title: A synthetic peptide containing loop 4 of nerve growth factor for targeted gene delivery.
abstract: BACKGROUND
  Gene delivery vectors that restrict the expression of a therapeutic gene to a particular type of cells are critical to gene therapy in a complex structure, such as the central nervous system. We constructed a nonviral vector for targeted gene transfer to cells expressing nerve growth factor (NGF) receptor TrkA.
  
  
  RESULTS
  The vector was a synthetic chimeric peptide composed of a targeting moiety derived from NGF loop 4 and a DNA-binding moiety of 10 lysine residues. The peptide activated signal transduction pathways of the NGF receptor TrkA in PC12 cells and supported the survival of the cells after serum deprivation. After forming complexes with plasmid DNA, the peptide dose-dependently increased reporter gene expression in PC12 cells, which could be inhibited by excess NGF. The peptide-mediated gene expression was not affected in PC12 cells by co-incubation with a blocking antibody against the low-affinity NGF receptor p75 and was significantly enhanced in NIH3T3 cells stably transfected with TrkA cDNA, suggesting the involvement of the high-affinity NGF receptor TrkA without the participation of p75. Moreover, the peptide did not assist gene transfer in TrkA-poor, but TrkB- and/or TrkC-positive primary cerebellar granule neurons and primary cortical glial cells.
  
  
  CONCLUSIONS
  The chimeric peptide reported will be useful in gene delivery to and gene therapy of the nervous system and other tissues/organs with cells expressing TrkA.
authors.affiliation: Institute of Bioengineering and Nanotechnology, Singapore.
authors.forename: Jieming
authors.initials: J
authors.lastname: Zeng
authors.forename: Heng-Phon
authors.initials: HP
authors.lastname: Too
authors.forename: Yuexia
authors.initials: Y
authors.lastname: Ma
authors.forename: Elizabeth S E
authors.initials: ES
authors.lastname: Luo
authors.forename: Shu
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D002470:Cell Survival; D002531:Cerebellum / Q000166:cytology; D002540:Cerebral Cortex / Q000166:cytology; D016895:Culture Media, Serum-Free; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D051379:Mice; D041681:NIH 3T3 Cells; D020932:Nerve Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D016716:PC12 Cells; D010455:Peptides / Q000138:chemical synthesis / Q000235:genetics*; D051381:Rats; D020917:Receptor, trkA / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction
chemical_list: D016895:Culture Media, Serum-Free; D010455:Peptides; D020932:Nerve Growth Factor; D020917:Receptor, trkA