MiR-126 targets IL-17A to enhance proliferation and inhibit apoptosis in high-glucose-induced human retinal endothelial cells

Interleukin-17A in diabetic retinopathy: The crosstalk of inflammation and angiogenesis

Diabetic retinopathy (DR) is a severe ocular complication of diabetes which can leads to irreversible vision loss in its late-stage. Chronic inflammation results from long-term hyperglycemia contributes to the pathogenesis and progression of DR. In recent years, the interleukin-17 (IL-17) family have attracted the interest of researchers. IL-17A is the most widely explored cytokine in IL-17 family, involved in various acute and chronic inflammatory diseases. Growing body of evidence indicate the role of IL-17A in the pathogenesis of DR. However, the pro-inflammatory and pro-angiogenic effect of IL-17A in DR have not hitherto been reviewed. Gaining an understanding of the pro-inflammatory role of IL-17A, and how IL-17A control/impact angiogenesis pathways in the eye will deepen our understanding of how IL-17A contributes to DR pathogenesis. Herein, we aimed to thoroughly review the pro-inflammatory role of IL-17A in DR, with focus in how IL-17A impact inflammation and angiogenesis crosstalk.

MicroRNA-126 (MiR-126): key roles in related diseases

In eukaryotes such as humans, some non-coding single-stranded RNAs (ncRNAs) help to regulate the pre- and post-transcriptional expression of certain genes, which in turn control many important physiological processes, such as cell proliferation, distinctions, invasion, angiogenesis, and embryonic development. microRNA-126 is an important member of these miRNAs that can be directly or indirectly involved in the control of angiogenesis. Recently, numerous studies have expounded that microRNA-126 can inhibit or promote angiogenesis as well as attenuate inflammatory responses through complex molecular mechanisms. As such, it serves as a biomarker or potential therapeutic target for the prediction, diagnosis, and treatment of relevant diseases. In this review, we present the advancements in research regarding microRNA-126's role in the diagnosis and treatment of related diseases, aiming to provide innovative therapeutic options for the diagnosis and treatment of clinically relevant diseases.

Meta-analysis of the relationship between ocular and peripheral serum IL-17A and diabetic retinopathy

Purpose

A systematic evaluation and Meta-analysis were performed to determine the relationship between IL-17A levels in ocular aqueous and peripheral venous serum samples and diabetic retinopathy (DR).

Methods

PubMed, Embase, Web of Science, and CNKI databases were searched from the time of library construction to 2023-09-20.The results were combined using a random-effects model, sensitivity analyses were performed to determine whether the arithmetic was stable and reliable, and subgroup analyses were used to look for possible sources of heterogeneity.

Results

A total of 7 case-control studies were included. The level of IL-17A was higher in the Nonproliferative DR(NPDR) group than in the Non-DR(NDR) group [SMD=2.07,95%CI(0.45,3.68),P=0.01], and the level of IL-17A in the proliferating DR(PDR) group was higher than that of the NDR group [SMD=4.66,95%CI(1.23,8.08),P<0.00001]. IL-17A levels in peripheral serum and atrial fluid were significantly higher in NPDR and PDR patients than in non-DR patients in subgroup analyses, and detection of peripheral serum IL-17A concentrations could help to assess the risk of progression from NPDR to PDR. Sensitivity analyses suggested that the results of the random-effects arithmetic were stable and reliable. Subgroup analyses based on assay method and sample source showed that the choice of these factors would largely influence the relationship between IL-17A levels and DR.

Conclusion

Elevated peripheral serum and ocular aqueous humor IL-17A levels in diabetic patients are associated with the risk of DR, IL-17A may serve as a potential predictor or therapeutic target for DR, and IL-17A may be an important predictor of inflammation for the progression of NPDR to PDR.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024532900.

Mechanistic insights into the alterations and regulation of the AKT signaling pathway in diabetic retinopathy

In the early stages of diabetic retinopathy (DR), diabetes-related hyperglycemia directly inhibits the AKT signaling pathway by increasing oxidative stress or inhibiting growth factor expression, which leads to retinal cell apoptosis, nerve proliferation and fundus microvascular disease. However, due to compensatory vascular hyperplasia in the late stage of DR, the vascular endothelial growth factor (VEGF)/phosphatidylinositol 3 kinase (PI3K)/AKT cascade is activated, resulting in opposite levels of AKT regulation compared with the early stage. Studies have shown that many factors, including insulin, insulin-like growth factor-1 (IGF-1), VEGF and others, can regulate the AKT pathway. Disruption of the insulin pathway decreases AKT activation. IGF-1 downregulation decreases the activation of AKT in DR, which abrogates the neuroprotective effect, upregulates VEGF expression and thus induces neovascularization. Although inhibiting VEGF is the main treatment for neovascularization in DR, excessive inhibition may lead to apoptosis in inner retinal neurons. AKT pathway substrates, including mammalian target of rapamycin (mTOR), forkhead box O (FOXO), glycogen synthase kinase-3 (GSK-3)/nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor kappa-B (NF-κB), are a research focus. mTOR inhibitors can delay or prevent retinal microangiopathy, whereas low mTOR activity can decrease retinal protein synthesis. Inactivated AKT fails to inhibit FOXO and thus causes apoptosis. The GSK-3/Nrf2 cascade regulates oxidation and inflammation in DR. NF-κB is activated in diabetic retinas and is involved in inflammation and apoptosis. Many pathways or vital activities, such as the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) and mitogen-activated protein kinase (MAPK) signaling pathways, interact with the AKT pathway to influence DR development. Numerous regulatory methods can simultaneously impact the AKT pathway and other pathways, and it is essential to consider both the connections and interactions between these pathways. In this review, we summarize changes in the AKT signaling pathway in DR and targeted drugs based on these potential sites.

The role of microRNAs in pathophysiology and diagnostics of metabolic complications in obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is one of the most common sleep disorders, which is characterized by recurrent apneas and/or hypopneas occurring during sleep due to upper airway obstruction. Among a variety of health consequences, OSA patients are particularly susceptible to developing metabolic complications, such as metabolic syndrome and diabetes mellitus type 2. MicroRNAs (miRNAs) as epigenetic modulators are promising particles in both understanding the pathophysiology of OSA and the prediction of OSA complications. This review describes the role of miRNAs in the development of OSA-associated metabolic complications. Moreover, it summarizes the usefulness of miRNAs as biomarkers in predicting the aforementioned OSA complications.

Global trends and performances in diabetic retinopathy studies: A bibliometric analysis

Objective

The objective of this study is to conduct a comprehensive bibliometric analysis to identify and evaluate global trends in diabetic retinopathy (DR) research and visualize the focus and frontiers of this field.

Methods

Diabetic retinopathy-related publications from the establishment of the Web of Science (WOS) through 1 November 2022 were retrieved for qualitative and quantitative analyses. This study analyzed annual publication counts, prolific countries, institutions, journals, and the top 10 most cited literature. The findings were presented through descriptive statistics. VOSviewer 1.6.17 was used to exhibit keywords with high frequency and national cooperation networks, while CiteSpace 5.5.R2 displayed the timeline and burst keywords for each term.

Results

A total of 10,709 references were analyzed, and the number of publications continuously increased over the investigated period. America had the highest h-index and citation frequency, contributing to the most influence. China was the most prolific country, producing 3,168 articles. The University of London had the highest productivity. The top three productive journals were from America, and Investigative Ophthalmology Visual Science had the highest number of publications. The article from Gulshan et al. (2016; co-citation counts, 2,897) served as the representative and symbolic reference. The main research topics in this area were incidence, pathogenesis, treatment, and artificial intelligence (AI). Deep learning, models, biomarkers, and optical coherence tomography angiography (OCTA) of DR were frontier hotspots.

Conclusion

Bibliometric analysis in this study provided valuable insights into global trends in DR research frontiers. Four key study directions and three research frontiers were extracted from the extensive DR-related literature. As the incidence of DR continues to increase, DR prevention and treatment have become a pressing public health concern and a significant area of research interest. In addition, the development of AI technologies and telemedicine has emerged as promising research frontiers for balancing the number of doctors and patients.

Roles of physical exercise-induced MiR-126 in cardiovascular health of type 2 diabetes

Although physical activity is widely recommended for preventing and treating cardiovascular complications of type 2 diabetes mellitus (T2DM), the underlying mechanisms remain unknown. MicroRNA-126 (miR-126) is an angiogenetic regulator abundant in endothelial cells (ECs) and endothelial progenitor cells (EPCs). It is primarily involved in angiogenesis, inflammation and apoptosis for cardiovascular protection. According to recent studies, the levels of miR-126 in the myocardium and circulation are affected by exercise protocol. High-intensity interval training (HIIT) or moderate-and high-intensity aerobic exercise, whether acute or chronic, can increase circulating miR-126 in healthy adults. Chronic aerobic exercise can effectively rescue the reduction of myocardial and circulating miR-126 and vascular endothelial growth factor (VEGF) in diabetic mice against diabetic vascular injury. Resistance exercise can raise circulating VEGF levels, but it may have a little influence on circulating miR-126. The Several targets of miR-126 have been suggested for cardiovascular fitness, such as sprouty-related EVH1 domain-containing protein 1 (SPRED1), phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2), vascular cell adhesion molecule 1 (VCAM1), high-mobility group box 1 (HMGB1), and tumor necrosis factor receptor-associated factor 7 (TRAF7). Here, we present a comprehensive review of the roles of miR-126 and its downstream proteins as exercise mechanisms, and propose that miR-126 can be applied as an exercise indicator for cardiovascular prescriptions and as a preventive or therapeutic target for cardiovascular complications in T2DM.

Interleukin-17A attenuates photoreceptor cell apoptosis in streptozotocin-induced diabetic mouse model

Diabetic retinopathy (DR) represents an important microvascular complication of diabetes, which is the top etiology of vision impairment worldwide. Although interleukin (IL)-17A is increasingly implicated in DR development, the underlying cellular mechanisms remain poorly defined. This work aims to evaluate IL-17A levels in the retina of streptozotocin (STZ)-induced diabetic mice and elucidate their potential roles. We found IL-17A was upregulated in diabetic retina after intraperitoneal injection of STZ and high-glucose (HG)-cultured primary Müller cells. IL-17A knockout (IL-17A^−/−) downregulated glial fibrillary acidic protein (GFAP) and inhibited the conversion of proneurotrophin-3 (proNT-3) to mature NT-3 in retinal specimens from diabetic mice as well as in Müller cells cultured under HG conditions. Induced apoptosis and upregulated Bax and cleaved caspase-3 were observed in retinal specimens from IL-17A^−/− diabetic mice and photoreceptor (661 W) cells after co-culture with IL-17A^−/− Müller cells. Moreover, RNA interference-induced gene silencing of tyrosine kinase C receptor (TrkC) in 661 W cells reversed the anti-apoptotic effect of IL-17A under HG conditions. Taken together, our findings suggest that IL-17A/NT-3/TrkC axis regulation suppresses apoptosis in photoreceptor cells, providing a new treatment strategy for DR.

Decreased Levels of miR-126 and miR-132 in Plasma and Vitreous Humor of Non-Proliferative Diabetic Retinopathy Among Subjects with Type-2 Diabetes Mellitus

PURPOSE

Diabetic retinopathy (DR), the leading cause of blindness among working adults, is an urgent public health problem as diabetes mellitus (DM) is increasing at an alarming rate. Hyperglycemia-induced endothelial dysfunction is the principal contributing factor leading to the development of microangiopathy. Altered levels of microRNA (miR), the negative regulator of protein-coding genes, have been observed and considered to be markers for DR. Present study aimed to find out whether miR levels in plasma could be effective biomarkers to differentiate between type 2 diabetes mellitus (T2DM) with non-proliferative retinopathy (NPDR) from T2DM with no-DR (DNR).

METHODS

We recruited 50 T2DM subjects comprising 31 NPDR and 19 DNR individuals. Surrogate markers of systemic oxidative stress and vascular endothelial growth factor (VEGF) were measured in plasma. Levels of miR-126 and miR-132 were determined in plasma and vitreous fluid using real-time PCR.

RESULTS

We observed that levels of miR-126 and miR-132 were decreased in NPDR subjects in comparison to DNR. Plasma levels of miRs were inversely correlated with secreted levels of VEGF and oxidative stress marker. The levels of these miRs showed discriminating ability between NPDR and DNR.

CONCLUSION

Circulating miRs 126 and 132 in plasma or vitreous may serve as biomarkers for early diabetic retinopathy risk prediction, provided validated in a larger cohort and other forms of retinal vasculopathy or retinopathy in the future.

LE-MDCAP: A Computational Model to Prioritize Causal miRNA-Disease Associations

MicroRNAs (miRNAs) are associated with various complex human diseases and some miRNAs can be directly involved in the mechanisms of disease. Identifying disease-causative miRNAs can provide novel insight in disease pathogenesis from a miRNA perspective and facilitate disease treatment. To date, various computational models have been developed to predict general miRNA-disease associations, but few models are available to further prioritize causal miRNA-disease associations from non-causal associations. Therefore, in this study, we constructed a Levenshtein-Distance-Enhanced miRNA-disease Causal Association Predictor (LE-MDCAP), to predict potential causal miRNA-disease associations. Specifically, Levenshtein distance matrixes covering the sequence, expression and functional miRNA similarities were introduced to enhance the previous Gaussian interaction profile kernel-based similarity matrix. LE-MDCAP integrated miRNA similarity matrices, disease semantic similarity matrix and known causal miRNA-disease associations to make predictions. For regular causal vs. non-disease association discrimination task, LF-MDCAP achieved area under the receiver operating characteristic curve (AUROC) of 0.911 and 0.906 in 10-fold cross-validation and independent test, respectively. More importantly, LE-MDCAP prominently outperformed the previous MDCAP model in distinguishing causal versus non-causal miRNA-disease associations (AUROC 0.820 vs. 0.695). Case studies performed on diabetic retinopathy and hsa-mir-361 also validated the accuracy of our model. In summary, LE-MDCAP could be useful for screening causal miRNA-disease associations from general miRNA-disease associations.

Paeonol inhibits human lung cancer cell viability and metastasis in vitro via miR-126-5p/ZEB2 axis

Paeonol exerted an effect in lung cancer, but the underlying mechanism remained vague. In this research, we assessed the effects of Paeonol and microRNA (miR)-126-5p on the viability, migration, invasion, and epithelial-mesenchymal transition (EMT) of lung cancer cells. Lung cancer cells and BEAS-2B cells were treated with Paeonol, and viability was detected by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay. The migration and invasion of lung cancer cells after treatment with Paeonol at 40 μg/mL or 80 μg/mL were detected by wound healing assay and Transwell assay, respectively. The effects of Paeonol on transforming growth factor-β1 (TGF-β1)-induced EMT and relative expressions of EMT-related proteins were determined using Western blot. The target gene of miR-126-5p and the binding sites between them were predicted by TargetScan, and confirmed using dual-luciferase reporter assay. Relative expressions of miR-126-5p, its target gene and EMT-related proteins were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Rescue assay was performed to analyze the relation between Paeonol and miR-126-5p. Paeonol down-regulated cell viability and inhibited migration, invasion and TGF-β1-induced EMT while up-regulating miR-126-5p expression in lung cancer cells as the dose increased. However, miR-126-5p inhibitor could reverse the effect of Paeonol. ZEB2 was the target gene of miR-126-5p, and silencing ZEB2 expression reversed the effects of miR-126-5p downregulation. Paeonol also regulated the expression of ZEB2 in lung cancer cells, and this regulation depends on the regulation of miR-126-5p. Paeonol inhibits human lung cancer cell viability and metastasis via the miR-126-5p/ZEB2 axis, and could be adopted as a potential agent for lung cancer treatment.

Preconceptional Immunization Can Modulate Offspring Intrathymic IL-17-Producing γδT Cells with Epigenetic Implications Mediated by microRNAs

The mechanisms through which maternal immunization can modulate offspring thymic maturation of lymphocytes are not fully understood. Here, we aimed to evaluate whether maternal OVA-immunization can inhibit the maturation of IL-17-producing γδT cells in offspring thymus, and if this mechanism has epigenetic implications mediated by microRNAs (miRNAs) expression. Wild-type (WT) C57BL/6 females were immunized with OVA in Alum or Alum alone and were mated with normal WT males. Evaluating their offspring thymus at 3 or 20 days old (d.o.), we observed that maternal OVA immunization could inhibit the thymic frequency of offspring CD27- and IL-17+ γδT cells at the neonatal and until 20 days old. Furthermore, we evaluated the expression of function-related γ and δ variable γδTCR chains (Vγ1, Vγ2, Vγ3, Vδ4, and Vδ6.3), observing that maternal OVA-immunization inhibits Vγ2 chains expression. The small RNAs (sRNAs), particularly miRNAs, and messenger RNAs (mRNA) expression profiles by pools of thymus tissue samples (from 9 to 11 mice) from offspring OVA-immunized or Alum-immunized mothers were analyzed via Illumina sequencing platform and bioinformatics approaches. Using a fold change >4, our results showed that seven miRNAs (mmu-miR-126a-3p, 101a-3p, 744-3p,142-5p, 15a-5p, 532-5p, and 98-5p) were differentially expressed between both groups. Ten target genes were predicted to interact with the seven selected miRNAs. There were no enriched categories of gene ontology functional annotation and pathway enrichment analysis for the target genes. Interestingly, four of the identified miRNAs (mmu-miR-15a, mmu-miR-101 mmu-miR-126, and mmu-miR-142) are related to IL-17 production. Our data is of significance because we demonstrate that maternal immunization can modulate offspring thymic maturation of IL-17-producing γδT cells possibly by an epigenetic mechanism mediated by miRNAs.

miR-126-5p regulates H9c2 cell proliferation and apoptosis under hypoxic conditions by targeting IL-17A

Accumulating evidence has indicated that microRNAs (miRNAs/miRs) regulate the occurrence and development of various diseases, including diabetes, osteoporosis and cardiovascular conditions. However, the role of miRNAs in acute myocardial infarction (AMI) is not completely understood. The present study aimed to evaluate the therapeutic efficacy and mechanisms underlying the effects of miR-126-5p on H9c2 cell proliferation and apoptosis by targeting interleukin (IL)-17A. A total of 40 patients with AMI and 40 healthy volunteers were recruited in the present study and the expression levels of serum miR-126-5p and IL-17A were determined. Following confirmation that IL-17A was a target of miR-126-5p via a dual-luciferase reporter assay, H9c2 cells were exposed to hypoxic conditions. H9c2 cell viability and apoptosis were subsequently assessed. Additionally, the protein expression levels of apoptosis-associated proteins were detected following transfection. Compared with healthy individuals, miR-126-5p expression was significantly decreased in the serum samples of patients with AMI, whereas IL-17A, the target of miR-126-5p, was significantly increased. Following hypoxic treatment, miR-126-5p overexpression enhanced H9c2 cell viability compared with the NC group, which was subsequently reversed following co-transfection with pcDNA3.1-IL-17A. Additionally, the results indicated that hypoxia-induced H9c2 cell apoptosis was significantly reduced following transfection with miR-126-5p mimics via the PI3K/AKT signaling pathway compared with the NC group. The present study indicated that miR-126-5p may serve as a novel miRNA that regulates H9c2 cell viability and apoptosis by targeting IL-17A under hypoxic conditions. Therefore, miR-126-5p may serve as a crucial biomarker for the diagnosis of AMI.