scholarly journals Temperature-, concentration- and cholesterol-dependent translocation of L- and D-octa-arginine across the plasma and nuclear membrane of CD34+ leukaemia cells

2007 ◽  
Vol 403 (2) ◽  
pp. 335-342 ◽  
Author(s):  
Marjan M. Fretz ◽  
Neal A. Penning ◽  
Saly Al-Taei ◽  
Shiroh Futaki ◽  
Toshihide Takeuchi ◽  
...  

Delineating the mechanisms by which cell-penetrating peptides, such as HIV-Tat peptide, oligoarginines and penetratin, gain access to cells has recently received intense scrutiny. Heightened interest in these entities stems from their ability to enhance cellular delivery of associated macromolecules, such as genes and proteins, suggesting that they may have widespread applications as drug-delivery vectors. Proposed uptake mechanisms include energy-independent plasma membrane translocation and energy-dependent vesicular uptake and internalization through endocytic pathways. In the present study, we investigated the effects of temperature, peptide concentration and plasma membrane cholesterol levels on the uptake of a model cell-penetrating peptide, L-octa-arginine (L-R8) and its D-enantiomer (D-R8) in CD34+ leukaemia cells. We found that, at 4–12 °C, L-R8 uniformly labels the cytoplasm and nucleus, but in cells incubated with D-R8 there is additional labelling of the nucleolus which is still prominent at 30 °C incubations. At temperatures between 12 and 30 °C, the peptides are also localized to endocytic vesicles which consequently appear as the only labelled structures in cells incubated at 37 °C. Small increases in the extracellular peptide concentration in 37 °C incubations result in a dramatic increase in the fraction of the peptide that is localized to the cytosol and promoted the binding of D-R8 to the nucleolus. Enhanced labelling of the cytosol, nucleus and nucleolus was also achieved by extraction of plasma membrane cholesterol with methyl-β-cyclodextrin. The data argue for two, temperature-dependent, uptake mechanism for these peptides and for the existence of a threshold concentration for endocytic uptake that when exceeded promotes direct translocation across the plasma membrane.

2016 ◽  
Vol 31 (3) ◽  
pp. 975-988 ◽  
Author(s):  
Carmen Juks ◽  
Annely Lorents ◽  
Piret Arukuusk ◽  
Ülo Langel ◽  
Margus Pooga

2009 ◽  
Vol 420 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Catherine L. Watkins ◽  
Dirk Schmaljohann ◽  
Shiroh Futaki ◽  
Arwyn T. Jones

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 μM 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 °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-β-cyclodextrin enhanced translocation of octa-arginine across the plasma membrane of suspension cells at 37 °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 °C in KG1a cells, but this effect could be reversed by re-addition of cholesterol as methyl-β-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.


2001 ◽  
Vol 42 (9) ◽  
pp. 1492-1500 ◽  
Author(s):  
Howard S. Kruth ◽  
Ina Ifrim ◽  
Janet Chang ◽  
Lia Addadi ◽  
Daniele Perl-Treves ◽  
...  

2009 ◽  
Vol 33 (10) ◽  
pp. 1079-1086 ◽  
Author(s):  
Nadezhda Stefanova ◽  
Galya Staneva ◽  
Diana Petkova ◽  
Teodora Lupanova ◽  
Roumen Pankov ◽  
...  

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