Cell death in the developing vertebrate retina

Abstract

Programmed cell death occurs naturally, as a physiological process, during the embryonic development of multicellular organisms. In the retina, which belongs to the central nervous system, at least two phases of cell death have been reported to occur during development. An early phase takes place concomitant with the processes of neurogenesis, cell migration and cell differentiation. A later phase affecting mainly neurons occurs when connections are established and synapses are formed, resulting in selective elimination of inappropriate connections. This pattern of cell death in the developing retina is common among different vertebrates. However, the timing and magnitude of retinal cell death varies among species. In addition, a precise regulation of apoptosis during retinal development has been described. Factors such as neurotrophins, among many others, and electrical activity influence the survival of retinal cells during the course of development. In this paper, we present a summary of these different aspects of programmed cell death during retinal development, and examine how these differ among different species.

BMP signaling mediates stem/progenitor cell-induced retina regeneration

“…However, the low level of pAKT in untreated E11 CM explants suggest other mechanisms work with BMP to regulate this arm of the FGF pathway. This finding is not surprising because apoptosis normally occurs during this stage of retina development (23).…”

Multiple death pathways in retina-derived 661W cells following growth factor deprivation: crosstalk between caspases and calpains

“…1 The retina, as a part of the CNS, also undergoes a period of developmental apoptosis that allows adjustment of the final cell numbers, as well as stratification and proper connectivity among the different neuronal types. In this particular tissue, two waves of apoptotic cell death have been reported to occur, the first one coincident with the onset of cytogenesis/migration and the second one with synaptogenesis (for a review, see Vecino et al 2 ). Specifically, cone photoreceptors become postmitotic in the embryonic period but it is not until the second postnatal week that they reach their final position in the retina and maturation of the synaptic terminals takes place.…”

Retinal ganglion cells: dying to survive

“…Necrotic cells swell, with rupture of intracellular organelles, disruption of the lysosomal and plasma membranes and result in generalised tissue inflammation. However, these two forms of cell death are not necessarily mutually exclusive and may be viewed as occupying opposite ends of the same spectrum (Vecino et al, 2004, Spalding et al, 2005. Indeed there is growing evidence, as reported in this laboratory amongst others, of varying levels of cross talk between different death mediators, implying an ability to switch from one death mode to another.…”