Multiple Hepcidins in a Teleost Fish, Dicentrarchus labrax: Different Hepcidins for Different Roles.
Teleost fish rely heavily on their innate immunity for an adequate response against pathogens and environmental challenges, with the production of antimicrobial peptides being one of their first lines of defense. Among those is hepcidin, a small cysteine-rich antimicrobial peptide that is also the key regulator of iron metabolism. Although most mammals possess a single hepcidin gene, with a dual role in both iron metabolism regulation and antimicrobial response, many teleost fish present multiple copies of hepcidin, most likely because of genome duplications and positive Darwinian selection, suggesting that different hepcidins may perform different functions. To study the roles of hepcidin in teleost fish, we have isolated and characterized several genes in the European sea bass (Dicentrarchus labrax) and evaluated variations in their expression levels in response to different experimental conditions. Although several hepcidin genes were found, after phylogenetic analysis they could be clustered in two groups: hamp1-like, with a single isoform similar to mammalian hepcidins, and hamp2-like, with several isoforms. Under experimental conditions, hamp1 was upregulated in response to iron overload and infection and downregulated during anemia and hypoxic conditions. Hamp2 did not respond to either iron overload or anemia but was highly upregulated during infection and hypoxia. In addition, Hamp2 synthetic peptides exhibited a clear antimicrobial activity against several bacterial strains in vitro. In conclusion, teleost fish that present two hepcidin types show a degree of subfunctionalization of its functions, with hamp1 more involved in the regulation of iron metabolism and hamp2 mostly performing an antimicrobial role.
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Ferro e Imunidade Inata, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal; and jneves@ibmc.up.pt.
João V
JV
Neves
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Ferro e Imunidade Inata, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal; and.
Carolina
C
Caldas
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Ferro e Imunidade Inata, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal; and.
Inês
I
Vieira
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Ferro e Imunidade Inata, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal; and.
Miguel F
MF
Ramos
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Ferro e Imunidade Inata, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal; and Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.
Pedro N S
PN
Rodrigues
D000595:Amino Acid Sequence; D000740:Anemia / Q000378:metabolism; D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism; D001483:Base Sequence; D001492:Bass / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D005393:Fish Diseases / Q000276:immunology; D005786:Gene Expression Regulation; D064451:Hepcidins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism; D007113:Immunity, Innate; D007501:Iron / Q000378:metabolism; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics*; D016415:Sequence Alignment
D000890:Anti-Infective Agents; D064451:Hepcidins; D020033:Protein Isoforms; D007501:Iron