Differential activity of lytic α-helical peptides on lactobacilli and lactobacilli-derived liposomes

SZYMANOWSKI, F.; BALATTI, G.E.; AMBROGGIO, E.; HUGO, A.A.; MARTINI, M.F.; FIDELIO, G.D.; GÓMEZ-ZAVAGLIA, A.; PICKHOLZ, M.; PÉREZ, P.F.

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES

ELSEVIER SCIENCE BV

Año: 2019 vol. 1861 p. 1069 - 1077

0005-2736

Eukaryotic antimicrobial peptides (AMPs) interact with plasma membrane of bacteria, fungi and eukaryoticparasites. Noteworthy, Lactobacillus delbrueckii subsp. lactis (CIDCA 133) and L. delbrueckii subsp. bulgaricus(CIDCA 331) show different susceptibility to human beta-defensins (β-sheet peptides). In the present work weextended the study to α-helical peptides from anuran amphibian (Aurein 1.2, Citropin 1.1 and Maculatin 1.1).We studied the effect on whole bacteria and liposomes formulated with bacterial lipids through growth kinetics,flow cytometry, leakage of liposome content and studies of peptide insertion in lipid monolayers.Growth of strain CIDCA 331 was dramatically inhibited in the presence of all three peptides and minimalinhibitory concentrations were lower than those for strain CIDCA 133. Flow cytometry revealed that AMPs leadto the permeabilization of bacteria.In addition, CIDCA 331-derived liposomes showed high susceptibility, leading to content leakage andstructural disruption. Accordingly, peptide insertion in lipid monolayers demonstrated spontaneous interactionof AMPs with CIDCA 331 lipids. In contrast, lipids monolayers from strain CIDCA 133 were less susceptible.Summarizing we demonstrate that the high resistance of the probiotic strain CIDCA 133 to AMPs extends to αhelix peptides Aurein, Citropin and Maculatin. This behavior could be ascribed in part to differences in membranecomposition. These findings, along with the previously demonstrated resistance to β defensins fromhuman origin, suggest that strain CIDCA 133 is well adapted to host innate immune effectors from bothmammals and amphibians thus indicating conserved mechanisms of interaction with key components of theinnate immune system.