Use of a Selective Inhibitor To Define the Chemotherapeutic Potential of the Plasmodial Hexose Transporter in Different Stages of the Parasite's Life Cycle

Slavic, Ksenija; Delves, Michael J.; Prudêncio, Miguel; Talman, Arthur M.; Straschil, Ursula; Derbyshire, Elvira T.; Xu, Zhengyao; Sinden, Robert E.; Mota, Maria M.; Morin, Christophe; Tewari, Rita; Krishna, Sanjeev; Staines, Henry M.

doi:10.1128/aac.01739-10

Cited by 41 publications

(45 citation statements)

References 34 publications

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“…berghei gametogenesis was sex-specific since female (macro) gametes emerged from the red blood cells in the presence of 2DG (Fig 5C). Moreover, as seen when the hexose transporter was inhibited [31], pre-incubation of gametocytes with 2DG had a greater inhibitory effect on conversion to ookinetes than if the reagent was added after activation (Fig 5E). This sex-specific effect of 2DG can be exploited to produce populations of fertile activated female gametes for either further analysis or genetic crossing experiments and demonstrates that male gametogenesis (but not female gametogenesis) is reliant on glycolysis.…”

Section: Resultsmentioning

confidence: 78%

“…berghei . Glycolysis is required for microgamete motility [30] and the Plasmodium hexose transporter is essential for both asexual blood stage growth and microgametogenesis [31,32]. Disruption of mitochondrial α-ketoglutarate dehydrogenase in P .…”

Section: Resultsmentioning

confidence: 99%

“…Upon activation, the male gametocyte initiates three rounds of energy intensive rapid nuclear replication and packages the resulting nuclei into eight male gametes [42,43]. Our labelling experiments demonstrated that these motile parasite stages exhibit high rates of glycolysis which are likely to be the major source of ATP for male microgamete motility [30,31] and exflagellation. Inhibition of glycolysis with 2DG prevented exflagellation and microgametogenesis, but did not affect female gamete maturation.…”

Section: Discussionmentioning

confidence: 99%

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Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments

et al. 2016

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Malaria parasites (Plasmodium spp.) encounter markedly different (nutritional) environments during their complex life cycles in the mosquito and human hosts. Adaptation to these different host niches is associated with a dramatic rewiring of metabolism, from a highly glycolytic metabolism in the asexual blood stages to increased dependence on tricarboxylic acid (TCA) metabolism in mosquito stages. Here we have used stable isotope labelling, targeted metabolomics and reverse genetics to map stage-specific changes in Plasmodium berghei carbon metabolism and determine the functional significance of these changes on parasite survival in the blood and mosquito stages. We show that glutamine serves as the predominant input into TCA metabolism in both asexual and sexual blood stages and is important for complete male gametogenesis. Glutamine catabolism, as well as key reactions in intermediary metabolism and CoA synthesis are also essential for ookinete to oocyst transition in the mosquito. These data extend our knowledge of Plasmodium metabolism and point towards possible targets for transmission-blocking intervention strategies. Furthermore, they highlight significant metabolic differences between Plasmodium species which are not easily anticipated based on genomics or transcriptomics studies and underline the importance of integration of metabolomics data with other platforms in order to better inform drug discovery and design.

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments

et al. 2016

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“…This is supported by the ability of compound 3361, a glucose analogue that inhibits PfHT with high selectivity over the human orthologue GLUT1, to inhibit asexual intraerythrocytic growth in culture (9). Compound 3361 is also active against Plasmodium berghei liver and transmission stage parasites in infected mice (10), suggesting that PfHT is a promising target for full life cycle activity. However, while compound 3361 validates efforts to target PfHT, this compound is not itself considered drug-like and is therefore not a valid candidate for lead development (11).…”

mentioning

confidence: 68%

A Novel Fluorescence Resonance Energy Transfer-Based Screen in High-Throughput Format To Identify Inhibitors of Malarial and Human Glucose Transporters

Kraft

Heitmeier

Putanko

et al. 2016

Antimicrob Agents Chemother

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The glucose transporter PfHT is essential to the survival of the malaria parasite Plasmodium falciparum and has been shown to be a druggable target with high potential for pharmacological intervention. Identification of compounds against novel drug targets is crucial to combating resistance against current therapeutics. Here, we describe the development of a cell-based assay system readily adaptable to high-throughput screening that directly measures compound effects on PfHT-mediated glucose transport. Intracellular glucose concentrations are detected using a genetically encoded fluorescence resonance energy transfer (FRET)-based glucose sensor. This allows assessment of the ability of small molecules to inhibit glucose uptake with high accuracy (Z= factor of >0.8), thereby eliminating the need for radiolabeled substrates. Furthermore, we have adapted this assay to counterscreen PfHT hits against the human orthologues GLUT1, -2, -3, and -4. We report the identification of several hits after screening the Medicines for Malaria Venture (MMV) Malaria Box, a library of 400 compounds known to inhibit erythrocytic development of P. falciparum. Hit compounds were characterized by determining the half-maximal inhibitory concentration (IC 50 ) for the uptake of radiolabeled glucose into isolated P. falciparum parasites. One of our hits, compound MMV009085, shows high potency and orthologue selectivity, thereby successfully validating our assay for antimalarial screening. Malaria is a major threat to the human population in large areas of the world, affecting over 200 million people per year (1, 2). Beyond the effects of this disease on human life, malaria also cripples economic development and burdens the health care systems of countries where malaria is endemic (3). The emergence of parasites with resistance to even the most potent existing antimalarial drugs, such as the artemisinins (4), has made paramount the development of novel drugs that target essential pathways for parasite survival. Blood stage parasites utilize glucose for both biomass production and ATP synthesis (5). The malarial hexose transporter, Plasmodium falciparum hexose transporter (PfHT), first cloned by Woodrow et al. in 1999 (6), mediates parasite transport of glucose, fructose, mannose, and galactose (7). Since PfHT is essential for parasite survival (8), this protein is a highly promising molecular target for antimalarial drug development. This is supported by the ability of compound 3361, a glucose analogue that inhibits PfHT with high selectivity over the human orthologue GLUT1, to inhibit asexual intraerythrocytic growth in culture (9). Compound 3361 is also active against Plasmodium berghei liver and transmission stage parasites in infected mice (10), suggesting that PfHT is a promising target for full life cycle activity. However, while compound 3361 validates efforts to target PfHT, this compound is not itself considered drug-like and is therefore not a valid candidate for lead development (11). We have recently extended these earlier find...

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“…Because PfHT inhibition retards both the liver and mosquito stage development of rodent malaria parasites (43), novel PfHT inhibitors hold great promise for use in malaria treatment and as transmission-blocking agents. The existing pharmacokinetic and safety data for lopinavir should allow rapid assessment of the suitability and efficacy of this agent in non-HIV-infected patient populations.…”

Section: Discussionmentioning

confidence: 99%

The Glucose Transporter PfHT1 Is an Antimalarial Target of the HIV Protease Inhibitor Lopinavir

Kraft

Armstrong

Heitmeier

et al. 2015

Antimicrob Agents Chemother

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Malaria and HIV infection are coendemic in a large portion of the world and remain a major cause of morbidity and mortality. Growing resistance of Plasmodium species to existing therapies has increased the need for new therapeutic approaches. The Plasmodium glucose transporter PfHT is known to be essential for parasite growth and survival. We have previously shown that HIV protease inhibitors (PIs) act as antagonists of mammalian glucose transporters. While the PI lopinavir is known to have antimalarial activity, the mechanism of action is unknown. We report here that lopinavir blocks glucose uptake into isolated malaria parasites at therapeutically relevant drug levels. Malaria parasites depend on a constant supply of glucose as their primary source of energy, and decreasing the available concentration of glucose leads to parasite death. We identified the malarial glucose transporter PfHT as a target for inhibition by lopinavir that leads to parasite death. This discovery provides a mechanistic basis for the antimalarial effect of lopinavir and provides a direct target for novel drug design with utility beyond the HIV-infected population.

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Use of a Selective Inhibitor To Define the Chemotherapeutic Potential of the Plasmodial Hexose Transporter in Different Stages of the Parasite's Life Cycle

Cited by 41 publications

References 34 publications

Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments

Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments

A Novel Fluorescence Resonance Energy Transfer-Based Screen in High-Throughput Format To Identify Inhibitors of Malarial and Human Glucose Transporters

The Glucose Transporter PfHT1 Is an Antimalarial Target of the HIV Protease Inhibitor Lopinavir

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