Diversity, Antimicrobial Action and Structure-Activity Relationship of Buffalo Cathelicidins

Abstract

Cathelicidins are an ancient class of antimicrobial peptides (AMPs) with broad spectrum bactericidal activities. In this study, we investigated the diversity and biological activity of cathelicidins of buffalo, a species known for its disease resistance. A series of new homologs of cathelicidin4 (CATHL4), which were structurally diverse in their antimicrobial domain, was identified in buffalo. AMPs of newly identified buffalo CATHL4s (buCATHL4s) displayed potent antimicrobial activity against selected Gram positive (G+) and Gram negative (G-) bacteria. These peptides were prompt to disrupt the membrane integrity of bacteria and induced specific changes such as blebing, budding, and pore like structure formation on bacterial membrane. The peptides assumed different secondary structure conformations in aqueous and membrane-mimicking environments. Simulation studies suggested that the amphipathic design of buCATHL4 was crucial for water permeation following membrane disruption. A great diversity, broad-spectrum antimicrobial action, and ability to induce an inflammatory response indicated the pleiotropic role of cathelicidins in innate immunity of buffalo. This study suggests short buffalo cathelicidin peptides with potent bactericidal properties and low cytotoxicity have potential translational applications for the development of novel antibiotics and antimicrobial peptidomimetics.

Antimicrobial activity of the indolicidin‐derived novel synthetic peptide In‐58

“…Performed atomic‐force microscopy revealed a large aggregate of cells treated with 100 μg mL ‐1 indolicidin (Figure S2). Similar results were shown for short buffalo cathelicidins and eosinophilic cationic proteins . The treatment of bacteria by these peptides promoted agglutination of the cells through rearrangement of the proteins that expose the hydrophobic patch of the peptide leading to the disruption of the lipophilic barrier of the cells.…”

Screening and characterization of a novel high‐efficiency tumor‐homing cell‐penetrating peptide from the buffalo cathelicidin family

“…The cathelicidin family is an important and widely studied group of mammalian AMPs . buCATHL4s, which were identified in buffalo, are a series of new homologs of the cathelicidin4 (CATHL4) family . The amino acid sequences of buCATHL4s are rich in hydrophobic tryptophans and cationic arginines, which is similar to the composition of amino acids in cell‐penetrating peptides.…”

“…Buffalo CATHL4 (buCATHL4) is a recently discovered family of buffalo‐derived AMPs with broad‐spectrum bactericidal activities against gram‐positive and gram‐negative bacteria but has reduced cytotoxicity to eukaryotic cells at bactericidal concentrations. Buffalo CATHL4 AMPs are rich in arginine and aromatic amino acid residues, and their antibacterial mechanism is mainly dependent on membrane disruption, leading to membrane instability . There is currently no research reporting whether such AMPs have CPP‐like functions.…”

“…There is currently no research reporting whether such AMPs have CPP‐like functions. In this study, several buCATHL4 members were randomly selected as candidates for CPP screening among 12 newly identified buCATHL4s . These AMP sequences were fused to the enhanced green fluorescent protein (EGFP) gene and expressed in Escherichia coli BL21 (DE3) to investigate their cell‐penetrating activity by fluorescence microscopy and flow cytometry analysis.…”

“…Buffalo CATHL4 AMPs are rich in arginine and aromatic amino acid residues, and their antibacterial mechanism is mainly dependent on membrane disruption, leading to membrane instability. 27 There is currently no research reporting whether such AMPs have CPP-like functions. In this study, several buCATHL4 members were randomly selected as candidates for CPP screening among 12 newly identified buCATHL4s.…”