Selective microRNA expression of exosomes from retinal pigment epithelial cells by oxidative stress.

The function of exosomal miRNAs (miRs) in retinal degeneration is largely unclear. We were aimed to investigate the functions of exosomes as well as their miRs derived from retinal pigment epithelial (RPE) cells following exposure to oxidative stress (OS). After the OS by lipopolysaccharide and rotenone on RPE cells, interleukin-1 beta (IL-1ß), Interleukin-6 (IL-6), Tumor Necrosis Factor-alpha (TNF-α) were upregulated, along with the decreased mitochondrial membrane potential and upregulated oxidative damage marker 8-OH-dG in RPE cells. RPE-derived exosomes were then isolated, identified, injected into the subretinal space in mice. After subretinal injection, RPE-exosomes after OS not only induced higher ROS level and apoptotic retinal cells, but also elevated IL-1ß, IL-6 alongside TNF-α expressions among retina/RPE/choroidal complex. Next, miRs inside the exosomes were sequenced by the next generation sequencing (NGS) technology. NGS revealed that certain miRs were abundant in exosomes, while others were selectively kept by RPE cells. Further, downregulated miRs, like miR-125b-5p, miR-125a-5p, alongside miR-128-3p, and upregulated miR, such as miR-7-5p were validated byRT-qPCR. Finally, Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to find the possible target genes of those selective exosomal miRs. Our results proved that the RPE-derived exosomes after OS selectively express certain miRs, providing novel insights into the pathogenesis of age-related macular degeneration (AMD) in future.

OCTA-500: A retinal dataset for optical coherence tomography angiography study.

Optical coherence tomography angiography (OCTA) is a novel imaging modality that has been widely utilized in ophthalmology and neuroscience studies to observe retinal vessels and microvascular systems. However, publicly available OCTA datasets remain scarce. In this paper, we introduce the largest and most comprehensive OCTA dataset dubbed OCTA-500, which contains OCTA imaging under two fields of view (FOVs) from 500 subjects. The dataset provides rich images and annotations including two modalities (OCT/OCTA volumes), six types of projections, four types of text labels (age/gender/eye/disease) and seven types of segmentation labels (large vessel/capillary/artery/vein/2D FAZ/3D FAZ/retinal layers). Then, we propose a multi-object segmentation task called CAVF, which integrates capillary segmentation, artery segmentation, vein segmentation, and FAZ segmentation under a unified framework. In addition, we optimize the 3D-to-2D image projection network (IPN) to IPN-V2 to serve as one of the segmentation baselines. Experimental results demonstrate that IPN-V2 achieves an about 10% mIoU improvement over IPN on CAVF task. Finally, we further study the impact of several dataset characteristics: the training set size, the model input (OCT/OCTA, 3D volume/2D projection), the baseline networks, and the diseases. The dataset and code are publicly available at: https://ieee-dataport.org/open-access/octa-500.

Human lens epithelial-secreted exosomes attenuate ocular angiogenesis via inhibiting microglial activation.

The lens is an avascular tissue, where epithelial cells (LECs) are the primary living cells. The role of LECs-derived exosomes (LEC-exos) is largely unknown. In our study, we determined the anti-angiogenic role of LEC-exos, manifested as regressed retinal neovascularization (NV) using the oxygen-induced retinopathy (OIR), and reduced choroidal NV size and pathological vascular leakage using the laser-induced choroidal neovascularization (laser-induced CNV). Furthermore, the activation and accumulation of microglia were also restricted by LEC-exos. Based on Luminex multiplex assays, the expressions of chemokines such as SCYB16/CXCL16, MCP-1/CCL2, I-TAC/CXCL11, and MIP 3beta/CCL19 were decreased after treatment with LEC-exos. Transwell assays showed that LEC-exos restricted the migration of the mouse microglia cell line (BV2 cells). After incubation with LEC-exos-treated BV2 cells, human umbilical vein endothelial cells (hUVECs) were collected for further evaluation using tube formation, Transwell assays, and 5-ethynyl-2'-deoxyuridine (EDU) assays. Using in vitro experiments, the pro-angiogenic effect of microglia was restricted by LEC-exos. Hence, it was investigated that LEC-exos attenuated ocular NV, which might attribute to the inhibition of microglial activation and accumulation.

Prevalence and causes of blindness and distance visual impairment in Chinese adult population in 2022 during the COVID-19 pandemic: a cross-sectional study.

This cross-sectional study aims to investigate the prevalence and causes of visual impairment (VI) and blindness in Jiangsu Province, China in 2022 during the COVID-19 pandemic. Participants (n = 13,208, aged 18-93) underwent comprehensive ocular examinations. The prevalence and causes of binocular VI (presenting visual acuity [VA] ≥ 20/400 and < 20/63 in the better eye) and blindness (presenting VA < 20/400 in the better eye) were assessed according to the World Health Organization (WHO) criteria. The estimation of refractive error prevalence was conducted using the following classification: myopia ≤ - 0.50 diopters (D), high myopia ≤ - 6.00 D, hyperopia ≥ 0.50 D, and anisometropia ≥ 1.00 D. The overall prevalence of binocular VI and blindness was 21.04% (95% confidence interval [CI] 20.35-21.74%) and 0.47% (95% CI 0.37-0.60%). The highest prevalence of binocular VI was in the population aged 18-24 years old (46.29%, [95% CI 44.30-48.28%]), those with education at university and above (43.47%, [95% CI 41.93-45.02%]), students (54.96%, [95% CI 52.73-57.17%]). Uncorrected refractive error (URE) was the leading cause of presenting binocular VI (93.40%) and blindness (50.79%). The prevalence of myopia was 54.75% (95% CI 53.90-55.60%). Actions are needed to control URE and myopia within the adult Chinese population, with a particular emphasis on the younger, well-educated demographic.

m6A-Mediated Upregulation of Imprinted in Prader-Willi Syndrome Induces Aberrant Apical-Basal Polarization and Oxidative Damage in RPE Cells.

Purpose: To reveal the clinical significance, pathological involvement and molecular mechanism of imprinted in Prader-Willi syndrome (IPW) in RPE anomalies that contribute to AMD. Methods: IPW expression under pathological conditions were detected by microarrays and qPCR assays. In vitro cultured fetal RPE cells were used to study the pathogenicity induced by IPW overexpression and to analyze its upstream and downstream regulatory networks. Results: We showed that IPW is upregulated in the macular RPE-choroid tissue of dry AMD patients and in fetal RPE cells under oxidative stress, inflammation and dedifferentiation. IPW overexpression in fetal RPE cells induced aberrant apical-basal polarization as shown by dysregulated polarized markers, disrupted tight and adherens junctions, and inhibited phagocytosis. IPW upregulation was also associated with RPE oxidative damages, as demonstrated by intracellular accumulation of reactive oxygen species, reduced cell proliferation, and accelerated cell apoptosis. Mechanically, N6-methyladenosine level of the IPW transcript regulated its stability with YTHDC1 as the reader. IPW mediated RPE features by suppressing MEG3 expression to sequester its inhibition on the AKT serine-threonine kinase (AKT)/mammalian target of rapamycin (mTOR) pathway. We also noticed that the mTOR inhibitor rapamycin suppresses the AKT/mTOR pathway to alleviate the IPW-induced RPE anomalies. Conclusions: We revealed that IPW overexpression in RPE induces aberrant apical-basal polarization and oxidative damages, thus contributing to AMD progression. We also annotated the upstream and downstream regulatory networks of IPW in RPE. Our findings shed new light on the molecular mechanisms of RPE dysfunctions, and indicate that IPW blockers may be a promising option to treat RPE abnormalities in AMD.

Lactylation-driven FTO targets CDK2 to aggravate microvascular anomalies in diabetic retinopathy.

Diabetic retinopathy (DR) is a leading cause of irreversible vision loss in working-age populations. Fat mass and obesity-associated protein (FTO) is an N6-methyladenosine (m6A) demethylase that demethylates RNAs involved in energy homeostasis, though its influence on DR is not well studied. Herein, we detected elevated FTO expression in vitreous fibrovascular membranes of patients with proliferative DR. FTO promoted cell cycle progression and tip cell formation of endothelial cells (ECs) to facilitate angiogenesis in vitro, in mice, and in zebrafish. FTO also regulated EC-pericyte crosstalk to trigger diabetic microvascular leakage, and mediated EC-microglia interactions to induce retinal inflammation and neurodegeneration in vivo and in vitro. Mechanistically, FTO affected EC features via modulating CDK2 mRNA stability in an m6A-YTHDF2-dependent manner. FTO up-regulation under diabetic conditions was driven by lactate-mediated histone lactylation. FB23-2, an inhibitor to FTO's m6A demethylase activity, suppressed angiogenic phenotypes in vitro. To allow for systemic administration, we developed a nanoplatform encapsulating FB23-2 and confirmed its targeting and therapeutic efficiency in mice. Collectively, our study demonstrates that FTO is important for EC function and retinal homeostasis in DR, and warrants further investigation as a therapeutic target for DR patients.

Angiogenic and Fibrogenic Dual-effect of Gremlin1 on Proliferative Diabetic Retinopathy.

Ocular angiogenic diseases, such as proliferative diabetic retinopathy (PDR), are often characterized by pathological new vessels and fibrosis formation. Anti-vascular endothelial growth factor (VEGF) therapy, despite of its efficiency to inhibit new vessels, has limitations, including drug resistance and retinal fibrosis. Here, we identified that Gremlin1, a novel angiogenesis and fibrosis inducer, was secreted from Müller glial cells, and its expression increased in the vitreous fluid from patients with PDR. Mechanistically, Gremlin1 triggered angiogenesis by promoting endothelial-mesenchymal transition via the EGFR/RhoA/ROCK pathway. In addition, Gremlin1 activated microglia to present profibrotic and fibrogenic properties. Further, anti-Gremlin1 antibody inhibited ocular angiogenesis and microglia fibrosis in mouse models. Collectively, Gremlin1 could be a potential therapeutic target in the treatment of ocular angiogenic diseases.

Initial screening for occult congenital ectopia lentis based on ocular biological parameters in preschool children.

BACKGROUND: This study aimed to identify an initial screening tool for congenital ectopia lentis (CEL) by comparing ocular biological parameters in children with myopia. METHODS: A retrospective case-control study was conducted at one tertiary referral centre, from October 2020 to June 2022. Axial length (AL), corneal curvature (CC), refractive astigmatism (RA), corneal astigmatism (CA), internal astigmatism (IA), the difference between the axis of RA and CA [AXIS(RA-CA)], white-to-white corneal diameter (WTW), and axial length-corneal radius ratio (AL/CR) were compared in 28 eyes of CEL patients, and 60 eyes of myopic patients matched for age and refraction. The spherical equivalent of each eye was < -3.00 D. Area under the curve (AUC) of the receiver operating characteristic curves were calculated. RESULTS: The differences in RA, AL, mean keratometry (Kmed), maximum keratometry (Kmax), minimum keratometry (Kmin), CA, IA, AXIS(RA-CA), WTW, and AL/CR between the CEL and myopic groups were statistically significant (p < 0.05; p < 0.001; p < 0.001; p < 0.001; p < 0.001; p < 0.05; p < 0.001; p < 0.001; p < 0.001; p < 0.001, respectively). In logistic regression analysis RA, IA, AXIS(RA-CA), and AL/CR were significantly associated with CEL (p < 0.05). AUCs for RA, IA, AXIS(RA-CA), and AL/CR were 0.694, 0.853, 0.814, and 0.960, respectively. AUCs for AL/CR in SE< -6.00 D subgroup was 0.970, and 0.990 in -6.00 D ≤ SE < -3.00 D group. An AL/CR < 3.024 was the optimal cut-off point differentiating the CEL and control groups (sensitivity, 92.9%; specificity, 88.30%). CONCLUSIONS: A smaller AL/CR could identify CEL in children with myopia. An AL/CR cut-off value of 3.024 may be the most sensitive and specific parameter for the differential diagnosis of CEL in patients with mild to high myopia.

Prediction of SMILE surgical cutting formula based on back propagation neural network.

AIM: To predict cutting formula of small incision lenticule extraction (SMILE) surgery and assist clinicians in identifying candidates by deep learning of back propagation (BP) neural network. METHODS: A prediction program was developed by a BP neural network. There were 13 188 pieces of data selected as training validation. Another 840 eye samples from 425 patients were recruited for reverse verification of training results. Precision of prediction by BP neural network and lenticule thickness error between machine learning and the actual lenticule thickness in the patient data were measured. RESULTS: After training 2313 epochs, the predictive SMILE cutting formula BP neural network models performed best. The values of mean squared error and gradient are 0.248 and 4.23, respectively. The scatterplot with linear regression analysis showed that the regression coefficient in all samples is 0.99994. The final error accuracy of the BP neural network is -0.003791±0.4221102 µm. CONCLUSION: With the help of the BP neural network, the program can calculate the lenticule thickness and residual stromal thickness of SMILE surgery accurately. Combined with corneal parameters and refraction of patients, the program can intelligently and conveniently integrate medical information to identify candidates for SMILE surgery.

Lens epithelial cell-derived exosome inhibits angiogenesis in ocular pathological neovascularization through its delivery of miR-146a-5p.

Abnormal ocular neovascularization, a major pathology of eye diseases, leads to severe visual loss. The role of lens epithelial cell (LEC)-derived exosomes (Lec-exo) is largely unknown. Thus, we aimed to investigate whether Lec-exo can inhibit abnormal ocular neovascularization and explore the possible mechanisms. In our study, we proved the first evidence that exosomes derived from LECs attenuated angiogenesis in both oxygen-induced retinopathy and laser-induced choroidal neovascularization mice models. Further in vitro experiments proved that Lec-exo inhibited proliferation, migration, and tube formation capability of human umbilical vein endothelial cells in high glucose condition. Further high-throughput miRNAs sequencing analysis detected that miR-146a-5p was enriched in Lec-exo. Mechanistically, exosomal miR-146a-5p was delivered to endothelial cells and bound to the NRAS coding sequence, which subsequently inactivated AKT/ERK signaling pathway. We successfully elucidated the function of Lec-exo in inhibiting abnormal ocular neovascularization, which may offer a promising strategy for treatment of abnormal ocular neovascularization.

ALKBH5 causes retinal pigment epithelium anomalies and choroidal neovascularization in age-related macular degeneration via the AKT/mTOR pathway.

Retinal pigment epithelium (RPE) dysfunction and choroidal neovascularization (CNV) are predominant features of age-related macular degeneration (AMD), with an unclear mechanism. Herein, we show that RNA demethylase α-ketoglutarate-dependent dioxygenase alkB homolog 5 (ALKBH5) is up-regulated in AMD. In RPE cells, ALKBH5 overexpression associates with depolarization, oxidative stress, disturbed autophagy, irregular lipid homeostasis, and elevated VEGF-A secretion, which subsequently promotes proliferation, migration, and tube formation of vascular endothelial cells. Consistently, ALKBH5 overexpression in mice RPE correlates with various pathological phenotypes, including visual impairments, RPE anomalies, choroidal neovascularization (CNV), and interrupted retinal homeostasis. Mechanistically, ALKBH5 regulates retinal features through its demethylation activity. It targets PIK3C2B and regulates the AKT/mTOR signaling pathway with YTHDF2 as the N6-methyladenosine reader. IOX1, an ALKBH5 inhibitor, suppresses hypoxia-induced RPE dysfunction and CNV progression. Collectively, we demonstrate that ALKBH5 induces RPE dysfunction and CNV progression in AMD via PIK3C2B-mediated activation of the AKT/mTOR pathway. Pharmacological inhibitors of ALKBH5, like IOX1, are promising therapeutic options for AMD.

The Exosome-Transmitted lncRNA LOC100132249 Induces Endothelial Dysfunction in Diabetic Retinopathy.

Diabetic retinopathy (DR), one of the most common microangiopathic complications in diabetes, causes severe visual damage among working-age populations. Retinal vascular endothelial cells, the key cell type in DR pathogenesis, are responsible for abnormal retinal angiogenesis in advanced stages of DR. The roles of exosomes in DR have been largely unknown. In this study, we report the first evidence that exosomes derived from the vitreous humor of patients with proliferative DR (PDR-exo) promote proliferation, migration, and tube formation of human retinal vascular endothelial cells (HRVECs). We identified long noncoding RNA (lncRNA) LOC100132249 enrichment in PDR-exo via high-throughput sequencing. This lncRNA, also mainly derived from HRVECs, promoted angiogenesis both in vitro and in vivo. Mechanistically, LOC100132249 acted as a competing endogenous sponge of miRNA-199a-5p (miR-199a-5p), thus regulating the endothelial-mesenchymal transition promoter SNAI1 via activation of the Wnt/ß-catenin pathway and ultimately resulting in endothelial dysfunction. In conclusion, our findings underscored the pathogenic role of endothelial-derived exosomes via the LOC100132249/miR-199a-5p/SNAI1 axis in DR angiogenesis and may shed light on new therapeutic strategies for future treatment of DR. ARTICLE HIGHLIGHTS: This study provides the first evidence that exosomes derived from vitreous humor from patients with proliferative diabetic retinopathy participate in angiogenesis. The findings demonstrate an unreported long noncoding RNA (lncRNA), LOC100132249, by exosomal sequencing of vitreous humor. The newly found lncRNA LOC100132249, mainly derived from endothelial cells, promotes angiogenesis via an miRNA-199a-5p/SNAI1/Wnt/ß-catenin axis in a pro-endothelial-mesenchymal transition manner.

Circular RNA expression and the competitive endogenous RNA network in pathological, age-related macular degeneration events: A cross-platform normalization study.

Age-related macular degeneration (AMD) causes irreversible blindness in people aged over 50 worldwide. The dysfunction of the retinal pigment epithelium is the primary cause of atrophic AMD. In the current study, we used the ComBat and Training Distribution Matching method to integrate data obtained from the Gene Expression Omnibus database. We analyzed the integrated sequencing data by the Gene Set Enrichment Analysis. Peroxisome and tumor necrosis factor-α (TNF-α) signaling and nuclear factor kappa B (NF-κB) were among the top 10 pathways, and thus we selected them to construct AMD cell models to identify differentially expressed circular RNAs (circRNAs). We then constructed a competing endogenous RNA network, which is related to differentially expressed circRNAs. This network included seven circRNAs, 15 microRNAs, and 82 mRNAs. The Kyoto Encyclopedia of Genes and Genomes analysis of mRNAs in this network showed that the hypoxia-inducible factor-1 (HIF-1) signaling pathway was a common downstream event. The results of the current study may provide insights into the pathological processes of atrophic AMD.

Epigenetic regulation in the commitment of progenitor cells during retinal development and regeneration.

Retinal development is initiated by multipotent retinal progenitor cells, which undergo several rounds of cell divisions and subsequently terminal differentiation. Retinal regeneration is usually considered as the recapitulation of retinal development, which share common mechanisms underlying the cell cycle re-entry of adult retinal stem cells and the differentiation of retinal neurons. However, how proliferative retinal progenitor cells perform a precise transition to postmitotic retinal cell types during the process of development and regeneration remains elusive. It is proposed that both the intrinsic and extrinsic programming are involved in the transcriptional regulation of the spatio-temporal fate commitment. Epigenetic modifications and the regulatory mechanisms at both DNA and chromatin levels are also postulated to play an important role in the timing of differentiation of specific retinal cells. In the present review, we have summarized recent knowledge of epigenetic regulation that underlies the commitment of retinal progenitor cells in the settings of retinal development and regeneration.

A novel model of subretinal edema induced by DL-alpha aminoadipic acid.

In this study we described a new model of subretinal edema induced by single intraocular injection of DL-alpha-aminoadipic acid (DLAAA) that can be employed to study the mechanism of retinal edema and test the efficacy or potential toxicity of treatments. The progression of subretinal edema was evaluated by fundus photography, fluorescein angiography and optical coherence tomography for up to 4 weeks following DLAAA injection. The VEGF, IL-6, TNF-α, Occludin, ZO-1, AQP4, Kir4.1, GFAP and GS levels were examined in DLAAA models by immunostaining, immumohistochemical staining and Western blot. Additionally, bulk RNA-seq was used to detect the mechanism involved in DLAAA-induced retinal Müller cellular injuries. In vivo and vitro assays were further conducted to confirm the sequencing results. Subretinal edema was successfully induced by DLAAA in New Zealand White rabbits (1.29 mg/eye) and C57BL/6 mice (50 or 100 µg/eye). Our results demonstrated that the disruption of blood-retinal-barrier, including vascular hyperpermeability, inflammation, and Müller cell dysfunction of fluid clearance, was involved in subretinal edema formation in the model. Bulk RNA-seq and in vitro studies indicated the activation of p38 MAPK signaling pathway in DLAAA models. This DLAAA-induced subretinal edema model can be used for mechanistic studies or drug screening.

JP1, a polypeptide specifically targeting integrin αVß3, ameliorates choroidal neovascularization and diabetic retinopathy in mice.

Anti-vascular endothelial growth factor (VEGF) drugs have revolutionized the treatment of neovascular eye diseases, but responses are incomplete in some patients. Recent evidence shows that integrins are involved in the pathogenesis of neovascular age-related macular degeneration and diabetic retinopathy. JP1, derived from an optimized seven-amino-acid fragment of JWA protein, is a polypeptide specifically targeting integrin αVß3. In this study we evaluated the efficacy of JP1 on laser-induced choroidal neovascularization (CNV) and retinal vascular leakage. CNV mice received a single intravitreal (IVT) injection of JP1 (10, 20, 40 µg) or ranibizumab (RBZ, 10 µg). We showed that JP1 injection dose-dependently inhibited laser-induced CNV; the effect of RBZ was comparable to that of 20 µg JP1; a combined IVT injection of JP1 (20 µg) and RBZ (5 µg) exerted a synergistic effect on CNV. In the 3rd month after streptozotocin injection, diabetic mice receiving IVT injection of JP1 (40 µg) or RBZ (10 µg) once a week for 4 weeks showed significantly suppressed retinal vascular leakage. In both in vivo and in vitro experiments, JP1 counteracted oxidative stress and inflammation via inhibiting ROS/NF-κB signaling in microglial cells, and angiogenesis via modulating MEK1/2-SP1-integrin αVß3 and TRIM25-SP1-MMP2 axes in vascular endothelial cells. In addition, intraperitoneal injection of JP1 (1, 5 or 10 mg) once every other day for 3 times also dose-dependently inhibited CNV. After intraperitoneal injection of FITC-labeled JP1 (FITC-JP1) or FITC in laser-induced CNV mice, the fluorescence intensity in the CNV lesion was markedly increased in FITC-JP1 group, compared with that in FITC group, confirming that JP1 could penetrate the blood-retinal barrier to target CNV lesion. We conclude that JP1 can be used to design novel CNV-targeting therapeutic agents that may replace current invasive intraocular injections.

Safety of Fixed-Combination Bimatoprost 0.03%/Timolol 0.5% Ophthalmic Solution at 6 Months in Chinese Patients with Open-Angle Glaucoma or Ocular Hypertension.

INTRODUCTION: Fixed-combination bimatoprost 0.03%/timolol 0.5% ophthalmic solution (FCBT; Ganfort®, Allergan, an AbbVie company) effectively reduces intraocular pressure (IOP) via complementary mechanisms of action of the agents, but long-term (> 12 weeks) safety evaluations of FCBT remain limited. FCBT safety is evaluated herein, with particular focus on hyperemia and eyelash growth, at 24 weeks in Chinese patients with open-angle glaucoma (OAG) or ocular hypertension (OHT). METHODS: In this multicenter, open-label, noncomparative, phase 4 study conducted in China, patients diagnosed with OAG or OHT having insufficient response to ß-blocker- or prostaglandin analogue/prostamide (PGA)-based IOP-lowering monotherapy in one or both eyes were switched from their current IOP-lowering treatment to FCBT (one drop per eye every evening) without prior washout. Assessment visits were scheduled at baseline and weeks 4, 12, and 24 (or study exit). The primary outcome measure was adverse event (AE) incidence through 24 weeks. RESULTS: Of 725 patients enrolled, 632 (87.2%) completed the study; 93 (12.8%) patients discontinued, including 29 (4.0%) due to AEs. Of 1326 FCBT-treated eyes (total), 594 (44.8%) experienced ≥ 1 ocular treatment-related AE during the study. Conjunctival hyperemia (the most common AE overall) and eyelash growth were reported in 269 (20.3%) and 54 (4.1%) FCBT-treated eyes, respectively. The incidence of other known PGA-related AEs (including blepharal pigmentation and erythema of eyelid) was < 10% each. Most conjunctival hyperemia reports were mild in severity (214/259; 82.6%) and only 1/259 (0.4%) was severe. Similarly, most cases of eyelash growth were mild (46/52; 88.5%); none were severe. One (< 0.1%) FCBT-treated eye had a serious ocular AE (OAG) considered FCBT-related. CONCLUSIONS: The frequency and severity of FCBT-related AEs, including conjunctival hyperemia and eyelash growth, are consistent with previously published findings. No new safety concerns were raised. This prospective study reaffirms that once-daily FCBT is a safe and well-tolerated therapy for OAG and OHT. GOV IDENTIFIER: NCT02571712.

The Role of Adaptive Immunity in Diabetic Retinopathy.

Diabetic retinopathy (DR) is currently one of the common causes of vision loss in working-age adults. It is clinically diagnosed and classified according to the vascular changes in the fundus. However, the activation of immune cells occurs before these vascular changes become detectable. These, together with molecular studies and the positive clinical outcomes of anti-inflammatory treatment, highlight the pivotal involvement of the immune system. The role of innate immunity in DR pathophysiology has been studied in depth, but the contribution of adaptive immunity remains largely elusive. This review aims to summarize our current understanding of the activation mechanism of adaptive immunity in DR microenvironments and to discuss the relationship between adaptive immunity and local vascular units or innate immunity, which opens new avenues for clinical applications in DR treatment.

Single-Cell Transcriptomic Profiling of Human Retinal Organoids Revealed a Role of IGF1-PHLDA1 Axis in Photoreceptor Precursor Specification.

Purpose: Cone and rod photoreceptors in the retina convert light to electrical signals which are transmitted to the visual cortex of the brain. Abnormal photoreceptor development and degeneration results in blindness. So far, the mechanism that controls photoreceptor specification and its subsequent fate bifurcation remain elusive. Methods: To trace and enrich the human photoreceptor lineage, we first engineered H9 human embryonic stem cell (hESC) reporter line by fusing EGFP to endogenous BLIMP1 using CRISPR/CAS9 gene-editing technology, and then used the cell line to generate 3D retinal organoids. Following EGFP-based cell sorting, single-cell RNA-sequencing was conducted via 10x Genomics Chromium system, and the data were analyzed using Seurat. Immunofluorescence combined with lentivirus-mediated knockdown and overexpression experiments were used as validation approaches. Results: Single-cell transcriptomic profiling revealed that retinal progenitor cells were temporally programmed to differentiate to cone and rod sequentially. We identified PHLDA1 as a novel regulator of photoreceptor specification. PHLDA1 mediated the effects of IGF1 through IGF1R, and inhibited AKT phosphorylation during photoreceptor development. Conclusions: Our data established a transcriptomic cell atlas of the human photoreceptor lineage, and identified IGF1-PHLDA1 axis to regulate human photoreceptor development.

m6A modification of circSPECC1 suppresses RPE oxidative damage and maintains retinal homeostasis.

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the elderly population with unclear pathogenic mechanism. Herein, we detect downregulated circSPECC1 expression in retinal pigment epithelium (RPE) of AMD patients. In RPE cells, circSPECC1 insufficiency leads to oxidative stress-induced ferroptosis, depolarization, and irregular lipid metabolism. Consistently, in mice, circSPECC1 deficiency induces visual impairments and RPE anomalies and interrupts retinal homeostasis. Mechanically, nuclear export of circSPECC1 transcript depends on its N6-methyladenosine (m6A) level with YTHDC1 as the reader. CircSPECC1 directly sponges miR-145-5p to block its interaction with CDKN1A. Overexpressing miR-145-5p aggravates RPE dysfunctions, mimicking circSPECC1 silencing effects. Retinal phenotypes induced by circSPECC1 insufficiency are alleviated by miR-145-5p inhibition and are aggravated by miR-145-5p overexpression. Collectively, circSPECC1, mediated by m6A modification and sponging miR-145-5p, resists oxidative stress injuries and maintains lipid metabolism in RPE. Pharmacological supplementation of circSPECC1 is a promising therapeutic option for atrophic retinopathies like AMD.