Substrate and inhibitor specificity of the Plasmodium berghei equilibrative nucleoside transporter type 1

Avish Arora, Roman Deniskin, Yvett Sosa, Sita Nirupama Nishtala, Philipp P. Henrich, T. R. Santha Kumar, David A. Fidock, Myles Akabas

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Malaria is a critical public health issue in the tropical world, causing extensive morbidity and mortality. Infection by unicellular, obligate intracellular Plasmodium parasites causes malaria. The emergence of resistance to current antimalarial drugs necessitates the development of novel therapeutics. A potential novel drug target is the purine import transporter. Because Plasmodium parasites are purine auxotrophic, they must import purines from their host to fulfill metabolic requirements. They import purines via equilibrative nucleoside transporter 1 (ENT1) homologs. Recently, we used a yeast-based high-throughput screen to identify inhibitors of the P. falciparum ENT1 (PfENT1) that kill P. falciparum parasites in culture. P. berghei infection of mice is an animal model for human malaria. Because P. berghei ENT1 (PbENT1) shares only 60% amino acid sequence identity with PfENT1, we sought to characterize PbENT1 and its sensitivity to our PfENT1 inhibitors. We expressed PbENT1 in purine auxotrophic yeast and used radiolabeled substrate uptake to characterize its function. We showed that PbENT1 transports both purines and pyrimidines. It preferred nucleosides compared with nucleobases. Inosine (IC50 = 3.7 μM) and guanosine (IC50 =21.3 μM) had the highest affinities. Our recently discovered PfENT1 inhibitors were equally effective against both PbENT1- and PfENT1-mediated purine uptake. The PfENT1 inhibitors are at least 10-fold more potent against PfENT1 than human hENT1. They kill P. berghei parasites in 24-hour ex vivo culture. Thus, the P. berghei murine malaria model may be useful to evaluate the efficacy of PfENT1 inhibitors in vivo and their therapeutic potential for treatment of malaria.

Original languageEnglish (US)
Pages (from-to)678-685
Number of pages8
JournalMolecular Pharmacology
Volume89
Issue number6
DOIs
StatePublished - Jun 1 2016

Fingerprint

Equilibrative Nucleoside Transporter 1
Plasmodium berghei
Substrate Specificity
Malaria
Purines
Parasites
Plasmodium
Inhibitory Concentration 50
Yeasts
Inosine
Pyrimidines
Guanosine
Antimalarials
Nucleosides
Amino Acid Sequence
Animal Models
Public Health
Morbidity

ASJC Scopus subject areas

  • Pharmacology
  • Molecular Medicine

Cite this

Substrate and inhibitor specificity of the Plasmodium berghei equilibrative nucleoside transporter type 1. / Arora, Avish; Deniskin, Roman; Sosa, Yvett; Nishtala, Sita Nirupama; Henrich, Philipp P.; Santha Kumar, T. R.; Fidock, David A.; Akabas, Myles.

In: Molecular Pharmacology, Vol. 89, No. 6, 01.06.2016, p. 678-685.

Research output: Contribution to journalArticle

Arora, A, Deniskin, R, Sosa, Y, Nishtala, SN, Henrich, PP, Santha Kumar, TR, Fidock, DA & Akabas, M 2016, 'Substrate and inhibitor specificity of the Plasmodium berghei equilibrative nucleoside transporter type 1', Molecular Pharmacology, vol. 89, no. 6, pp. 678-685. https://doi.org/10.1124/mol.115.101386
Arora, Avish ; Deniskin, Roman ; Sosa, Yvett ; Nishtala, Sita Nirupama ; Henrich, Philipp P. ; Santha Kumar, T. R. ; Fidock, David A. ; Akabas, Myles. / Substrate and inhibitor specificity of the Plasmodium berghei equilibrative nucleoside transporter type 1. In: Molecular Pharmacology. 2016 ; Vol. 89, No. 6. pp. 678-685.
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