title: Interaction of nucleic acids with the glycocalyx.
abstract: Mammalian cells resist the uptake of nucleic acids. The lipid bilayer of the plasma membrane presents one barrier. Here, we report on a second physicochemical barrier for uptake. To create a sensitive probe for nucleic acid-cell interactions, we synthesized fluorescent conjugates in which lipids are linked to DNA oligonucleotides. We found that these conjugates incorporate readily into the plasma membrane but are not retained there. Expulsion of lipid-oligonucleotide conjugates from the plasma membrane increases with oligonucleotide length. Conversely, the incorporation of conjugates increases markedly in cells that lack the major anionic components of the glycocalyx, sialic acid and glycosaminoglycans, and in cells that had incorporated highly cationic lipids into their plasma membrane. We conclude that anionic oligosaccharides provide a formidable barrier to the uptake of nucleic acids by mammalian cells. This conclusion has implications for genomic stability, as well as the delivery of genes and siRNAs into mammalian cells.
authors.affiliation: Medical Scientist Training Program, Molecular & Cellular Pharmacology Graduate Training Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Palte
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Raines
mesh_terms: D000818:Animals; D000838:Anions; D002412:Cations; D004247:DNA / Q000737:chemistry; D019276:Glycocalyx / Q000737:chemistry*; D006025:Glycosaminoglycans / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D019158:N-Acetylneuraminic Acid / Q000737:chemistry; D009696:Nucleic Acids / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D000838:Anions; D002412:Cations; D006025:Glycosaminoglycans; D008051:Lipid Bilayers; D008055:Lipids; D009696:Nucleic Acids; D009841:Oligonucleotides; D009844:Oligosaccharides; D034741:RNA, Small Interfering; D004247:DNA; D019158:N-Acetylneuraminic Acid