AUTHOR=Liu Mingli , Hu Ruiqin , Li Wenhao , Yang Wenyi , Xu Qianghua , Chen Liangbiao 

TITLE=Identification of Antibacterial Activity of Hepcidin From Antarctic Notothenioid Fish

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.834477

DOI=10.3389/fmicb.2022.834477

ISSN=1664-302X

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