Sphingosine-1-Phosphate Is a Crucial Signal for Migration of Retina Müller Glial Cells

• Published in: Investigative ophthalmology & visual science Vol. 56; no. 10; pp. 5808 - 5815
• Main Authors: Simón, María V, Prado Spalm, Facundo H, Politi, Luis E, Rotstein, Nora P
• Format: Journal Article
• Language: English
• Published: United States 01.09.2015
• Subjects: Animals; Cell Movement - drug effects; Cell Movement - physiology; Cells, Cultured; Enzyme Inhibitors - pharmacology; Lysophospholipids - pharmacology; Lysophospholipids - physiology; Mitogen-Activated Protein Kinases - antagonists & inhibitors; Neuroglia - drug effects; Neuroglia - physiology; Phosphatidylinositol 3-Kinases - antagonists & inhibitors; Rats; Rats, Wistar; Receptors, Lysosphingolipid; Retina - cytology; Retina - physiology; Signal Transduction - physiology; Sphingosine - analogs & derivatives; Sphingosine - pharmacology; Sphingosine - physiology
• ISSN: 1552-5783; 1552-5783
• DOI: 10.1167/iovs.14-16195

Migration of Müller glial cells is enhanced in proliferative retinopathies, but the mechanisms involved are ill defined. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid synthesized by sphingosine kinase (SphK), which promotes proliferation, migration, and inflammation, acting as an intracellular mediator and activating a family of membrane receptors (S1PRs). We investigated whether S1P regulated glial migration. Müller glial cell cultures from rat retinas were supplemented with 5 μM S1P, and migration was evaluated by scratch-wound assays. Cultures were treated with SphK inhibitor 2 (SphKI 2), a SphK1 inhibitor, or with W146 and BML-241, S1P1 and S1P3 antagonists, respectively, to investigate whether Müller glial cells synthesized S1P and S1P-activated S1PRs to stimulate migration. The effects of LY294002, U0126, and SB203580, which are phosphatidylinositol-3 kinase (PI3K), extracellular signal regulated kinase/mitogen-activated protein kinase (ERK/MAPK), and p38 MAPK inhibitors, respectively, on glial migration were determined. Sphingosine-1-phosphate addition prompted the formation of lamellipodia and enhanced glial migration. SphKI 2 almost completely prevented glial migration in controls; BML-241 inhibited this migration both in controls and in S1P-supplemented cultures, whereas W146 had no significant effect. Pretreatment with LY294002 and U0126 abrogated glial migration; SB203580 decreased it partially, although not significantly. Our results suggest that Müller glial cells synthesize S1P, which signals through S1P3 and the PI3K and ERK/MAPK pathways to induce glial migration. As a whole, our data point to a central role for S1P in controlling glial cell motility. Because deregulation of this process is involved in several retinal pathologies, S1P signaling emerges as a potential tool for treating these diseases.