MIGRATION OF RETINAL PIGMENT EPITHELIUM CELLS IS REGULATED BY SPHINGOSINE-1- PHOSPHATE

SIMON, MARIA VICTORIA; VERA, MARCELA; PRADO SPALM, FACUNDO; ROTSTEIN, NORA

Congreso; LXII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2017

Retina proliferative diseases, such as diabetic retinopathy,are common causes of blindness. They are characterized byincreased migration of two cell types that normally support retinalfunction: 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). Nowwe analyzed if S1P also regulates RPE cell migration.Cultures of ARPE19 cells, a human retinal pigment epithelial cellline, were supplemented with 5 μM S1P and migration was evaluatedby scratch-wound assays. To investigate whether ARPE19 cellssynthesized S1P to promote migration, cultures were treated with 30μM sphingosine kinase 1 inhibitor 2 (SphKI2), a SphK1inhibitor. Toanalyze the role of PI3K and ERK/MAPK signaling pathways in cellmigration, cultures were pre-incubated with10 μM LY294002 and 10μM U0126 -a PI3K and ERK/MAPK inhibitor, respectively- beforeS1P supplementation.S1P addition significantly enhanced RPE cell migration; after24hours, migration in S1P- supplemented cells doubled comparedto control conditions. Pre-treatment with SphKI2 reduced by 30%the migration observed in controls, implying endogenous synthesisof S1P promoted RPE cell migration. Addition of exogenous S1P toSphKI2- treated cultures partially restored cell migration, suggestingS1P acts as an intra and extracellular cue. Finally, S1P activatedboth PI3K and ERK/MAPK signaling pathways to induce ARPE migration. Cultures pre-treated with LY294002 or U0126 and then withS1P barely showed 3% and 0.1%, respectively, of the migration observedin S1P-supplemented cultures.Our results suggest that RPE cells synthesize S1P, which activatesPI3K and ERK/MAPK pathways to induce migration and theincrease in S1P levels exacerbates this migration. Since deregulationof thisprocess is involved in several retinal pathologies, modulationof S1P signaling emerges as a potential tool for treating thesediseases.