title: Multifunctional peptide-PEG intercalating conjugates: programmatic of gene delivery to the blood-brain barrier.
abstract: OBJECTIVE
  To enhance transfection efficacy of pDNA through the application of multifunctional peptide-PEG-tris-acridine conjugates (pPAC) and the formation of biodegradable core-shell polyplexes for gene delivery to the blood-brain barrier (BBB).
  
  
  METHODS
  pPAC-mediated transfection was compositionally optimized in mouse BBB cells (bEnd.3). Cellular uptake and trafficking, and brain accumulation of pDNA was evaluated by fluorescent imaging and histochemistry. We constructed anti-MRP4 siRNA-producing vectors and evaluated the efficacy of MRP4 down-regulation of MRP4 by Western blot and qPCR, and its effect on the uptake of (3)H-AZT, an MRP4 substrate.
  
  
  RESULTS
  A core-shell gene delivery system (GDS) was assembled from pDNA and pPAC, carrying multifunctional peptides with NLS, TAT, and brain-specific BH, or ApoE sequences, and biodegradable pLPEI polyamine. This GDS demonstrated better cellular and nuclear accumulation, and a 25-fold higher transfection efficacy in slow-dividing bEnd.3 cells compared to ExGen500. Inclusion of brain-targeting pPAC enhanced in vivo accumulation of functional pDNA in brain capillaries. Treatment by encapsulated anti-MRP4 siRNA-producing pDNA caused transient down-regulation of MRP4, and, after intravenous injection in Balb/c mice, enhanced AZT uptake in the brain by 230-270%.
  
  
  CONCLUSIONS
  The pPAC represent novel efficient components of GDS that could find various gene therapy applications, including genetic modulation of the BBB.
authors.affiliation: Center for Drug Delivery and Nanomedicine and Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.forename: Trevor
authors.initials: T
authors.lastname: Gerson
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Varney
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Singh
authors.forename: Serguei V
authors.initials: SV
authors.lastname: Vinogradov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001812:Blood-Brain Barrier; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D015536:Down-Regulation; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010455:Peptides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering; D014162:Transfection; D015215:Zidovudine / Q000493:pharmacokinetics
chemical_list: D004247:DNA; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010455:Peptides; D011092:Polyethylene Glycols; D034741:RNA, Small Interfering; D015215:Zidovudine; C489540:Abcc4 protein, mouse
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