Fig. 6: PfSTART1 inhibitors block ring development but their effect is reversible.
A, B Tightly synchronised Hyp1-Nluc schizonts were exposed to the following drugs for 4 h (during the egress/invasion window): M-833 (2 µM), W-991 (60 nM), DMSO (0.02%), ML10 (30 nM) (egress inhibitor), E64 (10 µM) (irreversible egress inhibitor), and heparin (100 µg/mL) (invasion inhibitor). After 4 h, non-egressed schizonts were eliminated with a sorbitol treatment, the drugs washed off, and parasites were followed over 72 h. Smears were taken at each timepoint (A) and growth was assessed with a bioluminescence read-out in relative light units (RLU x 105) (B). n = 3 biological replicates, mean +/− SD. Ordinary one-way ANOVA with Tukey’s multiple comparison test was conducted on the 72 h timepoint. *p < 0.05 (ML10 vs. Heparin; not shown on the graph, p = 0.0484). ***p < 0.005 (DMSO vs. ML10, p = 0.0006; DMSO vs. E64, p = 0.0002). ****p < 0.0001 (DMSO vs. M-833, W-991 and heparin). Highly synchronous ring-stage 3D7 parasites were exposed to M-833 (2 µM), W-991 (60 nM) or DMSO (0.02%). After 48 h, populations of M-833 and W-991-treated parasites were treated with sorbitol, compounds were washed out (w/o) (dotted lines), and morphology visualised by Giemsa-stained thin blood smears (C) and parasitemia was quantified by SYBR Green staining and flow cytometry (D) every 48 h for four following cycles of growth. Error bars indicate the standard deviation of two biological replicates, each made up of three technical replicates. Source data are provided as a Source Data file.
