title: pH-responsive PepFect cell-penetrating peptides.
abstract: A series of cell-penetrating PepFect peptide analogues was developed by substitutions of the galanin-derived N-terminal sequence. Histidine modifications were incorporated in order to make the peptides pH-responsive. The peptides were all able to form non-covalent complexes with an oligonucleotide cargo by co-incubation in buffer. The complexes were characterized by dynamic light scattering and circular dichroism, and an assay to evaluate the peptide-cargo affinity was developed. Cellular bioactivity was studied in HeLa cells using a luciferase-based splice correction assay. In addition, the membrane interactions of the peptides in large unilammelar vesicles was studied using a calcein leakage assay. The effects of substitutions were found to be dependent of the non-modified, C-terminal sequence of the peptides; for analogues of PepFect 3 we observed an increase in membrane activity and bioactivity for histidine-containing analogues, whereas the same modifications introduced to PepFect 14 lead to a decreased bioactivity. Peptides modified with a leucine/histidine sequence were found to be pH responsive, complexes formed from these peptides were small at pH 7 and grew under acidic conditions. The most promising of the novel PepFect 3 analogues, PepFect 132 has a significantly higher bioactivity and membrane activity than the parent peptide PepFect 3.
authors.affiliation: Department of Neurochemistry, the Arrhenius Laboratories for Natural Sciences, Stockholm University, Svante Arrhenius väg 16B, 106 91 Stockholm, Sweden. Electronic address: jakob@neurochem.su.se.
authors.forename: Jakob
authors.initials: J
authors.lastname: Regberg
authors.affiliation: Department of Neurochemistry, the Arrhenius Laboratories for Natural Sciences, Stockholm University, Svante Arrhenius väg 16B, 106 91 Stockholm, Sweden.
authors.forename: Luis
authors.initials: L
authors.lastname: Vasconcelos
authors.affiliation: Department of clinical Neuroscience (CNS), K8, CPF Karolinska Universitetssjukhuset Solna, 171 76 Stockholm, Sweden.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Madani
authors.affiliation: Department of Neurochemistry, the Arrhenius Laboratories for Natural Sciences, Stockholm University, Svante Arrhenius väg 16B, 106 91 Stockholm, Sweden; Laboratory of Molecular Biotechnology, Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia.
authors.forename: Ülo
authors.initials: Ü
authors.lastname: Langel
authors.affiliation: Department of Neurochemistry, the Arrhenius Laboratories for Natural Sciences, Stockholm University, Svante Arrhenius väg 16B, 106 91 Stockholm, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Hällbrink
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D057846:Cell-Penetrating Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D002942:Circular Dichroism; D006367:HeLa Cells; D006639:Histidine / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D055666:Lipopeptides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D009841:Oligonucleotides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology
chemical_list: D057846:Cell-Penetrating Peptides; D055666:Lipopeptides; D009841:Oligonucleotides; D006639:Histidine
keywords: Calcein leakage; Cell-penetrating peptide; Cellular uptake; Oligonucleotide delivery; PepFect; pH-responsive