S4(13)-PV cell-penetrating peptide induces physical and morphological changes in membrane-mimetic lipid systems and cell membranes: Implications for cell internalization

• Published in: Biochimica et biophysica acta 2012-03, Vol.1818 (3), p.877-888
• Main Authors: Cardoso, Ana M.S., Trabulo, Sara, Cardoso, Ana L., Lorents, Annely, Morais, Catarina M., Gomes, Paula, Nunes, Cláudia, Lúcio, Marlene, Reis, Salette, Padari, Kärt, Pooga, Margus, Pedroso de Lima, Maria C., Jurado, Amália S.
• Format: Article
• Language: English
• Subjects: Cell Membrane - chemistry; Cell Membrane - metabolism; Cell Membrane - ultrastructure; Cell-penetrating peptide; Cell-Penetrating Peptides - chemistry; Cell-Penetrating Peptides - pharmacokinetics; Cell-Penetrating Peptides - pharmacology; Drug Delivery Systems - methods; DSC; Electron microscopy; Fluorescence polarization; HeLa Cells; Humans; Lipid Bilayers - chemistry; Lipid Bilayers - metabolism; Membrane model; Peptides - chemistry; Peptides - pharmacokinetics; Peptides - pharmacology; Phosphatidylethanolamines - chemistry; Phosphatidylethanolamines - metabolism; Phosphatidylglycerols - chemistry; Phosphatidylglycerols - metabolism; WAXS/SAXS
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2011.12.022

The present work aims to gain insights into the role of peptide–lipid interactions in the mechanisms of cellular internalization and endosomal escape of the S4(13)-PV cell-penetrating peptide, which has been successfully used in our laboratory as a nucleic acid delivery system. A S4(13)-PV analogue, S4(13)-PVscr, displaying a scrambled amino acid sequence, deficient cell internalization and drug delivery inability, was used in this study for comparative purposes. Differential scanning calorimetry, fluorescence polarization and X-ray diffraction at small and wide angles techniques showed that both peptides interacted with anionic membranes composed of phosphatidylglycerol or a mixture of this lipid with phosphatidylethanolamine, increasing the lipid order, shifting the phase transition to higher temperatures and raising the correlation length between the bilayers. However, S4(13)-PVscr, in contrast to the wild-type peptide, did not promote lipid domain segregation and induced the formation of an inverted hexagonal lipid phase instead of a cubic phase in the lipid systems assayed. Electron microscopy showed that, as opposed to S4(13)-PVscr, the wild-type peptide induced the formation of a non-lamellar organization in membranes of HeLa cells. We concluded that lateral phase separation and destabilization of membrane lamellar structure without compromising membrane integrity are on the basis of the lipid-driven and receptor-independent mechanism of cell entry of S4(13)-PV peptide. Overall, our results can contribute to a better understanding of the role of peptide–lipid interactions in the mechanisms of cell-penetrating peptide membrane translocation, helping in the future design of more efficient cell-penetrating peptide-based drug delivery systems. ► Cellular internalization of S413-PV peptide depends on membrane–lipid interactions. ► S413-PV and a scrambled analogue differently affect lipid physical behavior. ► S413-PV induces bilayer destabilization in lipid models and HeLa cell membranes. ► S413-PV uptake may be driven by lipid domain segregation and non-lamellar phases. ► Our data contribute to gain insights into peptide structure–activity relationships.