Retinal organoids with X-linked retinoschisis RS1 (E72K) mutation exhibit a photoreceptor developmental delay and are rescued by gene augmentation therapy.

BACKGROUND: X-linked juvenile retinoschisis (XLRS) is an inherited disease caused by RS1 gene mutation, which leads to retinal splitting and visual impairment. The mechanism of RS1-associated retinal degeneration is not fully understood. Besides, animal models of XLRS have limitations in the study of XLRS. Here, we used human induced pluripotent stem cell (hiPSC)-derived retinal organoids (ROs) to investigate the disease mechanisms and potential treatments for XLRS. METHODS: hiPSCs reprogrammed from peripheral blood mononuclear cells of two RS1 mutant (E72K) XLRS patients were differentiated into ROs. Subsequently, we explored whether RS1 mutation could affect RO development and explore the effectiveness of RS1 gene augmentation therapy. RESULTS: ROs derived from RS1 (E72K) mutation hiPSCs exhibited a developmental delay in the photoreceptor, retinoschisin (RS1) deficiency, and altered spontaneous activity compared with control ROs. Furthermore, the delays in development were associated with decreased expression of rod-specific precursor markers (NRL) and photoreceptor-specific markers (RCVRN). Adeno-associated virus (AAV)-mediated gene augmentation with RS1 at the photoreceptor immature stage rescued the rod photoreceptor developmental delay in ROs with the RS1 (E72K) mutation. CONCLUSIONS: The RS1 (E72K) mutation results in the photoreceptor development delay in ROs and can be partially rescued by the RS1 gene augmentation therapy.

Generation of a gene-corrected isogenic iPSC cell line from an X-linked retinoschisis patient with a hemizygous mutation c.304C > T (p.R102W) in RS1 gene.

X-linked retinoschisis (XLRS) is one of the most common retinal genetic diseases with progressive visual impairment in childhood affecting males. It is manifested with macular and/or peripheral schisis in neural retinas with no effective treatment. Previously, we successfully generated a human-induced pluripotent stem cell (iPSC) line from an XLRS patient carrying the hemizygous RS1 c. 304C > T (p.R102W) mutation. Here, we corrected the c.304C > T mutation in the RS1 gene using CRISPR/Cas9 technology to generate an isogenic control. This cell line is valuable for the study of XLRS.

One-stop assembly of adherent 3D retinal organoids from hiPSCs based on 3D-printed derived PDMS microwell platform.

The three-dimensional (3D) retinal organoids (ROs) derived from human induced pluripotent stem cells (hiPSCs), mimicking the growth and development of the human retina, is a promising model for investigating inherited retinal diseasesin vitro. However, the efficient generation of homogenous ROs remains a challenge. Here we introduce a novel polydimethylsiloxane (PDMS) microwell platform containing 62 V-bottom micro-cavities for the ROs differentiation from hiPSCs. The uniform adherent 3D ROs could spontaneously form using neural retina (NR) induction. Our results showed that the complex of NR (expressing VSX2), ciliary margin (CM) (expressing RDH10), and retinal pigment epithelium (RPE) (expressing ZO-1, MITF, and RPE65) developed in the PDMS microwell after the differentiation. It is important to note that ROs in PDMS microwell platforms not only enable one-stop assembly but also maintain homogeneity and mature differentiation over a period of more than 25 weeks without the use of BMP4 and Matrigel. Retinal ganglion cells (expressing BRN3a), amacrine cells (expressing AP2a), horizontal cells (expressing PROX1 and AP2α), photoreceptor cells for cone (expressing S-opsin and L/M-opsin) and rod (expressing Rod opsin), bipolar cells (expressing VSX2 and PKCα), and Müller glial cells (expressing GS and Sox9) gradually emerged. Furthermore, we replaced fetal bovine serum with human platelet lysate and established a xeno-free culture workflow that facilitates clinical application. Thus, our PDMS microwell platform for one-stop assembly and long-term culture of ROs using a xeno-free workflow is favorable for retinal disease modeling, drug screening, and manufacturing ROs for clinical translation.

Generation of a gene-corrected human iPSC line (CSUASOi004-A-1) from a retinitis pigmentosa patient with heterozygous c.2699 G>A mutation in the PRPF6 gene.

Retinitis pigmentosa (RP) is one of the most common inherited retinal diseases characterized by nyctalopia, progressive vision loss and visual field contraction. we previously generated an induced pluripotent stem cell line (CSUASOi004-A) from a RP patient with heterozygous PRPF6 c.2699 G>A (p.R900H) mutation. Here we corrected the PRPF6 c.2699 G>A mutation genetically using CRISPR/Cas9 technology to generate an isogenic control (CSUASOi004-A-1), which can provide a valuable resource in the research of the disease.

Aberrant Retinal Pigment Epithelial Cells Derived from Induced Pluripotent Stem Cells of a Retinitis Pigmentosa Patient with the PRPF6 Mutation.

Pre-mRNA processing factors (PRPFs) are vital components of the spliceosome and are involved in the physiological process necessary for pre-mRNA splicing to mature mRNA. As an important member, PRPF6 mutation resulting in autosomal dominant retinitis pigmentosa (adRP) is not common. Recently, we reported the establishment of an induced pluripotent stem cells (iPSCs; CSUASOi004-A) model by reprogramming the peripheral blood mononuclear cells of a PRPF6-related adRP patient, which could recapitulate a consistent disease-specific genotype. In this study, a disease model of retinal pigment epithelial (RPE) cells was generated from the iPSCs of this patient to further investigate the underlying molecular and pathological mechanisms. The results showed the irregular morphology, disorganized apical microvilli and reduced expressions of RPE-specific genes in the patient's iPSC-derived RPE cells. In addition, RPE cells carrying the PRPF6 mutation displayed a decrease in the phagocytosis of fluorescein isothiocyanate-labeled photoreceptor outer segments and exhibited impaired cell polarity and barrier function. This study will benefit the understanding of PRPF6-related RPE cells and future cell therapy.

Establishment of non-integrate induced pluripotent stem cell line CSUASOi006-A, from urine-derived cells of a PRPF8-related dominant retinitis pigmentosa patient.

Retinitis pigmentosa (RP) is a group of inherited retinal disorders characterized by the progressive photoreceptors and pigment epithelial cells dysfunction. Here, we report the human induced pluripotent stem cell line (iPSC) CSUASOi006-A, generated from urine-derived cells (UCs) of a 17-year-old male patient with clinically diagnosed RP carrying point mutation (c.C5792T) in the pre-mRNA processing factor 8 gene (PRPF8). The newly derived CSUASOi006-A cell line has the patient's same mutation (c.C5792T) and could provide useful resources for studying the pathogenic mechanism of PRPF8-related RP.

Establishment of induced pluripotent stem cell line CSUASOi004-A by reprogramming peripheral blood mononuclear cells of a PRPF6-related dominant retinitis pigmentosa patient.

We have established the patient-specific induced pluripotent stem (iPS) cell line CSUASOi004-A by using peripheral blood mononuclear cells (PBMCs) of a retinitis pigmentosa (RP) patient with a PRPF6 gene mutation (c.G2699A:p.R900H). CSUASOi004-A was established by a non-integrative method with four episomal plasmids containing the Yamanaka factors. The cell line with the specific point mutation had the typical features of normal iPS cells. For instance, the cells expressed pluripotency markers, generated all three germ layers and had a normal karyotype, and they can serve as a model for unravelling the pathogenic mechanisms underlying PRPF6-associated retinal degeneration.

Establishment of induced pluripotent stem cell line CSUASOi003- A from an autosomal recessive retinitis pigmentosa patient carrying compound heterozygous mutations in CRB1 gene.

Crumbs homologue 1 (CRB1) mutations have been found in retinitis pigmentosa (RP) patients lead to severe retinal dystrophies. The human induced pluripotent stem (iPS) cell line CSUASOi003-A derived from peripheral blood mononuclear cells (PBMCs) of a patient carrying two heterozygous mutations (2249G>A p.G750D and c.2809G>A p.A937T) in CRB1 gene was generated by non-integrative reprogramming technology. Pluripotency and differentiation capacity were assessed by immunocytochemistry and quantitative polymerase chain reaction (qPCR). The RP patient-specific iPS cell line provide a powerful model for evaluating the pathological phenotypes of the disease.

Transcriptomic Analysis of the Developmental Similarities and Differences Between the Native Retina and Retinal Organoids.

Purpose: We performed a bioinformatic transcriptome analysis to determine the alteration of gene expression between the native retina and retinal organoids in both mice and humans. Methods: The datasets of mouse native retina (GSE101986), mouse retinal organoids (GSE102794), human native retina (GSE104827), and human retinal organoids (GSE119320) were obtained from Gene Expression Omnibus. After normalization, a principal component analysis was performed to categorize the samples. The genes were clustered to classify them. A functional analysis was performed using the bioinformatics tool Gene ontology enrichment to analyze the biological processes of selected genes and cellular components. Results: The development of retinal organoids is slower than that in the native retina. In the early stage, cell proliferation predominates. Subsequently, neural differentiation is dominant. In the later stage, the dominant differentiated cells are photoreceptors. Additionally, the fatty acid metabolic process and mitochondria-related genes are upregulated over time, and the glycogen catabolic process and activin receptors are gradually downregulated in human retinal organoids. However, these trends are opposite in mouse retinal organoids. There are two peaks in mitochondria-related genes, one in the early development period and another during the photoreceptor development period. It takes about five times longer for human retinal development to achieve similar levels of mouse retinal development. Conclusions: Our study reveals the similarities and differences in the developmental features of retinal organoids as well as the corresponding relationship between mouse and human retinal development.

Establishment of a human induced pluripotent stem cell line (CSUASOi005-A), from peripheral blood mononuclear cells of a patient with X-linked juvenile retinoschisis carrying a novel mutation in RS1 gene.

X-linked retinoschisis (XLRS) is a one of most common retinal genetic diseases of juvenile progressive vitreoretinal degeneration in males, which caused by the mutation of RS1 gene. In this study, an induced pluripotent stem cell (iPSC) line was generated from human peripheral blood mononuclear cells (PBMC) of a 13-year-old male patient with X-linked juvenile retinoschisis carrying a novel mutation in RS1 gene. The iPSCs exhibited iPSC morphology, expression of the pluripotency markers and in vitro differentiation potential, and the CSUASOi005-A iPSC line retained the original mutation (c.527T > A) of RS1 with a normal karyotype.

Establishment of a non-integrate iPS cell line CSUASOi002-A, from urine-derived cells of a female patient with macular corneal dystrophy carrying compound heterozygous CHST6 mutations.

We report the human induced pluripotent stem cell line (iPSC) CSUASOi002-A, generated from urine-derived cells (UCs) from a 51-year-old female patient carrying compound heterozygous mutations (c.62_63delTinsGA and c.C892T) in the carbohydrate sulfotransferase 6 gene (CHST6). This patient was from a Chinese family of three siblings with macular corneal dystrophy (MCD). Patient UCs were reprogrammed by electroporation using the episomal plasmids (OCT4, SOX2, KLF4, l-MYC, LIN28 and shP53). The human MCD-UiPS cell line CSUASOi002-A retained the disease-associated genotype, while expressed pluripotent stem cell markers and could be differentiated into cells of all three germ layers.

Establishment of CSUASOi001-A, a non-integrated induced pluripotent stem cell line from urine-derived cells of a Chinese patient carrying RS1 gene mutation.

X-linked juvenile retinoschisis (XLRS) is one of the most severely affected genetic causes of irreversible retinal degeneration diseases in young males, especially school-age boys. Here, we generated induced pluripotent stem cells (iPSCs) from a Chinese 11-year-old male with clinically diagnosed XLRS. Urine sample was collected with appropriate cooperation, then isolated cells were expanded for subsequent reprogramming procedure using integration-free Sendai virus. The newly derived CSUASOi001-A iPS cell line harboring the c.304C > T mutation in the RS1 gene (p.R102W) provides a useful resource to investigate pathogenic mechanisms in XLRS.