Insight into the mechanism of action of temporin-SHa, a new broad-spectrum antiparasitic and antibacterial agent.
Antimicrobial peptides (AMPs) are promising drugs to kill resistant pathogens. In contrast to bacteria, protozoan parasites, such as Leishmania, were little studied. Therefore, the antiparasitic mechanism of AMPs is still unclear. In this study, we sought to get further insight into this mechanism by focusing our attention on temporin-SHa (SHa), a small broad-spectrum AMP previously shown to be active against Leishmania infantum. To improve activity, we designed analogs of SHa and compared the antibacterial and antiparasitic mechanisms. [K3]SHa emerged as a highly potent compound active against a wide range of bacteria, yeasts/fungi, and trypanosomatids (Leishmania and Trypanosoma), with leishmanicidal intramacrophagic activity and efficiency toward antibiotic-resistant strains of S. aureus and antimony-resistant L. infantum. Multipassage resistance selection demonstrated that temporins-SH, particularly [K3]SHa, are not prone to induce resistance in Escherichia coli. Analysis of the mode of action revealed that bacterial and parasite killing occur through a similar membranolytic mechanism involving rapid membrane permeabilization and depolarization. This was confirmed by high-resolution imaging (atomic force microscopy and field emission gun-scanning electron microscopy). Multiple combined techniques (nuclear magnetic resonance, surface plasmon resonance, differential scanning calorimetry) allowed us to detail peptide-membrane interactions. [K3]SHa was shown to interact selectively with anionic model membranes with a 4-fold higher affinity (KD = 3 x 10-8 M) than SHa. The amphipathic α-helical peptide inserts in-plane in the hydrophobic lipid bilayer and disrupts the acyl chain packing via a detergent-like effect. Interestingly, cellular events, such as mitochondrial membrane depolarization or DNA fragmentation, were observed in L. infantum promastigotes after exposure to SHa and [K3]SHa at concentrations above IC50. Our results indicate that these temporins exert leishmanicidal activity via a primary membranolytic mechanism but can also trigger apoptotis-like death. The many assets demonstrated for [K3]SHa make this small analog an attractive template to develop new antibacterial/antiparasitic drugs.
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), Biogenèse des Signaux Peptidiques (BIOSIPE), Paris, France.
Zahid
Z
Raja
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), Biogenèse des Signaux Peptidiques (BIOSIPE), Paris, France.
Sonia
S
André
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), Biogenèse des Signaux Peptidiques (BIOSIPE), Paris, France.
Feten
F
Abbassi
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface (LRS), Paris, France.
Vincent
V
Humblot
Sorbonne Universités, UPMC Univ Paris 06, Ecole Normale Supérieure, CNRS, Laboratoire des Biomolécules, Paris, France.|Department of Chemistry, Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Laboratoire des Biomolécules, Paris, France.
Olivier
http://orcid.org/0000-0001-5307-3068
O
Lequin
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), Plate-forme Interactions Moléculaires, Paris, France.
Tahar
T
Bouceba
Sorbonne Universités, UPMC Univ Paris 06, Ecole Normale Supérieure, CNRS, Laboratoire des Biomolécules, Paris, France.|Department of Chemistry, Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Laboratoire des Biomolécules, Paris, France.
Isabelle
I
Correia
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface (LRS), Paris, France.
Sandra
S
Casale
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), Biogenèse des Signaux Peptidiques (BIOSIPE), Paris, France.
Thierry
T
Foulon
Institut de Recherche pour le Développement (IRD), UMR 224 IRD-CNRS-Univ Montpellier 1 et 2 Maladies infectieuses et Vecteurs: écologie, génétique, évolution et contrôle (MiVegec), Montpellier, France.|IRD, UMR 177 IRD-CIRAD, Interactions Hôtes-Vecteurs-Parasites-Environnement dans les maladies tropicales négligées dues aux Trypanosomatidae (InterTryp), Montpellier, France.
Denis
D
Sereno
Institut de Recherche pour le Développement (IRD), UMR 224 IRD-CNRS-Univ Montpellier 1 et 2 Maladies infectieuses et Vecteurs: écologie, génétique, évolution et contrôle (MiVegec), Montpellier, France.|IRD, UMR 177 IRD-CIRAD, Interactions Hôtes-Vecteurs-Parasites-Environnement dans les maladies tropicales négligées dues aux Trypanosomatidae (InterTryp), Montpellier, France.
Bruno
B
Oury
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), Biogenèse des Signaux Peptidiques (BIOSIPE), Paris, France.
Ali
A
Ladram
D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000633:toxicity; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000633:toxicity; D000981:Antiprotozoal Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D016054:DNA, Protozoan / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D024881:Drug Resistance, Bacterial; D006801:Humans; D007891:Leishmania / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D013997:Time Factors; D014345:Trypanosoma / Q000187:drug effects; D053835:Unilamellar Liposomes / Q000737:chemistry
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D000981:Antiprotozoal Agents; D016054:DNA, Protozoan; D053835:Unilamellar Liposomes; C000595450:temporin-SHa peptide, Pelophylax saharica; D000667:Ampicillin