PfGCN5, a global regulator of stress responsive genes, modulates artemisinin resistance inPlasmodium falciparum

Abstract

2 3 4 PfGCN5, a global regulator of stress responsive genes, modulates artemisinin resistance 5 in Plasmodium falciparum 2 25 Abstract26 Plasmodium falciparum has evolved resistance to almost all front-line drugs including 27 artemisinins, which threatens malaria control and elimination strategies. Oxidative stress and 28 protein damage responses have emerged as key players in the generation of artemisinin 29 resistance. In this study, we show that PfGCN5, a histone acetyltransferase, binds to the stress 30 responsive and multi-variant family genes in poised state and regulates their expression under 31 stress conditions. We have also provided biochemical and cellular evidences that PfGCN5 32 regulates stress responsive genes by acetylation of PfAlba3. Furthermore, we show that upon 33 artemisinin exposure, genome-wide binding sites for PfGCN5 are increased and it is directly 34 associated with the genes implicated in artemisinin resistance generation like BiP and TRiC 35 chaperone. Moreover, inhibition of PfGCN5 in artemisinin resistant parasites, Kelch13 36 mutant, K13I543T and K13C580Y (RSA~ 25% and 6%, respectively) reverses the sensitivity 37 of the parasites to artemisinin treatment indicating its role in drug resistance generation.38 Together, these findings elucidate the role of PfGCN5 as a global chromatin regulator of 39 stress-responses with potential role in modulating artemisinin drug resistance, and identify 40 PfGCN5 as an important target against artemisinin resistant parasites. 41 3 42 Author Summary 43 Malaria parasites are constantly adapting to the drugs we used to eliminate them. Thus, when 44 we use the drugs to kill parasites; with time, we select the parasites with the favourable 45 genetic changes. Parasites develop various strategies to overcome exposure to the drugs by 46 exhibiting the stress responses. The changes specific to the drug adapted parasites can be 47 used to understand the mechanism of drug resistance generation. In this study, we have 48 identified PfGCN5 as a global transcriptional regulator of stress responses in Plasmodium 49 falciparum. Inhibition of PfGCN5 reverses the sensitivity of the parasites to the artemisinin 50 drug and identify PfGCN5 as an important target against artemisinin resistant parasites. 51 52 53 54 55 56 57 58 59 4 60 Introduction 61 Malaria is a life threatening infectious disease caused by parasites from the genus 62 Plasmodium, with an estimated 200 million cases worldwide [1]. The Anopheles mosquito 63 serves as a vector for varied species of the human malaria parasite namely P. falciparum, P. 64 vivax, P. ovale, P. malariae and P. knowlesi. Of these five species, P. falciparum causes most 65 lethal form of malaria. The Plasmodium life cycle consists of two phases, sexual and asexual 66 in mosquitoes and humans, respectively. Since Plasmodium completes its life cycle in two 67 different hosts, it requires mechanisms for coordinated modulation of gene expression [2]. An 68 efficient transcriptional and post-transcriptional regulation of gene ex...