Project description:Background: Substantial progress has been made in the identification of sequence elements that control mRNA splicing and the genetic variants in these elements that alter mRNA splicing (referred to as splicing quantitative trait loci -- sQTLs). Genetic variants that affect mRNA splicing in trans are harder to identify because their effects can be more subtle and diffuse, and the variants are not co-located with their targets. We carried out a transcriptome-wide analysis of the effects of a mutation in a ubiquitous splicing factor that causes retinitis pigmentosa (RP) on mRNA splicing, using exon microarrays. Results: Exon microarray data was generated from whole blood samples obtained from four individuals with a mutation in the splicing factor PRPF8 and four sibling controls. Although the mutation has no known phenotype in blood, there was evidence of widespread differences in splicing between cases and controls (affecting between 10\% and 25\% of exons). Most probesets with significantly different inclusion (defined as the expression intensity of the exon divided by the expression of the corresponding transcript) between cases and controls had higher inclusion in cases and corresponded to exons that were shorter than average, AT-rich, located towards the 5' end of the gene and flanked by long introns. Introns flanking affected probesets were particularly depleted for the shortest category of introns, associated with splicing via intron definition. Conclusions: Our results show that a mutation in a splicing factor, with a phenotype that is restricted to retinal tissue, acts as a trans-sQTL cluster in whole blood samples. Characteristics of the affected exons suggest that they are spliced co-transcriptionally and via exon definition. Eight samples consisting of four sibling pairs were analysed. One individual in each pair harboured an RP-causing mutation on the PRPF8 gene (cases). Unaffected siblings were used as controls.
Project description:Recessive retinitis pigmentosa (RP) is often caused by nonsense mutations that lead to low mRNA levels as a result of nonsense-mediated decay. Some RP genes are expressed at detectable levels in leukocytes as well as in the retina. We designed a microarray-based method to find recessive RP genes based on low lymphoblast mRNA expression levels Keywords: Recessive mutations; mRNA expression; nonsense mediated-decay; retinitis pigmentosa; lymphocyte; Affymetrix genechip Human Genome U133Plus2.0.
Project description:Retinitis pigmentosa (RP) is an inherited eye disease that causes progressive vision loss.To investigate the biological processes and molecular changes that occur in different cell types in the retinas in rd1 mice, a mouse model of retinitis pigmentosa, we performed single-cell RNA-seq to examine the transcriptomes of various retinal cells.
Project description:Background: Substantial progress has been made in the identification of sequence elements that control mRNA splicing and the genetic variants in these elements that alter mRNA splicing (referred to as splicing quantitative trait loci -- sQTLs). Genetic variants that affect mRNA splicing in trans are harder to identify because their effects can be more subtle and diffuse, and the variants are not co-located with their targets. We carried out a transcriptome-wide analysis of the effects of a mutation in a ubiquitous splicing factor that causes retinitis pigmentosa (RP) on mRNA splicing, using exon microarrays. Results: Exon microarray data was generated from whole blood samples obtained from four individuals with a mutation in the splicing factor PRPF8 and four sibling controls. Although the mutation has no known phenotype in blood, there was evidence of widespread differences in splicing between cases and controls (affecting between 10\% and 25\% of exons). Most probesets with significantly different inclusion (defined as the expression intensity of the exon divided by the expression of the corresponding transcript) between cases and controls had higher inclusion in cases and corresponded to exons that were shorter than average, AT-rich, located towards the 5' end of the gene and flanked by long introns. Introns flanking affected probesets were particularly depleted for the shortest category of introns, associated with splicing via intron definition. Conclusions: Our results show that a mutation in a splicing factor, with a phenotype that is restricted to retinal tissue, acts as a trans-sQTL cluster in whole blood samples. Characteristics of the affected exons suggest that they are spliced co-transcriptionally and via exon definition.
Project description:Mutations in the carboxy terminal of the core spliceosome factor PRPF8 cause autosomal dominant retinitis pigmentosa (RP) 13. Comprehensive cellular, biochemical, and molecular investigations of iPSC-derived retinal organoids, retinal pigment epithelium (RPE) and kidney organoids from four patients carrying the pathogenic PRPF8 RP type 13 c.6926A>C (p.H2309P) heterozygous missense mutation, revealed retinal tissue-specific effects including lower splicing specificity, ciliary abnormalities, altered apical-basal polarity, rod degeneration and loss of photoreceptors. The p.H2309P mutation affected the 5’ splice site recognition by PRPF8 of transcripts encoding ciliary proteins, altered spliceosome kinetics and organisation of nuclear speckles as well as PRPF8 binding to spliceosomal U6 snRNAs and snoRNAs, leading to accumulation of unspliced poly A+ mRNAs specifically in RPE cells and retinal organoids. Together these data provide the most comprehensive characterisation of splicing factor causing RP disease, providing molecular insights into the tissue specificity of pathomechanisms and informing future therapeutic approaches.
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:Mutations in pre-mRNA processing factors (PRPFs) cause autosomal dominant retinitis pigmentosa (RP), but it is unclear why mutations in ubiquitously expressed genes cause retinal disease. We have generated transcriptome profiles from RP11 (PRPF31-mutated) patient-derived retinal organoids and retinal pigment epithelium (RPE), as well as Prpf31+/- mouse tissues, which revealed that disrupted alternative splicing occurred for specific splicing programmes. Mis-splicing of genes encoding pre-mRNA splicing proteins was limited to patient-specific retinal cells and Prpf31+/- mouse retinae and RPE. Mis-splicing of genes implicated in ciliogenesis and cellular adhesion was associated with severe RPE defects that include disrupted apical-basal polarity, reduced trans-epithelial resistance and phagocytic capacity, and decreased cilia length and incidence. Disrupted cilia morphology also occurred in patient-derived photoreceptors, associated with progressive degeneration and cellular stress. In situ gene-editing of a pathogenic mutation rescued protein expression and key cellular phenotypes in RPE and photoreceptors, providing proof-of-concept for future therapeutic strategies.
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.