Circular non-coding RNA ANRIL modulates ribosomal RNA maturation and atherosclerosis in humans

Multitask learning model for predicting non-coding RNA-disease associations: Incorporating local and global context

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are crucial non-coding RNAs involved in various diseases. Understanding these interactions is vital for advancing diagnostic, preventive, and therapeutic strategies. Existing computational methods often address lncRNA-miRNA-disease associations as isolated tasks, resulting in sparse connections and limited generalizability. Additionally, these ncRNA-disease relationships involve higher-order topological information that is frequently overlooked. To address these challenges, we propose the MTL-NRDA model, which employs a multi-task learning framework to simultaneously predict lncRNA-disease associations, miRNA-disease associations, and lncRNA-miRNA interactions. The model integrates multi-source information through a heterogeneous network encompassing lncRNAs, miRNAs, and disease association networks as well as various similarity networks. Node embeddings are optimized by combining local and global contexts, and local features are aggregated using higher-order graph convolutional networks (HOGCN) to capture ncRNA-disease associations, while global features are extracted via a transformer encoder, effectively handling long-range dependencies. MTL-NRDA uses independent bilinear output layers for each task and dynamically adjusts the loss weights to calculate task-specific association probabilities. Experiments on two independent datasets show that MTL-NRDA outperforms existing models. Ablation studies confirmed the effectiveness of the model components and multi-task strategy, whereas hyperparameter tuning further improved the performance. Case studies on breast and liver cancers demonstrated the practical applicability of the model.

Role of long non-coding RNAs and circular RNAs in kawasaki disease: a systematic review

OBJECTIVE

Previous research has identified the significant roles of non-coding RNAs (ncRNAs) in Kawasaki disease (KD). This systematic review aims to elucidate the involvement and significance of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) in the pathogenesis and progression of KD.

STUDY DESIGN

A systematic search was conducted across four databases (PubMed, Embase, Scopus, and Web of Science) up to June 19, 2023, without year restrictions. The risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

This review included 9 studies encompassing a total of 1894 individuals diagnosed with KD. Seven lncRNAs-Slco4a1, SOCS2-AS1, SRA, HCG22, MHRT, XLOC_006277, and HSD11B1-AS1-were found to be associated with KD, including polymorphisms such as lncRNA rs1814343 C > T and AC008392.1 rs7248320. Additionally, four circRNAs-circRNA-3302, circ7632, circANRIL, and hsa_circ_0123996-were associated with KD.

CONCLUSIONS

Both linear lncRNAs and circRNAs play critical roles in unraveling the mechanisms underlying KD, contributing to biomarker identification and potential therapeutic advances.

Circular RNA biomarkers in cardiovascular disease

Despite medical advancements, heart disease continues to be a primary cause of death globally. While early detection and continuous monitoring are essential for better patient outcomes, current biological markers, such as cardiac troponins and BNP, have shortcomings, including their temporary nature and susceptibility to various factors, such as patient age and other medical conditions. This limitation has motivated scientists to identify new biological indicators and treatment targets that better represent the underlying heart disease mechanisms. Circular RNAs (circRNAs) have recently been identified as key regulatory molecules in various illnesses, including cardiac conditions. These unique noncoding RNA molecules feature a closed circular structure that makes them exceptionally stable and resistant to breakdown. Their durability, specific expression patterns in different tissues, and preservation across species make them promising candidates both as disease markers and potential therapeutic tools for heart conditions. The scientific interest in the role of circRNAs in cardiovascular disease has increased significantly, with studies revealing their involvement in controlling genes and disease development. This comprehensive review examines circRNAs in heart disease, covering their formation, functional mechanisms, and potential clinical applications as disease markers. This paper discusses recent scientific discoveries highlighting their value in diagnosis and prognosis, addresses the difficulties in moving these findings into medical practice and explores future possibilities for the use of circRNAs in heart disease diagnosis and treatment.

ANRIL modulates endothelial senescence and angiogenesis through SASP-driven miR146a regulation in age-related vascular dysfunction

Vascular aging, marked by endothelial cell (EC) dysfunction and compromised angiogenesis, is a central driver of age-related ischemic diseases. Although lncRNAs have emerged as pivotal regulators of endothelial function, their specific roles in endothelial aging remain enigmatic. In this study, we identify the lncRNA ANRIL as a crucial modulator of endothelial dysfunction during aging. By analyzing publicly available lncRNA sequencing datasets comparing young and old ECs, we pinpointed ANRIL and validated its role through a replicative senescence model in human umbilical vein ECs (HUVECs) and FACS sorting of skeletal muscle ECs from aged mice. While ANRIL showed minimal direct effects on angiogenesis, functional assays and transcriptomic analysis revealed its profound impact on the senescence-associated secretory phenotype (SASP). Remarkably, ANRIL regulates the expression of miR146a in ECs, which is transferred to macrophages, where it inhibits VEGF secretion and disrupts endothelial neovascularization. In vivo, ANRIL downregulation in a murine hindlimb ischemia model significantly enhanced neovascularization and restored blood flow, revealing its therapeutic potential for ischemic diseases. These findings position ANRIL as a novel, potent regulator of endothelial senescence, offering new insights into the molecular basis of vascular aging and suggesting ANRIL as a promising therapeutic target to mitigate age-related vascular dysfunction.

LncRNA-induced lysosomal localization of NHE1 promotes increased lysosomal pH in macrophages leading to atherosclerosis

ANRIL, also referred to as CDKN2B-AS1, is a lncRNA gene implicated in the pathogenesis of multiple human diseases including atherosclerotic coronary artery disease, however, definitive in vivo evidence is lacking and the underlying molecular mechanism is largely unknown. In this study, we show that ANRIL overexpression causes atherosclerosis in vivo as transgenic mouse overexpression of full-length ANRIL (NR_003529) increases inflammation and aggravates atherosclerosis under ApoE-/- background (ApoE-/-ANRIL mice). Mechanistically, ANRIL reduces the expression of miR-181b-5p, which leads to increased TMEM106B expression. TMEM106B is significantly up-regulated in atherosclerotic lesions of both human CAD patients and ApoE-/-ANRIL mice. TMEM106B interacts and co-localizes with Na+-H+ exchanger NHE1, which results in mis-localization of NHE1 from cell membranes to lysosomal membranes, leading to increased lysosomal pH in macrophages. Large truncation and point mutation analyses define the critical amino acids for TMEM106B-NHE1 interaction and lysosomal pH regulation as F115 and F117 on TMEM106B and I537, C538, and G539 on NHE1. Topological analysis suggests that both N-terminus and C-terminus of NHE1 are located inside lysosomal lumen, and NHE1 is an important new proton efflux channel involved in raising lysosomal pH. A short TMEM106B peptide (YGRKKRRQRRR-L111A112V113F114F115L116F117) disrupting the TMEM106B-NHE1 interaction normalized lysosomal pH in macrophages with ANRIL overexpression. Our data demonstrate that ANRIL promotes atherosclerosis in vivo and identify the ANRIL/miR-181b-5p/TMEM106B-NHE1/lysosomal pH axis as the underlying molecular pathogenic mechanism for the chromosome 9p21.3 genetic locus for coronary artery disease.

Circular RNAs modulate cell death in cardiovascular diseases

Cardiovascular diseases (CVDs) remain a global health challenge, with programmed cell death (PCD) mechanisms like apoptosis and necroptosis playing key roles in the progression. Circular RNAs (circRNAs) have recently been recognized as crucial regulators of gene expression, especially in modulating PCD. In current researches, circRNA regulation of apoptosis is the most studied area, followed by autophagy and ferroptosis. Notably, the regulatory role of circRNAs in pyroptosis and necroptosis has also begun to attract attention. From a mechanistic perspective, circRNAs influence cellular processes through several modes of action, including miRNA sponging, protein interactions, and polypeptide translation. Manipulating circRNAs and their downstream targets through inhibition or overexpression offers versatile therapeutic options for CVD treatment. Continued investigation into circRNA-mediated mechanisms may enhance our understanding of CVD pathophysiology and underscore their potential as novel and promising therapeutic targets.

SP1 activates AKT3 to facilitate the development of diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus and has the complex pathogenesis. The previous study reported that protein kinase Bγ (AKT3) was involved in DN progression. Our aim was to explore the detailed mechanisms of AKT3 in DN development.

METHODS

RT-qPCR was performed to measure the levels of specificity protein 1 (SP1) and AKT3. Mesangial cells were treated with high glucose (30 mM) to form DN cell model in vitro. Western blot was conducted to detect the protein expression of AKT3, SP1, fibrosis-related proteins, and AKT/mTOR pathway-related proteins. Cell proliferation and inflammation were evaluated via MTT, EdU staining, and ELISA assays, respectively. Oxidative stress was determined via measuring ROS and MDA levels. ChIP and dual-luciferase reporter assays were carried out to verify the relationship between SP1 and AKT3. C57BL/6 mice-treated with streptozotocin for 5 days were used to establish DN mouse model in vivo, and HE and Masson staining were conducted to evaluate pathological changes of mouse kidney tissues.

RESULTS

AKT3 and SP1 were highly expressed in DN kidney tissues and HG-induced mesangial cells. AKT3 depletion could relieve HG treatment-caused cell damage of mesangial cells through repressing cell proliferation, fibrosis, inflammation and oxidative stress. SP1 can bind to the promoter of AKT3 and serve as a translation regulation factor of AKT3. SP1 overexpression worsened HG treatment-caused cell damage of mesangial cells. Moreover, AKT3 upregulation could block the suppressive effects of SP1 depletion on cell proliferation, fibrosis, inflammation and oxidative stress in HG-induced mesangial cells. SP1 depletion reduced AKT3 expression to inactivate the AKT/mTOR pathway in HG-induced mesangial cells. Besides, AKT3 knockdown inhibited the activation of the AKT/mTOR pathway to hamper the development of DN in mice through alleviating fibrosis and inflammation in vivo.

CONCLUSION

Our results indicated that SP1 activated AKT3 and AKT/mTOR pathway to promote mesangial cell proliferation, fibrosis, inflammation and oxidative stress, thereby facilitating DN development.

Myocardial infarction activates the 9p21.3 orthologous locus expression, but its absence does not alter cardiac pathophysiology in ischemia

Genetic variation in the 9p21.3 chromosomal region has one of the strongest associations known for coronary artery disease (CAD) that often leads to myocardial infarction (MI). This risk locus encodes a long noncoding RNA, ANRIL, which has been suggested to regulate the neighboring cyclin-dependent kinase inhibitors 2A and B (Cdkn2A/B), the key regulators of cell proliferation. In this study, we aimed to clarify the role of the 9p21.3 risk locus in acute and chronic myocardial ischemia in mice. Mice carrying a deletion equivalent to the human CAD risk interval (Chr4Δ70kb/Δ70kb) and wild type mice were exposed to MI and followed until 5 days or 4 weeks. In the wild type mice, expression of a lncRNA, Ak148321, was increased after MI, and Cdkn2a was upregulated in chronic ischemia. Chr4Δ70kb/Δ70kb downregulated both Cdkn2a/b, but this did not affect the survival or cardiac pathology after MI. These results suggest that the 9p21.3 locus is activated in response to cardiac ischemia. However, deficiency in the risk locus does not play a role in the cardiac pathophysiology in mice, supporting the studies suggesting the risk locus being more involved in the development of CAD, rather than the subsequent MI.

Quaking-cZFP609 Axis Remedies Aberrant Plasticity of Vascular Smooth Muscle Cells via Mediating Platelet-Derived Growth Factor Receptor β Degradation

Vascular smooth muscle cell (VSMC) plasticity is crucial for the repair after vascular injury. However, the high plasticity of VSMCs may make them transform into pathogenic phenotypes. Here, we show that VSMCs overexpressing Sirtuin 1 (SIRT1) exhibit a reduced phenotypic plasticity in the context of platelet-derived growth factor (PDGF)-BB treatment. SIRT1 activated Quaking (QKI)-cZFP609 axis is involved in the plasticity regulation in the VSMCs. Mechanically, SIRT1 deacetylates K133 and K134 of QKI and mediates its activation. Activated QKI binds the QKI response elements located in the upstream and downstream of the cZFP609-forming exons in ZFP609 pre-mRNA to mediate cZFP609 production. Furthermore, the acetylation of QKI is increased by inhibiting SIRT1 with the selective and potent inhibitor EX527 or deletion of SIRT1, accompanied with parallel decrease in cZFP609 formation. Final, we identify that cZFP609 directs PDGF receptor (PDGFR)β sorting into endosomal/lysosomal pathway and degradation by bridging PDGFRβ and Rab7, resulted in attenuating Raf-MEK-ERK cascade activation downstream of PDGFRβ signaling. Overexpression of cZFP609 remedies aberrant plasticity and overproliferation of VSMCs, and ameliorates neointimal formation. Together, these results highlight that modulating the QKI-cZFP609 axis may help propel repair without stenosis as a therapeutic strategy in vascular injury.

Circular RNAs increase during vascular cell differentiation and are biomarkers for vascular disease

AIMS

The role of circular RNAs (circRNAs) and their regulation in health and disease are poorly understood. Here, we systematically investigated the temporally resolved transcriptomic expression of circRNAs during differentiation of human induced pluripotent stem cells (iPSCs) into vascular endothelial cells (ECs) and smooth muscle cells (SMCs) and explored their potential as biomarkers for human vascular disease.

METHODS AND RESULTS

Using high-throughput RNA sequencing and a de novo circRNA detection pipeline, we quantified the daily levels of 31 369 circRNAs in a 2-week differentiation trajectory from human stem cells to proliferating mesoderm progenitors to quiescent, differentiated EC and SMC. We detected a significant global increase in RNA circularization, with 397 and 214 circRNAs up-regulated greater than two-fold (adjusted P < 0.05) in mature EC and SMC, compared with undifferentiated progenitor cells. This global increase in circRNAs was associated with up-regulation of host genes and their promoters and a parallel down-regulation of splicing factors. Underlying this switch, the proliferation-regulating transcription factor MYC decreased as vascular cells matured, and inhibition of MYC led to down-regulation of splicing factors such as SRSF1 and SRSF2 and changes in vascular circRNA levels. Examining the identified circRNAs in arterial tissue samples and in peripheral blood mononuclear cells (PBMCs) from patients, we found that circRNA levels decreased in atherosclerotic disease, in contrast to their increase during iPSC maturation into EC and SMC. Using machine learning, we determined that a set of circRNAs derived from COL4A1, COL4A2, HSPG2, and YPEL2 discriminated atherosclerotic from healthy tissue with an area under the receiver operating characteristic curve (AUC) of 0.79. circRNAs from HSPG2 and YPEL2 in blood PBMC samples detected atherosclerosis with an AUC of 0.73.

CONCLUSION

Time-resolved transcriptional profiling of linear and circRNA species revealed that circRNAs provide granular molecular information for disease profiling. The identified circRNAs may serve as blood biomarkers for atherosclerotic vascular disease.

Collaborative Duality of CircGLIS3(2) RNA and Protein in human Wound Repair

The discovery of an increasing number of translatable circular RNAs (circRNAs) raises the question of whether their coding and non-coding functions can coexist within the same cell. This study profiles the dynamic expression of circRNAs during human skin wound healing. CircGLIS3(2) is identified, a circRNA whose levels transiently rise in dermal fibroblasts of acute wounds and are abnormally overexpressed in keloids, a fibrotic skin condition. Injury signals such as IL-1α, TGF-β, hypoxia, and ER stress induce both expression and cap-independent translation of CircGLIS3(2). The RNA form of CircGLIS3(2) activates fibroblasts into matrix-secreting cells, while its encoded protein promotes cell proliferation, collectively enhancing wound repair. Mechanistically, CircGLIS3(2) RNA stabilizes the cytoplasmic protein PCOLCE, while its protein binds to BTF3 in the nucleus. Both the RNA and protein are essential for wound closure in human and murine models. CircGLIS3(2)'s bifunctional nature expands its functional spectrum, improving cellular adaptability during environmental changes and offering a promising therapeutic target for wound repair and scar reduction.

Circular RNAs exhibit exceptional stability in the aging brain and serve as reliable age and experience indicators

Circular RNAs (circRNAs) increase in the brain with age across various animal systems. To elucidate the reasons behind this phenomenon, we profile circRNAs from fly heads at six time points throughout their lifespan. Our results reveal a linear increase in circRNA levels with age, independent of changes in mRNA levels, overall transcription, intron retention, or host gene splicing, demonstrating that the age-related accumulation is due to high stability rather than increased biogenesis. This remarkable stability suggests that circRNAs can serve as markers of environmental experience. Indeed, flies exposed to a 10-day regimen at 29°C exhibit higher levels of specific circRNAs even 6 weeks after returning to standard conditions, indicating that circRNAs can reveal past environmental stimuli. Moreover, half-life measurements show circRNA stability exceeding 20 days, with some displaying virtually no degradation. These findings underscore the remarkable stability of circRNAs in vivo and their potential as markers for stress and life experiences.

Circ_0000190 inhibits the progression of triple negative breast cancer by regulating miR-301a/MEOX2 pathway

Circular RNA (circRNA) and microRNA (miRNA) play critical roles in regulating proliferation, apoptosis, and invasion in triple-negative breast cancer (TNBC) cells. To investigate their functional significance, we employed quantitative real-time PCR (qRT-PCR) to assess the differential expression of circ_0000190, miR-301a, and mesenchyme homeobox 2 (MEOX2) between TNBC cell lines and normal breast epithelial cells. Subsequently, we established overexpression and knockdown systems for these molecules to examine their effects on TNBC cell proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition (EMT). Additionally, we evaluated the impact of circ_0000190 overexpression on tumor growth using a mouse xenograft model, measuring tumor volume and weight. Our findings revealed that circ_0000190 and MEOX2 expression were significantly downregulated (P<0.05) in TNBC cells compared to normal breast epithelial cells, whereas miR-301a was upregulated (P<0.05). Knockdown of circ_0000190 promoted TNBC cell proliferation, migration, invasion, and EMT, while suppressing apoptosis. Mechanistically, circ_0000190 functioned as a molecular sponge for miR-301a, and its overexpression significantly inhibited miR-301a expression (P<0.001). Notably, miR-301a mimics partially reversed the suppressive effects of circ_0000190 overexpression on proliferation, migration, invasion, and EMT, as well as its pro-apoptotic effects (P<0.001). Furthermore, we identified MEOX2 as a direct target of miR-301a. MEOX2 knockdown attenuated the inhibitory effects of miR-301a silencing on proliferation, migration, invasion, and EMT, while also counteracting its pro-apoptotic function. In vivo experiments demonstrated that circ_0000190 overexpression significantly reduced tumor volume and weight (P<0.001), concomitant with elevated MEOX2 mRNA and protein levels (P<0.001) and decreased miR-301a expression (P<0.001). In conclusion, our study elucidates that circ_0000190 suppresses TNBC progression by downregulating miR-301a and upregulating MEOX2, forming a competitive endogenous RNA (ceRNA) network of circRNA-miRNA-mRNA.

Targeting Regulatory Noncoding RNAs in Human Cancer: The State of the Art in Clinical Trials

Noncoding RNAs (ncRNAs) are a heterogeneous group of RNA molecules whose classification is mainly based on arbitrary criteria such as the molecule length, secondary structures, and cellular functions. A large fraction of these ncRNAs play a regulatory role regarding messenger RNAs (mRNAs) or other ncRNAs, creating an intracellular network of cross-interactions that allow the fine and complex regulation of gene expression. Altering the balance between these interactions may be sufficient to cause a transition from health to disease and vice versa. This leads to the possibility of intervening in these mechanisms to re-establish health in patients. The regulatory role of ncRNAs is associated with all cancer hallmarks, such as proliferation, apoptosis, invasion, metastasis, and genomic instability. Based on the function performed in carcinogenesis, ncRNAs may behave either as oncogenes or tumor suppressors. However, this distinction is not rigid; some ncRNAs can fall into both classes depending on the tissue considered or the target molecule. Furthermore, some of them are also involved in regulating the response to traditional cancer-therapeutic approaches. In general, the regulation of molecular mechanisms by ncRNAs is very complex and still largely unclear, but it has enormous potential both for the development of new therapies, especially in cases where traditional methods fail, and for their use as novel and more efficient biomarkers. Overall, this review will provide a brief overview of ncRNAs in human cancer biology, with a specific focus on describing the most recent ongoing clinical trials (CT) in which ncRNAs have been tested for their potential as therapeutic agents or evaluated as biomarkers.

The therapeutic potential of circular RNAs

Over the past decade, research into circular RNA (circRNA) has increased rapidly, and over the past few years, circRNA has emerged as a promising therapeutic platform. The regulatory functions of circRNAs, including their roles in templating protein translation and regulating protein and RNA functions, as well as their unique characteristics, such as increased stability and a favourable immunological profile compared with mRNAs, make them attractive candidates for RNA-based therapies. Here, we describe the properties of circRNAs, their therapeutic potential and technologies for their synthesis. We also discuss the prospects and challenges to be overcome to unlock the full potential of circRNAs as drugs.

o8G-modified circPLCE1 inhibits lung cancer progression via chaperone-mediated autophagy

BACKGROUND

Lung cancer poses a serious threat to human health, but its molecular mechanisms remain unclear. Circular RNAs (circRNAs) are closely associated with tumour progression, and the important role of 8-oxoguanine (o8G) modification in regulating the fate of RNA has been gradually revealed. However, o8G modification of circRNAs has not been reported. We identified circPLCE1, which is significantly downregulated in lung cancer, and further investigated the o8G modification of circPLCE1 and the related mechanism in lung cancer progression.

METHODS

We identified differentially expressed circRNAs by RNA high-throughput sequencing and then conducted methylated RNA immunoprecipitation (MeRIP), immunofluorescence (IF) analysis, crosslinking immunoprecipitation (CLIP) and actinomycin D (ActD) assays to explore circPLCE1 o8G modification. The biological functions of circPLCE1 in vivo and in vitro were clarified via establishing a circPLCE1 silencing/overexpression system. Tagged RNA affinity purification (TRAP), RNA Immunoprecipitation (RIP) and coimmunoprecipitation (Co-IP) assays, and pSIN-PAmCherry-KFERQ-NE reporter gene were used to elucidate the molecular mechanism by which circPLCE1 inhibits lung cancer progression.

RESULTS

This study revealed that reactive oxygen species (ROS) can induce circPLCE1 o8G modification and that AUF1 can mediate a decrease in circPLCE1 stability. We found that circPLCE1 significantly inhibited lung cancer progression in vitro and in vivo and that its expression was associated with tumour stage and prognosis. The molecular mechanism was elucidated: circPLCE1 targets the HSC70 protein, increases its ubiquitination level, regulates ATG5-dependent macroautophagy via the chaperone-mediated autophagy (CMA) pathway, and ultimately inhibits lung cancer progression.

CONCLUSION

o8G-modified circPLCE1 inhibits lung cancer progression through CMA to inhibit macroautophagy and alter cell fate. This study provides not only a new theoretical basis for elucidating the molecular mechanism of lung cancer progression but also potential targets for lung cancer treatment.

Mendelian randomization provides a multi-omics perspective on the regulation of genes involved in ribosome biogenesis in relation to cardiac structure and function

BACKGROUND

Ribosome biogenesis (RiboSis) is a complex process for generating ribosomes, the cellular machinery responsible for protein synthesis. Dysfunctional RiboSis can disrupt cardiac structure and function, contributing to cardiovascular diseases. This study employed a Mendelian randomization (MR) approach, integrating multi-omics data, to investigate the relationship between RiboSis-related genes and standard cardiac structure and function.

METHODS

We utilized summary stats for methylation, RNA splicing, and gene expression, and UK Biobank cardiopulm MRI genetic associations (N = 41,135). MR evaluated RiboSis gene features against traits, complemented by hypothesis prioritization for multi-trait colocalization (HyPrColoc) and colocalization. Composite scores ranked RiboSis genes, and phenome-wide association study (PheWAS) with scQTLbase instrumental variables (IVs) confirmed results.

RESULTS

We identified 15 RiboSis-related genes: HEATR1, SENP3, ERI1, ERCC2, TSR1, UTP11, DDX17, SMARCB1, NIP7, ERAL1, NOP56, RPL10A, EIF6, EXOSC9, and NOP58. Notably, HEATR1 and SENP3 were ranked in the top quartile (Q1), scoring 25. In validation cohort, 12 genes associated with cardiac structures, functions, diseases. Only ERAL1, TSR1, and NIP7 lacked significant associations with cardiac traits.

CONCLUSION

Our multi-omics MR analysis identified 15 RiboSis-related genes associated with cardiac risk, with 12 further validated through gene set enrichment analysis. These findings suggest a link between RiboSis and cardiac health, enhancing understanding of cardiac disease mechanisms.

CircXYLT1 suppresses oxidative stress and promotes vascular remodeling in aging mice carotid artery injury model of atherosclerosis via PTBP1

Atherosclerosis and aortic aneurysms are prevalent cardiovascular diseases in the elderly, characterized by chronic inflammation and oxidative stress. This study explores the role of CircXYLT1 in regulating oxidative stress and vascular remodeling in age-related vascular diseases. RNA sequencing revealed a significant upregulation of CircXYLT1 in the vascular tissues of aged mice, highlighting its potential role in age-related vascular diseases. Using a carotid artery wire injury model, we performed adeno-associated virus (AAV)-mediated knockdown and overexpression of CircXYLT1. Key oxidative stress markers, including reactive oxygen species (ROS) and malondialdehyde (MDA), were measured. Knockdown of CircXYLT1 increased oxidative stress and reduced antioxidant protein expression (SOD, GPX), while overexpression led to decreased oxidative damage and enhanced vascular smooth muscle cell (VSMC) proliferation. Mechanistically, CircXYLT1 interacted with PTBP1, reducing its nuclear localization and modulating downstream chemokine signaling pathways. These findings suggest that CircXYLT1 plays a critical role in vascular remodeling and oxidative stress regulation, offering potential as a therapeutic target for managing cardiovascular diseases in aging populations.

Circ-Sirt6 promotes the stability and expression of m6A modified Sirt6 mRNA by recruiting IGF2BP2

Coronary artery disease (CAD) is the leading cause of death worldwide. Even though numerous circRNAs have been linked to the formation and progression of CAD, more circular RNA regulators still need to be uncovered in order to enhance the knowledge of the CAD regulatory networks. Microarray analysis was employed to identify aberrantly expressed circRNAs in vascular pathology, and the level of circ-Sirt6 in abnormally proliferated vascular smooth muscle cells (VSMCs) was detected by qRT-PCR. The effects of circ-Sirt6, IGF2BP2, and Sirt6 on the proliferation and migration of VSMCs were examined by EdU incorporation assay and migration assays. The interaction between circ-Sirt6, IGF2BP2, and Sirt6 was verified by RNA pull-down assay, RIP, FISH, and immunofluorescent staining. Dot blot assay and m6A-methylated RNA immunoprecipitation-qPCR were performed to confirm that circ-Sirt6 promoted m6A modification and stabilization of Sirt6 mRNA. According to our research, circ-Sirt6 expression was markedly downregulated in VSMCs treated with PDGF-BB and carotid artery balloon injury. The in vitro and in vivo proliferation and migration of VSMCs were inhibited by overexpression of circ-Sirt6. Mechanistically, circ-Sirt6 specifically binds to IGF2BP2 and promotes the stability and expression of Sirt6 mRNA by enhancing its m6A modification. Our findings highlight the importance of circ-Sirt6-mediated m6A in VSMC phenotype switching. Circ-Sirt6 may be a novel biological target for CAD.

Exploratory Review and In Silico Insights into circRNA and RNA-Binding Protein Roles in γ-Globin to β-Globin Switching

β-globin gene cluster regulation involves complex mechanisms to ensure proper expression and function in RBCs. During development, switching occurs as γ-globin is replaced by β-globin. Key regulators, like BCL11A and ZBTB7A, repress γ-globin expression to facilitate this transition with other factors, like KLF1, LSD1, and PGC-1α; these regulators ensure an orchestrated transition from γ- to β-globin during development. While these mechanisms have been extensively studied, circRNAs have recently emerged as key contributors to gene regulation, but their role in β-globin gene cluster regulation remains largely unexplored. Although discovered in the 1970s, circRNAs have only recently been recognized for their functional roles, particularly in interactions with RNA-binding proteins. Understanding how circRNAs contribute to switching from γ- to β-globin could lead to new therapeutic strategies for hemoglobinopathies, such as sickle cell disease and β-thalassemia. This review uses the circAtlas 3.0 database to explore circRNA expressions in genes related to switching from γ- to β-globin expression, focusing on blood, bone marrow, liver, and spleen. It emphasizes the exploration of the potential interactions between circRNAs and RNA-binding proteins involved in β-globin gene cluster regulatory mechanisms, further enhancing our understanding of β-globin gene cluster expression.

The role of lncRNAs in the interplay of signaling pathways and epigenetic mechanisms in glioma

Gliomas, highly aggressive tumors of the central nervous system, present overwhelming challenges due to their heterogeneity and therapeutic resistance. Glioblastoma multiforme (GBM), the most malignant form, underscores this clinical urgency due to dismal prognosis despite aggressive treatment regimens. Recent advances in cancer research revealed signaling pathways and epigenetic mechanisms that intricately govern glioma progression, offering multifaceted targets for therapeutic intervention. This review explores the dynamic interplay between signaling events and epigenetic regulation in the context of glioma, with a particular focus on the crucial roles played by non-coding RNAs (ncRNAs). Through direct and indirect epigenetic targeting, ncRNAs emerge as key regulators shaping the molecular landscape of glioblastoma across its various stages. By dissecting these intricate regulatory networks, novel and patient-tailored therapeutic strategies could be devised to improve patient outcomes with this devastating disease.

CircPTK2 as a Valuable Biomarker and Treatment Target in Cancer

Circular RNA (CircRNA)s, a newly discovered type of noncoding RNAs, have been found to play a role in controlling the development and aggressiveness of tumors. Abnormal control of circRNA has been observed in various types of human cancers, including bladder cancer, hepatocellular carcinoma (HCC), breast cancer, and gastric cancer (GC). CircRNAs possess binding sites for microRNAs (miRNAs) and function as miRNA sponges in posttranscriptional regulation. This mechanism has been documented to influence the course of cancer. Significantly, among these putative circRNAs, circular RNA protein tyrosine kinase 2 (circPTK2) exhibited increased expression and displayed a substantial association with adverse clinical characteristics and a negative prognosis. The production of these transcripts occurs via a back-splicing mechanism. The enclosed conformation of circRNAs shields them from destruction and enhances their potential as biomarkers. Gaining insight into the molecular mechanisms involved in these processes would aid in the development of treatment approaches and the discovery of new tumor markers. This article provides a comprehensive assessment of the latest research on the biosynthesis and features of circRNAs. It examines the role of circPTK2 in the diagnosis, treatment, and prognosis evaluation of cancer.

The mechanisms of Chr.9p21.3 risk locus in coronary artery disease: where are we today?

Despite the advancements and release of new therapeutics in the past few years, cardiovascular diseases (CVDs) have remained the number one cause of death worldwide. Genetic variation of a 9p21.3 genomic locus has been identified as the most significant and robust genetic CVD risk marker on the population level, with the strongest association with coronary artery disease (CAD) and other diseases, including diabetes and cancer. Several mechanisms of 9p21.3 in CVDs have been proposed, but their effects on CVDs have remained elusive. Moreover, most of the single nucleotide polymorphisms (SNPs) associated with CAD are located on a sequence of a long noncoding RNA (lncRNA) called ANRIL. ANRIL has several linear and circular splicing isoforms, which seem to have different effects and implications for CVDs. The mechanisms of the 9p21.3 locus and the interplay of its coding and noncoding transcripts in different diseases require further research. Circular RNAs have generally raised interest due to their beneficial features as biomarkers and therapeutic molecules. Here, we review the literature of 9p21.3 from its identification in 2007 and draw the current knowledge on its function, implications in CVDs, and therapeutic potential.

CircZNF609 sponges miR-135b to up-regulate SEMA3A expression to alleviate ox-LDL-induced atherosclerosis

The initiation and progression of atherosclerotic plaque caused by abnormal lipid metabolism is one of the main causes of atherosclerosis (AS). Lipid droplet accumulation has become a novel research pointcut for AS treatment in recent years. In AS patients, miR-135b level was up-regulated relative to the normal cases, which showed negative correlations with the levels of Semaphorin 3A (SEMA3A) and circZNF609, separately. The U937-derived macrophages were cultured with ox-LDL to establish AS models in vitro. After that, the lipid accumulation, inflammation, mitochondrial dysfunction and cell death were evaluated by ORO, ELISA, RT-qPCR, western blot, JC-1 and FCM assays respectively. Transfection of the circZNF609 expression vector notably declined lipid accumulation, attenuated inflammation, reduced mitochondrial dysfunction and inhibited cell death in ox-LDL-stimulated cells. The direct binding of miR-135b to circZNF609 in vitro was confirmed using RIP assay, and SEMA3A expression was up-regulated by circZNF609 overexpression. After manipulating the endogenous expressions of circZNF609, miR-135b and SEMA3A, the above damages in ox-LDL-stimulated cells were rescued by inhibition of miR-135b expression and overexpression of circZNF609 or SEMA3A. Besides, the AS mice model was built to demonstrate the excessive lipid accumulation, increasing inflammation and cell death in AS pathogenesis according to the results of HE staining, ELISA and IHC assays, while these damages were reversed after overexpression of circZNF609 or SEMA3A. In AS models, overexpressed circZNF609 prevents the AS progression through depleting miR-135b expression and subsequent up-regulation of SEMA3A expression to overwhelm lipid accumulation, mitochondrial dysfunction and cell death.

Non-coding RNAs to treat vascular smooth muscle cell dysfunction

Vascular smooth muscle cell (vSMC) dysfunction is a critical contributor to cardiovascular diseases, including atherosclerosis, restenosis and vein graft failure. Recent advances have unveiled a fascinating range of non-coding RNAs (ncRNAs) that play a pivotal role in regulating vSMC function. This review aims to provide an in-depth analysis of the mechanisms underlying vSMC dysfunction and the therapeutic potential of various ncRNAs in mitigating this dysfunction, either preventing or reversing it. We explore the intricate interplay of microRNAs, long-non-coding RNAs and circular RNAs, shedding light on their roles in regulating key signalling pathways associated with vSMC dysfunction. We also discuss the prospects and challenges associated with developing ncRNA-based therapies for this prevalent type of cardiovascular pathology. LINKED ARTICLES: This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

CircRNA-RBAC induces cardiac repair by promoting ribosome biogenesis and cell cycle progression in cardiomyocytes

Ribosome biogenesis (RiBi) is an essential process that controls the protein synthesis rate, but its function in regulating endogenous cardiac regeneration remains unknown. Herein, we investigated the function and underlying mechanism of RiBi-associated circRNAs in cardiomyocyte (CM) proliferation and cardiac regeneration. We used high-throughput sequencing, quantitative PCR and in situ hybridization techniques to identify an adult downregulated circRNA, RiBi-associated circRNA (RBAC), in CMs. A functional study further revealed that RBAC overexpression increased ribosome biogenesis activity and cell cycle progression in CMs, while silencing RBAC decreased ribosome biogenesis activity and cell cycle progression. Moreover, RBAC overexpression induced adult CM proliferation and improved cardiac function after myocardial infarction in adult mice. Mechanistically, RBAC controlled ribosome biogenesis and cell proliferation by regulating the proteasome-dependent degradation of Ddx21, thereby altering the localization of Rps14 and reducing Rb expression. Our findings indicate that RBAC upregulation might be a plausible therapeutic strategy to induce endogenous cardiac regeneration.

Targeting noncoding RNAs to treat atherosclerosis

Noncoding RNAs (ncRNAs) are pivotal for various pathological processes, impacting disease progression. The potential for leveraging ncRNAs to prevent or treat atherosclerosis and associated cardiovascular diseases is of great significance, especially given the increasing prevalence of atherosclerosis in an ageing and sedentary population. Together, these diseases impose a substantial socio-economic burden, demanding innovative therapeutic solutions. This review explores the potential of ncRNAs in atherosclerosis treatment. We commence by examining approaches for identifying and characterizing atherosclerosis-associated ncRNAs. We then delve into the functional aspects of ncRNAs in atherosclerosis development and progression. Additionally, we review current RNA and RNA-targeting molecules in development or under approval for clinical use, offering insights into their pharmacological potential. The importance of improved ncRNA delivery strategies is highlighted. Finally, we suggest avenues for advanced research to accelerate the use of ncRNAs in treating atherosclerosis and mitigating its societal impact. LINKED ARTICLES: This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

ANRIL's Epigenetic Regulation and Its Implications for Cardiovascular Disorders

Cardiovascular disorders (CVDs) are a major global health concern, but their underlying molecular mechanisms are not fully understood. Recent research highlights the role of long noncoding RNAs (lncRNAs), particularly ANRIL, in cardiovascular development and disease. ANRIL, located in the human genome's 9p21 region, significantly regulates cardiovascular pathogenesis. It controls nearby tumor suppressor genes CDKN2A/B through epigenetic pathways, influencing cell growth and senescence. ANRIL interacts with epigenetic modifiers, leading to altered histone modifications and gene expression changes. It also acts as a transcriptional regulator, impacting key genes in CVD development. ANRIL's involvement in cardiovascular epigenetic regulation suggests potential therapeutic strategies. Manipulating ANRIL and its associated epigenetic modifiers could offer new approaches to managing CVDs and preventing their progression. Dysregulation of ANRIL has been linked to various cardiovascular conditions, including coronary artery disease, atherosclerosis, ischemic stroke, and myocardial infarction. This abstract provides insights from recent research, emphasizing ANRIL's significance in the epigenetic landscape of cardiovascular disorders. By shedding light on ANRIL's role in cellular processes and disease development, the abstract highlights its potential as a therapeutic target for addressing CVDs.

Long Noncoding RNA TRIBAL Links the 8q24.13 Locus to Hepatic Lipid Metabolism and Coronary Artery Disease

BACKGROUND

Genome-wide association studies identified a 20-Kb region of chromosome 8 (8q24.13) associated with plasma lipids, hepatic steatosis, and risk for coronary artery disease. The region is proximal to TRIB1, and given its well-established role in lipid regulation in animal models, TRIB1 has been proposed to mediate the contribution of the 8q24.13 locus to these traits. This region overlaps a gene encoding the primate-specific long noncoding RNA transcript TRIBAL/TRIB1AL (TRIB1-associated locus), but the contribution of TRIBAL to coronary artery disease risk remains untested.

METHODS

Using recently available expression quantitative trait loci data and hepatocyte models, we further investigated this locus by Mendelian randomization analysis. Following antisense oligonucleotide targeting of TRIBAL, transcription array, quantitative reverse transcription polymerase chain reaction, and enrichment analyses were performed and effects on apoB and triglyceride secretion were determined.

RESULTS

Mendelian randomization analysis supports a causal relationship between genetically determined hepatic TRIBAL expression and markers of hepatic steatosis and coronary artery disease risk. By contrast, expression data sets did not support expression quantitative trait loci relationships between coronary artery disease-associated variants and TRIB1. TRIBAL suppression reduced the expression of key regulators of triglyceride metabolism and bile acid synthesis. Enrichment analyses identified patterns consistent with impaired metabolic functions, including reduced triglyceride and cholesterol handling ability. Furthermore, TRIBAL suppression was associated with reduced hepatocyte secretion of triglycerides.

CONCLUSIONS

This work identifies TRIBAL as a gene bridging the genotype-phenotype relationship at the 8q24.13 locus with effects on genes regulating hepatocyte lipid metabolism and triglyceride secretion.

Circular RNAs as multifaceted molecular regulators of vital activity and potential biomarkers of aging

Aging presents a significant challenge to health and social care systems due to the increasing proportion of the elderly population. The identification of reliable biomarkers to assess the progression of aging remains an unresolved question. Circular RNAs (circRNAs) are single-stranded covalently closed RNAs. They have been found to regulate various biological processes. CircRNAs are present in human biological fluids, are relatively stable, and accumulate with age, making them promising as biomarkers of aging. Current information on the expression of circRNAs in aging was analyzed using scientific databases. In this review, we have identified key stages in the study of circRNAs during aging and summarized the current understanding of their biogenesis. By focusing on the role of circRNAs in processes that contribute to aging - such as genomic stability, metabolism, cell death, and signaling pathways - we hypothesize that circRNAs may drive the aging process through their age-related accumulation and resultant deregulation. Examples of age-related differential expression of circRNAs in various species, including humans, are provided. This review highlights the importance of finding novel epigenetic biomarkers of aging, beyond the already identified molecules (circFOXO3, circRNA100783, circPVT1), and highlights circRNAs as a potential therapeutic target for the treatment of age-associated diseases.

Identification of Serum-Derived CricRNA Diagnostic Panel and Revealing Their Regulatory Mechanisms in HCV-HCC: A Cross-Sectional Study

Aims and Objectives

Hepatitis C virus (HCV) infection is a significant risk factor for the development of hepatocellular carcinoma (HCC). Serum-derived circular RNAs (circRNAs) play several crucial roles in HCV and HCC. They represent a promising area of research for improving the diagnosis and understanding the mechanisms of HCV-HCC. This study aims to identify a serum-derived circular RNA (circRNA) diagnostic panel for HCV-HCC and to elucidate the regulatory mechanisms underlying their role in cancer progression.

Methods

In this study, data mining and in silico analysis were conducted to identify the role of circular RNAs (hsa_circ_0003288, circ-RNF13, hsa_circ_0004277, circANRIL, circUHRF1, hsa_circ_103047) and their associated biomarkers (IL-6 and NF-κB) in HCV-HCC pathogenesis. Additionally, RT-PCR was performed to assess their expression levels across different study groups (G0 = control, G1 = HCV, G2 = HCC, and G3 = HCV-induced HCC).

Results

The expression levels of circular RNAs, including hsa_circ_0003288, circ-RNF13, hsa_circ_0004277, circANRIL, circUHRF1, and hsa_circ_103047, as well as the biomarkers IL-6 and NF-κB, were significantly elevated in the G3 group compared to the G0 group. ROC analysis also revealed significantly different expression rates for G3 group and G0 group.

Conclusion

The data revealed that cricRNAs panel (hsa_circ_0003288, circ-RNF13, circANRIL, circUHRF1, and hsa_circ_103047) could serve as a diagnostic biomarker and therapeutic target for HCV-induced HCC.

The role of circRNAs in resistance to doxorubicin

Doxorubicin is an anthracyline recognized as an antitumor antibiotic agent. It is widely used in the chemotherapeutic regimens in different types of cancers. Resistance to doxorubicin is a major clinical obstacle and main cause of failure in cancer chemotherapy. Among different mechanisms involved in this process, the role of epigenetic factors has been highlighted. Circular RNAs (circRNAs) have a prominent role in this process. Here, we summarize the recent findings on the role of circRNAs in doxorubicin resistance, particularly in breast cancer and osteosarcoma and underscore their clinical application as potential biomarkers and therapeutic targets in this field. Recognition of the underlying mechanism of circRNAs involvement in doxorubicin resistance will expand our understanding of chemoresistance establishment and may provide a prospect to develop circRNA-based predictive biomarkers of chemotherapy or therapeutic strategies for cancer patients.

GWAS breakthroughs: mapping the journey from one locus to 393 significant coronary artery disease associations

Coronary artery disease (CAD) poses a substantial threat to global health, leading to significant morbidity and mortality worldwide. It has a significant genetic component that has been studied through genome-wide association studies (GWAS) over the past 17 years. These studies have made progress with larger sample sizes, diverse ancestral backgrounds, and the discovery of multiple genomic regions related to CAD risk. In this review, we provide a comprehensive overview of CAD GWAS, including information about the genetic makeup of the disease and the importance of ethnic diversity in these studies. We also discuss challenges of identifying causal genes and variants within GWAS loci with a focus on non-coding regions. Additionally, we highlight tissues and cell types relevant to CAD, and discuss clinical implications of GWAS findings including polygenic risk scores, sex-specific differences in CAD genetics, ethnical aspects of personalized interventions, and GWAS guided drug development.

CircARCN1 aggravates atherosclerosis by regulating HuR-mediated USP31 mRNA in macrophages

AIMS

Circular RNAs (circRNAs) are considered important regulators of biological processes, but their impact on atherosclerosis development, a key factor in coronary artery disease (CAD), has not been fully elucidated. We aimed to investigate their potential use in patients with CAD and the pathogenesis of atherosclerosis.

METHODS AND RESULTS

Patients with stable angina (SA) or acute coronary syndrome (ACS) and controls were selected for transcriptomic screening and quantification of circRNAs in blood cells. We stained carotid plaque samples for circRNAs and performed gain- and loss-of-function studies in vitro. Western blots, protein interaction analysis, and molecular approaches were used to perform the mechanistic study. ApoE-/- mouse models were employed in functional studies with adeno-associated virus-mediated genetic intervention. We demonstrated elevated circARCN1 expression in peripheral blood mononuclear cells from patients with SA or ACS, especially in those with ACS. Furthermore, higher circARCN1 levels were associated with a higher risk of developing SA and ACS. We also observed elevated expression of circARCN1 in carotid artery plaques. Further analysis indicated that circARCN1 was mainly expressed in monocytes and macrophages, which was also confirmed in atherosclerotic plaques. Our in vitro studies provided evidence that circARCN1 affected the interaction between HuR and ubiquitin-specific peptidase 31 (USP31) mRNA, resulting in attenuated USP31-mediated NF-κB activation. Interestingly, macrophage accumulation and inflammation in atherosclerotic plaques were markedly decreased when circARCN1 was knocked down with adeno-associated virus in macrophages of ApoE-/- mice, while circARCN1 overexpression in the model exacerbated atherosclerotic lesions.

CONCLUSIONS

Our findings provide solid evidence macrophagic-expressed circARCN1 plays a role in atherosclerosis development by regulating HuR-mediated USP31 mRNA stability and NF-κB activation, suggesting that circARCN1 may serve as a factor for atherosclerotic lesion formation.

Emerging roles of noncoding RNAs in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic lung disease with limited treatment options and efficacy. Evidence suggests that IPF arises from genetic, environmental, and aging-related factors. The pathogenic mechanisms of IPF primarily involve dysregulated repeated microinjuries to epithelial cells, abnormal fibroblast/myofibroblast activation, and extracellular matrix (ECM) deposition, but thus far, the exact etiology remains unclear. Noncoding RNAs (ncRNAs) play regulatory roles in various biological processes and have been implicated in the pathophysiology of multiple fibrotic diseases, including IPF. This review summarizes the roles of ncRNAs in the pathogenesis of IPF and their potential as diagnostic and therapeutic targets.

Identification of hsa_circ_0018905 as a New Potential Biomarker for Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating autoimmune disease characterized by early onset, for which the interaction of genetic and environmental factors is crucial. Dysregulation of the immune system as well as myelinization-de-myelinization has been shown to correlate with changes in RNA, including non-coding RNAs. Recently, circular RNAs (circRNAs) have emerged as a key player in the complex network of gene dysregulation associated with MS. Despite several efforts, the mechanisms driving circRNA regulation and dysregulation in MS still need to be properly elucidated. Here, we explore the panorama of circRNA expression in PBMCs purified from five newly diagnosed MS patients and five healthy controls (HCs) using the Arraystar Human circRNAs microarray. Experimental validation was then carried out in a validation cohort, and a possible correlation with disease severity was tested. We identified 64 differentially expressed circRNAs, 53 of which were downregulated in PBMCs purified from MS compared to the HCs. The discovery dataset was subsequently validated using qRT-PCR with an independent cohort of 20 RRMS patients and 20 HCs. We validated seven circRNAs differentially expressed in the RRMS group versus the HC group. hsa_circ_0000518, hsa_circ_0000517, hsa_circ_0000514, and hsa_circ_0000511 were significantly upregulated in the MS group, while hsa_circ_0018905, hsa_circ_0048764, and hsa_circ_0003445 were significantly downregulated; Among them, the expression level of hsa_circ_0018905 was significantly decreased in patients showing a higher level of disability and in progressive forms of MS. We described the circRNAs expression profile of PBMCs in newly diagnosed MS patients and proposed hsa_circ_0018905 as potential MS biomarker.

Long Non-coding RNA ANRIL and Its Role in the Development of Age-Related Diseases

ANRIL is known as a lncRNA that has many linear and circular isoforms and its polymorphisms are observed to be associated with the pathogenesis of many diseases including age-related diseases. Age-related diseases including atherosclerosis, ischemic heart disease, and Alzheimer's and Parkinson's disease are the most common cause of mortality in both developed and undeveloped countries and that is why a better understanding of their pathogenesis and underlying mechanisms is necessary for controlling their healthcare burden.In this review, we aim to gather the data of researches which have investigated the role of ANRIL in aging and its related diseases. The conclusions of this paper might give a new insight for decreasing the mortality rate of these diseases.

Role of circular RNAs in preeclampsia (Review)

Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, which affects 3-8% of pregnant individuals worldwide each year. Prevention, diagnosis and treatment of PE are some of the most important problems faced by obstetrics. There is growing evidence that circular RNAs (circRNAs) are involved in the pathogenesis of PE. The present review summarizes the research progress of circRNAs and then describes the expression patterns of circRNAs in PE and their functional mechanisms affecting PE development. The role of circRNAs as biomarkers for the diagnosis of PE, and the research status of circRNAs in PE are summarized in the hope of finding novel strategies for the prevention and treatment of PE.

Novel insights into immune cells modulation of tumor resistance

Tumor resistance poses a significant challenge to effective cancer treatment, making it imperative to explore new therapeutic strategies. Recent studies have highlighted the profound involvement of immune cells in the development of tumor resistance. Within the tumor microenvironment, macrophages undergo polarization into the M2 phenotype, thus promoting the emergence of drug-resistant tumors. Neutrophils contribute to tumor resistance by forming extracellular traps. While T cells and natural killer (NK) cells exert their impact through direct cytotoxicity against tumor cells. Additionally, dendritic cells (DCs) have been implicated in preventing tumor drug resistance by stimulating T cell activation. In this review, we provide a comprehensive summary of the current knowledge regarding immune cell-mediated modulation of tumor resistance at the molecular level, with a particular focus on macrophages, neutrophils, DCs, T cells, and NK cells. The targeting of immune cell modulation exhibits considerable potential for addressing drug resistance, and an in-depth understanding of the molecular interactions between immune cells and tumor cells holds promise for the development of innovative therapies. Furthermore, we explore the clinical implications of these immune cells in the treatment of drug-resistant tumors. This review emphasizes the exploration of novel approaches that harness the functional capabilities of immune cells to effectively overcome drug-resistant tumors.

Progress in application of cyclic single-stranded nucleic acids

Cyclic nucleic acids are biologically stable against nucleic acid exonucleases due to the absence of 5' and 3' termini. Studies of cyclic nucleic acids mainly focus on cyclic single-stranded nucleic acids. Cyclic single-stranded nucleic acids are further divided into circular RNA (circRNA) and circular single-stranded DNA (cssDNA). The synthesis methods of circRNA include lasso-driven cyclization, intron-paired cyclization, intron cyclization, intron complementary pairing-driven cyclization, RNA-binding protein-driven cyclization, and artificial synthesis depending on the source. Its main role is to participate in gene expression and the treatment of some diseases. Circular single-stranded DNA is mainly synthesized by chemical ligation, template-directed enzyme ligation, and new techniques for the efficient preparation of DNA single loops and topologies based on CircLigase. It is mainly used in rolling circle amplification (RCA) technology and in the bioprotection of circular aptamers and second messengers. This review focuses on the types, synthesis methods, and applications of cyclic single-stranded nucleic acids, providing a reference for further research on cyclic single-stranded nucleic acids.

Circular RNA in cancer

Over the past decade, circular RNA (circRNA) research has evolved into a bona fide research field shedding light on the functional consequence of this unique family of RNA molecules in cancer. Although the method of formation and the abundance of circRNAs can differ from their cognate linear mRNA, the spectrum of interacting partners and their resultant cellular functions in oncogenesis are analogous. However, with 10 times more diversity in circRNA variants compared with linear RNA variants, combined with their hyperstability in the cell, circRNAs are equipped to influence every stage of oncogenesis. This is an opportune time to address the breadth of circRNA in cancer focused on their spatiotemporal expression, mutations in biogenesis factors and contemporary functions through each stage of cancer. In this Review, we highlight examples of functional circRNAs in specific cancers, which satisfy critical criteria, including their physical co-association with the target and circRNA abundance at stoichiometrically valid quantities. These considerations are essential to develop strategies for the therapeutic exploitation of circRNAs as biomarkers and targeted anticancer agents.

Research trends and hotspots of circular RNA in cardiovascular disease: A bibliometric analysis

From a global perspective, cardiovascular diseases (CVDs), the leading factor accounting for population mortality, and circRNAs, RNA molecules with stable closed-loop structures, have been proven to be closely related. The latent clinical value and the potential role of circRNAs in CVDs have been attracting increasing, active research interest, but bibliometric studies in this field are still lacking. Thus, in this study, we conducted a bibliometric analysis by using software such as VOSviewer, CiteSpace, Microsoft Excel, and the R package to determine the current research progress and hotspots and ultimately provide an overview of the development trends and future frontiers in this field. In our study, based on our search strategy, a total of 1206 publications published before July 31, 2023 were accessed from the WOSCC database. According to our findings, there is a notable increasing trend in global publications in the field of circRNA in CVDs. China was found to be the dominant country in terms of publication number, but a lack of high-quality articles was a significant fault. A cluster analysis on the co-cited references indicated that dilated cardiomyopathy, AMI, and cardiac hypertrophy are the greatest objects of concern. In contrast, a keywords analysis indicated that high importance has been ascribed to MI, abdominal aortic aneurysm, cell proliferation, and coronary artery diseases.

Circular RNAs in human diseases

Circular RNAs (circRNAs) are a unique class of RNA molecules formed through back-splicing rather than linear splicing. As an emerging field in molecular biology, circRNAs have garnered significant attention due to their distinct structure and potential functional implications. A comprehensive understanding of circRNAs' functions and potential clinical applications remains elusive despite accumulating evidence of their involvement in disease pathogenesis. Recent research highlights their significant roles in various human diseases, but comprehensive reviews on their functions and applications remain scarce. This review provides an in-depth examination of circRNAs, focusing first on their involvement in non-neoplastic diseases such as respiratory, endocrine, metabolic, musculoskeletal, cardiovascular, and renal disorders. We then explore their roles in tumors, with particular emphasis on exosomal circular RNAs, which are crucial for cancer initiation, progression, and resistance to treatment. By detailing their biogenesis, functions, and impact on disease mechanisms, this review underscores the potential of circRNAs as diagnostic biomarkers and therapeutic targets. The review not only enhances our understanding of circRNAs' roles in specific diseases and tumor types but also highlights their potential as novel diagnostic and therapeutic tools, thereby paving the way for future clinical investigations and potential therapeutic interventions.

CircZFR promotes colorectal cancer progression via stabilizing BCLAF1 and regulating the miR-3127-5p/RTKN2 axis

Aberrant expression of circular RNAs (circRNAs) is frequently linked to colorectal cancer (CRC). Here, we identified circZFR as a promising biomarker for CRC diagnosis and prognosis. CircZFR was upregulated in CRC tissues and serum exosomes and its level was linked to cancer incidence, advanced-stages, and metastasis. In both in vitro and in vivo settings, circZFR promoted the growth and spread while suppressing apoptosis of CRC. Exosomes with circZFR overexpression promoted the proliferation and migration of cocultured CRC cells. Mechanistically, epithelial splicing regulatory protein 1 (ESRP1) in CRC cells may enhance the production of circZFR. BCL2-associated transcription factor 1 (BCLAF1) bound to circZFR, which prevented its ubiquitinated degradation. Additionally, circZFR sponged miR-3127-5p to boost rhotekin 2 (RTKN2) expression. Our TCP1-CD-QDs nanocarrier was able to carry and deliver circZFR siRNA (si-circZFR) to the vasculature of CRC tissues and cells, which inhibited the growth of tumors in patient-derived xenograft (PDX) models. Taken together, our results show that circZFR is an oncogenic circRNA, which promotes the development and spread of CRC in a BCLAF1 and miR-3127-5p-dependent manner. CircZFR is a possible serum biopsy marker for the diagnosis and a desirable target for further treatment of CRC.

Emerging Roles of Circular RNA in Macrophage Activation and Inflammatory Lung Responses

Circular RNA (circRNA) is a type of single-stranded RNA that forms a covalently closed continuous loop, unlike linear RNA. The expression of circRNAs in mammals is often conserved across species and shows tissue and cell specificity. Some circRNA serve as gene regulators. However, the biological function of most circRNAs is unclear. CircRNA does not have 5' or 3' ends. The unique structure of circRNAs provides them with a much longer half-life and more resistance to RNase R than linear RNAs. Inflammatory lung responses occur in the pathogenesis and recovery of many lung diseases. Macrophages form the first line of host defense/innate immune responses and initiate/mediate lung inflammation. For example, in bacterial pneumonia, upon pro-inflammatory activation, they release early response cytokines/chemokines that recruit neutrophils, macrophages, and lymphocytes to sites of infection and clear pathogens. The functional effects and mechanisms by which circRNAs exert physiological or pathological roles in macrophage activation and lung inflammation remain poorly understood. In this article, we will review the current understanding and progress of circRNA biogenesis, regulation, secretion, and degradation. Furthermore, we will review the current reports on the role of circRNAs in macrophage activation and polarization, as well as in the process of inflammatory lung responses.

Noncanonical formation of SNX5 gene-derived circular RNA regulates cancer growth

Oral squamous cell carcinoma (OSCC) is a prevalent cancer worldwide, exhibiting unique regional prevalence. Despite advancements in diagnostics and therapy, the 5-year survival rate for patients has seen limited improvement. A deeper understanding of OSCC pathogenesis, especially its molecular underpinnings, is essential for improving detection, prevention, and treatment. In this context, noncoding RNAs, such as circular RNAs (circRNAs), have gained recognition as crucial regulators and potential biomarkers in OSCC progression. Our study highlights the discovery of previously uncharacterized circRNAs, including a SNX5 gene-derived circRNA, circSNX5, through deep sequencing of OSCC patient tissue transcriptomes. We established circSNX5's tumor-specific expression and its strong correlation with patient survival using structure-specific and quantitative PCR analyses. In vitro and in vivo experiments underscored circSNX5 RNA's regulatory role in cancer growth and metastasis. Further, our omics profiling and functional assays revealed that ADAM10 is a critical effector in circSNX5-mediated cancer progression, with circSNX5 maintaining ADAM10 expression by sponging miR-323. This novel circRNA-miRNA-mRNA regulatory axis significantly contributes to oral cancer progression and malignancy. Moreover, we discovered that circSNX5 RNA is produced via noncanonical sequential back-splicing of pre-mRNA, a process negatively regulated by the RNA-binding protein STAU1. This finding adds a new dimension to our understanding of exonic circRNA biogenesis in the eukaryotic transcriptome. Collectively, our findings offer a detailed mechanistic dissection and functional interpretation of a novel circRNA, shedding light on the role of the noncoding transcriptome in cancer biology and potentially paving the way for innovative therapeutic strategies.

Nanoparticles-Delivered Circular RNA Strategy as a Novel Antitumor Approach

Anticancer therapy urgently needs the development of novel strategies. An innovative molecular target is represented by circular RNAs (circRNAs), single-strand RNA molecules with the 5' and 3' ends joined, characterized by a high stability. Although circRNA properties and biological functions have only been partially elucidated, their relationship and involvement in the onset and progression of cancer have emerged. Specific targeting of circRNAs may be obtained with antisense oligonucleotides and silencing RNAs. Nanotechnology is at the forefront of research for perfecting their delivery. Continuous efforts have been made to develop novel nanoparticles (NPs) and improve their performance, materials, and properties regarding biocompatibility and targeting capabilities. Applications in various fields, from imaging to gene therapy, have been explored. This review sums up the smart strategies developed to directly target circRNAs with the fruitful application of NPs in this context.

Circular RNA in Cardiovascular Diseases: Biogenesis, Function and Application

Cardiovascular diseases pose a significant public health challenge globally, necessitating the development of effective treatments to mitigate the risk of cardiovascular diseases. Recently, circular RNAs (circRNAs), a novel class of non-coding RNAs, have been recognized for their role in cardiovascular disease. Aberrant expression of circRNAs is closely linked with changes in various cellular and pathophysiological processes within the cardiovascular system, including metabolism, proliferation, stress response, and cell death. Functionally, circRNAs serve multiple roles, such as acting as a microRNA sponge, providing scaffolds for proteins, and participating in protein translation. Owing to their unique properties, circRNAs may represent a promising biomarker for predicting disease progression and a potential target for cardiovascular drug development. This review comprehensively examines the properties, biogenesis, and potential mechanisms of circRNAs, enhancing understanding of their role in the pathophysiological processes impacting cardiovascular disease. Furthermore, the prospective clinical applications of circRNAs in the diagnosis, prognosis, and treatment of cardiovascular disease are addressed.

Long non-coding RNAs in the nucleolus: Biogenesis, regulation, and function

The nucleolus functions as a multi-layered regulatory hub for ribosomal RNA (rRNA) biogenesis and ribosome assembly. Long noncoding RNAs (lncRNAs) in the nucleolus, originated from transcription by different RNA polymerases, have emerged as critical players in not only fine-tuning rRNA transcription and processing, but also shaping the organization of the multi-phase nucleolar condensate. Here, we review the diverse molecular mechanisms by which functional lncRNAs operate in the nucleolus, as well as their profound implications in a variety of biological processes. We also highlight the development of emerging molecular tools for characterizing and manipulating RNA function in living cells, and how application of such tools in the nucleolus might enable the discovery of additional insights and potential therapeutic strategies.