Low concentration thresholds of plasma membranes for rapid energy-independent translocation of a cell-penetrating peptide

Watkins, Catherine Louise, Schmaljohann, Dirk, Futaki, Shiroh and Jones, Arwyn Tomos ORCID: https://orcid.org/0000-0003-2781-8905 2009. Low concentration thresholds of plasma membranes for rapid energy-independent translocation of a cell-penetrating peptide. Biochemical Journal 420 (2) , pp. 179-189. 10.1042/BJ20090042

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Abstract

The exact mechanisms by which cell-penetrating peptides such as oligo-arginines and penetratin cross biological membranes has yet to be elucidated, but this is required if they are to reach their full potential as cellular delivery vectors. In the present study, qualitative and quantitative analysis of the influence of temperature, peptide concentration and plasma membrane cholesterol on the uptake and subcellular distribution of the model cell-penetrating peptide octa-arginine was performed in a number of suspension and adherent cell lines. When experiments were performed on ice, the peptide at 2 microM extracellular concentration efficiently entered and uniformly labelled the cytoplasm of all the suspension cells studied, but a 10-fold higher concentration was required to observe similar results in adherent cells. At 37 degrees C and at higher peptide concentrations, time-lapse microscopy experiments showed that the peptide rapidly penetrated the entire plasma membrane of suspension cells, with no evidence of a requirement for nucleation zones to promote this effect. Cholesterol depletion with methyl-beta-cyclodextrin enhanced translocation of octa-arginine across the plasma membrane of suspension cells at 37 degrees C, but decreased overall peptide accumulation. Under the same conditions in adherent cells this agent had no effect on peptide uptake or distribution. Cholesterol depletion increased the overall accumulation of the peptide at 4 degrees C in KG1a cells, but this effect could be reversed by re-addition of cholesterol as methyl-beta-cyclodextrin-cholesterol complexes. The results highlight the relatively high porosity of the plasma membrane of suspension cells to this peptide, especially at low temperatures, suggesting that this feature could be exploited for delivering bioactive entities.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Pharmacy
Subjects:	R Medicine > RS Pharmacy and materia medica
Publisher:	Biochemical Society
ISSN:	0264-6021
Last Modified:	18 Oct 2022 12:23
URI:	https://orca.cardiff.ac.uk/id/eprint/9645

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