Circ_0084043 Facilitates High Glucose-Induced Retinal Pigment Epithelial Cell Injury by Activating miR-128-3p/TXNIP-Mediated Wnt/β-Catenin Signaling Pathway

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.

Role of Lnc-RNAs in the Pathogenesis and Development of Diabetic Retinopathy

Important advances in diabetic retinopathy (DR) research and management have occurred in the last few years. Neurodegenerative changes before the onset of microvascular alterations have been well established. So, new strategies are required for earlier and more effective treatment of DR, which still is the first cause of blindness in working age. We describe herein gene regulation through Lnc-RNAs as an interesting subject related to DR. Long non-coding RNAs (Lnc-RNAs) are non-protein-coding transcripts larger than 200 nucleotides. Lnc-RNAs regulate gene expression and protein formation at the epigenetic, transcriptional, and translational levels and can impact cell proliferation, apoptosis, immune response, and oxidative stress. These changes are known to take part in the mechanism of DR. Recent investigations pointed out that Lnc-RNAs might play a role in retinopathy development as Metastasis-Associated Lung Adenocarcinoma Transcript (Lnc-MALAT1), Maternally expressed gene 3 (Lnc-MEG3), myocardial-infarction-associated transcript (Lnc-MIAT), Lnc-RNA H19, Lnc-RNA HOTAIR, Lnc-RNA ANRIL B-Raf proto-oncogene (Lnc-RNA BANCR), small nucleolar RNA host gene 16 (Lnc-RNA SNHG16) and others. Several molecular pathways are impacted. Some of them play a role in DR pathophysiology, including the PI3K-Akt signaling axis, NAD-dependent deacetylase sirtuin-1 (Sirti1), p38 mitogen-activated protein kinase (P38/mapk), transforming growth factor beta signaling (TGF-β) and nuclear factor erythroid 2-related factor 2 (Nrf2). The way Lnc-RNAs affect diabetic retinopathy is a question of great relevance. Performing a more in-depth analysis seems to be crucial for researchers if they want to target Lnc-RNAs. New knowledge on gene regulation and biomarkers will enable investigators to develop more specialized therapies for diabetic retinopathy, particularly in the current growing context of precision medicine.

Circular RNA circADAM9 Promotes Inflammation, Oxidative Stress, and Fibrosis of Human Mesangial Cells via the Keap1-Nrf2 Pathway in Diabetic Nephropathy

OBJECTIVE

Circular RNAs (circRNAs) have been discovered as potential biomarkers for diabetic nephropathy (DN). In this study, the potential roles of circADAM9 in high glucose (HG)-induced cell injury of human mesangial cells (HMCs) were investigated, and the underlying mechanism was elucidated.

METHODS

DN cell model in vitro was simulated by HG treatment of HMCs. Endogenous expressions of circADAM9, miR-545-3p, and ubiquitin-specific protease 15 (USP15) were determined by real-time polymerase chain reaction. Cell proliferation and migration were evaluated using Cell Counting Kit-8 and wound healing assays. The inflammatory response was assessed by enzyme-linked immunosorbent assay. Oxidative stress was examined using commercially available kits. Dual-luciferase reporter and RNA pull-down assays were conducted to confirm the interaction among circADAM9, miR-545-3p, and USP15.

RESULTS

CircADAM9 was upregulated in DN samples and HG-treated HMCs, while its downregulation inhibited cell proliferation, inflammation, fibrosis, and oxidative stress. Further investigation revealed that circADAM9 exerted this influence by targeting the miR-545-3p/USP15 axis, thereby regulating the KELCH-like ECh-associated protein 1/nuclear factor erythroid 2 related factor 2 (Keap1/Nrf2) pathway. MiR-545-3p knockdown or USP15 overexpression reversed the effect of circADAM9 silencing in HG-induced HMCs.

CONCLUSION

These results indicate that the circADAM9/miR-545-3p/USP15/Keap1/Nrf2 signaling axis is critical for HG-induced cell injury in HMCs and might represent a novel therapeutic target for DN treatment.

Noncoding RNAs Are Promising Therapeutic Targets for Diabetic Retinopathy: An Updated Review (2017-2022)

Diabetic retinopathy (DR) is the most common complication of diabetes. It is also the main cause of blindness caused by multicellular damage involving retinal endothelial cells, ganglial cells, and pigment epithelial cells in adults worldwide. Currently available drugs for DR do not meet the clinical needs; thus, new therapeutic targets are warranted. Noncoding RNAs (ncRNAs), a new type of biomarkers, have attracted increased attention in recent years owing to their crucial role in the occurrence and development of DR. NcRNAs mainly include microRNAs, long noncoding RNAs, and circular RNAs, all of which regulate gene and protein expression, as well as multiple biological processes in DR. NcRNAs, can regulate the damage caused by various retinal cells; abnormal changes in the aqueous humor, exosomes, blood, tears, and the formation of new blood vessels. This study reviews the different sources of the three ncRNAs-microRNAs, long noncoding RNAs, and circular RNAs-involved in the pathogenesis of DR and the related drug development progress. Overall, this review improves our understanding of the role of ncRNAs in various retinal cells and offers therapeutic directions and targets for DR treatment.

Thioredoxin-interacting protein in diabetic retinal neurodegeneration: A novel potential therapeutic target for diabetic retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes mellitus and has been considered a microvascular disease for a long time. However, recent evidence suggests that diabetic retinal neurodegeneration (DRN), which manifests as neuronal apoptosis, a decrease in optic nerve axons, and reactive gliosis, occurs prior to retinal microvascular alterations. Thioredoxin-interacting protein (TXNIP) is an endogenous inhibitor of thioredoxin (Trx), and it acts by inhibiting its reducing capacity, thereby promoting cellular oxidative stress. In addition, it participates in regulating multiple signaling pathways as a member of the α-arrestin family of proteins. Accumulating evidence suggests that TXNIP is upregulated in diabetes and plays a pivotal role in the pathophysiological process of DR. In this review, we summarized the role of TXNIP in DRN, aiming to provide evidence for DR treatment in the future.

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.

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.