Oxidized low-density lipoprotein accelerates the injury of endothelial cells via circ-USP36/miR-98-5p/VCAM1 axis

Recent advances in the role of hydrogen sulfide in age-related diseases

In recent years, the impact of age-related diseases on human health has become increasingly severe, and developing effective drugs to deal with these diseases has become an urgent task. Considering the essential regulatory role of hydrogen sulfide (H2S) in these diseases, it is regarded as a promising target for treatment. H2S is a novel gaseous transmitter involved in many critical physiological activities, including anti-oxidation, anti-inflammation, and angiogenesis. H2S also regulates cell activities such as cell proliferation, migration, invasion, apoptosis, and autophagy. These regulatory effects of H2S contribute to relieving and treating age-related diseases. In this review, we mainly focus on the pathogenesis and treatment prospects of H2S in regulating age-related diseases.

The prognostic potential of long noncoding RNA XIST in cardiovascular diseases: a review

There is a significant mortality rate associated with cardiovascular disease despite advances in treatment. long Non-coding RNAs (lncRNAs) play a critical role in many biological processes and their dysregulation is associated with a wide range of diseases in which their downstream pathways are disrupted. A lncRNA X-inactive specific transcript (XIST) is well known as a factor that regulates the physiological process of chromosome dosage compensation for females. According to recent studies, lncRNA XIST is involved in a variety of cellular processes, including apoptosis, proliferation, invasion, metastasis, oxidative stress and inflammation, through molecular networks with microRNAs and their downstream targets in neoplastic and non-neoplastic diseases. Because these cellular processes play a role in the pathogenesis of cardiovascular diseases, we aim to investigate the role that lncRNA XIST plays in this process. Additionally, we wish to determine whether it is a prognostic factor or a potential therapeutic target in these diseases.

Investigating the Protein-Based Therapeutic Relationship between Honey Protein SHP-60 and Bevacizumab on Angiogenesis: Exploring the Synergistic Effect through In Vitro and In Silico Analysis

Honey is a natural product produced by honeybees, which has been used not only as food but also as a medicine by humans for thousands of years. In this study, 60 kDa protein was purified from Pakistani Sidr honey named as SHP-60 (Sidr Honey Protein-60), and its antioxidant potential and the effect of Bevacizumab with purified protein on in vitro angiogenesis using human umbilical vein endothelial cells (HUVEC) were investigated. We further validated the molecular protein-protein (SHP-60 with Bevacizumab) interactions through in silico analysis. It showed very promising antioxidant activity by reducing 2,2-diphenyl-1-picrylhydrazyl free radicals with a maximum of 83% inhibition at 50 μM and an IC50 of 26.45 μM statistically significant (**p < 0.01). Angiogenesis is considered a hallmark of cancer, and without it, the tumor cannot grow or metastasize. Bevacizumab, SHP-60, and both in combination were used to treat HUVEC, and the MTT assay was used to assess cell viability. To demonstrate in vitro angiogenesis, HUVEC was grown on Geltrex, and the formation of endotubes was examined using a tube formation assay. HUVEC viability was dose-dependently decreased by Bevacizumab, SHP-60, and both together. Bevacizumab and SHP-60 both inhibited angiogenesis in vitro, and their combination displayed levels of inhibition even higher than those of Bevacizumab alone. We investigated the protein-protein molecular docking interactions and molecular dynamics simulation analysis of MRJP3 (major royal jelly protein 3) similar to SHP-60 in molecular weight with both the heavy chain (HC) and light chain (LC) of Bevacizumab. We found significant interactions between the LC and MRJP3, indicating that ASN468, GLN470, and ASN473 of MRJP3 interact with SER156, SER159, and GLU161 of LC of Bevacizumab. The integration of experimental data and computational techniques is believed to improve the reliability of the findings and aid in future drug design.

MiR-98-5p plays suppressive effects on IL-1β-induced chondrocyte injury associated with osteoarthritis by targeting CASP3

BACKGROUND

This study aims to explore how miR-98-5p affects osteoarthritis, focusing on its role in chondrocyte inflammation, apoptosis, and extracellular matrix (ECM) degradation.

METHODS

Quantitative real-time PCR was used to measure miR-98-5p and CASP3 mRNA levels in OA cartilage tissues and IL-1β-treated CHON-001 cells. We predicted miR-98-5p and CASP3 binding sites using TargetScan and confirmed them via luciferase reporter assays. Chondrocyte viability was analyzed using CCK-8 assays, while pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) were quantified via ELISA. Caspase-3 activity was examined to assess apoptosis, and Western blotting was conducted for protein marker quantification.

RESULTS

Our results showed lower miR-98-5p levels in both OA cartilage and IL-1β-stimulated cells. Increasing miR-98-5p resulted in reduced pro-inflammatory cytokines, decreased caspase-3 activity, and improved cell viability. Furthermore, miR-98-5p overexpression hindered IL-1β-induced ECM degradation, evident from the decline in MMP-13 and β-catenin levels, and an increase in COL2A1 expression. MiR-98-5p's impact on CASP3 mRNA directly influenced its expression. Mimicking miR-98-5p's effects, CASP3 knockdown also inhibited IL-1β-induced inflammation, apoptosis, and ECM degradation. In contrast, CASP3 overexpression negated the suppressive effects of miR-98-5p.

CONCLUSIONS

In conclusion, our data collectively suggest that miR-98-5p plays a protective role against IL-1β-induced damage in chondrocytes by targeting CASP3, highlighting its potential as a therapeutic target for OA.

Circular RNAs: Regulators of endothelial cell dysfunction in atherosclerosis

Endothelial cell (EC) dysfunction is associated with atherosclerosis. Circular RNAs (circRNAs) are covalently closed loops formed by back-splicing, are highly expressed in a tissue-specific or cell-specific manner, and regulate ECs mainly through miRNAs (mircoRNAs) or protein sponges. This review describes the regulatory mechanisms and physiological functions of circRNAs, as well as the differential expression of circRNAs in aberrant ECs. This review focuses on their roles in inflammation, proliferation, migration, angiogenesis, apoptosis, senescence, and autophagy in ECs from the perspective of signaling pathways, such as nuclear factor κB (NF-κB), nucleotide-binding domain, leucine-rich-repeat family, pyrin-domain-containing 3 (NLRP3)/caspase-1, Janus kinase/signal transducer and activator of transcription (JAK/STAT), and phosphoinositide-3 kinase/protein kinase B (PI3K/Akt). Finally, we address the issues and recent advances in circRNAs as well as circRNA-mediated regulation of ECs to improve our understanding of the molecular mechanisms underlying the progression of atherosclerosis and provide a reference for studies on circRNAs that regulate EC dysfunction and thus affect atherosclerosis.

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.

Association of Circular RNAs levels in blood and Essential Hypertension with Carotid Plaque

BACKGROUND

As one of the essential hypertension (EH)-mediated target organ damage, carotid plaque is a crucial subclinical precursor for cardiovascular events. Therefore, it is vital to identify the risk factors and pathogenesis for EH with carotid plaque.

METHODS

Based on our previous microarray analysis, we selected four circRNAs as the candidate circRNAs and detected their expression levels in blood of 192 subjects (64 healthy controls, 64 EH patients, and 64 EH patients with carotid plaque) by qRT-PCR analysis. The regulatory mechanism of circRNAs involved in carotid plaque was predicted by bioinformatics analysis.

RESULTS

The level of hsa_circ_0124782 increased significantly and the levels of hsa_circ_0131618 and hsa_circ_0127342 decreased significantly in the EH group and EH with carotid plaque group compared with the control group (P < .05). Functional enrichment analysis showed that three circRNAs might be implicated in pathogenesis for carotid plaque.

CONCLUSION

Our study revealed the relationship between three circRNAs and carotid plaque, suggesting that they may serve as potential biomarkers for EH with carotid plaque.

MicroRNA-98 inhibition accelerates the development of atherosclerosis via regulation of dysfunction of endothelial cell

BACKGROUND

Atherosclerosis has been recognized as a chronic inflammation initiated by dysfunction of endothelial cell that contributes to the increased morbidity and mortality of severe cardiovascular events. The reported important role of microRNA-98 (miR-98) in regulation of endothelial cell behaviors prompt us to hypothesize that miR-98 could be involved in the process of atherosclerosis.

METHODS AND RESULTS

The current research showed the miR-98 expression was gradually down-regulated in atherosclerotic mouse arteries isolated from ApoE ablation mice subjected to high fat diet. Additionally, a dramatically reduced miR-98 expression in endothelial cells administrated to oxidized low-density lipoprotein (Ox-LDL) but a slight down-regulated level was found in macrophages. Functionally, attenuated miR-98 expression promoted secretion of chemokines and adhesion molecules in human umbilical vein endothelial cells (HUVECs) induced by Ox-LDL, which subsequently increased infiltration and pro-inflammatory genes expression of macrophages, as well as the foam cell formation. Mechanistically, in vitro experiments indicated that the endothelial cell dysfunction regulated by miR-98 knockdown was partially contributed by upregulated expression of HMGB1. Furthermore, the animal experiment with ApoE-/- mice administrated with miR-98 inhibitor demonstrated that miR-98 silencing enhanced the atherosclerotic lesions in aorta and aortic sinus that were accompanied with increased adhesion molecules, chemokines, and pro-inflammatory markers expression.

CONCLUSION

MicroRNA-98 knockdown promoted endothelial cell dysfunction to affect the inflammatory state of macrophage and the development of atherosclerosis, at least partially, through direct targeting HMGB1. Collected, these data suggested that miR-98 could be a novel drug target for atherogenesis management.

Role of Circular RNAs in Atherosclerosis through Regulation of Inflammation, Cell Proliferation, Migration, and Apoptosis: Focus on Atherosclerotic Cerebrovascular Disease

Atherosclerosis (AS) is a disease dangerous to human health and the main pathological cause of ischemic cardiovascular diseases. Although its pathogenesis is not fully understood, numerous basic and clinical studies have shown that AS is a chronic inflammatory disease existing in all stages of atherogenesis. It may be a common link or pathway in the pathogenesis of multiple atherogenic factors. Inflammation is associated with AS complications, such as plaque rupture and ischemic cerebral infarction. In addition to inflammation, apoptosis plays an important role in AS. Apoptosis is a type of programmed cell death, and different apoptotic cells have different or even opposite roles in the process of AS. Unlike linear RNA, circular RNA (circRNA) a covalently closed circular non-coding RNA, is stable and can sponge miRNA, which can affect the stages of AS by regulating downstream pathways. Ultimately, circRNAs play very important roles in AS by regulating inflammation, apoptosis, and some other mechanisms. The study of circular RNAs can provide new ideas for the prediction, prevention, and treatment of AS.

Extracellular vesicles in atherosclerosis and vascular calcification: the versatile non-coding RNAs from endothelial cells and vascular smooth muscle cells

Atherosclerosis (AS) is characterized by the accumulation of lipids, fibrous elements, and calcification in the innermost layers of arteries. Vascular calcification (VC), the deposition of calcium and phosphate within the arterial wall, is an important characteristic of AS natural history. However, medial arterial calcification (MAC) differs from intimal calcification and cannot simply be explained as the consequence of AS. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are directly involved in AS and VC processes. Understanding the communication between ECs and VSMCs is critical in revealing mechanisms underlying AS and VC. Extracellular vesicles (EVs) are found as intercellular messengers in kinds of physiological processes and pathological progression. Non-coding RNAs (ncRNAs) encapsulated in EVs are involved in AS and VC, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). The effects of ncRNAs have not been comprehensively understood, especially encapsulated in EVs. Some ncRNAs have demonstrated significant roles in AS and VC, but it remains unclear the functions of the majority ncRNAs detected in EVs. In this review, we summarize ncRNAs encapsulated in EC-EVs and VSMC-EVs, and the signaling pathways that are involved in AS and VC.

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.

Hsa_circ_0045932 regulates the progression of colorectal cancer by regulating HK2 through sponging miR-873-5p

Background

Circular RNAs (circRNAs) have been confirmed to be key regulators for colorectal cancer (CRC) progression. The purpose of this research was to explore the biological role and mechanism of hsa_circ_0045932 in CRC.

Methods

RT‐qPCR and Western blot (WB) were applied to examine RNA and protein levels, respectively. MTT assay, EdU assay, and transwell assay were used to detect cell proliferative, migration, and invasion. Glucose uptake and lactic acid level were determined to assess cellular glycolysis. Dual‐luciferase reporter and RIP assays were carried out to detect the relationship between miR‐873‐5p and hsa_circ_0045932 or hexokinase 2 (HK2). Xenograft mice model was established to confirm the function of hsa_circ_0045932 in vivo.

Results

Hsa_circ_0045932 was overexpressed in CRC tissue samples and cells. Hsa_circ_0045932 knockdown repressed CRC cell proliferation, invasion, migration, and glycolysis abilities in vitro. MiR‐873‐5p could be sponged by hsa_circ_0045932, and its inhibitor also reversed the inhibitory effect of hsa_circ_0045932 knockdown on CRC cell progression. HK2 was targeted by miR‐873‐5p, and hsa_circ_0045932 regulated HK2 expression through targeting miR‐873‐5p. Overexpression of HK2 reversed the repressive effect of hsa_circ_0045932 knockdown on CRC cell malignant behaviors. Furthermore, the pro‐tumor role of hsa_circ_0045932 in vivo was also confirmed using animal experiments.

Conclusion

Hsa_circ_0045932 promoted CRC progression through sponging miR‐873‐5p to up‐regulate HK2, which might offer novel therapeutic target for CRC clinical intervention.

Mechanisms of Oxidized LDL-Mediated Endothelial Dysfunction and Its Consequences for the Development of Atherosclerosis

Atherosclerosis is an immuno-metabolic disease involving chronic inflammation, oxidative stress, epigenetics, and metabolic dysfunction. There is compelling evidence suggesting numerous modifications including the change of the size, density, and biochemical properties in the low-density lipoprotein (LDL) within the vascular wall. These modifications of LDL, in addition to LDL transcytosis and retention, contribute to the initiation, development and clinical consequences of atherosclerosis. Among different atherogenic modifications of LDL, oxidation represents a primary modification. A series of pathophysiological changes caused by oxidized LDL (oxLDL) enhance the formation of foam cells and atherosclerotic plaques. OxLDL also promotes the development of fatty streaks and atherogenesis through induction of endothelial dysfunction, formation of foam cells, monocyte chemotaxis, proliferation and migration of SMCs, and platelet activation, which culminate in plaque instability and ultimately rupture. This article provides a concise review of the formation of oxLDL, enzymes mediating LDL oxidation, and the receptors and pro-atherogenic signaling pathways of oxLDL in vascular cells. The review also explores how oxLDL functions in different stages of endothelial dysfunction and atherosclerosis. Future targeted pathways and therapies aiming at reducing LDL oxidation and/or lowering oxLDL levels and oxLDL-mediated pro-inflammatory responses are also discussed.

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.

hsa_circ_0000523/miR‑let‑7b/METTL3 axis regulates proliferation, apoptosis and metastasis in the HCT116 human colorectal cancer cell line

Circular RNAs (circRNAs/circs) have gained attention as a class of potential biomarkers for the early detection of multiple cancers. However, the functions and mechanisms of circRNAs in the oncogenesis of human colorectal cancer (CRC) remain to be elucidated. The present study aimed to investigate the roles of hsa_circ_0000523 and its parental gene methyltransferase-like 3 (METTL3) in regulating cell proliferation, apoptosis and invasion in the HCT116 human CRC cell line. To uncover the regulated function of hsa_circ_0000523 in HCT116 cells, a dual-luciferase reporter assay, flow cytometry, reverse transcription-quantitative PCR, Cell Counting Kit-8 assay, cell invasion and western blot assay were used. In HCT116 cells, hsa_circ_0000523 indirectly regulated METTL3 expression by suppressing the transcription of microRNA (miR)-let-7b. The expression of METTL3 promoted cell proliferation and suppressed apoptosis. In the present study, it was found that miR-let-7b promoted cell viability and inhibited apoptosis and invasion, while circ_0000523 exerted the opposite effects. Higher levels of METTL3 expression were associated with more aggressive tumor invasion. The present results suggest that circRNAs and METTL3 may be applied for highly sensitive diagnosis of CRC and for predicting prognosis in patients who have undergone therapy.

Emerging Roles of Extracellular Vesicle-Delivered Circular RNAs in Atherosclerosis

Atherosclerosis (AS) is universally defined as chronic vascular inflammation induced by dyslipidaemia, obesity, hypertension, diabetes and other risk factors. Extracellular vesicles as information transmitters regulate intracellular interactions and their important cargo circular RNAs are involved in the pathological process of AS. In this review, we summarize the current data to elucidate the emerging roles of extracellular vesicle-derived circular RNAs (EV-circRNAs) in AS and the mechanism by which EV-circRNAs affect the development of AS. Additionally, we discuss their vital role in the progression from risk factors to AS and highlight their great potential for use as diagnostic biomarkers of and novel therapeutic strategies for AS.

Possible causes of atherosclerosis: lncRNA COLCA1 induces oxidative stress in human coronary artery endothelial cells and impairs wound healing

Background

Atherosclerosis is the most common cause of cardiovascular disease, accompanied by high mortality and poor prognosis. Low-density lipoprotein (LDL) and its oxidized form oxidized low-density lipoprotein (oxLDL) play an important role in atherosclerosis. This article will explore the role of the lncRNA COLCA1 (colorectal cancer associated 1)/hsa-miR-371a-5p/SPP1 (secreted phosphoprotein 1) pathway in oxLDL in causing human coronary artery endothelial cells (HCAECs) inflammation and related biological function changes.

Methods

OxLDL was used to stimulate HCAECs. The inflammatory response and biological function changes of HCAECs were analyzed, total RNA-seq was performed on HCAECs before and after stimulation, and RT-Qpcr (real-time quantitative PCR) was used to verify the differential genes. Interference of the expression of COLCA1 in HCAECs was performed by siRNA interference technology to verify the role of COLCA1 in the biological function changes of HCAECs after oxLDL stimulation, and further prove that COLCA1 affects SPP1 through hsa-miR-371a-5p.

Results

OxLDL can affect the oxidative stress response of HCAECs, which in turn affects the apoptosis and wound healing ability of HCAECs. COLCA1 and SPP1 were highly expressed after oxLDL stimulation, while hsa-miR-371a-5p was the opposite. After COLCA1 interference, the oxidative stress level of HCAECs stimulated by oxLDL decreased, the apoptosis level also significantly decreased, and the wound healing ability was enhanced. After simultaneous COLCA1 interference and recovery of the expression of hsa-miR-371a-5p, these improved functions disappeared. The dual-luciferase assay confirmed that hsa-miR-371a-5p and COLCA1, hsa-miR-371a-5p and SPP1 has binding targets.

Conclusions

OxLDL can up-regulate the expression of COLCA1 in HCAECs, which in turn affects the intracellular COLCA1/hsa-miR-371a-5p/SPP1 pathway to regulate the level of oxidative stress in cells. This in turn affects the level of apoptosis and wound healing ability, which causes cells to produce a continuous inflammatory response.

Small, Dense Low-Density Lipoprotein-Cholesterol and Atherosclerosis: Relationship and Therapeutic Strategies

Low-density lipoprotein cholesterol (LDL-C) plays an important role in the formation, incidence, and development of atherosclerosis (AS). Low-density lipoproteins can be divided into two categories: large and light LDL-C and small, dense low-density lipoprotein cholesterol (sdLDL-C). In recent years, an increasing number of studies have shown that sdLDL-C has a strong ability to cause AS because of its unique characteristics, such as having small-sized particles and low density. Therefore, this has become the focus of further research. However, the specific mechanisms regarding the involvement of sdLDL-C in AS have not been fully explained. This paper reviews the possible mechanisms of sdLDL-C in AS by reviewing relevant literature in recent years. It was found that sdLDL-C can increase the atherogenic effect by regulating the activity of gene networks, monocytes, and enzymes. This article also reviews the research progress on the effects of sdLDL-C on endothelial function, lipid metabolism, and inflammation; it also discusses its intervention effect. Diet, exercise, and other non-drug interventions can improve sdLDL-C levels. Further, drug interventions such as statins, fibrates, ezetimibe, and niacin have also been found to improve sdLDL-C levels.

Circ_0003204 knockdown protects endothelial cells against oxidized low-density lipoprotein-induced injuries by targeting the miR-491-5p-ICAM1 pathway

Emerging evidence indicates that circular RNA (circRNA) is implicated in the development of atherosclerosis (AS). This study investigated the effect of circ_0003204 on endothelial cell function and explored the functional mechanism of circ_0003204 in AS progression. AS cell models were constructed by treating human umbilical vein endothelial cells (HUVEC) with oxidized low-density lipoprotein (ox-LDL). The expression of circ_0003204 was detected by quantitative real-time PCR (qPCR). The releases of pro-inflammatory factors were determined by ELISA. Cell viability was checked by CCK-8 assay. Cell apoptosis was monitored by flow cytometry assay. The ability of angiogenesis was assessed by tube formation assay. The protein levels of cell development- and apoptosis-related markers were measured by western blot. The binding relationship between miR-491-5p and circ_0003204 or intercellular adhesion molecule 1 (ICAM1) was verified by dual-luciferase reporter assay or RIP assay. The expression of circ_0003204 was strengthened in ox-LDL-treated HUVECs. Circ_0003204 knockdown inhibited ox-LDL-induced inflammation and cell apoptosis, and promoted ox-LDL-depleted cell viability and tube formation ability in HUVECs. MiR-491-5p was a target of circ_0003204, and miR-491-5p directly bound to ICAM1 3'UTR. Accordingly, circ_0003204 positively regulated ICAM1 expression by targeting miR-491-5p. Rescue experiments presented that miR-491-5p inhibition reversed the effects of circ_0003204 knockdown, and ICAM1 overexpression abolished the effects of miR-491-5p restoration. Circ_0003204 knockdown protects HUVECs against ox-LDL-induced injuries by targeting the miR-491-5p-ICAM1 pathway, hinting that circ_0003204 inhibition might prevent AS development.

Circ_USP36 Silencing Attenuates Oxidized Low-Density Lipoprotein-Induced Dysfunction in Endothelial Cells in Atherosclerosis Through Mediating miR-197-3p/ROBO1 Axis

ABSTRACT

Circular RNAs (circRNAs) are reported to play pivotal regulatory roles in atherosclerosis progression. In the present study, we explored the biological role of circRNA ubiquitin-specific peptidase 36 (circ_USP36; hsa_circ_0003204) in oxidized low-density lipoprotein (ox-LDL)-induced dysfunction of endothelial cells (ECs). RNA and protein levels were determined by reverse transcription-quantitative polymerase chain reaction and Western blot assay, respectively. Cell proliferation was analyzed by 5-ethynyl-2'-deoxyuridine assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry was conducted to analyze cell cycle progression and cell apoptosis. The release of tumor necrosis factor α in the supernatant was measured by enzyme linked immunosorbent assay. Cell death was evaluated by lactate dehydrogenase assay. Intermolecular interaction was verified by dual-luciferase reporter assay. Circ_USP36 expression was significantly up-regulated in the serum of atherosclerosis patients and ox-LDL-stimulated HUVECs than that in their corresponding controls. ox-LDL exposure inhibited the proliferation ability and cell cycle progression and triggered the apoptosis and inflammation of HUVECs, and these effects were largely overturned by the knockdown of circ_USP36. microRNA-197-3p (miR-197-3p) was a target of circ_USP36, and circ_USP36 knockdown-mediated protective role in ox-LDL-induced HUVECs was largely counteracted by the silence of miR-197-3p. miR-197-3p interacted with the 3' untranslated region of roundabout guidance receptor 1 (ROBO1). Circ_USP36 knockdown reduced ROBO1 expression partly by up-regulating miR-197-3p in HUVECs. ROBO1 overexpression reversed miR-197-3p accumulation-mediated effects in ox-LDL-induced HUVECs. In conclusion, circ_USP36 interference alleviated ox-LDL-induced dysfunction in HUVECs by targeting miR-197-3p/ROBO1 axis.

A circular RNA, circUSP36, accelerates endothelial cell dysfunction in atherosclerosis by adsorbing miR-637 to enhance WNT4 expression

Atherosclerosis is a fatal disorder that is fundamental to various cardiovascular diseases and severely threatens people’s health worldwide. Several studies have demonstrated the role of circular RNAs (circRNAs) in the pathogenesis of atherosclerosis. circUSP36 acts as a key modulator in the progression of atherosclerosis, but the molecular mechanism underlying this role is as yet unclear. This study aimed to elucidate the mechanism by which circUSP36 exerts its function in an in vitro cell model of endothelial cell dysfunction, which is one of pathological features of atherosclerosis. The circRNA traits of circUSP36 were confirmed, and we observed high expression of circUSP36 in endothelial cells exposed to oxidized low-density lipoprotein (ox-LDL). Functional assays revealed that overexpression of circUSP36 suppressed proliferation and migration of ox-LDL-treated endothelial cells. In terms of its mechanism, circUSP36 adsorbed miR-637 by acting as an miRNA sponge. Moreover, enhanced expression of miR-637 abated the impact of circUSP36 on ox-LDL-treated endothelial cell dysregulation. Subsequently, the targeting relationship between miR-637 and WNT4 was predicted using bioinformatics tools and was confirmed via luciferase reporter and RNA pull-down assays. Notably, depletion of WNT4 rescued circUSP36-mediated inhibition of endothelial cell proliferation and migration. In conclusion, circUSP36 regulated WNT4 to aggravate endothelial cell injury caused by ox-LDL by competitively binding to miR-637; this finding indicates circUSP36 to be a promising biomarker for the diagnosis and therapy of atherosclerosis.

Circular RNAs as Competing Endogenous RNAs in Cardiovascular and Cerebrovascular Diseases: Molecular Mechanisms and Clinical Implications

Circular RNAs (circRNAs) represent a novel class of widespread and diverse endogenous RNA molecules. This unusual class of RNA species is generated by a back-splicing event of exons or introns, resulting in a covalently closed circRNA molecule. Accumulating evidence indicates that circRNA plays an important role in the biological functions of a network of competing endogenous RNA (ceRNA). CircRNAs can competitively bind to miRNAs and abolish the suppressive effect of miRNAs on target RNAs, thus regulating gene expression at the posttranscriptional level. The role of circRNAs as ceRNAs in the pathogenesis of cardiovascular and cerebrovascular diseases (CVDs) has been recently reported and highlighted. Understanding the underlying molecular mechanism could aid the discovery of therapeutic targets or strategies against CVDs. Here, we review the progress in studying the role of circRNAs as ceRNAs in CVDs, with emphasis on the molecular mechanism, and discuss future directions and possible clinical implications.

Gene Expression Profiles of Circular RNAs and MicroRNAs in Chronic Rhinosinusitis With Nasal Polyps

Introduction: Chronic rhinosinusitis (CRS) is often classified primarily on the basis of the absence or presence of nasal polyps (NPs), that is, as CRS with nasal polyps (CRSwNP) or CRS without nasal polyps (CRSsNP). Additionally, according to the percentage of eosinophils, CRSwNP can be further divided into eosinophilic CRSwNP (ECRSwNP) and non-ECRSwNP. CRSwNP is a significant public health problem with a considerable socioeconomic burden. Previous research reported that the pathophysiology of CRSwNP is a complex, multifactorial disease. There have been many studies on its etiology, but its pathogenesis remains unclear. Dysregulated expression of microRNAs (miRNAs) has been shown in psoriasis, rheumatoid arthritis, pulmonary fibrosis, and allergic asthma. Circular RNAs (circRNAs) are also involved in inflammatory diseases such as rheumatoid arthritis, septic acute kidney injury, myocardial ischemia/reperfusion injury, and sepsis-induced liver damage. The function of miRNAs in various diseases, including CRSwNP, is a research hotspot. In contrast, there have been no studies on circRNAs in CRSwNP. Overall, little is known about the functions of circRNAs and miRNAs in CRSwNP. This study aimed to investigate the expression of circRNAs and miRNAs in a CRSwNP group and a control group to determine whether these molecules are related to the occurrence and development of CRSwNP.

Methods: Nine nasal mucosa samples were collected, namely, three ECRSwNP samples, three non-ECRSwNP samples, and three control samples, for genomic microarray analysis of circRNA and microRNA expression. All of the tissue samples were from patients who were undergoing functional endoscopic sinus surgery in our department. Then we selected some differentially expressed miRNAs and circRNAs for qPCR verification. Meanwhile, GO enrichment analysis and KEGG pathway analysis were applied to predict the biological functions of aberrantly expressed circRNAs and miRNAs based on the GO and KEGG databases. Receiver operating characteristic (ROC) curve analysis and principal component analysis (PCA) were performed to confirm these molecules are involved in the occurrence and development of CRSwNP.

Results: In total, 2,875 circRNAs showed significant differential expression in the CRSwNP group. Specifically, 1794 circRNAs were downregulated and 1,081 circRNAs were upregulated. In the CRSwNP group, the expression of 192 miRNAs was significantly downregulated, and none of the miRNAs were significantly upregulated. GO and KEGG analysis showed differential circRNAs and miRNAs were enriched in “amoebiasis,” “salivary secretion,” “pathways in cancer,” and “endocytosis.” Through qRT-PCR verification, the expression profiles of hsa-circ-0031593, hsa-circ-0031594, hsa-miR-132-3p, hsa-miR-145-5p, hsa-miR-146a-5p, and hsa-miR-27b-3p were shown to have statistical differences. In addition, ROC curve analysis showed that the molecules with the two highest AUCs were hsa-circ-0031593 with AUC 0.8353 and hsa-miR-145-5p with AUC 0.8690. Through PCA with the six ncRNAs, the first principal component explained variance ratio was 98.87%. The AUC of the six ncRNAs was 0.8657.

Conclusion: In our study, the expression profiles of ECRSwNP and non-ECRSwNP had no statistical differences. The differentially expressed circRNAs and miRNAs between CRSwNP and control may play important roles in the pathogenesis of CRSwNP. Altered expression of hsa-circ-0031593 and hsa-miR-145-5p have the strongest evidence for involvement in the occurrence and development of CRSwNP because their AUCs are higher than the other molecules tested in this study.