Increased H3K27 trimethylation contributes to cone survival in a mouse model of cone dystrophy
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE195895 | GEO | 2022/07/20
REPOSITORIES: GEO
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Project description:The macula of the retina has a high ratio of cones to rods and is critical for central vision and visual acuity. Macula degenerations affect vision the most and are incurable. Here we report the generation, transcriptome profiling, and functional validation of cone-enriched human retinal organoids differentiated from hESCs. Transcriptome profiling using bulk RNA-seq demonstrated that retinal differentiation in vitro recapitulated retinogenesis in vivo in the temporal expression of cell differentiation markers and retinal disease genes, as well as in mRNA alternative splicing. Single-cell RNA-seq of 8-month retinal organoids identified clusters of cone and rod photoreceptors and confirmed the cone enrichment initially revealed by immunostaining. Notably, comparisons of single-cell transcriptomes demonstrated the similarity between retinal organoids and human macula in cones and rods. Cones in retinal organoids exhibited electrophysiological functions. Collectively, we have established cone-enriched retinal organoids and a reference of transcriptomes that are rich resources for retinal studies.
2019-04-25 | GSE119274 | GEO
Project description:The loss of cone photoreceptor cells, which are critical for optimal daylight vision, have the great impact on vision during retinal degenerations. Retinal differentiation of human induced pluripotent stem cell (hiPSC) sources could provide a renewable source of cone photoreceptors towards developing a cone cell replacement therapy to treat blindness. Demonstration of comparable gene expression profiles between human foetal and stem cell-derived cones at equivalent stages is required to progress the cell transplantation approach into the patient, as it is hypothesised stem cell-derived cones are required to show high levels of developmental recapitulation of the in vivo generated cones. In this study, the AAV2/9.pR2.1.GFP reporter was used to specifically label L/M-opsin cone photoreceptors in human foetal retinal samples, obtained from the MRC-Wellcome Trust Human Developmental Biology Resource, at a range of developmental stages. The L/M-opsin cone population represent the majority cone cell types in the adult human retina and are the only photoreceptors present within the fovea. Using fluorescence activated cell sorting, L/M-opsin GFP+ cones and GFP- retinal populations, alongside total foetal retinal samples containing all retinal cell tytpes, were isolated and processed for bulk RNA sequencing and downstream comparative analysis. Using DESeq2 differential gene expression analyses, statistically significant genes enriched within the GFP+ human foetal LM-opsin cone populations were determined which led to the identification of a cone enriched gene signature of human L/M-opsin cone photoreceptors. The AAV2/9.pR2.1.GFP reporter was applied to hiPSC-derived retinal cultures to isolate and process cone-like cell populations for RNA sequencing using the same strategy developed within the human foetal retina. Applying the cone enriched gene signature to the transcriptome of hiPSC-derived GFP+ samples at equivalent developmental stages revealed some expression similarities in genes found to be enriched within the late foetal L/M-opsin cone photoreceptors. This analysis overall revealed an intermediate stage of cone differentiation was achieved within the hiPSC-derived samples and the comparison to human foetal L/M-opsin gene express profiles suggesting further differentiation of hiPSC-derived sample is required.
2018-04-20 | E-MTAB-6057 | biostudies-arrayexpress
Project description:Cone photoreceptors are the primary initiator of visual transduction in the human retina. Dysfunction or death of rod photoreceptors precedes cone loss in many retinal and macular degenerative diseases, suggesting a rod-dependent trophic support for cone survival. Rod differentiation and homeostasis are dependent on the basic motif leucine zipper transcription factor NRL. The loss of Nrl in mice (Nrl-/-) results in a retina with predominantly S-opsin containing cones that exhibit molecular and functional characteristics of WT cones. Here we report that Nrl-/- retina undergoes a rapid but transient period of degeneration in early adulthood, with cone apoptosis, retinal detachment, alterations in retinal vessel structure, and activation and translocation of retinal microglia. However, cone degeneration stabilizes by four months of age, resulting in a thinned but intact outer nuclear layer with residual cones expressing S- and M-opsins and a preserved photopic ERG. At this stage, microglia translocate back to the inner retina and reacquire a quiescent morphology. Gene profiling analysis during the period of transient degeneration reveals misregulation of stress response and inflammation genes, implying their involvement in cone death. The Nrl-/- retina illustrates the long-term viability of cones in the absence of rods and may serve as a model for elucidating mechanisms of cone homeostasis and degeneration that would be relevant to understanding diseases of the cone-dominant human macula. Targets were generated from a pair of retinas (one Nrl-/- mouse) per biological replicate. Four biological replicates were generated for each of the five aging timepoints (1, 2, 4, 6, and 10 months post natal).
2011-11-15 | E-GEOD-33674 | biostudies-arrayexpress
Project description:Cone photoreceptor cell death in inherited retinal diseases, such as Retinitis Pigmentosa (RP), leads to the loss of accurate and color vision and ultimately blindness. In RP, a vast number of mutations are affecting the structure and function of rod photoreceptors while cones remain mutation-free. Once majority of rods have degenerated cones are dying secondarily due to the increased oxidative stress, inflammation and loss of structural and nutritional support normally provided by rods. Here we demonstrated that secondary cone cell death in animal models for RP is governed by an increased activity of histone deacetylates (HDACs). A single intravitreal injection of an HDAC inhibitor at a late stage of the disease, when majority of rods have already degenerated, is sufficient to delay cone death and support long-term cone survival. Surviving cones are retaining functionality and are mediating light-driven ganglion cell responses. RNA-seq analysis of surviving cones demonstrated that HDAC inhibition affords multi-level protection trough regulation of different prosurvival pathways including MAPK, PI3K-AKT and autophagy. These study suggest a unique possibility for targeted pharmacological protection of both primary degenerating rods and mutation-free secondary dying cones and creates hope to maintain vision in RP patients independent of the disease stage.
2020-11-04 | GSE141601 | GEO
Project description:The macula of the retina has a high ratio of cones to rods and is critical for central vision and visual acuity. Here we report the generation, transcriptome profiling, and functional validation of single cells from cone-enriched human retinal organoids differentiated from hESCs. Single-cell RNA-seq of 8-month retinal organoids identified clusters of cone and rod photoreceptors and confirmed the cone enrichment initially revealed by immunostaining. Collectively, we have established cone-enriched retinal organoids and a reference of transcriptomes that are rich resources for retinal studies.
2019-04-25 | GSE119343 | GEO
Project description:Cone photoreceptors are the primary initiator of visual transduction in the human retina. Dysfunction or death of rod photoreceptors precedes cone loss in many retinal and macular degenerative diseases, suggesting a rod-dependent trophic support for cone survival. Rod differentiation and homeostasis are dependent on the basic motif leucine zipper transcription factor NRL. The loss of Nrl in mice (Nrl-/-) results in a retina with predominantly S-opsin containing cones that exhibit molecular and functional characteristics of WT cones. Here we report that Nrl-/- retina undergoes a rapid but transient period of degeneration in early adulthood, with cone apoptosis, retinal detachment, alterations in retinal vessel structure, and activation and translocation of retinal microglia. However, cone degeneration stabilizes by four months of age, resulting in a thinned but intact outer nuclear layer with residual cones expressing S- and M-opsins and a preserved photopic ERG. At this stage, microglia translocate back to the inner retina and reacquire a quiescent morphology. Gene profiling analysis during the period of transient degeneration reveals misregulation of stress response and inflammation genes, implying their involvement in cone death. The Nrl-/- retina illustrates the long-term viability of cones in the absence of rods and may serve as a model for elucidating mechanisms of cone homeostasis and degeneration that would be relevant to understanding diseases of the cone-dominant human macula.
2011-11-15 | GSE33674 | GEO
Project description:The mechanisms underlying specification of neuronal subtypes within the human nervous system are largely unknown. The blue/S, green/M and red/L cones of the retina enable high-acuity daytime and color vision. To determine the mechanism controlling S vs. L/M fates, we studied the differentiation of human retinal organoids. Organoids and retinas have similar distributions, expression profiles, and morphologies of cone subtypes. S cones are specified first, followed by L/M cones, and thyroid hormone signaling controls this temporal switch. Dynamic expression of thyroid hormone-degrading and activating proteins within the retina ensures low signaling early to specify S cones and high signaling late to produce L/M cones. This work establishes organoids as a model for determining mechanisms of human development with promising utility for therapeutics and vision repair.
2018-10-12 | GSE119320 | GEO
Project description:The outer segments of cones serve as light detectors for daylight color vision, and their dysfunction leads to human blindness conditions. We show that the cone-specific disruption of DiGeorge Syndrome Critical Region Gene 8 (DGCR8) in adult mice led to the loss of miRNAs and the loss of outer segments, resulting in photoreceptors with significantly reduced light responses. Using next-generation sequencing of RNA from isolated wild type P60 cones, we determine the most highly expressed miRNAs as candidates for controlling outer segment maintenance. The expression pattern of miRNAs was highly uneven, with a single miRNA, miR-182, representing 64% of all miRNA expressed in cones. Re-expression of miR-182 and miR-183 (third most abundant miRNA) prevented outer segment loss. These miRNAs were also necessary and sufficient for the formation of inner segments, connecting cilia and short outer segments, as well as light responses in stem-cell-derived retinal cultures. Our results show that miR-182- and miR-183-regulated pathways are necessary for cone outer segment maintenance in vivo and functional outer segment formation in vitro. microRNA profile in cone photoreceptors from P60 D4-cre/Ai9 tdTomato mice representing wild type control.
2014-06-20 | E-GEOD-58500 | biostudies-arrayexpress
Project description:Cone photoreceptors are specialised sensory retinal neurons responsible for photopic vision, colour perception and visual acuity. Retinal degenerative diseases are a heterogeneous group of eye diseases in which the most severe vision loss typically arises from cone photoreceptor dysfunction or degeneration. Establishing a method to purify cone photoreceptors from retinal tissue can accelerate the identification of key molecular determinants that underlie cone photoreceptor development, survival and function. The work herein describes a new method to purify enhanced green fluorescent protein (EGFP)-labelled cone photoreceptors from adult retina of Tg(3.2TαCP:EGFP) zebrafish. Electropherograms confirmed downstream isolation of high-quality RNA with RNA integrity number (RIN) >7.6 and RNA concentration >5.7 ng/µl obtained from both populations. Reverse Transcriptase-PCR (RT-PCR) confirmed that the EGFP-positive cell populations express known genetic markers of cone photoreceptors that were not expressed in the EGFP-negative cell population. This work is an important step towards the identification of cone photoreceptor-enriched genes, protein and signalling networks responsible for their development, survival and function. In addition, this advancement facilitates the identification of novel candidate genes for inherited human blindness. In order to analyse and sort samples by flow cytometry, values for FSC and SSC were displayed in a logarithmic scale, as this is normally the default starting display. This allowed for the identification of different sub-populations of cells present in the retina, which were mixed with unwanted cell debris and cell fragments. Since there were multiple cell populations, different levels of auto-fluorescence were thus successfully detected. It was therefore important to change the strategy and display side scatter and fluorescence characteristics of control and EGFP samples, which ultimately allowed the identification of the extremely well-defined population of EGFP-cone photoreceptors. This improved sorting process minimised RNA degradation. The purified EGFP+ cone photoreceptors represent ~5% of the original dissociated population, which is consistent with humans, wherein the total number of cones (6 million) in the retina is approximately 20 times the one of rods (120 million) (Williamson and Cummins 1983). This work allows high-quality RNA to be obtained from sorted-adult cone photoreceptors. RNA integrity is assessed via 28S and 18S rRNA (Imbeaud et al 2005), and our electropherogram results demonstrate production of high-quality RNA with two clearly visible ribosomal peaks (28S and 18S) from EGFP-sorted cones. In addition, the RNA Integrity Number (RIN), an algorithm for assigning integrity values to RNA based on 28S to 18S rRNA ratios (Sambrook et al 1989; Imbeaud et al 2005; Schroeder et al 2006), had a value of 7.6, higher than the minimum-required 7.0. RNA yields of 5.7 ng/µl were relatively high and sufficient for downstream profiling. RT-PCR confirmed expression of the cone specific gene gnat2, and promoter fragment TαC, but not the retinal pigment epithelium specific gene rpe65 in flow cytometry-sorted GFP-positive photoreceptors (GFP+ cells). rpe65 was neither present in flow cytometry-sorted GFP-negative cones (GFP- cells) as this gene is only expressed in the retinal pigment epithelium (RPE). This study therefore permits the identification of cone photoreceptor-enriched genes, protein and signalling networks responsible for their development, survival and function. In addition, this advancement facilitates the identification of novel candidate genes for inherited human blindness.
2017-10-31 | GSE86155 | GEO
Project description:The Unfolded Protein Response is a conserved intracellular signal transduction mechanism that maintains endoplasmic reticulum homeostasis and may contribute to the pathogenesis and progression of human diseases associated with ER stress. Genetic mutations in the UPR regulator, ATF6, lead to vision loss in heritable retinal diseases. Our prior studies found that disease mutations disrupt ATF6 function, but the pathomechanism by which loss of ATF6 activity causes vision loss in people is unknown. To investigate this, we developed retinal organoids from patient iPSCs carrying ATF6 disease mutations and from hESCs bearing CRISPR-edited ATF6 null alleles. Unexpectedly, we found that retinal organoids lacking functional ATF6 failed to form cone photoreceptors while rod photoreceptors were unaffected. We used adaptive optics imaging of the retinas in patients with ATF6 mutations and saw pronounced loss of cones and preservation of rods that closely mirrored our in vitro organoid phenotypes. Last, we found that a small molecule proteostasis agonist partially restored cone photoreceptor outer segment formation and gene expression in ATF6 mutant retinal organoids. Our results reveal a surprising and novel function for ATF6 in human cone photoreceptor development. Our findings identify a potential therapeutic strategy for patients based on small molecule reprogramming of the proteostasis network in the retina. Our study suggests that the UPR guides intrinsic developmental processes in specialized metazoan cell types in addition to its role in responding to extrinsic pathologic events.
2021-06-25 | GSE153302 | GEO