PURPOSE: Graves' ophthalmopathy (GO) is characterized by the infiltration of immune cells into the orbit, a process in which cytokines play a central role. Orbital fibroblasts are potent producers of cytokines on different stimuli. Recently, the authors showed increased expression of the PDGF-B chain in GO orbital tissue. The dimeric PDGF-BB molecule has been described to activate the NF-kappaB pathway, which is well recognized for its role in regulating cytokine production. This study was conducted to determine the role of PDGF-BB in the production of proinflammatory cytokines by orbital fibroblasts in GO.
METHODS: Orbital, lung, and skin fibroblasts were stimulated with PDGF-BB, and cytokine (IL-1beta, IL-6, IL-8, IL-16, CCL2, CCL5, CCL7, TNF-alpha) production was measured by ELISA. Involvement of NF-kappaB activation through PDGF signaling was investigated by electrophoretic mobility shift assay, specific NF-kappaB inhibitors, and the PDGF-receptor kinase inhibitor imatinib mesylate.
RESULTS: IL-6, IL-8, CCL2, CCL5, and CCL7 production by orbital fibroblasts was increased by PDGF-BB stimulation, whereas IL-16, IL-1beta, and TNF-alpha production was not affected. PDGF-BB induced NF-kappaB activity in orbital fibroblasts, and both NF-kappaB inhibitors and imatinib mesylate reduced PDGF-BB-induced cytokine production. Similar, but less vigorous, effects of PDGF-BB on cytokine production were observed in lung and skin fibroblasts.
CONCLUSIONS: PDGF-BB is a potent inducer of proinflammatory cytokines via the NF-kappaB pathway in orbital fibroblasts, whereas cytokine production by fibroblasts from other anatomic locations showed a moderate response. These data suggest a possible role for PDGF-BB in regulating orbital inflammation in GO and identify the PDGF signaling cascade as a therapeutic target in GO.
|Number of pages||6|
|Journal||Investigative ophthalmology & visual science|
|Publication status||Published - Feb 2010|
- Angiogenesis Inducing Agents/pharmacology
- Cells, Cultured
- Electrophoretic Mobility Shift Assay
- Enzyme-Linked Immunosorbent Assay
- Fibroblasts/drug effects
- Graves Ophthalmopathy/metabolism
- Imatinib Mesylate
- Middle Aged
- NF-kappa B/metabolism
- Orbit/drug effects
- Platelet-Derived Growth Factor/pharmacology
- Protein Kinase Inhibitors/pharmacology
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Proto-Oncogene Proteins c-sis
- Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors