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Deconvoluting heme biosynthesis to target blood-stage malaria parasites.

Sigala PA, Crowley JR, Henderson JP, Goldberg DE - Elife (2015)

Bottom Line: Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX).We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen.This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology, Washington University School of Medicine, St Louis, United States.

ABSTRACT
Heme metabolism is central to blood-stage infection by the malaria parasite Plasmodium falciparum. Parasites retain a heme biosynthesis pathway but do not require its activity during infection of heme-rich erythrocytes, where they can scavenge host heme to meet metabolic needs. Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX). Here we use photodynamic imaging, mass spectrometry, parasite gene disruption, and chemical probes to reveal that vestigial host enzymes in the cytoplasm of Plasmodium-infected erythrocytes contribute to ALA-stimulated heme biosynthesis and that ALA uptake depends on parasite-established permeability pathways. We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen. This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations.

No MeSH data available.


Related in: MedlinePlus

Efficacy of CL-PDT with drug-resistant parasites.Effect of 100 µM ALA, 750 µM luminol, 50 µM 4-iodophenol, 50 µM SA (all 0.2% DMSO) and their combination on the growth of asynchronous (A) Dd2 parasites or (B) Kelch-13 I543T (MRA-1241) parasites.DOI:http://dx.doi.org/10.7554/eLife.09143.031
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fig7s4: Efficacy of CL-PDT with drug-resistant parasites.Effect of 100 µM ALA, 750 µM luminol, 50 µM 4-iodophenol, 50 µM SA (all 0.2% DMSO) and their combination on the growth of asynchronous (A) Dd2 parasites or (B) Kelch-13 I543T (MRA-1241) parasites.DOI:http://dx.doi.org/10.7554/eLife.09143.031

Mentions: The development of parasite resistance to frontline antimalarial drugs continues to hamper malaria treatment and eradication efforts worldwide. To test whether a CL-PDT mechanism remains effective against parasites with diverse resistance to distinct drugs, we turned to studies with Dd2 parasites, which have multidrug resistance to antifolate and quinolone antibiotics (Sidhu et al., 2002), and a clinical isolate containing a kelch-13 protein mutation that confers artemisinin tolerance (Ariey et al., 2014). In both parasite lines, combination treatment with ALA, luminol, and 4-iodophenol potently ablated parasite growth (Figure 7—figure supplement 4).


Deconvoluting heme biosynthesis to target blood-stage malaria parasites.

Sigala PA, Crowley JR, Henderson JP, Goldberg DE - Elife (2015)

Efficacy of CL-PDT with drug-resistant parasites.Effect of 100 µM ALA, 750 µM luminol, 50 µM 4-iodophenol, 50 µM SA (all 0.2% DMSO) and their combination on the growth of asynchronous (A) Dd2 parasites or (B) Kelch-13 I543T (MRA-1241) parasites.DOI:http://dx.doi.org/10.7554/eLife.09143.031
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4532139&req=5

fig7s4: Efficacy of CL-PDT with drug-resistant parasites.Effect of 100 µM ALA, 750 µM luminol, 50 µM 4-iodophenol, 50 µM SA (all 0.2% DMSO) and their combination on the growth of asynchronous (A) Dd2 parasites or (B) Kelch-13 I543T (MRA-1241) parasites.DOI:http://dx.doi.org/10.7554/eLife.09143.031
Mentions: The development of parasite resistance to frontline antimalarial drugs continues to hamper malaria treatment and eradication efforts worldwide. To test whether a CL-PDT mechanism remains effective against parasites with diverse resistance to distinct drugs, we turned to studies with Dd2 parasites, which have multidrug resistance to antifolate and quinolone antibiotics (Sidhu et al., 2002), and a clinical isolate containing a kelch-13 protein mutation that confers artemisinin tolerance (Ariey et al., 2014). In both parasite lines, combination treatment with ALA, luminol, and 4-iodophenol potently ablated parasite growth (Figure 7—figure supplement 4).

Bottom Line: Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX).We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen.This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology, Washington University School of Medicine, St Louis, United States.

ABSTRACT
Heme metabolism is central to blood-stage infection by the malaria parasite Plasmodium falciparum. Parasites retain a heme biosynthesis pathway but do not require its activity during infection of heme-rich erythrocytes, where they can scavenge host heme to meet metabolic needs. Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX). Here we use photodynamic imaging, mass spectrometry, parasite gene disruption, and chemical probes to reveal that vestigial host enzymes in the cytoplasm of Plasmodium-infected erythrocytes contribute to ALA-stimulated heme biosynthesis and that ALA uptake depends on parasite-established permeability pathways. We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen. This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations.

No MeSH data available.


Related in: MedlinePlus