To rapidly develop new and better therapies to combat drug resistant malaria, we must fully elucidate the molecular mechanisms of antimalarial action and antimalarial drug resistance. In addition, more rapid and convenient biochemical and physiological assays for various antimalarial drug resistance phenotypes are desperately needed. Both of these issues are effectively addressed via more detailed, single-cell level analysis of malarial parasite physiology and biophysics. We thus propose a detailed analysis of transport, pH, and membrane potential phenomena in living intraerythrocytic malarial parasites using modern subcellular imaging and single - cell photometry methods. Specifically, we will: 1) Test putative relationships between cytosolic and vacuolar pH (pHcyt, pHvac) and membrane potentials of living intraerythrocytic P. falciparum and resistance to antimalarial drugs using single-cell photometry of cells under constant perfusion and laser confocal microscopy. 2) Elucidate ion dependencies, inhibitor sensitivities, and kinetic characteristics of pHcyt, pHvac, and membrane potential regulation. 3) Test conclusions from 1,2 using progeny of genetic cross between resistant and sensitive parasites. 4) Define effects of antimalarial drugs and reversal agents on biophysical parameters. 5) Compare and contrast measurement with laboratory strains vs. field isolates of P. falciparum and P. vivax. Along with defining the ion - transport physiology of drug resistant parasites, these experiments will be performed with an eye towards development of principles that will aid in the rapid, """"""""field compatible"""""""", diagnosis of drug resistant malaria.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI045957-04
Application #
6632033
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Program Officer
Coyne, Philip Edward
Project Start
2000-03-01
Project End
2005-02-28
Budget Start
2003-03-01
Budget End
2005-02-28
Support Year
4
Fiscal Year
2003
Total Cost
$195,000
Indirect Cost
Name
Georgetown University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
Sherlach, Katy S; Roepe, Paul D (2014) Determination of the cytostatic and cytocidal activities of antimalarial compounds and their combination interactions. Curr Protoc Chem Biol 6:237-48
Roepe, Paul D (2014) To kill or not to kill, that is the question: cytocidal antimalarial drug resistance. Trends Parasitol 30:130-5
Gaviria, David; Paguio, Michelle F; Turnbull, Lindsey B et al. (2013) A process similar to autophagy is associated with cytocidal chloroquine resistance in Plasmodium falciparum. PLoS One 8:e79059
Gorka, Alexander P; Alumasa, John N; Sherlach, Katy S et al. (2013) Cytostatic versus cytocidal activities of chloroquine analogues and inhibition of hemozoin crystal growth. Antimicrob Agents Chemother 57:356-64
Sinai, Anthony P; Roepe, Paul D (2012) Autophagy in Apicomplexa: a life sustaining death mechanism? Trends Parasitol 28:358-64
Ghosh, Debasish; Walton, Julia L; Roepe, Paul D et al. (2012) Autophagy is a cell death mechanism in Toxoplasma gondii. Cell Microbiol 14:589-607
Roepe, Paul D (2011) PfCRT-mediated drug transport in malarial parasites. Biochemistry 50:163-71
Paguio, Michelle F; Bogle, Kelly L; Roepe, Paul D (2011) Plasmodium falciparum resistance to cytocidal versus cytostatic effects of chloroquine. Mol Biochem Parasitol 178:1-6
Alumasa, John N; Gorka, Alexander P; Casabianca, Leah B et al. (2011) The hydroxyl functionality and a rigid proximal N are required for forming a novel non-covalent quinine-heme complex. J Inorg Biochem 105:467-75
Paguio, Michelle F; Cabrera, Mynthia; Roepe, Paul D (2009) Chloroquine transport in Plasmodium falciparum. 2. Analysis of PfCRT-mediated drug transport using proteoliposomes and a fluorescent chloroquine probe. Biochemistry 48:9482-91

Showing the most recent 10 out of 30 publications