Project description:Retinitis Pigmentosa (RP) is a progressive retinal degeneration in which the retina loses nearly all of its photoreceptor cells and undergoes major structural changes. Little is known regarding the role the resident glia, the MM-CM-<ller glia, play in the progression of the disease. Here we define gene expression changes in MM-CM-<ller glial cells (MGCs) from two different mouse models of RP, the retinal degeneration 1 (rd1) and rhodopsin knock-out (Rhod-ko) models. The RNA repertoire of 28 single MGCs was comprehensively profiled, and a comparison was made between MGC from wild type (WT) and mutant retinas. Two time points were chosen for analysis, one at the peak of rod photoreceptor death and one during the period of cone photoreceptor death. MGCs have been shown to respond to retinal degeneration by undergoing gliosis, a process marked by the upregulation of GFAP. In this data, many additional transcripts were found to change. These can be placed into functional clusters, such as retinal remodeling, stress response, and immune related response. It is noteworthy that a high degree of heterogeneity among the individual cells was observed, possibly due to their different spatial proximities to dying cells, and/or inherent heterogeneity among MGCs. Retinas were dissociated and single Muller Glial Cells were picked under a dissecting microscope using a micropipette based on their distinct morphological shape. Single cell cDNAs were generated and genome wide profiles were obtained by hybridization to Affymetrix 430 2.0 microarrays. Data was normalized using MAS5.0 software. A total of 28 Muller Glial Cells were analyzed and confirmed post hoc by expression of known marker genes.
Project description:Retinitis pigmentosa (RP) is an irreversible and inherited retinopathy. RPGR mutations are the most common causes of this disease. It remains challenging to decipher the mechanism of RPGR mutation because of the lack of appropriate study models. The substitution of patient-specific diseased retina without ethical restrictions is desired and iPSC-derived 3D retina is the best choice. In our experiment, we generated iPSCs from one RP patient with 2-bp frameshift mutation in the exon14 of RPGR gene, which were differentiated into retinal organoids. Also we generated iPSCs from a normal control and differentiated those control-iPSCs into healthy retinal organoids. Samples of patient- and control-retinal organoids at W0, W7, W13 (two replicates), W18 (two replicates) and W22 (two replicates for patient) were collected for RNA-seq. Corrected-iPSC were derived from CRISPR/Cas9-mediated gene correction. Then we collected the corrected-iPSC derived retinal organoids at W0, W7, W13 (two replicates), W18 (two replicates) and W22 (two replicates) for RNA-seq. Through the RNA-seq data, we demonstrate that patient-specific iPSC-dervied 3D retinae can recapitulate disease progress of Retinitis Pigmentosa through presenting defects in photoreceptors' gene profile. CRISPR/Cas9-mediated gene correction can rescue photoreceptor gene profile. Those transcriptome are consistent with the phenotype and function.
Project description:Retinitis Pigmentosa is a group of inherited eye disorders characterized by progressive degeneration of photoreceptor cells in the retina, leading to vision loss and eventual blindness. One of the known genetic mutations associated with RP is the c.6926A>C mutation in the RPE (retinal pigment epithelium) cells. The dataset involves multiple experimental approaches and cell types, providing a comprehensive understanding of the disease and potential corrective strategies.
Project description:Single-cell RNA-seq of mouse WT retinas and two Nr2e3 mutant retinas, ∆27 and ∆E8 (containing a 27 nucleotide in-frame deletion or a complete exon 8 deletion, respectively). The ∆27 retinas were used as a model for enhanced S-cone syndrome phenotype in humans, while the ∆E8 retinas show a progressive retinal degeneration similar to human retinitis pigmentosa patients. This data was used to explore the role of Nr2e3 in cone and rod photoreceptor differentiation.
Project description:Photoreceptor loss is a leading cause of blindness, but mechanisms underlying photoreceptor degeneration are not well understood. Treatment strategies would benefit from an improved understanding of gene-expression patterns directing photoreceptor development, as many genes are implicated in both development and degeneration. Neural retina leucine zipper (NRL) is critical for rod photoreceptor genesis and degeneration, with NRL mutations known to cause enhanced S-cone syndrome and retinitis pigmentosa. While murine Nrl loss has been characterized, studies of human NRL can identify important insights for human retinal disease. Here we utilized human organoid models of retinal development to molecularly define developmental alterations in a human model of NRL loss. Consistent with the function of NRL in rod fate specification, human retinal organoids lacking NRL develop S-opsin dominant photoreceptor populations. We report generation of two distinct S-opsin expressing populations in NRL null retinal organoids and identify MEF2C as a candidate regulator of cone development.
Project description:Photoreceptor cell degeneration is a major cause of blindness and a considerable health burden during aging but effective therapeutic or preventive strategies have not so far become commercially available. Here we show in mouse models that signaling through the tyrosine kinase receptor KIT protects photoreceptor cells against both light-induced and inherited retinal degeneration. Upon light damage, photoreceptor cells upregulate Kit ligand (KITL) and activate KIT signaling, which in turn induces nuclear accumulation of the transcription factor NRF2 and stimulates the expression of the antioxidant gene Hmox1. Conversely, a viable Kit mutation promotes light-induced photoreceptor damage, which is reversed by experimental expression of Hmox1. Furthermore, overexpression of KITL from a viral AAV8 vector prevents photoreceptor cell death and partially restores retinal function after light damage or in genetic models of human retinitis pigmentosa. Hence, application of KITL may provide a novel therapeutic avenue for prevention or treatment of retinal degeneration
Project description:Retinitis pigmentosa (RP) and Leber congenital amaurosis are inherited retinal dystrophies caused by mutations in, among others, the Crumbs homologue 1 (CRB1) gene. CRB1 is required for organizing apical-basal polarity and adhesion between photoreceptors and Müller glial cells. Using human CRB1 patient induced pluripotent stem cells from RP patients we derived CRB1 retinal organoids, with diminished expression of variant CRB1 protein with immunohistochemical analysis. Single cell RNA-sequencing revealed impact on, among others, the endosomal pathway and cell adhesion and migration in CRB1 patient derived retinal organoids compared to isogenic controls. Adeno-associated viral (AAV) vector-mediated hCRB2 or hCRB1 gene augmentation in Müller glial and photoreceptor cells partially restored the histological and differentially expressed genes phenotype. Altogether, we show proof-of-concept that AAV.hCRB1 or AAV.hCRB2 treatment improved the phenotype of CRB1 patient derived retinal organoids, providing essential information for future gene therapy approaches for patients with mutations in the CRB1 gene.
Project description:Primary and secondary cone photoreceptor cell death in retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, leads to severe vision impairment and blindness. Regardless of the fact that protection of cone photoreceptor cells under stress conditions, such as retinal degenerative diseases, is crucial for maintaining vision, the underlying molecular mechanisms are unclear. Here, we investigated the function of the deubiquitinase Otud7b/Cezanne in the retina. We identified that Otud7b is predominantly expressed in photoreceptor cells in the mouse retina. While the ablation of Otud7b did not cause a significant defect in development and maturation of the mouse retina, Otud7b‒/‒ mice subjected to light-induced damage, which is one of the dry age-related macular degeneration models, exhibited increased cone photoreceptor degeneration. In addition, Otud7b deficiency in Mak‒/‒ mice, a retinitis pigmentosa mouse model, resulted in further cone photoreceptor degeneration. Moreover, neuronal cells deficient in Otud7b were susceptible to serum starvation, resulting in cell death. We found that NF-κB activity is increased in the Otud7b‒/‒ retinas exposed to light by RNA-sequencing analysis. Luciferase reporter assay also demonstrated increased NF-κB activation in Otud7b-deficient neuronal cells under stress. The neuronal cell death resulting from Otud7b deficiency was suppressed through the inhibition of NF-κB. Furthermore, we observed that inhibition of NF-κB attenuated cone photoreceptor degeneration in the light-exposed Otud7b‒/‒ retina. Together, the current study suggests that Otud7b deubiquitinase protects cone photoreceptor cells under stress conditions by modulating the NF-κB activity.
Project description:Neuronal plasticity of the inner retina has been observed in response to photoreceptor degeneration. Typically, this phenomenon has been considered maladaptive and may preclude vision restoration in the blind. However, several recent studies utilizing triggered photoreceptor ablation have shown adaptive responses in bipolar cell dendrites expected to support normal vision. Whether such homeostatic plasticity occurs during progressive photoreceptor degenerative disease to help maintain normal visual behavior is unknown. We addressed these issues in an established mouse model of Retinitis Pigmentosa caused by the P23H mutation in rhodopsin. We show robust modulation of the retinal transcriptomic network reminiscent of the neurodevelopmental state as well as potentiation of rod – rod bipolar cell signaling following rod photoreceptor degeneration. Additionally, we found highly sensitive night vision in P23H mice even when more than half of the rod photoreceptors were lost. The results implicate retinal adaptation leading to persistent visual function during photoreceptor degenerative disease.
Project description:Neuronal plasticity of the inner retina has been observed in response to photoreceptor degeneration. Typically, this phenomenon has been considered maladaptive and may preclude vision restoration in the blind. However, several recent studies utilizing triggered photoreceptor ablation have shown adaptive responses in bipolar cell dendrites expected to support normal vision. Whether such homeostatic plasticity occurs during progressive photoreceptor degenerative disease to help maintain normal visual behavior is unknown. We addressed these issues in an established mouse model of Retinitis Pigmentosa caused by the P23H mutation in rhodopsin. We show robust modulation of the retinal transcriptomic network reminiscent of the neurodevelopmental state as well as potentiation of rod – rod bipolar cell signaling following rod photoreceptor degeneration. Additionally, we found highly sensitive night vision in P23H mice even when more than half of the rod photoreceptors were lost. The results implicate retinal adaptation leading to persistent visual function during photoreceptor degenerative disease.