ARPE-19 pigment epithelial cells and docosahexaenoic acid promote spatial organization and differentiation of retina photoreceptors in vitro.

POLITI LE; GERMAN OL; ROTSTEIN N.P.; RODRIGUEZ-BOULAN E.; BUZZI E.

Fort Lauderdale, Florida, EEUU

Congreso; ARVO Annual Meeting,; 2007

Association for Research in Vision and Ophthalmology (ARVO)

ARPE-19 Pigment Epithelial Cells And Docosahexaenoic Acid Promote Spatial Organization and Differentiation Of Retina Photoreceptors In Vitro Politi Luis(1); German, Lorena. (1); Rotstein Nora (1);  Rodríguez-Boulan, Enrique. (2)  Buzzi, Edgardo. (1) (1)INIBIBB, UNS-CONICET. 8000 Bahía Blanca and (2) M. Dyson Vis. Res. Inst. Cornell Univ., NY, USA. inpoliti@criba.edu.ar  Purpose: Retina photoreceptors depend on the continuous supply of several cellular and molecular cues for their development and function. Among others, docosahexaenoic acid (DHA) is required for their survival and differentiation, and interaction with retinal pigment epithelial (RPE) cells is essential for their functionality. However, this interaction depends on the establishment of a very precise spatial arrangement between photoreceptors and RPE cells. We here investigated whether the interactions between these cell types contribute to establish this spatial arrangement and to promote photoreceptor development in culture and whether DHA modulated these interactions. Methods:we cocultured retinal neurons with ARPE-19 cells, with or without DHA. These cocultures offered the advantage of experimentally altering the spatial organization naturally occurring in vivo, by alternatively seeding photoreceptors on ARPE-19 cells or ARPE-19 cells on photoreceptors and analyzing the reorganization of their spatial localization. The effects of ARPE-19 cells on photoreceptor survival, differentiation and axonal outgrowth, in cocultures with or without DHA were also analyzed. Results: When pure retinal neurons were cultured with ARPE-19 cells, strict topological restrictions were observed. When neurons were seeded over RPE cells, photoreceptors attached to the epithelial apical surfaces as occurs in vivo. However, when epithelial cells were seeded over neurons, exposing to them their basal membranes, RPE cells rapidly detached photoreceptors from their substrata and positioned below these neurons. This displacement was blocked by the metalloproteinase inhibitor TIMP-1, suggesting that metalloproteinases might participate in this reorganization. ARPE-19 cells promoted photoreceptor axonal outgrowth and oriented the outgrowing axons away from RPE cells. In addition, they protected photoreceptors from apoptosis and enhanced their differentiation. DHA, which promotes photoreceptor survival and differentiation in pure neuronal cultures, did not further enhance these effects in co-cultures. However, its addition increased the uptake of opsin from photoreceptors by RPE cells. Conclusions: These results suggest that RPE cells might participate in establishing the process of pattern formation of the retina. The mutual interplay between these cells and DHA might also contribute not only to enhance RPE differentiation but also to regulate photoreceptor survival and differentiation.