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Fig. 3

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Figures for Albadri et al., 2019
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Fig. 3

9-HSA Affects RPC Proliferation by Activating Notch Pathway

(A–D) Expression analyses of the Notch target gene her4.2 at 2 and 3 days postfertilization (dpf) in DMSO-treated (respectively, (A) and (C)) and 9-HSA-treated retinae (respectively, (B) and (D)) reveal an increase in the expression of her4.2 in retinae of 9-HSA-injected embryos. At 2 dpf, her4.2 transcripts could still be found in the central part of the retinal neuroepithelium of 9-HSA-injected embryos while already restricted to the forming ciliary marginal zone (CMZ) in the control embryos (A) and (B). At 3 dpf, the expression of her4.2 was expanded in the CMZ in 9-HSA-treated retinae in comparison to the DMSO-injected embryos (C) and (D).

(E–H) Inhibition of the Notch pathway by DAPT treatment rescues 9-HSA’s differentiation phenotype on retinal ganglion cells (RGCs) at 2 dpf. Tg(atoh7:gap-RFP) DMSO-injected (E) and (G) and 9-HSA-injected (F) and (H) embryos were respectively treated with either a DMSO control solution or with a DAPT supplemented solution. DMSO-injected embryos treated with DAPT presented a thicker RGC layer. RGCs formed rosettes (white arrow) and a thicker optic nerve (F). DAPT treatment of 9-HSA-injected embryos resulted in the rescue of RGC differentiation (H) (n = 6 retinae for each condition). The average thickness of the RGC layer size was quantified for all conditions and we found that DAPT treatment increase significantly RGC layer thickness regardless of 9-HSA injection (in (G) versus (H): 10.31 μm ± 0.1643 in n = 3 and 30.22 μm ± 1.586 in n = 4, p value: 0.001, unpaired Student’s t test).

(I–K”) (I–J’) Intraocular injections of 9-HSA lead to an increase in proliferation of RPCs in the central part of the tissue compared to DMSO-injected retinae. 1 dpf embryos were injected intraocularly with 9-HSA in one eye and DMSO in the other eye (in n = 10 retinae). The injections were followed by an EdU incorporation assay at 2 dpf, and the effect of 9-HSA local retinal treatment on RPC proliferation was assessed at 3 dpf. Compared to the DMSO-injected eyes where almost all cells were EdU negative in the differentiated central part of the retina, retinae injected with 9-HSA still presented a high number of EdU-positive cells in this part of the tissue (K)–(K”). Intraocular injection of 9-HSA and DMSO in the right (R) and left (L) eye, respectively, of 2 dpf embryos followed by an in situ hybridization on her4.2 at 3 dpf. 9-HSA ocular injection leads to a striking increase of her4.2 expression in the central right retina and an expansion of its expression domain in the CMZ (K’) in comparison to DMSO-control-injected left retina (K”) (in n = 20 injected embryos).

Scale bars, 50 μm in (A)–(I), (J), and (K’)–(K”); 20 μm in (I’) and (J’); and 100 μm in (K).

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Reprinted from Developmental Cell, 50(1), Albadri, S., Naso, F., Thauvin, M., Gauron, C., Parolin, C., Duroure, K., Vougny, J., Fiori, J., Boga, C., Vriz, S., Calonghi, N., Del Bene, F., Redox Signaling via Lipid Peroxidation Regulates Retinal Progenitor Cell Differentiation, 73-89.e6, Copyright (2019) with permission from Elsevier. Full text @ Dev. Cell