Potential Therapeutic Activity of Berberine in Thyroid-Associated Ophthalmopathy: Inhibitory Effects on Tissue Remodeling in Orbital Fibroblasts.

Purpose: Berberine (BBR), an alkaloid produced by a traditional Chinese plant, was recently attributed multiple effects on lipometabolism, inflammation, and fibrosis. Thyroid-associated ophthalmopathy (TAO) is highly associated with these pathologic changes. Thus, we aimed to examine the potential therapeutic effect of BBR in an in vitro model of TAO. Methods: Orbital fibroblasts (OFs) obtained from control donors (n = 6) or patients with TAO (n = 6) were cultured. The CCK-8 assay was conducted for assessing the optimal concentration range. Oil Red O staining, Western blotting, and quantitative RT-PCR (qRT-PCR) were conducted to assess adipogenesis in OFs. RNA sequencing (RNA-seq) was used to screen the key pathways of the antiadipogenic effect mediated by BBR. Along with incremental concentrations of BBR, IL-1β-induced expression of proinflammatory molecules was determined by ELISA and qRT-PCR. In addition, TGF-β-induced hyaluronan (HA) production and fibrosis were evaluated by ELISA, qRT-PCR, and Western blotting. Results: TAO-OFs, but not control fibroblasts (CON-OFs), were readily differentiated into adipocytes with the commercial medium. Intracellular lipid accumulation was dose-dependently decreased by BBR, and adipogenic markers were also downregulated. Moreover, the PPARγ and AMPK pathways were screened out by RNA-seq and their downstream effectors were suppressed by BBR. Besides, BBR attenuated IL-1β-induced expression of proinflammatory molecules in both TAO-OFs and CON-OFs by blocking nuclear factor-κB signaling. BBR's inhibitory effect on TGF-β-mediated tissue remodeling was also confirmed in OFs. Conclusions: These findings demonstrate BBR has outstanding capabilities of controlling adipogenesis, inflammation, HA production, and fibrosis in OFs, highlighting its potential therapeutic role in TAO management.