A Plasmodium falciparum genetic cross reveals the contributions of pfcrt and plasmepsin II/III to piperaquine drug resistance

• Published in: mBio Vol. 15; no. 7; p. e0080524
• Main Authors: Kane, John, Li, Xue, Kumar, Sudhir, Button-Simons, Katrina A, Vendrely Brenneman, Katelyn M, Dahlhoff, Haley, Sievert, Mackenzie A C, Checkley, Lisa A, Shoue, Douglas A, Singh, Puspendra P, Abatiyow, Biley A, Haile, Meseret T, Nair, Shalini, Reyes, Ann, Tripura, Rupam, Peto, Thomas J, Lek, Dysoley, Mukherjee, Angana, Kappe, Stefan H I, Dhorda, Mehul, Nkhoma, Standwell C, Cheeseman, Ian H, Vaughan, Ashley M, Anderson, Timothy J C, Ferdig, Michael T
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 17.07.2024
• Subjects: drug resistance evolution; genetic cross; malaria; Microbial Genetics; piperaquine; Plasmodium falciparum; Research Article; Plasmodium falciparum; malaria; drug resistance evolution; genetic cross; piperaquine
• ISSN: 2150-7511; 2150-7511
• DOI: 10.1128/mbio.00805-24

Piperaquine (PPQ) is widely used in combination with dihydroartemisinin as a first-line treatment against malaria. Multiple genetic drivers of PPQ resistance have been reported, including mutations in the ( ) and increased copies of ( ). We generated a cross between a Cambodia-derived multidrug-resistant KEL1/PLA1 lineage isolate (KH004) and a drug-susceptible Malawian parasite (Mal31). Mal31 harbors a wild-type (3D7-like) allele and a single copy of , while KH004 has a chloroquine-resistant (Dd2-like) allele with an additional G367C substitution and multiple copies of . We recovered 104 unique recombinant parasites and examined a targeted set of progeny representing all possible combinations of variants at and . We performed a detailed analysis of competitive fitness and a range of PPQ susceptibility phenotypes with these progenies, including PPQ survival assay, area under the dose response curve, and a limited point IC . We find that inheritance of the KH004 allele is required for reduced PPQ sensitivity, whereas copy number variation in further decreases susceptibility but does not confer resistance in the absence of additional mutations in . A deep investigation of genotype-phenotype relationships demonstrates that progeny clones from experimental crosses can be used to understand the relative contributions , , and parasite genetic background to a range of PPQ-related traits. Additionally, we find that the resistance phenotype associated with parasites inheriting the G367C substitution in pfcrt is consistent with previously validated PPQ resistance mutations in this transporter.IMPORTANCEResistance to piperaquine, used in combination with dihydroartemisinin, has emerged in Cambodia and threatens to spread to other malaria-endemic regions. Understanding the causal mutations of drug resistance and their impact on parasite fitness is critical for surveillance and intervention and can also reveal new avenues to limiting the evolution and spread of drug resistance. An experimental genetic cross is a powerful tool for pinpointing the genetic determinants of key drug resistance and fitness phenotypes and has the distinct advantage of quantifying the effects of naturally evolved genetic variation. Our study was strengthened since the full range of copies of KH004 was inherited among the progeny clones, allowing us to directly test the role of the copy number on resistance-related phenotypes in the context of a unique allele. Our multigene model suggests an important role for both loci in the evolution of this multidrug-resistant parasite lineage.