Transferrin receptor 2 mitigates periodontitis-driven alveolar bone loss

Area of Science:

• * Oral Biology and Pathology
• * Immunology and Inflammation
• * Bone Metabolism and Homeostasis

Background:

• * Periodontitis is a major cause of alveolar bone loss, often more severe in patients with iron overload.
• * The precise mechanisms linking iron overload, periodontitis, and bone loss are not fully understood.
• * Transferrin receptor 2 (Tfr2) is a key regulator of iron homeostasis and has been implicated in bone cell function.

Purpose of the Study:

• * To investigate the role of Tfr2 in the pathogenesis of periodontitis and its impact on alveolar bone.
• * To elucidate the cellular and molecular mechanisms by which Tfr2 deficiency affects osteoclastogenesis and inflammation in periodontitis.
• * To determine the influence of Tfr2 on the dental phenotype under basal and disease conditions.

Main Methods:

• * Experimental periodontitis was induced in Tfr2-deficient (Tfr2^-/-) and wild-type (Tfr2^+/+) mice.
• * Microcomputed tomography and histological analyses were used to assess alveolar bone loss and inflammation.
• * Osteoclast differentiation, gene expression, and signaling pathways (p38-MAPK) were analyzed ex vivo.

Main Results:

• * Tfr2^-/- mice exhibited more severe periodontitis with increased immune cell infiltration and inflammation.
• * Tfr2 deficiency led to greater alveolar bone loss, partly independent of iron levels.
• * Tfr2^-/- osteoclasts showed enhanced differentiation, resorptive activity, and increased p38-MAPK signaling.

Conclusions:

• * Tfr2 plays a critical role in modulating the inflammatory response during periodontitis.
• * Tfr2 deficiency exacerbates periodontitis-induced alveolar bone loss by promoting osteoclastogenesis via p38-MAPK signaling.
• * Targeting Tfr2 or p38-MAPK signaling may offer therapeutic strategies for periodontitis and associated bone loss.