Pathogenesis and prospects for therapeutic clinical application of noncoding RNAs in glaucoma: Systematic perspectives

CircRNA expression profiles and regulatory networks in the vitreous humor of people with high myopia

Myopia is a global health and economic issue. Circular RNAs (circRNAs) have been shown to play an important role in the pathogenesis of many ocular diseases. We first evaluated the circRNA profiles and possible roles in vitreous humor samples of individuals with high myopia by a competitive endogenous RNA (ceRNA) array. Vitreous humor samples were collected from 15 high myopic (5 for ceRNA array, and 10 for qPCR) and 15 control eyes (5 for ceRNA array, and 10 for qPCR) with idiopathic epiretinal membrane (ERM) and macular hole (MH). 486 circRNAs (339 upregulated and 147 downregulated) and 264 mRNAs (202 upregulated and 62 downregulated) were differentially expressed between the high myopia and control groups. The expression of hsa_circ_0033079 (hsa-circDicer1), hsa_circ_0029989 (hsa-circNbea), hsa_circ_0019072 (hsa-circPank1) and hsa_circ_0089716 (hsa-circEhmt1) were validated by qPCR. Pearson analysis and multivariate regression analysis showed positive and significant correlations for axial length with hsa-circNbea and hsa-circPank1. KEGG analysis showed that the target genes of circRNAs were enriched in the mTOR, insulin, cAMP, and VEGF signaling pathways. GO analysis indicated that circRNAs mainly targeted transcription, cytoplasm, and protein binding. CircRNA-associated ceRNA network analysis and PPI network analysis identified several critical genes for myopia. The expression of circNbea, circPank1, miR-145-5p, miR-204-5p, Nras, Itpr1 were validated by qPCR in the sclera of form-deprivation myopia (FDM) mice model. CircPank1/miR-145-5p/NRAS and circNbea/miR-204-5p/ITPR1 were identified and may be important in the progression of myopia. Our findings suggest that circRNAs may contribute to the pathogenesis of myopia and may serve as potential biomarkers.

Potential roles of lncRNA MALAT1-miRNA interactions in ocular diseases

Long non-coding RNAs (lncRNAs) are non-protein coding transcripts that are longer than 200 nucleotides in length. LncRNAs are implicated in gene expression at the transcriptional, translational, and epigenetic levels, and thereby impact different cellular processes including cell proliferation, migration, apoptosis, angiogenesis, and immune response. In recent years, numerous studies have demonstrated the significant contribution of lncRNAs to the pathogenesis and progression of various diseases, such as stroke, heart disease, and cancer. Further investigations have shown that lncRNAs have altered expression patterns in ocular tissues and cell lines during pathological conditions. The pathogenesis of various ocular diseases, including glaucoma, cataract, corneal diseases, proliferative vitreoretinopathy, diabetic retinopathy, and retinoblastoma, is influenced by the involvement of specific lncRNAs which play a critical role in the development and progression of these diseases. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a well-researched lncRNA in the context of ocular diseases, which has been shown to exert its biological effects through several signaling pathways and downstream targets. The present review provides a comprehensive summary of the molecular mechanisms underlying the biological functions and roles of MALAT1 in ocular diseases.

miRNA Studies in Glaucoma: A Comprehensive Review of Current Knowledge and Future Perspectives

Glaucoma, a neurodegenerative disorder that leads to irreversible blindness, remains a challenge because of its complex nature. MicroRNAs (miRNAs) are crucial regulators of gene expression and are associated with glaucoma and other diseases. We aimed to review and discuss the advantages and disadvantages of miRNA-focused molecular studies in glaucoma through discussing their potential as biomarkers for early detection and diagnosis; offering insights into molecular pathways and mechanisms; and discussing their potential utility with respect to personalized medicine, their therapeutic potential, and non-invasive monitoring. Limitations, such as variability, small sample sizes, sample specificity, and limited accessibility to ocular tissues, are also addressed, underscoring the need for robust protocols and collaboration. Reproducibility and validation are crucial to establish the credibility of miRNA research findings, and the integration of bioinformatics tools for miRNA database creation is a valuable component of a comprehensive approach to investigate miRNA aberrations in patients with glaucoma. Overall, miRNA research in glaucoma has provided significant insights into the molecular mechanisms of the disease, offering potential biomarkers, diagnostic tools, and therapeutic targets. However, addressing challenges such as variability and limited tissue accessibility is essential, and further investigations and validation will contribute to a deeper understanding of the functional significance of miRNAs in glaucoma.

The 3' UTR polymorphisms rs3742330 in DICER1 and rs10719 in DROSHA genes are not associated with primary open-angle and angle-closure glaucoma: As case-control study

AIM

In a retrospective and exploratory case-control study, we examined the genetic association of two common polymorphisms in the 3' untranslated region (UTR) of DICER1 (rs3742330) and DROSHA (rs10719) genes in primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and its related clinical phenotypes in a Saudi cohort.

METHODS

DNA genotyping was performed using TaqMan real-time PCR assays in 500 participants, including 152 POAG, 102 PACG, and 246 non-glaucomatous controls. Statistical analyses were performed to examine the association(s).

RESULTS

Allele and genotype frequency of rs3742330 and rs10719 did not vary significantly in POAG and PACG compared to controls. No significant deviation was observed from Hardy-Weinberg Equilibrium (p > 0.05). Gender stratification revealed no significant allelic/genotype association with glaucoma types. Also, these polymorphisms showed no significant genotype effect on clinical markers such as intraocular pressure, cup/disc ratio, and the number of antiglaucoma medications. Logistic regression showed no effect of age, sex, rs3742330, and rs10719 genotypes on the risk of disease outcome. We also examined a combined allelic effect of rs3742330 (A>G) and rs10719 (A>G). However, none of the allelic combinations significantly affected POAG and PACG.

CONCLUSIONS

The 3' UTR polymorphisms rs3742330 and rs10719 of DICER1 and DROSHA genes are not associated with POAG and PACG or its related glaucoma indices in this Middle-Eastern cohort of Saudi Arab ethnicity. However, there is a need to validate the results on a broader population and other ethnicities.

Translocator protein 18 kDa regulates retinal neuron apoptosis and pyroptosis in glaucoma

Glaucoma is the leading cause of blindness worldwide. However, our insufficient understanding of the pathogenesis of glaucoma has limited the development of effective treatments. Because recent research has highlighted the importance of non-coding RNAs (ncRNAs) in various diseases, we investigated their roles in glaucoma. Specifically, we detected expression changes of ncRNAs in cell and animal models of acute glaucoma. Further analysis revealed that the Ier2/miR-1839/TSPO axis was critical to cell loss and retinal damage. The knockdown of Ier2, the overexpression of miR-1839, and the silencing of TSPO effectively prevented retinal damage and cell loss. Furthermore, we found that the Ier2/miR-1839/TSPO axis regulated the pyroptosis and apoptosis of retinal neurons through the NLRP3/caspase1/GSDMD, cleaved-caspase3 pathways. In addition to high expression in the retina, TSPO expression was found to be significantly higher in the dorsal lateral geniculate nucleus (DLG) of the brain in the pathologically high intraocular pressure (ph-IOP) rat model, as well as in the peripheral blood mononuclear cells (PBMCs) of glaucoma patients with high IOP. These results indicate that TSPO, which is regulated by Ier2/miR-1839, plays an important role in the pathogenesis of glaucoma, and this study provides a theoretical basis and a new target for the diagnosis and treatment of glaucoma.

Twenty Novel MicroRNAs in the Aqueous Humor of Pseudoexfoliation Glaucoma Patients

The microRNAs (miRNAs) are short non-coding RNAs (19-25 nt) that regulate the level of gene expression at the post-transcriptional stage. Altered miRNAs expression can lead to the development of various diseases, e.g., pseudoexfoliation glaucoma (PEXG). In this study, we assessed the levels of miRNA expression in the aqueous humor of PEXG patients using the expression microarray method. Twenty new miRNA molecules have been selected as having the potential to be associated with the development or progression of PEXG. Ten miRNAs were downregulated in PEXG (hsa-miR-95-5p, hsa-miR-515-3p, hsa-mir-802, hsa-miR-1205, hsa-miR-3660, hsa-mir-3683, hsa -mir-3936, hsa-miR-4774-5p, hsa-miR-6509-3p, hsa-miR-7843-3p) and ten miRNAs were upregulated in PEXG (hsa-miR-202 -3p, hsa-miR-3622a-3p, hsa-mir-4329, hsa-miR-4524a-3p, hsa-miR-4655-5p, hsa-mir-6071, hsa-mir-6723-5p, hsa-miR-6847-5p, hsa-miR-8074, and hsa-miR-8083). Functional analysis and enrichment analysis showed that the mechanisms that can be regulated by these miRNAs are: extracellular matrix (ECM) imbalance, cell apoptosis (possibly retinal ganglion cells (RGCs)), autophagy, and elevated calcium cation levels. Nevertheless, the exact molecular basis of PEXG is unknown and further research is required on this topic.

Profiling the miRNA from Exosomes of Non-Pigmented Ciliary Epithelium-Derived Identifies Key Gene Targets Relevant to Primary Open-Angle Glaucoma

Oxidative stress (OS) on tissues is a major pathological insult leading to elevated intraocular pressure (IOP) and primary open-angle glaucoma (POAG). Aqueous humor (AH) produced by the non-pigmentary ciliary epithelium (NPCE) drains out via the trabecular meshwork (TM) outflow pathway in the anterior chamber. The exosomes are major constituents of AH, and exosomes can modulate the signaling events, as well as the responses of their target TM tissue. Despite the presence of molecular mechanisms to negate OS, oxidative damage directly, as well as indirectly, influences TM health, AH drainage, and IOP. We proposed that the expression of microRNA (miRNAs) carried by exosomes in the AH can be affected by OS, and this can modulate the pathways in target cells. To assess this, we subjected NPCE to acute and chronic OS (A-OS and C-OS), enriched miRNAs, performed miRNA microarray chip analyses, and miRNA-based gene targeting pathway prediction analysis. We found that various miRNA families, including miR27, miR199, miR23, miR130b, and miR200, changed significantly. Based on pathway prediction analysis, we found that these miRNAs can regulate the genes including Nrf2, Keap1, GSK3B, and serine/threonine-protein phosphatase2A (PP2A). We propose that OS on the NPCE exosomal miRNA cargo can modulate the functionality of the TM tissue.

Integrated analysis of long non-coding RNAs and mRNAs associated with glaucoma in vitro

INTRODUCTION

In recent years, the biological functions and important roles of long non-coding RNAs (lncRNAs) have been widely reported in many diseases. Although glaucoma is the leading cause of blindness worldwide, the specific mechanisms of lncRNAs in the pathogenesis and progression of glaucoma remain unclear. Our research aims to elucidate the differentially expressed lncRNAs and mRNAs in glaucoma and to provide a basis for further exploration of the specific mechanism of action of lncRNAs in the progression of glaucoma.

METHODS

We performed RNA sequencing on samples from a pressurized model of R28 cells and performed bioinformatics analyses on the sequencing results. The expression consistency of lncRNAs in clinical samples from patients with glaucoma or cataracts was detected using real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

RNA sequencing results showed that lncRNAs in cluster 5 were upregulated with increasing stress after typing all significantly altered lncRNAs using k-means in a cellular stress model. KEGG analysis indicated that they were associated with neurodegenerative diseases. Differentially expressed lncRNAs were verified by RT-qPCR, and the lncRNA expression levels of AC120246.2 and XLOC_006247 were significantly higher in the aqueous humor (AH) of patients with glaucoma than in those with cataracts. For LOC102551819, there was almost no expression in the AH and trabecular meshwork in patients with glaucoma but high expression was observed in the iris.

CONCLUSION

Our research proposes potential diagnostic or intervention targets for clinical applications as well as a theoretical basis for more in-depth research on the function of lncRNAs in glaucoma.

Small Nucleolar RNAs in Pseudoexfoliation Glaucoma

Small nucleolar RNAs (snoRNAs) are small non-coding regulatory RNAs that have been investigated extensively in recent years. However, the relationship between snoRNA and glaucoma is still unknown. This study aims to analyze the levels of snoRNA expression in the aqueous humor (AH) of patients with pseudoexfoliation glaucoma (PEXG) compared to a control group and identify hypothetical snoRNA-dependent mechanisms contributing to PEXG. The AH was obtained from eighteen Caucasian patients, comprising nine PEXG and nine age-matched control patients. RNA was isolated, and a microarray system was used to determine the snoRNA expression profiles. Functional and enrichment analyses were performed. We identified seven snoRNAs, SNORD73B, SNORD58A, SNORD56, SNORA77, SNORA72, SNORA64, and SNORA32, in the AH of the PEXG and control group patients. Five snoRNAs showed statistically significantly lower expression in the PEXG group, and two snoRNAs had statistically significantly higher expression in the PEXG group compared to the control group. In addition, we identified two factors-CACNB3 for SNORA64 and TMEM63C for SNORA32, similar to PEX-related genes (CACNA1A and TMEM136). The enrichment analysis for four genes targeted by snoRNAs revealed possible mechanisms associated with glaucoma and/or PEX, but the direct role of snoRNAs in these biological processes was not proven.

Polymorphism rs3742330 in microRNA Biogenesis Gene DICER1 Is Associated with Pseudoexfoliation Glaucoma in Saudi Cohort

We investigated the association between DICER1 (rs3742330) and DROSHA (rs10719) polymorphisms and pseudoexfoliation glaucoma (PXG) and related clinical phenotypes in a Saudi cohort. In a retrospective case-control study, TaqMan real-time, PCR-based genotyping was performed in 340 participants with 246 controls and 94 PXG cases. The minor (G) allele frequency of rs3742330 in PXG (0.03) was significantly different from that in the controls (0.08) and protective against PXG (odds ratio (OR) = 0.38, 95% confidence interval (CI) = 0.16–0.92), p = 0.017). Similarly, the rs3742330 genotypes showed a significant protective association with PXG in dominant (p = 0.019, OR = 0.38, 95% CI = 0.15–0.92), over-dominant (p = 0.024, OR = 0.39, 95% CI = 0.16–0.95), and log-additive models (p = 0.017, OR = 0.38, 95% CI = 0.16–0.92). However, none remained significant after an adjustment for age, sex, and multiple testing. Rs10719 in DROSHA did not show any significant allelic or genotype association with PXG. However, a protective effect of the GA haplotype in DICER1 and DROSHA and PXG (p = 0.034) was observed. Both polymorphisms showed no significant effect on intraocular pressure and the cup–disk ratio. In conclusion, we report a significant genetic association between variant rs3742330 in DICER1, a gene involved in miRNA biogenesis, and PXG. Further investigation in a larger group of patients of different ethnicities and functional studies are warranted to replicate and validate its potential role in PXG.