Identification of Differently Expressed mRNAs in Atherosclerosis Reveals CDK6 Is Regulated by circHIPK3/miR-637 Axis and Promotes Cell Growth in Human Vascular Smooth Muscle Cells

Noncoding RNAs in atherosclerosis: regulation and therapeutic potential

Atherosclerosis, a chronic disease of arteries, results in high mortality worldwide as the leading cause of cardiovascular disease. The development of clinically relevant atherosclerosis involves the dysfunction of endothelial cells and vascular smooth muscle cells. A large amount of evidence indicates that noncoding RNAs, such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in various physiological and pathological processes. Recently, noncoding RNAs were identified as key regulators in the development of atherosclerosis, including the dysfunction of endothelial cells, and vascular smooth muscle cells and it is pertinent to understand the potential function of noncoding RNAs in atherosclerosis development. In this review, the latest available research relates to the regulatory role of noncoding RNAs in the progression of atherosclerosis and the therapeutic potential for atherosclerosis is summarized. This review aims to provide a comprehensive overview of the regulatory and interventional roles of ncRNAs in atherosclerosis and to inspire new insights for the prevention and treatment of this disease.

CircHIPK3 targets DRP1 to mediate hydrogen peroxide-induced necroptosis of vascular smooth muscle cells and atherosclerotic vulnerable plaque formation

INTRODUCTION

Necroptosis triggered by H2O2 is hypothesized to be a critical factor in the rupture of atherosclerotic plaques, which may precipitate acute cardiovascular events. Nevertheless, the specific regulatory molecules of this development remain unclear. We aims to elucidate a mechanism from the perspective of circular RNA.

OBJECTIVES

There are few studies on circRNA in VSMCs necroptosis. The objective of our research is to shed light on the intricate roles that circHIPK3 plays in the process of necroptosis in VSMCs and the development of atherosclerotic plaques that are prone to rupture. Our study elucidates the specific molecular mechanisms by which circHIPK3 regulates necroptosis and atherosclerotic vulnerable plaque formation through targeted proteins. Identifying this mechanism at the cellular level offers a molecular framework for understanding plaque progression and stability regulation, as well as a potential biomarker for the prognosis of susceptible atherosclerotic plaques.

METHODS

We collected clinical vascular tissue for HE staining and Masson staining to determine the presence and stability of plaques. Then, NCBI database was used to screen out circRNA with elevated expression level in plaque tissue, and the up-regulated circRNA, circHIPK3, was verified by qRT-PCR and FISH. Further, we synthesized circHIPK3's small interference sequence and overexpressed plasmid in vitro, and verified its regulation effect on necroptosis of VSMCs under physiological and pathological conditions by WB, qRT-PCR and PI staining. Through RNA pull down, mass spectrometry and RNA immunoprecipitation, DRP1 was identified as circHIPK3 binding protein and was positively regulated by circHIPK3. Meanwhile, on the basis of silencing of DRP1, the regulation of circHIPK3 on necroptosis is verified to be mediated by DRP1. Finally, we validated the regulation of circHIPK3 on vulnerable plaque formation in ApoE-/- mice.

RESULTS

We investigated that circHIPK3 was highly expressed in vulnerable plaques, and the increase in expression level promoted H2O2 induced necroptosis of VSMCs. CircHIPK3 targeted the protein DRP1, leading to an elevation in mitochondrial division rate, resulting in increased reactive oxygen species and impaired mitochondrial function, ultimately leading to necroptosis of VSMCs and vulnerable plaque formation.

CONCLUSION

CircHIPK3 interact with DRP1 involve in H2O2 induced Mitochondrial damage and necroptosis of VSMCs, and Silencing circHIPK3 in vivo can reduce atherosclerotic vulnerable plaque formation. Our research findings may have applications in providing diagnostic biomarkers for vulnerable plaques.

Phenotypic and genetic effect of carotid intima-media thickness on the risk of stroke

While carotid intima-media thickness (cIMT) as a noninvasive surrogate measure of atherosclerosis is widely considered a risk factor for stroke, the intrinsic link underlying cIMT and stroke has not been fully understood. We aimed to evaluate the clinical value of cIMT in stroke through the investigation of phenotypic and genetic relationships between cIMT and stroke. We evaluated phenotypic associations using observational data from UK Biobank (N = 21,526). We then investigated genetic relationships leveraging genomic data conducted in predominantly European ancestry for cIMT (N = 45,185) and any stroke (AS, Ncase/Ncontrol=40,585/406,111). Observational analyses suggested an increased hazard of stroke per one standard deviation increase in cIMT (cIMTmax-AS: hazard ratio (HR) = 1.39, 95%CI = 1.09-1.79; cIMTmean-AS: HR = 1.39, 95%CI = 1.09-1.78; cIMTmin-AS: HR = 1.32, 95%CI = 1.04-1.68). A positive global genetic correlation was observed (cIMTmax-AS: [Formula: see text]=0.23, P=9.44 × 10-5; cIMTmean-AS: [Formula: see text]=0.21, P=3.00 × 10-4; cIMTmin-AS: [Formula: see text]=0.16, P=6.30 × 10-3). This was further substantiated by five shared independent loci and 15 shared expression-trait associations. Mendelian randomization analyses suggested no causal effect of cIMT on stroke (cIMTmax-AS: odds ratio (OR)=1.12, 95%CI=0.97-1.28; cIMTmean-AS: OR=1.09, 95%CI=0.93-1.26; cIMTmin-AS: OR=1.03, 95%CI = 0.90-1.17). A putative association was observed for genetically predicted stroke on cIMT (AS-cIMTmax: beta=0.07, 95%CI = 0.01-0.13; AS-cIMTmean: beta=0.08, 95%CI = 0.01-0.15; AS-cIMTmin: beta = 0.08, 95%CI = 0.01-0.16) in the reverse direction MR, which attenuated to non-significant in sensitivity analysis. Our work does not find evidence supporting causal associations between cIMT and stroke. The pronounced cIMT-stroke association is intrinsic, and mostly attributed to shared genetic components. The clinical value of cIMT as a surrogate marker for stroke risk in the general population is likely limited.

Cell death in atherosclerosis

A complex and evolutionary process that involves the buildup of lipids in the arterial wall and the invasion of inflammatory cells results in atherosclerosis. Cell death is a fundamental biological process that is essential to the growth and dynamic equilibrium of all living things. Serious cell damage can cause a number of metabolic processes to stop, cell structure to be destroyed, or other irreversible changes that result in cell death. It is important to note that studies have shown that the two types of programmed cell death, apoptosis and autophagy, influence the onset and progression of atherosclerosis by controlling these cells. This could serve as a foundation for the creation of fresh atherosclerosis prevention and treatment strategies. Therefore, in this review, we summarized the molecular mechanisms of cell death, including apoptosis, pyroptosis, autophagy, necroptosis, ferroptosis and necrosis, and discussed their effects on endothelial cells, vascular smooth muscle cells and macrophages in the process of atherosclerosis, so as to provide reference for the next step to reveal the mechanism of atherosclerosis.

Protein-protein interaction network-based integration of GWAS and functional data for blood pressure regulation analysis

BACKGROUND

It is valuable to analyze the genome-wide association studies (GWAS) data for a complex disease phenotype in the context of the protein-protein interaction (PPI) network, as the related pathophysiology results from the function of interacting polyprotein pathways. The analysis may include the design and curation of a phenotype-specific GWAS meta-database incorporating genotypic and eQTL data linking to PPI and other biological datasets, and the development of systematic workflows for PPI network-based data integration toward protein and pathway prioritization. Here, we pursued this analysis for blood pressure (BP) regulation.

METHODS

The relational scheme of the implemented in Microsoft SQL Server BP-GWAS meta-database enabled the combined storage of: GWAS data and attributes mined from GWAS Catalog and the literature, Ensembl-defined SNP-transcript associations, and GTEx eQTL data. The BP-protein interactome was reconstructed from the PICKLE PPI meta-database, extending the GWAS-deduced network with the shortest paths connecting all GWAS-proteins into one component. The shortest-path intermediates were considered as BP-related. For protein prioritization, we combined a new integrated GWAS-based scoring scheme with two network-based criteria: one considering the protein role in the reconstructed by shortest-path (RbSP) interactome and one novel promoting the common neighbors of GWAS-prioritized proteins. Prioritized proteins were ranked by the number of satisfied criteria.

RESULTS

The meta-database includes 6687 variants linked with 1167 BP-associated protein-coding genes. The GWAS-deduced PPI network includes 1065 proteins, with 672 forming a connected component. The RbSP interactome contains 1443 additional, network-deduced proteins and indicated that essentially all BP-GWAS proteins are at most second neighbors. The prioritized BP-protein set was derived from the union of the most BP-significant by any of the GWAS-based or the network-based criteria. It included 335 proteins, with ~ 2/3 deduced from the BP PPI network extension and 126 prioritized by at least two criteria. ESR1 was the only protein satisfying all three criteria, followed in the top-10 by INSR, PTN11, CDK6, CSK, NOS3, SH2B3, ATP2B1, FES and FINC, satisfying two. Pathway analysis of the RbSP interactome revealed numerous bioprocesses, which are indeed functionally supported as BP-associated, extending our understanding about BP regulation.

CONCLUSIONS

The implemented workflow could be used for other multifactorial diseases.

The potential role and mechanism of circRNAs in foam cell formation

Atherosclerosis is a significant risk factor for coronary heart disease (CHD) and myocardial infarction (MI). Atherosclerosis develops during foam cell generation, which is caused by an imbalance in cholesterol uptake, esterification, and efflux. LOX-1, SR-A1, and CD36 all increased cholesterol uptake. ACAT1 and ACAT2 promote free cholesterol (FC) esterification to cholesteryl esters (CE). The hydrolysis of CE to FC was aided by nCEH. FC efflux was promoted by ABCA1, ABCG1, ADAM10, and apoA-I. SR-BI promotes not only cholesterol uptake but also FC efflux. Circular RNAs (circRNAs), which are single-stranded RNAs with a closed covalent circular structure, have emerged as promising biomarkers and therapeutic targets for atherosclerosis due to their highly tissue, cell, and disease state-specific expression profiles. Numerous studies have shown that circRNAs regulate foam cell formation, acting as miRNA sponges to influence atherosclerosis development by regulating the expression of SR-A1, CD36, ACAT2, ABCA1, ABCG1, ADAM10, apoA-I, SR-B1. Several circRNAs, including circ-Wdr91, circ 0004104, circRNA0044073, circRNA_0001805, circDENND1B, circRSF1, circ 0001445, and circRNA 102682, are potential biomarkers for atherosclerosis to better evaluate cardiovascular risk. It is difficult to deliver synthetic therapeutic circRNAs to the desired target tissues. Nanotechnology, such as GA-RM/GZ/PL, may be an important solution to this problem. In this review, we focus on the potential role and mechanism of circRNA/miRNA axis in foam cell formation in the hopes of discovering new targets for the diagnosis, prevention, and treatment of atherosclerosis.

Circular RNAs Variously Participate in Coronary Atherogenesis

Over the past decade, numerous studies have shown that circular RNAs (circRNAs) play a significant role in coronary artery atherogenesis and other cardiovascular diseases. They belong to the class of non-coding RNAs and arise as a result of non-canonical splicing of premature RNA, which results in the formation of closed single-stranded circRNA molecules that lack 5'-end caps and 3'-end poly(A) tails. circRNAs have broad post-transcriptional regulatory activity. Acting as a sponge for miRNAs, circRNAs compete with mRNAs for binding to miRNAs, acting as competing endogenous RNAs. Numerous circRNAs are involved in the circRNA-miRNA-mRNA regulatory axes associated with the pathogenesis of cardiomyopathy, chronic heart failure, hypertension, atherosclerosis, and coronary artery disease. Recent studies have shown that сirc_0001445, circ_0000345, circ_0093887, сircSmoc1-2, and circ_0003423 are involved in the pathogenesis of coronary artery disease (CAD) with an atheroprotective effect, while circ_0002984, circ_0029589, circ_0124644, circ_0091822, and circ_0050486 possess a proatherogenic effect. With their high resistance to endonucleases, circRNAs are promising diagnostic biomarkers and therapeutic targets. This review aims to provide updated information on the involvement of atherogenesis-related circRNAs in the pathogenesis of CAD. We also discuss the main modern approaches to detecting and studying circRNA-miRNA-mRNA interactions, as well as the prospects for using circRNAs as biomarkers and therapeutic targets for the treatment of cardiovascular diseases.

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.

Circular RNAs in Ischemic Stroke: Biological Role and Experimental Models

Ischemic stroke is among the leading causes of morbidity, disability, and mortality worldwide. Despite the recent progress in the management of acute ischemic stroke, timely intervention still represents a challenge. Hence, strategies to counteract ischemic brain injury during and around the acute event are still lacking, also due to the limited knowledge of the underlying mechanisms. Despite the increasing understanding of the complex pathophysiology underlying ischemic brain injury, some relevant pieces of information are still required, particularly regarding the fine modulation of biological processes. In this context, there is emerging evidence that the modulation of circular RNAs, a class of highly conserved non-coding RNA with a closed-loop structure, are involved in pathophysiological processes behind ischemic stroke, unveiling a number of potential therapeutic targets and possible clinical biomarkers. This paper aims to provide a comprehensive overview of experimental studies on the role of circular RNAs in ischemic stroke.

Circ_0003575 knockdown alleviates ox-LDL-induced human aortic endothelial cell dysfunction in atherosclerosis by miR-637/TRAF6 axis

BACKGROUND

Circular RNAs (circRNAs) are involved in the progression of atherosclerosis (AS). The present study aimed to determine the functions and mechanism of circ_0003575 in AS.

METHODS

Oxidized low-density lipoprotein (ox-LDL) was used to induce human aortic endothelial cells (HAECs) to establish an AS cell model. Cell Counting Kit-8 (CCK-8) assay and 5'-ethynyl-2'-deoxyuridine (EdU) assay were conducted to assess cell proliferation. Flow cytometry analysis was utilized to quantify cell apoptosis. Tube formation assay was performed to analyze angiogenesis ability. Enzyme linked immunosorbent assay (ELISA) was used to examine the concentrations of inflammatory factors. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were manipulated for the expression of circ_0003575, microRNA-637 (miR-637) and TNF receptor associated factor 6 (TRAF6). Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were adopted to estimate the downstream targets of circ_0003575.

RESULTS

Ox-LDL treatment repressed the proliferation and angiogenesis and promoted the apoptosis and inflammation in HAECs. Circ_0003575 knockdown ameliorated ox-LDL-induced injury of HAECs. Circ_0003575 interacted with mi-R-637, which directly targeted TRAF6. Inhibition of miR-637 reversed the impacts of circ_0003575 knockdown on HAEC injury. Moreover, miR-637 overexpression promoted cell proliferation and angiogenesis and inhibited cell apoptosis and inflammation by targeting TRAF6 in ox-LDL-treated HAECs. Further, circ_0003575 silencing inhibited the activation of NF-κB pathway.

CONCLUSION

Circ_0003575 knockdown alleviated ox-LDL-induced HAEC damage by regulating miR-637/TRAF6 and NF-κB pathways.

CircHIPK3 Regulates Vascular Smooth Muscle Cell Calcification Via the miR-106a-5p/MFN2 Axis

Atherosclerosis is the most common arterial disease and is closely related to vascular calcification. CircHIPK3 has been implicated in atherosclerosis development, but the possible downstream regulatory mechanisms remain unclear. The levels of circHIPK3, miR-106a and MFN2 in tissues and blood samples of patients with atherosclerosis were detected by RT-qPCR. The levels of circHIPK3, miR-106a and MFN2 were detected by RT-qPCR and the expression levels of MFN2, osteogenic and cartilage differentiation marker proteins were detected by western blot in vitro. ALP staining, Alizarin Red staining, and calcium content detection evaluated the degree of osteogenic differentiation of cells. Alcian blue staining detected the level of cell cartilage differentiation. Luciferase detected the targeting relationship between circHIPK3 and miR-106a-5p, as well as miR-106a-5p and MFN2. CircHIPK3 and MFN2 were low expressed and miR-106a-5p was highly expressed in tissues and blood samples of patients with atherosclerosis, as well as vascular smooth muscle cell (VSMC) with osteogenic and cartilage differentiation. Overexpression of circHIPK3 reduced the cell mineralization and calcium content. Overexpression of circHIPK3 inhibited osteogenic differentiation by decreasing ALP activity, RUNX2, and OPG expression, and increasing SM22α and SMA level. What's more, overexpression of circHIPK3 decreased the chondrogenic differentiation by inhibiting the protein level of SOX9, aggrecan, and collagen II. CircHIPK3 targeted miR-106a-5p and miR-106a-5p targeted MFN2. MiR-106a-5p overexpression or MFN2 depletion repressed the effect of circHIPK3 overexpression on VSMC calcification. CircHIPK3 regulated osteogenic and cartilage differentiation of VSMC via miR-106a-5p/MFN2 axis, indicating a target for treating vascular calcification.

The Diagnostic and Therapeutic Role of Circular RNA HIPK3 in Human Diseases

Circular RNAs (circRNAs) are a class of noncoding RNAs with closed-loop of single-stranded RNA structure. Although most of the circRNAs do not directly encode proteins, emerging evidence suggests that circRNAs play a pivotal and complex role in multiple biological processes by regulating gene expression. As one of the most popular circRNAs, circular homeodomain-interacting protein kinase 3 (circHIPK3) has frequently gained the interest of researchers in recent years. Accumulating studies have demonstrated the significant impacts on the occurrence and development of multiple human diseases including cancers, cardiovascular diseases, diabetes mellitus, inflammatory diseases, and others. The present review aims to provide a detailed description of the functions of circHIPK3 and comprehensively overview the diagnostic and therapeutic value of circHIPK3 in these certain diseases.

Dysfunction and ceRNA network of the tumor suppressor miR-637 in cancer development and prognosis

MicroRNAs (miRNAs) are a class of small non-coding RNAs ranging from 17 to 25 nt in length. miR-637 is down-regulated in most cancers and up-regulated only in clear cell renal cell carcinoma (ccRCC). miR-637 can target 21 protein-coding genes, which are involved in the regulation of cell growth, cell cycle, cell proliferation, epithelial-mesenchymal transition (EMT), cancer cell invasion and metastasis, etc. In glioma, the transcription factor ZEB2 can bind to the miR-637 promoter region and inhibit miR-637 expression. Besides, miR-637 could be negatively regulated by competing endogenous RNA (ceRNAs) comprising 13 circular RNA (circRNAs) and 9 long non-coding RNA (lncRNAs). miR-637 is involved in regulating five signaling pathways, including the Jak/STAT3, Wnt/β-catenin, PI3K/AKT, and ERK signaling pathways. Low miR-637 expression was significantly associated with larger tumors and later tumor node metastasis (TNM) staging in cancer patients. Low miR-637 expression was also associated with poorer overall survival (OS) in cancer patients such as glioblastoma and low-grade gliomas (GBM/LGG), non-small cell lung cancer (NSCLC), hepatocellular carcinoma (HCC), and ovarian cancer (OV). Low expression of miR-637 increases the resistance of colorectal cancer (CRC) and human cholangiocarcinoma (CHOL) cancer cells to three anticancer chemotherapeutics (gemcitabine (dFdC), cisplatin (DDP), and oxaliplatin (OXA)). Our work summarizes the abnormal expression of miR-637 in various cancers, expounds on the ceRNA regulatory network and signaling pathway involved in miR-637, and summarizes the effect of its abnormal expression on the biological behavior of tumor cells. At the same time, the relationship between the expression levels of miR-637 and its related molecules and the prognosis and pathological characteristics of patients was further summarized. Finally, our work points out the insufficiency of miR-637 in current studies and is expected to provide potential clues for future miR-637-related studies.

Circ_0021155 can participate in the phenotypic transformation of human vascular smooth muscle cells via the miR-4459/TRPM7 axis

The phenotypic transformation of vascular smooth muscle cells (VSMCs) plays a key role in the pathological process of atherosclerosis (AS), and TRPM7 is involved in this process. In this study, we verified whether circRNAs participate in the phenotypic transformation of VSMCs by regulating TRPM7 in AS. The RNA-sequencing data of atherosclerosis were downloaded and analysed from the GEO database. Only hsa_circ_0021155 related to TRPM7 was differentially expressed in AS. circRNA distribution and expression were observed via FISH and PCR. CCK8, scratch test and Transwell assay were used to observe the proliferation and migration of cells. Western blot was performed to examine changes in α-actin, calponin, SMMHC and TRPM7 proteins. The expression of hsa_circ_0021155 against has-miR-4459/miR-3689c was verified via PCR. The ceRNA relationship of TPRM7-miR4459-circ0021155 was verified via dual luciferase assay, and the effects of miR4459 mimic/inhibitor on the proliferation of cells were further observed. The expression of hsa_circ_0021155 and OX-LDL was increased in VSMCs. hsa_circ_0021155 promoted the expression of TRPM7 and inhibited the protein expression of α-actin, calponin and SMMHC. In addition, it promoted the proliferation and migration of cells and inhibited the expression of miR-3689c and miR-4459 but did not affect miR-4756-5p. The dual luciferase assay showed that circ0021155-miR4459-TRPM7 mRNA was highly compatible and could be mutually regulated by a ceRNA network. In conclusion, hsa_circ_0021155 regulates the proliferation, migration and phenotype transformation of VSMCs induced by OX-LDL via the miR-4459/TRPM7 axis. hsa_circ_0021155 and TRPM7 may offer novel therapeutic targets for atherosclerosis.

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.

Identifying causal genes for stroke via integrating the proteome and transcriptome from brain and blood

Background

Genome-wide association studies (GWAS) have revealed numerous loci associated with stroke. However, the underlying mechanisms at these loci in the pathogenesis of stroke and effective stroke drug targets are elusive. Therefore, we aimed to identify causal genes in the pathogenesis of stroke and its subtypes.

Methods

Utilizing multidimensional high-throughput data generated, we integrated proteome-wide association study (PWAS), transcriptome-wide association study (TWAS), Mendelian randomization (MR), and Bayesian colocalization analysis to prioritize genes that contribute to stroke and its subtypes risk via affecting their expression and protein abundance in brain and blood.

Results

Our integrative analysis revealed that ICA1L was associated with small-vessel stroke (SVS), according to robust evidence at both protein and transcriptional levels based on brain-derived data. We also identified NBEAL1 that was causally related to SVS via its cis-regulated brain expression level. In blood, we identified 5 genes (MMP12, SCARF1, ABO, F11, and CKAP2) that had causal relationships with stroke and stroke subtypes.

Conclusions

Together, via using an integrative analysis to deal with multidimensional data, we prioritized causal genes in the pathogenesis of SVS, which offered hints for future biological and therapeutic studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03377-9.

Impact of CircRNAs on Ischemic Stroke

Circular RNA (circRNA) is a recently discovered class of endogenous non-coding RNA that is generated by cyclization, driven by intron pairing, and regulated by related regulators. An important biological function of CircRNA is acting as a molecular sponge to significantly alter miRNA levels over a short period. Several studies have shown that circRNA is closely related to stroke. Therefore, a better understanding of CircRNA function and regulatory mechanism in ischemic brain will help us for the early detection, early diagnosis, and early treatment of stroke. Here, we summary the biological characteristics, expression of circRNA, and its effect on outcome after ischemic stroke.

MicroRNA-375-3p is implicated in carotid artery stenosis by promoting the cell proliferation and migration of vascular smooth muscle cells

Background

Atherosclerosis is the main cause of carotid artery stenosis (CAS) which mostly occurs in the elderly. In this paper, the expression level of miR-375-3p in asymptomatic CAS patients and its diagnostic value for asymptomatic CAS were investigated, and the effects of miR-375-3p on the cell proliferation and migration of vascular smooth muscle cells (VSMCs) was further explored.

Methods

98 healthy subjects and 101 asymptomatic CAS patients were participated in this study. qRT-PCR was used to measure the expression level of serum miR-375-3p, and the ROC curve was established to evaluate the predictive value of miR-375-3p for asymptomatic CAS. After transfection with miR-375-3p mimic or inhibitor in vitro, cell proliferation and migration were detected by CCK-8 assay, colony formation assay, and Transwell assay, respectively. The levels of TNF-α, IL-1β, IL-6 were detected by ELISA. Western blot was used to detect the protein expression of XIAP. Finally, luciferase reporter gene assay was applied to assess the interaction of miR-375-3p with target genes.

Results

The expression level of serum miR-375-3p in asymptomatic CAS patients was significantly higher than that in healthy controls, and the AUC value of ROC curve was 0.888. The sensitivity and specificity were 80.2 and 86.7%, respectively, indicating that miR-375-3p had high diagnostic value for asymptomatic CAS. In vitro cell experiments showed that up-regulation of miR-375-3p significantly promoted the proliferation and migration of VSMCs, and also promoted the generation of inflammatory factors and phenotypic transformation of VSMCs. Luciferase reporter gene assay confirmed that XIAP was a target gene of miR-375-3p and was negatively regulated by miR-375-3p.

Conclusions

In this study, miR-375-3p may have a clinical diagnostic value for asymptomatic CAS patients which need further validation. Increased miR-375-3p levels in CAS may be associated with increased proliferation and migration of VSMCs via downregulation of the apoptosis inducing gene XIAP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02326-6.