Müller glial cells preserve stem cell features in retinal progenitors and induce their differentiation as mature photoreceptors

SIMON, MV; DE GENARO, P; DE LOS SANTOS, B; ROTSTEIN, NP; POLITI, L

HUERTA GRANDE

Congreso; Segunda Reunion Conjunta de Neurociencias; 2010

SOCIEDAD ARGENTINA DE NEUROCIENCIAS Y TALLER DE NEUROCIENCIAS SAN-TAN

Müller  glial  cells preserve cells with multipotent features both in primary and secondary cultures MV., Simon;  C., Abrahan , Pablo de Genaro; B. de los Santos, N. Rotstein,  and L . Politi. Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), CONICET – Universidad Nacional del Sur, Bahía Blanca. Apoptosis of photoreceptors (PR) is the main cause of blindness in retinal neurodegenerations. Since the finding of stem cells in the retina, a promising strategy to avoid vision impairment is to regenerate lost PR.  Using Muller glial cells (MGC), which display stem cell properties, requires establishing how MGC might generate neuroblasts (NB), how to induce these NB to further differentiate into mature neurons and how to avoid apoptosis of the regenerated neurons. To investigate these issues we used pure neuronal and glial primary and secondary cultures, and neuro-glia cocultures. NB, characterized as round, undifferentiated cells that took up Bromodeoxyuridine and expressed nestin and Pax6, were only preserved in long-term primary and secondary neuro-glia cocultures, since they were absent or rapidly disappeared in pure neuronal or pure glial cultures. NB comprised about 63% of the total small, round cells in primary neuro-glia cocultures but dropped to 1% in secondary cocultures; concomitantly, nearly 70% and 10% of round cells in secondary cocultures expressed the PR markers Crx and opsin, respectively; these cells also showed high affinity glutamate uptake, a feature of functional PR. Apoptosis of PR-like cells increased during culture time but addition of sphingosine-1-phosphate (S1P), recently shown to prevent PR apoptosis, decreased their death. Our results suggest that neuron-MGC interactions might be relevant in the preservation or generation of NB and in their further differentiation as PR, while S1P might provide a useful tool to prevent apoptosis in newly generated PR. Supported  by  Agencia Nacional de Promoción Científica;  CONICET y Universidad Nacional del Sur