Purinergic signals regulate daily S-phase cell activity in the ciliary marginal zone of the zebrafish retina.
J Biol Rhythms
; 26(2): 107-17, 2011 Apr.
Article
em En
| MEDLINE
| ID: mdl-21454291
Regeneration and growth that occur in the adult teleost retina have been helpful in identifying molecular and cellular mechanisms underlying cell proliferation and differentiation. Here, it is reported that S-phase cell number, in the ciliary marginal zone (CMZ) of the adult zebrafish retina, exhibits day-night variations with a mid-light phase peak. Oscillations persist for 24 h in constant darkness (DD), suggesting control by a circadian component. However, variations in the S-phase nuclei number were rapidly dampened and not present during and after a second day in DD. An ADPßS treatment significantly enhanced S-phase activity at night to mid-light levels, as assessed by in vivo BrdU incorporation in a 2-h interval. Moreover, daylight increase in S-phase cell number was completely abolished when extracellular nucleotide levels or their extracellular hydrolysis by ectonucleoside triphosphate diphosphohydrolases (NTPDases) were significantly disrupted or when a selective antagonist of purinergic P2Y1 receptors was intraocularly injected before BrdU exposure. Extracellular nucleotides and NTPDase action were also important for maintaining nocturnal low levels of S-phase activity in the CMZ. Finally, we showed that mRNAs of NTPDases 1, 2 (3 isoforms), and 3 as well as of P2Y1 receptor are present in the neural retina of zebrafish. NTPDase mRNA expression exhibited a 2-fold increment in light versus dark conditions as assessed by quantitative RT-PCR, whereas P2Y1 receptor mRNA levels did not show significant day-night variations. This study demonstrates a key role for nucleotides, principally ADP as a paracrine signal, as well as for NTPDases, the plasma membrane-bound enzymes that control extracellular nucleotide concentration, for inducing S-phase cell entry in the CMZ-normally associated with retinal growth-throughout the light-dark cycle.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Retina
/
Fase S
/
Receptores Purinérgicos P2Y1
Limite:
Animals
Idioma:
En
Revista:
J Biol Rhythms
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Estados Unidos