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Harding, E. G.

Publications and source records attributed to Harding, E. G..

3 recordsLinked to original sources

A genome-wide in vivo CRISPR screen identifies neuroprotective strategies in the mouse and human retina

Retinitis pigmentosa (RP) is a genetically diverse blinding disorder lacking broadly effective therapies. We performed a genome-wide in vivo CRISPR knockout screen in mice carrying the P23H rhodopsin mutation (the most common cause of autosomal dominant RP in the United States) to systematically identify neuroprotective genes. We discovered multiple knockouts that accelerated rod photoreceptor loss, validated top candidates, and showed that overexpressing two genes--UFD1 and UXT--preserved rods and cones, maintained retinal function, and improved visual behaviors. To accelerate translation, we developed a human P23H RP model in adult retinal explants, recreating key disease features. UFD1 and UXT augmentation prevented photoreceptor loss in human P23H retinas. Our findings establish a pipeline for systematic identification and translational testing of neuroprotective genes in mouse and human RP models, provide a novel set of validated candidate genes, and underscore the therapeutic promise of UFD1 and UXT as mutation-agnostic strategies to preserve vision.

neuroscience↗

Active DNA demethylation is upstream of rod-photoreceptor fate determination and required for retinal development

Retinal cell fate specification from multipotent retinal progenitors is governed by dynamic changes in chromatin structure and gene expression. Methylation at cytosines in DNA (5mC) is actively regulated for proper control of gene expression and chromatin architecture. Numerous genes display active DNA demethylation across retinal development; a process that requires oxidation of 5mC to 5-hydroxymethylcytosine (5hmC) and is controlled by the ten-eleven translocation methylcytosine dioxygenase (TET) enzymes. Using an allelic series of conditional TET enzyme mutants, we determine that DNA demethylation is required upstream of NRL and NR2E3 expression for the establishment of rod-photoreceptor fate. Using histological, behavioral, transcriptomic, and base-pair resolution DNA methylation analyses, we establish that inhibition of active DNA demethylation results in global changes in gene expression and methylation patterns that prevent photoreceptor precursors from adopting a rod-photoreceptor fate, instead producing a retina in which all photoreceptors specify as cones. Our results establish the TET enzymes and DNA demethylation as critical regulators of retinal development and cell fate specification, elucidating a novel mechanism required for the specification of rod-photoreceptors.

developmental biology↗

Age-related dysregulation of the retinal transcriptome in African turquoise killifish

Age-related vision loss caused by retinal neurodegenerative pathologies is becoming more prevalent in our ageing society. To understand the physiological and molecular impact of ageing on retinal homeostasis, we used the short-lived African turquoise killifish, a model known to naturally develop central nervous system (CNS) ageing hallmarks and vision loss. Bulk and single-cell RNA-sequencing (scRNA-seq) of three age groups (6-, 12-, and 18-week-old) identified transcriptional ageing fingerprints in the killifish retina, unveiling pathways also identified in the aged brain, including oxidative stress, gliosis, and inflammageing. These findings were comparable to observations in ageing mouse retina. Additionally, transcriptional changes in genes related to retinal diseases, such as glaucoma and age-related macular degeneration, were observed. The cellular heterogeneity in the killifish retina was characterised, confirming the presence of all typical vertebrate retinal cell types. Data integration from age-matched samples between the bulk and scRNA-seq experiments revealed a loss of cellular specificity in gene expression upon ageing, suggesting potential disruption in transcriptional homeostasis. Differential expression analysis within the identified cell types highlighted the role of glial/immune cells as important stress regulators during ageing. Our work emphasises the value of the fast-ageing killifish in elucidating molecular signatures in age-associated retinal disease and vision decline. This study contributes to the understanding of how age-related changes in molecular pathways may impact CNS health, providing insights that may inform future therapeutic strategies for age-related pathologies. HighlightsO_LIThe aged killifish retina displays several ageing hallmarks, such as oxidative stress, gliosis and inflammageing, at the transcriptome level. C_LIO_LIRisk genes for neurodegenerative disorders show dysregulation in the old killifish retina. C_LIO_LIAll vertebrate retinal cell types are present in the killifish retina. C_LIO_LITranscriptional dysregulation in the aged killifish retina is observed across cell types. C_LI

neuroscience↗