Autor(es):
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 ; Lima, Maria C. Pedroso de ; Jurado, Amália S.
Data: 2012
Identificador Persistente: http://hdl.handle.net/10316/19932
Origem: Estudo Geral - Universidade de Coimbra
Assunto(s): Cell-penetrating peptide; Membrane model; DSC; Fluorescence polarization; WAXS/SAXS; Electron microscopy
Descrição
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.
