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

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.

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.

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.

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.