The malarial parasite infects 10% of the worlds population and is responsible for 2-4 million deaths in over 80 nations each year. The wide-spread emergence of drug resistance to the parasite severely limits treatment options, and there is a clear need to develop new anti-malarial agents. Unlike mammalian cells, the malaria parasite cannot salvage preformed pyrimidine bases or nucleosides, and pyrimidines are exclusively synthesized by the de novo pathway. The importance of the pyrimidine biosynthetic pathway to the survival of the malarial parasite is demonstrated by the finding that dihydrofolate reductase is a validated target for the treatment of the parasite. For these reasons any of the key enzymes in the pathway are potential drug targets. However, several factors make the fourth step, catalyzed by dihydroorotate dehydrogenase (DHODH) particularly attractive. DHODH has been successfully exploited as a drug target for the treatment of rheumatoid arthritis. The enzyme has been well characterized from a number of bacterial and eukaryotic sources. X-ray structures are available for several family members, and a larger number of inhibitors have been generated. The crystallographic data suggest that the enzymes from different species have very divergent inhibitor binding sites, and species selective inhibitors have been published for human and several bacterial enzymes.
The aims of this grant are to validate DHODH as a target for treatment of the malarial parasite, and to identify potent and selective inhibitors of the enzyme that have activity against the parasite. The proposed studies will be broad ranging and will require the expertise and resources of two laboratories to accomplish. The studies include: 1) biochemical and structural characterization of recombinant malarial DHODH, 2) testing identified DHODH inhibitors to determine if they have anti-malarial activity, and development of structure/activity relationships that correlate enzyme inhibition with cell effects, 3) comparison of the metabolic consequence of gene knockout to the effects of inhibitors by microarray analysis, and 4) generation of parasites that are resistant to DHODH inhibitors.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI053680-01A2
Application #
6787575
Study Section
Special Emphasis Panel (ZRG1-IDM-H (03))
Program Officer
Coyne, Philip Edward
Project Start
2004-04-01
Project End
2009-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
1
Fiscal Year
2004
Total Cost
$130,998
Indirect Cost
Name
University of Texas Sw Medical Center Dallas
Department
Pharmacology
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
Guler, Jennifer L; White 3rd, John; Phillips, Margaret A et al. (2015) Atovaquone tolerance in Plasmodium falciparum parasites selected for high-level resistance to a dihydroorotate dehydrogenase inhibitor. Antimicrob Agents Chemother 59:686-9
Das, Priyabrata; Deng, Xiaoyi; Zhang, Liang et al. (2013) SAR Based Optimization of a 4-Quinoline Carboxylic Acid Analog with Potent Anti-Viral Activity. ACS Med Chem Lett 4:517-521
Guler, Jennifer L; Freeman, Daniel L; Ahyong, Vida et al. (2013) Asexual populations of the human malaria parasite, Plasmodium falciparum, use a two-step genomic strategy to acquire accurate, beneficial DNA amplifications. PLoS Pathog 9:e1003375
Marwaha, Alka; White, John; El Mazouni, Farah et al. (2012) Bioisosteric transformations and permutations in the triazolopyrimidine scaffold to identify the minimum pharmacophore required for inhibitory activity against Plasmodium falciparum dihydroorotate dehydrogenase. J Med Chem 55:7425-36
Coteron, Jose M; Marco, Maria; Esquivias, Jorge et al. (2011) Structure-guided lead optimization of triazolopyrimidine-ring substituents identifies potent Plasmodium falciparum dihydroorotate dehydrogenase inhibitors with clinical candidate potential. J Med Chem 54:5540-61
Ganesan, Suresh M; Morrisey, Joanne M; Ke, Hangjun et al. (2011) Yeast dihydroorotate dehydrogenase as a new selectable marker for Plasmodium falciparum transfection. Mol Biochem Parasitol 177:29-34
Phillips, Margaret A; Rathod, Pradipsinh K (2010) Plasmodium dihydroorotate dehydrogenase: a promising target for novel anti-malarial chemotherapy. Infect Disord Drug Targets 10:226-39
Guiguemde, W Armand; Shelat, Anang A; Bouck, David et al. (2010) Chemical genetics of Plasmodium falciparum. Nature 465:311-5
Booker, Michael L; Bastos, Cecilia M; Kramer, Martin L et al. (2010) Novel inhibitors of Plasmodium falciparum dihydroorotate dehydrogenase with anti-malarial activity in the mouse model. J Biol Chem 285:33054-64
Deng, Xiaoyi; Gujjar, Ramesh; El Mazouni, Farah et al. (2009) Structural plasticity of malaria dihydroorotate dehydrogenase allows selective binding of diverse chemical scaffolds. J Biol Chem 284:26999-7009

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