Porcine Hepcidin Exerts an Iron-Independent Bacteriostatic Activity Against Pathogenic Bacteria

Abstract

Hepcidin was first identified as an antimicrobial peptide and later demonstrated that hepcidin is the long sought hormone to regulate iron homeostasis in mammals. Though its iron regulatory function has been extensively investigated, the studies on its antimicrobial properties are limited. The aim of current study was to evaluate the antibacterial activity of synthetic porcine hepcidin (pHepc) in vitro against pathogen bacteria via radial diffusion, colony forming count, transmission electron microscopy and DNA binding assays. Our results showed that pHepc exerted little bactericidal activity, but possessed bacteriostatic activity by reducing the viable Escherichia coli K88, E. coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Salmonella typhimurium CMCC 50013. pHepc-treated E. coli K88 exhibited longer cells and cytoplasm unevenly distribution, while pHepc-treated S. aureus led to cytoplasm leakage and partly lysis of bacterial cells. Gel retardation assay showed the existence of the binding affinity of pHepc for DNA. In addition, pHepc retained the bacteriostatic activity in a wide range of pH value from 4.0 to 8.0 or in the presence of iron, respectively. Considering the high expression in response to infection and the bacteriostatic activity, pHepc may be an important defense molecule for pig health.

Characterization of Four Liver-Expressed Antimicrobial Peptides from Antarctic Fish and Their Antibacterial Activity

“…Hepcidin is one of the most widespread antimicrobial amphipathic peptides involved in fish innate immunity [20]. It was first identified and isolated in human urine, and denominated as LEAP-1 or hepcidin [1], followed by its detection in other mammal and fish species [10,21,29,[36][37][38][39]. Previous studies had mostly focused on the antimicrobial activities of the hepcidin with eight cysteine residues [2,5,8,[40][41][42], whereas little information is available on the antimicrobial activity of novel, four-cysteine LEAPs isolated from Antarctic fish.…”

“…Thus, ATCUN motif is essential for antimicrobial activity via DNA damage [7]. LEAPs have been identified in many other vertebrates such as fish, chickens, pigs, and mice [8][9][10][11]. LEAPs play a significant role in the fish innate immune system [8,12].…”

Hamp Type-1 Promotes Antimicrobial Defense via Direct Microbial Killing and Regulating Iron Metabolism in Grass Carp (Ctenopharyngodon idella)

“…Hepcidin was originally identified in human blood as an antimicrobial peptide that was mainly expressed by the liver and released into serum [ 1 , 3 ]. In mammals, hepcidin exhibits strong bactericidal activity against various Gram-negative and Gram-positive bacteria [ 4 , 5 ]. As the research advanced, hepcidin was found to be a multifunctional molecule that plays an important role in maintaining iron homeostasis as well [ 6 ].…”