Context: Thyroid eye disease (TED) is a challenging condition owing to relentless orbital tissue remodeling, with thyroid-stimulating hormone receptor (TSHR) in orbital fibroblasts (OFs) serving as a promising therapeutic target.

Objectives: This study seeks to discover potential TSHR inhibitors among FDA-approved drugs and evaluate their effects on TED-OFs.

Design/Participants: Adipose tissues were sourced from the patients with or without TED. Isolated OFs were cultivated in proliferation medium or stimulated for adipogenic/fibrotic differentiation in 2D/3D models, treated by 2'-O-GH (0, 5, 20, and 50μM).

Main Outcome Measures: Using structure-based virtual screening (SBVS), potential TSHR antagonists were identified. Cellular proliferation was analyzed by EdU incorporation, flow cytometry and spheroid size. Adipogenesis was determined by Oil Red O staining, Western blot and immunofluorescence. Fibrosis was assessed using woundhealing assays, Western blot and immunofluorescence. Cyclic adenosine monophosphate (cAMP), hyaluronan and cytokine were quantified by ELISA.

Results: Herein, the FDA-approved drug 2'-O-Galloylhyperin (2'-O-GH) dose-dependently decreased cAMP production and the subsequent CREB phosphorylation stimulated by a TSHR stimulating monoclonal autoantibody M22, which was reversed by a consistently activated mutation of TSHR (L629F). As expected, 2'-O-GH attenuated lipid accumulation in TED-OFs, along with down-regulation of key adipogenic markers. And 2'-O-GH ameliorated hyaluronan production during adipogenesis. Notably, 2'-O-GH dampened wound closure and fibrotic differentiation of TED-OF stimualted by TGF-β1. Correspondingly, proliferation of TED-OFs was halted by 2'-O-GH.

Conclusions: 2'-O-GH promises to prevent the tissue remodeling of TED by exerting inhibitory effects on proliferation, differentiation and hyaluronan deposition by inhibiting TSHR activation, implying its potential therapeutic value for TED.