Extracellular nucleotides regulate proliferation of progenitor cells in the adult zebrafish retina during the light:dark cycle.

MJ RICATTI; MP FAILLACE

San Diego

Congreso; 40th Annual Meeting of the Society for Neuroscience; 2010

Society for Neuroscience

•Growth and regeneration that occur in the adult teleost retina by neurogenesis have been helpful in identifying molecular and cellular mechanisms underlying cell proliferation and differentiation. We have found that cell proliferative activity in a neurogenic area known as the ciliary marginal zone (CMZ) of the adult zebrafish retina follows diurnal variations with highest values observed at daylight. ADPβS-treatment significantly enhanced cell division at night to normally observed daylight levels. Diurnal increase of proliferation was completely abolished when extracellular nucleotide levels or their extracellular hydrolysis (by ectonucleotidases called NTPDases) were significantly disrupted. Likewise, proliferative activity was inhibited by using an antagonist of purinergic P2Y1 receptors. Finally, we showed that mRNA levels of NTPDases 1, 2 and 3 as well as of P2Y1 receptors are present in the zebrafish retina. NTPDases mRNA expression exhibited a two-fold increment in light versus dark conditions whereas P2Y1 receptor mRNA levels did not show significant daily variations. Our results demonstrate a key role for nucleotides as well as for NTPDases for the regulation of proliferative activity in the CMZ, associated with retinal growth, throughout the light:dark cycle.