Energy production in the rapidly dividing forms of pathogenic African trypanosomes is totally dependent upon glycolysis. This normally depends on an unusual mitochondrial electron transport system and when this is not operating on an unusual method of glycerol production. In the long slender bloodstream trypanosome tbe electron transport system contains only two enzymes, glycerol-3-phosphate dehydrogenase and the trypanosome alternative oxidase (TAO). The TAO and the production of glycerol are two metabolic steps not shared by the host but essential to the parasite. These steps are, therefore, ideal targets for chemotherapy. The production of glycerol is thought to be by a reversal of glycerol kinase but little is known of the TAO other than its similarity to the alternative oxidase of some higher plants, fungi and algae. For this reason, we plan a study of the TAO and its inhibitors. The information gained is expected to allow clear biochemical differences between host and parasite to be exploited leading to a highly selective therapy. Trypanosoma brucei brucei will be used as a model to achieve two primary objectives. The first is to isolate, characterize, and finally reconstitute the electron transport system. The second is to evaluate a limited number of inhibitors for utility as drug candidates. The glycerol-3-phosphate dehydrogenase and the TAO components of the electron transport chain will be released from the mitochondrial membranes of T. b. brucei bloodstream cells. They will be separated and then a functioning system will be reconstituted from the isolated components. A study will be made of the mechanism whereby the oxidase component of the chain is inhibited, the resulting information being used in the eventual design of improved inhibitors. A promising lead for a practical inhibitor of the TAO has developed: the N-n-alkyl 3,4dihydroxybenzamides. A high cure rate has been achieved with one of these, N-n-butyl 3,4dihydroxybenzamide. This compound will be evaluated further and several closely related compounds will be examined for utility as chemotherapeutic agents.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI017899-04A5
Application #
3127516
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1983-04-01
Project End
1993-12-31
Budget Start
1991-01-01
Budget End
1991-12-31
Support Year
4
Fiscal Year
1991
Total Cost
Indirect Cost
Name
New York University
Department
Type
Schools of Medicine
DUNS #
004514360
City
New York
State
NY
Country
United States
Zip Code
10012
Pollakis, G; Grady, R W; Dieck, H A et al. (1995) Competition between inhibitors of the trypanosome alternative oxidase (TAO) and reduced coenzyme Q9. Biochem Pharmacol 50:1207-10
Chan, M M; Grogl, M; Chen, C C et al. (1993) Herbicides to curb human parasitic infections: in vitro and in vivo effects of trifluralin on the trypanosomatid protozoans. Proc Natl Acad Sci U S A 90:5657-61
Grady, R W; Bienen, E J; Dieck, H A et al. (1993) N-n-alkyl-3,4-dihydroxybenzamides as inhibitors of the trypanosome alternative oxidase: activity in vitro and in vivo. Antimicrob Agents Chemother 37:1082-5
Bienen, E J; Saric, M; Pollakis, G et al. (1991) Mitochondrial development in Trypanosoma brucei brucei transitional bloodstream forms. Mol Biochem Parasitol 45:185-92
Clarkson Jr, A B; Bienen, E J; Pollakis, G et al. (1989) Respiration of bloodstream forms of the parasite Trypanosoma brucei brucei is dependent on a plant-like alternative oxidase. J Biol Chem 264:17770-6
Clarkson Jr, A B; Bienen, E J; Pollakis, G et al. (1989) Trypanocidal CoQ analogues: their effect on other mitochondrial systems. Comp Biochem Physiol B 94:245-51
Grady, R W; Bienen, E J; Clarkson Jr, A B (1986) p-Alkyloxybenzhydroxamic acids, effective inhibitors of the trypanosome glycerol-3-phosphate oxidase. Mol Biochem Parasitol 19:231-40