Use of peptide nucleic acids to manipulate gene expression in the malaria parasite Plasmodium falciparum.
One of the major concerns in treating malaria by conventional small drug molecules is the rapid emergence of drug resistance. Specific silencing of essential genes by antisense oliogomers has been proposed as an alternative approach that may result in antimalarial activity which is not associated with drug resistance. In addition, such an approach could be an important biological tool for studying many genes' function by reverse genetics. Here we present a novel methodology of using peptide nucleic acids (PNAs) as a useful tool for gene silencing in Plasmodium falciparum. PNAs, designed as specific antisense molecules, were conjugated to a cell penetrating peptide (CPP); namely, octa-D-lysine via the C-terminus, to allow facile delivery through cell membranes. PNAs added to P. falciparum cultures were found exclusively in infected erythrocytes and were eventually localized in nuclei of the parasites at all stages of intra erythrocytic development. We show that these PNAs specifically down regulated both a stably expressed transgene as well as an endogenous essential gene, which significantly reduced parasites' viability. This study paves the way for a simple approach to silence a variety of P. falciparum genes as means of deciphering their function and potentially to develop highly specific and potent antimalarial agents.
Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
Netanel
N
Kolevzon
Department of Microbiology and Molecular Genetics, The institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Abed
A
Nasereddin
Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
Shankar
S
Naik
Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
Eylon
E
Yavin
Department of Microbiology and Molecular Genetics, The institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Ron
R
Dzikowski
D001087:Arabinonucleosides; D015153:Blotting, Western; D002460:Cell Line; D057846:Cell-Penetrating Peptides / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D020868:Gene Silencing / Q000187:drug effects*; D008156:Luciferases; D015394:Molecular Structure; D020135:Peptide Nucleic Acids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
C585590:2-amino-9-(2,3-dideoxy-2,3-dihydro-beta-D-arabinofuranosyl)-6-methoxy-9H-purine; D001087:Arabinonucleosides; D057846:Cell-Penetrating Peptides; D020135:Peptide Nucleic Acids; D008156:Luciferases