RESUMEN
Type 2 idiopathic macular telangiectasia (MacTel-2) is a progressive adult-onset macular disease associated with bilateral perifoveal vascular changes, Muller cell degeneration and increased blood-retinal barrier permeability. The pathophysiological mechanisms of MacTel-2 remain unclear, however it was previously reported that anti-retinal antibodies in MacTel-2 patients are a significant feature of the disease. In this study, we aimed to compare the prevalence of anti-retinal antibodies in patients MacTel-2, healthy controls and patients with other retinal diseases. MacTel-2 patients diagnosed with multimodal imaging were enrolled and their disease severities were graded using spectral-domain optical coherence tomography. For comparison, patients with age-related macular degeneration (AMD), inherited retinal diseases (IRDs) or no retinal disease (healthy controls) were recruited as controls. Blood serum samples were screened for immunoglobulin G anti-retinal antibodies by western blotting, followed by densitometry analysis. Odds ratios (OR) with 95% confidence intervals (CI) were calculated and p < 0.05 considered statistically significant. Overall, anti-retinal antibody-positive cases were older (64 ± 15 vs 53 ± 17 years, p < 0.001) and females were more likely to develop anti-retinal antibodies (OR: 2.41, CI: 1.12-5.18). The frequency of anti-retinal antibody detection in MacTel-2 patients (n = 42, 36%) was not significantly different from healthy controls (n = 52, 25%) or IRD patients (n = 18, 25%) and the majority of MacTel-2 patients had no anti-retinal antibodies. In contrast, the frequency of anti-retinal antibody detection was significantly higher in patients with AMD (n = 15, 73%, p < 0.001). The lack of a greater anti-retinal antibody frequency or specificity in the MacTel-2 cohort suggests that antibody mediated immunological mechanisms may play a less significant role in MacTel-2 disease pathogenesis.
Asunto(s)
Retinopatía Diabética , Degeneración Macular , Telangiectasia Retiniana , Adulto , Retinopatía Diabética/patología , Femenino , Humanos , Inmunoglobulina G , Degeneración Macular/patología , Retina/patología , Telangiectasia Retiniana/diagnóstico , Telangiectasia Retiniana/patología , Tomografía de Coherencia Óptica/métodosRESUMEN
The ATP-binding cassette subfamily A member 4 gene (ABCA4)-associated retinopathy, Stargardt disease, is the most common monogenic inherited retinal disease. Given the pathogenicity of numerous ABCA4 variants is yet to be examined and a significant proportion (more than 15%) of ABCA4 variants are categorized as splice variants in silico, we therefore established a fibroblast-based splice assay to analyze ABCA4 variants in an Australian Stargardt disease cohort and characterize the pathogenic mechanisms of ABCA4 variants. A cohort of 67 patients clinically diagnosed with Stargardt disease was recruited. Genomic DNA was analysed using a commercial panel for ABCA4 variant detection and the consequences of ABCA4 variants were predicted in silico. Dermal fibroblasts were propagated from skin biopsies, total RNA was extracted and the ABCA4 transcript was amplified by RT-PCR. Our analysis identified a total of 67 unique alleles carrying 74 unique variants. The most prevalent splice-affecting complex allele c.[5461-10T>C; 5603A>T] was carried by 10% of patients in a compound heterozygous state. ABCA4 transcripts from exon 13 to exon 50 were readily detected in fibroblasts. In this region, aberrant splicing was evident in 10 out of 57 variant transcripts (18%), carried by 19 patients (28%). Patient-derived fibroblasts provide a feasible platform for identification of ABCA4 splice variants located within exons 13-50. Experimental evidence of aberrant splicing contributes to the pathogenic classification for ABCA4 variants. Moreover, identification of variants that affect splicing processes provides opportunities for intervention, in particular antisense oligonucleotide-mediated splice correction.
Asunto(s)
Transportadoras de Casetes de Unión a ATP , Enfermedades de la Retina , Humanos , Enfermedad de Stargardt/genética , Intrones/genética , Transportadoras de Casetes de Unión a ATP/genética , Australia , Exones/genética , Mutación , Enfermedades de la Retina/genética , Fibroblastos , LinajeRESUMEN
Biallelic mutations in the RCBTB1 gene cause retinal dystrophy. Here, we characterized the effects of RCBTB1 gene deficiency in retinal pigment epithelial (RPE) cells derived from a patient with RCBTB1-associated retinopathy and restored RCBTB1 expression in these cells using adeno-associated viral (AAV) vectors. Induced pluripotent stem cells derived from a patient with compound heterozygous RCBTB1 mutations (c.170delG and c.707delA) and healthy control subjects were differentiated into RPE cells. RPE cells were treated with AAV vectors carrying a RCBTB1 transgene. Patient-derived RPE cells showed reduced expression of RCBTB1. Expression of NFE2L2 showed a non-significant reduction in patient RPE cells compared with controls, while expression of its target genes (RXRA, IDH1 and SLC25A25) was significantly reduced. Trans-epithelial electrical resistance, surface microvillus densities and primary cilium lengths were reduced in patient-derived RPE cells, compared with controls. Treatment of patient RPE with AAV vectors significantly increased RCBTB1, NFE2L2 and RXRA expression and cilium lengths. Our study provides the first report examining the phenotype of RPE cells derived from a patient with RCBTB1-associated retinopathy. Furthermore, treatment of patient-derived RPE with AAV-RCBTB1 vectors corrected deficits in gene expression and RPE ultrastructure, supporting the use of gene replacement therapy for treating this inherited retinal disease.
Asunto(s)
Cilios/metabolismo , Expresión Génica , Terapia Genética , Factores de Intercambio de Guanina Nucleótido/genética , Epitelio Pigmentado de la Retina/metabolismo , Transgenes , Diferenciación Celular , Células Cultivadas , Cilios/ultraestructura , Dependovirus/genética , Terapia Genética/métodos , Vectores Genéticos/genética , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Distrofias Retinianas/genética , Distrofias Retinianas/terapia , Epitelio Pigmentado de la Retina/ultraestructura , Transducción GenéticaRESUMEN
PURPOSE: Mutation of the CLN3 gene, associated with juvenile neuronal ceroid lipofuscinosis, has recently been associated with late-onset, non-syndromic retinal dystrophy. Herein we describe the multimodal imaging, immunological and systemic features of an adult with compound heterozygous CLN3 mutations. METHODS: A 50-year-old female with non-syndromic retinal dystrophy from the age of 36 years underwent multimodal retinal imaging, electroretinography, neuroimaging, immunological studies and genetic testing. CLN3 transcripts were amplified from patient leukocytes by reverse transcriptase polymerase chain reaction and characterized by Sanger sequencing. RESULTS: Visual acuity declined to 6/12 and 6/76 due to asymmetrical central scotoma. ERG responses became electronegative and patient's serum contained anti-retinal antibodies. Final visual acuity stabilized at 6/60 bilaterally 3 years after peri-ocular steroid and rituximab infusion. Genetic testing revealed compound heterozygous CLN3 mutations: the 1.02 kb deletion and a novel missense mutation (c.175G>A). In silico, analyses predicted the c.175G>A mutation disrupted an exonic splice enhancer site in exon 3. In patient leukocytes, CLN3 expression was reduced and novel CLN3 transcripts lacking exon 3 were detected. CONCLUSIONS: Our case study shows that (1) non-syndromic CLN3 disease leads to rod and delayed primary cone degeneration resulting in constricting peripheral field and enlarging central scotoma and, (2) the c.175G>A CLN3 mutation, altered splicing of the CLN3 gene. Overall, we provide comprehensive clinical characterization of a patient with non-syndromic CLN3 disease.
Asunto(s)
Glicoproteínas de Membrana/genética , Chaperonas Moleculares/genética , Mutación Missense , Lipofuscinosis Ceroideas Neuronales/genética , Distrofias Retinianas/genética , Autoanticuerpos/sangre , Autoantígenos/inmunología , Western Blotting , Electrorretinografía , Exones , Femenino , Humanos , Persona de Mediana Edad , Imagen Multimodal , Lipofuscinosis Ceroideas Neuronales/diagnóstico , Lipofuscinosis Ceroideas Neuronales/inmunología , Lipofuscinosis Ceroideas Neuronales/fisiopatología , Linaje , Retina/inmunología , Retina/fisiopatología , Distrofias Retinianas/diagnóstico , Distrofias Retinianas/inmunología , Distrofias Retinianas/fisiopatología , Estudios Retrospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Agudeza Visual/fisiologíaRESUMEN
PURPOSE: Paraneoplastic retinopathy can be the first manifestation of systemic malignancy. A subset of paraneoplastic retinopathy is characterized by negative-type electroretinography (ERG) without fundus abnormality. Here we describe the multimodal imaging and clinico-pathological correlation of a unique case of acute progressive paravascular placoid neuroretinopathy with suspected retinal depolarizing bipolar cell dysfunction preceding the diagnosis of metastatic small cell carcinoma of the prostate. METHODS: ERG was performed according to the International Society for Clinical Electrophysiology of Vision standards. Imaging modalities included near-infrared reflectance, blue-light autofluorescence, fluorescein and indocyanine green angiographies, spectral domain optical coherence tomography, ultra-widefield colour and green-light autofluorescence imaging, microperimetry and adaptive optics imaging. Patient serum was screened for anti-retinal antibodies using western blotting. Immunostaining and histological analyses were performed on sections from human retinal tissues and a patient prostate biopsy. RESULTS: Serial multimodal retinal imaging, microperimetry and adaptive optics photography demonstrated a paravascular distribution of placoid lesions characterized by hyper-reflectivity within the outer nuclear layer resembling type 2 acute macular neuroretinopathy. There was no visible lesion within the inner nuclear layer despite electronegative-type ERG. Six months later, the patient presented with metastatic small cell carcinoma of the prostate. Tumour cells were immunopositive for glyceraldehyde-3-phosphate dehydrogenase, enolase and recoverin as well as neuroendocrine markers. The patient's serum reacted to cytoplasmic and nuclear antigens in the prostate biopsy and in human retina. Anti-retinal antibodies against several antigens were detected by both commercial and in-house western blots. CONCLUSIONS: A spectrum of autoreactive anti-retinal antibodies is associated with a unique phenotype of acute progressive paravascular placoid neuroretinopathy resulting in degeneration of photoreceptor cells, inner retinal dysfunction and classic electronegative ERG in paraneoplastic retinopathy. Detailed clinical, functional and immunological phenotyping of paraneoplastic retinopathy illustrated the complex mechanism of paraneoplastic syndrome.
Asunto(s)
Electrorretinografía , Síndromes Paraneoplásicos/diagnóstico , Retina/patología , Enfermedades de la Retina/diagnóstico , Enfermedad Aguda , Humanos , Masculino , Persona de Mediana Edad , Imagen MultimodalRESUMEN
BACKGROUND: The culture of retinal progenitors from an accessible adult stem cell source such as the limbus could provide a useful autologous source of retinal cell therapies. The human corneoscleral limbus contains multipotent stem cells that can be cultured as floating neurospheres. Previous work in rodents has demonstrated neuronal and photoreceptor differentiation from limbal neurosphere cultures. Here, this study has examined undifferentiated cultured adult human limbal neurospheres as donor cells for retinal cell therapies by transplantation into a rat model of retinal degeneration. METHODS: Gene expression in limbal neurospheres was examined by immunostaining and western blot. Human limbal neurospheres were transplanted into the subretinal space of Royal College of Surgeon's rats. Rats were monitored by optical coherence tomography for 6 weeks then processed for retinal histology. RESULTS: Human limbal neurospheres expressed the neural lineage markers, Nestin, sex determining region box-2 and N-cadherin, and the retinal transcription factors microphthalmia-associated transcription factor, sex determining region box-2 and orthodentical homeobox-2. Human limbal neurospheres could be cultured to express NeuN, neurofilament and rhodopsin. Rats receiving saline or no injection underwent complete degeneration of the retinal outer nuclear layer after 3 weeks. In contrast, rats injected with human limbal neurospheres or retinal pigment epithelial cells maintained the outer nuclear layer for up to 6 weeks. Gene expression in transplanted limbal neurospheres was inconsistent with the production of mature retinal pigment epithelial or photoreceptor cells. CONCLUSIONS: Human limbal neurospheres represent an accessible source of autologous donor cells for the treatment of retinal diseases.
Asunto(s)
Muerte Celular , Limbo de la Córnea/citología , Epitelio Pigmentado Ocular/patología , Células Fotorreceptoras Retinianas Conos/patología , Degeneración Retiniana/patología , Trasplante de Células Madre , Células Madre/citología , Animales , Antígenos Nucleares/biosíntesis , Antígenos Nucleares/genética , Western Blotting , Diferenciación Celular , Células Cultivadas , ADN/genética , Modelos Animales de Enfermedad , Regulación de la Expresión Génica , Genes Homeobox/genética , Humanos , Inyecciones Intraoculares , Limbo de la Córnea/metabolismo , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Epitelio Pigmentado Ocular/metabolismo , Ratas , Células Fotorreceptoras Retinianas Conos/metabolismo , Degeneración Retiniana/genética , Degeneración Retiniana/cirugía , Rodopsina/biosíntesis , Rodopsina/genética , Células Madre/metabolismo , Tomografía de Coherencia ÓpticaRESUMEN
The human induced pluripotent stem cell (iPSC) line LEIi019-A was generated from a patient with early-onset pattern dystrophy caused by a heterozygous mutation NM_001270525.1:c.259G>A (p.Glu87Lys) in OTX2. Patient-derived dermal fibroblasts were reprogrammed using episomal plasmids containing reprogramming factors OCT4, SOX2, KLF4, MYCL, LIN28, TP53 shRNA and miR-302/367. The iPSC line expressed pluripotency markers, displayed a normal 46,XY karyotype and demonstrated the ability to differentiate into the three primary germ layers, retinal organoids and retinal pigment epithelial cells.
Asunto(s)
Células Madre Pluripotentes Inducidas , Factor 4 Similar a Kruppel , Factores de Transcripción Otx , Distrofias Retinianas , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Factores de Transcripción Otx/genética , Factores de Transcripción Otx/metabolismo , Distrofias Retinianas/genética , Distrofias Retinianas/patología , Línea Celular , Diferenciación Celular , Masculino , MutaciónRESUMEN
Inherited retinal diseases (IRDs) are a heterogeneous group of blinding genetic disorders caused by pathogenic variants in genes expressed in the retina. In this study, we sought to develop a method for rapid evaluation of IRD gene variant pathogenicity by inducing expression of retinal genes in patient-derived fibroblasts using CRISPR-activation (CRISPRa). We demonstrate CRISPRa of CRB1 expression in fibroblasts derived from patients with retinitis pigmentosa, enabling investigation of pathogenic mechanisms associated with specific variants. We show the CRB1 c.4005 + 1G>A variant caused exon 11 skipping in CRISPR-activated fibroblasts and retinal organoids (ROs) derived from the same RP12 patient. The c.652 + 5G>C variant was shown to enhance exon 2 skipping in CRISPR-activated fibroblasts and differentially affected CRB1 isoform expression in fibroblasts and ROs. Our study demonstrates an accessible platform for transcript screening of IRD gene variants in patient-derived fibroblasts, which can potentially be applied for rapid pathogenicity assessments of any gene variant.
Asunto(s)
Sistemas CRISPR-Cas , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Humanos , Especies Reactivas de Oxígeno/metabolismo , Virulencia , Edición Génica , Expresión Génica , Proteínas del Ojo/genética , Proteínas del Ojo/metabolismo , Proteínas de la Membrana/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismoRESUMEN
Usher syndrome (USH) is the most common cause of inherited deaf-blindness. Here, we produced the LEIi020-A and LEIi020-B induced pluripotent stem cell (iPSC) lines from dermal fibroblasts derived from a patient with USH1B caused by inheritance of homozygous c.496del variants in MYO7A using episomal plasmids encoding OCT4, SOX2, KLF4, L-MYC, LIN28, mir302/367 microRNA and shRNA for TP53. Both iPSC lines expressed pluripotency markers, demonstrated trilineage differentiation potential and displayed a 46,XY karyotype. These cell lines represent a valuable resource for the production of retinal and otic tissues to support research into the pathogenesis and treatment of USH1B.
Asunto(s)
Homocigoto , Células Madre Pluripotentes Inducidas , Factor 4 Similar a Kruppel , Miosina VIIa , Síndromes de Usher , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Síndromes de Usher/genética , Síndromes de Usher/patología , Línea Celular , Diferenciación Celular , Masculino , Fibroblastos/metabolismoRESUMEN
Mutations in the RCBTB1 gene cause inherited retinal disease; however, the pathogenic mechanisms associated with RCBTB1 deficiency remain poorly understood. Here, we investigated the effect of RCBTB1 deficiency on mitochondria and oxidative stress responses in induced pluripotent stem cell (iPSC)-derived retinal pigment epithelial (RPE) cells from control subjects and a patient with RCBTB1-associated retinopathy. Oxidative stress was induced with tert-butyl hydroperoxide (tBHP). RPE cells were characterized by immunostaining, transmission electron microscopy (TEM), CellROX assay, MitoTracker assay, quantitative PCR and immunoprecipitation assay. Patient-derived RPE cells displayed abnormal mitochondrial ultrastructure and reduced MitoTracker fluorescence compared with controls. Patient RPE cells displayed increased levels of reactive oxygen species (ROS) and were more sensitive to tBHP-induced ROS generation than control RPE. Control RPE upregulated RCBTB1 and NFE2L2 expression in response to tBHP treatment; however, this response was highly attenuated in patient RPE. RCBTB1 was co-immunoprecipitated from control RPE protein lysates by antibodies for either UBE2E3 or CUL3. Together, these results demonstrate that RCBTB1 deficiency in patient-derived RPE cells is associated with mitochondrial damage, increased oxidative stress and an attenuated oxidative stress response.
Asunto(s)
Antioxidantes , Enfermedades de la Retina , Humanos , Especies Reactivas de Oxígeno/metabolismo , Antioxidantes/metabolismo , Enfermedades de la Retina/metabolismo , Células Epiteliales/metabolismo , Mitocondrias/metabolismo , Pigmentos Retinianos/metabolismo , Factores de Intercambio de Guanina Nucleótido/metabolismoRESUMEN
Two human iPSC lines were generated from dermal fibroblasts derived from a patient with retinitis pigmentosa caused by CRB1 mutation using episomal plasmids containing OCT4, SOX2, LIN28, KLF4, L-MYC and mp53DD. These clonal iPSC lines carry compound heterozygous mutations in CRB1 (c.2555 T > C and c.3014A > T). Both lines expressed pluripotency markers, displayed a normal karyotype and demonstrated the ability to differentiate into the three primary germ layers, as well as retinal organoids.
Asunto(s)
Células Madre Pluripotentes Inducidas , Retinitis Pigmentosa , Diferenciación Celular , Línea Celular , Proteínas del Ojo/genética , Fibroblastos , Humanos , Factor 4 Similar a Kruppel , Proteínas de la Membrana , Mutación , Proteínas del Tejido Nervioso , Retinitis Pigmentosa/genéticaRESUMEN
Stargardt disease (STGD1) is the most common inherited retinal dystrophy and ABCA4 c.546--10 T>C is the most commonly reported splice mutation. Here, we generated and characterized two induced pluripotent stem cell (iPSC) lines from a STGD1 patient with compound heterozygous mutations in ABCA4 (c.[5461-10 T > C;5603A > T];[4163 T > C;455G > A]). Episomal vectors containing OCT4, SOX2, KLF4, L-MYC, LIN28 and mp53DD were employed to conduct the reprogramming of patient-derived fibroblasts. Both lines had a normal karyotype, displayed iPSC morphology, expressed pluripotency markers and showed trilineage differentiation potential. These lines can provide a powerful platform for further investigating the pathophysiological consequences of mutations in ABCA4.
Asunto(s)
Células Madre Pluripotentes Inducidas , Transportadoras de Casetes de Unión a ATP/genética , Diferenciación Celular , Línea Celular , Humanos , Factor 4 Similar a Kruppel , Mutación , Enfermedad de StargardtRESUMEN
Mutations in ABCA4 gene are causative for autosomal recessive Stargardt disease (STGD1), the most common inherited retinal dystrophy. Here, we report the generation of an induced pluripotent stem cell (iPSC) line from a STGD1 patient carrying biallelic c.[5461-10T>C;5603A>T];[6077T>C] mutations in the ABCA4 gene. Episomes carrying OCT4, SOX2, KLF4, L-MYC, LIN28 and mp53DD were employed for the reprogramming of patient-derived fibroblasts. This iPSC line expressed comparable pluripotency markers as in a commercially available human iPSC line, displayed normal karyotype and potential for trilineage differentiation, and were negative for both reprogramming episomes and mycoplasma test.
Asunto(s)
Células Madre Pluripotentes Inducidas , Transportadoras de Casetes de Unión a ATP/genética , Diferenciación Celular , Humanos , Factor 4 Similar a Kruppel , Mutación , Enfermedad de StargardtRESUMEN
BACKGROUND: Mutations in CLN3 cause Batten disease, however non-syndromic CLN3 disease, characterized by retinal-specific degeneration, has been also described. Here, we characterized an induced pluripotent stem cell (iPSC)-derived disease model derived from a patient with non-syndromic CLN3-associated retinopathy. METHODS: Patient-iPSC, carrying the 1 kb-deletion and c.175G>A variants in CLN3, coisogenic iPSC, in which the c.175G>A variant was corrected, and control iPSC were differentiated into neural retinal organoids (NRO) and cardiomyocytes. CLN3 transcripts were analyzed by Sanger sequencing. Gene expression was characterized by qPCR and western blotting. NRO were characterized by immunostaining and electron microscopy. RESULTS: Novel CLN3 transcripts were detected in adult human retina and control-NRO. The major transcript detected in patient-NRO displayed skipping of exons 2 and 4-9. Accumulation of subunit-C of mitochondrial ATPase (SCMAS) protein was demonstrated in patient-derived cells. Photoreceptor progenitor cells in patient-NRO displayed accumulation of peroxisomes and vacuolization of inner segments. Correction of the c.175G>A variant restored CLN3 mRNA and protein expression and prevented SCMAS and inner segment vacuolization. CONCLUSION: Our results demonstrate the expression of novel CLN3 transcripts in human retinal tissues. The c.175G>A variant alters splicing of the CLN3 pre-mRNA, leading to features consistent with CLN3 deficiency, which were prevented by gene correction.
Asunto(s)
Células Madre Pluripotentes Inducidas/metabolismo , Glicoproteínas de Membrana/genética , Chaperonas Moleculares/genética , Lipofuscinosis Ceroideas Neuronales/genética , Organoides/metabolismo , Retina/metabolismo , Diferenciación Celular , Células Cultivadas , Femenino , Humanos , Células Madre Pluripotentes Inducidas/citología , Glicoproteínas de Membrana/metabolismo , Chaperonas Moleculares/metabolismo , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Lipofuscinosis Ceroideas Neuronales/patología , Organoides/patología , Peroxisomas/metabolismo , Mutación Puntual , Empalme del ARN , Retina/patologíaRESUMEN
The human induced pluripotent stem cell (iPSC) lines LEIi015-A and LEIi015-B were derived from a patient with inherited retinal disease caused by compound heterozygous mutations in the SNRNP200 gene (c.[1792C>T];[3341T>C]). Dermal fibroblasts were transfected with episomal plasmids carrying transgenes encoding OCT4, SOX2, KLF4, L-MYC, LIN28, mir302/367 microRNA and shRNA for P53. The clonal iPSC lines LEIi015-A and LEIi015-B expressed iPSC markers, were free from genomic alterations and demonstrated trilineage differentiation potential.
Asunto(s)
Células Madre Pluripotentes Inducidas , Enfermedades de la Retina , Diferenciación Celular , Línea Celular , Fibroblastos , Humanos , Factor 4 Similar a Kruppel , Mutación , Ribonucleoproteínas Nucleares PequeñasRESUMEN
Background: Mutations in the RCC1 and BTB domain-containing protein 1 (RCBTB1) gene have been implicated in a rare form of retinal dystrophy. Herein, we report the clinical features of a 45-year-old Singaporean-Chinese female and her presymptomatic sibling, who each possesses compound heterozygous mutations in RCBTB1. Expression of RCBTB1 in patient-derived cells was evaluated.Materials and Methods: The natural history was documented by a series of ophthalmic examinations including electroretinography, fundus autofluorescence imaging, spectral-domain optical coherence tomography, visual field, microperimetry, and adaptive optics retinal imaging. Patient DNA was genetically analysed using a 537-gene Next Generation Sequencing panel and targeted Sanger sequencing. Expression of RCBTB1 in lymphocytes, fibroblasts, and induced pluripotent stem cells (iPSC) derived from the proband and healthy controls was characterized by quantitative PCR, Sanger sequencing, and western blotting.Results: The proband presented with left visual distortion at age 40 due to extrafoveal chorioretinal atrophy. Atrophy expanded at 1.3 (OD) and 1.0 (OS) mm2/year. Total macular volume declined by 0.09 (OD) and 0.13 (OS) mm3/year. Microperimetry demonstrated enlarging scotoma in both eyes. Generalised cone dysfunction was demonstrated by electroretinography. A retinal dystrophy panel testing revealed biallelic frameshifting mutations, c.170delG (p.Gly57Glufs*12) and c.707delA (p.Asn236Thrfs*11) in RCBTB1. The level of RCBTB1 mRNA expression was reduced in patient-derived lymphocytes compared to controls. RCBTB1 protein was detected in control fibroblasts and iPSC but was absent in patient-derived cells.Conclusions: Atrophy expansion rate and macular volume change are feasible endpoints for monitoring RCBTB1-associated retinopathy. We provide further functional evidence of pathogenicity for two disease-causing variants using patient-derived iPSCs.
Asunto(s)
Factores de Intercambio de Guanina Nucleótido/genética , Mutación/genética , Distrofias Retinianas/genética , Pueblo Asiatico/etnología , Pueblo Asiatico/genética , Western Blotting , Electrorretinografía , Femenino , Fibroblastos/metabolismo , Angiografía con Fluoresceína , Expresión Génica , Factores de Intercambio de Guanina Nucleótido/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Linfocitos/metabolismo , Persona de Mediana Edad , Fenotipo , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Singapur/epidemiologíaRESUMEN
Retinitis pigmentosa 11 (RP11) is caused by dominant mutations in PRPF31, however a significant proportion of mutation carriers do not develop retinopathy. Here, we investigated the relationship between CNOT3 polymorphism, MSR1 repeat copy number and disease penetrance in RP11 patients and non-penetrant carriers (NPCs). We further characterized PRPF31 and CNOT3 expression in fibroblasts from eight RP11 patients and one NPC from a family carrying the c.1205C>T variant. Retinal organoids (ROs) and retinal pigment epithelium (RPE) were differentiated from induced pluripotent stem cells derived from RP11 patients, an NPC and a control subject. All RP11 patients were homozygous for the 3-copy MSR1 repeat in the PRPF31 promoter, while 3/5 NPCs carried a 4-copy MSR1 repeat. The CNOT3 rs4806718 genotype did not correlate with disease penetrance. PRFP31 expression declined with age in adult cadaveric retina. PRPF31 and CNOT3 expression was reduced in RP11 fibroblasts, RO and RPE compared with controls. Both RP11 and NPC RPE displayed shortened primary cilia compared with controls, however a subpopulation of cells with normal cilia lengths was present in NPC RPE monolayers. Our results indicate that RP11 non-penetrance is associated with the inheritance of a 4-copy MSR1 repeat, but not with CNOT3 polymorphisms.
Asunto(s)
Proteínas del Ojo/genética , Penetrancia , Retinitis Pigmentosa/genética , Adolescente , Adulto , Anciano , Células Cultivadas , Niño , Proteínas del Ojo/metabolismo , Femenino , Genes Modificadores , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo Genético , Retina/metabolismo , Retina/patología , Retinitis Pigmentosa/metabolismo , Retinitis Pigmentosa/patología , Receptores Depuradores de Clase A/genética , Receptores Depuradores de Clase A/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Autosomal recessive Stargardt disease is the most common cause of inherited retinal disease. In this report, we describe the generation and characterization of two human induced pluripotent stem cell (iPSC) lines from a patient with compound heterozygous mutations in the ABCA4 gene (c.[768G>T];[6079C>T]). Patient dermal fibroblasts were reprogrammed using episomal plasmids encoding OCT4, SOX2, KLF4, L-MYC, LIN28, mir302/367 microRNA and shRNA for P53. The clonal iPSC lines LEIi012-A and LEIi012-B were established. Both lines had a normal karyotype, displayed iPSC morphology, expressed pluripotency genes at similar levels to control iPSC and displayed trilineage differentiation potential during embryoid body differentiation.
Asunto(s)
Transportadoras de Casetes de Unión a ATP , Células Madre Pluripotentes Inducidas , Enfermedad de Stargardt , Transportadoras de Casetes de Unión a ATP/genética , Diferenciación Celular , Línea Celular , Humanos , Factor 4 Similar a Kruppel , Mutación , Enfermedad de Stargardt/genéticaRESUMEN
Mutations in the USH2A gene are the most common cause of Usher syndrome and autosomal recessive non-syndromic retinitis pigmentosa. Here, we describe the generation of three induced pluripotent stem cell lines from dermal fibroblasts derived from a patient carrying biallelic c.949C > A and c.1256G > T variants in the USH2A gene, using episomal reprogramming plasmids expressing OCT4, SOX2, KLF4, MYCL, LIN28, mir302/367 and shRNA targeting TP53. All three lines expressed pluripotency markers, displayed unaltered karyotypes as well as trilineage differentiation potential, and were negative for reprogramming episomes and mycoplasma.
RESUMEN
BACKGROUND: Deletion-insertion (delins) variants in the retina-specific ATP-binding cassette transporter gene, subfamily A, member 4 (ABCA4) accounts for <1% in Stargardt disease. The consequences of these delins variants on splicing cannot be predicted with certainty without supporting in vitro data. METHODS: Candidate ABCA4 variants were revealed by genetic and segregation analysis of a family with pseudodominant Stargardt disease using a commercial panel and Sanger sequencing. RNA extracted from patient-derived fibroblasts was analyzed by RT-PCR to evaluate splicing behavior of the ABCA4 variants. RESULTS: Affected members carrying the novel c.6031_6044delinsAGTATTTAACCAATATTT variant in exon 44 presented with contrasting phenotypes; from early-onset cone-rod dystrophy to late-onset macular dystrophy. This variant resulted in a 56-nucleotide deletion in the mutant allele by activation of a cryptic splice acceptor site which disrupts the reading frame and results in a premature termination codon (p.Ile2003LeufsTer41). If translated, the crucial functional domains near the C-terminus would be truncated from the ABCA4 protein. CONCLUSION: This work demonstrates the intrafamilial phenotypic variability in a pseudodominant Stargardt disease pedigree and the use of patient-derived fibroblasts to evaluate the effect of a novel ABCA4 delins variant on splicing to complement in silico pathogenicity assessment.