Antibacterial and cell penetrating effects of LFcin17–30, LFampin265–284, and LF chimera on enteroaggregative Escherichia coli

Abstract

Lactoferrin (LF) is a protein with antimicrobial activity, which is conferred in part by 2 regions contained in its N-terminal lobe. These regions have been used to develop the following synthetic peptides: lactoferricin17–30, lactoferrampin265–284, and LF chimera (a fusion of lactoferricin17–30 and lactoferrampin265–284). We have reported that these LF peptides have antibacterial activity against several pathogenic bacteria; however, the exact mechanism of action has not been established. Here, we report the effects of LF peptides on the viability of enteroaggregative Escherichia coli (EAEC) and the ability of these peptides to penetrate into the bacteria cytoplasm. The viability of EAEC treated with LF peptides was determined via enumeration of colony-forming units, and the binding and internalization of the LF peptides was followed via immunogold labeling and electron microscopy. Treatment of EAEC with 20 and 40 μmol/L LF peptides reduced bacterial growth compared with untreated bacteria. Initially the peptides associated with the plasma membrane, but after 5 to 30 min of incubation, the peptides were found in the cytoplasm. Remarkably, bacteria treated with LF chimera developed cytosolic electron-dense structures that contained the antimicrobial peptide. Our results suggest that the antibacterial mechanism of LF peptides on EAEC involves their interaction with and penetration into the bacteria.

Antibacterial Activity of cLFchimera and its Synergistic Potential with Antibiotics against Some Foodborne Pathogens Bacteria

“…Moreover, the results of SEM analysis showed that cLFchimera had no visible damaging effect on the outer layer of the bacteria, suggesting that maybe a molecular-level mechanism plays an important role in the synergistic action of cLFchimera. In this regards, Reyes-Cortes et al, (2017) showed that this chimeric peptide mediated its antibacterial activity by entering the cytoplasm through translocation across the bacterial membrane and possibly interacting with internal organelles [33]. Consistent with these results, Pirkhezranian et al, (2020 a, b) using molecular simulation analysis showed that cLFchimera and its derivatives had a higher a nity for DNA interaction and hypothesized this chimeric peptide mediated its activity by intramolecular mechanisms which interference DNA related pathways such as DNA replication [34,35].…”

Interaction of camel Lactoferrin derived peptides with DNA: a molecular dynamics study

“…Although the intracellular activity of Lactoferrin derived peptides has been previously demonstrated [ 8], the exact mechanism of action has not been yet established. As recognition of specific DNA sequences by proteins is highly complex, involving structural, energetic and dynamic aspects, the interaction cannot be easily characterized at the atomic level by experimental approaches alone [ 16].…”

“…We have recently reported that a camel Lactoferrin chimera (CLFchimera) resulting from the fusion of the C-terminal ends of camel Lactoferricin 17-30 (CLFcin) and camel Lactoferrampin 265-284 (CLFampin) using the side chain of lysine as linker to the second peptide, has a broad-spectrum activity against both Gram-positive and Gram-negative bacteria [ 6,7]. Furthermore, Reyes-Cortes et al (2016) showed that this chimeric peptide mediated its antibacterial activity by entering the cytoplasm and possibly interacting with internal organelles [ 8]. To date, there has been no precise explanation for the mechanisms underlying the antimicrobial peptide function, but it is known that DNA is one of the most important intracellular targets for AMPs [ 9].…”

Exploiting Lactoferricin (17–30) as a Potential Antimicrobial and Antibiofilm Candidate Against Multi-Drug-Resistant Enteroaggregative Escherichia coli

“…Lfcin (17-30) has been identified to act against bacteria, fungi, amoeba, stimulants of bio-warfare agents, and even bacterial biofilms (van der Kraan et al, 2005;Xu et al, 2010;Sijbrandij et al, 2017;Acosta-Smith et al, 2018;Díaz-Godínez et al, 2019). Nevertheless, its use against MDR pathogens, such as EAEC, remains unrevealed, barring a few systematic studies against pathogens like Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii (Reyes-Cortes et al, 2016;Pollini et al, 2017). Even studies addressing the antimicrobial and antibiofilm potential of Lfcin (17-30) against MDR-EAEC are lacking.…”