Disrupting Plasmodium UIS3–host LC3 interaction with a small molecule causes parasite elimination from host cells

Abstract

The malaria parasite Plasmodium obligatorily infects and replicates inside hepatocytes surrounded by a parasitophorous vacuole membrane (PVM), which is decorated by the host-cell derived autophagy protein LC3. We have previously shown that the parasite-derived, PVM-resident protein UIS3 sequesters LC3 to avoid parasite elimination by autophagy from hepatocytes. Here we show that a small molecule capable of disrupting this interaction triggers parasite elimination in a host cell autophagy-dependent manner. Molecular docking analysis of more than 20 million compounds combined with a phenotypic screen identified one molecule, C4 (4-{[4-(4-{5-[3-(trifluoromethyl) phenyl]-1,2,4-oxadiazol-3-yl}benzyl)piperazino]carbonyl}benzonitrile), capable of impairing infection. Using biophysical assays, we established that this impairment is due to the ability of C4 to disrupt UIS3–LC3 interaction, thus inhibiting the parasite’s ability to evade the host autophagy response. C4 impacts infection in autophagy-sufficient cells without harming the normal autophagy pathway of the host cell. This study, by revealing the disruption of a critical host–parasite interaction without affecting the host’s normal function, uncovers an efficient anti-malarial strategy to prevent this deadly disease.

Plasmodium parasitophorous vacuole membrane-resident protein UIS4 manipulates host cell actin to avoid parasite elimination

“…However, the functional role of these proteins is only now starting to be unveiled. We have recently shown that Plasmodium UIS3 sequesters host LC3 to avoid elimination by autophagy in hepatocytes ( Real et al., 2017 ) and that disruption of that interaction by a small molecule causes parasite elimination from host cells ( Setua et al., 2020 ). We now show that Plasmodium parasites have devised a different way to avoid elimination by a distinct host-cell-intrinsic mechanism.…”

Targeting the Mitochondria-Proteostasis Axis to Delay Aging

“…Recently, small molecules have been developed that can promote the interaction of LC3 with specific target proteins, e.g., the Huntington’s disease-associated PolyQ protein huntingtin to mediate their autophagic degradation ( Li et al, 2019 ). This strategy also works in the other direction, as demonstrated for a recently discovered small molecule that can disrupt the interaction of the malaria parasite factor UIS3 with LC3 ( Setua et al, 2020 ). This modulation of interaction of specific target proteins with the autophagic machinery is an exciting therapeutic avenue, and more so as an increasing number of proteins has been shown to form aggregates during aging, which in turn may drive other proteotoxic events such as amyloid beta aggregation ( Groh et al, 2017 ).…”

Active APPL1 sequestration by Plasmodium favors liver-stage development

“…Pbrab5b-HA fragment was released from pJet1.2 backbone through digestion with HindIII (New England Biolabs, Massachusetts, USA) and NotI (New England Biolabs), as per manufacturer's instructions. The Plasmodium expression vector (PEV) (Setua et al, 2020) was also digested with HindIII and NotI. The digests were resolved on 1% agarose gel and the band corresponding to Pbrab5b-HA (1.3 kb) and the linearized PEV (4.9 kb) were excised and purified using the QIAquick Gel Extraction Kit (Qiagen).…”