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Identification of inhibitors of Plasmodium falciparum gametocyte development.

Duffy S, Avery VM - Malar. J. (2013)

Bottom Line: Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria.The comprehensive profiling of in vitro activity of anti-malarial compounds against both early (I-III) and late (IV-V) stage P. falciparum gametocytes, along with the high throughput screening (HTS) outcomes from the MMV malaria box are described.IC50 values were obtained for 36 current anti-malarial compounds for activities against asexual, early and late stage gametocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland 4111, Australia. v.avery@griffith.edu.au.

ABSTRACT

Background: Plasmodium falciparum gametocytes, specifically mature stages, are the only stage in man transmissible to the mosquito vector responsible for malaria transmission. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria. The comprehensive profiling of in vitro activity of anti-malarial compounds against both early (I-III) and late (IV-V) stage P. falciparum gametocytes, along with the high throughput screening (HTS) outcomes from the MMV malaria box are described.

Method: Two anti-gametocyte HTS assays based on confocal fluorescence microscopy, utilizing both a gametocyte specific protein (pfs16-Luc-GFP) and a viability marker (MitoTracker Red CM-H2XRos) (MTR), were used for the measurement of anti-gametocytocidal activity. This combination provided a direct observation of gametocyte number per assay well, whilst defining the viability of each gametocyte imaged.

Results: IC50 values were obtained for 36 current anti-malarial compounds for activities against asexual, early and late stage gametocytes. The MMV malaria box was screened and actives progressed for IC50 evaluation. Seven % of the "drug-like" and 21% of the "probe-like" compounds from the MMV malaria box demonstrated equivalent activity against both asexual and late stage gametocytes.

Conclusions: The assays described were shown to selectively identify compounds with gametocytocidal activity and have been demonstrated suitable for HTS with the capability of screening in the order of 20,000 compounds per screening campaign, two to three times per seven-day week.

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Compound activity distribution against early (I-III) and late (IV-V) stage gametocytes. Normal distribution of the activity of MMV malaria box compounds against the early (A) and late (B) stage gametocytes was not observed as the compound set has an asexual bias.
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Figure 2: Compound activity distribution against early (I-III) and late (IV-V) stage gametocytes. Normal distribution of the activity of MMV malaria box compounds against the early (A) and late (B) stage gametocytes was not observed as the compound set has an asexual bias.

Mentions: Duplicate point screening at 5 μM and 0.5 μM doses was performed for the MMV malaria box prepared as described above, on both the early and late stage gametocyte assays. The activity distribution generated for both assays (Figures 2A and B) did not produce a normal distribution; however this was expected due to the library being primarily comprised of compounds with demonstrated asexual anti-malarial activity. It is noted that due to the use of relative % inhibition in relation to 5 μM puromycin some compounds demonstrate a value greater than 100% inhibition. A number of parameters can cause this, including compound related effects such as lysis of all RBCs, specific lysis of iRBCs, or compound fluorescence quenching of the GFP or MTR signal.


Identification of inhibitors of Plasmodium falciparum gametocyte development.

Duffy S, Avery VM - Malar. J. (2013)

Compound activity distribution against early (I-III) and late (IV-V) stage gametocytes. Normal distribution of the activity of MMV malaria box compounds against the early (A) and late (B) stage gametocytes was not observed as the compound set has an asexual bias.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3842684&req=5

Figure 2: Compound activity distribution against early (I-III) and late (IV-V) stage gametocytes. Normal distribution of the activity of MMV malaria box compounds against the early (A) and late (B) stage gametocytes was not observed as the compound set has an asexual bias.
Mentions: Duplicate point screening at 5 μM and 0.5 μM doses was performed for the MMV malaria box prepared as described above, on both the early and late stage gametocyte assays. The activity distribution generated for both assays (Figures 2A and B) did not produce a normal distribution; however this was expected due to the library being primarily comprised of compounds with demonstrated asexual anti-malarial activity. It is noted that due to the use of relative % inhibition in relation to 5 μM puromycin some compounds demonstrate a value greater than 100% inhibition. A number of parameters can cause this, including compound related effects such as lysis of all RBCs, specific lysis of iRBCs, or compound fluorescence quenching of the GFP or MTR signal.

Bottom Line: Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria.The comprehensive profiling of in vitro activity of anti-malarial compounds against both early (I-III) and late (IV-V) stage P. falciparum gametocytes, along with the high throughput screening (HTS) outcomes from the MMV malaria box are described.IC50 values were obtained for 36 current anti-malarial compounds for activities against asexual, early and late stage gametocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland 4111, Australia. v.avery@griffith.edu.au.

ABSTRACT

Background: Plasmodium falciparum gametocytes, specifically mature stages, are the only stage in man transmissible to the mosquito vector responsible for malaria transmission. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria. The comprehensive profiling of in vitro activity of anti-malarial compounds against both early (I-III) and late (IV-V) stage P. falciparum gametocytes, along with the high throughput screening (HTS) outcomes from the MMV malaria box are described.

Method: Two anti-gametocyte HTS assays based on confocal fluorescence microscopy, utilizing both a gametocyte specific protein (pfs16-Luc-GFP) and a viability marker (MitoTracker Red CM-H2XRos) (MTR), were used for the measurement of anti-gametocytocidal activity. This combination provided a direct observation of gametocyte number per assay well, whilst defining the viability of each gametocyte imaged.

Results: IC50 values were obtained for 36 current anti-malarial compounds for activities against asexual, early and late stage gametocytes. The MMV malaria box was screened and actives progressed for IC50 evaluation. Seven % of the "drug-like" and 21% of the "probe-like" compounds from the MMV malaria box demonstrated equivalent activity against both asexual and late stage gametocytes.

Conclusions: The assays described were shown to selectively identify compounds with gametocytocidal activity and have been demonstrated suitable for HTS with the capability of screening in the order of 20,000 compounds per screening campaign, two to three times per seven-day week.

Show MeSH
Related in: MedlinePlus