The antimalarial drug primaquine targets Fe–S cluster proteins and yeast respiratory growth

Abstract

Malaria is a major health burden in tropical and subtropical countries. The antimalarial drug primaquine is extremely useful for killing the transmissible gametocyte forms of Plasmodium falciparum and the hepatic quiescent forms of P. vivax. Yet its mechanism of action is still poorly understood. In this study, we used the yeast Saccharomyces cerevisiae model to help uncover the mode of action of primaquine. We found that the growth inhibitory effect of primaquine was restricted to cells that relied on respiratory function to proliferate and that deletion of SOD2 encoding the mitochondrial superoxide dismutase severely increased its effect, which can be countered by the overexpression of AIM32 and MCR1 encoding mitochondrial enzymes involved in the response to oxidative stress. This indicated that ROS produced by respiratory activity had a key role in primaquine-induced growth defect. We observed that Δsod2 cells treated with primaquine displayed a severely decreased activity of aconitase that contains a Fe–S cluster notoriously sensitive to oxidative damage. We also showed that in vitro exposure to primaquine impaired the activity of purified aconitase and accelerated the turnover of the Fe–S cluster of the essential protein Rli1. It is suggested that ROS-labile Fe–S groups are the primary targets of primaquine. Aconitase activity is known to be essential at certain life-cycle stages of the malaria parasite. Thus primaquine-induced damage of its labile Fe–S cluster – and of other ROS-sensitive enzymes – could inhibit parasite development.

Mitochondrial Ferredoxin Determines Vulnerability of Cells to Copper Excess

“…In contrast to the observed rescue of Cu sensitivity via overexpression of Yah1 ( Figures 1 B and 1C) or of pro-oxidant action via Rli1 ( Alhebshi et al., 2012 , Laleve et al., 2016 , Vallieres and Avery, 2017 ), increased expression of nonessential FeS proteins is known potentially to exacerbate ROS stress. This is because of the increased pool of labile FeS which, following turnover (e.g., ROS mediated), leads to the accumulation of free Fe and further potential for ROS stress via Fe-catalyzed Fenton chemistry ( Keyer and Imlay, 1996 , Liochev and Fridovich, 1999 ).…”

The Candidate Antimalarial Drug MMV665909 Causes Oxygen-Dependent mRNA Mistranslation and Synergizes with Quinoline-Derived Antimalarials

“…A similar strategy would probably apply to MMV665909, given the action on fidelity of protein synthesis described here. The current antimalarials amodiaquine, chloroquine, and primaquine are all reported to promote oxidative stress ( 18 , 57 – 59 ) in common, we argue, with MMV665909 ( Fig. 2 and 3 ).…”

“…Among the essential proteins involved in translation termination, function of the iron-sulfur (FeS) protein Rli1 (ABCE1 in human and other organisms) is known to be oxygen sensitive. Rli1 function is an important target of reactive oxygen species (ROS) and ROS-generating chemicals ( 34 ), including the antimalarial primaquine (PMQ) ( 18 ). In translation termination, Rli1 in concert with Sup45 (eukaryotic release factor 1 [eRF1]), dissociates and splits the ribosome into its subunits ( 35 ) ( Fig.…”

“…Sequence identity with the yeast Rli1 protein is 59% in the human pathogen P. falciparum (the PF3D7_1368200 gene). As indicated above, Rli1 function has been shown to be a primary cellular target of ROS and redox-active agents such as H 2 O 2 , paraquat, copper ( 34 ), and primaquine ( 18 ). Decreased Rli1 activity is known to result in stop codon readthrough ( 37 ), similar to the effect of MMV665909.…”

“…2 and 3 ). ROS-labile FeS groups have been described as the primary targets of PMQ ( 18 ). An increase of oxidized proteins was observed in parasites treated with CQ ( 58 ).…”