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

Circ_0005699 Expedites ox-LDL-Triggered Endothelial Cell Injury via Targeting miR-384/ASPH Axis

Atherosclerosis (AS) is an inflammatory disease with multiple causes. Multiple circular RNAs (circRNAs) are known to be involved in the pathogenesis of AS. To explore the function and mechanism of circ_0005699 in oxidative low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs) injury. Ox-LDL treatment restrained HUVECs viability, cell proliferation, and angiogenesis ability, and accelerated HUVECs apoptosis, inflammatory response, and oxidative stress. Circ_0005699 was up-regulated in the serum samples of AS patients and ox-LDL-induced HUVECs. Interference of circ_0005699 effectively rescued ox-LDL-induced injury in HUVECs. Additionally, miR-384 could bind to circ_0005699, and miR-384 depletion inverted the effects of circ_0005699 deficiency on ox-LDL-mediated HUVEC injury. Moreover, ASPH was a direct target of miR-384, and the enforced expression of ASPH overturned miR-384-induced effects on ox-LDL-induced HUVECs. Importantly, circ_0005699 regulated ASPH expression via sponging miR-384. Interference of circ_0005699 protected against ox-LDL-induced injury in HUVECs at least partly by regulating ASPH expression via acting as a miR-384 sponge.

Epigenetic modification: A novel insight into diabetic wound healing

Wound healing is an intricate and fine regulatory process. In diabetic patients, advanced glycation end products (AGEs), excessive reactive oxygen species (ROS), biofilm formation, persistent inflammation, and angiogenesis regression contribute to delayed wound healing. Epigenetics, the fast-moving science in the 21st century, has been up to date and associated with diabetic wound repair. In this review, we go over the functions of epigenetics in diabetic wound repair in retrospect, covering transcriptional and posttranscriptional regulation. Among these, we found that histone modification is widely involved in inflammation and angiogenesis by affecting macrophages and endothelial cells. DNA methylation is involved in factors regulation in wound repair but also affects the differentiation phenotype of cells in hyperglycemia. In addition, noncodingRNA regulation and RNA modification in diabetic wound repair were also generalized. The future prospects for epigenetic applications are discussed in the end. In conclusion, the study suggests that epigenetics is an integral regulatory mechanism in diabetic wound healing.

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.

LncRNA/CircRNA-miRNA-mRNA Axis in Atherosclerotic Inflammation: Research Progress

Atherosclerosis is characterized by chronic inflammation of the arterial wall. However, the exact mechanism underlying atherosclerosis-related inflammation has not been fully elucidated. To gain insight into the mechanisms underlying the inflammatory process that leads to atherosclerosis, there is need to identify novel molecular markers. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-protein-coding RNAs (lncRNAs) and circular RNAs (circRNAs) have gained prominence in recent years. LncRNAs/circRNAs act as competing endogenous RNAs (ceRNAs) that bind to miRNAs via microRNA response elements (MREs), thereby inhibiting the silencing of miRNA target mRNAs. Inflammatory mediators and inflammatory signaling pathways are closely regulated by ceRNA regulatory networks in atherosclerosis. In this review, we discuss the role of LncRNA/CircRNA-miRNA-mRNA axis in atherosclerotic inflammation and how it can be targeted for early clinical detection and treatment.

Decrypting the circular RNAs does a favor for us: Understanding, diagnosing and treating diabetes mellitus and its complications

Circular RNAs (circRNAs), a novel type of single-stranded noncoding RNAs with a covalently closed loop structure, are generated in a circular conformation via non-canonical splicing or back-splicing events. Functionally, circRNAs have been elucidated to soak up microRNAs (miRNAs) and RNA binding proteins (RBPs), serve as protein scaffolds, maintain mRNA stability, and regulate gene transcription and translation. Notably, circRNAs are strongly implicated in the regulation of β-cell functions, insulin resistance, adipocyte functions, inflammation as well as oxidative stress via acting as miRNA sponges and RBP sponges. Basic and clinical studies have demonstrated that aberrant alterations of circRNAs expressions are strongly associated with the initiation and progression of diabetes mellitus (DM) and its complications. Here in this review, we present a summary of the biogenesis, transportation, degradation and functions of circRNAs, and highlight the recent findings on circRNAs and their action mechanisms in DM and its complications. Overall, this review should contribute greatly to our understanding of circRNAs in DM pathogenesis, offering insights into the further perspectives of circRNAs for DM diagnosis and therapy.

circRNA-miRNA-mRNA Deregulated Network in Ischemic Heart Failure Patients

Noncoding RNAs (ncRNAs), which include circular RNAs (circRNAs) and microRNAs (miRNAs), regulate the development of cardiovascular diseases (CVD). Notably, circRNAs can interact with miRNAs, influencing their specific mRNA targets' levels and shaping a competing endogenous RNAs (ceRNA) network. However, these interactions and their respective functions remain largely unexplored in ischemic heart failure (IHF). This study is aimed at identifying circRNA-centered ceRNA networks in non-end-stage IHF. Approximately 662 circRNA-miRNA-mRNA interactions were identified in the heart by combining state-of-the-art bioinformatics tools with experimental data. Importantly, KEGG terms of the enriched mRNA indicated CVD-related signaling pathways. A specific network centered on circBPTF was validated experimentally. The levels of let-7a-5p, miR-18a-3p, miR-146b-5p, and miR-196b-5p were enriched in circBPTF pull-down experiments, and circBPTF silencing inhibited the expression of HDAC9 and LRRC17, which are targets of miR-196b-5p. Furthermore, as suggested by the enriched pathway terms of the circBPTF ceRNA network, circBPTF inhibition elicited endothelial cell cycle arrest. circBPTF expression increased in endothelial cells exposed to hypoxia, and its upregulation was confirmed in cardiac samples of 36 end-stage IHF patients compared to healthy controls. In conclusion, circRNAs act as miRNA sponges, regulating the functions of multiple mRNA targets, thus providing a novel vision of HF pathogenesis and laying the theoretical foundation for further experimental studies.

Metformin regulates the LIN28B‑mediated JNK/STAT3 signaling pathway through miR‑140‑3p in subretinal fibrosis

Subretinal fibrosis (SF) is an important cause of submacular neovascularization that leads to permanent vision loss, but has no effective clinical treatment. The present study examined the influence of metformin on SF, and investigated whether the mechanism involves the microRNA (miR)-140-3p/LIN28B/JNK/STAT3-mediated regulation of oxidative stress, angiogenesis and fibrosis-associated indicators. A mouse model of laser-induced SF was established. In addition, an ARPE-19 fibrotic cell model was established using TGF-β1. A Cell Counting Kit-8 assay was used to examine cell viability. Flow cytometry was used to measure reactive oxygen species levels, and western blotting was used to detect the levels of proteins associated with epithelial-mesenchymal transition (EMT), signaling and fibrosis. The levels of superoxide dismutase, malondialdehyde, glutathione-peroxidase and catalase were measured using kits. Scratch assays and Transwell assays were used to assess cell migration and invasion, respectively, and reverse transcription-quantitative PCR was used to determine the levels of miR-140-3p and LIN28B. Dual-luciferase assays were used to verify the targeting relationship between miR-140-3p and LIN28B, and coimmunoprecipitation was used to confirm the interaction between LIN28B and JNK. Masson staining and hematoxylin and eosin staining were used to examine collagenous fibers and the histopathology of eye tissue. In ARPE-19 cells induced by TGF-β1, metformin promoted miR-140-3p expression and inhibited LIN28B expression and JNK/STAT3 pathway activation, thereby inhibiting oxidative stress, EMT and fibrosis in ARPE-19 cells. The overexpression of LIN28B or treatment with the JNK/STAT3 agonist anisomycin partially reversed the inhibitory effect of metformin on oxidative stress and fibrosis in ARPE-19 cells. The dual-luciferase reporter assay and coimmunoprecipitation assay showed that miR-140-3p targeted the 3' untranslated region of LIN28B mRNA and inhibited LIN28B expression. LIN28B targeted and bound to JNK and regulated the JNK/STAT3 pathway. Therefore, it may be concluded that metformin can promote miR-140-3p expression, inhibit LIN28B and then inhibit the JNK/STAT3 pathway to alleviate SF.

Circular RNA as Therapeutic Targets in Atherosclerosis: Are We Running in Circles?

Much attention has been paid lately to harnessing the diagnostic and therapeutic potential of non-coding circular ribonucleic acids (circRNAs) and micro-RNAs (miRNAs) for the prevention and treatment of cardiovascular diseases. The genetic environment that contributes to atherosclerosis pathophysiology is immensely complex. Any potential therapeutic application of circRNAs must be assessed for risks, benefits, and off-target effects in both the short and long term. A search of the online PubMed database for publications related to circRNA and atherosclerosis from 2016 to 2022 was conducted. These studies were reviewed for their design, including methods for developing atherosclerosis and the effects of the corresponding atherosclerotic environment on circRNA expression. Investigated mechanisms were recorded, including associated miRNA, genes, and ultimate effects on cell mechanics, and inflammatory markers. The most investigated circRNAs were then further analyzed for redundant, disparate, and/or contradictory findings. Many disparate, opposing, and contradictory effects were observed across experiments. These include levels of the expression of a particular circRNA in atherosclerotic environments, attempted ascertainment of the in toto effects of circRNA or miRNA silencing on atherosclerosis progression, and off-target, cell-specific, and disease-specific effects. The high potential for detrimental and unpredictable off-target effects downstream of circRNA manipulation will likely render the practice of therapeutic targeting of circRNA or miRNA molecules not only complicated but perilous.

CircRnas in atherosclerosis, with special emphasis on the spongy effect of circRnas on miRnas

Atherosclerosis (AS) is a chronic inflammatory disease, which leads to atherosclerotic rupture, lumen stenosis and thrombosis, and often endangers life. Circular RNAs (circRNAs) are a special class of non-coding RNA molecules, whose abnormal expression has been proved to be closely related to human diseases, including AS. Both the abnormal regulation of circRNAs and the sponging effect on miRNAs would lead to changes in gene expression in the form of epigenetic modification, ultimately leading to the formation of AS. CircRNAs can be used as peripheral blood markers of AS, and play an important regulatory role in the proliferation, migration, inflammation and apoptosis of vascular smooth muscle cells, endothelial cells and macrophage, which are key cells for the development of AS. The in-depth understanding of circRNAs in AS not only provides a new method for the diagnosis of AS, but also provides a new idea for the treatment of AS.

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.

Circular RNAs in diabetes and its complications: Current knowledge and future prospects

A novel class of non-coding RNA transcripts called circular RNAs (circRNAs) have been the subject of significant recent studies. Accumulating evidence points that circRNAs play an important role in the cellular processes, inflammatory expression, and immune responses through sponging miRNA, binding, or translating in proteins. Studies have found that circRNAs are involved in the physiologic and pathologic processes of diabetes. There has been an increased focus on the relevance of between abnormal circRNA expression and the development and progression of various types of diabetes and diabetes-related diseases. These circRNAs not only serve as promising diagnostic and prognostic molecular biomarkers, but also have important biological roles in islet cells, diabetes, and its complications. In addition, many circRNA signaling pathways have been found to regulate the occurrence and development of diabetes. Here we comprehensively review and discuss recent advances in our understanding of the physiologic function and regulatory mechanisms of circRNAs on pancreatic islet cells, different subtypes in diabetes, and diabetic complications.

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.

DOCK9 antisense RNA2 interacts with LIN28B to stabilize Wnt5a and boosts proliferation and migration of oxidized low densitylipoprotein-induced vascular smooth muscle cells

Study has suggested that long non-coding RNA DOCK9 antisense RNA2 (LncRNA DOCK9-AS2) may play an important role in atherosclerosis, but the specific role is unclear. In this article, we aim to explore the role and mechanism of DOCK9-AS2 in the proliferation and migration of vascular smooth muscle cells (VSMCs) in atherosclerosis. VSMCs were treated with oxidized low densitylipoprotein (ox-LDL) for 24 h to establish the model of atherosclerosis in vitro. Gain- and loss-of function experiments were conducted. Cell Counting Kit-8 (CCK-8) assay and Ki67 staining were used to evaluate the ability cell proliferation. Transwell assay and immunofluorescence staining of N-Cadherin and E-cadherin were carried out to detect cell migration. RNA immunoprecipitation (RIP) experiment, pull down assay and mRNA stability analysis were used to assess the relationship of DOCK9-AS2, Wnt5a and LIN28B. Western blot analysis was used to measure the protein expression levels. The results showed that DOCK9-AS2 knockdown inhibited the proliferation and migration of ox-LDL-induced VSMCs. Further study on the interaction between DOCK9-AS2, Wnt5a and LIN28B revealed that LIN28B could both directly interact with DOCK9-AS2 and Wnt5a, and DOCK9-AS2 regulated Wnt5a by targeting LIN28B. In addition, Overexpression of Wnt5a partly abolished the inhibitory effects of LIN28B knockdown or DOCK9-AS2 knockdown on cell proliferation and migration induced by in ox-LDL-induced proliferation and migration. In conclusion, the results showed that DOCK9-AS2 promoted the proliferation and migration of vascular smooth muscle cells in atherosclerosis through regulating Wnt5a by targeting LIN28B.

The progress and challenges of circRNA for diabetic foot ulcers: A mini-review

Since the Human Genome Project was successfully completed, humanity has entered a post-genome era, and the second-generation sequencing technology has gradually progressed and become more accurate. Meanwhile, circRNAs plays a crucial role in the regulation of diseases and potential clinical applications has gradually attracted the attention of physicians. However, the mechanisms of circRNAs regulation at the cellular and molecular level of diabetic foot ulcer (DFU) is still not well-understood. With the deepening of research, there have been many recent studies conducted to explore the effect of circRNAs on DFU. In this mini-review, we discuss the potential role of circRNAs as therapeutic targets and diagnostic markers for DFU in order to gain a better understanding of the molecular mechanisms that underlie the development of DFU and to establish a theoretical basis for accurate treatment and effective prevention.

Noncoding RNAs and RNA-binding proteins in diabetic wound healing

Poor wound healing is a common complication in diabetic patients. It often leads to intractable infections and lower limb amputations and is associated with cardiovascular morbidity and mortality. NcRNAs, which can regulate gene expression, have emerged as important regulators of various physiological processes. Herein, we summarize the diverse roles of ncRNAs in the key stages of diabetic wound healing, including inflammation, angiogenesis, re-epithelialization, and extracellular matrix remodeling. Meanwhile, the potential use of ncRNAs as novel therapeutic targets for wound healing in diabetic patients is also discussed. In addition, we summarize the role of RNA-binding proteins (RBPs) in the regulation of gene expression and signaling pathways during skin repair, which may provide opportunities for therapeutic intervention for this potentially devastating disease. However, so far, research on the modulated drug based on ncRNAs that lead to significantly altered gene expression in diabetic patients is scarce. We have compiled some drugs that may be able to modulate ncRNAs, which significantly regulate the gene expression in diabetic patients.

Circular RNAs in the Regulation of Oxidative Stress

Oxidative stress caused by an imbalance between the production and elimination of reactive metabolites and free radicals can lead to the development of a variety of diseases. Over the past years, with the development of science and technology, circular RNA (circRNA) has been found to be closely associated with oxidative stress, which plays an important role in the process of oxidative stress. Currently, the understanding of circRNAs in the mechanism of oxidative stress is limited. In this review, we described the relationship between oxidative stress and circRNAs, the circRNAs related to oxidative stress, and the role of circRNAs in promoting or inhibiting the occurrence and development of diseases associated with the oxidative stress system.

Circular RNA Expression: Its Potential Regulation and Function in Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) have posed a great threat to human life, and the necessity of its monitoring and treatment is decided by symptomatology and/or the aneurysm size. Accumulating evidence suggests that circular RNAs (circRNAs) contribute a part to the pathogenesis of AAAs. circRNAs are novel single-stranded RNAs with a closed loop structure and high stability, having become the candidate biomarkers for numerous kinds of human disorders. Besides, circRNAs act as molecular "sponge" in organisms, capable of regulating the transcription level. Here, we characterize that the molecular mechanisms underlying the role of circRNAs in AAA development were further elucidated. In the present work, studies on the biosynthesis, bibliometrics, and mechanisms of action of circRNAs were aims comprehensively reviewed, the role of circRNAs in the AAA pathogenic mechanism was illustrated, and their potential in diagnosing AAAs was examined. Moreover, the current evidence about the effects of circRNAs on AAA development through modulating endothelial cells (ECs), macrophages, and vascular smooth muscle cells (VSMCs) was summarized. Through thorough investigation, the molecular mechanisms underlying the role of circRNAs in AAA development were further elucidated. The results demonstrated that circRNAs had the application potential in the diagnosis and prevention of AAAs in clinical practice. The study of circRNA regulatory pathways would be of great assistance to the etiologic research of AAAs.

High glucose suppresses autophagy through the AMPK pathway while it induces autophagy via oxidative stress in chondrocytes

Diabetes (DB) is a risk factor for osteoarthritis progression. High glucose (HG) is one of the key pathological features of DB and has been demonstrated to induce apoptosis and senescence in chondrocytes. Autophagy is an endogenous mechanism that can protect cells against apoptosis and senescence. The effects of HG on autophagy in cells including chondrocytes have been studied; however, the results have been inconsistent. The current study aimed to elucidate the underlying mechanisms, which could be associated with the contrasting outcomes. The present study revealed that HG can induce apoptosis and senescence in chondrocytes, in addition to regulating autophagy dynamically. The present study demonstrated that HG can cause oxidative stress in chondrocytes and suppress the AMPK pathway in a dose-dependent manner. Elimination of oxidative stress by Acetylcysteine, also called N-acetyl cysteine (NAC), downregulated autophagy and alleviated HG-stimulated apoptosis and senescence, while activation of the AMPK signaling pathway by AICAR not only upregulated autophagy but also alleviated HG-stimulated apoptosis and senescence. A combined treatment of NAC and AICAR was superior to treatment with either NAC or AICAR. The study has demonstrated that HG can suppress autophagy through the AMPK pathway and induce autophagy via oxidative stress in chondrocytes.

The Role of Non-coding RNAs in Diabetic Nephropathy-Related Oxidative Stress

Diabetic nephropathy (DN) is one of the main complications of diabetes and the main cause of diabetic end-stage renal disease, which is often fatal. DN is usually characterized by progressive renal interstitial fibrosis, which is closely related to the excessive accumulation of extracellular matrix and oxidative stress. Non-coding RNAs (ncRNAs) are RNA molecules expressed in eukaryotic cells that are not translated into proteins. They are widely involved in the regulation of biological processes, such as, chromatin remodeling, transcription, post-transcriptional modification, and signal transduction. Recent studies have shown that ncRNAs play an important role in the occurrence and development of DN and participate in the regulation of oxidative stress in DN. This review clarifies the functions and mechanisms of ncRNAs in DN-related oxidative stress, providing valuable insights into the prevention, early diagnosis, and molecular therapeutic targets of DN.

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.

Emerging Clues of Regulatory Roles of Circular RNAs through Modulating Oxidative Stress: Focus on Neurological and Vascular Diseases

Circular RNAs (circRNAs) are novel noncoding RNAs that play regulatory roles in gene expression. Dysregulation of circRNAs is associated with the development and progression of several diseases, such as diabetes mellitus, nervous system diseases, cardiovascular diseases, and cancer. CircRNAs functionally participate in cell physiological activities through various molecular mechanisms. However, these molecular mechanisms are unclear. Oxidative stress is an essential factor in the pathogenesis of various diseases, including neurological diseases. Emerging roles of circRNAs have been identified in different systems in response to oxidative stress. In this review, we summarize the current understanding of circRNA biogenesis, properties, expression profiles, and the clues indicating the regulatory roles of circRNAs through oxidative stress in various systems, especially the nervous system.