PURPOSE. To investigate the effect of sphingosine-1-phosphate (S1P) on fibrosis in orbital fibroblasts in Graves’ orbitopathy (GO). METHODS. Orbital fibroblasts were cultured from orbital adipose/connective tissues of patients with GO and healthy control subjects. Effects of treatment with TGF-β and cigarette smoke extract (CSE) on S1P receptor (S1PR) messenger RNA (mRNA) and S1P expression were evaluated by real-time polymerase chain reaction and Western blotting. To evaluate the role of S1P in fibrosis, cells were pretreated with W146 (S1PR1 antagonist); JTE013 (S1PR2 antagonist); FTY720 (S1PR1 modulator); or 5C (sphingosine kinase-1 blocker) for 1 hour before stimulation with TGF-β, CSE, or IL-1β. Expression of fibrosis-related proteins (collagen Iα, fibronectin, and α-smooth muscle actin [SMA]) and tissue remodeling-related proteins (matrix metalloproteinases [MMPs] and tissue inhibitor of metalloproteinase [TIMP]-1) was then evaluated by Western blotting. RESULTS. Expression levels of S1PR mRNA and S1P in GO orbital fibroblasts increased upon TGF-β and CSE treatment. Treatment with S1PR blockers and 5C inhibited TGF-β and CSEinduced expression of collagen Iα, fibronectin, and α-SMA, as well as IL-1β-induced expression of MMP-1, MMP-2, MMP-9, and TIMP-1. Exogenous S1P treatment without profibrotic stimulants upregulated collagen Iα, fibronectin, α-SMA, MMP-1, MMP-2, MMP-9, and TIMP-1 expression in a dose-dependent manner. CONCLUSIONS. Blocking of S1PR activity and inhibition of S1P synthesis led to decreased expression of fibrosis and tissue remodeling-related proteins in primary cultures of orbital fibroblasts derived from patients with GO. Thus, modulation of S1P activity might have therapeutic potential in the suppression of fibrosis in GO.
Bibliographical noteFunding Information:
Supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number HI14C1324), and by the Bio & Medical Technology Development Program of the NRF funded by the Korean government, MSIP(2015M3A9E2067031). Disclosure: J. Ko, None; M.K. Chae, None; J.H. Lee, None; E.J. Lee, None; J.S. Yoon, None
All Science Journal Classification (ASJC) codes
- Sensory Systems
- Cellular and Molecular Neuroscience