Abstract
Purpose :
Retinal degenerative diseases, like age-related macular degeneration, present a complex pathology, characterized by photoreceptor loss and glial pathology. However, its recapitulation is limited in preclinical models, which are required to better understand retinal degeneration and to develop therapies. Recently, Völkner et al. (2022) showed that the combined application of Heparin-binding EGF-like growth factor (HBEGF) and Tumor necrosis factor-a (TNF-a; H+T) induces complex retinal pathology in human iPSC-derived retinal organoids. Here, we assess whether these factors induce a complex retinal pathology also in the adult mouse eye, and its effect on photoreceptor transplantation.
Methods :
C57BL/6j mice at 16 weeks of age received intravitreal injections of HBEGF and TNF-a separately or combined at different concentrations for 2, 3, or 4 days. Eyes were analyzed 4 or 30 days post treatment by TUNEL assay and IHC using antibodies against photoreceptors and Muller glia. Additionally, H+T-injected mice received a subretinal transplantation of day 200 photoreceptors, enriched from human iPSC-derived retinal organoids (Crx-mCherry iPSCs line). Retinas were analyzed 3 weeks later.
Results :
Major retinal foldings, cell death in the outer nuclear layer (ONL), ectopic cells, GFAP up-regulation and SOX2 migration was observed after 4 days of HBEGF (200 ng/µl), TNF-a (50 ng/µl) and H+T injections, with the pathologic changes persisting for at least 30 days. Photoreceptor degeneration was present after 2 days of H+T injection at standard concentration and 3 days of H+T diluted 1:10. Upon transplantation of human photoreceptors, increased Müller glia-graft interactions were observed in H+T in comparison to sham-injected mice.
Conclusions :
Overall, H+T injections rapidly induce a complex retinal pathology phenotype in adult mice, with the phenotype depending on injection number and concentration. While the mechanism of photoreceptor degeneration has yet to be studied, this model provides a complex retinal pathology which might help in the identification of molecular targets to prevent retinal degeneration. Furthermore, the H+T model appears to facilitate host Müller glia-donor photoreceptor interactions, relevant for the understanding of photoreceptor transplant integration and the role of Müller glia for structural graft incorporation into the diseased retina.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.