Broad-Spectrum Antiviral Activity of the Amphibian Antimicrobial Peptide Temporin L and Its Analogs

Abstract

The COVID-19 pandemic has evidenced the urgent need for the discovery of broad-spectrum antiviral therapies that could be deployed in the case of future emergence of novel viral threats, as well as to back up current therapeutic options in the case of drug resistance development. Most current antivirals are directed to inhibit specific viruses since these therapeutic molecules are designed to act on a specific viral target with the objective of interfering with a precise step in the replication cycle. Therefore, antimicrobial peptides (AMPs) have been identified as promising antiviral agents that could help to overcome this limitation and provide compounds able to act on more than a single viral family. We evaluated the antiviral activity of an amphibian peptide known for its strong antimicrobial activity against both Gram-positive and Gram-negative bacteria, namely Temporin L (TL). Previous studies have revealed that TL is endowed with widespread antimicrobial activity and possesses marked haemolytic activity. Therefore, we analyzed TL and a previously identified TL derivative (Pro3, DLeu9 TL, where glutamine at position 3 is replaced with proline, and the D-Leucine enantiomer is present at position 9) as well as its analogs, for their activity against a wide panel of viruses comprising enveloped, naked, DNA and RNA viruses. We report significant inhibition activity against herpesviruses, paramyxoviruses, influenza virus and coronaviruses, including SARS-CoV-2. Moreover, we further modified our best candidate by lipidation and demonstrated a highly reduced cytotoxicity with improved antiviral effect. Our results show a potent and selective antiviral activity of TL peptides, indicating that the novel lipidated temporin-based antiviral agents could prove to be useful additions to current drugs in combatting rising drug resistance and epidemic/pandemic emergencies.

Design of Three Residues Peptides against SARS-CoV-2 Infection

“…Several antimicrobial peptides (AMPs) have also been tested for their anti-SARS-CoV-2 activity. Recently, we described the broad-spectrum antiviral potential of the amphibian AMP temporin L and its analogs [ 36 ]. Temporin L has been tested against a wide panel of enveloped and naked DNA and RNA viruses, including SARS-CoV-2, and its effect is specifically addressed to early stages of viral infection.…”

“…To understand whether the tripeptides were able to inhibit coronavirus infectivity and, specifically, their mode of action, four different assays were performed. The difference between the four schemes of treatment is the timing of the addition of tripeptides [ 36 ]. Co-treatment test.…”

The Inhibition of DNA Viruses by the Amphibian Antimicrobial Peptide Temporin G: A Virological Study Addressing HSV-1 and JPCyV

“…Subsequently, to verify the possible antiviral activity of TG against HSV-1, a time-ofaddition assay was performed by focusing on two specific phases of the virus life cycle: the virus attachment/entry into the host cell and the subsequent replication phase into the host cell. For this purpose, Vero cells were infected with 1 multiplicity of infection (MOI) of HSV-1, and increasing concentrations of TG (10,20,40,50,70, and 100 µg/mL) were administered only during the virus adsorption phase (for 1 h; ADS) or immediately after (and left for 20 h; POST). Untreated HSV-1-infected Vero cells were used under the same conditions as a comparative control.…”

“…We previously reported the antiviral efficacy of the isoform temporin B (TB) in an in vitro model of herpes simplex virus type 1 (HSV-1) infection where TB was found to disrupt the viral envelope [8]. More recently, we demonstrated that other members of the temporin family affect the life cycle of some enveloped RNA viruses, such as influenza A virus, parainfluenza virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while in some cases, they also alter the integrity of the virions [9,10]. These data suggest the potential of these peptides to display a broad spectrum of antiviral activity that deserves further investigation.…”

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

“…We have particularly focused on Temporin L (TL, FVQWFSKFLGRIL), one of the most potent temporin isoforms but also the most highly hemolytic [ 35 ]. Indeed, our previous attempts were aimed at improving its biological profile through the application of several synthetic strategies, including proline decoration [ 36 ], lipidation, and side chain-to-side chain cyclizations [ 37 , 38 , 39 , 40 ]. Several TL analogues were developed and characterized through biophysical techniques to elucidate their mode of action, some of them also displayed a wide broad-spectrum antibacterial activity and no cytotoxicity on human cells.…”