title: A targeted peptide nucleic acid to down-regulate mouse microsomal triglyceride transfer protein expression in hepatocytes.
abstract: Peptide nucleic acids (PNA's) have shown to hold potential as antisense drugs. In this study we have designed PNA drugs for the microsomal triglyceride transfer protein (MTP), which is known to play a critical role in the assembly of atherogenic lipoproteins, and have converted the most potent drug into a liver-targeted prodrug. First, we have synthesized three PNA sequences targeting domains on the mouse MTP mRNA, which were not involved in intrastrand base-pairing interactions as jugded from its secondary structure. Only one of the PNA's, PNA569, showed dose-dependent inhibition of MTP expression in a cell-free system for coupled transcription/translation of MTP. Second, to improve the cellular uptake of this PNA drug, we have conjugated PNA569 to a high affinity ligand for the asialoglycoprotein receptor, K(GalNAc)(2). As compared to the parent PNA, the prodrug PNA-K(GalNAc)(2) was found to display to a markedly improved capacity to inhibit MTP mRNA expression in parenchymal liver cells. A glycoconjugated nonsense control appeared to be ineffective. In conclusion, the design of a targeted PNA is described to reduce MTP expression in parenchymal liver cells by 70%. The presented approach for targeted tissue-specific down-regulation of genes by PNA's may be valid for other genes as well.
authors: Leiden/Amsterdam Center for Drug Research, Division of Biopharmaceutics, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors: Sabine M W
authors: SM
authors: van Rossenberg
authors: Karen M
authors: KM
authors: Sliedregt-Bol
authors: Perry
authors: P
authors: Prince
authors: Theo J C
authors: TJ
authors: van Berkel
authors: Jacques H
authors: JH
authors: van Boom
authors: Gijs A
authors: GA
authors: van der Marel
authors: Erik A L
authors: EA
authors: Biessen
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000187:drug effects / Q000235:genetics*; D016373:DNA, Antisense; D015536:Down-Regulation; D016503:Drug Delivery Systems; D015195:Drug Design; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D020135:Peptide Nucleic Acids / Q000138:chemical synthesis / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D016373:DNA, Antisense; D020135:Peptide Nucleic Acids; D012333:RNA, Messenger; C106092:microsomal triglyceride transfer protein