Dual functions of the human antimicrobial peptide LL-37-Target membrane perturbation and host cell cargo delivery
Artikel i vetenskaplig tidskrift, 2010

The mechanisms behind target vs. host cell recognition of the human antimicrobial peptide LL-37 remain ill-defined. Here, we have investigated the membrane disruption capacity of LL-37 using large unilamellar vesicles (LUVs) composed of varying mixtures of POPC, POPG and cholesterol to mimic target and host membranes respectively. We show that LL-37 is unable to induce leakage of entrapped calcein from zwitterionic POPC LUVs, whereas leakage from LUVs partially composed of POPG is fast and efficient. In accordance with typical antimicrobial peptide behavior, cholesterol diminished LL-37 induced leakage. By using linear dichroism and flow oriented LUVs, we found that LL-37 orients with the axis of its induced alpha-helix parallel to the membrane surface in POPC:POPG (7:3) LUVs. In the same system, we also observed a time-dependent increase of the parallel alpha-helix LD signal on timescales corresponding to the leakage kinetics. The increased LD may be connected to a peptide translocation step, giving rise to mass balance across the membrane. This could end the leakage process before it is complete, similar to what we have observed. Confocal microscopy studies of eukaryotic cells show that LL-37 is able to mediate the cell delivery of non-covalently linked fluorescent oligonucleotides, in agreement with earlier studies on delivery of plasmid DNA (Sandgren et al., J. Biol. Chem. 279 (2004) 17951). These observations highlight the potential dual functions of LL-37 as an antimicrobial agent against bacterial target cells and a cell-penetrating peptide that can deliver nucleic acids into the host cells.

defense

LL-37

CD

micelles

insight

LD

orientation

vesicles

Heparan sulphate

microscopy

Antimicrobial peptide

liposomes

ll-37

flow dichroism

Calcein leakage

human neutrophils

Confocal

antibacterial activity

Författare

X. A. Zhang

Peking University

Stockholms universitet

K. Oglecka

Stockholms universitet

Peking University

S. Sandgren

Lunds universitet

M. Belting

Lunds universitet

Elin Esbjörner Winters

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Bengt Nordén

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

A. Graslund

Stockholms universitet

Biochimica et Biophysica Acta - Biomembranes

0005-2736 (ISSN)

Vol. 1798 2201-2208

Styrkeområden

Nanovetenskap och nanoteknik

Livsvetenskaper och teknik

Ämneskategorier

Biokemi och molekylärbiologi

DOI

10.1016/j.bbamem.2009.12.011