Investigative Opthalmology & Visual Science

PurposeAqueous humor outflow through the trabecular meshwork (TM) is segmental, demonstrating high flow (HF) and low flow (LF) regions. Here, we investigate transcriptomic differences between flow regions in naive mouse and non-glaucomatous human TM tissue to better understand intraocular pressure (IOP) regulation. MethodsHuman eyes (<6 hours postmortem) from two donors were perfused with a fluorescent tracer to identify HF and LF regions and fixed. In parallel, one pair of 8-month-old C57Bl/6J mouse eyes were similarly processed. Sagittal sections from HF and LF regions underwent whole-transcriptome spatial profiling. Differential expression and gene set variation analysis were conducted to identify transcript and pathway-level differences between HF vs. LF TM. Selected targets were validated by immunolabeling. ResultsGenes with relevance to TM outflow were identified as significantly differentially expressed in the human dataset, including ADAM metallopeptidase domain 15 (ADAM15), vimentin (VIM), chitinase 3-like 1 (CHI3L1), and several transcription factors (e.g., FOS, JUNB, ESR1). Pathways related to epigenetic modifications were also differentially enriched in human eyes. In both human and mouse eyes, myocilin was significantly upregulated in HF regions, despite greater protein labeling in LF regions of human eyes. In both species, rho-kinase signaling pathways showed increased enrichment in LF regions, while cell stress pathways, and TNF- signaling were increased in HF TM. ConclusionsHF regions maintain a more active stress response that facilitates greater outflow, whereas LF regions exhibit more matrix accumulation and contractility. This characterization of segmental flow regions can inform future studies to target trabecular outflow and lower IOP.

It is clear that the human retina and its underlying retinal pigment epithelium and choroid (RPE/choroid) form an interdependent metabolic ecosystem, but how metabolism differs between the cone-rich macula and rod-rich periphery remains unclear. Using targeted metabolomics, we quantified 133 metabolites in paired macular and peripheral neural retina and RPE/choroid explants from human donor eyes following short-term culture to restore metabolic activity. Distinct metabolic differences were identified between retinal regions and between tissues. Compared with the peripheral retina, the macula showed metabolic features consistent with greater glycolytic activity, increased NADH availability and higher levels of the neurotransmitter-associated metabolites N-acetyl-aspartate (NAA) and N-acetyl-aspartyl-glutamate (NAAG), consistent with increased energetic and neuronal activity. Compared with peripheral RPE/choroid, the macular RPE/choroid had higher levels of the flavin cofactor FAD together with NAD-related metabolites, including NAD, NADP and NAAD. Comparisons between the neural retina and RPE/choroid further showed that the neural retina was primarily associated with energy production and neurotransmission, whereas the RPE/choroid was associated with cofactor metabolism, nucleotide salvage and lipid metabolism. These findings are consistent with metabolic coupling between the neural retina and RPE/choroid. The macula has metabolic features consistent with high energetic demand, providing a potential metabolic basis for its selective vulnerability in macular disease.

Cone photoreceptors are essential for daylight vision, and their degeneration has more profound visual consequences than rod loss in retinal degenerative diseases. Metabolic dysfunction is closely associated with cone degeneration, however the relatively small population of cones in mice and humans have limited our understanding of cone-specific metabolism. Here, we leveraged cone-dominant and cone-degeneration mouse models including Nrl-/-, Cnga3-/-, and high-dose Triiodothyronine (T3) treatment to investigate cone-specific metabolism and their metabolic impacts on the retinal pigment epithelium (RPE). Across models, cone-dominant retinas consistently showed lower pyruvate abundance alongside increases in glutathione, purines, pentose phosphate pathway intermediates, and one-carbon metabolites. Increases in several key amino acids were also associated with higher cone abundance, such as proline, arginine, alanine, valine, leucine, and hypotaurine. Strikingly, aminoadipate, an intermediate in lysine catabolism, was the most robustly changed metabolite in the retina, showing highly consistent increases across models. Relative cone increases were also associated with metabolic changes in the RPE/choroid. Like the retina, RPE/choroids showed consistent increases in aminoadipate, proline, and hypotaurine, as well as xanthosine and betaine, alongside decreases in uracil. Moreover, proteomic analysis of Nrl-/- mice showed decreases in many key metabolite transporters in the RPE/choroid, including carriers for glucose, lactate, aspartate, glutamate, serine, lysine, taurine, and proline. Collectively, these findings further our understanding of cone-specific metabolism and highlight potential cone-specific metabolic vulnerabilities in retinal degeneration.

Purpose: To investigate the association between mitochondrial DNA (mtDNA) copy number (CN) and the rate of visual field progression in patients with primary open-angle glaucoma. Design: Retrospective cohort study Participants: 200 patients with primary open-angle glaucoma (POAG) with a mean of 11 years of longitudinal clinical data and DNA extracted from peripheral blood. Methods: DNA extraction was performed on peripheral blood leukocytes collected from 200 POAG patients who had an average follow-up of 11 years. Mitochondrial CN was quantified by multiplex quantitative TaqMan PCR using custom primers and probes against cytochrome b and beta-2 microglobulin as measures of mitochondrial and nuclear genes, respectively. Univariable and multivariable linear regression models were used to evaluate the association between mtDNA CN and rates of visual field progression, quantified by the slope of standard automated perimetry (SAP) mean deviation (MD) over time. Main Outcome Measures: Association of mtDNA CN with MD slope. Results: Mean mtDNA CN was 107.6 copies per cell (interquartile range, 70.5 to 126.7). Higher ln(mtDNA CN) was associated with slower rates of MD loss in both univariable (beta = 0.29, p < 0.001) and multivariable analyses (beta = 0.25, p = 0.003). Higher peak IOP was independently associated with faster visual field progression in both analyses. A significant interaction was observed between mtDNA CN and peak IOP (beta = -0.054, p < 0.001), with the association between lower mtDNA CN and faster SAP progression being more pronounced at lower levels of peak IOP. Conclusion: Lower mtDNA CN was associated with faster SAP progression, with the association being most pronounced at lower levels of peak IOP. These findings support mtDNA CN as a potential systemic biomarker of mitochondrial genomic reserve and susceptibility to visual field loss.

Purpose: To characterize the biomechanical response of the optic nerve head (ONH) in myopic versus non-myopic individuals with normal-tension glaucoma (NTG), and to evaluate the association between ONH strains and the rate of visual field (VF) progression. Design: Retrospective clinical cohort study. Participants: A total of 118 NTG eyes from 77 patients with [&ge;] 2 years of follow-up and 5 VF tests were enrolled, including 66 eyes with myopia and 52 eyes without. Methods: Each participant underwent three-dimensional (3D) optical coherence tomography (OCT) imaging of the ONH under three mechanical loading conditions: 20{degrees} adduction, 30{degrees} abduction and acute intraocular pressure (IOP) elevation by applying a 0.80 N force to the lower eyelid. Effective strains across the global ONH complex and within specific segmented tissues (pre-lamina, lamina cribrosa, choroid, and sclera) were quantified using a validated 3D strain-mapping algorithm. Results: Myopic NTG eyes exhibited significantly higher ONH strains compared to non-myopic eyes under acute IOP elevation (10.1{+/-}2.7% vs. 9.3{+/-}1.8%, P = 0.044) and abduction (9.2{+/-}2.3% vs. 8.4{+/-}2.1%, P = 0.048). In the non-myopic group, ONH strains varied significantly across conditions (P < 0.001), with adduction (9.9{+/-}2.0%) and acute IOP elevation (9.3{+/-}1.8%) eliciting greater strains than abduction (8.4{+/-}2.1%). These condition-dependent variations were less pronounced in the myopic group (10.1{+/-}2.7% vs. 9.8{+/-}2.7% vs. 9.2{+/-}2.3%, P = 0.07). Multivariable linear mixed-effects analysis revealed that in myopic NTG, higher ONH strains induced by adduction were significantly associated with faster MD decline (estimate: -0.139 dB/year per 1% increase, P = 0.03, adjusted for age, spherical equivalent and baseline perimetric mean defect). Conversely, larger strains during acute IOP elevation were associated with slower progression (estimate: 0.184 dB/year per 1% increase, P = 0.004). Tissue-specific analysis confirmed that adduction-induced strains in the choroid and pre-lamina tissue as well as IOP-induced strains across all ONH tissues were significantly correlated with the rate of perimetric progression in myopic eyes (all P < 0.05). Conclusions: In this cohort, greater adduction-induced ONH strain was associated with faster perimetric deterioration in myopic NTG. These findings support further investigation of gaze-related optic nerve traction as a potential non-IOP-related biomechanical factor in myopic NTG. Keywords: Normal tension glaucoma, Myopia, Optic nerve head, Ocular biomechanics, Visual field Progression, adduction.

Purpose: To understand the functional impact of macular atrophy (MA) and fibrosis in eyes with treated neovascular age-related macular degeneration (nAMD) based on deep visual sensitivity losses. Design: Cross-sectional study. Participants: One-hundred and nine eyes from 97 individuals with nAMD that had been treated for >=12 months without significant retinal fluid. Methods: All participants underwent defect-mapping microperimetry (DMP) testing - a strategy optimized to quantify the spatial extent of deep visual sensitivity losses through single 10 decibel stimuli presentations - where 208 locations were sampled in the central 8 degrees radius region. Participants also underwent color fundus photography, fundus autofluorescence and OCT imaging, which were co-registered and manually annotated for MA and fibrosis to determine their two-dimensional pointwise extent at individual test locations, and global extent in the corresponding region where DMP was performed. Main Outcome Measures: Pointwise association between the presence of MA and fibrosis with missing a stimulus on DMP and global association between the extent of MA and fibrosis with the proportion of locations missed (PLM) on DMP. Results: At a pointwise level, the presence of MA and fibrosis were independently associated with an increased likelihood of missing a stimulus on DMP (odds ratio = 42.5 and 2.5 respectively; P < 0.001 for both). However, at a global level, only an increasing extent of MA was associated with a significantly higher PLM on DMP (P < 0.001), but not fibrosis (P <= 0.227). MA extent explained a substantial proportion of the variance in the PLM (R2 = 0.97) and there was a very strong correlation between the two parameters ({rho} = 0.93). Conclusions: This study confirmed the expected functional impact of MA and fibrosis on DMP testing at a pointwise level. However, it showed at the global level that only the extent of MA, and not fibrosis, was independently associated with functional loss on DMP, and that there was a very strong structure-function correlation based on MA. These findings thus suggest that evaluating MA alone may be sufficient for capturing structural changes strongly associated with the global extent of deep visual sensitivity losses in those with treated nAMD.

Purpose: To test whether juvenile open-angle glaucoma (JOAG) and primary congenital glaucoma (PCG) are polygenically continuous with primary open-angle glaucoma (POAG), using a multi-trait POAG polygenic risk score (PRS). Design: Retrospective cohort study. Participants: 3,102 open-angle glaucoma index cases, of whom 2,836 had a recorded age at diagnosis (52 PCG, 226 JOAG, and 2,558 POAG) and 999 European-ancestry controls from a glaucoma disease registry and a population-based cohort. Two replication cohorts comprised 70 JOAG and 31 PCG probands with 230 controls (Mass Eye and Ear, MEE), and 9 PCG and 120 POAG cases (Genetics of Glaucoma Study, GOGS). Methods: One index case per family was analysed. PRS were calculated from weighted SNPs and adjusted for ancestry. Cases were stratified by age at diagnosis (PCG <=3 years, JOAG >=4 and <40 years, POAG >=40 years) and presence of pathogenic/likely pathogenic variants ("Mendelian"). Groups were compared by Kruskal-Wallis test, with logistic regression and area under the curve for per-SD effects. Main Outcome Measures: PRS centile values compared across glaucoma subtypes and Mendelian and non-Mendelian subgroups. Results: Mean PRS was highest in cases diagnosed in the fourth decade of life. Among subgroups, it was highest in non-Mendelian JOAG (84.1%), exceeding controls (53.3%), Mendelian JOAG (68.9%), and non-Mendelian POAG (79.3%) (all P <= 0.003). Non-Mendelian JOAG was also the best discriminated from controls (OR 3.66 per SD increase, 95% CI 3.02-4.49; AUC 0.814, 95% CI 0.782-0.845). Neither PCG subgroup differed from controls. Among Mendelian cases, only MYOC p.Gln368Ter showed significantly elevated PRS (OR 2.49 per SD, 95% CI 1.89-3.34). In the MEE replication cohort, JOAG was associated with higher PRS (OR 2.12 per SD, 95% CI 1.50-3.07) while PCG was not (OR 0.90, P = 0.73). In GOGS, mean PRS was higher in POAG than PCG (84.8 vs 59.7 centile; P = 0.026). Conclusions: A POAG PRS predicts JOAG risk with discrimination comparable to or greater than POAG itself, supporting a shared polygenic architecture across juvenile and adult open-angle glaucoma. PCG showed no PRS elevation regardless of Mendelian status, indicating a distinct architecture for which rare-variant sequencing remains appropriate.

Fuchs endothelial corneal dystrophy (FECD) is a disease of the corneal endothelium (CE) characterized by the loss of corneal endothelial cells (CECs) and guttae formation, ultimately resulting in corneal edema and vision loss. FECD primarily affects the central CE while sparing the peripheral CE, however the underlying mechanism contributing to the spatial differences remain unknown. Oxidative stress has been increasingly recognized as a key contributor to the pathogenesis of FECD, with CECs being particularly susceptible to damage from reactive oxygen species (ROS), high metabolic activity and ultraviolet induced DNA damage. The non-proliferative nature of CECs, along with the accumulation of oxidative damage can ultimately lead to CEC loss, a key feature of FECD. In this study, we induced oxidative stress with hydrogen peroxide (H2O2) on ex-vivo corneal specimens and observe increased cell death in the central region compared to the peripheral CE. To investigate these underlying differences, we performed bulk RNA sequencing (RNA-seq) on the central and peripheral regions of CE from FECD and normal cadaveric donors. Pathway analysis identified an enrichment of genes involved in collagen and extracellular matrix between the central and peripheral regions of CE in both normal and FECD, as well as between normal and FECD CE. Intriguingly, we identified the long non-coding RNA (lncRNA), NEAT1 as a top differentially expressed gene, with reduced expression in the central CE compared to the peripheral CE and lower expression in FECD compared with normal CE. Using corneal endothelial cell lines and ex-vivo specimens from FECD patients and normal cadavers, we found decreased NEAT1 expression levels in FECD and increased susceptibility to H2O2-induced oxidative stress. We observed that NEAT1 knockdown in normal and FECD cells exacerbated H2O2-mediated oxidative stress, and that NEAT1 overexpression protected FECD cells. We report in this study, a novel insight in the spatial differences in gene expression in the CE and identify reduced expression of NEAT1 in the central CE as a potential contributor to oxidative stress-related cell death in FECD. These findings provide novel insight into FECD pathogenesis and why FECD pathology preferentially affects the central CE. Antioxidants targeting NEAT1 signaling could be developed into novel therapeutics aimed at preventing FECD pathogenesis.

Purpose: Oxidative stress is thought to contribute to the development of age-related cataracts (ARCs), but the mechanisms by which oxidative damage leads to the opacification of the lens remain unclear. Previous studies suggest that oxidative stress can disrupt lens proteostasis. Therefore, it was hypothesized that ARCs arise from proteomic changes driven by an age-associated decline in oxidative stress defenses that interact with the lens proteostatic state. To test this hypothesis, proteomic analyses of lenses exposed to oxidative stress were performed to examine oxidative and proteostatic stress responses in vivo. Methods: Cataract formation was induced by injecting hydrogen peroxide into the aqueous humor of adult zebrafish. nrf2fh318/fh318 zebrafish were used to model the reduced oxidative stress protection observed in aged human lenses, while cryaba-/- zebrafish were used to model impaired lens proteostasis. Resulting opacities in WT, cryaba-/-, nrf2fh318/fh318, and cryaba-/-; nrf2fh318/fh318 lenses were quantified and proteomic changes in the cortex were analyzed using data independent acquisition Parallel Accumulation Serial Fragmentation mass spectrometry. Results: Hydrogen peroxide treatment induced the formation of cortical cataracts. Proteomic results showed that, dependent on genotype and day, oxidative stress activates the unfolded and mitochondrial unfolded protein responses. Additional changes were also observed in energy metabolism, Ca2+ homeostasis, protein degradation, and cytoskeletal and extracellular matrix remodeling pathways. Conclusions: Treated zebrafish lenses successfully model ARC and mass spectrometry proteomics identified the unfolded and mitochondrial unfolded protein responses as potential therapeutic targets for ARC.

Background/Objectives: Previous OCTA studies across MacTel severity levels have primarily characterised perfusion- and density-based vascular changes. Whether graph-derived network architecture provides complementary information on severity remains unclear. We therefore tested whether lower Chew grades already show architectural abnormalities despite comparatively preserved global vessel density. Subjects/Methods: This cross-sectional study included 62 MacTel and 64 healthy control eyes. Fovea-centred 3x3-mm high-resolution swept-source OCTA acquired with the DREAM platform was analysed with OCTAVA. Whole-image vessel length density (VLD), regional vessel area density (VAD), peri-FAZ perfusion, foveal avascular zone (FAZ) geometry and network topology were assessed using mixed-effects models adjusted for age, sex and axial length. Results: Grades 0-2 already showed greater FAZ acircularity than controls in the superficial (SCP; +0.132; q<0.001) and deep capillary plexus (DCP; +0.073; q=0.034), with lower SCP branchpoint density (q=0.022). Across MacTel grades, DCP VLD decreased by 0.352 mm-1 per grade (95% CI -0.583 to -0.121; Holm P=0.007), whereas the SCP slope was not significant (Holm P=0.071; plexus interaction P=0.160). DCP parafoveal VAD declined by 0.593 percentage points per grade (95% CI, -0.943 to -0.242; q=0.007), with no comparable decline in foveal VAD. Visual acuity worsened by 0.071 logMAR per grade (P<0.001). Conclusions: OCTA suggests two complementary components of the MacTel vascular phenotype: geometric and topologic remodelling in lower grades, with additional regional and global capillary rarefaction in higher grades. Vascular geometry and network topology, therefore, provide complementary information not captured by vessel density alone.

Purpose: The neural retina and retinal pigment epithelium/choroid (RPE/Cho) are metabolically coupled. Metabolic dysfunction of the RPE/Cho contributes to photoreceptor death in age-related macular degeneration (AMD). This study aimed to determine how aging, a major risk factor for AMD, alters the proteome and metabolic pathways in the retina and RPE/Cho. Methods: We performed quantitative proteomics on neural retina and RPE/Cho from young (8-week) and old (73-week) C57BL/6J mice. The differentially expressed proteins between old and young, as well as between the retina and RPE/Cho, were visualized using volcano plots and heatmaps, and functional analyses were assessed by Gene Ontology enrichment tools. Results: Aging altered the expression of 85 retinal proteins and 272 RPE/Cho, with 16 shared between tissues. In the aged retina, proteins associated with NADP(H) metabolism, neurodegeneration, and immunity were mostly upregulated, while proteins in lipid metabolism, transcription, and epigenetic regulation decreased. In the aged RPE/Cho, all 21 significantly altered lysosomal enzymes and transport proteins increased, together with complement components, and photoreceptor outer segment proteins. These changes accompanied increases in proteins associated with lipid metabolism and protection against lipid peroxidation, while several glutathione metabolism enzymes decreased. Seven shared proteins involved in lipid and NADP(H) metabolism, changed in opposite directions between retina and RPE/Cho. Comparison of the retinal and RPE/Cho proteomes identified 3073 differentially abundant proteins, of which 2452 maintained tissue-specific differences across both age groups, while approximately 17% showed age-dependent shifts in tissue enrichment. These shifts involved proteins associated with metabolism, extracellular matrix, visual function, lysosomal pathways, and innate immunity. Within the metabolic proteome, several glycolytic and fatty acid oxidation proteins showed greater relative enrichment in RPE/Cho with age, whereas glucose transporters and mitochondrial complexes shifted toward the retina. Conclusions: Overall, these findings show that aging differentially remodels the retina and RPE/Cho proteome, accompanied by altered metabolic specialization between the two tissues.

Glaucoma is an irreversible blinding disease that affects millions of individuals worldwide. Elevated intraocular pressure (IOP), regulated by the trabecular meshwork (TM) in the anterior eye, is the only modifiable risk factor. Human TM cells can be cultured from donor eyes, providing a precious resource for studying factors that induce or prevent glaucoma. The goal of this study was to produce datasets that define the molecular profile of human non-glaucomatous TM cells. Using 18 human TM cell strains cultured from non-glaucomatous individuals deposited from seven laboratories in the USA and UK, this study used transcriptomic, proteomic, lipidomic, and metabolomic analyses to characterize the molecular content of TM cells. The data herein provides the most comprehensive multiomic analyses of human TM cells to date and will be a useful resource for researchers and clinicians in the TM and glaucoma fields.

PLCXD proteins have been linked to phosphoinositide metabolism for more than a decade, and PLCXD2 activity has been associated with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] depletion, yet its preferred direct substrate has remained unresolved. Here, cellular lipidomics showed that catalytically active PLCXD2 reduced the major phosphatidylinositol (PI) 38:4 species, with more modest phosphoinositide changes and increased diacylglycerol (DAG) and phosphatidic acid (PA). Using recombinant PLCXD2 and acyl-chain-matched substrates, we found that PLCXD2 hydrolyzed PI substantially more efficiently than PI(4,5)P2 and most other phosphoinositides tested. In Plcxd2-deficient retina, PI abundance was preserved, whereas DAG and PA were reduced without broad changes in major membrane phospholipid classes. PLCXD2 loss was associated with early structural abnormalities at the photoreceptor-bipolar synaptic interface, followed by outer nuclear layer thinning and reduced electroretinographic a-wave responses. These findings identify PLCXD2 as a PI-preferring mammalian PLC and reveal an endogenous role in retinal lipid homeostasis and outer retinal integrity.

PurposeFuchs endothelial corneal dystrophy (FECD) is a progressive disease, causing premature death of corneal endothelial cells (CECs). Iron-dependent lipid peroxidation and ferroptosis mediate cell death in FECD. We aimed to determine whether FECD progression is mediated by derangements in ferritinophagy - a form of autophagy that degrades ferritin to release labile ferrous iron - and whether ultraviolet A (UVA) exposure drives FECD progression by activating ferritinophagy. MethodsEndothelium-Descemet membrane (EDM) tissues were collected from patients with end-stage FECD undergoing endothelial keratoplasty and from healthy age-matched donor corneas. Separately, immortalized FECD and healthy control CEC lines were cultured. Cellular levels of NCOA4 production and LC3 activation, both markers of ferritinophagy, were quantified using western blotting and PCR. UVA-exposed immortalized cells were plated on coverslips, stained for immunohistochemistry (IHC), and analyzed using confocal microscopy. Corneal endothelial peels were stained and analyzed using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). ResultsSurgically explanted FECD CECs showed significantly increased levels of NCOA4 compared to healthy controls. LC3 activation was increased in FECD immortalized CECs; UV exposure further increased LC3 activation. Additionally, UVA exposure showed trends of increased expression of NCOA4 in immortalized FECD and healthy CECs. On IHC of FECD surgical explant tissue, ferritin was decreased markedly, NCOA4 localized in a dramatic punctate pattern, and both ferritin and LC3 localized within cell nuclei. Spectrometry images showed higher iron levels correlating with areas of higher FECD disease burden. ConclusionsOur results demonstrate ferritinophagy in FECD indicated by the increase of NCOA4 and LC3 ferritinophagy markers in FECD patient and cell culture models. Our finding that UVA activates ferritinophagy implicates this mechanism in UVA-mediated FECD progression. Altogether, aberrant iron dysregulation associated with FECD and ferroptosis may be mediated by ferritinophagy, providing a biomarker to assess disease severity as well as a potential target for future medical therapeutics.

Purpose: Age is the leading factor for age-related macular degeneration (AMD), in which retinal pigmented epithelium (RPE) atrophy is a hallmark. The nuclear factor-erythroid 2-related factor 2 (Nrf2), a major anti-stress transcription factor, decreases in AMD, suggesting bioenergetic stress interacts with age during AMD pathogenesis. We profiled visual function and gene expression of the retina and RPE-choroid with Nrf2 deletion and aging. Methods: We tested 3mo and 14mo Nrf2 null (Nrf2 KO) and Nrf2 WT mice for optokinetic tracking (OKT) and dark-adapted electroretinography (ERG) responses. Eyes were harvested for retina outer nuclear layer (ONL) thickness analysis and retina and RPE-choroid cup RNA isolation for RNAseq profiling. Results: Visual acuity was reduced with aging with lower values in the Nrf2 KO vs Nrf2 WT comparison at 14mo. We observed aged-related reduction of a-, b-, and c-wave ERG amplitudes in both WT and KO mice. Age-related c-wave decline was exacerbated by Nrf2 loss. By RNAseq, two-way ANOVA of RPE-choroid samples revealed differentially expressed genes (DEGs) with age and genotype main effects, as well as DEGs with age and genotype interaction effects. Age DEGs were over-represented in pathways related to inflammation and phagocytosis. Genotype DEGs were associated with alterations in antioxidant and inflammatory processes. Retina RNAseq showed age and genotype DEGs. Conclusions: Ablation of Nrf2 exacerbates age-related declines suggesting that decrease in Nrf2 with aging has functional consequences for inflammation/resiliency. We provide retina and RPE-choroid bulk-RNAseq datasets from the same cohort of mice that can be interrogated to better understand degeneration of retina/RPE-choroid.

Iris biomechanics plays a key role in primary angle-closure glaucoma (PACG). Soft tissue biomechanics is heavily influenced by tissue water content; therefore, accurately assessing water content is needed to describe iris biomechanics in a physiologically relevant manner. Yet, accurate experimental measurements of iris water content are rare in the literature. Therefore, our objective was to experimentally assess iris water content and potential sex differences in New Zealand White rabbit iris--a suitable model for studying iris biomechanics. We also examined the effect of exposure to phosphate-buffered saline (PBS) on iris water content, given its common use to maintain hydration during soft-tissue biomechanical testing. Our results showed slightly higher water content in males (89.2% {+/-} 2.3%) than in females (87.7% {+/-} 2.2%) (p = 0.022), while we found no significant differences in gross iris morphology between the sexes, indicating subtle compositional differences. Furthermore, PBS incubation had a minimal effect on water content only in female irides. Overall, our results indicated high iris water content in both sexes compared with anatomically adjacent ocular tissues and other soft connective tissues. These results improve our understanding of iris composition and physiology and can serve as a baseline for constructing biomechanical models to assess its role in PACG.

Age-related macular degeneration (AMD) is among the leading causes of blindness worldwide. Early AMD is characterized by dysfunction in the choroid, including early dropout of endothelial cells and increased deposition of the complement cascade's membrane attack complex (MAC) in the choriocapillaris. In this study, we used a single-cell RNA sequencing-based approach with barcoded antibodies to measure abundance of the MAC and other surface proteins at single cell resolution on RPE/choroid samples from four aged human donor eyes. We included antibodies to detect the MAC, CD34, CD45, and complement regulators CD55 and CD59, in addition to control antibodies. Our analysis of these data revealed cell clusters with expected gene expression profiles and antibody-based detection of CD34 and CD45 congruent with transcriptome-based cell identity. We also detected surface complement regulators CD55 and CD59 across a wide variety of cell types. Across endothelial cells, surface CD55 and CD59 appeared more abundant on venous clusters, and abundance of each was correlated with expression of a third complement regulator, clusterin (CLU). The MAC was detected on a variety of cell types, but was most abundant on the surface of cells in the macrophage family, smooth muscle cells, and pericytes. We confirmed these findings by identifying MAC deposition on choriocapillaris pericytes using immunohistochemistry for MAC, endothelial, and pericyte markers. Ultimately, these data showcase a valuable new approach to analyze gene expression and surface complement in human donor eyes, and provide novel insight into patterns of MAC deposition and complement protection in the aging human choroid.

Genetic variants in PROM1 are associated with inherited blindness, but clinical phenotypes vary widely with currently no consensus on disease expectations or predicted patient outcomes. To address this issue, we performed chi-square correlation analysis on 190 published pathogenic and likely pathogenic variants from ClinVar Miner and the Human Gene Mutation Database. We identified a statistically significant increase in observed cases of dominantly inherited missense variants, which were associated with milder forms of macular dystrophy. Recessive inheritance of truncating frameshift variants was associated with more severe forms of inherited retinal degeneration such as rod-cone dystrophy. We also present case studies from 7 patients with phenotypes that are unique, unreported, or do not match the reported phenotype in online databases. We report two patients with VUS that have clinical phenotypes and dominantly inherited missense variants, one patient with a long natural history at our clinic, two patients with the same variant, but a different clinical diagnosis, and two patients with retinal deposits comprising subretinal drusenoid deposits (SDD) and soft drusen.

Tear fluid is amenable to non-invasive and repeated collection, making it a practical specimen for evaluating exercise-related physiological responses. However, the immediate proteome-wide alterations in tear fluid following acute exercise have not been characterised. In this study, we performed quantitative proteomic profiling of paired tear samples from healthy female participants before and immediately after a single exercise session using data-independent acquisition liquid chromatography-tandem mass spectrometry (DIA-LC-MS/MS). Among the 3,173 identified proteins, 744 were significantly altered post-exercise, of which 484 were up-regulated and 260 down-regulated. Functional enrichment analysis revealed that up-regulated proteins were predominantly associated with translation and ribosome biogenesis, whereas down-regulated proteins were involved in glycan metabolism, lysosomal processing, and extracellular matrix organisation. Collectively, these findings indicate that acute exercise elicits a rapid and coordinated reconfiguration of the tear proteome. This investigation provides a molecular basis for understanding exercise-mediated modulation of tear composition and ocular surface homeostasis.

Traumatic optic neuropathy (TON) occurs due to direct or indirect injury to the optic nerve and is a significant cause of visual disability. So far, there is no effective treatment. The lack of understanding of the cellular mechanisms by which trauma induces inflammation and damage in retinal neurons is a critical knowledge gap in developing effective therapies. We have studied the role of the arginase 1 (A1) enzyme in this pathology. We have found previously that treatment with a long-acting form of human recombinant A1, pegylated A1 (PEG-A1) after optic nerve crush limits activation of retinal microglia and macrophages (M{Phi}) and reduces inflammation, thereby decreasing injury and protecting visual function. Here we report on studies designed to demonstrate the therapeutic efficacy of PEG-A1 in mouse models of direct and indirect TON and to elucidate the underlying mechanisms. We used ONC to model direct TON and sonication-induced trauma to the supraorbital rim to model indirect TON (SI-TON). At different times after injury, mice were treated with PEG-A1 which was delivered systemically by i.p. injection or locally by intravitreal injection. In order to assess the role of A1-induced activation of the ornithine/polyamine pathway in the protective effects of PEG-A1, some mice were treated with the ornithine decarboxylase (ODC) inhibitor, difluoromethylornithine (DFMO) immediately after the PEG-A1 treatment. Retinal function was determined by OptoMotry and electroretinography. Retinal injury and microglia/M{Phi} activation were assessed by immunofluorescence imaging. Expression of inflammatory cytokines was determined by Western blotting and quantitative RT PCR. Liquid chromatography mass spectrometry was used to analyze changes in arginase/ODC pathway metabolites. Results showed that PEG-A1 treatment improved neuronal survival and visual function whether delivered systemically or intravitreally. This neuroprotection was associated with decreased microglia/M{Phi} activation, decreased inflammatory cytokine expression, and increased formation of L-ornithine and putrescine. Furthermore, DFMO treatment blocked these effects, indicating that PEG-A1 limits retinal injury and preserves vision after ocular injury by activating ODC. ODC processes the arginase product L-ornithine to form polyamines which are known to promote reparative functions. Thus, PEG-A1 therapy offers a new strategy to limit trauma-induced vision loss and promote repair after TON.