Grant: $287,414 - National Institutes of Health - Jul. 17, 2009
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Award Description: This proposal outlines a comprehensive plan to genetically dissect the fatty acid metabolism of the human pathogen Toxoplasma gondii. T. gondii infection is widespread in the U.S. (22% of the population is chronically infected) and while usually benign can cause life-threatening disease in immunosuppressed individuals (e.g. those with HIV-AIDS, transplant recipients, or hematological malignancies). Congenital transmission of T. gondii is also a major public health concern. Highly virulent parasite strains have been recently identified as the cause of severe and recurring eye infections that ultimately lead to blindness. T. gondii also has the potential to cause significant waterborne outbreaks and has been listed by the CDC as a potential bioterrorism pathogen (appendix B). The currently available treatment has frequent and significant adverse effects and shows no efficacy in chronic infection, thus allowing for recrudescence of the active infection. Thus, new drugs are urgently needed. The discovery of a chloroplast-like organelle in apicomplexan parasites provides several promising parasite-specific target pathways for drug development. Among these pathways is a bacterial type II fatty acid synthesis pathway, and enzymes in this pathway have been the subject of intensive medicinal chemistry efforts to develop drugs against malaria and toxoplasmosis. However, what the precise function of this pathway for T. gondii and related apicomplexan parasites is remains unclear. Furthermore, the parasite genome encodes additional enzyme systems that might supply fatty acids either by synthesis or salvage from the host cell. A detailed understanding of the function and relative importance of these pathways is needed to guide the drug development effort to the most promising targets. In this project we will use genetics and metabolomics to dissect the complex interaction of three individual pathways. Using a novel and highly efficient approach to engineer conditional T. gondii mutants we will rigorously test the importance and function of each individual pathway in vivo. We will determine the impact of the loss of specific pathways on the parasite fatty acid and lipid composition using unbiased metabolomic profiling. To define the interactions between individual pathways and between the parasite and its host cell we conduct metabolic flux studies using stable epitope tracing. Overall we expect the outlined studies to produce a detailed mechanistic understanding of fatty acid synthesis as an important part of parasite metabolism and metabolic host-parasite interaction. Mutant analysis will highlight truly essential components as potential pharmacological targets. We also expect that the genetic and metabolomic tools honed along the way will prove highly useful for the dissection of many facets of parasite biology beyond lipid metabolism.
Project Description: The project started on August 1, 2009. During this two month two graduate student researchers worked on this project and we are actively engaged in recruiting a postdoctoral fellow. We generated two new mutants in the T. gondii fatty acid elongation pathway and we have biochemically characterized one of these mutants with additional experiments under way. We also note that the parent proposal to this bridge funding has received an outstanding 3%tile merrit score and will in all likelihood be funded.
Jobs Summary: Graduate student researcher. This projects funds and retains the postions of two graduate student researchers. Postdoctoral Researcher. A new position for a postdoctoral researcher was created and the postion was advertised. We are currently conducting interviews with candidates. (Total jobs reported: 1)
Project Status: Less Than 50% Completed
This award's data was last updated on Jul. 17, 2009. Help expand these official descriptions using the wiki below.