Anti-Yersinia Activity of Cryptdin-2: A Paneth Cell Peptide

Abstract

In view of the emerging antibiotic(s) resistance in pathogens, there is a renewed interest in clinical medicine to exploit novel agents with a wide range of actions over several pathogens. Therefore, in the present study, bactericidal efficacy of cryptdin-2 against Yersinia enterocolitica was evaluated. Cryptdin-2 exhibited strong bactericidal activity against Y. enterocolitica at the minimum bactericidal concentration (MBC) of 21 μg/ml. Scanning electron microscopic investigations of cryptdin-2 treated bacterial cells revealed that the peptide was able to induce significant morphological alterations in terms of destructive pore formation and damaged membrane confirming its membrane dependent bactericidal activity. N-phenyl napthylamine (NPN) uptake assay in the presence of sublethal, lethal as well as twice the lethal concentrations further confirmed the membrane-dependent mode of action of cryptdin-2 which indicated that the peptide could permeabilize the membrane of Y. enterocolitica. Additionally, the peptide interfered with DNA, RNA as well as protein synthesis in Y. enterocolitica, with maximum inhibition observed for protein synthesis. Thus, the biochemical and biophysical alterations observed in the treated cells in terms of macromolecular synthesis and membrane permeabilization respectively, correlated well with the bactericidal activity. In view of the antibacterial efficacy of the peptide against Salmonella typhimurium and Entamoeba histolytica, observed in our earlier studies, along with its inhibitory potential against Y. enterocolitica as demonstrated in the present study, suggests that it may be exploited as a broad-spectrum antimicrobial agent against enteric infections.