MULLER GLIAL CELLS IN RETINAL REGENERATION

POLITI L. E..; VOLONTÉ Y. A.; DIBO, M; SIMÓN M.V.; GERMAN O.L.; ROTSTEIN N. P.

San Pablo

Congreso; XXX Reunião Anual da FeSBE; 2015

Federação de Sociedades de Biologia Experimental-FeSBE

Muller Glial cells (MGC) are known to be stem cells in the retina. Their regenerative capacity is lower in mammals than in fish; it is not enough to restore photoreceptor losses occurring in retina degenerations, such as retinitis pigmentosa or its animal model, the rd mouse. Since no evidences of neuronal regeneration are observed in rd retinas, we hypothesize that, in addition to the already known molecular abnormalities of rd photoreceptors, MGC may present alterations that affect their regenerative capacity. We investigated whether MGC in ?rd? retinas presented morphological or molecular abnormalities by culturing mixed cultures of retinal photoreceptor progenitors and MGC from rd and wild type mice. We found that in rd cultures, photoreceptor progenitors took up less BrdU and showed more nuclear fragmentation than in its wild type counterpart. On the other hand, rd MGC expressed less nestin and had more nuclei evidencing an abnormal distribution of nuclear lamina than those in wild type mice. These results suggest a decreased proliferative capacity in rd retinal cells.MGCs affect the normal functioning of photoreceptors. Conversely, photoreceptor abnormalities could alter the neuron-glia ?dialogue?. The alterations of MGC could be adscribed to a defect inherent to them or, alternatively to an unbalance in this ?dialogue? causing MGC malfunction which, in turn, would end up in a regenerative failure. To test this hypothesis, we co-cultured wild type MGC with either wild type or rd photoreceptors, and compared the expression of nestin, and BrdU uptake in both cultures. The results showed that wild type MGC showed less nestin expression and BrdU uptake when co-cultured with rd photoreceptors than when co-cultured with wild type photoreceptors.Altogether, these results suggest that rd photoreceptors affect the normal functioning of MGC, and might contribute to the regenerative failure in the rd retinas.