Amphibian antimicrobial peptides and Protozoa: Lessons from parasites

Abstract

Antimicrobial peptides (AMPs) from amphibians and other eukaryotes recognize pathogenicity patterns mostly related to differences in membrane composition between the host and a variety of bacterial, fungal and protozoan pathogens. Compared to the other two groups, protozoa are fairly neglected targets in antimicrobial chemotherapy, despite their role as causative agents for scourges such as malaria, amoebiasis, Chagas' disease or leishmaniasis. Herein we review the scarce but growing body of knowledge addressing the use of amphibian AMPs on parasitic protozoa, the adaptations of the protozoan to AMP pressure and their impact on AMP efficacy and specificity, and the current and foreseeable strategies for developing AMPs into practical therapeutic alternatives against parasitic disease.

Covalent immobilization of antimicrobial peptides (AMPs) onto biomaterial surfaces

“…Gabriel et al [70] concluded that only N-terminal conjugation permitted the appropriate parallel orientation of the peptide helices, which is required for interaction among the peptide molecules and between the peptides and the lipid double layer during membrane pore formation. These results are supported by the reported key role of basic lysine side-chains (and of those from other basic amino acids, as arginine or histidine) in the bioactivity of cationic AMP [39][40][41][42], which could explain the deleterious effect of AMP immobilization through Lys e-amino groups towards antimicrobial activity. The possibility of C-terminal peptide immobilization should be considered as this orientation may achieve similar specific activity as N-terminal conjugation.…”

“…There is a clear need for a broad-spectrum antimicrobial that prevents colonization of biomaterials, minimizes the development of bacterial resistance, displays long-term stability, even through the sterilization process, and has a low cytotoxic profile. Antimicrobial peptides have the potential to meet these criteria [39][40][41][42] and therefore represent a promise for the new generation of antimicrobial surfaces.…”

“…The decline in the effectiveness of current therapies has led to a search for new kinds of agents, including antibiotics based on antimicrobial peptides (AMPs), which are part of the innate immune system of all multicellular organisms [39][40][41][42][43]. So far, more than 750 different AMPs have been isolated from a wide variety of animals, plants, bacteria, fungi and viruses [39][40][41][42]44]. The AMPs comprise a chemically and structurally heterogeneous family.…”

“…Uncontrolled immobilization can be especially detrimental when involving peptide amine groups, as these amine groups are normally provided by lysines which are key amino acids in the majority of cationic amphipathic AMPs [39][40][41][42].…”

Beyond Lysozyme: Antimicrobial Peptides Against Malaria

“…Some other naturally occurring or synthetic peptides have been shown to have antimalarial activity. The antiprotozoal activity of AMPs from amphibian origin was reviewed by Rivas and colleagues (Rivas et al 2009). …”