Profiling and functional analysis of differentially expressed circular RNAs in high glucose-induced human umbilical vein endothelial cells

CircRNA: A new target for ischemic stroke

Ischemic stroke, a clinical emergency and disease with a poor prognosis, has a negative impact on the survival index of patients. It is frequently precipitated by a multitude of risk factors, including trauma. Currently, there is a paucity of predictive indicators for early intervention. As stable and abundant RNA in the body, circRNAs play a regulatory role in miRNAs and proteins, which affect the occurrence and development of diseases. Moreover, circRNAs can serve as predictors of clinical diseases. Several studies have demonstrated that circRNAs play pivotal roles in numerous aspects of ischemic stroke. Consequently, circRNAs have emerged as key areas of investigation in the field of ischemic stroke.

Endothelial cells derived extracellular vesicles promote diabetic arterial calcification via circ_0008362/miR-1251-5p/Runx2 axial

INTRODUCTION

Arterial calcification, an independent predictor of cardiovascular events, increases morbidity and mortality in patients with diabetes mellitus (DM), but its mechanisms remain unclear. Extracellular vesicles (EVs) play an important role in intercellular communication. The study investigates the role and potential mechanisms of EVs derived from endothelial cells (ECs) in regulating vascular smooth muscle cell (VSMC) calcification under high glucose (HG) condition, with a goal of developing effective prevention and treatment strategies for diabetic arterial calcification.

RESULTS

The results showed that EVs derived from HG induced ECs (ECHG-EVs) exhibited a bilayer structure morphology with a mean diameter of 74.08 ± 31.78 nm, expressing EVs markers including CD9, CD63 and TSG101, but not express calnexin. ECHG-EVs was internalized by VSMCs and induced VSMC calcification by increasing Runx2 expression and mineralized nodule formation. The circ_0008362 was enriched in ECHG-EVs, and it can be transmitted to VSMCs to promote VSMC calcification both in vitro and in vivo. Mechanistically, miR-1251-5p might be one of the targets of circ_0008362 and they were co-localization in the cytoplasm of VSMCs. Runx2 was identified as the downstream target of miR-1251-5p, and circ_0008362 acted as a sponge, enhancing Runx2 expression and then promoted VSMC calcification. Besides, circ_0008362 could directly interact with Runx2 to aggravate VSMC calcification. Notably, DiR-labelled ECHG-EVs was detected in the vessels of mice. Meanwhile, the level of circ_0008362 and Runx2 were increased significantly, while the expression of miR-1251-5p was decreased significantly in calcified artery tissues of mice. However, inhibiting the release of EVs by GW4869 attenuated arterial calcification in diabetic mice. Finally, the level of circulation of plasma EVs circ_0008362 was significantly higher in patients with DM compared with normal controls. Elevated levels of plasma EVs circ_0008362 were associated with more severe coronary and aorta artery calcification in patients with DM.

CONCLUSIONS

Our findings suggested that circ_0008362 was enriched in EVs derived from ECs and promoted VSMC calcification under HG conditions, both by sponging miR-1251-5p to upregulate Runx2 expression and through direct interaction with Runx2. Furthermore, elevated levels of plasma EVs circ_0008362 were associated with more severe coronary and aorta artery calcification in patients with DM. These results may serve as a potential prevention and therapeutic target for diabetic arterial calcification.

Hsa_circ_0008360 promotes high glucose-induced damage in HK-2 cells via miR-346/WNT2B axis

BACKGROUND

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease worldwide. Recent researches have shown that circular RNAs (circRNAs) could affect the progress of DN, but the mechanism is still indistinct. In this work, we explored the roles of hsa_circ_0008360 in DN.

METHODS

The levels of hsa_circ_0008360, microRNA-346 (miR-346) and Winglesstype family member 2B (WNT2B) were indicated by quantitative real-time polymerase chain reaction (qRT-PCR) in DN tissues and HK2 cells. Meanwhile, the protein level of WNT2B was quantified by Western blot analysis. Besides, the function of cells was examined by Cell Counting Kit-8 (CCK8) assay, flow cytometry assay, western blot, and ELISA kit. Furthermore, the interplay between miR-346 and hsa_circ_0008360 or WNT2B was detected by dual-luciferase reporter assay.

RESULTS

The levels of hsa_circ_0008360 and WNT2B were increased, and the miR-346 level was decreased in the serum of DN patients and HG-treated HK2 cells. For functional analysis, hsa_circ_0008360 deficiency promoted cell viability, inhibits cell apoptosis, inflammatory response, and the synthesis of related fibrotic proteins in HG-treated HK2 cells. Moreover, overexpression of miR-346 induced the proliferation and inhibit apoptosis of HG-induced HK2 cells by inhibiting WNT2B expression. In mechanism, hsa_circ_0008360 acted as a miR-346 sponge to regulate the level of WNT2B.

CONCLUSION

Hsa_circ_0008360 can regulate miR-346/WNT2B axis in HG-induced HK2 cells, providing an underlying targeted therapy for DN patients.

Transcriptomics confirms IRF1 as a key regulator of pyroptosis in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a retinal microvascular complication caused by hyperglycemia, which can lead to visual impairment or blindness. Pyroptosis is a type of inflammation-related programmed cell death, activated by caspase-1, resulting in the maturation of IL-1β and IL-18 and the rupture of the cell membrane. RNA sequencing (RNA-seq) is a high-throughput sequencing technique that reveals the presence and quantity of RNA in the genome at a specific time point, i.e., the transcriptome. RNA-seq can analyze gene expression levels, splicing variants, mutations, fusions, editing and other post-transcriptional modifications, as well as gene expression differences between different samples or conditions. It has been widely used in biological and medical research, clinical diagnosis and new drug development. This study aimed to establish an in vitro model of diabetic retinopathy by culturing human retinal endothelial cells (HREC) with high glucose (30 mmol/L), and to detect their transcriptome expression by RNA-seq, screen for key genes related to pyroptosis, and validate the sequencing results by subsequent experiments.

METHODS

We used RNA-seq to detect the transcriptome expression differences between HREC cells cultured with high glucose and control group, and identified differentially expressed genes by GO/KEGG analysis. We constructed a PPI network and determined the key genes by Cytoscape software and CytoHubba plugin. We validated the expression of related factors by Western Blot, qPCR and ELISA.

RESULTS

We performed GO and KEGG analysis on the RNA-seq data and found differentially expressed genes. We used Cytoscape and CytoHubba plugin to screen out IRF1 as the key gene, and then detected the expression of IRF1 in HREC under high glucose and control group by Western Blot and qPCR. We found that the expression of Caspase-1, GSDMD and IL-1β proteins in HREC under high glucose increased, while the expression of these proteins decreased after the inhibition of IRF1 by siRNA. ELISA showed that the secretion of IL-1β in HREC under high glucose increased, while the inhibition of IRF1 reduced the secretion of IL-1β. These results indicate that IRF1 plays an important role in DR, and provides a new target and strategy for the prevention and treatment of this disease.

Non-coding RNAs in the pathophysiology of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is the largest unmet clinical need in cardiovascular medicine. Despite decades of research, the treatment option for HFpEF is still limited, indicating our ongoing incomplete understanding on the underlying molecular mechanisms. Non-coding RNAs, comprising of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are non-protein coding RNA transcripts, which are implicated in various cardiovascular diseases. However, their role in the pathogenesis of HFpEF is unknown. Here, we discuss the role of miRNAs, lncRNAs and circRNAs that are involved in the pathophysiology of HFpEF, namely microvascular dysfunction, inflammation, diastolic dysfunction and cardiac fibrosis. We interrogated clinical evidence and dissected the molecular mechanisms of the ncRNAs by looking at the relevant in vivo and in vitro models that mimic the co-morbidities in patients with HFpEF. Finally, we discuss the potential of ncRNAs as biomarkers and potential novel therapeutic targets for future HFpEF treatment.

A novel circular RNA, circSQSTM1, protects the endothelial function in atherosclerosis

A novel circRNA named circSQSTM1 (hsa_circRNA_075320) was screened out in atorvastatin (ATV) stimulated endothelial cells (ECs) by our group. Considering the anti-atherosclerotic function of ATV, we hypothesized the circSQSTM1 could protect ECs functions in AS progression. The effects of circSQSTM1 on ECs inflammation, oxidative stress and autophagy were measured by qRT-PCR, Western blotting, monocyte-endothelial adhesion assay, dichloro-dihydro-fluorescein diacetate and mCherry-GFP-LC3 labeling. A luciferase reporter assay, RNA immunoprecipitation, MS2-tagging system and fluorescence in situ hybridization were performed to identify the biological functions of circSQSTM1. The partial left carotid artery ligation model and atherosclerosis model were established to analyze the effects of circSQSTM1 on atherosclerosis progression in vivo. Our results revealed that ATV induced the accumulation of circSQSTM1 in ECs via suppressing m6A modified degradation. In the cytoplasm, circSQSTM1 could relieve Sirt1 by competitively sponging miR-23b-3p. In the nucleus, circSQSTM1 directly interacts with eIF4A3 and promoting the efficient nuclear export of FOXO1 mRNA, which encodes FOXO1 transcription factor to directly activate Sirt1 promoter activity. Hence, circSQSTM1 reduced inflammation, inhibited oxidative stress and promoted autophagy by upregulating Sirt1 in ECs. Moreover, circSQSTM1 overexpression in ECs attenuated the progression of atherosclerosis in ApoE-/- mice. Taken together, the unique noncoding RNA known as circSQSTM1 took a protective role to the ECs in atherosclerosis.

Perspectives of circular RNAs in diabetic complications from biological markers to potential therapeutic targets (Review)

Chronic complications of diabetes increase mortality and disability of patients. It is crucial to find potential early biomarkers and provide novel therapeutic strategies for diabetic complications. Circular RNAs (circRNAs), covalently closed RNA molecules in eukaryotes, have high stability. Recent studies have confirmed that differentially expressed circRNAs have a vital role in diabetic complications. Certain circRNAs, such as circRNA ankyrin repeat domain 36, circRNA homeodomain‑interacting protein kinase 3 (circHIPK3) and circRNA WD repeat domain 77, are associated with inflammation, endothelial cell apoptosis and smooth muscle cell proliferation, leading to vascular endothelial dysfunction and atherosclerosis. CircRNA LDL receptor related protein 6, circRNA actin related protein 2, circ_0000064, circ‑0101383, circ_0123996, hsa_circ_0003928 and circ_0000285 mediate inflammation, apoptosis and autophagy of podocytes, mesangial cell hypertrophy and proliferation, as well as tubulointerstitial fibrosis, in diabetic nephropathy by regulating the expression of microRNAs and proteins. Circ_0005015, circRNA PWWP domain containing 2A, circRNA zinc finger protein 532, circRNA zinc finger protein 609, circRNA DNA methyltransferase 3β, circRNA collagen type I α2 chain and circHIPK3 widely affect multiple biological processes of diabetic retinopathy. Furthermore, circ_000203, circ_010567, circHIPK3, hsa_circ_0076631 and circRNA cerebellar degeneration‑related protein 1 antisense are involved in the pathology of diabetic cardiomyopathy. CircHIPK3 is the most well‑studied circRNA in the field of diabetic complications and is most likely to become a biological marker and therapeutic target for diabetic complications. The applications of circRNAs may be a promising treatment strategy for human diseases at the molecular level. The relationship between circRNAs and diabetic complications is summarized in the present study. Of note, circRNA‑targeted therapy and the role of circRNAs as biomarkers may potentially be used in diabetic complications in the future.

Interaction between the expression of hsa_circRPRD1A and hsa_circHERPUD2 and classical coronary risk factors promotes the development of coronary artery disease

BACKGROUND

Recent studies suggest that classical coronary risk factors play a significant role in the pathogenesis of coronary artery disease. Our study aims to explore the interaction of circRNA with classical coronary risk factors in coronary atherosclerotic disease.

METHOD

Combined analysis of RNA sequencing results from coronary segments and peripheral blood mononuclear cells of patients with coronary atherosclerotic disease was employed to identify critical circRNAs. Competing endogenous RNA networks were constructed by miRanda-3.3a and TargetScan7.0. The relative expression quantity of circRNA in peripheral blood mononuclear cells was determined by qRT-PCR in a large cohort including 256 patients and 49 controls. Spearman's correlation test, receiver operating characteristic curve analysis, multivariable logistic regression analysis, one-way analysis of variance, and crossover analysis were performed.

RESULTS

A total of 34 circRNAs were entered into our study, hsa_circRPRD1A, hsa_circHERPUD2, hsa_circLMBR1, and hsa_circDHTKD1 were selected for further investigation. A circRNA-miRNA-mRNA network is composed of 20 microRNAs and 66 mRNAs. The expression of hsa_circRPRD1A (P = 0.004) and hsa_circHERPUD2 (P = 0.003) were significantly down-regulated in patients with coronary artery disease compared to controls. The area under the curve of hsa_circRPRD1A and hsa_circHERPUD2 is 0.689 and 0.662, respectively. Univariate and multivariable logistic regression analyses identified hsa_circRPRD1A (OR = 0.613, 95%CI:0.380-0.987, P = 0.044) as a protective factor for coronary artery disease. Based on the additive model, crossover analysis demonstrated that there was an antagonistic interaction between the expression of hsa_circHERPUD2 and alcohol consumption in subjects with coronary artery disease.

CONCLUSION

Our findings imply that hsa_circRPRD1A and hsa_circHERPUD2 could be used as biomarkers for the diagnosis of coronary artery disease and provide epidemiological support for the interactions between circRNAs and classical coronary risk factors.

Key circRNAs, lncRNAs, and mRNAs of ShenQi Compound in Protecting Vascular Endothelial Cells From High Glucose Identified by Whole Transcriptome Sequencing

ABSTRACT

Vascular endothelial cells, which make up the inner wall of blood arteries, are susceptible to damage from oxidative stress and apoptosis caused by hyperglycemia. According to certain reports, noncoding RNAs are involved in controlling oxidative stress and apoptosis. ShenQi Compound (SQC), a traditional herbal remedy, has been successfully treating diabetic vascular disease in China for more than 20 years. Although it is well established that SQC protects the vascular endothelium, the molecular mechanism remains unknown. Goto-Kakizaki rats, spontaneous type II diabetes rats, that consistently consume a high-fat diet were chosen as model animals. Six groups (control group, model group, metformin group, and 7.2 g/kg/d SQC group, 14.4 g/kg/d SQC group, and 28.8 g/kg/d SQC group) were included in this work, 15 rats each group. The approach of administration was gavage, and the same volume (5.0 mL/kg/d) was given in each group, once a day, 12 weeks. The thoracic aortas were removed after the rats were sacrificed. Oxidative reduction profile in thoracic aorta, histopathological observation of thoracic aorta, endothelial cell apoptosis in thoracic aorta, whole transcriptome sequencing, bioinformatic analyses, and qRT-PCR were conducted. As a result, SQC prevented the oxidative stress and apoptosis induced by a high glucose concentration. Under hyperglycemia condition, noncoding RNAs, including 1 downregulated novel circRNA (circRNA.3121), 3 downregulated lncRNAs (Skil.cSep08, Shawso.aSep08-unspliced, and MSTRG.164.2), and 1 upregulated mRNA (Pcdh17), were clearly reverse regulated by SQC. SQC plays a role in protecting vascular endothelial cells from high glucose mainly by mediating ncRNA to inhibit cell apoptosis and oxidative stress.

[Research advances on the mechanism of non-coding RNA regulated diabetic wound healing]

Diabetic wounds are a common complication of diabetic patients, and the incidence has been increasing in recent years. In addition, its poor clinical prognosis seriously affects the quality of life of patients, which has become the focus and difficulty of diabetes treatment. As the RNA regulating gene expression, non-coding RNA can regulate the pathophysiological process of diseases, and play an important role in the healing process of diabetic wounds. In this paper, we reviewed the regulatory role, diagnostic value, and therapeutic potential of three common non-coding RNA in diabetic wounds, in order to provide a new solution for the diagnosis and treatment of diabetic wounds at the genetic and molecular level.

Involvement of circRNAs in the Development of Heart Failure

In recent years, interest in non-coding RNAs as important physiological regulators has grown significantly. Their participation in the pathophysiology of cardiovascular diseases is extremely important. Circular RNA (circRNA) has been shown to be important in the development of heart failure. CircRNA is a closed circular structure of non-coding RNA fragments. They are formed in the nucleus, from where they are transported to the cytoplasm in a still unclear mechanism. They are mainly located in the cytoplasm or contained in exosomes. CircRNA expression varies according to the type of tissue. In the brain, almost 12% of genes produce circRNA, while in the heart it is only 9%. Recent studies indicate a key role of circRNA in cardiomyocyte hypertrophy, fibrosis, autophagy and apoptosis. CircRNAs act mainly by interacting with miRNAs through a "sponge effect" mechanism. The involvement of circRNA in the development of heart failure leads to the suggestion that they may be promising biomarkers and useful targets in the treatment of cardiovascular diseases. In this review, we will provide a brief introduction to circRNA and up-to-date understanding of their role in the mechanisms leading to the development of heart failure.

The mechanisms of glycolipid metabolism disorder on vascular injury in type 2 diabetes

Patients with diabetes have severe vascular complications, such as diabetic nephropathy, diabetic retinopathy, cardiovascular disease, and neuropathy. Devastating vascular complications lead to increased mortality, blindness, kidney failure, and decreased overall quality of life in people with type 2 diabetes (T2D). Glycolipid metabolism disorder plays a vital role in the vascular complications of T2D. However, the specific mechanism of action remains to be elucidated. In T2D patients, vascular damage begins to develop before insulin resistance and clinical diagnosis. Endothelial dysregulation is a significant cause of vascular complications and the early event of vascular injury. Hyperglycemia and hyperlipidemia can trigger inflammation and oxidative stress, which impair endothelial function. Furthermore, during the pathogenesis of T2D, epigenetic modifications are aberrant and activate various biological processes, resulting in endothelial dysregulation. In the present review, we provide an overview and discussion of the roles of hyperglycemia- and hyperlipidemia-induced endothelial dysfunction, inflammatory response, oxidative stress, and epigenetic modification in the pathogenesis of T2D. Understanding the connections of glucotoxicity and lipotoxicity with vascular injury may reveal a novel potential therapeutic target for diabetic vascular complications.

CircRNA-miRNA interactions in atherogenesis

Atherosclerosis is the major cause of coronary artery disease (CAD) which includes unstable angina, myocardial infarction, and heart failure. The onset of atherogenesis, a process of atherosclerotic lesion formation in the intima of arteries, is driven by lipid accumulation, a vicious cycle of reactive oxygen species (ROS)-induced oxidative stress and inflammatory reactions leading to endothelial cell (EC) dysfunction, vascular smooth muscle cell (VSMC) activation, and foam cell formation which further fuel plaque formation and destabilization. In recent years, there is a surge in the number of publications reporting the involvement of circular RNAs (circRNAs) in the pathogenesis of cardiovascular diseases, cancers, and metabolic syndromes. These studies have advanced our understanding on the biological functions of circRNAs. One of the most common mechanism of action of circRNAs reported is the sponging of microRNAs (miRNAs) by binding to the miRNAs response element (MRE), thereby indirectly increases the transcription of their target messenger RNAs (mRNAs). Individual networks of circRNA-miRNA-mRNA associated with atherogenesis have been extensively reported, however, there is a need to connect these findings for a complete overview. This review aims to provide an update on atherogenesis-related circRNAs and analyze the circRNA-miRNA-mRNA interactions in atherogenesis. The atherogenic mechanisms and clinical relevance of each atherogenesis-related circRNA were systematically discussed for better understanding of the knowledge gap in this area.

Knockdown of circ_0003928 ameliorates high glucose-induced dysfunction of human tubular epithelial cells through the miR-506-3p/HDAC4 pathway in diabetic nephropathy

Background

Previous data have indicated the importance of circular RNA (circRNA) in the pathogenesis of diabetic nephropathy (DN). The study is designed to investigate the effects of circ_0003928 on oxidative stress and apoptosis of high glucose (HG)-treated human tubular epithelial cells (HK-2) and the underlying mechanism.

Methods

The DN cell model was established by inducing HK-2 cells using 30 mmol/L D-glucose. RNA expression of circ_0003928, miR-506-3p and histone deacetylase 4 (HDAC4) was detected by quantitative real-time polymerase chain reaction. Cell viability and proliferation were investigated by cell counting kit-8 and 5-Ethynyl-29-deoxyuridine (EdU) assays, respectively. Oxidative stress was evaluated by commercial kits. Caspase 3 activity and cell apoptotic rate were assessed by a caspase 3 activity assay and flow cytometry analysis, respectively. Protein expression was detected by Western blotting analysis. The interactions among circ_0003928, miR-506-3p and HDAC4 were identified by dual-luciferase reporter and RNA pull-down assays.

Results

Circ_0003928 and HDAC4 expression were significantly upregulated, while miR-506-3p was downregulated in the serum of DN patients and HG-induced HK-2 cells. HG treatment inhibited HK-2 cell proliferation, but induced oxidative stress and cell apoptosis; however, these effects were reversed after circ_0003928 depletion. Circ_0003928 acted as a miR-506-3p sponge, and HDAC4 was identified as a target gene of miR-506-3p. Moreover, the circ_0003928/miR-506-3p/HDAC4 axis regulated HG-induced HK-2 cell dysfunction.

Conclusion

Circ_0003928 acted as a sponge for miR-506-3p to regulate HG-induced oxidative stress and apoptosis of HK-2 cells through HDAC4, which suggested that circ_0003928 might be helpful in the therapy of DN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00679-y.

The role of circRNAs in the regulation of myocardial angiogenesis in coronary heart disease

During myocardial ischemia, timely reperfusion is critical to limit infarct area and the overall loss of cardiac contractile function. New treatment strategies need to be developed for patients who are neither able to receive interventional treatment nor suitable for surgical blood transport reconstruction surgery. Therapeutic angiogenesis is a promising approach that can be used to guide new treatment strategies. The goal of these therapies is to form new blood vessels or promote the maturation of existing vasculature systems, bypassing blocked arteries to maintain organ perfusion, thereby relieving symptoms and preventing the remodeling of bad organs. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), have been attracted much attention for their roles in various physiological and pathological processes. There is growing evidence that ncRNAs, especially circRNAs, play an important role in the regulation of cardiomyopathy angiogenesis due to its diversity of functions. Therefore, this article reviews the role and mechanisms of circRNA in myocardial angiogenesis to better understand the role of circRNAs in myocardial angiogenesis, which may provide useful insights and new revelations for the research field of identifying diagnostic markers and therapeutic approaches for the treatment of coronary artery disease.

Deciphering the link between Diabetes mellitus and SARS-CoV-2 infection through differential targeting of microRNAs in the human pancreas

PURPOSE

Coronavirus Disease 2019 (COVID-19) severity and Diabetes mellitus affect each other bidirectionally. However, the cause of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection on the incidence of diabetes is unclear. In the SARS-CoV-2-infected cells, host microRNAs (miRNAs) may target the native gene transcripts as well as the viral genomic and subgenomic RNAs. Here, we investigated the role of miRNAs in linking Diabetes to SARS-CoV-2 infection in the human pancreas.

METHODS

Differential gene expression and disease enrichment analyses were performed on an RNA-Seq dataset of human embryonic stem cell-derived (hESC) mock-infected and SARS-CoV-2-infected pancreatic organoids to obtain the dysregulated Diabetes-associated genes. The miRNA target prediction for the Diabetes-associated gene transcripts and the SARS-CoV-2 RNAs has been made to determine the common miRNAs targeting them. Minimum Free Energy (MFE) analysis was done to identify the miRNAs, preferably targeting SARS-CoV-2 RNAs over the Diabetes-associated gene transcripts.

RESULTS

The gene expression and disease enrichment analyses of the RNA-Seq data have revealed five biomarker genes, i.e., CP, SOCS3, AGT, PSMB8 and CFB that are associated with Diabetes and get significantly upregulated in the pancreas following SARS-CoV-2-infection. Four miRNAs, i.e., hsa-miR-298, hsa-miR-3925-5p, hsa-miR-4691-3p and hsa-miR-5196-5p, showed preferential targeting of the SARS-CoV-2 genome over the cell's Diabetes-associated messenger RNAs (mRNAs) in the human pancreas.

CONCLUSION

Our study proposes that the differential targeting of the Diabetes-associated host genes by the miRNAs may lead to diabetic complications or new-onset Diabetes that can worsen the condition of COVID-19 patients.

Exosomal circTAOK1 contributes to diabetic kidney disease progression through regulating SMAD3 expression by sponging miR-520h

BACKGROUND

Diabetic nephropathy (DN) is a frequent diabetes complication with complex pathogenesis. Circular RNA (circRNA) circTAOK1 (also named circ_0003928) has been reported to be upregulated in high glucose (HG)-treated human umbilical vein endothelial cells. Also, exosomal circRNAs can exert significant roles in the pathology of various diseases. This study is designed to explore the role and mechanism of exosomal circTAOK1 on the glomerular mesangial cell (GMC) injury in DN.

METHODS

Exosomes were detected by a transmission electron microscope. The protein levels of CD9, CD63, proliferating cell nuclear antigen (PCNA), cyclinD1, α-SMA, fibronectin, E-cadherin, N-cadherin, and SMAD family member 3 (SMAD3) were examined by western blot assay. circTAOK1, microRNA-520h (miR-520h), and SMAD3 levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation and cell cycle progression were detected by cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays. The binding relationship between miR-520h and circTAOK1 or SMAD3 was predicted by Starbase and then verified by a dual-luciferase reporter and RNA immunoprecipitation (RIP), RNA pull-down assays.

RESULTS

CircTAOK1 expression was upregulated in the exosomes isolated from HG-treated glomerular epithelial cells (GEC). Moreover, GEC-circTAOK1-Exo could promote proliferation, fibrosis, and epithelial-mesenchymal transition (EMT) of glomerular mesangial cells (GMCs). Mechanically, circTAOK1 could regulate SMAD3 expression by sponging miR-520h, GEO-si-circTAOK1 Exo-induced miR-520h and repressed SMAD3 expression in GMC.

CONCLUSION

GEC-circTAOK1-Exo could boost proliferation, fibrosis, and EMT of GMC through targeting the miR-520h/SMAD3 axis, providing new insights into the pathogenesis of DN.

Hsa_circ_0008360 sponges miR-186-5p to target CCND2 to modulate high glucose-induced vascular endothelial dysfunction

Vascular endothelial dysfunction is associated with the progress of many diseases. Circular RNAs (circRNAs) take part in the dysfunction of vascular endothelium. CircRNA hsa_circ_0008360 (circ_0008360) is dysregulated in high glucose-treated vascular endothelium, while the role and mechanism of circ_0008360 in high glucose-induced dysfunction remain unknown. Human umbilical vascular endothelium cells (HUVEC) were stimulated via high glucose. The abundances of circ_0008360, miR-186-5p and cyclin D2 (CCND2) were examined via quantitative real-time polymerase chain reaction or western blot. Vascular endothelial dysfunction was assessed via cell viability, apoptosis, migration and tube formation. The target relationship between miR-186-5p and circ_0008360 or CCND2 was analyzed via dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation analyses. Circ_0008360 expression was enhanced in high-glucose-treated HUVEC. Circ_0008360 silence mitigated high glucose-induced suppression of viability, migration, tube formation, and increase in apoptosis in HUVEC. MiR-186-5p was sponged by circ_0008360, and miR-186-5p inhibition reversed the effect of circ_0008360 silence on high glucose-induced vascular endothelial dysfunction. MiR-186-5p alleviated high glucose-induced vascular endothelial dysfunction via targeting CCND2. CCND2 interference abolished the aggravated effect of circ_0008360 on high glucose-induced vascular endothelial dysfunction. Circ_0008360 knockdown attenuated high glucose-induced vascular endothelial dysfunction via regulating miR-186-5p and CCND2, indicating circ_0008360 might act as a target for the treatment of vascular endothelial dysfunction.Abbreviations: circRNAs, circular RNAs; HUVEC, human umbilical vascular endothelium cells; CCND2, cyclin D2; XPNPEP3, X-prolyl aminopeptidase 3; ceRNAs, competing endogenous RNAs; miRNAs, microRNAs; qRT-PCR, quantitative real-time polymerase chain reaction; RIP, RNA immunoprecipitation; HIF-1α, hypoxia inducible factor 1 alpha; TLR3, toll-like receptor 3; AKAP12, A-Kinase Anchoring Protein 12; ox-LDL, oxidized low-density lipoprotein; HG, high glucose; NG, normal glucose.

The progress, prospects, and challenges of the use of non-coding RNA for diabetic wounds

Chronic diabetic wounds affect the quality of life of patients, resulting in significant social and economic burdens on both individuals and the health care system. Although treatment methods for chronic diabetic wounds have been explored, there remains a lack of effective treatment strategies; therefore, alternative strategies must be explored. Recently, the abnormal expression of non-coding RNA in diabetic wounds has received widespread attention since it is an important factor in the development of diabetic wounds. This article reviews the regulatory role of three common non-coding RNAs (microRNA [miRNA], long non-coding RNA [lncRNA], and circular RNA [circRNA]) in diabetic wounds and discusses the diagnosis, treatment potential, and challenges of non-coding RNA in diabetic wounds. This article provides insights into new strategies for diabetic wound diagnosis and treatment at the genetic and molecular levels.

Circ_CLASP2 Regulates High Glucose-Induced Dysfunction of Human Endothelial Cells Through Targeting miR-140-5p/FBXW7 Axis

Hyperglycemia exposure results in the dysfunction of endothelial cells (ECs) and the development of diabetic complications. Circular RNAs (circRNAs) have been demonstrated to play critical roles in EC dysfunction. The current study aimed to explore the role and mechanism of circRNA CLIP–associating protein 2 (circ_CLASP2, hsa_circ_0064772) on HG-induced dysfunction in human umbilical vein endothelial cells (HUVECs). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assess the levels of circ_CLASP2, miR-140-5p and F-box, and WD repeat domain-containing 7 (FBXW7). The stability of circ_CLASP2 was identified by the actinomycin D and ribonuclease (RNase) R assays. Cell colony formation, proliferation, and apoptosis were measured by a standard colony formation assay, colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay, and flow cytometry, respectively. Western blot analysis was performed to determine the expression of related proteins. Targeted correlations among circ_CLASP2, miR-140-5p, and FBXW7 were confirmed by dual-luciferase reporter assay. High glucose (HG) exposure downregulated the expression of circ_CLASP2 in HUVECs. Circ_CLASP2 overexpression or miR-140-5p knockdown promoted proliferation and inhibited apoptosis of HUVECs under HG conditions. Circ_CLASP2 directly interacted with miR-140-5p via pairing to miR-140-5p. The regulation of circ_CLASP2 overexpression on HG-induced HUVEC dysfunction was mediated by miR-140-5p. Moreover, FBXW7 was a direct target of miR-140-5p, and miR-140-5p regulated HG-induced HUVEC dysfunction via FBXW7. Furthermore, circ_CLASP2 mediated FBXW7 expression through sponging miR-140-5p. Our current study suggested that the overexpression of circ_CLASP2 protected HUVEC from HG-induced dysfunction at least partly through the regulation of the miR-140-5p/FBXW7 axis, highlighting a novel therapeutic approach for the treatment of diabetic-associated vascular injury.

CircRNAs in diabetic cardiomyopathy

Diabetic cardiomyopathy is an important irreversible chronic cardiovascular complication in diabetic patients. This condition is described as early diastolic dysfunction, myocardial fibrosis, cardiac hypertrophy, systolic dysfunction and other complex pathophysiological events, which ultimately lead to heart failure. Despite these characteristics, the underlying mechanisms resulting in diabetic cardiomyopathy are still unknown. With the developments in molecular biotechnology, increasing evidence shows that circRNAs play critical roles in the pathogenesis of diabetic cardiomyopathy. The purpose of this review is to summarize recent studies on the role of circRNAs in the pathophysiological process to provide novel prevention and treatment strategies for diabetic cardiomyopathy, oxidative stress, inflammation, endothelial dysfunction, myocardial fibrosis and cell death in diabetic cardiomyopathy.

Implication of regulatory networks of long noncoding RNA/circular RNA-miRNA-mRNA in diabetic cardiovascular diseases

Diabetic cardiovascular diseases (DCVDs) are the most common complications of diabetes mellitus and are considered to be one of the most important threats to global health and an economic burden. Long noncoding RNA (lncRNA), circular RNA (circRNA), and miRNA are a novel group of noncoding RNAs that are involved in the regulation of various pathophysiological processes, including DCVDs. Interestingly, both lncRNA and circRNA can act as competing endogenous RNA of miRNA, thereby regulating the expression of the target mRNA by decoying or sponging the miRNA. In this review, we focus on the mechanistic, pathological and functional roles of lncRNA/circRNA-miRNA-mRNA networks in DCVDs and further discuss the potential implications for early detection, therapeutic intervention and prognostic evaluation.

Circular RNAs: Potential Star Molecules Involved in Diabetic Retinopathy

Purpose: To summarize the research status on the function and mechanism of circRNAs in regulating the occurrence of diabetic retinopathy (DR). Methods: We systematically searched PubMed, Embase.com, and ARVO Abstracts website and reviewed relevant studies. Results: Thousands of circRNAs were found to be aberrantly expressed in DR patients, animal models, or cell models. A few circRNAs, such as cPWWP2A, circDNMT3B, circHIPK3, circ_0005015, et al were demonstrated to play an important role in DR by regulating the angiogenesis, proliferation, apoptosis, and inflammatory response of various cells in the retina. Conclusion: CircRNAs are involved in the development of DR. CircRNAs can not only serve as DR biomarkers, but also become therapeutic targets for DR. The role of plenty of circRNAs in DR is yet to be discovered.

Roles of circular RNAs in diabetic complications: From molecular mechanisms to therapeutic potential

Diabetes is characterized by changed homeostasis of blood glucose levels, which is associated with various complications, including cardiomyopathy, atherosclerosis, endothelial dysfunction, nephropathy, retinopathy and neuropathy. In recent years, accumulative evidence has demonstrated that circular RNAs are identified as a novel type of noncoding RNAs (ncRNAs) involving in the regulation of various physiological processes and pathologic conditions. Specifically, the emergence of complications response to diabetes is finely controlled by a complex gene regulatory network in which circular RNAs play a critical role. Recently, circular RNAs are emerging as messengers that could influence cellular functions under diabetic conditions. Dysregulation of circular RNAs has been closely linked to the pathophysiology of diabetes-related complications. In this review, we aimed to summarize the current progression and underlying mechanisms of circular RNA in the development of diabetes-related complications. We will also provide an overview of circular RNA-regulated cell communications in different types of cells that have been linked to diabetic complications. We anticipated that the completion of this review will provide potential clues for developing novel circular RNAs-based biomarkers or therapeutic targets for diabetes and its associated complications.

CircBPTF knockdown ameliorates high glucose-induced inflammatory injuries and oxidative stress by targeting the miR-384/LIN28B axis in human umbilical vein endothelial cells

Endothelial dysfunction is a primary cause of diabetes-related vascular complications, such as atherosclerosis. Accumulated research indicates that circular RNAs (circRNAs) are involved in the pathogenesis of cardiovascular disease. This study intended to explore the function and mechanism of circBPTF in high glucose (HG)-induced vascular inflammatory models. Cell model of inflammatory injury was established in human umbilical vein endothelial cells (HUVECs) with HG treatment. The expression of circBPTF, miR-384 and lin-28 homolog B (LIN28B) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were assessed by cell counting kit-8 (CCK-8) and flow cytometry assay, respectively. The expression of LIN28B was also examined using western blot. The release of proinflammatory cytokines was detected by enzyme-linked immunosorbent assay (ELISA). The production of ROS, SOD and MDA was detected to assess oxidative stress. The target relationship was predicted by bioinformatics analysis and verified using dual-luciferase reporter assay and RIP assay. CircBPTF was highly regulated in HG-induced HUVECs. CircBPTF knockdown increased cell viability and suppressed cell apoptosis, the release of proinflammatory cytokines and oxidative stress in HG-induced HUVECs. MiR-384 was targeted by circBPTF, and its downregulation abolished the effects of circBPTF knockdown. Moreover, circBPTF positively regulated LIN28B expression via targeting miR-384. Overall, CircBPTF knockdown protected against HG-induced inflammatory injuries and oxidative stress by mediating the miR-384/LIN28B axis in HUVECs. Our study provides a feasible theoretical strategy for preventing vascular cell dysfunction.

Circular RNAs in the pathogenesis of atherosclerosis

Atherosclerosis is a common cause of cardiovascular and cerebrovascular diseases. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) have attracted substantial attention for their roles in various physiological and pathological processes. In recent years, research on the roles of circRNAs in atherosclerosis has progressed rapidly, and they have been implicated in the pathophysiological processes underlying the development of atherosclerosis, including changes in the functions of endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and macrophages. In this review article, we summarize currently available data regarding the role of circRNAs in atherosclerosis and how circRNAs influence the development of atherosclerosis by regulating ECs, VSMCs, and macrophages. We also discuss their potential as diagnostic biomarkers for coronary artery disease.

Dexmedetomidine alleviates postoperative cognitive dysfunction through circular RNA in aged rats

Circular RNA (circRNA) has been well studied in many diseases, whereas their role in patients with postoperative cognitive dysfunction (POCD) remains largely unclear. Here, we investigated the therapeutic effects of dexmedetomidine (Dex) on POCD and analyzed the role of circRNA as well as the pathways that may be involved. The Morris water maze test demonstrated that POCD rats have a longer incubation period than the normal group, but the latency of POCD rats was significantly lower after Dex treatment. Moreover, HE staining showed that Dex improved hippocampal pathological changes. RNA sequencing showed 164 differentially expressed circRNAs between POCD and Dex groups; 74 were upregulated and 90 were downregulated in the Dex group. A total of 20,790 target genes for differentially expressed circRNAs were observed in RNAhybrid and Miranda databases. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that the target genes of differentially expressed circRNAs are mainly focused on positive regulation of intrinsic apoptotic signaling pathway in response to DNA damage, negative regulation of cell adhesion mediated by integrin, and response to cytokines and other function of life activities and involved in the P53 signaling pathway and nuclear factor kappa B (NF-κB) signaling pathway. Furthermore, the expression of five candidate circRNAs (circ-Shank3, circ-Cdc42bpa, circ-chrx-24658, cir-chr17-3642 and circ-Sgsm1) and target genes were consistent with the RNA sequencing results, which was verified by quantitative real-time polymerase chain reaction (qRT-PCR). These results indicate that circ-Shank3 participate in the process of Dex improved POCD through regulating the P53 and NF-κB signaling pathways and may potentially facilitate POCD treatment through the development of clinical drugs.

Interference of Hsa_circ_0003928 Alleviates High Glucose-Induced Cell Apoptosis and Inflammation in HK-2 Cells via miR-151-3p/Anxa2

BACKGROUND

Diabetic nephropathy (DN) is a severe end-stage kidney disease developed from diabetes mellitus. The involvement of circular RNA (circRNAs) in the regulation of DN pathogenesis has been implied, but the underlying mechanism of DN is still lacking. This study aimed to investigate the effect of hsa_circ_0003928 on the inflammation and apoptosis of high glucose (HG)-induced renal tubular cells.

METHODS

The expression of hsa_circ_0003928, miR-151-3p and Anxa2 in blood samples from DN patients and healthy controls was detected by RT-qPCR. Human renal epithelial cells HK-2 were incubated with D-glucose (30 mmol/l) to establish DN model in vitro. RT-qPCR analysis confirmed the transfection effects and detected the expressions of TNF-α, IL-6 and IL-1β. Western blotting analysis determined the protein expression of Anxa2, Bcl-2, Bax, cleaved caspase-3 and caspase-3. The production of ROS was detected by DCF-DA method and production of inflammatory cytokines was verified by ELISA assay. CCK-8 assay and TUNEL assay were performed to determine cell viability and apoptosis, respectively. Dual-luciferase reporter assay was performed to confirm the relationship between miR-151-3p and hsa_circ_0003928 or Anxa2.

RESULTS

Hsa_circ_0003928 and Anxa2 mRNA levels were increased, whereas miR-151-3p was decreased in both HG-induced HK-2 cells and patients with DN. Hsa_circ_0003928 knockdown could decrease cell viability loss and apoptosis, increase Bcl-2 expression, and decrease Bax and cleaved caspase-3 expression. Besides, hsa_circ_0003928 knockdown suppressed HG-induced overproduction of ROS, TNF-α, IL-6 and IL-1β. However, the effects made by miR-151-3p inhibition were opposite to those made by hsa_circ_0003928 knockdown. Furthermore, the binding sites between miR-151-3p and hsa_circ_0003928 or Anxa2 were predicted and verified. Protein expression of Anxa2 was suppressed by hsa_circ_0003928 knockdown, which was rescued by miR-151-3p inhibition.

CONCLUSION

These results demonstrated that hsa_circ_0003928 could act as a sponge of miR-151-3p and regulate HG-induced inflammation and apoptosis partly through regulating Anxa2.