title: A new peptide motif present in the protective antigen of anthrax toxin exerts its efficiency on the cellular uptake of liposomes and applications for a dual-ligand system.
abstract: Protective antigen (PA) is a nontoxic protein present in anthrax toxin. Domain 4 of PA (PA-D4) acts as a receptor binding site for tumor endothelial marker 8 (TEM8). In this study, KYND motif from PA-D4 was utilized as a ligand against TEM8. The efficiency of KYND motif on cellular association was assessed by evaluating the cellular uptake of PEGylated liposomes (PEG-LPs) in TEM8 positive and negative cells. The peptide was attached on the top of the PEG of PEG-LP. Compared to PEG-LP, KYND modified PEG-LP (KYND-PEG-LP) enhanced the cellular uptake to a greater extent in all cell lines. Based on the inhibition assay, no receptor involvement was observed in the cellular association of KYND-PEG-LP, suggesting that KYND motif functions as a cell penetrating peptide (CPP) which facilitated the internalization of PEG-LP via clathrin mediated endocytosis pathway. Further enhancement of cellular uptake was observed when KYND-PEG-LP was combined with octaarginine (R8) on the surface of lipid membrane as dual-CPP ligand formulation, however, when PEG-LP combined with only R8, only negligible enhancement was observed. These findings suggest that two CPP ligands act in a synergistic fashion; therefore the dual-CPP ligand based liposomal formulation can be assumed to be an effective delivery system.
authors.affiliation: Laboratory of Innovative Nanomedicine, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Golam
authors.initials: G
authors.lastname: Kibria
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatakeyama
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Harashima
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry*; D001667:Binding, Competitive; D001692:Biological Transport; D014408:Biomarkers, Tumor / Q000378:metabolism; D002460:Cell Line; D057846:Cell-Penetrating Peptides / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D004337:Drug Carriers / Q000378:metabolism*; D016503:Drug Delivery Systems / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D008081:Liposomes; D051379:Mice; D008840:Microfilament Proteins; D009363:Neoplasm Proteins / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D018000:Receptors, Peptide / Q000378:metabolism
chemical_list: C473287:ANTXR1 protein, human; D000942:Antigens, Bacterial; C523012:Antxr1 protein, mouse; D001427:Bacterial Toxins; D014408:Biomarkers, Tumor; D057846:Cell-Penetrating Peptides; D004337:Drug Carriers; D008024:Ligands; D008081:Liposomes; D008840:Microfilament Proteins; D009363:Neoplasm Proteins; D009842:Oligopeptides; D010446:Peptide Fragments; D010714:Phosphatidylethanolamines; D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; C030325:anthrax toxin; C448619:octaarginine; C038089:1,2-distearoylphosphatidylethanolamine; D011092:Polyethylene Glycols