MIGRATION OF RETINA GLIAL CELLS REQUIRES THE SYNTHESIS OF CERAMIDE-1-PHOSPHATE

VERA, M.; PRADO SPALM, F.; SIMON, MARIA VICTORIA; ROTSTEIN N. P.

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

Retina proliferative diseases are major causes of visual dysfunction.Müller glial cells (MGC),the major glial cell type in the retina,and retinal pigment epithelial (RPE) cells play a key role in thesediseases. Injuries to the retina exacerbate their proliferation and migrationthat contribute to visual loss. The molecular cues involved inthese processes are still ill defined. We demonstrated that a sphingolipid,sphingosine-1-phosphate (S1P), promotes glial migration.We now investigated whether ceramide-1-phosphate (C1P), whichcontrols proliferation and migration in certain cell types,participatesin glial and RPE cell migration.We evaluated migration in primary glial cultures,prepared fromnewborn rat retinas, and in a RPE cell line (ARPE19), by the woundrepair assay. Addition of 10 μM C1P doubled MGC migration. Toinvestigate whether C1P synthesis was required forglial migration,we first established by PCR that MGC expressed ceramide kinase(CerK), the enzyme catalyzing C1P synthesis. NVP231, a CerK inhibitor,completely prevented glial migration, which was not restoredby C1P addition. Noteworthy, ARPE19 cell migration was also inhibitedby NVP231. We then investigated the signaling pathwaysinvolved in C1P effect. Inhibiting the PI3K and the ERK/MAPK pathways,with LY294002 and U0126, respectively, decreased glial migration,both in control and C1P-treated cultures. SP6000, a Jun Kinhibitor, also blocked C1P-induced glial migration. C1P activatesa cytoplasmic phospholipase A2 (cPLA2) in different cell types.Pre-treatment with ATK, a cPLA2 inhibitor, markedly reduced glialmigration in control and C1P-treated cultures.These results show that C1P promotesglial migration through theactivation of cPLA2 and the Jun K, the PI3K and the ERK/MAPKpathways. They also imply that exogenous C1P promotes C1P endogenoussynthesis to stimulate glial and epithelial cell migration,supporting C1P as a central cue for regulating migration in thesecells.