RARE DISEASE
Leber congenital amaurosis
Leber congenital amaurosis
Leber congenital amaurosis
Synonyms: Amaurosis congenita of Leber
Synonyms: Amaurosis congenita of Leber
Synonyms: Amaurosis congenita of Leber
Drug discovery
22
drugs
With orphan designations
Overview
Leber congenital amaurosis (LCA) is a group of autosomal recessive inherited retinal dystrophies causing severe vision loss or blindness at birth/infancy due to photoreceptor dysfunction. Over 25 genes are implicated, including CEP290 (15%), GUCY2D (12%), CRB1 (10%), and RPE65 (8%). Key features include nystagmus, sluggish pupillary reflexes, and a non-recordable electroretinogram (ERG) [1][2][12]. Diagnosis combines clinical signs, ERG, and genetic testing [6][12].
Therapies
Gene therapy: FDA-approved voretigene neparvovec (RPE65 mutations) [16]; antisense oligonucleotides (e.g., sepofarsen for CEP290 IVS26 variant) [17] and CRISPR-based therapies in trials [4][8].
Supportive care: Low-vision aids, mobility training, and management of ocular complications (e.g., cataracts) [6][15].
Categories: rare genetic diseases, rare neurological diseases, rare ophthalmic disorders
Research Papers
987 drug discovery papers about Leber congenital amaurosis, with 4 first-in-class and 1 next-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
987 drug discovery papers about Leber congenital amaurosis, with 4 first-in-class and 1 next-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-06-25 | Programmed axon degeneration gene variants in human disease.
Programmed axon degeneration (PAD; also known as Wallerian degeneration) is a conserved pathway controlling axon breakdown following injury or metabolic stress. PAD is driven by the depletion of nicotinamide adenine dinucleotide (NAD) through loss of the pro-survival enzyme NMNAT2 and activation of the pro-degenerative NADase SARM1. Recent genetic studies have identified pathogenic variants in PAD pathway enzymes associated with severe neurodegenerative phenotypes. Pathogenic variants in NAMPT, NMNAT1, NMNAT2, and SARM1 have been identified and will be discussed in this review. NAMPT variants cause sensory and motor neuropathy with neurodevelopmental symptoms. NMNAT1 variants are well-characterized causes of Leber Congenital Amaurosis type 9, while NMNAT2 variants result in peripheral neuropathies with childhood onset. SARM1 gain-of-function variants with constitutively active NADase activity are enriched in amyotrophic lateral sclerosis patients. These findings demonstrate that maintaining proper NAD homeostasis is crucial for axon survival, and disruption through genetic variants leads to distinct neurodegenerative outcomes. Understanding these rare variants provides insight into PAD mechanisms and supports development of broad-spectrum neuroprotective therapies targeting this pathway. Current therapeutic approaches include SARM1 inhibitors in clinical trials, gene therapy, and NAD precursor supplementation, offering hope for treating multiple neurodegenerative diseases.
2026-05-25 | Halofantrine protects photoreceptors in multiple models of retinal degeneration.
Inherited retinal degenerative diseases (IRDs), including retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), cause progressive vision impairment due to photoreceptor degeneration. We previously demonstrated the protective effects of reserpine in models of CEP290-LCA and in the female Rhodopsin-P23H rat model of autosomal dominant RP. Given that reserpine is limited by side effects, we expanded our compound screen using retinal organoids from the rd16 mouse model of CEP290-LCA to include structurally diverse small molecules that may converge on proteostasis pathways. Follow-up evaluations in Rhodopsin-P23H rats, human CEP290-LCA retinal organoids, and rd10 mice (a model of PDE6B-RP) identified halofantrine as the most promising molecule, conferring strong protection to both rod and cone photoreceptors and demonstrating therapeutic potential across the divergent IRD models tested. Transcriptome analysis revealed a convergent molecular response to halofantrine across these models, primarily through upregulation of oxidative phosphorylation and ribosomal processes. Notably, halofantrine elicited significant improvements in retinal function, as assessed by electroretinography, despite pharmacokinetically limited and transient retinal exposure after subconjunctival injection in Rhodopsin-P23H rats. Our studies highlight the potential of halofantrine as a gene-independent therapy and suggest that it may be developed for ocular delivery via eye drops for the treatment of IRDs.
2026-04-02 | Oxidative DNA damage drives apoptotic photoreceptor loss in NMNAT1-associated inherited retinal degeneration: a therapeutic opportunity.
Early-onset inherited retinal degenerations (IRDs), such as Leber congenital amaurosis (LCA) caused by pathogenic variants in the NMNAT1 gene, lead to severe vision loss in children. Despite its ubiquitous expression, reduced NMNAT1 function primarily affects photoreceptor cells (PRs) of the retina, yet the mechanisms underlying their vulnerability remain incompletely understood. Here, we demonstrate that reduced NMNAT1 enzyme function due to the p.V9M mutation leads to DNA damage in PRs, characterized by the progressive accumulation of the oxidative DNA adduct 8-oxo-dG in Nmnat1V9M/V9M mutant mice. Cells with oxidative DNA damage also demonstrate DNA double-strand breaks, as evidenced by co-staining with antibodies to phosphorylated H2AX (γH2A.X). This DNA damage correlates with apoptosis-driven PR degeneration, as evidenced by caspase-9 activation and TUNEL staining in the PRs of the Nmnat1V9M/V9M mutant mice, while alternative cell death pathways such as necroptosis and parthanatos were not significantly activated. Treatment with the antioxidant N-acetylcysteine (NAC) reduced oxidative DNA damage and retinal immune responses, mitigated apoptosis, and preserved cone PRs. Longitudinal assessment via optical coherence tomography (OCT) and electroretinography (ERG) revealed sustained structural and functional protection of the retina in NAC-treated mice. These findings establish oxidative DNA damage as a key driver of PR degeneration in the Nmnat1V9M/V9M model and highlight NAC's potential as a therapeutic strategy for NMNAT1-associated IRD and potentially other IRDs in which oxidative DNA damage contributes to disease pathogenesis.
2025-12-04 | Early-Onset Retinopathy in Patients With Variants in SLC6A6 Leading to Impaired Taurine Transport.
Inherited retinal dystrophies are a group of disorders that may lead to progressive vision loss. Improved knowledge of their molecular genetics is important for accurate diagnosis or development of targeted therapies. To identify pathogenic variants in the SLC6A6 gene (encoding TauT, the main transporter for taurine) and assess their role in the molecular pathogenesis of hereditary early-onset retinal dystrophy (EORD) in affected individuals from diverse ethnic backgrounds. This was a retrospective, multicenter observational study conducted between June 2019 and March 2025, involving 7 affected and 10 unaffected individuals from 4 unrelated families recruited in Pakistan, Italy, the US, and France. Pathogenic variants in SLC6A6 in individuals with EORD. Genetic, clinical, and functional outcomes of pathogenic variants in SLC6A6 in individuals with Leber congenital amaurosis (LCA) and EORD. All patients underwent standard clinical examinations, including visual acuity, full-field electroretinography, and multimodal retinal imaging, followed by measurement of fasting plasma taurine levels. In vitro and ex vivo taurine transport and membrane trafficking assays in human embryonic kidney (HEK)-293 cells, as well as patient-derived fibroblasts, were also performed. All 7 affected individuals exhibited LCA/EORD, with extraocular findings in some. Genetic analysis identified homozygous pathogenic SLC6A6 variants in all affected individuals, while unaffected relatives were heterozygous carriers. Families 1 and 2 carried missense variants p.(Thr249Ile) and p.(Ala294Thr), while families 3 and 4 carried truncating variants-a deletion of exon 11 and p.(Thr113Ter), respectively. Functional studies demonstrated that both missense variants are associated with complete loss of taurine transport in HEK-293 cells and patient-derived fibroblasts. Additionally, irrespective of the variants considered, plasma taurine levels in affected individuals were reduced compared with heterozygous carriers (difference between means, -31.7 µmol/L; 95% CI, -42.7 to -20.8; P < .001) and healthy control individuals (difference between means, -37.7 µmol/L; 95% CI -41.6 to -33.8; P < .001). These findings confirm and expand the role of biallelic variants in SLC6A6 in association with LCA/EORD due to impaired taurine transport. These findings suggest that patients with a diagnosis of SLC6A6-related LCA/EORD may be candidates for investigational oral taurine supplementation.
2025-12-01 | Mechanisms and Functions of Chromophore Regeneration in the Classical Visual Cycle: Implications for Retinal Disease Pathogenesis and Therapy
11-cis-retinal, the indispensable chromophore of photoreceptor opsins, is fundamental for light detection and the initiation of visual signal transduction. Its synthesis and regeneration through the visual cycle are critical not only for phototransduction but also for maintaining retinal homeostasis. Disruption of key enzymes, such as retinal pigment epithelium (RPE)65 and retinol dehydrogenases, results in toxic retinoid accumulation, oxidative stress, and progressive photoreceptor degeneration. These pathological mechanisms contribute to inherited and acquired retinal diseases, including Stargardt disease type 1, age-related macular degeneration, Leber congenital amaurosis, retinitis pigmentosa, and fundus albipunctatus. Recent therapeutic advances, ranging from gene replacement therapy with RPE65 (voretigene neparvovec, Luxturna®) to small-molecule modulators and antioxidant strategies, underscore the translational potential of targeting chromophore metabolism. This review outlines molecular processes underlying chromophore synthesis and regeneration, elucidates how disruptions in these processes contribute to inherited and acquired retinal pathologies, and evaluates existing and emerging therapeutic strategies that target chromophore metabolism. We highlight ongoing challenges and critical knowledge gaps to guide future investigations on basic science, translational research, and clinical practice. This review provides a comprehensive overview of the molecular mechanisms, current therapeutic approaches, and outstanding challenges, with a focus on future intervention directions.
gene therapies
2026-09-25 | Clinical translation of CRISPR-Cas9 therapeutics in cancer and inherited genetic disorders.
CRISPR-Cas9, adapted from the bacterial Type II CRISPR adaptive immune system, functions as a programmable RNA-guided endonuclease that employs a single-guide RNA to direct Cas9 to specific genomic loci. CRISPR-Cas9 has transformed targeted genome editing by replacing complex protein engineering with programmable Watson-Crick base pairing between the guide RNA and target DNA. This review was developed following a structured literature search of major biomedical databases and clinical trial registries to synthesize current evidence on the therapeutic applications of CRISPR-Cas9 in oncology and inherited genetic disorders. Clinical studies of ex vivo BCL11A-enhancer editing have shown fetal hemoglobin reactivation, with most evaluable participants with sickle cell disease remaining free of severe vaso-occlusive crises for the prespecified period and most evaluable participants with transfusion-dependent β-thalassemia achieving sustained transfusion independence. In vivo reductions in circulating transthyretin protein levels have been achieved for transthyretin amyloidosis via lipid nanoparticle delivery, while clinically meaningful improvements in selected measures of visual function were observed in a subset of patients receiving subretinal AAV-delivered CRISPR editing for CEP290-associated Leber congenital amaurosis type 10. Preclinical and early clinical studies have further investigated CRISPR-engineered T cells designed to improve antitumor activity, persistence, or resistance to inhibitory signaling. Despite these advances, key translational hurdles include the risk of off-target mutations and large-scale chromosomal rearrangements. Furthermore, immune responses against bacterial Cas9 nucleases and viral delivery vectors may limit the long-term efficacy of CRISPR-based therapies, while technical barriers surrounding delivery to extrahepatic tissues, such as skeletal muscle and the central nervous system, continue to hinder broader clinical success. Ethical concerns regarding germline modifications and the high cost of individualized therapies present additional translational challenges. Consequently, emerging DSB-independent technologies, such as base editing and prime editing, may reduce selected DSB-associated liabilities, but each introduces distinct editing, delivery, and genotoxicity risks that require product-specific evaluation.
2026-08-21 | Gene therapy clinical trials for inherited eye diseases: The pediatric perspective.
Gene therapy is an increasingly useful treatment option, especially in children, where most inherited diseases manifest. This review provides a literature synthesis of current gene therapy treatments in pediatric ophthalmology. Our search encompassed the ClinicalTrials.gov database. Sixteen clinical trials with published results reporting gene therapy for genetic ocular diseases in children (under 18 years) were included. Diseases under investigation for gene therapy in children included Leber's Congenital Amaurosis (CEP290, RPE65 genes), Leber's Hereditary Optic Neuropathy (ND4), Retinitis Pigmentosa (MERTK), Usher Syndrome Type 2 (USH2A), X-linked Retinitis Pigmentosa (RPGR), Achromatopsia (CNGA3, CNGB3), and X-linked Retinoschisis (RS1). Most clinical trials in our search were in Phases 1 or 2, with five studies having progressed to Phase 3. In certain cases, treatment demonstrated encouraging results, providing the patients with an improvement in BCVA, retinal sensitivity, and quality of life. However, the outcome measures regarding the efficacy and tolerability of gene therapy varied and some studies noted adverse events. Clinical trials that have yet to publish their results were also recorded. While the field of pediatric ophthalmology shows promise for gene therapy options, future strategies should include stratified enrollment based on age, separate cohorts for pediatric and adult patients, or adaptive trial designs.
2026-06-23 | Trends in the Engineering of Adeno-Associated Virus (AAV) for Precision Gene Delivery to the Central Nervous System (CNS)
Rare genetic disorders of the central nervous system (CNS) remain some of the most complex and challenging diseases to treat for several reasons. Targeting the CNS, especially the brain, presents one of the greatest obstacles in gene therapy using adeno-associated virus (AAV) vectors. Although various AAVs have been identified for their ability to transduce different cells in the CNS, their effectiveness and efficiency are significantly limited by the presence of neutralising antibodies (NAbs) and restricted cargo capacity. Despite these challenges, our understanding of AAV structure and technological advances continue to enable researchers to develop innovative strategies that have resulted in groundbreaking, FDA-approved therapeutic products now available for Leber congenital amaurosis (LCA) (Luxturna®), spinal muscular atrophy (SMA) (Zolgensma®), and the two recent gene therapy products for aromatic L-amino acid decarboxylase (AADC) deficiency, Kebilidi® and Upstaza®, which currently hold FDA and EMA approval, respectively. This review aims to highlight recent advances in the field of AAV gene therapy for neurological disorders, identify research gaps, and suggest areas for future investigation to enable potential breakthroughs particularly in neurodegenerative, neurodevelopmental, and neuromuscular disorders. We foresee that more tissue- and cell-specific AAV vectors designed using AI-powered platforms will emerge to precisely and efficiently target specific brain regions, transforming how CNS disorders are treated.
2026-06-13 | Therapeutic applications of gene editing using CRISPR-Cas9 in the posterior segment: review of the literature.
CRISPR-Cas gene editing has become increasingly relevant in the treatment of several ophthalmic diseases. Its ability to make precise modifications at the DNA or RNA level has enabled targeted approaches for specific mutations involved in conditions such as Leber congenital amaurosis type 10 (LCA10), certain forms of retinitis pigmentosa, and age-related macular degeneration. This article provides an organized overview of the biological basis of CRISPR-Cas technology and highlights key advances from preclinical studies and early clinical trials. Technical limitations and ongoing safety challenges are also discussed. Programs such as EDIT-101, EDIT-103, and HG202 stand out as important milestones in the evolution of ocular gene editing.
2026-05-20 | Synonymous editing alters ion channel function, favoring prime editing for retinal disease correction.
Point mutations in the KCNJ13 gene cause autosomal recessive childhood blindness, Leber congenital amaurosis (LCA16), by disrupting Kir7.1 channel function. We describe the etiology of the LCA16 retinopathy phenotype in three patients from two unrelated families harboring a homozygous KCNJ13 missense mutation (c.431T>C, p.Leu144Pro). Our in silico prediction and in vitro validation using a human iPSC-derived retinal pigmented epithelium (RPE) model created via lipid nanoparticle-mediated delivery of the adenine base editor (ABE8e) demonstrated that the L144P mutation impairs Kir7.1 channel function and confirmed that non-viral biologic delivery is clinically translatable. We used two cytosine base editors (CBEs, BE4max-WTCas9 and evoCDA-SpCas9-NG) to correct this mutation in an L144P HEK293 stable cell model, achieving high on-target editing efficiency. However, our electrophysiological measurements showed minimal functional rescue of the channel in CBE-edited cells due to bystander nucleotide editing. Editing with evoCDA introduced a bystander missense mutation (L143F), whereas BE4max primarily generated silent mutations. Extended characterization of BE4max-edited cells revealed a distorted mRNA structure, altered half-life, and reduced abundance of cognate tRNA, all associated with these silent changes. In contrast, prime editing successfully restored channel function. Prime editors targeting the L144P locus achieved approximately 20% on-target editing without introducing bystander nucleotide editing or synonymous changes. Functional assessment demonstrated a strong genotype-phenotype correlation, with restored Kir7.1 channel activity observed in 28% of edited cells (12/43). Overall, these results highlight the importance of comprehensive functional validation of genome editing outcomes and emphasize the need for rigorous preclinical studies to translate therapeutic genome editing into first-in-human trials for genetically diverse diseases.
cell therapies
2025-11-01 | Progress of iPSC-derived retinal organoids in the study of inherited retinal diseases.
Inherited retinal diseases (IRDs) constitute a complex and heterogeneous group of rare disorders characterized by significant genetic diversity. These conditions often lead to the degeneration of photoreceptor cells, resulting in severe visual impairment. A major challenge in the study and treatment of IRDs is the lack of appropriate preclinical models for investigating their pathogenesis and evaluating potential therapeutic interventions. In recent years, advances in retinal organoids (ROs) culture technology have provided promising new avenues for IRDs. This review systematically elaborates on the applications of induced pluripotent stem cells (iPSC)-derived ROs as disease models in IRDs such as retinoblastoma (RB), retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), and X-linked juvenile retinoschisis (XLRS). This review also briefly explores the culturing methods of iPSC-derived ROs in recent years. Specifically, it emphasizes the comparison of the similarities between the formation process of ROs and the in-vivo retinal development process. This encompasses aspects such as the formation of different structures, the expression of key markers, and the manifestation of physiological functions. By utilizing the RO disease model to explore the pathogenesis of IRDs and conduct drug screening, it is expected to advance the precision treatment of IRDs and improve the therapeutic outcomes for patients.
2025-08-25 | Therapeutic potential of allogeneic iPS cell-derived RPE transplantation for RPE65-LCA.
To evaluate the safety and therapeutic effects of induced pluripotent stem (iPS) cell-derived retinal pigment epithelium (RPE) transplantation for RPE65-associated Leber congenital amaurosis (RPE65-LCA). A 46-year-old male patient with RPE65-LCA underwent allogeneic iPS cell-derived RPE transplantation. The patient's best-corrected visual acuity (VA) prior to treatment was 2.0 (logMAR). A cell suspension of iPS cell-derived RPE was transplanted into the subretinal space. On day 15 post-transplantation, intraocular pressure (IOP) increased to 46 mmHg due to local steroid treatment, resulting in a decrease in VA to light perception (LP). Retinal imaging on day 71 revealed that most transplanted cells had migrated and formed an epiretinal membrane (ERM). The ERM was surgically removed on day 112. Two years post-transplantation, the patient reported improved vision, with VA improving to 1.4 (logMAR) from LP. Full-field stimulus testing (FST) and microperimetry demonstrated increased retinal sensitivity. These improvements have been maintained for up to 4 years post-treatment. Although this case raised safety concerns regarding the use of cell suspension for RPE transplantation, RPE transplantation may still serve as a potential therapeutic option for patients with RPE65-associated retinopathy, particularly those who are not eligible or older age for RPE65 gene therapy.
2025-06-11 | Biomaterials in Retinal Regeneration
Retinal degenerative diseases, such as age-related macular degeneration, glaucoma, retinitis pigmentosa, Leber congenital amaurosis, and Stargardt macular dystrophy, result in the progressive loss of retinal pigment epithelium, retinal ganglion cells, and photoreceptors. These cells do not proliferate spontaneously, and their death inevitably leads to vision loss. Retinal diseases remain the leading cause of irreversible blindness, affecting hundreds of millions of individuals worldwide. Researchers, aiming to reverse the loss of retinal cells, have developed different approaches with the aim of achieving retinal regeneration. Current retinal regeneration methods, including gene delivery, stem cell transplantation, and tissue engineering, and the role of biomaterials in supporting retinal regenerative treatments will be discussed herein.
2025-05-31 | Generation of two iPSC lines (UGENTi003 and UGENTi004) from patients with intermediate rod-cone dystrophy carrying the c.[-123C>T;701G>A];[806_810del] variants in the RDH12 gene.
Biallelic variants in RDH12 are associated with early-onset retinal dystrophy and Leber congenital amaurosis. RDH12 plays a role in the phototransduction cascade by converting all-trans retinal into all-trans retinol in the photoreceptor inner segments. Induced pluripotent stem cells (iPSCs) were generated and fully characterized from two patients that are compound heterozygous for the RDH12 c.[-123C>T;701G>A];[806_810del], p.[(?;Arg234His)];[(Ala269Glyfs*2)] variants. These iPSC lines can be used for differentiation towards retinal models to evaluate disease mechanisms and novel therapies.
2025-05-25 | CRB1 mutations cause structural and molecular defects in patient-derived retinal pigment epithelium cells.
Mutations in the CRB1 gene can cause retinitis pigmentosa (RP), Leber congenital amaurosis, and other retinopathies, with retinal pigment epithelium (RPE) being a primary affected cell type. However, the effects of CRB1 variants on RPE cells remain poorly defined. Here, for the first time, we report an in vitro model of patient-specific RPE cells carrying the CRB1 mutations (c.2249G > A and c.2809G > A) to study CRB1-associated RP disease. The patient-derived RPE cells exhibited irregular cell morphology, sparse apical microvilli, abnormal tight junctions, and reduced expression of RPE markers. We also observed that impaired barrier function and phagocytosis lead to increased apical-to-basal movement of fluorescent molecules in disease RPE cells. Notably, transcriptomic analysis revealed decreased expression of cell junction-related genes. In addition, aggregated RPE cells on polydimethylsiloxane (PDMS) microwells significantly enhanced RPE phenotype and cell survival, which was associated with anti-epithelial-mesenchymal transition, anti-aging, and anti-apoptosis. In this study, our results reveal that CRB1-mutated RPE cells generated using RP patient-derived iPSCs could recapitulate the genotype-phenotype features of the disease and provide insights into the pathogenesis of CRB1-associated RPE cells. In addition, our study developed a cell aggregation culture method based on PDMS microwell platforms for the production of highly active and mature iPSC-derived RPE cells.
oligonucleotides
2026-06-25 | Ora visual navigation course™ mobility test results in two individuals with CEP290 LCA after intravitreal injection of antisense oligonucleotide.
This study aimed to report the longitudinal Ora Visual Navigation Course (Ora VNC™) mobility test results in two individuals, with CEP290 LCA following intravitreal injections of an antisense oligonucleotide, sepofarsen. Two individuals were enrolled in the Illuminate Phase 3 trial and subsequently in the Post-Trial Access (PTA) program, undergoing Ora VNC™ across 12 visits. Subject 1 was initially randomized to the control (sham) group and switched to treatment from control group from the month 12 visit onwards. This individual passed only a few courses but demonstrated signs of enhanced spatial perception (defined by, among others, the ability to perceive objects' shapes and sizes). FST (full-field stimulus threshold) supported the light sensitivity gain in this subject. In contrast, subject 2, who received treatment since baseline visit, successfully completed mobility tests in all visits with progressive improvement, reaching lower luminance and more challenging contrast settings over time. According to the technicians' report, both subjects demonstrated an increase in perceived obstacle recognition during iterations, which may reflect improvement of mobility-based visual function outcomes. The Ora VNC™ mobility test captured mobility-based visual function gains, including subtle spatial improvements, but may lack sensitivity in individuals with extremely low vision, potentially overlooking small but patient-relevant changes.
2024-12-21 | Non-viral gene therapy for Leber's congenital amaurosis: progress and possibilities.
Leber's congenital amaurosis (LCA) represents a set of rare and pervasive hereditary conditions of the retina that cause severe vision loss starting in early childhood. Targeted treatment intervention has become possible thanks to recent advances in understanding LCA genetic basis. While viral vectors have shown efficacy in gene delivery, they present challenges related to safety, low cargo capacity, and the potential for random genomic integration. Non-viral gene therapy is a safer and more flexible alternative to treating the underlying genetic mutation causing LCA. Non-viral gene delivery methods, such as inorganic nanoparticles, polymer-based delivery systems, and lipid-based nanoparticles, bypass the risks of immunogenicity and genomic integration, potentially offering a more versatile and personalized treatment for patients. This review explores the genetic background of LCA, emphasizing the mutations involved, and explores diverse non-viral gene delivery methods being developed. It also highlights recent studies on non-viral gene therapy for LCA in animal models and clinical trials. It presents future perspectives for gene therapy, including integrating emerging technologies like CRISPR-Cas9, interdisciplinary collaborations, personalized medicine, and ethical considerations.
2024-12-04 | The Future of Nanomaterials Tackling the Challenge of Delivering Nucleic Acids to the Retina
Abstract Ocular gene therapy targets eye diseases at the genetic level. Systemic transport of nucleic acids to ocular tissues poses a significant challenge, as the effectiveness of crossing the blood‐retina barrier limits nucleic acid penetration. Therefore, local administration, such as topical, periocular, or intraocular, can improve the outcome of in vivo gene therapy by bypassing the first‐pass effect and minimizing the systemic toxic effects. The eye is an immune‐privileged organ with limited local immune response, making it an ideal candidate for local gene therapy. Ocular gene therapy offers a promising solution for the treatment of a wide range of retinal diseases including age‐related macular degeneration, diabetic retinopathy, retinitis pigmentosa, and Leber congenital amaurosis. Gene therapy enables replacement of mutated genes essential for visual function, delivery of genes expressing neurotrophic factors and anti‐apoptosis factors for retinal degeneration, and delivery of genes expressing anti‐angiogenic proteins for ocular neovascularization. This perspective discusses the potential of nanoparticles for nucleic acid delivery to the retina, explores challenges, and evaluates different delivery methods, including non‐viral agents such as liposomes and polymers. These nonviral agents present advantages over traditional viral vectors, showing promise in overcoming limitations and offering a viable option for retinal gene therapy.
2024-11-27 | Modern diagnosis and treatment of Leber congenital amaurosis with CEP290 gene
Purpose. Demonstration of a clinical case of Leber congenital amaurosis. Material and methods. This article presents a clinical case of diagnosing Leber congenital amaurosis in a 5-year-old patient. Results. The disease is caused by biallelic loss-offunction mutations in the CEP290 gene (Leber congenital amaurosis type 10), which leads to dysregulation of metabolism within photoreceptor ciliary transport. A heterozygous mutation in the 26th intron of the CEP290 gene (chr12: 88494960T>C, rs281865192) leads to the formation of an alternative splicing site (c.2991+1655A>G, NM_025114.3), which causes the disease in the child. Conclusion. A defective mutation in the CEP290 gene (mutation p.Cys998X, also known as c.2991+1655A>G) has been reported in 57% of Caucasian patients. Clinical manifestations vary from object vision to complete blindness. The prognosis for the development of visual functions is unfavorable. Diagnosis and treatment pose certain difficulties given the decline in visual function with age. Thanks to modern technologies and the active development of clinical genetics, it becomes possible to successfully resolve this disease thanks to the drug sepofarsen (QR-110), which modulates RNA splicing, thereby blocking access to the active site of cryptic splicing and restoring preference for the CEP290 type splicing site, opening new horizons in the treatment of Leber’s amaurosis type 10. Key words: Leber’s amaurosis type 10, sepofarsen, mutation in the CEP290 gene, p.Cys998X mutation, c.2991+1655A>G mutation For citation: Ermolaeva E.V., Sidorenko E.E., Malinovskaya V.S., Rozmetova B.Sh., Suvorova Yu.A., Krapivkin A.I., Loskutova V.E., Grigoriev G.V. Modern diagnosis and treatment of Leber congenital amaurosis with CEP290 gene. Rossiyskaya detskaya oftalmologiya. 2024;4(50): 27–37.
2024-01-18 | The importance of having a relevant model system to investigate splicing modulation in the retina: The unforeseen cases of the intronic variants in RPE65 and IMPG2 genes
Inherited retinal diseases (IRDs) are clinically and genetically heterogeneous disorders that can be caused by pathogenic variants in one of the more than 270 genes associated with IRDs. Among them, mutations in RPE65 can lead to Leber congenital amaurosis (LCA) whereas mutations in IMPG2 to vitelliform macular dystrophy (VMD). During my talk, I will provide evidence of the importance of employing the right cellular models to identify disease mechanism(s) and eventually evaluate suitable treatments. For this, I will highlight two intriguing examples of potential splicing defects studied by our group. Such defects are attractive for splicing modulation therapies using antisense oligonucleotides (AONs), a group of versatile molecules that can alter splicing by interacting with the target sequence(s) at pre‐mRNA level. Thus, characterizing the effect of a variant at the RNA level is instrumental to assess the applicability of AON‐based therapeutic intervention. We explored the effect of the homozygous variant c.11 + 5G>A in RPE65 and a heterozygous complex allele consisting of c.3023‐15T>A and c.3023G>A (p.(Gly1008Asp)) in IMPG2 . In silico predictions suggested that these variants lead to a splicing defect. To assess the pathogenic effect of these variants, splice reporter assays using midigenes were conducted in HEK293T cells. Initial results pointed towards a 124‐nt exon elongation for the RPE65 variant and an in‐frame deletion of 48‐nt at the beginning of exon 15 for the complex allele in IMPG2 . To validate these results, blood cells from the patients harbouring these defects were reprogrammed to induced pluripotent stem cells (iPSCs). Subsequently, iPSCs were differentiated to the retinal cells in which these genes are endogenously expressed. For RPE65 , iPSCs were differentiated into retinal pigment epithelium (RPE) cells (>90 days differentiation) or, for IMPG2 , into photoreceptor precursor cells (PPCs, 30 days differentiation). For the RPE65 variant, a cell specific effect was observed: while a clear exon elongation was observed in the midigene system, in RPE, the expression of the gene was highly reduced. In addition, no protein was detected and the patient‐derived cells showed differences compared to the control line. For IMPG2 , the 48‐nt deletion was detected in a lower percentage in patient‐derived PPCs compared to the levels observed in the midigene system. However, aberrantly spliced IMPG2 transcripts were highly elevated in patient‐derived PPCs in comparison to control PPCs. Overall, our work shows the importance of having the right cellular context to determine the effect of genetic variants on splicing in the retina.
other
2024-07-31 | Leukemia Inhibitory Factor Protects against Degeneration of Cone Photoreceptors Caused by RPE65 Deficiency.
Retinal pigment epithelium (RPE) 65 is a key enzyme in the visual cycle involved in the regeneration of 11-cis-retinal. Mutations in the human RPE65 gene cause Leber's congenital amaurosis (LCA), a severe form of an inherited retinal disorder. Animal models carrying Rpe65 mutations develop early-onset retinal degeneration. In particular, the cones degenerate faster than the rods. To date, gene therapy has been used successfully to treat RPE65-associated retinal disorders. However, gene therapy does not completely prevent progressive retinal degeneration in patients, possibly due to the vulnerability of cones in these patients. In the present study, we tested whether leukemia inhibitory factor (LIF), a trophic factor, protects cones in rd12 mice harboring a nonsense mutation in Rpe65. LIF was administered to rd12 mice by intravitreal microinjection. Apoptosis of retinal cells was analyzed by TUNEL assay. The degeneration of cone cells was evaluated by immunostaining of retinal sections and retinal flat-mounts. Signaling proteins regulated by LIF in the retinal and cultured cells were determined by immunoblotting. Intravitreal administration of LIF activated the STAT3 signaling pathway, thereby inhibiting photoreceptor apoptosis and preserving cones in rd12 mice. Niclosamide (NCL), an inhibitor of STAT3 signaling, effectively blocked STAT3 signaling and autophagy in cultured 661W cells treated with LIF. Co-administration of LIF with NCL to rd12 mice abolished the protective effect of LIF, suggesting that STAT3 signaling and autophagy mediate the protection. LIF is a potent factor that protects cones in rd12 mice. This finding implies that LIF can be used in combination with gene therapy to achieve better therapeutic outcomes for patients with RPE65-associated LCA.
2023-07-17 | Hydrogen peroxide-induced oxidative damage and protective role of peroxiredoxin 6 protein via EGFR/ERK signaling pathway in RPE cells
Introduction Damage to retinal pigment epithelium (RPE) cells caused by oxidative stress is closely related to the pathogenesis of several blinding retinal diseases, such as age-related macular degeneration (AMD), retinitis pigmentosa, and other inherited retinal degenerative conditions. However, the mechanisms of this process are poorly understood. Hence, the goal of this study was to investigate hydrogen peroxide (H 2 O 2 )-induced oxidative damage and protective role of peroxiredoxin 6 (PRDX6) protein via EGFR/ERK signaling pathway in RPE cells. Methods Cells from a human RPE cell line (ARPE-19 cells) were treated with H 2 O 2 , and then cell viability was assessed using the methyl thiazolyl tetrazolium assay. Cell death and reactive oxygen species (ROS) were detected by flow cytometry. The levels of PRDX6, epidermal growth factor receptor (EGFR), P38 mitogen-activated protein kinase (P38MAPK), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) were detected by Western blot assay. PRDX6 and EGFR were also detected via immunofluorescence staining. Results Our results show that H 2 O 2 inhibited cell viability, induced cell death, and increased ROS levels in ARPE-19 cells. It was also found that H 2 O 2 decreased the levels of PRDX6, EGFR, and phosphorylated ERK but increased the levels of phosphorylated P38MAPK and JNK. PRDX6 overexpression was found to attenuate H 2 O 2 -induced inhibition of cell viability and increased cell death and ROS production in ARPE-19 cells. PRDX6 overexpression also increased the expression of EGFR and alleviated the H 2 O 2 -induced decrease in EGFR and phosphorylated ERK. Moreover, inhibition of epidermal growth factor-induced EGFR and ERK signaling in oxidative stress was partially blocked by PRDX6 overexpression. Discussion Our findings indicate that PRDX6 overexpression protects RPE cells from oxidative stress damage caused by decreasing ROS production and partially blocking the inhibition of the EGFR/ERK signaling pathway induced by oxidative stress. Therefore, PRDX6 shows promise as a therapeutic target for the prevention of RPE cell damage caused by oxidative stress associated with retinal diseases.
2021-05-19 | Delivery Systems of Retinoprotective Proteins in the Retina
Retinoprotective proteins play important roles for retinal tissue integrity. They can directly affect the function and the survival of photoreceptors, and/or indirectly target the retinal pigment epithelium (RPE) and endothelial cells that support these tissues. Retinoprotective proteins are used in basic, translational and in clinical studies to prevent and treat human retinal degenerative disorders. In this review, we provide an overview of proteins that protect the retina and focus on pigment epithelium-derived factor (PEDF), and its effects on photoreceptors, RPE cells, and endothelial cells. We also discuss delivery systems such as pharmacologic and genetic administration of proteins to achieve photoreceptor survival and retinal tissue integrity.
2021-01-20 | An In-Silico Study on the Most Effective Growth Factors in Retinal Regeneration Utilizing Tissue Engineering Concepts
Purpose: Considering the significance of retinal disorders and the growing need to employ tissue engineering in this field, in-silico studies can be used to establish a cost-effective method. This in-silico study was performed to find the most effective growth factors contributing to retinal tissue engineering.
Methods: In this study, a regeneration gene database was used. All 21 protein-coding genes participating in retinal regeneration were considered as a protein–protein interaction (PPI) network via the “STRING App” in “Cytoscape 3.7.2” software. The resultant graph possessed 21 nodes as well as 37 edges. Gene ontology (GO) analysis, as well as the centrality analysis, revealed the most effective proteins in retinal regeneration.
Results: According to the biological processes and the role of each protein in different pathways, selecting the correct one is possible through the information that the network provides. Eye development, detection of the visible light, visual perception, photoreceptor cell differentiation, camera-type eye development, eye morphogenesis, and angiogenesis are the major biological processes in retinal regeneration. Based on the GO analysis, SHH, STAT3, FGFR1, OPN4, ITGAV, RAX, and RPE65 are effective in retinal regeneration via the biological processes. In addition, based on the centrality analysis, four proteins have the greatest influence on retinal regeneration: SHH, IGF1, STAT3, and ASCL1.
Conclusion: With the intention of applying the most impressive growth factors in retinal engineering, it seems logical to pay attention to SHH, STAT3, and RPE65. Utilizing these proteins can lead to fabricate high efficiency engineered retina via all aforementioned biological processes.
2019-05-10 | The Role of FGF9 in the Production of Neural Retina and RPE in a Pluripotent Stem Cell Model of Early Human Retinal Development
Purpose
To investigate the role of fibroblast growth factors (FGFs) in the production of neural retina (NR) and retinal pigmented epithelium (RPE) in a human pluripotent stem cell model of early retinal development.
Methods
Human induced pluripotent stem cell (hiPSC) lines from an individual with microphthalmia caused by a functional null mutation (R200Q) in visual system homeobox 2 (VSX2), a transcription factor involved in early NR progenitor cell (NRPC) production, and a normal sibling were differentiated along the retinal and forebrain lineages using an established protocol. Quantitative and global gene expression analyses (microarray and RNAseq) were used to investigate endogenous FGF expression profiles in these cultures over time. Based on these results, mutant and control hiPSC cultures were treated exogenously with selected FGFs and subjected to gene and protein expression analyses to determine their effects on RPE and NR production.
Results
We found that FGF9 and FGF19 were selectively increased in early hiPSC-derived optic vesicles (OVs) when compared to isogenic cultures of hiPSC-derived forebrain neurospheres. Furthermore, these same FGFs were downregulated over time in (R200Q)VSX2 hiPSC-OVs relative to sibling control hiPSC-OVs. Interestingly, long-term supplementation with FGF9, but not FGF19, partially rescued the mutant retinal phenotype of the (R200Q)VSX2 hiPSC-OV model. However, antagonizing FGF9 in wild-type control hiPSCs did not alter OV development.
Conclusions
Our results show that FGF9 acts in concert with VSX2 to promote NR differentiation in hiPSC-OVs and has potential to be used to manipulate early retinogenesis and mitigate ocular defects caused by functional loss of VSX2 activity. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.
small molecules
2026-06-25 | Programmed axon degeneration gene variants in human disease.
Programmed axon degeneration (PAD; also known as Wallerian degeneration) is a conserved pathway controlling axon breakdown following injury or metabolic stress. PAD is driven by the depletion of nicotinamide adenine dinucleotide (NAD) through loss of the pro-survival enzyme NMNAT2 and activation of the pro-degenerative NADase SARM1. Recent genetic studies have identified pathogenic variants in PAD pathway enzymes associated with severe neurodegenerative phenotypes. Pathogenic variants in NAMPT, NMNAT1, NMNAT2, and SARM1 have been identified and will be discussed in this review. NAMPT variants cause sensory and motor neuropathy with neurodevelopmental symptoms. NMNAT1 variants are well-characterized causes of Leber Congenital Amaurosis type 9, while NMNAT2 variants result in peripheral neuropathies with childhood onset. SARM1 gain-of-function variants with constitutively active NADase activity are enriched in amyotrophic lateral sclerosis patients. These findings demonstrate that maintaining proper NAD homeostasis is crucial for axon survival, and disruption through genetic variants leads to distinct neurodegenerative outcomes. Understanding these rare variants provides insight into PAD mechanisms and supports development of broad-spectrum neuroprotective therapies targeting this pathway. Current therapeutic approaches include SARM1 inhibitors in clinical trials, gene therapy, and NAD precursor supplementation, offering hope for treating multiple neurodegenerative diseases.
2026-05-25 | Halofantrine protects photoreceptors in multiple models of retinal degeneration.
Inherited retinal degenerative diseases (IRDs), including retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), cause progressive vision impairment due to photoreceptor degeneration. We previously demonstrated the protective effects of reserpine in models of CEP290-LCA and in the female Rhodopsin-P23H rat model of autosomal dominant RP. Given that reserpine is limited by side effects, we expanded our compound screen using retinal organoids from the rd16 mouse model of CEP290-LCA to include structurally diverse small molecules that may converge on proteostasis pathways. Follow-up evaluations in Rhodopsin-P23H rats, human CEP290-LCA retinal organoids, and rd10 mice (a model of PDE6B-RP) identified halofantrine as the most promising molecule, conferring strong protection to both rod and cone photoreceptors and demonstrating therapeutic potential across the divergent IRD models tested. Transcriptome analysis revealed a convergent molecular response to halofantrine across these models, primarily through upregulation of oxidative phosphorylation and ribosomal processes. Notably, halofantrine elicited significant improvements in retinal function, as assessed by electroretinography, despite pharmacokinetically limited and transient retinal exposure after subconjunctival injection in Rhodopsin-P23H rats. Our studies highlight the potential of halofantrine as a gene-independent therapy and suggest that it may be developed for ocular delivery via eye drops for the treatment of IRDs.
2026-04-02 | Oxidative DNA damage drives apoptotic photoreceptor loss in NMNAT1-associated inherited retinal degeneration: a therapeutic opportunity.
Early-onset inherited retinal degenerations (IRDs), such as Leber congenital amaurosis (LCA) caused by pathogenic variants in the NMNAT1 gene, lead to severe vision loss in children. Despite its ubiquitous expression, reduced NMNAT1 function primarily affects photoreceptor cells (PRs) of the retina, yet the mechanisms underlying their vulnerability remain incompletely understood. Here, we demonstrate that reduced NMNAT1 enzyme function due to the p.V9M mutation leads to DNA damage in PRs, characterized by the progressive accumulation of the oxidative DNA adduct 8-oxo-dG in Nmnat1V9M/V9M mutant mice. Cells with oxidative DNA damage also demonstrate DNA double-strand breaks, as evidenced by co-staining with antibodies to phosphorylated H2AX (γH2A.X). This DNA damage correlates with apoptosis-driven PR degeneration, as evidenced by caspase-9 activation and TUNEL staining in the PRs of the Nmnat1V9M/V9M mutant mice, while alternative cell death pathways such as necroptosis and parthanatos were not significantly activated. Treatment with the antioxidant N-acetylcysteine (NAC) reduced oxidative DNA damage and retinal immune responses, mitigated apoptosis, and preserved cone PRs. Longitudinal assessment via optical coherence tomography (OCT) and electroretinography (ERG) revealed sustained structural and functional protection of the retina in NAC-treated mice. These findings establish oxidative DNA damage as a key driver of PR degeneration in the Nmnat1V9M/V9M model and highlight NAC's potential as a therapeutic strategy for NMNAT1-associated IRD and potentially other IRDs in which oxidative DNA damage contributes to disease pathogenesis.
2025-12-04 | Early-Onset Retinopathy in Patients With Variants in SLC6A6 Leading to Impaired Taurine Transport.
Inherited retinal dystrophies are a group of disorders that may lead to progressive vision loss. Improved knowledge of their molecular genetics is important for accurate diagnosis or development of targeted therapies. To identify pathogenic variants in the SLC6A6 gene (encoding TauT, the main transporter for taurine) and assess their role in the molecular pathogenesis of hereditary early-onset retinal dystrophy (EORD) in affected individuals from diverse ethnic backgrounds. This was a retrospective, multicenter observational study conducted between June 2019 and March 2025, involving 7 affected and 10 unaffected individuals from 4 unrelated families recruited in Pakistan, Italy, the US, and France. Pathogenic variants in SLC6A6 in individuals with EORD. Genetic, clinical, and functional outcomes of pathogenic variants in SLC6A6 in individuals with Leber congenital amaurosis (LCA) and EORD. All patients underwent standard clinical examinations, including visual acuity, full-field electroretinography, and multimodal retinal imaging, followed by measurement of fasting plasma taurine levels. In vitro and ex vivo taurine transport and membrane trafficking assays in human embryonic kidney (HEK)-293 cells, as well as patient-derived fibroblasts, were also performed. All 7 affected individuals exhibited LCA/EORD, with extraocular findings in some. Genetic analysis identified homozygous pathogenic SLC6A6 variants in all affected individuals, while unaffected relatives were heterozygous carriers. Families 1 and 2 carried missense variants p.(Thr249Ile) and p.(Ala294Thr), while families 3 and 4 carried truncating variants-a deletion of exon 11 and p.(Thr113Ter), respectively. Functional studies demonstrated that both missense variants are associated with complete loss of taurine transport in HEK-293 cells and patient-derived fibroblasts. Additionally, irrespective of the variants considered, plasma taurine levels in affected individuals were reduced compared with heterozygous carriers (difference between means, -31.7 µmol/L; 95% CI, -42.7 to -20.8; P < .001) and healthy control individuals (difference between means, -37.7 µmol/L; 95% CI -41.6 to -33.8; P < .001). These findings confirm and expand the role of biallelic variants in SLC6A6 in association with LCA/EORD due to impaired taurine transport. These findings suggest that patients with a diagnosis of SLC6A6-related LCA/EORD may be candidates for investigational oral taurine supplementation.
2025-12-01 | Mechanisms and Functions of Chromophore Regeneration in the Classical Visual Cycle: Implications for Retinal Disease Pathogenesis and Therapy
11-cis-retinal, the indispensable chromophore of photoreceptor opsins, is fundamental for light detection and the initiation of visual signal transduction. Its synthesis and regeneration through the visual cycle are critical not only for phototransduction but also for maintaining retinal homeostasis. Disruption of key enzymes, such as retinal pigment epithelium (RPE)65 and retinol dehydrogenases, results in toxic retinoid accumulation, oxidative stress, and progressive photoreceptor degeneration. These pathological mechanisms contribute to inherited and acquired retinal diseases, including Stargardt disease type 1, age-related macular degeneration, Leber congenital amaurosis, retinitis pigmentosa, and fundus albipunctatus. Recent therapeutic advances, ranging from gene replacement therapy with RPE65 (voretigene neparvovec, Luxturna®) to small-molecule modulators and antioxidant strategies, underscore the translational potential of targeting chromophore metabolism. This review outlines molecular processes underlying chromophore synthesis and regeneration, elucidates how disruptions in these processes contribute to inherited and acquired retinal pathologies, and evaluates existing and emerging therapeutic strategies that target chromophore metabolism. We highlight ongoing challenges and critical knowledge gaps to guide future investigations on basic science, translational research, and clinical practice. This review provides a comprehensive overview of the molecular mechanisms, current therapeutic approaches, and outstanding challenges, with a focus on future intervention directions.
gene therapies
2026-09-25 | Clinical translation of CRISPR-Cas9 therapeutics in cancer and inherited genetic disorders.
CRISPR-Cas9, adapted from the bacterial Type II CRISPR adaptive immune system, functions as a programmable RNA-guided endonuclease that employs a single-guide RNA to direct Cas9 to specific genomic loci. CRISPR-Cas9 has transformed targeted genome editing by replacing complex protein engineering with programmable Watson-Crick base pairing between the guide RNA and target DNA. This review was developed following a structured literature search of major biomedical databases and clinical trial registries to synthesize current evidence on the therapeutic applications of CRISPR-Cas9 in oncology and inherited genetic disorders. Clinical studies of ex vivo BCL11A-enhancer editing have shown fetal hemoglobin reactivation, with most evaluable participants with sickle cell disease remaining free of severe vaso-occlusive crises for the prespecified period and most evaluable participants with transfusion-dependent β-thalassemia achieving sustained transfusion independence. In vivo reductions in circulating transthyretin protein levels have been achieved for transthyretin amyloidosis via lipid nanoparticle delivery, while clinically meaningful improvements in selected measures of visual function were observed in a subset of patients receiving subretinal AAV-delivered CRISPR editing for CEP290-associated Leber congenital amaurosis type 10. Preclinical and early clinical studies have further investigated CRISPR-engineered T cells designed to improve antitumor activity, persistence, or resistance to inhibitory signaling. Despite these advances, key translational hurdles include the risk of off-target mutations and large-scale chromosomal rearrangements. Furthermore, immune responses against bacterial Cas9 nucleases and viral delivery vectors may limit the long-term efficacy of CRISPR-based therapies, while technical barriers surrounding delivery to extrahepatic tissues, such as skeletal muscle and the central nervous system, continue to hinder broader clinical success. Ethical concerns regarding germline modifications and the high cost of individualized therapies present additional translational challenges. Consequently, emerging DSB-independent technologies, such as base editing and prime editing, may reduce selected DSB-associated liabilities, but each introduces distinct editing, delivery, and genotoxicity risks that require product-specific evaluation.
2026-08-21 | Gene therapy clinical trials for inherited eye diseases: The pediatric perspective.
Gene therapy is an increasingly useful treatment option, especially in children, where most inherited diseases manifest. This review provides a literature synthesis of current gene therapy treatments in pediatric ophthalmology. Our search encompassed the ClinicalTrials.gov database. Sixteen clinical trials with published results reporting gene therapy for genetic ocular diseases in children (under 18 years) were included. Diseases under investigation for gene therapy in children included Leber's Congenital Amaurosis (CEP290, RPE65 genes), Leber's Hereditary Optic Neuropathy (ND4), Retinitis Pigmentosa (MERTK), Usher Syndrome Type 2 (USH2A), X-linked Retinitis Pigmentosa (RPGR), Achromatopsia (CNGA3, CNGB3), and X-linked Retinoschisis (RS1). Most clinical trials in our search were in Phases 1 or 2, with five studies having progressed to Phase 3. In certain cases, treatment demonstrated encouraging results, providing the patients with an improvement in BCVA, retinal sensitivity, and quality of life. However, the outcome measures regarding the efficacy and tolerability of gene therapy varied and some studies noted adverse events. Clinical trials that have yet to publish their results were also recorded. While the field of pediatric ophthalmology shows promise for gene therapy options, future strategies should include stratified enrollment based on age, separate cohorts for pediatric and adult patients, or adaptive trial designs.
2026-06-23 | Trends in the Engineering of Adeno-Associated Virus (AAV) for Precision Gene Delivery to the Central Nervous System (CNS)
Rare genetic disorders of the central nervous system (CNS) remain some of the most complex and challenging diseases to treat for several reasons. Targeting the CNS, especially the brain, presents one of the greatest obstacles in gene therapy using adeno-associated virus (AAV) vectors. Although various AAVs have been identified for their ability to transduce different cells in the CNS, their effectiveness and efficiency are significantly limited by the presence of neutralising antibodies (NAbs) and restricted cargo capacity. Despite these challenges, our understanding of AAV structure and technological advances continue to enable researchers to develop innovative strategies that have resulted in groundbreaking, FDA-approved therapeutic products now available for Leber congenital amaurosis (LCA) (Luxturna®), spinal muscular atrophy (SMA) (Zolgensma®), and the two recent gene therapy products for aromatic L-amino acid decarboxylase (AADC) deficiency, Kebilidi® and Upstaza®, which currently hold FDA and EMA approval, respectively. This review aims to highlight recent advances in the field of AAV gene therapy for neurological disorders, identify research gaps, and suggest areas for future investigation to enable potential breakthroughs particularly in neurodegenerative, neurodevelopmental, and neuromuscular disorders. We foresee that more tissue- and cell-specific AAV vectors designed using AI-powered platforms will emerge to precisely and efficiently target specific brain regions, transforming how CNS disorders are treated.
2026-06-13 | Therapeutic applications of gene editing using CRISPR-Cas9 in the posterior segment: review of the literature.
CRISPR-Cas gene editing has become increasingly relevant in the treatment of several ophthalmic diseases. Its ability to make precise modifications at the DNA or RNA level has enabled targeted approaches for specific mutations involved in conditions such as Leber congenital amaurosis type 10 (LCA10), certain forms of retinitis pigmentosa, and age-related macular degeneration. This article provides an organized overview of the biological basis of CRISPR-Cas technology and highlights key advances from preclinical studies and early clinical trials. Technical limitations and ongoing safety challenges are also discussed. Programs such as EDIT-101, EDIT-103, and HG202 stand out as important milestones in the evolution of ocular gene editing.
2026-05-20 | Synonymous editing alters ion channel function, favoring prime editing for retinal disease correction.
Point mutations in the KCNJ13 gene cause autosomal recessive childhood blindness, Leber congenital amaurosis (LCA16), by disrupting Kir7.1 channel function. We describe the etiology of the LCA16 retinopathy phenotype in three patients from two unrelated families harboring a homozygous KCNJ13 missense mutation (c.431T>C, p.Leu144Pro). Our in silico prediction and in vitro validation using a human iPSC-derived retinal pigmented epithelium (RPE) model created via lipid nanoparticle-mediated delivery of the adenine base editor (ABE8e) demonstrated that the L144P mutation impairs Kir7.1 channel function and confirmed that non-viral biologic delivery is clinically translatable. We used two cytosine base editors (CBEs, BE4max-WTCas9 and evoCDA-SpCas9-NG) to correct this mutation in an L144P HEK293 stable cell model, achieving high on-target editing efficiency. However, our electrophysiological measurements showed minimal functional rescue of the channel in CBE-edited cells due to bystander nucleotide editing. Editing with evoCDA introduced a bystander missense mutation (L143F), whereas BE4max primarily generated silent mutations. Extended characterization of BE4max-edited cells revealed a distorted mRNA structure, altered half-life, and reduced abundance of cognate tRNA, all associated with these silent changes. In contrast, prime editing successfully restored channel function. Prime editors targeting the L144P locus achieved approximately 20% on-target editing without introducing bystander nucleotide editing or synonymous changes. Functional assessment demonstrated a strong genotype-phenotype correlation, with restored Kir7.1 channel activity observed in 28% of edited cells (12/43). Overall, these results highlight the importance of comprehensive functional validation of genome editing outcomes and emphasize the need for rigorous preclinical studies to translate therapeutic genome editing into first-in-human trials for genetically diverse diseases.
cell therapies
2025-11-01 | Progress of iPSC-derived retinal organoids in the study of inherited retinal diseases.
Inherited retinal diseases (IRDs) constitute a complex and heterogeneous group of rare disorders characterized by significant genetic diversity. These conditions often lead to the degeneration of photoreceptor cells, resulting in severe visual impairment. A major challenge in the study and treatment of IRDs is the lack of appropriate preclinical models for investigating their pathogenesis and evaluating potential therapeutic interventions. In recent years, advances in retinal organoids (ROs) culture technology have provided promising new avenues for IRDs. This review systematically elaborates on the applications of induced pluripotent stem cells (iPSC)-derived ROs as disease models in IRDs such as retinoblastoma (RB), retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), and X-linked juvenile retinoschisis (XLRS). This review also briefly explores the culturing methods of iPSC-derived ROs in recent years. Specifically, it emphasizes the comparison of the similarities between the formation process of ROs and the in-vivo retinal development process. This encompasses aspects such as the formation of different structures, the expression of key markers, and the manifestation of physiological functions. By utilizing the RO disease model to explore the pathogenesis of IRDs and conduct drug screening, it is expected to advance the precision treatment of IRDs and improve the therapeutic outcomes for patients.
2025-08-25 | Therapeutic potential of allogeneic iPS cell-derived RPE transplantation for RPE65-LCA.
To evaluate the safety and therapeutic effects of induced pluripotent stem (iPS) cell-derived retinal pigment epithelium (RPE) transplantation for RPE65-associated Leber congenital amaurosis (RPE65-LCA). A 46-year-old male patient with RPE65-LCA underwent allogeneic iPS cell-derived RPE transplantation. The patient's best-corrected visual acuity (VA) prior to treatment was 2.0 (logMAR). A cell suspension of iPS cell-derived RPE was transplanted into the subretinal space. On day 15 post-transplantation, intraocular pressure (IOP) increased to 46 mmHg due to local steroid treatment, resulting in a decrease in VA to light perception (LP). Retinal imaging on day 71 revealed that most transplanted cells had migrated and formed an epiretinal membrane (ERM). The ERM was surgically removed on day 112. Two years post-transplantation, the patient reported improved vision, with VA improving to 1.4 (logMAR) from LP. Full-field stimulus testing (FST) and microperimetry demonstrated increased retinal sensitivity. These improvements have been maintained for up to 4 years post-treatment. Although this case raised safety concerns regarding the use of cell suspension for RPE transplantation, RPE transplantation may still serve as a potential therapeutic option for patients with RPE65-associated retinopathy, particularly those who are not eligible or older age for RPE65 gene therapy.
2025-06-11 | Biomaterials in Retinal Regeneration
Retinal degenerative diseases, such as age-related macular degeneration, glaucoma, retinitis pigmentosa, Leber congenital amaurosis, and Stargardt macular dystrophy, result in the progressive loss of retinal pigment epithelium, retinal ganglion cells, and photoreceptors. These cells do not proliferate spontaneously, and their death inevitably leads to vision loss. Retinal diseases remain the leading cause of irreversible blindness, affecting hundreds of millions of individuals worldwide. Researchers, aiming to reverse the loss of retinal cells, have developed different approaches with the aim of achieving retinal regeneration. Current retinal regeneration methods, including gene delivery, stem cell transplantation, and tissue engineering, and the role of biomaterials in supporting retinal regenerative treatments will be discussed herein.
2025-05-31 | Generation of two iPSC lines (UGENTi003 and UGENTi004) from patients with intermediate rod-cone dystrophy carrying the c.[-123C>T;701G>A];[806_810del] variants in the RDH12 gene.
Biallelic variants in RDH12 are associated with early-onset retinal dystrophy and Leber congenital amaurosis. RDH12 plays a role in the phototransduction cascade by converting all-trans retinal into all-trans retinol in the photoreceptor inner segments. Induced pluripotent stem cells (iPSCs) were generated and fully characterized from two patients that are compound heterozygous for the RDH12 c.[-123C>T;701G>A];[806_810del], p.[(?;Arg234His)];[(Ala269Glyfs*2)] variants. These iPSC lines can be used for differentiation towards retinal models to evaluate disease mechanisms and novel therapies.
2025-05-25 | CRB1 mutations cause structural and molecular defects in patient-derived retinal pigment epithelium cells.
Mutations in the CRB1 gene can cause retinitis pigmentosa (RP), Leber congenital amaurosis, and other retinopathies, with retinal pigment epithelium (RPE) being a primary affected cell type. However, the effects of CRB1 variants on RPE cells remain poorly defined. Here, for the first time, we report an in vitro model of patient-specific RPE cells carrying the CRB1 mutations (c.2249G > A and c.2809G > A) to study CRB1-associated RP disease. The patient-derived RPE cells exhibited irregular cell morphology, sparse apical microvilli, abnormal tight junctions, and reduced expression of RPE markers. We also observed that impaired barrier function and phagocytosis lead to increased apical-to-basal movement of fluorescent molecules in disease RPE cells. Notably, transcriptomic analysis revealed decreased expression of cell junction-related genes. In addition, aggregated RPE cells on polydimethylsiloxane (PDMS) microwells significantly enhanced RPE phenotype and cell survival, which was associated with anti-epithelial-mesenchymal transition, anti-aging, and anti-apoptosis. In this study, our results reveal that CRB1-mutated RPE cells generated using RP patient-derived iPSCs could recapitulate the genotype-phenotype features of the disease and provide insights into the pathogenesis of CRB1-associated RPE cells. In addition, our study developed a cell aggregation culture method based on PDMS microwell platforms for the production of highly active and mature iPSC-derived RPE cells.
oligonucleotides
2026-06-25 | Ora visual navigation course™ mobility test results in two individuals with CEP290 LCA after intravitreal injection of antisense oligonucleotide.
This study aimed to report the longitudinal Ora Visual Navigation Course (Ora VNC™) mobility test results in two individuals, with CEP290 LCA following intravitreal injections of an antisense oligonucleotide, sepofarsen. Two individuals were enrolled in the Illuminate Phase 3 trial and subsequently in the Post-Trial Access (PTA) program, undergoing Ora VNC™ across 12 visits. Subject 1 was initially randomized to the control (sham) group and switched to treatment from control group from the month 12 visit onwards. This individual passed only a few courses but demonstrated signs of enhanced spatial perception (defined by, among others, the ability to perceive objects' shapes and sizes). FST (full-field stimulus threshold) supported the light sensitivity gain in this subject. In contrast, subject 2, who received treatment since baseline visit, successfully completed mobility tests in all visits with progressive improvement, reaching lower luminance and more challenging contrast settings over time. According to the technicians' report, both subjects demonstrated an increase in perceived obstacle recognition during iterations, which may reflect improvement of mobility-based visual function outcomes. The Ora VNC™ mobility test captured mobility-based visual function gains, including subtle spatial improvements, but may lack sensitivity in individuals with extremely low vision, potentially overlooking small but patient-relevant changes.
2024-12-21 | Non-viral gene therapy for Leber's congenital amaurosis: progress and possibilities.
Leber's congenital amaurosis (LCA) represents a set of rare and pervasive hereditary conditions of the retina that cause severe vision loss starting in early childhood. Targeted treatment intervention has become possible thanks to recent advances in understanding LCA genetic basis. While viral vectors have shown efficacy in gene delivery, they present challenges related to safety, low cargo capacity, and the potential for random genomic integration. Non-viral gene therapy is a safer and more flexible alternative to treating the underlying genetic mutation causing LCA. Non-viral gene delivery methods, such as inorganic nanoparticles, polymer-based delivery systems, and lipid-based nanoparticles, bypass the risks of immunogenicity and genomic integration, potentially offering a more versatile and personalized treatment for patients. This review explores the genetic background of LCA, emphasizing the mutations involved, and explores diverse non-viral gene delivery methods being developed. It also highlights recent studies on non-viral gene therapy for LCA in animal models and clinical trials. It presents future perspectives for gene therapy, including integrating emerging technologies like CRISPR-Cas9, interdisciplinary collaborations, personalized medicine, and ethical considerations.
2024-12-04 | The Future of Nanomaterials Tackling the Challenge of Delivering Nucleic Acids to the Retina
Abstract Ocular gene therapy targets eye diseases at the genetic level. Systemic transport of nucleic acids to ocular tissues poses a significant challenge, as the effectiveness of crossing the blood‐retina barrier limits nucleic acid penetration. Therefore, local administration, such as topical, periocular, or intraocular, can improve the outcome of in vivo gene therapy by bypassing the first‐pass effect and minimizing the systemic toxic effects. The eye is an immune‐privileged organ with limited local immune response, making it an ideal candidate for local gene therapy. Ocular gene therapy offers a promising solution for the treatment of a wide range of retinal diseases including age‐related macular degeneration, diabetic retinopathy, retinitis pigmentosa, and Leber congenital amaurosis. Gene therapy enables replacement of mutated genes essential for visual function, delivery of genes expressing neurotrophic factors and anti‐apoptosis factors for retinal degeneration, and delivery of genes expressing anti‐angiogenic proteins for ocular neovascularization. This perspective discusses the potential of nanoparticles for nucleic acid delivery to the retina, explores challenges, and evaluates different delivery methods, including non‐viral agents such as liposomes and polymers. These nonviral agents present advantages over traditional viral vectors, showing promise in overcoming limitations and offering a viable option for retinal gene therapy.
2024-11-27 | Modern diagnosis and treatment of Leber congenital amaurosis with CEP290 gene
Purpose. Demonstration of a clinical case of Leber congenital amaurosis. Material and methods. This article presents a clinical case of diagnosing Leber congenital amaurosis in a 5-year-old patient. Results. The disease is caused by biallelic loss-offunction mutations in the CEP290 gene (Leber congenital amaurosis type 10), which leads to dysregulation of metabolism within photoreceptor ciliary transport. A heterozygous mutation in the 26th intron of the CEP290 gene (chr12: 88494960T>C, rs281865192) leads to the formation of an alternative splicing site (c.2991+1655A>G, NM_025114.3), which causes the disease in the child. Conclusion. A defective mutation in the CEP290 gene (mutation p.Cys998X, also known as c.2991+1655A>G) has been reported in 57% of Caucasian patients. Clinical manifestations vary from object vision to complete blindness. The prognosis for the development of visual functions is unfavorable. Diagnosis and treatment pose certain difficulties given the decline in visual function with age. Thanks to modern technologies and the active development of clinical genetics, it becomes possible to successfully resolve this disease thanks to the drug sepofarsen (QR-110), which modulates RNA splicing, thereby blocking access to the active site of cryptic splicing and restoring preference for the CEP290 type splicing site, opening new horizons in the treatment of Leber’s amaurosis type 10. Key words: Leber’s amaurosis type 10, sepofarsen, mutation in the CEP290 gene, p.Cys998X mutation, c.2991+1655A>G mutation For citation: Ermolaeva E.V., Sidorenko E.E., Malinovskaya V.S., Rozmetova B.Sh., Suvorova Yu.A., Krapivkin A.I., Loskutova V.E., Grigoriev G.V. Modern diagnosis and treatment of Leber congenital amaurosis with CEP290 gene. Rossiyskaya detskaya oftalmologiya. 2024;4(50): 27–37.
2024-01-18 | The importance of having a relevant model system to investigate splicing modulation in the retina: The unforeseen cases of the intronic variants in RPE65 and IMPG2 genes
Inherited retinal diseases (IRDs) are clinically and genetically heterogeneous disorders that can be caused by pathogenic variants in one of the more than 270 genes associated with IRDs. Among them, mutations in RPE65 can lead to Leber congenital amaurosis (LCA) whereas mutations in IMPG2 to vitelliform macular dystrophy (VMD). During my talk, I will provide evidence of the importance of employing the right cellular models to identify disease mechanism(s) and eventually evaluate suitable treatments. For this, I will highlight two intriguing examples of potential splicing defects studied by our group. Such defects are attractive for splicing modulation therapies using antisense oligonucleotides (AONs), a group of versatile molecules that can alter splicing by interacting with the target sequence(s) at pre‐mRNA level. Thus, characterizing the effect of a variant at the RNA level is instrumental to assess the applicability of AON‐based therapeutic intervention. We explored the effect of the homozygous variant c.11 + 5G>A in RPE65 and a heterozygous complex allele consisting of c.3023‐15T>A and c.3023G>A (p.(Gly1008Asp)) in IMPG2 . In silico predictions suggested that these variants lead to a splicing defect. To assess the pathogenic effect of these variants, splice reporter assays using midigenes were conducted in HEK293T cells. Initial results pointed towards a 124‐nt exon elongation for the RPE65 variant and an in‐frame deletion of 48‐nt at the beginning of exon 15 for the complex allele in IMPG2 . To validate these results, blood cells from the patients harbouring these defects were reprogrammed to induced pluripotent stem cells (iPSCs). Subsequently, iPSCs were differentiated to the retinal cells in which these genes are endogenously expressed. For RPE65 , iPSCs were differentiated into retinal pigment epithelium (RPE) cells (>90 days differentiation) or, for IMPG2 , into photoreceptor precursor cells (PPCs, 30 days differentiation). For the RPE65 variant, a cell specific effect was observed: while a clear exon elongation was observed in the midigene system, in RPE, the expression of the gene was highly reduced. In addition, no protein was detected and the patient‐derived cells showed differences compared to the control line. For IMPG2 , the 48‐nt deletion was detected in a lower percentage in patient‐derived PPCs compared to the levels observed in the midigene system. However, aberrantly spliced IMPG2 transcripts were highly elevated in patient‐derived PPCs in comparison to control PPCs. Overall, our work shows the importance of having the right cellular context to determine the effect of genetic variants on splicing in the retina.
other
2024-07-31 | Leukemia Inhibitory Factor Protects against Degeneration of Cone Photoreceptors Caused by RPE65 Deficiency.
Retinal pigment epithelium (RPE) 65 is a key enzyme in the visual cycle involved in the regeneration of 11-cis-retinal. Mutations in the human RPE65 gene cause Leber's congenital amaurosis (LCA), a severe form of an inherited retinal disorder. Animal models carrying Rpe65 mutations develop early-onset retinal degeneration. In particular, the cones degenerate faster than the rods. To date, gene therapy has been used successfully to treat RPE65-associated retinal disorders. However, gene therapy does not completely prevent progressive retinal degeneration in patients, possibly due to the vulnerability of cones in these patients. In the present study, we tested whether leukemia inhibitory factor (LIF), a trophic factor, protects cones in rd12 mice harboring a nonsense mutation in Rpe65. LIF was administered to rd12 mice by intravitreal microinjection. Apoptosis of retinal cells was analyzed by TUNEL assay. The degeneration of cone cells was evaluated by immunostaining of retinal sections and retinal flat-mounts. Signaling proteins regulated by LIF in the retinal and cultured cells were determined by immunoblotting. Intravitreal administration of LIF activated the STAT3 signaling pathway, thereby inhibiting photoreceptor apoptosis and preserving cones in rd12 mice. Niclosamide (NCL), an inhibitor of STAT3 signaling, effectively blocked STAT3 signaling and autophagy in cultured 661W cells treated with LIF. Co-administration of LIF with NCL to rd12 mice abolished the protective effect of LIF, suggesting that STAT3 signaling and autophagy mediate the protection. LIF is a potent factor that protects cones in rd12 mice. This finding implies that LIF can be used in combination with gene therapy to achieve better therapeutic outcomes for patients with RPE65-associated LCA.
2023-07-17 | Hydrogen peroxide-induced oxidative damage and protective role of peroxiredoxin 6 protein via EGFR/ERK signaling pathway in RPE cells
Introduction Damage to retinal pigment epithelium (RPE) cells caused by oxidative stress is closely related to the pathogenesis of several blinding retinal diseases, such as age-related macular degeneration (AMD), retinitis pigmentosa, and other inherited retinal degenerative conditions. However, the mechanisms of this process are poorly understood. Hence, the goal of this study was to investigate hydrogen peroxide (H 2 O 2 )-induced oxidative damage and protective role of peroxiredoxin 6 (PRDX6) protein via EGFR/ERK signaling pathway in RPE cells. Methods Cells from a human RPE cell line (ARPE-19 cells) were treated with H 2 O 2 , and then cell viability was assessed using the methyl thiazolyl tetrazolium assay. Cell death and reactive oxygen species (ROS) were detected by flow cytometry. The levels of PRDX6, epidermal growth factor receptor (EGFR), P38 mitogen-activated protein kinase (P38MAPK), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) were detected by Western blot assay. PRDX6 and EGFR were also detected via immunofluorescence staining. Results Our results show that H 2 O 2 inhibited cell viability, induced cell death, and increased ROS levels in ARPE-19 cells. It was also found that H 2 O 2 decreased the levels of PRDX6, EGFR, and phosphorylated ERK but increased the levels of phosphorylated P38MAPK and JNK. PRDX6 overexpression was found to attenuate H 2 O 2 -induced inhibition of cell viability and increased cell death and ROS production in ARPE-19 cells. PRDX6 overexpression also increased the expression of EGFR and alleviated the H 2 O 2 -induced decrease in EGFR and phosphorylated ERK. Moreover, inhibition of epidermal growth factor-induced EGFR and ERK signaling in oxidative stress was partially blocked by PRDX6 overexpression. Discussion Our findings indicate that PRDX6 overexpression protects RPE cells from oxidative stress damage caused by decreasing ROS production and partially blocking the inhibition of the EGFR/ERK signaling pathway induced by oxidative stress. Therefore, PRDX6 shows promise as a therapeutic target for the prevention of RPE cell damage caused by oxidative stress associated with retinal diseases.
2021-05-19 | Delivery Systems of Retinoprotective Proteins in the Retina
Retinoprotective proteins play important roles for retinal tissue integrity. They can directly affect the function and the survival of photoreceptors, and/or indirectly target the retinal pigment epithelium (RPE) and endothelial cells that support these tissues. Retinoprotective proteins are used in basic, translational and in clinical studies to prevent and treat human retinal degenerative disorders. In this review, we provide an overview of proteins that protect the retina and focus on pigment epithelium-derived factor (PEDF), and its effects on photoreceptors, RPE cells, and endothelial cells. We also discuss delivery systems such as pharmacologic and genetic administration of proteins to achieve photoreceptor survival and retinal tissue integrity.
2021-01-20 | An In-Silico Study on the Most Effective Growth Factors in Retinal Regeneration Utilizing Tissue Engineering Concepts
Purpose: Considering the significance of retinal disorders and the growing need to employ tissue engineering in this field, in-silico studies can be used to establish a cost-effective method. This in-silico study was performed to find the most effective growth factors contributing to retinal tissue engineering.
Methods: In this study, a regeneration gene database was used. All 21 protein-coding genes participating in retinal regeneration were considered as a protein–protein interaction (PPI) network via the “STRING App” in “Cytoscape 3.7.2” software. The resultant graph possessed 21 nodes as well as 37 edges. Gene ontology (GO) analysis, as well as the centrality analysis, revealed the most effective proteins in retinal regeneration.
Results: According to the biological processes and the role of each protein in different pathways, selecting the correct one is possible through the information that the network provides. Eye development, detection of the visible light, visual perception, photoreceptor cell differentiation, camera-type eye development, eye morphogenesis, and angiogenesis are the major biological processes in retinal regeneration. Based on the GO analysis, SHH, STAT3, FGFR1, OPN4, ITGAV, RAX, and RPE65 are effective in retinal regeneration via the biological processes. In addition, based on the centrality analysis, four proteins have the greatest influence on retinal regeneration: SHH, IGF1, STAT3, and ASCL1.
Conclusion: With the intention of applying the most impressive growth factors in retinal engineering, it seems logical to pay attention to SHH, STAT3, and RPE65. Utilizing these proteins can lead to fabricate high efficiency engineered retina via all aforementioned biological processes.
2019-05-10 | The Role of FGF9 in the Production of Neural Retina and RPE in a Pluripotent Stem Cell Model of Early Human Retinal Development
Purpose
To investigate the role of fibroblast growth factors (FGFs) in the production of neural retina (NR) and retinal pigmented epithelium (RPE) in a human pluripotent stem cell model of early retinal development.
Methods
Human induced pluripotent stem cell (hiPSC) lines from an individual with microphthalmia caused by a functional null mutation (R200Q) in visual system homeobox 2 (VSX2), a transcription factor involved in early NR progenitor cell (NRPC) production, and a normal sibling were differentiated along the retinal and forebrain lineages using an established protocol. Quantitative and global gene expression analyses (microarray and RNAseq) were used to investigate endogenous FGF expression profiles in these cultures over time. Based on these results, mutant and control hiPSC cultures were treated exogenously with selected FGFs and subjected to gene and protein expression analyses to determine their effects on RPE and NR production.
Results
We found that FGF9 and FGF19 were selectively increased in early hiPSC-derived optic vesicles (OVs) when compared to isogenic cultures of hiPSC-derived forebrain neurospheres. Furthermore, these same FGFs were downregulated over time in (R200Q)VSX2 hiPSC-OVs relative to sibling control hiPSC-OVs. Interestingly, long-term supplementation with FGF9, but not FGF19, partially rescued the mutant retinal phenotype of the (R200Q)VSX2 hiPSC-OV model. However, antagonizing FGF9 in wild-type control hiPSCs did not alter OV development.
Conclusions
Our results show that FGF9 acts in concert with VSX2 to promote NR differentiation in hiPSC-OVs and has potential to be used to manipulate early retinogenesis and mitigate ocular defects caused by functional loss of VSX2 activity. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.
Access all drug discovery papers and probability of success in trials forecasts:
Access all drug discovery papers and probability of success in trials forecasts:
Drug Discovery Landscape
22 orphan drug designations for Leber congenital amaurosis, including 1 approved therapy.
22 orphan drug designations for Leber congenital amaurosis, including 1 approved therapy.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
recombinant, replication incompetent adeno-associated virus (AAV) viral vector platform with a serotype 8 capsid with a complementary DNA (cDNA) of the human GUCY2D gene encoding RetGC (AAV8-RK-RetGC) | gene therapies | FDA | — | MeiraGTx UK II Ltd |
adeno-associated virus serotype 8 vector containing single-stranded DNA encoding the unmodified human lebercilin transgene | gene therapies | FDA | Opus Genetics | |
Adeno-associated viral vector serotype 9 (AAV9) containing human RPE65 gene | gene therapies | FDA | — | Cholgene Therapeutics, Inc. |
Human Nuclear Hormone Receptor Subfamily 2 Group E Member 3 (hNR2E3) | gene therapies | FDA | Ocugen, Inc. | |
Adeno-associated viral vector serotype 5 expressing the human Cone-Rod Homeobox gene | gene therapies | EMA | — | Variant |
Adeno-associated virus serotype 5 containing the human NR2E3 gene | gene therapies | EMA | Ocugen Limited | |
Adeno-Associated Virus containing the gene for human Nuclear Hormone Receptor NR2E3 (AAV-hNR2E3) | gene therapies | FDA | Ocugen Inc. | |
a recombinant adeno-associated virus pseudotyped with serotype 5 viral capsid encoding CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats associated protein 9) gene editing constructs | combination | FDA | Editas Medicine | |
Adenovirus associated viral vector serotype 8 containing the human AIPL1 gene | gene therapies | EMA | — | MeiraGTx Belgium |
Brinretigene vesgedparvovec | gene therapies | EMA | FGK Representative Service GmbH | |
antisense oligonucleotide complementary to the exonic splicer enhancer sequence at intron 26 of the centrosomal protein 290 pre-mRNA | oligonucleotides | FDA | Laboratoires Théa | |
Antisense oligonucleotide complementary to the exonic splicer enhancer sequence at intron 26 of the centrosomal protein 290 pre-mRNA | oligonucleotides | EMA | Laboratoires Thea | |
adenovirus associated viral vector serotype 5 containing the human RPE65 gene | gene therapies | FDA | MeiraGTx Limited | |
Adenovirus associated viral vector serotype 5 containing the human RPE65 gene | gene therapies | EMA | MeiraGTx Belgium | |
Adeno-associated viral vector serotype 8 containing the human GUCY2D gene | gene therapies | EMA | — | Fondazione Telethon Ets |
Adenovirus associated viral vector serotype 2 containing the human RPE65 gene [Luxturna] | gene therapies | EMA | Approved | Novartis Europharm Limited |
ADENO-ASSOCIATED VIRUS SEROTYPE 8 VECTOR CONTAINING THE HUMAN AIPL1 GENE | gene therapies | EMA | — | Fondazione Telethon Ets |
9-cis-Retinyl acetate | small molecules | EMA | Granzer Regulatory Consulting & Services GmbH | |
Recombinant adeno-associated virus (serotype 2) (rAAV2) gene transfer agent expressing RPE65 | gene therapies | FDA | — | AmpliPhi Biosciences Corporation |
Recombinant adeno-associated virus retinal pigment epithelium gene vector AAV2-hRPE65v2 | gene therapies | FDA | Spark Therapeutics, Inc. | |
Adenovirus associated viral vector serotype 4 containing the human RPE65 gene | gene therapies | EMA | — | Coave Therapeutics |
rAAV2-CB-hRPE65 | gene therapies | FDA | Applied Genetic Technologies Corp. |
“Terminated” – programs with discontinued clinical trials, or with no updates reported for 5 years after completion or 12 years after the last trial started.
Let's accelerate rare disease drug discovery
Let's accelerate drug discovery
Get access to Explority AI’s forecasts to outperform average preclinical success rates. Whether you’re expanding your R&D pipeline, evaluating a partnership, or simply have a question — we’d love to hear from you.