Ferritin M of Paralichthys olivaceus possesses antimicrobial and antioxidative properties

Area of Science:

• Biochemistry
• Molecular Biology
• Immunology

Background:

• Ferritin is essential for iron homeostasis.
• Ferritin M (FerM) subtypes are involved in iron metabolism and cellular defense.
• Understanding fish ferritin function is vital for aquaculture and comparative biology.

Purpose of the Study:

• To identify and characterize Japanese flounder ferritin M (PoFerM).
• To investigate the biological properties of PoFerM, including its iron-chelating, antimicrobial, and antioxidative activities.
• To determine the role of conserved structural centers in PoFerM function.

Main Methods:

• Identification and sequence analysis of PoFerM.
• Expression analysis in various Japanese flounder tissues and after bacterial challenge.
• Recombinant protein expression and purification (rPoFerM and rPoFerMM mutant).
• In vitro assays for iron-chelating activity, bacterial growth inhibition, and oxidative protection.

Main Results:

• PoFerM is a 176-amino acid protein with conserved ferroxidase and nucleation centers.
• PoFerM is expressed in multiple tissues, with highest levels in blood.
• Bacterial infection upregulates PoFerM expression in immune organs.
• Recombinant PoFerM demonstrated iron-chelating, antimicrobial, and antioxidant properties.
• Mutating conserved centers abolished these functions, highlighting their importance.

Conclusions:

• PoFerM functions as an iron chelator with significant antimicrobial and antioxidative capabilities.
• The conserved ferroxidase and nucleation centers are essential for PoFerM's biological activities.
• PoFerM plays a critical role in the innate immune response and iron homeostasis in Japanese flounder.