Stem cell therapy for inherited retinal diseases: a systematic review and meta-analysis.

PURPOSE: Stem cell therapy is a promising therapeutic approach for inherited retinal diseases (IRDs). This study aims to quantitatively examine the effectiveness and safety of stem cell therapy for patients with IRDs, including retinitis pigmentosa and Stargardt disease (STGD). METHODS: We searched PubMed, EMBASE, Web of Science, Cochrane Library databases, and the ClinicalTrials.gov website. The latest retrieval time was August 20, 2023. The primary outcomes were rates and mean difference (MD) of best-corrected visual acuity (BCVA) improvement. Subgroup analyses were conducted according to administration routes and stem cell types. This study was registered with PROSPERO (CRD42022349271). RESULTS: Twenty-one prospective studies, involving 496 eyes (404 RP and 92 STGD) of 382 patients (306 RP and 76 STGD), were included in this study. For RP, the rate of BCVA improvement was 49% and 30% at 6 months and 12 months, respectively, and the BCVA was significantly improved in the operative eyes at 6 months post-treatment (MD = - 0.12 logMAR, 95% CI .17 to - 0.06 logMAR; P < 0.001), while there was no significant difference at 12 months post-treatment (MD = -0.06 logMAR; 95% CI - 0.13 to 0.01 logMAR; P = 0.10). For STGD, the rate of BCVA improvement was 60% and 55% at 6 months and 12 months, respectively, and the BCVA was significantly improved in the operative eyes at 6 months (MD = - 0.14 logMAR, 95% CI - 0.22 to - 0.07 logMAR; P = 0.0002) and 12 months (MD = - 0.17 logMAR, 95% CI - 0.29 to - 0.04 logMAR; P = 0.01). Subgroup analyses showed suprachoroidal space injection of stem cells may be more efficient for RP. Eleven treated-related ocular adverse events from three studies and no related systemic adverse events were reported. CONCLUSIONS: This study suggests stem cell therapy may be effective and safe for patients with RP or STGD. The long-term vision improvement may be limited for RP patients. Suprachoroidal space injection of stem cells may be a promising administration route for RP patients. Limited by the low grade of evidence, large sample size randomized clinical trials are required in the future.

Conditional loss of Ube3d in the retinal pigment epithelium accelerates age-associated alterations in the retina of mice.

Several studies have suggested a correlation between the ubiquitin-proteasome system (UPS) and age-related macular degeneration (AMD), with its phenotypic severity ranging from mild visual impairment to blindness, but the mechanism for UPS dysfunction contributing to disease progression is unclear. In this study, we investigated the role of ubiquitin protein ligase E3D (UBE3D) in aging and degeneration in mouse retina. Conditional knockout of Ube3d in the retinal pigment epithelium (RPE) of mice led to progressive and irregular fundus lesions, attenuation of the retinal vascular system, and age-associated deterioration of rod and cone responses. Simultaneously, RPE-specific Ube3d knockout mice also presented morphological changes similar to the histopathological characteristics of human AMD, in which a defective UPS led to RPE abnormalities such as phagocytosis or degradation of metabolites, the interaction with photoreceptor outer segment, and the transport of nutrients or waste products with choroidal capillaries via Bruch's membrane. Moreover, conditional loss of Ube3d resulted in aberrant molecular characterizations associated with the autophagy-lysosomal pathway, oxidative stress damage, and cell-cycle regulation, which are implicated in AMD pathology. Thus, our findings strengthen and expand the impact of UPS dysfunction on retinal pathophysiology during aging, indicating that genetic Ube3d deficiency in the RPE could lead to the abnormal formation of pigment deposits and secondary fundus alterations. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

An SNX31 variant underlies dominant familial exudative vitreoretinopathy-like pathogenesis.

Familial exudative vitreoretinopathy (FEVR) is a complex hereditary eye disorder characterized by incomplete development of the retinal vasculature, which thereby affects retinal angiogenesis. But the genetic factors contributing to FEVR's development or pathogenesis remain elusive. In a Chinese family with FEVR with 19 members, by using whole-exome sequencing, we identified a candidate disease-causing DNA variant in sorting nexin 31 (SNX31) (c.963delG; p. Trp321Cys), which results in a frameshift mutation. We studied the biochemical mechanism of this mutation and determined that it is deficient in ß1-integrin binding and stability. The SNX31 c.963delG point mutation mouse model (SNX31m/m) was constructed with CRISPR/Cas9 technology. At 2-4 months of age, SNX31m/m mice showed fundus phenotypes similar to FEVR-like changes, including vascular leakage and retinal atrophy. Moreover, we found that VEGF and apoptotic pathways were involved in these ocular phenotypes. Hence, our study extended the FEVR mutation spectrum to include SNX31. These findings expanded our understanding of the molecular pathogenesis of FEVR and may facilitate the development of methods for the diagnosis and prevention of FEVR.

More light components and less light damage on rats' eyes: evidence for the photobiomodulation and spectral opponency.

The blue-light hazard (BLH) has raised concerns with the increasing applications of white light-emitting diodes (LEDs). Many researchers believed that the shorter wavelength or more light components generally resulted in more severe retinal damage. In this study, based on the conventional phosphor-coated white LED, we added azure (484 nm), cyan (511 nm), and red (664 nm) light to fabricate the low-hazard light source. The low-hazard light sources and conventional white LED illuminated 68 Sprague-Dawley (SD) rats for 7 days. Before and after light exposure, we measured the retinal function, thickness of retinal layers, and fundus photographs. The expression levels of autophagy-related proteins and the activities of oxidation-related biochemical indicators were also measured to investigate the mechanisms of damaging or protecting the retina. With the same correlated color temperature (CCT), the low-hazard light source results in significantly less damage on the retinal function and photoreceptors, even if it has two times illuminance and blue-light hazard-weighted irradiance ([Formula: see text]) than conventional white LED. The results illustrated that [Formula: see text] proposed by IEC 62471 could not exactly evaluate the light damage on rats' retinas. We also figured out that more light components could result in less light damage, which provided evidence for the photobiomodulation (PBM) and spectral opponency on light damage.

Expression profiling suggests the involvement of hormone-related, metabolic, and Wnt signaling pathways in pterygium progression.

Background: Pterygium is an ocular surface disease that can cause visual impairment if it progressively invades the cornea. Although many pieces of research showed ultraviolet radiation is a trigger of pterygium pathological progress, the underlying mechanism in pterygium remains indistinct. Methods: In this study, we used microarray to evaluate the changes of transcripts between primary pterygium and adjacent normal conjunctiva samples in China. Then, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses. Moreover, we constructed protein-protein interaction (PPI) and miRNA-mRNA regulatory networks to predict possible regulatory relationships. We next performed gene set enrichment analysis (GSEA) to explore the similarities and differences of transcripts between Asian studies from the Gene Expression Omnibus database. Furthermore, we took the intersection of differentially expressed genes (DEGs) with other data and identified hub genes of the development of pterygium. Finally, we utilized real-time quantitative PCR to verify the expression levels of candidate genes. Results: A total of 49 DEGs were identified. The enrichment analyses of DEGs showed that pathways such as the Wnt-signaling pathway and metabolism-related pathways were upregulated, while pathways such as hormone-related and transcription factor-associated pathways were downregulated. The PPI and miRNA-mRNA regulatory networks provide ideas for future research directions. The GSEA of selecting Asian data revealed that epithelial-mesenchymal transition and myogenesis existed in the pathology of pterygium in the Asian group. Furthermore, five gene sets (interferon-gamma response, Wnt beta-catenin signaling, oxidative phosphorylation, DNA repair, and MYC targets v2) were found only in our Chinese datasets. After taking an intersection between selecting datasets, we identified two upregulated (SPP1 and MYH11) and five downregulated (ATF3, FOS, EGR1, FOSB, and NR4A2) hub genes. We finally chose night genes to verify their expression levels, including the other two genes (SFRP2 and SFRP4) involved in Wnt signaling; Their expression levels were significantly different between pterygium and conjunctiva. Conclusions: We consider hormone-related, metabolic, and Wnt signaling pathways may be important in the pathology of pterygium development. Nine candidate genes we identified deserve further study and can be potential therapeutic targets.

UBE3D Is Involved in Blue Light-Induced Retinal Damage by Regulating Double-Strand Break Repair.

Purpose: Age-related macular degeneration (AMD) is currently the leading cause of blindness worldwide. Previously, we identified ubiquitin-protein ligase E3D (UBE3D) as an AMD-associated protein for East Asian populations, and here we further demonstrate that UBE3D could be associated with DNA damage response. Methods: The established I-SceI-inducible GFP reporter system was used to explore the effect of UBE3D on homologous recombination. Immunoprecipitation-mass spectrometry (MS) was used to explore potential UBE3D-interacting proteins and validated with coimmunoprecipitation assays and the pulldown assays. Micrococcal nuclease (MNase) assays were used to investigate the function of UBE3D on heterochromatin de-condensation upon DNA damage. An aged mouse model of blue light-induced eye damage was constructed, and electroretinography (ERG) and optical coherence tomography (OCT) were performed to compare the differences between wild-type and UBE3D+/- mice. Results: First, we show that GFP-UBE3D is recruited to damage sites by PCNA, through a PCNA-interacting protein (PIP) box. Furthermore, UBE3D interacts with KAP1 via R377R378 and oxidation of the AMD-associated V379M mutation abolishes KAP1-UBE3D binding. By MNase assays, UBE3D depletion reduces the chromatin relaxation levels upon DNA damage. In addition, UBE3D depletion renders less KAP1 recruitment. Compared with wild type, blue light induces less damage in UBE3D+/- mice as measured by ERG and OCT, consistent with our biochemical results. Conclusions: Hence, we propose that one potential mechanism that UBE3D-V379M contributes to AMD pathogenesis might be via defective DNA damage repair linked with oxidative stress and our results offered a potential direction for the treatment of AMD.

Ocular phenotype and genetical analysis in patients with retinopathy of prematurity.

BACKGROUND: Retinopathy of prematurity (ROP) is a multifactorial retinal disease, involving both environmental and genetic factors; The purpose of this study is to evaluate the clinical presentations and genetic variants in Chinese patients with ROP. METHODS: A total of 36 patients diagnosed with ROP were enrolled in this study, their medical and ophthalmic histories were obtained, and comprehensive clinical examinations were performed. Genomic DNA was isolated from peripheral blood of ROP patients, polymerase chain reaction and direct sequencing of the associated pathogenic genes (FZD4, TSPAN12, and NDP) were performed. RESULTS: All patients exhibited the clinical manifestations of ROP. No mutations were detected in the TSPAN12 and NDP genes in all patients; Interestingly, three novel missense mutations were identified in the FZD4 gene (p.A2P, p.L79M, and p.Y378C) in four patients, for a detection rate of 11.1% (4/36). CONCLUSIONS: This study expands the genotypic spectrum of FZD4 gene in ROP patients, and our findings underscore the importance of obtaining molecular analyses and comprehensive health screening for this retinal disease.

Ocular Features and Mutation Spectrum of Patients With Familial Exudative Vitreoretinopathy.

Purpose: To investigate the clinical findings in Chinese patients diagnosed with familial exudative vitreoretinopathy (FEVR) and carrying pathogenic mutations. Methods: One hundred twenty unrelated patients with FEVR were enrolled in this study. Genomic DNA and ophthalmic examinations were collected from all the patients and their available relatives. Targeted next-generation sequencing was performed to detect mutations. In silico programs were used to evaluate the pathogenicity of all the mutations. Results: Eighty identified mutations were found in 81 unrelated patients (31/81 in LRP5, 25/81 in FZD4, 12/81 in TSPAN12, 8/81 in NDP, 4/81 in KIF11, and 1/81 in ZNF408). Among those mutations, 53 were novel (23/35 in LRP5, 15/21 in FZD4, 8/11 in TSPAN12, 3/8 in NDP, 3/4 in KIF11, 1/1 in ZNF408). Patients with LRP5, FZD4, TSPAN12, or NDP mutations were mainly classified into stage 4 and stage 5 and one-half of patients with KIF11 mutations were in stage 4. In addition, all the patients in NDP group were found to have bilateral symmetry in FEVR stage. Conclusions: Our results present profound phenotypic variability and a wide mutation spectrum of FEVR in the Chinese population, which could be useful for a precise and comprehensive genetic diagnosis for patients with FEVR in the future.

RNA-Seq Analysis for Exploring the Pathogenesis of Retinitis Pigmentosa in P23H Knock-In Mice.

INTRODUCTION: Mechanisms contributing to the progression of autosomal dominant retinitis pigmentosa (adRP) due to the P23H rhodopsin mutation are complex and diverse. Previous studies showed that mechanisms like endoplasmic reticulum (ER) stress, pyroptosis, and oxidative stress were involved in the pathogenesis of the disease. However, the roles and relationships of different mechanisms are not precisely known. In this study, we aimed to evaluate certain mechanisms and find novel genes involved in P23H-related adRP. METHODS: Total RNA extracted at postnatal day (PN) 14, PN21, and PN35 was used for RNA sequencing. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses were conducted for RNA-seq data. Additionally, data from the clustered regularly interspaced short palindromic repeats (CRISPR) screening library and the RNA-seq data of several mechanisms were used for generating custom gene sets for gene set enrichment analysis (GSEA). Next, we obtained the intersection of the aforementioned gene sets and our RNA-seq data to identify candidate genes, which were verified using real-time quantitative PCR (qPCR). RESULTS: Functional enrichment analyses were consistent with disease phenotypes. All time points observed pyroptosis. In the results of GSEA, ER stress, pyroptosis, and oxidative stress were observed at PN14. ER stress and pyroptosis were shown on PN35. A total of 22 candidate genes were identified. The expression levels of selected genes verified by qPCR were concordant with the RNA-seq data. CONCLUSIONS: In our study, we conclude that pyroptosis and ER stress might play a central role in RP progression. We also identified differentially expressed gene clusters related to ER stress and pyroptosis, which deserve further study. These findings provide a novel perspective for the investigation of P23H-related adRP.

The critical role of m6A methylation in the pathogenesis of Graves' ophthalmopathy.

PURPOSE: To investigate the role of N6-methyladenosine (m6A) RNA modification in the pathogenesis of Graves' ophthalmopathy (GO). METHODS: Surgically excised extraocular muscles from 7 patients with GO and 5 subjects without GO were used. The global m6A levels in the specimens were determined using an m6A RNA methylation quantification kit. RNA sequencing (RNA-seq) was used to analyze the molecules involved in the regulation of m6A RNA methylation and the differential expression of mRNAs between the two groups (4 eyes, respectively). The expression of m6A RNA modification genes was evaluated by real-time PCR. The functional implications of the gene alterations between the GO and control specimens were determined by Gene Ontology analysis. RESULTS: The m6A level was significantly increased in the specimens of GO patients compared to the control specimens (P < 0.05). The expression of m6A methylation regulators, such as WT1 associated protein (WTAP), alkylation repair homolog protein 5 (ALKBH5), E74 like ETS transcription factor 3 (ELF3), YTH N6-methyladenosine RNA binding protein 2 (YTHDF2), YTHDF3 and YTH domain containing 2 (YTHDC2), was significantly upregulated (P < 0.05). Gene Ontology enrichment analysis showed that the most highly upregulated genes and biological pathways were related to the immune response and inflammatory processes such as lymphocyte activation, leukocyte differentiation, cytokine production and cytokine-mediated signaling pathways. CONCLUSIONS: Our results suggest that m6A methylation may play a critical role in the pathogenesis of GO and that targeting genes that regulate m6A methylation may provide a new therapeutic approach for GO.

Associations of systemic, serum lipid and lipoprotein metabolic pathway gene variations with polypoidal choroidal vasculopathy in China.

BACKGROUND: To investigate the association of systemic, serum lipids and genetic variants in the high-density lipoprotein (HDL) metabolic pathway with polypoidal choroidal vasculopathy (PCV) in China. METHODS: The case-control study was included 150 controls and 66 cases with PCV. Serum levels of total cholesterol (TC), low-density lipoprotein (LDL), HDL, triglycerides (TG), apolipoprotein A1 (APOA1), apolipoprotein B (APOB) together with systemic risk factors including gender, hyperlipidemia, diabetes mellitus (DM), hypertension, coronary artery disease (CAD) and asthma were identified. All subjects were genotyped for four single nucleotide polymorphisms (SNPs) from three genes in the HDL metabolic pathway: rs10468017 of hepatic lipase (LIPC), rs12678919 of lipoprotein lipase (LPL), rs3764261 and rs173539 of cholesterol ester transfer protein (CETP) with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Student's t-tests, chi-square tests, anova and logistic regression were used to evaluate associations. RESULTS: Hyperlipidemia was a risk factor (odds ratio (OR) = 1.19, P = 0.001) for PCV. HDL, LDL and APOB levels were associated with PCV (OR = 0.001, P = 0.004; OR = 0.099, P = 0.010; OR = 0.839, P = 0.018). Higher level of TC was potently associated with increased risk of PCV (OR = 109.8, P = 0.000). LIPC rs10468017 was a risk factor for PCV (OR = 11.68, P = 0.000). CETP rs3764261 conferred a decreased risk for PCV (OR = 0.08, P = 0.000). No associations of LPL rs12678919 or CETP rs173539 with PCV were found. Mean level of HDL increased with T allele of the CETP gene (p = 0.026): 1.24 mmol/L (±0.31) for the GG genotype and 1.66 mmol/L (±0.54) for the TT genotype. Additionally, T allele was associated with the following increase in APOA1: 136.78 mg/dl (±20.53) for the CC genotype and 149.57 mg/dl (±22.67) for the TT genotype of LIPC and 137.91 mg/dl (±20.36) for the GG genotype and 162.67 mg/dl (±22.50) for the TT genotype of CETP gene. CONCLUSION: Our study suggested that the significant association was found between hyperlipidemia, the serum levels of TC, HDL, LDL and APOB and PCV. The result of present study also showed that the association of LIPC rs10468017 and CETP rs3764261 with PCV.