In this project we will characterize the Plasmodium falciparum cysteine protease falcipain and evaluate this enzyme as a potential target for antimalarial chemotherapy. We have previously identified falcipain as a hemoglobinase and shown that falcipain inhibitors block hemoglobin degradation and parasite development, suggesting that falcipain is an essential enzyme and logical chemotherapeutic target. The testing of falcipain inhibitors as antimalarial is ongoing. However, it is also important to better characterize the biochemical properties and biological role of this enzyme, as these data will improve our ability to design and test falcipain inhibitors.
Specific aims of this project will be: (1) to characterize the biochemical properties of native and recombinant falcipain, (2) to evaluate the biological role of falcipain, and (3) to test falcipain inhibitors as potential antimalarial drugs. The project will allow us to rigorously test two hypotheses. First, we hypothesize that falcipain is an essential plasmodial hemoglobinase that is responsible for early cleavages of hemoglobin and is required for parasite development. Second, we hypothesize that falcipain inhibitors will be effective antimalarial drugs. The experiments outlined in this proposal should provide a clear characterization of the biochemical properties and biological role of falcipain. In addition, the planned evaluation of the effects of falcipain inhibitors on cultured parasites and animal models of malaria should critically test this enzyme as a chemotherapeutic target. This evaluation is also likely to identify specific falcipain inhibitors with potent antimalarial activity that will be ready for initial testing against human malaria.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI035800-08
Application #
6373380
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Program Officer
Gottlieb, Michael
Project Start
1994-07-01
Project End
2004-06-30
Budget Start
2001-07-01
Budget End
2002-06-30
Support Year
8
Fiscal Year
2001
Total Cost
$319,930
Indirect Cost
Name
University of California San Francisco
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Boyom, Fabrice Fekam; Fokou, Patrick Valere Tsouh; Yamthe, Lauve Rachel Tchokouaha et al. (2011) Potent antiplasmodial extracts from Cameroonian Annonaceae. J Ethnopharmacol 134:717-24
Guantai, Eric M; Ncokazi, Kanyile; Egan, Timothy J et al. (2011) Enone- and chalcone-chloroquinoline hybrid analogues: in silico guided design, synthesis, antiplasmodial activity, in vitro metabolism, and mechanistic studies. J Med Chem 54:3637-49
Sijwali, Puran Singh; Rosenthal, Philip J (2010) Functional evaluation of Plasmodium export signals in Plasmodium berghei suggests multiple modes of protein export. PLoS One 5:e10227
Kerr, Iain D; Lee, Ji H; Farady, Christopher J et al. (2009) Vinyl sulfones as antiparasitic agents and a structural basis for drug design. J Biol Chem 284:25697-703
Dude, Marie-Adrienne; Kaeppler, Ulrich; Herb, Monika et al. (2009) Synthesis and evaluation of non-peptidic cysteine protease inhibitors of P. falciparum derived from etacrynic acid. Molecules 14:19-35
Kerr, Iain D; Lee, Ji H; Pandey, Kailash C et al. (2009) Structures of falcipain-2 and falcipain-3 bound to small molecule inhibitors: implications for substrate specificity. J Med Chem 52:852-7
Subramanian, Shoba; Hardt, Markus; Choe, Youngchool et al. (2009) Hemoglobin cleavage site-specificity of the Plasmodium falciparum cysteine proteases falcipain-2 and falcipain-3. PLoS One 4:e5156