A chemical susceptibility profile of thePlasmodium falciparumtransmission stages by complementary cell-based gametocyte assays

Abstract

This work indicates that the luciferase and gametocyte LDH assays are interchangeable and that their specific advantages can be exploited to design an HTS pipeline leading to new transmission-blocking compounds. Results from these assays consistently defined a gametocyte chemical susceptibility profile, relevant to the planning of future drug discovery strategies.

The need to compare: assessing the level of agreement of three high-throughput assays against Plasmodium falciparum mature gametocytes

“…Their results, which were based on % inhibition only and thus did not allow to compare threshold effects or potency, indicated that the compounds tested had a lower activity in the pLDH and ATP assays in comparison to the luciferase and resazurin assays. The second report, by D’Alessandro et al ., compared recently established luciferase and pLDH assays against early and late stage gametocytes in dose-response at a fixed incubation time of 72 h25. This study showed an excellent agreement between the two assays, which measure different biomarkers.…”

“…These include the use of the metabolic indicator AlamarBlue18, parasite lactate dehydrogenase (pLDH)19, ATP production2021, expression of reporter genes in transgenic parasites lines22232425, fluorescent staining of gametocytes26, fluorescent staining of female gametes27, detection of female gamete specific antigens282930 and time-course imaging of exflagellating male gametocytes28.…”

A high susceptibility to redox imbalance of the transmissible stages of Plasmodium falciparum revealed with a luciferase‐based mature gametocyte assay

“…Dose-response curves on parasites exposed to MB for 24, 48 and 72h were readily obtained with an excellent assay Z′ factor (Zhang et al , 1999) of 0.88, confirming the potency of MB in killing mature gametocytes and showing that this increased with the time of drug exposure (Fig 3B). Importantly, the assay was able to detect MB gametocytocidal activity after only 24h of drug exposure, which is rarely observed in cell-based assays on stage V gametocytes even after treatment with potent gametocytocidal compounds such as epoxomicin (D’Alessandro et al , 2016). …”

Discovering New Transmission-Blocking Antimalarial Compounds: Challenges and Opportunities

“…Assays to measure the killing of metabolically hypo-active gametocytes are challenging but different groups have developed several platforms (e.g. [14,19,20,23,27,31,34,[36][37][38][39][40]). In A primary screen is performed using an assay platform (e.g.…”

“…In A primary screen is performed using an assay platform (e.g. colorimetric [19,37], enzymatic, based on stage-specific reporters [36,38] or high-content imaging [20,23]), which is amenable to (medium-)/high-throughput screening (MTS/HTS). To date, no difference has been seen in activity of compounds tested against wild-type or transgenic parasite lines [36] although different genetic backgrounds should always be taken into consideration in the interpretation of results.…”