Role of Hepcidins from Black Rockfish (Sebastes schlegelii) in Iron-Metabolic Function and Bacterial Defense

Abstract

<jats:p>Hepcidin, an antimicrobial peptide produced by the liver, also controls the iron balance and regeneration in vertebrates. Two types of hepcidin (Hamp1 and Hamp2) have been found in the bodies of black rockfish (Sebastes schlegelii). The full-length cDNA of hepcidin was cloned to enable a study of the antibacterial roles of these two hepcidins (Hamp) in black rockfish. The antimicrobial function of recombinant hepcidins was tested both in vitro and in vivo by the synthesis in Escherichia coli of recombinant hepcidin (approximately 11 kDa) from black rockfish. The recombinant hepcidins inhibited the growth of two bacterial species, Streptococcus iniae FP5228 and Pseudomonas aeruginosa, at various concentrations, in vitro after 6 h post-incubation, respectively. During infection, the production of ferroportin was reduced, suggesting the preservation of iron to prevent microbial proliferation. In vivo administration of Hamp1, but not Hamp2, synthetic peptides induced a substantial reduction in the expression of ferroportin, suggesting that in black rockfish with two forms of hepcidin, ferroportin production is regulated by the iron-regulator Hamp1, and not by the dedicated antimicrobial Hamp2. The findings of this study suggest the various antimicrobial roles of these two types of hepcidin.</jats:p>

Early innate immune responses in European sea bass (Dicentrarchus labrax L.) following Tenacibaculum maritimum infection

“…This hepcidin dynamic was already described for other fish species ( 109 – 112 ). These results are in accordance with other studies that also demonstrated the regulation of hepcidin and ferroportin by inflammatory signals induced by a pathogen ( 108 , 113 – 116 ).…”

Embracing the era of antimicrobial peptides with marine organisms

“…Another well-known function of hepcidins is iron regulation. 31 Recently identified hepcidins include the Lc-HepL from large yellow croaker Larimichthys crocea , Hamps from the blackfish Sebastes schlegelii , Pv-hepcidin from the lionfish Pterois volitans etc. , which are effective in killing human or aquatic pathogenic bacteria like Vibrio harveyi and S. aureus , Pseudomonas aeruginosa as well as some parasites.…”

Participation of Hepcidins in the Inflammatory Response Triggered by λ-Carrageenin in Gilthead Seabream (Sparus aurata)

“…Specifically, it has only been studied in a few fish species such as Danio rerio (Jiang et al 2017 ), Salmo trutta (Huang et al 2019 ), Oncorhynchus mykiss (Álvarez et al 2014 ), Dicentrarchus labrax (Rodrigues et al 2006 ), or Sparus aurata (Cuesta et al 2008 ). Recently, the expression of hepcidins has also been studied during the larval development of zebrafish (Caccia et al 2017 ) and in some adult fish species [ Ictalurus punctatus (Bao et al 2006 ), Oreochromis mossambicus (Huang et al 2007 ) Cyprinus carpio (Yang et al 2014 ) Sebastes schlegelii (Ma et al 2020 ), and Acrossocheilus fasciatus (Zhu et al 2023 )].…”