Diabetic Retinopathy, lncRNAs, and Inflammation: A Dynamic, Interconnected Network

Genetic association of diabetic retinopathy with long noncoding RNA CDKN2B-AS1 gene polymorphism

AIM

We attempted to test the influences of cyclin dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) gene polymorphisms on the susceptibility to Diabetic retinopathy (DR).

METHODS

Five single-nucleotide polymorphisms (SNPs) of the CDKN2B-AS1 gene, rs564398, rs1333048, rs1537373, rs2151280, and rs8181047 were examined in 280 DR cases and 455 DR-free diabetic controls.

RESULTS

Among these loci tested, we demonstrated that diabetic carriers of at least one polymorphic allele (G) of rs2151280 (AG and GG; AOR, 1.613; 95% CI, 1.040-2.501; p = 0.033) are more susceptible to proliferative DR but not non-proliferative DR. This genetic association with the risk of developing proliferative DR was further strengthened in homozygotes for the polymorphic allele (G) of rs2151280 (GG; AOR, 2.194; 95% CI, 1.117-4.308; p = 0.023). We detected a significant association of the polymorphic allele (G) of rs2151280 with proliferative DR patients (OR, 1.503; 95% CI, 1.112-2.033; p = 0.008) but not with the entire DR or non-proliferative DR group. Moreover, as compared to those who do not possess the polymorphic allele of rs2151280 (AA), DR patients carrying at least one polymorphic allele of rs2151280 (AG + GG) exhibited a lower glomerular filtration rate and HDL cholesterol level, revealing a promotive role of rs2151280 in renal and cardiovascular complications of diabetes.

CONCLUSION

Taken together, our findings implicate an impact of CDKN2B-AS1 gene polymorphisms on the progression of DR.

Mitochondrial Genome-Encoded Long Noncoding RNA Cytochrome B (LncCytB) and Mitochondrial Ribonucleases in Diabetic Retinopathy

AIM

Hyperglycemia damages mitochondria and downregulates transcription of mtDNA-encoded genes and the long noncoding RNA LncCytB, causing mitochondrial genomic instability. The genes encoded by mtDNA are transcribed as large polycistronic transcripts, and the 5' ends of precursor tRNAs are processed by mitochondrial-targeted ribonuclease P (MRPPs). Our aim was to investigate the role of MRPP1 in the downregulation of LncCytB in diabetic retinopathy.

METHODS

Using human retinal endothelial cells incubated in 20 mM D-glucose for 96 h, the gene expression and mitochondrial localization (immunofluorescence) of MRPP1 and the interaction between MRPP1 and LncCytB (determined by RNA-FISH and RNA immunoprecipitation) were quantified. The results were confirmed in retinal microvessels from streptozotocin-induced diabetic mice and from human donors with documented diabetic retinopathy.

RESULTS

Compared to normal glucose, high glucose decreased mRNA and mitochondrial localization of MRPP1 and its interaction with LncCytB. While MRPP1 overexpression prevented glucose-induced decrease in MRPP1-LncCytB interaction, LncCytB expression and mitochondrial damage (reduction in protective nucleoids in mtDNA), MRPP1-siRNA further worsened them. Similar results were obtained from retinal microvessels from diabetic mice and from human donors with diabetic retinopathy.

CONCLUSIONS

Downregulation of MRPP1 in diabetes suppresses LncCytB transcription, resulting in mitochondrial functional and genomic instability, ultimately leading to the development of diabetic retinopathy. Thus, preventing MRPP1 downregulation has the potential to inhibit retinopathy and prevent the fear of vision loss in diabetic patients.

Lnc-216 regulates the miR-143-5p /MMP2 signaling axis aggravates retinal endothelial cell dysfunction

PURPOSE

Diabetic retinopathy (DR) is a serious retinal vascular disease that affects many individuals in their prime working years. The present research aimed at whether and how LOC681216 (LNC-216) is involved in retinal vascular dysfunction under diabetic conditions.

METHODS

Rat retinal microvascular endothelial cells (RRMECs) treated with high glucose (HG) were used for functional analysis. Gene expression analysis was conducted using the Clariom D Affymetrix platform. The wound healing, transwell, and vascular tube formation assays were used to identify the migration, invasion, and tube formation capability of RRMECs. The dual-luciferase reporter confirmed the binding interaction between miR-143-5p and LNC-216 or matrix metallopeptidase 2 (MMP2).

RESULTS

Lnc-216 was upregulated in RRMECs treated with HG. Lnc-216 knockdown markedly suppressed the tube formation, cell migration, and wound healing of cultured RRMECs under HG conditions. Mechanistically, Lnc-216 acted as a miR-143-5p sponge to affect the biological activity of miR-143-5p, which led to increased expression of matrix metallopeptidase 2 (MMP2).

CONCLUSIONS

Lnc-216 attenuates diabetic retinal vascular dysfunction through the miR-143-5p/MMP2 axis, providing a potential therapeutic strategy for DR.

The impact of sestrin2 on reactive oxygen species in diabetic retinopathy

Diabetic retinopathy (DR) is a significant complication of diabetes that often leads to blindness, impacting Müller cells, the primary retinal macroglia involved in DR pathogenesis. Reactive oxygen species (ROS) play a crucial role in the development of DR. The objective of this study was to investigate the involvement of sestrin2 in DR using a high-glucose (HG)-induced Müller cell model and assessing cell proliferation with 5-ethynyl-2-deoxyuridine (EdU) labeling. Following this, sestrin2 was upregulated in Müller cells to investigate its effects on ROS, tube formation, and inflammation both in vitro and in vivo, as well as its interaction with the nuclear factor erythroid2-related factor 2 (Nrf2) signaling pathway. The findings demonstrated a gradual increase in the number of EdU-positive cells over time, with a subsequent decrease after 72 h of exposure to high glucose levels. Additionally, the expression of sestrin2 exhibited a progressive increase over time, followed by a decrease at 72 h. The rh-sestrin2 treatment suppressed the injury of Müller cells, decreased ROS level, and inhibited the tube formation. Rh-sestrin2 treatment enhanced the expression of sestrin2, Nrf2, heme oxygenase-1 (HO-1), and glutamine synthetase (GS); however, the ML385 treatment reversed the protective effect of rh-sestrin2. Finally, we evaluated the effect of sestrin2 in a DR rat model. Sestrin2 overexpression treatment improved the pathological injury of retina and attenuated the oxidative damage and inflammatory reaction. Our results highlighted the inhibitory effect of sestrin2 in the damage of retina, thus presenting a novel therapeutic sight for DR.

Multiplatform tear proteomic profiling reveals novel non-invasive biomarkers for diabetic retinopathy

OBJECTIVES

To investigate a comprehensive proteomic profile of the tear fluid in patients with diabetic retinopathy (DR) and further define non-invasive biomarkers.

METHODS

A cross-sectional, multicentre study that includes 46 patients with DR, 28 patients with diabetes mellitus (DM), and 30 healthy controls (HC). Tear samples were collected with Schirmer strips. As for the discovery set, data-independent acquisition mass spectrometry was used to characterize the tear proteomic profile. Differentially expressed proteins between groups were identified, with gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes enrichment analysis further developed. Classifying performance of biomarkers for distinguishing DR from DM was compared by the combination of three machine-learning algorithms. The selected biomarker panel was tested in the validation cohort using parallel reaction monitoring mass spectrometry.

RESULTS

Among 3364 proteins quantified, 235 and 88 differentially expressed proteins were identified for DR when compared to HC and DM, respectively, which were fundamentally related to retina homeostasis, inflammation and immunity, oxidative stress, angiogenesis and coagulation, metabolism, and cellular adhesion processes. The biomarker panel consisting of NAD-dependent protein deacetylase sirtuin-2 (SIR2), amine oxidase [flavin-containing] B (AOFB), and U8 snoRNA-decapping enzyme (NUD16) exhibited the best diagnostic performance in discriminating DR from DM, with AUCs of 0.933 and 0.881 in the discovery and validation set, respectively.

CONCLUSIONS

Tear protein dysregulation is comprehensively revealed to be associated with DR onset. The combination of tear SIR2, AOFB, and NUD16 can be a novel potential approach for non-invasive detection or pre-screening of DR.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry Identifier: ChiCTR2100054263. https://www.chictr.org.cn/showproj.html?proj=143177 . Date of registration: 2021/12/12.

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.

Upregulation of PCED1B-AS1 in proliferative diabetic retinopathy and its involvement in retinal vascular endothelial cell proliferation

BACKGROUND

This study was to assess the diagnostic value of PCED1B-AS1 for proliferative diabetic retinopathy (PDR) and investigate the involvement of PCED1B-AS1 in PDR.

METHODS

The vitreous and blood specimens from 37 subjects with PDR and 21 non-diabetics were examined by reverse transcription quantitative PCR to determine the PCED1B-AS1 level. The two groups were age- and gender-matched. Receiver operating characteristic (ROC) curves were plotted to visually illustrate the diagnostic ability of PCED1B-AS1. Human retinal Müller glial cells were studied by ELISA. Proliferation and migration of human retinal microvascular endothelial cells (HRMECs) were assessed in vitro.

RESULTS

Significant increases of PCED1B-AS1 levels were observed in the vitreous samples and CD34 + VEGFR-2 + cells from blood samples of diabetic subjects with PDR, compared with those of non-diabetics. The ROC curve based on the vitreous PCED1B-AS1 levels revealed an AUC of 0.812, while the ROC curve based on the PCED1B-AS1 levels in CD34 + VEGFR-2 + cells from blood samples revealed an AUC of 0.870. In Müller cell cultures, PCED1B-AS1 siRNA significantly attenuated VEGF and MCP-1 upregulation which were induced by CoCl₂ and TNF-α. Additionally, PCED1B-AS1 siRNA attenuated VEGF-induced proliferation and migration in HRMECs.

CONCLUSION

This study revealed the potential of PCED1B-AS1 as a diagnostic biomarker for PDR. In vitro data point to the anti-angiogenic and anti-proliferation effects of PCED1B-AS1.

Redoxisome and diabetic retinopathy: Pathophysiology and therapeutic interventions

Diabetic retinopathy (DR) is a chronic microvascular complication of diabetes mellitus (DM). It is a worldwide growing epidemic disease considered to be the leading cause of vision-loss and blindness in people with DM. Redox reactions occurring at the extra- and intracellular levels are essential for the maintenance of cellular homeostasis. Dysregulation of redox homeostasis are implicated in the onset and development of DR. Thioredoxin1 (TRX1) and Thioredoxin2 (TRX2) are cytoplasmic and mitochondrially localized antioxidant proteins ubiquitously expressed in various cells and control cellular reactive oxygen species (ROS) by reducing the disulfides into thiol groups. Thioredoxin-interacting protein (TXNIP) binds to TRX system and inhibits the active reduced form of TRX through disulfide exchange reaction. Recent studies indicate the association of TRX/TXNIP with redox signal transduction pathways including activation of Nod-like receptor pyrin domain containing protein-3 (NLRP3) inflammasome, apoptosis, autophagy/mitophagy, epigenetic modifications in a redox-dependent manner. Thus, it is important to gain a more in-depth understanding about the cellular and molecular mechanisms that links redoxisome and ER/Mitochondrial dysfunction to drive the progression of DR. The purpose of this review is to provide a mechanistic understanding of the complex molecular mechanisms and pathophysiological roles associated with redoxisome, the TRX/TXNIP redox signaling complex under oxidative stress in the development of DR. Also, the molecular targets of FDA approved drugs and clinical trials in addition to effective antioxidant strategies for the treatment of diabetic retinopathy are reviewed.

Putative Biomarkers in Tears for Diabetic Retinopathy Diagnosis

Purpose

Tear fluid biomarkers may offer a non-invasive strategy for detecting diabetic patients with increased risk of developing diabetic retinopathy (DR) or increased disease progression, thus helping both improving diagnostic accuracy and understanding the pathophysiology of the disease. Here, we assessed the tear fluid of nondiabetic individuals, diabetic patients with no DR, and diabetic patients with nonproliferative DR (NPDR) or with proliferative DR (PDR) to find putative biomarkers for the diagnosis and staging of DR.

Methods

Tear fluid samples were collected using Schirmer test strips from a cohort with 12 controls and 54 Type 2 Diabetes (T2D) patients, and then analyzed using mass spectrometry (MS)-based shotgun proteomics and bead-based multiplex assay. Tear fluid-derived small extracellular vesicles (EVs) were analyzed by transmission electron microscopy, Western Blotting, and nano tracking.

Results

Proteomics analysis revealed that among the 682 reliably quantified proteins in tear fluid, 42 and 26 were differentially expressed in NPDR and PDR, respectively, comparing to the control group. Data are available via ProteomeXchange with identifier PXD033101. By multicomparison analyses, we also found significant changes in 32 proteins. Gene ontology (GO) annotations showed that most of these proteins are associated with oxidative stress and small EVs. Indeed, we also found that tear fluid is particularly enriched in small EVs. T2D patients with NPDR have higher IL-2/-5/-18, TNF, MMP-2/-3/-9 concentrations than the controls. In the PDR group, IL-5/-18 and MMP-3/-9 concentrations were significantly higher, whereas IL-13 was lower, compared to the controls.

Conclusions

Overall, the results show alterations in tear fluid proteins profile in diabetic patients with retinopathy. Promising candidate biomarkers identified need to be validated in a large sample cohort.

Lab-on-a-chip technologies for minimally invasive molecular sensing of diabetic retinopathy

Diabetic retinopathy (DR) is the most common diabetic eye disease and the worldwide leading cause of vision loss in working-age adults. It progresses from mild to severe non-proliferative or proliferative DR based on several pathological features including the magnitude of blood-retinal barrier breakdown and neovascularization. Available pharmacological and retinal laser photocoagulation interventions are mostly applied in the advanced stages of DR and are inefficient in halting disease progression in a significantly high percentage of patients. Yet, recent evidence has shown that some therapies could potentially limit DR progression if applied at early stages, highlighting the importance of early disease diagnostics. In the past few decades, different imaging modalities have proved their utility for examining retinal and optic nerve changes in patients with retinal diseases. However, imaging based-methodologies solely rely on morphological examination of the retinal vascularization and are not suitable for recurrent and personalized patient evaluation. This raises the need for new technologies to enable accurate and early diagnosis of DR. In this review, we critically discuss the potential clinical benefit of minimally-invasive molecular biomarker identification and profiling of diabetic patients who are at risk of developing DR. We provide a comparative overview of conventional and recently developed lab-on-a-chip technologies for quantitative assessment of potential DR molecular biomarkers and discuss their advantages, current limitations and challenges for future practical implementation and continuous patient monitoring at the point-of-care.

LncRNA MCM3AP-AS1 is downregulated in diabetic retinopathy and promotes cell apoptosis by regulating miR-211/SIRT1

AIM

This study aimed to investigate the role of lncRNA MCM3AP-AS1 in diabetic retinopathy (DR).

METHODS

Plasma MCM3AP-AS1 levels in DR patients (n = 80), T2DM patients (n = 80), and Controls (n = 80) were measured by qPCR and compared using ANOVA (one-way) and Tukey test. The expressions of lncRNA MCM3AP-AS1 and miR-211 in Human retinal pigment epithelial cells (hRPE) line ARPE-19 were detected by RT-qPCR. Western blot and annexin V-FITC staining were performed to investigate the role of MCM3AP-AS1/SIRT1 in ARPE-19 cell proliferation and apoptosis in vitro.

RESULTS

We observed that MCM3AP-AS1 was downregulated in DR patients 25 comparing to T2D patients without significantly complications. Bioinformatics analysis showed that MCM3AP-AS1 might bind miR-211. However, no significant correlation between these two factors was observed in DR patients. Consistently, overexpression of MCM3AP-AS1 and miR-211 failed to affect the expression of each other in hRPE. Interestingly, MCM3AP-AS1 overexpression upregulated SIRT1, a target of miR-211. Moreover, MCM3AP-AS1 was downregulated in DR patients compared to type 2 diabetic mellitus patients without significant complications. In RPEs, high glucose treatment downregulated MCM3AP-AS1. Cell apoptosis analysis showed that MCM3AP-AS1 and SIRT1 overexpression decreased the apoptotic rate of RPEs, and miR-211 overexpression reduced the effect of MCM3AP-AS1 and SIRT1 overexpression.

CONCLUSION

MCM3AP-AS1 is downregulated in DR and promotes cell apoptosis by regulating miR-211/SIRT1.

Potential value of lncRNAs as a biomarker for proliferative diabetic retinopathy

OBJECTIVES

To investigate the differences in lncRNAs expression in whole blood between diabetic retinopathy (DR) patients and healthy subjects, and to evaluate the potential value of lncRNAs as a diagnostic biomarker for proliferative diabetic retinopathy (PDR).

METHODS

A series of 34 PDR patients, 34 patients with non-proliferative DR (NPDR) and 34 healthy participants were enroled. Differentially expressed lncRNAs were demonstrated using high-throughput sequencing and validated using qRT-PCR. Gene Ontology (GO) was performed to explore the possible biological function of the differentially expressed lncRNAs. lncRNA/mRNA coexpression network was built to determine the targets of differentially expressed lncRNAs. Receiver operating characteristic (ROC) analysis was utilized to evaluate the diagnostic value of lncRNAs for PDR.

RESULTS

We identified 175 and 179 differentially expressed lncRNAs in PDR patients compared with control samples and NPDR patients, respectively. GO analysis showed that the various metabolic processes were possibly influenced by these dysregulated lncRNAs. Using the differently expressed lncRNAs data, we further identified 82 overlapping lncRNAs in PDR patients with NPDR and control subjects. Part of these overlapping lncRNAs was significantly correlated with nuclear factor kappa B (NF-κB) and Wnt signal pathways. ROC curves were constructed for two upregulated lncRNAs and the ROC analysis indicated that both of them had potential diagnostic value and could distinguish PDR from control subjects and NPDR patients.

CONCLUSIONS

LncRNAs expression was altered in PDR patients compared with NPDR and control subjects. Moreover, it provides a resource that lncRNAs might be novel diagnostic and prognostic biomarker for PDR.

LncRNA THRIL promotes high glucose-induced proliferation and migration of human retina microvascular endothelial cells through enhancing autophagy

AIMS

Diabetes retinopathy (DR) is associated with retinal microvascular system injury induced by high glucose (HG). This study aims to explore the role and mechanism of long non-coding RNA THRIL in regulating cell proliferation and migration of human retina microvascular endothelial cells (hRMECs) under HG condition.

METHOD

The gene and protein expression were detetced by RT-PCR and western blot, respectively. Cell proliferation and migration of hRMECs were examined using MTT assay and Transwell assay, respectively. The interaction between miR-125b-5p and THRIL or autophagy-related gene 4D (ATG4D) was analyzed using luciferase activity assay.

RESULTS

THRIL expression was induced by HG in hRMECs. THRIL overexpression enhanced the proliferation and migration of hRMECs induced by HG, whereas THRIL silencing yielded the opposite results. Furthermore, THRIL overexpression induced autophagy activation, and inhibition of autophagy by 3-methyladenine abrogated the promotory effects of THRIL overexpression on cell proliferation and migration of hRMECs. Mechanismly, THRIL inhibited miR-125b-5p to upregulate the expression of ATG4D (an important autophagy-related gene), thereby promoting autophagy. Moreover, miR-125b-5p overexpression or ATG4D silencing alone abolished the promoting effects of THRIL overexpression on HG-induced autophagy, proliferation and migration of hRMECs.

CONCLUSIONS

THRIL promotes HG-induced cell proliferation and migration of hRMECs through activation of autophagy via the miR-125b-5p/ATG4D axis. THRIL may serve as a potential therapeutic target for DR.

Long non-coding ribonucleic acid ATP2B1-AS1 modulates endothelial permeability through regulating the miR-4729-IQGAP2 axis in diabetic retinopathy

AIMS/INTRODUCTION

Mounting evidence shows that long non-coding RNAs (lncRNAs) are important to modulate the biological process of diabetic retinopathy (DR). We aimed to investigate the role of lncRNAs in DR and elucidate the exact mechanism.

MATERIALS AND METHODS

Real-time quantitative polymerase chain reaction was carried out to distinguish the lncRNA ATPase plasma membrane Ca2+ transporting 1 antisense RNA 1 (ATP2B1-AS1) expression in DR patients and HG-treated human retinal endothelial cells (HRECs). Dual-luciferase reporter system was used to verify that ATP2B1-AS1 could act as a microRNA (miR)-4729 sponge, and miR-4729 could bind to 3'UTR of IQ motif-containing GTPase-activating protein 2 (IQGAP2). Cell proliferation assay, wound healing migration assay, transwell assay, tube formation assay and immunofluorescence were used to investigate cell proliferation, migration and angiogenesis in HRECs.

RESULTS

The present results showed that ATP2B1-AS1 was downregulated in DR patients and high-glucose-induced HRECs. In gain- and loss-of-function assays, ATP2B1-AS1 overexpression could significantly reduce cell proliferation, migration, angiogenesis and permeability induced by high glucose in vitro. Additionally, we carried out dual-luciferase reporter experiments to determine that ATP2B1-AS1 could act as a miR-4729 sponge. ATP2B1-AS1 overexpression could rescue miR-4729 mimics and short hairpin RNA-IQGAP2 induced cell proliferation, migration and angiogenesis in HRECs.

CONCLUSIONS

The present study showed that ATP2B1-AS1 acted as a miR-4729 sponge to regulate IQGAP2 reducing high-glucose-induced endothelial dysfunction in DR.

Long Noncoding RNAs and Mitochondrial Homeostasis in the Development of Diabetic Retinopathy

Retinopathy is one of the most devastating complications of diabetes, which a patient fears the most. Hyperglycemic environment results in many structural, functional, molecular and biochemical abnormalities in the retina, and overproduction of mitochondrial superoxide, induced by hyperglycemic milieu, is considered to play a central role in the development of diabetic retinopathy. Expression of many genes associated with maintaining mitochondrial homeostasis is also altered. Recent research has shown that several long noncoding RNAs, RNAs with more than 200 nucleotides but without any reading frames, are aberrantly expressed in diabetes, and altered expression of these long noncoding RNAs is now being implicated in the development of diabetes and its complications including retinopathy. This review focuses the role of long noncoding RNAs in the development of diabetic retinopathy, with a special emphasis on the maintenance of mitochondrial homeostasis.

Epigenetic modifications in diabetes

Diabetes is now considered as a 'silent epidemic' that claims over four million lives every year, and the disease knows no socioeconomic boundaries. Despite extensive efforts by the National and International organizations, and cutting-edge research, about 11% world's population is expected to suffer from diabetes (and its complications) by year 2045. This life-long disease damages both the microvasculature and the macrovasculature of the body, and affects many metabolic and molecular pathways, altering the expression of many genes. Recent research has shown that external factors, such as environmental factors, lifestyle and pollutants can also regulate gene expression, and contribute in the disease development and progression. Many epigenetic modifications are implicated in the development of micro- and macro- vascular complications including DNA methylation and histone modifications of several genes implicated in their development. Furthermore, several noncoding RNAs, such as micro RNAs and long noncoding RNAs, are also altered, affecting many biochemical pathways. Epigenetic modifications, however, have the advantage that they could be passed to the next generation, or can be erased. They are now being explored as therapeutical target(s) in the cancer field, which opens up the possibility to use them for treating diabetes and preventing/slowing down its complications.

Research Progress of circRNAs in Inflammatory Mechanisms of Diabetic Retinopathy: An Emerging Star with Potential Therapeutic Targets

PURPOSE

 We summarized the existing studies to elaborate the biogenesis and function of circRNAs, the effect of aberrant circRNAs expression in the mechanism of inflammation and diabetic retinopathy (DR) respectively and further explored the vital roles of circRNAs in inflammation involved in DR. Methods: We conducted a systematical literature search of abundant electronic databases (PubMed, GeneMedical and MEDLINE) up to August 2021. Results: In this review, we exhibited the biogenesis and function of circRNAs and highlighted the components of inflammatory mediators implicated in DR. Numerous circRNAs, such as circHIPK3, circZNF609, circRNA_0084043, circ_0002570, circ_0041795, circEhmt1 and circ-ITCH were discovered to play vital roles in inflammation involved in DR, which provided new ideas for diagnosis and treatment of DR. Moreover, we proposed not only the epigenetic functions of circRNAs but also novel forms of the inflammatory response, including pyroptosis, to inspire further exploration and creative research in this field. Conclusion: CircRNAs were implicated in the progression and development of inflammation in DR via aberrant expression and modulation of gene expression, serving as an emerging star with potential therapeutic targets.

Gliquidone improves retinal injury to relieve diabetic retinopathy via regulation of SIRT1/Notch1 pathway

Background

Diabetic retinopathy (DR) is a common and potentially devastating microvascular complication of diabetes mellitus (DM). The main features of DR are inflammation and oxidative damage. Gliquidone (GLI) is confirmed to be a hypoglycemic drug by oral administration. The current study is aimed to investigate the role and mechanism of GLI on the pathogenesis of DR.

Methods

High glucose (HG)-induced human retinal endothelial cells (HRECs) were used to explore the anti-inflammatory and anti-oxidant effects of GLI on DR in vitro. Streptozotocin (STZ)-induced DM rats were used to investigate the effects of GLI on retinal structures, inflammation, and oxidative stress. The levels of SIRT1/Notch1 pathway-related proteins were determined by western blotting.

Results

GLI treatment promoted the viability and inhibited the apoptosis of HG-induced HRECs. Meanwhile, the levels of interleukin (IL)-6, IL-1β, tumour necrosis factor alpha and reactive oxygen species were suppressed, while both catalase and superoxide dismutase were elevated after GLI treatment in HG-induced HRECs. Furthermore, we found that Silencing information regulator 2 related enzyme 1 (SIRT1) silencing reversed the inhibiting effects of GLI on the levels of protein Notch1 and effector genes Hes1 and Hey2. Similar anti-inflammatory and anti-oxidant effects of GLI in STZ-induced DM rats were observed. Additionally, GLI administration also repressed vascular hyperpermeability in vivo.

Conclusion

GLI may be an effective agent to improve DR through repression of inflammation and oxidative stress via SIRT1/Notch1 pathway.

Long non-coding RNA MEG3 inhibits neovascularization in diabetic retinopathy by regulating microRNA miR-6720-5p and cytochrome B5 reductase 2

Diabetic retinopathy (DR) is a major cause of vision loss in working and elderly populations. long non-coding RNA (LncRNA) MEG3 is thought to have some effect on DR, but the exact mechanism remains to be clarified. The expression levels of lncRNA MEG3, miR-6720-5p, and cytochrome B5 reductase 2 (CYB5R2) in human retinal microvascular endothelial cells (hRMECs) were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), transwell migration, and tube formation assays were used to determine the cell viability, migration, and tube formation ability of hRMECs, respectively. The interaction of MEG3, miR-6720-5p, and CYB5R2 was detected and explored by a luciferase assay. The expression of MEG3 and CYB5R2 was upregulated and that of miR-6720-5p was downregulated in patients with DR and hRMECs treated with high glucose. Knocking down MEG3 or CYB5R2 promoted proliferation, migration, and neovascularization in hRMECs. The intervention of miR-6720-5p reversed the effect of MEG3 knockdown on hRMEC function, and this effect was eliminated by silencing CYB5R2. Therefore, MEG3 acted as a sponge to suppress miR-6720-5p and regulate the expression of CYB5R2, thereby inhibiting DR neovascularization.

Nuclear Genome-Encoded Long Noncoding RNAs and Mitochondrial Damage in Diabetic Retinopathy

Retinal mitochondria are damaged in diabetes-accelerating apoptosis of capillary cells, and ultimately, leading to degenerative capillaries. Diabetes also upregulates many long noncoding RNAs (LncRNAs), including LncMALAT1 and LncNEAT1. These RNAs have more than 200 nucleotides and no open reading frame for translation. LncMALAT1 and LncNEAT1 are encoded by nuclear genome, but nuclear-encoded LncRNAs can also translocate in the mitochondria. Our aim was to investigate the role of LncMALAT1 and LncNEAT1 in mitochondrial homeostasis. Using human retinal endothelial cells, the effect of high glucose on LncMALAT1 and LncNEAT1 mitochondrial localization was examined by RNA fluorescence in situ hybridization. The role of these LncRNAs in mitochondrial membrane potential (by JC-I staining), mtDNA integrity (by extended length PCR) and in protective mtDNA nucleoids (by SYBR green staining) was examined in MALAT1- or NEAT1-siRNA transfected cells. High glucose increased LncMALAT1 and LncNEAT1 mitochondrial expression, and MALAT1-siRNA or NEAT1-siRNA ameliorated glucose-induced damage to mitochondrial membrane potential and mtDNA, and prevented decrease in mtDNA nucleoids. Thus, increased mitochondrial translocation of LncMALAT1 or LncNEAT1 in a hyperglycemic milieu plays a major role in damaging the mitochondrial structural and genomic integrity. Regulation of these LncRNAs can protect mitochondrial homeostasis, and ameliorate formation of degenerative capillaries in diabetic retinopathy.

LncRNA XIST restrains the activation of Müller cells and inflammation in diabetic retinopathy via stabilizing SIRT1

BACKGROUND

Recent studies have provided strong evidence that lncRNAs play a functional regulatory role in diabetic retinopathy (DR). The purpose of this study was to investigate the effect of long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) in DR.

METHODS

A DR mouse model was established by intraperitoneal injection of streptozotocin (STZ), and then the mouse retinal Müller cells (mMCs) were isolated from retina tissues of mice. Human retinal Müller cell line (HMCs) and mMCs and were treated with high glucose (HG) to simulate an in vitro DR model. XIST expression was detected by qRT-PCR. Next, XIST overexpression was performed in mMCs and HMCs to examine its effect on the activation of Müller cells and production of pro-inflammatory cytokines. Subsequently, the interaction between XIST and SIRT1 was verified, and the ubiquitination level of SIRT1 as well as the stability of SIRT1 protein were assessed.

RESULTS

XIST was down-regulated in retinal tissues of DR mice and HG-induced HMCs. Overexpression of XIST inhibited HG-induced activation of mMCs and HMCs, and reduced the production of pro-inflammatory cytokines. XIST promoted SIRT1 expression via interacting with SIRT1 and inhibiting the ubiquitination of SIRT1. Furthermore, SIRT1 silencing partly abrogated the effect of XIST overexpression on the activation of mMCs and HMCs as well as the production of pro-inflammatory cytokines induced by HG.

CONCLUSION

We concluded that XIST restrained the activation of Müller cells and the production of pro-inflammatory cytokines via stabilizing SIRT1.

Protective Role of microRNA-200a in Diabetic Retinopathy Through Downregulation of PDLIM1

Background

Diabetic retinopathy (DR) is a most common microvascular complication and regarded as the leading cause of blindness in the working age population. The involvement of miR-200a in various disorders has become recognized, and the objective of this study was to identify the protective effect of miR-200a in the development of DR.

Methods

The contents of miR-200a and its potential target gene, PDZ and LIM domain protein 1 (PDLIM1), were detected in both in-vivo and in-vitro DR models. Retinal leakage and inflammatory factor concentrations were detected after vitreous injections of miR-200a/PDLIM1 vectors in mice. The cellular viability, apoptosis and cellular migration were investigated using trypan blue staining, flow cytometry and transwell assay with human retinal microvascular endothelial cells (HRMECs). Besides, the prediction and confirmation of miR-200a targeting PDLIM1 were conducted with bioinformation analyses and dual-luciferase reporter assay.

Results

Lower miR-200a and higher PDLIM1 levels were detected in both in-vivo and in-vitro DR models. Besides, it was found that miR-200a treatment would significantly inhibit retinal permeability and inflammatory factors. Through targeting PDLIM1, it was found that miR-200a could improve cellular viability, remit apoptotic status and reduce cellular migration significantly in high glucose-treated HRMECs.

Conclusion

Our results demonstrated that miR-200a could be used as a potential therapy target through down-regulating PDLIM1 in DR.

Suppressing long noncoding RNA OGRU ameliorates diabetic retinopathy by inhibition of oxidative stress and inflammation via miR-320/USP14 axis

Long noncoding RNAs (lncRNAs) are important regulators in various diseases including diabetic retinopathy (DR). In this study, DR patients exhibited significantly increased expression of serum LncRNA-OGRU compared with normal individuals. Streptozotocin (STZ)-challenged rats with DR also had higher OGRU expression in retinas than that of the control group, which was confirmed in Müller cells upon high glucose (HG) stimulation. OGRU knockdown remarkably decreased vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) expression in HG-incubated Müller cells. HG-induced inflammatory response and oxidative stress in vitro were markedly mitigated by OGRU knockdown through restraining IκBɑ/nuclear factor kappa beta (NF-κB) and improving nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways, respectively. Further studies indicated that OGRU suppression greatly restored miR-320 expression, and a negative correlation between them was detected in DR patients. We also found that miR-320 over-expression considerably restrained TGF-β1 signaling, and hindered inflammation and reactive oxygen species (ROS) production in HG-stimulated Müller cells. Additionally, OGRU knockdown or miR-320 over-expression could dramatically down-regulate ubiquitin-specific peptidase 14 (USP14) expression levels in HG-incubated Müller cells, and miR-320 could directly target USP14. Notably, OGRU/miR-320 axis-mediated TGF-β1 signaling, inflammation and ROS were largely dependent on USP14. Intriguingly, our results showed that USP14 directly interacted with transforming growth factor-beta type 1 receptor (TβR1), and impeded TβR1 ubiquitination and degradation. Furthermore, USP14 could also facilitate IκBɑ deubiquitination and degradation, exacerbating IκBɑ phosphorylation and NF-κB activation. Finally, our in vivo studies confirmed that OGRU knockdown considerably ameliorated DR progression in STZ-challenged rats through mediating the mechanisms observed in vitro. Collectively, these findings implicated that LncRNA-OGRU mediated DR progression through competing for miR-320 to regulate USP14 expression, and thus LncRNA-OGRU/miR-320/USP14 axis may be considered as a therapeutic target for DR treatment.

The potential role of m6A RNA methylation in diabetic retinopathy

Diabetic retinopathy (DR), a major microvascular complication of diabetes, affects most diabetic individuals and has become the leading cause of vision loss. Metabolic memory associated with diabetes retains the risk of disease occurrence even after the termination of glycemic insult. Further, various limitations associated with its current diagnostic and treatment strategies like unavailability of early diagnostic and treatment methods, variation in treatment response from patient to patient, and cost-effectiveness have driven the need to find alternative solutions. Post-transcriptional epigenetic modification of RNA mainly, N6-methyladenosine (m6A), is an emerging concept in the scientific community. It has an indispensable effect in various physiological and pathological conditions. m6A mediates its effect through the various reader, writer, and eraser proteins. Recent studies have shown the impact of m6A RNA modification on various disease conditions, including diabetes, but its role in diabetic retinopathy is still unclear. However, change in m6A levels has been observed in various prime aggravators of DR pathogenesis, such as inflammation, oxidative stress, and angiogenesis. Further, various non-coding RNAs like microRNA, lncRNA, and circRNA are also associated with DR, and m6A has been shown to affect all these non-coding RNAs. This review is concerned with the possible mechanisms through which alteration in m6A modification of RNA can participate in the DR progression and pathogenesis and its expected role in metabolic memory phenomena.

Burden of vision loss due to diabetic retinopathy in China from 1990 to 2017: findings from the global burden of disease study

PURPOSE

To conduct a detailed analysis on the burden of vision loss due to diabetic retinopathy (DR) by year, age and gender in China from 1990 to 2017.

METHODS

This is a between-country, retrospective, comparative burden-of-disease study. Prevalence and Years Lived with Disability (YLDs) data caused by DR in China and relative territories were extracted from the Global Burden of Disease (GBD) study 2017 to observe the changing trends of vision loss.

RESULTS

Prevalence and YLDs of DR in China increased significantly from 1990 to 2017. The age-standardized prevalence and YLDs rate witnessed a slowly declining trend recently. Higher prevalence and YLDs were observed in female subjects in the past three decades. Middle-aged and elderly people suffered from a higher burden of DR-induced vision loss. The total age-standardized prevalence rate of China in 1990 (17.68) and 2017 (21.88) was lower than that of other seven neighbouring countries. In 2017, moderate vision loss (MVL) (17.19) accounted for the largest proportion in China. The all-age YLDs of DR showed the second-highest increase (150.26%) while the age-standardized YLDs rate showed the third-highest increase (14.91%) among fifteen common causes of vision impairment (VI) from 1990 to 2017. China ranked 3rd among G20 countries in terms of all-age YLDs while ranked 18th in age-standardized YLDs rate in 2017.

CONCLUSIONS

In the past three decades, the prevalence and YLDs due to DR in China have improved in both genders. This study highlights the importance of prevention for DR, especially for women and the elderly.

Emerging Roles of Long Non-Coding RNAs in Diabetic Foot Ulcers

Diabetes mellitus is one of the most widespread metabolic diseases in the world, and diabetic foot ulcer (DFU), as one of its chronic complications, not only causes a large amount of physiological and psychological pain to patients but also places a tremendous burden on the entire economy and society. Despite significant advances in knowledge on the mechanism and in the treatment of DFU, clinical practice is still not satisfactory, and our understanding of its cellular and molecular pathogenesis is far from complete. Fortunately, progress in studying the roles of long non-coding RNAs (lncRNAs), which play important regulatory roles in the expression of genes at multiple levels, suggests that we can apply them in the early diagnosis and potential targeted intervention of DFU. In this review, we briefly summarize the current knowledge regarding the functional roles and potential mechanisms of reported lncRNAs in regulating DFU.

The Importance of Non-Coding RNAs in Neurodegenerative Processes of Diabetes-Related Molecular Pathways

Diabetes mellitus (DM) is a complex condition and serious health problem, with growing occurrence of DM-associated complications occurring globally. Persistent hyperglycemia is confirmed as promoting neurovascular dysfunction leading to irreversible endothelial cell dysfunction, increased neuronal cell apoptosis, oxidative stress and inflammation. These collaboratively and individually result in micro- and macroangiopathy as well as neuropathy demonstrated by progressive neuronal loss. Recently, major efforts have been pursued to select not only useful diagnostic and prognostic biomarkers, but also novel therapeutic approaches. Both microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) belong to a class of non-coding RNAs identified in most of the body fluids i.e., peripheral blood, cerebrospinal fluid, brain tissue and neurons. Numerous miRNAs, lncRNAs and their target genes are able to modulate signaling pathways known to play a role in the pathophysiology of progressive neuronal dysfunction. Therefore, they pose as promising biomarkers and treatment for the vast majority of neurodegenerative disorders. This review provides an overall assessment of both miRNAs' and lncRNAs' utility in decelerating progressive nervous system impairment, including neurodegeneration in diabetic pathways.

Extracellular Vesicles and MicroRNA: Putative Role in Diagnosis and Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR) is a complex, progressive, and heterogenous retinal degenerative disease associated with diabetes duration. It is characterized by glial, neural, and microvascular dysfunction, being the blood-retinal barrier (BRB) breakdown a hallmark of the early stages. In advanced stages, there is formation of new blood vessels, which are fragile and prone to leaking. This disease, if left untreated, may result in severe vision loss and eventually legal blindness. Although there are some available treatment options for DR, most of them are targeted to the advanced stages of the disease, have some adverse effects, and many patients do not adequately respond to the treatment, which demands further research. Oxidative stress and low-grade inflammation are closely associated processes that play a critical role in the development of DR. Retinal cells communicate with each other or with another one, using cell junctions, adhesion contacts, and secreted soluble factors that can act in neighboring or long-distance cells. Another mechanism of cell communication is via secreted extracellular vesicles (EVs), through exchange of material. Here, we review the current knowledge on deregulation of cell-to-cell communication through EVs, discussing the changes in miRNA expression profiling in body fluids and their role in the development of DR. Thereafter, current and promising therapeutic agents for preventing the progression of DR will be discussed.

Circulating long noncoding RNAs H19 and GAS5 are associated with type 2 diabetes but not with diabetic retinopathy: A preliminary study

Recently, a wide range of biological and pathological roles of long noncoding RNAs (lncRNAs) have been discovered. However, the potential role of circulating lncRNAs H19 and GAS5 in type 2 diabetes mellitus (T2DM) and diabetic retinopathy (DR) is not clear. Here, we assessed the plasma levels of H19 and GAS5 lncRNAs in T2DM patients with/without DR and evaluated if H19 and GAS5 pre-treatment plasma levels are a predictor of early response to a single aflibercept dose in DR subgroup. Plasma lncRNA expression profiles of 119 T2DM patients (66 with DR and 53 without DR) and 110 healthy controls were determined by quantitative reverse transcription PCR. The association of lncRNA expression profiles with clinical features and aflibercept early response in DR patients was investigated. Relative H19 expression levels were significantly increased in T2DM group (including DR and non-DR subgroups) vs. controls, while GAS5 levels were decreased in T2DM group (p < 0.001). There was no significant difference in H19 and GAS5 expression levels between DR and non-DR subgroups. H19 and GAS5 expression profiles were not significantly correlated with clinical parameters or response to aflibercept therapy in DR subgroup. Our findings indicate that the circulating lncRNAs H19 and GAS5 may be associated with T2DM prevalence but may not have an important diagnostic/prognostic role in DR or early response to aflibercept intravitreal injection in DR patients. Large-scale transcriptomic studies are warranted to validate our results and investigate other lncRNA candidates in T2DM.

Resolvin D2 prevents inflammation and oxidative stress in the retina of streptozocin-induced diabetic mice

Diabetic retinopathy is the main ocular complication of diabetes mellitus. The aim of this study was to investigate the protective effect and mechanism of resolvin D2 (RvD2) on diabetic retinopathy. Streptozocin-induced C57/BJ diabetic mice were divided into three groups: normal control, diabetes mellitus, and diabetes plus RvD2 treatment. After three months of diabetic model induction, exogenous RvD2 was injected, monthly for three months, into the vitreous cavity of mice in the diabetic treatment group. Retinal vascular leakage, ganglion cell apoptosis, inflammatory factor expression, and oxidative stress factors were detected one month after the last injection. The levels of retinal vascular leakage and ganglion cell apoptosis in diabetic mice treated with RvD2 were significantly lower than those in untreated diabetic mice, as were the retinal levels of inflammatory factors and oxidative stress. In conclusion, RvD2 might be used as a retinal protective factor for diabetes mellitus by reducing inflammation and oxidative stress.

Integrative analysis of competitive endogenous RNA network reveals the regulatory role of non-coding RNAs in high-glucose-induced human retinal endothelial cells

Background

Increasing evidence has suggested that non-coding RNAs (ncRNAs) play critical roles in the pathogenesis of diabetic retinopathy (DR), but their underlying mechanisms remain unclear. The purpose of this study was to determine latent key genes and to structure a competing endogenous RNA (ceRNA) regulatory network to discover the potential molecular mechanisms governing the effects of high glucose on human retinal endothelial cells (HRECs).

Methods

We obtained microarray data for long non-coding RNA (lncRNA) and mRNA of high-glucose-induced HREC samples from NCBI GEO datasets. The ceRNA network was screened using intersecting prediction results from miRcode, TargetScan, miRTarBase and miRDB. The protein–protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes and hub genes were obtained using the cytoHubba app. The ClusterProfiler package was applied for performing Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The expression of key RNAs was verified using the qRT-PCR method. A key ceRNA subnetwork was constructed based on the criticality of the genes and its binding sites were verified by luciferase reporter assay. The viability and apoptosis of HRECs were tested using the transfection of the miR-449c inhibitor.

Results

A total of 3,328 lncRNAs and 2,017 mRNAs were screened for differentially expressed (DE) profiles. The newly constructed ceRNA network was composed of 410 lncRNAs, 35 miRNAs and 122 mRNAs. The 10 hub genes were identified through the PPI network. GO and KEGG analysis revealed that DE mRNAs were mainly related to the positive regulation of the mRNA catabolic process, cell polarity, and the G1/S transition of mitotic and cell cycle signaling pathways. QRT-PCR was used to verify RNAs and the most important genes were screened out. A key ceRNA subnetwork OIP5-AS1/miR-449c/MYC was established. The binding site was verified by luciferase reporter assay. The expression levels of OIP5-AS1 and MYC increased after miR-449c inhibitor transfection, miR-449c decreased, HRECs activity increased, and apoptosis decreased, compared with the control group.

Conclusion

We successfully built the key ceRNA subnetwork, OIP5-AS1/miR-449c/MYC, by applying the GEO database for data analysis and mining. The results from the ceRNA network allow us to better understand the effect of ncRNAs on HRECs under hyperglycemic conditions and the pathogenesis of DR.

Elevated vitreous Lipocalin-2 levels of patients with proliferative diabetic retinopathy

BACKGROUND

Lipocalin-2 (LCN2) is a novel adipokine with potential roles in obesity, insulin resistance, and inflammation. This study aims to assess the concentrations of LCN2 and vascular endothelial growth factor (VEGF) expressed in the vitreous humors of patients with proliferative diabetic retinopathy (PDR).

METHODS

The concentrations of LCN2 and VEGF were measured from the vitreous of 67 patients undergoing vitrectomy (20 controls and 47 PDR) via enzyme-linked immunosorbent assay (ELISA). Patients with non-ocular pathology that could elevate the LCN2 level in the vitreous were excluded. PDR activity and a history of panretinal photocoagulation were used for further grouping analysis.

RESULTS

The vitreous concentration of LCN2 was statistically significantly higher in the PDR group compared to the control group (63,522 (30,009) pg/ml versus 1663 (1191) pg/ml, respectively; P < 0.001). VEGF level was also significantly higher in the PDR group than in the control group (1038 (1326) pg/ml versus 9 pg/ml, respectively; P < 0.001). The mean vitreous LCN2 and VEGF levels in active PDR patients were significantly higher than that of the inactive PDR patients. The mean LCN2 concentration in vitreous humor was significantly lower in the 28 PDR patients with a history of complete PRP (37,304 (16,651) pg/mL) in comparison with 19 PDR patients without preperformed panretinal photocoagulation or with preperformed incomplete panretinal photocoagulation (79,796 (24,391) pg/mL). A significant correlation between the vitreous LCN2 level and VEGF level was found in patients with PDR (R = 0.34; P = 0.019).

CONCLUSIONS

This report shows a significant increase of LCN2 in the vitreous fluid of patients with PDR and present a significant correlation between LCN2 and VEGF, suggesting LCN2 might be involved in the pathogenesis of PDR.

Knockdown of MALAT1 attenuates high-glucose-induced angiogenesis and inflammation via endoplasmic reticulum stress in human retinal vascular endothelial cells

Diabetic retinopathy (DR) is one of the most severe complications of diabetes mellitus, and retinal endoplasmic reticulum stress (ERS) plays an important role in the pathogenesis of DR. However, the exact mechanisms by which ERS mediates DR remain unclear. In this study, human retinal vascular endothelial cells (RVECs) were cultured in high-glucose (HG) medium to mimic the environment of DR. The expression of long non-coding RNA (lncRNA)-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was determined by quantitative real time PCR. ERS markers (glucose-regulated protein 78 [GRP78] and C/EBP homologous protein [CHOP]) were measured by immunofluorescence and western blotting. Cell viability was analyzed by the CCK-8 assay. The angiogenesis of RVECs was evaluated by tube formation assays. The levels of pro-inflammation cytokines TNF-α and IL-6 in RVECs were determined by ELISA assays. We found that exposure to HG levels upregulated MALAT1 and GRP78 expression in RVECs. While, GRP78 overexpression strengthened CHOP expression, cell proliferation suppression, capillary morphogenesis and inflammation in HG-treated RVECs. Importantly, knockdown of MALAT1 reversed HG-induced cell proliferation suppression, inhibited capillary morphogenesis, and inflammation in RVECs, and those effects were reversed by GRP78 overexpression. These results suggest that MALAT1 promotes HG-induced angiogenesis and inflammation in RVECs by upregulating ER stress, and might be target for treating DR.