INVESTIGADORES
FAILLACE Maria paula
artículos
Título:
Mitotic Activation of Proliferative Cells in the Inner Nuclear Layer of the Mature Fish Retina: Regulatory Signals and Molecular Markers
Autor/es:
MARÍA PAULA FAILLACE, DAVID JULIAN, JUAN KORENBROT
Revista:
JOURNAL OF COMPARATIVE NEUROLOGY
Editorial:
WILEY-LISS, INC.
Referencias:
Año: 2002 p. 127 - 141
ISSN:
0021-9967
Resumen:
New neurons continuously differentiate within the otherwise mature retina of teleost
fish, both under normal conditions and in response to injury. We investigated the effects of
surgical injury and intraocular injection of neurotrophic factors on the mitotic rate of proliferative
inner nuclear layer cells (PINC). PINCare continually born in the inner nuclear layer
and then migrate to the outer nuclear layer (ONL). Surgical excision of a part of a retina
activates PINC mitotic activity near and far fromthe lesion. In the injured eye, up-regulation
of PINC cells is largest in the dorsonasal sector of the retina, regardless of the site of lesion.
Up-regulation extends even to the unlesioned contralateral eye, where it occurs in the same
dorsonasal sector. Intraocular injection of ciliary neurotrophic factor mimics the effect of
injury on PINC in the treated eye but not on the untreated contralateral retina. We searched
for the expression in PINC of Pax6, a transcription factor linked to retinal progenitor cells
and found that less than 0.5% of all PINC cells express it. Importantly, the number of
Pax6-expressing PINC does not change significantly in the retinas subjected to any of the
experimental manipulations tested. Under normal conditions, the default fate of PINC cells
is to migrate to the ONLand, likely, replenish the rod progenitor pool. PINCrespond to injury
(both surgical and light-dependent) by increasing their mitotic rate; this increase is long
lived, but there are no changes in the expression level of Pax6. PINC probably are a
heterogenous cell population that can be specified for ultimate, different purposes: creating
rod precursors, creating founder cells, creating cone precursors. Several fates are recognized
now, but others may also be possible.