Download Unravelling the molecular pathways of Plasmodium falciparum programmed cell death: identification of novel therapeutic targets.

NUS Graduate School for Integrative Sciences and Engineering
Research Project Write-up
Title of Project :
Unravelling the Molecular Pathways of Plasmodium
falciparum Programmed Cell Death: Identification of
Novel Therapeutic Targets
Name of Supervisor :
Dr. Kevin SW Tan
Contact Details:
[email protected]
Short Description
Programmed cell death (PCD) is now accepted as a well-established phenomenon among the
Protozoa. Despite recent reports strongly suggesting that PCD occurs in the malaria protozoan
parasite Plasmodium falciparum, there is limited information on pathways and molecules that
induce plasmodium cell death. The objectives of this study are to perform morphological
characterization of P. falciparum PCD using transgenic parasites, to delineate the PCD
pathway(s) (caspase-dependent and/or caspase-independent), and to identify and characterize
plasmodial genes and proteins implicated in malaria PCD. We hypothesize that P. falciparum
exhibits multiple cell death activation pathways of which unique molecular regulators are
potential candidates for intervention strategies. Preliminary studies in our laboratory have
suggested that the antimalarial chloroquine and mammalian apoptosis inducer staurosporine
induce apoptosis-like features in P. falciparum erythrocytic stages, including early loss of
mitochondrial outer membrane potential and caspase-like activity. Therefore, we proposed to
initiate our study by PCD induction using a variety of drugs and assaying for typical apoptotic
features including externalization of phospatidylserine, loss of mitochondria transmembrane
potential, caspase-like activity, DNA fragmentation, and cell membrane changes. The use of
specific inhibitors and substrates to caspase or non-caspase proteases with these assays will
aid in understanding the nature of PCD-associated molecules and in delineating parasite PCD
pathways. We will also characterize the function of malaria metacaspase (PfMCA1) gene in
relation to its apoptotic function via functional heterologous complementation of YCA1
(ScMCA1) metacaspase KO Saccharomyces cerevisiae mutants. Additionally, novel
mediators of malaria PCD will be identified via microarray analysis and the use of
biotinylated caspase/ cysteine protease inhibitors. Establishment of a functional link between
these molecules and malaria PCD will allow them to serve as potential chemotherapeutic
targets for pharmacological activators that selectively induce/upregulate the cell death
machinery in the parasite, hence limiting growth and ameliorating the disease they cause.