MicroRNA-15b Targets VEGF and Inhibits Angiogenesis in Proliferative Diabetic Retinopathy

Mechanical loading-induced alveolar bone remodeling is suppressed in the diabetic state via the impairment of the specificity protein 1/vascular endothelial growth factor (SP1/VEGF) axis

AIMS/INTRODUCTION

Orthodontic treatment involves alveolar bone remodeling in response to mechanical loading, resulting in tooth movement through traction-side bone formation and compression-side bone resorption. However, there are conflicting reports regarding alveolar bone resorption during the orthodontic treatment of patients with diabetes.

MATERIALS AND METHODS

Diabetes was induced in 8-week-old C56BL/6J mice using streptozotocin (STZ). Four weeks after the injection of STZ, a mechanical load was applied between the first and second molars on the right side of the upper jaw using the Waldo method with orthodontic elastics in diabetic (DM) and normal (N) mice tooth movement, gene expression, osteoclast counts, alveolar bone residual volume, and bone beam structure were evaluated.

RESULTS

The duration until spontaneous elastic loss was significantly longer in the DM group, suggesting that tooth movement may be inhibited in the diabetic state. The number of osteoclasts at 7 days after mechanical loading and the alveolar bone resorption were both significantly lower in the DM group. The gene expression levels of vascular endothelial growth factor (VEGF), a protein related to alveolar bone remodeling, and specificity protein 1 (SP1), a transcription factor of the VEGF gene, were significantly lower in the DM group than in the N group on the compression side of mechanical loading.

CONCLUSIONS

Mechanical loading-induced alveolar bone remodeling is suppressed in the diabetic state. Our results suggest that VEGF is a key molecule involved in impaired bone remodeling under mechanical loading in the diabetic state.

miRNA changes associated with differentiation of human embryonic stem cells into human retinal ganglion cells

miRNA, short non-coding RNA, are rapidly emerging as important regulators in cell homeostasis, as well as potential players in cellular degeneration. The latter has led to interest in them as both biomarkers and as potential therapeutics. Retinal ganglion cells (RGC), whose axons connect the eye to the brain, are central nervous system cells of great interest, yet their study is largely restricted to animals due to the difficulty in obtaining healthy human RGC. Using a CRISPR/Cas9-based reporter embryonic stem cell line, human RGC were generated and their miRNA profile characterized using NanoString miRNA assays. We identified a variety of retinal specific miRNA upregulated in ESC-derived RGC, with half of the most abundant miRNA also detectable in purified rat RGC. Several miRNA were however identified to be unique to RGC from human. The findings show which miRNA are abundant in RGC and the limited congruence with animal derived RGC. These data could be used to understand miRNA's role in RGC function, as well as potential biomarkers or therapies in retinal diseases involving RGC degeneration.

Ginsenoside Ro prevents endothelial injury via promoting Epac1/AMPK- mediated mitochondria protection in early diabetic retinopathy

Diabetic retinopathy (DR) is a blinding complication of microangiopathy. First-line therapeutic drugs are all focused on late-stage DR and have several side effects, which could not meet clinical needs. The plant-derived ginsenoside Ro (Ro) has a variety of effective anti-inflammatory, immune-regulating, and cardiovascular protective effects, but its microvascular protective effects are rarely studied. This study aimed to explore the protective effect and mechanism of Ro on retinal microvascular endothelial cells in early stage of DR. We demonstrated that Ro exerted endothelial cell protection by regulating mitochondrial oxidative stress and autophagy in AGEs-injured endothelial cells. Moreover, Ro alleviated DR progress through improving retinal thickness and pathological changes in STZ-induced diabetic mice. Mechanically, Ro promotes the activation of Epac1-mediated AMPK signaling. On the contrary, the protective effects of Ro were abolished by Epac1 inhibitor in vitro or Epac1 knock down in vivo. Our results revealed the important role of Ro on the treatment of DR and suggested that targeting Epac1 may be a promising approach to prevent and treat DR.

microRNAs: critical targets for treating rheumatoid arthritis angiogenesis

Vascular neogenesis, an early event in the development of rheumatoid arthritis (RA) inflammation, is critical for the formation of synovial vascular networks and plays a key role in the progression and persistence of chronic RA inflammation. microRNAs (miRNAs), a class of single-stranded, non-coding RNAs with approximately 21-23 nucleotides in length, regulate gene expression by binding to the 3' untranslated region (3'-UTR) of specific mRNAs. Increasing evidence suggests that miRNAs are differently expressed in diseases associated with vascular neogenesis and play a crucial role in disease-related vascular neogenesis. However, current studies are not sufficient and further experimental studies are needed to validate and establish the relationship between miRNAs and diseases associated with vascular neogenesis, and to determine the specific role of miRNAs in vascular development pathways. To better treat vascular neogenesis in diseases such as RA, we need additional studies on the role of miRNAs and their target genes in vascular development, and to provide more strategic references. In addition, future studies can use modern biotechnological methods such as proteomics and transcriptomics to investigate the expression and regulatory mechanisms of miRNAs, providing a more comprehensive and in-depth research basis for the treatment of related diseases such as RA.

Capsiate Improves Glucose Metabolism by Improving Insulin Sensitivity in Diabetic Retinopathy Mice

PURPOSE

Capsiate (cap) is a metabolite that affects a number of biological processes, and diabetic retinopathy (DR) is now known to be the primary cause of end-stage eye illness.

METHODS

In order to examine the effects of the cap intervention on body weight, nutritional intake, changes in body weight composition, glucose metabolism levels, retinopathy, and oxidative stress levels, we proposed using a mouse model of diabetic retinopathy caused by STZ.

RESULTS

Our findings demonstrated that, in addition to increasing lean body mass and lowering fat body mass content, cap intervention significantly improved body weight and dietary consumption in STZ mice. Additionally, our results on glucose metabolism revealed that cap had a significant impact on insulin resistance and the stabilization of OGTT levels. In conclusion, we examined the levels of oxidative stress and retinopathy. We discovered that the cap intervention greatly reduced the levels of MDA and significantly improved the levels of VEGF and retinopathy. In contrast, the STZ group's levels of SOD, CAT, and GSH were significantly higher.

CONCLUSIONS

According to our research, the Cap intervention improved the damage caused by diabetic retinopathy by reversing the levels of oxidative stress and the disrupted state of glucose metabolism, which in turn decreased the levels of VEGF.

Investigating the relationship between blood metabolites and diabetic retinopathy using two-sample mendelian randomization and in vivo validation

We addressed fundamental questions about the influence of metabolites on the development of Diabetic retinopathy (DR), and explored the related pathological mechanism. Genome-wide association study (GWAS) database data for metabolites and DR were used to perform Mendelian randomization (MR) studies. The inverse variance weighting (IVW) was chosen as the primary analysis method. Sensitivity analysis was conducted using MR-PRESSO, leave-one-out and Cochran's Q test. Confounding factors were eliminated to ensure robustness. We also conducted metabolic pathway analysis. In vivo experimental validation was conducted using Sprague Dawley rats. The serum metabolites of the DR group rats and normal group rats were examined to evaluate the MR results. The screen identified eighteen metabolites associated with DR risk, twelve of which were known components. Seven metabolites were positively correlated with DR risk, while five could reduce it. Eight metabolites associated with proliferative DR (PDR) risk were identified, four of which are known components. Three of these were positively associated with PDR risk and one metabolite reduced PDR risk. Additionally, two possible metabolic pathways involved in the biological mechanism of DR were identified. The ELISA results showed that the serum levels of isoleucine and 4-HPA were significantly increased in DR rats, while the level of inosine was decreased. This study offers novel insights into the biological mechanisms underlying DR. Metabolites that are causally linked to DR may serve as promising biomarkers and therapeutic targets.

MicroRNA-2861 regulates the proliferation and apoptosis of human retinal vascular endothelial cells treated with high glucose by targeting NDUFB7

Objectives

Although anti-VEGF and retinal laser photocoagulation are two therapeutic modalities that have been used in the clinical treatment of diabetic retinopathy (DR), it is unknown how these modalities target vascular endothelial function in DR.

Methods

We first downloaded and analyzed the differential genes in two DR-related datasets, GSE60436 and GSE53257. The differential gene expression was then verified using RT-qPCR, and the most upregulated gene, NDUFB7, was selected for subsequent experiments. Subsequently, the role of NDUFB7 silencing and enforced expression on the proliferation and apoptosis of HRVECs was explored using CCK-8 assay, EDU proliferation assay and apoptotic TUNEL staining. In addition, the upstream potential miRNAs of NDUFB7 were predicted online using the Targetscan website. RT-qPCR, Western blotting (WB), and dual luciferase gene reporter assay were used to confirm the targeting connection between miR-2861 and NDUFB7. Finally, miR-2861 expression after high glucose (HG) treatment and its effect on proliferation and apoptosis of HRVECs under HG were investigated.

Results

In this study, we first downloaded and analyzed the differential genes in two DR-related datasets, GSE60436 and GSE53257. We found that TUFM, PRELID1, MRPL32, NDUFB7, MRPL4, MRPL40, HSD17B10 and SLC25A13 were upregulated in DR, and RT-qPCR showed that NDUFB7 was most upregulated. Subsequent CCK-8 assay, EDU proliferation assay and TUNEL staining showed that up-picked NDUFB7 promotes proliferation and inhibits apoptosis of HRVECs. In addition, the upstream potential miRNAs of NDUFB7 were predicted online using the Targetscan website. RT-qPCR, Western blotting (WB), and dual luciferase gene reporter assay confirmed the targeting connection between miR-2861 and NDUFB7. Finally, it was observed that miR-2861 can inhibit the proliferation and promote the apoptosis of HRVECs by targeting NDUFB7.

Conclusions

Our findings showed that upregulated NDUFB7 in DR promotes proliferation and inhibits apoptosis of HRVECs, and miR-2861 can rescue the pathogenic effect of NDUFB7 upregulation by targeting NDUFB7.

Decrease of alpha-crystallin A by miR-325-3p in retinal cells under blue light exposure

Exposure to blue light can lead to retinal degeneration, causing adverse effects on eye health. Although the loss of retinal cells due to blue light exposure has been observed, the precise molecular mechanisms underlying this process remain poorly understood. In this study, we investigate the role of alpha-crystallin A (CRYAA) in neuro-retinal degeneration and their regulation by blue light. We observed significant apoptotic cell death in both the retina of rats and the cultured neuro-retinal cells. The expressions of Cryaa mRNA and protein were significantly downregulated in the retina exposed to blue light. We identified that miR-325-3p reduces Cryaa mRNA and protein by binding to its 3'-untranslated region. Upregulation of miR-325-3p destabilized Cryaa mRNA and suppresses CRYAA, whereas downregulation of miR-325-3p increased both expressions. Blue light-induced neuro-retinal cell death was alleviated by CRYAA overexpression. These results highlight the critical role of Cryaa mRNA and miR-325-3p molecular axis in blue light-induced retinal degeneration. Consequently, targeting CRYAA and miR-325-3p presents a potential strategy for protecting against blue light-induced retinal degeneration.

MicroRNA-15b promotes cardiac ischemia injury by the inhibition of Mitofusin 2/PERK pathway

MicroRNA and mitofusin-2 (Mfn2) play an important role in the myocardial apoptosis induced by acute myocardial infarction (AMI). However, the target relationship and underlying mechanism associated with interorganelle interaction between endoplasmic reticulum (ER) and mitochondria under ischemic condition is not completely clear. MI-induced injury, Mfn2 expression, Mfn2-mediated mitochondrial function and ER stress, and target regulation by miRNA-15b (miR-15b) were evaluated by animal MI and cellular hypoxic models with advanced molecular techniques. The results confirmed that Mfn2 was down-regulated and miR-15b was up-regulated upon the target binding profile under ischemic/hypoxic condition. Our data showed that miR-15b caused cardiac apoptotic injury that was reversed by rAAV9-anti-miR-15b or AMO-15b. The damage effect of miR-15b on Mfn2 expression and mitochondrial function was observed and rescued by rAAV9-anti-miR-15b or AMO-15b. The targeted regulation of miR-15b on Mfn2 was verified by luciferase reporter and microRNA-masking. Importantly, miR-15b-mediated Mfn2 suppression activated PERK/CHOP pathway, by which leads to ER stress and mitochondrial dysfunction, and cardiac apoptosis eventually. In conclusion, our research, for the first time, revealed the missing molecular link in Mfn2 and apoptosis and elucidated that pro-apoptotic miR-15b plays crucial roles during the pathogenesis of AMI through down-regulation of Mfn2 and activation of PERK-mediated ER stress. These findings may provide an opportunity to develop new therapies for prophylaxis and treatment of ischemic heart disease.

Study on the bioactive ingredients and mechanism of Huangqi against diabetic retinopathy based on network pharmacology and experimental verification

BACKGROUND

Diabetic retinopathy (DR) is one of the most well-known microvascular complications of diabetes mellitus. As a traditional Chinese medicine, Huangqi (HQ), has been used for treating DR for a long time. However, its anti-DR active ingredients and mechanism are still unknown. Therefore, we designed this study to explore the active components and mechanism of HQ against DR via network pharmacology analysis.

METHODS

The ingredients of HQ, and potential targets of HQ and DR were obtained from public databases. We used the protein-protein interaction (PPI) network, Kyoto Encyclopedia of Genes and Genomes (KEGGs) pathway enrichment, and Gene Ontology (GO) analysis to identify core targets and pathways of HQ against DR. Finally, molecular docking and vitro experiments were applied to validate our results.

RESULTS

A total of 34 potential targets of HQ against DR were obtained. Based on PPI network, VEGFA, PTGS2, Interleukin-6 (IL-6), and CCL2 were considered as core targets. GO analysis involved 692 biological processes, 21 cellular components, and 35 molecular functions. KEGG enrichment analysis manifested that the anti-DR effect of HQ was mainly mediated via the AGE-RAGE signaling pathway in diabetic complications. The molecular docking results indicated that kaempferol had higher affinity with CCL2, IL-6, VEGFA, and PTGS2. The vitro experiments showed that the mRNA expressions of CCL2, IL-6, VEGFA, and PTGS2 in ARPE-19 cells were differentially decreased after kaempferol treatment.

CONCLUSION

This study preliminarily unveiled that the therapeutic efficacy of HQ against DR might be attributed to the reduced expression of CCL2, IL-6, VEGFA, and PTGS2.

Rheumatoid arthritis and diabetic retinopathy: A two-sample Mendelian randomization study

Diabetic retinopathy (DR) is a common and highly blinding disease. Many clinical studies have shown a causal relationship between Rheumatoid arthritis (RA) and DR, but the results are contradictory. In addition, some clinical results and pathological inferences have certain paradoxes, and the influence of RA on the pathogenesis and development of DR Is unclear. Our research assessed the causal association between RA and the development of DR using a 2-sample Mendelian randomization method. Single nucleotide polymorphisms (SNPs) relevant to the study were extracted and filtered from genome-wide association study (GWAS) data. A DR GWAS with a sample size of 190,594 and an RA GWAS with a sample size of 58,284 were obtained. Inverse variance weighted (IVW) method was used to analyze the results, and Mendelian randomization (MR)-Egger regression method and weighted median method were used to evaluate the robustness. Sensitivity analysis was performed using pleiotropy test, heterogeneity test, leave-one-out test to ensure that the results were unbiased. Confounding factors were eliminated to ensure robustness. A total of 83 related SNPs were screened. IVW method showed a positive correlation between RA and the increased relative risk of diabetic retinopathy (OR = 1.06, 95%CI: 1.04-1.23). The same trend was shown by MR-Egger regression method and weighted median method. Sensitivity analysis showed that there was no heterogeneity in SNPs, and the results were less likely to be affected by potential bias. After removing SNPs linked to confounders, the MR results remained significant and stable in direction. There is a positive causal association between rheumatoid arthritis and diabetic retinopathy. It is important to strengthen retina-related screening and prevention in diabetic patients with RA to reduce the risk of DR In RA patients.

Treatment of diabetic retinopathy with herbs for tonifying kidney and activating blood circulation: A review of pharmacological studies

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic retinopathy (DR) is a prevalent microvascular complication of diabetes. Chinese medicine believes that kidney deficiency and blood stasis are significant pathogenesis of DR. A characteristic therapeutic approach for this pathogenesis is the kidney-tonifying and blood-activating method. By literature retrieval from several databases, we methodically summarized the commonly used kidney-tonifying and blood-activating herbs for treating DR, including Lycii Fructus, Rehmanniane Radix Praeparata, and Corni Fructus with the function of nourishing kidney; Salvia Miltiorrhizae Radix et Rhizoma with the function of enhancing blood circulation; Rehmanniae Radix with the function of nourishing kidney yin; and Astragali Radix with the function of tonifying qi. It has been demonstrated that these Chinese herbs described above, by tonifying the kidney and activating blood circulation, significantly improve the course of DR.

AIM OF THE STUDY

Through literature research, to gain a thorough comprehension of the pathogenesis of DR. Simultaneously, through the traditional application analysis, modern pharmacology research and network pharmacology analysis of kidney-tonifying and blood-activating herbs, to review the effectiveness and advantages of kidney-tonifying and blood-activating herbs in treating DR comprehensively.

MATERIALS AND METHODS

PubMed, the China National Knowledge Infrastructure (CNKI), and Wanfang Data were used to filter the most popular herbs for tonifying kidney and activating blood in the treatment of DR. The search terms were "diabetic retinopathy" and "tonifying kidney and activating blood". Mostly from 2000 to 2023. Network pharmacology was applied to examine the key active components and forecast the mechanisms of kidney-tonifying and blood-activating herbs in the treatment of DR.

RESULTS

Kidney deficiency and blood stasis are the pathogenesis of DR, and the pathogenesis is linked to oxidative stress, inflammation, hypoxia, and hyperglycemia. Scientific data and network pharmacology analysis have demonstrated the benefit of tonifying kidney and activating blood herbs in treating DR through several channels, multiple components, and multiple targets.

CONCLUSIONS

This review first presents useful information for subsequent research into the material foundation and pharmacodynamics of herbs for tonifying kidney and activating blood, and offers fresh insights into the treatment of DR.

MicroRNA-1225-5p Promotes the Development of Fibrotic Cataracts via Keap1/Nrf2 Signaling

PURPOSE

Fibrotic cataracts, including anterior subcapsular cataract (ASC) as well as posterior capsule opacification (PCO), are a common vision-threatening cause worldwide. Still, little is known about the underlying mechanisms. Here, we demonstrate a miRNA-based pathway regulating the pathological fibrosis process of lens epithelium.

METHODS

Gain- and loss-of-function approaches, as well as multiple fibrosis models of the lens, were applied to validate the crucial role of two miR-1225 family members in the TGF-β2 induced PCO model of human LECs and injury-induced ASC model in mice.

RESULTS

Both miR-1225-3p and miR-1225-5p prominently stimulate the migration and EMT process of lens epithelial cells (LECs) in vitro as well as lens fibrosis in vivo. Moreover, we demonstrated that the underlying mechanism for these effects of miR-1225-5p is via directly targeting Keap1 to regulate Keap1/Nrf2 signaling. In addition, evidence showed that Keap1/Nrf2 signaling is activated in the TGF-β2 induced PCO model of human LECs and injury-induced ASC model in mice, and inhibition of the Nrf2 pathway can significantly reverse the process of LECs EMT as well as lens fibrosis.

CONCLUSIONS

These results suggest that blockade of miR-1225-5p prevents lens fibrosis via targeting Keap1 thereby inhibiting Nrf2 activation. The 'miR-1225-Keap1-Nrf2' signaling axis presumably holds therapeutic promise in the treatment of fibrotic cataracts.

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.

The Role of Natural Products in Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the most severe complications of diabetes mellitus and potentially leads to significant visual impairment and blindness. The complex mechanisms involved in the pathological changes in DR make it challenging to achieve satisfactory outcomes with existing treatments. Diets conducive to glycemic control have been shown to improve outcomes in diabetic patients, thus positioning dietary interventions as promising avenues for DR treatment. Investigations have demonstrated that natural products (NPs) may effectively manage DR. Many types of natural compounds, including saponins, phenols, terpenoids, flavonoids, saccharides, alkaloids, and vitamins, have been shown to exert anti-inflammatory, antioxidant, anti-neovascular, and antiapoptotic effects in vivo and in vitro. Nevertheless, the clinical application of NPs still faces challenges, such as suboptimal specificity, poor bioavailability, and a risk of toxicity. Prospective clinical studies are imperative to validate the therapeutic potential of NPs in delaying or preventing DR.

LncRNA XIST promotes neovascularization in diabetic retinopathy by regulating miR-101-3p/VEGFA

Objective

This study sought to investigate the regulation of long noncoding RNA (lncRNA) XIST on the microRNA (miR)-101-3p/vascular endothelial growth factor A (VEGFA) axis in neovascularization in diabetic retinopathy (DR).

Materials and methods

Serum of patients with DR was extracted for the analysis of XIST, miR-101-3p, and VEGFA expression levels. High glucose (HG)-insulted HRMECs and DR model rats were treated with lentiviral vectors. MTT, transwell, and tube formation assays were performed to evaluate cell viability, migration, and angiogenesis, and ELISA was conducted to detect the levels of inflammatory cytokines. Dual-luciferase reporter, RIP, and RNA pull-down experiments were used to validate the relationships among XIST, miR-101-3p, and VEGFA.

Results

XIST and VEGFA were upregulated and miR-101-3p was downregulated in serum from patients with DR. XIST knockdown inhibited proliferation, migration, vessel tube formation, and inflammatory responsein HG-treated HRMECs, whereas the above effects were nullified by miR-101-3p inhibition or VEGFA overexpression. miR-101-3p could bind to XIST and VEGFA. XIST promoted DR development in rats by regulating the miR-101-3p/VEGFA axis.

Conclusion

LncRNA XIST promotes VEGFA expression by downregulating miR-101-3p, thereby stimulating angiogenesis and inflammatory response in DR.

Oxidative Stress Participates in Age-Related Cataract Formation by Disrupting Connection between Lens Epithelial Cells through c-Src/VEGF Pathway

PURPOSE

To observe the effects of oxidative stress on vascular endothelial growth factor (VEGF) and connections of lens epithelial cells.

METHODS

Human lens epithelium of patients with age-related cataract (ARC), both SRA01/04 cells and whole mice lens stimulated by H2O2 were employed. VEGF in human aqueous humor of ARC-patients and the supernatant of SRA01/04 cells was determined by ELISA. The expressions of VEFG in human lens epithelium were detected by immunofluorescence staining. Multiple linear regression analysis and spearman rank-order correlation were used to determine the associations between VEGF and parameters of ARC individuals. In H2O2-induced SRA01/04 cells, Catalase (CAT), PP1 (inhibitor of c-Src kinase) and Avastin (VEGF antibody) were used to inhibit the effects of H2O2, activation of c-Src kinase and VEGF, which were detected by Western blot. The alterations of ZO-1 and N-cadherin were tested by immunofluorescence staining and Western blot. In H2O2-induced whole lens, the changes of opacification area in different treatment of inhibitors were observed.

RESULTS

The secretion of VEGF in aqueous humor and expression of VEGF in the lens epithelium of ARC patients increased significantly with age. In H2O2-induced SRA01/04 cells, the VEGF in the supernatant was increased with the culture duration and the dose of H2O2. The expressions of p-Src418 and VEGF were also up-regulated, whereas the expressions of ZO-1 and N-cadherin were down-regulated. CAT effectively prevented these changes induced by H2O2, while PP1 inhibited not only p-Src418 but also up-regulation of VEGF, Avastin partially inhibited VEGF up-regulation. Both PP1 and Avastin prevented down-regulation of ZO-1 and N-cadherin, respectively, but Avastin combined with PP1 had no significant synergistic effects. In H2O2-induced cataract, CAT prevented development of opacification area effectively, and PP1 and Avastin did partially.

CONCLUSIONS

Oxidative stress disrupts connections of lens epithelial cells by activating c-Src/VEGF, inhibiting which may prevent cataract.

Inhibition of miR-29a-3p Alleviates Apoptosis of Lens Epithelial Cells via Upregulation of CAND1

PURPOSE

Accumulated evidence has shown that microRNAs (miRNAs) are closely related to the pathogenesis and progression of senile cataracts. Here we investigate the effect of miR-29a-3p in cataractogenesis and determined the potential molecular mechanism involved.

METHODS

In this study, we constructed a selenite cataract model in rats and obtained the miRNAs related to cataracts by whole transcriptome sequencing. To investigate the effect and mechanism of miR-29a-3p on cataracts, we performed several in vivo and in vitro experiments, including CCK8 assay, flow cytometry, luciferase reporter assay, Edu assay, and western blot analysis.

RESULT

Sequencing data showed downregulation of miR-29a-3p in rats with selenite cataracts. Down-regulation of miR-29a-3p could promote lens epithelial cells (SRA01/04) proliferation and inhibit cell apoptosis, and miR-29a-3p silence could inhibit the development of cataracts. Additionally, CAND1 was a direct target gene for miR-29a-3p.

CONCLUSION

These data demonstrate that miR-29a-3p inhibits apoptosis of lens epithelial cells by regulating CAND1, which may be a potential target for senile cataracts.

Roles of Sirt1 and its modulators in diabetic microangiopathy: A review

Diabetic vascular complications include diabetic macroangiopathy and diabetic microangiopathy. Diabetic microangiopathy is characterised by impaired microvascular endothelial function, basement membrane thickening, and microthrombosis, which may promote renal, ocular, cardiac, and peripheral system damage in diabetic patients. Therefore, new preventive and therapeutic strategies are urgently required. Sirt1, a member of the nicotinamide adenine dinucleotide-dependent histone deacetylase class III family, regulates different organ growth and development, oxidative stress, mitochondrial function, metabolism, inflammation, and aging. Sirt1 is downregulated in vascular injury and microangiopathy. Moreover, its expression and distribution in different organs correlate with age and play critical regulatory roles in oxidative stress and inflammation. This review introduces the background of diabetic microangiopathy and the main functions of Sirt1. Then, the relationship between Sirt1 and different diabetic microangiopathies and the regulatory roles mediated by different cells are described. Finally, we summarize the modulators that target Sirt1 to ameliorate diabetic microangiopathy as an essential preventive and therapeutic measure for diabetic microangiopathy. In conclusion, targeting Sirt1 may be a new therapeutic strategy for diabetic microangiopathy.

miR-196b-5p regulates inflammatory process and migration via targeting Nras in trabecular meshwork cells

Glaucoma, an insidious ophthalmic pathology, is typified by an aberrant surge in intraocular pressure (IOP) which culminates in the degeneration of retinal ganglion cells and optical neuropathy. The mitigation of IOP stands as the principal therapeutic strategy to forestall vision loss. The trabecular meshwork's (TM) integrity and functionality are pivotal in modulating aqueous humor egress. Despite their potential significance in glaucomatous pathophysiology, the implications of microRNAs (miRNAs) on TM functionality remain largely enigmatic. Transcriptomic sequencing was employed to delineate the miRNA expression paradigm within the limbal region of rodent glaucoma models, aiming to elucidate miRNA-mediated mechanisms within the glaucomatous milieu. Analytical scrutiny of the sequencing data disclosed 174 miRNAs with altered expression profiles, partitioned into 86 miRNAs with augmented expression and 88 with diminished expression. Notably, miRNAs such as hsa-miR-196b-5p were identified as having substantial expression discrepancies with concomitant statistical robustness, suggesting a potential contributory role in glaucomatous progression. Subsequent in vitro assays affirmed that miR-196b-5p augments the inflammatory cascade within immortalized human TM (iHTM) and glaucoma-induced human TM (GTM3) cells, concurrently attenuating cellular proliferation, motility, and cytoskeletal architecture. Additionally, miR-196b-5p implicates itself in the regulation of IOP and inflammatory processes in rodent models. At a mechanistic level, miR-196b-5p modulates its effects via the targeted repression of Nras (neuroblastoma RAS viral oncogene homolog). Collectively, these transcriptomic investigations furnish a comprehensive vista into the regulatory roles of miRNAs within the glaucomatous framework, and the identification of differentially expressed miRNAs alongside their targets could potentially illuminate novel molecular pathways implicated in glaucoma, thereby aiding in the development of innovative therapeutic avenues.

Advances in Research Related to MicroRNA for Diabetic Retinopathy

Diabetic retinopathy (DR) is a severe microvascular complication of diabetes and is one of the primary causes of blindness in the working-age population in Europe and the United States. At present, no cure is available for DR, but early detection and timely intervention can prevent the rapid progression of the disease. Several treatments for DR are known, primarily ophthalmic treatment based on glycemia, blood pressure, and lipid control, which includes laser photocoagulation, glucocorticoids, vitrectomy, and antivascular endothelial growth factor (anti-VEGF) medications. Despite the clinical efficacy of the aforementioned therapies, none of them can entirely shorten the clinical course of DR or reverse retinopathy. MicroRNAs (miRNAs) are vital regulators of gene expression and participate in cell growth, differentiation, development, and apoptosis. MicroRNAs have been shown to play a significant role in DR, particularly in the molecular mechanisms of inflammation, oxidative stress, and neurodegeneration. The aim of this review is to systematically summarize the signaling pathways and molecular mechanisms of miRNAs involved in the occurrence and development of DR, mainly from the pathogenesis of oxidative stress, inflammation, and neovascularization. Meanwhile, this article also discusses the research progress and application of miRNA-specific therapies for DR.

TNFα-Induced Altered miRNA Expression Links to NF-κB Signaling Pathway in Endometriosis

Endometriosis is a common gynecological inflammatory disorder characterized by immune system dysregulation, which is involved in lesion initiation and progression. Studies have demonstrated that several cytokines are associated with the evolution of endometriosis, including tumor necrosis factor-α (TNFα). TNFα is a non-glycosylated cytokine protein with potent inflammatory, cytotoxic, and angiogenic potential. In the current study, we examined the ability of TNFα to induce dysregulation of microRNAs (miRNAs) linked to NFkB signaling pathways, thus contributing to the pathogenesis of endometriosis. Using RT-qPCR, the expression of several miRNAs was quantified in primary cells derived from eutopic endometrium of endometriosis subjects (EESC) and normal endometrial stromal cells (NESC), and also TNFα-treated NESCs. The phosphorylation of the pro-inflammatory molecule NF-κB and the candidates of the survival pathways PI3K, AKT, and ERK was measured by western blot analysis. The elevated secretion of TNFα in EESCs downregulates the expression level of several miRNAs significantly in EESCs compared to NESCs. Also, treatment of NESCs with exogenous TNFα significantly reduced the expression of miRNAs in a dose-dependent manner to levels similar to EESCs. In addition, TNFα significantly increased the phosphorylation of the PI3K, AKT, ERK, and NF-κB signaling pathways. Notably, treatment with curcumin (CUR, diferuloylmethane), an anti-inflammatory polyphenol, significantly increased the expression of dysregulated miRNAs in EESC in a dose-dependent manner. Our findings demonstrate that TNFα is upregulated in EESCs, which subsequently dysregulates the expression of miRNAs, contributing to the pathophysiology of endometriotic cells. CUR effectively inhibits the expression of TNFα, subsequently altering miRNA levels and suppressing the phosphorylation of AKT, ERK, and NF-κB.

Bioinformatics and in vitro study reveal the roles of microRNA-346 in high glucose-induced human retinal pigment epithelial cell damage

AIM

To study microRNAs (miRNAs) and their potential effects in high glucose-induced human retinal pigment epithelial cell damage.

METHODS

We screened the GSE52233 miRNA expression dataset for differentially expressed miRNAs (DEMs). The target genes of the top 10 DEMs were predicted using miRWalk 2.0 database, followed by function enrichment and protein-protein interaction analysis. miRNA expression was determined in the human retinal pigment epithelial cell line ARPE-19 treated with high glucose (HG) by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell proliferation was determined using cell counting kit (CCK)-8 assay. Cell cycle, apoptosis, and reactive oxygen species (ROS) levels were determined by flow cytometry. The direct interaction between miRNA and targets was validated using dual-luciferase reporter assay.

RESULTS

Thirty-nine DEMs were screened, and we predicted 125 miRNA-mRNA pairs for the top 10 DEMs, including 119 target genes of seven DEMs such as miR-346, which was upregulated in diabetic retinopathy (DR). miR-346 target genes were substantially enriched in the regulation of intracellular transport and retinoic acid-inducible gene I (RIG-I)-like receptor signaling pathway. Expression of three upregulated and downregulated miRNAs were verified by qRT-PCR in HG-treated ARPE-19 cells. Expression of miR-346 was elevated in HG treated ARPE-19 cells in a dose-dependent manner. HG inhibited cell proliferation and induced apoptosis, which were partly reversed by transfecting an miR-346 inhibitor, which even decreased the ROS levels elevated due to HG. Argonaute 2 (AGO2) was a target of miR-346.

CONCLUSION

miR-346 is a key miRNA and plays an important role in HG-induced damage in human retinal pigment epithelial cells.

Potential Retinal Biomarkers in Alzheimer's Disease

Alzheimer's disease (AD) represents a major diagnostic challenge, as early detection is crucial for effective intervention. This review examines the diagnostic challenges facing current AD evaluations and explores the emerging field of retinal alterations as early indicators. Recognizing the potential of the retina as a noninvasive window to the brain, we emphasize the importance of identifying retinal biomarkers in the early stages of AD. However, the examination of AD is not without its challenges, as the similarities shared with other retinal diseases introduce complexity in the search for AD-specific markers. In this review, we address the relevance of using the retina for the early diagnosis of AD and the complex challenges associated with the search for AD-specific retinal biomarkers. We provide a comprehensive overview of the current landscape and highlight avenues for progress in AD diagnosis by retinal examination.

Roles of non-coding RNAs in eye development and diseases

The prevalence of ocular disorders is dramatically increasing worldwide, especially those that cause visual impairment and permanent loss of vision, including cataract, glaucoma, age-related macular degeneration, and diabetic retinopathy. Extensive evidence has shown that ncRNAs are key regulators in various biogenesis and biological functions, controlling gene expression related to histogenesis and cell differentiation in ocular tissues. Aberrant expression and function of ncRNA can lead to dysfunction of visual system and mediate progression of eye disorders. Here, we mainly offer an overview of the role of precise modulation of ncRNAs in eye development and function in patients with eye diseases. We also highlight the challenges and future perspectives in conducting ncRNA studies, focusing specifically on the role of ncRNAs that may hold expanded promise for their diagnostic and therapeutic applications in various eye diseases. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Efficacy of ranibizumab combined with photocoagulation for diabetic retinopathy: A meta-analysis study

BACKGROUND

Ranibizumab addition may benefit to improve the efficacy in patients with diabetic retinopathy than only photocoagulation, and this meta-analysis aims to explore the impact of ranibizumab addition on efficacy for diabetic retinopathy.

METHODS

PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases were systematically searched, and we included randomized controlled trials assessing the effect of ranibizumab addition on patients with diabetic retinopathy for this meta-analysis.

RESULTS

Six randomized controlled trials were finally included in the meta-analysis. Overall, compared with control intervention for diabetic retinopathy, ranibizumab addition showed significantly increased number of neovascularization area reduction (OR = 4.20; 95% CI = 1.47-12.02; P = .007) and reduced fluorescein leakage (MD = -2.53; 95% CI = -3.31 to -1.75; P < .00001), but showed no obvious impact on neovascularization area (MD = -1.80; 95% CI = -3.68 to 0.08; P = .06), photocoagulation retreatment (OR = 1.03; 95% CI = 0.47-2.27; P = .94) or adverse events (OR = 1.45; 95% CI = 0.49-4.29; P = .50).

CONCLUSIONS

Ranibizumab combined with photocoagulation is effective to improve efficacy for diabetic retinopathy.

Epigenetic modifications and metabolic memory in diabetic retinopathy: beyond the surface

Epigenetics focuses on DNA methylation, histone modification, chromatin remodeling, noncoding RNAs, and other gene regulation mechanisms beyond the DNA sequence. In the past decade, epigenetic modifications have drawn more attention as they participate in the development and progression of diabetic retinopathy despite tight control of glucose levels. The underlying mechanisms of epigenetic modifications in diabetic retinopathy still urgently need to be elucidated. The diabetic condition facilitates epigenetic changes and influences target gene expression. In this review, we summarize the involvement of epigenetic modifications and metabolic memory in the development and progression of diabetic retinopathy and propose novel insights into the treatment of diabetic retinopathy.

TNFα-induced altered miRNA expression links to NF-κB signaling pathway in endometriosis

Endometriosis is a common gynecological inflammatory disorder characterized by immune system dysregulation, which is involved in lesion initiation and progression. Studies have demonstrated that several cytokines are associated with the evolution of endometriosis, including tumor necrosis factor-α (TNFα). TNFα is a non-glycosylated cytokine protein with potent inflammatory, cytotoxic, and angiogenic potential. In the current study, we examined the ability of TNFα to induce dysregulation of microRNAs (miRNAs) linked to NFkB-signaling pathways, thus contributing to the pathogenesis of endometriosis. Using RT-QPCR, the expression of several miRNAs were quantified in primary cells derived from eutopic endometrium of endometriosis subjects (EESC) and normal endometrial stromal cells (NESC) and also TNFα treated NESCs. The phosphorylation of the pro-inflammatory molecule NF-κB and the candidates of the survival pathways PI3K, AKT and ERK was measured by westernblot analysis. The elevated secretion of TNFα in EESCs downregulates the expression level of several miRNAs significantly (p < 0.05) in EESCs compared to NESC. Also treatment of NESCs with exogenous TNFα significantly reduced the expression of miRNAs in a dose-dependent manner to levels similar to EESCs. In addition, TNFα significantly increased the phosphorylation of the PI3K, AKT, ERK, and NF-κB signaling pathways. Notably, treatment with curcumin (CUR, diferuloylmethane), an anti-inflammatory polyphenol, significantly increased the expression of dysregulated miRNAs in EESC in a dose-dependent manner. Our findings demonstrate that TNFα is upregulated in EESCs, which subsequently dysregulates the expression of miRNAs, contributing to the pathophysiology of endometriotic cells. CUR effectively inhibits the expression of TNFα, subsequently altering miRNA levels and suppresses the phosphorylation of AKT, ERK, and NF-κB.

The role of EZH2 in ocular diseases: a narrative review

EZH2, acting as a catalytic subunit of PRC2 to catalyze lysine 27 in histone H3, induces the suppression of gene expression. EZH2 can regulate cell proliferation and differentiation of retinal progenitors, which are required for physiological retinal development. Meanwhile, an abnormal level of EZH2 has been observed in ocular tumors and other pathological tissues. This review summarizes the current knowledge on EZH2 in retinal development and ocular diseases, including inherited retinal diseases, ocular tumors, corneal injury, cataract, glaucoma, diabetic retinopathy and age-related retinal degeneration. We highlight the potential of targeting EZH2 as a precision therapeutic target in ocular diseases.

Vaccinium as Potential Therapy for Diabetes and Microvascular Complications

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

Network meta-analysis of intravitreal conbercept as an adjuvant to vitrectomy for proliferative diabetic retinopathy

Purpose

Intravitreal Conbercept (IVC) has been shown to be effective in treating proliferative diabetic retinopathy (PDR) as an adjuvant in pars plana vitrectomy (PPV); however, the best timing of IVC injection remains unknown. This network meta-analysis (NMA) sought to ascertain the comparative efficacy of different timings of IVC injection as an adjuvant to PPV on PDR.

Methods

A comprehensive literature search was conducted in PubMed, EMBASE, and the Cochrane Library to identify relevant studies published before August 11, 2022. According to the mean time of IVC injection before PPV, the strategy was defined as very long interval if it was > 7 days but ≤ 9 days, long interval if it was > 5 days but ≤ 7 days, mid interval if it was > 3 days but ≤ 5 days, and short interval if it was ≤ 3 days, respectively. The strategy was defined as perioperative IVC if IVC was injected both before and at the end of PPV, and the strategy was intraoperative IVC if injected immediately at the end of PPV. The mean difference (MD) and odds ratio (OR) with corresponding 95% confidence interval (CI) for continuous and binary variables, respectively, were computed through network meta-analysis using Stata 14.0 MP.

Results

Eighteen studies involving 1149 patients were included. There was no statistical difference between intraoperative IVC and control in treating PDR. Except for a very long interval, preoperative IVC significantly shortened operation time, and reduced intraoperative bleeding and iatrogenic retinal breaks. Long and short intervals reduced endodiathermy application, and mid and short intervals reduced postoperative vitreous hemorrhage. Moreover, long and mid intervals improved BCVA and central macular thickness. However, very long interval was associated with an increased risk of postoperative vitreous hemorrhage (RR: 3.27, 95%CI: 1.84 to 5.83). Moreover, mid interval was better than intraoperative IVC in shortening operation time (MD: -19.74, 95%CI: -33.31 to -6.17).

Conclusions

There are no discernible effects of intraoperative IVC on PDR, but preoperative IVC, except for very long interval, is an effective adjuvant to PPV for treating PDR.

Therapeutic Hypothermia Inhibits Hypoxia-Induced Cardiomyocyte Apoptosis Via the MiR-483-3p/Cdk9 Axis

Background Therapeutic hypothermia has a beneficial effect on cardiac function after acute myocardial infarction, but the exact mechanism is still unclear. Recent research has suggested that microRNAs participate in acute myocardial infarction to regulate cardiomyocyte survival. This study aimed to explore the ability of hypothermia-regulated microRNA-483-3p (miR-483-3p) to inhibit hypoxia-induced myocardial infarction. Methods and Results Primary cardiomyocytes were cultured under hypoxia at 32 °C to mimic therapeutic hypothermia, and the differentially expressed microRNAs were determined by RNA sequencing. Therapeutic hypothermia recovered hypoxia-induced increases in apoptosis, decreases in ATP levels, and decreases in miR-483-3p expression. Overexpression of miR-483-3p exhibited effects similar to those of therapeutic hypothermia on hypoxia in the treatment of cardiomyocytes to associate with maintaining the mitochondrial membrane potential, and cyclin-dependent kinase 9 (Cdk9) was identified as a target gene with downregulated expression by miR-483-3p. Knockdown of Cdk9 also promoted cardiac survival, ATP production, and mitochondrial membrane potential stability under hypoxia. In vivo, the expression of miR-483-3p and Cdk9 was tested in the cardiac tissue of the mice with acute myocardial infarction, and the expression of miR-483-3p decreased and Cdk9 increased in the region of myocardial infarction. However, miR-483-3p was overexpressed with lentivirus, which suppressed apoptosis, infarct size (miR-483-3p, 22.00±4.04% versus negative control, 28.57±5.44%, P<0.05), and Cdk9 expression to improve cardiac contractility. Conclusions MiR-483-3p antagonizes hypoxia, leading to cardiomyocyte injury by targeting Cdk9, which is a new mechanism of therapeutic hypothermia.

MiR-99a-5p Inhibits the Proliferation and Migration of Human Retinal Microvascular Endothelial Cells by Targeting NOX4

Diabetic retinopathy is one of the common microvascular complications of diabetes, and it is the main cause of vision loss among working-age people. This study interpreted the roles of miR-99a-5p in DR patients and human retinal microvascular endothelial cell (hRMECs) injury induced by high glucose. The expression of miR-99a-5p was detected in patients with NDR, NPDR, and PDR. The indictive impacts of miR-99a-5p were tested by the ROC curve, and the link between miR-99a-5p and clinical information was verified by the Pearson test. HG was used to instruct cell models. The CCK-8 and transwell methods were performed to detect the proliferative and migrated cells. The targeted relationship was explained by luciferase activity. The content of miR-99a-5p was gradually lessened in NPDR and PDR patients. MiR-99a-5p might differentiate DR patients from NDR patients and PDR patients from NPDR patients. The interconnection between miR-99a-5p and clinical factors was endorsed in all DR patients. Overexpression of miR-99a-5p assuaged the abnormality of cell migration and proliferation of hRMECs triggered by HG. NOX4 was a downstream signaling component of miR-99a-5p. In conclusion, MiR-99a-5p protected hRMECs against HG damage, and the miR-99a-5p might be a novel target for diagnosis of DR.

Efficacy of laser photocoagulation plus ranibizumab in patients with diabetic retinopathy and their effect on VEGF

OBJECTIVE

To investigate the efficacy of laser photocoagulation combined with ranibizumab in patients with diabetic retinopathy and their effect on VEGF.

METHODS

The medical records of 98 patients with diabetic retinopathy treated in the First People's Hospital of Linping District from February 2020 to January 2022 were collected for a retrospective analysis. Among them, 48 patients treated with laser photocoagulation were a control group (CG), and another 50 treated with laser photocoagulation combined with ranibizumab were an observation group (OG). The treatment efficacy, best corrected visual acuity (BCVA), central macular concave thickness (CMT), and change in neovascularization area were compared between the two groups. Also, the changes in serum vascular endothelial growth factor (VEGF), homocysteine (HCY), vitamin B12 and folic acid were compared. The adverse effects that occurred with treatment were assessed. The relationship of pre-treatment BCVA, CMT, neovascularization area and VEGF levels with clinical outcomes were observed, and their predictive values were analyzed by receiver operating characteristic (ROC) curve.

RESULTS

The total response rate of patients in the CG was lower than that in the OG (P<0.05). The BCVA, CMT, and neovascularization area were dramatically lower, while vitamin B12 and folic acid were markedly higher in the OG than in the CG after treatment (P<0.05). There was no statistical difference in adverse reactions between the two groups (P>0.05). In patients with effective response, the BCVA, CMT, VEGF and Hcy before treatment were dramatically lower than in those with ineffective response (P<0.05), while the neovascularization area, vitamin B12, and folic acid did not differ between them before treatment (P>0.05). ROC curve analysis revealed that the areas under the curve of BCVA, CMT, VEGF and Hcy were all greater than 0.7 for predicting patient outcomes, and the area under the curve of the combination of the above indexes was 0.945, with a specificity of 92.30% and sensitivity of 88.23%.

CONCLUSION

Laser photocoagulation combined with ranibizumab may provide good therapeutic efficacy in diabetic retinopathy, by effectively improving neovascularization and reducing VEGF levels to control further progression of the lesions.

Effects of microRNAs on angiogenesis in diabetic wounds

Diabetes mellitus is a morbid condition affecting a growing number of the world population, and approximately one third of diabetic patients are afflicted with diabetic foot ulcers (DFU), which are chronic non-healing wounds that frequently progress to require amputation. The treatments currently used for DFU focus on reducing pressure on the wound, staving off infection, and maintaining a moist environment, but the impaired wound healing that occurs in diabetes is a constant obstacle that must be faced. Aberrant angiogenesis is a major contributor to poor wound healing in diabetes and surgical intervention is often necessary to establish peripheral blood flow necessary for healing wounds. Over recent years, microRNAs (miRNAs) have been implicated in the dysregulation of angiogenesis in multiple pathologies including diabetes. This review explores the pathways of angiogenesis that become dysregulated in diabetes, focusing on miRNAs that have been identified and the mechanisms by which they affect angiogenesis.

The role of mesenchymal stem cell-derived EVs in diabetic wound healing

Diabetic foot is one of the most common complications of diabetes, requiring repeated surgical interventions and leading to amputation. In the absence of effective drugs, new treatments need to be explored. Previous studies have found that stem cell transplantation can promote the healing of chronic diabetic wounds. However, safety issues have limited the clinical application of this technique. Recently, the performance of mesenchymal stem cells after transplantation has been increasingly attributed to their production of exocrine functional derivatives such as extracellular vesicles (EVs), cytokines, and cell-conditioned media. EVs contain a variety of cellular molecules, including RNA, DNA and proteins, which facilitate the exchange of information between cells. EVs have several advantages over parental stem cells, including a high safety profile, no immune response, fewer ethical concerns, and a reduced likelihood of embolism formation and carcinogenesis. In this paper, we summarize the current knowledge of mesenchymal stem cell-derived EVs in accelerating diabetic wound healing, as well as their potential clinic applications.

LncRNA SNHG1 targets miR-340-5p/PIK3CA axis to regulate microvascular endothelial cell proliferation, migration, and angiogenesis in DR

Diabetic retinopathy (DR) is a serious long-term complication of diabetes. However, the current treatment of DR is still challenging. We aimed to investigate the role of lncRNA SNHG1/miR-340-5p/PIK3CA in DR and the mechanisms involved. Blood samples from clinical DR patients and healthy subjects were obtained. HRMECs were induced by high glucose for 24 h to establish the DR model. The vector for interfering or overexpressing lncRNA SNHG1, miR-340-5p, and PIK3CA was constructed. LncRNA SNHG1, miR-340-5p, and PIK3CA expressions were detected by qRT-PCR or Western blot. Cell proliferation and migration were detected by CCK-8 and Transwell assays. Blood vessel formation was detected by angiogenesis assay. Dual-luciferase reporter assay tested the interaction of lncRNA SNHG1 with miR-340-5p and miR-340-5p with PIK3CA. RIP measured the binding of miR-340-5p to PIK3CA. In the blood of DR patients and the DR model, lncRNA SNHG1 was increased and miR-340-5p expression was down-regulated. In the DR model, PIK3CA expression was elevated. Downregulation of lncRNA SNHG1 inhibited HRMECs proliferation, migration, and angiogenesis. LncRNA SNHG1 interacted with miR-340-5p, and up-regulation of miR-340-5p inhibited HRMECs proliferation, migration and angiogenesis. The inhibition of cell proliferation, migration, and angiogenesis of HRMECs caused by down-regulation of lncRNA SNHG1 was reversed by knockdown of miR-340-5p. miR-340-5p targeted PIK3CA, and downregulation of PIK3CA inhibited HRMECs proliferation, migration, and angiogenesis. The inhibition of HRMECs proliferation, migration and angiogenesis caused by down-regulation of lncRNA SNHG1 could be reversed by overexpression of PIK3CA. LncRNA SNHG1 targeted miR-340-5p/PIK3CA axis to regulate microvascular endothelial cell proliferation, migration, and angiogenesis in DR.

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.

DNA methylation in diabetic retinopathy: pathogenetic role and potential therapeutic targets

Background

Diabetic retinopathy (DR), a specific neuron-vascular complication of diabetes, is a major cause of vision loss among middle-aged people worldwide, and the number of DR patients will increase with the increasing incidence of diabetes. At present, it is limited in difficult detection in the early stages, limited treatment and unsatisfactory treatment effects in the advanced stages.

Main body

The pathogenesis of DR is complicated and involves epigenetic modifications, oxidative stress, inflammation and neovascularization. These factors influence each other and jointly promote the development of DR. DNA methylation is the most studied epigenetic modification, which has been a key role in the regulation of gene expression and the occurrence and development of DR. Thus, this review investigates the relationship between DNA methylation and other complex pathological processes in the development of DR. From the perspective of DNA methylation, this review provides basic insights into potential biomarkers for diagnosis, preventable risk factors, and novel targets for treatment.

Conclusion

DNA methylation plays an indispensable role in DR and may serve as a prospective biomarker of this blinding disease in its relatively early stages. In combination with inhibitors of DNA methyltransferases can be a potential approach to delay or even prevent patients from getting advanced stages of DR.

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.

Berberis dictyophylla F. inhibits angiogenesis and apoptosis of diabetic retinopathy via suppressing HIF-1α/VEGF/DLL-4/Notch-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Xiao Bopi (XBP, སྐྱེར་བའི་བར་ཤུན།), as a classical Tibetan medicinal plant in China, which derived from the stem bark of Berberis dictyophylla F., has the function of "clearing heat and decreasing mKhris-pa". And it traditionally is utilized to treat the diabetes mellitus and its complications, such as diabetic retinopathy (DR). However, its underlying mechanisms remain unclear.

AIM OF THE STUDY

The purpose of this study aimed to explore the microvascular protection of water extract of XBP against the spontaneous retinal damage of db/db mice. Meanwhile, the underlying mechanisms of XBP on angiogenesis and apoptosis were further interpreted.

MATERIALS AND METHODS

We firstly used high-performance liquid chromatography to detected the representative chemical ingredients in the water extract of XBP. The DR model of db/db mice was then randomly divided into five groups: model group, calcium dobesilate (0.23 g/kg) group, and the water extract of XBP (0.375, 0.75 and 1.5 g/kg, respectively) groups. After 8 weeks of continuous administration, the parameters including body weight, fasting blood glucose, oral glucose tolerance test and insulin tolerance test were measured. The pathological changes and abnormal angiogenesis of the retina were detected by optical coherence tomography, HE, periodic acid-Schiff staining and transmission electron microscopy. Simultaneously, molecular docking was used to predict the potential connections between representative ingredients in XBP and angiogenesis/apoptosis-related proteins. The level of angiogenesis-related proteins and gene hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth (VEGF), delta-like ligand 4 (DLL-4) and Notch-1 were estimated by immunofluorescence analyses and real time-PCR. Further, TUNEL staining and immunofluorescence analyses were performed to investigate the apoptotic phenomenon and the expression of Bax, Bcl-2, Apaf-1, Cyto-c and cleaved caspase-3 and cleaved caspase-9 in the retina.

RESULTS

Phytochemical analysis revealed that magnoflorine, jatrorrhizine, palmatine and berberine were principally representative ingredients in XBP. The results demonstrated that XBP effectively increased glucose tolerance and insulin sensitivity, whereas no effect on body weight of DR mice. Moreover, retinal thickening, pathological and retinal ultrastructure changes in DR mice were evidently ameliorated by XBP. The molecular docking results demonstrated that the main components of XBP and the protein of angiogenesis and apoptosis had a potential bind. XBP restrained the gene and protein levels of HIF-1α, VEGF, DLL-4 and Notch-1 in retina. Additionally, the TUNEL-positive cell rate and the down-regulated proteins of Bax, Apaf-1, Cyto-c, cleaved Caspase-3 and cleaved Caspase 9 and increased Bcl-2 level were revised by XBP.

CONCLUSIONS

To sum up, the results suggested that XBP against DR could attribute to alleviating angiogenesis and apoptosis by suppressing the HIF-1α/VEGF/DLL-4/Notch-1 pathway. This evidence sheds a new light on the potential mechanisms of XBP in the treatment of DR.

Advanced glycation end products induce Aβ1-42 deposition and cognitive decline through H19/miR-15b/BACE1 axis in diabetic encephalopathy

OBJECTIVE

Diabetic encephalopathy (DE), a chronic complication of diabetes, is characterized by decline of cognitive function. The molecular mechanism of DE remains unclear. The purpose of this study is to evaluate the roles of advanced glycation end products (AGEs) in the pathogenesis of DE and investigate its underlying mechanisms in this process.

METHODS

DE rats were developed by incorporating a high-fat diet and streptozotocin injection followed by the Morris Water Maze test. HT-22 cells were used to mimic the in vitro neuronal injuries of DE. Expression levels of long non-coding RNA H19, miR-15b and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) mRNA in the hippocampus of DE rats or HT-22 cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The levels of BACE1 proteins were analyzed by western blotting or immunohistochemical staining. The contents of Aβ_1-42 in supernatant of the cell culture were analyzed by enzyme-linked immu-nosorbent assay (ELISA). The relationship between H19 or BACE1 and miR-15b was verified with dual-luciferase reporter assay.

RESULTS

We found that the accumulation of Aβ_1-42 and the phosphorylation of Tau (Ser404) were increased in the hippocampus CA3 regionof DE rats. MiR-15b was downregulated while H19 and BACE1 were upregulated in the hippocampus CA3 regionof DE rats and AGEs-treated HT-22 cells. The expression of BACE1 protein was negatively regulated by miR-15b at the post-transcriptional level in HT-22 cells. In vivo, administration of miR-15b mimics by the intranasal delivery markedly decreased the BACE1 protein in hippocampal CA3 region and improved the cognitive decline in DE rats. Besides, the luciferase activity assay confirmed the binding site of miR-15b to both the 3'-untranslated region (3'-UTR) of BACE1 mRNA and H19. Then, miR-15b inhibitor reversed H19 knockdown-mediated decrease of Aβ_1-42 level in AGEs-treated HT-22 cells.

CONCLUSION

These results suggested that AGEs induced Aβ_1-42 deposition andcognitive decline through H19/miR-15b/ BACE1 axis in DE.

Wnt inhibitory factor 1 ameliorated diabetic retinopathy through the AMPK/mTOR pathway-mediated mitochondrial function

Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus and will lead to visual impairment. We aim to explore the effects and mechanisms of wnt inhibitory factor 1 (WIF1) in the progression of DR. To establish DR in vitro and in vivo, human retinal pigment epithelium (RPE) cell line ARPE-19 was treated with high-glucose (HG) and diabetic mice models were induced by streptozotocin (STZ), respectively. Different dose of recombinant WIF1 protein was used to treat DR. qRT-PCR and western blotting results demonstrated that WIF1 was downregulated, while VEGFA was upregulated in HG-induced ARPE-19 cells. WIF1 overexpression promoted cell migration. The ARPE-19 cells culture medium treated with WIF1 inhibited retinal endothelial cell tube formation and downregulated VEGFA expression. Moreover, WIF1 decreased the levels of ROS and MDA, while increasing the activity of SOD and GPX. WIF1 increased the ΔΨm in the mitochondria and downregulated the expression of mitochondrial autophagy-related proteins including Parkin, Pink1, LC3-II/LC3-I ratio, cleaved caspase 3, and cyt-c, which ameliorated mitochondrial dysfunction. The in vivo studies further demonstrated the consistent effects of WIF1 in STZ-induced mice. Taken together, WIF1 ameliorated mitochondrial dysfunction in DR by downregulating the AMPK/mTOR pathway.

CircRNA SCMH1 regulates the miR-200a-3p/ZEB1 signaling axis to promote diabetes-induced retinal epithelial-mesenchymal transition

Diabetic retinopathy (DR) is one of the common systemic complications of diabetes. Epithelial-mesenchymal transition (EMT) is required for DR progression. Previous studies have explored that circular RNAs (circRNAs) are crucial for DR development. Herein, we focused on the biological functions of circSCMH1 in DR. RT-qPCR determined the expression of circSCMH1, miR-200a-3p and ZEB1. EMT-related proteins were measured by Western blot. Gene combinations were validated by RIP and dual luciferase reporter assays. CCK-8, EdU, TUNEL staining and Transwell analysis were used to assess the cellular function. FISH analysis assessed the localization of circSCMH1 and miR-200a-3p. HE staining was used to detect retinal structures in a mouse DR model. High-glucose (HG) significantly increased circSCMH1 expression in ARPE-19 cells. Additionally, circSCMH1 silencing repressed proliferation, migration, and EMT in HG cells. Mechanistically, circSCMH1 positively regulated ZEB1 expression via targeting miR-200a-3p. Furthermore, circSCMH1 was observed to induce HG cell growth and EMT by regulating the miR-200a-3p/ZEB1 axis. Finally, we verified that downregulation of circSCMH1 or ZEB1 alleviated EMT in the retina of diabetic mice. These findings have implications for new therapeutic targets for DR.

miR-142 Targets TIM-1 in Human Endothelial Cells: Potential Implications for Stroke, COVID-19, Zika, Ebola, Dengue, and Other Viral Infections

T-cell immunoglobulin and mucin domain 1 (TIM-1) has been recently identified as one of the factors involved in the internalization of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human cells, in addition to angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), neuropilin-1, and others. We hypothesized that specific microRNAs could target TIM-1, with potential implications for the management of patients suffering from coronavirus disease 2019 (COVID-19). By combining bioinformatic analyses and functional assays, we identified miR-142 as a specific regulator of TIM-1 transcription. Since TIM-1 has been implicated in the regulation of endothelial function at the level of the blood-brain barrier (BBB) and its levels have been shown to be associated with stroke and cerebral ischemia-reperfusion injury, we validated miR-142 as a functional modulator of TIM-1 in human brain microvascular endothelial cells (hBMECs). Taken together, our results indicate that miR-142 targets TIM-1, representing a novel strategy against cerebrovascular disorders, as well as systemic complications of SARS-CoV-2 and other viral infections.

Inward rectifier potassium (Kir) channels in the retina: living our vision

Channel proteins are vital for conducting ions throughout the body and are especially relevant to retina physiology. Inward rectifier potassium (Kir) channels are a class of K+ channels responsible for maintaining membrane potential and extracellular K+ concentrations. Studies of the KCNJ gene (that encodes Kir protein) expression identified the presence of all of the subclasses (Kir 1-7) of Kir channels in the retina or retinal-pigmented epithelium (RPE). However, functional studies have established the involvement of the Kir4.1 homotetramer and Kir4.1/5.1 heterotetramer in Müller glial cells, Kir2.1 in bipolar cells, and Kir7.1 in the RPE cell physiology. Here, we propose the potential roles of Kir channels in the retina based on the physiological contributions to the brain, pancreatic, and cardiac tissue functions. There are several open questions regarding the expressed KCNJ genes in the retina and RPE. For example, why does not the Kir channel subtype gene expression correspond with protein expression? Catching up with multiomics or functional "omics" approaches might shed light on posttranscriptional changes that might influence Kir subunit mRNA translation within the retina that guides our vision.

The pathophysiological mechanisms underlying diabetic retinopathy

Diabetic retinopathy (DR) is the most common complication of diabetes mellitus (DM), which can lead to visual impairment and even blindness in severe cases. DR is generally considered to be a microvascular disease but its pathogenesis is still unclear. A large body of evidence shows that the development of DR is not determined by a single factor but rather by multiple related mechanisms that lead to different degrees of retinal damage in DR patients. Therefore, this article briefly reviews the pathophysiological changes in DR, and discusses the occurrence and development of DR resulting from different factors such as oxidative stress, inflammation, neovascularization, neurodegeneration, the neurovascular unit, and gut microbiota, to provide a theoretical reference for the development of new DR treatment strategies.

Identifying gene variants underlying the pathogenesis of diabetic retinopathy based on integrated genomic and transcriptomic analysis of clinical extreme phenotypes

Diabetic retinopathy (DR) is a common complication and the leading cause of blindness in patients with type 2 diabetes. DR has been shown to be closely correlated with blood glucose levels and the duration of diabetes. However, the onset and progression of DR also display clinical heterogeneity. We applied whole-exome sequencing and RNA-seq approaches to study the gene mutation and transcription profiles in three groups of diabetic patients with extreme clinical phenotypes in DR onset, timing, and disease progression, aiming to identify genetic variants that may play roles in the pathogenesis of DR. We identified 23 putatively pathogenic genes, and ingenuity pathway analysis of these mutated genes reveals their functional association with glucose metabolism, diabetic complications, neural system activity, and dysregulated immune responses. In addition, ten potentially protective genes were also proposed. These findings shed light on the mechanisms underlying the pathogenesis of DR and may provide potential targets for developing new strategies to combat DR.

miR-146a suppresses the expression of vascular endothelial growth factor and inflammatory responses in diabetic retinopathy

This study was designed to explore the role of miR-146a in diabetic retinopathy (DR). 30 healthy control (HC), 50 patients with type 2 diabetes mellitus, and 48 DR patients were enrolled. Blood was collected and levels of miR-146a expression, vascular endothelial growth factor (VEGF), and three inflammatory cytokines (NF-κB, IL-1β, and TNF-α) were detected. Moreover, ARPE-19 cells were treated with miR-146a mimic or inhibitor in the presence of high glucose to evaluate its effect in vitro. DR patients had the lowest level of miR-146a and the highest level of VEGF as well as the most severe inflammation among the three groups. In addition, the miR-146a level was negatively correlated with the expression of VEGF and three inflammatory cytokines, respectively in DR patients. Moreover, VEGF expression was positively correlated with these three inflammatory cytokines in DR patients. In summary, miR-146a could inhibit VEGF expression and inflammation in DR.

The Diagnostic Value of Circulating VEGF in Diabetic Retinopathy in Asia: A Systematic Review and Meta-analysis

PURPOSE

Vascular endothelial growth factor (VEGF) has obvious clinical value in diabetes, but the conclusions on the diagnostic value of diabetic retinopathy (DR) are not consistent. This study aims to comprehensively evaluate the accuracy of circulating VEGF in the diagnosis of DR in the Asian population by a method of meta-analysis.

METHODS

PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and China Wanfang Databases were searched for relevant studies on the diagnostic value of VEGF for DR in Asia up to November 2021. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and areas under the curve (AUC) were calculated by Stata 15.0 software.

RESULTS

After screening, eight eligible studies were enrolled, including 547 patients with DR. The results of the meta-analysis showed that the pooled DOR, sensitivity, specificity, PLR, and NLR were 31.67 (95%CI: 13.55 ~ 74.05), 0.86 (95%CI: 0.74 ~ 0.93), 0.84 (95%CI: 0.80 ~ 0.87), 5.33 (95%CI: 4.09 ~ 6.93), 0.17 (95%CI: 0.09 ~ 0.32), respectively. The AUC was 0.86 (95%CI: 0.82 ~ 0.89).

CONCLUSION

Circulating VEGF has a good diagnostic value in DR in the Asian population, with the potential to be an early diagnostic marker for DR.