Antimicrobial peptides from marine animals: Sources, structures, mechanisms and the potential for drug development

Abstract

The emergence of antibiotic-resistant bacteria has become a major challenge in current clinical treatment. As essential natural molecules involved in innate immunity, antimicrobial peptides (AMPs) have the potential to break the limits of antibiotic resistance. While AMPs are widely presented in various organisms on this planet, the marine environment is unique in generating a large number of AMPs that exhibit characteristic structures and functions. This review summarizes the structures and mechanisms of action of AMPs derived from invertebrates, fish, amphibians, reptiles, and mammals in the ocean. The comparison of AMPs from organisms in different habitats demonstrates the preference of Arg (arginine) and Leu (leucine) in marine AMPs, which might be associated with the adaptation to the unique features of bacterial membranes in marine environments. In addition, the potential and applications of marine AMPs for the development of novel antibiotics are also described. These summaries are expected to provide a reference for the development and utilization of marine resources in drug development or aquiculture.

Aquiluscidin, a Cathelicidin from Crotalus aquilus, and the Vcn-23 Derivative Peptide, Have Anti-Microbial Activity against Gram-Negative and Gram-Positive Bacteria

“…The results obtained in the cytotoxicity assay are consistent with those previously published when evaluating the cytotoxic activity of different cathelicidins and their derived peptides against various cell lines. Such is the case of crotalicidin (Ctn), which exhibited strong cytotoxic activity against fibroblasts (IBR3G), with an LD 50 of only 6.25 µM, while its derivatives Ctn [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and Ctn [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] were practically non-toxic at the highest evaluated concentration, i.e., 100 µM [18]. The potential cytotoxicity of the same cathelicidin and its two fragments against human kidney cells (HK-2) resulted in a lower effect by Ctn [1][2][3][4][5][6][7][8][9][10]…”

“…They can exert their activity by directly killing microorganisms or by carrying out actions that stimulate the host's immune responses [5,6]. Among the microbicidal mechanisms of action of AMPs are membrane disruption, prevention of cell wall formation, and inhibition of protein synthesis and folding [5][6][7]. This unique characteristic has spurred research into their potential as therapeutic alternatives [4,8,9].…”

“…AMPs are synthesized by leukocytes and epithelial cells in different organs [10]. Cathelicidins, a prominent family of AMPs, have been identified in various animal species, including mammals, birds, fishes, and reptiles [7,[11][12][13]. These peptides are initially produced as pro-peptides and are characterized by the presence of a cathelin domain and a protease cleavage site, which is essential for the release of the mature peptide responsible for the anti-microbial activity [14,15].…”

Characterization of a Novel Antimicrobial Peptide Bacipeptin against Foodborne Pathogens

“…Among them, antimicrobial peptides are of interest because of low ability to induce drug resistance. 13,14 In general, most of marine antimicrobial peptides are isolated from animals, 15,16 and marine microorganisms are also a hot spot for screening novel antimicrobial peptides. 17,18 In our present study, a Bacillus licheniformis (B. licheniformis) M1 was isolated from the sediment of a deep-sea cold spring, which exhibited obvious antimicrobial activities against foodborne pathogens.…”

Avellanin A Has an Antiproliferative Effect on TP-Induced RWPE-1 Cells via the PI3K-Akt Signalling Pathway

“…Naturally occurring cyclic peptides have garnered much attention as a drug discovery resource [ 11 , 12 ]. This is because cyclic peptides are composed of amino acid residues, including nonproteinogenic residues, which are arranged in a three-dimensional structure and have high affinity for their target biomolecules [ 12 ].…”