Synthetic Amphipathic β-Sheet Temporin-Derived Peptide with Dual Antibacterial and Anti-Inflammatory Activities

Abstract

Temporin family is one of the largest among antimicrobial peptides (AMPs), which act mainly by penetrating and disrupting the bacterial membranes. To further understand the relationship between the physical-chemical properties and their antimicrobial activity and selectivity, an analogue of Temporin L, [Nle1, DLeu9, DLys10]TL (Nle-Phe-Val-Pro-Trp-Phe-Lys-Phe-dLeu-dLys-Arg-Ile-Leu-CONH2) has been developed in the present work. The design strategy consisted of the addition of a norleucine residue at the N-terminus of the lead peptide sequence, [dLeu9, dLys10]TL, previously developed by our group. This modification promoted an increase of peptide hydrophobicity and, interestingly, more efficient activity against both Gram-positive and Gram-negative strains, without affecting human keratinocytes and red blood cells survival compared to the lead peptide. Thus, this novel compound was subjected to biophysical studies, which showed that the peptide [Nle1, dLeu9, dLys10]TL is unstructured in water, while it adopts β-type conformation in liposomes mimicking bacterial membranes, in contrast to its lead peptide forming α-helical aggregates. After its aggregation in the bacterial membrane, [Nle1, dLeu9, dLys10]TL induced membrane destabilization and deformation. In addition, the increase of peptide hydrophobicity did not cause a loss of anti-inflammatory activity of the peptide [Nle1, dLeu9, dLys10]TL in comparison with its lead peptide. In this study, our results demonstrated that positive net charge, optimum hydrophobic−hydrophilic balance, and chain length remain the most important parameters to be addressed while designing small cationic AMPs.

Glycosylation and Lipidation Strategies: Approaches for Improving Antimicrobial Peptide Efficacy

“…The main mechanism of action of AMPs is based on their interaction with the membrane of the pathogen [ 19 ]. Although the exact process is not yet fully defined, studies performed on model membranes (e.g., liposomes) have shown that the positive charge is responsible for the initial interaction with the negatively charged membrane of microorganisms, whereas the hydrophobic portion is responsible for their insertion into the lipid bilayer [ 20 ]. Consequently, achieving the right balance between the hydrophilic and hydrophobic domains is key in determining the specificity of action of AMPs [ 21 ].…”

Temporins: Multifunctional Peptides from Frog Skin

“…CD data suggest the formation of beta sheet structures in the presence of 1,2-dioleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DOPG)/cardiolipin (CL) and DOPG/1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) LUV. The increase in the hydrophobicity of the peptide due to the presence of NLe was related to an increased anti-inflammatory activity of the peptide in murine macrophage cell lines [ 99 ].…”

Peptidomic analysis of the host-defense peptides in skin secretions of the Amazon River frog Lithobates palmipes (Ranidae)

“…As well as showing possibilities for development into anti-infective agents for use against antibiotic-resistant and biofilmproducing microorganisms (Mangoni et al, 2016), temporin peptides have excited interest as a result of their anti-inflammatory (Zhang et al, 2021), antiviral (Marcocci et al, 2022), antiparasitic (André et al, 2020), wound healing (Di Grazia et al, 2014) and antidiabetic (Musale et al, 2018) properties. With the exception of the broad spectrum antimicrobial peptide temporin L (Bellavita et al, 2022), they display varying degrees of growth-inhibitory activity against Gram-positive bacteria and against the opportunistic yeast pathogens Candida spp. but are inactive against Gram-negative bacteria.…”