Lif Deficiency Leads to Iron Transportation Dysfunction in Ameloblasts

Area of Science:

• Biochemistry
• Developmental Biology
• Oral Biology

Background:

• Leukemia inhibitory factor (LIF) is a cytokine involved in various physiological processes, including skeletal metabolism and stem cell pluripotency.
• The specific role of LIF in tooth development, particularly in enamel formation, remains largely uncharacterized.

Purpose of the Study:

• To investigate the impact of LIF deficiency on tooth development.
• To elucidate the mechanisms by which LIF influences enamel formation and iron homeostasis during tooth development.

Main Methods:

• Utilized Lif-knockout mice (Lif-/-) and wild-type littermates for comparative analysis.
• Employed scanning electron microscopy, computed tomography, 3D imaging, microhardness, and acid resistance assays to assess incisor structure and properties.
• Quantified iron content using energy-dispersive X-ray spectroscopy and Prussian blue staining.
• Analyzed ameloblast morphology and expression of iron transport proteins (Tfrc, Slc40a1) via histology, qRT-PCR, immunohistochemistry, and Western blot.
• Investigated the role of the Stat3 signaling pathway using a Stat3 inhibitor (Stattic).

Main Results:

• Lif-knockout mice exhibited whiter, shorter incisors with reduced microhardness and acid resistance compared to wild-type mice.
• Incisors from Lif-knockout mice showed significantly lower iron content, despite comparable systemic iron levels.
• Histological analysis revealed shorter maturation-stage ameloblasts in Lif-knockout mice.
• Expression of iron transport proteins Tfrc and Slc40a1 was decreased in Lif-knockout mice and Lif-knockdown ameloblast cells.
• LIF stimulation upregulated Tfrc and Slc40a1, an effect inhibited by Stattic, indicating mediation via the Stat3 pathway.

Conclusions:

• LIF deficiency impairs iron transport in maturation-stage ameloblasts, negatively affecting enamel quality and incisor length.
• LIF plays a crucial role in regulating iron homeostasis during tooth development.
• LIF modulates the expression of iron transport proteins Tfrc and Slc40a1 through the Stat3 signaling pathway, highlighting a novel mechanism in enamel formation.