Identification of Antibacterial Activity of Hepcidin From Antarctic Notothenioid Fish

Abstract

Hepcidin is a small peptide composed of signal peptide, propeptide, and the bioactive mature peptide from N terminal to C terminal. Mature hepcidin is an antibacterial peptide and iron regulator with eight highly conserved cysteines forming four intramolecular disulfide bonds, giving it a β sheet hairpin-like structure. Hepcidin homologs are found in a variety of vertebrates, especially fish, and their diversity may be associated with different habitats and different levels of pathogens. Dissostichus mawsoni, an Antarctic notothenioid fish that lives in the coldest water unlike most places of the world, with at least two hepcidin variants with eight cysteines. We confirmed the formation process of activated mature hepcidins from D. mawsoni in Chinese hamster ovary (CHO) cell line, obtained recombinant hepcidin protein from prokaryotes, and characterized its binding ability and antibacterial activity against varying bacteria. The expression of hepcidin in CHO cell line showed that the prepropeptide of Dmhep_8cysV1 and Dmhep_8cysV2 cleavage into smaller mature peptide. The antibacterial assay and flow cytometry showed that Dmhep_8cysV1, Dmhep_8cysV2, and Drhep bound to different bacteria and killed them with different minimum inhibitory concentration. These data suggest that hepcidin plays an important role in the innate immunity of D. mawsoni and is of great value in improving resistance to pathogens.

Anti-microbial activity and immunomodulation of recombinant hepcidin 2 and NK-lysin from flounder (Paralichthys olivaceus)

“…The results showed that PoHep2 and PoNKL were expressed in all the tissues examined. In Dissostichus mawsoni and Danio rerio, hepcidin mRNA expression was detected in ten different tissues where the hepcidin mRNA in the liver often was highest [33]. In this study, the highest expression of PoHep2 was also found in the liver (Fig.…”

Identification of antibacterial activity of LEAP2 from Antarctic icefish Chionodraco hamatus

“…The search for antimicrobial peptides to target bacterial diseases in Antarctic fish is therefore urgent. Liver‐expressed antimicrobial peptide 1 (Hepcidin) has evolved in Antarctic fish as a subtype containing four cysteines (Xu et al, 2008), relative to LEAP1 containing eight cysteines, which has increased antimicrobial activity (Borkar et al, 2019; Liu et al, 2022). Liver‐expressed antimicrobial peptide 2 is the second antimicrobial peptide, containing four cysteines, whose antimicrobial activity has not been investigated in Antarctic fish.…”