Physiological and non-physiological forms of iron affect differently proliferation and ferritin synthesis in human...

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Human mononuclear leukocytes (MNL) play a crucial role in immune responses.
• Iron is essential for cellular functions, but its bioavailability and form can influence biological activity.
• The role of specific iron forms in modulating immune cell proliferation and iron metabolism requires further elucidation.

Purpose of the Study:

• To investigate the in vitro effects of different iron formulations on the mitogenic response of human MNL.
• To determine how various iron forms influence ferritin content within MNL.
• To explore the relationship between iron's chemical properties and its biological effects on MNL.

Main Methods:

• In vitro culture of human mononuclear leukocytes (MNL).
• Assessment of MNL proliferative response to mitogen stimulation under varying iron conditions.
• Quantification of ferritin content in MNL exposed to different iron compounds.
• Evaluation of iron-loaded transferrin (FeTF) and apotransferrin (apoTF) effects.

Main Results:

• Iron-loaded transferrin (FeTF) significantly enhanced MNL mitogenic response in serum-free cultures.
• Removal of transferrin (TF) from serum reduced its effectiveness, which was reversible with iron and apoTF.
• Four iron forms stimulated MNL ferritin synthesis, with efficacy increasing as susceptibility to polymerization decreased: FeTF < iron nitrilotriacetate < iron citrate (1:20) < iron citrate (1:1).

Conclusions:

• Iron, particularly in the physiological form of FeTF, may enhance the mitogenic response of human MNL.
• Iron stimulates ferritin synthesis in MNL, likely as a protective cellular mechanism against potentially toxic polymerized iron forms.
• The findings highlight the importance of iron's chemical form in modulating immune cell function and iron homeostasis.