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Updated: Mar 2, 2026
A Pipeline to Investigate the Structures and Signaling Pathways of Sphingosine 1-Phosphate Receptors
Published on: June 8, 2022
Sphingosine-1-Phosphate Mediates Fibrosis in Orbital Fibroblasts in Graves' Orbitopathy
JaeSang Ko1, Min Kyoung Chae1, Joon H Lee2
1Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
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 CSE-induced 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.
Insights
Sphingosine-1-phosphate (S1P) drives fibrosis in Graves' orbitopathy (GO) orbital fibroblasts. Blocking S1P signaling reduced fibrosis and tissue remodeling proteins, suggesting S1P modulation as a potential GO therapy.
Area of Science:
- Ophthalmology
- Endocrinology
- Cell Biology
Background:
- Graves' orbitopathy (GO) is an autoimmune condition affecting orbital tissues.
- Fibrosis in orbital fibroblasts contributes to the pathogenesis of GO.
- The role of sphingosine-1-phosphate (S1P) in GO-related fibrosis is not fully understood.
Purpose of the Study:
- To investigate the effect of S1P on fibrosis in orbital fibroblasts from patients with GO.
- To explore the potential of modulating S1P signaling as a therapeutic strategy for GO.
Main Methods:
- Orbital fibroblasts from GO patients and controls were cultured.
- Cells were treated with TGF-β, cigarette smoke extract (CSE), or IL-1β, with or without S1P receptor (S1PR) antagonists/modulators or a sphingosine kinase-1 blocker.
- Expression of fibrosis and tissue remodeling proteins was assessed using Western blotting.
Main Results:
- TGF-β and CSE increased S1P and S1PR expression in GO fibroblasts.
- S1P receptor blockade and inhibition of S1P synthesis reduced the expression of collagen Iα, fibronectin, and α-SMA induced by TGF-β and CSE.
- Exogenous S1P upregulated fibrosis and tissue remodeling markers in a dose-dependent manner.
Conclusions:
- S1P signaling promotes fibrosis and tissue remodeling in GO orbital fibroblasts.
- Blocking S1P activity or synthesis decreases the expression of key fibrotic and remodeling proteins.
- Modulation of S1P activity holds therapeutic promise for suppressing fibrosis in GO.
