Sulfonylpiperazine compounds prevent Plasmodium falciparum invasion of red blood cells through interference with actin-1/profilin dynamics

Abstract

With emerging resistance to frontline treatments, it is vital that new antimalarial drugs are identified to target Plasmodium falciparum. We have recently described a compound, MMV020291, as a specific inhibitor of red blood cell (RBC) invasion, and have generated analogues with improved potency. Here, we generated resistance to MMV020291 and performed whole genome sequencing of 3 MMV020291-resistant populations. This revealed 3 nonsynonymous single nucleotide polymorphisms in 2 genes; 2 in profilin (N154Y, K124N) and a third one in actin-1 (M356L). Using CRISPR-Cas9, we engineered these mutations into wild-type parasites, which rendered them resistant to MMV020291. We demonstrate that MMV020291 reduces actin polymerisation that is required by the merozoite stage parasites to invade RBCs. Additionally, the series inhibits the actin-1-dependent process of apicoplast segregation, leading to a delayed death phenotype. In vitro cosedimentation experiments using recombinant P. falciparum proteins indicate that potent MMV020291 analogues disrupt the formation of filamentous actin in the presence of profilin. Altogether, this study identifies the first compound series interfering with the actin-1/profilin interaction in P. falciparum and paves the way for future antimalarial development against the highly dynamic process of actin polymerisation.

Aryl amino acetamides prevent the development ofPlasmodium falciparumrings via inhibition of the lipid transfer protein PfSTART1

“…Growth assays demonstrated the resistance against M-833 was heritable, with a 17-fold increase in EC50 compared to 3D7 parasites (Fig 1B). To identify the target of M-833, genomic DNA was extracted from the clonal lines of PopD and PopE and subjected to whole genome sequencing using MinION technology and compared to clonal 3D7 parental parasites (Dans et al, 2023). This identified 14 non-synonymous single nucleotide polymorphisms (SNP) across nine different genes when compared to the 3D7 parental strain (Table S1).…”

“…Two hits (MMV020291 and MMV006833) displayed promising traits for invasion inhibition (Dans et al, 2020). Recently we described the mode of action of MMV020291, finding that it targeted parasite actin-profilin interactions and prevented merozoites from penetrating the RBC (Dans et al, 2023). In contrast, compound MMV006833 (M-833) had a novel effect whereby the merozoite entered its target RBC but failed to differentiate into an amoeboid ring-stage parasite during the formation of the parasitophorous vacuole membrane (PVM) around the parasite (Dans et al, 2020).…”

A Pyridyl-Furan Series Developed from the Open Global Health Library Block Red Blood Cell Invasion and Protein Trafficking in Plasmodium falciparum through Potential Inhibition of the Parasite’s PI4KIIIB Enzyme

“…15,16 Novel targets identified by these screens include actin and profilin, essential components of the invasion machinery used by the parasite to enter RBCs. 17 Egress and invasion inhibitors could be particularly effective compounds since reducing the capacity of invasive merozoite stage parasites to rapidly invade RBCs would leave the merozoites exposed to host immune clearance. 18,19 While phenotypic screens for egress and invasion can yield novel targets such as actin and profilin, they are not guaranteed to return solely novel targets.…”

“…While phenotypic screens for egress and invasion can yield novel targets such as actin and profilin, they are not guaranteed to return solely novel targets . Indeed, nearly half of the egress and invasion inhibitors identified in recent screens of the MMV Malaria and Pathogen Boxes were also flagged as inhibitors of PfATP4. ,,, These have later been determined to be specific inhibitors of egress and not invasion and serve to dysregulate sodium ion levels and cellular pH, explaining why late schizont-stage parasites are particularly susceptible to the effects of PfATP4 inhibitors. , Therefore, while egress and invasion screens can also identify inhibitors to well-studied targets, they can also add important additional biological information about the function of targets.…”

“…Another way of finding and prioritizing inhibitors with novel MoAs is to perform phenotypic screens for the inhibition of biological phenomena such as egress from old red blood cells (RBCs) and invasion of new RBCs. Such screens of the Medicines for Malaria Venture (MMV) Malaria and Pathogen boxes have identified dozens of compounds that inhibit egress and invasion. , Novel targets identified by these screens include actin and profilin, essential components of the invasion machinery used by the parasite to enter RBCs . Egress and invasion inhibitors could be particularly effective compounds since reducing the capacity of invasive merozoite stage parasites to rapidly invade RBCs would leave the merozoites exposed to host immune clearance. , …”