification of Free Ferriprotoporphyrin IX Heme and Hemozoin for Artemisinin Sensitive versus Delayed Clearance Phenotype Plasmodium falciparum Malarial Parasites. Biochemistry, DOI: 10.1021/acs.biochem.8b00959, preceding paper in this issue), we quantified free ferriprotoporphyrin IX (FPIX) heme abundance for control versus delayed clearance phenotype (DCP) intraerythrocytic Plasmodium falciparum malarial parasites. Because artemisinin drugs are activated by free FPIX, these data predict that the abundance of long-hypothesized toxic artemisinin drug-FPIX covalent adducts might differ for control versus DCP parasites. If so, this would have important repercussions for understanding the mechanism of the DCP, also known as emerging artemisinin resistance. To test these predictions, we studied in vitro formation of FPIX-dihydroartemisinin (DHA) adducts and then for the first time quantified the abundance of FPIX-DHA adducts formed within live P. falciparum versus the stage of intraerythrocytic development. Using matched isogenic parasite strains, we quantified the adduct for DCP versus control parasite strains and found that mutant PfK13 mediates lower adduct abundance for DCP parasites. The results suggest improved models for the molecular pharmacology of artemisinin-based antimalarial drugs and the molecular mechanism of the DCP.
此前（赫勒，L.E.，和罗普，P.D.青蒿素敏感与清除延迟表型恶性疟原虫中游离铁原卟啉IX血红素和疟色素的定量分析。《生物化学》，DOI: 10.1021/acs.biochem.8b00959，本期前一篇论文），我们对对照和清除延迟表型（DCP）的红细胞内恶性疟原虫的游离铁原卟啉IX（FPIX）血红素丰度进行了定量分析。由于青蒿素类药物由游离FPIX激活，这些数据预测，长期以来假设的有毒青蒿素药物-FPIX共价加合物的丰度在对照寄生虫和DCP寄生虫中可能有所不同。如果是这样，这将对理解DCP的机制产生重要影响，DCP也被称为新出现的青蒿素耐药性。为了验证这些预测，我们研究了FPIX-双氢青蒿素（DHA）加合物的体外形成，然后首次定量了在活的恶性疟原虫内形成的FPIX-DHA加合物的丰度以及红细胞内发育阶段的情况。使用匹配的同基因寄生虫株，我们对DCP寄生虫株和对照寄生虫株的加合物进行了定量，发现突变型PfK13介导的DCP寄生虫加合物丰度较低。这些结果为基于青蒿素的抗疟药物的分子药理学和DCP的分子机制提供了改进的模型。
