Transgene delivery with a cationic lipid in the presence of amyloid beta (beta AP) peptide

The ability of a cationic lipid to deliver plasmid DNA (pDNA) in presence o f the neurotoxic fragment of amyloid beta -peptide was evaluated. Pre-treat ment of cells with beta AP (25-35) peptide resulted in a modest increase in transgene expression. When beta AP (25-35) peptide was mixed with the pDNA /liposome complex and used, the complexes lost their ability to transfect. However, the reverse sequenced beta AP (35-25) peptide demonstrated no sign ificant differences in transgene expression in pre-treated cells, and in ce lls where PAP (35-25) peptide was mixed with pDNA/liposome complexes and tr ansfected. The amount of pDNA delivered to the cells was decreased in prese nce of beta AP (25-35) as measured with flow cytometry using fluorescently labeled liposomes. The decreased endocytosis may be due to their rod-like s tructure formation as demonstrated by electron microscopy and atomic force microscopy (AFM). These results demonstrate that beta AP (25-35) peptide ma y interfere with gene delivery with cationic systems.