A Hidden Retinal Regenerative Capacity from the C Ciliary Margin is Reactivated In Vitro, that is Accompanied by Down‐regulation of Butyrylcholinesterase

Abstract

The chicken retina has a capacity to regenerate in vivo, which is restricted up to embryonic day 4 (E4). Here we test the proliferative patterns of dissociated chicken cells from the centre retina or the ciliary margin, including pigmented cells, after their transfer into rotation culture. For central cells in culture, the uptake of [3H]thymidine after a short initial rise decreases similarly to their in ovo counterparts. In contrast, marginal cells that have been shown to regenerate up to E9 into retinotypic stratospheroids re-enter a novel and long-lasting phase of in vitro cell division. We have shown previously that cell types of all nuclear layers are produced. Both observations taken together indicate a pronounced self-renewal of multipotent stem cells. Molecularly, the enzyme butyrylcholinesterase, which in other systems has been shown to mark transitory neuronal cells between proliferation and differentiation, is strongly expressed at the ciliary margin over most of the embryonic period. After these cells are transferred into rotation culture, butyrylcholinesterase is down-regulated. Concomitantly, the neuronal differentiation marker acetylcholinesterase increases. We conclude that the regenerative capacity of the chick retina is not lost at E4, but rather remains hidden in the chicken ciliary margin, since it can be reactivated in vitro at least up to E9. We suggest that butyrylcholinesterase may be linked to the regulation of stem cell activity.

Fibroblast growth factor–hedgehog interdependence during retina regeneration

“…In fact, these progenitors are able to give rise to new neurons in an injured retina mouse model . In the embryonic chick, isolated cells from the anterior region of E9 eyes retain the ability to proliferate in vitro, and when incubated in rotation culture assays, they form laminar structures containing all nuclear retinal cell types (Willbold and Layer, 1992). Consistent with these reports, we have observed that the chick can regenerate the retina from the CB/CMZ in vivo until at least E5 when stimulated with FGF2.…”

The hedgehog pathway is a modulator of retina regeneration

“…These cells have been shown to have activity up to E9 (Willbold and Layer, 1992). The regenerated retina forms with normal polarity and can associate with adjacent RPE that did not undergo transdifferentiation (Coulombre and Coulombre, 1965;Park and Hollenberg, 1991).…”

Light-Dark and Circadian Melatonin Rhythms Are Established de novo in Re-Aggregates of the Embryonic Chicken Retina

“…As with re-aggregation approaches of other tissues [Heller, 1993;Schmid et al, 1993;Müller-Klieser, 1997;Seigel, 1999;Pardo and Honegger, 2000], embryonic cells from the functional part of the retina are also completely dissociated. The dispersed cells, including pluri-potent retinal cells [Willbold and Layer, 1992], re-aggregate into spheres, whereby they continue to proliferate and differentiate into rosetted spheroids. Eventually, most cell types are present and can be found in multi-centric laminated areas with an inverse polarity.…”