The infections caused by parasitic protozoa place a severe burden of illness in the World's population. Many of these infections, although not directly fatal, induce extreme morbidity in infected individuals. Current regimens for the treatment of the majority of these diseases are dogged by recurring problems of drug toxicity and side effects, and widespread development of drug-resistance with a restricted spectrum of active compounds. These problems can only intensify therefore it is vital that new targets and novel compounds be developed into antiparasite drugs as soon as possible. This current Program application entitled """"""""Exploitation of Novel Drug Targets in Protozoal Infections"""""""" proposes to address these specific problems for malaria, leishmaniasis and amebiasis. The projects show a high degree of unity based on mutually complementary skills, shared goals, and a preexisting interaction between the 4 individual laboratories. All projects propose to target enzymes that have already been identified and show activities that are specific to the parasite. Project 1 has two complementary aims; The exploitation of macrophage-restricted receptors to target active compounds to the endocytic network of Leishmania-infected macrophages, and the development of substrates specific to the parasite's cysteine proteinases as inhibitors of enzyme activity. These activities are required for the growth of axenic amastigotes in culture. Project 2 exploits the requirement for the aspartic hemoglobinase in the degradation of host erythrocyte hemoglobin by the parasite Plasmodium falciparum. To develop a new antimalarials, this project proposes to improve on peptidomimetic inhibitors that have been shown to block parasite growth in culture. Project 3 is aimed analyzing the interactions between the Entameba histolytica cysteine proteinases, which are fundamental to the pathology of invasive amebiasis, with laminin. The investigators propose to identify the region(s) of laminin involved in the tight binding with amebal proteinases to facilitate development of Entameba-specific proteinase inhibitors. Project 4 targets a vital bifunctional alcohol dehydrogenase/acetyl coA reductase, unique to Entameba histolytica, as a novel site a drug action. Sequence analysis of the enzyme reveals homology only with anaerobic prokaryote enzymes suggesting that the alcohol dehydrogenase/acetyl coA reductase will be a specific target. Together these projects combine to exploit the common interest of the Project Leaders and make most efficient use of their broad experience in the diverse disciplines required for effective drug development.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Program Projects (P01)
Project #
5P01AI037977-04
Application #
2672504
Study Section
Special Emphasis Panel (SRC (80))
Project Start
1995-05-01
Project End
2000-04-30
Budget Start
1998-05-01
Budget End
2000-04-30
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Washington University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
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Davis, Paul H; Schulze, Jochen; Stanley Jr, Samuel L (2007) Transcriptomic comparison of two Entamoeba histolytica strains with defined virulence phenotypes identifies new virulence factor candidates and key differences in the expression patterns of cysteine proteases, lectin light chains, and calmodulin. Mol Biochem Parasitol 151:118-28
Davis, Paul H; Zhang, Xiaochun; Guo, Jianhua et al. (2006) Comparative proteomic analysis of two Entamoeba histolytica strains with different virulence phenotypes identifies peroxiredoxin as an important component of amoebic virulence. Mol Microbiol 61:1523-32
Espinosa, A; Yan, L; Zhang, Z et al. (2001) The bifunctional Entamoeba histolytica alcohol dehydrogenase 2 (EhADH2) protein is necessary for amebic growth and survival and requires an intact C-terminal domain for both alcohol dahydrogenase and acetaldehyde dehydrogenase activity. J Biol Chem 276:20136-43
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Hill, K L; Hutchings, N R; Russell, D G et al. (1999) A novel protein targeting domain directs proteins to the anterior cytoplasmic face of the flagellar pocket in African trypanosomes. J Cell Sci 112 Pt 18:3091-101
Selzer, P M; Pingel, S; Hsieh, I et al. (1999) Cysteine protease inhibitors as chemotherapy: lessons from a parasite target. Proc Natl Acad Sci U S A 96:11015-22
Schaible, U E; Schlesinger, P H; Steinberg, T H et al. (1999) Parasitophorous vacuoles of Leishmania mexicana acquire macromolecules from the host cell cytosol via two independent routes. J Cell Sci 112 ( Pt 5):681-93
Tyas, L; Gluzman, I; Moon, R P et al. (1999) Naturally-occurring and recombinant forms of the aspartic proteinases plasmepsins I and II from the human malaria parasite Plasmodium falciparum. FEBS Lett 454:210-4

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