Orbital Fibroblasts from Patients with Thyroid-Associated Ophthalmopathy Overexpress CD40: CD154 Hyperinduces IL-6, IL-8, and MCP-1

Abstract

Purpose Fibroblast diversity represents an emerging concept critical to our understanding of tissue inflammation, repair and remodeling. Orbital fibroblasts heterogeneously display Thy-1 and exhibit unique phenotypic attributes that may explain the susceptibility of the human orbit to thyroid-associated ophthalmopathy (TAO). In the current study we investigate the role of CD40 ligation upon macrophage chemoattractant protein -1 (MCP-1), IL-6 and IL-8 expression in fibroblasts from patients with TAO. Methods Human orbital fibroblasts were cultured from tissues obtained with informed consent from patients with TAO and from patients undergoing surgery for other, non-inflammatory conditions. The fibroblasts were then examined by flow cytometry, microscopy, and cytokine assays. Results We report that orbital fibroblasts from patients with TAO express elevated levels of CD40. Surface CD40 can be further up-regulated by interferon.γ (IFN-γ) in both TAO and control fibroblasts. This up-regulation is mediated through Jak2 and can be blocked by dexamethasone and AG490, a powerful and specific inhibitor of the tyrosine kinase. Treatment with CD154, the ligand for CD40, up-regulates the expression of IL-6, IL-8 and MCP-1 in TAO fibroblasts, but fails to do so in control cultures. Thy-1+ fibroblasts displayed higher CD40 levels than do their Thy-1− counterparts and are largely responsible for this cytokine production. IL-1β also induces MCP-1, IL-6 and IL-8 more vigorously in TAO-derived fibroblasts. Conclusion Characterization of orbital fibroblasts and their differential expression of cytokines and receptors should prove invaluable in understanding the site-specific nature of TAO and the development of specific therapies.

Mast Cell-derived Prostaglandin D2 Controls Hyaluronan Synthesis in Human Orbital Fibroblasts via DP1 Activation

“…There are few effective pharmacological treatments for TED due, in part, to a poor understanding the pathogenic mechanisms leading to clinical manifestations of TED. Current evidence, including data from our laboratories (3,47,48), suggests that activation of orbital fibroblasts by infiltrating inflammatory cells, particularly T cells and mast cells, plays an important role in TED pathogenesis (49). Orbital fibroblast proliferation and ECM production, particularly HA (50,51), are key events that contribute to manifestations of TED, such as periorbital edema, exophthalmos, and extraocular motility dysfunction (1,52).…”

Thyrotropin and CD40L Stimulate Interleukin-12 Expression in Fibrocytes: Implications for Pathogenesis of Thyroid-Associated Ophthalmopathy

“…The frequency of circulating TSHR+ fibrocytes is increased in patients with GD, and TSH induces the production of IL-6, IL-8, monocyte chemoattractant protein 1 (MCP-1), and TNF-a (11). Orbital fibroblasts from patients with GD express high levels of CD40, and in response to CD40L, these cells produce hyaluronan and cytokines, such as IL-6, IL-8, and prostaglandin E2 (PGE2) (54). Moreover, an increased frequency of CD40+ fibrocytes has been observed in the blood and orbital tissues of patients with GD compared with controls, and the CD40-CD40L signaling pathway in these cells can induce production of IL-6, IL-8, MCP-1, and TNF-a (20).…”

β (CCL2) and α (CXCL10) chemokine modulations by cytokines and peroxisome proliferator-activated receptor-α agonists in Graves' ophthalmopathy

“…Hwang et al (2009) CCL2. Furthermore, Chen et al (2008) found that the expression of CCL2 was higher in GO orbital fat than in the orbital fat of controls and suggested that macrophage infiltration may play an important role in the pathogenesis of GO via overexpression of CCL2.…”

“…Hwang et al (2009) showed that orbital fibroblasts from patients with GO overexpress CD40 and that CD154 (the ligand for CD40) upregulated the expression of CCL2. Furthermore, Chen et al (2008) found that the expression of CCL2 was higher in the orbital fat of GO patients than in controls.…”