@article {44494,
	title = {Targeted phenotypic screening in plasmodium falciparum and toxoplasma gondii reveals novel modes of action of medicines for malaria venture malaria box molecules},
	journal = {mSphere},
	volume = {3},
	year = {2018},
	month = {JAN},
	pages = { e00534-17},
	type = {Journal Article},
	abstract = {The Malaria Box collection includes 400 chemically diverse small molecules with documented potency against malaria parasite growth, but the underlying modes of action are largely unknown. Using complementary phenotypic screens against Plasmodium falciparum and Toxoplasma gondii, we report phenotype-specific hits based on inhibition of overall parasite growth, apicoplast segregation, and egress or host invasion, providing hitherto unavailable insights into the possible mechanisms affected. First, the Malaria Box library was screened against tachyzoite stage T. gondii and the half-maximal effective concentrations (EC50s) of molecules showing >=80\% growth inhibition at 10 {\textmu}M were determined. Comparison of the EC50s for T. gondii and P. falciparum identified a subset of 24 molecules with nanomolar potency against both parasites. Thirty molecules that failed to induce acute growth inhibition in T. gondii tachyzoites in a 2-day assay caused delayed parasite death upon extended exposure, with at least three molecules interfering with apicoplast segregation during daughter cell formation. Using flow cytometry and microscopy-based examinations, we prioritized 26 molecules with the potential to inhibit host cell egress/invasion during asexual developmental stages of P. falciparum. None of the inhibitors affected digestive vacuole integrity, ruling out a mechanism mediated by broadly specific protease inhibitor activity. Interestingly, five of the plasmodial egress inhibitors inhibited ionophore-induced egress of T. gondii tachyzoites. These findings highlight the advantage of comparative and targeted phenotypic screens in related species as a means to identify lead molecules with a conserved mode of action. Further work on target identification and mechanism analysis will facilitate the development of antiparasitic compounds with cross-species efficacy.},
	issn = {23795042},
	doi = {10.1128/mSphere.00534-17},
	author = {Subramanian, Gowtham},
	editor = {Belekar, Meenakshi A.}
}
@article {46175,
	title = {Targeted phenotypic screening in plasmodium falciparum and toxoplasma gondii reveals novel modes of action of medicines for malaria venture malaria box molecules (vol 3, e00534-17, 2018)},
	journal = {MSphere},
	volume = {4},
	year = {2019},
	month = {APR},
	pages = {e00159-19},
	type = {Correction},
	issn = {2379-5042},
	doi = {10.1128/mSphere.00159-19},
	author = {Subramanian, Gowtham and Belekar, Meenakshi A. and Shukla, Anurag and Tong, Jie Xin and Sinha, Ameya and Chu, Trang T. T. and Kulkarni, Akshay S. and Preiser, Peter R. and Reddy, D. Srinivasa and Tan, Kevin S. W. and Shanmugam, Dhanasekaran and Chandramohanadas, Rajesh}
}
@article {46878,
	title = {Whole-cell phenotypic screening of medicines for malaria venture pathogen box identifies specific inhibitors of plasmodium falciparum late-stage development and egress},
	journal = {Antimicrobial Agents and Chemotherapy},
	volume = {64},
	year = {2020},
	month = {MAY},
	pages = {e01802-19},
	type = {Article},
	abstract = {<p>We report a systematic, cellular phenotype-based antimalarial screening of the Medicines for Malaria Venture Pathogen Box collection, which facilitated the identification of specific blockers of late-stage intraerythrocytic development of Plasmodium falciparum. First, from standard growth inhibition assays, we identified 173 molecules with antimalarial activity (50\% effective concentration [EC50] \&lt;= 10 mu M), which included 62 additional molecules over previously known antimalarial candidates from the Pathogen Box. We identified 90 molecules with EC50 of \&lt;= 1 mu M, which had significant effect on the ring-trophozoite transition, while 9 molecules inhibited the trophozoite-schizont transition and 21 molecules inhibited the schizontring transition (with \&gt;= 50\% parasites failing to proceed to the next stage) at 1 mu M. We therefore rescreened all 173 molecules and validated hits in microscopy to prioritize 12 hits as selective blockers of the schizont-ring transition. Seven of these molecules inhibited the calcium ionophore-induced egress of Toxoplasma gondii, a related apicomplexan parasite, suggesting that the inhibitors may be acting via a conserved mechanism which could be further exploited for target identification studies. We demonstrate that two molecules, MMV020670 and MMV026356, identified as schizont inhibitors in our screens, induce the fragmentation of DNA in merozoites, thereby impairing their ability to egress and invade. Further mechanistic studies would facilitate the therapeutic exploitation of these molecules as broadly active inhibitors targeting late-stage development and egress of apicomplexan parasites relevant to human health.</p>
},
	keywords = {DNA fragmentation, egress, Medicines for Malaria Venture, MMV, Pathogen Box, phenotypic screening, Plasmodium falciparum, schizonts, stage-specific inhibition},
	issn = {0066-4804},
	doi = {10.1128/AAC.01802-19},
	author = {Patra, Alok Tanala and Hingamire, Tejashri and Belekar, Meenakshi A. and Xiong, Aoli and Subramanian, Gowtham and Bozdech, Zbynek and Preiser, Peter and Shanmugam, Dhanasekaran and Chandramohanadas, Rajesh}
}
