Eye Development and Retinogenesis

Abstract

SUMMARYThree embryonic tissue sources-the neural ectoderm, the surface ectoderm, and the periocular mesenchyme-contribute to the formation of the mammalian eye. For this reason, the developing eye has presented an invaluable system for studying the interactions among cells and, more recently, genes, in specifying cell fate. This article describes how the eye primordium is specified in the anterior neural plate by four eye field transcription factors and how the optic vesicle becomes regionalized into three distinct tissue types. Specific attention is given to how cross talk between the optic vesicle and surface ectoderm contributes to lens and optic cup formation. This article also describes how signaling networks and cell movements set up axes in the optic cup and establish the multiple cell fates important for vision. How multipotent retinal progenitor cells give rise to the six neuronal and one glial cell type in the mature retina is also explained. Finally, the history and progress of cellular therapeutics for the treatment of degenerative eye disease is outlined. Throughout this article, special attention is given to how disruption of gene function causes ocular malformation in humans. Indeed, the accessibility of the eye has contributed much to our understanding of the basic processes involved in mammalian development.

Cysteine‐rich protein 61 (CCN1) and connective tissue growth factor (CCN2) at the crosshairs of ocular neovascular and fibrovascular disease therapy

“…The mammalian eye derives embryologically from three embryonic tissue sources, the neural ectoderm, the surface ectoderm, and the periocular mesenchyme (Heavner and Pevny 2012). Interestingly, during development, the inner retinal vasculature is absent, and oxygenation of the retina is provided uniquely by choroidal and hyaloid vessels (Zhu et al 2000).…”

Stem cell therapies for retinal diseases: recapitulating development to replace degenerated cells

“…It is also possible that additional factors not yet identified, and potentially specific to human retinal development, will aid neural retinal and RPE differentiation. and the ganglion cell layer (GCL) consisting of long projection RGCs (Heavner and Pevny, 2012). The retina processes visual signals originating in photoreceptors and sends output to the brain via the RGC axons that run in the optic nerve to the optic chiasm where they partially decussate, parsing to run in the contra-and ipsilateral optic tracts.…”

“…The summary we present here is a general overview formed from studies in vertebrates, and focuses on those events that are key to the development and specification of the cell types most affected in human retinal disease. For a more detailed description of retinal development, we refer the reader to two review articles (Centanin and Wittbrodt, 2014;Heavner and Pevny, 2012).…”

“…Subsequent optic cup formation is the result of consecutive and reciprocal inductive interactions between the neuroepithelium of the ventral forebrain, surface ectoderm, and extraocular mesenchyme, which is both neural crest and mesoderm derived (Adler and Canto-Soler, 2007;Fuhrmann, 2010). As the evaginating optic vesicle makes contact with the mesenchyme and the ectoderm, it divides into a distal domain and the more proximal/ ventral domains (Heavner and Pevny, 2012) (Fig. 1).…”

“…Thus, a bilayered optic cup is formed. The most proximal/ventral domain of the optic vesicle narrows into the optic stalk, the cavity filling with RGC axons to create the optic nerve at later stages of retinal development (Fuhrmann, 2010;Heavner and Pevny, 2012;Molotkov et al, 2006) (Fig. 1).…”