Circ-CHFR modulates the proliferation, migration, and invasion of ox-LDL-induced human aorta vascular smooth muscle cells through the miR-214-3p/PAPPA axis

Pregnancy-associated plasma protein-A (PAPP-A) and cardiovascular disease

There is strong evidence that PAPP-A, a local regulator of insulin-like growth factor signaling through proteolytic cleavage of inhibitory binding proteins, is involved in multiple physiological processes associated with cardiovascular disease. This review will describe the various roles of PAPP-A with a focus on atherosclerosis, neointimal hyperplasia, and acute coronary syndrome in animal models and in humans.

Broader Perspective on Atherosclerosis-Selected Risk Factors, Biomarkers, and Therapeutic Approach

Atherosclerotic cardiovascular disease (ASCVD) stands as the leading cause of mortality worldwide. At its core lies a progressive process of atherosclerosis, influenced by multiple factors. Among them, lifestyle-related factors are highlighted, with inadequate diet being one of the foremost, alongside factors such as cigarette smoking, low physical activity, and sleep deprivation. Another substantial group of risk factors comprises comorbidities. Amongst others, conditions such as hypertension, diabetes mellitus (DM), chronic kidney disease (CKD), or familial hypercholesterolemia (FH) are included here. Extremely significant in the context of halting progression is counteracting the mentioned risk factors, including through treatment of the underlying disease. What is more, in recent years, there has been increasing attention paid to perceiving atherosclerosis as an inflammation-related disease. Consequently, efforts are directed towards exploring new anti-inflammatory medications to limit ASCVD progression. Simultaneously, research is underway to identify biomarkers capable of providing insights into the ongoing process of atherosclerotic plaque formation. The aim of this study is to provide a broader perspective on ASCVD, particularly focusing on its characteristics, traditional and novel treatment methods, and biomarkers that can facilitate its early detection.

Crosstalk between ubiquitin ligases and ncRNAs drives cardiovascular disease progression

Cardiovascular diseases (CVDs) are multifactorial chronic diseases and have the highest rates of morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification and quality control of proteins, maintaining intracellular homeostasis via degradation of misfolded, short-lived, or nonfunctional regulatory proteins. Noncoding RNAs (ncRNAs, such as microRNAs, long noncoding RNAs, circular RNAs and small interfering RNAs) serve as epigenetic factors and directly or indirectly participate in various physiological and pathological processes. NcRNAs that regulate ubiquitination or are regulated by the UPS are involved in the execution of target protein stability. The cross-linked relationship between the UPS, ncRNAs and CVDs has drawn researchers' attention. Herein, we provide an update on recent developments and perspectives on how the crosstalk of the UPS and ncRNAs affects the pathological mechanisms of CVDs, particularly myocardial ischemia/reperfusion injury, myocardial infarction, cardiomyopathy, heart failure, atherosclerosis, hypertension, and ischemic stroke. In addition, we further envision that RNA interference or ncRNA mimics or inhibitors targeting the UPS can potentially be used as therapeutic tools and strategies.

Inhibition of circ_0000231 suppresses oxidized low density lipoprotein-induced apoptosis, autophagy and inflammation in human umbilical vein endothelial cells by regulating miR-590-5p/PDCD4 axis

BACKGROUND

Circular RNAs (circRNAs) are the emerging informative RNAs, involved in cardiovascular diseases including atherosclerosis (AS). Endothelial injury is the initial qualitative change of AS. Thus, the objective of this study was to confirm the dysregulation and mechanism of circ_0000231 in cell model of AS at early stage in human umbilical vein endothelial cells (HUVECs) induced by oxidized low-density lipoprotein (ox-LDL).

METHODS

The expression of circ_0000231, miR-590-5p and programmed cell death 4 (PDCD4) was detected using real-time quantitative PCR and western blot. Cell injury was measured with MTT, flow cytometry, caspase-3 activity assay and enzyme-linked immunosorbent assay (ELISA). The interaction among circ_0000231, miR-590-5p and PDCD4 was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assays.

RESULTS

Stress ox-LDL decreased cell viability, and increased apoptosis rate and caspase-3 activity in HUVECs in a dose- and time-dependent manner in concomitant with promotions of interleukin-6, interleukin-1β, tumor necrosis factor-α, LC3-II/I and Beclin-1 levels. Besides, circ_0000231 and PDCD4 expressions were upregulated, and miR-590-5p was downregulated in ox-LDL-stimulated HUVECs. Functionally, knockdown of circ_0000231 and overexpression of miR-590-5p could suppress ox-LDL-elicited above effects on apoptosis, autophagy and inflammatory response, accompanied with PDCD4 downregulation. Physically, miR-590-5p could directly interact with circ_0000231 and PDCD4.

CONCLUSION

Downregulation of circ_0000231 suppresses HUVECs from ox-LDL-induced injury partially through regulating miR-590-5p/PDCD4 axis via competing endogenous RNA mechanism, showing a novel potential target for the pathology and treatment of endothelial injury in AS.

Exploring the Multifaceted Biologically Relevant Roles of circRNAs: From Regulation, Translation to Biomarkers

CircRNAs are a category of regulatory RNAs that have garnered significant attention in the field of regulatory RNA research due to their structural stability and tissue-specific expression. Their circular configuration, formed via back-splicing, results in a covalently closed structure that exhibits greater resistance to exonucleases compared to linear RNAs. The distinctive regulation of circRNAs is closely associated with several physiological processes, as well as the advancement of pathophysiological processes in several human diseases. Despite a good understanding of the biogenesis of circular RNA, details of their biological roles are still being explored. With the steady rise in the number of investigations being carried out regarding the involvement of circRNAs in various regulatory pathways, understanding the biological and clinical relevance of circRNA-mediated regulation has become challenging. Given the vast landscape of circRNA research in the development of the heart and vasculature, we evaluated cardiovascular system research as a model to critically review the state-of-the-art understanding of the biologically relevant functions of circRNAs. We conclude the review with a discussion of the limitations of current functional studies and provide potential solutions by which these limitations can be addressed to identify and validate the meaningful and impactful functions of circRNAs in different physiological processes and diseases.

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.

CIRC_0091822 CONTRIBUTES TO THE PROLIFERATION, INVASION, AND MIGRATION OF VASCULAR SMOOTH MUSCLE CELLS UNDER OXIDIZED LOW-DENSITY LIPOPROTEIN TREATMENT

ABSTRACT

Background: Circular RNAs (circRNAs) have been shown to mediate atherosclerosis (AS) process by regulating vascular smooth muscle cells (VSMCs) function. However, whether circ_0091822 mediates VSMCs function to regulate AS process is unclear. Methods: Oxidized low-density lipoprotein (ox-LDL) was used to treat VSMCs for constructing AS cell models. Vascular smooth muscle cells proliferation, invasion, and migration were examined by cell counting kit 8 assay, EdU assay, transwell assay, and wound healing assay. Protein expression was tested by western blot analysis. The expression of circ_0091822, microRNA (miR)-339-5p, and blocking of proliferation 1 (BOP1) was determined using quantitative real-time PCR. RNA interaction was examined using dual-luciferase reporter assay and RIP assay. Results: Ox-LDL treatment enhanced VSMCs proliferation, invasion, and migration. Circ_0091822 was overexpressed in the serum of AS patients and ox-LDL-induced VSMCs. Circ_0091822 knockdown inhibited ox-LDL-induced VSMCs proliferation, invasion, and migration. Circ_0091822 sponged miR-339-5p, and miR-339-5p inhibitor reversed the function of circ_0091822 knockdown. MiR-339-5p targeted BOP1, and BOP1 also reversed the repressing effect of miR-339-5p on ox-LDL-induced VSMCs functions. Circ_0091822/miR-339-5p/BOP1 axis promoted the activity of Wnt/β-catenin pathway. Conclusions: Circ_0091822 might be a therapeutic target for AS, which facilitated ox-LDL-induced VSMCs proliferation, invasion, and migration through modulating miR-339-5p/BOP1/Wnt/β-catenin pathway.

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.

Regulation of oxidized LDL-induced proliferation and migration in human vascular smooth muscle cells by a novel circ_0007478/miR-638/ROCK2 ceRNA network

BACKGROUND

Circular RNAs (circRNAs) have been implicated in the pathogenesis of atherosclerosis (AS) and the migration and proliferation of vascular smooth muscle cells (VSMCs) under oxidized low-density lipoprotein (ox-LDL). Here, we defined the exact action of human circ_0007478 in VSMC migration and proliferation induced by ox-LDL.

METHODS

Human VSMCs (HVSMCs) were exposed to ox-LDL. Circ_0007478, microRNA (miR)-638, and rho-associated protein kinase 2 (ROCK2) levels were gauged by quantitative real-time PCR (qRT-PCR) and western blot. Cell viability and proliferation were assessed by MTT and EdU assays, respectively. Transwell assays were used to detect cell migration and invasion. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to evaluate the direct relationship between miR-638 and circ_0007478 or ROCK2.

RESULTS

Our data indicated that circ_0007478 expression was augmented in AS serum samples and ox-LDL-treated HVSMCs. Depletion of circ_0007478 attenuated HVSMC proliferation, migration, and invasion induced by ox-LDL. Mechanistically, circ_0007478 targeted miR-638 by directly pairing to miR-638. Reduction of miR-638 reversed the effects of circ_0007478 depletion on ox-LDL-evoked proliferation, migration, and invasion in HVSMCs. ROCK2 was a direct miR-638 target and miR-638-mediated inhibition of ROCK2 relieved ox-LDL-evoked HVSMC proliferation, migration, and invasion. Furthermore, circ_0007478 was identified as a competing endogenous RNA (ceRNA) for miR-638 to modulate ROCK2 expression.

CONCLUSION

Our present study establishes an undescribed ceRNA regulatory network, in which circ_0007478 targets miR-638 to upregulate ROCK2, thereby contributing to ox-LDL-induced proliferation and migration in HVSMCs.

CircSEC11A knockdown alleviates oxidative stress and apoptosis and promotes cell proliferation and angiogenesis by regulating miR-29a-3p/SEMA3A axis in OGD-induced human brain microvascular endothelial cells (HBMECs)

BACKGROUND

Circular RNA (circRNA) has been found to play an important role in the progression of many diseases, including ischemic stroke. However, the regulatory mechanism of circSEC11A in ischemic stroke progression need to further investigation.

METHODS

Human brain microvascular endothelial cells (HBMECs) were stimulated by oxygen glucose deprivation (OGD). CircSEC11A, SEC11A mRNA and miR (microRNA)-29a-3p were quantified by quantitative real-time PCR (qRT-PCR). SEMA3A, BAX and BCL2 protein level was quantified by western blot. Oxidative stress, cell proliferation, angiogenesis and apoptosis abilities were gauged by oxidative stress assay kit, 5-Ethynyl-2'-Deoxyuridine (EdU) staining, tube formation assay and flow cytometry assays, respectively. Direct relationship between miR-29a-3p and circSEC11A or SEMA3A was validated by dual-luciferase reporter assay, RIP assay and RNA pull-down assay.

RESULTS

CircSEC11A was upregulated in OGD-induced HBMECs. OGD promoted the oxidative stress and apoptosis and inhibited cell proliferation and angiogenesis, while circSEC11A knockdown relieved the effects. CircSEC11A functioned as the sponge for miR-29a-3p, and miR-29a-3p inhibitor reversed the effects of si-circSEC11A on OGD-induced HBMECs oxidative injuries. Moreover, SEMA3A served as the target gene of miR-29a-3p. MiR-29a-3p inhibition ameliorated OGD-induced HBMECs oxidative injuries, while SEMA3A overexpression rescued the impacts of miR-29a-3p mimic.

CONCLUSION

CircSEC11A promoted the malignant progression in OGD-induced HBMECs through the mediation of miR-29a-3p/SEMA3A axis. This study has provided the new insight into the underlying application of circSEC11A in cell model of ischemic stroke.

Transcription factor GATA1 represses oxidized-low density lipoprotein-induced pyroptosis of human coronary artery endothelial cells

BACKGROUND

Atherosclerosis (AS) is defined as a chronic inflammatory disorder underly the pathogenesis of cardiovascular diseases (CVDs). Endothelial pyroptosis is associated with AS-like diseases and other CVDs.

OBJECTIVE

This work was designed to expound on the effect of GATA-binding protein 1 (GATA1) on pyroptosis of human coronary artery endothelial cells (HCAECs) in AS.

METHODS

HCAECs were treated with oxidized-low density lipoprotein (ox-LDL) to establish HCAEC injury models. Plasmids for overexpressing GATA1 or silencing retinoic acid-related orphan receptor α (RORα) were transfected into HCAECs. Thereafter, the mRNA levels of GATA1 and RORα in HCAECs were detected using real-time quantitative polymerase chain reaction. HCAEC viability was examined using the cell counting kit-8 method. The levels of pyroptosis-related proteins NOD-like receptor protein 3 (NLRP3), cleaved-Caspase-1, N-terminal of gasdermin D (GSDMD-N), and pyroptosis-related inflammatory cytokines interleukin (IL)-1β and IL-18 were determined using Western blot and enzyme-linked immunosorbent assays, respectively. The targeting relationship between GATA1 and RORα was verified using the chromatin-immunoprecipitation assay. Then, the rescue experiment was conducted to explore the effect of RORα on pyroptosis of ox-LDL-treated HCAECs.

RESULTS

In ox-LDL-treated HCAECs, GATA1 and RORα expressions were decreased, HCAEC viability was reduced, and the levels of NLRP3, cleaved-Caspase1, GSDMD-N, IL-1β, and IL-18 were elevated. GATA1 overexpression increased HCAEC viability and attenuated pyroptosis. GATA1 bound to the RORα promoter region to stimulate RORα transcription, and RORα suppression facilitated ox-LDL-induced pyroptosis of HCAECs.

CONCLUSIONS

GATA1 activated RORα transcription and therefore limited pyroptosis of ox-LDL-treated HCAECs.

Role and mechanism of circular RNA circ_0050486 in regulating oxidized low-density lipoprotein-induced injury in endothelial cells

BACKGROUND

Dysfunction of endothelial cells in the arterial vasculature is an essential contributor to the pathogenesis of atherosclerosis. Circular RNAs (circRNAs) exert important regulatory functions in endothelial cell dysfunction. Here, we explored the precise role and mechanism of circ_0050486 in regulating endothelial cell injury induced by oxidized low-density lipoprotein (ox-LDL).

METHODS

Circ_0050486, microRNA (miR)-182-5p and myeloid differentiation primary response gene 88 (MyD88) were quantified by quantitative real-time PCR or western blot. Cell viability, proliferation and apoptosis were examined by MTS, 5-Ethynyl-2'-Deoxyuridine (EdU), and flow cytometry assays, respectively. Direct relationship between miR-182-5p and circ_0050486 or MYD88 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

Circ_0050486 was upregulated in atherosclerosis serum and ox-LDL-treated human aortic endothelial cells (HAECs). Silencing of circ_0050486 suppressed HAEC injury induced by ox-LDL. Mechanistically, circ_0050486 targeted miR-182-5p, and the effects of circ_0050486 silencing were partially due to the upregulation of miR-182-5p. MYD88 was a direct target of miR-182-5p, and miR-182-5p-mediated inhibition of MYD88 attenuated ox-LDL-evoked HAEC injury. Circ_0050486 bound to miR-182-5p to regulate MYD88 expression. Additionally, the NF-κB signaling pathway was involved in the regulation of circ_0050486/miR-182-5p/MYD88 axis in ox-LDL-treated HAECs.

CONCLUSION

Our study identifies the functional role of circ_0050486 in ox-LDL-induced endogenous cell injury and establishes a mechanism of circ_0050486 function by affecting MYD88 through competitively binding to shared miR-182-5p.

Circ_ARHGAP32 acts as miR-665 sponge to upregulate FGF2 to promote ox-LDL induced vascular smooth muscle cells proliferation and migration

BACKGROUND: Circular RNA (circRNA) is considered to be an important regulator of human diseases, including atherosclerosis (AS). However, the role of circ_ARHGAP32 in AS formation needs further confirmation. OBJECTIVE: To explore the role of circ_ARHGAP32 in AS formation. METHODS: Oxidized low density lipoprotein (ox-LDL) was used to treat vascular smooth muscle cells (VSMCs) to mimic AS cell models in vitro. The expression of circ_ARHGAP32, microRNA (miR)-665, and fibroblast growth factor 2 (FGF2) was analyzed by quantitative real-time PCR. VSMCs function was measured by EdU assay, cell counting kit 8 assay and transwell assay. Protein expression was determined using western blot analysis. Dual-luciferase reporter assay and RNA pull-down assay were performed to verify RNA interaction. RESULTS: Circ_ARHGAP32 was highly expressed in AS patients and ox-LDL-induced VSMCs. Knockdown of circ_ARHGAP32 repressed ox-LDL-induced proliferation and migration in VSMCs. Circ_ARHGAP32 sponged miR-665 to positively regulate FGF2. MiR-665 inhibitor reversed the regulation of sh-circ_ARHGAP32 on ox-LDL-induced VSMCs proliferation and migration. MiR-665 also had a suppressive effect on the proliferation and migration of ox-LDL-induced VSMCs, and this effect could be reversed by FGF2 overexpression. CONCLUSIONS: Circ_ARHGAP32 might be a potential target for AS treatment, which promoted ox-LDL-induced VSMCs proliferation and migration by regulating miR-665/FGF2 network.