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Lumefantrine pressure selects nonsynonymous mutation in cysteine desulfurase IscS gene in the rodent malaria parasite Plasmodium berghei ANKA

Background: Lumefantrine (LM), piperaquine (PQ), and amodiaquine (AQ) are the essential long-acting partner drugs in the artemisinin-based combination therapies (ACTs) treatment regimens globally. Understanding the resistance mechanisms to partner drugs remains critical for tracking resistant parasites. Cysteine desulfurase IscS (nfs1), one of the proteins involved in the iron-sulfur (FeS) biogenesis pathway, has been implicated in mediating malaria parasite drug resistance.   Methods: Using the rodent malaria parasites Plasmodium berghei ANKA in mice, we assessed whether the nfs1 gene is associated with LM, PQ, and AQ resistance. By means of PCR and sequencing analysis, we probed for single nucleotide polymorphisms (SNPs) within the nfs1 gene. Using qPCR, we then measured the expression of the nfs1 gene in resistant parasites relative to the drug-sensitive parent parasites.  Results: Our analyses of nfs1 reveal a non-synonymous Gln142Arg mutation in the LM and PQ-resistant parasites. This mutation was not detected in the AQ-resistant parasites. The mRNA quantification of the nfs1 gene reveals significant downregulation in both LM and PQ-resistant parasites compared to the drug-sensitive wild-type (WT) parasites. Conversely, nfs1 expression was upregulated in the AQ-resistant schizont stage compared to the WT parasites.   Conclusion: Our data suggest that LM and PQ selection pressure induces nonsynonymous mutation and nfs1 downregulation of its expression in Plasmodium berghei. Collectively, these findings provide a premise for investigating LM and PQ resistance mechanisms in both P. berghei and P. falciparum.