Identification of serine hydrolases involved in Plasmodium host cell invasion


Principal Investigator: Brooke Anderson-White
Abstract: DESCRIPTION (provided by applicant): Plasmodium falciparum is the parasite responsible for malaria, a disease that continues to devastate all tropical regions of the world. A quarter of a million cases of malaria are reported annually with close to a million of these cases resulting in death. Efforts to control this disease are complicated by growing drug resistance in the parasite, leading to an imminent need for new drug targets. One avenue to the identification of novel targets is to discover and characterize essential enzymes in the parasite by inhibiting them with small molecules. The serine hydrolases are a large family of enzymes with highly reactive and covalently modifiable active sites making them attractive for inhibition with small molecules. Furthermore serine hydrolases are well represented in most organisms including humans where they comprise 1% of all proteins. In P. falciparum two essential serine hydrolases have already been identified, subtilisin-like serine protease 1 (PfSUB1) and 2 (PfSUB2). In order to find additional essential serine hydrolases in the parasite, a library of highly effective serine hydrolase inhibitors in mammals was screened in P. falciparum. This library of triazole urea compounds revealed several compounds that slow or block the growth of P. falciparum. The most efficacious compound, AA691, appears to induce a host cell invasion defect. Furthermore it has been verified that AA691 binds to at least one of the same targets as fluorophosphonate (FP), a generic serine hydrolase inhibitor, in competition assays suggesting this defect is due to inhibition of serine hydrolases. In this project the serine hydrolases inhibited by AA691 will be isolated using a probe based on the structure of AA691 that covalently modifies its targets. The targets will then be identified using tandem orthogonal proteolysis-activity-based protein profilin (TOP-ABPP) and mass spectrometry. The role(s) of these targets in host cell invasion will be characterized in culture through the creation of direct and regulatable conditional knockouts in P. falciparum. The invasion defect will be further verified in vivo with P. berghei mouse infections. Finally the effects of AA691 on the liver stage will be assessed in hepatocyte culture and in vivo. The rising prevalence of P. vivax infection, which remains dormant in the liver leading to relapse after blood stage treatment, is driving a push for therapeutics against liver stage parasites. There is an urgent need for novel malaria therapeutics and the results of this research could lead directly to the development of these drugs.
Funding Period: 2013-07-01 - 2016-06-30
more information: NIH RePORT

Detail Information

Research Grants30

  1. Mechanisms of mosquito midgut invasion by Plasmodium ookinetes
    Marcelo Jacobs-Lorena; Fiscal Year: 2013
    ..Knowledge generated by these studies may have important implications for the development of multivalent transmission-blocking vaccines. ..
  2. Discovery of chemically validated malaria liver stage targets
    Elizabeth A Winzeler; Fiscal Year: 2013
    ..The inability to eliminate cryptic liver forms creates a barrier to malaria eradication. We propose to find new targets that are critical to the liver stages as well as the blood stages with the long term aim of designing better drugs. ..
  3. Role of pfcrt in chloroquine resistance in P. falciparum
    DAVID ARMAND FIDOCK; Fiscal Year: 2013
  4. Population-based Approach to Malaria Research and Control
    Donald J Krogstad; Fiscal Year: 2013
    ..Understanding these relationships is critical to both the evaluation of current intervention effectiveness and in the translation of new tools for prevention and treatment of the disease and its transmission. ..
  5. Development of Small Antimicrobial Peptide Mimics as Drug-Resistant and Susceptib
    Richard W Scott; Fiscal Year: 2013
    ..These therapeutics should prove to be potent, active against resistant parasites and display a low incidence of resistance. ..
  6. Primary Immune Deficiency Treatment Consortium
    Morton Cowan; Fiscal Year: 2013
    ..These studies will resolve critical questions concerning HCT for these disorders and form the basis for future prospective clinical trials. ..
  7. Identifaction of the genetic basis of primaquine resistance in malaria parasites
    ERIKA LEA FLANNERY; Fiscal Year: 2013
    ..These molecular determinants will also inform drug discovery efforts to identify additional liver-stage acting antimalarials. Both applications of the proposed results will aide in the eradication of vivax malaria. ..
  8. University of Maryland Greenebaum Cancer Center Support Grant
    Kevin J Cullen; Fiscal Year: 2013
    ..Reflecting our remarkable and continued growth, UMGCC seeks to renew its CCSG to enhance and expand its efforts in high-quality and clinically relevant cancer research. ..
  9. Ribosome Profiling in Plasmodium falciparum
    Marilyn Parsons; Fiscal Year: 2013
    ..falciparum erythrocytic stages. ..
  10. Malaria Phosphatase Inhibitors Identified as a Potential New Malaria Treatment
    Wei Zheng; Fiscal Year: 2013
    ..falciparum phosphatase will be used in conjunction with high throughput screening assays. These studies will be important for developing chemo prophylaxis directed against a brand new target in a major human pathogen. ..
  11. Drugs targeting erythrocytic and exoerythrocytic stages of malaria
    Roman Manetsch; Fiscal Year: 2013
    ..The three chemotypes possess in vivo liver stage activity, in vivo blood stage activity, gametocytocidal activity, and/or activity in the mosquitoes. ..
  12. New infection-related proteins of Plasmodium sporozoites and liver stages
    Stefan H I Kappe; Fiscal Year: 2013
    ..Identifying major liver stage-host hepatocyte interactions and elucidating their functional significance will reveal fundamental principles of malaria parasite liver infection and provide new avenues for preventive drug design. ..
  13. Chemically Mapping Malarial Rupture Proteases
    Matthew Bogyo; Fiscal Year: 2013
    ..This work will lead to the identification of potentially valuable targets for development of new therapeutic treatment strategies for malaria. ..
  14. Structure and Function of the Circumsporozoite Protein
    Photini Sinnis; Fiscal Year: 2013
    ..Overall these studies will elucidate how CSP functions in the sporozoite[unreadable]s journey from mosquito to mammalian host and should open up new avenues for the control and prevention of malaria. ..
  15. Comparative Biology of Tissue Repair, Regeneration and Aging
    Kevin Strange; Fiscal Year: 2013
    ..The proposed COBRE will greatly enhance MDIBL's growth and development, which in turn will contribute to the continued growth and enhancement of the biomedical research infrastructure in Maine. ..
    Paul Greengard; Fiscal Year: 2013
    ..Results from the three Projects will complement each other. In addition, there will be a significant level of collaboration between the three Projects, as well as close interaction of the three Projects with the Scientific Core. ..
  17. Pacific NorthWest Regional Center of Excellence (PNWRCE)
    Jay A Nelson; Fiscal Year: 2013
    ..pseudomallei host pathogen response during both the septicemic as well as the intracellular phases of the disease. ..
  18. Small molecule protein-glycan inhib. as malaria transmission-blocking therapuetic
  19. Novel Broad-spectrum Antimalarials
    Victor Melendez; Fiscal Year: 2013
    Michal Laniado Schwartzman; Fiscal Year: 2013
    ..ular tone, in the pathophysiology of hypertension and cardiovascular disease. ..
  21. How Toxoplasma injects rhoptry proteins into the host cell
    FELICE DEBORAH KELLY; Fiscal Year: 2013
    ..This machinery is likely to be conserved throughout the Apicomplexa family, just as the invasion machinery is, and proteins identified here may help us understand the invasion of Plasmodium falciparum as well. ..