In Vitro Investigation of HIF-1α as a Therapeutic Target for Thyroid-Associated Ophthalmopathy
- Author:
Jeongmin LEE
1
;
Jinsoo LEE
;
Hansang BAEK
;
Dong-Jun LIM
;
Seong-Beom LEE
;
Jung-Min LEE
;
Sang-Ah JANG
;
Moo Il KANG
;
Suk-Woo YANG
;
Min-Hee KIM
Author Information
- Publication Type:Original Article
- From:Endocrinology and Metabolism 2024;39(5):767-776
- CountryRepublic of Korea
- Language:English
-
Abstract:
Background:Thyroid-associated ophthalmopathy (TAO) involves tissue expansion and inflammation, potentially causing a hypoxic microenvironment. Hypoxia-inducible factor (HIF)-1α is crucial in fibrosis and adipogenesis, which are observed in TAO progression. We investigated the effects of hypoxia on orbital fibroblasts (OFs) in TAO, focusing on the role of HIF-1α in TAO progression.
Methods:OFs were isolated from TAO and non-TAO patients (as controls). In addition to HIF-1α, adipogenic differentiation markers including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein (CEBP) were measured by Western blot, and phenotype changes were evaluated by Oil Red O staining under both normoxia and hypoxia. To elucidate the effect of HIF-1α inhibition, protein expression changes after HIF-1α inhibitor treatment were evaluated under normoxia and hypoxia.
Results:TAO OFs exhibited significantly higher HIF-1α expression than non-TAO OFs, and the difference was more distinct under hypoxia than under normoxia. Oil Red O staining showed that adipogenic differentiation of TAO OFs was prominent under hypoxia. Hypoxic conditions increased the expression of adipogenic markers, namely PPARγ and CEBP, as well as HIF-1α in TAO OFs. Interleukin 6 levels also increased in response to hypoxia. The effect of hypoxia on adipogenesis was reduced at the protein level after HIF-1α inhibitor treatment, and this inhibitory effect was sustained even with IGF-1 stimulation in addition to hypoxia.
Conclusion:Hypoxia induces tissue remodeling in TAO by stimulating adipogenesis through HIF-1α activation. These data could provide insights into new treatment strategies and the mechanisms of adipose tissue remodeling in TAO.
