The roles of non-coding RNAs in vascular calcification and opportunities as therapeutic targets

Functions and application of circRNAs in vascular aging and aging-related vascular diseases

Circular RNAs (circRNAs), constituting a novel class of endogenous non-coding RNAs generated through the reverse splicing of mRNA precursors, possess the capacity to regulate gene transcription and translation. Recently, the pivotal role of circRNAs in controlling vascular aging, as well as the pathogenesis and progression of aging-related vascular diseases, has garnered substantial attention. Vascular aging plays a crucial role in the increased morbidity and mortality of the elderly. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are crucial components of the intima and media layers of the vascular wall, respectively, and are closely involved in the mechanisms underlying vascular aging and aging-related vascular diseases. The review aims to provide a comprehensive exploration of the connection between circRNAs and vascular aging, as well as aging-related vascular diseases. Besides, circRNAs, as potential diagnostic markers or therapeutic targets for vascular aging and aging-related vascular diseases, will be discussed thoroughly, along with the challenges and limitations of their clinical application. Investigating the role and molecular mechanisms of circRNAs in vascular aging and aging-related vascular diseases will provide a novel insight into early diagnosis and therapy, and even effective prognosis assessment of these conditions.

Long Non-Coding RNA Function in Smooth Muscle Cell Plasticity and Atherosclerosis

In the healthy mature artery, vascular cells, including endothelial cells, smooth muscle cells (SMCs), and fibroblasts are organized in different layers, performing specific functions. SMCs located in the media are in a differentiated state and exhibit a contractile phenotype. However, in response to vascular injury within the intima, stimuli from activated endothelial cells and recruited inflammatory cells reach SMCs and induce a series of remodeling events in them, known as phenotypic switching. Indeed, SMCs retain a certain degree of plasticity and are able to transdifferentiate into other cell types that are crucial for both the formation and development of atherosclerotic lesions. Because of their highly cell-specific expression profiles and their widely recognized contribution to physiological and disease-related biological processes, long non-coding RNAs have received increasing attention in atherosclerosis research. Dynamic fluctuations in their expression have been implicated in the regulation of SMC identity. Sophisticated technologies are now available to allow researchers to access single-cell transcriptomes and study long non-coding RNA function with unprecedented precision. Here, we discuss the state of the art of long non-coding RNAs regulation of SMC phenotypic switching, describing the methodologies used to approach this issue and evaluating the therapeutic perspectives of exploiting long non-coding RNAs as targets in atherosclerosis.

Advances in the mechanisms of vascular calcification in chronic kidney disease

Vascular calcification (VC) is common in patients with advanced chronic kidney disease (CKD).A series of factors, such as calcium and phosphorus metabolism disorders, uremic toxin accumulation, inflammation and oxidative stress and cellular senescence, cause osteoblast-like differentiation of vascular smooth muscle cells, secretion of extracellular vesicles, and imbalance of calcium regulatory factors, which together promote the development of VC in CKD. Recent advances in epigenetics have provided better tools for the investigation of VC etiology and new approaches for finding more accurate biomarkers. These advances have not only deepened our understanding of the pathophysiological mechanisms of VC in CKD, but also provided valuable clues for the optimization of clinical predictors and the exploration of potential therapeutic targets. The aim of this article is to provide a comprehensive overview of the pathogenesis of CKD VC, especially the new advances made in recent years, including the various key factors mentioned above. Through the comprehensive analysis, we expect to provide a solid theoretical foundation and research direction for future studies targeting the specific mechanisms of CKD VC, the establishment of clinical predictive indicators and the development of potential therapeutic strategies.

Transglutaminase 2 regulates endothelial cell calcification via IL-6-mediated autophagy

Introduction

Endothelial cell (EC) calcification is an important marker of atherosclerotic calcification. ECs play a critical role not only in atherogenesis but also in intimal calcification, as they have been postulated to serve as a source of osteoprogenitor cells that initiate this process. While the role of transglutaminase 2 (TG2) in cellular differentiation, survival, apoptosis, autophagy, and cell adhesion is well established, the mechanism underlying the TG2-mediated regulation of EC calcification is yet to be fully elucidated.

Methods

The TG2 gene was overexpressed or silenced by using siRNA and recombinant adenovirus. RT-PCR and WB were used to analyze the relative expression of target genes and proteins. 5-BP method analyzed TG2 activity. mCherry-eGFP-LC3 adenovirus and transmission electron microscopy analyzed EC autophagy level. Calcium concentrations were measured by using a calcium colorimetric assay kit. Alizarin red S staining assay analyzed EC calcification level. Elisa analyzed IL-6 level. Establishing EC calcification model by using a calcification medium (CM).

Results

Our findings demonstrated that CM increased TG2 activity and expression, which activated the NF-κB signaling pathway, and induced IL-6 autocrine signaling in ECs. Furthermore, IL-6 activated the JAK2/STAT3 signaling pathway to suppress cell autophagy and promoted ECs calcification.

Discussion

ECs are not only critical for atherogenesis but also believed to be a source of osteoprogenitor cells that initiate intimal calcification. Previous research has shown that TG2 plays an important role in the development of VC, but the mechanism by which it exerts this effect is not yet fully understood. Our results demonstrated that TG2 forms complexes with NF-κB components inhibition of autophagy promoted endothelial cell calcification through EndMT. Therefore, our research investigated the molecular mechanism of EC calcification, which can provide new insights into the pathogenesis of atherosclerosis.

A CEBPB/miR-32-5p/GATA6 axis promotes vascular calcification in type 2 diabetes

Vascular calcification in diabetes patients is a major independent risk factor for developing diabetic cardiovascular complications. However, the mechanisms by which diabetes leads to vascular calcification are complex and not yet fully understood. Our previous study revealed that miR-32-5p is a potential new diagnostic marker for coronary artery calcification. In this study, we found that miR-32-5p levels were significantly greater in the plasma of type 2 diabetes patients with coronary artery calcification and were positively correlated with the coronary artery calcification score. In type 2 diabetic mice, miR-32-5p levels were also elevated in the aorta, and knockout of miR-32-5p inhibited the osteogenic differentiation of vascular smooth muscle cells in vivo. Furthermore, overexpression of miR-32-5p promoted vascular smooth muscle cell calcification, while antagonism of miR-32-5p inhibited vascular smooth muscle cell calcification under high-glucose conditions. GATA binding protein 6 (GATA6) was identified as the key target gene through which miR-32-5p promotes vascular smooth muscle cell calcification. Overexpression of GATA6 antagonized the effects of miR-32-5p on vascular calcification. Additionally, high glucose levels were shown to induce the upregulation of miR-32-5p by activating CCAAT/enhancer binding protein beta (CEBPB). These results suggest that miR-32-5p is an important procalcification factor in vascular calcification associated with type 2 diabetes and identify the CEBPB/miR-32-5p/GATA6 axis as a potential biomarker and therapeutic target for preventing and treating vascular calcification in type 2 diabetes.

Relationship between arginine methylation and vascular calcification

In patients on maintenance hemodialysis (MHD), vascular calcification (VC) is an independent predictor of cardiovascular disease (CVD), which is the primary cause of death in chronic kidney disease (CKD). The main component of VC in CKD is the vascular smooth muscle cells (VSMCs). VC is an ordered, dynamic activity. Under the stresses of oxidative stress and calcium-‑phosphorus imbalance, VSMCs undergo osteogenic phenotypic transdifferentiation, which promotes the formation of VC. In addition to traditional epigenetics like RNA and DNA control, post-translational modifications have been discovered to be involved in the regulation of VC in recent years. It has been reported that the process of osteoblast differentiation is impacted by catalytic histone or non-histone arginine methylation. Its function in the osteogenic process is comparable to that of VC. Thus, we propose that arginine methylation regulates VC via many signaling pathways, including as NF-B, WNT, AKT/PI3K, TGF-/BMP/SMAD, and IL-6/STAT3. It might also regulate the VC-related calcification regulatory factors, oxidative stress, and endoplasmic reticulum stress. Consequently, we propose that arginine methylation regulates the calcification of the arteries and outline the regulatory mechanisms involved.

Potential actions of capsaicin for preventing vascular calcification of vascular smooth muscle cells in vitro and in vivo

Vascular calcification (VC) is an accurate risk factor and predictor of adverse cardiovascular events; however, there is currently no effective therapy to specifically prevent VC progression. Capsaicin (Cap) is a bioactive alkaloid isolated from Capsicum annuum L., a traditional medicinal and edible plant that is beneficial for preventing cardiovascular diseases. However, the effect of Cap on VC remains unclear. This study aimed to explore the effects and related mechanisms of Cap on aortic calcification in a mouse and on Pi-induced calcification in vascular smooth muscle cells (VSMCs). First, we established a calcification mouse model with vitamin D3 and evaluated the effects of Cap on calcification mice using von Kossa staining, calcium content, and alkaline phosphatase activity tests. The results showed that Cap significantly improved calcification in mice. VSMCs were then cultured in 2.6 mM Na2HPO4 and 50 μg/mL ascorbic acid for 7 days to obtain a calcification model, and we investigated the effects and mechanisms of Cap on VSMCs calcification by assessing the changes of calcium deposition, calcium content, and subsequent VC biomarkers. These results showed that Cap alleviated VSMCs calcification by upregulating the expressions of TRPV1. Moreover, Cap reduced the expression of Wnt3a and β-catenin, whereas DKK1 antagonised the inhibitory effect of Cap on VSMC calcification. This study is the first to offer direct evidence that Cap inhibits the Wnt/β-catenin signaling pathway by upregulating the expression of the TRPV1 receptor, resulting in the decreased expression of Runx2 and BMP-2, thereby reducing VSMC calcification. Our study may provide novel strategies for preventing the progression of VC. This could serve as a theoretical basis for clinically treating VC with spicy foods.

Network Proteins of Human Sortilin1, Its Expression and Targetability Using Lycopene

BACKGROUND

Sortilin1 (SORT1) is a ubiquitously expressed transporter involved in sorting or clearing proteins and is pathologically linked to tissue fibrosis and calcification. Targeting SORT1 may have potential clinical efficacy in controlling or reversing cardiovascular fibrosis and/or calcification. Hence, this study assessed the protein-protein network of human SORT1 and its targetability using known nutra-/pharmaceuticals.

MATERIAL AND METHODS

Network proteins of human SORT1 were identified using the String database, and the affinity of the protein-protein interaction of this network was analysed using Chimera software (Chimera-1.17.3-mac64). The tissue-specific expression profile of SORT1 was evaluated and assessed for enrichment in different cell types, including immune cells. A library of in-house small molecules and currently used therapeutics for cardiovascular diseases were screened using AutoDock Vina to assess the targetability of human SORT1. The concentration affinity (CA) ratio of the small molecules was estimated to assess the clinical feasibility of targeting SORT1.

RESULTS

IGF2R, NTRK2, GRN and GGA1 were identified as high-affinity interaction networks of SORT1. Of these high-affinity interactions, IGF2R and GRN can be considered relevant networks in regulating tissue fibrosis or the microcalcification process due to their influence on T-cell activation, inflammation, wound repair, and the tissue remodelling process. The tissue cell-type enrichment indicated major expression of SORT1 in adipocytes, specialised epithelial cells, monocytes, cardiomyocytes, and thyroid glandular cells. The binding pocket analysis of human SORT1 showed twelve potential drug interaction sites with varying binding scores (0.86 to 5.83) and probability of interaction (0.004 to 0.304). Five of the drug interaction sites were observed to be targetable at the therapeutically feasible concentration of the small molecules evaluated. Empagliflozin, sitagliptin and lycopene showed a superior affinity and CA ratio compared to established inhibitors of SORT1.

CONCLUSION

IGF2R and GRN are relevant networks of SORT1, regulating tissue fibrosis or the microcalcification process. SORT1 can be targeted using currently approved small-molecule therapeutics (empagliflozin and sitagliptin) or widely used nutraceuticals (lycopene), which should be evaluated in a randomised clinical trial to assess their efficacy in reducing the cardiac/vascular microcalcification process.

Long non-coding RNA MALAT1 sponges miR-30c to promote the calcification of human vascular smooth muscle cells by regulating Runx2

OBJECTIVES

Recent evidence suggested that long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) play critical roles in the pathogenesis of vascular calcification (VC). In this study, we tried to explore the expression and role of a lncRNA, i.e., metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and a miRNA, i.e., miR-30c, in VC.

METHODS

In vitro VC model was induced in human vascular smooth muscle cells (VSMCs) after 10 days culture in calcifying medium containing 2 mM Na₂HPO₄. Alizarin red S staining, calcium assay and western blot analysis of runt-related transcription factor 2 (Runx2) and alpha smooth muscle actin (α-SMA) were performed to evaluate VC. Knockdown of MALAT1 and up-regulation of MALAT1, miR-30c and Runx2 was performed to determine the impact of these molecules on VSMCs calcification. Dual-luciferase report assay was performed to confirm the relationship between MALAT1 and miR-30c or miR-30c and Runx2. In addition, quantitative reverse transcription PCR and western blot were used to determine gene and protein expression.

RESULTS

MALAT1 was increased, while miR-30c was decreased in calcified VSMCs. Knockdown of MALAT1 suppressed VSMCs calcification; on the contrary, up-regulation of MALAT1 promoted VSMCs calcification. The effect of MALAT1 over-expression on VSMCs calcification was reversed by upregulation of miR-30c, which was reversed again by upregulation of Runx2. Dual-luciferase report assay confirmed that there is a direct interaction between MALAT1 and miR-30c, and Runx2 is a direct target of miR-30c.

CONCLUSION

MALAT1 over-expression promoted VSMCs calcification, which was at least partially through regulating the miR-30c/Runx2 axis.

Upregulated LncRNA H19 Sponges MiR-106a-5p and Contributes to Aldosterone-Induced Vascular Calcification via Activating the Runx2-Dependent Pathway

BACKGROUND

Excess aldosterone is implicated in vascular calcification (VC), but the mechanism by which aldosterone-MR (mineralocorticoid receptor) complex promotes VC is unclear. Emerging evidence indicates that long-noncoding RNA H19 (H19) plays a critical role in VC. We examined whether aldosterone-induced osteogenic differentiation of vascular smooth muscle cells (VSMCs) through H19 epigenetic modification of Runx2 (runt-related transcription factor-2) in a MR-dependent manner.

METHODS

We induced in vivo rat model of chronic kidney disease using a high adenine and phosphate diet to explore the relationship among aldosterone, MR, H19, and VC. We also cultured human aortic VSMCs to explore the roles of H19 in aldosterone-MR complex-induced osteogenic differentiation and calcification of VSMCs.

RESULTS

H19 and Runx2 were significantly increased in aldosterone-induced VSMC osteogenic differentiation and VC, both in vitro and in vivo, which were significantly blocked by the MR antagonist spironolactone. Mechanistically, our findings reveal that the aldosterone-activated MR bound to H19 promoter and increased its transcriptional activity, as determined by chromatin immunoprecipitation, electrophoretic mobility shift assay, and luciferase reporter assay. Silencing H19 increased microRNA-106a-5p (miR-106a-5p) expression, which subsequently inhibited aldosterone-induced Runx2 expression at the posttranscriptional level. Importantly, we observed a direct interaction between H19 and miR-106a-5p, and downregulation of miR-106a-5p efficiently reversed the suppression of Runx2 induced by H19 silencing.

CONCLUSIONS

Our study clarifies a novel mechanism by which upregulation of H19 contributes to aldosterone-MR complex-promoted Runx2-dependent VSMC osteogenic differentiation and VC through sponging miR-106a-5p. These findings highlight a potential therapeutic target for aldosterone-induced VC.

Overexpression of microRNA-93-5p and microRNA-374a-5p Suppresses the Osteogenic Differentiation and Mineralization of Human Aortic Valvular Interstitial Cells Through the BMP2/Smad1/5/RUNX2 Signaling Pathway

ABSTRACT

Aortic valve calcification commonly occurs in patients with chronic kidney disease (CKD). However, the regulatory functions of microRNAs (miRNAs/miRs) in the osteogenic differentiation of human aortic valvular interstitial cells (hAVICs) in patients with CKD remain largely unknown. This study aimed to explore the functional role and underlying mechanisms of miR-93-5p and miR-374a-5p in the osteogenic differentiation of hAVICs. For this purpose, hAVICs calcification was induced with high-calcium/high-phosphate medium and the expression levels of miR-93-5p and miR-374a-5p were determined using bioinformatics assay. Alizarin red staining, intracellular calcium content, and alkaline phosphatase activity were used to evaluate calcification. The expression levels of bone morphogenetic protein-2 (BMP2), runt-related transcription factor 2 (Runx2), and phosphorylated (p)-Smad1/5 were detected by luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot analysis. The results revealed that the expression levels of miR-93-5p and miR-374a-5p were significantly decreased in hAVICs in response to high-calcium/high-phosphate medium. The overexpression of miR-93-5p and miR-374a-5p effectively suppressed the high-calcium/high-phosphate-induced calcification and osteogenic differentiation makers. Mechanistically, the overexpression of miR-93-5p and miR-374a-5p inhibits osteogenic differentiation by regulating the BMP2/Smad1/5/Runx2 signaling pathway. Taken together, this study indicates that miR-93-5p and miR-374a-5p suppress the osteogenic differentiation of hAVICs associated with calcium-phosphate metabolic dyshomeostasis through the inhibition of the BMP2/Smad1/5/Runx2 signaling pathway.

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.

Calciphylaxis and its co-occurrence with connective tissue diseases

Calciphylaxis, also known as calcific uremic arteriopathy, is a rare calcification syndrome that presents as ischemic skin necrosis and severe pain. It has a high mortality rate and is characterised by calcification of the small and medium arteries and micro-thrombosis. Calciphylaxis mainly occurs in patients with end-stage renal disease. In recent years, there have been an increasing number of cases of calciphylaxis associated with connective tissue diseases. Given the absence of clear diagnostic criteria for calciphylaxis thus far, an early diagnosis is crucial for designing an effective multidisciplinary treatment plan. In this article, we review the research progress on calciphylaxis and describe its characteristics in the context of connective tissue diseases.

The Landscape of Circular RNAs in Cardiovascular Diseases

Cardiovascular disease (CVD) remains the leading cause of mortality globally. Circular RNAs (circRNAs) have attracted extensive attention for their roles in the physiological and pathological processes of various cardiovascular diseases (CVDs). In this review, we briefly describe the current understanding of circRNA biogenesis and functions and summarize recent significant findings regarding the roles of circRNAs in CVDs. These results provide a new theoretical basis for diagnosing and treating CVDs.

BMF-AS1/BMF Promotes Diabetic Vascular Calcification and Aging both In Vitro and In Vivo

Vascular calcification and aging often increase morbidity and mortality in patients with diabetes mellitus (DM); however, the underlying mechanisms are still unknown. In the present study, we found that Bcl-2 modifying factor (BMF) and BMF antisense RNA 1 (BMF-AS1) were significantly increased in high glucose-induced calcified and senescent vascular smooth muscle cells (VSMCs) as well as artery tissues from diabetic mice. Inhibition of BMF-AS1 and BMF reduced the calcification and senescence of VSMCs, whereas overexpression of BMF-AS1 and BMF generates the opposite results. Mechanistic analysis showed that BMF-AS1 interacted with BMF directly and up-regulated BMF at both mRNA and protein levels, but BMF did not affect the expression of BMF-AS1. Moreover, knocking down BMF-AS1 and BMF suppressed the calcification and senescence of VSMCs, and BMF knockout (BMF^-/-) diabetic mice presented less vascular calcification and aging compared with wild type diabetic mice. In addition, higher coronary artery calcification scores (CACs) and increased plasma BMF concentration were found in patients with DM, and there was a positive correlation between CACs and plasma BMF concentration. Thus, BMF-AS1/BMF plays a key role in promoting high glucose-induced vascular calcification and aging both in vitro and in vivo. BMF-AS1 and BMF represent potential therapeutic targets in diabetic vascular calcification and aging.

Long Non-Coding RNAs as Epigenetic Regulators of Immune Checkpoints in Cancer Immunity

In recent years, cancer treatment has undergone significant changes, predominantly in the shift towards immunotherapeutic strategies using immune checkpoint inhibitors. Despite the clinical efficacy of many of these inhibitors, the overall response rate remains modest, and immunotherapies for many cancers have proved ineffective, highlighting the importance of knowing the tumor microenvironment and heterogeneity of each malignancy in patients. Long non-coding RNAs (lncRNAs) have attracted increasing attention for their ability to control various biological processes by targeting different molecular pathways. Some lncRNAs have a regulatory role in immune checkpoints, suggesting they might be utilized as a target for immune checkpoint treatment. The focus of this review is to describe relevant lncRNAs and their targets and functions to understand key regulatory mechanisms that may contribute in regulating immune checkpoints. We also provide the state of the art on super-enhancers lncRNAs (selncRNAs) and circular RNAs (circRNAs), which have recently been reported as modulators of immune checkpoint molecules within the framework of human cancer. Other feasible mechanisms of interaction between lncRNAs and immune checkpoints are also reported, along with the use of miRNAs and circRNAs, in generating new tumor immune microenvironments, which can further help avoid tumor evasion.

Vaspin alleviates the lncRNA LEF1-AS1-induced osteogenic differentiation of vascular smooth muscle cells via the Hippo/YAP signaling pathway

Vascular calcification (VC) is closely related to higher cardiovascular mortality and morbidity, and vascular smooth muscle cell (VSMC) switching to osteogenic-like cells is crucial for VC. LncRNA LEF1-AS1 promotes atherosclerosis and dental pulp stem cells calcification, while its role in VC remains unknown. Visceral adipose tissue-derived serine protease inhibitor (vaspin) is an adipokine regulating bone metabolism. However, the relationship between vaspin and VC is still unclear. We aimed to explore the role of LEF1-AS1 on VSMC osteogenic transition, whether vaspin inhibited LEF1-AS1-mediated osteogenic differentiation of VSMCs, and the responsible mechanism. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analysis indicated that LEF1-AS1 overexpression significantly upregulated osteogenic marker Runt-related transcription factor-2 (RUNX2) level and downregulated VSMC contractile marker α-smooth muscle actin (α-SMA) level. Alizarin red staining, alkaline phosphatase (ALP) staining, ALP activity assay, and calcium content assay also suggested that LEF1-AS1 overexpression promoted calcium deposition in VSMCs. However, vaspin treatment abolished this phenomenon. Mechanistically, LEF1-AS1 markedly decreased phosphorylated YAP level, while vaspin reversed LEF1-AS1-induced phosphorylated YAP decline. Our results revealed that LEF1-AS1 accelerated the osteogenic differentiation of VSMCs by regulating the Hippo/YAP pathway, while vaspin eliminated the LEF1-AS1-meditated VSMCs osteogenic phenotype switch.

Elucidation of endothelial progenitor cell dysfunction in diabetes by RNA sequencing and constructing lncRNA-miRNA-mRNA competing endogenous RNA network

With the rapid increase in the incidence of diabetes, non-healing diabetic wounds have posed a huge challenge to public health. Endothelial progenitor cell (EPC) has been widely reported to promote wound repairing, while its number and function were suppressed in diabetes. However, the specific mechanisms and competing endogenous RNA (ceRNA) network of EPCs in diabetes remain largely unknown. Thus, the transcriptome analyses were carried in the present study to clarify the mechanism underlying EPCs dysfunction in diabetes. EPCs were successfully isolated from rats. Compared to the control, diabetic rat-derived EPCs displayed impaired proliferation, migration, and tube formation ability. The differentially expressed (DE) RNAs were successfully identified by RNA sequencing in the control and diabetic groups. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that DE mRNAs were significantly enriched in terms and pathways involved in the functions of EPCs and wound healing. Protein-protein interaction networks revealed critical DE mRNAs in the above groups. Moreover, the whole lncRNA-miRNA-mRNA ceRNA network was constructed, in which 9 lncRNAs, 9 mRNAs, and 5 miRNAs were further validated by quantitative real-time polymerase chain reaction. Rno-miR-10b-5p and Tgfb2 were identified as key regulators of EPCs dysfunction in diabetes. The present research provided novel insight into the underlying mechanism of EPCs dysfunction in diabetes and prompted potential targets to restore the impaired functions, thus accelerating diabetic wound healing. KEY MESSAGES: • Compared to the control, diabetic rat-derived EPCs displayed impaired proliferation, migration, and tube formation ability. • The DE RNAs were successfully identified by RNA sequencing in the control and diabetic groups and analyzed by DE, GO, and KEGG analysis. • PPI and lncRNA-miRNA-mRNA ceRNA networks were constructed. • 9 lncRNAs, 9 mRNAs, and 5 miRNAs were further validated by qRT-PCR. • Rno-miR-10b-5p and Tgfb2 were identified as key regulators of EPCs dysfunction in diabetes.

Upregulation of circFOXP1 attenuates inflammation and apoptosis induced by ox-LDL in human umbilical vein endothelial cells by regulating the miR-185-5p/BCL-2 axis

The pathogenesis of coronary artery disease (CAD) is closely related to an abnormal function of the coronary arteries due to myocardial ischemia, hypoxia, or necrosis, which poses a threat to human health. Therefore, this study was conducted to evaluate the role of circFOXP1 in controlling endothelial cell function during atherosclerosis (AS), and further investigate its potential molecular mechanism of regulation. Through Starbase database analysis, we predicted that circFOXP1 can sponge miR-185-5p that targets BCL-2. We found that interleukin (IL)-6, tumor necrois factor (TNF)-α, and IL-1β were significantly upregulated in high-fat diet (HFD)-induced apolipoprotein E-deficient (ApoE-/-) mice compared with those in the control mice. CircFOXP1 was also significantly upregulated in the AS-mice model and AS-cell model. Moreover, miR-185-5p overexpression was found to inhibit BCL-2 protein expression, which consequently reduced the proliferation, and increased the oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs) apoptotic rate. Taken together, our data show that circFOXP1 can further aggravate endothelial cell injury by regulating the miR-185-5p/BCL-2 signal axis.

Noncoding RNAs as a novel approach to target retinopathy of prematurity

Retinopathy of prematurity (ROP), a vascular disease characterized by abnormal vessel development in the retina, has become a primary cause of blindness in children around the world. ROP can be developed during two different phases: vessel loss and vessel proliferation. Once preterm infants with immature retinal vessel growth are exposed to high level of oxygen inside the incubator, vessel loss can occur. When infants are exposed to room air, they may experience the proliferation of vessels in the retina. Although multiple factors are reported to be involved in the pathogenesis of ROP, including vaso-endothelial growth factors (VEGFs) and hypoxia-inducible factors, the pathogenesis of ROP is not completely understood. Although laser therapy and pharmacologic agents, such as anti-VEGF agents, have been commonly used to treat ROP, the incidence of ROP is rapidly rising. Given that current therapies can be invasive and long-term effects are not fully known, the search for novel therapeutic targets with less destructive properties needs to be considered. Within the last decade, the field of noncoding RNA therapy has shown potential as next-generation therapy to treat diverse diseases. In this review, we introduce various noncoding RNAs regulating ROP and discuss their role as potential therapeutic targets in ROP.

Knockdown of hsa_circ_0005699 attenuates inflammation and apoptosis induced by ox-LDL in human umbilical vein endothelial cells through regulation of the miR-450b-5p/NFKB1 axis

Atherosclerosis (AS) remains the leading cause of mortality throughout the world, and vascular endothelial cell dysfunction is one of the key events leading to this pathology. In recent years, there has been an increased interest in the role of circulating RNAs in various diseases; these noncoding RNAs can regulate gene products by acting as microRNA (miR) sponges. Furthermore, it has been shown that foam cells exhibit high expression levels of hsa_circ_0005699 (circ_0005699); however, to the best of our knowledge, no previous study has investigated the role of circ_0005699 in the regulation of vascular endothelial function. The present study employed human umbilical vein endothelial cells (HUVECs), which have been widely used to study vascular endothelial cell function. In addition, apolipoprotein E (ApoE)-deficient mice were used, which have been shown to rapidly develop AS and are widely used as a model of this disease. Cellular and biochemical techniques were performed, including gene transfection and short hairpin RNA-mediated gene silencing for cell transfection, luciferase reporter gene assay to confirm predicted genes, Cell Counting Kit-8 assay and flow cytometry to assess cell viability and apoptosis, and reverse transcription-quantitative PCR and western blotting for detection of mRNA and protein expression. In the present study, the expression levels of circ_0005699 were increased by oxidized low-density lipoprotein in a time- and dose-dependent manner in HUVECs; this was also associated with increased apoptosis of these cells. In addition, the expression levels of circ_0005699 were elevated, along with increased levels of inflammatory cytokines, in ApoE-deficient mice. An RNA pull-down assay indicated that circ_0005699 can bind miR-450b-5p to decrease its expression, whereas silencing of circ_0005699 resulted in increased expression of miR-450b-5p. In addition, the online bioinformatics tool starBase predicted NFKB1 as a target gene of miR-450b-5p, which was further confirmed by the luciferase reporter gene assay. Notably, knockdown of circ_0005699 resulted in the increased survival of HUVECs, which was associated with decreased protein expression levels of NFKB1 and inflammatory cytokines. By contrast, the effects of circ-0005699 silencing on survival were reversed by miR-450b-5p inhibition or NFKB1 overexpression. In conclusion, knockdown of circ_0005699 may ameliorate endothelial cell injury through regulation of the miR-450b-5P/NFKB1 signaling axis.

New Aspects on the Treatment of Retinopathy of Prematurity: Currently Available Therapies and Emerging Novel Therapeutics

Retinopathy of prematurity (ROP) is a rare proliferative ocular disorder in preterm infants. Because of the advancements in neonatal care, the incidence of ROP has increased gradually. Now, ROP is one of the leading causes of blindness in children. Preterm infants with immature retinal development are exposed to supplemental oxygen inside an incubator until their cardiopulmonary system is adequately developed. Once they are returned to room air, the relatively low oxygen level stimulates various angiogenesis factors initiating retinal neovascularization. If patients with ROP are not offered adequate and timely treatment, they can experience vision loss that may ultimately lead to permanent blindness. Although laser therapy and anti-vascular endothelial growth factor agents are widely used to treat ROP, they have limitations. Thus, it is important to identify novel therapeutics with minimal adverse effects for the treatment of ROP. To date, various pharmacologic and non-pharmacologic therapies have been assessed as treatments for ROP. In this review, the major molecular factors involved in the pathogenesis of ROP, currently offered therapies, therapies under investigation, and emerging novel therapeutics of ROP are discussed.

Contribution of FBLN5 to Unstable Plaques in Carotid Atherosclerosis via mir128 and mir532-3p Based on Bioinformatics Prediction and Validation

FBLN5, a member of the short fibulins in the fibulin family of extracellular matrix/matricellular proteins, is involved in interactions with components of the basement membrane and extracellular matrix proteins. It plays key roles in endothelial tissues in many vascular diseases. In this study, the relationship between FBLN5 and carotid atherosclerotic plaque stability as well as the regulatory roles of miRNAs were evaluated. Differential gene expression analyses and weighted gene co-expression network analysis (WGCNA) based on the GSE163154 dataset (including 16 samples without intraplaque hemorrhage and 27 samples with intraplaque hemorrhage) in GEO revealed that FBLN5 is related to plaque stability and is the most significantly differentially expressed gene. LASSO regression was used to evaluate genes obtained from the intersection of differentially expressed genes and clinically significant modules identified by WGCNA. A prediction model based on eight genes, including FBLN5, was constructed and showed an accuracy of 0.951 based on an ROC analysis. Low FBLN5 expression in plaque tissues was confirmed by immunohistochemistry and western blotting. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses showed that FBLN5 acted mainly by the maintenance of the cellular matrix and reactive oxygen species production. miRNAs upstream of these eight predictive genes, including FBLN5, were identified and used to construct a network diagram. These results revealed that hsa-mir-128 and hsa-mir-532-3p were upstream regulatory factors of FBLN5, as verified by PCR assays of human plaque tissues demonstrating that both miRNAs were significantly up-regulated. Therefore, FBLN5 may play an important role in carotid atherosclerosis via hsa-mir-128 and hsa-mir-532-3p as well as become an essential target for treatment.

Circular RNA circSmoc1-2 regulates vascular calcification by acting as a miR-874-3p sponge in vascular smooth muscle cells

Vascular calcification (VC), or calcium deposition inside the blood vessels, is common in patients with atherosclerosis, cardiovascular disease, and chronic kidney disease. Although several treatments are available to reduce calcification, the incidence of VC continues to rise. Recently, there have been several reports describing the regulation of circular RNAs (circRNAs) in various diseases. However, the role of circRNAs in VC has not yet been fully explored. Here, we investigated the function of circSmoc1-2, one of the circRNAs generated from the Smoc1 gene, which is downregulated in response to VC. CircSmoc1-2 is localized primarily to the cytoplasm and is resistant to exonuclease digestion. Inhibition of circSmoc1-2 worsens VC, while overexpression of circSmoc1-2 reduces VC, suggesting that circSmoc1-2 can prevent calcification. We went on to investigate the mechanism of circSmoc1-2 as a microRNA sponge and noted that miR-874-3p, the predicted target of circSmoc1-2, promotes VC, while overexpression of circSmoc1-2 reduces VC by suppressing miR-874-3p. Additionally, we identified the potential mRNA target of miR-874-3p as Adam19. In conclusion, we revealed that the circSmoc1-2/miR-874-3p/Adam19 axis regulates VC, suggesting that circSmoc1-2 may be a novel therapeutic target in the treatment of VC.

Non-coding RNA-based regulation of inflammation

Inflammation is a multifactorial process and various biological mechanisms and pathways participate in its development. The presence of inflammation is involved in pathogenesis of different diseases such as diabetes mellitus, cardiovascular diseases and even, cancer. Non-coding RNAs (ncRNAs) comprise large part of transcribed genome and their critical function in physiological and pathological conditions has been confirmed. The present review focuses on miRNAs, lncRNAs and circRNAs as ncRNAs and their potential functions in inflammation regulation and resolution. Pro-inflammatory and anti-inflammatory factors are regulated by miRNAs via binding to 3'-UTR or indirectly via affecting other pathways such as SIRT1 and NF-κB. LncRNAs display a similar function and they can also affect miRNAs via sponging in regulating levels of cytokines. CircRNAs mainly affect miRNAs and reduce their expression in regulating cytokine levels. Notably, exosomal ncRNAs have shown capacity in inflammation resolution. In addition to pre-clinical studies, clinical trials have examined role of ncRNAs in inflammation-mediated disease pathogenesis and cytokine regulation. The therapeutic targeting of ncRNAs using drugs and nucleic acids have been analyzed to reduce inflammation in disease therapy. Therefore, ncRNAs can serve as diagnostic, prognostic and therapeutic targets in inflammation-related diseases in pre-clinical and clinical backgrounds.

MicroRNAs in Valvular Heart Diseases: Biological Regulators, Prognostic Markers and Therapeutical Targets

miRNAs have recently attracted investigators' interest as regulators of valvular diseases pathogenesis, diagnostic biomarkers, and therapeutical targets. Evidence from in-vivo and in-vitro studies demonstrated stimulatory or inhibitory roles in mitral valve prolapse development, aortic leaflet fusion, and calcification pathways, specifically osteoblastic differentiation and transcription factors modulation. Tissue expression assessment and comparison between physiological and pathological phenotypes of different disease entities, including mitral valve prolapse and mitral chordae tendineae rupture, emerged as the best strategies to address miRNAs over or under-representation and thus, their impact on pathogeneses. In this review, we discuss the fundamental intra- and intercellular signals regulated by miRNAs leading to defects in mitral and aortic valves, congenital heart diseases, and the possible therapeutic strategies targeting them. These miRNAs inhibitors are comprised of antisense oligonucleotides and sponge vectors. The miRNA mimics, miRNA expression vectors, and small molecules are instead possible practical strategies to increase specific miRNA activity. Advantages and technical limitations of these new drugs, including instability and complex pharmacokinetics, are also presented. Novel delivery strategies, such as nanoparticles and liposomes, are described to improve knowledge on future personalized treatment directions.

Crosstalk between Heart Failure and Cognitive Impairment via hsa-miR-933/RELB/CCL21 Pathway

Background

The association between heart failure (HF) and cognitive impairment has received increasing attention from scholars and researchers in recent years. However, no systematic studies have been carried out yet focused on the crosstalk between heart failure and cognitive impairment via miRNAs.

Methods

GSE104150, GSE53473, GSE120584, and GSE116250 with RNA-seq data and clinical data were downloaded from the GSE database. All data were statistically analysed using R software to detect DE-miRNAs and DE-mRNAs associated with both HF and cognitive impairment. Protein-protein interaction (PPI) networks were mapped, and a logistic regression model for cognitive impairment prediction was developed. Furthermore, the TTRUST database and miRWalk were used to map miRNA-transcription factor (TF) and messenger RNA (mRNA) regulatory pathways. Finally, core TFs were enriched for analysis.

Results

Differentially enriched DE-miRNAs and DE-mRNAs both present in HF and cognitive impairment were determined. A logistic regression model established based on DE-miRNAs was validated to have a strong performance in cognitive impairment prediction. The core miRNA-TF-mRNA pathway was formed by mapping the PPI networks associated with the two diseases. Further GSEA was performed with V-rel reticuloendotheliosis viral oncogene homolog B (RELB) as the core TF, and the retinol metabolism and gap junction pathways were analysed.

Conclusions

This study was the first attempt to predict the crosstalk and examine underlying mechanisms between HF and cognitive impairment applying bioinformatics. The findings suggested a potential hsa-miR-933/RELB/CCL21 regulatory axis correlated with HF and neurological disorders (or cognitive impairment), according to PPI networks.

Non-coding RNAs: The key regulators in NLRP3 inflammasome-mediated inflammatory diseases

Inflammasomes are multiprotein complexes responding to various microbes and endogenous danger signals, contributing to initiating the innate protective response of inflammatory diseases. NLRP3 inflammasome is a crucial regulator of pro-inflammatory cytokines (IL-1β and IL-18) production through activating caspase-1. Non-coding RNAs (ncRNAs) are a class of RNA transcripts lacking the ability to encode peptides or proteins. Its dysregulation leads to the development and progression of inflammation in diseases. Recently, accumulating evidence has indicated that NLRP3 inflammasome activation could be modulated by ncRNAs (lncRNAs, miRNAs, and circRNAs) in a variety of inflammatory diseases. This review focuses on the substantial role and function of ncRNAs in the NLRP3 inflammasome activation, providing novel insight for the future therapeutic approach of inflammatory diseases.

Bibliometric and Visual Analysis of Vascular Calcification Research

Background: Extensive studies related to vascular calcification (VC) were conducted in recent years. However, no bibliometric analysis has systematically investigated this topic. Our study aimed to determine the hotspots and frontiers of VC research in the past decade and provide a reference for future scientific research directions and decision-making in the VC field.

Methods: VC studies were acquired from the Web of Science Core Collection. Bibliometric and visual analyses were performed using CiteSpace, VOSviewer, and Microsoft Excel software.

Results: A total of 8,238 English articles on VC research published in 2011–2020 were obtained. In the past decade, annual publications and citations showed a significant growth trend, especially in 2018–2020. The most productive country, institution, journal and author are the United States, the University of California System, PLOS ONE, and Budoff MJ, respectively. The most frequently cited country, journal, and author are the United States, Journal of the American College of Cardiology, and Floege J, respectively. “Vascular calcification,” “atherosclerosis,” “chronic kidney disease,” and “cardiovascular disease” are the primary keywords. The burst keywords “revascularization,” “calciprotein particle,” “microRNA,” and “microcalcification” are speculated to be the research frontiers.

Conclusion: The main research hotspots in the VC field are the molecular mechanisms and prognosis of VC in patients with chronic kidney disease or cardiovascular disease. In addition, endovascular therapy and the development of new drugs targeting signal pathways for VC will become the focus of future research. Moreover, non-coding RNAs related to the diagnosis and treatment of VC are great research prospects.

m6A modification promotes miR-133a repression during cardiac development and hypertrophy via IGF2BP2

Both N6-methyladenosine (m6A) RNA modification and microRNAs (miRNAs) are common regulatory mechanisms for gene post-transcription by modulating mRNA stability and translation. They also share the same 3′-untranslated regions (UTRs) regions for their target gene. However, little is known about their potential interaction in cell development and biology. Here, we aimed to investigate how m6A regulates the specific miRNA repression during cardiac development and hypertrophy. Our multiple lines of bioinformatic and molecular biological evidence have shown that m6A modification on cardiac miR-133a target sequence promotes miR-133a repressive effect via AGO2-IGF2BP2 (Argonaute 2—Insulin-like growth factor 2 mRNA binding protein 2) complex. Among 139 cardiac miRNAs, only the seed sequence of miR-133a was inversely complement to m6A consensus motif “GGACH” by sequence alignment analysis. Immunofluorescence staining, luciferase reporter, and m6A-RIP (RNA immunoprecipitation) assays revealed that m6A modification facilitated miR-133a binding to and repressing their targets. The inhibition of the miR-133a on cardiac proliferation and hypertrophy could be prevented by silencing of Fto (FTO alpha-ketoglutarate dependent dioxygenase) which induced m6A modification. IGF2BP2, an m6A binding protein, physically interacted with AGO2 and increased more miR-133a accumulation on its target site, which was modified by m6A. In conclusion, our study revealed a novel and precise regulatory mechanism that the m6A modification promoted the repression of specific miRNA during heart development and hypertrophy. Targeting m6A modification might provide a strategy to repair hypertrophic gene expression induced by miR-133a.

Circular RNA: A novel type of biomarker for glioma (Review)

With the rapid development of sequencing technologies, the characteristics and functions of circular RNAs (circRNAs) in different tissues, and their underlying pathophysiological mechanisms, have been identified. circRNAs are significantly enriched in the brain and are continually expressed from the embryonic stage to the adult stage in rats. Previous studies have reported that certain circRNAs are differentially expressed in glioma and regulate a number of biological processes, such as cell proliferation, metastasis and oncogenesis of glioma. Furthermore, certain circRNAs have been associated with tumor size, World Health Organization tumor grade and poor prognosis in patients with glioma. It has been hypothesized that circRNAs may be involved in the onset and progression of glioma through transcriptional regulation, protein translation and binding to microRNAs. These properties and functions suggest the potential of circRNAs as prognostic biomarkers and therapeutic targets for glioma. For the present review, published studies were examined from PubMed, Embase, Cochrane Central and the reference lists of the retrieved articles. The aim of the present review was to summarize the progress of circRNA research in glioma, discuss the potential diagnostic and prognostic values, and the roles of circRNAs in glioma, and provide a novel theoretical basis and research concepts for the prediction, diagnosis and treatment of glioma.

Circ0083429 Regulates Osteoarthritis Progression via the Mir-346/SMAD3 Axis

Osteoarthritis (OA) is a degenerative joint disease. Currently, apart from symptomatic treatment or joint replacement, no other effective treatments for OA exist. The mechanisms underlying OA remain elusive and require further research. Circular RNAs (circRNAs) are known to be involved in many diseases; however, their function in OA is not yet fully understood. Here, we identified a novel circRNA, Circ0083429. The role of Circ0083429 in OA was confirmed via western blot (WB), quantitative real-time PCR (qRT-PCR), and immunofluorescence (IF) through knockdown and overexpression experiments. The binding of Circ0083429 to downstream miR-346 and its target gene SMAD3 was predicted via bioinformatics analysis and verified using a luciferase reporter assay and RNA pulldown experiments. Finally, the function of Circ0083429 was evaluated in mouse OA models. In our study, we found that Circ0083429 regulates the homeostasis of the extracellular matrix (ECM) in human chondrocytes. Mechanistically, Circ0083429 affects OA by regulating the mRNA level of SMAD3 through the sponging of microRNA (miRNA)-346. Injecting adeno-associated virus Circ0083429 into the intra-junction of the mouse knee alleviated OA. In conclusion, Circ0083429 regulates the ECM via the regulation of the downstream miRNA-346/SMAD3 in human chondrocytes, which provides a new therapeutic strategy for OA.

In silico Prediction of miRNA Interactions With Candidate Atherosclerosis Gene mRNAs

The involvement of genes and miRNAs in the development of atherosclerosis is a challenging problem discussed in recent publications. It is necessary to establish which miRNAs affect the expression of candidate genes. We used known candidate atherosclerosis genes to predict associations. The quantitative characteristics of interactions of miRNAs with mRNA candidate genes were determined using the program, which identifies the localization of miRNA binding sites in mRNA, the free energy interaction of miRNA with mRNA. In mRNAs of GAS6 and NFE2L2 candidate genes, binding sites of 21 miRNAs and of 15 miRNAs, respectively, were identified. In IRS2 mRNA binding sites of 25 miRNAs were located in a cluster of 41 nt. In ADRB3, CD36, FASLG, FLT1, PLA2G7, and PPARGC1A mRNAs, clusters of miR-466, ID00436.3p-miR, and ID01030.3p-miR BS were identified. The organization of overlapping miRNA binding sites in clusters led to their compaction and caused competition among the miRNAs. The binding of 53 miRNAs to the mRNAs of 14 candidate genes with free energy interactions greater than -130 kJ/mole was determined. The miR-619-5p was fully complementary to ADAM17 and CD36 mRNAs, ID01593.5p-miR to ANGPTL4 mRNA, ID01935.5p-miR to NFE2L2, and miR-5096 to IL18 mRNA. Associations of miRNAs and candidate atherosclerosis genes are proposed for the early diagnosis of this disease.