title: A needle-and-thread approach to bilayer transport: permeation of a molecular umbrella-oligonucleotide conjugate across a phospholipid membrane.
abstract: A di-walled molecular umbrella, composed of two choloyl groups, one spermidine moiety, and a 5-thiol(2-nitrobenzoyl) "handle", was covalently attached to a 16-mer oligonucleotide (S-dT16) through a disulfide bond. Incubation of this conjugate (1) with vesicles made from 1-palmitoyl-2-oleyol-sn-glycero-3-phosphocholine and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (95/5, mol/mol) (200 nm diameter, extrusion) that contained entrapped glutathione (GSH) at 37 degrees C resulted in the liberation of the oligonucleotide and the umbrella-bound 5-mercapto(2-nitrobenzoyl) moiety (USH) via thiolate-disulfide interchange. The appearance of USH, together with the absence of leakage of entrapped GSH and a vesicular capture of the oligonucleotide that matches the extent of USH formation, provides compelling evidence for delivery of S-dT16 into the aqueous compartment of these vesicles. In a sense, the molecular umbrella functions like a "needle" in providing a pathway for the oligonucleotide (the "thread") to cross the membrane.
authors.affiliation: Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
authors.forename: Vaclav
authors.initials: V
authors.lastname: Janout
authors.forename: Steven L
authors.initials: SL
authors.lastname: Regen
mesh_terms: D002463:Cell Membrane Permeability; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009841:Oligonucleotides / Q000737:chemistry / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism*; D010715:Phosphatidylglycerols / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004220:Disulfides; D004337:Drug Carriers; D008051:Lipid Bilayers; D009841:Oligonucleotides; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D005978:Glutathione; C028694:1-palmitoyl-2-oleoylphosphatidylcholine