Interaction of a Polyarginine Peptide with Membranes of Different Mechanical Properties

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.

Internalization mechanisms of cell-penetrating peptides

“…The membrane deformations are thought to be caused by the charge neutralization, which can lead to a decrease in bending rigidity. A similar behavior was described for the TAT peptide by Herce et al, discussed in more detail in a previous section (Direct translocation mechanisms used by arginine-rich peptides), where the incorporation of water into the membrane together with the peptide as well as membrane thinning have been mentioned [47,48,123].…”

“…However, less is known about the influence of the plasma membrane properties on the uptake. The number of studies on this topic is rather narrow, however, information about the impact of plasma membrane composition and how it changes and adapts is available from studies using poly-arginines [123].…”

Regulation of the activity of an antimicrobial peptide by sterols or hopanoids: possible role in cell recognition

“…A previous study using P. aeruginosa (a hopanoid-lacking bacteria) has shown that cells preincubated with CHO or DP, exhibit decreased permeability and sensitivity to cell wall biosynthesis inhibitors, carbenicillin, and imipenem (Mangiarotti et al, 2019a). This behavior correlates with the changes induced by the presence of CHO or DP in the properties of artificial lipidic membranes.…”

“…The used optical trap equipment has been described previously (Crosio et al, 2019). Briefly, a 3W power ND:YVO4 laser (Spectra-Physics, Santa Clara, CA, USA) was focused through a 100x objective (water immersion, NA = 1, Zeiss).…”

“…It has been shown in pioneer works and recent publications that hopanoids can be considered sterol-surrogates in sterol-lacking bacteria. Biophysical studies, using artificial membranes, have demonstrated that hopanoids decrease the membrane permeability and increase the membrane order without compromising their mechanical properties (Sáenz et al, 2012, 2015; Mangiarotti et al, 2019a). In addition, and in accordance with in vitro studies, hopanoids promote resistance to antibiotics, detergents, extreme pHs, high temperature, oxidation, and high osmolarity in bacteria (Sáenz, 2010; Belin et al, 2018; Welander et al, 2010; Malott et al, 2014; Schmerk et al, 2011; Silipo et al, 2014; Kulkarni et al, 2013).…”