Use of peptide nucleic acids to manipulate gene expression in the malaria parasite Plasmodium falciparum

PLoS One. 2014 Jan 22;9(1):e86802. doi: 10.1371/journal.pone.0086802. eCollection 2014.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabinonucleosides
  • Blotting, Western
  • Cell Line
  • Cell-Penetrating Peptides / metabolism
  • Drug Delivery Systems / methods
  • Electrophoresis, Polyacrylamide Gel
  • Gene Silencing / drug effects*
  • Luciferases
  • Molecular Structure
  • Peptide Nucleic Acids / chemistry
  • Peptide Nucleic Acids / metabolism
  • Peptide Nucleic Acids / pharmacology*
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / metabolism*
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • 2-amino-9-(2,3-dideoxy-2,3-dihydro-beta-D-arabinofuranosyl)-6-methoxy-9H-purine
  • Arabinonucleosides
  • Cell-Penetrating Peptides
  • Peptide Nucleic Acids
  • Luciferases

Grants and funding

This work was supported by the Chief Scientist, Ministry of Industry and Commerce (Kamin program # 49601). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.