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Metformin inhibits PDGFβ signaling to suppress hyaluronan and cytokine production in thyroid eye disease
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DOI:10.1016/j.exer.2026.110982.png)
Abstract
En 中文
Thyroid eye disease (TED) is characterized by fibroblast-driven inflammation and extracellular matrix expansion, which contribute to orbital congestion and proptosis. Platelet-derived growth factor-beta (PDGF beta) promotes hyaluronan (HA) synthesis and cytokine production in orbital fibroblasts (OFs); however, whether metabolic modulation can counteract this pathway is unknown. We tested whether metformin, an indirect activator of AMP-activated protein kinase (AMPK), attenuates PDGF beta signaling in TED OFs. Primary OFs from 14 TED and 4 non-TED donors were treated with PDGF beta with or without metformin or the direct AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). PDGF beta elicited markedly greater HA and cytokine responses in TED OFs than in non-TED OFs and suppressed AMPK phosphorylation. Metformin treatment restored AMPK phosphorylation, reduced HA accumulation (similar to 2.3-3.1-fold), and decreased IL-6 and IL-8 production. AICAR produced similar AMPK-dependent effects. Mechanistically, metformin attenuated PDGF beta-driven activation of the phosphoinositide 3-kinase (PI3K)-AKT-forkhead box O1 (FoxO1)-nuclear factor kappa B (NF-kappa B) axis, a pro-inflammatory and pro-survival cascade. These data identify PDGF beta-mediated AMPK suppression as a pathogenic mechanism in TED fibroblasts and demonstrate that AMPK reactivation reduces pro-fibrotic and inflammatory signals. Together, these findings support the therapeutic repurposing of metformin in TED.
Keywords:
Thyroid eye disease
Orbital fibroblasts
Metformin
AMP-activated protein kinase
Platelet-derived growth factor
Hyaluronan
Interleukin-6
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