Circ_0000615 promotes high glucose-induced human retinal pigment epithelium cell apoptosis, inflammation and oxidative stress via miR-646/YAP1 axis in diabetic retinopathy

YAP in development and disease: Navigating the regulatory landscape from retina to brain

The distinctive role of Yes-associated protein (YAP) in the nervous system has attracted widespread attention. This comprehensive review strategically uses the retina as a vantage point, embarking on an extensive exploration of YAP's multifaceted impact from the retina to the brain in development and pathology. Initially, we explore the crucial roles of YAP in embryonic and cerebral development. Our focus then shifts to retinal development, examining in detail YAP's regulatory influence on the development of retinal pigment epithelium (RPE) and retinal progenitor cells (RPCs), and its significant effects on the hierarchical structure and functionality of the retina. We also investigate the essential contributions of YAP in maintaining retinal homeostasis, highlighting its precise regulation of retinal cell proliferation and survival. In terms of retinal-related diseases, we explore the epigenetic connections and pathophysiological regulation of YAP in diabetic retinopathy (DR), glaucoma, and proliferative vitreoretinopathy (PVR). Lastly, we broaden our exploration from the retina to the brain, emphasizing the research paradigm of "retina: a window to the brain." Special focus is given to the emerging studies on YAP in brain disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD), underlining its potential therapeutic value in neurodegenerative disorders and neuroinflammation.

CircZNF609 inhibits miR-150-5p to promote high glucose-induced damage to retinal microvascular endothelial cells

Hyperglycemia is a key contributor to diabetic macrovascular and ocular complications. It triggers a cascade of cellular damage, particularly in the retinal microvascular endothelial cells (RMECs). However, the underlying molecular mechanisms remain only partially understood. This study hypothesizes that CircZNF609 plays a pivotal role in mediating high glucose-induced damage in RMECs by modulating miR-150-5p and its downstream target genes, thereby affecting cellular survival, apoptosis, and oxidative stress. Gene expression datasets (GSE193974 and GSE160308) and clinical samples were used to investigate the expression levels of CircZNF609 and its interaction with miR-150-5p in the context of diabetic retinopathy (DR). Our results demonstrate that CircZNF609 is upregulated in both peripheral blood stem cells from DR patients and high glucose-stimulated hRMECs. Functional experiments reveal that silencing CircZNF609 improves cell viability, reduces apoptosis, inhibits tube formation, and modulates oxidative stress markers, whereas CircZNF609 overexpression exacerbates these effects. Moreover, miR-150-5p, a microRNA, was found to be negatively regulated by CircZNF609 and downregulated in DR. Its overexpression mitigates high glucose-induced cell injury. Our findings suggest a novel mechanism whereby CircZNF609 exacerbates high glucose-induced endothelial cell damage by sponging miR-150-5p, implicating the CircZNF609/miR-150-5p axis as a potential therapeutic target in diabetic retinopathy.

The Hippo signalling pathway and its impact on eye diseases

The Hippo signalling pathway, an evolutionarily conserved kinase cascade, has been shown to be crucial for cell fate determination, homeostasis and tissue regeneration. Recent experimental and clinical studies have demonstrated that the Hippo signalling pathway is involved in the pathophysiology of ocular diseases. This article provides the first systematic review of studies on the regulatory and functional roles of mammalian Hippo signalling systems in eye diseases. More comprehensive studies on this pathway are required for a better understanding of the pathophysiology of eye diseases and the development of effective therapies.

Classical and Innovative Evidence for Therapeutic Strategies in Retinal Dysfunctions

The human retina is a complex anatomical structure that has no regenerative capacity. The pathogenesis of most retinopathies can be attributed to inflammation, with the activation of the inflammasome protein platform, and to the impact of oxidative stress on the regulation of apoptosis and autophagy/mitophagy in retinal cells. In recent years, new therapeutic approaches to treat retinopathies have been investigated. Experimental data suggest that the secretome of mesenchymal cells could reduce oxidative stress, autophagy, and the apoptosis of retinal cells, and in turn, the secretome of the latter could induce changes in mesenchymal cells. Other studies have evidenced that noncoding (nc)RNAs might be new targets for retinopathy treatment and novel disease biomarkers since a correlation has been found between ncRNA levels and retinopathies. A new field to explore is the interaction observed between the ocular and intestinal microbiota; indeed, recent findings have shown that the alteration of gut microbiota seems to be linked to ocular diseases, suggesting a gut-eye axis. To explore new therapeutical strategies for retinopathies, it is important to use proper models that can mimic the complexity of the retina. In this context, retinal organoids represent a good model for the study of the pathophysiology of the retina.

CircRNA in ocular neovascular diseases: Fundamental mechanism and clinical potential

Ocular neovascular disease (OND), characterized by the aberrant formation of immature blood vessels, is the leading cause of vision impairment and blindness. It is important to find effective ways to diagnose and treat these diseases. Circular RNA (circRNA) is a group of endogenous non-coding RNA that play a crucial role in regulating different biological processes. Due to their close association with ocular disease and angiogenesis, circRNAs have become a hotspot in OND research. In this review, we intensively investigate the possibility of using circRNAs in the management of ONDs. In general, angiogenesis is divided into five phases. On the basis of these five steps, we describe the potential of using circRNAs by introducing how they regulate angiogenesis. Subsequently, the interactions between circRNAs and ONDs, including pterygium, corneal neovascularization, age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity, are analyzed in detail. We also introduce the potential use of circRNAs as OND diagnostic biomarkers. Finally, we summarize the prospects of using circRNAs as a potential strategy in OND management. The gaps in recent research are also pointed out with the purpose of promoting the introduction of circRNAs into clinical applications.

Oxidative Stress and Its Regulation in Diabetic Retinopathy

Diabetic retinopathy is the retinal disease associated with hyperglycemia in patients who suffer from type 1 or type 2 diabetes. It includes maculopathy, involving the central retina and characterized by ischemia and/or edema, and peripheral retinopathy that progresses to a proliferative stage with neovascularization. Approximately 10% of the global population is estimated to suffer from diabetes, and around one in 5 of these individuals have diabetic retinopathy. One of the major effects of hyperglycemia is oxidative stress, the pathological state in which elevated production of reactive oxygen species damages tissues, cells, and macromolecules. The retina is relatively prone to oxidative stress due to its high metabolic activity. This review provides a summary of the role of oxidative stress in diabetic retinopathy, including a description of the retinal cell players and the molecular mechanisms. It discusses pathological processes, including the formation and effects of advanced glycation end-products, the impact of metabolic memory, and involvements of non-coding RNA. The opportunities for the therapeutic blockade of oxidative stress in diabetic retinopathy are also considered.

Circ_0006667 contributes to high glucose-induced retinal pigment epithelial cell dysfunction by mediating miR-7-5p/TGFA axis in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a common complication of diabetes mellitus and it can lead to visual impairment and blindness. The loss of retinal pigment epithelial (RPE) cells is associated with the etiology of DR. Moreover, dysregulated circular RNAs (circRNAs) are implicated in DR progression. Therefore, this project aims to explore the role and potential mechanism of circ_0006667 in DR.

METHODS

RPE cells (ARPE-19) were stimulated with high glucose (33 mM; HG group) for 24 h to establish the DR cell model. Circ_0006667, microRNA-7-5p (miR-7-5p), and transforming growth factor alpha (TGFA) expression was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell viability, proliferation, and apoptosis were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry. CyclinD1, Cleaved-caspase-3, and TGFA protein levels were detected using western blot. Using Circinteractome and starBase analysis, the binding miR-7-5p and circ_0006667 or TGFA was predicted, and then validated using dual-luciferase reporter and RNA Immunoprecipitation (RIP).

RESULTS

Circ_0006667 expression was up-regulated in DR patients and HG-induced ARPE-19 cells. HG stimulation suppressed ARPE-19 cell proliferation and promoted cell apoptosis and inflammation, which were alleviated via circ_0006667 silence. Circ_0006667 acted as a molecular sponge for miR-7-5p, and circ_0006667 absence-mediated protective effects in HG-induced ARPE-19 cells were largely overturned by the interference of miR-7-5p. miR-7-5p directly targeted TGFA, and miR-7-5p overexpression protected ARPE-19 cells from HG-induced dysfunction largely by down-regulating TGFA. Circ_0006667 can up-regulate the expression of TGFA by sponging miR-7-5p in ARPE-19 cells.

CONCLUSION

Circ_0006667 silencing protected ARPE-19 cells from HG-induced dysfunction by mediating miR-7-5p/TGFA axis.

Down-Regulation of circCOL1A2 Suppresses the Dysfunction of Diabetes-Related Retinal Microvascular Endothelial Cells via miR-646/FGF7 Axis

PURPOSE

Diabetic retinopathy (DR), the major complication of diabetes, is the leading cause of vision loss and blindness globally. Altered circular RNAs (circRNAs) expression has been found to be involved in DR process. Hence, this work aimed to explore the role and mechanism of circCOL1A2 in DR.

METHODS

Human retinal microvascular endothelial cells (RMECs) treated with high glucose (HG) were used for functional analysis. Levels of genes and proteins were detected using quantitative real-time polymerase chain reaction and western blotting. In vitro experiments were conducted by transwell, tube formation, CCK-8 assays and ELISA, respectively. The binding interaction between miR-646 and circCOL1A2 or FGF7 (Fibroblast Growth Factor 7) was confirmed using dual-luciferase reporter and RNA immunoprecipitation assays.

RESULTS

CircCOL1A2 was highly expressed in retinal tissues of DR patients and HG-induced RMECs. Then RMECs were exposed to HG treatment to mimic the diabetic conditions in vitro. Functionally, circCOL1A2 knockdown attenuated HG-evoked RMEC migration, proliferation, angiogenesis, blood-retina barrier (BRB) injury and inflammation. Mechanistically, circCOL1A2 functioned as a sponge for miR-646, and miR-646 directly targeted FGF7. Further rescue experiments showed that miR-646 inhibition abated the protective effects of circCOL1A2 knockdown on RMEC function under HG treatment. Besides that, miR-646 was decreased in HG-induced RMECs, re-expression of miR-646 reversed HG-evoked RMEC dysfunction, which was rescued by FGF7 overexpression.

CONCLUSION

CircCOL1A2 silencing can suppress HG-induced migration, proliferation, angiogenesis, BRB injury and inflammation in RMECs through miR-646/FGF7 axis, suggesting the potential involvement of circCOL1A2 in DR process.

circ_0041795 Induces YAP1 Upregulation to Accelerate the Progression of Diabetic Retinopathy through Binding to miR-589-5p

Background

Circular RNAs (circRNAs) are involved in the pathogenesis of many diseases, and circ_0041795 was shown to promote the progression of diabetic retinopathy (DR). The aim of this study was to explore the molecular mechanism of circ_0041795 in DR.

Methods

Human retinal pigment epithelial cells ARPE-19 were treated with high glucose (HG). circ_0041795, miR-589-5p, and Yes-associated protein 1 (YAP1) levels were measured by reverse transcription-quantitative polymerase chain reaction assay. Biological behaviors were examined by Cell Counting Kit-8 assay for cell viability, EdU assay for cell proliferation, flow cytometry for cell apoptosis, and enzyme-linked immunosorbent assay for cell inflammation. Oxidative stress was assessed via the commercial kits. Western blot was performed for analysis of protein expression. The molecular binding was assessed via dual-luciferase reporter assay and pull-down assay.

Results

HG-induced inhibiting effects on cell viability and proliferation but promoting effects on cell apoptosis, inflammation, and oxidative stress were ameliorated by silence of circ_0041795. circ_0041795 was identified to act as a miR-589-5p sponge. The regulation of circ_0041795 in HG-induced cell injury was achieved by inhibiting miR-589-5p. miR-589-5p targeted YAP1 and relieved HG-induced cell dysfunction via downregulating YAP1. circ_0041795 sponged miR-589-5p to regulate YAP1 level and activated the NF-κB pathway through the miR-589-5p/YAP1 axis.

Conclusion

All these results elucidated that circ_0041795 facilitated the development of DR by inducing miR-589-5p-mediated YAP1 upregulation.

The Role of H2S Regulating NLRP3 Inflammasome in Diabetes

Nucleotide-binding oligomeric domain (NOD)-like receptor protein 3 (NLRP3) is a recently discovered cytoplasmic multiprotein complex involved in inflammation. The NLRP3 inflammasome contains NLRP3, apoptosis-related specific protein (ASC) and precursor caspase-1. The NLRP3 inflammasome is involved in many diseases, including diabetes. H₂S is a harmful gas with a rotten egg smell. Recently, it has been identified as the third gas signal molecule after nitric oxide and carbon monoxide. It has many biological functions and plays an important role in many diseases, including diabetes. In recent years, it has been reported that H₂S regulation of the NLRP3 inflammasome contributes to a variety of diseases. However, the mechanism has not been fully understood. In this review, we summarized the recent role and mechanism of H₂S in regulating the NLRP3 inflammasome in diabetes, in order to provide a theoretical basis for future research.

miRNA, lncRNA and circRNA: Targeted Molecules Full of Therapeutic Prospects in the Development of Diabetic Retinopathy

Diabetic retinopathy (DR) is a common diabetic complication and the main cause of blindness worldwide, which seriously affects the quality of life of patients. Studies have shown that noncoding RNA (ncRNA) has distinct differentiated expression in DR and plays an important role in the occurrence and development of DR. ncRNAs represented by microRNAs (miRNAs), lncRNAs (lncRNAs), and circRNAs (circRNAs) have been shown to be widely involved in the regulation of gene expression and affect multiple biological processes of retinopathy. This article will review three RNAs related to the occurrence and development of DR on the basis of previous studies (especially their effects on retinal microangiopathy, retinal pigment epithelial cells, and retinal nerve cells) and discuss their underlying mechanisms and connections. Overall, this review will help us better understand the role of ncRNAs in the occurrence and development of DR and provide ideas for exploring potential therapeutic directions and targets.