Cone-Enriched Cultures from the Retina of Chicken Embryos to Study Rod to Cone Cellular Interactions

Abstract

Human daytime vision relies on the function of cone photoreceptors at the center of the retina, the fovea. Patients suffering from the most prevalent form of inherited retinal degeneration, retinitis pigmentosa, lose night vision because of mutation driven loss of rod photoreceptors, a phenomenon followed by a progressive loss of function and death of cones leading to blindness. Geneticists have identified many genes with mutations causing this disease, but the first mutations identified questioned the mechanisms of secondary cone degeneration and how a dominant mutation in the rhodopsin gene encoding for the visual pigment expressed exclusively in rods can trigger cone degeneration. This result of transplantations in a genetic model of the disease led to the concept of cell interactions between rods and cones and of non-cell autonomous degeneration of cones in all genetic forms of retinitis pigmentosa. Cones comprise 5% of all photoreceptors in humans and only 3% in the mouse, so their study is difficult in these species, but cones outnumber rods in bird species. We have adapted 96-well plates to culture retinal precursors from the retina of chicken embryos at stage 29 of their development. In these primary cultures, cones represent 80% of the cells after in vitro differentiation. The cells degenerate over a period of one week in the absence of serum. Here, we describe the methods and its standardization. This cone-enriched culture system was used to identify the epithelium-derived cone viability factor (EdCVF) by high content screening of a rat retinal pigmented epithelium normalized cDNA library. Recombinant EdCVF prevents the degeneration of the cones.

The Emergence of the Metabolic Signaling of the Nucleoredoxin-like Genes during Evolution

“…The Nxnl1 gene was identified by high-content screening of a retinal expression library on a cone-enriched culture system through the activity of its product with intron retention, the rodderived cone viability factor (RdCVF) (Leveillard et al, 2004;Millet-Puel et al, 2021). Splicing of this unique intron produces the thioredoxin-related protein RdCVFL, which protects photoreceptors against damage caused by oxidation of cysteines in proteins, such as the microtubule-associated protein τ (TAU) (Cronin et al, 2010;Elachouri et al, 2015;Fridlich et al, 2009).…”

Eye-mimicked neural network composed of photosensitive neural spheroids with human photoreceptors

“…10 However, in vitro primary cultures of photoreceptor cells and RGCs are limited. [11][12][13] In recent years, retinal organoids have been developed that mimic the retinal structure. 14,15 Nevertheless, it is necessary to cut previously formed retinal organoids to develop axons from RGCs.…”