Parasite Genetics and Adaptions - Project B8

Exploring species an stage-dependent differences in the pantothenate requirement of malaria parasite

Host lab: Christina Spry and Kevin Saliba (Research School of Biology, ANU, Canberra)

Partner labs: Alyssa Ingmundson (Department of Biology, Humboldt University, Berlin) and Martin Blume (Robert Koch-Institute, Berlin).

Interaction partners: Kai Matuschewski (Department of Biology, Humboldt University, Berlin) and Edda Klipp (Department of Biology, Humboldt University, Berlin)

Background and aim: Intraerythrocytic-stage Plasmodium falciparum has an absolute requirement for pantothenate, the precursor to the fundamental enzyme cofactor coenzyme A (CoA). We have previously shown that P. falciparum converts exogenous pantothenate into CoA and that the CoA synthesised in the host erythrocyte is unlikely to meet the parasite’s requirement [1].  Despite this, the enzymes predicted to catalyse the first three steps of the pathway have been demonstrated to be dispensable during the blood stage of mouse malaria parasites and essential only for development in the mosquito [2–4].  In this study we aim to understand the apparent species and stage-dependent differences in the pantothenate requirement of Plasmodium parasites, which in turn will inform drug discovery efforts targeting pantothenate utilisation.

Methods: We will perform metabolic labelling studies and use liquid chromatography-mass spectrometry to track CoA biosynthesis within wild-type and CoA biosynthesis gene-disrupted Plasmodium parasites and their host cells.  We will explore the possibility that at least some Plasmodium parasites can salvage CoA and/or intermediates of the CoA biosynthesis pathway.  Additionally, we will investigate the metabolic fate of pantothenate and/or any pantothenate derivatives utilised by the parasite, to determine the key functions of CoA in different stages of the Plasmodium lifecycle.  We will also study pathway flux to identify vulnerabilities in the CoA biosynthesis pathway that could be exploited for drug design, and use the information gained to understand the mechanism of action of pantothenate analogues previously shown to be potent inhibitors of parasite growth.

Plan:

Canberra

• Uptake and metabolism studies of wild-type human malaria parasites (blood stage).
• Measurement of endogenous CoA biosynthesis metabolites in host cells.
• Investigations into the impact of inhibitors on CoA biosynthesis.

Berlin

• Uptake and metabolism studies of wild-type and CoA biosynthesis gene-disrupted murine malaria parasites (blood, liver and mosquito stages).

References:

[1]       Spry C, Saliba KJ. (2009) J Biol Chem, 284(37):24904-13

[2]       Hart RJ, Cornillot E, Abraham A, Molina E, Nation CS, Ben Mamoun C, Aly AS. (2016)

Sci Rep, 20(6):33518

[3]        Srivastava A, Philip N, Hughes KR, Georgiou K, MacRae JI, Barrett MP, Creek DJ, McConville MJ, Waters AP. (2016) PLoS Pathog,12(12):e1006094

[4]       Hart RJ, Abraham A, Aly ASI. (2017) Front Cell Infect Microbiol, 20(7):260.

Keywords: Coenzyme A biosynthesis, drug target, salvage, liquid chromatography-mass spectrometry, metabolic labelling