Safety and Tolerability of RPE Stem Cell-Derived RPE (RPESC-RPE) Implantation in Patients With Dry Age-Related Macular Degeneration (AMD): Early Low Dose Clinical Outcomes

Document Type

Conference Proceeding

Publication Date

5-2025

Publication Title

Investigative Ophthalmology and Visual Science

Abstract

Purpose : The regulation of cell fate specification in the developing retina is governed by dynamic epigenetics in control of gene regulatory networks. DNA methylation is actively controlled during development by methylation writers (DNA methyltransferases - DNMTs) and erasers (ten-eleven translocation (TET) methylcytosine dioxygenases) for proper control of gene expression patterns. Previous DNA methylation profiling has implicated active demethylation in control of photoreceptor fate specification and phototransduction; however, the requirement of DNA demethylation for proper mammalian retinal development is yet to be assessed.

Methods : To determine the significance of DNA demethylation across retinal development, we generated an allelic series of conditional mouse mutants, removing TET enzyme expression within the developing retina using floxed mouse alleles for Tet1, Tet2, and Tet3 with the Chx10-Cre-GFP transgene. We performed histological, visual function testing, transcriptomic, and epigenomic profiling to determine the significance of TET enzymes and DNA demethylation during mouse retinal development.

Results : Histological analyses and visual function testing established a requirement for both Tet2 and Tet3 for proper retinal development and visual function. Although most major cell fates were specified properly, we observed that loss of the TET enzymes and DNA demethylation resulted in retinas with all photoreceptors specifying as cones. Transcriptomic analyses, in both bulk RNAseq and single-nucleus RNAseq, highlighted an up-regulation of cone-enriched transcripts at the expense of rod transcripts, including loss of Nrl and Nr2e3 expression. Base-pair resolution methylation profiling of 5mC and 5hmC highlights the global changes in DNA methylation patterns after loss of the TET enzymes, resulting in failure to initiate rod gene regulatory networks resulting from maintained methylation at rod-promoting gene loci.

Conclusions : Our results highlight the requirement of active, TET enzyme-dependent DNA demethylation in photoreceptor precursor cells for establishment of rod fate specification and proper control of visual function.

Volume

66

Issue

8

First Page

2701

Comments

Association for Research in Vision and Ophthalmology ARVO Annual Meeting, May 4-8, 2025, Salt Lake City, UT

Last Page

2701

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