Pathogenesis Of Primary Open-angle Glaucoma Research Articles

Genetic Insights and Epidemiological Models in Understanding Primary Open Angle Glaucoma

Primary open-angle glaucoma (POAG) is a multifactorial chronic optic neuropathy with significant genetic heterogeneity. The pathogenesis of POAG involves an imbalance between the production and drainage of aqueous humor (AH). Genetic theories suggest that transgenic mice demonstrating the GLU50LYS mutation in optineurin (OPTN) experience retinal ganglion cell apoptosis, while mutant myocilin (MYOC) proteins induce endoplasmic reticulum (ER) stress, leading to an unfolded protein response (UPR) and subsequent apoptosis of trabecular meshwork cells (TMC). Furthermore, the interaction between MYOC and mitochondria in the trabecular meshwork (TM) and astrocytes may lead to mitochondrial membrane depolarization and calcium channel dysregulation, contributing to POAG. Overexpression of MYOC variants (P370L, Q368X) is also implicated, as are epigenetic modifications and signaling pathways such as histone and DNA modification. POAG has been associated with autosomal dominant inheritance, with mutations in MYOC and OPTN being prominent causative factors, although many cases involve multiple genetic loci. Currently, over 20 genetic loci have been linked to POAG, with 14 chromosomal loci (GLC1A to GLC1N) identified, 5 of which contribute to juvenile-onset open-angle glaucoma (JOAG). Of these loci, MYOC, OPTN, WD repeat domain 36 (WDR36), and neurotrophin-4 (NTF4) are the most studied causative genes. The ongoing study of molecular genetics offers potential pathways for future therapeutic advances in the treatment of POAG.

Exploring the Relation Between Peripapillary Retinal Vessel Caliber and Visual Field Defects in Primary Open-Angle Glaucoma.

Background Primary open-angle glaucoma (POAG) is a progressive optic neuropathy characterized by loss of retinal ganglion cells, optic nerve head changes, and visual field defects. Vascular factors, alongside intraocular pressure, play a crucial role in POAG pathogenesis, and this study aims to explore the relationship between retinal vessel caliber and visual field defects in POAG patients. Purpose To evaluate the association between retinal vessel calibers in the peripapillary area with visual field defects in one or both hemifields. Materials and Methods This cross-sectional study was conducted at a tertiary eye care center in northern Karnataka for one year, enrolling 100 eyes from 50 primary open-angle glaucoma (POAG) patients with visual field abnormalities. Fundus color stereoscopic photographs were taken using a Canon digital camera, and diameters of the superior and inferior temporal arteries (STA and ITA) and veins (STV and ITV) in the peripapillary area were measured. Visual field defects were categorized, and statistical analyses were performed to correlate retinal vessel calibers with field defect locations. Results Participants had a mean age of 89.68 years, with 72% male. Visual field defects included superior arcuate scotoma (20%), inferior arcuate scotoma (32%), double arcuate scotoma (30%), and tubular vision (18%). Significant vessel caliber changes were observed: for superior hemifield defects, the mean STA: ITA ratio was 1.15 (p = 0.001), and for inferior defects, it was 0.94 (p = 0.04). STV: ITV ratios also showed significant changes corresponding to visual field defects. Eyes with defects in both hemifields showed pronounced narrowing, particularly in inferotemporal vessels. Conclusions Decreased retinal vessel caliber is significantly associated with visual field defects in primary open-angle glaucoma and can be a valuable diagnostic parameter tool for assessing glaucomatous damage and the progression and severity of POAG.

Decrease of Prolylcarboxypeptidase Dose of Aqueous Humor is Involved in the Pathogenesis of Primary Open-Angle Glaucoma via Finetuning of the Local Ocular Renin-Angiotensin System.

In this study, we investigated the cause of the AngII dose elevation in aqueous humor of primary open-angle glaucoma (POAG) patients. Enzyme-linked immunosorbent assay (ELISA), western blotting were used to detect concentration of Angiotensin Converting Enzyme 2 (ACE2) and Prolylcarboxypeptidase (PRCP). AngII and AngII + Recombinant PRCP were injected into anterior chamber of mouse eye. Mouse Intraocular pressure (IOP) was measured every week, mouse eye sections were conducted Hematoxylin-and-Eosin (H&E) staining, Masson' staining and Immunofluorescence staining. Western blotting and Immunofluorescence staining assays to detected fibrosis of trabecular meshwork cells. Mass spectrometry was used to identify proteins of aqueous humor. PRCP dose are decreased in aqueous humor of POAG patients. There is a negative correlation between PRCP and AngII levels in aqueous humor and between PRCP levels and the IOP. PRCP treatment reverses fibrosis of trabecular meshwork (TM) and prevents IOP elevation induced by AngII. Exogenous PRCP rescues fibrosis induced by AngII in HTMCs. Proteome profiling detected 502 differentially expressed proteins. Our study found PRCP dose was decreased in POAG patients' aqueous humor, and it might cause high level of AngII. Restoration of PRCP rescued fibrosis of TM cells and ameliorated IOP in AngII treatment mouse.

Establishment of a Disease Model Using Patient-Specific Induced Pluripotent Stem Cells-Derived Trabecular Meshwork Cells in a Chinese Primary Open-Angle Glaucoma Mega-Pedigree.

Primary open-angle glaucoma (POAG) is one of the most common insidious blinding eye diseases. Understanding the pathogenic mechanisms of it is extremely important. It is accepted that POAG attacks specific ocular tissue, such as trabecular meshwork and optic nerve damage, which causes elevated intraocular pressure and optic nerve damage. This study aimed to develop a preliminary prediction model for this disease by establishing the patient-specific induced pluripotent stem cells (iPSCs)-derived trabecular meshwork cells (TMCs) (p-iPSCs-TMCs) in the largest POAG family named "GZ.1" in China and preliminarily analyze the pathogenic mechanisms. Peripheral blood of patients in GZ.1 and healthy individuals not belonging to the family were collected and reprogrammed into iPSCs. Then, the iPSCs were differentiated into iPSCs-TMCs. Next, their morphology and function were compared. Finally, their pathogenic mechanisms were analyzed. The patient-specific iPSCs (p-iPSCs) and healthy individual-specific iPSCs (n-iPSCs) were all successfully generated. Their morphology was quite similar to each other. However, p-iPSCs-TMCs exhibited compromised morphology and function. p-iPSCs-TMCs displayed the morphology of heterogeneous distribution and accumulation in clusters, while n-iPSCs-derived TMCs (n-iPSCs-TMCs) showed a uniformly distributed and homogenous appearance. Moreover, p-iPSCs-TMCs showed greater cell apoptosis (p < 0.01), impaired proliferating ability (24-h and 48-h time points: p < 0.05, 72-h and 96-h time points: p < 0.001), production of reactive oxygen species (p < 0.05), and impaired phagocytosis ability than n-iPSCs-TMCs (24-h, 48-h, and 72-h time points: p < 0.0001, 96-h time point: p < 0.001). The p-iPSCs-TMCs can be successfully differentiated from peripheral blood, while the cells show impaired morphology and function compared with n-iPSCs-TMCs. Given this, p-iPSCs-TMCs can serve as an ideal disease model for POAG in GZ.1. Our study on the morphology and function of iPSCs-TMCs in GZ.1 may provide a valuable tool for elucidating the pathogenesis of POAG.

Identification of Optic Nerve-Related Biomarkers in Primary Open-Angle Glaucoma Based on Comprehensive Bioinformatics and Mendelian Randomization.

Glaucoma is the primary cause of permanent vision loss worldwide. However, the pathogenesis of primary open-angle glaucoma (POAG), the main type of glaucoma, has not yet been completely understood. In our study, the POAG cohorts were obtained from the Gene Expression Omnibus (GEO) database (GSE45570). Biomarkers with diagnostic utility for POAG were identified through combining differentially expressed analysis, enrichment analysis, machine learning algorithms, and receiver operating characteristic (ROC) analysis. The regulatory networks (including a competing endogenous RNA (ceRNA) regulatory network and a small molecule compounds-mRNA network) were created. In addition, the Mendelian randomization (MR) analysis was used to identify exposures causally associated with POAG. Finally, the expression of the biomarkers was validated via real-time quantitative polymerase chain reaction (RT-qPCR). The Gene Ontology (GO) items that the differentially expressed genes (DEGs) between POAG and control groups enriched were relevant to light stimulation and DNA methylation. A total of three light stimulation-related biomarkers (RAB8A, PRG3, and SMAD3) were identified, which had diagnostic value for POAG patients. Besides, the ceRNA regulatory network contained 88 nodes and 93 edges, and a small molecule compounds-mRNA network included 66 nodes and 76 edges. The MR results indicated a causal association between DNA methylation GrimAge acceleration and POAG. Additionally, the results of RT-qPCR revealed that the expression trend of RAB8A was consistent with that of GSE45570. Taken together, this study provides three light stimulation-related biomarkers (RAB8A, PRG3, and SMAD3) for the diagnosis of POAG, providing scientifically valuable insights for further studies of POAG. Discovering biomarkers that possess diagnostic significance for POAG has the potential to offer new insights into the pathogenesis of POAG and present novel objectives for clinical intervention.

Aqueous humor TGFβ and fibrillin-1 in Tsk mice reveal clues to POAG pathogenesis

Aqueous humor (AH) and blood levels of transforming growth factor β (TGFβ) are elevated in idiopathic primary open angle glaucoma (POAG) representing a disease biomarker of unclear status and function. Tsk mice display a POAG phenotype and harbor a mutation of fibrillin-1, an important regulator of TGFβ bioavailability. AH TGFβ2 was higher in Tsk than wild-type (WT) mice (by 34%; p = 0.002; ELISA); similarly, AH TGFβ2 was higher in human POAG than controls (2.7-fold; p = 0.00005). As in POAG, TGFβ1 was elevated in Tsk serum (p = 0.01). Fibrillin-1 was detected in AH from POAG subjects and Tsk mice where both had similar levels relative to controls (p = 0.45). 350 kDa immunoblot bands representing WT full-length fibrillin-1 were present in human and mouse AH. A 418 kDa band representing mutant full-length fibrillin-1 was present only in Tsk mice. Lower molecular weight fibrillin-1 antibody-reactive bands were present in similar patterns in humans and mice. Certain bands (130 and 32 kDa) were elevated only in human POAG and Tsk mice (p ≤ 0.04 relative to controls) indicating discrete isoforms relevant to disease. In addition to sharing a phenotype, Tsk mice and human POAG subjects had common TGFβ and fibrillin-1 features in AH and also blood that are pertinent to understanding glaucoma pathogenesis.

High throughput functional profiling of genes at intraocular pressure loci reveals distinct networks for glaucoma.

Primary open angle glaucoma (POAG) is a leading cause of blindness globally. Characterized by progressive retinal ganglion cell degeneration, the precise pathogenesis remains unknown. Genome-wide association studies (GWAS) have uncovered many genetic variants associated with elevated intraocular pressure (IOP), one of the key risk factors for POAG. We aimed to identify genetic and morphological variation that can be attributed to trabecular meshwork cell (TMC) dysfunction and raised IOP in POAG. 62 genes across 55 loci were knocked-out in a primary human TMC line. Each knockout group, including five non-targeting control groups, underwent single-cell RNA-sequencing (scRNA-seq) for differentially-expressed gene (DEG) analysis. Multiplexed fluorescence coupled with CellProfiler image analysis allowed for single-cell morphological profiling. Many gene knockouts invoked DEGs relating to matrix metalloproteinases and interferon-induced proteins. We have prioritized genes at four loci of interest to identify gene knockouts that may contribute to the pathogenesis of POAG, including ANGPTL2, LMX1B, CAV1, and KREMEN1. Three genetic networks of gene knockouts with similar transcriptomic profiles were identified, suggesting a synergistic function in trabecular meshwork cell physiology. TEK knockout caused significant upregulation of nuclear granularity on morphological analysis, while knockout of TRIOBP, TMCO1 and PLEKHA7 increased granularity and intensity of actin and the cell-membrane. High-throughput analysis of cellular structure and function through multiplex fluorescent single-cell analysis and scRNA-seq assays enabled the direct study of genetic perturbations at the single-cell resolution. This work provides a framework for investigating the role of genes in the pathogenesis of glaucoma and heterogenous diseases with a strong genetic basis.

Next-generation sequencing-based gene panel tests for the detection of rare variants and hypomorphic alleles associated with primary open-angle glaucoma.

Primary open-angle glaucoma (POAG) is a complex disease with a strong hereditably component. Several genetic variants have recently been associated with POAG, partially due to technological improvements such as next-generation sequencing (NGS). The aim of this study was to genetically analyze patients with POAG to determine the contribution of rare variants and hypomorphic alleles associated with glaucoma as a future method of diagnosis and early treatment. Seventy-two genes potentially associated with adult glaucoma were studied in 61 patients with POAG. Additionally, we sequenced the coding sequence of CYP1B1 gene in 13 independent patients to deep analyze the potential association of hypomorphic CYP1B1 alleles in the pathogenesis of POAG. We detected nine rare variants in 16% of POAG patients studied by NGS. Those rare variants are located in CYP1B1, SIX6, CARD10, MFN1, OPTC, OPTN, and WDR36 glaucoma-related genes. Hypomorphic variants in CYP1B1 and SIX6 genes have been identified in 8% of the total POAG patient assessed. Our findings suggest that NGS could be a valuable tool to clarify the impact of genetic component on adult glaucoma. However, in order to demonstrate the contribution of these rare variants and hypomorphic alleles to glaucoma, segregation and functional studies would be necessary. The identification of new variants and hypomorphic alleles in glaucoma patients will help to configure the genetic identity of these patients, in order to make an early and precise molecular diagnosis.

Causal relationships between Gut microbiota and primary open-angle Glaucoma: A Mendelian randomization and mediation analysis of Glaucoma endophenotypes

Primary open-angle glaucoma (POAG) is a widespread condition responsible for irreversible blindness, and its prevalence is expected to increase substantially in the coming decades. Despite its significance, the exact cause of POAG remains elusive, necessitating a comprehensive exploration of its pathogenesis. Emerging research suggests a potential link between alterations in gut microbiota composition and POAG. However, establishing causality in these associations remains a challenge.In this study, we employed Mendelian randomization (MR) analysis to investigate the potential causal relationships between gut microbiota (GM) and POAG. Significant bacteria taxa were further analyzed with POAG endophenotypes. We utilized data from genome-wide association studies (GWAS) for GM and POAG, as well as for glaucoma endophenotypes, including intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness, vertical cup-to-disc ratio (VCDR), and central corneal thickness (CCT). Univariable, multivariable MR and mediation effect analysis were conducted.Our analysis revealed that certain taxa, including phylum Euryarchaeota, genus Odoribacter, Rumnicoccaceae UCG009, Ruminiclostridium9, unknown genus id.2071, and Eubacterium rectale group, were associated with an increased risk of POAG. On the other hand, family Victivallaceae, Lacchnospiraceae, genus Lachnoclostridium, Oscillospira, Ruminococcaceae UCG011, Alloprevotella, and Faecalibacterium were found to be associated with a decreased risk of POAG. Furthermore, some of these taxa were found to be connected to glaucoma endophenotypes. Through further multivariable MR analysis, it was determined that IOP, VCDR, and CCT might played mediating roles between GM and POAG.In conclusion, this study utilizes MR analysis to elucidate potential causal associations between GM and POAG, providing insights into specific GM taxa that influence POAG risk and related endophenotypes. These findings emphasize the potential role of the gut microbiota in the pathogenesis of POAG and pave the way for future research and therapeutic interventions.

Integrating genetic regulation and single-cell expression with GWAS prioritizes causal genes and cell types for glaucoma

Primary open-angle glaucoma (POAG), characterized by retinal ganglion cell death, is a leading cause of irreversible blindness worldwide. However, its molecular and cellular causes are not well understood. Elevated intraocular pressure (IOP) is a major risk factor, but many patients have normal IOP. Colocalization and Mendelian randomization analysis of >240 POAG and IOP genome-wide association study (GWAS) loci and overlapping expression and splicing quantitative trait loci (e/sQTLs) in 49 GTEx tissues and retina prioritizes causal genes for 60% of loci. These genes are enriched in pathways implicated in extracellular matrix organization, cell adhesion, and vascular development. Analysis of single-nucleus RNA-seq of glaucoma-relevant eye tissues reveals that the POAG and IOP colocalizing genes and genome-wide associations are enriched in specific cell types in the aqueous outflow pathways, retina, optic nerve head, peripapillary sclera, and choroid. This study nominates IOP-dependent and independent regulatory mechanisms, genes, and cell types that may contribute to POAG pathogenesis.

Self-generating electricity system driven by aqueous humor flow and trabecular meshwork contraction motion activated BCKa for glaucoma intraocular pressure treatment.

Primary open-angle glaucoma (POAG) is the most common form of glaucoma and the leading cause of irreversible vision loss and blindness worldwide. Intraocular pressure (IOP) is the only modifiable risk factor, and prompt treatment to lower IOP can effectively slow the rate of vision loss due to glaucoma. Trabecular meshwork (TM) cells can maintain IOP homeostasis by correcting and adjusting the resistance to aqueous humor outflow in response to sustained pressure changes. TM cells' function is reduced, and membrane ion channels are impaired in POAG. The dysfunction of Large conductance Ca2+-activated K+ (BKCa) plays a central role in the pathogenesis of POAG. In this work, we targeted MXene nanoparticles (MXene-RGD) with piezoelectric response to TM cells in a 3D model of glaucoma in vitro as well as in the rabbit Transient Ocular Hypertension (OHT) Model in vivo. MXene-RGD gives the TM electromechanical transfer properties, while the self-enhancing and self-generated electricity properties of the TM are determined by the aqueous humor flow rate and the size of the deformation of the TM. MXene-RGD is nontoxic, as illustrated by a cell toxicity study and histological examination. In a 3D in vitro model of high-pressure glaucoma, whole-cell patch-clamp confirmed that piezoelectric stimulation turns on BKCa, which reduces the volume of the cell. MXene-RGD was injected into the anterior chamber with minimal trauma, i.e., anterior chamber injection, and specifically targeted to TM cells. The OHT model in vivo confirmed the potential IOP-lowering ability of MXene-RGD. We evaluated the ion channels involved in the reduction of IOP by MXene-RGD by pre-treatment with a BKCa channel blocker (iberiotoxin, IbTX) and a voltage-gated Ca2+channel blocker (nifedipine). Quantitative qPCR analysis showed that MXene-RGD inhibited the upregulation of mRNA expression levels of the myofibroblast marker α-smooth muscle actin (α-SMA) and the inflammatory response marker interleukin-6 (IL-6) induced by IOP. Histology confirmed that MXene-RGD attenuated IOP-induced proliferation and collagen production in the TM. Taken together, we present for the first time a minimally invasive surgical approach for targeting TM cells for POAG by utilizing piezoresponse nanomaterials to target BKCa to repair or awaken the ability of TM cells to regulate IOP homeostasis on their own.

Optical Coherence Tomography Angiography Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes

Abstract Purpose: To evaluate and compare optical coherence tomography angiography (OCTA) retinal vasculature measurements in healthy, glaucoma suspect (GS), and glaucoma patients. Methods: One hundred fourteen eyes with good quality OCTA pictures were included from 38 healthy, 38 GS, 38 and primary open-angle glaucoma (POAG) participants. The information on retinal vasculature was summarized as a vessel density map and as vessel density (%), which is the fraction of the flowing vessel area over the total area examined. The superior, inferior, nasal, and temporal quadrants, as well as whole vessel density (wVD) and peripapillary vessel density (ppVD) data taken from the retinal nerve fiber layer, were studied. Global indices of the visual field were correlated with vessel density measurement. Results: Mean vessel density was significantly lower in POAG eyes compared with GSs and healthy eyes (wVD) 45.34% ± 6.64%, 50.06% ± 1.97% and 53.06% ± 2.12%, respectively (P &lt; 0.001), and ppVD 47.42% ± 7.73%, 47.42% ± 7.73% and 56.074% ± 2.71%, respectively (P &lt; 0.001). A linear relationship between vessel density (wVD and ppVD) and global indices of the visual field (mean deviation [MD] and pattern standard deviation [PSD]) shows a significant (P &lt; 0.001) relation. R 2 is 0.35, 0.36, 0.36, and 0.33 for MD and wVD, PSD and wVD, PSD and ppVD, and MD and ppVD, respectively. Conclusions: For distinguishing between healthy and glaucoma eyes, OCTA vessel density demonstrated near similar diagnostic accuracy to visual field tests. These findings imply that OCTA measurements reflect damage to tissues important in the pathogenesis of POAG.

Association of WDR36 polymorphisms with primary open-angle glaucoma

Background: Various genes contribute to the pathophysiology of primary open-angle glaucoma (POAG). The WD repeat domain 36 (WDR36) gene may participate in T cell activation and, hence, in the pathogenesis of POAG. We investigated the association of two WDR36 gene single nucleotide polymorphisms (SNPs) with POAG.&#x0D; Methods: This cross-sectional study recruited patients aged &gt;40 years with POAG and investigated the rs10038177 and rs1971050 SNPs of WDR36 using polymerase chain reaction and direct DNA sequencing. All participants underwent comprehensive ocular examination, visual field assessment using the Swedish Interactive Threshold Algorithm standard 24-2 threshold test, and measurement of peripapillary retinal nerve fiber layer thickness (RNFLT) using spectral domain optical coherence tomography.&#x0D; Results: We enrolled 105 patients with a mean (standard deviation) age of 55.41 (8.56) years and a male-to-female ratio of 56 (53.3%) to 49 (46.7%), most of whom had a diagnosis of POAG for 2 to 5 years (60.0%). Most participants had diabetes (90.5%) but not hypertension (88.6%). There was a significant association of rs10038177 (P&lt;0.05), but not rs1971050 (P&gt;0.05), with family history of glaucoma. The association between rs10038177 and intraocular pressure was significant (P&lt;0.05), but that between rs1971050 and intraocular pressure was not (P&gt;0.05). No significant association was observed between mean cup-to-disc ratio and either SNP (both P&gt;0.05). For rs10038177, a significant association was found only with the RNFLT of the superior quadrant (P&lt;0.05), whereas for rs1971050, a significant association was found with the RNFLT of all four quadrants and average RNFLT (all P&lt;0.05). However, pairwise comparisons revealed no significant differences between genotypes (P&gt;0.05 for all pairwise comparisons). The association of rs10038177 with glaucoma severity was insignificant (P&gt;0.05), and most patients with the TC genotype (71.7%) had moderate severity. There was no significant association between rs1971050 and glaucoma severity (P&gt;0.05).&#x0D; Conclusions: We observed genetic links between some, but not all, characteristics of POAG and the rs10038177 and rs1971050 SNPs of WDR36. Follow-up studies on these and other WDR36 SNPs in populations with different genetic backgrounds are necessary to confirm this genetic association.

Identification and validation of autophagy-related genes in primary open-angle glaucoma

BackgroundAs the most common type of glaucoma, the etiology of primary open-angle glaucoma (POAG) has not been unified. Autophagy may affect the occurrence and development of POAG, while the specific mechanism and target need to be further explored.MethodsThe GSE27276 dataset from the Gene Expression Omnibus (GEO) database and the autophagy gene set from the GeneCards database were selected to screen differentially expressed autophagy-related genes (DEARGs) of POAG. Hub DEARGs were selected by constructing protein-protein interaction (PPI) networks and utilizing GSE138125 dataset. Subsequently, immune cell infiltration analysis, genome-wide association study (GWAS) analysis, gene set enrichment analysis (GSEA) and other analyses were performed on the hub genes. Eventually, animal experiments were performed to verify the mRNA levels of the hub genes by quantitative real time polymerase chain reaction (qRT-PCR).ResultsA total of 67 DEARGs and 2 hub DEARGs, HSPA8 and RPL15, were selected. The hub genes were closely related to the level of immune cell infiltration. GWAS analysis confirmed that the causative regions of the 2 hub genes in glaucoma were on chromosome 11 and chromosome 3, respectively. GSEA illustrated that pathways enriched for highly expressed HSPA8 and RPL15 contained immunity, autophagy, gene expression and energy metabolism-related pathways. qRT-PCR confirmed that the expression of Hspa8 and Rpl15 in the rat POAG model was consistent with the results of bioinformatics analysis.ConclusionsThis study indicated that HSPA8 and RPL15 may affect the progression of POAG by regulating autophagy and provided new ideas for the pathogenesis and treatment of POAG.

Construction of miRNA-mRNA regulatory network indicates potential biomarkers for primary open-angle glaucoma

BackgroundTrabecular meshwork (TM) dysfunction-induced elevation of intraocular pressure has been identified as the main risk factor of irreversible optic nerve injury in Primary open‑angle glaucoma (POAG). Increasing evidences suggest that microRNA (miRNA) plays a vital role in the pathogenesis of POAG. This study aims to construct a miRNA-mRNA regulatory network and identify biomarkers for POAG.MethodsmiRNAs and mRNAs expression profiling of TM samples from controls and POAG patients were assessed through microarray analysis. Target genes of differentially expressed miRNAs (DEmiRNAs) were predicted by miEAA and miRNet. Then GO and KEGG pathway analysis of differentially expressed mRNAs (DEmRNAs) were performed. PPI of top 30 hub genes was identified and miRNA-mRNA network was established by STRING database and Cytoscape software. GSE27276 and GSE105269 datasets were used to verify the expression of hub genes and to predict potential biomarkers in TM and aqueous humor (AH) for POAG, respectively. Finally, GSEA analysis was conducted to estimate the main signaling pathway of POAG pathogenesis.ResultsA total of 29 up-regulated and 7 down-regulated miRNAs, 923 up-regulated and 887 down-regulated mRNAs were identified in TM of POAG compared with controls. Target genes and DEmRNAs were mainly enriched in nitric oxide biosynthetic process, vasopressin-regulated water reabsorption, and so on. Through miRNA-mRNA network construction, top 30 hub genes were regulated by 24 DEmiRNAs. 8 genes were aberrantly expressed in dataset GSE27276. 3 genes (CREB1, CAPZA2, SLC2A3) and 2 miRNAs (miR-106b-5p, miR-15a-5p) were identified as potential biomarkers for POAG in TM and AH, respectively. GSEA analysis revealed that these 3 genes modulated POAG through different pathways.ConclusionIn this study, construction of miRNA-mRNA network and identification of biomarkers provide a novel insight into the pathogenesis, early diagnosis and treatment for POAG.

Gender-specific lncRNA-miRNA-mRNA regulatory network to reveal potential genes for primary open-angle glaucoma

BackgroundInvestigation of biomarkers may facilitate understanding the mechanisms of primary open-angle glaucoma (POAG) and developing therapeutic targets. This study aimed to identify potential genes based on competing endogenous RNA (ceRNA) network for POAG. MethodsBased on long noncoding RNAs (lncRNAs), microRNAs (miRNAs) and messenger RNAs (mRNAs) from the Gene Expression Omnibus (GEO) database, we identified differential expressed lncRNAs (DELs), differential expressed miRNAs (DEMis) and differential expressed mRNAs (DEMs) and then constructed a ceRNA network. Through weighted gene co-expression network analysis (WGCNA), we identified gender-specific genes for gender-associated ceRNA network construction, followed by the protein-protein interaction (PPI) network and functional enrichment analysis to screen hub genes and reveal their functions. The expression levels of hub genes were measured in steroid-induced ocular hypertension (SIOH) mice. ResultsA total of 175 DELs, 727 DEMs and 45 DEMis were screened between control and POAG samples. Seven modules were identified through WGCNA and one module was associated with gender of POAG patients. We discovered 41 gender-specific genes for gender-associated ceRNA construction and then identified 8 genes (NAV3, C1QB, RXRB, P2RY4, ADAM15, VAV3, ZNF207 and TOP1), which were enriched in cell cycle-related pathways and immune-related pathways. C1QB, RXRB, Top1 and ZNF207 were highly interacted with other proteins. The expression levels of NAV3 and C1QB were downregulated in SIOH, while the levels of RXRB, P2RY4, ADAM15, VAV3, ZNF207 and TOP1 were upregulated in SIOH. ConclusionThis study identifies hub genes associated with the pathogenesis of gender-specific POAG and provides potential biomarkers for POAG.

Role of NLRP3 in the immunopathogenesis of neurodegenerative eye diseases

Neurodegenerative eye pathology is one of the leading causes of visual impairment and blindness worldwide. Primary open-angle glaucoma (POAG) belongs to the group of neurodegenerative ophthalmic diseases and is characterized by a permanent or periodic increase in intraocular pressure, followed by development of typical visual field defects, decreased visual acuity and optic nerve atrophy. Recent studies show that local inflammation, triggered by the innate immune system is the first line of defense against the pathogens and tissue destruction products, playing an important role in the POAG pathogenesis. The aim was to study the neurodegenerative ophthalmic disorder in a rabbit model, and to compare the data on distribution of alleles and genotypes of the polymorphic marker rs7525979 of NLRP3 gene in the patients with POAG. At the first stage, we studied the complex tissue samples of the retina/retinal pigment epithelium (TCS/RPE) isolated from the eyes of 14 experimental animals and 7 intact rabbits without eye damage. Neurodegenerative pathology of the eye in rabbits was carried out in the Experimental Center at the Helmholtz National Medical Research Center by a single subretinal injection of 0.01 ml of 0.9% sodium chloride solution. NLRP3 gene expression levels in TCS/RPE samples were evaluated by real-time polymerase chain reaction (PCR-RV). At the second stage, peripheral blood samples were examined in patients who were diagnosed with POAG of various stages, as well as without glaucoma. DNA was isolated from blood samples, which was subsequently analyzed for the polymorphic markers study using PCR-RT technique. According to the results of the study, we noted an increased expression of the NLRP3 gene in the TCS/RPE samples from experimental animals with simulated retinal degeneration. Moreover, an association of alleles and genotypes of the NLRP3 gene was revealed in patients with POAG. The data obtained may be indicative for involvement of NLRP3 inflammasome components in development of neurodegenerative retinal lesions in POAG.

Identification and validation of key biomarkers and potential therapeutic targets for primary open-angle glaucoma.

Primary open-angle glaucoma (POAG) is a prevalent cause of blindness worldwide, resulting in degeneration of retinal ganglion cells and permanent damage to the optic nerve. However, the underlying pathogenetic mechanisms of POAG are currently indistinct, and there has been no effective nonsurgical treatment regimen. The objective of this study is to identify novel biomarkers and potential therapeutic targets for POAG. The mRNA expression microarray datasets GSE27276 and GSE138125, as well as the single-cell high-throughput RNA sequencing (scRNA-seq) dataset GSE148371 were utilized to screen POAG-related differentially expressed genes (DEGs). Functional enrichment analyses, protein-protein interaction (PPI) analysis, and weighted gene co-expression network analysis (WGCNA) of the DEGs were performed. Subsequently, the hub genes were validated at a single-cell level, where trabecular cells were annotated, and the mRNA expression levels of target genes in different cell clusters were analyzed. Immunofluorescence and quantitative real-time PCR (qPCR) were performed for further validation. DEGs analysis identified 43 downregulated and 32 upregulated genes in POAG, which were mainly enriched in immune-related pathways, oxidative stress, and endoplasmic reticulum (ER) stress. PPI networks showed that FN1 and DUSP1 were the central hub nodes, while GPX3 and VAV3 were screened out as hub genes through WGCNA and subsequently validated by qPCR. Finally, FN1, GPX3, and VAV3 were determined to be pivotal core genes via single-cell validation. The relevant biomarkers involved in the pathogenesis of POAG, may serve as potential therapeutic targets. Further studies are necessary to unveil the mechanisms underlying the expression variations of these genes in POAG.

Evaluation of microvascular changes in the retina and choriocapillaris in primary glaucoma and neuromyelitis optica spectrum disorder with optical coherence tomography angiography

BackgroundTo assess quantitatively the microvascular changes in the retina and choroid of healthy eyes, eyes of subjects with primary angle-closure glaucoma (PACG), primary open-angle glaucoma (POAG) and neuromyelitis optica spectrum disorder (NMOSD) using optical coherence tomography angiography (OCTA). MethodsA series of healthy individuals and subjects with PACG, POAG and NMOSD were recruited in this cross-sectional study. OCTA was performed to capture the optic nerve head and macula images and the vessel density (VD) and retinal nerve fiber layer (RNFL) thickness were quantified. The choriocapillary flow density (CFD) was calculated as the percentage of flow area to the whole selected area. ResultsA total of 68 PACG subjects, 25 POAG subjects, 51 NMOSD subjects and 37 healthy controls were enrolled. Significant decreases in peripapillary VD and RNFL thickness were observed in PACG (p < 0.001) and POAG (p < 0.001) eyes and also in NMOSD subjects with an optic neuritis history (p < 0.001) compared with healthy controls. Unaffected eyes in PACG and POAG subjects had lower baseline peripapillary VD than healthy controls (p = 0.002 and p = 0.011, respectively). PACG eyes showed a lower baseline CFD than POAG (p = 0.0027) and the CFD in early and advanced PACG eyes showed a significantly much more decrease than POAG (p = 0.002 and p < 0.001, respectively). ConclusionsThe peripapillary vessel density and RNFL thickness was reduced in glaucomatous and NMOSD eyes compared with healthy controls. PACG eyes showed a lower CFD than POAG and the distinct peripapillary and choriocapillaris microvasculature changes may be correlated to different PACG and POAG pathogenesis.

Analysis of retinal arteriolar and venular parameters in primary open angle glaucoma.

To measure the retinal vessels of primary open angle glaucoma (POAG) patients on spectral domain optical coherence tomography (SD-OCT) with a full-width at half-maximum (FWHM) algorithm to better explore their structural changes in the pathogenesis of POAG. In this retrospective case-control study, the right eyes of 32 patients with POAG and 30 healthy individuals were routinely selected. Images of the supratemporal and infratemporal retinal vessels in the B zones were obtained by SD-OCT, and the edges of the vessels were identified by the FWHM method. The internal and external diameters, wall thickness (WT), wall cross-sectional area (WCSA) and wall-to-lumen ratio (WLR) of the blood vessels were studied. Compared with the healthy control group, the POAG group showed a significantly reduced retinal arteriolar outer diameter (RAOD), retinal arteriolar lumen diameter (RALD) and WSCA in the supratemporal (124.22±12.42 vs 138.32±10.73 µm, 96.09±11.09 vs 108.53±9.89 µm, and 4762.02±913.51 vs 5785.75±1148.28 µm2, respectively, all P<0.05) and infratemporal regions (125.01±15.55 vs 141.57±10.77 µm, 96.27±13.29 vs 110.83±10.99 µm, and 4925.56±1302.88 vs 6087.78±1061.55 µm2, all P<0.05). The arteriolar WT and WLR were not significantly different between the POAG and control groups, nor were the retinal venular outer diameter (RVOD), retinal venular lumen diameter (RVLD) or venular WT in the supratemporal or infratemporal region. There was a positive correlation between the arteriolar parameters and visual function. In POAG, narrowing of the supratemporal and infratemporal arterioles and a significant reduction in the WSCA is observed, while the arteriolar WT and WLR do not change. Among the venular parameters, the external diameter, internal diameter, WT, WLR, and WSCA of the venules are not affected.