Efficacy of Lumefantrine against piperaquine resistant Plasmodium berghei parasites is selectively restored by probenecid, verapamil, and cyproheptadine through ferredoxin NADP + -reductase and cysteine desulfurase

The ability of the human malaria parasite, to develop resistance against mainstay drugs remains a public health problem. Currently, the antimalarial drugs, lumefantrine (LM), and piperaquine (PQ) are essential components of the mainstay artemisinin-based therapies used for the treatment of malaria globally. Here, we used a model parasite to investigate the mechanisms of LM and PQ resistance. We employed known resistance reversing agents (RA): probenecid, verapamil, or cyproheptadine to study the mechanisms of LM and PQ resistance in the standard 4-day suppressive test. We then employed reverse genetics to assess the impact of deleting or over-expressing plausible genes associated with the metabolism and transport of drugs. We show that only, cyproheptadine at 5mgkg restored LM activity by above 65% against LM-resistant parasites (LM) but failed to reinstate PQ activity against PQ-resistant parasites (PQ). Whereas the PQ had lost significant susceptibility to LM, the three RA, cyproheptadine verapamil, and probenecid restored LM potency by above 70%, 60%, and 55% respectively against the PQ. We thus focused on the mechanisms of LM resistance in PQ. Here we show the partial deletion of the cysteine desulfurase (SUFS) and overexpression of the Ferredoxin NADP+ reductase (FNR) genes in the PQ parasite achieved two results; i) abolished the impact of RA on LM activity; ii) restored the susceptibility of PQ to LM alone. Our findings associated SUFS and FNR protein with the action of LM and RA action in We demonstrate that the incorporation of any of the RA into an antimalarial combination that comprises LM would augment LM activity and concomitantly antagonize the emergence of LM resistance derived from PQ pressure. The impact of RA, deletion of SUFS, and overexpression of FNR on LM activity need to be tested in .