Chemoproteomics validates selective targeting of Plasmodium M1 alanyl aminopeptidase as an antimalarial strategy

TL;DR

Scientists validated a new antimalarial drug target by showing that a selective inhibitor effectively targets a specific malaria parasite enzyme without harming human cells.

Contribution

The study provides multi-omic validation of Plasmodium M1 alanyl aminopeptidase as a selective antimalarial drug target using the inhibitor MIPS2673.

Findings

MIPS2673 selectively inhibits Plasmodium M1 aminopeptidases with no host cytotoxicity.

Chemoproteomic methods confirmed PfA-M1 as the sole target of MIPS2673 in parasites.

Metabolomics showed MIPS2673 inhibits PfA-M1's role in hemoglobin digestion.

Abstract

New antimalarial drug candidates that act via novel mechanisms are urgently needed to combat malaria drug resistance. Here, we describe the multi-omic chemical validation of
Plasmodium
M1 alanyl metalloaminopeptidase as an attractive drug target using the selective inhibitor, MIPS2673. MIPS2673 demonstrated potent inhibition of recombinant
Plasmodium falciparum
(
Pf
A-M1) and
Plasmodium vivax
(
Pv
A-M1) M1 metalloaminopeptidases, with selectivity over other
Plasmodium
and human aminopeptidases, and displayed excellent
in vitro
antimalarial activity with no significant host cytotoxicity. Orthogonal label-free chemoproteomic methods based on thermal stability and limited proteolysis of whole parasite lysates revealed that MIPS2673 solely targets
Pf
A-M1 in parasites, with limited proteolysis also enabling estimation of the binding site on
Pf
A-M1 to within ~5 Å of that determined by X-ray crystallography. Finally, functional investigation by untargeted metabolomics demonstrated that MIPS2673 inhibits the key role of
Pf
A-M1 in haemoglobin digestion. Combined, our unbiased multi-omic target deconvolution methods confirmed the on-target activity of MIPS2673, and validated selective inhibition of M1 alanyl metalloaminopeptidase as a promising antimalarial strategy.