Migration of retinal pigment epithelium cells is regulated by sphingosine-1- phosphate.

SIMON M.V.; VERA M; PRADO SPALM F.H.; ROTSTEIN N.P.

Buenos Aires

Congreso; II Reunión Conjunta de Sociedades de Biociencias; 2017

SAIC-SAIB-SAA-SAFE-SAB-SAFIS-SAH-SAI-SAP

Abstract: Retina proliferative diseases, such as diabetic retinopathy, are common causes of blindness. They are characterized by increased migration of two cell types that normally support retinal function: retinal pigment epithelium (RPE) and Müller glial cells (MGC). We previously found that sphingosine-1-phosphate (S1P), a bioactive lipid, increases MGC migration (Simon et al; 2015). Now we analyzed if S1P also regulates RPE cell migration. Cultures of ARPE19 cells, a human retinal pigment epithelial cell line, were supplemented with 5 µM S1P and migration was evaluated by scratch-wound assays. To investigate whether ARPE19 cells synthesized S1P to promote migration, cultures were treated with 30 µM sphingosine kinase 1 inhibitor 2 (SphKI2), a SphK1inhibitor. To analyze the role of PI3K and ERK/MAPK signaling pathways in cell migration, cultures were pre-incubated with10 µM LY294002 and 10 µM U0126 -a PI3K and ERK/MAPK inhibitor, respectively- before S1P supplementation.S1P addition significantly enhanced RPE cell migration; after 24hours, migration in S1P- supplemented cells doubled compared to control conditions. Pre-treatment with SphKI2 reduced by 30% the migration observed in controls, implying endogenous synthesis of S1P promoted RPE cell migration. Addition of exogenous S1P to SphKI2- treated cultures partially restored cell migration, suggesting S1P acts as an intra and extracellular cue. Finally, S1P activated both PI3K and ERK/MAPK signaling pathways to induce ARPE migration. Cultures pre-treated with LY294002 or U0126 and then with S1P barely showed 3% and 0.1%, respectively, of the migration observed in S1P-supplemented cultures.Our results suggest that RPE cells synthesize S1P, which activates PI3K and ERK/MAPK pathways to induce migration and the increase in S1P levels exacerbates this migration. Since deregulation of thisprocess is involved in several retinal pathologies, modulation of S1P signaling emerges as a potential tool for treating these diseases.