title: A gene delivery approach for antimicrobials: expression of defensins.
abstract: BACKGROUND
  Peptide antibiotics as new therapeutic agents are becoming a popular option to investigate due to their broad bacterial target selectivity and limited resistance problems. Although attractive, these new drug candidates have several limitations including low potency and delivery issues which face all peptides/proteins.
  
  
  METHODS
  In this study, we designed a plasmid expression system for human beta defensin 3. This sequence was cloned from a human epithelial lung cell into a CMV driven expression cassette. This expression plasmid was then evaluated for its ability to produce human-beta defensin 3 with the use of the non-viral transfection agent, polyethylenimine (PEI).
  
  
  RESULTS
  The results indicate the expression cassette was transcriptionally active in HEK 293 cells, as measured by RT-PCR and that a beta defensin peptide was produced by the cells as confirmed by Western blot. The biological activity of the peptide was confirmed against both gram negative E. coli and gram positive Bacillus species using in vitro screening.
  
  
  CONCLUSIONS
  Both the cultured media as well as the transfected cell lysate demonstrated biological activity demonstrating the peptide is also secreted.
authors.affiliation: Department of Pharmaceutics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Preeti
authors.initials: P
authors.lastname: Yadava
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hughes
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D003470:Culture Media; D023082:Defensins / Q000096:biosynthesis* / Q000494:pharmacology*; D016503:Drug Delivery Systems; D004591:Electrophoresis, Polyacrylamide Gel; D004847:Epithelial Cells / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects; D005079:Excipients; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D011094:Polyethyleneimine; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D023083:beta-Defensins / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; C422950:DEFB103A protein, human; D023082:Defensins; D005079:Excipients; D023083:beta-Defensins; D011094:Polyethyleneimine