Interaction of a Polyarginine Peptide with Membranes of Different Mechanical Properties.

Matías A Crosio,Agustin Mangiarotti,Mario G Del Pópolo,Matías A Via,Candelaria I Cámara,Natalia Wilke

doi:10.3390/biom9100625

Abstract

The membrane translocation efficiency of cell penetrating peptides (CPPs) has been largely studied, and poly-arginines have been highlighted as particularly active CPPs, especially upon negatively charged membranes. Here we inquire about the influence of membrane mechanical properties in poly-arginine adsorption, penetration and translocation, as well as the subsequent effect on the host membrane. For this, we selected anionic membranes exhibiting different rigidity and fluidity, and exposed them to the nona-arginine KR9C. Three different membrane compositions were investigated, all of them having 50% of the anionic lipid 1,2-dioleoyl-sn-glycero-3-phospho-(1’-rac-glycerol) (DOPG), thus, ensuring a high affinity of the peptide for membrane surfaces. The remaining 50% was a saturated PC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC), an unsaturated PC (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC) or a mixture of DOPC with cholesterol. Peptide-membrane interactions were studied using four complementary models for membranes: Langmuir monolayers, Large Unilamellar Vesicles, Black Lipid Membranes and Giant Unilamellar Vesicles. The patterns of interaction of KR9C varied within the different membrane compositions. The peptide strongly adsorbed on membranes with cholesterol, but did not incorporate or translocate them. KR9C stabilized phase segregation in DPPC/DOPG films and promoted vesicle rupture. DOPC/DOPG appeared like the better host for peptide translocation: KR9C adsorbed, inserted and translocated these membranes without breaking them, despite softening was observed.

Highlights

Cellular membranes regulate lateral diffusion of the lipids and proteins associated to them, compartmentalization and permeability
With the aim of studying the interaction of cell penetrating peptides (CPPs) with membranes of different mechanical With the aim of studying the interaction of CPPs with membranes of different mechanical properties, we studied the incorporation of KR9C into monolayers that contained DOPG and DOPC, properties, we studied the incorporation of KR9 C into monolayers that contained DOPG and DPPC or DOPC/CHOL
Considering the results reported in the literature and our own ones, the difference in the values of k between both compositions can be explained considering that the peptide penetrated into the DOPC/DOPG Giant Unilamellar Vesicles (GUVs), whilst it did not cross the membranes with CHOL

Summary

Introduction

Cellular membranes regulate lateral diffusion of the lipids and proteins associated to them, compartmentalization and permeability. It has been shown that organisms adapt the lipid composition of their membranes in order to maintain them mainly in a fluid state [1]. Biomolecules 2019, 9, 625 compositions, which leads to local differences in mechanical properties. The current model for membranes is a patchwork-like surface, with the different regions being highly variable both, in size and in time [3]. Soluble molecules that interact with membranes, such as peptides may have affinities that depend on membrane composition and rheology. As a consequence of the patchwork-like character of the membrane, regions with a broad spectrum of properties are available for the interaction with soluble peptides. It is important to know to what extent the peptide-membrane interactions depend on membrane rheology, and how the membrane mechanical properties change after the interaction has taken place

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