TNFα drives disease-specific chemokine networks and orbital tissue remodeling in a preclinical model of thyroid eye disease.

BACKGROUND

Thyroid eye disease (TED) is characterized by orbital inflammation, fibroblast activation, and pathological tissue remodeling. While autoimmunity to the thyrotropin receptor (TSHR) initiates disease, the contribution of proinflammatory cytokines, such as tumor necrosis factor (TNFα), to fibroblast differentiation and extracellular matrix (ECM) remodeling remains incompletely understood.

METHODS

A mouse model of TED was generated by immunization with a plasmid encoding the human TSHR A-subunit. Orbital tissues were analyzed for immune cell infiltration and cytokine expression. Primary murine orbital fibroblasts (mOFs) from TSHR- and control β-Gal-immunized mice were treated with TNFα or IFNγ. The expression of cytokines, chemokines, adiponectin, TGFβ, hyaluronic acid (HA), and hyaluronan synthase 2 (HAS2) was assessed by ELISA, qPCR, and western blotting.

RESULTS

TSHR-immunized mice displayed marked orbital macrophage infiltration accompanied by elevated TNFα levels. TNFα induced a strong proinflammatory response in mOFs, with robust IL-6 and IL-8 secretion and an IL-6-dominant profile in TSHR-derived cells. TNFα also upregulated CCL2, CCL20, and CXCL10, supporting enhanced immune cell recruitment. Moreover, TNFα reduced adiponectin while increasing TGFβ in TSHR mOFs, indicating activation of profibrotic pathways. TNFα significantly increased HA production and HAS2 expression, particularly in TSHR-derived fibroblasts, demonstrating enhanced ECM synthesis under autoimmune conditions.

CONCLUSION

These findings identify TNFα as a central regulator linking inflammation to adipogenic suppression, profibrotic signaling, and ECM remodeling in a TSHR-immunized mouse model of TED. Enhanced HA/HAS2 induction underscores a disease-specific sensitivity of orbital fibroblasts to TNFα. Targeting TNFα or its downstream IL-6/TGFβ-ECM axis may offer a promising therapeutic strategy to limit pathological tissue remodeling in TED.